Installation of overload limiter for electric single-beam crane

Lifting weight limiter is also called overload limiter. In order to ensure that the electric single girder crane is not overloaded, it is generally necessary to install a lifting weight limiter. The lifting mechanism of the electric single beam crane is an electric hoist. Therefore, the installation form of the lifting weight limiter on the electric single beam crane depends on the installation position of the load sensor on the electric hoist. Generally, there are three installation forms of crane limiter on electric single beam crane: fixed pulley type, hook type and wire rope type.

1. There are two specific installation forms for the fixed pulley type. One is to configure a set of pallet brackets, and slightly lift the fixed pulley shaft to make the sensor installed on the bracket bear the load. The other is to dominate the fixed pulley shaft. Press the sensor into one end of the shaft. Use this shaft to replace the original pulley shaft during installation.
2. The product structure of the hook type installation form has three types: direct display type, FM launch type and separate type. The direct display type is used for nickel-cadmium batteries as a power source, and the hook, sensor, and large-screen display are integrated into one. Mounted on the crane hook. The FM transmitter also uses a nickel-chromium battery as the main power source, but there is no display part. Instead, the sensor signal is tuned and sent to the driver’s cab. The signal is restored by the secondary instrument for control and display. These two types of sensors do not need to be connected to the secondary instrument with electrical buttons, but the price is higher. The separate type transmits the sensor signal to the secondary instrument through the cable. After processing, it is controlled and displayed.

The wire rope type uses a special fixture to install the load sensor on the lifting wire rope, and reacts to the load by detecting the tension of the wire rope. This method is easy to install and has high detection accuracy.

TSG Q7016-2008 “Regulations for the Supervision and Inspection of Major Maintenance of Lifting Machinery Installation and Renovation “and TSG Q7015-2008″ Regular Inspection Rules for Lifting Machinery” both stipulate that electric single-beam cranes should be equipped with lifting weight limiters, and require:

1. Lift the rated load, raise and lower at the rated speed, and brake normally for 3 times during the whole process, and the lifting limiter will not operate;
2. Keep the load 100mm～200mm from the ground, and continue to load to 1.05 times without impact. Rated lifting capacity, check whether the overload alarm signal is issued first, and then cut off the upward movement, but the mechanism allows movement in the downward direction.