CARD TRANSLATOR FOR NATIONWIDE DIALING 



1093 



PHOTO transistor: 



MTG HOLES MTG SCREWS 



LOCATING AND 

 LEVELING DETAILS 



I fiji iMk ftjii &M tMk AM am tJMkta^ \ ' -^^ 



Fig. 38 — Phototransistor mounts. 



partment are not as free acting as the others. The holes in the partitions, 

 it will be noted, are round. Round holes were used merely as a conven- 

 ience in manufacture. They are of sufficient size to clear the Ught 

 beams that pass through the card formed tunnels. 



PHOTO-TRANSISTOR MOUNT 



The photo-transistors, consistent ^\dth the left and right-hand group- 

 ing of the holes in the cards, are mounted in left and right-hand groups 

 of fifty-nine each. The mounts used comprise frames that are precisely 

 machined, necessary because the activating light beams have to be 

 concentrated on a very small piece of germanium and many variables 

 are involved. These frames normally are secured to the translator frame- 

 work by means of three special mounting screw subassemblies that 

 provide means for positioning and leveling to obtain optimum light 

 distribution over the whole field of fifty-nine photo-transistors. However, 

 it was recognized that the focusing lenses of the photo-transistors should 

 be readily accessible for cleaning and that it should be possible readily 

 to view the light beams transmitted by the card formed tunnels as for 

 instance by placing a piece of ground glass or translucent paper near 

 the end of the card cage. In this way preliminary adjustment of the 

 first surface mirrors, three dimensional adjustment of the light source, 

 etc., can be effected quickly. Accordingly, the special subassemblies 

 include screws that may readily be removed without affecting the posi- 

 tion or leveling adjustments. As a convenience, loose hinges also are 

 provided so that after the mounting screws have been removed, the 



