Reclining chair

Abstract

To disclose a structure of a changeover mechanism with excellent operability concerning a chair where a backward inclination of a backrest is controlled by a gas cylinder.SOLUTION: A changeover mechanism unit 23 includes: a pusher 36 to be drawn by a wire 49; a rotor 37 to be pushed by the pusher 36; a spring 38; a guide case 39 to which a rocking link 35 is fitted-in; and a first bracket 32 incorporating a fixed cam part. Whenever the wire 49 is drawn once, the rotor 37 is intermittently rotated so as to be exchanged between an advance state and a retreat state. Then, the state is exchanged between a backward rotation state of the rocking link 35 and a forward return rotation state of the rocking link 35 via the guide case 39.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a reclining chair whose backrest reclines backward, and more particularly to a chair that controls reclining with a gas cylinder.

Background Art

[0002] In a reclining chair, as a method of controlling the backward tilt of the backrest, there are a method of adjusting the posture step by step using a cam mechanism or the like, and a method of adjusting the backward tilt posture steplessly using a gas cylinder. The latter method has the advantage that it can be adjusted to suit the user's preference.

[0003] When controlling reclining with a gas cylinder, it is necessary to push the push valve of the gas cylinder to hold it in the unlocked state (free state) or to return the push valve to hold it in the locked state. Regarding this operation, there are a method of directly pushing down the push valve with a lever and a method of using a wire inserted into a tube. An example of the wire method is disclosed in Patent Document 1.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] Now, when controlling the raising and lowering of the seat, the lock of the gas cylinder is released only when the lever is pulled. When a person removes their fingertips from the lever, the lever returns to its original position. However, for the gas cylinder for reclining, in a structure where the push valve is only pushed by lever operation as in Patent Document 1, it is necessary to hold the lever in the locked position and the unlocked position.

[0006] And since the lever is generally rotatable, it is tilted downward and rotated or lifted upward and rotated. However, since the user often does not remember the posture of the lever, there is a risk that the user will strongly apply force to rotate the lever in the opposite direction to the original direction, thereby applying a large load to the lever.

[0007] In addition, the above-described lifting lever of the seat is often arranged on the side portion of the seat, and generally, it is often raised upward to release the lock. Therefore, in the normal state where the lever is not used, the lever is in a downward posture. However, since the reclining control lever is held in either a downward posture or an upward posture, there is a concern that the lifting operation lever and the reclining control lever may be in a non-uniform state, resulting in a poor appearance.

[0008] Furthermore, regarding the reclining lever, it is also rotated around the left-right longitudinal axis so that forward rotation operation and reverse rotation operation can be easily performed. In this case, since the rotation direction of the reclining lever is different from the rotation direction of the lifting (height adjustment) lever, the problem of appearance becomes prominent.

[0009] The present invention has been made in view of such a situation, and an object thereof is to provide a reclining chair having an improved switching mechanism.

Means for Solving the Problems

[0010] The present invention includes the configurations of each claim. Among them, the invention of claim 1 forms a superordinate concept, "a base supported by a leg device, a back frame connected to the base so as to be tiltable backward, a backrest provided on the back frame, a tilting control gas cylinder for switching the back frame between a tiltable state and a non-tiltable state, and an operating device operated by a seated person for switching the tilting control gas cylinder between a locked state and an unlocked state, The operating device includes an operating member operated by a seated person, a wire connected to the operating member, and a switching mechanism unit that alternately switches the tilting control gas cylinder between a locked state and an unlocked state each time the wire is pulled once. It has such a configuration.

[0011] Claim 2 is a development example of Claim 1, "When not in operation, the operating member has the same posture in the locked state and the unlocked state." It has such a configuration. In this case, the operating member is preferably held in the same posture by a spring, but it is also possible to hold it in the same posture by using its own weight.

[0012] The invention of Claim 3 specifies the structure of the chair. In Claim 1 or 2, "The lower part of the back frame branches into two branches, and the front ends of the bifurcated parts are connected to the base, The tilting control gas cylinder is arranged so as to enter the bifurcated part of the back frame in an inclined posture that rises backward, The switching mechanism unit of the operating device is arranged at the lower end of the tilting control gas cylinder." It has such a configuration.

[0013] The invention of Claim 4 is a preferred development example of the switching mechanism unit. In Claim 1 or 2, "The switching mechanism unit of the operating device has a first operating member (pusher) that moves against a spring in the axial direction of the tilting control gas cylinder by pulling the wire, and a second operating member (rotary cam) that rotates by the movement of the first operating member. By the rotation of the second member, the tilting control gas cylinder is set to alternately switch between a free state and a locked state." It has such a configuration.

[0014] The invention of Claim 5 relates to the arrangement of the wire. In Claim 1 or 2, "In the operation device, the wire is drawn out from the switching mechanism portion to the rear side." It has such a configuration.

[0015] The invention of claim 6 is a development example of claim 3, "The operation device includes a bracket to which the front end of the tilting control gas cylinder is fixed, and a cover that covers the bracket from below, The bracket is connected to a rib provided at the rear end of the base by a horizontally long pin, and the pin is held by the cover so as not to be movable left and right." It has such a configuration.

[0016] The invention of claim 7 is a development example of claim 6, "The bracket has a structure in which an upper bracket through which the pin is inserted and a lower bracket to which the tilting control gas cylinder is fixed are overlapped, and the first operating member, the second operating member, and the spring are arranged in a space surrounded by the upper bracket and the lower bracket." It has such a configuration.

Advantages of the Invention

[0017] In the present invention, each time the wire is pulled once, the gas cylinder switches between the locked state and the unlocked state. Therefore, an operating member such as a lever only needs to be operated by turning it in one direction. Accordingly, a person sitting does not need to check the posture of the operating member one by one, and only needs to simply move the fingertip against the operating member. Therefore, the reclining state can be easily switched, which is user-friendly.

[0018] Furthermore, since the operating member only needs to be moved in one direction, the freedom of design can also be improved when attaching the operating member to the chair. It is also easy to achieve a design unity with the lever for lifting operation.

[0019] For example, if the operating member is a rotating lever, it is easy to limit the direction of rotation so that it can only be rotated by pulling it up, but there may be cases where the operating member is made into a rotating handle due to design requirements. In this case, the present invention allows the gas cylinder to be controlled whether the handle is rotated forward or backward, so the user will not be confused and it is easy to operate (in this case, it is preferable to set it so that it returns to the neutral position whether it is rotated forward or backward). The same applies to rotating levers.

[0020] By adopting the configuration of claim 2, the operating member is always maintained in the same posture when not in operation, which is convenient because a seated person can operate it without hesitation, and the design is unified and looks good.

[0021] In the configuration of claim 3, the front end of the back frame is connected to the base at two points, the left and right, so stability can be significantly improved. In addition, the forked part of the back frame also serves as a cover to hide the gas cylinder, so it looks good and prevents objects from hitting the gas cylinder. Furthermore, the switching mechanism is located at the bottom end, so the wide open space can be effectively used.

[0022] In the configuration of claim 4, the second operating member is a kind of rotary cam, so its movement is smooth and the gas cylinder can be easily switched. Since the wire is simply pulled, it can be easily applied even when the operating member is a forward / reverse rotating lever or a forward / reverse rotating handle. In other words, the gas cylinder can be switched to the desired state by rotating it in either direction.

[0023] Now, since the wire is inserted into the tube, there is a limit to the radius at which it can be bent, but in claim 4, there is an open space behind the operating device, so the wire can be bent loosely and pulled without resistance. Also, if the wire (tube) is passed through the fork in the center frame from below, the fork can be used to prevent the wire from sagging.

[0024] In claim 6, since the detachment of the pivot pin can be prevented by the cover, the number of components can be suppressed and the workability can also be improved. In the invention of claim 7, the upper and lower brackets are effectively utilized as a casing, and the switching mechanism part can be unitized. Therefore, it can contribute to the improvement of the workability of assembly and the quality can also be stabilized.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0026] Next, embodiments of the present invention will be described with reference to FIGS. 1 to 11. In the following description, the terms "front and back" and "left and right" are used to specify directions. However, these terms of front and back and left and right are based on a seated person. The front view direction is the direction facing the seated person. Therefore, the left and right in the front view are opposite to the left and right seen from the seated person.

[0027] Next, embodiments of the present invention will be described with reference to the drawings. In the following, the terms "front and back" and "left and right" are used to specify directions. However, this direction is defined as the direction seen from a person normally sitting on a chair. The front view is a view seen from the direction facing the seated person.

[0028] (1). Basic structure of the chair First, the outline of the chair will be described mainly with reference to FIGS. 1 and 2. This embodiment is applied to a swivel chair frequently used in offices. The chair mainly includes a leg device 1, a seat 2, and a backrest 3 as basic elements. The leg device 1 has a structure in which a leg column 4 made of a gas cylinder is erected at the center of a base having five leg blades, and casters are provided at the tips of each leg blade.

[0029] A base 5 is fixed to the upper end of the leg column 4. The lower ends of the left and right first tilting frames 6 are connected to the base 5 by a first reference support shaft 7. For example, as shown in FIG. 1(B), the first tilting frame 6 extends backward while spreading outward from the base 5 to the left and right, and then rises upward. The portion that rises upward and spreads greatly outward to the left and right constitutes a lower side member 8a of the lower back frame 8.

[0030] The lower ends of the lower side members 8a constituting the lower back frame 8 are connected by a lower member 8b having a left-right longitudinal direction. That is, the lower back frame 8 is constituted by connecting the rising portions of the left and right first tilting frames 6 with the lower member 8b. An upper back frame 9 that forms a back frame device integrally with the lower back frame 8 is disposed on the lower back frame 8. The upper back frame 9 is configured in a loop shape that is open front and back.

[0031] As shown in Fig. 1(B), the middle member 9a of the upper back frame 9 projects rearward, and the upper ends of the vertically long second tilting frame (center frame) 12 are connected to the left and right middle parts of the rearward-projecting middle member 9a so as to be tiltable rearward by a third reference support shaft (not shown) in the longitudinal direction. The tilting frames 6 and 12 constitute the back frame described in the claims.

[0032] As clearly shown in Fig. 2, the lower end portion of the second tilting frame 12 is a bifurcated portion 12a having left and right parts, and the front end (lower end) of the bifurcated portion 12a is connected to a bearing block 5a provided at the rear end of the base 5.

[0033] That is, a support shaft 13 is inserted through the front end of the bifurcated portion 12a, and the support shaft 13 is sandwiched between split bushings 14 and 15 from above and below. The split bushings 14 and 15 are fitted into a long groove 16 of a bearing block 5a formed so as to project from the rear end of the base 5, and are pressed and fixed by a cover plate 17. The cover plate 17 is fixed to the base 5 by screws 18.

[0034] Flanges 19 for preventing displacement are formed at both the left and right ends of the split bushings 14 and 15, and the support shaft 13 is held in a non-removable manner at the rear end portions of the left and right side plates 5b constituting the base 5.

[0035] In this embodiment, the first tilting frame 6, the second tilting frame 12, and the back frames 8 and 9 rotate relative to each other while tilting rearward as a whole. However, due to differences in the front and rear positions and vertical heights of the respective support shafts 7, during reclining, the upper back frame 9 rotates forward relative to the lower back frame 8 (and the first tilting frame 6).

[0036] A top rest device 3a is attached to the upper end of the upper backrest 9. When reclining, the upper backrest 9 rotates forward relative to the lower backrest 8, so that in the reclined state, the user's head can be held in a state raised by the top rest device 3a. Therefore, the user of the chair can relax the body and look at the computer on the desk in a natural state, and perform computer operations such as keyboard operations and mouse operations.

[0037] As shown in FIG. 2, a tilting control gas cylinder 20 is disposed between the bifurcated portions 12a of the second tilting frame 12. The tilting control gas cylinder 20 is in an inclined posture so as to become higher toward the rear, and the hook portion 21 at the rear end (upper end) thereof is connected to a bearing bracket 22 provided on the second tilting frame 12 by an upper pin 21a in the longitudinal direction of the left and right.

[0038] A switching mechanism unit 23 is attached to the lower end portion of the tilting control gas cylinder 20, and the switching mechanism unit 23 is connected to a bearing rib 25 provided on a bearing block 5a of the base 5 by a lower pin 24 in the longitudinal direction of the left and right. Therefore, by controlling the tilting control gas cylinder 20, the backrest 3 can be freely tilted forward and backward or fixed in an arbitrary posture.

[0039] The seat 2 is attached to a seat outer shell 26. The rear portion of the seat outer shell 26 is connected to an outwardly extending branch portion 6a provided on the first tilting frame 6, and the front portion of the seat outer shell 26 is slidably and non-removably connected to the front portion of the base 5 in the front-rear direction. When the backrest 3 reclines, the seat 2 reclines while moving backward. As shown in FIG. 1(C), a tilting adjustment lever 27, which is an example of an operating member for operating the switching mechanism unit 23, is connected to the seat outer shell 26 so as to be pivotable upward.

[0040] In front of the tilting adjustment lever 27, there is an elasticity adjustment handle 28 for adjusting the reclining resistance. As shown in FIGS. 1(A) and 1(B), on the left side of the seat outer shell 26, there are arranged a lifting operation lever 29 and a seat depth adjustment handle 30. The lifting operation lever 29 is attached so as to pivot upward. Next, the switching mechanism unit 23 will be described.

[0041] (2). Switching mechanism unit For example, as shown in FIGS. 5 and 6, the switching mechanism unit 23 includes a first bracket 32 to which the rod 31 of the tilting control gas cylinder 20 is attached, a second bracket (second case) 33 covering the first bracket (first case) 32 from above, a cover 34 fitted to these brackets 32 and 33 from below, a swing link 35 connected to the second bracket 33 so as to pivot back and forth with its upper end as a fulcrum, and a pusher 36, a rotor 37, a spring 38, and a guide case 39 arranged in a row inside the first bracket 32.

[0042] The first bracket 32 is roughly in the shape of a rectangular cylinder with positioning holes 32a in the tip plate, and inside it, there are arranged a pusher 36, a rotor 37, a spring 38, and a guide case 39. At the rear end of the first bracket 32, an upward plate 32b projects upward, and the rod 31 of the tilting control gas cylinder 20 is screwed into the upward plate 32b, and the rod 31 is fixed to the upward plate 32b with a nut 31a. The rear end of the first bracket 32 is open in a D shape, and the pusher 36, the rotor 37, and the spring 38 are inserted from the rear end.

[0043] At the upper end of the front-protruding part of the first bracket 32, L-shaped engaging ribs 40 with their front ends formed as engaging hook parts 40a project left and right. On the other hand, the second bracket 33 has a U-shaped form in plan view with left and right side plates 33a and a rear plate 33b, and the lower pin 24 is inserted through the side plate 33a. Further, on the outer surfaces of the lower ends of the left and right side plates 33a, engaging grooves 41 into which the engaging ribs 40 of the first bracket 32 can enter are formed, and hook parts 41a are formed at the front ends of the engaging grooves 41. Therefore, when the second bracket 33 is overlapped on the first bracket 32 from above and slid backward, the upper and lower brackets 32, 33 are held in a state where they do not separate vertically.

[0044] For example, as shown in FIG. 5(C), a U-shaped bearing groove 42 is formed at the rear end of the side plate 33a of the second bracket 33, and a support shaft 43 provided at the upper end of the swing link 35 is fitted into the bearing groove 42 from above. Therefore, the swing link 35 rotates back and forth with the support shaft 43 as a fulcrum, and by this rotation, the push valve 44 of the tilting control gas cylinder 20 is pushed or retracted. The push valve 44 is elastically biased in the protruding direction, but the elastic force of the spring 38 of the switching mechanism part is set to be smaller than the elastic force of the push valve 44.

[0045] In this case, as shown in FIG. 5(C), the support shaft 43 of the swing link 35 is cut so as to have two flat surfaces, and the flat surfaces are set to be parallel to the rear surface of the second bracket 33 in a posture raised above the use state, while the bearing groove 42 is formed in a form with the upper part constricted. Therefore, when the swing link 35 is set in a posture raised from the use posture and the support shaft 43 is inserted into the bearing groove 42 from above, and then the swing link 35 is tilted downward to shift to the use posture, the swing link 35 is held in the bearing groove 42 so as not to come out. Therefore, the attachment of the swing link 35 can be performed in one touch.

[0046] For example, as shown in Fig. 4(A), L-shaped thick portions 33c are integrally formed on the left and right side surfaces of the second bracket 33 so as to project left and right. On the other hand, the cover 34 has a height that reaches the upper end of the second bracket 33 beyond the first bracket 32, and an overhanging portion 34a that overlaps the thick portion 33c of the second bracket 33 is formed. Further, the rear end plate 34b of the cover 34 is in close contact with the rear surface of the first bracket 32 from behind. Therefore, the first bracket 32 and the cover 34 are held in a non-displaceable manner in the front-rear, left-right directions.

[0047] And, pocket portions 45 for holding the exposed portions of the lower pins 24 are formed on the left and right side plates of the cover 34 in an upwardly open state. Therefore, the cover 34 and the second bracket 33 are held in a non-displaceable manner in the front-rear direction. However, the second bracket 33 is in a state where it is slid backward after being overlapped on the first bracket 32, and the lower pins 24 are held by the pocket portions 45 of the cover 34. Therefore, the first bracket 32 and the second bracket 33 are held in a non-separable manner in the up-down, left-right, front-rear directions.

[0048] The lower pins 24 are inserted into the bearing ribs 25 shown in Fig. 3(C). However, by inserting the lower pins 24 into the bearing ribs 25 and then fitting the cover 34 onto the first bracket 32 and the second bracket 33 from below, the lower pins 24 are held in a non-removable manner.

[0049] For example, as shown in Fig. 4(A), the pocket portion 45 of the cover 34 is provided with front engaging claws 46 that engage with the upper ends of the lower pins 24. Therefore, by elastically deforming the front engaging claws 46, the exposed end portions of the lower pins 24 can be accommodated in the pocket portions 45. On the other hand, for example, as shown in Figs. 4(A)(B) and 6(A), the rear plate of the cover 34 is provided with a pair of left and right rear locking claws 47 that extend obliquely forward and downward in a side view, and the rear locking claws 47 are engaged with the rear ends of the second bracket 33 from above.

[0050] Therefore, when the cover 34 is pushed in from below against the set of the first bracket 32 and the second bracket 33 that overlap each other, the rear locking claw 47 elastically deforms and then engages with the second bracket 33. Therefore, the cover 34 is held so as not to fall, and the first bracket 32 and the second bracket 33 are also held so as not to move away from each other vertically.

[0051] As shown in FIG. 5(A), a slit groove 48 that opens upward is formed in the rear end plate 34b of the cover 34. On the other hand, a wire 49 (see FIG. 5(B)) pulled by the tilt adjustment lever 27 described above is inserted into a tube (not shown), and a fitting 50 with an annular groove fixed to the end of the tube is fitted into the slit groove 48 of the cover 34.

[0052] (2). Switching mechanism unit As shown in FIGS. 7(A) to 7(C), the pusher 36 is basically cylindrical, and a plurality of (six) vertical ribs 51 are formed on the outer peripheral surface at equal intervals. A partition wall 52 is formed inside, and wire insertion grooves 53 are formed in the peripheral wall and the partition wall 52, and a ball 54 connected to the wire 49 is placed against the front surface of the partition wall 52. An uneven surface 55 in which triangular ridges and valleys are continuous is formed at the rear end of the peripheral wall of the pusher 36. The number of ridges (or valleys) of the uneven surface 55 is the same as the number of vertical ribs 51, and the apex of each ridge is located at the position of the vertical rib 51.

[0053] On the other hand, the rotor 37 is in the form of a complete cylinder, and a spring 38 is inserted therein. The spring 38 is interposed between the partition wall 52 of the pusher 36 and the front surface of the guide case 39. The rotor 37 is provided with a small-diameter portion 37a that fits into the pusher 36, and a plurality of (three) guide ribs 56 are formed on the outer peripheral surface of the rotor 37. The tip of the guide rib 56 is an inclined surface (cam surface) 57 whose height changes in the circumferential direction. The guide rib 57 reaches the small-diameter portion 37a. Therefore, the inclined guide surface 56 of the guide rib 56 is in contact with the uneven surface 55 of the pusher 36.

[0054] For example, as shown in FIG. 6, a space portion 32c for storing the pusher 36 and the rotor 37 is formed in the first bracket 32. However, as shown in FIGS. 7(A) and 4(C), a thick portion 58 is formed on the inner peripheral surface of the space portion 32c in the first bracket 32. A plurality of (three each) axially long first cut grooves 59 and second cut grooves 60 are alternately formed in the thick portion 58. The second cut groove 60 completely divides the thick portion 58, but the first cut groove 59 is slightly shallower than the second cut groove 60.

[0055] The vertical rib 51 of the pusher 36 is slidably fitted into the first and second cut grooves 59 and 60. On the other hand, the guide rib 56 of the rotor 37 can be freely changed between a state of being fitted into the second cut groove 60 and a state of abutting against the rear end of the thick portion 58 when the rotor 37 rotates. Exactly, since three second cut grooves 60 are formed, the rotor 37 switches between a state of being fitted into the second cut groove 60 and a state of abutting against the rear end of the thick portion 58 every time it rotates 60°. Therefore, the first bracket 32 constitutes a fixed cam body.

[0056] For example, as shown in FIG. 6(A), the guide case 39 has a box-like form that opens upward and has front and rear walls. The lower end portion of the swing link 35 enters the inside of the guide case 39, and the lower end of the swing link 35 abuts against the front wall of the guide case 39 from the rear. Notch grooves 61 for inserting the wire 49 are formed in the front and rear walls of the guide case 39 and the lower end of the swing link 35, respectively.

[0057] (3). Summary Now, while the pusher 36 and the rotor 37 are biased forward by the spring 38, the push valve 44 of the tilting control gas cylinder 20 abuts against the swing link 35. The rotor 37 alternately switches between the forward state and the backward state by the guide rib 56 being fitted into and disengaged from the second cutout groove 60 of the first bracket 32 by intermittent rotation of 60° each time. When the rotor 37 moves backward, the guide case 39 is pushed backward and the swing link 35 rotates backward. Then, the push valve 44 of the tilting control gas cylinder 20 moves backward, and the tilting control gas cylinder 20 is released from the locked state. Therefore, the backrest 3 can be freely tilted forward and backward.

[0058] On the other hand, since the forward biasing force of the push valve 44 acts on the swing link 35, in the state where the rotor 37 has advanced (locked state), the swing link 35 is pushed by the push valve 44 and rotates forward, and the guide case 39 also advances. Therefore, the tilting control gas cylinder 20 is held in the locked state, and the backrest 3 is held unable to tilt backward.

[0059] For example, in the state where the rotor 37 has advanced (locked state), when the seated person raises the tilting adjustment lever 27 and pulls the wire 49 once, the rotor 37 is moved backward by the pusher 36 and the guide case 39 is also moved backward. However, when the uneven surface 55 of the pusher 36 and the inclined guide surface 57 of the rotor 37 come into contact, the rotor 37 rotates 60° under the guiding action of the pusher 36. Then, the inclined guide surface 57 of the rotor 37 abuts against the rear end of the thick portion 58 in the first bracket 32, and the rotor 37 and the guide case 39 are held in the backward state. As a result, the swing link 35 rotates backward and the tilting control gas cylinder 20 is released from the locked state.

[0060] When the rotor 37 is in the retracted state and the seated person raises the tilting adjustment lever 27 and pulls the wire 49 once, the retracting rotor 37 slightly retracts against the pressing force of the push valve 44, but the rotor 37 retracts while rotating 60° under the guiding action of the pusher 36. Then, when the seated person releases their hand from the tilting adjustment lever 27 and the pusher 36 retracts by the spring 38, the rotor 37 enters the advancing state as its guide rib 56 enters the second cutout groove 60 of the first bracket 32. Then, the swing link 35 is pushed by the push valve 44 and rotates forward, and the guide case 39 also advances.

[0061] In this way, by operating the tilting adjustment lever 27 once to pull the wire 49 once, the rotor 37 rotates intermittently and switches between the advancing state and the retracting state. Therefore, the seated person can switch the backrest 3 between the locked state and the free state simply by operating the tilting adjustment lever 27 to cause it to move. Therefore, the operability is excellent. Further, since the tilting adjustment lever 27 is held in the downward rotation posture by the spring 38, it has the same posture in both the locked state and the free state, and thus looks good.

[0062] In the embodiment, the switching mechanism unit 23 is in a bulged state below the tilting control gas cylinder 20. With this configuration, the members can be appropriately arranged by effectively using the space that expands downward. Also, the wire 49 is pulled backward from the switching mechanism unit 23 and connected to the tilting adjustment lever 27. Since the wire 49 is bent upward to reach the tilting adjustment lever 27, sagging can be prevented and it looks good. Using a rotor 37 like that in the embodiment as the switching mechanism enables compactification and is suitable.

[0063] In this embodiment, the switching mechanism unit 23 is pre - attached to the tilting control gas cylinder 20 to form a gas cylinder unit as a whole. Therefore, the workability of assembling the chair can be improved.

[0064] The embodiments of the present invention have been described above, but the present invention can be embodied in various other ways. For example, as the specific structure of the switching mechanism unit, a mechanism using a heart cam or the like can also be adopted. Further, a rotary handle can also be adopted as the operation member.

[0065] Also, the structure of the back frame can be embodied in various ways. For example, a structure in which a backrest is attached to a back support located at the left and right middle parts, or a structure without a center frame can also be adopted. It is also possible to connect the left and right frames with stays and connect the tilting control gas cylinder to the stays. The back frame can also adopt an outer shell structure.

Industrial Applicability

[0066] The present invention can be embodied in a reclining chair. Therefore, it can be used industrially.

Explanation of Signs

[0067] 1 Leg device 2 Seat 3 Backrest 5 Base 6 First tilting frame 12 Second tilting frame (back frame in the claims) 20 Tilting control gas cylinder 23 Switching mechanism unit 21a Upper pin 24 Lower pin 27 Tilt adjustment lever, an example of the operation member 31 Rod 32 First bracket 33 Second bracket 34 Cover 35 Rocking link 36 Pusher 37 Rotor 38 Spring 39 Guide case 49 Wire 51 Vertical rib 54 Ball 55 Concave-convex surface 56 Guide rib 57 Inclined guide surface 58 Thick portion (fixed cam portion) 59, 60 Split groove

Claims

1. A base supported by a leg device, a back frame pivotally connected to the base so as to be tiltable backward, a backrest provided on the back frame, a tilt control gas cylinder for switching the back frame between a tiltable state and a non-tiltable state, and an operating device operated by a seated person for switching the tilt control gas cylinder between a locked state and an unlocked state. The operating device includes an operating member operated by a seated person, a wire connected to the operating member, and a switching mechanism unit that alternately switches the tilt control gas cylinder between a locked state and an unlocked state each time the wire is pulled once. A reclining chair.

2. When not in operation, the operating member is in the same posture in the locked state and the unlocked state. The reclining chair according to Claim 1.

3. The lower part of the back frame is bifurcated, and the front ends of the bifurcated parts are connected to the base. The tilt control gas cylinder is arranged so as to enter the bifurcated part of the back frame in an inclined posture that rises backward. The switching mechanism unit of the operating device is arranged at the lower end of the tilt control gas cylinder. The reclining chair according to Claim 1 or 2.

4. The switching mechanism unit of the operating device has a first operating member (pusher) that moves against a spring in the axial direction of the tilt control gas cylinder by pulling the wire, and a second operating member (rotary cam) that rotates by the movement of the first operating member. The rotation of the second member is set to alternately switch the tilt control gas cylinder between a free state and a locked state. The reclining chair according to Claim 1 or 2.

5. In the operating device, the wire is drawn out from the switching mechanism unit to the rear side. The reclining chair according to Claim 1 or 2.

6. The operating device includes a bracket to which the front end of the tilt control gas cylinder is fixed, and a cover that covers the bracket from below. The bracket is connected to a rib provided at the rear end of the base by a horizontally long pin, and the pin is held immovable in the left-right direction by the cover. The reclining chair according to Claim 3.

7. The bracket has a structure in which an upper bracket through which the pin is inserted and a lower bracket to which the tilting control gas cylinder is fixed are overlapped, and the first operating member, the second operating member, and the spring are arranged in a space surrounded by the upper bracket and the lower bracket. The reclining chair according to claim 6.

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