| 摘要 |
857,031. Seaming non-metallic sheet materials. ROSE BROS. (GAINSBOROUGH) Ltd. May 15, 1959 [May 29, 1958], No. 17099/58. Class 42 (1). [Also in Group XVII] A seam is formed in a bagmaking apparatus comprising a collapsible former 11 having a longitudinal groove 14 over which the overlapping seam is placed for forming by a heated sealing bar 17 having a curved operative tip 16 which enters the groove. The seam is thus formed with the minimum of contact and heat transfer between the bar 17 and the former 11. Similar grooves 27, 28 are preferably provided in the end of the former 11 to co-operate with an end sealing bar having similar curved operative tips. |
