RCD,
Bi-directional brakes have been around a long time. I would think that if it was applicable to the elevator industry for some thing other then a roped dumbwaitor we would be working on them too!
In your video the gentleman said it is a Sedgwick rope dumbwaitor. I have a mint condition Matot rope dumbwaitor I pulled out of a building my customer was renovating.
But if you are hungry for knowledge pm me your email address. I have a 10 page write up you are welcome to read...