US4358960A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Differential fiber optic proximity sensor
Assignee: Ladd Research Industries Inc
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Filing: 1980-06-26
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Granted: 1982-11-16
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Expires: 2000-06-26
Abstract
Abstract Proximity sensor for determining the distance between a reflective surface and the sensor utilizes two output light guides positioned with the receiving end of one guide closer to the reflective surface than that of the other. When the surface is close to the guide ends a relatively greater intensity of light will be reflected to the second guide; when the surface is further away a relatively greater intensity of light will be reflected to the first guide. At a predetermined intermediate null position the reflected light intensities will be equal. The device has uses, inter alia, in accurately positioning objects without wear-producing contact, e.g. in numerically controlled machine tool operations; thickness sensing or thickness controlling using single or dual sensors; force sensing; liquid level indication; meter relay actuation; rotational limitation, and the like.
Inventors
- 👤 John H. Porter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:50
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/30; G01F23/56; G01F23/60; G01F23/606; A; A61; A61B; A61B5/00; A61B5/02; A61B5/021; A61B5/0215; A61B5/02154; A61B5/03; A61B5/031; G01B; G01B11/00; G01B11/02; G01B11/026; G01D; G01D5/00; G01D5/26; G01D5/268; G01F23/22; G01F23/28; G01F23/284; G01F23/292; G01F23/2921; G01F23/2922; G01F23/2925; G01L; G01L7/00; G01L7/18; G01L9/00; G01L9/0033; G01L9/0039; G01L9/0041; G01L9/0076; G01L9/0077
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
145 words
A sensor for use in apparatus capable of translating the relative intensity of transmitted reflected light into signals indicative of the distance between the sensor and the reflective surface of a body which comprises means for directing light at said surface from a point source; a pair of output light guides arranged with their light receiving ends facing said surface to receive and transmit the light reflected by said surface; the light receiving end of one of said guides, when said sensor is in operative position, being closer to said surface than the other; whereby the intensities of reflected light received and transmitted by said guides will be equal so as to indicate a null when said body is located a predetermined distance from said light receiving ends and will vary differentially as a function of change of distance between said body and said ends.
Claim 2
Dependent Claim
145 words
A sensor for use in apparatus capable of translating the relative intensity of transmitted reflected light into signals indicative of the distance between the sensor and the reflective surface of a body which comprises means for directing light at said surface from a point source; a pair of output light guides arranged with their light receiving ends facing said surface to receive and transmit the light reflected by said surface; the light receiving end of one of said guides, when said sensor is in operative position, being closer to said surface than the other; whereby the intensities of reflected light received and transmitted by said guides will be equal so as to indicate a null when said body is located a predetermined distance from said light receiving ends and will vary differentially as a function of change of distance between said body and said ends.
Claim 3
Dependent Claim
16 words
The combination of claim 1 wherein said means for directing light comprises an input light guide.
Claim 4
Dependent Claim
43 words
The combination of claim 2 wherein said light guides are mounted side by side in a housing and means are provided for adjusting the distance between at least the light receiving end of one of said pair of guides and said reflective surface.
Claim 5
Dependent Claim
26 words
The combination of claim 3 wherein said adjusting means is arranged to shift said housing and light guides in unison toward and away from said surface.
Claim 6
Dependent Claim
45 words
The combination of claim 3 wherein said adjusting means is arranged to shift toward and away from said surface only the one of said pair of output guides whose end, when the sensor is in operative position, is closer to said surface than the other.
Claim 7
Dependent Claim
177 words
The sensor of claim 1, wherein said sensor is adapted for sensing the position of a reflective body relative to the sensor by comparing the intensities of reflected light from the body, the light receiving ends of said pair of guides being so disposed and arranged with respect to said reflective body that, when said body is close to said ends, a greater intensity of light from the input guide will be reflected by the surface of said body to one of said output guides, that, when said body is remote from said ends, a greater intensity of said light will be reflected by the surface of said body to the other of said output guides and, that, when said body is in a null position between said close and remote positions, the intensities of light reflected to said guides will be equal, whereby the intensities of reflected light transmitted by said output guides will vary differentially as a function of change of distance between said body and said ends in either direction from said null position.
Claim 8
Dependent Claim
19 words
The combination of claim 6 including means for detecting the intensities of reflected light transmitted by said output guides.
Claim 9
Dependent Claim
28 words
The combination of claim 7 including means responsive to said detecting means and actuated by a differential variation in said intensities for restoring the body to null position.
Claim 10
Dependent Claim
36 words
The combination of claim 7 wherein said body is a reflective liquid including means for holding said liquid with its surface opposite the ends of said guides whereby the level of said liquid may be sensed.
Claim 11
Dependent Claim
50 words
The combination of claim 7 wherein said body comprises a float having a reflective surface and floating on a liquid and means for holding said liquid and float with the reflective surface of the latter opposite the ends of said guides whereby the level of the liquid may be sensed.
Claim 12
Dependent Claim
71 words
The combination of claim 7 wherein said body comprises a reflector carried by a moving object which moves to at least one specified limiting position, whereby the differential variation of the intensities of reflected light is a function of deviation from said specified limiting position and wherein said sensor is mounted with the light receiving ends of said guides at said null position when said reflector is at said limiting position.
Claim 13
Dependent Claim
85 words
The combination of claim 7 wherein said body comprises reflecting means carried by a moving body which moves to at least one specified limiting position, said sensor being located with respect to said limiting position such that its light receiving guide ends will receive equal intensities of reflected light from said reflecting means only when said body occupies its said specified position whereby differential variation of the intensities of the reflected light is a function of the degree of deviation of said body from specification.
Claim 14
Dependent Claim
25 words
The combination of claim 7 wherein said moving body has more than one limiting position and a sensor is mounted to monitor each such position.
Claim 15
Dependent Claim
16 words
The combination of claim 12 or claim 13 wherein said body is subjected to reciprocating movement.
Claim 16
Dependent Claim
13 words
The combination of claim 12 wherein said body is subjected to rotational movement.
Claim 17
Dependent Claim
82 words
The combination of claim 7 wherein said reflective body comprises a portion of an indicator which moves toward and away from said light receiving ends with change of the conditions indicated by it and means for adjusting the light receiving end of at least one of said light receiving guides toward and away from the body to establish said null position at a predetermined reading of said indicator whereby a signal may be generated each time said indicator reaches said null position.
Claim 18
Dependent Claim
78 words
The sensor of claim 6, wherein said sensor is adapted for measuring the force applied to a resiliently deformable body, said sensor further comprising means for detecting the intensities of reflected light transmitted by said output guides; and means for applying a force to compress said body so that the distance between said reflecting means and said light receiving ends will vary proportionally, whereby said device may be calibrated to a series of nulls for corresponding force values.
Claim 19
Dependent Claim
12 words
The combination of claim 17 wherein said deformable body comprises a spring.
Claim 20
Dependent Claim
12 words
The combination of claim 17 wherein said deformable body comprises a bellows.
Claim 21
Dependent Claim
104 words
The sensor of claim 6, wherein said sensor is adapted for measuring force, said sensor further comprising a bellows; means for applying an unknown force to compress said bellows; reflecting means on a movable surface of said bellows; means for detecting and comparing the intensities of light transmitted by said output guides and generating a differential signal when said intensities are unequal; a fluid pressure generating system responsive to said differential signal and in communication with said bellows for increasing the pressure therein until said transmitted light intensities are equalized, whereby said increased pressure is a measure of the force applied to said bellows.
Claim 22
Dependent Claim
118 words
The sensor of claim 1, wherein said sensor is adapted for gauging thickness, said sensor further comprising means for positioning the reflective surface of a body whose thickness is to be sensed in a predetermined location; whereby the intensities of reflected light received and transmitted by said guides will be equal so as to indicate a null when said body is located a predetermined distance from said light receiving ends and will vary differentially as a function of change of distance between said body and said ends; and means for detecting the intensities of said reflected light and translating the same into signals proportional to the thickness of the body thereby to detect departures from a specified thickness.
Claim 23
Dependent Claim
42 words
The combination of claim 21 including means responsive to said signals for adjusting the thickness of the body for restoring the body to its specified thickness and correspondingly restoring the distance between said surface and said guide ends to the predetermined null.
Claim 24
Dependent Claim
12 words
The combination of claim 22 wherein said body is a travelling sheet.
Claim 25
Dependent Claim
52 words
The combination of claim 21 wherein said light guides are bundled together in a housing mounted in a bracket so as to face said reflective surface, together with means for adjusting at least one of said light receiving ends toward and away from said surface for purposes of establishing said null position.
Claim 26
Dependent Claim
27 words
The combination of claim 24 wherein said adjusting means is arranged to move said housing bodily toward and away from said surface to establish said null position.
Claim 27
Dependent Claim
29 words
The combination of claim 24 wherein said adjusting means is arranged to shift longitudinally the one of said light receiving guides whose receiving end is closer to said surface.
Claim 28
Dependent Claim
121 words
The sensor of claim 1, wherein said sensor is adapted for sensing fluid pressure, said sensor further comprising a bellows in communication with said fluid, said bellows having reflecting means on a movable surface; means for directing light at said reflecting means from a point source; and light detecting means coupled to the outputs of said light guides; whereby the intensities of reflected light received and transmitted by said guides will be equal at a predetermined null position of said reflecting means with respect to said light receiving ends and will vary differentially as a function of change of distance between said ends and said reflecting means thereby permitting calibration of said sensor to a series of nulls for corresponding pressures.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-11-15 | 1986-05-17 | 1986-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-15 | 1990-05-17 | 1990-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-15 | 1994-05-17 | 1994-11-16 | $7700.00 | Window Closed / Lapsed |