This is the second of three derailleur patents filed by the ‘Perm Machinery Factory named for the October Revolution’ in Perm, Russia. These patents have some notable features:
- The first two have one adjustment screw on the centre line of each knuckle, in the style of a Gian Robert.
- All three use aluminium castings for the parallelogram plates (rather than the steel pressings more characterisitic of Kharkov designs of the period).
- They feature a parallelogram spring that is not attached to either knuckle but sits in the centre of the parallelgram, acting between the parallelogram plates.
This particular patent features the distinctive curved parallelogram plates and equally distinctive parallelogram spring design of the Perm derailleur in this collection. However the Perm derailleur in this collection has its adjustment screws placed differently from those in this patent.
- Publisher: Rospatent
- Inventor: Yuri Petrovich Potekhin, Valery P. Kartashev, Leonid I. Arhalovich & Victor P. Moroshkina
- Country: Russia
- Date: USSR application filed September 1979
- Derailleur brands: Perm, ZIF
- Derailleurs: unknown, some similarities to Perm