Abstract: A pressure actuated, telescoping subassembly is supported by a pipe string to axially move an attached member within a wellbore. Increasing fluid pressure to the subassembly actuates a telescoping action, axially moving the attached member but not the supporting pipe string. Motion can be used during rotary drilling or running of tubulars into a drilled borehole portion. Pressure actuation provides a way to remotely apply axial force to a member, such as a tool or drill string portion. Moving only the member instead of the entire drill string and member lowers the total force required to move members and provides a new way to chase drill bits and apply constant drilling forces. This minimizes the risk of pipe string overloading and buckling, exceeding rig weight limitations, and tool bit damage.

Abstract: A cushion connector (10) used for above ground drilling has pin (11) and box (12) components at opposite ends. A housing (13) extends axially between the pin and box components. A drive spline (22) is operably connected to one of the components and extends outwardly from the axis (23) of the cushion connector (10). A plurality of drive blocks (24) extend inwardly from the inside diameter of the housing (13) and engage with keyways (69) of the drive spline (22). Drive lugs (71) connected to the inside of the housing (13) act on the drive blocks (24) and resilient cushion blocks (70). A spring (30, 60) extends between the pin (11) and box (12) components within the housing (13) and exerts axial force between them. The drive splines (22) are coaxial with the connector (10) and move axially under operation. Cushion blocks (70) are provided between the drive blocks (24) and drive lugs (71).

Abstract: The present invention is a drilling tool including a telescoping assembly for transmitting hydraulic force to the drill bit at the bottom of the tool. The internal hydraulic characteristics of the tool may be varied to vary the force through extension and retraction of the telescoping assembly.

Abstract: The present disclosure is directed to a shock absorbing device for threading in a tubing string for running delicate instruments into a well borehole where they are in near proximity to explosives which might otherwise be detonate. This particularly is important in a well borehole which is filled with a standing column of liquid which transmits the shock waves quite readily. This is a separate assembly which can be threaded in the tubing string and has a pin and box connection for that. Moreover, it is formed of an outer mandrel surrounding connected inner upper and inner lower mandrels; the inner mandrels define annular spaces for receiving shock absorbers defined by alternating thin layers of metal and rubber; the metal and rubber washers have different shock wave impedances and tend therefore to absorb shock waves traveling either upwardly or downwardly in the well borehole.

Abstract: A telesciopic bar of drill rig for drilling in general, where the telescopic sections (10, 11, 12) consist of concentric, substantially cylindrical pipes, each of them equipped with longitudinal internal (16,17) and external (13,14) toothed ribs arranged in such a way that the external rib of each pipe and the internal one of the external pipe are engaged when the bar is being rotated to lock the telescopic sections in position, and released when the bar is being rotated in the opposite direction to lift and withdraw the bar sections.

Abstract: A telescopically extensible drill comprises a drill barrel, a drill bit connected to the barrel, and a drill rod which can be displaced between two longitudinally spaced positions in relation to the drill barrel, and secured in either of those positions. The drill can thus be extended in length without having to splice additional barrels or rods to the drill.

Abstract: A shock absorber device for inclusion in a tool string to provide rapid shock dissipation for shock forces traveling up or down the string. The device includes a tubular mandrel and an outer casing that forms an annular chamber therearound. At least one annular piston and one or more metering sleeves are formed integral with the outer casing and function to divide the annular chamber into a plurality of annular chambers that are filled with either nitrogen gas or silicone oil under selected pressures. Thus, the mandrel supports the lower tool string resiliently due to the fluid supported annular pistons such that any shock wave traveling along the tool string will be rapidly dissipated at the fluid piston interfaces.

Abstract: A shock absorber is adapted to be disposed within a perforating gun string or within the tubing string above the perforating gun and includes an energy absorbing element adapted to absorb and store mechanical energy during detonation of the perforating gun and to permanently deform in response to the storage of the mechanical energy, the stored energy being released in the form of heat, and not in the form of kinetic energy. Therefore, following absorption of the mechanical energy by the shock absorber, no further expansion of the shock absorber is experienced. The shock absorber includes an inner housing, an outer hosuing, a connection for interconnecting the inner and outer housing, and a break up charge for breaking the connection and releasing the inner housing from the outer housing when the perforating gun is detonated whereby the shock absorber is as strong as the tubing string before the connection is broken and is flexible after the connection is broken.

Abstract: A tool head is separably attached to the end of a hollow well drilling string for cutting operations within a well and for detachment of the cutting head from the string without removing the string from the well. The head is attached by a ball clutch structure having a pressure responsive release mechanism responsive to an actuating pressure on the release mechanism to release the cuttiong head and the release mechanism from the string, the release mechanism having an upwardly open passage and a downward flow permitting check valve for passing cutting fluid from the string through the passage to the cutting head. Release is effected by dropping a sealing member down the drill string to close the passage and by an increase in fluid pressure above the sealing member and the release mechanism.

Abstract: Apparatus for altering the length of a down-hole tool assemblly is described. The apparatus comprises a main housing (1), a slide (13) movable within the housing between a retracted position and an extended position, and latching means (6,755,33,41) to releasably secure the slide (13) to the housing (1) when the slide (13) is in either the extended position or the retracted position. The latching means (6,7,33,41,55) is activated and de-activated by fluid pressure within the apparatus where the apparatus forms part of a drill string, the fluid is typically drilling mud which is pumped through the drill string and the apparatus and the pressure is changed by changing the rate of mud flow through the drill string.

Abstract: Face shock absorber for extracting core-collecting pipes used for the drilling of solid mineral resources, which is incorporated in the drilling unit above the rock-breaking tool. It comprises a housing, the opposite ends of which are connected to a top and a bottom adapter, respectively. The top adapter is threadably connected to the top of the housing, the bottom end of which is provided with face fingers which interdigitate with the face fingers of the bottom adapter, formed in its top end. The bottom adapter is connected via an internal thread in the bottom end to a rock breaking tool inside the housing there are disposed external spring rings and internal spring rings which form a cylindrical spring pack, the top end of which is in contact with the top adapter, while its bottom end is in contact with the top face of a spacing sleeve, which is seated on the top face of a carrying collar forming part of the bottom adapter.

Abstract: A shock absorber apparatus for inclusion in a tool string which consists of outer and inner casings telescopically assembled with one casing having an uphole threaded joint member and the other casing having a downhole threaded joint member. The concentric casings then define spaced, sealed voids communicating through a metering sleeve clearance that are filled with a compressible oil. Shock wave induced relative movement of the casings from either direction causes a shock absorbing instantaneous displacement of oil from one void to the other via the metering clearance. Alternatively, coil springs may be disposed in the voids to aid in shock absorption.

Abstract: A soil sampling device and a sample containment device for containing a soil sample is disclosed. In addition, a method for taking a soil sample using the soil sampling device and soil sample containment device to minimize the loss of any volatile organic compounds contained in the soil sample prior to analysis is disclosed. The soil sampling device comprises two close fitting, longitudinal tubular members of suitable length, the inner tube having the outward end closed. With the inner closed tube withdrawn a selected distance, the outer tube can be inserted into the ground or other similar soft material to withdraw a sample of material for examination. The inner closed end tube controls the volume of the sample taken and also serves to eject the sample. The soil sample containment device has a sealing member which is adapted to attach to an analytical apparatus which analyzes the volatile organic compounds contained in the sample.

Abstract: An adaptor for drilling strings has a head, sleeve and mounting block assembly to secure a drill bit to a drilling string. By reverse rotation of the drilling string, the sleeve is movable between a first position, where pressurized air from the drilling string is directed to the drill bit, to a second position, where the air is directed to the drill hole above the adaptor to clear debris from the hole. Teeth at both ends of the assist the adaptor to clear the hole as the drill drill string is rotated and retracted from the hole.

Abstract: Apparatus including a rotary drilling cutter and a spoil removal conduit for the digging of a deep trench, characterized in that the spoil removal conduit is gradually adjustable in length during excavation and comprises: (a) a first conduit section, arranged proximate to said rotary cutter, and comprised of associated slidingly adjustable rigid male and female telescopic tube elements; (b) a second conduit section comprising a flexible tube having two ends, said flexible tube being connected to said first conduit section by one of its ends, its other end being disposed in the vicinity of the ground at a predetermined spoil discharge point, (c) a pulley supporting said flexible tube between said two ends; (d) lifting gear for suspending said pulley; and (e) a first cable associated with said lifting gear for supporting said pulley at selected adjustable heights.

Abstract: A reverse circulation drill rod of the dual tube type having a pin and box at opposite ends with a floating inner tube concentrically situated, the inner tube permitted longitudinal freedom of movement. A plurality of inwardly protruding radial directed lands adapted to encompass and align the inner tube are contained within each box and pin. Compression springs attached to the inner tube residing interiorly to the outer tube provide the longitudinal freedom of movement within limits. As the sections of drill rod are assembled vertically during operation, freedom of lengthwise movement by the inner tube allows stacking of the inner tubes in order that a seal be achieved between the square ends of each inner tube section. Compressed air or liquid is forced down the cylindrical space annulus formed between the outer tube and the inner tube, and drill bit grindings or rock fragments, together with the fluid, is brought to the ground surface in the conduit provided by the inner tube for simultaneous analysis.

Abstract: A manually operated downhole for an underground earth boring apparatus having a pneumatically operated earth boring tool. A drill pipe is connected to the tool and to a source of pneumatic fluid. A valve is positioned in the drill pipe substantially adjacent to the tool between the tool and the source of pneumatic fluid. This downhole valve controls the flow of pneumatic fluid to the tool. The valve is operable in response to pushing or pulling on the drill pipe.

Abstract: A drill string apparatus for the controlled absorption of both axial and torsional forces exhibited on the well string during drilling operations. The device is adapted to be connected in the drill string above the drilling tool in order to control the forces acting on the bit and to arrange the mean weight on bit for the selected drilling operation. Generally, the apparatus includes an outer casing coupled at its upper end to the drill string and an inner assembly telescopically received within the outer casing and connected at its lower end to the lower part of the bottom hole assembly or the drilling tool. Rotational torque is transferred from the drill string and outer casing to the inner assembly and drill bit by a series of helical splines. The mean weight on bit is controlled through an interchangeable pressure control nozzle mounted at the top of the inner assembly.

Abstract: A latch for a telescoping drill string jar is confined in an opening in the jar housing and engages the arbor of the jar to prevent telescoping action for normal drilling. The latch has a number of spring bars, each with a latch lug extending into a latch groove in the arbor. The lugs and the groove have beveled engagement surfaces that urge the spring bars radially outward, into clearance provided, when axial forces on the arbor relative to the housing exceed a preselected amount. The end of the spring bars are restrained in a cup with tubular sides extending along the spring bars to limit the length of spring bar allowed to flex radially outward. The length free to flex determines the average axial force required to release the latch. The ratio of the extending sides of the opposed cups determines the ratio of tension or compresive axial forces required to release the latch. The jar fitted with the latch is free to telescope, to cause jarring, when the lugs clear the groove.

Abstract: In a percussion drilling tool, a bit is connected to a drill motor through a mating spline connection. External splines on the bit engage internal splines in the drill motor and have respective load bearing faces disposed in a plane extending radially outwardly from central axes. The splines also include a crest land, and a root land. When the splines are in an abutting centered position, there is a uniform radially measured outer clearance between the external spline crests and the internal spline roots, and a uniform radially measured inner clearance between the external spline roots and the internal spline crests. The outer clearance is less than the inner clearance to prevent abrasive damage below the root diameter of the bit resulting from axial relative movement so that the external spline crests will engage the associated internal spline roots while continually maintaining a spacing between the external spline roots and the internal spline crests.

Abstract: An energy accumulator for use with a well pipe string to enhance the jarring impact delivered to an object stuck in a well bore by an up and/or down jar mechanism includes inner and outer telescopically connected members relatively movable longitudinally to accumulate energy in a mechanical spring arrangement, gas or compressible liquid in the accumulator. Cooperating surfaces on the inner and outer members of the energy accumulator assure that the jarring impact of the jar mechanism members is delivered to the stuck independently of the tensile or compressive load applied to the object jar mechanism and independently of the load rate of accumulating energy in the energy accumulator.

Abstract: A downhole drilling motor is disclosed in which an output shaft is allowed to translate in axial direction relative to the motor housing over a predetermined stroke. Fluid pressure of a drilling fluid pumped to a rotary drill bit driven by the motor may be used during operation of the motor to exert a predetermined axial force to the output shaft so as to control the axial force exerted to the bit during drilling.

Abstract: An accelerator for a fishing jar is disclosed. The accelerator includes front, compression, rear, and air chambers. These chambers insure that the pressure of the fluid in the compression chamber is substantially independent of the temperature of the fluid and the hydrostatic pressure of the well. These chambers also insure that the high pressure seals of the compression chamber are lubricated on each side of each seal. The accelerator also insures that a threshold upward force which is proportional to the hydrostatic pressure must be applied to the drill string before the fluid in the compression chamber begins to be compressed, thereby providing an accelerator that has a higher maximum load in deep wells.

Abstract: A drill string is rotated by a top drive system and includes a floating sub which interconnects the upper end thereof with the drill pipe, and a bit at the lower end thereof. The bit is connected to the lower end of the drill pipe by means of a shock absorber. The floating sub prevents vibrational energy from the drill string from damaging the top drive system while the shock absorber prevents vibrational energy from damaging the bit and vice versa.

Abstract: An apparatus for use in energy exploration is disclosed which is used where a radially expanding device is required, for example in a stabilizer, retriever or an underreamer. The apparatus comprises a support tubular member for connection to a drilling string, the member supporting a movable member which is axially movable along the member. A further member which may either be fixedly secured or also axially movable along the member is axially spaced from the movable member. The movable member and, optionally, the further member have tapered outer surfaces which cooperate with a taper on a radially movable member. The arrangement is such that movement of the movable member in the axial direction is such that the cooperating tapers cause the radially movable member to expand or contact in the radial direction. Various means for securing and performing radial movement are disclosed.

Abstract: Disclosed is a means for retaining drill chucks for down hole drills including a circumferential groove cut in both the drill chuck and the wear sleeve, into which it is inserted, in complimentary mating orientation whereby the circumferential groove forms a channel which is filled with ball bearings, for example through access ports provided in the wear sleeve. The ball bearings prevent uncoupling and may be removed readily thereafter permitting removal of the chuck.

Abstract: A drilling tool having a body that functions as a length of drill string and telescopes to shorten the body each time column load is applied by way of applied bit load. The telescoping action causes a cam turret in the body to change position to cause one of two possible conditions to exist while drilling. In one condition the body centerline is held straight while drilling. In the second condition the lower portion of the body is laterally deflected for changing the course of the well bore while drilling proceeds. Optional features cause a mud pressure signal to be generated, for detection at the surface, when selected elements in the apparatus are in preselected positions.

Abstract: An ice auger includes a pair of ice boring blades fixedly attached to the bottom of a straight inner auger drive bar. A brace and bit arrangement at the top of the drive bar is for rotating the drive bar and either forcing it down toward the ice to bore a cylindrical hole of predetermined diameter through the ice or to force it up away from the ice after the hole has been bored to ream out a portion of that hole to form an inverted funnel shape opening. A tubular outer sleeve surrounds the drive bar and is movable between an upper boring condition and a lower reaming condition with respect to the drive bar. Two slotted longitudinally extending ice reaming blades are pivotally mounted at their top portions to the ream control sleeve. A reaming blade camming support bar attached to a bottom portion of the drive bar carries camming pins slidable in the reaming blade slots.

Abstract: A vibration isolator and shock absorber system which provides excellent protection to sensors against the deleterious effects of shock and vibration even under severe drilling conditions is presented. The vibration isolator and shock absorber system is enclosed within an outer cage and an inner yoke. The cage is attached to the drill collar which takes the full impact of the shock and vibration due to drilling. The yoke supports the sensor. Conical disc springs (e.g. Belleville springs) or the like are stacked between the yoke and the cage; and are supported by pairs of upper and lower support rings. These rings fit together to compress the springs and to allow for axial displacement as well as providing damping. The pairs of support rings are supported, in turn, between upper and lower elastomeric isolator rings. The upper elastomeric isolator ring is keyed to the yoke and the cage. Fluid is allowed to move through the system via orifices in both the elastomeric isolators and the pairs of support rings.

Abstract: A face shock absorber with a top and a bottom adapter, between which there is mounted a housing, and in it there are disposed a spindle and active elements disposed inside a chamber enclosed by a top and a bottom disk, the housing and the spindle, and underneath the bottom disk there are disposed springs. The top adapter is embraced by a two-stepped nut with external thread, screwed up to the housing, and through the two-stepped nut there pass keys. The working chamber is divided by intermediate sleeves into sections, in each of which there are disposed spherical heads, shaped in the external surface of the spindle. The active elements disposed inside the working chamber are balls. The springs are limited in their bottom end by a ring-shaped nut, and it is possible to use springs of the slotted type.

Abstract: A borehole drill construction comprising a cylindrical casing, a chuck mounted on one end of the casing by means of a screw-thread and a cutter head carried by the chuck. The chuck has at least one axially projecting dog thereon which is received in a corresponding recess in the cutter head to provide a means to transmit torque from the casing to the cutter head via the chuck. The cutter head is retained on the bit by at least one plug projecting into a slot in the cutter head, which is permitted limited axial movement thereby.

Abstract: A floating cushion connection member is operable between a power head and a drill string member. A first cap member is mounted about the periphery of a piston. A washpipe extends from within the bore of the piston to a mounting area in a second cap member. A body member connects the first and second cap members. A spline member in the form of drive pins located between the body member and the piston rotate the piston with the body member and second cap member and allow the piston to move axially relative to the body member and the second cap member. The washpipe has limited angular movement within the second cap member and the piston. Cushion members are provided between the second cap member and the piston and the piston and the first cap member, respectively.

Abstract: A drilling apparatus has a rotatable drilling rod (15) on the leading end of which is mounted a bit assembly including a bit (10) and a bit driver (12) for reciprocating the bit. The bit driver is powered by a high pressure fluid supplied from a fluid pressurizing apparatus interposed between the rod and bit assembly and including a device (16,18/114) for raising the pressure of fluid in a closed circuit into which said bit driver is connected, the said device being driven from a power source remote from it, for example, on the surface of the ground in which a hole is being drilled.

Abstract: A slip joint for use in a well string and having a removable torque transmitting key. The slip joint includes an outer female mandrel having a central opening therethrough in which is slidingly positioned a male mandrel, also defining a central opening therethrough. In one embodiment, the male mandrel defines at least one longitudinal slot therein and the female mandrel defines a transverse opening therethrough adjacent the slot. The torque transmitting key is positioned in the transverse opening and extends into the slot. In the second embodiment, the inner mandrel includes a flat surface thereon and the outer mandrel has a longitudinal slot therein adjacent the flat surface. The key includes a ring portion having a flat surface therein engageable with a flat surface on the male mandrel and a lug portion extending from the ring portion into the slot.

Abstract: The present invention includes devices for absorbing shock in a tool string within a borehole. These components may serve together in a variety of configurations to form a shock absorbing system. A longitudinal shock absorber is connected in the tool string. The longitudinal shock absorber includes compressible members utilized to damp longitudinal movement. A radial shock absorber is connected in the tool string. The radial shock absorber includes resiliently mounted contact pads for contacting the sides of the borehole to damp radial movement. A carrier assembly is utilized to provide a shock absorbing mounting for particularly delicate components such as gauges, and to damp any shock which might be transmitted thereto from either a radial or longitudinal direction.

Abstract: A transformable circulation tool for reversing the path of drilling fluid at the drill bit without removing the drill string from the borehole annulus is provided by a substantially hollow body having a chamber with external ports disposed between a section of the body having a through passage and a by-pass passage in combination with a diverter mounted on a telescoping member having means for engaging the body during drilling and disengaging the body for rotation of the diverter with respect to each of the passages. A seal is rotatably mounted to the substantially hollow body between the ports to divide the well borehole into an upper conventional flow portion and a lower portion where the flow of the drilling fluid can be reversed upon command from the surface.

Abstract: The invention provides an adaptor which comprises a hexagonal tail portion adapted to engage in a drilling machine, and a leading portion which is adapted to receive a circular drill rod in locking relationship. Sealing means is provided between the drilling machine and the adaptor and the latter and the drill rod.

Abstract: A joint device in extension drill equipment for percussive drilling is so constructed that, besides transmitting compressive pulses in the drill string in the direction towards the drill bit, it also by reflection transforms tensile pulses in the drill string into compressive pulses. Preferably, the joint device includes members that are axially movable relative to each other and provided with interacting surfaces, and an element connecting the members. Compressive pulses cause these surfaces to abut each other under pressure, while tensile pulses cause the surfaces to become separated. Also preferably, the joint device includes a structure for absorbing kinetic energy generated in the device by torsion pulses in the drill string.

Abstract: The longitudinal position of an inner barrel within a core barrel assembly can be adjusted and locked in the field without necessitating the disassembly of the cartridge cap assembly within the core barrel tool, and therefore without entailing loss of expensive rig time. The inner tube is coupled through a swivel assembly to a cartridge cap. The cartridge cap is threadedly coupled to the coring tool, and in particular to the outer tube. Thus, the cartridge cap is arranged and configured to be rotated, and thus longitudinally adjusted with respect to the outer tube. An upper portion of the cartridge cap is provided with a plurality of radially expanding fingers. A jam nut is disposed within a cylindrical array formed by the fingers, and is threadably engaged with the inside surface of the fingers.

Abstract: A device is disclosed which is to be incorporated into a drill string used for drilling in subterranean formations. The device includes a first member concentrically mounted with drill pipes disposed above the device and a second member concentrically mounted with drill collars or drill pipes disposed below the device. An intermediate member connects the first and second members and a retainer member maintains the device in its first operative position wherein the entire device is concentric with the longitudinal axis of the drill string. In the first operative position of the device rotation can be transmitted from the first member to the second member and the device acts as an ordinary member of the drill string. The first, second and intermediate members are configured to be capable of occupying a second operative position relative to one another wherein the first member is off-center relative to the second member and wherein the first member does not rotate the second member.

Abstract: A stabilizer for use in drilling and having its effective outside diameter adjustable by alteration of axial forces applied to the stabilizer during drilling.

Abstract: A vibration dampener for use on top-drive rotary drills. The apparatus of the present invention comprises a generally cylindrical housing having a cylindrical side, a top, a bottom, and a central divider plate. The top of the housing has an externally threaded bore therethrough which may be connected to the rotary drive of the drill. A central, coaxial tube is slidably received within the housing. The downward end of this tube may be connected to the drill pipe, and the tube thus provides a conduit through which air may be forced.A generally circular compression plate is connected within the housing to the central tube so as to be adjacent and substantially parallel to the bottom of the housing. A resilient pad is positioned between the compression plate and the central divider plate such that an upward force on the central tube causes the compression plate to be lifted and the resilient pad to be compressed between the compression plate and the divider plate.

Abstract: A telescopic shock absorber for use in a drill string includes a resilient arrangement to cushion telescopic contraction and extension of the shock absorber in response to shock loads and vibrations imparted during drilling. The shock absorber operates independently of the drilling fluid pressure conducted through the structure during drilling operations. A dampening system assists in cushioning the shock loads and vibrations and the dampening system and resilient arrangement are deactivated when jarring impacts are delivered to the well string by a drilling jar carried therein. The resilient arrangement provides a combination mechanical and hydraulic system for cushioning the impact loads and vibrations encountered.

Abstract: An adjustable length drilling sub is disclosed for placing in a drill string between stabilizers to allow the distance between the stabilizers to be changed while the drill string is in the well bore to adjust the rate the angle of the well bore from the vertical is changing. The sub includes an outer member and an inner member that extends into the outer member with an annular space between the members. Protrusions in the form of drive pins mounted in the wall of the outer member extend into the annular space to move into and out of engagement with cavities formed on the outer surface of the inner member. When the pins are in engagement with the cavities, torque in one direction and weight can be transmitted to the bit. When the pins are rotated in the other direction out of the cavities, the members can be moved longitudinally relative to each other to change the distance between the stabilizers.

Abstract: The present invention comprises a pressure balanced tubular spring slip-joint and jar including a generally tubular outer housing having longitudinal slot means in the wall thereof, and a hammer area of increased wall thickness at one end thereof, within which housing slidably extends a jar mandrel means having first and second longitudinally spaced enlarged diameter anvil areas, at least one fastener tapped into one of those anvil areas, the heads of said fastener protruding into said slot means. Both said housing and said mandrel means possesses axial bores therethrough, which are placed in communication via the bore of a tubular spring within the housing, whereby during extension and contraction of the slip-joint and jar means of the present invention the area within said axial bores and said spring bore is of a constant volume.

Abstract: A tool for improving drill bit penetration in the drilling of oil, gas and water wells and the like is provided. The tool includes a housing and a mandrel connected for co-rotation and limited axial movement under the influence of a spring fluid. The mandrel and drill bit in conjunction with the spring fluid form a spring-mass system having a damped fundamental frequency of oscillation approximately equal to a characteristic frequency of forces (F.sub.2) which act on the drill bit during drilling. Resonance causes the forces acting on the bit (F.sub.2) to be amplified and magnified, thereby increasing the drilling rate.

Abstract: For use in a well jar, a mounting apparatus for resilient elongate snubbers is described. In the preferred and illustrated embodiment, parallel elongate resilient snubbers are formed on metallic backing strips. They are profiled to define sloping elongate sides which slidably fit within undercut grooves. The undercut grooves extend from an encircling shoulder to enable easy insertion into the grooves. The shoulder is adjacent to an encircling narrow neck, thereby enabling an expandable lock ring to be positioned in the neck, securing the resilient snubbers in position.

Abstract: An oil field jar includes a barrel and mandrel selectively interconnected by a ball transfer mechanism so that pulling upwardly on the jar causes a ring spring assembly to be stressed. As the spring assembly reaches its limit of stroke, the ball transfer mechanism trips so that the mandrel moves relatively freely with respect to the barrel. A hammer and an anvil carried by the mandrel and barrel then impact to create an upwardly directed jar on the fish to which the tool of this invention is connected. The ball transfer mechanism includes a plurality of balls which move both axially and radially of the tool during operation.

Abstract: A replaceable insulating sleeve is disposed around the lower end of a drill string used in drilling a well. The sleeve is restrained from rotating relative to the drill string, but can be released and quickly slipped off the drill string in the field to permit rapid replacement if damaged, or if alternate equipment is required. The sleeve carries sensing means for measuring a characteristic of formations penetrated by the well.

Abstract: A drill assembly or auger for forming a hole in a surface such as ice and having a readily extendible and retractable shank assembly. The shank assembly has first and second longitudinal shank members. One shank member is telescopically engagable in the other shank member and moveable between a first relatively retracted configuration of the shank assembly and a second relatively extended configuration of the shank assembly.First and second coupling members are located at longitudinally spaced intervals on said shank assembly for coupling the shank member having cutting means to the shank member with operating structure upon operation of the operating structure to rotate the shank assembly in a direction to form a hole selectively in the first and second positions respectively.The coupling members are releasable for telescopic movement of the shank members between positions by rotation of the shank member having the operating structure in a direction opposite that necessary to form a hole.