This Spanish Utility Model describes a Sanz derailleur that is interesting in a number of ways:
The date of this document is 1954, only a year after Campagnolo had settled on the classic configuration of the Campagnolo Gran Sport. Despite being a very early parallelogram design, it is impressively sophisticated, coherent and composed.
The pulley cage has a large chain-pusher-plate, that might well cause it to change better than a Campagnolo Gran Sport.
Both of the adjustment screws are mounted on the knuckles, which gives a clean and tidy look.
There is a strange anvil-shaped protruberance from the bottom of the p-knuckle - with teeth on the inside to offer a range of positions for the p-pivot spring. This allows you to quickly and easily vary the tension. - something I have never wanted to do - but each to their own.
