US3891017A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Combination screw and screwdriver with axial guide spigot
Assignee: Individual
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Filing: 1974-02-22
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Granted: 1975-06-24
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Expires: 1994-02-22
Abstract
Abstract For use with screws having a slotted head and a central axial bore, a screwdriver blade is provided with a diametral blade tip and a central guide spigot extending axially beyond the tip and of greater cross-section than the top width. The spigot, which may be cylindrical or of square cross-section, serves to maintain the screw in co-axial relationship with the screwdriver and prevents the blade slipping out of the slot in use. The combination of a screw and screwdriver of the above type is described, preferably the spigot is of less length than the depth of the axial bore to prevent bottoming therein and, in the case of the square-section spigot it is sized to be a press fit in the bore so that the corners bite into the bore wall for more positive location.
Inventors
- 👤 Marian Iskra
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:21
CPC Classifications
B; B25; B25B; B25B15/00; B25B15/001; B25B15/004; B25B15/007; F; F16; F16B; F16B23/00; F16B23/0007; F16B23/0015
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
159 words
The combination of a screw having a head including a transverse parallel-sided slot and a central axial cylindrical bore of greater depth than the slot and of constant diameter throughout its length, which diameter is greater than the width of the slot; and a screwdriver blade comprising a straight edged diametrally extending blade tip for rotational driving engagement with said slot and a central guide spigot porjecting axially substantially beyond the blade tip for operative entry into said axial bore and having a square lateral cross-section substantially greater in width throughout its length than the width of said tip for engagement in said axial bore, the diagonal of said spigot being substantially equal to the diameter of the axial bore, and said spigot being slightly tapered toward its free end and dimensioned to have a press fit in said bore, whereby the corners of said spigot are adapted to have biting engagement with the wall of said axial bore.
Claim 2
Dependent Claim
159 words
The combination of a screw having a head including a transverse parallel-sided slot and a central axial cylindrical bore of greater depth than the slot and of constant diameter throughout its length, which diameter is greater than the width of the slot; and a screwdriver blade comprising a straight edged diametrally extending blade tip for rotational driving engagement with said slot and a central guide spigot porjecting axially substantially beyond the blade tip for operative entry into said axial bore and having a square lateral cross-section substantially greater in width throughout its length than the width of said tip for engagement in said axial bore, the diagonal of said spigot being substantially equal to the diameter of the axial bore, and said spigot being slightly tapered toward its free end and dimensioned to have a press fit in said bore, whereby the corners of said spigot are adapted to have biting engagement with the wall of said axial bore.
Claim 3
Dependent Claim
21 words
The combination according to claim 1 wherein the axial bore is somewhat greater in depth than the length of the spigot.
Claim 4
Dependent Claim
22 words
The combination according to claim 1 wherein the length of the axial bore is at least twice the depth of the slot.
Claim 5
Dependent Claim
36 words
The combination according to claim 1 wherein the cross-sectional area of the material of the screw around or adjacent to the bore is not less than the cross-sectional area of the material at the thread roots.
Claim 6
Dependent Claim
13 words
The combination according to claim 1 wherein the screw is a countersunk-headed woodscrew.
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) | 1978-06-23 | 1978-12-23 | 1979-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-23 | 1982-12-23 | 1983-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-23 | 1986-12-23 | 1987-06-24 | $7700.00 | Window Closed / Lapsed |