Abstract: In a hydraulic pile driver (10), the lifting cylinder (34) acting on the driving weight (12) has an attached position indicator (46, 50), which produces a signal corresponding to the momentary position of the piston rod (32) of the lifting cylinder (34). This signal is used for reversing a 4/3-valve, by which the two working chambers of the lifting cylinder can be connected to a pressure line or return line.

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 hammer for driving a pile into the ground has a cylindrical barrel and an anvil sealed to an end of the barrel, a hammer piston mounted for reciprocation within the barrel towards and away from the anvil, hydraulic cylinders to lift the hammer piston away from the anvil, and a switch, responsive to an increase in fluid pressure in the space between the hammer piston and the anvil, to activate the lift means. The invention includes a method of driving a pile into the ground, in which the pile-driving impact is transmitted to the pile via a confined quantity of hydraulic fluid and the weight by which the impact is applied is lifted, to a position from which to apply a further impact, in response to an increase in pressure in the hydraulic fluid.

Abstract: An impact power tool for delicate hand working operations is provided which is especially adapted for detailed engraving, carving, and delicate stone setting applications. The power tool preferably includes a hand-held impact device, a piston received within the body of the device and shiftable therein for delivering impact energy to the device, conduit for delivering and venting motive fluid from and to the hand-held device for shifting of the piston, and a valve coupling the directing and venting conduits to the device in alternative fashion at rapid, variable, cyclical rate. The impact tool may be operated by connection to a standard source of pressurized air. The tool is capable of providing a greater range of impact strokes per second than conventional hand-held controlled impact tools, and thereby provides expanded capability for extremely delicate and fine engraving, carving and stone setting work.

Abstract: A piston vibrator adapted for use in vibrating insulated structures through a rod or other vibration-transmitting structure, the vibrator including a piston slidably disposed in a cylinder defined in a housing, the piston associated with a strike surface and a selective adjustment mechanism associated with the housing which can be used to eliminate slack between the strike surface of the vibrator and the rapping rod and which can be further used to externally adjust the pre-load on the rapping rod and to align the vibrator axially with the rod and to compensate for thermal expansion and contraction.

Abstract: A pneumatic impact tool wherein a two-stage piston is reciprocable in the two-stage chamber of a cylinder. The tool which is to penetrate into a bone is mounted in the front portion of the cylinder and the piston strikes against such front portion in response to admission of compressed air against its rear end face. A relatively small annular shoulder of the piston faces forwardly and is continuously acted upon by compressed air. When the piston approaches or reaches the end of its forward stroke and rebounds from the front end portion of the cylinder, it seals the source of compressed air from its rear end face so that the action of compressed air upon the shoulder suffices to propel the piston rearwardly against the rear end portion of the cylinder at which time the piston reestablishes a path for the flow of compressed air against its rear end face so that it is propelled forwardly against the front end portion of the cylinder.

Abstract: A powered impact instrument comprising a spring-loaded head mounted at one end of a housing; a spring-loaded striker mounted within the housing; a block which slides reciprocally within the housing to which the striker is attached; a drive for the block which draws the block toward the rear of the housing; a sear which releasably couples the block to the drive to permit the block to draw the striker back against its spring, and which releases the block at a selected point of each stroke of the block so that the spring drives the striker against the head in order that the head may provide a high impacting force on the object being impacted thereby. An adjustable trigger is also provided by which the displacement of each stroke of the striker, and thus the impact by which it strikes the head, may be controlled. A unique coupler releasably attaches different tools to the head.

Abstract: A drill chuck is secured on a drill spindle so as to be actuated thereby. The drill chuck has an axial passage through which the impact effect of a central anvil shaft is transferred to the end of the drill held in the drill chuck. The drill chuck can be connected to the drill spindle by coupling elements respectively arranged in coupling retainers of the drill spindle and/or the chuck body. The coupling retainers are axially of greater longitudinal dimension than the coupling elements, and permit axial displacement of the drill chuck. A contact ring which can not be displaced in axial direction presents an annular surface towards a further annular surface at the drill chuck body. Abutment projections can preclude axial displacement of the drill chuck on the drill spindle, and associated abutment recesses are also provided into which the abutment projections fit at least to a depth equivalent to the axial displacement movement of the drill chuck.

Abstract: A method and apparatus for guiding a body into the ground by means of a single hammer acted on by a reaction mass which is driven by a double-acting piston-cylinder unit via a controlled, periodically changing stream of pressure medium and which generates forces which act on the body in its longitudinal direction, the body being driven by first causing the pressure stream to have an approximately sinusoidally pulsating form for imparting a vibratory movement to the hammer, and then, when the speed with which the body is being driven into the ground decreases below a given minimum value, causing the pressure medium to drive the reaction mass according to a periodic, approximately unsteady displacement-time function for imparting a hammering movement to the hammer, while, during such hammering movement, simultaneously monitoring the hammering energy being generated.

Abstract: A fastener driving tool includes a housing defining a handle portion and a head portion with a nose portion extending therebelow. Mounted within the head portion is a cylindrical sleeve within which is reciprocally mounted a drive piston. A driver for driving fasteners is secured to the drive piston and reciprocates therewith. The tool includes a drive power control for controlling the penetration of the fasteners into a workpiece. The drive power control includes a choke encircling the sleeve to impede the flow of exhaust air from beneath the piston and under the sleeve during a driving stroke. The choke may be moved to a position spaced from the cylindrical sleeve wherein the flow of fluid below the piston is not inhibited. In addition, the tool includes a safety member with a workpiece engaging portion of at least one wear block secured thereto to engage the workpiece and protect the safety member from undue wear.

Abstract: There is disclosed an impact applying mechanism, particularly as applied in a subterranean drilling apparatus, and comprising a cylinder (13) arranged with its axis substantially vertical and connected to the member to which impact is to be applied, a piston (5) slidably mounted within the cylinder (13), means to admit pressure fluid to the cylinder (13) below the piston (5), at least one valve tube (24), slidably mounted in the base of the cylinder (13), coil springs (30) to bias the upper end of the valve tubes (24) into sealing engagement with the underside of the piston (5) when the piston is in its lowest position, a flange (26) on the upper end of the valve tubes (24) upon which fluid pressure in the cylinder (13) acts to produce a force urging the end of the valve tubes (24) into contact with the underside of the piston (5), and further coil springs (32) to provide a force to said valve tubes (24) of a magnitude which increases as the piston (5) moves upwardly relative to the cylinder (13) to subsequen

Abstract: A tool is disclosed which has a variable tool stroke useful for inserting a wire conductor into and along a conductor terminating slot of an electrical terminal of the type disclosed in U.S. Pat. No. 4,141,618.

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 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: Switch means on the frame of a forging device senses when the ram and piston enter a first zone of a pneumatic cushion during retraction to initiate timing. If a predetermined time has expired before the ram leaves the first zone, the fluid inlet valve is opened. If not, switch means senses when the ram and piston enter a second zone to initiate a second timing. If a second predetermined time expires before the ram leaves the second zone, the fluid inlet valve is opened. If not, switch means senses when the ram and piston enter a third zone, and after a predetermined time the fluid inlet valve is opened. Thus, by sensing ram position and measuring time ram remains within each zone, the effective upward velocity (distance/time) is measured and adaptive controls applied.

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: A portable hydraulic actuated machine for driving posts, ground anchors, concrete breakers, core drills and the like work pieces into the ground, pavements, or wall structures, maintains a continuing thrust on the work piece amplified by sequential hammer blows of controlled magnitude to advance the work piece at a rapid rate without damage to the impact receiving end of the work piece. The machine includes an automotive vehicle which is easily transported to the work site and which carries a turntable supporting an upstanding tower on which rides a carriage slidably mounting a spring loaded heavy hammer, a work piece engaging spring loaded anvil struck by the hammer and hydraulical hammer lifting mechanism. The tower is easily raised and lowered, adjusted toward and away from the vehicle and tiltable laterally to present the hammer and anvil to the work piece at the exact desired location in the plane of the work piece.

Abstract: A rock drilling apparatus comprises a hydraulically rotated drill, a percussion motor having a piston which transfers impact energy to the drill, the piston defining together with the machine housing first and second pressure chambers for receiving pressure liquid to move the piston, the percussion motor having a hydraulic circuit including a high pressure side and a low pressure side, a pressure liquid distributing valve having a control input for receiving a control pressure, the distributing valve being located in the hydraulic circuit of the percussion motor for alternately connecting at least one of the pressure chambers to the high pressure side and low pressure side, respectively, of the hydraulic circuit in response to the control pressure, the hydraulic circuit for rotating the drill being separate from the hydraulic circuit of the percussion motor and including a high pressure side and a low pressure side separate from the high and low pressure sides of the percussion motor, a control valve for cont

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.

Abstract: A drill housing is pivotally connected to the forward end portion of a boom member that swings upwardly from a frame of a mobile drilling machine. A hydraulic motor is secured to the gear housing and provides rotary power from a drive shaft through a pair of meshing gears to a drill chuck that is arranged to receive a drill bit or a roof bolt. A percussion weight is concentrically positioned within the drill housing and is axially aligned with the drill bit for imparting percussive forces to the drill bit. The percussion control is maintained through a servovalve that is supported on the drill housing and is controlled remotely by an electronic control module. The servovalve controls the flow of pressurized fluid from a source through ports in the drill housing connected to the servovalve by conduits to actuate a piston member for oscillation within the drill housing. Oscillation of the piston imparts a percussive force upon the percussion weight which is transmitted to the drill bit.