Article feeding and discharging device

A material supply and discharge apparatus comprising:

• a hopper having a receptacle port for materials at an upper end thereof and a discharge port for the materials at a lower end thereof;
• a material supply mechanism disposed upwardly of the hopper, the mechanism causing the materials to be dropped from the reception port into the hopper;
• a shutter turnably mounted so as to open and close the discharge port relevant to the hopper, the shutter being driven to be opened and closed so as to be released downwardly under a load in the gravity direction of the materials when the materials are dropped from the material supply mechanism after the discharge port has been closed in order to temporarily hold the materials in the hopper;
• a motor linked with the shutter in order to drive the shutter to be opened and closed, a holding current being applied during closing of the shutter, thereby the shutter imparting to the shutter a torque against a force released downwardly by the load in the gravity direction of the materials;
• and
• a shutter control portion for setting the hold current applied to the motor from the start time for loading applied to the shutter caused by the materials dropped from the material supply mechanism to a predetermined period, to a first hold current value capable of applying to the shutter a torque bearing a shock when the materials are charged, and setting a hold current applied to the motor from after an elapse of the predetermined period to the start of discharge from a discharge port of the hopper to a second hold current value smaller than the first hold current value capable of applying to the shutter a toque against a force released downwardly under a load in the gravity direction of the materials.