| 摘要 |
1,109,547. Moulding sliding clasp fastener elements. OPTI HOLDING A.G. 14 April, 1966 [23 April, 1965], No. 16367/66. Heading B5A. [Also in Division E2] A process for the manufacture of the top and bottom stop members 5, 6 of sliding clasp fasteners having fastener stringers with interlocking elements made from a plastics material comprises laying thermoplastic foil across one or both faces of the lengths of interlocked tapes from which the stringers are cut, then softening the interlocking elements and the foil by the application of high-frequency di-electric heating across an air gap sufficiently wide to effect virtually uniform heating of both the interlocking elements and the foil despite the greater thickness of the former, until both are soft enough to be welded and only then applying pressure to join the foil to the tapes with simultaneous shaping of the top and bottom stop members of the mutually welded foil and the material of the interlocking elements. The process is carried out by apparatus comprising a two-part die tool having die and punch parts, formed with recesses corresponding to the forms required for the stop members, one part at least of the die tool being movable towards and away from the other and the two parts of the die tool being connected to a high-frequency oscillator to act as electrodes, and control means for the relative movement between the tool parts to provide that when the high-frequency current is switched on the parts are held separated by a gap wide enough for substantially uniform heating of the material between them, and that after the high-frequency current has been switched on the movement can take place to bring the parts to a closed position with the die gap of predetermined amount to effect the welding and pressing operation. The movement of the die tool to the closed position can take place at a constant speed but it is preferred to advance the die to its closed position in a series of fixed pressing positions so that the shaping of the foil and interlocking elements takes place progressively. At the same time as the top and bottom stopmembers 5, 6 are formed to shape, cutters in the die remove material to separate the stop members. Each heating and pressing operation forms the top stop members of one fastener and the bottom stop members of the adjacent fastener and these are subsequently separated by a transverse cut through the tapes. |
