Mast automatic raising and lowering control method and crane using the same method

Abstract

The invention discloses a control method for automatic lifting of a mast. The method is applied to a crane. The crane comprises a mast, a jacking bracket, a jacking cylinder, a rotary table, a movablepulley block, a fixed pulley block, a luffing wire rope and a luffing mechanism, wherein the luffing mechanism comprises a reel, a speed reducer and a motor, and further comprises an angle sensor arranged on the mast and used for measuring the rotation angle of the mast and a tension sensor arranged on the fixed pulley block and used for detecting the tension of the luffing wire rope. According to the method, the angle sensor and the tension sensor are used for detecting the rotation speed of the mast and the tension of the luffing wire rope, and the following speed of the motor is adjusted accordingly. The invention also discloses a crane using the method. The control method for automatic lifting of the mast and the crane using the method can synchronously control the stretching speed ofthe jacking cylinder and the rope-reeling / unreeling speed of a luffing winch, can solve problems in cylinder speed and sudden pressure change during switching of multi-stage cylinders, and are simplein control structure and low in control cost.

Description

technical field [0001] The invention relates to the technical field of mobile cranes, in particular to a mast automatic lifting control method and a crane using the method. Background technique [0002] Mobile cranes usually use a jib for hoisting operations. The jib is connected to the mast through the jib pull plate, and the mast is connected to the luffing wire rope, which is used to convert the retracting motion of the luffing wire rope into the pitching motion of the jib. When the crane is self-disassembling and connecting with the jib pull plate, it is necessary to lift the mast to the front of the crane. Usually, the jacking cylinder is used to realize the jacking of the mast. Cylinders provide thrust and support to the mast. During the lifting process of the mast, the luffing wire rope wound between the head of the mast and the fixed pulley block at the tail of the crane turret is retracted and unwound through the luffing winch along with the lifting of the mast. D...

AI Technical Summary

Problems solved by technology

[0006] In the above-mentioned first method, due to the need to set a secondary pressure valve group to control the overflow pressure, the system structure is complicated, and at the same time, the design margin of the oil cylinder and the mast is required to be increased, which will increase the cost and the weight of the unit; the above-mentioned first method In the two methods, since it is necessary to additionally set up a pressure control valve group and a throttling control valve group to realize the throttling control and pressure control for adjusting the speed of the jacking cylinder and the main luffing winch, the system structure will also be affected. More complex, cost and unit weight increase

[0007] Therefore, how to reasonably control the telescoping speed of the jacking cylinder and the speed of the luffing winch to solve the problem of sudden changes in the speed and pressure of the cylinder when switching between multi-stage cylinders, while ensuring a simple structure of the control system and low control costs, has become an important issue in this field. Technical problems that technical personnel in the field need to solve urgently

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