1130 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1956 



•- *•«!»' ■^J^TTT' 



Fig. 2 — The network test machine. 



to assure the proper sequence and timing of the conditioning and testing 

 events occurring at the various positions. Table II shows the order of the 

 positions and the approximate timing, with respect to cam rotation. The 

 result of the test at each test position is remembered by a self-locking 

 relay until the fixture comes just opposite the entrance to the correspond- 

 ing rejection chute. At that instant a cam switch closes and causes re- 

 jection if the test result was a failure. Unloading into the rejection chutes 

 is effected by compressed air operated cylinders as explained below. 



The clamping movement of each fixture as it leaves the loading area 

 (entering position 7) is driven by a helical spring which lowers the con- 

 tact fixture over the terminals of the network, bringing spring loaded 

 plungers into contact with the terminals. (See Fig. 3) At a rejection loca- 

 tion a plunger rises, driven by an air (cylinder under the control of a sole- 

 noid operated valve. The rising of the plunger first forces the fixture to 



