THE BELL SYSTEM 



TECHNICAL JOURNAL 



VOLUME XXXII MAY 1953 nuubbr 3 



Copyright, 1952, American Telephone and Telegraph Company 



Solderless Wrapped Connections 



Introduction 

 By J. W. McRAE 



(Manuscript received February 9, 1953) 



In the telephone plant during the course of a single year, the operation 

 of connecting a wire to a metal terminal is carried out approximately 

 one billion times. Many of these connections are made in the factory. 

 Others are made during the installation of equipment and a substantial 

 number are made in the course of normal operation of the telephone 

 plant. Successful functioning of the plant depends on trouble-free per- 

 formance of each of these connections, most of which are now soldered 

 in accordance with long-standing practice. Recently, a new technique 

 for joining wires to terminals has been developed which will have im- 

 portant technical and economic advantages in the Bell System and 

 which should have similar advantages in other fields. 



The immediate need for a new connection arose with the develop- 

 ment of the new wire spring general purpose relay.* In this relay the 

 terminals appear in the form of closely spaced wires and the standard 

 methods of applying connections were not satisfactory. Since the pro- 

 duction schedule for these new relays required something like fifty 

 million connections a year on relay terminals alone, an intensive effort 

 was made to devise a satisfactory method for wiring. The first result 

 was the development of a tool which could wrap a few turns of wire 

 around the terminals of the relay, and do this efficiently on the closely- 



* Keller, A. C, A New General Purpose Relay for Telephone Switching Sj^stems. 

 Bell System Tech. J., 31, pp. 1023-1067, Nov., 1952. 



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