Related considerations for improving the working level of the

The electric chain hoist, also known as the electric chain hoist and chain hoist, has the characteristics of low lifting speed, high positioning accuracy, stable and reliable operation and relatively low rated lifting capacity. At present, some bridge cranes with lower working level are available. And cantilever cranes are widely used.

In general, the design of this type of crane does not take into account the safety redundancy of the electric chain hoist, and it is not particularly important to improve the grade of the metal parts of the crane. take. According to the relevant requirements of GB/T3811-2008 "Crane Design Code", the design and calculation of the metal structural parts of this type of crane, the safety factor is the largest according to the load combination class A: take 1.48. Take the Q235B material as a metal structure, if the material itself is not considered. Obviously, when the calculated stress of the metal structural part design reaches 98 MPa or more, if the test load of 1.6 times the rated lifting weight is used to check whether the overload protection function of the chain hoist crane is effective, it will pose a greater threat to the strength of the crane metal structure. It may cause various forms of adverse effects such as plastic deformation of the metal mechanism and flange edging of the main beam of the I-beam, thereby increasing the inspection risk of the inspection organization. In view of this, it is worthwhile to examine whether the overload protection function of the crane is effective according to the method stipulated in the “Regulations”. It is recommended that the relevant departments revise the qualification conditions for the overload protection function of the electric chain hoist in the “Regulations”.

The lifting weight corresponding to the overload protection shall comply with the requirements of the “Safety Regulations for Hoisting Machinery” and the relevant technical specifications for special equipment, and the qualification conditions shall be revised to “when the actual lifting weight is 100%-110% of the rated lifting capacity. When the weight limiter works, it is appropriate.