Wire Straigliteiiing and Molding for 

 Wire Spring Relays 



By A. J. BRUNNER, H. E. COSSON and R. W. STRICKLAND 



(Manuscript received Januai-y 19, 1954) 



The basic design of the wire spring relay departs from c&nventional relay 

 design in many ways. Translation of some of these design departures into 

 commercial relay manufacture has necessitated the development of new 

 machines and new methods because those available were incapable of pro- 

 ducing to the new design requirements. Two developments in this category 

 involved the straightening of large quantities of small diameter wire and the 

 molding of a multiplicity of straightened wire inserts into phenolic resin 

 blocks. The manner in which these developments were reduced from prob- 

 lems to practice is the subject of this paper. 



Part I — Automatic Wire Straightening 



Ordinarily wire is received from suppliers on spools or reels. In the 

 spooling operation a spiral bend is placed in the wire which persists 

 when it is iinspooled. For use as a wire spring in the wire spring relay 

 this spooling bend must be removed if the wire is to be positioned with 

 tlie precision required for the desired functioning of the relay. It is 

 necessary', also, to have the wire free of bends if automatic manufactur- 

 ing methods are to be employed. For these reasons, it is important that 

 the nickel silver and silicon copper wire used in the Avire spring relay be 

 straightened as the initial operation in the manufactiu'e of wire block 

 assemblies or "combs" for these relays. 



Wire straightening can be accomplished by cold working the wire 

 under controlled conditions until sufficient stress has been l)uilt up, 

 particularly at the surface, to make the wire resist bending efforts. 

 The degree of straightness reciuired is governed, of course, by the de- 

 sired performance of the comb in the operation of the wire spring relay. 

 For the 0.022()-inch nickel-silver wire used in the twin wire comb this 

 has been established, for example, as a deviation not exceeding 0.010- 

 inch from absolute straightness measured at the contact end of the comb, 



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