| 摘要 |
<p>900,914. Extruding netted fabrics. PLASTIC TEXTILE ACCESSORIES Ltd. Feb. 24, 1961 [March 9, 1960], No. 8256/60. Class 87(2). In a method of manufacturing integral plastic netting, comprising the continuous extrusion of plastic materials to form a net, tension applied to the net is increased during the periods of extrusion of the mass strands to form necks in the strands prior to their solidification. Apparatus for manufacturing said netting 1 includes a screw extruder 4 which feeds plastic material to the annular space 5 between die members 6 and 7 which are rotated in opposite directions by drive chains 8 and 9 from the gear box 12 driven by a motor 13 and which die members are provided with an equal number of strand forming grooves so that integral net intersections are formed when the grooves are in registration. The extruded net is hauled over a former 19 and through a setting bath 16 by and between rollers 17 and 18 driven by a motor 27 via a chain 28 and a shaft 29. A reciprocating crank 31 is journalled on the shaft 29 and is coupled to said shaft by a clutch 30 when said crank and shaft have the same rotational direction. The crank 31 is coupled with a connecting rod 32 adjustably connected to a rotary crank 33 driven through agear chain 34-39 by the motor 13. The management and timing are such that cyclic increments of rotational acceleration are imparted by the crank 31 to the rollers 17 and 18 to give an increased tension in the net to produce necking of the unset strands in the zone 21. Alternatively, the apparatus for varying the net tension may be such that (a) the distance between the extrusion point and the haul off rollers 17 and 18 is variable or, (b) the length of the path along which the net travels between the extrusion point and the haul off rollers is variable or (c) supplementary haul off rollers are included, between the extrusion point and the rollers 17 and 18, to operate during the periods of formation of the strands. Specification 836,555 is referred to.</p> |
