JPH0870955A - Seat back cushion mounting structure for chair - Google Patents

Abstract

PURPOSE: To provide a seat back cushion mounting structure for chair, with which a seat back cushion can be mounted on a support plate simply and accurately. CONSTITUTION: A rivet 40 of such a structure that a number of elastic fins 45 are overlapped in the axial direction, is installed on the seat back cushion 30 side, and the shank 41 of this rivet 40 is fitted in rivet detaining holes 23a, 24a which are formed on the support plate 20 side, and the elastic fins 45 on the periphery of the rivet shank 41 are detained with the inner surface protrusive edges 23b, 24b of the detaining holes in such a way that slipping-off is prevented. In this manner the seat back cushion 30 is mounted on the support plate 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a back cushion mounting structure for a folding pipe chair or the like in which a back mounted on a back frame is a combination of a resin back support plate and a back cushion.

[0002]

2. Description of the Related Art The backrest of a folding pipe chair is usually composed of a backrest support plate and a backrest cushion mounted on the front surface thereof. In recent years, a backrest support plate made of a resin molded product has been developed. Has been done.

As such a backrest cushion mounting structure for a backrest, for example, a nut such as a T nut is embedded and fixed in the core plate of the backrest cushion, and a screw is passed through the backrest support plate from the back side and fastened to the nut. The ones that have been made are generally adopted.

[0004]

However, in the above-mentioned conventional structure, there is a problem that the troublesome nut embedding work and the screw fixing work are required, and the back cushion cannot be easily attached to the backrest support plate. In addition, since it is necessary to hold the back cushion in a state of being positioned with respect to the backrest support plate when performing the screw fixing work, it is necessary to perform positioning and screw fixing in parallel at the same time. Also, the back cushion mounting work is made more complicated.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and to provide a backrest cushion mounting structure for a chair in which the backrest cushion can be easily and accurately mounted on the backrest support plate.

[0006]

In order to achieve the above object, the present invention provides a backrest of a chair in which a backrest attached to a backrest frame extending above a seat body comprises a backrest support plate and a backrest cushion attached to the front thereof. A cushion mounting structure, wherein the backrest support plate has a backrest cushion mounting recess on the front surface,
Further, a rivet engaging projection is integrally formed at a predetermined position on the bottom surface of the recess, and a rivet engaging hole having a rivet engaging inward convex edge is formed on the peripheral edge at the tip of the rivet engaging projection. The back cushion is formed of a molded product, the backrest cushion has a core plate in which a rivet installation hole is formed at a position corresponding to the rivet engaging projection, and the head part is in a state in which a shaft portion is inserted into the rivet installation hole. A rivet arranged so as to engage with the peripheral portion of the rivet setting hole on the front side of the core plate, a cushion material arranged so as to cover the front side of the core plate, and a cushion material for covering the cushion material from the front side. The cover sheet to be arranged is provided, and the rivet has a large number of elastic fin pieces arranged in a dense arrangement along the axial direction on the outer peripheral surface of the shaft portion. The shaft portion of the rivet is fitted into the rivet engaging hole, and the elastic fin piece is engageably and disengageably engaged with the inner peripheral convex edge for rivet engaging in a state in which the shaft is arranged in the recess for mounting the back cushion. Accordingly, the gist is that the back cushion is attached to the back support plate.

In the present invention, the rivet engaging inner peripheral convex edge is formed so as to become thinner toward the inner diameter direction, and the rivet engaging hole is formed in the countersink. good.

Further, in the present invention, the rivet engaging projecting portion is formed in a tubular shape, and the rivet engaging hole is formed at the tip thereof so as to be surrounded by the rivet engaging inner peripheral convex edge, while the core is provided. The rivet and the rivet engaging hole are formed in a state where the rivet installing hole of the plate is formed to have a diameter larger than the outer diameter of the rivet engaging protruding section and the rivet engaging protruding section is inserted into the rivet installing hole. It is desirable to adopt a configuration in which engagement with the convex edge is achieved.

Further, in the present invention, it is preferable to adopt a constitution in which a region where the rivet head portion of the core plate is arranged is subjected to a counterboring treatment, and the head portion of the rivet is housed and arranged in the countersunk portion. preferable.

Further, in the present invention, it is even more preferable that the axis line of the rivet shaft portion is arranged in parallel with the center line of the backrest extending in the front-rear direction.

[0011]

In the chair backrest cushion mounting structure of the present invention, the rivet provided on the backrest cushion side is fitted into the rivet engaging hole formed on the backrest support plate side, and the elastic fin piece on the outer periphery of the rivet shaft is rivet engaged. Since the back cushion is attached to the support plate by engaging with the convex edge of the inner peripheral edge of the hole, the back cushion is placed on the front side of the support plate to support the rivet installation position of the back cushion. When pushed to the plate side, the rivets are engaged, and the back cushion and the support plate are reliably connected.

As a rivet, on the outer peripheral surface of the shaft,
Since the one having a large number of elastic fin pieces in a dense arrangement along the axial direction is used, the rivet can be engaged with the rivet engaging inner peripheral convex edge at any position on the shaft portion, which is reasonably possible. The rivet can be engaged at an appropriate pushing position.

In the present invention, the inner peripheral convex edge for rivet engagement becomes thinner toward the inner diameter.
When the rivet engaging hole is formed in the countersink, the elastic fin piece of the rivet shaft portion is engaged with the tip of the thin-walled inner peripheral convex edge, and the engagement is surely performed. It is possible to reliably prevent the occurrence of a problem such as the back cushion being unintentionally peeled off.

In the present invention, when the rivet is engaged in the state where the tubular rivet engaging protrusion on the backrest support plate side is inserted into the rivet setting hole on the backrest cushion side, the rivet is adopted. Since the protruding dimension of the rivet engaging protrusion can be made longer by the depth dimension of the installation hole, it is possible to secure a sufficient amount of fitting of the rivet shaft portion into the engaging hole, and to provide a slight dimension in the axial direction. Even if there is an error, the rivet can be reliably engaged, and when the back cushion is overlapped with the support plate, the rivet engaging protrusion is inserted into the rivet setting hole, so that the backrest is The cushion can be positioned with respect to the support plate.

In the present invention, in the case of adopting a structure in which a region of the core plate where the rivet head is arranged is subjected to a spot facing treatment and the rivet head is accommodated and arranged in the spot facing portion, the rivet head The amount of protrusion from the front of the core plate decreases,
After the chair is assembled, the seated person does not feel the rigid feeling of the rivet head.

In the present invention, the axis of the rivet shaft is
If the backrest center line extends in the front-rear direction and is parallel to the backrest centerline, the direction in which the backrest cushion overlaps the support plate and the direction in which the rivets engage are the same, and the direction in which the rivets are pushed in is incorrect. As a result, the rivets can be reliably engaged.

[0017]

1 is a view showing a folding pipe chair to which an embodiment of the present invention is applied. As shown in the figure, the middle of both sides of the substantially U-shaped metal pipe for forming the front leg (1) and the backrest frame (3) (3) is pivotally attached to both sides of the seat body (4). The upper portions of both sides of the U-shaped pipe, that is, the backrest frames (3) and (3) are arranged so as to extend parallel to each other above the seat body (4), and the backrest frames (3) and (3). A backrest (10), which will be described in detail later, is attached between the upper ends of the.
Further, the upper portions on both sides of the substantially U-shaped metal pipe forming the rear leg (2) are pivotally attached to the rear portions on both sides of the seat body (4), and the upper ends of the rear legs (2) are on the backrest frame (3).
It is pivotally attached to the lower end of (3) via a connecting member (5).

In the chair of this construction, the seat body (4) and the rear legs (2) are rotated so that the front part of the seat body (4) is rotated, if necessary. ) And the backrest frame (3), so that they can be folded compactly.

As shown in FIGS. 2 to 8, the backrest (10) attached to the backrest frame (3) is formed in a curved shape so as to be along the back surface of the occupant. It comprises a backrest support plate (20) and a curved backrest cushion (30) provided on the front side of the support plate (20).

The backrest support plate (20) is made of a resin molded product, and one half of a joint pipe (21) made of a metal such as an aluminum alloy is embedded in a position where the backrest frame (3) is connected. Is stuck to.

This joint pipe (21) is fixed by being insert-molded when the backrest support plate (20) is resin-molded. A cap (21a) for prevention is fitted, and a recess (21b) for preventing slipping out and rotation due to resin entanglement is formed in the peripheral wall portion of the embedded region.

Further, a pin hole (21c) is formed on the rear surface side of the projecting portion of the joint pipe (21).

A backrest cushion mounting recess (22) is formed on the front side of the backrest support plate (20),
The rivet engaging protrusions (2) are protruded forward at four positions on the bottom surface of the recess (22) in the vertical and horizontal positions.
3) (24) are integrally formed.

The rivet engaging projections (2
As shown in FIG. 9A, 3) and (23) are formed in a tubular shape, and have a rivet engaging inner peripheral convex edge (2) at the tip thereof.
Rivet engagement holes (23a) and (23a) are formed so as to be surrounded by 3b) and (23b). The rivet engaging hole (23a) is provided with a rivet engaging inner peripheral edge (23a).
The b) is formed so as to become thinner toward the inner diameter direction, so that it is formed in the countersink.

As shown in FIG. 9 (b), the rivet engaging protrusions (24) and (24) at the left and right sides are formed with elliptical plate-like tips at the center of the protrusions. A rivet engaging hole (24a) surrounded by the inner peripheral convex edge (24b) is formed. The engagement hole (24
A) is also formed in the countersink like the above.

In FIG. 7, (25) is a rib integrally formed on the backrest support plate (20), and (26) is integrally formed on the backrest support plate (20) to provide a back cushion (30). It is a cylindrical spacer portion for abutting against and maintaining a distance from it.

On the other hand, the back cushion (30) has a plywood core plate (31) formed in a curved shape following the backrest support plate (20). Core plate (31)
At the upper, lower, left and right positions of the rivet engaging projection (2
Four rivet setting holes (33) and (34) are formed corresponding to 3) and (24), respectively.

These rivet setting holes (33) (34)
The rivets placed on the rivets are special resin rivets called Christmas rivets, Christmas clips, etc. (4
0) is used. That is, this rivet (40)
As shown in FIG. 10, a large number of elastic fin pieces (45) are integrally formed on the outer peripheral surface of the shaft portion (41) in a dense arrangement along the axial direction, and the rivet (4
0) has its shank (41) with rivet setting holes (33) (3
4) It is inserted into the core plate and protrudes to the back surface side of the core plate, and the peripheral edge portion of the head portion (42) is locked to the peripheral edge portions of the rivet setting holes (33) (34) on the front surface side of the core plate (31). It is located in.

The rivet setting holes (33) (34)
Are formed in so-called foolish holes, that is, the diameters of the rivet setting holes (33) and (34) are different from those of the rivet (4).
The rivet (40) is formed to be much larger than the diameter of the shaft portion (41) of (0) so that the rivet (40) can be slightly moved in the radial direction orthogonal to the shaft portion (42).

On the front surface of the core plate (31), rivets (4
The rivet holding sheet piece (35) is attached by tacking or adhering so as to cover the head (42) of (0).

Further, a cushion material (36) is arranged on the front side of the core plate (31), and a covering sheet (37) is arranged so as to cover the cushion material (36), and the covering sheet (37). ) Is fixed to the back side peripheral edge of the core plate (31) by tacking, thereby forming a back cushion (30).

Back cushion (30) of this construction
2 and 3, the rivet (40) is attached to the backrest support plate (20) by engaging the rivet engaging holes (23a) and (24a) with each other. That is, the back cushion (30) is attached to the back cushion supporting recess (2) on the front side of the back support plate (20).
2), and the rivet installation position of the back cushion (30) is pushed into the backrest support plate (20) side.
At this time, first, the rivet (40) is lightly pushed in to move the rivet shaft portion (41) into the rivet engaging holes (23a) (24).
a) A small amount is inserted into the inside of a), and at a relatively shallow position, the elastic fin pieces (45) (45) of the rivet shaft portion (40) are prevented from coming off from the inner peripheral convex edges (23b) (24b) of the inner peripheral edge portion of the rivet engaging hole. Engagement to form a temporary stop for the back cushion (30). In the temporarily fixed state, it is confirmed whether or not there is any problem. If there is no problem, the rivet (40) is strongly pushed into the backrest support plate (20) side, and the rivet shaft portion (41).
Is deeply inserted into the rivet engaging holes (23a) (24a),
At that position, the elastic fin piece (45) is engaged with the rivet engaging inner peripheral convex edges (23b) and (24b) in a retaining manner to perform final fixing.

At the time of this fixing, since the rivet setting holes (33) (34) of the core plate (31) are formed to have a large diameter (dumb hole), the rivet (40) and the rivet engaging hole (23).
a) (24a), even if there is some dimensional error in the direction orthogonal to the axial direction, the rivet (4
Since 0) moves so as to absorb the error, the rivet (40) can be reliably engaged.

On the other hand, in the backrest (10) assembled in this way, as shown in FIG. 5, the joint pipes (21) (21) at both sides are inserted into the upper ends of the pair of backrest frames (3) (3). Further, as shown in FIG. 6, a connecting pin (6) such as a blind rivet is inserted and fixed in the pin hole (3c) formed in the backrest frame (3) and the pin hole (21c) of the joint pipe (21). Backrest frame (3) and joint pipe (2
Connect with 1).

As a result, the backrest (10) is attached to the backrest frame (3), and the chairs are set up in the set.

According to this embodiment, the back cushion (30) is arranged on the front side of the support plate (20), and the rivet setting position of the back cushion (30) is set to the support plate (2).
If the rivet (40) is engaged by pushing it to the (0) side, the back cushion (30) and the support plate (20) can be easily connected.

Further, the rivet engaging holes (23a) (24
Since (a) is a countersink, the inner peripheral convex edge of the inner peripheral edge of the engaging hole is formed thin, and the rivet (4) is formed on the thin inner peripheral convex edge.
Since the elastic fin piece (45) of 0) can be engaged, it is possible to surely prevent a defect due to poor engagement, for example, a problem in which the back cushion (30) is unintentionally peeled off.

Further, as the rivet (40), a large number of elastic fin pieces are formed on the outer peripheral surface of the shaft portion in a dense arrangement along the axial direction, and therefore, on the shaft portion (41). The rivet (40) can be engaged at any position, and the rivet can be engaged at a reasonable and appropriate pushing position, so that the backrest can be assembled accurately and surely. Further back cushions (3
0) can be fixed at any position in the pushing direction, so that the back cushion (30) can be temporarily fixed in the middle of mounting, and the positioning can be accurately performed in the temporarily fixed state. After reconfirming whether or not the back cushion has been broken, the back cushion (30) can be firmly pushed in to firmly fix it. Therefore, after the main fixing, there is no need for the troublesome work of disassembling and assembling again due to misalignment or the like.

In this embodiment, the back cushion (30) can be easily separated from the support plate (20) by peeling off the back cushion (30) from the back support plate (20). Also in this case, the back cushion (30) and the support plate can be maintained and inspected without any trouble.

Also according to this embodiment, the backrest (10)
Since the joint pipe (21) is fixed to the support plate (20) in advance in an embedded state by insert molding, the joint pipe (21) is inserted into the backrest frame (3) to connect the two together ( The backrest (10) can be easily attached to the backrest frame (3) simply by connecting the backrest (6). Further, since only the joint pipe (21) and the connecting pin (6) are used as the connecting member, the number of parts can be reduced, and the structure can be simplified and the cost can be reduced.

In this embodiment, the joint pipe (2
Since the cap (21a) is attached to the opening end on the embedded side of 1), resin is prevented from entering the joint pipe (21) when the support plate (20) is molded, and a good molded product, that is, The backrest support plate (20) can be obtained and a high quality chair can be manufactured.

Moreover, when the two joint pipes (21) on both sides of the backrest (10) are inserted into the pair of backrest frames (3), the rotational position of the joint pipe (21) with respect to the backrest frame (3) is constant. Therefore, when the joint pipe (21) is inserted, the pin hole (21c) of the joint pipe (21) and the pin hole (3c) of the backrest frame (3) are automatically positioned. Therefore, the work of adapting the pin holes, which requires a high degree of skill, is not required, and also in this respect, the assembling work can be easily performed.

Further, since the joint pipe (21) is attached with high positional accuracy by insert molding and the joint pipe (21) with high positional accuracy serves as the core material, the chair can be assembled with high precision and high quality is achieved. Can provide a chair.

11 and 12 are plan sectional views showing the backrest side portions of a folding pipe chair according to a modification of the present invention, showing the portions corresponding to FIGS. 3 and 4 of the above embodiment, respectively. There is.

As shown in both figures, this backrest (11
0) is the same as above, and the backrest support plate (12) made of resin, to which the joint pipe is fixed by insert molding.
0) and a back cushion (130).

Rivet engaging projections (123) (124) are integrally formed at four positions on the backrest cushion mounting recess (122) bottom surface of the backrest support plate (120).

These rivet engaging protrusions (123)
Each of the (124) is configured by a cylindrical member having a longer axial direction than the rivet engaging protrusion (23) at the upper and lower positions of the above-mentioned embodiment, and the inner peripheral convex edge (1
23b) and 124b are provided with countersink-shaped rivet engagement holes (123a) (124a). Further, the rivet engaging protrusion (123) at the upper and lower positions
Of the backrest (110) is aligned with the centerline C1 of the backrest (110) in a plan view, and the axislines C2 of the left and right rivet engaging protrusions (124) are parallel to the backrest centerline C1. Is configured to be placed.

On the other hand, on the front surface side of the core plate (131) of the back cushion (130), the positions corresponding to the above-mentioned four rivet engaging projections (123) (124) are countersunk to install the rivet head. Counterbore part (131a)
And a rivet setting hole (133) (134) having a larger diameter than the rivet engaging protrusions (123) (124) is formed from the center of the bottom surface of the counterbore (131a) to the back side of the core plate. Has been done. The rivet setting holes (133) and (134) are configured such that the axis C2 thereof is parallel to or coincides with the backrest center line C1 in a plan view.

Furthermore, the rivet (4
0) has its shank (41) with a rivet setting hole (133)
The head (42) when inserted and arranged in the (134)
It is arranged so as to be housed in the counterbore (131a) and to be locked to the peripheral portions of the rivet setting holes (133) (134) on the bottom surface of the counterbore. The rivet (40) thus arranged is configured such that its axis C2 is parallel to or coincides with the backrest centerline C1 in a plan view.

In FIGS. 11 and 12, (1
Reference numeral 25) is a rib which also serves as a spacer for reinforcing the rivet engaging protrusions (123) (124) and the backrest support plate (120) and for maintaining a distance from the backrest cushion (130).

Since the other construction is substantially the same as that of the above-mentioned embodiment, the same or corresponding portions are designated by the same or corresponding reference numerals, and the duplicated description is omitted.

The back cushion (13
0) is attached to the backrest support plate (120) in the same manner as above. That is, the rivet engaging protrusion (1
23) and (124) are rivet setting holes (133) and (13).
4) The back cushion (130) is superposed on the front surface of the backrest support plate (120) so as to be inserted into the inside, and the rivets (40) are pushed into the rivet engaging protrusions (123) (124), respectively. (40)
The shaft portion (41) of the rivet engaging hole (123a) (124
a), and the inner peripheral convex edge (123b) (124)
The elastic fin piece (45) is engaged with b) in a retaining manner to connect the back cushion (130) and the support plate (120).

In this modification, in addition to the effects of the above embodiment, rivet setting holes (133) (134) are further added.
Since the rivet engaging protrusions (123) and (124) are inserted into the inside, the rivet setting hole (13)
3) The protrusion dimension of the rivet engaging protrusions (123) and (124) can be increased by the depth dimension of (134). Therefore, the engaging hole (12) of the rivet (40)
3) A sufficiently large amount of fitting into the (124) can be secured, and even if there is a slight dimensional error in the axial direction, the dimensional error can be absorbed and the rivet (40) can be reliably engaged. You can

Further, when the back cushion (130) is overlaid on the support plate (120), the rivet engaging projections (123) (124) are provided with rivet setting holes (13).
3) Since the back cushion (130) is positioned with respect to the support plate (120) by being inserted into (134), the backrest assembling work can be performed more accurately and easily.

Further, by performing the counterbore treatment, the amount of protrusion of the rivet head (42) from the front surface of the core plate (131) is reduced, and after the chair is assembled, the seated person feels a hard feeling of the rivet head (42). It is possible to provide a comfortable chair that is comfortable and comfortable for the seated person.

By the way, in the backrest (10) of the embodiment shown in FIG. 4, the axis C3 of the rivets (40) at both sides forms a predetermined angle with respect to the centerline C1 of the backrest, and the backrest cushion (30). ) And the engaging direction of each rivet (40) are different, an operator with a low degree of skill may not be able to grasp the pushing direction of the rivet (40) quickly and accurately, resulting in deterioration of workability. There is a risk of coming. On the other hand, the backrest (11
0), the rivet (40) is arranged with its axis C2 parallel to the backrest centerline C1, as shown in FIGS.
Since the stacking direction of 30) and the engaging direction of each rivet (40) are the same direction, even a worker with a low degree of skill will not make a mistake in the pushing direction of the rivet (40), and The backrest can be assembled more easily.

In the present invention, the rivet mounting position and the number of mounted rivets are not particularly limited.

[0058]

As described above, according to the chair backrest cushion mounting structure of the present invention, the rivet provided on the backrest cushion side is fitted into the rivet engaging hole formed on the backrest support plate side, and the rivet shaft is attached. By engaging the elastic fin piece on the outer periphery with the inner peripheral convex edge of the inner peripheral edge of the rivet engaging hole, the back cushion is attached to the support plate, so the back cushion should be placed on the front side of the support plate. , The back cushion can be easily attached to the backrest support plate simply by pushing the rivet installation position of the backrest cushion to the support plate side. Further, as the rivet, which has a large number of elastic fin pieces arranged closely on the outer peripheral surface of the shaft portion along the axial direction is used, the rivet should be engaged at any position on the shaft portion. Therefore, the rivet can be engaged at a proper and appropriate pushing position, and the backrest can be assembled accurately and surely.

In the present invention, when the rivet engaging inner peripheral convex edge is formed so as to become thinner toward the inner diameter direction and the rivet engaging hole is formed in the countersink, the rivet shaft is provided at the tip of the thin inner peripheral convex edge. Since the elastic fin piece of the portion is engaged, the engagement is surely performed, and it is possible to surely prevent a defect due to poor engagement, for example, a problem in which the back cushion is unintentionally peeled off. There is an advantage.

In the present invention, the rivet is engaged with the rivet engaging inner peripheral convex edge with the tubular rivet engaging projecting portion on the backrest supporting plate side being inserted into the rivet setting hole on the backrest cushion side. When adopting the configuration, the protrusion size of the rivet engagement protrusion can be made longer by the depth dimension of the rivet installation hole, so a sufficient amount of rivet shaft fitting can be secured, and some dimensional error in the axial direction Even if there is such a problem, the rivet can be engaged and the backrest can be reliably assembled, and when the backrest cushion is pushed into the support plate, the rivet engaging protrusion is inserted into the rivet setting hole. Since the back cushion is positioned with respect to the support plate, the backrest assembly work can be performed more easily and accurately. A.

In the present invention, in the case of adopting a structure in which the region where the rivet head portion of the core plate is arranged is subjected to a counterboring treatment and the rivet head is housed and arranged in the countersunk portion, when the rivet head portion is The amount of protrusion from the front of the core plate decreases,
After the chair is assembled, the seated person does not feel the rigid feeling of the rivet head, and there is an advantage that the seated person can provide a comfortable and comfortable chair.

In the present invention, the axis of the rivet shaft is
When arranging it so that it is parallel to the center line of the backrest that extends along the front-rear direction, the direction in which the back cushion is laid on the support plate and the direction in which the rivets engage are the same, and the direction in which the rivets are pushed in may be wrong. There is an advantage that the backrest can be assembled more easily.

[Brief description of drawings]

FIG. 1 (a) is a front view showing a folding pipe chair to which a back cushion mounting structure according to an embodiment of the present invention is applied, and FIG. 2 (b) is a side view showing the folding pipe chair. .

FIG. 2 is a perspective view showing a side portion of a backrest of the chair of the embodiment with a backrest cushion separated.

FIG. 3 is a plan cross-sectional view showing a side portion of a backrest in an embodiment with a backrest cushion separated.

FIG. 4 is a plan sectional view showing a side portion of a backrest according to an embodiment.

FIG. 5 (a) is a front sectional view showing a backrest of the embodiment separated from a backrest frame, and FIG. 5 (b) is a front sectional view showing the backrest connected to a backrest frame.

FIG. 6 is a perspective view showing a joint pipe embedded in the backrest of the embodiment.

FIG. 7 is a front view showing a backrest support plate in the backrest of the embodiment.

FIG. 8 is a rear view showing the back cushion of the chair of the embodiment.

9 is a perspective view showing a rivet engaging protrusion formed on the backrest support plate of the embodiment, and FIG. 9 (a) is a perspective view showing the rivet engaging protrusions located in the upper and lower parts of the center. (B) is a perspective view which shows the protrusion part for rivet engagement on both sides.

FIG. 10 is a perspective view showing a rivet applied to the embodiment.

FIG. 11 is a plan cross-sectional view showing a side portion of a backrest in a modified example of the present invention with a backrest cushion separated.

FIG. 12 is a plan sectional view showing a side portion of a backrest in a modified example.

[Explanation of symbols]

3 ... Back frame 4 ... Seat 10, 110 ... Back 20, 20 ... Back support plate 22, 122 ... Back cushion mounting recess 30, 130 ... Back cushion 23, 24, 123, 124 ... Rivet engaging protrusion 23a, 24a, 123a, 124a ... Rivet engaging hole 23b, 24b, 123b, 124b ... Rivet engaging inner peripheral convex edge 31, 131 ... Core plate 33, 34, 133, 134 ... Rivet setting hole 36 ... Cushion material 37 ... Cover sheet 40 ... Rivet 41 ... Shaft 42 ... Head 45 ... Elastic fin piece 131a ... Counterbore C1 ... Backrest centerline C2 ... Rivet Shaft axis

Claims (5)

[Claims] 1. A backrest cushion mounting structure for a chair, wherein a backrest mounted on a backrest frame extending upward from a seat body comprises a backrest support plate and a backrest cushion mounted on the front surface thereof, wherein the backrest support plate is mounted on the front surface. It has a recess for mounting the back cushion, a rivet engaging protrusion is integrally formed at a predetermined position on the bottom surface of the recess, and a rivet engaging inward convex edge is formed on the peripheral edge at the tip of the rivet engaging protrusion. A core plate having a rivet setting hole formed at a position corresponding to the rivet engaging projection,
A rivet arranged so that the head portion is locked to the rivet setting hole peripheral portion on the front surface side of the core plate in a state where the shaft portion is inserted into the rivet setting hole, and covers the front surface side of the core plate. A cushion material to be arranged and a covering sheet arranged to cover the cushion material from the front side are provided, and the rivet has a large number of dense arrangements along the axial direction on the outer peripheral surface of the shaft portion. An elastic fin piece is used, and the shaft portion of the rivet is fitted into the rivet engagement hole in a state where the back cushion is arranged in the back cushion mounting recess, and the elastic fin piece is rivet engaged. By being engageably and disengaged with the inner peripheral convex edge,
A backrest cushion attachment structure for a chair, wherein the backrest cushion is attached to the backrest support plate. 2. The inner peripheral convex edge for rivet engagement is formed so as to become thinner toward the inner diameter direction,
The backrest cushion mounting structure for a chair according to claim 1, wherein the rivet engaging hole is formed in a countersink. 3. The rivet engaging protrusion is formed in a tubular shape, and the rivet engaging hole is formed at the tip of the rivet engaging protrusion so as to be surrounded by the rivet engaging inner peripheral convex edge, while the rivet mounting of the core plate is performed. A hole is formed with a diameter larger than the outer diameter of the rivet engaging protrusion, and the rivet engaging protrusion is inserted into the rivet setting hole. The back cushion mounting structure for a chair according to claim 1 or 2, wherein engagement is achieved. 4. A counterbore treatment is applied to a region of the core plate where a rivet head is arranged, and the head of the rivet is housed and arranged in the countersunk portion. Backrest cushion mounting structure of the chair. 5. The chair backrest cushion mounting structure according to claim 4, wherein an axis of the rivet shaft portion is arranged parallel to a backrest center line extending in the front-rear direction.