JP2007167541A - Chair - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chair preventing scraping sound generated between a spindle and a bearing part. <P>SOLUTION: A center support body 5 of a seat body 3 is attached to the front of a base 2 with a first shaft 6 in such a way as tiltable. A backrest member 7 is connected to substantially the center in the front/rear direction of the base 2 with a second shaft 8 in such a way as tiltable backward, and the center support body 5 is connected to the backrest member 7 at the center in the front/rear direction with a third shaft 9 in such a way as relatively tiltable. The second shaft 8 has a concentric double-shaft structure consisting of an inner pin shaft 21 made of a metal cylindrical pipe and a half-split cylindrical member 23 made of synthetic resin. When the backrest member 7 is attached to the base 2, the half-split cylindrical members 23 are superposed on each other with the inner pin shaft 21 held between them to make the second shaft 8, and large-diameter overhanging parts 25 of the second shaft 8 are fit into a bearing hole 7h of a forward arm 7a from the right and left sides. After that, a small-diameter stepped part 28 of the second shaft 8 is held between upper and lower center bushes 31 and 32, and is inserted into a center fitting 33. Then, the center fitting 33 is fastened to the base 2 with screws 35. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a chair.

  For example, an office swivel chair has a structure in which a seat is supported by a base fixed to the upper end of a leg and a back support member that tilts backward against a spring means is connected to the rear part of the base. Then, the synchro type in which the seat body moves backward (and / or tilts backward) in conjunction with the backward tilting of the backrest has become the mainstream.

  There are several types of synchro mechanisms for interlocking the backrest and seat, but in any case, rotation and retraction of the member can be achieved by connecting the left and right longitudinal axes (pins) in the front view of the chair. It is common to allow.

  As an example of such a structure, Patent Document 1 discloses a structure of a chair that employs a three-point link mechanism using a shaft (pin) that is long to the left and right in a front view. In this case, the front part of the base and the seat are connected by the first shaft, the back support member to which the backrest is attached and the seat are connected by the second shaft, and the tip of the back support member and the base The rear part is connected to the third shaft so as to be rotatable. Further, the hole into which the first shaft or the third shaft is fitted is a long hole in the longitudinal direction. For this reason, the chair of Patent Document 1 is configured to tilt backward while the seat body moves backward in conjunction with the backward tilting of the backrest.

Each of the above-mentioned shafts is made of a metal round pipe, and is fixed to the back support member and the seat body by welding. A split resin bush is fitted to the left and right ends of each shaft, and the bush portion of each shaft is fitted into a U-shaped bearing hole formed on the base or the like. In this state, the locations of both bushes are covered from above by presser fittings. The presser fitting is fastened to the upper surface of the base or the like with a screw. The split resin bush is for preventing the generation of rubbing noise between a shaft made of a metal round pipe and a member receiving the shaft.
JP 2003-245154 A

  However, when a structure in which a metal round pipe shaft is fixed to a back support member or a seat body by welding as in Patent Document 1, the support strength to the backrest and the seat body is excellent, but a load is applied to the welded portion. Therefore, it has to be carefully welded to ensure a sufficient welding strength, and there is a problem in that the welding process takes a lot of time and the quality varies greatly.

  Further, in the configuration of Patent Document 1, in order to prevent the generation of rubbing noise, it is necessary to arrange a pair of split resin bushes on the left and right with respect to each shaft, so the number of members increases and the number of assembly steps increases. That was also a problem.

  Therefore, the present invention has a technical problem to improve such a current situation.

  In order to solve this technical problem, the invention of claim 1 includes a first member in which a plurality of first bearing portions having concentric bearing holes are provided apart from each other, and a plurality of first members in the first member. A second member having a second bearing portion located between the bearing portions, and the first member and the second member are inserted into the first bearing portion and the second bearing portion. The support shaft is a metal inner pin shaft that serves as a strength member, and a synthetic resin that is fitted to the inner pin shaft so as not to be displaced in the axial direction. It is comprised by the outer case made from a product, and is hold | maintained by the 1st bearing part of the said 1st member, or the 2nd bearing part of the said 2nd member so that it cannot shift | deviate.

  According to a second aspect of the present invention, in the chair according to the first aspect, the outer case of the support shaft is divided into a pair of halved cylindrical members that overlap the outer peripheral surface of the inner pin shaft half by half. A stopper portion that holds the inner pin shaft so as not to be displaced in the axial direction is formed at both ends of the cylindrical member, while the second bearing portion of the second member is formed from the direction orthogonal to the support shaft. A support member fitted on the support shaft is provided, and the support member and the outer case of the support shaft are provided with engagement means for holding both of them in the axial direction of the support shaft so that they cannot be displaced. Is.

  According to a third aspect of the present invention, there is provided the chair according to the second aspect, wherein a leg, a base as the second member supported by the leg, a seat disposed above the base, and a rear of the seat A back support member as the first member disposed; and a backrest provided on the back support member; and a pair of left and right forwards extending forward as part of the first bearing portion on the back support member An arm is formed, and a center pressing member as a part of the second bearing portion is attached to the lower surface of the base, and the support shaft is inserted through the both forward arms and the center pressing member. The back support member and the base are pivotally connected to each other, while the outer shape of each half cylinder member of the outer case constituting the support shaft is such that both left and right end portions are out of the radius of the longitudinal middle portion. Overhang in the direction The length of the small-diameter step portion, which is a midway portion in the longitudinal direction, is set to be approximately the same as the distance between the forward arms of the back support member, and the center pressing member is the support member A pair of upper and lower center bushes that sandwich the support shaft from above and below as a part of the member, and a center metal fitting that covers these upper and lower center bushes from below and is screwed to the base. It is set to be approximately the same as the length of the small diameter step portion in the half cylinder member, and the small diameter step portion of the both half cylinder members and the upper and lower center bushes are arranged so that the small diameter step portion is vertically moved by the upper and lower center bushes. By being pinched, it functions as the engaging means.

  According to the configuration of the present invention, the first member having a plurality of first bearing portions having concentric bearing holes spaced apart from each other and the second member positioned between the plurality of first bearing portions in the first member. Since the second member having the bearing portion is connected by the support shaft that is inserted through the first bearing portion and the second bearing portion, the first member and the second member as in the conventional case are manufactured in the manufacturing stage. There is no need to weld and fix the spindle to any of the members. Therefore, the welding process of the support shaft in the manufacturing stage can be omitted, and the manufacturing cost can be reduced. In addition, since it is not necessary to weld the support shaft to either the first member or the second member, the quality can be made uniform.

  The support shaft is composed of a metal inner pin shaft that serves as a strength member, and a synthetic resin outer case that is fitted to the inner pin shaft so as not to be displaced in the axial direction. Therefore, the outer case made of synthetic resin is interposed between the first and second bearing portions and the inner pin shaft. For this reason, during use of the chair, no rubbing noise is generated between the first and second bearing portions and the inner pin shaft, and as a result, the chair can be used comfortably.

  Furthermore, when connecting the first member and the second member, the support shaft is held in the first bearing portion or the second bearing portion so as not to be displaced. The connection work of the first member and the second member can be efficiently performed, and the efficiency of the chair assembly work can be improved.

  According to the configuration of claim 2, the outer case of the support shaft is divided into a pair of half-cylinder members that overlap each other on the outer peripheral surface of the inner pin shaft, and the inner parts are arranged at both ends of the half-cylinder members. Since the stopper portion that holds the pin shaft in the axial direction so as not to be displaced is formed, both the half-cylinder cylindrical members that exhibit the rubbing noise prevention function can be used as the retaining means for the inner pin shaft. Accordingly, the inner pin shaft can be held so as not to be pulled out from side to side without providing a dedicated member for preventing the disconnection, which can contribute to simplification of the structure (suppression of the number of parts).

  In addition, the second bearing portion of the second member includes a support member fitted to the support shaft from a direction orthogonal to the support shaft, and the support member and the outer case of the support shaft are Since the engaging means for holding both of them in the axial direction of the support shaft is provided so as not to be displaced, the support shaft can be properly displaced with respect to the second member even by the action of the engagement means. And the efficiency of the chair assembling work can be further improved.

  The invention of claim 3 is a more specific embodiment of the structure of claim 2. With this configuration, when the back support member is attached to the base, the small-diameter step portion of the support shaft is sandwiched between the upper and lower center bushes so that the support shaft can be properly positioned with respect to the base so that it cannot be displaced from side to side. Therefore, the connection work between the back support member and the base via the support shaft can be performed efficiently, and as a result, the efficiency of the assembly work of the chair can be improved.

  DESCRIPTION OF EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings (FIGS. 1 to 8). FIGS. 1-7 is an example which applied this invention to the rotation type chair often used for office work. 1 is a front view of a chair, FIG. 2 is a left side view, FIG. 3 is a perspective view of a back support member and a base as viewed from above, and FIG. 4 is an exploded perspective view in a state where the back support member and the base are turned upside down. FIG. 5 is a partially cutaway front view showing the third shaft mounting structure, FIG. 6 is a separated side sectional view showing the third shaft mounting structure, and FIG. 7 is a partially cutout showing the third shaft mounting structure. FIG. 8 is a partially cutaway front sectional view showing another example of the engaging means.

(1). Outline of Chair First, an outline of a chair will be described with reference to FIGS.

  As can be understood from these drawings, the chair of the present embodiment includes a leg 1 having casters and a gas cylinder type pedestal, a base 2 fixed to the upper end of the pedestal, and a seat disposed above the base 2. A body 3 and a backrest 4 disposed behind the seat body 3 are provided.

  The base 2 has a box-like shape opened upward, and is fixed to the upper end of the pedestal via an inner bracket 12 (see FIG. 6) fixed to the rear part. An intermediate support 5, which is a constituent element of the seat body 3, is attached (connected) to the front portion of the base 2 so as to be tiltable about a first shaft 6 that is long in the left-right direction. Further, a back support member 7 is connected to a substantially intermediate portion in the front and back of the base 2 so as to be tilted rearward by a left and right long second shaft 8 as a support shaft. The body 5 is connected to the body 5 so as to be relatively tiltable by a third shaft 9 that is long in the left-right direction.

  The back support member 7 corresponds to the first member described in the claims, and the base 2 corresponds to the second member described in the claims.

  The seat body 3 includes the above-described intermediate support body 5 and a seat 3a on which a person sits. The seat 3a is mounted on the upper surface of the intermediate support body 5 so that the front-rear position can be adjusted. Although not shown in detail, the first shaft 6 is inserted into the base 2 so as to be movable back and forth, and the first shaft 6 is moved backward by a spring (not shown) disposed in the base 2. It is supported from. For this reason, the seat body 3 moves backward while being tilted back in synchronization with the back tilt of the backrest 4 (synchronized).

  The back support member 7 and the base 2 are connected via a gas cylinder 10, and the gas cylinder 10 is switched between a locked state and a free state by rotating the lever 11 disposed outside the back support member 7. By actuating, the backrest 4 is switched between a free state in which the backrest 4 freely tilts back and a locked state in which the backrest 4 is held in a non-reclinable state in any posture. Although not shown, the front end portion of the gas cylinder 10 is rotatably attached to a bracket projecting from the rear end portion of the base 2 by a pin.

  The backrest 4 includes a back frame 13 composed of left and right side members 14 that are vertically long and elongated in front view and an upper member 15 that is connected to the upper end thereof, and a bag-like back sheet 16 that covers the back frame 13. The back frame 13 constitutes the outer shape of the backrest 4, and the portion surrounded by the back frame 13 is open and opened in the front and back to form a space. A lumbar support 17 that mainly supports the lumbar spine of the seated person is disposed in the back seat 14 so as to be movable up and down.

  As shown in FIGS. 3 and 4, the back support member 7 includes a pair of left and right forward arms 7a extending forward as part of the first bearing portion, and the upper surface of these forward arms 7a spans both. A bridge-like bracket 18 made of a metal plate is fixed with screws.

  Both the left and right front arms 7a extend along the left and right outer sides of the base 2, and a bearing hole 7h into which the second shaft 8 is fitted opens in the left and right direction at the front end (front end) of the front arm 7a. It is formed concentrically. The front end portion (front end portion) of the forward arm 7a is connected to the base 2 via the second shaft 8 (details will be described later). A third shaft 9 is rotatably held by a bearing member (not shown) provided on the bridge-shaped bracket 18.

  The back support member 7 is a metal integrally molded product such as an aluminum die-cast, and its rear part is a flat part 7b, and a rear wall part 7c that protrudes up and down at the rear end of the flat part 7b is substantially left and right. It is formed to extend over the entire length. A bank portion 7d protruding upward is formed on the front side of the rear wall portion 7c on the upper surface of the flat portion 7b, and a crescent-shaped portion in plan view extending between the bank portion 7d and the rear wall portion 7c is formed. An edge member fixing portion 7e for fixing the lower end of the back sheet 16 is provided.

  The rear portion of the back support member 7 protrudes left and right, and a boss portion 7f (standing portion) for attaching the side member 14 of the back frame 13 is integrally formed on both of the protruding portions. Although the details are not shown, the side member 14 is made of an elliptical hollow pipe whose cross section is substantially long in the left-right direction, while the boss portion 7f of the back support member 7 is formed in the same planar shape as the side member 14. The side member 14 is fixed to the boss portion 7f via a connecting member (not shown).

  As shown in FIG. 4, the back surface (lower surface) of the flat portion 7b and the front surface of the rear wall portion 7c are connected by a large number of ribs 7g. For this reason, the flat part 7b is formed with a large number of downwardly open recesses 19 surrounded by the rear wall part 7c and the ribs 7g. In these recesses 19, a metal fitting for attaching the gas cylinder 10 and a gas An operation shaft for operating the cylinder 10, a bearing member for holding the operation shaft, and the like are disposed (not shown).

  The back sheet 16 is manufactured from a woven or knitted fabric (net material) having an appropriate gap, and the left and right sides of the front surface portion and the back surface portion are integrally connected by sewing or fusion to form a bag shape. ing. The lower end edge of the front surface portion and the lower end edge of the back surface portion are fixed so as not to be detached by sewing to an edge member (not shown) having an arcuate shape made of a resin plate or a metal plate. These both edge members are fastened together with bolts and nuts to the edge member fixing portion 7e of the back support member 7.

(2). Next, the attachment structure of the back support member and the base via the second shaft will be described with reference to FIGS. 5 to 7 in addition to FIGS. 1 to 4. .

  The second shaft 8 corresponds to the support shaft described in the claims, and is an inner pin shaft 21 made of a metal round pipe that functions as a strength member, and its axial direction (left and right) with respect to the inner pin shaft 21. A concentric double-shaft structure comprising an outer case 22 made of synthetic resin that is fitted in a freely rotatable manner.

  The outer case 22 of the present embodiment is divided into a pair of half-cylinder members 23 that overlap with the outer peripheral surface of the cylindrical inner pin shaft 21 by half a circumference, and both the half-cylinder members 23 have the same shape. It is a common part. These half-cylinder members 23 are preferably made of a material such as polypropylene or polyethylene that does not generate a rubbing sound in contact with metal (the inner pin shaft 21 or the back support member 7). The left and right end portions of each half cylinder member 23 are closed (partitioned) by a substantially semicircular stopper portion 24 formed integrally therewith, so that the inner diameter sides of the half cylinder members 23 are relative to each other. When overlapped so as to face each other, the outer case 22 made of both halved cylindrical members 23 has a hollow cylindrical shape in which both left and right ends are closed. For this reason, the inner pin shaft 21 fitted in the outer case 22 (between the two half-cylinder members 23) is held in a state in which the inner pin shaft 21 can be freely rotated and cannot be shifted left and right.

  The outer shape of each half cylinder member 23 is formed in a stepped shape with both left and right ends projecting radially outward from the longitudinal middle portion, and the large-diameter projecting portions 25 at both left and right ends are forward arms of the back support member 7. It is fitted in the bearing hole 7h of 7a so that it can be inserted and removed from the left and right direction. The length LH of the small-diameter step portion 28 (longitudinal halfway portion) in each half cylinder member 23 is set to be substantially the same as the interval dimension LA between the forward arms 7 a in the back support member 7. The outer end surface of the large-diameter projecting portion 25 is exposed outward from the bearing hole 7h of the forward arm 7a, and has a function as a bearing cap that hides the bearing hole 7h.

  A positioning protrusion 26 is formed on one side and an engagement hole 27 is formed on the other side on the contact end surface (matching surface) of the left and right stopper portions 24 in each half cylinder member 23 (see FIGS. 5 and 7). In a state where the two half cylinder members 23 are overlapped so that the inner diameter sides face each other, the positioning projections 26 of one half cylinder member 23 are fitted into the engagement holes 27 of the other half cylinder member 23. In addition, the positioning (superposition) of the half cylinder members 23 can be easily performed. In addition, on the inner surface of each half cylinder member 23, a number of shallow grooves 23a are appropriately formed. The groove 23a is for smoothening the rotation of the inner pin shaft 21 by, for example, storing grease inside.

  The outer case 22 is not limited to the half-divided cylindrical member 23 and may have a cylindrical shape with open ends through which the inner pin shaft 21 penetrates. In this case, it is only necessary to form annular grooves at both ends of the inner pin shaft 21 and hold the inner pin shaft 21 so as not to be displaced from the outer case 22 by fitting snap rings into these annular grooves. The outer case 22 may be a cylindrical molded product in which the inner pin shaft 21 is internally provided.

  As shown in FIGS. 4 to 7, the second shaft 8 having a double shaft structure is sandwiched from above and below by an upper center bush 31 and a lower center bush 32 made of a synthetic resin such as polypropylene and polyethylene. The bushes 31 and 32 are covered with a flap 34 and covered from below with a bowl-shaped center metal fitting 33. The center metal fitting 33 is fastened to the lower surface of the base 2 with a plurality of screws 35 (four in this embodiment). A female screw hole 2a corresponding to the insertion hole 34a formed in the flap 34 is formed by burring at a portion of the lower surface of the base 2 where the flap 34 of the center metal fitting 33 overlaps. Of course, instead of the female screw hole 2a, a nut may be welded or buried. The upper and lower center bushes 31 and 32 and the center metal fitting 33 correspond to a center pressing member as the second bearing portion described in the claims, and the upper and lower center bushes 31 and 32 correspond to the support members described in the claims. To do.

  The upper and lower center bushes 31 and 32 are formed so that the outer surfaces thereof are substantially rectangular as viewed from the side when overlapped, and are held in the center metal fitting 33 so as not to rattle in a state of overlapping from above and below. In this embodiment, the depth of the upper center bush 31 is made deeper than the lower center bush 32. This is because the second shaft 8 is pushed upward when the chair is rocked (swinged). This is because it is preferable to increase the support function of the upper center bush 31. Of course, the depths of the upper and lower center bushes 31 and 32 may be set to the same level.

  The lengths LB1 and LB2 of the upper and lower center bushes 31 and 32 are set to be substantially the same as the length LH of the halfway portion of each half cylinder member 23 (therefore, the distance LA between the forward arms 7a is also substantially the same). Therefore, when the small-diameter step portion 28 (longitudinal midway portion) of both the half cylinder members 23 in the second shaft 8 is sandwiched between the upper and lower center bushes 31 and 32, the second shaft 8 is 32 is held so as not to be laterally displaced.

  Upward protrusions 31 a that are in contact with or in close contact with the left and right side surfaces of the base 2 are integrally formed at both left and right ends of the upper center bush 31. Further, a pair of left and right engagements that are fitted from below into engagement holes 2b (see FIGS. 4 to 6) drilled in the lower surface of the base 2 at locations between the left and right upward projections 31a of the upper center bush 31. The protrusion 31b is integrally formed. For this reason, the upper center bush 31 is positioned precisely with respect to the base 2, and as a result, the second shaft 8 is held so as not to be laterally displaced with respect to the base 2.

  Further, the lower center bush 32 is integrally formed with a downward projection 32 a that contacts or closely contacts the left and right side surfaces of the center metal fitting 33. For this reason, the lower center bush 32 is accurately positioned in a state in which the center metal fitting 33 and thus the base 2 cannot be shifted left and right.

  In the present embodiment, the small diameter step portion 28 (longitudinal middle portion) of each half cylinder member 23 and the upper and lower center bushes 31 and 32 correspond to the engaging means described in the claims. In addition, the number of shallow grooves 31c and 32c is appropriately formed on the inner surfaces of the upper and lower center bushes 31 and 32 (the function is the same as that of the groove 23a of the half cylinder member 23).

(3). In order to attach the back support member 7 to the base 2 using the second shaft 8, first, the split-half tubular member 23 is overlapped so as to sandwich the inner pin shaft 21, and a double shaft structure is provided. After the second shaft 8 is formed, each large-diameter projecting portion 25 of the second shaft 8 is firmly fitted (inserted) into the bearing hole 7h of the forward arm 7a in the back support member 7 from the left-right direction. Next, the upper and lower center bushes 31 and 32 are overlaid on the small-diameter step portion 28 of the second shaft 8, and then fitted into the center metal fitting 33, and the center metal fitting 33 is fastened to the base 2 with the screw 35.

  In this case, the back support member 7 and the base 2 are connected to the pair of left and right forward arms 7a and the center pressing member by inserting the second shaft 8 from the left and right directions. It is not necessary to weld and fix the second shaft 8 to either the base 7 or the base 2 one by one. Therefore, the welding process of the 2nd axis | shaft 8 in a manufacture stage can be skipped, and manufacturing cost can be reduced. In addition, since it is not necessary to weld the second shaft 8 to either the back support member 7 or the base 2, these qualities can be made uniform.

  Further, the second shaft 8 of the present embodiment has a double shaft structure comprising an inner pin shaft 21 made of a metal round pipe as a strength member and a pair of half cylinder members 23 (outer case 22) made of synthetic resin. Therefore, a half cylinder member 23 made of synthetic resin is interposed between the bearing hole 7f of the forward arm 7a and the center pressing member and the inner pin shaft 21. For this reason, during use of the chair, no rubbing noise is generated between the bearing hole 7f of the forward arm 7a and the center pressing member and the inner pin shaft 21, and as a result, the chair can be used comfortably.

  Further, when the back support member 7 is attached to the base 2, the second shaft 8 is held so as not to be laterally displaced with respect to the base 2 due to the fitting of the downward projection 32 a of the lower center bush 32 and the center fitting 33. The positioning between the female screw hole 2a of the base 2 and the insertion hole 34a of the center metal fitting 33 is simple. Thereby, the connection operation | work of the back support member 7 and the base 2 via the 2nd axis | shaft 8 can be performed efficiently, and the efficiency of the assembly operation | work of a chair improves.

  In the present embodiment, the outer case 22 that constitutes the second shaft 8 is divided into a split half cylinder member 23, and the inner pin shaft in the outer case 22 is provided by the presence of the stopper portions 24 at the left and right ends. Since 21 is held so that it cannot be displaced in the axial direction, the pair of half cylinder members 23 (outer case 22) exhibiting the function of preventing rubbing noise can be used as a retaining means for the inner pin shaft 21. Therefore, the inner pin shaft 21 can be held so as not to be laterally shifted without providing a dedicated member for preventing the disconnection, which can contribute to simplification of the structure (suppression of the number of parts).

  In addition, since the second shaft 8 can be positioned with respect to the base 2 in a state in which the second shaft 8 cannot be displaced left and right even when the second shaft 8 is sandwiched between the upper and lower center bushes 31 and 32 constituting the center pressing member, the second shaft The efficiency of the connecting operation between the back support member 7 and the base 2 via 8 and the assembly work of the chair is further improved.

  In particular, in the present embodiment, the upper center bush 31 is fitted by the upward projection 31a of the upper center bush 31 and the base 2, and the engagement projection 31b of the upper center bush 31 and the engagement hole 2b of the base 2 are engaged. Since 31 is reliably positioned also with respect to the base 2, the effect of improving the efficiency of assembling the chair is extremely high.

(4). Others The present invention is not limited to the above-described embodiment, and can be embodied in various forms. For example, the present invention can be applied to a fixed type chair in which the backrest does not tilt backward (does not rock). The support shaft of the double shaft structure is not limited to the second shaft 8 described above, and may be applied to the first shaft 6 or the third shaft 9.

  In the case where the center pressing member (bush) overlaps with the member such as the base 2, the engaging means for preventing the support shaft from shifting in the axial direction (left-right direction) is not limited to the above-described embodiment. As shown in another example of FIG. 8, an annular groove 41 is formed on the outer peripheral surface of the outer case 22 (both half cylinder members 23), and inwardly-circulating ribs 42 formed on the inner diameter portions of the upper and lower center bushes 31 and 32. May be fitted into the annular groove 41 of the outer case 22 to prevent the lateral shift of the support shaft (second shaft 8 in this example). Moreover, you may employ | adopt the combination of a protrusion and a hole, and the fitting structure of engagement claws. It is sufficient that one of the two engaging claws is elastically deformed. Other engagement structures (locking structures) can also be employed.

  The function of holding the support shaft so that it cannot be displaced may be provided on the forward arm 7 a side of the back support member 7, that is, on the first bearing portion side of the first member. For example, flanges projecting radially outward are formed at both end portions of the outer case 22 (locations closer to the center side by the length of the bearing hole). Due to the presence of this flange, the support shaft (second shaft 8) May be held so that it cannot be displaced outward. Also, the bearing hole 7h portion of the forward arm 7a is divided into two, and an inward annular rib is formed on the inner diameter portion thereof, while an annular groove in which the inward annular rib is fitted is formed at both ends of the outer case 22. You may do it. Furthermore, also in this case, it is possible to employ a combination of a projection and a hole or a fitting structure between engaging claws.

  In addition, in addition, the connection structure between the support shaft and the bearing portion according to the present invention can be applied to various devices and mechanisms other than the chair. In addition, the configuration of each unit is not limited to the illustrated embodiment, and various modifications can be made without departing from the spirit of the present invention.

It is a front view of the chair which concerns on embodiment of this invention. It is a left view of a chair. It is the perspective view which looked at the back support member and the base from the upper part. It is a separation perspective view in the state where the back support member and the base were turned upside down. It is a partial notch isolation | separation front view which shows the attachment structure of a 3rd axis | shaft. It is a separation side sectional view showing the attachment structure of the 3rd axis. It is a partial notch front sectional view which shows the attachment structure of a 3rd axis | shaft. It is a partially cutaway front sectional view showing another example of the engaging means.

Explanation of symbols

2 Base 3 Seat 3a Seat 4 Back 5 Intermediate support 6 First shaft 7 Back member 7a Forward arm 7h Bearing hole 8 Second shaft 9 Third shaft 21 Inner pin shaft 22 Outer case 23 Half cylinder member 24 Stopper part 25 Large-diameter overhanging portion 28 Small-diameter stepped portion 31 Upper center bush 31a Upward projection 31b Engaging projection 32 Lower center bush 32a Downward projection 33 Center bracket

Claims (3)

A first member in which a plurality of first bearing portions having concentric bearing holes are provided apart from each other, and a second member having a second bearing portion located between the plurality of first bearing portions in the first member. And the first member and the second member are connected by a support shaft inserted through the first bearing portion and the second bearing portion,
The support shaft is composed of a metal inner pin shaft that serves as a strength member and a synthetic resin outer case that is fitted to the inner pin shaft so as not to be displaced in the axial direction. In addition, the first bearing portion of the first member or the second bearing portion of the second member is held so as not to be displaced.
Chair. The outer case of the support shaft is divided into a pair of halved cylindrical members that overlap the outer peripheral surface of the inner pin shaft half by half, and the inner pin shafts are arranged in the axial direction at both ends of both halved cylindrical members. While the stopper part is held so that it cannot be displaced,
The second bearing portion of the second member includes a support member that is fitted onto the support shaft from a direction orthogonal to the support shaft, and the support member and the outer case of the support shaft include both of them. An engagement means for holding the support shaft so as not to be displaced in the axial direction;
The chair according to claim 1. A leg, a base as the second member supported by the leg, a seat disposed above the base, a back support member as the first member disposed behind the seat, and a back support With a backrest provided on the member,
A pair of left and right forward arms extending forward are formed on the back member as part of the first bearing part, and a center pressing member as part of the second bearing part is attached to the lower surface of the base. The back support member and the base are rotatably connected by inserting the support shaft through the both forward arms and the center pressing member,
The outer shape of each half cylinder member of the outer case constituting the support shaft has a stepped shape in which both left and right end portions project radially outward from the longitudinal midway portion, and a small diameter step portion which is the longitudinal midway portion. The length is set to be approximately the same as the distance between the forward arms of the back support member,
The center pressing member includes a pair of upper and lower center bushes that sandwich the support shaft from above and below as a part of the support member, and a center bracket that covers the upper and lower center bushes from below and is screwed to the base. The length of the center bush is set to be substantially the same as the length of the small diameter step portion in the half cylinder member,
The small-diameter step portion and the upper and lower center bush of both the half cylinder members function as the engaging means by sandwiching the small-diameter step portion from above and below by the upper and lower center bush.
The chair according to claim 2.

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