This is the vacuum I’ve had for some years. Recently I was using it and the head fell off, and not where it has a quick disconnect.
This connection point provides one of the heads axis of rotations. There is a slot where a retention clip rides in a groove while rotating and holding the connection together axially. There is also a seal to maintain the vacuum while it rotates.
After testing it out I had to make the locking tabs a bit longer. Taking measurements was awkward and they were not perfect.
The new part fit in the slot nicely and with a bit of effort the head pushed back on and clipped in place. Back to vacuuming….