Patent Publication Number: US-8118118-B2

Title: Modular rotary drill head

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is a continuation application of U.S. patent application Ser. No. 12/239,468, filed on Sep. 26, 2008, entitled “Modular Rotary Drill Head.” The contents of each of the above-referenced application are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. The Field of the Invention 
     The present invention relates to drill heads and to rotary drill heads in particular. 
     2. The Relevant Technology 
     Drilling rigs are often used for drilling holes into various substrates. Such drill rigs often include a drill head mounted to a generally vertically oriented mast. The rig often includes mechanisms and devices that are capable of moving the drill head along at least a portion of the mast. The drill head often further includes mechanisms that receive and engage the upper end of a drill rod or pipe. The drill rod or pipe may be a single rod or pipe or may be part of a drill string that includes a cutting bit or other device on the opposing end, which may be referred to as a bit end. 
     The drill head also applies a force to the drill rod or pipe which is transmitted to the drill string. If the applied force is a rotational force, the drill head may thereby cause the drill string rotate within the bore hole. The rotation of the drill string may include the corresponding rotation of the cutting bit, which in turn may result in cutting action by the drill bit. The forces applied by the drill head may also include an axial force, which may be transmitted to the drill string to facilitate penetration into the formation. 
     In many instances, specialized drill heads are utilized for differing applications. As a result when conditions change, a different drill head if not an entirely different drill rig is used, thereby increasing capital costs and/or down time. 
     The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced. 
     BRIEF SUMMARY OF THE INVENTION 
     A modular base assembly for a rotary drill head can include a drive flange assembly having a tubular drive shaft configured to engage at least a lower drive interface, a gear housing supporting the drive flange assembly, and a plurality of interchangeable gear pinions selectively coupled to the drive flange assembly. 
     A modular rotary drill head system can include a modular base assembly having a drive flange assembly having a tubular drive shaft configured to engage at least a lower drive interface, and a gear housing supporting the drive flange assembly, a plurality of drive motor assemblies, and a plurality of interchangeable gear pinions coupled to the drive motor assemblies, the gear pinions being configured to be interchangeably coupled to the gear housing. 
     A drilling system can include a sled assembly having a modular rotary drill head system, that includes a modular base assembly including a drive flange assembly having a tubular drive shaft configured to engage at least a lower drive interface, a gear housing supporting the drive flange assembly, a plurality of drive motor assemblies, and a plurality of interchangeable gear pinions coupled to the drive motor assemblies, the gear pinions being configured to be interchangeably coupled to the gear housing. 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential characteristics of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To further clarify the above and other advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1  illustrates a drilling system having a modular rotary drill head according to one example; 
         FIG. 2A  illustrates a perspective view of a modular rotary drill head according to one example; 
         FIG. 2B  illustrates a cross-sectional view of the modular rotary drill head taken along section  2 - 2  of  FIG. 2A ; 
         FIG. 2C  illustrates a plan view of the modular rotary drill head of  FIG. 2A ; 
         FIG. 3  illustrates an elevation view of a modular rotary drill head system according to one example. 
         FIG. 4  illustrates a double-head drilling system according to one example. 
         FIG. 5  illustrates modular rotary drill head of  FIG. 2A-2C  in which the drive motors have been interchanged. 
     
    
    
     Together with the following description, the Figs. demonstrate non-limiting features of exemplary devices and methods. The thickness and configuration of components can be exaggerated in the Figures for clarity. The same reference numerals in different drawings represent similar, though not necessarily identical, elements. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In at least one example, a modular rotary drill head includes a modular base assembly that includes a gear housing and a large diameter, hollow drive shaft. The gear housing can include interchangeable gear wheels and drive pinions that are configured to drive the drive shaft. Such a configuration may allow the drill head to operate with different drive motors, thereby allowing for interchangeability of drive motors on a single rotary drill head. The ability to interchange driver motors can allow the drill head to operate over a wide range of torques and/or rotational speeds. 
     Further, the configuration of the drive shaft may further allow the modular rotary drill head to operate in a variety of conditions. For example, the head may be used in deep hole drilling, such as Geothermal drilling, as the large diameter shaft and axial bearings are able to withstand large axial loads. 
     The modular rotary drill head can be configured to allow the gear housing to float as the modular rotary drill threads and/or unthreads tubular threaded members, such as drill rods and casing. Such a configuration can allow the gear housing to move during the unscrewing and screwing process of the rods and casings, which can reduce the stresses on the threaded portion of the tubular threaded members. Reducing the stresses on the threaded portions can in turn result in less wear on the threads. As used herein, the terms bottom, lower, and below will be used to describe a portion of a component or system that is located toward the bit end of the system while top, upper, and above will be used to describe a component or system that is located on an opposing side of the system or component. 
       FIG. 1  illustrates a drilling system  100  that includes a sled assembly  105  and a drill head  110 . The sled assembly  105  can be coupled to a mast  120  that in turn is coupled to a drill rig  130 . The drill head  110  is configured to have one or more tubular threaded member  140  coupled thereto. Tubular threaded members can include, without limitation, drill rods and rod casings. For ease of reference, the tubular threaded member  140  will be described as a drill rod. The drill rod  140  can in turn be coupled to additional drill rods to form a drill string  150 . In turn, the drill string  150  can be coupled to a drill bit  160  or other down-hole tool configured to interface with the material to be drilled, such as a formation  165 . 
     In at least one example, the drill head  110  illustrated in  FIG. 1  is configured to rotate the drill string  150  during a drilling process. In particular, the drill head  110  may vary the speed at which the drill head  110  rotates. In particular, the rotational rate of the drill head and/or the torque the drill head  110  transmits to the drill string  150  may be selected as desired according to the drilling process. For example, the drive motors, pinions, and/or gear wheels may be interchanged to provide the rotational rate and/or torque desired to suit different drilling applications. 
     Further, the sled assembly  105  can be configured to translate relative to the mast  120  to apply an axial force to the drill head  110  to urge the drill bit  160  into the formation  165  during a drilling operation. In the illustrated example, the drilling system  100  includes a chain-drive assembly  170  that is configured to move the sled assembly  105  relative to the mast  120  to apply the axial force to the drill bit  160  as described above. As will be discussed in more detail below, the drill head  110  is can be configured in a number of ways to suit various drilling conditions. 
     In at least one example, the drill head  110  is coupled to drill rod  140  by way of interchangeable interface  180 . The interchangeable interface  180  in turn can be operatively associated with a drive flange assembly (not shown), which in turn can be driven by a drive shaft  190 . The drive shaft  190  can have a relatively large diameter inner bore. Such a configuration may allow the drive shaft  190  to transfer high-torque loads. Further, such a configuration may accommodate a large range of additional drill components, such as second drive heads and/or other components. 
     One basic configuration of a rotary drill head system will first be described in which one exemplary set of components have been assembled to a modular base assembly. The functionality of the rotary drill head system in such a configuration will then be described, followed by a description of interchanging various components. 
     As illustrated in  FIG. 2A , a rotary drill head system  200  includes a modular base assembly  205 . The modular base assembly  205  includes a gear housing  210  that supports a drive flange assembly  230 . The gear housing  210  is configured to provide a base to which one or more drive motor assemblies, such as drive motor assemblies  250 ,  250 ′, and  250 ″ (not shown), can be interchangeably coupled. As will be described in more detail below, the drive motor assemblies  250 ,  250 ′,  250 ″ may be exchanged in groups, such that the drive motor assemblies  250 ,  250 ′,  250 ″ can be exchanged as a group for additional drive motor assemblies. The drive motor assemblies  250 ,  250 ′, and  250 ″ are operatively associated with the drive flange assembly  230  to provide motive force to rotate a drill rod or other components. Further, in at least one example, the modular base assembly  205 , and the gear housing  210  in particular, is configured to provide thread compensation to reduce wear associated with threading and/or unthreading drill rods from the rotary drill head system. 
     The gear housing  210  can be operatively associated with a sled mount assembly  212 . The sled mount assembly  212  includes a base  214  having at least one upper tab  216 A and at least one lower tab  216 B. The upper tab  216 A and lower tab  216 B shown extend away from the base  214 . One or more rails  218  extend at least partially between the upper and lower tabs  216 A,  216 B. In at least one example, the rails  218  pass through the gear housing  210 . Further, at least a portion of the gear housing  210  is located between the upper and lower tabs  216 A,  216 B. 
     The rails  218  constrain the gear housing  210  from rotating relative to an axis generally parallel to the base  214  while the upper and lower tabs  216 A,  216 B bound the axial movement of the gear housing  210 . As will be discussed in more detail with reference to the functionality of the rotary drill head system  200 , floating the entire gear housing  210  can allow the rotary drill head system  200  to translate to reduce thread wear associated with coupling/decoupling a threaded rod tubular member from the rotary drill head system  200  by rotating the drive flange assembly  230  with the drive motor assemblies  250 . 
     Additionally, the drive flange assembly  230  is configured to have additional components interchangeably secured thereto. These components can include components located above and/or below the drive flange assembly  230 . The drill head assembly  200  may also include an optional lubrication assembly  270  associated with the modular base assembly  205 . 
     In the illustrated example, the gear housing  210  generally includes a top portion  210 A, a bottom portion  210 B, and a peripheral portion  210 C generally defining a compartment. The gear housing  210  can further include an access cover  225  removably coupled to the peripheral portion  210 C. Such a configuration may provide ready access to the compartment and the components positioned therein. 
       FIG. 2B  illustrates a cross-sectional view of the modular rotary drill head system  200  taken along section  2 B- 2 B of  FIG. 2A . As shown, at least part of the drive flange assembly  230  can be located at least partially within the compartment. The drive flange assembly  230  can include a drive shaft  232  having an upper portion  232 A and a lower portion  232 B. In at least one example, the drive shaft  232  has an inner diameter up to about 12 cm or larger. An upper flange mount  234 A may be secured to the top portion  232 A while a lower flange mount  234 B may be secured to the lower portion  232 B. A driving flange  236  is shown secured to the lower portion  232 B. 
       FIG. 2C  illustrates a plan view of the modular rotary drill head system  200  in which part of the top portion  210 A of the gear housing  210  has been removed for ease of reference. As illustrated in  FIG. 2C , the drive shaft assembly  230  can also include a gear wheel  238  secured to the drive shaft  232  in any suitable manner. For example, the gear wheel  238  may be secured to the drive shaft  232  by one or more keys  240 . 
     As illustrated in  FIG. 2B , the drive shaft  232  can be supported within the gear housing  210  by one or more bearings. In particular, the drive shaft  232  may be supported by upper and lower needle bearings  242 A,  242 B and/or upper and lower axial bearings  244 A,  244 B, such as axial-cylinder roller bearings. Such a bearing configuration may allow the rotary drill head system  200  to withstand the high axial forces associated with operating a heavy drill string at great depths. 
     As previously introduced, the drive shaft assembly  232  is operatively associated with one or more drive motor assemblies  250 ,  250 ″ and  250 ′ ( FIG. 2A ). In the illustrated example, each of the drive motor assemblies  250 ,  250 ′,  250 ″ are substantially similar. In other examples, modular rotary drill head systems may include drive motor assemblies with different configurations. For ease of reference, similar drive motor assemblies  250 ,  250 ′,  250 ″ will be described relative to a drive motor assembly  250 . It will be appreciate that the description may also be applied to drive motor assemblies  250 ′ and  250 ″. 
     Continuing with reference to  FIGS. 2B and 2C , the drive motor assembly  250  can include a drive motor  251 . The drive motor  251  can be coupled to the gear housing  210  by a housing flange  252 . The drive motor  251  is further operatively associated with a gear pinion  254 . The gear pinion  254  is supported on a top portion  254 A by the drive motor  251  and on a bottom portion  254 B by a bearing assembly  256 . 
     In the illustrated example, the bearing assembly  256  includes a flange mount  258  that configured to be secured to a bottom portion  210 B of the gear housing  210 . The bearing assembly  256  further includes a bearing  260 , such as a radial bearing, that is operatively associated with the flange mount  258 . The bearing  260  provides rotating support for the gear pinion  254  as the gear pinion  254  is driven by the drive motor  251 . 
     As previously introduced, the drive motor assembly  250  is configured to be interchangeably coupled to the drive shaft assembly  230 . In the illustrated example, when the drive motor assembly  250  is assembled to the gear housing  210 , the gear pinion  254  engages the gear wheel  238 . As a result, when the drive motor  251  is actuated to drive the gear pinion  254 , the gear pinion  254  drives the gear wheel  238 . The gear wheel  238  in turn is secured to the drive shaft  232  such as gear wheel  238  rotates it turns the drive shaft  232 . 
     As also illustrated in  FIGS. 2B and 2C , the modular rotary drill head system  200  can include a lubrication assembly  270  that is configured to lubricate one or more of the bearings  260  and/or other bearings described above. In the illustrated example, the lubrication assembly  270  generally includes a lubrication pump  272  that distributes lubricant through a series of conduits  274 ,  274 ′. For ease of reference, conduit  274  will be discussed as providing lubrication to bearing  260 . It will be appreciated that this discussion can be equally applicable to the lubrication of the other bearings. 
     Continuing with reference to  FIGS. 2B and 2C , the conduits  274  can be operatively associated with an outlet  276  that is positioned in proximity to the bearing  260 . As a result, the lubrication pump  272  can pump lubricant through the conduits  274  and outlet  276  onto the bearing  260 . The lubrication assembly  270  can be configured to lubricate bearings, such as bearings  260 , as the rotary drill head system  200  operates, thereby reducing down-time associated with manually lubricating bearings. 
     To this point, a rotary drill head system  200  has been illustrated and described that includes an exemplary set of drive motor assemblies  250 ,  250 ′,  250 ″ coupled to the modular base assembly  205 .  FIG. 3  illustrates additional components secured below the drive flange assembly  230 . In the illustrated example, a drill rod interface  300  is shown coupled to the driving flange  236 . The drill rod interface  300  can be a threaded, pin-type interface that is configured to rotate into and out of engagement with a corresponding box-end of a drill rod  310 . 
     As previously introduced, the gear housing  210  is configured to float relative to the sled mount assembly  212 . In particular, as illustrated in  FIG. 3 , one or more bushings  305  may be positioned within the gear housing  210  to support and guide the gear housing  210  on the rails  218  as the gear housing  210  translates relative to the rails  218 . Such a configuration allows the rotary drill head system  200  to float while threading and unthreading the drill rod  310  from the drill rod interface  300 . In particular, in the illustrated example, while drilling a formation and/or tripping a drill rod  310  downward, an upper portion  210 A of the gear housing  210  contacts the upper tab  216 A. Similarly, while lifting a drill rod  310 , the lower portion  210 B of the gear housing  210  contacts the lower tab  216 B. 
     Accordingly, as a drill rod  310  is raised and gripped to allow the drill rod interface  300  to rotate relative to the drill rod  310  the lower portion  210 B of the gear housing  210  is often in contact with or located proximate to the lower tab  216 B. As the rotary drill head system  200  rotates the drill flange  300  to unthread the drill rod  310 . Unthreading the drill rod  310  from the drill rod interface results in relative separation between the drill rod interface  300  and the drill rod  310 . As previously introduced, the gear housing  210  is configured to freely translate relative to the sled mount assembly  212 . This movement may be referred to as thread compensation. Accordingly, as the drill rod  310  is thus unthreaded from the drill rod interface  300 , the rotary drill head system  200  is able to move away from the drill rod  310  thereby reducing localized stresses on the threads of the drill rod  310  and the drill rod interface  300 . 
     While a drill rod interface  300  is shown as being coupled to the driving flange  236 , it will be appreciated that other components and/or systems may also be coupled to the driving flange  236 . For example, the driving flange  236  may be configured to receive other drilling equipment that can include, but is not limited to, a flushing head, a preventer, chuck, an ejection bell, and/or other drilling equipment by coupling a corresponding flange to the drilling equipment and then coupling that flange to the driving flange  236 . Further, the upper flange mount  234 A can be configured to have any number of drill components secured thereto in a similar manner. These components can include, without limitation, a central flushing head, a packing box, a RC flushing head, and/or other drilling equipment. 
     As previously introduced, the rotary drill head system  200  is configured to float relative to the sled mount assembly  212 . Such a configuration can provide thread compensation while at the same time allowing the drive shaft  232  to have both a large outer diameter as well as a relatively large inner diameter. A relatively large inner diameter may provide additional functionality for the rotary drill head system  200 . In particular, the relatively large inner diameter may allow relatively larger components, such as those used in double drilling or other similar operations, to pass through the drive shaft  232 . For example, double head drilling, jet grouting, RC-Drilling and/or other similar operations may be performed by combining an additional drill head or a drifter head on the same mast and/or sled assembly, as illustrated in  FIG. 4 , represented schematically as second drill head  400  in  FIG. 4 . 
     While one type of double head drilling configuration is illustrated in  FIG. 4 , it will be appreciated that other types of double head configurations can be readily coupled to the modular base assembly  205 . Further, it will be appreciated that several modular base assemblies  205  can be combined as desired to perform double drilling operations. Each of these configurations can be assembled to a single modular base assembly  205  by interchanging components as desired for a particular application. Accordingly, the modular base assembly  205  is configured to have additional components coupled thereto from both above and below. 
     Further, the modular base assembly  205  is configured to have any number of drive motor assemblies coupled thereto. As previously discussed and as illustrated in  FIGS. 2B and 2C , the modular base assembly  205  includes a gear housing  210  to which drive motor assemblies  250 ,  250 ′,  250 ″ can be coupled. As illustrated in  FIG. 5 , drive motor assemblies  550 ,  550 ′,  550 ″ can be exchanged for drive motor assemblies  250 ,  250 ′,  250 ″. In particular, referring again briefly to  FIGS. 2B and 2C , drive motor assemblies  250 ,  250 ′,  250 ″ may be removed by decoupling the housing flange  252  from the upper portion  210 A of the gear housing  210  and decoupling the bearing assembly  256  from the bottom portion  210 B of the gear housing  210 . 
     Thereafter, referring again to  FIG. 5 , bearing assemblies  556  can then be secured modular base assembly  205  by securing the flange mount  558  to the corresponding bottom portion  210 B of the gear housing  210 . The flange mount  558  is configured to locate bearing  560  and the associated gear pinion  554  such that the gear pinion  554  engages the gear wheel  238 . The gear pinion  552  can be positioned relative to the bearing before or as the housing flange  552  with the drive motor  551  is secured to the upper portion  210 A of the gear housing. The drive motor  551  and/or the gear pinion  552  may provide different rotational and/or torque performance ranges relative to those associated with drive motor assembly  250 . 
     Further, any number of additional drive motor assemblies may be interchanged with the modular base assembly  205  that include any number of different rotational and/or torque ranges. Accordingly, the rotary drill head system  200  can be readily configured to provide torque and/or rotational performance as desired by interchanging drive motor assemblies with the modular base assembly  205 . Further, interchanging drive motor assemblies can be performed as desired while the modular base assembly  205  remains coupled to a drill mast. In addition to providing versatility, such a configuration may reduce down-time associated with changing drive motors. 
     The drive motors  251 ,  551  can have any configuration desired. In at least one example, the drive motors can be hydraulic motors, such as Geroler, Geroter, and/or valve in star (VIS) type hydraulic motors. 
     The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.