JP7611044B2 - crane - Google Patents

Description

The present invention relates to a crane.

Patent document 1 shows a jib mooring device that can hold and release the jib using an actuator, and can also hold and release the jib manually even if the actuator becomes inoperable.

Patent No. 6756239

However, with the above-mentioned jib mooring device, if the actuator becomes stuck and inoperable, it becomes impossible to manually switch between holding and releasing the jib.

The present invention aims to reduce the occurrence of situations in which it is impossible to switch between holding and releasing the jib.

The crane according to the present invention comprises:
A crane comprising a boom, a jib attached to the boom so as to be able to be raised and lowered, and a holding mechanism for holding the jib in a folded state relative to the boom,
The holding mechanism includes:
A locking member movable between a locking position for holding the jib and an unlocking position for releasing the holding of the jib;
a first operating member and a second operating member that move the locking member to the lock position and the unlock position by their own drive or by receiving an external force;
having
the second operating member is configured to be able to move the locking member to the unlocking position regardless of a state of the first operating member when the first operating member cannot move the locking member to the unlocking position ,
Furthermore,
A first support member that supports the first operating member,
The second operating member is configured to disengage the first operating member from the first support member when the locking member is moved .

The present invention reduces the occurrence of situations in which it is impossible to switch between holding and releasing the jib.

FIG. 1 is a side view showing a crane according to an embodiment of the present invention. 1A is a plan view, FIG. 1B is a front view, and FIG. 1C is a side view showing a holding mechanism of the embodiment. FIG. 13 is a rear perspective view showing a first support member of the holding mechanism; 5A and 5B are diagrams illustrating a locked position and an unlocked position of the hook member. 1A to 1C are diagrams illustrating the operation of holding and releasing the jib by operating the first operating member, and FIG. 1C shows each step of the operation. 1A to 1C are diagrams illustrating the operation of the holding mechanism when the first operating member fails when the operating part is fully extended, where (a) shows the process of releasing the first operating member, (b) shows the process of holding the jib, and (c) shows the process of releasing the hold on the jib. 10A to 10C are diagrams illustrating the operation of the holding mechanism when the first operating member fails while the actuating part is moderately pushed out, where (a) shows the process of releasing the first operating member, (b) shows the process of holding the jib, and (c) shows the process of releasing the hold on the jib. 1A to 1C are diagrams illustrating the operation of the holding mechanism when the first operating member fails when the operating part is fully retracted, where (a) shows the process of releasing the first operating member, (b) shows the process of holding the jib, and (c) shows the process of releasing the hold on the jib. 1A is a side view of a holding mechanism showing a lock detection device, in which FIG. 1A shows a state when the jib is held, and FIG. 1B shows a state when the holding of the jib is released.

The following describes an embodiment of the present invention in detail with reference to the drawings.

Figure 1 is a side view showing a crane according to an embodiment of the present invention. In Figure 1, the folded state of the jib 14 is shown by a solid line, and the raised state of the jib 14 is shown by a two-dot chain line.

The crane 1 of this embodiment includes a lower structure 11, an upper rotating body 12 that rotates relative to the lower structure 11, a boom 13 connected to the upper rotating body 12 so that it can be raised and lowered, a jib 14 connected to the boom 13 so that it can be raised and lowered, a hook 15 suspended from the jib via a wire rope L, a holding mechanism 20 that can hold the jib 14 in a folded state relative to the boom 13, and a cab 18 that has a driving operation section that receives driving operations from an operator.

The crane 1 is, for example, a tower crane. The folded state of the jib 14 held by the holding mechanism 20 is, for example, a state in which the boom 13 is raised and the jib 14 is close to the boom 13.

The lower structure 11 may be a traveling body such as a crawler, or may be a fixed structure. The upper rotating body 12 is provided with a plurality of winches U that wind up or pay out wire ropes to raise and lower the boom 13, the jib 14, and the hook 15. The operator's cab 18 may be provided with an operating means (such as an operating button) for driving the first operating member (electric actuator) 23 of the holding mechanism 20.

Figure 2 shows a plan view (a), a front view (b), and a side view (c) of the holding mechanism of the embodiment. Figure 3 is a rear perspective view showing the first support member of the holding mechanism. Figure 4 is a diagram explaining the locked position (a) and the unlocked position (b) of the hook member. In Figure 4 and Figures 5 to 7 shown below, the bar (held portion) 31 is shown in cross section midway in the longitudinal direction, and the configuration related to the biasing member 25 is omitted.

The holding mechanism 20 is a mechanism that can hold and release the jib 14 when the jib 14 is folded relative to the boom 13, with its main part attached to the boom 13. The holding mechanism 20 includes a base member 21 connected to the main member or auxiliary member of the boom 13, a hook member 22 supported rotatably on the base member 21, a rotation shaft 22x connecting the left and right hook members 22, a first operating member 23 that can move the hook member 22 by driving itself, a second operating member 24 that can move the hook member 22 by receiving a force from the outside, a biasing member (e.g., a coil spring) 25 that biases the hook member 22 in one of the rotation directions, a first support member 26 that detachably supports one end of the first operating member 23, a stay 27 that supports each member, and a bar 31 that is connected to the main member or auxiliary member of the jib 14. The hook member 22 corresponds to an example of a locking member according to the present invention.

The stay 27 includes a support portion 27a that rotatably supports one end of the first operating member 23, a connecting portion 27b that connects the second operating member 24, a support portion 27c that supports the biasing member 25, and a member support portion 27d that supports the first operating member 23 when the first operating member 23 is detached from the first support member 26. The stay 27 is attached to the hook member 22. The member support portion 27d corresponds to an example of a second support member according to the present invention.

The hook member 22 has a hook portion 22h that can hook onto the bar 31 and restrain the bar 31, a cam portion 22c that is located closer to the pivot axis than the hook portion 22h and against which the bar 31 can abut, and an inclined portion 22a that is located on the edge of the pivot side (see FIG. 4(a)).

As shown in FIG. 4(a), the hook member 22 can move (rotate) between a lock position P1 where the bar 31 can be held and an unlock position P2 where the bar 31 is released from the hold, as shown in FIG. 4(b). Holding the bar 31 means holding the jib 14 to which the bar 31 is connected. Releasing the hold of the bar 31 means releasing the hold of the jib 14 to which the bar 31 is connected. The hook member 22 rotates in a direction along a plane intersecting the longitudinal direction of the bar 31. At the lock position P1, the hook portion 22h is located on the movement path of the bar 31 (the movement path associated with the rotation of the jib 14), and when the bar 31 is located within the hook portion 22h, even if the bar 31 moves in a direction away from the hook member 22, the bar 31 is hooked on the bar 31 so that it does not come off the hook member 22. At the unlock position P2, the hook portion 22h comes off the movement path of the bar 31 (the movement path associated with the rotation of the jib 14). Hereinafter, the rotation direction of the hook member 22 from the unlocked position P2 to the locked position P1 will be referred to as the "lock direction," and the direction from the locked position P1 to the unlocked position P2 will be referred to as the "release direction."

When the hook member 22 is in the unlocked position P2, the bar 31 moves as the jib 14 is lowered, and the bar 31 comes into contact with the cam portion 22c, exerting a force on the hook member 22 in the locking direction.

When the hook member 22 is in the lock position P1, the inclined portion 22a abuts against the bar 31 due to the movement of the bar 31 caused by the collapse of the jib 14, exerting a force on the hook member 22 in the release direction.

The biasing member 25 generates a biasing force between the base member 21 and the hook member 22, and applies a force in the locking direction to the hook member 22. When no external force is applied to the hook member 22, the biasing force of the biasing member 25 moves the hook member 22 to the locking position P1. A part of the biasing member 25 is connected to the base member 21, and another part of the biasing member 25 is connected to the hook member 22 via the stay 27.

The first operating member 23 is an electric actuator that has a base and an operating part, and can move the operating part relative to the base (e.g., push and retract). The first operating member 23 may be, for example, an electric actuator that converts the rotational drive of an electric motor into linear motion of the operating part. With this configuration, it is possible to generate a large electrical retraction or push-out force, and also obtain the characteristic that the operating part does not move easily in response to external forces.

One of the base and the operating part of the first operating member 23 is supported by the first support member 26, and the other is supported by the hook member 22 via the stay 27. The first operating member 23 is supported rotatably relative to the stay 27, and is also supported rotatably relative to the first support member 26. Therefore, a force is generated in the first operating member 23 that attracts the operating part, and a force in the release direction can be applied to the hook member 22.

The movable range W1 of the hook member 22 caused by the operation (drive) of the first operating member 23 includes a locked position P1 and an unlocked position P2. In FIG. 4(b), the movable range W1 of the hook member 22 is represented by the range of variation in the angle of the central axis of the second operating member 24.

As shown in FIG. 3, the first support member 26 has a groove frame 26a with at least one end open, and supports a part of the first operating member 23 by hooking the protruding portion 23a of the first operating member 23 on the groove frame 26a. When the protruding portion 23a of the first operating member 23 is pulled toward the stay 27, the first support member 26 supports the first operating member 23. On the other hand, when there is no pulling force and the stay 27 and the first support member 26 approach each other, the protruding portion 23a of the first operating member 23 comes out of the groove frame 26a, and the first operating member 23 can be removed from the first support member 26.

The second operating member 24 is an arm member connected to the hook member 22 via a stay 27, and an operating rope 24a is connected to it. The arm member is a member that connects two points, and may be, for example, a long member, a rod member, a block-shaped member, a member that extends in a straight line, a member that extends in a curved path, and the like. By manually pulling the operating rope 24a, a force in the release direction can be applied from the second operating member 24 to the hook member 22. In addition, the operating rope 24a may be, for example, a cable (not shown) for supplying power or a signal to drive the first operating member 23. Alternatively, the operating rope 24a may be a cable (not shown) for supplying power or a signal to the lock detection device 40 (see FIG. 9). These cables are connected to the main body of the crane 1 and the first operating member 23, or to the main body of the crane 1 and the lock detection device 40, and transmit power or a signal. Therefore, a part of the cable can be connected to the second operating member 24. Even with this configuration, by manually pulling the cable, a force can be applied to the second operating member 24 in a direction that releases the hook member 22. In this case, the number of parts in the holding mechanism 20 can be reduced, and the number of assembly steps can also be reduced.

The movable range W2 (see also FIG. 8(a)) of the hook member 22 caused by the operation (rotation operation) of the second operating member 24 includes the locked position P1 and the unlocked position P2. The movable range W2 is greater than the movable range W1 of the hook member caused by the operation of the first operating member 23. In FIG. 4(b) and FIG. 8(a), the movable range W2 of the hook member 22 is represented by the range of variation in the angle of the central axis of the second operating member 24.

Figure 9 is a side view of the holding mechanism showing the lock detection device, where (a) shows the state when the jib is held, and (b) shows the state when the jib is released from the hold.

A lock detection device 40 is attached to the left hook member 22. The left hook member 22 is disposed on the opposite side to the right hook member 22 on which the first operating member 23 is disposed. The lock detection device 40 detects that the hook member 22 has reached the locked position P1. The lock detection device 40 includes a limit switch 41 that detects that the hook member 22 has reached the locked position P1 and is holding the bar 31, a detection lever 42 that can activate the switch of the limit switch 41, and a detection lever holding member (spring) 43 that holds the detection lever 42 so that it can come into contact with the bar 31.

The detection lever 42 is supported rotatably relative to the hook member 22. In the unlocked position P2, the detection lever 42 is biased by the detection lever holding member 43 so as not to come into contact with the switch portion 41a of the limit switch 41. When the hook member 22 moves toward the locked position P1, the detection lever 42 comes into contact with the bar 31, and rotates the detection lever 42 toward the limit switch 41. When the hook member 22 moves to the locked position P1, the detection lever 42 presses the switch portion 41a of the limit switch 41, and the limit switch 41 outputs an ON signal. This ON signal makes it possible to determine that the bar 31 is held. A display (not shown) in the cab 18 displays that the bar 31 is locked (the jib 14 is held) based on the ON signal from the limit switch 41.

<Operation of holding and releasing the jib by the first operating member>
5A to 5C are diagrams for explaining the operation of holding and releasing the jib by operating the first operating member, and are diagrams showing each step of the operation. Hereinafter, among the rotation directions of the jib 14 and the bar 31, the direction in which the jib 14 approaches the boom 13 is referred to as the "approaching direction", and the direction in which the jib 14 moves away from the boom 13 is referred to as the "moving away direction".

As shown in FIG. 5(a), when the hook member 22 is in the lock position P1 and the bar 31 is located within the hook portion 22h, the bar 31 and the jib 14 are kept in a restrained state unless an unlocking operation is performed. In other words, even if the jib 14 and the bar 31 try to move away from each other, the hook portion 22h restrains the bar 31, and the rotation of the jib 14 is also restrained.

When the first operating member 23 (electric actuator) is driven and a force is generated that attracts the stay 27 to the first support member 26, the hook member 22 rotates in the release direction as shown in FIG. 5(b). Then, when the drive amount (attraction drive amount) of the first operating member 23 is maximum, as shown in FIG. 5(c), the hook portion 22h is disengaged from the movement path of the bar 31 (the movement path of the bar 31 accompanying the raising and lowering of the jib 14), and the lock of the jib 14 is released. At this time, a force is applied to raise the jib 14, so that the jib 14 can be rotated in the separation direction. The movable range W1 corresponds to the range from the angle of the hook member 22 when the drive amount of the first operating member 23 is zero (maximum extended state) to the angle of the hook member 22 when the drive amount of the first operating member 23 is maximum (maximum retracted state).

When holding the jib 14 from a released state, first, the first operating member 23 is driven as shown in FIG. 5(c). Then, the jib 14 is folded to move the bar 31 to a position where it can be stored within the hook portion 22h. After that, the actuating portion of the first operating member 23 is pushed out as shown in FIG. 5(b) and FIG. 5(a), so that the bar 31 is restrained within the hook portion 22h, and the jib 14 can be held in the folded state.

When the jib 14 is folded, the bar 31 moves further in the approaching direction and abuts against the cam portion 22c of the hook member 22. This abutment applies a force in the locking direction to the hook member 22, allowing the operating portion of the first operating member 23 to be retracted and the hook member 22 to be rotated smoothly in the locking direction.

In each state of Figures 5(a) to 5(c), a force in the locking direction is applied to the hook member 22 by the biasing member 25 (see Figure 2(c)), and a force that pulls the first operating member 23 against the first support member 26 is applied, so that the protruding portion 23a of the first operating member 23 does not come out of the groove frame 26a of the first support member 26 (see Figure 3).

<Example of a Failure of the First Operation Member>
If the first operating member 23 (electric actuator) fails, the state of the first operating member 23 differs depending on the timing of the failure. For example, if the failure occurs at the stage shown in Fig. 5(a), the first operating member 23 freezes with the operating part fully extended. If the failure occurs at the stage shown in Fig. 5(b), the first operating member 23 freezes with the operating part moderately extended. If the failure occurs at the stage shown in Fig. 5(c), the first operating member 23 freezes with the operating part fully retracted.

On the other hand, according to the holding mechanism 20 of this embodiment, as will be described below, regardless of the stage at which the first operating member 23 fails, the jib 14 can be held and released by operating the second operating member 24.

<Operation 1 of holding and releasing the jib by the second operating member>
Figure 6 is a diagram explaining the operation of the holding mechanism when the first operating member fails when the operating part is fully extended, where (a) shows the process of releasing the first operating member, (b) shows the process of holding the jib, and (c) shows the process of releasing the hold on the jib.

When the first operating member 23 breaks down with the operating part pushed out to the maximum extent, as shown in FIG. 6(a), the operating rope 24a is pulled manually or the like, and a force is transmitted through the second operating member 24, causing the hook member 22 to rotate in the release direction. Then, since the operating part is fixed in the first operating member 23, the pulling force from the first operating member 23 to the first support member 26 disappears, and the first operating member 23 comes off the first support member 26 as shown in FIG. 6(a). That is, the protruding part 23a of the first operating member 23 moves along the groove frame 26a of the first support member 26 and comes off one end side of the groove frame 26a. The first operating member 23 released from the first operating member 23 rotates around the support part 27a according to gravity and comes into contact with the member support part 27d of the stay 27 and stops. That is, the member support part 27d supports the first operating member 23 on one side. Because the member support portion 27d is fixed to the hook member 22, the relative angle between the hook member 22 and the first operating member 23 supported by the member support portion 27d does not change even if the hook member 22 rotates. Therefore, regardless of the rotation position of the hook member 22, the member support portion 27d can continuously support the first operating member 23 at an angle that does not interfere with other members (such as the first support member 26).

When the failed first operating member 23 is detached from the first support member 26, the jib 14 can be held and released by operating the second operating member 24 without being affected by the first operating member 23.

For example, as shown in FIG. 6(b), when pulling on the operating rope 24a is stopped, the biasing force of the biasing member 25 can rotate the hook member 22 to the lock position P1. At this time, the bar 31 is positioned so that it can be accommodated within the hook portion 22h, so that the bar 31 is restrained within the hook portion 22h and the jib 14 can be held in the folded state.

When the first operating member 23 is broken and the jib 14 is to be kept in the folded state, the jib 14 may be rotated and the bar 31 moved in the approaching direction without pulling the operating rope 24a. When the bar 31 comes into contact with the inclined portion 22a of the hook member 22 as a result of this movement, the hook member 22 rotates in the release direction and the bar 31 can be pushed into the hook portion 22h.

When the jib 14 is released from its hold, as shown in FIG. 6(c), the operating rope 24a is pulled strongly, causing the hook member 22 to rotate in the release direction via the second operating member 24. Then, the hook member 22 rotates to the unlocking position P2, and the hook portion 22h moves out of the movement path of the bar 31, releasing the restraint of the bar 31 and releasing the hold of the jib 14.

The member support portion 27d supports the first operating member 23 in a position where the first operating member 23 will not return to a state where it is supported by the first support member 26, regardless of how the operating rope 24a is pulled or retracted.

<Operation 2 of holding and releasing the jib by the second operating member>
Figure 7 is a diagram explaining the operation of the holding mechanism when the first operating member fails when the operating part is moderately pushed out, where (a) shows the process of releasing the first operating member, (b) shows the process of holding the jib, and (c) shows the process of releasing the hold on the jib.

If the first operating member 23 fails with the operating part pushed out moderately, as shown in FIG. 7(a), the operating rope 24a is pulled manually or otherwise, transmitting force via the second operating member 24 and rotating the hook member 22 in the release direction. Then, since the operating part is fixed in the first operating member 23, the pulling force from the first operating member 23 to the first support member 26 disappears, and the first operating member 23 comes off the first support member 26 as shown in FIG. 7(a).

In the example of FIG. 7(a), the actuating portion of the first operating member 23 is retracted to a moderate extent, so compared to the case of FIG. 6(a) described above, the second operating member 24 needs to be rotated at a larger angle in order to remove the first operating member 23 from the first support member 26.

After the first operating member 23 is removed from the first support member 26, the situation is the same as when the operating part of the first operating member 23 breaks down in the most pushed-out state (as in Figures 6(b) and 6(c)). The first operating member 23 removed from the first support member 26 is supported by the member support part 27d. Then, as shown in Figures 7(b) and (c), the hook member 22 can be moved between the locked position P1 and the unlocked position P2 by releasing the force pulling the operating rope 24a or by pulling the operating rope 24a.

<Operation 3 of holding and releasing the jib by the second operating member>
Figure 8 is a diagram explaining the operation of the holding mechanism when the first operating member fails when the operating part is fully retracted, where (a) shows the process of releasing the first operating member, (b) shows the process of holding the jib, and (c) shows the process of releasing the hold on the jib.

If the first operating member 23 fails when the operating part is fully retracted, as shown in FIG. 8(a), the operating rope 24a is pulled manually or otherwise, transmitting force via the second operating member 24 and rotating the hook member 22 in the release direction. Then, since the operating part is fixed in the first operating member 23, the pulling force from the first operating member 23 to the first support member 26 disappears, and the first operating member 23 comes off the first support member 26 as shown in FIG. 8(a).

In the case of FIG. 8(a), the operating part of the first operating member 23 is fully retracted, so compared to the case of FIG. 7(a) described above, the second operating member 24 needs to be rotated at a larger angle to remove the first operating member 23 from the first support member 26. The movable range W2 in which the hook member 22 can be rotated by driving the second operating member 24 is smaller than the movable range W1 in which the hook member 22 can be rotated by operating the first operating member 23. Therefore, even when the operating part of the first operating member 23 is fully retracted, the first operating member 23 can be removed from the first support member 26 by pulling the operating rope 24a to the maximum.

After the first operating member 23 is removed from the first support member 26, the situation is the same as when the operating part of the first operating member 23 breaks down when it is fully pushed out (as in Figs. 6(b) and 6(c)), and when it breaks down when it is moderately pushed out (as in Figs. 7(b) and 7(c)). The first operating member 23 removed from the first support member 26 is supported by the member support part 27d. Then, as shown in Figs. 8(b) and (c), the hook member 22 can be moved between the locked position P1 and the unlocked position P2 by releasing the force pulling the operating rope 24a or by pulling the operating rope 24a.

As described above, according to the crane 1 of this embodiment, the holding mechanism 20 for holding the jib 14 includes the first operating member 23 and the second operating member 24 that can move the hook member 22. Furthermore, when the first operating member 23 becomes inoperable, the second operating member 24 can move the hook member 22 to the lock position P1 and the unlock position P2 regardless of the state of the first operating member 23. Therefore, it is possible to reduce the occurrence of a situation in which the holding and release of the holding of the jib 14 cannot be switched. Note that the above-mentioned "state of the first operating member 23" means various states in the operating mechanism of the first operating member 23, such as a state in which the operating part is fixed in various states, and does not include a state of the first operating member 23 due to the application of a physical disturbance, such as a wire being entangled in the first operating member 23.

Furthermore, according to the crane 1 of this embodiment, the first operating member 23 is configured to be operated by a drive, and the second operating member 24 is configured to be operated by manual force. Therefore, unless there is a malfunction, the first operating member 23 can be used to switch between holding and releasing the jib 14 without increasing the burden on the worker. Also, by configuring the second operating member 24 to be operated by manual force, the possibility of a malfunction occurring in the second operating member 24 can be greatly reduced, and therefore the occurrence of a situation in which it is impossible to switch between holding and releasing the jib 14 can be reduced.

The first and second operating members according to the present invention may both be configured to be actuated by a drive, or both may be configured to be actuated manually. Even in such a configuration, the presence of two operating members reduces the number of situations in which it is impossible to switch between holding and releasing the jib 14.

According to the crane 1 of this embodiment, the crane 1 further includes a first support member 26 that supports the first operating member 23, and the second operating member 24 is configured to detach the first operating member 23 from the first support member 26 when moving the hook member 22. By detaching the first operating member 23 from the first support member 26, the first operating member 23 can be prevented from interfering with the movement of the hook member 22 even if the first operating member 23 is stuck in any operating state. In addition, since the first operating member 23 detaches from the first support member 26 when the second operating member 24 moves the hook member 22, the number of parts can be reduced and the number of operation steps by the worker can be reduced compared to the case where a separate operation unit is provided to detach the first operating member 23 from the first support member 26.

Furthermore, according to this embodiment, a member support portion 27d is provided that separately supports the first operating member 23 that has become detached from the first support member 26. Therefore, even after the first operating member 23 becomes detached from the first support member 26, the position of the first operating member 23 is stable, and interference of the first operating member 23 with other members can be suppressed.

Furthermore, according to this embodiment, the member support portion 27d is attached to the hook member 22. Therefore, even if the hook member 22 rotates, the relative positional relationship between the first operating member 23 and the member support portion 27d does not change significantly. Therefore, the first operating member 23 that has come off the first support member 26 can be stably supported.

Furthermore, according to this embodiment, a member having a connecting portion 27b that connects the second operating member 24 to the hook member 22 and a member having a member support portion 27d are unitized and contained in a single stay 27. Therefore, the number of parts of the holding mechanism 20 can be reduced.

Furthermore, according to this embodiment, the movable range W2 of the hook member 22 caused by the operation of the second operating member 24 is greater than the movable range W1 of the hook member 22 caused by the operation (driving) of the first operating member 23. Therefore, even when the first operating member 23 is stuck in an actuated state in which it is most difficult to remove it from the first support member 26, the first operating member 23 can be removed from the first support member 26 by operating the second operating member 24.

Furthermore, according to this embodiment, the first operating member 23 is an electric actuator. Therefore, a power source (electricity) can be easily sent to the holding mechanism 20 located in the middle of the boom 13. Furthermore, the first operating member 23 is an electric actuator whose operating part is constrained to the base when no power is supplied. In this configuration, when power cannot be supplied, the operating part of the first operating member 23 is constrained to the base. However, according to this embodiment, even if power cannot be supplied to the first operating member 23 having such a configuration, the hook member 22 can be moved by operating the second operating member 24, which is particularly effective. Note that when the first operating member or the second operating member according to the present invention is configured to be operated by driving, it is not limited to an electric configuration, and a configuration driven by hydraulic pressure, liquid pressure, or air pressure may be adopted.

Furthermore, according to this embodiment, the second operating member 24 is an arm member to which the operating rope 24a is connected. Therefore, by utilizing the principle of leverage of the arm member, the jib 14 can be held or released with a relatively small force.

The above describes the embodiment of the present invention. However, the present invention is not limited to the above embodiment. For example, in the above embodiment, the crane is a tower crane, but the type is not limited as long as it is a crane equipped with a boom and a jib. For example, a fixed crane without a traveling function may be used. In the above embodiment, the hook member 22 is shown as an example of a locking member that can move between a locking position that holds the jib and an unlocking position that releases the hold of the jib. However, in a configuration in which the jib is held by inserting a lock pin into a lock hole and the hold of the jib is released by removing the lock pin, the locking member can be modified in various ways, such as by applying a lock pin as the locking member. In other words, the locking member may be any member as long as it can move between a locking position that holds the jib and an unlocking position that releases the hold of the jib. In the above embodiment, an example is shown in which the locking member is a rotating hook member, but the locking member may be configured to move in a translational manner. In such a configuration, the hook member may be read as a locking member and the rotation may be read as a movement in the description of the embodiment. In addition, the details shown in the embodiment can be modified as appropriate within the scope of the invention.

REFERENCE SIGNS LIST 1 crane 13 boom 14 jib 20 holding mechanism 21 base member 22 hook member (lock member)
22h Hook portion 22c Cam portion 22a Inclined portion 23 First operating member 24 Second operating member 24a Operating rope 25 Pressing member 26 First support member 27 Stay 27a Support portion 27b Connecting portion 27c Support portion 27d Member support portion (second support member)
31 Bar 40 Lock detection device P1 Lock position P2 Unlock position W1, W2 Movable range

Claims (8)

A crane comprising a boom, a jib attached to the boom so as to be able to be raised and lowered, and a holding mechanism for holding the jib in a folded state relative to the boom,
The holding mechanism includes:
A locking member movable between a locking position for holding the jib and an unlocking position for releasing the holding of the jib;
a first operating member and a second operating member that move the locking member to the lock position and the unlock position by their own drive or by receiving an external force;
having
the second operating member is configured to be able to move the locking member to the unlocking position regardless of a state of the first operating member when the first operating member cannot move the locking member to the unlocking position ,
Furthermore,
A first support member that supports the first operating member,
The second operating member is configured to disengage the first operating member from the first support member when the locking member is moved .
crane. The first operating member is actuated by its own drive,
The second operating member is operated by manual force.
The crane of claim 1. a second support member that further supports the first operating member in a state where the first operating member is removed from the first support member;
A crane as claimed in claim 1 or 2 . The second support member is attached to the locking member.
The crane of claim 3 . a movable range of the locking member caused by operation of the second operating member is larger than a movable range of the locking member caused by operation of the first operating member;
A crane as claimed in any one of claims 1 to 4 . The first operating member is an electric actuator.
A crane as claimed in any one of claims 1 to 5 . The second operating member is an arm member to which a rope is connected.
A crane as claimed in any one of claims 1 to 6 . The rope is a cable for transmitting power or signals;
The crane of claim 7 .

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