Abstract: An accessory for a jack hammer that includes clamping means for gripping the upper end of the stake so that the stake can be controllably driven into the ground by the user. The accessory includes a stake receiver that has a channel into which the end portion of the stake is inserted and further includes a jaw and clamping means for forceably retaining the jaw against the inserted stake. The channel includes guide ways that permit it to be used interchangeably with the more common sizes and shapes of stakes.

Abstract: A conventional stake member having an annular post mount joined to the upper end of the stake to form a socket for receiving the lower end portion of a right angular extension of the elongated mounting member of a slide hammer. A right angle hammer member has a lower terminal edge for forming a mating fit with the top edge of the stake when the extension extends into the socket and a pin removable attaches the stake to the hammer member and extension. The upper end portion of the rod which forms part of the mounting member mounts an anvil having a top surface and a bottom surface to be selectively struck by a slide member for the selective one of pulling the stake and driving the stake into the ground, the slide member being reciprocal relative to the mounting member. The anvil is located within the slide member. The lower end portion of the rod is welded to the apex of the extension.

Abstract: The present invention relates to a drill rod for percussion drilling machine comprising a rod or a sleeve-shaped element that is provided with a threaded portion for engagement with another correspondingly threaded drill rod element. In order to reduce the risk for pitting damage, the threaded portion is provided with a wear lining that is metallurgically bonded to the rod. The lining is made of a metallic material that is softer than the material of the element, the latter usually being steel.

Abstract: Slide hammer apparatus including means for restraining and non-rotatively driving and pulling fence posts. A handled, hammer section mounts in concentric, sliding relation to a main body which surrounds a fence post and contains upper and lower stops. At least one stop includes an adjustable clamp means and anvil acting pin for securing a post to the main body and permitting reciprocal motion.

Abstract: A punch tool for applying force to a work piece includes a body, a grip mounted on one end of the body, a punch connected to the other end of the body, and an anvil pivotally connected to the body between the grip and the punch. A method for disengaging a fastener from an object in a limited work space includes inserting the punch of the tool into the work space in engagement with the fastener and striking the anvil with force sufficient to disengage the fastener. A method for punching a hole in an object at a point within a limited work space includes inserting the punch portion of the tool into the work space in engagement with the point and striking the anvil with force sufficient to punch a hole in the object.

Abstract: A drill string element for use in top hammer percussive drilling comprises first and second tubes coupled together by a cylindrical thread, and at least one impact-transmitting ord slidably disposed in the tubes. The rod(s) includes abutments which engage restrictions formed at remote ends of the tubes whereby the rod(s) can be removed only by unscrewing the tubes from one another. Remote ends of the tubes define male and female conical threads which enable the element to be connected to similar elements in the forming of a drill string. The conical threads are easier to unscrew than the cylindrical threads to avoid an accidental separation of the tubes of each element when that element is being unscrewed from another element.

Abstract: A land anchor includes a hammer element that permits the anchor to be driven into the soil. The anchor also includes a stabilizing assembly that increases the anchoring force of the anchor for loose soils. The stabilizing assembly includes a wing section that is expanded from a stored, ground-entering configuration to a ground-gripping configuration by operation of a screw extending within a central rod of the anchor. The hammer is located on the rod.

Abstract: A downhole drill bit having an elongated male drive shank, a separate female impact head mounted on the drive shank, the drive shank and head having cooperating external and internal, head drive splines extending helically in one angular direction to urge the drive shank and head together during impact drilling, the head drive splines having a width and spacing for inserting and then rotating the head on the shank, and elongated key inserts between the head drive splines to form therewith a head drive coupling, the head having an annulus and the drive shank having a circular arrangement of locking lugs receivable within the annulus for locking the head against axial withdrawal from the shank.

Abstract: A ram boring implement having a pneumatically or hydraulically driven percussion piston, movable axially in a reciprocating manner in a housing, and an axially movable bit which is connected to an end of the housing and acted upon directly or indirectly by the percussion piston, is of a structure which permits a restoring piston, connected to the bit, to be acted upon by the pneumatic or hydraulic pressure during the return stroke of the percussion piston.

Abstract: For driving of ramming parts under water, a first ramming device is suspended on the supporting element and a second ramming device is suspended on a further supporting element, a submergible electrohydraulic drive unit is located laterally near or under one of the ramming device and connected with both ramming devices by hose conduits, the ramming devices with the drive unit are lowered so that at least one ramming device is placed on one ramming part and after driving it in over a predetermined path it is transferred to another ramming part, while the other ramming device drives further the first ramming part or a further ramming part, and both ramming devices are driven one after the other or simultaneously with one another by the same drive unit.

Abstract: The present invention relates to a drill rod for percussion drilling machines comprising a rod or a sleeve-shaped element that is provided with a threaded portion for engagement with another correspondingly threaded drill rod element. In order to reduce the risk for pitting damage, the threaded portion is provided with a wear lining that is metallurgically bonded to the rod. The lining is made of a metallic material that is softer than the material of the element, the latter usually being steel.

Abstract: A tool attachment for a percussion drill power tool which expands and sets, essentially but not limited to, fastening anchors used in concrete and masonry. The tool's body is generally cylindrical and is mostly hollow to slip over a drill bit (38, 74) of the percussion drill, using a spring clip (24, 124) to keep it from falling off. The opposite end of the tool has either a coaxial concave recess (54, 154, 354, 454) to place onto an anchor (58) or a coaxial plunger (260) to slip into a mostly hollow anchor (258) that are placed into a drilled hole (64, 264). The anchor (58, 258) is then expanded and set into the concrete or masonry by the hammering action transmitted through the tool by the percussion drill.

Abstract: A drill bit for use in a drill string comprising a set of a plurality of central rod members and a set of a plurality of tubular members surrounding said rod members. The drill bit is provided with a longitudinally extending flushing channel which communicates with an annular space between the rod members and the tubular members via a transverse passage. The flushing channel comprises at least two end passages terminating in the bit front. The cross section area of each of the end passages is smaller than the overall cross section area of the portion of the flushing channel located between the end passages and the transverse passage.

Abstract: The invention relates to a drill element for percussion drilling, the element having a cylindrical screw thread having one single entry. The screw thread, that is intended for thread diameters of less than 30 mm, has a pitch of less than 12 mm, a shoulder angle of less than 69.degree., and a pitch angle of less than 11.degree. but more than 5.6.degree..

Abstract: A self-righting roadway marker support for a flexible boundary or roadway marker has a hollow anchor sleeve sunk into a supporting surface, a mounting collar secured to said anchor sleeve, a pivot strut extending through and upward from the collar, a compressible coil spring to resiliently urge the strut into contact with the collar, and a spring stop which selectively limits the extent to which the coil spring may be compressed. An oblong, radiused or chamfered aperture formed in the collar cooperates with a spring-mounting eyebolt to prevent the strut from rotating when deflected. A tool is also disclosed for installing the marker support. The force required to deflect the support assembly is set to be less than the force that would destroy or permanently set or deform the boundary marker.

Abstract: A fluid impact tool of the type known as a percussion or rock drill characterized by a percussion mechanism which provides alternative reverse percussion to assist in drill string removal or recovery.

Abstract: Apparatus for pneumatically stamping identifying impressions on a workpiece is provided. The apparatus includes a double-acting air cylinder having a hollow piston rod. An impact piston is provided inside the barrel formed inside the piston rod to, alternatively, seal an aperture in the piston or to travel inside the barrel in order to strike a plunger mounted in a plunger housing slidably supported by the leading end of the piston rod. A stamping head having an anvil adjacent to the stamping characters is provided to be mounted on the end of the plunger housing. In operation, compressed air is injected behind the piston rod thereby extending it toward the workpiece while compressed air is provided ahead of the impact piston to retain it in seated position on an aperture in the piston of the piston rod. When the stamping characters engage the workpiece, further advancement of the piston rod closes the source of compressed air ahead of the impact piston and opens venting apertures.

Abstract: A rock breaker tool for use with earth working apparatus is disclosed. The tool includes a ripper tooth employed with a hammer and anvil arrangement located above the upper portion of the tooth. The present invention is so constructed as to minimize the transfer of force directly from the hammer to the hydraulic cylinders of the earth working apparatus. The invention may be employed with various types of earth working apparatus, including backhoes, bulldozers and ripper buckets.

Abstract: In an apparatus for driving open-ended pipes through the ground, a hollow intermediate piece having a truncated conical transition portion with outlet openings for the removal of soil, which is forced into the pipe during driving, is disposed between the rearward end of the pipe and a pneumatic rammer for driving the pipe.

Abstract: A pile driver is described wherein a piston within an internal combustion engine is rigidly coupled to the pile to be driven. The engine is resiliently coupled to the pile so as to move with the pile. Control circuitry modifies the frequency of operation of the piston so as to make the impulses created thereby synchronous with reflected impulses within the pile.

Abstract: An apparatus is disclosed for driving or retracting ground rods or other rod-like members and preferably includes an element for forcibly urging a body portion in longitudinal directions generally parallel to the rod or rod-like member being driven or extracted, opposed jaw members slidably connected to the body portion for receiving rod or other item to be driven therebetween, and abutment members fixed to the body portion for forcibly urging the jaw members laterally toward one another into a gripping engagement with the rod, thereby forcibly urging the jaw members and the rod or rod-like member in a driving longitudinal direction. The body portion of the ground rod driving or extracting apparatus is preferably interlockingly connectable to various adapter or anvil apparatus for use with either manual or powered force-applying devices and for interchangeable use with such devices in either rod-driving or rod-retracting operations.

Abstract: A tool for driving into the ground pegs having a central sleeve and projecting fins, said pegs being adapted for anchoring stakes into the ground, said tool comprising a rod-like body with pointed lower end and a projecting central part forming a lower transverse surface which is adapted for bearing on the projecting fins of the peg and a ram member sliding along the upper part of the rod-like body to impart blows on said projecting central part. The tool of this invention has a bell-shaped member capping the projecting central part and a flat member assembled to the base of the projecting central portion. It has particularly high resistance to the blows and allows easy replacement of its most fragile parts in case of wear or breakage.

Abstract: The invention comprises an accessory for use with a driver for forceably inserting friction rock stabilizers into bores formed in earth structures (such as mine roofs). In the depicted embodiments, the Accessory comprises an elongate body having a driver element with a pin or boss at one, lower, "driven" end of the body for engaging and supporting an end of a stabilizer, and a second driver element with a socket, at the opposite, upper, "driving" end of the body for receiving an insertion tool. The latter driver element can be pivotably offset, to accommodate an angled, unobstructed address of the insertion tool to the upper end of the body, and to enable a linear insertion of a stabilizer, supported on the lower end of the body, into a bore.

Abstract: A pressure-medium driven percussion device including a body, a drill shank gliding axially in the body for transmitting percussions to a drill rod and a percussion piston moving in the body for directing percussions axially to the drill shank. The drill shank includes a lifting piston which moves in a lifting cylinder within the body. The body further includes a channel passing to the lifting cylinder for supplying and removing pressure medium into and out of the lifting cylinder and seals located between the body and the drill shank at both sides of the lifting cylinder. An equalizing channel is located between each seal and a corresponding choking slot. A valve connects the equalizing channels to the source of pressure medium when a channel passing to lifting cylinder is connected to a pressure medium container, and, correspondingly, to the pressure medium container when the channel passing to the lifting cylinder is connected to the source of pressure.

Abstract: A driving device (10) for removable attachment to a post (100) to allow driving of the post into the ground is described. The device is characterized by a body portion (12) which loosely fits onto the end of the post and a cap portion (11) closing one end of the body portion to provide a surface (11a) for driving the post into the ground. Retaining means along one side of the body portion is provided in the form of a curved spring (13) which engages a side (100a) of the post. On the opposite side (100b) of the post a spring (18) loaded arm (15) urges a hook (17) into the side (100b) to stabilize the device during driving and to allow rapid removal of the device. The device is removed without damage to the post after driving.

Abstract: A device for punching holes of varying size in sheet metal by a pneumatic hammer. A tapered punch is employed with an adjustment at the muzzle end of the hammer which selectively limits the travel and penetration of the punch thereby determining the size of the hole. A special attachment for the tapered punch and a punch holder for the punch is provided for attachment to the muzzle end of the pneumatic hammer. The attachment is in the form of a housing which receives the punch and punch holder and can be screwed on the muzzle end of a pneumatic hammer and present the punch holder to the internal hammer like drive of a conventional pneumatic hammer.

Abstract: The invention comprises an Accessory for use with a driver for forceably inserting friction rock stabilizers into bores formed in earth structures (such as mine roofs). In the depicted embodiments, the Accessory comprises an elongate body having a driver element with a pin or boss at one, lower, "driven" end of the body for engaging and supporting an end of a stabilizer, and a second driver element with a socket, at the opposite, upper, "driving" end of the body for receiving an insertion tool. The latter driver element can be pivotably offset, to accommodate an angled, unobstructed address of the insertion tool to the upper end of the body, and to enable a linear insertion of a stabilizer, supported on the lower end of the body, into a bore.

Abstract: An improved drilling rig is the subject of this application. The rig includes a drilling tower (10) having a ram (16) for applying down pressure to a length of drill rod (12). A lever member (42) is suspended from the ram (16) and permitted to float toward and away from the ram (16) by being mounted for movement along tracks provided by a plurality of eyes (50) elongated in directions toward and away from the ram (16). Suspension bolts (52) extending through the eyes (50) at one end (72) of the lever member (42) are allowed to ride upwardly to the upper extremity of the eyes (50) to form a point about which the lever member (42) pivots. A percussion assembly (26) includes a piston (34) which percussively engages the lever (42) at its opposite end (70). The percussion assembly (26) is laterally off-set from the axis of the drill rod (12). The percussive force imparted to the lever member (42) is translated to the upper end (30) of casing (28) encircling the drill rod (12).

Abstract: An improved nailing tool for supporting and driving a nail in which an elongated tubular guide sleeve member has means at one end for releasably retaining a nail to be driven and a hand grip at the opposite end. The nail driving rod is axially slidable in an elongated tubular guide sleeve member in which the lower end engages the nail retaining means and the upper end extends beyond the hand grip with the nail retaining means having an anvil in which there is an axial bore for cooperatively receiving a nail head therein with the anvil having a substantially planar driving rod impact surface on the face of the anvil opposite from the bore. Means are included in the axial bore for releasably engaging a nail head upon axial displacement of the nail driving rod in the guide sleeve member.

Abstract: A cap formed of cast steel is permanently attached to the top end of a tubular metal caisson to facilitate the handling of the caisson and its installation with a sonic or vibratory driver/extractor mechanism. The cap has an annular base formed with a relatively large central opening. A plurality of bolt-receiving holes are formed in the base and are spaced in an arrangement for subsequent mounting of a superstructure on the caisson. A pair of diametrically spaced clamping plates is formed integrally with the base for cooperative engagement with the vibratory mechanism. A pair of diametrically spaced lifting lugs are mounted on the base between the clamping plates to facilitate the handling of the cap and caisson. The clamping plates each have a straight chordlike center section and may have a pair of end sections. The cap has a size slightly larger than the size of the caisson top end and is secured thereon by one or more welds.

Abstract: A pneumatic impact tool has a tubular housing with an impact head secured in and extending outwardly from one end of the housing and a valve secured within the housing but spaced from the impact head so that a piston chamber is formed within the housing. The valve has an inlet port adapted to be connected to a source of pressurized fluid and two outlet ports for the alternate release, respectively, of pressurized fluid. One outlet port opens directly into the piston chamber while the other is connected by a passage to the piston chamber immediately adjacent the impact head. At least one exhaust port is provided through the housing for exhausting pressurized fluid from the piston chamber when the piston reaches the end of its travel in each direction of its stroke. The housing is adapted to be connected to a source of pressurized fluid so that pressurized fluid enters the inlet port of the valve.

Abstract: An attachment for driving pipe wherein a plurality of concentric sleeves having diminishing diameters are arranged in driving engagement with a pipe end with a driving hammer operating to impart a driving force to the pipe, the sleeves being arranged to form a generally concial configuration such that the sleeves are in contact with each other at points which lie along lines of contact intersecting at the axis of the driving hammer to form an acute included angle.

Abstract: An attachment (15) for a percussive rock drilling machine (12) for withdrawing a drill steel from a drilled hole. The drilling machine is of the kind which is displaceable along a feed beam (14) by a feeding motor. The attachment (15) comprises a spring housing (17) which contains a compressive spring (22) and a stopping member (23), the housing being suspended by flexible means (26, 27) from a yoke-shaped member (18) coupled on to the drilling machine body (19). The stopping member (23) is arranged to abut against a coupling sleeve (32) or the like on the drill steel (16). When retracting the drilling machine (12) by the feeding motorand starting the ordinary percussive action, the impacts directed downwards will be transformed to impacts directed upwards which loosen and withdraw the stuck drill steel (16) from the drilled hole.

Abstract: A pile driving device of the drop hammer variety is disclosed and includes a crane supportable housing containing a hydraulic drive motor and a cam member for executing generally circular motion within the housing in response to operation of the drive motor and a ram depending from the housing of a substantial mass and having a bearing plate selectively engageable by the cam with cam motion sequentially raising the ram and disengaging the bearing plate to allow the ram to free fall and impact a pile. Also depending from the housing is a vertical guide arrangement for limiting ram motion to generally vertical reciprocating motion limited at one end by the pile being driven and at the upper extreme by the uppermost position of the cam member. The drop hammer assembly may further include a sleeve which is removably attachable to a pile upper end and which extends upwardly therefrom to provide a sleeve portion in which the ram may reciprocate.

Abstract: The operator of a taphole drilling apparatus for blast furnaces performs manual changes on the apparatus in its safe position of rest and operation by remote control and automatic latching in hazardous taphole work including drilling and subsequent driving, release, and extraction of a tap bar. The usual guide rail (22) carrying reciprocably a hammer drill (30) thereon incorporates a remotely openable automatically latching centralizer (42) at its forward end and an extraction carriage (29) on which, after removal of the drill steel (43), an impact sleeve (50) can be manually mounted for being impacted by the hammer drill (30). In one mounting position (FIG. 5) of the impact sleeve (50), a latch (57) therein is biased to automatically latch the shank of a tap bar (53) thereto for extraction by impacts. In a 180.degree. counter-turned position the latch (57) will fall aside and the mounted sleeve (50) is used to drive the tap bar while guided by the centralizer (42).

Abstract: A striking apparatus that includes a reciprocating striking piston operable by a pressure mechanism, a cylindrical body, the improvement comprising a sleeve bushing mounted inside of the cylindrical body in slidably fitted assembly therewith. The sleeve bushing has a drive gear at one end for rotary engagement with a drive motor. A rotary tool and piston shank and piston are all integrally combined as a one piece unit and at least partly received in coaxial alignment within the tubular bushing. Spline gearage exists between the tubular bushing and the piston shank enabling co-rotational rotary movement together upon actuation of the drive gear through operation of a drive motor operatively connected therewith. A piston cylinder in the cylindrical body along with the piston is reciprocably movable in the piston cylinder. The shank has a shank face facing in the direction opposing the striking piston and with the shank face transferring the feed force from the body through the sleeve bushing to the rotary tool.

Abstract: A knocking arrangement for cleaning electrodes of an electric precipitator has a plurality of hammer members mounted on a rotary shaft, a plurality of anvil members arranged so that the hammer members strike against the anvil members, and connecting elements including a V-shaped holding member with a closed end portion embracing one frame member of a frame of the precipitator, and an open end portion provided with two projections, wherein a wedge member carrying the anvil member is received into the holding member between the projections and the one frame member.

Abstract: The invention comprises an Accessory for use with a driver for forceably inserting friction rock stabilizers into bores formed in earth structures (such as mine roofs). In the depicted embodiments, the Accessory comprises an elongate body having a pin or socket at one, "lower", "driven" end for engaging and supporting an end of a stabilizer, and a limb or socket at the opposite, "upper", "drive" end for receiving a driver. The latter limb or socket is offset, to accommodate an angled, unobstructed address of the driver to the upper end of the body, and to enable a linear insertion of a lower-end-supported stabilizer into a bore. In accommodating a driver at the upper end of the body, to forceably insert a stabilizer which has its termination supported on the lower end of the body (the insertion force, therefore, being applied through the body), the Accessory facilitates bore insertion of lengthy stabilizers, by means of conventional drivers, in low headroom, subterranean openings.

Abstract: A pile is lofted to a vertical position over a driving location. At a distance above its lower end the pile is embraced within a guide on an extensible rack on the crane chasis. Over the upper end of the pile a vertically elongate socket on the lower end of a hammer carriage is fitted, and driving ensues until the pile is self-sustaining, or until the hammer carriage nears the rack. Then the rack is disengaged from the pile and withdrawn, and driving is completed.

Abstract: An impact tool capable of use in place of a conventional jackhammer, the tool being of the type having an axially moving impact member guided telescopically by a mating guide member, and characterized by the following combination:(a) the impact member is a massive elongated rod, having a length of the order of two feet or greater, a diameter of the order of one inch or greater, and comprised of impact-resistant heavy material such as steel to have a weight of the order of 10 pounds;(b) the guide member is a rigid hollow outer sleeve, having a slidable fit over the massive rod and having a lower end formation of internal shape corresponding to the external shape of the shank of a jackhammer tool bit;(c) a restraint means retains the jackhammer tool bit with its shank inserted into the lower end formation of the guide; and(d) the massive rod and the guide member are cooperatively dimensioned so that the massive rod protrudes to enable a worker to alternately retract the massive rod and propel it against the end

Abstract: A bit retainer for impact type pneumatic tools arranged to be mounted on the tool and to releasably receive a bit. The retainer includes a body having a bore extending therethrough. The bore includes a nose portion of generally elliptical configuration, a center portion of circular configuration and a rear portion of generally elliptical configuration that has its major axis disposed at about 90.degree. relative to the major axis of the front portion of the bore. Radially movable locking members are provided that operate in cooperation with a movable sleeve. The sleeve is movable between unlatched and latched positions which permit and prevent radial movement of the locking members to positively retain the bit unless the sleeve is intentionally moved to the unlatched position.

Abstract: A hammer and more particularly a fluid operable hammer wherein alternating impetus provided by pressurized liquid and gas means actuates a reciprocable hammer piston to generate repetitive impact loads. A work member is provided to receive blows from the hammer and includes an enlarged portion located in a sealed, variable volume cushion chamber. Means are provided to provide fluid above atmospheric pressure in the chamber. The chamber is sealed before hammer operation to provide a variable gas pressure cushioning chamber for the work member.

Abstract: A mining bit, especially an impact bit for down-the-hole operations and the like, in which the bit comprises a body adapted for being chucked in an impact motor for being impacted by the hammer of the motor and for being rotated by the motor. The working end of the bit includes a detachable cup-shaped cap in which hard wear resistant inserts are mounted.

Abstract: In one type of pneumatic percussion drilling tool, the pneumatic motor has an anvil-bit which is slidable in the forward end of the motor casing between a normal working position and an abnormal advanced position when the tool is hanging off bottom and the pneumatic fluid is caused to bypass the hammer-piston and blow continuously through the anvil-bit. In order to prevent tapping or chattering of the hammer-piston at such time, as a result of leakage of the pneumatic fluid into the forward working chamber, this chamber is vented by means of one or more passages formed in the surface of the anvil-bit member which are open while the tool is blowing and which are closed in the normal operating position of the anvil-bit member. Since the passages are only in the surface of the anvil-bit member, the structure eliminates the need for special configurations of parts to provide interconnecting recesses and passages as in certain of the prior art.

Abstract: A pile driving device comprises one or more guide stays, a Diesel hammer, consisting of a combustion cylinder guided by guide means along each guide stay and a hammer piston operating in said combustion cylinder.Lifting the hammer piston at the start of the known pile-driving device takes place by means of a cable of a winch arranged at a large distance. In order to facilitate the starting the hammer piston is lifted by means of a hydraulic cylinder-piston set which via a catch engages the piston on the one hand and the combustion cylinder on the other hand.

Abstract: A pneumatically driven, impact-actuated auto body dent puller has a cylindrical slide weight coaxially movable along a slide shaft for impact against an abutment collar near one end thereof, the slide member being slidably enclosed within a tubular cylinder member having free fitting caps at each end and provided with a through opening near one end connected with a manually controlled valve for impressing a blast of pressurized air behind the slide weight when disposed at the forward end of the slide shaft for projecting the slide weight rearwardly against the abutment collar through the interposed rear end cap, thereby imposing a rearward striking force upon a sheet-metal screw secured at the forward end of the slide shaft which is removably receivable within a punched opening in the dented zone of an area of sheet metal to be repaired.

Abstract: A drill for use especially with percussion drilling machines and rotary drill hammers for working rock and concrete is disclosed. The drill includes an elongated shank having a leading and trailing end, the latter of which is adapted to receive axial blows from the drilling machine. A unitary plastic receiving part at least partly encloses and mechanically interlocks with the shank periphery adjacent the trailing end of the shank. The exterior of the plastic receiving art is threaded for engagement with interior threads of a drilling machineadapter.

Abstract: An airhammer embodies an outer housing structure connectible to a rotatable drill pipe string through which compressed air is conducted. A hammer piston reciprocates in the housing structure, compressed air being directed alternately to the upper and lower ends of the piston to effect its reciprocation in the structure, each downward stroke inflicting an impact blow upon the anvil portion of an anvil bit extending upwardly within the lower portion of the housing structure. Upon elevating the airhammer off the bottom of the bore hole being drilled, the anvil bit drops downwardly of the housing structure to open one or more air bleeding grooves in the anvil bit, compressed air in the housing structure bleeding quickly through such grooves and preventing or stopping the hammer piston from reciprocating and impacting against the anvil bit.

Abstract: A drilling tool consists of a drill and a tubular shaped receiving part fitted onto the trailing end of the drill. The outer surface of the receiving part is shaped to fit into the chuck or retainer of a drilling device which rotates the drill. The inner surface of the receiving part and the juxtaposed surface on the trailing end of the drill are in locking engagement, however, under certain torque conditions the locking engagement will be released so that the receiving part can rotate relative to the drill. Preferably, the locking engagement is established by deflectable projections formed on at least one of the receiving part and the drill which seat into recesses formed on the juxtaposed surface of the other. Passageways are provided between the trailing end of the drill and the receiving part.

Abstract: An impact drilling apparatus has an anvil inside a casing for receiving impact blows from a hammer. The lower end of the anvil is threadably connected to a drill bit having an external load bearing shoulder. On the lower end of the casing is attached a driver guide sub which extends downwardly around the threaded connection between the drill bit and anvil to bear on the external load bearing shoulder for transmitting down weight to the bit and simultaneously counteracting lateral forces acting on the bit and anvil. A spline connection is provided between the driven guide sub and the anvil. In the off bottom position, a shoulder of the anvil comes to rest against the top of the driver guide sub which stops the reciprocating action of the hammer while drilling fluid continues to flow.