The working level is an index to indicate the heaviness of the crane. The purpose of classifying the working level of the crane is to provide scientific and reasonable basis for the design and calculation of the crane, and to provide reasonable and credible basis for the consultation between the user and the manufacturing enterprise. The working characteristic of crane is intermittence of operation and circularity of work. Crane is a work cycle from lifting a goods start, until ー lifting the following items, including crane work and normal rest, a complete process.
The usage level of crane is to divide the total number of working cycles that can be completed by the crane into 7 levels from low to high, using U. , U1 and U2U are shown in table 7-1. Use rating
Total work cycle
How often the crane is used
U0
Cr < 1.60 * 104
Rarely used
U1
3.20 * 1.60 * 104 < Cr "104
U2
6.30 * 3.20 * 104 < Cr "104
U3
1.250 * 6.30 * 104 < Cr "104
U4
2.50 * 1.25 * 104 < Cr "104
Infrequent use
U5
5.0 * 2.50 * 104 < Cr "104
Medium frequent use
U7
1.0 * 5.0 * 104 < Cr "106
More frequent use
