Patent ID: 8033778

Claim:
An elevating conveyance device comprising a base, a pair of spaced apart right and left vertically extensible multistage columns mounted on said base, an object support, and drive means for extending and contracting said columns, characterized by (a) said multistage columns each having an inner side, facing the other multistage column, and an outer side and including a fixed column mounted on said base, one or more mid-stage elevating columns, and a final stage elevating column, (b) an outermost mid-stage column of each multistage column being movably supported by and externally of the fixed column thereof, on an inner side thereof, (c) each additional mid-stage column of each multistage column being movably supported by an outwardly adjacent mid-stage column externally thereof and on an inner side thereof, (d) said final stage elevating column of each multistage column being movably supported by an innermost one of said one or more mid-stage columns, externally thereof and on an inner side thereof, (e) the respective final stage elevating columns being joined integrally to each other by a horizontal joint member mounting said object support, (f) each multistage column including a counterweight positioned within said fixed column and movable vertically therein within a range corresponding to a height of said fixed column, (g) a flexible element being connecting each counterweight to the outermost mid-stage column to apply the weight of the counterweight as an elevating force upon said outermost mid-stage column, (h) flexible elements being connected to each of said fixed and mid-stage columns, extending over a portion of an intervening mid-stage elevating column next adjacent thereto on the inside thereof, and connected to an elevating column next adjacent to the intervening column on the inside thereof, to effect transfer of vertical movement of said intervening mid-stage elevating column to the column next adjacent thereto on the inside thereof, whereby upward movement of the outermost mid-stage elevating column of a multistage column is transferred to successive adjacent mid-stage elevating columns on the inside thereof, and upward movement of the inwardmost mid-stage elevating column is transferred to said final stage elevating column, (i) said drive means comprising a drive motor associated with the outermost mid-stage elevating column of each multistage column and controllable to raise or lower said outermost mid-stage column, and (j) each of said mid-stage elevating columns and said final stage elevating column having lower limit positions in which lower ends thereof are supported on said base.