Valve, in particular for extensible towing-eye devices for vehicles, comprising a passage-way with a variable section in the neighbourhood of the sitting

摘要

The valve according to the invention comprises a body (9) in which extends a channel (10) communicating with an inlet orifice (11) and an outlet orifice (12) which can be connected respectively to a hydraulic receiver (2) and to a reservoir (5) forming part of a hydraulic circuit, a seat (13) formed in the wall of the channel (10), between the inlet (11) and outlet (12) orifices, a slide (14) which can move in the channel (10) between a closing position in which it bears against the seat (13) and isolates the inlet (11) and outlet (12) orifices, and an opening position in which it is remote from the seat (13) and establishes a communication between the inlet (11) and outlet (12) orifices, and resilient members (15) for stressing the slide (14) into its closing position. According to the invention, the slide (14) defines, with the wall of the channel (10) which is adjacent to the seat (13), an annular space whose cross-section is smaller at its end adjacent to the said seat than at its other end. This valve is more particularly intended to be fitted in the hydraulic circuit of an extensible towing device for a vehicle.