High rise transmission jack

Claim 2

In a high rise lifting jack for raising a load relative to a supporting surface: a housing member having a base assembly at one end thereof adapted to engage said supporting surface; hydraulic and pneumatic operated members each having inner ends received within said housing for defining spaced, variable volume, hydraulic and pneumatic fluid chambers, said hydraulic and pneumatic operated members being shiftable in combination relative to said housing in response to delivery of pneumatic motive flow to said pneumatic chamber, said hydraulic member being supported by said pneumatic member for shifting individually relative to said housing and said pneumatic member in response to delivery of hydraulic motive flow to said hydraulic chamber, said hydraulic member having a load-carrying head at the outer end thereof adapted to engage said load; pneumatic control means located on said housing member and operatively coupled with said pneumatic chamber for controlling pneumatic motive flow thereto; and hydraulic control means located adjacent said load-carrying head and operatively coupled with said hydraulic chamber for controlling hydraulic motive flow thereto.

Claim 3

A jack as set forth in claim 1, there being locking means for selectively intersecuring said housing and said pneumatic member, whereby to provide solid support structure for said load-carrying head and said hydraulic member during said individual shifting of the hydraulic member.

Claim 4

A jack as set forth in claim 2, wherein said locking means is releasable to permit combined retraction of sAid hydraulic and pneumatic members relative to said housing.

Claim 5

A jack as set forth in claim 3, wherein said pneumatic control means includes a retraction control element secured to the housing member and operably connected with said pneumatic chamber, said retraction control element being shiftable to a release position to permit exhaust flow from said pneumatic chamber and thereby permit said combined retraction of said hydraulic and pneumatic members when said locking means is released.

Claim 6

A jack as set forth in claim 4, wherein said pneumatic control means also includes an extension control element secured to the housing member and operably connected with said pneumatic chamber, said extension control element being shiftable to a position for directing pneumatic motive inlet flow to said pneumatic chamber to effect combined extension of both said pneumatic and hydraulic members relative to said housing.

Claim 7

A jack as set forth in claim 4, wherein said locking means includes a pawl, said pawl being interengageable with said housing and said pneumatic member upon shifting of the latter to its outermost, extended position relative to said housing, whereby to intersecure said housing and said pneumatic member in said outermost position.

Claim 8

A jack as set forth in claim 6, wherein said locking means also includes a link extending between and operatively engaging said pawl and said retraction control element, said link being operable to release said pawl in response to shifting of said retraction control element to said release position, whereby to permit said combined retraction of the hydraulic and pneumatic members.

Claim 9

A jack as set forth in claim 1, said head being shiftably secured to said hydraulic member and presenting a lifting surface adapted to engage the load.

Claim 10

A jack as set forth in claim 8, wherein said hydraulic control means includes a motive fluid supply pump carried by said head and operatively connected with said hydraulic chamber for delivering hydraulic motive flow thereto when operated to effect individual extension of said hydraulic member from said pneumatic member.

Claim 11

A jack as set forth in claim 9, wherein said hydraulic control means further includes a release valve operatively carried by said head and operatively connected with said hydraulic chamber, said release valve being shiftable to a clearing position to permit exhaust flow from said hydraulic chamber and thereby permit individual retraction of said hydraulic member into said pneumatic member.

Claim 12

A jack as set forth in claim 2, wherein said pneumatic member includes a first, hollow cylinder having an inner end disposed in the interior of said housing member; and first piston means secured to said inner end of the first cylinder and positioned in sealing relationship with said housing member for defining said pneumatic chamber within the interior of said housing.

Claim 13

A jack as set forth in claim 11, wherein is provided a ledge on the external surface of said first cylinder, and wherein said locking means includes a pawl movably mounted upon said housing member and normally disposed to engage said ledge upon positioning of said first cylinder in its outermost, extended position whereby to thereupon prevent retraction of said first cylinder into said housing, said pawl being selectively movable away from said ledge to permit said combined retraction of the hydraulic and pneumatic members.

Claim 14

A jack as set forth in claim 12, wherein is provided a ram extending from said hydraulic chamber into engagement with said first piston means whereby to support said load-carrying head and said hydraulic member upon said first cylinder during said individual shifting of the hydraulic member.

Claim 15

A jack as set forth in claim 13, wherein said hydraulic member includes a second, hollow cylinder having an inner end received within the interior of said first cylinder and an outer end operatively secured to said head.

Claim 16

A jack as set forth in claim 14, wherein said hydraulic membeR further includes second piston means secured to said inner end of the second cylinder and positioned in sealing relationship with said ram for defining said hydraulic chamber within the interior of said second cylinder between said outer end thereof and said second piston means.

Claim 17

A jack as set forth in claim 15, wherein said hydraulic member further includes a third, hollow cylinder disposed intermediate said first and second cylinders and having an inner end secured to said second piston means and an outer end operatively secured to said head, whereby to define an annular, fluid reservoir chamber between said second and third cylinders.

Claim 18

A jack as set forth in claim 16, wherein said hydraulic control means is operably connected with said annular reservoir chamber for controlling hydraulic flow between the latter and said hydraulic chamber.

Claim 19

In a high rise lifting jack for shifting a load relative to a ground support surface: a stand comprising first and second members positioned in a telescoping relationship and defining a pneumatic fluid chamber therebetween, said first and second members being relatively reciprocable in response to delivery of pneumatic motive flow to said pneumatic chamber; locking means for intersecuring said first and second members upon locating same in a predetermined, relative position to prevent relative reciprocation therebetween; a third member positioned in telescoping relationship with said second member, said third member defining a hydraulic fluid chamber, said third member and said stand being relatively reciprocable in response to delivery of hydraulic motive flow to said hydraulic chamber; support stations disposed at opposite, remote ends of said first and third members whereby to reciprocate relatively in response both to delivery of said pneumatic flow and said hydraulic flow, one of said support stations being adapted to engage said ground support surface and the other being adapted to engage said load; pneumatic control means positioned at said support station associated with said first member and operably connected with said pneumatic chamber for controlling pneumatic motive flow thereto; and hydraulic control means positioned at said support station associated with said third member and operably connected with said hydraulic chamber for controlling hydraulic motive flow thereto.

Claim 20

In a high rise lifting jack for shifting a load relative to a ground support surface: a stand comprising first and second members positioned in a telescoping relationship and defining a pneumatic fluid chamber therebetween, said first and second members being relatively reciprocable in response to delivery of pneumatic motive flow to said pneumatic chamber; locking means for intersecuring said first and second members upon locating same in a predetermined, relative position to prevent relative reciprocation therebetween; a third member positioned in telescoping relationship with said second member, said third member defining a hydraulic fluid chamber, said third member and said stand being relatively reciprocable in response to delivery of hydraulic motive flow to said hydraulic chamber; support stations disposed at opposite, remote ends of said first and third members whereby to reciprocate relatively in response both to delivery of said pneumatic flow and said hydraulic flow, one of said support stations being adapted to engage said ground support surface and the other being adapted to engage said load; pneumatic control means positioned at said support station associated with said first member and operably connected with said pneumatic chamber for controlling pneumatic motive flow thereto; and hydraulic control means positioned at said support station associated with said third member and operably connected with said hydraulic chamber for controlling hydraulic motive flow thereto.