System for accurately positioning operations on conveyed products

In a process wherein products are conveyed on a conveyor and one or more operations by operating devices occurs along the path of the conveyor, such operations being turned "on", i.e. started, by an electrical pulse to the operating device, such operations occurring on each of a series of moving products under the control of the electrical pulses as the products pass by the operating devices, and in which the operating devices have compensation times for "on" cycling, so that the speed of movement of the product, i.e. the conveyor speed, will affect the location on the product at which the operation actually starts, a method for achieving better accuracy in the positioning of these operations on the products, comprising:

• storing in the computer information identifying desired positions on the products where the operations are to be located, including a begin point for each operation on the products,
• storing in the computer known compensation times for each of the operating devices positioned along the path of the conveyor in the process,
• detecting the position of each product as it moves along on the conveyor at least at one location in advance of the operating device, using a product sensor connected to the computer,
• prestoring in the computer a distance between the product sensor and an operating device,
• from the position of the product as noted with the product sensor, monitoring the position of the product and keeping track in the computer of the location of the product as it moves with the conveyor,
• with the computer, performing calculations in advance of each product's reaching the operating device, including calculating at least an "on" compensation distance for the operating device equal to the known and prestored device "on" compensation time multiplied by current speed of movement of the conveyor as determined by the computer, and calculating a first "on" action position or pulsing position by subtracting the calculated "on" compensation distance from the position of the operating device and taking into account the desired begin point for the operation on the product, which is stored in the computer,
• performing said calculations just before the product reaches the operating device, so that conveyor speed information is essentially current for the calculations, in the event of occasional changes in the speed of movement of the conveyor,
• with the computer, sending an electrical pulse to the operating device to initiate an "on" cycle of the device when the product reaches said first "on" action position.

In a process for applying glue to paper as it is moved along on a conveyor using a glue dispenser which is turned "on", i.e. started, by an electrical pulse to the operating device, such glue application occurring on each of a series of moving sheets of paper under the control of the electrical pulses as the sheets of paper pass by the glue dispenser, and in which the glue dispenser has a compensation time for "on" cycling, so that the speed of movement of the paper, i.e. the conveyor speed, will affect the location on the paper at which the operation actually starts, a method for achieving better accuracy in the positioning of the glue application on the paper sheets, comprising:

• storing in the computer information identifying desired positions on the sheets of paper where the glue applications are to be located, including a begin point for each glue application on the paper sheets,
• storing in the computer a known compensation time for each glue dispenser positioned along the path of the conveyor in the process,
• detecting the position of each sheet of paper as it moves along on the conveyor at least at one location in advance of a glue dispenser, using a paper sheet sensor connected to the computer,
• prestoring in the computer a distance between the paper sheet sensor and the glue dispenser,
• from the position of the paper as noted with the paper sheet sensor, monitoring the position of the paper sheet and keeping track in the computer of the location of the paper sheet as it moves with the conveyor,
• with the computer, performing calculations in advance of each paper sheet's reaching the glue dispenser, including calculating at least an "on" compensation distance for the glue dispenser equal to the known and prestored glue dispenser "on" compensation time multiplied by current speed of movement of the conveyor as determined by the computer, and calculating a first "on" action position or pulsing position by subtracting the calculated "on" compensation distance from the position of the glue dispenser and taking into account the desired begin point for the glue application on the paper, which is stored in the computer,
• performing said calculations just before the paper reaches the glue dispenser, so that conveyor speed information is essentially current for the calculations, in the event of occasional changes in the speed of movement of the conveyor,
• with the computer, sending an electrical pulse to the glue dispenser to initiate an "on" cycle of the glue dispenser when the paper reaches said first "on" action position.