The invention relates to rotary boring and, in particular to an improved joint for connecting two rotatable components of a boring system.
The present invention is directed to a pipe joint for use in rotary boring operations. The pipe joint comprises a first member, a second member, and a ground engaging member. The first member has a non-circular exterior surface and a threaded socket. The second member comprises a threaded end portion for mating engagement with the threaded socket and a non-circular exterior surface portion corresponding to the non-circular exterior surface of the first member. The ground engaging member has a non-circular internal surface and an outer surface for enlarging a borehole. The non-circular internal surface corresponds to the non-circular exterior surface of both the first member and the second member for slidably mounting the ground engaging member on the non-circular exterior surfaces of the first member and the second member when the threaded socket of the first member is engaged with the threaded end portion of the second member and to transmit torque between the first member and the second member. Alignable holes are formed in the ground engaging member and the second member for receiving a fastener to secure the ground engaging member to the second member.
The present invention is further directed to a rotary boring system comprising a rotary machine, a drill string, and a downhole tool. The drill string has a first end and a second end. The first end is operatively connected to the rotary drive machine to drive rotation of the drill string. The downhole tool comprises a first member, a second member, and a ground-engaging member. The first member is connected to the second end of the drill string and comprises a non-circular exterior surface and a connector socket. The second member comprises a connector portion for mating engagement with the connector socket and a non-circular exterior surface portion corresponding to the non-circular exterior surface of the first member. The ground engaging member has a non-circular internal surface and an outer surface for enlarging a borehole. The non-circular internal surface corresponds to the non-circular surface of both the first member and the second member for slidably mounting the ground engaging member on the non-circular surfaces of the first member and the second member when the connector end portion is engaged with the connector socket and to transmit torque between the first member and the second member. The downhole tool further comprises alignable holes in the ground engaging member and the second member for receiving a fastener to secure the ground engaging member to the second member.
Further still, the present invention is directed to a method for making boreholes using a boring machine having a rotary drive system capable of rotating and axially advancing or retracting a downhole tool attached to a drill string. The method comprises the steps of connecting a first end of an elongate first member to the drill string, wherein the first member comprises a first end and a second end, the second end comprising a socket and a non-circular outer surface. A ground engaging member having a correspondingly non-circular internal surface is slid over the second end of the first member. A second member is engaged to the socket of the first member and oriented such that a non-circular surface formed thereon fits within the non-circular internal surface of the ground engaging member to pass rotation of the drill string and the first member to the ground engaging member and the second member by means of the non-circular surfaces.
Still yet, the present invention is directed to an adapter for connecting a pair of drilling components. The adapter comprises a first member, a second member, and a ground engaging member. The first member has a non-circular exterior surface and threaded socket. The second member has a threaded end portion and a non-circular exterior surface rearward of the threaded end portion. The threaded end portion is engagable with the threaded socket of the first member. The ground engaging member has a non-circular profile on an inner surface thereof whereby the ground engaging member is slidably mounted on the non-circular exterior profiles of the first and second members when such profiles are brought into alignment by rotation of one member relative to the other in a manner effective to pass torque from one member to the other by means of the non-circular profiles.
The present invention is further directed to a pipe joint for use in rotary boring operations. The pipe joint comprises a first member, a second member, and a ground engaging member. The first member has a non-circular exterior surface and a first connector. The second member comprises a second connector for mating engagement with the first connector and a non-circular exterior surface portion corresponding to the non-circular exterior surface of the first member. The ground engaging member has a non-circular internal surface and an outer surface for enlarging a borehole. The non-circular internal surface corresponds to the non-circular exterior surface of both the first member and the second member for slidably mounting the ground engaging member on the non-circular exterior surfaces of the first member and the second member when the first connector is engaged with the second connector and to transmit torque between the first member and the second member.
Rotary boring systems for making holes through soil are well known. The boring system generally includes drill string comprising a series of drill pipes joined end to end. The drill string is rotated by a rotary drive machine and pushed or pulled through the ground by means of a powerful hydraulic device such as a hydraulic cylinder or a gear rack actuated by a hydraulic motor. A boring head for boring in soil, rock or both is disposed at the end of the drill string and may include an ejection nozzle for water or other drilling fluid to assist in boring. In other applications, tools such as pipe bursters, impactors, slitters and pullers are used to slit, burst and replace existing underground pipelines. Reamers may be used along or in combination with any of the aforementioned tools to upsize a borehole.
In most horizontal boring operations a pilot bore is drilled between a starting point and an end point. Once the boring tool reaches the end point, whether the surface of the ground or a pit, the boring tool is removed and a backreamer may be attached to the drill string. The backreamer is used to upsize the borehole to meet or slightly exceed the outer diameter of the product pipe towed into the bore during pullback. Easy attachment of the product pipe to a backreamer assembly in a small access pit is disclosed in U.S. Patent application number 2002/0112890, the contents of which are incorporated herein by reference. If attempting to make a switch out in a pit, the swap will require enlargement of the access pit lengthwise to accommodate the length of the backreamer and its connection components. Ideally, the operator would like the change of tools to occur rapidly and be easily accomplished without the need to dig a large access pit. The present invention allows an operator to change tools at the downhole end of a drill string in a small access pit.
Turning now to the figures and specifically to
The ground engaging member 16 shown in
Turning now to
The second member 14 comprises a second connector, depicted as a threaded end portion 46 for mating engagement with the first connector 42. When threads are used, as shown in
As illustrated, the second connector 42 is a tapered threaded end portion disposed between a central collar 48 and a front face 50 of the second member 14. The second member 14 also comprises a hole 52 that is alignable with a corresponding hole 32 in ground engaging member 16. Alignable holes 52 and 32 allow the second member to be locked in position relative to the ground engaging member 16 with fastener 33. A first stop member 53 is formed on the second member 14 to abut the ground engaging member 16 and defines a first boundary of the central collar 48. A second stop member 62 defines a second boundary of the central collar 48 and abuts a front face 64 of the first member 12.
An O-ring 54 may be positioned adjacent front face 50 of the second member 14 and against a wall 56 of the first member 12 in a groove 58. The O-ring 54 protects the socket 42, wall 56 and threads 46 from ingress of abrasive materials that would exacerbate wear during operations. The O-ring 54 also prevents the egress of drilling fluid as it passes from passage 44 into passage 60 formed in the second member 14. A radial passage 65 is formed in the second member 14 allow fluid to flow from the internal passage 60 into the cross-sectional clearance area 68 (
In operation, joint 10 is assembled by sliding ground engaging member 16 over the first member 12. Threaded end portion 46 of second member 14 is then screwed into threaded socket 42 and tightened to the desired level. After threaded end portion 46 of second member 14 has been tightened to the desired degree in threaded socket 42, the alignment of exterior surfaces 48 and 40 is checked. If the profiles of the non-circular exterior surfaces 48 and 40 are not aligned ground engaging member 16 will not slide over second member 14, consequently, the second member is unscrewed or backed off until the profiles of exterior surfaces 48 and 40 are aligned. The ground engaging member 16 is then slid along first member 12 and over non-circular exterior surface 48 of the second member 14. In the event that the profiles of exterior surfaces 48 and 40 are not aligned when second member 14 is tightened to the desired level, the degree to which the second member will have to be backed off or loosened to align the profiles depends upon the selected profile. For example, in the case of an octagonal profile, the angle between the centers of each flat surface is 360/8 or 45°. Thus, in case of octagonal profile, the maximum number of degrees that second member 14 may have to be backed off after tightening to align the octagonal profiles of exterior surfaces 48 and 40 is the rotational difference between successive surfaces, or 45°.
After the ground engaging member has been positioned over the second member 14, a retaining bolt or screw 33 is passed through hole 32 in the ground engaging member and engaged with bolt hole 52 in the second member, locking the ground engaging member onto the second member. Shoulder 53 prevents the ground engaging member 16 from sliding rearward as ground engagement forces are applied. Bolts 33 retain ground engaging member 16 should the normal direction of the drill string be reversed. Preferably, one or more of alignable holes 52 and 32 and bolt 33 are provided with NPT (National Pipe Thread) threads which provide improved retention and greater shear area than convention straight threads.
Continuing in
Turning now to
The ground engaging member 16 comprises a frustoconical backreaming member having a plurality of helical grooves 28 and carbide teeth 26 for enlarging the borehole. The ground engaging member 16 comprises a non-circular internal surface that corresponds to the non-circular exterior surfaces of the first member and the second member for slidably mounting the ground engaging member on the non-circular surfaces of the first member and the second member when the connector end portion 46 is engaged with the connector socket 42. Such connection allows for the transmission of torque between the first member and the second member.
Alignable holes 32 and 52 are formed in the ground engaging member 16 and the second member 14 receive fasteners 33 to secure the ground engaging member 16 to the second member 14. One skilled in the art will appreciate that alignable holes may alternatively be formed in the first member to secure the ground engaging member to the first member instead of the second member or in addition to the holes formed in the second member.
Turning now to
In the method for making boreholes in accordance with the present invention, a boring machine having a rotary drive system capable of rotating and axially advancing or retracting a downhole tool attached to a drill string is used. The method comprises connecting the first end 18 of the first member 12 to the drill string. The first member 12 may be connected to the drill string by rotating the first member in a first direction to thread the first member 12 to the drill string. The ground engaging member 16 is slid over the second end 18 of the first member 12 so that the non-circular exterior surface 40 of the first member is positioned with the interior non-circular surface 66 of the ground engaging member. The non-circular surfaces 40 and 66 may comprise a geometric profile. For purposes of illustration only, an octagonal profile will be described. The octagonal profiles of the first member and the ground engaging member 16 are aligned before sliding the ground engaging member over the second end 20 of the first member.
The second member 14 is engaged to the socket 42 of the first member 12 and the second member is oriented, by rotation, such that the non-circular surface 66 of the second member fits within the ground engaging member 16 to pass rotation of the drill string and the first member to the ground engaging member and the second member. The second member 14 may comprise a threaded end portion 46 and the socket 42 may comprise corresponding threads. The method comprises threading the threaded end portion into the socket until the external non-circular surface of the second member is adjacent to the ground engaging member. The second member may then be rotated slightly to align the external non-circular surface 48 with the internal non-circular surface of the ground engaging member. The ground engaging member 16 is then moved axially to substantially cover the external non-circular surface of the second member. The holes 32 and 52 are aligned and the fastener 33 is inserted into the holes to fasten the second member 14 to the ground engaging member 16.
As will be appreciated, the joint of the invention is applicable to a variety of applications wherein tools used in horizontal directional drilling are connected to a drill string. Joints in accordance with the invention are particularly useful in coupling drill bits, sonde housings, reamers, back reamers, starter rods, impactors and similar drilling tools to a drill string or together in a manner that facilitates rapid replacement of such components while simultaneously providing joints and couplings with an increased usable lifetime and enhanced reliability.
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, as herein illustrated and described, it should be understood that the invention may be practiced otherwise than as specifically illustrated and described.
This application claims priority to U.S. Provisional Patent Application No. 61/365,961, filed Jul. 20, 2010, the contents of which are incorporated fully herein by reference.
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Number | Date | Country | |
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20120018221 A1 | Jan 2012 | US |
Number | Date | Country | |
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61365961 | Jul 2010 | US |