Abstract: An elevator for adjusting the elevation of a code reader of a high speed mail sorting machine. The elevator is powered by a reversible DC electric motor which operates an extensible and retractable linear actuator. The actuator connects with a platform on which the reader is mounted. A control circuit for the motor includes a digital comparitor which compares the desired elevation of the reader with the actual elevation sensed by a potentiometer. A transistorized motor drive circuit controlled by the comparitor applies current to the motor in opposite directions to cause extension or retraction of the actuator, depending upon whether the reader is below or above the desired elevation. Upper and lower limit switches limit the range of movement of the reader.

Abstract: An improved envelope tracking and control system for a mail sorting machine of the type which reads a sorting code imprinted on each envelope and deposits the envelope in the proper sorting bin by deflecting a diverter gate associated with the bin. Each diverter mechanism has two sets of photo sensors which sense the presence of an approaching envelope. Tracking circuitry processes the sort code obtained from the envelope and transfers the processed data to the tracking circuit for the next diverter if the data does not coincide with a code that has been preassigned to the diverter. The processed data is held in a latch circuit and is passed on only if the envelope is sensed by the second set of photo sensors. If there is coincidence of the data, a one shot pulse applied to a solenoid deflects the appropriate gate for a predetermined time period that avoids possible damage to the solenoid or to the circuit components.