JP2823825B2 - Crane boom hoist - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crane boom raising and lowering device, and more particularly to a crane boom raising and lowering device for reducing fatigue of a boom raising and lowering rope.

[0002]

2. Description of the Related Art FIG.
A boom 3 is attached to the front part of the boom 3 so as to be able to rotate back and forth, a top sheave 4 and a guide sheave 5 are pivotally mounted on the end of the boom 3, a hook rope 6 is wound around, and a hook 7 is suspended. And, by the winch unit 8 provided on the body 2,
The hook rope 6 is hoisted down and the hook 7 is moved up and down.

On the other hand, a high mast 9 is provided at the rear of the body 2. The high mast 9 includes a gate-shaped strut 10 pivotally attached to the front and rear, and a pair of left and right stays 11 for supporting the tip of the strut 10 from behind.
The stay 11 can be expanded and contracted by hydraulic pressure.

Further, one end of a boom pendant rope 12 is locked at the rear end of the boom 3, a bridle 13 is connected to the other end of the boom pendant rope 12, and a bail 14 is pivotally attached to the tip of the high mast 9. , Boom hoisting rope 1 between bridle 13 and bail 14
5 is wound and connected to the winch unit 8.

The lower portion of the rear surface of the boom 3 is supported by a backstop 16 so that the boom 3 does not exceed the maximum angle. When the winch unit 8 is driven to wind the boom hoisting rope 15, the distance between the bridle 13 and the bail 14 is gradually reduced from the minimum angle of the boom 3 within the working range shown by the solid line in FIG. Then, as shown by the two-dot chain line, the tip of the boom 3 is pulled backward through the boom pendant rope 12, and the boom 3 rotates backward to reach the maximum angle of the working range.

FIG. 6 shows the wiring of the boom hoisting rope 15, the position of the bridle 13 when the boom 3 is at the minimum angle is indicated by a solid line, and the position of the bridle 13 when the boom 3 is at the maximum angle is two points. Shown by chain lines.

Although the position of the guide sheave 5 actually moves up and down due to the ups and downs of the boom 3, the position of the guide sheave 5 is changed to the boom pendant rope 1 for convenience of explanation.
2 is translated.

If the distance between the bridle 13 and the bail 14 is reduced from L ₁ to L ₂ in order to raise the boom 3, any one point A ₁ of the boom hoisting rope 15 can be adjusted by the sheave of the bridle 13 and the bail 14. through 3 times the sheave moves to the position of a _2.

[0009]

The conventional crane 1 has the following features.
Bridle 13 and bail 1 when boom 3 is at maximum angle
Distance L ₂ between 4 is set in the permissible minimum dimension, thereby determines the length of the boom pendant rope 12. Also, the bridle 13 at the minimum angle of the boom 3 in the working range.
And it determines the spacing L ₁ also automatically with bail 14, when working the spacing between the bridle 13 and the bail 14 is changed in the range of L ₁ of L _2.

[0010] The angle of the boom 3 is changed by the boom hoisting rope 1
However, when the number of passes through the sheaves of the bridle 13 and the bail 14 increases, the boom hoisting rope 15 becomes fatigued and easily wears. Accordingly, the life of the boom hoisting rope 15 is shortened quickly, and an accident such as a breakage of the rope may occur.

Therefore, there arises a technical problem to be solved in order to reduce the number of passages of the boom hoisting rope through the sheave, prolong the service life of the boom hoisting rope, and prevent the occurrence of an accident. The purpose is to solve the problem.

[0012]

SUMMARY OF THE INVENTION The present invention has been proposed to achieve the above object, and has a boom mounted on a front part of a fuselage so as to be rotatable back and forth, and a high mast provided on a rear part of the fuselage. A crane connected to a bridle at the other end of the pendant rope, a bail is pivotally connected to the tip of the high mast, and a boom hoisting rope is wound between the bridle and the bail and connected to a winch unit.
An object of the present invention is to provide a crane boom hoisting device in which one end of a boom hoist cylinder is connected to the rear end of the boom tip, and one end of the boom pendant rope is connected to the other end of the boom hoist cylinder.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. For convenience of explanation, the same reference numerals are given to the same components as those in the related art, and the description is omitted.

FIG. 1 shows a crane 21 in which one end of a boom hoist cylinder 22 is connected to the rear end of the boom 3, and one end of a boom pendant rope 23 is connected to the other end of the boom hoist cylinder 22. This boom pendant rope 2
A bridle 13 is connected to the other end of the winch unit 3 and a boom hoisting rope 15 is wound between the bridle 13 and a bail 14 pivotally attached to the tip of the high mast 9 to winch unit 8.
Connect to

Here, when raising the boom 3 from the horizontal state, as shown in FIG. 2, the boom raising / lowering cylinder 22 is first extended to the maximum stroke position, the extension and retraction of the stay 11 is stopped, and the strut 10 is tilted backward. The high mast 9 is fixed so as to be in a state.

Next, the winch unit 8 is driven to wind up the boom hoisting rope 15 while the boom hoisting cylinder 2
2 is retracted, and as shown by the two-dot chain line in FIG.
Cause. Then, as shown in FIG. 3, if the boom hoist cylinder 22 is fixed in a contracted state to the minimum stroke position, the crane 21 becomes the working posture.

As described above, since the stroke of the boom hoist cylinder 22 is used to raise the boom 3 from the horizontal state, the initial distance between the bridle 13 and the bail 14 is reduced, and the amount of the boom hoist rope 15 extended is small. Therefore, the winding capacity of the drum of the winch unit 8 may be small.

Further, when the angle of the boom 3 is changed within the working range, the distance between the bridle 13 and the bail 14 is increased and decreased by driving the winch unit 8 to raise and lower the boom hoisting rope 15. The boom 3 rotates back and forth. For example, when the boom hoisting rope 15 is hoisted, the tip of the boom 3 is pulled rearward through the boom hoisting cylinder 22 and the boom pendant rope 23, as shown by the two-dot chain line in FIG. Rotates and stands up to the maximum angle of the working range.

FIG. 4 shows the wiring of the boom hoisting rope 15, the position of the bridle 13 when the boom 3 is at the minimum angle is indicated by a solid line, and the position of the bridle 13 when the boom 3 is at the maximum angle is indicated by two points. Shown by chain lines.

Although the position of the guide sheave 5 actually moves up and down due to the up and down movement of the boom 3, the position of the guide sheave 5 is moved in parallel along the boom up and down cylinder 22 for convenience of explanation.

If the distance between the bridle 13 and the bail 14 is reduced from L ₃ to L ₄ in order to raise the boom 3, any one point A ₁ of the boom hoisting rope 15 passes once through the sheave of the bridle 13. moves to the position of a ₂ and.

A comparison between the wiring of the boom hoisting rope 15 shown in FIG. 4 and the conventional example shown in FIG.
Is changed from the minimum angle to the maximum angle, the extension amount of the boom hoisting rope 15 is the same in both cases. However, the initial distance between bridle 13 and bail 14 is L ₃
> Is L _1, also for the last interval is L _4> L _2, fatigue of the rope reduces the sieve pass count of the boom hoist cable 15 is reduced, the life of the boom pivoting rope 15 is longer.

The present invention can be variously modified without departing from the spirit of the present invention, and it is natural that the present invention extends to the modified ones.

[0024]

As described above, in the present invention, when the boom is raised and lowered in the range of the working posture, the fatigue of the rope is reduced by reducing the number of sheave passages of the boom raising and lowering rope. In this way, the life of the boom hoist rope is prolonged, the durability is improved, and safety can be ensured.

[Brief description of the drawings]

FIG. 1 is a side view of a crane in a working posture state, showing an embodiment of the present invention.

FIG. 2 is a side view of the crane when raising the boom from a horizontal state.

FIG. 3 is a side view of the crane for explaining a change in a boom angle in a working posture.

FIG. 4 is an explanatory view showing wiring of a boom hoisting rope.

FIG. 5 is a side view of a conventional crane.

FIG. 6 is an explanatory view showing wiring of a boom hoisting rope of a conventional crane.

[Explanation of symbols]

 2 body 3 boom 8 winch unit 9 high mast 13 bridle 14 bail 15 boom hoisting rope 21 crane 22 boom hoisting cylinder 23 boom pendant rope

Claims (1)

(57) [Claims] 1. A boom is rotatably mounted on a front part of a fuselage, a high mast is provided on a rear part of the fuselage, a bridle is connected to the other end of a boom pendant rope, and a bail is pivotally attached to a tip of the high mast. In a crane in which a boom hoist rope is wound between a bridle and a bail and connected to a winch unit, one end of a boom hoist cylinder is connected to the rear end of the boom, and the other end of the boom hoist cylinder is connected to the other end of the boom hoist cylinder. A crane boom raising / lowering device, wherein one end of a pendant rope is connected.