Patent ID: 8530762

Claim:
A method for weighing a moving, substantially flat article, comprising: receiving an incoming article having a first velocity; engaging the incoming article with an accelerator assembly so that the article moves in synchrony with the accelerator assembly with minimal slippage; providing a capstan servo motor having a shaft operatively coupled to the accelerator assembly so that the motor shaft and the accelerator assembly rotate in unison; providing a servo amplifier coupled to the capstan servo motor so as to form a closed-loop servo system for controllably driving the motor and for monitoring torque applied by the capstan servo motor; in the servo amplifier, commanding the capstan servo motor to a predetermined, constant command speed that is different from the first velocity of the incoming article; while the article is engaged with the accelerator assembly, acquiring a series of capstan servo motor torque sample data as the article moves along with the accelerator assembly, so that the captured torque data records torque applied by the capstan servo motor to change the article speed from the first velocity to the command speed; and processing the acquired torque sample data to determine a weight of the article without regard to actual speed of the article.