JP2020039466A - Chair - Google Patents

Abstract

To provide a structure in which a backrest and back support can be easily connected without machine screws.SOLUTION: A back surface of a backrest (a back plate) 2 is provided with left and right bracket parts 41, and to the bracket parts 41, an upper part of a joint member 44 is connected with a pin 45. A left and right edge parts of the pin 45 are exposed parts protruding outside the bracket parts 41. In an upper end part of a back support 18, a holding part 52 into which the joint member and the bracket parts 41 enter is formed. On an inner wall 53 provided with the holding part 52, a bearing groove 54 with which an exposure part of the pin 45 is engaged with from above is formed. Both the joint member 44 and the holding part 52 are connected by engagement between the engaging claw 55 and an engaging boss part 57. Connection of the backrest 2 to the back support 18 is performed by simple operation to press the joint member 44 against the back support 18 after the pin 45 is fallen in the bearing groove 54. The pin 45 is held in the way that it cannot fall off by the holding part 52 and is invisible.SELECTED DRAWING: Figure 11

Description

  The present invention relates to a chair characterized by a mounting structure for a backrest.

  There are various types of chairs, and there are various types of backrests and mounting structures, but there is a demand for improved fit and cushioning. Therefore, Patent Document 1 discloses a structure in which a backrest is configured such that a number of elements are connected by hinges, and the lower end of the backrest is rotatably connected to a seat receiving member such as a seat outer shell. A chair is disclosed in which a midway portion is rotatably connected to a back support so that the form of a backrest can be changed by the body pressure of a seated person.

  In this Patent Document 1, in connecting the upper and lower middle portions of the backrest to the back strut with pins, a pin is inserted into the upper end of the back strut and both ends are exposed on the left and right sides of the back strut. An insertion hole to be fitted from above is formed in the exposed portion of the pin, and the exposed portion of the pin is undetachably held by a pressing member fixed to the backrest with screws.

JP 2017-86375 A

  The backrest of Patent Literature 1 is excellent in followability of the shape change to the movement of the occupant. For example, when the occupant twists the upper body, the upper element is intensively deformed, so that high fit can be secured. With such advantages, it can be evaluated as an unprecedented innovative chair. Therefore, it can be said that various functions can be developed by utilizing the functions, but from a structural point of view, there is room for improvement in the development.

  For example, in connecting the upper and lower middle part of the backrest to the back column with a pin, the connection state is maintained by a holding member fixed with screws, but if a holding member is used, the work of fastening takes time or holding There is a problem that the structure cannot be applied to a backrest having a structure in which the member cannot be fixed from the near side. Therefore, a structure that can be beautifully and easily connected without using a pressing member is required.

  The present invention has been made in view of such a situation, and aims to provide an improved technique for connecting a backrest to a back support.

The present invention includes various configurations, and typical examples thereof are specified in each claim. Of these, the invention of claim 1 is:
`` A chair comprising a backrest and a back strut arranged behind the backrest, wherein the backrest is connected to the back strut via left and right longitudinal pins,
A left and right bracket portion is provided on one of the backrest and the back support, and a joint member is relatively rotatably connected to the left and right bracket portions via the pin.
On the other of the backrest and the back strut, a holding portion having left and right side plates on which the pin is held so that the pin cannot be left and right is formed, and the holding portion has a bearing groove into which the pin is dropped. Has formed,
Further, an engaging portion (engaging means) is formed on the holding portion and the joint member, the engaging portion being engaged in the front-rear direction and holding the pin so that the pin cannot be removed from the bearing groove. "
It is a configuration.

As a preferable development example of claim 1, in the invention of claim 2,
"While the left and right brackets project from the back of the backrest, and the bracket is connected to the joint member by the pins,
The back strut has a U-shape in cross section having left and right side plates facing the backrest, the holding portion is formed at an upper end portion, and the engaging portion is formed between the back strut and a joint member. Is forming. "
It is a configuration.

According to a third aspect of the present invention, in the first or second aspect,
"The engaging portion is constituted by an engaging claw having a hook at a tip and a cylindrical engaging boss portion into which the engaging claw is fitted."
It is a configuration.

According to a fourth aspect of the present invention, in the second or third aspect,
"A receiving rib having a forwardly inclined posture for supporting the pin pushed backward by the body pressure of the occupant from behind is formed in the holding portion."
It is a configuration. The forward leaning posture specified in claim 4 means that the surface on which the pin contacts is in the forward leaning posture.

According to a fifth aspect of the present invention, in the fourth aspect,
"The joint member is provided with an upper surface plate located below the receiving rib, and an upper piece is provided at a front end of the upper surface plate."
It is a configuration.

  In the present invention, the backrest is moved toward the back column to drop the pin into the bearing groove, and in this state, when the joint member is pressed against the member to engage the engaging portions with each other, the pin cannot be removed from the bearing groove. Retained, the backrest is attached to the back column.

  Therefore, the backrest can be irremovably connected to the back support by a very simple operation. Further, since the pins are covered from the left and right sides by the side plate of the holding portion, the pins do not come off, and the pins are not exposed and the appearance is not spoiled. Therefore, in the present invention, the connection of the backrest to the back support can be easily performed without using screws while maintaining a beautiful appearance.

  It is also possible to form a holding portion on the backrest and connect the joint member to the back support, but in this case, since the holding portion is exposed outside the back support, the back support and the holding portion are connected. There is a possibility that the boundary may be exposed to human eyes and deteriorate the aesthetic appearance. On the other hand, when the joint member is connected to the backrest and the holding portion is provided on the back support, the member such as the joint member can be completely covered by the holding portion provided on the back support. For this reason, the appearance can be improved with a neat appearance.

  Various combinations can be adopted for the engaging portion. However, when a combination of the engaging claw and the cylindrical engaging boss portion is adopted, the movement of the engaging claw is restricted by the cylindrical engaging boss portion. Therefore, there is an advantage that the holding of the engaged state can be ensured. In addition, when the positioning means by fitting the positioning protrusion and the positioning hole is used in addition to the engaging portion, the movement of the backrest can be prevented from spreading to the engaging claw, so that the effect of maintaining the engaged state is further improved. it can.

  When the seated person leans against the backrest, the body pressure acts as a pressing force on the bearing groove of the holding part via the pin, but if the pressing force applied to the pin is supported only by the bearing groove, a large bending There is a possibility that durability is reduced due to the force acting. Further, if the component force of the body pressure acts to move the pin upward, the pin comes out of the bearing groove and becomes selfish.

  On the other hand, when the configuration of claim 4 is adopted, since the rib can be supported by the pressing force, the load on the pin can be reduced and the durability of the pin can be improved. In addition, since the receiving rib is in the forwardly inclined posture, the pin is guided downward by the rearward pressing force, and tends to fit deeply into the bearing groove. For this reason, it is possible to prevent the pins from moving in the direction of coming out of the bearing grooves, and to tilt the backrest backward without rattling.

  If the resin powder is used for a long period of time, resin powder may come out from the receiving ribs, which may fall on the floor or the like and impair the aesthetic appearance. Since it can be received by the top plate of the joint member, it is possible to prevent the appearance from being deteriorated.

It is a figure which shows the external appearance of a chair, (A) is a front perspective view, (B) is a front view, (C) is a side view. It is a figure which shows the external appearance of a chair, (A) is a rear view, (B) is a rear perspective view, (C) is a top view. It is a front perspective view in the state where a seat was omitted. (A) is a perspective view of a state where a seat cushion and a backrest are separated, and (B) is a perspective view of a state where a seat inner shell is separated. (A) is an isolated perspective view, (B) is a perspective view seen from below. It is a front view in the state which omitted a seat. (A) is a side view of the backrest, (B) is a plan view of the backrest. (A) is a perspective view showing a mounting structure of a lower end of a back plate, and (B) is an exploded perspective view showing a part of a mounting procedure of the back plate. (A) is a sectional view taken along the line IX-IX of FIG. 3, and (B) is an exploded perspective view showing a connection structure of a lower portion of a backrest. (A) and (B) are perspective views each showing a connection structure of a back plate to a back support. (A) is a perspective view showing a connection structure of a back plate to a back support, (B) is a partial perspective view of the back support, and (C) is a perspective view of a bracket. It is a longitudinal side view centering on the connection part of a back board and a back support, and also shows a back board in order to show an attachment procedure.

(1). Outline Next, an embodiment of the present invention will be described. The present invention is applied to a swivel chair used in an office or the like. First, an outline of a chair will be described with reference to FIGS. The chair includes a seat 1, a backrest 2, and a leg device 3. The leg device 3 includes five branch rods and a leg support 4 (gas cylinder), and a caster is provided at the tip of each branch rod.

  The backrest 2 is composed of only a back plate made of synthetic resin. Therefore, in this embodiment, the backrest 2 and the backboard are the same, and the wording of the backrest 2 will be used below as the meaning of the backboard. The backrest 2 can have a structure in which a back cushion is stretched on the front surface of the backboard, or a structure in which the backboard (back inner shell) is covered with a cloth for makeup. In this case, the concept of the backrest 2 is different from that of the backboard.

  As shown in FIG. 5, a base 5 having a rectangular shape in a plan view is fitted to the upper end of the leg support 4. On the other hand, for example, as shown in FIG. 4, the seat 1 has a structure in which a seat cushion 7 is stretched over a seat inner shell 6 made of synthetic resin and covered with a skin material, and the seat inner shell 6 is a seat outer shell (made of synthetic resin). (Seat receiving member) 8. As can be understood from FIG. 5B, the seat outer shell 8 is formed with a boss portion 8a that is open downward and is square in bottom view, and the boss portion 8a and the base 5 are fitted to each other and are screwed together. It is fixed.

  A push valve (not shown) for releasing the lock projects from the upper end of the leg support 4, and the push valve is pushed down by, for example, a forward-tilt-rotating pressing member 9 shown in FIG. 3. The pressing member 9 is rotatably connected to the seat outer shell 8. A relay link 11 is attached to a portion of the seat outer shell 8 before the pressing member 9 so as to be horizontally rotatable. The relay link 11 and the pressing member 9 are provided with balls (not shown) at both ends. Connected by a wire 10.

  As shown in FIG. 3, one end of an operation belt 13 as an example of an operation tool is locked to the relay link 11. The other end 13a of the operation belt 13 extends downward from a slit hole 14 (see FIGS. (A) and (B)) formed in the seat outer shell 8, and when the other end 13a of the operation belt 13 is pulled, a relay link is provided. 11 rotates horizontally to rotate the pressing member 9 downward. As a result, the push valve of the leg support is pushed down, and the lock of the gas cylinder is released.

  A front-facing portion 15 is integrally formed at the lower end of the backrest 2, while a left-right longitudinal reinforcing plate (reinforcing bracket) 16 made of a metal plate such as a steel plate is fixed to a rear upper surface of the seat outer shell 8. The front portion 15 of the backrest 2 is held immovably upward by left and right bearing portions 17 formed on the reinforcing plate 16. The backrest 2 can be slightly inclined backward with respect to the seat outer shell 8 and the reinforcing plate 16.

  At the rear end of the seat outer shell 8, a vertically long back support 18 located behind the backrest 2 is formed integrally. At the upper end of the back support 18, a left and right middle part of the backrest 2 is provided. The upper and lower mid-height portions are connected. The backrest 2 is also connected to the back column 18 so as to be able to tilt slightly backward. Note that the back column 18 has a front lower portion 18a connected to the seat outer shell 8, and rises upward from the rear end of the lower portion 18a. As shown in FIG. 1A, the chair can be provided with an armrest 19 as an optional item.

(2). Structure of the backrest As shown in FIG. 6, for example, in front view, the left and right side edges of the backrest 2 are swollen to the left and right by the portion located near the waist of the seated person. Therefore, a portion of the backrest 2 except for the forward facing portion 15 (an indispensable portion that receives a seated person's body pressure) is substantially hexagonal in a front view, and each apex has a roundness.

  Further, as shown in FIG. 7A, for example, the backrest 2 bends in a forward convex shape so that a portion (lumbar support portion) for supporting the lumbar region of the occupant is located at the forefront in a side view. In FIG. 7B, the left and right sides are obliquely forward and are recessed forward as clearly shown in FIG. 7B.

  Accordingly, the backrest 2 is divided into upper and lower areas with a left and right long ridge line (lumbar support portion) positioned substantially at the height of the waist of the seated person, and the upper and lower areas are respectively left and right inclined areas and inclined areas. It is divided into a center area located between. Accordingly, the backrest 2 is divided into six areas: an upper center area 21 and left and right upper side areas 22, and a lower center area 23 and left and right lower side areas 24.

  In addition, the upper and lower center areas 21 and 23 are integrally connected via a center horizontal hinge 25, the upper and lower side areas 22 and 24 are integrally connected via a side horizontal hinge 26, and the upper center area 21 and the upper side area 22 are connected to each other. The lower center area 23 and the lower side area 24 are integrally connected via a lower vertically long hinge part 28. The left and right upper vertical hinge portions 27 are inclined so as to increase the interval upward, and the left and right lower vertical hinge portions 28 are inclined so as to increase the interval downward. Therefore, the upper center area 21 has a trapezoidal shape spreading upward, and the lower center area 23 has a trapezoidal shape spreading downward.

  As clearly shown in FIG. 7B, each hinge portion 25, 26, 27, 28 is formed by thinning and has a width of about 50 to 60 mm. Therefore, each of the hinge portions 25, 26, 27, 28 has a curved shape itself. The width of the side horizontally long hinge portion 26 is slightly widened toward the left and right sides. The other hinge portions 25, 27, 28 have substantially the same width.

  As clearly shown in FIG. 7A, the lower end of the upper center area 21 of the backrest 2 is connected to the back support 18. In the backrest 2, a large number of circular small holes 29 are formed aligned in the oblique lattice direction. Each of the small holes 29 is basically a through hole that is opened forward and backward, but there is a portion that is attached to the back column 18 and is opened only at the front without penetrating (see FIG. 12).

  A large number of small holes 29 are also formed in each of the hinge portions 25, 26, 27, 28. The hinge portions 25, 26, 27, and 28 are easily deformed due to the presence of the large number of small holes 29. The inside diameter of the small hole 29 is several mm, and the pitch in the oblique direction is about twice the inside diameter. However, this is an example, and the inside diameter, the pitch, and the arrangement mode can be arbitrarily set. A plurality of types of small holes 29 having different inner diameters may be formed.

(3). Significance of the backrest When a seated person, for example, performs work, his / her waist can be applied to the center horizontally long hinge portion 25 to maintain the posture in which the upper body is upright for a long time. Therefore, it is possible to keep taking a posture with less burden on the body. In this case, since the center horizontally long hinge portion 25 is gently curved in a longitudinal side view, the occupant's contact with the waist is soft and comfortable.

  When the center horizontal hinge portion 25 is pressed with a certain strength by the body pressure of the occupant's waist, the center horizontal hinge portion 25 is deformed so as to expand vertically, and the left and right side areas 22 and 24 are pulled inward. As a result, the backrest 2 has a tendency to contract inward. In other words, the backrest 2 is deformed so as to surround the body of the seated person. Therefore, the stability of the posture of the occupant's body is enhanced.

  Although the backrest 2 of the present embodiment does not lock, it can be slightly tilted backward because there is some clearance at the connection with the back column 18. When the seated person leans on the backrest 2 while stretching the body, the point of application of the body pressure is located above the upper end of the back column 18, and as shown by an arrow 31 in FIG. 21 and 22 may lean backward slightly.

  In this case, when the upper areas 21 and 22 are inclined backward, the backrest 2 tends to spread as a whole, so that the horizontally long hinge portions 25 and 26 are easily bent. Further, since the horizontally long hinge portions 25 and 26 are originally band-shaped and are easily bent and deformed in the front-rear direction, the rear tilt of the upper areas 21 and 22 is further facilitated.

  Further, since the lower end of the backrest 2 is connected to the reinforcing plate 16, when the body pressure of the occupant acts on a portion above the horizontally long hinge portions 25, 26, the horizontally long hinge portions 25, 25 are viewed from a vertical side view. Tend to reduce the degree of bending. Then, the left and right areas 22 and 24 tend to spread outward.

  That is, when the body pressure of the occupant acts on the portions above the horizontally long hinge portions 25 and 26, the backrest 2 tends to deform into a flat state. Therefore, a relaxed state can be obtained without feeling cramped. In addition, since the backrest 2 is elastically deformed, it is possible to maintain a cushioning property against the movement of the occupant leaning backward. Also in this aspect, comfort can be improved.

  The seated person leans on the backrest 2 with the body tilted right or left, or the seated person sits on the seat 1 with the body leaned right or left, and leans on the backrest 2 in that state. Then, the body pressure strongly acts on the center horizontal hinge portion 25, but in the present embodiment, since the vertical hinge portions 27 and 28 are wide and easily deformed, as shown by an arrow 32 in FIG. 22 and 24 rotate together rearward. Therefore, even if the occupant leans backward and leans, it is excellent in the function of following the body and deforming, and the hit of the occupant's body is soft. Therefore, comfort can be improved.

  In many cases, the seated person leans on the backrest 2 in a state where the upper body is tilted right or left (or in a state where the upper body is twisted). In this case, an arrow 33 shown in FIG. 3 and FIG. Thus, it acts strongly on the upper side area 22 on one side. Then, in the present embodiment, as shown by the dashed line in FIG. 7B, the upper side area 22 can be largely inclined backward (rotated) backward. Also in this respect, the function of deforming the backrest 2 following the movement of the body is excellent.

  As described above, the backrest 2 of the present embodiment can be elastically deformed while securing high followability to the occupant's body while being a single product made of synthetic resin. Therefore, while having a simple structure, it is excellent in the fitting property and cushioning property to the body of the seated person, and high quality can be secured.

(4) Connection structure between the backrest and the outer seat shell Next, the connection structure between the backrest 2 and the outer seat shell 8 will be described mainly with reference to FIGS. As described above, the left and right longitudinal reinforcing plates 16 are fixed to the rear upper surface of the seat outer shell 8 with screws (not shown), and the bearing portions 17 are formed on the reinforcing plates 16.

  For example, as shown in FIG. 9 (B), the bearing portion 17 of the reinforcing plate 16 is formed by cutting and raising, and has an upright portion and a horizontal piece facing rearward from the upper end thereof, and has an inverted L-shaped side surface. It is in the form. On the other hand, as shown in FIGS. 8 (B) and 9 (A), left and right longitudinal first boss portions 35 which engage with the bearing portions 17 from below are integrally formed at the left and right end portions of the front portion 15 of the backrest 2. Is formed.

  The rear surface of the seat outer shell 8 is defined by a rear wall 37 and rests on the rear wall 37 of the front portion 15 of the backrest 2. A relief space 36 is formed between the rear wall 37 and the bearing 17, and the first boss 35 enters the relief recess, and the lower space 18 a of the backrest 2 includes the relief space 36. A second boss portion (step portion) step portion 38 is formed to enter and engage with the front surface of the rear wall 37.

  The first boss portion 35 and the second boss portion 38 constitute a movable engagement portion, and the rear wall 37 of the seat outer shell 8 and the bearing portion 17 of the reinforcing plate 16 constitute a fixed engagement portion. Note that the lower end of the second boss 38 and the lower end of the first boss 35 may be flush with each other.

  The lower end of the backrest 2 is held immovably backward by the rear second boss 38 engaging (abutting) with the front surface of the rear wall 37, and the first boss 35 is attached to the bearing 17 from below and from behind. By engaging (hitting), it is held immovable upward and immovable forward. The first boss portion 35 of the backrest 2 is formed so as to step down from the front end of the forward facing portion 15 and has an oblong shape in the front-rear direction when viewed from the side.

  The rear wall 37 of the seat outer shell 8 is located closer to the rear end of the seat 1 than the rear end. Therefore, a rear portion of the seat inner shell 6 located behind the seat outer shell 8 is an overhang portion 6a. The overhang portion 6a can be tilted backward by the body pressure of the seated person by the hinge portion 6b.

  When attaching the backrest 2, first, the backrest 2 is placed in a non-use position in which the backrest 2 is largely tilted toward the front side so that the front portion 15 thereof is in the downward position as shown in FIG. The backrest 2 is set in a predetermined posture, and then the upper part of the backrest 2 is connected to the upper end of the back column 18. Therefore, the lower part of the backrest 2 can be connected in one touch without using a fastener such as a screw. Therefore, the labor for assembling the chair can be reduced.

  As shown in FIG. 9 (A), left and right ribs 36a are formed at the location of the relief space 36, and the upper surface of the rib 36a is a curved surface (guide surface) 36b that is concave upward when viewed from the side. I have. The left and right ribs 36a are arranged so as to overlap the first boss 35 in plan view. The front portion 15 of the backrest 2 is formed with a second boss (step) step portion 38 which enters the escape space 36 and engages with the front surface of the rear wall 37.

  In mounting the backrest 2, in raising the backrest 2 from the non-use position in which the backrest 2 is tilted forward to the use position (tilt the backrest 2), the first boss 35 contacts the curved surface 36 b of the rib 36 a, and the fulcrum is used as a fulcrum. Since the backrest 2 can be rotated in this manner, the backrest 2 can be automatically held in a predetermined posture. Therefore, it becomes more reliable to assemble the backrest 2 quickly and accurately.

  The reinforcing plate 16 is also used for attaching an armrest 19 shown in FIG. As shown in FIGS. 5 (A) and 9 (B), a flat, triangular fixed seat 39a is formed in the rear portion of the seat outer shell 8 below the left and right ends of the reinforcing plate 16, while the reinforcing plate 16 is reinforced. At both left and right ends of the plate 16, overlapping portions 39b are formed so as to overlap the fixing seat 39a from above, and through holes 40a and 40b through which the shaft portion of the screw is inserted from above are formed in the fixing seat 39a and the overlapping portion 39b. are doing. The screw is screwed into a nut provided on the base of the armrest 19.

  The overlapping portion 39b of the reinforcing plate 16 is fixed to a fixed seat 39a of the seat outer shell 8 by a screw (not shown). As shown in FIGS. 8 (A) and 9 (B), screw holes 16a for fixing the reinforcing plate 16 are also provided in portions of the reinforcing plate 16 near the left and right intermediate portions.

(5). Connection Structure between Backrest and Back Prop Next, a connection structure between the backrest 2 and the back support 18 will be described with reference to FIGS. As shown in each of FIGS. 10 to 12, a bracket portion 43 having left and right side walls 41 and an eaves plate 42 connected to the left and right side walls 41 is formed in a lower left and right middle part of the upper center area 21 of the backrest 2. In addition, a joint member 44 is connected to the inside of the bracket portion 43 with left and right longitudinal pins 45, and the joint member 44 is connected to the upper end of the back column 18.

  A thick-walled shaft support portion 41 a is formed at the upper portion of the left and right side walls 41 constituting the bracket portion 43, and the upper portion of the joint member 44 is connected to the shaft support portion 41 a by a pin 45. Below the eaves plate 42 in the bracket portion 43, a large number of support pieces 47 for supporting the pins 45 from obliquely above are formed side by side in the left-right direction.

  The joint member 44 is made of a synthetic resin and includes a back plate (substrate) 48 located on the side of the back column 18, left and right side plates 49, an upper surface plate 50 and a lower surface plate 51. It has a box-like shape that opens toward the bracket portion 43 of the backrest 2, and the upper portion of the side plate 49 extends upward to form a bearing portion 49a, through which the pin 45 is inserted. The left and right ends of the pin 45 are exposed portions protruding outside the bracket 43. Further, an upward rib 50a is formed at the tip of the upper surface plate 50.

  The back support column 18 has a gutter-like form by the substrate and the front side plates 18b provided on both right and left ends thereof, and has a holding portion (pocket portion) 52 having an enlarged front projection size of the side plate 18b at an upper end portion. Is formed, and the bracket portion 43 and the joint member 44 of the backrest 2 enter the holding portion 52. The upper surface of the holding portion 52 is closed by a top plate.

  Left and right inner walls 53 surrounding the bracket 43 from both left and right sides are formed inside the holding portion 52, and a bearing groove 54 into which the exposed portion 45 a of the pin 45 is fitted from above is inserted into the upper portion of the inner wall 53. Is formed. The lower end of the inner wall 53 is connected to the side plate 18b via a rib, so that the bracket portion 43 of the backrest 2 enters a space formed between the inner wall 53 and the side plate 18b.

  As shown in FIG. 11A, the bearing groove 54 is slightly inclined forward with respect to the vertical line. In addition, an engaging claw 55 located at a left and right intermediate portion and positioning projections 56 located on both left and right sides of the holding portion 52 of the back column 18 project forward.

  On the other hand, the back plate 48 of the joint member 44 has a rectangular engagement boss 57 having an engagement hole into which the engagement claw 55 is fitted and engaged, and a rectangular cylindrical positioning boss having the positioning projection 56 fitted therein. 58 are formed. A downward hook portion is formed at the tip of the engaging claw 55, and the engaging claw 55 is hooked on and engaged with the tip of the engaging boss portion 57, so that the backrest 2 is connected to the back support via the joint member 44. 18 and cannot be detached. Further, the left and right positioning projections 56 are held so that the positioning boss portion 58 does not rattle vertically and horizontally.

  As a mounting procedure of the backrest 2, first, the joint member 44 is connected to the bracket portion 43 of the backrest 2 with a pin 45 in advance. Then, while the lower end of the backrest 2 is connected to the rear end of the seat outer shell 8 by the procedure described above, the backrest 2 is raised to the use posture, so that the exposed portion 45 a of the pin 45 is moved to the bearing groove 54 of the back column 18. And fit it from above. Next, the joint member 44 is pressed against the holding portion 52 of the back column 18 to fit the engaging boss 57 into the engaging claw 55 and the positioning boss 58 into the positioning protrusion 56.

  The fitting of the engaging boss 57 to the engaging claw 55 and the fitting of the positioning boss 58 to the projection 56 are performed by rotating the joint member 44 backward with the pin 45 as a fulcrum.

  As the engagement boss 57 is fitted into the engagement claw 55, the engagement claw 55 rotates once to escape and then returns against the elasticity, so that the hook is hooked on the engagement boss 57. In this state, the joint member 44 and the backrest 2 are held so as not to be able to be detached vertically and horizontally with respect to the back column 18. As a result, the exposed portion 45 a of the pin 45 is held in a state fitted in the bearing groove 54. Therefore, the attachment of the backrest 2 can be performed in one touch.

  When removing the backrest 2, the engagement claw 55 is rotated upward with a fingertip or a tool to release the engagement of the engagement claw 55 with the engagement boss portion 57, and then the joint member 44 is turned forward. By moving it, the fitting between the positioning protrusion 56 and the positioning boss portion 58 is released, and then, the upper part of the backrest 2 is pulled upward, and the pin 45 is pulled out of the bearing groove 54, and the procedure is taken. .

  For example, as shown in FIGS. 11C and 12, a number of groups of receiving ribs 59, which strike the pins 45 from obliquely rearward, are provided side by side in the upper end of the back support 18. To be precise, the front surface of the receiving rib 59 is in a forwardly inclined posture. Therefore, when a back external force is applied to the backrest 2 by the body pressure of the occupant, the pins 45 tend to be pressed downward by the receiving ribs 59, and receive the external force pushed deep into the bearing grooves 54. Therefore, there is no problem that the backrest 2 comes off the back support 18 due to the body pressure of the seated person.

  By the way, as can be understood from FIG. 11A, the front surface of the receiving rib 59 is almost parallel to the opening direction of the bearing groove 54, and therefore, a perpendicular line perpendicular to the front surface of the receiving rib 59 is It is orthogonal to the opening direction.

  Then, when the body pressure of the occupant acts below the pins 45, the upper portion of the backrest 2 tends to rotate toward the front, and the pins 45 rotate clockwise in FIG. While it tends to slip out of the bearing groove 54 while exhibiting a tendency, if the receiving rib 59 in the forwardly inclined posture is provided, the rotation of the pin 45 in the clockwise direction is suppressed by friction, and the pressing force against the backrest 2 is reduced. Even if there is an upward component force, the upward component force is suppressed by the receiving rib 59, and the upward movement is prevented. Therefore, the removal of the pin 45 can be reliably prevented.

  When the seated person's body pressure acts above the pin 45, the upper part of the backrest 2 tends to lean backward with the pin 45 as a fulcrum. In this case, the backward pressing force due to the seated person's body pressure is downward. The pin 45 receives an external force such that it is pushed deep into the bearing groove 54 by the guide action of the bearing groove 54 and the guide receiving rib 59. Therefore, the pin 45 does not come out of the bearing groove 54 at all.

  Although the receiving rib 59 has such an excellent function, if the pin 45 hits the receiving rib 59 repeatedly over a long period of time, the receiving rib 59 may be worn and resin powder may be generated. If the resin powder falls on the floor or falls on the front portion 15 of the backrest 2 and is exposed to the eyes, the appearance may be impaired.

  In this regard, in the present embodiment, as shown in FIG. 12, the upper surface plate 50 of the joint member 44 is positioned just below the ribs 59 and the pins 45 to form upward ribs 50a at the end of the upper surface plate 50. Thus, the upper surface plate 50 functions as a receiving member for the resin powder. Therefore, it is possible to prevent the appearance from being deteriorated due to the falling of the resin powder without complicating the structure.

  The lower end of the backrest 2 is connected to the seat outer shell 8 with a slight clearance, and at the connection with the back column 18, the lower end of the backrest 2 can slightly tilt back and forth with the pin 45 as a fulcrum. Therefore, the backrest 2 can slightly rotate in the front-rear direction.

  In the present embodiment, since the eaves plate 42 provided on the backrest 2 enters the inside of the holding portion 52, the upward movement of the backrest 2 is also prevented by the eaves plate 42 hitting the top plate of the holding portion 52. ing. Therefore, the stability of the backrest 2 is high. Further, since the upper surface of the eaves plate 42 is gently curved in a side view, the backrest 2 is allowed to rotate about the pin 45. Therefore, the rotation of the backrest 2 following the movement of the seated person can be smoothly performed.

(6). Others Although the embodiments of the present invention have been described above, the present invention can be variously embodied. For example, it is also possible to connect the joint member to the back support with a pin and connect the joint member to the backrest with the engagement means. The engagement means is not limited to the combination of the engagement claw with the box-shaped engagement boss as in the embodiment, but may be a combination of an engagement claw and an engagement claw. A combination of an engagement piece having an engagement hole and an engagement protrusion fitted into the engagement hole can also be adopted. It is also possible to form a plurality of engagement means.

  As a means for positioning the joint member and the holding portion, a combination of a positioning protrusion and a positioning hole, or surrounding the outer periphery of the joint member with a rib can also be adopted. In the embodiment, the joint member is suspended by a pin, but it is also possible to arrange the joint member in a state of being superimposed on the back surface of the backrest or the front surface of the back column. In this case, the engaging portions can be engaged with each other by pressing the backrest against the back support.

  In the embodiment, the backrest is constituted only by the back plate. However, it is also possible to adopt a structure in which a back cushion is stretched at least on the front surface, or to cover the front and rear surfaces with a bag-like skin material such as cloth. It can also be applied to the back of a structure in which a mesh material is stretched on a frame. Further, the present invention can be applied to a rocking chair in which the backrest and the back strut are inclined backward against the spring means.

  Further, in the case where the backrest has a configuration in which a plurality of areas are connected by a hinge portion as in the embodiment, similarly to Patent Literature 1, the back plate is a three-stage type including an upper area, a middle area, and a lower area. And it is also possible to divide the level into a center area and left and right side areas. In this case, it is preferable that the left and right vertically long hinge portions connecting the center area and the side area in the upper stage have a posture in which the interval between them is narrowed upward. The back strut may be configured as a separate member from the seat outer shell.

  The lower end of the backrest (back plate) can be connected to the rear end of the seat or the lower end of the back column (a portion extending in the front-rear direction). Alternatively, it is also possible to connect to a seat receiving member other than the seat outer shell (for example, a base or an intermediate metal fitting arranged between the base and the seat outer shell).

  The present invention can also be applied to a rocking chair in which the backrest tilts backward against the spring means. The leg device does not need to be a gas cylinder type, and can be applied to a non-rotating chair such as a four-legged type.

  The present invention can be embodied in a chair. Therefore, it can be used industrially.

1 seat 2 backrest 18 back support 18a side plate 41 bracket part 42 eaves piece 45 pin 44 joint member 50 top plate (powder receiving part)
52 Holding portion 43 Inner wall provided in holding portion 54 Bearing groove 55 Engagement claw as an example of engagement portion 56 Positioning protrusion 57 Engagement boss portion 58 Positioning boss portion 59 Receiving rib

Claims (5)

It has a backrest and a back strut arranged behind the backrest, wherein the backrest is connected to the back strut via left and right longitudinal pins,
A left and right bracket portion is provided on one of the backrest and the back support, and a joint member is relatively rotatably connected to the left and right bracket portions via the pin.
On the other of the backrest and the back strut, a holding portion having left and right side plates on which the pin is held so that the pin cannot be left and right is formed, and the holding portion has a bearing groove into which the pin is dropped. Has formed,
Further, an engagement portion is formed on the holding portion and the joint member, the engagement portion engaging in the front-rear direction and holding the pin from the bearing groove so as not to come off.
Chair. Left and right brackets project from the back of the backrest, and the joint members are connected to the brackets by the pins.
The back strut has a U-shape in cross section having left and right side plates facing the backrest, the holding portion is formed at an upper end portion, and the engaging portion is formed between the back strut and a joint member. Forming a
The chair according to claim 1. The engagement portion includes an engagement claw having a hook at a tip thereof, and a cylindrical engagement boss portion into which the engagement claw is fitted.
The chair according to claim 1. A receiving rib having a forwardly inclined posture that supports the pin pressed backward by the body pressure of the seated person is formed on the holding portion,
The chair according to claim 2. The coupling member has a top plate located below the receiving rib, and an upward piece is provided at a front end of the top plate.
The chair according to claim 4.

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