Testing glass fibres
AssigneeThe Post Office
InventorPaul W. France
Life of this patent
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Abstract
A method of proof testing an optical glass fibre by pulling it around a free roller whose radius is sufficiently small to impart the strain necessary to detect fibres whose surface or near surface flaws weaken the fibre below a required strength. Proof testers are disclosed incorporating, single rollers, a set of three parallel rollers and a jig holding four sets of three rollers. Proof testers incorporating the extra rollers whose axes are at different angles are shown to more thoroughly explore the surface of the fibre for cracks.
Claims12
A method of proof testing a glass fibre to detect fibres having a strength greater than a predetermined value, the method comprising moving the fibre along a path in which it is bent over the surface of a roller which is free to rotate, the roller having a diameter such that tensile strain induced by bending in the surface of said optical fibre corresponds to the said predetermined value of strength, the fibres being drawn around said roller so that successive portions of said fibre are subjected to the tensile strain induced by bending.
Apparatus for proof-testing glass fibres to detect glass fibres having a strength greater than a predetermined value, said apparatus comprising n sets of m rollers, where n and m are greater than 1, each roller being free to rotate, the rollers of each set of rollers being mounted in a respective one of n support means so that the rotational axes of the rollers in each set are parallel, and means for holding said n support means such that a plane extending perpendicularly through the rotational axes of the rollers of any one set is inclinded to similar planes through the rotational axis of the other sets of rollers, the arrangement being such that when a fibre is drawn through said sets of rollers maximum strain is induced in the fibre at positions substantially evenly distributed about the circumference of said fibre.
Dependencies are inferred from the claim text.