Natural frequency vibrating feeder

Claim 1

A VIBRATING FEEDER COMPRISING: A TROUGH, MEANS FOR RESILIENTLY SUPPORTING SAID TROUGH, A SPRING ASSEMBLY CONNECTED AT ONE END THEREOF TO SAID TROUGH AT AN ACUTE ANGLE WITH RESPECT TO THE TROUGH, THEREBY DEFINING AN ANGLE OF ATTACK DIRECTION, AND AN EXCITER DEVICE CARRIED BY THE OTHER END OF SAID SPRING ASSEMBLY, SAID TROUGH, SAID SPRING ASSEMBLY AND SAID EXCITER DEVICE FORMING A VIBRATORY SYSTEM, SAID EXCITER DEVICE INCLUDING A ROTATABLE ECCENTRIC MOUNTED TO ROTATE ABOUT AN AXIS LYING IN A PLANE THAT EXTENDS GENERALLY LONGITUDINALLY OF THE TROUGH, AND MOTOR MEANS FOR ROTATING SAID ECCENTRIC AT A SPEED APPROXIMATING THE RESONANT FREQUENCY OF SAID SYSTEM IN SAID ANGLE OF ATTACH DIRECTION, SAID SPRING ASSEMBLY INCLUDING A HELICAL SPRING HAVING ITS TWO ENDS CONNECTED RESPECTIVELY TO THE TROUGH AND TO THE EXCITER DEVICE AND HAVING ITS CENTRAL AXIS IN SAID ANGLE OF ATTACK DIRECTION; SAID SPRING ASSEMBLY HAVING A SPRING RATE LATERALLY THEREOF THAT IS SUBSTANTIALLY EQUAL TO OR LESS HALF ITS SPRING RATE AXIALLY THEREOF, AND SAID SPRING ASSEMBLY CONSTITUTING THE SOLE SUPPORT FOR SAID EXCITER DEVICE.