Method and device for synchronizing motion for insert feeders in an insertion system

In an envelope inserting machine wherein a plurality of enclosure feeders are used to feed documents to a chassis, wherein each enclosure feeder has a releasing device to release enclosure documents, one at a time, and the chassis has a chassis driving device to drive a chassis transport in order to gather the released documents before the documents are collated for insertion, a method of synchronizing motion in an operational cycle between the chassis driving device and each of the releasing devices by using a plurality of encoding devices to obtain actual displacement amounts of the chassis driving device and each releasing device as a function of time, wherein said operational cycle has a number of commanded positions for defining motion profiles of each releasing device relative to the chassis driving device, said method comprising the steps of:

• 1) obtaining the transformation function for displacement mapping from the chassis driving device to each releasing device at each commanded position;
• 2) obtaining a first displacement of the chassis driving device;
• 3) obtaining a value of the transformation function corresponding to the first displacement;
• 4) displacement mapping the fist displacement to the respective releasing device according to the value of the transformation function obtained in step 3 in order to obtain a second displacement for the respective releasing device;
• 5) obtaining an actual displacement of the respective releasing device;
• 6) comparing the actual displacement to the second displacement to obtain the discrepancy therebetween;
• and
• 7) adjusting the motion of the respective releasing device so as to eliminate that discrepancy.

An apparatus for synchronizing motion in an operational cycle between a chassis driving device and at least one releasing device in an envelope inserting machine by using encoding devices to obtain actual displacement amounts of each movement mechanism as a function of time, wherein said operational cycle has a number of commanded positions for defining motion profiles of each releasing device relative to the chassis driving device, said device comprising:

• a first encoding device for obtaining the actual displacement of the chassis driving device;
• a processing device for calculating the theoretical displacement of the each releasing device based on the corresponding profile thereof and the actual displacement of the chassis driving device in order to control the movement of the respective releasing device;
• a plurality of second encoding devices, each for obtaining the actual displacement of one releasing device;
• a comparison device for obtaining the discrepancy between the actual displacement and the theoretical displacement for each releasing device;
• and
• a controlling device to adjust the movement of each releasing device so as to substantially eliminate the discrepancy in order to synchronize the motion of the chassis driving device and each releasing device.