PURPOSE: To enable easy and safe imbalance adjustment and to shorten operating time.
CONSTITUTION: A boss portion 3 having a through hole 3a vertically passing therethrough is provided on the upper side of a support bracket 1 erected at the lower end portion of the pair of right and left outer masts (fixed masts), and the lower end of a right lift cylinder 5 is freely slidably fitted into the through hole 3a, and an adjuster 6 is threaded into the through hole 3a from below to support the lower end of the right lift cylinder 5. Imbalance adjustment is carried out by vertically moving the right lift cylinder 5 by rotation of the adjuster 6 to either right or left with an inner mast lifted to the maximum lift by the right and left lift cylinders 4, 5.
TAKAGI TERUO
WATANABE OSAMU
