French Patent # 760,854 - Simplex

French Patent 760,854 - Simplex main image

This patent covers Simplex’s signature bell-crank system, used in many of their touring derailleurs for a number of decades. The key feature of this system was that it was top-normal, with the rider doing the hard work of pushing the chain ‘uphill’ from the smaller cogs to the larger ones, and the spring doing the easier work of pushing the chain ‘downhill’ from the larger cogs to the smaller ones.

The derailleur shown is described by Frank Berto as being the 1934 three speed Simplex Tour de France, a high capacity touring model distinct from the more racy Simplex Champion de France models.