| 摘要 |
A method of sealing a tube of flexible thermoplastics material by welding in which opposite sides of the tube are pressed flat between two jaws. The flattened tube thus has two opposed flat walls which have inner faces in contact, and these flat walls are connected at two opposite edges by folds caused by the flattening of the tube. The jaws are maintained a fixed distance apart, and one is rapidly reciprocated along its longitudinal direction by a vibrator, relatively to the other jaw. This causes the contacting flat walls to rub and become so heated by friction that the contacting plastics faces melt. These molten areas unite in a weld when reciprocation of the jaw is stopped and the plastics cools. |
