Patent ID: 8794657

Claim:
An apparatus for engaging a generally vertical member of a vehicle, the apparatus comprising: a first plate secured in a generally fixed orientation with respect to the vehicle, wherein the first plate comprises a throat for accommodating the generally vertical member of the vehicle, a notch angularly displaced from the throat, and a contact surface angularly displaced from the notch, and wherein the notch and the contact surface are located on a perimeter of the first plate; a second plate rotatably moveable with respect to the first plate between a first position and a second position, wherein the second plate comprises a first arm and a second arm, wherein the second arm is in substantial alignment with the contact surface when the second plate is in the first position, and wherein the first arm extends across the throat and the second arm is in substantial alignment with the notch when the second plate is in the second position; and a biased latch having a longitudinal axis and secured to the second arm, wherein the biased latch is moveable between an engaged position and a disengaged position, wherein the biased latch is urged in a direction parallel to the longitudinal axis toward the engaged position, wherein the contact surface retains the biased latch in the disengaged position when the second arm is in substantial alignment with the contact surface, and wherein the biased latch engages the notch when the second arm is in substantial alignment with the notch, thereby securing the second plate in a generally fixed orientation relative to the first plate for enclosing the generally vertical member within the throat.