JP2018080011A - Mobile crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems of forming a gib base end into a fork shape which is necessitated by passing of a main hook through the base end during bulging/storing of a bottom hugging gib, and a reduction in strength/rigidity of the entire gib caused by low strength/rigidity against bending or torsion of the fork shaped part due to its open sectional structure.SOLUTION: A main hook holding member 21 is arranged in a gib 20, and a main hook 22 is held by the main hook holding member 21 when the gib 20 is at a gib work position. Thus, a gib base end 24 is shaped such that interference with a boom tip is prevented during rotation of the gib 20 and the length of a fork-shaped part is the shortest.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a mobile crane provided with a jib attached to and detached from the tip of a telescopic boom.

Several overhanging and retracting methods are known for the jib attached to and detached from the tip of the boom of the mobile crane.
After the jib base end is connected to the tip of the boom and suspended from the jib holding position held on the bottom of the boom with the base end of the jib facing the front of the boom, the tip of the jib is projected toward the front of the boom. A jib that can be displaced to a jib work position is known (Patent Document 1).
Hereinafter, this overhanging / storing type jib described in Patent Document 1 will be referred to as an “under-holding jib”.

  The underarm jib is used in urban areas because the jib suspended from the boom tip rotates around the boom's undulation surface with the boom tip as a fulcrum, requiring less space for overhanging and storing. It is used in many mobile cranes such as rough terrain cranes.

JP 2006-264958 A

However, as shown in FIG. 5, in the lower holding jib, the jib 8 is suspended from the boom tip during overhanging and retracting, so the main hook 1 suspended from the boom tip passes through the base end of the jib 8. There is a need to.
Therefore, the base end portion of the jib 8 must be bifurcated, and the space through which the main hook of the bifurcated portion passes needs to be large enough to allow the main hook 1 suspended from the tip of the boom 4 to pass. It was. Since the bifurcated portion has an open cross-sectional structure, the strength and rigidity against bending and torsion are low, resulting in a decrease in the strength and rigidity of the entire jib 8.

  Further, in the case of the telescopic lower-end holding jib, when the front-stage jib is stored in the base-stage jib, the base end (bifurcated portion) of the base-stage jib cannot be used as a storage space. Therefore, the total length of the front-stage jib is shorter than the total length of the base-stage jib. As a result, there has been a problem that the overall length of the jib is shortened when the front jib is extended.

Therefore, the present invention adopts a jib overhanging / storing method that does not require the main hook to pass through during overhanging / storing, so that the bifurcated part of the jib can be made smaller than in the past, and a high strength / rigid jib, Or it aims at providing the mobile crane provided with the expansion-contraction type jib which the jib full length at the time of expansion becomes large.

The mobile crane according to the first aspect of the present invention includes a boom that can be raised and lowered with respect to a vehicle, a main hook that is suspended from the tip of the boom, and a jib that is detachable from the tip of the boom. A jib lower position where the part is held in front of the boom and a lower side of the boom, and a jib work position where the jib tip is projected toward the front of the boom after the base end of the jib is connected to and suspended from the boom tip, The main hook holding member is disposed on the jib, and when the jib is in the jib working position, the main hook is held on the main hook holding member.
In the mobile crane of the first invention, when the jib is in the jib working position, the main hook is held by the main hook holding member, and it is not necessary to pass the jib base end of the main hook during overhanging / retraction. The bifurcated portion can be made smaller than before.

In the mobile crane according to the second aspect of the invention, the jib includes a jib distal end portion in which the sheave is rotatably arranged, a bifurcated jib proximal end portion connected to the boom distal end portion, a jib distal end portion, and a jib proximal end portion. And a jib base end that avoids interference with the tip of the boom when the jib rotates, and the length of the bifurcated portion is the shortest. The main hook holding member is disposed at the jib intermediate portion.
In the mobile crane according to the second aspect of the invention, the jib base end has a shape that avoids interference with the tip of the boom when the jib rotates and the length of the bifurcated portion is the shortest. The bifurcated portion can be made smaller than before, and a jib having high strength and rigidity can be obtained.

In the mobile crane according to the third aspect of the invention, the jib is a telescopic jib, the jib middle part has a box structure, and the box structure of the front stage side jib is fitted to the box structure of the base stage side jib so as to expand and contract. The
In the mobile crane of the third invention, the box structure of the base stage side jib and the box structure of the front stage side jib are made longer by the length of the bifurcated portion than before, so that the front stage side jib is made longer than before. Since it becomes long, the full length of the telescopic jib when extended can be lengthened.

  The mobile crane of the present invention eliminates the need to pass the jib base end of the main hook during overhanging and storing, so that the bifurcated portion of the jib can be made smaller than before, and the lower holding jib or jib that has high strength and rigidity. It is possible to provide a mobile crane provided with a telescopic lower-holding jib whose overall length is increased.

It is a figure which shows the state which hold | maintained the main hook with the main hook holding member arrange | positioned at the jib. FIG. 2 is a diagram showing the entire jib as viewed from the direction of arrow A in FIG. 1. It is a figure which shows the intermediate | middle attitude | position at the time of a jib overhang | projection and storage with which the jib base end part was connected and hung at the boom front-end | tip. It is a figure which shows the state which displaced the jib from the intermediate position of FIG. 3 to the jib work position projected toward the boom front. It is a figure which shows the state at the time of the overhang | projection and storage of the underarm jib described in patent document 1. FIG.

FIG. 1 is a view showing a state in which a main hook 22 is held by a main hook holding member 21 arranged on the jib 20. The jib 20 is in a jib work position where the tip of the jib 20 is projected toward the front of the boom 35, as shown in FIG. 1, approaching the jib base end portion 24 of the upper surface 25 of the jib intermediate portion 23 constituting the jib 20. The main hook holding member 21 is disposed at the position. The main hook holding member 21 includes a substrate 26, a receiving member 27, a support member 34, and a locking member 40 that are integrated.

The substrate 26 is welded to the upper surface 25 of the jib intermediate portion 23. The receiving member 27 has the same receiving shape as that of the side plate 29 of the main hook 22. By placing the main hook 22 on the receiving member 27, the main hook 22 is stably held by the main hook holding member 21.
A pair of support members 34 are erected on the substrate 26 with the main hook 22 interposed therebetween. A locking member 40 that can be contacted and released is disposed between the tip portions of the support members 34 and 34.
The main hook 22 is placed on the receiving member 27 in a state where the locking member 40 is released from the support member 34. Thereafter, the main hook 22 is held by the main hook holding member 21 by connecting the locking member 40.

The boom 35 shown in FIG. 1 is fully reduced. The boom head 37 of the top boom 36 is arranged with two plates facing each other in parallel, and a guide sheave 38 and a boom tip sheave 39 are rotatably arranged inside the boom head 37. Further, a single sheave 51 for hanging is rotatably disposed on the protruding portion 50 formed to protrude from the boom head 37.
Two side plates 29 are arranged on the main hook 22 so as to face each other in parallel, and a plurality of sheaves 53 are rotatably arranged inside the main hook 22.

FIG. 2 is a diagram showing the entire jib 20 as viewed in the direction of arrow A in FIG. 1. As shown in FIG. 2, four boom tip sheaves 39 are rotatably supported around the boom tip pin 54 on the boom head 37 at the tip of the top boom 36. In addition, a single hanging sheave 51 is rotatably disposed on the protruding portion 50 that is integrally formed by protruding from the boom head 37.

As shown in FIG. 2, the jib 20 connects the jib distal end portion 61, the jib proximal end portion 24, the jib distal end portion 61, and the jib proximal end portion 24 in which one sheave 60 is rotatably arranged. And a jib intermediate portion 23.
The jib base end portion 24 has a bifurcated shape and is connected to the top boom 36 across the boom head 37 and the protruding portion 50 of the single sheave 51 for suspension.
As shown in FIG. 1, the two most proximal ends 55 of the jib proximal end 24 are further bifurcated and connected to the boom distal pin 54 of the boom head 37.

As shown in FIG. 2, the jib base end 24 avoids interference with the boom tip when the jib 20 rotates about the boom tip pin 54, and the bifurcated portion has a length L1. The shape is the shortest.
The jib 20 of the present invention shown in FIG. 2 does not need to pass the main hook 22 as compared with the conventional under-holding jib that has to pass the main hook when the jib is extended. The length L1 of the part can be shortened. Thereby, the strength and rigidity of the jib 20 can be improved.

As shown in FIG. 2, the jib 20 is a telescopic jib, and the jib middle part 23 of the base stage side jib 57 has a box structure. The box structure 58 of the front stage side jib 56 is fitted in the box structure of the base stage side jib 57 so as to be extendable and contractible.
As can be seen from FIG. 2, if the total length L3 of the telescopic lower holding jib 20 is the same as that of the conventional jib, the length L1 of the bifurcated portion of the jib base end 24 is shortened. The length L2 of the front stage side jib 56 is extended.
Thereby, the jib full length of the expansion-contraction type jib 20 when it expand | extends can be made longer than the conventional expansion-contraction type jib.

In addition, 52 shown in FIG. 1 is a main wire drawn out from a main winch (not shown). The main wire 52 is routed between the boom tip sheave 39 and the sheave 53 of the main hook 22 after passing through the guide sheave 38 of the boom head 37.
As shown in FIG. 1, when the jib 20 is in the jib work position, the main wire 52 is loosened between the boom head 37 and the main hook 22 held by the jib 20.

FIG. 3 shows an intermediate position when the jib is extended and retracted, with the jib base end 24 connected to the boom tip 62 and suspended.
At this time, the outrigger 71 disposed on the vehicle 74 of the mobile crane 70 is overhanging. The boom 35, which is pivotally connected to a swivel 75 mounted on the vehicle 74 so as to be able to turn freely, is raised obliquely upward.
When the jib is extended, the jib 20 faces the front of the boom 35 through the intermediate position shown in FIG. 3 from the jib lower holding position where the jib base end 24 faces the front of the boom 35 and is held by the boom lower surface side 63. The jib 20 is displaced to the jib work position where the tip of the jib 20 is projected.
In the intermediate position shown in FIG. 3, the main hook 22 is held by the main hook holding member 21 arranged on the jib 20.

Various methods can be used for holding and releasing the main hook 22 by the main hook holding member 21 performed in the intermediate position shown in FIG. For example, the locking member 40 of the main hook holding member 21 shown in FIG. 1 may be moved by driving the hydraulic cylinder using hydraulic pressure when in the intermediate position shown in FIG. The driving of the locking member 40 is not limited to hydraulic pressure, and may be pneumatic pressure or electricity.
It is not limited to the power type as described above, but an operator who rides on an aerial work vehicle may perform a holding / releasing operation by manipulating the locking member 40 of the main hook holding member 21 by human power.

The structure of the main hook holding member 21 is not limited to that shown in FIG. 1, and various structures can be employed. For example, since the side plate 29 of the main hook 22 shown in FIG. 1 is normally a thick steel plate, a main hook holding device using an electromagnet may be arranged instead of the main hook holding member 21 of the jib 20. Good.
Then, when the jib 20 is in the jib work position, the main hook 22 can be held by the main hook holding device by energizing the electromagnet and attracting the side plate 29 of the main hook 22.

FIG. 4 shows a state in which the jib 20 is displaced from the intermediate position of FIG. 3 to the jib work position where the tip of the jib 20 is projected toward the front of the boom 35 and the boom 35 is raised.
As shown in FIG. 4, the main hook 22 is held by a main hook holding member 21 disposed on the jib 20. A sub wire 72 to which a sub hook 73 is attached is suspended from the jib tip 61.
In the state shown in FIG. 4, the jib work using the jib 20 by the mobile crane 70 is performed.

20: Jib 21: Main hook holding member 22: Main hook 23: Jib middle portion 24: Jib base end portion 35: Boom 56: Previous stage side jib 57: Base stage side jib 60: Sheave 61: Jib tip 70: Movement Type crane 74: vehicle

Claims (3)

A boom that can be raised and lowered with respect to the vehicle,
A main hook suspended from the tip of the boom;
A detachable jib at the tip of the boom,
The jib has a jib bottom holding position where the jib base end is directed toward the front of the boom and is held on the lower surface side of the boom, and after the jib base end is connected to the boom tip and suspended, the jib tip extends toward the front of the boom. It can be displaced to the jib work position to be released,
A mobile crane in which a main hook holding member is disposed on the jib and the main hook is held on the main hook holding member when the jib is in a jib working position. The jib is
A jib tip where the sheave is rotatably arranged;
A bifurcated jib base end connected to the boom tip;
A jib middle portion connecting the jib tip and the jib base end;
Consists of
The jib base end portion has a shape that avoids interference with the boom tip portion when the jib rotates, and the length of the bifurcated portion is the shortest. The mobile crane according to claim 1, wherein the mobile crane is disposed in an intermediate portion. The jib is a telescopic jib,
The mobile crane according to claim 2, wherein the jib intermediate portion has a box structure, and the box structure of the front stage side jib is telescopically fitted to the box structure of the base stage side jib.

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