JP2021100456A - Back rest locking range adjustment mechanism and chair - Google Patents

Abstract

To provide a back rest locking range adjustment mechanism for a chair in which a mechanical part under a seat can be miniaturized.SOLUTION: There is provided a back rest locking range adjustment mechanism comprising: a back rest reaction force mechanism 50 which generates, between itself and a main frame, the force for pressing and returning a back rest in linkage with the rearward tilt of a back rest, and uses a spring 41 for applying the force to a back support rod; and a locking range adjustment mechanism 51 which is arranged concentric to the spring 41. The locking range adjustment mechanism 51 comprises: a movable member 34 which contacts the back support rod for moving in an axial direction of the spring 41 in linkage with locking of the back rest; and a switching member 33 which is not capable of moving in the axial direction and is rotatable around the axis and is held to the main frame. The switching member 33 and the movable member 34 are arranged so as to face each other coaxially with the spring 41, and by rotation of the switching member 33, a minimum interval between end faces 35, 38 can be varied. By abutting the minimum-interval portions, movement of a member in linkage with the back rest can be inhibited for regulating a locking range, and by extending the interval between the minimum-interval portions, the locking can be allowed.SELECTED DRAWING: Figure 4

Description

The present invention relates to a backrest locking range adjusting mechanism and a chair. More specifically, the present invention relates to a locking range adjusting mechanism and a chair that allow the lockable range of the backrest of the chair to be adjusted.

Conventionally, there have been chairs provided with a locking range adjusting mechanism that allows the locking range of the backrest to be adjusted. For example, in a chair in which the seat and backrest are synchronized and locked between the standing posture and the backward leaning posture, the seat is directly supported by a support (main frame) on the leg so as to be slidable in the front-rear direction. A regulatory member that acts to regulate the sliding range of the shaft so that it can be changed, an operation member that operates the regulation member, a transmission shaft that transmits the operating force of the operation member to the regulation member, and the regulation member as an axis. There is one provided with a retracted position that does not regulate the slide range of the shaft and a click stop mechanism that fixes the slide range of the shaft at a plurality of regulated positions (Patent Document 1).

Japanese Unexamined Patent Publication No. 2004-33444

However, the locking range adjusting mechanism described in Patent Document 1 requires a large-scale mechanism in the mechanical portion, resulting in an increase in the size of the mechanism. In this case, the mechanical part under the seat becomes large, and a simple and neat appearance cannot be obtained. In addition, the configuration is premised on synchro rocking in which the backrest is locked in synchronization with the seat, and is a mechanism that cannot be used in the case of mere backrest locking or a weight sensing mechanism.

An object of the present invention is to provide a backrest locking range adjusting mechanism and a chair capable of downsizing the mechanical portion under the seat.

The backrest locking range adjusting mechanism for achieving such an object is a locking range adjusting mechanism that regulates the locking range of the backrest of a chair having a locking function in which the backrest falls backward, and is linked to the backward tilt of the backrest. The backrest reaction force mechanism using a spring that generates a force to push back the backrest with the main frame and applies it to the member that works with the backrest, and the backrest reaction force mechanism are arranged concentrically with the spring. It is equipped with a locking range adjustment mechanism that moves in the axial direction of the spring in conjunction with the locking of the backrest by contacting the member that interlocks with the backrest, and the locking range adjustment mechanism moves in the axial direction. It has a switching member that is impossible and rotatably held by the main frame around the axis, and the switching member and the movable member are arranged so as to face each other coaxially with the spring, and the switching member and the switching member are rotated by the rotation of the switching member. The minimum distance between the end faces facing each other with the movable member is variable, and by abutting the minimum distance parts, the movement of the interlocking member is blocked, the locking of the backrest is regulated, and the distance between the minimum distance parts is widened. Allows rocking of the backrest.

Here, a convex portion that protrudes in the axial direction is formed on either one of the end faces of the switching member or the movable member that face each other, and a concave portion through which the convex portion enters is formed on the other, and the convex portion is the other member. By contacting the end face, the movable member is prevented from moving in the axial direction to regulate the locking range of the backrest, while the movable member can be moved in the axial direction at the position where the convex portion enters the concave portion to enable the locking of the backrest. Is preferable.

Further, while the end face of the movable member is provided with a convex portion, the end face of the switching member is provided with a concave portion, and the tip surface of the convex portion abuts on the end face of the switching member and functions as an end face to prevent its movement. It is preferable to release the locking regulation or switch the regulation by arranging either one of the per-degree end faces in front of the convex portion of the movable member.

Further, the locking restricted position is not limited to a specific position, but is preferably an initial position.

Further, it is preferable that the locking range adjusting mechanism is arranged outside the spring and covers the spring.

Further, it is preferable that the outer peripheral surface or the front end surface of the switching member is provided with a rotation operating means that penetrates the main frame and projects outward.

Further, the movable members include a spring mount receiver that supports the rear end of the spring of the backrest reaction force mechanism, a bearing portion that swingably engages with a member that interlocks with the backrest, and a mount pin receiver that holds the mount pin. It is preferable that the rear spring mount is also used.

Further, it is preferable that the chair incorporates the backrest locking range adjusting mechanism according to any one of claims 1 to 7.

According to the device according to claim 1, by configuring the locking range adjusting mechanism concentrically with the reaction force adjusting mechanism, the mechanical part under the seat can be miniaturized, space efficiency is improved, and a simple and neat appearance is achieved. Is obtained.

It is a perspective view seen from the bottom which shows one Embodiment of the chair to which this invention is applied. It is a perspective view seen from above which shows the main frame and the back support of the chair. It is a perspective view which shows one Embodiment of the spring type backrest reaction force mechanism and the locking range adjustment mechanism accommodated in the main frame of FIG. It is a perspective view of the backrest reaction force mechanism and the locking range adjustment mechanism of the same spring type. It is an exploded perspective view of the backrest reaction force mechanism and the locking range adjustment mechanism of the same spring type. It is a perspective view seen from the top of the main frame. It is a vertical cross-sectional view of a main frame, a backrest reaction force mechanism, and a locking range adjustment mechanism. It is a perspective view seen from the back surface side of the holding plate which holds a switching member. It is a perspective view which showed the 2nd Embodiment of this invention, which was seen from the bottom of the main frame, the spring type backrest reaction force mechanism, and the locking range adjustment mechanism. It is a perspective view which looked at the main frame, the spring type backrest reaction force mechanism, and the locking range adjustment mechanism which concerns on 2nd Embodiment from above. It is a top view which shows the main frame which shows the 3rd Embodiment of this invention, a spring type backrest reaction force mechanism, a locking range adjustment mechanism, and a back support rod. It is a top-view view which shows the main frame, the back support, and the locking range adjustment mechanism which concerns on 3rd Embodiment. It is a perspective view seen from the top of the main frame which concerns on the 3rd Embodiment. It is a perspective view of the spring-type backrest reaction force mechanism and the locking range adjustment mechanism which concerns on the 3rd Embodiment. It is an exploded perspective view of the backrest reaction force mechanism and the locking range adjustment mechanism of the same spring type. It is an exploded perspective view of the locking range adjustment mechanism.

Hereinafter, the configuration of the present invention will be described in detail based on the embodiments shown in the drawings. In this specification, the front-back and left-right directions are defined centering on the seated person, and "front or front" means the chair and the front of the seated person sitting on the chair in each of the seat and the backrest. Alternatively, it is forward-looking, and "rear or backward" is likewise backward or backward for the chair and the occupant. Further, the direction orthogonal to the front-rear direction and the horizontal plane is the left-right direction for the seated person in each of the seat and the backrest, and is the width direction of the chair. In addition, "above" and "below" are above and below the chair and seater in the seat and back, respectively, above and below in the vertical plane.

1 to 8 show an embodiment of a chair to which the present invention is applied. As shown in FIG. 1, for example, this chair includes a leg 1 having casters, a main frame 2 supported by the leg 1, and a seat 3 swingably supported by the main frame 2 and interlocking with each other. And the backrest 4, and a mechanism for adjusting the lockable range of the backrest by restricting the locking range of the backrest 4 at at least one place, for example, the initial position or other positions (referred to as a locking range adjusting mechanism 51). ) And. It should be noted that adjusting the locking range means that locking is not possible due to regulation at multiple positions, regulation at one position, or collision at the initial position (the position of the backrest when there is no seated person). Becoming is also included in the adjustment of the locking range.

Here, the backrest 4 is not limited to a specific structure and shape, but is, for example, a so-called total body in which an inner shell (not shown) is completely covered with a cushioning material and a bag-shaped upholstery. The back structure may be supported by a back support rod 5 that is swingably connected to the main frame 2. Similarly, the seat 3 is not limited to a specific structure and shape, but for example, the inner shell is completely covered with a cushioning material (not shown) and a bag-shaped upholstery. As a seat structure of the whole body, it is mounted swingably by being supported by the main frame 2 and the back support rod 5.

In the case of the present embodiment, the back support rod 5 has an L-shape that is placed horizontally, for example, as shown in FIG. 2, and the back mounting plate 8 is provided on the short side extending upward, while the backrest 4 is attached. , The front part on the long side extending forward is swingably connected to the main frame 2 by the backrest rotation shaft 6, and the part on the front side of the backrest rotation shaft 6 (hereinafter referred to as the arm portion 32). The structure is such that one of the spring mounts of the backrest reaction force mechanism 50, for example, the rear spring mount 43, is supported by the reaction force receiving shaft 7 at the tip of the above.

In the case of the present embodiment, the seat 3 is provided with, for example, a pair of brackets 13 and 14 on the back surface side of the outer frame on both the front portion and the rear portion, respectively, and a connecting shaft penetrating the elongated hole 12 on the front end side of the main frame 2. 9 and a rotation shaft 10 penetrating the bracket 15 formed on the rear side of the backrest rotation shaft 6 of the back support rod 5 are attached to each other, and the seat is interlocked with the swing of the back support rod 5. 3 is supported so that the rear side moves up and down (moves up and down) while moving back and forth.

Here, in the case of the present embodiment, the main frame 2 has left and right side wall portions as shown in FIG. 6, for example, in order to increase the mechanical rigidity as a structure, particularly the torsional rigidity, and to accommodate the reaction force mechanism inside. A bearing hole 24 formed in a box shape having 27 and a bottom wall portion 26, through which a tubular portion 23 into which a gas spring of a leg 1 is fitted and a backrest rotating shaft 6 are inserted and swingably connected. Is provided. In the present embodiment, for example, a steel material or the like is welded to form a box shape, but the present invention is not particularly limited to this, and may be integrally molded by aluminum die casting or the like.

The backrest reaction force mechanism 50 including the compression coil spring 41 is housed in the main frame 2, and the reaction force receiving shaft 7 at the tip of the arm portion 32 of the back support rod 5 and the support shaft 11 on the front end side of the main frame 2 The spring 41 is supported between the springs 41, and when the backrest 4 tilts backward, the rear spring mount 43 is pushed forward to compress the spring 41, thereby generating a force / reaction force to push the backrest 4 back. It is provided as follows.

In the case of the present embodiment, the backrest reaction force mechanism 50 includes a reaction force spring, for example, one compression coil spring 41, front and rear spring mounts 42 and 43 arranged at the front and rear ends thereof, and a spring, as shown in FIG. It is composed of a mount pin 44 for preventing buckling of the 41, and receives a reaction force at the tip of the front support shaft 11 of the main frame 2 and the front arm portion 32 of the back support rod 5 via the spring mounts 42 and 43. It is mounted between the shaft 7 and the shaft 7. Then, in conjunction with the backward tilt of the backrest 4, a force for pushing back the backrest 4 is generated in the spring 41 between the main frame 2 and the spring 41, and a member interlocking with the backrest 4 (in the case of the present embodiment). Is given to the back support 5).

In the case of the present embodiment, the front spring mount (hereinafter referred to as the front spring mount 42) includes, for example, as shown in FIG. 5, a disc-shaped spring mount receiver 46 that supports the spring 41 and a support shaft 11. The spring mount receiver 46 is composed of a bifurcated bearing portion 47 for swinging with respect to the spring 41 and a tubular mount pin receiving portion 45 that is fitted inside the spring 41 to support the mount pin 44. The tip of the spring 41 is supported and supported, and the tip side of the mount pin 44 is fitted and supported by the mount pin receiving portion 45. The front spring mount 42 is swingably supported by using a support shaft 11 fixed to the main frame 2.

On the other hand, in the case of the present embodiment, the rear spring mount (hereinafter referred to as the rear spring mount 43) accommodates and supports the other end side of the spring 41, for example, a cylindrical spring mount receiver (locking range adjusting mechanism 51). It also serves as a movable member 34), a bifurcated bearing portion 47 for swinging with respect to the reaction force receiving shaft 7, and a cylindrical mount pin receiving portion 45 for supporting the mount pin 44. There is. The spring mount receiver that also serves as the movable member 34 and the mount pin receiving portion 45 are in a double-cylinder state, and the mount pin 44 is accommodated in the hole 48 of the mount pin receiving portion 45 and the spring 41 is stored in the space around the mount pin receiving portion 45. Is accommodated and supported so as to be movable in the front-rear direction in conjunction with the arm portion 32 of the back support rod 5. That is, in the case of the present embodiment, the bottom portion 49 of the movable member 34 functions as a spring mount receiver.

Here, around the spring 41 of the backrest reaction force mechanism 50, as shown in FIG. 4, the locking range of the backrest 4 is regulated at the initial position or other positions so that the backrest 4 can be locked. The locking range adjusting mechanism 51 for adjusting the above is arranged concentrically.

The locking range adjusting mechanism 51 moves in the axial direction of the spring 41 in conjunction with the locking of the backrest 4 by coming into contact with the member (in the case of the present embodiment, the back support 5) interlocking with the backrest 4. It has a movable member 34 and a switching member 33 that is immovable in the axial direction and is rotatably held by the main frame 2 around the axis, and the switching member 33 and the movable member 34 are coaxial with the spring 41. They are arranged so as to face each other, and are configured to regulate the movement of the backrest 4 by abutting the switching member 33 and the movable member 34. That is, the rotation of the switching member 33 makes the minimum distance between the opposing end faces of the switching member 33 and the movable member 34 variable, and the minimum distance portions are abutted to prevent the movement of the interlocking member / back support rod 5. Therefore, the locking range of the backrest 4 is regulated, and the locking of the backrest 4 is allowed by widening the interval of the minimum interval portion.

In the case of the present embodiment, one of the switching member 33 and the movable member 34, for example, the movable member 34 has a convex portion 37 protruding in the axial direction, and the other, for example, the switching member 33 has an end face (per degree). The end face) 35 and the concave portion 36 into which the convex portion 37 enters are formed, and the convex portion 37 abuts on the end face 35 of the other member to prevent the movable member 34 from moving in the axial direction and the locking range of the backrest 4. On the other hand, the movable member 34 can be moved in the axial direction at the position where the convex portion 37 enters the concave portion 36, and the backrest 4 can be locked. That is, by rotating the switching member 33, either the concave portion 36 of the rotation switching member 33 or the per-degree end face 35 is arranged in front of the convex portion 37 of the movable member 34, so that the locking regulation is released or regulated. It has a structure that can be switched.

The switching member 33 switches the position where the convex portion 37 of the movable member 34 abuts, in other words, the position where the movement of the movable member is blocked or the range in which the movable member can move back and forth. In the case of the present embodiment, the switching member 33 has at least two stages (two stages of the tip surface 35 and the bottom surface 36a of the recess 36), preferably three stages (three stages of the end surface 35 and the bottom surfaces 36a and 36b of the recess 36). The above-mentioned hitting surface is set. For example, in the case of the present embodiment, as shown in FIG. 5, it has a tip surface 35 and two bottom surfaces 36a and 36b of a recess 36 that is recessed with respect to the tip surface 35, and is directed toward the switching member 33. It is provided so as to limit the movement of the movable member 34 that moves in close proximity. That is, when the convex portion 37 protruding in the axial direction of the movable member 34 abuts on the innermost portion (bottom surface 36a) of the concave portion 36 of the switching member 33, the amount of axial displacement becomes the largest and when it abuts on the tip surface 35. The amount of axial displacement is the smallest, and the amount of axial displacement is intermediate when it hits the intermediate step (bottom surface 36b). Further, before the convex portion 37 of the movable member 34 abuts on the innermost portion (bottom surface 36a) of the concave portion 36 of the switching member 33, the end surface 35 of the switching member 33 and the end surface 40 of the movable member 34 abut and lock the backrest. You may try to prevent.

In the case of the present embodiment, the switching member 33 adopts a tubular structure that allows the spring 41 and the front spring mount 42 to pass through, and the switching operating means 39 (for example, the operating lever 39 _L ) projects radially outward on the peripheral surface. It is provided inside the main frame 2 as described above. The main frame 2 is provided with a window 16 on the side wall portion 27 for popping out the _{operation lever 39 L} , and the switching member 33 is operated by operating the _{switching lever 39 L that penetrates the window 16 and projects outward.} The rotation is done. The switching member 33 includes a pair of front and rear arc-shaped rails (recesses) 17 that cross between the four vertical ridges 19 formed on the inner surface side of the side wall portion 27 and the left and right ridges 19 in the width direction. It is housed in a space partitioned between the two, and is rotatably held by a holding plate 22.

The presser plate 22 is, for example, a rectangular frame material having a hollow portion in the center when viewed from above, and surrounds the vicinity of the top of a cylindrical switching member 33 laid on the bottom wall portion 26 of the main frame 2. It is arranged in the main frame 2 and fixed by a bolt 25 screwed into the female screw 20 of the four ridges 19 of the side wall portion 27 of the main frame 2. The bottom wall portion 26 of the main frame 2, the ridges 19, and the pressing plate 22 rotatably support the switching member 33 while positioning in the axial, width, and height directions, and the locking range adjusting mechanism 51 and thus the locking plate 22 are positioned. The backrest reaction force mechanism 50 is stably maintained.

As shown in FIG. 8, an arcuate rail (recess) 17 along the circumferential surface of the switching member is provided on the back surface side of the pressing plate 22 at a position where the edge portions of the front and rear ends of the switching member come into contact with each other. A crescent-shaped stepped portion 18 is formed. Therefore, between the arc-shaped rail (recess) 17 formed in the bottom wall portion 26 of the main frame 2 and the substantially crescent-shaped stepped portion 18, the edge of the cylindrical switching member 33 housed inside the arc-shaped rail (recess) 17. The part is hooked to support it so that it can rotate smoothly while preventing movement in the front-back direction and in the left-right and up-down directions.

In the case of the present embodiment, the locking range adjusting mechanism 51 makes the minimum distance between the switching members 33 coaxially opposed to the compression spring 41 and the end faces 35 and 38 facing each other of the movable member 34 variable, and mutually. When the opposing end faces 35 and 38 come into contact with each other, the movement of the back support 5 and thus the backrest 4 is blocked, and when the convex portion 37 is switched to a position where it can enter the concave portion 36, the convex portion is formed on the bottom surface 36a or 36b of the concave portion. The movement of the movable member 34 until the 37 comes into contact with the movable member 34, in other words, the movement of the back support 5 and thus the backrest 4 is allowed.

Therefore, the spring force 41 supported by the front spring mount 42 penetrating the switching member 33 and the rear spring mount 43 integrated with the movable member 34 expands and contracts due to the swing of the back support rod 5, and the spring force is increased. It is given to the back spring 5. On the other hand, _{the switching member 33 is rotated by the rotation operation of the operating lever 39 L to} the locking restricted position side, so that the tip 38 of the convex portion 37 of the movable member 34 is switched from the end surface 35 of the switching member 33 to the position of the concave portion 36. .. As a result, the minimum distance between the end faces 36a or 36b and 38 facing each other between the switching member 33 and the movable member 34 is widened, so that the spring can be further contracted. That is, the backrest is held until the minimum distance between the switching member 33 and the movable member 34, for example, the tip surface 38 of the convex portion 37 of the movable member 34 and the bottom portion 36a or 36b of the concave portion 36 of the switching member 33 are abutted against each other. Allows locking. That is, the locking range adjusting mechanism 51 is in the locking restriction release state.

On the other hand, when the backrest 4 is returned to the initial position (the position where the movable member 34 is most retracted) _{, the movable member 34 is rotated by the rotation operation of the operating lever 39 L to} the locking restricted position side, so that the movable member 34 is rotated. The tip surface 38 of the convex portion 37 of the 34 is switched to a position where it abuts on the end surface 35 of the switching member 33, and the tip surface 38 of the convex portion 37 deviates from the position of the concave portion 36 and abuts on the end surface 35 of the switching member 33. As a result, the gap between the switching member 33 and the movable member 34 is almost eliminated, and the spring 41 can hardly be contracted. That is, the locking is restricted. Since the movable member 34 moves back and forth in conjunction with the movement of the arm portion 32 of the back support rod 5 by the force of the spring 41, the movable member 34 retracts when the backrest 4 returns to the initial position.

Here, by setting the concave portion 36 of the switching member 33 or the convex portion 37 of the movable member 34 in a stepwise depth or height, not only the locking regulation at the initial position but also the two steps including the intermediate position are included. It is also possible to provide the above locking regulation positions. For example, as shown in FIG. 5, when two axial end surface positions of the tip surface 35 and the bottom surfaces 36a and 36b of the recess 36 which is a recess with respect to the tip surface 35 are provided, the movable member 34 The amount of axial displacement is the largest when the convex portion 37 protruding in the axial direction is fitted into the innermost portion of the concave portion 36 of the switching member 33, and the amount of axial displacement is the smallest when it comes into contact with the surface of the end face of the shaft. Further, when fitted to the intermediate step portion, the amount of axial displacement is medium.

In the above-described embodiment, the operating lever 39 _L , which is the operating means of the switching member 33, is projected outward from the window 16 opened in the side wall portion 27 of the main frame 2, that is, the lateral operation type. The structure is not particularly limited, and as shown in FIGS. 9 and 10, for example _{, as a structure in which the operation lever 39 L} of the switching member 33 projects outward from the window 16 opened in the bottom wall portion 26 of the main frame 2, that is, as a lower operation type. Is also good. In this case, the main structures of the switching member 33 and the movable member 34 are common, only the position of the window 16 of the bottom wall portion 26 of the main frame 2 and _{the mounting position of the operating lever 39 L with respect to the switching member 33 are different.} , Detailed description will be omitted.

Further, the switching operation means 39 is not limited to the case where it protrudes from the side surface or the bottom surface of the main frame 2 as described above. For example, as shown in FIGS. 11 to 16, the operation knob 39 _N is placed on the front wall of the main frame 2. It is also possible to have a structure in which the portion 30 is projected to be operated from the front. Of course, in this case, a disk-shaped knob-type operating means as shown in the figure, that is, an operating knob 39 _N may be used, but instead of this, a lever is provided and the switch can be switched by distributing (rotating) to the left or right. Is also good.

In this embodiment, as shown in FIG. 13, the main frame 2 is provided with a partition wall portion 28 that supports the front end of the spring 41 and a front wall portion 30 that prevents the switching member 33 from moving in the axial direction. The partition wall 28 is provided with a hole 29 through which the switching member 33 penetrates, and the front wall portion 30 is provided with a hole 31 that allows _{the connecting shaft / screw (not shown) of the operation knob 39 N} to pass through but prevents the switching member 33 from passing through. Is provided. _{The holes 31 and 29 are arranged coaxially with each other, and penetrate the operation knob 39 N} through the main frame 2 in a state where the front end surface of the switching member 33 penetrating the partition wall portion 28 is in contact with the inner wall surface of the front wall portion 30. It can be installed by letting it. That is, as shown in FIGS. 14 and 15, the switching member 33 of the present embodiment forms a rod shape that penetrates the partition wall portion 28 and abuts on the front wall portion 30, and is operated to the front end through the hole 31 of the front wall portion 30. By screwing in the knob 39 _N , the knob 39 N is assembled so as to be immovable in the axial direction with respect to the main frame 2 and rotatably around the axis.

Therefore, the backrest reaction force mechanism 50 of the present embodiment includes a reaction force spring, for example, one compression coil spring 41, a rear spring mount 43 arranged at the rear end, and a front spring mount that supports the front end of the compression coil spring 41. A back support that is composed of a partition wall 28 of the main frame 2 that functions as a function and a mount pin 44 for preventing buckling of the spring 41, and is linked by interposing the partition wall 28 of the main frame 2 and the rear spring mount 43. It is mounted between the arm portion 32 of the rod 5 and generates a force for pushing back the backrest to the spring 41 in conjunction with the backward tilt of the backrest.

Here, the locking range adjusting mechanism 51 is incorporated inside the spring 41 as shown in FIG. The locking range adjusting mechanism 51 is composed of, for example, a combination of a movable member 34 having a convex portion 37, an end surface 35 facing the convex portion 37, and a switching member 33 having a concave portion 36, as in the above-described embodiment. By rotating the switching member 33 by a predetermined angle, the recess 36 (locking restriction release position) or the end face 35 (locking restriction position) is selectively arranged in front of the convex portion 37 of the movable member 34. In the present embodiment, the locking restricted position where the convex portion 37 of the movable member 34 and the end surface 35 of the switching member 33 abut is, for example, a state in which the backrest 4 is returned to the initial position (the movable member 34 is most retracted). Position) or the position immediately before it (bottom surface 36a of the recess 36), but is not particularly limited to this, and may be only the initial position or a plurality of other positions or both the initial position and the plurality of positions. It may be included.

The switching member 33 of the present embodiment has a rod shape, and the end face side facing the movable member 34 is formed in a cylindrical shape to form an end face 35 and a recess 36, and a mount pin 44 is inserted into the bottom of the cylindrical portion. A hole (not shown) is provided to support the tip of the mount pin 44. Therefore, the mount pin 44 is held between the rear spring mount 43 integrated with the movable member 34 and the switching member 33, while the spring 41 is held between the rear spring mount 43 and the partition wall 28 of the main frame 2. Be supported.

According to the locking range adjusting mechanism 51 of the present embodiment, when the operation knob 39 _N is rotated to the locking restricted position side, the concave portion 36 of the switching member 33 is arranged in front of the convex portion 37 of the movable member 34, and the convex portion 37 Can enter the recess 36. As a result, the distance between the switching member 33 and the movable member 34 is widened, so that the spring 41 can be moved in the direction of further contraction. That is, the locking of the backrest is in the locking restricted state.

On the other hand, when the operation knob 39 _N is rotated to the locking regulation position side, the concave portion 36 of the switching member 33 deviates from the front of the convex portion 37 of the movable member 34 and switches to the end surface 35, so that it is movable with the end surface 35 of the switching member 33. There is almost no gap between the member 34 and the convex portion 37, and the spring 41 can hardly be contracted. That is, the locking of the backrest is regulated at the initial position. Further, when the bottom / end surface 36a is switched to the middle portion of the recess 36, the spring 41 cannot be further compressed, and the position is switched to the locking restricted position state at the middle position.

According to the locking range adjusting mechanism 51 configured as described above, the backrest reaction force mechanism 50 and the locking range adjusting mechanism 51 are configured coaxially with the backrest reaction force mechanism 50 and the locking range adjusting mechanism 51. While providing the two mechanisms of, the space under the seat can be miniaturized, the manufacturing cost can be suppressed, and the appearance can be improved.

The above-mentioned form of the spring support structure is an example of a preferable form of the present invention, but the present invention is not limited to this, and various modifications can be carried out without departing from the gist of the present invention. For example, in the above-described embodiment, the concave portion 36 is provided on the side of the switching member 33 and the convex portion 37 is provided on the side of the movable member 34, but the structure is not particularly limited to this, and the convex portion 37 is provided on the side of the switching member 33. , The recess 36 may be provided on the side of the movable member 34.

Further, in the above-described embodiment, a plurality of stepwise bottoms 36a and 36b are formed in the recess 36 to enable locking regulation not only at the initial position but also during the locking operation, but this is not particularly limited. Instead, a step may be provided on the convex portion 37 to create a plurality of locking regulation positions. Further, in the above-described embodiment, the locking range adjusting mechanism 51 includes locking regulation at the initial position, but the locking range of the backrest is not particularly limited to this, and the locking range of the backrest is set at a position other than the initial position. You may.

In the above-described embodiment, an example applied to the reaction force applying mechanism 50 using the spring 41 has been described, but the chair to which the present invention is applied is not particularly limited to this, and the weight-responsive anti-chair is used. A chair that has only one of the application to the synchro locking mechanism that uses both the force applying mechanism and the reaction force applying mechanism that has a coil spring, or, for example, the seat moves backward while moving backward in conjunction with the backward tilting of the backrest. It can also be applied to a non-weight-sensing synchro locking mechanism in which the end side sinks, a locking mechanism in which only the backrest tilts backward alone, or a locking mechanism in which only the seat performs a locking operation, and even a chair without a locking mechanism. Needless to say, there is. Further, the specific shape and mode of each component such as the main frame 2, the seat 3, and the backrest 4 to which the present invention can be applied are not limited to those in the above-described embodiment, and the use and design of the chair are not limited to those in the above-described embodiment. It will be selected as appropriate based on such factors.

1 Leg 2 Mainframe 3 Seat 4 Back
5 Back support (member that works with the backrest)
6 Backrest rotation shaft 7 Backrest support member 8 Back frame 9 Back plate 10 Back mounting seat 11 Support shaft 16 Window 32 Arm part 33 Switching member 34 Movable member 35 End face 36 Recess 36a Bottom of recess 36b Bottom of step of recess 37 Convex 38 Convex end face 39 Rotational operating means 39 _L Operating lever 39 _N Operating knob 41 Spring 42 Front spring mount 43 Rear spring mount 44 Mount pin 45 Mount pin receiving part 46 Spring mount receiving 47 Bearing part 50 Backrest reaction force mechanism 51 Locking range adjustment mechanism

Claims (8)

In the locking range adjustment mechanism that regulates the locking range of the backrest of a chair having a locking function that allows the backrest to fall back.
A backrest reaction force mechanism using a spring that generates a force to push back the backrest with the main frame in conjunction with the backward tilt of the backrest and applies it to a member interlocking with the backrest.
A locking range adjusting mechanism arranged concentrically with the spring of the backrest reaction force mechanism is provided.
The locking range adjusting mechanism includes a movable member that moves in the axial direction of the spring in conjunction with the locking of the backrest by contacting with a member that is interlocked with the backrest, and a shaft that is immovable in the axial direction and is not movable in the axial direction. It has a switching member that is rotatably held by the main frame around it.
The switching member and the movable member are arranged coaxially with the spring so as to face each other, and the rotation of the switching member makes the minimum distance between the switching member and the movable end faces of the movable member variable. The feature is that the movement of the interlocking member is blocked by abutting the minimum spacing portions to regulate the locking of the backrest, and the locking of the backrest is allowed by widening the spacing of the minimum spacing portions. The backrest locking range adjustment mechanism of the chair. A convex portion that protrudes in the axial direction is formed on either one of the switching member or the end faces of the movable member that face each other, and a concave portion through which the convex portion enters is formed on the other, and the convex portion is the other member. By contacting the end face of the movable member, the movable member is prevented from moving in the axial direction to regulate the locking range of the backrest, while the movable member can be moved in the axial direction at a position where the convex portion enters the concave portion. The backrest locking range adjusting mechanism for a chair according to claim 1, wherein the backrest can be locked. The end surface of the movable member is provided with the convex portion, while the end surface of the switching member is provided with the concave portion, and the tip surface of the convex portion abuts on the end surface of the switching member to prevent its movement. The chair according to claim 2, which functions as an end face and releases or switches the locking restriction by arranging either one of the concave portion and the perforated end surface in front of the convex portion of the movable member. Backrest locking range adjustment mechanism. The chair backrest locking range adjusting mechanism according to any one of claims 1 to 3, wherein the locking restricted position is an initial position. The backrest locking range adjusting mechanism for a chair according to any one of claims 1 to 4, wherein the locking range adjusting mechanism is arranged outside the spring and covers the spring. The backrest locking range of a chair according to any one of claims 1 to 5, wherein a rotation operating means that penetrates the main frame and projects outward is provided on the outer peripheral surface or the front end surface of the switching member. Adjustment mechanism. The movable member includes a spring mount receiver that supports the rear end of the spring of the backrest reaction force mechanism, a bearing portion that swingably engages with a member that interlocks with the backrest, and a mount pin that holds the mount pin. The backrest locking range adjusting mechanism for a chair according to claim 5, which has a receiving portion and also serves as a rear spring mount. A chair incorporating the backrest locking range adjusting mechanism according to any one of claims 1 to 7.

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