JP7545189B2 - Rotation lock device and hoist - Google Patents

Description

The present invention relates to a rotation lock device and a hoist.

Lever hoists are widely used for lifting and pulling loads, and securing loads with slings or the like (tightening loads). With this lever hoist, the chain can be wound up and unwound by manually operating the operating lever. An example of such a lever hoist is shown in Patent Document 1. In the lever hoist shown in Patent Document 1, in addition to a conventional brake mechanism (mechanical brake), two centrifugal members (31) and a housing ring (35) that houses the centrifugal members (31) are provided on the operating handle (12) side of the pinion frame (2B). The centrifugal members (31) are pressed against the inner peripheral surface of the housing ring (35) by the action of centrifugal force. This reduces the speed at which the load falls.

The above brake mechanism (mechanical brake) is configured as shown in, for example, Patent Document 2. This brake mechanism includes a pressure-receiving member (7) attached to the drive shaft (4) so as not to rotate, a drive member (8) screwed onto the drive shaft (4), a pair of brake plates (10a, 10b), a ratchet pawl (11) for preventing reverse rotation, and a ratchet pawl (12) attached to the ratchet shaft (15). The ratchet pawl (12) is biased by a spring (13) so that the ratchet pawl (12) engages with the locking teeth (11a) of the ratchet wheel (11). This engagement prevents the ratchet wheel (11) from rotating in the reverse direction, and a braking force acts on the rotation of the drive shaft (4) in the lowering direction.

DE102015121581A1 publication JP 2008-230726 A

Incidentally, when hoisting a hoist (lever hoist or chain block), a brake mechanism (mechanical brake) having a ratchet mechanism with a ratchet wheel having many ratchet teeth formed on its outer periphery and a pawl member that engages with the ratchet teeth may fail to function if there is a malfunction or damage to the engagement between the locking teeth (11a) of the ratchet wheel (11) and the ratchet pawl (12) as shown in Patent Document 2, for example. If the brake fails to function, the load sheave that winds up the chain may begin to rotate forcefully in the lowering direction due to the weight of the suspended load, causing the load to fall.

In the configuration disclosed in Patent Document 1, if the brake mechanism fails, the centrifugal member (31) is pressed against the inner peripheral surface of the housing ring (35) by the action of centrifugal force, which slows down the falling speed of the load (i.e., the rotation speed of the pinion). However, it cannot stop the load from falling.

In addition, in the configuration shown in Patent Document 2, the claw shaft (15) is attached to the frame (1b) by press-fitting or the like. However, because the thickness of the frame (1b) is relatively thin, as the length of the claw shaft (15) increases, the moment acting on the claw shaft (15) also increases. This means that it is necessary to increase the strength of the claw shaft (15) and its attachment portion accordingly. However, when the claw shaft (15) is attached by press-fitting into a hole in the frame (1b), there is a limit to how much the attachment strength can be improved.

Therefore, progress is being made in the development of a rotation lock device that can reliably stop the load from falling (rotating in the lowering direction) even in the event of a brake device failure.

In the rotation lock device under development, when the load chain is slackened when the load chain is hoisted with the lower hook attached to the lower end of the load chain and a hoisting operation is to be started, it takes time to remove the slack by operating the lever. For this reason, a method of removing the slack in the load chain in one go is sometimes used at work sites by performing a hoisting operation such as pulling the unloaded side of the load chain forcefully. However, in the above rotation lock device, when the slack in the load chain is removed, the rotation of the shaft-shaped member suddenly stops or suddenly decelerates. In that case, even if the load has not actually fallen (the operation is in the hoisting direction), there is a risk that the rotation lock device will be activated unintentionally, which creates the problem of the trouble of having to reset the rotation lock device.

The present invention has been made in consideration of the above circumstances, and aims to provide a rotation lock device and a hoist that can reliably stop the rotation of a shaft-shaped member in the lowering direction in the event of a brake device failure, etc., and can prevent the shaft-shaped member from becoming unable to rotate due to unintentional activation when the shaft-shaped member is rotated in the winding direction.

In order to solve the above problem, according to a first aspect of the present invention, there is provided a stopper support member that is attached to an axial member and rotates integrally with the axial member, a stopper member that is supported by the stopper support member in a state in which it can slide from the axial center side of the axial member toward the outside, a holding plate that is disk-shaped and rotatable relative to the stopper support member and holds the stopper member at a predetermined position on the stopper support member, a biasing means that biases the holding plate toward the stopper support member in a first rotation direction that is one rotation direction, and a stopper locking means that engages with the stopper member to stop the rotation of the axial member, wherein the stopper member has a stopper protrusion that protrudes toward the holding plate, and the holding plate has a guide groove that engages with the stopper protrusion and holds the stopper member at a predetermined position in the radial direction of the stopper support member, and the guide groove is a first restricting wall that engages with the stopper member at a predetermined position in the radial direction and is formed as an arc concentric with the axial member. and a second restricting wall which engages with the stopper member at a position where it protrudes outward from a predetermined position in the radial direction, the second restricting wall being provided on one side in the circumferential direction of the guide groove, so that when the axial member accelerates its rotation in the first rotation direction, the stopper support member and the retaining plate rotate relatively against the biasing force of the biasing means and the stopper projection disengages from the first restricting wall, the stopper member protrudes from the predetermined position to a position where it engages with the stopper locking means, stopping the rotation of the axial member, and a third restricting wall is provided on the other circumferential side of the guide groove, which engages with the stopper member at a position where it protrudes outward from the predetermined position in the radial direction, thereby preventing the retaining plate from rotating relatively to the stopper support member in a second rotation direction opposite to the first rotation direction, and when the stopper projection engages with the third restricting wall, the stopper member and the stopper locking means are located at a position where they are not locked.

In addition, in the above-mentioned invention, it is preferable that a return guide wall is provided on the other circumferential side of the third restricting wall for returning the stopper member to a predetermined position on the axial center side, and that the return guide wall is inclined toward the inner diameter side as it moves from one circumferential side to the other side.

In addition, in the above-mentioned invention, it is preferable that the third restricting wall and the return guide wall are provided on the inner wall of the movement restricting groove portion.

In addition, in the above-mentioned invention, it is preferable that the stopper support member is made of a soft magnetic material, and that a magnet that exerts a magnetic force in a direction that attracts them to each other is attached to at least one of the opposing portions of the radial inner diameter side of the stopper member and the stopper support member.

In addition, in the above-mentioned invention, it is preferable that magnets that exert magnetic forces in directions that attract each other are attached to both the radially inner diameter side of the stopper member and the opposing portion of the stopper support member.

In addition, in the above-mentioned invention, it is preferable that the retaining plate is provided with a protruding means protruding from the front or back surface of the retaining plate, and that the protruding means is positioned at a position where it abuts against the side surface of the stopper support member before or at the same time that the stopper protrusion abuts against the end of the guide groove opposite the first rotation direction when the retaining plate is urged in the first rotation direction by the urging means.

In addition, in the above-mentioned invention, the retaining plate is provided with a spring receiving protrusion that is formed by bending a part of the retaining plate and is positioned on the outer diameter side of the retaining plate relative to the biasing means, and it is preferable that the spring receiving protrusion catches the biasing means from falling off to the outer diameter side due to centrifugal force when the retaining plate rotates.

In addition, in order to solve the above-mentioned problems, according to a second aspect of the present invention, there is provided a hoist comprising a load sheave supported by a pair of frames and around which a chain for hoisting a load is wound, a drive shaft connected to the load sheave via a reduction gear, a brake device attached to the drive shaft, and an operating lever for rotating and driving the load sheave in the hoisting and lowering directions, wherein a rotation lock device according to each of the above-mentioned inventions is arranged on the outer periphery of the drive shaft, the shaft-shaped member is the drive shaft, and the stopper engagement means is attached to the frame.

The present invention provides a rotation lock device and a hoist that can reliably stop the rotation of the shaft-shaped member in the winding-down direction in the event of a brake device failure, etc., and can prevent the shaft-shaped member from becoming unable to rotate due to unintentional activation when the shaft-shaped member is rotated in the winding direction.

FIG. 1 is a front view showing an example of the configuration of a lever hoist to which a rotation lock (load drop prevention) device according to a first embodiment of the present invention is attached. FIG. 2 is a cross-sectional view showing the configuration of the lever hoist shown in FIG. FIG. 2 is a cross-sectional view showing a configuration in the vicinity of a rotation lock (load drop prevention) device of the lever hoist shown in FIG. 1. FIG. 4 is an exploded perspective view showing the configuration of the rotation lock (load drop prevention) device shown in FIG. 3 . 2 is a plan view showing a stopper member of the lever hoist shown in FIG. 1 and also showing a guide groove in a see-through manner. FIG. FIG. 2 is a front view showing a holding plate located on the X1 side of the lever hoist shown in FIG. 1 . FIG. 2 is a front view showing a holding plate located on the X2 side of the lever hoist shown in FIG. 1 . FIG. 2 is a diagram showing the configuration of the lever hoist shown in FIG. 1 in the vicinity of a rotation lock (load drop prevention) device, and also shows in a transparent manner the positional relationship of each part before the rotation lock (load drop prevention) device is activated. 9 is a transparent view showing the positional relationship of each part when the stopper support member and the holding plate rotate relatively from the state shown in FIG. 8 and the stopper projection reaches the allowable groove portion; FIG. 10 is a transparent view showing the positional relationship of each part when the stopper member protrudes radially outward from the state shown in FIG. 9 and the stopper protrusion is positioned in the return restriction groove portion; FIG. 9 is a transparent view showing the positional relationship of each part when the stopper support member and the holding plate rotate relatively from the state shown in FIG. 8 and the stopper protrusion enters the movement restricting groove portion; FIG. 12 is an enlarged view showing the positional relationship in the vicinity of the movement restricting groove portion in the state shown in FIG. 11 . FIG. 13 is an enlarged view showing a state in which the stopper projection has slid along the return guide wall due to the action of the tensile force of the biasing spring from the state shown in FIG. 12 . FIG. FIG. 13 is a diagram showing a modified example of the present invention in which a magnet is disposed in a recess on the bottom surface side of the stopper member 130 and also in a recess on the bottom surface side of the stopper support member. 15A is a diagram showing a state in which two magnets are spaced a distance Y apart in the configuration shown in FIG. 14 , and FIG. 15B is a diagram showing a state in which the magnets and the bottom surface of the stopper member are spaced a distance Y/2 apart in the configuration shown in FIG. 5 .

[First embodiment]
Hereinafter, the lever hoist 10 according to the first embodiment of the present invention will be described with reference to the drawings. In the following description, the X direction is the axial direction of the drive shaft 25, the X1 side is the side where the idling grip 60 is attached, and the X2 side is the opposite side, that is, the gear box 34 side. The Z direction is the vertical direction (suspension direction; hoisting/lowering direction) in the suspended state of the lever hoist 10, the Z1 side is the upper side in the suspended state, and the Z2 side is the lower side in the suspended state. The direction perpendicular to the X direction and the Z direction is the Y direction, the Y1 side is the right side in FIG. 1, and the Y2 side is the left side in FIG. 1. In the following description, the rotation direction of the load sheave 20 is the hoisting direction as one rotation direction and the hoisting direction as the other rotation direction. The rotation direction around the shaft connected to the load sheave 20 is based on the direction in which the load sheave 20 is rotated.

<Overall configuration of the lever hoist>
Fig. 1 is a front view showing an example of the configuration of a lever hoist 10 according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view showing the configuration of the lever hoist 10 shown in Fig. 1.

As shown in Figure 2, a load sheave 20 around which a chain C1 is looped is supported in a freely rotatable state between a pair of frames 11, 12 of the lever hoist 10. A load gear 21 that meshes with a small diameter gear portion 32 of a reduction gear 30 (described later) is non-rotatably provided on the load sheave 20. The configuration of the load sheave 20 will be described in detail later.

The load sheave 20 has an insertion hole 20a that penetrates in the axial direction (X direction), and a drive shaft 25 is inserted into the hollow hole of the load sheave 20. The drive shaft 25 corresponds to a shaft-shaped member. A male thread portion 26 that meshes with a female thread member 35 that constitutes a brake device 70 (described later) is provided on the outer periphery of the drive shaft 25 midway, and a pinion gear 27 that meshes with a large diameter gear portion 31 of the reduction gear 30 is provided on the other end side (X2 side) of the drive shaft 25. The reduction gear 30 also has a small diameter gear portion 32 that meshes with the load gear 21 described above.

A casing 13 is attached to the frame 11 to protect the driving parts such as the reduction gear 30 and the load gear 21. The male screw portion 26 is engaged with the female screw portion 36 of the female screw member 35. In addition to the female screw portion 36, the female screw member 35 is also provided with a switching gear 37 that can engage with a switching pawl 40 arranged on the operating lever 50. The switching pawl 40 is, for example, a ratchet pawl provided on one side and the other side, and the operating lever 50 is swung with the switching pawl 40 engaged with the switching gear 37 to transmit the driving force to the female screw member 35.

In addition, a switch knob 45 is fixed coaxially to the switch pawl 40, and by operating the switch knob 45, the transmission of driving force to the female screw member 35 can be switched between the winding direction, the lowering direction, or the neutral position. For example, in FIG. 1, when the lower side (Z2 side) of the switch knob 45 is tilted to the left, the winding switch pawl 40 meshes with the switch gear 37. As a result, when the operation of swinging the operating lever 50 is repeated, the switch gear 37 rotates in the winding direction but not in the lowering direction. At this time, it corresponds to the winding state of the chain C1.

On the other hand, for example, when the lower side (Z2 side) of the switching knob 45 is tilted to the right in FIG. 1, the switching claw 40 for lowering meshes with the switching gear 37. As a result, when the operation lever 50 is repeatedly swung, the switching gear 37 rotates in the lowering direction but not in the winding direction. Also, when switched to the neutral position, it is possible to transition to an idle state (at which time the load sheave 20 and drive shaft 25 also rotate) in which the chain C1 can be pulled out by hand. Furthermore, by operating the idle grip 60 described later, the chain C1 can be quickly wound up or lowered without operating the operation lever 50.

The cam member 55 is attached to the drive shaft 25 in a non-rotatable state, for example, by a spline connection or a key connection. Furthermore, a member called a free-wheel grip 60 is attached to the cam member 55 so that it can slide a predetermined amount in the axial direction relative to the cam member 55. In the position shown in FIG. 2, the free-wheel grip 60 is non-rotatably engaged with the cam member 55, but when the free-wheel grip 60 is slid in the X1 direction, the free-wheel grip 60 becomes rotatable within a certain range relative to the cam member 55. The free-wheel grip 60 is a roughly cylindrical knob-like part that can rotate together with the drive shaft 25 via the cam member 55, and can be gripped by the operator's hand.

This free-wheel grip 60 is connected to the female thread member 35 by a first torsion spring (not shown), and is further connected to one end of the drive shaft 25 by a second torsion spring (not shown). When the switch knob 45 is in the neutral position and the free-wheel grip 60 is slid in the X1 direction in FIG. 2, the free-wheel grip 60 rotates a predetermined amount in the winding down direction by the biasing force of the second torsion spring (free-wheel spring). The first torsion spring attached to the free-wheel grip 60 that has rotated a predetermined amount also rotates in the winding down direction, and the biasing force that had been rotating the female thread member 35 in the winding up direction until then is released, and the mode switches to free-wheel mode. Here, regardless of whether the mode is free-wheel mode or not, if the operator grips the free-wheel grip 60 by hand and rotates it in the winding up direction, the rotational force can be transmitted to the drive shaft 25. Therefore, by rotating the free-wheel grip 60, the length of the chain C1 can be quickly adjusted, and by sliding it, it is possible to switch to free-wheel mode. Also, even in the free-running mode, when tension greater than a specified level acts on the chain C1 in the winding down direction, the threaded member 35 rotates relative to the drive shaft 25 in the winding up direction, which is the tightening direction, and the brake of the brake device 70, which will be described later, is activated.

<Regarding the Brake Device 70>
2, a brake device 70 is disposed on the drive shaft 25 connected to the load sheave 20 via a gear. The brake device 70 mainly includes a brake receiver 71, brake plates 72a, 72b, a ratchet wheel 80, a ratchet member 90, a ratchet shaft 115, a bushing 92, and a female thread member 35. The ratchet wheel 80, the ratchet member 90, and the ratchet shaft 115 correspond to the main components of the ratchet mechanism.

The brake receiver 71 has a flange portion 71a and a hollow boss portion 71b. The flange portion 71a is a portion that is provided with a larger diameter than the hollow boss portion 71b, and is capable of receiving the brake plate 72a.

The hollow boss portion 71b is located closer to the female thread member 35 (X1 side) than the flange portion 71a, and supports the ratchet wheel 80 via a bushing 92. The inner periphery of the hollow boss portion 71b meshes with the drive shaft 25 by a spline connection or the like, so that the drive shaft 25 and the brake receiver 71 rotate together.

Brake plates 72a and 72b are supported by the hollow boss 71b between the flange 71a and the ratchet wheel 80, and between the female thread member 35 and the ratchet wheel 80. The brake plates 72a and 72b are, for example, friction materials formed into plates from a specific friction material, or are arranged on both sides of the ratchet wheel 80 by sintering or the like.

When the female screw member 35 is rotated in the winding direction, the female screw member 35 presses the ratchet wheel 80 together with the brake plates 72a and 72b toward the brake receiver 71 due to the action of the male screw portion 26 of the drive shaft 25, and transmits the driving force to the drive shaft 25. On the other hand, even if the drive shaft 25 is rotated in the winding down direction in this state, the female screw member 35 presses the ratchet wheel 80 together with the brake plates 72a and 72b toward the brake receiver 71. At this time, the ratchet wheel 80 is prevented from rotating in the winding down direction by the claw member 90, so a braking force due to frictional force acts on the brake device 70. This makes it possible to stop the rotation of the drive shaft 25 in the winding down direction. On the other hand, when the female screw member 35 is rotated in the winding down direction, the pressing force by the female screw member 35 is loosened accordingly, the braking force of the brake device 70 is reduced, and it becomes possible to rotate in the winding down direction.

A claw shaft 115 is integrally provided on the stopper support member 120, which will be described later, and the claw member 90 is rotatably supported on the claw shaft 115. A coil portion 93a of a torsion spring 93 is attached to the claw shaft 115, and the torsion spring 93 applies a biasing force in a direction in which the claw member 90 is pressed against the ratchet teeth 83 of the ratchet wheel 80. In this way, the ratchet wheel 80 is rotatable in the winding direction, and its rotation in the unwinding direction is restricted for each pitch angle divided by the number of teeth of the ratchet wheel 80. A pair of claw members 90 are provided, and are arranged 180 degrees apart in the circumferential direction of the ratchet wheel 80.

As shown in FIG. 2, the brake device 70 is covered with a brake cover 14 to prevent dust, rainwater, etc. from entering the brake device 70 inside the brake cover 14.

<Load sheave 20 and rotation lock (load drop prevention) device 100>
Next, the load sheave 20 and the rotation lock (load fall prevention) device 100 will be described. Fig. 3 is a cross-sectional view showing the configuration near the rotation lock (load fall prevention) device 100. Fig. 4 is an exploded perspective view showing the configuration of the rotation lock (load fall prevention) device 100 shown in Fig. 3. As shown in Figs. 3 and 4, the rotation lock (load fall prevention) device 100 mainly includes a stopper engaging member 110, a stopper support member 120, a stopper member 130, a holding plate 140, and a biasing unit 150. The stopper engaging member 110 corresponds to the stopper engaging means, and the biasing unit 150 corresponds to the biasing means.

2 to 4, in this embodiment, a pair of stopper locking members 110 are attached to the ratchet wheel 80 side of the frame 12. In this embodiment, the stopper locking members 110 are long pieces that are long in the Y direction, and a space SP1 is formed between the two stopper locking members 110. This makes it possible to reduce the weight of the stopper locking members 110 compared to when the stopper locking members are provided around the entire outer periphery of the stopper support member 120 and the retaining plate 140.

Each stopper locking member 110 is attached to the frame 12 via two stay bolts B1, and to enable such attachment, two mounting holes 111 are provided in the stopper locking member 110, and the stay bolts B1 are inserted into the mounting holes 111. Note that, although a pair (two) of mounting holes 111 are provided in this embodiment, it is also possible to provide three or more mounting holes.

The stopper locking member 110 is provided with an inner protrusion 112. The inner protrusion 112 is a portion of the stopper locking member 110 that protrudes toward the center of the shaft hole 12b of the frame 12. The shaft hole 12b is a hole through which the drive shaft 25 and the load sheave 20 described above are inserted.

The inner protrusion 112 faces the outer peripheral surfaces of the stopper support member 120 and the holding plate 140 described later with a slight gap therebetween. This allows the stopper support member 120 and the holding plate 140, which support the stopper member 130 in the holding position, to rotate without any hindrance. In this embodiment, one inner protrusion 112 is provided on each stopper locking member 110. Therefore, two inner protrusions 112 are arranged at 180 degree intervals in the circumferential direction.

The inner protrusion 112 is provided with a locking wall 114. The locking wall 114 is a wall surface on the other side in the rotation direction of the inner protrusion 112 (the clockwise side of the inner protrusion 112 in Figs. 3 and 4), and the stopper member 130, which rotates in one rotation direction (lowering direction), collides with the locking wall 114 when it protrudes radially outward from the stopper support member 120, thereby making it possible to stop the rotation of the load sheave 20. For this reason, the locking wall 114 is set at an inclination angle with respect to the radial direction of the shaft hole 12b so as not to push back the stopper member 130, which will be described later, in the direction of the rotation axis. In addition, the side surface of the stopper member 130 also has a side surface with an inclination angle that is not pushed back in the direction of the rotation axis by colliding with the locking wall 114. As shown in Fig. 4, a concave portion 113 is provided that is continuous with the locking wall 114 and is recessed in a direction away from the direction of the rotation axis (outer diameter side). One hook portion (not shown) of the torsion spring 93 is engaged with this recess 113, making it possible to prevent contact between the stopper member 130 and the hook portion of the torsion spring 93.

4, the stopper locking member 110 is provided with a claw shaft 115. In this embodiment, the claw shaft 115 is integrated with other parts of the stopper locking member 110. For such integration, the stopper locking member 110 is preferably formed by casting (e.g., the lost wax method). However, it is also possible to form only the claw shaft 115 separately and attach the claw shaft 115 by pressing it into an attachment hole or the like present in the stopper locking member 110.

3, multiple ribs 116 are arranged inside the stopper locking member 110. In other words, the stopper locking member 110 is not a solid member, but a member with a hollow portion formed by the multiple ribs 116, making it possible to reduce the weight of the stopper locking member 110. In addition, two ribs 116 are arranged at the base side of the claw shaft 115 so as to form an X, making it possible to receive a load in the axial direction (thrust direction) of the claw shaft 115.

In this embodiment, as shown in Fig. 3, the side wall of the inner protrusion 112 opposite the locking wall 114 may also function as the locking wall 114. In addition, among the side walls facing the recessed portion 113, the side wall on the clockwise side in Figs. 3 and 4 may be configured to be inclined at a predetermined angle or more with respect to the radial direction, so that the stopper member 130 protruding from the stopper storage portion 123 is stored in the stopper storage portion 123 described later.

Next, the stopper support member 120 will be described. The stopper support member 120 has a central hole 121 and is attached to the drive shaft 25 at the central hole 121, so that the stopper support member 120 and the drive shaft 25 rotate together. The stopper support member 120 can be attached to the drive shaft 25 by any means capable of transmitting the required torque, such as a set screw, key connection, or spline connection.

4, the stopper support member 120 is provided with a bearing boss portion 122. The bearing boss portion 122 is a hollow shaft-shaped portion that protrudes in the axial direction (X direction) and is rotatably fitted into a central hole 142 provided in the holding plate 140.

In addition, the stopper support member 120 is provided with a stopper storage section 123 that extends from the center hole 121 side toward the outer periphery. The stopper storage section 123 is a section that stores the stopper member 130 described below, and its outer periphery side is open. Therefore, the stopper member 130 stored in the stopper storage section 123 is capable of protruding toward the outer periphery side, and is supported slidably by the side wall 123a of the stopper storage section 123.

The stopper storage section 123 is formed by being sandwiched between the narrow piece portion 120a and the wide piece portion 120b. When the stopper member 130 described later hits the locking wall 114, the narrow piece portion 120a is located at a position facing the inner protrusion portion 112, while the wide piece portion 120b is located at a position away from the inner protrusion portion 112 (locking wall 114) across the stopper storage section 123. In the configuration shown in FIG. 3, the narrow piece portion 120a is located on the left side of the stopper storage section 123, and the wide piece portion 120b is located on the right side of the stopper storage section 123. Here, the wide piece portion 120b is provided with a wider circumferential width than the narrow piece portion 120a. Therefore, even if the stopper member 130 hits the locking wall 114, the strength is ensured that the wide piece portion 120b can absorb the impact.

The stopper support member 120 is also provided with an insertion hole 124. The insertion hole 124 is a hole recessed from a portion of the outer peripheral surface of the stopper support member 120 that does not interfere with the central hole 121 and the stopper storage portion 123, and is formed from the outer peripheral surface opposite the stopper storage portion 123 in FIG. 3. One end of a one-end latch pin 152 (described later) is inserted into this insertion hole 124, so that the stopper support member 120 supports the one-end latch pin 152.

Next, the stopper member 130 will be described. Figure 5 is a plan view showing the stopper member 130 and the guide groove 145. As shown in Figures 3 to 5, the stopper member 130 is stored in the stopper storage section 123 of the stopper support member 120. This stopper member 130 is stored in the stopper storage section 123 in a state in which it can slide in the centrifugal direction from the storage position.

3, the bottom surface 123a (the inner wall surface on the rotation axis side) of the stopper storage section 123 has a flat portion, and therefore the bottom surface 130a (the surface located on the inner diameter side of the stopper storage section 123) of the stopper member 130 also has a flat portion. A recess (reference number omitted) for attaching a magnet M1 as described later is formed on the bottom surface 130a side of the stopper member 130.

As shown in FIG. 3, when the stopper member 130 is stored in a predetermined position in the stopper storage section 123, the outer peripheral surface of the stopper member 130 (the surface facing away from the radial center) is located on the inner diameter side of the outer peripheral surface of the stopper support member 120 with respect to the center of the rotation axis.

Here, the stopper member 130 is provided with a cylindrical stopper protrusion 131. The stopper protrusion 131 protrudes in the X-axis direction from the surface (front and back surfaces) of the stopper member 130 facing the holding plate 140 toward the holding plate 140. As shown in Figures 3 and 4, the stopper protrusion 131 is provided closer to the axis of the drive shaft 25 (stopper member 130) than the center of the depth direction of the stopper member 130 (the radial direction of the stopper support member 120). The stopper protrusion 131 may be integrally formed with the stopper member 130, but the stopper protrusion 131 may also be formed by providing an attachment hole in the stopper member 130 and fitting an axial member, pin, or the like into the attachment hole.

This stopper protrusion 131 fits into a guide groove 145, which will be described later. As a result, when the rotational positions of the stopper support member 120 and the holding plate 140 change relative to one another, the stopper protrusion 131 slides within the guide groove 145. When the stopper protrusion 131 is positioned in an allowable groove portion 145a, which will be described later, the stopper member 130 can pop out toward the outer diameter side in response to the centrifugal force acting on the stopper member 130 and the pressing force from the second restriction wall 145c1 due to the biasing force of the biasing spring 151.

Here, the outer peripheral surface 132 located at the outermost radial position of the stopper member 130 is formed in an arc shape, similar to the outer peripheral surface of the stopper support member 120 and the outer peripheral surface of the holding plate 140 described above. However, the outer peripheral surface 132 may be formed in a straight line or in another shape. The radial direction of the stopper member 130 described above refers to the direction connecting the center of rotation of the drive shaft 25 and the outer diameter side (the same applies to other parts in this specification).

A magnet M1 is attached to the bottom surface 130a of the stopper member 130. The magnet M1 is a member that generates a magnetic force to return the stopper member 130, which protrudes to the outer diameter side due to the action of centrifugal force, to its original storage position. Specifically, the magnet M1 is arranged to face the bottom surface 123b of the stopper storage section 123 of the stopper support member 120 made of a soft magnetic material. Therefore, the magnet M1 generates a magnetic force between itself and the bottom surface 123b, and the magnetic force increases as the magnet M1 approaches the bottom surface 123b, and the stopper member 130 is pulled back to the storage position.

In addition, when the stopper support member 120 and the stopper member 130 are rotating, the magnet M1 also has the function of suppressing the magnetic force from protruding to the outer diameter side against the centrifugal force until the stopper member 130 reaches a certain rotation speed (set rotation speed). Such set rotation speed can be set to an appropriate rotation speed that is usually used for pulling the chain C1 at high speed. In addition, since the stopper member 130 is held at a predetermined position in the stopper storage section 123 (the position where the bottom surface 130a and the bottom surface 123b contact; storage position) by magnetic force, the sliding contact between the stopper protrusion 131 of the stopper member 130 and the first regulating wall 145b1 of the holding plate 140 can be suppressed when accelerating rapidly from a stopped state, so that the operating value at which the holding plate 140 and the stopper support member 120 rotate relative to each other is stabilized.

Next, the holding plate 140 will be described. In this embodiment, two holding plates 140 with different shapes are provided. In the following description, the holding plate 140 located on the X1 side in FIG. 4 will be referred to as holding plate 140A, and the holding plate 140 located on the X2 side in FIG. 4 will be referred to as holding plate 140B. However, when there is no need to distinguish between the two, they will simply be referred to as holding plates 140. Note that the stopper support member 120 is sandwiched between the holding plates 140A and 140B. The holding plates 140 are connected to each other at a predetermined interval by a connecting member R1. Note that it is preferable that the holding plates 140 are connected to each other firmly so as to be integrated.

Figure 6 is a front view showing the holding plate 140A located on the X1 side. The holding plate 140A is disk-shaped (ring-shaped) and has a center hole 142 in its radial center. The bearing boss portion 122 of the stopper support member 120 is fitted into this center hole 142, so that the holding plate 140 is supported so as to be rotatable coaxially with respect to the stopper support member 120. The distance (i.e., radius) from the center of rotation to the outermost periphery of the holding plate 140A is approximately the same as that to the outermost periphery of the stopper support member 120. However, the radius of either the stopper support member 120 or the holding plate 140A may be set to be larger.

Figure 7 is a front view showing the holding plate 140B located on the X2 side. This holding plate 140B has a recessed portion extending from the outer diameter side to the inner diameter side by punching or bending multiple circular ring-shaped portions (two portions in Figure 7).

One of these recessed portions is provided with a locking protrusion 143 that is raised from the plate surface of the holding plate 140B. This locking protrusion 143 is a portion that abuts against the side surface 120b1 of the wide piece portion 120b of the stopper support member 120, and due to this abutment, even if the stopper support member 120 is pulled by the biasing spring 151, it is in a state where it does not rotate any further. In other words, the locking protrusion 143 regulates the rotational position of the stopper support member 120 in the winding direction relative to the holding plate 140B. Therefore, it is possible to suppress the stopper protrusion 131 from receiving the biasing force from the biasing unit 150 at the terminal end of the clearance groove portion 145b in the second rotation direction. Therefore, it is possible to reduce the influence of the frictional force caused by the biasing force from the biasing unit 150 generated between the stopper member 130 and the side wall 123a on the behavior of the stopper member 130, and to stabilize the operation of the rotation lock device 100.

The side of the locking protrusion 143 abuts against the side of the wide piece portion 120b. The boundary between the locking protrusion 143 and the plate surface is not aligned along the radial direction of the retaining plate 140B, but is set at a predetermined angle relative to the radial direction. This prevents the locking protrusion 143 from deforming and changing the bending angle relative to the plate surface when the wide piece portion 120b collides against the locking protrusion 143.

In addition, in the same manner as described above, the other of the recessed portions has a spring receiving protrusion 144 that is raised from the plate surface of the holding plate 140B. As shown in Fig. 3, the spring receiving protrusion 144 is disposed on the outer diameter side of the holding plate 140B relative to the biasing spring 151, and prevents the biasing spring 151 from falling toward the outer diameter side due to centrifugal force when the holding plate 140 rotates.

The holding plate 140 is also provided with a guide groove 145. As shown in Figs. 5 to 7, the guide groove 145 is a portion into which the stopper protrusion 131 of the stopper member 130 enters to guide the movement of the stopper protrusion 131, and its appearance is a shape in which a groove extending long in an arc shape is added to the radial center side of a substantially triangular part. Specifically, the guide groove 145 is provided with a substantially triangular holding protrusion 146 as shown in Figs. 5 to 7, and the guide groove 145 is provided with an allowance groove portion 145a, a clearance groove portion 145b, and a return restriction groove portion 145c due to the insertion. In addition to these groove portions, the guide groove 145 is also provided with a movement restriction groove portion 145d.

The tolerance groove 145a is a groove that allows the stopper protrusion 131 to move in the radial direction. Therefore, the inner wall 145a1 located below the tolerance groove 145a in Figures 5 to 7 is provided so as to be parallel to the radial direction (the direction of one radial line extending from the center of the central hole 142). The width of the tolerance groove 145a is determined by the distance between the protrusion tip 146a of the holding protrusion 146 that protrudes toward the innermost wall 145a1 and the above-mentioned inner wall 145a1.

The clearance groove 145b is a groove recessed from the protruding tip 146a in the circumferential direction away from the tolerance groove 145a (to the right in Figs. 5 to 7). This clearance groove 145b allows the stopper protrusion 131 to be positioned with some play. The clearance groove 145b is provided on the side (the other end) furthest from the tolerance groove 145a with a movement restriction groove 145d, which will be described later.

In addition, although an R-shaped portion (rounded corner portion) exists at the end of the clearance groove portion 145b on the tolerance groove portion 145a side, the radius of the R-shaped portion is set to a dimension equivalent to the radius of the stopper protrusion 131. Here, if the radius of the R-shaped portion is larger than the radius of the stopper protrusion 131, when the stopper protrusion 131 collides with this R-shaped portion, a force that moves the stopper protrusion 131 to the outer diameter side is applied. However, by setting the radius of the R-shaped portion to a dimension equivalent to the radius of the stopper protrusion 131, it is possible to prevent the stopper protrusion 131 from applying a force that moves the stopper protrusion 131 to the outer diameter side when the stopper protrusion 131 collides with this R-shaped portion. The radius of the R-shaped portion may be set to a dimension smaller than the radius of the stopper protrusion 131.

Here, the inner wall (first restriction wall 145b1) on the outer diameter side of the clearance groove portion 145b is a wall surface that engages with the stopper protrusion 131 to hold the stopper member 130 in a predetermined position of the stopper support member 120, and is an arc-shaped wall surface concentric with the center hole 142. Note that, when the stopper protrusion 131 is stored in this clearance groove portion 145b, the outer diameter side of the stopper member 130 is stored in the stopper storage portion 123 in a state where it does not protrude outer diameter beyond the outer circumferential surface of the stopper support member 120.

Here, the circumferential length of the clearance groove portion 145b is formed to be longer than the length determined by the angle γ described below. That is, when the ratchet wheel 80 is interrupted during the winding operation, it rotates freely in the winding down direction by a maximum angle (pitch angle) obtained by dividing one revolution by the number of teeth. This angle is called angle γ (not shown). In this case, it is preferable that the rotation lock device 100 also operates with a delay of an angle greater than angle γ. For this reason, in the stored state of the stopper member 130, the circumferential length of the clearance groove portion 145b into which the stopper protrusion 131 enters is made longer than at least angle γ. It is preferable to maintain the hold of the stopper member 130 until the holding plate 140 rotates relative to the stopper support member 120 by angle γ or more in the second rotation direction opposite to the winding down direction with respect to the drive shaft 25 and the stopper support member 120.

In this embodiment, the clearance groove portion 145b is sufficiently longer than the angle γ. If the length of the clearance groove portion 145b is short, the rotation lock device 100 is likely to operate during the free rotation operation of quickly pulling out the chain C1 in the lowering direction after switching the switch knob 45 to the neutral position and operating the free rotation grip 60 to set the free rotation mode, and the convenience of pulling out the chain C1 is reduced. Therefore, the length of the clearance groove portion 145b is made sufficiently longer than the angle γ so that the rotation lock device 100 does not immediately operate during the free rotation operation of manually pulling out the chain C1 after switching the switch knob 45 to the neutral position to set the free rotation mode. This prevents the rotation lock device 100 from operating and becoming in a rotation lock state during the free rotation operation as described above.

The return restriction groove 145c is a groove recessed in the circumferential direction (upward in Figs. 5 to 7) away from the allowance groove 145a. This return restriction groove 145c allows the stopper protrusion 131 to be positioned with some play. However, the return restriction groove 145c is provided with a second restriction wall 145c1. This second restriction wall 145c1 engages with the stopper protrusion 131, so that the outer diameter side of the stopper member 130 is maintained in a state protruding from the outer circumferential surface of the stopper support member 120. In other words, the second restriction wall 145c1 is a wall surface for restricting the stopper member 130 from being stored in the stopper storage portion 123.

The second restricting wall 145c1 is inclined so as to gradually approach the inner wall 145a1 as it approaches the inner diameter side, and is in contact with the holding protrusion 146. Therefore, even if the rotational acceleration of the drive shaft 25 in the first rotation direction decreases after the stopper member 130 slides in the centrifugal direction from a predetermined position and the stopper protrusion 131 passes the protrusion tip 146a, the stopper member 130 reliably engages with the locking wall 114 by engaging with the second restricting wall 145c1, and maintains the engagement while the load in the first rotation direction continues on the drive shaft 25. On the other hand, when the stopper protrusion 131 is inserted in the return restricting groove portion 145c, the stopper support member 120 and the stopper member 130 are rotated relative to the holding plate 140, and the stopper protrusion 131 moves toward the allowable groove portion 145a, and the engagement with the second restricting wall 145c1 is released. This allows the stopper member 130 to move toward the inner diameter side of the stopper accommodating portion 123 .

The movement restricting groove 145d is a groove into which the stopper protrusion 131 attached to the stopper member 130 fits when the stopper support member 120 and the holding plate 140 are rotated at high speed in the winding direction. The movement restricting groove 145d is provided with a third restricting wall 145d1 and a return guide wall 145d2.

The third restricting wall 145d1 is a wall surface against which the stopper protrusion 131 collides. That is, the third restricting wall 145d1 is a wall surface that restricts the rotation of the holding plate 140 in the clockwise direction in FIG. 5 to FIG. 7 relative to the stopper member 130 by abutting against the stopper protrusion 131 of the stopper member 130 that has moved into the movement restricting groove portion 145d. In detail, for example, when a load is applied to the lower hook (not shown), the load sheave 20 around which the chain C1 is wound rotates in the winding direction by pulling the side opposite the lower hook of the slackened chain C1 with a hand, and the drive shaft 25 and the stopper support member 120 rotate at high speed integrally via the reduction gear 30, and the holding plate 140 also rotates at high speed in accordance with the high speed rotation. At this time, the stopper member 130 moves to the outer diameter side due to centrifugal force, so that the stopper protrusion 131 enters the movement restricting groove portion 145d.

In this state, when the slack in the chain C1 is eliminated, the rotation of the drive shaft 25 and the stopper support member 120 comes to an abrupt halt together with the load sheave 20. At this time, even if the holding plate 140 attempts to rotate in the winding direction due to inertia, the stopper protrusion 131 abuts against the third restricting wall 145d1, thereby preventing the holding plate 140 from rotating due to inertia.

Therefore, the third restricting wall 145d1 is provided in a shape that prevents the stopper protrusion 131 from moving toward the inner diameter side even when the stopper protrusion 131 is pressed. For example, the third restricting wall 145d1 may be formed so as to extend along the radial direction. However, the shape of the third restricting wall 145d1 is not limited to this shape, and the third restricting wall 145d1 may be formed, for example, so that a concave pocket portion is present slightly to the left (counterclockwise side) in FIG. 5, or so that the third restricting wall 145d1 is inclined to the left (counterclockwise side) as it approaches the radial direction.

The return guide wall 145d2 is a wall surface on which the stopper projection 131 slides, similar to the third restricting wall 145d1, and prevents the stopper member 130 from engaging with the stopper locking member 110, and returns the stopper member 130 to a predetermined storage position on the inner diameter side. Specifically, the return guide wall 145d2 is a wall surface that is inclined toward the center in the radial direction as it moves to the right (clockwise direction) in Figures 5 to 7. Therefore, the return guide wall 145d2 can be used to return the stopper member 130 to the storage position of the stopper storage section 123.

Regarding the return of the stopper member 130, when the retaining plate 140 is in a positional relationship where the locking protrusion 143 abuts against the side surface of the stopper locking member 110 and is rotating at a high speed above a predetermined speed, the stopper member 130 moves due to centrifugal force, and the stopper protrusion 131 moves into the movement restriction groove portion 145d. Consider a case where the rotation of the drive shaft 25 and the stopper support member 120 slows down and stops in this state. Before deceleration, the pulling force of the biasing spring 151 acts between the stopper support member 120 and the retaining plate 140, so that the retaining plate 140 tries to rotate leftward (counterclockwise) relative to the stopper support member 120 and the stopper member 130 in Figures 5 to 7, but the rotation is restricted by the abutment of the stopper locking member 110 and the locking protrusion 143. When the holding plate 140 starts to decelerate while rotating at high speed in the winding direction, it rotates in the winding direction relative to the stopper support member 120 and the stopper member 130 against the biasing force of the biasing spring 151 until it abuts against the third restriction wall 145d1, as shown in Fig. 11. From this state, while the deceleration ends and the stopper plate 140 stops, the biasing force of the biasing spring 151 causes the stopper protrusion 131 to slide against the return guide wall 145d2, but the inclination of the return guide wall 145d2 pushes the stopper member 130 back toward the specified storage position. When the magnet M1 slides a specified distance and approaches the bottom surface 123b of the stopper storage section 123, the magnetic force between the magnet M1 and the bottom surface 123b causes the stopper member 130 to return to the storage position.

Even when the stopper projection 131 is located at the outermost radial position within the movement restriction groove 145d, the outer peripheral surface 132 of the stopper member 130 is stored in the stopper storage portion 123 without protruding further outward than the outer peripheral surface of the stopper support member 120. In this state, the stopper member 130 does not collide with the locking wall 114, and the stopper support member 120, the stopper member 130, and the retaining plate 140 can rotate together.

By the way, the stopper member 130, two holding plates 140, and the urging unit 150 are assembled to the stopper support member 120, the two holding plates 140 are connected at a predetermined interval by the connecting member R1 (see FIG. 4), the stopper protrusion 131 is regulated by the inner wall of the guide groove 145, and the stopper member 130 is held at a predetermined position in the stopper storage section 123 of the stopper support member 120, so that it can be made into one unit. By making it into one unit in this way, it is possible to easily and reliably perform the work of assembling it to the drive shaft 25 and removing and replacing it during maintenance. In particular, it is possible to check and adjust the operation of the above-mentioned one unit before assembling it to the lever hoist 10 (hoisting machine). In addition, even if a large load acts on the stopper member 130, the pair of holding plates 140 can reliably hold the stopper member 130 in the stopper storage section 123 of the stopper support member 120.

In this embodiment, the connecting member R1 is composed of a rivet and a collar (spacer). That is, a collar is placed between a pair of holding plates 140, and a rivet is inserted through a hole 141 formed in the holding plate 140 and the collar. The other end of the rivet is then plastically deformed to connect the pair of holding plates 140 while maintaining a predetermined distance.

Next, the biasing unit 150 will be described. As shown in Figures 3 and 4, the biasing unit 150 has a biasing spring 151, a one-end latch pin 152, and a connecting member R1 corresponding to the other-end latch pin. Of these, the biasing spring 151 is a tension spring in this embodiment. The configuration of the biasing unit 150 may include a tension spring, a compression spring, or a torsion spring, as long as it is configured to rotate the holding plate 140 in one rotation direction (lowering direction; first rotation direction), which is the counterclockwise direction in Figure 3, relative to the stopper support member 120.

As described above, the one-end latch pin 152 is attached by being inserted into the insertion hole 124 of the stopper support member 120. The insertion hole 124 is a screw hole, and the male thread of the one-end latch pin 152 is screwed in to attach it. One end of the biasing spring 161 is hooked onto this one-end latch pin 152. The connecting member R1 also serves as the other-end latch pin. That is, the other end of the biasing spring 151 is hooked onto the connecting member R1 inserted into the hole portion 141.

Here, the point of action at which the spring 151 of the one-end latch pin 152 is hung and the point of action at which the spring 151 of the connecting member R1 corresponding to the other-end latch pin is hung are different from each other by a predetermined angle θ with respect to the center of rotation. Therefore, the spring 151 applies a force so that this angle θ becomes small.

<About action>
Regarding the rotation lock (load drop prevention) device 100 configured as described above, consider a case where, during a hoisting operation of the lever hoist 10, the brake device 70 is broken, for example, and the drive shaft 25 begins to accelerate its rotation in the lowering direction due to tension applied to the chain C1 due to the hanging load, etc.

Figure 8 shows the configuration of the lever hoist 10 shown in Figure 1 near the rotation lock (load fall prevention) device 100, and also shows the positional relationship of each part before the rotation lock (load fall prevention) device 100 is activated. Figure 9 shows the positional relationship of each part when the holding plate 140 rotates relative to the stopper support member 120 and the holding plate 140 from the state shown in Figure 8, and the allowable groove portion 145a reaches the position of the stopper protrusion 131. Figure 10 shows the positional relationship of each part when the stopper member 130 protrudes outward from the state shown in Figure 9, and the stopper protrusion 131 is located in the return restriction groove portion 145c.

First, when the braking force is lost while a load is suspended, the drive shaft 25 and the stopper support member 120 together with the stopper member 130 suddenly increase their rotation speed in one rotation direction (lowering direction), which is the counterclockwise direction in FIG. 8. At this time, the biasing force of the biasing spring 151 acts to make the holding plate 140 follow the rotation of the stopper member 130 with the stopper protrusion 131 of the stopper member 130 positioned at the very end of the clearance groove portion 145b (the end on the side away from the allowable groove portion 145a). However, when the inertial force acting on the holding plate 140 exceeds the biasing force of the biasing spring 151, the holding plate 140 is left behind, and the stopper protrusion 131 moves away from the end of the clearance groove portion 145b on the movement restriction groove portion 145d side. Furthermore, when the drive shaft 25 accelerates and rotates together with the stopper support member 120 and the stopper member 130 with an acceleration in a direction in which the stopper protrusion 131 moves away (cannot follow) from the end of the gap groove portion 145b on the movement restriction groove portion 145d side, the force of inertia acting on the retaining plate 140 causes the biasing spring 151 to extend, and the stopper protrusion 131 of the stopper member 130 moves within the gap groove portion 145b toward the tolerance groove portion 145a.

Furthermore, even if the stopper member 130 attempts to pop out toward the outer diameter side due to the centrifugal force generated by the rotation of the stopper support member 120 and the stopper member 130, the stopper protrusion 131 is restricted by the first restricting wall 145b1 until the stopper protrusion 131 reaches the tolerance groove portion 145a, thereby restricting the stopper member 130 from popping out toward the outer diameter side.

9, the stopper member 130 can jump out to the outer diameter side. That is, the stopper member 130, whose engagement (holding) state between the stopper member 131 and the first restricting wall 145b1 is released, jumps out from the stopper storage portion 123 to the outer diameter side by centrifugal force. However, the jump out to the outer diameter side is within the range up to the outermost periphery side of the guide groove 145. On the other hand, even if the rotational acceleration in the first rotation direction of the drive shaft 25 decreases after the stopper member 130 slides in the centrifugal direction from a predetermined position and the stopper member 131 passes the protruding portion tip portion 146a, the stopper member 130 is pressed by the second restricting wall 145c1 by the biasing force of the biasing spring 151. This pressure causes the stopper member 130 to protrude to a position where it positively engages with the locking wall 114, and this engagement is maintained as long as the load in the first rotational direction continues on the drive shaft 25.

When the stopper member 130 protruding from the stopper storage section 123 continues to rotate in one rotation direction (lowering direction), which is the counterclockwise direction, it collides with the locking wall 114 of the stopper locking member 110, as shown in Figure 10. This stops the rotation of the stopper support member 120 and the drive shaft 25 in one rotation direction (lowering direction), and stops the fall of the load.

After the stopper member 130 collides with the locking wall 114, the stopper protrusion 131 enters the return restriction groove 145c. As a result, after the drive shaft 25 stops, the stopper protrusion 131 receives a counterclockwise force from the second restriction wall 145c1 due to the biasing force of the biasing spring 151, so that the state in which the stopper protrusion 131 enters the return restriction groove 145c is maintained. At this time, even if the stopper member 130 tries to inadvertently return to the stopper storage portion 123, the stopper protrusion 131 maintains its engagement with the second restriction wall 145c1, thereby restricting the stopper member 130 from returning to the stopper storage portion 123. Therefore, the rotation stop state of the drive shaft 25 is maintained. In other words, the load is prevented from starting to fall again.

Next, consider the free-spinning mode, in which the chain C1 can be pulled by hand in the hoisting down direction when the brake device 70 is operating normally. The lever hoist 10 has the free-spinning function described above so that the length of the chain C1 can be adjusted when attaching the hook to an object. Specifically, the brake device 70 has a function of releasing the brake by using the action of an idling spring (not shown) on the female thread member 35. In the free-spinning mode, the length of the chain C1 can be adjusted at a faster speed than when the operation lever 50 is operated. There are two types of free-spinning mode for the lever hoist: an automatic free-spinning mode, in which the switch knob 45 is simply set to neutral in an unloaded state, and a lever hoist 10 shown in Figures 1 and 2, in which the switch knob 45 is set to neutral and then the free-spinning grip 60 is operated in a specified manner to switch to the free-spinning mode. In this embodiment, the latter switching knob 45 is operated to neutral, and then the free rotation grip 60 is operated in a predetermined manner to switch to the free rotation mode, but a detailed description of this will be omitted.

In this free-spinning mode, the braking force of the brake device 70 is temporarily disabled. However, for safety reasons, the brake device 70 operates to stop the rotation of the drive shaft 25 when a tension equal to or greater than a predetermined value acts on the chain C1 in the lowering direction. On the other hand, the brake device 70 having the ratchet wheel 80 used in many lever hoists such as the lever hoist 10 does not brake in the hoisting direction, so it is possible to adjust the length of the chain C1 at a speed faster than the speed of hoisting with the operating lever 50 without switching to the free-spinning mode. In such a situation, it is better for the rotation lock (load drop prevention) device 100 to operate as little as possible in the hoisting direction (the other rotation direction) to improve workability.

The length of the chain C1 can be adjusted not only by unwinding the chain C1 in the lowering direction, but also by winding up the slackened chain C1. As mentioned above, the lowering direction is adjusted by switching to the free rotation mode, but if the chain C1 is pulled with a tension greater than a certain level, the brake device 70 is activated. On the other hand, adjustment in the winding direction is performed by the operator pulling the unloaded part of the chain C1. In this case, the load sheave 20 rotates in the winding direction, and the drive shaft 25, the stopper support member 120, and the stopper member 130 also rotate in the winding direction. At this time, the inertial force acting on the holding plate 140 acts in a direction that presses the stopper protrusion 131 against the end of the clearance groove portion 145b on the movement restriction groove portion 145d side. In this state, even if the speed at which the chain C1 is pulled in the winding direction increases and the centrifugal force acting on the stopper member 130 gradually increases, when the stopper protrusion 131 of the stopper member 130 is positioned in the clearance groove portion 145b including the movement restricting groove portion 145d, the stopper member 130 does not engage with the stopper engaging member 110, and the rotation lock by the rotation lock device 100 does not work. Below a predetermined rotation speed, the stopper member 130 does not jump out to the outer diameter side in the radial direction due to the holding force caused by the magnetic force between the magnet M1 and the bottom surface 123b of the stopper housing portion 123. Therefore, below the predetermined rotation speed, the stopper protrusion 131 does not enter the inside of the movement restricting groove portion 145d.

However, when the rotational speed exceeds a certain value, the centrifugal force acting on the stopper member 130 becomes greater than the magnetic holding force between the magnet M1 and the bottom surface 123b of the stopper storage section 123, so that the stopper member 130 moves outward and the stopper protrusion 131 enters the movement restriction groove section 145d.

11 and 12, the stopper protrusion 131 is located at the outermost side of the movement restriction groove portion 145d and abuts against the third restriction wall 145d1. In the state shown in FIG. 11, the outer peripheral surface 132 of the stopper member 130 is located at a position equal to or lower than the outer peripheral surface of the stopper support member 120 in the radial direction.

Here, when the slack in the chain C1 is eliminated, the chain C1 between the load and the lever hoist 10 is in a taut state, but if the load is too light to be lifted, the chain C1 cannot be wound up, and the rotation of the drive shaft 25 and the stopper support member 120 (stopper member 130) stops suddenly. However, the holding plate 140 tries to rotate in the winding direction due to inertia, but as shown in Figures 11 and 12, the stopper protrusion 131 abuts (collides) against the third restricting wall 145d1, preventing the holding plate 140 from rotating due to inertia. Note that Figure 11 is a transparent diagram showing the positional relationship of each part in a state in which the holding plate 140 rotates slightly in the winding direction relative to the state shown in Figure 8 after the stopper protrusion 131 enters the movement restricting groove portion 145d, and the stopper protrusion 131 abuts against the third restricting wall 145d1.

Therefore, the stopper protrusion 131 can be prevented from moving inside the clearance groove portion 145b toward the tolerance groove portion 145a. Therefore, by the stopper protrusion 131 moving toward the outer diameter side inside the tolerance groove portion 145a, the stopper member 130 can be prevented from protruding outward beyond the outer circumferential surface of the stopper support member 120 even during winding.

When the rotation in the winding direction stops, the stopper member 130 returns to the storage position of the stopper storage section 123. That is, the pulling force of the biasing spring 151 acts between the stopper support member 120 and the holding plate 140. Therefore, the stopper support member 120 and the stopper member 130 try to rotate to the right (clockwise direction) relative to the holding plate 140 in Figs. 11 and 12. Therefore, the stopper protrusion 131 slides along the return guide wall 145d2 due to the action of the pulling force of the biasing spring 151, as shown in Fig. 13. Then, when the magnet M1 slides a predetermined amount and approaches the bottom surface 123b of the stopper storage section 123, the magnetic force between the magnet M1 and the bottom surface 123b becomes large, and the stopper member 130 returns to the storage position due to the action of the increased magnetic force.

Even when the stopper member 130 returns to the stored position, the tension force of the biasing spring 151 continues to act between the stopper support member 120 and the retaining plate 140, and while this tension force is acting, the locking protrusion 143 abuts against the side of the wide piece portion 120b of the stopper support member 120. Therefore, with the stopper protrusion 131 biased toward the clockwise end side of the clearance groove portion 145b, it is possible to prevent the stopper member 130 from being pressed against the side wall 123a of the stopper support member 120. In addition, the stopper member 130 is attracted to and held on the bottom surface 123b of the stopper storage section 123 by the magnetic force of the magnet M1. Therefore, even if the holding plate rotates in the winding direction relative to the stopper support member and the stopper protrusion 131 is positioned in the allowable groove section 145a, the stopper member 130 is stored in a predetermined position in the stopper storage section, and the rotation lock by the rotation lock device 100 will not be activated unless a force greater than the magnetic attraction force acts.

Next, consider the case where the worker pulls the chain C1 in the lowering direction. At this time, the load sheave 20 rotates in the lowering direction, and the drive shaft 25, the stopper support member 120, and the stopper member 130 also rotate in the lowering direction. At this time, due to the rotational acceleration of the stopper support member 120 and the stopper member 130, the holding plate 140 rotates relatively against the biasing force of the biasing spring 151 so as to be left behind, and the stopper protrusion 131 may move away from the end of the clearance groove portion 145b (the end on the side away from the allowable groove portion 145a). In this case, if the length of the clearance groove portion 145b is short, the stopper protrusion 131 reaches the allowable groove portion 145a relatively easily, and then the stopper member 130 protrudes to the outer diameter side, resulting in a locked state in which the locking wall 114 and the stopper member 130 collide. In that case, the worker's work of pulling the chain C1 in the lowering direction is interrupted, and the locked state needs to be released, which deteriorates workability.

However, in this embodiment, the length of the clearance groove portion 145b is sufficiently longer than the above angle γ, and is set to such an extent that the stopper protrusion 131 cannot reach the allowable groove portion 145a even if it moves slightly within the clearance groove portion 145b at the rotation acceleration of the extent to which the operator pulls the chain C1 in the lowering direction. Therefore, the operator can continue to pull the chain C1 in the lowering direction without interruption. The length of the clearance groove portion 145b is set so that if the drive shaft 25 rotates suddenly in the lowering direction in the free rotation mode, the brake device 70, which is temporarily released by the free rotation mode, brakes the rotation of the drive shaft 25 before the rotation lock device 100.

<About the effects>
The rotation lock (anti-falling of cargo) device 100 configured as described above comprises a stopper support member 120 that is attached to the drive shaft 25 (shaft-shaped member) and rotates integrally with the drive shaft 25 (shaft-shaped member), a stopper member 130 that is supported by the stopper support member 120 in a state in which it can slide outward from the axial center side of the drive shaft 25 (shaft-shaped member), a holding plate 140 that is disk-shaped and rotatable relative to the stopper support member 120 and holds the stopper member 130 at a predetermined position on the stopper support member 120, a biasing spring 151 (biasing means) that biases the holding plate 140 toward a first rotation direction, which is one rotation direction, relative to the stopper support member 120, and a stopper engagement member 110 (stopper engagement means) that engages with the stopper member 130 to stop the rotation of the drive shaft 25 (shaft-shaped member). In addition, the stopper member 130 has a stopper protrusion 131 that protrudes toward the holding plate 140, and the holding plate 140 has a guide groove 145 that engages with the stopper protrusion 131 and holds the stopper member 130 at a predetermined position in the radial direction of the stopper support member 120, and the guide groove 145 has a first regulating wall 145b1 with which the stopper member 130 engages at a predetermined position in the radial direction and which is formed as an arc concentric with the drive shaft 25 (shaft-shaped member), and a second regulating wall 145c1 with which the stopper member 130 engages at a position where it protrudes outward from the predetermined position in the radial direction, and the second regulating wall 145c1 is provided on one side of the guide groove 145 in the circumferential direction.

In addition, when the drive shaft 25 (shaft-shaped member) accelerates its rotation toward the first rotation direction, the stopper support member 120 and the holding plate 140 rotate relatively against the biasing force of the biasing spring 151 (biasing means), and when the stopper protrusion 131 is disengaged from the first restricting wall 145b1, the stopper member 130 protrudes from a predetermined position to a position where it engages with the stopper locking member 110 (stopper locking means), stopping the rotation of the drive shaft 25 (shaft-shaped member). At the same time, a third restricting wall 145d1 is provided on the other circumferential side of the guide groove 145, which engages with the stopper member 130 at a position where the stopper member 130 protrudes from a predetermined position in the radial direction to the outer diameter side, thereby preventing the holding plate 140 from rotating relatively to the stopper support member 120 toward the second rotation direction opposite to the first rotation direction. When the stopper projection 131 is engaged with the third restricting wall 145d1, the stopper member 130 and the stopper locking member 110 (stopper locking means) are located at a non-locking position.

With this configuration, when an operator pulls the slack chain C1 in the winding direction at high speed, and the centrifugal force acting on the stopper member 130 causes the stopper member 130 to jump outward, the slack in the chain C1 is eliminated, and the rotation of the drive shaft 25 and the stopper support member 120 (stopper member 130) suddenly stops. The holding plate 140, however, tries to rotate in the winding direction due to inertia when the stopper protrusion 131 abuts (collides) against the third restricting wall 145d1. This prevents the stopper protrusion 131 from moving in the second rotation direction within the guide groove 145. Furthermore, when the stopper protrusion 131 engages with the third regulating wall 145d1, the stopper member 130 and the stopper engaging member 110 (stopper engaging means) are positioned in a non-engaging position, so that the stopper member 130 can be prevented from protruding outward beyond the outer circumferential surface of the stopper support member 120 even during winding.

This prevents the rotation lock device 100 from being unintentionally activated even when the load has not actually fallen (there is an operation in the hoisting direction), causing the drive shaft 25 (shaft-shaped member) to become unable to rotate, thereby preventing the trouble of resetting the rotation lock device 100.

In addition, when the drive shaft 25 (shaft-shaped member) exceeds a predetermined acceleration in one rotation direction in the hoisting down direction, the rotation lock (load drop prevention) device 100 is activated to stop the rotation. Furthermore, when the drive shaft 25 (shaft-shaped member) accelerates and rotates in the first rotation direction, which is one rotation direction, the rotation lock (load drop prevention) device 100 can be set to operate at a slower rotation speed than when rotating in the other rotation direction due to the synergistic effect of the acceleration and rotation speed. In addition, even if the brake device 70 breaks down in a drive device in which the load only works in one direction, such as a hoist or lifting device, the rotation of the rotating member for lifting or lifting can be immediately stopped, preventing accidents due to load dropping, etc.

In addition, in this embodiment, a return guide wall 145d2 for returning the stopper member 130 to a predetermined position on the axial center side is provided on the other circumferential side of the third restricting wall 145d1, and the return guide wall 145d2 is inclined toward the inner diameter side as it moves from one circumferential side to the other side.

This configuration makes it easy to return the stopper member 130 to a predetermined position (storage position) of the stopper support member 120. That is, the tensile force of the biasing spring 151 (biasing means) acts between the stopper support member 120 and the holding plate 140. Therefore, the stopper support member 120 and the stopper member 130 tend to rotate to the right (clockwise direction) relative to the holding plate 140 in Figs. 5 to 7, so that the stopper protrusion 131 slides along the return guide wall 145d2 to move the stopper member 130 toward a predetermined position (storage position) of the stopper support member 120. This makes it easy to return the stopper member 130 to a predetermined position (storage position) of the stopper support member 120.

In the present embodiment, the third restricting wall 145d1 and the return guide wall 145d2 are provided on the inner wall of the movement restricting groove portion 145d. Therefore, when processing the holding plate 140, the third restricting wall 145d1 and the return guide wall 145d2 can be formed at the same time, for example, by pressing, etc., and the processing process can be simplified.

In this embodiment, the stopper support member 120 is made of a soft magnetic material, and a magnet M1 is attached to the radially inner side of the stopper member 130. Therefore, the magnetic force of the magnet M1 can assist the stopper member 130 in returning to a predetermined position (storage position).

In addition, in this embodiment, the holding plate 140 is provided with an engagement protrusion 143 (protrusion means) that protrudes from the front or back surface of the holding plate 140, and the engagement protrusion 143 (protrusion means) is positioned at a position where it abuts against the side surface 120b1 of the stopper support member 120 before or at the same time that the stopper protrusion 131 abuts against the end of the guide groove 145 opposite the first rotation direction when the holding plate 140 is urged in the first rotation direction by the urging spring 151 (urging means).

Therefore, by the locking protrusion 143 (protruding means) abutting against the side surface 120b1 of the stopper support member 120, it is possible to prevent the urging force from continuing to act on the stopper protrusion 131. It is also possible to prevent the stopper member 130 from being pressed against the internal side wall of the stopper storage portion 123. This makes it possible to prevent the frictional force between the stopper member 130 and the internal side wall of the stopper storage portion 123 from hindering the stopper member 130 from returning to the specified position (storage position).

In addition, in this embodiment, the retaining plate 140 is provided with a spring receiving protrusion 144 which is formed by bending a portion of the retaining plate 140 and is positioned on the outer diameter side of the retaining plate 140 relative to the biasing spring 151 (biasing means). The spring receiving protrusion 144 prevents the biasing spring 151 (biasing means) from falling off to the outer diameter side due to the centrifugal force generated when the retaining plate 140 rotates.

In this way, by arranging the spring receiving protrusion 144 on the outer diameter side of the retaining plate 140B rather than the biasing spring 151 (biasing means), it is possible to prevent the biasing spring 151 from falling toward the outer diameter side due to centrifugal force when the retaining plate 140 rotates.

<Modification>
Although the embodiments of the present invention have been described above, the present invention can be modified in various ways, which will be described below.

In each of the above-described embodiments, the rotation lock (load drop prevention) device 100 is described as being applied to a lever hoist 10. However, the above-described rotation lock (load drop prevention) device may also be applied to hoists other than lever hoists, such as chain blocks, or to lifting devices in which the load direction is constant, similar to hoisting devices.

In the above embodiment, the magnet M1 is attached to the bottom surface 130a of the stopper member 130. However, the magnet may be attached to the bottom surface 123b of the stopper storage section 123, or may be attached to both the bottom surface 130a of the stopper member 130 and the bottom surface 123b of the stopper storage section 123.

An example of such a configuration is shown in Figure 14. In Figure 14, a recess (reference number omitted) is provided on the bottom surface 130a side of the stopper member 130, and a magnet M1 is disposed in the recess. In addition, a recess (reference number omitted) is also provided on the bottom surface 123b side of the stopper support member 120, and a magnet M2 is disposed in the recess. In this case, the opposing magnetic poles of magnets M1 and M2 are different so that magnets M1 and M2 are attracted to each other by magnetic force.

Here, the adhesive force when magnets M1 and M2 are in contact and attracted to each other as shown in FIG. 14 (i.e., when the distance between magnets M1 and M2 = 0) is equivalent to the adhesive force when magnet M1 is in contact with and attracted to the bottom surface 123b of the stopper support member 120 made of an iron-based metal as shown in FIG. 5 (i.e., when the distance between magnet M1 and bottom surface 123b = 0).

Here, as shown in FIG. 15(A), the attractive force when the magnet M1 and the bottom surface 123b of the stopper support member 120 face each other at a distance Y is compared with the attractive force when the magnets M1 and M2 face each other at the same distance Y. In this case, since the attractive force of a magnet is inversely proportional to the square of the distance, the attractive force when the magnet M1 and the bottom surface 123b of the stopper support member 120 face each other at a distance Y is about four times as large as the attractive force when the magnet M1 and the bottom surface 123b of the stopper support member 120 face each other at a distance Y. In other words, the attractive force is equal to the attractive force when the magnet M1 and the bottom surface 123b of the stopper support member 120 face each other at a distance Y/2 as shown in FIG. 15(A).

In this way, magnets M1 and M2 that exert a magnetic force in a direction that attracts them to each other are attached to both the radially inner diameter side of the stopper member 130 and the opposing portion of the stopper support member 120. Therefore, compared to the configuration in which the magnet M1 and the bottom surface 123b of the stopper support member 120 face each other as shown in Figure 5, it is possible to strengthen the magnetic attraction force that acts when the magnets M1 and M2 separate from each other, and when the stopper member 130 protrudes to the outer diameter side, even if a certain degree of frictional resistance is generated due to, for example, a foreign object, the stopper member 130 can be easily returned to a predetermined position (storage position).

6 and 7, the radial dimension of the movement restriction groove 145d is smaller than that of the allowance groove 145a in the holding plate 140. Therefore, when the stopper member 130 is positioned in the allowance groove 145a, the amount of protrusion of the stopper member 130 toward the outer diameter side is smaller than when the stopper member 130 is positioned in the movement restriction groove 145d. Therefore, when the configuration in which the magnets M1 and M2 are arranged as described above is adopted, the stopper member 130 can be easily returned to the predetermined position (storage position) compared to the configuration in which the magnet M1 and the bottom surface 123b of the stopper support member 120 face each other.

Although the rotation lock (load fall prevention) device 100 is illustrated as being placed on the drive shaft of the hoist, its attachment position is not limited to the drive shaft, and the rotation lock (load fall prevention) device 100 can be placed on an axial member that rotates integrally with the target rotating member, such as the shaft of a load sheave or winding drum. By doing so, it is possible to prevent the load from falling even if the reduction mechanism or the like is damaged.

Although not shown in the figure, a guide groove may be provided on the stopper member 130 side, and a guide pin that engages with the guide groove may be provided on the retaining plate 140 side.

In addition, it is preferable that two holding plates 140 are arranged to sandwich the stopper support member 120, but it is also possible to configure only one holding plate 140 to be arranged adjacent to the stopper support member 120.

In addition, the rotation of the holding plate 140 due to the biasing force of the biasing unit 160 is restricted by bending a part of the holding plate 140B to provide a locking protrusion 143 corresponding to the protruding means, which abuts against the side surface 120b1 of the stopper support member 120. However, the protruding means may be a separate member attached to the holding plate 140, such as a connecting member R1 such as a rivet.

In addition, a magnet M1 is provided to pull the stopper member 130 back to a position in contact with the bottom surface 123b when the stopper protrusion 131 is positioned in the movement restriction groove portion 145d, but it is also possible to form a long, gently sloping portion of the return guide wall so that the stopper member 130 is pulled back by the biasing force of the biasing unit 160.

In addition, the movement restricting groove portion 145d having the third restricting wall 145d1 is provided at the other end of the clearance groove portion, but it may be located not only at the end but also in the middle, and multiple restricting walls may be provided.

10...lever hoist, 11, 12...frame, 12a...through hole, 12b...shaft hole, 13...casing, 14...brake cover, 14a...flange portion, 14a1...insertion hole, 15...lock cover, 15a...rising portion, 15b...opposing surface, 15b1...through hole, 20...load sheave, 20a...insertion hole, 21...load gear, 25...drive shaft (corresponding to shaft-shaped member), 26...male thread portion, 27...pinion gear, 30...reduction gear, 31...large diameter gear portion, 32...small diameter gear portion, 34...gear box, 35...female thread member, 36...female thread portion, 37 ...Switching gear, 40...Switching claw, 45...Switching knob, 50...Operating lever, 55...Cam member, 60...Idling grip, 70...Brake device, 71...Brake receiver, 71a...Flange portion, 71b...Hollow boss portion, 72a, 72b...Brake plate, 80...Ratchet wheel (corresponding to part of ratchet mechanism), 83...Ratchet teeth, 90...Claw member (corresponding to part of ratchet mechanism), 91...Claw shaft, 92...Bush, 93...Torsion spring, 93a...Coil portion, 100...Rotation lock (load drop prevention) device, 110...Stopper engaging member (corresponding to stopper engaging means) ), 111... mounting hole, 111a... inner wall surface, 112... inner protrusion portion, 113... recessed portion, 114... locking wall, 114a... corner portion, 115... pawl shaft (corresponding to part of the ratchet mechanism), 116... rib, 120... stopper support member, 120a... narrow piece portion, 120b... wide piece portion, 121... center hole, 122... bearing boss portion, 123... stopper storage portion, 123a... side wall, 123b... bottom surface, 124... insertion hole, 125... storage recess, 126... fall-out prevention recess, 127... inclined wall, 130... stopper member, 130a... bottom surface, 131... stopper projection, 132 ...Outer surface, 140...holding plate, 141...hole, 142...center hole, 143...engagement protrusion, 144...spring receiving protrusion, 145...guide groove, 145a...allowance groove, 145a1...inner wall, 145b...clearance groove, 145b1...first restriction wall, 145c...return restriction groove, 145c1...second restriction wall, 146...holding protrusion, 146a...protrusion tip, 150...biasing unit (corresponding to biasing means), 151...biasing spring, 152...one end latch pin, B1...stay bolt (corresponding to fastening member), C1...chain, R1...connecting member, SP1...space

Claims (8)

a stopper support member attached to the shaft-shaped member and rotating integrally with the shaft-shaped member;
a stopper member supported by the stopper support member in a state in which the stopper member can slide outward from an axial center side of the shaft-shaped member;
a holding plate that is provided in a disk shape and is rotatable relative to the stopper support member, and that holds the stopper member at a predetermined position on the stopper support member;
a biasing means for biasing the holding plate toward the stopper support member in a first rotation direction, which is one of the rotation directions;
a stopper engaging means for engaging with the stopper member to stop rotation of the shaft member;
Equipped with
The stopper member has a stopper protrusion protruding toward the holding plate,
the holding plate has a guide groove that engages with the stopper projection to hold the stopper member at a predetermined position in the radial direction of the stopper support member,
the guide groove has a first restriction wall with which the stopper member engages at a predetermined position in the radial direction and which is formed as an arc concentric with the shaft-shaped member, and a second restriction wall with which the stopper member engages at a position where it protrudes outward from the predetermined position in the radial direction,
The second restriction wall is provided on one side in a circumferential direction of the guide groove,
When the rotation of the shaft-shaped member is accelerated toward the first rotation direction, the stopper support member and the holding plate rotate relatively against the biasing force of the biasing means, and when the stopper projection is disengaged from the first restriction wall, the stopper member protrudes from a predetermined position to a position where it engages with the stopper engaging means, thereby stopping the rotation of the shaft-shaped member, and
a third regulating wall is provided on the other circumferential side of the guide groove, the third regulating wall being configured to engage with the stopper member at a position where the stopper member protrudes from a predetermined position in the radial direction toward an outer diameter side, thereby preventing the holding plate from rotating relatively to the stopper support member in a second rotation direction opposite to the first rotation direction,
When the stopper projection is engaged with the third restriction wall, the stopper member and the stopper locking means are located at a position where they are not locked to each other.
A rotation lock device characterized by: 2. The rotation lock device according to claim 1,
a return guide wall for returning the stopper member to a predetermined position on the axial center side is provided on the other side of the third restriction wall in the circumferential direction,
The return guide wall is inclined toward the inner diameter side from one side toward the other side in the circumferential direction.
A rotation lock device characterized by: 3. The rotation lock device according to claim 2,
The third restriction wall and the return guide wall are provided on an inner wall of the movement restriction groove portion.
A rotation lock device characterized by: A rotation lock device according to any one of claims 1 to 3,
The stopper support member is made of a soft magnetic material,
A magnet is attached to at least one of the inner diameter side of the stopper member in the radial direction and the opposing portion of the stopper support member, the magnet exerting a magnetic force in a direction in which the magnets are attracted to each other.
A rotation lock device characterized by: 5. The rotation lock device according to claim 4,
Magnets are attached to the inner diameter side of the stopper member in the radial direction and to the opposing portion of the stopper support member, the magnets exerting magnetic forces in mutually attracting directions.
A rotation lock device characterized by: A rotation lock device according to any one of claims 1 to 5,
The holding plate is provided with a protruding means protruding from a front surface or a back surface of the holding plate,
the protruding means is disposed at a position where, when the holding plate is urged in the first rotation direction by the urging means, the stopper protrusion abuts against a side surface of the stopper support member before or at the same time as the stopper protrusion abuts against an end of the guide groove on an opposite side to the first rotation direction.
A rotation lock device characterized by: A rotation lock device according to any one of claims 1 to 6,
The holding plate is provided with a spring receiving protrusion that is formed by bending a part of the holding plate and is disposed on an outer diameter side of the holding plate relative to the biasing means,
The spring receiving protrusion prevents the biasing means from falling off toward the outer diameter side due to centrifugal force generated when the holding plate rotates.
A rotation lock device characterized by: A load sheave is supported by a pair of frames and has a chain around it that lifts the load.
A drive shaft connected to the load sheave via a reduction gear;
A brake device attached to the drive shaft;
A hoisting machine comprising: an operating lever for rotating and driving the load sheave in a hoisting and lowering direction,
A rotation lock device according to any one of claims 1 to 6 is disposed on the outer periphery of the drive shaft,
the shaft-shaped member is the drive shaft,
The stopper locking means is attached to the frame.
A hoisting machine characterized by the above.

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