Converter dolly for permitting backing up of tandem trailers

A converter dolly for interconnecting and facilitating backing up of a tandem trailer assembly pulled by a tractor is disclosed. The converter dolly is coupled to the rear of a first trailer for pivotable movement relative thereto about a substantially vertical axis. The converter dolly includes a wheeled frame. A fifth wheel is fixed on the wheeled frame and has a front end defining opposing front corner portions. The wheeled frame includes a coupling assembly for coupling the wheeled frame to a second trailer for pivotable movement about a substantially vertical axis. A locking mechanism cooperates with the fifth wheel and includes a spaced pin housing secured at each front corner portion of the fifth wheel so that when the fifth wheel pivots up or down, the housings move as units with the fifth wheel. A pin is positioned in each housing and movable therein from a retracted to an extended position.