Abstract: The shredding unit comprises a horizontal drum mounted transversely within a cage having a front feed opening. Knives are rigidly fixed on the circumference of the drum which is partially surrounded by an evacuation grid having calibrated holes. In the active or work position, backing knives placed in alignment at each end of the grid and opposite to the drum project inwards from the grid while the knives of the drum pass in the immediate vicinity. Each backing knife is mounted at the extremity of a support plate and is capable of withdrawing under excessive pressure in opposition to a jack which urges the backing knife towards the active position.

Abstract: A hydro or oleopneumatic device comprises a pressure transformer consisting of a single or multiple pneumatic cylinder having one or a number of stages in which the piston is rigidly coupled to an accumulator. The accumulator piston discharges the liquid to a function jack which utilizes the energy produced by the pneumatic pressure. The pneumatic cylinder is not provided with compressed-air exhaust ports and is freely connected to a compressed-air reservoir at the working pressure. The volume VR of the reservoir is large in comparison with the volume VC of the pneumatic cyclinder, the ratio VC/(VR + VC) being equal to the permissible variation in the working pressure of the air according to the intended use of the device.