"The Doyen company of Brussels was responsible for the importing of Lanz tractors into Belgium and England. Around 1927 they introduced their own tractor design, based ...
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around a Lanz engine and heavily influenced by the French "Polyculteur Dubois" which appeared in 1919. As with the Dubois, the front of the Doyen tractor could be raised or lowered using a screw thread attached to the front axle, which was useful for improving stability of the tractor or altering the depth of a mounted plough. The Lanz engine employed by the Doyen was a single-cylinder horizontal semi-diesel type, which produced around 17 hp at 420 rpm and was water-cooled. Transmission was by chain and there was no differential. Doyen ceased tractor production in 1928, and the export of Lanz tractors to Belgium and her colonies was subsequently taken over by Clayton & Shuttleworth. " (http://www.steel-wheels.net/doyen.html)
