Like the earlier French patent # 889,531 addition # 56,348 the subject of this patent is a derailleur with the geometry and operational attributes of the Huret Dural Competition. However the body of the derailleur is not made of caste aluminium (like the Huret Dural Competition) but constructed with tempered steel rods (like Huret's 'piano wire' derailleurs - the Huret Course Compétition and Huret Route Touriste).
The unique invention described by this patent seems to be the small curving flange on the inner pulley cage plate - put there to prevent the deraileur catching in the spokes. It's an idea adopted by Shimano in the early 1980s that has since been taken up by most contemporary derailleur manufacturers.
Browse associated derailleurs.