| 摘要 |
This annular inflatable element comprises two ring-shaped elements interconnected by an inner closed belt and an outer closed belt. All these elements are welded together, and all the welds are of the sleeve coupling type without requiring any complementary or additional welding operation. The last sleeve-coupling weld is formed by placing the outer belt against the inner surface of the annular electrode, and the belt lips are folded firstly outwardly and then inwardly between the electrode and registering contra-electrodes. Paper welding barrier are interposed between the first and second folded portions of the belt lips, and the lips of the ring-shaped elements are placed against the contra-electrodes, respectively, so that the last two sleeve-coupling welds can be accomplished simultaneously. This invention is applicable notably to the manufacture of rubber dinghies. |
