The injection moulding plant (1) used for the plastic covering tube has an injection head (2) comprising a central coil-shaped unit (4) fitted in a channel (3). This unit is centered in the channel by vanes or spokes (5). Molten plastic (6) is fed to the head, and is past the vanes. At the head outlet a tubular jet (9) of plastic is produced and then cooled (10), from the outlet (11) of which the ...

Telephone jacks (A,B,C) are used to connect telephone units to the modems, with a device (D) reducing to an acceptable level transients on charge metering impulses from telephone stations of the older type. Two two-way change-over switches (E,F) change between telephone and data transmission and reception positions, with telephone plugs (G,H) connecting the telephone subscribers to be considered f...

The cutting blades (10,11) execute a movement to and from the plank (3) so that intermittent processing occurs.