Online Dictionary

back eccentric Explained

Back eccentric at English => English (Websters 1913) Of Explained:

Eccentric \Ec*cen"tric\, n.
1. A circle not having the same center as another contained
in some measure within the first.

2. One who, or that which, deviates from regularity; an
anomalous or irregular person or thing.

3. (Astron.)
(a) In the Ptolemaic system, the supposed circular orbit
of a planet about the earth, but with the earth not in
its center.
(b) A circle described about the center of an elliptical
orbit, with half the major axis for radius. --Hutton.

4. (Mach.) A disk or wheel so arranged upon a shaft that the
center of the wheel and that of the shaft do not coincide.
It is used for operating valves in steam engines, and for
other purposes. The motion derived is precisely that of a
crank having the same throw.

{Back eccentric}, the eccentric that reverses or backs the
valve gear and the engine.

{Fore eccentric}, the eccentric that imparts a forward motion
to the valve gear and the engine.