Patent GB-829456-A (GB)
Title: Improvements in and relating to an automatic machine for packing liquid or other products
IPC: B65B9/02
Filed: 1957-08-01
Abstract: 829,456. Packaging machines. SOC. D'ETUDE ET D'APPLICATION INDUSTRIELLE DE BREVETS, S.E.A.B. Aug. 1, 1957 [Aug. 10, 1956], No. 24430/57. Class 94(1). [Also in Group XI] A machine, Fig. 2, for packaging liquid, pasty or powdered products, comprises means for bringing two bands Q. R, of plastic material together about a supply tube C; upper and lower reciprocating presses D and E for repectively forming longitudinal side seams S. T, Fig. 1, and transverse seals V, to form pockets P1, P2, in the plastic material ; and a pulling clamp F for displacing the bands Q, R, by one pocket length each time the presses D and E are opened.  Pulling clamp F.-This comprises two pivoted jaws 69, 70, provided with rubber liners 71, 72, and adapted to oscillate to and from each other through ram controlled toothed sectors 77, 78. The clamp F derives its pulling action from a ram device G the stroke of which is predetermined by an adjustable electrical contact device 104 co-operating with a contact 106 on the clamp F. Downward motion is derived from a compressed air source and upward motion is derived through a liquid mass acted on by the compressed air source. The liquid mass is present in order that when the contacts 104, 106, meet to close a valve in the liquid supply system the entrapped liquid will ensure a definite stoppage of the clamp in its extreme lower position. Sealing presses D and E.-The [motions of the sealing presses D and E are controlled by pneumatic rams or fluid motors 23, 49, and the sealing operations may be by high-frequency currents, the circuits to which are completed through contacts that close on the presses reaching their operative positions. The upper press D has a groove to accommodate the tube C and the lower press E, effecting the transverse seals V, has a slight projection extending from the welding electrode on one of its plates, this projection serving to produce a line U, Fig. 1, of reduced resistance on the transverse welds and along which the bags P1, P2, may be separated. Impulse welding or heat welding by resistors may be used instead of the high frequency welding. Supply tube C.-The tube C is of rigid plastic material adjustably held by a chuck 15. At the lower end of the tube are two platinum contacts 17a, Fig. 10, arranged such that when the substance to be packed reaches a height sufficient to form a bridge between these two wires a valve 16 in the supply source is closed to stop the supply. Inflated doses.-To produce bags P1, P2, that are put under tension by the product to be packed the pulling clamp F in its upper position must close at a point below the level of the contents as controlled by the wires 17a. Then, when the lower press E eventually closes, the volume of the product pushed aside by the electrodes of the press E cannot escape upwards because of the closed clamp F and this creates the necessary pressure for putting the container under tension. Soft doses.-It is also possible to obtain doses without internal pressure by forming in the rubber liners 71, 72, of the clamp F, recesses which permit the volume of the product pushed aside by the electrodes of the press E to rise up in the container. Alternatively the means supplying the tube C may be controlled by a metering pump. Modifications.-Instead of two bands Q, R, a single band folded upon itself can be used. Also the machine may be designed to use a larger pair of independent bands or a single larger band capable of being drawn into a number of parallel tubular sections into each of which will depend a tube C. If inscriptions appear on the finished bands, the unwinding of the bands could be controlled, in known manner, by a photo-electric cell which would ensure that the inscriptions are centred on the bags.