US3827331A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-extruding screw
Assignee: Research Engineering and Manufacturing Inc
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Filing: 1972-11-01
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Granted: 1974-08-06
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Expires: 1992-11-01
Abstract
Abstract A self-extruding screw comprises a shank with a thread-forming section and a lead section. The thread-forming section may be of arcuate polygonal cross-section. A lead section is adjacent to the thread-forming section and has ribs that are helically disposed opposite to the helix of the thread of the threadforming section to enlarge, extrude and cold work a pilot hole in a workpiece. The ribs may be eccentric or concentric with respect to the axis of the shank, depending upon whether or not the screw is to be captive with the workpiece. The lead section may also include a drill point to form the pilot hole.
Inventors
- 👤 H Muenchinger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:46
CPC Classifications
F; F16; F16B; F16B25/00; F16B25/0036; F16B25/0042; F16B25/0057; F16B25/001; F16B25/0021; F16B25/10; F16B25/103
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
154 words
A screw comprising a shank having a threaded section of a type that forms a thread in a workpiece opening, said threaded section having a central axis, the thread on said threaded section being helically disposed about said axis and including a crest, and a lead section having helically disposed ribs with rounded crests for extruding the workpiece opening for subsequent threading by said threaded section, the maximum radial distance from said axis to the crests of said ribs being less than the maximum radial distance from said axis to the crest of the thread, the helix angle of the ribs being substantially greater than the helix angle of the thread and the helical disposition of said ribs being opposite to the helical disposition of said thread whereby the ribs extrude a flange at the opening in the direction of penetration of the screw into the workpiece substantially without an internal helical deformation therein.
Claim 2
Dependent Claim
154 words
A screw comprising a shank having a threaded section of a type that forms a thread in a workpiece opening, said threaded section having a central axis, the thread on said threaded section being helically disposed about said axis and including a crest, and a lead section having helically disposed ribs with rounded crests for extruding the workpiece opening for subsequent threading by said threaded section, the maximum radial distance from said axis to the crests of said ribs being less than the maximum radial distance from said axis to the crest of the thread, the helix angle of the ribs being substantially greater than the helix angle of the thread and the helical disposition of said ribs being opposite to the helical disposition of said thread whereby the ribs extrude a flange at the opening in the direction of penetration of the screw into the workpiece substantially without an internal helical deformation therein.
Claim 3
Dependent Claim
26 words
A screw according to claim 1 in which the lead section has a central axis that is eccentric to the central axis of the threaded section.
Claim 4
Dependent Claim
74 words
A screw according to claim 1 in which the thread on said threaded section has a crest cross section formed by circumferentially spaced lobes joined by arcuate sides, said maximum radial distance from said axis to the crests of said ribs being less than the maximum radial distance from said axis to the crests at said lobes but greater than the minimum radial distance from said axis to the crests at said arcuate sides.
Claim 5
Dependent Claim
49 words
A screw according to claim 1 in which the lead section further includes a drill point for forming the opening in the workpiece, said drill point having a radial thickness from said axis that is less than said radial distance from said axis to the crests of said ribs.
Claim 6
Dependent Claim
47 words
A screw according to claim 3 in which said lead section includes a drill point for forming an opening in the workpiece, said drill point having a radial thickness from said axis that is less than the minimum radial distance from said axis to an arcuate side.
Claim 7
Dependent Claim
39 words
A screw according to claim 1 in which the radial distance of the crests of the ribs from said axis pregressively decreases in a direction toward the work-entering end of the screw whereby the ribs present a tapered profile.
References Cited (Backward Citations)
US1643679A
Cited
US3195156A
Cited
US3156152A
Cited
US3438299A
Cited
US3739682A
Cited
US3648560A
Cited
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Cited
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Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-08-05 | 1978-02-04 | 1978-08-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-05 | 1982-02-04 | 1982-08-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-05 | 1986-02-04 | 1986-08-06 | $7700.00 | Window Closed / Lapsed |