Patent ID: 8181749

Claim:
A speed governor for an elevator, comprising: a governor sheave, around which a governor rope connected to a car is wound, the governor sheave being rotated in a first direction along with ascent of the car and being rotated in a second direction opposite to the first direction along with descent of the car; a first speed detecting mechanism provided to the governor sheave to detect based on rotation of the governor sheave that a running speed of the car has reached a first threshold value; a rotary body to be rotated by transmission of the rotation of the governor sheave; a second speed detecting mechanism provided to the rotary body to detect based on rotation of the rotary body that the running speed of the car has reached a second threshold value smaller than the first threshold value; a clutch mechanism provided between the governor sheave and the rotary body to transmit and interrupt rotation between the governor sheave and the rotary body; a DC generator for generating a current by the rotation of the governor sheave; an actuator for performing switching between transmission and interruption of rotation by the clutch mechanism according to whether or not energization from the DC generator is performed; and a rectifier circuit for allowing the current to flow from the DC generator to the actuator only when a rotating direction of the governor sheave is a predetermined one of the first direction and the second direction.