Insert machine
The present invention discloses an improved insert machine for inserting flat material into an open pocket and, more particularly, to a straight line insert machine employed for printed matter such as newspapers. The machine includes an all-electronic control system for controlling machine functions. The control system includes at least one central control computer running under software control and a plurality of network controllers, all coupled together via a controller area network (CAN) bus. Electronic control messages for controlling machine elements are sent among the computers and controllers using a novel message protocol to enable both broadcast messages and individual messages to be employed.
1. A variable vacuum control system, comprising:
a vacuum source and an air source;
a movable suction cup coupled to the vacuum source and an air source for periodically grabbing and removing a flat item from a bottom of a stack of flat items held in a hopper positioned above the suction cup by means of vacuum suction, the hopper having a slanted bottom wall and a front wall with a jogger which moves backward and forward to keep the flat items aligned in the hopper;
a variable speed rotating drum for receiving each fiat item after removal, the drum moving at a variable speed relative to the hopper;
at least one sensor/encoder associated with the drum for sensing the speed and position of the drum relative to the hopper and generating speed and position signals corresponding thereto; and
a servo drive coupled to the sensor/encoder to control at least one vacuum/air valve,
whereby, upon detecting a change in speed of the drum, the servo drive automatically alters control signals to the valve to alter the application of vacuum and air to the suction cup corresponding to the change in speed of the drum.
2. The system of claim 1 , adapted for use in a machine for inserting flat items into folded items.
3. The system of claim 2 , wherein the machine is an insert machine for automatically inserting flat paper items into open sides of partially folded newspapers.
4. The system of claim 1 , wherein the sensor / encoder comprises an encoder for generating timing signals as the drum moves.
5. The system of claim 1 , wherein the servo drive includes a servo control and memory storing data representative of (a) a plurality of speeds of rotation of the drum; and (b) predetermined vacuum and air start and stop times for each speed, each time corresponding to an angular movement of a point on the drum relative to a fixed reference point for each speed.