I assume you are talking about a Cub Cadet model 73. IH built Cub Cadets are garden tractors, but they also built Cadet's, which are lawn tractors/riding mowers. There was not a Cadet model 73.
A model 73 Cub Cadet, and other models, had a "Quick Attach" latching system to lock the mule drive/subframe for the mower deck into the front of the tractor frame. I am not aware of any kind of "Quich Hitch"
Equipment for Cub Cadets, both IH and after market was listed in "Special Duty Equipment" brochures, and they can be found on ebay or from vendors at tractor show that sell brochures and literature.