Abstract: A motor driven carriage includes nozzles for directing a cleaning solution to the inside of a trailer on an inward trip and means for stopping movement of the carriage as it approaches the front wall of the trailer. The return cleaning trip is delayed until the rinse water has cleared the cleaning solution from the supply hose. Several alternative dock arrangements are described whereby the carriage-mounted cleaning system may be used for cleaning trailers backed up to opposite sides of the dock, for trailers driven along-side the dock, or for cleaning a plurality of trailers each backed up to the same side of an elongate dock. The heating water and rinse water supply, storage and heating systems of the invention are described, as are the systems for permitting recirculation of water with the various dock arrangements.

Abstract: A carriage is driven from the back to the front of the inside of a trailer, either by rotating nozzles which discharge wash water against the inside of the trailer or by an electric motor. The carriage is guided by two laterally spaced rollers on each side. A hose supplying the wash water and later the rinse water, to the nozzles on the carriage, unwinds from a reel while the carriage is driven into the trailer, but the reel is turned by a motor to pull the carriage rearwardly of and out of the trailer. The trailer rests on an inclined ramp, with the rear edges abutting resilient pads for sealing purposes, the pads being placed around an opening in a partition in the building in which the carriage is housed. A wash tank receives liquid draining from the inside of the trailer, both wash water and rinse water, while a boiler heats the wash water.