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US 5,711,512 AGranted
Lifting jack
AssigneeMalcom P. Hammond
InventorLeonard S. Kauffman
Life of this patent
Estimating the term…
Abstract
A lifting jack for raising boats and other objects. It has an inner housing or tube which is supported from a flat base. An outer tube is slidably mounted over the inner tube. A hydraulic jack inside the inner tube raises and lowers the outer tube. Two parallel series of vertical catches are supported on the outside of the outer tube. A selected pair of these catches support a connecting rod which holds a pair of flat support arms in a fixed relationship. The arms support a lifting pad in a plurality of elevations for each pair of vertical catches. A safety latch permits the outer housing to be raised but must be manually released for lowering.
Claims12
A jack assembly comprising:
- a base;
- an outer housing having a front and rear side;
- a height adjusting unit having;
- (i) a first vertical series of support catches supported by the front side of said outer housing;
- (ii) a second vertical series of support catches supported by the front side of said outer housing and spaced from a first series;
- (iii) a first support arm having a front and a rear side with a first series of height adjusting holes along said rear side;
- (iv) a second support arm having a front and a rear side with a second series of height adjusting holes in said rear side;
- (v) a catch positioning support rod connecting said first and second support arms and of a size to fit into support catches of said first and second support catches series;
- (vi) a hole selection rod extending between said first and second support arms and positionable into said series of holes;
- (vii) a lift pad supported from said support arms;
- means to lift said outer housing with respect to said base.
8 more elements
A jack assembly comprising:
- a base;
- an inner tube secured to said base;
- an outer tube having a rear side and a front side and mounted about said inner tube and movable in relation therewith;
- a jack mounted within said inner tube and supported from said base and having an extension shaft;
- means for connecting said jack extension shaft to said outer tube such that lifting said extension shaft lifts said outer tube as said jack extension shaft is extended;
- at least one pair of spaced apart support catches on said outer tube front;
- a height adjusting system including a first support arm and a second support arm each arm having a front end and a rear end and a first support bar connected between said arms and supported in a selected position by said support catches, and a plurality of height adjusting holes in the rear end of each said arm;
- a list pad supported by said support arms;
- and
- a hole selecting rod selectively extendable through said holes to adjust the height of said lift pad.
7 more elements
A jack assembly comprising:
- a base;
- an outer tube;
- a jack means supported from said base and capable of lifting said outer tube;
- a lift pad supported from said outer housing;
- a frame supported from said base for guiding said outer tube as it is raised and lowered, a series of aligned vertical holes in said frame;
- a hole in said outer tube aligned in the same vertical plane with said holes in said frame;
- a pivot supported from said outer tube;
- a safety lever pivotally supported from said pivot and having an engaging finger of a size to enter said hole in said outer tube and an aligned hole in said frame, said safety lever having a center of gravity such that it pivots about said pivot by gravity forcing said finger through said outer tube hole and into said frame hole when the holes are aligned, such that the safety lever will automatically catch when lowering the outer tube and will self-release when the outer tube is raised but is of a structure such that it must be manually released when lowering.
5 more elements
A jack assembly including a lift pad for lifting a load which comprises:
- a base;
- a vertically movable frame having a front and a rear portion;
- a jack for moving said frame vertically and with respect to said base;
- at least one series of vertical catches mounted on the front portion of said frame;
- a height adjusting system including:
- a first support arm and a spaced apart second support arm,
- a support red fixed to each said support arm and insertable into one of said catches on the front of said frame,
- a plurality of height adjusting holes in each said support arm,
- a hole selecting rod extendable through said holes, said rod contacting the rear of said frame upon sufficient rotation of said arms about said support rod,
- means connecting a part of the front end of said support arms to said lift pad.
7 more elements
Dependencies are inferred from the claim text.