JP4754680B2 - Tilt range adjustment device for backrest in chair - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a device in which a tiltable range of the backrest can be adjusted in a chair in which the backrest can be tilted rearward and downward against a spring.
[0002]
[Prior art]
Various chairs have been proposed in which the backrest can be tilted backwards and downwards against the spring. It was designed to be able to tilt between the maximum tilted rearward tilted position and the range of tilting of the backrest could not be adjusted, so the usability was bad.
[0003]
Therefore, the present inventors have developed a device that solves such a problem and can freely adjust the tiltable range of the backrest, and has filed a patent application (Japanese Patent Application No. 11-318834 (Heisei Heisei). Filed November 9, 2011)).
[0004]
[Problems to be solved by the invention]
However, the invention of the above-mentioned prior application converts the rotational motion of the backrest (backrest heel) into a linear motion in the front-rear direction of the tilting range adjusting member, and limits the moving range. The problem is that the means becomes complicated and the entire apparatus becomes large.
[0005]
The present invention provides a tilting range adjustment device for a backrest of a chair, which has solved such problems, that is, can be simplified in structure, reduced in size and weight, and improved so as to reduce manufacturing costs. It is aimed.
[0006]
[Means for Solving the Problems]
According to the present invention, the above problem is solved as follows.
(1) The front end portion of the dorsal fin extending forward from the lower end of the backrest is pivotally supported on a support base supporting the seat with an axis facing in the left-right direction, and the backrest is integrated with the backrest in the support base. A first restricting member for restricting a turning range in one direction of the tip of the arm and a second restricting member for restricting the turning range in the opposite direction. The first and second operation levers disposed below the seat are provided so as to be moved back and forth independently of each other, and moved to the respective regulating members in the front-rear direction . A projecting amount of the tip of the arm into the rotation trajectory gradually increases, and a generally wedge-shaped contact portion is provided so as to reduce the rotation range of the arm.
[0007]
(2) In the above item (1) , the contact portion of each regulating member is formed in a step shape, and the rotational range of the backrest is regulated stepwise.
[0008]
(3) In the above item (1) or (2) , the tip of the operating arm fixedly fitted to the rotating shaft of the first operating lever and the first restricting member are connected by a rod, and the first operating lever The first restricting member is moved in the front-rear direction by the turning operation.
[0009]
(4) In any one of the above items (1) to (3) , the tip of the operating arm that rotates in synchronization with the rotation shaft of the second operation lever and the second restricting member are connected to the first tension member. It is connected with a spring, and the second restricting member is biased between the second restricting member and the support base with a biasing force weaker than the biasing force of the first tension spring, and is opposite to the biasing direction of the first tension spring. A second tension spring is provided that biases in the direction.
[0010]
(5) In any one of the above items (4) , the rotation shaft of the second operating lever and the shaft of the operating arm are linked to each other with a pair of spur gears.
[0011]
(6) In the above item (4) or (5) , when the operating arm is rotated to one limit, it is elastically engaged with the shaft provided in the support base and held in that position. An elastic engagement piece is provided.
[0012]
(7) In any one of the above items (1) to (6) , a pair of left and right cylinder shafts are rotatably disposed in a left and right cylindrical body provided on both side walls of the support base. The outer end of each arm is fixed to the front end of a pair of left and right dorsal fins, and the base end of a pair of left and right arms facing the same direction is fixed to the inner end, and the left and right ends of both arms A first restricting member that restricts rotation of the arm in one direction by abutting one end of the shaft on one side of the arms. A second restricting member that restricts the rotation of the arm in the other direction by contacting the other end of the shaft is disposed on the other side of the arms.
[0013]
(8) above (7) have contact in the item to the left and right cylinder axis, by inserting the torsion bar facing the lateral direction, fixed respectively opposite ends thereof to the back rod of the right and left, and of right and left cylindrical shaft Between the ends, the base end portion of the adjustment plate is fixed to the center portion of the torsion bar, and the angle of the front end portion of the adjustment plate is set in the space sandwiched between the pair of left and right arms and the shaft of the front end portion. An angle adjusting means for adjusting is provided.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in FIGS. 1 and 2, a caster (2) is provided at the tip of the support leg (1) extending radially from the center, and the leg is located at the center of the support leg (1). A column (3) is erected and a support base (4) is fixed to the upper end of the leg column (3).
[0015]
The support base (4) has an L-shape in a side view, extends rearward and upward, and has a pair of left and right dorsal fins (6) that support the backrest (5). The backrest (5) and the backrest (6) are pivotally mounted so as to be pivotable about an axis that faces the direction, and the backrest (5) and the backrest (4) are provided with an elastic reclining mechanism (7) and a tilting range as will be described later. The adjusting device (8) can be tilted backward from the standing position as shown in FIG. 1 within the range defined by the tilting range adjusting device (8).
[0016]
Above the support base (4), the seat (9) moves rearward and downward via the seat support (10) in conjunction with the back tilt (5) and the back lean (6). It is supported in this way. Note that the support structure of the seat (9) and the linkage mechanism with the backrest of the seat (9) are not directly related to the present invention, so detailed description thereof will be omitted.
[0017]
On both sides of the seat receiver (10), armrests (12) are provided via supports (11) extending in the left-right direction.
[0018]
Next, details of the elastic reclining mechanism (7) and the tilting range adjusting device (8) provided in the support base (4) will be described with reference to FIG.
[0019]
The support base (4) has a box shape with an open bottom surface, and its rear portion is fitted to the upper end of the pedestal (3) and is supported on the pedestal (3) so as to be slightly inclined upward. ing.
[0020]
Tapered cylindrical bodies (13) and (14) are formed integrally on the front and rear portions of both side walls (4a) of the support base (4).
[0021]
A pair of left and right cylinder shafts (16) in the form of a hexagonal cylinder are provided in the through hole (15) penetrating each rear cylinder (14) and the side wall (4a) of the support base (4). A pair of bushes (17) and (18) are rotatably supported. The outer ends of the left and right cylinder shafts (16) projecting outward from the cylinder (14) are located on the inner end face of the lateral truncated cone-shaped receiver (19) formed at the front end of the dorsal fin (6). It is fitted into the formed hexagonal hole (20) and fixed by a set screw (21).
[0022]
The inner ends of the left and right cylinder shafts (16) are separated from each other.
In the left and right cylinder shafts (16), a series of elongated torsion bars (22) made of a stack of a plurality of leaf springs are loosely fitted, and both ends of the torsion bar (22) It is press-fitted in a rectangular hole (23) formed at the back end of the hexagonal hole (20) in the receiver (19) of 6), and is fastened by a set screw (not shown) as necessary.
[0023]
In the gap between the inner ends of the left and right cylindrical shafts (16), there is an adjustment plate (25) facing forward, in which the central portion of the torsion bar (22) is inserted into the square hole (24) formed in the base end portion. It is arranged.
[0024]
A cylindrical portion (27) in which a screw hole (26) facing substantially up and down is formed is fixed to the front end of the adjustment plate (25) facing forward.
[0025]
An adjustment screw (29) having a rotary handle (28) at the lower end is screwed into the screw hole (26), and the upper end protruding upward from the screw hole (26) is connected to the upper wall (4b) of the support base (4). ) And the torsion bar (22) when the backrest (5) is in the upright position by adjusting the distance from the upper wall (4b) to the tip of the adjustment plate (25) By adjusting the initial torsion amount, the urging force for returning the backrest (5) to the standing position can be adjusted.
[0026]
Angle adjusting means for adjusting the angular position of the adjusting plate (25) about the central axis of the torsion bar (22) is formed by the screw hole (26) and the adjusting screw (29).
[0027]
The angle adjusting means, the torsion bar (22), the cylindrical shaft (16), the cylindrical body (14), and the like form an elastic reclining mechanism (7).
[0028]
A round hole (30) and a U-shaped notch (31) are provided at a point-symmetrical position around the square hole (24) in the adjustment plate (25).
[0029]
On both sides of the base of the adjustment plate (25), there is an insertion hole (32) through which the torsion bar (22) passes in the center, and the inner end of the cylindrical shaft (16) is rotatably fitted on the outer surface. A pair of bearings (34) made of synthetic resin in which circular recesses (33) to be joined are formed, and bosses (35) projecting from the inner side surfaces thereof are connected to round holes (30 ) And a notch (31), and a projecting shaft (36) projecting on the inner surface of the opposing bearing (34) has an engagement hole (37) drilled in the center of the boss (35). Is provided so that it cannot rotate relative to the adjustment plate (25).
[0030]
On the outside of the inner end of the left and right cylindrical shafts (16) fitted in the recess (33) of the bearing (34), the base end (rear end) of a pair of left and right arms (38) facing forward The hexagonal hole (39) provided in is fitted. A shaft (40) facing in the left-right direction is provided at the tip end portion (front end portion) of both arms (38) so as to protrude to both sides.
[0031]
As shown in FIGS. 3 to 9, on the right side of both arms (38) in the support base (4), there is a first main component of the maximum back tilt angle adjusting means (41) of the backrest (5). Similarly, on the left side, the second regulating member (44) which is the main part of the angle adjusting means (43) of the standing position (initial position) of the backrest (5) is provided on the left side. (4) The upper wall (4b) and the bottom plate (46) screwed to the lower ends of a pair of front and rear bosses (45) suspended from the lower surface thereof are sandwiched from above and below, and each regulating member (42) A groove (47) formed in the upper end of (44) facing in the front-rear direction is slidably engaged with a guide protrusion (48) facing in the front-rear direction formed in the lower surface of the upper wall (4b) of the support base (4). They are arranged so as to match.
[0032]
By moving forward on the inner side surface of the first restricting member (42), the amount of protrusion of the right end portion of the shaft (40) into the vertical turning locus gradually increases, and the shaft (40) In addition, a generally wedge-shaped contact portion (49) is formed so as to make the upward rotation range of the arm (38) small.
[0033]
In this example, the lower surface of the contact portion (49) that is inclined forward and upward is stepped, and the receiving surface (50) of the shaft (40) at each step is arc-shaped close to the outer diameter of the shaft (40). is there.
[0034]
An upper portion of the first restricting member (42) is formed with a hollow hole (51) communicating with the groove (47) from the outer surface, whereby an elastic bending piece (52) is formed on the upper portion, A plurality of concave portions provided with a hemispherical protrusion (53) formed on the central upper surface thereof on one side lower surface of the upper wall (4b) of the support base (4) at the same pitch as the pitch of each receiving surface (50) By selectively engaging with (54), each receiving surface (50) is stably held at a position where it is aligned with the shaft (40).
[0035]
A rectangular step (55) is formed at the front upper corner of the outer surface of the first restricting member (42), and an engagement hole (56) facing in the left-right direction is formed at the back end. It has been drilled. An inwardly bent portion (57a) at the rear end of the rod (57) facing in the front-rear direction for linking to a first operation lever (60) described later is fitted into the engagement hole (56). Yes.
[0036]
A cylindrical shaft (58) facing left and right is rotatably supported in the left cylinder (13) at the front portion of the support base (4), and in the same direction in the cylindrical shaft (58). The core shaft (59) that faces is inserted so as to be relatively rotatable.
[0037]
The left and right ends of the cylindrical shaft (58) and the core shaft (59) projecting outward from the cylindrical body (13) have the same outer diameter in the first and second operating levers (60) and (61). The cylindrical portions (60a) and (61a) are fitted so that the cylindrical portions (60a) are in contact with each other, and the outer cylindrical portion (60a) is fixed to the core shaft (59) with a set screw (62). It is worn.
[0038]
In the first operating lever (60), the operating piece (60b) extends forward from the outer periphery of the cylindrical portion (60a), and the right end of the operating piece (60b) is connected to the second operating lever (61 ) Extends in the direction of the cylindrical portion (61a) by the same length as the cylindrical portion (61a).
[0039]
In the second operating lever (61), the operating piece (61b) extends rearward from the outer periphery of the cylindrical portion (61a), and the left end of the operating piece (61b) is connected to the first operating lever (60). ) Extends in the direction of the cylindrical portion (60a) by the same length as the cylindrical portion (60a).
[0040]
The core shaft (59) protruding from the right end of the cylindrical shaft (58) extends to the vicinity of the right side wall (4a) of the support base (4). A shaft hole (63a) drilled in the base end of (63) is fitted and fixed with a set screw (64).
[0041]
The core shaft (59) moves to the left when the left side surface of the operating arm (63) contacts the right side surface of the bifurcated piece (65) that hangs down from the lower surface of the upper wall (4b) of the support base (4). Is prevented from coming off from the cylinder (13).
[0042]
The inwardly bent portion (57b) at the front end of the rod (57) is fitted in the engaging hole (63b) formed in the distal end of the operating arm (63) and facing in the left-right direction.
[0043]
Thus, by rotating the first operating lever (60) downward, the core shaft (59) and the operating arm (63) are rotated counterclockwise in FIG. 6, and the operating arm ( 63), the rod (57) is pulled forward, and the first restricting member (42) is stepped by engaging the protrusions (53) one by one with each recess (54). The maximum back tilt angle of the backrest (5) can be limited to progressively smaller angles.
[0044]
Conversely, by rotating the first operating lever (60) upward, the first restricting member (42) is gradually moved backward by the reverse operation to the above, and the backrest (5). The maximum rearward tilt angle can be gradually increased.
[0045]
By means of the first regulating member (42), the rod (57), the operating arm (63), the core shaft (59), the first operating lever (60), etc., the maximum back tilt angle adjusting means (5) 41) is formed.
[0046]
By moving backward on the inner side surface of the second restricting member (44), the amount of protrusion of the left end portion of the shaft (40) into the vertical rotation locus gradually increases, and the shaft (40) In addition, a generally wedge-shaped abutting portion (66) is formed so as to make the downward rotation range of the arm (38) small.
[0047]
In this example, the upper surface of the abutting portion (66) that slopes backward and downward is stepped, and the receiving surface (67) of the shaft (40) in each step is arc-shaped close to the outer diameter of the shaft (40). .
[0048]
The rear upper part and the front lower part of the outer side surface (left side surface) of the second restricting member (44) have a large-diameter projecting shaft (69) having a transverse hole (68) facing in the front-rear direction and a small-diameter shaft. A projecting shaft (70) is provided to project.
[0049]
The small-diameter projecting shaft (70) has a front end of a tension coil spring (72) that is locked to a projection (71) projecting outward from the rear end outside of the left bottom plate (46). It is locked.
[0050]
In the lateral hole (68) of the large-diameter protruding shaft (69), it is formed at the rear end of the tension coil spring (73) that has a stronger biasing force than the tension coil spring (72), that is, has a large spring constant. The L-shaped locking portion (73a) thus inserted is inserted and locked.
[0051]
The front end of the tension coil spring (73) is linked to the second operation lever (61) as will be described later.
[0052]
A non-circular fitting portion (58a) formed at the left end portion of the tube shaft (58) is placed in the small diameter tube portion (61c) formed at the right end of the tube portion (61a) of the second operation lever (61). ) And the second operating lever (61) is coupled to the cylindrical shaft (58) while being prevented from rotating.
[0053]
A spur gear (74) is integrally formed at the right end of the cylindrical shaft (58), and this spur gear (74) is formed on the lower surface of the upper wall (4b) of the support base (4) immediately above. An integral sector gear (77) meshes with a shaft (76) rotatably fitted in the provided semi-cylindrical bearing recess (75) (see FIG. 8).
[0054]
An upper end portion of an operating arm (78) having a substantially semicircular arc when viewed from the side is integrally fixed to or integrally formed with the right side surfaces of the shaft (76) and the sector gear (77).
[0055]
An elastic tongue piece (79) is integrally formed in the middle portion of the operating arm (78), and the operating arm (78) is most watched about the axis (76) as shown in FIG. When rotating in the direction, the upper part of the operating arm (78) and the elastic tongue piece (79) elastically grip the portion of the core shaft (59) immediately after exiting the right end of the cylindrical shaft (58), (78) prevents it from turning counterclockwise due to paranoia from that position.
[0056]
The front end portion of the tension coil spring (73) is fixed to the pin (80) protruding rightward from the lower end portion of the operating arm (78).
[0057]
Thus, when the second operating lever (61) faces rearward and upward, as shown in FIG. 7, the operating arm (78) is held in a state in which the core shaft (59) is pressed and gripped. The restricting member (44) is located at the front limit.
[0058]
In this state, the shaft (40) and the arm (38) are in contact with the upper surface of the bottom plate (46) without being blocked by the contact portion (66) of the second restricting member (44). The backrest (5) is, for example, made to face substantially vertical, for example.
[0059]
From this state, when the second operation lever (61) is rotated rearward and downward, for example, stopped in an intermediate substantially horizontal state, the second operation lever (61), the cylinder shaft (58) and its spur gear (74) is rotated clockwise in FIG. 7, and accordingly, the operating arm (78) is rotated counterclockwise around the axis (76) together with the sector gear (77). By rotating the pin (80), the tension coil spring (73) is pushed in the loosening direction.
[0060]
At this time, when the backrest (5) is located at a substantially vertical standing position and the shaft (40) is at the position shown in FIG. 7, the rear end surface of the abutting portion (66) abuts on the front end, and The second restricting member (44) is prevented from moving backward and is held in the position shown in FIG.
[0061]
After that, when the backrest (5) is tilted backward by the seated person and the arm (38) and the shaft (40) are turned upward, the second restricting member (44) is not The two strong and weak tension coil springs (72) and (73) are moved backward to a position where the urging forces of the two springs are balanced.
[0062]
Thereafter, when the backrest (5) is raised, the shaft (40) comes into contact with, for example, the middle receiving surface (67) in the contact portion (66) of the second restricting member (44) moved rearward, It can no longer descend. Therefore, after that, the standing position (return position) of the backrest (5) is a position slightly inclined backward from the vertical state described above.
[0063]
When the second operating lever (61) is rotated to the maximum rearward and downward, the second restricting member (44) has the shaft (40) and the arm (38) turned upward by the same action as described above. After waiting to move, it moves to the rear limit as shown in FIG. 9, and at this time, the backrest (5) can return only to a position tilted considerably backward.
[0064]
When the second operating lever (61) is turned upward from a position facing downward in the rear direction to a desired position, the operating arm (78) is rotated clockwise about the axis (76) in FIG. The front end of the tension coil spring (73) is pulled forward by the pin (80).
[0065]
However, at this time, if the shaft (40) abuts one of the receiving surfaces (67) and the second restricting member (44) is pressed downward, the second restricting member (44) is immediately Does not move, waits for the backrest (5) to be tilted backward by the occupant, moves forward, and makes the standing position of the backrest (5) a desired angle.
[0066]
When the second operating lever (61) is rotated to the upper limit facing rearward and upward, the operating arm (78) elastically grips the core shaft (59) by the elastic tongue piece (79) as shown in FIG. After that, the second restricting member (44) waits for the backrest (5) to be tilted backward, then returns to the front limit, and thereafter, the standing position of the backrest (5) Will be almost vertical.
[0067]
Thus, after the backrest (5) tilts slightly backward, the second restricting member (44) moves to a position where the urging forces of the two tension coil springs (72) and (73) are balanced. Therefore, it is possible to prevent the receiving surfaces (67) of the second restricting member (44) from being worn or damaged.
[0068]
Further, by using a spur gear (74) and a sector gear (77) which is a kind of spur gear, the rotation stroke of the second operating lever (61) can be selected by appropriately selecting the gear ratio. And the amount of rotation required by the operating arm (78) can be harmonized.
[0069]
A second restricting member (44), a tension coil spring (72) (73), an operating arm (78), a sector gear (77), a cylindrical shaft (58) provided with a spur gear (74), a second operating lever (61 ) And the like, the angle adjustment means (43) for the standing position is formed, and the tilt range adjustment means (8) for the backrest (5) is formed by this and the above-mentioned maximum rearward inclination angle adjustment means (41). Yes.
[0070]
By restricting the range of movement of the shaft (40) from above and below by means of the maximum rearward tilt angle adjusting means (41) and the angle adjusting means (43) of the standing position, the backrest (5) can be changed to a desired rearward tilt angle. Can be fully restrained.
[0071]
A shaft (82) of the operating lever (81) is pivotally supported in the cylinder (13) at the right front portion of the support base (4), and this shaft (82) serves as a height adjusting means for the seat (9). Although linked, these configurations are not directly related to the present invention, and detailed description thereof will be omitted.
[0072]
As shown in FIG. 10, a pin (83) projecting from a part of the inner end surface of the cylindrical shaft (58) is provided in a vertically long direction provided immediately below the shaft (76) of the operating arm (78). Engage with the hole (84) and rotate the operating arm (78) about the axis (76) via the pin (83) and the long hole (84) as the cylinder shaft (58) rotates. Thus, the spur gear (74) and the sector gear (77) can be omitted.
[0073]
【The invention's effect】
According to the present invention, the following effects can be achieved.
According to the first aspect of the invention. Thus regulating directly by the regulating member of a pair of rotation range of the arm to rotate a Se杆integral with the arm and Se杆, with mere axial It is only necessary to connect them, and there is no need to link them by special linking means as in the invention of the prior application, the structure can be further simplified, the size and weight can be reduced, and the manufacturing cost can be reduced.
[0074]
In addition, by enabling the arm to be controlled from both directions by a pair of regulating members, the inclination angle of the standing position of the backrest (initial position) and the maximum rearward inclination angle are independent of each other. It can be set freely and is easy to use.
[0075]
Furthermore, by projecting the shaft at the tip of the arm, it is possible to always contact the contact portion of the restricting member accurately in the same state without causing a single contact or the like.
[0076]
Moreover, the rotation in one direction of the shaft is restricted by the first restricting member on one end side of the shaft, and the rotation in the other direction of the shaft is restricted by the second restricting member on the other end side of the shaft. Since it did in this way, both restriction members can be arrange | positioned with sufficient balance.
[0077]
According to the second aspect of the present invention, the range in which the backrest can be rotated is stepwise, but can be reliably adjusted, and there is no fear that the regulating member is pushed back by the load on the backrest side.
[0078]
According to the third aspect of the present invention, the connection between the first operating lever and the first restricting member can be a simple structure, and the manufacturing cost can be reduced.
[0079]
According to the fourth aspect of the present invention, when the second lever is operated in a state where a load is applied to the backrest and the second restricting member is pressed by the tip of the arm or the shaft projecting from the arm. At that time, the second restricting member does not move immediately, and when the load applied to the backrest is released, the second operating lever as described above is balanced by the balance between the first and second tension springs. It is moved to the set position by the operation of.
Therefore, the second restricting member is not forcibly moved, and wear or breakage of the second restricting member and the arm or the shaft projecting from the second restricting member and the arm can be prevented.
[0080]
According to the fifth aspect of the present invention, by appropriately selecting the gear ratio of the pair of spur gears, the rotation stroke of the second operation lever and the rotation amount required by the operating arm can be harmonized. it can.
[0081]
According to the sixth aspect of the present invention, it is possible to prevent the second restricting member from moving unnaturally due to vibration of the chair or the like, thereby eliminating the possibility of malfunction.
[0082]
According to the seventh aspect of the present invention, the right and left dorsal fins can be connected to the arms in a well-balanced manner, the left and right dorsal fins can be supported stably, and the arms and the tips thereof are projected. The shaft and the first and second restricting members can be arranged with good balance.
[0083]
According to the eighth aspect of the present invention, the first and second restricting members, the arm, the adjusting device, the torsion bar for returning the backrest to the standing position, and the adjusting means for the biasing force are provided with a narrow support. It can be arranged in a compact and well-balanced manner in the base.
[Brief description of the drawings]
FIG. 1 is a side view of a chair provided with an embodiment of the present invention.
FIG. 2 is an exploded perspective view of the same.
FIG. 3 is an exploded perspective view similarly showing the internal structure of the support base.
4 is an enlarged cross-sectional plan view taken along line IV-IV in FIG. 1. FIG.
5 is a longitudinal side view taken along line VV in FIG. 4. FIG.
6 is a longitudinal side view taken along line VI-VI in FIG. 4;
7 is a longitudinal side view taken along line VII-VII in FIG.
FIG. 8 is an enlarged vertical front view taken along line VIII-VIII in FIG.
9 is a vertical side view similar to FIG. 7, showing another operating state. FIG.
FIG. 10 is an enlarged longitudinal sectional side view of the main part showing a modification of the means for linking the cylinder shaft and the operating arm.
[Explanation of symbols]
(1) Support legs
(2) Casters
(3) pedestal
(4) Support base
(4a) Side wall
(4b) Upper wall
(5) Backrest
(6) Backpack
(7) Elastic reclining mechanism
(8) Tilt range adjustment device
(9) Seat
(10) Seat receiver
(11) Support
(12) Armrest
(13) (14) Tube
(15) Through hole
(16) Tube shaft
(17) (18) Bush
(19) Receiver
(20) Hexagon hole
(21) Set screw
(22) Torsion bar
(23) Square hole
(24) Square hole
(25) Adjustment plate
(26) Screw hole
(27) Tube part
(28) Rotation handle
(29) Adjustment screw (angle adjustment means)
(30) Round hole
(31) Notch
(32) Insertion hole
(33) Recess
(34) Bearing
(35) Boss
(36) Projection shaft
(37) Engagement hole
(38) Arm
(39) Hexagon hole
(40) axis
(41) Maximum backward tilt angle adjustment means
(42) First regulating member
(43) Standing position angle adjustment means
(44) Second regulating member
(45) Boss
(46) Bottom plate
(47) Groove
(48) Guide ridge
(49) Contact part
(50) Reception surface
(51) Meat hole
(52) Elastic flexure
(53) Protrusion
(54) Recess
(55) Step
(56) Engagement hole
(57) Rod
(57a) (57b) Inward bending part
(58) Cylinder shaft
(58a) Mating part
(59) Core shaft
(60) First control lever
(61) Second control lever
(60a) (61a) Tube
(60b) (61b) Operation piece
(61c) Small diameter cylinder
(62) Set screw
(63) Actuating arm
(63a) Shaft hole
(63b) Engagement hole
(64) Set screw
(65) Fork
(66) Contact part
(67) Reception surface
(68) Side hole
(69) Projection shaft
(70) Projection shaft
(71) Protrusion
(72) (73) Tension coil spring
(73a) Locking part
(74) Spur gear
(75) Bearing recess
(76) axis
(77) Sector gear
(78) Actuating arm
(79) Elastic tongue
(80) Pin
(81) Control lever
(82) axis
(83) Pin
(84) Long hole

Claims (8)

The front end of the dorsal fin extending forward from the lower end of the backrest is pivotally supported on a support base that supports the seat with an axis that faces in the left-right direction, and is rotated integrally with the backrest in the support base. A first restricting member for restricting a rotational range in one direction of the tip of the arm and a second restricting member for restricting a rotational range in the reverse direction. By providing the first and second operation levers disposed below and operating the first and second operation levers so as to be moved back and forth independently of each other, and by moving each of the regulating members in the front-rear direction , the tip of the arm The adjustment of the tilting range of the backrest in the chair is characterized by providing a substantially wedge-shaped contact portion that gradually increases the amount of protrusion of the portion into the turning trajectory and reduces the turning range of the arm. apparatus. The contact portion of each regulating member is a stepped, backrest backrest tilting range adjustment device in claim 1 Symbol placement of chair so as to stepwise restricting the rotation range of the. The tip of the operating arm fixedly fitted to the rotation shaft of the first operating lever and the first restricting member are connected by a rod, and the first restricting member is moved in the front-rear direction by the turning operation of the first operating lever. The tilting range adjusting device for the backrest in the chair according to claim 1 or 2 , wherein the chair is moved. The tip of the operating arm that rotates in synchronization with the rotation shaft of the second operating lever and the second restriction member are connected by a first tension spring, and between the second restriction member and the support base. And a second tension spring for biasing the second restricting member in a direction opposite to the biasing direction of the first tension spring with a biasing force weaker than the biasing force of the first tension spring. The tilting range adjustment device for the backrest in the chair according to any one of 3 above. 5. The tilting range adjustment device for a backrest in a chair according to claim 4 , wherein the pivot shaft of the second operating lever and the shaft of the operating arm are linked to each other by a pair of spur gears. The operating arm, when it is rotated until one of the limit, and elastically engaged to the shaft provided in the support base, according to claim 4 in which a resilient engagement piece which is adapted to hold in that position Or a tilting range adjusting device for the backrest of the chair according to 5 ; A pair of left and right cylinder shafts are rotatably disposed in the left and right cylinders provided on both side walls of the support base, and the outer ends of both cylinder shafts are fixed to the front ends of the left and right pair of dorsal fins. In addition, the base end portions of a pair of left and right arms facing the same direction are fixedly fitted to the inner end portion, a shaft facing the left and right direction is penetrating through the distal end portions of both arms, A first restricting member that restricts rotation of the arm in one direction is disposed by contacting the one end of the shaft, and the other end of the shaft is disposed on the other side of the both arms. The backrest tilt range adjusting device for a chair according to any one of claims 1 to 6 , wherein a second restricting member that restricts rotation of the arm in the other direction by contact is provided. Insert a torsion bar that faces in the left-right direction into the left and right tube shafts, and fix both ends to the left and right dorsal fins, and adjust the center of the torsion bar between the inner ends of the left and right tube shafts. fixing the base end portion of the plate, in the sandwiched by a pair of left and right arms and the axis of the distal portion space, according to claim 7 which is disposed an angle adjusting means for adjusting the angle of the tip portion of the adjusting plate A device for adjusting the tilting range of the backrest in the chair described.

Images