JP2017079942A - Reaction force adjusting mechanism and chair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a small-sized mechanism and also realize a simple structure by restricting the number of components.SOLUTION: A reaction force adjusting mechanism includes: a sliding block 35 that receives and supports one end of a coil spring 30d, which is allowed to intervene between a main frame 1 and a synchro frame 10 swingable to the main frame 1 and is arranged along a swinging direction of the synchro frame 10, through a front spring mount 30b; a cylindrical screw member 37 that has a screw formed on an outer peripheral surface; a reaction force adjusting rotary shaft 34 that is arranged along the swinging direction of the synchro frame 10 and also in a vertical direction or in the form of leaning forward or backward, passes through the cylindrical screw member 37 in an axial direction and allows the cylindrical screw member 37 to be attached on its outer peripheral surface; and a guide member 39 that holds the sliding block 35 so as to move in the axial direction of the reaction force adjusting rotary shaft 34.SELECTED DRAWING: Figure 14A

Description

  The present invention relates to a reaction force adjusting mechanism and a chair. More specifically, the present invention relates to a mechanism for adjusting the magnitude of a reaction force of a reaction mechanism that generates a reaction force by a reaction force spring, and a chair provided with such a mechanism.

  As a conventional reaction force adjusting device, as shown in FIG. 29, a base 101, a back support body 108 supported by a first support shaft 107 on the rear side of the base 101, and a vertically swingable upper side of the base 101. And a seat support 102 whose rear part is rotatably connected to the back support 108 by a second support shaft 109 positioned behind the first support shaft 107 and the back of the base 101. A reaction force mechanism 103 that urges the support body 108 and the seat support body 102; and a reaction force adjustment mechanism 104 that changes a force applied to the seat support body 102 by the reaction force mechanism 103. A spring support 105 that is swingably supported by the base 101 so as to be always located in the support 102 and slidably supported with respect to the seat support 102, and the spring support 105 and the seat support 102. Placed horizontally between The reaction force adjusting mechanism 104 has a pair of left and right reaction force springs 106 and 106 provided, and the reaction force adjusting mechanism 104 sets the angle of opening of the pair of left and right reaction force springs 106 and 106 in both the left and right directions around the vertical axis. There is one that changes the force applied to the seat support 102 by changing the symmetry (Patent Document 1).

JP 2008-132322 A

  However, in the reaction force adjusting device disclosed in Patent Document 1, it is applied to the seat support 102 by changing the opening angle of the pair of left and right reaction force springs 106, 106 arranged in the horizontal direction in both the left and right directions. Since the force is changed, a space for accommodating the pair of left and right reaction force springs 106 and 106 is required. In addition, the pair of left and right reaction force springs 106 and 106 expand in both the left and right directions. Space to get is needed. For this reason, there is a problem that it becomes a restriction or design restriction when designing the arrangement of other members in that a sufficient space for the reaction mechanism is required.

  In the reaction force adjustment device in Patent Document 1, since the pair of left and right reaction force springs 106 and 106 are used, there is a problem that the number of parts increases and the structure becomes complicated.

  Accordingly, an object of the present invention is to provide a reaction force adjusting mechanism capable of reducing the mechanism and reducing the number of parts and simplifying the structure, and a chair provided with the reaction force adjusting mechanism. And

  In order to achieve such an object, the reaction force adjusting mechanism of the present invention is interposed between a frame that constitutes a seat and a frame that pivotally connects a backrest to the frame that constitutes the seat. An initial inclination angle of a coil spring arranged along the swinging direction of a frame that is provided at the left and right center position below the front side of the seat and that connects the backrest so as to be swingable is changed.

  The reaction force adjusting mechanism according to the present invention includes a sliding block that supports one end of the coil spring and a swinging direction of the frame that connects the backrest so as to be swingable, and the vertical direction or the front. The sliding block is provided with a through hole through which the shaft passes, and moves in the axial direction of the shaft in a state of passing through the shaft, thereby The initial inclination angle of the coil spring may be changed by moving one end of the coil spring supported and supported by the sliding block.

  The reaction force adjusting mechanism of the present invention further includes a cylindrical screw member having a screw formed on an outer peripheral surface, and a guide member that holds the sliding block so as to be movable in the axial direction of the shaft. The shaft penetrates the cylindrical screw member in the axial direction, the cylindrical screw member is attached to the outer peripheral surface of the shaft, and the outer peripheral surface of the cylindrical screw member is attached to the inner peripheral surface of the through hole of the sliding block. When the shaft rotates, the screw on the outer peripheral surface of the cylindrical screw member meshes with the screw on the inner peripheral surface of the through-hole of the sliding block, and the slide is guided by the guide member. While the rotation of the moving block is restricted, the sliding block moves in the axial direction of the shaft, thereby moving one end of the coil spring supported and supported by the sliding block. It may be to change the serial initial inclination angle.

  Therefore, according to these reaction force adjustment mechanisms, by changing the inclination angle of the coil spring, the angle between the frame and the coil spring that connects the backrest in the initial position (in other words, the initial state) in a swingable manner is increased. Therefore, the force acting in the direction to return the frame to the initial position changes, and the apparent magnitude of the reaction force of the coil spring that biases the frame is adjusted.

  In addition, for example, when adjusting the apparent magnitude of the reaction force of the coil spring by changing the initial length, a large force is required to compress the coil spring, whereas the reaction force adjustment described above is required. In the case of the mechanism, the apparent angle of the reaction force of the coil spring is adjusted without requiring a large force as in the case of compressing the coil spring, because only the inclination angle of the coil spring is changed. The

  According to these reaction force adjusting mechanisms, the shaft is arranged along the swing direction of the frame that connects the backrest so as to be swingable, and the sliding block moves in the axial direction of the shaft. Therefore, a large dimension in the left-right direction is not required as a space for accommodating the coil spring as the reaction force applying mechanism and the reaction force adjusting mechanism of the coil spring.

  In the reaction force adjusting mechanism of the present invention, both end surfaces of the cylindrical screw member in the axial direction may be in contact with inner surfaces of the opposing walls of the guide member. In this case, the axial load acting on the cylindrical screw member is received by the opposing walls of the guide member.

  In the reaction force adjusting mechanism of the present invention, the sliding block, the cylindrical screw member, and the guide member may be formed of resin. In this case, the screwing sliding as the feed screw mechanism between the sliding block and the cylindrical screw member and the contact sliding between the sliding block and the guide member become smooth.

  Further, the reaction force adjusting mechanism of the present invention is interposed between a frame that constitutes the seat and a frame that connects the backrest so that the backrest is swingable, and reacts to a frame that connects the backrest so that it can swing. Only the one coil spring may exert the force. In this case, by using only one reaction force applying mechanism, the number of parts can be suppressed and the structure can be simplified.

  Moreover, the chair of this invention is provided with the above-mentioned reaction force adjustment mechanism. In this case, a chair in which the action of the reaction force adjusting mechanism described above is achieved is realized.

  According to the reaction force adjusting mechanism of the present invention and the chair provided with this reaction force adjusting mechanism, the reaction of the coil spring that urges the frame that connects the backrest so as to be swingable by simply changing the inclination angle of the coil spring. Since the apparent magnitude of the force can be adjusted, the number of parts is suppressed, and the reaction force adjustment mechanism can be configured by a very simple and small-scale mechanism. It becomes possible to reduce labor and cost.

  According to the reaction force adjusting mechanism of the present invention and the chair provided with the reaction force adjusting mechanism, the reaction force is adjusted by changing the inclination angle of the coil spring. Compared with the mechanism for adjusting the force, the force required for the reaction force adjustment operation can be reduced, the operability can be improved, and the comfort during use can be improved. Further, since a large force (load) does not act on each member constituting the reaction force adjustment mechanism, the reaction force adjustment mechanism can be constituted by a resin molded product or the like.

  According to the reaction force adjustment mechanism of the present invention and the chair provided with this reaction force adjustment mechanism, the reaction force application mechanism and the reaction force adjustment mechanism can be configured without requiring large dimensions in the left-right direction. It is possible to improve the versatility of the reaction force adjusting mechanism by relaxing restrictions on designing the arrangement of other members and restrictions on the design.

  The reaction force adjusting mechanism of the present invention and the chair equipped with this reaction force adjusting mechanism guide the axial load acting on the cylindrical screw member when both end surfaces of the cylindrical screw member are in contact with the inner surface of the guide member. Since it can be received by the opposing walls of the member, the mechanism for preventing the shaft from coming off can be simplified.

  The reaction force adjusting mechanism of the present invention and the chair equipped with this reaction force adjusting mechanism can smoothen the sliding motion between the components when the components are made of resin. Thus, it is possible to reduce the force required for the reaction force adjustment operation, improve the operability, and improve the comfort during use.

  The reaction force adjusting mechanism of the present invention and the chair provided with this reaction force adjusting mechanism can reduce the number of parts and simplify the structure when the reaction force applying mechanism is only one coil spring. As a result, it is possible to reduce the labor and cost of the assembly work.

It is a front perspective view which shows the whole structure of the chair of embodiment. It is a disassembled perspective view which shows the whole structure of the chair of embodiment. It is a front perspective view which shows the structure of the part relevant to the reaction force adjustment mechanism of this invention. It is a back perspective view which shows the structure of the part relevant to the reaction force adjustment mechanism of this invention. FIG. 4 is a view showing a state in which a seat receiving part, a back frame attaching part cover, and a left sync frame are removed from FIG. FIG. 5 is a view showing a state in which the seat receiving part, the back frame attaching part cover, and the left synchro frame in FIG. It is a perspective view which shows the locking mechanism of embodiment. It is a center longitudinal cross-sectional view of the locking mechanism of embodiment. It is the perspective view which looked at the center longitudinal section of the locking mechanism of an embodiment from the slanting lower side. It is a perspective view of a pair of right and left synchro frames of an embodiment, and a synchro frame joint which connects these. It is a perspective view of the synchro frame of an embodiment. It is a perspective view of a synchro frame joint metal fitting of an embodiment. It is a disassembled perspective view of the main frame of embodiment. It is a figure which shows an example of embodiment of the reaction force adjustment mechanism of this invention, and is the figure seen from diagonally back. It is a figure of the state which removed the guide member of FIG. 14A. It is a figure of the state which removed the front spring mount of FIG. 14B. It is a figure of the state which removed the sliding block of FIG. 14C. It is a figure which shows the reaction force adjustment mechanism of embodiment, and is the figure seen from diagonally forward. It is the figure which decomposed | disassembled some reaction force adjustment mechanisms of embodiment. It is a figure explaining the aspect of contact | abutting with the reaction force adjustment mechanism and front spring mount of embodiment. It is a front perspective view showing a lock mechanism of an embodiment. It is a back perspective view showing the locking mechanism of an embodiment. It is a figure of the state which removed the synchro frame, the synchro frame joint metal, the synchro frame rotating shaft, the seat back support shaft, and the reaction force giving mechanism receiving shaft in FIG. It is a figure of the state which removed the synchro frame, the synchro frame joint metal, the synchro frame rotating shaft, the seat back support shaft, and the reaction force applying mechanism receiving shaft in FIG. It is a figure of the state which removed the operating lever for levers and a lever swing axis | shaft of FIG. It is the figure of the state which removed the operating lever for lock plates of FIG. 21, and a lever swing axis | shaft. It is a figure of the state (state which a lock plate exists in a lock release position) from which the lock plate slid back from the state (state in which a lock plate is in a lock position) of FIG. It is a figure of the state which removed the lock plate of FIG. It is a figure of the state which removed the lock plate of FIG. It is a figure explaining the sliding operation | movement of the lock plate in the lock mechanism of embodiment, and is a figure which shows the state which a lock plate slides ahead and exists in a locked position. It is a figure explaining the sliding operation | movement of the lock plate in the lock mechanism of embodiment, and is a figure which shows the state which a lock plate slides back and exists in a lock release position. It is a perspective view which shows the conventional reaction force adjustment apparatus.

  Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

  FIGS. 1 to 28 show an example of an embodiment of a reaction force adjusting mechanism of the present invention and a chair provided with the reaction force adjusting mechanism.

  In the present embodiment, the structure of the portion related to the present invention in the chair whose overall configuration is shown in FIG. 1 is related to the structure of the chair seat and back, as shown in FIGS. 3 to 6. A case where the reaction force adjustment mechanism is applied will be described as an example.

  In the description of the present invention, “upper” and “lower”, “front” and “rear”, and “left” and “right” are defined based on the seated person sitting on the chair (in other words, And “up” and “down”, “front” and “rear”, and “left” and “right” as viewed from the seated person).

  In the rocking chair of this embodiment, the seat 7 and the backrest 8 (only the back frame is shown) are supported by the main frame attached to the upper end of the leg 9 and swing with respect to the main frame. The backrest 8 attached to the synchro frame (which may also serve as a back support rod) has a constant repulsive force due to the reaction force imparting mechanism and the lock mechanism that can fix the tilting posture stepwise when the synchro frame is tilted backward. It is tilted backward while receiving, and is fixed at the selected backward tilt position.

  The locking mechanism is covered with the under-seat front cover 29a, the under-seat rear cover 29b, and the back frame attachment portion cover 29c so that it is not exposed to the exterior. Reference numeral 8a in the figure is a hanger for hanging clothes, and 8b is a lumbar support. Furthermore, the leg 9 in this embodiment is a so-called rotating leg provided with a caster 9c at the tip of five leg blades 9b spreading radially, for example, but may be a fixed leg in some cases.

  Here, as shown in FIGS. 3 to 9, the locking mechanism according to the present embodiment includes a main frame 1, a sync frame 10 that swingably connects a backrest 8 to the main frame 1, and a sync frame. The reaction force is applied between the end opposite to the portion where the backrest 8 is attached about the sync frame rotating shaft 4 and the front end side of the main frame 1 and applies a reaction force to the sync frame 10. A mechanism 30 and a lock mechanism 50 that can fix the tilt posture in a stepwise manner when the sync frame 10 is tilted backward are provided.

  In the present embodiment, an example is described in which the seat 7 moves backward while interlocking with the back tilt of the backrest 8 and the rear end side sinks. However, the present invention is applicable to this embodiment. However, the present invention is not particularly limited to this, and it is needless to say that the present invention can be applied to a locking mechanism in which only the backrest 8 is tilted backward.

  In the case of the present embodiment, the main frame 1 is composed of a seat receiving member support part 2 and a pedestal support part 3 as shown in FIG. It forms a structure of shape.

  The seat support member supporting component 2 includes a top plate portion 2A and left and right outer wall portions 2B formed by bending a single steel plate into a U-shaped cross section by bending by pressing.

  On the other hand, the pedestal support part 3 has a pedestal support hole 3d that penetrates the column support 9d that fits the top part (around the operation valve of the gas spring) of the pedestal 9a by press bending the steel plate. 3A of bottom plate parts, the front wall 3B which receives and supports the center part of the seat receiving member support component 2, and the rear wall 3C which arrange | positioned the engaging part 51 which inserts the lock plate 53 which comprises the locking mechanism 50 in multiple steps | paragraphs Molded integrally.

  For example, as shown in FIGS. 7 to 9, the engagement protrusion 3 e is engaged with the upper end of the front wall 3 B of the pedestal support member 3, and the front wall 3 B is engaged with the top plate portion 2 A of the seat receiving member support component 2. The holes 2f into which the engaging protrusions into which the protruding pieces 3e are inserted are provided, and the front wall 3B and the top plate 2A are integrated by fitting and welding these holes. On the other hand, the rear wall 3C and the top plate portion 2A are integrated by butt welding the rear wall 3C of the pedestal support member 3 and the rear end surface of the top plate portion 2A of the seat receiving member support component 2. .

  The column support hole 2g through which the column support 9d for holding the column 9a passes is coaxially formed with the column support hole 3d of the bottom plate portion 3A of the column support part 3 so that the column column support hole 2g is formed into a hemispherical shape by pressing. And formed on the top plate 2A. Then, as shown in FIG. 7, the column support 9d and each support hole 3d, with the column support 9d penetrating the leg column support hole 3d of the bottom plate 3A and the leg column support hole 2g of the top plate 2A, A 2 g peripheral portion is fixed by welding. Therefore, the seat receiving member support component 2 and the pedestal support component 3 are connected to each other at the center portion by the support bracket 9d, and the rigidity as the structure is ensured. Incidentally, the flange 9df provided at the lower end of the column support 9d is addressed from the back side to the bottom plate portion 3A of the columnar support component 3, so that the support for the columnar support component 3 and the main frame 1 is reinforced. Has been.

  Further, as shown in FIGS. 7 and 13, at the rear end side of the top plate portion 2 </ b> A of the seat receiving member support component 2, the maximum inclination position, that is, the backrest at which the sync frame 10 can swing is maximized. A damper 2c that restricts the tiltable position is provided. The damper 2c has a pin shape with a head having a material having an interference function, such as a hard urethane cushion, and is fixed by being fitted into a hole 2d drilled at a predetermined position of the top plate 2A. ing.

  In addition, a receiving plate 2e that supports the reaction force applying mechanism 30 is formed on the front side of the top plate portion 2A by cutting and raising. In the receiving plate 2e, the hole 2j into which the engaging protrusion 33a at the upper end of the mounting bracket 33 constituting the reaction force adjusting mechanism 32 of the reaction force applying mechanism 30 is fitted and the upper end of the reaction force adjusting rotating shaft 34 are rotatable. And a bearing hole 2k to be supported.

  The mounting bracket 33 of the reaction force adjusting mechanism 32 is fixed to the receiving plate 2e by fitting the upper end protruding projection 33a into the hole 2j of the receiving plate 2e and welding. At the same time, both side surfaces of the mounting bracket 33 are fixed to the outer wall portion 2B by being welded after arriving at the left and right outer wall portions 2B of the seat receiving member supporting component 2 from the inside. Of course, the method for fixing and connecting the members is not particularly limited to the above-described welding method and the welding location.

  Further, a long hole 19 is formed in the left and right outer wall portions 2B on the front end side of the seat receiving member support component 2 so as to be movably supported in the front-rear direction through which the seat front support shaft 5 passes. The long holes 19 are preferably punched at the same time when punching the blank from the steel plate material of the seat support member supporting component 2, but may be processed separately. Further, it is preferable that the edge of the long hole 19 is edged with a plastic cover (not shown) in order to improve the slidability of the seat front support shaft 5.

  Reference numeral 2h in the figure is a hole through which the sync frame rotating shaft 4 passes. Reference numeral 2i denotes an arrangement in which the free end (tip) side of the gas cylinder operation link 26 that is rotatably supported by the synchro frame rotating shaft 4 inside the seat receiving member support component 2 is brought out of the top plate portion 2A. It is a hole for making it. The gas cylinder operation link 26 is rotated about the sync frame rotating shaft 4 by operating an elevating lever (not shown), and the valve at the top of the gas cylinder with a lock mechanism constituting the pedestal 9a is depressed at the tip portion. It opens and closes.

  On the other hand, in the middle of the seat receiving member support component 2, as shown in FIG. 7 and the like, the sync frame 10 can be rotated by a sync frame rotating shaft 4 passing through holes 2h provided in the left and right outer wall portions 2B. It is swingably attached.

  The sync frame 10 connects the main frame 1 and the backrest 8, and the backrest 8 is attached to the rear end, while the reaction force applying mechanism 30 is provided between the mainframe 1 and the backrest 8. The force of the reaction force applying mechanism 30 is transmitted to the backrest 8 when the backrest 8 is tilted backward.

  In this embodiment, the sync frame 10 functions as a lever that supports the backrest 8 and tilts the backrest 8 with the synchro frame rotation shaft 4 as a fulcrum, and the left and right outer walls of the seat support member support component 2. Part 2B, slightly forward of the mounting position of the pedestal 9a, is slidably connected by a synchro frame rotating shaft 4 rotatably supported on the left and right outer wall parts 2B with a bearing bush 20 interposed therebetween. Yes.

  In the case of the present embodiment, the sync frame 10 is a pair of left and right flat plates having the same shape, and is connected by a sync frame joint 11 as shown in FIGS.

  The synchro frame joint 11 spans between the left and right synchro frames 10 arranged side by side and connects and integrates them, and at least the main frame at the maximum rearward tilt position of the synchro frame 10. 1 functions as a damper receiving portion that forms a stopper structure that intersects with 1.

  The shape of the sync frame 10 in a side view is determined by the positional relationship in which the three axes, that is, the sync frame rotation shaft 4, the seat rear support shaft 6, and the reaction force applying mechanism receiving shaft 31 are attached. In addition, the overall shape is gentle. In the figure, reference numeral 24 a is a hole through which the synchro frame rotating shaft 4 is passed, 24 b is a hole through which the seat rear support shaft 6 is passed, and 24 c is a hole through which the reaction force applying mechanism receiving shaft 31 is passed.

  The sync frame 10 includes an engagement protrusion 21 that fits into the recesses 22 on the left and right side edges of the rear bridge portion 14 of the sync frame joint 11. Since the engaging protrusion 21 of the synchro frame 10 is fitted with the recess 22 of the synchro frame joint 11 to prevent positioning and misalignment when the synchro frame 10 and the synchro frame joint 11 are assembled. It is sufficient that the projection is such that the sync frame joint 11 is not displaced at least along the upper surface of the sync frame 10 (a plane parallel to the sync frame rotation shaft 4). In other words, the amount of protrusion of the sync frame 10 from the upper surface of the engagement protrusion 21 is sufficient as long as the thickness of the sync frame joint 11. Therefore, the synchro frame has a smart shape in which the contour shape of the blank at the time of cutting is almost uneven. At the same time, the left and right synchro frames have the same shape.

  At this time, since the blank layout (planning plan) of the synchro frame 10 is a simple contour shape with a small unevenness, the blank can be arranged side by side with a minimum gap, so Economical (yield) is good. In addition, since the sync frame 10 has no left and right, it is possible to share parts and reduce the number of parts. Therefore, parts management becomes easy.

  The synchro frame joint 11 is also a substantially rectangular blank and has a simple contour shape with few irregularities, so that blanks can be arranged side by side with a minimum gap, so the economics of material removal (yield) ) Is good. In addition, since the left and right sides of the synchro frame 10 are eliminated, the parts can be shared and the number of parts can be reduced.

  Moreover, after punching the blank, the four through holes 23a through which screws for attaching the backrest 8 are passed, the two slits 18 for penetrating and supporting the lock plate 53, and the lock plate 53 are connected to the main frame 1 A through hole 25a through which a set screw (not shown) for rotatably attaching the vicinity of the center of the lock plate operating lever 54 that moves forward and backward (locked / unlocked) toward the engaging portion 51 of the rear wall 3C is inserted; , A guide groove 56 that holds the hook-like hook portion 54c at the tip of the lock plate operation lever 54 in the U-shaped groove portion 12 so as to be slidably held, and for the lock plate One end of a torsion coil spring 57 for transmitting the movement of the operation lever 54 to the lock plate 53 is punched with a long hole 27 for introducing the end into the U-shaped groove 12. It can be formed at a time by the gas.

  The nuts 23 and 25 are welded to the opposite surface of the through hole 25a through which the set screw for supporting the four through holes 23a for attaching the backrest 8 and the lock plate operating lever 54 is passed. The corresponding screws can be screwed. Of course, a female screw may be cut in the synchro frame joint 11 itself, but it is preferable to use a nut in order to secure a sufficient screw length and to omit the threading.

  In the blank development, the synchro frame joint 11 has a U-shaped (hat-shaped) groove portion 12 which is folded back four times in the front-rear direction of a substantially rectangular blank, and also has a front portion serving as a damper receiving portion. The bridge portion 13 and the rear bridge portion 14 also serving as a backrest frame attachment portion for attaching the backrest 8 to the rear are integrally formed. Since the U-shaped groove portion 12 is provided, the strength is higher than that of a simple flat joint, and a receiving portion that supports both ends by penetrating the lock plate 53 inside the U-shaped groove portion 12 can be configured.

  The U-shaped groove portion 12 has, for example, a bottom portion 15 that is a flat surface, a front wall portion 16 that is perpendicular to the bottom portion 15, and a rear wall portion 17, and the front wall 3 </ b> B and the rear wall 3 </ b> C have substantially the same height. A slit 18 to be drilled is provided. Then, the lock plate 53 is accommodated and held in parallel with the bottom portion 15 so as to pass through the slits 18 of the front wall 3B and the rear wall 3C and straddle the front wall 3B and the rear wall 3C. The lock plate 53 is slidable in the front-rear direction by swinging in the front-rear direction. In the present embodiment, the bottom portion 15 is a plane substantially parallel to the front bridge portion 13, but is not particularly limited thereto, and does not hinder the function of the lock plate operation lever 54 as a support member. The surface may be inclined or curved in the range.

  The rear bridge portion 14 has a width wider than that of the U-shaped groove portion 12, protrudes outward from the U-shaped groove portion 12, and is arranged in parallel so as to sandwich the U-shaped groove portion 12. It is provided to ride on top. Moreover, the recessed part 22 is each provided in the middle part in the right-and-left both sides edge part. As a result, a total of four protruding portions are formed on both sides of the rear cross-linking portion 14 in the front-rear direction with the recess 22 in between, and are provided so as to ride on the synchro frame 10. Therefore, positioning is possible by placing four protruding portions on the upper edge of the synchro frame 10 and fitting the engaging protrusions 21 on the synchro frame 10 side into the recesses 22.

  A back frame attaching portion 8c at the bottom of the backrest 8 is placed on the back bridge portion 14 and fixed using four screws. That is, the rear bridge portion 14 functions as a back frame attachment portion.

  The front bridge portion 13 is welded to the left and right sync frames 10 so as to straddle between the left and right sync frames 10. The front bridging portion 13 connects the left and right synchro frames 10 to each other to form a structure, and at one end (lower end) of the synchro frame 10 that can swing between the synchro frame 10 and the damper 2c of the seat receiving member support component 2. The stopper structure for regulating the side) is configured.

  Therefore, when the sync frame 10 tilts backward about the sync frame rotation axis 4, the crossing angle between the main frame 1 and the sync frame 10 is narrowed, and the seat receiving member support component 2 of the main frame 1 and the sync frame 10 The front bridge portion 13 comes into contact. At this time, the damper 2c attached to the top plate portion 2A of the seat receiving member support component 2 and the front bridge portion 13 come into contact with each other, thereby restricting the synchro frame 10 from being tilted further and backrest at that time. 8 and the load acting on the seat 7 are supported.

  The sync frame 10 and the sync frame joint 11 configured as described above are in a state in which the sync frame 10 is kept at a constant interval by placing the sync frame 10 on both sides of the U-shaped groove 12 in the width direction. Therefore, in this state, the synchro frame joint 11 and the synchro frame 10 can be integrated by welding to form a single structure in which the left and right synchro frames 10 are linked.

  According to the locking mechanism of the present embodiment configured as described above, the mechanical structure is entirely composed of a bent product of a steel plate and is inexpensive because no die-cast product is required. In addition, since it is a bent product of a steel plate, it can be made compact and lightweight.

  On the other hand, in the present embodiment, the seat 7 is supported above the main frame 1 and the sync frame 10, and the back frame mounting portion 8 c of the backrest 8 is directly mounted on the sync frame 10. 7 constitutes a synchro king mechanism that performs a backward tilting operation in synchronism.

  The seat 7 includes, for example, a seat receiving member (outer shell) 7a that is supported and attached so as to be tiltable with respect to the main frame 1, a seat plate (not shown) serving as a core, a cushion placed thereon, And an upholstery covering the cushion. The seat 7 is supported at the front by a seat front support shaft 5 that passes through a long hole 19 formed at the front end portion of the main frame 1, and is coupled to the sync frame 10 so that the seat rear support shaft 6 can swing rearward. Supported. As a result, the back of the seat 7 moves up and down as the synchro frame 10 swings and swings while the front slides back and forth, and the backrest 8 and the seat 7 perform a locking operation in conjunction with each other. A hook 7 b is provided at the rear end portion of the seat receiving member 7 a and is hooked on the seat rear support shaft 6 attached to the sync frame 10 to be supported by the sync frame 10 and swing in conjunction with the sync frame 10. It is fixed so that it can move freely. The sync frame 10 and the seat rear support shaft 6 and the sync frame 10 and the reaction force applying mechanism receiving shaft 31 of the reaction force applying mechanism 30 are fixed by welding.

  Further, the locking mechanism of the present embodiment is provided with a reaction force applying mechanism 30 that is interposed between the main frame 1 and the sync frame 10 and biases the sync frame 10 toward the initial position.

  The reaction force applying mechanism 30 functions to apply a repulsive force / reaction force to the backrest 8 and the tilt of the seat 7 to return to the initial position by urging the front end portion of the sync frame 10 backward. The initial position is a state in which the front end portion of the sync frame 10 is pushed back to the full, and the backrest 8 attached to the rear bridge portion 14 provided at the rear end portion of the sync frame 10 is pulled up to the full position. For example, FIGS. 3 to 6 show a state in the initial position.

  The reaction force imparting mechanism 30 of the present embodiment straddles between the front spring mount 30b and the rear spring mount 30c, which are guided by the sliding shaft 30a and can change the distance between them, and both the spring mounts 30b and 30c. And a compression coil spring 30d that is fitted and interposed. In FIG. 3, the compression coil spring 30d is indicated by phantom lines, and in other drawings, the compression coil spring 30d and the sliding shaft 30a are not shown.

  The front spring mount 30b and the rear spring mount 30c have shaft portions that are inserted into the compression coil springs 30d, and when the compression coil springs 30d are compressed by the backward tilting operation of the synchro frame 10, together with the sliding shafts 30a. The compression coil spring 30d is held so as not to buckle.

  The front spring mount 30b is in contact with the sliding block 35 of the reaction force adjusting mechanism 32, and the seat receiving member support component 2 (main frame) via the reaction force adjusting mechanism 32 fixed to the front position of the main frame 1. 1) supported.

  Further, the rear spring mount 30c is supported by a reaction force applying mechanism receiving shaft 31 attached to the front end portion of the sync frame 10, and the reaction force applying mechanism 30 and the sync frame 10 can swing through the rear spring mount 30c. Connected to

  The reaction force applying mechanism receiving shaft 31 is disposed below the main frame 1, and both left and right end portions are respectively inserted into the front end portions of the left and right sync frames 10 and fixed to the left and right sync frames 10. Attached.

  The rotary slide mechanism including the seat front support shaft 5 and the seat rear support shaft 6 constitute a locking mechanism in which the backward tilting operation of the sync frame 10 and the backward tilting operation of the seat 7 are performed in conjunction with each other.

  Specifically, first, in a state where no load is applied to the seat 7 or the backrest 8, as shown in FIGS. 3 to 6, the front end portion of the synchro frame 10 is moved by the reaction force applying mechanism 30. The backrest 8 is biased rearward at a position below the rotary shaft 4 and the backrest 8 is in a position that supports the back of the seated person in the natural posture (that is, the initial position).

  When the seated person leans on the backrest 8, the backrest 8 and the synchro frame 10 tilt backward about the synchro frame rotation shaft 4 while the reaction force applying mechanism 30 is pushed and shrunk. At the same time, the rear portion of the seat receiving member 7a is pulled backward and obliquely downward by the connection via the seat rear support shaft 6, and the seat front support shaft 5 moves rearward in the long holes 19 and 19 to thereby move the seat receiving member 7a. Tilts while sliding backwards.

  On the other hand, when the seated person who has been leaning on the backrest 8 raises his / her upper body, the reaction force applying mechanism 30, specifically, the reaction force applying mechanism 30 exerts a reaction force that extends, thereby synchronizing the frame 10. At the same time, the rear end of the seat receiving member 7a is pushed up and the seat receiving member 7a slides forward.

  When the sync frame 10 is tilted backward and the seat receiving member 7a is tilted while sliding backward, the seat front support shaft 5 moves in the long holes 19 and 19 of the main frame 1 to move the long holes 19 and 19 to each other. By abutting on the rear peripheral surface, the rearward tilt of the synchro frame 10 and the sliding and tilting of the seat receiving member 7a are restricted.

  The reaction force adjusting mechanism 32 adjusts the force acting in the direction in which the compression coil spring 30d returns the synchro frame 10 to the initial position by changing the inclination angle at the initial position of the compression coil spring 30d constituting the reaction force applying mechanism 30. To do.

  The reaction force adjustment mechanism 32 is fixed to the seat receiving member support component 2 of the main frame 1 by a mounting bracket 33 that holds the guide member 39.

  The mounting bracket 33 has a U-shaped side wall portion that holds the guide member 39 so as to sandwich the guide member 39 from both sides, and a bottom portion that supports the bottom portion of the guide member 39, and holds the guide member 39 while holding the guide member 39. 39 is fixed to the main frame 1.

  Specifically, the projection formed on the upper end of the mounting bracket 33 is suspended from the main frame 1 by being welded in a state of being inserted into a slit formed on a receiving plate 2e formed integrally with the main frame 1. The mounting bracket 33 is fixed to the main frame 1 so as to be lowered, the guide member 39 held by the mounting bracket 33 is extended, and the reaction force adjusting mechanism 32 is fixed to the main frame 1. Attached.

  Further, a reaction force adjustment rotating shaft 34 of the reaction force adjusting mechanism 32 is fitted into a through hole formed in the central portion of the receiving plate 2e and is rotatably supported.

  The reaction force adjusting mechanism 32 of the present embodiment is a frame that connects the backrest 8 so as to be swingable with respect to the main frame 1 that constitutes the seat 7 and the frame that constitutes the seat 7 (main frame 1). A frame (synchronous frame 10) is provided along the frame (synchronous frame 10), which is interposed between the frame 10 and the synchro frame 10 and is provided at a central position on the lower side of the front side of the seat 7 so that the backrest 8 is swingably connected. The inclination angle at the initial position of the coil spring 30d arranged in this manner is changed.

  Further, the reaction force adjusting mechanism 32 of the present embodiment has a specific configuration in which the sliding block 35 that supports and supports one end of the coil spring 30d via the front spring mount 30b and the backrest 8 are swingably connected. And a reaction force adjusting rotating shaft 34 as a shaft that is disposed in a tilted manner along the swing direction of the frame (synchronized frame 10), and the sliding block 35 penetrates the reaction force adjusting rotating shaft 34. The reaction force adjusting rotary shaft 34 is moved in the axial direction with the through-hole 36 to be passed therethrough, and is thereby supported and supported by the sliding block 35 via the front spring mount 30b. One end of the coil spring 30d is moved to change the inclination angle at the initial position of the coil spring 30d.

  The reaction force adjustment mechanism 32 of the present embodiment has a specific configuration, and can further move the cylindrical screw member 37 having a screw formed on the outer peripheral surface and the sliding block 35 in the axial direction of the reaction force adjustment rotating shaft 34. And a reaction force adjusting rotary shaft 34 that penetrates the cylindrical screw member 37 in the axial direction, and the cylindrical screw member 37 is attached to the outer peripheral surface of the reaction force adjusting rotary shaft 34. In addition, a screw that meshes with the screw on the outer peripheral surface of the cylindrical screw member 37 is formed on the inner peripheral surface of the through hole 36 of the sliding block 35, and the screw on the outer peripheral surface of the cylindrical screw member 37 rotates when the reaction force adjusting rotary shaft 34 rotates. Meshes with the screw on the inner peripheral surface of the through hole 36 of the sliding block 35 and the sliding block 35 is moved in the axial direction of the reaction force adjusting rotary shaft 34 while the rotation of the sliding block 35 is restricted by the guide member 39. This , Previous via a spring mount 30b to move the one end of the coil spring 30d that is supported received by sliding block 35 so that changing the angle of inclination in the initial position of the coil spring 30d.

  An axial key 40 is integrally formed on the outer peripheral surface of the reaction force adjusting rotary shaft 34 as a rail-like convex portion. In the present embodiment, a pair of keys 40 are formed on the outer peripheral surface of the reaction force adjusting rotary shaft 34 at positions facing each other in the radial direction.

  Further, a through-hole into which the reaction force adjusting rotary shaft 34 is fitted is provided at the center axis position of the cylindrical screw member 37, and the key 40 is located at a corresponding position / interval of the key 40 on the inner peripheral surface of the through-hole. An axial keyway 41 to be fitted is formed.

  The reaction force adjusting rotary shaft 34 and the cylindrical screw member 37 are coupled to each other such that the key 40 and the key groove 41 are engaged and engaged with each other so that the shaft cannot rotate.

  In addition, the coupling | bonding aspect of the reaction force adjustment rotating shaft 34 and the cylindrical screw member 37 is not limited to the aspect which the key 40 and the keyway 41 fit and engage, It couple | bonds by another method. You may do it.

  The cylindrical screw member 37 has a length in which both end faces in the axial direction (upper end face and lower end face) abut against the inner surfaces of the opposing upper wall 39b and lower wall 39c of the guide member 39 (that is, the upper wall 39b). And the same length as the distance between the lower surface of the lower wall 39c and the upper surface of the lower wall 39c). A male screw is formed on the outer peripheral surface of the cylindrical screw member 37. In each drawing shown as an example, the cylindrical screw member 37 is illustrated as a simple cylindrical member, and a screw thread is not illustrated.

  The reaction force adjusting rotary shaft 34 is provided with a seat receiving portion 44 that is engaged with the lower surface of the lower wall 39c of the guide member 39 at a position near the lower end, and an attachment portion 34a that fits with the slit 38a of the handle 38. Provided at the lower end. A handle 38 is attached to the lower end of the reaction force adjusting rotary shaft 34.

  On the surface of the front spring mount 30b facing the sliding block 35, a recess 43 having a vertical cross-sectional shape along the vertical plane is an arc shape (that is, engraved in a bowl shape).

  Further, a semi-cylindrical convex portion 42 having a shaft arranged in a direction orthogonal to the axis of the screw hole 36 on the surface of the sliding block 35 facing the front spring mount 30b (in other words, protruding in a bowl shape). Is provided.

  That is, the concave portion 43 of the front spring mount 30b and the convex portion 42 of the sliding block 35 are both formed so as to arrange the central axis in a direction orthogonal to the vertical plane, and can swing with each other along the vertical plane. Abut.

  When the convex portion 42 of the sliding block 35 is fitted into the concave portion 43 of the front spring mount 30b, the force applied to the compression coil spring 30d is received by the sliding block 35 and the reaction force including the compression coil spring 30d. One end (the front end in the example shown in the figure) of the applying mechanism 30 is supported so as to be swingable.

  On the other hand, the rear spring mount 30c has an engagement hook 30e that is attached to the front end of the synchro frame 10 and engages the shaft, and a receiving portion 30f that is pressed against the shaft, and is attached to the reaction force applying mechanism receiving shaft 31. It is attached.

  The force applied to the compression coil spring 30d is received by the reaction force applying mechanism receiving shaft 31, and the other end (the rear end in the example shown in the figure) of the reaction force applying mechanism 30 including the compression coil spring 30d can swing. It is supported by.

  The guide member 39 prevents one of the sliding blocks 35 connected to the reaction force adjusting rotating shaft 34 via the cylindrical screw member 37 from rotating about the axis of the reaction force adjusting rotating shaft 34. This is for guiding the movement in the direction (specifically, the axial direction of the reaction force adjusting rotary shaft 34).

  In this embodiment, the guide member 39 is formed as a box having an open rear surface (that is, a surface facing the reaction force adjusting rotating shaft 34), and is configured to hold the sliding block 35. .

  Specifically, the guide member 39 is in contact with the front surface of the sliding block 35 and receives the force applied from the reaction force applying mechanism 30 via the sliding block 35 and the cylindrical screw member 37. The upper wall 39b and the lower wall 39c that receive the axial load acting on the cylindrical screw member 37 by contacting the upper end surface and the lower end surface of the sliding block 35 respectively, and the left surface and the right surface of the sliding block 35 are in contact with each other. The sliding block 35 has a pair of left and right side walls 39d and 39d that prevent the sliding block 35 from rotating about the axis of the reaction force adjusting rotary shaft 34.

  A pair of left and right mounting portions 39a ′ for preventing the deformation by fixing the guide member 39 to the mounting bracket 33 and reinforcing the left and right side walls 39d, 39d from the left and right ends of the front wall 39a of the guide member 39. , 39a ′ are integrally formed.

  Through holes are formed in the upper wall 39b and the lower wall 39c of the guide member 39 facing each other, and the reaction force adjusting rotary shaft 34 passes through the guide member 39 through the through holes.

  A plurality of barbs in the axial direction of the reaction force adjusting rotary shaft 34 (that is, the direction in which the sliding block 35 slides) is provided on the inner surface of the guide member 39, and the sliding block 35 can move smoothly in the axial direction. Thus, the structure reduces the friction.

  At least the sliding block 35, the cylindrical screw member 37, and the guide member 39 are preferably formed of resin. For example, by forming the resin with a small friction coefficient such as polyacetal and exhibiting good slidability, the sliding block 35 and the cylindrical screw member 37 can be screwed together as a feed screw mechanism or the sliding block 35. And the guide member 39 are smoothly abutted and slid, and the force required to operate the reaction force adjusting mechanism 32 (specifically, the force to turn the handle 38) is reduced.

  A female screw that engages with a male screw on the outer peripheral surface of the cylindrical screw member 37 is formed on the inner peripheral surface of the screw hole 36 of the sliding block 35, and a feed screw mechanism is constituted by these screws, and these screws mesh with each other. Thus, the sliding block 35 and the cylindrical screw member 37 are connected.

  In addition, although the screw formed in the sliding block 35 or the cylindrical screw member 37 generates a large axial load, it is preferably a trapezoidal screw, but is not limited to a trapezoidal screw.

  According to the above-described configuration, when the handle 38 is rotated and the cylindrical screw member 37 rotates together with the reaction force adjusting rotating shaft 34, the sliding block 35 held by the guide member 39 is moved to the axis of the reaction force adjusting rotating shaft 34. The shaft moves linearly in the direction of the axis while being prevented from rotating around the center.

  As the slide block 35 moves, the position of the front spring mount 30b supported by the slide block 35 moves.

  At this time, the sliding block 35 moves in a straight line while being restrained by the reaction force adjusting rotary shaft 34 and the guide member 39, so that the sliding block 35, the synchro frame rotating shaft 4, and the axis of the reaction force applying mechanism receiving shaft 31 are aligned. The positional relationship between changes.

  Accordingly, when viewed from the side, the reaction force applying mechanism receiving shaft 31 (the point of action of the compression coil spring 30d of the reaction force applying mechanism 30 with respect to the synchro frame 10) from the recess 43 of the front spring mount 30b that swingably contacts the sliding block 35 is provided. ) And the direction from the axis of the synchro frame rotating shaft 4 to the axis of the reaction force applying mechanism receiving shaft 31 change, in other words, the compression coil spring 30d. Accordingly, the force (that is, effective reaction force) acting in the direction in which the compression coil spring 30d returns the synchro frame 10 to the initial position is changed, that is, the reaction force applying mechanism 30 is changed. Thus, the reaction force exerted on the sync frame 10 is adjusted. Therefore, the repulsive force when falling on the backrest 8 can be adjusted to suit the seated person's preference.

  The angle formed by the direction from the axial center of the synchro frame rotating shaft 4 to the axial center of the reaction force applying mechanism receiving shaft 31 and the direction from the recess 43 toward the axial center of the reaction force applying mechanism receiving shaft 31 in a side view. In other words, changing the size of the angle formed between the direction toward the synchro frame rotating shaft 4 and the direction toward the recess 43 with the axis of the reaction force applying mechanism receiving shaft 31 as a vertex means that the sync frame 10 This means that the expansion / contraction direction of the compression coil spring 30d with respect to the direction is changed, that is, the direction of the reaction force acting on the synchro frame 10 is changed. The size of the directional component acting on changes.

  According to the reaction force adjusting mechanism configured as described above and the chair provided with this reaction force adjusting mechanism, the backrest 8 at the initial position (in other words, the initial state) is changed by changing the inclination angle of the compression coil spring 30d. Since the size of the angle formed between the synchro frame 10 as a swingably connected frame and the compression coil spring 30d can be changed, the force acting in the direction to return the synchro frame 10 to the initial position changes, and the synchro frame 10 is The apparent magnitude of the reaction force of the biasing compression coil spring 30d is adjusted. For this reason, since the apparent magnitude of the reaction force of the compression coil spring 30d that biases the synchro frame 10 can be adjusted simply by changing the inclination angle of the compression coil spring 30d, the number of parts is suppressed. The reaction force adjustment mechanism can be configured by a very simple and small-scale mechanism, and as a result, the labor and cost of the assembly work can be reduced.

  In addition, for example, when adjusting the apparent magnitude of the reaction force of the coil spring by changing the initial length, a large force is required to compress the coil spring, whereas the reaction force adjustment described above is required. In the case of the mechanism, since only the inclination angle of the compression coil spring 30d is changed, the apparent magnitude of the reaction force of the coil spring is not required without requiring a large force when the coil spring is compressed. Adjusted. For this reason, it is possible to reduce the force required for the reaction force adjustment operation, improve the operability, and improve the comfort during use. Further, since a large force (load) does not act on each member constituting the reaction force adjusting mechanism (for example, the handle 38 and the reaction force adjusting rotating shaft 34, the sliding block 35, the cylindrical screw member 37, the guide member 39, etc.). The reaction force adjusting mechanism can be configured by a resin molded product or the like.

  According to the reaction force adjusting mechanism configured as described above and the chair provided with this reaction force adjusting mechanism, the synchro frame 10 serving as a frame for connecting the backrest 8 so as to be swingable is provided along the swinging direction. Since the reaction force adjusting rotary shaft 34 is arranged so that the sliding block 35 moves in the axial direction of the reaction force adjusting rotary shaft 34, the compression coil spring 30d constituting the reaction force applying mechanism 30 and the compression A large dimension in the left-right direction is not required as a space for accommodating the reaction force adjusting mechanism 32 of the coil spring 30d. For this reason, it becomes possible to ease the restrictions at the time of designing the arrangement of other members and the restrictions on the design, thereby improving the versatility as the reaction force adjusting mechanism.

  Here, in the present embodiment, only the reaction force applying mechanism 30 is provided as a mechanism for exerting a reaction force on the synchro frame 10 that swings with respect to the main frame 1. That is, as a chair locking mechanism, in addition to the mechanism corresponding to the reaction force applying mechanism 30 in the present embodiment, which is disposed in the lower front side of the seat 7 (in other words, in front of the pedestal 9a of the leg 9), Two which are disposed so as to be interposed between the main frame 1 and the sync frame 10 at the rear lower side or rear side (in other words, the rear side of the pedestal 9a of the leg 9) and exhibit a reaction force to the sync frame 10. In contrast to the conventional manner in which a fluid spring is further provided as a reaction force application mechanism for the eyes, in the present embodiment, only one reaction force application mechanism 30 is provided at the center of the left and right of the front side of the seat 7. The second reaction force application mechanism is not provided.

  In the conventional locking mechanism, a fluid spring having a lock mechanism is used as the second reaction force application mechanism described above, and the lock function of the second reaction force application mechanism is used. Thus, fixing of the tilting operation of the backrest 8 and release of the fixing are controlled.

  On the other hand, in the present embodiment, only the reaction force applying mechanism 30 that does not include the lock mechanism is provided, and the lock mechanism 50 controls the fixing / unlocking of the tilting operation of the backrest 8.

  The lock mechanism 50 disables or permits the swing of the sync frame 10 that can swing with respect to the main frame 1 about the sync frame rotation shaft 4, thereby allowing the backrest to be attached to the sync frame 10. The control of the tilting operation of 8 and the release of the fixing are controlled.

  The lock mechanism 50 of the present embodiment is provided on the main frame 1 as the first member and the synchro frame 10 as the second member and the first member (main frame 1) which are connected to each other so as to be swingable. And the second member (synchronous frame 10) so as to be slidable back and forth in the direction toward the engaged member (leg column supporting component 3). And a locking plate 53 as an engaging member that is supported and provided, and the engaged member (leg post supporting component 3) is arranged along the swinging direction of the first and second members. A plurality of engaging portions 51 provided and a guide portion 52 provided along the swinging direction of the first and second members, and the engaging member (lock plate 53) slides back and forth. Responsible by The short locking piece 53a that is inserted into or disengaged from the engaging portion 51 of the member (leg post supporting component 3) and the guide portion 52 of the engaged member (leg post supporting component 3) are always provided. And a long locking piece 53b for maintaining the inserted state.

  An engaging portion 51 and a guide portion 52 are provided on the rear wall 3 </ b> C of the pedestal support member 3 constituting the main frame 1. In the present embodiment, the rear wall 3C of the pedestal support member 3 is constituted by a plate-like member, and the engaging portion 51 and the guide portion 52 are provided as through holes formed in the plate-like member.

  The plate-like member constituting the rear wall 3 </ b> C of the pedestal support member 3 is formed to be curved in an arc shape centered on the synchro frame rotation shaft 4 in a side view. Thereby, when the sync frame 10 swings around the sync frame rotation shaft 4, the distance between the rear surface of the rear wall 3C and each part of the sync frame 10 is kept constant.

  The engaging portion 51 of the rear wall 3C of the pedestal support member 3 is formed as a horizontally long (that is, left and right) rectangular through hole.

  A plurality of the engaging portions 51 are arranged in a direction in which the sync frame 10 swings (that is, in the vertical direction) with a space between each other, and are orthogonal to the direction in which the sync frame 10 swings. A plurality of them are arranged side by side (in the left-right direction) at intervals.

  In other words, the engaging portion 51 has a plurality of steps in the direction in which the synchro frame 10 swings (that is, the vertical direction), and a plurality in the direction orthogonal to the direction in which the synchro frame 10 swings (that is, the left-right direction). Are provided.

  The number of the engaging portions 51 arranged in the vertical direction (that is, the number of steps as the engaging portion group) and the number arranged in the left-right direction (that is, the number of rows as the engaging portion group) The interval is not limited to a specific number or value, but is preferably a tilting range preferable as a mechanism for tilting and fixing the backrest, the number of positions where the tilting operation can be fixed, and / or the pitch of the tilt angle at the time of fixing, etc. Is appropriately set to an appropriate number or value.

  In the present embodiment, as an example, five engaging portions 51 are arranged in the vertical direction and four in the left-right direction, that is, arranged in five stages and four rows.

  The guide portion 52 of the rear wall 3C of the pedestal support member 3 is formed as a vertically long rectangular through hole along the direction in which the sync frame 10 swings (that is, the vertical direction).

  The guide portion 52 is disposed between the left two-row engaging portion 51 group and the right two-row engaging portion 51 group among the four rows in total in the left-right direction, and thus the rear wall of the pedestal support member 3. It is provided at the center position in the left-right direction of 3C.

  The lock plate 53 as an engaging member is engaged with the engaged member (the pedestal support part 3) to fix and release the swing of the synchro frame 10 and the tilt of the backrest 8 as well. And control.

  The material of the lock plate 53 is preferably a metal so that the load applied to the backrest 8 can be received and the tilt of the backrest 8 can be fixed, but the required strength can be exhibited. Any resin or other material may be used.

  The lock plate 53 is formed as a plate-like member having a short locking piece 53a and a long locking piece 53b at the front end portion thereof, and the synchro frame 10 side in a state where the plate surface is horizontal (that is, in the left-right direction). It is arranged.

  The long locking piece 53b of the lock plate 53 is provided to be longer than the short locking piece 53a, in other words, to protrude further forward than the short locking piece 53a.

  The lock plate 53 constitutes the U-shaped groove portion 12 of the synchro frame joint 11 fixedly attached to the synchro frame 10, and each of the front wall portion 16 and the rear wall portion 17 formed to face each other in the front-rear direction. In addition, it is slidably supported in a state of being inserted into the left and right slits 18 and 18 formed at positions facing each other in the front-rear direction.

  With the above-described structure, the lock plate 53 is supported by the synchro frame joint 11 fixed and attached to the synchro frame 10 in such a manner that the lock plate 53 can be slid in the front-rear direction and the movement in the vertical direction is limited.

  In the lock plate 53, the short locking piece 53a at the front end portion is inserted into or disengaged from the engaging portion 51 by the sliding operation in the front-rear direction, and the long locking piece 53b at the front end portion is guided by the guide portion. Is inserted into 52 (in other words, inserted).

  In other words, in the present embodiment, the lock plate 53 has two engagement portions 51 on the left side corresponding to one stage of the engagement portion 51 group provided on the rear wall 3C of the pedestal support member 3 as an example. 51 and the right two engaging portions 51, 51 are provided with a short locking piece 53 a at a position corresponding to each of the right engaging portions 51, 51, and a guide provided at a central position in the left-right direction of the rear wall 3 C of the pedestal support 3. A long locking piece 53 b is provided at a position corresponding to the portion 52. That is, the lock plate 53 is provided with the two short locking pieces 53a and 53a on the left side, the central long locking piece 53b, and the two right short locking pieces 53a and 53a side by side in the left-right direction.

  Then, when the lock plate 53 slides forward and the short locking piece 53a at the front end portion is fitted into the engagement portion 51 (the position of the lock plate 53 at this time is referred to as “lock position”; 23 and 27), the lock plate 53 extends over the main frame 1 and the synchro frame joint 11 fixedly attached to the synchro frame 10, and the synchro frame 10 swings. The tilting of the backrest 8 is fixed by being limited via 53.

  On the other hand, when the lock plate 53 slides rearward and the short locking piece 53a at the front end portion is disengaged from the engaging portion 51 (the position of the lock plate 53 at this time is referred to as a “lock release position”; 28), the restriction of the swing of the synchro frame 10 is released, and the backrest 8 can be tilted.

  Here, when the lock plate 53 slides in the front-rear direction between the lock position and the unlock position, the lock plate 53 may be located on either the lock position or the unlock position. The state in which the long locking piece 53b of 53 is inserted into the guide portion 52 is always maintained.

  That is, when the lock plate 53 slides forward and is in the locked position, the short locking pieces 53a are simultaneously inserted into the corresponding engaging portions 51, and the long locking pieces 53b are inserted into the guide portions 52. Plugged in.

  Further, when the lock plate 53 slides rearward and is in the unlocked position, each short locking piece 53a is completely disengaged from the corresponding engaging portion 51, while the long locking piece 53b is moved to the guide portion 52. It remains plugged in.

  And, regardless of the sliding movement of the lock plate 53 in the front-rear direction, in other words, regardless of the position of the lock plate 53 in the front-rear direction, the long locking piece 53 b is always inserted into the guide part 52, so the upper end of the guide part 52 The range of movement of the lock plate 53 relative to the rear wall 3C of the pedestal support member 3 constituting the main frame 1 is limited from the position where it contacts the lower end to the position where it contacts the lower end.

  Therefore, the movable range of the lock plate 53 is adjusted by adjusting the length of the guide portion 52 in the direction in which the sync frame 10 swings (that is, the vertical direction), and thereby the sync frame 10 with respect to the main frame 1 is adjusted. The swing range of the backrest 8 is adjusted, and thus the tilt range of the backrest 8 is adjusted.

  Note that the limitation of the swing range of the synchro frame 10 due to the contact between the guide portion 52 and the long locking piece 53b of the lock plate 53 is that the sync frame 10 can be swung up with the upper end of the guide portion 52. Either of the above-described restriction and the restriction of the downward swing range of the synchro frame 10 by being brought into contact with the lower end of the guide portion 52 may be performed. Both the limitation and the limitation of the downward swing range may be performed.

  Specifically, in the present embodiment, the reaction force applying mechanism 30 urges the front end portion of the synchro frame 10 toward the back, and the backrest 8 supports the seated person's natural posture back (that is, the initial position). The upper end position of the guide portion 52 is adjusted so that the long locking piece 53b of the lock plate 53 in the position) is in contact with the upper end of the guide portion 52, and the upward swing range of the sync frame 10 is limited. .

  The sliding movement of the lock plate 53 in the front-rear direction is performed by operating the lock plate operation lever 54.

  The lock plate operating lever 54 has a handle portion 54a and a shaft portion 54b. The lock plate operating lever 54 is disposed below the bottom portion 15 of the U-shaped groove portion of the synchro frame joint 11 fixedly attached to the synchro frame 10. It is attached to the joint 11 so as to be swingable.

  The lock plate operating lever 54 is vertically disposed through the bottom portion 15 of the U-shaped groove portion of the synchro frame joint 11 so as to be axially rotatable, and at the connecting portion between the handle portion 54a and the shaft portion 54b. It is attached to the synchro frame joint 11 so as to be swingable by a lever swing shaft 55 fixed to the operation lever 54.

  It protrudes upward at the tip of the shaft portion 54b of the lock plate operating lever 54 (that is, the end opposite to the connecting portion between the handle portion 54a to which the lever swing shaft 55 is fixed and the shaft portion 54b). A hook-shaped hook portion 54c is formed.

  A guide groove 56 through which the hook portion 54c of the lock plate operating lever 54 passes is formed in the front-rear direction at the bottom 15 of the U-shaped groove portion of the synchro frame joint 11.

  The hook-shaped hooking portion 54c penetrates the guide groove 56 from the bottom to the top, and the bent portion of the hook-shaped hooking portion 54c is hooked on the peripheral edge portion of the guide groove 56, whereby the tip of the shaft portion 54b. The side is slidably hung on the bottom 15 of the U-shaped groove of the synchro frame joint 11.

  In this embodiment, at the position near the right end of the bottom 15 of the U-shaped groove of the synchro frame joint 11, the lever swing shaft 55 penetrates the bottom 15 in the vertical direction, and the handle portion starts from the position of the lever swing shaft 55. The lock plate operation lever 54 is disposed so that the protrusion 54a protrudes to the right and the shaft portion 54b extends to the left. The hook portion 54c at the tip of the shaft portion 54b of the lock plate operation lever 54 is provided. A guide groove 56 in the front-rear direction is formed at a position corresponding to the left end of the bottom portion 15 of the U-shaped groove portion of the synchro frame joint 11.

  The opening range as the guide groove 56 in the front / rear direction restricts the stroke length of the movement of the hooking portion 54c in the front / rear direction, and consequently, the swing range in the front / rear direction of the lock plate operating lever 54 is restricted. The

  Further, the lock plate 53 and the lock plate operation lever 54 are slid back and forth between the lock position and the lock release position when the lock plate operation lever 54 is swung back and forth. To be connected.

  Specifically, in this embodiment, the lock plate 53 and the lock plate operation are provided by the torsion coil spring 57 disposed so as to be interposed between the lock plate 53 and the shaft portion 54 b of the lock plate operation lever 54. The lever 54 is connected, and the operation of the lock plate operation lever 54 is transmitted to the lock plate 53.

  A long hole 27 in the front-rear direction for allowing the torsion coil spring 57 to pass therethrough is formed in the bottom 15 of the U-shaped groove of the synchro frame joint 11.

  The torsion coil spring 57 has one end connected to the lock plate 53 and the other end connected to the lock plate operating lever 54, and is pushed forward from the position where the handle 54a of the lock plate operating lever 54 is pushed backward. It is arranged so that the direction of the urging force applied to the lock plate 53 through the thought point is reversed while swinging to the specified position.

  Specifically, in this embodiment, when the handle portion 54a of the lock plate operating lever 54 is pushed backward, the shaft portion 54b swings forward and the lock plate 53 moves to the lock position. The plate 53 is elastically biased forward by a torsion coil spring 57.

  At this time, although the handle portion 54a of the lock plate operating lever 54 is pushed backward, the position of the short locking piece 53a of the lock plate 53 and the position of the engaging portion 51 do not match, so the short locking piece 53a. Is unable to fit into the engaging portion 51, the force is accumulated in the torsion coil spring 57, and the biasing force of the torsion coil spring 57 when the short locking piece 53a can be fitted into the engaging portion 51. As a result, the lock plate 53 is slid and the short locking pieces 53 a are fitted into the engaging portions 51.

  On the other hand, when the handle portion 54a of the lock plate operating lever 54 is pushed forward, the shaft portion 54b swings rearward and the lock plate 53 moves to the unlocking position. In this state, the lock plate 53 is twisted by the torsion coil spring 57. Is elastically biased backward.

  Note that the mechanism of the connection between the lock plate 53 and the lock plate operation lever 54 is as long as the lock plate 53 slides in conjunction with the swing operation of the lock plate operation lever 54. Not limited. In addition, although it is preferable to be restrained moderately at the locked position and unlocked position by being elastically biased as in the above-described mechanism, it is essential in the present invention that the biasing is moderately performed at each position. is not.

  According to the lock mechanism 50 configured as described above and the chair provided with the lock mechanism 50, the short locking piece 53a is fitted into the engagement portion 51 as the lock plate 53 as the engagement member slides. When the main frame 1 and the synchro frame 10 are restricted from being allowed to swing, the long locking piece 53b is always inserted into the guide portion 52. Therefore, by a set of engaging members (lock plate 53) and engaged members (leg post supporting parts 3), it is possible to restrict and release the swinging motion between the two members, In addition, the swing range of the two members can be regulated by the formation range of the guide portion 52. For this reason, it is possible to reduce the size of the mechanism, reduce the number of parts, and simplify the structure as compared with the case of providing a mechanism having these functions separately.

  According to the lock mechanism 50 configured as described above and the chair provided with the lock mechanism 50, the long locking piece 53b of the lock plate 53 as an engaging member on the synchro frame 10 side is also a guide on the main frame 1 side. Since the state of being always inserted into the portion 52 is maintained and the long locking piece 53b is always guided by the guide portion 52, the swinging of these members when the main frame 1 and the synchro frame 10 swing relative to each other is performed. It is possible to ensure straightness of operation. For this reason, the pair of engaging members (lock plate 53) and the engaged member (leg post supporting part 3) can restrict and release the swinging motion between the two members, and In addition to being able to regulate the swing range between the two members, it is possible to ensure straightness of the swing motion between the two members.

  Although the above-described embodiment is an example of a preferred embodiment for carrying out the present invention, the embodiment of the present invention is not limited to the above-described embodiment, and the present invention is not limited to the scope of the present invention. The invention can be variously modified.

  For example, in the above-described embodiment, the present invention is applied to the seat and back structure as shown in FIGS. 3 to 6 of the chair whose overall configuration is shown in FIG. The specific shapes and modes of the constituent members such as the main frame 1, the seat receiving member 7a, and the sync frame 10 to which the invention can be applied are not limited to those in the above-described embodiment, and the use and design of the chair. Is selected as appropriate. Specifically, for example, in the above-described embodiment, the locking mechanism is configured such that the backrest 8 and the seat 7 perform a locking operation in conjunction with each other. However, in the present invention, only the backrest 8 performs the locking operation. It is also possible to apply to a locking mechanism or to a locking mechanism in which only the seat 7 performs a locking operation.

  Further, in the above-described embodiment, the main frame 1 is configured by combining the seat receiving member support component 2 and the pedestal support component 3 formed by bending a steel plate by press working, but the configuration mode of the main frame 1 is the above-described configuration mode. It is not limited to the aspect in embodiment. The main frame 1 is for supporting the seat receiving member 7a and the sync frame 10 to be mounted on the pedestal 9a of the leg 9 of the chair, and supports each component such as the seat receiving member 7a and the sync frame 10. However, it is not limited to a specific structure or shape, and may be a general die-cast integrally formed product.

  In the above-described embodiment, the guide member 39 of the reaction force adjusting mechanism 32 is configured to have the front wall 39a, the upper wall 39b, the lower wall 39c, and the pair of side walls 39d and 39d. The configuration aspect of the force adjustment mechanism 32 is not limited to the aspect in the above-described embodiment, and is unidirectional (specifically, while preventing axial rotation around the axial center of the reaction force adjustment rotary shaft 34 of the slide block 35). Specifically, any mode may be used as long as it can guide movement in the axial direction of the reaction force adjusting rotary shaft 34. Specifically, for example, a pair of left and right locking pieces projecting left and right from the left and right surfaces of the sliding block 35 are formed, and the pair of left and right locking pieces are slidably fitted as guide members. A linear engagement groove or engagement hole is formed on the main frame 1 side, and the axial rotation of the sliding block 35 is prevented by the sliding engagement between the locking piece and the engagement groove / engagement hole. In addition, it may be configured to move in one direction. That is, the guide member 39 may be formed as an engagement groove or an engagement hole with which the locking piece formed on the slide block 35 is slidably engaged.

  Further, in the above-described embodiment, the reaction force adjustment rotating shaft 34 of the reaction force adjusting mechanism 32 is arranged in a backward inclined posture. However, the arrangement (posture) of the reaction force adjusting rotating shaft 34 is the above-described embodiment. It is not limited to the form in the embodiment, and the reaction force adjusting rotary shaft 34 may be arranged in a posture along the vertical direction or may be arranged in a forward leaning posture.

  Further, in the above-described embodiment, sliding is performed by meshing the screw on the outer peripheral surface of the cylindrical screw member 37 attached to the reaction force adjusting rotary shaft 34 with the screw on the inner peripheral surface of the through hole 36 of the sliding block 35. Although the block 35 is moved in the axial direction of the reaction force adjusting rotating shaft 34, the mode of the mechanism for moving the sliding block 35 is not limited to the mode in the above-described embodiment, and the synchro frame Any mechanism may be used as long as the sliding block 35 can be moved so that the positional relationship between the rotating shaft 4 and the axis of the reaction force applying mechanism receiving shaft 31 changes.

  In the above-described embodiment, the engaging portion 51 and the guide portion 52 of the locking mechanism 50 are formed as through holes. However, the engaging portion 51 and the guide portion 52 of the locking mechanism 50 are formed as through holes. The engaging portion 51 and the guide portion 52 may be formed as a recess or groove into which the short locking piece 53a or the long locking piece 53b of the lock plate 53 is inserted. In addition, the engaging portion 51 may be formed as a recess or a groove, and the guide portion 52 may be formed as a through hole, or may be formed in the opposite manner.

  In the above-described embodiment, the engagement portion 51 and the guide portion 52 of the lock mechanism 50 are provided on the main frame 1 side and the lock plate 53 is provided on the synchro frame 10 side. The arrangement of the engagement portion and the guide portion and the lock plate that constitute the lock mechanism is not limited to the embodiment in the above-described embodiment, and the engagement portion 51 and the guide portion 52 that constitute the lock mechanism 50 are synchronized frames. The lock plate 53 may be disposed on the main frame 1 side while being provided on the 10 side.

  In the above-described embodiment, the engaging portion 51 and the guide portion 52 of the lock mechanism 50 are formed directly on the rear wall 3C of the pedestal support member 3 constituting the main frame 1, but the lock mechanism 50 is The aspect of installation of the engaging part and the guide part to be configured is not limited to the aspect in the above-described embodiment, but is a separate part (engaged part) in which the engaging part 51 and the guide part 52 constituting the lock mechanism 50 are formed. The combination member) may be attached to the main frame 1 (the seat receiving member support part 2, the pedestal support part 3). However, the engaging portion 51 and the guide portion 52 are formed directly on the members and parts constituting the main frame 1 as in the above-described embodiment, thereby reducing the number of parts and simplifying the structure. As a result, it is possible to reduce the labor of assembling work.

DESCRIPTION OF SYMBOLS 1 Main frame 2 Seat receiving member support component 2e Support plate 3 Leg pillar support component 3C Rear wall 4 Synchro-frame rotation shaft 5 Seat front support shaft 6 Seat rear support shaft 7 Seat 7a Seat support member 8 Backrest 9 Leg 9a Leg column 10 Synchro frame 11 Synchro frame joint 12 U-shaped groove portion 15 Bottom portion 16 Front wall portion 17 Rear wall portion 18 Slit 19 Long hole 30 Reaction force applying mechanism 30a Sliding shaft 30b Front spring mount 30c Rear spring mount 30d Compression coil spring 30e Engagement Hook 30f Receiving portion 31 Reaction force applying mechanism receiving shaft 32 Reaction force adjusting mechanism 33 Mounting bracket 34 Reaction force adjusting rotating shaft 34a Mounting portion 35 Sliding block 36 Screw hole 37 Cylindrical screw member 38 Handle 38a Slit 39 Guide member 39a Front wall 39a 'Mounting portion 39b Upper wall 39c Lower wall 39d Side wall 40 Key 41 Key groove 42 Convex portion 43 Concave portion 44 Seat rest Part

Claims (7)

  One is provided at the left and right central position below the front side of the seat while being interposed between a frame constituting the seat and a frame that pivotally connects the backrest to the frame constituting the seat. A reaction force adjusting mechanism characterized by changing an initial inclination angle of a coil spring arranged along a swinging direction of a frame for connecting the swingable swingably.   A sliding block that supports one end of the coil spring, and a shaft that is arranged along the swinging direction of the frame that connects the backrest so as to be swingable, and is vertically or forwardly or backwardly tilted. And the sliding block has a through hole through which the shaft passes, and moves in the axial direction of the shaft in a state of passing through the shaft, whereby the coil supported and supported by the sliding block The reaction force adjusting mechanism according to claim 1, wherein one end of a spring is moved to change the initial inclination angle of the coil spring.   A cylindrical screw member having a screw formed on an outer peripheral surface; and a guide member that holds the sliding block so as to be movable in the axial direction of the shaft, wherein the shaft axially holds the cylindrical screw member. The cylindrical screw member is attached to the outer peripheral surface of the shaft, and a screw is formed on the inner peripheral surface of the through hole of the sliding block to mesh with the screw on the outer peripheral surface of the cylindrical screw member. When the shaft rotates, the screw on the outer peripheral surface of the cylindrical screw member meshes with the screw on the inner peripheral surface of the through hole of the sliding block, and the sliding of the sliding block is restricted by the guide member. The block moves in the axial direction of the shaft, thereby moving one end of the coil spring supported and supported by the sliding block to change the initial inclination angle of the coil spring. A reaction force adjustment mechanism according to claim 2, wherein.   The reaction force adjusting mechanism according to claim 3, wherein both end surfaces of the cylindrical screw member in the axial direction are in contact with inner surfaces of opposing walls of the guide member.   The reaction force adjusting mechanism according to claim 3, wherein the sliding block, the cylindrical screw member, and the guide member are made of resin.   The one coil spring that is interposed between the frame constituting the seat and the frame that pivotably connects the backrest and that exerts a reaction force to the frame that pivotally connects the backrest. The reaction force adjusting mechanism according to claim 1, wherein the reaction force adjusting mechanism is only.   A chair comprising the reaction force adjusting mechanism according to any one of claims 1 to 6.