The famous Colnago Clover was first used in 1970…
“COLNAGO EMBLEM CREATED
After Dancelli’s Milano-Sanremo victory, Ernesto Colnago is inspired to replace his previous eagle emblem with a new mark, the ace of clubs. The logo commemorates the blooming of the spring flowers in Sanremo and Ernesto Colnago’s ambition to be “an ace in cycling”.”
More Colnago history at the official Colnago site.