| 摘要 |
This invention relates to a method and a device for the formation of a hole in a plastic pipe. Corrugated pipes provided with holes are widely used as drainage pipes. According to a known method, a corrugated pipe is first manufactured and thereafter provided with holes by means of mechanical cutting devices. This manufacturing method requires two working steps, and the cutting device must be adjusted whenever the size of the pipe is changed. A pipe (11) can be provided with holes already during the manufacture thereof by providing a mandrel (8) and chill moulds (1) surrounding the mandrel and moving in the longitudinal direction thereof with openings (15, 16) which are intermittently in alignment so that when pressure air is fed into the opening (15), it is discharged through the wall (11) of the pipe into the opening (16) opposite thereto. |
