This patent describes the Hercules Herailleur, a tidy but unexceptional derailleur. It‘s most unusual features are probably its cheesy name, its very (ludicrously?) short pulley cage and the fact that it is shown with Hercules’ rather elegant, handlebar fitting, Syncro Switch three speed hub control lever. When it was released commercially, the Herailleur was controlled by a conventional, friction, down tube lever.
Thomas Alfred Yapp received an OBE in January 1945, at which time he was described as the ‘works manager of The Hercules Cycles & Motor Company Ltd’.