| 摘要 |
A piezoelectric element forms at least a part of a resilient vibrator which is firmly gripped at one end at a clamping point and is stressed by the tensile force of the thread at the other end, and which is prestressed substantially parallel to the stressing direction through a bearing surface acting at a point between its ends and rigidly connected to the clamping point. As a result, the piezoelectric element detects vibrations which are transmitted to the vibrator from its clamping point far less than vibrations which are transmitted to the vibrator through its free end by the tensile force of the thread. The transducer is therefore particularly suitable for installation in or on thread-processing textile machines. Its signal indicates not only the presence but also-with a moving thread-the travel of the thread, particularly when this thread is withdrawn overhead from a bobbin. |
