Patent Publication Number: US-11384601-B2

Title: Hole opener for horizontal directional drilling

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 62/812,316, filed Mar. 1, 2019, the entire contents of which are hereby incorporated by reference. 
    
    
     BACKGROUND 
     The present invention relates to a hole opener particularly suited for use with a horizontal directional drilling rig. 
     SUMMARY 
     In one aspect, the invention provides a hole opener for use with a horizontal directional drilling rig, the hole opener comprising a shaft, a key, a first blade, and a second blade. The shaft includes a front end, a rear end, and a longitudinal axis that extends through the front end and the rear end, the shaft configured for rotation about the longitudinal axis by the horizontal directional drilling rig. The key is coupled to the shaft for rotation with the shaft. The first blade is removably coupled to the key, and is spaced a first radial distance from the longitudinal axis and spaced a first longitudinal distance from the front end. The second blade is removably coupled to the key and is spaced a second radial distance from the longitudinal axis that is greater than the first radial distance. The second blade is spaced a second longitudinal distance from the front end that is greater than the first longitudinal distance. 
     Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a hole opener according to one embodiment of the invention. 
         FIG. 2  is a cross-sectional view of a shaft of the hole opener of  FIG. 1  taken along line  2 - 2  of  FIG. 3 . 
         FIG. 3  illustrates a tail exploded from the shaft of the hole opener of  FIG. 1 . 
         FIG. 4  is a perspective view of the tails assembled on the shaft of the hole opener of  FIG. 1 . 
         FIG. 5  is a cross-sectional view of the assembled tails and shaft of  FIG. 4  taken along line  5 - 5  of  FIG. 3 . 
         FIG. 6  is a side view of a key of the hole opener of  FIG. 1 . 
         FIG. 7  illustrates the key of  FIG. 6  assembled on the shaft of the hole opener of  FIG. 1  with the tails. 
         FIG. 8  is a cross-sectional view of  FIG. 7  taken along line  8 - 8  of  FIG. 7 . 
         FIG. 9  illustrates blades of the hole opener of  FIG. 1  exploded from the key. 
         FIG. 10  is a cross-sectional view of the hole opener of  FIG. 1  taken along line  10 - 10  of  FIG. 8  illustrating the blades assembled on the key and showing multiple keys. 
         FIG. 11  is a cross-sectional view of  FIG. 9  of the hole opener of  FIG. 1  taken along line  11 - 11  of  FIG. 8  illustrating fluid apertures extending from the shaft. 
         FIG. 12  illustrates a gauge ring of the hole opener of  FIG. 1  exploded from the hole opener. 
         FIG. 13  illustrates a guide ring of the hole opener of  FIG. 1  exploded from the hole opener. 
         FIG. 14  is a cross-sectional view of  FIG. 1  illustrating flow tubes of the hole opener of  FIG. 1  exploded from the hole opener. 
         FIG. 15  is a side view of the hole opener of  FIG. 1 . 
         FIG. 16  is a cross-sectional view of  FIG. 15  taken along line  16 - 16  of  FIG. 15 . 
         FIG. 17  illustrates a horizontal drilling rig configured for use with the hole opener of  FIG. 1 . 
         FIG. 18  illustrates side view of a hole opener according to another embodiment. 
         FIG. 19  illustrates a top view of the hole opener of  FIG. 18 . 
     
    
    
     Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. 
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a hole opener or reamer  10 . The hole opener  10  is particularly suited for use with a horizontal directional drilling rig  12  ( FIG. 17 ) for creating underground bores. The underground bores are used for utilities, including water lines, sewer lines, gas lines, electrical conduits, communication lines or conduits, direct buried electrical wires, and the like. Although the hole opener  10  is particularly suited for use with a horizontal directional drilling rig, in other embodiments, the hole opener  10  can be configured for use with other types of drilling rigs. 
     The illustrated hole opener  10  includes a shaft  14 , tails  16 , keys  18 , blades  20 , and a gauge ring  22 . As will be discussed in more detail below, the hole opener  10  is configured so that the blades  20  can be replaced when the blades  20  are worn or when different types of blades  20  are desired based on the drilling application (e.g., type of earth material that is being drilled). 
     Referring to  FIG. 10 , the shaft  14  includes as first end  24 , a second end  26 , and a longitudinal axis  28  that extends centrally through the ends  24 ,  26 . An aperture  30  is formed into each of the first end  24  and the second end  26 . The apertures  30  are configured (e.g., threaded connection, pin connection, etc.) to mate with extension rods or drive rods  32  ( FIG. 17 ) to connect the hole opener  10  to a drilling rig, such as the horizontal directional drilling rig  12 . Rotation of the extension rods  32  by the drilling rig rotates the shaft  14  about axis  28 , which rotates the blades  20  to perform the underground boring or drilling operation. In addition to rotating the hole opener  10  about the axis  28 , the drilling rig  12  also moves or advances the hole opener  10  in the direction of arrow  31  of  FIG. 10  to perform the drilling operation. 
     With reference to  FIGS. 10 and 11 , the illustrated shaft  14  includes a bore  36  that extends from the first end  24  to the second end  26  such that the shaft  14  is generally hollow. Fluid apertures  38  extend from the bore  36  to outside the shaft  14  between the tails  16  and the blades and the keys  18 . The fluid apertures  38  allow a drilling fluid (e.g., bentonite clay) to pass through the rods  32  ( FIG. 17 ), through the bore  36  and then through the fluid apertures  38  to remove cuttings from between the keys  18  and the tails  16 . The drilling fluid also removes cuttings from the bore  36  and stabilizes the bore  36  to inhibit collapse of the bore  36 . 
     Referring to  FIGS. 2 and 3 , the shaft  14  further includes slots  40  that extend along and parallel to the longitudinal axis  28  of the shaft  14 . The slots  40  receive the tails  16  and the keys  18  to locate or positions the tails  16  and keys  18  on the shaft  14 . In one embodiment, the tails  16  and the keys  18  are welded to the shaft  14  after being positioned in the slots  40 . The slots  40  provide additional stability and torque transfer capability from the shaft  14  to the tails  16  and to the keys  18  that support the blades  20 . In the illustrated embodiment, the slots  40  are machined into the shaft  14 . Also, in the illustrated embodiment, the shaft  14  includes six slots  40  evenly spaced around the circumference of the shaft  14 . Therefore, the hole opener  10  includes six tails  16  and six keys  18 . In other embodiments, the shaft  14  my include fewer than six slots  40  or more than six slots  40  and therefore, fewer than or more than six tails  16  and keys  18 . As shown in  FIG. 3 , the fluid apertures  38  are between the slots  40  so that the tails  16  and keys  18  do not inhibit the drilling fluid from exiting the shaft  14 . 
     Referring to  FIG. 2 , each slot  40  is off center or not symmetrical about the longitudinal axis  28  as explained below. The off center slot  40  better positions blades  20  for cutting and drilling the bore. The slot  40  includes a base or bottom surface  42 . The bottom surface  42  is flat and the bottom surface  42  is within a plane  44  as shown in  FIG. 2 . The tail  16  and key  18  abut the bottom surface  42 . Therefore, the orientation of the bottom surface  42  determines the orientation or direction the tails  16  and keys  18  extend from the shaft  14 . The bottom surface  42  includes a first end  46  and a second end  48 . The plane  44  also extends through the ends  46 ,  48 . A center  50  of the slot  40  is located midway between ends  46 ,  48  along the plane  44 . The slot  40  is off center in that a radially extending line  52  that extends from the longitudinal axis  28  through the center  50  is not perpendicular to the plane  44 . Alternatively stated, a line  54  perpendicular to the plane  44  does not pass through the center of the shaft  14  or longitudinal axis  28 . The line  54  is at an angle  56  relative to the radially line  52  through the center  50  of the slot  40 . In one embodiment, the angle  56  is in a range from about 2 degrees to about 25 degrees. In another embodiment, the angle  56  is in a range from about 2 degrees to about 15 degrees and in a range from about 2 degrees to about 10 degrees in yet another embodiment. In yet other embodiments, the angle  56  is in a range from about 5 degrees to about 15 degrees. 
     Referring to  FIG. 10 , a tail  16  and a key  18  are received in each of the slots  40 . The key  18  is adjacent to and in front of the tail  16 . In other words, a key distance  18   a  between the key  18  and the first end  24  is greater than a tail distance  16   a  between the tail  16  and the first end  24 . Referring to  FIG. 5 , the off center configuration of the slots  40 , discussed above, results in a central plane  58  of the tail  16  and key  18  that does not pass through the center of the shaft  14 . Rather, the plane  58  is offset from the rotation axis  28  ( FIG. 2 ) of the shaft  14 . 
     Referring to  FIGS. 9 and 10 , the blades  20  are coupled to the keys  18 . In the illustrated embodiment, each key  18  includes three blades  20 . In other embodiments, the keys  18  may include fewer than three or more than three blades  20 . The keys  18  includes recesses  60   a ,  60   b , and  60   c  in a stepped configuration that each receive a blade  20 . The first recess  60   a  is spaced a distance  62   a  from the longitudinal axis  28  as illustrated in  FIG. 10  and also positioned a distance  63   a  from the end  24 , which is the front end  24  when the hole opener  10  travels in the direction of arrow  31  of  FIG. 10 . The second recess  60   b  is spaced a distance  62   b  from the axis  28  that is greater than the distance  62   a  and the second recess  60   b  is between the first recess  60   a  and the third recess  60   c  along the axis  28 . In other words, a distance  63   b  from the recess  60   b  to the first end  24  is between the distance  63   a  and a distance  63   c  between the first end  24  and the recess  60   a . The third recesses  60   c  is spaced a distance  62   c  from the axis  28  that is greater than the distance  62   b  and the third recesses  60   c  is closer to the back end  26  of the shaft  14  than the other recesses  62   a  and  62   b . In other words, the distance  63   c  is greater than both the distance  63   a  and the distance  63   b.    
     Referring to  FIG. 10 , the recesses  60   a - 60   c  are in the stepped configuration as described above to properly position the blades  20  received in the recesses  60   a - 60   c  for drilling. That is, the blades  20  are exposed continually along a radial distance  76  from the axis  28 . Therefore, as the hole opener  10  rotates about the axis  28  and moves in the direction of arrow  31  the hole opener enlarges the bore to a radius  80 . The hole opener  10  is configured to enlarge or open a bore having approximately a minimum starting radius  78  and enlarge the bore to a radius  80 . 
     The blades  20  include cutters  66  fixed to a base  68 . The cutters  66  can include any suitable cutter including, polycrystalline diamond compact cutters, tungsten carbide cutters, diamond impregnated tungsten carbine cutters, cubic boron nitride cutters, and the like. In one embodiment, the base  68  is steel or a similar material to the key  18 . The blades  20  further include a pin bore  70  and a pin  72  that is received in the pin bore  70 . The pin  72  is received in a corresponding bore  74  (i.e., a key bore  74 ) of the key  18  to couple the blades  20  to the key  18 . The pin  72  and bores  70 ,  72  allow a user to quickly and easily properly position the blades  20  when the blades  20  are replaced. In one embodiment, the base  68  is also welded to the key  18 . The blades  20  are removably coupled to the key  18  by the pin and welding arrangement described above so that the blades  20  can be removed and replaced. The user may remove or replace the blades  20  when the cutters  66  are worn or replaced when a different cutter type is desired depending on the drilling operation. For example, if the drilling operation is in a hard earth material, the blades  20  (i.e., a first blade and a second blade) may be replaced with a cutter  66  suited for hard earth material (i.e., a third blade and a fourth blade). If the next drilling operation is in a soft earth material, the blades  20  are replaced with a cutter  66  suited for soft earth material. Therefore, the user can relatively easily replace the blades  20  by removing the weld, removing the blades  20 , and replacing the blades  20  with different blades and welding the new blades  20  to the key  18 . 
     With continued reference to  FIG. 10 , cutters  66 ′ engage bores  70 ′ of the key  18 . The bores  70 ′ extend radially inwardly from an edge of the key  18  towards the longitudinal axis  28  of the shaft  14 . When the cutters  66 ′ engage the bores  70 ′, the cutters  66 ′ extend radially outwardly from within the bores  70 ′ to the radius defining the enlarged size of the bore created by the hole opener  10 .  FIG. 1  illustrates the cutters  66 ′ extending from the bores  70 ′. Longitudinally (i.e., in a direction of the longitudinal axis  28  of the shaft  14 ), the blades  20  are closer to the first end  24  of the shaft  14  when compared to the cutters  66 ′ and the bores  70 ′. 
     With reference to  FIG. 12 , the gauge ring  22  coupled to the hole opener  10  over the tails  16  from a position adjacent the second end  26  of the shaft  14  to a position radially outward of the tails  16  relative to the shaft  14 . The gauge ring  22  abuts an edge of the keys  18  closest to the recess  60   c . With reference to  FIG. 15 , the gauge ring  22  is positioned longitudinally (in a direction of the longitudinal axis  28 ) behind the key  18  and radially outward of the tail  16 . In other words, a gauge ring distance  22   a  between the gauge ring  22  and the first end  24  of the shaft  14  is greater than a longitudinal distance  63   c  between a blade  20  mounted in the recess  60   c  and the first end  24 . An outer surface of the gauge ring  22  is spaced from the longitudinal axis  28  of the shaft  14  an amount of the radius  80  which defines the enlarged size of the bore created by the hole opener  10 . The gauge ring  22  applies pressure radially outwardly from the longitudinal axis  28  of the shaft  14  to the edges of the bore created by the hole opener  10 . The gauge ring  22  ensures that the radius  80  cut by the blades  20  is retained after the hole opener  10  is no longer in contact with the bore. 
     With reference to  FIG. 13 , a guide ring  82  is coupled to the hole opener  10  over the keys  18  from a position adjacent the first end  24  of the shaft  14  to a position radially outward of the keys  18  relative to the shaft  14 . In other words, the guide ring  82  is positioned longitudinally (in a direction of the longitudinal axis  28 ) in front of the blades  20  and radially outward of the keys  18 . With reference to  FIGS. 10 and 15 , the guide ring  82  is positioned a guide ring distance  82   a  away from the first end  24 . The guide ring distance is less than the key distance  18   a . The guide ring  82  abuts a guide ring projection  84  of the keys  18 . 
     A wear bar  86  including a plurality of cutters  88  is coupled to an angled portion  90  of the key  18 . During operation, cutters  88  mounted on the wear bar  86  engage a hole or bore in the ground and center the hole opener  10  on the hole or bore in the ground. In one embodiment, the wear bar  86  is steel and is welded onto the key  18  and the cutters  88  are tungsten carbide and are brazed onto the wear bar  86 . The wear bar  86  is replaceable from the angled portion  90  through welding and the cutters  88  are individually replaceable from the wear bar  86  through brazing. Other attachment methods between the cutters  88  and the wear bar  86  and the wear bar  86  and the keys  18  may be used. Other materials of the cutters  88  are possible, such as those listed above for the cutters  66 . The guide ring  82  includes cutouts  92  permitting cuttings from the cutters  88  to be passed radially outwardly relative to the longitudinal axis  28  from within the minimum starting radius  78 . The cuttings are removed from between the key  18  and a second key  18  mounted on the shaft  14 . The cutouts  92  are triangularly shaped in the illustrated embodiment. 
     With reference to  FIGS. 14-16 , flow tubes  94  are coupled to the shaft  14  and the key  18  to adjust an exit location of the fluid from the fluid apertures  38 . The flow tubes  94  define cylindrical passageways that permit the flow of fluid there through. The flow tubes  94  extend radially outwardly from the shaft  14  and are positioned rotationally ahead of an adjacent key  18 . The flow tubes  94  reposition the exit location of the fluid apertures  38  from adjacent the shaft  14  (without the flow tubes  94 ) to a position adjacent each blade  20 . Fluid is more efficiently applied to the cutters  66  when the flow tubes  94  are attached. 
     Referring to  FIG. 17 , and in a cutting operation of the hole opener  10 , extension rods  32  are moved by the crane  104  onto the drill rig  12 . The extension rods  32  are translated through a hole  102  to be reamed to the opposite end (not shown) of the hole  102 , with additional extension rods  32  being added as the extension rods  32  are translated through the hole  102 . The extension rods  32  are attached to the hole opener  10 . An operator in the control trailer  108  supplies power through the power unit  116  to the drill rig  12  to rotate the hole opener  10 , and translate the hole opener  10  along a cutting path of the hole  102 . In some embodiments, the cutting path of the hole  102  is directed towards the drill rig  12 , and the hole opener  10  is pulled through the hole  102 . In this embodiment, the crane  104  lifts extension rods  32  from the drill rig  12  as they are translated out of the hole  102 . Alternatively, the cutting path of the hole  102  can be directed away from the drill rig  12 , and the hole opener  10  is pushed through the hole  102  by the drill rig  12 . In this alternative embodiment, the crane  104  lifts extension rods  32  to apply them to the drill rig  12  as they are needed to further translate the hole opener  10  through the hole  102 . During drilling, cuttings from within the hole  102  created by the hole opener  10  are excavated into the mud rig  112  for removal from the reamed hole  102 . 
     Referring to  FIGS. 18 and 19 , an alternate hole opener  120  includes a shaft  122  having a first end  124  and a second end  126 . A longitudinal axis  128  of the shaft  122  extends through the ends  124 ,  126 . A blade  130  extends radially outwardly from the shaft  122 . Shearing cutters  132  are mounted on a top surface  134  of the blade  130 . Gouging cutters  136  are mounted to a side surface  138  of the blade  130 . Each gouging cutter  136  defines a gouging cutter axis  140  extending from a tip  142  of the gouging cutter  136  towards the side surface  138  where the gouging cutter  136  is mounted to the blade  130 . During a cutting operation of the hole opener  120 , the shaft  122  is rotated counter-clockwise about the longitudinal axis  128  when viewed from  FIG. 19 . As such, gouging cutters  136  mounted on a blade  130  contact the material being cut prior to the shearing cutters  132  mounted on the same blade  130 . The gouging cutter  136  is fixedly mounted to the blade  130  to inhibit rotation of the gouging cutter  136  about the gouging cutter axis  140  during a cutting operation. Optionally, the gouging cutters  136  and the shearing cutters  132  may be removably coupled to the blade  130  for replacement of worn cutters  132 ,  136 . The gouging cutters  136  and shearing cutters  132  may consist of the same materials listed above for the cutters  66 .