An agricultural vehicle (10) includes a coupling structure for making a tool-less attachment between a first connector piece (60, 60A) and a second connector piece (908, 950). The first connector piece has at least one pin (916), and the second connector piece has at least one slot (924) adapted to receive the pin in a receiving pocket (924C) that is circumferentially spaced from an axially-open inlet portion (924A) of the slot. The slot includes an inlet ramp (930) between the slot inlet portion and the receiving pocket, and the inlet ramp is less steeply angled than a second ramp surface (932) that forms a portion of the receiving pocket adjacent the first ramp.
