Dual member pipe joint for a dual member drill string

Abstract

A dual-member pipe joint having an outer member and an inner member which is disposed coaxially within the outer member. Both the outer member and the inner member have a pin end and a box end. The pin end of the outer member is threadable to the box end of another outer member. The pin end of the inner member is geometrically shaped. The box end of the inner member forms a recess which conforms to the geometric shape of the pin end of the inner member. The box end of the inner member nonthreadably receives the pin end of another inner member in “slip-fit” connection. “Slip-fit” means the pin end of the inner member slides into the box end of a like inner member and forms a connection that is capable of transmitting torque. The advantage of this dual-member pipe joint is that both the inner and outer members of a pipe joint may be connected to a drill string in a single action with just one connection. This dual-member pipe joint reduces boring time as compared to boring with conventional dual-member pipe joints, in which both the inner and outer members are threadably connected and thus require two pipe connections. The dual-member pipe joint is usable as a system of pipe, and as part of a boring machine.

We claim:  
     
       1. A pipe joint for use in drill strings in rotary boring applications comprising: 
       an elongate, hollow outer member having an inner surface and an outer surface and having a pin end and a box end, wherein the pin end and the box end are correspondingly threaded; and  
       an elongate inner member having a geometrically-shaped pin end and a box end forming a geometrically-shaped recess corresponding to the shape of the pin end of the inner member, the pin end being slideably receivable in connector-free, torque-transmitting engagement with the box end of a similarly formed inner member;  
       wherein the inner member is arranged generally coaxially within the outer member forming an annular space between the inner member and the inner surface of the outer member.  
     
     
       2. The pipe of  claim 1  wherein the box end of the inner member is positioned within the box end of the outer member and the inner surface of the outer member forms an annular shoulder at the box end of the outer member and the box end of the inner member forms a shoulder, the shoulder of the inner member being sized to restrict axial movement of the inner member within the outer member in the direction of the pin ends of the inner and outer members. 
     
     
       3. The pipe of  claim 2  wherein the pin end of the inner member extends a distance beyond the pin end of the outer member and a radially projecting annular stop member is disposed near the pin end of the inner member beyond the pin end of the outer member. 
     
     
       4. The pipe of  claim 3  wherein the radially projecting annular stop member comprises a collar and a set screw. 
     
     
       5. The pipe of  claim 1  wherein the outer surface of the outer member defines a circumferential groove near the pin end of the outer member. 
     
     
       6. The pipe of  claim 1  wherein the inner member comprises a solid rod. 
     
     
       7. A system of pipe joints comprising: 
       a plurality of pipe joints, each pipe joint comprising:  
       an elongate, hollow outer member having an inner surface and an outer surface and having a pin end and a box end, wherein the pin end and the box end are correspondingly threaded; and  
       an elongate inner member having a geometrically-shaped pin end and a box end forming a geometrically-shaped recess corresponding to the shape of the pin end of the inner member, the pin end being slideably receivable in connector-free, torque-transmitting engagement with the box end of a similarly formed inner member;  
       wherein the inner member is arranged generally coaxially within the outer member forming an annular space between the inner member and the inner surface of the outer member;  
       wherein the pin end of the inner member of each pipe joint is connectable to the box end of the inner member of another one of the plurality of pipe joints; and  
       wherein the pin end of the outer member of each pipe joint is connectable to the box end of the outer member of another one of the plurality of pipe joints so that the outer members of the plurality of pipe joints, when connected, form a passageway extending the length of the system of pipe joints.  
     
     
       8. The system of pipe joints of  claim 7  wherein the box end of the inner member is positioned within the box end of the outer member, the inner surface of the outer member forms an annular shoulder at the box end of the outer member and the box end of the inner member forms a shoulder, the shoulder of the inner member being sized to restrict axial movement of the inner member within the outer member in the direction of the pin ends of the inner and outer members. 
     
     
       9. The system of pipe joints of  claim 8  wherein the pin end of the inner member extends a distance beyond the pin end of the outer member and a radially projecting annular stop member is disposed near the pin end of the inner member beyond the pin end of the outer member. 
     
     
       10. The system of pipe joints of  claim 9  wherein the radially projecting annular stop member comprises a collar and a set screw. 
     
     
       11. The system of pipe joints of  claim 7  wherein the outer surface of the outer member defines a circumferential groove near the pin end of the outer member. 
     
     
       12. The system of pipe joints of  claim 7  wherein the inner member comprises a solid rod. 
     
     
       13. A horizontal boring machine comprising: 
       a frame;  
       a rotary machine supported on the frame;  
       a drill string having a first end and a second end, the first end being operatively connectable to the rotary machine to drive the rotation of the drill string, the drill string comprising:  
       a plurality of pipe joints, each pipe joint comprising:  
       an elongate, hollow outer member having an inner surface and an outer surface and having a pin end and a box end, wherein the pin end and the box end are correspondingly threaded; and  
       an elongate inner member having a geometrically-shaped pin end and a box end forming a geometrically-shaped recess corresponding to the shape of the pin end of the inner member, the pin end being slideably receivable in connector-free, torque-transmitting engagement with the box end of a similarly formed inner member;  
       wherein the inner member is arranged generally coaxially within the outer member forming an annular space between the inner member and the inner surface of the outer member;  
       wherein the pin end of the inner member of each pipe joint is connectable to the box end of the inner member of another one of the plurality of pipe joints; and  
       wherein the pin end of the outer member of each pipe joint is connectable to the box end of the outer member of another one of the plurality of pipe joints so that the outer members of the plurality of pipe joints, when connected, form a passageway extending the length of the system of pipe joints; and  
       a directional boring head attached to the second end of the drill string.  
     
     
       14. The horizontal boring machine of  claim 13  wherein the rotary machine further comprises: 
       a carriage assembly supported on the frame;  
       an inner member drive group for driving the plurality of inner members comprising the drill string, the inner member drive group being supported on the carriage assembly and comprising an inner member drive motor, an inner spindle and a torque-transmitting member for transmitting torque from the inner member drive motor to the inner spindle, wherein the inner spindle is connectable to the inner member at the first end of the drill string;  
       an outer member drive group for driving the plurality of outer members comprising the drill string, the outer member drive group being supported on the carriage assembly and comprising an outer member drive motor, an outer spindle and a torque-transmitting member for transmitting torque from the outer member drive motor to the outer spindle, wherein the outer spindle is connectable to the outer member at the first end of the drill string; and  
       a biasing assembly supported on the carriage and adapted to urge substantially simultaneous, slideable, connector-free, torque-transmitting engagement of the inner member of a pipe joint loaded on the boring machine with the rotary machine and with the inner member at the first end of the drill string.  
     
     
       15. The boring machine of  claim 13  wherein the box end of the inner member is positioned within the box end of the outer member, the inner surface of the outer member forms an annular shoulder at the box end of the outer member and the box end of the inner member forms a shoulder, the shoulder of the inner member being sized to restrict axial movement of the inner member within the outer member in the direction of the pin ends of the inner and outer members. 
     
     
       16. The boring machine of  claim 15  wherein the pin end of the inner member extends a distance beyond the pin end of the outer member and a radially projecting annular stop member is disposed near the pin end of the inner member beyond the pin end of the outer member. 
     
     
       17. The boring machine of  claim 16  wherein the radially projecting annular stop member comprises a collar and a set screw. 
     
     
       18. The boring machine of  claim 13  wherein the outer surface of the outer member defines a circumferential groove near the pin end of the outer member. 
     
     
       19. The boring machine of  claim 13  wherein the inner member comprises a solid rod. 
     
     
       20. A horizontal boring machine, comprising: 
       a frame;  
       a drill string having a first end and a second end, the drill string comprising  
       a plurality of pipe joints, each pipe joint comprising:  
       an elongate, hollow outer member having an inner surface and an outer surface and having a pin end and a box end, wherein the pin end and the box end are correspondingly threaded; and  
       an elongate inner member having a geometrically-shaped pin end and a box end forming a geometrically-shaped recess corresponding to the shape of the pin end of the inner member, the pin end being slideably receivable in connector-free torque-transmitting engagement with the box end of a similarly formed inner member;  
       wherein the inner member is arranged generally coaxially within the outer member forming an annular space between the inner member and the inner surface of the outer member;  
       wherein the pin end of the inner member of each pipe joint is connectable to the box end of the inner member of another one of the plurality of pipe joints; and  
       wherein the pin end of the outer member of each pipe joint is connectable to the box end of the outer member of another one of the plurality of pipe joints so that the outer members of the plurality of pipe joints, when connected, form a passageway extending the length of the system of pipe joints;  
       a directional boring head attached to the second end of the drill string; and  
       a rotary machine supported on the frame, the rotary machine being operatively connectable to the first end of the drill string for driving the rotation of the drill string, the rotary machine comprising:  
       a carriage assembly supported on the frame;  
       an inner member drive group for driving the plurality of inner members comprising the drill string, the inner member drive group being supported on the carriage assembly and comprising an inner member drive motor, an inner spindle and a torque-transmitting member for transmitting torque from the inner member drive motor to the inner spindle, wherein the inner spindle is connectable to the inner member at the first end of the drill string;  
       an outer member drive group for driving the plurality of outer members comprising the drill string, the outer member drive group being supported on the carriage assembly and comprising an outer member drive motor, an outer spindle and a torque-transmitting member for transmitting torque from the outer member drive motor to the outer spindle, wherein the outer spindle is connectable to the outer member at the first end of the drill string; and  
       a biasing assembly supported on the carriage and adapted to urge substantially simultaneous, slideable, connector-free, torque-transmitting engagement of the inner member of a pipe joint loaded on the boring machine with the rotary machine and with the inner member at the first end of the drill string.  
     
     
       21. The boring machine of  claim 20  wherein the box end of the inner member is positioned within the box end of the outer member, the inner surface of the outer member forms an annular shoulder at the box end of the outer member and the box end of the inner member forms a shoulder, the shoulder of the inner member being sized to restrict axial movement of the inner member within the outer member in the direction of the pin ends of the inner and outer members. 
     
     
       22. The boring machine of  claim 21  wherein the pin end of the inner member extends a distance beyond the pin end of the outer member and a radially projecting annular stop member is disposed near the pin end of the inner member beyond the pin end of the outer member. 
     
     
       23. The boring machine of  claim 22  wherein the radially projecting annular stop member comprises a collar and a set screw. 
     
     
       24. The boring machine of  claim 20  wherein the outer surface of the outer member defines a circumferential groove near the pin end of the outer member. 
     
     
       25. The boring machine of  claim 20  wherein the inner member comprises a solid rod. 
     
     
       26. A method for making directional boreholes using a boring machine having a rotary machine capable of simultaneously rotating and axially advancing a directional boring head attached to a drill string comprising a plurality of connectable pipe joints, each pipe joint having an inner member disposed generally coaxially within an outer member, each outer member being connectable to another one of the outer members comprising the plurality of pipe joints and each inner member being slideably receivable in connector-free, torque-transmitting engagement with the rotary machine and with another one of the inner members comprising the plurality of pipe joints, the method comprising the steps of: 
       making one connection per additional pipe joint loaded on the boring machine for connection with the drill string by simultaneously axially advancing the rotary machine and transmitting torque from the rotary machine to the additional pipe joint, whereby the outer member of the additional pipe joint substantially simultaneously connects with the rotary machine and with the outer member at the first end of the drill string while the inner member of the additional pipe joint substantially simultaneously, slideably, nonrotatably connects in connector-free torque-transmitting engagement with the rotary machine and with the inner member at the end of the drill string; and  
       axially advancing and rotating the directional boring head to make a borehole.  
     
     
       27. The method of  claim 26  further comprising the step of: 
       breaking pipe joint connections by reversing the method of making pipe joint connections.  
     
     
       28. A horizontal boring machine, comprising: 
       a drill string having a first end and a second end, the drill string comprising a plurality of pipe joints, each pipe joint comprising:  
       an elongate, hollow outer member having an inner surface and an outer surface and having a pin end and a box end, wherein the pin end and the box end are correspondingly threaded; and  
       an elongate inner member having a geometrically-shaped pin end and a box end forming a geometrically-shaped recess corresponding to the shape of the pin end of the inner member, the pin end being slideably receivable in connector-free, torque-transmitting engagement with the box end of a similarly formed inner member;  
       wherein the inner member is arranged generally coaxially within the outer member forming an annular space between the inner member and the inner surface of the outer member;  
       wherein the pin end of the inner member of each pipe joint is connectable to the box end of the inner member of another one of the plurality of pipe joints; and  
       wherein the pin end of the outer member of each pipe joint is connectable to the box end of the outer member of another one of the plurality of pipe joints so that the outer members of the plurality of pipe joints, when connected, form a passageway extending the length of the system of pipe joints.  
     
     
       29. The horizontal boring machine of  claim 28  wherein the box end of the inner member is positioned within the box end of the outer member, the inner surface of the outer member forms an annular shoulder at the box end of the outer member and the box end of the inner member forms a shoulder, the shoulder of the inner member being sized to restrict axial movement of the inner member within the outer member in the direction of the pin ends of the inner and outer members. 
     
     
       30. The horizontal boring machine of  claim 29  wherein the pin end of the inner member extends a distance beyond the pin end of the outer member and a radially projecting annular stop member is disposed near the pin end of the inner member beyond the pin end of the outer member. 
     
     
       31. The horizontal boring machine of  claim 30  wherein the radially projecting annular stop member comprises a collar and a set screw. 
     
     
       32. The horizontal boring machine of  claim 28  wherein the outer surface of the outer member defines a circumferential groove near the pin end of the outer member. 
     
     
       33. The horizontal boring machine of  claim 28  wherein the inner member comprises a solid rod. 
     
     
       34. The horizontal boring machine of  claim 29  wherein the inner member comprises a pipe, so that when the inner members comprising the plurality of pipe joints are connected, a second passageway extending the length of the system of pipe joints is formed. 
     
     
       35. A method for making directional boreholes using a boring machine having a drive system capable of simultaneously rotating and axially advancing a directional boring head comprising a drill bit and attached to a drill string comprising a plurality of connectable pipe joints, each pipe having an inner member disposed generally coaxially within an outer member, the method comprising the steps of: 
       
         connecting the inner member and the outer member of a pipe joint to the inner member and outer member of a like pipe joint substantially simultaneously;  
       
       
         axially advancing the directional boring head; and  
       
       
         driving rotation of the drill bit with the inner members of the drill string. 
       
     
     
       36. The method of  claim 35 , wherein a steering mechanism is supported on the outer member near the boring head, the method further comprising the step of: 
       
         controlling the direction of the borehole by selectively rotating the outer members of the drill string to position the steering mechanism. 
       
     
     
       37. The method of  claim 36  further comprising the step of: 
       
         changing the borehole direction by orienting the outer drill string member substantially in the desired rotational position for an interval of axial advance. 
       
     
     
       38. The method of  claim 35  further comprising the step of: 
       
         simultaneously rotating and axially advancing a directional boring head attached to a drill string using dual rotary drives. 
       
     
     
       39. A pipe joint for use in drill strings in rotary boring applications comprising: 
       
         an elongate, hollow outer member having an inner surface and an outer surface, a central body portion and having a first end and a second end, wherein the first end and the second end are each connectable to adjacent similarly formed outer members; and  
       
         an elongate inner member having a first end and a second end, the first end being receivable in non - threaded, torque - transmitting engagement with the second end of a similarly formed inner member while the first end of the outer member connects substantially simultaneously with the second end of a similarly formed outer member;    
       
         wherein the inner member is arranged generally coaxially within the outer member forming an annular space between the inner member and the inner surface of the outer member. 
       
     
     
       40. The pipe joint of  claim 39  wherein the first end and second end of the outer member are correspondingly threaded for connection to adjacent similarly formed outer members. 
     
     
       41. The pipe joint of  claim 39  wherein the first end and second end of the outer member are correspondingly a pin end and a box end. 
     
     
       42. The pipe joint of  claim 39  wherein the first end and second end of the inner member are correspondingly a pin end and a box end. 
     
     
       43. The pipe joint of  claim 39  wherein the first end of the inner member extends a distance beyond the first end of the outer member and a radially projecting annular stop member is disposed near the first end of the inner member beyond the first end of the outer member. 
     
     
       44. The pipe joint of  claim 39  wherein the outer surface of the outer member defines a circumferential groove near the first end of the outer member. 
     
     
       45. The pipe joint of  claim 39  wherein the inner member comprises a solid rod. 
     
     
       46. The pipe joint of  claim 39  wherein the outer surface of the outer member defines a means for positioning the pipe joint on the boring machine near the first end of the outer member. 
     
     
       47. A system of pipe joints comprising: 
       
         a plurality of pipe joints, each pipe joint comprising:  
       
       
         an elongate, tubular outer member having an inner surface and an outer surface, a central body portion, and having a first end and a second end, wherein the first end and the second end are each connectable to adjacent similarly formed outer members; and  
       
         an elongate inner member having a first end and a second end, the first end being receivable in non - threaded, torque - transmitting engagement with the second end of a similarly formed inner member;    
       
         wherein the inner member is arranged generally coaxially within the outer member forming an annular space between the inner member and the inner surface of the outer member;  
       
       
         wherein the first end of the inner member and the first end of the outuer member of each pipe joint are substantially simultaneously connectable to the second end of the inner member and the second end of the outer member of another one of the plurality of pipe joints; and  
       
       
         wherein the first end of the outer member of each pipe joint is connectable to the second end of the outer member of another one of the plurality of pipe joints so that the outer members of the plurality of pipe joints, when connected, form a passageway extending the length of the system of pipe joints. 
       
     
     
       48. The system of pipe joints of  claim 47  wherein the first end and second end of the outer member are correspondingly threaded for connection to adjacent similarly formed outer member. 
     
     
       49. The system of pipe joints of  claim 47  wherein the first end and second end of the outer member are correspondingly a pin end and a box end. 
     
     
       50. The system of pipe joints of  claim 47  wherein the first end and second end of the inner member are correspondingly a pin end and a box end. 
     
     
       51. The system of pipe joints of  claim 47  wherein the first end of the inner member extends a distance beyond the first end of the outer member and a radially projecting annular stop member is disposed near the first end of the inner member beyond the first end of the outer member. 
     
     
       52. The system of pipe joints of  claim 47  wherein the outer surface of the outer member defines a circumferential groove near the first end of the outer member. 
     
     
       53. The system of pipe joints of  claim 47  wherein the inner member comprises a solid rod. 
     
     
       54. The system of pipe joints of  claim 47  wherein the outer surface of the outer member defines a means for positioning the pipe joint on the boring machine near the first end of the outer member. 
     
     
       55. A horizontal boring machine, comprising: 
       
         a drill string having a first end and a second end, the drill string comprising a plurality of pipe joints, each pipe joint comprising:  
       
       
         an elongate, tubular outer member having an inner surface and an outer surface and having a first end and a second end, wherein the first end and the second end are each connectable to similarly formed outer members; and  
       
         an elongate inner member having a first end and a second end, the first end being receivable in non - threaded, torque - transmitting engagement with the second end of a similarly formed inner member;    
       
         wherein the inner member is arranged generally coaxially within the outer member forming an annular space between the inner member and the inner surface of the outer member;  
       
       
         wherein the first end of the inner member and the first end of the outer member of each pipe joint are substantially simultaneously connectable to the second end of the inner member and the second end of the outer member of another one of the plurality of pipe joints; and  
       
       
         wherein the first end of the outer member of each pipe joint is connectable to the second end of the outer member of another one of the plurality of pipe joints so that the outer members of the plurality of pipe joints, when connected, form a passageway extending the length of the system of pipe joints. 
       
     
     
       56. The horizontal boring machine of  claim 55  further comprising: 
       
         a frame; and  
       
       
         a rotary drive supported on the frame, the rotary drive being operatively connectable to the first end of the drill string for driving the rotation of the drill string. 
       
     
     
       57. The horizontal boring machine of  claim 56  wherein the rotary drive comprises a biasing assembly to urge substantially simultaneous, non- threaded, torque - transmitting engagement of the inner member of a pipe joint loaded on the boring machine with the rotary drive and with the inner member at the first end of the drill string.   
     
     
       58. The horizontal boring machine of  claim 55  further comprising a directional boring head attached to the second end of the drill string. 
     
     
       59. The horizontal boring machine of  claim 55  wherein the first end and second end of the outer member are correspondingly threaded for connection to adjacent similarly formed outer members. 
     
     
       60. The horizontal boring machine of  claim 55  wherein the first end and second end of the outer member are correspondingly a pin end and a box end. 
     
     
       61. The horizontal boring machine of  claim 55  wherein the first end and second end of the inner member are correspondingly a pin end and a box end. 
     
     
       62. The horizontal boring machine of  claim 55  wherein the first end of the inner member extends a distance beyond the first end of the outer member and a radially projecting annular stop member is disposed near the first end of the inner member beyond the first end of the outer member. 
     
     
       63. The horizontal boring machine of  claim 55  wherein the outer surface of the outer member defines a circumferential groove near the first end of the outer member. 
     
     
       64. The horizontal boring machine of  claim 55  wherein the inner member comprises a solid rod. 
     
     
       65. The horizontal boring machine of  claim 55  wherein the outer surface of the outer member defines a means for positioning the pipe joint on the boring machine near the first end of the outer member.