Super-Leader Route (4th style) derailleur

I am a bit of a fan of the Super-Leader Route. It is a very simple design, executed to a very high standard. Two features, in particular, stand out:

The pulley cage design was very modern - and could easily have come from a 1990s derailleur. The slightly offset guide pulley with sensible chain pusher plates, the detailing around the tension pulley, the generally simple design - all these were rarities in the 1940s.
The use of a single spring to both operate the sliding mechanism and to provide chain tension was also innovative. This is not a feature that has survived on modern derailleurs, but it was extremely common in the 1950s on top selling Simplex, Huret and Cyclo models. I can't immediately think of an earlier example of it then the Super-Leader Route.

The Super-Leader Route was sold with a choice of a clamp on bracket, or one of several brackets that attached to the 'standard' chainstay braze-on of the time. Over its product life it was fitted with one of three diferent types of pulley wheel:

Conventional unperforated steel pulley wheels with ball-bearing races that used adjustable cones that threaded together.
Unusual unperforated steel pulley wheels with ball bearing races. The pulley wheel was split into two halves that were held together with pins held in place by circlips on one side of the wheel.
Even more unusual perforated steel pulley wheels with ball bearing races. Again, the pulley wheel was split into two halves that were held together with pins, but this time the pins were held in place by circlips on both sides of the wheel.

Pulley wheels were clearly some kind of issue for Super-Leader, but you could get the worrying impression of a solution looking for a problem.

I think this is a late example with a clamp-on chainstay bracket. I think it is late because it has perforated two-part pulley wheels, held together by Super-Leader's distinctive pins with clips on both sides.

Derailleur brands: Super-Leader
Country: France
Date of introduction: 1946
Date of this example: unknown
Model no.: unknown
Weight: 288g including chainstay bracket
Maximum cog: unknown, but the relevant patent shows a 26 toothed bottom sprocket
Total capacity: unknown
Pulley centre to centre: 75mm
Index compatibility: friction
Chain width: 1/8”?
Logic: low normal
B pivot: none
P pivot: sprung
Materials: steel