Grab device and method for operating a grab device

Abstract

The invention relates to a method for operating a grab system, comprising a carrier device and a cable grab arranged thereon, which cable grab comprises a grab frame, which is held by a retaining cable on the carrier device, at least two grab buckets, which are mounted on a lower end of the grab frame, so as to be able to swivel between a closed position and an open position, and an actuating device with an actuating cable for swivelling the grab buckets, wherein an actuating cable is guided from the carrier device to the actuating device, and the carrier device has a driven first cable winch for the retaining cable and a driven second cable winch for the actuating cable, wherein the carrier device has an undercarriage and an upper carriage, which is mounted thereon for rotation about a vertical axis and has a cantilever arm on which the cable grab is vertically adjustably mounted, wherein in a removal step, in order to form a trench in the ground, the cable grab is lowered into the ground by the retaining cable with the grab buckets open, the grab buckets are closed to remove and collect soil material, the cable grab is pulled out of the ground by the retaining cable and swiveled to an emptying position, in which the grab buckets are opened to discharge the collected soil material, by rotating the upper carriage, and then the cable grab is moved back into the ground trench to repeat the removal step. In accordance with the invention, a control device is provided with which a rotation of the upper carriage to the emptying position and an opening and closing of the grab buckets to discharge the soil material or a rotation of the upper carriage from the emptying position back to the ground trench are controlled automatically.