in use, ultra-overturning moment is one of the main accident. Therefore, the torque limiter is necessary for the tower crane integrated torque limiter
system accuracy not worse than ± 5%, in any case, the overload alarm shall not be greater than the measured load moment conditions corresponding to the rated lifting crane torque of 110%; also provides technical requirements: The actual load moment to rated load moment conditions corresponding to 90% when the early warning signals, the appropriate conditions to meet or exceed the rated lifting torque overload signal when issued, and automatically stop the crane to a dangerous direction to run. In lifting torque limiter integrated error should not exceed 10%.Maximum speed in the trolley than 0.67m / s of the crane, when the car is running forward, cranes moment 80% of the rated torque, should be automatically converted to low-speed operation.Vertical impact of the torque limiter installed in the crane, the tower under wind conditions on the bearing surface of the lateral axis vertical to 4 ‰, lifting using cranes installed, in the absence of load cases, the tower and the ground The vertical error of no more than 3 ‰.
We can see from the above two criteria, the verticality of the tower and the ground is provided starting from the requirements of stability, if the vertical too, the focus will move the entire tower crane, and hook the rate will increase accordingly, The result is to reduce torque and increase stability of the overturning moment. If at this time to adjust the torque limiter
, precision index will exceed the required standards. In cases where the wind, the weight of hanging meet a variety of factors such as overloading, the stability of the tower crane will be greater, when more than stable limit torque occurs when the tower overturning accident. The impact of maintenance on the torque limiter torque limiter though arched structure is simple, but if the loss of security disrepair detection accuracy of the torque limiter has some impact. Torque limiter in the bow, the micro switch waterproof performance is poor, often malfunction, replace the crane driver trouble, unauthorized removal of the electrical circuit, torque limiter lost security features. As the micro-switches sun and rain, parts of aging, so that movements are not flexible, not reliable, torque limiter useless. Crane driver does not check the ground, ground maintenance, torque limiter did not find the existence of hidden dangers. Crane did not carry out regular inspection torque limiter check.
Units must be developed using the crane to use a system whereby its periodic calibration cycle. Maintenance workers of the technical requirements of the torque limiter
impervious to eat, and some even believe that amplitude-speed function is dispensable car wrapping; debugging, since the weight error, increase speed, inertia, magnitude error, the greater torque error.