124 



SCIENCE OF SUCCESSFUL THRESHING 



full engagement, the shoes press so hard against the rim 

 of the fly-wheel that they prevent slipping, thus locking 

 the fly-wheel and pinion together. The two shoes are 

 hinged to the ends of the arm. This arm has a long sleeve, 

 which is loose upon the shaft, but at the end of which the 

 pinion is firmly keyed. The sliding ring (Fig. 39), is 

 loose upon the sleeve, and when moved toward the fly- 

 wheel, straightens the toggle levers, thus pressing the shoes 



against the rim of 



ou.HotEs.r- N| i the fly-wheel. The 

 *- sliding r i n g is 



moved by means 

 of the trunnion 

 ring which r e - 

 mains stationary, 

 but allows the slid- 

 ing ring to revolve 

 within it. The 

 trunnion ring is 

 held to the sliding 

 ring by means of 

 the clamp ring. 

 Adjusting the Clutch. The wear on the shoes is 

 taken up by means of the turn-buckles in the toggle levers. 

 They should be so adjusted that the toggle levers will just 

 pass the straight line when the clutch is in engagement, 

 thus relieving the trunnion ring of all side friction ; they 

 should also be so adjusted as to produce equal tension on 



SLIDING RING 

 TRUNION RING 



CLAMP RING 



FIG. 3Q. SECTION OF HUB 

 PORTION OF CLUTCH. 



