Lift truck mast assembly
United States Patent 3394778

1,178,867. Masted lift trucks. EATON YALE & TOWNE Inc. 12 June, 1967 [25 Nov., 1966], No. 26977/67. Heading B8H. A lift truck telescopic mast comprises a pair of fixed lower uprights 10, pairs of vertically movable uprights 13, 14, 15 and a lift ram 42 adjacent each upright 10 and having the upper end of its cylinder mounted at the upper end of the upright 10 so that the ram is suspended therefrom. The rams 42 are mounted on a U- shaped flange 12 connecting the upper ends of the fixed uprights 10 and the ram piston-rods 44 engage a bracing member 50 connecting the upper ends of the secondary uprights 13 to elevate the latter upon extension of the rams 42. The tertiary uprights 14 are elevated at twice the speed of the secondary uprights 13 by use of a pair of chains 55 which each have their ends anchored to the flange 12 and the bottom of the uprights 14, the therebetween pass over a sprocket 56 on the secondary uprights 13. The fourth pair of uprights 15, which carry a load carriage 21, are similarly elevated at twice the speed of the uprights 14. The load carriage 21 is elevated relative to the uprights 15, by a ram 24 and chains 32 which are anchored to the carriage 21 and to the bottom of the uprights 15, and are engaged intermediate their points by a pair of sprockets on the piston-rod of the ram 24. The carriage ram 24 and the lift rams 42 are both single acting and are operated by the same fluid system, the ram 24 operating at a lower pressure than the rams 42 so that the carriage 21 is elevated on the uprights 15 before the uprights are elevated relative to each other.

Brinton, Caleb J.
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187/226, 187/234
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