US4694690A — Measuring displacement between two relatively mov…

Claim 1

Independent Claim 128 words

A method of measuring movement of a railway rail with respect to an underlying structure, wherein a first device is fixed with respect to the rail and a second device is fixed with respect to the underlying structure, one of these devices including a split field filter and the other including first means for directing light at the filter and second means for transmitting light which has passed through the filter, and wherein there is supplied to the first means light of two wavelengths and the light which has passed through the filter, which is affected by the position of the filter with respect to the first and second means, is used to provide a measure of the movement of the rail with respect to the underlying structure.

Claim 2

Independent Claim 128 words

A method of measuring movement of a railway rail with respect to an underlying structure, wherein a first device is fixed with respect to the rail and a second device is fixed with respect to the underlying structure, one of these devices including a split field filter and the other including first means for directing light at the filter and second means for transmitting light which has passed through the filter, and wherein there is supplied to the first means light of two wavelengths and the light which has passed through the filter, which is affected by the position of the filter with respect to the first and second means, is used to provide a measure of the movement of the rail with respect to the underlying structure.

Claim 3

Dependent Claim 40 words

A method as claimed in claim 1, wherein pulsed light is supplied to the first means in such a manner that pulses of light at one of the wavelengths alternate with pulses of light at the other of the wavelengths.

Claim 4

Dependent Claim 41 words

A method as claimed in claim 1, in which there is provided a feedback signal to hold the intensity of light at one of the wavelengths supplied to the first means substantially equal to that at the other of the wavelengths.

Claim 5

Dependent Claim 29 words

A method as claimed in claim 3 in which the sum of the intensities of the two wavelengths of light transmitted by the second means is held substantially constant.

Claim 6

Dependent Claim 106 words

An installation comprising a railway rail supported by an underlying structure, a first device fixed with respect to the rail, a second device fixed with respect to the structure, one of these devices including a split field filter and the other carrying first means for directing light at the filter and second means for transmitting light which has passed through the filter, third means for generating and supplying to the first means light of two wavelengths and fourth means for receiving light transmitted from the second means and using it to provide a measure of the movement of the rail with respect to the underlying structure.

Claim 7

Dependent Claim 106 words

An installation comprising a railway rail supported by an underlying structure, a first device fixed with respect to the rail, a second device fixed with respect to the structure, one of these devices including a split field filter and the other carrying first means for directing light at the filter and second means for transmitting light which has passed through the filter, third means for generating and supplying to the first means light of two wavelengths and fourth means for receiving light transmitted from the second means and using it to provide a measure of the movement of the rail with respect to the underlying structure.

Claim 8

Dependent Claim 54 words

An installation as claimed in claim 5 in which the third means comprises pulsing means for alternately supplying light at one and then the other of the wavelengths to the first means, there being timing and sensing means arranged to operate in synchronism with the pulsing means to sense light transmitted via the filter.

Claim 9

Dependent Claim 37 words

An installation as claimed in claim 5, which includes feedback means for maintaining the intensity of light generated at one of the wavelengths substantially equal to the intensity of light generated at the other of the wavelengths.

Claim 10

Dependent Claim 33 words

An installation as claimed in claim 7 which includes means for maintaining the sum of intensities of light sensed at the fourth means at the two wavelengths equal to a predetermined reference value.

Claim 11

Dependent Claim 67 words

An installation as claimed in claim 5, in which the fourth means includes means for providing an analogue output proportional to said movement, the output Vo being given by ##EQU3## Where IW1, IW2 are the intensitites of the generated light at wavelengths W1, W2 respectively and m, m' are the proportions of that intensity directed to the fourth means via the filter of wavelengths W1, W2 respectively.

Claim 12

Dependent Claim 35 words

An installation as claimed in claim 5, which comprises a plurality of sets of first and second devices mounted with their filters so arranged as to measure displacement in at least two mutually orthogonal directions.

Claim 13

Dependent Claim 187 words

Apparatus for use to measure the relative displacement between two structures, the apparatus comprising: a first device including transmission means for directing light of two wavelengths from a source and to a sensing means; a first mounting element for supporting the first device and having alignment means for positioning the first device relative thereto; a second device including a split field filter; a second mounting element for supporting the second device; jig means configured to support the first mounting element to bring it into contact with one of the structures during installation; a locating member having locating means cooperable with the alignment means of the first mounting element to locate the second mounting element on the other one of the structures at a desired position with respect to the first mounting element, when the latter has been mounted relative to said one of the structures, so that, with the first and second devices supported respectively by the first and second mounting elements, light of two wavelengths transmitted from a source is directed via the filter to a sensing means thereby to sense relative displacement between the structures.

Claim 14

Dependent Claim 187 words

Apparatus for use to measure the relative displacement between two structures, the apparatus comprising: a first device including transmission means for directing light of two wavelengths from a source and to a sensing means; a first mounting element for supporting the first device and having alignment means for positioning the first device relative thereto; a second device including a split field filter; a second mounting element for supporting the second device; jig means configured to support the first mounting element to bring it into contact with one of the structures during installation; a locating member having locating means cooperable with the alignment means of the first mounting element to locate the second mounting element on the other one of the structures at a desired position with respect to the first mounting element, when the latter has been mounted relative to said one of the structures, so that, with the first and second devices supported respectively by the first and second mounting elements, light of two wavelengths transmitted from a source is directed via the filter to a sensing means thereby to sense relative displacement between the structures.

Claim 15

Dependent Claim 56 words

Apparatus as claimed in claim 11, in which the jig means is provided with a locking mechanism for retaining it, by means of said other of the structures, in place with the first mounting element in contact with said one of the structures while said first mounting element is secured to that one of the structures.

Claim 16

Dependent Claim 52 words

Apparatus as claimed in claim 12 when used to measure the displacement between a railway rail and an underlying structure, in which the locking mechanism has a fast release manually operable portion whereby the jig means can be released quickly in the event of a train using the railway rail during installation.

Claim 17

Dependent Claim 65 words

Apparatus as claimed in claim 11, in which the jig means is so configured as to support two such first mounting elements at predetermined positions relative to one another so that the first mounting elements can be mounted on said one structure with a predetermined separation so that relative displacement of two parts of the one structure relative to the other structure can be determined.

Claim 18

Dependent Claim 20 words

Apparatus as claimed in claim 11 when used to measure the displacement between a railway rail and an underlying structure.

Claim 19

Independent Claim 205 words

A method of installing apparatus for measuring the relative displacement between two structures, the method comprising: mounting a first mounting element, having alignment means, relative to one of the structures using a jig means configured to support the first mounting element to bring it into contact with said one of the structures; using a locating member having locating means cooperable with the alignment means of the first mounting element to locate a second mounting element on the other one of the structures at a desired position with respect to the first mounting element; mounting the second mounting element to the other one of the structures at that desired position; removing the locating member and securing to the first mounting element at a position determined by the alignment means a first device including transmission means for directing light of two wavelengths from a source and to a sensing means and securing to the second mounting element a second device including a split field filter, so that, with the first and second devices supported respectively by the first and second mounting elements, light of two wavelengths transmitted from a source is directed via the filter to the sensing means thereby to sense relative displacement between the structures.

Claim 20

Independent Claim 205 words

A method of installing apparatus for measuring the relative displacement between two structures, the method comprising: mounting a first mounting element, having alignment means, relative to one of the structures using a jig means configured to support the first mounting element to bring it into contact with said one of the structures; using a locating member having locating means cooperable with the alignment means of the first mounting element to locate a second mounting element on the other one of the structures at a desired position with respect to the first mounting element; mounting the second mounting element to the other one of the structures at that desired position; removing the locating member and securing to the first mounting element at a position determined by the alignment means a first device including transmission means for directing light of two wavelengths from a source and to a sensing means and securing to the second mounting element a second device including a split field filter, so that, with the first and second devices supported respectively by the first and second mounting elements, light of two wavelengths transmitted from a source is directed via the filter to the sensing means thereby to sense relative displacement between the structures.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1990-09-21	1991-03-23	1991-09-22	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1994-09-21	1995-03-23	1995-09-22	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1998-09-21	1999-03-23	1999-09-22	$7700.00	Window Closed / Lapsed

Measuring displacement between two relatively movable structures

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