| 摘要 |
<p>High-speed spooling machines for yarn or thread are subject to the difficulty that, if the yarn or thread should break between a yarn cleaning, that is, size sensing and cutting apparatus and the takeup spool, stray remnant filamentary pieces may occur due to operation of the cutter apparatus since the thread size sensing apparatus may provide an erroneous "cut" signal upon absence of any thread in the sensing field. To prevent such operation, a thread sensing element is interposed in the path of the thread being spooled which, upon break of thread, will provide a "no tension" signal which will be below a predetermined threshold level. This signal is then used to inhibit operation of the cutter, regardless of the output of the thread size sensing element. To permit proper operation of the sensing unit in spite of short-time failure to sense thread tension, the "off-size" signal is preferably stored for a predetermined period, for example one second, and applied with this delay to the cutter apparatus, so that short time loss of sensed tension is not overriden but complete yarn breakage will not result in cutting action.</p> |
