Automata are usually powered by a crank (the handle). Another sort of crank you'd be familiar with is a bicycle pedal. A crank is an arm at right angles to a shaft (or axle), by which motion is imparted to, or received from, the shaft. It is used to change circular into reciprocating motion, or reciprocating into circular motion.
Crank and slider
A common, simple mechanism used to convert rotational motion into reciprocating linear motion, or motion that goes back and forth along a straight line. Familiar examples are the piston and crankshaft on a locomotive or in a car engine.
Quick return crank
A quick return mechanism such as the one seen below is used where there is a need to convert rotary motion into reciprocating motion. As the disc rotates the black slide moves forwards and backwards. Many machines have this type of mechanism and in the school workshop the best example is the shaping machine. |
