Crank Mechanical System

A crank is an arm attached at a right angle to a rotating shaft by which circular motions is imparted to or received from the shaft. When combined with a connecting rod, it can be used to convert circular motion into reciprocating motion, or vice versa. The arm may be a bent portion of the shaft, or a separate arm or disk attached to it. Attached to the end of the crank by a pivot is a rod, usually called a connecting rod (conrod).

The term often refers to a human-powered crank which is used to manually turn an axle, as in a bicycle crank set or a brace and bit drill. In this case a person's arm or leg serves as the connecting rod, applying reciprocating force to the crank. There is usually a bar perpendicular to the other end of the arm, often with a freely rotatable handle or pedal attached.

Familiar examples of crank systems include:
• Mechanical pencil sharpener
• Fishing reel and other reels for cables, wires, ropes, etc.
• Starting Handle for older cars
• Manually op