Worthen, William Ezra, 1819-1897, [from old catalog] ed · New York, Appleton · leaf 348
s of a bell-crank, controlled by ascrew. The screw works in a stand, on the top ofwhich is a hand wheel; the hand wheel can bemoved in either direction, and any desirable pres-sure can be brought upon the frictional surfacesby means of the screw. It is not unusual, insteadof two pinions to have one…
Mechanical drawing
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