Abstract: A coupler for rapidly joining a snowplow unit to a prime mover. A horizontally extended tongue is affixed to the push frame of the plow unit which is insertable into a receiving slot contained in the coupler. The tongue is provided with a pair of contoured camming surfaces that are arranged to translate a prescribed motion to a pair of jaw elements contained in a locking mechanism carried by the coupler. The jaw elements are biased to move in contact with the camming surfaces to first move to a fully opened position to allow the tongue to pass into the coupler and then into closed or locked position wherein the push frame of the plow unit is securely drawn into seated contact against the front wall of the coupler.