Backwards-tilting prevention hydraulic control system of arm support and tower crane

Abstract

The invention discloses a backwards-tilting prevention hydraulic control system of an arm support and a tower crane. The backwards-tilting prevention hydraulic control system comprises a buffer oil cylinder (6), a low-pressure energy accumulator (3) and a sensing control device, wherein a flow control valve group (1), a pressure control valve group (2) and a safety valve (4) are connected in parallel between the rodless cavity of the buffer oil cylinder and the low-pressure energy accumulator; the sensing control device is used for controlling hydraulic oil in the rodless cavity to selectively flow through one of the flow control valve group, the pressure control valve group and the safety valve and to finally flow to the low-pressure energy accumulator; when the hydraulic oil flowing to the low-pressure energy accumulator flows through the flow control valve group, the size of a buffering force generated in the buffer oil cylinder is in positive correlation with that of the flow of the hydraulic oil flowing through the flow control valve group; when the hydraulic oil flowing to the low-pressure energy accumulator flows through the pressure control valve group, the buffering force is basically constant. The backwards-tilting prevention hydraulic control system has no oil pump and oil tank, is simple, saves energy, and has the advantages of saving energy in changing amplitudes and generating a basically constant buffering force in a sudden condition of tilting backwards.

Description

technical field [0001] The invention relates to the field of hydraulic control of tower cranes, in particular to an anti-backward hydraulic control system of a jib of a tower crane. Background technique [0002] The luffing jib tower crane completes the luffing operation through the pitching and swinging of the jib, and its luffing system generally uses steel wire ropes, flexible cables or pull plates to bear the luffing tension. When the boom is suddenly unloaded, due to the elastic recovery effect of the flexible cable, if the luffing jib tower crane does not have a reliable anti-tilt device, it is very easy to cause the boom to tilt backward, resulting in a safety accident. Therefore, tower cranes are generally equipped with anti-backward devices or systems. Commonly used ones include spring buffer devices and hydraulic buffer systems. broadly used. [0003] The common hydraulic buffer system for anti-tilting of the jib includes an oil pump, valve block, buffer oil cyli...

AI Technical Summary

Problems solved by technology

[0003] The common hydraulic buffer system for anti-tilt boom includes oil pump, valve block, buffer oil cylinder, etc. The oil pump works for a long time during the working process, resulting in a large waste of energy and the system is complicated

In some hydraulic buffer systems, no oil pump is used, and a return spring is installed in the buffer cylinder. During the return stroke, due to the action of the spring force, a negative pressure is generated in the oil cylinder, which makes it easy to introduce air at the same time when sucking oil from the oil tank. Cause hydraulic oil gas pollution, increase the gas content of the oil, greatly reduce the bulk elastic modulus of the oil, and affect the buffer stroke and buffer force

In addition, during the luffing process of the tower crane, since the hydraulic buffer system with constant force buffering will exert a buffer force on the jib, the luffing mechanism needs to overcome the buffer force to do work, which also causes considerable energy waste

Moreover, the long-term large buffer force acts on the boom, which can damage the boom structure, which is a risk factor for destroying the stability of the structure.

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