568 



THE BELL SYSTEM TECHNICAL JOURNAL, MAY 1953 



wind is opposed by the locking in effect of the diss3Tnmetry which in 

 the most preferred types of terminals, as in Fig. 8, comprises abrupt 

 changes in direction around the periphery of the terminal cross section. 

 Some experiments were made with a cyhnder whose cross section, as 

 shown by Fig. 12, consisted of parallel sides with a semi-circle on each 

 end. When the length A was twice the width, the top curve of Fig. 12 

 shows the stripping force as a function of the winding force. Assuming 

 that most of the grip occurs on the two semi-circular surfaces, the hoop 



12.2 



YIELD STRESS IN PER CENT 

 24.4 36.6 48.8 



18 

 17 

 16 

 15 

 14 

 13 



12 

 Q 



i" 



O 

 Q. 



lU 



^ 9 



O 



u. 



Q. 

 |7 



6 



5 

 4 

 3 

 2 

 1 

 



3 4 



LOAD IN POUNDS 



Fig. 12 — Stripping force as a function of winding load for an elliptical type 

 terminal. 



