SOLDERLESS WRAPPED CONNECTIONS 



PART I 



535 



terminal size is changed to 0.020'' x 0.062'' there is considerably less 

 energy stored in the terminal and slightly more in the wire. Inasmuch 

 as a screw connection in most cases depends on the human element, 

 that is the amount of torque applied by the operator, it can be expected 

 that some screw connections will be made with a force that may vary 

 from 75 lbs to 150 lbs. The wrapped connection on the other hand, 

 being made wil h a calibrated tool, can be expected to give substantially 

 the same contact force at all times. 



In order to understand more clearly how the wire and the terminal 

 interact when they are under mutual stress and exposed to heat, the 

 elastic deformation of the wire and the terminal must be analyzed. It 

 has been sho^Mi in Fig. 4 that the wrapped wire on the four sides of the 

 rectangle is under tension. This tension causes the terminal to twist. 

 If instead of a helix the terminal were surrounded by a series of hoops, 



NO CONTACT FORCE -^ 



CONCENTRATED _^ 

 CONTACT FORCE 



STIFF 

 TERMINAL 



INDENTATIONS 



AND 

 CONCENTRATED 

 CONTACT FORCE 



COMPRESSION 



RELATIVELY 

 SOFT WIRE 



TURNS 



LONGITUDINAL TENSION IN A WIRE 

 CAUSES TERMINAL TO TWIST 



(b) 



MODEL MADE WITH A RUBBER 

 TERMINAL WRAPPED WITH 

 RUBBER TUBING EMPHASIZES 

 THE TWIST PRODUCED BY 

 THE LONGITUDINAL TENSION 

 IN THE TUBING 



Fig. 10 — (a) Longitudinal tension in wire causes terminal to twist, (b) Model 

 made with a rubber terminal wrapped with rubber tubing emphasizes the twist 

 produced by the longitudinal tension in the tubing. 



