JP2013106727A - Chair with backrest - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chair with a backrest in which a back outer shell is rigidly mounted to a back frame without increasing the size of the back outer shell.SOLUTION: The back outer shell 12 is made of a resin, and has side ribs 23 and inner ribs 24 positioned on the inside of the side ribs. The back rest 5 is disposed so that the back side thereof abuts on the side ribs 23. A wide back supporting portion 11 is raised from the rear end of a back frame 8, and both right and left ends of the back supporting portion 11 are provided with back posts 13. An inner shell 16 has a space enclosed by the side ribs 23 and the inner ribs 24, and is formed with pocket portions 25 into which the upper parts 13a of the back supports 13 are fitted. The pocket portion 25 is provided in a dead space of the back outer shell 12, so that the back outer shell 12 is mounted to the back frame 8 without increasing the size of the outer shell. The back inner shell 16 is non-disengageably held at the back frame 8 by engaging a lower stopper 29 and a corner engaging pawl 32 to the back frame 8.

Description

  The present invention relates to a chair having a backrest.

  In a rocking chair, a back outer shell is attached to a back frame that is connected to a base so as to freely tilt backward, and a backrest is attached to the back outer shell, or a backrest is attached to the back frame.

  As an example of attaching the backrest to the back frame, Patent Document 1 describes that in a chair in which a mesh material is attached to a back support having a frame structure with the backrest opening in the front and rear, protruding portions protrude from the left and right ends of the back frame. It is disclosed that the lower end portions of the left and right side members constituting the back support are fitted into the upright portion. Patent Document 2 discloses that a shell-like back plate is fitted into back support portions arranged on the left and right.

JP 2006-122461 A JP 2007-143961 A

  Both of the above publications are designed to fit the backrest components into the back strut, both of which have advantages such as easy assembly of the chair. On the other hand, as a structure for attaching the back outer shell to the back frame, screwing is also employed. However, when a fitting method as in Patent Document 2 is employed, there is an advantage that assembly can be easily performed.

  In that case, since the back outer shell also exhibits a cosmetic function of covering the backrest from behind, it is preferable that the back frame is not exposed to the outside as much as possible. Further, since a large back load acts on the back outer shell, the connecting portion between the back outer shell and the back frame needs to exhibit a high support function.

  The present invention has been made in view of such a current situation, and an object thereof is to ensure high support strength while ensuring ease of attachment as in Patent Document 2.

  The chair of the present invention (invention of claim 1) has a back outer shell attached to a back strut disposed on the back side of the seat, and the backrest is attached to only the back outer shell or the back outer shell and the back strut. In this configuration, a group of ribs protruding forward is provided on the front surface of the back outer shell, and the back strut is disposed so as to fit in a space surrounded by the ribs, and the back outer shell On the front surface of the shell, a pocket portion having a downward opening is formed in which the upper portion of the back column is fitted from below.

  The present invention can be developed in various ways. Examples of this are specified in claims 2 and 3. Of these, the invention according to claim 2 is the invention according to claim 1, wherein a base on which an upper end of a leg support is fitted is disposed below the seat, and a back frame connected to the base to be freely tilted backward is provided. At the rear end, a substantially plate-like back support portion extending in the left-right direction rises, and the back strut rises from the left and right sides of the back support portion.

  Further, according to the present invention, the front engaging portion formed at the back support portion and the left and right rear end portions of the back frame at the left and right intermediate portions and the left and right end portions of the lower portion of the back outer shell. A rear engagement portion is formed, and the back engagement portion of the backrest is elastically deformed by pressing the lower portion of the backrest toward the front in a state where the upper end portion of the back column is fitted in the pocket portion. It engages with the front engaging portion of the back outer shell.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, an upper and lower longitudinal groove that opens forward is formed on the front surface of the back support portion.

  In this invention, since the group of ribs is formed in the front surface of the back outer shell, the back outer shell can ensure extremely high strength while being thinned as a whole. And since the backrest is located in front of the rib, the space surrounded by the rib is dead space, but the back strut is placed in the space that is dead space, so the back outer shell can be enlarged or It can be connected to the back column without reducing the strength.

  Moreover, since the pocket part also exerts the reinforcing effect of the back outer shell, it can contribute to an increase in strength. Further, since the back strut has a portion exposed on the front side of the back outer shell, it can be used for mounting the armrest device as in the embodiment.

  If the structure of Claim 2 is employ | adopted, a backrest will be firmly attached to a back frame by very simple operation of inserting a pocket part in a back support | pillar, and pressing a lower part against a back frame. Therefore, the efficiency of assembling the chair can be significantly improved.

  Since the load of the back outer shell acts on the back column from behind, it is preferable that the back column has a certain lateral width in order to prevent stress from concentrating on a narrow part of the back outer shell. That is, the contact surface between the back column and the back outer shell preferably has a certain size. On the other hand, the back frame is preferably a metal die-cast product or a resin molded product, but if the back column has a certain amount of lateral width, it may become stronger than necessary and the amount of material used It may increase and become uneconomical.

  On the other hand, when a longitudinal groove is formed on the front surface of the back column as in claim 3 of the present application, there is an advantage that the amount of material used can be reduced while ensuring the necessary strength. Further, as shown in the embodiment, the longitudinal groove can be used for attaching the backrest.

BRIEF DESCRIPTION OF THE DRAWINGS It is an external view of the chair which concerns on embodiment, (A) The perspective view seen from this front, (B) is the perspective view seen from back, (C) is a side view. (A) is the isolation | separation perspective view of the main components of a chair, (B) is the fragmentary perspective view of a back frame and a back outer shell. It is a separation perspective view of a back frame and a back outer shell. (A) is a separated perspective view of the back frame and the back outer shell, (B) is a partial vertical side view of the connecting portion between the back frame and the back outer shell, and (C) is a portion of the back corner of the back frame. A perspective view and (D) are partial perspective views of a back outer shell. (A) (B) is a perspective view which shows the attachment structure of an armrest apparatus. It is the figure which arranged the back support and back inner shell which consist of a back outer shell and a back frame side by side (the back inner shell is turned over and displayed). It is a separation perspective view of a back inner shell and a back support. It is a separation perspective view of a back inner shell and a back support. (A) (B) is a partial perspective view of a back inner shell, (C) is a partial perspective view of a back outer shell. (A) (C) is a partial perspective view of a back outer shell, (B) (D) is a partial perspective view of a back inner shell. (A) is a separated perspective view of the catch member and the back outer shell, (B) is a perspective view of the catch member attached to the back inner shell, and (C) is a separated perspective view of the back inner shell and the catch member. (D) is a perspective view of a catch member. It is sectional drawing which cut | disconnected the substantially upper half part of the backrest by the YY line of FIG. It is sectional drawing which cut | disconnected the upper half part of the backrest by the YY line | wire of FIG.

  Next, an embodiment of the present invention will be described with reference to the drawings. In the following description, the words “front and rear” and “left and right” are used to specify the direction, but the words on the front and rear and right and left are based on the person who is seated. The front view direction is the direction facing the seated person, and therefore the left and right in the front view are opposite to the left and right viewed from the seated person.

(1). Outline of Chair First, an outline of a chair will be described mainly with reference to FIGS. This embodiment is applied to a swivel chair often used for office work or the like. As shown in FIG. It has a base 3, a seat 4 arranged on the base 3, and a backrest 5 on which a seated person can lean.

  An intermediate member (seat receiving member) 6 shown in FIG. 1B is disposed on the base 3, and a resin seat outer shell 7 is attached to the intermediate member 6. The seat 4 includes a resin seat inner shell (seat plate) and a seat cushion material arranged on the upper surface thereof, but since there is no direct relationship with the present application, the description thereof is omitted.

  As shown in FIG. 2, a back frame 8 is connected to the base 3 so as to be able to tilt backward, and a back outer shell 9 is attached to the back frame 8. The back frame 8 includes left and right side arms 9 extending substantially in the front-rear direction, left and right laterally long rear portions 10 integrally connected to the rear end thereof, and a back support portion 11 rising from the rear end of the rear portion 10. The back outer shell 12 is attached to the back support 11.

  The back strut portion 11 stands up in a generally plate-like state, and the back struts 13 projecting upward are integrally provided on the left and right sides thereof (the back strut 13 is also a part of the back support portion 11, and therefore The back support portion 11 has an upwardly-opening U-shape having a base portion and left and right back struts 13). A John Into bar 14 is integrally connected to the middle part of the front and rear sides of the left and right side arms 9. For this reason, the back frame 8 has a sturdy structure.

  The chair according to the present embodiment is a synchro type in which the seat is tilted backward while rocking, and the connecting shaft 15 connected to the intermediate member 6 is integrally formed or welded to the joint bar 14. . In FIG. 3A, a retaining cap fitted to the intermediate member 6 is fitted to the right end of the shaft 15.

  The back frame 8 is made of an engineering plastic such as a glass-based polyamide resin, but a metal die-cast product such as aluminum or a sheet metal product can also be used. The back outer shell 12 is a molded product made of a resin such as polypropylene. As shown in FIG. 1 (B), the upper portion of the back outer shell 12 is a rearward projecting portion 12a that protrudes behind the backrest 5 while curving in a side view. It is open.

  As shown in FIG. 1A, the backrest 5 includes a resin back inner shell (back plate) 16 and a cushion 17 stretched on the front surface thereof. The cushion 17 is covered with a skin material 18 such as a cloth. It has been broken. The skin material 18 wraps around the back inner shell 16 but does not cover the entire back surface of the back inner shell 16. And in this embodiment, the back support is comprised by the back support part 11 and the back outer shell 12 of the back frame 8, and the backrest 5 is attached to this back support by changing height in two steps. This point will be described next.

(2). Attachment Structure of Back Frame and Back Outer Shell First, the attachment structure of the back outer shell 12 to the back frame 8 will be described mainly with reference to FIGS. As shown in FIG. 4A, the back column 13 has a substantially prismatic appearance, and a vertical groove 20 extending to the lower end of the back support 11 is formed on the front surface of the back column 13. In addition, a block portion 21 that protrudes outward in the left-right direction is integrally formed at the upper end of the back column 13. An opening groove 22 is formed upward between the upper end portion of the back column 13 and the block portion 21.

  On the other hand, for example, as shown in FIG. 3, vertical ribs 23 are formed on the left and right sides of the back outer shell 12, and vertical ribs 24 are formed inside the side ribs 23. Therefore, the space between the side rib 23 and the middle rib 24 is a space opened forward. And the pocket part 25 opened downward on the outer side of the inner rib 24 is formed, and the pocket part 25 is fitted to the upper end part 13a of the back column 13 from above. As a result, the back outer shell 12 is held so as not to move left and right with respect to the upper end portion 13 a of the back column 13 so that it cannot move back and forth.

  The block portion 21 is fitted in the space between the pocket portion 25 and the side rib 23. Further, the outer side plate 25 a of the pocket portion 25 is fitted in the upward opening groove 22 between the back column 13 and the block portion 21. The back outer shell 12 is molded by a mold apparatus mainly composed of a first mold for molding the front surface and a second mold for molding the back surface side, but the pocket portion 25 is formed in the first mold. Molded by the attached slide mold. And since the back outer shell 12 is curved in a longitudinal side view so that the lower part of the pocket portion is located at the forefront, the slide mold can be easily slidably mounted on the first mold.

  The side ribs 23 are provided at portions located on the inner side by a certain amount from the side end of the back outer shell 12. For example, as shown in FIG. 2A, left and right horizontally long upper ribs 26 are integrally connected to the upper ends of the left and right side ribs 23, while left and right horizontally long lower ribs 27 are connected to the lower ends of the left and right middle ribs 24. 27 and the upper rib 26 are connected by an inner rib rib 28 which is vertically long. The back inner shell 16 is in contact with the side rib 23 and the upper rib 26 (at least it is supported by the side rib 23, and a gap may be provided between the upper rib 26 and the back inner shell 16). .

  On the other hand, as shown in FIG. 12, there is a gap between the middle rib 24, the inner rib 28, the lower rib 27, and the back inner shell 16 when the person is not leaning against the backrest 5. Therefore, the back inner shell 16 can be somewhat deformed by the body pressure of the seated person. However, the left and right side portions and the upper portion of the back inner shell 16 are securely held by side ribs 23 provided on the back outer shell 12. Therefore, it does not bend greatly. For example, as shown in FIG. 2 (A), the back inner shell 16 is curved in a convex shape in a side view (or a longitudinal side view) so that the portion (lumbar support portion) that contacts the waist of the seated person is located in the foremost position. Following this, the back outer shell 12 is also curved in a forwardly convex shape in a side view.

  As shown in FIGS. 4 (A) and 4 (B), the bar portion 29b is connected to the front end of the left and right side plates 29a as a part of the rear engagement portion described in the claims at the left and right intermediate portions of the lower portion of the back outer shell 12. On the other hand, the back support portion 11 of the back frame 8 is provided with a lower stopper hole 30 into which the lower stopper 29 is fitted as a part of the front engagement portion. Forming.

  The bar portion 29b of the lower stopper 29 is formed with a claw piece 29c that protrudes obliquely rearward in a side view. On the other hand, the claw piece 29c is engaged with the upper inner surface of the stopper hole. A step portion 31 is formed. For this reason, the back outer shell 12 is held so that it cannot be pulled upward.

  Further, as shown in FIGS. 4A, 4C, and 4B, the left and right corner portions of the back outer shell 12 protrude obliquely upward in a side view as part of the rear engagement portion described in the claims. While the corner engaging claws 32 are provided, corner engaging holes 33 into which the corner engaging claws 32 are fitted are formed in the left and right rear corner portions of the back frame 8 as part of the front engaging portions described in the claims. Forming. The corner engagement holes 33 are formed with downward corner engagement protrusions 34 that are caught when the corner engagement claws 32 are elastically deformed and then returned.

  As shown by arrows 35 in FIGS. 4A, 4C, and 4B, the corner engaging claw 32 is fitted into the corner engaging hole 33 from behind. Similarly, the bar portion 29b of the lower stopper 29 is also fitted into the stopper hole 30 by pushing from the back to the front, and is hooked and engaged with the step portion 31 from the front by once elastically deforming and returning. The lower end of the back outer shell 12 and the rear end of the back frame 8 are smoothly continuous as if they were the same member, and the back support portion 11 and the back column 13 are not exposed to the outside. For this reason, a high cosmetic effect is exhibited.

  As described above, since the pocket portion 25 is disposed in the dead space between the side rib 23 and the middle rib 24, the back outer shell 12 does not increase in size. Also, due to the backrest load, a moment is generated in the backrest 5 such that the lower part is pushed forward centering on the upper end of the back column 13, but the lower part of the backrest 5 (lower part of the back inner shell 16) is supported in a wide range. Since it overlaps with the portion 11, the backrest 5 can be firmly supported by the back support portion 11.

  As shown in FIG. 5, the block portion 21 is formed with a recessed portion 36 that opens rearward. The upper end portion 38 of the fixed armrest 37 can be fitted into the recessed portion 36 and fixed with a screw 39. . A nut hole 41 into which the nut 40 is fitted is formed at the upper end portion 38 of the fixed armrest 37 so as to open at the tip thereof, and the screw 39 is inserted into the block portion 21 from the front and screwed into the nut 40. When the fixed armrest 37 is attached, the portion 23a outside the pocket portion 25 of the side ribs 23 of the back outer shell 12 is removed or folded inward (or folded back). . In order to make this removal or folding easy, the upper and lower slits 42 are formed in the side rib 23 (the base of the portion 23a to be removed or folded is also thinned).

(3). First engaging portion Next, a structure for attaching the backrest 5 to the back support composed of the back support portion 11 and the back outer shell 12 will be described mainly with reference to the drawings of FIG. 6 and subsequent drawings. The basic configuration of the back inner shell 16 will be described.

  The back inner shell 16 is a molded product made of a resin such as polypropylene, but a plurality of horizontally long slits 45 are formed in multiple stages in a substantially lower half portion. The back inner shell 16 has a group of horizontally long slits 45 and is continuous as a whole. Therefore, the lower half is roughly flexible. The back inner shell 16 is formed with a large number of horizontally long ribs 46 so as to have a certain degree of waist.

  In the present embodiment, as means for connecting the backrest 5 to the back support, the back surface of the back inner shell 16 is provided with a first front engaging portion 47 located on the upper side and on both left and right sides, and on the left and right sides. The second front engaging part 48 located on both sides, the pair of left and right third front engaging parts 49 located on the upper side and near the center, and the left and right outer sides of the third front engaging part 49 4th front part engaging part 40 is formed. On the other hand, the back outer shell 12 includes left and right first rear engagement portions 51 corresponding to the first front engagement portions 47, and a second rear engagement portion 52 corresponding to the second front engagement portions 48. A first rear engaging portion 53 corresponding to the third front engaging portion 49 and a fourth rear engaging portion 54 corresponding to the fourth front engaging portion 50 are provided.

  As shown in FIGS. 11B and 11C, the first front engaging portion 47 has left and right blade portions 47a and basically has a bottom view T, and the upper end of the blade portion 47a. The upper surface plate 47b is continuous. On the other hand, the first rear engaging portion 51 is formed of a catch member that is separate from the back outer shell 12. The first rear engagement portion 51 is a U-shaped basic form in which the left and right foot portions 51b protrude from the substrate 51a overlapping the back inner shell 16 to the front, and the first rear engagement portion 51 is formed at the front end of the left and right foot portions 51b. An inward flange 51c that holds the front engaging portion 47 from the front is formed. The upper and lower inner surfaces of the inward flange 51 c are inclined guide surfaces for guiding the first front engaging portion 47.

  A pair of upper and lower outward flanges 51 d are formed on the base 51 a of the first rear engagement portion 51. On the other hand, the back outer shell 12 is formed with two pairs of upper and lower catch portions 55 (two pairs each) holding the upper and lower outward flanges 51d of the first rear engagement portion 51 from the front. The catch portion 55 is disposed at a location close to the side rib 23. Therefore, the first rear engagement portion 51 is shifted to the left and right outside after being brought close to the back outer shell 12 in a state of being brought close to the middle rib 24 side. Is attached to the catch portion 55. Thereby, the 1st rear part engaging part 61 is attached to the back outer shell 12 so that forward movement is impossible.

  As shown in FIG. 11 (B), a horizontally long rib 56 is provided between the pair of catch portions 55, and a recess 56a is formed in the rib 56, while FIG. As shown, a rearward projection 51e that fits into the recess 56a is formed on the rear surface of the first rear engagement portion 51. Therefore, the first rear engagement portion 51 is held by the back outer shell 12 in a state where it is not easily dropped (the first rear engagement portion 51 is dropped even if the back outer shell 12 is turned over in the assembly process). Never to do.) For example, as shown in FIG. 7, a restricting plate 57 for positioning the first rear engagement portion 51 is provided on the left and right outer sides of the catch portion 55.

  Then, the upper part of the backrest 5 is overlapped and then shifted downward, so that the first rear engagement part 51 of the back inner shell 16 is fitted to the first rear engagement part 51 from above, whereby the upper part of the backrest 5 Is held so as not to move back and forth with respect to the back outer shell 12 so as not to move left and right. The height position of the backrest 5 can be regulated by the upper surface plate 47 b of the first front engaging portion 47 hitting the first rear engaging portion 51.

  In addition, since the back outer shell 12 has two sets of catch portions 55 in the vertical direction, the height of the backrest 5 can be increased in two steps by attaching the first rear engagement portion 51 to either the upper or lower catch portion 55. Can be changed. In FIG. 7 and FIG. 11 (A), the upper and lower two first rear engaging portions 51 are displayed, but only one of the upper and lower (two on the left and right) is actually used. Moreover, in FIG. 6, the 1st rear part engaging part 51 is not displayed. The first rear engagement portion 51 is a resin molded product.

(4). Second engagement portion As shown in FIG. 10, the second front portion engagement portion 48 of the back inner shell 16 protrudes backward, and the tip (rear end) faces inward in plan view. An engaging claw 48a is provided. On the other hand, the second rear engaging portion 52 is formed inside the vertical groove 20 of the back support portion 11 constituting the back frame 8, and accordingly, the first front engaging portion 48 is fitted in the vertical groove 20. It is held immovable from side to side. And the 2nd rear part engaging part 52 becomes an arrowhead-like engaging protrusion which is caught by the engaging claw 48a of the 1st front part engaging part 48 elastically deforming, and when it gets over, it cannot be returned to the near side. .

  In a state where the first front engagement portion 47 is fitted into the first rear engagement portion 51 (that is, in a normal use state), the second front engagement portion 48 overlaps with the second rear engagement portion 52. Therefore, when attaching the backrest 5, first, the first front engaging portion 47 is fitted into the first rear engaging portion 51 and then the backrest 5 is strongly attached to the back outer shell 12. When pressed, the engaging claw 48a of the second front engaging portion 48 is elastically deformed and then moved to the back of the second rear engaging portion 52, whereby the backrest 5 is held in a non-releasable manner.

  Further, as clearly shown in FIG. 10B, the second rear engagement portion 52 also has an upper portion 52a that prevents the second front engagement portion 48 from moving upward. Is held immovable upward. When removing the backrest 5, the lower end portion of the backrest 5 is pulled downward to shift the second front engagement portion 48 downward, and then the lower portion of the backrest 5 is moved forward. Since the back inner shell 16 has a large number of horizontally long slits 45, when the lower end is pulled, the lower half of the backrest extends and the second front engagement portion 48 moves downward. Can be canceled.

(5). Third Engagement Part / Fourth Engagement Part As shown in FIGS. 7 to 9, the third front part engagement part 49 has a lever shape extending downward, and is cut out on the back inner shell 16. It is in the state. A square engagement hole 59 is formed in the upper portion of the third front engagement portion 49 near the base, and the engagement hole 59 is fitted into the third rear engagement portion 53. The third engagement portion 53 is formed in a triangular shape in side view with the lower surface as the engagement surface.

  As shown in FIGS. 12 and 13, the third front engaging portion 49 is configured to extend rearwardly from the protruding portion 60 formed in the back inner shell 16, and the entirety thereof is behind the back inner shell 16. Is located. Then, when the backrest 5 is pressed against the back outer shell 12 after the first front engaging portion 47 is fitted into the first rear engaging portion 51, the engaging hole 59 of the third front engaging portion 49 becomes the third. It fits into the rear engagement portion 53. Thereby, the backrest 5 is firmly held so as not to move upward. That is, the third engagement portions 49 and 53 are most strongly responsible for the function of preventing the backrest 5 from moving upward.

  The third front engaging portion 49 is provided in an upper portion of the portion of the back inner shell 16 where the group of horizontally long slits 45 is provided. Therefore, as shown by the alternate long and short dash line in FIG. 12, when the back inner shell 16 releases the engagement between the second front engagement portion 48 and the second rear engagement portion 52 and then pulls the lower end forward, The lower half of the back inner shell 16 can be rolled forward. Thereby, a person can release the engagement of the third engaging portions 49 and 53 by placing the fingertip on the third front engaging portion 49 and pulling it forward.

  For example, as shown in FIG. 7, a hook-shaped auxiliary engagement claw 49 b facing upward in a side view is provided on the inner side of the third front engagement portion 49. An auxiliary locking portion 49c is provided above the auxiliary engagement claw 49b in the back inner shell 16 so that the auxiliary engagement claw 49b is hooked when the third front engagement portion 49 is pulled forward. Therefore, the third front engaging portion 49 can be held in the pulled state.

  Thus, since it has the auxiliary | assistant engagement nail | claw 49b and the auxiliary | assistant latching | locking part 49c, when removing the backrest 5, the 3rd front engagement part 49 on either side can be easily released | released one by one. Therefore, it is not necessary to hold the third front engagement portion 49 on one side, and the backrest 5 can be easily removed. You may provide the auxiliary | assistant latching | locking part 49c with respect to the one 3rd front engaging part 49 one by one. Moreover, when providing only in one side, you may provide in the outer side of the left-right direction.

  As shown in FIG. 9, the third front engaging portion 50 is formed in a substantially square shape and protrudes backward, and an engaging groove 54 protruding obliquely outward in plan view is formed at the tip thereof. doing. On the other hand, the 4th rear part engaging part 54 protrudes on the inner surface of the up-and-down longitudinal auxiliary rib 62 arrange | positioned on the outer side of the middle rib 24, and has comprised the nail | claw shape. The third front engaging portion 50 is inserted between the auxiliary rib 62 and the middle rib 24. Accordingly, the backrest 5 is not only prevented from being displaced forward by the fitting of the fourth engaging portions 50 and 54, but is also retained so as not to be laterally movable by the regulating action of the auxiliary rib 62 and the middle rib 24. Yes.

  The third engaging portions 49 and 53 hold the backrest 5 so that the backrest 5 cannot move up and down. The third engaging portions 49 and 53 do not have a function of preventing the backrest 5 from moving away from the user. Since the three engaging portions 49 and 53 are positioned on the left and right outer sides, for example, vibrations in the front-rear direction act on the vicinity of the third engaging portions 49 and 53 by the body pressure of the user in the back inner shell 16. However, the third front engaging portion 49 will not be disengaged from the third rear engaging portion 53.

  A stopper piece 50b that comes into contact with the fourth rear engagement portion 53 from the front side is provided at the base portion of the fourth front engagement portion 50. For this reason, the vicinity part of the 4th front part engaging part 50 among back inner shells 16 does not bounce in the front-back direction. Thereby, it can prevent reliably that the 3rd front part engaging part 50 remove | deviates from the 3rd rear part engaging part 53. FIG.

  When the back inner shell 16 is set slightly higher than the predetermined height and overlapped with the back outer shell 12 and then shifted downward, the first front engagement portion 47 fits into the first rear engagement portion 51 and the fourth The front engagement portion 50 engages with the fourth rear engagement portion 54, and the third engagement portion 49 is invited by the fitting of the first and fourth engagement portions 47, 51, 49, 54. The engagement hole 59 is fitted into the fourth rear engagement portion 53 by elastically deforming and then returning. Thereby, the backrest 5 is held so that it cannot move back and forth and cannot move back and forth. By turning the backrest 5 forward (or by turning it back upward), the third front engagement portion 49 can be pulled away from the third rear engagement portion 53. Then, when the backrest 5 is shifted upward, the engagement between the fourth front engaging portion 50 and the fourth rear engaging portion 54 can be released.

  For example, as shown in FIG. 7, square upper protrusions 63 are provided at the upper part of the back inner shell 16 and at the left and right intermediate parts, and the upper protrusions 63 fit tightly between the left and right inner ribs 28 of the back outer shell 12. It is like that. Further, on both the left and right sides of the upper protrusion 63, stepped portions 64 that are in contact with the middle protrusion 28 are formed. The front and rear positions and the left and right positions of the upper portion of the backrest 5 are also defined by the upper protrusion 63 and the stepped portion 64.

  For example, as shown in FIG. 7, a large number of tape catches 66 are formed along the circumferential direction on the back surface of the back inner shell 16 to fit and lock the tape attached to the periphery of the skin material 18. This group of tape catches 66 is located inside the side ribs 23 of the back outer shell 12. For this reason, the back inner shell 16 is not exposed to the outside of the side rib 23, and therefore, the aesthetic appearance is not impaired.

  In the present embodiment, since the rear engaging portions 51 to 54 are formed in two sets apart from each other in the vertical direction, the front engaging portions 47 to 50 are selected as either the upper or lower rear engaging portions 51 to 54. Thus, the height of the backrest 5 can be changed (adjusted) by the height dimension H (see FIG. 6) of the upper and lower rear engaging portions 51 to 54. That is, the low back type can be changed to the middle back type, or the middle pack type can be changed to the high back type.

  Providing the second rear engaging portion 52 on the back strut 13 as in the present embodiment has an advantage that an excessive load is prevented from acting on the back outer shell 12 and high body pressure support strength can be secured. Needless to say, the present invention can be applied to a chair of a type in which the height of the backrest cannot be changed. Further, the structure and position of the engaging portion for attaching the back outer shell to the back frame can be arbitrarily changed as necessary.

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

DESCRIPTION OF SYMBOLS 5 Backrest 8 Back frame 10 Rear part of back frame 11 Back support part of back frame 12 Back outer shell 13 Back support | pillar which is a part of back support part 16 Back inner shell 23 Side rib 24 Middle rib 25 Pocket part 29 Back part engagement part Lower stopper 30 as a part 30 Stopper hole as a part of the front engaging part 32 Corner engaging claw as a part of the rear engaging part 33 Corner engaging hole as a part of the front engaging part

Claims (3)

A back outer shell is attached to a back strut arranged on the back side of the seat, and the backrest is attached to only the back outer shell or the back outer shell and the back strut,
A group of ribs projecting forward is projected on the front surface of the back outer shell, and the back strut is disposed so as to fit in a space surrounded by the ribs, and on the front surface of the back outer shell. Is forming a pocket portion of a downward opening in which the upper portion of the back column fits from below,
Chair. A base on which the upper end of the leg support is fitted is arranged below the seat, and a substantially plate-like back support portion extending in the left-right direction is provided at the rear end of the back frame that is connected to the base so as to be tiltable backward. The back strut is standing up from both the left and right sides of the back support,
Further, a rear engagement that is hooked from behind and engaged with a front engagement portion formed on the back support portion and the left and right rear end portions of the back frame at the left and right intermediate portions and the left and right end portions of the lower portion of the back outer shell. The back engagement portion of the backrest is elastically deformed by pushing the lower portion of the backrest toward the front with the upper end portion of the back strut being fitted in the pocket portion, and then the front of the back outer shell. It is designed to engage with the engaging part,
The chair described in the backrest 1. Formed in the front surface of the back support portion is a vertically long longitudinal groove that opens forward,
The chair according to claim 1 or 2.

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