no BELL SYSTEM TECHNICAL JOURNAL 



wire against the flanges. This type of distributor is practically instant- 

 reversing. 



Breaking of wire during drawing is not frequent, the average weight of 

 wire on the takeup reel being well over 1000 lbs. for the No. 1 Machine 

 and 300 lbs. for the No. 2 Machine. 



Replacements and Safety Features 



The design provides for readily replaceable unit assemblies so that the 

 machines are out of production for the minimum of time when any repairs 

 are necessary. 



To reduce the effect of vibration to a minimum, the main frame of the 

 machine was constructed to keep as much weight as possible close to the 

 floor and thus secure a low center of gravity. All parts revolving at high 

 speed are given a dynamic balance. Welded construction was not as 

 readily adaptable as castings, and would have been noisier. 



Safety features have been incorporated into the design for the protection 

 of^the operators. Doors are provided so that the wire is fully enclosed 

 during the drawing process and all revolving parts are amply protected. 

 The clamping of the reel on the arbor is effected through spring pressure, 

 air being used for releasing and ejecting the reel. An interlock is provided 

 between the reel release and ejector as shown by Fig. 16, Air Valve "C" 

 effecting the reel release and air valve "B" controlling the ejector. Only 

 one valve can be operated at a time, and they must be operated in proper 

 sequence. The master control "A" is left in contact wuth the gear seg- 

 ment of Valve "C" until it is fully opened and the reel released. When 

 "A" registers with the segmental opening, it can be withdrawn and moved 

 over into mesh with segmental gear on Valve "B"; the master Control "A" 

 cannot be disengaged from "B" until the ejector plunger is back in correct 

 position. Additional safety was introduced into the reels by making the 

 flanges of an alloy casting, changing the factor of safety from 4-1 to 8-1. 



The use of high speed machinery with large capacities of the takeup unit 

 and introducing the minimum of slip between the wire and capstan has 

 resulted in meeting the performances anticipated from this development. 



