This is a very basic coupler attachment that will take the male taper on your vacuum cleaner and couple it to another one - I used it to attach a standard Henry bent metal top handle tube (which is male on each end) to a shop-vac hose that comes with a plastic male fitting but no handle.

Suggest printing in PETG, ASA  or PLA+ for best resilience (mine is printed in PETG)

Freecad file is also available so you can tweak it to fit your own needs.