255 ANNUAL REPORT 
Spindle jCrushers.—These machines differ from the jaw crushers 
inasmuch as the crushing is continuous, being done by a gyrating vertical 
spindle, whose upper part has the shape of a truncated cone and which 
is set in motion by means of a bevel gear. The cone rotates within a 
conical space representing an inverted cone. As long as the machine is 
empty the spindle rotates, though it could assume a gyratory motion. But 
as soon as rock is fed between the crushing surfaces the spindle follows an 
eccentric just beneath the bevel wheel. This causes the head to approach 
and recede from the concave grinding surface of the shell surrounding 
the cone, the movement at the bottom of the truncated cone being greater 
than at the top. The result is a crushing action by pressure which has a 
greater movement upon the smaller lumps than upon the larger. The 
fulcrum of the machine is located at the bottom of the upper journal 
of the spindle. A lump thrown into the machine is broken, drops, 
catches again, is again broken, and thus continues on its way down. 
‘The fineness of the output can, of course, be regulated by regulating the 
width of the throat. 
Professor Richards gives the following table showing the cost of 
crushing by spindle breakers: 
Size of mouth, in inches......... | 4x30 | 6x42 | 8x54 |11x72 |18x 126 
Tons crushed in 24 hours........ | G2 216 540 | 1,080 | 3,000 
ELOTSCPOWelee enn oe eran 3 9 22 45 125 
Costiot breakers. 3 eens $375 $760 | $1,800 | $3,300 | $7,000 
Cost in cents per ton foroil...... OROZ1 ORO 21s SOS OZ ROROZ a MOROZA 
Cost in cents per ton for interest 
and depreciation:..:.........| 02169 | 0.114 | 0-108.) 02099) *|02076 
Cost in cents per ton for power...| 0.541 | 0.541 | 0.541 | 0.541 | 0.541 
Cost in cents perton forlabor....| 5.556 | 1.852 | 0.741 | 0.370 | 0.133 
Cost in cents per ton for wear....| 0.971 | 0.971 | 0.971 | 0.971 | 0.971 
Cost in cents per ton for repairs..| 0.308 | 0.308 | 0.308 | 0.08 0.308 
Total cost in cents per ton....... 7.566 | 3.807 | 2.678 | 2.310 | 2.050 
Comparative tests of the Gates Iron Works have shown the following 
results in crushing a hard granite with a crushing strength of 30,000 
pounds per square inch, in lumps as large as the machine would take. 
The Blake crusher represents the jaw crusher type, the Gates the 
spindle crusher type. 
