US3793786A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Screw anchor
Assignee: Joslyn Corp
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Filing: 1971-09-08
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Granted: 1974-02-26
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Expires: 1991-09-08
Abstract
Abstract A screw anchor for penetration and holding in soft soil comprising an elongated shank rotatable about its longitudinal axis and having a lower end adapted to penetrate into the earth upon rotation. A helical flight is secured to the shank for holding engagement in the earth and includes a crowned upper surface extending outwardly of the shank and sloping downwardly adjacent the outer edge thereof, thereby increasing the holding strength of the flight by providing a larger, frustoconical, shear area in the soil rather than a smaller cylindrical shear area, as with conventional anchors.
Inventors
- 👤 E Jahnke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:26
CPC Classifications
E; E02; E02D; E02D5/00; E02D5/74; E02D5/80; E02D5/801
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
138 words
A screw anchor for penetration and holding in the earth comprising an elongated shank rotatable about its longitudinal axis and having a lower end portion of polygonal cross-section adapted to penetrate into the earth and a helical flight secured to said lower end portion of said shank for holding engagement in the earth, said helical flight having a diameter substantially greater than the transverse dimension of said shank and having a crowned upper surface extending outwardly of said shank and curved to slope downwardly adjacent the outer edge thereof, said lower end portion including an upper segment above said flight for driving engagement with a tool telescoped thereon, said lower end portion including a lower segment below said flight twisted about said longitudinal axis forming a spiral, twist drill shaped pointed lower end for penetration into the earth.
Claim 2
Dependent Claim
138 words
A screw anchor for penetration and holding in the earth comprising an elongated shank rotatable about its longitudinal axis and having a lower end portion of polygonal cross-section adapted to penetrate into the earth and a helical flight secured to said lower end portion of said shank for holding engagement in the earth, said helical flight having a diameter substantially greater than the transverse dimension of said shank and having a crowned upper surface extending outwardly of said shank and curved to slope downwardly adjacent the outer edge thereof, said lower end portion including an upper segment above said flight for driving engagement with a tool telescoped thereon, said lower end portion including a lower segment below said flight twisted about said longitudinal axis forming a spiral, twist drill shaped pointed lower end for penetration into the earth.
Claim 3
Dependent Claim
23 words
The screw anchor of claim 1 wherein the axial pitch of said spiral lower segment is approximately equal to that of said flight.
Claim 4
Dependent Claim
29 words
The screw anchor of claim 1 wherein said spiral, twist drill shaped lower segment comprises between one and one half and two turns of twist about said shank axis.
References Cited (Backward Citations)
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Cited
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Cited
US1336773A
Cited
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Cited
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Cited
GB869531A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-25 | 1977-08-27 | 1978-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-25 | 1981-08-27 | 1982-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-25 | 1985-08-27 | 1986-02-26 | $7700.00 | Window Closed / Lapsed |