1 Scope
This part of GB/T 20863 establishes a general classification of cranes based on the number of operating cycles to be carried out during the expected life of the crane and a load spectrum factor which represents a nominal state of load.
This part of GB/T 20863 does not imply that the same method of stress calculation or testing will apply to all types of cranes which come within the scope of this standard.
2 Use of classification
Classification has two applications in practice, which although related can be regarded as separate objectives.
2.1 Classification of the crane as a whole
The classification is first applied by the purchaser and the manufacturer of a crane, between whom agreement is necessary on the duty of the crane. The classification thus agreed constitutes the overall classification of the crane as a whole. It is intended for contractual and technical reference purposes and not for design purposes. The method of determining this classification is set out in Clause 3.
2.2 Classification for design
The second purpose of classification is to provide a basis for the designer of the crane to build up his analysis of the design and to verify that it is capable of achieving the desired life under the estimated conditions of service specified for the particular application. As a person skilled in crane technology, the designer takes the estimated load spectrum data, either provided by the purchaser or predetermined by the manufacturer (as is the case in the design of serial equipment), and incorporates it into the assumptions on which his analysis is based, having regard to all other factors which influence the proportioning of components.
3 Group classification of the crane as a whole
The two factors to be taken into consideration for the purposes of determining the group to which a crane belongs are the class of utilization and the state of load.
Foreword i
Introduction iii
1 Scope
2 Use of classification
3 Group classification of the crane as a whole
4 Group classification of a mechanism as a whole
