ES2749583T3 - Combined backrest stop and tension function for one seat unit - Google Patents

Abstract

A seat unit having a base (21; 21B), a seat (22), a backrest (23; 23B) and a control (24) that is arranged to operatively engage and support the backrest for movement between the upright and reclined positions, the control including a housing, a first mechanism (123 ', 137, 123B', 137B) arranged to provide a deflection support force to the backrest during recline, an energy adjustment mechanism (150) and a backrest stop mechanism (203), characterized in that: the control includes an actuator (155, 156, 205) movable to a first operating position to selectively engage the power adjustment mechanism, and movable to a second operating position to selectively engaging the backstop mechanism, the power adjusting mechanism (150) comprising a reinforcing mechanism (25) capable of increasing the supporting force, the actuator (155) comprising an activation selector device On / Off (155) to selectively activate and deactivate the booster mechanism.

Description

DESCRIPTION

Combined backrest stop and tension function for one seat unit

The present invention relates to a seat unit having an adjustable backrest tension function and an adjustable backrest stop function.

Comfort, simplicity and adjustability remain highly demanded features in the seats. Specifically, it is desirable to provide a control that is easy to operate, simple to manufacture and assemble, with a relatively low cost and relatively few components, and that has a modern, elegant and slim appearance. In addition, it is desirable that the frame complement the ability to provide weight-activated support during recline so that heavier seated users feel secure in reclining even without adjustment.

In particular, when it comes to adjustability, it is desirable to provide adjusters that are easier to adjust and more intuitive to operate. For example, many chairs that have a reclining back also have an adjustable spring to vary the backrest support provided when reclining. However, many adjusters work against the spring to compress the spring during adjustment. This requires considerable effort, even if a mechanical advantage is provided, as the springs are substantial and there is a significant energy input required to compress the spring. Even adjustments that decompress the spring require an effort to overcome the friction forces that prevent unexpected decompression. In addition, users constantly seated find themselves searching among several different controls trying to find the correct control for the setting they want. Furthermore, once the proper control has been selected, the user has yet to find out which direction the control is adjusted to achieve the desired effect. It is desirable to find a single control mechanism that provides a logical and intuitive arrangement of the backrest settings, where increasing support settings cause an increasing level of backrest support, even though increased support is provided by different mechanisms. .

In addition to the above, it is desirable to provide a chair that is optimally designed to use recyclable parts, and that uses components that can be easily separated for recycling and / or repair. Expanded thermoset foam products are generally classified as non-recyclable, and are also generally considered environmentally friendly compared to steel, meltable thermoplastic, recyclable materials, and more natural materials. Removing thermoset foam would be an important step towards making a 100% recyclable chair. However, comfort and cost advantage must be maintained for competitiveness reasons.

EP1578230 discloses a seat unit including a base, a reclining backrest component, a seat component and a control that operatively supports the backrest component and the seat component on the base for synchronous movement between the vertical and resting. Accordingly, an apparatus that solves the aforementioned problems and has the aforementioned advantages is desired.

US 2002/0171277 A1 discloses a seat unit according to the preamble of claim 1.

The invention is set out in the independent claim.

These and other aspects, objects, and features of the present invention will be understood and appreciated by those skilled in the art upon study of the following specification, claims, and accompanying drawings.

The present invention can be carried out in various ways, and various embodiments according to the inventions will now be described, by way of example, with reference to the accompanying drawings, in which:

Fig. 1 is a perspective view of a seat unit embodying the present invention, with the seat unit including cross wires in a back and seat, forming a comfortable support surface;

Fig. 2 is a schematic cross sectional view showing the position of the cross wires in the seat and back of FIG. 1, the wire support elements being shown in continuous lines without a seated user, the wire support elements being shown in segment lines with a user sitting in a vertical position;

Fig. 2A is a view similar to fig. 2, but showing the chair with the user sitting upright in dashed lines and in a reclined position in dashed lines;

Fig. 2B is a schematic view similar to fig. 2A, but with the change in seat shape overlapping to eliminate confusion caused by a translation / rotation movement (up and forward) of the seat during recline;

Figs. 3-4 are plan and side views of the seat of fig. 1;

Figs. 5-6 are plan and side views of the seat frame of fig. 3;

Fig. 7 is a partially exploded perspective view of the corner section of the seat of FIG. 3; Figs. 8-10 are side, top and end views of a support shoe used to slidably support one end of one of the wires shown in FIG. 7;

Figs. 11-12 are plan views of two different wires used in the seat shown in FIG. 3;

Figs. 13-14 are side and plan views of a cover for the side sections of the seat structure shown in Figs. 5-6;

Figs. 15-16 are front and rear perspective views of the backrest shown in fig. 1;

Fig. 17 is a side view of the backrest shown in FIG. fifteen.

Fig. 18 is a side view of the lower seat control shown in FIG. 1.

Figs. 19-20 are cross-sectional views similar to fig. 18, but showing the cross-sectional components, fig. 19 along line XIX in fig. 33 and showing the uncoupled reinforcing mechanism, and showing fig. 20 the coupled reinforcing mechanism;

figs. 21-23 are cross-sectional views similar to FIG. 18, but showing the cross-sectional components, fig. 21 along line XXI in fig. 33 and showing the decoupled anti-kickback mechanism, and showing fig. 22 the backrest stop mechanism coupled to a first level of partial reclining of the backrest, and showing FIG. 23 the backrest stop mechanism coupled to a second level for no backrest recline;

Fig. 24 is a graph showing the different lines of support force of the backrest with respect to the deviation, depending on whether the reinforcement is decoupled or coupled and if the backrest stop is coupled for partial recline or to avoid any recline;

Fig. 25 is a graph showing the different mechanisms of resistance increase in a chair in which they selectively provide increasing amounts of energy as each successively couples;

Fig. 26 is an exploded perspective view showing a manual control located at the bottom of the seat for the backrest stop and booster mechanism;

Figs. 26A and 27A are similar to figs. 26 and 27, but showing alternative embodiments;

Fig. 27 is a cross sectional view taken along line XXVII in FIG. 33.

Fig. 28 is an exploded perspective view of the manual control of FIG. 26.

Figs. 29-30 are cross-sectional views of the manual control of FIG. 28, fig. 29 fully assembled, and fig. 30 exploded view;

Fig. 31 is an enlarged fragmentary view of the clutch and its engagement with the outer casing, showing the clutch in a locked position;

Figs. 31A and 31B are fragmentary enlarged views of a portion of FIG. 31l, a fig. 31A shows a locked position and fig. 31B shows a release position;

Figs. 32-33 are partial front and rear perspective views of the base and control of FIG. 18;

Figs. 34-35 are fragmentary plan and front views of the control shown in fig. 33;

Fig. 36 is an exploded perspective view of FIG. 33.

Fig. 37 is an enlargement of the energy increasing mechanism shown in FIG. 36; Y

Figs. 38-39 are cross sections taken along line XXXIX in fig. 33, and are side views of the control, seat and backrest, fig. 38 in a vertical position and fig. 39 a reclined position, figs. 38-39 similar to fig. 18, but being simplified to show the operation of the pivot joint during recline.

Figs. 40-42 are front perspective, rear perspective, and lateral views of a modified form of the chair of the present invention;

Fig. 43 is a perspective view of the lower seat control for the chair of FIG. 40.

Figs. 44-46 are a top perspective exploded view, a second top perspective view and a bottom perspective view of a portion of the control and related base components of the bottom of the seat of FIG. 43;

Figs. 47-49 are exploded perspective views of the bottom seat control of FIG. 43, figs. 48 and 49 show a manual control for adjusting the reinforcement and the backrest stop mechanism shown in fig. Four. Five;

Figs. 50-51 are fragmentary perspective and perspective views of the seat shown in FIG. 40;

Fig. 52 is a cross section showing the flexing of the wire support element for the wire support elements shown in FIG. 50, and fig. 52A is a similar view showing an alternative mounting structure;

Figs. 53-54 are exploded perspective views of the backrest shown in FIG. 40;

Figs. 55-57 are perspective views of the lumbar devices and their effect on the wire support sections;

Fig. 58 is a diagram showing the lumbar device of FIG. 57.

Fig. 59 is a perspective view of the chair of FIG. 40 with the lumbar device of FIG. 55 in a disabled storage position;

Fig. 60 is an exploded perspective view of the headrest assembly on the chair of FIG. 40;

Figs. 61-62 are an exploded perspective and exploded cross section of the headrest assembly of FIG. 60;

Fig. 63 is an exploded perspective view of the wire frame and seat support elements of FIG. 50, including depth adjustment hitch and release handle;

Fig. 64 is an enlarged top perspective view similar to FIG. 51, but which is centered in a front corner of the seat subassembly of FIG. fifty;

Figs. 65 and 66 are cross-sectional views taken perpendicularly through the hooking area of fig. 64, with fig. 65 showing a latching position and fig. 66 showing a disengaging position of the engaging element;

Figs. 67-69 are fragmentary views of the rear frame of fig. 53 and the side frame elements of fig. Four. Five; figs. 67 and 68 show the mounting of the vertical elements together; showing fig. 69 the complete set; Y

Figs. 70 and 71 are cross-sectional views showing a coupling configuration for coupling a damping assembly to the rear frame of FIG. 53.

A chair 20 (fig. 1) embodying the present invention includes a base 21, a seat 22, and a backrest 23, with seat 22 and backrest 23 operatively supported on base 21 by a bottom control mechanism seat 24 for synchronous movement when reclining backrest 23. During recline, control mechanism 24 moves and lifts seat 22 up and forward, so that backrest 23 (and the seated user) receives automatic a weight-activated backrest support force during recline. Advantageously, heavier seated users receive a greater backrest support force, thereby eliminating (or at least reducing) the need for them to adjust a tension device for backrest support when reclining in the chair. The seat 22 (and also the backrest 23) includes a very comfortable support surface formed by a locally compatible support structure (hereinafter called "a comfort surface") that adjusts to the changing needs of shape and ergonomic support of the user sitting when in a vertical position and in a reclined position. Specifically, the comfort surface changes shape in a way that keeps the user comfortably seated in the chair during recline, yet provides optimal localized ergonomic support for the changing shape of the seated user when the user's pelvis rotates during resting. Furthermore, the chair 20 avoids placing an uncomfortable lifting force under the knees and thighs of the seated user, by a good distribution of such forces on the knees and / or partially by flexing partially out of the way in the area of the knees. Furthermore, the comfort surfaces of the seat 22 and the backrest 23 create a changing cube shape (figs. 2A and 2B) that "grabs" a seated user and also actively distributes tension around the localized areas, such that the Seated user sits comfortably restrained in seat 22, and does not feel as if sliding down the seatback / reclining back and forth seat recline during recline, as described below.

The illustrated control mechanism 24 also has several advantages and aspects of the invention. Control mechanism 24 includes a "booster" mechanism 25 (fig. 19) that can be attached (with little effort) to provide even greater backrest support during recline, if the seated user desires additional support during resting. Advantageously, the control mechanism 24 has a slim profile and is very cost-effective to manufacture and assemble, so that it can be well integrated into chair designs that have a slim side profile. The combination of the comfort surface on the backrest 22 and the seat 3 (fig. 1) with the control mechanism 24 provides a surprising and unexpected result in the form of a very comfortable and well supported "movement" in all positions of the chair, even upright and reclined. The comfortable "movement" is at least partially due to the fact that, while the seat is raised during recline to provide a weight-activated backrest support force, with the seat 22 and backrest 23 surfaces dynamically changing so as to relieve pressure behind the seated user's knees. Furthermore, the comfort surfaces of the seat 22 and the backrest 23 also create a changing hub (see Figs. 2A and 2B) to support the pelvis when it "rolls" and changes shape during recline, which counteracts gravitational forces, making the body of the seated user want to slide down the reclined / inclined surface of the backrest 23 and slide forward out of the seat 22. In addition, the reinforcing mechanism 25 in the control mechanism 24 is very easy to engage or disengage, (almost like a toggle that turns on or off), making it more likely to be used. Furthermore, this allows the reinforcing mechanism 25 to be operated by an automatic panel and / or remote devices, including electronic, mechanical, and others. Advantageously, all the main components of the chair 20, including the control mechanism 24, are separable and recyclable, which facilitates the repair, and the promotion of components and processes that are environmentally friendly, while maintaining a low-cost assembly, efficient, with relatively few complex parts, and other competitive advantages.

Seat 22 (figs. 3-4) includes a molded perimeter frame 30 made of nylon or the like. The illustrated frame 30 is semi-rigid, but is capable of flexing and rotating a limited amount, such that the frame 30 yields and moves with a seated user reaching and reaching for items while doing work tasks. Frame 30 includes a U-shaped rear part with horizontal side sections 31 connected by a transverse rear section 32, and further includes a U-shaped front part 33 connecting a front part of the side sections 31. It is contemplated that the Perimeter frame 30 may be molded in one piece, or be a multi-piece assembly. The illustrated frame 30 defines a continuous loop, but it is contemplated that the frame could also be U-shaped with an open front, for example. The U-shaped front part 33 includes side sections 34 that connect to one end of the side sections 31 and extend downward and to the rear, and further includes a cross section 35 connecting the side sections 34. The U-shaped front part 33 forms a "U" when viewed from the front, and tilts down and back so that it leaves an open area upward in a front part of the perimeter frame 30 in a location corresponding to the lower part of the knees of a seated user. This allows the perimeter frame 30 to avoid putting pressure on the lower knees of a seated user during recline, despite the seat 22 being raised, as described below.

Side sections 31 include a series of notches 36 (six of such notches are illustrated) approximately 3 to 7 inches back from a front end of side sections 31, or more preferably 4 to 6 inches. The notches 36 create a flex point, which causes a front section 37 of the side sections 31 to flex downward when pressure is exerted on the front end of the side sections 31. For example, the front section 37 will flex when the front of the seat 22 is raised against the knees of a seated user and the user is raised, which occurs during the reclining of the backrest 23.

A pair of tracks 38 are attached to the bottoms of the side sections 31 toward the rear of the notches 36. The pair of tracks 38 are adapted to slidably engage a seat support structure to provide a depth feature adjustable in chair 20. However, it is noted that the present inventive concepts can be used in chairs that do not have a depth adjustment feature.

Each of the lateral sections 31 of the perimeter frame 30 (fig. 5) includes longitudinally extending recesses 40, respectively, on their upper surfaces to receive steel rods 42 (figs. 3 and 12). The lateral rods 42 elastically support and reinforce the lateral sections 31, in particular in the area of the notches 36. As illustrated (in Figs. 3-4), the recesses 40 are located mainly towards the rear of the notches 36, but also include a front portion that extends forward beyond the notches 36 to provide added elastic support for the side sections 31 at the notches 36. It is noted that the rods 42 may have different shapes or sizes, or be they can use multiple rods. Furthermore, different materials can be used in the rods 42, if desired, such as plastic or composite materials. However, the illustrated rods 42 are linear and made of "cold drawn spring steel" for optimum strength, low weight, long life and competitive cost. Furthermore, they are mechanically linked in position at their front and rear parts. It is contemplated that rods 42 could also be insert molded, snapped on, or otherwise secured in place.

The comfort surface of the seat 22 (fig. 3) (and of the backrest) is formed by individual support elements 45 with long parallel sections 51 and U-shaped ends 52 that slidably engage cavities 50 in the lateral sections 31 Thirteen cavities 50 are illustrated, but it is contemplated that they could be included more or less, depending on the design of the chair and the functional requirements of the design. Furthermore, the multiple cavities 50 could be replaced by continuous long channels formed longitudinally along the side sections 31, if desired. Each cavity 50 includes pairs of inwardly facing openings 51 '(FIG. 5) with an "upward overhang 51" formed between the openings 51'. The ends 52 of the eight front support elements 45 are located in and directly engage in a sliding manner with the eight front cavities 50 for limited movement in and out, while the ends 52 of the five rear support elements 45 they are supported by supports 53 in the five posterior cavities 50, as explained below. The interior surface of the cavities 50 (ie, the "upward" projection 51 "formed between the openings 51 ') forms a stop to limit inward sliding movement of the ends 52 of the support member 45. By doing this downward flexion of long sections 51 is limited with a "sling" type action when a person sits on the comfort surface of seat 22. In particular, this results in a "smooth" stop action when a seated user achieves maximum flexing of long sections 51. Part of the reason for the "soft" stopping action is inward flexing of side sections 31 when ends 52 contact bottom in cavities 50, but also part of the "soft" stopping action is due to the independent action of the individual support elements 45 and the paired arrangement of the long sections 51 on the support elements 45. By this arrangement, a seated user remains comfortable and does not feel an abrupt and sudden stop that is uncomfortable, even though the seat 22 is kept in a maximum depression.

The support elements 45 (fig. 7) are cold drawn spring steel rods (fig. 11) having a circular cross section. The rods (ie, the support members 45) are bent into a rectangular loop with relatively roughly bent corners, and include parallel / linear long sections 51 and flat / short end sections 52. The illustrated end sections 52 they have relatively sharply bent corners so that they form relatively square U-shaped configurations. In addition, one of the illustrated end sections 52 has opposite ends of the wire that butt but are not joined. It is contemplated that the adjoining ends of one end section 52 could be welded together, if necessary, but this has not been necessary in the current chair 20, particularly when supports 53 are used, as explained below. It is also contemplated that individual linear rods could be used in place of the support member 45, which is a rectangular loop shape with long parallel sections 51, if desired. In such a case, the ends 52 could be L-shaped or hook-shaped to engage the "up" protrusion in the cavities 50 for limited inward movement when a person sits on seat 22. However , the interconnection of Adjacent pairs of long sections 51 through end sections 52 can provide additional stability and "coordinated" cooperative movement in pairs that are believed to have beneficial effects. In particular, the five rear support elements 45 with supports 53 are subjected to considerable movement and flexion when a seated user reclines and / or moves around in chair 20, so that supports 53 with sections of Coupled wires 51 are desirable with the five support elements 45.

As noted above, the five rear support elements 45 (fig. 7) include support shoes 53 (also called "supports" herein) (figs. 8-10) that are coupled to the end sections 52. Support shoes 53 are made of acetal polymer and are shaped to operatively fit within cavities 50 for oscillating sliding movement (interior and exterior) in a transverse direction when a seated user moves around in chair 20 and when Long sections 51 of the support member 45 flex. Support shoes 53 include a U-shaped channel 54 shaped to co-receive U-shaped end sections 52. Support shoes 53 may include a friction tab at locations 55 for snap-fit engagement in the U-shaped ends 52, if desired, although a friction flange is not required by itself when providing a top cap that captures support shoes 53 in cavities 50. In particular, support shoes 53 retain together end sections 52 having the ends of the wire touching, even when the adjacent ends of the wire are not directly bonded together by welding.

The right and left top covers 57 (figs. 13-14) are screw-attached, heat-staked, or otherwise coupled to the side sections 31. The top covers 57 (fig. 7) include a body 58 with a shape to cover cavities 50 and operatively hold support shoes 53 in place. A rear of the body 58 extends laterally and potentially includes a slot 59 to better cover one of the posterior cavities 50 while allowing the posterior wire section 51 to flex freely (Fig. 7). It is contemplated that the side sections 31 and the upper covers 57 will be made of nylon, and the support shoes 53 made of acetal, since these materials have a very low coefficient of friction when they are coupled together. Furthermore, the openings 51 '(fig. 7) are oversized to be larger than the diameter of the long sections 51 of the rod support elements 45, so that there is no resistance during bending of the support elements 45 and the simultaneous movement of the support shoes 53 in the cavities 50.

The illustrated seat 22 (fig. 1) is covered with a fabric 60, and potentially includes a fine foam top or PET fiber non-woven cushion under the fabric 60 in both seat 22 and backrest 23. However, it is contemplated that seat 22 and / or backrest 23 may not require a foam cushion since, based on the evidence, the present seat 22 is so comfortable that a cushion is not necessary. Furthermore, the space between the wire sections 51 allows the construction to breathe, so that a seated user sweats while resting in the chair 20, which can also be a competitive advantage. A cinch or thin liner pad could also be used under the fabric for aesthetic purposes, if desired.

The present seating arrangement 22 offers several advantages. Mounting is easy, and it is difficult to improperly mount the seat. By the present arrangement, each different pair of wire sections can flex different amounts, and in addition, each long section 51 on a given support member can flex more or less (and can flex in a different direction) than the other long section 51 in par. The recesses 50 engage the support shoes 53 and limit their movement such that they in turn limit the flexing of the long sections of wire 51 to a maximum amount so that the support surface cannot flex "too much far". Based on the tests, the maximum flex limit provided by cavities 54 is a soft limit, such that a seated user does not feel a sudden stop or "jerk" when maximum flex is achieved. It is noted that all of the long wire sections present 51/52 have the same diameter and shape, but could have different diameters, stiffnesses, or shapes. The individual long wire sections 51 are displaced to support the body of a seated user along discrete and independent lines of support, with the long wire sections 51 moving in and out to fit the body and support the user. Specifically, when a seated user reclines, the wires move and flex to create a new variable "support cavity" for the seated user. Fig. 2 shows the comfort surface 60 of seat 22 as being relatively flat (i.e. position P1: see solid lines) when no user is seated leaning on seat 22. (i.e. long wire sections 51 of the elements support 45 of seat 22 lie in a generally horizontal common plane.) When a seated user sits in chair 20 in a vertical position, comfort surface 60 flexes to a new shape (i.e., position P2 (see dashed lines), which includes a "upright" support cavity 63 formed by (and receiving and supporting) the protruding bone structure, muscle, and hip tissue of a seated user. As the seated user reclines backrest 23 into a fully reclined position (Fig. 2A), comfort surface 60 flexes to a new shape (ie, position P3; see dashed lines), which includes a newly formed "recline position" support cavity 65, formed by (and receiving and supporting) the protruding portion, muscle, and hip tissue of a seated user. In particular, the support cavity 65 formed in the seat 22 while in the recline position (fig. 2B) is located rearward of the support cavity 63 formed in the seat 22 when it is in the recline position (see Fig. 2B, where a seat shape in the upright and reclined positions overlap to better show the shape change). This is caused by a rolling movement of the hips during recline. The long sections 51 of the support elements Rod 45s are independent and provide localized and dynamic freedom of movement capable of comfortably accommodating the rolling activity of the hips of a seated user in a new and unobvious way not previously seen in work chairs.

The backrest 23 (fig. 2) also undergoes a shape change, as shown by the comfort surface 66 in the P1 position without tension (not stressed, without sitting user), the flexed comfort surface 66 in the vertical tensioned position P2 ("vertical position" with the user seated), and the flexed reclined comfort surface 66 in the tensioned reclined position P3 ("reclined position" with the user seated) (Fig. 2A).

The pairs of long wire sections 51 act in a coordinated distributed dynamic manner (mainly in the vertical direction) which provides an optimal comfort surface. This is a result of the restricted / limited movement of the support shoes 53 in the adjacent pairs of the long sections 51 of the rod support elements 45 and it is also the result of the fabric 60 as it extends and covers the sections However, it is noted that extremely comfortable support can be achieved even without the fabric 60, because the long sections 51 are flexed in a way that does not squeeze or stick to the seated user, since the shape of the body support cavity changes.

It is noted that the long sections 51 in the seat 22 flex and move to provide primarily vertical support, but that some of the long sections 51 may have a horizontal or tilting component and / or may provide a horizontal force component or tilted to a seated user. In particular, long sections 51 located in a front part of the "recline" support cavity 65 (see wires 51A) tend to resort to any depression in the flesh of a user sitting in a front part of the area of the hip protruding from the seated user (ie behind the thighs of the seated user and in front of the seated user's "main" hip area) which tends to hold firmly the user seated in seat 22. This occurs regardless of the location of the depression in the meat of a particular seated user, due to the plurality of independently flexible long sections 51 in the seat 22. This additional holding power appears to be important in preventing seated users from feeling that they will slip. down on a sloping backrest (for example, during recline) and forward and out of the seat. The present inventors believe that this advantage, albeit subtle, is a very important and significant advantage of the chair 20. It should be noted that, even with a fabric cover, there may be a horizontal component of the force provided by the long sections 51, limited only by the movement of the long section 51 under the fabric, the stretchability of the fabric, the movement of the support shoes 53, and the forces generated by the rolling action of the hips of the seated user.

The operation of the seat 22 is illustrated in figs. 2-2B. Fig. 2 shows the bending of a center of the long sections 51 of the support element 45 between the state without tension (that is, without a seated user; see solid lines P1), and a state of tension (that is, with a seated user ; see dashed lines P2) (both in a vertical position of chair 20). Fig. 2A shows chair 20 with a user sitting in chair 20 in the vertical position (solid lines) and a reclined position (dashed lines). Fig. 2B is a schematic view intended to show the change in shape of the comfort surface of seat 22 between the vertical position (see solid lines P2) and reclined position (see broken lines P3). In fig. 2B, seat 22 is compared as if it did not move forward during recline, to better show the change in the shape of the "cavity" in seat 22, where the seated user's hips are located. However, it is observed that the seat 22 moves forward during recline in the present chair 20.

Fig. 7 shows some of the support elements 45 with long sections 51 without tension (that is, they are in an external position in their respective cavity 50), and shows some of the rod support elements 45 with the wires 51 flexed ( that is, see support pads 53 at location "B" that are located inwardly in their respective cavity 50). Fig. 7 also shows some of the support shoes 53 in exploded view outside the cavities 50 and pre-attached to the ends of the rod support elements 45 (see location "C"). The support shoes 53 are ready to lower, being inserted into the cavities 50, which illustrates a first mounting technique. Fig. 7 also shows one of the support shoes 53 positioned in a cavity 50, with the associated rod support element 45 positioned above it and ready to move down in engagement with the recess in the support shoe 53 (see location "D"), illustrating a second mounting procedure.

The backrest 23 (figs. 15 to 17) is similar to the seat 22. Therefore, a detailed description of the backrest 23 is not required for an understanding by a person skilled in this technique, since it would be very redundant. However, the following is a description that is sufficient for an understanding of the present invention as used in the backrests, in view of that explained with respect to the seat 22 above.

Briefly, the backrest 23 (figs. 15-17) includes a rear perimeter frame 70 comprised of L-shaped side frame elements 71. The upper and lower transverse frame elements 72 and 73 are attached to the frame elements laterals 71 to form a semi-rigid perimeter. Frame 70 can be single-piece or multi-piece. An additional cross frame element 72A (fig. 1) can also be added, if required for strength and stability. Side frame elements 71 include lower sections extended forward 74 extending below the lower cross frame member 73. The lower sections 74 are pivoted to a seat support 122 of the control mechanism 24, at position 75, and pivoted to a flexible arm portion of the control mechanism 24 at position 141, as described below.

As with seat 22, rear side frame elements 71 include cavities 77 (see seat frame cavities), covers 77, covering cavities 77 (only one left cover 77 'shown), and support elements 78 (similar to seat support elements 45) as cold drawn spring steel wires with long sections 79 (similar to long seat sections 51). Several of the support elements 78 have ends that are operatively supported by support shoes 80 (similar to support shoes 53). In particular, the illustrated rear support elements 78 come in two different lengths, because the back 23 has a smaller upper width and a larger lower width. (See Fig. 15 and note the change in the position of the cavities 77 in a median area of the side frame elements 71.) The upper half of the side frame elements 71 includes a plurality of U-shaped cavities 81 for receiving a wire 79 without a support shoe 80. An upper edge of the upper frame member 72 is U-shaped and tilted back for increased neck support and comfort for the seated user. Strips of wire 83 extend from the upper corners of the rear frame 70 to a central point between the shoulders of a seated user, and then extend downward to connect to a center of the lower cross member 73. When tensioned, the Strips of wire 83 cause the comfort surface of the backrest (ie, the support elements 78) to take an initial concave shape (sometimes called the "PRINGLES potato chip shape"). This concave shape increases comfort by providing a more comfortable "cavity" in the backrest 23 so that a seated user adapts well when initially sitting in chair 20.

An adjustable lumbar support 85 (Figs. 15 to 17) is provided in the backrest including a pair of bodies 86 slidably connected to an inner flange 87 in each of the side frame elements 71. The bodies 86 can (or no) be connected by a transverse element. The bodies 86 are located behind the wires 79 adjacent to the side frame elements 71 and the wires 79. Handles 88 extend from the rear of the bodies 86 so that a seated user can reach behind the backrest 23. Each one of the bodies 86 includes a flange 90 that mates with a section of the wires 79 when the wire extends in a direction outward of the cavities 77. By adjusting the bodies 86 vertically, the flanges 90 move behind of the different wires 79, causing a different level of support (since an effective length of the supported wires is less). Alternatively, the flange 90 can be physically coupled and bend the wires 79 when vertically adjusted, if desired. Fig. 17 also shows maximum backward flexion of wires 79, as shown by line 95.

The present control mechanism 24 (fig. 18) includes a stationary base bracket 121 that forms a part of the base 21. Seat 22 includes a seat bracket 122, and the backrest 23 includes a backrest bracket 123. The brackets Seat and backrest 122 and 123 are operatively attached to base support 121 as follows. Base support 121 includes an upwardly facing recess 115 partly covered by plate 115A. The recess 115 forms a first cavity 116 to receive the stiffening mechanism 25. The recess 115 also forms a second conical cavity 117 that extends vertically downward through the base bracket 121 to receive the conical upper section 118 of a post height adjustable 21A. The illustrated base 21 (fig. 1) includes a bushing on a lower post 21A, radially extendable side sections extending from the bushing, and wheels at the ends of the side sections to support the chair 20. A lockable air spring It is incorporated into the post 21A to provide counterweight support during height adjustment. Post 21A (fig.

18) includes a vertically actuated release button 21b located on an upper part of the base support 121. At this location, the release button 21B can be actuated by a handle (not shown) operatively attached to an upper or lateral part of the support Base 121, with the handle pivotably or rotatably movable to selectively cause the handle to depressively engage release button 21B and release the air spring for chair height adjustment. Although a particular base is illustrated, it is specifically contemplated that a variety of different chair bases can be used in combination with the present chair 20.

The seat support 122 (Fig. 36) is operatively supported on the base support 121 by a front leaf spring 123 'and by a pivot mechanism 124 spaced to the rear of the leaf spring 123'. Specifically, the front leaf spring 123 'includes a central portion 125 supported on and coupled to an inclined front surface 126 (oriented approximately 45 °) of the base bracket 121 by means of threaded clamps, and includes arms 127 which are shaped Barrel or spherical supports 128 at each end that slideably and rotatably fit into the cylindrical cavities 129 in the side members 130 of the seat support 122. The supports 128 are barrel-shaped rather than cylindrical in shape, so that the Supports 128 allow some non-axial rotation and axial slip when arms 127 are flexed, which helps to reduce high stress areas and allow a wider range of motion during recline. However, it is contemplated that different support arrangements are possible that will still meet the needs of the present inventive concepts.

The lateral elements 130 are rigidly interconnected by a transverse beam 131 (fig. 36). Pivot mechanism 124 includes one (or more) pivot arms 132 that are pivotally supported at one end in the base bracket 121 by a pivot pin 133, and are pivotally connected to a center of cross beam 131 at its other end 134 by pivot pin 134 "and pin supports 134 '. Pin supports 134 'are attached to a cross piece 131, such as by screws. Pivot pin 133 is keyed to arm 132 so that pivot pin 133 rotates with movement of the seat (ie, during recline). Thus, the direction and orientation of movement of the seat support 122 (and the seat 22) is driven by the linear movement of the support ends 128 such as the arms 127 or the flexing of the leaf spring 123 '(which forms an angle 45 ° forward and up; see R1 in Fig. 38), and by the arched movement of pivot arm 132 in pivot mechanism 124 when pivot arm 132 rotates (starting at a 45 ° angle and ending near an angle of 10 °, when the backrest 23 approaches a fully reclined position; see R2 in fig. 38). The displacement distance from the front of the seat 22 is preferably about A to 2 inches, or more preferably it is about 1 inch up and 1 inch forward, but it can be made greater or less, if desired. In addition, the vertical component of the seat back travel distance is approximately A to 1 inch, but can also be made larger or smaller, as desired. It should be noted that the vertical component of the seat movement is the component that most directly affects the potential energy stored during reclining in the chair 20. In other words, the greater the vertical component of the seat (that is, the amount of vertical lift) during recline, the greater the weight-activated support received by the user seated during recline.

The vertical backrest support 123 (fig. 36) includes side sections 135 pivoted into the side elements 130 of the seat support 122 in the pivot position 75, which is approximately halfway between the location of the pivot 129 and the pivot 134 The illustrated pivot location 75 is approximately the same in height as the supports 128 (see FIG. 19), although it could be located higher or lower, as desired, for a particular chair design. A rear leaf spring 137 (fig. 36) includes a central portion 138 attached to a forward sloping surface 139 at the rear of the base support 121, and includes arms 140 with the supports being spherical or barrel-shaped 141 pivotally and slidably engaged in a cylindrical cavity 142 in the lateral sections 135 of the backrest in a vertical position 123. The rear surface 139 is approximately oriented at an angle 30 ° forward with respect to the vertical, which is an angle opposite to backward angle of the front surface 126. As a result, since the lateral sections 135 of the rear spring 137 flex during recline, the rear supports 141 are forced to move forward and downward in a direction perpendicular to the inclined surface posterior 139 (see addresses R3 and R4, fig. 38). Therefore, pivot 75 drives seat 22 forward along lines R1 and R2 during recline, and in turn a recline motion of backrest 23 causes seat support 122 to move forward and upward. . As noted above, the movement of the seat support 122 is controlled in the front area by flexing the ends of the front spring 123, which moves the supports 128 in a linear direction at an angle of 45 ° (up and forward in direction "R1"), and is controlled in the rear area by rotating pivot arm 132, which is arc-shaped (up and forward along path "R2 °). Pivot arm 132 is in a angle of approximately 45 ° when in the vertical rest position (figs. 19 and 38), and is at an angle of approximately 10 ° when in the fully reclined position (fig. 39), and moves in an arc shape between the two extreme positions during recline. The movement of the seat support 122 causes the pivot location 136 (fig. 38) to move forward along a curvilinear path. As a result, the upright backrest 123 rotate a mainly backward and downward during recline (see line R3), but also lower lateral section 74 moves forward with synchronous movement coordinated with seat 22, as shown by arrows R1-R2 (for the seat 22) and R3-R5 (for backrest 23) (fig. 38).

Specifically, during recline, a seat support backrest 122 initiates its movement by rising as fast as a front part of the seat support 122. Upon further recline, the seat support backrest 122 rises at a slower continuous speed (as the arm 132 approaches the 10 ° angle), while the front of the seat support 122 continues to rise at the same speed. The backrest 23 (i.e., the upright backrest 123) moves angularly down and forward during recline. Therefore, the seat support 122 moves synchronously with the vertical backrest 123, but with a complex movement. As a person skilled in the art of chair design will understand, a wide variety of movements are possible by changing the angles and lengths of the different components.

Booster mechanism 25 (fig. 19) forms an energy adjustment mechanism in the form of a torsion spring 150. Torsion spring 150 is mounted on pivot pin 133 to seat support 121. Torsion spring 150 it includes an inner ring 151 (fig. 37) keyed to the pivot pin 133, an elastic rubber ring 152, and an outer ring 153 with an arm 154 extending radially outward. An actuator in the form of a stop member 155 is pivoted to the base bracket 121 by a pivot pin 155 '(and is keyed to the pivot pin 155') and includes a stop surface 156 that can be moved to engage or selectively disengaging arm 154. When stop element 155 is moved to disengage stop surface 156 from arm 154 (FIG. 19), torsion spring 150 moves freely, and does not add any deviation to control 120 during resting. However, when the stop member 155 is moved to engage the stop surface 156 with the arm 154 (FIG. 20), the outer ring 153 is prevented from moving during recline. This causes the torsion spring 150 to stretch and tense during recline, since pivot pin 133 does not rotate during recline, such that torsion springs 150 "boost" the amount of energy stored during recline, thereby increasing the amount of support received by a user seated during recline. It is envisaged that the torsion spring 150 will be made to add approximately 15% to 20% of the deflection force during recline, with the remainder of the deflection force being supplied by flexing the leaf springs 123 and 137 and by the energy stored by lifting the seat support and the user seated during recline. However, the strength percentage can, of course, be changed by design to meet certain functional and aesthetic requirements of certain chair designs.

In operation, when the booster mechanism 25 is "off" (FIG. 19), arm 154 moves freely when a seated user reclines in the chair. Therefore, during recline, as the seat lifts and lifts the seated user, the leaf spring flexible arms 127 and 140 123 'and 137 flex and store energy. This results in the seated user receiving a first level of backrest support during recline. When additional support is needed (ie, the equivalent of an increase in spring tension to support the backrest in a traditional chair), the reinforcing mechanism 25 engages by turning the stop 155 (fig. 20). This prevents arm 154 from moving, although arm 132 causes pivot pin 133 to rotate. Therefore, during recline, the rubber ring 152 of torsion spring 150 stretches, creating additional support for the user seated during recline. In other words, the support provided to the backrest 23 during recline is "reinforced" by the engagement of the reinforcing mechanism 25.

It is contemplated that several independent torsion springs 150 may be added to the pivot axis 154 ', and that they may be coupled in sequence (eg, having their respective stops 155 engaged at slightly different angles). This would result in increased backrest support, by engaging the additional torsion springs. (See Fig. 25) In another alternative, it is contemplated that a single long rubber ring 152 could be used and anchored to the pivot pin 133 in a single location, and that several different outer rings 153 and arms 154 (positioned of side by side on a common axis). By attaching additional arms, the torsion force of the torsion spring would increase at a higher speed during recline. It is also conceived that the stop 155 could have steps, like the stop 205 (fig. 21), so that the "reinforcing" torsion spring 150 engages and becomes active at different angular points in time during resting. There are also various other provisions and variations that a person with ordinary knowledge will understand and be able to make from the present disclosure. These additional concepts are intended to be covered by the present application.

There is a stop pin 290 (fig. 37) on the arm 132, and a stop 291 on the outer ring 153 of the torsion spring 150. The coupling of components 290 and 291, and also the coupling of the arm 132 with the base support 121 results in a positive placement of the backrest 23 in the vertical position. The rubber ring 152 can be pre-tensioned by locking the pin 290 and the stop 291. Thus, when the stop element 156 is engaged, this preload on the rubber ring 152 must be overcome before the backrest recline starts. 23. This results in high pre-tension (see fig. 24) each time the stop element 155 is engaged (see fig. 20). In an alternative construction, a stop pin 290 'is located on the arm 132 and positioned to abut a surface on the chair control base support 121 as a way of adjusting the vertical position of the backrest 23.

There is a backrest stop 205 (fig. 21) formed in the stop element 155. The backrest stop 205 is keyed directly onto the pivot pin 155 'so that it moves with the pivot pin 155'. There is no torsion spring element in the backrest stop 205 illustrated. Arm 132 includes a lever 202 with a stop surface 203 that forms a back stop mechanism. A backrest stop 205 is pivoted to pivot pin 155 'in a position adjacent to reinforcing stop element 155. Backrest stop 205 includes a first stop surface 206 and a second stop surface 207.

A manual control mechanism 220 (fig. 26) includes a selector device 227 mounted on the base support 121 below the seat support structure122. Selector device 227 is operatively connected to pivot pin 155 'as indicated below to move reinforcement stop 155 and backrest stop 205. Backrest stop 205 does not engage the stop surface 203 of lever 202 when the manual control mechanism 220 for the reinforcing mechanism 25 and the backrest stop 205 are in an "initial" decoupled position (figs. 19 and 21). The stop element 155 of the reinforcing mechanism 25 engages and activates the torsion spring 150 when the selector device 227 is moved to a first adjustment position (fig. 20). In the first position, the stop surface 203 is not yet engaged (Fig. 20). However, when control 220 is moved to a second adjusted position (FIG. 22), the stop surface of the backrest stop 206 engages the stop surface 203 of the lever 202, and the backrest 23 is limited to only one third of its maximum angular recline. (Backrest stop 205 may, of course, have additional intermediate steps if desired.) When the selector device 227 is in a third adjusted position (FIG. 23), the stop surface of the backrest stop 207 engages with the stop surface 203 of the lever 202, and the backrest 23 is limited to zero recline. The effect of these multiple positions of selector device 227 is illustrated by lines labeled 211 through 214, respectively, in the graph of FIG. 24.

The combination of the reinforcing mechanism 25 and the backrest stop 205 gives rise to a unique adjustable control mechanism, as illustrated in FIG. 24. Literally, the device combines two functions in a whole new way, being a single device that selectively provides (in a single element) a backrest stop function (i.e. the backrest stop mechanism 202/205) and also a rear tension adjustment function (i.e. the mechanism reinforcement 150/155).

It is contemplated that pivot pin 155 'can be extended to have an end located on an edge of seat 22 below or integrated into seat support 122. In such a case, the end of pivot pin 155' would include a handle for gripping and rotate pivot pin 155 '. However, the selector device 227 of the manual control mechanism 220 (figs. 26-27) can be placed anywhere on the chair 20.

A manual control mechanism 220 (fig. 26) includes a Bowden cable 251 having a sleeve 221 with a first end 221 'attached to the base bracket 121, and an internal telescopic cable 222 (fig. 27) that can move within the sleeve 221. A section of wheel 223 is keyed or otherwise coupled to pivot pin 155 'of the backrest and backrest stop mechanism, and one end 224 of cable 222 is tangentially attached to a perimeter of the section of wheel 223. (Alternatively, if the diameter of the pivot pin 155 'is large enough, the end of the cable 224 can be connected tangentially directly to the pivot pin 155'). Optionally, a spring 225 can be used for deflection of the wheel section 223 in direction 225 ', pulling the cable in the first direction 225. However, spring 225 is not required when cable 222 has sufficient strength to push telescopically as well as to stretch. Cable sleeve 221 includes a second end attached to seat bracket 122, such as at the end of a fixed rod bracket 226 extending from seat bracket 122. A selector device 227 is coupled near one end of the rod bracket 226 for cable 222 operation to select different stand / stop conditions.

The selection device 227 (fig. 28) works in much the same way as a shift lever found on a bicycle handlebar to shift gears on the bicycle. The selector device 227 is also similar to the lumbar force adjustment device shown in patent 6,179,384 (minus gears 56 and 56 '). It is noted that a patent entitled "FORCE ADJUSTMENT DEVICE", issued on January 30, 2001, Patent No. 6,179,384, discloses a clutch device of interest, and the entire contents of Patent 6,179,384 are incorporated herein by reference in its entirety in order to disclose and teach the basic details of a wedge clutch and its operation.

The illustrated selector device 227 (figs. 28-30) includes a housing 228 coupled to the rod holder 226 with an inner ring section 229 attached to the rod, and an annular cover 230 rising from the ring and forming a laterally open cavity 231 around ring 229. Retaining recesses 237 are formed around an inner portion of cover 230. A one-piece plastic molded rotary clutch member 233 that includes a hub 242 is positioned in cavity 231 and includes a first section 234 attached to the end of cable 221 ". Rotary clutch member 233 further includes a clutch portion 235 formed integrally with bushing 242. A handle 236 is rotatably mounted to one end of bracket 226 and includes protrusions 238 which engage the clutch 235 to control engagement with the retaining recesses 237, as follows.

Clutch portion 235 (fig. 28) includes one or more side sections 240 (preferably at least two side sections 240, and more preferably a uniformly circumferentially symmetrical number of side sections, such as the six illustrated side sections) having a first elastic section 241 that slopes from bushing 242 to an elbow 243 that is in contact with retaining recesses 237, and a second section 244 that extends in a reverse direction from the end of first section 241 to a free end 245 located between bushing 242 and retaining recess 237. Each free end 245 includes a hole 248. Handle 236 includes a section adjacent to clutch 246 that supports protrusions 238 at a location where each protrusion 238 engages to hole 248 at associated free end 245 of each side section 240. Due to angle of first sections 241 (fig. 31A, see arrow 280) relative to the inner surface of the housing defining the retentions 237, the first sections 241 interlock with the retaining recesses 237 against deflection of the spring 225 as reported by the tension in the cable 222 (see arrow 281), preventing movement of clutch 235 when it is deflected in direction 249 (fig. 31) by bushing 242. Therefore, when handle 236 is released, clutch 235 locks again against the force 281 of spring 225 (fig.

27) as communicated by cable 222 to clutch 235. However, when grip 236 is grasped and moved in the direction of rotation 283 (FIG. 31A) with respect to housing 228, the protrusions on grip 238 stretch the second section 244 to thereby stretch the first and second sections 241 and 244, so that the rotating member 230 (and the clutch 231) rotates. When the handle 236 is moved in a direction of rotation 282 (FIG. 31A), the projections of the handle 238 push the second section (s) 244 at a low angle to the retention recesses 237, so that the second sections 244 (and the first sections 241) exit outside and above the retention recesses 237 (fig. 31B), allowing the rotating element 230 (and the clutch 231) to move adjusting in direction 281 Thus, the present arrangement allows adjustment in any direction, but interlocks and prevents unwanted adjustment in a particular direction against a spring deflection force.

It is observed that the actuation of the reinforcing mechanism 25 and the backrest stop 205 is carried out in a particularly simple way, since the actuation action does not require overcoming the resistance of a spring or overcoming any friction force caused by spring 150. In addition, the actuating action does not require movement that results in energy storage (ie, it does not require compression or tension of a spring). In this way, a simple battery powered DC electric motor or a switch controlled solenoid will operate to drive the booster mechanism 25 and / or the backrest stop 205. FIG. 26 illustrates a housing 300 that supports a battery assembly and an electric rotary motivator (such as a DC motor), and includes an end-mounted switch. Fig. 27A illustrates a linear motivator 301 operatively connected to cable 222, and also illustrates a rotary motivator 302 connected to shaft 155 '. Since the movement of the booster mechanism 25 and the backrest stop 205 requires only a very small amount of energy with minimal friction drag, it can be accomplished without the need for a large power source. Therefore, a small battery-operated device would work well for a long time before needing to recharge its battery.

The control mechanism 24 illustrated above has front and rear springs used as flexible weight bearing elements to support a seat and backrest for modified synchronous movement, and has a pivoted link / arm that facilitates the direction of movement of a backrest of the seat. However, the present arrangement may also include rigid arms that pivot to base support 121, or may include any of the support structures shown in United States Patent Application Publication No. 2004/0051362, published on March 18, 2004, entitled "MOVEMENT CONTROL SEAT UNIT", all of the content of which is incorporated herein in its entirety. In addition, a "boost" mechanism 25 provides increased deflection support during recline when a stop is engaged. However, it is contemplated that a continuously adjusting deflection device, such as a threaded element for adjusting a spring or cam tension could be used in place of the booster mechanism 25.

Since seat support 122 is raised during recline, potential energy is stored in recline. Thus, a heavier seated user receives more support during recline than a light seated user. Furthermore, as a seated user moves from the reclining position to the vertical position, this energy is recovered and therefore facilitates movement to the vertical position. This provides a weight activated motion seat, where the seat is lifted during recline and thus acts as a weight activated motion control. (That is, the greater the weight of the seated user, the greater the deflection support to support the user during recline.) It is observed that a variety of different structures can provide weight-activated control, and still be within a scope of the present invention.

A modified chair or seat unit 20B (Figs. 40-42) includes changes and improvements to chair 20. In order to minimize redundant explanation and facilitate comparison, components and features of chair 20B similar and identical to those of chair 20 will be identified using many of the same identification numbers, but with the addition of the letter "B".

Chair 20B (fig. 40) includes a base 21B, a seat 22B, and a backrest 23B, with seat 22B and backrest 23B operatively supported on base 21B by a control mechanism 24B at the bottom of the seat for movement synchronous during backrest recline 23B. As with chair 20, during recline of chair 20B, control mechanism 24B moves and lifts seat 22B up and forward, so that backrest 23B (and the seated user) automatically receives a Backrest supporting force activated by weight during recline. The seat 22B (and also the backrest 23B) includes a highly comfortable support surface formed by a locally compatible support structure (hereinafter referred to as "a comfort surface") that adjusts to the changing needs of shape and ergonomic support of the user sitting, both when in a vertical position and in a reclined position. Specifically, the comfort surface changes shape in a way that retains the user sitting comfortably in the chair during recline, while at the same time providing optimal localized ergonomic support for the changing shape of the seated user when the pelvic bones The user rotates during recline. Furthermore, the chair 20B avoids placing an uncomfortable lifting force under the knees and thighs of the seated user, by the good distribution of such forces on the knees and / or the partial flexion outwards in the knee area. Furthermore, the comfort surfaces of the seat 22B and the backrest 23B create a changing cube shape (similar to that shown in Figs. 2A and 2B) that "grabs" a seated user and also actively distributes tension around localized areas , such that the seated user feels comfortably retained in seat 22b, and does not notice that it will slide down the reclined / reclined backrest or forward, exiting the seat during recline, as described below.

The chair control mechanism 24B (fig. 43) includes a backrest / reinforcement stop selector device 227B with a handle 300 rotatable about a first axis 301 to selectively move the backrest stop and reinforcement mechanisms (see Figs 19-23) (components 156 and 205) between the multiple positions illustrated in Figs. 19, 20, 22, and 23. Control mechanism 24B further includes a second control device 302 with a radially extending lever handle 303 that can rotate about a rod 304 forming a second axis 304 '. The second axis extends parallel, but is spaced from the first axis 301. The handle 303 is made to be positioned adjacent to the handle 300, and includes a projection which engages the handle 300 to form a stop surface to limit subsequent rotation of the handle 303. At one inner end of rod 304 (fig. 48) is a radially extending finger 305. Base 21B (fig. 45) includes a removable air spring with self-locking 307 having two fixed tabs 308 for engaging a sheath on a cable sleeve and a laterally activatable lever 309 operatively engaging an internal release button 307 on the spring. A laterally activatable air spring, such as an air spring 307, is commercially available commercially and need not be described in detail in this application. (See Cho patent 6,276,756). A set of cables (fig. 48) includes a cable 310 connected at one end 311 to finger 305 and at the other end 312 (fig. 45) to lever 309. The set of cables further includes a sleeve 313 (fig. 48 ) which is connected to the base support 121B near the handle 303, and which extends to and is connected to the tabs 308 (fig. 45) on the air spring 307.

As shown in figs. 44-46, the base support 121B is inverted from the base support 121. Specifically, the base support 121B (fig. 46) includes a similar cavity and an internal structure and surfaces to support the levers, stops and reinforcing mechanisms within the base support 121B, similar to the base support 121. However, the front portion 116B of the cavity in the base support 121B opens downward, and the cover 115B attaches to a lower part of the support Base 121B. A vertical arm 315 (fig. 45) is attached to the stop member 155B and extends through an upper opening 155B in the base bracket 121B. One end 316 'of a cable 316 is connected to the arm 315 and extends to a tangential connection in the backrest / reinforcement stop selector device 227B (fig. 48), so that when handle 300 is rotated, the cable 316 it is stretched (and / or pushed) ... and, therefore, the stop element 155B moves to a selected position. (See Figs. 19, 20, 22 and 23).

The laterally extendable arms 127B of the front spring 123B '(fig. 47) include a tongue 320 which is non-removably snap-fitted to a spherical bearing 321. The seat support 122B (fig. 45) includes a pair of elements side frame members 322 and a cross piece 323 rigidly connecting the opposite side frame elements 322. Each side frame element 322 includes a bore 324, which, if desired, includes a support sleeve 325. Each of the Spherical supports 321 at the ends of leaf springs 123B 'rotatably and telescopically slidably coupled to sleeve 325 / bore 324 to accommodate nonlinear motion of spherical bearing 321 during backrest 23B recline. A hole 75B (fig. 47) receives a pivot pin that rotatably connects the respective side sections 135B of the upright backrest support 123B to the seat support 122B. A flange 327 forms a groove 328 along an upper part of the side frame elements 322.

Each seat 22B (fig. 43) includes a bracket 480 that forms a mounting receptacle 481 on the side frame elements of the seat 322 to receive and securely support an "L" shaped armrest support structure 482 (fig. .42) and a T 483 armrest.

Seat 22B is depth adjustable, and includes a pair of seat carriers 330 (fig. 45) connected to each side for sliding depth adjustment. Specifically, each of the seat carriers 330 includes a body 331 (FIG. 65) adapted to slidably engage an upper portion of the side frame members 322 of the seat support 122B, and further include a side flange 332 which It fits into and slidably engages slot 328 to provide a forward / reverse depth adjustment of seat 22B. Seat 22B is captured in seat support 122B due to flanges 332 of right and left seat carriers 330 facing in opposite directions. A series of notches 333 on the upper inner side of the seat carriers 330 are coupled by a hitch 334 mounted on the seat carriers 330, the hitch 334 being movable downwardly in a mating position to engage a notch 333 selected for clamp seat 22B at a selected depth position. Hitch 334 is movable upward to disengage notches 333, thereby allowing horizontal depth adjustment of seat 22B. It is contemplated that hitch 334 may have a variety of different constructions, such as a shovel mounted for vertical movement in seat 22B, or a bent wire rod that when rotated has end sections that move in and out of the coupling with the notches 333. It is contemplated that other latching and adjusting arrangements can also be constructed.

In the illustrated chair design, hitch 334 is double-sided (fig. 63) and is adapted to engage both sides of seat 22B to prevent unwanted angular translation and torsion and horizontal plane rotation of seat 22B. In other words, it is preferable that both seat carriers 330 are fixed to their respective side frame members 322 when engaged to provide a stable seating arrangement that does not torque or turn in an undesired unbalanced manner when a seated user is trying to rest.

Illustrated hitch 334 (fig. 63) is powered by a U-shaped bent wire actuator 334 ', which includes a cross grip section 470 that forms a grippable grip on the front section of seat 388, and includes a pair of legs 471 and 472. Each of legs 471 (and 472) (fig. 64) fits into a space between side wall 365 and side section 359 (and between side wall 366 and side section 359). from seat 22B. An annular groove 473 (fig. 64) is adjusted to fit into a notch 474 in a flange 475 between walls 365 and 366 to form a pivot for leg 471 (and 472). Hitch 334 pivots on a shaft 476, and includes a hitch end 477 shaped to move in and out of engagement with notches 333, and includes a second end 478 operatively connected to a rear tip 479 of leg 471 in the address "D". When the handle section 470 moves upward, the side legs 471 and 472 pivot on the flange 475, so that the tip of the leg 479 moves downward. When the tip of the leg 479 is moved downward, the latch element 334 pivots around the pivot 476 to lift the latch end 477 out of the notches 333. A seat depth 22B can then be adjusted. One or more elastic springs 480 (fig. 63) located between the cross handle section 470 and the front section of the seat 388 deflects the section 470 downward, causing the hooking tip 479 to reengage into a selected notch 333 when releases the grip section 470.

As noted above, the chair control mechanism 24B (Fig. 43) includes a backrest / reinforcement stop selector device 227B with a handle 300 rotatable about a first axis 301 to selectively move the backrest stop mechanisms / reinforcement (see figs. 19-23) (components 156 and 205) between the multiple positions illustrated in figs. 19, 20, 22 and 23. More particularly, a tubular support 340 (fig. 48) is attached to the outer side of the right side frame member 322. A support sleeve 341 is placed on the tubular support 340, together with a spring compression screw 342, a crown-shaped retaining ring 343 with pointed axial tips 344 and handle 300. A rod 345 extends from handle 300 through components 343, 342, and 340 into an interior of the side frame 322. Handle 300 includes teeth-shaped projections 346 (FIG. 49) that engage the axial tips 344 of retaining ring 343, and retaining ring 343 axially deflects in an outward direction of so that the tips 344 are continuously coupled to the projections 346. In addition, the retaining ring 343 is keyed to the tubular support 340 so that the retaining ring 343 cannot rotate, but is able to move tel axially scopically. The tips 344 and the projections 346 include inclined surfaces, so that during the rotation of the handle 300, the retaining ring 343 will move axially inward against the deflection of the spring 342, and will then snap back out when the tips 344 they fit between adjacent projections 346, thereby allowing rotation of handle 300 in directions 347. This arrangement causes handle 300 to move with a holding rotation. The illustrated arrangement includes four projections 346 on handle 300, and sixteen points on retaining ring 343, but it is contemplated that more or less of each can be used. It is contemplated that handle 300 may include markings 349 to identify its function, and that any of the forms of handle commonly used in the chair technique may be incorporated into the illustrated design.

A lever 351 (fig. 48) extends from an inner end of rod 345, and is operatively connected to one end 353 of cable 316. Recall that the other end 316 '(fig. 45) of cable 316 is connected to the arm 315 of the stop element 155B of the stop coupling element of the backrest and of the reinforcement 155B.

Seat 22B (Fig. 50) includes a seat frame 357 comprising an upper frame component 358 and lower right and left seat frame components 359 and 360 attached to the left and right sides of the upper frame component 358. The lower frame components 359 and 360 are directly connected to the top of the aforementioned seat carriers 330 (FIG. 45), or may be integrally formed to incorporate the features of the illustrated carriers 330. The support elements 45B (fig. 50) comprise individual wires with lower hooks formed at each end, as described below.

The lower frame components 359 and 360 (fig. 50) are mirror images of each other, and accordingly only the lower frame component 359 will be described. The lower frame component 359 is a molded plastic component having a lower wall 362, front and rear end walls 363 and 364, and three longitudinal walls 365-367. Exterior wall 365 forms an aesthetic and structural exterior surface. Intermediate wall 366 includes a plurality of aperture projections 368 for receiving screws (not shown) to join upper and lower frame components 358 and 359/360 together. Inner wall 367 includes a plurality of vertically open grooves 369 that extend from its top surface to approximately half its height, and further include parallel walls 370 and 371 that extend from wall 367 to wall 366 on each side of grooves 369. A recess or cavity 50B is formed between each of parallel walls 370 and 371 to receive end sections 52B, as described below. The inner side of the intermediate wall 366 forms a first stop surface 372 (fig. 52), and the outer side of the inner wall 367 forms a second stop surface 373 with an inclined ramp surface 374 extending inward and downward away from the second stop surface 373.

Each support element 45B (fig. 50) comprises a single wire of the same type of wire as the support element 45 described above. Each support member 45B has a long section 51B and has L-shaped downwardly shaped end sections 52B forming hooks. Long section 51B is linear and generally extends horizontally through a bottom of grooves 369 when it is in an installed position without a user adjustment on seat 22B. End sections 52B are linear and extend downward into cavities 50B. Being in an installed position without a user adjustment on seat 22B (see solid lines in FIG. 52), end sections 52B abut the outer (first) stop surface 372, causing the long wire section 51B have a slight downward tilt in its mid zone at position 374 '. This provides a pretension and preform on the wire support member 45B. When a user sits in seat 22B (see dashed lines in FIG. 52), long section 51B folds until end sections 52B engage the inner (second) stop surface 373. This further limits more inclination or curvature of long section 51B. Furthermore, the inclined ramp surface 374 provides additional support to the end parts of long section 51B, towards the inside of end sections 52B, so that the effective length of long section 51B is reduced. This results in the support member 45B having a preset maximum bend that is limited by the inner stop surface 373 (i.e., a sling-like effect), and further is limited by a shorter effective length of the 51B long wire (which feels stiffer). Both circumstances cause smooth bottoming when the wire support member 45B is deflected to a maximum bend. At the same time, the wire support element 45B can be bent anywhere, more than just at its center point, so that the seated user receives a particularly comfortable and ergonomic support.

Seat 22B also includes a cushioning assembly 375 (fig. 40) comprising a cushion and upholstery or cover cloth. Supports 45B are contemplated to be so flexible and comfortable that the cushion can be removed. Alternatively, a cushion assembly 375 can be used, preferably having a thickness between% inch and 1 inch. The upholstery cover can be of any material, but should preferably allow some (but not too many) elastic stretches and yield for the shape changes allowed by the individual movement of the support members 45B to occur.

When the 375 cushioning assembly is sufficiently elastic and strong, the 375 cushioning assembly may include front and rear hook-shaped formations that allow it to hook onto a front and a rear of the seat support structure (i.e. frame 30B). (See explanation in Figs. 70-71 below).

It is contemplated that, in lieu of the support elements 45B comprising a single long wire with bent ends, that the support elements 45B can be made to include long elastic wires or rigid elements, supported at their ends by means of hinges on the side frame components, with the axis of rotation of the hinges extending forward and being at or slightly below the long spring wires. For example, fig. 52A discloses a seat having a modified lower frame component 359 made to include a strap 380 supported by a downwardly deflected elastic joint 381 at a bottom portion of where the second (inner) abutment surface 373 would be. The strap 380 is shaped grooved to receive a length of straight wire 382. When no user is seated, wire 382 extends horizontally, and elastic joint 381 moves to allow inner wall 367 'to move to a normal raised position. When a person sits in the seat, the elastic joint 381 flexes, causing the wall 367 'to tilt in and down. (See dashed lines.) This results in an action and movement similar to those indicated above with respect to seat 22B.

The upper seat frame component 358 (fig. 50) includes a perimeter frame portion with side sections 385 and 386, the rear section 387, and the "knee" 388 below-the-knee front section defining a large opening 389 to through which the support elements 45B extend. The side sections 385 and 386 are screw-coupled to the lower side frame components 359 and 360, and both harden the side frame components 359 and 360 and also capture the end sections 52b in the cavities 50B. The rear section 387 forms a rigid rear area of the seat 22B. The front section 388 extends forward 3 to 6 inches, and forms a front "waterfall" front surface that comfortably supports the thigh area of seated users of chair 20B. Multiple reinforcing grooves 390 and / or ribs provide optimum stiffness so that front section 388 flexes elastically but provides adequate support and good feel in both upright and reclined positions of the 20B chair. Front - rear leaf springs and transverse leaf springs can be added to optimize any of sections 385-388. In particular, it is contemplated that front / rear springs will be added to help maintain the transition area at the ends of the front section 388 close to a front of the side sections 385-386.

The illustrated 490 reinforced plastic springs (fig. 63) are made of flat extruded sheet springs to flex without taking a permanent deformation. They fit snugly into a recess in the upper frame component 358, and are held there against the lower frame components 359. It is contemplated that they will have a horizontal flat cross-sectional shape, and will extend toward the front end of the side sections 359, but other configurations and arrangements are possible, while still serving the same function.

The structure of the backrest 23B (Figs. 53-54) is not different from the structure of the seat 22B. Therefore, a detailed repetitive description is not necessary. However, it is noted that the back 23B includes a rear perimeter frame 70B with vertical side sections 400, 401, an upper cross section 402 and a lower cross section 403 defining a large open area 404. A lower part of the side sections 400 and 401 extend forward to form forward-extending side leg sections 135B, and are pivotally connected to the seat side sections at pivot 75B. The vertical side sections 400 and 401 include a bottom wall 405 (fig. 53), end walls 406 and 407, and inner and outer walls 408 and 410. The medium depth grooves 411 (fig. 54) are formed in the inner wall 408, and parallel walls 412 and 413 extend between inner and outer walls 408 and 410 on either side of each slot 411. There is a cavity 77B formed in the bottom wall 405 between the parallel walls 409-410. The protrusions 409 'are formed between the inner and outer walls 408 and 410, and are supported by a short intermediate wall 409 that extends between the adjacent parallel walls 412 and 413 (in places that do not affect voids or cavities 77B). Support elements 78B (similar to support elements 50B in seat 22B) are positioned in backrest 23B, and each includes a long section of wire 414 extending into grooves 411, and end sections curved into shape. of L 415 extending downward into cavities 77B. The movement of end sections 415 within cavities 77B is similar to that described above with respect to seat 22B. In the rest position, the end sections 415 abut the outer surfaces 417 of the cavities 77B, thus holding the wires in a partially bent state. When a seated user rests on the chair and is supported on the backrest, the long wire sections 414 flex, until the end sections 415 move to abut the inner stop surface 418, which limits any further flexing of the wire support elements 78B. The front covers 420 and 421 (fig. 53) are attached to vertical rear side sections 400 and 401. The covers 420 and 421 stiffen the side sections 400 and 401, and also support the end sections 415 within cavities 77B.

A cushioning assembly 375 '(fig. 40) similar to that described above with respect to seat 22B is attached to rear frame 70B. It can be fixed in different ways. It is contemplated that an optimal procedure is to stretch and hook the damping assembly to the upper and lower transverse frame sections 402 and 403. It is contemplated that a person skilled in the art will be able to use and adapt the coupling structure shown in FIGS. . 70-71 to the upper and lower parts of the backrest 23B to engage the rear cushion assembly 375 ', and to the front and rear parts of the seat 22B to engage the cushion assembly of the seat 375. Therefore, no description is necessary. detailed of each of them.

As shown in fig. 71, the lower frame section 403 of the rear frame 400 includes a pair of flanges 528 and 529 defining a rectangularly downward facing cavity or channel 530 that continuously extends through a width of the rear frame 400. A retention channel 531 (or flange if desired) channel 530 is formed in parallel along an outer front surface of the lower frame section 403. The cushioning assembly 375 'includes a shaped extruded plastic retaining clip. U 532, which includes a flat leg 533, a barbed leg 534, and an elastic section 535 connecting the legs 533 and 534. The legs 533 and 534 are spaced apart to receive and engage contacting the front flange 529. A protrusion retainer 536 is deflected in engagement with retainer channel 531 by elastic section 535.

The cushioning assembly 375 'further includes a sheet of upholstery material 540 connected to the flat leg 533 by a strip of elastic sheet material 541. (Alternatively, the elastic sheet material 541 can be removed, and the upholstery material 540 engage directly with the flat leg 533, if the test shows that the added elastic stretch of the sheet material 541 is not required). Specifically, one of the edges of elastic sheet material 541 is sewn to flat leg 533 of clip 532 by seam 542, and an opposite edge is sewn to upholstery material 540 by seam 543. Strip 541 fully extends to across a width of the rear frame 400. Different methods are known for attaching and sewing upholstery material 540 to strip 541, and for attaching and sewing strip 541 to flat leg 533, so that only a single seam is illustrated. simple. It is contemplated that in a preferred form, in addition to sheet material 541, a foam layer 544 and stable backing sheet 545 are attached to cushion assembly 375 ', although this is not necessary.

To attach the cushion assembly 375 'to the rear frame 400, the flat leg 533 of the extruded clip 532 of the cushion assembly 375' is pressed into the channel 530 of the lower frame section 403 of the rear frame 400, with the opposite leg 534 frictionally coupling to an outer front surface of the lower frame section 403. The combined thickness of the elastic sheet material 541 and the flat leg 533 captured within the channel 530, together with the retention projection 535 engaging the retention channel 531, form a strong secure connection that retains and maintains the damping assembly 375 'to the rear frame 400. The blades 540 and 541 are observed to overlap on the barbed leg 534 when the damping assembly 375' is fully installed in the rear frame 400 (see arrow 548 in fig. 71, and see the assembly in fig. 70). Since the barbed leg 534 has a thickened cross section, a tension in the blades 540 and 541 further deflects the retaining boss 535 toward engagement with the retaining channel 531. In addition, the thickened section of the barbed leg 534 may assist to hide the seam, providing a space to receive the sewing area and to receive the multiple thickness of folds in the sewing area.

A rail 424 (fig. 55) is formed at a front portion of an inwardly directed flange 425 in the side sections 400 and 401. The rail 424 extends vertically from about one-half to two-thirds the length of the side sections 400 and 401, and includes a top or end termination 426 that forms an access port to engage rail 424. Different accessories can be mounted on rail 424. For example, a lumbar device 427 and a headrest bracket 428 are illustrated (fig. 40).

The illustrated lumbar device 427 (Fig. 55) includes a plastic body 430 that extends around flange 425, a pair of hook-shaped retention fingers 431 that slidably engage rail 424, and a handle 432 that extends from the body 430 in front of the retainer 431. A pair of retaining protrusions or ridges 433 are formed in the body 430 adjacent to the retaining fingers 431, and are adapted to engage in form of retention with successive wire support elements 78B as lumbar device 427 moves up and down. Interestingly, lumbar device 427 can be adjusted downward to an unused storage position (see Fig. 59), where lumbar device 427 is so low that it is effectively deactivated since it is no longer effective in providing lumbar support for a seated user. As the lumbar device 427 moves upward, the area of the body 430 adjacent to the retaining protrusions 433 supports the length wire sections 414 at the interior locations of the interior wall 408. (See FIG. 56). Therefore, the effective flexible length of the long wire sections 414 is reduced, as illustrated in FIGS.

56-57. Therefore, the added lumbar support comes from less flexing of the long wire sections 414, and does not come from a forced change of shape in the lumbar support area in the backrest 23B (although it could also be designed to create a change in shape in the lower back, if desired). This "flat" fit is believed to have good ergonomic benefits as a seated user receives the added lumbar support they desire, however their back and upper torso are not forced to assume a different body shape.

Another important discovery is the independent action of the right and left lumbar devices 427. By adjusting the lumbar and right devices 427 to the same height, a maximum lumbar support force can be achieved in a particular area (ie they are supported long two-wire support sections 414). By adjusting the left and right lumbar devices 427 to different heights, the lumbar support area is effectively enlarged (i.e., long four wire support sections 414 are supported). Furthermore, when one lumbar device 427 is set high and the other is set relatively low, but still in an effective lumbar support area, the 427 lumbar devices provide an exceptionally wide range of non-uniform adjustment, i.e. further to the right in one zone and more to the left in another zone. It is also conceived that different lumbar devices 427 are available, so that a user can select the desired lumbar support by choosing an appropriate lumbar device 427.

Even if only one of the illustrated lumbar devices 427 is used (for example, if the other lateral lumbar support device 427 is parked in the off position), the seated user does not feel unbalanced lumbar support from the backrest 23B. However, it is conceived that the present lumbar device 427 may be designed to appreciably shift the lumbar support to one side (i.e., the long wire section 414 is supported only on one side, so that more lumbar support is available at one side of the chair and less support on the other side). This principle may seem undesirable since the lumbar support is unbalanced. However, tests have shown that some seated users want and even prefer unbalanced lumbar support. This may be especially true for users who have a curved spine, where uneven support has beneficial health effects. Additionally, users may desire different lumbar support at different times, by sitting and / or reclining sideways in asymmetrical positions, and as they rotate and move to different unbalanced positions in their chairs.

The illustrated rear frame 70B (fig. 67) has a unique construction that makes mounting easy. The bottom 500 of side sections 400 and 401 is hollow and each defines an arcuate cavity 501. The side sections of leg 135B include an arcuate shaped body 502 configured to slide telescopically into cavity 501. Once Telescopically together, holes 503 and 504 in bottoms 500 and side leg sections 135B are aligned. The pivot pins extend through holes 503 and 504 to form a pivot 75B, and both secure the components (bottoms 500 and side leg sections 503 and 504) together, but also act as pivots for the rear frame 70B in seat 22B.

The side frame elements 322 of the seat 22B include a pair of arcuate recesses 510 (Figs. 48 and 67) that partially extend circumferentially around the hole 75B. The recesses 510 and holes 75B form a bow tie feature. An inner side of the side leg sections 135B includes a pair of opposite protrusions 511 (FIG. 67) that fit into recesses 510. The protrusions 511 engage the opposite ends of the cavity 510 when the rear frame 70B (ie, backrest 23B) is rotated around pivot pins 505 between the vertical and fully reclined positions, thus acting as a stop to adjust a maximum recline position of backrest 23B.

A 440 headrest (fig. 60) can be added to chair 20B. Headrest 440 includes headrest bracket 441 and a set of vertically and angularly adjustable headrests 442. Headrest bracket 441 includes a center tube 443 and right and left arms 444 and 445 that extend to the side sections 400 and 401 of the frame posterior 70B. Center tube 443 is positioned toward the rear of the upper frame cross section 402 and includes a flange 443 'configured to securely engage and be affixed to the upper frame section 402 of the rear frame 70B. Alternatively, it is contemplated that tube 443 may be positioned below and in line with an opening in the rear flared upper frame member 402 of backrest 238. Arms 444 and 445 each have an end 447 configured to engage accessory rail 424. for stability. Headrest assembly 442 includes a padded C-shaped head coupling bracket 441. A pair of brackets 449 are attached to a rigid sheet backing 448 below the C-441-shaped bracket. A riser 450 includes a riser 451 that slidably extends through the opening in center tube 443. Retains in riser 450 and tube 443 may be provided to retain the headrest in a selected position.

An upper part of the vertical support 450 includes a transverse T-shaped part 452 (fig. 61) that extends between the supports 449. The part 452 (fig. 61) includes a hollow tube element 453 with longitudinal grooves 454 around its inner surface. A bar 455 extends between and is coupled to supports 449. Bar 455 includes a pair of longitudinal channels 456, and a pair of retaining rods 457 are located in channels 456. Springs 458 are located in transverse holes in the bar 455, and deflect the retaining rods 457 outwardly into engagement with the notches 454. By this arrangement, the headrest assembly 442 can be angularly adjusted over the headrest support 441. The headrest support structure in the form of C 448 has a front surface that, in cross section, is spiral in shape and is not symmetrical around bar 455. Due to the shape of the C 448 headrest support structure, the effective area to support the head of a seated user moves forward as the headrest support structure 448 adjusts rotatably angularly.

Seat supports (fig. 50), backrest supports 78B (fig. 53), seat frame 30B (figs. 45 and 50), rear frame 70B (figs. 53 and 69), springs 123B ' and 137B and control mechanism 24 (fig. 45) form a compatible chair assembly that results in a soft stop when the backrest 23B reaches an upright position, and results in a soft stop when the backrest 23B reaches a position fully reclined. Avoiding a hard "snap" or choppy stop, combined with the fluidity and smoothness of running during recline is remarkable, and results in a surprising and unexpected level of support and comfort for a seated user.

It has been found that during recline of chair 20B (fig. 40) (and similarly chair 20 of fig. 1), the structure of the joint 132B and the arms 127B and the rear frame in the upright 123B position allow some compatible movement of the backrest 23B even when the backrest stop member 205B is applied. Specifically, with the illustrated components, when the backrest 23B "bottoms" against the backrest stop during recline, the support arms 127B and related components in the present chair control provide internal compatibility for the previously unseen control at previous chair controls. Specifically, the 127B arms and related components allow the 23B backrest to provide and meet a limited but noticeable quantity. Therefore, at the point of engagement of the backrest stop, an increase in the support force of the backrest is available for the seated user ... but the sensation of a rigid "brick wall" stop is avoided. Instead, the compatible support arms 127b and the upright rear frame 123B flex, allowing the backrest 23B to move along a limited changed path to provide a compatible "soft stop". The forces in the backrest 23B along this limited changed path can be controlled by varying a resistance and the strength of the various structural elements of the chair, as will be understood by a person skilled in the art of chair and unit manufacturing seat.

Although an office chair is illustrated, it is specifically contemplated that the present inventive concepts are useful in seating units other than office chairs.

It should be understood that variations and modifications can be made in the aforementioned structure without departing from the concepts of the present invention, as defined in the following claims.

Claims (24)

1. A seat unit having a base (21; 21B), a seat (22), a backrest (23; 23B) and a control (24) arranged to operatively engage and support the backrest for movement between the vertical and reclined positions, the control including a housing, a first mechanism (123 ', 137, 123B', 137B) arranged to provide a deflection support force to the backrest during recline, an energy adjustment mechanism (150 ) and a backrest stop mechanism (203), characterized in that: the control includes an actuator (155, 156, 205) movable to a first operating position to selectively engage the power adjusting mechanism, and movable to a second operating position to selectively engage the backrest stop mechanism, the adjusting mechanism comprising (150) a booster mechanism (25) capable of increasing the supporting force, the actuator (155) comprising an on / off selector device (155) to selectively activate and deactivate the booster mechanism. 2. A seat unit according to claim 1, wherein the actuator (155), when in the second operating position, engages the power adjustment mechanism (150) and the backrest stop mechanism (203). 3. A seat unit according to claim 1, wherein the actuator (155) is movable to a deactivated position where the actuator is disengaged from the power adjustment mechanism (150) and the backrest stop mechanism (203). A seat unit according to claim 1, wherein the actuator (155) is operably pivotally mounted to the housing. 5. A seat unit according to claim 4, wherein the on / off selector device (155) is mobile with little effort which is separate and independent of any friction generated by the spring components (151, 152, 153 ) of the reinforcing mechanism (25). 6. A seat unit according to claim 5, wherein the reinforcing mechanism (25) includes an elastic spring (150), and the on / off selector device (155) comprises a stop surface (156) engageable with the pier. 7. A seat unit according to claim 6, wherein the spring comprises a torsion spring (150). 8. A seat unit according to claim 1, wherein the actuator (155) includes a backrest stop (205), and wherein the backrest stop can be actuated to selectively engage the backrest stop mechanism (203) which limits the recline of the backrest (23, 23B). 9. A seat unit according to claim 8, wherein the backrest stop (205) includes a first first step stop surface (206) that limits the backrest to partial recline. 10. A seat unit according to claim 9, wherein the backrest stop (205) includes a second second step stop surface (207) that limits the backrest to zero recline. 11. The seat unit according to claim 1, wherein the on / off selector device includes a manually operated hand control (227; 300). 12. The seat unit according to claim 11, wherein the manual control includes a single control (227, 300). 13. A seat unit according to claim 12, wherein the manual control includes a detent knob (300). 14. A seat unit according to claim 12, wherein the manual control includes a handle (236) and a clutch (233) operatively supported within the handle. 15. A seat unit according to claim 1, wherein the backrest stop mechanism (203) includes a link (132; 132B) operatively coupled to the seat base (21; 21B) and one (22; 22B) of the seat and the backing. 16. A seat unit according to claim 15, including a backrest stop (205; 205B) movable between an uncoupled position allowing full backrest recline and an engaged position that limits backrest recline, and wherein the Joint includes an arm (132; 132B) that engages the backrest stop when the backrest stop is activated. 17. A seat unit according to claim 1, wherein the first mechanism includes compatible arms (123 ', 137; 123B', 137B) extending from the base and supporting at least one of the seat (22; 22B) and the backrest (23; 23B) for movement during recline. 18. A seat unit according to claim 1, including a pivot pin (133; 133B) keyed to, and supporting, the link (132; 132B); and wherein the reinforcing mechanism (25) includes a torsion spring (150) keyed to the pivot pin, the torsion spring having a projection (154; 154B), and wherein the on / off selector device ( 155; 155B) engages the projection to activate the torsion spring. 19. A seat unit according to claim 1, wherein the control includes a powered mechanism (300; 301; 302) for powered engagement and disengagement of the booster mechanism (25). 20. The seat unit according to claim 19, wherein the powered mechanism includes an electromechanical device (300; 301; 302) adapted to engage and disengage the booster mechanism. 21. A seat unit according to claim 17, wherein the compatible arms (123 '; 137; 123B'; 137B) are strong and absorb energy during recline. 22. A seat unit according to claim 1, wherein the base includes wheels to engage a floor surface. 23. A seat unit according to claim 18, wherein the torsion spring has an inner ring (151) keyed to the pivot pin, a second outer ring (153) having a protrusion extending from the second outer ring , and an elastic spring portion (152) operatively interconnecting the inner and outer rings. 24. A seating unit according to any one of the preceding claims, wherein the actuator comprises a single actuator.