Patent US5887715A successfully refreshed from Google Patents.
US4657233A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Assist apparatus for ramps
Assignee: Individual
•
Filing: 1985-04-19
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Granted: 1987-04-14
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Expires: 2005-04-19
Abstract
Abstract A coil spring, mounted within a cylinder and axially coincident with the pivot axis between a trailer and a ramp pivotally attached thereto, exerts a force angularly proportional to angular deviation of the ramp from its upright position to reduce the apparent weight of the ramp during manual repositioning of the ramp.
Inventors
- 👤 James W. Vroom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 21:12
CPC Classifications
B; B60; B60P; B60P1/00; B60P1/43; B60P1/438
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
174 words
A spring assist mechanism for assisting pivotal movement intermediate two elements, such as a ramp extending from a trailer, said mechanism comprising in combination: (a) a coil spring having opposed ends for exerting a material force to assist pivotal movement of the ramp relative to the trailer; (b) a shaft located internally concentric with said coil spring for translating a force exerted by said coil spring to the trailer; (c) a shroud enveloping said coil spring for translating a force exerted by said coil spring to the ramp; (d) means for securing one end of said coil spring to said shaft; and (e) further means for securing the other end of said coil spring to said shroud, said further securing means comprising a further annular bearing in penetrable engagement with said shaft and disposed within said shroud and further means for fixedly attaching said further annular bearing to said shroud; whereby, the degree of assisting force produced by said mechanism is a function of the relative pivotal relationship between the ramp and the trailer.
Claim 2
Dependent Claim
174 words
A spring assist mechanism for assisting pivotal movement intermediate two elements, such as a ramp extending from a trailer, said mechanism comprising in combination: (a) a coil spring having opposed ends for exerting a material force to assist pivotal movement of the ramp relative to the trailer; (b) a shaft located internally concentric with said coil spring for translating a force exerted by said coil spring to the trailer; (c) a shroud enveloping said coil spring for translating a force exerted by said coil spring to the ramp; (d) means for securing one end of said coil spring to said shaft; and (e) further means for securing the other end of said coil spring to said shroud, said further securing means comprising a further annular bearing in penetrable engagement with said shaft and disposed within said shroud and further means for fixedly attaching said further annular bearing to said shroud; whereby, the degree of assisting force produced by said mechanism is a function of the relative pivotal relationship between the ramp and the trailer.
Claim 3
Dependent Claim
38 words
The mechanism as set forth in claim 1 wherein said securing means comprises an annular bearing in penetrable engagement with said shaft and disposed within said shroud and means for fixedly attaching said annular bearing to said shaft.
Claim 4
Dependent Claim
20 words
The mechanism as set forth in claim 2 including means for lubricating said annular bearing and said further annular bearing.
Claim 5
Dependent Claim
26 words
The mechanism as set forth in claim 2 including tab means for retaining opposed ends of said shaft, said tab means being securable to the trailer.
Claim 6
Dependent Claim
18 words
The mechanism as set forth in claim 4 including weld means for attaching said shroud to the ramp.
Claim 7
Dependent Claim
15 words
The mechanism as set forth in claim 1 including means for pre-loading said coil spring.
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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) | 1990-04-13 | 1990-10-13 | 1991-04-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-13 | 1994-10-13 | 1995-04-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-13 | 1998-10-13 | 1999-04-14 | $7700.00 | Window Closed / Lapsed |