Apparatus for capturing axial force on an inner drive member
AssigneeThe Charles Machine Works, Inc.
InventorMax A. Metcalf
Life of this patent
Estimating the term…
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.
Claims17
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.
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.
Dependencies are inferred from the claim text.