How Many Types Of Spreader Grabs Are There?
Jun 21, 2023
How Many Types of Spreader Grabs are there?
The electric motor grab itself has a closing mechanism, which has various styles. Our company installs a standard electric hoist or hoist on the grab as the opening and closing mechanism.
The motor grab can be seen as moving the closing roll onto the grab itself. Because the motor grab is no longer subject to the upward pulling force of the closing rope like the four-rope grab when it is closed, the self-weight of the grab fully plays the role of digging. Because of its large grabbing capacity, it is most suitable for grabbing ore and other materials.
Single rope hanging grab
The opening and closing of the single-rope grab is mainly due to the cooperation of elastic elements, sliding frames, and locking hooks.
When catching materials, after the opened grab bucket falls on the material, the steel wire rope continues to descend to make the carriage slide down. Due to the action of the spring on the carriage, the claw mouth is on the hook. The driver lifts the carriage to raise the lower beam, and the jaw plate closure.
When unloading, when the full load is sent to the pile or the ground of the unloading site, the steel wire rope continues to descend, causing the carriage to slide down for a certain distance, and the pressure on the claws from the hook mouth immediately loses. Under the action of the pressure spring on the head, the claws Rotate to disengage the hook mouth, the driver lifts up again, and gradually opens the jaw under the action of the lower beam and the self-weight of the material.
Double rope grab
Double rope grab is suitable for all kinds of cranes with double lifting device structure (single rope), mainly used with bridge cranes, port machinery, winches, widely used in ports, power plants, docks, chemical industry, etc. Grab all kinds of loose accumulations, such as ore, coal, slag, etc., for loading, unloading, feeding and other operations. According to the material characteristics, it can be equipped with light, medium, heavy and super heavy. Suitable for grabbing all kinds of loose accumulations.
Scissor grab
The scissor grab is to extend the ends of the two jaws near the hinge point into a rope-type force arm. The two arms share a center hinge point. The opening action of the scissor grab relies on loosening the wire rope of the pulley block at the scissor arm and tightening it. The closing action is accomplished by tightening the steel wire rope of the pulley block, using the principle of leverage to increase the force, so that the jaw plate is closed and grasped boringly, and its closing torque gradually increases with the closing process. When grasping the material, it is clean and leak-free. It is mostly used on large bridge type ship loaders.
Four rope grab
The four-rope grab is composed of a strut, a jaw plate and a beam. The retrieving action of the four-rope grab is controlled by the lifting reel and the opening and closing reel on the crane. The ends of the two wire ropes wound on the lifting reel are fixed on the wedge shell at the head of the grab. The head is hinged, and when the lifting drum rotates, the steel wire rope drives the grab up and down through the wedge shell; the two steel wire ropes wound on the opening and closing drum are wound between the head of the grab and the pulley of the beam through the guide wheel to control the movement of the grab. Opening and closing.
When retrieving materials, the grab bucket is lowered to the material pile in an open state (the opening and closing reel does not move at this time), and the opening and closing reel is started in the lifting direction (the lifting rope does not move), under the action of the grab's own weight, The jaw plate of the grab bucket digs into the material. After the grab bucket is completely closed, start the lifting drum and the opening and closing drum at the same time to lift the full-load grab bucket to a certain height. Close the reel (the lifting reel does not move), and the grab opens to discharge.
