The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 22, 1987
Filed:
Jul. 30, 1986
Pandrol Limited, London, GB;
Abstract
An apparatus for use in measuring relative movement between two structures is described. A support (7) having bores for receiving input and output optical fibres (2, 10) is mounted on a plate (24), secured to one of the structures, at a predetermined position using alignment means (50). A filter (8) is fixed relative to the other structure so that light passing down the input fibre (2) passes through the filter (8) to the output fibre (10). The filter comprises a split field filter so that when light of two wavelengths is transmitted via the input fibre (2), the intensity of light at each wavelength transmitted through the filter (8) depends on the position of the filter relative to the support. An analogue output proportional to the displacement is provided using the transmitted intensities. The invention is particularly applicable to measuring displacement of a railway rail with respect to an underlying structure, and a method and installation for this are described.