JP2024035223A - Chair - Google Patents

Abstract

The present invention aims to downsize and increase the number of adjustment stages in an elasticity adjustment device that changes the resistance to backward tilting of a backrest in stages by changing the contact position of an operating unit with respect to a rotary load receiving arm. A spring unit 54 moves up and down using its front end as a fulcrum. The cam 56 that adjusts the rotation angle of the spring unit 54 is of a horizontal rotation type, and the rotation of the cam 56 is converted into rotation of the spring unit 54 via a forward-backward movement type interlocking member 59 and a slider 57. . Since the cam 56 is horizontally rotatable, the space in which the cam 56 is disposed can be reduced to make the support mechanism portion more compact. Even if the spring unit 54 tends to rotate upward, no external force is applied to the cam 56, so fine elasticity adjustment can be performed by increasing the number of stages of the cam surfaces 71 to 79. [Selection diagram] Figure 8

Description

The present invention relates to a reclining chair in which a backrest tilts backward against spring means, and more particularly to a reclining chair in which the amount of resistance of the spring means to the backward tilting of the backrest can be adjusted.

Reclining chairs have spring means that provide resistance to the backward tilting of the backrest, but in general, the magnitude of the resistance of the spring means to the backward tilting of the backrest (i.e., the magnitude of the reaction force of the backrest that acts on the body when reclining) An elasticity adjustment means is provided to change the elasticity. Compression coil springs are often used as the spring means. On the other hand, there are two types of elastic adjustment devices: a stepless type using a rotary screw, and a stepless type using a cam or lever.

Mechanisms for changing the magnitude of the resistance of the spring means are broadly classified into two types: a method that changes the amount of initial pressure applied to the spring means, and a method that changes the moment acting on the spring means. As the latter method, the applicant of the present invention disclosed in Patent Document 1 a method in which the inclination angle of a rotary spring unit is changed using a cam.

In Patent Document 1, the center of rotation of the spring unit is located at the front end, and the spring unit is in a horizontally longitudinal posture. Therefore, the load due to the tilting of the backrest acts on the spring unit from behind via the load support arm. On the other hand, the cam is a circumferential cam, and is arranged above the rear part of the spring unit so as to rotate around the left and right longitudinal axes, and when the cam is rotated by operating a lever, the side view posture of the spring unit changes. As a result, the resistance to backward tilting of the backrest changes.

Patent No. 5869791

Now, a typical elasticity adjustment means for a chair is one in which one end of a compression coil spring is received by a rotary hand, and the initial compression force of the coil spring is adjusted by rotating the handle. Since the repulsive force of the coil spring acts directly on the handle, there is a problem that a large amount of resistance is applied to the rotation operation of the handle, and another problem is that due to the large resistance, the handle must be rotated many times, which takes time and effort to adjust. There is.

On the other hand, in Patent Document 1, the backrest load due to backward tilting of the backrest acts as a force that compresses the spring unit, but since the acting direction of the backrest load and the direction of contact of the cam with the spring unit are different, the backrest load is It does not act directly on the cam. Therefore, the elasticity can be easily adjusted by rotating the cam with a light force.

Although Patent Document 1 has such advantages, upon study by the inventors of the present application, it was found that there is room for improvement. For example, it can be said that there is room to increase the number of cam stages and realize fine elasticity adjustment. There is also room for consideration of reducing the bulk of the elasticity adjusting device to make it more compact.

The present invention has been made in view of the current situation, and aims to disclose an improved technique based on the elasticity adjustment mechanism of the previous application.

The present invention is
A base provided at the upper end of the leg device, a spring unit disposed on the base to elastically support the backward tilting movement of the backrest, and a pushing member that applies a load due to the backward tilting movement of the backrest to the spring unit. have,
The spring unit and the pushing member rotate about the left and right longitudinal axes, and by rotating the spring unit using an elasticity adjustment device and changing the abutment position with respect to the pushing member in the vertical direction. , changing the resistance to backward tilting of the backrest.
This is the basic configuration.

In the above basic configuration, the invention of claim 1 has the following features:
"The elasticity adjusting device includes a cam that rotates when a handle is operated, and an interlocking member that moves due to the rotation of the cam and rotates the spring unit. The direction of action of the force of the interlocking member is different from that of the interlocking member.
It has the following characteristics.

The present invention can be developed in various ways. As an example, in claim 2,
"The interlocking member is attached to the base so as to be movable back and forth, and the side view posture of the spring unit is changed by the back and forth movement of the interlocking member,"
The cam is a circumferential cam, and is disposed behind the interlocking member and is horizontally rotatably attached to the base.
The structure is as follows.

The invention of claim 3 is a development example of claim 2,
"A swinging head is connected to the front end of the interlocking member via a left and right longitudinal axis, and the head is attached to the top surface of the spring unit so as to be slidable back and forth."
The structure is as follows.

The invention of claim 4 is a development example of any one of claims 1 to 3,
"The cam is provided with a wheel on which a wire is locked or wound, and the rotation of the handle is transmitted to the rotation of the cam via the wire."
The structure is as follows.

In claim 4, two wires, a forward rotation wire and a reverse rotation wire, may be used, or one wire may be used. If you use two wires, you can hook one end of both wires to the cam wheel so that when one wire is pulled by the handle, the other wire is pulled by the cam. If you are using a single wire, you can hook both ends of the wire to the handle and wrap the middle part of the wire around the cam wheel.

The invention of claim 5 is a development example of claim 4,
"The wire is connected to a rotor that is concentric with the handle, and a clutch is interposed between the handle and the rotor that causes the handle to idle when the cam is fully rotated in either direction."
The structure is as follows.

Moreover, the invention of claim 6 is, in claim 2 or 3,
"The interlocking member and the cam are provided with an engaging portion that allows them to move relative to each other while holding them so that they cannot be separated back and forth."
The structure is as follows.

Similar to Patent Document 1, the present invention adjusts the reclining elasticity by changing the moment acting on the spring unit, and does not change the initial load applied to the spring unit, so It is possible to prevent or significantly suppress the elastic restoring force of the spring means from acting as resistance. Therefore, even if the operating member is compact, the cam can be easily rotated. In other words, the elasticity of the reclining spring means can be easily adjusted with one touch using a compact operating member.

Since the spring unit is urged to return to its standard position and rotate, if the outer peripheral surface (cam surface) of the cam is in direct contact with the spring unit, it is necessary to stably hold the cam. However, a part of the perpendicular line of the cam surface must be orthogonal to the rotational axis of the cam, which makes it difficult to increase the number of cam surfaces.

On the other hand, when the interlocking member is arranged between the spring unit and the cam as in the present invention, the reaction force that returns the spring unit to its origin does not act as a force that rotates the cam, so that a portion of the perpendicular line of each cam surface does not necessarily have to intersect with the center of rotation of the cam. Therefore, by increasing the number of cam stages, fine elasticity adjustment becomes possible.

Further, since the cam and the rotation axis do not need to be parallel to the rotation axis of the spring unit, the cam can be arranged more freely and the adjustment mechanism can be prevented from becoming bulky. By increasing the freedom of cam placement, the outer diameter of the cam can be increased, which also has the advantage of allowing the number of cam stages to be increased without difficulty.

Although the interlocking member may be rotatable (or rotatable), if the interlocking member is configured to be reciprocating as in claim 2, the force transmission mechanism can be simplified. Additionally, since the cam is horizontally rotatable, it can be easily placed in spaces with narrow vertical spacing. Therefore, the elasticity adjustment mechanism can be made more compact and less bulky.

When the interlocking member is a reciprocating type as in claim 2, when combined with a swinging head as in claim 3, the interlocking member can be moved horizontally and the spring unit can be rotated, so the cam The movement can be made more accurate by simplifying the interlocking relationship between the interlocking member and the interlocking member.

A rigid member such as a rod can also be used as a means of transmitting the movement of the handle (operating tool) to the rotation of the cam, but in this case, multiple rigid members are required, and the rigid members are connected with each other with pins while other members are connected. It is very difficult to design and difficult to assemble because the rigid members must be arranged so that they do not interfere with other members. When the power transmission method using a wire is adopted as in claim 4, the arrangement position and posture of the handle are not restricted, so that design freedom can be greatly improved and assembly effort can be reduced.

The cam has multiple cam surfaces with different heights, and the cam surface with the lowest height and the cam surface with the highest height are adjacent to each other, but the load acting part of the spring unit is located on the load supporting arm. Because it moves in the longitudinal direction, the spring unit cannot directly transition from the posture with the smallest rotation angle to the posture with the largest rotation angle, nor can it directly transition from the posture with the largest rotation angle to the posture with the smallest rotation angle. .

Therefore, if the rotation in the direction in which the height of the cam surface increases is defined as normal rotation, and the rotation in the direction in which the height of the cam surface decreases is defined as reverse rotation, then normal rotation starts from the state where the height of the cam surface is the highest. The height of the cam surface cannot be reversed from the lowest position.

In this case, if an excessive tensile force is applied to the wire with the cam fully rotated in either direction, the wire may break or the member to which the wire is connected may be damaged or deformed. On the other hand, if the configuration of claim 5 is adopted, if a certain amount of pulling force is applied when the cam is fully rotated, it is possible to prevent the handle from rotating idly with respect to the rotor, thereby preventing excessive pulling force from acting on the wire. . Therefore, breakage of the wire and damage/deformation of the members can be prevented.

Now, in a circumferential cam, the distance from the rotation axis to the outer circumferential surface changes stepwise or steplessly, and if the distance from the cam axis to the interlocking member increases, the interlocking member Since the cam is forcibly pushed, the interlocking relationship between the cam and the interlocking member is ensured. However, if the distance from the cam axis to the interlocking member decreases, and there is friction on the interlocking member, the cam There is a risk that the interlocking member will not move even if it rotates. Regarding this point, it is possible to use a spring to bias the interlocking member toward the cam, but using a spring increases the rotational resistance of the cam, requiring a large force for operation, and the frictional resistance of the interlocking member increases. If it is large, there is a concern that the interlocking member will not move even if it is biased by a spring.

In this regard, when the structure of claim 6 of the present application is adopted, since the interlocking relationship between the cam and the interlocking member is always maintained, elastic adjustment for reclining can be performed without increasing the operating force of the cam.

It is a figure showing the appearance of the chair concerning an embodiment, (A) is a front perspective view, (B) is a front view, and (C) is a rear perspective view. (A) is a perspective view of the chair seen from the lower rear, and (B) is a right side view. FIG. 3 is a perspective view with the seat section separated. FIG. 3 is an exploded perspective view of the seat. (A) is an exploded perspective view showing the reclining mechanism, (B) is an exploded side view showing the reclining mechanism, and (C) is a bottom view of the cam unit. (A) is a perspective view showing the mounting structure of the second tilting frame, and (B) is a downward perspective view showing the arrangement relationship between the first tilting frame and the second tilting frame. It is a figure which shows the attachment structure of the gas cylinder for tilt control, (A) is an exploded perspective view seen from the rear upper part, and (B) is an exploded perspective view seen from the rear lower part. (A) is an exploded perspective view showing the elasticity adjusting device, (B) is a rear view of the spring unit and the cam unit, and (C) is a downward perspective view of the spring unit and the cam unit. Both (A) and (B) are perspective views showing a cam operating mechanism section. (A) and (B) are lower perspective views showing the operating mechanism of the cam, (C) is a side view of the operating unit, and (D) is a perspective view of the operating unit. (A) is a perspective view showing the arrangement of the operation unit, (B) is an exploded perspective view of the operation unit, and (C) is a plan view of the main parts. It is a figure which shows a modification, (A) is a side view of an important part, (B) is an isolated perspective view of an important part.

Next, embodiments of the present invention will be described based on the drawings. In the following, words such as front and back and left and right will be used to specify the direction, but this direction is defined as the direction seen from a person sitting normally on a chair. The front view is a view seen from the direction facing the seated person.

(1).Overall overview First, an overview of the chair will be explained. This embodiment is applied to a rotary chair for office use. The chair includes a leg device 1, a seat 2, and a backrest 3 as basic elements. The leg device 1 has a structure in which a leg support 4 made of a gas cylinder is erected at the center of a base having five leg blades, and a caster is provided at the tip of each leg blade.

As shown in FIG. 2, a base 5 is fixed to the upper end of the leg support 4, and the lower tips of the left and right first tilting frames 6 are connected to the base 5. As shown in FIG. 2(A), the first tilting frame 6 extends rearward from the base 5 and stands up while spreading outward to the left and right, and the upper part of the first tilting frame 6 is connected to the lower back frame 7. Continuing with side member 8. The lower end of the lower back frame 7 is composed of left and right longitudinal lower members 9.

As can be understood from FIG. 2, the lower end of the upper back frame 10 is connected to the upper end of the lower back frame 7. The upper back frame 10 has a loop structure including left and right side members 11, an upper member 12 connected to the upper ends thereof, and a lower member 13 connected to the lower ends of the left and right side members 11.

The lower ends of the left and right side members 11 of the upper back frame 10 are connected to the upper ends of the side members 8 of the lower back frame 7 so as to be tiltable backward. On the other hand, the lower member 13 of the upper back frame 10 projects backward, and the upper end of the second tilting frame 14 is connected to the backwardly projecting lower member 13 so as to be tiltable backward. The lower end of the second tilting frame 14 is connected to the rear part of the base 5.

The backrest 3 also includes a backboard 15 made of a flexible resin material such as elastomer, and upholstery (not shown) stretched over the front surface of the backboard 15. Since the back plate 15 is made of a flexible resin material, it has excellent fit to the body of a seated person. Further, when reclining, the upper back frame 10 and the lower back frame 7 rotate relative to each other, and the elastic deformation of the back plate 15 allows the relative rotation of both frames 10 and 7.

An upper rest 16 that supports the head and neck of the seated person is attached to the upper end of the backrest 3 so that its height can be adjusted. The tilting frames 6 and 14 and the upper back frame 10 can be die-cast products of light metal such as aluminum, or molded products of engineering plastic.

(2).Outline of the seat part/first tilting frame As shown in Fig. 3, the seat 2 includes a seat inner shell (seat plate) 20 made of resin and a cushioning material 21 overlapping the upper surface of the seat inner shell (seat plate) 20. The cushion material 21 is covered with upholstery. The seat 2 is fixed to a resin seat support plate (seat outer shell) 23 placed below it, and the seat support plate 23 is movable back and forth but cannot be detached from an intermediate member 24 placed below it. is supported by

The intermediate member 24 includes a front and rear longitudinal side frame portion (bank portion) 24a that constitutes a back side portion thereof, and a handle (knob) for moving the seat 2 back and forth in the front portion of the side frame portion 24a. I am wearing 25. Note that the seat 2 can be adjusted by moving back and forth while the person is still seated on the seat.

As shown in FIGS. 3 and 4, a front member 26 having left and right longitudinal sides close to the left and right width of the seat 2 is connected to the front end of the base 5 so as to rotate about the left and right longitudinal axis. Angular front protrusions 27 are provided on both left and right ends of the frame to protrude upward, while, as shown in FIG. A facing projecting portion 6a is provided, and an upward rear protrusion 28 is formed at the tip of the outward projecting portion 6a.

The side frame portions 24a of the intermediate member 24 are connected to these front and rear projections 27, 28 by left and right longitudinal pins 29 (see FIG. 4). Therefore, when the first tilting frame 6 tilts backward, the seat 2 tilts backward while retreating, but the degree of backward tilting is smaller than that of the first tilting frame 6. As shown in FIG. 5(A), a lower cover 30 is attached to the lower surface of the base 5.

As shown in FIG. 3, the intermediate member 24 is formed with a large relief hole 31 that opens upward and downward. Further, the seat support plate 23 is also formed with an escape hole 31 that opens upward and downward. Note that behind the handle 25 for moving the seat 2 back and forth, a lift lever 32 for adjusting the height of the seat 2 is arranged.

(3).Second tilting frame/tilting control device As clearly shown in Fig. 6, the lower part of the second tilting frame 14 is formed into a bifurcated shape, and a left and right longitudinal second support shaft 35 is fixed to the tip of the second tilting frame 14. ing. The second support shaft 35 is supported by upper and lower bearings 36 and 37 that are divided into two parts, and the upper and lower bearings 36 and 37 are fitted from above into upward opening grooves 38 formed at the rear of the base 5. The cover plate 39 is fixed to the base 5 with screws and is held in such a way that it cannot be separated. Therefore, the second tilting frame 14 rotates (tilts) using the second support shaft 35 as a fulcrum.

Tilt control of the backrest 3 is performed by a tilt control gas cylinder 40 shown in FIGS. 6 and 7. That is, the tilt control gas cylinder 40 switches between a state in which the backrest 3 freely reclines and a state in which it is held in an arbitrary posture.

As clearly shown in FIG. 7(B), a bracket 41 having left and right side plates is fixed to the tip of the piston rod constituting the tilting control gas cylinder 40, while a bracket 41 having left and right side plates is fixed to the left and right intermediate portions of the rear end of the base 5. A bearing rib 42 sandwiched between the bracket 41 of the tilting control gas cylinder 40 is integrally formed in the bearing rib 42, and the bearing rib 42 and the bracket 41 are connected by left and right longitudinal support shafts 43. On the other hand, the upper rear end of the tilting control gas cylinder 40 is connected to a bearing boss 44 provided at the bifurcated base of the second tilting frame 14 by left and right longitudinal pins 45.

A case 46 is attached to the lower end of the tilt control gas cylinder 40, and a lever member (not shown) for pushing and operating the bush valve of the tilt control gas cylinder 40 is attached to the case 46. The lever member is rotated by pulling a tilting operation wire inserted into the tube. The pulling operation of the tilting operation wire is performed by a tilting control lever 47 shown in FIG. The tilt control lever 47 is attached to the right side frame portion 24a of the intermediate member 24 behind the elastic adjustment handle 48.

(4). Resilience Adjustment Mechanism As shown in FIG. 5, a square (hexagonal) first support shaft 50 is mounted between the front ends of the first tilting frame 6. The first support shaft 50 is held so as not to rotate relative to the first tilting frame 6, and is rotatably held in a bearing hole 51 provided in the side plate 5a of the base 5 via a bush 52. Further, a downwardly extending load receiving arm 53 is attached to the left and right intermediate portions of the first support shaft 50 so as to be relatively non-rotatable. The load receiving arm 53 is tilted backward (gently curved) in a side view so as to shift forward as it goes downward.

The load receiving arm 53 is arranged inside the base 5, and a spring unit 54 is arranged inside the base 5. The spring unit 54 includes a spring case 54a that opens rearward, a movable spring receiver 54b that is arranged inside the spring case 54a so as to be movable back and forth and whose rear end is exposed backward, and a movable spring receiver 54b that is arranged inside the spring case 54a. The movable spring receiver 54b has a spring (not shown) that urges the movable spring receiver 54b backward, and the rear end of the movable spring receiver 54b is in contact with the front surface of the load receiving arm 53. The movable spring receiver 54b is held in a manner that cannot be removed from the spring case 54a.

The front end of the spring case 54a is connected to the base 5 by left and right longitudinal support shafts 55 (see FIG. 5(B)), and the spring unit 54 rotates to bring the movable spring receiver 54b into contact with the load receiver arm 53. By changing the position in the vertical direction, the strength of resistance against backward tilting of the backrest 3 changes. That is, when the spring unit 54 rotates, the load support span of the load receiving arm 53 changes, and the strength of resistance against the backward tilting of the backrest 3 changes.

The angle adjustment of the spring unit 54 is performed by rotating a cam (peripheral cam) 56 shown in FIGS. 5(B) and 8(A) and 8(B). The cam 56 is horizontally rotatably mounted on the upper surface of the base 5 at a position behind the spring unit 54, while a slider 57 is mounted on the upper surface of the spring case 54a by a dovetail mechanism so as to be movable back and forth and upward. An interlocking member 59 is connected to the slider 57 by longitudinal connecting pins 58, and a cam 56 abuts the rear end of the interlocking member 59 from behind.

As shown in FIG. 5(A) and FIG. 8(A), a boss 60 for rotatably holding the cam 56 is formed on the upper surface of the base 5, and the cam 56 is attached to a screw 61 (see FIG. ) is held by the boss 60 so that it cannot be removed. As shown in FIG. 5(C) and FIG. 8(C), roller holding holes 62 are formed at three circumferentially separated locations on the lower surface of the cam 56. ) is inserted. Therefore, the cam 56 rotates without wobbling.

As shown in FIG. 8B, left and right dovetail grooves 63 are formed in the slider 57 so as to face each other, and the dovetail grooves 63 hold a flange 64 provided on the spring case 54a. Therefore, the slider 57 is held movably in the longitudinal direction (back and forth direction) of the spring case 54a.

As shown in FIGS. 5(A) and 8(A), the base 5 is formed with a cutout 65 into which the slider 57 can move freely back and forth, and the interlocking member 59 is located on the left and right outer sides of the cutout 65. It overlaps the base 5 from above and is held by an upper cover 66 shown in FIG. 9 so as not to be able to move upward. As shown in FIGS. 5(A) and 8(B) and FIG. 8(A), the slider 57 is urged in the backward direction by a spring 67. The spring 67 is supported from the front and rear by a front spring receiver 68 provided on the spring case 54a and a rear spring receiver 69 provided on the slider 57.

At the rear end of the interlocking member 59, a support protrusion 70 that protrudes from the outer peripheral surface of the cam 56 is provided to protrude backward. On the other hand, first to ninth cam surfaces 71 to 79 are formed on the outer peripheral surface of the cam 56. The cam surfaces 71 to 79 are recessed in the axial direction when viewed from above, and the distance (height) from the axial center increases from the first cam surface 71 to the ninth cam surface 79. It's changing.

When the cam surfaces 71 to 79 are formed into concave surfaces as in the embodiment, the posture of the cam 56 can be stabilized. When shifting to a lower cam surface, the support protrusion 70 is in a state of climbing over the peak of the cam 56, so the cam 56 will not rotate unless a certain amount of force is applied. On the other hand, since there is originally resistance to transition from a low cam surface to a high cam surface, the cam 56 will not rotate unless a certain amount of force is applied in this case as well. Therefore, the cam 56 is stably held in the set posture.

(5). Resilience Adjustment Operation Mechanism The rotation of the cam 56 is performed by the rotation of the elasticity adjustment handle 48, as described above. This point will be explained mainly with reference to FIGS. 9 to 11.

As shown in FIG. 9, an operating unit 80 including the elastic adjustment handle 48 is attached to the right bank portion 24a of the intermediate member 24. As shown in FIG. As shown in FIG. 11(B), the operation unit 80 includes a holder 82 fixed to the outer surface of the right bank portion 24a with screws 81. Inside the holder 82, from the back, a wheel 83, a collar 84, a spring (compression coil spring) 85, and a movable clutch 86 are arranged. The holder 82 is formed with a pocket 88 that opens upward and into which a nut 87 into which the screw 81 is screwed is inserted.

On the other hand, the elastic adjustment handle 48 has a central shaft 89, and a fixed clutch 90 is built into the elastic adjustment handle 48 while being fitted onto the central axis 89. The fixed clutch 90 and the movable clutch 86 can be engaged and disengaged, and therefore the teeth of both clutches 86 and 90 are trapezoidal (triangular may also be used). An engagement protrusion 91 is formed on the rear surface of the fixed clutch 90, and the engagement protrusion 91 is fitted into an engagement hole 92 provided in the elastic adjustment handle 48. Therefore, the fixed clutch 90 rotates together with the elastic adjustment handle 48.

The wheel 83 and the movable clutch 86 are keyed so that they can slide and rotate together. Further, the wheel 83 is rotatably connected to the central shaft 89 by a screw 93 in a non-removable manner. The holder 82 includes an intermediate wall 94, the wheel 83 is located on the inside with the intermediate wall 94 in between, and the movable latch 86 is located on the outside with the intermediate wall 94 in between.

Two annular grooves 95 are formed in the wheel 83, and a pair of ball holding portions 96 corresponding to the pair of annular grooves 95 are formed in a part of the outer periphery. Further, two upper and lower tube holding parts 97 are formed in the rear lower corner of the holder 82, and an end fitting 99 provided at the end of the tube through which the wire 98 is inserted is attached to the tube holding part 97. There is. The tube holding portion 97 has a semicircular groove shape and includes an inward flange, and the end fitting 99 has a cylindrical shape and has an annular groove formed therein. An end fitting 99 provided on the holder 82 is held by the side surface of the intermediate member 22 so as not to be detachable.

A ball 100 is fixed to the tip of the wire 98, and the wire 98 is wound around the annular groove 95 with the ball 100 fitted into the ball holding portion 96 of the wheel 83.

As described above, the wheel 83 and the movable clutch 86 are configured to be able to move relative to each other in the axial direction and rotate together through key engagement.

Under normal conditions, the movable clutch 86 is biased by the spring 85 and engaged with the fixed clutch 90, so the elastic adjustment handle 48 and the wheel 83 rotate together, but the wire 98 cannot be pulled. When the wheel 83 stops rotating, the movable clutch 86 moves backward against the spring 85, and the elastic adjustment handle 48 rotates idly.

As shown in FIGS. 11(C) and 8(A), a wheel 102 having an annular groove 101 formed on the outer periphery is integrally (or separately) formed on the upper surface of the cam 56. The wheel 102 includes two ball holding parts 103 that communicate with the annular groove 101 and are open upward. Furthermore, a pair of front and rear tube holding portions 104 are formed on the right inner side of the base 5 . An end fitting 99 provided at the end of a tube (not shown) through which a wire 98 is inserted is attached to the tube holding portion 104. An end fitting 99 provided on the base 5 is held by the upper cover 66 so as not to be detachable.

(6).Summary The spring unit 54 moves up and down along the load receiving arm 53, and as the load supporting span of the load receiving arm 53 changes, the resistance to the backward tilting of the backrest 3 changes. As can be understood from FIG. 5(B), no matter where the rear end of the spring unit 54 contacts the load receiving arm 53, the tangent at the contact position and the axis of the spring unit 54 are perpendicular to each other. Therefore, basically, the force of the spring built into the spring unit 54 does not act to rotate the spring unit 54.

Therefore, no force acts on the interlocking member 59 to inhibit its movement, and no force acts on the cam 56 to rotate it in either direction. As a result, the posture of the spring unit 54 can be stably maintained. In this embodiment, the rotation of the cam 56 is converted into the forward and backward movement of the interlocking member 59 to rotate the spring unit 54, so it is easily possible to make the cam 56, which is a circumferential cam, horizontally rotatable. . Therefore, the vertical height of the portion where the cam 56 is arranged can be made as low as possible, and the support mechanism of the chair can be made compact.

Now, as mentioned above, basically, the setting is such that no force is applied to the spring unit 54 to rotate it upward, but due to the relationship with the front profile of the load receiving arm 53, the force that causes the spring unit 54 to rotate upward is not applied. It is assumed that it exhibits a tendency to rotate upward. In this case, the upward rotation of the spring unit 54 acts as an upward load on the interlocking member 59 and the slider 57, and does not act as a torque to rotate the cam 56, and the interlocking member 59 and the slider 57 Since the upper cover 66 holds it so that it cannot move upward, no problem occurs.

After all, since no external force is applied to the cam 56 to rotate it, the cam 56 can be stably held even when the support protrusion 70 of the interlocking member 59 is brought into contact with the cam 56 as in the embodiment. Therefore, by increasing the number of cam surfaces 71 to 79, the elasticity can be finely adjusted. The advantages of forming the cam surfaces 71 to 79 in recesses are as described above.

Regarding the rotation of the cam 56, for convenience, rotation in a direction that increases the inclination angle of the load receiving arm 53 is defined as normal rotation, and rotation in a direction that decreases the inclination angle of the load receiving arm 53 is defined as reverse rotation. Sometimes one wire 98 pulls the cam 56 and the other wire 98 pulls the wheel 83 of the operating unit 80, and when reversing, the other wire 98 pulls the cam 56 and one wire 98 pulls the wheel 83. Wheel 83 of unit 80 is pulled.

That is, when the elastic adjustment handle 48 is rotated, tensions are applied to the two wires 98 simultaneously in opposite directions. Therefore, the cam 56 can be accurately rotated by rotating the elastic adjustment handle 48. It is also possible to use one wire and lock both ends of the wire 98 to the wheel 83 of the operating unit 80 and wrap the middle part around the wheel 83 provided on the cam 56. In this case as well, the elastic The cam 56 can be rotated by rotating the adjustment handle 48 in either direction, but if two wires are used as in the embodiment, the cam 56 can be rotated without causing a slipping phenomenon between the wheel 83 and the wire 98. can be rotated accurately.

Now, in this embodiment, once the cam 56 has rotated in either the forward or reverse direction, it cannot rotate any further, but the user may not notice that the cam 56 has rotated completely. Furthermore, it is assumed that the elastic adjustment handle 48 is rotated in order to rotate the cam 56 in the forward or reverse direction. For this reason, if no measures are taken, there is a fear that excessive tension will act on the wire 98, causing the wire 98 to come off from the member and the wheels 83, 102, etc. to be damaged.

In this regard, if the operating unit 80 is provided with clutches 86 and 90 as in this embodiment, it is possible to prevent excessive tension from being applied to the wire 98, thereby preventing damage to the members.

(7).Modification FIG. 12 shows another example of the rotation operation mechanism of the spring unit 54 using the cam 56, which is a specific example of claim 6. This embodiment is basically the same as the previous embodiment, and includes a cam 56 that horizontally rotates in both forward and reverse directions by pulling two wires, and an interlocking member 59 that moves forward and backward in conjunction with the cam 56. It is equipped with

In this example, a bracket frame 105 having longitudinal longitudinal holes is integrally provided on the upper surface of the spring case 54a, and the front end portions of the interlocking member 59 are connected with left and right longitudinal connecting pins 58. The interlocking member 59 has a cutout groove 106 into which the bracket frame 105 fits.

A backward projecting portion 107 is provided at the lower end of the left and right middle portion of the rear end of the interlocking member 59, and a circular engagement protrusion 108 is provided on the backward projecting portion 107 to project upward. An engagement groove 109 is formed on the lower surface of the outer circumference of the cam 56 so that its outer circumferential portion overlaps with the engagement protrusion 108, and is elongated in the circumferential direction into which the engagement protrusion 108 is slidably inserted. To be precise, the engagement groove 109 is formed in the range of the cam 56 where the cam surfaces 71 to 79 are formed. The engagement protrusion 108 and the engagement groove 109 are examples of the engagement portion described in the claims.

Although not shown, the interlocking member 59 is held by a cover so as not to be able to move upward, similar to the previous embodiment. The engagement protrusion 108 of the interlocking member 59 and the engagement groove 109 of the cam 56 are always held in a fitted state. Therefore, even if the cam 56 rotates in either the forward or reverse direction, the interlocking member 59 moves back and forth in conjunction with the rotation of the cam 56. Therefore, the attitude of the spring unit 54 can be accurately changed without causing a phenomenon in which the cam 56 rotates during reverse rotation and the interlocking member 59 does not retreat. Further, in this example, since the spring 67 and slider 57 used in the previous embodiment are not required, there is an advantage that the structure can be simplified.

In this example, the engagement protrusion 108 is provided to protrude upward and the engagement groove 109 is opened downward, but the engagement groove 109 is formed on the upper surface of the cam 56 and the engagement protrusion 108 is provided to protrude downward. It is also possible to do so. Note that instead of the engagement groove 109, it is also possible to provide a downward or upward rib along the outer circumference of the cam 56 (in the engagement groove 109, the outer circumferential surface functions to prevent the interlocking member 59 from separating). (The inner peripheral surface is not necessarily necessary, so the rib alone is sufficient.)

Although the embodiments of the present invention have been described above, the present invention can be embodied in various other ways. For example, it is also possible to directly connect the interlocking member 59 to the spring case without providing the slider 57 on the interlocking member 59. Furthermore, the present invention can also be applied to fixed chairs. As the cam operating means, a non-wire method such as a worm gear can also be adopted. An end cam can be used as the cam.

The present invention can be embodied in a chair. Therefore, it can be used industrially.

2 Seat 3 Backrest 5 Base 6, 14 Tilt frame 23 Seat support plate (seat outer shell)
24 Intermediate member 24a Bank part (side frame part)
40 Gas cylinder for tilt control 48 Elastic adjustment handle 50 First support shaft 53 Load receiving arm 54 Spring unit 54a Spring case 54b Movable spring receiver 56 Cam 57 Slider 59 Interlocking member 67 Operation spring 70 Support projections 71 to 79 Cam surface 80 Operation unit 82 Holder 83 Wheel of operation unit 86 Movable clutch 90 Fixed clutch 98 Wire 102 Wheel provided on cam

Claims (6)

The leg device includes a base provided at the upper end of the leg device, a spring unit disposed on the base to elastically support backward tilting of the backrest, and a pushing member that applies a load due to the backward tilting of the backrest to the spring unit. death,
The spring unit and the pushing member rotate about the left and right longitudinal axes, and by rotating the spring unit using an elasticity adjustment device and changing the abutment position with respect to the pushing member in the vertical direction. , a configuration that changes resistance to backward tilting of the backrest,
The elasticity adjusting device includes a cam that rotates when a handle is operated, and an interlocking member that moves due to the rotation of the cam and rotates the spring unit, and the elasticity adjustment device has a direction in which a force is applied to the interlocking member and an interlocking member that rotates the spring unit. The direction of action of the force of the interlocking member is different.
Chair. The interlocking member is attached to the base so as to be movable back and forth, and the side view posture of the spring unit is changed by the back and forth movement of the interlocking member.
The cam is a circumferential cam, and is disposed behind the interlocking member and is horizontally rotatably attached to the base.
A chair according to claim 1. A swinging head is connected to the front end of the interlocking member via a left and right longitudinal shaft, and the head is attached to the top surface of the spring unit so as to be slidable back and forth.
A chair according to claim 2. The cam is provided with a wheel on which a wire is locked or wound, and the rotation of the handle is transmitted to the rotation of the cam via the wire.
A chair according to any one of claims 1 to 3. The wire is connected to a rotor concentric with the handle, and a clutch is interposed between the handle and the rotor to cause the handle to idle when the cam is completely rotated in either direction.
A chair according to claim 4. The interlocking member and the cam are provided with an engaging portion that allows mutual movement and holds them so that they cannot be separated back and forth.
The chair according to claim 2 or 3.

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