Abstract: A tubular casing for use with food products which includes knitted stockinette, longitudinal threads and circumferential spiral threads that are held to stockinette by stitches located along the length of the casing. Each thread comprises an elastic thread formed from an inextensible yarn spirally wrapped around the outside of a rubber thread. As thread is stretched, the rubber thread extends and the helix angle of the spirally wrapped yarn reduces to the point where the yarn approximates a straight line. The inextensible yarn resists further stretching beyond this point. This point is the elastic limit for thread and it can be adjusted by varying the helix angle during manufacture of the elastic thread. Threads therefore allow the casing to be filed to a predetermined maximum diameter and result in the filled casing having a constant diameter throughout its length.

Abstract: The present invention provides an improved system of stitching for forming a casing of tubular netting, in which the casing comprises circumferential elastic members formed from at least one continuous spiral or a plurality of separate circular loops, and longitudinal members formed from a plurality of chain stitches interconnecting adjacent loops of the spiral or separate loops of the circumferential elastic members, resulting in a net-like appearance, the longitudinal chain stitches being attached to the circumferential elastic members such that, at each connection point of the chain stitching to an elastic member, a first chain stitch is attached to the elastic member and a further pair of chain stitches is attached to the elastic member and spaced either side of the first chain stitch such that, when the first and further pair of chain stitches are stretched, the first chain stitch is caused to pull on the section of the elastic member located between the further pair of chain stitches such that elastic d