The children’s pedal car was developed from an early style of transportation that predates the bicycle – the railway locomotive. It operates on the principle of an eccentric axle, its up and down motion turning the wheels. The first pedal cars used this form of propulsion before more expensive chain driven pedal cars became popular.
Locomotives were geared, but pedal cars did not need to carry so much weight so a simpler operation was feasible. This very rare children’s bicycle operates in ta similar way, its foot levers driving a cranked rear axle. It’s a simple design, but though effective to create forward motion, it is not as efficient as the traditional pedal and chain arrangement.
1930s Bicycle with Drive Levers & Eccentric rear axle
16″ Disc wheels with solid tyres
Various 21st century bicycles have been designed with a similar principle. I’m not sure if they have gone into production.
In 1956 a German designer created a bicycle based on the same principle. It subsequently became the Hercules Cavallo. In the video below you can see my friend Ian demonstrating a Cavallo I used to own.