Patent US3673912A successfully refreshed from Google Patents.
US3673912A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removable tamperproof fastening means
Assignee: Individual
•
Filing: 1971-02-25
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Granted: 1972-07-04
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Expires: 1991-02-25
Abstract
Abstract A head member is provided for a fastening means such as a screw, nut or bolt which can be turned in a direction to fasten the fastening means yet can be turned in a loosening direction only by a specially adapted tool. The head member has a transverse slot with two oppositely disposed shoulders which permit the turning of the head in a fastening direction. Two upwardly extending curved portions are provided which cause a slipping of a screwdriver when it is attempted to remove the fastening means. Removal is afforded by a notch extending into the head at the end of the slot which permits engagement by a projection on a specially adapted removing means.
Inventors
- 👤 George E Herr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:04
CPC Classifications
F; F16; F16B; F16B23/00; F16B23/0076; Y; Y10; Y10S; Y10S411/00; Y10S411/919
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
145 words
A removable tamperproof fastening means comprising a head portion and a threaded stem portion, two oppositely disposed raised sections extending outwardly from said head portion, each said raised section provided with opposing outwardly curved portions and shoulder abutment portions, said shoulder abutment portions and said curved portions spaced diametrically opposite from each other and apart to provide a slot across the surface of said head portions, said curved portions extending outwardly from said slot and constructed and arranged to form cam surfaces to prevent engagement by a standard screwdriver when turning in an unfastening direction and a single notch extending into said head portion from the periphery of said head portion at the end of said slot and adjacent one said shoulder abutment portion whereby said notch and said adjacent shoulder abutment portion provide opposing engagement portions for turning said head in an unfastening direction.
Claim 2
Dependent Claim
145 words
A removable tamperproof fastening means comprising a head portion and a threaded stem portion, two oppositely disposed raised sections extending outwardly from said head portion, each said raised section provided with opposing outwardly curved portions and shoulder abutment portions, said shoulder abutment portions and said curved portions spaced diametrically opposite from each other and apart to provide a slot across the surface of said head portions, said curved portions extending outwardly from said slot and constructed and arranged to form cam surfaces to prevent engagement by a standard screwdriver when turning in an unfastening direction and a single notch extending into said head portion from the periphery of said head portion at the end of said slot and adjacent one said shoulder abutment portion whereby said notch and said adjacent shoulder abutment portion provide opposing engagement portions for turning said head in an unfastening direction.
Claim 3
Dependent Claim
21 words
The removable tamperproof fastening means as defined in claim 1 wherein said threaded stem portion is of the pointed screw type.
Claim 4
Dependent Claim
20 words
The removable tamperproof fastening means as defined in claim 1 wherein said threaded stem portion is of the bolt type.
Claim 5
Dependent Claim
22 words
The removable tamperproof fastening means as defined in claim 1 wherein said threaded stem portion is of the extended, internally threaded type.
Claim 6
Dependent Claim
19 words
The removable tamperproof fastening means as defined in claim 1 wherein said notch extends completely through the head portion.
Claim 7
Dependent Claim
26 words
The removable tamperproof fastening means as defined in claim 1 wherein each said raised portion comprises approximately quarter of the upper area of said head portion.
Claim 8
Dependent Claim
17 words
The removable tamperproof fastening means as defined in claim 7 wherein said abutment portions are substantially coterminous.
Claim 9
Dependent Claim
24 words
The removable tamperproof fastening means as defined in claim 1 wherein said head portions and said threaded stem portion is composed of hardened steel.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-04 | 1976-01-03 | 1976-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-04 | 1980-01-03 | 1980-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-04 | 1984-01-03 | 1984-07-04 | $7700.00 | Window Closed / Lapsed |