DISRAELI GEARS
Marelmo SNC is the company, and, I believe, the derailleur brand of Giorgio Marchigiano, Gianpetro Mogno and Luigi Ezzu of Torino, Italy. During the 1980s they developed a curious derailleur that used a large, effusively coiled, spring. In principle it was the bastard child of a 1950s pull chain, sliding rod derailleur. However, unlike most of its forebears, it was top-normal.
Unfortunately I don't believe that this wildly eccentric item ever made it into mass production.
see also Italian Patent # 1,211,236 - Marelmo 1987
see also Italian Patent # 1,211,236 - Marelmo 1987
see also Italian Patent # 1,219,021 - Marelmo 1988
see also Italian Patent # 1,219,021 - Marelmo 1988
Marelmo - web site 2001
Marelmo - web site 2001