Abstract: An improved articulated heavy haul trailer combination comprises a trailing accessory vehicle such as a booster coupled to a main trailer by a coupling. The coupling includes a horizontal hinge, a vertical hinge that allows the trailing accessory vehicle to yaw in a horizontal plane, a spreader extending between the hinges and a hydraulic piston and cylinder. A turn sensor mounted on said combination detects yawing, and a controller reduces the piston and cylinder's downward biasing force on the coupling.

Abstract: An improved removable and installable fender for the bolsters of a trailer group relies on the use of a bracket on the bolster, the bracket having two retaining arms. A single fastening means is provided on the bolster to receive a bolt securing a medial portion of the end of the fender to the bolster, allowing the distal sides of the fender to be retained between the two retaining arms of the bracket and the body of the bolster.

Abstract: An improved removable and installable fender for the bolsters of a trailer group relies on the use of a bracket on the bolster, the bracket having two retaining arms. A single fastening means is provided on the bolster to receive a bolt securing a medial portion of the end of the fender to the bolster, allowing the distal sides of the fender to be retained between the two retaining arms of the bracket and the body of the bolster.

Abstract: A removable gooseneck hitch assembly transitions between an afterward position for hitching to a low bed trailer deck and a forward position by a pivoting arm that moves the forward end of the gooseneck an arcuate path. The invention minimizes the opportunity for debris to interfere with the sliding track assemblies known in the prior art. The assembly provides three degrees of freedom for the gooseneck in low bed mode and restricts the degrees of freedom in vehicle towing mode. A locking member for securing a low bed trailer hitch is also disclosed.

Abstract: A suspension system for towed vehicles automatically adjusts for different payloads and road conditions without the need for manual shims used in prior art suspensions. automatically adjusts a mechanical bias on the vehicle to keep the suspension within a preferred ride height range. A hydraulic cylinder between the frames of the towing and the towed vehicles provides a mechanical biasing force to the towed vehicle. A sensor measures the ride height and causes the hydraulic cylinder to retract or extend according to the bias needed to maintain the suspension in the preferred ride height range.