Patent ID: 6948580
Filing Date: 2005-09-27
Classification: B62D

Abstract:
1. A hydraulic tilting device for tilting a cab of a vehicle between a driving position and a tilted position, which cab in the driving position is resiliently supported on a chassis of the vehicle, which tilting device comprises: a reservoir for hydraulic fluid, a pump connected to the reservoir and having a delivery port for delivering hydraulic fluid under pressure; a double-acting, hydraulic tilting cylinder, for tilting the cab, comprising a cylinder housing, containing a cylinder space, and comprising a piston/piston rod assembly including a piston and a piston rod, which piston/piston rod assembly is moveable back and forth in said cylinder space, the piston rod of which assembly projects outwards out of the cylinder housing through a corresponding piston rod seal, which piston/piston rod assembly forms a pull chamber in the cylinder space, so that the piston/piston rod assembly is retracted when hydraulic fluid is supplied to said pull chamber, and a push chamber, so that the piston/piston rod assembly is extended when hydraulic fluid is supplied to said push chamber, a corresponding pull connection and push connection being provided for the pull chamber and the push chamber, in which the tilting cylinder is further provided with a lost-motion conduit, extending between ports which open into the cylinder space of the tilting cylinder, which ports are in communication with the push chamber and the pull chamber respectively if the piston of the piston/piston rod assembly is in a lost-motion range defined by the ports, the piston/piston rod assembly being able to move within said lost-motion range if the cab is carrying out spring movements in its driving position, a valve, which is disposed in the lost-motion conduit and can shut off the lost-motion conduit, a line system, such that the pull connection and the push connection are connectable to the delivery port of the pump or the reservoir, wherein the tilting device is designed such that during movements of the piston of the piston/piston rod assembly within the lost-motion range hydraulic fluid is supplied from the reservoir to the pull chamber by way of the pull connection, and wherein hydraulic fluid is moved from the pull chamber to the reservoir by way of the lost-motion conduit, so that in general a circulation of hydraulic fluid occurs if the cab is carrying out spring movements.