Abstract: A method for reducing vibrations in a percussion tool includes activating, using an electronic controller of the percussion tool, the motor of the percussion tool, determining, using the electronic controller, that the percussion tool is in a loaded condition, and operating, using the electronic controller, the motor in accordance with a predetermined profile in response to determining that the percussion tool is in the loaded condition. The method also includes determining, using the electronic controller, that the percussion tool is in a no-load condition and operating, using the electronic controller, the motor with reduced speed in response to determining that the percussion tool is in the no-load condition.

Abstract: A snow stake driver that allows for fast, safe, and convenient placement of snow stakes at controlled and/or predetermined depths in soil with aggregate and/or rocks, including: a body, wherein the body is elongated and includes a first end and a second end; a handle member, wherein the handle member is positioned proximate to the first end of the body; a depth setting plate, wherein the depth setting plate is positioned proximate to the second end of the body; and a ground-engaging drive rod.

Abstract: A percussion tool comprises a housing and an electric motor positioned within the housing. The percussion tool further comprises a battery pack supported by the housing for providing power to the motor. The battery pack includes a plurality of battery cells having a nominal voltage of up to 120 Volts. The percussion tool further comprises a percussion mechanism driven by the motor and including a striker supported for reciprocation in the housing. The percussion tool has a ratio of impact energy to mass that is greater than or equal to 2.5 Joules/kilogram.

Abstract: A dust suppression system for a demolition hammer is disclosed. The dust suppression system may have a water hose routed within a power cell of the demolition hammer, and a connector channel internal of the walls of a front head of the demolition hammer. The water hose may be utilized to deliver water from outside of the demolition hammer to a connection valve on a top end of the front head, and the internal connector channel may deliver water from the connection valve to one or more nozzles located at a bottom end of the front head.

Abstract: A ground drilling device comprising a housing, a lengthwise movable drilling head tip arranged in the housing, and a bearing for supporting the drilling head tip in the housing during its lengthwise movement.

Abstract: A ground drilling device with a percussion piston for drilling into the soil, comprising at least one housing section for the percussion piston, wherein an insert is arranged in the housing between the drilling head tip and the percussion piston such that the insert transmits at least a portion of the energy of the percussion piston to the housing, and the insert is held in the housing by means of a shrinking adhesion connection.

Abstract: A method employing an apparatus in conjunction with a hammer-drill to penetrate composite metal and non-metal structure or structures including, for example, thick metal or rebar encountered during concrete, rock or masonry boring operations without requiring a change in drill equipment.

Abstract: Damping device for a percussion device of a hydraulic rock drilling machine (1) with a striking direction (R), including a damping piston (5) for action in an axial direction against a tool, wherein the damping piston (5) exhibits a first piston portion (6), which is received in a first damping chamber (7) and a second piston portion (8), which is received in a second damping chamber (9). In operation, in a normal striking position of said percussion device, the damping piston (5) is set against a fixed stop (19) against movements in the striking direction. A damping slot (10) is established between the first (7) and the second (9) damping chamber in all axial positions of the damping pistons, and the first damping chamber (7) is pressurized with a hydraulic pressure. The invention also concerns a percussion device and a rock drilling machine.

Abstract: A hammer including a housing and a piston arranged for reciprocating movement within the housing is disclosed. The hammer further includes a head assembled on the housing and defining a chamber for holding a pressurized gas and a wall configured to abut the housing and defining a gas discharge passage extending between the chamber and the housing. A plug is positioned in the gas discharge passage and configured to move or deform under pressure of the pressurized gas in the chamber.

Abstract: A quick release down-the-hole (DTH) hammer drill bit assembly includes a drill bit releaseably retained at a drive transmission component (drive sub) via a retaining sleeve and respective retaining formations to axially couple and lock the drill bit at the assembly. In particular, the drill bit is retained exclusively at the assembly via retaining formations at the drive sub, the sleeve and the drill bit, without a requirement for additional retaining rings that would otherwise axially lock the drill bit at the drive sub.

Abstract: Percussion unit, especially for a rotary hammer and/or percussion hammer, comprising a control unit which is designed for open-loop and/or closed loop control of a pneumatic percussion mechanism, and at least one operating condition sensor unit. According to the disclosure, the control unit is designed to detect at least one percussion mechanism parameter depending on measurement values of the operating condition sensor unit.

Abstract: A cushion device is used for a cylinder of a pneumatic tool, and the pneumatic tool contains: a body, a cylinder, a valve unit, a piston member, and a cushion washer. The body includes a grip and a fitting sleeve having a chamber, a closing face, and an opening. The cylinder is slidably fitted in the chamber, partially extends out of the fitting sleeve from the opening, and includes a room and an abutting portion. The valve unit is mounted between the room and the abutting portion. The piston member is accommodated in the room and slides along a movement axis. The cushion washer is made of a flexible rubber, is mounted in the chamber, and abuts against the closing face and the pressing face. The cushion washer includes at least one open segment which has at least one air groove each having a mouth parallel to the movement axis.

Abstract: An improved pile hammer provides a cylinder, such as one with a uniform interior diameter wall and uses a piston ram to cycle up and down therein to contact an anvil on a downstroke. The anvil preferably provides a cavity to both lessen the weight and improve upward force on the ram for the upstroke. An air inlet is preferably located above an air outlet which was not possible with prior art designs. An air reservoir can be located above and external to the wall in the cylinder.

Abstract: A telebending tool for conveying a logging tool into a wellbore includes a tool body having a central axis. In addition, the tool also includes a cam housing coupled to the tool body and a nose moveably coupled to the tool body through a pivoting member. Further, the telebending tool includes a compression spring positioned between the nose and the pivoting member, and a camming arm coupled to the nose. The camming arm extends coaxially through the pivoting member to selectively engage a cam pathway of the cam housing. The nose has a first position with a central axis of the nose coaxially aligned with the central axis of the body and a second position with the central axis of the nose oriented at an angle less than 180° relative to the central axis of the body.

Abstract: A percussion drilling assembly includes a housing with a hammer bit disposed in the lower end portion thereof and configured to move longitudinally within the housing. The hammer bit includes an annular bit shank having a bit strike face and a cutting structure at a lower end portion thereof. An annular piston having a piston strike face arranged and designed to strike the bit strike face is also disposed in the housing. At least one of the bit strike face and the piston strike face has a toroidal curvature profile. A method includes one or more of lowering the percussion drilling assembly into a borehole, engaging the cutting structure with a formation, and impacting the bit strike face of the annular bit shank with the piston strike face of the annular piston.

Abstract: A pneumatic post driving apparatus comprises an internal cylinder chamber within which a hammer piston is reciprocated. The hammer piston strikes against an anvil, which in use is abutted against the top of a post to be driven. Kinetic energy from the descending hammer piston is transferred through the anvil into driving energy for the post. An air control system alternately routes pressurized air between the top and bottom ends of the cylinder to move the hammer piston up and down. The air control system includes a spool-type control valve disposed for sliding movement within a control body. The anvil is resiliently suspended at the bottom of the cylinder chamber by an annular retention flange that has a conically tapered under surface. A lower elastomeric pad fits against the tapered under surface of the retention flange in direct surface-to-surface contact.

Abstract: A demolition hammer is provided that includes a housing that is reversible and a plurality of interchangeable wear plates. The demolition hammer may include a housing a housing having a first wall and a second wall opposite the first wall, and a power cell disposed within the housing, the power cell having a front face, wherein the housing is reversible such that the housing can be used with the power cell in a first orientation in which the front face faces the first wall and a second orientation in which the front face faces the second wall.

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

Abstract: A slap hammer including an adjustable striking member and a releasable retaining mechanism for releasably retaining a sliding weight is disclosed. One described slap hammer comprises a guide rod having a first end and a second end; a striking member coupled to the second end of the guide rod and movable relative to the first end of the guide rod; a sliding weight slidable along the guide rod between the first end of the guide rod and the striking member; a biasing element positioned between the sliding weight and the first end of the guide rod, the biasing element biasing the sliding weight towards the second end of the guide rod; and a releasable retaining mechanism for releasably retaining the sliding weight against the action of the biasing element.

Abstract: A rotary hammer includes a motor, a spindle coupled to the motor for receiving torque from the motor, a piston at least partially received within the spindle for reciprocation therein, a striker received within the spindle for reciprocation in response to reciprocation of the piston, and an anvil received within the spindle and positioned between the striker and a tool bit. The rotary hammer also includes a retainer received within the spindle for selectively securing the striker in an idle position in which it is inhibited from reciprocating within the spindle, and an O-ring positioned between the retainer and the spindle. The O-ring is disposed around an outer peripheral surface of the anvil. The O-ring is compressible in response to the striker assuming the idle position. The compressed O-ring imparts a frictional force on the outer peripheral surface of the anvil to decelerate the anvil.

Abstract: A hydraulic, pneumatic, or electric tool may include a spindle that is adapted for rotational movement. A swing arm may be coupled to the spindle such that the rotational motion of the spindle is transferred to the swing arm. The swing arm may make contact with an anvil such that the rotational motion of the swing arm causes the anvil to move in a first direction along a linear path. A piston may be operatively coupled to the anvil to follow the linear movement of the anvil. The piston may be adapted to interact with an energy storage medium when the swing arm moves the anvil in the first direction, thereby 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 anvil, thus allowing the energy storage medium to urge the piston and the anvil in a second direction opposite the first direction.

Abstract: A hammer mechanism including: a motor; a piston reciprocatingly driven by the motor; a ram reciprocatingly driven by the reciprocating piston via an air spring; a beat piece supported in an axially slideable manner within a beat piece support structure which, during the normal operation of the hammer mechanism, is repetitively struck by the ram and which transfers the impacts to a cutting tool when held by the tool holder; wherein the beat piece comprises a first impact surface and the beat piece support structure including a second impact surface, the first and second impact surfaces coming into contact with each other when the beat piece axially slides to its furthest position away from the ram; and wherein the shape of the two surfaces relative to each other is arranged so that there is a non-uniform amount of contact between the first and second surfaces around the longitudinal axis.

Abstract: The invention relates to a handheld machine tool, in particular a hammer drill and/or chipping hammer. The tool has an impacting unit which has at least one impacting pin and a guide unit which is provided for guiding the impacting pin. It is proposed that the guide unit is formed from at least two different materials.

Abstract: A method and pile-driving device for driving a support into a ground surface. The device comprises a cylinder, an anvil which closes the lower side of the cylinder at least substantially, a ram which is movable as a piston above the anvil within the cylinder, and an injection device for injecting fuel into a combustion chamber between the anvil and the ram. The device has adjusting means for adjusting the moment of fuel injection and/or the amount of fuel to be injected. The method includes: causing the ram to move downward; injecting fuel into the combustion chamber; causing the fuel to combust for driving the ram upward, in such a manner that said combustion occurs before the ram strikes the anvil, wherein the moment of fuel injection and/or the amount of fuel to be injected is/are adjusted in dependence on at least one variable.

Abstract: A tool for aligning a wind turbine tower fastener includes a shaft having a first end and a second end. A first stop is disposed on the shaft proximate a first end of the shaft and a second stop is disposed on the shaft between the first end and the second end. The tool also includes a ram reciprocally movable about the shaft between the first stop and the second stop for applying a force to the first stop and the second stop respectively. The tool further includes a fastener engaging structure disposed proximate the second end for engaging at least a portion of a fastener and transferring the force applied by the ram to at least one of the first stop and the second stop effective to urge movement of the fastener responsive to the force for aiding alignment of the fastener.

Abstract: The present invention comprises a steel outer tubular sleeve cooperating with an inner steel rod that is dimensioned to slide relative to the outer sleeve. In a first embodiment, a steel slug is welded in the sleeve at its upper end and designed to strike an upper end of the inner steel rod. In an alternative embodiment, the steel slug is welded in the sleeve at its lower end and designed to be struck by the lower end of the inner steel rod. Completing the assembly is an attachment member that in the first embodiment is removably attached to the lower end of the inner steel rod and that in the alternative embodiment is removably attached to the lower end of the outer tubular member. The attachment member is designed to hold a stake of a given cross-sectional dimension.

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 defining a drive axis and a plurality of vent openings. 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. The lifting system raises the hammer during each cycle. 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 drops and 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 drops and is below the second vent location, air within the main chamber is compressed to preload the helmet member prior to contact between the hammer and helmet member.

Abstract: The handheld power tool (10) has a pneumatic striking mechanism (12) that has an exciter element (17), a striking element (17) and an anvil (28). A mechanical spring 8(32) exerts force onto the anvil (26) in the direction opposite from the striking direction (24) of the pneumatic striking mechanism (12).

Abstract: A drop hammer for driving a pile. The drop hammer of the present invention comprises a housing member, a ram member, a helmet member, and a lifting system. The housing member defines a housing chamber and a vent port defining a preload position. The ram member is supported for movement within the housing chamber. When the lifting system raises the ram member above the preload position, ambient air substantially freely flows into and out of the housing chamber through the vent port. When the ram member falls below the preload position, ambient air within a preload chamber portion of the housing chamber compresses to apply a preload force on the inner portion of the helmet member. When the ram member moves into the lower position, the ram member impacts the helmet member to force the helmet member from the rest position to the impact position, thereby driving the pile.

Abstract: A percussive drill bit provided with an improved chuck assembly for a down-the-hole drill hammer. The bit has a head at its forward end with a shank extending from the head. The shank is screw threaded along its length. A reciprocating chuck is provided as a sleeve with internal screw thread as corresponding to those of the shank. The shank is releasably secured in the chuck with the read end of the shank providing a striking face. An arrangement of external splines on the chuck, and a retaining shoulder at its rear end, provide for the required guided movement of the chuck within a drill hammer wear sleeve.

Abstract: The present invention relates to a combustion-type pile-driving device, comprising a cylinder having a closed upper end and an open lower end, which cylinder is freely movable as a piston with respect to an anvil which seals the lower end of the cylinder, a ram which is freely movable as a piston with respect to the cylinder and the anvil in the cylinder, and an injection device for injecting a fuel into a combustion chamber formed between the ram and the anvil in the cylinder for driving the ram upward by combustion of the injected fuel, wherein a second injection device is provided for injecting fuel into a second combustion chamber formed in the cylinder between the ram and the closed upper end of the cylinder for driving the ram downward and driving the cylinder upward by combustion of the injected fuel. The invention further relates to a method for using such a pile-driving device.

Abstract: A bit retainer system includes a bit having a head and a shank, a driver sub disposed around the shank of the bit and adapted to engage a hammer case, a bit retainer including a segmented retainer ring configured with a circumferential groove on an outside diameter of the segmented ring, the bit retainer disposed around the shank of the bit and abutting an upper end of the driver sub. The bit retainer system further includes a secondary retainer disposed around the bit retainer, wherein the secondary retainer includes a plurality of webs disposed at selected locations along the secondary retainer configured to engage the circumferential groove of the segmented retainer ring.

Abstract: A pile driver is provided for use in deep water with a remotely operated vehicle (ROV) and a working ship for setting piles, pin piles and well conductors in subsea soil and for soil sampling in deep water and can be used for shallow water and land-based applications. A ram mass or hammer is received in an open frame and hydraulically reciprocated while in contact with water. A piston rod received in a piston cylinder is secured at one end to the hammer through a coupling mechanism, and an external source of hydraulic power is used with an on-board hydraulic circuit. Gas is compressed during an up-stroke to store energy, which is released during a down-stroke to push the hammer downwardly. The coupling mechanism provides a connection between the piston rod and the hammer that can move between an essentially rigid lift connection, an essentially rigid downward-push connection and an essentially non-rigid impact connection for preventing buckling of the piston rod when the hammer strikes at its lowermost point.

Abstract: The invention is to provide a hammer drill which is to be capable of restricting rotation of a bit in a hammer mode, and improve usability. A hammer drill includes a lock plate 51 in a housing 2, and the lock plate 51 engages with a second gear 31 so as to lock rotation of the second gear. The lock plate 51 is provided to be slidable between an engaging position with the second gear 31 and a non-engaging position, and is biased to the engaging position by a coil spring. The hammer drill further includes a restriction part 50 on an outer peripheral side of a holding tube 46 in a mode switching knob 44. The restriction part 50 abuts the lock plate 51 in one of two phases for engaging a clutch 37 with only a boss sleeve 32 so as to hold the lock plate 51 at the non-engaging position, and cancels the abutment with the lock plate 51 in the other phase to slide the lock plate 51 to the engaging position.

Abstract: A hand-held power tool includes a percussion power tool includes a percussion piston (5) for applying blows to an anvil (8) axially displaceable in a guide tube (6) within limits defined by two, spaced from each other, stops (9a, 9b) arranged in the guide tube (6), a pneumatic percussion mechanism (2) for driving the percussion piston (5), an air spring (3) for connecting the percussion piston (5) with the percussion mechanism (2), and an impact ring (12) arranged coaxially with the anvil (8) outwardly thereof and having spaced from each other, inner radical flanks (14) located on opposite axial sides of the outer radial collar (11) provided on the anvil (8), with the impact ring (12) freely axially displaceable, within limits, relative to the outer radial collar (11) and having an outer diameter smaller than a guiding inner diameter of the guide tuber (6), and with a mass ratio of the impact ring (12) to the anvil (8) being equal at least 0.25.

Abstract: A bit retainer system is disclosed. The bit retainer system includes a bit having a head and a shank, a driver sub disposed around the shank of the bit and adapted to engage a hammer case, a bit retainer disposed around the shank of the bit and abutting an upper end of the driver sub, and a secondary retainer disposed around the bit retainer.

Abstract: A tool holder for a hammer comprises a tool holder body having a forward end for non-rotatably receiving a shank of a tool. The tool holder body defines an axially extending slot. A locking body extends through the slot for releasably engaging an axially extending closed groove formed in the tool shank. A locking ring surrounds the tool holder body and in a locked positions holds the locking body in a radially inward position in which the locking body engages the groove in the tool and in a release position allows the locking body to move into a radially outward position so that a tool can be inserted into or removed from the tool holder body. The locking ring is shiftable in a direction transverse to the fore-aft axis of the tool holder body to allow the locking body to move into a radially outward position.

Abstract: A scaling apparatus comprises a hammer component and a pick component which includes a tooth. The apparatus also includes a mechanism for moving the pick component with respect to the hammer component to thereby impart a scaling force to and through the tooth. In a preferred embodiment of the invention, the pick component includes a pick body comprising a first pivot having a pivot axis and a tooth mounted on the pick body. In this embodiment of the invention, the hammer component includes a hammer housing and a second pivot mounted within the housing and adapted to pivotally engage the first pivot of the pick body. This embodiment of the invention also includes a mechanism for rotating the pick body relative to the hammer component so as to impart a scaling force.

Abstract: An impact tool enables a front cover part to be easily attached to and detached from a housing body, with a device having a simplified structure. The front cover part has an annular fastening portion clamped to the outer peripheral surface of a front edge portion of the housing body, a cylindrical portion extending from the front end of the housing to the region of the fastening portion, and a connecting portion connecting together the cylindrical portion and the fastening portion. The fastening portion is split at a circumferential part thereof to form a pair of circumferentially opposing tongue-shaped portions. A clamping device is provided between the tongue-shaped portions, which is movable between a clamping position where it pulls the tongue-shaped portions toward each other and an unclamping position where the tongue-shaped portions are released from being pulled toward each other.

Abstract: An impact tool enables a front cover part to be easily attached to and detached from a housing body, with a device having a simplified structure. The front cover part has an annular fastening portion clamped to the outer peripheral surface of a front edge portion of the housing body, a cylindrical portion extending from the front end of the housing to the region of the fastening portion, and a connecting portion connecting together the cylindrical portion and the fastening portion. The fastening portion is split at a circumferential part thereof to form a pair of circumferentially opposing tongue-shaped portions. A clamping device is provided between the tongue-shaped portions, which is movable between a clamping position where it pulls the tongue-shaped portions toward each other and an unclamping position where the tongue-shaped portions are released from being pulled toward each other.

Abstract: A rock drilling apparatus includes a drill string terminating in a drill chuck (32) and a drill bit (16) detachably fitted into the drill chuck, the drill bit having a shank (18) received in the drill chuck, the drill chuck (32) and the drill bit shank (18) having complementary splines and grooves allowing rotation or movement of the drill chuck to be transmitted to the drill bit whilst allowing limited longitudinal movement of the drill chuck relative to the drill bit. The drill bit has a drill head (22) at its lower end which is of greater diameter than said shank, said head having a part (26) above that lower end and below the splined region.

Abstract: A tool holder for a hammer comprises a tool holder body having a forward end for non-rotatably receiving a shank of a tool. The tool holder body defines an axially extending slot. A locking body extends through the slot for releasably engaging an axially extending closed groove formed in the tool shank. A locking ring surrounds the tool holder body and in a locked position holds the locking body in a radially inward position in which the locking body engages the groove in the tool and in a release position allows the locking body to move into a radially outward position so that a tool can be inserted into or removed from the tool holder body. The locking ring is shiftable in a direction transverse to the fore-aft axis of the tool holder body to allow the locking body to move into a radially outward position.

Abstract: A rock drilling machine comprising a rotating device (1), a percussion device (2) and a shank (17) where a tool (18) is to be fastened. According to the inventive idea, lubricant used for lubricating the shank is supplied in suitable conduits to pressurize the holes (3a′-3f′) of coupling bolts that join together the different parts of the drilling machine and delivered further in suitable conduits to serve as lubricant on the bearing surfaces between the rock drill and the feed equipment (21).

Abstract: A device for ultrasonic peening of metals is intended for strengthening and relaxation treatment of metal surfaces with an ultrasonic oscillation and includes an ultrasonic generator (1) having the optimized power of from 0.2 to 0.5 kW, a piezoelectric transducer with an ultrasonic velocity transformer (6) and a set of readily replaceable heads with striking tools (pins). Various sizes and arrangements of the tools allow for ultrasonic peening of parts of complicated configuration fast and efficiently. In the device, drop-wise cooling and lubrication of striking tools, as well as of treatment area are provided.

Abstract: The invention relates to an arrangement in connection with a hydraulic breaking apparatus, the arrangement comprising a housing (4) placed around a percussion hammer (1), and a changeable wearing element (6) arranged at the lower part of the housing. The wearing element (6) receives blows and forces directed at the lower part of the housing (4). The wearing element (6) is fastened in such a way that it can be detached and changed easily and rapidly, if required. Further, the structure of the breaking apparatus may also be such that when the wearing element (6) is removed, it is possible to carry out the maintenance and repair operations of the lower frame (1b) of the percussion hammer without disassembling the upper frame (1a) of the percussion hammer.

Abstract: A hydraulic ramming apparatus including an apparatus body (14) having a cylinder bore (23) and a guide bore (24) that are successively formed to each other in the apparatus body (14). A piston (30) is slidably inserted into the cylinder bore (23) so as to be reciprocable within the cylinder bore (23). An upper pressure-receiving chamber (31) is defined at an upper end portion side of the piston (30), and a lower pressure-receiving chamber (32) is defined at a lower end portion side of the piston (30). A ramming tool (19), having a rod body (35), can be detachably inserted into the guide bore (24). Also, a mechanism for moving the rod body (35) is provided so as to follow upward movement of the piston (30).

Abstract: A percussion tool, such as a drill or a chisel tool, including a percussion mechanism (7), a tool chuck (1), and a damping member (8) arranged between the tool chuck (1) and the percussion mechanism (7) for damping rebounds of a header (9) axially displaceable in the tool chuck (1), with the damping member (8) having, arranged one after another in the operational direction, a stop disc (86), an elastic ring (83), and a transmission element (81) having a cavity for receiving both the stop disc (86) an the elastic ring (86).

Abstract: The present invention realizes effective recoil reduction and idling strike prevention with a minimum constitution. In a tool holder (6), a thermal-resistant O-ring (22) is arranged between two steel washers (21,23) near the joint to the barrel (5). The O-ring (22) has a cross-sectional diameter of approximately 7 mm. The inner diameter of the O-ring (22) is made slightly greater than the diameter of a cylindrical portion (19b) formed at the rear of an intermediate element (19) and slightly smaller than the diameter of a flange (19a) formed at the rear of the cylindrical portion (19b). Likewise, the inner diameter is made slightly greater than the diameter of a recess (18b) of a striking member (18) formed in front thereof and slightly smaller than the diameter of a flange (18a) formed in front of the recess (18b).

Abstract: A chuck and drill bit combination for insertion into a front end of a percussive, down the hole drill forming a part of a cluster drill assembly, for selectively engaging and disengaging the chuck and drill bit during drilling operations includes the bit and chuck each having splines and grooves adapted to overlap and engage each other in a first stop position and further adapted to disengage from each other in a second stop position, whereby the bit is restrained from rotational movement but capable of axial movement in the first stop position and capable of both axial and rotational movement in the second stop position, to provide automatic indexing of the bit so as to position the bit's gage drilling buttons in a preferred position outboard of the drill centerline, to maintain maximum borehole diameter.

Abstract: A fluid-activated, percussive impact tool has a piston therein that reciprocates longitudinally but not rotationally. The piston activates a wrap spring clutch to rotate the drill steel. A removable splined nut in combination with the tool's housing restrains rotation of the piston, while permitting longitudinal reciprocation of the piston.