Pulley device, hoisting device, and method for controlling hoisting device

Abstract

To provide a pulley device capable of detecting looseness more accurately even if the direction in which a rope is unwound changes.SOLUTION: A pulley device includes: a first axis supported by a frame; a disk provided with a guide provided on one end side thereof and locked so as to be slidable in a direction perpendicular to the first axis and an opening provided on the other end side; a pulley wheel that is arranged along an outer circumference of the disk, and has a groove in which a linear body is attached to the outer circumference of the pulley, and rotates along the outer circumference of the disk with a central axis of the disk as a rotation axis; an energizing means attached in the guide, and energizing the guide away from the first axis; a limit switch arranged in the opening so as to face the guide; and a limit switch pressing member fixed to the first axis and having a pressing surface for pressing the limit switch when the energizing means extends beyond a predetermined length, the outer circumference of the pressing surface is formed such that a distance from a center of the first axis gradually increases in one direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a pulley device and the like. [Background technology]

[0002] Hoisting devices using a winding machine that winds up a linear object such as a rope and a pulley that controls the orientation of the linear object are used in various fields. In a typical hoisting device, an object is attached to the tip of the linear object, the orientation of the linear object is controlled by a pulley, and the linear object is wound and unwound by a winding machine, thereby moving the object up and down. During unwinding, the winding machine typically runs idle and the object is lowered by gravity. During unwinding, the descent speed of the object may decrease, for example, if the object runs over an obstacle. In this case, the unwinding speed becomes faster than the descent speed, causing excessive unwinding of the linear object, resulting in problems such as the linear object becoming tangled in the mechanism of the hoisting device or with other linear objects.

[0003] To prevent the above-mentioned problems, methods for detecting slack in a linear object due to a decrease in the descent speed of an object have been studied. For example, Patent Document 1 discloses technology for a slack detection device that detects slack in a rope in a hoisting device. This slack detection device allows the sheave shaft to move by making the sheave bearing section of a bracket (frame) that supports the sheave (pulley) around which the rope is stretched long and thin. A spring is also provided in the bearing section, and the sheave shaft compresses the spring when tension is applied to the rope. A limit switch is also provided to detect the movement of the sheave shaft. With this configuration, when the tension in the rope decreases, the sheave shaft moves due to the repulsive force of the spring, and the limit switch detects when the sheave shaft has moved beyond a predetermined value. When the limit switch detects the movement of the sheave shaft, slack in the rope can be detected. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 60-145341 Summary of the Invention [Problem to be solved by the invention]

[0005] In a hoisting device, it is generally desirable that the direction in which the rope is unwound downward from the pulley is constant. However, the direction in which the rope is unwound may change due to the influence of wind, water currents, and the like. When the direction in which the rope is unwound changes in this way, the magnitude of the force that the pulley receives from the rope changes even if the tension in the rope remains the same. However, the technology in Patent Document 1 detects slack according to the force that the pulley receives from the rope, regardless of the direction in which the rope is unwound. This poses a problem in that slack cannot be accurately detected when the direction in which the rope is unwound changes.

[0006] The present invention has been made in consideration of the above problems, and aims to provide a pulley device or the like that can more accurately detect slack even when the direction in which the rope is unwound changes. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the pulley device of the present invention includes a disk having a first shaft supported by a frame, a guide provided at one end side of the disk so as to penetrate from front to back and engaged with the first shaft so as to be slidable in a direction perpendicular to the extending direction of the first shaft, and an opening provided at the other end side of the disk so as to penetrate from front to back, and a pulley that is formed in an annular shape and has a groove disposed along the outer periphery of the disk and has a groove on its outer periphery to which a linear body is attached, and that rotates around the central axis of the disk along the outer periphery of the disk as a rotation axis. The device comprises a ring, a biasing means disposed within the guide and biasing the guide in a direction away from the first axis in a direction perpendicular to the extension direction of the first axis, a limit switch disposed in the opening so as to face the guide, and a limit switch pressing member having a pressing surface that presses the limit switch and is fixed to the first axis, the pressing surface pressing the limit switch when the biasing means extends beyond a predetermined length, the pressing surface being formed so that the distance from the first axis gradually increases in one direction.

[0008] In addition, the winding device of the present invention has the above-mentioned pulley device, a winding machine that winds and unwinds the linear body, and a control means that controls the winding and unwinding operations of the winding machine, and the limit switch pressing member is arranged so that the distance of the pressing surface from the center of the first axis gradually increases toward the winding machine.

[0009] The control method for a hoisting device of the present invention is a control method for a hoisting device having a pulley device to which a linear body is attached, a winding machine that winds and unwinds the linear body, and control means for controlling the winding and unwinding operations of the winding machine, wherein the pulley device comprises a disk having a first shaft supported by a frame, a guide provided at one end side of the pulley device so as to penetrate from front to back and engaged with the first shaft so as to be slidable in a direction perpendicular to the extension direction of the first shaft, and an opening provided at the other end side of the pulley device so as to penetrate from front to back, a pulley wheel having a groove in which the linear body is attached, formed in an annular shape, arranged along the outer periphery of the disk, and rotating along the outer periphery of the disk with the central axis of the disk as the axis of rotation, and a pulley wheel provided within the guide that urges the guide in a direction perpendicular to the extension direction of the first shaft, away from the first shaft. a limit switch pressing member having a pressing surface that presses the limit switch and is fixed to the first shaft, the pressing surface pressing the limit switch when the biasing means extends beyond a predetermined length, the outer periphery of the pressing surface being formed so that the distance from the center of the first shaft gradually increases in one direction, and when the limit switch is not pressed, the winding machine is controlled to unwind at a predetermined unwinding speed, and when the limit switch is pressed, the winding machine is controlled to slow down the unwinding speed. [Effects of the Invention]

[0010] The effect of the present invention is to provide a pulley device that can more accurately detect slack even when the direction in which the rope is unwound changes. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a side view showing a pulley device according to a first embodiment of the present invention. [Figure 2] 1 is a cross-sectional view showing a pulley device according to a first embodiment of the present invention. [Figure 3]3 is a side view showing the shape of a limit switch pressing member used in the pulley device according to the first embodiment of the present invention. FIG. [Figure 4] FIG. 1 is a schematic diagram showing a first example of forces acting on a typical pulley. [Figure 5] FIG. 10 is a schematic diagram showing a second example of forces acting on a typical pulley. [Figure 6] FIG. 10 is a schematic diagram showing a third example of forces acting on a typical pulley. [Figure 7] 3A and 3B are schematic diagrams showing a first example of forces acting on the pulley device according to the first embodiment of the present invention. [Figure 8] 5A and 5B are schematic diagrams showing a second example of forces acting on the pulley device according to the first embodiment of the present invention. [Figure 9] 5A to 5C are schematic diagrams showing a third example of forces acting on the pulley device according to the first embodiment of the present invention. [Figure 10] 3 is a schematic diagram showing a first example of an operating state of a hoisting device using the pulley device of the first embodiment of the present invention. FIG. [Figure 11] 4A and 4B are schematic diagrams showing a second example of the operating state of a hoisting device using the pulley device of the first embodiment of the present invention. [Figure 12] 5A and 5B are schematic diagrams showing a third example of the operating state of a hoisting device using the pulley device according to the first embodiment of the present invention. [Figure 13] 5A and 5B are schematic diagrams showing a fourth example of the operating state of a hoisting device using the pulley device of the first embodiment of the present invention. [Figure 14] 5A and 5B are schematic diagrams showing a fifth example of the operating state of a hoisting device using the pulley device of the first embodiment of the present invention. [Figure 15] FIG. 10 is a schematic diagram showing a sixth example of the operating state of a hoisting device using the pulley device of the first embodiment of the present invention. [Figure 16] 4 is a flowchart showing the operation of the pulley device according to the first embodiment of the present invention. [Figure 17] 5 is a flowchart showing the operation of a hoisting device using the pulley device of the first embodiment of the present invention. [Figure 18]FIG. 4 is a side view showing a pulley device according to a second embodiment of the present invention. [Figure 19] FIG. 4 is a cross-sectional view showing a pulley device according to a second embodiment of the present invention. [Figure 20] FIG. 10 is a side view showing a first state of a slider according to a second embodiment of the present invention. [Figure 21] FIG. 10 is a side view showing a second state of the slider according to the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the embodiments described below are limited to technically preferable aspects for carrying out the present invention, but are not intended to limit the scope of the invention. Note that similar components in each drawing are given the same reference numerals, and their description may be omitted.

[0013] (First embodiment) Fig. 1 is a side view showing a pulley device 10 according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view showing the pulley device according to the first embodiment of the present invention. Fig. 3 is a side view showing the shape of a limit switch pressing member 7 used in the pulley device 10 according to the first embodiment of the present invention. The pulley device 10 has a first shaft 2 supported by a frame 1, a disk 3, a pulley wheel 4, a biasing means 5, a limit switch 6, and the limit switch pressing member 7.

[0014] The first shaft 2 is supported by a frame 1. The frame 1 is fixed to a mount 20, for example.

[0015] The disk 3 has a guide 3a and an opening 3b. The guide 3a is provided on one end side of the disk 3 so as to penetrate from the front to the back, and is engaged with the first shaft 2 so as to be slidable in a direction perpendicular to the extension direction of the first shaft 2. The opening 3b is provided on the other end side of the disk 3 so as to penetrate from the front to the back.

[0016] The pulley 4 has a groove 4a. A linear body is attached to the groove 4a. More specifically, the groove 4a is formed in a ring shape along the outer periphery of the pulley 4. The linear body is attached along the groove 4a. The pulley 4 is formed in a ring shape and arranged along the outer periphery of the disk 3. The pulley 4 rotates along the outer periphery of the disk 3 with the central axis of the disk 3 as its axis of rotation. The linear body is, for example, a rope, string, cable, wire, etc.

[0017] The biasing means 5 is disposed inside the guide 3a, and biases the guide 3a in a direction perpendicular to the extension direction of the first shaft 2 and away from the first shaft 2. Specifically, the biasing means 5 is, for example, a spring.

[0018] The limit switch 6 is disposed in the opening 3b so as to face the guide 3a. When the limit switch 6 is pressed, it outputs a signal indicating that it has been pressed.

[0019] The limit switch pressing member 7 has a pressing surface 7a that presses down the limit switch 6. The limit switch pressing member 7 is fixed to the first shaft 2. When the biasing means 5 is extended beyond a predetermined length, the pressing surface 7a presses down the limit switch 6. The pressing surface 7a is formed so that the distance from the center of the first shaft 2 gradually increases in one direction.

[0020] FIG. 3 is a side view showing the shape of the limit switch pressing member used in the pulley device of the first embodiment of the present invention. As shown in FIG. 3, the limit switch pressing member 7 is fixed to the first shaft 2 so as not to rotate. The limit switch pressing member 7 includes a pressing surface 7a whose distance from the center G of the first shaft 2 gradually increases in one direction. Then, when the biasing means 5 extends beyond a predetermined length, the outer periphery of the limit switch pressing member 7 presses the limit switch 6. The mounting angle of the limit switch pressing member 7 is set so that the pressing surface 7a presses the limit switch 6 when looseness occurs, according to the tension and the direction in which the linear body is unwound. This setting will be described later. In the example of FIG. 3, the distances from the center G of the first shaft 2 to the point 7a1 at one end, the point 7a2 at the center, and the point 7a3 at the other end of the pressing surface 7a are R1, R2, and R3, respectively. And it has a shape where R1 < R2 < R3.

[0021] The operation of the pulley device 10 will be described later. Before that, the direction in which the linear body is unwound and the force that a general pulley receives from the linear body will be explained. FIG. 4 is a schematic diagram showing a first example of the force acting on a general pulley 90. FIG. 5 is a schematic diagram showing a second example of the force acting on a general pulley. FIG. 6 is a schematic diagram showing a third example of the force acting on a general pulley. Here, let the rotation center of the general pulley 90 be O. In FIGS. 4, 5, and 6, one side (horizontal direction) of the linear body 30 is connected to a hoisting machine (not shown), and the other side (downward direction) is connected to a suspended object (not shown).

[0022] FIG. 4 shows a state where the linear body 30 on the suspended object side is inclined more toward the hoisting machine side than vertically. Let the angle formed by the linear bodies 30 on both sides of the general pulley 90 be α and the tension acting on the linear body 30 be F. Then, the force P1 acting on the general pulley 90 is expressed by the following equation. P1 = 2 × F × cos(α / 2) (Equation 1) 5 shows a state in which the linear body 30 on the suspended object side faces vertically downward. If the angle formed by the linear body 30 on both sides of a general pulley 90 is β and the tension acting on the linear body 30 is F, then the force P2 acting on the general pulley 90 is expressed by the following equation: P2=2×F×cos(β / 2) (Formula 2) 6 shows a state in which the linear body 30 on the suspended object side is tilted away from the winch rather than vertical. If the angle formed by the linear body 30 on both sides of a typical pulley 90 is γ and the tension acting on the linear body 30 is F, then the force P3 acting on the typical pulley 90 can be expressed by the following equation: P3=2×F×cos(γ / 2) (Equation 3) In the above formula 1-3, cos(α / 2)>cos(β / 2)>cos(γ / 2) (Equation 4) Therefore P1>P2>P3 (Formula 5) is.

[0023] As described above, when linear body 30 on the suspended object side is tilted, even if the tension applied to linear body 30 is the same, the magnitude of the force acting on a typical pulley 90 will differ.

[0024] Next, states of the pulley device 10 of this embodiment corresponding to FIGS. 4-6 will be described. FIG. 7 is a schematic diagram showing a first example of forces acting on the pulley device 10 of the first embodiment of the present invention. FIG. 8 is a schematic diagram showing a second example of forces acting on the pulley device 10 of the first embodiment of the present invention. FIG. 9 is a schematic diagram showing a third example of forces acting on the pulley device 10 of the first embodiment of the present invention. FIGS. 7, 8, and 9 correspond to FIGS. 4, 5, and 6, respectively. In the pulley device 10 of this embodiment, the center O of the disk 3, which is the axis of rotation of the pulley device 4, is offset from the center G of the first shaft supporting the disk 3. The greater the force applied to the pulley device 4 from the linear body 30, the more the biasing means 5 is compressed, and the closer the center O of the disk 3 is to the center G of the first shaft. The greater the inclination of the disk 3 from a state without tension F.

[0025] Figure 7 shows a state in which the linear body 30 on the suspended object side is tilted toward the hoist rather than vertically. If the angle formed by the linear body 30 on both sides of the pulley device 10 is α and the tension acting on the linear body 30 is F, the force acting on the pulley wheel 4 is P1 expressed by Equation 1, as in the case of Figure 4. If the spring constant of the biasing means 5 is k, the center O of the disk 3 approaches the center G of the first shaft by a length L1 expressed by the following equation: L1=k·P1 (Formula 4) By P1, Figure 8 shows a state in which linear body 30 on the suspended object side faces vertically downward. If the angle formed by linear body 30 on both sides of pulley apparatus 10 is β and the tension acting on linear body 30 is F, then the force acting on pulley 4 is P2, as expressed in Equation 2, just as in the case of Figure 5. Therefore, center O of disk 3 approaches center G of the first shaft by length L2, expressed in the following equation. L2=k·P2 (Equation 5) Figure 9 shows a state in which linear body 30 on the suspended object side is tilted away from the winch rather than perpendicular. If the angle formed by linear body 30 on both sides of pulley device 10 is γ and the tension acting on linear body 30 is F, the force acting on pulley 4 is P3 expressed by equation 3, as in the case of Figure 6. Therefore, center O of disk 3 moves closer to center G of the first shaft by length L3 expressed by the following equation. L3=k·P3 (Equation 6) Next, a specific example of the operation of a hoisting device using the pulley device 10 will be described. Fig. 10 is a schematic diagram showing a first example of the operating state of a hoisting device using the pulley device of the first embodiment of the present invention. The hoisting device 100 has the pulley device 10, a winding machine 40, and control means 41. The winding machine 40 winds and unwinds the linear body 30.

[0026] The control means 41 controls the winding and unwinding operations of the winder 40 .

[0027] In the pulley device 10, the limit switch pressing member 7 is arranged so that the distance from the pressing surface 7a of the limit switch pressing member 7 to the center G of the first shaft gradually increases toward the winding machine 40.

[0028] Figure 10, like the example in Figure 7, shows a case in which linear object 30 on the suspended object side is tilted by angle α toward winder 40. Here, assume that the tension during normal unwinding is F. When tension is F, a force P1 acts on pulley 4, as in the example in Figure 6. Disk 3 is tilted by α / 2 compared to when there is no tension. At this time, limit switch 6 is set to face point 7a1, the farthest from G on limit switch pressing member 7. P1 compresses biasing means 5, bringing center G of the first shaft and center O of disk 3 closer by L1 in Equation 4. At the same time, point 7a1 is maintained in a state in which it does not press limit switch 6. At this time, point 7a1 is maintained in a position in contact with or close to contact with limit switch 6. This positional relationship is achieved by a design based on P1, spring constant k, and distance R1 between G and 7a.

[0029] Fig. 11 is a schematic diagram showing a second example of the operating state of a hoisting device using the pulley device of the first embodiment of the present invention. Fig. 11 shows a state in which slack occurs in linear body 30 in the state of Fig. 10, and the tension decreases from F to F'. As the tension decreases from F to F', the force with which linear body 30 pushes pulley wheel 4 also decreases from P1 to P1'. This change causes biasing means 5 to elongate, and center O of disk 3 moves closer to center G of the first shaft. This movement causes point 7a1 on pressing surface 7a of limit switch pressing member 7 to press limit switch 6.

[0030] When limit switch 6 is pressed, limit switch 6 outputs a signal indicating that limit switch 6 has been pressed to control means 41. Upon receiving this signal, control means 41 detects slack in linear body 30. When control means 41 detects slack in linear body 30, it controls winding machine 40 to reduce the unwinding speed of linear body 30. The amount by which the unwinding speed is reduced can be set arbitrarily. Furthermore, control means 41 may, for example, set the unwinding speed to zero to stop unwinding. Furthermore, control means 41 may gradually reduce the unwinding speed rather than suddenly stop unwinding. Through the above-described operations, the pulley device of the first embodiment of the present invention can detect slack in linear body 30 and prevent problems such as excessive unwinding of linear body 30 from winding machine 40.

[0031] FIG. 12 is a schematic diagram showing a third example of the operating state of a hoisting device using the pulley assembly of the first embodiment of the present invention. Similar to the example of FIG. 8, FIG. 12 illustrates a case in which the linear body 30 on the suspended object side faces vertically downward, and the angle between the linear body 30 on the winding machine 40 side and the linear body 30 on the suspended object side is β. When the tension is at the normal value F, similar to the example of FIG. 7, a force P2 acts on the pulley 4. The disk 3 is tilted by β / 2 compared to when there is no tension. At this time, the limit switch 6 is set to face the center point 7a2 of the pressing surface 7a of the limit switch pressing member 7. The biasing means 5 is compressed by P2, and the center G of the first shaft and the center O of the disk 3 approach each other by the distance L2 in Equation 4. At the same time, point 7a2 is maintained in a state in which it does not press the limit switch 6. At this time, point 7a2 does not press the limit switch 6, but point 7a2 is brought into contact with the limit switch 6 or is held in a position close to contact. As explained above, L2 is smaller than L1, but the distance R2 between G and 7a2 is shortened accordingly. Therefore, as in Figure 9, point 7a2 can be brought into contact with the limit switch 6 or held in a position close to contact.

[0032] FIG. 13 is a schematic diagram showing a fourth example of the operating state of a hoisting device using the pulley device of the first embodiment of the present invention. FIG. 13 shows a state in which slack occurs in linear body 30 in the state shown in FIG. 12 , causing the tension to decrease from F to F′. As the tension decreases from F to F′, the force with which linear body 30 pushes pulley wheel 4 also decreases from P2 to P2′. This change causes biasing means 5 to elongate, and center O of disk 3 moves closer to center G of the first shaft. This movement causes point 7a2 on pressing surface 7a of limit switch pressing member 7 to press limit switch 6. Control means 41 then receives the output of limit switch 6, detects slack in linear body 30, and controls winding machine 40 to reduce its unwinding speed. This control prevents excessive unwinding of linear body 30 from winding machine 40.

[0033] FIG. 14 is a schematic diagram showing a fifth example of the operating state of a hoisting device using the pulley assembly according to the first embodiment of the present invention. Similar to the example shown in FIG. 9, FIG. 14 illustrates a case in which the linear body 30 on the suspended object side is tilted away from the hoist, forming an angle γ between the linear body 30 on both sides of the pulley assembly 10. When tension is at the normal value F, a force P3 acts on the pulley wheel 4, similar to the example shown in FIG. 9. The disk 3 is tilted by γ / 2 compared to when there is no tension. At this time, the limit switch 6 is set to face point 7a3 on the end of the pressing surface 7a of the limit switch pressing member 7 facing the winding machine 40. The biasing means 5 is compressed by P3, and the center G of the first shaft and the center O of the disk 3 approach each other by the distance L3 in Equation 4. At the same time, point 7a3 is maintained in a non-pressing state. At this time, point 7a3 does not press the limit switch 6, but point 7a3 is kept in contact with the limit switch 6 or in a position close to contact. As explained above, L3 is smaller than L2, but the distance R3 between G and 7a3 is shortened accordingly. Therefore, as in the examples of Figures 9 and 11, point 7a3 can be kept in contact with the limit switch 6 or in a position close to contact.

[0034] FIG. 15 is a schematic diagram showing a sixth example of the operating state of a hoisting device using the pulley device according to the first embodiment of the present invention. FIG. 15 shows a state in which slack occurs in linear body 30 in the state shown in FIG. 14 , causing the tension to decrease from F to F′. As the tension decreases from F to F′, the force with which linear body 30 pushes pulley wheel 4 also decreases from P3 to P3′. This change causes biasing means 5 to elongate, and center O of disk 3 moves closer to center G of the first shaft. This movement causes point 7a3 on pressing surface 7a of limit switch pressing member 7 to press limit switch 6. Control means 41 then receives the output of limit switch 6, detects slack in linear body 30, and controls winding machine 40 to reduce its unwinding speed. This control prevents excessive unwinding of linear body 30 from winding machine 40.

[0035] The pulley device 10 of this embodiment has been described above using specific examples. Here, the operation of the pulley device will be summarized. FIG. 16 is a flowchart showing the operation of the pulley device of the first embodiment of the present invention. First, the description begins with the case where the tension of the linear body 30 is at normal value F. Here, the pulley device 10 holds the disk at a position and angle where limit switch 6 is not pressed by the tension of the linear body 30 (S1). At this time, as described above, the limit switch pressing member 7 is held at a position where it does not press limit switch 6 but is close to contacting limit switch 6. Furthermore, this positional relationship is achieved regardless of the orientation of the linear body 30 on the suspended object side. Next, if limit switch 6 is pressed (S2_Yes), a signal indicating that the limit switch has been pressed is output (S3). This signal can be used to detect slack in the linear body 30. On the other hand, if the limit switch is not pressed (S2_No), the process returns to S1.

[0036] Next, the operation of the hoisting device 100 using the pulley device 10 will be described. FIG. 17 is a flowchart showing the operation of the hoisting device 100 using the pulley device 10 according to the first embodiment of the present invention. First, the explanation will start from the case where the tension of the linear body 30 is normal value F. At this time, the control means 41 controls the winding machine 40 to unwind the linear body 30 at a predetermined speed (S11). Next, it is determined whether a signal has been received from the limit switch 6 (S12). Here, if a signal has been received from the limit switch 6 (S12_Yes), the control means 41 detects slack in the linear body 30 upon receiving the signal (S13). Then, the control means 41 controls the winding machine 40 to reduce the unwinding speed (S13). This control can prevent the linear body 30 from being excessively unwound from the winding machine 40. By the above control, the hoisting device 100 can prevent the problem of excessive unwinding of the linear body 30 from the winding machine 40, regardless of the orientation of the linear body 30 on the suspended object side. On the other hand, if no signal is received from the limit switch 6 in S12 (S12_No), the process returns to S11.

[0037] The pulley device 10 and the like according to the first embodiment have been described above.

[0038] A pulley device 10 according to a first embodiment of the present invention includes a first shaft 2 supported by a frame 1, a disk 3, a pulley 4, a biasing means 5, a limit switch 6, and a limit switch pressing member 7. The first shaft 2 is supported by the frame 1. The disk 3 includes a guide 3a and an opening 3b. The guide 3a is provided on one end of the disk 3 so as to penetrate from front to back. The guide 3a is engaged with the first shaft 2 so as to be slidable in a direction perpendicular to the extension direction of the first shaft 2. The other end of the pulley 4 includes an opening 3b that penetrates from front to back. The pulley 4 has a groove 4a to which a linear body is attached. The pulley 4 is annular, is arranged along the outer periphery of the disk 3, and rotates around the central axis of the disk 3 as the axis of rotation. The biasing means 5 is disposed within the guide 3a and biases the guide 3a in a direction perpendicular to the extension direction of the first shaft 2 and away from the first shaft 2. The limit switch 6 is disposed in the opening 3b so as to face the guide 3a. The limit switch pressing member 7 has a pressing surface 7a that presses the limit switch 6 and is fixed to the first shaft 2. When the biasing means 5 is extended beyond a predetermined length, the pressing surface 7a presses the limit switch 6. The pressing surface 7a is formed so that the distance from the center G of the first shaft gradually increases in one direction.

[0039] When the unwinding direction of the linear body 30 attached to the pulley 4 changes, the direction and magnitude of the force that the pulley 4 receives from the linear body 30 change, even if the tension F remains the same. In this case, in the pulley device 10 of this embodiment, the disk 3 tilts depending on the direction of the force, and the biasing means 5 is compressed depending on the magnitude of the force. Here, the pressing surface 7a that presses the limit switch 6 is formed so that its distance from the center of the first shaft 2 gradually increases in one direction. Therefore, even if the unwinding direction of the linear body 30 changes, the distance between the pressing surface 7a and the limit switch 6 is maintained within a predetermined range that does not press the limit switch 6. In this state, if slack occurs in the linear body 30 and the tension F decreases, the pressing surface 7a presses the limit switch 6, and the slack is detected. In the above process, the limit switch 6 is pressed when the tension F decreases, regardless of the unwinding direction of the linear body 30. This makes it possible to provide a pulley device that can more accurately detect slack even when the direction in which the rope is unwound changes.

[0040] Moreover, the hoisting device 100 of this embodiment includes the above-described pulley device 10, a winding machine 40 that winds and unwinds the linear body 30, and control means 41 that controls the winding and unwinding operations of the winding machine 40. The limit switch pressing member 7 is arranged so that the distance from the center G of the first axis of the pressing surface 7a of the pulley device 10 gradually increases toward the winding machine 40. Furthermore, the control means 41 controls the winding machine 40 to unwind at a predetermined unwinding speed when the limit switch 6 is not pressed, and controls the winding machine 40 to slow down the unwinding speed when the limit switch 6 is pressed.

[0041] With this configuration, even if the unwinding direction of linear body 30 changes, due to the characteristics of pulley device 10, limit switch 6 is pressed when tension F decreases, regardless of the unwinding direction of linear body 30. Then, when limit switch 6 is pressed, control means 41 detects slack in linear body 30. Furthermore, when control means 41 detects slack, it controls winding machine 40 to slow down the unwinding speed. In this way, even if the unwinding direction of the rope changes, slack can be detected more accurately, and problems such as excessive unwinding of linear body 30 from winding machine 40 can be prevented.

[0042] The method for controlling a hoisting device of this embodiment controls a hoisting device 100 having a pulley device 10, a winding machine 40, and control means 41. A linear object 30 is attached to the pulley device 10. The pulley device 10 has a first shaft 2 supported by a frame 1, a disk 3, a pulley wheel 4, a biasing means 5, a limit switch 6, and a limit switch pressing member 7. The first shaft 2 is supported by the frame 1. The disk 3 has a guide 3a and an opening 3b. The guide 3a is provided at one end of the disk 3 so as to penetrate from front to back. The guide 3a is engaged with the first shaft 2 so as to be slidable in a direction perpendicular to the extension direction of the first shaft 2. The opening 3b is provided at the other end of the disk 3 so as to penetrate from front to back. The pulley wheel 4 has a groove 4a to which the linear object is attached. The pulley 4 is formed in an annular shape and is arranged along the outer periphery of the disk 3. The pulley 4 rotates around the central axis of the disk 3 along the outer periphery of the disk 3. The biasing means 5 is arranged within the guide 3a and biases the guide 3a in a direction perpendicular to the extension direction of the first shaft 2, away from the first shaft 2. The limit switch 6 is arranged in the opening 3b so as to face the guide 3a. The limit switch pressing member 7 has a pressing surface 7a that presses the limit switch 6 and is fixed to the first shaft 2. When the biasing means 5 extends beyond a predetermined length, the pressing surface 7a presses the limit switch 6. The pressing surface 7a is formed so that its distance from the center G of the first shaft gradually increases in one direction. The winder 40 winds and unwinds the linear body 30 via the pulley device 10. The control means 41 controls the winding and unwinding operations of the winder 40. When the limit switch 6 is not pressed, the control means 41 controls the winding machine 40 to unwind at a predetermined unwinding speed. When the limit switch 6 is pressed, the control means 41 controls the winding machine 40 to reduce the unwinding speed.

[0043] In the above-described control method for the hoisting device 100, even if the unwinding direction of the linear body 30 changes and the direction and magnitude of the force applied to the pulley device 10 change, the limit switch 6 is pressed at the timing when slack occurs due to the characteristics of the pulley device 10. This allows the control means 41 to more accurately detect slack in the linear body 30. When slack is detected, the control means 41 performs control to reduce the unwinding speed of the winding machine 40. As a result, the control method for the hoisting device 100 of this embodiment can prevent the linear body 30 from being excessively unwound from the winding machine 40, regardless of the unwinding direction of the linear body 30.

[0044] (Second embodiment) FIG. 18 is a side view showing a pulley device 11 according to a second embodiment of the present invention. FIG. 19 is a cross-sectional view showing the pulley device 11 according to the second embodiment of the present invention. Like the pulley device 10 according to the first embodiment, the pulley device 11 includes a first shaft 2 supported by a frame 1, a disk 3, a pulley wheel 4, a biasing means 5, a limit switch 6, and a limit switch pressing member 7. In addition to these components, the pulley device 11 further includes a slider 8. The slider 8 is supported by the first shaft 2 so as to be rotatable about the center of the first shaft 2 as the axis of rotation, and supports the disk 3 so as to be slidable in the extension direction of the guide 3a. Descriptions of components similar to those of the first embodiment will be omitted.

[0045] 18 and 19, the slider 8 is attached to the first shaft 2 via a bearing 8a. This allows the slider 8 to rotate around the first shaft 2. The slider 8 and the disk 3 are connected by a slide mechanism, allowing the disk 3 to slide relative to the slider 8 in the extension direction of the guide 3a. The slide mechanism can be realized, for example, by a linear rail and a groove that fits into the rail.

[0046] 20 is a side view showing a first state of the slider of the second embodiment of the present invention, and FIG. 21 is a side view showing a second state of the slider of the second embodiment of the present invention.

[0047] In the example of FIG. 19, a pair of linear rails 3e are provided on the disk. The pair of linear rails 3e are arranged to sandwich the first shaft 2. The slider 8 is provided with a groove (not shown) that fits onto the rails 3e. The rails 3e slide along the groove, allowing the disk 3 to slide relative to the slider 8. By supporting the disk 3 with the slider 8, the disk 3 can rotate around the first shaft 2 and also slide. Note that this rotation means that the inclination of the disk 3 can be changed, and is different from the rotation of the pulley 4 that reels out the linear body 30.

[0048] Figure 20 shows a state in which no tension is applied to pulley 4 from linear body 30. Figure 21 shows a state in which force P4 caused by the tension of linear body 30 (not shown) is applied to pulley 4. When force P4 is applied, disk 3 tilts in the direction of force P4, and disk 3 slides in the direction of force P4.

[0049] By using the slider 8 to attach the disk 3 to the first shaft 2, the disk 3 can be supported more firmly on the first shaft 2 and can slide more smoothly than in a configuration in which the guide 3a is engaged with the first shaft 2.

[0050] The pulley device 11 and the like according to the second embodiment have been described above.

[0051] Similar to the pulley device 10 of the first embodiment, the pulley device 11 includes a first shaft 2 supported by a frame 1, a disk 3, a pulley wheel 4, a biasing means 5, a limit switch 6, and a limit switch pressing member 7. In addition to these, the pulley device 11 further includes a slider 8. The slider 8 is supported by the first shaft 2 so as to be rotatable about the center of the first shaft 2 as the axis of rotation, and supports the disk 3 so as to be slidable in the extension direction of the guide 3a. By attaching the disk 3 to the first shaft 2 using the slider 8, the disk 3 can be supported more firmly with respect to the first shaft 2 and can slide more smoothly than in a configuration in which the guide 3a is engaged with the first shaft 2.

[0052] The present invention has been described above using the above-described embodiment as an exemplary example. However, the present invention is not limited to the above-described embodiment. In other words, the present invention can be applied in various aspects that are understandable to those skilled in the art within the scope of the present invention. [Explanation of symbols]

[0053] 1 frame 2. First axis 3 Discs 4 Pulleys 5. Actuation means 6 limit switches 7 Limit switch pressing member 8 Slider 10, 11 Pulley device 20 Mounting stand 30 linear body 40 Winding machine 41 Control Means 90 General Pulley 100 Winding device

Claims

1. a first shaft supported by the frame; a disk having a guide provided at one end side thereof so as to penetrate from front to back and engaged with the first shaft so as to be slidable in a direction perpendicular to the extending direction of the first shaft, and an opening provided at the other end side thereof so as to penetrate from front to back; a pulley wheel having a groove in which a linear body is attached, formed in an annular shape, arranged along the outer periphery of the disk, and rotating along the outer periphery of the disk with the central axis of the disk as its rotation axis; a biasing means disposed within the guide and configured to bias the guide in a direction perpendicular to the extension direction of the first axis and away from the first axis; a limit switch disposed in the opening so as to face the guide; a limit switch pressing member having a pressing surface that presses the limit switch, the limit switch pressing member being fixed to the first shaft, the pressing surface pressing the limit switch when the biasing means is extended beyond a predetermined length; The outer periphery of the pressing surface is formed so that the distance from the center of the first axis gradually increases in one direction. A pulley device characterized by:

2. a slider that is supported by the first shaft so as to be rotatable about a rotation axis at the center of the first shaft and that supports the disk so as to be slidable in the extension direction of the guide; 2. The pulley assembly according to claim 1.

3. A pulley device according to claim 1 or 2; a winding machine that winds and unwinds the linear body; a control means for controlling the winding operation and the unwinding operation of the winding machine; and The limit switch depression member is arranged so that the distance of the depression surface from the center of the first axis gradually increases toward the winding machine. A hoisting device characterized by:

4. The control means When the limit switch is not pressed, the winding machine is controlled to unwind at a predetermined unwinding speed. When the limit switch is pressed, the winding machine is controlled to slow down the unwinding speed.

4. The hoisting device according to claim 3.

5. A control method for a hoisting device having a pulley device to which a linear body is attached, a winding machine that winds and unwinds the linear body, and control means that controls the winding operation and unwinding operation of the winding machine, comprising: The pulley device is a first shaft supported by the frame; a disk having a guide provided at one end side thereof so as to penetrate from front to back and engaged with the first shaft so as to be slidable in a direction perpendicular to the extending direction of the first shaft, and an opening provided at the other end side thereof so as to penetrate from front to back; a pulley wheel having a groove in which the linear body is attached, formed in an annular shape, arranged along the outer periphery of the disk, and rotating along the outer periphery of the disk with the central axis of the disk as its rotation axis; a biasing means disposed within the guide and configured to bias the guide in a direction perpendicular to the extension direction of the first axis and away from the first axis; a limit switch disposed in the opening so as to face the guide; and a limit switch pressing member having a pressing surface that presses the limit switch, the limit switch pressing member being fixed to the first shaft, the pressing surface pressing the limit switch when the biasing means is extended beyond a predetermined length, the outer periphery of the pressing surface is formed so that the distance from the center of the first shaft gradually increases in one direction; When the limit switch is not pressed, the winding machine is controlled to unwind at a predetermined unwinding speed. When the limit switch is pressed, the winding machine is controlled to slow down the unwinding speed. A method for controlling a hoisting device.

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