US-12618289-B2 - Apparatus for capturing axial force on an inner drive member

US12618289B2US 12618289 B2US12618289 B2US 12618289B2US-12618289-B2

Abstract

A spindle with a mechanism for transferring axial force from an inner drive assembly to an outer drive assembly. The spindle's inner drive shaft is connected to an inner member of a dual-rod pipe by a drive rod having a sliding sleeve. The sleeve is fixed rotationally with the drive shaft, but not axially. When axial force drives the drive rod toward the drive member of the spindle, the sleeve contacts a stop member which is paired to the outer drive assembly. The stop member may be a pair of dowel pins. Axial force is thereby transferred from the inner member to the outer member, allowing such forces to be absorbed by the outer member's larger drive components.

Inventors

Max A. Metcalf

Assignees

THE CHARLES MACHINE WORKS, INC.

Dates

Publication Date: 20260505
Application Date: 20250203

Claims (17)

1 . A method of operating a drilling system comprising a dual-member drill string, the method comprising: rotating an inner drive shaft about a longitudinal axis to apply torque to an inner member of the dual-member drill string through a hollow sleeve, wherein the hollow sleeve is slidably engaged with the inner drive shaft such that the hollow sleeve is axially movable relative to the inner drive shaft while maintaining torque transmission; simultaneously, rotating an outer drive shaft independently of the inner drive shaft to apply torque to an outer member of the dual-member drill string; biasing the hollow sleeve away from the inner drive shaft using a compression spring; and transmitting axial force from the hollow sleeve to a stop member, wherein the stop member is configured to transfer axial force to the outer drive shaft.
2 . The method of claim 1 in which the stop member comprises at least one dowel pin.
3 . The method of claim 1 in which the hollow sleeve and inner drive shaft comprise complementary interlocking splines.
4 . The method of claim 1 , wherein the outer drive shaft is rotationally driven by an outer output gear coupled to a motor.
5 . The method of claim 1 , further comprising the step of compressing the spring as the hollow sleeve moves axially toward the inner drive shaft.
6 . The method of claim 1 , wherein the hollow sleeve terminates in a shoulder, the shoulder configured to contact the stop member to transfer axial force.
7 . The method of claim 1 , further comprising the step of circulating drilling fluid through a central passage of the inner drive shaft.
8 . A method of preventing damage to a gearbox in a dual-member drilling system, the gearbox comprising an inner drive shaft and an outer drive shaft, the method comprising: rotating the inner drive shaft about a longitudinal axis to apply torque to an inner member of a dual-member pipe segment through a hollow sleeve, wherein the hollow sleeve is slidably engaged with the inner drive shaft to allow axial movement relative to the inner drive shaft while maintaining torque transmission; simultaneously, rotating the outer drive shaft independently of the inner drive shaft to apply torque to an outer member of the dual-member pipe segment; biasing the hollow sleeve away from the gearbox with a spring disposed between the inner drive shaft and the hollow sleeve; permitting axial movement of the hollow sleeve toward the gearbox in response to an axial force applied to the inner member of the pipe segment; and engaging a stop member with the hollow sleeve when the hollow sleeve reaches a limit of axial movement toward the gearbox; wherein engagement of the stop member transfers axial force to the outer drive shaft.
9 . The method of claim 8 , wherein the stop member comprises a pair of parallel dowel pins.
10 . The method of claim 9 in which the pair of parallel dowel pins are transferred to the longitudinal axis.
11 . The method of claim 8 further comprising attaching the hollow sleeve to an inner drive rod, wherein the inner drive rod comprises a collar for connection to the inner member of the dual-member pipe segment.
12 . The method of claim 11 in which the hollow sleeve is connected to the inner drive rod by a circumferential weld.
13 . The method of claim 8 , wherein the hollow sleeve and inner drive shaft comprise complementary interlocking splines.
14 . The method of claim 8 , wherein the spring is a compression spring, and further comprising the step of compressing the spring in response to axial movement of the hollow sleeve toward the gearbox.
15 . The method of claim 8 , wherein the outer drive shaft is rotationally driven by an outer output gear coupled to a motor.
16 . The method of claim 8 wherein the dual-member pipe segment is characterized as a first dual-member pipe segment and further comprising: with the inner drive shaft and the outer drive shaft, rotating the first dual-member pipe segment such that the first dual-member pipe segment connects to a second dual-member pipe segment.
17 . The method of claim 8 wherein the dual-member pipe segment is characterized as a first dual-member pipe segment and further comprising: with the inner drive shaft and the outer drive shaft, rotating the first dual-member drive segment such that the first dual-member pipe segment is disconnected from a second dual-member pipe segment.

Description

SUMMARY The present invention is directed to an apparatus. The apparatus comprises an inner member, an outer member, an inner drive shaft, a hollow sleeve, and at least one pin. The inner member is disposed along a longitudinal axis. The outer member is at least partially surrounding the inner member and disposed about the longitudinal axis. The inner drive shaft is coupled to a motor. The hollow sleeve is joined to the inner member in sliding, torque-transmitting engagement with the inner drive shaft. The at least one pin is disposed through the outer member and transverse to the longitudinal axis. The at least one pin is configured to transmit axial force from the hollow sleeve to the outer member. The present invention is also directed to a spindle. The spindle comprises an inner drive rod apparatus, a hollow outer member, and at least one stop member. The inner drive apparatus is disposed about a longitudinal axis and comprises a drive shaft, an inner drive rod, and a hollow sleeve. The inner drive rod is configured for connection to an inner member of a dual-member drive string. The hollow sleeve has a first end, a second end, and an internal surface. The hollow sleeve is slidingly supported and rotationally coupled to the drive shaft at its internal surface and joined to the drive rod at its first end. The hollow outer member is at least partially disposed about the inner drive rod apparatus. The outer member is independently rotatable relative to the inner drive rod apparatus. The at least one stop member is supported by the outer member and configured to engage with the second end of the hollow member. In another aspect the invention is directed to an assembly for connecting a dual-member drill string to a gearbox. The dual-member drill string comprises independently rotatable inner and outer members. The assembly comprises an inner assembly, an outer assembly, and a stop member. The inner assembly is connected at a first end to the gearbox and a second end to the rotatable inner member of the dual-member drill string. The inner assembly comprises a drive shaft, a drive rod, and a hollow sleeve. The drive shaft is rotatable about a longitudinal axis and has a first outer diameter. The drive rod is configured for torque transmitting connection to the rotatable inner member. The hollow sleeve has a second outer diameter and is joined to the drive rod and partially surrounding the drive shaft in a torque-transmitting relationship. The hollow sleeve is configured to move axially relative to the drive shaft. The outer assembly comprises a cavity in which the hollow sleeve and drive shaft are partially housed. The cavity defines a first inner diameter. The first inner diameter is greater than the first outer diameter and the second outer diameter. The stop member is disposed through the outer assembly and extends into the cavity. An effective inner diameter of the cavity at the stop member is greater than the first outer diameter and less than the second outer diameter. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is dual pipe drill gearbox for use with a horizontal directional drilling machine. FIG. 2 is a top view cross section of the gearbox of FIG. 1. FIG. 3 is a perspective view of the spindle assembly as shown in FIG. 1. The gearbox shown in FIGS. 1-2 is attached to the right of the figure. FIG. 4 is a cross section of the spindle assembly attached to the gearbox with the sliding sleeve and inner drive rod in a first position. FIG. 5 is the cross section of the spindle assembly of FIG. 4 with the sliding sleeve and inner drive rod in a second, limiting position with the sleeve contacting a dowel rod. FIG. 6 is a cross sectional end view of the spindle assembly showing a cross-section taken through line 6-6 of FIG. 5. FIG. 7 is a perspective view of the spindle assembly with a portion of the outer member of the spindle and retainer socket screws removed so that internal components of the spindle are visible. The sleeve is shown in the first position of FIG. 4. FIG. 8 is a diagrammatic representation of a horizontal directional drilling machine attached to a drill string. FIG. 9 is a sectional side view of a dual-member pipe section for use with the spindle assembly. DETAILED DESCRIPTION In many horizontal directional drilling applications it is preferable to utilize a dual pipe system. Dual pipe systems are particularly useful for drilling through rock, as the rotation of the inner pipe and outer pipe may be used, independently of one another, to drive rotation of a drill bit and to change the orientation of a steering feature. An example of a dual pipe system is disclosed in U.S. Pat. No. 9,765,574, issued to Slaughter, Jr. et al (“Slaughter”), the contents of which are incorporated herein by reference. With reference to FIG. 8 and FIG. 9, a directional drilling machine 10 comprises a carriage 12. The carriage 12 provides axial and rotational force and is configured to connect sections of drill pipe 14