A large width tool beam (1) for fitting to a tractor hitch is reinforced by a support beam (2) set above the tool beam in a parallel vertical plane. This allows free positioning of the tools along the main beam. The outer ends of the two beams are linked by end braces. The middle sections of the two beams are linked by a hitch frame (5) and by a support brace (3). Connectors at the free ends of the beams enable extension beams to be fitted.