JP2016093473A - Chair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily attach/detach front member with respect to a back frame and non-detachably attach it thereto in a backrest including the back frame and a front frame.SOLUTION: A backrest 4 includes a back frame 9 rearward-tiltably attached to a base 2, and a front member 8 mounted on a front surface of the back frame 9, where a flexible sheet material 10 is stretched across the front member 8. The front member 8 comprises an upper member 27b and a lower member 27a that are mutually bendably connected. After the upper member 27b is fitted to the back frame 9, when the lower member 27a is rotationally turned, the flexible sheet material 10 is retained in a strained state. The lower member 27a is retained by a presser member 12 so as not to rotationally return. The upper member 27b is easily attached/detached with respect to the back frame 9 and, when the presser member 12 is removed, the front member 27 can be easily attached/detached.SELECTED DRAWING: Figure 10

Description

  The present invention relates to a chair mainly characterized by the structure of the backrest.

  The backrest of the chair has various structures, but in the case of an office chair, it is generally divided roughly into a cushion type and a mesh type. In the cushion type, a resin inner back shell (back plate) is placed on the front of the back frame as a strength member, and the cushion is stretched on the front of the inner back shell. Mesh material is stretched on the back frame.

  In the mesh type, as one method of attaching the mesh material to the back frame, a tape-like edge member is fixed to the periphery of the flexible sheet material by sewing or the like, and this edge member is attached to the outer periphery of the frame material. It is performed to fit in the formed groove (long groove).

  However, in the configuration in which the edge member is fitted to the outer periphery of the frame material in this way, the flexible sheet material can be easily fitted in the groove about the half circumference, but as the flexible sheet material is attached, the flexible sheet Since the force to stretch the material against the elasticity becomes strong, the flexible sheet material has to be forcibly stretched in order to fit the last part, which makes it very difficult to install the flexible sheet material. It was troublesome.

  Therefore, the applicant of the present invention in Patent Document 1 attached a part of the outer periphery of the flexible sheet material (mesh material) to the second edge member having a rigid structure by rotating, and first, the outer periphery of the flexible sheet material. The first edge member fixed to the portion excluding the second edge member is attached to the frame material, and then the second edge member is rotated to a predetermined posture so that the flexible sheet material is tensioned. Disclosed is a chair that can be held open.

JP2013-244253A

  According to Patent Document 1, since the flexible sheet material is in a slack state when the second edge member is rotated to the surface side of the flexible sheet material, the first edge member to the frame material is used. The second edge member can be rotated with a light force using the lever principle. For this reason, attachment of a flexible sheet material can be performed easily. Moreover, since it is possible to easily apply a strong tension to the flexible sheet material, the quality of the chair can be improved.

  In the embodiment of Patent Document 1, the first edge member and the second edge member are attached to the back frame by an engaging means such as an engaging claw. When this engaging means is employed, the attachment is easy. However, for example, it may be troublesome to remove the edge member when replacing the flexible sheet material. Similarly, even in a cushion type backrest, when the inner shell is attached to the back frame by the engaging means, the removal may be troublesome.

  Although the edge member and the inner shell can be said to be a front member, the present invention mainly aims to provide an improvement related to attachment / detachment of the front member.

  On the other hand, a rocking chair is often provided with a lock device that switches the backrest between a free state in which the backrest can be freely tilted and a locked state in which the backrest cannot be tilted. In the case of the rocking chair provided in the case, the backrest is held in a locked state by applying the lock body to some part of the back frame, but depending on the structure of the back frame, it is difficult to secure the part to which the lock body is applied. Or the design may become troublesome.

  Another object of the present invention is to improve the locking device.

  The present invention includes the structures of the claims. Among these, the chair according to the invention of claim 1 is configured such that the backrest includes a back frame as a strength member and a front member disposed in front of the back frame, and at least a part of the front member is backed by a pressing member. It is held so that it cannot be detached from the frame.

  According to a second aspect of the present invention, in the first aspect, the pressing member presses a part of the front member from the front, and a portion of the front member excluding a portion pressed and held by the pressing member is engaged. It is held by the means so as not to be detached from the back frame.

  Here, the “portion held by the pressing member” does not mean the portion where the pressing member hits, but the portion where the pressing function by the pressing member is exerted. Accordingly, there may be a case where the vicinity of the portion where the pressing member is in contact is included.

  According to a third aspect of the present invention, in the first or second aspect, the lower portion of the front member is held by the pressing member in a non-detachable manner on the back frame, and all or most of the pressing member is below the seat surface. Has been placed.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the front member has a frame-like shape that opens in the front-rear direction, and the flexible sheet material is disposed on the front member from the front to the rear. The pressing member is fixed to the back frame with a screw, and is attached to the lower member of the front member via the flexible sheet material. A resin-made cushioning material is provided.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the back frame is attached to the base so as to be able to tilt backward, and the pressing member is fixed to the back frame. Further, the lock body operated by lever operation is arranged so as to be switchable between a lock posture for preventing the forward movement of the pressing member and a free posture for allowing the forward movement of the pressing member.

  According to the present invention, since at least a part of the front member is held by the pressing member so as not to be detached from the back frame, the front member can be easily attached to and detached from the back frame when the pressing member is not attached. On the other hand, in the state of use as a chair, the front member can be held attached to the back frame. Therefore, it is possible to easily attach / remove and replace the front member without impairing the function as a chair.

  Although it is possible to hold the front member in a state in which the front member is not detached from the back frame only by the pressing function of the pressing member, in this case, the pressing member may be enlarged and installation of the pressing member may be troublesome.

  On the other hand, if the structure of Claim 2 is employ | adopted, the front member will hold | maintain the part hold | maintained by the engagement means like an engaging claw, an engagement hole, or an engaging claw, for example to the front frame so that it cannot move away forward. By configuring the member to be held so as not to be separated forward by the pressing function of the member, the entire front member can be held from the back frame so as not to be detached simply by pressing a part of the front member with the pressing member. And since the engaging means should just be made the structure which fits and removes simply by moving a front member to an up-down direction, for example, attachment / detachment of a front member can be performed very easily.

  If the structure of Claim 3 is employ | adopted, since a pressing member does not touch a human eye (or it is hard to touch), the appearance is good.

  If the structure of Claim 4 is employ | adopted, even if it is a case where a pressing member is made from metal, there exists an advantage which can suppress the abrasion of a flexible sheet material.

  If the structure of Claim 5 is employ | adopted, since the pressing member for pressing down a front member can be utilized for the stopper of a locking device, the freedom degree of the design of a back frame can be improved. In this case, it is preferable to dispose the pressing member in the right and left middle part of the chair, since it is possible to prevent a torsional force from acting on the back frame when the seated person leans against the backrest in the locked state.

(A) is a perspective view which shows the external appearance of the chair which concerns on 1st Embodiment, (B) is a perspective view in the state which abbreviate | omitted the flexible sheet material and the seat cushion. (A) is a perspective view which shows the framework of a backrest, (B) is a side view of a chair. (A) is the isolation | separation perspective view of the main member of a chair, (B) is the isolation | separation perspective view of a back part and a pressing member, (C) is the perspective view which looked at the pressing member from the downward direction. It is a separation perspective view of a back frame and a flexible sheet material, (A) is a figure in the state where the bent part was made into a use posture, and (B) is a figure in the state where the bent part was rotated to the near side. (A) is a separated perspective view of a back frame and a flexible sheet material, (B) is a partial perspective view of a back frame. It is a figure which shows a flexible sheet material, (A) is the perspective view seen from the back side, (B) is the perspective view in the state which removed the bending part. It is a rear view of a flexible sheet material. (A) is a separated side view of the flexible sheet material and the back frame, (B) is a perspective view of the flexible sheet material in a state where the bent portion is rotated. (A) is a cross-sectional view of the backrest as viewed from the IXA-IXA viewing direction of FIG. 7, and (B) is a flat cross-sectional view of the backrest as viewed from the IXB-IXB viewing direction of FIG. It is a vertical side view of the center part of the lower part of the backrest. (A) is the perspective view which looked at the back frame from back, (B) is the partial perspective view of the back frame in the state where the upper cover was removed, (B) is the perspective view of the upper cover. It is a separation perspective view of the main member of a chair. (A) is a perspective view of the base in the locked state, and (B) is a perspective view of the base in the free state. (A) is the isolation | separation perspective view which looked at the base from the bottom, (B) is the isolation | separation perspective view which shows the relationship between a lever and a lock body. (A) is the isolation | separation perspective view which shows the operation structure of a lock body, (B) is a perspective view of the principal part in a locked state. It is a figure which shows 2nd Embodiment, (A) is a perspective view of the whole, (B) is a perspective view which shows the relationship between a pressing member and a lower member. (A) (B) is the isolation | separation perspective view of the principal part. (A) is a longitudinal side view of the main part, and (B) is an exploded perspective view of the pressing member and the back frame.

  Next, an embodiment of the present invention will be described with reference to the drawings. 1 to 15 show the first embodiment, and FIGS. 16 to 18 show the second embodiment. In the present application, front / rear and left / right words are used to specify a direction, but these words are based on a state where a person who normally sits on a chair faces. The front view is a state seen from the direction facing the person sitting on the chair.

(1). Outline of Chair according to First Embodiment First, an outline will be described based on FIGS. The chair of this embodiment is a swivel chair widely used for office work, and the chair includes a leg device 1 having a leg column as a gas cylinder, a base 2 supported by the leg device 1, and a base 2. A seat 3 disposed above and a backrest 4 on which a seated person can rest. The base 2 is made of sheet metal and has a box-like shape opened upward as shown in FIG.

  As can be understood from FIG. 1, the seat 3 has a structure in which a seat cushion 6 is stretched on the upper surface of a resin seat inner shell 5, and the seat inner shell 5 is rearward so that its rear portion rotates downward. A hinge portion 5a is formed at the site. That is, a portion of the seat inner shell 5 in front of the hinge portion 5a is slidably attached to the base 2 in the front and rear direction, and a seat outer shell 7 shown in FIG. Is attached from below.

  As clearly shown in FIG. 4, the backrest 4 includes a frame-shaped front member 8 that opens forward and backward, and a back frame 9 that supports the frame from behind, and the front member 8 has flexibility such as mesh material. A sheet material 10 is stretched. The back frame 9 is a strength member that retains strength as a chair, and a front member 8 is attached to the strength member. The body pressure of the seated person is first applied to the flexible sheet material 10 and supported by the back frame 9.

  The front member 8 can also be called a seat frame, an inner frame, or a front frame, and the back frame 9 can also be called an outer frame or a rear frame.

  For example, as shown in FIG. 4, the front member 8 and the back frame 9 are respectively formed on upper and lower side members 8 a and 9 a, upper members 8 b and 9 b connected to the upper ends thereof, and lower ends of the left and right side members 8 a and 9 a, respectively. The lower members 8c and 9c are connected to each other, and have a trapezoidal (substantially rectangular) shape that is slightly narrowed when viewed from the front. Both the front member 8 and the back frame 9 employ resin molded products, but it is also possible to employ aluminum die-cast products or sheet metal processed products.

  The lower member 9c of the back frame 9 is integrally formed with a pair of left and right arm portions 11 extending toward the front, and left and right horizontally long pins (not shown) inserted through the front ends of the left and right arm portions 11 A portion of the seat inner shell 5 that is slightly in front of the hinge portion 5a is fixed to a slider that is fitted in the longitudinal longitudinal elongated hole formed in FIG. The back frame 9 is guided by the base 2 so that the arm portion 11 moves forward while tilting backward. Details of the locking mechanism will be described later.

  The rear end of the seat inner shell 5 is connected to the lower member 9 c of the back frame 9. Accordingly, when the backrest 4 is tilted backward, the seat 3 moves forward and the rear portion thereof is bent downward. The back tilt of the backrest 4 and the forward movement of the seat 3 are performed against the spring built in the base 2. A number of reinforcing ribs are formed on the lower member 9 c and the arm portion 11 of the back frame 9.

(2) Details of the backrest Next, details of the backrest 4 will be described with reference to FIGS. Each of the members 9a to 9c of the back frame 9 basically has a channel structure (groove-shaped structure) that opens forward, and the front member 8 is disposed so as to close the groove of the back frame 9. ing.

  Specifically, as shown in FIG. 9, the upper member 9b and the side member 9a of the back frame 9 form a rearward convex mountain shape, and as shown in FIG. 10, the lower member of the back frame 9 9c has a substantially U-shaped cross-sectional shape. The lower members 8c and 9c of the back frame 9 have a larger width (vertical width) than the other members, because a large load is applied.

  As shown in FIGS. 3 and 10, a left and right laterally long metal pressing member 12 is fixed to the lower member 9 c of the back frame 9 with four screws (not shown). A screw insertion hole of the pressing member 12 is indicated by reference numeral 12a in FIGS. In FIG. 3, the female screw hole provided in the back frame 9 is indicated by reference numeral 12b. Although the figure shows a state of fastening with four screws, either one of the upper and lower holes is used as a positioning hole, and this is inserted into a positioning boss provided on the arm portion 11 of the back frame 9 to thereby hold down the presser. It is preferred to position member 12 accurately.

  The pressing member 12 has a function of pressing the lower member 8c of the front member 8 from the near side and a function of a stopper for holding the backrest 4 in a locked state. As shown in FIGS. 3B, 3C, and 10, the left and right ends of the pressing member 12 are provided with protruding pieces 14 that contact the lower member 8c of the front member 8 from the front and above. Accordingly, the front member 8 is held so as not to move upward. As shown in FIG. 10, the function of locking the rocking chair of the backrest 4 is achieved by coming into contact with the lock body 33 from the back. This point will be described after the explanation of the backrest 4 is finished.

  For example, as can be understood from FIG. 5, each member of the front member 8 basically has a plate-like structure, and is provided with a center protrusion 13 that is thick and protrudes downward only at the left and right middle part of the upper member 8b. ing. Further, as shown in FIGS. 7, 9B, and 10, an edge member 15 such as a resin sheet is fixed to the periphery of the flexible sheet material 10 by means such as sewing, and the edge member 15 Is wound from the outside of the outer periphery of the front member 8 to the rear side and overlaps the back surface of the front member 8. Therefore, at the position of the lower member 8c, the flexible sheet material 10 is bent downward from the front and is wound back.

  As shown in FIGS. 11 (A) and 11 (B), the rear surface of the upper member 9b in the back frame 9 is a stepped portion 16 that is bent toward the front side and the lower side. In addition, a holder portion 17 to which a hanger or the like can be attached is integrally formed. When a hanger or the like is not attached, the holder portion 17 is covered with an upper cover 18 from behind and below.

  As shown in FIG. 9A, the center protrusion 13 of the front member 8 penetrates the step 16 from above. For this reason, the stepped portion 16 has a positioning hole 19 into which the center protrusion 13 is fitted. For this reason, the upper member 8b of the front member 8 is held by the upper member 9b of the back frame 9 so that it cannot be displaced forward and backward.

  Further, the upper cover 18 is provided with a claw 20 that fits into the center protrusion 13 of the front member 8 from behind. Therefore, the front member 8 is held by the upper cover 18 so as not to be displaced upward. The center protrusion 13 can also be referred to as a positioning protrusion, and may be provided not only in the left and right middle part but also in other parts. The number can also be set arbitrarily.

  For example, as shown in FIG. 7, the edge member 15 is fitted into a stopper protrusion 21 that protrudes from the back surface of the front member 8. Therefore, the edge member 15 is formed with a group of engagement holes 22 that fit into the stopper protrusions 21.

  Note that the edge member 15 does not have to be in the form of a sheet, and for example, a metal wire can be used. Alternatively, various methods such as fixing the peripheral edge of the flexible sheet material 10 to the front member 8 with a tacker can be adopted as a fixing means for the flexible sheet material 10. When stopping with a tacker, the flexible sheet material 10 may be pressed directly or may be fixed via a pressing plate.

  As a means for attaching the front member 8 to the back frame 9, in this embodiment, as shown in FIGS. 5, 6, 9 (B), etc., a downward hook-like locking claw 23 is provided on the side member 8a of the front member 8. On the other hand, the side member 9 a of the back frame 9 is provided with a catch portion 24 that opens up and down, and the engaging claw 23 is fitted into the catch portion 24. Since the catch portion 24 is formed so as to fill the groove of the side member 9a, it also serves as a reinforcing rib for the side member 9a.

  Among the side members 8a of the front member 8, a narrow positioning rib 23 'is projected rearwardly at a portion between the engaging claws 23 adjacent to each other vertically, while the left and right side members of the back frame 9 9a is formed with a positioning groove 24 'into which the positioning rib 23' is sandwiched. The stopper projection 21 is disposed between the engaging claw 23 and the positioning rib 23 '. Needless to say, the edge member 15 is formed so as not to hit the engaging claw 23 or the positioning rib 23 ′ (the engaging claw 23 or the positioning rib 23 ′ is formed from a hole provided in the edge member 15. It may be exposed.)

  As shown in FIG. 9B, the side member 9a of the back frame 9 has a V shape that widens toward the front, so that when the side member 8a of the front member 8 is fitted, the engaging claw 23 It is automatically guided to the back of the groove. Accordingly, when the side member 8 a of the front member 8 is overlapped with the side member 9 a of the back frame 9 and then shifted downward, the engaging claw 23 is smoothly drawn into the catch portion 24. For this reason, the attachment of the front member 8 can be performed easily and accurately with one touch.

  As clearly shown in FIG. 8 (A), the back frame 9 and the front member 8 are bent in a protruding shape in a front view so that the height around the waist of the seated person is closest to the front. Thus, a lumbar support portion is formed on the flexible sheet material 10 to support the seated person's lower back (particularly around the third lumbar vertebra) from behind. Although the lumbar support portion is formed on the flexible sheet material 10, for convenience, the forward projecting portions of the front member 8 and the back frame 9 are also called lumbar support portions and are denoted by reference numerals 25 and 26.

  The front member 8 and the back frame 9 are both curved in a forward concave shape in plan view with the upper members 8b and 9b and the lower members 8c and 9c. For this reason, the flexible sheet material 10 is also curved in a concave shape facing forward in plan view over the entire height.

  For example, as shown in FIGS. 6 to 8, the front member 8 is divided vertically at a portion slightly above the apex of the lumbar support portion 25, and the entire lower member 8 c and the lower end portions of the left and right side members 8 a are separated. The lower member 27a is described in the claims. Accordingly, the portion above the lower member 27a becomes the upper member 27b. The front member 8 includes a side member 8a, an upper member 8b, and a lower member 8c, and also includes an upper member 27b and a lower member 27a.

  On the left and right ends of the lower member 27 a, bearing claws 28 that open forward are projected upward. On the lower ends of the left and right side members 8 a of the upper member 27 b, A shaft 30 is provided, and a bearing claw 28 is fitted into the support shaft 30 from behind. Therefore, the pivot point (or connecting portion) of the lower member 27 a is located slightly above the lumbar support portion 25.

  As shown in FIG. 6 (A), the rear surface of the bearing claw 28 has a semicircular shape in side view, while the side member 9a of the back frame 9 has a bearing claw as shown in FIG. A recess 31 into which 28 enters is formed, so that the bearing pawl 28 is held so as not to be detached from the support shaft 302. Further, the bearing pawl 28 can be rotated around the support shaft 30 inside the recess 31.

(3) Summary of the backrest The flexible sheet material 10 is attached to the front member 8 by fitting the edge member 15 as described above, but it is flexible when the lower member 27a is bent. Since the flexible sheet material 10 can be loosened, it is very easy to attach the flexible sheet material 10 to the front member 8 (the flexible sheet material 10 is held in a stretched state by manpower or a jig. Even if not, it can be attached to the front member 8).

  The front member 8 is attached to the back frame 9 in a posture in which the lower member 27a of the front member 8 is rotated (bended) toward the front, first the upper member 27b is attached to the back frame 9, and then The procedure is performed by rotating the member 27a downward to return it to a predetermined posture.

  Since the flexible sheet material 10 is loose when the lower member 27a is rotated forward, the upper member 27a can be easily and easily attached to the back frame 9 without being pulled by the flexible sheet material 10. Can be installed accurately. Then, after attaching the upper member 27b of the front member 8 to the back frame 9, when the lower member 27a is turned back to the reference posture to be used as a chair, the flexible sheet material 10 is stretched to pinch the seated person. It can be supported accurately. The rotating operation of the lower member 27a can be easily performed with a light force using the lever principle.

  After the lower member 27a is rotated and overlaid on the back frame 9, the pressing member 12 is fixed to the lower member 9c of the back frame 9 with screws. Then, the lower member 27a is held in a state in which it cannot rotate to the front side, and the front member 8 is held so as not to move upward as a whole. As can be understood from FIG. 1 (B), the pressing member 12 is hidden under the seat 2 and cannot be visually recognized. Therefore, the provision of the pressing member 12 does not deteriorate the aesthetics.

  The pressing member 12 is attached with the seat 3 removed. Therefore, when assembling the chair, the backrest 4 is first assembled and completed, and then the procedure of attaching the pressing member 12 and attaching the seat 3 is performed.

  In addition, since the rotation fulcrum of the lower member 27a is located near the top of the lumbar support portion 25, when the lower member 27a is returned to the reference posture, the elastic force of the flexible sheet material 10 is increased by exceeding the so-called fulcrum. It acts to hold the lower member 27a in the reference posture. The body pressure of the seated person also acts to hold the lower member 27a in the reference posture.

  Therefore, when attaching the pressing member 12, it is not necessary to press and hold the lower member 27 by hand, but in the embodiment, the lower member 27a is attached to the lower member 27a or the lower member 9c, and the lower member 9c of the back frame 9 is attached. Engaging means (not shown) such as an engaging claw that is lightly elastically deformed and holds the overlapping state is provided. Thereby, since the lower member 27a is temporarily held in a state where it overlaps the back frame 9, there is an advantage that the work of fixing the pressing member 12 can be performed safely.

(4). Lock Device Next, a lock device that switches the backrest 4 between a free state in which the backrest 4 can be tilted backward and a lock state in which the backrest 4 cannot be tilted will be described mainly with reference to FIGS. First, the locking mechanism which is a premise of the locking device will be described. As already described, the base 2 has a box-like shape opened upward, and the form is shown in FIGS. The base 2 has a shape that is long in the front-rear direction, and a guide shaft 34 that protrudes to the left and right outside of the base 2 is provided at the rear end thereof.

  The rear portion of the base 2 is located between the left and right arm portions 11 in the back frame 9, and a guide slot 34 ′ (see FIG. 10) that fits in the guide shaft 34 is formed on the inner surface of the arm portion 11 in the back frame 9. Forming. The guide slot is long in the front-rear direction, and in a side view, the guide slot is inclined like a bow so that the height increases toward the rear. Therefore, when the rocking chair is used, the backrest 4 is lowered as a whole while tilting backward, and the arm portion 11 moves forward. As the arm portion 11 moves forward, a large rocking angle can be obtained even if the amount of retreat of the upper portion of the backrest 4 is not so large.

  As shown in FIG. 12, a horizontally long slide shaft 35 is inserted between the front ends of the left and right arm portions 11 in the back frame 9, and a rear spring receiver 36 is connected to the slide shaft 35. Although illustration is omitted, the rear spring receiver 36 is attached to a portion of the seat inner shell 5 that is closer to the front side than the hinge portion 5a (see FIG. 1B).

  12 and 13, the base 2 has left and right upper flanges 2a. The upper flange 2a is held by a holding part provided on the seat inner shell 5 via a slider (both not shown). For this reason, the seat 3 is mounted on the base 2 so as to be slidable back and forth. When the backrest 4 tilts backward, the slide shaft 35 and the seat 3 move forward together, and the forward movement is elastically supported by a spring (compression coil spring) 37 built in the base 2. That is, the locking is performed against the spring 37. A front spring receiver 38 is provided at the front end of the base 2.

  As can be understood from FIG. 14 (see also FIG. 10), a reinforcing bracket 39 is fixed to the lower surface of the base 2 by welding, and the bush 40 into which the leg strut (gas spring) is fitted is formed between the base 2 and the reinforcing bracket 39. And is held in a vertical posture. The reinforcing bracket 39 is provided with a rearward projecting portion 39a that overlaps the lower surface of the base 2, and the bearing member 41 is screwed to the portion of the base 2 where the rearward projecting portion 39a overlaps with a screw 42 (see FIG. 15B). It is fixed.

  In FIG. 14B and FIG. 15, the bearing member 41 is displayed so as to overlap the reinforcing member 39, but actually, the bottom plate of the base 2 is interposed between them (FIG. 10). reference). A screw 42 shown in FIG. 15B is screwed into a nut (not shown) fixed to the bottom plate of the base 2.

  The bearing member 41 is made of, for example, resin, and a downwardly-opening bearing groove 45 into which a distal end support portion 44 a of the locking rod 44 provided in the lock lever 43 is fitted is formed at the rear portion thereof, and the distal end of the locking rod 44 is formed. The support shaft portion 44a is inserted and fixed to the front end portion of the lock body 33 that is long in the front-rear direction. The lock body 33 is made of resin, but may be made of metal such as a die-cast product.

  The front end portion of the lock body 33 is fitted to the bearing member 41 from above. Accordingly, a recess 47 in which the front portion of the lock body 33 is fitted from above is formed at the rear portion of the bearing member 41, and a bearing groove 45 is formed on the side plate located on both the left and right sides of the recess 47. As shown in FIG. 10, since the front end portion of the lock body 33 is held by the recess 47 so as not to move downward, the tip support shaft portion 44a of the locking rod 44 is held so as not to move up and down.

  The locking rod 44 includes a laterally long tip support shaft portion 44 and a lever mounting portion 44b, and an intermediate portion 44c that connects them, and has a crank shape as a whole. The lever mounting portion A backward-facing lock lever 43 is attached to 44. As shown in FIG. 14A, the bottom plate of the base 2 is formed with a first relief hole 48 into which the intermediate portion 44c of the locking rod 44 is fitted. The base 2 is covered with a resin lower cover 49 from below, and the lower cover 49 is formed with a second relief hole 50 into which the lever mounting portion 44b of the locking rod 44 is fitted.

  FIG. 10 and FIG. 13 (A) show a locked state. In this state, since the pressing member 12 is located immediately behind the lock body 33, the pressing member 12 cannot move forward, and accordingly. The backrest 4 is held in a locked state where it cannot be tilted backward. In this state, the downward hook-like engagement claw 51 provided at the front end of the lock body 33 is fitted to the upper end of the front wall 52 of the recess 47 in the bearing member 41, whereby the lock body 33 is locked. Is held in.

  At the front left end of the pressing member 12, a rib piece 12 c is formed by bending downward so as to make surface contact with the rear surface of the lock body 33. The rib pieces 12c are reinforced by left and right bracket pieces 12d.

  On the other hand, when the lock lever 43 is tilted downward and rotated, the lock body 33 is tilted backward while the engaging claw 51 is deformed against elasticity, and is shifted to the free posture. As shown in FIG. 13 (B), the lock body 33 escapes downward and the advancement of the pressing member 12 is allowed. For this reason, the backrest 4 is in a free state that can be tilted backward.

  As shown in FIG. 10, when the lock body 33 is in the free posture, the lower surface of the front portion of the lock body 33 comes into contact with the stopper portion 53 provided on the bearing member 41, and the engagement claw 51 comes into contact with the front wall 50 from behind. Thus, the lock body 33 is held in a free posture.

  As can be understood from FIG. 13 (B), a lift lever 54 is attached to the bearing member 41, and a lift rod 55 is also rotatably held. That is, the lifting rod 55 has a long support shaft portion in the front-rear direction, and this support shaft portion is rotatably held by the bearing member 41 and the base 2.

  In the embodiment, the load when the seated person leans against the backrest 4 in the locked state acts on the lock body 33 as a compressive force in the longitudinal direction. Therefore, even if the lock body 33 is made of resin, it can maintain high support strength. Further, since the pressing member 12 is made of metal and is fixed to the back frame 9 with screws, there is no problem in the supporting strength of the pressing member 12. Further, since the lock body 33 is located at the right and left middle part of the chair, even if the seated person leans against the backrest 4 in the locked state, the backrest 4 is not subjected to a twisting action, and the durability of the back frame 9 is ensured. Is excellent.

(5). Second Embodiment Next, a second embodiment shown in FIGS. This embodiment is basically the same as the first embodiment, and the only difference from the first embodiment is the form of the pressing member 12. Therefore, the parts common to the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  The pressing member 12 according to the second embodiment does not include the protruding piece 14 according to the first embodiment, and can come into contact with the lower member 27 of the front member 8 over the entire length of the left and right. It is not applied directly to the lower member 27 but applied via a resin cushioning material 56.

  The cushioning material 56 is laterally long and has a form opened to the front, and the rear end has a planar view shape that is aligned with the planar view shape of the lower member 27. In addition, an upward rib 56a is provided at the rear end in order to increase the contact area with the lower member 27 as much as possible. On the other hand, a convex portion 12e is provided at the rear end of the pressing member 12 so as to fit into the buffer material 56, and as shown in FIG. 18, the engaging claw 47 provided inside the buffer material 56 is pressed. By being fitted into the engagement hole 58 of the member 12, the member 12 is held so that it cannot be removed. In addition, as shown in FIG. 17, a plurality of rearward opening slits 59 are provided in the convex portion 12 e of the pressing member 12, while the cushioning material 56 is provided with ribs (not shown) that fit into the slits 59. Prevents sticking.

  In the second embodiment, since the lower member 27 is supported by the pressing member 12 in a wide range in the left-right direction, it is possible to prevent stress from concentrating on a specific part of the lower member 27 and to improve durability. There is. Further, since the cushioning material 56 is made of resin, there is no problem of wear even when it hits the flexible sheet material 10, and the durability of the flexible sheet material 10 is also excellent.

(6). Others The present invention can be embodied in various ways. For example, the application target is not limited to a backrest using a mesh-like flexible sheet material, but can also be applied to a plate-like inner shell (back plate) with a cushion. In this case, the inner shell corresponds to the front member. For example, the inner shell can be easily attached to the back frame by configuring the inner shell with upper and lower members that can be bent.

  Further, the front member is not necessarily configured to be bent, and it is possible to engage the back frame by moving the front member downward or upward and hold the front member so that it cannot be moved up and down by the pressing member. is there. Although it is possible to hold the front member in a non-detachable manner only with the pressing member, it can be said that it is preferable to have the front member together with the engaging means.

  The back frame is not necessarily in the form of opening back and forth, and may be in the form of a cover (shell structure). Further, the back frame does not need to have a single structure, and may be composed of a plurality of members.

  The present invention is actually applicable to a chair. Therefore, it can be used industrially.

2 base 3 seat 4 backrest 8 front member 8a side member 8b upper member 8c lower member 9 back frame of backrest 10 flexible sheet material (mesh material)
DESCRIPTION OF SYMBOLS 12 Holding member 15 Edge member 27a Lower member which comprises a front member 27b Upper member which comprises a front member 41 Bearing member which comprises a locking device 43 Lock lever 44 Locking rod which comprises a locking device 33 Lock body which comprises a locking device 56 cushioning material

Claims (5)

The backrest is configured to have a back frame as a strength member and a front member disposed on the front side thereof, and at least a part of the front member is held so as not to be detached from the back frame by a pressing member.
Chair. The pressing member presses a part of the front member from the front, and a portion of the front member excluding a portion pressed and held by the pressing member is held by the engaging means so as not to be detached from the back frame. Yes,
The chair according to claim 1. The lower part of the front member is held by the pressing member in a non-detachable manner on the back frame, and all or most of the pressing member is disposed below the seat surface.
The chair according to claim 1 or 2. The front member has a frame-like shape that opens back and forth, and a flexible sheet material is attached to the front member in a state of being wound from the near side to the back side,
The pressing member is fixed to the back frame with screws, and a resin cushioning material is provided at the rear end of the pressing member so as to contact the lower member of the front member via the flexible sheet material. ,
The chair as described in any one of Claims 1-3. The back frame is attached to the base so as to be able to tilt backward, and the pressing member is fixed to the back frame, while a locking body that is operated by a lever operation on the base prevents the pressing member from moving forward. Arranged so as to be switchable between a locking posture to be performed and a free posture allowing the forward movement of the pressing member,
The chair as described in any one of Claims 1-4.

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