Top head drive and mast assembly for drill rigs

A top head rotary drive and mast assembly for drilling which is adapted to be readily mounted on a derrick of a conventional truck, crawler or other vehicle so as to be movable from a stored position adjacent the derrick to a deployed position spaced from the derrick for drilling. The mast is adapted to be pivotally connected by at least one upper support arm to the derrick of the vehicle. The deployment and retraction of the mast and the top head rotary drive relative to the derrick are accomplished utilizing either a control device for moving a holding plate which is movable along the mast and to which the top head rotary drive is mounted or by separate lifting device. The invention is also directed to a combination top head drive and mast assembly and drilling rig and method for their use.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 This invention is generally directed to drilling rigs used for creating
 wells or blast holes and more particularly to a top head drive and mast
 assembly which is adapted to be mounted to a conventional mast or derrick
 of a drill rig such that the drill rig can operate with a rotary top head
 drive. In a preferred embodiment, the invention will be described as being
 mounted to a conventional cable drilling rig wherein the top head rotary
 drive may be easily moved into position for rotary drilling and stabilized
 in position for advancing a drill string. The top head rotary drive and
 mast assembly can easily be raised and moved into close proximity with an
 existing mast or derrick, such as a derrick of cable drill rig, such that
 the top head rotary drive and mast are out of alignment with a drill hole
 thus allowing conventional drilling equipment to be fully operational.
 2. Brief Discussion of the Related Art
 In the boring or drilling of wells or blast holes and the placing of well
 casing or lining, generally two types of drilling rigs are used. A first
 rig, known as a cable drill rig, operates using a bit and drill stem which
 is raised and lowered for impact by a cable system.
 As opposed to the reciprocal driving movement created by a cable rig, other
 rigs, known as rotary air rigs, provide rotation and compressed air
 through a drill string for drilling. Generally, such rotary air rigs are
 more efficient in generating greater drilling speeds for drilling wells in
 a more expeditious manner.
 Conventional rotary air rigs incorporate a drill table mounted along a base
 of a mast. The rotary table includes a drive motor. In order to drill
 utilizing a rotary table, a kelly system is required wherein a kelly rod
 is connected to each section of drill pipe as the drill string is lowered.
 Because of the requirement for the drive kelly to engage within a chuck of
 the rotary drive head, a significant amount of time and labor is required
 when adding or removing a pipe section to a drill string as the kelly must
 be removed from the uppermost drill pipe section during each step.
 To overcome the deficiencies of rotary table drive systems, newer top head
 rotary drive systems have been developed. Top head drive systems include a
 rotary drive head driven by one or more motors. The rotary drive heads are
 guided in a vertically reciprocating motion along rails of masts of such
 systems. Various types of assemblies may be utilized to raise and lower
 the top head rotary units during use. The benefit of the direct or top
 head rotary drive system is that the kelly bar required for drive tables
 is not necessary and the top head rotary drives may be connected directly,
 or through a coupling member, to an uppermost pipe section of a drill
 string.
 It is preferred that the top head air rotary drive be used when retrieving
 and or replacing sections of a drill string for purposes of replacing a
 drill bit, such as in a sequence of tripping out sections of a drill
 string to replace a drill bit and tripping in pipe sections to reform the
 drill string.
 In view of the foregoing, there remains a need to adapt vehicles having
 derricks, including conventional cable drilling rigs, such that they may
 operate with top head rotary drives which may be easily moved into a
 drilling position to facilitate the expeditious drilling of a bore or well
 hole and yet can be easily moved out of alignment position with the hole
 to permit the use of other equipment such as conventional cable equipment.
 Some examples of prior art top head rotary drive drill systems are
 disclosed in the U.S. Pat. No. 3,994,350 to Smith et al., U.S. Pat. No.
 4,421,179 to Boyadjieff, U.S. Pat. No. 4,589,503 to Johnson et al., U.S.
 Pat. No. 4,800,968 to Shaw et al., U.S. Pat. No. 5,038,871 to Dinsdale,
 U.S. Pat. No. 5,107,941 to Berry, U.S. Pat. No. 5,501,286 to Berry, and
 U.S. Pat. No. 5,794,723 to Caneer, Jr. et al.
 SUMMARY OF THE INVENTION
 A top head rotary drive and mast assembly for use with a vehicle or
 equipment having an elevatable mast or derrick such as a conventional
 cable drilling rig wherein the assembly includes a rotary air drive head
 which is mounted to a holding plate which is movable along a mast by being
 drivingly connected to a control device for raising and lowering the
 holding plate relative to the mast. In a preferred embodiment, the control
 device is a hydraulic piston which includes a rod having a rotary device,
 such as double pulley, mounted thereto about which extend cables or
 similar elements, one of which extends over an upper pulley at the crown
 of the mast downwardly to a point of connection with the holding plate and
 another which extends beneath a lower rotary device or pulley mounted on
 the mast such that a remote end connects to a portion of the holding
 plate. Ends of the elements which are remote from the holding plate are
 anchored relative to the mast such that, as the piston associated with the
 hydraulic cylinder is moved in or out, the elements are correspondingly
 played in or played out to maintain constant tension on the holding plate
 to thereby ensure that the holding plate is stabilized with respect to the
 mast.
 The rotary air drive head and mast assembly further includes at least one,
 and preferably two, support arms which extend outwardly from an upper
 portion thereof and which arms have free ends which are adapted to be
 pivotally connected to support the mast from a derrick of a conventional
 truck or crawler. To stabilize the mast when mounted to the derrick of
 such conventional equipment, the assembly further includes at least one,
 and preferably two, upwardly inclined stabilizer arms which are connected
 to a lower portion of the mast and extend upwardly at an angle of between
 approximately 30.degree. to 45.degree. to outer ends which are adapted to
 be secured to the frame of the conventional vehicle. In a preferred
 embodiment, a further stabilizer arm is provided which is connected at one
 end to the lower portion of the mast in vertically spaced relationship
 with respect to the inclined stabilizer arms and which includes an outer
 or free end which is adapted to be connected to the frame of the
 conventional vehicle, such as a conventional cable drill rig. This
 additional stabilizer arm is inclined at an angle which varies from the
 angle of inclination of the inclined stabilizer arms and preferably, the
 additional stabilizer arm is oriented generally perpendicular with respect
 to a point of attachment on the mast and frame of the rig.
 In one preferred embodiment, the top head air rotary drive and mast
 assembly includes at least one, and preferably two, restraint elements
 which are adapted to be connected at opposite sides of the holding plate
 and extend vertically upwardly therefrom to points of connection on the
 derrick of the conventional cable or other rig. In some embodiments, the
 restraint elements are cables having looped lower ends which are adapted
 to be mounted over hooks provided on the holding plate. The restraint
 elements create a re-direction of force from the control device which
 normally moves the holding plate in reciprocating motion along the mast.
 When the restraint elements are in place, should the control device be
 activated to move the holding plate toward the lower portion of the mast,
 the restraint elements will prevent such movement thereby causing the
 connections between the control device and the holding plate to supply a
 lifting force on the mast when the mast has been connected by the upper
 support arms to the derrick of the conventional drill rig and the
 stabilizing arms disconnected from the derrick of the conventional rig. As
 the mast elevates, it will pivot about the upper support arms and will be
 drawn into close proximity abutting the derrick. The mast is thereafter
 retained in the raised position by the control device. In the preferred
 embodiment, the control device is a hydraulic cylinder such that hydraulic
 pressure is utilized to retain the mast in an elevated position.
 In another embodiment, the lowering and raising of the top head air rotary
 drive and mast assembly to and from a deployed position relative to a
 conventional derrick is accomplished using a winch type device mounted to
 the mast or by a cable extending to a winch device mounted to the rig on
 which the derrick is supported.
 The top head air rotary drive and mast assembly further includes a guide
 table mounted to the lower portion of the mast having an opening therein
 through which the drill string extends. In a preferred embodiment, a
 section of the table may be pivoted away from a main portion of the table
 thereby allowing lateral access to the guide opening therethrough. A
 holding and break out wrench is further provided and pivotally supported
 adjacent the lower portion of the mast for use in supporting drill string
 pipe sections and for making and breaking connections between drill pipe
 sections and between the rotary drive head and a section of drill pipe.
 An appropriate anchor element is secured or mounted to the guide table for
 purposes of allowing a cable, such as a cable of a cable drill rig, to be
 secured thereto for facilitating lowering of the mast to a drilling
 position.
 It is the primary object of the present invention to provide a top head or
 direct air rotary drive and mast assembly which can be easily mounted to a
 derrick or mast of a conventional drill rig, truck, crawler or other
 vehicle, to thereby adapt such vehicle to be used for direct air drive
 rotary drilling.
 It is also an object of one embodiment of the present invention to provide
 a top head air rotary drive and mast assembly which includes a holding
 plate for the top head rotary unit which plate is guidely mounted to the
 mast and connected to a control device such that, when the assembly is
 mounted to a conventional derrick and restraint elements are secured
 between the holding plate and such derrick, the operation of the control
 device can be used to efficiently raise and lower, under its own weight,
 the mast relative to the derrick to thereby deploy the assembly to an
 aligned position to drill or bore a well hole or raise the assembly to a
 stored position adjacent the derrick to thereby permit the use of other
 equipment such as conventional cable equipment.
 It is yet a further object of the present invention to provide a top head
 air rotary drive and mast assembly for use with conventional drilling rigs
 wherein the assembly is stabilized to counter torque generated by the top
 head air rotary drive when drilling by the use of stabilizer arms which
 are selectively mounted to the lower portion of the mast of the assembly
 and the frames of the conventional drill rigs.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
 With continued reference to the drawings, the top head air rotary drive and
 mast assembly 20 of the present invention is shown mounted to a
 conventional cable drilling rig 22 having a derrick 23. The invention,
 however, may be used with other vehicles, including trucks and crawlers,
 having a mast or derrick mounted thereto.
 As illustrated in FIGS. 10-15, the drilling rig includes a frame 24 mounted
 to support wheels 25. To stabilize the rig for drilling, four hydraulic
 jacks 26 are provided each have an extensible foot for engaging a surface
 to thereby stabilize the vehicle and prevent rocking or tilting of the
 vehicle when the derrick 23 is raised and during drilling. The derrick may
 include a base section 28 which is pivotally mounted at 29 adjacent the
 rear of the rig and from which extends an extendable section 30 having a
 block or pulley assembly 32 mounted thereto over which an operating cable
 33 of the rig extends. The cable is connected to a hoist or winding drum
 (not shown) mounted on the chassis of the drill rig and reinforcing 34 is
 shown in dotted line in the drawings for supporting the derrick when
 raised.
 As clearly shown in FIG. 11, the derrick of the cable rig is inclined from
 the vertical at approximately 1 to 11/2 degrees such that the drill cable
 33 falls free of the rear of the derrick during use. With a derrick height
 of 36 to 38 feet, the bore hole for any drill string being supported by
 the derrick would be approximately 28 to 36 inches from the base of the
 derrick spaced rearwardly from the drill rig. In this regard, one of the
 benefits of the present invention is that it allows the top head rotary
 drive and mast assembly to be pivotally mounted to the derrick in such
 manner that the assembly may be used for drilling by being deployed
 outwardly relative to the base of the derrick and generally in line with
 the upper portion of the derrick so that any drill hole created by the
 assembly will be properly aligned with the drill cable 33 of the drill
 rig. In this manner, the drilling of the hole may be accomplished using
 the present invention and, thereafter, the assembly raised to a position
 in close proximity to the derrick, as is shown in FIG. 11, wherein the
 cables of the cable drill rig may be used for drilling or placing well
 casing. The addition of the assembly to a conventional cable rig greatly
 enhances the utility of the cable rig and also allows conventional use of
 the cable rig for those operations which are more suitably performed by
 the components of the cable rig.
 The top head rotary drive 40 includes one or more drive motors 43A and 43B,
 see FIGS. 5 and 16, which, in the preferred embodiment, are hydraulic
 motors which are connected by hydraulic lines 41 and 42, see FIGS. 11 and
 16, to a source of hydraulic pressure. The top head rotary drive 40 is
 carried by a holding plate 44 by being bolted or otherwise secured
 thereto. The top head rotary drive includes an output drive connection or
 coupler 45 which is designed to be engageable with a section "S" of drill
 pipe, as shown in FIG. 13.
 The holding plate 44 is mounted to a mast 45 having oppositely oriented
 generally C-shaped vertically extending columns 47 and 48 which define a
 pair of elongated guide flanges 49 and 50, respectively. The holding plate
 44 includes rearwardly extending generally L-shaped flanges 51 and 52, see
 FIG. 7, which are spaced so as to guidingly engage the holding plate 44 on
 opposite sides of the flanges 49 and 50 to thereby guide the holding plate
 in its vertical reciprocating motion along the length of the mast 45. The
 elongated C-shaped columns are reinforced by a plurality of cross bracing
 54.
 The mast 45 further includes a base 56 used for initially stabilizing the
 mast when being lowered to a position for drilling, as is illustrated in
 FIG. 13. Spaced above the base is a guide table 58 having a guide opening
 60. To facilitate the placement of some drilling tools on the end of the
 drill string, the guide table includes a section 62 that is pivotally
 mounted at 63 so as to pivot away from the opening 60, as is illustrated
 in dotted lines in FIG. 8. This allows unobstructed lateral access to the
 opening for the placement of tools or casing beneath the opening 60 in the
 guide table.
 To facilitate the connecting and breaking of joints or couplings between
 drill pipe sections, and as shown in FIG. 1, the present invention also
 includes a hydraulic wrench 66 having hydraulic lines 67 and 68 associated
 therewith and which includes an outer jaw 69. The wrench is pivotally
 mounted on an arm 70 so as to be movable into alignment with the opening
 60 in the guide table 58.
 The guide table 58 is further provided with a retaining loop 72 for
 purposes of allowing attachment of a hook 73, see FIGS. 11 and 12, for
 purposes of facilitating the lowering of the assembly of the present
 invention to a deployed position, utilizing the conventional cable 33 of
 the cable rig 22.
 The top head rotary drive and the mast assembly 20 further includes a
 control device 75 which is mounted to the mast 45 for controlling the
 reciprocal vertical movement of the holding plate 44 and thus the top head
 rotary drive 40 relative to the guide table 58. With reference to FIGS. 3
 and 4, in the preferred embodiment, the control device includes a
 hydraulic cylinder having a base connected at 76 to the mast and having an
 extension rod 77 reciprocally mounted therein and which is connected at a
 yolk 78 to a double pulley or similar rotary guide member 79. Hydraulic
 fluid is conveyed to and from the hydraulic cylinder by way of an inlet
 and an outlet 80 and 81. It should be noted that other types of control
 devices, such as winches or electrical motors and the like, may be used
 and be within the teachings of the present invention.
 The control device 75 is connected with the holding plate 44 by way of a
 first or upper cable or similar element 82. Other flexible and sturdy
 elements such as chains may be utilized to create the connection between
 the control device 75 and the holding plate 44. The element 82 is shown as
 having an outer end portion 84 secured to a connector 85 extending from an
 upper portion of the holding plate 44. From the outer end 84, the element
 extends over an upper rotary guide device or pulley 86 which is mounted at
 the crown 87 of the mast 45. From there, the element extends downwardly
 within the mast about the double pulley 79 and then upwardly to a guide
 pulley or rotary element 89 secured along the crown 87 of the mast and,
 thereafter, downwardly where the opposite end thereof is secured to an
 adjustable tensing device 94 which is secured to the mast.
 The control device 75 is also connected by way of a lower cable or similar
 element 90 which is the same as element 82. The lower element is secured
 at its outer end 91 to an attachment element 92 secured to the holding
 plate 44. From the holding plate, the lower element extends over a lower
 guide pulley 93 mounted adjacent a lower portion of the mast and then
 upwardly about the double pulley 79 and from there to an adjustable
 tensing and anchoring device 95 which is secured to the mast.
 From the foregoing description, it is noted that as the holding plate 44 is
 reciprocally moved by the control device 75, the cable or other elements
 82 and 90 will maintain an equal tension on the upper and lower portions
 of the plate at the points of connection 85 and 92 thus stabilizing the
 plate relative to its position on the mast 45. Appropriate adjustment may
 be made to each element at the adjustable tensing devices 94 and 95.
 The mast 45 further includes an upper bail element 98 which is secured to
 and extends upwardly from the crown 87 thereof and which is used for the
 initial mounting of the mast relative to a conventional derrick and
 thereafter for purposes of securing a safety line or chain, such as shown
 in FIG. 14 at 100, which extends to a bracket 101 formed on the derrick
 23.
 With specific reference to FIGS. 1-4, the mast of the present invention
 also includes a pair of spaced mounting brackets 105 and 106 each having a
 central opening therein, as illustrated in FIG. 3, for purposes of
 receiving a locking pin or bolt for securing inclined stabilizer arms, as
 will be described hereafter. Also provided along the lower portion of the
 mast and along one of the elongated columns is a mounting bracket 110
 having an opening therein for purposes of receiving a locking pin or bolt
 for securing a secondary stabilizer arm as will also be described.
 The top head rotary drive and mast of the present invention is designed to
 be pivotally mounted to the conventional derrick 23. In this respect, the
 assembly includes a pair of upper support arms 120 which are pivotally
 mounted in parallel relationship with respect to one another at 121 to an
 upper portion of the mast and which are adapted to be pivotally mounted to
 the derrick at pivot points 122. The support arms are provided on each
 column 47 and 48 of the mast 45. The length of the support arms 120 is
 designed to allow the mast to be deployed to an appropriately spaced
 position rearwardly of the cable rig, as previously described, to permit
 drilling with the drilling hole being aligned with the upper portion of
 the derrick 23 so that cable tools of the conventional rig are
 appropriately aligned for use in a bore hole after the top head rotary
 drive and mast assembly is pivoted to an out-of-way or stored position.
 To initially assemble the top head rotary drive and mast to the derrick 23
 of the drill rig, the cable 33 of the drill rig is connected by way of the
 hook 73 to the bail 98 extending from the crown 87 of the mast.
 Thereafter, the mast is raised utilizing the controls associated with the
 cable rig. With the mast extended adjacent to the derrick, the mast is
 lowered until the support arms 120 are horizontal and generally
 perpendicular to the mast and to the derrick. Thereafter, a mark is made
 for the proper placement of brackets for providing the pivot points 122 on
 the derrick. After the brackets are attached, the support arms are secured
 to the derrick as previously described allowing a pivotal movement of the
 mast relative to the derrick.
 The drill rig is further provided with a pair of spaced outer brackets 130
 (only one being shown in FIGS. 12 and 13) which are vertically spaced so
 as to be above the brackets 105 and 106 associated with the base of the
 mast. Further, a second bracket 132 is provided on the frame of the drill
 rig which is designed to be generally aligned with the bracket 110 on the
 mast. With the mast being lowered to the position shown in FIG. 13, a
 first pair of inclined stabilizer arms 134 are secured between the
 brackets 105 and 106 and the brackets 130 of the drill rig. It should be
 noted that the stabilizer arms 134 are angled upwardly from the mast
 toward the drill rig. The orientation of the stabilizer members is
 provided so as to offset forces developed along the length of a drill
 string that might otherwise tend to lift the mast from the bore hole
 during drilling. To prevent any possible rotation of the stabilizer arms
 134, an upper stabilizer arm 135 is mounted between the bracket 110 on the
 mast and the bracket 132 on the drill rig. As shown, the angle of the
 upper stabilizer arm is different than the angle of inclination of the
 inclined stabilizer arms 134. In the preferred embodiment, the orientation
 is such as to be generally perpendicular between the mast and the drill
 rig creating a rigid triangular structure, as is shown in FIG. 13, when
 the top head rotary drive motor is being used to advance a drill string.
 The stabilizer arms 134 and 135 are preferably "Patterson" turnbuckles
 thereby allowing flexibility in length adjustment. The stabilizers are
 preferably mounted utilizing removable pins to the brackets to which they
 are supported thereby allowing quick removal of the stabilizer arms when
 it becomes necessary to elevate or move the top head rotary drive and mast
 assembly to the stored position, as such movement would not be possible
 with the stabilizer arms in place.
 It should be noted, that although two upper support arms have been
 described with respect to the preferred embodiment, it is possible, in
 some instances, that a single support arm could be used especially if the
 support arm includes a yolk type outer end. It is the specific purpose of
 the support arms to provide stability and, therefore, the two support arms
 shown in the drawing figures are preferred. In a like manner, it is
 possible that only a single stabilizer arm 134 may be used and be within
 the teachings of the present invention although providing stabilizer arms
 on either side of the mast is preferred, as is shown in the drawing
 figures.
 When it is desirable to remove the rotary drive head and utilize the cable
 drilling or hoist elements associated with the cable rig, the present
 invention provides a unique manner for utilizing the control device 75 for
 elevating the assembly from the deployed position of FIG. 13 to an upper
 stored position, as shown in FIG. 15.
 In this respect, the present invention provides at least one, and
 preferably two, restraint elements 140 which extend from lower ends
 secured about hooks 142 provided on the holding plate 44. As shown, the
 hooks 142 extend from the rear surface of the holding plate on opposite
 sides thereof. The restraint elements may be formed from chains or heavy
 cable having looped outer ends 143 for fitting over the hooks 142. The
 opposite ends thereof extend to supports 150 secured on opposite sides of
 the derrick.
 With specific FIG. 14, the top head rotary drive and mast assemble 10 is
 shown as being oriented in a position for drilling relative to the derrick
 23. With the restraint elements 140 in place, the control device or
 hydraulic cylinder 75 is operated so as to lower the holding plate 44 and
 thus the top head rotary drive 40 downwardly toward the guide table 48.
 The restraint elements 140 will limit the degree of downward movement of
 the holding plate and prevent movement at a given point. Thereafter, the
 operation of the control device to lower the holding plate will act to
 actually raise the mast because of the movement of the cables extending
 between the control device and the holding plate. As the mast elevates, it
 will pivot about the support arms 120 until it comes into abutting
 relationship with respect to the derrick, as shown in FIG. 11. As the mast
 is raised relative to the holding plate the restraining elements 140 will
 remain taut. The mast will be held in the raised position by the action of
 the hydraulic system associated with the control device thus insuring that
 the mast will be retained in the raised position.
 To deploy the mast from the raised position and with specific reference to
 FIGS. 11-13, with the mast against the derrick, the control device 75 is
 operated to raise the holding plate as indicated by the arrows in FIG. 12.
 As this occurs, the mast will begin to fall under its own weight toward
 the ground being stabilized by the support arms 120. Lateral movement of
 the mast is limited by the safety line or chain 100. To control and limit
 swinging motion of the mast, a guide cable or chain 101 is connected
 between bracket 102 and 103 secured to the mast and derrick, respectively,
 at a distance slightly above the guide table. The guide cable as shown is
 generally not greater than approximately 39 inches in length to permit the
 necessary deployment of the mast. With the mast positioned slightly above
 the ground, the cable 33 of the drill rig may be connected to the
 connector extending from the guide table and slightly elevated thereby
 taking the full weight of the mast essentially off of the support arms.
 Thereafter, the mast may be pulled outwardly to its full extent and
 lowered to the position shown in FIG. 13. During this motion, the
 restraint elements 140 will automatically drop free of the hooks on the
 holding plate to a position shown in FIG. 13 and will thus not be in a
 position to restrict the downward movement of the holding plate so that
 the top head rotary drive may be utilized in its capacity for drilling
 purposes. Thereby, the restraint elements are automatically disconnected
 from the top head rotary drive and mast assembly during the deployment of
 the mast relative to the derrick.
 In view of the foregoing, the present invention provides a top head rotary
 drive and mast assembly which may be easily connected to and deployed
 relative to a derrick of a conventional cable or other drill rig such that
 the mast may be moved to an appropriate drilling position utilizing the
 top head drive for movement of a drill string. Thereafter the top head
 rotary drive can easily be disconnected from the drill string and the mast
 raised utilizing the control device associated with the holding plate. The
 mast is lifting toward the derrick and positively retained in the raised
 out-of-way position so that the conventional cable equipment and cable
 lines of the drill rig may be used to support or otherwise work with the
 drill string or can be used to drill or drive well casing in a
 conventional manner.
 As opposed to using the control device 75 for elevating and lowering the
 mast described above with respect to the preferred embodiment, other
 devices may be used to lower and raise the mast to and from it's deployed
 position. In this respect, and as shown in dotted line on FIG. 12, a
 hydraulic or electric winch 145 may be mounted to the derrick and includes
 a cable 146 secured to the mast, such as to the bail 98 at the crown of
 the mast. Appropriate controls, not shown, could be used to raise and
 lower the mast using the winch.
 As previously discussed, the motors 43A and 43B for driving the top head
 rotary drive 40, the control device in the form of a hydraulic cylinder 75
 and the holding wrench 66 are preferably controlled by hydraulic fluid. To
 convert the cable rig to provide the necessary source of fluid power, a
 double pump P1 and P2 is directly mounted to a drive shaft (not shown) of
 a diesel or gas engine 200 mounted on the chassis of the rig, as shown in
 FIG. 10 and with reference to the hydraulic circuit shown in FIG. 16. The
 pumps P1 and P2 are connected to a control panel 202 mounted at the rear
 of the rig as shown in FIGS. 5 and 10. The pumps are connected to a 50
 gallon source of hydraulic oil 204 shown in the fluid circuit FIG. 16. The
 reservoir is mounted on the opposite side of the rig from the pumps shown
 in FIG. 10 and, therefore, is not depicted in the drawings.
 Pump P2 is connected through a first branch of the hydraulic fluid circuit
 205 and through a pressure compensated flow control valve 206 to manual
 control valves 207 and 208 which are controlled by levers 209 and 210,
 respectively. The valves 207 and 208 are used to control the operation of
 the hydraulic motors 43A and 44B of the top head rotator 40. A pressure
 release valve 212 is shown as being mounted between the valves 207 and 208
 and the pressure compensated of flow control valve 206. The fluid circuit
 205 is controlled by the control valve 206 and is used to provide maximum
 drilling speed and torque to the motors 43A and 43B.
 Pump P1 is shown as being connected in a second branch of the hydraulic
 fluid circuit 220 and through a pressure relief valve 222 to a flow
 diverter valve 224 which is manually controlled by a lever 225. In a first
 position of the diverter valve 224, hydraulic fluid is provided to a
 sub-circuit 226 to a series manually operable valves 227, 228, 229 and 230
 each of which is manually controlled by operating levers 231, 232, 233 and
 234, respectively. Each of the valves 227-230 is connected in a fluid
 circuit to control the deployment and retraction of the hydraulic
 stabilizing cylinders 26 which are mounted on the cable rig and which are
 utilized to stabilize the rig during drilling
 By manually switching the diverter valve 224 to a second position,
 hydraulic fluid is provided to sub-circuits 240A and 240B by way of which
 hydraulic fluid is provided in sub-circuit 204A through a pressure relief
 valve 242 to a series of manually control valves 244, 245, 246, and 247
 which are controlled utilizing the manual levers 231, 233, and 234
 respectively. Valve 234 is used to control the operation of the control
 device or the hydraulic cylinder 75 whereas valve 245 is utilized to
 control the operation of the holding wrench 66. Valve 246 is connected to
 operate an air valve cylinder 250 which provides high pressure air through
 the rotator head for purposes of providing high pressure air to a drill
 string. Valve 247 is connected through a control valve 248 which is
 connected to a source of water 252. The water is provided for drilling
 purposes and a hose 255 is connected to the rotator head in order to
 introduce water through the drill string when required. Sub-circuit 240B
 is shown as being connected to the top head rotary drive motors 43A and
 43B through control valve 208. Hydraulic fluid is supplied at normal
 operating pressure through this sub-circuit to the motors 43A and 43B.
 During operation of the control device or feed cylinder 75, the amount of
 pressure, referenced as a hold-down pressure, is regulated by the
 hold-down valve 242 and a second hold-down valve 260. These valves control
 the amount of pressure in the hydraulic circuit.
 To obtain maximum pressure for drilling speed and torque at motors 43A and
 43B, the diverter valve 224 is manually moved to a third intermediate
 position such that hydraulic fluid is recycled to the P.sub.2 through line
 260 from which the fluid is directed to the valves 209 and 210 controlling
 the top head drive motors 43A and 43B.
 The foregoing description of the preferred embodiment of the invention has
 been presented to illustrate the principles of the invention and not to
 limit the invention to the particular embodiment illustrated. It is
 intended that the scope of the invention be defined by all of the
 embodiments encompassed within the following claims and their equivalents.