Exercise chair

Abstract

A chair includes a movable part including a seat on which a user sits, a supporting part configured to support the movable part in such a way that the movable part can be moved to the right and to the left; and a restoration unit, which is a biasing member configured to bias the movable part toward the neutral position in the right and the left. The supporting part supports the movable part in such a way that the movable part descends as the movable part is away from the neutral position.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from Japanese patent application No. 2021-107435, filed on Jun. 29, 2021, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND

The present disclosure relates to a chair that achieves a motion linkage between lower limbs and a trunk.

Patent Literature 1 (Japanese Unexamined Patent Application Publication No. 2018-126281) discloses a chair that swings a seat of a chair by an actuator. This chair is intended to enable a user who sits on the swinging chair to perform an exercise that simulates, for example, horseback riding.

SUMMARY

The configuration disclosed in Patent Literature 1 requires a high cost due to the use of, for example, the actuator for driving, for example, a seat and causes limitations in location and convenience for charging or the like.

An object of the present disclosure is to provide a chair that can be provided for a low cost, is highly convenient, and is capable of providing highly effective exercise.

According to a first aspect of the present disclosure, a chair including: a movable part including a seat on which a user sits; a supporting part configured to support the movable part in such a way that it can be moved to the right and to the left; and a biasing member configured to bias the movable part toward a neutral position in the right and the left, in which the supporting part supports the movable part in such a way that the movable part descends as the movable part is away from the neutral position is provided. According to the aforementioned configuration, a chair that can be provided for a low cost, is highly convenient, and is capable of providing highly effective exercise can be provided.

According to a second aspect of the present disclosure, a chair including: a movable part including a seat on which a user sits; a supporting part configured to support the movable part in such a way that it can be moved to the right and to the left; and a biasing member configured to bias the movable part toward a neutral position in the right and the left, in which the supporting part supports the movable part in such a way that the movable part is swung to the right and to the left about a roll axis extending backward and forward, and the roll axis is set to be lower than the movable part when the movable part is positioned at the neutral position is provided. According to the aforementioned configuration, a chair that can be provided for a low cost, is highly convenient, and is capable of providing highly effective exercise can be provided.

The supporting part may include a rail that defines a trajectory of the movement of the movable part in the right and the left, the rail may be inclined so as to descend toward an end part of the rail from the center of the rail in the longitudinal direction, and the movable part may move along the rail of the supporting part.

The rail may include a right rail part that is extended to the right from the center of the rail and a left rail part that is extended to the left from the center of the rail, and the movable part may include a right coupling part slidably coupled to the right rail part and a left coupling part slidably coupled to the left rail part.

The seat may be configured so as to be able to turn about a yaw axis.

The movable part may further include a movable part body interposed between the supporting part and the seat, and the seat may be mounted on the movable part body and configured so as to be able to turn about a yaw axis with respect to the movable part body.

The movable part may further include a movable part body interposed between the supporting part and the seat, and the seat may be mounted on the movable part body and configured so as to be able to turn about a yaw axis with respect to the supporting part.

The seat may be configured so that it can be tilted backward and forward with respect to the movable part body.

The seat may be configured so that it can be tilted to the right and to the left and backward and forward with respect to the movable part body.

The movable part may further include a universal joint configured to couple the seat to the movable part body; and a coil spring that is disposed between the seat and the movable part body and resists tilting of the seat with respect to the movable part body.

The biasing member may be an elastic body.

The elastic body may be a coil spring or rubber.

The chair may further include a backrest part fixed to the supporting part. According to the aforementioned configuration, it is possible to prevent a head part and both arms from being shaken.

The chair may further include a fixing member configured to fix the trunk of the user to the backrest part.

The fixing member may fix the part of the trunk of the user above the solar plexus to the backrest part.

The fixing member may fix the base of the neck or the shoulder blade of the trunk of the user to the backrest part.

The chair may further include a headrest fixed to the supporting part.

According to the present disclosure, a chair that can be provided for a low cost, is highly convenient, and is capable of providing highly effective exercise can be provided.

The above and other objects, features and advantages of the present disclosure will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not to be considered as limiting the present disclosure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side view of a lower limb exercise system;

FIG. 2 is a front view of the lower limb exercise system;

FIG. 3 is a front view of the lower limb exercise system;

FIG. 4 is a front view of a chair;

FIG. 5 is a perspective view of the chair;

FIG. 6 is a perspective view of the chair;

FIG. 7 is a perspective view of the chair;

FIG. 8 is a perspective view of the chair;

FIG. 9 is a perspective view of the chair;

FIG. 10 is a perspective view of the chair;

FIG. 11 is a front view of the lower limb exercise system;

FIG. 12 is a front view of the lower limb exercise system;

FIG. 13 is a side view of the chair;

FIG. 14 is a side view of the chair; and

FIG. 15 is a front view of the chair.

DESCRIPTION OF EMBODIMENTS

Although regular moderate exercise is suitable for maintaining good health, it is necessary to secure a regular time for exercise in order to do exercise regularly, and thus busy people tend to not exercise enough. However, even if it is difficult to secure a regular time for exercise, as long as a person can exercise his/her lower limbs while he/she remains in a sitting position, a certain amount of exercise can be done.

As exercise devices that enable a user to exercise his/her lower limbs while he/she remains in a sitting position, rowing exercise devices and stepping exercise devices have been known. Furthermore, even just putting both feet on a cushion and moving both legs up and down while he/she remains in the sitting position will exercise the lower limbs to some extent.

As a result of thorough research, the present inventors have found that causing a motion linkage to occur between the lower limbs and the trunk increases the effect of exercise obtained by exercising the lower limbs while a user remains in a sitting position, and have more particularly found that, if this motion linkage is made to occur during exercise of lower limbs while the user remains in the sitting position, exercise of trunk muscles represented by the rectus abdominis, transversus abdominis, and erector spinae muscles can be provided as well. The present inventors have also found that, when a user exercises his/her lower limbs while he/she remains in the sitting position, if the seat on which the user sits is fixed, a movement of the pelvis becomes slow, which inhibits the motion linkage between the lower limbs and the trunk, and thus that the motion linkage between the lower limbs and the trunk can be achieved by making the seat unstable.

If the exercise of the trunk muscles can be provided as described above, first, it is expected that the waist size of the user will be reduced. Second, since the rectus abdominis, transversus abdominis, and erector spinae muscles are strengthened, it becomes easy to maintain a posture in which the pelvis is tilted forward, which may contribute to solving problems such as a hunchback and a straight neck.

Further, if the motion linkage between the lower limbs and the trunk can be achieved as described above, the pelvis can be moved rapidly, which increases the flexibility of, in particular, the iliopsoas muscle and is expected to reduce chronic low back pain.

First Embodiment

Hereinafter, with reference to FIGS. 1 to 14, a first embodiment will be described.

FIG. 1 shows a lower limb exercise system 1. The lower limb exercise system 1 is one specific example of a rowing exercise system. As shown in FIG. 1, the lower limb exercise system 1 includes a rowing exercise device 2 and a chair 3.

The rowing exercise device 2 is one specific example of a device used for exercising the lower limbs while a user remains in a sitting position. The rowing exercise device 2 is a device used for rowing exercise while the user remains in the sitting position. The lower limb exercise system 1 may include, in place of the rowing exercise device 2, a stepping exercise device. The rowing exercise device 2 may be omitted.

The chair 3 is a chair on which the user U sits when he/she exercises his/her lower limbs (rowing exercise). In this embodiment, the chair 3 is separated from the rowing exercise device 2. Therefore, the distance between the rowing exercise device 2 and the chair 3 can be adjusted. However, the chair 3 may instead be integrally formed with the rowing exercise device 2.

FIGS. 2 and 3 each show a state in which the user U is doing exercise using the lower limb exercise system 1.

As shown in FIG. 2, the rowing exercise device 2 includes a device body 5 that rotatably supports an output axis, a pair of cranks 6 attached to the output axis, and a pair of pedals 7 attached to the pair of respective cranks 6. As shown in FIGS. 2 and 3, the user U performs rowing exercise by putting his/her both feet on the pair of pedals 7 and alternately stepping out. The device body 5 is configured to be able to adjust the load on the rotation of the output axis. The user U is able to perform rowing exercise with his/her preferred exercise load by adjusting the load on the rotation of the output axis.

FIG. 4 shows a front view of the chair 3. As shown in FIG. 4, the chair 3 includes a movable part 10, a supporting part 11, a restoration unit 12, and a stabilizing part 13.

The movable part 10 includes a seat 14 on which the user U sits.

The supporting part 11 supports the movable part 10 in such a way that it can be moved to the right and to the left. The “right and left” here is defined to be the right and the left seen from the user U. Likewise, “back and forth” or “backward and forward” is defined to be back and forth or backward and forward seen from the user U.

The restoration unit 12 biases the movable part 10 toward the neutral position in the right and the left. In FIG. 4, the movable part 10 is positioned at the neutral position. The neutral position is one specific example of a reference position.

Then, the supporting part 11 supports the movable part 10 in such a way that the movable part 10 descends as it is away from the neutral position.

The user U performs rowing exercise using the rowing exercise device 2 while sitting on the seat 14 of the chair 3.

According to the aforementioned configuration, the chair 3 that can be provided for a low cost, is highly convenient, and is capable of providing highly effective exercise can be provided.

Hereinafter, the chair 3 will be described in detail.

Supporting Part 11

The supporting part 11 is placed on the floor surface in a fixed manner. The supporting part 11 includes a leg part 20, a frame 21, and two rails 22.

The leg part 20 is a part that contacts the floor surface on which the chair 3 is installed.

The frame 21, which is supported by the leg part 20, supports the two rails 22. As shown in FIG. 5, the frame 21 includes a front frame part 21a disposed in the front, a back frame part 21b disposed in the back, a left frame part 21c disposed on the left side, and a right frame part 21d disposed on the right side. The front frame part 21a, the back frame part 21b, the left frame part 21c, and the right frame part 21d are coupled to one another so as to form a rectangle in a plan view. That is, the front frame part 21a and the back frame part 21b are coupled to each other via the left frame part 21c and the right frame part 21d. The left frame part 21c couples one end of the front frame part 21a to one end of the back frame part 21b. The right frame part 21d couples the other end of the front frame part 21a to the other end of the back frame part 21b.

The two rails 22 define the trajectory of the movement of the movable part 10 in the right and the left. The two rails 22 are disposed between the left frame part 21c and the right frame part 21d. The two rails 22 are extended from the left frame part 21c to the right frame part 21d. The two rails 22 couple the left frame part 21c to the right frame part 21d. The two rails 22 are disposed in the front-back direction so as to be away from each other. That is, the two rails 22 include a front rail part 22a disposed in the front and a back rail part 22b disposed in the back. Referring once again to FIG. 4, each of the rails 22 is bent so as to be convex upward. That is, each of the rails 22 is inclined so as to descend toward an end part EN thereof from a center CE thereof in the longitudinal direction of each of the rails 22. Each of the rails 22 is inclined so as to approach the floor surface toward the end part EN thereof from the center CE thereof in the longitudinal direction of each of the rails 22. In this embodiment, each of the rails 22 is formed in a V shape that is convex upward and opens downward. Therefore, the movable part 10 is guided so as to descend as it moves away from the neutral position when the movable part 10 moves in the right and the left along the two rails 22. In other words, as shown in FIG. 4, the supporting part 11 supports the movable part 10 in such a way that the movable part 10 is swung to the right and to the left about a roll axis 10R that is extended backward and forward, that is, in such a way that it rolls about the roll axis 10R. The roll axis 10R is set to be lower than the movable part 10 when the movable part 10 is positioned at the neutral position. The centroid point of the movable part 10 is guided so as to descend as it moves away from the neutral position when the movable part 10 moves in the right and the left along the two rails 22. Each of the rails 22 includes a left rail part 22c that is extended to the left from the center of the rail in the longitudinal direction of each of the rails 22 and a right rail part 22d that is extended to the right from the center of the rail in the longitudinal direction of each of the rails 22.

While each of the rails 22 has a V shape that is convex upward and opens downward in this embodiment, the shape of each of the rails 22 is not limited thereto. Each of the rails 22 may be a U shape that is convex upward and opens downward or a curved shape that is convex upward and opens downward. Each of the rails 22 may be extended typically in an arc shape or an elliptical arc shape so as to be convex upward and open downward.

In this embodiment, the left rail part 22c and the right rail part 22d that compose each of the rails 22 are integrally formed. However, the left rail part 22c and the right rail part 22d may be separated from each other and may be disposed so as to be away from each other.

Movable Part 10

Referring continuously to FIG. 4, the movable part 10 will be described.

As shown in FIG. 4, the movable part 10 includes a movable part body 30, the seat 14, a universal joint 31, a coil spring 32, and a pair of coupling units 33.

The pair of coupling units 33, the movable part body 30, and the seat 14 are disposed in this order in a direction away from the floor surface. The universal joint 31 and the coil spring 32 are disposed between the movable part body 30 and the seat 14.

The movable part body 30 is a plate body interposed between the supporting part 11 and the seat 14. The pair of coupling units 33 are provided on the lower surface of the movable part body 30. As shown in FIG. 7, the pair of coupling units 33 include a front coupling unit 33a and a back coupling unit 33b. The front coupling unit 33a corresponds to the front rail part 22a. The back coupling unit 33b corresponds to the back rail part 22b. Referring once again to FIG. 4, each of the coupling units 33 includes a pair of respective coupling parts 34. The pair of coupling parts 34 include a left coupling part 34a and a right coupling part 34b. The left coupling part 34a is slidably coupled to the left rail part 22c. The right coupling part 34b is slidably coupled to the right rail part 22d. For example, the left coupling part 34a may include a wheel rolling on the corresponding left rail part 22c, the wheel being shown by a dashed line, and a bracket that rotatably holds the wheel. The same holds true for the right coupling part 34b.

The seat 14 and the movable part body 30 are coupled to each other by the universal joint 31. Therefore, the seat 14 is supported by the movable part body 30 in such a way that it can turn around a yaw axis as shown in FIGS. 7 and 8. That is, the seat 14 is configured in such a way that it can yaw. The “yaw” means that it turns around the yaw axis. The “yaw axis” here means an axis that is extended along the vertical direction, which is a direction in which the gravity acts. Alternatively, the “yaw axis” may be an axis that is extended along the thickness direction of the movable part body 30. Likewise, the seat 14 is supported by the movable part body 30 so that it can be tilted backward and forward with respect to the movable part body 30, as shown in FIG. 9. That is, the seat 14 is configured in such a way that it can pitch. The “pitch” means that it turns around a pitch axis. The “pitch axis” here means an axis that is extended in the right and the left. The pitch axis passes through a joint part 31a of the universal joint 31. Therefore, the pitch axis is set to be lower than the seat 14. Likewise, the seat 14 is supported by the movable part body 30 so that it can be tilted to the right and to the left with respect to the movable part body 30 as shown in FIG. 10. That is, the seat 14 is configured so that it can roll not only by the movable part body 30 and the supporting part 11 but also by the universal joint 31. The roll of the seat 14 by the universal joint 31 means turning about the roll axis that passes through the joint part 31a of the universal joint 31. The “roll axis” means an axis that is extended backward and forward.

Referring once again to FIG. 4, the coil spring 32 that resists tilting of the seat 14 with respect to the movable part body 30 is disposed between the seat 14 and the movable part body 30. The upper end of the coil spring 32 contacts the seat 14 and the lower end of the coil spring 32 contacts the movable part body 30. In this embodiment, the coil spring 32 is coaxially disposed with the universal joint 31. In other words, the coil spring 32 is disposed so as to house the universal joint 31 inside a helical structure of the spring. When, for example, the seat 14 is tilted forward with respect to the movable part body 30, the upper end of the coil spring 32 is elastically displaced forward, and at the same time, an elastic restoring force of the coil spring 32 causes the seat 14 to return to the state before the tilting. Note that the upper end of the coil spring 32 is not fixed to the seat 14 so as not to inhibit turn of the seat 14 about the yaw axis with respect to the movable part body 30.

The user U sits on the seat 14. The seat 14 includes a seating surface 14a opposed to the buttocks of the user U. The seating surface 14a is inclined forward in such a way that the pelvis of the user U is inclined forward when the user U sits on the seat 14. That is, the front part of the seating surface 14a is lower than the back part thereof.

Restoration Unit 12

The restoration unit 12 is one specific example of a biasing member. The restoration unit 12 biases the movable part 10 toward the neutral position in the right and the left. In this embodiment, the restoration unit 12 is an elastic body. That is, the restoration unit 12 includes a pair of restoring coil springs 40. The pair of restoring coil springs 40 include a left restoring coil spring 40a that is provided between the center CE of each of the rails 22 and the left coupling part 34a and a right restoring coil spring 40b that is provided between the center CE of each of the rails 22 and the right coupling part 34b. The left restoring coil spring 40a and the right restoring coil spring 40b are formed as separate bodies.

When the movable part 10 moves to the left with the aforementioned configuration, the left restoring coil spring 40a is elongated and the elastic restoring force of the left restoring coil spring 40a biases the movable part 10 toward the neutral position. Likewise, when the movable part 10 moves to the right, the right restoring coil spring 40b is elongated, and the elastic restoring force of the right restoring coil spring 40b biases the movable part 10 toward the neutral position.

While the elastic body that forms the restoration unit 12 is a coil spring in this embodiment, it may instead be another elastic body such as rubber.

While the restoration unit 12 is formed of the pair of restoring coil springs 40 in this embodiment, it may instead be composed of one coil spring. In this case, in general, one coil spring is provided between the left coupling part 34a and the right coupling part 34b, and the center of one coil spring in the longitudinal direction is fixed to the center CE. The restoration unit 12 may be provided between the frame 21 and the movable part 10 instead of being provided between each of the rails 22 and the movable part 10.

When the user U kicks out his/her right leg as shown in FIG. 2 with the aforementioned configuration, his/her pelvis slightly moves to the right side, which causes the movable part body 30 to slightly move to the right side. At this time, since each of the rails 22 is inclined so as to descend toward the end part EN thereof from the center CE thereof, the movement of the movable part body 30 to the right side is amplified and the amount of movement of the pelvis increases. Since the pelvis moves a lot, the trunk muscles of the user U are activated in conjunction with a stepping motion of the shank of the user U, which provides exercise of the trunk muscles. The same holds true for a case in which the user U kicks out his/her left leg.

Further, when the user U kicks out his/her right leg, his/her pelvis turns in a counterclockwise direction around the yaw axis in a plan view. Since the seat 14 is configured so as to be able to turn about the yaw axis with respect to the movable part body 30, this pelvic turning movement is smoothly performed. The same holds true for a case in which the user U kicks out his/her left leg. In this manner, the pelvis moves in the right and the left and turns about the yaw axis, which causes the pelvis to be inclined forward and thus leads the user U to maintain a good posture with his/her pelvis stood upright.

The meaning that the restoration unit 12 is provided will be explained. If the restoration unit 12 is not provided, once the movable part 10 is deviated from the neutral position in the right and the left, it is difficult to return the movable part 10 to the neutral position. Specifically, although the user U is able to instantaneously release the load on the movable part 10, the user U cannot return the movable part 10 to the neutral position at the same timing. On the other hand, when the restoration unit 12 is provided, the user U only needs to instantaneously release the load on the movable part 10 so that the movable part 10 is biased toward the neutral position, whereby the movable part 10 can be easily returned to the neutral position using the inertia obtained when the movable part 10 is biased. In some embodiments, the elastic restoring force of the restoration unit 12 can be changed in accordance with the physique and muscle strength of the user U. That is, when a user U who is not familiar with the use of trunk muscles uses the chair 3, the spring constant of the restoration unit 12 may be set to be large, so that the movable part 10 proactively returns to the neutral position. On the other hand, when a user U who is familiar with the use of trunk muscles uses the chair 3, the spring constant of the restoration unit 12 may be set to be small. When the spring constant of the restoration unit 12 is small, the movable part 10 does not tend to return to the neutral position, and trunk muscles need to be activated every time the movable part 10 is made to return to the neutral position. In this way, by changing the spring constant of the restoration unit 12, the load applied to the trunk muscles can be adjusted.

In this embodiment, when the movable part 10 moves to the right side, the seating surface 14a of the seat 14 is inclined to the right side. Likewise, when the movable part 10 moves to the left side, the seating surface 14a of the seat 14 is inclined to the left side. The tilt angles of the seating surface 14a in the above cases do not always coincide with the tilt angles of the pelvis. In this embodiment, the seat 14 can be tilted to the right and to the left with respect to the movable part body 30 by the universal joint 31, whereby the tilt angle of the seating surface 14a of the seat 14 follows the tilt angle of the pelvis of the user U and thus the comfort level of the seat 14 at the time of exercise is not impaired.

Stabilizing Part 13

Incidentally, when the motion linkage between the lower limbs and the trunk occurs, as shown in FIGS. 11 and 12, the head part and the both arms connected to the trunk are generally shaken in the right and the left. When, for example, the head part is shaken in the right and the left, it becomes difficult to read text and the like on a display placed on a desk. A similar problem occurs with a tablet display held by both hands. Further, when, for example, the both arms are shaken in the right and the left, it becomes difficult to input text by a keyboard placed on a desk. In this way, the motion linkage between the lower limbs and the trunk makes it difficult for a user to work or watch a movie during exercise. In some embodiments, the head part and the both arms may be prevented from being shaken while achieving the motion linkage between the lower limbs and the trunk.

In order to achieve the above object, as shown in FIGS. 13 and 14, the chair 3 according to this embodiment includes the stabilizing part 13 that stabilizes the posture of the user U while preventing the head part and the both arms of the user U from being shaken.

The stabilizing part 13 includes a backrest part 50, a position adjustment part 51, a coupling unit 52, and a fixing belt unit 53.

The backrest part 50 is a part opposed to the back of the user U. The backrest part 50 is supported by the position adjustment part 51. The backrest part 50 includes a pair of lumbar supports 50a. The pair of respective lumbar supports 50a are disposed so as to be opposed to the right area and the left area of the back of the user U. The pair of lumbar supports 50a are supported by the position adjustment part 51 via an elastic member. Therefore, each of the lumbar supports 50a can be swung to the right and to the left and upward and downward, and can follow the movement of the trunk of the user U. That is, even when the trunk of the user U turns around the yaw axis, it is possible to maintain a state in which at least one of the pair of lumbar supports 50a contacts the back of the user U.

The position adjustment part 51 is fixed to the frame 21 via the coupling unit 52. As shown in FIG. 14, the position adjustment part 51 includes a bellows shutter 51a that can be extended and retracted in the front-back direction and a grip 51b for adjusting the degree of extension and retraction of the bellows shutter 51a. The bellows shutter 51a is formed of a plurality of pairs of bellows frames 51c, each forming the X shape, aligned in the front-back direction. A screw 51d for adjusting the tilt angle of the pair of bellows frames 51c is coupled to the grip 51b. When the grip 51b is operated with the aforementioned configuration, the tilt angle of the pair of bellows frames 51c is increased or decreased, whereby the bellows shutter 51a is extended or retracted and the backrest part 50 moves back and forth. Therefore, by causing the backrest part 50 to move back and forth by operating the position adjustment part 51 in accordance with the skeleton of the user U, the backrest part 50 can be disposed in a suitable position with respect to the back of the user U.

The coupling unit 52 is configured in such a way that it can be extended and retracted vertically. Accordingly, it is possible to cause the backrest part 50 to move vertically in accordance with the skeleton of the user U and dispose the backrest part 50 in a suitable position with respect to the back of the user U.

The fixing belt unit 53 is used to fix the trunk of the user U to the backrest part 50. Specifically, as shown in FIG. 2, the fixing belt unit 53 is used to fix the part of the trunk of the user U above the solar plexus (the joint of the twelfth dorsal vertebra and the first lumbar vertebra) to the backrest part 50. This is because, if the part of the trunk of the user U above the solar plexus is fixed to the backrest part 50, it becomes possible to prevent shaking of the head part and the both arms of the user U, and the motion linkage between the lower limbs and the trunk is not inhibited since the pelvis is allowed to be swung.

In some embodiments, the fixing belt unit 53 fixes the base of the neck (the joint of the seventh cervical vertebra and the first dorsal vertebra) or the shoulder blade of the trunk of the user U to the backrest part 50. By fixing the base of the neck of the trunk of the user U to the backrest part 50, shaking of the head part can be efficiently prevented. Further, by fixing the shoulder blade of the trunk of the user U to the backrest part 50, shaking of the both arms can be efficiently prevented.

Referring continuously to FIG. 2, the fixing belt unit 53 is typically configured to fix the trunk of the user U to the backrest part 50 by coupling both end parts of the belt 53a held by the backrest part 50 by the buckle 53b. At this time, the length of the belt 53a may be adjusted using the buckle 53b.

Alternatively, the both end parts of the belt 53a held by the backrest part 50 may be coupled by a hook-and-loop fastener or the belt 53a itself may be extended and retracted.

Described above is the first embodiment of the present disclosure. The first embodiment includes the following features.

As shown in FIGS. 1 to 4, the chair 3 includes the movable part 10 including the seat 14 on which the user U sits; the supporting part 11 configured to support the movable part 10 in such a way that the movable part 10 can be moved to the right and to the left; and the restoration unit 12, which is a biasing member for biasing the movable part 10 toward the neutral position in the right and the left. The supporting part 11 supports the movable part 10 in such a way that the movable part 10 descends as it is away from the neutral position. According to the aforementioned configuration, a chair that can be provided for a low cost, is highly convenient, and is capable of providing highly effective exercise can be provided.

Further, as shown in FIGS. 1 to 4, the chair 3 includes the movable part 10 including the seat 14 on which the user U sits; the supporting part 11 configured to support the movable part 10 in such a way that the movable part 10 can be moved to the right and to the left; and the restoration unit 12, which is a biasing member for biasing the movable part 10 toward the neutral position in the right and the left. The supporting part 11 supports the movable part 10 in such a way that the movable part 10 is swung to the right and to the left about the roll axis 10R that is extended backward and forward. The roll axis 10R is set below the movable part 10 when the movable part 10 is positioned at the neutral position. According to the aforementioned configuration, a chair that can be provided for a low cost, is highly convenient, and is capable of providing highly effective exercise can be provided.

Further, the supporting part 11 includes the two rails 22 that define the trajectory of the movement of the movable part 10 in the right and the left. The two rails 22 are inclined so as to descend toward the end part EN thereof from the center CE thereof in the longitudinal direction of the two rails 22. The movable part 10 moves along the two rails 22 of the supporting part 11. Note that the supporting part 11 may be configured to include only one rail 22, not two rails 22.

Each of the rails 22 includes the right rail part 22d that is extended to the right from the center CE and the left rail part 22c that is extended to the left from the center CE. The movable part 10 includes the right coupling part 34b slidably coupled to the right rail part 22d and the left coupling part 34a slidably coupled to the left rail part 22c.

As shown in FIGS. 7 and 8, the seat 14 is configured so as to be able to turn about the yaw axis. According to the aforementioned configuration, the motion linkage between the lower limbs and the trunk is achieved more effectively.

As shown in FIG. 4, the movable part 10 further includes the movable part body 30 interposed between the supporting part 11 and the seat 14. The seat 14, which is mounted on the movable part body 30, is configured so as to be able to turn about the yaw axis with respect to the movable part body 30. According to the aforementioned configuration, the motion linkage between the lower limbs and the trunk is achieved more effectively.

As shown in FIGS. 9 and 10, the seat 14 is configured so that it can be tilted to the right and to the left and backward and forward with respect to the movable part body 30. According to the aforementioned configuration, a good fit of the seating surface 14a of the seat 14 to the buttocks of the user U while the movable part 10 is moving to the right and to the left can be provided.

As shown in FIG. 4, the movable part 10 further includes the universal joint 31 that couples the seat 14 to the movable part body 30, and the coil spring 32 that is disposed between the seat 14 and the movable part body 30 and resists tilting of the seat 14 with respect to the movable part body 30. According to the aforementioned configuration, it is possible to prevent the seat 14 from tilting excessively with respect to the movable part body 30.

The restoration unit 12 is formed of an elastic body. The restoration unit 12 includes, as the elastic body, the restoring coil springs 40. The restoration unit 12 may include, as the elastic body, rubber in place of the restoring coil springs 40.

As shown in FIGS. 13 and 14, the chair 3 further includes the backrest part 50 fixed to the supporting part 11. According to the aforementioned configuration, it is possible to prevent shaking of the head part and the both arms.

The chair 3 further includes the fixing belt unit 53, which is a fixing member for fixing the trunk of the user U to the backrest part 50.

As shown in FIG. 2, the fixing belt unit 53 fixes the part of the user's trunk above the solar plexus to the backrest part 50. In some embodiments, the fixing belt unit 53 fixes the base of the neck or the shoulder blade of the trunk of the user U to the backrest part 50. According to the aforementioned configuration, it is possible to efficiently prevent shaking of the head part and the both arms.

Second Embodiment

Hereinafter, with reference to FIG. 15, a second embodiment will be described.

As shown in FIG. 15, in this embodiment, the chair 3 includes a headrest 60 fixed to a frame 21. In this embodiment, the headrest 60 is fixed to the frame 21 via a coupling unit 52. According to this configuration, it is possible to efficiently prevent the head part of the user U from being shaken.

While the first and second embodiments of the present disclosure have been described above, each of the aforementioned embodiments may be changed as follows.

In order to prevent the part of the trunk of the user U above the solar plexus from being shaken, the chair 3 may include a pair of arms that hold the part of the trunk of the user U above the solar plexus from the right and the left. The pair of arms are fixed to the supporting part 11.

Further, in order to prevent both arms of the user U from being shaken, the chair 3 may include a pair of armrests. The pair of armrests are fixed to the supporting part 11.

Further, in each of the aforementioned embodiments, the seat 14 is able to turn about the yaw axis with respect to the movable part body 30. However, alternatively, the seat 14 may be configured so as not to be able to turn about the yaw axis with respect to the movable part body 30 and to be able to turn about the yaw axis with respect to the supporting part 11. In this case, generally, a thrust bearing may be provided between the frame 21 and the leg part 20 so that the frame 21 can be made so as to be able to turn about the yaw axis with respect to the leg part 20. Alternatively, the movable part body 30 may be made so as to be able to turn about the yaw axis with respect to the pair of coupling parts 34, or the movable part body 30 may have a two-layer structure formed of an upper stage part and a lower stage part that overlap each other vertically, and a thrust bearing may be interposed between the upper stage part and the lower stage part. That is, as long as the seat 14 can turn about the yaw axis with respect to the space while the user U keeps sitting on the seat 14, structure for attaining this configuration is not limited.

From the disclosure thus described, it will be obvious that the embodiments of the disclosure may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure, and all such modifications as would be obvious to one skilled in the art are intended for inclusion within the scope of the following claims.

Claims

1. A chair comprising: a movable part including a seat on which a user sits;a supporting part configured to support the movable part in such a way that it can be moved to the right and to the left, the supporting part comprising a rail that defines a trajectory of the movement of the movable part in the right and the left, the rail being inclined so as to descend toward an end part of the rail from a center of the rail in the longitudinal direction, the movable part movable along the rail of the supporting part; anda biasing member configured to bias the movable part toward a neutral position in the right and the left,wherein the supporting part supports the movable part in such a way that a center of the movable part descends as the movable part is away from the neutral position.

2. The chair according to claim 1, wherein the rail comprises a right rail part that is extended to the right from the center of the rail and a left rail part that is extended to the left from the center of the rail, andthe movable part comprises a right coupling part slidably coupled to the right rail part and a left coupling part slidably coupled to the left rail part.

3. The chair according to claim 1, wherein the seat is configured so as to be able to turn about a yaw axis.

4. The chair according to claim 1, wherein the movable part further comprises a movable part body interposed between the supporting part and the seat, andthe seat is mounted on the movable part body and is configured so as to be able to turn about a yaw axis with respect to the movable part body.

5. The chair according to claim 4, wherein the seat is configured so that it can be tilted backward and forward with respect to the movable part body.

6. The chair according to claim 4, wherein the seat is configured so that it can be tilted to the right and to the left and backward and forward with respect to the movable part body.

7. The chair according to claim 6, wherein the movable part further comprises: a universal joint configured to couple the seat to the movable part body; anda coil spring that is disposed between the seat and the movable part body and resists tilting of the seat with respect to the movable part body.

8. The chair according to claim 1, wherein the movable part further comprises a movable part body interposed between the supporting part and the seat, andthe seat is mounted on the movable part body and is configured so as to be able to turn about a yaw axis with respect to the supporting part.

9. The chair according to claim 1, wherein the biasing member is an elastic body.

10. The chair according to claim 9, wherein the elastic body is a coil spring or rubber.

11. The chair according to claim 1, further comprising a backrest part fixed to the supporting part.

12. The chair according to claim 11, further comprising a fixing member configured to fix a trunk of the user to the backrest part.

13. The chair according to claim 12, wherein the fixing member is configured to fix a part of the trunk of the user above a solar plexus to the backrest part.

14. The chair according to claim 13, wherein the fixing member is configured to fix a base of a neck or a shoulder blade of the trunk of the user to the backrest part.

15. The chair according to claim 1, further comprising a headrest fixed to the supporting part.

16. A chair comprising: a movable part including a seat on which a user sits;a supporting part configured to support the movable part in such a way that it can be moved to the right and to the left, the supporting part comprising a rail that defines a trajectory of the movement of the movable part in the right and the left, the rail being inclined so as to descend toward an end part of the rail from a center of the rail in the longitudinal direction, the movable part movable along the rail of the supporting part; anda biasing member configured to bias the movable part toward a neutral position in the right and the left, whereinthe supporting part supports the movable part in such a way that the movable part is swung to the right and to the left about a roll axis extending backward and forward, andthe roll axis is set to be lower than the movable part when the movable part is positioned at the neutral position.

17. A chair comprising: a movable part including a seat on which a user sits;a supporting part configured to support the movable part in such a way that it can be moved to the right and to the left, the supporting part comprising a rail that defines a trajectory of the movement of the movable part in the right and the left, the rail being inclined so as to descend toward an end part of the rail from a center of the rail in the longitudinal direction, the movable part movable along the rail of the supporting part; andan elastic body for biasing the movable part toward a neutral position in the right and the left,wherein the supporting part supports the movable part in such a way that a center of the movable part descends as the movable part is away from the neutral position.