Abstract: An attitude control device has a plurality of harmonic drive mechanisms of the hollow type, preferably first and second harmonic drive mechanisms. First and second rotational members are connected to the outputs of the first and second harmonic drive mechanisms. These rotational members have eccentric hollow portions which rotate eccentrically around the rotational axes of the harmonic drive mechanisms. A member to be driven is placed to extend through the eccentric hollow portions such that it is supportedly contacted with the inner surfaces of the eccentric hollow portions. In operation, the eccentric hollow portions are rotated relative to each other, whereby the member to be driven is controllably oriented to a desired direction.The attitude control device can be employed as a drillingdirection control device wherein a rotational drill shaft is supported by inner surfaces of eccentric hollow portions of first and second rotational members.

Abstract: An attitude control device has a plurality of harmonic drive mechanisms of the hollow type, preferably first and second harmonic drive mechanisms. First and second rotational members are connected to the outputs of the first and second harmonic drive mechanisms. These rotational members have eccentric hollow portions which rotate eccentrically around the rotational axes of the harmonic drive mechanisms. A member to be driven is placed to extend through the eccentric hollow portions such that it is supportedly contacted with the inner surfaces of the eccentric hollow portions. In operation, the eccentric hollow portions are rotated relative to each other, whereby the member to be driven is controllably oriented to a desired direction.The attitude control device can be employed as a drilling-direction control device wherein a rotational drill shaft is supported by inner surfaces of eccentric hollow portions of first and second rotational members.

Abstract: The drilling apparatus according to the invention contains a body (1) to which rock-destroying organs--rollers (2) are attached. A subassembly for generating hydrodynamic waves is arranged in the body (1). This subassembly is designed in the form of a turbulence chamber (3) with tangentially arranged entry channels (4) and with a conically tapering outlet channel (5) the frontal surface of which is radially rounded off.

Abstract: The specification discloses an apparatus for driving and/or pulling a pile which basically comprises vibratory device, a pulling device, a plurality of shock absorbing members, and shock connecting apparatus. The vibratory device generates a vibratory force and applies this force to the pile. The pulling device applies a tension load to a carrying member. The shock connecting apparatus is operatively connected to the carrying member, the shock absorbing members, and the vibratory device. The shock connecting apparatus so selectively connects each of the plurality of shock absorbing members between the vibratory device and the pulling device that the total shock absorbing capacity of the apparatus is incrementally increased as the tension load applied to the carrying member increases.

Abstract: A drilling bit having an irrigation system which uses an irrigating fluid. The bit comprises a hollow drill head 14 housing at least one fluidic oscillator 23, 23' which includes an accelerator nozzle 26, 26' supplied by said fluid and opening into a cavity 46, 46' in which a dividing element 34, 34' is mounted which is provided with a ridge 36, 36' located slightly downstream from the nozzle. Said dividing element defines in said cavity two passages 42, 44, 42', 44' towards which the fluid is alternately directed in pulsed jets. Said passages are linked respectively to two series of channels 16 to 22 which open onto the outer surface of the head 14 through a plurality of outlet openings 21 which are oriented so that the pulsed jets they give out are directed to selected portions of the head that need to be cleaned, cooled or lubricated.

Abstract: This invention relates to flow pulsing methods and apparatus for various applications including downhole drilling equipment and in particular to an improved flow pulsing method and apparatus of this type to be connected in a drill string above a drill bit with a view to securing improvements in the drilling process.

Abstract: Device for the auditory and/or visual representation of mechanical phenomena in the interaction between a drilling tool and rock being drilled, characterized by the fact that it includes a mechanism for picking up a vibratory signal representing the vibration of the tool at the cutting face using an accelerometric sensor at a specific point on the drilling stem and processing equipment (45, 31, 31) for filtering the signal in the frequency band of 10 to 200 Hz.

Abstract: A shock absorbing apparatus for a vibratory pile driving/pulling device having a base section connected to a vibrating device, a connecting section connected to a carrying member such as a lifting cable and an intermediate section operatively connecting the base section and the connecting section. First shock absorbing members are provided for resisting force of relatively small magnitude between the base section and the intermediate section and second shock absorbing members are provided for resisting force of relatively greater magnitude between the intermediate section and the connecting section. A limit stop is provided to limit the relative vertical displacement between the base section and the intermediate section such that the second shock absorbing members absorb much of the load when the apparatus is under a substantial external load.

Abstract: Vibrations in borehole equipment are controlled by defining the energy flow through the equipment as the product of an "across" variable and a "through" variable, wherein fluctuations in one variable are measured and the energy flow is controlled by adjusting the other variable in response to the measured fluctuations in said one variable. Suitable variables for defining the energy flow are voltage times current of an electrical drive, pressure times flow rate of a hydraulic drive, or torque times angular velocity of any rotary drive.

Abstract: This invention relates to flow pulsing methods and apparatus for various applications including downhole drilling equipment and in particular to an improved flow pulsing method and apparatus of this type to be connected in a drill string above a drill bit with a view to securing improvements in the drilling process.

Abstract: Flow pulsing apparatus is adapted to be connected in a drill string above a drill bit. The apparatus includes a housing providing a passage for a flow of drilling fluid toward the bit. A valve which oscillates in the axial direction of the drill string periodically restricts the flow through the passage to create pulsations in the flow and a cyclical water hammer effect thereby to vibrate the housing and the drill bit during use. Drill bit induced longitudinal vibrations in the drill string can be used to generate the oscillation of the valve along the axis of the drill string to effect the periodic restriction of the flow or, in another form of the invention, a special valve and spring arrangement is used to help produce the desired oscillating action and the desired flow pulsing action.

Abstract: A Moyno type oscillator having a screw shaped rotor and stator is lowered down by means of a cable within a section of drill pile which has become stuck in a bore hole. The rotor of the oscillator is rotatably driven by means of a liquid stream at a speed such as to generate vibrational energy in the oscillator housing at a sonic frequency. The cable from which the oscillator is suspended has swivel bearings installed therein to permit the oscillator housing to rotate from the cable. The vibrational energy generated in the oscillator housing causes the housing to rotate precessionally around the inside wall of the stuck section of drill pipe to thus generate amplified lateral quadrature vibrational energy in the drill pipe to shake it loose from the bore hole.

Abstract: A vibration dampening assembly, such as a dynamic balancing apparatus, is connected to a drill bit, a downhole motor or drillstring to exert a variable force to counteract vibration inducing forces. The dynamic balancing apparatus includes a support body which supports a plurality of freely movable masses so that the masses move to a position for opposing an imbalance force which rotates with, and at the same speed as, the drill bit, downhole motor or drillstring.

Abstract: A sonic boring tool which employs sonic energy in implementing its boring action is lowered down a well to a region thereof where the flow of effluent is restricted by clogging and contamination. A curved bend is provided in the string above the tool such that the tool is oriented for drilling into the formation laterally from the well. The drill string employed is flexible so that it can follow the curved path of the tool. The tool may comprise a drill bit, sonically driven by means of an orbiting mass oscillator coupled to the drill string or may comprise a hydraulic drilling tool in which hydraulic pulsating jets are generated in response to sonic energy developed in an orbiting mass oscillator and coupled to the tool through a resonantly driven drill string. In one embodiment a rotary table is provided to enable the rotation of the tool in one direction or the other or alternatively in opposite directions to obtain a variety of drilling patterns.

Abstract: Apparatus attachable to an ultrasonic drilling machine for drilling deep holes in very hard materials, such as boron carbide, is provided. The apparatus utilizes a hollow spindle attached to the output horn of the ultrasonic drilling machine. The spindle has a hollow drill bit attached at the opposite end. A housing surrounds the spindle, forming a cavity for holding slurry. In operation, slurry is provided into the housing, and into the spindle through inlets while the spindle is rotating and ultrasonically reciprocating. Slurry flows through the spindle and through the hollow drill bit to cleanse the cutting edge of the bit during a drilling operation.

Abstract: A close fitting piston of a material such as rubber is attached to the end of a rod string such as a sucker rod which is suspended inside a tubing string installed in an oil well. An orbiting mass oscillator is attached to the upper end of the rod string and is operated at a frequency such as to cause resonant standing wave vibration of the rod string. The piston member attached to the bottom end of the rod string is driven by the vibrational energy to in effect form an acoustical piston which is driven by the vibrational energy. This energy is coupled to the surrounding liquid and thence to the surrounding formation to effectively unclog the well and the casing string of contaminants which may be impeding the flow of effluent from the well. The piston means is made long enough so that it operates as an acoustic monopole with both ends of the piston being vibrationally in phase with the vibrational energy traveling in the surrounding liquid medium.

Abstract: A transducer assembly includes a piezoelectric transducer and a support member encasing the transducer. The transducer and the support member may have commonly disposed openings. The support member has a progressively increasing thickness at progressive positions from the opening to distribute equally the stresses at the different positions on the piezoelectric transducer. A plurality of such transducer assemblies may be disposed at spaced positions in an oil well with the support members supported on a support rail extending through the well. The support rail serves as an electrical ground. A bus bar extends through the well at positions corresponding substantially to the centers of the transducer assemblies. The bus bar is supported by electrically insulating spacer members extending from the support rail. A ring is supported at one end by the support rail and is coupled at the other end to a tubing. The tubing envelopes, the transducer assemblies, the support rail, the bus bar and the spacer members.

Abstract: An improved feedback system for use with an oscillator carried in a bore hole is provided. The feedback system connects the output legs of a well bore oscillator to the feedback nozzles of the oscillator. It consists of a detachable housing that contains two compliance chambers. Each chamber has a supply port and an exhaust port. Inertance passageways allow fluid to pass through each chamber.

Abstract: A ground boring tool known as a mole is fitted within its conical head (1) with a pneumatic-powered rotatory vibrator (8) which generates severe radial vibrations. As a result the progress of the mole through resistant ground is speeded or made possible. The mole also may be used for upgrading existing ducts with or without the destruction of an existing lining to such ducts. For destruction of existing linings elongate ridges (16) may be positioned on the surface of the cone.

Abstract: A drive shaft is rotatably mounted in a housing having a predetermined mass. This drive shaft has an eccentric portion at the output end thereof, this eccentric portion forming a crank arm. A drill bit is mounted on suitable bearings on the output end of the shaft adjacent to the eccentric crank arm portion. The drive shaft is rotatably driven causing the crank arm to generate sonic energy which is limited in amplitude by the crank throw reacting against the inductive inertia of the housing mass. The sonic energy thus generated causes the drill bit to orbit around at a sonic frequency to effect drilling action so as to produce a bore hole having a somewhat oversize diameter limited however in accordance with the housing's mass reactance and the throw of the crank arm.

Abstract: Sonic energy in a cycloidal or quadrature action pattern is generated in a drill stem by means of a sonic oscillator employing an eccentrically weighted rotor. The stem is coupled to the drill bit by means of a rocker-type joint thereby forming a pivot fulcrum for limited motion of the bit both vertically and laterally in a nutating path. The rocker action develops a powerful longitudinal vibratory force at the cutter teeth for more effective drilling action. The rocker joint in one embodiment is formed by horizontal and vertical shoulders formed in the top end of the bit assembly by virtue of an undercut portion formed in such assembly in which the lower edge of the drilling jacket is received with the bottom edge of such jacket opposite the horizontal shoulder and the inner surfaces of the jacket opposite the vertical shoulder. In another embodiment, suitable for use where precise control of drilling direction is required, limited rocking motion is provided by means of a special fulcrum guidance structure.

Abstract: The location of a section of drill pipe which has become stuck in a well some distance from the surface is first determined. The drill string above this location is unfastened from the drill string and removed from the well. A mechanical oscillator is connected to the bottom of the re-installed drill string through a sonic isolator section of drill pipe designed to minimize transfer of sonic energy to the sections of drill string above the oscillator. The oscillator is connected to the down hole stuck drill pipe section for transferring sonic energy thereto. A mud turbine is connected to the oscillator, this turbine being rotatably driven by a mud stream fed from the surface. The turbine rotates the oscillator to generate sonic energy typically in a torsional or quadrature mode of oscillation, this sonic energy being transferred to the stuck section of drill pipe to effect its freeing from the walls of the well.

Abstract: Journal bearings are employed to rotatably support the roller cones of a drill bit for drilling wells or the like. Enough clearance is provided at the journal bearing between the bearing pin and the roller cone to accommodate a thick film of fluid lubricant. The bearing is sonically driven, preferably by means of a resonant vibration system, in a torsional vibration mode, the torsional energy being developed in an elastic column which receives such energy from an orbiting mass oscillator. The roller cone is also mechanically rotated by virtue of conventional rotary motion of the drilling string.

Abstract: A driving and extracting apparatus has a hammer frame within which a reaction mass is freely movable. The reaction mass is caused to reciprocate within the hammer frame by the selective application of drive pressure to opposite drive cylinders at a frequency corresponding to the natural frequency of the mass. A pneumatic spring at each end of the reaction mass prevents contact between the reaction mass and the ends of the hammer frame. Sensors in the hammer frame detect the position of the reaction mass and adjust the pneumatic springs accordingly.

Abstract: Vibrational isolation is provided from the sonic energy employed to drive a piling or the like into the ground for the suspension and support system for the equipment, and for the power drive source for driving the sonic oscillators employed. A separate isolation system is provided for the support structure and for the power drive, each of these separate systems being optimized for the particular situation at hand. Thus, in providing vibrational isolation for the suspension and support mechanism, heavy large springs may be employed, capable of handling high loads, and having a relatively low spring rate to attain the desired isolation. On the other hand, the isolation system for the power drive employs relatively soft springs which effectively isolate the power drive from the vibrational excursions of the oscillator so as to avoid undue stress on the power drive, which might result in misalignment thereof, and damage to components of the power drive.

Abstract: A downhole pressure fluctuating tool having an improved acoustical circuit using a fluid oscillator to generate out-of-phase pressure fluctuations in two output legs, one connected to an acoustical compliance inside the tool and the other connected to an acoustical compliance exterior of the tool in a cavity partially formed by the wall of the well. An acoustical inertance with a pressure node at its midregion connects the two acoustical compliances, and said midregion communicates with the annulus between the body of the tool and the wall of the well to discharge fluid from the body at the pressure node to minimize acoustical losses in the annulus.

Abstract: Method and apparatus for recovering a stuck element from deep in a well. The lower end of an elastic steel column is attached to the upper end of the stuck element. The upper end of the column extends above the top of the well and is attached to a reaction mass lying vertically thereabove through (1) an accelerometer and then (2) vertically mounted compression springs in parallel with a vertically mounted servo-controlled hydraulic cylinder-piston assembly. A substantially constant upward load is applied to the reaction mass, and the piston of the hydraulic assembly is reciprocated under servo control to apply vertical vibration to the upper end of the column. This vertical vibration is adjusted through the servo control to an appropriate resonant frequency for the column in the range of 1/2 Hz to 25 Hz, and the frequency is maintained at resonance by a feedback system relying on maintaining a phase difference of 90.degree.

Abstract: A well casing to be installed in the ground is resonantly driven at a sonic frequency by means of an orbiting mass oscillator. A wedging probe member is optionally attached to the end of the casing and is driven by the vibratory energy to facilitate the penetration of the earthen material ahead of the casing. A closure wall is fitted to the bottom of the casing, this closure wall having jet nozzles formed therein. While the casing member and probe member are being vibratorily driven by the sonic energy, pulsating jets of water are emitted through the jet nozzles to aid in the cutting of the earthen formation along with the sonic vibratory energy, the sonic energy markedly enhancing the hydraulic jet action by virtue of the pulsating force it imposes on the hydraulic jets.

Abstract: A sonic damper unit which is placed directly above a drill collar string to damp out unwanted complex wave vibrations of the string both longitudinal and lateral in vibration mode. The damper unit comprises a tubular section which is filled with small pieces of material trapped therein which may comprise pellets of metal, pebbles, ceramic, etc. A longitudinal channel may be formed within the tubular damper unit for transporting mud therethrough and to be mixed into the trapped pellets or the like. The damper unit is preferably located in a low impedance region of the standing wave pattern formed in the string some distance from the bit, e.g. the top of the drill collar string. The pellets are capable of motion in a random pattern and thus effectively respond to the frequency content of complex vibrational wave modes both lateral and longitudinal and effectively damp out any such unwanted vibrational energy which may appear in the drill collar string.

Abstract: A hammer for driving piles comprises an anvil adapted to rest on top of a pile to be driven and a weight arranged to travel through a stroke between an upper position and a lower position. At least one flexible member interconnects the anvil and weight in such a way that when the weight travels to its lower position the flexible member is in tension and prevents the weight striking the anvil. The tension in the flexible member transfers the energy of the weight in a progressive fashion to the anvil.

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: Harmonic resonation of cutting elements against the earth formation is impeded in a rotary drag-type drill bit by providing connection means which yieldably and resiliently support the cutting elements from the drill bit but which deflects or vibrates with different natural resonant harmonic frequencies. The different natural harmonic frequencies tend to cancel or nullify resonance of any one of the connection means. The connection means can also be externally damped against vibrational movement.

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 deep vibrator includes a propulsion head (1) vibrating in a transverse direction with respect to the longitudinal axis of a suspension tube propulsion head being secured to the lower end of a suspension tube (2) while the outer wall of the suspension tube (2) includes pipes (4) arranged in the longitudinal direction thereof having at the lower end of the propulsion head (1) a spraying nozzle through which water may be fed under pressure, further spraying nozzles being distributed along the length of the pipes (4,5) and so aligned that they spray water into the annular space surrounding the suspension tube (2) thereby washing ground material toward the propulsion head.

Abstract: A deviated borehole is drilled with a rotary drilling technique in which the drill string is vibrated at a suitable frequency and amplitude to reduce the friction of the drill string against the lower side of the borehole and to promote the free movement of the drill string therein.

Abstract: A portable, electrohydraulic, acoustic transmitter releasably attaches to a solid medium such as a drill string to generate essentially longitudinal, acoustic signals in the medium. The signals are frequency modulated so that encoded messages may be transmitted between a surface and subsurface location to activate downhole equipment.

Abstract: A drill bit is connected to the bottom end of a longitudinally elastic drill stem which is contained within a jacket. An orbiting mass oscillator is coupled to the drill stem, this oscillator generating vibrational energy at a sonic frequency. The rotation axis of the oscillator is parallel to the drill stem, the drill stem being driven elastically, preferably at a frequency such as to set up standing waves therein, whereby circumferentially successive lengthwise oriented regions around the periphery of the column cyclically elongate and contract longitudinally in rotary progression. This longidudinal vibratory energy is transferred to the drill bit causing nutation thereof such that successive portions of the bit drive into the work material in a progression of longitudinal impulses as the stem undergoes circumferentially successive longitudinal cyclic motion in response to the vibratory energy applied thereto.

Abstract: A roller cone drill bit which is supported for rotation on a bearing pin by means of a journal bearing is sonically driven, preferably by means of a resonant vibration system formed in an elastic column which receives vibratory energy from an orbiting mass oscillator. The roller cone also is mechanically rotated by virtue of conventional rotary motion of the drilling string. Enough clearance is provided at the journal bearing between the bearing pin and the roller cone to provide a thick film of lubricating oil at this bearing.

Abstract: Vibratory drill apparatus is disclosed which is adapted for automatic self-balancing to compensate for variations in hardness of the material being drilled and/or dulling of the cutting blades which occurs during the drilling operation. The apparatus includes a tubular casing adapted to be connected to a rotating shaft and a drill assembly comprising a plurality of coaxially extending pipe members, each being located one within the other, the upper region of the drill assembly being received within the lower region of the casing. A drill head is defined at the lower region of the drill assembly. The pipe members are interconnected such that they are mutually fixed to each other for simultaneous rotation about their axis and such that each pipe member is free to move in the axial direction relative to the other pipe members.

Abstract: A column of elastic material such as steel is lowered into an oil well by means of a derrick to a position such that the end portion thereof is within a liner to be removed. The end portion of the column has clamping means thereon which are employed to tightly clamp the column to the liner. High level and variable resonant sonic energy is then applied to the column from the surface and transmitted along the column to the liner. The sonic energy operates to loosen the liner from the surrounding earthen material which usually has an adhesive tarry substance which tightly holds the liner. Vertical bias force, which may be varied from time to time to apply variable bias both upwardly and downwardly, as well as torsional bias in some instances are employed to aid in loosening the liner, the sonic energy operating to hysteresis heat the tarry adhesive until it softens and the liner can be removed by drawing the column upwardly with the derrick.

Abstract: The invention discloses a method and apparatus for placing, insitu, beneath roadways and the like, pipe or other longitudinal members, without the need to remove the overburden. This accomplished by vibrating the pipe into position with the use of a special frame which holds the pipe and a vibrating tool and guides the pipe into its insitu position.

Abstract: Means are provided to rotatably drive a cutter blade device about a central point so as to bore a circular hole in the ground. Elastic bar means is vibrationally excited at a sonic frequency by means of an orbital mechanical oscillator, the frequency of the oscillator being adjusted to provide resonant standing wave vibration of the bar means. Vibrational energy is transferred from the bar means to the cutter device in unidirectional (rectified) pulses, the vibrational energy aiding the rotary torque action of the cutter device and causing the earthen material to be broken into small size cuttings. The vibrational energy is applied to the cutter device at a location thereon away from the rotational axis of the cutter device, therefore maximizing the availability of the sonic energy in the cutting action and providing a substantial lever arm at the central portions of the device.

Abstract: Process and apparatus for the ultrasonic treatment of underground rocky strata, primarily for drilling therein, and for increasing the permeability of the strata. A flushing medium is made to flow through a mechanical drilling tool such as a rotary drill bit with rock-breaking elements, a pressure wave is superposed on the static pressure of the flowing medium at the location of rock breaking, and the frequency of the pressure wave in the ultrasonic range, preferably between 20 and 100 kHz; good results have been obtained at 27 kHz. The inventive apparatus includes a passageway in the tool for the flushing medium, a resonance chamber in the path of the medium, together with an exciting or interference element, constituting means for changing the flow conditions of at least part of the medium from laminar to turbulent, producing therein a pressure wave, and superposing the latter, as aforesaid. The resonance chamber preferably opens into a jet nozzle forming part of the drilling tool.

Abstract: A system for the transmission of data along a borehole during drilling operations which includes an acoustic transmitter receiver and mechanical filters. Data is acoustically propagated from the transmitter to the receiver along a portion of the drill string which is isolated from noise generating elements of the drilling system by means of the mechanical filters.

Abstract: A hydraulically actuated driving tool is provided with a ground engageable member which is driven into the ground by the action and reaction of a drive mass which is free to slide within the tool and which is repetitively forced away from and back to the ground engageable member in a manner determined by a hydraulic control system. Each repeated cycle of operation engenders two separate forces to drive the ground engageable member into the ground, one being the force exerted by high pressure fluid in the hydraulic control system when the drive mass is forced away from the ground engageable member and the other being the force exerted when the drive mass impacts back upon the ground engageable member. A switch means is provided whereby the returning drive mass initiates the next cycle of operation of the hydraulic control system.

Abstract: Torsional sonic energy is generated by means of a sonic generator and coupled to an elastic member to cause torsional resonant vibration thereof. The output of the torsional resonant member is coupled through an acoustic rectifier device to a drilling bit to simultaneously provide both torsional and vertical drive components to the bit to effect a spiral "screw" type driving action thereof. The rectifier action results in unidirectional high level pulses of the resonant sonic energy to the bit, causing the bit to be driven both rotatably and downwardly in a pulsating manner.

Abstract: An electric hammer comprising a housing accommodating a stator, a hammer piston reciprocably mounted in the stator, and a shock absorber including a resilient member and an intermediate member disposed between the hammer piston and the resilient member, the mass of the intermediate member being greater than that of the hammer piston.

Abstract: A drill housing is pivotally connected to the forward end portion of a boom member that swings upwardly from a frame of a mobile drilling machine. A hydraulic motor is secured to the gear housing and provides rotary power from a drive shaft through a pair of meshing gears to a drill chuck that is arranged to receive a drill bit or a roof bolt. A percussion weight is concentrically positioned within the drill housing and is axially aligned with the drill bit for imparting percussive forces to the drill bit. The percussion control is maintained through a servovalve that is supported on the drill housing and is controlled remotely by an electronic control module. The servovalve controls the flow of pressurized fluid from a source through ports in the drill housing connected to the servovalve by conduits to actuate a piston member for oscillation within the drill housing. Oscillation of the piston imparts a percussive force upon the percussion weight which is transmitted to the drill bit.

Abstract: An improved impact-type tool driven by pneumatic or similar power means is provided with a hand grip assembly which is substantially insulated from impact and shaking movements of the drive portion of the tool when the latter is in operation. Both the hand grip assembly and a supplementary weighted ring are disposed coaxially around the tool drive housing and are individually mounted for axial movement with respect thereto. The hand grip assembly is divided into upper and lower chambers by means of an intermediate annular guide member. A first spring disposed in the upper chamber interconnects the hand grip assembly with a flange on the upper portion of the tool drive housing, while a second spring disposed in the lower housing interconnects the hand grip assembly with the weighted ring. The characteristic frequency of the subsystem including the second spring and the weighted ring is chosen to be equal to the normal impact frequency of the tool when the latter is in operation.

Abstract: In a preferred embodiment of the invention, a dental scaler for the cleaning of teeth in which the scraper is an air-driven vibrator having a scraper mounted on a distal end of a rigid tubular device, with the rigid tubular device being mounted within a resilient support permissive of vibrations of the rigid tubular device and the vibrations of the tubular device being brought about by the exiting of air onto an air-cushioned rotary wheel mounted around the tubular device rotatably, the rotation thereof resulting from the force of the air from preferably a plurality of ports permitting the air to exit from the ports against the inner surface of the air rotary wheel, and the rotation of the rotary wheel bringing about the vibrations which are imparted to the rigid shaft, while the firmly supported tubular shaft within the resilient support structure thereof itself amplifies the magnitude of the vibrations by itself vibrating and transmitting its vibrations back to the rotary wheel, the outlet ports from the tu