GB1438951A - Packaging - Google Patents

Abstract

1438951 Packaging machines; endless conveyers F D C BATE 4 May 1973 [29 June 1972] 30399/72 Headings B8C and B8A [Also in Division B5] In apparatus for shrink-wrapping articles such as rolls R of wall-paper, thermoplastics film is drawn from two reels 14, 16 to form super-posed layers which are turned through 90 degrees to follow stepped paths 30, 32, 34, transverse heat sealing and severing being performed in housing 174 to laterally form openended tubes which are opened by devices on article carriers 38 moving on adjacent stepped paths 40, 42, 44, 46, 48, 50, each carrier also having means for pushing its article into an opened tube 170, the packages so formed then passing through heat-shrink tunnel 24. Alternatively, a single centre-folded film may be used to form the tubes 170. Film feed.-Film from reels 14, 16 passes over inclined rods 58, 62 and then to guide rollers 98, 100 via tensioning rollers 66, 68, 70, 72, 74, of which rollers 72, 74 tension the film by gravity, and corresponding lower rollers 82, 84, 86, 88, 90. The superposed films then pass over a resilient conveyer 18 (Fig. 4) comprising heatresistant rubber blocks 132 on endless chains 120 running beneath a belt 134 of polytetrafluoroethylene. Seal and sever device (see Fig. 7).-A metal head with heated sealing and severing wires is mounted on a carriage resting on rollers for horizontal reciprocation on conveyer 18. The rollers steady the films as head 150 is lowered to seal and sever the films during forward motion of the carriage. Reciprocation of the carriage and depression of head 150 are controlled by cams 178 and 290 respectively on shaft 176. Cam 178 actuates a slider 182 on guides 186 to rock levers 190 about pivot 192. A frame 204 attached to levers 190 is reciprocated on rails 200, 208 whereby the carriage is reciprocated through pin and slot connections with levers 220 and slider 206 of the frame 204. Cam 290 depresses head 150 through a bell-crank lever and frame 310 along which the carriage is movable on trolleys 314. Exact synchronization between carriage and conveyer belt 134 is achieved by adjusting the fulcrums of levers 220 by screw 234, any relative motion between carriage and belt being shown by an indicator disc on the shaft of a carriage roller. The severed tube 170 is flicked forward by a rapid reverse rotation of a carriage roller as head 150 is raised. The adjustable stroke of head 150 allows different sizes of package to be made. Article conveyer 36 comprises endless chains 330 bearing carriers 38 of which trays 346 are slidable transversely of the conveyer or rods 345 as the slider 354 of each carrier follows a cam track 372 (Fig. 24) beneath the conveyer. Tube opening devices 386 (Fig. 15) are mounted on each carrier 38 and consist in each case of a rod 406 fixed to the carriers to enter and hold a tube, and rods 408, 410 fixed to separate plates 394 on rods 388, 390, whose rotation, thus rotates rods 408, 410 to open the tube. A trunnion 420 slidable on shaft 334 of each carrier has a spigot engaging a helical groove in the end of shaft 388, and a slider 424 entering a cam track 426 beneath the conveyer. Movement of the carriers with conveyer 36 results in relative motion between sliders 354 and 424 to give rotation of shaft 388 against spring-loading; shaft 390 being oppositely rotated by similar means. Articles are then inserted into the tube 170 by a pusher block actuated by fixed cams beside conveyer 36. The ends of each package are closed by the shrinking effect of heatshrink tunnel 24. End sealers may be provided before tunnel 24 if desired. As an alternative tube opening device, movement of a slider on carrier 38 in response to track 426 acts on a spring-loaded bell-crank lever to raise cranked opening arms pivotal about a horizontal axis parallel to conveyer 36, fixed rods holding the tube bottom as before. Again, air pressure from a nozzle may be used to open the tubes.