FARM MACHINERY 295 



Several devices have been invented to spread the manure 

 over a wider swath than the width of the machine. Under 

 average conditions the machine requires all the power avail- 

 able to properly pulverize the manure needed to cover the 

 width of the machine. 



Retarding Rake. To prevent the manure from being 

 thrown over in large bunches, a retarding rake is provided in 

 front of the beater. In some machines this is given a vibra- 

 ting motion which tends to level the load. 



Apron Drives. There are at least two mechanisms in use 

 for moving the apron at various rates of speed toward the 

 beater. One is the worm drive, in connection with a face 

 wheel and pinion to give variable speeds. This device gives 

 a uniform motion and is positive, 

 preventing the apron from mov- 

 ing too fast, as when the spreader 

 is ascending a hill and the load 

 has a tendency to slide back into 

 the beater. As a general rule, a 

 worm gear when used in this 

 way does not wear well. Some 



-*,-'. . . Fig. 185. One type of driving 



Of the latest machines have thlS mechanism to the apron. 



gear inclosed so as to run in oil. 



The ratchet drive is simple but does not give a steady 

 motion. It is very easy to obtain a wide range of speed with 

 this device. The ratchet acts only in one direction, and in 

 hilly localities the apron must be provided with a brake to 

 prevent it from feeding too fast in ascending a hill. 



The return motion for return-apron spreaders is usually 

 separate from the feed, and safety devices are provided to 

 prevent the possibility of having both motions in gear at the 

 same time. 



