JP5386071B2 - Chair - Google Patents

Description

  The present invention relates to a chair whose seat rises in conjunction with the backward tilting of the backrest.

  As a chair with a synchro-rocking mechanism that moves the seat in conjunction with the rocking of the backrest, a chair that sinks the seat in conjunction with the backward tilt of the backrest is widely used, but conversely, it interlocks with the backward tilt of the backrest Some raise the seat.

  As a type of chair that raises the seat in conjunction with the backward tilting of the backrest, for example, there is a chair disclosed in WO00 / 74531. 49 and 50, the chair includes a leg 101, a base 102 supported by the leg 101, a back support rod 104 to which a backrest 103 is attached, and a seat support 106 to which a seat 105 is attached. And a shaft 107 for connecting the back support rod 104 to the base 102 so as to tilt backward, a link 108 for connecting the seat support 106 to the base 102, and an extension portion 112 of the back support rod 104 to the seat support 106. The shaft 109 is provided. When the backrest 103 is raised from the state shown in FIG. 49 where the backrest 103 is erected as shown in FIG. 50, the shaft 109 is raised. Further, as the shaft 109 rises, the link 108 that has fallen forward rises. For these reasons, the seat 105 rises in conjunction with the backward tilt of the backrest 103.

  In this chair, since the force that sinks the seat 105 becomes the force that erects the backrest 103, the weight of the seated person on the seat 105 generates a resistance against the backward tilt of the backrest 103. For this reason, the heavier the person, the greater the force required to tilt the backrest 103 backward, and the reaction force against the force that tilts the backrest 103 backward can be obtained according to the weight of the seated person. .

International Publication WO00 / 74531

  However, in the above-described chair, when the seat 105 is raised, the link 108 stands up from a state where the link 108 is tilted forward by rotating about the lower shaft 110. For this reason, as shown in the graph C of FIG. 39, the seat 105 is lifted most greatly at the stage where the link 108 starts to stand up, in other words, at the stage where the backrest starts to tilt backward. As shown, in the process in which the seated person tilts the backrest 103 backward, the reaction force generated at the initial stage becomes the largest, and then the reaction force decreases. In such a chair, a large force is required at the beginning of the fall of the backrest 103, and the seated person strongly leans against the backrest 103. However, since the reaction force suddenly weakens when the backrest 103 falls down to some extent, the backrest 103 tends to fall down suddenly, and the setting of the reaction force is not necessarily appropriate.

  Further, since the link 108 is used to connect the front portion of the seat support 106 and the base 102, the number of parts increases. That is, in addition to the need for the link 108, the shafts 110 and 111 provided above and below the link 108 are required, which increases the number of parts, increases the manufacturing cost, and complicates the configuration.

  An object of the present invention is to provide a chair having a simple structure and capable of maintaining a constant reaction force or an appropriate reaction force depending on the angle of the backrest when a seated person leans on the backrest.

To achieve the above object, a chair according to claim 1 is provided with respect to a leg, a base supported by the leg, a back support to which a backrest is attached, a seat support to which a seat is attached, and a base. A first swinging center shaft for connecting the back supporter so as to be able to tilt backward, and forward from the first swinging center axis and from the same height as the first swinging center axis, or the first swinging center. A second swing center shaft that is displaced above the shaft and connects the seat support to the base so as to swing vertically; a first swing center shaft and a second swing center shaft; Between the first swing center axis and the second swing center axis and displace the back support and the seat support so as to be swingable in the vertical direction. A third swing center axis that rises in conjunction with the back tilt of the back support and a second swing center axis that tilts upward and rearward in conjunction with the rise of the third swing center axis Comprising a slide mechanism for sliding mechanism is for the arc to guide which is convex to the second swing center axis linearly or lower, when the backward tilting of the backrest, from the initial rearward tilt to end increase rate of the second swing center axis is uniform, or the rate of increase Kashiga second swing center axis as the process proceeds after the backrest is gradually increased Do shall. Here, the rate of increase of the second swing center axis is h / θ, where θ is the increase in the back tilt angle of the backrest and h is the lift distance of the second swing center axis.

  Therefore, when the backrest and the back support are tilted backward about the first swing center axis, that is, when swung backward, the third swing center axis rises and the third swing center axis Since the second swing center axis moves rearward and obliquely upward in conjunction with the ascent, the seat support supported by the second swing center axis and the third swing center axis ascends as a whole. For this reason, the weight of the seated person acting in the direction in which the seat support is lowered causes a reaction force against the backward inclination of the backrest. At this time, since the second swing center axis is guided and moved rearward and obliquely upward by the slide mechanism, it does not move so as to increase greatly at the beginning of the rearward inclination and then increase slightly. The increase in the speed does not increase sharply in the initial stage of the backward tilting of the backrest. Therefore, it is possible to prevent a large reaction force from being suddenly generated in the initial stage of the backward tilting of the backrest, and thereafter the reaction force from becoming small.

Further, when causing tilted backward to lean back, from an initial rearward tilting increasing rate of the second swing center axis is made uniform up to the end, or the backrest after Kashiga the second swing center axis As the process proceeds because the increase rate is gradually increased, when for rearward inclination of the backrest, elevated seat like graph a in FIG. 39 is made uniform, or increase of the seat as in the graph B of FIG. 39 is gradually increased. Therefore, the generation of reaction force is made uniform as shown in graph A of FIG. 40, or the reaction force generated as shown in graph B of FIG. 40 gradually increases.

Furthermore, the chair according to claim 2 includes a lock mechanism for locking the back support to the base. Therefore, the back tilt of the back support is prohibited by operating the lock mechanism, and the back support can be tilted by releasing the operation of the lock mechanism.

According to a third aspect of the present invention, the lock mechanism includes a rocking body that locks the back support, a link that rocks the rocking body, and an operation unit that displaces the link. When the operating means is operated in a state where the swing of the moving body is restricted, the displacement that attempts to swing the swinging body by elastic deformation is absorbed to accumulate the force, and the swinging body can swing Then, there is provided an elastically deforming portion that exerts a force for swinging the swinging body.

  Therefore, by the operation of the operating means, the link swings the swinging body to lock or release the back support. That is, the locking mechanism is operated to prevent the back support from being tilted backward, or the locking mechanism is released to allow the back support to tilt backward. When the back support is tilted backward, the swinging of the swinging body is restricted by the back support. When the operating means is operated in this state, the elastic deformation part provided on the link absorbs the displacement that elastically deforms and causes the rocking body to rock, accumulates force, and forcibly rocks the rocking body. There is no. Then, when the back support body tilted rearward is raised, the swinging body can swing, so that the elastically deforming elastically deformed portion returns to its original shape and swings the swinging body.

  Since the chair according to claim 1 is configured as described above, when the backrest is tilted backward, it is possible to prevent a movement in which the seat is greatly raised at the beginning of the tilting and then the rise is reduced. it can. For this reason, it is possible to prevent the reaction force from suddenly weakening and falling easily after the backrest has fallen to some extent, and the comfort of the chair can be improved. In addition, the third rocking center axis is guided by the slide mechanism, the chair structure can be simplified, and an increase in manufacturing cost can be suppressed.

In the chair according to claim 1 , the slide mechanism guides the second swing central axis linearly or in an arc that protrudes downward , and when the backrest is tilted backward, The rate of increase of the second oscillation center axis is made uniform from the end to the end, or the rate of increase of the second oscillation center axis gradually increases as the back inclination of the backrest advances, so the backrest is inclined backward. At this time, ascending of the seat can be made uniform as shown in graph A of FIG. 39, or ascending of the seat can be gradually increased as shown in graph B of FIG. Therefore, almost uniform reaction force can be obtained regardless of the back tilt angle of the backrest as shown in graph A of FIG. 40, or gradually as the back tilt angle of the backrest increases as shown in graph B of FIG. The reaction force can be increased. For this reason, when the seated person leans on the backrest and tilts the backrest backward, a constant reaction force or an appropriate reaction force according to the angle of the backrest can be maintained, and the sitting comfort of the chair is further enhanced. Can be improved.

Furthermore, since the chair according to claim 2 is provided with a lock mechanism for locking the back support with respect to the base, the backrest can be fixed at a predetermined or predetermined rearward tilt angle. For this reason, the usability of the chair can be further improved.

Further, in the chair according to claim 3 , since the elastic deformation part for absorbing the relative displacement between them and storing it as a force is provided between the operating means and the rocking body, the rocking of the rocking body is limited. In this case, the rocking body is not forcibly swung, and damage to the constituent members can be prevented. Further, the operating means can be operated even when the swinging body cannot swing. If the operating means is operated in a state where the oscillating body cannot be oscillated, the oscillating body is automatically oscillated when the oscillating body can be oscillated. Therefore, the operation means can be operated without worrying about whether the back support is tilted backward. For these reasons, the usability of the chair can be further improved.

  Hereinafter, the configuration of the present invention will be described in detail based on the best mode shown in the drawings.

  1 to 6 show a first embodiment of the chair of the present invention. The chair includes a leg 1, a base 2 supported by the leg 1, a back support 4 to which a backrest 3 is attached, a seat support 6 to which a seat 5 is attached, and a back support to the base 2. 4, a first swinging central shaft 7 that can be tilted backward, a second swinging central shaft 8 that can swing the seat support 6 in the vertical direction with respect to the base 2, and a back support. 4 and the seat support 6 are swingably connected in the vertical direction, and a third swing center shaft 9 that rises in conjunction with the backward tilt of the back support 4 and a third swing center shaft 9 A slide mechanism 10 is provided that guides the second swing central shaft 8 obliquely upward and rearward in conjunction with the ascent.

  The base 2 is fitted into the upper part of the leg 1. The bottom plate 2a of the base 2 is provided with a cylindrical portion 2b that gradually decreases in diameter from the bottom to the top. The leg 1 has a built-in gas spring 18 for height adjustment. The upper portion of the gas spring 18 protrudes from the upper end of the leg 1. The upper peripheral surface of the gas spring 18 is an inclined surface that gradually decreases in diameter from the bottom to the top. Therefore, the base 2 can be attached to the upper portion of the leg 1 by inserting the upper portion of the gas spring 18 into the cylindrical portion 2b from below. At the rear of the left and right side plates 2c, 2d of the base 2, a hole through which the first swing central shaft 7 is passed, and a hole through which the second swing central shaft 8 is passed are provided at the front. In the present embodiment, the hole through which the second swing center shaft 8 is passed is a long hole, and the slide mechanism 10 is formed. In addition, this long hole is described as the long hole 10 below.

  The seat support 6 supports the seat 5 and is swingably and slidably attached to the base 2. The seat support 6 is composed of, for example, an upper plate 6a disposed above the base 2 and a pair of left and right side plates 6b and 6c depending from both side edges of the upper plate 6a, and these are formed by bending one plate material. Is formed. A seat 5 is attached to the upper plate 6a by screws, for example. The left and right side plates 6b and 6c are arranged outside the side plates 2c and 2d of the base 2. A hole through which the third rocking central shaft 9 is passed is provided at the center of the left and right side plates 6b, 6c of the seat support 6, and a hole through which the second rocking central shaft 8 is passed at the front. .

  The back support 4 supports the backrest 3 and is swingably attached to the base 2. The back support 4 is provided between, for example, a pair of left and right side plates 4a, 4b disposed between the side plates 2c, 2d of the base 2 and the side plates 6b, 6c of the seat support 6, and the left and right side plates 4a, 4b. Support plate 4c. The front and rear portions of the support plate 4c are formed in a stepped manner, the front portion being high and the rear portion being low. The rear part of the support plate 4c is placed on a receiver 4d provided at the rear part of the left and right side plates 4a, 4b, and is fixed by welding, for example. Thereby, the left and right side plates 4a and 4b and the support plate 4c are integrated. A mounting plate 11 fixed to the backrest 3 by, for example, welding is fixed to the rear portion of the support plate 4c by, for example, a bolt. The front part of the support plate 4 c extends to a position higher than the rear part, and is disposed above the base 2. A hole through which the first rocking center shaft 7 is passed is provided at the center of the left and right side plates 4a, 4b of the back support 4, and a hole through which the third rocking center shaft 9 is passed at the front. .

  The first swing center shaft 7 is passed through a hole provided in the base 2 and a hole provided in the back support 4 to connect the back support 4 to the base 2 so as to be tilted backward. A stopper 12 is fitted to the tip of the first swing center shaft 7. The second swing center shaft 8 is passed through a long hole 10 provided in the base 2 and a hole provided in the seat support 6, and the seat support 6 is connected to the base 2 so as to be swingable in the vertical direction. To do. A stopper 12 is fitted to the tip of the second swing center shaft 8. The third swing center shaft 9 is passed through a hole provided in the seat support 6 and a hole provided in the back support 4 to connect the seat support 6 and the back support 4 so as to be swingable. A stopper 12 is fitted to the tip of the third swing center shaft 9.

  The long hole 10 is, for example, a long hole that extends linearly upward and obliquely upward. A bush 13 made of, for example, polyacetal is fitted into the periphery of the long hole 10 so that the second rocking center shaft 8 can be smoothly slid. Yes. The angle of the long hole 10 is preferably inclined, for example, about 40 degrees to about 70 degrees obliquely upward and rearward, and most preferably inclined about 55 degrees obliquely upward and backward. Further, the length of the long hole 10 is, for example, 25 mm when tilted 55 degrees obliquely upward and rearward, and the second swinging central axis 8 is raised by, for example, about 20 mm.

  The second swing center shaft 8 is disposed in front of the first swing center shaft 7 and above the first swing center shaft 7. The second swing center shaft 8 is guided and displaced by the long hole 10 as the third swing center shaft 9 is displaced. The region of the displacement is in front of the first swing center shaft 7 and above the first swing center shaft 7. However, the second swing center shaft 8 is disposed in front of the first swing center shaft 7 and at the same height as the first swing center shaft 7, and is guided to the long hole 10 from this position. You may make it displace back diagonally upward. Even in this case, the second swing center shaft 8 is displaced forward of the first swing center shaft 7. The third swing center shaft 9 is between the first swing center shaft 7 and the second swing center shaft 8 and is between the first swing center shaft 7 and the second swing center. It is arranged above the line L connecting the shaft 8. The third rocking central shaft 9 is displaced as the back support 4 is tilted backward. The region of the displacement is between the first oscillation center axis 7 and the second oscillation center axis 8 and is a line connecting the first oscillation center axis 7 and the second oscillation center axis 8. Above L.

  Since the second swing center shaft 8 is not displaced in a region below the first swing center shaft 7, the second swing center shaft 8 is moved as the back support 4 tilts backward. It can be raised smoothly. Now, consider the case where the second swing center shaft 8 is disposed below the first swing center shaft 7. In this case, the third rocking center shaft 9 is above the line L connecting the first rocking center axis 7 and the second rocking center axis 8, and from the first rocking center axis 7. When the back support 4 is tilted downward, the third swing center shaft 9 swings forward and obliquely upward with the first swing center shaft 7 as the center. For this reason, a force that moves forward acts on the second swing center shaft 8, and the second swing center shaft 8 cannot be slid rearward and upward. The above-mentioned situation can be avoided by setting the displacement region of the second swing center shaft 8 above the first swing center shaft 7 or above the same height as the first swing center shaft 7. As the back support 4 is tilted backward, the second swinging central shaft 8 can be raised smoothly.

  A reaction force mechanism 14 is provided between the base 2 and the back support 4. The reaction force mechanism 14 urges the back support body 4 upward to push the back support body 4 back when the back support body 4 tilts backward, and returns it to its original position, for example, as shown in FIG. Further, the coil spring 15 and spring seats 16 provided at both ends of the coil spring 15 are used. The upper spring seat 16 slides on the peripheral surface of the shaft 17 fitted in the lower spring seat 16 and changes the distance between the lower spring seat 16 following the expansion and contraction of the coil spring 15. The lower spring seat 16 is provided with a concave portion 16a, and the upper spring seat 16 is provided with a convex portion 16b. The reaction force mechanism 14 fits the concave portion 16 a into the convex portion 2 g provided on the base 2 and inserts the convex portion 16 b into the concave portion 4 g provided on the back support body 4, whereby the base 2 and the back support body 4 are inserted. Between. The reaction force mechanism 14 is disposed behind the first swing center shaft 7, and when the back support 4 tilts backward, the coil spring 15 is compressed to generate a reaction force.

  In addition, since a well-known thing is used as the gas spring 18 for height adjustment, description is abbreviate | omitted here. The gas spring 18 is operated by a height adjusting mechanism 19. The height adjustment mechanism 19 of the present embodiment is configured by, for example, an operation lever 20 and a fixture 21 that attaches the operation lever 20 to the base 2 so as to be swingable. The operation lever 20 is a lever bent in a crank shape, extends in the width direction of the chair, and includes an extension portion 20a to which the operation plate 22 is attached, a shaft support portion 20b extending rearward from the extension portion 20a, and a shaft support portion 20b. It is comprised from the operation part 20c extended in the width direction of a chair from the front-end | tip. The shaft support portion 20b and the operation portion 20c are accommodated in the base 2, and the extending portion 20a is projected to the outside of the base 2 from a long hole 2h provided in the right side plate 2c of the base 2. The shaft support portion 20b is rotatably supported by two ribs 2i, 2i provided on the base 2 and a fixture 21 attached to the rib 2j provided between the ribs 2i, 2i. That is, the bearing is configured by sandwiching the shaft support portion 20b from above and below by the recess of the two ribs 2i and the recess of the fixture 21. The operation part 20c can be operated by pushing in the convex part 18a of the gas spring 18. The long hole 2h of the base 2 has a shape that allows the operation lever 20 to swing. As indicated by a solid line in FIG. 5, the operation lever 20 lowers the extension portion 20a by its own weight and lifts the operation portion 20c.

  When the seated person leans on the backrest 3, the backrest 3 and the back support 4 tilt backward about the first swing central shaft 7 while pressing and contracting the coil spring 15 of the reaction force mechanism 14. Thereby, the 3rd rocking | swiveling center axis | shaft 9 raises. Further, in conjunction with the rise of the third swing center shaft 9, the second swing center shaft 8 is guided by the elongated hole 10 and moves rearward and obliquely upward. That is, since the second swing center shaft 8 and the third swing center shaft 9 are lifted, the seat support 6 and the seat 5 are lifted. Since there is a seated person now, the weight of this person becomes a force for suppressing the rise of the seat 5 and a reaction force against the force for tilting the backrest 3 backward.

  Here, a chair with a reaction force set as shown in graph A or graph B in FIG. 40, that is, a chair that can obtain almost uniform reaction force regardless of the back tilt angle of the backrest 3, or the back tilt angle of the backrest 3. In a chair where the reaction force gradually increases as the size of the seat increases, the seat 3 does not easily fall over while the seat crawls on the back 3 while it is falling down. Can be improved. Therefore, it is preferable to set the reaction force as in graph A or graph B in FIG.

  In the chair of the present embodiment, the slide mechanism 10 linearly guides the second swing center shaft 8 obliquely upward and rearward. Further, the third swing center shaft 9 is displaced obliquely upward and rearward on the circumference around the first swing center shaft 7. For these reasons, the relationship between the increase in the back tilt angle (θ) of the backrest 3 and the rising distance (h) of the second swinging central shaft 8 is constant, and the backrest 3 is tilted backward when the backrest 3 is tilted backward. The rate of increase (h / θ) of the second oscillation center shaft 8 is made uniform from the initial stage to the final stage. That is, the positional relationship between the first, second, and third swing center shafts 7, 8, 9 and the inclination angle of the long hole 10 are the same as the second swing center shaft when the back support 4 is tilted backward. The increase rate (h / θ) of 8 is made uniform. Therefore, as the inclination angle of the back support 4 increases as shown in the graph A of FIG. 39, the seat support 6 or the seat 5 rises by a certain distance, and the reaction force generated as shown in the graph A of FIG. Becomes constant. For this reason, when the seated person tilts the backrest 3 backward, the reaction force does not change greatly on the way, and the backrest 3 can be continued to be tilted with almost the same force. That is, in the chair shown in FIG. 49, the reaction force suddenly weakens after the backrest has fallen to some extent, and the chair of the present invention can easily fall down. it can.

  In the present embodiment, the back support 4 is tilted backward by setting the positional relationship between the first, second, and third swinging central shafts 7, 8, 9 and the inclination angle of the long hole 10 as follows, for example. In this case, the rate of increase (h / θ) of the second oscillation center shaft 8 is made uniform. That is, in a state where the back support 4 is not tilted backward, the third swing center shaft 9 is located at a position approximately 40 degrees diagonally above and forward of the first swing center shaft 7 when viewed from the width direction of the chair. The second swing center shaft 8 is disposed at a position of approximately 7 degrees diagonally upward and forward. Further, as viewed from the width direction of the chair, the third swing center shaft 9 is disposed at a position of about 10 degrees obliquely above and below the second swing center shaft 8. Further, when viewed from the width direction of the chair, the long hole 10 is inclined approximately 55 degrees obliquely upward and backward. When the back support 4 is tilted backward from this state, the third swing center shaft 9 is displaced to a position of about 60 degrees obliquely upward and forward of the first swing center shaft 7, and the second swing center shaft 9 8 is displaced to a position of about 15 degrees obliquely above and forward of the first oscillation center shaft 7. However, the positional relationship between the first, second, and third rocking central shafts 7, 8, and 9 and the inclination angle of the long hole 10 are not limited to those described above, and the back support 4 is inclined backward. In this case, there is no particular limitation as long as the rate of increase (h / θ) of the second oscillation center shaft 8 can be made uniform.

  On the other hand, when the seated person stops leaning on the backrest 3 and raises the upper body, the coil spring 15 of the reaction force mechanism 14 extends and the back support 4 is raised forward.

  This chair has a configuration in which the third rocking central shaft 9 is guided by the long hole 10, the configuration of the chair can be simplified, and an increase in manufacturing cost can be suppressed.

  Next, the height adjustment of the seat 5 will be described. In a state where the operation lever 20 is not operated by the seated person, as shown by a solid line in FIG. 5, the operation lever 20 lowers the extension portion 20a by its own weight and lifts the operation portion 20c. For this reason, since the convex part 18a of the gas spring 18 is not operated and the length thereof cannot be changed, the length of the leg 1 is kept constant and the height of the seat 5 is kept constant.

  When the seated person lifts the operation plate 22 of the operation lever 20, the operation lever 20 swings around the shaft support portion 20b, and the operation portion 20c is lowered to project the gas spring 18 as shown by a two-dot chain line in FIG. Push in part 18a. For this reason, the length of the gas spring 18 can be adjusted, and the height of the seat 5 can be adjusted by changing the length of the leg 1. When the seated person releases the operation lever 20, the operation lever 20 returns to an unoperated state by its own weight.

  Next, a second embodiment of the chair of the present invention will be described. In addition, in this specification and drawing, the same code | symbol is attached | subjected to the same member and those duplicate description is abbreviate | omitted. The chair of this embodiment is shown in FIGS. This chair has a lock mechanism 23 for locking the back support 4 to the base 2. The lock mechanism 23 changes the inclination angle at which the back support 4 is fixed in a plurality of stages. The lock mechanism 23 is provided in the plurality of holes 24 provided in the back support 4 and the base 2, and the rear of the back support 4. It has a convex portion 25a that can enter the hole 24 when it faces the hole 24 by tilting.

  In the present embodiment, the left side plate 4b of the back support 4 is extended forward from the right side plate 4a, and a hole 24 is provided in the extended portion. For example, three holes 24 are provided at equal intervals on the same circumference centered on the first oscillation center shaft 7. However, the number of holes 24 is not limited to three.

  The convex portion 25a is, for example, a tip portion of the shaft 25. The shaft 25 is operated by a knock mechanism 26. The knock mechanism 26 is operated by a cylindrical casing 27, a first inner cylinder 28 that is operated by a seated person and reciprocates in the axial direction of the casing 27, and a first inner cylinder 28. A second inner cylinder 29 that reciprocates in the axial direction and rotates around the axis, and a first return spring 30 provided between the first inner cylinder 28 and the second inner cylinder 29, , A second return spring 31 provided between the second inner cylinder 29 and the flange 25b of the shaft 25, and a third return spring 31 provided between the flange 25b of the shaft 25 and the shaft portion 2k of the base 2. The return spring 32 is configured.

  The casing 27 is attached so as to cover a shaft portion 2k provided on, for example, the side plate 2c of the base 2. As shown in FIG. 41, the shaft portion 2k is provided with a groove 2q in a direction crossing the axis of the shaft portion 2k, and the casing 27 is provided with holes 27e and 27e in a direction crossing the axis of the casing 27. The casing 27 is prevented from being removed from the shaft portion 2k by passing the pin 33 from the hole 27e into the groove 2q. Here, the bottom surface of the groove 2q includes two inclined surfaces 2r and 2s, and the casing 27 can be rotated with respect to the shaft portion 2k from the state shown in FIG. 41A to the state shown in FIG. On the inner peripheral surface of the casing 27, a step portion 27a and a plurality of partition convex portions 27b extending in the axial direction from the step portion 27a are formed. Each partition convex part 27b is arrange | positioned at equal intervals in the circumferential direction.

  As shown in detail in FIGS. 14 to 21, a plurality of convex portions 28 a having inclined surfaces 28 b are formed in the circumferential direction on the outer peripheral surface of the inner end of the first inner cylinder 28. Each convex portion 28a is combined in two and disposed between the partition convex portions 27b and 27b. Further, on the outer peripheral surface of the center portion of the second inner cylinder 29, convex portions 29a having two inclined surfaces 29b are formed side by side in the circumferential direction. Each convex portion 29a is disposed between the partition convex portions 27b and 27b one by one. The portion of the second inner cylinder 29 outside the convex portion 29a is inserted into the first inner cylinder 28, and in the state where the convex portion 25a does not protrude from the base 2, the slope 28b and the convex portion 29a of the convex portion 28a. The slope 29b is superimposed.

  Next, the operation of the shaft 25 by the knock mechanism 26 will be described. As shown in FIG. 8, in a state where the convex portion 25a does not protrude from the base 2, as shown in FIG. 14, the convex portion 29a of the second inner cylinder 29 is located between the partition convex portions 27b and 27b. In this state, the shaft 25 is pushed back by the third return spring 32, the second inner cylinder 29 is pushed by the second return spring 31, and the first inner cylinder 28 is pushed back by the first return spring 30. It is.

  When the seated person pushes in the first inner cylinder 28 from this state, the first return spring 30 pushes the second inner cylinder 29 inward, and the second return spring 31 pushes and contracts the third return spring 32. While pushing the shaft 25. Accordingly, the convex portion 25 a protrudes from the left side surface of the base 2 and enters the hole 24 provided in the back support 4, and the back support 4 is locked to the base 2. When the first inner cylinder 28 and the second inner cylinder 29 are pushed in, as shown in FIG. 15, the convex portion 28a of the first inner cylinder 28 and the convex portion 29a of the second inner cylinder 29 are separated by a partition convex portion 27b. Move along. And if the convex part 29a of the 2nd inner cylinder 29 remove | deviates from the partition convex part 27b, as shown in FIG. 16, the slope 29b of the convex part 29a will slide with respect to the slope 28b of the convex part 28a, and the 2nd inner cylinder 29 rotates.

  Thereafter, when the seated person releases his hand from the first inner cylinder 28, the third return spring 32 moves the shaft 25, the second return spring 31 moves the second inner cylinder 29, and the first return spring 30 moves. The first inner cylinders 28 are pushed back outward. At this time, as shown in FIG. 17, the first inner cylinder 28 is pushed back to its original position, that is, until it hits the stepped portion 27a, but the second outer cylinder is halfway because the convex portion 29a is caught by the partitioning convex portion 27b. Stop at the position. For this reason, the shaft 25 does not return to the original position, and is maintained in a state where the convex portion 25 a is allowed to enter the hole 24. That is, the locked state of the back support 4 and the base 2 is maintained, and the backrest 3 is fixed at the current angle.

  Next, when a seated person pushes in the 1st inner cylinder 28, as shown in FIG. 18, the convex part 28a will move along the partition convex part 27b, and will remove the convex part 29a from the partition convex part 27b. Thereby, as shown in FIG. 19, the slope 29b of the convex part 29a slides with respect to the slope 28b of the convex part 28a, and the 2nd inner cylinder 29 rotates.

  When the seated person releases his hand from the first inner cylinder 28, the third return spring 32 moves the shaft 25, the second return spring 31 moves the second inner cylinder 29, and the first return spring 30 moves the first return spring 30. Since the first inner cylinder 28 is pushed back toward the outside, the second inner cylinder 29 rotates while sliding the slope 29b of the convex portion 29a against the end of the partition convex portion 27b. As a result, the projection 29a moves between the partition projections 27b as shown in FIG. 20, so that the second inner cylinder 29 is moved to the original position together with the first inner cylinder 28 as shown in FIG. Return. Therefore, the shaft 25 also returns to the original position, and the convex portion 25a at the tip thereof is pulled out from the hole 24, and the engagement between the back support 4 and the base 2 is released. Thereby, the angle of the back support body 4 can be changed. The back support 4 can be locked to the base 2 at a different angle by repeating the same operation and causing the convex portion 25 a of the shaft 25 to enter the other hole 24.

  The casing 27 is also a component of the height adjusting mechanism 19 that operates the gas spring 18 for height adjustment. That is, the height adjusting mechanism 19 of the present embodiment includes a casing 27, a swing shaft 34 operated by the casing 27, and an operation member 35 attached to the swing shaft 34. The swing shaft 34 is a shaft bent in a crank shape, and is swingably attached to the base 2, and the tip thereof is inserted into a long hole 27 d provided in the arm 27 c of the casing 27. As shown in FIG. 11, the swing shaft 34 is provided with a convex portion 34 a, and the operation member 35 cannot be rotated relative to the swing shaft 34 by fitting the convex portion 34 a into the concave portion 35 a of the operation member 35. It has become. Therefore, when the casing 27 is rotated around the shaft portion 2k from the state shown in FIG. 41A to the state shown in FIG. 41B, the arm 27c swings the swing shaft 34 and moves the operation member 35 in the vertical direction. It can be swung. An operation plate 36 is integrally formed at the tip of the casing 27.

  A seat mounting bracket 37 is fixed to the upper surface of the seat support 6 by, for example, welding. The seat mounting bracket 37 is provided at, for example, two front and rear locations. The seat 5 is attached to the seat support 6 by, for example, screwing the seat shell 38 to the seat mounting bracket 37. In addition, an elbow mounting bracket 39 used for mounting an armrest is fixed to the upper surface of the seat support 6 by, for example, welding. In addition, even if it is a case where the elbow mounting bracket 39 is provided like the chair of this embodiment, it is not necessary to attach an armrest.

  In the chair of this embodiment as well as the chair of FIG. 1, when the seated person tilts the backrest 3 backward, the reaction force does not change greatly on the way, and the backrest 3 can be continued to be tilted with almost the same force. , Can improve the comfort of the chair. Further, the third swinging center shaft 9 is guided by the long hole 10 that is a slide mechanism, so that the structure of the chair can be simplified and the increase in manufacturing cost can be suppressed. It is.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention.

  For example, in the above description, the slide mechanism 10 linearly guides the second rocking central shaft 8, but it does not necessarily have to guide linearly. For example, as shown in FIG. 22, it may be guided in an arc that is convex downward. That is, the long hole 10 of the base 2 may be formed in an arc shape that protrudes downward. In this case, the rate of increase (h / θ) of the second rocking central shaft 8 gradually increases as the backrest 3 advances backward. Therefore, as shown in the graph B of FIG. 39, the seat 5 rises gradually as the back tilt angle increases, so the reaction force generated as shown in the graph B of FIG. 40 is gradually increased. Can do. Also in this case, there is a sense of security when the seated person leans back on the backrest 3 and tilts backward, and the sitting comfort can be improved. In this case, the positional relationship between the first, second, and third swing center shafts 7, 8, 9 and the shape and curvature of the long hole 10 are the same as the second swing when the back support 4 is tilted backward. There is no particular limitation as long as the rate of increase (h / θ) of the central axis 8 can be gradually increased.

  In the above description, the strength of the reaction force generated by the reaction force mechanism 14 cannot be adjusted, but may be adjustable. For example, as shown in FIG. 23 or FIG. 24, an adjustment screw 40 is provided on the bottom plate 2a of the base 2, and the preload of the coil spring 15 of the reaction force mechanism 14 is adjusted by changing the protruding amount of the tip of the adjustment screw 40. You may make it adjust the strength of the reaction force to generate | occur | produce. At this time, as shown in FIG. 23, an adjustment screw 40 may be provided on the grip 41, and the amount of protrusion of the adjustment screw 40, that is, the strength of the reaction force may be adjusted steplessly by rotating the grip 41. Further, as shown in FIG. 24, an adjustment screw 40 is provided at the base end portion of the lever 42, and the protruding amount of the adjustment screw 40, that is, the strength of the reaction force is adjusted in, for example, three stages by the swinging operation of the lever 42. May be. A plate 43 having a screw hole 43a is fixed to the bottom plate 2a of the base 2 by, for example, welding. The adjusting screw 40 is screwed into the screw hole 43a and protrudes from the hole 2m of the bottom plate 2a toward the lower spring seat 16 of the reaction force mechanism 14.

  Moreover, you may comprise the locking mechanism 23 as shown, for example in FIGS. The lock mechanism 23 includes a rocking body 45 that locks the back support 4, a link 46 that rocks the rocking body 45, and an operation unit 44 that displaces the link 46. The operating means 44 gives the link 46 a displacement by which the link 46 swings the swinging body 45, and is, for example, a rotating body (hereinafter referred to as a rotating body 44). However, the operation means is not limited to the rotating body 44, and a lever (not shown) that displaces the link 46 back and forth may be used. In the present embodiment, an operation plate 47 for operating the rotating body 44 is provided.

  The rotating body 44 is disposed between the left side plate 2d of the base 2 and the wall 2n, and is fitted to the shaft 48 so as not to be relatively rotatable. A spring 49 is provided between the side plate 2d and the rotating body 44 to press the rotating body 44 toward the wall 2n. The shaft 48 is rotatably supported by the side plate 2d of the base 2 and protrudes outward from the left side plate 2d. An operation plate 47 is attached to the protruding portion.

  The rotating body 44 is provided with an arm 44a and a stopper 44b. When the rotating body 44 is rotated from the initial position shown in FIGS. 25 (A) and 27 (A) to the locked position shown in FIGS. 25 (B) and 27 (B), the rotating body 44 moves the arm 44a to the wall. It rotates while sliding on the 2n inclined surface 51. At this time, since the inclined surface 51 protrudes more toward the side plate 2d side than the portion where the arm 44a at the initial position contacts, the portion where the arm 44a at the lock position contacts is pushed toward the side plate 2d. The spring 49 is compressed and moved to the side plate 2d side. A link 46 is swingably connected to the arm 44a. When the rotator 44 is returned from the locked position to the initial position, the stopper 44b comes into contact with the side plate 2d to prevent the rotator 44 from rotating too much.

  The oscillating body 45 includes left and right side plates 45a and 45b and a connecting plate 45c for connecting them. The left and right side plates 45a and 45b are provided with shaft portions 45d. The shaft portions 45d are inserted into the recesses 2p provided in the base 2, and the cover plate 52 is covered with the shaft portions 45d. By fixing to the base 2, the swinging body 45 is attached to the base 2 so as to be swingable about the shaft portion 45 d. The upper end of the rocking body 45 is located in front of the shaft portion 45d. Therefore, when the oscillating body 45 is oscillated backward, the upper end of the oscillating body 45 rises and fits into the recess 4 h of the back support 4. In this state, the upper end of the rocking body 45 has entered the region where the back support 4 is tilted backward.

  In the state where the rotating body 44 is returned to the initial position as shown in FIG. 25A, the link 46 raises the swinging body 45 forward, and the upper ends of the side plates 45a and 45b are the recesses 4h of the back support 4. It is off. That is, since the side plates 45a and 45b are disengaged from the backward tilt region of the back support 4, the back support 4 can be tilted backward. That is, the backrest 3 is not locked.

  On the other hand, when the rotating body 44 is rotated to the locked position as shown in FIG. 25 (B), the link 46 swings the swinging body 45 backward, so that the upper ends of the side plates 45a and 45b are recessed portions of the back support body 4. Fit into 4h. That is, since the side plates 45a and 45b enter the backward tilt region of the back support 4, the back tilt of the back support 4 is prohibited. That is, the backrest 3 is locked.

  25 to 28, the support plate 4c of the back support 4 is divided into a front part 4ca and a rear part 4cb. The front portion 4ca is formed by bending one plate material, and the rear portion 4cb is formed integrally with the left and right side plates 4a, 4b. That is, the rear portion 4cb and the side plates 4a and 4b are formed by bending one plate material. The front portion 4ca is fixed to the left and right side plates 4a and 4b by welding or the like, for example.

  In the embodiment shown in FIGS. 25 to 28, as shown in FIG. 42, the shaft support portion 20b of the operation lever 20 of the height adjusting mechanism 19 is dropped into the recesses of the two ribs 2i and 2i, and the ribs 2i and 2i. The lever 20 is rotatably supported by sandwiching the position between the two from above with a flat fixture 21.

Moreover, as the lock mechanism 23, you may employ | adopt what gave the self-holding function by interposing a spring part in a mechanism. For example, as shown in FIGS.
The link 46 absorbs a displacement that is elastically deformed to cause the swinging body 45 to swing when the operating means 44 is operated in a state where the swinging of the swinging body 45 is restricted, and accumulates a force. An elastically deformable portion (spring portion) 56 that exerts a force to swing the swinging body 45 when the swinging body 45 can swing may be provided. In the present embodiment, the elastic deformation portion 56 is provided by bending the link 46 in the middle of a U shape. However, the shape of the elastic deformation portion 56 is not limited to this, and a force that absorbs a displacement that causes the swinging body 45 to swing as described later and stores the force, or a force that swings the stored swinging body 45. The shape is not particularly limited as long as the shape can exhibit the above.

  In the present embodiment, the rotating body 44 as the operating means is disposed between the left side plate 2d of the base 2 and the wall 2n, and is fitted into the shaft 48 so as not to be relatively rotatable. That is, by inserting the convex portion 48 a provided on the shaft 48 into the concave portion 44 d of the hole 44 c provided on the rotating body 44, the rotating body 44 is fitted so as not to rotate relative to the shaft 48. A locking member 57 is provided between the rotating body 44 and the bottom plate 2 a of the base 2. The locking member 57 is molded from, for example, an elastic resin, and by providing a hole 57c, the convex portion 57d between the concave portions 57a and 57b can be pushed down. The protrusion 44e provided on the bottom surface of the rotating body 44 is fitted into the recess 57a or the recess 57b of the locking member 57, so that the rotating body 44 is locked at the initial position shown in FIG. 43 or the lock position shown in FIG. . The convex portion 44e of the rotating body 44 can move between the concave portion 57a and the concave portion 57b by pushing down the convex portion 57d. For this reason, the rotating body 44 can rotate between the initial position and the lock position. The locking member 57 is fitted in a recess 2 t provided in the bottom plate 2 a of the base 2.

  The rotating body 44 is provided with an arm 44a. A link 46 is swingably connected in the vicinity of the tip of the arm 44a. The opposite end of the link 46 is connected to the side plate 45b of the swinging body 45 so as to be swingable.

  The shaft 48 is inserted into a hole 58 provided in the side plate 2d of the base 2 and a hole 61 provided in the wall 2n. The inner end of the shaft 48 is freely rotatable by the wall 2w and a fixture 21 for swinging the operation lever 20. It is supported by. The shaft 48 is provided with a convex portion 48b. By inserting this convex portion 48b into the concave portion 58a of the hole 58 of the side plate 2d, the rotational angle of the shaft 48 is changed from the one side of the concave portion 58a to the opposite side. Is limited to the range up to the point of contact, that is, the range in which the rotating body 44 is rotated from the initial position to the lock position (FIG. 47). The base 2 is made of metal, for example, and the hole 58 or the recess 58a does not expand even when a force forcibly turning beyond the rotation range is input to the shaft 48, and the rotation angle of the shaft 48 can be limited. In addition, it is possible to prevent the rotating body 44 from rotating too much and the swinging body 45 from swinging excessively, and it is possible to prevent a load from being applied to the attachment portion at the inner end of the shaft 48.

  As shown in FIG. 48, the inner end of the shaft 48 is placed on a stepped portion 59 of the wall 2w. A groove 48c is formed in the vicinity of the inner end of the shaft 48. By inserting the locking piece 21a of the fixture 21 into the groove 48c from above, the inner end of the shaft 48 is connected with the wall 2w and the fixture 21. It is rotatably supported. Further, the shaft 48 can be prevented from coming off by inserting the locking piece 21a into the groove 48c. Since the shaft 48 is supported by the fixture 21 to which the operation lever 20 is swingably attached, the number of parts is reduced and the number of assembling steps is also reduced, so that the manufacturing cost can be reduced.

  An operation grip 60 is fixed to the outer end of the shaft 48. The rotating body 44 can be rotated by gripping and rotating the operation grip 60. However, instead of the operation grip 60, a lever (not shown) may be attached to the shaft 48, and the rotating body 44 may be operated by lever operation.

  The back support 4 of the present embodiment is provided with a convex portion 4i. The convex portion 4i is located outside the region where the swinging body 45 swings in a state where the back support 4 is not tilted backward, and is in a region where the swinging body 45 swings when the back support 4 tilts backward. enter in.

  In the state where the rotating body 44 is returned to the initial position as shown in FIG. 43, the link 46 pulls the swinging body 45 forward, and the upper ends of the side plates 45a and 45b are disengaged from the recess 4h of the back support 4. Therefore, as shown by an arrow T in FIG. 43, the back support 4 can be tilted backward. That is, the backrest 3 is not locked.

  On the other hand, when the rotating body 44 is rotated to the locked position as shown in FIG. 44, the link 46 swings the swinging body 45 backward. For this reason, the upper ends of the side plates 45 a and 45 b are fitted into the recesses 4 h of the back support 4. If the back support 4 is tilted backward in this state, the back support 4 hits the swinging body 45, and therefore the back support 4 is not tilted backward. That is, the backrest 3 is locked.

  When the rotating body 44 is in the initial position and the swinging body 45 is pulled back forward, if the back support 4 is tilted backward as shown by an arrow T in FIG. 43, the convex portion 4i of the back support 4 swings. The moving body 45 enters the swinging region. If the operating grip 60 is operated in this state to slightly swing the swinging body 45 backward, the swinging body 45 hits the convex portion 4i, and thereafter the swinging body 45 cannot swing back. When the operating grip 60 is further operated in this state to further rotate the rotating body 44, the elastic deformation portion 56 of the link 46 elastically deforms and absorbs the displacement that causes the swinging body 45 to swing, so that the operating force is increased. accumulate. Then, when the back support 4 tilted rearward in this state is raised, the convex portion 4i is detached from the swinging region of the swinging body 45, and the swinging body 45 can be swung back. The deformed elastic deformation portion 56 exerts the accumulated operation force while returning to its original shape, and swings the swinging body 45 backward. In this way, even if the locking operation is performed in a state where the backrest 3 cannot be locked, the rocking body 45 will not be rocked forcibly, so that the structural members can be prevented from being damaged. Further, even when the swinging body 45 cannot swing, the operation of rotating the rotating body 44 can be performed, and the swinging body 45 is automatically swinged when the swinging becomes possible. The operation can be performed without worrying about whether or not it is tilted. For these reasons, the usability of the chair can be further improved.

  Further, when the seat back rests on the backrest 3 when the backrest 3 is locked by the lock mechanism 23 (the state shown in FIG. 44), that is, the swinging body 45 is swung back and the side plates 45a, 45b When the back support 4 is tilted backward with the upper end fitted in the recess 4h of the back support 4, the support plate 4c of the back support 4 hits the swinging body 45, so that the support plate 4c is so-called the swinging body. Thus, the rocking body 45 cannot be pulled back forward. In this state, when the operating grip 60 is operated to rotate the rotating body 44 to the initial position, the elastic deformation portion 56 of the link 46 elastically deforms and absorbs the displacement that causes the swinging body 45 to swing, thereby operating force. Accumulate. If the seated person stops leaning on the backrest 3 in this state, the support plate 4c can be separated from the swinging body 45 and the swinging body 45 can be pulled back. The portion 56 exerts the accumulated operating force while returning to its original shape, and pulls the rocking body 45 forward. Thus, even if the unlocking operation is performed in a state in which the backrest 3 cannot be unlocked, the rocking body 45 is not rocked forcibly, so that the structural members can be prevented from being damaged. Further, even when the swinging body 45 cannot swing, the operation of rotating the rotating body 44 can be performed, and the swinging body 45 is automatically swinged when the swinging becomes possible. The operation can be performed without worrying about whether or not it is tilted. For these reasons, the usability of the chair can be further improved.

  Further, as shown in FIGS. 29 to 31, a seat shell 38 may be screwed to a seat fitting as the seat support 6. That is, the seat support 6 may be disposed in the recess 38a of the seat shell 38, and both may be fixed using the screws 54.

  Further, as shown in FIGS. 32 and 33, the seat shell 38 may be screwed to a seat receiving bracket as the seat support 6, and an elbow mounting bracket 39 may be fixed to the seat support 6 by welding or the like. . That is, the seat support 6 may be disposed in the recess 38a of the seat shell 38, and both may be fixed using screws 54, and an elbow mounting bracket 39 may be provided to enable armrest mounting.

  Further, as shown in FIGS. 34 to 36, a seat mounting bracket 37 may be fixed to a seat receiving bracket as the seat support 6 by, for example, welding or the like, and a seating plate 55 may be screwed to the seat mounting bracket 37. .

  Further, as shown in FIGS. 37 and 38, the second swing center shaft 8 and the third swing center shaft 9 are extended, and the second swing center shaft is formed by a seat reinforcing metal fitting as the seat support 6. 8 and the third swing center shaft 9 are connected, and a hook 38 b is formed on the seat shell 38, and the hook 38 b is hooked on the second swing center shaft 8 and the third swing center shaft 9. Thus, the seat shell 38 may be assembled to the seat support 6.

It is a side view of the state which shows 1st Embodiment of the chair of this invention, and the backrest is not inclined backward. It is a side view of the state which made the backrest of the chair tilt backward. The base, back support, and seat support of the chair are shown, (A) is a cross-sectional view of the state where the back support is not tilted backward, and (B) is a cross-sectional view of the state where the back support is tilted backward. is there. It is a top view of the state which assembled | attached the back support body to the base. It is a figure for demonstrating a height adjustment mechanism, and is sectional drawing which follows the VV line of FIG. It is sectional drawing which expands and shows the attachment part of the operation lever of a height adjustment mechanism. It is a side view which shows 2nd Embodiment of the chair of this invention. It is a top view which shows the locking mechanism of the chair. It is sectional drawing of the knock mechanism of the chair which operates a locking mechanism. It is a figure which shows a mode that the gas spring for height adjustment is operated. It is sectional drawing for demonstrating attachment of an operation member. It is the figure which looked at a mode that the seat mounting bracket was fixed to the seat support body from the front of the chair. It is the figure which looked at a mode that the elbow mounting bracket was fixed to the seat support body from the front of the chair. It is a figure for demonstrating the action | operation of a knock mechanism, and is a conceptual diagram of the state which does not protrude the convex part. It is a figure for demonstrating the action | operation of a knock mechanism, and is a conceptual diagram which shows the state following FIG. FIG. 16 is a diagram for explaining the operation of the knock mechanism, and is a conceptual diagram showing a state following FIG. 15. It is a figure for demonstrating the action | operation of a knock mechanism, and is a conceptual diagram which shows the state following FIG. It is a figure for demonstrating the action | operation of a knock mechanism, and is a conceptual diagram which shows the state following FIG. It is a figure for demonstrating the action | operation of a knock mechanism, and is a conceptual diagram which shows the state following FIG. It is a figure for demonstrating the action | operation of a knock mechanism, and is a conceptual diagram which shows the state following FIG. It is a figure for demonstrating the action | operation of a knock mechanism, and is a conceptual diagram which shows the state following FIG. It is a side view which shows other embodiment of a slide mechanism. It is a side view which shows other embodiment of the reaction force mechanism. It is a side view which shows other embodiment of the reaction force mechanism. Other embodiment of a lock mechanism is shown, (A) is sectional drawing of the state which has not latched the back support body, (B) is sectional drawing of the state which has latched the back support body. It is a top view of the lock mechanism. The rotary body of the lock mechanism is shown, (A) is a view of the state where the back support is not locked, as viewed from the front side of the chair, and (B) is the state where the back support is locked. It is the figure seen from the front side. It is sectional drawing which shows a mode that the rocking body of the lock mechanism is attached to a base. It is the bottom view of the 1st pattern which shows the typical attachment structure of a seat. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which follows the BB line of FIG. It is the bottom view of the 2nd pattern which shows the typical attachment structure of a seat. It is sectional drawing which follows the AA line of FIG. FIG. 5 is a bottom view of a third pattern, showing a representative mounting structure of a seat. It is a side view of the attachment structure of FIG. It is a front view of the attachment structure of FIG. FIG. 10 is a top view of a fourth pattern, showing a typical mounting structure of a seat. It is sectional drawing which follows the AA line of FIG. It is a graph which shows the mode of a change with the back inclination angle of a backrest, and the height of a seat. It is a graph which shows the mode of a change with the back inclination angle of the backrest, and the reaction force to generate | occur | produce. FIG. 9 shows a cross section along line XX in FIG. 9, (A) is a cross-sectional view of a state in which the gas spring for height adjustment is not operated, and (B) is a state in which the gas spring for height adjustment is operated. FIG. It is sectional drawing which shows other embodiment of the attachment structure of the operation lever of a height adjustment mechanism. It is sectional drawing of the state which shows other embodiment of a locking mechanism, and has not latched the back support body. It is sectional drawing of the state which shows the lock mechanism and has latched the back support body. It is a top view of the lock mechanism. It is sectional drawing which follows the XX line of FIG. It is sectional drawing which follows the YY line of FIG. It is sectional drawing which follows the ZZ line | wire of FIG. It is a side view of the state which shows the conventional chair and the backrest is not inclined backward. It is a side view of the state which made the backrest of the chair tilt backward.

Explanation of symbols

1 leg 2 base 3 backrest 4 back support 5 seat 6 seat support 7 first swing center shaft 8 second swing center shaft 9 third swing center shaft 10 slide mechanism 14 reaction force mechanism 23 lock mechanism 44 Rotating body (operating means)
45 Oscillator 46 Link 56 Elastic deformation portion L Line connecting the first oscillation center axis and the second oscillation center axis as seen from the width direction of the chair

Claims (3)

A leg, a base supported by the leg, a back support to which a backrest is attached, a seat support to which a seat is attached, and a first support for connecting the back support to the base so as to be tilted backward. Displacing above the first swing center axis and above the first swing center axis and above the first swing center axis and above the first swing center axis, A second swing center shaft that connects the seat support to the base so as to be swingable in a vertical direction; and between the first swing center axis and the second swing center axis. Displace above a line connecting the first swing center axis and the second swing center axis, and connect the back support and the seat support so as to be swingable in the vertical direction; A third swing center axis that rises in conjunction with the back tilt of the back support, and the second swing center that moves in conjunction with the rise of the third swing center axis The includes a sliding mechanism which guides the rear obliquely upward, the slide mechanism is adapted to the arc to guide which is convex to the second swing center axis linearly or lower, the backward tilting of the backrest At this time, the rate of increase of the second oscillation center axis is made uniform from the beginning to the end of the rearward tilt, or the rate of increase of the second oscillation center axis is gradually increased as the backrest tilts backward. chair characterized by large Do Rukoto. The chair according to claim 1 , further comprising a lock mechanism that locks the back support with respect to the base . The lock mechanism includes an oscillating body that locks the back support, a link that oscillates the oscillating body, and an operating unit that displaces the link. The link restricts the oscillation of the oscillating body. When the operation means is operated in a state of being operated, the force is accumulated by absorbing the displacement that is elastically deformed to swing the swinging body, and when the swinging body is allowed to swing, The chair according to claim 2, further comprising an elastically deformable portion that exerts a force for swinging the swinging body .

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