DEVELOPMENT OF A VIBRATORY POTATO DIGGER FOR SMALL FARMS

The performance of the vibrating blade, attached to a two-wheeled and hand-steered 7.35 kw tractor, was improved by increasing frequency while reducing amplitude. Increased frequency assisted the travel speed of the machine by better feeding of materials into the digger blade and by enhancing soil separation. Vibrations with higher amplitude and frequency allowed the machine to travel faster for a given engine and transmission speed of tractor. Slippage of the wheels with lower amplitude and frequency was the major factor limiting the travel speed. The effects of vibrations on the unrecovered and damaged potatoes were not clear. The sum of unrecovered and damaged potatoes ranged from 1.25 to 8.35 percent. It was found that the total acceleration of the vibrating blade was approximately proportional to the amplitude and to the square of frequency. A parameter-rho (a ratio of acceleration of the vibrating blade to the travel speed of tractor) was introduced and found to evaluate the performance of the blade better than an existing parameter-lambda.