Patent ID: 8079792
Filing Date: 2011-12-20
Classification: B66C

Abstract:
1. A load suspension device that can be adjusted, locked, and braced horizontally, by means of hydraulics, and having an extension device, comprising: two supporting parts that can be moved relative to one another; a hydraulic operating element with two work chambers, said hydraulic operating element being firmly connected with one of the supporting parts and supported in the other supporting part, wherein said hydraulic operating element adjusts the two supporting parts relative to one another by moving; a pressure line; a tank line; an actuating element connected with the two work chambers of the operating element and having two fluid inputs that are firmly connected with the pressure line and the tank line, and two fluid outputs that are each connected with one of the work chambers, and which connect each work chamber with either the pressure line or the tank line, or blocks the outflow of fluid from the respective work chamber; a controller which controls the operation of the actuating element; a measurement sensor disposed on the hydraulic operating element or on the extension device, said sensor detecting a position of the operating element and a position of the two supporting parts relative to one another; and a signaling device that emits a signal to the controller when a given pressure is reached, and wherein the controller thereupon interrupts an inflow of fluid to the operating element or limits the inflow to leakage flow; wherein in order to displace the operating element, the controller sets the actuating element so that the respective work chamber from which fluid is flowing to displace the operating element in a desired direction is connected with the tank line, and the respective work chamber into which fluid is introduced to displace the operating element in the desired direction is connected with the pressure line; wherein the measurement sensor is adapted to transmit a signal to the controller, when or just before a desired position of the hydraulic operating element and the supporting parts relative to one another is reached, and the controller is adapted to set the actuating element so that the actuating element blocks flow of fluid out of the work chamber from which fluid has flowed out during preceding displacement of the extension device, while the other work chamber is still connected with the pressure line, and thus the pressure in both work chambers is increased so that biasing of the operating element and the supporting parts relative to one another takes place; wherein biasing following a biased state of the hydraulic operating element and thus of the extension device is achieved in that as soon as a predetermined bias pressure has been reached in one or both of the work chambers, the signaling device is adapted to emit a signal to the controller, which sets the actuating element so that flow of fluid out of the work chamber that took in fluid during previous displacement of the operating element is blocked, so that fluid to which pressure is applied is contained in both work chambers of the operating element, said fluid being supported in the actuating element connected with each work chamber; and wherein for relaxation of the extension device, the controller is adapted to set the actuating element so that at least one of the work chambers is connected with the tank line.