Abstract: This invention relates to electric fuses having tubular casings having a high bursting strength and to the method and materials by which these casings are made. Such tubular material has also other applications than casings for electric fuses. Tubular structures made in accordance with U.S. Pat. No. 3,979,709 of which this is a division thereof have a plurality of plies which may include strips of non-woven, non-uniformly oriented glass fiber mat, composite strips of woven glass fiber cloth and non-woven glass fiber mat and glass fiber rovings. The plurality of strips are self overlapping and their overlaps are angularly displaced relative to one another. The tubular structure further includes a synthetic thermosetting resin integrating the plurality of strips into a multi-ply laminate.This invention relates to a process of manufacturing tubular structures of the above referred-to kind by pultrusion.

Abstract: An electric fuse having a pultruded casing of polyester resin including an outermost ply of woven glass cloth and an innermost ply of woven glass cloth and at least one intermediate ply of non-woven glass fiber mat. The casing of the fuse supports at the ends thereof a pair of ferrules which are press-fitted. The axially inner ends of said ferrules form narrowly knurled cones, and the knurled area encompasses the entire periphery of the axially inner ends of said ferrules rather than spaced points thereof.

Abstract: An electric fuse having a casing which has a substantially prismatic outer surface rounded at the longitudinal edges thereof. The casing is a multiply glass cloth laminate including thermosetting resin and is formed by pultrusion.