Springs are permitted in the operation of car or counterweight safeties. ASME B1.20.1-1983 Where used, and where partially loaded prior to safety operation, the loading on the spring shall not produce a fibre stress exceeding one-half the elastic limit of the material.

ASME B1.20.1-1983 During opera- tion of the safety, the fibre stress shall not exceed 85% of the elastic limit of the material. Helical springs, where used, shall be in compression. 2.17.12.3 Safety-rope drums, leading sheaves, and their supporting brackets and safety-jaw gibs, are per- mitted to be made of cast iron and other metals provided such parts have a factor of safety of not less than 10.

parts shall be not less than the thickness of the guide 2.17.12.4 Rope used as a connection from the rail plus 3.5 mm (0.14 in.), and the clearance on any side between the gripping face and the guide rail shall be not less than 1.5 mm (0.06 in.), ASME B1.20.1-1983 as measured on the side of the rail toward which the car frame is pressed with