Abstract: A pneumatic control valve for a fully pneumatic system for controlling both the low pressure and working pressure sides of a pneumatic installation. The valve mechanism is designed to increase the switching frequency of the mechanism.

Abstract: A coupling for connecting a supply conduit to a rigid or flexible extension tube, designed to carry a fluid under pressure, comprises a cylindrical housing having one end wall fastened to the conduit and another end wall formed with an opening for the insertion of an extremity of the tube. The inserted tube extremity is closely surrounded, within the housing, by one or more dished springs which can be deformed under axial pressure from an adjoining annular thrust member when the tube is filled with fluid; the pressure of the fluid may act upon the thrust member through an elastic ring, embracing the tube extremity which shifts relatively to the housing under such pressure, or directly through a gap behind that member which then operates as a piston forming a socket for the tube.