Patent GB-599100-A (GB)
Title: Improvements in or relating to devices for detecting and distinguishing imperfect workpieces in automatic machines
IPC: B07C5/08
Filed: 1945-09-13
Abstract: 599,100. Wrapping-machines. KIDD, D. B., and MOLINS MACHINE CO., Ltd. Sept. 13, 1945, No. 23611. [Class 94 (i)] [Also in Groups XXXII and XXXVII] A device for detecting imperfect workpieces in automatic machines comprises an electro-magnet having double windings whose magnetic fields oppose one another when current is passing through both windings and wherein on the operation of the detector the current through one winding is stopped thereby causing the core of the magnet to be magnetized and stop the machine or separate or otherwise distinguish the imperfect from the perfect workpieces. Fig. 9 is a circuit diagram for a form of the invention as applied to a well-known type of automatic cigarette packing machine having a detector 43 to detect the absence of a cigarette from a batch, a detector 44 to detect the absence of a piece of metal foil unwrapped round the cigarettes, the foil forming part of an electric circuit, a detector 48 to detect failure to feed a slide on to a packet conveyer where it receives the cigarettes, detectors 51, 52 operating on failure to supply one of two inserts respectively to the packet, and a detector 53 to detect the absence of a completed package at the entrance to the delivery section, Relays R', R<2>, R<3> are spaced around the periphery of a rotating disc (see Group XXXVII) and each comprise two coils, both of which are connected at one end to a positive supply line R from a D.C. generator 70, and one of which is connected at the other end to earth, the other pole of the generator being also earthed. During normal operation of the machine, the second coils of the relays R<1>, R<2>, R<3> are also earthed through the detectors 53, 43, 44 respectively, so that both coils are energised, the magnets thus being inoperative; a lamp 72 indicates that the generator is functioning properly. The operation of either of the detectors 53, 43 breaks the circuit of the corresponding relay R<1>, R<2>, the magnet of which is thus energised to pull over a spring contact (see Group XXXVII), and energise a solenoid 63, one pole of which is connected to the supply line R, by earthing the contact 28, the solenoid acting to displace a stripper at the delivery station, thereby allowing the faulty package to pass to a second stripper which delivers it into a waste box. The relay R<2> also operates a signal lamp 73 through contacts 74, 75. The operation of either of the detectors 51 or 52 causes a bell 80 to ring, a rotary switch 27 operated by a cam 26 (see Group XXXVII) completing the closure of the detector circuit during the time a package is passing the detectors. The detector 48 operates to make a circuit and operate a solenoid 58 which stops the machine through a hammer and catch mechanism which declutches the machine from its driving pulley. The detector 44 operates to. break a circuit and energise the magnet of the relay R', which. through contacts 78, 79, operates the solenoid 58 to stop the machine, a second rotary switch 27 acting to keep the magnet non-energised except at the time a piece of foil should be in position to complete the detection circuit, the switch completing a circuit to earth through a coil of the relay in parallel with the detector circuit. The contacts 74, 75, 78 and 79 are operated by means of contact fingers 24 (see Group XXXVII). Specification 357,970 is referred to.