JP2022150624A - crane - Google Patents

Abstract

To provide a crane capable of reducing the occurrence of a situation in which it is impossible to switch between the holding of a jib and the releasing of the holding.SOLUTION: A crane includes a boom, a jib mounted on the boom to be raised and lowered, and a holding mechanism (20) for holding the jib in a folded state with respect to the boom. The holding mechanism (20) includes a lock member (22) movable between a lock position (P1) in which the jib is held and a lock releasing position (P2) in which the holding of the jib is released and a first operation member (23) and a second operation member (24) receiving force by driving or from the outside to move the lock member between the lock position and the lock releasing position. When the first operation member (23) becomes inoperable, the second operation member (24) is configured to move the lock member (22) between the lock position (P1) and the lock releasing position (2) regardless of the mode of the first operation member (23).SELECTED DRAWING: Figure 4

Description

The present invention relates to cranes.

Patent Literature 1 discloses a jib mooring device that can hold and release the jib by an actuator, and that can manually hold and release the jib even if the actuator becomes inoperable. .

Japanese Patent No. 6756239

However, in the jib mooring device described above, if the actuator is stuck and becomes inoperable, it becomes impossible to manually switch between holding and releasing the jib.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the occurrence of a situation in which it is impossible to switch between holding a jib and releasing the holding.

A crane according to the present invention includes:
A crane comprising a boom, a jib hoistably attached to the boom, and a holding mechanism holding the jib in a folded state with respect to the boom,
The holding mechanism is
a locking member movable between a lock position for holding the jib and an unlock position for releasing the holding of the jib;
a first operating member and a second operating member for moving the locking member between the locking position and the unlocking position by being driven by itself or by receiving a force from the outside;
has
When the lock member cannot be moved to the unlock position by the first operation member, the second operation member is configured to operate the lock member to unlock regardless of the mode of the first operation member. configured to be movable into position;

According to the present invention, it is possible to reduce the occurrence of a situation in which it is impossible to switch between holding the jib and releasing the holding.

It is a side view showing a crane concerning an embodiment of the present invention. It is the top view (a), front view (b), and side view (c) which show the holding|maintenance mechanism of embodiment. It is a rear perspective view which shows the 1st support member of a holding|maintenance mechanism. It is a figure explaining the locking position (a) and unlocking position (b) of a hook member. FIG. 10 is a diagram for explaining the operation of holding and releasing the jib by operating the first operating member, and (a) to (c) are diagrams showing steps of the operation. FIG. 10A is a diagram for explaining the operation of the holding mechanism when the first operating member fails when the operating portion is pushed out to the maximum, and (a) is a step of removing the first operating member and (b) is a step of holding the jib. , (c) shows the step of releasing the holding of the jib. FIG. 4A is a diagram for explaining the operation of the holding mechanism when the first operating member fails while the operating portion is moderately pushed out, and FIG. 4A is a step of removing the first operating member, and FIG. (c) shows the step of releasing the holding of the jib. FIG. 10B is a diagram for explaining the operation of the holding mechanism when the first operating member fails when the operating portion is retracted to the maximum; (a) is the step of removing the first operating member; , (c) shows the step of releasing the holding of the jib. FIG. 4 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.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 is a side view showing a crane according to an embodiment of the invention; FIG. FIG. 1 shows the folded state of the jib 14 in solid lines and the upright state of the jib 14 in two-dot chain lines.

The crane 1 of this embodiment includes a lower structure 11, an upper revolving structure 12 that rotates with respect to the lower structure 11, a boom 13 that is connected to the upper revolving structure 12 so that it can be raised and lowered, and a boom that can be raised and lowered. a jib 14 connected to the jib, a hook 15 suspended from the jib via a wire rope L, a holding mechanism 20 capable of holding the jib 14 in a folded state with respect to the boom 13, and an operation operation from the operator. and a driver's cab 18 having a driver control for receiving.

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 stands up 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 revolving body 12 is provided with a plurality of winches U for winding or feeding wire ropes for raising and lowering the boom 13, raising and lowering the jib 14, and raising and lowering the hook 15. As shown in FIG. An operation means (operation button or the like) for driving the first operation member (electric actuator) 23 of the holding mechanism 20 may be arranged in the operator's cab 18 .

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

The holding mechanism 20 is a mechanism whose main part is attached to the boom 13 and which can hold and release the jib 14 in a state where the jib 14 is folded with respect 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 rotatably supported by the base member 21, and a rotating shaft 22x connecting the left and right hook members 22. , a first operating member 23 capable of moving the hook member 22 by being driven by itself, a second operating member 24 capable of moving the hook member 22 by receiving force from the outside, and rotating the hook member 22. A biasing member (for example, a coil spring) 25 that biases in one direction of movement, a first support member 26 that detachably supports one end of the first operation member 23, a stay 27 that supports each member, and a jib. A bar 31 connected to 14 main or auxiliary members. The hook member 22 corresponds to an example of the locking member according to the invention.

The stay 27 includes a support portion 27a that rotatably supports one end of the first operation member 23, a connection portion 27b that connects the second operation member 24, a support portion 27c that supports the biasing member 25, and a member supporting portion 27d that supports the first operating member 23 when the first operating member 23 is detached from the first supporting 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 invention.

The hook member 22 includes a hook portion 22h that can be hooked on the bar 31 to restrain the bar 31, a cam portion 22c that is located closer to the rotation shaft than the hook portion 22h and can be brought into contact with the bar 31, and a rotation-side cam portion 22c. and an inclined portion 22a located at the edge (see FIG. 4(a)).

The hook member 22 has a lock position P1 at which the bar 31 can be held, as shown in FIG. 4(a), and an unlock position P2, at which the bar 31 is released from being held, as shown in FIG. 4(b). It is movable (rotatable). Holding the bar 31 means holding the jib 14 to which the bar 31 is connected. Releasing the holding of the bar 31 means releasing the holding of the jib 14 to which the bar 31 is connected. The hook member 22 rotates along a plane intersecting the longitudinal direction of the bar 31 . At the lock position P1, the hook portion 22h is positioned on the movement path of the bar 31 (movement path associated with the rotation of the jib 14), and when the bar 31 is positioned within the hook portion 22h, the bar 31 is separated from the hook member 22. The hook member 22 is hooked on the bar 31 so that the bar 31 does not come off the hook member 22 even when the hook member 22 is moved in the direction to move. At the unlocked position P2, the hook portion 22h is removed from the movement path of the bar 31 (the movement path associated with the rotation of the jib 14). Hereinafter, among the rotation directions of the hook member 22, the direction from the unlocked position P2 to the locked position P1 will be referred to as the "locking direction", and the direction from the locking position P1 to the unlocked position P2 will be referred to as the "releasing direction".

When the hook member 22 is at the unlocked position P2, the cam portion 22c exerts a force in the locking direction on the hook member 22 by contacting the bar 31 due to movement of the bar 31 as the jib 14 falls.

When the hook member 22 is at the lock position P1, the inclined portion 22a exerts a force in the releasing direction on the hook member 22 by contacting the bar 31 due to movement of the bar 31 as the jib 14 falls.

The biasing member 25 generates a biasing force between the base member 21 and the hook member 22 and applies force to the hook member 22 in the locking direction. 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 lock position P1. A portion of the biasing member 25 is connected to the base member 21 and the other portion 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 actuating portion and can move (eg push and retract) the actuating portion with respect to the base. 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 an operating portion. With such a configuration, it is possible to generate a large pulling force or pushing force electrically, and it is possible to obtain the characteristic that the operating part does not easily move against external force.

The first operating member 23 has one of its base portion and operating portion supported by the first support member 26 and the other supported by the hook member 22 via the stay 27 . The first operating member 23 is rotatably supported with respect to the stay 27 and rotatably supported with respect to the first support member 26 . Therefore, a force in the releasing direction can be applied to the hook member 22 by generating a force that attracts the operating portion to the first operating member 23 .

A movable range W1 of the hook member 22 by operating (driving) the first operating member 23 includes a lock position P1 and an unlock position P2. In FIG. 4B, the movable range W1 of the hook member 22 is represented by the variation range of the angle of the central axis of the second operating member 24. As shown in FIG.

As shown in FIG. 3, the first support member 26 has a groove frame 26a with at least one open end. 1 Supports a portion of the operating member 23 . The first supporting member 26 supports the first operating member 23 when the projecting portion 23 a of the first operating member 23 is pulled toward the stay 27 . On the other hand, when there is no pulling force and the stay 27 and the first support member 26 come close to each other, the projecting portion 23a of the first operation member 23 is disengaged from the groove frame 26a, so that the first operation member 23 moves toward the first support member. 26 can be removed.

The second operating member 24 is an arm member connected to the hook member 22 via a stay 27, and is connected to an operating rope 24a. An 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 extending linearly, a member extending along a curved path, or the like. . By manually pulling the operating rope 24a, the second operating member 24 can apply force to the hook member 22 in the releasing direction. The operation rope 24a may be, for example, a power supply or signal cable (not shown) for driving the first operation member 23. FIG. Alternatively, the operating rope 24a may be a cable (not shown) for power supply or signal for 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 connected to the main body of the crane 1 and the lock detection device 40, and transmit power or signals. Therefore, the middle portion of the cable can be connected to the second operating member 24 . Even with such a configuration, by manually pulling the cable, a force can be applied to the second operating member 24 in a direction to release the hook member 22 . In this case, the number of parts of the holding mechanism 20 can be reduced, and the number of assembly man-hours can also be reduced.

A movable range W2 (see also FIG. 8A) of the hook member 22 by the operation (rotating operation) of the second operating member 24 includes the lock position P1 and the unlock position P2. Further, the movable range W2 is larger than the movable range W1 of the hook member by operating the first operating member 23 . 4(b) and 8(a), the movable range W2 of the hook member 22 is represented by the variation range of the angle of the central axis of the second operating member 24. As shown in FIG.

FIG. 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.

A lock detection device 40 is attached to the left hook member 22 . The left hook member 22 is arranged on the opposite side to the right hook member 22 where the first operating member 23 is arranged. The lock detection device 40 detects that the hook member 22 has reached the lock position P1. The lock detection device 40 includes a limit switch 41 for detecting that the bar 31 is held when the hook member 22 is at the lock position P1, a detection lever 42 capable of operating the switch of the limit switch 41, and a detection lever 42 and a detection lever holding member (spring) 43 that holds the bar 31 so as to be in contact with the bar 31 .

The detection lever 42 is rotatably supported with respect to the hook member 22 . At the unlocked position P<b>2 , the detection lever 42 is biased by the detection lever holding member 43 so as not to contact the switch portion 41 a of the limit switch 41 . When the hook member 22 moves toward the lock position P1, the detection lever 42 contacts the bar 31 and rotates toward the limit switch 41 side. When the hook member 22 moves to the lock position P1, the detection lever 42 pushes the switch portion 41a of the limit switch 41, and the limit switch 41 outputs an ON signal. From the ON signal, it can be determined that the bar 31 is held. A display (not shown) in the operator's cab 18 indicates that the jib 14 is locked (holding of the jib 14) based on the ON signal of the limit switch 41. FIG.

<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 (a) to (c) are diagrams showing steps 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 called the "approaching direction", and the direction in which the jib 14 separates from the boom 13 is called the "separating direction".

As shown in FIG. 5(a), when the hook member 22 is at the locking position P1 and the bar 31 is positioned within the hook portion 22h, the restrained state of the bar 31 and the jib 14 is maintained unless the lock is unlocked. be done. That is, even if the jib 14 and the bar 31 try to move in the separation direction, 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 to generate a force 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). When the drive amount (attraction drive amount) of the first operating member 23 is maximum, as shown in FIG. , the hook portion 22h is released, and the jib 14 is unlocked. At this time, a force is applied to the jib 14 to make it stand up, so that the jib 14 can be rotated in the separation direction. The movable range W1 ranges from the angle of the hook member 22 when the drive amount of the first operating member 23 is zero (the most extended state) to the angle when the first operating member 23 is maximized (the most contracted state). It corresponds to the range up to the angle of the hook member 22 .

When holding the jib 14 from the state in which the holding of the jib 14 is released, first, the first operating member 23 is driven as shown in FIG. 5(c). By folding the jib 14, the bar 31 is moved to a position where it can be accommodated in the hook portion 22h. After that, by pushing out the operating portion of the first operating member 23 as shown in FIGS. 5(b) and 5(a), the bar 31 is restrained in the hook portion 22h, and the jib 14 can be held in the folded state. .

When the jib 14 is folded, the bar 31 contacts the cam portion 22c of the hook member 22 as the bar 31 moves further in the approaching direction. Due to this abutment, a force in the locking direction is applied to the hook member 22, and the retraction of the operating portion of the first operating member 23 and the rotation of the hook member 22 in the locking direction can be realized smoothly.

5(a) to 5(c), a force in the locking direction is applied to the hook member 22 by the biasing member 25 (see FIG. 2(c)), and the first support member 26 is Since the force that pulls the first operating member 23 acts, the projecting portion 23a of the first operating member 23 does not come off from the groove frame 26a (see FIG. 3) of the first supporting member 26. As shown in FIG.

<Example of failure of the first operation member>
When the first operating member 23 (electric actuator) fails, the state of the first operating member 23 varies depending on the timing of the failure. For example, if a failure occurs at the stage of FIG. 5(a), the first operating member 23 will harden in a state in which the operating portion is pushed out to the maximum. If the failure occurs at the stage of FIG. 5(b), the first operating member 23 will harden in a state in which the operating portion is moderately pushed out. In the event of failure at the stage of FIG. 5(c), the first operating member 23 is solidified with the operating portion retracted to the maximum.

On the other hand, according to the holding mechanism 20 of the present embodiment, as described below, even when the first operating member 23 fails at any stage, the second operating member 24 is operated to hold and hold the jib 14. can be released.

<Operation 1 for holding and releasing the jib by the second operating member>
6A and 6B are diagrams for explaining the operation of the holding mechanism when the first operating member fails when the operating portion is pushed out to the maximum. (c) shows a step of releasing the holding of the jib.

When the first operating member 23 fails in the state in which the operating portion is pushed out to the maximum, as shown in FIG. is transmitted, and the hook member 22 rotates in the releasing direction. Then, since the operating portion of the first operating member 23 is solidified, the pulling force from the first operating member 23 to the first supporting member 26 disappears, and the first operating member 23 moves as shown in FIG. 6(a). comes off the first support member 26 . That is, the protruding portion 23a of the first operating member 23 moves along the groove frame 26a of the first support member 26 and is removed from one end side of the groove frame 26a. The first operating member 23 removed from the first operating member 23 rotates around the supporting portion 27a according to gravity, and comes into contact with the member supporting portion 27d of the stay 27 and stops. That is, the member supporting portion 27d supports the first operating member 23 on one side. Since the member supporting portion 27d is fixed to the hook member 22, even if the hook member 22 rotates, the relative angle between the hook member 22 and the first operating member 23 supported by the member supporting portion 27d does not change. Therefore, the member support portion 27d can continuously support the first operation member 23 at an angle that does not interfere with other members (the first support member 26, etc.) regardless of the rotational position of the hook member 22. FIG.

Since the failed first operating member 23 is removed from the first supporting 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 thereafter. operation can be performed.

For example, as shown in FIG. 6B, the hook member 22 can be rotated to the lock position P1 by the biasing force of the biasing member 25 when the operation rope 24a is stopped being pulled. At this time, since the bar 31 is positioned so as to be accommodated within the hook portion 22h, the bar 31 can be restrained within the hook portion 22h and the jib 14 can be held in a folded state.

When the jib 14 is to be held in the folded state when the first operating member 23 has failed, the jib 14 is rotated to move the bar 31 in the approaching direction without pulling the operating rope 24a. good too. As a result of this movement, when the bar 31 comes into contact with the inclined portion 22a of the hook member 22, 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 being held, the hook member 22 rotates in the releasing direction via the second operating member 24 by pulling the operating rope 24a largely, as shown in FIG. 6(c). Then, the hook member 22 rotates to the lock release position P2, and the hook portion 22h is removed from the moving path of the bar 31, so that the restraint of the bar 31 is released and the jib 14 is released from being held.

The member supporting portion 27d is positioned so that the first operating member 23 does not return to the state of being supported by the first supporting member 26 no matter how the operating rope 24a is pulled or returned. support.

<Operation 2 for holding and releasing the jib by the second operating member>
7A and 7B are diagrams for explaining the operation of the holding mechanism when the first operating member fails while the actuating portion is moderately pushed out, and FIG. 7A is the step of removing the first operating member; indicates the step of holding the jib, and (c) indicates the step of releasing the holding of the jib.

When the first operating member 23 fails in a state in which the operating portion is pushed out moderately, as shown in FIG. force is transmitted to the hook member 22, and the hook member 22 rotates in the release direction. Then, since the operating portion of the first operating member 23 is solidified, the pulling force from the first operating member 23 to the first supporting member 26 disappears, and the first operating member 23 moves as shown in FIG. 7(a). comes off the first support member 26 .

In the example of FIG. 7(a), the actuation portion of the first operating member 23 is retracted to the middle extent, so compared to the case of FIG. In order to disengage from member 26, second operating member 24 must be pivoted through a large angle.

After the first operating member 23 is removed from the first supporting member 26, when the operating portion of the first operating member 23 is pushed out to the maximum and fails (in the case of FIGS. 6(b) and 6(c), ). The first operation member 23 removed from the first support member 26 is supported by the member support portion 27d. Then, as shown in FIGS. 7B and 7C, the hook member 22 is moved between the lock position P1 and the unlock position P2 by releasing the pulling force of the operation rope 24a or by pulling the operation rope 24a. can be moved to

<Operation 3 for holding and releasing the jib by the second operating member>
8A and 8B are diagrams for explaining the operation of the holding mechanism when the first operating member fails when the operating portion is retracted to the maximum, and FIG. (c) shows a step of releasing the holding of the jib.

When the first operating member 23 fails when the operating portion is retracted to the maximum, as shown in FIG. is transmitted, and the hook member 22 rotates in the releasing direction. Then, since the operating portion of the first operating member 23 is solidified, the pulling force from the first operating member 23 to the first supporting member 26 disappears, and the first operating member 23 moves as shown in FIG. 8(a). comes off the first support member 26 .

In the case of FIG. 8(a), since the actuation portion of the first operating member 23 is retracted most, the first operating member 23 is moved away from the first support member 26 as compared with the case of FIG. 7(a) described above. For removal, the second operating member 24 must be rotated through a large angle. A movable range W2 within which the hook member 22 can be rotated by driving the second operating member 24 is smaller than a movable range W1 within which the hook member 22 can be rotated by operating the first operating member 23 . Therefore, even when the operating portion 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 supporting member 26, when the operating portion of the first operating member 23 is pushed out to the maximum and fails (in the case of FIGS. 6(b) and 6(c), ), and the case where the working part fails in a moderately pushed state (cases of FIGS. 7(b) and 7(c)). The first operation member 23 removed from the first support member 26 is supported by the member support portion 27d. Then, as shown in FIGS. 8B and 8C, the hook member 22 is moved between the lock position P1 and the unlock position P2 by releasing the pulling force of the operation rope 24a or by pulling the operation rope 24a. can be moved to

As described above, according to the crane 1 of this embodiment, the holding mechanism 20 that holds the jib 14 includes the first operating member 23 and the second operating member 24 that can move the hook member 22 . Further, the second operating member 24 moves the hook member 22 between the lock position P1 and the unlock position P2 regardless of the mode of the first operating member 23 when the first operating member 23 becomes inoperable. be able to. Therefore, it is possible to reduce the occurrence of a situation in which switching between holding and releasing the jib 14 becomes impossible. Note that the above-mentioned "mode of the first operating member 23" means various modes of the operating mechanism of the first operating member 23, such as modes in which the operating portion is fixed in various states. It does not include the aspect of the first operating member 23 due to physical disturbance such as entanglement with the member 23 .

Furthermore, according to the crane 1 of the present embodiment, the first operating member 23 is configured to be actuated by driving, and the second operating member 24 is configured to be manually actuated. Therefore, if there is no failure, the jib 14 can be held and released by using the first operating member 23 without increasing the load on the operator. In addition, by configuring the second operating member 24 to be manually operated, the possibility of malfunction of the second operating member 24 can be greatly reduced, so that holding and releasing of the jib 14 can be switched. Fewer disabling situations occur.

It should be noted that the first and second operating members according to the present invention may both be driven and actuated, or both may be manually actuated. Even with such a configuration, it is possible to reduce situations in which it is impossible to switch between holding the jib 14 and releasing the holding because there are two systems of operation members.

According to the crane 1 of the present embodiment, the first support member 26 that supports the first operating member 23 is further provided, and the second operating member 24 moves the first operating member 23 to the second position when the hook member 22 is moved. 1 support member 26. The first operating member 23 is removed from the first support member 26 so that the first operating member 23 does not interfere with the movement of the hook member 22 even if the first operating member 23 is stuck in any operating state. can be done. Further, when the second operating member 24 moves the hook member 22, the first operating member 23 is disengaged from the first supporting member 26. Therefore, in order to disengage the first operating member 23 from the first supporting member 26, another operating member is required. Compared to the case of providing , it is possible to reduce the number of parts and the number of operation steps by workers.

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

Furthermore, according to this embodiment, the member supporting portion 27d is attached to the hook member 22. As shown in FIG. 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 operation member 23 detached from the first support member 26 can be stably supported.

Furthermore, according to the present embodiment, the member having the connecting portion 27b that connects the second operating member 24 to the hook member 22 and the member having the member supporting portion 27d are unitized into one stay 27. ing. Therefore, the number of parts of the holding mechanism 20 can be reduced.

Furthermore, according to the present embodiment, the movable range W2 of the hook member 22 by operating the second operating member 24 is larger than the movable range W1 of the hook member 22 by operating (driving) the first operating member 23 . Therefore, even when the first operating member 23 is frozen in an operating state in which it is most difficult to come off the first supporting member 26, the first operating member 23 can be removed from the first supporting member 26 by operating the second operating member 24. .

Furthermore, according to this embodiment, the first operating member 23 is an electric actuator. Therefore, the power source (electric power) 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 portion is restrained with respect to the base portion when electric power is not supplied. With such a configuration, the actuating portion of the first operating member 23 is restrained by the base portion when electric power cannot be supplied. However, according to this embodiment, the hook member 22 can be moved by operating the second operating member 24 even if power cannot be supplied to the first operating member 23 having such a configuration, which is particularly effective. In addition, when the first operation member or the second operation 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, hydraulic 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, using the principle of leverage by the arm member, the jib 14 can be held or released with a relatively small force.

The embodiments of the present invention have been described above. However, the invention is not limited to the above embodiments. For example, in the above-described embodiment, the crane is a tower crane, but the type is not limited as long as the crane has a boom and a jib. For example, a stationary crane that does not have a travel function may be used. Further, in the above-described embodiment, the hook member 22 is shown as an example of a lock member that can move between the lock position for holding the jib and the unlock position for releasing the hold of the jib. However, for example, in a structure in which the jib is held by inserting a lock pin into the lock hole and released from holding by pulling out the lock pin, the lock pin can be used as the lock member. can be changed to That is, the locking member may be any member as long as it can move between a locked position for holding the jib and an unlocked position for releasing the holding of the jib. In the above embodiment, an example in which the lock member is a hook member that rotates is shown, but the lock member may be configured to move in translation. In the case of such a configuration, in the description of the embodiment, the hook member may be read as the lock member, and the rotation may be read as the movement. Other details shown in the embodiments can be changed as appropriate without departing from 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 biasing member 26 first supporting member 27 stay 27a supporting portion 27b connecting portion 27c supporting portion 27d member supporting portion (second supporting portion) Element)
31 Bar 40 Lock detector P1 Lock position P2 Unlock position W1, W2 Movable range

Claims (9)

A crane comprising a boom, a jib hoistably attached to the boom, and a holding mechanism holding the jib in a folded state with respect to the boom,
The holding mechanism is
a locking member movable between a lock position for holding the jib and an unlock position for releasing the holding of the jib;
a first operating member and a second operating member for moving the locking member between the locking position and the unlocking position by being driven by itself or by receiving a force from the outside;
has
When the lock member cannot be moved to the unlock position by the first operation member, the second operation member is configured to operate the lock member to unlock regardless of the mode of the first operation member. configured to be movable into position,
crane. The first operating member is operated by its own drive,
the second operating member is actuated by manual force;
A crane according to claim 1. A first support member that supports the first operation member,
The second operating member is configured to disengage the first operating member from the first support member when moving the locking member.
A crane according to claim 1 or claim 2. a second support member that further supports the first operation member in a state detached from the first support member;
A crane according to claim 3. the second support member is attached to the locking member;
A crane according to claim 4. a movable range of the lock member by operating the second operating member is larger than a movable range of the locking member by operating the first operating member;
A crane as claimed in any one of claims 3 to 5. The first operating member is an electric actuator,
A crane according to any one of claims 1 to 6. The second operating member is an arm member to which a rope is connected,
A crane according to any one of claims 1 to 7. The rope is a cable that transmits power or signals,
A crane according to claim 8.

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