Abstract: A hydraulic, pneumatic, gasoline, diesel, or electric tool may include a spindle that is adapted for rotational movement. A swing arm may be coupled to the spindle such that rotational motion of the spindle is transferred to the swing arm. The swing arm makes contact with a piston such that the rotational motion causes the piston to move along a linear path. The piston may interact with an energy storage medium when the swing arm moves the piston in the first direction, causing energy to be stored in the energy storage medium. As the swing arm continues to rotate, the swing arm may lose contact with the piston, thus allowing the energy storage medium to urge the piston in a second direction opposite the first direction to strike an anvil. The swing arm may be a multiple roller swing arm. The energy storage medium may be a compound spring assembly.

Abstract: A portable linear fastener driving tool is provided that drive staples, nails, or other linearly driven fasteners. The tool uses a gas spring principle, in which a cylinder filled with compressed gas is used to quickly force a piston through a driving stroke movement, while a driver also drives a fastener into a workpiece. The piston/driver is then moved back to its starting position by use of a rotary-to-linear lifter, and the piston again compresses the gas above the piston, thereby preparing the tool for another driving stroke. The driver has protrusions along its edges that contact the lifter, which lifts the driver during a return stroke. A pivotable latch is controlled to move into either an interfering position or a non-interfering position with respect to the driver protrusions, and acts as a safety device, by preventing the driver from making a full driving stroke at an improper time.

Abstract: A pneumatic fastener driving tool includes a gas cylinder, and a piston disposed in the cylinder in such a way that a centerline of the piston is coaxial with the cylinder longitudinal axis, and the piston is movable along the cylinder longitudinal axis between ready and driven positions. The tool includes a blade having a blade first end that is connected to the piston, and a blade second end that is configured to contact a fastener during a fastener driving operation. The tool includes a reset mechanism that returns the tool to the ready to fire configuration by translating the piston along the cylinder longitudinal axis to a location in which gas is compressed in the cylinder. The reset mechanism includes a ball screw device that drives the piston toward the ready position via a force that is concentric with the centerline of the piston.

Abstract: There is provided a driving machine capable of reducing a load applied to a guide member in a direction of a center axis. The driving machine drives a fastener into a workpiece. The driving machine includes a movable piston, a driver blade operating together with the piston and applying driving force to the fastener, a cylinder guiding operation of the piston, a holder provided in a housing and supporting the cylinder, and a vibration damping rubber interposed between the holder and the housing and receiving a load applied to the holder in an operational direction of the piston.

Abstract: There is provided a driving machine capable of reducing a load applied to a guide member in a direction of a center axis. The driving machine drives a fastener into a workpiece. The driving machine includes a movable piston, a driver blade operating together with the piston and applying driving force to the fastener, a cylinder guiding operation of the piston, a holder provided in a housing and supporting the cylinder, and a vibration damping rubber interposed between the holder and the housing and receiving a load applied to the holder in an operational direction of the piston.

Abstract: A fastener driver comprises a driver blade movable from a retracted position to a driven position and a lifter assembly for moving the driver blade from the driven position toward the retracted position. The fastener driver also includes a first sensor to detect the driver blade in the driven position, a latch which, in a locked position, maintains the lifter assembly in an engaged position, an actuator coupled to the latch for moving the latch between the locked position and a released position, in which the lifter assembly may move away from the driver blade, and a controller electrically connected with the first sensor and the actuator. In response to an absence of a signal from the first sensor after a predetermined time following initiation of a fastener driving operation, the controller triggers the actuator to move the latch from the locked position to the released position.

Abstract: A return device includes a return wheel unit adapted to be mounted to a gun body of a fastening tool, and including a return wheel that is movable between a free position, where the return wheel is not in contact with an impact member of the fastening tool, and a return position, where the impact member is at a strike position and is not contact with a rotatable flywheel of the fastening tool, and where the return wheel is in contact with the flywheel and the impact member such that, when the flywheel rotates in a first rotational direction, the return wheel is driven by the flywheel to rotate in a second rotational direction opposite to the first rotational direction, and moves the impact member from the strike position to a standby position.

Abstract: An orthopedic impacting tool includes a motor-based drive assembly, an air chamber, a compression piston, an impacting element, an anvil element, and a broach adapter. The anvil element may include first and second faces and may be adapted to accept a portion of the broach adapter such that the broach adapter is proximate to the first face and distal to the second face. In operation, the motor-based drive assembly may cause the compression piston to move and compress air in a first portion of the air chamber or in a second portion of the air chamber. The impacting element may cyclically impact the first face of the anvil element upon application of compressed air from one of the first and second portions, and cyclically impact the second face of the anvil element upon application of compressed air from the other of the first and second portions.

Abstract: A driving tool having first and second linear motors, a head assembly, a nosepiece and a driver. The first linear motor forms an air compressor and includes a scotch yoke mechanism for translating a first piston in a first cylinder. The scotch yoke mechanism includes a crank arm, a crank arm roller, which is coupled to the crank arm, and a connecting rod having a roller slot into which the crank arm roller is received. At least a portion of the roller slot is configured to vary an output rate at which the connecting rod translates along a translation axis relative to an input rate at which the crank arm roller moves in a direction that is parallel to the translation axis.

Abstract: The invention concerns a driving tool comprising a motor, in particular, an electric motor, a gas spring with an elastically compressible gas volume, and a firing piston, wherein the gas spring can be tensioned via a tensioning device with the motor, so as to accelerate after a release from a tensioned state the firing piston in a firing direction, wherein at least one part of the tensioning device is located within the gas volume of the gas spring.

Abstract: An impact system for a hydraulic hammer is disclosed. The impact system may include a piston, a sleeve disposed co-axial with the piston, and an accumulator membrane disposed external to the sleeve. A first seal may be located at an end of the sleeve, and configured to connect the sleeve to the piston. The accumulator membrane may have an extension configured to engage a recess in the sleeve.

Abstract: A hammer drill includes, in a cylinder accommodated in a housing, a piston configured to advance and retract and an impact element to operate together with the piston with an air chamber interposed therebetween, and a bit mounted in a front part of a tool main body so that an impact operation can be transmitted to the bit by advancing and retracting movement of the impact element. Vent holes are provided in the cylinder, and configured to discharge air in the air chamber to outside of the cylinder, and to introduce the air outside the cylinder into the air chamber by the movement of the piston. One of the vent holes is located at a center of an upper half of a periphery of the cylinder and the other vent hole is located in a lower half of the periphery of the cylinder.

Abstract: Hammering device functioning with pressure fluid of a hydraulic arrangement which hammering device comprises a body (16), (19) which can be attached to a working machine on which machine a hammering mass (3) is adjusted to be resting and to be moving which hammering mass is moved into a hammering position with the help of hydraulic pressure by directing the pressurized fluid into the ring-shaped, first chamber space (6) wherein the hammering mass (3) when it is moving into a hammering position compresses gas in the chamber space (K1) located at the first side of the hammering mass (3) and in order to perform the hammering movement with the hammering mass (3) to the hammering element (5), (27) the flow of hydraulic pressure is blocked to the first chamber space (6) and the access for pressure fluid is allowed away from the first chamber space (6) with the help of the valve (2).

Abstract: A pile driving system for driving a pile. The pile driving system comprises a housing assembly, a hammer, a helmet member, and a lifting system. The housing assembly defines at least one vent opening is arranged at a first vent location along the drive axis, and at least one vent opening is arranged at a second vent location along the drive axis. When the hammer drops and is above the first vent location, ambient air flows from the main chamber through the vent openings formed at the first and second vent locations. When the hammer is below the first vent location and above the second vent location, ambient air flows from the main chamber through the vent openings formed at the second vent location. When the hammer is below the second vent location, air within the main chamber is compressed to preload the helmet member.

Abstract: A hammer drill having a motor mounted within a body and an output spindle; a tool holder mounted on the body capable of holding a cutting tool; a hammer mechanism having a piston; a reciprocating drive for converting rotary movement of the motor into reciprocating movement of the piston; a ram reciprocatingly driven by the piston via an air spring to strike a cutting tool held in the tool holder, the hammer mechanism performing one hammer cycle each time the ram strikes a cutting tool during normal use; an air replenishment mechanism capable of refreshing the air spring during certain time periods during normal use; the air replenishment mechanism capable of being adjusted to refresh the air spring during time periods within the hammer cycle and/or the system allows different volumes of air into or out of the air spring during the refreshment time periods.

Abstract: A hammer drill including a cylinder; a piston and a ram mounted within the cylinder; a drive mechanism for converting rotation of a motor into reciprocating movement of the piston; a ram driven by the piston via an air spring; at least two air entry points formed through the wall of the cylinder in different axial positions along the length of the cylinder, each of which are capable of replenishing the air spring; the ram striking a tool in a tool holder; wherein there is further provided a selector mechanism which selectively opens and close the air entry points; characterized in that the selector mechanism opens only one air entry point at any one time during normal use, the selector mechanism closing all other air entry points, each of the air entry point capable of replenishing the air spring during normal use when opened by the selector mechanism.

Abstract: A fluid powered percussion tool 1 has a housing 2 with a supply channel for pressurized fluid 3, a percussion mechanism 4, a swing joint 5 arranged to carry the percussion mechanism 4 relative to the housing 2 at a point situated between the forward end A and the rear end B of the percussion mechanism 4, at least one elastically resilient element 6 arranged between the housing 2 and the percussion mechanism 4 at a distance from the swinging joint 5 and arranged to load the percussion mechanism 4 against a neutral position in the housing 2 and to absorb the vibrational movements of the percussion mechanism 4, and a flexible connection for pressurized fluid 7 for distribution of pressurized fluid from the supply channel for pressurized fluid 3 to the percussion mechanism 4. The elastically resilient element 6 includes a conical spring 8. The flexible connection for pressurized fluid 7 includes a hose 11.

Abstract: A percussive mechanism, which is provided in the form of an, e.g. pneumatic spring percussive mechanism, comprises an electrodynamic linear drive, a drive piston, which can be reciprocally moved inside a percussive mechanism housing by the linear drive, and a percussive piston. An additional hollow space is provided in front of and/or behind the drive piston and can be isolated at least in part from the surrounding area so that a pneumatic spring can be created in the additional hollow space. The pneumatic spring slows the drive piston at its returning points and facilitates a returning motion without loading the electrodynamic linear drive.

Abstract: A pressure fluid operated impact device comprising a frame (2) whereto a tool (3) is mountable movably in its longitudinal direction, and control means (7) for controlling pressure fluid feed to the impact device (1), as well as a method of generating a stress pulse in a pressure fluid operated impact device. The impact device (1) comprises a working chamber (8) and a transmission piston (9) moving therein. Energy charging means for charging energy of pressure fluid and the control means are coupled to allow periodically alternately pressure fluid to flow to the working chamber (8) and, correspondingly, to discharge pressure fluid from the working chamber (8). In the method, pressure fluid is fed to the working chamber (8), which produces a force pushing the transmission piston (9) in the direction of the tool (3), thus generating a stress pulse in the tool (3).

Abstract: A shock-absorbing element is disposed frontward of an interjacent element within a housing of an impact tool, and a washer is disposed rearward of and adjacent to the shock-absorbing element. The interjacent element is configured to come in contact with the washer when the interjacent element is caused to advance by an impactor's strike under no-load conditions. A sleeve disposed rearward of and adjacent to the washer is configured to position the shock-absorbing element and the washer, and to allow the interjacent element to move rearward and frontward inside the sleeve.

Abstract: The invention relates to a method for breaking rock to be drilled in rock drilling, in which method the rock to be drilled is subjected to successive stress pulses via a tool. The method comprises stress pulses being exerted on the rock at a high frequency, and the load proportion calculated on the basis of the values of the frequency and the length (tp) of the stress wave being at least 0.075.

Abstract: A pressure-fluid-operated percussion device includes a frame allowing a tool to be arranged movably in its longitudinal direction. Pressure liquid is fed to the percussion device and returned to a pressure liquid tank. A stress pulse is produced in the tool utilizing pressure of the pressure liquid. A pressure liquid source maintains pressure in the working pressure chamber. Pressure liquid is intermittently fed to the percussion device such that the pressure liquid pushes a transmission piston into a predetermined backward position. Pressure liquid is alternately discharged rapidly from the percussion device so that the pressure of the pressure liquid in the working pressure chamber and the pressure liquid flowing from the pressure liquid source pushes the transmission piston towards the tool, generating a stress pulse in the tool.

Abstract: An impact tool for simultaneously providing a rotational force and an impact force to an object has an output shaft rotated by a motor, hammer for intermittently providing an impact force to the output shaft, hammer holder for movably holding the hammer, and an impact force generator for generating the impact force from an output of the motor. An air chamber is formed between the hammer and the hammer holder such that a volume of the air chamber is variable in response to a position of the hammer relative to the hammer holder. In addition, the hammer receives a bias force generated in a direction toward the output shaft by a biasing device. This bias force effectively increases the impact force in cooperation with an air pressure caused by a volume change of the air chamber.

Abstract: An impact force is transmitted to a tip end tool due to the changes of the air pressure within an air chamber generated by the reciprocal operation of the piston within a striker. The attachment portion of a tip end tool holding member for holding the tip end tool to a cylinder casing is sandwiched between buffers disposed in the two directions of the axial direction of the tool thereby to elastically support the tip end tool holding member to be movable in the two directions of the axial direction of the tool.

Abstract: A hand-held power tool includes a pneumatic percussion mechanism (20) having a driving member (22) reciprocating in the guide tube (21), a percussion member (23) driven by the driving member (22), and an air spring (24) located between the driving member (22) and the percussion member (23) transmits a reciprocating movement of the driving member (22) to the percussion member (23), The hand-held power tool further includes a motor-driven elongate swashplate member (29) for reciprocating the driving member (22) a displacement stroke of which is adjusted by an adjusting member (31) displaceable along a longitudinal extent of a swashplate member (29) for adjusting a swashplate angle that determines the displacement stroke of the driving member (22).

Abstract: A driving mechanism for a powered hammer having a motor and a tool holder includes a ram mounted for reciprocation in a guide tube section. The ram has a radially outwardly projecting sealing portion and an outer circumferential surface that defines a helically shaped vent channel running from a front end portion of the circumferential surface to a rear end portion of the circumferential surface and being interrupted by the sealing portion. A piston is driven in reciprocating motion of the motor such that an air cushion is generated in a space between the ram and the piston to cause an impact on the tool bit by movement of the ram towards the tool bit. The space between the ram and the piston is temporarily connected with ambient air through the helical vent channel and a recess in the wall of the guide tube section after causing the impact on the tool bit.

Abstract: An exemplary embodiment of the jet hammer includes an outer sleeve, impact assembly, and a valve assembly. The impact assembly is positioned in sliding relation to the outer sleeve to provide the impact of the jet hammer. The valve assembly generally comprises a cap screw, adjustment sleeve, valve port, inner compression spring, outer compression spring, and lock nut. The inner compression spring is relatively less compressible than the outer compression spring. In operation, fluid enters the valve assembly and acts on the compression springs forming an operational seal between the valve assembly and the impact assembly. In response, the outer sleeve is slidingly displaced from the impact assembly thereby compressing a main compression spring positioned along the mandrel shaft. Once the pressure acting on the valve assembly is released, the main compression spring decompresses forcefully causing the outer sleeve to impact a connection port, bit, tool, or other member attached to the upper end of the mandrel.

Abstract: A pneumatic percussion mechanism for a hand-held power tool includes a percussion piston (23) displaceable in a guide tube (21) for applying impacts to an anvil (24), a driving member (22) reciprocating in the guide tube (21) for driving the percussion piston, and an air spring (25) for transmitting a driving torque from the driving member (22) to the percussion piston (23) and directly switchable on and off by the anvil (24).

Abstract: A hand-held power tool includes a pneumatic percussion mechanism having a percussion piston reciprocating along a percussion axis and having a bore extending at an angle to the percussion axis, and an air spring for displacing the percussion piston.

Abstract: A hand-held power tool (1) includes a linear motor (2) having a rotor (3) which is movable along a percussion axis (A) in an axially limited manner between two reversal points (W) and which can be driven by the striking piston (5) of the power tool with the intermediary of an air spring (4), sensors designed for determining the actual state of the rotor (3) and connected to a computer (9) connected via power electronics (33) to at least one field coil (10) of the linear motor (2), with the rotor (3) being displaced against a contact element (11a, 11b) at least at one reversal point (W) and being pressed against the contact element electromagnetically; and a control process for the hand-held power tool.

Abstract: A hand-held power tool includes a pneumatic percussion mechanism (20) having a driving member (22) reciprocating in the guide tube (21), a percussion member (23) driven by the driving member (22), and an air spring (24) located between the driving member (22) and the percussion member (23) for transmitting a reciprocating movement of the driving member (22) to the percussion member (23), and a motor-driven elongate swashplate member (29) for reciprocating the driving member (22) a displacement stroke of which is adjusted by an adjusting member (31) displaceable along a longitudinal extent of a swashplate member (29) for steplessly adjusting a swashplate angle that determines the displacement stroke of the driving member (22).

Abstract: A driving mechanism for a powered hammer having a motor and a tool holder includes a ram mounted for reciprocation in a guide tube section. The ram has a radially outwardly projecting sealing portion and an outer circumferential surface that defines a helically shaped vent channel running from a front end portion of the circumferential surface to a rear end portion of the circumferential surface and being interrupted by the sealing portion. A piston is driven in reciprocating motion of the motor such that an air cushion is generated in a space between the ram and the piston to cause an impact on the tool bit by movement of the ram towards the tool bit. The space between the ram and the piston is temporarily connected with ambient air through the helical vent channel and a recess in the wall of the guide tube section after causing the impact on the tool bit.

Abstract: A percussion device for a rock drilling machine or the like, which includes providing an impact, i.e. a stress pulse, to a tool connected to the percussion device. The the stress pulse is provided by way of a stress element of liquid, which is supported to a body of the percussion device. The stress element is subjected to pressure and correspondingly the stress element is released abruptly, whereby the stress energy is discharged as a stress pulse to the tool in direct or indirect contact with the stress element.

Abstract: An impact device includes a frame to which a tool is connectible, and a stress element that is supported on the frame and disposed between the frame and the tool. A hydraulic control system leads pressurized hydraulic fluid into and out of a hydraulic fluid space such that the stress element causes a stress pulse in the tool. The hydraulic control system includes a rotatingly installed control valve that has control openings for intermittently leading the hydraulic fluid out from the hydraulic fluid space.

Abstract: A percussion device for a rock drilling machine or the like, which comprises means for providing an impact, i.e. a stress pulse, to a tool connected to the percussion device. The means for proving the stress pulse include a stress element (4) of liquid, which is supported to a body (2) of the percussion device and means for subjecting the stress element to pressure and correspondingly for releasing the stress element (4) abruptly, whereby the stress energy is discharged as a stress pulse to the tool in direct or indirect contact with the stress element.

Abstract: A percussion power tool assembly (10) comprises a hand-held percussion power tool (11), a chamber (12) mounted on the tool (11), and a fluid reservoir (14) supported independently of the tool (11). The percussion power tool (11) has a body (20) housing a reciprocating hammer (22) which impacts against tool bit (24) in a conventional manner. The hammer (22) is operated by compressed air admitted though valve (26) in feed line (28). The chamber (12) communicates with the fluid reservoir (14) though flexible hose (16). The chamber (12) surrounds the body (20) and has a flexible lining (30) defining a bladder which inflates/deflates in sympathy with fluid filling, or emptying from, the chamber. The deadweight of the hand-held part (18) of the assembly (that is, the tool and chamber combined) is varied by transferring fluid, e.g. water, in the reservoir (14) to the chamber (12), and reduced by returning transferred fluid to the reservoir (14).

Abstract: A hydraulic impact tool for use in a well, such as an oil or gas well, comprising a movable hammer which is arranged to prestress a spring by means of a hydraulic piston (16) provided with a through channel (20), and in which a movable sealing body (22, 45) is arranged to enable closing of the channel (43), so that hydraulic force from fluid under pressure applied to the impact tool, may displace the piston (16) and the hammer and prestress the spring, and in which the sealing body (22) is arranged to follow the piston (16) into an end position for so to open the channel (20) for throughput, so that the hydraulic force acting on the piston (16, 41) ceases, and the prestressed spring is released and drives the hammer to strike, at the same time as the piston (16, 41) returns to initial piston, whereafter the process is repeated. The sealing body (22) is arranged to close said channel (20) when the sealing body is subjected to a predetemined frictional force from fluid flowing through the impact tool.

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: A compressed-air-operated percussion mechanism includes a housing, a percussion body and a balancing body, which form an operating chamber therebetween. A secondary valve seals the operating chamber during an operating stroke and opens the chamber to evacuate compressed air after the termination of the operating stroke. A primary valve is connected to the compressed air inlet passage and intermittently opens to provide compressed air to the operating chamber.

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: An improvement to a delimber system having a delimbing unit including cutting elements, for cutting limbs extending from a tree trunk, and a tree trunk loader mechanism, for pulling the tree trunk of a tree to be delimbed through the delimbing unit such that the limbs extending from the tree trunk are severed from the tree trunk by the cutting elements. The improvement includes adding a base frame; a slide carriage mounted between the base frame and the delimbing unit such that the delimbing unit is slidable with respect to the base frame between a forward delimber position toward the tree trunk loader mechanism and a rearward delimber position away from the tree trunk loader mechanism; and an impact assembly mounted functionally between the base frame and the delimbing unit, the impact assembly including a force generating mechanism for generating a force transmitted between the base frame and the delimber unit to force the delimber unit into the rearward delimber position.

Abstract: Pressure fluid operated impact mechanism having a reciprocating working member (5), a stop member (17) and, formed between said members, a drive chamber (18) with seals (15, 16) and a regulating valve (21) co-operating with a supply opening (25) for pressure fluid, in which opening a sleeve (24) can be arranged for the journalling of the valve. The valve blocks the opening when the working member (5) and the stop member (17) have moved a distance away from each other and is open when they are close to each other. Through the valve and the working member, a discharge channel (33, 31, 20, 32) for pressure fluid is provided which is closed when its inlet opening (33) is inside the stop member and is freed when the working and stop members have moved a distance away from each other.

Abstract: A hydraulically driven hammer has a piston which contains metal piston rings on a constant diameter section. The housing has a plurality of axially spaced apart radial ports that extend through the housing into the bore. A valve supplies fluid to the ports to control reciprocation of the piston.

Abstract: A pressure medium operated reciprocating impact mechanism has at least one working member (7) and at least one stop member (15), which are axially movable with respect to each other, and a working chamber (22) for pressure medium is arranged in at least one of them and is opened towards the other member. One of the members has an opening (39) emerging into the working chamber for feeding pressure medium to the working chamber. The impact mechanism comprises an arrangement (21) for sealing the working chamber in the position in which the members are brought most together and allow pressure medium to escape out of the working chamber when a predetermined relative position of the members is reached during their movement apart.

Abstract: An apparatus for generating impacts which has a hydraulic cylinder and a reciprocating piston. The hydraulic cylinder has an impact chamber, a cavity which receives and diverts fluid, and a throat which connects the impact chamber with the cavity. When the pressure line is connected to the cavity, the piston is lifted to an upper position. When the overflow line is connected to the cavity, the piston drops down such that the piston enters and covers the throat at the impact chamber. The pressure in the chamber remains low as the chamber is sealed by the piston entering the throat, where the energy loss is insignificant. The piston enters into the throat such that it is stopped and presses against the fluid inside the impact chamber, and thereby generates an impact therein. The piston is lifted up to repeat the cycle, when the cavity is connected to the pressure line.

Abstract: Apparatus comprising a striking piston driven hydraulically in a reciprocating fashion by an incompressible fluid inside a cylinder and striking against a tool, of the type in which the piston slides in a cylinder having two concentric piston bearing surfaces of different sections, of which that situated on the tool side has a section smaller than that remote from the tool, the piston and the cylinder delimiting two antagonistic chambers, an annular bottom chamber and a top chamber of larger section.According to the invention the interior of the top chamber is permanently at a regulated pressure of a value intermediate between the inlet or high pressure and the outlet or low pressure, and the annular bottom chamber is connected alternately by a distributor to the high pressure supply circuit during the upward phase of the piston and to the top chamber during the accelerated downward phase of the piston.

Abstract: A drill or impact hammer has a mechanical striking mechanism which is driven in a reciprocating manner by a drive element which is tiltable around an axle. A resilient driver member which is tiltable around the axle serves to transmit this movement to a striker. The driver member is articulated at the striker with play to protect the bearings from the reaction forces in percussion operation.

Abstract: A pneumatic downhole impact drill having a porting system for automatically supplying pneumatic pressure fluid from a fluid delivery tube received within a coaxial bore in the impact piston to the opposite ends of the piston operating cylinder as the piston reciprocates. The porting system comprises an annular set of equiangularly spaced outlet ports in the fluid delivery tube and two sets of radially extending bores in the piston having first and second, axially spaced, annular sets of equiangularly spaced inlet ports which cooperate with the outlet ports in the delivery tube. The number of inlet ports in the piston in each set thereof, is different than the number of outlet ports in the supply tube and the combined angular widths of the ports of each set of inlet ports and the outlet ports is substantially greater than 360.degree. to provide substantial fluid communication therebetween at all relative angular positions of the piston and fluid delivery tube.