Wire forming apparatus for torsion springs

Claim 1

A wire forming apparatus for producing torsion springs, comprising: a first servomotor for rotating an arbor having a diameter corresponding to a central diameter of said torsion spring to be produced; feed rollers for feeding a wire onto said arbor; a second servomotor for reciprocally moving said arbor in an axial direction in accordance with a desired pitch for said torsion spring, said second servomotor rotating said feed rollers to feed said wire onto said arbor; a terminal forming mechanism provided around said arbor for forming terminals of said torsion spring; a cutting mechanism provided between said arbor and said feed rollers for cutting said wire; a microcomputer adapted to generate control signals for controlling said first and second servomotors, said terminal forming mechanism and said cutting mechanism; an input unit connected to said microcomputer for supplying torsion spring data required for generating said control signals; a detecting mechanism connected to said microcomputer for supplying second signals detected during the production of said torsion spring to said microcomputer so that said microcomputer can generate additional control signals thus achieving feedback control; and said detecting mechanism comprising a first detecting unit placed at a predetermined position apart from said arbor for detecting a fitness of a feeding length of said wire, a second detecting unit provided around said arbor for detecting a fitness of the shape of said terminal after said terminal forming, a third detecting unit provided near said arbor for detecting a limit position of said reciprocal movement of said arbor in said axial direction, a fourth detecting unit provided around a spindle of said arbor for detecting the returning of said arbor to its original position prior to producing said torsion spring, a fifth detecting unit provided around said arbor for detecting a variance of a winding angle of said torsion spring, and a sixth detecting unit provided between said feed rollers and a wire supply source for detecting a final end of said wire.