ISO 10243
ISO 10243 - Tools for pressing, compression springs with rectangular section, housing dimensions and colour coding
Compression springs wound from rectangular wire, used in press tools, moulds and clamping devices where a high load is needed in a small space. A size is a housing: the hole diameter DH the spring sits in, the rod diameter Dd it runs on and the free length L0, with hole and rod toleranced H15 and h15. Each housing is offered in four spring rate classes, identified by paint: light (green), medium (blue), strong (red) and extra strong (yellow). The class fixes the largest working deflection - 40 % of the free length for light, 37,5 % for medium, 30 % for strong and 25 % for extra strong - so the same housing gives a very different force depending on the class. Hole diameters run from 10 to 63 mm for the light and medium classes and to 50 mm for the strong and extra strong ones, free lengths from 25 to 305 mm. The document fixes the housing, the spring rate and the colour only, not the wire cross-section, the material or the service life.