Chair, forward tilt angle changing device, and forward tilt angle changing method

Abstract

To provide a chair enabling shortening of time during which posture of a user is maintained at a sitting position.SOLUTION: A chair 1 comprises a changing unit 20 and a control unit 40. The changing unit 20 changes a forward inclination angle between a first angle and a second angle larger than the first angle, wherein the forward inclination angle is an angle at which a seat surface SS inclines with respect to a horizontal surface and which becomes larger the higher a position in a vertical direction of a rear edge of the seat surface SS with respect to a front edge of the seat surface SS. The control unit 40 changes the forward inclination angle from the first angle to the second angle and controls the changing unit 20 so that the forward inclination angle maintains at the second angle for a first maintenance period.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a chair, a forward tilt angle changing device, and a forward tilt angle changing method.

Background Art

[0002] There is known a chair configured such that the forward tilt angle of a seat surface on which a user sits changes between a first angle and a second angle. The forward tilt angle is an angle at which the seat surface is inclined with respect to a horizontal plane, and is an angle that increases as the position of the rear edge of the seat surface in the vertical direction with respect to the front edge of the seat surface becomes higher. For example, the chair described in Patent Document 1 repeats the rocking of the seat surface by alternately and continuously providing a period in which the forward tilt angle is increased and a period in which the forward tilt angle is decreased.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, it is known that if the period during which the user's posture is maintained in the seated position becomes excessively long, it will harm the user's health. For example, it is known that there is a correlation between this period and the probability of suffering from diseases such as musculoskeletal disorders, heart diseases, or lifestyle-related diseases. However, in the above chair, the user's posture is maintained in the seated position. For this reason, there has been a risk that the time during which the user's posture is maintained in the seated position becomes excessively long.

[0005] One of the objects of the present invention is to shorten the time during which the user's posture is maintained in the seated position.

Means for Solving the Problems

[0006] On one side, the chair has a seating surface on which the user sits. The chair includes a changing unit and a control unit. The changing unit changes the forward tilt angle, which is the angle at which the seating surface is inclined with respect to the horizontal plane and increases as the position of the rear edge of the seating surface in the vertical direction relative to the front edge of the seating surface becomes higher, between a first angle and a second angle greater than the first angle. The control unit controls the changing unit to change the forward tilt angle from the first angle to the second angle and maintain the forward tilt angle at the second angle for a predetermined first maintenance period.

[0007] On another side, the forward tilt angle changing device changes the forward tilt angle, which is the angle at which the seating surface on which the user sits is inclined with respect to the horizontal plane and increases as the position of the rear edge of the seating surface in the vertical direction relative to the front edge of the seating surface becomes higher. The forward tilt angle changing device includes a changing unit and a control unit. The changing unit changes the tilt angle between a first angle and a second angle greater than the first angle. The control unit controls the changing unit to change the forward tilt angle from the first angle to the second angle and maintain the forward tilt angle at the second angle for a predetermined first maintenance period.

[0008] On another side, the forward tilt angle changing method changes the forward tilt angle, which is the angle at which the seating surface on which the user sits is inclined with respect to the horizontal plane and increases as the position of the rear edge of the seating surface in the vertical direction relative to the front edge of the seating surface becomes higher. The forward tilt angle changing method includes changing the forward tilt angle from a first angle to a second angle and maintaining the forward tilt angle at the second angle for a predetermined first maintenance period.

Advantages of the Invention

[0009] The time for maintaining the user's posture in the seated position can be shortened.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0011] Hereinafter, each embodiment of the chair, the forward tilt angle changing device, and the forward tilt angle changing method of the present invention will be described with reference to FIGS. 1 to 11.

[0012] <First Embodiment> (Overview) The chair of the first embodiment has a seat surface on which the user sits. The chair includes a changing unit and a control unit. The changing unit changes the forward tilt angle, which is the angle at which the seat surface is inclined with respect to the horizontal plane and increases as the position of the rear edge of the seat surface in the vertical direction with respect to the front edge of the seat surface becomes higher, between a first angle and a second angle larger than the first angle. The control unit controls the changing unit to change the forward tilt angle from the first angle to the second angle and to maintain the forward tilt angle at the second angle for a predetermined first maintenance period.

[0013] According to this, the forward tilt angle is maintained at the second angle for the first maintenance period. As a result, it becomes difficult for the user to maintain the posture in the seated position. As a result, the user is induced to change the posture to the standing position. Therefore, the time during which the user's posture is maintained in the seated position can be shortened. Next, the chair of the first embodiment will be described in detail with reference to FIGS. 1 to 4.

[0014] (Configuration) Hereinafter, as shown in FIGS. 1 and 2, the chair 1 of the first embodiment will be described using a right-handed orthogonal coordinate system having an x-axis, a y-axis, and a z-axis. In this specification, the same coordinate system is also used in FIG. 9 described later.

[0015] In this example, the x-axis direction, the y-axis direction, and the z-axis direction may be respectively represented as the left-right direction of the chair 1, the front-back direction of the chair 1, and the up-down direction of the chair 1. Also, in this example, the positive direction of the x-axis, the negative direction of the x-axis, the positive direction of the y-axis, the negative direction of the y-axis, the positive direction of the z-axis, and the negative direction of the z-axis may be respectively represented as the left direction of the chair 1, the right direction of the chair 1, the rear direction of the chair 1, the front direction of the chair 1, the upward direction of the chair 1, and the downward direction of the chair 1. In this example, the positive direction of the z-axis and the negative direction of the z-axis respectively coincide with the vertically upward direction and the vertically downward direction.

[0016] As shown in FIG. 1, the chair 1 includes a support portion 10, a changing portion 20, a seat portion 30 whose upper end surface constitutes a seat surface SS, and a control portion 40. In this example, the chair 1 includes a backrest portion (not shown) that supports the user's back when the user is seated. In this example, the backrest portion is fixed to the support portion 10. Note that the chair 1 may not include a backrest portion.

[0017] The support part 10 extends in the vertical direction. The lower end of the support part 10 is placed on the ground or the floor surface. In this example, the support part 10 includes a columnar body extending in the vertical direction, a plurality of legs radially extending from the lower end part of the columnar body, and casters provided at the tips of the respective legs. Note that the support part 10 may not be provided with casters. Further, instead of the plurality of legs and the plurality of casters, the support part 10 may be provided with a pedestal such as a disk provided at the lower end part of the columnar body. Further, instead of the columnar body, the plurality of legs, and the plurality of casters, the support part 10 may include three or more (for example, four) legs. Also in this case, casters may be provided at the tips of the respective legs.

[0018] In this example, the length of the support part 10 in the vertical direction (in other words, the height of the support part 10) is adjustable. The function of adjusting the height of the support part 10 may be realized using a known technique. Note that the height of the support part 10 may not be adjustable. The support part 10 supports the changing part 20. In this example, the upper end part of the support part 10 supports the changing part 20.

[0019] The changing part 20 includes a first flat plate 21, a second flat plate 22, a connecting part 23, a spacer 24, a housing part 25, an air quantity changing part 26, and an angle sensor 27.

[0020] The first flat plate 21 extends in a plane orthogonal to the z-axis (in this example, the horizontal plane). In this example, the first flat plate 21 has a rectangular shape having two pairs of sides extending in the x-axis and the y-axis respectively. Note that the first flat plate 21 may have a shape other than the rectangular shape (for example, a rounded rectangular shape, a square shape, or a rounded square shape, etc.). The lower end surface of the first flat plate 21 is fixed to the support part 10.

[0021] In this example, the support portion 10 horizontally supports the first flat plate 21. In this example, the support portion 10 can adjust the forward tilt angle of the first flat plate 21. The forward tilt angle of the first flat plate 21 is the angle at which the first flat plate 21 is inclined with respect to the horizontal plane, and is an angle that increases as the position of the rear edge of the first flat plate 21 in the vertical direction with respect to the front edge of the first flat plate 21 becomes higher. In other words, the forward tilt angle of the first flat plate 21 is the counterclockwise rotation angle when viewing the chair 1 from the left side position of the chair 1 toward the right side of the chair 1.

[0022] The function of adjusting the forward tilt angle of the first flat plate 21 may be realized using known techniques. Note that the support portion 10 may not be able to adjust the forward tilt angle of the first flat plate 21.

[0023] The second flat plate 22 extends in a plane parallel to the first flat plate 21 (in this example, the horizontal plane). In this example, the second flat plate 22 has a rectangular shape with two pairs of sides extending along the x-axis and the y-axis respectively. Note that the second flat plate 22 may have a shape other than a rectangular shape (for example, a rounded rectangular shape, a square shape, or a rounded square shape, etc.). The second flat plate 22 faces the first flat plate 21 above the first flat plate 21. A seat portion 30 is fixed to the upper end surface of the second flat plate 22.

[0024] The connecting portion 23 connects the first flat plate 21 and the second flat plate 22 at the front end portions of the first flat plate 21 and the second flat plate 22 so that the second flat plate 22 can swing with respect to the first flat plate 21. The central axis of the swing of the second flat plate 22 with respect to the first flat plate 21 extends in the x-axis direction (in other words, the left-right direction of the chair 1). In this example, the connecting portion 23 includes a hinge (in other words, a hinge).

[0025] The spacer 24 is interposed between the first flat plate 21 and the second flat plate 22 at the rear end portions of the first flat plate 21 and the second flat plate 22 so as to separate the first flat plate 21 and the second flat plate 22 by a predetermined gap length. In this example, the spacer 24 is fixed to the first flat plate 21. Note that the spacer 24 may be fixed to the second flat plate 22. Also, the spacer 24 may be integral with at least one of the first flat plate 21 and the second flat plate 22.

[0026] In this example, the spacer 24 is configured such that the first flat plate 21 and the second flat plate 22 are parallel to each other. Note that the spacer 24 may be configured such that the second flat plate 22 is inclined with respect to the first flat plate 21.

[0027] The accommodating portion 25 accommodates air and its volume changes according to the amount of air accommodated. The accommodating portion 25 is interposed between the second flat plate 22 and the first flat plate 21.

[0028] The air amount changing portion 26 changes the amount of air accommodated in the accommodating portion 25 according to the control of the control portion 40. In this example, the air amount changing portion 26 includes a switching valve, an air compressor, a pressure regulating valve, and a vacuum pump. The switching valve switches between the inflow of air into the accommodating portion 25 and the outflow of air from the accommodating portion 25. The air compressor compresses air and sends the compressed air to the accommodating portion 25 via the switching valve. The pressure regulating valve adjusts the pressure of the air between the air compressor and the switching valve. The vacuum pump discharges air from the accommodating portion 25 via the switching valve. In this example, the accommodating portion 25 and the air amount changing portion 26 correspond to a rocking portion that rocks the second flat plate 22 with respect to the first flat plate 21.

[0029] The angle sensor 27 detects the angle of the second flat plate 22 with respect to the horizontal plane. In this example, the angle detected by the angle sensor 27 corresponds to the forward tilt angle of the seat surface SS. The forward tilt angle of the seat surface SS is the angle at which the seat surface SS is inclined with respect to the horizontal plane, and is an angle that increases as the position of the rear edge of the seat surface SS in the vertical direction with respect to the front edge of the seat surface SS becomes higher. In other words, the forward tilt angle of the seat surface SS is the counterclockwise rotation angle when viewing the chair 1 from the left side position of the chair 1 toward the right side of the chair 1.

[0030] The angle sensor 27 is fixed to the second flat plate 22 (in this example, the upper end surface of the second flat plate 22). In this example, the angle sensor 27 is located at the rear end portion of the second flat plate 22. In this example, the angle sensor 27 includes an acceleration sensor. Note that the angle sensor 27 may detect the angle of the second flat plate 22 with respect to the vertical direction.

[0031] The seat part 30 is fixed to the upper end surface of the second flat plate 22. The upper end surface of the seat part 30 constitutes the seat surface SS. In this example, the seat surface SS has a curved surface along at least a part of the user's buttocks when the user is seated. Note that the seat surface SS may be a flat surface. In this example, the front end of the seat part 30 is located in front of the front end of the changing part 20 in the front-rear direction of the chair 1.

[0032] The control unit 40 includes a processing device and a storage device. In this example, at least a part of the control unit 40 is constituted by an LSI (Large Scale Integration) circuit. Note that at least a part of the control unit 40 may be constituted by a programmable logic circuit (for example, a PLD (Programmable Logic Device) or an FPGA (Field-Programmable Gate Array)).

[0033] The control unit 40 controls the air amount changing part 26 by the processing device executing the program stored in the storage device. In this example, the control by the control unit 40 is performed by the control unit 40 transmitting and receiving signals to and from each of the air amount changing part 26 and the angle sensor 27. Also, in this example, the control unit 40 receives an instruction input by an operation of the user of the chair 1. Note that the detailed description of the functions of the control unit 40 is supplemented by the description of the operation of the chair 1 described later.

[0034] For example, the processing device may include a CPU (Central Processing Unit), an MPU (Micro Processing Unit), or a DSP (Digital Signal Processor). For example, the storage device may include a RAM (Random Access Memory), a semiconductor memory, an organic memory, an HDD (Hard Disk Drive), or an SSD (Solid State Drive).

[0035] With such a configuration, when the air volume changing unit 26 increases the amount of air accommodated in the accommodating unit 25 according to the control of the control unit 40, the second flat plate 22 swings with respect to the first flat plate 21 so that the forward tilt angle increases. As a result, as shown in FIG. 2, the forward tilt angle becomes larger than the case shown in FIG. 1. Further, when the air volume changing unit 26 decreases the amount of air accommodated in the accommodating unit 25 according to the control of the control unit 40, the second flat plate 22 swings with respect to the first flat plate 21 so that the forward tilt angle decreases. In this example, the changing unit 20 and the control unit 40 correspond to the forward tilt angle changing device.

[0036] (Operation) Next, an example of the operation of the chair 1 will be described with reference to FIGS. 3 and 4. In this example, the control unit 40 executes the forward tilt angle control process represented by the flowchart in FIG. 3. The control unit 40 waits until it receives a start instruction input by the user of the chair 1 (the "No" determination in step S101 of FIG. 3). Then, when a start instruction is input by the user of the chair 1, the control unit 40 receives the input start instruction.

[0037] Thereby, the control unit 40 proceeds to step S102 of FIG. 3 and changes the forward tilt angle to the seating angle (step S102 of FIG. 3). In this example, the control unit 40 controls the air volume changing unit 26 so that the forward tilt angle detected by the angle sensor 27 coincides with the seating angle.

[0038] The seating angle is a forward tilt angle at which the user of the chair 1 can easily maintain the posture in the seated position (in this example, the upright seated position or the straddle seated position). In this example, the seating angle is 0 degrees. Note that the seating angle may be an angle of -5 degrees to 5 degrees. In this example, the seating angle corresponds to the first angle. Then, the control unit 40 controls the air volume changing unit 26 so as to maintain the forward tilt angle detected by the angle sensor 27 at the seating angle. Thereby, the user of the chair 1 sits on the seat surface SS of the chair 1. In other words, the user of the chair 1 sits on the chair 1.

[0039] Next, the control unit 40 starts measuring the elapsed time (step S103 in FIG. 3). Next, the control unit 40 waits until the forward tilt start time arrives (judgment of "No" in step S104 in FIG. 3). In this example, the forward tilt start time is the time when a predetermined waiting time has elapsed after the start instruction is input by the user. In this example, the waiting time is 1 hour. Note that the waiting time may be a time of 20 minutes to 4 hours (preferably 30 minutes to 1 hour).

[0040] Thereafter, when the forward tilt start time arrives (time T11 in FIG. 4 in this example), the control unit 40 changes the forward tilt angle to the standing posture induction angle (step S105 in FIG. 3). In this example, the control unit 40 controls the air amount changing unit 26 so as to increase the forward tilt angle detected by the angle sensor 27 at a predetermined acceleration rate. In this example, the acceleration rate is 5 degrees / minute. Note that the acceleration rate may be a speed of 1 degree / minute to 80 degrees / minute (preferably 2 degrees / minute to 10 degrees / minute).

[0041] The control unit 40 controls the air amount changing unit 26 so as to continue increasing the forward tilt angle until the forward tilt angle detected by the angle sensor 27 matches the standing posture induction angle. The standing posture induction angle is larger than the sitting angle.

[0042] The standing posture induction angle is a forward tilt angle at which it is difficult for the user of the chair 1 to maintain the posture in the sitting position. In other words, the standing posture induction angle is a forward tilt angle that induces (or promotes) the user of the chair 1 to change the posture from the sitting position to the standing position. In this example, the standing posture induction angle is 35 degrees. Note that the standing posture induction angle may be an angle of 30 degrees to 45 degrees. It is preferable that the standing posture induction angle is an angle of 35 degrees to 40 degrees. In this example, the standing posture induction angle corresponds to the second angle.

[0043] Then, the control unit 40 waits until a predetermined standing guidance time elapses from the time when the forward tilt angle detected by the angle sensor 27 matches the standing guidance angle (in this example, time point T12 in FIG. 4) (the "No" determination in step S106 in FIG. 3). In this example, the standing guidance time is 1 minute. Note that the standing guidance time may be a time of 10 seconds to 10 minutes (preferably, 30 seconds to 2 minutes). In this example, the control unit 40 controls the air amount changing unit 26 so as to maintain the forward tilt angle detected by the angle sensor 27 at the standing guidance angle from the time when the forward tilt angle detected by the angle sensor 27 matches the standing guidance angle until the standing guidance time elapses. In this example, the period from the time when the forward tilt angle detected by the angle sensor 27 matches the standing guidance angle until the standing guidance time elapses corresponds to the first maintenance period. As a result, the user of the chair 1 changes the posture from the sitting position to the standing position. In other words, the user of the chair 1 stands up from the chair 1.

[0044] Thereafter, at the time when the standing guidance time elapses from the time when the forward tilt angle detected by the angle sensor 27 matches the standing guidance angle (in this example, time point T13 in FIG. 4), the control unit 40 changes the forward tilt angle to the sitting angle (step S107 in FIG. 3). In this example, the control unit 40 controls the air amount changing unit 26 so as to decrease the forward tilt angle detected by the angle sensor 27 at a predetermined decreasing speed. In this example, the magnitude of the decreasing speed is equal to the magnitude of the increasing speed. Note that the magnitude of the decreasing speed may be larger than the magnitude of the increasing speed.

[0045] Then, from the time when the forward tilt angle detected by the angle sensor 27 matches the sitting angle (in this example, time point T14 in FIG. 4), the control unit 40 controls the air amount changing unit 26 so as to maintain the forward tilt angle detected by the angle sensor 27 at the sitting angle. Thereafter, the control unit 40 returns to step S101 in FIG. 3 and repeatedly executes the processes of steps S101 to S107.

[0046] As described above, according to the chair 1 of the first embodiment, it has a seat surface SS on which a user sits. The chair includes a changing unit 20 and a control unit 40. The changing unit 20 changes the forward tilt angle, which is the angle at which the seat surface SS is inclined with respect to the horizontal plane and increases as the position of the rear edge of the seat surface SS in the vertical direction with respect to the front edge of the seat surface SS becomes higher, between a first angle (in this example, the seating angle) and a second angle (in this example, the standing position induction angle) that is larger than the first angle. The control unit 40 controls the changing unit 20 so as to change the forward tilt angle from the first angle to the second angle and maintain the forward tilt angle at the second angle for a predetermined first maintenance period.

[0047] According to this, the forward tilt angle is maintained at the second angle for the first maintenance period. As a result, it becomes difficult for the user to maintain the sitting position. As a result, the user is induced to change the posture to the standing position. Therefore, the time during which the user's posture is maintained in the sitting position can be shortened.

[0048] Furthermore, in the chair 1 of the first embodiment, the second angle is an angle of 35 degrees to 40 degrees.

[0049] By the way, when the forward tilt angle is an angle of 35 degrees to 40 degrees, it becomes difficult for the user to maintain the sitting position. Therefore, according to the chair 1, the user is more surely induced to change the posture to the standing position. As a result, the time during which the user's posture is maintained in the sitting position can be shortened.

[0050] Furthermore, the chair 1 of the first embodiment includes a seat portion 30 having the seat surface SS and a support portion 10 that supports the changing unit 20. The changing unit 20 includes a first flat plate 21 fixed to the support portion 10, a second flat plate 22, and a swinging portion (in this example, the accommodating portion 25 and the air amount changing portion 26). The second flat plate 22 is fixed to the seat portion 30 and is swingably connected to the first flat plate 21 at the front end portion of the first flat plate 21 so that the central axis of swinging extends in the left - right direction of the seat surface SS. The rocking part rocks the second flat plate 22 with respect to the first flat plate 21.

[0051] Incidentally, when the front end of the seat surface SS moves relatively largely in the vertical direction, the user sitting on the seat surface SS often feels uncomfortable. On the other hand, according to the chair 1, the distance by which the front end of the seat surface SS moves in the vertical direction can be shortened as the forward tilt angle changes. Therefore, it is possible to suppress the user sitting on the seat surface SS from feeling uncomfortable.

[0052] Further, according to the chair 1, compared with the case where the second flat plate 22 is connected to be swingable with respect to the first flat plate 21 at a position behind the front end portion of the first flat plate 21, as the forward tilt angle increases, the rear end of the seat surface SS can be increased in the vertical direction. The rising distance can be lengthened. As a result, as the forward tilt angle increases, the user's buttocks can be sufficiently raised in the vertical direction. As a result, it is possible to more surely induce the user to change the posture to the standing position.

[0053] Furthermore, in the chair 1 of the first embodiment, the rocking part includes a housing part 25 that houses air between the second flat plate 22 and the first flat plate 21 and whose volume changes according to the amount of air housed, and the amount of air housed in the housing part 25. And an air amount changing part 26 for changing the amount.

[0054] According to this, it is possible to suppress the occurrence of vibration as the forward tilt angle changes. In addition, it is possible to suppress the sound generated as the forward tilt angle changes. Therefore, it is possible to suppress the user sitting on the seat surface SS from feeling uncomfortable.

[0055] Note that the chair 1 of the first embodiment may maintain the forward tilt angle at the standing position induction angle even after the standing position induction time has elapsed (in this example, the time point T13 in FIG. 4) from the time when the forward tilt angle coincides with the standing position induction angle. In this case, the chair 1 may be configured to change the forward tilt angle to the sitting angle when receiving an end instruction from the user of the chair 1.

[0056] Incidentally, the chair 1 of the first embodiment changes the forward tilt angle by using the pressure of air. Note that the chair 1 of the modified example of the first embodiment may be configured to change the forward tilt angle by using the pressure of a liquid (for example, oil) instead of the pressure of air. In this case, the chair 1 may be provided with a hydraulic cylinder.

[0057] Further, the chair 1 of the first embodiment measures the elapsed time and controls the forward tilt angle based on the measured elapsed time. Note that the chair 1 of the modified example of the first embodiment may control the forward tilt angle based on the biological information of the user of the chair 1 or the operation information of the information processing apparatus used by the user of the chair 1 instead of or in addition to the elapsed time.

[0058] For example, the biological information of the user of the chair 1 is information indicating the drowsiness of the user. In this case, the chair 1 may be configured to detect the drowsiness of the user using a known technique and increase the forward tilt angle when drowsiness is detected. Further, in this case, the chair 1 may be configured to increase the acceleration rate of the increase in the forward tilt angle when drowsiness is detected.

[0059] Also, for example, the operation information of the information processing apparatus used by the user of the chair 1 is information indicating the end of a task (for example, processing corresponding to a predetermined work or business) executed by the information processing apparatus. In this case, the chair 1 may be configured to detect the end of the task executed by the information processing apparatus using a known technique and increase the forward tilt angle when the end of the task is detected.

[0060] <First Modified Example of the First Embodiment> Next, the chair of the first modified example of the first embodiment will be described. The chair of the first modified example of the first embodiment is different from the chair of the first embodiment in that it guides the change of the user's posture over a plurality of times. Hereinafter, the description will focus on the differences. In the description of the first modified example of the first embodiment, those denoted by the same reference numerals as those used in the first embodiment are the same or substantially the same.

[0061] (Operation) An example of the operation of the chair 1 according to the first modification of the first embodiment will be described with reference to FIGS. 5 and 6. In this example, the control unit 40 executes a forward tilt angle control process represented by a flowchart in FIG. 5. The control unit 40 waits until it receives a start instruction input by the user of the chair 1 (the "No" determination in step S101A of FIG. 5). Then, when the start instruction is input by the user of the chair 1, the control unit 40 receives the input start instruction.

[0062] Thereby, the control unit 40 proceeds to step S102A in FIG. 5 and changes the forward tilt angle to the seating angle (step S102A in FIG. 5). In this example, the control unit 40 controls the air volume changing unit 26 so that the forward tilt angle detected by the angle sensor 27 matches the seating angle.

[0063] The seating angle is a forward tilt angle at which the user of the chair 1 can easily maintain the posture on the seat. In this example, the seating angle is 0 degrees. Note that the seating angle may be an angle of -5 degrees to 5 degrees. In this example, the seating angle corresponds to the first angle. Then, the control unit 40 controls the air volume changing unit 26 so as to maintain the forward tilt angle detected by the angle sensor 27 at the seating angle. Thereby, the user of the chair 1 sits on the seat surface SS of the chair 1. In other words, the user of the chair 1 sits on the chair 1.

[0064] Next, the control unit 40 starts measuring the elapsed time (step S103A in FIG. 5). Next, the control unit 40 waits until the first forward tilt start time arrives (the "No" determination in step S104A of FIG. 5). In this example, the first forward tilt start time is the time when a predetermined first waiting time has elapsed after the start instruction is input by the user. In this example, the first waiting time is 30 minutes. Note that the first waiting time may be a time of 10 minutes to 2 hours (preferably 20 minutes to 1 hour).

[0065] Thereafter, when the first forward tilt start point arrives (in this example, time point T21 in FIG. 6), the control unit 40 changes the forward tilt angle to the first standing position induction angle (step S105A in FIG. 5). In this example, the control unit 40 controls the air amount changing unit 26 so as to increase the forward tilt angle detected by the angle sensor 27 at a predetermined first acceleration rate. In this example, the first acceleration rate is 5 degrees per minute. Note that the first acceleration rate may be a rate of 1 degree per minute to 80 degrees per minute (preferably 2 degrees per minute to 10 degrees per minute).

[0066] The control unit 40 controls the air amount changing unit 26 so as to continue increasing the forward tilt angle until the forward tilt angle detected by the angle sensor 27 matches the first standing position induction angle. The first standing position induction angle is larger than the seat angle.

[0067] The first standing position induction angle is a forward tilt angle that causes the user of the chair 1 to recognize that a change in posture is recommended. In other words, the first standing position induction angle is a forward tilt angle that causes the user of the chair 1 to recognize that it is recommended to change the posture from the sitting position to the standing position. In this example, the first standing position induction angle is 15 degrees. Note that the first standing position induction angle may be an angle of 10 degrees to 25 degrees. In this example, the first standing position induction angle corresponds to a third angle that is larger than the first angle and smaller than the second angle.

[0068] Then, the control unit 40 waits until a predetermined first standing position induction time elapses from the time when the forward tilt angle detected by the angle sensor 27 matches the first standing position induction angle (in this example, time point T22 in FIG. 6) ("No" determination in step S106A in FIG. 5). In this example, the first standing position induction time is 1 minute. Note that the first standing position induction time may be a time of 10 seconds to 10 minutes (preferably 30 seconds to 2 minutes).

[0069] In this example, the control unit 40 controls the air volume changing unit 26 so as to maintain the forward tilt angle detected by the angle sensor 27 at the first standing position guiding angle from when the forward tilt angle detected by the angle sensor 27 matches the first standing position guiding angle until the first standing position guiding time elapses. In this example, the period from when the forward tilt angle detected by the angle sensor 27 matches the first standing position guiding angle until the first standing position guiding time elapses corresponds to the second maintaining period. As a result, the user of the chair 1 may change their posture from the sitting position to the standing position. Note that the user of the chair 1 may also maintain their posture in the sitting position.

[0070] After that, the control unit 40 changes the forward tilt angle to the sitting angle at the time when the first standing position guiding time has elapsed (time T23 in FIG. 6 in this example) from the time when the forward tilt angle detected by the angle sensor 27 matches the first standing position guiding angle (step S107A in FIG. 5). In this example, the control unit 40 controls the air volume changing unit 26 so as to decrease the forward tilt angle detected by the angle sensor 27 at a predetermined first decreasing speed. In this example, the magnitude of the first decreasing speed is equal to the magnitude of the first increasing speed. Note that the magnitude of the first decreasing speed may be greater than the magnitude of the first increasing speed.

[0071] Then, the control unit 40 controls the air volume changing unit 26 so as to maintain the forward tilt angle detected by the angle sensor 27 at the sitting angle from the time when the forward tilt angle detected by the angle sensor 27 matches the sitting angle (time T24 in FIG. 6 in this example) until the second forward tilt start time (time T25 in FIG. 6 in this example). In this way, the control unit 40 waits until the second forward tilt start time arrives (the "No" determination in step S108A in FIG. 5). In this example, the second forward tilt start time is the time when a predetermined second waiting time has elapsed after a start instruction is input by the user. The second waiting time is longer than the sum of the first waiting time, the time for changing the forward tilt angle from the sitting angle to the first standing position guiding angle, the first standing position guiding time, and the time for changing the forward tilt angle from the first standing position guiding angle to the sitting angle. In this example, the second waiting time is 1 hour. Note that the second waiting time may be a time of 20 minutes to 4 hours (preferably, 30 minutes to 2 hours).

[0072] After that, when the second forward tilt start time point arrives (in this example, time point T25 in FIG. 6), the control unit 40 changes the forward tilt angle to the second standing position induction angle (step S109A in FIG. 5). In this example, the control unit 40 controls the air amount changing unit 26 so as to increase the forward tilt angle detected by the angle sensor 27 at a predetermined second acceleration rate. In this example, the second acceleration rate is equal to the first acceleration rate. Note that the magnitude of the second acceleration rate may be larger than the magnitude of the first acceleration rate.

[0073] The control unit 40 controls the air amount changing unit 26 so as to continue increasing the forward tilt angle until the forward tilt angle detected by the angle sensor 27 matches the second standing position induction angle. The second standing position induction angle is larger than the seat angle and also larger than the first standing position induction angle.

[0074] The second standing position induction angle is a forward tilt angle at which it is difficult for the user of the chair 1 to maintain the posture in the seat. In other words, the second standing position induction angle is a forward tilt angle that induces (in other words, promotes) the user of the chair 1 to change the posture from the seat to the standing position. In this example, the second standing position induction angle is 35 degrees. Note that the second standing position induction angle may be an angle between 30 degrees and 45 degrees. In this example, the second standing position induction angle corresponds to the second angle.

[0075] Then, the control unit 40 waits until a predetermined second standing position induction time elapses from the time when the forward tilt angle detected by the angle sensor 27 matches the second standing position induction angle (in this example, time point T26 in FIG. 6) (the "No" determination in step S110A in FIG. 5). In this example, the second standing position induction time is equal to the first standing position induction time. Note that the second standing position induction time may be longer than the first standing position induction time. For example, the second standing position induction time may be a time between 10 seconds and 10 minutes.

[0076] In this example, the control unit 40 controls the air volume changing unit 26 so as to maintain the forward tilt angle detected by the angle sensor 27 at the second standing position guiding angle from the time when the forward tilt angle detected by the angle sensor 27 coincides with the second standing position guiding angle until the second standing position guiding time elapses. In this example, the period from the time when the forward tilt angle detected by the angle sensor 27 coincides with the second standing position guiding angle until the second standing position guiding time elapses corresponds to the first maintenance period. As a result, the user of the chair 1 changes their posture from the seated position to the standing position.

[0077] Thereafter, the control unit 40 changes the forward tilt angle to the seated position angle at the time when the second standing position guiding time elapses (time point T27 in FIG. 6 in this example) from the time when the forward tilt angle detected by the angle sensor 27 coincides with the second standing position guiding angle (step S111A in FIG. 5). In this example, the control unit 40 controls the air volume changing unit 26 so as to decrease the forward tilt angle detected by the angle sensor 27 at a predetermined second decreasing speed. In this example, the magnitude of the second decreasing speed is equal to the magnitude of the second increasing speed. Note that the magnitude of the second decreasing speed may be greater than the magnitude of the second increasing speed.

[0078] Then, the control unit 40 controls the air volume changing unit 26 so as to maintain the forward tilt angle detected by the angle sensor 27 at the seated position angle from the time when the forward tilt angle detected by the angle sensor 27 coincides with the seated position angle (time point T28 in FIG. 6 in this example). Thereafter, the control unit 40 returns to step S101A in FIG. 5 and repeatedly executes the processes of steps S101A to S111A.

[0079] As described above, according to the chair 1 of the first modification of the first embodiment, the same operations and effects as those of the chair 1 of the first embodiment are achieved. Furthermore, in the chair 1 according to the first modification of the first embodiment, the control unit 40 changes the forward tilt angle from the first angle (in this example, the seat angle) to a third angle (in this example, the first standing induction angle) that is larger than the first angle and smaller than the second angle (in this example, the second standing induction angle), maintains the forward tilt angle at the third angle for a predetermined second maintenance period, and then changes the forward tilt angle to the second angle and controls the changing unit 20 to maintain the forward tilt angle for a first maintenance period.

[0080] According to this, the forward tilt angle is maintained at the third angle, which is larger than the first angle, for the second maintenance period. Thereby, the user is induced to change the posture to the standing position. Furthermore, even when the user's posture is maintained in the seated position, thereafter, the forward tilt angle is changed to the second angle, which is larger than the third angle, and the forward tilt angle is maintained at the second angle for the first maintenance period. Therefore, the user is more surely induced to change the posture to the standing position. As a result, the time during which the user's posture is maintained in the seated position can be shortened.

[0081] Note that the chair 1 according to the first modification of the first embodiment may maintain the forward tilt angle at the second standing induction angle even after the time when the second standing induction time has elapsed (in this example, the time point T27 in FIG. 6) from the time point when the forward tilt angle coincides with the second standing induction angle. In this case, the chair 1 may be configured to change the forward tilt angle to the seat angle when receiving an end instruction from the user of the chair 1.

[0082] Note that the chair 1 according to the first modification of the first embodiment induces the change of the user's posture twice, but may be configured to induce the change of the user's posture a plurality of times three or more times.

[0083] <Second Modification of the First Embodiment> Next, the chair according to the second modification of the first embodiment will be described. The chair according to the second modification of the first embodiment is different from the chair according to the first modification of the first embodiment in that the forward tilt angle is changed to the second standing position induction angle without changing from the first standing position induction angle to the sitting position angle. Hereinafter, the description will focus on the differences. In the description of the second modification of the first embodiment, those denoted by the same reference numerals as those used in the first modification of the first embodiment are the same or substantially the same.

[0084] (Operation) An example of the operation of the chair 1 according to the second modification of the first embodiment will be described with reference to FIGS. 7 and 8. In this example, the control unit 40 executes the forward tilt angle control process represented by the flowchart in FIG. 7. The forward tilt angle control process in FIG. 7 is different from the forward tilt angle control process in FIG. 5 in that the processes of step S107A and step S108A are deleted.

[0085] Therefore, the control unit 40 changes the forward tilt angle to the first standing position induction angle from the time when the first forward tilt start time point arrives (in this example, the time point T31 in FIG. 8), similar to the first modification of the first embodiment, and from the time when the forward tilt angle coincides with the first standing position induction angle (in this example, the time point T32 in FIG. 8) to the time when the first standing position induction time elapses (in this example, the time point T33 in FIG. 8), the forward tilt angle is maintained at the first standing position induction angle (steps S101A to S106A in FIG. 7).

[0086] Thereafter, the control unit 40 changes the forward tilt angle to the second standing position induction angle at the time when the first standing position induction time elapses (in this example, the time point T33 in FIG. 8) from the time when the forward tilt angle detected by the angle sensor 27 coincides with the first standing position induction angle (step S109A in FIG. 7).

[0087] Thereafter, the control unit 40 maintains the forward tilt angle at the second standing position induction angle from the time when the forward tilt angle coincides with the second standing position induction angle (in this example, the time point T34 in FIG. 8) to the time when the second standing position induction time elapses (in this example, the time point T35 in FIG. 8), similar to the first modification of the first embodiment (step S110A in FIG. 7).

[0088] Thereafter, in the same manner as in the first modification of the first embodiment, when the forward tilt angle matches the second standing position induction angle, the control unit 40 changes the forward tilt angle to the seating angle from the point in time when the second standing position induction time has elapsed (in this example, the point in time T35 in FIG. 8).

[0089] As described above, according to the chair 1 of the second modification of the first embodiment, the same operations and effects as those of the chair 1 of the first modification of the first embodiment are achieved.

[0090] Note that the chair 1 of the second modification of the first embodiment may maintain the forward tilt angle at the second standing position induction angle even after the point in time when the second standing position induction time has elapsed (in this example, the point in time T35 in FIG. 8) from the point in time when the forward tilt angle matches the second standing position induction angle. In this case, the chair 1 may be configured to change the forward tilt angle to the seating angle when it receives an end instruction from the user of the chair 1.

[0091] Note that the chair 1 of the second modification of the first embodiment guides the change of the user's posture twice, but may be configured to guide the change of the user's posture a plurality of times three or more times.

[0092] <Second Embodiment> Next, the chair of the second embodiment will be described. The chair of the second embodiment is different from the chair of the first embodiment in that it detects the posture of the user and controls the forward tilt angle based on the detected posture. Hereinafter, the description will focus on the differences. In the description of the second embodiment, those denoted by the same reference numerals as those used in the first embodiment are the same or substantially the same.

[0093] (Configuration) As shown in FIG. 9, in the chair 1A of the second embodiment, the changing unit 20 includes a pressure sensor 28A in addition to the configuration included in the changing unit 20 of the first embodiment. The pressure sensor 28A detects the load applied to the seat portion 30. In this example, the pressure sensor 28A is fixed to the lower end surface of the second flat plate 22 so as to be sandwiched between the second flat plate 22 and the accommodating portion 25.

[0094] In this example, the fact that the load detected by the pressure sensor 28A is equal to or greater than a predetermined threshold value corresponds to the detection that the posture of the user of the chair 1A is a sitting position, and the fact that the load detected by the pressure sensor 28A is less than the threshold value corresponds to the detection that the posture of the user of the chair 1A is a standing position. In this example, the pressure sensor 28A corresponds to a detection unit that detects the posture of the user of the chair 1A.

[0095] Furthermore, instead of the control unit 40 of the first embodiment, the chair 1A includes a control unit 40A. In this example, the control by the control unit 40A is performed by the control unit 40A transmitting and receiving signals to and from each of the air volume changing unit 26, the angle sensor 27, and the pressure sensor 28A. Note that the detailed description of the functions of the control unit 40A is supplemented by the description of the operation of the chair 1A described later.

[0096] (Operation) An example of the operation of the chair 1A according to the second embodiment will be described with reference to FIGS. 10 and 11. In this example, the control unit 40A executes a forward tilt angle control process represented by a flowchart in FIG. 10. The forward tilt angle control process in FIG. 10 is different from the forward tilt angle control process in FIG. 3 in that the process of step S101 is replaced by the processes of step S1011B and step S1012B.

[0097] In this example, the control unit 40A waits until it detects that the posture of the user of the chair 1A is a sitting position (step S1011B in FIG. 10). When it is detected that the posture of the user of the chair 1A is a sitting position, the control unit 40A, independently of the forward tilt angle control process in FIG. 10, executes a standing position control process represented by a flowchart in FIG. 11. Next, in the forward tilt angle control process, the control unit 40A executes the processes after step S102 in the same manner as in the first embodiment.

[0098] On the one hand, in the standing position control process, the control unit 40A waits until it detects that the posture of the user of the chair 1A is in the standing position (step S201B in FIG. 11). When it is detected that the posture of the user of the chair 1A is in the standing position, the control unit 40A ends the forward tilt angle control process of FIG. 10 that is being executed (step S202B in FIG. 11).

[0099] Next, the control unit 40A changes the forward tilt angle to the seating angle (step S203B in FIG. 11), and independently of the standing position control process of FIG. 11, executes the forward tilt angle control process of FIG. 10 (step S204B in FIG. 11). After that, the control unit 40A ends the standing position control process.

[0100] As described above, according to the chair 1A of the second embodiment, the same operations and effects as those of the chair 1 of the first embodiment are achieved. Furthermore, in the chair 1A of the second embodiment, a detection unit (in this example, the pressure sensor 28A) for detecting the posture of the user of the chair 1A is provided, and the control unit 40A controls the changing unit 20 based on the detected posture.

[0101] According to this, when the posture of the user of the chair 1A changes to the standing position, by changing the forward tilt angle to the first angle (in this example, the seating angle), the user of the chair 1A can easily sit down.

[0102] Note that the chair 1A of the modified example of the second embodiment may be configured to extend the period during which the forward tilt angle is maintained at the second angle (in this example, the standing position induction angle) when the posture of the user of the chair 1A is maintained in the seated position. According to this, it is possible to more surely induce the user of the chair 1A to change the posture to the standing position.

[0103] In addition, the chair 1A according to the modified example of the second embodiment may include an infrared sensor in addition to, or instead of, the pressure sensor 28A, and detect the posture of the user of the chair 1A using infrared rays. Further, the chair 1A according to the modified example of the second embodiment may include a camera in addition to, or instead of, the pressure sensor 28A, and detect the posture of the user of the chair 1A using the image captured by the camera.

[0104] Note that the present invention is not limited to the above-described embodiments. For example, various modifications that can be understood by those skilled in the art may be added to the above-described embodiments without departing from the gist of the present invention.

Explanation of Reference Numerals

[0105] 1, 1A Chair 10 Support part 20 Modifying part 21 First flat plate 22 Second flat plate 23 Connecting part 24 Spacer 25 Accommodating part 26 Air volume changing part 27 Angle sensor 28A Pressure sensor 30 Seat part 40, 40A Control part SS Seat surface

Claims

1. A chair having a seat surface on which a user sits, wherein the seat surface has a forward tilt angle which is an angle of inclination with respect to a horizontal plane and increases as the vertical position of the rear edge of the seat surface relative to the front edge of the seat surface increases, and the forward tilt angle is between a first angle of -5 degrees to 5 degrees which is an angle at which the user can easily maintain the sitting posture, and a second angle of 35 degrees to 40 degrees which is larger than the first angle and at which the user has difficulty maintaining the sitting posture, and a changing portion for changing between them; a control portion for controlling the changing portion such that, when a predetermined waiting time has elapsed after a start instruction is input by the user, the forward tilt angle is changed from the first angle to the second angle, and the forward tilt angle is maintained at the second angle for a predetermined first maintenance period; A chair comprising the above.

2. The chair according to claim 1, wherein the control portion changes the forward tilt angle from the first angle to a third angle which is larger than the first angle and smaller than the second angle, maintains the forward tilt angle at the third angle for a predetermined second maintenance period, and then changes the forward tilt angle to the second angle and controls the changing portion to maintain the forward tilt angle for the first maintenance period.

3. The chair according to claim 1 or claim 2, wherein biological information of the user is detected, and the control portion controls the changing portion based on the detected biological information, wherein the biological information is information indicating the user's drowsiness.

4. The chair according to any one of claims 1 to 3, comprising a seat portion having the seat surface, and a support portion for supporting the changing portion, wherein the changing portion comprises a first flat plate fixed to the support portion, a second flat plate to which the seat portion is fixed and which is swingably connected to the first flat plate at the front end portion of the first flat plate such that a central axis of swing extends in the left-right direction of the seat surface, and a swinging portion for swinging the second flat plate with respect to the first flat plate. A chair comprising the above.

5. The chair according to any one of claims 1 to 4, wherein operation information of an information processing apparatus used by the user is detected, and the control portion controls the changing portion based on the detected operation information, wherein the operation information is information indicating the end of a task executed by the information processing apparatus.

6. A forward tilt angle changing device for changing a forward tilt angle which is an angle at which a seating surface on which a user sits is inclined with respect to a horizontal plane and which increases as the position of the rear edge of the seating surface in the vertical direction with respect to the front edge of the seating surface becomes higher, a changing unit that changes the forward tilt angle between a first angle of -5 degrees to 5 degrees, which is an angle at which the user can easily maintain their posture in the seat, and a second angle of 35 degrees to 40 degrees, which is larger than the first angle and at which the user has difficulty maintaining their posture in the seat; a control unit that controls the changing unit to change the forward tilt angle from the first angle to the second angle and maintain the forward tilt angle at the second angle for a predetermined first maintenance period when a predetermined waiting time has elapsed after a start instruction is input by the user; A forward tilt angle changing device comprising: **Claim 7** A forward tilt angle changing method for changing a forward tilt angle which is an angle at which a seating surface on which a user sits is inclined with respect to a horizontal plane and which increases as the position of the rear edge of the seating surface in the vertical direction with respect to the front edge of the seating surface becomes higher, when a predetermined waiting time has elapsed after a start instruction is input by the user, changing the forward tilt angle from a first angle of -5 degrees to 5 degrees, which is an angle at which the user can easily maintain their posture in the seat, to a second angle of 35 degrees to 40 degrees, which is larger than the first angle and at which the user has difficulty maintaining their posture in the seat, and maintaining the forward tilt angle at the second angle for a predetermined first maintenance period; A forward tilt angle changing method comprising the above.

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