Abstract: A grinding mill grinds grains or similar foodstuffs, while the concept of the invention could also be applied to other feed materials. The grain is fed at a controlled rate to an impeller chamber, ground by the impeller until a small enough size to fit through a sieve, and separated into a sample cyclone stream and a bulk or waste cyclone stream. Each cyclone includes a central air return duct which channels air back to the grain feeder chamber and then into the impeller chamber. By having the air from grinding recirculated back to the grinder after separation, the grain grinding process is cleaner and results in less moisture loss.

Abstract: To enable a tractor bonnet to be opened and closed it is pivotably connected near its front end to longer arms of respective laterally-spaced interconnected bell-crank levers which are pivotably mounted about a common transverse axis on an upstanding sub-frame secured to the tractor's main frame. When the bonnet has been initially moved forwardly, thus pivoting the levers relative to both the bonnet and the sub-frame, the shorter arms of the levers abut against the sub-frame whereafter the rear end of the bonnet is secondarily moved upwardly and forwardly into opened position by pivoting the bonnet relative to the stationary levers. The bonnet is closed by performing the same movements in reverse sequence, a transverse arch preferably being so fixed relative to the main frame as to guide the bonnet near the end of its initial closing movement.