Abstract:
The present invention is directed to a rod string with a plurality of rod sections and a method for making up and breaking out the rod sections. The rod sections have corresponding pin and box ends, each having grooves and lands and an ungrooved portion. The rod sections can be connected by inserting the pin end into a box end and turning less than a full turn. A lock engagement mechanism having a first end and a second end is provided inside the rod sections and locks when the pin end is rotated into place. The lock engagement mechanism has a rotation stop which protrudes proximate the first end to prevent relative rotation of two rod sections until a key manipulates the lock engagement mechanism to retract the rotation stop.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of provisional patent application Ser. No. 61/662,107 filed on Jun. 20, 2012, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to rod sections for use with a multi-section drill string in underground boring applications. 
       SUMMARY OF THE INVENTION 
       [0003]    The invention is directed to a rod string comprising a plurality of rod sections. Each of the plurality of rod sections comprises a body, a pin end, a box end, and a lock engagement mechanism. The body has a first and a second end. The pin end comprises a plurality of grooves and lands at the first end of the body. The box end comprises a plurality of grooves and lands corresponding to the grooves and lands of the pin end at the second end of the body. The lock engagement mechanism is disposed within the body and moveable to a locked position when the pin end is placed within the box end of an adjacent rod section. 
         [0004]    In another embodiment the invention is directed to a lock engagement mechanism for a rod section. The lock engagement mechanism is moveable between a first position and a second position. The rod section comprises a pin end and a box end. The lock engagement mechanism comprises a body located within the rod section, a rotation stop, and a spring mechanism. The rotation stop is located proximate the pin end and protrudes from the pin end when the lock engagement mechanism is in the second position. The spring mechanism biases the lock engagement mechanism in the second position. 
         [0005]    In another embodiment, the invention is directed to a method for making up a rod string. The rod string comprises a plurality of rod sections each comprising a box end, a pin end, and a lock engagement mechanism. The method comprises advancing the pin end of a first rod section into a box end of a second rod section, rotating the first rod section less than a full turn, advancing a rotation stop into the box end of the second rod section, and contacting the lock engagement mechanism of the first rod section with the box end of the second rod section such that the first rod section is rotationally locked with the second rod section. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is an illustration of a horizontal directional drilling machine for use with the present invention. 
           [0007]      FIG. 2  is a perspective view of a rod section for use with the present invention. 
           [0008]      FIG. 3  is a cross-sectional view of the rod section of  FIG. 2  with an internally disposed lock engagement mechanism shown without cross-section. 
           [0009]      FIG. 4  is an end view of the box end of the rod section of  FIG. 2 . 
           [0010]      FIG. 5A  is a perspective view of the lock engagement mechanism of  FIG. 3  in a locked position. 
           [0011]      FIG. 5B  is a perspective view of the lock engagement mechanism of  FIG. 3  in an unlocked position. 
           [0012]      FIG. 6  is a cross-sectional side view of the lock engagement mechanism of  FIG. 3 . 
           [0013]      FIG. 7  is a side view of two rod sections being connected. 
           [0014]      FIG. 8  is a side view of two rod sections connected but not locked. 
           [0015]      FIG. 9  is a side view of two rod sections connected and locked together 
           [0016]      FIG. 10  is a perspective view of a key for use with the rod string of the present invention. 
           [0017]      FIG. 11  is a side view of two rod sections being disconnected through use of the key of  FIG. 10 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0018]    Devices such as horizontal directional drills (HDD), rod pusher/pullers and static pipe bursting machines all utilize a rod string that spans the length of new pipe or conduit to be installed. In the case of directional drills, the torsional load of rotating a cutting tool is often the cause of the greatest stress on the rod string. For this reason, directional drill rigs generally use threaded together rod sections. However, the threaded rod sections must have a device with sufficient mechanical overhead to produce enough torque to make or break the threaded connection. 
         [0019]    With reference now to the figures in general and  FIG. 1  in particular, shown therein is a horizontal directional drilling (HDD) machine  10  adapted to provide thrust and rotation to a rod string  12  made up of a plurality of individual rod sections  14 . HDD is shown for purposes of illustration. The rod sections  14  of this invention could be a pit launched machine, pipe pusher, or pipe puller. The rod string  12  is operatively connected to the HDD machine  10  at a first end  16 . A second end  18  of the rod string  12  comprises a boring tool  20  for underground boring purposes. 
         [0020]    With reference to  FIG. 2 , a first rod section  14  is shown in more detail. The rod section comprises a body  22 , a first end, or pin end  24  located at one end of the body, and a second end, or box end  26  located at an opposite end of the body. The pin end  24  comprises a grooved portion  28 , an ungrooved portion  30 , and a static rotation stop  32 . Preferably, the grooved portion  28  comprises a plurality of grooves and lands  34  comprising arcs having a common radius about a centerline  36  of the rod section  14 . The ungrooved portion  30  has no grooves and lands  34  and is preferably disposed closer to the centerline  36  than the grooved portion  28 . As shown, the ungrooved portion  30  allows the pin end  24  to have a greater width than height. As shown, the ungrooved portion  30  and grooved portion  28  of the pin end are discontinuous, providing two ungrooved portions and two grooved portions. 
         [0021]    The static rotation stop  32  is located against the body  22  of the rod section  14  and interacts with the box end  26  of an adjacent rod section as will be discussed in more detail below. A pin end alignment groove  38  is located on the body  22  proximate the pin end  24 . A box end alignment groove  40  is located on the body  22  proximate the box end  26 . 
         [0022]    With reference now to  FIG. 3 , the first rod section  14  is shown in cross section. As shown, the pin end  24  comprises openings  41 . The box end  26  is shown in further detail. 
         [0023]    The box end  26  comprises a counterbore of the pin end  24 . The box end  26  thus comprises a grooved portion  42  comprising grooves and lands corresponding to the grooved portion  28  ( FIG. 2 ) of a pin end of an adjacent, similarly formed rod section ( FIG. 7 ). The box end  26  (shown in greater detail in  FIG. 4 ) further comprises an opening  46  sized to fit the pin end  24  of an adjacent rod section. The box end  26  comprises a shoulder  48  to interact with the static rotation stop  32  ( FIG. 2 ) of the pin end  24  of an adjacent rod section and a lock engagement stop  49  to interact with a lock engagement mechanism  50  of an adjacent rod section as described below. The shoulder  48  preferably engages the static rotation stop  32  ( FIG. 2 ) when the grooved portion  42  of the box end is fully engaged with the grooved portion  28  of the pin end  24  of an adjacent, similarly formed rod section. The box end alignment groove  40  and the pin end alignment groove  38  ( FIG. 2 ) of an adjacent rod section align when the rod section  14  and adjacent rod section are fully engaged. 
         [0024]    Referring again to  FIG. 3 , the rod section  14  further comprises a lock engagement mechanism  50  located within a hollow section  51  of the body  22 . The lock engagement mechanism  50  comprises a spring mechanism (not shown), a first end  52  located proximate the box end  26  of the rod section  14  and a second end  54  located proximate the pin end  24  of the rod section. The first end  52  comprises a rod removal drive  56 . The second end  54  comprises a moveable rotation stop, or engagement point  58  located at the end of spring rods  60 . The engagement point extends through the openings  41 . The lock engagement mechanism  50  is rotatably moveable between a first, or locked position and a second, or unlocked position as will be described with reference to  FIG. 5A and 5B . As shown in  FIG. 3 , the engagement point  58  extends beyond the pin end  24  of the rod section  14  and thus the lock engagement mechanism  50  is in a locked position. 
         [0025]    With reference now to  FIG. 4 , the box end  26  is shown in greater detail. The pin end  24  ( FIG. 2 ) of an adjacent rod section is placed within the opening  46  of the box end  26  such that the engagement point  58  ( FIG. 3 ) is depressed against a wall  47  of the opening  46 . The adjacent rod section is then rotated until the static rotation stop  32  ( FIG. 2 ) interacts with the shoulder  48 . In the embodiment of  FIG. 4  the rod is rotated clockwise, though counterclockwise rotation may be utilized if desired. The engagement point  58  ( FIG. 3 ) then reaches the lock engagement stop  49  of the box end  26 , causing the engagement point  58  to extend into place and rotationally lock the rod section  14  and the adjacent rod section. 
         [0026]    With reference now to  FIGS. 5A and 5B , the lock engagement mechanism  50  is shown in further detail. In  FIG. 5A  the lock engagement mechanism  50  is shown in the locked position. The lock engagement mechanism further comprises a cartridge  62  and a cam  64 . The cartridge  62  houses the spring rods  60 . In the locked position, the cam  64  profile allows the engagement points to flex when contacting the wall of the opening  48  as described with reference to  FIG. 4  above. However, the spring rods  60  are biased to the locked position, so that the engagement points  58  will fully extend when the rod section  14  ( FIG. 3 ) is rotated such that the engagement points  58  are next to the lock engagement stop  49  ( FIG. 3 ). 
         [0027]    With reference to  FIG. 5B , the lock engagement mechanism  50  is shown in the unlocked position. Rotation of the rod removal drive  56  causes the cartridge  62  to rotate relative to the spring rods  60 . Rotation of the cartridge  62  relative to the spring rods  60  moves the spring rods within the earns  64  such that the spring rods are closer to a centerline of the lock engagement mechanism  50 . The engagement points  58  thus retreat from the lock engagement stop  49  ( FIG. 4 ) and allow the rod section  14  to rotate relative to an adjacent rod section. 
         [0028]    With reference to  FIG. 6 , the lock engagement mechanism  50  is shown in section, with spring rods  60  extending within the cartridge  62 . The spring rods  60  are rotationally locked to the rod removal drive  56  and not the cartridge  62 , allowing the rod removal drive to adjust the relative position of the spring rods  60  within the cams  64 . 
         [0029]    With reference now to  FIG. 7 , a second rod section  100  comprising a second pin end  102  and second box end  104  is shown. The second pin end  102  of the second rod section  100  is shown entering the box end  26  of the rod section  14 . Biased to the locked position, the engagement point  58  ( FIG. 3 ) extends from the pin end  24 ,  102  of the rod section  14 ,  100 . Thus, the engagement point  58  will contact the opening ( FIG. 4 ) of box end  26  until rotated into position such that the engagement point  58  of pin end  102  is within lock engagement stop  49  ( FIG. 4 ) of the box end  26 . 
         [0030]    With reference now to  FIG. 8 , the rod sections  14 ,  100  of the present invention are oriented such that the box end alignment groove  40  of the first rod section  14  is aligned with a pin end alignment groove  106  of the second rod section  100 . The pin end  102  of the second rod section  100  is advanced without rotation into the box end  26  of the first rod section  14 . In this orientation, the engagement points  58  of the lock engagement mechanism  50  of rod section  100  contact an inner wall of the box end  26 . 
         [0031]    With reference now to  FIG. 9 , the second rod section  100  is rotated less than a full turn such that the box end alignment groove  40  is aligned with a lock symbol  109 . Preferably, the second rod section  100  is rotated approximately a quarter turn. This alignment indicates the grooved section  42  ( FIG. 3 ) of the box end  26  of the first rod section  14  has mated with the grooved portion  28  of the second rod section  100  and the rotation stop  32  has met the shoulder  48  ( FIGS. 2 and 3 ). Further, the lock engagement mechanism  50  ( FIG. 3 ) in the locked position will have its engagement points  58  ( FIG. 3 ) within the lock engagement stop ( FIG. 4 ) of rod section  14 , rotationally locking the rod sections  14 ,  100  in both a counterclockwise and clockwise direction. 
         [0032]    With reference now to  FIG. 10 , a key  110  is shown. The key  110  comprises an internal surface  112  and castellations  114 . The internal surface  112  corresponds to the rod removal drive  56  ( FIG. 3 ) of the lock engagement mechanism  50  ( FIG. 3 ). The castellations  114  allow for increased surface contact for ease of rotating the key  110 . An opening  116  may be provided to allow for high torque rotation of the key  110 . 
         [0033]    With reference to  FIG. 11 , insertion of the key  110  into the box end  104  of a rod section  100  and rotation of the key  110  causes the lock engagement mechanism  50  ( FIG. 3 ) to go from the locked position to the unlocked position as described with reference to  FIG. 5B  above. This allows the lock engagement points  58  to retract from the lock engagement stop  49  ( FIG. 4 ) located in the box end of pipe section  14 , allowing for breakout of sections of the rod string  12 . 
         [0034]    Various modifications can be made in the design and operation of the present invention without departing from the spirit thereof. Thus, while the principal preferred construction and modes of operation of the invention have been explained in what is now considered to represent its best embodiments, which have been illustrated and described, it should be understood that the invention may be practiced otherwise than as specifically illustrated and described.