L46A1 Mast Section The function of tower crane lifting height limiter and slewing limiter
Lifting height limiter:
The lifting height limiter is used to avoid possible control errors. In order to avoid damage to the crane boom structure during lifting and prevent the steel wire rope on the drum from completely loosening or even surrounding the drum in the opposite direction during lowering.
For the tower crane with boom type luffing, the lifting height limiter is generally composed of bumper, lever, spring and travel switch, and is mostly fixed at the end of the boom. The heavy hammer is connected with the lever of the end switch through the steel wire rope of the shackle and the limiter. When the hammer is in the abnormal position, the contact of the end switch is closed. If the hook picks up, drags the heavy hammer and continues to rise slightly to get rid of the gravity effect of the heavy hammer, the lever of the end switch will move an angle under the action of the spring, so that the contact of the control circuit of the lifting mechanism is disconnected and the hook rises to a standstill.
For the self elevating tower crane with trolley luffing degree boom, the lifting height limiter is installed at the drum shaft end of the lifting mechanism. The multi-function limiter is composed of a transmission system (deceleration installation) and a travel switch. The limiter installed at one end of the drum is directly driven by the drum, and it can also be driven by the combination of the gear ring fixed on the drum and the small gear teeth.
Swing stop:
The most commonly used slewing limiter is composed of a limit switch with a reduction device and a pinion. The limiter is fixed on the upper slewing support structure of the tower crane, and the pinion is toothed with the big gear of the slewing bearing.
When the upper part of the tower crane is moved by the electric drive of the slewing folding structure, the small gear of the slewing limiter is driven to roll by the big gear ring, the number of slewing rings of the tower crane is recorded, the reduction device of the limiter drives the cam, and the convex block on the cam presses down the microswitch, thus blocking the corresponding slewing control circuit and ending the slewing activity.
