on the rear bed r alternate needles are pressed off at row 6 knitting of the weakened zone 41 commences with the repeat unit r3 which may be repeated as is desired for example for eight to ten courses thereafter at row 7 the normal single jersey repeat unit r2 is repeated as is required to finish the single jersey flap and rows 8 10 represent the recommencement of the knitting of the double jersey structure fabric on both needle beds f and r referring to fig6 there is shown a piece of fabric cover 13 having a portion of fabric 50a with two zones 51 of weakness or loose knitted structure formed therein the portion of fabric 50a is shown in fig7 gathered into a flap 50 extending in a wale wise direction w of the fabric so that the center line cl of the portion 50a forms the peak cl of the flap 50 the root of the flap 50 will be sewn along the line 57 as is illustrated in fig3 with reference to fig8 the three rows 1 3 illustrate the basic repeat unit r1 for the double jersey fabric as shown in fig5 knitted from the three yarns 42 44 as described previously after a.