JP4321755B2 - Tower crane jib tilt prevention device - Google Patents

Description

  The present invention relates to a small self-propelled tower crane for housing construction, and more particularly, to a jib tilt prevention device.

  In urban areas, three-story houses are being built for effective use of narrow sites. A small tower crane is required to construct a house. However, the site area and the width of the front road are narrow, and the use of truck cranes may be hindered due to the wires and telephone lines that are installed along the road. If a truck crane is installed on the road, it will block the road and obstruct traffic.

  Even if a truck crane can be put in the site, at least a space for withdrawing the crane must be secured, and the building space is cut accordingly. Therefore, there is a problem that the construction period is prolonged because the construction is abandoned or the truck crane cannot be used.

  A large tower crane for building construction assembles the crane itself in the building space and raises the height of the tower as the building progresses, and it takes time to carry in, assemble, disassemble, and carry out crane parts. Considering the fact that an auxiliary crane is required for disassembly and removal, and that the ceiling of the first floor of the house is 3 m or less, it is difficult to carry out large crane parts such as crane mounts. It cannot be used for general housing construction due to physical conditions.

  In order to solve this problem, a small self-propelled tower crane disclosed in Patent Document 1 has been developed. FIG. 1 is an overall view showing a use state of the self-propelled tower crane disclosed in Patent Document 1. FIG. In the figure, 1 is a self-propelled tower crane. a is a self-propelled cart, and has traveling means m such as a rubber crawler. b is a mast that can be expanded and contracted by hydraulic pressure and can be raised and lowered by a hydraulic cylinder g. c is a revolving frame rotatably attached to the top of the mast b. The jib d is detachably attached for use. The jib d can be disassembled into a plurality of blocks, and each block has a weight that can be carried by hand. e is an outrigger. The jib d is pivotally attached to the rear end of the swivel frame c so as to be raised and lowered.

  f is a floor of the building, k is a through hole provided on the floor f and through which the mast b passes. h is a lifting wire connected to the winch i, and j is a hydraulic cylinder for raising and lowering the jib d.

Patent No. 2928504

In such a self-propelled tower crane 1, when the jib is lifted and winded with a strong wind, a part of the machine may be broken and the jib d may fall backward. It is necessary to attach a tilt prevention device d.

As such a tilt prevention device, there is a device in which both sides near the front end of the swivel frame c and both sides in the middle of the jib d are connected by a rope (not shown), and the rope is stretched at the upper limit of the jib undulation. When the jib descends, the rope loosens and hangs down from the front end of the swivel frame c. Therefore, when the swivel frame turns, the rope may be caught and the machine may be broken.

FIG. 2 shows another example of the jib tilt prevention device. In addition, illustration of the turning frame c is abbreviate | omitted in this figure. In the figure, d is a jib that can be raised and lowered, d1 indicates the lower limit position of the jib d, and d2 indicates the upper limit position of the jib. p is a limit stopper, which is made of a steel pipe and has an H shape in a plan view. The proximal end is pivotally attached to an intermediate position of the jib d, and the distal end is a free end. A spring r is provided as a shock absorber on the base end side of the limit stopper p. q is a stay. Note that r1 indicates a state where the spring r is contracted, and r2 indicates a state where the spring r is extended. Reference numeral s denotes a contact plate, which is provided so as to protrude from the rear end of the revolving frame c.

This anti-tilt device is sturdy and does not get in the way when the swivel frame swivels, but has a problem of high cost because it is sturdy.

The present invention has been devised in view of such problems of the prior art, and provides a tower crane jib tilt prevention device that has a simple structure and is inexpensive, and that does not interfere with the turning of the turning frame. With the goal.

In order to achieve the above object, a tower crane jib tilt prevention device according to the present invention includes a swivel frame pivotally attached to the top of a mast and a jib pivoted pivotally on the rear end of the swivel frame. A crane jib warp prevention device that connects both sides near the front end of the swivel frame and both sides in the middle of the jib so as to cross each other. It consists of a guard that protrudes forward from the front end of the frame and receives a rope that sags from below when the jib descends.

  The width of the guard is preferably wider than the width of the swivel frame, and the overhanging length of the guard is preferably a length that does not interfere with the swivel even if the rope falls from the tip of the guard.

Next, the operation and effect of the present invention will be described. Near the front end of the swivel frame and the middle of the jib are connected with a rope so that the rope is stretched up to the upper limit of the jib's undulations. The safety is improved. Even when the jib is lowered and the rope is slack, the slack rope is caught from the bottom by the guard provided protruding forward from the front end of the swivel frame, so that the slack rope may be caught when the swivel frame turns There is no. Since the rope is stretched so as to cross when viewed from the front, the slack rope does not protrude from the guard, which is slightly wider than the width of the swivel frame. Moreover, the manufacturing cost is much lower than that of the robust anti-tilt device shown in FIG.

An embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a drawing of the tower crane jib tilt prevention device of the present invention, showing a state where the jib is at the upper limit, (A) is a side view, and (B) is a front view. FIG. 4 is a side view showing a state where the jib is at the lower limit in the tilt preventing apparatus. In these drawings, the same reference numerals are given to portions common to those already described in FIGS.

In these figures, b is a mast. c is a turning frame attached to the top of the mast so as to turn by a hydraulic motor. d is a jib, the base end of which is pivotally attached to the rear end of the swivel frame c by a pin c2, and is undulated by a hydraulic cylinder j, and d2 indicates the upper limit position. 3 and 4 are partial assembly views of the vicinity of the turning frame c of the self-propelled tower crane 1 shown in FIG.

4 is a tower crane jib tilt prevention device, which consists of a rope and a guard. 2 is a rope. The rope 2 is composed of two ropes 2a and 2b. The rope 2a connects the right side when viewed from the front near the front end c3 of the swivel frame c and the left side at the required position d3 in the middle of the jib d, and the rope 2b is viewed from the front near the front end c3 of the swivel frame c. The left side and the right side at the required position d3 in the middle of the jib d are connected. Therefore, as shown in FIG. 3B, the rope 2a and the rope 2b cross in the middle. In addition, 2c is a jig | tool which connects the both ends of rope 2a, 2b, the turning frame c, and the jib d with a toggle.

Reference numeral 3 denotes a guard provided so as to protrude forward from the tip of the swivel frame c. The guard 3 is manufactured by processing a steel round bar. 3a is a front leg, 3b is a rear leg, and each has two legs, and the lower end is fixed to the turning frame c. 3c is a groove-shaped lateral member that extends in the left-and-right direction before and after the guard 3, and 4d that extends in the front-rear direction. It is a vertical member, and is formed in an eye shape in a plan view by the horizontal member 3c and the vertical member 3d. The upper ends of the front legs 3a and the rear legs 3b are fixed to the two vertical members 3d in the middle of the four vertical members. 3e is a triangular member extending rearward from the vicinity of both ends of the rear transverse member 3c.

  Next, the operation and effect of the embodiment will be described. The vicinity of the front end c3 of the swivel frame c and the middle d3 of the jib d are connected by the rope 2 so that the rope is tightly stretched at the upper limit d2 of the undulation of the jib d. Even if it is heated, it is pulled by the rope 2 so that the jib d does not fall down and the safety is improved. Even when the jib d is lowered and the rope 2 is slack, the slack rope 2 is received from below by the guard 3 provided to project forward from the front end c3 of the swivel frame c. The rope 2 will not get caught. Since the rope 2 is stretched so as to cross when viewed from the front, the slack rope 2 does not protrude from the guard 3 slightly wider than the width of the swivel frame c. Moreover, the manufacturing cost is much lower than that of the robust anti-tilt device shown in FIG.

  The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the invention.

It is a general view of a self-propelled tower crane. It is drawing of the conventional tower crane jib tilt prevention apparatus. It is drawing of the jib tilt prevention apparatus of the tower crane of this invention, (A) is a side view, (B) is a front view. It is a side view of the jib tilt prevention apparatus of the tower crane of this invention, and has shown the state when a jib exists in a minimum position.

Explanation of symbols

1 Self-propelled tower crane 2 Rope 3 Guard b Mast c Turning frame d Jib

Claims (1)

A tower crane with a telescopic frame that can be extended and retracted on a crawler-type self-propelled stand, a pivot frame that is pivotably attached to the top of the mast, and a jib pivotally pivoted at the rear end of the pivot frame This is a device for preventing the tilting of the jib, which connects the both sides near the front end of the swivel frame and the both sides in the middle of the jib so as to cross each other. It consists of a guard that extends from the front end and extends upward and receives the rope that sags when the jib descends from below, and the guard has a width wider than the swivel frame, and the guard overhang length is Even if the rope hangs down from the tip of the guard, the hanging part of the rope is away from the front end of the turning frame so that it does not interfere with the turning. Jib tilting prevention device of the length tower crane out.

Images