| 摘要 |
A pair of flyweights are mounted on a rotatable shaft and actuate a sleeve which is coaxially disposed on the shaft through a pair of radially extending control arms which are pivotally attached to the sleeve. The flyweights are biased inwardly by a pair of springs mounted on the control arms. On the opposite end of the sleeve is a bearing which provides a physical connection between the rotating sleeve and a non-rotating plate carrying a pair of movable contacts which cooperate with stationary contacts mounted on a stationary housing. The flyweights move outwardly upon rotation of the shaft against the action of the springs and move the sleeve axially along the shaft. The inward bias force of the springs decreases rapidly as the pivot connection of the control arms approaches the pivot connection of the flyweights causing an over center-type of action which results in an abrupt electrical connection between the stationary and the movable contacts. When the speed of the shaft is reduced, the flyweights move slowly inward until the pivot connection of the arms is spaced from the pivot connection of the flyweights at which time the spring action increases and causes an abrupt disconnection of the stationary and movable contacts.
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