GB1337138A - Control network for a knitting machine - Google Patents

Abstract

1337138 Knitting machines STOP-MOTION DEVICES CORP 13 July 1971 [15 March 1971] 32838/71 Heading D1C In a knitting machine having at least one fault-detecting circuit a control network comprises a unidirectional power source and diode means between the power source and the circuit(s) shunted by a circuit element which when energised causes de-energisation of the machine drive. The detector may comprise a detector for broken yarn, or a described latch detector. Yarn and latch detectors may be arranged in two sets with a common power source. An individual fault-detecting circuit A, of which several may be arranged in parallel, comprises a switch 36-40 closed by a fault. A thyristor 66 is thus energised to light a lamp 48, by-passed by resistor 68. The control circuit includes diodes 75 in parallel with a relay 74, which when energised can stop the machine. The diodes provide a constant voltage drop, so that the current through the relay is constant despite lamp failure or several circuits being energised. In a modification (Figure 5 not shown) diodes (108, 110) are by-passed by a transistor (116) which when energised, deenergises a second transistor (96) and interrupts the current in a relay (100) in the motor circuit. In a modification (Figure 6 not shown) two sets of detector circuits are associated with the same relay (100). The latch detector comprises a coil spring 36 supporting an insulated probe 28. The spring has an axial insulated core 40. If the probe strikes a defective latch or an accumulation of fly, the spring is deflected to contact the core so that the lamp 48 is lit. The circuit is reset by depressing the lamp cover 50 against spring 56, so breaking contacts 54-58. The resetting switch may be omitted if the spring is of magnetizable material and can be held in contact with a permanent magnet core 40.