Hydro-pneumatic braking device

A hydro-pneumatic braking device, comprising at least one friction member mounted adjacent a rotatable component to be braked, a hydraulic operating device mounted adjacent said friction member and operable by a liquid under pressure to urge said friction member into braking engagement with said rotatable component, and pneumatic actuator means for supplying liquid under pressure to said hydraulic operating means, said pneumatic actuator means including a casing mounted adjacent said hydraulic operating device, an elastic bellows mounted within said casing and defining a hydraulic chamber within said bellows, said hydraulic chamber being in fluid communication with the hydraulic operating device, said bellows cooperating with said casing to define another chamber therebetween, a movable wall structure mounted in said casing and extending transversely across said casing and cooperating with the casing to divide a pneumatic section out of said another chamber, means communicating said pneumatic section with a source of gas under pressure, said bellows having a transverse wall in contact engagement with said movable wall to permit movement of said movable wall to contract said bellows when gas under pressure is communicated into said pneumatic section.