JPH0121079B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an overwind prevention device for a crane such as a truck crane.

As shown in FIG. 1, the conventional overwinding prevention device has an overwinding warning switch 4 attached to one end of a bell crank 3 pivotally mounted 2 at the tip of a boom 1, and an overwinding warning switch 4 that is always closed. A weight 6 for opening the switch is suspended from the lower end of the hoisting cable 8, which is loosely fitted through the weight and connects the mounting bracket 7 at the end to the other end of the bell crank 3 in a detachable manner. The hook block 10' is suspended in cooperation with the pulley 9, and when the weight receiver 11 attached to the hook block lifts the weight 6, the overwind warning switch 4 closes and issues an alarm. When changing the number of ropes, it is common practice to remove the mounting bracket 7 from the hoisting rope 8 as shown in FIG. This is because the hoisting cable insertion holes 11a corresponding to each pulley are bored in the horizontal weight receiver 11 to prevent the switch 4 from opening or closing accidentally when the overwinding prevention device is activated. Not only is it really troublesome to change the number of hooks, but the weight receiver 11 is also a pulley 1.
2, so if the hoist block sways in a vertical plane including the pulley support shaft 13 during cargo handling operations, the hoisting cable 8 and the edge of the elongated hole 11a will rub against each other, causing damage to the hoisting cable. There was a simple flaw.

In the present invention, the weight 6 is usually divided into two parts, or it is shaped like a donut through which the mounting bracket 7 is loosely fitted, and the pulley 12 of the hook block 10 is
Focusing on the fact that it is easy to create a gap on the lower side or above the pulley 9 at the tip of the boom to allow the passage of the mounting bracket 7, the number of hooks on the hook block can be reduced while the mounting bracket 7 is attached to the hoisting cable 8. The purpose of the present invention is to provide an over-hoisting prevention device that not only can change the hoisting cable, but also can prevent damage to the hoisting cable during cargo handling operations, and can stably close an over-hoisting alarm switch at a fixed hoisting position of the hoist block relative to the tip of the boom. do.

As the principle of the present invention is shown in FIGS. 3 and 4, the present invention includes a weight 15 suspended and supported by an open cable 5 of an overwind warning switch at the tip of the boom, and a vertical hole 14 of the weight.
Arc-shaped weight receivers 16 and 16', which are substantially adjacent to the outer periphery of the pulley 12 while sandwiching the hoisting cable 8 passing through the The supported hook block 10 is assembled so that the pulley 12 and the center of gravity G of the weight are located on both sides of the hoisting cable 8, and the arcuate weight receivers 16,1 are assembled.
When the lower end of the weight 15 is lifted by the lower end of the weight 15, the inner wall of the shaft above the fulcrum is pressed against the hoisting cable 8 due to the moment of the weight W using the lower end of the weight as the fulcrum B. The present invention is characterized in that the weight is associated with an arcuate weight receiver so that the weight is maintained in a substantially freely suspended posture.

5 to 7 show an embodiment of the present invention, in which the block frame of the hook block 10 is formed by side plates 1 on both sides.
Both ends of the top and both ends of 7 and 17 are connected to the cylinder 18, respectively.
Three intermediate cylinders 20 and bolts 21 are arranged to surround the lower half of the three pulleys 12 so as to be fixed together with bolts 19 and to prevent the hoisting cable 8 from separating from the three pulleys 12. The side plates on both sides are connected and fixed together, and the top plate 22 is welded between the cylinders 18, 18 at both ends of the top. Pulley support shaft 13 between
It is welded concentrically to the pulley support shaft to a plate member 23 fitted to
It is welded and fixed to the top plate 22 via. Further, the arc-shaped weight receiver 16' on the other side is directly welded to one side plate 17 in cooperation with the arc-shaped weight receiver 16 so as to sandwich the hoisting cable 8 having the mounting bracket 7 shown in FIG. 2 attached to its upper end. , the side plate functions as a plate-like member.

The planar oval-shaped weight 15 is divided into two parts along the long axis as shown in Figs. 6 and 4, and is fixed together with two bolts 24, and a vertical hole is formed in the semicircular part of one end. 14, and the lower end of the open cable 5 is connected to a connecting fitting 25 provided directly above the center of gravity G.

In the figure, reference numeral 26 indicates a hook attached to the bottom of the block frame via a universal joint 27, and reference numeral 28 indicates an auxiliary hoisting drum side hoisting cable relief plate welded to the cylinder 20 on both sides of the pulley 12.

As in the case of FIG. 1, the hook block 10 is
A weight 15 is suspended and supported from a pulley 9 at the tip of the boom via a hoisting cable 8, and is suspended and supported approximately horizontally from a switch of an overwind alarm switch 4 via an open cable 5. The throat portion A on the 12 side is approximately in contact with the end portion of the hoisting cable 8 as shown in FIG. 5, or is opposed to the end portion with a gap therebetween.

For this reason, the winding of the hoisting cable 8 by the winding drum becomes overwound, and when the arcuate weight receivers 16, 16' of the hook block 10 push up the lower end of the end of the weight 15 at point B, the A hoisting cable in which the throat portion A above the fulcrum B is constantly tensioned in a straight line by the moment of the dead weight W of the weight with the lower end of the weight end as the fulcrum B, with a tension P based on the dead weight of the hook block 10, etc. 8, the weight can be pushed up while in a substantially freely hanging position, and therefore, the overwind warning switch 4 can be stably and accurately closed at a fixed hoisting position of the hook block.

When the weight 15 is in a freely suspended state, even if there is a gap between the throat portion A and the hoisting cable 8, the arcuate weight receiver 16, 16' does not stop when the weight starts to be pushed up. The inclined surface presses the weight laterally,
Since the weight is lifted after its throat portion A is pressed against the hoisting cable 8, the weight is lifted while always maintaining a substantially freely suspended posture.

In the illustrated embodiment, the semicircular portion of the planar oval-shaped weight 15 on the drilling side of the hole 14 is engaged with the arc-shaped weight receivers 16, 16' on both sides made of round bars because of the winding. This is to keep the plane position of the throat portion A in pressure contact with the upper cord 8 substantially constant at all times.

In addition, when changing the number of hooks, remove the three sets of bolts 21 and the spacer 20 from the hook block 10, and insert the space below the pulley 12 of the hook block through which the end fitting 7 of the hoisting rope 8 can pass. If the hoisting cable 8 and the weight are disengaged by loosening the bolt 24 and opening the hole 14 of the weight 15, the arc-shaped weight receiver and the plate supporting it can be formed. Since the shaped member does not interfere with changing the number of ropes attached to the pulley 12, the end connecting fitting 7 of the hoisting cable removed from the boom tip is passed along the empty space around the pulley 9 at the boom tip, and all pulleys are connected. The cables can be freely changed between a state in which the hoisting cables 8 are hung on the hoisting cables 12 as shown in the figure, and a state in which the hoisting cables 8 are hung on the pulleys 12 at both ends.

The case where the hoisting cable 8 is engaged and disengaged from the vertical hole 14 of the weight when changing the number of ropes between the pulleys 9 and 12 has been described above. The bell crank is configured such that the connecting parts of the alarm switch 4 are located on both sides of the boom tip, and the part of the hoisting cable 8 that does not require changing the line when changing the number of line lines is connected to the vertical hole 14 of the weight. If it is made to penetrate through the hole all the time, it is possible to eliminate the work of engaging and disengaging the hoisting cable 8 to the vertical hole, and the present invention also includes this case.

In addition, in the illustrated embodiment, a vertical hole 14 having a throat portion 14a is bored in the weight 15 eccentrically from the center of gravity G, and the fulcrum B is set so as to stabilize the posture of the lifted weight regardless of the movement of the hook block or the like. This increases the self-weight moment of the weight at the center and prevents damage to the hoisting cable due to relative sliding or oscillation between the hoisting cable and the weight, but the weight is formed in the same donut shape as before. The hole can also be made into a straight hole.

[Brief explanation of drawings]

Fig. 1 is a side view of the conventional device, Fig. 2 is a detailed view of the hoisting cable terminal, Fig. 3 is a longitudinal sectional front view of the main part of the present invention, Fig. 4 is a view taken along the X arrow in Fig. 3, Figures 5 and 6
The figures are a longitudinal sectional front view and a plan view of the hook block portion of the present invention, respectively, and FIG. 7 is a sectional view taken along YY line in FIG. 5. 1... Boom, 3... Bell crank, 4... Overwind alarm switch, 5... Open cable, 6... Weight, 7... Hoisting cable end mounting bracket, 8... Hoisting cable, 9... Pulley, 10, 1
0'...Hook block, 11...Weight holder, 12...
Pulley, 13... Pulley support shaft, 14... Pit, 14a... Throat part, 15... Weight, 16, 16'... Arc-shaped weight receiver, 17... Side plate, 18, 20... Interval, 19, 2
1... Bolt, 22... Top plate, 23... Plate member.

Claims (1)

[Claims] 1. A weight suspended and supported by the open rope of the overwind alarm switch at the tip of the boom, and an arc-shaped weight receiver that is approximately adjacent to the outer periphery of the pulley, sandwiching the hoisting cable that passes through the vertical hole of the weight. The top of the block frame and the hook block supported by the pulley support shaft are assembled via a plate-shaped member parallel to the pulley rotating surface so that the centers of gravity of the pulley and weight are located on both sides of the hoisting cable, and then When the lower end of the weight is lifted by the arc-shaped weight receiver, the moment of the weight's own weight with the lower end of the weight as the fulcrum causes the inner wall of the shaft above the fulcrum to come into pressure contact with the hoisting cable, and the weight is lifted. An overwinding prevention device for a crane, characterized in that an arcuate weight receiver and a weight are associated with each other so as to maintain the weight in a substantially freely suspended posture.