Patent ID: 6926372

Claim:
Drive apparatus with a hydraulic motor having a cubic capacity selector suitable for being moved between a first position corresponding to a large active operating cubic capacity and a second position corresponding to a small active operating cubic capacity, the apparatus comprising control means for controlling the selector, which means comprise a hydraulic control chamber suitable for being fed with fluid under pressure via a control duct for the purpose of urging the cubic capacity selector to move to its second position against the force exerted by first return means, the apparatus further comprising a brake system for braking the hydraulic motor, which brake system comprises brake means mounted to move between a braking position and a brake release position, and a brake release chamber suitable for being fed with fluid under pressure via a brake release duct for the purpose of urging said brake means towards their brake release position against the force exerted by second return means, the control duct being suitable for being connected to the brake release chamber for the purpose of putting said brake release chamber into communication with the control chamber, and in the first return means being suitable for returning the cubic capacity selector to its large cubic capacity first position when, while the control chamber is communicating with the brake release chamber via the control duct, the pressure in said brake release chamber becomes lower than a first threshold pressure, whereas the second return means are suitable for returning the brake means to their braking position when the pressure in the brake release chamber becomes lower than a second threshold pressure which is lower than said first threshold pressure.