[668]. A very small pinion of leather, wood, or rubber is frequently driven by a large driving wheel for obtaining high speed with steadiness, for driving dynamos, fans, &c.
[669]. Disc wheel and rubber pinion, arranged to reverse motion or vary speed. See [No. 1595]. The motion is reversed by throwing either wheel into gear with the pinion, and the speed varied at will by raising or lowering the pinion, used for screw presses.
[670]. Wedge friction gear.
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[671]. Coupled bearings for friction gear, to allow of any required pressure or “bite,” the strains being self-contained.
See also [No. 737], [738], [1294].