attachment adaptor
Kirby 519...You are right about how it was open to pass by the belt. The belt slid into the slot. Once in place, you would turn the front of the adaptor, before clipping on the hose, and it would lift the belt from the drive shaft. Much like a Kirby belt lifter. This was supposed to help lock it(the adaptor) into place, but if you tried to drag the cleaner by the hose, it more often than not would pull the whole apparatus out. Suction wasn't the best, so when we moved to a big house in 1955, our housekeeper had my mother buy the first Constellation model 82.