Lionaxe was the brand used by Jean Lionard, a bicycle component manufacturer based, like so many others at the time, in Saint-Etienne. 'Lion' comes from his surname 'Axe' comes from the companies signature product being replacement hub axles.

The first Lionaxe derailleur model appears to have been called the Westminster. It used a rod operated cog system to move the pulley cage. This design was patented in 1934 and was registered in 1935. The registered design includes a photo showing the packaging describing the product as “Le Dérailleur Anglais” with the model name handily misspelled as “Wesminster”.

The second model, also called Westminster, appears to have been produced in greater numbers. This was a sliding rod touring model with two pulley wheels and the cable running over a roller within a distinctive domed housing. Frank Berto refers to this model as the Westminster Route of 1937. This design was patented in 1935 but its design was not registered until 1938.

The third model was a racing model (Westminster Course?) with a single pulley wheel, but again with the cable running over a roller in its domed housing. This design was also registered in 1938.

I have a derailleur of a fourth design involving a sliding rod and the cable running over a roller (but not in a domed housing). Two different people have told me that this is also a version of the Westminster Route. Discouragingly, Jean Lionard omitted to brand the derailleurs themselves - so it is hard to know the truth of this.