Patent ID: 7434503

Claim:
Pressure regulation device for a hydraulic percussion appliance, comprising a body within which is formed a bore having a plurality of zones of different diameters, in which is mounted a piston having a plurality of zones of different diameters, the bore and the piston delimiting a plurality of chambers connected to the hydraulic circuit, in order, under the action of a distributor, to ensure an alternating movement of the piston which strikes against a tool, wherein two axially offset components are mounted in the bore of the body and concentrically to the piston, between which components a deformable washer is arranged, one of the components being immobile and the other component being mounted slidably in the bore and displaceably in the direction of the immobile component under the action of the hydraulic fluid feed pressure which is exerted on that face of the movable component which faces away from the immobile component, this displacement of the movable component causing a deformation of the elastic washer in order to give rise to a passage of variable cross section on the circuit for the return of the hydraulic fluid towards the reservoir or on a circuit which diverts part of the feed flow of the appliance towards the return circuit, so as to regulate the inlet pressure.