Abstract:
A breakout wrench for use with a rock drill string includes a frame adapted for mounting to a rock drill feed guide structure, and a sub-frame rotatably connected to the frame about a drill string longitudinal axis. The sub-frame supports a pair of jaw members adapted for radial movement towards and away from one another and to releasably engage a first section of a drill string. The breakout wrench also includes a clamping member supported by the rock drill feed guide structure. The clamping member is adapted to releasably engage a second section of the drill string spaced axially from the first section.

Description:
TECHNICAL FIELD 
       [0001]    The invention relates to a breakout wrench and centralizer system for use in rock drilling operations. 
       BACKGROUND 
       [0002]    A rock drill uses a drill string made up of drill rods and/or drill tubes, added to or taken away from the drill string, to achieve the required drilling depth for blast holes. The rock drill may use impact waves transmitted down the drill string along with rotation to the drill bit to fracture the formation being drilled into. During the drill string impact and rotation, the drill string joints may tighten and make them difficult to break loose from one other. 
         [0003]    When the desired drilled hole depth is achieved, the drill rods and/or drill tubes are removed one at a time for storage. A typical method of breaking loose the joints between the rods or tubes is to stop drilling entirely while the drill string is at the bottom of the hole, reduce the feed pressure against the drill string, and start rattling. Rattling the drill rods and/or drill tubes is when the drill string rests against the bottom of the drilled hole and percussion impacts from the rock drill are used to impart compressive and tensile impact waves to loosen the drill string joints. 
         [0004]    Some drill string components may be more difficult to break loose the joints than others due to a variety of reasons. Often an experienced driller can tell by the change in sound while rattling if the drill string joints have been broken loose. However, often only some of the joints are broken loose in a string, while others remain tightened, and the driller needs to use other means and/or methods to break the drill string joints loose. 
       SUMMARY 
       [0005]    An embodiment of the invention includes a breakout wrench system for use with a rock drill string. The breakout wrench has a frame adapted for mounting to a rock drill feed guide structure, and a sub-frame rotatably connected to the frame about a drill string longitudinal axis. The sub-frame supports a pair of jaw members adapted for radial movement towards and away from one another and to releasably engage a first section of a drill string. The breakout wrench also has a clamping member supported by the rock drill feed guide structure, with the clamping member adapted to releasably engage a second section of the drill string spaced axially from the first section. 
         [0006]    Another embodiment includes a breakout wrench for use with a rock drill string. The breakout wrench has a centralizer with a frame adapted for mounting to a rock drill feed guide structure, and a sub-frame rotatably connected to the frame about a drill string longitudinal axis. The sub-frame supports a first pair of jaw members adapted to engage and rotate a first section of a drill string using at least a pair of actuators. The breakout wrench also has a clamping assembly supported by the rock drill feed guide structure. The clamping assembly has a second pair of jaw members being actuated by at least a first actuator and a third pair of jaw members being actuated by at least a second actuator. The second pair of jaw members and third pair of jaw members are spaced axially apart from one another. The at least a first actuator and at least a second actuator are connected to a flow controller for moving the second pair of jaw members and the third pair of jaw members. The second pair of jaw members and the third pair of jaw members are adapted to releasably engage a second section of the drill string spaced axially from the first section. 
         [0007]    A further embodiment includes a breakout wrench for use with a drill string. The breakout wrench has a first clamping assembly rotatably supported by a rock drill structure about a drill string longitudinal axis. The clamping assembly is adapted to secure and rotate a first section of the drill string during a breakout operation and adapted to centralize the drill string during a drilling operation. The breakout wrench also has a second clamping assembly supported by the rock drill structure, where the clamping assembly is adapted to secure a second section of the drill string during a breakout operation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a side view of a male-male drill rod with a round body and a coupling; 
           [0009]      FIG. 2  is a side view of a male-female drill rod with a round body and a coupling; 
           [0010]      FIG. 3  is a side view of a male end of a drill rod with a hexagonal body; 
           [0011]      FIG. 4  is a side view of a male-female drill rod with a tubular body; 
           [0012]      FIG. 5  is a schematic of a rock drill using drill rods or tubes in a drill string; 
           [0013]      FIG. 6  is a perspective view of a centralizer according to the prior art; 
           [0014]      FIG. 7  is a perspective view of a rock drill, centralizer, and rod changer according to the prior art; 
           [0015]      FIG. 8  is a partial perspective view a breakout wrench system and rod changer according to an embodiment of the present invention; 
           [0016]      FIG. 9  is a perspective view of a breakout wrench according to another embodiment of the present invention; 
           [0017]      FIG. 10  is a plan view of the breakout wrench of  FIG. 9  in a clamped position; 
           [0018]      FIG. 11  is a plan view of the breakout wrench of  FIG. 9  in a clamped and rotated position; 
           [0019]      FIG. 12  is a sectional view of the breakout wrench of  FIG. 9  in an unclamped and unrotated configuration; 
           [0020]      FIG. 13  is a sectional view of the breakout wrench of  FIG. 9  in a clamped configuration; 
           [0021]      FIG. 14  is a sectional view of the breakout wrench of  FIG. 9  in a clamped and rotated configuration; and 
           [0022]      FIG. 15  is a sectional view of the breakout wrench of  FIG. 9  in an unclamped and rotated position. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for the claims and/or as a representative basis for teaching one skilled in the art to variously employ the present invention. 
         [0024]    A rock drill uses a drill string made up of drill rods and/or drill tubes, added to or taken away from the drill string, to achieve the required drilling depth for blast holes. Drill rods are commonly designed in different forms.  FIG. 1  shows an example of a drill rod  100  with two male ends  102 . In one embodiment the drill rod  100  is a tubular heavy wall rod with male threads at each end  102 . A coupling  104  is used to connect adjacent drill rods  100  into a drill string. The coupling  104  has two female threaded ends  106 , which are sized to receive the male ends  102  of the drill rod  100 . 
         [0025]      FIG. 2  shows another embodiment of a drill rod  110 , which has a male end  112  and a female end  114  on a tubular heavy wall rod. The drill rods  110  are joined to one another by connecting the male end  112  of a rod  110  into a female end  114  of an adjacent rod  110 .  FIGS. 1-2  depict drill rods  100 ,  112  with round bodies  118 .  FIG. 3  depicts an alternative embodiment of a drill rod  120  having a hexagonal body  122  and a male end  124 . Various other rods and couplings are also contemplated according to economics and efficiencies. 
         [0026]    Additionally, the rod  130  may have a tubular body  132 , as shown in  FIG. 4 , with a thinner wall section. In the embodiment shown, the tube rod  130  has a male end  134  and a female end  136 , allowing the rod  130  to be joined to adjacent rods in a drill string. When the tube rods  130  are connected using the male and female ends  134 ,  136  of adjacent rods  130 , the shoulder region  138  of a male end  134  may have contact with a shoulder region  140  of a female end  136 , which may improve transmission of an impact wave from one rod  130  to another and down a drill string during a drilling or rattling operation. 
         [0027]    A schematic of a rock drill  150  is shown in  FIG. 5 . A drill unit  152  has a drill feed guide  154 . The drill feed guide supports a rock drill  156 , which can travel linearly along the feed guide  154 . The drill string  158  is connected to the rock drill  156  for drilling operations. The drill string  158  extends down into the drilled hole  160 , and is made up of drill rods  162  or drill tubes such as those described previously in  FIGS. 1-4 . In this embodiment, several drill rods  160  are present and are connected using drill string connections  164 . The drill string  158  passes through a centralizer  166 , which is also attached to the drill feed guide  154 . A drill bit  168  is connected to one of the drill rods  162 . The rock drill  150  may use impact waves when necessary to aid in the drilling process and fracture formations underground. During the drill string  158  impact and rotation, the drill string joints  164  may tighten and make them difficult to break loose from one other. 
         [0028]    A typical method of breaking loose the joints  164  between the rods  162  or tubes is to stop drilling entirely while the drill string  158  is at the bottom of the hole  160 , reduce the feed pressure against the drill string  158 , and start what is often called “rattling”. Rattling the drill rods  162  and/or drill tubes is when the drill string  158  rests against the bottom of the hole  160  and percussion impacts from the rock drill  156  are used to impart compressive and tensile impact waves to loosen the drill string joints  164 . 
         [0029]    The centralizer  166  may be partially closed around the drill rod  162  and/or drill tube to provide centered support and centered guidance for the drill string  158  during drilling. A prior art centralizer  170  is shown in  FIG. 6 , and has two centralizer arms  172  and a pair of jaw members  174  to engage the drill rod  162  or to engage a connection  164 . 
         [0030]    To loosen a drill rod coupling  164 , as shown in  FIG. 5 , the drill rod  162  and/or the drill tube is clamped in the centralizer  166  and the rock drill  156  rotates the drill rod  162  and/or drill tube to unscrew the joint  164 . Some drill string  158  components may be more difficult to break loose the joints  164  than others due to a variety of reasons. 
         [0031]    To remove the drill rods  162  and/or drill tubes from the hole  160  that has been drilled, the drill rods  162  and/or drill tubes are raised by the rock drill  156  until the bottom of the first drill rod  162  and/or drill tube is visibly just above the centralizer  166 . The centralizer  166  clamps on the outside diameter of the coupling  164  or the outside diameter of the female portion of the drill rod  162  and/or drill tube. The rock drill  156  then reverses to unscrew the drill rod  162  above the centralizer  166  for storage. A similar reverse process is used for adding drill rods  162  to a drill string  162  during a drilling operation. 
         [0032]      FIG. 7  depicts a typical drill feed guide  200  and rock drill  202  for use with a drill unit. The rock drill  202  travels linearly along the feed guide  200  along tracks  204 . The travel and position of the rock drill  202  is controlled using a motor  206  and chain  208 , or other linear motion device. A prior art centralizer  210  is connected to the feed guide  200  and does not translate with the rock drill  202 . 
         [0033]    When the desired drilled hole  160  depth is achieved, the drill rods  162  and/or drill tubes are removed one at a time, using a method as described previously with the centralizer  210  clamping onto a drill rod connection and the rock drill  202  reversing to unscrew the connection. Rattling may also be used as necessary to loosen the connections. The loosened and removed drill rod  162  is stored in a rod changer device  212 . Dependant of the design of the rod changer  212 , the drill rod is held with grippers  214  of varying designs to position it into rod changer  212  slots or pockets. In one embodiment, the grippers  214  are hydraulically actuated for both clamping onto the drill rod  162  and translating the drill rod to the changer  212 . The grippers  214  are connected to a flow controller  215  to control the movement. The flow controller may be connected to an electronic control module, which also provides for a user interface. Once the drill rod  162  and/or drill tube is stored in the rod changer  212 , the rock drill  202  is then fed down the feed guide  200  and screwed into the drill rod and/or drill tube held in the centralizer  210  and the process repeats. The drill rod and/or drill tube removal procedure is used until the last rod is unattached from the rock drill  202 . 
         [0034]    Referring back to  FIG. 5 , in the event one or more drill rod and/or drill tube joints  164  had not broken loose from rattling, the driller would clamp onto the outside diameter of the coupling  164  attached to the drill rod  162  with the centralizer  166  and use the rock drill  156  to rattle the coupling  164  in the centralizer  166 . Rattling the drill string using the centralizer  166  is used since it takes less time than adding rods  162  back to the drill string  158  and rattling the drill string  158  against the bottom of the hole  160  again. This procedure of rattling in the centralizer  166  can cause damage to the drill string  158  components and centralizer  166  components. 
         [0035]      FIG. 8  depicts an embodiment of a powered breakout wrench system  300  which acts both as a centralizer and as a breakout wrench to aid in loosening a drill rod and/or drill tube connection. The wrench system  300  is shown attached to a feed guide  200  in place of the centralizer  210  of  FIG. 7 . The rod changer device  212  and one of the two grippers  214  are also shown in  FIG. 8 . In another embodiment, the system may have only one gripper  214 . The drill string may still be rattled loose at the bottom of the hole if desired, but the breakout wrench system  300  provides a means of holding the drill rod and/or drill tube while rotating the drill string to aid in breaking of drill string joints, for example when one or more have not rattled loose while in the drilled hole. The rod grippers  214  secure the drill rod and/or drill tube to prevent twisting when the breakout wrench  300  is rotated to aid in breaking loose tightened joints. Once the drill rod and/or drill tube joints have been broken loose and the rock drill  202  has unscrewed from the drill string, the grippers  214  move the drill rod into the rod changer  212 . The rod changer  212  may be a single changer or a carousel changer. 
         [0036]    Each gripper  214  has a pair of jaw members  216 , multiple jaw members, or other clamping mechanism for clamping onto and retaining a drill rod or drill tube, and it may lie along the drill string longitudinal axis when the grippers  214  are rotated to that position. The grippers  214  may be used to secure a second section or drill rod in a drill string, while the breakout wrench  300  rotates the first section to perform a breakout operation and loosen the joint or coupling between the first and second drill rods. 
         [0037]    The jaw members  216  are actuated by an actuator  218 , such as a hydraulic or pneumatic cylinder. Any number of actuators  218  are contemplated for use by a rod gripper  214 . An additional actuator (not shown) may be used in one embodiment to rotate the rod gripper  214  for placing the drill rod into the changer  212 . The actuator  218  is connected to a flow controller  215 , which controls the movement of the jaw members  216  and of the rod gripper  214 . The flow controller  215  may be connected to actuators  215  of more than one rod gripper  214  (as in  FIG. 7 ) in order to move the jaws  216  or each gripper  214  in unison with one another. This allows for even clamping by multiple grippers  214  of the drill rod, which minimizes uneven loading or torquing of the drill rod. Alternatively, the flow controller  215  may contain a feedback mechanism such that the jaw members  216  are controlled to move and contact the drill rod simultaneously and apply even and equal loading across the multiple rod grippers  214 . This may be useful if the drill rod or tube does not lie exactly along a longitudinal axis. 
         [0038]      FIG. 9  depicts the breakout wrench system  300  in detail for use with the rod gripper  214  of  FIGS. 7 and 8 . A frame  302  is used to connect the wrench system  300  to the feed guide  200 . The frame  302  supports a sub-frame  304 . A bearing assembly  306 , bushing, or the like is used to connect the sub-frame  304  to the frame  302 , and allow the sub-frame  304  to rotate about a longitudinal axis  308  of the drill string. The sub-frame  304  also supports a clamping assembly  310 , such as a pair of jaw members, multiple jaw members, or other as is known in the art such that the clamping assembly  310  may partially close around the drill string to centralize it, or may clamp onto the drill string to secure it for a breakout operation. The clamping assembly  310  may also use a spring mechanism or other self-centralizing mechanism as is known in the art to centralize the drill string during a drilling operation. Alternatively, the clamping assembly  310  may be controlled to centralize the drill string using the jaw members. A dustpot  322  is also shown in  FIG. 9  and is supported by the frame  302  and is spaced apart from the first clamping assembly  310 . 
         [0039]    A pair of actuators  312  is used with the clamping assembly  310 , although any number of actuators  312  may be used. The actuators  312  may be hydraulically powered, pneumatic, or the like, and may be double acting. As shown in  FIG. 9 , the actuators  312  are hydraulic and may have ports  314  for the fluid connections. The actuators  312  are mounted in line with the motion of the jaw members of the clamping assembly  310 , although other orientations are contemplated. A flow controller  315  is connected to the actuators  312  in order to control the movement of the clamping assembly  310  to evenly grip to centralize a drill rod. The flow controller  315  may be integrated into flow controller  215  in one embodiment. 
         [0040]    A third actuator  316  and linking arm  318  are shown connecting the frame  302  and the sub-frame  304 , and are used for rotational motion of the clamping assembly  310 . The actuator  316  has ports  320  for hydraulic connections of a double acting actuator; however, a pneumatic or other actuator is also contemplated. The actuator  316  is pivotally connected to the frame  302  and the sub-frame  304 . When the actuator  316  extends, it exerts a force on the linking arm  318 , which in turn moves and rotates the sub-frame  304  and clamping assembly  310 . When the actuator  316  retracts, the linking arm  318  rotates the sub-frame  304  in the reverse direction. The actuator  316  may also be connected and controlled using the flow controller  315 . 
         [0041]      FIG. 10  shows a plan view of the breakout wrench  300  clamped onto a drill rod  326  and/or drill tube.  FIG. 11  shows a top plan view of the breakout wrench  300  clamped onto a drill rod  326  and/or drill tube and rotated to break the joint loose. The pair of actuators  312  is shown in line with one another. The actuator  316  is extended in  FIG. 11  to provide the rotation of the clamping assembly  310  by moving the linking arm  318  connected to the sub-frame  304  supporting the clamping assembly  310 . The grippers  214  (See  FIGS. 7-8 ) are also in a clamped or secured position about another section of the drill string, which is not rotating. The clamping assembly  310  rotates the first drill rod  326  through up to ninety degrees, while the second drill rod is held in place by the grippers  214 , and the breakout operation is completed. 
         [0042]      FIGS. 12-15  depict section views of the breakout wrench  300  through its various states of operation. In  FIG. 12 , the clamping assembly  310  is shown in an un-clamped, un-rotated configuration. The pair of jaw members  328  is retracted and spaced apart from the first section  326  of the drill string. The actuators  312  are shown in line with the jaw members  328 , and in a refracted position. Of course, other orientations of the actuators  312  are contemplated. The linking arm  318  is connected to the sub-frame  304  and connected to the third actuator  316 , which is also in a retracted position. The third actuator  316  connects to the frame  302 . The grippers  214  may be either unclamped from another section of the drill string, or clamped onto another section of the drill string at this time. 
         [0043]      FIG. 13  shows a section view of the breakout wrench  300  in a clamped, un-rotated configuration. The actuators  312  have extended the jaw members  328  towards one another such that the first section  326  of the drill string is secured. At this time, the grippers  214  (see  FIGS. 7-8 ) may also be clamped about a second section of the drill string. In another mode (not shown), the pair of jaw members  328  are partially actuated to a position between that of  FIGS. 12 and 13 , and controlled to centralize a drill string during a drilling operation. The flow controller  315  controls the position of the jaw members  328  with respect to the longitudinal axis  308  and also potentially with respect to one another. Springs or other self-centralizing mechanisms (not shown) may also be used to bias the jaw members  328  into a position to centralize the drill string. 
         [0044]      FIG. 14  shows a section view of the breakout wrench  300  as it would look in a clamped and rotated configuration. The pair of jaw members  328  is in a clamped position securing the first section  326  of the drill string. The third actuator  316  extends to provide the rotation of the clamping assembly  310  about the drill string longitudinal axis  308  by moving the linking arm  318  connected to the sub-frame  304  supporting the clamping assembly  310 . The clamping assembly  310  rotates the first drill rod  326  through up to ninety degrees, while the second drill rod is held in place by the rod grippers  214 , and the breakout operation is completed. 
         [0045]      FIG. 15  shows a sectioned view of the breakout wrench  300  as it would look in an un-clamped and rotated configuration. The third actuator  316  remains extended, while the pair of actuators  312  have retracted the jaw members  328  from contact with the drill string  326 . 
         [0046]    The clamping assembly  310  then returns back to the configuration shown in  FIG. 12  of an un-clamped, un-rotated configuration with the pair of jaw members  328  spaced apart from the first section  326  of the drill string. At this point, the joint will have been loosened such that adjoining drill string rods or sections can be separated from one another for storage. The rod grippers  214  may still secure the second drill rod for placement into the changer  212 , while the rock drill is secured into the first section  326  in the drill string. 
         [0047]    Referring now to  FIGS. 7 and 8 , during a breakout operation of the rock drill string, the rock drill  202  travels up the feed guide  204 . The rod grippers  214  move in alongside the drill string and the jaws  216  clamp onto a first section or drill rod of the string in a controlled manner. The centralizer  300  also clamps onto a second section or drill rod of the string. These two clamping operations may happen simultaneously, or in no particular order. Once both the grippers  214  and centralizer  300  have clamped onto the drill string, the centralizer  300  rotates the second section of the drill string with respect to the first section, which is held in place by the grippers  214 . 
         [0048]    Once the joint between the first and second sections of the drill string has been broken loose, the rod grippers  214  can release the first section of the drill string while the rock drill  202  unscrews it from the second string, which is held in place by the centralizer  300 . Once the sections are separated, the rod grippers can clamp onto the first section, while the rock drill  202  disconnects from the first section, and then the first section can be moved to the rod changer  212 . The centralizer  300  may unrotate at this point, while still clamping onto the drill string. 
         [0049]    The rock drill  202  then travels down the feed guide  200  and connects with the second section held by the centralizer  300  and the remaining portion of the drill string. The centralizer may release the drill string, and un-rotate at this phase. The rock drill  202  and drill string then travel up the feed guide  200  and the process repeats for another drill rod removal. 
         [0050]    This process may be repeated as many times as necessary to loosen any tightened drill string connections as the drill string is raised by the rock drill from the drilled hole. 
         [0051]    While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.