JP2016135411A - Chair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable adjusting an initial posture (initial angle) of a backrest while appropriately securing a lumbar support function.SOLUTION: A backrest 4 has a back inner shell 18, and the back inner shell 18 is connected to a back support 14 so as to rotate around both right and left ends of a lumbar support part 22. The lower end of the back inner shell 18 is connected to a back frame 13 through an initial angle adjusting device 15. A pin-like lock pin of an operation tool 40 is penetrated into the lower end of the back inner shell 18, and the initial posture of the backrest 4 is gradually changed by changing the support position of the lock pin. Since the longitudinal position of the lumbar support part 22 is not changed by changing the initial posture of the backrest 4, a sense of pressure and support deficiency with the change of the initial posture are not generated.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a chair that can change the initial posture (reference posture, initial angle) of the backrest in a side view.

  In a chair, it has been proposed to be able to change the initial posture of the backrest when the chair is not tilted backward. As an example of the posture change method, Patent Document 1 discloses that in a rocking chair in which the seat and the backrest are tilted integrally, the initial posture of the seat and the initial posture of the backrest are changed by changing the initial posture of the seat by lever operation. Are described to change together.

  In Patent Documents 2 and 3, in a rocking chair in which a backrest is attached to a back frame that is connected to a base so as to be able to tilt backward, the initial posture of the backrest is changed by adjusting the posture of the back frame in a non-locking state. Is described. Further, in Patent Document 4, when the backrest is attached to the left and right brackets fixed to the seat, the backrest is connected to the bracket so as to rotate about the middle part of the top and bottom, and the rotation posture is changed by operating the pin. It is described to change.

  Further, in Patent Documents 5 and 6, in a chair in which a backrest having a lumbar support portion is attached to the back frame, the backrest is connected to the back frame so as to rotate around its upper end, and the lumbar support portion It is described that the side view posture of the backrest is changed by changing the protruding amount.

Japanese Examined Patent Publication No. 47-49543 JP 2002-142897 A Special table 2010-516433 Japanese Patent Publication No.46-8447 Japanese Patent No. 4185754 Japanese Patent No. 4220191

  Now, it has been pointed out that it is important to support the lumbar part (especially around the third lumbar vertebrae) of a seated person in a chair, and therefore, it is widely used to provide a lumbar support part that protrudes forward in a side sectional view. . In other words, when a person sits on a chair and works, the lumbar support part supports the person's waist, so that the person can take a proper posture with his back straightened, thereby reducing the burden on the body. Can be reduced.

  On the other hand, the initial posture of the backrest is changed to suit the user's preference, but it is not preferable that the contact with the body changes by changing the initial posture. In other words, it is not preferable that the body support position shifts back and forth or the body contact position shifts up and down by changing the initial posture of the backrest.In a chair having a lumbar support part, the lumbar support function is accurately set. It is preferable that the initial posture can be changed while being held.

However, since Patent Documents 1 to 3 change the initial posture by tilting the backrest around the rotation fulcrum of the back frame, the backrest moves back and forth as a whole as the initial posture is adjusted. For this reason, there is a possibility that the body may have a feeling of being pushed up, or the support function of the body may be reduced.

  Since Patent Documents 5 and 6 move the lumbar support part back and forth, it is difficult to respond to a request to change the initial posture of the backrest without changing the lumbar support function.

  Since the backrest of Patent Document 4 rotates around its upper and lower middle parts, it can be said that the fit to the body is high, but since the backrest does not have a lumbar support part, There is a risk that the lower end protrudes forward and gives a feeling of being pushed up. Further, since the posture is changed by operating a pin provided on the upper end portion of the bracket, it is difficult to change the posture while sitting, and there is a problem that the operability is poor.

  The present invention has been made in view of such a situation, and it is possible to change the initial posture of the backrest while appropriately maintaining the support function of the body, and a chair that takes into consideration the operability of the posture change and the like. It is to be provided.

  The present invention has the structure of each claim. The invention of claim 1 has a seat and a backrest arranged behind the seat, and the backrest is attached to a back frame extending rearward from below the seat, and the backrest is a seated person. The lumbar support part has a lumbar support part that protrudes from the rear in a side sectional view and supports the lumbar part from behind, and the back frame is configured so that the backrest rotates around a position at a height position of the lumbar support part in a side view. On the other hand, an initial angle adjustment device that changes the side view posture of the backrest is provided on the back frame or the backrest so that it can be operated while a person is seated. The “back frame or backrest” includes a case where it is provided on either one and a case where it is provided on both.

  According to a second aspect of the present invention, in the first aspect, the back frame is connected to a base provided at an upper end of a leg so as to tilt backward against the spring means, and the back frame is more than the base of the back frame. The initial angle adjusting device is provided at a position lower than the seat surface behind.

  The invention of claim 3 is the invention according to claim 1 or 2, wherein the back frame has bifurcated back struts whose upper end portions are located in the vicinity of both left and right side portions of the lumbar support in the backrest, The backrest is rotatably connected to the upper end portion, and the lower end portion of the backrest is supported by a substantially intermediate portion between the left and right back posts of the back frame.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the front surface of the lumbar support portion is formed in a concave shape facing forward in a plan sectional view. It is located on the nearer side than the intermediate portion, and both left and right end portions of the lumbar support are rotatably connected to the back frame.

  A fifth aspect of the present invention relates to an operation means. In any one of the first to fourth aspects, the initial angle adjusting device moves forward and backward based on a left / right slide type operation tool and a slide operation of the operation tool. And a locking portion provided at the lower end of the backrest, the stopper and the locking portion can be fitted in each posture with the initial angle of the backrest changed, and the operation tool is operated by sliding. When the stopper is retracted, the engagement between the stopper and the lock portion is released.

A fifth aspect of the present invention relates to an operating means. In any one of the first to fourth aspects of the present invention, the initial angle adjusting device includes an operation tool that rotates about a horizontally long axis, and a horizontally long axis. A circumferential cam that rotates around, and the circumferential cam has a plurality of cam surfaces with different distances from the rotation axis, and the lower end of the backrest is connected to the plurality of cam surfaces. By selectively supporting the backrest, the initial posture of the backrest can be changed in a plurality of stages.

  The invention according to claim 7 is a preferred embodiment of the invention according to claim 6. In this invention, the circumferential cam has a pair of left and right cylindrical portions projecting in the direction of the rotation axis. While a part of the operation tool penetrates through the tube portion so as not to be relatively rotatable, the back frame includes a pair of left and right bearing ribs that rotatably hold the operation tool between the left and right bearing ribs. A circumferential cam is provided, and on the inner surface of the left and right bearing ribs, there are formed long and narrow long grooves into which the cylindrical portion of the circumferential cam fits so as to face each other, The face cam can be fitted into the long groove by an operation of inserting the face cam between the left and right bearing ribs in an inclined state and then returning the posture.

  In the present invention, since the backrest changes its initial posture (initial angle) by rotating around the lumbar support portion, the front-rear position of the lumbar support portion does not change greatly by changing the initial posture. Therefore, there is no problem that a feeling of pushing up to the body or a support function is lowered by changing the initial posture. That is, the initial posture of the backrest can be adjusted according to the user's preference while appropriately securing the lumbar support function. In addition, since the initial angle adjustment device can be operated while a person is seated, the person can adjust the posture while trying to feel the body and is user-friendly.

  Claim 2 is applied to a rocking chair, and since the initial angle adjusting device is located behind the base and lower than the seating surface, a person can easily operate by stretching his hand back while sitting. It does not get in the way or deteriorate the appearance.

  Although various shapes can be adopted for the back frame, if a bifurcated back support is provided as in claim 3 and the backrest is connected to the upper end portion, it is possible to eliminate waste and make the appearance clean. In addition, since the lower end of the backrest is supported by the left and right middle part of the back frame, the backrest is attached to the back frame in a three-point support state, which makes the backrest stable while having a simple structure Can hold.

  In general, the backrest is curved in a forward concave shape in a plan view so as to fit the body, and the lumbar support portion is preferably curved in a forward concave shape in a plan sectional view. Then, in such a form in which the lumbar support part is curved in a forward concave shape in a plan view, as shown in claim 4, when the left and right ends of the lumbar support part are connected to the back frame, the left and right spans of the connecting part of the backrest are obtained. The support stability of the backrest can be improved by making it as large as possible, and the lumbar support portion is allowed to be deformed in the front-rear direction by body pressure, so that the cushioning and fitting properties can be further improved.

  The configuration of the initial angle adjusting device can be embodied in various ways. However, if the operation tool is configured to slide left and right as in claim 5, there is an advantage that the operation tool can be arranged as close to the back frame as possible. Using the peripheral cam with the operating tool as a rotary type as in 6 has an advantage that the initial posture of the backrest can be easily changed with one touch.

According to the seventh aspect of the present invention, since the cylindrical portion of the circumferential cam is fitted in the long groove of the bearing rib, even if a load due to tilting of the backrest acts on the circumferential cam, the load is passed through the cylindrical portion. It can be supported by the inner surface of the long groove. Therefore, the operation tool is not burdened and is excellent in strength. In addition, the peripheral cam can be set by inserting it into the left and right bearing ribs by inserting it between the left and right bearing ribs in a tilted state, and is easy to assemble. Since a hole for fitting the circumferential cam from below is not required in the bearing rib, it is excellent in strength and aesthetics.

The chair which concerns on embodiment is shown, (A) is the perspective view seen from the front, (B) is the perspective view seen from back, (C) is the isolation | separation side view which shifted the back frame back. FIG. It is the perspective view which abbreviate | omitted the support mechanism part and the seat part. (A) is the perspective view which looked at the back frame from the bottom, (B) is the isolation | separation perspective view in the state which turned over the 2nd back frame. (A) (B) is the isolation | separation perspective view of a backrest and a 2nd back frame. (A) and (B) are separation perspective views for explaining an initial angle adjusting device. (A) is a separated perspective view of an operating tool and a backrest, (B) is a perspective view of an initial angle adjusting device, and (C) is a perspective view of a lower end portion of a back inner shell. It is VIII-VIII sectional view taken on the line of FIG. (A) is a longitudinal side view of the main part, (B) is a cross-sectional view taken along the line BB of (A). (A) is a cross-sectional perspective view showing the initial angle adjusting device, and (B) is a cross-sectional view taken along the line XB-XB in FIG. It is a vertical side surface of the position fixing means. It is a figure which shows 2nd Embodiment, (A) is a whole perspective view, (B) is the isolation | separation perspective view of the principal part. It is a figure which shows 2nd Embodiment, (A) is a cross-sectional perspective view, (B) is sectional drawing in the state which changed the cutting position, (C) is the schematic diagram which took out a part of (B). It is a fragmentary perspective view of 3rd Embodiment. It is a separate perspective view of a 3rd embodiment. It is a figure which shows 3rd Embodiment, (A) is a cutting | disconnection perspective view, (B) is the perspective view which looked at the initial angle adjustment apparatus from the downward direction. It is a whole perspective view of 4th Embodiment. It is a fragmentary perspective view of 4th Embodiment. It is a separation perspective view of a 4th embodiment. (A) (B) is the isolation | separation perspective view of 4th Embodiment. (A) is a perspective view which shows the fitting state of a surrounding surface cam, (B) is a separate perspective view of an operation tool and a surrounding surface cam. (A) is a longitudinal front view of the main part, (B) is a cross-sectional view taken along the line BB of (A).

  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 According to First Embodiment First, an outline of a chair according to the first embodiment will be described mainly based on FIGS. 1 to 3 (the basic configuration of the chair is common to each embodiment). .) This embodiment is applied to a swivel chair that is frequently used for office work and the like, and the chair is provided with a leg device displaying only the leg support 1 (see FIG. 1C) and the upper end of the leg support 1. It has a fixed base 2, a seat 3 disposed on the base 2, and a backrest 4 on which a seated person can lean. The base 2 is formed in a box shape opened upward.

For example, as shown in FIG. 2, an intermediate metal fitting (seat receiving metal fitting) 5 made of a metal plate is arranged on the base 2, and a resin seat outer shell 6 is attached to the intermediate metal fitting 5. Seat 3
Has 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, description thereof will be omitted.

  For example, as shown in FIG. 2, the first back frame 7 is connected to the base 2 so as to be able to tilt backward, and the second back frame 8 located behind the first back frame 7 is fixed to the first back frame 7. A backrest 4 is attached to the second back frame 8. The first back frame 7 has an arm portion 7 a that extends forward at an outer position of the base 2, and the front end portions of the left and right arm portions 7 a are connected to the base 2 by a horizontally elongated first shaft 9. Accordingly, the backrest 4 tilts back and forth around the axis of the first shaft 9. The first back frame 7 is an aluminum die-cast product, and the second back frame 8 is a resin-molded product, but either a metal die-cast product such as aluminum or a resin-molded product can be employed. is there.

  The chair according to the present embodiment is a synchro-type chair in which the seat 3 is retracted in conjunction with the backward tilt of the backrest 4 and, as can be understood from FIG. The rear part of the intermediate metal fitting 5 is connected to a bracket part 11 projecting upward from the first back frame 7 by a horizontally long second shaft 12. Yes. Inside the base 2, a reaction force unit that elastically supports the back tilt of the backrest 4 and the seat 3, a locking gas cylinder that controls the tilting of the backrest 4, and the like are arranged directly with the present invention. Since there is no relationship, the description is omitted.

  The second back frame 8 has a base portion 13 fixed to the first back frame 7 and a square back strut 14 projecting upward from both left and right end portions thereof, and a backrest on the upper end portion of the back strut 14. 4 is connected to be tiltable back and forth, and the base 13 is provided with a part of the initial angle adjusting device 15. By changing the support position of the backrest 4 in the front-rear direction by the initial angle adjusting device 15, the initial posture (initial angle) of the backrest 4 in the non-locking state is adjusted.

(2). Backrest and its mounting structure Next, details of each part will be described with reference to FIG. First, details of the backrest 4 and its mounting structure will be described. As shown in FIG. 1A, the backrest 4 has a back inner shell 18 that is a molded product of resin such as polypropylene, a cushion 19 stretched on the front surface, and a skin material 20 such as a cloth. doing. Therefore, the outer shape of the backrest 4 is the same as the outer shape of the back inner shell 18.

  The skin material 20 is configured in a bag shape and covers the entire back inner shell 18 from above. When the skin material 20 is configured in a bag shape as in the present embodiment, a thin cushion sheet can be disposed on the back surface of the back inner shell 18 to give tension to the skin material 20. As shown in FIG. 5A, a large number of grid-like reinforcing ribs 21 extending in the vertical and horizontal directions are formed on the back surface of the back inner shell 18.

  For example, as shown in FIG. 3 and FIG. 9 (A), the backrest 4 has a lumbar support portion 22 against which the waist of a seated person hits. Therefore, the backrest 4 has a forward projecting shape in a side view and a longitudinal side view. It has become. Strictly speaking, the back inner shell 18 is curved so that the lumbar support portion 22 is located in the foremost position in a longitudinal side view. Further, the back inner shell 18 is gently curved in a concave shape in a plan view, but the degree of curvature is greatest at the lumbar support portion 22, and the degree of curvature decreases as it goes upward, and is flat at the upper end. It is a close form.

For example, as shown in FIG. 3, the backrest 4 is set such that the left and right lateral width is the largest at the lumbar support portion 22 and the lateral width decreases as the distance from the lumbar support portion 22 increases. Therefore, the backrest 4 (back inner shell 18) has a shape close to a substantially hexagonal shape when viewed from the front. Since the lumbar support portion 22 is close to the lower portion of the back inner shell 18, the backrest 4 is precisely in the form of a downwardly swelled hexagonal shape, and the left and right end portions of the lumbar support portion 22 are laterally oriented in the front view. It has the shape of a protruding mountain.

  And the side connection part 23 for connecting with the back support | pillar 14 is provided in the right-and-left end part of the lumbar support part 22 in the back inner shell 18. The side connection part 23 protrudes forward from the periphery. A longitudinal rib 24 extending upward from the side connecting portion 23 is provided on the front side portion of the back inner shell 18.

  As shown in FIG. 4, the base portion excluding the arm portion 7a of the first back frame 7 basically has a plate shape or a block shape, while the base portion 13 of the second back frame 8 also has a plate shape. Or it is a form close | similar to block shape, the front part of the base 13 in the 2nd back frame 8 is piled up on the rear part of the 1st back frame 7, and both are fastened with the bis | screw 25. In this case, a protrusion 13 a provided at the front end of the base 13 in the second back frame 8 is fitted into a space 26 in the rearward opening formed in the first back frame 7, and a horizontally long shape provided in the first back frame 7. The fitting protrusion 27 and a horizontally long fitting groove 28 provided on the lower surface of the base portion 13 of the second back frame 8 are fitted. For this reason, both the back frames 7 and 8 are firmly fastened by the single screw 25.

  For example, as shown in FIG. 5, a fist-like head portion 14a that opens forward is formed at the upper end of the back column 14 in the second back frame 8, and a bearing portion that opens forward is formed on the head portion 14a. 29 is formed integrally. On the other hand, a boss portion 30 that fits into the bearing portion 29 is formed integrally with the side connecting portion 23 of the back inner shell 18, and the side connecting portion 23 of the back inner shell 18 is connected to the back strut by the fitting of both. It is connected to the 14 heads 14a so that it cannot be removed forward. The boss part 30 is integrally connected to a rib 31a provided on the outer side and a regulation plate 31b provided on the inner side.

  As clearly shown in FIG. 10B, the bearing portion 29 has a constricted portion, while the boss portion 30 has an oval cross section. However, when the backrest 4 is set in a predetermined posture, the boss portion 30 is substantially omitted. While the horizontal posture is set, the opening direction of the bearing portion 29 is set to open obliquely upward with respect to the horizontal. For this reason, the boss part 30 can be fitted into the bearing part 29 by making the backrest 4 tilted backward with respect to a predetermined attitude, and when the lower end of the back inner shell 18 is connected to the second back frame 8, the backrest Even if a forward external force acts on the boss 4, the boss 30 is held so as not to be detached from the bearing 29. Therefore, the backrest 4 can be easily attached.

  As shown in FIGS. 5 and 8, a load receiving portion 32 having an arc surface having a curvature much larger than the radius of the boss portion 30 is formed in a portion of the head portion 14 a of the back column 14 inside the bearing portion 29. On the other hand, the side connecting portion 23 of the back inner shell 18 is integrally provided with an arc-shaped load application portion 33 that fits into the load receiving portion 32. Since the load bearing portion 33 is in contact with the load receiving portion 32 in a wide area (surface contact), the back inner shell 18 is stably supported by the left and right back struts 14 without being hindered from rotating back and forth. It is supported by.

  In addition, a groove 32a is formed between the bearing portion 29 and the load receiving portion 32 in the head portion 14a of the back column 14, and the regulation plate 31b of the back inner shell 18 is fitted into the groove 32a so that it cannot be displaced from side to side. waiting. As described above, the back inner shell 18 is held so as not to be laterally displaced by the fitting of the groove 32a and the regulating plate 31b. Therefore, a backward load acts on the lumbar support portion 22 so that the side connecting portion 23 faces inward. Even if pulled, the side connecting portion 23 does not move inward. For this reason, the mounting strength is high. The bottom surface of the groove 32a and the outer periphery of the regulating plate 31b are formed in an arc shape having a curvature around the axis of the boss portion 30 in a side view, and thus the back inner shell 18 rotates around the axis of the boss portion 30. Is allowed.

  As described above, in the assembly structure of the upper end of the back column 14 and the back inner shell 18, the back-and-forth direction is prevented, the load applied to the back is supported, and the right and left displacement is prevented at different specific parts. Specifically, the boss portion 30 and the bearing portion 29 prevent the detachment in the front-rear direction, so that the boss portion 30 does not have other functions (support of load on the back, prevention of left-right displacement). Is loosely fitted to the bearing portion 29 with a slight clearance between its outer peripheral surface and the inner peripheral surface of the bearing portion 29, and the boss portion 30 is larger than the left and right width dimensions of the bearing portion 29. By setting the left and right width dimensions to be slightly wider, the rib plate 31 a is prevented from hitting the side surface of the bearing portion 29. Further, the rear end surface of the restriction plate 31 is set so as not to hit the bottom surface of the groove 32a in the back column 14.

(3) Initial angle adjusting device The lower left end portion of the back inner shell 18 is connected to the second back frame 8 via the initial angle adjusting device 15 at the left and right intermediate portions. This point will be described next.

  For example, as shown in FIGS. 7A and 7C, a lower connecting portion 35 protruding forward is provided at the left and right intermediate portion of the lower end portion of the back inner shell 18, and the lower connecting portion 35 opens downward. A center groove 36 is formed, and a pin hole 37 is opened across the center groove 36. Furthermore, upper and lower ribs 38 and 39 connected to the lower connecting portion 35 are provided on the right portion of the lower connecting portion 35 at the lower end portion of the back inner shell 18, and an operation tool (slide) is provided between the upper and lower ribs 38 and 39. Type lever) 40 is slidably mounted to the left and right. The lower connecting portion 35 and the operation tool 40 are components of the initial angle adjusting device 15. The operation tool 40 is provided with a finger hook 40a that can be grasped by a person.

  The operation tool 40 is integrally formed with a pin-like lock pin 41 that fits into the pin hole 37 of the lower connecting portion 35. Therefore, when the operating tool 40 is slid left and right, the lock pin 41 can be projected and retracted in the center groove 36 of the lower connecting portion 35. The lock pin 41 is an example of a stopper described in the claims. The upper rib 38 is provided with a claw 42 that holds the operation tool 40 so as not to be detached from the back inner shell 18.

  Further, the operating tool 40 is provided with a spring disposing space 43a that opens toward the back inner shell 18 and a stroke restricting space 43b. The spring disposing space 43a is located on the lock pin 41 side, and the stroke restricting space 43b is located on the finger hooking portion 40a side. On the other hand, the back inner shell 18 is provided with a spring receiving protrusion 44a that enters the spring placement space 43a and a stroke restriction projection 44b that enters the stroke restriction space 43b, and the spring receiving protrusion 44a and the spring placement space 44b. A compression coil spring 43c is disposed between the inner surface 43e of the place 43a. For this reason, the operating tool 40 is urged so that the lock pin 41 fits into the lower connecting portion 35 and becomes free (so that the lock position is maintained). The spring 43c is disposed in the spring placement space 43a by being pushed in from a window hole 43e provided in the front surface of the operation tool 40.

  The retraction position when the operation tool 40 is pulled outward by hand is controlled by applying the inner surface of the stroke restricting space 43b to the stroke restricting protrusion 44b. The forward position when the operating tool 40 is pushed by a spring may be regulated by applying the inner surface of the spring placement space 43a to the stroke regulating projection 44b, or the end of the operating tool 50 may be You may carry out by contacting to the side surface of the lower connection part 35. FIG.

As shown in FIG. 7B, a block-like lock body 45 is provided at the rear end of the base portion 13 of the second back frame 8 so as to be fitted into the center groove 36 of the lower connecting portion 35 of the seat inner shell 18 from below. The lock body 45 has three lock holes 46 into which the lock pins of the operation tool 40 are fitted. Therefore, the lock body 45 is also a component of the initial angle adjusting device 15. The three lock holes 46 are present on an arc centered on the rotation fulcrum of the back inner shell 18, and the initial posture of the backrest 4 is obtained by selectively fitting the lock pins into any of the lock holes 46. Can be changed in three stages. Needless to say, the number of the lock holes 46 is not limited to three, but may be two or four or more. The lock hole 46 is an example of a lock portion described in the claims.

  The lock body 45 is made of resin and is formed separately from the second back frame 8, and is fitted into the base 13 of the second back frame 8 from below. For this reason, for example, as shown in FIG. 6, the base 13 of the second back frame 8 has a hole 47 into which the lock body 45 fits from below, and a center guard portion 48 that supports the lock body 45 from behind. The center guard portion 48 is provided with a forward opening groove 49 into which the lock body 45 is fitted. The lock body 45 is provided with a front wall 45a that restricts the lower end of the back inner shell 18 from moving forward greatly.

  As shown in FIG. 9, a recess 50 into which the lock body 45 enters is formed on the lower surface of the second back frame 8, and a lower flange 45 b provided on the lock body 45 is overlapped on the bottom surface of the recess 50. And the support claw 51 is provided in the inner surface of the recessed part 50, and the lock body 45 is hold | maintained so that it cannot fall by the lower flange 45b getting over the support claw 51 from the downward direction. The lower flange 45b and the support claw 51 are formed with inclined surfaces for guiding. The lower flange 45b is provided with a hole 45c for facilitating deformation. The lock body 45 can be provided integrally with the second back frame 8, but if it is configured separately from the second back frame 8 as in the present embodiment, there is an advantage that the processing becomes easy.

(4). Posture Fixing Means Depending on the user, the initial posture adjustment function of the backrest 4 may not be required. Therefore, in the present embodiment, the posture of the backrest 4 can be kept constant without using the initial angle adjusting device 15. That is, in this embodiment, the initial posture of the backrest 4 can be kept constant by using the posture fixing means without using the initial angle adjusting device 15. This point will be described next.

  For example, as shown in FIG. 6A, side guard parts 53 having upper and lower openings having a pair of right and left restricting ribs are formed on the left and right sides of the center guard part 48 in the base part 13 of the second back frame 8, A block-shaped side regulating body 54 is fitted into the side guard portion 53 from below. The side restricting body 54 is held by the side guard portion 53 so as not to move left and right, and is supported by a support rib 55 from the rear. As shown in FIG. 11, a flange 54 a is provided at the lower end of the side regulating body 54, and the flange 54 a overlaps the bottom surface of the recess 13 c provided in the base portion 13 of the second back frame 8. Similarly to the lock body 45, the side restricting body 54 is held by the engaging claw 13d so as not to drop.

  The side restricting body 54 is formed with an engaging groove 56 that opens upward in a side view, and a restricting shaft 57 provided at the lower end of the back inner shell 18 is formed in the engaging groove 56 as shown in FIG. By fitting, the backrest 4 is held so that the initial posture cannot be changed. The restriction shaft 57 is formed integrally with the back inner shell 18 via a pair of left and right rearward facing ribs 48. In FIG. 6 and FIG. 7, the operating tool 40 and the side restricting body 54 are displayed together for convenience. However, when the initial posture of the backrest 4 is changed by the initial angle adjusting device 15, the restricting body 54 is the second one. When it is not attached to the back frame 8 and the initial posture adjustment function 15 is not required, the operation tool 40 and the lock body 45 are not attached.

(5) Summary In the above configuration, the operation tool 40 is pulled outward (retracted), and the lock pin 41 is removed from the lock hole 46 of the lock body 45 and re-inserted into the other lock hole 46, so that the backrest 4 Can be adjusted in three stages.

  In this case, since it rotates around the height position of the lumbar support portion 22 of the backrest 4, even if the initial posture of the backrest 4 is changed, the front and rear positions of the lumbar support portion 22 do not change, and therefore the backrest. The change of the initial posture 4 does not change the contact state of the lumbar support portion 22 with the body. Moreover, even if the initial posture of the backrest 4 is changed, the lumbar support function is always exhibited.

  For example, as apparent from FIG. 1C, the lower end of the backrest 4 is located below the seating surface, and therefore the initial angle adjusting device 15 is also disposed below the seating surface. For this reason, the initial angle adjusting device 15 does not touch the body. Also, since the seated person can reach the back and operate the operation tool 40, the initial angle can be adjusted very easily. In order to adjust the initial angle of the backrest 4, the posture of the backrest 4 is changed after the operation tool 40 is pulled to release the lock. As a method of changing the posture of the backrest 4, the lower part of the backrest 4 is moved with the left hand. The backrest 4 may be moved back and forth, or the backrest 4 may be rotated by pushing the upper or lower end of the backrest 4 with the body.

  For example, as shown in FIG. 7B, a rear wall 13b protruding upward is integrally formed at the rear end of the base portion 13 of the second back frame 8, and the center guard 48 and the side guard 53 are formed on the rear wall 13b. It is connected to. Further, the base of the back column 14 is connected to the rear wall 13b. Since the rear wall 13b exhibits a rib effect, the second back frame 8 has high strength. In the initial posture in which the backrest 4 is most raised, there is a gap between the lower end of the backrest 4 (back seat inner shell 18) and the rear wall 13b of the second back frame 8 with enough margin for human fingers to enter. Is vacant. Therefore, a person does not pinch a finger.

(6). Second Embodiment Next, a second embodiment shown in FIGS. In this embodiment, the back frame 60 has a single structure, and the back column 14 is integrally provided at the rear end of the back frame 60. The point that the lumbar support portion 22 of the back inner shell 18 is connected to the upper end of the back column 14 is the same as in the first embodiment.

  In the second embodiment, the operation tool 40 is a rotary handle, and is rotatably held by a pair of left and right bearing ribs 61 provided at the left and right intermediate portions of the back frame 60. The tip of the operating tool 40 positioned between the left and right bearing ribs 61 is a prismatic part 40b, and the peripheral cam 62 is relatively unrotatable (that is, rotates together with the operating tool 40). Like). The circumferential cam 62 has one center cam portion 63 and a pair of left and right side cam portions 64 located on the left and right sides thereof. On the other hand, the lower inner shell 18 is integrally provided with a lower connecting portion 65 that opens downward so that the circumferential cam 62 can be fitted from below (the lower connecting portion 65 is manufactured separately, It may be fixed to the shell 18).

  The center cam part 63 and the side cam part 64 have their outer peripheral surfaces as cam surfaces, and the front inner surface of the lower connecting part 65 forms a front regulating surface 65a with which the center cam part 63 abuts, and the rear inner surface of the lower connecting part 65 is It forms a rear regulating surface 65b with which the side cam portion 64 abuts. First to third cam surfaces 63a to 63c having different heights from the shaft center are formed on the outer periphery of the center cam portion 63, and first to first cam surfaces 63a to 63c having different heights from the shaft center are also formed on the outer periphery of the side cam portion 64. Third cam surfaces 64a to 64c are formed. The lower connecting portion 65 opens downward as described above, but the front-rear distance L0 between the front restricting surface 65a and the rear restricting surface 65b is set to increase as it goes downward.

  Now, as the person leans against the backrest 4, as shown by the white arrow X in FIG. 13C, an external force that tries to rotate around the axial center of the boss portion 30 acts on the back inner shell 18. The external force is transmitted from the rear restricting surface 65b of the lower connecting part 65 to the prism 40b of the operating tool 40 via the side cam 63. That is, the backrest load generated by the locking of the backrest 4 is supported by the operation tool 40 via the side cam portion 64.

  And the back control surface 65b of the lower connection part 65 is orthogonally crossed with the tangent of the rotation locus | trajectory O at the time of the initial angle adjustment of the backrest 4 which passes along the axial center of the operation tool 40 by side view. For this reason, the side cam part 64 does not try to rotate by the back load accompanying rocking, and the back load is stably supported. That is, there is no problem that the side cam portion 64 rotates unintentionally due to the back load. Although the front restricting surface 65a of the lower connecting portion 65 is inclined with respect to the rear restricting surface 65b, the inside of the lower connecting portion 65 has a tapered shape in which the front and rear width expands downward. When assembling the backrest 4 to 60, the lower connecting portion 65 can be easily fitted into both the cam portions 63 and 64, and the die can be easily removed when molding using a mold.

  When the first cam surface 63a of the center cam portion 63 is in contact with the front restricting surface 65a, the first cam surface 64a of the side cam portion 64 is in contact with the rear restricting surface 65b. When the second cam surface 63b of the cam portion 63 is in contact with the front restriction surface 65a, the second cam surface 64b of the side cam portion 64 is in contact with the rear restriction surface 65b and the third cam surface 63c of the center cam portion 63 is contacted. Is in contact with the front regulating surface 65a, the third cam surface 64c of the side cam portion 64 is in contact with the rear regulating surface 65b. A rear wall 60 a is provided at the rear end of the back frame 60.

  In the present embodiment, the initial angle of the backrest 3 can be adjusted in three stages by rotating the operation tool 40, and the backrest 4 is held so as not to be rattled back and forth. In addition, although resistance arises with respect to rotation of the circumferential cam 62, the circumferential cam 62 can be rotated by elastically deforming the lower connecting portion 65. The left and right side plates of the lower connecting portion 65 are provided with long holes 71 into which the operating tool 40 is loosely fitted in order to allow the lower connecting portion 65 to rotate.

  In this embodiment, the side connecting portion 23 is first connected to the leg support 14, and then the circumferential cam 62 is fitted into the lower connecting portion 64 from below. Therefore, as shown in FIG. 13A, the back frame 60 has a relief hole 60b through which the circumferential cam 62 is inserted.

  Now, since the front-rear distance between the front and rear regulating surfaces 65a, 65b increases as it goes downward, the height position where the first cam surfaces 63a, 64a hit, the height position where the second cam surfaces 63b, 64b hit, The height positions where the third cam surfaces 63c and 64c hit differ.

  Therefore, the distance between the front and rear restricting surfaces 65a and 66b at the height position where the first cam surfaces 63a and 64a abut is L1, and the front and rear restricting surface 65a at the height position where the second cam surfaces 63b and 64b abut. , 65b is L2, and the distance between the front and rear restricting surfaces 65a, 65b at the height position where the third cam surfaces 63c, 64c hit is L3, the sum of the heights of the first cam surfaces 63a, 64a. (69a + 70a) is set to approximately the same dimension as L1, the sum of the heights of the second cam surfaces 62b and 63b (69b + 70b) is set to approximately the same dimension as L2, and the sum of the heights of the third cam surfaces 63c and 64c. (69c + 70c) is set to approximately the same size as L3. As a result, the backrest 4 can be held in a stable state without rattling while the regulating surfaces 65a and 66b are inclined downward.

(7) Third Embodiment Next, a third embodiment shown in FIGS. 14 to 16 will be described. In this embodiment, a back column 72 that is tilted forward as viewed from the side is provided on the left and right middle portion of the back frame (not shown), and a pivot member 73 that is square in a side view is connected to the upper end of the back column 72 by a horizontally long pin 74. The back inner shell 18 is fixed to the upper half portion of the rotating member 73. The back column 72 is fixed to a back frame (not shown), but it is preferable that the back column 72 be integrated with the back frame.

  The rotation member 73 is connected by a pin 74 in the vicinity of the bent vertex portion, and the vertex of the lumbar support portion 22 of the back inner shell 18 and the vertex of the rotation member 73 substantially coincide with each other. For this reason, the back inner shell 18 rotates around the height position of the lumbar support portion 22. The back column 72 has left and right side plates 72a, and the rotating member 73 is disposed between the left and right side plates 72a. In this embodiment, the back column 72 and the rotation member 73 are manufactured by sheet metal processing, but a die-cast product or a resin molded product can also be adopted.

  By regulating the angle of the rotating member 73 with the initial angle adjusting device 15, the initial posture of the back inner shell 18 is adjusted. The initial angle adjusting device 15 is basically the same as in the second embodiment, and the circumferential cam 62 is rotated by the operation tool 40. The operation tool 40 is rotatably held by the back column 72, and although not shown, a grip (handle) is provided at the right end. In this embodiment, a resin lower connecting portion 65 is fixed to the lower portion of the rotating member 73 with a screw or the like.

(8) Fourth Embodiment Next, a fourth embodiment shown in FIGS. 17 to 22 will be described. The fourth embodiment is almost the same as the second embodiment. Therefore, the same reference numerals are given to the same parts as the second embodiment, and the description will be omitted as much as possible, and the differences will be mainly described. The back frame basically has the same structure as that of the first embodiment, and a bearing rib 61 is provided on the second back frame 8.

  For example, as shown in FIG. 19, in this embodiment, bearing cylindrical portions 75 are integrally formed on the left and right ends of the circumferential cam 62, while the cylindrical portion 75 is fitted on the inner side surface of the bearing rib 61. A longitudinal long groove 76 is formed. Although the square portion 40a of the operation tool 40 penetrates the cylindrical portion 75 of the circumferential cam 62, a pair of protrusions 77 are formed at the base of the square portion 40a of the operation tool 40 as clearly shown in FIG. On the other hand, a pair of notches 78 into which the projections 77 are fitted are formed in one cylindrical portion 75 of the circumferential cam 62. For this reason, the integrity of the circumferential cam 62 and the operation tool 40 is increased.

  A small-diameter portion 79 is formed at the tip of the operation tool 40, and the small-diameter portion 79 is rotatably fitted in a bearing hole 80 provided in the other bearing rib 61. A pair of stopper pieces 81 projecting in a direction orthogonal to the shaft center is provided at the tip of the small diameter portion 79 of the operation tool 40, while the stopper piece 81 cannot be removed from the outer surface of the other bearing rib 61. A stepped portion 81 is formed. The bearing hole 80 of the other bearing rib 61 is an elongated hole that is long in the front-rear direction. Therefore, the stopper piece 81 is fitted sideways into the bearing hole 80, and the stopper piece 81 is fitted into the bearing hole 80. When the operation tool 40 is rotated by 90 °, the operation tool 40 is held so as not to be detached.

  The operation tool 40 is inserted after the circumferential cam 62 is set between the left and right bearing ribs 61. As shown in FIG. 21B, the protruding direction 83 of the protrusion 77 and the protruding direction 84 of the stopper piece 81 are orthogonal to each other. As shown in FIG. 19, a rib 40 b for displaying the posture of the backrest 5 is provided at the proximal end of the grip in the operation tool 40.

As shown in FIGS. 21 and 22, the circumferential cam 62 is fitted in a procedure in which the rotational axis is fitted between the left and right bearing ribs 61 in a posture inclined with respect to the horizontal and then returned to the horizontal posture. . Since the long groove 76 is long in the vertical direction, the left and right cylindrical portions 75 can be fitted into the left and right long grooves 76 by tilting the circumferential cam 62 in a front view, and when the posture is returned so that the rotation axis is horizontal, The face cam 62 is held so as not to move back and forth.

  Then, after attaching the circumferential cam 62 and the operating tool 40 to the bearing rib 61, the lower connecting portion 65 of the backrest 4 is fitted into the cylindrical portion 75 of the circumferential cam 62. In this case, as shown in FIG. 19, the long hole 71 of the lower connecting portion 65 is inclined in a side view so that the upper part is located at the rear and the lower end is located at the front, and is opened downward. Therefore, it can be fitted into the cylindrical portion 75 of the circumferential cam 62 that is set in advance. As clearly shown in FIG. 20B, an elastic piece 65a that narrows the groove width of the opening is provided inwardly (upward) at the opening of the elongated hole 71 in the lower connecting portion 65. Therefore, the lower connecting portion 65 is fitted into the cylindrical portion 75 of the circumferential cam 62 and the elastic piece 65a is elastically deformed. When the lower connecting portion 65 is fitted into the cylindrical portion 75 of the circumferential cam 62, The connecting portion 65 is held in a state where it does not come off from the cylindrical portion 75 of the circumferential cam 62. For this reason, the posture of the backrest 4 can be maintained during assembly.

  In addition, as described in the first embodiment, when the boss portion 30 of the side connecting portion 23 is fitted into the bearing portion 29 of the back column 18, the backrest 4 is inclined backward. Since the hole into which the tool 40 is fitted is a long hole 71, the boss part 30 can be fitted into the bearing part 29 and the lower connecting part 65 can be fitted into the operation tool 40 at the same time. When the backrest 4 is tilted backward after the both are fitted, the backrest 4 is held so that it cannot be removed in the vertical direction and the front-rear direction at both the side connecting portion 23 and the lower connecting portion 65.

  Thus, since the circumferential cam 62 can be set to the bearing rib 61 from the front side, it is not necessary to provide a relief hole in the second back frame 8. Even if a load in the front-rear direction is applied to the circumferential cam 62, the cylinder portion 75 hits the inner surface of the long groove 76, so that no load is applied to the operation tool 40.

  For example, as shown in FIG. 22 (see also FIG. 19), an elastic piece 86 having a lower end as a free end is integrally formed in the front portion of the bearing rib 61 so as to be engaged with the elastic piece 86. While the holes 87 are provided, the cam surfaces 63a, 63b, 63c of the center cam portion 63 of the circumferential cam 62 are provided with projections 88 that fit into the engagement holes 87, respectively. For this reason, when any one of the protrusions 88 is fitted in the engagement hole 87, the user can grasp at an interval that the circumferential cam 62 has been rotated to a predetermined state. That is, the operation tool 40 can be accurately rotated with a click feeling.

  As shown in FIG. 22A, the long grooves 71 of the left and right bearing ribs 61 are open on the lower surface of the second back frame 8. Further, as can be understood from FIG. 20, for example, the bearing holes 81 and 88 into which the operation tool 40 is fitted are long grooves opened to the front. That is, the vertical slot 71 is formed by the longitudinal slot 71 and the bearing holes 81 and 88 are formed. For this reason, the bearing holes 81 and 88 can be formed while performing die cutting relatively easily (the long groove in the front-rear direction is performed by the movement of the main mold, and the long groove 71 in the vertical direction is formed by the slide mold. ).

(9). Others The present invention can be embodied in various ways other than the above embodiment. For example, the present invention can be applied to a chair whose backrest does not rock. Also, the shape and structure of the backrest can be embodied in various ways. For example, it is possible to adopt a structure in which a mesh is stretched on the frame, or a structure in which a soft back plate is exposed without providing a cushion.

Various initial angle adjusting devices can be realized. Further, the operation tool is not limited to a slide type or a rotary type, and a rotary type or the like can also be adopted. It is also possible to adopt a configuration in which an operating tool with a push button is provided at the lower end of the backrest, and the backrest is rotated by moving the operating tool back and forth while holding the unlocked state by pushing the push button. . When a cam is used for the initial angle adjusting device, various cams such as an end face cam can be employed. It is also possible to adjust the initial angle of the backrest steplessly by providing a screw type handle in the initial angle adjusting device. It is also possible to employ a lock mechanism other than a pin or cam.

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

2 Base 3 Seat 4 Backrest 7 1st Back Frame 8 2nd Back Frame 13 2nd Back Frame Base 14, 72 Back Strut 15 Initial Angle Adjuster 18 Back Inner Shell 22 Lumber Support Portion 23 Side Connection Portion 29 Bearing Portion 30 Boss Portions 35 and 64 Lower connecting portion constituting the initial angle adjusting device 40 Operating tool constituting the initial angle adjusting device 45 Lock body constituting the initial angle adjusting device 46 Lock hole 48 Center guard 53 Side guard 54 Side restricting body 62 Initial angle Peripheral cam constituting the adjusting device 65 Lower connecting portion of the backrest 73 Rotating member

Claims (1)

A chair having a seat and a backrest disposed behind the seat, the backrest being attached to a back frame extending rearwardly from below the seat;
The backrest has a lumbar support portion that protrudes forward in a side sectional view to support the lumbar portion of a seated person from behind, and the backrest is rotated around a position at a height position of the lumbar support portion in a side view. An initial angle adjustment device that changes the side view posture of the backrest is provided on the back frame or the backrest so as to be operated while a person is seated, while being connected to the back frame to move.
Chair.

Images