Comparison and Research of Two Kinds of Counterweight Safety Gears

Some times counterweight safety gear is installed.There are two kinds of safety gears,one kind is to protect the passengers under lift car or counterweight,another one is to prevent over speed of the rising car.In this paper,the purpose,development,operating principle,structure of these two kind counterweight safety gears are introduced,and requirement of relative over speed governors are compaired and analyzed for reference.