Composite tension/compression strut

Patent metadata

Field	Value
Publication number	US-2016153489-A1
Application number	US-201514949310-A
Country	US
Kind code	A1
Filing date	Nov 23, 2015
Priority date	Nov 28, 2014
Publication date	Jun 2, 2016
Grant date	—

Abstract

A composite filament-wound shaft with an end fitting mounted on an interface region on at least one end of said shaft, wherein in said interface region filaments of the filament-wound shaft are angled with respect to the shaft axis such that they follow a path with a radial component and have been cut so as to expose the ends of said filaments in said interface region; and wherein said end fitting comprises a helical thread engaging with said interface region. The helical threaded engagement provides excellent load transmission of axial forces and is therefore well suited to tension and compression elements. The joint provides a low cost and low weight interface.

First claim

1 . A composite filament-wound shaft with an end fitting mounted on an interface region on at least one end of said shaft,
wherein in said interface region filaments of the filament-wound shaft are angled with respect to the shaft axis such that they follow a path with a radial component and have been cut so as to expose the ends of said filaments in said interface region; and wherein said end fitting comprises a helical thread engaging with said interface region.

2 . A shaft as claimed in claim 1 , wherein said end fitting further comprises grooves across the helical thread that break the helical thread into a plurality of part-helices.

3 . A shaft as claimed in claim 2 , wherein said grooves are axial grooves or helical grooves.

4 . A shaft as claimed in claim 2 , comprising four axial grooves across the helical threads.

5 . A shaft as claimed in claim 1 , wherein the thread is a single-start thread.

6 . A shaft as claimed in claim 1 , wherein said thread has a profile that comprises a cutting tooth portion arranged to cut into said interface region and a substantially flat land portion that frictionally engages with said interface region.

7 . A shaft as claimed in claim 6 , wherein said profile further comprises at least one channel portion adjacent to said cutting tooth portion to accommodate debris produced during a mounting process.

8 . A shaft as claimed in claim 1 , wherein the interface region of the shaft comprises a ramp of hoop-wound fibres that increases in thickness in the axial direction of the shaft towards the end of the shaft, and helical-wound fibres wound over said ramp.

9 . A shaft as claimed in claim 8 , wherein said helical-wound fibres over said ramp have been cut or ground parallel to the axis of the shaft to expose the fibre ends and form said interface region.

10 . A method of mounting an end fitting onto a composite filament-wound shaft,
the end fitting comprising a helical thread; the shaft comprising an interface region in which filaments of the filament-wound shaft are angled with respect to the shaft axis such that they follow a path with a radial component and have been cut so as to expose the ends of said filaments in said interface region; the method comprising screwing said end fitting onto said shaft.

11 . A method as claimed in claim 10 , wherein the end fitting is driven axially at a rate equal to one thread pitch per rotation.

Assignees

• Crompton Technology Group Ltd

Inventors

• Pollitt William
• Chase Ian Thomas

Classifications

• F16C3/026 Primary

  Shafts made of fibre reinforced resin · CPC title

• F16D1/072

  involving plastic deformation (plastic welding F16D1/068) · CPC title

• B29C53/585

  the cross-section varying along their axis, e.g. tapered, with ribs, or threads, with socket-ends · CPC title

• F16C2326/06

  Drive shafts · CPC title

• F16D1/076

  by clamping together two faces perpendicular to the axis of rotation, e.g. with bolted flanges · CPC title