How will your beast open its mouth?
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More about cranks
A crank is a stiff arm fixed to a shaft so that when the shaft rotates the arm rotates too. Cranks are often attached to handles and used to make tightening and turning easier. You will have used a crank if you have ever had to remove the wheels nuts when changing a car tyre.
In simple mechanisms the crank can be used to turn rotating motion (the turning of a handle, for example) into reciprocating or oscillating motion. Reciprocating motion is movement backward and forward in a straight line. To achieve this, the crank is connected by a link to a slider. You can see this by using the link in More?
Oscillating motion is movement backwards and forwards like a swing; the movement path is part of a circle; not a straight line. To achieve this the crank is connected by a link to a lever. The distance moved by the slider or the lever will be determined by the length of the stiff arm. This is usually called the 'throw' of the crank.