214 FARM MACHINERY 



and of sufficient number to permit the blast to pass 

 upward through it. The sieve must be well enough sup- 

 ported so it will not sag when loaded, or the grain will 

 settle to the low spot and clog the sieve. The frame 

 should be strong, and perhaps reenforced with a malle- 

 able casting at each of the corners. 



295. The fan consists of a series of blades or wings 

 mounted on a shaft. A blast is thus created to blow the 

 chaff from the grain. An overblast fan delivers the blast 

 backward from the blades at the upper portion of the 

 fan drum. The underblast fan rotates in the opposite 

 direction and delivers the blast from the lower blades. 

 Since there is a tendency to create a stronger blast from 

 the center of the fan than from any other part, bands are 

 placed in the fan by some manufacturers to distribute 

 the blast more evenly across the width of the shoe. 



ATTACHMENTS 



296. The self-feeder and band cutter. The work of 

 the self-feeder is to cut the bands of the bound grain, 

 distribute it across the mouth of the separator, and de- 

 liver it to the cylinder. To carry the bundles to the 

 band cutters, the feeder must be provided with a carrier. 

 A variety of carriers is found in use ranging from a solid 

 canvas or rubber belt to two belts or link belts carrying 

 slats. Both seem to be very satisfactory. 



The band cutters may be knives attached to a rotating 

 shaft, or knives similar to those in use upon mowers, the 

 latter style of knife giving a chopping-like motion into 

 the bundle, tending to draw them into the machine. It 

 is claimed that this type is much better in remaining 

 sharp for a longer time. It is not, however, of as simple 

 construction. 



