Patent GB-1165569-A (GB)
Title: Twin-Line Machine for Heat Sealing Webs of Plastics Material.
IPC: B29C65/00
Filed: 1966-12-07
Abstract: 1,165,569. Seaming non-metallic sheet material; making bags. WINDMÍLLER & HÍLSCHER. 7 Dec., 1966 [28 Jan., 1966], No. 54717/66. Headings B5D and B5K. A twin line machine for transversely heat sealing and severing intermittently advanced flattened tubular webs or longitudinally folded webs of plastics material to produce bags is characterized in that bags of one length from one web can be produced on one line of the machine whilst bags of a different length from a second web are produced on the other line of the machine by separate heat-sealing and severing tools or bags may be produced from a wider web by a continuous tool which extends across both lines of the machine. If separate bags are produced on each line of the machine, on one line the web of plastics material passes from a supply roll 1a braked by a strap brake 2a around rollers 3a, 4a, between a roll 8a and associated pressure rolls 9, around a dancer roll 10a, around a roll 11a and between feed rolls 12a. A roll 5a and a dancer roll 7a are not used. When this line of the machine is switched on, a motor 13a is started to drive the roll 8a at a controlled speed and cause the dancer roll 10a to be lowered so that a control arm 14a secured to a lever on the roll 10a is moved into the range of a detector 15a. This produces a signal to lift a brake 16a for the rolls 12a and operate a clutch 17a to couple the rolls to a continuously operating operating motor 18a. Simultaneously, a millimeter pulse generator 19a applies pulses to a preset counter (not shown) and when the preset count corresponding to the desired bag length has been counted, the pulse counter opens the clutch 17a and applies the brake 16a to stop the rolls 12a. A solenoid unit 20a moves a heat sealing and severing member 21a downwardly to act on the web until the set time of an adjustable timer has expired. The member 21a is moved upwardly and a solenoid 22a is energized for a short time, controlled by an adjustable timer, so that a lever 23a pivots to cause a lower conveyer belt 24a to be urged against an upper belt 25a so that the bag-section is moved on to a delivery table 26 to contact an adjustable stop 27a. The belt 25a is driven by a motor 28a which may be provided with a clutch and brake so that the belts 24a, 25a operate in synchronism with the feeding cycle of the machine. The next feeding cycle begins when the arm 14a moves again into the range of the detector 15a. If the web has printed control marks thereon, then, instead of using a preset pulse counter, the marks are detected by a photo-electric cell 31a which applies the brake 16a. The second line of the machine comprises similar parts designated by similar reference numerals but with suffix b and operates in the same manner as the first line with the exception that a roll 5b and a dancer roll 7b are used rather than the roll 8b and the dancer roll 10b to prevent unnecessary stressing of the common shaft on which the dancer rolls would be mounted if only one pair were provided. If the machine operates as a double-width single line machine, the web is unwound from a roll rotatably mounted on a shaft and passes around the roller 3a or 3b, around rollers 4b, 4b, between mechanically-coupled rolls 5a, 5b driven by the motor 13b and pressure rolls 6 arranged spaced apart across the entire width of the machine, around dancer rolls 7a, 7b, between mechanically-coupled rolls 8a, 8b and pressure rolls 9 which have been lifted out of engagement, around the dancer rolls 10a, 10b and around the rollers 11a, 11b to mechanically-coupled feed rolls 12a, 12b. An electrically-controlled cutch 32a of the motor 13a is operated so that the rolls 8a, 8b are free running. The pivoted levers of the rolls 7a, 7b are connected to those of the rolls 10a, 10b by a spring 33 so that both units are raised in unison when the rolls 12a, 12b are started. When the web has been fed by a bag length and stopped, the solenoids 20a, 20b are simultaneously energized and the members 21a, 21b remain in contact with the web for the same time. The members 21a, 21b are provided with a continuous heat sealing and severing bar.