JPS6212150B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a safety device for a traction device, and in particular, a safety device for detecting rapid movement of a suspended object towed by a traction device in a falling direction to prevent movement of the suspended object. The present invention relates to a safety device for such a traction device with stop control.

A typical example to which the present invention is applied is a gondola that is suspended from a high place when cleaning the exterior of a high-rise building.

Some gondolas are suspended from a fixed point, such as the roof of a high-rise building, by two ropes at both ends. An appropriate winch is used as a means for moving the gondola up and down. In such a gondola, an accident in which the gondola falls due to a slip between the winch and the rope or a break in the rope can lead to personal injury and must be strictly prevented.

Therefore, the main object of the present invention is to provide a safety device for a traction device that stops and controls the movement of a suspended object such as a gondola by detecting rapid movement of the suspended object in the falling direction. That's true.

The present invention is a safety device for a traction device that is used in connection with a traction device for towing a suspended object, and that detects rapid movement of the suspended object in a falling direction and controls the movement of the suspended object to stop. , In order to solve the above-mentioned technical problem, the following configuration is adopted. That is, a linear body suspended from a predetermined fixed point, a pair of claws positioned so as to sandwich the linear body from both sides so as to be able to substantially move in parallel and approach and separate from each other; At least two gripping links constitute a parallelogram-connected link mechanism together with a pair of claws and are rotatably attached to the hanging object, and the pair of claws approach each other to form a parallelogram-connected link mechanism. a gripping device comprising a spring that is always biased to rotate the gripping link in the direction of gripping the body; Press into pieces,
a lever for rotating the gripping link against the elasticity of the spring by this pressure contact, thereby forcing the pair of claws in a direction to separate them from each other; and one at the other end of the lever. a first link whose ends are rotatably connected; one end is rotatably connected to the other end of the first link, and the other end is rotatably attached to the hanging object; a second link, and a second link for defining the end of the bending motion of the first and second links in one direction, and a state in which the first and second links are slightly deviated from a straight state. The position of the connection point with the lever is fixed by holding the lever, and in this state, the lever is brought into pressure contact with the grip link so as to rotate the grip link in a direction that separates the pair of claws from each other. a rotating body that is in frictional contact with the linear body and rotates in response to relative movement of the linear body; and a rotating body that is attached to the rotating body and rotates the rotating body in a predetermined manner. It moves in a radial direction with a centrifugal force of more than a predetermined amount exerted by more than one rotation, collides with the first or second link with rotation, and bends the first and second links in opposite directions. , and a centrifugal force sensing member that removes the force of the lever pressing against the grip link.

In this way, in this invention, each element included therein can be roughly divided into a detection mechanism for detecting an abnormal state, a gripping mechanism that grips the linear object in an abnormal state, and a gripping mechanism that grips the linear object in a normal state. The above-mentioned linear body, rotating body, and centrifugal force sensing member constitute a detection mechanism, the grip device constitutes a grip action mechanism, and the lever and the first and The second link and the bending range defining means constitute a release state maintaining mechanism. To summarize the operation, until the detection mechanism detects an abnormal state, the release state maintenance mechanism maintains the gripping mechanism in the release state to allow the passage of the linear object. I'll keep it. On the other hand, when the detection mechanism detects an abnormal state, the operation of the detection mechanism is transmitted to the release state maintenance mechanism, and the release state maintenance mechanism causes the grip action mechanism to maintain the release state. It is said that this is no longer possible. Therefore, the gripping mechanism is in a state of gripping the linear body.

What is particularly noteworthy here is that the gripping mechanism is always biased to grip the linear object, and the release state maintaining mechanism merely prohibits the gripping mechanism from gripping in normal conditions. In addition, the detection mechanism only provides a prompt to the released state maintaining mechanism to release the gripping mechanism.

More specifically, while the first and second links are maintained in a state slightly deviated from the straight state by the bending range defining means, the lever is in pressure contact with the gripping link; The pair of claws are kept separated from each other, allowing free passage of the linear body.

On the other hand, when the linear body moves abnormally rapidly and the rotational speed of the rotating body exceeds a predetermined value, and the centrifugal force sensing member moves in the radial direction, the centrifugal force sensing member moves in the first or second direction along with the rotation of the rotating body. colliding with the second link, causing the first and second links to bend in opposite directions; As a result, the lever rotates and the pressed state against the grip link is released, and the grip link acts in the direction of bringing the pair of claws closer to each other due to the action of the spring, and the linear body moves between the pair of claws. It is gripped by the claws, and as a result, the linear body becomes fixed relative to the hanging object.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view for explaining one embodiment of the present invention when it is implemented in connection with a gondola. The gondola 1 is suspended by two hanging ropes 2 at both left and right ends. This hanging rope 2 is guided through the inside of a winch 3, and the gondola 1 is moved up and down by driving this winch 3. Safety devices 4 according to an embodiment of the present invention are provided at both left and right ends of the gondola 1 and corresponding to the diagonal direction thereof. Safety device 4 includes
An auxiliary rope 5 as a linear body for backing up accidents related to the above-mentioned hanging rope 2 is passed through. When the safety device 4 is installed, for example, at the bottom of the gondola 1, as shown in FIG.
Preferably, a guide 6 for guiding the auxiliary rope 5 is provided in the upper part of the gondola 1. A weight 7 is suspended from the lower end of the auxiliary rope 5. This prevents the auxiliary rope 5 passing through the safety device 4 from always being under a certain level of tension even when the gondola 1 is lowered to a relatively low position, causing undesirable slack in the auxiliary rope 5. This is to prevent this. The configuration of the safety device 4 will be described in detail below.

FIG. 2 is a right side view of a safety device according to an embodiment of the present invention, with the housing portion on the near side in this drawing being removed to show the internal structure. FIG. 3 is a front view of the safety device of FIG. 2, with a portion of the housing on the near side in this drawing being removed to show the internal structure. Fourth
The figure corresponds to FIG. 3 and shows the state in which this safety device is activated.

The safety device 4 includes a case 8, which is divided into two rooms 10 and 11 by a partition 9. The auxiliary rope 5 is passed through the first chamber 10, and a mechanism for detecting the relative movement speed of the auxiliary rope 5 and a device for grasping or releasing the auxiliary rope 5 are mainly arranged here. Ru.
In the second chamber 11, a mechanism for activating the gripping action of the gripping device depending on the relative movement speed of the auxiliary rope 5 is mainly arranged. In addition, the third
In the figures and FIG. 4, illustration of the partition 9 is omitted, and the components arranged in both the first room 10 and the second room 11 are shown overlapping each other. When this safety device 4 is attached to the aforementioned gondola 1 etc., the auxiliary rope 5 of the case 8
The wall surface 12 closest to is the mounting surface. this is,
This is to reduce the distance between the auxiliary rope 5 and the mounting surface as much as possible, and to reduce the burden on the case 8 due to the load generated between the auxiliary rope 5 and the wall surface 12 as much as possible.

The auxiliary rope 5 is passed through the first chamber 10 within the case 8, as briefly mentioned above. The auxiliary rope 5 is guided through bushes 13 provided through the upper and lower walls of the case 8, respectively. In connection with this auxiliary rope 5 a gripping device 14 is arranged. The gripping device 14 has the following configuration, for example. That is,
The right claw 15 and the left claw 16 are arranged to sandwich the auxiliary rope 5. When the right claw 15 and left claw 16 are separated from each other, the auxiliary rope 5
When the auxiliary ropes 5 come close to each other, the auxiliary ropes 5
A grasping state is realized and relative movement of the auxiliary rope 5 is prohibited. The right claw 15 and the left claw 16 have two semicircular shaft protrusions 17 on both sides of each.
18 are provided. In FIGS. 3 and 4, only the semicircular protrusions 17 and 18 formed on one side of each pawl 15 and 16 are shown, but semicircular protrusions of similar shape are shown on each side. It is also formed on the other side of the claws 15 and 16. 1 facing each other
The pair of semicircular shaft protrusions 17 and 18 are connected to the grip link 19
It is received in an eccentric semicircular hole 20 formed in. The grip link 19 is rotatably held by a pin 21 fixedly provided to the case 8. In this way, the right pawl 15, the left pawl 16 and the two gripping links 19 are attached to the case 8 in a parallelogram connection. A spring 22 is disposed around each pin 21, and both ends of the spring 22 abut against pins 23 fixed to each grip link 19, so that each grip link 19 moves clockwise around the pin 21. is urged to rotate. This clockwise rotation results in a posture as shown in FIG.
The pair of semicircular shaft protrusions 17 and 18 are brought closer to each other, and the right claw 15 and left claw 16 are moved substantially in parallel and brought closer to each other. A lever 24 is provided on one grip link 19 so that one end thereof contacts. The lever 24 is rotatably supported by a shaft 25 fixedly provided to the case 8 . This movement of the other end of the lever 24 is transmitted to a mechanism disposed in the second chamber 11, which will be described later.

A pulley 26 is rotatably provided below the gripping device 14. The pulley 26 is connected to the auxiliary rope 5
It rotates by receiving the relative movement of the two through frictional contact. The auxiliary rope 5 is attached to the pulley 26.
Although a U-groove is formed on its circumferential surface for receiving the auxiliary rope 5, a V-groove may be formed in order to increase the apparent coefficient of friction with the auxiliary rope 5. A hold-down pulley 27 may be provided to ensure that the auxiliary rope 5 is in frictional contact with the pulley 26. Presser pulley 27
The shaft 28 is mounted on a bracket 30 which is rotatably supported with respect to the case 8 by a pin 29. This bracket 30 is connected to a tension spring 31 connected to a suitable fixing point of the case 8.
It is urged to rotate in the counterclockwise direction as shown in FIG. 3 about the pin 29. Therefore, the presser pulley 27 is urged to move in the direction of the pulley 26, and the auxiliary rope 5 is reliably brought into frictional contact with the pulley 26 between the pulley 26 and the presser pulley 27. Various other modifications may be possible as a way of providing the spring for biasing the presser pulley 27 to move in the direction of the pulley 26.

In the second room 11, the other end 24b of the lever 24 described above is arranged. One end of a first link 33 is rotatably connected to the other end 24b via a pin 32, and one end of a second link 35 is connected to the other end of the first link 33 via a pin 34. The ends are rotatably connected. A shaft 36 is fixedly attached to the other end of the second link 35,
The shaft 36 is rotatably held relative to the case 8. The shaft 36 extends to the outside of the case 8, and a handle 37 is provided here. Since the handle 37 is provided to rotate integrally with the shaft 36 and therefore also rotates integrally with the second link 35, the handle 37 rotates the second link 35 from outside the case 8. It becomes a means of operation for The first link 33 is composed of a connecting rod 38 having a double screw thread in its middle portion. Therefore, by rotating this connecting rod 38 about its axis, the entire length of the first link 33, that is, the distance between the pins 32 and 34 can be adjusted.

When looking at the first link 33 and the second link 35, they can be bent around the pin 34. This bending is possible in any direction, but for bending in one direction, a bending range defining means is provided to define the end of this bending motion. As an example, a stopper 39 is provided near the pin 34 so as to come into contact with, for example, the first link 33. stoppa 39
is preferably constituted by a bolt screwed into a bracket 40 fixedly provided on the partition 9, for example. According to this, the position of the stopper 39 can be easily adjusted by turning this bolt. After completing the desired adjustment, the stopper 39 is fixed by tightening the nut 41. The position of the stopper 39 is preferably selected such that the first link 33 and the second link 35 are slightly bent, but no further bending occurs. This is to increase the sensitivity of this safety device 4, as will become clear from the description later. In FIG. 3, the first link 33 and the second link 35 are illustrated as if they are aligned in a straight line, but in reality, the pin 34 is displaced to the left in this drawing. It is slightly bent in the direction. Note that instead of the stopper 39, the first link 33 and the second link 35
As the bending range defining means in one direction, a protrusion or the like having a shape that directly engages with the first link 33 and the second link 35 itself may be provided.

The shaft 42 of the pulley 26 described above is provided to extend into the second chamber 11, and this shaft 42
2 is rotatably provided with respect to the case 8,
It is provided to rotate integrally with the pulley 26. In the second chamber 11, a disk 43 is also fixed to the shaft 42. Therefore, the disc 43, the shaft 42, and the pulley 26 constitute one rotating body that rotates integrally. For example, two centrifugal force sensing members 45 are rotatably provided on the disc 43 via pins 44 . The centrifugal force sensing member 45 is rotated by the centrifugal force when the disk 43 rotates, and its tip portion moves in the radial direction. A tension spring 46 is connected between the two centrifugal force sensing members 45, and the spring force causes the centrifugal force sensing member 45 to move in the radial direction only when the disc 43 rotates at a predetermined number of rotations or more. configured to move to. This tension spring 46
By appropriately selecting , the number of rotations of the disc 43 when the centrifugal force sensing member 45 moves in the radial direction can be arbitrarily set. The tension spring 46 is
Although it is provided so that both centrifugal force sensing members 45 are connected, it may be provided individually for each centrifugal force sensing member. Moreover, such a tension spring 4
6 may be replaced by, for example, a torsion spring that urges the centrifugal force sensing member 45 to rotate clockwise in FIG. 3 around the pin 44. Furthermore, the number of such centrifugal force sensing members 45 may be just one, or the number may be further increased. The rotation, that is, the movement in the radial direction, of the centrifugal force sensing member 45 is restricted within a certain range. Therefore, for example, as shown by dotted lines in FIGS. 3 and 4, a pin 47 is provided protruding from the disk 43 side, and this pin 47 is received on the back surface of the centrifugal force sensing member 45. A hole 48 is provided. The size of this hole 48 is made larger than the diameter of the pin 47, so that the centrifugal force sensing member 45 can move by the margin of the hole 48 with respect to the pin 47. Instead of such a combination of pins 47 and holes 48, two pins are set up on the disk 43, and the movement range of the centrifugal force sensing member 45 is defined within the range in which the centrifugal force sensing member 45 comes into contact with the pins. You may. When the centrifugal force sensing member 45 moves in the radial direction due to centrifugal force, its tip reaches a state where it can collide with a portion of the first link 33 near the pin 34. In this embodiment, the centrifugal force sensing member 45 is provided so as to be rotatable about the pin 44, but may be provided so as to be slidable in the radial direction. Namely. The disk 43 is provided with a groove or hole extending in the radial direction, and the centrifugal force sensing member is slidably disposed in the groove or hole so that the centrifugal force sensing member is slid in the radial direction by the centrifugal force. may be configured.

Next, the operating method and operation of the above-described embodiment will be explained.

First, operations such as adjustment of the safety device 4 in the preparation stage will be explained. Auxiliary rope 5
is inserted into this safety device 4. This is achieved by inserting the auxiliary rope 5 from the upper bush 13. In this case, since the distance between the pair of claws 15 and 16 of the gripping device 14 and the distance between the pulley 26 and the presser pulley 27 are aligned between the upper and lower bushes 13, the auxiliary rope 5 inserted from above can be easily taken out from the lower bushing 13. It should be noted that at this stage of inserting the auxiliary rope 5, the gripping device 14 must be in the released state. This is accomplished by turning the handle 37 counterclockwise in FIG. 3, flexing the first and second links 33, 35 until they abut the stop 39. The first and second links 33, 35 are connected to this stopper 39.
Stable when in contact with. At this time, lever 2
4 presses against the grip link 19 and rotates the grip link 19 counterclockwise in FIG.
6 are in an open state, and the gripping device 14 is in a released state.

Appropriate adjustment operations may be performed during this preparation stage. For example, by turning the double-threaded connecting rod 38 included in the first link 33,
The length of the first link 33 is adjusted. By this adjustment, the distance between the right pawl 15 and the left pawl 16 in the released state of the gripping device 14 shown in FIG. 3 is adjusted. For example, if the length of the first link 33 is made longer, the gripping link 19 will be rotated more counterclockwise in the state shown in FIG. is formed. Such adjustments can be made using the auxiliary rope 5.
It has the function of adapting to the thickness of wire rope used as a wire rope. Further, the position of the stopper 39 may be adjusted. This adjusts the bent state of the first link 33 and the second link 35 in the initial state shown in FIG. 3. The first link 33 and the second link 35 are bent in opposite directions as shown in FIG. 4 in order to bring the gripping device 14 into the gripping state. In order for the bending to be realized, the first
It is desirable that the link 33 and the second link 35 are aligned in a state closer to a straight line. on the other hand,
If the first link 33 and the second link 35 are too close to a straight line state, the first link 33 and the second link 35 may become disconnected due to external vibrations even if no abnormal condition has occurred. This is not preferable since it will be bent in the opposite direction. Therefore, the position of the stopper 39 must be determined taking such conditions into consideration.

Next, the operation of the safety device 4 will be explained using the gondola 1 shown in FIG. 1 as an example. When the gondola 1 is moving up and down by the drive of the winch 3, the auxiliary rope 5 freely passes through the safety device 4. At this time, the auxiliary rope 5 is attached to the pulley 26.
are in contact with each other, this relative movement of the auxiliary rope 5 causes the pulley 26 to rotate. Therefore, the disk 43 is also rotating integrally with this. However, under normal conditions,
The speed of the relative movement of the auxiliary rope 5 is not so high, and therefore the rotational speed of the pulley 26 and the disc 43 is not so high either, and the centrifugal force sensing member 45 resists the spring force of the tension spring 46 in the radial direction. Not even close to moving. Therefore, the first
link 33, second link 35 and lever 2
4 remains in place, and the gripping device 14 remains in the released state.

Next, it is assumed that the suspension rope 2 is cut or a slip occurs between the suspension rope 2 and the winch 3, and the gondola 1 rapidly falls. At this time, the auxiliary rope 5 performs a rapid relative movement with respect to the safety device 4. The direction of the movement is such that the auxiliary rope 5 moves upward with respect to the safety device 4 when viewed relatively. Therefore, pulley 26 and disk 43 rapidly rotate clockwise in FIG. 3. In response to this, a centrifugal force of a predetermined value or higher acts on the centrifugal force sensing member 45, and as shown in FIG. In this state, since the disk 43 continues to rotate, one centrifugal force sensing member 45 collides with the vicinity of the pin 34 connecting the first and second links 33 and 35. This collision of the centrifugal force sensing member 45 causes the first and second links 33, 35 to
is in a bent state as shown in FIG. Now, considering the force that acts during the transition from the state shown in FIG. 3 to the state shown in FIG. 4, first, the centrifugal force sensing member 45
This first and second link 3 after colliding with 5
Until the so-called consideration point at the bends 3 and 35 is exceeded, the operation proceeds by applying force due to the relative movement of the auxiliary rope 5 to the centrifugal force sensing member 45 via the pulley 26 and the disk 43. From this point of view, it is necessary that the auxiliary rope 5 is in reliable contact with the pulley 26, and for this reason the presser pulley 26 works advantageously. As a means for bringing the auxiliary rope 5 into reliable contact with the pulley 26, a method may be adopted in which the auxiliary rope 5 is wound around the pulley 26 at least once without using the presser pulley 27. Next, after going beyond the above considerations, the first and second links 3
3 and 35 are in a state where they can be bent freely, so the lever 24 can freely change its posture, and the grip link 19 is held by the action of the spring 22.
is quickly rotated clockwise in FIG. At this time, the distance between the right claw 15 and the left claw 16 is narrowed, and the auxiliary rope 5 is connected to these claws 15 and 16.
6, the relative movement of the auxiliary rope 5 also causes the gripping link 19 to rotate in this clockwise direction via the pawls 15, 16. In this way, the auxiliary rope 5 is grabbed by the gripping device 14 and the gondola 1 is immediately prevented from falling.

In addition, when a plurality of safety devices 4 are attached to the gondola 1 as shown in FIG. 1, when one safety device 4 is activated, a sudden impact will be applied to the gondola 1 itself. This impact will also activate other safety devices 4. That is, as described above, the first and second links 3
3 and 35 are maintained in that position by the stopper 39 just beyond the point in their bending motion, but if such an impact is applied,
This is because the first and second links 33 and 35 will easily be operated beyond the point of consideration.

In order to release the above-mentioned abnormal condition and restore the safety device 4, the handle 37 may be rotated counterclockwise in FIG. 4. Accordingly,
The state shown in FIG. 3 is obtained.

Although the above-described embodiment has been described in relation to the safety device 4 of the gondola 1, the safety device of the present invention is not limited to gondolas, and can be advantageously applied to any towing device that tows an appropriate hanging object. Can be applied.

As described above, according to the present invention, the gripping device as the gripping action mechanism always acts to grip the linear object, and the lever included in the release state maintaining mechanism is connected to the first and second links. Only while the gripping device is maintained in a state slightly deviated from the straight state by the bending range defining means, the gripping link included in the gripping device is pressed against the gripping link to keep the gripping device in the released state. In the event of an abnormality, the centrifugal force sensing member included in the detection mechanism
colliding with the first and second links, the bending states of the first and second links are reversed, and these links are bent relatively significantly. Correspondingly, the lever is no longer pressed against the gripping link and the gripping device assumes the gripping condition on its own. That is, in this invention, in the transmission of motion from the detection mechanism to the release state maintenance mechanism to the grip action mechanism, the final grip action mechanism transmits the power applied from the detection mechanism via the release state maintenance mechanism. It is not transmitted and operated by this power.
The grasping mechanism has the ability to operate by itself, and this operating ability is only disabled by the release state maintenance mechanism in normal conditions, and when the detection mechanism detects an abnormality, the Only a so-called "signal" is given from the detection mechanism, and this "signal" releases the release state maintenance mechanism from disabling the grasping mechanism, and as a result,
The gripping mechanism performs the gripping action in its own capacity. Therefore, it is possible to obtain a highly safe safety device for a traction device that can reliably and quickly respond to an abnormal operation of a suspended object and prevent the suspended object from falling. In addition, the detection mechanism that activates this safety device uses the power obtained from the relative movement between the suspended object and the linear object, so
There is no need to take in power from the outside, and the cause of failure due to such external power is eliminated, and in this sense, a safer safety device can be obtained. In addition, the claws that grip the linear body in abnormal situations,
Since the linear body is moved substantially in parallel so as to sandwich the linear body from both sides, the linear body can be used repeatedly without damaging the linear body. Furthermore, this invention utilizes the centrifugal force acting on the centrifugal force sensing member, and since this centrifugal force is proportional to the rotational speed of the rotating body, the centrifugal force sensing member operates only depending on the rotational speed of the rotating body. Therefore, no matter in what position this safety device is installed or brought into
This can be said to be more preferable in terms of improving safety because a constant response condition can be obtained. Furthermore, since the safety device of the present invention can operate independently regardless of the type of traction device such as a winch used in connection with it, no design changes are required to the traction device used in the past. There is no need for this, and a towing device with increased safety can be obtained by simply installing the safety device of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a perspective view for explaining one embodiment of the present invention when it is implemented in connection with a gondola. FIG. 2 is a right side view of one embodiment of the present invention, with the housing portion on the near side in this drawing being removed to show the internal structure. Third
The drawing is a front view of the safety device shown in FIG. 2, with the housing portion on the near side in this drawing being partially removed to show the internal structure. Figure 4 is the third
This figure shows the state in which this safety device is activated. In the figure, 1 is a gondola as a hanging object,
3 is a winch as a traction device, 4 is a safety device,
5 is an auxiliary rope as a linear body, 8 is a case, 1
4 is a gripping device, 24 is a lever, 25 is a shaft, 26 is a pulley that constitutes a part of the rotating body, 32
is the pin, 33 is the first link, 34 is the pin, 35
36 is a shaft, 39 is a stopper as a bending range defining means, 42 is a shaft forming a part of the rotating body, 43 is a disc forming a part of the rotating body, 44 is a pin, 45 is a centrifugal force sensing member, and 46 is a tension spring.

Claims (1)

[Claims] 1. A safety device for a traction device used in connection with a traction device for towing a suspended object, which detects rapid movement of the suspended object in the falling direction and controls the movement of the suspended object to stop. A linear body suspended from a predetermined fixed point, and a pair of claws positioned to sandwich the linear body from both sides and movable substantially in parallel to approach and separate from each other. , at least two gripping links forming a parallelogram-connected link mechanism together with the pair of claws and rotatably attached to the hanging object; and the pair of claws approaching each other; a gripping device comprising a spring that is always biased to rotate the gripping link in the direction of gripping the linear object; and a gripping device that is rotatably attached to the suspended object and has one end connected to the gripping link. Press it against one of the
a lever for rotating the gripping link against the elasticity of the spring by this pressure contact, thereby forcing the pair of claws in a direction to separate them from each other; and one at the other end of the lever. a first link whose ends are rotatably connected; one end is rotatably connected to the other end of the first link, and the other end is rotatably attached to the hanging object; a second link, and a second link for defining the end of the bending motion of the first and second links in one direction, and a state in which the first and second links are slightly deviated from a straight state. The position of the connection point with the lever is fixed by holding the lever, and in this state, the lever is brought into pressure contact with the grip link so as to rotate the grip link in a direction that separates the pair of claws from each other. a rotating body that is in frictional contact with the linear body and rotates in response to relative movement of the linear body; and a rotating body that is attached to the rotating body and rotates the rotating body in a predetermined manner. It moves in a radial direction with a centrifugal force of more than a predetermined amount exerted by more than one rotation, collides with the first or second link with rotation, and bends the first and second links in opposite directions. , a centrifugal force sensing member that eliminates the force of the lever pressing against the grip link.