Abstract: Provided is a two-piston hydraulic striking device that has stable operativity. This two-piston hydraulic striking device includes two striking mechanisms for striking one transfer member. Each striking mechanism has a pressure receiving area ratio between the front and rear of a piston thereof set in such a way that the two striking mechanisms have the same cycle time.

Abstract: A percussion device for a hydraulic rock drilling machine (1) including, inside a cylinder (4), a to and fro moveable impact piston (3), which is provided with a land portion (12) for cooperation with a braking recess (11) in the cylinder (4) for the establishment of a braking chamber in advanced positions of the impact piston, wherein a throttle slit (17) is arranged to be established between the land portion (12) and the braking recess (11). A pressure channel (14), being connected to a pressure medium source, is arranged to debouch in the cylinder (4) between the piston guiding device (6) and a position of the land portion (12) in a most advanced position of the impact piston (3). The invention also concerns a method and a hydraulic rock drilling machine.

Abstract: A percussion piston for a rock drill machine having a pilot cylinder, a distributor and a pressure medium includes a control edge configurable to cause a change in the position of the distributor in a direction parallel to the axial direction of the percussion piston as the percussion piston moves in the impact direction (A) in relation to the pilot cylinder. The control edge of the percussion piston includes at least one notch provided on the outer periphery of the control edge and arranged to cause a start of a state change for the distributor before the control edge of the percussion piston passes by a corresponding control edge provided on the distributor or pilot cylinder.

Abstract: The rotary percussive device includes a casing forming a support, a striking mechanism equipped with a longitudinal body, rotatably mounted in the casing along the axis of the body, including a cylinder extending along the axis of the body, a striking piston slidingly mounted inside the cylinder and intended to strike a shank coupled to a drill rod, and a distribution device arranged to control an alternating movement of the striking piston along the axis of the body, and a motor arranged to drive the body of the striking mechanism in rotation along an axis of rotation substantially coinciding with the axis of the body. The striking mechanism includes a closing lid mounted on the body and arranged to close one of the ends of the body, the closing lid being coupled in rotation to an output shaft of the motor and at least partially including the distribution device.

Abstract: A hydraulic hammer is disclosed having a piston and an accumulator membrane disposed external and co-axial to the piston. Additionally, a sleeve is disposed between the piston and accumulator membrane, wherein the sleeve has a plurality of radial passages formed therein that fluidly connect the accumulator membrane with the piston.

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: A percussive hammer for delivering impacts driven by oil which is quickly applied under pressure derived from a system supply and from a source of compressed gas.

Abstract: The invention relates to an arrangement in connection with a hydraulically operated impact device, such as a breaking apparatus. The impact device includes a percussion piston, conduits for feeding pressure fluid into and out of the impact device, and a pressure accumulator. According to the inventive idea, the pressure accumulator is formed as an annular structure surrounding the percussion piston. It consists of sleeve-shaped pressure chambers that are separated by a sleeve-like diaphragm arranged between a frame and a sleeve. The pressure chambers are formed such that the inner circumference of the sleeve placed around the frame and the outer circumference of the frame are provided with recesses opposite one another.

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: This invention relates to a cyclic hydraulic actuator, and more particularly to an actuator for a rock drill and includes: a housing; at least two chambers in the housing; a fluid passage between a first of the chambers and the outside of the housing for feeding a liquid at supply pressure to the chamber during operation of the actuator; a fluid passage between a second of the chambers and the outside of the housing for exhausting liquid from the second chamber during operation of the actuator; a piston reciprocable on an axis in at least the first and second chambers with the piston including an exposed piston area in each of the two chambers for causing, with the liquid at supply pressure, reciprocation of the piston; an inlet valve for opening and closing the second chamber to liquid at supply pressure in the first chamber; an exhaust valve for opening and closing the exhaust passage; the inlet and exhaust valves, chambers and exposed piston areas being so arranged that during cyclic operation of the actua

Abstract: An impulse motor for a hand held hammer machine comprises a housing (10) with a cylinder (11) therein, in which a reciprocating drive piston (40) via a gas cushion in a working chamber (44) of said cylinder (11) repeatedly drives a hammer piston (15) to impact on and to return from a tool (20) carried by the machine housing (10). The drive piston (40) has an axially protruding reduced diameter damping piston (50) thereon adapted to prevent piston encounter collision by arresting the return movement of said hammer piston (15) towards the drive piston (40) in a cooperating damping cylinder (51) provided on the hammer piston (15). The damping piston (50) has two diameterical steps (64,65) formed thereon, of which an outer step (64) is long and has a clearance relative to said damping cylinder (51) enabling during arresting a braking action therebetween by gas friction in said clearance.

Abstract: A pneumatic type of reciprocating movement device capable of a high cycle speed over a short stroke. A rod member with a flange is slidably mounted in a cylinder member such that the flange divides a cavity in the cylinder into a left and right portion. Intake and exhaust passages are moved in and out of communication with the cavity sides by the moving interface of the rod and cylinder, such that an alternating force is exerted on the flange sides causing the flange and rod member to move in a reciprocating motion without the use of an auxiliary system of valve switching.

Abstract: Miniature engine operated by an expanding gaseous fluid, which comprises a cylinder (18), piston (20) and inlet valve (29), the upper part of the piston (20) cooperating with a radially expansible resilient diaphragm (28), which is secured to the piston (20) and performs momentarily a pneumatic seal-engagement function along the periphery of said cylinder (18) during the gaseous expansion phase.

Abstract: A cylinder (15) is reciprocable in the housing (11) of a hydraulic percussive tool and a piston hammer (16) is reciprocable in the cylinder. The force between the cylinder and the housing is constant during the cycle of reciprocation and as a result the housing (11) is practically not vibrating at all. The piston hammer (16) and the cylinder (15) are coupled together to move conjointly during a part of each forward stroke of the hammer piston, which ensures the timing of the reciprocation of the hammer piston 16 and the cylinder (15).

Abstract: An all-hydraulic impactor for percussion tools and the like embodying an oil accumulator and an annular sleeve valve. Hydraulic fluid is initially supplied to the accumulator at full supply pressure and is then charged, for example, to three times the supply pressure by a differential piston arrangement. The impactor of the invention minimizes the required volume of the accumulator.

Abstract: A hammer or impactor apparatus including improved motive fluid means cooperable with spring bias means to reciprocably drive a hammer element and an improved process of hammer cycling achieved thereby.

Abstract: A hydraulic percussion apparatus comprising a body, a cylinder in the body and a percussion piston reciprocating in the cylinder. A distributing valve moves in a valve housing. A valve for starting and stopping the percussion apparatus is provided. A hydraulic pump and hydraulic channels form a percussion circuit with a gas/liquid pressure accumulator. A distributing valve circuit and a free circulation circuit are provided for the pump which are parallelly coupled with the percussion circuit, which circuits are connected to the pump and to the start-and-stop valve which has positions for controlling pressure in the circuits. The start-and-stop valve has a middle position during which pressure in the percussion circuit rises up to a predetermined value while the distributing valve circuit remains closed independent of the pressure in the percussion circuit.

Abstract: An impactor apparatus including novel means for actuation of a motive fluid flow control valve or comparable motive fluid control means.

Abstract: An internal combustion engine, a fluid motor or a pump includes a cylinder block enclosing an elongated cylindrical bore. A double headed piston is slidably mounted within the bore. The piston and cylinder block are rotatable relative to each other about the longitudinal axis of the bore. Rotation is imparted by a sinusoidal cam and a cam follower. Reciprocation of the piston within the bore is accomplished along with corresponding rotational movement of the cylinder block. Opposed ends of the cylinder block include openings which are aligned with and periodically communicate with exhaust and intake chambers. Porting collars are slidably mounted to the cylinder block and are stationary relative to the cylinder.

Abstract: A demolition tool for breaking solid materials, particularly rock or concrete in tunnelling, mining, demolishing and excavating applications. The tool has a single impactor (1) of the projectile type which is driven by high pressure liquid towards the material to be broken. A gas pressure accumulator (2) is included for storing high pressure energy. This energy is transferred at a high rate through short, wide and streamlined channel means (8, 13, 57, 9), having high capacity and low flow losses, to the impactor (1). Valve means (7) is provided in the channel means so that the accumulator (2) can be recharged during the return stroke of the impactor, giving a high repetition rate. A low pressure annular accumulator (5) drives the impactor during the return stroke.

Abstract: An impact tool for mining, demolition work and the like. An energy storing device such as a coil spring, when compressed, accelerates a hammer to deliver a blow to a working tool. The hydraulic cocking mechanism has a compression chamber and a bias chamber. A shaft extends through the compression chamber and into the bias chamber. The shaft has an annular stop attached to it and reciprocally carries a compression sleeve above the annular stop. A bias member extends into the bias chamber. Input hydraulic pressure urges the bias member to press the compression sleeve into seating contact with the annular stop to define a piston. Hydraulic input pressure acting at the same time below the piston urges the shaft upward to cock the spring. At the top of the stroke, ports and passages reduce the pressure difference above and below the piston to allow the spring to force the shaft down for impact. On the downstroke, the compression sleeve and annular stop separate.

Abstract: A hydraulic impact device in which a hammer member having a piston portion is reciprocally disposed in a cylinder, a reciprocating sleeve valve is disposed within the cylinder and surrounds the hammer member. The sleeve valve has a first peripheral seal with an upper portion of the cylinder and a second peripheral seal with the lower portion of the cylinder so that an annular cavity is formed between the first and the second peripheral seals. The bottom portion of the sleeve valve forms a single seal with the upper portion of the piston section. A pressure relief valve is situated between the inlet to said annular cavity and an annular cavity below the piston portion to insure that the pressure in said annular cavity is greater than the pressure in the cavity below the piston portion and the sleeve valve thus effecting a sealing force between the sleeve valve and the upper face of the piston portion. An energy storage means is provided for receiving energy from said ram member during its upward stroke.

Abstract: A hydraulically operated reciprocating piston and a differential force operated valve are both in continuous fluid contact with a pressurized cushion chamber as well as the piston chamber pressure. The valve position is a function of the cushion chamber pressure. The cushion chamber pressure is a function of the axial position of the piston. The values of these functions are such that the piston is reciprocated when the machine is operated. The valve is a sleeve coaxial with the piston.

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: In a hydraulic striking device having a reciprocating piston there are first and second cylindrical spaces surrounding the piston, the first space continuously communicating with a high pressure circuit and the second space alternately communicating with the high pressure circuit and a low pressure circuit. A special sleeve-shaped control valve in the second space reciprocates axially of the piston to achieve the desired operation.

Abstract: Impact tools are described which are capable of developing percussive forces for rock drilling, seismic exploration and other repetitive high force applications. Each of the tools contains a hammer and a valve which may be hydraulically actuated so as to constitute a hydroacoustic oscillator. The valve is actuated in one direction by being engaged by the hammer and in the other direction by fluid pressure means. The fluid pressure means may be controlled by varying the fluid pressure magnitude which applies forces to the valve to effect the movement thereof so as to control the frequency of oscillation of the hammer (i.e., impact blow frequency). Control may also be provided over the hammer stroke and the blow energy.

Abstract: An hydraulic rock drill having an hydraulically reciprocable hammer piston arranged to pound an anvil carrying a drill string. A sleeve type shiftable valve periodically engaged by the piston to effect alternate application to and relief of pressurized hydraulic fluid from the piston cylinder to reciprocate the piston. A constant supply of pressurized hydraulic fluid to actuate the piston is provided by a surrounding reservoir. Hydraulic feed means responds to a predetermined displacement of the anvil relative to the housing to feed the housing relative to the work in accordance with the progress of the anvil. Hydraulic means serves to cushion rebounding actions of the anvil; and means is provided to apply cooling fluid to the sliding surfaces of the tool during its operation.

Abstract: A striking apparatus has a body which carries a tool and which has a cylinder space, a piston structure within the space, and a sleeve-type distributor valve within the cylinder and around the piston. Flow of hydraulic fluid supplied to the body under pressure is controlled by the valve and piston to cause the piston to reciprocate, striking the tool. The sleeve valve has an extension portion which controls flow through a canal in the piston to a valve operating distributor space and limits flow of liquid under pressure to an outlet canal to a relatively short interval in the operating cycle, thereby reducing the amount of liquid wasted.

Abstract: A ram device has a drop hammer connected to the piston of a lifting cylinder which is connected by means of short and wide ducts to a control apparatus for admitting compressed air into the cylinder and for discharging the air from the cylinder beneath the piston, control apparatus directly communicating with the ambient air so as to allow a rapid escape of the air through large air vent ports from beneath the piston. In particular this control apparatus is directly mounted on the cylinder, or is included in an extension of this cylinder.

Abstract: An hydraulically operated striking apparatus for driving a rock drill or the like comprises a body having an axial, generally cylindrical, interior space with an inwardly protruding annular member. A cylindrical piston is positioned in the space in sliding contact with the protruding annular member, and the piston has canal means in its outer surface. The body, the annular member and the piston define two annular spaces and an annular distributing valve is slidably disposed within one of the spaces. The two spaces communicate with each other by means of the piston canal when the piston is in a first slidable position, and the protruding annular member prevents communication between the two spaces when the piston is in a second slidable position. The piston is provided with an axially disposed extension which, in combination with an outlet means, serves to permit a third, annular axial space to communicate with either an inlet means or an outlet means at all times.

Abstract: A hydraulically operated percussion apparatus comprising a housing in which a reciprocating impact piston is arranged to transfer impact energy to an impact tool, pressure chambers defined between said housing and said piston, and a channel system including a high pressure and a low pressure branch for conducting hydraulic pressure fluid to and from the pressure chambers, a first one of said chambers containing a movable distribution valve member responsive to the movements of the piston for alternately connecting said first chamber to said high pressure branch and said low pressure branch, respectively, characterized in that said valve member is arranged to be transported by the piston when moving in one direction, and responsive to the movement of the piston in the other direction to be acted upon by the pressure fluid to move in said other direction by means of hydrostatic pressure, said valve member having a longer path of movement than the impact piston and being arranged, at its movement in said one dir

Abstract: A hydraulic impact device has a hammer member carrying a piston which is reciprocally disposed in a cylinder chamber to form an expansible chamber. When the expansible chamber is pressurized, the hammer is retracted against an air spring or other energy storage device by the high pressure. A sleeve valve is reciprocally disposed in the cylinder chamber between the piston and the energy storage device and is held against the piston by an imbalanced fluid pressure as the hammer is retracted against the spring. When the piston and sleeve valve have been retracted to a predetermined position, high pressure fluid is ported between the sleeve valve and piston to hydraulically separate the two members.

Abstract: Impact tools are described which are capable of developing percussive forces for rock drilling and other repetitive high force applications. A hydroacoustic oscillator contained in such tools includes a hammer and a valve mechanism which is actuated by the hammer for controlling the flow of pressurized fluid so as to establish pressure variations which sustain the oscillation of the hammer. A number of alternative valve mechanisms are disclosed, each including a valve element, the motion of which is controlled by controlling the flow of fluid with respect to the valve element as the hammer and valve element move relative to each other. Such flow control is afforded by chambers defined by the valve element; hydraulic fluid flow with respect to which is controlled so as to determine the deceleration of the valve element and the motion of the element in its actuation by the hammer.

Abstract: Impact tools are described which are capable of developing percussive forces for rock drilling and other repetitive high force applications. A hydroacoustic oscillator contained in such tools includes a hammer and a valve mechanism which is actuated by the hammer for controlling the flow of pressurized fluid so as to establish pressure variations which sustain the oscillation of the hammer. A number of alternative valve mechanisms are disclosed, each including a valve element, the motion of which is controlled by controlling the flow of fluid with respect to the valve element as the hammer and valve element move relative to each other. Such flow control is afforded by chambers defined by the valve element; hydraulic fluid flow with respect to which is controlled so as to determine the deceleration of the valve element and the motion of the element in its actuation by the hammer.

Abstract: Impact tools are described which are capable of developing percussive forces for rock drilling and other repetitive high force applications. A hydroacoustic oscillator contained in such tools includes a hammer and a valve mechanism which is actuated by the hammer for controlling the flow of pressurized fluid so as to establish pressure variations which sustain the oscillation of the hammer. A number of alternative valve mechanisms are disclosed, each including a valve element, the motion of which is controlled by controlling the flow of fluid with respect to the valve element as the hammer and valve element move relative to each other. Such flow control is afforded by chambers defined by the valve element; hydraulic fluid flow with respect to which is controlled so as to determine the deceleration of the valve element and the motion of the element in its actuation by the hammer.

Abstract: Hydraulically driven percussion device, comprising a piston reciprocally movable within a body and striking against a tool, said piston defining with reference to the body two cylinder spaces, one of which continuously communicates with the high pressure duct and the other by the aid of a distribution means alternatingly connectable to the high pressure duct and the low pressure duct. At both ends of the piston there are breathing chambers opening into the free atmosphere. Within one of said two cylinder spaces a sleeve-like distribution means has been placed to encircle the piston and which distribution means, in order to move into a position such that movement of the piston directed towards the tool becomes possible, is controlled by means of grooves provided in the piston and in the body when the piston is in its end position farthest removed from the tool and only on condition that the pressure in the high pressure duct exceeds a pressure set with an adjustable valve incorporated in the body.

Abstract: Impact tools are described which are capable of developing percussive forces for rock drilling and other repetitive high force applications. A hydroacoustic oscillator contained in such tools includes a hammer and a valve mechanism which is actuated by the hammer for controlling the flow of pressurized fluid so as to establish pressure variations which sustain the oscillation of the hammer. A number of alternative valve mechanisms are disclosed, each including a valve element, the motion of which is controlled by controlling the flow of fluid with respect to the valve element as the hammer and valve element move relative to each other. Such flow control is afforded by chambers defined by the valve element; hydraulic fluid flow with respect to which is controlled so as to determine the deceleration of the valve element and the motion of the element in its actuation by the hammer.