BS 5237:1985

Foreword
Committees responsible
Specification
1 Scope
2 Types of lifting twistlocks
3 Form and dimensions
4 Material
5 Rating
6 Thread on lifting twistlock shaft
7 Testing
8 Marking
Appendices
A Method of establishing limits on positioning of
   centres of lifting twistlocks used for lifting,
   location and restraint
B Notes on design, selection and use of lifting
   twistlocks
Tables
1 Minimum lateral and longitudinal float requirements
   for a range of twistlock dimensions
2 Centre-to-centre dimensions and tolerances between
   lifting twistlocks: fixed centres
3 Rating of lifting twistlocks
4 Dimensions between centres of apertures in container
   corner fittings (upper face of top fittings or lower
   face of bottom fittings) and relevant tolerances
5 Values of parallelogramming (X) for different
   container sizes
6 Example of application of method of calculation of
   tolerances on centre-to-centre dimensions for
   twistlocks with fixed centres
Figures
1 Dimensions of twistlock
2 Suitable dimensions for corner locating spigots for
   use in conjunction with lifting twistlocks
3 Notations for dimensions between lifting twistlocks:
   fixed centres
4 Manner of loading for proof loading
5 Plan view of corner fitting
6 Plan view of an arrangement of twistlocks
7 Relationship between allowable difference between
   diagonals (K) and parallelogramming (X) of container
8 Relative positions of corner fittings and twistlock
   spigots

Specifies dimensions, materials test requirements and marking for fixed and floating centre twistlock heads, and adjacent portions of the shank, used in lifting frames to lift freight containers or other equipment filled with ISO corner fittings. Appendices explain the basis on which the spacing dimensions and tolerances were calculated, and give guidance on the design, selection and use.

This British Standard specifies the characteristics of the head and adjacent portions of the shank and the dimensional requirements and material properties for lifting twistlocks used in conjunction with series 1 freight containers that comply with BS 3951-1.1 and are equipped with corner fittings as specified in BS 3951-1.2. Test load, rating and marking requirements are also specified.

Certain dimensions of the lifting twistlocks are specified on the assumption of correct spacing of the twistlocks in the lifting frame. It has therefore been necessary to specify the centre distances which apply. For fixed centre twistlocks the tolerances on these distances are also specified (see Table 2). These dimensions and tolerances are based on series 1 freight container and corner fitting dimensions. The method by which the tolerances are derived is given in Appendix A. Appendix B outlines the factors to be considered in deducing the maximum imposed load on the twistlock.

The attachment of lifting twistlocks to their relevant supporting members is not covered nor are details of safety interlocks or position-indicating devices. The end of the shank and the method of attachment to the operating mechanism and spreader are not specified.

NOTE The titles of the publications referred to in this standard are listed on the inside back cover.