I think the Shimano Combi 12 was Shimano’s first parallelogram design - making it a truly epoch making event in the august annals of derailleur history.
Frank Berto refers to this design as an ‘inexpensive copy of the Campagnolo Gran Sport’. Certainly it has only one sprung pivot and the pulley cage pivots exactly on the axis through the centre of the pulley wheels. However the construction reminds me more of the 1962 Campagnolo Sportman.
The Combi 12 was marketed as a set, with the Shimano 3.3.3. three speed hub gear and a four cog sprocket that fitted onto the hub gear. I am confused by the stop screw that restricts the rotation of the pulley cage (see the photos of the Shimano Archery-W)
This example has no outer cable stop adjuster (this was part of a chainstay fitting clip supplied with it) and has an interesting cable routing around a small red roller. It also has a fairly short hanger plate and 9 tooth pulley wheels.
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