Dispensing apparatus having loss of weight hopper

Claim 1

IN AN APPARATUS FOR CONTROLLING THE FLOW OF MATERIAL, A WEIGH ARM, FLEXURE PLATES SUPPORTING THE WEIGH ARM IN EQUILIBRIUM, A HOPPER ON THE ARM, A POISE MOVABLE ALONG THE ARM TO UNLOAD IT AT A PREDETERMINED RATE, A DISCHARGE OPENING AT THE BOTTOM OF THE HOPPER THROUGH WHICH MATERIAL IS ADAPTED TO BE DISCHARGED AT A RATE PROPORTIONAL TO THE UNLOADING OF THE ARM, A GATE OPERABLY CONTROLLING THE SIZE OF THE OPENING, A CONTROLLER RESPONSIVE TO AN ERROR VOLTAGE, ESTABLISHING A SIGNAL FOR CONTROLLING SAID GATE, A DIFFERENTIAL TRANSFORMER FOR APPLYING AN ERROR VOLTAGE ACCORDING TO THE DIRECTION AND MAGNITUDE OF MOVEMENT OF THE ARM TO THE CONTROLLER, A POWER RELAY OPERABLE IN ACCORDANCE WITH THE SIGNAL FROM SAID CONTROLLER TO EFFECT OPERATION OF THE GATE, MEANS FOR RENDERING THE DIFFERENTIAL TRANSFORMER INEFFECTIVE, WHEN THE HOPPER IS SUBSTANTIALLY EMPTY, MEANS ACTUATED WHEN THE HOPPER IS SUBSTANTIALLY EMPTY FOR REFILLING THE HOPPER, AND MEANS FOR ESTABLISHING A SIGNAL FROM SAID CONTROLLER MAINTAINING THE GATE IN A PREDETERMINED POSITION DURING REFILLING OF THE HOPPER.