Abstract: The invention provides a transport converter dolly for use as the front wheels of a trailer towed by another vehicle, when it is required to provide a substantial spacing between the vehicle and the trailer so as to meet axle loading requirements of the regulatory authorities. The dolly is connected by a towing connection to a transversely-extending bar connected to the rear of the towing vehicle. The wheels of the dolly are forcibly steered as the vehicle train negociates a curve by means of a steering connection between the bar and the dolly wheels. The steering connection preferably is a parallelogram linkage that can be altered in length without affecting the steering it produces. The dolly wheels may be mounted on steerable stub axles or the entire axle may be swivelled by mounting it to the dolly frame via a turntable bearing. The dolly frame may be fixed to the rear trailer or connected thereto by a fifth wheel connection.

Abstract: The invention provides a self-steering dolly that is rigidly releasably connected to the rear of a forward vehicle, such as a tractor-trailer combination, and supports the front end of a towed rearward vehicle, such as a second or "pup" trailer so that the vehicles are in tandem. The wheels of the dolly are mounted on respective king pins; are connected by a linkage and are urged to the neutral or straight-ahead position by a centering device. The means for releasably connecting the dolly and the forward vehicle comprise two transversely extending headed pins on the dolly of the kind employed with a fifth wheel connection engageable in respective releasable spring latches on the frame of the forward vehicle.