Grape press with fast and slow drive motors - having control circuit connected to pressure sensor mounted on pressure plates

摘要

A grape press has two pressure plates with central bosses which are internally threaded to travel on a threaded spindle which is rotated by a reduction gear so that they are forced together to compress the grapes. The gears are driven by two motors for high and low speeds. These motors are operated by a control circuit, controlled in turn by a pressure sensor mounted on the pressure plates. The control circuit operates a system of relays in the power supply lines to the motor coils. The circuit includes a timing arrangement operating between two threshholds, with a control transistor with its base fed from a constant current resistance and diode system. A variable potentiometer is included in the system to adjust the range of operation.