Looks like an A & E awning that someone added a couple od brackets to prevent the roll from unwinding while traveling. ZipDee used a locking break in it's earlier awnings and later converted to the travel latch. I am not familiar with the A & E setup, but I would have to think they had some way to lock the roller to prevent it from unwinding and becoming a sail at 65 MPH.
Hopefully someone with this type of awning will be able to help more...
Wally Byam Airstream Club 7513