The opening direction of the grab bucket has two parallel and vertical main beams. The following figure shows the opening of the straight main beam. The fetching device is a four-rope grab bucket with double drum, which is simple in structure and reliable in operation. The grab can be opened and closed at any height. Grab bucket is only suitable for the natural accumulation of bulk materials, when grabbing underwater materials or special materials must be specially proposed when ordering the crane can be used indoors or outdoors, outdoor use to increase the rain cover device