Abstract: Provided is a hydraulic striking device in which a reverse operation circuit and a forward operation circuit can switch connection states to a high pressure circuit and a low pressure circuit by means of an operation switching valve. Further, the hydraulic striking device is configured to be selectable between a reverse operation mode or a forward operation mode by operating the operation switching valve. A high/low pressure switching portion is provided with a shortening portion for reducing the time required for high/low pressure switching operation in piston front and rear chambers in association with retraction of a valve to be shorter than the time required for high/low pressure switching operation in the piston front and rear chambers in association with advancement of the valve.

Abstract: An impact-driven tool includes a cylinder and a piston slidably inserted into the cylinder and has a large-diameter portion. The cylinder includes: a chamber on one end side; a chamber on the other end side; a communication path that allows the chamber on one end side and the chamber on the other end side to communicate with each other; and a valve chamber that is continuous with one end side in the axial direction of the communication path, and a valve body for piston lifting control that is incorporated so as to be movable up and down and is provided in the valve chamber.

Abstract: A percussion apparatus driven by a pressurized incompressible fluid includes a body with two coaxial bores for slidably mounting of a tool, and separately slidably mounting a striking piston having a stepped configuration. A control device varies a stroke of the striking piston between a long and a short stroke, and is connected to the directional flow valve and to a bottom chamber of the piston cylinder. The control device includes a cylinder in which a spool is mounted. A first face of the spool is situated in a first chamber permanently subjected to a determined pressure, and a second face of the spool is situated in a second chamber connected to the braking chamber for controlling the varying of the stroke of the striking piston.

Abstract: A percussive device and method having, inside a machine housing (3), a reciprocally moveable percussive piston (2), the movement of which is controlled by a control valve (5), which is arranged to alternatively connect a chamber to a pressure source and to low pressure in dependence on a signal corresponding to the axial position of the percussive piston, and a valve (16) arranged to allow adjustment of the axial position of the percussive piston at which the signal is transmitted, by opening and blocking of a connection between one or more control channels (10, 11, 12, 13) and the control valve.

Abstract: This invention relates to a feedback control device for controlling the stroke of an actuator stroke driven by a working fluid. The feedback control device for controlling the stroke correctly controls the stroke using a simple means by compensating secular changes in the flow rate control valve that controls the working fluid. The device for controlling the stroke of an actuator 110 is provided with a single flow rate control valve 1 for controlling the feed and discharge of the working fluid, and the flow rate control valve is operated to control the stroke by feedback. The flow rate control valve 1 has a neutral position where the working fluid is neither fed nor discharged, and a flow rate control valve control device 9 is provided with a learning device 91 for learning variations in the neutral position. The feedback control is executed, i.e.

Abstract: A heart pump has a pump chamber and a pump element that strokes between a retracted and an extended position. A motor rotates a drive shaft in a single direction. A reversing mechanism coupled between the drive shaft of the motor and the pump element converts rotary motion of the drive shaft to reciprocal stroking movement of the pump element. A mechanical stroke length controller connected to the reversing mechanism varies the stroke length in response to changes in fluid pressure in the pump chamber.

Abstract: A metering device of the type in which a shuttle moves axially within a chamber between two terminal positions, with the chamber having fluid inlet and outlet at each end so that fluid may enter through one end to move the shuttle to cause fluid to be ejected through the other end, and vice versa. A control valve is provided to control the fluid flow, the control valve being a spool valve having a spool sealingly slidable within a bore, the spool valve being associated with a device to drive the spool between two alternate positions in response to the shuttle reaching each end of the chamber.

Abstract: A gas driven oscillator (10) comprising an engine (11) having a cylinder (12) and a pair of expansion chambers (13, 14) on either side of a floating piston (15) adapted to reciprocate within the cylinder (12). The piston (15) is mounted on a piston rod (16) extending through the cylinder (12) and into a compressor (17). Compressed air is delivered from a tank (20) to the engine (11) via a pair of valves (22, 23) mounted on an adjustment screw and slidably disposed on the piston rod (16). The spacing between the valves (22, 23) can be adjusted in order to vary the amplitude of the piston (15) within the cylinder (12). The piston rod (16) includes spaced slots (24, 25) which alternate align with passages inside the respective valves (22, 23) to deliver a pulse of compressed air to the respective chambers (13, 14) of the cylinder (12). Mercury is added to or discharged from a tank (42) which is rigidly secured to piston rod (16) to vary the inertia of the oscillator (10).

Abstract: A gas driven oscillator (10) comprising an engine (11) having a cylinder (12) and a pair of expansion chambers (13, 14) on either side of a floating piston (15) adapted to reciprocate within the cylinder (12). The piston (15) is mounted on a piston rod (16) extending through the cylinder (12) and into a compressor (17). Compressed air is delivered from a tank (20) to the engine (11) via a pair of valves (22, 23) mounted on an adjustment screw and slidably disposed on the piston rod (16). The spacing between the valves (22, 23) can be adjusted in order to vary the amplitude of the piston (15) within the cylinder (12). The piston rod (16) includes spaced slots (24, 25) which alternate align with passages inside the respective valves (22, 23) to deliver a pulse of compressed air to the respective chambers (13, 14) of the cylinder (12). Mercury is added to or discharged from a tank (42) which is rigidly secured to piston rod (16) to vary the inertia of the oscillator (10).

Abstract: A gas driven oscillator (10) comprising an engine (11) having a cylinder (12) and a pair of expansion chambers (13, 14) on either side of a floating piston (15) adapted to reciprocate within the cylinder (12). The piston (15) is mounted on a piston rod (16) extending through the cylinder (12) and into a compressor (17). Compressed air is delivered from a tank (20) to the engine (11) via a pair of valves (22, 23) mounted on an adjustment screw and slidably disposed on the piston rod (16). The spacing between the valves (22, 23) can be adjusted in order to vary the amplitude of the piston (15) within the cylinder (12). The piston rod (16) includes spaced slots (24, 25) which alternate align with passages inside the respective valves (22, 23) to deliver a pulse of compressed air to the respective chambers (13, 14) of the cylinder (12). Mercury is added to or discharged from a tank (42) which is rigidly secured to piston rod (16) to vary the inertia of the oscillator (10).

Abstract: A gas driven oscillator (10) comprising an engine (11) having a cylinder (12) and a pair of expansion chambers (13, 14) on either side of a floating piston (15) adapted to reciprocate within the cylinder (12). The piston (15) is mounted on a piston rod (16) extending through the cylinder (12) and into a compressor (17). Compressed air is delivered from a tank (20) to the engine (11) via a pair of valves (22, 23) mounted on an adjustment screw and slidably disposed on the piston rod (16). The spacing between the valves (22, 23) can be adjusted in order to vary the amplitude of the piston (15) within the cylinder (12). The piston rod (16) includes spaced slots (24, 25) which alternate align with passages inside the respective valves (22, 23) to deliver a pulse of compressed air to the respective chambers (13, 14) of the cylinder (12). Mercury is added to or discharged from a tank (42) which is rigidly secured to piston rod (16) to vary the inertia of the oscillator (10).

Abstract: Method and apparatus for controlling a percussive machine by determining, during the phase of rebound of a piston following impact, the existence of an instantaneous flow rate of fluid flowing from a top chamber toward the high-pressure fluid feed circuit. The instantaneous flow rate is determined on the basis of the differential pressure between the top chamber and the high pressure fluid feed circuit. If a flow rate is detected, a control device is fed with pressurized fluid so as to shift a selector piston in a direction for lengthening the stroke of the striking piston.

Abstract: An in-line hydraulic dashpot is disclosed that effectively decelerates the iston of a power cylinder by controllably choking off the oil which is providing pressure to the piston. The in-line hydraulic dashpot of the invention includes a valve spool member movable between an open and closed position along a fluid flow path that supplies oil to the power cylinder. An actuator rod is cooperative with the valve spool member and the piston shaft of the power cylinder to move the valve spool member between its open and closed positions. The in-line hydraulic dashpot eliminates the clashing of mechanical parts and therewith eliminates the noise that would otherwise be generated thereby. The in-line hydraulic dashpot of the present invention makes possible the adaptation of a fixed stroke power cylinder to applications that call for a variable stroke length.

Abstract: An intensifier for delivering ultra high pressure water to a cutting head of a water jet cutting apparatus. The intensifier has a power piston and cylinder assembly connected to piston members extended into pumping chambers in housing located at opposite ends of the piston and cylinder assembly. Inlet poppet valves located in the pumping chambers control the flow of water from inlet passages into the pumping chambers. Outlet poppet valves allow ultra high pressure water to be pumped out of the pumping chamber into an accumulator fluidly connected to the cutting head. Hydraulic fluid under pressure is sequentially directed to opposite ends of the piston and cylinder assembly with a solenoid operated reversing valve. Limit switches operable in response to movement of the piston members control the reversing valve. Linear motion transfer mechanisms are moved with ramps on the piston members to actuate the limit switches to control the reciprocating action of the piston and cylinder assembly.

Abstract: A vibration cancellation device is provided for an air motor with a reciprocating drive piston. The device consists of an anti-phase piston which is axially aligned with the drive piston and reciprocates in the opposite direction of the drive piston. In one embodiment, the stroke of the anti-phase piston is adjustable to permit optimizing its vibration cancellation characteristics.

Abstract: In the hydraulic breaker according to the present invention, oil pressure at a fixed value always flows in the circuit at a low pressure side whenever the piston is raised or lowered, to prevent the need for an accumulator in the circuit at the low pressure side. At the same time, a high pressure oil is required during the raising and lowering of the piston, bringing about less of a change in the surge pressure, attributing to the fact that there is no need for an accumulator in the circuit at the high pressure side. Moreover, the hydraulic breaker of the present invention is advantageous by providing an increased striking force because the high pressure oil is used, in addition to the reaction force of the compressed nitrogen gas, when the piston is lowered to strike the chisel.

Abstract: A pneumatic reciprocator includes a cylindrical air cylinder concentrically mounted within a cylindrical manifold. A cylindrical sleeve valve is concentrically mounted for movement along the manifold by a pair of spaced O rings. Two sets of circumferentially arranged air holes in the manifold are alternately covered and uncovered by the O rings as the sleeve valve is moved to selectively pressurize and vent opposite sides of the piston in the air cylinder. Movement of the sleeve valve is controlled by stops on the movable bed of a surface grinder that is controlled by the air cylinder.

Abstract: A hydraulic drive system for a machine element performing in one work cycle a sequence of motions comprising a rapid feed motion, a working stroke under load and an oppositely directed rapid-return motion. The drive element includes a hydraulic cylinder having three working surfaces A.sub.1, A.sub.2, A.sub.3. Motion control is effected by an electro-hydraulic follow-up control valve with a pre-setting device controlled by a stepping motor and a mechanical actual-value feed-back device. During rapid feed motion, the relatively small working surface A.sub.1 is subjected to the output pressure of the follow-up control valve only, while during the working stroke the pressure acts additionally on the working surface A.sub.3. The rapid-return movements of the piston of the cylinder are controlled by applying pressure to the working surface A.sub.2, or by relieving pressure from the two other working surfaces A.sub.1 and A.sub.3.

Abstract: In the hydraulic breaker according to the present invention, oil pressure at a fixed value always flows in the circuit at a low pressure side whenever the piston is raised or lowered, to prevent the need for an accumulator in the circuit at the low pressure side. At the same time, a high pressure oil is required during the raising and lowering of the piston, bringing about less of a change in the surge pressure, attributing to the fact that there is no need for an accumulator in the circuit at the high pressure side. Moreover, the hydraulic breaker of the present invention is advantageous by providing an increased striking force because the high pressure oil is used, in addition to the reaction force of the compressed nitrogen gas, when the piston is lowered to strike the chisel.

Abstract: A hydraulic control valve for a single-acting cylinder includes a valve housing having a cylindrical valve bore. A supply port present in the valve housing is in communication with the valve bore, as is a discharge port and a delivery port. A valve pin is slidable within the valve bore between first and second pin positions, the valve pin including a pin groove positionable to establish communication at the first pin position between the supply port and the delivery port to the exclusion of the discharge port. The pin is slidable from the first position to the second position to establish simultaneous communication with the pin groove between the supply port, the discharge port and the delivery port.

Abstract: A pump jack of the type comprising a rocker arm pivotably mounted intermediate its ends on a support member, said rocker arm being divided by said pivot mounting into a sucker-rod limb and a drive limb wherein the improvement comprises a pneumatic motor pivotably attached to the drive support member and further pivotably attached to the mounting base of the pump jack to provide the power to reciprocate the pump jack. The working fluid of said pneumatic motor being natural gas which is available from the well casing of the well without any interference with the flow of the oil in the oil tube of the well thereby making use of an energy source available at any oil well without having to provide gasoline to drive a rotating type gasoline engine or electricity to drive an electric motor usually of the rotating variety.

Abstract: A control device for working cycles of a self-propelled pneumatic boring device with a non-rotatable axially displaceable impact piston controllable by control edges of a control sleeve supported axially non-displaceably but rotatably and at its front end forming a control head with the control edges. The control head engaging in a cylindrical recess at a rear end of the impact piston cooperates with a radial main control opening formed in the impact piston in the vicinity of the recess. The control edges form two different pairs of the control edges, offset peripherally as well as axially such that respectively in one rotated position of the control sleeve only one of the pairs is aligned for cooperation with the main control opening. The impact piston is formed with at least one additional control opening which cooperates with the other pair and has a flow cross-section considerably smaller than that of the main control opening.

Abstract: A petroleum pumping unit which is especially suitable for use in remote oil fields and under unpredictable pumping conditions is disclosed. The petroleum pumping unit of the present invention, which is easily movable between a folded, collapsed position for storage and shipment and an erect position for pumping operations, includes a horizontal support platform on which is pivotally mounted a mast assembly including a pair of masts spaced outwardly from the centrally positioned well polish rod. The polish rod is engaged by a notch in a horizontal, vertically movable bridle and is powered by at least one pair of flexibly mounted hydraulic cylinders and associated piston rods attached to the bridle and positioned between the polish rod and the masts and parallel thereto. Vertical movement of the bridle and, therefore, the stroke of the polish rod is defined by upper and lower limit switches which are actuated by actuating means on the bridle.

Abstract: Apparatus for the continuous adjustment of the stroke amplitude of the piston of a jack, the latter having a control member of which at least part is in the form of a rod, which is movable in rotation and in translation and cooperates with the said piston, wherein said rod has an extension in the form of a differential piston which is movable in translation and in rotation within a cylinder and defining also in the latter a chamber with a large cross-section and a chamber with a small cross-section, the latter being permanently connected to a pressurized fluid source, said differential piston having an inner cavity in which is located a second rod immobilized in translation and which can be angularly oriented, said second rod being provided with a cam having two opposite edges which can cyclically uncover and cover, during the rotation of the differential piston, at least two openings respectively connected to the two chambers.

Abstract: Control device for the forward movement and rearward movement of self-driven pneumatic ram boring devices with an impact piston which is axially displaceable between two abutments in a tubular housing, with the axial forward movement and rearward movement of the ram boring device being controllable by rigid control edges of an adjustable control sleeve, the latter being supported on a bearing ring arranged in the rear part of the housing. Through the bearing ring there is led a part of the control sleeve forming a feed tube for the compressed air for connection to a compressed air hose, the sleeve having a piston-like control head containing the control edges; the control head engaging in a cylindrical recess at the rear end of the impact piston cooperates with radial control bores which are formed in the area of the recess in the impact piston. The control sleeve is mounted non-displaceably in the axial direction however rotatably in the bearing ring and is provided with at least four control edges.

Abstract: A Pneumatic impact drilling tool, particularly useful as a downhole pneumatic drill, includes a housing structure adapted to be connected to a string of drill pipe and supplied with compressed air therethrough. A hammer piston reciprocates in the housing structure along flexible feed and exhaust tubes. Compressed air is directed alternately to the upper and lower ends of the hammer to effect its reciprocation in the housing. The hammer is operable to strike an anvil bit member repeatedly to effect a drilling motion. At the upper end of the housing there is provided a removable annular plug member surrounding the tubular support in which the feeder tube is positioned. The annular plug member defines the volume of the space above the hammer piston and is related to the size of the feeder tube so that the feeder tube and plug member together determine the volume of air utilized at any selected air pressure and the timing of operation of the hammer position.

Abstract: A fluid operated control device which co-operates with reciprocating means, such as a pneumatically driven shaft. The device includes a main cylinder and piston backed at each end by valves which each include auxiliary cylinders and pistons. The valves provide signal inlets and outlets which can be cross connected to cause continuous reciprocation of the main piston. Alternatively, the valves are operated to displace the main piston selectively or are connected to a delay to vary the timing sequence. Stroke adjustment is possible by a rod attached to one of the auxiliary valves. The main piston is mounted on a shaft passing through the other auxiliary valves.

Abstract: A percussion drill comprising a cylinder housing, a striker piston slidably accommodated within said housing, a shank rod slidably mounted within said housing, said shank rod being adapted to be struck by said striker piston, a first chamber having a small sectional area continuously pressurized by hydraulic fluid for retracting said striker piston, a second chamber having a large sectional area intermittently pressurized by hydraulic fluid for advancing said striker piston, a selector valve mounted in said housing, said selector valve being connected with said first and second chambers, and a bushing adjustably mounted in said housing around the periphery of said striker piston so as to form a pilot operated valve between said bushing and the periphery of said piston.

Abstract: A piston and cylinder device with a piston mounted for reciprocating movement in the cylinder has on the outside of the cylinder an elongated mounting element comprising two guiding members on each of which a limit switch is mounted for positioning longitudinally of the cylinder. The limit switch is formed with a switch blade of ferromagnetic material and the piston has an annular rim constituted of permanent magnetic material. The switches can be adjusted longitudinally for the purpose of adjusting the stroke of the piston.

Abstract: In a pile driving hammer including a striker elevatable on guides by fluid pressure delivered to an operating fluid cylinder, and capable of being dropped to deliver a pile driving blow by exhausting fluid from the cylinder, a control system for the cylinder including a first cam carried by the striker and operable to cause delivery of fluid to the cylinder at the lower end of the stroke of the striker, a plurality of second cams carried by the striker and operable to cause exhaust of fluid from the cylinder at respectively different elevations of the striker, and remotely controlled apparatus for activating any selected one of the second cams.

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.

Abstract: In a liquid product measuring pump driven by an air motor having air valve controls for reversing the reciprocating motion of the air motor at the end of the stroke for controlling the liquid product measuring, an adjustable stop assembly including a quickly replaceable stop bar with an extendible threaded rod therein, the rod being minutely adjustable by an insert fitting on the mounting for the stop bar.

Abstract: As a drive in metal-cutting machines used for vibration cutting a hydraulic vibrator is proposed, which comprises a differential piston and a spring-balanced slide valve, which are made and arranged so as to ensure reciprocal successive communication between a pressurized chamber and discharge and inlet chambers. In said vibrator the smaller diameter d and the larger diameter D of said piston are in a relation of d = .sqroot.D.sup.2 /2, and as a result the piston reciprocates symmetrically with an equal speed in either directions. There is also provided a plurality of compensating chambers controlled by throttles of a variable section. Continuous regulation of the magnitude of the stroke of said differential piston is effected in the hydraulic vibrator over a large range.

Abstract: A portable and high-speed tool reciprocator for small tools, such as files, cutters, burnishing and polishing stones, leathers and the like, of a size easily held in one hand of an operator; fluid driven, preferably by a pneumatic fluid, the length of the reciprocatory stroke of which reciprocator may be adjusted, while in operative reciprocation, without the reorganization of its parts or the employment of extraneous gear, and the reciprocated tool may be selectively controlled to be either free or locked against rotation about its axis of reciprocation, while in operative reciprocation, without the reorganization of the reciprocator parts or the employment of extraneous gear, thus to enable the tool and its working face to move angularly relative to its axis of reciprocation and the holder, when free floating, or, when locked, to dispose the tool and its working face at some desired angle to tool reciprocation and the holder.

Abstract: In a hydraulic percussion rock drill the operation of the working fluid distributing valve is controlled to effect a variation in percussive blow energy and blow frequency by varying the piston hammer stroke. Actuation of the distributing valve is controlled by a remote controlled hydraulically actuated pressure control valve interposed in a fluid passage which conducts hydraulic fluid from the hammer bore to actuate the distributing valve. Substantially infinite variation of hammer impact blow energy between high and low limits provides for selecting the maximum penetration rate of the drill for any type of rock conditions. The hydraulic rock drill is connected to a source of hydraulic fluid supplied to the drill at substantially constant fluid power by a variable displacement constant power hydraulic pump.