Fecha de publicación: 22/08/2000 Fuente: Wipo "precision farming" The invention provides an eccentric wherein the amplitude of reciprocation, or throw, is continuously variable, during operation, from zero to a maximum. This represents an improvement over adjustable eccentric devices in the prior art insofar as the conventional devices needed to be shut down and physically reconfigured to adjust the throw of the reciprocating arm. The invention will be of use in many functions, including precision farming applications.