Centrifugal Clutch
The centrifugal clutch disengages the chain from the engine when the engine is only at idling speed, engaging the drive automatically when the throttle is squeezed and the engine is at full speed. The purpose of this clutch is to avoid having a moving chain when the saw is idling and temporarily not cutting. At idle the chain should not move.
Many rear-handled chainsaws are used in a state, owing to poor maintenance, where there is some clutch drag and so the chain does move slowly at idle. For top-handled saws though, this is extremely dangerous and the clutch (and chain brake) on such a saw must always be functioning correctly.
Some early chainsaws used a manual clutch instead, but this is long obsolete.
Read more about this topic: Chainsaw Safety Features
Famous quotes containing the words centrifugal and/or clutch:
“Travel is like adultery: one is always tempted to be unfaithful to one’s own country. To have imagination is inevitably to be dissatisfied with where you live. There is in men, as Peter Quennell said, “a centrifugal tendency.” In our wanderlust, we are lovers looking for consummation.”
—Anatole Broyard (1910–1990)
“We have no participation in Being, because all human nature is ever midway between being born and dying, giving off only a vague image and shadow of itself, and a weak and uncertain opinion. And if you chance to fix your thoughts on trying to grasp its essence, it would be neither more nor less than if your tried to clutch water.”
—Michel de Montaigne (1533–1592)