This device is mainly applied to a variety of shutte doors, shutter windows,
etc. It is installed on the reel (beam tube). The door curtain may drop quickly
andcause danger when the chain breaks, or when the electric brake fails. or
when the overloaded transmission gear is damaged. The device is able
toprevent the door curtain from dropping suddenly and protect people
and property by automatically brakingthe reel and cutting off the power
of the motors imultaneously.