| 摘要 |
989,369. Seaming non-metallic sheet material. DU PONT OF CANADA Ltd. June 28, 1962 [April 13, 1962], No. 24803/62. Addition to 955,618. Heading B5K. Apparatus for sealing thermoplastic materials comprises means 22, 24 for applying heat and pressure to effect a seal in thermoplastic material 1 conveyed through the apparatus and at least one pair of rotatable bands 23 arranged such that the distance between the bands 23 measured in the plane parallel to the material is greater at the feed end than at the discharge end of the apparatus and arranged to frictionally engage the material 1 to move the material adjacent the seal towards the molten pool of the seal to reinforce the material at the seal. The bands 23 pass around driven pulleys 21 and idler pulleys 20. Sealing bands 24 are electrically heated from brushes 26. Flexible covered pressure rollers 32 press the bands 23, 24 against the material 1 and transmit the drive from the bands 23 to the bands 24. Tension rolls 25 are provided. A thin coating of silicon oil may be applied to the surfaces of the bands 24 to prevent adhesion thereof to the seal. |
