Abstract: Pressure-generating device for braking circuits of motor vehicles of the type having electric motors for controlling a device for generating braking pressure. Electric motors (15), associated with each wheel (1, 1', 2, 2') or pair of wheels (1,1'-2,2') of the same axle, drive positive displacement pumps (16) generating the braking pressure for cylinders (7) of brakes (3 to 6).

Abstract: A device for accelerating the initial stroke of hydraulic jacks, comprising a cylinder, a piston provided with sealing-rings, said cylinder fluid feed-orifices and orifices for exhausting fluid through a plurality of calibrated ports arranged in rows in the cylinder periphery at both ends thereof, characterized in that at least one piston-ring (S.sub.2, S.sub.4) at one end of piston (P) is mounted in its respective groove (R.sub.1) with a certain amount of axial and lateral clearance, said groove communicating with the bottom of the piston through at least one port (B.sub.1).