A Cambridge Roll is a segmental roller made up of cast iron rings with a distinctive shape. The design was patented by aWilliam Cambridge of Bristol in the mid 19th century.
The roller is designed to break up small clods and compact the ground so it retains moisture in the seed bed. A flat roll creates to smooth a surface and allows rin to run-off too fast were as the ribs on the roller create a series of groves which slow the flow of rain water over the surface and allow it to soak into the ground were it is retained longer.
Several 'modern' variations on the design have been created over the years.
- Furrow press wide spaced rings or a spiral designed to break larger clods up during ploughing.
- Ring roll - similar segmental designs
- A modern roller using 'old' railway wagon wheels which is much heavier than a std Cambridge roller.