JP2014210207A - Rocking chair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chair using rubber as elastic means for rocking, the chair being configured to securely hold rubber so that the rubber cannot be displaced even when the rubber is arranged near the rotation support point of a backrest and so that high elasticity is ensured despite the compact design thereof.SOLUTION: A chair comprises rubber 40 as elastic means that resists rocking. The rubber 40 is pressed by a main pressing member 38. The main rubber 40 is attached to a receiving member 41, in which a main recessed part 42 is formed for holding the rubber 40 such that the rubber 40 cannot be displaced. Rocking load is applied by a swinging member 18 via the main pressing member 38. In addition, the rubber 40 is arranged near a first shaft 19, which is the rotation support point of the swinging member 18. Thus, even in the case where the rubber 40 is arranged near the first shaft 19, the rubber 40 is accurately held in position without being pushed back.

Description

  The present invention relates to a chair using rubber as an elastic means for imparting resistance to rocking.

  The use of rubber as an elastic means for imparting resistance to rocking in a rocking chair is described in Patent Document 1, for example. In this patent document 1, the seat and the backrest are integrally connected, and a rectangular parallelepiped rubber is disposed between the base fixed to the upper end of the leg and the seat. Naturally, the rubber is arranged at a position (back) considerably away from the backrest and the pivot point of the seat. In addition, while a protrusion is provided on the lower surface of the rubber, a hole for receiving the protrusion of the rubber is received in the base, and the rubber is attached to the base so as not to be displaced by fitting the protrusion and the hole.

Japanese Utility Model Publication No. 43-13628

  Now, in office swivel chairs, coil springs and torsion bars are frequently used as elastic means, and rubber is not used much. This is because the rearward tilt angle of the backrest cannot be made very large when rubber is disposed at a position considerably away from the pivot point of the backrest as in Patent Document 1.

  On the other hand, in recent years, rubber having excellent elasticity and durability has been developed, and the inventors of the present application rotate the backrest greatly by placing the improved rubber close to the pivot point of the backrest. I was inspired to do it.

  In other words, the rubber is pinched between the base and the back support device, but as you can understand if you remember the heel, even if the amount of deformation of the rubber is the same, the rotation stroke of the backrest becomes closer as the rubber gets closer to the rotation fulcrum of the backrest Therefore, by placing rubber excellent in durability and elasticity close to the pivot point of the backrest, the back tilting stroke of the backrest is increased while using the rubber as an elastic means. It can be done.

  However, as a result of observation by the inventors of the present application, when rubber is in a state of being freely compressed and deformed by a load to expand its area, a phenomenon in which it is difficult to ensure a high elastic restoring force is observed. In order to avoid this, it is necessary to increase the size of the rubber, which makes it difficult to make it compact.

  Further, when the rubber is brought close to the pivot point of the backrest, an external force may be applied to the rubber to push it back, so that the position holding is not possible with the attachment means using the protrusion as in Patent Document 1. May be difficult. Moreover, when the protrusions are integrally provided on the rubber as in Patent Document 1, there is a problem that the processing cost increases.

  The present invention is based on the present situation, and is intended to provide a chair using rubber as an elastic means for rocking in a more improved form.

  The invention of claim 1 includes a base provided at the upper end of the leg, a seat disposed above the base, a back support device connected to the base so as to be tiltable rearwardly, and a backrest provided in the back support device; In a chair having a rubber for imparting resistance to the backward tilting of the back support device, the rubber being sandwiched between a first member and a second member that rotate relative to each other during locking, The rubber is fitted in a recess of a receiving member provided on either one or both of the first member and the second member so as not to be displaced.

  According to a second aspect of the present invention, in the first aspect, the receiving member provided on the first member or the second member is provided with a main receiving portion in which a main rubber that is initially loaded in an unlocked state is attached, and an elastic adjustment The sub-rubber or the movable sub-pressing member is operated by a lever. By selectively moving to the sub receiving portion and the relief portion, the resistance to rocking is adjusted.

  According to a third aspect of the present invention, in the first or second aspect, between the rubber and the receiving member, a ridge or a stopper pin extending in the same direction as the rotational axis of the back support device is interposed. In the surface where the rubber and the receiving member overlap each other, a recess into which the ridge or the stopper pin fits is formed.

  According to the present invention, since the receiving member regulates that the rubber spreads and deforms due to the load, in other words, the area where the rubber hits the receiving member does not change, and the portion fitted to the receiving member is restrained. Therefore, even if it is a compact rubber, a high elastic restoring force can be ensured. Thereby, it can be easily applied to a rocking chair having a rocking angle of about 15 to 20 °, for example.

  Now, for example, when rubber is sandwiched between the base and the back support device, the rubber is in a state of being pressed almost evenly from above and below if the rubber position is far from the pivot point of the back support device. When the rubber is brought close to the pivot point of the back support device, the back support device and the base form a lateral V shape in a side view so that the rubber is pushed backward by the pressure of the back support device and the base. Affected.

  However, in the present invention, since the rubber is installed on the receiving member so that it cannot be displaced, even if the rubber is disposed close to the pivot point of the back support device, it does not move backward, and its position is accurate. Retained. Therefore, according to the present invention, it is ensured that the rocking angle of the backrest is increased by bringing the rubber close to the pivot point of the back support device.

  Further, in the case of Patent Document 1, there is a possibility that the protrusion is broken and the rubber is displaced and dropped, but in the present invention, since the rubber is attached to the receiving member, it is accurately placed at a predetermined position. Retained. Therefore, the present invention is useful even when the rubber is arranged far away from the pivot point of the back support device. Further, the rubber can be arranged in a desired position and posture by adapting the structure of the receiving member.

  According to the second aspect of the present invention, the elasticity of the locking can be adjusted by moving the sub rubber or the sub pressing member. However, since the receiving member holds a part of the elasticity adjusting mechanism, the overall structure can be simplified. .

  Now, as described above, the back support device and the base are basically connected in a rearward opening V shape, so that uniform pressing can be realized if the rubber is formed into a fan shape or a trapezoidal shape in a side view. preferable. And even if the rubber is fan-shaped or trapezoidal when viewed from the side, it is inevitable that the rubber will be pushed backward by pressure from above and below, but in the present invention, the rubber is firmly held in place by the receiving member. Is done.

  Furthermore, when the invention of claim 3 is adopted, it is possible to remarkably reduce the effect of the rubber moving backward by pressurization by arranging the protrusion or stopper pin in the middle part of the front and rear of the rubber, Thereby, durability of rubber can also be improved.

(A) is a fragmentary perspective view of the chair which concerns on embodiment, (B) is a side view. FIG. FIG. It is the separation figure seen from the lower part. FIG. (A) is a partially separated perspective view of a movable rubber, (B) is a separated perspective view for showing a mounting structure of a back frame. It is a separate perspective view of the principal part. (A) is an exploded perspective view of the member, (B) is a perspective view with the receiving member turned upside down, and (C) is a partially broken perspective view of the base. FIG. It is a sectional side view in the location of fixed type rubber. (A) is a sectional side view at the location of the lock body, (B) is a sectional side view in a state where the movable rubber is disposed at a weak position. (A) is a separated plan view, (B) is a perspective view of the operation mechanism part. (A) is a perspective view of a back cover, (B) is a separated perspective view of an operation unit, and (C) is a partial perspective view of an operation mechanism section. (A) is a figure which shows 2nd Embodiment, (B) is a front sectional view of 2nd Embodiment, (C) is CC sectional view taken on the line of (B).

  Next, an embodiment of the present invention will be described with reference to the drawings. This embodiment is applied to a swivel chair used for office work or the like. In the following explanation and claims, the terms “front and rear” and “left and right” are used to specify the direction, but this term defines the direction in which a person sitting in a normal posture on a chair is facing forward. Yes. The front view is seen from the direction opposite to the seated person.

(1). Overview of the chair As shown in FIG. 1, the chair is composed of a leg device displaying only the leg strut (gas cylinder) 1, a base 2 fixed to the upper end of the leg strut 1, and a seat disposed above the base 2. It has a body 3 and a backrest 4 on which a seated person can rest. An armrest device can be attached to the base 2 as an optional item. As can be understood from FIG. 2, the seat body 3 has a seat plate (seat inner shell) 5 made of synthetic resin and a cushion material 6 arranged on the upper surface thereof, and the cushion material 6 has an outer skin such as a cloth. The material is stretched.

  As shown in FIG. 2, the backrest 4 includes a synthetic resin back frame 10 and a synthetic resin back plate 11 fixed to the front surface thereof. The back plate 11 is in the form of horizontal stripes with horizontally long holes, and a skin material 12 such as a mesh is stretched on the back plate 11. A cushion material may be disposed on the front surface of the back plate 11. In this case, the cushion material is covered with a bag-shaped skin material. The back frame 10 has a vertically long left and right side frame 13, an upper frame 14 that connects the upper ends thereof, and a lower frame 15 that connects the lower ends of the left and right side frames 13. A back plate 11 is fixed to the base plate.

  The back frame 10 includes left and right forward arm portions 16 extending in series from the side frame 13, and a joint portion 17 having an upper plate 17a and left and right side plates 17b is integrally connected to the left and right forward arm portions 16. . A swing member 18 made of a metal plate is connected to the rear portion of the base 2 so as to be tiltable by a left and right longitudinal first shaft 19, and the joint portion 17 of the back frame 10 is fixed to the swing member 18 with screws. . The left and right end portions of the first shaft 19 are exposed to the outside of the swing member 18.

  Therefore, in the present embodiment, the swing support member 18 and the back frame 10 constitute a back support device, and the backrest 4 tilts about the first shaft 19 (the first shaft 19 is pivotally supported by the backrest 4). It is an axis.) The swing member 18 and the back frame 10 can be configured integrally, the forward arm portion 16 can be a separate member from the side frame 13, or the swing member 18 and the forward arm 16 can be integrated. It is.

  The swing member 18 is integrally provided with a support arm 18a extending forward and upward in a tilted side view, and a rear engagement pin 20 is inserted through the distal ends of the left and right support arms 18a. For example, as shown in FIG. 5, a pair of left and right rear engagement claws 21 that are hooked and engaged with the rear engagement pin 20 from behind are integrally formed on the lower surface of the seat receiver 7. For this reason, when the backrest 4 tilts backward, the seat receiver 7 and the seat body 3 are pulled backward.

  On the other hand, for example, as shown in FIG. 5, the base 2 is made of a metal plate and has a box shape with an upward opening having left and right side plates 2 a, and a horizontally elongated second shaft 22 at the front thereof. The front link 23 having a single structure is rotatably connected to the second shaft 22, and the upper end of the front link 23 is rotated to the upper female fitting portion 24 formed on the seat receiving body 7. Inserted as possible. Therefore, when the seated person leans on the backrest 4, the seat receiving body 7 is pulled backward by the swing member 18, and the front link rotates accordingly, and the seat portion 8 moves upward while moving upward.

  As shown in FIG. 5, an upper cover 25 is mounted on the base 2 from above, and the rear engagement pin 20 is supported by the upper cover 25. The base 2 is covered with a lower cover 26 from below. A control unit 29 having an operation mechanism unit 27 and a back cover 28 is disposed at the rear of the base 2. By this control unit 29, switching of the resistance with respect to locking and regulation of the backward inclination of the backrest 4 are performed.

(2) Relationship between the base 2, the swinging member 18 and the back frame 10 Hereinafter, details of each part will be described. First, the relationship among the base 2, the swing member 18, and the back frame 10 will be described. As described above, the base 2 is in the form of a box that opens upward. For example, as shown in FIG. 5, the first inner bracket 31 having a U-shaped side opening downward at a substantially central portion of the inside of the base 2. The bush 32 is fixed to the inner bracket 31 and the bottom plate of the base 2, and the leg support 1 is fitted to the bush 32 from below.

  A second inner bracket 33 having a U-shaped upward opening is fixed to the first inner bracket 31 so that the base end portion of the armrest device is inserted into the space surrounded by the inner brackets 31 and 33 from the lateral direction. It has become. The left and right end portions of the second inner bracket 33 are exposed to the outside of the base 2, and a downward facing piece 33a is formed at the tip thereof, and the base end portion of the armrest device is fastened to the downward facing piece 33a with screws.

  The swing member 18 is a basic form having an upper plate and left and right side plates 18b. The base 2 is surrounded by the left and right side plates 18b from the outside. 19 penetrates. The first shaft 19 is attached to the base 2 via a bush. The support arm 18a of the swing member 18 extends from the side plate 18b.

  Left and right longitudinal frame receiving shafts 34 are inserted through the rear portions of the left and right side plates 18 b of the swing member 18. Both left and right ends of the frame receiving shaft 34 are exposed to the outside of the swing member 18. On the other hand, for example, as shown in FIG. 4, the forward arm portion 16 of the back frame 10 has a thick wall shape having a certain left and right width, and the front end of the forward arm portion 16 has an exposed end portion of the first shaft 19. A forward opening groove 35 to be fitted is formed, and further, a downward opening groove 36 that is fitted from the upper side to the distal end portion of the frame receiving shaft 34 is formed at a position behind the forward opening groove 35.

  As can be easily understood from FIG. 6B, the joint portion 17 of the back frame 10 overlaps the swing member 18 from above, and a resin-made main pressing member 38 is formed on the lower surface of the swing member 18. overlapping. The upper surface plate 17 a of the joint portion 17 and the upper surface plate of the swing member 18 are fastened with screws 37. As a result, the back frame 10 and the swing member 18 rotate together.

  When locked, the rear engaging claw 21 is pulled backward by the rear engaging pin claw 21, but the seat receiving body 7 must be pushed forward by the rear engaging pin 20 when the locking is returned. Therefore, although not shown, a stopper for holding the rear engaging pin 20 so as not to move relative to the front and rear is attached to the seat receiving body 7 by fitting from above.

(3). Arrangement Mode of Main Rubber For example, as shown in FIG. 10, a pair of left and right main rubbers 40 are arranged between the main pressing member 38 and the base 2, and the main rubber 40 is attached to the base 2. It is attached to the receiving member 41. Even in the non-locking state, the main rubber 40 is compressed by the main pressing member 38. That is, an initial load (pretension) is applied to the main rubber 40. The main rubber 40 and the receiving member 41 are disposed behind the pivot point of the swing member 18.

  Further, the main rubber 40 is disposed close to the first shaft 19, and for this reason, the swinging member 18 can be tilted backward at a large angle (for example, 15 to 20 °) by the compression of the main rubber 40. . Specifically, the first shaft 19 and the main rubber 40 have a space smaller than the radial dimension of the first shaft 19.

  The main rubber 40 has a fan-like block shape when viewed from the side, and is arranged so that the upper surface 39a and the lower surface 39b are located on the extension line of the axis of the first shaft 19 as shown by dotted lines in FIG. Yes. For this reason, each part of the main rubber 40 is evenly compressed by the main pressing member 38. In other words, the load accompanying pre-tensioning and locking acts equally on each part of the main rubber 40. For this reason, durability can be improved by eliminating one-sided contact.

  The receiving member 41 is made of resin, and has left and right main recesses 42 to which the left and right main rubbers 40 are mounted, for example, as shown in FIG. Between the left and right main recesses 42, a sub receiving portion 44 for receiving a sub rubber 43 (details will be described later) to make the resistance against locking strong, and the sub rubber 43 is released so that the sub rubber 43 is not compressed even when locked. The relief portion 45 is formed in a state where the right and left relief portions 45 are arranged side by side.

  As shown in FIG. 10, the bottom plate of the base 2 has a substantially horizontal posture, while the main rubber 40 has a substantially vertically symmetrical shape with a horizontal plane passing through the axis of the first shaft 19 in a side view. Therefore, the main recess 43 is inclined in a posture inclined backward with respect to the horizontal plane.

  The main recess 42 is surrounded by a rear rib 42a for holding the main rubber 40 so that it cannot be displaced backward and a side rib 42b for holding the main rubber 40 so that it cannot be displaced left and right. The sub receiving portion 43 is higher than the main recess 42. Therefore, the left main rubber 40 adjacent to the sub receiving portion 43 is a stopper that prevents the sub receiving portion 43 from moving inwardly of the main rubber 40. Plays the role of

  Therefore, the left main rubber 40 has only one side rib 42b, and is surrounded by the rear rib 42a, one side rib 42b, and the sub receiving portion 43 to form a recess. On the other hand, the right main recess 42 is surrounded by left and right side ribs 42b and one rear rib 42a. As shown in FIG. 6, a recess 42 into which the upper end portion of the main rubber 40 is fitted is also formed on the lower surface of the pressing member 38.

  For example, as shown in FIGS. 9 and 10, left and right horizontally elongated protrusions 46 are provided on the upper and lower surfaces of the main rubber 40. The protrusion 46 has a semicircular cross section, and a protruding receiving groove 47 having a circular cross section is formed on the lower surface of the main pressing member 38 and the upper surface of the main recess 42. The protrusions 46 are generally disposed at the front and rear intermediate portions of the main rubber 40, but may be provided at other portions. Further, it may be formed to extend in a direction orthogonal to the first shaft 19 and the axis.

  As described above, the sub receiving portion 44 has a height higher than that of the main recess 42, while the escape portion 45 is lower (deeper) than the upper surface of the main recess 42 as can be understood from FIG. 9, for example. . The bottom surface of the escape portion 45 is also set so that its extension line passes through the axial center of the first shaft 19 or the vicinity thereof in a side view.

  The receiving member 41 is a molded product of resin, and a large number of ribs (or voids) are formed on the bottom. As shown in FIG. 8B, the receiving member 41 has left and right positioning pins 48 projecting from the bottom surface thereof, while in FIG. 8B, a positioning hole 49 into which the positioning pin 48 is fitted is formed. ing. For this reason, the receiving member 41 is held so that it cannot be displaced and cannot be dropped without screwing. Of course, fixing with screws is acceptable.

  The main pressing member 38 is a resin product, and generally has a block-like appearance that is long in the left-right direction and has a square shape, but has many voids for lightening. Then, as shown in FIG. 11A, the joint portion 17 of the back frame 10 is fastened to the swing member 18 with screws 37.

  As shown in FIG. 8, a protrusion 38a is formed on the upper surface of the pressing member 38. On the other hand, as shown in FIG. 7, the swing member 18 is provided with a hole 18c into which the protrusion 38a of the pressing member 38 is fitted. Yes. Since the pressing force of the fixed rubber 40 is always acting as the pretension on the swing member 42, the fitting relationship between the protrusion 38a and the hole 18c is maintained. Therefore, the pressing member 38 is held so as not to be displaced without being fixed with screws. Of course, it is free to fasten with screws.

  In this embodiment, the base 2 and the swing member 18 are the first member and the second member described in the claims. Since the first member and the second member are relative concepts, whichever may be called the first, for convenience, the base 2 is an example of the first member and the swing member 18 is an example of the second member. In this embodiment, the pressing member 38 also functions as a receiving member.

(4). Operation Unit Lock Switching Device Next, the operation unit 29 will be described. First, the lock switching device will be mainly described. As described above, the operation unit 29 includes the operation mechanism unit 27 and the back cover 28 to which the operation mechanism unit 27 is attached.

  The back cover 28 includes left and right rib plate side plates 28a, and a vertically long left and right ter rib 28a has a holding portion 28b for attaching the back cover 28 to the frame receiving shaft 34 opened forward. The sandwiching portion 28b is fitted into the frame receiving shaft 34 by being deformed against elasticity.

  For example, as shown in FIG. 9, the back cover 28 is provided with a collar portion 28 c that overlaps the rear upper surface of the swing member 18, and the flange portion 28 c is fixed to the upper surface plate of the swing member 18. A recess 52 for accommodating the head of the screw 51 is formed in the collar portion 28c.

  For example, as can be understood from FIG. 12, the operation mechanism portion 27 has a central shaft 54 and an outer cylinder 55 covering the central shaft 54. The central shaft 54 constitutes an elastic adjustment device, and one end (right end) of the central shaft 54 protrudes outside the outer cylinder 55, and a strength adjustment lever 56 is attached thereto.

  On the other hand, the outer cylinder 55 constitutes a lock switching device, and a lock lever 57 is provided at one end (right end) thereof. Both levers 56 and 57 are arranged such that the strength adjustment lever 56 is located outside and the lock lever 57 is located inside. Further, the levers 56 and 57 are arranged with different postures in a side view so as to be easily operated by a person. One end portion of the outer cylinder 55 is a large-diameter portion 55 a, and the shaft portion of the strength adjustment lever 56 is rotatably held by the large-diameter portion 55 a, and the central shaft 54 is connected to the shaft portion of the strength adjustment lever 56. Fitted so that relative rotation is impossible.

  For example, as shown in FIG. 9, the left and right side end surfaces of the back cover 28 are provided with side plates 28d protruding forward in the upper half, and the outer ribs 28a described above are projected forward on the inner side of the side plates 28d. Yes. The side plate 28d overlaps the side plate 17b of the joint portion 17 in the back frame 10 from behind.

  A lock body 59 protruding from the axial center is integrally provided at the end of the outer cylinder 55 opposite to the lock lever 57, and an inner rib 60 sandwiching the lock body 59 from the left side is provided on the back cover 28. The inner end 55 b of the outer cylinder 55 is fitted into a bearing hole 61 formed in the inner rib 60. That is, the attaching portion of the lock body 59 is surrounded by the outer rib 28a and the inner rib 60 from the left and right sides. The outer rib 28a is formed with an engaging slot 62 into which the other end 55c of the outer cylinder 55 is fitted. The engagement slot 62 has a constricted shape with a narrow opening.

  As shown in FIG. 13, the other end portion 55 c of the outer cylinder 55 is formed with a Nusumi groove 63 whose outer peripheral surface is notched flat. The Nusumi groove 63 of the outer cylinder 55 is parallel to the engagement groove hole 62. By adopting the posture, it can be fitted into the engaging slot 62, and when it is fitted and rotated to the use posture, it is held so that it cannot be removed. A stopper piece 64 for preventing the outer cylinder 55 from moving inward is formed on the support portion 55c.

  The lock body 59 has a posture that protrudes substantially downward from the outer cylinder 55, and has two step portions of a first step portion 65 and a second step portion 66 facing the base 2. The 1st step part 65 is located in the front end side. On the other hand, first to fourth engagement grooves 67a to 67d are formed on the back surface of the lock body 59, and a stopper 68 is selectively fitted from behind to the engagement grooves 67a to 67d. It is supposed to be. The stopper 68 is attached to a pocket portion 69 formed in the back cover 28 so as to only move back and forth, and is urged in the forward direction by a block strip elastic body 70. As shown in FIG. 11A, an inward rib 71 that abuts against the central shaft 54 from the outside is provided at the other end of the outer cylinder 55 to ensure stable rotation.

  As can be understood from FIG. 11A, the lock body 59 can come into contact with the outward support flange 2 c provided on the rear wall 2 b of the base 3 from above. In FIG. 11A, the lock body 59 is in a locked posture in which the first step portion 65 is opposed to the upper surface of the support flange 2c. In this state, the backrest 4 is in a completely locked state in which the backrest 4 hardly tilts backward. Further, the stopper 68 is fitted in the second engagement groove 66b, so that the lock body 59 is held in the posture.

  When the outer cylinder 55 is rotated counterclockwise in the state of FIG. 11A, the lock body 59 has an intermediate posture in which the second step portion 66 faces the support flange 2c, and the second step portion 66 has the support flange 2c. Switch to a free posture facing the outside. In the intermediate posture, when the backrest 4 is tilted to a range of about half of the maximum tilt range, the second step portion 66 comes into contact with the support flange 2c, thereby restricting the back tilt range of the backrest 4 to about half of the maximum stroke. . In this intermediate posture, the stopper 68 is fitted in the third engagement groove 67c.

  Furthermore, in the free posture, the lock body 59 does not hit the support flange 2c during locking, and the backrest 4 can freely tilt within the maximum tilting range. In this free state, the stopper 68 is fitted in the fourth engagement groove 67d.

(5) Sub rubber of the operation unit Next, the sub rubber 43 of the operation mechanism 27 will be described. As described above, the sub-rubber 43 has the central shaft 54. For example, as can be understood from FIG. 13B, the front end portion of the central shaft 54 is supported by the other outer rib 28a of the back cover 28, and a snap ring 73 is attached to the front end to prevent it from coming off. In the center shaft 54, between the inner rib 60 of the back cover 28 and the other outer rib 28a, for example, as shown in FIG. 9 and FIG. The cam 75 is fitted.

  The slider 74 is slidably fitted to the central shaft 54 and protrudes forward, and the sub rubber 43 is mounted on the lower surface thereof. The slider 74 is opened downward, so that the sub rubber 43 is held so that it cannot be displaced in the left-right direction and the front-rear direction. Further, as shown in FIG. 13B, a groove 43a is formed on one side surface of the sub rubber 43, while a rib 74a that fits into the groove 43a is formed on the slider 74. ing.

  The slider 74 and the sub rubber 43 are slidably inserted in a space 76 formed in the main pressing member 38. The sub-rubber 43 also has a fan-like shape when viewed from the side. Further, the left and right guide projections 77 are provided at the tip of the slider 74, and the guide groove 78 in which the guide projection 77 is fitted is provided at the front end portion of the main pressing member 38, whereby the slider 74 and the sub rubber 43 are provided. Slides stably left and right without shaking up and down. The guide means may have another structure.

  For example, as shown in FIG. 12, the slider 74 has a cylindrical body 79 fitted to the central shaft 54, and a case portion 80 surrounding the cylindrical body 79. The case portion 80 has ribs 82 (see FIG. A) is held in a group slidable left and right. The case 80 is biased toward the strength adjustment lever 56 by a spring 83.

  The cylindrical body 79 is formed with a female cam groove 84 having a gap extending toward the strength adjustment lever 56 in a plan view, while the operating cam 75 holds the cylindrical body 79 from the outside. And has a cam surface 75 a that is tapered in plan view and overlaps with the female cam groove 84. The operating cam 75 is fixed to the central shaft 54 so as not to rotate relative to the central shaft 54 or to slide.

  Therefore, when the strength adjustment lever 56 is rotated, the slider 74 moves left and right by the guide action of the operating cam 75 and the female cam groove 84. A step portion 85 that engages with a flat portion 84 ′ at the opening edge of the female cam groove portion 84 is formed at the tip of the operating cam 75.

  As shown in FIG. 12A, in the retracted state where the female cam groove 84 is fitted to the operating cam 75, the slider 74 is held in the fitted state by the spring 83. In this state, the sub rubber 43 is positioned above the escape portion 45 of the receiving member 41, and therefore, the sub rubber 43 does not act as a resistance when locking. That is, the elasticity adjusting device is in a weak state where resistance to rocking is small.

  When the operating cam 75 is rotated in the direction of the arrow in FIG. 12B while the slider 74 is retracted by the spring, the slider 74 is pushed away from the strength adjustment lever 56 against the spring 83. The slider 74 is held in the advanced state by the step 85 of the operating cam 75 coming into contact with the opening edge of the female cam groove 84. In this forward state, the sub rubber 43 is located above the sub receiving portion 44, and therefore, the sub rubber 43 acts as a resistance when locking. That is, the elasticity adjusting device is in a strong state with a large resistance when rocking.

  As shown in FIG. 12, a female cam groove 84 in the slider 74 is provided at the base end of the operating cam 75 so that the slider 74 is not rotated in the direction of the dotted arrow in FIG. A restricting portion 86a that abuts against the opening edge is provided. The back cover 28 closes the swing member 18 from behind. Therefore, the left and right side plates of the swing member 18 are provided with relief slots 87 into which the outer cylinder 55 of the operation mechanism portion 27 is fitted.

(6) Summary As described above, since the main rubber 40 and the sub-rubber 43 are formed in a fan shape (or trapezoidal shape) when viewed from the side, an equal pressing force acts on both the rubbers 40 and 43 during locking. For this reason, it is excellent in durability, and a comfortable rocking state can be obtained by holding the degree of backward tilt and the degree of increase in resistance in an equal relationship.

  Since the main rubber 40 is fitted in the main recess 42 of the receiving member 41 so as not to be displaced, it is restricted from freely spreading and deforming. For this reason, the unit area is larger than the case of freely spreading and deforming. The amount of deformation (compression amount) per hit is small, and as a result, a high elastic force can be obtained. As a result, the function of imparting resistance to rocking is accurately exhibited while being compact.

  Further, since the stopper pin 46 is interposed between the main rubber 40 and the main pressing member 38 and the receiving member 41, the main rubber 40 remains in the main recess even when a backward pressing force is applied during pre-tensioning and locking. As a result, the main rubber 40 can be compressed into a uniform state and the durability can be improved.

  Although it is possible to provide only one main rubber 40, if the sub rubber 43 is disposed between the left and right main rubbers 40 as in the present embodiment, the main rubber 40 may be twisted even when the sub rubber 43 is in a pressurized state. There is an advantage that does not occur. It is also possible to provide a plurality of sub rubbers 43. In the case where the sub rubber 43 is provided, the main rubber 40 and the sub rubber 43 can be arranged in the front-rear direction.

(7). Other Embodiments FIG. 14A shows a second embodiment schematically showing a modification of the first embodiment. In this embodiment, the sub rubber 43 is fixed to the sub receiving portion 44, and the sub rubber 43 can be changed between a pressurized state and a non-pressurized state by moving the movable sub pressing member 90 left and right. The sub pressing member 90 may be added to the slider 74 of the first embodiment.

  In the third embodiment shown in FIGS. 14B and 14C, a rectangular parallelepiped rubber 92 is used. That is, in this embodiment, a rectangular parallelepiped rubber 92 is fitted into a box-shaped receiving member 93 attached to the base 2 from above, and a lid member 94 covering the rubber 92 is slidably fitted into the receiving member 93. A rib 94 a protruding from the lid member 94 and the side plate 18 a of the swing member 18 are connected by a laterally long pressing pin 95. The pin hole 96 in the swing member 18 is a long hole in the longitudinal direction.

  In this embodiment, when the rocking member 18 is locked, the pressing pin 95 slides through the elongated hole 96 and the lid member 94 is pushed right below by the pressing pin 95. Therefore, the rubber 92 always has a uniform compressive force from above. Receive.

(8). Others The present invention can be embodied in various ways other than the above embodiment. For example, it is needless to say that the present invention can be applied to a chair in which the seat does not rise and retract when rocking (however, when the seat rises when rocking, a part of the weight of the person acts in the direction of returning the backrest. Therefore, since the burden on the rubber is small, it can be said that it is suitable as an application target of the present invention. Needless to say, the present invention can also be applied to a chair that is not provided with the elasticity adjusting device. In the above embodiment, the rubber is pressurized via the pressing member, but it is also possible to pressurize directly with a back support device such as a swinging member.

  The recess in which the rubber is mounted on the receiving member does not need to be entirely surrounded by walls or ribs, and may have a configuration in which ribs are dotted around. In short, it suffices if a stopper means is provided to prevent the rubber from shifting. It is also possible to fix the receiving member to the swinging member. In the case of the embodiment, the main recess 43 is inclined backward with respect to the horizontal, but the main rubber 40 is prevented from moving forward by this backward inclination.

  The chair to be applied is not limited to a swivel chair, but can be applied to a non-lifting chair such as a conference chair or a fixed chair such as a theater chair.

  The present invention is embodied in the chair of the present invention and its usefulness is exhibited. Therefore, it can be used industrially.

1 Leg support (gas cylinder)
DESCRIPTION OF SYMBOLS 2 Base 3 Seat 4 Backrest 7 Seat receiving body 10 Back frame which comprises a back support device 18 Swing member which comprises a back support device 19 Main rubber 41 Receiving member 42 Main recess 43 Sub rubber 44 Sub receiving part 45 Relief part 74 Slider

Claims (1)

A base provided at an upper end of the leg; a seat disposed above the base; a back support device connected to the base so as to be tiltable rearwardly; a backrest provided on the back support device; and a rear tilt of the back support device A rubber that imparts resistance to the chair, and the rubber is sandwiched between a first member and a second member that rotate relative to each other when locking,
The rubber is fitted in a recess of the receiving member provided on either one or both of the first member and the second member so as not to be displaced,
Rocking chair.

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