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US 4,657,233 AGranted
Assist apparatus for ramps
OwnerJames W. Vroominventor
Life of this patent
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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.
Claims6
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.
4 more elements
Dependencies are inferred from the claim text.