Abstract: A hydraulic hammer is provided, suitable for use as a crust-breaker of aluminum electrolysis pots, having a hydraulically actuated beating mass reciprocally movable in a cylindr to strike against a tool, an intake duct with a filter and a one way valve for conveying external air into a top chamber defined by the rear face of the beating mass, the inner surface of the cylinder and the upper base of the cylinder during the downward stroke of the beating mass, a connection duct with a one way valve for conveying the filtered air contained in the top chamber into a bottom chamber defined by the front face of the beating mass, the inner surface of the cylinder and the rear face of the tool during the upwards movement of the beating mass, so that an over pressure is created in the bottom chamber to exclude dust, etc., from entering through the clearance between the tool and the guide bushing.

Abstract: An emergency seat belt cutter for mounting in the passenger compartment of a vehicle. The cutter has a handle, a long and narrow blade mounted longitudinally in a blade support portion integral with the handle and lugs on the handle for engagement with a sheath. The sheath has a cylindrical interior with a mounting for the inside of the vehicle, a coil spring in the bottom of the cylindrical interior and bayonet connectors for engagement with the lugs. The cutter is inserted into the sheath with pressure and a counterclockwise rotation. The cutter is removed by again applying transverse pressure and turning in a clockwise direction wherein the coil spring expels the knife into a person's palm.