PURPOSE: To eliminate the need for a ground crane so as to facilitate hoisting of materials and to reduce construction period by inserting pins into pin holes in a mast from upper and lower beams which are secured respectively to a hydraulic cylinder main body and a piston rod.
CONSTITUTION: An upper circular beam 10 is secured to the lower surface of a crane part 5 and a pin is inserted from the pin cylinder of a lower circular beam 8 into that pin hole 6 of a mast 3 which coincides with the pin cylinder. Next, the pin is pulled out of the pin hole 6 by control of the pin cylinder of the upper beam 10, and a piston rod 9 is expanded to its maximum length by a hydraulic cylinder 7. Then the pin is inserted into the pin hole 6 from the pin cylinder of the upper beam 10, and the upper beam 10 and the crane part 5 are raised to insert the pin into the corresponding pin hole 6 of the mast 3. For the lower beam 8, similar operations are carried out to push the lower beam 8 down to insert a pin into the pin hole 6 of the mast 3. The operations are repeated so as to freely raise and lower a crane relative to the mast 3.
TAKAHASHI MASASHI
ODA YASUHIRO
YAMAKAGE HISANAO
KANEKAWA TAKEO
