| 摘要 |
<p>A system and method detect the location of a workpiece (30) as it passes from a feeding mechanism (25) to a receiving pair of rollers (20). The system generally consists of a feeding mechanism (25) having a pair of feeding rollers, a pair of receiving rollers (20), a means (15; 65) for applying a fixed torque to the receiving rollers (20) causing the receiving rollers (20) to rotate, and a tachometer means (35) for monitoring the revolution speed of the receiving rollers (20). The means for revolving the rollers consists of a motor (15; 65), motor controller (40; 70) and a microprocessor (45) to program the motor speed or torque. A decrease in the revolution speed of the receiving rollers (20) indicates the workpiece (30) has been received by the receiving rollers (20). An increase in the revolution speed of the receiving rollers (20) subsequent to the decrease in speed indicates the workpiece (30) has been released from the feeding mechanism (25). <IMAGE></p> |
