Abstract: Disclosed is a hybrid excavator which reduces the impact generated at the start of the operation of the boom cylinder, or the like, of a hybrid excavator. The hybrid excavator according to the present invention comprises: a hydraulic pump motor connected to an electric motor and operated in the forward or reverse direction; a hydraulic cylinder connected to the hydraulic pump motor and operated in an expanding manner; a first and second hydraulic valve installed in a first and second passage, respectively, between the hydraulic pump motor and the hydraulic cylinder, for blocking the first and second passages when switched by an external control signal; a third hydraulic valve installed in the connecting path connected to first and second dividing passages.

Abstract: A control system for a work implement on a machine is disclosed including a first hydraulic circuit, a second hydraulic circuit, and a controller. The first hydraulic circuit includes a hydraulic cylinder assembly, a pressurized fluid source, and a fluid tank. The hydraulic cylinder assembly includes a head end, a rod end, a cylinder, and a rod. The pressurized fluid source and the fluid tank are selectively connected to the head end or the rod end. The second hydraulic circuit includes a valve configured to receive a connection to tank signal and selectively connect the head end or the rod end to the fluid tank. The controller is configured to generate the connection to tank signal.

Abstract: Hydraulic machine, in particular hydraulic motor, comprising a casing, a differential piston (4) having a region of large cross section and a region of smaller cross section, which can slide with a reciprocating movement respectively in the casing and in a housing coaxial to, and of smaller diameter than, the casing, the piston separating two chambers of the casing and being provided at the location of its large cross section and its small cross section with sealing lips (48, 49) which are oriented in opposite directions and which face one another. The sealing lips (48, 49) are provided on detachable circular rings (50, 51), and the piston (4) is molded in one piece.

Abstract: A submersible pump includes a pump valve configured to switch the pump between first and second states in which a piston is respectively extended and retracted. The pump valve includes first and second components that reciprocate between corresponding first and second positions. The pump is in the first state when both components are in their corresponding first position. The pump is in the second state when both components are in their corresponding second position. Neither the valve nor the pump is hydraulically locked at any time during normal operation.

Abstract: A fluid distributor cylinder is for a percussive drill assembly that includes a casing having an inner circumferential surface defining a central bore, a central axis extending through the bore, a bit movably coupled with the casing and a piston movably disposed within the casing bore. The distributor cylinder includes a generally tubular body disposeable within the casing bore and having first and second ends, a central axis extending generally between the first and second ends, an outer circumferential surface. At least a section of the outer surface is configured to engage with the inner surface of the casing so to form an interference fit between the body and the casing. The cylinder includes an exterior thread and/or a radially-extending shoulder configured to releasably engage with the casing inner surface so as to substantially prevent axial displacement of the distributor body with respect to the casing.

Abstract: A downhole ram pump. A downhole pump system includes a flow restricting device which variably restricts fluid flow through an opening, the restricting device vibrating in response to the fluid flow, thereby alternately increasing and decreasing the fluid flow through the opening; and a pump device which generates a pressure differential in response to vibration of the restricting device. Another downhole pump system includes a flow restricting device which vibrates in response to fluid flow through an opening, thereby alternately increasing and decreasing the fluid flow through the opening, a pressure differential across the restricting device variably biasing the restricting device to increasingly restrict the fluid flow through the opening, and the pressure differential alternately increasing and decreasing in response to respective alternate increasing and decreasing flow through the opening; and a pump device which generates differential pressure in response to vibration of the restricting device.

Abstract: A percussive apparatus comprises a body inside of which a striking piston is mounted in a cylinder bore. Two axially offset pieces are mounted inside the cylinder bore of the body while being concentric to the piston, and a deformable washer is placed between said pieces. One of the pieces is stationary with regard to the other piece that, however, is mounted in a manner that enables it to slide inside the cylinder bore and to be displaced in the direction of the stationary piece while being subjected to the action of the supply pressure of the hydraulic fluid that acts upon the surface of the moving piece facing away from the side opposite the stationary piece. The displacement of the moving piece causes the elastic washer to deform in order to create a passage with a variable cross-section on the return circuit of the hydraulic fluid to the reservoir or on a circuit that diverts, to the return circuit, a portion of the delivery flow of the apparatus whereby regulating the input pressure.

Abstract: The invention relates to a control valve, a percussion device and a method of controlling a working cycle of a percussion device. A percussion device (1) for breaking rock includes an impact element (8) controlled by a control valve (2). The control valve includes a control element (5) arranged to control channels (7b) leading to a working pressure surface (9) of the impact element (8). The control element, during a working cycle of the control valve, is arranged to open and close pressure channels at several connecting moments so that during one working cycle of the valve, several impact pulses are arranged to be produced.

Abstract: An asymmetrical vibrator is provided, which is actuated by compressed air. The vibrator operates in a case, which has two bores disposed parallel on opposite sides of the casing. One of the bores is smaller than the second bore and the piston operating in the small bore is called the slow piston, since it is actuated with air to a relatively slow motion and the piston operating in the second larger bore is called the fast piston, since it is moves at a larger speed when driven directly by the compressed air. The asymmetric vibration motion can be employed to transport materials upwardly in factories and assembly stations. The air operated asymmetric vibrators need low maintenance and do not entail the spark dangers caused by the presence of electrical wiring for electrical drive motors.

Abstract: A double-acting reciprocating motor with a uni-directional fluid flow path comprises a piston disposed within a cylinder. Within the cylinder, the piston defines a first chamber between the piston and a cylinder base and a second chamber between the piston and a cylinder head. Fluid is introduced into the first chamber of the motor through an inlet port associated with the cylinder base. A pass-through valve controls the flow of fluid from the first chamber to the second chamber. An outlet valve regulates the draining of fluid from the second chamber through an outlet port associated with the cylinder head. Fluid pressure within the first chamber urges the piston towards the cylinder head when the pass-through valve is closed and the outlet valve is open. The piston surface facing the second chamber is larger than the piston surface facing the first chamber, so the piston moves towards the cylinder base when the pass-through valve is open and the outlet valve is closed.

Abstract: A hydraulic actuator has a housing, a piston drive chamber in the housing, a fluid inlet into the chamber, and a piston reciprocable in the drive chamber. The piston has diametrical steps exposed to fluid under pressure to cycle the piston. A sleeve spaced from and surrounds over a length of the piston to define a return chamber therebetween. The housing has first and second seats. The first seat and a first surface of the sleeve define an exhaust valve, which has an exhaust port, for the return chamber. The exhaust port is opened and closed by reciprocating the sleeve. The second seat and a second surface of the sleeve an inlet valve for the return chamber. Reciprocating the sleeve opens and closes the return chamber to the drive chamber. The housing also has a bore through which a portion of the sleeve reciprocates to close the exhaust valve and seal the drive chamber.

Abstract: The hydraulic reciprocating mechanism has a housing and a piston located reciprocably in the housing. The piston and housing define a supply chamber and a return chamber. The return chamber has valve seats at either end. There is an inlet to the supply chamber for pressurized hydraulic fluid and an exhaust outlet from the return chamber. An interconnecting passage extends between the supply chamber and the return chamber. A single popper valve is located reciprocably in the return chamber and is moved by hydraulic forces between positions in which it seats on the respective valve seats. In one position of the popper valve it closes the exhaust outlet and opens the interconnecting passage to admit hydraulic fluid from the supply chamber to the return chamber. This has the result hydraulic fluid in the return chamber drives the piston in one direction.

Abstract: An air operated reciprocating piston pump having a differential area piston is provided with an annular shaped airfoil device having a chevron cross-section and which is located beneath the bottom air intake plate to utilize increasing air velocity at the initiation of bottom changeover in order to assure more reliable changeover.

Abstract: The present invention relates to a valve assembly (10) which is mounted on a part (piston unit 40) of an air motor (10) arranged for reciprocating movement in a housing (cylinder 12). The valve assembly includes a first valve unit (50), which is mounted on one side of the part (40), and a second valve unit (70), which is mounted on the other side of the part (40). The second valve unit is connected to the first valve unit (50) by means of the part (40) for common movement with the first valve unit relative to the part (40) when the valve assembly is switched as the part (40) reaches one of its two end turning-positions.

Abstract: A modular digital actuator is formed by interconnecting a plurality of modules. Each of the modules includes a housing having a pair of different sized axially extending cylinder sections in which is received a T-shaped piston with the top of the T mating with the larger cylinder and the leg of the T forming a piston in the smaller cylinder. The leg of the T is hollow and forms a cylinder to receive an axially extending piston forming shaft to thereby provide three preferably different sized cooperating piston and cylinder areas, one formed in the cavity or hollows of the leg of the T, a second formed between the top of the T surrounding the leg of the T and the junction between the larger cylinder section and smaller cylinder section and the third formed in the smaller cylinder section between a closed free end of the smaller cylinder section and the leg of the T surrounding the piston forming shaft. The top of the T forms a piston wall in a fourth hydraulic cavity.

Abstract: A hydraulic positioning means is provided which includes means for selectively allowing or prohibiting the flow of the first hydraulic fluid under the operating pressure. It also includes means in the hydraulic positioning means for selectively positioning the workpiece to a plurality of predetermined locations for performing work operations thereon in response to allowing or prohibiting the flow of the first pressurized hydraulic fluid under the operating pressure. Means are also furnished for supplying the first pressurized fluid under the operating pressure to the hydraulic positioning means for such selective positioning of the workpiece. First fluid conduit means transfer the first pressurized fluid at said operating pressure from the pressurized fluid supply means to the hydraulic positioning means. A hydraulic impact load cushioning means is also bifurcatedly provided.

Abstract: A pneumatic linear vibrator comprises a piston guide sealed on one side and delimited by detachable end parts (14,16), a piston (10), a sound-absorbing pipe (52) which forms the housing, and means for supplying and removing a gaseous or vaporized pressure medium. Relative motion between the guide with the end parts and the piston is ensured by automatic alternating delivery of the pressure medium to a working volume (V,V1,V2) located on one face of the piston. The piston (10) has a longitudinal axial bore (22) with a snap ring groove (26) in the region of the ends of the longitudinal median plane of the piston. The snap ring grooves are connected to a face of the piston (10) by at least two axisymmetric channels (27) which run in the axial direction (A) and are sealed off from the longitudinal axial bore (22) of the piston (10).

Abstract: Method and apparatus for recovering leaked fluid or directing fluid flow or propagation through utilization of negative pressure pulses occurring in a pressurized fluid system. The invention has particular application in double acting hydraulic fluid motors where leakage of hydraulic fluid past the output shaft seal may be efficiently collected and redirected into the pressurized hydraulic fluid system through utilization of negative pressure pulses that are developed periodically by fluid direction changes during operation of the hydraulic fluid motor.

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: This invention relates to an air motor having a snap-acting overcentering spring mechanism for snapping the valving of the air motor between first and second positions as the piston completes each stroke in the cylinder to ensure reliable stall-free operation of the motor.

Abstract: A fluid energized double acting motor is provided for use as the drive for reciprocating mechanisms such as paint pumps for airless spray painting. A piston within the pump housing is moved by pressurized fluid controlled by an automatic reversing valve including spaced check valves. The check valves are selectively seated and unseated by a spring biased piston and fluid pressure controlled valve actuator assembly. The reversing valve system includes anti-stalling features and is of single, low cost, field repairable nature. The motor system also includes features to prevent chattering oscillation due to abrupt changes in motor load.

Abstract: There is described apparatus for scabbling concretw which includes a hollow cylinder block having a top and bottom plate between which plates there is provided a smooth sided hollow cylindrical cylinder liner. The piston for reciprocation within the cylinder liner is also provided.

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 differential hydraulic jack with a damping system for the control of electric circuit-breakers is provided with a floating ring which produces a damping action at the end of travel and is also provided with a damping extension stud which forms part of the jack piston and penetrates into the damping ring. No provision is made on the jack piston for any packing ring forming a seal with the jack cylinder. The damping ring carries two projecting lips constituting a double valve which forms a leak-tight seal with the bottom face of the jack piston and the internal face of the cylinder end. At the end of the travel of the piston, the damping ring forms a double sealing valve for shutting-off the supply/drain orifice of the jack.

Abstract: The fluid-powered, reciprocating motor includes a cylinder having an inlet chamber and an outlet chamber, a differential area piston mounted in the cylinder, and an output or power shaft connected to the piston. A pressurized fluid, either a gas or a liquid, is continuously introduced into the cylinder inlet chamber and acts on the smaller piston area to move the piston in one direction. A small stream of the fluid flows from the cylinder inlet chamber into the cylinder outlet chamber through a control passage in the piston and is exhausted from the cylinder outlet chamber through an outlet passage until the piston is moved far enough for a valve member carried by the piston to close the outlet passage. Fluid pressure subsequently building up in the cylinder outlet chamber acts on the larger piston area and moves the piston in the opposite direction.

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: 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: A piston vibrator comprising a cylindrical housing having a chamber with a free floating piston therein. The free floating piston is axially moved by a pressurized medium. Piston amplifying structure is provided for regulating the effective mass of the piston and thereby the amplitude and frequency of movement thereof in said cylindrical housing.

Abstract: A hydraulic percussive machine comprising a piston and cylinder with a dashpot at the front end to cushion overtravel of the piston. Heat is removed from the dashpot by admitting pressure fluid to the return stroke chamber through a front chamber and the dashpot. On the pressure stroke fluid from the return stroke chamber is admitted to the working stroke chamber in one case by causing all flow to take place along that route and in the other place by having two feeds to the working stroke chamber with a flow restrictor in the direct feed line.

Abstract: A solenoid operated metering pump for displacement of exact amounts of fluid pumped by reciprocation of pumping piston incorporating integral check valve has an elongated valve housing with solenoid operator serving as pump actuating means attached to one housing end while the other housing end is adaptable to serve as the fluid pumping means including an appropriate housing bore passing therethrough and adaptable to receive a differential diameter piston assembly slidably movable therein to reciprocate when solenoid operator becomes electrically cycled inducing fluid flow through appropriate pump chamber created therein between piston and housing bore portion provided with fluid supply port having a detachable check valve with a simple floater for a directional flow control therethrough, means of piston actuation from a first position checking flow and discharge of the fluid delivered to the pump chamber to a second position discharging exact fluid quantity per each stroke of pump reciprocation, and means of

Abstract: Hydraulically powered percussive apparatus for breaking rock, drilling etc. in which a combined spool valve and hammer reciprocates in the bore of a cylinder structure. A high pressure fluid inlet leads to the bore and a low pressure outlet leads from the bore. A fluid flow passage communicates with the bore at two axially spaced locations. As the hammer reciprocates, it cyclically connects, via the bore, the inlet to the passage and the outlet to the passage. Pressures in the inlet and outlet fluctuate between fairly narrow limits whereas the pressure in the passage fluctuates between a pressure approximating inlet pressure and a pressure approximating outlet pressure. The hammer has two operating faces. The first of these is exposed to the relatively steady inlet pressure and the second is subjected to the widely varying pressure in the passage.

Abstract: A new control system is provided for a reciprocating fluid stroke motor of the type which is pressured at its rod end, reciprocation being achieved by intermittent exposure of its full blind-end face to the pressure fluid to overcome the pressure applied to its smaller rod-end face. The control means includes a valve for a passage through the piston, with adjustably-positioned trip-stops for shifting the valve between open and closed positions. The valve is biased to snap fully open when the piston movement toward its opening-stop opens it slightly and remain open until striking the closing-stop. Monostable or bistable trip-switch types of biasing means may be used, and unless one holding the valve closed with no fluid pressure is chosen, resumption of pressure supply after discontinuance will cause an initial retraction of the piston to its starting position, allowing time for the controlled apparatus to attain acceptable speed.

Abstract: A mechanism for generating a high impact force for hammering, pounding, stamping, forging or similar operations. A piston is slidably mounted in a fluid pressure chamber, and has a larger cross sectional area at one end of the chamber than at the other end thereof. A fluid is introduced into the chamber under pressure, and exerts a net axial force on the large cross section end of the piston. One end of the piston outside the chamber forms a cam, which is engaged by a spring loaded cam follower to prevent axial movement of the piston until the force thereon exceeds a predetermined value. When the force on the piston exceeds said value, the cam is suddenly disengaged from its follower, permitting rapid movement of the piston under the fluid pressure. When the piston reaches the end of its travel, fluid is permitted to leave the chamber so that the pressure on the piston rapidly decreases, and the spring loaded cam follower acts on the cam to return the piston to its initial position.

Abstract: The present invention relates to pneumatic impact devices and can be used to the best advantage for making holes in compacted soils.The device is provided with a hollow casing which accommodates a stepped ram with the maximum-diameter step in its front part. This step has longitudinal channels which open at one end into a working chamber defined by the maximum-diameter step and the side walls of the casing and serving for receiving compressed air from the compressed air line, with the air moving the striker to impart a blow after which it is discharged through holes in the casing.

Abstract: In a first embodiment an improved, hydraulic-powered paving breaker is depicted in which a novel arrangement is provided for internally lubricating the breaker. In the arrangement an elbow taps off discharging pressured hydraulic fluid from the breaker and, through a manifold line coupled to fittings, which are in penetration of the housing of the breaker, admits hydraulic fluid into the breaker to lubricate a reciprocating plunger, moil, and O-ring seals. In an alternative embodiment, a conduit is formed entirely within the breaker for the same purpose. In both embodiments a restrictor device is interposed between the supply of pressured hydraulic fluid and the points of fluid injection to insure a uniform supply of fluid to the latter at a given prescribed pressure.

Abstract: An improved fluid motor having only two moving components, a reciprocatable piston and a fluid actuated valve spool. The piston is supported for linear movement in a piston support bore of a barrel assembly, and is moved in alternating directions by the operation of selected porting of a pressure fluid selectively admitted against differential piston pressure faces. The valve spool is disposed in an inner bore in the piston and is alternately driven in opposing directions by automatically controlled and selective application of fluid pressure. The fluid motor experiences no mechanical impact between the valve spool and the piston.

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 fluid operated tool is provided which is operable particularly for purposes of causing the linear movement of a tool member in at least one direction. The tool includes a main body, a trigger, an On-Off valve spool, a main piston, a reversing assembly, an accumulator and means for attaching the tool member to the tool. The main body is provided with a plurality of bores in which the On-Off valve spool, the main piston, the reversing assembly, and the accumulator are respectively positioned, and a plurality of channels which function to interconnect the bores. The On-Off valve spool is supported in one of the bores in such a manner as to be operatively connected to the trigger whereby the valve spool moves between first and second positions in response to the actuation of the trigger thereby to selectively open and close various ones of the channels formed in the main body.

Abstract: This invention relates to a linear hydraulic motor or actuator, more especially to a hydraulic motor in combination with a piston pump, serving to inject liquid fertilizers into a water pipe line.