The double MNB brake for commercial elevators is two identical brakes mounted on one adaptor flange. When pressure is applied, both brakes operate at the same time. In the event of a problem with one of the brakes, the other is designed to handle the torque load required. Both brakes are equipped with limit switches, which know when the brake is engaged or disengaged.
Ogura Industrial Corp., Box 5790, Somerset, NJ 08875, (732) 271-7371, www.ogura-clutch.com