| 摘要 |
<p>1,085,574. Measuring tension electrically. S. HEIM. Feb.10, 1965 [Feb. 25, 1964], No. 5875/65. Heading G1N. [Also in Division G3] The tension of a moving yarn or tape is measured by periodically deflecting the yarn by a predetermined distance from a straight path and measuring the force required to cause this deflection. In one embodiment, the yarn 17 passes fixed guide pins 18 between which it is contacted by a ceramic member 16 mounted on a Piezoelectric crystal. The crystal is itself mounted at one end to a cantilever arm (shown in end section at 14) the support 13 of which is oscillated at e.g. 50 or 60 c.p. s. by a diaphragm 11 driven by an A. C. energized moving coil and magnet system, Fig. 1 (not shown). The output from the Piezo-electric crystal is an alternating voltage, the peak value of which is determined by the tension in the yarn. The signal also contains a noise component which may be eliminated by damping the crystal or by electrical filters. In modifications, the guide pins may be oscillated instead of the crystal, the oscillatory movement may be obtained by Piezo-electric, magnetostrictive, or electro-static transducers, and the Piezo-electric crystal may be replaced by an electromagnetic force transducer. The output from the measuring device may be compared with a reference signal to control yarn tension, a break in the yarn can also be detected to shut down a machine.</p> |
