258 ANNUAL REPORT 
> - 
iy) 43 
Zz 
CZ, ¥ 
ma? \ 
aX d 
\ y 
LJ 
PRL 
SSS 
SSS 
SS: 
N; 
SG CK a 1 
a5 O*—K 
ddd LLL Z) x YO MMMM 
a 
Fig. 33. Spindle crusher, Gates type. 
> 
In these tests the Blake crusher was handicapped by its small size 
and the smaller width of throat. The general tendency seems to be in 
favor of the Blake crusher for small and in favor of the Gates for 
greater capacities. The continuous action also is in favor of the Gates 
crusher. 
In cement practice a rock crusher with an average capacity of 25 
tons per hour requires under conditions of maximum load 33 horse- 
power and an average of 20 horsepower. 
Rolls,—These are two iron cylinders revolving on shafts in the 
direction indicated by the arrows in the accompanying diagram acting upon 
the lump of material c on the principle of a toggle joint. The rolls 
are held in position by the journals acting radially upon the lump and 
gradually drawing it down to the narrowest.space. The material is 
broken by true crushing by virtue of the superior crushing strength of 
the cast iron. The rolls consist of a core of soft iron which carries a shell 
