COMPRESSION SPRING PRODUCING METHOD Russian patent published in 2006 - IPC B21F35/00 C21D9/02 

FIELD: manufacture of helical compression springs operating at impingement of their turns in condition of elevated temperatures.

SUBSTANCE: after coiling spring with pitch exceeding pitch of ready spring, the last is subjected to heat treatment and shot-blast hardening. Then spring is compressed by action of axial load consisting of 10 - 300 F₃ where F₃ - spring force at maximum deformation. It is possible to perform secondary compression of spring by action of load increased in proportion to relation of target camber to camber value caused by first load. Spring may be subjected to action of vibration loads. In order to satisfy high demands made to force parameters of spring the last is dressed after twisting and ends of spring are ground and chamfered.

EFFECT: possibility for making springs with accurate and stable in time elastic characteristics.

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