US4069730A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thread-forming screw
Assignee: WALES BEECH CORP
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Filing: 1976-06-03
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Granted: 1978-01-24
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Expires: 1996-06-03
Abstract
Abstract An improved thread-forming screw has a circular threaded main body portion and a tapered lobular pilot or thread-forming section comprising a plurality of transverse elongated projections or lobes on a circular conical core, each lobe having a sharp ridge running the full length thereof. The sharp edges on the lobes minimize the torque required to form threads in a workpiece, while the circular main body portion maximizes the holding power of the screw in the workpiece.
Inventors
- 👤 Charles E. Gutshall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:12
CPC Classifications
F; F16; F16B; F16B25/00; F16B25/001; F16B25/0021; F16B25/0036; F16B25/0042; F16B25/0047; F16B25/0052; F16B25/0084; Y; Y10; Y10S; Y10S411/00; Y10S411/03
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
180 words
A thread-forming screw comprising: an elongated shank including a substantially cylindrical main body portion having a continuous thread formed thereon; means at one end of said body portion cooperable with a tool for turning said screw; a work-entering tapered thread-forming pilot portion at the other end of said body portion; said pilot portion comprising a conical core having a substantially circular cross-section and a plurality of elongated tapping lobes extending outwardly from the surface of said core, each of said lobes having a sharp, fully formed outer ridge along its entire length, the sharp outer ridge on each of said lobes beginning and ending at the juncture of said lobes with said core; said lobes being disposed transversely on said core and spaced so that the outermost point on each of said sharp lobes falls on a helix having the same pitch as the thread on said main body portion and a diameter which increases from a minimum at the work-entering end of said screw to a maximum at the juncture of said pilot portion and said main body portion.
Claim 2
Dependent Claim
180 words
A thread-forming screw comprising: an elongated shank including a substantially cylindrical main body portion having a continuous thread formed thereon; means at one end of said body portion cooperable with a tool for turning said screw; a work-entering tapered thread-forming pilot portion at the other end of said body portion; said pilot portion comprising a conical core having a substantially circular cross-section and a plurality of elongated tapping lobes extending outwardly from the surface of said core, each of said lobes having a sharp, fully formed outer ridge along its entire length, the sharp outer ridge on each of said lobes beginning and ending at the juncture of said lobes with said core; said lobes being disposed transversely on said core and spaced so that the outermost point on each of said sharp lobes falls on a helix having the same pitch as the thread on said main body portion and a diameter which increases from a minimum at the work-entering end of said screw to a maximum at the juncture of said pilot portion and said main body portion.
Claim 3
Dependent Claim
17 words
A screw in accordance with claim 1 wherein said pilot portion has at least two thread pitches.
Claim 4
Dependent Claim
32 words
A screw in accordance with claim 2 wherein each of said pitches has two diametrically opposed lobes, the lobes in adjacent pitches being angularly displaced about the longitudinal axis of said screw.
Claim 5
Dependent Claim
23 words
A screw in accordance with claim 2 wherein each of said pitches has three lobes symmetrically spaced about the circumference of said core.
Claim 6
Dependent Claim
25 words
A screw in accordance with claim 1 wherein the maximum height of each of said lobes above the surface of said core is substantially uniform.
Claim 7
Dependent Claim
33 words
A screw in accordance with claim 1 wherein the maximum height of each of said lobes above the surface of said core decreases in a direction toward the work-entering end of said screw.
Claim 8
Dependent Claim
37 words
A screw in accordance with claim 1 wherein said tapping portion is provided with cutting flutes disposed on said core between said lobes, said flutes being adapted to form or enlarge a pilot hole in a workpiece.
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) | 1981-01-23 | 1981-07-25 | 1982-01-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-23 | 1985-07-25 | 1986-01-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-23 | 1989-07-25 | 1990-01-24 | $7700.00 | Window Closed / Lapsed |