US4705441A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self locking sheet metal screw
Assignee: Illinois Tool Works Inc
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Filing: 1986-02-12
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Granted: 1987-11-10
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Expires: 2006-02-12
Abstract
Abstract A fastener for attaching sheet metal or articles to sheet metal. The fastener is a self-locking sheet metal screw having a plurality of equally spaced teeth formed within a recess beneath the fastener head during the heading operation. The teeth preferably have curved trailing edges and straight or slightly inclined leading edges, and each extends laterally a different distance from the shank, as well as vertically a different distance along the shank, such lateral and vertical distances on a single tooth being equal.
Inventors
- 👤 Larry J. Arnold
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:55
CPC Classifications
F; F16; F16B; F16B35/00; F16B35/04; F16B35/041; F16B35/048; F16B39/00; F16B39/22; F16B39/28; F16B39/282
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
131 words
A screw fastener comprising: a generally cylindrical shank; an enlarged head on one end of said shank, said head having drive tool engaging means; said shank having at least one helical thread thereon; said head having a lower annular peripheral flange concentric to the axis of said shank, said flange having a recessed portion beneath said head; a plurality of equi-angularly spaced teeth beneath said head and within said recess, each tooth being fixed to said head and to said shank, and each tooth having a tooth height equal to the lateral distance the tooth extends outwardly from said shank; each tooth having a leading flat face and a trailing curved surface; and each successive tooth, except the shortest tooth, extending incrementally further outwardly from said shank than an adjacent tooth.
Claim 2
Dependent Claim
131 words
A screw fastener comprising: a generally cylindrical shank; an enlarged head on one end of said shank, said head having drive tool engaging means; said shank having at least one helical thread thereon; said head having a lower annular peripheral flange concentric to the axis of said shank, said flange having a recessed portion beneath said head; a plurality of equi-angularly spaced teeth beneath said head and within said recess, each tooth being fixed to said head and to said shank, and each tooth having a tooth height equal to the lateral distance the tooth extends outwardly from said shank; each tooth having a leading flat face and a trailing curved surface; and each successive tooth, except the shortest tooth, extending incrementally further outwardly from said shank than an adjacent tooth.
Claim 3
Dependent Claim
21 words
A fastener according to claim 1 wherein each tooth extends outwardly a different distance from the central axis of the shank.
Claim 4
Dependent Claim
27 words
A fastener according to claim 1 wherein said flat face of each tooth varies from the perpendicular to the head plus or minus zero to 15 degrees.
Claim 5
Dependent Claim
19 words
A fastener according to claim 1 wherein the end of said shank opposite said head terminates in a point.
Claim 6
Dependent Claim
17 words
A fastener according to claim 1 wherein the end of said shank opposite said head is tapered.
Claim 7
Dependent Claim
24 words
A fastener according to claim 1 wherein the horizontal radius of each tooth is from 0.50 to 0.75 times the height of such tooth.
Claim 8
Dependent Claim
16 words
A fastener according to claim 1 wherein the thread on said shank is a machine thread.
Claim 9
Dependent Claim
17 words
A fastener according to claim 1 wherein the thread on said screw is a tapping screw thread.
Claim 10
Dependent Claim
24 words
A fastener according to claim 1 wherein the uppermost two thread turns are formed with greater space between them than the lower thread turns.
Claim 11
Dependent Claim
22 words
A fastener according to claim 1 wherein the uppermost two thread turns have a larger outside dimension than the lower thread turns.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-11-09 | 1991-05-11 | 1991-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-11-09 | 1995-05-11 | 1995-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-11-09 | 1999-05-11 | 1999-11-10 | $7700.00 | Window Closed / Lapsed |