US3579922A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for abrading articles
Assignee: AT&T Inc
•
Filing: 1968-10-11
•
Granted: 1971-05-25
•
Expires: 1988-10-11
Abstract
Abstract Apparatus for fine lapping of thin piezoelectric crystals to a desired resonant frequency characteristic includes a number of holders urging and lapping the crystals against a vibrating, relatively movable lapping plate bearing very fine abrasive particles. Probes are successively pivoted into engagement with selected holders, one at a time, during lapping to sample the instant resonant frequency of each of the vibrating crystals by coupling the crystals successively into a test circuit. While lapping of the other crystals continues, a crystal which has attained the desired frequency characteristic may be withdrawn with its holder and replaced by another holder and crystal.
Inventors
- 👤 Nicholas J Mandonas
- 👤 Paul A Ryll
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 05:14
CPC Classifications
B; B24; B24B; B24B37/00; B24B37/005; B24B37/013; B24B35/00; B24B37/04; B24B49/00; B24B49/02; B24B49/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
95 words
In apparatus for lapping a piezoelectric crystal: a fixed holder for the crystal; a relatively movable lapping member positioned to contact the crystal on said holder; means for moving said lapping member with respect to the holder during said contact to reduce the thickness of the held crystal, said means comprising means for vibrating the lapping member to excite the crystal; and circuit means, completable through the held crystal and rendered effective when completed upon excitation of the crystal with movement of said lapping member, for measuring the instant resonant frequency of the excited crystal.
Claim 2
Dependent Claim
145 words
In apparatus for lapping piezoelectric crystals: a first fixed holder for a first crystal; a relatively movable lapping member positioned to contact the first crystal on said holder; means for moving said lapping member with respect to the holder during said contact to reduce the thickness of the first crystal; at least one additional relatively fixed crystal holder located adjacent said movable lapping member in position to lap another crystal between the additional crystal holder and the relatively movable lapping member; means for removably mounting each of said holders in the fixed position thereof such that at least one of the crystal holders may be removed during movement of said lapping member; and circuit means completable through each held crystal and rendered effective during movement of said lapping member for measuring the instant resonant frequency of each crystal through which the circuit means is completed.
Claim 3
Dependent Claim
70 words
In apparatus for lapping crystals, as set forth in claim 3: said crystal holders each being composed of an electrically conductive material; said holder-mounting means being composed of a dielectric material so as to electrically isolate the crystal holders from each other; and said circuit means including an electrical conductive probe mounted for engaging one of said crystal holders to measure the frequency of a crystal held thereby during lapping.
Claim 4
Dependent Claim
102 words
In apparatus for lapping piezoelectric crystals to vary the resonant frequency of the crystals: a plurality of holders for the crystals; a lapping plate mounted for movement; means removably mounting each of said holders fixed with respect to said lapping plate and positioned to urge the crystals held by the holders against the lapping plate for lapping the crystals upon movement of the lapping plate; means for vibrating and moving said lapping plate to excite and lap the crystals; and means operated during the vibration and movement of said lapping plate for measuring the instant resonant frequency of a crystal being lapped.
Claim 5
Dependent Claim
139 words
In apparatus for lapping piezoelectric crystals to adjust the crystals to a predetermined resonant frequency value: a fixed plate having a pair of opposite faces and having a plurality of apertures extending through the fixed plate between said faces; a lapping plate having a lapping surface and mounted for movement with the lapping surface maintained adjacent one of said faces of the fixed plate; individual holder means removably positionable in said apertures of the fixed plate for releasably holding a crystal and urging the crystal against said lapping surface of the lapping plate to be lapped upon Movement of the lapping plate; means for moving the lapping plate to lap the held crystals; and means selectively monitoring the instant resonant frequency of the held crystals during continued lapping for indicating that a held crystal has attained the predetermined value.
Claim 6
Dependent Claim
31 words
In apparatus for lapping piezoelectric crystals, as set forth in claim 6, said lapping plate moving means comprising: means for vibrating the lapping plate during movement to excite the held crystals.
References Cited (Backward Citations)
US2340843A
Cited
US2687603A
Cited
US2922264A
Cited
US3088247A
Cited
US2884746A
Cited
US2984951A
Cited
US2983086A
Cited
US3063206A
Cited
US3097458A
Cited
US3027689A
Cited
US3350817A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-24 | 1974-11-23 | 1975-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-24 | 1978-11-23 | 1979-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-24 | 1982-11-23 | 1983-05-25 | $7700.00 | Window Closed / Lapsed |