US4359892A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Arrangement for measuring surface profiles
Assignee: USPHILIPS Corp A CORP OF
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Filing: 1980-12-15
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Granted: 1982-11-23
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Expires: 2000-12-15
Abstract
Abstract A surface testing apparatus includes a bilaminar ceramic flexure element provided with means for generating a voltage which is proportional to the deflection of the flexure element. This voltage is compared with a reference voltage. After amplification the difference voltage is applied to the flexure element so that the applied force remains constant, independently of the deflection.
Inventors
- 👤 Axel Schnell
- 👤 Heinrich Oepen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 03:22
CPC Classifications
G; G01; G01B; G01B7/00; G01B7/28
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
107 words
An apparatus for measuring surface profiles comprising, a bilaminar ceramic flexure element supporting a test probe that is movable over a surface to be tested, the flexure element including means for generating a voltage which is proportional to the deflection of the flexure element, means for comparing the generated voltage with a source of reference voltage and for amplifying a difference voltage that results from the comparison of the generated and reference voltages, and means for applying the amplified difference voltage to the flexure element such that the applied force of the test probe on the tested surface is independent of the deflection of the flexure element.
Claim 2
Independent Claim
107 words
An apparatus for measuring surface profiles comprising, a bilaminar ceramic flexure element supporting a test probe that is movable over a surface to be tested, the flexure element including means for generating a voltage which is proportional to the deflection of the flexure element, means for comparing the generated voltage with a source of reference voltage and for amplifying a difference voltage that results from the comparison of the generated and reference voltages, and means for applying the amplified difference voltage to the flexure element such that the applied force of the test probe on the tested surface is independent of the deflection of the flexure element.
Claim 3
Dependent Claim
72 words
An apparatus as claimed in claim 1 wherein said voltage generating means comprises, first and second strain gauges supported on the flexure element at a point located near a fixed support point of the flexure element, and a bridge circuit including said first and second strain gauges, said strain gauges producing a resistance variation proportional to the flexure element deflection which are converted into a corresponding voltage variation in said bridge circuit.
Claim 4
Dependent Claim
23 words
An apparatus as claimed in claim 1 or 2 wherein said comparing and amplifying means includes an amplifier having an adjustable gain factor.
Claim 5
Independent Claim
20 words
An apparatus as claimed in claims 1 or 2 wherein the flexure element is made of an electrostrictive ceramic material.
Claim 6
Independent Claim
20 words
An apparatus as claimed in claims 1 or 2 wherein the flexure element is made of a polarized piezoceramic material.
Claim 7
Independent Claim
33 words
An apparatus as claimed in claims 1 or 2 further comprising means for adjusting the level of the reference voltage thereby to adjust the value of said applied force of the test probe.
Claim 8
Dependent Claim
152 words
A surface testing apparatus comprising a test probe movable over the surface to be tested and supported near one end of a bilaminar ceramic flexure element, said flexure element being supported at an opposite end thereof, means mechanically coupled to the flexure element for generating a voltage proportional to the deflection of the flexure element, a source of reference voltage which determines the value of applied force between the test probe and test surface, means coupled to said voltage generating means and said reference voltage source for comparing the generated voltage and the reference voltage to derive a difference voltage determined by the deflection of the flexure element, and means for applying said difference voltage to the flexure element so as to deflect the flexure element in a sense to maintain the applied force between the test probe and test surface relatively constant and independent of the deflection of the flexure element.
Claim 9
Dependent Claim
152 words
A surface testing apparatus comprising a test probe movable over the surface to be tested and supported near one end of a bilaminar ceramic flexure element, said flexure element being supported at an opposite end thereof, means mechanically coupled to the flexure element for generating a voltage proportional to the deflection of the flexure element, a source of reference voltage which determines the value of applied force between the test probe and test surface, means coupled to said voltage generating means and said reference voltage source for comparing the generated voltage and the reference voltage to derive a difference voltage determined by the deflection of the flexure element, and means for applying said difference voltage to the flexure element so as to deflect the flexure element in a sense to maintain the applied force between the test probe and test surface relatively constant and independent of the deflection of the flexure element.
Claim 10
Dependent Claim
65 words
An apparatus as claimed in claim 7 wherein the comparing means comprises a differential amplifier, and the voltage generating means includes strain gauge means fixed to the flexure element and an electrical bridge circuit including the strain gauge means, said strain gauge means producing a resistance variation proportional to the flexure element deflection which is converted into a corresponding voltage variation in said bridge circuit.
Claim 11
Dependent Claim
48 words
An apparatus as claimed in claim 7 wherein said flexure element is adapted to be mounted so that it is deflected in a direction normal to the test surface and said difference voltage is applied to the flexure element so as to deflect same in said normal direction.
References Cited (Backward Citations)
US2728222A
Cited
US4310913A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-11-22 | 1986-05-24 | 1986-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-22 | 1990-05-24 | 1990-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-22 | 1994-05-24 | 1994-11-23 | $7700.00 | Window Closed / Lapsed |