Converter dolly

A converter dolly for connecting a second trailer in tandem to a first trailer is provided. The converter dolly comprises a base, a connector frame pivotally connected to the base for horizontal movement about a substantially vertical axis, a dolly locking structure, and a plurality of ground engaging wheels carried by the base. The connector frame includes a hitch for pivotally connecting the connector frame to the forward wheeled vehicle for substantially horizontal movement about a substantially vertical axis, and a fifth wheel assembly fixed on the connector frame to pivotally connect the connector frame to the rear wheeled vehicle for substantially horizontal movement about a substantially vertical axis. The fifth wheel assembly includes a fifth wheel locking having an unengaged position and an engaged position for preventing rotational movement between the connector frame and the rear wheeled vehicle in its engaged position. The dolly locking structure is in its unengaged position when the fifth wheel locking means is in its engaged position to thereby facilitate maneuverability during reverse motion of the tandem trailer assembly.