Height limit detection structure

Abstract

The invention discloses a height limit detecting structure. The height limit detecting structure comprises a differential gear box and a cam limit structure, wherein the first input shaft of the differential gear box is connected with a first hoisting winding drum, the second input shaft of the differential gear box is connected with a second hoisting winding drum, the turn rotation quantity of the first input shaft and the second input shaft is positive, and the counterturn rotation quantity of the first input shaft and the second input shaft is negative; the cam limit structure is connected with the output shaft of the differential gear box; when a grab bucket ascends or descends, the absolute difference of the rotation quantity sum of the first input shaft and the second input shaft is larger than zero, the output shaft rotates under the action of the first input shaft and the second input shaft, and the cam limit structure transmits a detecting signal when the grab bucket ascends to a preset position; when the grab bucket does not ascend or descend, the absolute difference of the rotation quantity sum of the first input shaft and the second input shaft is equal to zero, the output shaft does not rotate, and the cam limit structure does not detect.

Description

technical field [0001] The invention relates to a height detection device, in particular to a height limit detection structure of a grab bucket of a ship unloader. Background technique [0002] At present, hoisting mechanisms are widely used, such as being used in tower cranes to grab materials or building components, or used in ship unloaders for loading and unloading containers or goods. Usually, the hoisting mechanism mainly includes a hoisting drive motor, a hoisting drum, a hoisting wire rope, a rope-winding pulley block, a trolley and a spreader. [0003] For example, Chinese patent document CN2240761Y discloses a four-roller grab control system, which includes a hoisting mechanism for lifting and lowering the grab and an opening and closing mechanism for opening and closing the grab, the hoisting mechanism includes respectively The first and second reels driven by the motor and the hoisting wire rope fixed on the grab bucket and the first and second reels; the openin...

AI Technical Summary

Problems solved by technology

[0004] In this patent document, when the grab bucket needs to be lifted, the first reel, the second reel, the third reel, and the fourth reel are released or retracted at the same time. Yes, but when the hoisting trolley needs to walk, the first reel and the third reel pay out / take in the rope, and the second reel and the fourth reel take in / out the rope Therefore, it can be seen that the hoisting wire rope is not only used for hoisting the grab bucket, but also for the walking of the hoisting trolley; The height of the hook is detected and limited to prevent the lifting hook from rising beyond the limit position, and the height limiter detects the amount of rope output from the lifting drum. According to the amount of rope output from the lifting drum and the known lifting The height of the lifting hook is calculated by parameters such as wire rope magnification; therefore, when the height limiter in the prior art is used for detection, the calculated rope output of the lifting drum includes two parts: The lifting part of the grab bucket and the part used for trolley walking; the existing technology cannot distinguish the amount of rope output from these two parts, so the height limiter in the prior art is used for the four drums described in the control system. It is not correct to detect and limit the height of the grab bucket in the structure, that is to say, the height detector in the prior art cannot be used to detect those that are provided with lifting drums that can both lift the grab bucket and run the trolley. In multi-reel mechanism

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