Shirred tubular casing and apparatus including shirring member for its manufacture

Claim 1

A shirred tubular casing, comprising: a main fold structure comprising a series of windings, each winding including: two helically extending, outwardly pointing main folds in proximate relation to one another and having a height H measured as one-half of the difference between the outside and inside diameters of the casing, a first interspace between said two main folds defining first fold pockets therebetween, said first fold pockets having a depth less than the height H, a second interspace between successive windings of said main fold structure, having a width equal to or greater than said first interspace and defining second fold pockets therebetween, said second fold pockets having a depth substantially equal to H and forming the inner circumference of the casing, and a plurality of outwardly pointing primary accessory folds in said first interspace, said primary accessory folds connecting with said main folds and interconnecting to at least some extent with one another; and a plurality of secondary accessory folds in said second interspace forming an irregular zigzag line, wherein the surfaces of the shirred casing extending from said outwardly pointing main folds and from said accessory folds in the direction of the inner circumference extend at substantially right angles to the longitudinal axis of the shirred casing.