| 摘要 |
A weigh-on-the-fly WOF module for weighing a mail piece as it is being sorted by a mail sort machine. The piece is delivered to entry pinch rollers in the WOF module which, in turn, deliver the piece into pinch at an acceleration roller. The thickness of the piece is measured the pinch at the acceleration roller is adjusted to reduce drag on the mail piece during acceleration. The acceleration roller is driven by a constant torque motor at a first known or measured velocity V1 which is increased to second known or measured velocity V2 when the mail piece arrives. The time of acceleration from V1 to V2 is measured. Once the velocities and the time of acceleration are known, the weigh of that particular mail piece can be calculated using the formula: F=ma wherein F=force or torque m=mass or weight; and a=acceleration or (V2−V1)/time.
|
