| 摘要 |
<p>PURPOSE:To decrease the number of the component parts with elimination of the space limitation and thus to reduce the cost by detecting the current ripple of the DC motor which drives the reel stand and securing an automatic stop with the ripple componet turned to zero by the stoppage of the motor at the tape terminal. CONSTITUTION:Supply reel stand 1 and take-up reel stand 2 are driven by pulley 8 stuck to DC motor 7 and via idler 9. The serial circuit of capacitor 14 and resistance 15 is connected between movile contacts 11c and 12c of switches 11 and 12 which change the turning direction of motor 7, and automatic stop command circuit 16 is connected to the junction between 14 and 15. Based on the command given from circuit 16, the electric conduction is given to electromagnetic solenoid 17. As motor 7 adapts a DC motor, the ripple occurs to the current waveform at point A by the rectifier while the motor is turning. When the ripple component becomes zero at point B where the DC component is removed via capacitor 14, i.e., when the turn of the reel stand stops, command generation circuit 16 generates the automatic stop command to make solenoid 17 conduct and then to vide an automatic stop to the device.</p> |
