Abstract: Apparatus is provided for applying a constant tension to a belt extending around first and second rollers by way of a parallelogram linkage connected to said second roller for moving said second roller to tension said belt. A lever arm is connected to the linkage and includes a weight adjustable along the lever arm.

Abstract: Apparatus for generating a belt tare compensation signal including a load cell in operative contact with a feed conveyor belt dividable into N equal segments. The output of the load cell is strobed each time the conveyor belt advances one sampled and a pulse train representative of the output of the load cell is generated. The pulse train is applied to a pulse counter if the output of the load cell is greater than a predetermined value and is applied to a minus counter if the output of the load cell is less than a predetermined value. At the end of a single revolution of the conveyor belt, a signal representative of the difference between the count in the plus and minus counters is generated. This signal is divided by N so as to generate a belt tare compensation signal which is representative of the average output of the load cell during a single non-loaded revolution of the conveyor belt.

Abstract: Apparatus for controlling the feed rate and batch size of the material feeder is disclosed. A signal generator computes the weight of material delivered by the material feeder and compares it to first and second presettable values. When the weight of material delivered by the feeder is less than the first presettable value, the signal generator enables a first pulse generator which generates a pulse train having a relatively high pulse repetition frequency. This pulse train is applied to a motor speed controller which causes the feeder to deliver material at a relatively high rate. When the weight of material delivered by the feeder reaches the first presettable value, the signal generator enables a second pulse generator and disenables the first pulse generator. The second pulse generator generates a pulse train having a pulse repetition frequency substantially lower than that of the pulse train generated by the first pulse generator.

Abstract: The endless belt of a gravimetric feeder is provided with a tracking and tensioning assembly which is mounted for rotation about a vertical axis. The assembly is also mounted for movement along said axis between operative and inoperative positions. In the operative position of the assembly, it tensions the belt and instantly corrects any tendency of the belt to move sideways. The assembly also maintains the inner surface of the belt clean by scraping the same when the assembly is in its operative position.