Abstract:
A drill stem connection system and method is shown that provides a secure hold on drill stem surfaces while unscrewing a threaded connection. Two lever arm components are adjustable to a number of possible orientations to allow for fitting the drill stem wrench in tight spaces. Concentric rotation of lever arm components facilitates connection of the lever arm components together. Configurations and methods shown provide a stable and powerful tool to loosen threaded drill stem effectively.

Description:
RELATED MATTERS 
       [0001]    This patent application is a Continuation of U.S. application Ser. No. 12/612,416, filed Nov. 4, 2009 and issued on Jan. 25, 2011 as U.S. Pat. No. 7,874,370, which is a Continuation of U.S. application Ser. No. 11/925,353, filed on Oct. 26, 2007 and issued on Dec. 8, 2009 as U.S. Pat. No. 7,628,212, which claims the benefit of priority, under 35 U.S.C. Section 119(e), to U.S. Provisional Patent Application Ser. No. 60/863,073, filed on Oct. 26, 2006, which applications are incorporated herein by reference in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    This invention relates to coupling and decoupling drill stem sections. Specifically, this invention relates to tools and methods for coupling and decoupling sonde housings or other drill stem components for use with horizontal directional drills. 
       BACKGROUND 
       [0003]    Directional drilling is a useful technique for several procedures such as utility installation, etc. One common type of directional drilling is horizontal directional drilling (HDD), where a drill stem is extended essentially horizontally to form passages underground without the need for a trench. Drill heads in directional drilling typically have a feature which causes the drill head to steer in one direction when forced ahead by a drilling device. During a boring operation, pressure is applied through a drill stem from behind to the drill head. During a straight bore, the drill stem is typically rotated at a regular rate so that on average, only straight ahead drilling is accomplished. In order to steer a drill head, the rotation is temporarily stopped, and the drill head is allowed to steer in the desired direction. Once the steering maneuver is complete, the drill head is again rotated at a regular rate for straight ahead drilling. 
         [0004]    In many HDD operations, an electronic transmitter called a sonde is coupled to a distal end of the drill stem. Signals transmitted from the sonde are detected by a receiver carried by an operator above ground. Various characteristics of the detected signal are then used to indicate a location and orientation of the distal end of the drill stem. This information can then be used to steer the drill stem in a desired direction. 
         [0005]    When a bore is completed, typically the sonde and associated sonde housing are removed and a pipe, cable, transmission line is coupled to the drill stem to be pulled into the bore as the drill stem is pulled back. A common attachment between the sonde housing and the drill stem is a threaded connection such as a tapered thread as known in the industry. Currently large pipe wrenches are used to loosen the threaded connection, however use of large pipe wrenches within an exit pit of a horizontal bore presents a level of safety risk. Large torque forces can be necessary to loosen the threaded joint which can make breaking the connection difficult. What is needed is an improved wrench, connection system and method that makes connection and disconnection of drill stem joints easier, and improves safety. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1A  shows a drill stem and wrench according to an embodiment of the invention. 
           [0007]      FIG. 1B  shows drill stem components according to an embodiment of the invention. 
           [0008]      FIG. 2  shows an exploded view of a wrench according to an embodiment of the invention. 
           [0009]      FIG. 3  shows an isometric view of a drill stem connection system according to an embodiment of the invention. 
           [0010]      FIG. 4  shows another isometric view of a drill stem connection system according to an embodiment of the invention. 
           [0011]      FIG. 5  shows another exploded view of a wrench according to an embodiment of the invention. 
           [0012]      FIG. 6  shows an isometric view of a wrench as shown in  FIG. 5  according to an embodiment of the invention. 
           [0013]      FIG. 7  shows one drilling method of operation according to an embodiment of the invention. 
           [0014]      FIG. 8  shows another method of operation according to an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown, by way of illustration, specific embodiments in which the invention may be practiced. In the drawings, like numerals describe substantially similar components throughout the several views. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural, mechanical or logical changes, material choice, etc. may be made without departing from the scope of the present invention. In the following description the term “breaking” unless otherwise noted refers to an operation of loosening a threaded connection where higher levels of starting friction forces are overcome, and lower sliding friction forces are then required to finish unscrewing a threaded connection. Unless otherwise noted, “breaking” does not refer to actually damaging any component. 
         [0016]      FIG. 1A  shows a wrench  100  and sections of drill stem  200  according to an embodiment of the invention. A first drill stem section  210  is shown coupled to a second drill stem section  220 . In one embodiment, the first drill stem section  210  includes a sonde housing, and the second drill stem section  220  includes a starter shaft. Although a side loading sonde housing is within the scope of the invention,  FIG. 1A  illustrates an rear end loading sonde housing. 
         [0017]    In one embodiment the first drill stem section  210  includes a coupling  212  with engagement features  214 . In one embodiment, the coupling  212  is formed from a hard material such as tool steel.  FIG. 1A  illustrates a number of flats  214  as engagement features, although the invention is not so limited. Other engagement features include holes, splines, etc. Likewise in one embodiment the second drill stem section  220  includes a coupling  222  with engagement features  224 .  FIG. 1A  illustrates a number of splines  224  as engagement features on the coupling  222 . A wrench  100  is shown adjacent to the drill stem  200  that will be discussed in more detail below. 
         [0018]      FIG. 1B  shows the first drill stem section  210  separated from the second drill stem section  220 . In  FIG. 1B , a threaded portion  226  is visible. In one embodiment, the threaded portion  226  includes a tapered thread as is common in the HDD industry. Although a male thread is shown on the second drill stem section  220  and a corresponding female thread is included on the first drill stem section, the invention is not so limited. One of ordinary skill in the art having the benefit of the present disclosure will recognize that the male and female threads could be reversed between the drill stem sections. 
         [0019]      FIG. 2  illustrates an exploded view of one embodiment of wrench  100  as illustrated in  FIG. 1A . The wrench  100  includes a first lever arm  110  and a second lever arm  120 . A first wrench jaw  111  is included at a distal end of the first lever arm  110  and a second wrench jaw  122  is included at a distal end of the second lever arm  120 . In one embodiment the first wrench jaw  111  includes at least a pair of parallel flat surfaces to engage at least two corresponding flats on a coupling. In one embodiment the second wrench jaw  122  includes one or more splines, likewise to correspond with a splined coupling. Although one wrench jaw is illustrated with flats and the other wrench jaw is illustrated with splines, the invention is not so limited. Other configurations include two jaws with flats, two jaws with splines, or other jaw configurations and combinations of jaw configurations. 
         [0020]    One advantage of using a number of splines on one or more of the wrench jaws includes more available options for wrench orientations. When breaking a drill stem joint within a confined space such as an exit pit, frequently only a limited number of wrench orientations will fit into the space available. Having multiple splines spaced around a perimeter of a wrench jaw provides multiple orientations, with a higher likelihood that an available orientation will work within the limited space. 
         [0021]    A slot  124  is shown in the second lever arm  120 . In one embodiment a shoulder bolt  130  and washer  132  are used to couple the second lever arm  120  to the first lever arm  110  through the slot  124  into a mating threaded hole  114 . In one embodiment, a pair of roll pins  150  line up adjacent to the second lever arm  120  and coordinate with the slot  124  and shoulder bolt  130  to form an axis of rotation between the first lever arm  110  and the second lever arm  120 . In one embodiment, the axis of rotation is substantially within a center of both wrench jaws. Roll pins, in one embodiment, line up with rounded portions of the second lever arm  120  to guide relative rotation between the first lever arm  110  and the second lever arm  120 . 
         [0022]    One advantage of such a configuration includes relative rotation between the first lever arm  110  and the second lever arm  120  that is concentric with the drill stem axis  201  as shown in  FIG. 3  and discussed below. Another advantage of such a configuration with the first lever arm  110  and the second lever arm  120  coupled together includes increased stability during a connection/disconnection operation. A connection such as shoulder bolt  130  and washer  132  keeps the first lever arm  110  and the second lever arm  120  in alignment with each other to provide a safe and powerful joint breaking force. 
         [0023]    An actuator  142  is also shown in  FIG. 2 . In one embodiment, the actuator  142  forces the first lever arm  110  apart from the second lever arm  120  to provide a joint breaking torque. In one embodiment, the actuator provides a mechanical advantage to amplify applied forces. The actuator  142  shown in  FIG. 2  includes a threaded member such as a jack screw. Although a jack screw is shown, the invention is not so limited. Other actuators include various threaded members, cams, hydraulics, etc. 
         [0024]    In one embodiment, a connector  140  with mating threads mounts to the second lever arm  120  while an end of the jack screw pushes against a pocket  116  in the first lever arm  110 . In one embodiment the connector  140  is optionally located in one of a plurality of holes  126  in the second lever arm  120 . The plurality of holes, along with starting location of the jack screw  142 , provides a large range of adjustability in starting angle between the first lever arm  110  and the second lever arm  120 . As discussed above, in conditions where working space is limited, it is desirable to have multiple options for starting angles. 
         [0025]      FIG. 3  shows an connection system  300  with a wrench  100  in place on a drill stem  200 . Only the coupling  212  of the sonde housing is shown attached to the starter shaft  220 . In a disconnection operation, the actuator  142  jack screw is threaded down against the first lever arm  110 . The first lever arm  110  is then rotated in relation to the second lever arm  120  to break the drill stem joint. In one embodiment, as discussed above, the axis of rotation between the first lever arm  110  and the second lever arm is substantially within the wrench jaws located on the respective lever arms. As shown in  FIG. 3 , in one embodiment the axis of rotation is substantially concentric with a drill stem axis  201 . Concentric rotation as described in selected embodiments allows the first and second lever arms  110 ,  120  to be coupled together for stability, while applying torque on axis with the drill stem  200 . 
         [0026]      FIG. 4  shows another view of the system  300  shown in  FIG. 3 . The relative rotation of the first lever arm  110  with respect to the second lever arm  120  is illustrated by arrow  160 . As can be seen in the Figure, the slot  124  and bolt  130  allow rotation, that is further guided by the roll pins  150 . 
         [0027]    In one embodiment, the starter shaft  220  further includes a number of inserts  228 . As shown in  FIG. 4 , in one embodiment, the inserts are located on a back side of the splines  224 . In one method of operation, the starter shaft  220  remains in place on the drill stem after the sonde housing  210  is removed. An advantage of including inserts such as tool steel or tungsten carbide inserts, includes better wear resistance of the splines  224  when withdrawing the drill stem  200  from the bore. 
         [0028]      FIG. 5  shows an exploded view of another embodiment of a wrench  500 . A first lever arm  510  and a second lever arm  520  are connected through shoulder bolts  532 ,  534  and  536 . The shoulder bolts ride in respective slots  522 ,  524  and  526  within the second lever arm  520 . Similar to embodiments described above, a jack screw actuator  512  is attached through a coupler  514  to the second lever arm  520  using hole  516 . 
         [0029]    The second lever arm  520  shown in  FIG. 5  further includes a number of grooves  540  within a jaw opening  524 . While four grooves  540  are shown, other embodiments include only one groove, or more than four grooves. Operation of the grooves  540  is described in more detail below. 
         [0030]      FIG. 6  shows the wrench  500  coupled to a drill stem joint. Similar to embodiments described above, the first lever arm  510  is rotated with respect to the second lever arm  520  using the jack screw  512 . The shoulder bolts  532 ,  534 , and  536  are shown providing a connection between the first lever arm  510  and the second lever arm  520  with an axis of rotation that is within the wrench jaws, and substantially concentric with the drill stem axis. 
         [0031]    Also shown in  FIG. 6  are a number of splines with grooved spacings  542  on one of the drill stem components. The grooved spacings  542  are alignable with one or more of the grooves  540 . Choosing which groove  540  and grooved spacing  542  to align provides multiple wrench orientation possibilities when starting a joint breaking or disconnecting operation. Once a grooved spacing  542  and a groove  540  are chosen, a key  550  is inserted into the aligned opening to transfer torque between the second lever arm  520  and the drill stem component. In one embodiment, the jaw opening  528  includes more than 180 degrees of material, such that the jaw opening  528  will pass over a slot  529  in the drill stem component, yet when engaged over the grooved spacings  542 , the jaw opening  528  is held laterally captive on the drill stem component. This configuration helps keep the second lever arm  520  in place over the splines and keeps the key  550  more securely engaged with the grooved spacings  542  and the grooves  540 . 
         [0032]      FIG. 7  shows one possible method of use according to an embodiment of the invention. In a horizontal drilling operation one method includes drilling a substantially horizontal bore using a directional drill with a sonde housing at a distal end of the drill stem. The method further includes disconnecting the sonde housing from the distal end of the drill stem using a wrench as provided in embodiments described above. For example, engaging a first wrench jaw of a first lever arm with the sonde housing, and engaging a second wrench jaw of a second lever arm with the drill stem. The first lever arm and the second lever arm are coupled together and are free to rotate about an axis substantially concentric with a drill stem axis. In the method, one further rotates the first lever arm with respect to the second lever arm using an actuator that provides a mechanical advantage to loosen a threaded joint between the sonde housing and the drill stem. Although the method describes an operation including a sonde housing and a component such as a starter shaft, the invention is not so limited. Other drill stem components in a drill stem joint are included within the scope of the invention. 
         [0033]    While a number of advantages of embodiments of the invention are described, the above lists are not intended to be exhaustive. Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiment shown. This application is intended to cover any adaptations or variations of the present invention. It is to be understood that the above description is intended to be illustrative, and not restrictive. Combinations of the above embodiments, and other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention includes any other applications in which the above structures and methods are used. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.