An agricultural vehicle includes a coupling structure for making a tool-less attachment between a first connector piece and a second connector piece. The first connector piece has at least one pin, and the second connector piece has at least one slot adapted to receive the pin in a receiving pocket that is circumferentially spaced from an axially-open inlet portion of the slot. The slot includes an inlet ramp between the slot inlet portion and the receiving pocket, and the inlet ramp is less steeply angled than a second ramp surface that forms a portion of the receiving pocket adjacent the first ramp.
