This is the first of two scans that were sent to me by Vadim Vorontsov. Vadim is the son of Reginald Vorontsov, one of the leading figures at TSKTB (ЦКТБB or ‘Central Design Office for Bicycle Construction’) in Kharkov, Ukraine. These drawings show the derailleur that TSKTB originally developed for the ‘Moscow 80’ bikes that they hoped would be chosen by the Soviet team at the 1980 Moscow Olympic games. After the games had passed they continued to use the derailleur on their ground-breaking Tachyon bikes.
The derailleur was a quality, aluminium item with (I think) Titanium small parts. It used the distinctive Kharkov layout of both adjustment screws being on the front knuckle. This, first, version has a drilled pulley cage.