Image Number 4 for United States Patent #7581746.
A trailer hitch coupling unit has a hitch pin assembly mounted on a trailer and a hitch receiver assembly mounted on a vehicle. The hitch pin assembly has a mounting plate and a platform forming a ball and socket joint therebetween, rotatably coupling the platform to the mounting plate. A bull nose, having a groove, projects from the bed plate. A first electrical connector is mounted in an axially extending bore in the bull nose. The hitch receiver assembly has a bed plate configured to be mounted on a bed of the vehicle above a rear axle thereof. The bed plate has a first opening configured to receive the bull nose. A locking plate is mounted on the bed plate for axial movement between a hitch pin receiving position adjacent the bed plate, and a hitch locking position spaced from the bed plate. The locking plate has a second opening configured to receive the bull nose. An actuator is operably connected to the locking plate for effecting the axial movement. A locking mechanism has at least two locking arms mounted about the second opening and pivot between a locked position and an unlocked position and are biased to the locked position, enabling ingress of the bull nose and preventing egress once the locking arms engage the groove on the bull nose. A lock release mechanism is operably connected to the locking arms to effect unlocking movement of the locking arms and enabling egress of the bull nose. A second electrical connector is pivotally mounted on the locking plate and positioned to electrically couple with the first electrical connector upon the locking plate moving to the hitch locking position.