Movable-arm tower crane

Abstract

The invention provides a movable-arm tower crane which comprises a backward-inclination prevention device, wherein the backward-inclination prevention device comprises a backward-inclination oil cylinder, a travel switch, a limiting detection piece and a hydraulic system; the backward-inclination oil cylinder comprises a rodless cavity; a spring is arranged in the rodless cavity; the travel switch is arranged on the cylinder body of the backward-inclination oil cylinder; the limiting detection piece is arranged on the piston rod of the backward-inclination oil cylinder; when the piston rod moves toward the rodless cavity, and reaches a preset position, the limiting detection piece triggers the travel switch; the hydraulic system comprises an oil tank, an oil drainage pipeline communicatedwith the rodless cavity and the oil tank, a logic cartridge valve which is arranged in parallel to the oil drainage pipeline, and is used for quickly draining oil, an overflow valve for draining the oil under preset pressure, and an electromagnetic valve electrically connected with the travel switch; and the electromagnetic valve is used for controlling the logic cartridge valve to change from anopening state to a closing state when the travel switch is triggered. According to the movable-arm tower crane, due to the backward-inclination prevention device, rigid impact between two members, namely a crane jib and an A-shaped frame, is reduced remarkably; the members are uniformly stressed; and the whole safety is improved.

Description

technical field [0001] The present invention relates to the field of hoisting machinery, more specifically, to a tower crane with a moving arm. Background technique [0002] With the acceleration of my country's economic construction and the dense building complexes, the working space of tower cranes is limited. Based on the development of high-rise buildings, the newly formulated airspace rights licensing system and the disputes caused by cross-occupancy of neighboring territories, people are forced to change the existing traditional concepts and change from trolley luffing to jib pitching, creating benefits for tower crane operations. Space has promoted the transformation and development of various types of boom tower cranes. With the large-scale and intensive development of modern buildings, the construction period requirements are becoming more and more stringent. Therefore, modern building construction is mainly hoisted by large tower cranes. In the past, most high-ris...

AI Technical Summary

Problems solved by technology

[0020] 1. Solve the problem that the rigidity between the boom and the top of the tower or the high rigidity that is easy to produce impact during the anti-backward tilting device of the ultra-large boom tower crane

[0021] 2. Solve the problems of complex manufacturing of the lower support of super-large boom tower cranes, difficulty in ensuring machining accuracy, and inconvenient transportation

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