JPH0626591Y2 - Drag line fairlead - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a drag line fair lead for excavating work by attaching a drag line bucket to a mobile crane.

[Conventional technology]

The drag line is for carrying out excavation work by attaching a drag line bucket to a mobile crane. As shown in FIG. 4, the drag rope 6 that pulls the drag line bucket 5 from the winch 3 of the crane body 1 to the fair lead 4 is used.
It is connected to the drag line bucket 5 via. The fair lead 4 is provided in order to prevent the drag rope 6 from being wound around the winch 3 irregularly, so that the drag line bucket 5 may be swung by the turning of the crane body 1. The upper and lower sheaves and the pair of left and right rollers are rotatably attached to a frame that is rotatably attached to the front portion via a housing. A sheave having a large rope center diameter is attached to the fair lead 4 in order to cope with the deflection of the drag rope 6 in all directions and to minimize the abrasion due to the local bending of the drag rope 6. 16
Is a support rope.

[Problems to be solved by the device]

The conventional fair lead 4 has no means for restricting the attitude of the frame. Therefore, when the boom 2 is lowered as shown in FIG. I have hit 2.

Therefore, the angle at which the boom 2 is lowered is limited, and a limit switch (not shown) is attached as the limiting means. Further, in order to descend the boom 2 to the ground, the fair lead 40 is removed, or as shown in FIG. 6, the fair lead 40 is rotatably attached to the front portion of the crane main body 1 via a pin 43. Link 4 with a long hole
1 and a pin 42 movably mounted in the long hole
Therefore, it is necessary to provide a fair lead lowering means capable of changing the position of the fair lead 40 between the working position indicated by the two-dot chain line and the lowering position indicated by the solid line.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to make it possible to always maintain the frame of the fair lead in a constant posture when the drag rope is not tensioned. The problem is to solve the above-mentioned problems.

[Means for Solving the Problems]

In order to achieve this object, the present invention provides a housing attached to the front of a mobile crane body, a frame rotatably attached to the housing, and two upper and lower rotatably attached to the frame. Having a sheave and a pair of right and left rollers, between the rollers and between the sheaves,
In the fair line of the drag line, which is configured to prevent irregular winding of the drag rope winding winch by inserting the drag rope attached to the drag line bucket, a weight increasing portion is provided on one sheave side of the frame. When the tension is not applied to the drag rope, the posture of the frame is regulated by the weight of the weight increasing portion so that the sheave faces the vertical direction.

[Action]

Since the present invention is configured as described above, it can cope with the runout of the drag rope inserted between the rollers and the sheaves in all directions at the time of working, and when the drag rope is not under tension and when not working. At times, the posture of the frame is regulated by the weight of the weight increasing portion formed on one sheave side of the frame so that the sheave is positioned in the vertical direction. Therefore, even if the boom is lowered, the fair lead does not hit the boom.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.
A more specific description will be given. In FIGS. 1 to 3, the same reference numerals as those in FIG. 4 designate the same or corresponding components. The fair lead 4 has a housing 7 attached to the center of the boom 2 in the front part of the crane body 1, and the inner periphery of the housing 7 is provided with bearings 8 and 9 on the attachment portion 10 a of the frame 10.
Is rotatably attached. Two sheaves 11 and 12 on the upper and lower sides and a pair of left and right rollers 13 and 14 located in front of the sheaves are rotatably attached to the frame 10, respectively. A weight 15 is attached to one sheave 12 side of the frame 10. Then, as described above, the dragline rope 6 attached to the dragline bucket 5 passes between the rollers 13 and 14 and between the sheaves 11 and 12, that is, the winch 3 installed in the crane body 1 through the frame 10. It has been wound up.

During the drag line work, the drag rope 6 fed from the winch 3 is connected to the drag line bucket 5 through the frame configured to be rotatable.
The drag rope 6 is pulled by the movement of the drag line bucket 5, and the frame 10 rotates in the pulling direction. At this time, the drag rope 6 located between the winch 3 and the fair lead 4 has two sheaves 11,
Winding with a winch 3 while the position is regulated between 12
Since the pay-out can be performed, irregular winding of the drag rope 6 around the winch 3 is prevented. Also, fair lead 4
The drag rope 6 positioned between the drag line bucket 5 and the drag line bucket 5 is orthogonal to the swing of the drag rope 6 in any direction by the pair of left and right rollers 13 and 14 and the upper and lower sheaves 11 and 12. Since the minimum bending radius is regulated by the large diameter sheaves 11 and 12, the drag rope 6 is not locally bent. When the drag rope 6 loses its tension, the weight of the weight 15 attached to the frame 10 on the one sheave 12 side restricts the posture of the frame 10 in a position where the two sheaves 11 and 12 face in the vertical direction. . As a result, even if the boom 2 is lowered as shown in FIGS. 3 and 4, the boom 2 does not hit the fair lead 4. Therefore, the boom 2 can be lowered to the ground as it is. Therefore, unlike the conventional case, it is not necessary to regulate the descending position of the boom 2 by the limit switch so that the boom 2 and the fair lead 4 do not come into contact with each other during the operation of the drag line. It is not necessary to provide means for lowering the fair lead 4 in order to prevent the boom 2 from hitting the fair lead 4 when descending to the ground.

The positioning means for the frame 10 using the weight 15 of the present invention can be constructed at low cost because of its simple structure.
In addition, a method of positioning with a spring or the like, or a method of fixing the rotation of the frame 10 with a stopper can be considered.

[Effect of device]

As described above, according to the present invention, the weight increasing portion is formed on one sheave side of the rotatable frame, and when the drag rope is not tensioned, the weight increasing portion allows the weight to increase. Since the attitude of the frame is restricted so that the two sheaves are oriented in the vertical direction, the boom does not hit the fair lead when the boom descends. Therefore, the boom can be directly lowered to the ground. As a result, the escape of the lower boom can be reduced, and the structure of the lower boom can be simplified. Further, the life of the drag rope due to bending can be improved by further increasing the sheave diameter of the fair lead.

[Brief description of drawings]

FIG. 1 is a side view of a fair lead showing an embodiment of the present invention, FIG. 2 is an enlarged side view of a part of FIG. 4, FIG. 3 is a plan view of FIG. 2, and FIG. An overall side view of the drag line, FIG. 5 is a plan view corresponding to FIG. 3 in the related art, and FIG.
FIG. 1 is a side view showing a conventional fairlead lowering means. 1 ... crane body, 2 ... boom, 3 ... winch,
4 …… Fairlead, 5 …… Drag line bucket, 6
...... Drag rope, 7 ...... Housing, 10 ...... Frame, 11, 12 ...... Sheave, 13, 14 ...... Roller, 1
5: Weight

Claims (1)

[Scope of utility model registration request] 1. A housing attached to a front part of a mobile crane body, a frame rotatably attached to the housing, two upper and lower sheaves and a pair of left and right rollers rotatably attached to the frame. In the fair lead of the drag line, the drag line attached to the drag line bucket is inserted between the rollers and between the sheaves to prevent irregular winding around the winch for winding the drag line. A weight increasing portion is formed on one sheave side of the frame, and the posture of the frame is regulated by the weight of the weight increasing portion so that the sheave faces in a vertical direction when no tension acts on the drag rope. The fair line of the drag line that is characterized by being.