86 



USRL TEST STATIONS 



Figure 23. Rotator and suspension framework. 



Figure 24. Placing rotator in position in carriage. 



engage the driving motor, and a control for each 

 projects through the housing. Each shaft has a 5CT 

 synchro coupled to it through a 60 : 1 gear train. The 

 synchros are mounted in an auxiliary housing on the 

 side opposite the clutch controls. The driving motor 

 rests on top of the gear box and is coupled to the 

 internal gear train through an assembly that pro- 

 vides for manual operation by a crank. 



The concentric shafts are approximately 3 feet 

 long. The outer one, a 3-inch tube, terminates in a 

 metal framework, adjustable in length. The inner 

 one is extended by a 1-inch pipe of adjustable length, 

 which is terminated in a 4-inch flange, and is centered 

 with the bottom plate of the outer shaft assembly. 

 The approximate load capacity of the rotator is 1,000 

 pounds per shaft. 



Mounting Fixtures. Universal mounting fixtures 

 and others of special application are used for attach- 

 ing test transducers to the various suspension mem- 

 bers. Examples of these fixtures are shown in Figures 

 20A and 20B, which illustrate the devices for 1A and 

 3A hydrophones. Figure 20C shows a fixture used for 

 rigging a variety of small and medium size trans- 

 ducers. 



Carriages. The carriages that are used to support 

 the suspension members roll across the test areas on 

 flanged wheels fitted with brakes and matched to the 

 side rails. An H-type carriage, shown in the fore- 

 ground of Figure 25, is used for supporting trans- 

 ducers that do not require rotation. A turret type is 

 shown in Figures 22 and 26. The upper assembly may 

 be rotated at % rpm by a small synchronous motor 

 acting through reducing gears and a rubber friction 

 wheel. Studs attached to the underside at 30-degree 

 intervals operate a microswitch to indicate at a re- 

 mote point the angular position of the turret. How- 

 ever, because of the superior facilities provided by the 

 rotator, the turret type is now used only for medium 

 and heavyweight instruments not requiring steady 

 rotation. 



A special carriage is used for the rotator assembly 

 with the housing resting on a flat bedplate. A split 

 radial thrust bearing on the underside engages the 

 3-inch outer shaft and adds to the rigidity of the sys- 

 tem. Two lever-operated brakes secure the carriage 

 at any position. 



Screens. Screens are used frequently to minimize 

 standing waves resulting from surface and bottom 



