Abstract: A steam engine with improved intake and exhaust flow provided by separate pairs of intake and exhaust ports located at both ends of a steam drive cylinder. A slide valve located adjacent to the drive cylinder provides for timed sealing of intake and exhaust ports during operation. Exhaust is facilitated by the provision of two paths of exhaust from the cylinder and the exhaust ports may be adjusted for a flow volume to meter exhaust steam flow to significantly reduce back pressure only at low speeds of said engine.

Abstract: A hydraulically operated percussion hammer comprising a percussion piston that reciprocates by means of the pressure of the pressure fluid, a main valve that is controlled by the position of the percussion piston and that guides the pressure fluid to the percussion piston in order to provide a reciprocating motion, and a pressure control valve that is placed in an outlet duct for pressure fluid and that prevents the flow of the pressure fluid from the percussion apparatus before the pressure of the pressure fluid in the inlet duct exceeds the set value of the pressure control valve. The percussion apparatus comprises a separate by-pass duct which allows the pressure fluid to flow from the pressure chamber of the percussion piston past the pressure control valve to the outlet duct until the percussion piston has reached a certain point during its return motion.

Abstract: Hydraulic hammers are normally controlled by an actuating valve which controls the flow of fluid from a source of pressurized fluid to the hydraulic hammer. During certain periods of operation, the actuating valve totally blocks communication of fluid to the hydraulic hammer, thereby causing the fluid from the source of pressurized fluid to be expelled through a relief valve. The subject hydraulic hammer and control arrangement therefor includes an accumulator for storing the pressurized fluid from the source of pressurized fluid during periods of fluid blockage by the actuating valve and for supplementing the flow of fluid from the source of pressurized fluid when the actuating valve is communicating pressurized fluid to the hydraulic hammer. This increases the overall efficiency thereof.

Abstract: The working piston (15) in the cylinder (1) is acted upon by pressure fluid only on one side, while the return movement of the piston is produced by reaction forces (R). The pressure fluid feed and the pressure fluid discharge are effected by way of separate conduits (9, 10) so that there is a continuous interchange of pressure fluid in the cylinder (1). When the maximum piston stroke position is reached, pressure fluid can flow out of the cylinder (1), irrespective of the control position of the control device (2). In both limit positions of the piston (15), the movement of the piston is braked by a mechanical damping means (18).

Abstract: The present invention relates to a sound-dampened driving apparatus for fasteners wherein a main valve member is arranged above a working cylinder of the apparatus and movable within a cylindrical bore. When the main valve member is in its lower at rest position, the main valve member separates the working cylinder from a source of compressed air and connects the cylinder to the atmosphere. When the main valve member is in its upper actuating position, the working cylinder is connected to the source of compressed air and the valve member blocks the cylinder connection to the atmosphere. The space above the main valve member within the cylindrical bore is capable of being alternately connected to either the atmosphere or compressed air, and includes a sound dampening means arranged in the space above the main valve member.

Abstract: An oscillator actuated hydraulic impulse of the type including a spool valve actuated by an alternating signal from an oscillator to switch the hydraulic pressure in a double acting cylinder in order to cause reciprocating motion of a piston which strikes a boring tool. The hydraulic impulse device further includes a means for controlling the transition from the impulse stroke to the return stroke of the piston. In some embodiments, the hydraulic impulse device may further include a means for varying the duration of the impulse stroke and the return stroke of the piston.

Abstract: A hydraulically operated vibration exciter for a vibrating compactor of the kind comprising a piston in a cylinder, the piston and cylinder being arranged to move to and fro relative to each other, a source of liquid under pressure, a pressure line connecting the source to the cylinder and means for causing the liquid to move to and fro between the source and the cylinder to bring about the relative movement between the piston and cylinder is cooled by a method in which, during the relative movement, a quantity of the liquid is withdrawn from the cylinder and this quantity is not returned to the cylinder in the subsequent stroke, but is replaced by a fresh quantity of liquid at a lower temperature.

Abstract: A vapor engine including a cylinder in which a piston reciprocates and having an inlet valve in the cylinder head which is driven from its seat by the piston as it approaches the cylinder head. The time at which the valve is driven from its seat does not change relative to the top dead center position of the piston. The travel of the valve body is ballistic and the valve remains open for a time determined by a combination of the piston velocity at the initial contact, the distance the valve travels before hitting a stop from which it rebounds elastically toward its seat, the pressure drop across the valve and the mass of the valve. The exhaust valve of the engine may be either internal and actuated by mechanical forces or external, in which case it is actuated by pressure forces. In one embodiment of the invention the stop from which the valve rebounds may be adjustably positioned manually or automatically to control the period of time during which the intake valve is open.

Abstract: A power tool having a cylindrical housing accomodating a hammer and a two-step defining piston head, with central, rear and supplementary chambers in the housing, said head and supplementary chambers being constantly intercommunicated through a passage provided in the housing. The design of the power tool is aimed at minimizing vibrations of the housing and reduction of the forces applied to the handle during normal operation of the power tool.