Device for controlling the advance and the positioning of envelopes in an insertion machine

A control device for controlling the advance and the positioning of envelopes in an insertion machine, the device comprising transfer means for transferring empty envelopes along a transfer path coupled to the inlet of an insertion station, and ejection means for ejecting envelopes filled at the insertion station, said transfer means and said ejection means being operated during an ejection and feed sequence, which sequence forms a part of a set of control sequences for the machine with the sequences being defined relative to one another for each insertion cycle, the device further including:

• a stepper motor coupled in common to said transfer means and to said ejection means in order to control them simultaneously;
• a clock circuit generating clock signals for each cycle and in synchronism with the progress of all of said sequences;
• an envelope presence detector at an intermediate point along said path;
• and
• a circuit for controlling and governing the speed of said stepper motor, said circuit being coupled to said clock circuit and to said envelope presence detector in order to receive output signals therefrom, and being equipped firstly with first detector means for detecting a first indicator of said ejection and feed sequence on a first defined clock signal in order to control motor drive and trigger a first or "advance" drive stage on the appearance of said first indicator, and secondly with first governor means for governing said advance stage by detecting motor steps, said first governor means being triggered by the output signal from said envelope presence detector indicating that the envelope has finished going past said intermediate point in order to detect a first determined number of motor steps defined relative to the distance between said intermediate point and the inlet of the insertion station and to cause the motor to stop when said first number of detected motor steps is reached.