JP2013000445A - Chair - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chair for obtaining a normal posture, a straight backward reclining posture, and a horizontally backward reclining posture without employing a complicated rocking mechanism and without being much influenced by the weight of a sitting person.SOLUTION: The chair 1 includes a leg body 2, right and left frame parts supported by the leg body 2, and a seat 4 positioned at the right and left frame parts. The right and left frames 3A, 3B are pivotally supported by the leg body 2 so as to allow a balancing motion to take place around a single axis core 20 extending in a horizontal direction. The seat 4 is configured to permit mutually different balancing motions of the right and left frames 3A, 3B. The chair includes a turning restriction mechanism 6 for restricting the balancing motions of the right and left frames 3A, 3B to be within a fixed range.

Description

  The present invention relates to a chair suitably used for school or office use.

  Conventionally, various types of chairs have been developed in which the seat is tilted backward in order to give a reclining feeling.

  However, the conventional one employs a complicated locking mechanism to cause the seat to tilt backward, and has a problem that the configuration is complicated and the number of parts increases. Further, such a locking mechanism is generally one that only tilts backward and rearward, and it is necessary to provide a more complicated mechanism if the left and right sinking amounts are made different (for example, (See Patent Document 1).

  Further, as a simple configuration, there is also known a configuration in which only the front portion of the seat is supported by a support, and the seat is tilted backward using elastic deformation of the seat or the support. In such a case, for example, each part of the chair has to be set so that the entire chair has rigidity so that it can withstand even when a heavy load is applied due to the seating of a heavy person. However, in such a case, there is a problem that a sufficient reclining feeling cannot be obtained when a light weight person is seated.

Japanese Patent No. 3891624

  The present invention has been made by paying attention to the above circumstances, and does not require a complicated locking mechanism, and is not affected by the weight of the seated person, so that the normal posture, right behind, and right and left rearward can be obtained. It is an object to provide a chair that can take a reclining posture.

  The present invention employs the following configuration in order to solve the above-described problems. That is, the chair according to the present invention comprises a leg, left and right frame parts supported by the leg, and seats positioned on the left and right frame parts. The frame portion is pivotally supported by the leg so that the balance can be moved around a single axial center extending in the left-right direction, and the seat allows different balance operations of the left and right frame portions. It is comprised so that it may be possible, It is provided with the rotation control mechanism which controls the balance operation | movement of the said right-and-left flame | frame part within a fixed range, It is characterized by the above-mentioned.

  Here, the “seat” refers to, for example, a plate-like material such as a shell in addition to a mesh-like stretched fabric between frames, a material that is easily bent by inserting slits or grooves in the shell, And the like provided with a cushioning material or the like.

  The “frame part” is a concept including a part formed mainly by a frame, a part formed integrally with other members such as a seat, and the like.

  The “balance operation” refers to an operation in which the seat is tilted backward and the rear end side is lowered and the front end side is raised while the load of the seated person is applied rearward around the axis.

  “To allow the balance operation” may be considered when a part or all of the seat is deformed or when the joint between the seat and the frame part is loose. As an example of the case where the coupling portion between the seat and the frame portion moves, there is one that slides.

  In this case, “front”, “rear”, “left”, and “right” mean “front”, “rear”, “left” as viewed from the seated person in a state where the seated person is seated on the chair according to the present invention. ”And“ right ”.

  If this is the case, there is no need to use a complicated locking mechanism, and when the seated person's load is applied to the rear, the seat tilts backward and the rear end side is lowered and the front end side is raised. Since the balance operation is performed separately on the left and right, the normal posture and the reclining posture to the right rear and the left and right rear can be taken without being significantly affected by the weight of the seated person.

  It is preferable that the left and right frame portions are provided with a return mechanism for rotating and biasing the left and right frame portions forward so that the left and right frame portions can independently rotate.

  As a specific example of the return mechanism, there is one provided with left and right resin springs having one end continuous with the front ends of the left and right frame portions and the other end supported by the legs.

  It is preferable that the right frame portion and the right resin spring, and the left frame portion and the left resin spring are integrally formed of synthetic resin, respectively.

  As a preferred example of the leg body, a leg blade, a leg column standing upright from the leg blade, and a support base that is supported on an upper end of the leg column and is rotatable around the axis of the leg column are provided. There are examples in which the left and right frame parts are supported on the support base so as to be able to perform a balance operation.

  As another preferred example of the leg, the leg includes a leg and a seat receiving portion provided on the leg, and the seat receiving portion has a pipe shape extending in the left-right direction. A frame portion is provided, and the axis of this frame portion is used as the axis for the balance operation.

  Here, the “pipe-shaped frame portion” may be any shape as long as the outer shape is a columnar shape, and may be a solid one having no hollow in addition to a hollow one. Good. Further, the frame portion is a concept including one formed mainly by the frame, one formed integrally with another member such as a leg, and the like.

  If it is such, since the flame | frame part which functions as a seat receiving part for balance operation can be utilized, while being able to reduce a number of parts, rigidity can also be improved.

  Since the present invention is configured as described above, it is not necessary to use a complicated locking mechanism, and the normal posture and the reclining posture to the rear and right and left rear are taken without being significantly affected by the weight of the seated person. You can provide a chair that can.

The whole perspective view showing the chair of a 1st embodiment of the present invention. The front view which shows the chair of the embodiment. XX sectional drawing in FIG. The right view which shows the chair of the embodiment. The YY sectional view taken on the line in FIG. Explanatory drawing which shows the rotation control mechanism of the embodiment. The whole perspective view which shows the chair of 2nd Embodiment of this invention. The front view which shows the chair of the embodiment. ZZ sectional drawing in FIG. The right view which shows the chair of the embodiment. The WW sectional view taken on the line in FIG. The whole perspective view which shows the chair of 3rd Embodiment of this invention. The front view which shows the chair of the embodiment. The bottom view which shows the chair of the embodiment. The right view which shows the chair of the embodiment. AA line sectional view in FIG. The whole perspective view showing the chair of a 4th embodiment of the present invention. The front view which shows the chair of the embodiment. The rear view which shows the chair of the embodiment. The bottom view which shows the chair of the embodiment. The right view which shows the chair of the embodiment. BB sectional drawing in FIG. The bottom view which abbreviate | omits and shows the chair of 5th Embodiment of this invention. CC sectional view taken on the line in FIG. The right view which shows the chair of the modification of this invention.

<First Embodiment>
First, a first embodiment of the present invention will be described with reference to FIGS.

  In this embodiment, the present invention is applied to an office swivel chair. As shown in FIGS. 1 to 5, the chair 1 includes a leg 2, left and right frames 3 A and 3 B supported by the leg 2, and a seat 4 positioned on the left and right frames 3 A and 3 B. The back 5 is supported by the left and right frames 3A and 3B which also serve as the seat frame of the seat 4. The left and right frame portions of the present invention are mainly composed of left and right frames 3A and 3B.

  As shown in FIGS. 1 to 5, the leg body 2 is supported by a leg blade 21 having a caster attached to the tip, a leg column 22 standing from the leg blade 21, and an upper end of the leg column 22. A support base 23 that can pivot about the axis of the leg support 22 is provided, and the left and right frames 3A and 3B are supported on the support base 23 so as to be able to perform a balance operation. The leg support 22 is constituted by a gas spring, and the support base 23 is fixed to the upper end of the cylinder shaft 24 of the gas spring. The support base 23 includes a support base body 25 fixed to the cylinder shaft 24 and arms 26 erected upward from both left and right ends of the support base body 25. It can turn in the horizontal direction. Left and right support shafts 27 are provided at the upper ends of the left and right arms 26 so that the shaft centers 20 coincide with each other, and the left and right frames 3A and 3B are supported on the support shafts 27 so that the balance operation is possible. Yes. Here, the “balance operation” refers to an operation about the support shaft 27 as a center, when the seated person's load is applied to the rear, the seat 4 tilts backward, the rear end side lowers, and the front end side rises. In this embodiment, this balance operation is an operation in which the seat 4 returns to the initial state (f) when the load of the seated person is applied forward, with the support shaft 27 as the center, and the front end side is lowered and the rear end side is raised. Also included. The shaft center 20 extends in the left-right direction of the chair 1.

  As shown in FIGS. 1 to 5, the left and right frames 3 </ b> A and 3 </ b> B are pivotally supported by the leg 2 so as to be able to perform a balance operation around the single axis 20 extending in the left-right direction. For example, it is made of a synthetic resin reinforced with fibers. These left and right frames 3A and 3B are each provided with a frame main body 3A1 and 3B1, and fixed arms 3A2 and 3B2 extending downward from the center of the frame main bodies 3A1 and 3B1, respectively. The fixed arms 3A2 and 3B2 are integrally formed.

  As shown in FIGS. 1 to 5, the seat 4 has a mesh-like stretch fabric 41 stretched between the left and right frames 3 </ b> A and 3 </ b> B that also serve as a seat frame. The seat 4 includes a front region 8 in front of the axis 20 and a rear region 9 in the rear of the axis 20.

  As shown in FIGS. 1 to 5, the backrest 5 is obtained by stretching a mesh-like stretch fabric 51 between the left and right back frames 5A and 5B formed integrally with the left and right frames 3A and 3B. The left and right frames 3A and 3B and the left and right back frames 5A and 5B are integrally formed of, for example, synthetic resin reinforced with fibers. The left and right back frames 5A and 5B are connected by a horizontal member 52. The horizontal member 52 has elasticity that allows the left and right back frames 5A, 5B to tilt at different angles. The chair 1 according to this embodiment is configured such that the backrest 5 and the seat 4 are interlocked. Specifically, the seat 4 is tilted in accordance with the backward tilting operation of the backrest 5 while the front side is raised. It is a weight-sensing type that can be moved.

  The chair 1 also includes a rotation restricting mechanism 6 that restricts the balance operation of the left and right frames 3A and 3B within a certain range. As shown in FIG. 6, the rotation restricting mechanism 6 includes a long hole-shaped recess 61 provided in the arm 26 of the support base 23 and the recesses provided in the fixed arms 3A2, 3B2 of the left and right frames 3A, 3B. 61 in the initial state (f) before the rear end side of the seat 4 sinks, the protrusion 62 is locked to the one end 63 side of the recess 61, In the subsidence state (s) in which the rear end side of the seat 4 is most depressed, the protrusion 62 is locked to the other end 64 side of the recess 61. In FIG. 4, the initial state (f) is indicated by a solid line, and the subsidence state (s) is indicated by a two-dot chain line.

  Further, as shown in FIGS. 1 to 5, the chair 1 rotates the left and right frames 3A and 3B forward so that the left and right frames 3A and 3B can rotate independently. A return mechanism 7 for energizing is provided. The return mechanism 7 includes left and right resin springs 7A and 7B in which one ends 7A1 and 7B1 are connected to the front ends of the left and right frames 3A and 3B, and the other ends 7A2 and 7B2 are supported by the legs 2. is there. The right frame 3A and the right resin spring 7A, and the left frame 3B and the left resin spring 7B are each integrally formed of synthetic resin. The resin springs 7A and 7B are belt-shaped in this embodiment, have an overall shape and a cross-sectional shape that are easily elastically deformed, and the left and right frames 3A and 3B having rigidity perform a balance operation. In this case, it is deformed while accumulating repulsive force.

  In the case of such a chair 1, when sitting on the seat 4 in the office posture, the load caused by the weight of the seated person acts on the front region 8 of the seat 4, so that the left and right frames 3 </ b> A and 3 </ b> B tilt. Instead, the seat 4 is supported in a stable state. In addition, when the seated person leans on the backrest 5 and the load is transferred to the rear region 9 of the seat 4, the left and right frames 3A and 3B operate as a balance, and the rear region 9 of the seat 4 sinks. .

  If the reclining operation is performed while the seated person is tilted to the right, the right frame 3A performs a greater balance operation than the left frame 3B, and the amount of sinking on the right side of the rear region 9 of the seat 4 is on the left side. Larger than the amount of subsidence. Similarly, if the reclining operation is performed in a state where the seated person is tilted to the left, the left frame 3B performs a balance operation more greatly than the right frame 3A, and the left side of the rear region 9 of the seat 4 sinks. The amount is greater than the amount of sinking on the right side. When the seat occupant moves the load to the front region 8 of the seat 4 and returns to the working posture, the left and right frames 3A and 3B perform the balance operation forward, and the rear region 9 of the seat 4 is in an initial state before sinking. Self-return to (f).

  Thus, the chair 1 of this embodiment includes the leg 2, the left and right frames 3A and 3B supported by the leg 2, and the seat 4 positioned on the left and right frames 3A and 3B. The left and right frames 3A and 3B are pivotally supported by the leg 2 so as to be able to perform a balance operation around a single axis 20 extending in the left-right direction. The left and right frames 3A and 3B are configured so as to allow different balance operations, and the rotation restricting mechanism 6 restricts the balance operations of the left and right frames 3A and 3B within a certain range. Therefore, it is not necessary to use a complicated locking mechanism, and a suitable reclining feeling can be obtained with a simple structure. In addition, the rotation support portion for the balance operation is in the center portion in the front-rear direction of the seat 4, and the center of gravity of the load by the seated person is concentrated on the front region 8 during the work posture, so that the work posture can be stably maintained and rest Since the center of gravity of the load by the seated person concentrates on the rear region 9 in the posture, the rear region 9 of the seat 4 falls downward, so that a suitable reclining posture can be taken. That is, the chair 1 has a structure like a seesaw in which the front side is raised when the rear side of the seat 4 is lowered, and the front side of the seat 4 is lowered and returned to the original position. It can be said that.

  In particular, the chair 1 according to the present embodiment is provided with the back frames 5A and 5B in succession to the left and right frames 3A and 3B that also serve as seat frames, so that the seat 4 and the backrest 5 are caused to perform a series of tilting operations. Can do. That is, when the seated person takes a reclining posture, the rear region 9 of the seat 4, which is a region on the rear side of the axis 20, is elastically deformed and sinks downward. The backrest 5 also tilts backward. The rear region 9 of the seat 4 of the present embodiment is assumed to deform the entire left and right frames 3A and 3B that also serve as a seat frame, but is not limited to this. For example, the frame is rigid and does not deform, Another return mechanism for elastically deforming the seat may be provided, and the seat may be elastically deformed by the action of the return mechanism.

  Such a movement is performed without being significantly affected by the weight of the seated person. Conventionally, when the stability of the seat 4 in the working posture is obtained, the seat 4 is firmly supported by the leg body 2 and there is a problem that it is difficult to take a reclining posture. For example, if the rear side of the seat 4 is lowered, the front side is raised, and conversely, the front side is lowered, and when the seat 4 is returned to the original position, the rear side is raised and returned to the original position. Without, it is possible to stably exhibit a suitable reclining feeling right behind and right and left rear.

  Further, when returning to the working posture again, the center of gravity of the load of the seated person moves to the front region 8 of the seat 4, so that it can be naturally shifted to the working posture by the balance operation. That is, in this case as well, the seat occupant can move the weight from the normal posture to the reclining posture from the normal posture to the back and left and right backwards and the weight movement in the opposite direction without being greatly affected by the weight of the seat occupant. The seating surface naturally follows the posture change. Therefore, a feeling that the inclination of the seat 4 can be changed at the will of the seated person is obtained.

  Furthermore, since the chair 1 of this embodiment is provided with the rotation control mechanism 6, even if the seat 4 is supported so as to rotate around the single axis 20, the rearward is unlimited. The fall is regulated and the seated person can take a reclining posture with peace of mind.

  In addition, the chair 1 has a backrest 5 and a seat 4 on the opposite side, and a backrest 5 and a seat on the opposite side when the seated person leans to the backrest 5 or to the left or right of the seat 4. A tilting motion larger than 4 is performed to sink downward. That is, the seat surface and the backrest surface are twisted by tilting left and right, and the frames 3A and 3B and the back frames 5A and 5B can be tilted rearward independently on the left and right. Therefore, the seat 4 and the backrest 5 can easily follow the tilting motion of the seated person to the rear left and right. In other words, since the left and right frames 3A and 3B can perform a balance operation at different angles, it is possible to easily perform a sinking operation in the front-rear direction while tilting in the left-right direction. In particular, since the chair 1 performs a balance operation around the central portion of the seat 4 in the front-rear direction, the amount of sinking of the rear end portion of the rear region 9 of the seat 4 can be increased.

  The chair 1 includes a return mechanism 7 that pivots the left and right frames 3A and 3B forward so that the left and right frames 3A and 3B can independently rotate. The backward inclination of the seat 4 can be restricted to a certain amount. In particular, in this embodiment, the return mechanism 7 has one end 7A1, 7B1 continuous with the front end of the left and right frames 3A, 3B, and the other end 7A2, 7B2 supported on the leg 2 with the left and right resin springs 7A. 7B, the return mechanism 7 is disposed on the lower surface side of the seat 4 and the overall appearance of the chair 1 can be improved.

  Further, since the right frame 3A and the right resin spring 7A, and the left frame 3B and the left resin spring 7B are each integrally formed of synthetic resin, the number of parts and man-hours can be reduced. In addition to achieving this, it is possible to maintain strength. That is, by integrally molding the left and right frames 3A and 3B and the left and right resin springs 7A and 7B with the same material, it is possible to realize a structure that is inexpensive and easy to assemble. The resin springs 7A and 7B also serve as positioning mechanisms for determining the positions of the backrest 5 and the seat 4 in a no-load state where no load is applied to the seating surface.

  Also, the left and right frames 3A and 3B, which also serve as seat frames, and the left and right back frames 5A and 5B are made of synthetic resin, and the left and right frames 3A and 3B and the left and right back frames 5A and 5B themselves are elastically deformed. Depending on how the seated person applies the load, it can be tilted back and forth and tilted backward.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIGS.

  In this embodiment, the present invention is applied to an office swivel chair. As shown in FIGS. 7 to 11, the chair 1 includes a leg body 2, left and right frames 3A and 3B supported by the leg body 2, and a seat 4 positioned on the left and right frames 3A and 3B. And a backrest 5 having left and right back frames 5A and 5B supported by the left and right frames 3A and 3B.

  As shown in FIGS. 7 to 11, the leg body 2 is supported by a leg blade 21 having a caster attached to the tip, a leg column 22 standing from the leg blade 21, and an upper end of the leg column 22. A support base 23 that can pivot about the axis of the leg support 22 is provided, and the left and right frames 3A and 3B are supported on the support base 23 so as to be able to perform a balance operation. The leg support 22 is constituted by a gas spring, and the support base 23 is fixed to the upper end of the cylinder shaft 24 of the gas spring. The support base 23 includes a support base body 25 fixed to the cylinder shaft 24 and arms 26 erected upward from both left and right ends of the support base body 25. It can turn in the horizontal direction. Left and right support shafts 27 are provided at the upper ends of the left and right arms 26 so that the shaft centers 20 coincide with each other, and the left and right frames 3A and 3B are supported on the support shafts 27 so that the balance operation is possible. Yes. Here, the “balance operation” refers to an operation about the support shaft 27 as a center, when the seated person's load is applied to the rear, the seat 4 tilts backward, the rear end side lowers, and the front end side rises. In the present embodiment, the balance operation includes an operation in which the seat 4 returns to the initial state when the seated person's load is applied forward and the front end side is lowered and the rear end side is raised with the support shaft 27 as the center. Yes. The shaft center 20 extends in the left-right direction of the chair 1.

  As shown in FIGS. 7 to 11, the left and right frames 3A and 3B are pivotally supported by the leg 2 so as to be able to perform a balance operation around the single axis 20 extending in the left-right direction. For example, it is made of a synthetic resin reinforced with fibers. These left and right frames 3A and 3B are each provided with a frame main body 3A1 and 3B1, and fixed arms 3A2 and 3B2 extending downward from the center of the frame main bodies 3A1 and 3B1, respectively. The fixed arms 3A2 and 3B2 are integrally formed.

  As shown in FIGS. 7 to 11, the seat 4 includes a seat shell 42 formed of synthetic resin or the like, a cushion 43 provided on the seat shell 42, and a tension fabric 41 that covers the cushion 43. And is mounted on the left and right frames 3A and 3B. Note that this attachment has a structure that allows the left and right frames 3A and 3B to allow a balance operation at different angles, and an appropriate method such as slide coupling or elastic coupling is used.

  As shown in FIGS. 7 to 11, the backrest 5 includes left and right back frames 5A and 5B formed integrally with the left and right frames 3A and 3B, and back shells attached to the left and right back frames 5A and 5B. 53. The back shell 53 is attached to the front side of the left and right back frames 5A, 5B. Note that this attachment has a structure that allows the left and right back frames 5A and 5B to tilt at different angles, and an appropriate method such as slide coupling or elastic coupling is used. Further, the left and right frames 3A and 3B and the left and right back frames 5A and 5B are integrally formed of, for example, synthetic resin reinforced with fibers. The left and right back frames 5A and 5B are connected by a horizontal member 52. The horizontal member 52 has elasticity that allows the left and right back frames 5A, 5B to tilt at different angles. The chair 1 according to this embodiment is configured such that the backrest 5 and the seat 4 are interlocked. Specifically, the seat 4 is tilted in accordance with the backward tilting operation of the backrest 5 while the front side is raised. It is a weight-sensing type that can be moved.

  The chair 1 includes a rotation restricting mechanism that restricts the balance operation of the left and right frames 3A and 3B within a certain range. This rotation restricting mechanism has a configuration according to the rotation restricting mechanism 6 of the first embodiment, and a description thereof will be omitted. In FIG. 10, the initial state (f) is indicated by a solid line, and the subsidence state (s) is indicated by a two-dot chain line.

  Further, as shown in FIGS. 7 to 11, the chair 1 rotates the left and right frames 3A and 3B forward so that the left and right frames 3A and 3B can independently rotate. A return mechanism 7 for energizing is provided. The return mechanism 7 includes left and right resin springs 7A and 7B in which one ends 7A1 and 7B1 are connected to the vicinity of the rear ends of the left and right frames 3A and 3B and the other ends 7A2 and 7B2 are supported by the leg body 2. Is. The resin springs 7A and 7B are belt-shaped in this embodiment, have an overall shape and a cross-sectional shape that are easily elastically deformed, and the left and right frames 3A and 3B having rigidity perform a balance operation. In this case, it is deformed while accumulating repulsive force.

  In the case of such a chair 1, when sitting on the seat 4 in the office posture, the load caused by the weight of the seated person acts on the front region 8 of the seat 4, so that the left and right frames 3 </ b> A and 3 </ b> B tilt. Instead, the seat 4 is supported in a stable state. In addition, when the seated person leans on the backrest 5 and the load is transferred to the rear region 9 of the seat 4, the left and right frames 3A and 3B operate as a balance, and the rear region 9 of the seat 4 sinks. .

  If the reclining operation is performed while the seated person is tilted to the right, the right frame 3A performs a greater balance operation than the left frame 3B, and the amount of sinking on the right side of the rear region 9 of the seat 4 is on the left side. Larger than the amount of subsidence. Similarly, if the reclining operation is performed in a state where the seated person is tilted to the left, the left frame 3B performs a balance operation more greatly than the right frame 3A, and the left side of the rear region 9 of the seat 4 sinks. The amount is greater than the amount of sinking on the right side. When the seat occupant moves the load to the front region 8 of the seat 4 and returns to the working posture, the left and right frames 3A and 3B perform the balance operation forward, and the rear region 9 of the seat 4 is in an initial state before sinking. Self-return to (f).

  As described above, the seat 4 is not limited to the seat surface shown in the first embodiment formed of a mesh material, and the seat surface is formed of the cushion 43 or the like as shown in the present embodiment. May be. Instead of allowing the mounting portion to move freely, the seat shell may be elastically deformed in the twisting direction, or a seat shell may be provided with a slit, a groove or the like to be easily torsionally deformed.

  If it is such, the effect according to 1st Embodiment is acquired.

  Further, in the case of this embodiment, if the seat 4 is twisted in the left-right direction, the restoring force for returning the seat 4 to the initial state (s) is only the elastic deformation force of the left and right frames 3A, 3B. The seat shell 42 can also be shared. As described above, since the restoring force for the seat 4 can be shared by a plurality of members, each member, that is, the left and right frames 3A and 3B and the seat shell 42 each have a small elastic restoring force. As a whole, the weight can be reduced. Further, the seat 4 provided with the seat shell 42 is easier to assemble and easier to handle at the time of the attachment work than the one in which a stretch fabric is stretched between the left and right seat frames.

  In addition, the chair 1 performs a balance operation in accordance with the movement of the load of the seated person that the front side rises when the rear side of the seat 4 is lowered. When the front end of the seat 4 is raised, the leg of the seated person is lifted and is seated. If the cushion 43 is arranged on the seat shell 42 as in the present embodiment, the front side of the cushion 4 is the load of the seated person when the front end of the seat 4 is raised. Is elastically deformed in the thickness direction. Therefore, it is possible to reduce the degree of rising of the seating surface at the front end of the seat 4, and it is possible to suppress the problem of seating feeling such as the lifting of the foot as described above.

  The return mechanism 7 of the present embodiment has one end 7A1, 7B1 attached to the vicinity of the rear end of the left and right frames 3A, 3B, and the other end 7A2, 7B2 supported on the upper surface of the support base 23 of the leg body 2. Since the left and right resin springs 7A and 7B are provided, the return mechanism 7 is disposed on the lower surface side of the seat 4, and the aesthetic appearance of the chair 1 as a whole can be improved. Further, since the left and right resin springs 7A and 7B extend from the left and right rear ends of the seat 4 toward the center of the seat 4, the seat occupant tilts to the backrest 5 or to the left or right of the seat 4. From the drowned subsidence state (s) to the original initial state (f) that does not tilt in either the front-rear direction or the left-right direction, the rear region 9 of the seat 4 is easily returned by the repulsive force of the resin springs 7A and 7B. Can be made.

<Third Embodiment>
Next, a third embodiment of the present invention will be described with reference to FIGS.

  In this embodiment, the present invention is applied to a so-called cantilever type pipe chair. As shown in FIGS. 12 to 16, the chair 1 includes a leg body 2, left and right frames 3A and 3B supported by the leg body 2, and a seat 4 positioned on the left and right frames 3A and 3B. And a backrest 5 supported by the left and right frames 3A and 3B.

  As shown in FIGS. 12 to 16, the leg body 2 includes a front leg 82 and a rear leg 83, and a seat receiving portion 84 provided on the legs 82 and 83, and the seat receiving portion 84. Is provided with an intermediate frame 86 that is a pipe-shaped frame portion extending in the left-right direction, and the axis of the intermediate frame 86 is used as the axis 20 for the balance operation. More specifically, the leg 2 includes a left and right base 81, left and right front legs 82 erected from the front end of the base 81, left and right rear legs 83 erected from the rear end of the base, and left and right A rear frame 87 disposed between the upper ends of the rear legs 83 and a seat receiving portion 84 extending rearward from the upper ends of the front legs 82 are provided. The seat receiving portion 84 includes left and right upper frames 88 that extend horizontally from the upper ends of the left and right front legs 82 to the center position in the front-rear direction of the seat 4, a front frame 86 that connects the vicinity of an intermediate position between the upper frames 88, An intermediate frame 86 for connecting the rear ends of the upper frame 88 is provided. In other words, the seat receiving portion 84 is a front portion mainly composed of the upper frame 88 and the front frame 86 that extend substantially horizontally from the upper ends of the left and right front legs 82 toward the center in the front-rear direction of the seat 4. 91 and an intermediate portion 92 mainly composed of the intermediate frame 86 extending substantially horizontally from the rear end of the front portion 91 toward the center of the seat 4. In this embodiment, the left and right bases 81, the front legs 82, the rear legs 83, the rear frame 87, the upper frame 88 and the intermediate frame 86 are made by bending one pipe. The left and right frames 3A and 3B are pivotally supported by a middle frame 86 having an axial center 20 extending in the left-right direction so that the balance operation is possible. Here, the “balance operation” refers to an operation in which the seat 4 tilts backward and the rear end side is lowered and the front end side is raised when the load of the seated person is applied to the rear with the intermediate frame 86 as the center. In this embodiment, this balance operation is an operation in which the seat 4 returns to the initial state (f) when the load of the seated person is applied forward, with the support shaft 27 as the center, and the front end side is lowered and the rear end side is raised. Also included. The shaft center 20 extends in the left-right direction of the chair 1.

  As shown in FIGS. 12 to 16, the left and right frames 3A and 3B are pivotally supported by the leg 2 so as to be able to perform a balance operation around the single axis 20 extending in the left-right direction. For example, it is made of a synthetic resin reinforced with fibers. Each of the left and right frames 3A and 3B includes a frame main body 3A1 and 3B1, and fixed arms 3A2 and 3B2 extending downward from the center of the frame main bodies 3A1 and 3B1. The fixed arm fixed arms 3A2 and 3B2 are attached to the frame main bodies 3A1 and 3B1 by using appropriate fasteners or the like.

  As shown in FIGS. 12 to 16, the seat 4 has a mesh-like stretch fabric 41 stretched between the left and right frames 3 </ b> A and 3 </ b> B that also serve as a seat frame. The seat 4 includes a front region 8 in front of the axis 20 and a rear region 9 in the rear of the axis 20.

  As shown in FIGS. 12 to 16, the backrest 5 is formed by stretching a mesh-like stretch fabric 51 between the left and right back frames 5A and 5B formed integrally with the left and right frames 3A and 3B. The left and right frames 3A and 3B and the left and right back frames 5A and 5B are integrally formed of, for example, synthetic resin reinforced with fibers. The left and right back frames 5A and 5B are connected by a horizontal member 52. The horizontal member 52 has elasticity that allows the left and right back frames 5A, 5B to tilt at different angles. The chair 1 according to this embodiment is configured such that the backrest 5 and the seat 4 are interlocked. Specifically, the seat 4 is tilted in accordance with the backward tilting operation of the backrest 5 while the front side is raised. It is a weight-sensing type that can be moved.

  The chair 1 includes a rotation restricting mechanism that restricts the balance operation of the left and right frames 3A and 3B within a certain range. This rotation restricting mechanism has a configuration according to the rotation restricting mechanism 6 of the first embodiment, and illustration and description thereof are omitted. 15 and 16, the initial state (f) is indicated by a solid line, and the subsidence state (s) is indicated by a two-dot chain line.

  Further, as shown in FIGS. 12 to 16, the chair 1 rotates the left and right frames 3A and 3B forward so that the left and right frames 3A and 3B can rotate independently. A return mechanism 7 for energizing is provided. The return mechanism 7 includes left and right resin springs 7A and 7B having one end 7A1 and 7B1 connected to the front end of the left and right frames 3A and 3B and the other end 7A2 and 7B2 supported by the rear frame 87 of the leg body 2. It is provided. The right frame 3A and the right resin spring 7A, and the left frame 3B and the left resin spring 7B are each integrally formed of synthetic resin. The resin springs 7A and 7B are belt-shaped in this embodiment, have an overall shape and a cross-sectional shape that are easily elastically deformed, and the left and right frames 3A and 3B having rigidity perform a balance operation. In this case, it is deformed while accumulating repulsive force.

  In the case of such a chair 1, when sitting on the seat 4 in the office posture, the load caused by the weight of the seated person acts on the front region 8 of the seat 4, so that the left and right frames 3 </ b> A and 3 </ b> B tilt. Instead, the seat 4 is supported in a stable state. In addition, when the seated person leans on the backrest 5 and the load is transferred to the rear region 9 of the seat 4, the left and right frames 3A and 3B operate as a balance, and the rear region 9 of the seat 4 sinks. .

  If the reclining operation is performed while the seated person is tilted to the right, the right frame 3A performs a greater balance operation than the left frame 3B, and the amount of sinking on the right side of the rear region 9 of the seat 4 is on the left side. Larger than the amount of subsidence. Similarly, if the reclining operation is performed in a state where the seated person is tilted to the left, the left frame 3B performs a balance operation more greatly than the right frame 3A, and the left side of the rear region 9 of the seat 4 sinks. The amount is greater than the amount of sinking on the right side. When the seat occupant moves the load to the front region 8 of the seat 4 and returns to the working posture, the left and right frames 3A and 3B perform the balance operation forward, and the rear region 9 of the seat 4 is in an initial state before sinking. Self-return to (f).

  If it is such, the effect according to 1st Embodiment is acquired.

  Furthermore, the chair 1 of the present embodiment performs a balance operation in accordance with the movement of the load of the seated person that the front side rises when the rear side of the seat 4 is lowered. However, the balance operation is performed around the intermediate frame 86. Can do. That is, the present invention can be realized without preparing a special member for performing a balance operation, and the number of parts can be reduced. The intermediate frame 86 is formed integrally with the base 81, the front and rear legs 82 and 83, the rear frame 87, and the upper frame 88, and thus has rigidity. Since it is continuous, the rigidity can be further increased.

  In the present embodiment, the seat 4 is supported by the intermediate frame 86, and the front frame 85 is in contact with the lower surface of the seat 4 in the initial state (f) to directly support the seat 4 in the left-right direction. Therefore, the front frame 85 serves as a stopper in the forward direction. That is, when the rear region 9 of the seat 4 returns to the initial state (f), the seat 4 does not tilt forward beyond the substantially horizontal initial state (f). In addition, the seat surface corresponding to the area surrounded by the intermediate frame 86, the front frame 85, and the upper frame 88 existing between the frames 86 and 85 has the seat 2 in the front-rear direction even when receiving a load. Therefore, it is possible to obtain an effect that a seated person can stably sit on the front region 8 of the seat 4 in the office posture.

<Fourth embodiment>
Next, a fourth embodiment of the present invention will be described with reference to FIGS.

  In this embodiment, the present invention is applied to a so-called four-leg pipe chair. As shown in FIGS. 17 to 22, the chair 1 includes a leg body 2, left and right frames 3A and 3B supported by the leg body 2, and a seat 4 positioned on the left and right frames 3A and 3B. And a backrest 5 supported by the left and right frames 3A and 3B.

  As shown in FIGS. 17 to 22, the leg body 2 includes a front leg 82 and a rear leg 83, and a seat receiving portion 84 provided on the legs 82 and 83, and the seat receiving portion 84. Is provided with an intermediate frame 86 that is a pipe-shaped frame portion extending in the left-right direction, and the axis of the intermediate frame 86 is used as the axis 20 for the balance operation. More specifically, the leg body 2 includes a pair of left and right front legs 82, a pair of left and right rear legs 83, a rear frame 87 disposed between the left and right rear legs 83, and the front legs 82. And a seat receiving portion 84 that extends rearward from the upper end.

  The seat receiving portion 84 includes left and right upper frames 88 that extend horizontally from the upper ends of the left and right front legs 82 to the center position in the front-rear direction of the seat 4, a front frame 86 that connects the vicinity of an intermediate position between the upper frames 88, An intermediate frame 86 that connects between the rear ends of the upper frame 88, a connection frame 89 that is provided adjacent to the intermediate frame 86 and extends in the left-right direction, both left and right ends of the connection frame 89, and the rear legs 83 An inclined frame 80 connected to the upper end and extending rearward while being gradually separated from the lower surface of the seat 2 is provided. In other words, the seat receiving portion 84 is a front portion mainly composed of the upper frame 88 and the front frame 86 that extend substantially horizontally from the upper ends of the left and right front legs 82 toward the center in the front-rear direction of the seat 4. 91, an intermediate portion 92 mainly composed of the intermediate frame 86 extending substantially horizontally from the rear end of the front portion 91 toward the center of the seat 4, and the intermediate portion while being gradually separated from the lower surface of the seat 2 92 is provided with a rear portion 93 mainly composed of the inclined frame 80 and the connection frame 89 extending rearward from the rear end of 92. In this embodiment, the front leg 82, the upper frame 88, and the intermediate frame 86 are made by bending one pipe. The rear legs 83, the rear frame 87, the inclined frame 80, and the connection frame 89 are made by bending one pipe. The left and right frames 3A and 3B are pivotally supported by a middle frame 86 having an axial center 20 extending in the left-right direction so that the balance operation is possible. Here, the “balance operation” refers to an operation in which the seat 4 tilts backward and the rear end side is lowered and the front end side is raised when the load of the seated person is applied to the rear with the intermediate frame 86 as the center. In this embodiment, this balance operation is an operation in which the seat 4 returns to the initial state (f) when the load of the seated person is applied forward, with the support shaft 27 as the center, and the front end side is lowered and the rear end side is raised. Also included. The shaft center 20 extends in the left-right direction of the chair 1.

  As shown in FIGS. 17 to 22, the left and right frames 3A and 3B are pivotally supported by the leg 2 so as to be able to perform a balance operation around the single axis 20 extending in the left-right direction. For example, it is made of a synthetic resin reinforced with fibers. Each of the left and right frames 3A and 3B includes a frame main body 3A1 and 3B1, and fixed arms 3A2 and 3B2 extending downward from the center of the frame main bodies 3A1 and 3B1. The fixed arm fixed arms 3A2 and 3B2 are provided with mounting portions 3A3 and 3B3 for mounting on the frame main bodies 3A1 and 3B1, and are mounted using appropriate fastening tools or the like.

  As shown in FIGS. 17 to 22, the seat 4 has a mesh-like tension fabric 41 stretched between the left and right frames 3 </ b> A and 3 </ b> B that also serve as a seat frame. The seat 4 includes a front region 8 in front of the axis 20 and a rear region 9 in the rear of the axis 20.

  As shown in FIGS. 17 to 22, the backrest 5 is obtained by stretching a mesh-like stretch fabric 51 between the left and right back frames 5A and 5B integrally formed with the left and right frames 3A and 3B. The left and right frames 3A and 3B and the left and right back frames 5A and 5B are integrally formed of, for example, synthetic resin reinforced with fibers. The left and right back frames 5A and 5B are connected by a horizontal member 52. The horizontal member 52 has elasticity that allows the left and right back frames 5A, 5B to tilt at different angles. The chair 1 according to this embodiment is configured such that the backrest 5 and the seat 4 are interlocked. Specifically, the seat 4 is tilted in accordance with the backward tilting operation of the backrest 5 while the front side is raised. It is a weight-sensing type that can be moved.

  The chair 1 includes a rotation restricting mechanism that restricts the balance operation of the left and right frames 3A and 3B within a certain range. This rotation restricting mechanism has a configuration according to the rotation restricting mechanism 6 of the first embodiment, and illustration and description thereof are omitted. 21 and 22, the initial state (f) is indicated by a solid line and the subsidence state (s) is indicated by a two-dot chain line.

  Further, as shown in FIGS. 17 to 22, the chair 1 rotates the left and right frames 3A and 3B forward so that the left and right frames 3A and 3B can rotate independently. A return mechanism 7 for energizing is provided. The return mechanism 7 includes left and right resin springs 7A and 7B having one end 7A1 and 7B1 connected to the front end of the left and right frames 3A and 3B and the other end 7A2 and 7B2 supported by the rear frame 87 of the leg body 2. It is provided. The right frame 3A and the right resin spring 7A, and the left frame 3B and the left resin spring 7B are each integrally formed of synthetic resin. The resin springs 7A and 7B are belt-shaped in this embodiment, have an overall shape and a cross-sectional shape that are easily elastically deformed, and the left and right frames 3A and 3B having rigidity perform a balance operation. In this case, it is deformed while accumulating repulsive force.

  In the case of such a chair 1, when sitting on the seat 4 in the office posture, the load caused by the weight of the seated person acts on the front region 8 of the seat 4, so that the left and right frames 3 </ b> A and 3 </ b> B tilt. Instead, the seat 4 is supported in a stable state. In addition, when the seated person leans on the backrest 5 and the load is transferred to the rear region 9 of the seat 4, the left and right frames 3A and 3B operate as a balance, and the rear region 9 of the seat 4 sinks. .

  If the reclining operation is performed while the seated person is tilted to the right, the right frame 3A performs a greater balance operation than the left frame 3B, and the amount of sinking on the right side of the rear region 9 of the seat 4 is on the left side. Larger than the amount of subsidence. Similarly, if the reclining operation is performed in a state where the seated person is tilted to the left, the left frame 3B performs a balance operation more greatly than the right frame 3A, and the left side of the rear region 9 of the seat 4 sinks. The amount is greater than the amount of sinking on the right side. When the seat occupant moves the load to the front region 8 of the seat 4 and returns to the working posture, the left and right frames 3A and 3B perform the balance operation forward, and the rear region 9 of the seat 4 is in an initial state before sinking. Self-return to (f).

  If it is such, the effect according to 1st Embodiment is acquired.

  Further, as in the third embodiment, the chair 1 according to the present embodiment performs a balance operation in accordance with the movement of the load of the seated person such that when the rear side of the seat 4 is lowered, the front side is raised. The balance operation can be performed around the center. That is, the present invention can be realized without preparing a special member for performing a balance operation, and the number of parts can be reduced. The intermediate frame 86 is formed integrally with the base 81, the front and rear legs 82 and 83, the rear frame 87, and the upper frame 88, and thus has rigidity. Since it is continuous, the rigidity can be further increased.

  In the present embodiment, the seat 4 is supported by the intermediate frame 86, and the front frame 85 abuts against the lower surface of the seat 4 via the spacer 31 in the initial state (f) to support the seat 4. Therefore, the spacer 31 serves as a forward stopper. That is, when the rear region 9 of the seat 4 returns to the initial state (f), the seat 4 does not tilt forward beyond the substantially horizontal initial state (f). In addition, the seat surface corresponding to the area surrounded by the intermediate frame 86, the front frame 85, and the upper frame 88 existing between the frames 86 and 85 has the seat 2 in the front-rear direction even when receiving a load. Therefore, it is possible to obtain an effect that a seated person can stably sit on the front region 8 of the seat 4 in the office posture.

<Fifth Embodiment>
Next, a fifth embodiment of the present invention will be described with reference to FIGS.

  In this embodiment, the present invention is applied to an office swivel chair having a so-called four-bar link structure. As shown in FIGS. 23 and 24, the chair 1 includes a leg body 2, left and right frames 3A and 3B supported by the leg body 2, and a seat 4 positioned on the left and right frames 3A and 3B. And a backrest 5 supported by the left and right frames 3A and 3B.

  As shown in FIGS. 23 and 24, the leg body 2 is supported by a leg blade 21 with a caster attached to the tip, a leg column 22 erected from the leg blade 21, and an upper end of the leg column 22. A support base 23 that can pivot about the axis of the leg support 22 is provided, and the left and right frames 3A and 3B are supported on the support base 23 so as to be able to perform a balance operation. The leg support 22 is constituted by a gas spring, and the support base 23 is fixed to the upper end of the cylinder shaft 24 of the gas spring. The support base 23 can turn in the horizontal direction together with the cylinder shaft 24.

  As shown in FIGS. 23 and 24, the left and right frames 3A and 3B are pivotally supported on the leg 2 via front and rear link elements 31, 32, 33, and 34, and are reinforced with fibers, for example. Made of synthetic resin and the like.

  The right front link element 31 is disposed forward of the leg struts 22, and the right rear link element 32 is disposed rearward of the leg struts 22. More specifically, the front link element 31 has an upper end supported on the frame 3A via a support shaft 31a so as to be rotatable and a lower end supported on the support base 23 via a support shaft 31b. It is what is done. The rear link element 32 has an upper end supported by the frame 3A via a support shaft 32a so as to be able to rotate, and a lower end supported by the support base 23 via a support shaft 32b so as to be able to rotate. In the present embodiment, the front link element 31 is rotatable from an initial state inclined forward to an upright state standing substantially vertically, and in the initial state, the lower end is higher than the upper end. It is set to be located on the rear side. Similarly, the rear link element 32 is rotatable from an initial state inclined forward to a final state inclined backward through an upright state standing vertically, and in the initial state, the lower end thereof Is set to be located behind the upper end.

  On the other hand, the left front link element 33 is disposed forward of the leg struts 22, and the left rear link element 34 is disposed rearward of the leg struts 22. More specifically, the front link element 33 has an upper end supported on the frame 3B via a support shaft 33a so as to be rotatable and a lower end supported on the support base 23 via a support shaft 33b. It is what is done. The rear link element 34 has an upper end supported by the frame 3B via a support shaft 34a so as to be able to rotate, and a lower end supported by the support base 23 via a support shaft 34b so as to be able to rotate. In the present embodiment, the front link element 33 is rotatable between an initial state inclined forward and an upright state standing substantially vertically, and in the initial state, the lower end is higher than the upper end. It is set to be located on the rear side. Similarly, the rear link element 34 is rotatable from an initial state inclined forward to a final state inclined rearward through an upright state rising vertically, and the lower end of the link element 34 in the initial state. Is set to be located behind the upper end.

  In the present embodiment, the axes of the support shafts 31a and 33a of the front link elements 31 and 33 in the initial state are made to coincide with each other, and the axes of the support shafts 31b and 33b of the front link elements 31 and 33 are made to match. Further, the axes of the support shafts 32a and 34a of the rear link elements 32 and 34 are made to coincide with each other, and the axes of the support shafts 32b and 34b of the rear link elements 32 and 34 are made to match. The right link elements 31 and 32 and the left link elements 33 and 34 may move separately.

  As shown in FIGS. 23 and 24, the seat 4 has a mesh-like stretch fabric 41 stretched between the left and right frames 3A and 3B which also serve as a seat frame. The seat 4 includes a front region 8 on the front side of the leg column 22 and a rear region 9 on the rear side of the leg column 20.

  As shown in FIGS. 23 and 24, the backrest 5 is obtained by stretching a mesh-like stretch fabric 51 between the left and right back frames 5A and 5B formed integrally with the left and right frames 3A and 3B. The left and right frames 3A and 3B and the left and right back frames 5A and 5B are integrally formed of, for example, synthetic resin reinforced with fibers. The chair 1 according to this embodiment is configured such that the backrest 5 and the seat 4 are interlocked. Specifically, the seat 4 is tilted in accordance with the backward tilting operation of the backrest 5 while the front side is raised. It is a weight-sensing type that can be moved.

  The chair 1 includes a rotation restricting mechanism that restricts the balance operation of the left and right frames 3A and 3B within a certain range. This rotation restricting mechanism has a configuration according to the rotation restricting mechanism 6 of the first embodiment, and illustration and description thereof are omitted. In FIG. 24, the initial state (f) is indicated by a solid line, and the subsidence state (s) is indicated by a two-dot chain line.

  Further, as shown in FIGS. 23 and 24, the chair 1 rotates the left and right frames 3A and 3B forward so that the left and right frames 3A and 3B can rotate independently. A return mechanism 7 for energizing is provided. The return mechanism 7 includes left and right resin springs 7A and 7B having one end 7A1 and 7B1 connected to the front end of the left and right frames 3A and 3B and the other end 7A2 and 7B2 supported by the rear frame 87 of the leg body 2. It is provided. The right frame 3A and the right resin spring 7A, and the left frame 3B and the left resin spring 7B are each integrally formed of synthetic resin. The resin springs 7A and 7B are belt-shaped in this embodiment, have an overall shape and a cross-sectional shape that are easily elastically deformed, and the left and right frames 3A and 3B having rigidity perform a balance operation. In this case, it is deformed while accumulating repulsive force.

  In the case of such a chair 1, when sitting on the seat 4 in the office posture, the load caused by the weight of the seated person acts on the front region 8 of the seat 4, so that the left and right frames 3 </ b> A and 3 </ b> B tilt. Instead, the seat 4 is supported in a stable state. In addition, when the seated person leans on the backrest 5 and the load is transferred to the rear region 9 of the seat 4, the left and right frames 3A and 3B operate as a balance, and the rear region 9 of the seat 4 sinks. .

  If the reclining operation is performed with the seated person tilted to the right, the right frame 3A will perform a larger locking operation than the left frame 3B, and the amount of subsidence on the right side of the rear region 9 of the seat 4 will be on the left side. Larger than the amount of subsidence. Similarly, if the reclining operation is performed with the seated person tilted to the left, the left frame 3B will perform a greater locking operation than the right frame 3A, and the left side sink of the rear region 9 of the seat 4 will occur. The amount is greater than the amount of sinking on the right side. When the seated person shifts the load to the front region 8 of the seat 4 and returns to the office posture, the left and right frames 3A and 3B are tilted forward, and the rear region 9 of the seat 4 is in an initial state before sinking (f). Self-return to.

  If it is such, the effect according to 1st Embodiment is acquired.

  In particular, in the present embodiment, the right link elements 31, 32 and the left link elements 33, 34 are supported so as to be independently tiltable, so that the seat 4 follows the torsional deformation in the left-right direction of the seated person. It becomes. In addition, since the front link elements 31 and 33 are inclined forward in the initial state, the front side of the seat 4 is lifted during the reclining posture. Therefore, even if the link elements 31, 32, 33, and 34 are provided, the left and right frames 3 </ b> A and 3 </ b> B can perform a balance operation on the leg 2. Here, the “balance operation” means that the seat 4 is tilted backward when the seated person's load is applied to the rear of the chair 1 with the imaginary axis extending in the left-right direction of the chair 1 as the rear end side. This is the movement of the front end side as it goes down. In the present embodiment, this balance operation involves the seat 4 returning to the initial state (f) when the load of the seated person is applied forward about the virtual axis extending in the left-right direction of the chair 1. This includes the operation of lowering the front end side and raising the rear end side.

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

  For example, as shown in FIG. 25, the seat 4 may be supported by the leg 2 via the protrusion 32. Hereafter, the same code | symbol is attached | subjected to the part same as the structure of the chair of 3rd Embodiment, and detailed description is abbreviate | omitted. The front frame 86 of the chair 1 connects the vicinity of the front end of the upper frame 88, that is, the vicinity of the upper end of the front leg 82. A protrusion 32 that abuts against the front frame 86 in the initial posture (f) is provided on the lower surface side of the seat 4. Specifically, the front portions 91 of the left and right frames 3A, 3B are each provided with a protrusion 32 that protrudes downward.

  If it is such, the forward inclination of the seat 4 can be controlled. That is, when the seated person moves the load to the front region 8 of the seat 4 and returns to the office posture, and the left and right frames 3A and 3B perform the balance operation forward, the front region 8 and the rear region of the seat 4 9 is controlling so that it can return to the initial state (f) before sinking appropriately. Therefore, it is possible to form a stable region that can be stably seated in the office posture.

  Further, if the front frame 86 is arranged at the position as in this modification, the resin springs 7A and 7B can be engaged with the lower surface of the front frame 86 during the reclining posture, thereby restricting the backward tilt of the seat 4. .

  The protrusions described above may be provided integrally with the frame, or may be formed as separate members attached to the frame. Further, the protrusion may be attached to the frame. Further, the protrusion may be elastically deformed or may not be elastically deformed, and the shape and material thereof are not particularly limited. Further, the mounting position of the front frame is not limited to the illustrated one, and it may be provided at an arbitrary position between the left and right upper frames or at an arbitrary position between the left and right front legs. Good.

  The shaft may be any shaft as long as it has a single axis and extends in the left-right direction, and is not limited to the shaft spaced apart from the left and right as in this embodiment. If they are separated from each other on the left and right, they can be formed integrally with the support base and the frame, so that the number of parts and man-hours can be reduced. On the other hand, if the shaft is continuous in the left-right direction, the load of the seated person can be shared by the shaft, so that the rigidity of the chair can be increased. That is, if the shafts are separated from each other in the left and right directions, the shaft is provided at the tip supported in a cantilevered manner, so that it is difficult to maintain the strength, but the support shaft is composed of one shaft that is continuous in the left and right direction. If so, the rigidity of the support shaft itself can be increased, and the shaft center can be stabilized on the left and right. In the above-described embodiment, the support shaft is formed integrally with the leg-side member. However, the support shaft is not limited to this, and for example, the support shaft is formed integrally with the frame-side member, or the support shaft is connected to the leg or the frame. May be configured separately.

  The rotation restricting mechanism is not limited to the one shown in the present embodiment, and various shapes and dimensions can be changed. Furthermore, a protrusion may be provided on the support base side and a recess may be provided on the frame side. Further, the concave portion is not limited to a bottomed hole shape, and may be a through hole shape, a gap provided between a plurality of spaced protrusions, or the like.

  The return mechanism may be any mechanism as long as the left and right frame parts operate independently. In addition to the resin spring described above, a metal coil spring or leaf spring is used. Also good. The return mechanism may be attached at any position on the front, center and rear of the seat. For example, even when the return mechanism is attached to the front portion of the seat, various changes such as adjusting the repulsive force by changing the position of one end of the resin spring shown in the first embodiment can be made. That is, even when the resin spring is formed in such a manner that one end is formed continuously with the front ends of the left and right frame portions, the front ends of the left and right frame portions are curved to the back side of the seat surface, The total distance between one end of the spring and the leg to which the other end of the resin spring is attached is set to be short, or conversely, the front ends of the left and right frame parts are located behind the front end of the seating surface, in other words, For example, the resin spring is bent to the front side of the seat surface by setting it at a location between the front end of the seat and the portion pivotally supported by the support shaft, and one end of the resin spring and the other end of the resin spring. It is also possible to set a long total distance from the leg to which is attached.

  Further, a receiving part for restricting the backward tilting operation of the seat to a certain amount may be provided at the lower portion of the seat by a method other than the resin spring or the rotation restricting mechanism. If it is such, it can prevent that a seat surface inclines more than necessary and can give a seated person a sense of security.

  In addition, various changes may be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Chair 2 ... Leg body 20 ... Axle 21 ... Leg blade 22 ... Leg support 23 ... Support base 3A, 3B ... Frame 4 ... Seat 6 ... Rotation restricting mechanism 7 ... Return mechanism 7A, 7B ... Resin spring 7A1, 7B1 ... one end 7A2, 7B2 ... the other end

Claims (6)

A chair comprising a leg, left and right frame parts supported by the leg, and a seat positioned on the left and right frame parts,
The left and right frame parts are pivotally supported by the legs so that they can each be scaled around a single axial center extending in the left-right direction, and the seat has a different balance between the left and right frame parts. A chair configured to allow movement and comprising a rotation restricting mechanism for restricting a balance operation of the left and right frame portions within a certain range. The chair according to claim 1, further comprising a return mechanism that pivots the left and right frame parts forward so that the left and right frame parts can independently rotate. The chair according to claim 2, wherein the return mechanism includes left and right resin springs having one end continuous with the front ends of the left and right frame portions and the other end supported by the legs. The chair according to claim 3, wherein the right frame portion and the right resin spring, and the left frame portion and the left resin spring are each integrally formed of a synthetic resin. The leg body is provided with leg blades, leg struts erected from the leg wings, and a support base that is supported on an upper end of the leg struts and can turn around an axis of the leg struts. The chair according to claim 1, 2, 3, or 4, wherein the left and right frame portions are supported by the support base so as to be able to perform a balance operation. The leg body includes a leg and a seat receiving portion provided on the leg, and the seat receiving portion includes a pipe-shaped frame portion extending in the left-right direction. The chair according to claim 1, 2, 3, or 4, wherein a heart is used as an axis for the balance operation.

Images