Patent ID: 6802182
Filing Date: 2004-10-12
Classification: F03C,F04B

Abstract:
A hydraulic circuit including a main fluid circuit which comprises:a hydraulic motor having a preferred operating direction and having a casing which defines an internal space and in which a cylinder block is disposed, and at least two main pipes suitable for being put in communication with the cylinder block of the motor and constituting respectively, in the preferred operating direction of said motor a feed main pipe and a discharge main pipe; the hydraulic circuit further comprising a tapping circuit including means for tapping fluid from the main circuit and means for removing the tapped fluid to a reservoir under atmospheric pressure via a removal pipe; said tapping circuit further comprising a single tapping and removal valve connected continuously via a tapping pipe to a single one of said main pipes, the valve also being connected to the removal pipe, the tapping and removal valve being connected to the discharge main pipe in the preferred operating direction of the motor; the tapping and removal valve comprising: a flow-rate regulator that includes a slide mounted to move in a body, a hydraulic control chamber suitable for being fed with fluid via the tapping pipe to urge the slide to move in a first displacement direction; and resilient return means suitable for urging the slide to move in a second displacement direction opposite from said first displacement direction; wherein one of the elements constituted by the body and by the slide has at least one communication orifice, while the other of said elements has a closure wall suitable for masking said orifice as a function of the position of the slide, a communication passageway between the tapping pipe end the removal pipe being open when said orifice is not masked by said closure wall; and wherein the communication orifice has a length, as measured in the displacement direction of the slide, that is less than the stroke of said slide, said orifice being masked by the closure wall when the slide is in its two end positions so that said communication passageway is opened only when the pressure difference between the tapping pipe and the removal pipe is greater than a threshold value and is less than a limit value.