Patent ID: 8453420

Claim:
A film wrapping/packaging apparatus, comprising: a film dispensing carriage assembly; a spindle mounted upon said film dispensing carriage assembly and supporting a roll of wrapping/packaging film wherein the wrapping/packaging film dispensed by said film dispensing carriage assembly from the roll of wrapping/packaging film is to be used for wrapping a load to be packaged; first and second drive rollers driving the film from the roll of wrapping/packaging film mounted upon said spindle toward the load to be wrapped and packaged; first and second target rollers, having sensor targets respectively mounted thereon and disposed upon opposite upstream and downstream sides of said first and second drive rollers, as considered in the direction in which the film is being dispensed from said spindle and toward the load being wrapped and packaged, respectively rotated at speeds corresponding to the speed of the film at the respective locations of said first and second target rollers; first and second proximity sensors disposed adjacent to said first and second target rollers detecting the presence of said sensor targets respectively disposed upon said first and second target rollers each time each one of said first and second target rollers completes a revolution as the wrapping/packaging film is conducted past said first and second target rollers and generating signals indicating said detected presence of each one of said sensor targets upon each one of said first and second target rollers; and a programmable logic controller (PLC) mounted upon said film dispensing carriage assembly receiving said signals from said first and second proximity sensors and calculating the amount of pre-stretch imparted to the wrapping/packaging film as a function of the difference between the speeds of the wrapping/packaging film as the same respectively passes each one of the first and second target rollers.