Multi-stage lift

Claim 2

A portable hoisting device comprising; a base assembly having ground support wheels collectively defining a first ground support contact plane, a plurality of outrigger mounting means spaced about the periphery of said base assembly, a plurality of outriggers operatively associated with said mounting means and having ground support wheels near their outer ends collectively defining a second ground support contact plane lower than said first plane when the outriggers are in operative position whereby said wheels on the base assembly are raised out of ground contact when the outriggers are in operation, said outriggers being adapted to be selectively moved out of said operative position to move their ground support wheels above said first plane whereby the hoisting device is then supported by the ground supporT wheels of the base assembly, a hoist assembly mounted on the base assembly, and a work platform carried by the hoist assembly to be raised and lowered thereby.

Claim 3

A portable hoisting device according to claim 1 in which leveling jack means are selectively operatively associated with the outer end portions of said outriggers.

Claim 4

A portable hoisting device according to claim 1 in which jack means are operatively associated with opposite sides of said base asembly for selectively raising the respective side to a height whereat adjacent outriggers can be placed in operative position.

Claim 5

A lift device according to claim 3 in which said guard rail assembly includes top guard rails fixed to the upper ends of said posts and arranged to rest on said intermediate guard rails when the posts are in lowered storage position.

Claim 6

A portable hoisting device according to claim 1 in which said mounting means comprises elongated slide sockets and said outriggers are adapted to be slidably plugged into said sockets.

Claim 7

A portable hoisting device according to claim 1 in which said base assembly is generally rectangular in plan view and said mounting means comprises four elongated slide sockets extending in generally diagonal directions inwardly from the corners of the base assembly, and in which said outriggers are adapted to be slidably plugged into said sockets.

Claim 8

A portable hoisting device according to claim 6 in which a pair of elongated slide sockets are located at one end of said base assembly and extend in opposite lateral directions whereby said one end can be placed against a wall or obstruction with the outriggers at that end fitted in said pair of sockets rather than in the diagonal sockets at that end.

Claim 9

A portable hoisting device comprising, a hand truck including a ladder with handles near the top thereof and ground support wheels near the bottom thereof providing ground support when the hand truck is tilted rearwardly, a base frame assembly supported at the forward side of the hand truck and having ground support means arranged to be raised from ground contact when the hand truck is tilted rearwardly, three upright multi-stage gas-operated telescopic cylinder hoists mounted on the base frame assembly in a triangular arrangement in plan view with two of said hoists located adjacent opposite lateral sides of the hand truck and having their bottom stages partly braced by the ladder and with the third hoist spaced directly forward from the lateral center of the hand truck and having its bottom stage rigidly interconnected with the bottom stages of said two hoists, a work platform carried by said three hoists to be raised and lowered thereby, said platform having a lowered position adjacent the top of said ladder when the hoists are retracted, means for selectively extending and retracting said hoists in unison, and a plurality of outrigger means spaced about the periphery of the base frame assembly and arranged to be selectively moved into and out of ground engaging position.

Claim 10

A portable hoisting device comprising, a hand truck including a ladder with handles near the top thereof and ground support wheels near the bottom thereof providing ground support when the hand truck is tilted rearwardly, a base frame assembly supported at the forward side of the hand truck and having ground support means arranged to be raised from ground contact when the hand truck is tilted rearwardly, three upright multi-stage gas-operated telescopic cylinder hoists mounted on the base frame assembly in a triangular arrangement in plan view with two of said hoists located adjacent opposite lateral sides of the hand truck and having their bottom stages partly braced by the ladder and with the third hoist spaced directly forward from the lateral center of the hand truck and having its bottom stage rigidly interconnected with the bottom stages of said two hoists, a work platform carried by said three hoists to be raised and lowered thereby, said platform having a lowered position adjacent the top of said ladder when the hoists are retracted, means for selectively extending and retracting said hoists in unison, and a plurality of outrigger means spaced about the periphery of the base frame assembly and arranged to be selectively moved into and out of ground engaging position.

Claim 11

A portable hoisting device according to claim 8 in which said three hoists each have a plurality of telescopic stages intermediate a bottom stationary stage mounted on the base frame assembly and a top stage connected to the work platform, said means for selectively extending and retracting said hoists in unison comprising respective horizontal coplanar brace means interconnecting the upper end of the three cylinders of each said intermediate stage, said horizontal brace means being the sole means interconnecting said intermediate stages between the top of the bottom stationary stage and the work platform.

Claim 12

A portable hoisting device according to claim 8 in which said outrigger means have ground support wheels near their outer ends which take the entire load of the hoisting device when such wheels are in ground engaging position.

Claim 13

A portable hoisting device comprising, a portable base assembly, three upright parallel multi-stage gas-operated telescopic cylinder hoist units in equally spaced relationship from one another and having their bottom stages rigidly interconnected and mounted on the base assembly, a work platform mounted on the top stages of the hoist units, said hoists each having a respective plurality of telescopic cylinder stages intermediate said bottom stages and said work platform, said intermediate stages and said top stages being arranged and adapted to be extended solely by compressed gas, a respective collar on the upper end of each such intermediate cylinder stage, respective brace means at each intermediate stage interconnecting the respective collars, said brace means for the intermediate stages being arranged to stack between the bottom stages and the working platform when the hoisting device is in lowered position and to provide the bracing for the intermediate stages when the hoisting device is in raised position, the brace means for each intermediate stage comprises three braces arranged generally in an equilateral triangle in plan view with each such brace having two longitudinal overlapping parts and means for fastening said overlapping parts together whereby the overall length of said braces can be set during assembly so that the brace means will not exert lateral forces on the intermediate cylinder stages when they are extended without the work platform being loaded.

Claim 14

A portable hoisting device comprising, a portable base assembly, three upright parallel multi-stage gas-operated telescopic cylinder hoist units in equally spaced relationship from one another and having their bottom stages rigidly interconnected and mounted on the base assembly, a work platform mounted on the top stages of the hoist units, said hoists each having a respective plurality of telescopic cylinder stages intermediate said bottom stages and said work platform, said intermediate stages and said top stages being arranged and adapted to be extended solely by compressed gas, a respective collar on the upper end of each such intermediate cylinder stage, respective brace means at each intermediate stage interconnecting the respective collars, said brace means for the intermediate stages being arranged to stack between the bottom stages and the working platform when the hoisting device is in lowered position and to provide the bracing for the intermediate stages when the hoisting device is in raised position, the brace means for each intermediate stage comprises three braces arranged generally in an equilateral triangle in plan view with each such brace having two longitudinal overlapping parts and means for fastening said overlapping parts together whereby the overall length of said braces can be set during assembly so that the brace means will not exert lateral forces on the intermediate cylinder stages when they are extended without the work platform being loaded.

Claim 15

A portable hoisting device according to claim 11 in which said three telescopic cylinder hoist units have their extending cylinders formed of lightweight thin-walled tubing on the upper end of which the respective collar is mounted, said braces providing the sole lateral support for said intermediate stages between their telescopic connections with the top and bottom stages.

Claim 16

A portable hoisting device comprising a portable base assembly including a base frame of generally rectangular outline in plan view having four slide socket members extending inwardly in generally diagonal directions from open outer ends at the corners of the base frame and having frame members rigidly interconnecting said socket members adjacent their said open ends, said socket members also being rigidly interconnected in inwardly spaced relation from said frame members for giving added support to the socket members and contributing to rigidity of the base frame, four elongated outriggers adapted to be slidably plugged into the open ends of said socket members, an upright hoist assembly mounted on the base frame, a work platform carried by the hoist assembly to be raised and lowered thereby, and ground support wheels on the base assembly for transporting the hoisting device when the outriggers are not plugged into the socket members.

Claim 17

A portable hoisting device comprising a portable base assembly including a base frame of generally rectangular outline in plan view having four slide socket members extending inwardly in generally diagonal directions from open outer ends at the corners of the base frame and having frame members rigidly interconnecting said socket members adjacent their said open ends, said socket members also being rigidly interconnected in inwardly spaced relation from said frame members for giving added support to the socket members and contributing to rigidity of the base frame, four elongated outriggers adapted to be slidably plugged into the open ends of said socket members, an upright hoist assembly mounted on the base frame, a work platform carried by the hoist assembly to be raised and lowered thereby, and ground support wheels on the base assembly for transporting the hoisting device when the outriggers are not plugged into the socket members.

Claim 18

A portable hoisting device comprising, a base assembly presenting a plurality of outwardly opening slide sockets spaced about its periphery and having transport wheels, a hoist assembly mounted on the base assembly, a work platform carried by the hoist assembly to be raised and lowered thereby, and a plurality of outriggers adapted to be slidably plugged into said sockets, said base assembly having a plurality of ground support means collectively defining a first ground support contact plane, and said outriggers having ground support wheels near their outer ends collectively defining a second ground support contact plane lower than said first plane when the outriggers are in operative position whereby said ground wheels support means on the base assembly are raised out of ground contact when the outriggers are in operation.

Claim 19

A portable hoisting device comprising, a base assembly presenting a plurality of outwardly opening slide sockets spaced about its periphery and having transport wheels, a hoist assembly mounted on the base assembly, a work platform carried by the hoist assembly to be raised and lowered thereby, and a plurality of outriggers adapted to be slidably plugged into said sockets, said base assembly having a plurality of ground support means collectively defining a first ground support contact plane, and said outriggers having ground support wheels near their outer ends collectively defining a second ground support contact plane lower than said first plane when the outriggers are in operative position whereby said ground wheels support means on the base assembly are raised out of ground contact when the outriggers are in operation.

Claim 20

A hoisting device according to claim 14 in which said base assembly has jack means for selectively raising the sockets of said base assembly and said ground support means sufficiently to permit the outriggers to be installed.

Claim 21

A hoisting device according to claim 14 in which said base assembly has a generally rectangular frame in plan view and four of said slide sockets extend inwardly in generally diagOnal directions from the corners of the frame.

Claim 22

A hoisting device according to claim 16 in which a pair of slide sockets are located at one end of said frame and extend in opposite lateral directions whereby said one end can be placed against a wall or obstruction with outriggers at the end fitted in said pair of sockets rather than in the diagonal sockets at that end.

Claim 23

A hoisting device according to claim 14 in which said base assembly has a generally rectangular frame in plan view and in which said hoist assembly comprises, three multi-stage fluid-operated cylinders which rest, two on adjoining corners of the frame and the third at the center of the side of the frame opposite from said adjoining corners, and in which said work platform is also generally rectangular and has approximately the same horizontal extent and orientation as said frame.

Claim 24

A hoisting device according to claim 18 in which said work platform has corner posts slidably mounted to project downwardly and be outwardly of said hoist assembly when in a storage position and to project upwardly when in an operating position, and guard rails mounted on the corner posts.

Claim 25

A portable hoisting device comprising, a carriage, a hoist assembly mounted on the carriage, a work platform carried by the hoist assembly to be selectively raised and lowered thereby between retracted and extended positions, a ladder supported by the carriage and extending to the work platform when the hoist assembly is in retracted position, handle grips near the top of the ladder, a pair of ground support wheels adjacent the foot of the ladder whereby the hoisting device can be handled like a hand truck by use of said wheels and handle grips, said carriage having a pair of horizontal slide sockets diverging on opposite sides of said ladder outwardly of said pair of wheels and having a pair of horizontal slide sockets at the opposite end of the carriage from the ladder, and four outriggers adapted to be slidably plugged into said pairs of sockets and provide the ground support for the carriage.

Claim 26

A portable hoisting device comprising, a carriage, a hoist assembly mounted on the carriage, a work platform carried by the hoist assembly to be selectively raised and lowered thereby between retracted and extended positions, a ladder supported by the carriage and extending to the work platform when the hoist assembly is in retracted position, handle grips near the top of the ladder, a pair of ground support wheels adjacent the foot of the ladder whereby the hoisting device can be handled like a hand truck by use of said wheels and handle grips, said carriage having a pair of horizontal slide sockets diverging on opposite sides of said ladder outwardly of said pair of wheels and having a pair of horizontal slide sockets at the opposite end of the carriage from the ladder, and four outriggers adapted to be slidably plugged into said pairs of sockets and provide the ground support for the carriage.

Claim 27

A hoisting device according to claim 20 in which said carriage has a pair of jacks located between said pairs of slide sockets.

Claim 28

A hoisting device according to claim 20 in which said outriggers each comprise an elongated tube fitting by one of its ends into a respective said socket and having its opposite end open to form a socket for selectively receiving a leveling jack assembly.

Claim 29

A portable hoisting device comprising, a base assembly presenting a plurality of horizontally opening slide sockets spaced about its periphery, a hoist assembly mounted in the base assembly, a work platform carried by the hoist assembly to be raised and lowered thereby, and a plurality of outriggers adapted to be plugged into said sockets, said base assembly having a generally rectangular frame in plan view with one end of said frame having a pair of oppositely extending lateral slide sockets for outriggers and the four corners of the frame having diagonally extending slide sockets for outriggers, said hoist assembly comprising three multi-stage fluid-operated cylinders which rest, two on adjoining corners of the frame opposite from said adjoining corners, and said work platform also being generally rectangular and having approximately the same horizontal extent and orientation as said frame.

Claim 30

A portable hoisting device comprising, a base assembly presenting a plurality of horizontally opening slide sockets spaced about its periphery, a hoist assembly mounted in the base assembly, a work platform carried by the hoist assembly to be raised and lowered thereby, and a plurality of outriggers adapted to be plugged into said sockets, said base assembly having a generally rectangular frame in plan view with one end of said frame having a pair of oppositely extending lateral slide sockets for outriggers and the four corners of the frame having diagonally extending slide sockets for outriggers, said hoist assembly comprising three multi-stage fluid-operated cylinders which rest, two on adjoining corners of the frame opposite from said adjoining corners, and said work platform also being generally rectangular and having approximately the same horizontal extent and orientation as said frame.

Claim 31

A lift device comprising a base support, upwardly extending hoisting means on the base support, a work platform mounted on the hoisting means to be raised and lowered thereby, a guard rail assembly on the platform including a plurality of interconnected, spaced posts vertically slidable relative to the platform between the raised, guarding position in which a major longitudinal portion of each post projects above the platform and a storage position in which a major longitudinal portion of each post is suspended below the platform, intermediate guard rails slidably mounted on the Posts, flexible means extending from the top of the posts to said intermediate rails whereby the latter are held at a predetermined height relative to the posts when the posts are in raised, guarding position and rest on the work platform when the posts are in lowered, storage position, and locking means for selectively holding the posts in said guarding position.

Claim 32

A lift device comprising a base support, upwardly extending hoisting means on the base support, a work platform mounted on the hoisting means to be raised and lowered thereby, a guard rail assembly on the platform including a plurality of interconnected, spaced posts vertically slidable relative to the platform between the raised, guarding position in which a major longitudinal portion of each post projects above the platform and a storage position in which a major longitudinal portion of each post is suspended below the platform, intermediate guard rails slidably mounted on the Posts, flexible means extending from the top of the posts to said intermediate rails whereby the latter are held at a predetermined height relative to the posts when the posts are in raised, guarding position and rest on the work platform when the posts are in lowered, storage position, and locking means for selectively holding the posts in said guarding position.