Automatically controlled numbering machine

In an offset press comprising:

• (a) a printing machine;
• (b) a delivery machine cooperatively arranged relative to the printing machine for receiving the printed material discharged therefrom and delivering it to a point of deposit, said delivery machine including driving means and picking-up devices associated to said driving means for gripping the material discharged from the printing machine;
• and
• (c) a numbering assembly comprising;
• a numbering machine cooperatively arranged on a shaft relative to the delivery machine to serially number the printed material passing therethrough, said numbering machine including printing wheels having serial numbers thereon, a pawl for selectively stepping wheels each time a number is to be impressed upon a sheet of printed material and a stop for actuating said pawl at each passage of a sheet of printed material,
• an impression roller positioned beneath the numbering machine in cooperative relationship therewith;
• and
• a control assembly for instantaneously deactuating the numbering machine upon stopping of the press or in the absence of printed material to be numbered to avoid the printing wheels from being inadvertantly stepped several units forward, and for automatically reactuating the same when printed material is supplied again,
• the improvement wherein said control assembly comprises:
• (a) a first electrical circuit comprising a detection device responsive to the presence and absence of gripped material into the delivery machine, a first, normally open switch, and a solenoid all connected in series, said first circuit also comprising a relay mounted in parallel to the solenoid,
• said detection device closing said first circuit when printed material is normally supplied and opening the same when printed material is missing, said first switch closing the first circuit for a short period of time at each rotation of the shaft on which is mounted the numbering machine, said relay closing a second electrical circuit for a predetermined period of time each time it receives an electric impulsion from the first switch, said first switch also actuating the solenoid which in turn actuates mechanical means which brings the stop of the numbering machine in operative position into the path of the pawl so that the number to be printed, be stepped each time a sheet of printed material passes through the numbering machine;
• (b) said second electrical circuit comprising a second, normally closed switch, the above mentioned relay and the above mentioned solenoid, said relay when actuated, closing the second electrical circuit for a predetermined period of time which corresponds to the time necessary for the shaft to complete a rotation and to close again the first switch of the first circuit, said second electrical circuit being therefore closed and the solenoid kept in actuating position during said predetermined period of time,
• (c) said mechanical means actuated by the solenoid comprising:
• a main lever mounted on a central pivot and permanently provided with an oscillary movement generated by a main cam mounted on the numbering machine shaft;
• a stop lever operated by the solenoid and supporting on its axis the stop used for camming the pawl of the numbering machine;
• blocking means operated by the solenoid for limiting the amplitude of the oscillations of the main lever, and
• first and second blocking levers for holding both ends of the stop lever on which is mounted the stop when the latter is in operative position, said first blocking lever being permanently provided with an oscillary movement generated by another cam mounted on the numbering machine shaft at an angle with respect to the main cam, to give the above mentioned delay to the stop before being moved out of the path of the pawl, said second blocking lever being connected to the main lever and actuated by said main lever when the oscillations of this main lever are not limited by the blocking means,
• whereby, as long either the first or second electrical circuits are closed, the solenoid is actuated and causes both the stop lever to be tilted about its axis and to hold the stop in operative position and the blocking means to limit the oscillations of the main lever, said tilting of the stop lever being delayed when the circuits are closed, by the first blocking lever which releases the stop lever only when the other cam moves the first blocking lever up, and second blocking lever being positioned inside the machine in such a manner that it may engage the stop lever when the same is tilted in operative position and hold it in this position even when the first blocking lever is released by the other cam at each rotation of the machine shaft.