Hoist telescopic hydraulic control system and construction machinery

Abstract

The invention relates to the field of boom extension and retraction control systems and discloses a winch telescopic hydraulic control system and engineering machinery. A main oil pump (2) of the winch telescopic hydraulic control system can be controlled to selectively pump pressure oil to a motor (3) through a first working oil circuit (L1) or a second working oil circuit (L2) to drive a boom toextend or retract; a feedback control oil circuit (L3) is connected with the main oil pump; a proportional on-off valve (6) provided with a first liquid control chamber is arranged on the feedback control oil circuit (L3); a stroke control oil circuit (L4) is connected with the first liquid control chamber; a proportional stroke valve (7) is arranged on the stroke control oil circuit (L4); when the boom extends to a predetermined extension position, the opening of an oil opening of the proportional stroke valve (7) is increased along with the increase in the extension length of the boom, andthe first liquid control chamber is communicated with the first working oil circuit (L1) to control the gradual change of the proportional on-off valve (6) from an on state to an off state. Therefore,the safety during the boom extension is improved.

Description

technical field [0001] The invention relates to a boom telescopic control system, in particular to a winch telescopic hydraulic control system. On this basis, the present invention also relates to a construction machine with the winch telescopic hydraulic control system. Background technique [0002] In construction machinery similar to cranes and fire trucks, it is often used to hoist the frame on the construction machinery to do telescopic movement. But, when hoisting drive frame body stretches out, must control the extending stroke of frame body, in order to avoid frame body to stretch out overtravel and cause frame body to fall off. [0003] In the existing winch drive system, the extension stroke of the frame body is often detected by electrical components, and the extension stroke of the frame body is controlled according to the detection results of the electrical components. However, when the engineering machinery where the frame body is located is powered off or is...

AI Technical Summary

Problems solved by technology

However, when the construction machinery where the frame body is located is powered off or is in a manual operation condition, the extended stroke of the winch drive frame body loses protection immediately.

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