US3893365A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plastic screw grommet
Assignee: Illinois Tool Works Inc
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Filing: 1973-12-28
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Granted: 1975-07-08
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Expires: 1993-12-28
Abstract
Abstract A fastening device is disclosed which will not spin even when inserted in a round workpiece aperture. The fastener includes a resinous anchor member having a screw-receiving bore formed at an offset from the anchor shank. The shank surface comprises two frustoconical formations which intersect to form a shoulder; in one embodiment, this locus of intersection is an ellipse. A slot is formed in the anchor shank to permit the shank to expand and engage a surrounding workpiece.
Inventors
- 👤 George E Gross
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:00
CPC Classifications
F; F16; F16B; F16B19/00; F16B19/002; F16B19/004; F16B13/00; F16B13/001; F16B37/00; F16B37/04; F16B37/041; F16B37/043; F16B5/00; F16B5/02; F16B5/025; Y; Y10; Y10S; Y10S411/00; Y10S411/913
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
166 words
A fastening device for use in a workpiece having a round aperture therein, said device including a head and an integral, axially elongated, resilient shank having a generally circular cross-section for intimate acceptance within said aperture, shoulder means located intermediate the ends of said shank for engagement with one surface of the workpiece while said head engages the other surface, a bore traversing said head and a substantial portion of said shank, said bore having an initial diameter smaller than the diameter of a mating screw to cause the shank inserted in said aperture to resiliently expand and engage the surrounding workpiece when the screw is forced along the bore, the bore further having its axis offset and spread-apart from the central axis of the shank an amount sufficient to locate said bore at an eccentric position totally to one side of said shank axis to thereby inhibit rotation of the circular shank in the round workpiece aperture as the screw is turned into the bore.
Claim 2
Dependent Claim
166 words
A fastening device for use in a workpiece having a round aperture therein, said device including a head and an integral, axially elongated, resilient shank having a generally circular cross-section for intimate acceptance within said aperture, shoulder means located intermediate the ends of said shank for engagement with one surface of the workpiece while said head engages the other surface, a bore traversing said head and a substantial portion of said shank, said bore having an initial diameter smaller than the diameter of a mating screw to cause the shank inserted in said aperture to resiliently expand and engage the surrounding workpiece when the screw is forced along the bore, the bore further having its axis offset and spread-apart from the central axis of the shank an amount sufficient to locate said bore at an eccentric position totally to one side of said shank axis to thereby inhibit rotation of the circular shank in the round workpiece aperture as the screw is turned into the bore.
Claim 3
Dependent Claim
29 words
A fastening device according to claim 1 wherein the shank is longitudinally divided by at least one slot extending at least partially across said shank in a diametric direction.
Claim 4
Dependent Claim
37 words
A fastening device according to claim 1 wherein the shank is longitudinally bifurcated by at least one slot having a width less than the bore diameter, said slot extending diametrically across said shank and intersecting the bore.
Claim 5
Dependent Claim
33 words
A fastening device according to claim 1 wherein said bore axis and said shank axis are substantially parallel and are spaced apart by an amount greater than one-half the diameter of the bore.
Claim 6
Dependent Claim
35 words
A fastening device according to claim 1, the surface of said shank is at least partly defined by two intersecting frustoconical surfaces, the locus of intersection defining said shoulder means as an inclined shank shoulder.
Claim 7
Dependent Claim
26 words
A fastening device according to claim 5 wherein said locus of intersection is a circle when viewed in a plane oriented perpendicularly to the shank axis.
Claim 8
Dependent Claim
29 words
A fastening device according to claim 5 wherein said locus of intersection is an ellipse when viewed in a plane oriented at an acute angle to the shank axis.
Claim 9
Dependent Claim
35 words
A fastening device according to claim 7 wherein the locus of frustoconical intersection extends away from the head end of said shank for a distance at least equal to one half said initial bore diameter.
Claim 10
Dependent Claim
49 words
A fastening device according to claim 1 wherein said head is adapted to abuttingly engage a second workpiece above the head, said second workpiece having a screw shank-locating aperture located congruently with said anchor bore for preventing translational movement of the screw as it is forced into the bore.
Claim 11
Dependent Claim
16 words
A fastening device according to claim 1 wherein said device is formed of a resinous plastic.
Claim 12
Dependent Claim
93 words
A fastening device according to claim 1 including a thread-forming screw having a head and a shank of an outer diameter larger than said fastening device unthreaded bore to assure complimentary thread convolution engagement between the screw and the anchor, the length and diameter of said screw shank being sufficient to cause outward flexing of the fastening device as the screw shank is forced into the fastening device bore, said fastening device shank flexing outwardly and frictionally engaging the first surrounding workpiece and thereby inhibiting rotation of the fastening device in the 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) | 1978-07-07 | 1979-01-06 | 1979-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-07 | 1983-01-06 | 1983-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-07 | 1987-01-06 | 1987-07-08 | $7700.00 | Window Closed / Lapsed |