Abstract: A wheelchair is provided with a helical drive mechanism. A rectilinear input to the helical drive causes an output gear to rotate, thus providing power to rotate the driving wheels of a wheelchair. The helical drive may include, for example, a compound helix, a drive with a twisted flat bar, or a concentric helix drive. Add-on components may be provided to convert a conventional wheelchair to a wheelchair powered by a helical drive mechanism.

Abstract: A bicycle with a drive mechanism using reciprocal rectilinear pedal motion to propel a pinion gear against a crown gear face associated with a rear bicycle wheel, rotating the rear wheel. The pinion gear receives motion from a helical member surrounded by a slider. Each pedal is united with the slider which moves linearly along a guide or track, forcing rotation of the helical member as the slider is pushed rearwardly by a pedal. A freewheel or overrunning clutch permits power transfer only when the pedal moves rearwardly and allows freewheeling when the pedal is reset. Reciprocal, linear pedal strokes power the bicycle.