Patent ID: 6318235
Filing Date: 2001-11-20
Classification: F03C

Abstract:
A selector device for selecting the cylinder capacity of a hydraulic motor having at least two active operating cylinder capacities, the motor comprising at least two main ducts respectively constituting a fluid feed duct and a fluid exhaust duct, the selector device comprising a slide placed in a bore into which at least three communication ports open out, suitable, via distribution ducts of the motor, for establishing selective communication between the main ducts and the cylinders of said motor, a third communication port being designed to be connected to one of the main ducts of the motor, the device having selector means which, in a first stable position of the slide, put a second communication port into communication with the third communication port via a passage between the second and third ports, while isolating said second and third ports from a first communication port, and which in a second stable position of the slide, put the second communication port into communication with the first communication port via a passage between the first and second ports while isolating said first and second ports from the third communication port, the selector means being constituted in such a manner that during displacement of the slide between said stable positions, there exists a temporary situation in which both the passage between the first and second ports and the passage between the second and third ports are open simultaneously;the device comprising means effective, in at least one displacement direction of the slide between its first and second stable positions, to maintain said temporary situation for a time lapse in an intermediate stage during which the section of at least one of the passages constituted by the passage between the first and second ports and by the passage between the second and third ports is constricted.