BS 5237:1985

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.