Spring Unit Manufacturer, Suppliers and Exporter in India

This could also be used to wind a weight on a cord showing the change from potential energy to kinetic, and back, in the raised weight. 

The steel shaft carries a clock spring with a free wheel device, winding ratchet and aa 56mm diameter aluminium 'V' pulley. 

Supplied complete with driving belt.

Conversion of potential energy in a wound-up spring to electrical energy.