Hydraulic lift jack

Claim 2

A hydraulic lift jack comprising: a. a base member, b. a cylinder secured to and projected upwardly from said base member, c. an upright fluid-carrying member with a fluid opening at each end thereof secured to said base member and projected axially upwardly through said cylinder, d. a lift assembly including a pair of circular inner and outer sleeve members concentrically arranged relative to said fluidcarrying member with the inner member within the cylinder and the outer member positioned about and in guidable engagement with said cylinder, e. a piston member for said cylinder secured to the lower end of said inner sleeve member with said fluid-carrying member slidably extended therethrough, f. a closure means for the upper end of said cylinder having a circular slot therein for slidably receiving therethrough the sidewall of the inner sleeve member, g. a source of fluid under pressure, and h. means for supplying the fluid from said source to the underside of said piston member concurrently with the exhaust of fluid from said inner sleeve member downwardly through said fluid-carrying member, when said lift assembly is to be elevated, and for supplying fluid from said source upwardly through said fluid-carrying member and into said inner sleeve member to the upper side of that portion of the piston member defined by the cross-sectional area of the inner sleeve member concurrently with the exhaust of fluid from the underside of the piston member, when said lift assembly is to be lowered.

Claim 3

A hydraulic jack comprising: a. a base member, b. a cylinder secured to and projected upwardly from said base member, c. a piston assembly for said cylinder including a tubular piston rod and a piston member secured to the lower end of said piston rod, d. a lift member guidably mounted about said cylinder for relative longitudinal and rotatable movement, e. means connecting together said lift member and piston rod for unitary movement, f. a closure means for the upper end of said cylinder member having a circular slot therein for slidably receiving therethrough the sidewall of said piston rod, g. an upright fluid carrying member secured to said base member axially of said cylinder member and slidably extended through said piston member and into said piston rod for attachment of the upper end thereof to said closure means, said fluid carrying member having a fluid opening at each end thereof, h. a source of fluid under pressure, and i. means for supplying fluid from said source into the lower end of said cylinder for application against the lower side of said piston member concurrently with the exhaust of fluid from within the piston rod downwardly through said fluid-carrying member, when said lift member is to be elevated, and for supplying fluid from said source upwardly through said fluid-carrying member and into said piston rod for application against the upper side of that portion of the piston member defined by the cross-sectional area of the piston rod concurrently with the exhaust of fluid from the lower end of the cylinder, when said lift member is to be lowered.

Claim 4

A hydraulic jack comprising: a. a base member, b. a cylinder secured to and projected upwardly from said base member, c. a piston assembly for said cylinder including a tubular piston rod and a piston member secured to the lower end of said piston rod, d. a lift member guidably mounted about said cylinder for relative longitudinal and rotatable movement, e. means connecting together said lift member and piston rod for unitary movement, f. a closure means for the upper end of said cylinder member having a circular slot therein for slidably receiving therethrough the sidewall of said piston rod, g. an upright fluid carrying member secured to said base member axially of said cylinder member and slidably extended through said piston member and into said piston rod for attachment of the upper end thereof to said closure means, said fluid carrying member having a fluid opening at each end thereof, h. a source of fluid under pressure, and i. means for supplying fluid from said source into the lower end of said cylinder for application against the lower side of said piston member concurrently with the exhaust of fluid from within the piston rod downwardly through said fluid-carrying member, when said lift member is to be elevated, and for supplying fluid from said source upwardly through said fluid-carrying member and into said piston rod for application against the upper side of that portion of the piston member defined by the cross-sectional area of the piston rod concurrently with the exhaust of fluid from the lower end of the cylinder, when said lift member is to be lowered.

Claim 5

The hydraulic jack according to claim 2 wherein: a. said closure means includes a central circular portion secured to said fluid-carrying member having an outer peripheral surface in slidable engagement with the inner peripheral surface of the sidewall of said piston rod, and an annular portion secured to said cylinder having an inner peripheral surface in slidable engagement with the outer peripheral surface of the sidewall of said piston rod.

Claim 6

A hydraulic jack comprising: a. a base member, b. a cylinder projected upwardly from said base member, c. a piston assembly including a pair of concentrically arranged inner and outer sleeve members, said outer sleeve member mounted about and in bearing engagement with said cylinder member and said inner sleeve member located in a concentrically spaced relation within said cylinder member, d. means connecting said sleeve members at the upper ends thereof for unitary longitudinal and rotatable movement relative to said cylinder, e. closure means for the upper end of said cylinder having portions in slidable engagement with inner and outer surfaces of the sidewall of said inner sleeve member, f. a piston member for said cylinder secured to the lower end of said inner sleeve member, said piston member having a central opening therein, g. a fluid manifold secured to said base member and projected axially of said cylinder upwardly through the central opening in said piston member and into said inner sleeve member for attachment to one of said portions of said closure means, said fluid manifold having a fluid opening at each end thereof, h. a first fluid supply and exhaust line connected to the lower end of said cylinder member, i. a second fluid supply and exhaust line connected with the opening at the lower end of said manifold, and j. a source of fluid under pressure, k. means for selectively controlling the supply of fluid to and the exhaust of fluid from said first and second fluid lines, whereby said piston assembly is elevated when fluid under pressure from said first line is applied against the underside of said piston member concurrently with the exhaust of fluid from within said inner sleeve member downwardly of said manifold and through said second fluid line, and is lowered when fluid under pressure from said second line is directed upwardly of said manifold and into said inner sleeve member to act against the upper side of only that portion of the piston member which closes the lower end of the inner sleeve member, concurrently with the exhaust from the lower end of said cylinder through said first fluid line.

Claim 7

A hydraulic jack comprising: a. a base member, b. a cylinder projected upwardly from said base member, c. a piston assembly including a pair of concentrically arranged inner and outer sleeve members, said outer sleeve member mounted about and in bearing engagement with said cylinder member and said inner sleeve member located in a concentrically spaced relation within said cylinder member, d. means connecting said sleeve members at the upper ends thereof for unitary longitudinal and rotatable movement relative to said cylinder, e. closure means for the upper end of said cylinder having portions in slidable engagement with inner and outer surfaces of the sidewall of said inner sleeve member, f. a piston member for said cylinder secured to the lower end of said inner sleeve member, said piston member having a central opening therein, g. a fluid manifold secured to said base member and projected axially of said cylinder upwardly through the central opening in said piston member and into said inner sleeve member for attachment to one of said portions of said closure means, said fluid manifold having a fluid opening at each end thereof, h. a first fluid supply and exhaust line connected to the lower end of said cylinder member, i. a second fluid supply and exhaust line connected with the opening at the lower end of said manifold, and j. a source of fluid under pressure, k. means for selectively controlling the supply of fluid to and the exhaust of fluid from said first and second fluid lines, whereby said piston assembly is elevated when fluid under pressure from said first line is applied against the underside of said piston member concurrently with the exhaust of fluid from within said inner sleeve member downwardly of said manifold and through said second fluid line, and is lowered when fluid under pressure from said second line is directed upwardly of said manifold and into said inner sleeve member to act against the upper side of only that portion of the piston member which closes the lower end of the inner sleeve member, concurrently with the exhaust from the lower end of said cylinder through said first fluid line.