KR100543155B1 - Synchrotilt chair with adjustable seat, back and energy mechanism - Google Patents

Abstract

A base assembly 21 comprising a base frame, a back frame 30 pivoted relative to the base frame for movement between an upright position and an inclined position, and slidably supported on the base frame and pivoted relative to the base frame forward A chair 20 is provided that includes a seat 24 that moves to the front, and the rear thereof moves forward and downward with the backrest frame when tilted. The flexible back is connected to the back frame in the upper and lower positions and lumbar adjustment is provided for improved lumbar force / support and shape. The seat is provided with seat depth control and active and passive thigh flexion support. A novel energy mechanism 27 is provided that includes a lateral spring 28 and a moment arm movement regulator 29 for adjusting spring tension on the back frame. The moment arm travel regulator is radially adjustable and includes an overtorque device to prevent damage to the elements of the energy appliance.

Synchronous Tilt Chair, Seat, Base Frame, Back Frame, Upright Position, Tilt Position

Description

SYNCHROTILT CHAIR WITH ADJUSTABLE SEAT, BACK AND ENERGY MECHANISM} WITH ADJUSTABLE SEATS, BACKBACK AND ENERGY DEVICES

background

The present invention relates to a chair having a tiltable backrest, a movable / tiltable seat which moves synchronously as the backrest tilts, and an adjustable energy mechanism for supporting the backrest while tilting.

Synchronous inclined chairs having a base assembly having a control unit, an inclined backrest pivoted relative to the control unit, and a seat operably mounted to the backrest to be synchronously movable according to the inclination of the backrest include a knoblock or the like. US Pat. Nos. 5,050,931, 5,567,012, 4,744,603 and 4,776,633. The chair of the prior art is combined with a chair support structure in combination with the work / task during body movement (ie when the backrest is in an upright position) and during movement of the body during inclination / rest (ie when the backrest is in an inclined position). Case), incorporates a semi-rigid flexible shell that provides easy posture support. The chair of the prior art moves the upper body of the seated user away from the work surface of the user as the user is inclined, thus increasing the space for the user to move. However, users often want to stay close to their work surface, even in a resting position by tilting their bodies and with continuous posture support, and want to continue working on the work surface. To this end, in the synchronous tilting chair of US Pat. No. 5,050,931, the user must move their chair forward in order to easily reach their working surface even after they are tilted. The user must also push out when moving back to the upright position to avoid colliding with the working surface. "Moving" back and forth once or twice is not a serious problem, but users, such as computer-based office workers, often move constantly between upright and inclined positions, and the process of repeatedly moving back and forth is annoying and confusing. do. Indeed, moving around without staying in a single static position is important for maintaining the health of the back of a worker with a job that has to sit for a long time.

Another disadvantage of significantly moving backwards while the torso of the seated user is tilted is that the overall center of gravity of the user moves backwards. By providing a more constant center of gravity, it is possible to design tiltable chairs that are more inclined or height adjusted without sacrificing the overall stability of the chair. In addition, the tiltable chair, with the torso of the seated user moving significantly to the rear, has a relatively large footprint, so that these chairs may collide with furniture or walls when used in narrow offices or narrow work spaces. have. Another disadvantage is that in these conventional tiltable chairs a large spring is required to support the backrest, which is difficult to adjust by the force generated by the spring. However, the tension of these springs should preferably be adjusted so that heavier and lighter users can adjust the chair to obtain the proper support size.             

As a result, the seated user wants to be able to easily adjust the spring tension to provide support for the user's back while tilting. Heavier / large people not only require support of larger / firm backs than lighter / smaller people, but also require a greater rate of change in the amount of support required while tilting. In particular, light / small people need a smaller initial support level when they start to slope and moderately increased support levels as they continue to slope, while heavy / big people considerably when they start to slope. It requires a large minimum initial support level and a significantly increased support level as they continue to slope. In other words, it is desirable to provide a chair that can be easily adjusted at the initial level of support for the backrest during initial tilting, and that the rate of increase of support is automatically adjusted during tilting. In addition, (1) while seated, (2) by a relatively weak user, (3) is easily adjusted using an easily adjustable adjustment control unit, and (4) "overtorque" is applied to the control unit. It would be desirable to provide a mechanism having a control that is not easily damaged by a relatively strong person. It would also be desirable to provide a compact spring arrangement to provide an optimal shape and to minimize material cost and size.

Manufacturers have found that proper lumbar support is of great importance to prevent discomfort in the lower back and to reduce operator stress for long sitting users. The problem is that the spine shape and body shape of the worker are so diverse that it is impossible to satisfy all workers with the same shape. In addition, the level of firmness or bearing capacity required near the lumbar spine is different for each person, as the seated user performs different tasks, and / or as it slopes in the chair, and / or becomes fatigued. It can change accordingly. Indeed, static lumbar support is undesirable. Instead, it is desirable to provide the desired level of support over different lumbar vertebrae shapes and working hours. Thus, an adjustable lumbar spine system configured to vary the shape and force of lumbar support is desirable. At the same time, the adjustable lumbar system should be simple and easy to operate, easy to access while seated, not mechanically complex, low in price, and aesthetically and visually satisfactory. Preferably, adjustment of shape and / or force in the lumbar region does not wrinkle the fabric of the chair and should not result in loose / stretched portions of the fabric that are undesirable.

Modern consumers and chair buyers require a wide variety of chair options and features, so many options and features are often designed on the chair seat. However, the improvement of the seat is required in order for the weight of the seated user to be properly supported on the chair seat, but at the same time the thigh area of the seated user is very different in shape and size of the seated buttock and thigh of the seated user. There is a need for a comfortable and adjustable support. In addition, these options and features minimize the number of components to the maximum, maximize the use of common components for other options, maximize the efficiency of manufacturing and assembly, and maximize the ease of logic of adjustment and adjustment control positions. It is important to incorporate the chair structure in such a way that a visually satisfactory design can be obtained.

In particular, with regard to a synchronous tilting chair in which the seat and the backrest are pivoted by synchronous angular movement, many synchronous tilting chairs have been designed such that the seat pivots back as the user tilts. Often, however, these known sheet structures are pivoted about a sheet pivot axis located rearward of the front edge of the sheet. This raises the knee of the seated user, resulting in undesired pressure on the thigh of the seated user when tilted. Designing the flexible anterior lip inside the seat does not completely solve the undesired thigh compression because the thigh is supported by at least about half of the seat instead of by the front lip of the seat. Positioning the flexible area substantially rearward within the seat, such as behind the seated user's hip joint, also slides downward and forward of the chair back and forward when the chair tilts the seated user's upper body weight / Because it tends to slide, it does not solve the problem. This will then cause the seated user to slide away in front of the seat, unless the seat includes a rear area formed to support the seated user against this forward slip / slide movement. This problem is due to the fact that the hip joints of different seated users are not always located in the same relative position on the chair seat, so that one seat design is suitable for one seated user but not for another seated user. Compound.

Inclined chairs have gained wide and outstanding support in the chair industry. The tiltable chair often includes a backrest frame pivoted by the backrest pivot to the opposite side of the base or control housing to define the backrest tilt axis. The problem is that the backrest pivot is not always perfectly aligned with the backslope axle. This misalignment causes the backrest pivot to be inclined at an angle to the backrest inclination axis, the backrest pivot to be parallel to, but not aligned with, the backrest inclination axis, or the backrest pivot as the user sits on or inclines the chair. Can be changed. The correct result is that at least one chair element must be bent while the backrest is tilted and provided mechanically so as not to be constrained. Typically, the control housing or back frame structure is all deformed and / or the bearings must have sufficient margin to compensate for misalignment. If the deformation is large enough or the chair element is not designed for this flexibility, one of the chair elements may break, fail or break down over time by periodic fatigue failure. Another problem is that the bearings of the backrest pivot quickly wear out from the large forces generated by misalignment. This causes the backrest to become loose, which may not be desirable in certain situations. A similar problem may arise in a synchronous tilting chair having a space spaced from the seat pivot that the seat is not exactly aligned with the seat tilt axis. It should be noted that the seat pivot must also support most of the weight of the seated user, thus increasing the stress level of the seat pivot.

Another problem with known chair back pivots is that the assembly is cumbersome, and / or not only manual, but also expensive, as the holes must be aligned to accommodate the pivot pins / axes, and the pivot pins / axes are correct. This is because it should not be over tightened or fixed. In particular, the pivot pin / axis during fixation will not be able to apply overtorque or the assembly will be constrained, nor will it be able to apply low torque or the assembly will be undesirably loosened and separated.

In addition to the above requirements, any backrest and seat pivot should be included in the chair structure to provide the desired shape, since the chair is often located in a very visible area.

Therefore, a chair structure that solves the above-mentioned problems is desirable.

Summary of the Invention

In one aspect of the invention, the chair operates on a base assembly having a control housing having opposing side flanges and side pivots, a backrest pivoted relative to the base assembly to move between an upright position and an inclined position, and a base assembly A seat possibly connected to the backrest to support and move synchronously in the same orientation as the backrest. An energy device is provided to bias the backrest toward the upright position. The energy mechanism includes an elongate / compressible spring positioned transversely in a control housing having one end supported on one of the side flanges, the spring engagement pivoting against the side pivot and engaging with the free end of the spring. And a lever having a seat convenience operably connected to the portion and the seat. The side pivot, spring engagement and seat convenience are spaced apart from each other and the spring is arranged to bias the lever with respect to a support point located generally on the side pivot to bias the backrest toward the upright position.

In another aspect of the invention, the chair comprises a control housing comprising a pivot member, a tiltable backrest operably connected to the control housing for movement between an upright position and an inclined position, and an energy source within the control housing. The chair also includes an improved adjustable back tension control for the chair wherein the pivot member is adjustable and the lever engages the energy source and pivot member and is operably connected to the backrest to facilitate the backrest in an upright position. The lever and pivot member have at least one non-slip interfacing surface that is curved such that the interfacing surfaces are joined to define a support point at which the lever is rotated while the backrest is tilted, and the support point is also used while the pivot member is operating an energy source. Change the position adjusted to change the moment arm.

In another aspect of the invention, the chair supports a base assembly, an element comprising one of a tiltable back and a movable seat pivoted relative to the base assembly for movement between the first and second positions, and a support on the base assembly. And a spring having one end thereof and the other end operatively connected to the element. The spring has a predetermined length and is simultaneously compressed longitudinally along the predetermined length and laterally bent laterally along the length as the element is moved from the first position to the second position.

In another aspect of the invention, a chair is a base assembly comprising a control housing, a seat slidably supported on the control housing, pivoted relative to the base assembly for movement between an upright position and an inclined position and operatively actuated on the seat. A backrest frame attached to synchronize the pivot movement of the backrest frame and the slide movement of the seat, a first leg having a predetermined length and engaging with one end of the coil spring, and a second leg extending generally parallel to the length of the spring; And a spring having an L-shaped torque member. The first leg pivotally engages the control housing in a position spaced from the end of the spring. The second leg is operably connected to one of the seat and the back frame such that the spring biases the torque member in a manner that biases the back frame toward the upright position.

In another aspect of the invention, a chair comprises a base assembly comprising a control housing, a seat slidably supported on the control housing, the base assembly being relative to the base frame for movement between an upright position and an inclined position. It is pivoted and operatively attached to the seat to synchronize the pivot movement of the back frame and the slide movement of the seat. The control housing defines a region that is relatively thin and extends horizontally under the seat. The adjustable energy mechanism is adjustable pivotally supporting an adjustable energy source, a lever operably connected between the energy source and the seat, and a lever that operatively controls the force transmitted from the energy source to the seat through the lever. Member. The energy source, the lever, and the regulating member are movable in the horizontal direction to operate in a region that is relatively thin and extends horizontally.

In another aspect of the invention, the chair control unit comprises a control housing, an element operably attached to the control housing for movement between a plurality of positions, an actuator on the control housing operably connected to the element for controlling movement of the element. A manually operable handle for operating the actuator, and an overtorque device for connecting the handle to the actuator. The overtorque device is configured to limit the maximum amount of force transmitted from the handle to the actuator to prevent damage to the chair control.

In one aspect, the present invention relates to a base assembly comprising opposing side arms, a back frame having an end of a predetermined shape to pivot relative to the side arm at the back pivot for rotation about the back tilt axis, and the seat tilt axis relative to the seat tilt axis. And a chair having a seat pivoted about an end of a predetermined shape in the seat pivot for rotation. The at least one back pivot and seat pivot are such that the bearing is not constrained and rotates with respect to the stud even when the bearing element is misaligned with one of the connected studs of the back tilt and seat tilt axes. An inclined axis connected with at least one axis and a support element that flexibly supports the bearing element for misaligned rotational movement. In a narrower aspect, the support element is made of elastic rubber.

In another aspect of the present invention, the chair has a base assembly comprising side arms and a back frame having an end portion of the predetermined shape to pivot relative to the side arms at the back pivot for rotation about the backrest tilt axis. The back frame is flexible enough to allow ends of the desired shape to be flexible and spaced apart during assembly. The end and side arms of the predetermined shape have adjacent faces, one of which has a recess therein. Bearing arrangements are located on the respective backrest pivots to pivotally connect the side arms to the respective ends of the predetermined shape. The bearing arrangement includes a stud extending into the recess and a bearing rotatably coupling the stud, the bearing being removable from the recess but partially retained within the recess near adjacent surfaces.

In another aspect, the present invention includes a chair assembly method comprising providing a chair element having laterally extending and facing projections, and providing a back frame having an end of a predetermined shape with a recess. do. The method is capable of spaced apart bent ends of the back frame, simultaneously positioning recesses of the end of the predetermined shape on the projection, holding the back frame in place and pivoting the back frame to the chair element. Releasing the back frame to elastically restore the back frame to an initial shape that connects securely.

In another aspect of the invention, the control unit comprises a control housing, a single stored energy source located within the control housing to provide a compressive force, and a lever operably interconnected with the single energy source for movement between the upright and inclined positions. Include. The single stored energy source applies a pretension to bias the lever towards the upright position and provides resistance to the tilt of the lever when tilted. The control further includes a controller for adjusting the preliminary tension of the storage energy source and the tilt rate of the lever, the controller being configured to adjust without an actuator that must overcome the compressive force of the single storage energy source.

In another aspect of the invention, a chair is operable with a base assembly comprising a control housing, a single stored energy source located within the control housing to provide compressive force, and the single energy source for movement between an upright position and an inclined position. And a back support that is interconnected. A single stored energy source applies a preliminary tension to bias the back support delay towards the upright position and provides resistance to the tilt of the back support when tilted. The control further includes a controller for adjusting the preliminary tension of the stored energy source and the tilt rate of the back support, the controller defining an adjustable support point that can be adjusted without overcoming the compressive force of the single stored energy source. It includes.

In another aspect of the invention, the control portion includes a control housing, a stored energy source located within the control housing, and a back support first lever operably interconnected with the energy source for movement between the upright and inclined positions. . The storage energy source applies a pretension to bias the first lever towards the upright position and provides resistance to the tilt of the first lever when tilted. The control further includes a controller for adjusting the preliminary tension of the stored energy source of the first lever. The controller includes a crank lever in the control housing. The crank lever has one end coupled with the stored energy source and the other end operatively interconnected with the first lever. The crank lever has a portion between the two ends forming the support point, so that the stored energy source biases the crank lever relative to the support point to bias the first lever toward an upright position.

In another aspect of the invention, the control portion includes a control housing, a stored energy source located within the control housing, and a first lever operably interconnected with the energy source for movement between an upright position and an inclined position. The storage energy source applies a pretension to bias the first lever towards the upright position and provides resistance to the tilt of the first lever when tilted. The control further includes an adjustable controller to controllably control the preliminary tension of the stored energy source. The controller includes a manually operable handle to control the preliminary tension of the stored energy source and an overtorque device configured to limit the physical force transmitted from the handle to the controller.

These and other features and advantages of the present invention will become apparent to those skilled in the art by reference to the following specification, claims and appended drawings.

Detailed description of the drawings

1 to 3 are front, back and side perspective views of an inclined chair according to the present invention.

4A and 4B are exploded perspective views showing the upper and lower portions of the chair shown in FIG.

5 and 6 are side views of the chair shown in FIG. 1, FIG. 5 shows the flexibility and adjustability of the chair in an upright position, and FIG. 6 shows the movement of the backrest and seat while inclined.

Fig. 7 is a front view of the chair shown in Fig. 1 with the lower seat cover removed.

Fig. 8 is a plan view showing a control unit including a main energy mechanism, a moment arm movement adjusting mechanism, and a back rest stop mechanism, wherein the main energy mechanism is adjusted to a relatively low torque position, and the seat rests when the backrest is in an upright position. Towards the position to be rearward in position, the back stop mechanism shows that it is in an intermediate position to restrict the backrest to allow maximum tilt.

FIG. 8A is a perspective view of the base frame and the chair control unit shown in FIG. 8, in which some seat and back support structures are shown in dashed lines, and some of the controls are shown in solid lines to show relative positions.

Fig. 9 is a perspective view showing the control unit and the main energy mechanism shown in Fig. 8, which is adjusted so that the main energy mechanism is in a low torque position, and the backrest is in an upright position so that the seat moves rearward.

Fig. 9A is a perspective view of the control and main energy mechanism shown in Fig. 9, with the main energy mechanism being adjusted to a low torque position, but shown as if the backrest is in an inclined position such that the seat is moved forward and the spring is compressed. .

FIG. 9B is a perspective view of the control and main energy mechanism shown in FIG. 9, with the main energy mechanism adjusted to a high torque position and shown as if the backrest is in an upright position such that the seat moves rearward.

FIG. 9C is a perspective view of the control and main energy mechanism shown in FIG. 9, the main energy mechanism being adjusted to a high torque position, but shown as if the backrest is in an inclined position such that the seat is moved forward and the spring is compressed. .

FIG. 9D is a graph showing the torsional versus angular deflection curves for the main energy mechanism of FIGS. 9-9C, the curves being from the upper curve (the long moment arm coupling of the main spring) and the low torque showing the force obtained from the high torque. A lower curve showing the resulting force (short moment arm engagement of the main spring).             

Fig. 10 is an enlarged plan view of the control unit and the main energy mechanism shown in Fig. 8, which includes a control unit for the back rest stop mechanism, and the back stop mechanism is shown in the released position.

11 is an exploded view showing a mechanism for adjusting a main energy mechanism including an overtorque release mechanism.

FIG. 11A is a plan view showing a link associated with the modified backrest regular controller, FIG. 11B is a partially enlarged cutaway sectional view of the circular region of FIG. 11A, and FIG. 11C is a sectional view taken along the line XIC-XIC of FIG.

FIG. 12 is a side view of the backrest assembly shown in FIG. 1, comprising a backrest frame and a flexible backshell, including the skeleton and body of a seated user, the backshell being shown in a convex forward shape in a solid line; FIG. Other flexible shapes are shown with dashed lines and dashed lines.

12A is an enlarged perspective view of the backrest frame shown in FIG. 4A, with the molded polymer outer shell being transparent so that the backrest frame can easily see the reinforcement.

12B and 12C are cross-sectional views taken along lines XXIIB-XXIIB and XXIIC-XXIIC of FIG. 12A.

12D-12I illustrate additional embodiments of a flexible back shell structure adapted to move in response to the seated user's back.

12J is an exploded perspective view of the torsion adjustable lumbar support spring mechanism shown in FIG. 4A, and FIG. 12J1 is an exploded view of the hub and spring connections of FIG. 12J taken from opposite sides of the hub.

12K is an exploded perspective view of a modified torsion adjustable lumbar support spring mechanism.

12L and 12L1 are side views of the instrument shown in FIG. 12K adjusted to a low torque position, FIGS. 12M and 12M1 are side views of the instrument adjusted to a high torque position, and FIGS. 12L and 12M show spring drivers in detail. 121 and 12M1 show the lever in detail.

FIG. 12N is a partial sectional view of the backrest structure shown in FIG. 12; FIG.

Figure 13 is a side cross-sectional view taken along line XIII-XIII, showing a pivot portion interconnecting the base frame to the back frame and interconnecting the back frame to the seat frame.

FIG. 13A is a side cross-sectional view of a modified pivot similar to FIG. 13 but showing another structure.

14A and 14B are perspective and front views of the upper connector connecting the back shell to the back frame.

Figure 15 is a rear view of the backrest shell shown in Figure 4A.

Figure 16 is a perspective view of the backrest including the vertically adjustable lumbar support mechanism shown in Figure 4A.

17 and 18 are front and top views of the vertically adjustable lumbar support mechanism shown in FIG.

FIG. 19 is an illustration of the slide frame of the vertically adjustable lumbar support mechanism shown in FIG.

FIG. 20 is a partial planar cross-sectional view showing the laterally extending handle of the vertically adjustable lumbar support mechanism shown in FIG. 17 and the attachment of the handle to the sliding member of the lumbar support mechanism. FIG.

Figure 21 includes a seat carrier and a seat lower carrier / support frame slidably mounted on the seat carrier, the seat lower carrier / support frame is partially cut to show a bearing on the seat carrier, and the seat cushion A perspective view of the depth adjustable sheet shown in FIG. 4B, removed to reveal the part.

FIG. 22 is a top view of the seat carrier shown in FIG. 21 with the seat lower carrier / rear frame removed, but with a seat frame sliding bearing and a seat carrier depth adjustable stop device shown.

FIG. 23 is a top perspective view of the seat lower carrier / rear frame and seat carrier shown in FIG. 21, including a depth adjustment control handle, a link, and a latch holding the selected depth position of the seat.

Figures 24 and 25 are side views of the depth adjustable sheet shown in Figure 21, Figure 24 shows the sheet adjusted to the maximum sheet depth, Figure 25 shows the sheet adjusted to the minimum sheet depth, Figures 24 and Figure 25 also illustrates a manually adjustable "active" thigh support system that includes a gas spring to adjust the front portion of the seat shell to provide optimal thigh support.

Figure 26 shows a seat carrier (usually broken line), seat carrier / rear frame, an active thigh support system with gas springs and reinforcement plates for adjustable support of the front portion of the seat, and seat and depth setting latches. 24 is a plan view of the seat support structure shown in FIGS. 24 and 25 that includes a portion of a depth adjustment mechanism that includes a stop for limiting front and rear maximum depth adjustment.

FIG. 26A is a cross sectional view taken along the line XXVIA-XXVIA in FIG. 26, showing a stop for the depth adjustment mechanism.

27 and 28 are top and bottom perspective views of the sheet support structure shown in FIG.

29 and 30 are top and bottom perspective views showing a sheet similar to that shown in FIG. 26, but with a manually adjustable thigh support system replaced by a manual thigh support system that includes a leaf spring for supporting the front portion of the seat. Shows that.

FIG. 31 is a bottom perspective view of the bracket and guide for supporting the end of the leaf spring shown in FIG. 30, but showing a state where the thigh support front portion of the seat is bent downward to bend the leaf spring toward a flat compression state; .

Detailed description of the preferred embodiment

For purposes of this specification, the terms "top", "bottom", "right", "left", "rear", "front", "vertical", and "horizontal" and their derivatives refer to a person seated in a chair. The present invention is related to the present invention oriented as shown in FIG. However, it should be understood that the present invention may assume various other directions except where specifically indicated. In addition, it is to be understood that the specific apparatus and processes shown in the accompanying drawings and described in the following specification are merely exemplary embodiments of the inventive concept as defined in the appended claims. Thus, specific dimensions and other features of the embodiments disclosed herein are not to be unnecessarily limited, unless they differ from the representation of the claims.

Chair structure 20, Figures 1 and 2, embodying the present invention, has a cast base assembly 21 and a base 21 for movement about a fixed backrest tilt axis 23 between an upright position and an inclined position. Tiltable backrest assembly 22 pivoted about. The seat assembly 24 (FIG. 6) is pivoted rearward relative to the backrest 22 for movement relative to the seat tilt axis 25. FIG. The seat inclination axis 25 is offset downward and rearward from the backrest inclination axis 23, and the seat 24 is slidably supported from the front on the base 21 by the linear bearing so that the seat 24 is forward. It is slid and its rear is rotated forward and downward in synchronous movement to the inclination of the backrest 22 (see FIG. 6). Synchronous movement first moves the backrest relative to the seat at an angular sync ratio of about 2.5: 1, and moves the backrest relative to the seat at an angular sync ratio of about 5: 1 at a nearly fully inclined position. The movement of the seat 24 and the back 22 during inclination provides a very comfortable seating that makes the seated user feel very stable and secure. This is partly due to the fact that the movement keeps the center of gravity of the seated user relatively constant and the seated user in a relatively balanced position on the chair base. In addition, the forward sliding / synchronous movement is more seated than conventional synchronous inclined chair structures, which, if not removed, have a problem that it is much less likely to move backwards after tilting forward and then backwards when moving towards the upright position. Keep the user around the workbench while the user is tilted. Another advantage is that the chair structure 20 can be used close to the wall behind the chair or in a small office, resulting in less disturbance from office furniture during the inclination. In addition, the spring 28 for biasing the back 22 toward the upright position can potentially be reduced in size because of the reduced back movement of the weight of the seated user in the current chair.

The base includes a control housing 26. The main energy device 27 (FIG. 8) is operatively located in the control housing 26 to bias the seat 24 backwards. By the interconnection of the back 22 and the seat 24, the rear bias of the seat 24 then biases the back 22 towards the upright position. The main energy mechanism 27 (Fig. 8) includes a main spring 28 positioned transversely in the control housing 26 which is operatively engaged with the torque member or lever 54. The tension and torque provided by the main spring 28 are substantially adjustable via an adjustable moment arm movement (MAS) system 29 located in the control housing 26. The sheathing cover 26 ′ (FIG. 1) covers the area between the control housing 26 and the lower side of the seat 24. The backrest assembly 22 includes a backrest support or backrest frame 30 (FIG. 4A) having a structure defining a pivot / axis 23, 25. As shown in FIG. The flexible / flexible back shell structure 31 is pivoted against the back frame 30 at the upper and lower connections 32 and 33 in a manner that provides a comfortable and suitable back support. A torsionally adjustable lumbar support spring mechanism 34 is provided to bias the backrest shell 31 forward in a convex curve shape optimized to provide good lumbar pressure. The vertically adjustable lumbar support 35 (FIG. 16) is operably mounted on the backrest shell 31 for vertical movement to provide an optimal shape and pressure position relative to the front support surface on the backrest 22. FIG. The seat 24 is provided with a variety of options for providing enhanced chair function, such as a back stop mechanism 36 (FIG. 8) that adjustably engages the seat 24 to limit the inclination of the backrest 22. FIG. The seat 24 also includes active and passive thigh support options (see FIGS. 24 and 30, respectively), seat depth adjustments (see FIGS. 28 and 25), and other seat options, as described below. can do.

Base assembly

Base assembly 21 (FIG. 1) includes a bottom bonding support 39 having a central hub 40 and a cast leg 41 extending radially attached to the central hub 40 in a spider shape. The insertably extendable central strut 42 is located in the central hub 40 and includes a gas spring operable to insert the strut 42 to raise the height of the chair. The control housing 26 of the base assembly 21 is fan-shaped (FIG. 11) and includes a bottom panel and flanged sidewalls forming an upwardly open structural member. Notches 43 are formed in one sidewall of housing 26 to receive a portion of an adjustable control for MAS system 29. The front of the housing 26 is formed of an upward facing U-shaped transverse flange 44 for receiving the transverse structural tube 45 (FIG. 8A), and the holes 46 (FIG. 11) form a generally adjacent flange. The transverse tube 45 is welded to the flange 44 and extends substantially horizontally. The reinforcement channel 47 is welded to the housing 26 near the front of the transverse structural tube 45. The frustoconical tube portion 48 is welded perpendicularly to the reinforcement 47 at the top of the hole 46, so that the tube portion 48 is firmly engageable with the upper end of the extendable central strut 42. Is formed. A pair of reinforced upwardly extending side arms 49 (sometimes referred to as “struts” or “pods”) are welded to opposite ends of the transverse tube 45. The side arms 49 each comprise a reinforcing plate 50 on the inner face of the arm. The plates 50 comprise a welding nut 51 which is aligned to define the backrest tilting axis 23. The housing 26, the transverse tube 45, and the side arms 49 form a rigid, rigid base frame. The sidewalls of the housing 26 include lips or flanges that extend along their upper edges to reinforce the sidewalls. The cap 52 is attached to the lip to form a fixed portion of the linear bearing that slidably supports the front of the seat.

Main energy apparatus and operation

The housings 26 shown in FIGS. 9-9C and 10 are slightly longer and have different ratios than the housings of FIGS. 8, 8A and 11, but the principle of operation is the same. The main energy device 27 (Fig. 8) is located in the housing 26. The main energy mechanism 27 includes a spring 28 operatively connected to the seat by an L-shaped torque member or bell crank 54, a link 55, and a seat attachment bracket 56. The spring 28 is a coil spring positioned transversely in the housing 26 with one end supported by the disk-shaped anchor 57 relative to the side of the housing 26. The anchor 57 includes a washer for supporting the end of the spring 28 to prevent noise, and extends into the center of the end of the spring 28 to firmly grasp the spring 28, but the spring 28 It further includes a protrusion that is compressed and inclined / bent toward the side to allow the torque member or bell crank 54 to pivot. The L-shaped torque member or bell crank 54 includes a short leg or lever 58 and a long leg 59. The short leg 58 has a free end that engages one end of the spring 28 near the left side of the housing 26 with a washer and protrusion similar to the anchor 57. The short leg 26 is arcuate and includes an outer surface facing an adjacent sidewall of the housing that defines a series of teeth 60. The steel strip 61 is attached to the upper and lower sides of the short leg 58 and has an outer arcuate face that provides a smooth rolling bearing face on the leg 58 as described below. The arcuate face of the strip 61 is generally located around the vertex or pitch diameter of the gear tooth 60. The short leg 58 extends generally perpendicular to the longitudinal direction of the spring 28, and the long leg 59 extends generally parallel to the length of the spring 28 but is spaced apart from the spring 28. The link 55 (Fig. 8) is pivoted about the end of the long leg 59 and also about the seat attachment bracket 56.

The crescent-shaped pivot member 63 (FIG. 11) includes an arcuate rolling bearing surface that rolls into engagement with the curved surface of the steel strip 61 on the short leg 58 to define the movement support point. The pivot member 63 is also provided with a tooth 64 formed to engage with the teeth 60 on the short leg 58 to prevent any slippage between the rolling bearing face of the leg 58 and the boundary of the pivot member 63. It also includes tooth support. Pivot member 63 is attached to the side of housing 26 at notch 43. When the seat 24 is in the rear position (ie when the backrest is in the upright position, Fig. 9), the long legs 59 are positioned substantially parallel to the spring 28 and the short legs 58 are The spring is pivoted to compress to a relatively low size. In this position, compression of the spring 28 is sufficient to adequately bias the seat backwards, and then biases the back frame 30 to an upright position to provide optimally comfortable support for the seated user. When the seated user is inclined, the seat 24 is moved forward (Fig. 9A). This causes the L-shaped torque member or bell crank 54 to roll on the pivot member 63 at the support point in a manner that compresses the spring 28. As a result, the spring 28 increases the force that resists the inclination, which is necessary for proper support as the user inclines. In particular, the spring leg 58 "moves" along the crescent shaped pivot member 63 a short distance while being tilted so that the actual pivot position changes slightly during the tilting. The gentle curved shape of the short leg 58 and the pivot member 63 prevents abrupt changes in the support for the backrest while tilting, but the curved shape of these two elements affects the spring compression in two ways. It should be noted that The " movement " of the short legs 58 on the pivot member 63 affects the length of the moment arm relative to the actual pivot point (i.e., where the teeth 60, 64 are engaged in time at a particular point). Further, the "movement" may cause the spring 28 to be compressed in the longitudinal direction as the "movement" occurs. However, in a good configuration, the system is designed so that the spring 28 is not significantly compressed during the adjustment of the pivot member 63 for reasons that adjustment should be easily achieved. If adjustment occurs by the spring 28 being compressed, adjustment will require additional effort to perform the adjustment, which is undesirable for the chair design of the present invention.             

As will be explained below, the pivot member 63 is adjustable to change the torque arm throughout the spring 28 operation. 9B shows the main energy mechanism 27 adjusted to the high torque position with the seat 24 in the rear position (and the back frame 30 in the upright position). FIG. 9C shows the main energy mechanism 27 in the compressed state with the seat 24 in the forward position (and the back frame 30 in the upright position), while still in the high torque state. In particular, in FIGS. 9B and 9C, the pivot member 63 has been adjusted to provide a long torque arm on the lever 58 throughout the spring 28.

9D is a graph showing the back torque generated by the spring 28 as a function of the angle of inclination. As will be clear from the graph, the initial force of the support can be changed by adjustment (as described below). In addition, the rate of change of the torsional force (i.e., the slope) changes automatically as the initial torsional force is adjusted to a higher force, so that the lower initial spring force exhibits a gentle slope while the high initial spring force exhibits a steep slope. This is an advantage because the light / small person needs less support in the upright position of the chair, as well as less support while inclining. Conversely, heavy / large people require greater support when in the upright and inclined positions. In particular, the required slope of the high and low torque force / displacement curves can be designed inside the chair by changing the shape of the short legs 58 and pivot member 63.

The crescent-shaped pivot member 63 (FIG. 11) is pivotally supported on the housing 26 by the bracket 65. As shown in FIG. The bracket 65 includes a tube portion 66 with a joint formed therein to engage the notch 43 within the side of the housing 26 and an end 67 of predetermined shape. The end portion 67 of the predetermined shape includes a pair of flanges 68 with openings defining the axis of rotation 69 for the pivot member 63. Pivot member 63 is pivoted about flange 68 by a pivot pin and is rotatable about axis 69. By rotating the pivot member 63, the engagement of the teeth 60, 64 and associated interfacing surfaces changes in such a way that the actual pivot point changes along the L-shaped torque member or the bell crank 54 (Figures 9 and 9). Comparison of 9b). As a result, the distance from the end of the spring 28 to the actual pivot point changes. This causes shortening (or lengthening) of the torque arm while the spring 28 is in operation, followed by a significant change in the force / displacement curve (compare the upper and lower curves of FIG. 9D). The change in the moment arm can be achieved relatively easily because the spring 28 is not compressed while being substantially adjusted, since the interfacing surface on the pivot member 63 defines a constant radius around its axis of rotation. Thus, the adjustment is not adversely affected by the strength of the spring 28. Nevertheless, the adjustment has a great influence on the spring curve as the spring 28 causes a change in the length of the moment arm during operation.

Pivoting the pivot member 63 is accomplished by using a flange 70 (FIG. 11) in which a pair of openings are formed on the pivot member 63 spaced from the axis 69. As shown in FIG. The adjusting rod 71 extends through the tube portion 66 into the end 67 of the predetermined shape and pivots about the flange 70 with the opening formed. The rod 71 includes a threaded opposing end 72. The long nut 73 is screwed onto the rod end 72. The nut 73 includes a washer 73 ′ that rotatably engages the end of the tube portion 66 and extends in the longitudinal direction in the form of an insertable engagement rib 75 engageable on the drive ring 76. Or an end portion 74 of a predetermined shape having a slot. The handle 77 is rotatably mounted on the tube portion 66 and is operably connected to the drive ring 76 by an overtorque clutch ring 78. Clutch ring 78 includes an elastic flange 79 that operatively engages a ring of friction teeth 80 on drive ring 76. Fingers 79 are formed to frictionally slide over teeth 80 at a torsional load that is preset to prevent damage to the elements of chair 20. Retention portion 81 includes an elastic leg 81 ′ that snaps to an end 74 of nut 73 to hold drive ring 76 and clutch ring 78 together at a pre-set amount of force. do. Spacer / washer 82 rests on the end of nut 73 to provide a bearing ring for best supporting clutch ring 78 for rotation. End cap 83 covers the end of the assembly so that it can be seen. The end cap 83 includes a central protrusion 84 that snaps into the retainer 81 to forcibly retain the resilient legs of the retainer 81 engaged within the end of the nut 73.

In use, adjustment is achieved by rotating the handle 77 on the tube portion 66, which means that the force required for the rotation of the nut 73 is not too large to prevent the clutch ring 78 from damaging the element. So that the nut 73 is rotated by the clutch ring 78 and the drive ring. When the nut 73 rotates, the rod 71 is pulled outward (or pressed inward) from the housing 26 to rotate the pivot member 63. The pivot of the pivot member 63 changes the engagement point (ie, support point) of the pivot member 63 and the L-shaped torque member or the short leg 58 of the bell crank 54, so that the spring 28 is in operation. Change the moment.

Backrest stop mechanism

The back rest stop mechanism 36 (FIG. 8) includes a cam 86 pivoted relative to the housing 26 in position 87. As shown in FIG. The cam 86 includes a stop surface or step 88, a stop depression 89 corresponding to the stop surface 88, and a tooth 90. The stepped portion 88 is formed to engage the seat attachment bracket 56 to limit the rearward rotation of the back frame 30 by limiting the rearward movement of the seat 24. This allows the seated user to limit the size of the slope to the maximum point required. The leaf spring 91 (FIG. 10) is attached to the housing 26 by using a U-shaped finger 92 that slides through the first hole and hooks into the second hole in the housing 26. As shown in FIG. The opposite end of the leaf spring includes a U-shaped bend 93 formed to slidably engage the stop depression 89. The depression 89 corresponds to the step 88 so that when the particular step 88 is selected, the corresponding depression 89 is engaged by the spring 91 so as to retain the cam at the selected angular position. In particular, the stepped portion 88 (and the recessed portion 89) are located at near angles together in an area corresponding to the chair position in the vicinity of the upright position of the backrest frame 30, corresponding to a more fully inclined chair position. It is located at a farther angle within the area. This allows the seated user to select from the maximum number of back rest positions when in the vicinity of the upright position. It should be noted that the seated user is likely to want multiple backrest stop positions that are close together when in the vicinity of the upright position, and less likely to select the backrest stop position near the fully inclined chair position.

Cam 86 rotates through the use of a control that includes pivot lever 94, link 95, and rotation handle 96. Pivot lever 94 is pivoted about midway relative to the housing in position 97. One end of the pivot lever 94 includes a tooth 98 that engages with the tooth 90 of the cam 86. The other end of the lever 94 is pivoted relative to the rigid link 95 at position 97 '. The handle 96 includes a body 101 rotatably mounted on the tube portion 66 of the MAS pivot bracket 65 and further includes a flipper 99 to easily wrap the seated user. The protrusion 100 extends from the body and pivotally attaches to the link 95.

To adjust the back stop mechanism 36, the handle 96 is rotated, which rotates the cam 86 through the operation of the link 95 and the lever 94. The cam 86 is rotated to the angular position required to engage the seat attachment bracket 56 such that the selected step 87 prevents any further inclination past the defined backrest stop. Since the seat 24 is attached to the backrest frame 30, this limits the inclination of the backrest 22.

A modified control for the operation of the backrest stop cam 86 is shown in Fig. 11A. The modified control includes a rotatable handle 96A and a pivot lever 94A connected to the handle 96A by a rotary pivot / slide joint 380. Lever 94A includes teeth 381 that engage cam 86 and are pivoted about housing 26 at pivot 97, all of which are similar to lever 94. However, in the modified control, the link 95 is removed and replaced with a single joint 380. Joint 380 includes balls 381 (FIG. 11B) extending from lever 94A. Snap-on "car" or bearing 382 includes a socket 383 for pivotally engaging ball 381 to define a ball-socket joint. The bearing 382 includes an outer surface 384 that slidably engages a slot 385 in the arm 386 extending radially on the handle 96A, FIG. 11C. The joint 380 is in contact with the lever 94A despite the combined movement resulting in the rotation of the handle 96A around the first axis and the rotation of the lever 94A around the second axis beveled about the first axis. Operatively connect the handle 96A. Advantageously, the deformed control is provided with parts inside the control housing 26, with little or no operatively interconnected parts, so that the parts are substantially in view of the person standing next to the chair. Invisible

Backrest structure

The back frame 30 and the back shell 31 (FIG. 12) form a flexible back support that is particularly comfortable and suitable for the movement of the user's back seated, especially within the lumbar region of the back 22. The adjustment feature for the assembly provides more comfort and allows the chair to meet the user's specific needs and preferences from the inclined position to the upright position.

The back frame 30 (FIG. 12A) is curved to form an arc across the back region of the chair 20. FIG. Various structures are contemplated for the back frame 30, and therefore, the present invention should not be unduly limited to only one particular shape. For example, the back frame 30 may be metal, plastic or a combination thereof as a whole. In addition, the internal rigid reinforcement 102 described below may be tubular, angle iron, or stamping. The illustrated backrest frame 30 includes an annular or arcuate inner metal reinforcement 102 and an outer molded polymer sheath or cover 103. [For illustration, the lid 103 is shown as transparent (FIG. 12A), so that the reinforcement 102 can be easily seen.] The metal reinforcement 102 has a circular cross section (only half in FIG. 12A). Only an annular intermediate rod portion 104). The reinforcement 102 is welded on the end of the intermediate portion 104 to include an end / bracket 105 of a predetermined shape. One or more T-shaped upper pivot connectors 107 are attached to the middle portion near the upper portion. In particular, the single top connector 107, when used, allows for more parallelism than the two top connectors, which would be desirable for a chair where the user frequently twists their upper body and leans to the side in the chair. The pair of spaced top connectors 107 provide a reinforced arrangement. Each connector 107 (FIG. 12B) includes a stem 108 welded to the intermediate portion 104 and includes a transverse rod portion 109 extending through the stem 108. The rod portion 109 is located out of the shell or shell 103 and pivotally engages with the engaging recess in the backrest shell to rotate about the horizontal axis, as will be described below. The present invention contemplates including different backrest frame shapes. For example, the inverted U-shaped intermediate portion 104 of the backrest frame 30 is an inverted T-shaped intermediate portion having a transverse member that is generally parallel and adjacent to the belt bracket 132 and extends upwardly therefrom. Can be replaced by In a preferred form, each back frame of the chair of the present invention defines a spaced bottom connection or opening 113 defining an upper connection 107 and pivot points forming a triangular arrangement. This arrangement is combined with the semi-rigid elastic backrest shell 31 to flexibly support the posture and allow torsional bending of the upper body of the seated user when in the chair. In another form, the lower connecting portion 113 may be formed on the seat instead of the back of the chair.

The shaped end 105 includes an inner surface 105 '(FIG. 13) that may or may not be covered by the outer shell 103. In the backrest frame 30 shown in Figs. 12A and 4A, the reinforcement 102 is substantially covered by the shell 103, but the pocket is inside the end portion 105 of the predetermined shape in the openings 111 to 113. It is formed on the face. The end portion 105 of the predetermined shape includes a protruding flange-forming opening 111-113 that subsequently defines a lower pivot connection for the backrest tilt axis 23, the seat tilt axis 25 and the backrest shell 31, respectively. . Openings 111 and 112 (FIG. 13) include truncated conical flanges 116 that define pockets for receiving multiple bearings 114 and 115, respectively. The bearing 114 includes an outer rubber bushing 117 that joins the inner lubricated bearing element 118 and the flange 116. The pivot stud 119 includes a second lubricated bearing element 120 slidably engages with the first bearing element 118. The stud 119 extends through the bearing 114 in the outward direction and is screwed into the nut 51 welded on the side arms 49 of the base frames 26, 45 and 49. The bearing element 118 touches the bottom on the nut 51 to prevent overtightening of the stud 119. The head of the stud 119 is formed to slide through the opening 111 to facilitate assembly by allowing studs to be screwed into the nut 51 from the inside of the side arm 49. It should be noted that the head of the stud 119 can be enlarged to passively capture the end 105 of the predetermined shape with respect to the side arm 49 if desired. The configuration of the present invention including the rubber bushing 117 allows the pivot 23 to bend to compensate for rotations that are not completely aligned with respect to the axis 23, thereby reducing the stress on the bearing and the stud 119 to the shaft. Stress is reduced on elements of the chair such as on the backrest frame 30 and the side arms 49 which are misaligned with each other.

The lower seat-back frame bearing 115 is similar to the bearing 114 in that the bearing 115 includes a rubber bushing 121 and a lubricating bearing element 122, but with the frustoconical face facing inward. It should be noted. The welded stud 123 extends from the seat carrier 124 and includes a lubricated bearing element 125 for rotationally and slidably engaging with the bearing element 122. In the arrangement shown, the shaped end 105 is captured between the side arms of the base frames 26, 45, and 49 and the seat carrier 124 such that the bearings 114, 115 have a shaped end 105. It should be noted that it is not necessary to be retained manually for. Nevertheless, the passive bearing arrangement can be easily configured on pivot 112 by expanding the head of stud 119 and by using a similar head stud in place of welded stud 123.

The second shape of the end of the predetermined shape of the backrest frame 30 is shown in Fig. 13A. Similar elements are denoted by the same reference numerals, and modified elements are denoted by the same reference numerals with the letter "A" added thereto. At the deformed end 105A, the frustoconical faces of the pivots 111A, 112A are directed in opposite directions from the pivots 111, 112. Pivot portion 112A (including welded studs 123A that pivotally supports seat carrier 124 on backrest frame 30) includes threaded axial holes in the outer end. Retention screw 300 extends into the threaded hole to securely hold the pivot assembly together. In particular, the washer 301 on the screw 300 engages and securely retains the bearing sleeve 125 mounting the inner bearing element 122 on the pivot stud 123A. The taper on the inside of the pocket and on the bearing outer sleeve 121 reliably holds the bearing 115A together. The upper pivot 111A pivotably supporting the backrest frame 30 on the side arm 50 of the base frame is the lower pivot (except in the case where the pivot 111A faces in the opposite inward direction). Generally the same as 112). In particular, in the upper pivot 111A, the stud 119A is welded on the side arm 50. The bearing is operably mounted on studs 119A in a bearing pocket defined within base frame 30 and held in place with screws 300 having other washers formed therein. For assembly, the back frame 30 is spaced apart and bent to engage the bearing 115, the end portion 105A of the predetermined shape is twisted and elastically bent, after which they are released to elastically return to the rest position. . This arrangement provides a fast assembly process that is secured and easily completed without fasteners.

The backrest shell system of the present invention shown in Figs. 12, 15 and 16 (and the backrest system shown in Figs. 12D-12I) is flexibly designed to operate in response to the user's back. The word "compliant" as used herein refers to the backrest of the present invention in lumbar region (see FIGS. 12 and 12F-12I) or back structure, which provides equivalence with flexibility (FIGS. 12D and 12E). The term "sympathetically" means that the backrest supports the seated user's back in detail when the chair back 22 is tilted and the seated user swivels their lower back. It means to move in close harmony with the seated user's back. The back shell 31 has three parts, such as a human's back having a thoracic region, a lumbar region and a pelvic region.

The thoracic "thorax", the region of the human back, is relatively rigid. For this reason, a relatively rigid upper shell portion (Figure 12) is provided that supports the relatively rigid chest (thoracic) region 252 of the seated user. This supports the weight of the user's upper body. The upper pivot axis is located in an important position just behind the user's average center of gravity, balancing the weight of the person's back for good pressure distribution.

The lumbar region 251 of the human back is more flexible. For this reason, the shell lumbar region of the backrest shell 31 includes two curved vertical action hinges 126 at the side edges (Fig. 15) connected by many horizontal "cross straps" 125 ''. . These straps 125 '' are separated by a widthwise slot 125 'that allows the strap to move independently. Slot 125 'may have a radial end or a teardrop-shaped end to reduce stress concentration. This shell region is formed for comfort and supports the human lumbar region in detail. The two side straps 125 ″ can bend and can significantly change the radius of curvature between the sides. The shell area automatically changes the curvature as the user's posture changes, but maintains a relatively constant level of support. This allows the user to consciously (or unconsciously) flex the back of the user while working temporarily while relieving the stress of tired muscles or different spinal disc portions. This frequent movement provides nutrients through the spine, providing "transportation" to help healthier. When a particular user leans against the shell 31, the user exerts a unique relative pressure on the various lumbar “cross straps”. This allows the working hinge to bend in a unique path and press to conform to the user's unique back shape. This provides more uniform support that increases comfort and reduces the "high pressure point" over most areas of the backrest. The transverse straps can be bent to better match the shape between the sides of the user. The neutral axis of the human spine is well positioned inside the backrest. Thus, the "side straps" are located in front of the central portion of the lumbar region (close to the spinal neutral axis), helping the flexure structure of the shell to resemble the flexion of the human back.

Pelvic region 250 is rather curved than human. Thus, the lowermost part of the shell 31 is not rather curved to support the posture of the human pelvis which is not flexed in a posture / combinable manner. When the user spins the spine backwards, the user's pelvis is automatically pivoted against the hips and skin upon stretching the user's back. The lower shell / back frame is located slightly rearward of the human hip but at a nearby point. This proximity allows the shell pelvic area to rotate in response to the user's pelvis. However, by being slightly rearward, the lumbar region of the shell is stretched slightly less than the skin of the user's back (enlarging of the slots) to be sufficient to be more responsive and bend, but not to stretch the fabric or create wrinkles in the fabric. Not as big as             

In particular, the backrest shell structure 31 (FIG. 4A) of the present invention comprises an elastically flexible molded sheet made from a polymer material such as polypropylene, with the upper and lower cushions positioned thereon (see FIG. 4A). do. The back shell 31 (FIG. 16) includes a plurality of horizontal slots 125 'in the lower half located in a generally lumbar region of the chair 20. FIG. Slot 125 ′ extends substantially across backrest shell 31, but the elastic vertical band 126 of material 126 terminates at a position spaced from the side to form along each edge. The band or side straps 126 of material naturally form forward convex shapes, but are flexible to provide optimal lumbar support and shape for the seated user. The band 126 allows the back shell to vary in shape to conform to the shape of the user's back, perpendicular to the sides in a flexible manner. The ridge 127 extends along the outer circumference of the shell 31. A pair of spaced recesses 128 are formed on the posterior surface of the upper chest region of the backrest shell 31. Recesses 128, 14A and 14B are formed in the narrow portion 129 of the upper connector 32 and the narrow portion 129 of the recess having a width to receive the stem 108 of the upper connector 32 on the back frame 30. Each comprising a T-shaped inlet with a wide portion 130 of a recess 128 having a width formed to receive the transverse rod portion 109. The recesses 128 oppose the rod portion 109 of the T-shaped upper connector 107 to form an adjacent narrow portion 129 when the stem 108 slides into the narrow portion 129. The flange 131 extends upwardly into the backrest shell 31 to pivotally capture. Ridge 132 in recess 128 securely holds the upper connector frictionally and secures the backrest shell 31 to the backrest frame 30, but the backrest shell 31 pivots about the horizontal axis. Allow it to be. This allows the backrest shell 31 to be undesirably restricted and to bend for optimal lumbar support.

Belt bracket 132 (FIG. 16) includes a long central strip or strap 133 that conforms to the shape of the bottom edge of backrest shell 31 and is molded into the bottom edge of backrest shell 31. As shown in FIG. The strip 133 may be an integral part of the back shell, or may be attached to the back shell 31 using screws, fasteners, adhesives, friction tabs, insert molding techniques, or any type of attachment technique known in the art. Can be attached. The strip 133 includes a side arm / flange 134 extending forward from the end of the strip 133 and including an opening 135. Torsion control lumbar spine mechanism 34 engages flange 134 and pivotally attaches backrest shell 31 to backrest frame at position 113 (FIG. 4A). The torsionally adjustable lumbar spring mechanism 34 is adjustable and biases the backrest shell 31 into a forward protruding shape to provide optimal lumbar support for the seated user. The torsionally adjustable lumbar spring mechanism 34 cooperates with the elastic flexibility of the backrest shell 31 and the shape change capability of the vertically adjustable lumbar support 35 to provide high flexibility and comfortable back support for the seated user.

The pivot position 113 is optimally selected slightly above the seat 24 at the rear of the sciatic arm (see Figure 12). Optimally, the front / rear distance from the pivot position 113 relative to the strip 133 is very similar in that the lower back 250 is moved in such a way that the lower back of the seated user moves while flexing against the hip joint of the seated user. It is approximately equal to the distance from the hip / axis of the user seated to move appropriately from the lower spine / tail region. The position 113 combined with the length of the side flange 133 extending forward causes the backrest shell 31 to bend accordingly in a suitable manner. The pelvic support area 250 of the back shell structure 31 corresponds to the user's spine and body movement when the seated user flexes their back and presses the lower part of the user's back against the back shell structure 31. Suitably to move backwards and downwards along the path selected. Lumbar support region 251 is simultaneously bent from a concave forward shape to a flatter shape. Chest support region 252 rotates with respect to upper connector 107 but does not flex to a significant size. The overall angular rotation of the pelvic and chest support regions 250, 252 is much larger than the synchronous tilting chairs of the prior art, which provide significantly increased support. In particular, the back shell structure 31 is also curved in the horizontal plane to provide good postural support for the user twisting the upper body to reach the target. In particular, the backrest frame 30 faces at an angle of about 5 ° from the vertical when in the upright position and rotates at a rear angle of about 30 ° from the vertical when in the fully inclined position. At the same time, the seat inclination shaft 25 is rearward at an angle of about 60 ° horizontally downward from the back inclination axis 23 when the backrest frame 30 is in an upright position, and the backrest frame 30 is inclined completely. Is pivoted to a nearly vertical bottom of the back tilting axis 23 when in position.

The backrest structures 31a-31f (FIGS. 12D-12I, respectively) are additional structures adapted to provide many aspects of a compatible backrest support for the backrest shell structure 31. Similar to the back structure 31, the present invention is intended to include attaching the back structure 31A to 31F to the seat or base frame at the lower connection. In particular, the illustrated structures 31A-31F are used in combination with the back frame 30 to provide specific support tailored to the thoracic, lumbar and pelvic regions of the seated user. Each back structure 31A-31F pivots at the upper and lower pivot connections 107, 113, and includes side arms 134 to be bent relative to the lever pivot axis 113 at a particular position.

The backrest structure 31A (FIG. 12D) includes a cushioning upper back support 255 pivoted at the upper pivot connection 107 and is in its lower position 113 by a belt bracket 132 including a side flange 134. It further includes a cushioning lower back support 256 that is pivoted. Upper and lower back support 255, 256 are joined by pivot / slide connections 257. Pivot / slide connection 257 includes a lower pocket defined by a pair of flanges 258 and an upper flange 259 that slides and pivots within the pocket. A torsional lumbar support spring mechanism 34 is attached to the lower pivot position 113 and, if desired, also attached to the connection 107 to bias the upper and lower back support 255, 256 forward. The combination provides a compatible backrest support that moves with the user's back selected to match the shape of any user's back, similar to the backrest shell structure 31 described above.

The backrest structure 31B (Fig. 12E) includes an upper back support 261 pivoted at the upper connection 107, a lower back support 262 pivoted at the lower connection 113 on the belt bracket side flange 134, and between them. And an intermediate back support 262 operatively connected to it. The intermediate back support 262 is pivoted relative to the lower back support 262 at the pivot 263 and slidably pivots relative to the upper back support 261 at the pivot / slide joint 264. Pivot / slide joint 264 is formed by an upper flange 265 defining a pocket, another flange 266 having ends pivoted and slid within the pocket. The spring is positioned in one or more joints 107, 113, and 264 to bias the back structure 260 in a forwardly concave shape.

The backrest structure 31C (FIG. 12F) is similar to the backrest shell structure 31 in that it includes a sheet-like flexible shell with transverse lumbar slit. The shell is pivoted against the backrest frame 30 at the upper and lower connections 107, 113. The shell of the backrest structure 31C is supported by the torsion spring mechanism 34 at the lower pivot 113 and the upper pivot 107, by the curved leaf spring 271 at the lumbar region of the shell, Forward by a spring 272 that pushes away forward of the middle portion of 30 and / or by a vertical spring 273 that extends from the upper connection 107 on the rear pivot on the belt bracket side flange 134. It is convenient in convex shape.

The backrest structure 31D (Fig. 12G) has a gap between the opposite sides of the backrest frame 30, and in the backrest structure 270 the lumbar region forward of the backrest shell 277, very similar to the spring 272. A transverse leaf spring 276 is provided for convenience. The backrest structure 31E (FIG. 12H) is a vertical leaf spring 279 fitted within the backrest shell 280 that biases the lumbar region of the backrest shell 280 forward, much like the spring 271 in the backrest structure 270. It includes. In particular, the back structure 278 includes only a single upper pivot connection 107. The backrest structure 31F (Fig. 12I) includes a vertical spring 282 connected to the belt bracket 132 at the top of the backrest frame 30 and at the bottom of the backrest shell 283. Because the backrest shell 283 is convex forward, the spring 282 biases the shell 283 into a more convex shape and thus provides additional lumbar support (spring 273 on backrest structure 31C of FIG. 12F). )).

The torsional lumbar spring mechanism 34 (FIG. 12J) may be designed in many different configurations, but it is contemplated to include at least one spring operably connected between the backrest frame 30 and the backrest shell 31. Optionally, the arrangement includes a tension adjustment device having a handle and a friction latch to provide tension adjustment. The springs rotatably bias the belt bracket 132 forward to define a front convex shape that is optimally suitable for lumbar support for the seated user with the back shell 31. By rotating the handle to different latch positions, the tension of the spring is adjusted to provide the optimum front lumbar force. When the seated user presses against the lumbar region of the backrest shell 31, the backrest shell 31 suitably moves and flexes to reflect the seated user's spine and body. The forces of the bands of the material 126 in the shell 31 provide a relatively constant force towards their natural curvilinear shape, but when combined with the torsional lumbar support spring mechanism 34, they cause the user to lean against the lumbar region. According to the lumbar support provides an easy to adjust convenience. It should be noted that a fixed, non-adjustable spring may be used directly to facilitate the backrest belt or the backshell flexion zone, or an adjustable spring may be used that can only be adjusted during installation. However, the adjustable device of the present invention allows for optimal adjustment to meet the various needs of the seated user. Thus, the user can take various good postures.

In the torsional lumbar support spring mechanism 34 (FIG. 12J) of the present invention, the belt bracket 132 extends inwardly from the backrest frame 30 through a hole 291 in the belt bracket side flange 134. Is pivoted relative to the back frame 30. Bushing 292 engages stud 290 to provide for smooth rotation, and retention portion 293 retains stud 290 in hole 291. Base 294 is screwed or welded to base frame 30 by screws 294 'and includes a protrusion 295 having a sun gear 296 and a protruding tip 297 on one end. The hub 298 includes a plate 299 with a sleeved boss 300 for receiving the protrusion 295. The boss 300 has a slot 301 for receiving the inner end 302 of the helical spring 303. The body of spring 303 wraps around protrusion 295 and terminates within hooked outer end 304. The hub 298 has a pair of axial studs 305 extending from the plate 299 in the direction of the opposing boss 300. A pair of piezoelectric planetary gears 306 are pivoted about the axial stud 305 in the pivot hole 307. The plurality of teeth 308 are arcuately positioned relative to the pivot hole 307 on the planetary gear 306 and the drive pin 309 is located at one end of the arch. Cup-shaped handle 310 is formed to cover gear 306, hub 298, spring 303, and base 294. The handle 310 includes a flat end panel 311 having a central hole 312 that rotatably engages with the protruding tip 297 of the base 294. A pair of opposing helical recesses or channels 313 are formed in the end panel 311. The recess 313 includes an elongate portion having an inner end 314, an outer end 315, and a plurality of detents or scallops 316 formed between the ends 314, 315. The recesses 313 releasably receive the drive pin 309. The hooked outer end 304 engages a finger 317 on the belt bracket 132, which extends through an arcuate slot 318 in the end portion 105 of the predetermined shape of the backrest frame 30. do.

The handle 310 is rotated to actuate the torsional lumbar support spring mechanism 34. This allows the recesses 313 to engage with the drive pin 309 on the planetary gear 306. The planetary gear 306 is interlocked with the sun gear 296 such that the planetary gear 306 is urged with the drive pin 309 inward (or outward) and the planetary gear 306 with each pivot / axis 305. Rotate with respect to sun gear 296 when pressurized to rotate. Then, when the planetary gear 306 is rotated, they pressurize the hub 298 to rotate. By the connection of the helical spring 303 and the hub 298, the helical spring 303 is wound tightly (or not wound). Thus, the tension of the spring 303 on the belt bracket 132 changes adjustable. The detent 316 engages the drive pin 309 with a sufficient frictional resistance to keep the spring 303 in the required tension. By this arrangement, the winding angle of the helical spring 303 is greater than the rotation angle of the handle 310.

In the deformed torsional lumbar support spring mechanism 34A (Fig. 12K), the base bracket 244A is attached to an end portion 105A of the predetermined shape of the backrest frame 30. The lever 306A and the driver 298A are operably mounted on the base bracket 244A to wind up the helical spring 303A when the handle 310A is rotated. In particular, base bracket 244A includes pivot pin 290 that pivotally engages a hole 291 in belt bracket 132. The second pin 317 extends through the arcuate slot 318 in the end portion 105A of the predetermined shape, and the slot 318 extends around the pivot pin 290 at a constant radius. The two pins 360, 361 extend opposite the pivot pin 290 from the base bracket 244A. The driver 298A has an opening 362 with an opening having a hole 363 to rotatably engage the central pin 360. End 362 includes an outer surface 364 having an internal slot for engaging the inner end 365 of helical spring 303A. The outer end 365 is hook shaped to securely engage the pin 317 on the belt bracket 132. Finger-shaped stud 366 extends laterally from outer end 367 of driver 298A.

Lever 306A includes a body having a hole 368 for pivotally engaging the pin 361 and a slot 369 extending arcuately around the hole 368. Pin 370 extends from lever 306A to engage helical cam slot 313A on the inner surface of cup-shaped handle 310A. Teeth 371 on lever 306A are positioned to engage studs 366 on driver 298A. A hole 372 on the handle 310A rotatably engages the pivot pin 360 on the base bracket 244A.

The handle 310A is rotatable between the storage force position (FIGS. 12L and 12L1) and the high tension position (FIGS. 12M and 12M1). In particular, when handle 310A is rotated, pin 370 rests on slot 313A, which rotates lever 306A around hole 368 and pivot pin 361. When lever 306A is rotated, teeth 371 engage pin 366 to rotate driver 298A around pin 360. Rotation of the driver 298A rotates the inner end 365 of the spring 303A, causing the spring 303A to swing (or unwind). The arrangement of the driver 298A, the lever 360A, and the handle 310A provides a mechanical advantage of about 4: 1, adjusting the helical spring 303A to the amount of adjustment force required on the handle 310A. Wind it up as much as possible. As shown, about 330 [deg.] Rotation of the handle 310A results in a spring tension adjustment winding of about 80 [deg.].

Optionally, for maximum control, the vertically adjustable lumbar spine system 35 (FIG. 16) includes a side frame 150 (FIG. 19) that is generally flat and includes several hooked tabs 151 on the front face. Is provided. Concave lumbar support sheet 152 (FIG. 16) of a flexible material, such as spring steel, includes a plurality of vertical slots forming elastic plate spring-like fingers 153 along upper and lower edges of sheet 152. The (optional) height adjustable backrest support sheet 152 is basically a radial sheet spring, which can deflect until it conforms to the shape of the backrest shell at the bottom thereof with normal backrest support pressure. This provides a high force band across the backrest. This provides the user with a height adjustable local back support, regardless of the user's back flexure. This provides the advantage of traditional lumbar height adjustment without forcing the user to a specific rigid back posture. In addition, the fabric or inner material of the backrest is always kept well organized to eliminate wrinkles. Elongated fabrics can also be used to remove wrinkles.

The user may also use the device for a second reason that the user's own unique back shape should be fully adapted to the back shell shape. In particular, in the lower lumbar / pelvic region, a human can fantastically change the shape of the back. A user with a more extreme shape may benefit from sliding the device into an area where their back is not in fixed contact with the shell. The device will provide good support in this area and effectively change the shape to accurately "fill the gap". No other known lumbar height adjuster has the manner described below.

The four tips 154 on the finger 153 form a retaining tab adapted to securely engage the hooked tab 151 to retain the sheet 152 relative to the slide frame 150. The remaining tip 155 of the finger 153 slidably engages the slide frame 150 and holds a central portion 156 of the sheet recessed forward away from the slide frame 150. The slide frame 150 can be adjusted vertically on the backrest shell 31 (FIG. 16) and is located on the backrest shell 31 between the backrest shell 31 and the backrest cushion. Alternatively, the slide frame 150 may also be located between the backrest cushion and the lower part of the inner material covering the backrests 22 or on the front face of the backrest 22 outside the inner material sheet covering the backrest 22. . By adjusting the slide vertically, the arrangement allows the seated user to adjust the shape of the lumbar region on the backrest shell 31, thus providing a high degree of comfort. Laterally extending guides 157 (FIG. 19) are formed at each end of the slide frame 150. As shown in FIG. Guide portion 157 includes opposing flange 158 forming a groove facing inwardly. Shaped handles 159 (FIG. 20) include legs 160 formed to insertably engage guides 157, 17 and 18, respectively. The handle 159 further includes a C-shaped lip 160 configured to slide along the edge ridge 127 along the edge of the backrest shell 31 and snap-fit. It is contemplated that other means may be provided for guiding the vertical movement of the slide frame 150 on the back shell 31, such as a cord, along the inside of the edge of the back shell while track forming along the back shell. The long flat end portion 161 of the handle 159 extends laterally outward from the shaped handle 159. In particular, because the end portion 161 is relatively thin at the outwardly adjacent position 161 ′ of the lip 160, the handle 159 is a backrest 22 when the cushion and the inner material sheet are attached to the backrest shell 31. Along the side edges of the shell).

The illustrated backrest 22 of FIG. 12 includes a novel structure incorporating the sewn stretched fabric in position relative to the lower edge of the inner material sheet 402 to cover the front of the backrest 22. The stretched fabric 400 is further sewn into the notch 406 in the protrusion 403 of structural plastic such as polypropylene or polyethylene. The protrusion 403 is attached to the lower portion 404 of the backrest shell 31 by fastening means such as snap fastening attachment, hooked attachment, rivets, screws, other mechanical fasteners or other fastening attachment means. The foam cushion 405 of the backrest 22 and the vertically adjustable lumbar support device 35 are positioned between the sheet 402 and the backrest shell 31. It is contemplated that the stretched fabric has a recovery rate of at least about 100%, with a recovery rate of at least 90% or more. The stretched fabric 400 and the sheet 402 are sewn on the backrest 22 in the tensioned state so that the sheet 402 does not wrinkle despite the large curvature of the lumbar region 251 towards the planar state. The stretched fabric 400 is in an invisible position, but can be matched to the color of the chair if desired. It should be noted that the cover 402 extends to cover the front as well as the rear of the backrest 22.

Main seat movement, seat substructure / support frame and bearing arrangement

The seat 24 (FIG. 4B) is supported by an undercarriage comprising a seat front slide 162 and a seat carrier 124. As shown in FIG. If seat depth adjustment is desired, a manual depth adjustable seat frame 163 is slidably positioned on the seat carrier 124 (see FIGS. 4B and 21-30). If seat depth adjustment is not required, the elements of the seat frame 163 and the seat rear carrier 124 may be incorporated into a single element as shown in FIG. 29 by the frame member 163 ′. The seat shell 164 (FIG. 4B) includes a buttock supporting rear portion 165 located on the seat carrier 124. The buttock supporting rear portion 165 supports most of the weight of the seated user, and in this respect acts somewhat similar to the seat. The seat shell 164 further includes a thigh support front portion 166 extending forward of the seat frame 163. The front portion 166 is connected to the rear portion 165 by an elastic portion 167 located at a position slightly forward and below the hip joint of the seated user. The elastic portion 167 has a plurality of transverse slots therein. Slot 168 staggers relatively short across seat shell 164, but is spaced from the edge of the seat shell so that the band of material 169 remains idle and uninterrupted at the edge of seat shell 164. have. Band 169 firmly connects front and rear portions 166, 165 together and biases them toward a planar state. The seat cushion 170 is positioned on the seat frame 163 and held in place by an inner material sheet and / or a binder or the like.

Slide 162 (FIG. 4B) includes top panel 171 with C-shaped side flanges 172 extending downward and inward. A linear lubrication cap 173 is attached to the top of each sidewall of the housing 26, and a coupling bearing 174 is attached to the inside of the C-shaped side flange 172 to slidably engage the lubrication cap 173. In this manner, the slide 162 is captured on the housing 26 for forward and backward slide movement. The seat attachment bracket 56 is attached to the bottom of the upper panel 171 and is positioned to operate with the backrest stop mechanism 36. Axle 174 ′ is attached to apex of top panel 171 and includes an end 175 extending laterally from slide 162.

The sheet carrier 124 (FIG. 4B) is T-shaped in plan view. The seat carrier 124 is stamped T-shaped from the sheet metal and includes a relatively wide rear portion 176 and a narrow front portion 177. Embossed portions, such as long embossed portions 178, 179, and 180, form portions 176, 177 with side down flange 181 and side up flange 182 to reinforce the element. Two spaced stop tabs 183 and a series of latch openings 184 are formed in the front portion 177 for reasons to be described below. The welded stud 123 is attached to the side upward flange 182 and extends laterally. As mentioned above, the stud 123 defines the seat tilt axis at this position.

The seat frame 163 (FIG. 4B) is T-shaped very similar to the seat carrier 124, but the seat frame 163 is more similar in shape to a fan and to better support the seat shell 164 and seat cushion 170. Larger than the sheet carrier 124. The seat frame 163 includes a front portion 185 and a rear portion 186. The front portion 185 includes a top panel 187 having a downward flange 188 at the side. The hole 189 in front of the downward flange 188 forms a pivot axis for the active femoral flexion device 190 as will be described below. Another hole 191 spaced to the rear of the hole 189 supports the laterally extending axis and supports the multi-function control unit 192 to control the seat depth adjustment and the active thigh flexure device 190. The center of the front portion 185 is raised and defines a sidewall 193 (FIG. 23) having three holes 194-196 that cooperate to pivotally and operatively support the depth latch 197. The depression 198 is formed at the center of the front portion 185, and the slot 200 is cut out at the center of the depression 198. The T-shaped stop limiter 199 (FIG. 26) is located within the depression 198, with the stem 201 of the limiter 199 extending downward through the slots 200, 26 and 26A. It is screwed inside. The inverted U-shaped bracket 203 is attached to the wide rear portion 176. The U-shaped bracket 203 (FIG. 28) includes an opening for pivotably supporting one end of the gas spring 204 used in the active thigh flexion support device 190 to be described below. The rear portion 176 (FIG. 23) includes a U-shaped channel portion 205 extending around the outer and outermost outer flanges 206, which serve to reinforce the rear portion 176. As shown in FIG. A flat region 205 ′ is formed on the opposite side of the rear portion 176 to slidably engage the top of the rear bearing 209.

Seat Depth Adjustment

A pair of parallel elongated brackets 207 (FIG. 4B) is located below the outer side extending forward of the U-shaped channel portion 205 to slidably support the seat frame 163 on the seat carrier 124. FIG. Attached. The long Z-shaped bracket 207 forms an inwardly facing C-shaped guide or track (FIG. 21) extending below and below the seat frame 163. As shown in FIG. The bearing member is attached inside the guide of the bracket 207 to provide smooth operation if required. Two spaced front bearings 208 (FIG. 4B) and two spaced rear bearings 209 are attached to the apex of the seat carrier 124, and the front bearing 208 is attached to the front portion 177, the rear Bearing 209 is attached to rear portion 176. The rear bearing 209 is formed to slidably engage a guide in the bracket 207 and further includes a tongue 210 extending inwardly inside the C-shaped portion of the C-shaped guide. The tongue 210 captures the seat frame 163 so that the seat frame 163 is not pulled upward away from the seat carrier 124. The front bearing 208 slidably engages with the lower side of the front portion 187 in a spaced position. The front bearing 208 may also be made to capture the front portion of the seat frame 163, but it is not considered necessary because of the femoral flexion device that provides the function.

The depth adjustment of the seat 24 is performed manually on the bearings 208, 209 on the seat carrier 124 between the rear position for the minimum seat depth (see FIG. 24) and the front position for the maximum seat depth (see FIG. 25). Provided by the slide seat frame 163. The stem 210 of FIG. 199 (FIG. 26A) engages the stop tab 183 in the seat carrier 124 to prevent the seat 24 from being adjusted too far forward or too far backward. Depth latch 197 (FIG. 23) is T-shaped and includes pivot tabs 212, 212 ′ on one of the arms pivotably engaging openings 194, 195 in seat frame 163. Depth latch 197 is downward on other arms extending through opening 195 in seat frame 163 into a selected one of a series of slots 214 (FIG. 26) in seat carrier 124. It further includes an extended latch tooth 213. A “stem” of depth latch 197 (FIG. 23) extends laterally outward and includes an actuation tab 215. Multi-function control unit 192 includes an internal axis 217 that supports the main elements of the multi-function control unit. One of these elements is an inner sleeve 218 rotatably mounted on an axis 217. The handle 219 is connected to the outer end of the inner sleeve 218, and the protrusion 220 is connected to the inner end of the inner sleeve 218. The protrusion 220 is connected to the actuating tab 215 so that the rotation of the handle 219 moves the protrusion 220 and latches 197 relative to the latch pivots 194, 195 with the up and down disconnects. Pivot This releases the latch tooth 213 from the series of slots 214 so that the seat 24 can be adjusted to the new depth required. The spring on the inner sleeve 218 biases the latch 197 to its normal engagement position. It is contemplated that a variety of different spring arrangements can be used by including inner springs operably connected to inner sleeve 218 or latch 197.

Seat active thigh angle adjustment (with endless adjustable gas spring)

Anterior reinforcement plate 222 (FIG. 28) is attached to the lower side of thigh support front portion 166 of seat shell 164. The Z-shaped bracket 221 is attached to the plate 222, and the bushing 223 is fixed between the bracket 221 and the plate 222. The curved rod shaft 224 is rotatably supported in the bushing 223 and is end portion 225 pivotally supported in and extending through the opening 190 of the downward flange 189 of the seat frame 163. , 226). The end portion 226 includes a flat side, and the U-shaped bracket 227 is non-rotationally attached to the end portion 226 to support the end of the gas spring 204. The U-shaped bracket 227 faces the angle at a portion of the curved rod shaft 224 extending toward the bushing 223 so that the U-shaped bracket 227 seats the shell when the gas spring 204 is extended or retracted. Acts as a crank to raise and lower the femoral support front portion 166 of 164. In particular, the gas spring 204 is operably mounted between the brackets 227 and 203 to move the anterior thigh support portion 166 of the seat shell 164 upward to provide additional thigh support when extended. . In particular, the thigh support portion 166 provides some curvature even when the gas spring 204 is fixed in a fixed size, so that the thigh of the user is always comfortably supported. Nevertheless, the infinite adjustability of the actuation support system provides an improved adjustability which is very useful, especially for short legged people.

The gas spring 204 (FIG. 28) includes a release button 233 at the rear end attached to the bracket 203 to release the gas spring 204 so that the self-locking and extendable rod can be extended or retracted. . Such a gas spring 204 is well known in the art. The multi-function control unit 192 (FIG. 3) includes an actuator for operating the release button 233. FIG. In particular, the multi-function control unit 192 includes a rotatable outer sleeve 229 (FIG. 23) operatively positioned on the inner sleeve 218 and a handle 230 for rotating the outer sleeve 229. The connector 231 extends radially from an end into the interior of the outer sleeve 229. Cable 232 extends from connector 231 on outer sleeve 229 to release button 233 (FIG. 28). The cable 232 has a predetermined length selected to pull the release button 233 so that the cable 232 releases the internal lock of the gas spring 204 when the outer sleeve 229 is rotated. The release button 233 is spring biased to its normal locked position. The seated user adjusts the active thigh flexion support system by operating the handle 230 to release the gas spring 204. The seated user is then pressed on (or raised their legs away from) the thigh support front portion 166 of the seat shell 164, so that the gas spring 230 reattaches the thigh support front portion 166. Operate the curved rod shaft 217 to adjust. In particular, the working thigh support system 190 is provided for infinite adjustment within a predetermined adjustment range.

A second rotatable handle 234 operatively connected to the pneumatic vertical height adjustment mechanism for adjusting chair height by Bowden cable 235, sleeve 235 'and side brackets 235 " 192, FIG. 19 is shown. Details of the chair height adjustment mechanism are well known and need not be described herein.

The seat shell 164 and the support structure (FIG. 4B) are formed to support the thigh of the seated user. For this reason, the seat cushion 170 includes an indentation 170A positioned slightly forward of the hip joint of the seated user (Figure 12). The inner material covering the seat cushion 170B includes a tuck or fold at the indentation 170A so that the material expands or expands while the thigh support region is bent downward, which means that the top surface of the inner material cover This is because the fact that they are spaced above the bending hinge axis of the seat shell 164 causes expansion or expansion at the indentation. Alternatively, expanded or separate front and rear inner material cushions may be used.

Seat manual / flexible thigh support (without gas spring)

The passive thigh flexure device 237 (FIG. 30) includes a reinforcement plate 238 attached to the lower side of the thigh support front portion 166 of the seat shell 164 (FIG. 4B). The pair of L-shaped stop tabs 239 (Fig. 29) are bent downward from the body of the plate 238. The L-shaped tab 239 includes a horizontal finger 240 extending rearward to a position where the finger 240 overlaps the front edge 241 of the seat frame 163. Bushing 242 is located inside L-shaped tab 239 and includes notch 243 that engages front edge 241. The curved leaf spring 244 is positioned transversely below the reinforcement plate 238 with the end 245 of the leaf spring 244 engaging the recesses at the top of the bushing 242. The leaf spring 244 has a curved shape so as to be in a compressed state in the manual thigh flexure device 237 of the present invention. When the seated user presses down on the thigh support front portion 166 with their thighs, the leaf spring 244 moves the reinforcement plate 238 toward the front edge 241 of the seat frame 163. Bent in the center When this operation occurs, the fingers 240 move away from their respective bushings 242 (FIG. 31). When the seated user is depressurized downward on the femoral support anterior portion 166, the spring 244 flexes toward the neutral flexure shape to move the bushing 242 back in engagement with the finger 240 (FIG. 30). do. In particular, this manual thigh flexion device 237 allows the user to bend the sides of the thigh support front portion 166 of the seat shell 164 independently or continuously. The degree of bending of the manual thigh flexure device 237 is limited by the distance the bushing 242 can move within the L-shaped tab 239.

In the foregoing description, those skilled in the art will readily understand that modifications may be made to the present invention without departing from the concepts disclosed herein. Such modifications should be considered as included within the scope of the following claims unless the scope of the claims is expressed otherwise in their language.

Claims (240)

A base assembly having a control housing having opposing side flanges and side pivots positioned proximate to one of said side flanges; A backrest pivoted relative to the base assembly to move between an upright position and an inclined position, A seat operably supported on the base assembly and coupled to the backrest to synchronously move with the backrest; An energy appliance for biasing the backrest toward the upright position, The energy mechanism comprises an extension / compression spring positioned transversely in the control housing with one end supported on one of the side flanges, and a lever pivoted against the side pivot, The lever has a spring engaging portion engaging with the free end of the spring, and a seat convenience portion operatively connected to the seat, The side pivot, the spring coupling and the seat convenience are spaced apart from each other, and they are also arranged to bias the lever about a support point located on the side pivot to spring bias the backrest toward the upright position,  And the side pivot comprises an adjustable pivot member configured to change the position of the support point on the lever when adjusted. delete The chair of claim 1 wherein the pivot member and the lever comprise interfacing surfaces, wherein at least one of the interfacing surfaces is curved. 4. A chair as claimed in claim 3, wherein the interfacing surfaces comprise interlocking teeth. 5. A chair according to claim 4, wherein the lever comprises an L-shaped bell crank and the support point is located along the middle of one leg of the L-shaped bell crank. The chair of claim 1 wherein the lever and pivot member are pivoted about the vertical axes and moveable within a common horizontal plane so as to be intensively disposed in the control housing. 2. A chair according to claim 1, wherein the spring is supported by the control housing and engages the lever in such a way as to move the free end of the spring toward the supported end and simultaneously move along the front and rear direction during the inclination of the backrest. . A base assembly having a control housing having opposing side flanges and side pivots positioned proximate to one of said side flanges; A backrest pivoted relative to the base assembly to move between an upright position and an inclined position, A seat operably supported on the base assembly and coupled to the backrest to synchronously move with the backrest; An energy appliance for biasing the backrest toward the upright position, The energy mechanism comprises an extension / compression spring positioned transversely in the control housing with one end supported on one of the side flanges, and a lever pivoted against the side pivot, The lever has a spring engaging portion engaging with the free end of the spring, and a seat convenience portion operatively connected to the seat, The side pivot, the spring coupling and the seat convenience are spaced apart from each other, and they are also arranged to bias the lever about a support point located on the side pivot to spring bias the backrest toward the upright position, The spring is supported by the control housing and engaged with the lever in a configuration that moves the free end of the spring toward the supported end and simultaneously moves along the front and rear direction during the inclination of the backrest, The lever not only compresses the spring in the longitudinal direction, but also the spring flexes laterally in a non-linear manner during the inclination of the backrest. A chair comprising a control housing having a pivot member, a tiltable back operatively connected to the control housing to move between an upright position and an inclined position, and a source of energy within the control housing to bias the backrest toward the upright position, The adjustable back tension control unit includes a lever that engages the energy source and the adjustable pivot member, The lever is operably connected to the backrest to bias the backrest toward the upright position, the lever and the pivot member have non-slip interfacing surfaces, at least one of the interfacing surfaces being curved such that the interfacing surfaces are inclined during the inclination of the backrest. And the lever engages to define a moving support point when the lever is rotated, the support point being changed as the pivot member is adjusted to change the moment arm at which the energy source acts. 10. A chair as claimed in claim 9, wherein the lever comprises a bell crank having a leg pivotally engages in an intermediate position with the pivot member to define a support point. 11. A chair as claimed in claim 10, wherein the lever is pivoted in a horizontal plane about a vertical axis to be intensively disposed in the control housing. 12. The chair as claimed in claim 11, wherein the chair further comprises a link and a seat joining bracket operably connected to the lever by the link, wherein the lever biases the seat joining bracket and the seat rearward. The pivot member of claim 10, wherein the pivot member is pivoted relative to the control housing at a pivot position spaced apart from the interfacing surface of the pivot member, the interfacing surface of the pivot member being arcuate to define a constant radius from the pivot position. chair. 14. The chair of claim 13 wherein the interfacing surfaces have engaging teeth. 15. The chair as claimed in claim 14, wherein the interfacing surface of the lever also has a curved shape. 10. The chair as claimed in claim 9, comprising an adjustment mechanism for angle adjusting the pivot member to change the length of the moment arm. 17. The chair as claimed in claim 16, wherein the adjustment mechanism includes an overtorque device that prevents excessive torque from being applied by the user when the pivot member is adjusted. 10. A chair as claimed in claim 9, comprising a seat operably positioned on the control housing and interconnected between the lever and the backrest. The chair of claim 9 wherein the interfacing surfaces have engaging teeth. Base assembly, An element having one of a movable seat and an inclined backrest pivoted relative to the base assembly to move between the first position and the second position; One end supported by the base assembly and the other end operatively connected to the element, the spring having a predetermined length, Said spring being longitudinally compressed along said length as said element is moved from said first position to said second position and at the same time bending laterally laterally relative to said length. 21. A chair as claimed in claim 20, comprising a lever having a first end in contact with the other end of the spring and a second end linked to the element. The chair of claim 21 wherein the lever is pivoted relative to the base assembly. 23. The chair as claimed in claim 22, wherein said element comprises a movable seat. 24. The chair as claimed in claim 23, comprising a back frame operably connected to the seat to move simultaneously with the seat. A base assembly having a control housing; A seat slidably supported on the control housing, A backrest frame pivoted relative to the base assembly to move between an upright position and an inclined position and operably attached to the seat such that pivotal movement of the backrest frame and sliding movement of the seat are synchronized; An energy mechanism having a spring having a predetermined length and an L-shaped torque member, The L-shaped torque member has a first leg that engages with one end of the spring and a second leg that extends generally parallel to the length of the spring, The first leg is pivotally coupled to the control housing in a position spaced from the end of the spring, and the second leg is operably connected to one of the seat and back frame, to bias the back frame towards the upright position. A chair, wherein the spring biases the torque member. 27. The chair of claim 25, wherein the first leg includes a curved surface that rolls and pivotably engages the structure on the control housing as the back frame moves between an upright position and an inclined position. 27. The structure of claim 26, wherein the structure on the control housing includes a pivot member having an interface surface that engages a curved surface on the first leg, the surfaces configured to securely engage to prevent unwanted slippage. chair. A base assembly having a control housing; A seat slidably supported on the control housing, A backrest frame pivoted relative to the base assembly to move between an upright position and an inclined position and operably attached to the seat such that pivotal movement of the backrest frame and sliding movement of the seat are synchronized; An adjustable energy mechanism operably located in a relatively thin, horizontally extending compartment defined below the seat by the control housing, The adjustable energy mechanism includes an adjustable pivot support for resiliently controlling a stretchable energy source, a lever operably connected between the energy source and the seat, and a force controllably controlling the force transmitted from the energy source to the seat through the lever. Including an adjustment member, And the energy source, the lever and the adjustment member are movable only in the horizontal direction to operate in a relatively thin and horizontally extending compartment. 29. A chair as claimed in claim 28, wherein the adjustment member comprises a pivot member operably attached to the control housing for moving the lever to adjust the support point of the lever. delete delete delete delete delete The chair of claim 1 wherein the base assembly comprises a base frame incorporating a housing. 21. The chair as claimed in claim 20, wherein the base assembly comprises a base frame incorporating the housing. 27. The chair as claimed in claim 25, wherein the base assembly comprises a base frame incorporating the housing. The chair of claim 28 wherein the base assembly comprises a base frame incorporating the housing. delete delete A base assembly having a control housing; A single stored energy source located within the control housing to provide a compressive force, A backrest support operatively interconnected with said single stored energy source to move between an upright position and an inclined position, A controller, The single stored energy source applies a preliminary tension to bias the backrest support toward the upright position, while at the same time providing resistance to the inclination of the backrest support, The controller adjusts the preliminary tension of the stored energy source and the tilt ratio of the back support, and the controller includes a lever defining an adjustable support point that can be adjusted without overcoming the compressive force of the single stored energy source. Chair. 42. The chair of claim 41, comprising a seat coupled with the back support to interconnect the back support to the energy source. delete delete delete Base assembly, A seat supported on the base assembly, A backrest frame pivoted relative to the base assembly to move between an upright position and an inclined operating position; A flexible backrest connected to the back frame at at least one upper connection and connected to the chair at a lower connection vertically spaced from the at least one upper connection, The lower linkage is located in front of the bottom of the flexible back and near the rear of the seat to define an axis that is aligned with the area associated with the sciatic and lower vertebrae of the user in which the lower linkage is seated, The flexible back may be bent to receive a controlled bend between the upper and lower connections when the back of the seated adult user is bent, And the seat has a front part slidably supported on the base assembly and a rear part pivotally connected to the back frame, wherein the seat moves forward in synchronization with the back frame during the inclination of the back frame. 47. The backrest of claim 46, wherein the flexible back includes an upper section and a lower section operably connected to each other for reverse rotational movement, the upper section pivoting relative to the back frame at the upper connection, and the lower section at the back connection at the lower connection And an anterior extension flange pivoted about, wherein the rearward distance from the lower connection to the lower anterior surface of the lower section is determined from the hip joint of the average seated adult user to the posterior / lower vertebra of the average seated user. Roughly equal to the distance, the chair is characterized in that the flexible back flexes upon bending of the lower portion of the seated adult user's back while providing comfortable postural support. 47. The chair of claim 46, wherein the flexible back comprises a back shell having upper and lower rigid sections connected by a flexible zone located in the lumbar region of a seated adult user. 49. The chair according to claim 48, wherein the flexible zone includes a plurality of horizontal slits extending across the flexible back but terminating to leave a continuous band of material at opposite side edges of the lumbar region. 50. The chair of claim 49, wherein the chair comprises a torsional lumbar support mechanism operably attached to the backrest shell, wherein the torsional lumbar support mechanism biases the backrest shell into a convex shape projecting forward for optimal lumbar support. Chair. 51. The chair of claim 50, comprising a vertically adjustable lumbar support attached to the flexible back for vertical adjustment of the shape of the front face of the flexible back in the lumbar region of the seated user. 52. The vertically adjustable lumbar support of claim 51, wherein the vertically adjustable lumbar support includes a handle configured laterally extending along the edge to engage the outer peripheral edge of the flexible back, the handle having and following the peripheral edge of the handle. And slidably engages with a vertically adjustable lumbar support to adjust it out of condition. 47. The chair of claim 46, comprising a torsional lumbar support mechanism attached to one of the lower connections to bias the flexible back toward the convex shape projecting forward. 47. The chair of claim 46, wherein the chair comprises a vertically adjustable lumbar support operably attached to the front face of the flexible back, wherein the vertically adjustable lumbar support is a front face of the flexible back of the lumbar region of the seated user. Chair characterized in that it is configured to change the bearing capacity in the. 55. The chair of claim 54, wherein the chair comprises at least one handle slidably coupled in a horizontal direction with the vertically adjustable lumbar support, wherein the handle is at the outer edge of the flexible back to vertically adjust the vertically adjustable lumbar support Chair characterized in that configured to follow along. 49. The chair as claimed in claim 46, wherein the upper connection comprises an upper pivot connection. 59. The connector of claim 56, wherein the upper pivot connection includes a T-shaped protruding connector on the backrest frame and a mating recess in the flexible backrest, the recess receiving the T-shaped protruding connector to attach the flexible backrest to the backrest frame. The chair, characterized in that configured to frictionally engage. 47. The chair of claim 46, wherein the flexible back includes a belt bracket attached along the lower edge of the flexible back, wherein the belt bracket includes a flange that forms part of the lower connections. 59. The chair of claim 58 including an adjustable torsional lumbar support mechanism attached to one of the lower connections. 47. The chair as claimed in claim 46, wherein the back frame forms an inverted curved arch. 47. The chair as claimed in claim 46, wherein the back frame comprises an inner metal reinforcement and an outer polymer sheath covering all sides of the middle section of the metal reinforcement. 47. The backrest frame of claim 46, wherein the backrest frame includes ends of a predetermined shape located on opposite sides of the back of the seat, the ends of the predetermined shape pivoting to the seat and the first pivot for pivotal connection to the backrest frame. And a second pivot for forming the chair. Base assembly, A backrest frame pivoted relative to the base assembly to move between an upright position and an inclined operating position; A flexible back operatively attached to the back frame at the upper connection and operably attached to the chair at the lower connection, The flexible back includes a front protruding flange located along its lower edge forming a rotation axis at the lower connection, the rotation axis being located in front of the flexible back and near the rear section of the seat, the flexible back being the chest Part, pelvic part, and flexion lumbar spine, and when the seated user flexes the lower part of the back, the pelvic part of the flexible back pivots downward and backward about the axis of rotation, The vertebral portion flexes backwards to be more planarly aligned with the pelvis portion and the chest portion of the backrest is configured to pivot about the upper connection, such that the flexible back rests with the seated user's torso and Providing postural support for the seated back of a seated user that flexes and moves the spine. Chair according to claim. 64. The chair of claim 63, comprising an adjustable torsional lumbar support spring mechanism that biases the flexible back into a forward protruding convex shape for optimal lumbar support for the seated user. 65. The chair of claim 64, wherein the flexible back comprises a molded shell having an elastic lumbar section. 66. The chair as claimed in claim 65 comprising a belt bracket attached to the lower edge of the shaping shell. 67. The chair of claim 66, comprising a vertically adjustable lumbar support operably attached to the front of the flexible back. 64. The chair of claim 63, wherein the upper connection comprises a protrusion on the base frame and a coupling recess on the flexible back, the recess configured to receive the protrusion and to frictionally engage the protrusion. 65. The chair of claim 63, comprising a vertically adjustable lumbar support attached to the flexible back in the lumbar region to alter the shape of the front face of the flexible back in the lumbar region of the seated user. 70. The chair of claim 69, comprising a handle operatively coupled with the vertically adjustable lumbar support and configured to follow the outer periphery of the flexible back during vertical adjustment of the vertically adjustable lumbar support. 66. The backrest frame of claim 63, wherein the backrest frame has an end of a predetermined shape located on opposite sides of the flexible backrest, the end of the predetermined shape having a backrest tilt axis, a seat tilt axis, a backrest tilt axis, and a seat tilt. A backrest shell lower inclination axis positioned rearward of the axle, the backshell shell inclination axis being positioned in an adjustable torsional lumbar support spring mechanism. 66. The flexible backrest of claim 63, wherein the flexible back comprises a coated sheet, wherein at least the extensible portion of the coated sheet is of an extensible material that holds the coated sheet in tension on the flexible back during bending of the flexible back. Chair. 73. The chair as claimed in claim 72, wherein the stretchable portion comprises a strip of stretch fabric sewn to the bottom edge of the sheath sheet. 74. The chair of claim 73, wherein the flexible back includes a back shell and a protrusion attached to a strip of stretch fabric, the protrusion being secured to a lower edge of the back shell. 75. The chair of claim 74, wherein the protrusion comprises a notch receiving an edge of the strip of stretch fabric, the protrusion being sewn on the strip of stretch fabric along the notch. A chair having a base, a seat, a backrest frame rotatably attached to the base, and a first energy mechanism for biasing the backrest frame toward an upright position, A flexible back flexibly flexible to form various curved shapes to support the seated user's back in response thereto; A belt bracket having a front extension flange pivotally connecting the flexible back to the back frame at the first connection; A second energy device, The flexible back has a second connection pivotally connecting the flexible back to the back frame at a second position vertically spaced from the first connection such that the flexible back is limited by the first connection and the second connection. Constrained to move across range, The second energy mechanism includes a force generating mechanism positioned at one of the first connection portion and the second connection portion and configured to bias the bracket and to bias the lumbar region of the flexible back forward with respect to the chair. . 77. The seated adult user of claim 76, wherein the belt bracket includes a side flange that positions the first connection at the back of the seat of the chair in a position where the first connection is aligned with the pelvic bone of a conventional seated adult user. When the lower part of the back is bent backwards, the pelvic portion of the backrest moves downward and backward, the lumbar portion of the backrest flexibly moves backwards to align more flatly with the pelvic portion, and the chest portion of the backrest A chair pivoted about a second connection, wherein the pelvic and chest portions are flexibly interconnected by the lumbar region and configured to move in a highly responsive manner to the movement of the seated adult user's back. Base assembly, With sheets, A backrest frame pivoted on the base assembly to move between an upright position and an inclined position; A flexible backrest having a front extension flange pivoted at the bottom connection for one of the backrest frame, the seat and the base assembly, and pivoted relative to the backrest frame at a fixed top connection, The lower connection is laterally spaced from the lower anterior center of the flexible back, so that the flexible back rests in response to the lower part of the seated back of the seated adult user and the back of the spine, Chair structure characterized in following the bending. 79. The chair structure according to claim 78, wherein the lower connection portion connects the flange of the flexible back to the back frame. 80. The chair structure according to claim 79, wherein the flexible back comprises a relatively rigid upper section and a lower section interconnected by flexible sections. delete delete Base assembly, With sheets, Inverted U-shaped back frame with a pair of predetermined shaped end sections pivoted relative to the base assembly, an intermediate upper section, a T-shaped upper connector protruding from the upper section, and a pair of lower connectors in the shaped end section and, A flexible back including an upper recess configured to receive and frictionally engage the upper connector, a belt bracket along a lower edge having opposite flanges extending a predetermined distance forward to connect to the lower connector; And a coupling mechanism for pivotally connecting the opposing flanges to the lower connector at a position proximate to the back of the seat. 84. The system of claim 83, wherein the flexible back comprises a flexible lumbar section, and the distance the flange extends forward is estimated to be approximately equal to the distance from the hip joint of the seated adult user to the lower vertebra of the seated user. The chair is then curved in a responsive manner to provide continued and comfortable support for the spine of an adult user seated upon bending. Backrest frame, A highly flexible back with a protruding lumbar support section having unique flexibility and flexibility, such that the flexible back can be curved into a plurality of different convex shapes, Upper and lower connections pivotally connecting the flexible back to the back frame, An adjustable force generating mechanism operably attached to at least one of said flexible back and back frame, The force generating mechanism is configured to provide an adjustable comfort force that adjustably adjusts the lumbar support section forward for optimal lumbar support for the seated user's back, but without altering the shape of the flexible back. Chair back structure, characterized in that to provide. Backrest frame, A highly flexible back with a forwardly protruding lumbar support section that can be flexibly moved into a plurality of different convex shapes that can provide posture support and comfortable support for the seated adult user's back Upper and lower connections pivotally connecting the flexible back to the back frame, Operatively attached to one or both of the flexible back and back frame to bias the lumbar support section forward for optimal lumbar support for the seated user's back and operable to the back frame and flexible back at the lower connection And an adjustable torsional force generating mechanism. 87. The chair back structure of claim 86, wherein the flexible back comprises a relatively rigid chest support section and a relatively rigid pelvic support section interconnected by a lumbar support section. 88. The chair back structure of claim 87, wherein the lumbar support section comprises a flexible material sheet. 87. The torsional force generating mechanism of claim 86, wherein the torsional force generating mechanism comprises a spring and a handle, the handle being rotatable to unwind or unwind to adjust the tension of the spring, the spring forwardly convex in the lumbar support section of the flexible back. Chair backrest structure, characterized in that it is operatively connected between the flexible backrest and the backrest frame to facilitate towards. 89. The chair back structure of claim 89, wherein the torsional force generating mechanism includes a lever to provide a mechanical advantage when adjusting the tension of the spring. A base assembly having a control housing having an energy source therein; A sheet on the base assembly, A back support operably interconnected to the energy source to move between an upright position and an inclined position, The back support includes a back frame and a back shell, The back shell includes an elastic flexible polymer sheet shaped to support the back region of a seated adult user, and is disposed in a semi-rigid lower region disposed in the pelvic region on the chair, over the lower region and in the lumbar region on the chair. A flexible central region and a semi-rigid upper region disposed above said central region within the chest region on the chair, The back frame includes a first attachment portion for coupling the upper region of the backrest shell to the backrest frame, and a plurality of second attachment portions for pivotally coupling the lower region of the backrest shell to the backrest frame, The second attachment flexes in a controlled and responsive manner in the lumbar region to support the backrest to ensure continuous and comfortable support of the spine of the seated adult user in the lumbar region during flexion of the spine of the seated adult user while seated. Constrains the movement of the lower region to occur, The central region of the backrest shell comprises a plurality of vertically spaced slots in the sheet extending horizontally across a portion of the central region of the backrest support, the slots ending before the outer peripheral edge of the sheet, The slots define a plurality of long horizontal elastic straps in the central area, each strap being dimensioned to provide elastic support for the adult user seated when the adult user is seated on the chair, The lower region of the backrest shell includes a reinforcement having a front extension flange pivotally coupled to a second attachment portion of the backrest frame, the reinforcement and pivot attachment being moved relative to at least a portion of the pelvic area of the seated user. A chair characterized by providing possible and reliable support. 92. The backrest frame of claim 91, wherein the backrest frame includes a first pivot portion, the backrest frame being pivotally attached to the base assembly for movement of the backrest support between an upright position and an inclined position, wherein the first pivot portion is a rear side of the seat. A chair, wherein the chair is approximately coincident with the axis positioned at and positioned on the hip joint of an adult user seated. delete delete A base assembly having a control housing having an energy source therein; A sheet on the base assembly, A back support operably interconnected to the energy source to move between an upright position and an inclined position, The back support includes a back frame and a back shell, The back shell includes an elastic flexible polymer sheet shaped to support the back region of a seated adult user, and is disposed in a semi-rigid lower region disposed in the pelvic region on the chair, over the lower region and in the lumbar region on the chair. A flexible central region and a semi-rigid upper region disposed above said central region within the chest region on the chair, The back frame includes a first attachment portion for coupling the upper region of the backrest shell to the backrest frame, and a plurality of second attachment portions for pivotally coupling the lower region of the backrest shell to the backrest frame, The second attachment flexes in a controlled and responsive manner in the lumbar region to support the backrest to ensure continuous and comfortable support of the spine of the seated adult user in the lumbar region during flexion of the spine of the seated adult user while seated. Constrains the movement of the lower region to occur, And a pivotable second attachment portion for pivotally coupling the lower region of the backrest shell to the backrest frame, comprising a convenience device for biasing the central region of the backrest shell in a forward direction. 95. The system of claim 95, wherein the lower region of the backrest shell includes a front extension flange pivotally coupled to a second attachment portion of the backrest frame, wherein the convenience device includes a torsion spring operatively interconnected to the front extension flange. A chair characterized by including. 98. The chair as claimed in claim 96, wherein the biasing device comprises means for adjusting the pretension in the torsion spring. A base assembly having a control housing having an energy source therein; A sheet on the base assembly, A back support operably interconnected to the energy source to move between an upright position and an inclined position, The back support includes a back frame and a back shell, The back shell includes an elastic flexible polymer sheet shaped to support the back region of a seated adult user, and is disposed in a semi-rigid lower region disposed in the pelvic region on the chair, over the lower region and in the lumbar region on the chair. A flexible central region and a semi-rigid upper region disposed above said central region within the chest region on the chair, The back frame includes a first attachment portion for coupling the upper region of the backrest shell to the backrest frame, and a plurality of second attachment portions for pivotally coupling the lower region of the backrest shell to the backrest frame, The second attachment flexes in a controlled and responsive manner in the lumbar region to support the backrest to ensure continuous and comfortable support of the spine of the seated adult user in the lumbar region during flexion of the spine of the seated adult user while seated. Constrains the movement of the lower region to occur, The lower region of the backrest shell includes a front extension flange defining a rotational axis at the pivotable second attachment portion of the backrest frame, the rotational axis when the seated adult user bends the lower part of the user's back backward. Or on the back of the seat such that the axis of rotation is positioned proximate to the pelvic bone of the seated adult user so that the lower portion of the arm moves downward and rearward and the central portion of the backrest shell is flexed rearward to align more flatly with the lower portion. A chair, characterized in that located in the rear. A base assembly having a control housing having an energy source therein; A sheet on the base assembly, A back support operably interconnected to the energy source to move between an upright position and an inclined position, The back support includes a back frame and a back shell, The back shell includes an elastic flexible polymer sheet shaped to support the back region of a seated adult user, and is disposed in a semi-rigid lower region disposed in the pelvic region on the chair, over the lower region and in the lumbar region on the chair. A flexible central region and a semi-rigid upper region disposed above said central region within the chest region on the chair, The back frame includes a first attachment portion for coupling the upper region of the backrest shell to the backrest frame, and a plurality of second attachment portions for pivotally coupling the lower region of the backrest shell to the backrest frame, The second attachment flexes in a controlled and responsive manner in the lumbar region to support the backrest to ensure continuous and comfortable support of the spine of the seated adult user in the lumbar region during flexion of the spine of the seated adult user while seated. Constrains the movement of the lower region to occur, And said back frame forms a curved arch. 92. The chair as claimed in claim 91, wherein the back frame comprises an inner metal reinforcement enclosed in an elastomeric sheath. 92. The chair of claim 91, wherein the chair comprises a seat operably mounted on a base assembly, wherein the seat forms a link interconnecting the back support to an energy source. A base assembly having a control housing having an energy source therein; A backrest assembly movably supported on the base assembly, The backrest assembly includes a backrest support having a backrest frame and a backrest shell connected to the backrest frame by at least one connection and operably interconnected to an energy source, a cushion on the front face of the backrest shell, and positioned in front of the backrest shell. Includes a vertically adjustable lumbar support, The back shell includes an elastic flexible polymer sheet adapted to support the back of a seated adult user, the sheet having a lower region disposed within the pelvic region on the chair and a center disposed within and above the lumbar region on the chair. An area and an upper area disposed above the central area and within a chest area on the chair, The lumbar support is configured to vertically adjust to change the shape of the front face of the backrest in the lumbar region and is movably supported on the backrest support, the vertically adjustable lumbar support facing non-parallel to the predetermined shape of the backrest shell. And a laterally extending handle configured to engage and follow the outer circumferential edge, wherein the handle slides with the vertically adjustable lumbar support so that the handle can be adjusted laterally and out of the following state. Chair characterized in that configured to possibly combine. A base assembly comprising a control housing having opposing flanges having a top edge, a lubrication cap attached to the top edge of the control housing, A backrest frame pivoted relative to the base assembly at the backrest pivot to move between an upright position and an inclined position; A seat support structure operatively supported on the base assembly and the back frame, The lubrication cap includes an upper surface defining a track slidably engaging the sliding member, The seat support structure includes a sliding member slidably engaged with the control housing for horizontal sliding movement, and a seat carrier pivoted relative to the sliding member at the front seat pivot and pivoted against the back frame at the rear seat pivot. Chair. 103. The seat of claim 103, wherein the chair comprises a seat shell attached to a seat support structure, the seat shell configured to comfortably support the body of a conventional seated adult user, and the buttocks of a seated adult user. A chair comprising a front section configured to comfortably support most of the weight of a supported and seated adult user, and a flexible section connecting the rear section and the front section. 107. The chair of claim 104, wherein the chair comprises a gas spring extending between the seat support structure and the front section, the gas spring being a releasable automatic locking device. 105. The chair as claimed in claim 105, comprising a curved rod shaft pivoted about the seat support structure and the front section and operably connected to the gas spring. 107. The chair of claim 104, comprising a leaf spring operably supporting the front section on the seat support structure. 103. A chair as claimed in claim 103, comprising a spring mechanism positioned in the control housing and operably connected to the sliding member. 109. The spring device of claim 108, wherein the spring mechanism further comprises a spring positioned laterally within the control housing, further comprising a lever operatively pivoted relative to the control housing, the lever having one end operatively engaged with the spring. And a second end operatively engaged with the seat support structure. A base assembly comprising a control housing, A backrest frame pivoted relative to the base assembly at the backrest pivot to move between an upright position and an inclined position; A slide member slidably engaging the control housing for horizontal slide movement and a seat carrier pivoted against the slide member at the front seat pivot and pivoted against the back frame at the rear seat pivot, the base assembly and the back frame A sheet support structure operatively supported on the substrate, One end and seat support structure positioned within the control housing, the spring operatively connected to the sliding member and laterally positioned within the control housing, the spring operatively pivoted with respect to the control housing and operatively engaged with the spring; A spring mechanism further comprising a lever having a second end that is operatively coupled; A pivot member having interfacing surfaces with the lever and at least one surface of which is curved such that the device acts like a rack-pinion and is adjustable to change the support point on the lever to adjust the length of the moment arm on which the spring acts. Chair comprising a. 119. The chair of claim 110, comprising a backrest stop located within the control housing, the backrest stop configured to engage the seat support structure to limit the inclination of the backrest frame. 119. The backrest stop of claim 111, wherein the backrest includes a cam pivoted about the control housing to rotate about an upright axis, wherein the cam includes a plurality of steps that can be selectively positioned to engage the seat support structure. Chair. A base assembly comprising a control housing, A backrest frame pivoted relative to the base assembly at the backrest pivot to move between an upright position and an inclined position; A slide member slidably engaging the control housing for horizontal slide movement and a seat carrier pivoted against the slide member at the front seat pivot and pivoted against the back frame at the rear seat pivot, the base assembly and the backrest A seat support structure operatively supported on the frame, And a seat shell slidably supported on the seat support structure for selective depth adjustment such that the depth of the seat shell can be selectively adjusted relative to the backrest frame. A base assembly comprising a control housing having sidewalls defining a track; A seat having a front part and a rear part having a bearing slidably engaged with the track, the seat including a seat shell having a front part bent and supported; A backrest pivoted relative to the base assembly and independently pivoted relative to the seat to move between an upright position and an inclined position, Located in the central housing, operatively connected to the seat to bias the seat rearward, and comprising a lever pivoted relative to the control housing and an elongation / compression spring positioned within the control housing to bias the backrest into an upright position. A spring mechanism defining a moment arm with a spring for transferring energy from the spring to the seat, An operative connection between the front portion of the shell and the rest of the seat adapted to support the weight of a typical seated adult user, the gas spring operable to adjust the position of the front relative to the rest of the seat, And the rear portion of the seat is pivoted relative to the back so that the seat moves forward when the backrest is inclined and the seat rear portion moves forward and downward synchronously. 119. The chair of claim 114, wherein the gas spring is automatically lockable and unlockable. 116. The chair of claim 115, comprising a control unit coupled to the seat and having a link operatively connected to the gas spring to release the gas spring for adjustment. A base assembly comprising a control housing having sidewalls defining a track; A seat having a front part and a rear part having a bearing slidably engaging the track, the seat comprising a seat shell having a bent support front part; A backrest pivoted relative to the base assembly and independently pivoted relative to the seat to move between an upright position and an inclined position, Located in the central housing, including an extension / compression spring operatively connected to the seat to bias the seat rearward and a lever pivoted relative to the control housing, the spring to bias the backrest to an upright position. A spring mechanism defining a moment arm with a spring for transferring energy from the sheet to the seat, A leaf spring positioned between the front section of the seat and the rest of the seat to support elastically, And the rear portion of the seat is pivoted relative to the backrest such that the seat moves forward when the backrest tilts and the seat back portion moves forward and downward synchronously. A base assembly comprising a control housing having sidewalls forming a track; A seat having a front portion and a rear portion with bearings slidably engaged with the track, the seat comprising a depth adjusting structure to adjust the depth of the seat shell to the seat shell and the backrest; A backrest pivoted relative to the base assembly and independently pivoted relative to the seat to move between an upright position and an inclined position, Located in the central housing and operably connected to the seat to bias the seat rearward, the extension / compression spring positioned within the control housing and a lever pivoted relative to the control housing, for biasing the backrest to an upright position. A spring mechanism defining a moment arm with a spring for transferring energy from the spring to the seat, And the rear portion of the seat is pivoted relative to the backrest such that the seat moves forward when the backrest tilts and the seat back portion moves forward and downward synchronously. 119. The chair of claim 118, wherein the seat comprises a seat carrier supporting the seat shell and a linear bearing slidably engages the shell on the seat carrier. 119. The chair of claim 119 including a latch operatively extending between the seat carrier and the shell to hold the shell in a selected depth position. 121. The chair as claimed in claim 120, comprising a control coupled to the seat to actuate the latch. A base assembly comprising a control housing, An inclined backrest frame which is skinned relative to the base assembly to move between an upright position and a complete inclined position; A seat slidably supported on the control housing and pivotally supported on the back frame; Operatively supported on the base assembly to engage the seat to stop the seat at the same position and stop the tilt of the backrest at the selected position prior to reaching the full inclined position, and to adjust the seat-engaging member and the seat-engaging member A variable back stop mechanism having an actuator lever for moving, And the seat-engaging member and the lever comprise interlocking teeth to provide a non-slip engagement. 123. The chair as recited in claim 122, wherein the seat-binding member comprises a movable cam having steps formed to selectively engage the seat. 124. The chair of claim 123, wherein the variable back stop mechanism includes a spring detent for retaining the cam at a selected stop position where a particular one of the steps is positioned to engage the seat. 124. The chair as recited in claim 124, comprising an actuator coupled to the cam to rotate the cam to select a particular one step. A base assembly comprising a control housing, A tiltable back frame pivoted relative to the base assembly to move between an upright position and a full tilt position; A seat slidably supported on the control housing and pivotally supported on the back frame; A variable back stop mechanism operably supported on the base assembly to engage the seat to stop the seat at the same time and stop the tilt of the backrest at the selected position before reaching the complete tilt position; An actuator with a lever connected to the cam and pivoted relative to the control housing to rotate the cam to select a particular one step, The variable back stop mechanism includes a moveable cam having a step formed to selectively engage the seat, and further comprising a spring detent that holds the cam at a stop position selected such that a particular step of the step engages the seat. Including, And said lever and cam comprise interlocking teeth. 126. The chair of claim 126, wherein the actuator comprises a rotatable handle operably connected to the lever. 127. The chair of claim 127 wherein the actuator comprises a rod connecting the handle to the lever. 129. The pivot of claim 127, wherein the handle includes a radially extending protrusion, the pivot allowing the handle to rotate about a first axis and the lever to rotate about a second axis that is oblique and not parallel to the first axis. Chair connected to the lever by a slide joint, wherein the handle drive rotation of the lever is not wound. A base assembly comprising a control housing, A tiltable back frame pivoted relative to the base assembly to move between an upright position and a full tilt position; A seat slidably supported on the control housing and pivotally supported on the back frame; It is operably supported on the base assembly to engage the seat to stop the seat and stop the tilt of the backrest at the selected position before reaching the complete tilted position, provided with steps shaped to selectively engage the seat. A movable cam, the cam further comprising a corrugated surface adapted to engage a detent that selectively retains the step in position to engage the seat, and add a tooth adapted to engage a mating tooth on the actuator actuating the cam Chair characterized in that it comprises a variable back stop mechanism including. A front section shaped to comfortably support the thighs of a conventional seated adult user, a rear section shaped to comfortably support the buttocks of a seated adult user, and a flexible intermediate section connecting the front and rear sections And the anterior section is positioned on the seat shell in the middle or anterior and is generally forward of the expected position of the seated adult user's hip joint so that for most adult users the weight of the seated adult user is generally supported by the posterior section. Elastically flexible seat shells, A seat cushion supported on the seat shell, A fan-shaped seat carrier supporting the rear section of the shell, the fan-shaped seat carrier comprising a front extension section extending below the flexible middle section and spaced apart below the flexible middle section and not connected to the flexible middle section, Pre-tensioned transverse leaf springs operably supporting the front section of the seat shell on the front extension section of the seat carrier such that the front section is adjustable relative to the rear section to provide optimal thigh pressure and support for the seated adult user. Seat structure of a chair comprising an adjustable femoral flexion support mechanism comprising a. A front section shaped to comfortably support the thighs of a conventional seated adult user, a rear section shaped to comfortably support the buttocks of a seated adult user, and a flexible intermediate section connecting the front and rear sections And the anterior section is positioned on the seat shell in the middle or anterior and is generally forward of the expected position of the seated adult user's hip joint so that for most adult users the weight of the seated adult user is generally supported by the posterior section. Elastically flexible seat shells, A seat cushion supported on the seat shell, A fan-shaped seat carrier supporting the rear section of the shell, the fan-shaped seat carrier comprising a front extension section extending below the flexible middle section and spaced apart below the flexible middle section and not connected to the flexible middle section, The flexure rod axis and the flexure rod axis are operably supported on the forward extension section of the seat carrier so that the forward section is adjustable relative to the posterior section to provide optimal thigh pressure and support to the seated adult user. And an adjustable thigh flexure support mechanism comprising a releasably lockable gas spring that holds the flexure rod axis in a selected direction after rotation. A front section shaped to support a typical seated adult user, a rear section shaped to comfortably support the buttocks of a seated adult user and comfortably support most of the weight of a seated adult user, and a flexible intermediate section A flexible seat shell containing, A full width rear section and a bottom panel having a width less than the full width rear section and forming a partial width front section extending forward from the center of the rear section, the full width rear section having a partial width front section spaced below the front section; A T-shaped seat support fan shaped to extend and support the rear section of the shell, And an adjustable thigh support mechanism for controlably connecting and supporting the front section on the partial width front section. 134. The seat structure of claim 133, wherein the adjustable thigh support mechanism includes a pretensioned transverse leaf spring. 134. The seat structure of claim 134, wherein the adjustable thigh support mechanism includes a flexure rod axis and a releasably lockable gas spring that retains the flexure rod axis in a predetermined direction after rotating the flexure rod axis. A chair having a tiltable backrest and a movable seat operatively supported to synchronously move with the backrest, A seat carrier having a T-shaped body comprising a front section and a rear section and including linear bearings located on each side of the front section and on each side of the rear section; A fan-shaped seat frame, the depth of which is adjustable on the seat carrier by including a bottom panel having a flat surface slidably engaged with the corresponding one of the linear bearings, the seat cushion being configured to support the seated user; And the seat carrier includes a pivot configured to pivotally mount the seat carrier to a support that movably supports a movable seat relative to the tiltable backrest. 138. The chair of claim 136, wherein one of the seat carrier and the seat frame includes a series of notches extending in the front-rear direction, and the other of the seat carrier and the seat frame includes a latch that selectively engages the notches. . 138. The seat carrier of claim 137, wherein the seat carrier includes an upwardly formed stop tab and includes a top mounted stop limiter attached to the seat frame, the stop limiter extending downward through the seat frame and having a maximum depth of the seat frame on the seat carrier. And a protrusion shaped to engage the stop tab to form a position and a minimum depth position. 138. The chair of claim 136, wherein the seat frame includes a flange that captures at least two bearings to prevent the seat frame from being lifted upright and removed from the seat carrier. A base assembly comprising a control housing having at least one upward flange and a sliding bearing supported over each upward flange; A backrest frame pivoted relative to the base assembly at the backrest pivot to move between an upright position and an inclined position; A sliding member operably supported on the base assembly and the backrest frame and slidably engaging the sliding bearing of each upward flange for generally horizontal sliding movement and pivoted relative to the sliding member at the front seat pivot; And a seat support structure comprising a seat carrier pivoted relative to the back frame at the seat pivot. 141. The chair of claim 140, wherein the at least one upward flange comprises two parallel side flanges on the control housing. 143. The chair of claim 141 wherein each sliding bearing comprises a polymeric member attached to an upper edge of the side flange. 141. The chair of claim 140, wherein the base assembly comprises a base frame comprising a housing and further comprises side arms supporting the back frame at the back pivot. 109. The chair of claim 103, wherein the base assembly includes a base frame having a housing and further includes side arms supporting the back frame at the back pivot. 119. The chair of claim 110, wherein the base assembly comprises a base frame comprising a housing and further comprises a side arm supporting the back frame at the back pivot. 116. The chair of claim 113, wherein the base assembly includes a base frame comprising a housing and further includes side arms supporting the back frame at the back pivot. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete Providing a chair element having laterally extending and facing protrusions, Providing a backrest frame with an end section having a recess therein, Bending the end section of the backrest frame while simultaneously placing a recess in the end section on the protrusion, Releasing the back frame such that the back frame is elastically restored to an initial shape that holds the back frame in place and pivotally connects the back frame to the chair element. 166. The chair element of claim 163, wherein the chair element comprises a seat, the method of assembling the chair comprising providing a base assembly with side arms, the end section being positioned between the side arm of the base assembly and the side portion of the seat. And bending the end section to cause the chair to assemble. 175. The method of claim 164, wherein the side arms comprise facing second protrusions, the end sections comprise second recesses, and the chair assembly method includes positioning a second recess on the second protrusions. Chair assembly method comprising a. 167. The method of claim 165, wherein the first and second protrusions on the sides of each chair face face in opposite directions. delete delete 167. The base assembly of claim 164, wherein the base assembly comprises a base frame with a housing, the opposing side arms extend laterally and upwardly from the housing, wherein the chair assembly method includes an end section of a predetermined shape inside the upper end of the side arm. Positioning at but substantially outside and on top of the housing. A base assembly for supporting the chair on a floor while the seated user performs a task; A backrest frame pivoted relative to the base assembly at the backrest pivot to move between a plurality of work positions including upright and inclined work positions; A seat pivoted relative to the backrest frame at the seat pivot spaced rearward and downwardly spaced from the backrest pivot, and slidably supported at the front portion of the base assembly to move horizontally, The backrest pivot and seat pivot are interconnected and arranged to move the seat forward when tilting the backrest frame and to move the rear portion of the seat downward synchronously pivotally, so that the seated user is comfortable in the upright and tilting working positions. Supported, and can continue to work while moving between an upright working position and an inclined working position without continuously moving and adjusting the base assembly back and forth relative to the stationary work surface, The base assembly includes a control housing having an energy mechanism therein operatively coupled with one of the back frame and the seat to bias the back frame to an upright position, The seat includes a seat sliding member slidably engaged with the control housing and a seat support carrier pivotally engaging the seat slide at the first pivot and pivotally engaging the back frame at the second pivot. Chair features. delete 172. The chair of claim 170, wherein the base assembly includes a back arm extending generally upwardly adjacent the seat to support a portion of the back frame and the seat. 172. The chair of claim 172 wherein the back frame is pivoted about the side arms. 173. The chair of claim 173, wherein the seat is pivoted against the back frame in a position generally proximate to the side arms. A base assembly for supporting the chair on a floor while the seated user performs a task; A backrest frame pivoted relative to the base assembly at the backrest pivot to move between a plurality of work positions including upright and inclined work positions; A seat pivoted relative to the backrest frame at the seat pivot spaced rearward and downwardly spaced from the backrest pivot, and slidably supported at the front portion of the base assembly to move horizontally, The backrest pivot and seat pivot are interconnected and arranged to move the seat forward when tilting the backrest frame and to move the rear portion of the seat downward synchronously pivotally, so that the seated user is comfortable in the upright and tilting working positions. Supported, and can continue to work while moving between an upright working position and an inclined working position without continuously moving and adjusting the base assembly back and forth relative to the stationary work surface, The base assembly includes a control housing having an energy mechanism therein operatively coupled with one of the back frame and the seat to bias the back frame to an upright position, The base assembly includes a back arm and a side arm extending upwardly close to the seat to support a portion of the seat, The back frame is pivoted about the side arm, The seat is pivoted against the backrest frame at a position proximate to the side arms, The energy mechanism includes a spring positioned laterally in the control housing and a lever operatively connecting the spring to one of the seat and back frame. 175. The chair of claim 175, wherein the chair comprises an adjustment mechanism that adjusts the lever to change the biasing force transmitted from the spring to the seat, the adjustment mechanism including the lever and releasably adjusting the back frame to an upright position. A chair characterized by defining an adjustable moment arm on the lever. 172. The chair of claim 170, wherein the chair comprises a spring positioned transversely within the control housing and further comprising a lever operably connecting the spring to one of the seat and back frame. A base assembly for supporting the chair on a floor while the seated user performs a task; A backrest frame pivoted relative to the base assembly at the backrest pivot to move between a plurality of work positions including upright and inclined work positions; A seat pivoted with respect to the backrest frame at the seat pivot spaced rearward and downwardly spaced from the backrest pivot and slidably supported at the front portion of the base assembly for horizontal movement; A lever operatively connecting the spring to one of the seat and the backrest, The backrest pivot and seat pivot are interconnected and arranged to move the seat forward when tilting the backrest frame and to move the rear portion of the seat downward synchronously pivotally, so that the seated user is comfortable in the upright and tilting working positions. Supported, and can continue to work while moving between an upright working position and an inclined working position without continuously moving and adjusting the base assembly back and forth relative to the stationary work surface, The base assembly includes a control housing having an energy mechanism therein operatively coupled with one of the back frame and the seat to bias the back frame to an upright position, The energy mechanism comprises a spring positioned transversely within the control housing, The lever is pivotable about a vertical axis with the first end connected to the spring and the second end operably connected to the seat to bias the seat backwards and then to bias the back frame to the upright position. chair. 172. The chair of claim 170, wherein the control housing comprises an opposite side flange and the seat comprises a bearing slidably coupled with the side flange. delete 172. The seat of claim 170, wherein the seat comprises a flexible seat shell having a back section adapted to support the buttocks of the seated adult user, and a front section adapted to support the thighs of the seated adult user and flexibly connected to the back section. And the rear section is carried and supported by the seat support carrier. 172. The seat of claim 170, wherein the seat comprises a seat support carrier slidably connected to the base assembly and pivotally connected to the back frame, and a seat shell slidably supported on the seat support carrier for manually operated depth adjustment. Chair characterized in that. A base assembly for supporting the chair on a floor while the seated user performs a task; A backrest frame pivoted relative to the base assembly at the backrest pivot to move between a plurality of work positions including upright and inclined work positions; A seat pivoted with respect to the backrest frame at the seat pivot spaced rearward and downwardly spaced from the backrest pivot and slidably supported at the front portion of the base assembly for horizontal movement; A back rest stop mechanism attached to the control housing and configured to selectively engage the seat to restrict forward movement of the seat and thereby selectively limit the inclination of the back frame; The backrest pivot and seat pivot are interconnected and arranged to move the seat forward when tilting the backrest frame and to move the rear portion of the seat downward synchronously pivotally, so that the seated user is comfortable in the upright and tilting working positions. Supported, and can continue to work while moving between an upright working position and an inclined working position without continuously moving and adjusting the base assembly back and forth relative to the stationary work surface, And the base assembly includes a control housing having an energy mechanism therein operatively coupled with one of the back frame and the seat to bias the back frame into an upright position. 172. The chair of claim 170, wherein the chair includes a flexible back assembly attached to the back frame at at least two vertically spaced positions and configured to bend between at least two vertically spaced positions to provide optimal lumbar support. Chair characterized in that. 185. The chair of claim 184, wherein the flexible back assembly includes a one-piece shell that is elastically curved. 185. The chair of claim 184, wherein the flexible back assembly comprises a multi-piece element assembly each having a surface supporting a portion of a user's back. A movable base assembly comprising a control housing; A backrest pivoted relative to the base assembly to move between an upright position and an inclined position, A seat operably supported on the base assembly and connected to the backrest to move substantially between the rear work position and the front work position, A spring mechanism positioned laterally in the control housing and a lever pivotally coupled to the seat and operatively coupled to the seat to bias the seat toward the rear working position while simultaneously biasing the backrest toward the upright position, The seat includes a front portion slidably connected to the base assembly such that the seated user's leg moves horizontally forward upon inclination of the back such that the leg of the seated user does not undesirably rise from the floor surface, The seat is flexibly connected to the front part and is supported so that the seated user is comfortably posture supported during the inclination by the angular synchronous movement of the seat and the back, and the maximum forward movement of the seat and the maximum angle movement of the backrest are seated during the inclination. Operationally connected to the backrest to move downwards and forwards during incline to limit the hand's hand to a relatively constant stroke, adding a rear portion that allows the seated user to continue working easily and comfortably in all seating positions Including, And the control housing includes a side arm and the seat includes a bearing slidably engaged with the side arm. delete 187. The chair of claim 187, wherein the side arms pivotally support the backrest at a position at the back of the seat adapted to align with the hip joint of the seated user. delete 187. The chair as recited in claim 187, wherein the spring mechanism includes a spring that resiliently supports the front section of the seat to bend to provide enhanced comfort for a seated user. 192. The chair of claim 191, wherein the seat further comprises a release and lockable gas spring that operatively and operatively supports the front section for adjustable movement to provide adjustable comfort for the seated user. . delete 189. The rear part of claim 189, wherein the rear portion is configured to support the majority of the weight of the seated adult user's buttocks and the seated adult user, and the front portion of the seated adult user without raising the leg of the seated adult user during inclination of the backrest. A chair characterized in that the thigh can be bent and configured to comfortably support it. 189. The chair of claim 189, wherein the seat comprises a seat support carrier slidably supported on the base assembly and pivotally engaging the backrest frame, and a seat shell manually adjustable on the seat support carrier. A base assembly having side arms, A backrest frame pivoted relative to the base assembly at the backrest pivot to move between a plurality of work positions including upright and inclined work positions; A seat pivoted against the back frame at the seat pivot and slidably supported at the front of the base frame, The back frame comprises a right and left end section of a predetermined shape located between the sides of the seat and the associated arms of the side arms and on opposite sides of the seat, The end section of the predetermined shape supports the first pivot bearing at the seat pivot and the second pivot bearing at the backrest pivot so that the seated user can continue working while moving between the upright and inclined working positions. Chair. A movable spider leg base assembly having a control housing and an upwardly extending side arm; Inverted U with adjacent shaped ones of the side arms, each having an end section of a predetermined shape pivoted in a backrest pivot with a first stud and a rotatable first bearing associated with the first stud, respectively. With a backrest frame, A seat slidably supported on the control housing, the seat having a second stud and a rotatable second bearing that engages the second stud, respectively, and pivoted against the end section at a seat pivot that is spaced apart from the backrest pivot; A transverse spring, a lever operatively engaging the spring and the seat to bias the seat back toward the upright position, and subsequently supporting the back frame towards the upright position, and defining a support point moving during the inclination and restraining the force of the spring on the seat And an adjustable energy mechanism having an adjustable pivot member that operatively engages with a manually adjustable and changeable lever to reposition the support point for adjustable control. delete delete 181. The chair of claim 181, wherein the seat further comprises a spring that elastically supports the right and left sides of the front section to bend independently to provide enhanced comfort for the seated user. 181. The chair of claim 181, wherein the seat further comprises a release and lockable gas spring that operatively and adjustablely supports the front section for adjustable movement to provide adjustable comfort for the seated user. . A base assembly with a control housing, An energy source located within the control housing, A sheet operably supported on the base assembly and operatively interconnected to the energy source so as to move generally horizontally between the front and rear positions; A backrest support having a backrest frame and a backrest frame for supporting the backrest shell, A variable back stop mechanism supported on the base assembly and operatively coupled to the seat, The back frame comprises a first pivot portion pivotally fastened to the base assembly and a second pivot portion pivotably fastened to the seat such that the back support moves in an upright and inclined position; The energy source biases the back support to an upright position by pressing the seat backwards, and the backward movement of the seat rotates the back support to a generally upright position at the first pivot, And the variable backrest stop mechanism comprises a variable backrest stop mechanism configured to simultaneously stop the backrest and the backrest support in a plurality of selectable positions between upright and inclined positions. 202. The chair of claim 202, wherein the first pivot axis is located on the back of the seat such that the first pivot axis is aligned with the hip joint of the seated adult user. 202. The seat of claim 202, wherein the seat is slidably coupled with a seat front slide portion adapted to slide forward and backward on the control housing, a seat carrier pivotally interconnected to the control housing and the front slide portion; And a seat frame adapted to support the buttocks and thighs of the seated adult user. 204. The seat shell of claim 204, wherein the seat shell comprises: a rear section configured to support the hip of the seated adult user and to support most of the weight of the seated adult user; An anterior section adapted to support the thigh of the seated adult user, A flexible zone having an adjustment device connecting the rear section and the front section and connected to the front section and configured to angle the front section of the seat shell with respect to the rear section, And the adjustment device is attached to the lower side of the front section of the seat shell. delete A base assembly with a control housing, An energy source located within the control housing, Thigh of the adult user seated with the rear section operably supported on the base assembly, operatively interconnected to the energy source, and supporting the buttocks of the seated adult user for generally horizontal movement between the front and rear positions. A seat having a seat shell having a front section adapted to support the A backrest support having a backrest shell and a backrest frame supporting a backrest shell, And the back frame comprises a first pivot portion at which the back frame is pivotally fastened to the base assembly and a second pivot portion at which the back frame is pivotably fastened to the seat. A seating unit having a base, a seat, a backrest frame rotatably attached to the base, and a first energy mechanism operably connected to the backrest frame and the base to bias the backrest frame toward an upright position, A flexible back flexibly flexible to form various curved shapes to support the seated user's back in response thereto; A belt bracket having a front extension flange pivotally connecting the flexible back to the back frame at the first connection; A second energy device, The flexible back has a second connection pivotally connecting the flexible back to the back frame at a second position vertically spaced from the first connection such that the flexible back is limited by the first connection and the second connection. Constrained to move across range, The second energy mechanism includes a force generating mechanism positioned at one of the first connection portion and the second connection portion and configured to bias the bracket and to bias the lumbar region of the flexible back forward relative to the seating unit. Seating unit. 208. The system of claim 208, wherein the flexible back includes an upper section and a lower section operatively connected to each other for reverse rotational movement, the upper section pivoting relative to the back frame at at least one upper connection, and the lower section being at least A seating unit comprising a front extension flange pivoted against the back frame at one lower connection. 208. The seating unit of claim 208, wherein the flexible back includes a back shell having upper and lower rigid sections connected by a flexible zone located in the lumbar region of the seated user. 209. The torsional lumbar support mechanism of claim 208, comprising: a torsional lumbar support mechanism operably attached to the backrest shell, wherein the torsional lumbar support mechanism biases the shell forward in a convex shape for optimal lumbar support. Seating unit. 208. The seating unit of claim 208, comprising a torsional lumbar support mechanism attached to one of the first and second connections for biasing the flexible back into a convex shape that projects forward. 213. The lumbar support of claim 208, wherein the flexible back comprises a backrest shell, wherein the seating unit comprises a vertically adjustable lumbar support operably attached to the front face of the backrest shell of the flexible back. And the support is configured to change the bearing force at the front face of the flexible back of the lumbar region of the seated user. With a single back frame, A flexible back having a flexible anterior protruding lumbar support section that can be bent into a plurality of different convex shapes, At least two connections pivotally connecting the flexible back to the back frame, An adjustable force generating mechanism operably attached to at least one of said flexible back and back frame, The force generating mechanism is configured to provide a biasing force to bias the lumbar support section for optimal lumbar support for a seated user's back, but provides a biasing force without changing the shape of the flexible backrest. Back structure for seating unit. 214. The backrest structure of claim 214, wherein the adjustable force generating mechanism comprises a torsion mechanism. 214. The backrest structure of claim 214, wherein the flexible back comprises a relatively rigid chest support section and a relatively rigid pelvic support section interconnected by a lumbar support section. 214. The backrest structure of claim 214, wherein the adjustable force generating mechanism comprises a biasing spring, the biasing spring biasing the lower region for pivotal behavior about the lower connection. Base assembly, With sheets, A backrest frame pivoted on the base assembly to move between an upright position and an inclined position; A flexible backrest having a front extension flange pivoted at the bottom connection for one of the backrest frame, the seat and the base assembly, and pivoted relative to the backrest frame at a fixed top connection, The lower connection part is spaced forward from the lower front center of the flexible back, so that the flexible back rests in response to the seated user's lower back and the back of the spine, and follows the flexion of the seated back of the seated user. Seating unit structure, characterized in that. 218. The seating unit structure of claim 218, wherein the lower connection connects a flange of the flexible back to the back frame. 219. The seating unit structure of claim 219, wherein the flexible back includes a relatively rigid upper section and a lower section interconnected by flexible sections. 218. The flexible backrest of claim 218, wherein the flexible back includes an upper section and a lower section operably connected to each other for reverse rotational movement, the upper section pivoting relative to the backrest frame at at least one upper connection, and the lower section being at least A seating unit structure comprising a front extension flange pivoted against a back frame at one lower connection. 226. The seating unit structure of claim 218, wherein the flexible back includes a back shell having upper and lower rigid sections connected by a flexible zone located in the lumbar region of the seated user. 218. The seating unit structure of claim 218, comprising a torsional lumbar support mechanism attached to one of the lower connections for biasing the flexible back into a convex shape that projects forward. 218. The seating unit structure of claim 218, wherein the flexible back includes a belt bracket attached along a lower edge of the flexible back, wherein the belt bracket includes a flange that forms part of the lower connections. With frame member, Backrests that can be bent into various shapes to ergonomically support the lumbar and torso of the seated user, A belt bracket having a flange extending from said backrest and attached to said backrest, The flange pivotally connects the backrest to the frame member at a first connection, the backrest pivots to the frame member at a second connection perpendicularly spaced from the first connection, and the backrest is first and first. 2 A seating unit, constrained by a connection and a flange, coupled with a user seated in the lumbar region of the backrest to provide ergonomic lumbar support. 255. The seating unit of claim 225, wherein said backrest is made of a flexible material. 255. The seating unit of claim 225, wherein said backrest forms a curved sheet shape and a flange extends forwardly from said curved sheet shape. 225. The seating unit of claim 225, comprising a force generating energy mechanism for biasing the lumbar spine forward relative to the seated user. 255. The seating unit of claim 225, wherein the backrest comprises a backrest shell having upper and lower rigid sections connected by a flexible zone located in the lumbar region of the seated user. Backrest frame, A backrest operatively attached to the backrest frame at upper and lower connections, The backrest includes a rigid pelvic portion and a rigid chest portion connected by a flexible lumbar region, wherein the lower connection is located in front of the pelvic portion, The upper and lower connections, the chest, the pelvis and lumbar region, when the seated user flexes the lower portion of his back backward, the pelvic portion of the backrest pivots downward and backward, and the lumbar portion of the backrest It flexes backwards to align with the pelvic part more planarly, and the chest part of the backrest is configured to pivot about the upper connection, so that, in cooperation with the backrest frame, the backrest is very comfortable and seated with significant flexion of the torso and spine of the user And a posture support for the back of the seated user supporting the movement in the correct posture. 234. The seating unit of claim 230, wherein said backrest frame forms a lower pivot and is movable between an upright position and an inclined position. 234. The seating unit of claim 230, wherein the lumbar region comprises a flexible material sheet. 234. The seating unit of claim 230, comprising a force generating mechanism operably connected to the backrest to bias the lumbar region forward. 231. The seating device of claim 230, comprising a convenience device for biasing the flexible back to a shape in which the lumbar region protrudes forward, the comfort device providing convenience but not altering the shape of the flexible back. unit. A flexible shell having at least one upper connection and at least one lower connection vertically spaced from the at least one upper connection, The at least one lower connection is in front of the bottom of the shell, the lower connection defining an axis that is aligned with the hip bone of the seated user when the seated adult user leans against the shell, The shell having a rigid thoracic part, a rigid pelvic part and a lumbar spine part, The shell can be easily bent because the lumbar region can be bent considerably in the horizontal forward direction to provide various shapes for optimal lumbar support, but the lumbar region is almost non-near in the direction of the thoracic and pelvic side. Since the lumbar part is compressive, the chest and pelvis parts pivot along a predetermined path around the upper and lower joints when the lumbar part is bent, so that the flexible back rests the lumbar part by the back of the user seated. Flexible backrest, characterized in that the bending between the upper connection and the lower connection is controlled during bending. 238. The flexible device of claim 235, comprising a convenience device for biasing the flexible back to a shape in which the lumbar region protrudes forward, the comfort device providing convenience but not altering the shape of the flexible back. Sex back. Donation, A seat support structure movably mounted on the base; A backrest support pivoted on the seat support structure to move between an upright position and an inclined position; A seat located on the seat support structure; A flexible backrest connected to the backrest support at at least one upper connection and to one of the seat and backrest support at at least one lower connection vertically spaced from the at least one upper connection; The seat support structure moves the seat forward synchronously with the back support according to the inclination of the back support, The at least one lower connection portion restrains the bottom of the flexible back with a predetermined range of motion, and the flexible back is bendable, so that the flexible backrest between the upper connection part and the lower connection part when the user's back is bent. Seating unit, characterized in that the bending is controlled. 237. The seating unit of claim 237, wherein said movement forward of said seat occurs during the inclination of said back support. 237. The seating unit of claim 237, wherein an energy mechanism biases the back support to the upright position. 237. The seating unit of claim 237, wherein the back support and the seat support structure are operably connected to the base to move the back and the seat in synchronous behavior of the backrest by the seated user.

Images