Elevator safety device can eliminate or reduce the risk of running lifts, safety devices can be a single device, there can be multiple actions interlock safety device. Is to control the way down the elevator speed governor safety device. Common are thrown ball thrown block and two, the device using centrifugal principle to dump block (ball) rotation of the centrifugal force, reflecting the speed of the elevator. When the elevator down to normal speed, the block (the ball) to the centrifugal force is not outside the set range, the device does not move; When the elevator speed decreases, the centrifugal force to block (the ball) a substantial rotation speed to governor action , cut off the control loop, the traction machine stops and the brake, forcing the elevator stopped, and, if necessary, to safety gear. Governor general on the floor installed in the elevator machine room or shaft top. Elevator Buffer is located in a flexible schedule to stop the end of the device, installed in the car and the bottom of the weight limit of travel position, car buffer and sub-categories of re-buffer. Buffers are storage type (spring) and energy type (hydraulic), with rated speed 1m / s below the elevator with storage type, energy type can be used for any speed of the elevator. The role of the buffer when the speeding car or counterweight, in the governor action, safety gear not brake, while the fast approaching car or heavy rail end, the car or counterweight will absorb all the kinetic energy.