Abstract:
A vibrational head for vibrational drilling utilising a tunable hydraulic supply to each end of a shuttle in a housing from which the vibrational output is taken. Valving is by a rotary valve system into and out of the chamber. The system with a drive in/drive out capability enables easy restart and effective operation.

Description:
[0001]     This is a continuation-in-part of PCT/NZ2004/000128 and PCT/NZ2005/000047 filed 18 Jun. 2004 and 17 Mar. 2005, respectively, and published in English. 
     
    
     TECHNICAL FIELD  
       [0002]     The present invention relates to vibrational apparatus.  
         [0003]     The present invention relates to vibration generation (which may or may not generate sound) as might be useful, inter alia, in vibrational drilling. The invention relates to related apparatus, methods, systems and procedures.  
         [0004]     The present invention relates to vibrational apparatus capable of providing a vibrational output for any one of a diverse range of purposes (e.g whether for the purpose of vibrating a drill string, a hopper, a powder feed line, a conveyor, or the like).  
       BACKGROUND  
       [0005]     There is frequently a need to provide vibration.  
         [0006]     Examples of use of vibration includes separation procedures reliant on the buoyancy of particulate materials in amongst other particulate materials, stripping of sand from a cast item, ground or other compaction, pile driving and drilling (including directional and/or rotary drilling).  
         [0007]     Usually vibration is generated reliant upon the spinning of an eccentric weight or counter rotating weights. See for example, U.S. Pat. No. 3,866,480 which discloses an orbital vibrator. Such orbiting mass oscillators may employ orbiting rollers which are rotatably driven around the inner race wall of a housing, as disclosed in U.S. Pat. No. 4,815,328 to Bodine, or an unbalanced rotor, the output of which is coupled to a drill bit as disclosed in U.S. Pat. No. 4,261,425 to Bodine.  
         [0008]     Other methods of creating and utilising sonic energy for application to a mandrel are also disclosed in U.S. Pat. No. 3,375,884 (Bodine), U.S. Pat. No. 3,379,263 (Bodine), U.S. Pat. No. 4,836,299 (Bodine), U.S. Pat. No. 4,527,637 (Bodine); U.S. Pat. No. 5,549,170 (Barrow) and U.S. Pat. No. 5,562,169 (Barrow) and WO01/83933 (Bar-Cohen).  
         [0009]     Japanese Patent Specification 57-179407 of Kawasaki Heavy Ind Ltd discloses a pile hammer employing a fluid actuator to operate in accordance to the resonance of the pile for the inherent frequency of the soil by providing a relief valve and a bypass circuit. Amplitudes of movement beyond those purely attributable to the liquid volumes are stated as being obtainable.  
         [0010]     Another device that uses hydraulic fluid to create vibratory impact is shown in Australian Patent 479534 (A/S Moelven Brug) (see U.S. Pat. No. 3,747,694).  
         [0011]     A preferred use of interest to ourselves for vibrational apparatus, but not one to which the vibrational apparatus needs be restricted, is in support of down hole drilling or boring equipment. Other uses include those hereinafter discussed.  
         [0012]     A variety of different prior art procedures have been disclosed including our own patent specifications reliant upon down hole directional drilling apparatus capable of being controlled through the drill string. It is advanced and/or rotated from the prime mover above ground or in an excavated region of the ground.  
         [0013]     In some applications however there is a preference to subject the drill string and the drill head to rapid vibrations thereby allowing the movement through the ground by breaking up encountered rock structures and/or compacting the surrounds thereby reducing the materials to be removed from down hole. Such procedures, whether reliant on resonance within the drill string or not, are referred to as vibrational drilling or boring.  
         [0014]     Sonic drilling methods and apparatus are disclosed, inter alia, in U.S. Pat. Nos. 4,836,299, 4,548,281 and 5,417,290 which are herein incorporated by reference.  
         [0015]     Sonic drilling is accomplished by vibrating a drill string to produce compressive and expansive waves in the drill string. The vibrations are induced in a longitudinal direction of the drill string and the drill string is preferably vibrated at a resonant frequency. The resonant frequency is dependent upon a number of factors including the length of the drill string.  
         [0016]     The vibrational forces on the drill string causes the drill string to contract and expand in the longitudinal direction. The vibrational forces at the bottom of the drill string shear, displace and/or otherwise fracture apart the soil and/or rock particles thereby cutting through the formation.  
         [0017]     It has also been disclosed in the art that drilling systems which employ cycloidal sonic energy as a method of drilling cause a highly effective action on the bottom and particularly the adjacent side walls of the bottom portion of a well bore by virtue of the cycloidal drilling action.  
         [0018]     The present invention recognises an advantage is derivable in the area of vibrational drilling where it is possible to commence the generation of the vibrational head whilst in its operative connection (directly or indirectly) with the drill string. For many prior art forms of sonic or other vibrational head re-starts are difficult owing to the need to retract the drill string from against a rock face and other structure that might be binding the drill string as a whole.  
         [0019]     Thus many vibrational apparatus rely upon the rotation of an eccentric. Others rely on pneumatics and/or hydraulics in order to reciprocate a piston which provides a direct output of the vibrational output. Such structures however, whilst disclosed for many end uses, have a downside in that where the device to which the output piston is attached has itself stalled there is a difficulty in ensuring a recommencement of the vibrational output as a consequence of the piston itself refusing to move relative to its cylinder or the equivalent.  
         [0020]     The present invention recognises a significant advantage to be derived from the vibrational commencement point of view and/or tuning point of view irrespective of how the apparatus is mounted. This arises from the fact that we have determined that a shuttle without a direct output to the apparatus to be vibrated can itself be sufficient without impacting solid to solid (whether in conjunction with hydraulic and/or pneumatics or not) to provide the requisite output from the containment structure of a shuttle i.e one end complement of a shuttle or both such end complements of the shuttle. It is to this in one aspect therefore that the present invention is directed to at least provide the public with the useful choice.  
         [0021]     It is an alternative or another therefore an object of one or some embodiments of the present invention to provide a vibrational head assembly and/or a vibrational head for such assembly which will provide the option of start-up without a need for retraction in such circumstances and/or separation of the vibrational head in the drill string.  
         [0022]     It is an alternative or another object of one or some aspects of the present invention to provide a vibrational head assembly and/or vibrational head for such an assembly which enables the generation of vibrations (optionally including sonic vibrations) into a structure without a requirement for tuning to a resonant frequency of the structure for it to be vibrative. In some aspects of the present invention is envisaged that start-up can commence without striving for resonance and/or without a need for resonance being achieved notwithstanding in some embodiments of the present invention such resonance can still be achievable by adjustment of control parameters as the vibrational head assembly is being used.  
         [0023]     In one or some other embodiments of the present invention, it is an object to provide a vibrational head and/or a vibrational head assembly not reliant upon the rotation of eccentrics but which imparts a useful vibration output that can be used in many situations or which at least provides the public with a useful choice (sonic vibrations alone generally do not develop enough energy to efficiently drill rock).  
         [0024]     It is an alternative or another object of one or some other embodiments of the present invention to provide constructions of a fluid driven vibration head for a vibration head assembly which confers some measure of isolation of key components from the affect of excessive vibration and/or by omission of a component or components avoids difficulty from any such vibration.  
         [0025]     It is an alternative or another object of one or more embodiments of the present invention to provide a vibration head and/or related vibration head assembly reliant upon separate fluid feeds, one for imparting the vibration and at least one for controlling, other input parameters e.g. amplitude, frequency, the valving, etc.  
         [0026]     It is an alternative or another object of one or more other embodiments of the present invention to provide a vibration head and/or vibration head assembly which has a fluid retrieval system that takes the fluid to ambient or near ambient pressures.  
         [0027]     It is an alternative or another object of one or more other embodiments of the present invention to provide vibration head support arrangements and/or buffers and/or linkages which provide some freedom(s) of movement between at least part of the vibration head and a supporting frame yet allows some relativity of movement therebetween.  
         [0028]     The present invention is also directed to vibrational apparatus with a drive in and a drive out capability (owing to a driven shuttle from which vibrational output is not directly taken) and to the related methods of operation and use which will at least provide a useful choice.  
       BRIEF DESCRIPTION OF THE INVENTION  
       [0029]     The present invention is adapted to provide a significant jackhammer effect which allows the device to rapidly penetrate rock formations.  
         [0030]     The present invention is directed to vibrational apparatus able to provide a drive in and drive out in use for a connected drill string owing to reliance on a shuttle not directly outputting to the drill string.  
         [0031]     The present invention in another aspect consists in vibrational apparatus capable of providing a vibrational output, said apparatus comprising or including  
         [0032]     a shuttle having first and second ends,  
         [0033]     a first complementary structure associating with the first end of said shuttle, and  
         [0034]     a second complementary structure associating with the second end of said shuttle,  
         [0035]     wherein there is a drive or drives to drive the shuttle alternately in each shuttling direction so that, in one direction, the first end moves away from the second complementary structure and, in the other driven shuttle direction, the second end moves away from the first complementary structure,  
         [0036]     and wherein the output of the vibration is from one or other, or both, of said complementary structures and not directly from the shuttle itself.  
         [0037]     Preferably said first and second complementary structures are fixed relative to each other insofar as distance is concerned.  
         [0038]     Preferably the drive(s) of the shuttle in at least one direction, and preferably both directions, is selected from any of the forms hereinafter discussed whether it is by virtue of a direct mechanical drive through pivot links, a magnetic drive, a hydraulic drive, a pneumatic drive, a combustive drive or any alternative or combination thereof.  
         [0039]     Preferably the drive type for the shuttle in each of its directions is the same but, in some less preferred forms of the present invention, a hybrid arrangement can be used.  
         [0040]     Preferably the shuttling is without solid to solid high impact or impact contact.  
         [0041]     Preferably said shuttle co-acts at least at one end with its complementary structure so as to provide a cushioning affect, e.g. by squeezing a fluid. Alternatively that can be at both ends. One or both ends of the shuttle (despite any guiding contact it may already have) can be adapted to contact part of the complementary structure only at the end of its shuttling travel or to contact some material interposed between that end of the shuttle and the complementary structure.  
         [0042]     Preferably the vibrational output is from one of the complementary structures.  
         [0043]     Preferably there is reliance upon the provision of an externally pressurised fluid as the sole means of empowerment of shuttle movement by being introduced so as to pressurise without further event between a complementary structure and said shuttle.  
         [0044]     In another aspect the present invention consists in apparatus for generating a vibrational (e.g. non sonic or sonic) output, said apparatus comprising or including  
         [0045]     a shuttle,  
         [0046]     a first complementary member to coact with the shuttle to define a first pressurisable chamber,  
         [0047]     a second complementary member to coact with the shuttle to define a second pressurisable chamber,  
         [0048]     a first valving arrangement to control fluid flow into and out of the first pressurisable chamber,  
         [0049]     a second valving arrangement to control fluid flow into and out of the second pressurisable chamber,  
         [0050]     one or more supply (supplies) of pressurisable fluid, or adaption(s) therefor, to the shuttle whereby each of the first and second valving arrangements can allow or not allow fluid entry to the respective chamber,  
         [0051]     one or more outtake (outtakes) of fluid, or adaption(s) therefor, whereby each of the first and second valving arrangements can allow or disallow fluid egress from the respective chamber;  
         [0052]     wherein the valving arrangements and shuttle movement relative to the complementary member(s) is such that as the first valving arrangement allows fluid entry to the first chamber thereby to expand both the first chamber and volume of fluid therein, the second valving arrangement allows fluid egress from the second chamber thereby to allow both compression of both the second chamber and the volume of fluid therein, and so forth in an alternating shuttle moving manner,  
         [0053]     and wherein the output is (directly or indirectly) from one or other (or both) complementary member(s) rather than the shuttle.  
         [0054]     Optionally the timing provided by the valving arrangements can allow some overlap of supply or exhaust flows between the respective chambers.  
         [0055]     The “shuttle” in some embodiments may be perceived as substantially static yet moving relative to the other componentry. The opposite may also be the case as are many hybrids of the two.  
         [0056]     Accordingly “shuttle” as used herein throughout should be understood as shuttling relative to other aspects of the assembly.  
         [0057]     In another aspect the present invention consists in apparatus for generating a vibrational output, said apparatus comprising or including  
         [0058]     a shuttle,  
         [0059]     a first complementary member to coact with the shuttle to define a first pressurisable chamber,  
         [0060]     a second complementary member to coact with the shuttle to define a second pressurisable chamber,  
         [0061]     a first valving arrangement to control fluid flow into and out of the first pressurisable chamber,  
         [0062]     a second valving arrangement to control fluid flow into and out of the second pressurisable chamber,  
         [0063]     one or more supply (supplies) of pressurisable fluid, or adaption(s) therefor, to the shuttle whereby each of the first and second valving arrangements can allow or not allow fluid entry to the respective chamber,  
         [0064]     one or more outtake (outtakes) of fluid, or adaption(s) therefor, whereby each of the first and second valving arrangements can allow or disallow fluid egress from the respective chamber;  
         [0065]     wherein the valving arrangements and shuttle movement relative to the complementary member(s) is such that as the first valving arrangement allows fluid entry to the first chamber thereby to expand both the first chamber and volume of fluid therein, the second valving arrangement allows fluid egress from the second chamber thereby to allow both compression of both the second chamber and the volume of fluid therein, and so forth in an alternating shuttle moving manner,  
         [0066]     and wherein one, some or all of the following features are present: 
        (a) the first and second complementary members and shuttle relate to each other on the same axis,     (b) the output is (directly or indirectly) from one or other (or both) complementary member(s) rather than the shuttle,     (c) the vibrational head when used for vibrational drilling (or some equivalent) has the shuttle independent of the drill string or equivalent means to be vibrated),     (d) there is no drill rod nor rod extension through the shuttle or vibrational head (thereby to enable, if desired, multiple vibrational heads to be used in delivering power to a drill string or other means to be subjected to vibration),     (e) the first and second complementary members are pistons or include pistons,     (f) the first and second complementary members may include pistons provided with circumferential or peripheral grooves but may or may not carrying piston rings and/or seals,     (g) the valving arrangement in each instance involves a rotary valve member having ports to open or close a fixed port or fixed ports to the chamber,     (h) each (or a common) valving arrangement includes a rotary valve member which includes an axial passageway to allow fluid outtake or supply (preferably outtake),     (i) each valving arrangement includes a rotary valving member, such rotary valving members being operated on a common rotational axis and out of phase one with the other,     (j) each valving arrangement is driven independently of the fluid supply and fluid outtake,     (k) it is possible to regulate amplitude of movement of the shuttle independently of the frequency of shuttling by having a control of the valving arrangement that is independent of the pressure and/or volume of supply to and/or outtake of fluid from the valving arrangement,     (l) the valving arrangement is proximate to the chamber thereby to optimise to a minimal distance between valving by the valving arrangement and the action of fluid being introduced into the proximate chamber, (i.e. to enable a shorter time for the shock wave of the input fluid to energise the piston and/or piston (preferably to enable operation at higher frequency when desired, to enable resonance at shorter stroke or amplitude, to provide higher efficiency and/or provide greater flexibility and versatility)),     (m) the outtake of fluid from a chamber is not used to power the movement of the shuttle,     (n) the outtakes of fluid is (are) to substantially ambient pressures prior to, if desired, such fluid being made available (e.g. by pumping) for a return to the vibrational head,     (o) the fluid is primarily a liquid but may include some entrained gas (e.g. air) so as to confer some cushioning effect in the chamber,     (p) the shuttle can be caused to move even if there is no movement of one or other or both of said first and second complementary means e.g. as is the case if attached to a bound drill string,     (q) the vibrational head irrespective of whether or not its operation is tuned to provide resonance in a body or device (such as a drill string) directly or indirectly attached to one or other, or both, of the complementary means, can be operated with a jack hammer effect,     (r) the fluid supply and/or outtake involves or is preferably to involve an accumulator,     (s) the vibrational head is supported by a frame relative to which the vibrational head has at least in part some degree(s) of freedom to move,     (t) the vibrational head is linked to a frame by articulating (e.g. dog bones) or other linkages to allow some movement of a complementary means relative to the frame,     (u) the vibrational head is supported by a frame and is buffered so as not to pass unnecessary shock into the frame (preferably such buffering including, in conjunction with any optional suitable linkage or linkages, the use of cushioning gas bags or the equivalent) (preferably as air bags as opposed to air springs are utilised),     (v) the vibrational head is supported from a frame capable of being manipulated directly or indirectly to control the disposition of the vibrational head,     (w) the vibrational head is optionally carried or supported directly or indirectly by a frame which directly or indirectly [e.g. a carried carriage or slide, or support(s) for the frame as a carriage or slide] (but not linked to the vibrational head by any rigid member) has mounted at least part of an endless drive assembly for the valving arrangement(s) and/or a fluid motor for use in driving the valving arrangement(s),     (x) a carriage or slide, or support(s) for a frame as a carriage or slide, carries a hydraulic motor and/or drive component (e.g. to be via a flexible drive) for rotating a drill string and/or a mandrel therefor, the vibrational head being locatable but with some freedom(s) to move by said frame,     (y) drives and/or motors are to be or are, at least to some extent, substantially isolated from the vibration(s) of the vibrational head, (e.g. standoff mounts being provided therefor, belt drives, etc.).        
 
         [0092]     Reference hereinafter to energising the “piston” includes alternatively and/or as well the energising of the reactive structure of the piston. Likewise reference to “piston grooves” refers also and/or instead to grooves of the piston surrounding structure (irrespective of whether carrying rings and/or seals).  
         [0093]     Preferably the apparatus is substantially as hereinafter described but versions (less desired) may have substituted for the second complementary member (or second piston) some other arrangement to provide a driven return of the shuttle in use.  
         [0094]     In another aspect the invention consists in a vibrational head assembly suitable for generating an output (e.g. suitable for direct or indirect vibrational input into a structure (e.g. a drill string), or other medium capable of transmitting/absorbing the vibrational input, said assembly having  
         [0095]     a frame, and  
         [0096]     a vibrational head carrying, carried by, substantially locating and/or substantially being located by the frame,  
         [0097]     wherein the vibrational head has at least some freedom(s) to move relative to the frame, and/or vice versa,  
         [0098]     and wherein the vibrational head has a shuttle and two components each component with the shuttle defining one of two variable volume chambers, the shuttle being moveable relative to each component under the action of a fluid under pressure being supplied into one variable volume chamber and being released from the other variable volume chamber, and vice versa,  
         [0099]     and wherein the vibrational output is not or is not to be directly or indirectly from the frame nor the shuttle,  
         [0100]     and wherein it is adapted so that if driving a drill string with the vibrational output each cycle provides a drive in and a drive out of the drill bit carried by the drill string.  
         [0101]     This benefits, inter alia, straight line drilling in fractured formations, back reaming and/or drill string life.  
         [0102]     In another aspect the invention consists in a vibrational head assembly for generating an output (e.g. for direct or indirect vibrational input into a drill string), said assembly having  
         [0103]     a frame,  
         [0104]     a vibrational head carrying, carried by, substantially locating or substantially being located by the frame,  
         [0105]     wherein the vibrational head has a spaced pair of parts or components (“complementary members” whether unitary or otherwise) each associating with a shuttle,  
         [0106]     and wherein the shuttle has a valving arrangement whereby a variable volume chamber can be defined by each complementary member with the shuttle as a consequence of shuttle position relative to each complementary member, such that when one chamber is at its allowed maximum volume the other is at its allowed minimum volume, and vice versa,  
         [0107]     and wherein the shuttle is caused to move from rest with respect to said complementary members thereafter to shuttle by fluid applied into a first chamber whilst being released from the second, by fluid applied into the second chamber whilst being released from first, and so forth,  
         [0108]     and wherein 
        (a) the first and second complementary members and shuttle relate to each other on the same axis,     (b) the output is (directly or indirectly) from one or other (or both) complementary member(s) rather than the shuttle,     (c) the vibrational head when used for vibrational drilling (or some equivalent) has the shuttle independent of the drill string or equivalent means to be vibrated,     (d) there is no drill rod nor rod extension through the shuttle or vibrational head (thereby to enable, if desired, multiple vibrational heads to be used in delivering power to a drill string or other means to be subjected to vibration),     (e) the first and second complementary members are pistons or include pistons,     (f) the first and second complementary members may include pistons provided with circumferential or peripheral grooves but may or may not carrying piston rings and/or seals, [and/or vice versa e.g. cylinder has the grooves],     (g) the valving arrangement in each instance involves a rotary valve member having ports to open or close a fixed port or fixed ports to the chamber,     (h) each (or a common) valving arrangement includes a rotary valve member which includes an axial passageway to allow fluid outtake or supply (preferably outtake),     (i) each valving arrangement includes a rotary valving member, such rotary valving members being operated on a common rotational axis and out of phase one with the other,     (j) each valving arrangement is driven independently of the fluid supply and fluid outtake,     (k) it is possible to regulate amplitude of movement of the shuttle independently of the frequency of shuttling by having a control of the valving arrangement that is independent of the pressure and/or volume of supply to and/or outtake of fluid from the valving arrangement,     (l) the valving arrangement is proximate to the chamber thereby to optimise to a minimal distance between valving by the valving arrangement and the action of fluid being introduced into the proximate chamber, (i.e. to enable a shorter time for the shock wave of the input fluid to energise the piston (preferably to enable operation at higher frequency when desired, to enable resonance at shorter stroke or amplitude, to provide higher efficiency and/or provide greater flexibility and versatility)),     (m) the outtake of fluid from a chamber is not used to power the movement of the shuttle,     (n) the outtakes of fluid is (are) to substantially ambient pressures prior to, if desired, such fluid being made available (e.g. by pumping) for a return to the vibrational head,     (o) the fluid is primarily a liquid but may include some entrained gas (e.g. air) so as to confer some cushioning effect in the chamber,     (p) the shuttle can be caused to move even if there is no movement of one or other or both of said first and second complementary means e.g. as is the case if attached to a bound drill string,     (q) the vibrational head irrespective of whether or not its operation is tuned to provide resonance in a body or device (such as a drill string) directly or indirectly attached to one or other, or both, of the complementary means, can be operated with a jack hammer effect,     (r) the fluid supply and/or outtake involves or is preferably to involve an accumulator,     (s) the vibrational head is supported by a frame relative to which the vibrational head has at least in part some degree(s) of freedom to move,     (t) the vibrational head is linked to a frame by articulating (e.g. dog bones) or other linkages to allow some movement of a complementary means relative to the frame,     (u) the vibrational head is supported by a frame and is buffered so as not to pass unnecessary shock into the frame (preferably such buffering including, in conjunction with any optional suitable linkage or linkages, the use of cushioning gas bags or the equivalent) (preferably as air bags as opposed to air springs are utilised),     (v) the vibrational head is supported from a frame capable of being manipulated directly or indirectly to control the disposition of the vibrational head,     (w) the vibrational head is optionally carried directly or indirectly by a frame which directly or indirectly [e.g. a carried carriage or slide, or support(s) for the frame as a carriage or slide] (but not linked to the vibrational head by any rigid member) has mounted at least part of an endless drive assembly for the valving arrangement(s) and/or a fluid motor for use in driving the valving arrangement(s),     (x) a carriage or slide, or support(s) for a frame as a carriage or slide, carries a hydraulic motor and/or drive component (e.g. to be via a flexible drive) for rotating a drill string and/or a mandrel therefor, the vibrational head being locatable but with some freedom(s) to move by said frame,     (y) drives and/or motors are to be or are, at least to some extent, substantially isolated from the vibration(s) of the vibrational head, standoff mounts being provided therefore.        
 
         [0134]     Preferably the apparatus is substantially as hereinafter described but versions (less desired) may have substituted for the second complementary member (or second piston) some other arrangement to provide a driven return of the shuttle in use.  
         [0135]     In another aspect the invention consists in a vibrational head assembly for generating an output (e.g. for direct or indirect vibrational input into a drill string), said assembly having  
         [0136]     a frame,  
         [0137]     as a vibrational head carrying, carried by and/or substantially locating the frame,  
         [0138]     wherein the vibrational head has (preferably at least within bounds) at least some freedom(s) to move relative to the frame, and/or vice versa,  
         [0139]     and wherein at least some of the mass (“the shuttle”) of the vibrational head (inclusive of at least some of said fluid) under the action of valves and a pressurised fluid supply or pressurised fluid supplies for opposing variable volume chambers defined in part in each case by the shuttle, in use, is able to shuttle with respect to two other masses of the vibration head each of which defines in part a said chamber,  
         [0140]     and wherein it is from at least one of these other masses from which there is to be the vibrational output.  
         [0141]     In another aspect the invention consists in a vibrational head for generating an output (e.g. for direct or indirect vibrational input into a drill string),  
         [0142]     and wherein the vibrational head has at least one piston in a complementary cylinder moveable relative to each other to define a variable volume chamber under the action of a fluid under pressure supplied into or released from the variable volume chamber,  
         [0143]     and wherein one, some or all of the following features are present: 
        the vibrational head when used for vibrational drilling (or some equivalent) has the shuttle independent of the drill string or equivalent means to be vibrated),     there is no drill rod nor rod extension through the shuttle or vibrational head (thereby to enable, if desired, multiple vibrational heads to be used in delivering power to a drill string or other means to be subjected to vibration),     the outtake of fluid from a chamber is not used to power the movement of the shuttle,     the outtakes of fluid is (are) to substantially ambient pressures prior to, if desired, such fluid being made available (e.g. by pumping) for a return to the vibrational head,     the fluid is primarily a liquid but may include some entrained gas (e.g. air) so as to confer some cushioning effect in the chamber,     the vibrational head irrespective of whether or not its operation is tuned to provide resonance in a body or device (such as a drill string) directly or indirectly attached to one or other, or both, of the complementary means,     can be operated with a jack hammer effect,     the fluid supply and/or outtake involves or is to involve an accumulator,     the vibrational head is supported by a frame relative to which the vibrational head has at least in part some degree(s) of freedom to move,     the vibrational head is linked to a frame by articulating (e.g. dog bones) or other linkages to allow some movement of a complementary means relative to the frame,     the vibrational head is supported by a frame and is buffered so as not to pass unnecessary shock into the frame (preferably such buffering including, in conjunction with any optional suitable linkage or linkages, the use of cushioning gas bags or the equivalent) (preferably as air bags as opposed to air springs are utilised),     the vibrational head is supported from a frame capable of being manipulated directly or indirectly to control the disposition of the vibrational head,     the vibrational head is carried directly or indirectly by a frame which directly or indirectly [e.g. a carried carriage or slide, or support(s) for the frame as a carriage or slide] (but not linked to the vibrational head by any rigid member) has mounted at least part of an endless drive assembly for the valving arrangement(s) and/or a fluid motor for use in driving the valving arrangement(s),     a carriage or slide, or support(s) for a frame as a carriage or slide, carries a hydraulic motor and/or drive component (e.g. to be via a flexible drive) for rotating a drill string and/or a mandrel therefor, the vibrational head being locatable but with some freedom(s) to move by said frame,     drives and/or motors are to be or are, at least to some extent, substantially isolated from the vibration(s) of the vibrational head, standoff mounts being provided therefore.        
 
         [0159]     The present invention also consists in a vibrational head of or suitable for a vibrational head assembly of any of aforementioned kinds i.e. without a said frame. Whilst preferably the apparatus has a frame to hold the complementary members in association with the shuttle, that frame need not be a carriage on another frame e.g. the frame can be crane suspended.  
         [0160]     In still a further aspect the present invention consists in the use of a vibrational head or a vibrational head assembly of the present invention for the purpose of providing a vibrational input into a body, media or device.  
         [0161]     In yet a further aspect the present invention consists in a method of drilling which involves the operative use of a vibrational head or vibrational head assembly in accordance with the present invention.  
         [0162]     In yet a further aspect the present invention consists in, in combination, a drill string and a vibrational head assembly (or components therefor) and (optionally) related linkages, hydraulic supplies etc.  
         [0163]     Optionally a single rotary valving unit (preferably with a rotational axis substantially perpendicular to a shuttle stroke axis) can be provided.  
         [0164]     Such an embodiment is (as in  FIG. 10  hereof) is more prone to bogging down and restart difficulties. It is less preferred as shuttling can be hard to achieve at low input pressures.  
         [0165]     Preferably such a rotary valve member has a single radiused array of openings, such openings allowing the opening of an inlet port and the regions of the valving member between such openings closing the inlet ports.  
         [0166]     Preferably the effect for each inlet port is to “open”, “close” and “open” the inlet port with sequential openings whilst the out of phase other inlet port is respectively “closed”, “opened” and “closed” by the respective diametrically opposed closing regions of the valve member and the opening sandwiched thereby. However overlap can be allowed to some extent.  
         [0167]     In another aspect the present invention consists in vibrational apparatus comprising or including  
         [0168]     a piston,  
         [0169]     a chamber assembly defining a chamber in which the piston is adapted to shuttle between stroke limits, said chamber having a chamber end region at and/or beyond each stroke limit of the piston, there being an inlet port into and an outlet port out of each chamber end region,  
         [0170]     a fluid supply assembly associated with said chamber assembly capable of supplying a pressurised fluid or any pressurised fluid it may receive in use to the inlet ports of the chamber,  
         [0171]     a fluid collection assembly associated with said chamber assembly to collect fluid from the outlet ports (and preferably capable of supplying that collected fluid for reuse via a said source of pressurised fluid),  
         [0172]     a first rotary valve capable of an out of phase allowing or disallowing of fluid movement from the fluid supply assembly into each said inlet port by opening or closing same,  
         [0173]     a second rotary valve capable of an out of phase disallowing or allowing of fluid movement from the chamber out of each said outlet port by closing or opening same,  
         [0174]     a first drive to rotate the first rotary valve,  
         [0175]     a second drive to rotate the second rotary valve, and  
         [0176]     a timing link between the first and second drives such that, for each chamber end region, an inlet port will generally be open when its associated outlet port is closed, and vice versa, and such that, each state of the opening and closing of each end chamber end region is generally out of phase with the condition of the other,  
         [0177]     wherein in use, there is or will be a vibrational output via the first assembly, the second assembly and/or an output member of or carried by the piston as a consequence of rapid piston shuttling within the chamber.  
         [0178]     The term “drive” includes a dedicated or undedicated drive and can amount to no more than some transmission element or assembly capable of being driven (e.g. by a hydraulic or electric motor) [directly or indirectly] thereby to rotate the rotary valve(s).  
         [0179]     The “timing link” can be and preferably is a driving link such that the drive into one drive in turn drives the other.  
         [0180]     Preferably preferments are as previously stated.  
         [0181]     Preferably the timing link between the drives is a belt or chain linking pulleys, sprockets, or the like.  
         [0182]     Preferably the vibrational apparatus is adapted to be linked into a remote hydraulic circuit to supply said pressurised fluid.  
         [0183]     Preferably the vibrational apparatus is capable of being “tuned” so as to provide desired amplitudes of movement and/or resonance outputs reliant upon a control of the pressure and/or volume of the pressurised fluid being supplied and/or a control of the timing link and drives.  
         [0184]     Preferably the stroke axis is rectilinear.  
         [0185]     Preferably the piston has two journaled extensions (not necessarily required to rotate but capable of sliding in the bearing or other surround).  
         [0186]     Preferably one extension being the output member.  
         [0187]     Preferably the inlet ports are laterally of the chamber with respect to the stroke axis.  
         [0188]     Preferably the outlet ports are laterally of the chamber with respect to the stroke axis.  
         [0189]     Preferably the piston (irrespective of whichever aspect of the present invention is involved) carries an output member.  
         [0190]     In some forms of the present invention the output member can be an extension of the piston or piston assembly such that the piston proper is rectilinearly guided but there is at least one protruding end of that assembly to provide the output.  
         [0191]     In some forms of the present invention such protruding end(s) and/or indeed the piston itself can act as a conduit for a quite separate fluid supply, e.g. it may be desirable to duct a gas, liquid or other material down and/or up from the drill string with which the output member might be associated in use, such fluids being kept distinct from the operating fluid of the vibrational apparatus.  
         [0192]     In yet a further aspect the present invention consists in a method of vibrating a structure, assembly or member which involves associating vibrational apparatus of the present invention therewith and operating that vibrational apparatus so as to induce vibration thereof.  
         [0193]     In yet a further aspect the present invention consists in pile driving, boring and/or drilling involving the use of vibrational apparatus in accordance with the present invention.  
         [0194]     The present invention also consists in pile driving and/or drilling or boring assemblies of any suitable kind which includes vibrational apparatus of the present invention, e.g. can include a drill head, a drill string and a vehicle or other prime mover to supply a hydraulic fluid as the working fluid.  
         [0195]     As used herein “shuttle” and “piston” have the broadest meanings envisaged herein with respect to what moves and what does not, etc.  
         [0196]     As used herein the term “and/or” means “and” or “or”, or, where the context allows, both.  
         [0197]     As used herein the term “comprises” or “comprising” can mean “includes” or “including”.  
         [0198]     As used herein the term “(s)” following a noun can mean both the singular and plural versions of that noun.  
         [0199]     As used herein the term “stroke limit of the piston” can refer to limits of a rectilinear stroke or any curved stroke (e.g. can include a stroke of a piston that swings about a pivot axis or other support, whether fixed or moving).  
         [0200]     Reference herein to “out of phase” in respect of the allowing or disallowing of fluid movement from the fluid supply assembly(s) means substantially registering an opening of the rotary valve(s) to allow entrance of fluid into one end region whilst the other end region has its inlet port substantially closed by the or a rotary valve(s).  
         [0201]     Reference herein to “out of phase” with respect to the inlet and outlet ports of the same chamber end region refers preferably, but not necessarily so, to the inlet port being closed by the or a rotary valve(s) whilst the outlet port is open.  
         [0202]     The term “out of phase”, in any of its defined forms, is inclusive of both no overlap (i.e. no partial opening with partial closing) and some overlap.  
         [0203]     As used herein the term “rapid” with respect to piston shuttling within the chamber refers to any speed of operation of the shuttle that will provide an output vibration of use to the application at hand and, in the case of “sonic drilling or boring”, includes at least several cycles per second. By way of example, and without limitation, the cycles/sec are preferably above 20 cycles/sec. Many hundreds of cycles/second are envisaged, e.g. up to, for example, one or several thousand cycles/second. Vibrational apparatus of the present invention operating with, for example, a hydraulic liquid as the fluid, at for example, about 200 bar (as is common for hydraulic fluid of excavators) can operate the shuttle at about 200 cycles/second.  
         [0204]     Preferably the rapid cycling envisaged is from 20 to 500 cycles/second.  
         [0205]     As used herein “fluid” includes a liquid (such as a hydraulic liquid—usually an oil but not necessarily so), a gas (for example, nitrogen or air) and, or mixtures of liquids and air or liquids and particulate solids or gas and particulate solids or any other suitable combination, e.g. emulsions of different liquids, mixtures of gases, etc.  
         [0206]     The term “head” or “headed” in respect of any cylinder or chamber envisages a chamber closed by the stationary and/or movable “piston” irrespective of whether or not valving is via any one or more of a head, the cylinder and the piston. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0207]     A preferred form of the present invention will now be described with reference to the accompanying drawings in which  
         [0208]      FIG. 1  is a three dimensional cutaway (the top complementary member or piston not being shown) of a preferred vibration head in accordance with the present invention having rotary valve members as part of the valving and timing arrangement for each chamber and having them aligned axially,  
         [0209]      FIG. 2  is a top view of the apparatus of  FIG. 1  showing at the centre line the device cutaway by the quarter sector as shown in  FIG. 1 ,  
         [0210]      FIG. 3  is a front view of the apparatus of  FIG. 2  shown in elevation,  
         [0211]      FIG. 4  is the end view AA of the apparatus of  FIG. 3 ,  
         [0212]      FIG. 5  is a section of the vibrational head shown in FIGS.  1  to  4 , such section being along the centre line yet showing the device in elevation,  
         [0213]      FIG. 6  shows a frame and ancillary apparatus assembly in accordance with the invention, there being shown an outtake mandrel for connection into the body to be vibrated by the first complementary means or directly from the first complementary means (e.g. for powering by way of example a drill string).  
         [0214]      FIG. 7  is for an opposed piston variant (i.e. having complementary variable volume chambers) a timeline against shuttle movement under the two scenarios (A)  FIG. 8 ′,  FIG. 9 ′, and so forth cycling and (A)  FIG. 8 ,  FIG. 8A ,  FIG. 9 ,  FIG. 9A ,  FIG. 8 ,  FIG. 8A ,  FIG. 9, 9A ,  FIG. 8 , and so forth cycling,  
         [0215]      FIG. 8 ′ is a flow diagram of the apparatus shuttling to the right,  
         [0216]      FIG. 9 ′ is a flow diagram of the apparatus shuttling to the left,  
         [0217]      FIG. 8  is a flow diagram as in  FIG. 8 ′,  
         [0218]      FIG. 8A  is a flow diagram where oil feed pressures momentarily match and reliance is placed on an accumulator in the oil system (not shown), but where the shuttle movement is a momentary precursor to the condition of  FIG. 9 ,  
         [0219]      FIG. 9  is a flow diagram as in  FIG. 9 ′, and  
         [0220]      FIG. 9A  is a flow diagram as in  FIG. 8A  also where reliance is placed on an accumulator (the same or different—preferably different) but where the shuttle movement is a momentary precursor to the condition of  FIG. 8 .  
         [0221]      FIG. 10  is an exploded cut away drawing of a less preferred embodiment, this embodiment having a single rotary valve adapted to control the opening and closure of inlet ports but having an always open outlet port structure but of lesser opening than the inlet ports when open,  
         [0222]      FIG. 11  is a form of the present invention having two rotary valves, one for the inlet port set and one for the outlet port set thereby not requiring any differential in size of the inlet and outlet ports,  
         [0223]      FIG. 12  shows another broken away view of the embodiment of  FIG. 11 ,  
         [0224]      FIG. 13  shows how in one other embodiment but relying on the mechanism typified by  FIG. 11 , there can be a sprocket or other drive of each rotary valve timed relative to each other by a timing belt or belts and/or an idle shaft such that input by, for example, an electric or hydraulic motor as shown has the capability of controlling the speed of rotation of both rotary valves and  
         [0225]      FIG. 14  is a diagrammatic view of preferred apparatus in accordance with the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0226]     In the preferred form of the present invention there are two variable volume chambers and each operates in an out of phase manner with respect to the other such that there is a positive powering of each chamber to a larger volume under the valve controlled pressure and volume of supplied fluid thereby avoiding the need for outtakes of the fluids to provide any direct drive to diminish the volume of that same chamber otherwise than from an expanding effect on the other variable volume chamber. Preferably in use neither chamber is ever to be devoid of liquid/fluid therein.  
         [0227]     In the arrangement as shown in  FIG. 1 ,  
         [0228]      1  denotes a piston assembly,  
         [0229]      2  denotes a stationary valve block assy,  
         [0230]      3  denotes an O-Ring  
         [0231]      4  denotes a cap screw  
         [0232]      5  denotes a bearing block  
         [0233]      6  denotes a cap screw  
         [0234]      7  denotes a cap screw  
         [0235]      8  denotes a top center block  
         [0236]      9  denotes a bottom center block,  
         [0237]      10  denotes a nut,  
         [0238]      11  denotes a washer  
         [0239]      12  denotes a valve shaft  
         [0240]      13  denotes a spherical roller thrust bearing  
         [0241]      14  denotes a single lip seal  
         [0242]      15  denotes a synchronous drive pulley  
         [0243]      16  denotes a taper lock bush  
         [0244]      17  denotes an O-ring  
         [0245]      18  denotes an O-ring  
         [0246]      19  denotes a valve shaft bush housing assy  
         [0247]      20  denotes a stationary valve block spacer  
         [0248]      21  denotes a cap screw  
         [0249]      22  denotes a valve shaft bush assy  
         [0250]      23  denotes a cap screw  
         [0251]      24  denotes a piston seal rim  
         [0252]      25  denotes a bearing block seal rim  
         [0253]      26  denotes a tire  
         [0254]      27  denotes a bearing cage  
         [0255]      28  denotes an O-ring, and  
         [0256]      29  denotes a plastic piston spacer.  
         [0257]     With reference to the arrangement as shown in  FIG. 5  it can be seen that there is a first variable volume chamber  30  and a second variable volume chamber  31  and whilst a tire like flexible connection  32  and  33  respectively links each piston including part  34  and  35  with the shuttle  36 , the amplitude of movement envisaged is relatively small during most operations. Preferably they range from a fraction of a millimetre to several centimetres but could be more the larger the vibrational head is. The frequency can be from a few Hertz to thousands.  
         [0258]     Each chamber is bounded by the piston part of its component  34  or  35  which preferably each includes peripheral pressure drop grooves with and/or without piston rings and/or seals. As can be seen each stationary valve block  37  or  38  is ported and coacts with a rotating valve member or rotating valve shaft  39  and  40  respectively to either allow fluid into or fluid from its proximate variable volume chamber  30  or  31 .  
         [0259]     Axially within each rotating valve member  39  is a passageway which ports radially therefrom which is used preferably for the outtake of fluid back to a collection chamber form whence it can be returned (e.g. by pumping) as shown in  FIG. 5 . The oil inlet lines are shown supply via passageways to the valving arrangement exteriorly of the rotating valving member  39  or  40 .  
         [0260]     A separate fluid supply (not shown in  FIG. 5 ) is utilised for a hydraulic motor  41  which is to operate via the member  42  and endless drive belt or the equivalent  43  for each of rotating valve members  39  and  40 . Such a hydraulic motor receives a fluid supply preferably provided separately from the volume of fluid being supplied for the purpose of energising the sonic head insofar as the shuttle movement is concerned.  
         [0261]     As can be seen, preferably the arrangement which includes  41 ,  42  and  43 , is on a slide  44  relative to a frame  45  which directly or indirectly supports the vibration head. The frame  45  itself can be arranged as a slidable carriage on a support rail or other structure  46  such that preferably it operates relative thereto within limits.  
         [0262]     If desired the slide  44  and the rail or other structure  46  can be linked.  
         [0263]     Alternatively the frame  45  can be suspended from, for example, a crane.  
         [0264]     Shown in  FIG. 6  is the vibrational head having a drill string mandrel or the equivalent  47  adapted to be rotated by an endless drive belt/chain or the equivalent  48  driven by a hydraulic motor  49  (separate hydraulic feed again). Optional rotation of the mandrel  47  will rotate or manoeuvre a drill string attached thereto whilst the mandrel or the equivalent  47  is vibratable (directly or indirectly) under the action of the proximate piston or complementary means of the vibrational head.  
         [0265]     Such a proximate piston, piston assembly, or complementary means is preferably supported so as to be moveable at least in a longitudinal sense to some extent relative to the frame  45  and for this purpose some guided linkages are preferably provided. For example, links  50  and  51  on either side of the vibrational head can link by a pivot  52  or  53  to the vibrational head and by  54  and  55  to the frame  45 . At the same time limits of movement can be imposed by compression springs  56  and  57  (or air bags) in conjunction preferably with airbags  58  and  59  which provide a cushioning or damping effect between the vibrational head and the frame  45  and in turn the carriages or supports  44  and  46 .  
         [0266]     It can be seen therefore that the linkages allow some semblance of rotation of the dog bone links whilst at the same time allowing some axial displacement of the vibrational head as a whole, yet the shuttle  36  is free of direct contact with the frame and/or the slides or carriages  44  and  46  otherwise than as a consequence of the flexible drives and the hose and/or other linkages not shown in the attached drawings.  
         [0267]     Preferably all connections (including of hydraulics) are of flexible vibration resistance hoses connected so as to avoid involuntary disconnection.  
         [0268]     The vibrational head of the present invention can start with a jackhammer effect even without drill string tuned for resonance. Control thereafter can be (a) speed of rotating valves (rotor) and/or (b) volume of fluid (e.g. oil). This can alter frequency yet still allow power to be added independent of drill string length. The drill string can have torque and pressure placed on it without affecting the shuttling vibrational head shuttle. This affords huge drilling control.  
         [0269]     The independent systems for rotor control from that of the shuttle oil supply, the vibrational isolation of the vibrational head save primarily for vibrational shock, the frame within a frame arrangements, and the short distance of oil shock travel bestow significant advantages.  
         [0270]     Operation of cycles as in FIGS.  7  to  9 A will now be described with apparatus having the flow capabilities previously described. Please appreciate where such a device as shown in FIGS.  1  to  9 A is, say, about 1.5 m (it can be any size) long the shuttle movement is of the order of, say, 0.1 mm to 15 mm (the amplitude), the parameters of operation affecting applitude. Preferred forms can be of any scale and the foregoing is representative only. Larger shuttle sizes require larger heads.  
         [0271]     The operation can be a direct millisecond range movement as in scenario (A) referred to in respect of  FIG. 7  (i.e.  FIG. 8 ′,  FIG. 9 ′, etc) but can instead be scenario (B) where conditions as in  FIGS. 8A and 9A  each requires an accumulator in the oil circuit to allow the momentary movement required to the following  FIG. 9  and  FIG. 8  instantaneous condition respectively.  
         [0272]     It is envisaged that apparatus in accordance with forms of the present invention as shown in FIGS.  10  to  13  will preferably be driven by a hydraulic system from, for example, by a vehicle or a standing prime mover to which the apparatus can be linked. Preferably also there can be a diversion in the inflow to the apparatus of such pressurised hydraulic fluid through such closure and/or choke valves etc. as may be required separately to provide a hydraulic drive to the or one of the rotary valves (and thus by the timing or synchronising link in turn to the other) as well as separately the charging of the fluid alternately to each chamber end region.  
         [0273]     Hydraulic systems typically run at from 3000 to 5000 psi whereas this invention will typically run at below 3000 psi and more preferably in the range under 2000 psi.  
         [0274]     Preferably the pressure hoses and/or returns [most preferably the pressure input hoses] are to some extent isolated from the shuttle in order to reduce heat build up.  
         [0275]     In the embodiment shown in  FIG. 10 , less preferred as it may require resonance for effectiveness, the piston  60  has extensions  61  journaled so as to allow axial movement. It matters not if the piston and the journals are circular in cross section and/or whether or not they are allowed to rotate within the chamber defined by the chamber assembly  62 .  
         [0276]     As can be seen in the embodiment of  FIG. 10  there is a first chamber end region  63  and a second chamber end region  64  each accessible to an inlet port  65  and  66  respectively.  
         [0277]     Positioned so as to rotate substantially about an axis normal to the stroke axis of the piston  60  is a rotary valve  66  having on a same radius areas of no opening  67  and openings  68 .  
         [0278]     As can be seen one of these openings  68  (designated  68 A) is opening the pressurised liquid supply chamber  69  of the fluid supply assembly into communication with the chamber end region  63  whilst there is no such access via the second inlet port  66  into the chamber end region  64  owing to the out of phase state, i.e.; there is a region  67  holding the second inlet port  66  closed whilst the first inlet port  65  is open. The vice versa situation onwards will allow alternate charging to each chamber end region.  
         [0279]     As shown in  FIG. 10  there is a first exhaust or outlet port  70  for the chamber end region  63  and a second outlet port  71  for the chamber end region  64 . In a situation as shown in  FIG. 10  where these ports are always kept open preferably means (in this case a plate having openings  72  and  73 ) other than a second rotary valve ensures that the inflow of liquid via an opening  68  and a port  65  or  66  will always be at a greater rate than there is any exhausting out via the corresponding opening  72  or  73  as part of a hydraulic return circuit.  
         [0280]     Persons skilled in the art will appreciate how the fluid supply assembly  74  can be supplied with an infeed of a hydraulic fluid into the chamber  69  with the fluid finding its own way from there into one or other of the chamber end regions  63  and  64  and from thence via the exit ports ( 70  and  72  in one instance and  71  and  73 ) in the other instance back to the pumping system of, for example, the vehicle or prime mover with which the apparatus might be linked for return of that same hydraulic liquid back to the chamber  69  or such diversion thereof, as might be considered desirable, to a hydraulic motor for driving the rotary valve  66 .  
         [0281]     Another form of the present invention is that shown in  FIG. 12 . This has similar to  FIG. 10 a  piston  75  and journaled extensions  76  and  77  thereby defining chamber end regions  78  and  79  controllable by, for example, the rotary valve  80  with its openings and non openings similarly arrayed to the manner shown by reference to the embodiment of  FIG. 10 . The assembly  81  with its chamber  82  is adapted to receive pressurised hydraulic liquid and to selectively allow its movement into first one and then the other of the chamber end regions  79  and  79 .  
         [0282]     Timed to the rotation of the rotary valve  80  is a rotary valve member  83  which has the role of allowing the exhausting of hydraulic liquid from first one and then the other of the chambers  78  and  79  in an out of phase relationship to that of injection thereby to reciprocate the piston. The exhaust rotary valve  83  preferably rotates at the same speed as the rotary valve  80  and the spacings of its openings is appropriate for each outlet from the chambers  78  and  79 .  
         [0283]      FIG. 11  best shows the arrangement of these openings with a port  84  being closed by not being aligned with an opening  85  of the input rotary valve  80  whilst an outlet port  85  of that same chamber end region  86  is aligned with an opening  87  to allow outflow into the chamber  88  of the fluid collection assembly  79  from whence it is ducted back via, for example, the excavator, for pumped recycled use.  
         [0284]     The arrangement of  FIG. 13  shows in a bench test form an electric motor  90  (ideally it would be a hydraulic motor in use) driving directly a drive assembly adapted to rotate a first rotary valve (not shown) whilst a link belt  91  through an idle shaft  92  in turn through a second link belt  93  drives the other rotary valve (not shown) thereby providing the appropriate vibrational movement (caused by reciprocation of the piston) that extends into the journaled output member  94 .  
         [0285]     In operation therefore appropriate tuning can occur of the vibrations required. If we assume that an vehicle or prime mover has a capability of providing a substantially constant hydraulic flow and pressure into the apparatus of the present invention and there is a division of the flow so that one flow can supply a hydraulic motor to achieve rotary valve rotation whilst the other flow is to charge selectively either side of the piston under the action of the rotary valve timed or synchronised movement, a very simple control regime applies. This is far less complicated with far fewer moving parts and requiring lower tolerances than for any of the prior art procedures previously disclosed.  
         [0286]     For example, if the inlet port at one end is shut by its rotary valve then the hydraulic liquid cannot go anywhere and nothing will happen by way of charging into that end region. Contrarily however the same will not be the case at the other end if that is in part or wholly open.  
         [0287]     Accordingly when an input rotary valve is turned (spun) the hydraulic oil flows into the piston chamber end region and forces the piston to the end of its stroke. The rotary valve continues to turn and through its timing or synchronism with the other rotary valve, the “spent” hydraulic oil is allowed to release to exhaust. At the same time or subsequently (or both) the first rotary valve diverts oil to the other end of the piston in turn forcing the piston back.  
         [0288]     The hydraulic drive through timing belts means that if the rotary valves in unison rotate slowly (say 10 rpm) the piston will shuttle very slowly but if both rotary valves are rotated at say 1000 rpm the piston could be moving, say, at approximately 200 times per second. Thus tuning for the various ground conditions can be achieved by the simple expediency of manipulating the speed of the synchronised rotary valves by the control of the fluid input to the hydraulic motor.  
         [0289]     By way of an example the preferred form of the present invention with reference to a drill string vibrating apparatus adapted to attach to a drill string A.  
         [0290]     The apparatus howsoever mounted (preferably compliantly suspended) (not shown) has end members C and D that act as a first complementary means and F and H which act as a second complementary means. These complementary means are held in a fixed relationship by the members G. The shuttle E moves back and forward within the physical bounds provided and ideally has a lesser shuttling distance to avoid impacting.  
         [0291]     It matters not whether or not the shuttle itself acts as a piston within a bore of a complementary end or vice versa. Nor does it matter if there is no piston in cylinder relationship at all. It is the shuttling that is important howsoever caused.  
         [0292]     With reference to  FIG. 14  the following is depicted.  
         [0293]     (A) Drill string  
         [0294]     (B) Rotary joint/drive pulley  
         [0295]     (C) End plate  
         [0296]     (D) Adjacent member  
         [0297]     (E) Shuttle  
         [0298]     (F) Adjacent member  
         [0299]     (G) Tie rods  
         [0300]     (H) End plate  
         [0301]     The purpose of the shuttle (E) is to transfer energy onto the adjacent members (D) and (F) in a reciprocal motion. This transfer of energy can be achieved by the injection of oil between the shuttle and its adjacent members with the appropriate timing to cause the shuttle to move in a reciprocal motion, thus to cause the drill string to move in a linear motion in parallel with the shuttle motion thus transferring the energy down the drill string to the bit in the most efficient manner.  
         [0302]     The shuttle mass is the key to the transfer of the energy to the adjacent members. The change in direction of travel imparts the energy to the adjacent members. The more mass the shuttle has the greater the energy required to achieve this change in direction and is directly linked to the horse power required and therefore the more energy that can be imparted to the drill bit. The relationship between the mass of the shuttle and the total mass of the drill string being vibrated has to be considered and sized appropriately.  
         [0303]     The shuttle action has the advantage of never being in a situation of being stalled by locking or binding of the drill string in the drill hole. The shuttle can deliver full power to the drill string or attachments that may be fitted.  
         [0304]     The end plates and tie rods (G) (H) are the link between the adjacent members and these transfer the reciprocating energy to the drill string.  
         [0305]     The shuttle action could be powered in different ways. 
        (1) The ends of the shuttle could have a piston like arrangement fitted to operate like a conventional engine with air and fuel being fed through the adjacent members with valves fitted and firing alternately to reciprocate in the same way as being fed by oil.     (2) The shuttle could be moved by magnetic means. For example, ends of the shuttle could have electromagnets or rare earth magnets fitted in such an arrangement that when the shuttle (E) was rotated it would pulse of the adjacent members that were also fitted with magnets fitted in such a way that would cause the shuttle to reciprocate.     (3) A mechanical cam could be fitted to the shuttle (E). This cam could be held by bearings off the adjacent members (D) and (F). Driven by preferably hydraulic motors this action would impart the energy to the adjacent members in the same way.        
 
         [0309]     Hybrids of the foregoing and/or other drives can be used.  
         [0310]     The examples above all have a common theme. 
        (1) The shuttle preferably never needs to touch the adjacent members in a physical sense as this would cause a spike shock wave to be generated. This would damage the drill string joints and associated down hole equipment.     (2) The movement of the shuttle is never dependent on the drill string or attached equipment, being free to move in relation to the movement of the shuttle.     (3) The shuttle action drives the drill string in both directions i.e in and out and in doing so allows drill bit rotation to move with very little drag on the drill bit carbides. This action is unique to this shuttle driven drill—also allows for back reaming of holes. 
 
 Other Considerations: 
       
 
         [0314]     No other drill action involving a drifter powers the drill string out of the hole while drilling the hole “IN”. They rely on the bounce of the drill string.  
         [0315]     A drifter hits steel on steel and in doing so causes a destructive shock wave through the drill string.  
         [0316]     N.B A drifter is the name given to a conventional hydraulic rock drill.