'Crank pin' definitions:

Definition of 'Crank pin'

From: GCIDE

Crank \Crank\ (kr[a^][ng]k), n. [OE. cranke; akin to E. cringe, cringle, crinkle, and to crank, a., the root meaning, probably, "to turn, twist." See Cringe.]
1. (Mach.) A bent portion of an axle, or shaft, or an arm keyed at right angles to the end of a shaft, by which motion is imparted to or received from it; also used to change circular into reciprocating motion, or reciprocating into circular motion. See Bell crank. [1913 Webster]
2. Any bend, turn, or winding, as of a passage. [1913 Webster]
So many turning cranks these have, so many crooks. --Spenser. [1913 Webster]
3. A twist or turn in speech; a conceit consisting in a change of the form or meaning of a word. [1913 Webster]
Quips, and cranks, and wanton wiles. --Milton. [1913 Webster]
4. A twist or turn of the mind; caprice; whim; crotchet; also, a fit of temper or passion. [Prov. Eng.] [1913 Webster]
Violent of temper; subject to sudden cranks. --Carlyle. [1913 Webster]
5. A person full of crotchets; one given to fantastic or impracticable projects; one whose judgment is perverted in respect to a particular matter. [Colloq.] [1913 Webster]
6. A sick person; an invalid. [Obs.] [1913 Webster]
Thou art a counterfeit crank, a cheater. --Burton. [1913 Webster]
Crank axle (Mach.), a driving axle formed with a crank or cranks, as in some kinds of locomotives.
Crank pin (Mach.), the cylindrical piece which forms the handle, or to which the connecting rod is attached, at the end of a crank, or between the arms of a double crank.
Crank shaft, a shaft bent into a crank, or having a crank fastened to it, by which it drives or is driven.
Crank wheel, a wheel acting as a crank, or having a wrist to which a connecting rod is attached. [1913 Webster]