Abstract: A power transmission shaft has a shaft member having, on an outer peripheral surface thereof, a male spline; a cylindrical member having, on an inner peripheral surface thereof, a female spline; and a seal member provided in a pressed state between an outer peripheral seal surface formed on the outer peripheral surface of the shaft member and an inner peripheral seal surface formed on the inner peripheral surface of the cylindrical member. The cylindrical member is spline-engaged with the shaft member by one end side of the shaft member being inserted into the cylindrical member from an other end side of the cylindrical member. Axial direction shock is absorbed by sliding of the splines. The outer peripheral seal surface is positioned at the other end side with respect to the male spline, and the inner peripheral seal surface is positioned at the other side with respect to the female spline.

Abstract: The present application relates to self-adjusting damping vibration absorbers, in particular to a self-adjusting damping vibration absorber for while-drilling instruments and an adjusting method thereof. The self-adjusting damping vibration absorber includes a vibration monitor and controller tool and a vibration absorber body. The vibration monitor and controller tool is mounted inside the downhole while-drilling instrument, one end of the vibration absorber body is connected to the vibration monitor and controller tool through an insulating connector, the joint is provided with an insulating pad, the other end is connected to a sensor or circuit board tool that needs vibration damping, and the inside of the vibration absorber body is provided with a damping adjustment layer made of an electroactive polymer. By controlling the magnitude of an applied voltage, the damping adjustment can be realized, and the damping adjustment layer has the characteristics of high response speed and high control precision.

Abstract: Methods and systems for damping torsional oscillations of downhole systems are described. The systems include a downhole string, a bit support assembly configured to support and receive a disintegration device, wherein the disintegration device is disposed on an end of the downhole string and mounted to the bit support assembly, and a damping system configured at least one of on and in the bit support assembly, the damping system comprising at least one damper element arranged in contact with a portion of the bit support assembly.

Abstract: A shock isolated gamma probe attenuates axial, lateral, and torsional shocks to a gamma sensor package. A gamma sensor is inserted into and fixed to a tubular cartridge. The cartridge is closed with a cap and keyed at the other end. The cartridge is inserted into a resilient sleeve having an extension at the closed end to conform to the key on the cartridge. The open end of the resilient sleeve is closed with a gasket. The sleeve/cartridge assembly are inserted into a tubular structure on a first chassis. The first chassis has a keying structure for the key and extension of the resilient on an end bulkhead. The cartridge and first chassis are resiliently engaged to attenuate shocks. A second bulkhead, on a second chassis, closes the open end of the tubular structure on the first chassis.

Abstract: A device, such as a snubber or shock absorber, for mitigating shock and vibration in downhole tools is provided. The device can have a body and an insert, which are separated by an elastomer to inhibit direct metal-to-metal contact therebetween. The insert has a projecting portion located within a cavity of the body. The elastomer is disposed within a gap between the insert and the internal surface walls of the cavity, and the elastomer surrounds and contacts the projecting portion and the walls. The elastomer may be molded, for example by flowing it into the cavity and subsequent hardening. Injection holes may be provided for molding. The projecting portion may be shaped to limit rotation upon failure of the elastomer and/or may include ribs and splines for shock absorption. The body may include a cap that contains the projecting portion to inhibit pull-apart.

Abstract: A stump cutting assembly mounted to a stump cutting wheel. Stump cutting assembly is a stump cutting tooth interconnected to the wheel by a holder or block that is fixed to wheel by welding or other equivalent process, an optional debris deflector and a fastener that interconnects tooth and deflector to holder. As wheel rotates about its axis of rotation, the tooth cuts away at wood or other debris in which it comes into contact through the side to side and/or longitudinal movement of a stump grinder unit.

Abstract: A drill bit with fixed cutter elements with a hollow upper conical pin connector connectable to the lower module of a drill string, where the upper conical pin connector has a transition to an upper cylindrical module with a central channel for supplying bore fluid from the drill string, equipped with, a lower bore holding a cylindrical socket from the lower module, connecting the upper and lower modules of the drill bit, where the central channel continues down through the lower module and branches out into nozzle channels with nozzles ending in the recesses in between the wings with fixed PDC-cutters, wherein elastic shock-absorber elements are arranged in recesses in the cylindrical wall of the bore, in the upper cylindrical module, and the elastic shock-absorbers are assembled on the bolts extending into the cylindrical socket of the lower module.

Abstract: Shock tools can include a rotary top drive box in threaded connection with an outer tube. A center plate tube can run through the center of the shock tool to provide a pathway for drilling fluid and/or mud to flow to the drill bit. A bottom tube socket box holding head can be attached to the outer tube and the center plate tube can be connected to a bottom drive socket. The bottom tube socket box holds a portion of the bottom drive socket within the outer tube. The center plate tube can be slidably engaged with the rotary top drive box. Multiple compression plates separated by compression pads are located in the tool to dampen the shock load by distributing the load across each of the multiple pads, thereby minimizing the load on any individual pad. This arrangement allows for higher load dampening lower failure rates.

Abstract: Apparatus and methods for controlling drill string vibrations and applying a force to a drill bit include a body having a first piston at an uphole end in association with a drill string and a second piston at a downhole end in association with a drill bit. A first biasing member urges the first piston outward to provide a first force in an uphole direction to the drill string. A second biasing member urges the second piston outward to provide a second force in a downhole direction to the drill bit. When vibration from the drill string compresses the first biasing member, the first force resists the vibration and maintains the apparatus and drill bit in a consistent orientation. When an uphole force from the drill string or the drill bit compresses the second biasing member, the second force prevents movement of the drill bit in an uphole direction.

Abstract: A drilling tool that has a flexible shaft so as to be able to make short radius curves while still being able to transmit torque and axial loads. The drilling tool includes a drill shaft for transmitting axial load, comprising a series of coaxial ring members connected together such that adjacent ring members are flexible in an axial plane relative to each other; each ring member being connected to an adjacent ring member by connecting member arranged to transmit torque therebetween; and axial supports extend between adjacent ring members so as to transmit axial loads therebetween.

Abstract: A drillpipe for a drill stem to drill a hole. The drill stem includes a drill string and a bottom hole assembly. The drillpipe includes a first end having a first inertia, a second end having a second inertia, a first intermediate zone adjacent to the first end, a second intermediate zone adjacent to the second end, and a central substantially tubular zone with an external diameter smaller than the maximum external diameter of at least the first or the second end. A casing is fixed on the pipe over a portion of the external surface thereof, at least one physical parameter sensor is disposed in the casing, and at least one data transmission/storage mechanism is connected to the sensor output, the casing being disposed at a distance from the first and second ends, the casing being integral with the central zone at a distance from the first and second intermediate zones and having a smaller inertia than the first and second inertias.

Abstract: A drilling tool steering device includes, consecutively from upstream to downstream, a main body (1) and a steerable housing (2); a deflection system (7); and a flexible transmission shaft (3). The transmission shaft crosses the main body, the steerable housing, and the deflection system longitudinally, is bendable or flexible, and is connected to the main body (1) and to the steerable housing (2) by at least three connections forming bearings (4, 5, 6). Steering is carried out by the deflection system (7) acting by an essentially radial relative displacement of the main body (1) in relation to the steerable housing (2) in proximity of their interface.

Abstract: An axially-floating sub tool for axial load compensation in conjunction with a top drive comprises cylindrical upper and lower members, with the upper member being coaxially disposed within a cylindrical housing. The upper member has an upper section slidably disposed within an opening in the upper end of the housing, plus a middle section that slidably and sealingly engages the housing bore. The lower-member bore has a splined upper interval, and a coaxial stinger extending upward from an annular shoulder medially located in the lower-member bore. The lower member is connected to the lower end of the housing with the stinger slidingly and sealingly disposed within the upper-member bore, and with the lower-member splines slidingly engaging the upper-member splines, thus defining upper, middle, and lower annular chambers, with the middle and lower chambers in fluid communication, and with a regulator/check valve regulating pressure in the middle and lower chambers.

Abstract: A cushion sub-assembly (10) for connection to a drill string to absorb vibrations in the drill string, the cushion sub-assembly (10) including a main body (12) defining a chamber therein (24), a piston member (28) disposed within the chamber (24) capable of axial movement at least partially within the chamber (24) between a first and second position, at least one axially extending piston rod (42) disposed inside a respective axial bore of the piston member (28), the at least one piston rod (42) preventing relative rotation between the piston member (28) and the main body (12) while permitting axial movement of the piston member (28) between the first and second positions, and a vibration absorbing means (44, 46, 48, 50) at opposite ends of the chamber (24) for engagement by the piston member (28) when in either of the first or second positions for absorbing axial vibrations, the configuration of the at least one piston rod (42) inside the piston member (28), and engagement of the piston member (28) with the v

Abstract: A drilling tool that has a flexible shaft so as to be able to make short radius curves while still being able to transmit torque and axial loads. The drilling tool includes a drill shaft for transmitting axial load, comprising a series of coaxial ring members connected together such that adjacent ring members are flexible in an axial plane relative to each other; each ring member being connected to an adjacent ring member by connecting member arranged to transmit torque therebetween; and axial supports extend between adjacent ring members so as to transmit axial loads therebetween.

Abstract: A drilling tool that has a flexible shaft so as to be able to make short radius curves while still being able to transmit torque and axial loads. The drilling tool includes a drill shaft for transmitting axial load, comprising a series of coaxial ring members connected together such that adjacent ring members are flexible in an axial plane relative to each other, each ring member being connected to an adjacent ring member by connecting member arranged to transmit torque therebetween; and axial supports extend between adjacent ring members so as to transmit axial loads therebetween.

Abstract: Implementations of the present invention relate generally to methods, systems, and apparatus for absorbing vibration and shock impulses created during drilling operations. In particular, implementations of the present invention include drill-string shock absorbers adapted to absorb longitudinal forces produced during a drilling operation. For example, drill-string shock absorbers in accordance with at least one implementation of the present invention include a generally cylindrical housing having a first end and a second end coupled together by a radially interlocking joint. Such a configuration can reduce mechanical failure and increase the operating life of the shock absorber by transmitting torsional forces directly between the ends of the housing and reducing stresses from being transferred to fastening means securing the first and second ends of the cylindrical housing together.

Abstract: Systems and methods for preventing slippage and rotation of components installed along a rotatable tubular shaft and/or in a tubular housing member during drilling operations are disclosed herein. The housing and/or rotatable shaft include a shoulder disposed proximate to one end. An adjustable member is secured proximate to the opposite end. One or more components are installed, covering a first portion of the surface between the adjustable member and shoulder. One or more spacing members are installed to cover substantially all of the remaining surface. The adjustable member is tightened such that the adjustable member and the shoulder apply a compressive axial load to the components and spacing members, causing frictional forces between adjacent objects greater than the torque acting on the housing and/or tubular shaft, causing each component to remain stationary with respect to the surface to which it is secured.

Abstract: A sealing element including a tube-shaped body of metallic material and first and second male sealing members arranged at a respective end of the body. At least two intermediate members are arranged in series in the body between the first and second male sealing members. Each one of the intermediate members is compressible so as to be capable to store elastic energy when the body is subjected to axial compression and includes a protuberance arranged in the body and extending around the center axis of the body. A coupling device provided with such a sealing element.

Abstract: A shock-absorber subassembly for a subsurface drilling assembly is disclosed. The shock-absorber subassembly comprises a mandrel, a body assembly, and at least one torsional spring assembly. The mandrel has a bore extending therethrough and has one end connectable to a portion of the subsurface drilling assembly. The body assembly has a bore extending therethrough and one end connectable to another portion of the subsurface drilling assembly. The body assembly is coupled to the mandrel to establish fluid communication between the bore of the mandrel and the bore of the body assembly and to permit planar rotational movement of the mandrel relative to the body assembly. The at least one torsional spring assembly engages the mandrel and the body assembly to absorb torsional shocks and vibrations between the mandrel and the body assembly and to limit the degree of planar rotation between the mandrel and the body assembly.

Abstract: A drill bit comprises a shank member (31), a bit body (32) provided with cutters (33) and flexible material (35) between the shank (31) and the bit body (32) allowing relative tilting movement therebetween to reduce adverse effects caused by vibration of the bit. In other embodiments, flexible material is provided between the bit body and the cutters. In further embodiments, the flexible material may be provided in a tiltable sub-assembly for incorporation in a drilling above the drill bit. An apparatus for simulating drilling conditions is also provided.

Abstract: Flexible couplings are provided comprising a male member disposed within a female member in a spaced apart configuration, with the space being filled, at least partially, with an elastically deformable material. The male and female members comprise features that prevent separation from one another after the elastically deformable material is provided in the space between them. For example, the male and female members of one embodiment each comprise a threaded region, with the respective male and female threads being intermeshed but generally spaced apart from each other. At least one of the male and female threads is tapered in two opposing directions with respect to a coupling centerline. The double taper requires the elastically deformable material to be displaced for the male and female members to become separated. However, the elastically deformable materials are constrained by surfaces of the male and female members, and therefore, cannot be displaced.

Abstract: A torsional shock absorber dampens rotary shock loading on a well drill string. An outer housing has drive splines on an inner surface. A mandrel is located within the outer housing and has drive splines on an outer surface that fit between the drive splines on the inner surface of the housing. Dampening bars are positioned longitudinally between the splines of the outer housing and the splines of the mandrel to absorb shock from non-uniform torsional loading at the drive interface between the outer housing and the mandrel. A balancing piston is located within the tool to compensate for pressure difference between drilling fluid pressure and lubricant contained within the shock absorber. A thrust bearing assembly is provided to accept axial thrust loads from the outer housing and transfers the load to the splined mandrel. A retainer transfers tensile loads from the housing to the mandrel through the thrust bearing.

Abstract: A vibration damping apparatus including an annular housing, a cavity between an internal diameter and an external diameter of the housing, and a substantially solid vibration damping material disposed in the cavity. The vibration damping material has a density that is greater than a density of the housing material. In one embodiment of the invention, the internal diameter and the external diameter of the housing are selected so as to maximize an amount of vibration damping material with respect to a selected tensile strength for the housing. In another embodiment of the invention, the internal diameter and the external diameter of the housing are selected so as to maximize an amount of vibration damping material with respect to a selected bending strength for the housing.

Abstract: A cushion sub for absorbing both axial and torsional vibration in a drill string and including an outer casing connectable at one end to a section of a drill string, and an inner piston reciprocally mounted in a cylinder within the casing, the piston having a shaft projecting from the other end of the casing connectable to another section of the drill string. The cylinder includes a first cushion device at opposite ends thereof for engagement by the piston to absorb axial vibrations. A spline type connection prevents relative rotation between the piston and the cylinder. The cylinder is mounted for arcuate turning in a chamber within the casing, but the cylinder has vanes which are interposed between vanes fixed to the casing, and elastomeric material between the vanes of the cylinder and the vanes of the casing absorbs torsional vibrations being transmitted between the cylinder and the casing.

Abstract: A torque transmitting device for use with a rotary drill bit connected to a drill collar, comprises a first member connected to the drill collar, a second member connected to the drill bit, and coupling means connecting the two members together for rotation about a common central axis. The coupling means permits limited relative rotation between the members about the axis, but provides a resistance to rotation of the first member relative to the second member in a forward drilling direction which is greater than its resistance to relative rotation in the reverse direction. The comparatively lower resistance to rotation in the reverse direction prevents momentary reverse rotation of the drill collar, due for example to torsional oscillations, being transmitted to the drill. bit. This reduces the likelihood of damage to the cutters on the drill bit, which might otherwise result from such momentary reverse rotation of the bit.

Abstract: An elastomeric joint that can be used, as part of an articulated coupling in a progressive cavity device, including using the articulated coupling for converting the complex motion of the rotor into simple rotation. The coupling includes two shafts coupled to one another by coupling assemblies connected to opposite ends of an intermediate shaft. The coupling assemblies include interlocked threaded and tapered portions and an elastomer filling the spaces between the threaded portions. Under loading the male and female portion move relative to one another so that the elastomer is subject to both compression and shear. Should the elastomer fail, the threaded portions simply lock together thereby allowing fail safe operation. Provisions are also made to protect the integrity of the coupling under reverse torque. The moving components within the coupling are perfectly isolated from the surrounding environment.

Abstract: A device reducing the deleterious torque in a shock absorbing, rotary drive coupling unit used with a rotary mine drilling machine comprising: a drive plate connectable to a drive shaft of the rotary drilling machine, a driven plate connectable to a driven shaft which has a drill bit, a center portion for coupling the drive plate to the driven plate wherein the center portion includes a deformable shock, vibration and torque-absorbing member, and torque-relief means comprised of a first engagement member(s) connectable to the drive plate and a second engagement member(s) connectable to the driven plate. When the drill bit snags or jams during the operation of the rotary drilling machine, the torque-absorbing member deforms and absorbs some of the torque generated therefrom.

Abstract: A device reducing the deleterious torque in a shock absorbing, rotary drive coupling unit used with a rotary mine drilling machine comprising: a drive plate connectable to a drive shaft of the rotary drilling machine, a driven plate connectable to a driven shaft which has a drill bit, a center portion for coupling the drive plate to the driven plate wherein the center portion includes a deformable shock, vibration and torque-absorbing member, and torque-relief means comprised of a first engagement member(s) connectable to the drive plate and a second engagement member(s) connectable to the driven plate. When the drill bit snags or jams during the operation of the rotary drilling machine, the torque-absorbing member deforms and absorbs some of the torque generated therefrom.

Abstract: A shock absorbing assembly for a drilling machine utilizing a down hole hammer having a driver member for receiving input forces, a driven member for transmitting forces from the driver member to an attached drill string, and a resilient member which is placed under tension and elongated when downward forces are applied. The resilient member under tension receives and dissipates shocks and vibrations.

Abstract: A progressive cavity device including an articulate coupling for converting the complex motion of the rotor into simple rotation. The coupling includes two shafts coupled to one another by joint assemblies connected to opposite ends of an intermediate shaft. The joint assemblies include interlocked threaded portions and an elastomer filling the spaces between the threaded portions. Under loading the male and female portion move relative to one another so that the elastomer is subject to both compression and shear. Should the elastomer fail, the threaded portions simply lock together thereby allowing fail safe operation. The moving components within the coupling are perfectly isolated from the surrounding environment.

Abstract: A longitudinal and rotary vibration dampener or shock absorber for rotary and percussion drill bits comprises a resilient element to absorb axial compression loads, preferably in a compression mode; a resilient element to absorb axial tension loads, preferably in a compression mode; resilient elements to absorb torque loads in clockwise and counterclockwise directions preferably in a compression mode; radial guide surfaces for long wear between the driver and the driven members and preferably spaced apart axially to resist bending couple loads applied across the two members during operation; and a seal and surface to allow passage of air or other fluid through the unit during operation. All resilient elements, guide members, and seals are readily replaceable in the field. The unit is structurally sound and enclosed and is attachable to the drilling rig drive head and drill pipe or to the drill pipe and bit as the case may be.

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: 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 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: 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 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: 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 well tool carried in a drill string for maintaining bottom hole contact while absorbing angular and axial shock forces of a rotating drill bit. The tool has an elongated body with pipe joint ends and includes a tubular mandrel slideably mounted within a tubular barrel. A groove and roller connection guides the mandrel within the barrel during drilling. Resilient shock absorbing members between metal guide rings are carried between stop elements on the mandrel and barrel. Shock forces are absorbed by the telescoping movements of the mandrel within the barrel and by in the members acted on by the stop elements. The mandrel is formed of two pieces that threadedly connect to one another between the resilient shock absorbing members and the groove and roller connection. A lifting lug positioned above the rollers and below the shock absorbing members within an elongate mandrel groove, engages the joint to transfer the weight of the mandrel to the barrel upon withdrawal of the tool.

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: In a drilling operation fatique producing vibrational motion is produced in the drill string in the form of longitudinal and torsional load variations at the drill bit and throughout the bottom hole assembly. These load variations occur at least partially as a result of the irregularly shaped hole bottom which develops beneath the bit and which in turn cause the bit to rise and fall with rotation, and the bit loading to vary. In addition, the rotating drill string causes gyrations in the drill string which are transmitted to the bottom end of the drill string and drill bit in the form of load and torque variations. These variations in loading appear as longitudinal and torsional vibrations in the drill string. A dampening and shock absorbing mechanism is at least partially comprised of piezoelectric elements which are responsive to the vibrations of the drill string to produce electrical energy which is used to operate downhole electrical circuits.

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: A well tool carried in a drill string for maintaining bottom hole contact while absorbing angular and axial shock forces of a rotating drill bit. The tool has an elongated body with pipe joint ends and includes a tubular mandrel rotationally and slideably mounted within a tubular barrel. A groove (preferably helical) and roller connection guides the mandrel from the barrel during drilling. Resilient shock absorbing members between metal guide rings are carried between stop elements on the mandrel and barrel. Shock forces are absorbed initially by the rotating/telescoping movements of the mandrel within the barrel. Excess shock forces are absorbed in the members acted on by the stop elements on further inward/outward movements of the mandrel rotating in the barrel. Unique cross-over rings (graphite-filled Teflon.RTM.) cushion the resilient members from impacts of the metal guide rings.

Abstract: A shock absorber assembly adapted to be used with a drill string dampening intermittent shocks and vibrational forces encountered with a drill string, the shock absorber assembly including a mandrel, a tubular body reciprocally mounted with respect to the mandrel, and a dampening device including an annular chamber adapted to be filled with a compressible fluid and a flexible wall with the mandrel adjacent the annular chamber for permitting flexure of the mandrel as needed for dampening.

Abstract: A shock absorbing tool is provided for connection to a drill column. The drill column includes a drill bit and is positioned in a bore formed in the earth. The shock absorbing tool is an integral, resilient cylindrical member having a number of open sections formed in the cylindrical member. Pairs of open sections are interconnected by slots. Pairs of open sections are longitudinally spaced along the periphery of the cylindrical member. The longitudinal distance between pairs of open sections and the circumferential distance between open sections of each pair of open sections vary. Upon application of dynamic axial and torsional loads to the drill column, the shock absorbing tool absorbs these loads through deflection of the resilient tool such that the slots close and the stress produced by the dynamic loading is carried about the periphery of the open sections.

Abstract: A novel shock sub is disclosed for use in a drill string for absorbing longitudinal and impact loads. A tubular housing is provided for connection to one part of a drill string and a tubular mandrel extends into the housing for longitudinal sliding movement with an outer end portion for connection to the other part of the drill string. The mandrel and housing define an annular cavity when assembled. The mandrel has two slots, positioned 90.degree. apart circumferentially extending for length of the annular cavity. Annular spring washers positioned in the annular cavity are of a size having a sliding fit on the outside of the mandrel and inside the housing. The spring washers are each corrugated in a wave configuration and with a tab of a size fitting one of the mandrel slots and are placed on the mandrel with alternate ones having tabs fitting in one of the slots and the others having their tabs fitting another mandrel slot.

Abstract: A shock absorber assembly for absorbing shocks encountered by a drill string wherein the shock absorber assembly is for use with a drill string having a working fluid therein and includes a body member affixed to the drill string, a mandrel mounted for reciprocal longitudinal movement with respect to the body member and a fluid dampening member floated within the central bore of the body member in engagement with the body member and the mandrel for absorbing shocks transmitted between the body member and the mandrel.