The cockchafer was also a Victorian-era device in prisons used as a form of punishment. It was basically a specially-built treadmill, from which the unfortunate bastard on it could not escape.
As I understand the device, think of a paddle-wheel on a steamboat. Now imagine trying to walk up that endlessly turning wheel. That's the cockchafer.
I first read about the device in Crichton's "The Great Train Robbery".