Extendible tower structure

Claim 1

An extendible tower structure comprising: a. a base; b. a hydraulic fluid reservoir secured to said base; c. a plurality of nestable tower sections received on said base, a largest of said sections being secured to said base, each adjacent section having means received thereon to engage and raise the next adjacent smallest section; d. a plurality of nestable hydraulic cylinders received within said tower sections, a largest of said cylinders being permanently secured to the smallest tower section and the smallest of said cylinders being permanently secured to said base and in communication with said hydraulic fluid reservoir, said smallest cylinder and each intermediate cylinder having a piston located thereon, said pistons having sealing rings therearound and producing a seal along the inside wall of the next adjacent larger cylinder, each piston having a fluid port therein, and each cylinder engaging the next adjacent smallest cylinder and raising same during raising of the tower; and e. means to controllably supply hydraulic fluid under pressure into said smallest cylinder, said fluid passing through said cylinders to said largest cylinder, and raising said cylinder one at a time, whereby said tower is raised thereby.