Extensible lifting tower with hydraulic cylinders in series

A lifting tower comprising:

• a base, an extensible stabilizing tower, a base hydraulic lifting means, and an upper hydraulic lifting means, said extensible stabilizing tower comprising a base stage, at least one intermediate stage and an upper supporting stage, each of said stages having a vertical rigid member, the lower end of said base stage being secured to said base, the rigid member of each stage overlapping an adjacent one of said stages, guiding means between adjacent ones of said overlapping rigid members for allowing only vertical travel above and into said base stage, means for connecting said base hydraulic lifting means upright between said base and the upper end of said upper supporting stage, a header for contacting a load connected to the top of said upper hydraulic lifting means, a platform secured to the bottom of said upper supporting stage, means for securing the lower end of said upper hydraulic lifting means to said platform, said base hydraulic lifting means being operative to extend said extensible stabilizing tower, and said upper hydraulic means being operative subsequently to lift said header to a level substantially higher than the highest level of the upper end of said base hydraulic lifting means.