| 摘要 |
<p>After the injection moulding in rigid synthetic material of the actual socket end fitting for receiving the smooth spigot end of a pipe section with which it is to make a joint, the sealing ring is moulded pref. in the same tool directly into the socket end, in elastically deformable material. During the moulding of the socket end, radial passages through its wall are kept open and the material for the sealing ring is injected through these passages. Method remedies the shortcomings of existing methods of providing a sealing ring in the socket end for socket and spigot type fittings for joining pipes. The injection moulding tools used are simple and uncomplicated. There is no need for time consuming machining for the insertion of the sealing ring after the socket has been moulded and there is no possibility that the sealing ring can be omitted either accidentally or by intention. Immediately on ejection from the mould the fitting is ready for use, whilst the sealing ring cannot be displaced.</p> |
