US Patent 7104563 Integral locking coupler

An integral locking coupler comprising a locking mechanism mechanically coupled to a set of engagement pins for securing a coupler to a receiver. The locking mechanism translates movement to the engagement pins to move them to and from an extended position and a retracted position. When in the extended position, the engagement pins engage the receiver thereby securing the coupler. When in the retracted position, the engagement pins are generally contained within the coupler housing allowing the coupler to be inserted into and removed from the receiver.