US3876039A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mechanical lift truck
Assignee: Individual
•
Filing: 1973-01-29
•
Granted: 1975-04-08
•
Expires: 1993-01-29
Abstract
Abstract A manually operable material handling and lifting vehicle capable of lifting loads, supporting them during transport and raising them to an elevated position. The vehicle comprises a wheeled base member having a vertical upright, and a first telescoping member extendable to approximately twice the height of the vertical upright, and a carriage slidably secured to the first telescoping member movable the entire vertical distance of the telescoping member whereby when the first telescoping member and the carriage are at their uppermost position the load has been lifted to a position approximately two times the height of the vertical upright. The carriage and first telescoping member are moved by the interaction of a winch and a single cable.
Inventors
- 👤 Jr Sherman W Bushnell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:34
CPC Classifications
B; B66; B66F; B66F9/00; B66F9/06; B66F9/075; B66F9/07559
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
193 words
A portable lift comprising, a portable base including an upwardly projecting first mast frame of generally rectangular configuration, a second mast frame of generally rectangular configuration slidably mounted on said first frame for vertical movement relative thereto. a carriage slidably mounted on said second frame for vertical movement relative thereto and carrying horizontally projecting lifting element means, winch means supported by the base and having a cable wound thereon, sheave means on the top of said first frame, the bottom and top of said second frame, and on said carriage through which said cable is reeved in the recited order and dead-ended on the top of the second frame to provide a mechanical advantage for lifting said second frame relative to the first frame and for also providing a mechanical advantage for lifting said carriage relative to said second frame, said second-mentioned mechanical advantage being as great as the first-mentioned mechanical advantage whereby when the cable is hauled in by the winch means said carriage is raised substantially to its full extent relative to the second frame before said second frame moves upwardly relative to the first frame to further raise the carriage.
Claim 2
Dependent Claim
193 words
A portable lift comprising, a portable base including an upwardly projecting first mast frame of generally rectangular configuration, a second mast frame of generally rectangular configuration slidably mounted on said first frame for vertical movement relative thereto. a carriage slidably mounted on said second frame for vertical movement relative thereto and carrying horizontally projecting lifting element means, winch means supported by the base and having a cable wound thereon, sheave means on the top of said first frame, the bottom and top of said second frame, and on said carriage through which said cable is reeved in the recited order and dead-ended on the top of the second frame to provide a mechanical advantage for lifting said second frame relative to the first frame and for also providing a mechanical advantage for lifting said carriage relative to said second frame, said second-mentioned mechanical advantage being as great as the first-mentioned mechanical advantage whereby when the cable is hauled in by the winch means said carriage is raised substantially to its full extent relative to the second frame before said second frame moves upwardly relative to the first frame to further raise the carriage.
Claim 3
Dependent Claim
21 words
A portable lift according to claim 1 in which said first-mentioned mechanical advantage and second-mentioned advantage are each two to one.
Claim 4
Dependent Claim
91 words
A portable lift according to claim 1 in which said lifting element means comprises a pair of fork elements and said base has a pair of ground support wheels near the lower end of said first frame, and a pair of laterally spaced outriggers projecting from said base between said wheels in the same direction as the fork elements and arranged to have said fork elements located therebetween when the fork elements are in a lowered position, said outriggers being removable and being horizontally adjustable on said base in said direction.
Claim 5
Dependent Claim
75 words
A portable lift according to claim 1 in which each of said fork elements has a support leg extending from its inner end, and means on the carriage for selectively mounting each support leg in alternate vertical positions whereat the fork is in operating position at the bottom of the leg or the top of the leg to thereby provide alternative fork elevations when the carriage is at its uppermost position relative to the base.
Claim 6
Dependent Claim
52 words
A portable lift according to claim 1 in which said first frame is rigidly mounted on said base and has an elevated handle on the opposite side thereof from said lifting element means, and in which said winch means is manually operated and is mounted beneath said handle on said first frame.
Claim 7
Dependent Claim
159 words
A portable lift comprising, a vertical frame assembly, a vertically movable carriage slidably mounted on said frame assembly and having a pair of laterally spaced fork mounting means each comprising a respective horizontal pair of laterally projecting and vertically spaced fork supports, a pair of vertically reversible L-shaped fork elements each having a horizontal lifting fork and a vertical support leg adapted to be alternatively sleeved on the fork elements of a respective said fork mounting means in a first position whereat the fork is at the bottom of the leg or in a second vertically reversed position whereat the fork is at the top of the leg and projects in the same direction as when in said first position whereby the maximum elevation of said lifting forks may be varied by vertically reversing the support legs, and means for moving said carriage to the top of said frame assembly with said lifting forks in either of said positions.
Claim 8
Dependent Claim
159 words
A portable lift comprising, a vertical frame assembly, a vertically movable carriage slidably mounted on said frame assembly and having a pair of laterally spaced fork mounting means each comprising a respective horizontal pair of laterally projecting and vertically spaced fork supports, a pair of vertically reversible L-shaped fork elements each having a horizontal lifting fork and a vertical support leg adapted to be alternatively sleeved on the fork elements of a respective said fork mounting means in a first position whereat the fork is at the bottom of the leg or in a second vertically reversed position whereat the fork is at the top of the leg and projects in the same direction as when in said first position whereby the maximum elevation of said lifting forks may be varied by vertically reversing the support legs, and means for moving said carriage to the top of said frame assembly with said lifting forks in either of said positions.
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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) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |