JP2006207756A - Ratchet mechanism and chair - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ratchet mechanism which can prevent an engaging portion and ratchet tooth from wearing mutually, and smoothly perform posture change. <P>SOLUTION: The mechanism comprises: a ratchet tooth J14 which is formed in a first member J1, and has a plurality of engaging recesses J14a, J14b; an engaging portion J3, which is supported to a second member J2, capable of engaging either of a plurality of the engaging recesses J14a, J14b when the second member J2 is located to a normal posture O and a forward folding posture P; and an engaging portion supporting component J22 supported in transferability between an engagement possible position Q, which is prepared in the second member J2, capable of engaging the engaging portion J3 with the engaging recesses J14a, J14b in order and an interference avoiding position R which prevents an interference with the ratchet tooth J14. And, the engaging portion J3 is located to the engaging possible posture Q when the second member J2 is turned to the forward folding posture P from the normal posture O, and to the interference avoiding position R when the second member J2 is turned to the normal posture O from the forward folding posture P simultaneously. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a ratchet mechanism that locks another member pivotally attached to one member so as to be rotatable relative to the one member in a plurality of angular postures, and a chair using the ratchet mechanism. It is about.

  Conventionally, for example, as a ratchet mechanism that locks the backrest with respect to the seat at a plurality of angular postures, a first fitting attached to the seat and a first fitting attached to the backrest and pivotally attached to the first fitting so as to be relatively rotatable. The first bracket is provided with ratchet teeth having a plurality of engagement recesses, while the second bracket is provided with engagement claws that can be engaged with the engagement recesses of the ratchet teeth, and the backrest with respect to the seat The first bracket is rotated with respect to the second bracket in accordance with the operation of inclining by a predetermined angle, and the engagement claw is sequentially engaged with any of the engagement recesses of the ratchet teeth so that the backrest is at a predetermined angle with respect to the seat. Is known (see, for example, Patent Document 1).

In such a ratchet mechanism, the first metal fitting is further provided with a cam plate for controlling the engagement and disengagement between the engagement claw and the engagement recess. Specifically, teeth and engaging recesses are formed on the outer edge of the cam plate at the same pitch as the ratchet teeth, and a closed position where the teeth of the cam plate fill the engaging recesses of the ratchet teeth and an open position where the teeth are opened. A cam plate is swingably provided on the first bracket so that it can be selectively taken. Then, the first metal fitting rotates with respect to the second metal fitting in accordance with the operation of inclining the backrest in the lying posture by a predetermined angle in the direction to stand up with respect to the seat, and the engagement claw takes the release position. The engaging pawls move over the teeth of the cam plate and the ratchet teeth following the operation of engaging the engaging recesses of the ratchet teeth and the engaging recesses of the ratchet teeth and further tilting the seat in the upright direction by a predetermined angle. By engaging the engaging recess of the upper cam plate and the engaging recess of the ratchet teeth, the second bracket is locked with a predetermined inclination with respect to the first bracket, and the backrest is with a predetermined standing posture with respect to the seat. It is configured to lock with. On the other hand, in order to turn the backrest in the standing posture back to the lying down posture, first, the second fitting is rotated relative to the first fitting by first turning the backrest in the standing direction, and the engagement recess of the cam plate. And the engagement recesses of the ratchet teeth and the engagement claws are disengaged, the engagement claws ride on the teeth of the cam plate, and the second metal fitting is rotated and returned in the lying down state in this state. The plate is configured to take the closed position and slide the engaging claw sequentially on the teeth of the cam plate and the teeth of the ratchet teeth.
Actual Kosho 59-20119 (Figs. 2 and 3)

  However, the conventional ratchet mechanism inclines the backrest in the standing posture at a predetermined angle in the direction of lying down, that is, when the second bracket is rotated back with respect to the first bracket, the teeth of the cam plate that take the closed position Since it is necessary to slide the engaging claw sequentially on the teeth and the teeth of the ratchet teeth, there is a problem that the engaging portion and each tooth are easily damaged by friction with each other while the above operation is repeated. As a result, even when the cam plate is positioned at the closing position, the teeth of the cam plate cannot accurately close the engaging recesses of the ratchet teeth, and the engaging claws and the ratchet teeth of the cam plate The second metal fitting cannot be smoothly rotated and returned, and the operation of returning the backrest in the standing posture to the lying posture can be accurately performed. The problem of not being possible also occurs. In addition, since the teeth and engaging recesses are formed on the cam plate at the same pitch as the ratchet teeth, the cam plate is difficult to manufacture and expensive.

  The present invention has been made paying attention to such a problem, and a main purpose thereof is to engage with the engaging portion when the member corresponding to the second metal fitting is rotated and returned from one posture to another posture. An object of the present invention is to provide a ratchet mechanism capable of preventing the ratchet teeth from being worn away from each other and smoothly changing the posture of a member corresponding to the second metal fitting, and a chair provided with the ratchet mechanism.

  In other words, the ratchet mechanism of the present invention locks at least the first member and the second member rotated by a predetermined angle from the first member with the other member pivotally attached to one member. A ratchet tooth provided on one of the one member and the other member and having a plurality of engaging recesses, and held on the other and positioning the other in the first posture and the second posture. An engaging portion that can be engaged with any of the plurality of engaging recesses, and an engageable position that is provided on the other side and that can sequentially engage the engaging portions with the plurality of engaging recesses, and An engagement portion holding element that is held movably between an interference avoidance position that does not interfere with the ratchet teeth, and the engagement portion is moved from the first posture to the second posture. When positioning at the engageable position when rotating In, characterized in that said other member is positioned in the interference avoiding position when pivoting return to the first position from the second position.

  In such a case, the engagement member holding element is used to rotate and return the other member from the second posture to the first posture in a state where the engagement portion is positioned at the interference avoidance position. Since it can prevent a part and a ratchet tooth | gear from rubbing mutually, abrasion of an engaging part and a ratchet part can be suppressed. Furthermore, when the other member is rotated and returned, the engaging portion and the ratchet teeth do not interfere with each other, so that the rotation return operation of the other member can be performed smoothly. Further, by rotating the other member from the first posture to the second posture with the engaging portion positioned at the engageable position using the engaging portion holding element, the engaging portion is moved along the ratchet teeth. Can be reliably engaged with the engaging recess. In addition, since the engaging portion is always held by the engaging portion holding element, a stable holding state of the engaging portion is ensured even when the one member and the other member are relatively rotated. It does not interfere with posture change and is suitable.

  In particular, the engaging portion holding element has a long hole shape and can hold the engaging portion at the engageable position, and a length extending along a direction different from the first holding portion. Since it has a hole shape and has a second holding portion that can hold the engaging portion at the interference avoidance position, and one end portions of the first holding portion and the second holding portion are continuous with each other, Compared with the conventional cam plate, the manufacturing process is simple and the cost can be reduced. Furthermore, the movement between the engageable position of the engagement portion and the interference avoidance position can be performed more smoothly and reliably.

  The same direction as the rotation direction for changing the posture of the other member positioned in the second posture from the first posture to the second posture on any one of the one member or the other member provided with the ratchet teeth Further, the contact portion is brought into contact with the engagement portion positioned at the engageable position with the further rotation operation, and the engagement portion is guided to the interference avoidance position using the engagement portion holding element. If the first contact guide portion is provided, the first contact guide portion can smoothly move the engagement portion from the engageable position to the interference avoidance position. In addition, the engaging portion can be automatically moved from the engageable position to the interference avoidance position by a simple operation of further rotating the other member in the second posture, and the operability is excellent.

  Further, in the process of rotating and returning the other member positioned in the second posture to the first posture on one of the one member or the other member provided with the ratchet teeth, the interference avoiding position is reached. If there is provided a second abutting guide portion that abuts the positioned engaging portion and guides the engaging portion to the engageable position using the engaging portion holding element, this first portion is provided. The two abutment guide portions can smoothly move the engagement portion from the interference avoidance position to the engageable position.

  To ensure the movement between the engageable position and the interference avoidance position of the engaging portion while ensuring a simple structure, either the one member provided with the ratchet teeth or the other member On the other hand, an opening penetrating in the thickness direction of the member is formed, and at least the first contact guide portion, the ratchet teeth, and the second contact guide portion are arranged in this order on the edge of the opening portion. What is necessary is just to form continuously.

  In order to securely engage the engaging portion and the engaging recess when the other member is positioned in the first posture and the second posture, the engaging portion is engaged in the engaging recess. It is preferable to provide the 1st biasing part which biases.

  As a specific embodiment, the engaging portion is a single lock pin that is attached to the one member and the other member so as not to be removable.

  Further, the other member may be locked at a plurality of angular postures in the process of rotating from the first posture to the second posture.

  If a moderation mechanism that stops moderation when the other member is positioned at least in the first and second postures, the other members can be locked more accurately in the first and second postures. it can.

  As a preferred embodiment of the moderation mechanism, a moderator provided on one of the one member or the other member and a plurality of modes provided on the other at a predetermined pitch and capable of temporarily holding the moderator. The thing comprised from the child holding | maintenance part is mentioned. In this case, the one member and the other member are both substantially plate-shaped, and either the one member or the other member provided with the moderation element is penetrated in the thickness direction. The other member provided with the moderator holding portion is provided in a pair at a position where the one member can be sandwiched. It is preferable.

  In order to reliably stop the moderation when the other member is positioned in the first posture and the second posture, the other member provided with the moderator holding portion so as to hold the moderator in the moderator holding portion. What is necessary is just to provide the 2nd urging | biasing part which urges | biases a member and the said one member which distributes the said moderation element in the direction which mutually approaches. In this case, a shaft hole is formed in the one member and the other member, and a nut is fastened with an elastic member disposed on at least one end of the shaft member continuously inserted through the shaft hole. It is desirable that the member and the other member are elastically urged in a direction in which they contact or approach each other, and this elastic member functions as the second urging portion.

  On the other hand, as a chair to which such a ratchet mechanism is applied, the backrest includes a first backrest portion that is partitioned at a predetermined height position and located on the lower side, and a second backrest portion that is located on the upper side. A normal posture in which the second backrest portion is at least substantially linear with the first backrest portion, and a folding posture in which the first backrest portion is folded forward or backward from the first posture from the normal posture. And the folding device is configured using the ratchet mechanism, the second backrest portion is positioned in the normal posture by positioning the other member of the ratchet mechanism in the first posture, What makes the 2nd backrest part be positioned in the said bending attitude | position is mentioned by positioning the said other member in a 2nd attitude | position. In this case, if the one member is attached to the upper end portion of the first back frame constituting the first back portion and the other member is attached to the lower end portion of the second back frame constituting the second back portion. Good.

  As described above, according to the present invention, the other member is rotated from the first posture to the second posture in a state where the engaging portion is positioned at the engageable position using the engaging portion holding element. Since it is configured, the engaging portion can be reliably engaged with the engaging recess while following the ratchet teeth, and the engaging portion is positioned at the interference avoidance position using the engaging portion holding element. Thus, the other member is configured to rotate and return from the second posture to the first posture, so that the engaging portion and the ratchet teeth are prevented from being damaged by friction with each other. The motion return operation can be performed smoothly.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  The ratchet mechanism J according to the present embodiment is applied to, for example, a chair X shown in FIG. First, the chair X will be described.

  As shown in FIGS. 1 to 3, the chair X includes a base 1, a seat 2 including a seat body 21 and an auxiliary seat 22 disposed on the front end side of the seat body 21, and a body seat that supports the seat body 21. On the front side of the upper end of the backrest 4, the seat support 3 including the support 31 and the auxiliary seat receiver 32 that supports the auxiliary seat 22, the backrest 4 including the lower backrest portion 41, the middle backrest portion 42, and the upper backrest portion 43. A headrest 5 arranged, a legrest 6 pivotally attached to the front end portion of the seat 2, a pair of left and right armrests 7 arranged on the upper end sides of the left and right ends of the base 1, and an auxiliary work table supported by the base 1 8 and so on. In FIG. 2 and subsequent figures, the auxiliary work table 8 is omitted for the sake of drawing.

  Hereinafter, each part will be described.

  The base 1 includes a metal base main body 11 and a base cover portion 12 that is detachably attached to the base main body 11.

  More specifically, the base body 11 includes a left base portion 111 and a right base portion 112 that form a pair of left and right sides, and a bottom base portion 113 that connects the lower end portions of both the base portions 111 and 112.

  More specifically, the left base portion 111 includes a lower base pipe 111a extending in a substantially straight shape when viewed from the side, and an upper base pipe that is arranged to face the upper side of the lower base pipe 111a and has a substantially partial arc shape when viewed from the side. 111b, and five upper and lower connection pipes 111c that connect the lower base pipe 111a and the upper base pipe 111b. In this embodiment, each of the pipes 111a, 111b, and 111c is formed using square pipes. Yes. Since the right base portion 112 has the same configuration as the left base portion 111, the description thereof is omitted.

  The bottom base portion 113 is a front connection base formed using a square pipe that connects the second and fourth upper and lower connection pipes 111c from the front side among the five upper and lower connection pipes 111c of the base portions 111 and 112. A pipe 113a and a rear connection base pipe 113b are provided. In this embodiment, reinforcing members 113c that are substantially U-shaped in a plan view and substantially trapezoidal in a front view are provided at both ends of each of the connecting base pipes 113a and 1113b, and the reinforcing member 113c and the upper and lower connecting pipes 111c Are fastened using screws or the like.

  The base cover part 12 is obtained by covering a wooden base cover part body having an outer dimension that substantially overlaps with the left base part 111 or the right base part 112 when viewed from the side, with a cloth base cover part covering part.

  The seat body 21 constituting the seat 2 includes a plate-like seat plate 211 having a substantially rectangular shape in plan view, and a seat cushion 212 formed using a material having elasticity such as urethane disposed above the seat plate 211, The seat cushion 212 is formed of a cloth seat body cover portion 213 that covers the surface of the seat cushion 212 and is fastened with a tacker or the like on the back surface side of the seat plate 211. It is attached.

  As shown in the figure, the auxiliary seat 22 constituting the seat 2 is made of a plate-like auxiliary seat plate 221 having a substantially rectangular shape in plan view, and a material having elasticity such as urethane disposed above the auxiliary seat plate 221. An auxiliary seat cushion 222 formed by using the cloth, and an auxiliary seat cover portion 223 made of cloth covering the surface of the auxiliary seat cushion 222 and fastened with a tacker or the like on the back side of the auxiliary seat plate 221. The back surface is attached to the auxiliary seat receiver 32. The legrest 6 is rotatably attached to the lower end portion on the front end side of the auxiliary seat 22 via a mounting bracket 24. In the present embodiment, the depth dimension of the auxiliary seat 22 is set smaller than the depth dimension of the seat body 21, and the thickness dimension of the auxiliary seat 22 is set to be substantially the same as the thickness dimension of the seat body 21. More specifically, the wall thickness dimension at the rear end portion of the auxiliary seat 22 is set to be substantially the same as the wall thickness dimension of the seat body 21, and the wall thickness dimension in the region from the rear end portion to the center portion is gradually increased. In addition, the thickness dimension of the region extending from the center portion to the front end portion is set slightly larger than the thickness dimension of the seat body 21.

  The seat 2 including the seat main body 21 and the auxiliary seat 22 further includes a connecting portion 23 (not shown) that connects the lower end portion at the front end portion of the seat main body 21 and the upper end portion at the rear end portion of the auxiliary seat 22 ( (Refer FIG.6 (b)). The connecting portion 23 is a thin cushioning material formed using a material having elasticity such as urethane, and a cloth connecting cover portion is covered with the base end portion of the connecting portion at the lower end of the front end portion of the seat body 21. The front end portion is sewn to the upper end portion of the rear end portion of the auxiliary seat 22. When the connecting portion 23 is positioned at the second use position in which the auxiliary seat 22 is positioned at a lower position than the seat surface of the seat main body 21, the front end portion of the seat main body 21 and the rear end portion of the auxiliary seat 22 are provided. Take a lying posture that extends between and.

  The body seat receivers 31 constituting the seat support body 3 are provided in a pair of left and right so as to be supported by the base 1 and to support the seat body 21, and between the front end portions of the pair of body seat receivers 31 and The main body seat receiving front side connection pipe 31a and the main body seat receiving rear side connection pipe 31b connecting the rear ends have effective support strength and connection strength.

  More specifically, these body seat receivers 31 are respectively disposed inside the left base portion 111 and the right base portion 112, and are disposed along the side edges of the seat body 21 and the seat body 21 and A main body seat receiving part 311 having a substantially rectangular shape in a plan view that contacts and supports the main body seat receiving part 311, a main body seat receiving part 312 hanging from the inner edge of the main body seat receiving part 311, and the main body seat receiving part 312. A main body seat receiving bulging portion 313 that bulges to the front end side and has a substantially triangular shape in side view, and a main body seat receiving protrusion that protrudes upward from the rear end portion of the main body seat receiving main portion 312. Part 314, and these parts are formed by plastic deformation of a sheet metal material or the like. The front end of each body seat receiving bulging portion 313 can rotate via the spacer 313a to the foremost vertical connection pipe 111c among the five vertical connection pipes 111c of the left base portion 111 or the right base portion 112 facing each other. It is comprised so that it may be supported by.

  The auxiliary seat receiver 32 constituting the seat support 3 is placed on the back surface of the auxiliary seat 22 and contacts the front half of the back surface side of the seat body 21 when the auxiliary seat 22 is positioned at a first use position described later. A backing portion 321 that is in contact with or close to the backing portion 321 and a pair of hanging pieces 322 that are suspended from both side edges of the backing portion 321 are integrally provided by plastic deformation of a sheet metal material or the like.

  The lower backrest portion 41 that constitutes the backrest 4 includes a pair of left and right lower backrest vertical frame portions 411 and a lower backrest horizontal frame pipe 412 that is placed horizontally between upper end portions of the lower backrest vertical frame portions 411. is there. The lower backrest vertical frame portion 411 includes a lower back frame base portion 411a having a substantially triangular shape in side view, and a lower back frame main body 411b that is supported by a substantially central portion of the lower back frame base portion 411a and extends obliquely rearward. The lower back frame base part 411a is formed by plastic deformation or the like of a sheet metal material, and has a front end part rotatably connected to a rear end part of the main body seat receiver 31.

  The middle backrest portion 42 constituting the backrest 4 includes a pair of left and right middle backrest vertical frame pipes 421, and a middle backrest upper horizontal frame pipe 422 horizontally disposed between the upper end portions and the lower end portions of the middle backrest vertical frame pipes 421. And a lower horizontal frame pipe 423 with an intermediate backrest.

  The upper backrest portion 43 constituting the backrest 4 is a front surface in which a pair of left and right upper backrest vertical frame pipes 431a and an upper backrest upper horizontal frame pipe 431b formed by connecting the upper end portions of the respective upper backrest vertical frame pipes 431a are integrally formed. An upper back frame pipe main body 431 having a substantially portal shape, an upper back middle horizontal frame pipe 432 laid between the center portions of the upper back vertical frame pipes 431a, and the upper back middle frame pipe 432 and upper back. A pair of slide rails 433 connecting the upper horizontal frame pipe 431b is provided.

  A back cushion 44 formed using a material having elasticity, such as urethane, is arranged on the front side of each frame pipe of each of the backrest portions 41, 42, 43, and each of the backrest portions 41, 42, 43 is provided. It is covered with a cloth backrest cover 45.

As shown in FIG. 4, the headrest 5 includes a pillow base 51 that is attached to the slide rail 433 of the upper backrest portion 43 via a mounting bracket 55, a head cushion 52 that is provided on the front side of the pillow base 51, and the head cushion. The pillow base 51 is provided with a pillow base main body 511 and both side ends of the pillow base main body 511. The pillow base 51 includes a pillow cover 53 that covers the pillow 52 and a washable cover 54 that further covers the pillow cover 53. Each is provided with a pair of movable base bodies 512 that are provided via hinges 51h and can change the angle within a predetermined angle range with respect to the pillow base body 511, and will be described later on both side ends of the pillow base body 511. A hook portion 511a that can be hooked by the pull-in rubber string 531 is formed.

  The head cushion 52 includes a head cushion main body 521 supported by the pillow base main body 511, and a pair of movable cushion bodies 522 disposed on both side ends of the head cushion main body 521 and supported by the movable base body 512. The head cushion main body 521 and the movable cushion body 522 each have a substantially partial arc shape in cross-sectional view that bulges forward, and are integrally attached by sewing together at appropriate places.

  The pillow cover 53 covers the head cushion 52 in a state where the head cushion body 521 is exposed on the back side, and a pull-in rubber that can circulate the head cushion body 521 and the pillow base body 511 on the inner surface side. A string 531 is provided on the inner surface side. Then, in a state where the head cushion 52 and the pillow base 51 are covered by the pillow cover portion 53, the pull-in rubber string 531 is hooked on the hook portion 511 a of the pillow base main body 511 so as to go around the head cushion main body 521 and the pillow base main body 511. At the same time, the hook-and-loop fastener 53f provided at the upper and lower ends of the pillow cover 53 and the hook-and-loop fastener 511f provided at the upper and lower ends of the pillow base body 511 are fastened to each other.

  The washable cover portion 54 covers the outer surface of the pillow cover portion 53 using the hook-and-loop fastener 54f in a state where the pillow base body 511 is exposed on the back side, and a resin button (male) provided on the upper end portion. ) 54 b is attached to the pillow cover portion 53 by being fastened to a resin button (female) 53 b provided at the upper end portion of the pillow cover portion 53.

  The headrest 5 having such a configuration is attached to the pair of slide rails 433 of the upper backrest portion 43 via the mounting bracket 55 and is set to be slidable along the height direction of the backrest 4. By applying an operation force to bend the both ends inward toward the center of the headrest 5, the movable base body 512 changes the angle with respect to the pillow base body 511 using the hinge 51h. The movable cushion body 522 changes in angle with respect to the head cushion body 521 in conjunction with the change in angle. As described above, the headrest 5 of the present embodiment is set so that the angle of both side ends can be adjusted so that the seated person's head can be supported in a stable state.

  The legrest 6 includes two legrest portions 61 and 62 including a distal end side legrest portion 61 and a proximal end side legrest portion 62 that operate in conjunction with each other. In the standing state, substantially the entire distal leg rest 61 is accommodated in the proximal leg rest 62, while in the horizontal state, the distal leg rest 61 is substantially proximal. It is configured to be exposed from the portion 62.

  The armrest 7 is connected to the armrest main body 71 having a substantially arc shape in a side view, the front end portion and the rear end portion of the armrest main body 71, and supported by the upper base pipe 111b of the left base portion 111 and the right base portion 112. While providing the armrest front support part 72 and the armrest rear support part 73, the armrest cover part 74 is provided in the position which covers the upper end part of the armrest main body 71 substantially. In the present embodiment, the armrest body 71, the armrest front support portion 72, and the armrest rear support portion 73 are integrally formed by aluminum die casting, while the armrest cover portion 74 is formed of wood. Is not disturbed by the same material.

  The auxiliary workbench 8 includes a thin plate-like auxiliary workbench main body 81 having a substantially rectangular shape in plan view, an auxiliary workbench arm portion 82 provided on the back surface of the auxiliary workbench main body 81, and the auxiliary workbench main body 81. The auxiliary work table arm 82 is rotatably supported in a horizontal plane, and the auxiliary work table support column 83 is supported by the front end of the right base 112. . In this embodiment, the width of the auxiliary workbench main body 81 is made of a wooden material that substantially matches the width of the seat main body 21, but the dimensions and materials of each part can be appropriately changed according to the embodiment. is there.

  The chair X according to the present embodiment composed of each part as described above further includes an interlocking rearward tilting device that performs a rearward tilting operation while interlocking the seat 2 and the backrest 4 corresponding to the rearward tilting operation of the main body seat receiver 31. A and the first use position in which the seat surface of the auxiliary seat 22 is substantially coincident with the seat surface of the seat body 21 and the second use in which the seat surface of the auxiliary seat 22 is positioned lower than the seat surface of the seat body 21. The leg rest 6 is rotated and extended by using a common actuator (not shown) and a lifting / lowering device B for moving the auxiliary seat 22 up and down with respect to the seat body 21 between the positions and a substantially horizontal horizontal position. Leg rest drive unit C that is reduced to a standing state that is reduced while being rotated or rotated, and a backrest device that causes the backrest part 42 to bend backward from the normal posture with respect to the lower backrest part 41. D against the middle back 42 And it includes a front folding device E for causing breakage before the upper backrest portion 43 in front of the normal position Te.

  And the chair X of this embodiment selects one or more from the interlocking backward tilting apparatus A, the raising / lowering moving apparatus B, the legrest part drive apparatus C, the backrest apparatus D, and the front folding apparatus E, and operates them appropriately. Thus, for example, a normal sitting posture (FIG. 5 (a)) that is optimal for upright work, a cross-legged posture (FIG. 5 (b)), and a posture that is optimal for reclining work (FIG. 6 (e)). , Postures optimal for various stretching (FIGS. 5C, 6D and 6F), postures optimal for nap (FIG. 6G), postures optimal for sleep Realize back angle and seat angle corresponding to various usage modes of seated person such as (Fig. 6 (h)), and favorably support the intelligent activities of home workers, and refresh effectively between work And improve the effect of resting in a short time Are you.

  Further, the backrest 4 may be provided with a lumbar support device G for supporting the working posture.

  As a specific aspect of the lumbar support device G, for example, as shown in FIG. 7 (where FIGS. (A) and (b) are respectively a plan view and a front view of the lumbar support device G), for example, Four movable bars G1 which are thin and have a substantially partial arc shape in cross section, and a base plate which is arranged on the lower end side of the lowermost movable bar G1 and which is attached to the lower backrest horizontal frame pipe 412 not shown in the figure G2, a pair of joint members G3 connecting both ends of adjacent movable bars G1 and both ends of the lowermost movable bar G1 and the base plate G2, and the uppermost movable bar G1 are drawn toward the base plate G2. The lumbar support operation unit G4 is provided, and by operating the lumbar support operation unit G4 and pulling the uppermost movable bar G1 toward the base plate G2, the four movable bars G1 are formed. Flexes overall in the direction of the arrow Ga shown in FIG. 6 (a), it can be mentioned those so as to function as lumbar support for supporting the lumbar region of the seated person.

  Further, at this time, the lumbar support operating portion G4 is attached to the uppermost movable bar G1 with a cam member G41 having a substantially triangular shape and a central portion rotatably supported by the base plate G2 and one end side G42a. And the other end side G42b is supported by the one end G41a of the cam member G41 so as to be rotatable, and the thin plate-like movable bar pulling member G42 is supported by the base plate G2 at two locations G2x and G2y, and the lumbar support is adjusted at one end side. For example, the lumbar support operation portion G4 is not limited to this configuration, but includes the screw rod G43 that includes the grip G431 and the other end G41b of the cam member G41 at the other end.

  Thus, in the present embodiment, the forward folding device E is configured using a ratchet mechanism J described in detail below.

  As shown in FIGS. 2, 3, 8 to 12, the ratchet mechanism J according to the present embodiment has a middle backrest that constitutes the middle backrest portion 42 (corresponding to the “first backrest portion” in the present invention). A first member J1 having a base end attached to an upper end portion of a frame pipe 421 (corresponding to "first back frame" in the present invention) and an upper backrest portion 43 (corresponding to "second backrest portion" in the present invention) A second member J2 having a base end portion attached to the lower end portion of the upper backrest vertical frame pipe 431a (corresponding to the “second backrest frame” in the present invention) and a distal end portion pivotally attached to the first member J1. The second member J2 is made up of a normal posture (O) in which the second member J2 and the first member J1 are substantially linear (corresponding to the “first posture” in the present invention), and a normal posture (O ) First member J It is to lock out (corresponding to the "second position" in the present invention) rotated by a predetermined angle is not the pre-folded position (P) forward relative.

  The ratchet mechanism J includes a ratchet tooth J14 formed in the first member J1 and having a first engagement recess J14a and a second engagement recess J14b, and is held by the second member J2 and holds the first member J1 in a normal posture ( O) and a single engagement portion J3 that can be engaged with any one of the engagement recesses J14a and J14b when positioned in the forward bending posture (P), and the engagement portion J3 provided on the second member J2. Engaging portion holding element J22 movably held between an engageable position (Q) that can be sequentially engaged with the engaging recesses J14a and J14b and an interference avoiding position (R) that does not interfere with the ratchet teeth J14. It is equipped with.

  As shown in FIG. 9A, the first member J1 has a substantially flat plate shape, has a shaft hole J11 penetrating in the thickness direction in the center portion, and has a substantially fan shape in side view at the tip portion. A tip bulging portion J12 is provided, and an opening J13 that penetrates the tip bulging portion J12 in the thickness direction and has a substantially similar shape smaller than the tip bulging portion J12 is formed. Of the edge of the opening J13, a first engagement recess that can be engaged with the engagement portion J3 when the second member J2 is positioned in the normal posture (O) in the arc closer to the shaft hole J11. Ratchet teeth J14 having J14a and a second engagement recess J14b that can be engaged with the engagement portion J3 when the second member J2 is positioned in the forward folding posture (P) are provided. In the present embodiment, a first imaginary straight line La connecting the center portion of the first engaging recess J14a and the center portion of the shaft hole J11 is defined as a center line L1 (hereinafter referred to as “first member”) along the longitudinal direction of the first member J1. The second virtual straight line Lb connecting the center of the second engagement recess J14b and the center of the shaft hole J11 is approximately 15 degrees with respect to the first virtual straight line La. It is set to make. The ratchet tooth J14 allows the engagement portion J3 to move from the first engagement recess J14a to the second engagement recess J14b between the first engagement recess J14a and the second engagement recess J14b and is engaged. A tooth portion J14c that restricts movement of the portion J3 from the second engagement recess J14b to the first engagement recess J14a is provided. Further, of the edges of the opening J13, a straight line is formed toward one end of an arc J15 far from the second engagement recess J14b of the ratchet tooth J14 to the shaft hole J11 (hereinafter referred to as “outer arc portion J15”). The first side edge J16 extending in the direction is inclined by a predetermined angle (approximately 25 degrees in the present embodiment) in a direction away from the first member center line L1 with respect to the second virtual straight line Lb (approximately 25 degrees in the present embodiment) A second side edge portion J17 extending linearly from the engagement recess portion J14a toward the other end of the outer arc portion J15 is set to be parallel to the first member center line L1. The first member J1 is provided with through holes J18 facing each other across the shaft hole J11 on the first member center line L1 and the second imaginary straight line Lb, and the moderation described later within these four through holes J18. The moderator J81 (shown with a pattern shown in FIGS. 9 and 10) constituting the mechanism J8 can move freely.

  As shown in FIG. 9B, the second member J2 has a substantially flat plate shape, has a shaft hole J21 penetrating in the thickness direction at the tip portion, and is substantially L-shaped in side view at the center portion. The engaging portion holding element J22 which is a slot is formed. The engaging portion holding element J22 has a long hole-shaped first holding portion J221 that can hold the engaging portion J3 in the engageable position (Q), and a direction substantially orthogonal to the first holding portion J221. And a second holding portion J222 capable of holding the engaging portion J3 at the interference avoidance position (R). The base ends of the first holding portion J221 and the second holding portion J222 are connected to each other. It is a continuous one. In the present embodiment, the center line along the longitudinal direction of the first holding portion J221 is matched with the center line L2 along the longitudinal direction of the second member J2 (hereinafter referred to as “second member center line L2”), The distal end portion of the second holding portion J222 is extended rearward from the base end portion of the first holding portion J221. In addition, the second member J2 forms a pair of first recesses J23 that are recessed from other parts at positions facing the second member center line L2 across the shaft hole J21, and the shaft hole J21 is formed in the second member J2. A pair of second recesses J24 and a pair of third recesses that are recessed from other parts on the virtual circle M passing through the pair of first recesses J23 at the center and corresponding to each other across the shaft hole J21. J25 is formed. The angle formed by the third virtual straight line Lc passing through each second recess J24 and the second member center line L2 is the angle formed by the second virtual straight line Lb of the first member J1 and the first virtual straight line La (this embodiment). The fourth virtual straight line Ld passing through each third recess J25 is set to be the target of the third virtual straight line Lc with the second member center line L2 as the center. . The 1st recessed part J23, the 2nd recessed part J24, and the 3rd recessed part J25 play the role as the moderator holding | maintenance part of this invention which can hold | maintain the moderator J81 temporarily.

  In the present embodiment, the second member J2 having such a configuration is provided as a pair at a position where the first member J1 can be sandwiched (see FIG. 8). The first member J1 and the pair of second members J2 can be rotated relative to each other by fastening a nut J5 to the tip of the shaft member J4 that is inserted through the shaft holes J11 and J21 of the members J1 and J2. It is pivotally attached. In this embodiment, a bolt is applied as the shaft member J4. Further, as shown in FIG. 11A, which is an end view taken along line AA in FIG. 10, three disc springs J6 are interposed between the head portion J41 of the shaft member J4 and one of the second members J2. I am letting. The disc spring J6 elastically biases the first member J1 and the pair of second members J2 in a direction to abut or approach each other.

  On the other hand, the engaging portion J3 can be sequentially engaged with the engaging recesses J14a and J14b of the ratchet teeth J14 provided on the first member J1 while being held by the engaging portion holding element J22 of the second member J2. In this embodiment, a substantially cylindrical lock pin is used as the engaging portion J3 (shown with a pattern in FIGS. 9 and 10). In addition, the engaging part J3 is provided with a locking collar J31 that prevents the engaging part J3 from being pulled out from the first member J1 and the second member J2 at both ends thereof.

  Further, the ratchet mechanism J includes a first urging portion J7 that urges the engaging portion J3 in a direction to engage the engaging recesses J14a and J14b, and the second member J2 in a normal posture (O) and a forward bent posture ( And a moderation mechanism J8 that stops moderation when positioned at P).

  In the present embodiment, a coil spring in which the upper end is hooked to one end of the engaging portion J3 and the lower end is hooked to one end of the shaft member J4 is applied as the first biasing portion J7 (see FIG. 10).

  The moderation mechanism J8 includes a total of four moderation elements J81 that can move freely in each through hole J18 provided in the first member J1, as shown in FIG. And a pair of the first concave portion J23, the second concave portion J24, and the third concave portion J25 that are provided at a predetermined pitch on the second member J2 and can temporarily hold the moderator J81. The moderation element J81 is a rigid body having a substantially spherical shape, and a part of the moderation element J81 is set so as to be selectively fitted and engaged with the first recess J23, the second recess J24, or the third recess J25. Further, three disc springs J6 interposed between the head portion J41 of the shaft member J4 and one of the second members J2 contact or approach the first member J1 and the pair of second members J2. By elastically urging in the direction to be moved, the moderation element J81 is held between the second members J2 while being in contact with or close to the second members J2 facing each other. As a result, when the four moderators J81 are positioned at the positions facing the first recess J23 and the second recess J24 or the positions facing the first recess J23 and the third recess J25, the four moderators J81 are located. Are simultaneously fitted into the first concave portion J23 and the second concave portion J24 facing each other, or the first concave portion J23 and the third concave portion J25, respectively. That is, the four moderation elements J81 are simultaneously fitted in four of the six recesses. Thereby, it is suppressed that the 1st member J1 and the 2nd member J2 shake mutually. Thus, the disc spring J6 brings the first member J1 and the second member J2 closer to each other so as to hold the moderation element J81 in any of the first recess J23, the second recess J24, or the third recess J25. It functions as a second urging portion of the present invention that urges in the direction.

  Next, the operation and action of the ratchet mechanism J having such a configuration will be described with reference to FIG.

  First, when the second member J2 is positioned in the normal posture (O) (see FIG. 5A), the distal end portion of the first holding portion J221 of the engaging portion holding element J22 provided on the second member J2. And the second engaging recess J14b of the ratchet teeth J14 formed on the first member J1 substantially coincide with each other, and the engaging portion J3 is held in the first holding portion J221 of the engaging portion holding element J22 in the second state. Engaging with the engaging recess J14b, the posture change of the second member J2 relative to the first member J1 is restricted. Further, each moderator J81 is temporarily held by elastic engagement with the pair of first recess J23 and third recess J25.

  On the other hand, in order to position the second member J2 taking the normal posture (O) in the forward folding posture (P), an operating force for rotating the second member J2 forward about the shaft member J4 is applied. With this operating force, the engagement state between the engagement portion J3 and the second engagement recess J14b is released over time, and the engagement state between the moderation element J81, the first recess J23, and the third recess J25 is also increased. The engagement portion J3 rides on the tooth portion J14c of the ratchet tooth J14 while being held by the first holding portion J221 of the engagement portion holding element J22 (see FIG. 5B). At this time, as shown in FIG. 13, since the longitudinal dimension of the first holding part J221 is set larger than the sum of the protruding dimension of the tooth part J14c and the diameter of the engaging part J3, the engaging part J3 is In a state where it rides on the tooth portion J14c, the engaging portion J3 is held in the first holding portion J221, and the engaging portion J3 does not move to the second holding portion J222. When the second member J2 is subsequently rotated forward, it engages with the first engaging recess J14a that coincides with the tip of the first holding portion J221 (see FIG. 10 (c)). At this time, the engaging portion J3 is urged toward the shaft member J4 by the first urging portion J7 and reliably engages with the first engaging recess J14a. As described above, when the second member J2 is rotated from the normal posture (O) to the forward bent posture (P), the engaging portion J3 held by the first holding portion J221 of the engaging portion holding element J22 is 2 It is located in the engageable position (Q) which can be sequentially engaged with the engagement recessed part J14b and the 1st engagement recessed part J14a. Further, at substantially the same time as the engaging portion J3 engages with the first engaging recess J14a, each moderator J81 elastically engages with the pair of first recesses J23 and the pair of second recesses J24 and is temporarily held. . As a result, the second member J2 is positioned in the forward bending posture (P) inclined by a predetermined angle (approximately 15 degrees in the present embodiment) with respect to the first member J1, and in this state, the tooth portion of the ratchet tooth J14 Since the movement of the engaging portion J3 from the first engaging concave portion J14a to the second engaging concave portion J14b is restricted by J14c, the second member J2 does not rotate unexpectedly rearward and in a stable state. Locked.

  On the other hand, in order to position the second member J2 taking the forward bending posture (P) in the normal posture (O), first, an operating force for further rotating the second member J2 forward is applied. Due to this operating force, the engagement state between the engagement portion J3 and the first engagement recess J14a is released over time, and the elastic engagement between the moderation element J81, the first recess J23, and the second recess J24 is also achieved. The first holding of the engaging portion holding element J22 is released along the first side edge J16 while the engaging portion J3 is in contact with the first side edge J16 of the opening J13 formed in the first member J1. When the second member J2 is further moved forward from the distal end portion of the portion J221 to the base end portion, the second member J2 moves to the second holding portion J222 of the engaging portion holding element J22 (see FIG. 4D). And each part (The front-end | tip part of the 2nd holding part J222, the 1st side edge part J16) in the state where the engaging part J3 was pinched | interposed between the front-end | tip part of the 2nd holding | maintenance part J222, and the 1st side edge part J16. By abutting, further forward rotation of the second member J2 is restricted. Next, when an operation force for rotating the second member J2 in the reverse direction, that is, backward, is applied, the opening J13 is held in a state where the engaging portion J3 is held at the distal end portion of the second holding portion J222. While moving inside, the second side edge J17 of the opening J13 abuts against the second side edge J17 (see (e) in the same figure), and is pushed out from the distal end portion of the second holding portion J222 to the proximal end portion. The urging force of the first urging portion J7 moves along the portion J17 from the proximal end portion of the first holding portion J221 to the distal end portion, and engages with the second engaging recess J14b of the ratchet teeth J14 (FIG. a)). Thus, when the second member J2 is rotated and returned from the forward folding posture (P) to the normal posture (O), the engaging portion J3 held by the second holding portion J222 of the engaging portion holding element J22 is It is positioned at the interference avoidance position (R) that does not interfere with the ratchet teeth J14 (particularly the tooth portion J14c). Further, at substantially the same time as the engaging portion J3 engages with the second engaging recess J14b, each moderator J81 elastically engages with the pair of first recess J23 and the pair of third recess J25, respectively, and is temporarily held. The Accordingly, the second member J2 is not unexpectedly rotated forward and backward with respect to the first member J1, and the second member J2 is locked in the normal posture (O) in a stable state. When changing the posture of the second member J2 from the forward bending posture (P) to the normal posture (O), the first side edge J16 of the opening J13 further moves the second member J2 positioned in the forward bending posture (P). Along with the operation of rotating forward, the engaging portion J3 is held in the first holding portion J221 of the engaging portion holding element J22 and comes into contact with the engaging portion J3 positioned at the engageable position (Q), and the engaging portion J3. Is moved to the second holding portion J222 of the engaging portion holding element J22 to function as the first contact guide portion of the present invention that guides to the interference avoidance position (R). On the other hand, when the posture of the second member J2 is changed from the forward bending posture (P) to the normal posture (O), the second side edge J17 of the opening J13 is moved to the second holding portion J222 of the engaging portion holding element J22. The engaging position (R) is brought into contact with the engaging portion J3 positioned at the interference avoiding position (R), and the engaging portion J3 is moved to the first holding portion J221 of the engaging portion holding element J22. It functions as the second contact guide portion of the present invention for guiding to Q).

  By interposing the ratchet mechanism J having such a configuration between the middle backrest portion 42 and the upper backrest portion 43, the ratchet mechanism J causes the upper backrest portion 43 to be connected to the upper backrest portion 43 and the middle backrest portion 42. Functions as a pre-folding device E that locks between a normal posture (S) that is substantially linear and a front-folding posture (T) that is forward-folded forward relative to the middle backrest portion 42 from the normal posture (S). .

  Specifically, the ratchet mechanism J is provided between the middle backrest portion 42 and the upper backrest portion 43 in a pair of left and right, and the base end portion of the first member J1 is used as the middle backrest vertical frame of the middle backrest portion 42. The upper end portion of the pipe 421 is inserted, and the base end portion of the second member J2 is inserted into the lower end portion of each upper backrest vertical frame pipe 431a of the upper backrest portion 43, and is fastened using screws or the like not shown. Yes.

  Therefore, in order to change the posture of the upper backrest portion 43 taking the normal posture (S) to the forward folded posture (T), an operating force for pushing the upper backrest portion 43 forward is applied. As a result, the second member J2 rotates forward with respect to the first member J1, and is locked in the forward folding posture (P) through the above-described operation. As a result, the relative relationship between the first member J1 and the second member J2 Corresponding to the angle, the upper backrest portion 43 is locked in the forward bending posture (T) inclined at a predetermined angle (approximately 15 degrees in the present embodiment) with respect to the middle backrest portion 42 (see FIG. 12A).

  In addition, in order to change the posture of the upper backrest portion 43 taking the forward bending posture (P) to the normal posture (O), first, an operation force that pushes the upper backrest portion 43 further forward is applied. As a result, the second member J2 rotates further forward with respect to the first member J1, and the engaging portion J3 is moved from the first holding portion J221 to the second holding portion of the engaging portion holding element J22 through the above-described operation. Move to J222. Next, by applying an operation force that causes the upper backrest portion 43 to pivotally return to the rear, the second member J2 pivots back to the first member J1, and the normal posture (O) through the above-described operation. As a result, the upper backrest 43 is locked in the normal posture (O). By the simple operation as described above, the upper backrest portion 43 can be locked in the normal posture (O) and the forward bent posture (P), and the upper backrest portion 43 is appropriately set in accordance with the use mode of the seated person. The posture can be changed.

  As described above, the ratchet mechanism J according to the present embodiment holds the engaging portion J3 on the engaging portion holding element J22 when the second member J2 is rotated from the normal posture (O) to the forward folded posture (P). Since the engagement portion J3 stably held by the engagement portion holding element J22 is positioned along the ratchet teeth J14, the engagement recesses J14a and J14b are surely placed in the engaged state (Q). In addition to being able to be engaged, when the second member J2 is rotated and returned from the forward folding posture (P) to the normal posture (O), the engaging portion J3 is held by the engaging portion holding element J22 and Since it is positioned at the interference avoidance position (R), the engaging portion J3 stably held by the engaging portion holding element J22 does not interfere with the ratchet teeth J14, and the engaging portion J3 and the ratchet teeth J14 are mutually connected. Wear damage Not only to prevent Rukoto, it is possible to obtain a good operation feeling, it is possible to perform the position change of the second member smoothly.

  In particular, the engaging portion holding element J22 has a long hole shape and can hold the engaging portion J3 in the engaging position (Q), and the first holding portion J221 is along a different direction. And a second holding portion J222 that can hold the engaging portion J3 at the interference avoidance position (R), and one end portions of the first holding portion J221 and the second holding portion J222 are connected to each other. Since it is continuous, the configuration of the engagement portion holding element J22 is simplified, and the movement between the engagement possible position (Q) and the interference avoidance position (R) of the engagement portion J3 is smoother and It can be done reliably. Further, the engagement portion J3 positioned at the engageable position (Q) or the interference avoidance position (R) is held by the first holding portion J221 or the second holding portion J222, so that the engagement portion J3 can be stably operated. Can be realized.

  Further, the second member J2 positioned in the forward bending posture (P) can be engaged in the same direction as the rotation direction when the posture is changed from the normal posture to the forward bending posture, that is, the operation of rotating forward. A function as a first abutment guide portion that abuts the engagement portion J3 positioned at the position (Q) and guides the engagement portion J3 to the interference avoidance position (R) using the engagement portion holding element J22. Since the first side edge portion J16 is provided on the first member J1, the first side edge portion J16 moves the engagement portion J3 from the engageable position (Q) to the interference avoidance position (R) before. The engagement portion J3 can be automatically moved from the engageable position (Q) to the interference avoidance position (R) with a simple operation of further rotating the second member J2 in the folded posture (P). Can be made and has excellent operability.

  In addition, when the second member J2 positioned in the forward bending posture (P) is rotated back to the normal posture (O), the second member J2 comes into contact with the engaging portion J3 positioned in the interference avoidance position (R), and Since the second side edge portion J17 that functions as a second contact guide portion that guides the engagement portion J3 to the engageable position (Q) using the engagement portion holding element J22 is provided, this second side The edge J17 can automatically move the engagement portion J3 from the interference avoidance position (R) to the engageable position (Q) in accordance with the operation of rotating and returning the second member J2. The ease of operation is further improved.

  Moreover, since the first side edge portion J16, the ratchet teeth J14, and the second side edge portion J17 are continuously formed in this order at the edge portion of the opening portion J13 formed by the first member J1, it is simple. Although it is a structure, the movement between the engagement possible position (Q) and the interference avoidance position (R) of the engagement portion J3 can be performed more smoothly and reliably.

  In addition, since the first urging portion J7 that urges the engaging portion J3 in the direction to engage the engaging concave portions J14a and J14b is provided, the engaging portion J3 and the engaging concave portions J14a and J14b are engaged. It can be done accurately.

  Further, since the engaging portion J3 is a single lock pin that is attached to the front first member J1 and the second member J2 so as not to be removable, the engaging portion J3 can be simplified, and the ratchet mechanism Contributes to the reduction of the number of parts and the simplification of the structure of J as a whole.

  Further, by providing a moderation mechanism J8 that stops moderation when the second member J2 is positioned in the normal posture (O) and the forward bending posture (P), the second member J2 is bent in the normal posture (O) and the forward bending. A resistance with an appropriate click feeling can be obtained when positioned in the posture (P), and the locked state of the second member J2 in each posture (O), (P) can be further stabilized.

  In particular, the moderation mechanism J8 includes a moderation element J81 that can freely move in a through hole J18 formed in the second member J2, and a plurality of moderation elements J81 that are provided at a predetermined pitch on the first member J1 and can temporarily hold the moderation element J81. Since the second member J2 can be sandwiched between the pair of first members J1 and configured by the recesses J23 and J24, the moderator J81 is pulled out of the through hole J18 when the second member J2 is rotated. When the second member J2 is positioned in each posture (O), (P), the moderation element J81 can be reliably held in the first recess J23 or the second recess J24 of the second member J2 facing the second member J2. it can.

  Further, the ratchet mechanism J includes a second urging portion that urges the second member J2 provided with the recesses J23 and J24 and the first member J1 provided with the moderation element J81 in a direction approaching each other. Therefore, the moderation element J81 can be reliably engaged with any one of the recesses J23 and J24, and the function of the moderation mechanism J8 can be effectively improved. Moreover, shaft holes J11 and J21 are formed in the first member J1 and the second member J2, respectively, and an elastic disc spring J6 is disposed at one end of the shaft member J4 that is continuously inserted into the shaft holes J11 and J21. In this state, the first member J1 and the second member J2 are elastically biased in a direction in which the first member J1 and the second member J2 are brought into contact with or close to each other by being fastened using the nut J5, and the disc spring J6 is configured to be the second biasing portion Therefore, a disc spring J6 that plays the role of the second urging portion in association with the shaft member J4 that fastens the first member J1 and the second member J2 together is disposed. Compared with the mode in which the two urging portions are provided, this contributes to the reduction of the number of parts and the simplification of the structure.

  Further, since the ratchet mechanism J that exhibits such an effect is used to constitute the front folding device E that locks the upper backrest portion 43 between the normal posture (S) and the forward folding posture (T), it is easy to operate. Therefore, the posture of the upper backrest portion 43 can be changed as appropriate according to the use mode of the seated person, which is preferable. Specifically, the first member J1 is attached to the upper end portion of the middle backrest vertical frame pipe 421 constituting the middle backrest portion 42, and the second member is attached to the lower end portion of each upper backrest vertical frame pipe 431a constituting the upper backrest portion 43. By attaching the member J2, the relative angle change between the first member J1 and the second member J2 is reflected in the relative angle between the middle backrest portion 42 and the upper backrest portion 43, and the normal posture (S) of the upper backrest portion 43 is changed. The posture change between the forward bent posture (T) can be performed accurately and easily.

  Further, the front folding device E normally moves the upper backrest 43 independently of the operation of each part by each device such as the interlocking backward tilting device A (for example, the backward tilting operation of the seat 2 and the backrest 4 by the interlocking backward tilting device A). By making the posture changeable between the posture (S) and the forward bending posture (T), the posture changing operation (rotation) of the upper backrest portion 43 by the front folding device E and the operation of each part by each device (interlocking) The seat 2 and the backrest 4 by the backward tilting device A are prevented from interlocking with each other, and the chair X can be used for various usage modes of the seated person. In particular, in the posture in which the entire backrest 4 and the seat 3 are tilted backward by the interlocked backward tilting device A, the upper backrest portion 43 is positioned in the forward folded posture (T), so that it is possible to work in a reclining posture (FIG. 6 ( e)). In this case, since the part extending from the middle to the upper part of the backrest 4 is folded forward, the entire chest is folded forward, and the seated person is compared with the aspect in which the headrest 5 is folded forward with respect to the backrest 4. There is no burden on the cervical spine, and there is no fatigue.

  The present invention is not limited to the embodiment described in detail above.

  For example, in the above-described embodiment, the ratchet mechanism has a mode in which the second member that has taken the forward bending posture is inclined by approximately 15 degrees with respect to the second member in the normal posture. It goes without saying that the member may be set to take an angular posture other than this.

  In addition, although the aspect which locked the 2nd member with a normal attitude | position and a forward bending attitude | position was shown, not only this but the 2nd member is locked by the back bending attitude | position which made it bend back backward. Alternatively, the second member may be locked in a forward folding posture and a backward folding posture. That is, the second member is a first posture that is a predetermined initial posture with respect to the first member, and a rotation end posture that is rotated by a predetermined angle from this initial posture and further restricted in the same direction. What is necessary is just to change at least appropriately the angle attitude | position with respect to the 1st member of the 2nd member positioned in the 1st attitude | position and the 2nd attitude | position, and the angle attitude | position with respect to the 1st attitude | position should just be locked. . Furthermore, if the second member is configured to be locked at a plurality of angular postures in the process of rotating from the first posture to the second posture, it is possible to flexibly cope with various seating postures of the seated person. In this case, the engagement concave portions and the tooth portions provided in the ratchet teeth may be appropriately increased so that the second member can be locked in a plurality of angular postures that the second member can take.

  The ratchet teeth are provided on the second member, while the engaging member holding element for holding the engaging portion is provided on the first member, and the engaging portions are sequentially provided on the ratchet teeth as the posture of the second member is changed. You may comprise so that it may sequentially engage with the engagement recessed part.

  Further, the shapes of the engaging portion holding element and the opening are not limited to those shown in the above embodiment, and various changes may be made without departing from the above effects. For example, when a ratchet mechanism is configured by using one first member and one second member, the engaging portion holding element and the opening portion are each of a bottomed concave shape or a groove shape, and the engaging portion is A spherical shape that can be sequentially engaged with the engagement recesses of the ratchet teeth provided in the bottomed opening while being held by these bottomed engagement holding elements.

  In addition, in either the first member or the second member provided with the ratchet teeth, the member or part functioning as the first contact guide portion of the present invention is not provided, and the engagement recess of the ratchet teeth in the second posture is provided. The engaging portion may be positioned at the interference avoidance position by moving the engaging portion to be engaged in a direction for releasing the engagement with the engaging recess by an appropriate means (for example, a switch or manual operation). Similarly, the member or part that functions as the second contact guide portion of the present invention is not provided, and the engaging portion is operated by appropriate means (for example, a switch or a manual) when the rotation is returned from the second posture to the first posture. May be moved to the engagement recess of the ratchet tooth to position the engagement portion at the engageable position.

  Moreover, although the 1st biasing part was comprised using the coil spring, it may be comprised using another biasing member.

  Further, although the moderation mechanism is not an essential requirement of the ratchet mechanism, by providing the moderation mechanism, the member for changing the posture can be provided in the first posture and the second posture even if the engagement portion and the engagement recess are not closely engaged. Can be locked temporarily in posture. Thereby, the freedom degree of design of an engaging part and an engaging recessed part can also be raised. In addition, as a moderator which comprises a moderation mechanism, the protrusion which is provided in one of the 1st member or the 2nd member, and selectively elastically engages with the moderator holding part (for example, recessed part) formed in the other member Part may be applied. When the second member is configured to be locked at a plurality of angular postures in the process of rotating the first member from the first posture to the second posture, the moderator holding portion is provided so that the second member can be stopped at each angular posture. What is necessary is just to increase suitably.

  Moreover, you may use elastic members, such as a leaf | plate spring and a coil spring, as a 2nd biasing part instead of a disc spring.

  On the other hand, in the said embodiment, while attaching the 1st member J1 to the upper end part of the middle backrest vertical frame pipe 421 which comprises the middle backrest part 42, it attaches to the lower end part of each upper backrest vertical frame pipe 431a which comprises the upper backrest part 43. Although the aspect which attached the 2nd member J2 was shown, it is the aspect which provided the 1st member J1 and the 2nd member J2 in the lower end part of the upper end part of the middle backrest vertical frame pipe 421 or the upper backrest vertical frame pipe 431a, respectively. It does not matter. In this way, the number of parts can be reduced and the assembly process can be simplified.

  Further, when the ratchet mechanism of the present invention is applied to a chair provided with a first backrest portion positioned on the lower side and a second backrest portion positioned on the upper side, the backrest is partitioned at a predetermined height position, You may comprise the backrest apparatus for making a backrest part bend back from a normal posture back with respect to a 1st backrest part using a ratchet mechanism. Or you may comprise the backrest angle adjustment apparatus which makes the whole backrest incline forward with respect to a seat, or inclines back using the ratchet mechanism of this invention. In the latter case, a ratchet mechanism may be disposed at the joint portion between the seat and the backrest.

  The chair shown in the above embodiment is an example, and the ratchet mechanism according to the present invention may be applied to a chair having another configuration.

  Further, in various articles having not only a chair but also one member capable of changing the relative angle and other members, the ratchet mechanism of the present invention is disposed at a joint portion between the one member and the other member. The relative angle change between the one member and the other member can be easily performed.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

The whole perspective view showing the chair concerning one embodiment of the present invention. The left view which shows the chair which concerns on the same embodiment abbreviate | omits and shows typically. The front view. The disassembled perspective view of the headrest in the embodiment. The figure which shows the usage condition of the chair which concerns on the embodiment typically. The figure which shows typically the other usage condition of the chair which concerns on the same embodiment. The figure which shows the lumbar support apparatus in the embodiment. The whole perspective view of the ratchet mechanism concerning the embodiment. The figure which shows the 1st member and 2nd member in the embodiment. Action | operation explanatory drawing of the ratchet mechanism which concerns on the same embodiment. The figure which shows the predetermined end surface of the ratchet mechanism shown in FIG. Action | operation explanatory drawing of the front bending apparatus in the embodiment. The elements on larger scale of FIG.10 (b).

Explanation of symbols

4 ... backrest 42 ... first backrest (medium backrest)
421 ... 1st back frame (middle back vertical frame pipe)
43 ... Second backrest (upper backrest)
431a ... Second back frame (upper back vertical frame pipe)
E ... Pre-folding device J ... Ratchet mechanism J1 ... First member J13 ... Opening J14 ... Ratchet teeth J14a ... First engagement recess J14b ... Second engagement recess J16 ... First contact guide (first side edge) )
J17: second contact guide (second side edge)
J18 ... through hole J2 ... second member J22 ... engaging portion holding element J221 ... first holding portion J222 ... second holding portion J23, J24, J25 ... moderation element holding portion (first recess, second recess, third recess) )
J3 ... engaging portion J4 ... shaft member J5 ... nut J6 ... second urging portion (disc spring)
J7 ... First biasing part J8 ... Moderation mechanism J81 ... Moderation child X ... Chair

Claims (15)

A ratchet mechanism that locks another member pivotally attached to one member in at least a first posture and a second posture rotated by a predetermined angle from the first posture,
A ratchet tooth provided on either one of the one member or the other member and having a plurality of engaging recesses;
An engaging portion that is held on the other side and is engageable with any of the plurality of engaging recesses when the other is positioned in the first posture and the second posture;
An engagement portion holding element provided on the other side and movably held between an engageable position where the engagement portion can be sequentially engaged with the plurality of engagement recesses and an interference avoidance position where the engagement portion does not interfere with the ratchet teeth. And comprising
The engaging portion is positioned at the engageable position when the other member is rotated from the first posture to the second posture, and the other member is moved from the second posture to the first posture. A ratchet mechanism, wherein the ratchet mechanism is positioned at the interference avoidance position when the rotation is returned. The engaging portion holding element has a long hole shape and a first holding portion capable of holding the engaging portion in the engageable position, and a long hole shape extending along a direction different from the first holding portion. 2. A second holding portion capable of holding the engagement portion at the interference avoidance position, and one end portions of the first holding portion and the second holding portion being continuous with each other. Ratchet mechanism. The same direction as the rotation direction for changing the posture of the other member positioned in the second posture from the first posture to the second posture on any one of the one member or the other member provided with the ratchet teeth And a first contact portion that contacts the engagement portion positioned at the engageable position with the rotation of the engagement portion and guides the engagement portion to the interference avoidance position using the engagement portion holding element. The ratchet mechanism according to claim 1 or 2, wherein one contact guide portion is provided. Either the one member provided with the ratchet teeth or the other member is positioned at the interference avoidance position in the process of rotating the other member positioned in the second posture back to the first posture. A second abutting guide portion is provided for abutting the engaging portion and guiding the engaging portion to the engageable position using the engaging portion holding element. 3. The ratchet mechanism according to 3. An opening that penetrates in the thickness direction of the member is formed in one of the one member or the other member provided with the ratchet teeth, and at least the first contact guide is provided at the edge of the opening. The ratchet mechanism according to claim 4, wherein the portion, the ratchet teeth, and the second contact guide portion are successively formed in this order. The ratchet mechanism according to claim 1, further comprising a first urging portion that urges the engaging portion in a direction in which the engaging portion is engaged with the engaging recess. The ratchet mechanism according to claim 1, 2, 3, 4, 5, or 6, wherein the engaging portion is a single lock pin that is attached to the one member and the other member so as not to be removable. The ratchet according to claim 1, 2, 3, 4, 5, 6 or 7, wherein the other member is locked at a plurality of angular postures in a process of rotating the other member from the first posture to the second posture. mechanism The ratchet mechanism according to claim 1, further comprising a moderation mechanism that stops moderation when the other member is positioned at least in the first posture and the second posture. . The moderation mechanism includes a moderation element disposed on one of the one member or the other member, and a plurality of moderation element holding portions provided on the other side at a predetermined pitch and capable of temporarily holding the moderation element. The ratchet mechanism according to claim 9, which is configured. The one member and the other member are both substantially plate-shaped, and a through-hole penetrated in the thickness direction through either the one member or the other member provided with the moderation element And the other member provided with the moderator holding portion is provided in a pair at a position where the one member can be sandwiched. The ratchet mechanism described. The ratchet mechanism according to claim 10 or 11, further comprising a second urging portion that urges the other member provided with the moderation element holding portion and the one member toward each other. A shaft hole is formed in the one member and the other member, and the nut is fastened with an elastic member disposed at least at one end of the shaft member continuously inserted through the shaft hole. The ratchet mechanism according to claim 12, wherein the ratchet mechanism is configured to elastically urge in a direction in which the other members abut or approach each other, and the elastic member functions as the second urging portion. A chair with a backrest,
The backrest includes a first backrest portion that is partitioned at a predetermined height position and located on the lower side, and a second backrest portion that is located on the upper side,
A normal posture in which the second backrest portion is substantially linear with at least the first backrest portion, and a folded posture in which the second backrest portion is folded forward from the normal posture with respect to the first backrest portion or backwardly folded backward. The folding device is configured using the ratchet mechanism according to any one of claims 1 to 13, and the second member of the ratchet mechanism is positioned in the first posture by the second device. A chair, wherein a backrest portion is positioned in the normal posture, and the second backrest portion is positioned in the folded posture by positioning the other member in the second posture. The first member is attached to an upper end portion of a first backrest frame constituting the first backrest portion, and the other member is attached to a lower end portion of a second backrest frame constituting the second backrest portion. 14. The chair according to 14.

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