Extrusion head for producing polymeric material fibres

Claim 1

An extrusion head for the formation of polymeric material fibers comprising: an elongate body member having a generally wedge-shaped cross section including two substantially planar sloping faces convergent to and terminating at a line of intersection, a plurality of capillary-like channels of substantially the same cross-sectional size and circular cross section located in said body member and each extending from an individual orifice formed at said line of intersection spaced apart from the individual orifice of the other channels internally of said body member substantially parallel to and separated from others of said channels and substantially perpendicular to said line of intersection, whereby the axis of each of said channels and said line of intersection lie in a first plane, first supply means in fluid flow communication with the ends of said plurality of channels remote from said line of intersection for feeding molten polymeric material through said plurality of channels towards said orifices, a first elongate block member having a face of complementary shape to that of one of said two planar sloping faces and secured in engagement with said one of said two planar sloping faces, a second elongate block member having a face of complementary shape to that of the other of said two planar sloping faces and secured in engagement with said other of said two planar sloping faces, said complementary-shaped faces each having one longitudinal edge located substantially common with said line of intersection, whereby said block members engage each other at said line of intersection, a plurality of grooves formed in each of said complementarily-shaped faces of equal number to each other and to the number of said plurality of capillary-like channels, each of said grooves defining a passage with the adjacent planar sloping face of said body member, said grooves in each said complementarily-shaped face being parallel to each other and having substantially the same cross-sectional shape, respective grooves in each said complementarily-shaped face and one of said channels being arranged to lie in a second plane situated substantially perpendicularly to said line of intersection and to said first plane, respective grooves terminating at said line of intersection in an opening, and second supply means in fluid flow communication with each of said plurality of passages remote from said line of intersection for feeding air under pressure to said plurality of passages towards said line of intersection, each of said orifices having a circular cross section when viewed along the intersection of said first and second planes and having a part-elliptical cross section when viewed along said second plane towards said first plane.