| 摘要 |
<p>963,258. Measuring electrically. J. S. RIERA. Aug. 9, 1960 [Aug. 14, 1959], No. 27564/60. Heading G1N. Defects in a thread are detected by causing the thread diameter to vary an impedance in series with a fixed impedance and an A.C. supply, rectifying and differentiating the voltage developed across the variable impedance and using the voltage developed to perform one or more of cutting the thread, indicating passage of the irregularity and stopping the machine. In Fig. 1, the thread passes between a condenser comprising a fixed plate 4 and a movable plate 3, both of which bear on the thread. When a defect passes between the plates of the condenser which is connected in series with an A.C. supply and a fixed resistor 5 its capacity varies. The voltage developed across it is rectified at 19 and differentiated at 21 so that only sudden variations in the thread are detected, amplified at 23 and used to operate a thread cutter 26. The same signal may operate an indicating device or be used to shut down a machine working on the thread. Condenser construction. (Figs. 2 and 3). The thread passes between a fixed steel plate 4 clamped in a groove in an insulating block 12 by screw 10 and diverging at 9 from the block and a spring steel plate 15 clamped at its end remote from the fixed plate by screw 16. The edge of plate 14 is bevelled to allow the thread to enter. Modifications. The voltage across the fixed instead of the variable impedance may be used and the impedance in series with the condenser may be another condenser or an inductance.</p> |
