| 摘要 |
844,199. Extruding coatings on cores. STANDARD TELEPHONES & CABLES Ltd. Feb. 28, 1958 [March 7, 1957], No. 6532/58. Class 87(2). An extrusion-core coating apparatus comprises a block member 2 having an axial channel 4, a tapered member 14 disposed in the channel 4 and having a helical rib the edges of which are of differing pitch so that the width of the helical groove diminishes towards the smaller end of the member 14, a die 5 having a tapered bore 6 within which the small end of the tapered member 14 is centred, a chamber 3 through which the plastic material is fed and a second channel 3<SP>1</SP> extending from the chamber 3 to the channel 4 in a direction tangential to the base of the helical groove in the member 14 and being of rectangular cross-section and of a size equal to that of the groove at that position. The tapered member 14 has a tip 11 with a ball and socket seating 15 so that the tip 11 may be centered in the die 5 by means of screws 26 in a collar 20 and its helical rib may be formed with steps 14<SP>1</SP> so that its depth decreases towards its tapered end. The tip 11 has a bore 30 for the passage of the core to be coated and has suction holes 31 leading to a line 33 enabling the plastic sheaf to be drawn on to the core. A cover 27 with an inspection window 28 is provided and heating is by electrical elements 9, 19.
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