Abstract: A valve system for starting/restarting an oscillating controller of the type that uses a source of pressurized gas to provide controlled pulses of the pressurized gas to a pump, such as a chemical injector pump. The start/restart valve includes a valve element that is closed by a valve spring when the pressure of the pressurized gas source drops below a predetermined minimum and is opened upon the pressure increasing to a second predetermined pressure higher than the predetermined minimum pressure to thereby provide a higher pressure for starting or restarting the oscillating movement of the controller. The start/restart valve includes a detent mechanism for maintaining the valve element in either the open or closed position until the gas pressure reaches the appropriate pressure level for switching to the opposite position. The opening of the valve element may be caused by the gas pressure being applied directly to the valve element or indirectly through a diaphragm in alternate embodiments.

Abstract: A device for distributing oil under pressure including a head (2) within which, inside a chamber (24), a shuttle (5) slides provided with a shank (5a) sealingly sliding within an end cap (6) and on whose head surface (19) oil at the feed pressure acts coming from a switch duct (18). The head (2) is provided with a feed hole (8) connected to the chamber (24) and is closed at the other end by a shutter (7) connected to a drain hole (9), while the shuttle (5) is provided with an inner cavity (26) and end ducts (25) and it is shaped so as to have in the chamber (24) opposite transverse surfaces (22, 23) whose difference of area in favour of the surface (23) at the end where the shank (5a) is located is smaller than the area of the head (19) of the latter. A hydraulic hammer including the device is provided with a pair of outflow orifices (17, 20) located so that the first orifice (17) is uncovered by the ram (4) at the end of the return travel and the second orifice (20) at the end of the descending travel.

Abstract: A variable frequency control for a hydraulic percussion actuator includes a piston bore and a valve bore. A piston is axially disposed within the piston bore, while a valve is axially disposed within the valve bore. A first piston biasing member biases the piston in a first direction while a second piston biasing member, which overcomes the bias of the first piston biasing member to move the piston in a second direction. A first valve biasing pin biases the valve in a third direction while a second valve biasing pin overcomes the bias of the first valve biasing pin to move the valve in a fourth direction. A hydraulic valve actuator displaces the second valve biasing pin when the piston is extended in the second direction, and a piston actuator activates the second piston biasing pin when the valve is extended in the fourth direction. A valve response member controls the time required for the valve to be displaced in said fourth direction upon actuation of said valve actuating member.

Abstract: A reciprocating piston fluid powered motor having fluid inlet and outlet, wherein reciprocation is controlled by a reciprocable valve spool communicating with said fluid inlet and outlet and cooperating with a valve slide shiftable on said valve spool to control reciprocation of said valve spool. A needle valve assembly controls the exhaust rate proportionally to the operative speed of the motor.

Abstract: An impact tool is described which is capable of developing percussive forces for rock drilling, pile driving, seismic exploration and other repetitive high force applications. The tool contains a hammer and a valve which may be hydraulically actuated so as to oscillate; repetitively executing forward and return strokes during each cycle of oscillation. The valve is actuated in the forward stroke direction by being engaged by the hammer, and in the return stroke direction by fluid pressure means so as to switch the pressure in a cavity in which both the valve and the hammer are disposed for developing forces on the hammer so as to sustain its oscillation. A fluid filled pocket is provided into which the valve enters as it moves in the forward stroke direction, after having switched the pressure in the cavity. A passage is provided on the hammer which is dimensioned so that fluid in the cavity is either connected to a channel, the cavity, or entrapped in the pocket, depending on the position of the hammer.

Abstract: Automatically Self-Reciprocating sequencing valve for use with pneumatic power cylinders/actuators in systems operated at frequencies of a few cycles to a few thousand cycles per minute comprises a valve housing with a central bore adaptable to receive a shuttle member that makes or breaks fluid communication between a fluid supply source and a receiver such as a power cylinder or an actuator of a positive displacement pump in response to fluid pressures acting over surfaces such shuttle member entails as controlled by appropriate slave valve housed alongside therein including fluid supply and exhaust ports entering and leaving said valve housing, and together with said slave valve allowing an automatic reciprocating-valve-operation for as long as the pressurized fluid is supplied thereto to result in self-reciprocating operator responsive to not only system pressures for cycle regulation but also to an externally provided biasing flow regulator for an easy control of cycle frequencies within the desired prac

Abstract: A hydraulic percussion tool for developing repeated impact blows for rock drilling and other high force applications is characterized by a piston hammer reciprocably disposed in a cylinder bore and a tubular valve member coaxial with and actuated by the hammer for controlling the flow of pressurized hydraulic fluid to and from portions of the cylinder bore. The valve member is actuated by the hammer on the return stroke thereof through a column of fluid trapped in an annular chamber formed between a transverse surface on the hammer and an end face of the valve member. Valving mechanism is operable to effect controlled venting of the trapped fluid from the annular chamber to change the position of the valve member with respect to the hammer and thereby control the hammer stroke length, impact blow, and blow frequency.