GB932949A - Yarn break detector - Google Patents

Abstract

932,949. Spinning processes; stop-motions. L. NAMENYI-KATZ. May 24, 1960 [May 25, 1959], No. 17678/59. Classes 120 (2) and 120 (3). In a method of detecting yarn breakages in textile machines, a beam of light is directed on to each yarn in turn and the light reflected from the yarn is caused to activate a photo-electric device adapted to inhibit an alarm signal. Presence of yarn withholds an alarm signal and absence thereof prevents operation of the inhibiting device and allows the signal to be produced. An alarm circuit may include a device which continues to operate the alarm after the beam has been moved to the next yarn. As shown in Fig. 1, which represents one station of a spinning frame, roving 16 passes through an eye 17 and an aperture 18 on a flyer arm 11, thence to a bobbin 14 rotatably supported on a reciprocating frame 15 and braked by a cord 19 and weight 20. A carriage 23, continuously travelling or traversing the length of a row of spindles 12, mounts a light source, e.g. a lamp and condenser lens 25, so as to throw a beam on to each yarn as the carriage passes it. Light reflected from each yarn passes through a lens 26 to a photoelectric device 27, e.g. a photo-transistor. A series of contact strips 28 are engaged by a travelling contact 29 on carriage 23 so that carriage circuits are electrically energized (to switch on the lamp and bring electrical circuits into operation) just before the carriage reaches each spindle and are de-energized sometime after the carriage has passed the spindle. The reflected light causes device 27 to deliver a signal to an amplifier 32, Fig. 2, the output signal of which operates an electromagnetic relay to close a normally open holding-contact RL1 and open a normally closed contact RL2 so that (a) coil RL remains independently energized from the power supply until contact 29 leaves strip 28 for the corresponding spindle, whereupon relay returns to inoperative condition and (b) engagement of an auxiliary contact 30 on carriage 23 with a fixed contact 31 (after carriage has passed the spindle and before contacts 28, 29 disengage) has no effect when yarn is intact. When breakage occurs, the relay remains in unoperated condition and contacts RL2 are closed so that an alarm circuit produces visual or audible signal. The alarm circuit is reset after the yarn is restored. An indicator may show which spindle requires attention and stop the spindle. A system capable of high-speed operation and independent of variation in room lighting, switching surges, and lamp failures comprises an oscillator to feed the source (whereby the light therefor is modulated) the amplifier being tuned to the frequency thereof, and a bi-stable multivibrator, separately set both to permit and to inhibit a relay-operated alarm, each connected to a Schmitt circuit, Figs. 1 and 4 accompanying the Complete Specification (not shown).