| 摘要 |
<p>1474622 Making cylindrical plastics sleeve; searing OWENS ILLINOIS Inc 24 April 1974 [25 April 1973] 50892/76 Headings B5A and B5K A cylindrical sleeve of plastics material is made by wrapping a sheet around a mandrel with the ends of the sheet overlapping, directing hot air between the overlapped ends to soften their facing surfaces, diverting the air away from the ends after softening has occurred, and finally pressing the ends into engagement to form a longitudinally extending seam by means of a sealing bar. The sleeve thus formed may be used in a process and apparatus for the manufacture of containers as disclosed in Specification 1,474,621. In the above mentioned application rectangular blanks are cut from a continuous sheet, separated, and fed to an assembly for making sleeves. The sleeves are transferred to a series of mandrels which form a station at which discs are applied to the ends of the mandrels. The mandrels subsequently pass a heating station, a station at which the discs are sealed to the ends of the sleeves which have been heat shrunk on to the mandrels, a station at which the containers thus formed are removed from the mandrels and rimmed, a pre-heating station, before returning to the sleeve applying station for a new cycle (see Fig. 5, not shown). In the preferred embodiment, the leading end of a blank 18 (or 118) is held by a vacuum slot 35 on a rotating mandrel 31 (131), rotation of the mandrel through 540 degrees causing the blank to wrap around the mandrel with its ends overlapping as in Fig. 8. During the wrapping operation the blank is held firm against the mandrel by a roller 436 and at the end of the wrapping operation hot air is directed from an elongated nozzle 427a (427) between the overlapped ends. Finally the hot air is diverted and a cold sealing bar 429 forwarded to effect a seal. A series of mandrels are located on a rotating turret and after a sleeve has been formed on each mandrel the turret moves the mandrel to a path coinciding with the path of mandrels upon which the sleeves are shrunk to shape. The nozzle 427 associated with each mandrel 131 is located at the upper end of a vertical hot air duct 428 and has an air diverting opening 427b selectively opened and closed by a pivoted cover 428 actuated by a spring biased link system 428h actuated by a follower 428m which runs around a fixed cam 428n. Each roller 436 and sealing bar 429 is mounted in a carriage assembly 435 carried at the end of a forwardly spring biased piston rod 430 the rear end of which engages a fixed cam 430b through a cam follower 430a. The roller is biased forwardly of the bar relative to the carriage assembly by a spring 437 so that when the carriage assembly is first forwarded only the roller contacts the sleeve and when the assembly is further forwarded the pressure of the roller is increased and the sealing bar is brought into operative contact with the sleeve.</p> |
