I think these are like the ones in a coin laundry near us back in the late 60s/early 70s. They went into a distribution spin speed with the full charge of water. Once the load was against the sides of the tub, the drain valve opened. Beyond the distribution speed, I think there was either one or two higher spin speeds. We used to wash our throw rugs in these machines.
the Cape had 5 of these and they were called Milnor My-T-Boys on the window, they had reverse tumbling ,never had seen that before. I remember the distribution spin and all the suds coming down over the glass!
We have quite a few laundromats here in the Atlanta area that still have these up and running.
Very cool machines. Fun to watch and very fun to hear shifting speeds.