"If... you had to shift into low gear, the motor scooter would jump about ten yards ahead..."
Thomas Fogarty
The centrifugal clutch owes its existence to the frustration Thomas Fogarty(b. 1934) experienced With the gears of his motor scooter.
A traditional car clutch works via longitudinal mechanical motion, disconnecting the driveshaft for the wheels from the motor by moving a pressure plate away from the clutch disc.
The centrifugal clutch works differently, using the rotational motion of the motor to engage and disengage the driveshaft The clutch is cylindrical, with the crankshaft from the engine rotating in its center. Attached to this shaft is a pair of weights that are held in place by springs. The crankshaft and weights rotate together, at the same number of revolutions per minute (rpm) as the engine. When the engine increases in rpm, the revolution speed of the weights also increases and they swing outwards. When a certain rpm is reached, the weights swing out far enough to come into contact with the clutch's outer casing, causing this to begin spinning also. This outer casing or hub is attached to whatever the motor is designed to power, causing it to begin to move also.
The weights inside the clutch slip against the hub, allowing it to rotate at a slower rate than that of the engine. As the rpm increases, the weights swing out even further and stop slipping. Eventually this drives the hub at the same rate as the engine, and the maximum speed for the eguipment is achieved. Centrifugal clutches are used in lawnmowers,
chainsaws, motor scooters, mopeds, and racing go- karts, as they are effectively automatic, avoid stalling, and last-a very long time.
