JPH0534945U - Chair tilt controller - Google Patents

Abstract

(57) [Abstract] [Purpose] In automatically adjusting the spring constant of the spring means for elastically supporting the rearward tilting of the backrest to a value according to the weight of the person sitting on the chair, the spring after adjustment Prevent the constant from changing unexpectedly. [Structure] Load acting body (slider) for spring means 11
31 through the interlocking member (pinion shaft) 25
The spring constant of the spring means 11 is increased according to the weight of the person sitting on the chair 1 by moving the spring means 11 according to the weight of the person sitting on the chair 1. A ratchet wheel 25c is formed on the interlocking member 25, and a ratchet pawl 45 for the ratchet wheel 25c is provided on the member 14 close to the interlocking member 25. The ratchet pawl 45 meshes with the ratchet wheel 25c when the seat body 4 moves downward, and the rack pawl 45 and the ratchet wheel 25c disengage when the seat body 4 moves upward.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention provides a spring means for a chair in which the backrest can be tilted backwards against the elasticity of the spring means so that the tilting angle of the backrest becomes substantially constant regardless of the weight of the person sitting on the chair. The present invention relates to a tilt control device capable of automatically adjusting the spring constant of the device according to the weight of the person sitting in the chair.

[0002]

[Prior Art]

 The applicant of the present application proposed a tilt control device for a backrest as shown in FIG. 18 in the previous utility model registration application (Japanese Patent Application No. 2-322296). That is, according to this prior invention, the tilting motion body 103 to which the backrest 102 is attached is pivotally attached to the front end portion of the support mechanism 101 provided at the upper end of the leg body 100 by a pin so that the tilting motion body 103 can be tilted rearward, and the tilting motion body 103 is also tilted. A cantilever-shaped leaf spring 104 that elastically supports the rear tilting is provided so as to extend rearward, and a load from the tilting moving body 103 is applied between the tilting moving body 103 and the leaf spring 104. The seat body 106 is supported by the tilting motion body 103 via the weight sensitive spring 107, while the slider 105 for acting on the.

Further, the tilting motion body 103 is provided with a parallel link mechanism 108 that is rotated in the front-rear direction by the downward movement of the seat body 106, and the slider 105 is attached to the parallel link mechanism 108. The slider 105 is moved toward the base end portion of the leaf spring 104 in accordance with the descending amount of the seat body 106, and the spring constant of the leaf spring 104 is increased in proportion to the weight of the person sitting on the chair. By doing so, the tilting motion body 103 is tilted backward by the same angle regardless of the weight of the person sitting in the chair.

[0004]

[Problems to be solved by the device]

 However, in the invention of this prior application, when a spring constant of the leaf spring 104 increases due to a person sitting on a chair, there is no means for automatically maintaining the spring constant of the leaf spring 104, and the slider is Since 105 is in an unstable state in which it can move forward and backward, a person sitting on a chair leans against the backrest 102 and the downward load on the seat body 106 is reduced, or the person sitting on the chair. When the downward load on the seat body 106 is reduced by lightly lifting the waist while leaning against the backrest 102, the slider 105 moves back and the spring constant of the leaf spring 105 becomes smaller than an appropriate value. There was a problem that it might fluctuate to a small value.

The present invention aims to solve this problem.

[0006]

[Means for Solving the Problems]

 In order to achieve this object, the present invention pivotally attaches a tilting motion body attached to a backrest to a support mechanism provided at the upper end of a leg so that the tilting motion body can be tilted rearward, and a spring means for loading the tilting motion body to the rear tilting is provided. Is formed so that the spring constant changes with the movement of the action point of the spring means, and the load acting body of the tilting motion body with respect to the spring means or the spring means is changed to the spring of the spring means according to the downward load on the seat body. In a chair configured to be movable through an interlocking member so as to increase the constant, one of the interlocking member and an appropriate member adjacent to the interlocking member has a ratchet wheel or ratchet track, and the other member. The ratchet pawl is provided so that the ratchet pawl is engaged with the ratchet wheel or the ratchet rack by a downward load on the seat body, and the ratchet pawl is released by releasing the downward load on the seat body.

[0007]

[Action / effect]

 In this configuration, when a person sits on the chair, the spring means or the load acting on the spring means moves through the interlocking member by an amount according to the weight of the person sitting on the chair, and The spring constant increases with the weight of the person sitting in the chair. At the same time, when the weight of the person applies a downward load to the seat, the ratchet pawl meshes with the ratchet wheel or ratchet track, and the interlocking member is held immovably, so that the spring means and the spring concerned. Since the relative position of the load effector with respect to the means is kept unchanged, the spring constant of the spring means is kept at a value after being automatically adjusted by the person sitting on the chair.

Then, when a person stands up from the chair and the downward load on the seat is released, the engagement between the ratchet pawl and the ratchet wheel or ratchet track is released, and the interlocking member returns to a movable state. The spring constant of the spring means can be adjusted again. As described above, according to the present invention, when a person leans against the backrest, the spring constant of the spring means for the rearward tilting of the backrest can be maintained at a magnitude corresponding to the weight of the person sitting in the chair. Therefore, the sitting comfort of the chair can be significantly improved.

[0009]

【Example】

 Next, an embodiment of the present invention will be described with reference to the drawings. 1 to 16 show a first embodiment, and in these figures, a chair is designated by reference numeral 1 is a chair having a support mechanism 3 provided at an upper end of a leg body 2 and a seat body 4 attached to the support mechanism 3. A backrest 5 integrally connected to the seat body 4 is provided, and cushion materials 4a and 5a are stretched on the upper surface of the seat body 4 and the front surface of the backrest 5, respectively.

The seat body 4 is divided into front and rear parts, and as shown in FIG. 5, the abutting part between the front seat body 4b and the rear part 4c is formed in a zigzag shape in plan view, 4b and the rear seat body 4c can be separated from each other in a state where they overlap with each other in a side view. The support mechanism 3 is a box-shaped rotary frame having a fixed frame body 6 fixed to the upper ends of the legs 2 and having a substantially U-shaped opening in cross section, and an upward opening fitted to the fixed frame body 6 from below. A body 7 is provided, and the rear end portions of the left and right side plates 7a, 7a of the rotating frame body 7 are horizontally extended with respect to the left and right side plates 6a, 6a of the fixed frame body 6. (1) By pivotally attaching the pivoting pin 8 and further contacting the rear end portion 7b 'of the bottom plate 7b of the rotating frame body 7 with the lower surface of the fixed frame body 7, only the forward tilting is possible. ing.

A front end portion of an L-shaped tilting motion body 9 attached to the backrest 5 at a front end portion of the left and right side plates 7a, 7a of the rotary frame body 7 is attached to a pair of left and right second pivot pins 10. On the other hand, a pair of left and right cantilever-shaped load acting portions 11a extending rearward are provided on the inner surface of the front plate 7c of the rotating frame 7 as an example of spring means for the tilting motion body 9. A torsion coil spring 11 is provided. As shown in FIGS. 5 and 12, a collar 12 is fitted on the second pivot pin 10.

The tilting motion body 9 includes a base body 13 formed of a metal plate or the like, and a support body 14 made of synthetic resin or the like fixed to the upper surface of the base body 13 with screws. The downward projection 14a formed on the support 14 is fitted into the longitudinally extending recess 13a formed in the support 13, and the left and right side plates 14b and 14b formed substantially in the front and rear halfway of the support 14 are attached to the rotary frame. The second pivot pin 10 is pivotally attached to the left and right side plates 7a, 7a of the body 7.

Further, the left and right sides of the lower surface of the base body 13 are fixed with horizontal portions 15a of a pair of left and right support rods 15 formed in a substantially L shape in a side view, and the upper ends of the left and right support rods 15 are seen in a plan view. A bush with a collar formed by connecting with a U-shaped connecting rod 16 and formed on a cylindrical body 16a having upper and lower openings fixed to both left and right ends of the connecting rod 16 so as to be slightly deformed by a hard synthetic resin or the like. A body 17 is inserted and fitted into the bush body 17, and a cylindrical portion 5b integrally formed on both left and right side portions of the backrest 5 is fitted.

A first guide body 19 having a cylindrical portion 18 that opens upward and a key groove 19a that extends in the vertical direction is provided at a substantially middle portion between the rear end portion of the support body 14 of the tilting motion body 9 in the left-right direction. And the guide bush 20 are inserted into the tubular portion 18, and the guide bush 20 is provided on the rear support plate 21 made of synthetic resin or the like for supporting the rear seat 4c so as to project downward. The tube 22 is inserted and the coil tube 23 for applying a feeling of weight for lowering the seat body 4 according to the weight of the person sitting on the chair 1 is inserted into the guide tube 22.

Further, a vertically long first rack 24 having rack teeth formed on the front surface is fixed to the lower surface of the front end portion of the rear support plate 21 by screwing, and the first rack 24 is fixed to the support body 14 In the key groove 19a of the first guide body 19 in the above. Further, a pinion shaft 25 having a first pinion gear 25a meshing with the first rack 24 is rotatably attached to the left and right side plates 14b, 14b of the support body 14 of the tilting motion body 9 via a shaft body 26. On the left and right sides of the pinion shaft 25 that sandwich the first pinion gear 25a, second pinion gears 25b having a diameter larger than that of the first pinion gear 25 are formed. A claw wheel 25c having a diameter larger than that of the second pinion gear 25b is formed.

In addition, in the upper surface of the support body 14 of the tilting motion body 9, guide grooves 28a are formed on the inner side surface at two locations corresponding to the second pinion gears 25b. A second guide body 28 having a longitudinal length is fixed and a second rack 30 having rack teeth formed on the upper surface is slidably attached to the left and right second guide bodies 28, 28, respectively. A wing piece 30a protruding from the side surface of 30 is fitted in the guide groove 28a of the second guide body 28 so as to be slidable back and forth.

Further, the front ends of the left and right second racks 30, 30 are connected by a connecting pin 32, and a roller-like slider 31 is fitted on the connecting pin 32 as an example of a load acting member. 31 is configured so as to be able to contact the load acting portions 11a of the left and right torsion coil springs 11 at a portion in front of the second pivot pin 10. The slider 31 may be formed integrally with the connecting pin 32.

In this case, on the upper surface of the support body 14 of the tilting motion body 9, a stopper projection 29 with which the slider 31 abuts is formed so as to regulate the retracted position of the left and right second racks 30. In the state in which the tilting motion body 9 does not rotate, the load acting portion 11a of the torsion coil spring 11 contacts the stopper projection 29, and the load acting portion 11a of the torsion coil spring 11 and the slide element. A small gap e is formed between the gap 31 and the gap 31.

The left and right torsion coil springs 11 are fitted on a support shaft 33 which penetrates the left and right side plates 7a of the rotating frame body 7. The coil portions of the left and right torsion coil springs 11 are made of hard rubber or the like. A buffer member 34 having a semicircular cross section formed of a material that can be slightly elastically deformed is arranged so that the flat surface 34a of the buffer member 34 contacts the supporting shaft 33 in a state where the flat surface 34a is positioned obliquely downward. By making the diameter of the coil portion 11 smaller, the rearward tilting of the tilting motion body 9 is elastically supported.

The left and right torsion coil springs 11 are supported by a support piece 35 formed by cutting and raising the bottom plate 7 b of the rotating frame body 7. Further, the front plate 7 c of the rotating frame body 7 is supported. A bolt 36 is screwed into the fixed end portion 11b of the torsion coil spring 11 so as to adjust the initial elastic force of the torsion coil spring 11. Reference numeral 37 shown in FIG. 6 denotes a collar fitted to the support shaft 33 in order to prevent lateral displacement of the both torsion coil springs 11.

A front support plate 38 is fixed to a horizontal flange portion 7 d formed at the front end of the rotating frame body 7, and a front seat body 4 b is fixed to the front support plate 38. Further, an arm body 39 having a U-shaped cross-section that extends obliquely upward toward the rear is fixed to the rear end portion of the fixed frame body 6, and the upper ends of the left and right side plates 39a, 39a of the arm body 39 are fixed. A long slot 40 extending obliquely in a side view is formed in the portion, while a connecting portion 41 between the rear seat body 4c and the backrest 5 is formed to be curved backward in a side view, and the rear seat body 4c is formed. A pair of left and right brackets 42 extending substantially downward are integrally or separately formed at a connecting portion 41 between the backrest 5 and the backrest 5, and guide pins 43 inserted into the left and right brackets 42, 42 are provided in the arm body 39. The rear seat body 4c and the backrest 5 are configured to be tilted backward by being inserted into the left and right long holes 40, 40.

Reference numeral 44 shown in FIGS. 6 and 12 to 13 is a spring constant according to the present invention, which holds the spring constant of the torsion coil spring 11 at an adjusted value by a downward load on the seat body 4. The holding device is shown and is configured as follows. That is, a ratchet pawl 45 extending rearward in a side view is provided between the side plate 14b and the bracket plate 14c projecting from the supporting body 14 of the tilting motion body 9, and the ratchet pawl 45 has a left-right direction. The guide pins 46 extending to the left side of the ratchet pawl 45 are inserted, and the guide protrusions 45e that are inclined in a direction intersecting the longitudinal direction of the ratchet pawl 45 are provided on the left and right side surfaces of the ratchet pawl 45, while the side plates 14b and the bracket of the support body 14 and the bracket are provided. An elongated hole 47 into which the guide pin 46 is fitted and a guide piece 48 with which the guide protrusion 45 e abuts on the guide plate 14 c in an inclined shape along the same direction as the guide protrusion 45 e of the ratchet pawl 45. It is formed so as to extend.

Further, the side plate 14 b and the bracket plate 14 c of the support body 14 are pivotally attached to a part rearward of the ratchet pawl 45 with a pin 50 at a front and rear midway part of a lever 49 extending in the front-rear direction. A front end portion 49a of the lever 49 is formed into a bifurcated shape in a plan view so as to be fitted to the ratchet pawl 45, and the guide pin 46 is inserted into the bifurcated front end portion 49a and is passed through the guide pin 46. The hole 51 is formed as an elongated hole extending along the longitudinal direction of the ratchet pawl 45, and a compression spring 52 is inserted between the rear end portion of the lever 49 and the rear support plate 21 for the rear seat body 4c. ..

Further, a tension spring 53 is inserted between a portion of the lever 49 in front of the pivot pin 50 and the support body 14 of the tilting motion body 9 to move the ratchet pawl 45 from the ratchet wheel 25c. A leaf spring 54 is provided on the upper surface of the support 14 in the tilting motion body 9 so as to urge the ratchet pawl 45 to come in contact with the lower end of the ratchet pawl 45 when the ratchet pawl 45 retracts.

In the above configuration, when a person sits on the chair 1, the rear seat body 4c is lowered against the elasticity of the coil spring 23, and the first rack is interlocked with the lowering movement of the rear seat body 4c. Since the pinion shaft 25 rotates via 24, the left and right second racks 30 advance as shown by the alternate long and short dash line in FIG. 8 and the solid line in FIG. 14, and the support span L1 of the left and right torsion coil springs 11 is short. Therefore, the spring constants of the left and right torsion coil springs 11 increase.

At this time, since the spring constant of the coil spring 23 is constant, the descending amount of the rear seat body 4c is proportional to the weight of the person who sits on the chair 1, so that the left and right second racks 30 and 30 can be controlled. The amount of movement also increases in proportion to the weight of the person sitting on the chair 1, and as a result, the spring constants of the left and right torsion coil springs 11, 11 increase in proportion to the weight of the person sitting on the chair 1.

At the same time, when the rear seat body 4c descends, the lever 49 rotates in the direction of arrow C via the compression spring 52, and the ratchet pawl 45 advances toward the ratchet wheel 25c, so that the ratchet pawl 45 moves. The claw portion 45a abuts against the ratchet wheel 25c, and in that state, the ratchet claw 45 moves in small steps toward and away from the ratchet wheel 25c, while the pinion shaft 25 rotates in the direction of the arrow B to rotate the pinion shaft 25. When is stopped, the ratchet 45 meshes with the ratchet wheel 25c, and the pinion shaft 25 is held irreversibly. Therefore, the spring constant of the torsion coil spring 11 is held at an automatically adjusted value.

When the person sitting on the chair 1 leans against the backrest 5, the tilting motion body 9 tilts backward about the left and right second pivot pins 10 as shown by the solid line in FIG. The backrest 5 and the rear seat body 4c are tilted rearward, and the rearward tilting of the tilting motion body 9 is elastically supported by the left and right torsion coil springs 11 and 11 via the slider 31, and A locking function for tilting is added.

When a person raises his / her waist from the chair 1 and the rear seat body 4c rises, the lever 49 is returned to the original posture and rotated by the tension spring 53, so that the ratchet pawl 45 is also not engaged with the ratchet wheel 25c. Retreat to mesh. When the torsion coil spring 11 is located in front of the second pivot pin 10 that is the pivot portion of the tilting motion body 9 as in the embodiment, the slider is moved as shown in FIGS. 8 and 14. The distance (L2) between the second pivot pin 10 and the slider 31 and the distance L3 from the second pivot pin 10 to the backrest 5 (L2 : L3) becomes smaller, and the load acting on the torsion coil spring 11 becomes smaller than that when the tilting motion body 9 tilts backward without the slider 31 moving forward.

Therefore, in addition to the spring constant of the torsion coil spring 11 increasing according to the weight of the person sitting on the chair 1, the load acting on the torsion coil spring 11 is larger than that before the slider 31 is advanced. Since it becomes smaller, the torsion coil spring 11 is less likely to be deformed according to the weight of the person sitting on the chair 1, and as a result, regardless of the weight of the person sitting on the chair 1, the torsional movement of the tilting motion body 9 against the rearward tilting of the tilting motion body 9 is reduced. The amount of deformation of the coil spring 11 can be kept substantially constant, and the locking function can be further improved.

A stopper body 55 having an L-shape in a side view is formed on the lower surface of the rear end portion of the base body 13 of the tilting motion body 9, and a horizontal portion 55 a at the lower end thereof is provided on the lower surface of the rear portion of the fixed frame body 7. By abutting against each other, the forward tilt angle of the tilt motion body 7 is regulated. The stopper body 55 has a cutout hole 55b which is fitted into the leg 2 when the tilting motion body 9 is tilted backward so that the tilting motion body 9 can be tilted backward.

By the way, in the case where the rotating frame body 7 is configured to be capable of tilting forward as in the embodiment, when the tilting motion body 9 tilts backward due to the leaning of the person on the backrest 5, the tilting motion body is tilted. 9 tilts rearward about the second pivot pin 10, but the pivot frame 7 can tilt forward about the first pivot pin 8 and the tilting motion body 9 tilts backward. In this state, there is no means for elastically supporting the forward tilting of the rotating frame body 7, and therefore, when a person leans on the backrest 5, the whole body can be moved forward and backward without changing the angle between the upper body and the lower body. When it is swung, the rotary frame body 7 and the tilting motion body 9 are tilted forward about the first pivot pin 8 while keeping the tilting angle of the tilting motion body 9 with respect to the rotation frame body 7 unchanged. As a result, the elastic force of the torsion coil spring 11 does not act on the seat body 4 and the backrest 5. There is a risk of

In regard to this point, as shown in FIG. 7 and FIGS. 10 to 12, as shown by reference numeral 56, a pair of left and right tilts provided on the left and right sides provided between the tilting motion body 9 and the fixed frame body 5. This is dealt with by the guide means 56. That is, the forward / backward tilt guide means 56 includes a pair of left and right first bracket plates 58 respectively disposed at a pair of left and right first punched holes 57 formed in the bottom plate 7b of the rotating frame body 7, and The left and right first bracket plates 58, 58 are provided with a protrusion 59 projecting downward from the support 14 of the tilting motion body 9 between the left and right first bracket plates 58, 58. A guide hole 61 is formed in each of the left and right first bracket plates 58 and 58, into which the guide pin 60 fixed to the protrusion 59 is fitted.

At this time, the guide hole 61 is formed into a long hole having a substantially front-rear longitudinal direction so that the tilting motion body 9 is allowed to rotate about the second pivot pin 10. In the state where the moving body 9 is tilted rearward, the rotary frame body 7 is configured so as not to be tilted forward, and further, at the rear end of the guide hole 61, an inclined portion 61a extending obliquely rearward in a side view is continuously formed. The tilting motion body 9 and the rotating frame body 7 are formed so as to be tiltable forward around the first pin 8.

Further, at the lower part of the support mechanism 3, a means for elastically supporting the forward tilting of the rotating frame body 7 by the torsion coil spring 11, in other words, the torsion coil spring 11 is provided. A pair of left and right link bodies 62 formed in a lateral V shape in a side view are provided as means for using the spring means for the rearward tilting of the seat body 4 and the backrest 5 and the forward tilting of the seat body 4. ing.

That is, the left and right link bodies 62 are arranged at the right and left portions of the second punched hole 63 formed in the bottom plate 7b of the rotating frame body 7 as appropriate. The rear end is pivotally attached to a second bracket plate 64 protruding from the fixed frame body 6 in a substantially forward direction by means of pins 65 extending in the left-right direction, while the lower ends of the front portions of both link bodies 62 are connected to the rotary frame body 7. A pair of left and right downwardly facing pieces 66, 66 formed by cutting and raising the bottom plate 7b of the link body 62 are pivotally attached by a left and right longitudinal pin 67 with a collar 67a. In the lower surface of the base body 13 in FIG.

When the tilting motion body 9 tilts backward, the posture of the rotating frame body 7 does not change. Therefore, the tilting motion body 9 is separated from the link body 62, and the tilting motion body 9 is free to move. Can be tilted backwards. On the other hand, when the seat body 4 and the rotating frame body 9 are tilted forward, if the link body 62 is not present, the tilting motion body 9 and the rotating frame body 7 are integrally tilted forward, and the rotating frame body is tilted. The forward tilt of 7 is not elastically supported.

However, since the link body 62 is provided in the portion between the first pivot pin 8 and the coil portion of the torsion coil spring 11, as shown conceptually in FIG. When the body 9 tilts forward by a certain angle θ, the descending amount h2 of the link body 62 becomes smaller than the descending amount h1 of the torsion coil spring 11, so that the torsion coil spring 11 must move downward against its elasticity. The elastic deformation of the torsion coil spring 11 elastically supports the forward tilting of the rotary frame 7 and tilting motion body 9.

In this case, when the person sitting on the chair 1 leans forward, the force acting on the front part of the seat body 4 acts on the tilting motion body 9 when leaning against the backrest 5. Since the force is small compared to the force, if the torsion coil spring 11 simply supports the forward tilting of the rotating frame body 7, the torsion coil spring 11 is too hard and the seat body 4 is tilted forward. It gets harder.

However, in the configuration of the embodiment, since the tilting motion body 9 is also tilted forward and the torsion coil spring 11 is elastically deformed, the person sitting on the chair 1 leans forward. The seat body 4 and the tilting motion body 9 can be surely tilted forward, and therefore, with one torsion coil spring 11, the back tilting of the backrest 5 and the tilting movement of the seat body 4 can be performed. Both can be properly supported.

In this case, as described above, since the tilting motion body 9 is restricted by the stopper body 55 in the forward tilt angle within the predetermined range θ, it is rotated after the tilting motion body 9 stops tilting forward. Only the frame body 7, in other words, only the front seat body 4b, tilts forward against the elastic force of the torsion coil spring 11. In addition, in the embodiment, since the backrest 5 itself can be slightly deformed and deformed, when a person sitting on the chair 1 leans against the backrest 5, the backrest 5 is deformed so as to be tilted rearward as a whole and to be closely attached to the back of the person. In addition, since the backrest 5 is pulled downward by the guide action of the elongated hole 40 of the arm body 39, the backrest 5 is rearward at an angle smaller than the rearward inclination angle of the tilting motion body 9. Tilt.

FIG. 16 to FIG. 17 show a second embodiment, which is a ratchet extending between the side plate 14b of the support member 14 and the bracket plate 14c of the tilting motion body 9 in a rearward tilted shape in a side view. A pawl 45 is provided, and the ratchet pawl 45 is pivotally attached to a pin 79 at the upper end portion so that the pawl portion 45a at the lower end of the ratchet pawl 45 can be engaged with and disengaged from the ratchet wheel 25c. The torsion spring 80 urges the claw portion 45a away from the ratchet wheel 25c, and further, a leaf spring 81 extending rearward is fixed to the ratchet pawl 45, and the rear end of the leaf spring 81 is seated. It contacts the lower surface of the body 4.

Reference numerals 82 and 83 are stopper pieces for restricting the rotation range of the ratchet pawl 45. Also in this embodiment, when the seat body 4 is moved downward, the ratchet pawl 45 has its pawl portion 45a abutted against the ratchet wheel 25c, and in that state, the ratchet wheel 25c rotates in the direction of arrow B, When the descending movement of the seat body 4 is allowed and the rotation of the ratchet wheel 25c is stopped, the claw portion 45a of the ratchet claw 45 meshes with the ratchet wheel 25c, and the pinion shaft 25 is held irreversibly.

In both of the above embodiments, the torsion coil spring was used as the spring means. However, the spring means of the present invention can use other types of springs such as leaf springs and rod-shaped spring bodies. In addition, the spring means is movably provided on the tilting moving body, while the rotating frame body or the fixed frame body is provided with a load acting body contacting the spring means, and the position of the load acting body with respect to the spring means is provided. It is also possible to adjust the spring constant of the spring means by changing.

Further, a ratchet rack is formed on a member that reciprocates like the second rack 30, and a ratchet claw provided on the support body 14 or the like is engaged with or disengaged from this, or the ratchet rack is attached to the support body 14. Other forms of ratchet mechanism may be adopted, such as forming and engaging the ratchet pawl provided on the interlocking member such as the pinion shaft 25. Further, only the backrest may be attached to the tilting motion body.

Furthermore, the means for moving the slider when seated is not limited to the mechanism composed of the rack and the pinion as in the embodiment, but may be another mechanism such as a link mechanism.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a chair according to a first embodiment.

FIG. 2 is a sectional view taken along line II-II of FIG. 5 in an assembled state.

FIG. 3 is a schematic perspective view showing attachment of a tilting motion body.

FIG. 4 is an exploded perspective view showing an outline of a weight sensitive mechanism.

FIG. 5 is a schematic perspective view showing attachment of a seat body and a backrest.

6 is a plan sectional view taken along line VI-VI of FIG.

FIG. 7 is a bottom view taken along the line VII-VII in FIG. 1.

8 is a sectional view taken along line VIII-VIII of FIG.

9 is a sectional view taken along line IX-IX of FIG.

10 is a cross-sectional view taken along line XX of FIG.

11 is a sectional view taken along line XI-XI of FIG.

12 is a sectional view taken along line XII-XII of FIGS. 6 and 10. FIG.

13 is a sectional view taken along line XIII-XIII in FIG.

FIG. 14 is a diagram showing a rearward tilted state of a tilting motion body.

FIG. 15 is a conceptual diagram showing an operating state when the seat body is tilted forward.

FIG. 16 is a diagram showing an operating state of a spring constant holding device.

FIG. 17 is a cross-sectional view of essential parts showing a second embodiment.

FIG. 18 is a conceptual diagram showing prior art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 chair 2 leg body 3 support mechanism 4 seat body 5 backrest 6 fixed frame body 7 rotating frame body 9 tilting motion body 10 second pivot pin 11 torsion coil spring as an example of spring means 13 support body in tilting motion body 23 Coil spring for application of weight feeling 24 First rack 25 Pinion shaft 25c Claw wheel 30 Second rack 31 Slider 44 Spring constant holding device 45 Ratchet claw 45a Claw 49 Lever

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Hiroshi Iwabuchi 1-4-18 Imafukuhigashi, Joto-ku, Osaka

Claims (1)

[Scope of utility model registration request] 1. A tilting motion body to which a backrest is attached is pivotably attached to a support mechanism provided at the upper end of a leg body so as to be able to tilt rearwardly, and spring means for the rearward tilting of the tilting motion body is used to move the load application point. The spring means or the load acting body of the tilting motion body with respect to the spring means, and the interlocking member for increasing the spring constant of the spring means according to the downward load on the seat body. In a chair configured to be movable via the interlocking member and an appropriate member adjacent to the interlocking member, a ratchet wheel or ratchet rack is provided for one member, and a ratchet pawl is provided for the other member. A tilting control device for a chair, wherein ratchet pawls are engaged with the ratchet wheel or ratchet rack by a downward load on the body, and are released by releasing the downward load on the seat body.