This overspeed governor is used together with bi- directional safety gear.The down dirction braking is as same as that of the conventional down direction safety gear,the working principle of braking, either up or down, is totally same.The tension device of swing type with eccentric wheel brings much better performance of up dirction braking, more reliable and safer.When installing the over speed governor, make sure that the arrow direction on the pulley points to down direction of the lift car. When insalling tension device, make sure that eccentric wheel always touches the end of swing arm and the lower pully can only swing downwards.