| 摘要 |
1,008,075. Package sealing devices. FARBWERKE HOECHST A.G., and BEBO-PLASTIK G.m.b.H. Sept. 7, 1962 [Sept. 7, 1961], No. 34408/62. Heading B8C. [Also in Division B5] A device for welding together superimposed layers of thermoplastic material, e.g. a cover to the peripheral rim of a foodstuffs container, comprises a welding element in the form of a heat-conducting diaphragm 1 fitted into a pressing element 3, 20 equipped with a cooling device and disposed between a heat transfer block 2 and a resilient counter member 5 to support the layers to be welded, the block 2 being axially displaceable independently of the element 3, 20. The pressing-and-cooling element comprises a head 3 and a neck 20 slidable in a guide 17. Borings 18 are provided in the neck 20 parallel to the axis thereof and at their upper ends are connected to an inlet and an outlet for a cooling fluid which circulates through a hollow space 22 in the head 3. In use, a filled container 15 with a superimposed cover 16 is suspended in a frame 7 and a shaft 23 is moved downwardly so that a disc 4, which may be latticed, thereon contacts the cover 16. The element 3, 20 is moved downwardly until the annular diaphragm 1, which may be made of copper-sheet, rests on the flanges to be sealed. A heat-storage block 19 and the heat transfer block 2, which may be made of copper or bronze, move into contact with the diaphragm 1 which heats rapidly and forms the seal. The blocks 2, 19 move upwardly whilst the element 3, 20 remains in contact with the seal which cools rapidly, after which cooling the element 3, 20 moves upwardly. The member 5 may consist of a silicone rubber strand. The frame 7 is supported on a plate 9 resiliently mounted by a rubber bearing on a base 10, the plate 9 acting to relieve the flange of the container 15 of the weight thereof during sealing. Irregularlyshaped surfaces may be sealed by using a suitably shaped diaphragm 1. A number of frames 7 may be disposed in carriers 8, Fig. 2, for paternoster-like rotation on an endless intermittently movable chain 24. A number of frames 7 may be disposed side-by-side and perpendicular to the feed direction on each carrier 8. |
