Load compensation device

Abstract

[Problem] To provide a load compensation device having higher convenience. [Solution] The load compensation device 1 comprises a support part 10, a first link 20, a wire 60, and a torque application unit 80. With respect to the center of rotation that serves as a fulcrum point in the support part 10, the weight of an object that is a load is applied to one end side of the first link 20, and a load-compensating force is input to the other end side of the first link 20. The wire 60 is looped around the position of the fulcrum point of the first link 20 and the position where the load-compensating force is input, extends vertically downward from the position of the fulcrum point of the first link 20 and the position where the load-compensating force is input, and has one fixed end. The torque application unit 80 applies a rotational torque for winding the other end of the wire 60.

Description

[Technical Field]

[0001] The present invention relates to a load compensation device that generates a balancing force for a load. [Background technology]

[0002] In recent years, manual labor for carrying heavy objects has become common in a variety of situations, and support devices are being used to reduce the burden on the workers. However, most of these devices use actuators, which require a power source, limiting the locations where they can be used and reducing safety when working collaboratively with humans. Therefore, a mechanical load compensation device that does not use actuators is considered to be effective. Here, Patent Document 1 discloses a compensation weight switching type load compensation device as a mechanical load compensation device that does not use an actuator. The compensation weight switching load compensation device described in Patent Document 1 adds a second spring and a switching mechanism made up of gears to the structure of the mechanical weight compensation mechanism so that it can also handle the addition of a new load, making it possible to compensate for two load states: the arm's own weight compensation state, and when a set load is added. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-098821 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a load compensation device is used to support transportation work, etc., it is required to be able to adjust the load to be compensated at any height. In contrast, with conventional load compensation devices, it is necessary to adjust the load to be compensated for with the load compensation device in a predetermined reference position, and there is room for improvement in terms of convenience.

[0005] An object of the present invention is to realize a load compensation device that is more convenient to use. [Means for solving the problem]

[0006] In order to solve the above problem, a load compensation device according to one aspect of the present invention comprises: A support; a first link member, one end of which is subjected to the weight of a load and the other end of which is input with a force for load compensation, with respect to a rotation center serving as a fulcrum in the support; a first cable member that is connected between the position of the fulcrum of the first link member and the position where the force for load compensation is input, extends vertically downward from the position of the fulcrum of the first link member and the position where the force for load compensation is input, and has one end fixed; a torque applying means for applying a rotational torque for winding up the other end of the first cable member; Equipped with. [Effects of the Invention]

[0007] According to the present invention, a load compensation device with higher convenience can be realized. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing the overall configuration of a load compensation device 1 according to a first embodiment. [Figure 2] FIG. 10 is a schematic diagram showing the overall configuration of a load compensation device 1 according to a second embodiment. [Figure 3] 2 is a schematic diagram showing the overall configuration of the load compensation device 1, with a portion of the front side member being partially see-through. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [First embodiment] [composition] Fig. 1 is a schematic diagram showing the overall configuration of a load compensation device 1 according to the first embodiment. Note that Fig. 1 schematically shows the link structure of the load compensation device 1. In FIG. 1, the load compensation device 1 includes a support portion 10, a first link 20, a second link 30, a third link 40, pulleys 50a and 50b, a wire 60, a wire winding portion 70, and a torque applying portion 80.

[0010] 1, g represents the acceleration of gravity, M represents the mass that applies the load, m represents the mass of the first link 20, L represents the distance from the center of rotation O of the first link 20 to the point at which the load acts, l represents the distance from the center of rotation O of the first link 20 to the center of gravity, p represents the distance from the center of rotation O of the first link 20 to the point at which the tension of the wire 60 acts, and θ represents the angle of the first link 20 from the horizontal direction. Also, α represents the gear ratio (gain) of the transmission 82, which will be described later, and αF represents the output of the transmission 82.

[0011] The support unit 10 is a base member that supports the entire load compensation device 1, and includes a support column 11 that supports the first link 20 rotatably about the rotation axis R1, and a sliding mechanism 12 that supports the second link 30 slidably in the vertical and horizontal directions. The sliding mechanism 12 includes a linear guide 12a that supports the second link 30 slidably in the vertical direction, and a linear guide 12b that supports the linear guide 12a slidably in the horizontal direction.

[0012] The weight (load) of a load object acts on one end of the first link 20, and the other end of the first link 20 is provided with a pulley 50b rotatable about a rotation axis R2. The first link 20 is also rotatably supported at its center by the rotation axis R1 of the support part 10.

[0013] One end of the second link 30 is rotatably supported on the rotation axis R2 of the first link 20. The second link 30 is also supported on the linear guide 12a of the sliding mechanism 12 so as to be slidable in the vertical direction. The other end of the second link 30 supports one end of the third link 40 so as to be rotatable on the rotation axis R3.

[0014] One end of the third link 40 is rotatably supported by the rotation axis R3 of the second link 30. The other end of the third link 40 is rotatably supported by the support 10 at the rotation axis R4. The distance between the rotation axis R1 and the rotation axis R4 is the same as the length of the second link 30. That is, the portion of the first link 20 from the rotation axis R1 to the rotation axis R2, and the portions of the second link 30, the third link 40, and the support 10 from the rotation axis R1 to the rotation axis R4 form a parallel link. Therefore, when the angle of the first link 20 with respect to the support 10 changes, the second link 30 moves vertically and horizontally with respect to the support 10 due to the action of the sliding mechanism 12 while maintaining its posture along the vertical direction.

[0015] The pulley 50a is installed at the tip of the support column 11 of the support part 10 so as to be rotatable about a rotation axis R1 to which the first link 20 is rotatably connected. The pulley 50b is installed so as to be rotatable about a rotation axis R2 to which the first link 20 and the second link 30 are connected.

[0016] The wire 60 is wound around the pulley 50b, and one end of the wire 60 is installed at a position vertically below the pulley 50b in the linear guide 12b of the sliding mechanism 12. Therefore, one end of the wire 60 is maintained in a state where it always extends vertically downward from the pulley 50b. The wire 60 is also wound from the pulley 50b to the pulley 50a, and the other end is wound around the wire winding section 70.

[0017] The wire winding unit 70 winds and unwinds the wire 60 to achieve the rotational torque applied by the torque applying unit 80. As a result, the tension applied to the wire 60 is controlled by the rotational torque applied by the torque applying unit 80, and a force for load compensation (load compensation force) is generated. The wire winding unit 70 is installed vertically below the pulley 50a so that the other end of the wire 60 wound around the pulley 50a extends vertically downward and is wound. One end and the other end of the wire 60 extend vertically downward from the portions wound around the pulleys 50a and 50b, and the portion between the pulleys 50a and 50b is parallel to the first link 20. Therefore, of the forces applied from the wire 60 to the pulleys 50a and 50b, the forces parallel to the first link 20 cancel each other out, and only the vertically downward force acts. That is, a vertical downward force acts on the other end side (pulley 50b) of the first link 20 by the wire 60, and load compensation is achieved by applying a rotational torque to the wire winding section 70 so that this force balances the weight of the first link 20 and the load applied to one end side.

[0018] The torque applying unit 80 applies a rotational torque to the wire winding unit 70 to wind the wire 60 . Specifically, the torque applying unit 80 includes a constant torque spring 81 and a transmission 82.

[0019] The constant torque spring 81 is formed of, for example, a contact type spiral spring, and outputs a constant rotational torque. The transmission 82 is coupled to the constant torque spring 81 by a gear, and receives the constant rotational torque output by the constant torque spring 81. The transmission 82 is equipped with a stepless or multi-stage speed change mechanism, and applies a gain to the input constant rotational torque and outputs it to the wire winding unit 70. By setting the gain applied by the transmission 82 to a desired value, the rotational torque applied to the wire winding unit 70 can be changed, and therefore the load compensated by the load compensation device 1 can be adjusted.

[0020] [Load compensation principle] In the above-described configuration, the condition for load compensation in the load compensation device 1 is that the sum of the rotational torque due to the load Mg and the rotational torque due to the weight mg of the first link 20 is balanced with the rotational torque due to the output αF of the transmission 82. That is, it is necessary to set α so that the following equation (1) holds. M×g×L×cosθ+m×g×l×cosθ=α×F×p×cosθ (1)

[0021] Here, the output αF of the transmission 82 is determined by the rotational torque τ output by the constant torque spring 81 and the drum radius r of the wire winding section 70, so when equation (1) is solved for α, the following equation (2) is obtained. α=(m×l+M×L)×g×r / (p×τ) (2) In equation (2), the angle θ of the second link 20 with respect to the horizontal direction is not included in the factors that determine α. That is, the formula (2) holds true regardless of the rotation angle of the first link 20. Therefore, when compensating for an arbitrary load in the load compensation device 1, the gear ratio α is calculated from equation (2) according to the load to be compensated for, and the gear ratio of the transmission 82 is set to α, thereby realizing load compensation in any posture.

[0022] [Effect] In the load compensation device 1 having the above-described configuration, once the load Mg acting on the first link 20 is determined, the weight of the first link 20 is known, and therefore the gear ratio (gain) α to be set in the transmission 82 can be calculated from equation (2). Then, when the worker sets the gear ratio α of the transmission 82 to the calculated value, the output αF of the transmission 82 is applied to the wire 60, and this output αF is transmitted by the wire 60, generating a rotational torque at the position of the pulley 50b that rotates the first link 20 in the direction opposite to the direction of the load. The rotational torque due to the output αF is balanced with the rotational torque around point O that is generated by the weight of the first link 20 and the load acting on the object. Note that equation (2) holds true for any rotation angle of the first link 20, and therefore load compensation can be achieved in any posture.

[0023] Here, it is assumed that the load acting on the first link 20 in the load compensation device 1 changes to M'g. At this time, a new speed change ratio (gain) α' corresponding to the load M'g is calculated according to equation (2), and the worker sets the speed change ratio (gain) of the transmission 82 to the calculated value α'. As a result, the rotational torque due to the output α'F of the transmission 82 is balanced with the rotational torque around point O generated by the weight of the first link 20 and the new load acting on the object, and load compensation can be achieved in response to changes in the load to be compensated for. That is, it is possible to realize a load compensation device 1 that is more convenient to use.

[0024] [Second embodiment] Next, a second embodiment of the present invention will be described. In the first embodiment, the load compensation device 1 having a configuration in which the load acting on the first link 20 is compensated for by the tension transmitted from the torque application unit 80 to the wire 60 has been described. In response to this, it is possible to connect links on which loads act, and to configure the loads input to each link to be compensated for by tension transmitted from torque application unit 80 to wire 60. That is, in a multi-joint mechanism in which multiple links are connected, it is possible to compensate for the load acting on one end of each link by the tension of the wire at the other end. Hereinafter, the configuration of a device that performs load compensation for each link will be described, taking as an example a case where the first link 20 in the first embodiment has a configuration in which two links are connected in series.

[0025] [composition] FIG. 2 is a schematic diagram showing the overall configuration of a load compensation device 1 according to the second embodiment. 3 is a schematic view showing the overall configuration, with a portion of the front side member of the load compensation device 1 in perspective view. Note that in FIGS. 2 and 3, the link structure of the load compensation device 1 is shown in schematic form. 2 and 3, the load compensation device 1 includes a support unit 110, a first link 120, a second link 130, a third link 140, a fourth link 150, a fifth link 160, a sixth link 170, a seventh link 180, an eighth link 190, pulleys 200a to 200e, wires 210a to 210c, wire winding units 220a and 220b, a torque applying unit 230, and a carrier S. In the load compensation device 1 of the second embodiment, the sixth link 170, the seventh link 180, the eighth link 190, the pulley 200b, the wire 210b, and the wire winding unit 220b are arranged on the rear side (the back side of the page) of the support unit 110, and therefore in FIG. 3, the members on the front side are appropriately made transparent to visualize the members necessary for explanation.

[0026] 2 and 3, g represents the acceleration of gravity, M represents the mass applying the load, m1 represents the mass of the first link 120, m2 represents the mass of the fourth link 150, L1 represents the distance from the center of rotation O1 of the first link 120 to the point of load application, L2 represents the distance from the center of rotation O2 of the fourth link 150 to the point of load application, l1 represents the distance from the center of rotation O1 of the first link 120 to the center of gravity, l2 represents the distance from the center of rotation O2 of the fourth link 150 to the center of gravity, p1 represents the distance from the center of rotation O1 of the first link 120 to the point of application of the tension of the wire 60, p2 represents the distance from the center of rotation O1 of the sixth link 170 to the point of application of the tension of the wire 210b, θ1 represents the angle of the first link 120 from the horizontal direction, and θ2 represents the angle of the fourth link 150 from the horizontal direction. Furthermore, α1 represents the gear ratio (gain) of transmission 232a, which will be described later, α1·F1 represents the output of transmission 232a, α2 represents the gear ratio (gain) of transmission 232b, which will be described later, and α2·F2 represents the output of transmission 232b, which will be described later.

[0027] The support unit 110 is a base member that supports the entire load compensation device 1, and includes a support column 111 that rotatably supports the first link 120 about the rotation axis R1, a sliding mechanism 112 that supports the second link 130 so that it can slide in the vertical and horizontal directions, and a sliding mechanism 113 that supports the seventh link 180 so that it can slide in the vertical and horizontal directions. The sliding mechanism 112 includes a linear guide 112a that supports the second link 130 so that it can slide in the vertical direction, and a linear guide 112b that supports the linear guide 112a so that it can slide in the horizontal direction. The sliding mechanism 113 includes a linear guide 113a that supports the seventh link 180 so that it can slide in the vertical direction, and a linear guide 113b that supports the linear guide 113a so that it can slide in the horizontal direction.

[0028] The first link 120 is configured as a parallel link and includes an upper link member 120A and a lower link member 120B. One end of the upper link member 120A of the first link 120 bears the weight (load) of an object acting as a load, and the other end of the first link 120 includes a pulley 200b rotatable about a rotation axis R2. The upper link member 120A is rotatably supported at its center by the rotation axis R1 of the support 110. The lower link member 120B of the first link 120 bears the weight (load) of an object acting as a load on one end, and the other end of the lower link member 120B of the first link 120 is rotatably supported by the support 110 about a rotation axis R5.

[0029] One end of the second link 130 is rotatably supported on the rotation axis R2 of the first link 120. The second link 130 is also supported on the linear guide 112a of the sliding mechanism 112 so as to be slidable in the vertical direction. The other end of the second link 130 supports one end of the third link 140 so as to be rotatable on the rotation axis R3.

[0030] One end of the third link 140 is rotatably supported by the rotation axis R3 of the second link 130. The other end of the third link 140 is rotatably supported by the support 110 at the rotation axis R4. The distance between the rotation axis R1 and the rotation axis R4 is the same as the length of the second link 130. That is, the portion of the first link 120 from the rotation axis R1 to the rotation axis R2, the second link 130, the third link 140, and the portion of the support 110 from the rotation axis R1 to the rotation axis R4 form a parallel link. Therefore, when the angle of the first link 120 with respect to the support 110 changes, the second link 130 moves vertically and horizontally with respect to the support 110 due to the action of the sliding mechanism 112 while maintaining its posture along the vertical direction.

[0031] The fourth link 150 is configured as a parallel link and includes an upper link member 150A and a lower link member 150B. The weight (load) of a load object acts on one end of the upper link member 150A of the fourth link 150, and the other end is rotatably supported by the upper link member 120A of the first link 120 on a rotation axis R6. The weight (load) of a load object acts on one end of the lower link member 150B of the fourth link 150, and the other end is rotatably supported by the lower link member 120B of the first link 120 on a rotation axis R7.

[0032] The fifth link 160 rotatably supports the upper link member 120A of the first link 120 and the upper link member 150A of the fourth link 150 on a rotation axis R6, and also rotatably supports the lower link member 120B of the first link 120 and the lower link member 150B of the fourth link 150 on a rotation axis R7.

[0033] The sixth link 170 has one end rotatably supported by the support portion 110 on a rotation axis R1, and supports the seventh link 180 on the other end side rotatably on a rotation axis R8. One end of the seventh link 180 is rotatably supported by the rotation axis R8 of the sixth link 170. The seventh link 180 is also supported by the linear guide 113a of the sliding mechanism 113 so as to be slidable in the vertical direction. The other end of the seventh link 180 supports one end of the eighth link 190 so as to be rotatable about the rotation axis R9.

[0034] The eighth link 190 has one end rotatably supported by the rotation axis R9 of the seventh link 180, and the other end rotatably supported by the rotation axis R4 of the support portion 110.

[0035] The pulley 200a is installed at the tip of the support column 111 of the support 110 so as to be rotatable about a rotation axis R1 to which the first link 120 is rotatably connected. The pulley 200b is installed so as to be rotatable about a rotation axis R2 to which the first link 120 and the second link 130 are connected.

[0036] The pulley 200c is rotatably mounted on a rotation axis R6, and rotates integrally with the upper link member 150A of the fourth link 150. The pulley 200d is installed at the tip of the support column 111 of the support 110 so as to be rotatable about a rotation axis R1, and rotates integrally with the sixth link 170. A wire 210c for torque transmission is wound around the pulley 200c and the pulley 200d, and connects the upper link member 150A of the fourth link 150 and the sixth link 170 together. The pulley 200e is installed to be rotatable about a rotation axis R8 to which the sixth link 170 and the seventh link 180 are connected.

[0037] Wire 210a is wound around pulley 200b, and one end is installed at a position vertically below pulley 200b on linear guide 112b of sliding mechanism 112. Therefore, one end of wire 210a is maintained in a state where it always extends vertically downward from pulley 200b. Wire 210a is also wound from pulley 200b to pulley 200a, and the other end is wound around wire winding section 220a.

[0038] Wire 210b is wound around pulley 200e, and one end is installed at a position vertically below pulley 200e on linear guide 113b of sliding mechanism 113. Therefore, one end of wire 210b is maintained in a state where it always extends vertically downward from pulley 200e. Wire 210b is also wound from pulley 200e around pulley 200d, and the other end is wound around wire winding section 220b.

[0039] The wire 210c is wound around the pulleys 200c and 200d, and connects the upper link member 150A of the fourth link 150 with the sixth link 170. That is, the wire 210c transmits rotational torque between the upper link member 150A of the fourth link 150 and the sixth link 170.

[0040] The wire winding unit 220a winds and unwinds the wire 210a so as to achieve the rotational torque applied by the torque application unit 230. As a result, the tension applied to the wire 210a is controlled by the rotational torque applied by the torque application unit 230, and a force for load compensation (load compensation force) is generated in the first link 120. The wire winding unit 220a is installed vertically below the pulley 200a so that the other end of the wire 210a wound around the pulley 200a extends vertically downward and is wound up. One end side and the other end side of the wire 210a extend vertically downward from the portion wound around the pulleys 200a and 200b, and the portion between the pulleys 200a and 200b is parallel to the first link 120. Therefore, of the forces applied from wire 210a to pulleys 200a and 200b, the forces parallel to first link 120 cancel each other out, and only a vertically downward force acts. That is, a vertically downward force acts on the other end side (pulley 200b) of first link 120 by wire 210a, and a rotational torque is applied to wire winding portion 220a so that this force balances the weight of first link 120 and the load applied to one end side, thereby achieving load compensation in first link 120.

[0041] The wire winding unit 220b winds and unwinds the wire 210b so as to achieve the rotational torque applied by the torque application unit 230. As a result, the tension applied to the wire 210b is controlled by the rotational torque applied by the torque application unit 230, and a force for load compensation (load compensation force) is generated in the fourth link 150. The wire winding unit 220b is installed vertically below the pulley 200d so that the other end of the wire 210b wound around the pulley 200d extends vertically downward and is wound up. One end and the other end of the wire 210b extend vertically downward from the portions wound around the pulleys 200d and 200e, and the portion between the pulleys 200d and 200e is parallel to the sixth link 170. Therefore, of the forces applied from wire 210b to pulleys 200d and 200e, the forces parallel to sixth link 170 cancel each other out, and only a vertically downward force acts. That is, a vertically downward force acts on the other end side (pulley 200e) of sixth link 170 via wire 210b, and this force is transmitted as a rotational torque of pulley 200c via wire 210c. By applying a rotational torque to wire winding portion 220b so that the force (rotational torque) transmitted by wire 210c balances the weight of fourth link 150 and the load applied to one end side, load compensation in fourth link 150 is realized.

[0042] The torque applying unit 230 applies rotational torque to the wire winding units 220a and 220b to wind the wires 210a and 210b. In this embodiment, the torque applying unit 230 is configured to be able to apply different rotational torques to the wire winding units 220a and 220b, respectively. As an example, the torque applying unit 230 may include a torque applying mechanism for the wire winding unit 220a and a torque applying mechanism for the wire winding unit 220b, respectively.

[0043] That is, the torque applying section 230 includes a constant torque spring 231a and a speed changer 232a as a torque applying mechanism for the wire winding section 220a. The constant torque spring 231a is configured by, for example, a contact type spiral spring, and outputs a constant rotational torque. The transmission 232a is coupled to the constant torque spring 231a via a gear, and receives the constant rotational torque output by the constant torque spring 231a. The transmission 232a has a stepless or multi-stage speed change mechanism, and applies a gain to the input constant rotational torque and outputs it to the wire winding unit 220a. By setting the gain applied by the transmission 232a to a desired value, the rotational torque applied to the wire winding unit 220a can be changed, and the load compensated in the first link 120 can be adjusted.

[0044] The torque applying section 230 also includes a constant torque spring 231b and a speed changer 232b as a torque applying mechanism for the wire winding section 220b. The constant torque spring 231b is configured by, for example, a contact type spiral spring or the like, and outputs a constant rotational torque. The transmission 232b is coupled to the constant torque spring 231b via a gear, and receives the constant rotational torque output by the constant torque spring 231b. The transmission 232b has a stepless or multi-stage speed change mechanism, and applies a gain to the input constant rotational torque and outputs it to the wire winding unit 220b. By setting the gain applied by the transmission 232b to a desired value, the rotational torque applied to the wire winding unit 220b can be changed, and the load compensated in the fourth link 150 can be adjusted.

[0045] An object to be subjected to load compensation by the load compensation device 1 is placed on the loading platform S. The loading platform S also rotatably supports the upper link member 150A and the lower link member 150B of the fourth link 150, thereby functioning as one link of the parallel linkages.

[0046] In the above-described configuration, load compensation in the first link 120 and load compensation in the fourth link 150 are performed independently, and the load compensated in the first link 120 includes the weight of the fourth link 150 itself and the load due to the object. The principles of load compensation in the first link 120 and the fourth link 150 are the same as those in the first embodiment.

[0047] That is, in this embodiment, the speed ratio α1 used for load compensation of the first link 120 is expressed by the following equation (3), where the rotational torque output by the constant torque spring 231a is τ1 and the drum radius of the wire winding portion 220a is r1. α1=(m1×l1+(m2+M)×L1)×g×r1 / (p1×τ1) (3)

[0048] Similarly, in this embodiment, the speed ratio α2 used for load compensation of the fourth link 150 is expressed by the following equation (4), where the rotational torque output by the constant torque spring 231b is τ2 and the drum radius of the wire winding portion 220b is r2. α2=(m2×l2+M×L2)×g×r2 / (p2×τ2) (4)

[0049] [Effect] In the load compensation device 1 having the above-described configuration, once the load Mg acting on the fourth link 150 is determined, the weights of the first link 120 and the fourth link 150 are known, and therefore the gear ratios (gains) α1 and α2 to be set for the transmissions 232a and 232b, respectively, can be calculated using equations (3) and (4). Then, when the operator sets the gear ratio α1 in the transmission 232a to the calculated value, the output α1·F1 of the transmission 232a is applied to the wire 210a, and this output α1·F1 is transmitted by the wire 210a, generating a rotational torque at the position of the pulley 200b that rotates the first link 120 in the direction opposite to the direction of the load. The rotational torque due to the output α1·F1 is balanced with the rotational torque about point O1 that is generated by the weight of the first link 120, the weight of the fourth link 150, and the load acting from the object. Note that equation (3) holds true for any rotation angle of the first link 120, and therefore load compensation is realized in any posture.

[0050] Similarly, when the operator sets the gear ratio α2 of the transmission 232b to the calculated value, the output α2·F2 of the transmission 232b is applied to the wire 210b, and this output α2·F2 is transmitted by the wire 210b, generating a rotational torque at the position of the pulley 200e that rotates the sixth link 170 in the direction opposite to the direction of the load. This rotational torque is transmitted via the wire 210c as the rotational torque of the pulley 200c (i.e., the fourth link 150). The rotational torque due to the output α2·F2 is balanced with the rotational torque around point O2 that is generated by the weight of the fourth link 150 and the load acting on the object. Note that equation (4) holds true for any rotation angle of the fourth link 150, and therefore load compensation is realized in any posture.

[0051] Here, it is assumed that the load acting on the fourth link 150 in the load compensation device 1 changes to M'g. At this time, a new speed change ratio (gain) α1' corresponding to the load M'g is calculated according to equation (3), and the worker sets the speed change ratio (gain) of the transmission 232a to the calculated value α1'. Similarly, a new speed change ratio (gain) α2' corresponding to the load M'g is calculated according to equation (4), and the worker sets the speed change ratio (gain) of the transmission 232b to the calculated value α2'.

[0052] As a result, the rotational torque due to the output α1'F1 of the transmission 232a is balanced with the rotational torque around point O1 generated by the weight of the first link 120, the weight of the fourth link 150, and the load acting on the object, and load compensation can be achieved in the first link 120 in response to changes in the load to be compensated. Furthermore, the rotational torque due to the output α2'F2 of the transmission 232b is balanced with the rotational torque around point O2 generated by the weight of the fourth link 150 and the load acting on the object, and load compensation can be achieved in the fourth link 150 in response to changes in the load to be compensated for. That is, it is possible to realize a load compensation device 1 that is more convenient to use.

[0053] As described above, the load compensation device 1 according to the present invention includes the support portion 10 (110), the first link 20 (120), the wire 60 (210a), and the torque applying portion 80 (230). The weight of the load object acts on one end of the first link 20 (120) with respect to the center of rotation O, which serves as a fulcrum at the support part 10 (110), and a force for load compensation is input to the other end. The wire 60 (210a) is looped between the position of the fulcrum of the first link 20 (120) and the position where the force for load compensation is input, extends vertically downward from the position of the fulcrum of the first link 20 (120) and the position where the force for load compensation is input, and has one end fixed. The torque applying unit 80 (230) applies a rotational torque for winding up the other end of the wire 60 (210a). This allows a force that balances the load acting on one end of the first link 20 (120) to be applied by a rotational torque from the torque application unit 80 (230) that is input to the other end of the first link 20 (120) via the wire 60 (210a). Therefore, it is possible to realize a load compensation device 1 that is more convenient to use.

[0054] The first link 20 (120) has one end on which the weight of an object acting as a load acts, and has the pulley 50b (200b) on the other end. The support portion 10 (110) rotatably supports the first link 20 (120) between one end and the other end on a rotation axis R1 which serves as the rotation center O, and is equipped with a pulley 50a (200a) installed coaxially with the rotation axis R1. The support section 10 (110) is also provided with a wire winding section 70 that is installed vertically below the pulley 50a (200a) and winds up the wire 60 (210a) with a set rotational torque. One end of the wire 60 (210a) is placed vertically below the pulley 50b (200b) of the first link 20 (120), and the wire 60 (210a) is wound around the pulley 50a (200a) and the pulley 50b (200b), with the other end being wound around the wire winding section 70 (220a). The torque applying unit 80 (230) also applies a rotational torque to the wire winding unit 70 (220a) to wind the wire 60 (210a). This allows the rotational torque from the torque applying unit 80 (230) to be adjusted to the rotational torque set by the wire winding unit 70 (220a). The adjusted rotational torque then achieves balance with the load acting on one end of the first link 20 (120). Therefore, it is possible to realize a load compensation device 1 that is more convenient to use.

[0055] The torque applying section 80 (230) includes a constant torque spring 81 (231a, 231b) and a transmission 82 (232a, 232b). The constant torque spring 81 (231a, 231b) outputs a constant rotational torque. The transmission 82 (232a, 232b) changes and outputs the rotational torque output by the constant torque spring 81 (231a, 231b). This makes it possible to flexibly adjust the output of rotational torque with a simple configuration.

[0056] The load compensation device 1 also includes a first link 120 (upper link member 120A and lower link member 120B), a fourth link 150 (upper link member 150A and lower link member 150B), a sixth link 170, wires 210b, 210c, a wire winding portion 220b, and a torque applying portion 230. The fourth link 150 (upper link member 150A and lower link member 150B) has one end on which the weight of a load object acts, and the other end is rotatably supported on one end side of the first link 120 (upper link member 120A and lower link member 120B) by rotation axes R6 and R7, and is equipped with a pulley 200c installed coaxially with the rotation axis R6. The pulley 200d is supported by the support portion 110 so as to be rotatable about a rotation axis R1. The sixth link 170 has one end connected to a pulley 200d and the other end provided with a pulley 200e. Wire 210c is wound around pulley 200c and pulley 200d, maintaining the fourth link 150 (upper link member 150A) and the sixth link 170 parallel to each other, and transmitting the rotational torque of the fourth link 150 (upper link member 150A) around rotation axis R6 and the rotational torque of the sixth link 170 around rotation axis R1. One end of the wire 210b is placed vertically below the pulley 200e of the sixth link 170, and the wire 210b is wound around the pulleys 200d and 200e. The wire winding section 220b is installed vertically below the pulley 200d and winds the other end of the wire 210b with a set rotational torque. The torque applying unit 230 applies a rotational torque to the wire winding unit 220b to wind the wire 210b. This makes it possible to variably compensate for the load to be compensated for in each of the serially connected links, thereby realizing a load compensation device 1 with higher convenience.

[0057] In the above embodiment, an example has been described in which an object is placed on the loading platform S, but the object for which load compensation according to the present invention is performed is not limited to the case in which an object is placed on the loading platform S. In other words, the present invention can be applied to a system in which the components or load at the tip are replaceable by being detachable or fastened with screws, etc. (for example, a manual crossing barrier on which various types of crossing bars can be installed, etc.). Furthermore, the present invention has a configuration that allows the load to be compensated to be appropriately adjusted without requiring a power source, and therefore can be used in a wide range of situations. For example, the present invention can be applied to palletizing work in agricultural work, loading work onto truck beds, cargo handling work, assistance with getting on and off vehicles for the disabled, or chairs that assist standing up. Furthermore, as long as it performs substantially the same function as the link structure of the load compensation device 1 shown in the above embodiment, it is possible to divide the elastic member into multiple parts and install it, or to divide one link or member such as the support part 10, 110 into multiple parts and install it.

[0058] The above embodiment shows an example of application of the present invention and does not limit the technical scope of the present invention. In other words, the present invention can be modified in various ways, such as by omission or substitution, without departing from the gist of the present invention, and various embodiments other than the above embodiment can be adopted. The various embodiments and modifications that the present invention can adopt are included in the scope of the invention described in the claims and their equivalents. [Explanation of symbols]

[0059] 1 load compensation device, 10,110 support part, 11,111 support part, 12,112,113 sliding mechanism, 12a,12b,112a,112b,113a,113b linear guide, 20,120 first link, 30,130 second link, 40,140 third link, 50a,50b,200a-200e pulley, 60,210a-210c wire, 70,220a,220b wire winding part, 80,230 torque applying part, 81,231a,231b constant torque spring, 82,232a,232b transmission, S loading platform, 150 fourth link, 160 fifth link, 170 sixth link, 180 seventh link, 190 8th link, 120A, 150A upper link members, 120B, 150B lower link members, R1~R9 rotation axis

Claims

1. A support; a first link member, one end of which is subjected to the weight of a load and the other end of which is input with a force for compensating for the load, with respect to a rotation center serving as a fulcrum in the support; a first cable member that is connected between the position of the fulcrum of the first link member and the position where the force for load compensation is input, extends vertically downward from the position of the fulcrum of the first link member and the position where the force for load compensation is input, and has one end fixed; a torque applying means for applying a rotational torque for winding up the other end of the first cable member; Equipped with A load compensation device, characterized in that the first cable member is wound around the first link member around the fulcrum without applying any rotational torque other than the force for load compensation.

2. A support, a first link member, one end of which is subjected to the weight of a load and the other end of which is input with a force for compensating for the load, with respect to a rotation center serving as a fulcrum in the support; a first cable member that is connected between the position of the fulcrum of the first link member and the position where the force for load compensation is input, extends vertically downward from the position of the fulcrum of the first link member and the position where the force for load compensation is input, and has one end fixed; a torque applying means for applying a rotational torque for winding up the other end of the first cable member; Equipped with The first link member is The weight of a load object acts on the one end side, and a first pulley is provided on the other end side, The support is a second pulley that rotatably supports the first link member between the one end side and the other end side on a first rotation shaft that serves as the rotation center, and is installed coaxially with the first rotation shaft; a first winding mechanism that is installed vertically below the second pulley and that winds up the first cable member with a set rotational torque, one end of the first cable member is installed vertically below the first pulley of the first link member, the first cable member is wound around the first pulley and the second pulley, and the other end side is wound around the first winding mechanism, A load compensation device, wherein the torque applying means applies a rotational torque to the first winding mechanism for winding up the first cable member.

3. The torque applying means is a constant torque source that outputs a constant rotational torque; a torque adjusting means for varying and outputting the rotational torque output by the constant torque source; 3. The load compensation device according to claim 2, further comprising:

4. a second link member having one end side to which the weight of a load object acts and the other end side of which is rotatably supported on a second rotation shaft at the one end side of the first link member, and including a third pulley installed coaxially with the second rotation shaft; a fourth pulley rotatably supported on the support body by the first rotary shaft; a third link member having one end connected to the fourth pulley and the other end connected to a fifth pulley; a second cable member that is wound around the third pulley and the fourth pulley, maintains the second link member and the third link member parallel to each other, and transmits the rotational torque of the second link member about the second rotation axis and the rotational torque of the third link member about the first rotation axis; a third cable member having one end installed vertically below the fifth pulley of the third link member and wound around the fourth pulley and the fifth pulley; a second winding mechanism that is installed vertically below the fourth pulley and that winds up the other end of the third cable member with a set rotational torque; Equipped with 4. The load compensation device according to claim 2, wherein the torque applying means applies a rotational torque to the second winding mechanism for winding up the third cable member.

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