Abstract: A device for controlling the pressure of the extensible screed of a road paver on the material to be laid down, comprising hydraulic actuators capable of lifting the screed unit and structure for regulating the pressure of the hydraulic fluid without varying the vertical position of said screed, including distributors, non-return valves, maximum pressure valves and, at least one accumulating chamber, wherein an electric circuit for transmitting signals acts upon the hydraulic circuit to adjust the pressure of the fluid in the actuators.

Abstract: A pneumatic suspension device, suitable for transmitting torque, is composed of a single toroid-shaped vibration-damping pneumatic ring. The inner surface of the ring rests on a rim connected to the part of the machine which must be free from vibration (for example, a hydraulic engine). The machine is directly flanged on a reduction unit, and both the machine and device are made integral with a bracket and frame. The outer surface of the pneumatic ring is gripped by a series of S-shaped jaw elements, bolted onto a support ring welded to the inner cylindrical wall of a vibrating drum. The S-shaped jaw elements have a profile such that each pair of jaws, once fixed in position on the outer band of the toroidal pneumatic ring, forms therewith a single body damping the vibration of the drum.