Automatic Contact Welding in Wire 

 Spring Relay Manufacture 



By A. L. QUINLAN 



(Manuscript received January 19, 1954) 



Welding of precious metal contacts to the new wire spring relay has pre- 

 sented some unusual manufacturing problems. As the name implies, the 

 springs of these relays are wires. The contacts through which electrical cir- 

 cuits are established consist of small blocks of palladium accurately and 

 securely welded to one end of these wires. The wires, arranged in a parallel 

 array, are imbedded for part of their length in molded phenol plastic to form 

 parts which will be designated as "combs" in this paper. There are two 

 kinds of combs, those with the wires arranged in pairs called twin wire 

 combs, aiid single wire combs. Different welding techniques are required, 

 each of which will be described separately. 



INTRODUCTION 



The ^^dre spring relay, Fig. 1, was designed wdth such advantages over 

 U and Y t3'pe relays as higher operating speed, longer life, lower power 

 consumption and lower cost, as described in a recent article in this Jour- 

 nal.* The lower cost will be achieved largely by reduction of assembly 

 labor time, by reduction of adjustment effort after assembly due to 

 greater precision in the manufacture of component parts and by exten- 

 sive use of automatic manufacturing processes. To attain these goals 

 the closest cooperation has been necessary, particularly during the design 

 stage, between Bell Telephone Laboratories relay engineers and Western 

 Electric development engineers. Small lots of wire spring relays of several 

 of the early designs were manufactured by the Western to furnish the 

 Laboratories \vith relays for testing. These operations provided Western 

 development engineers with valuable manufacturing experience. 



The present design of relay has been in production on a pilot plant 

 basis. The contact welders have operated as individual units during 



* A. C. Keller, A New General Purpose Relaj' for Telephone Switching Systems, 

 B.S.T.J., Nov., 1952. 



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