left out at certain sections the maximum dimension of the latchguard cams in a circumferential direction may thus be reduced to less than 1 5 of the entire circumferential extension of the cam box preferably to about 1 7 of said extension whilst the lower portions 22a 23a may be rectilinear throughout as shown in fig2 the reduced size of the latchguard cams 22 23 and the simplified shape thereof afford an economy of material and labor in addition to reducing the stresses in the open latches of the needles knitting in the upper cylinder moreover the stresses in the latches of the needles knitting in the lower cylinder are removed during the return stroke of the reciprocating movement when forming the heel of a stocking or sock article since where such stresses were present in the prior art machines the latchguard cams 22 23 have been eliminated from the machine according to this invention as is apparent from a comparison of fig1 and 2 the movable cams 8a 9 and 11 have been removed from the inventive machine which also affords the elimination of their respective actuating linkages thus simplifying the machine construction and reducing the cost thereof it is also possible to eliminate the movable slider pushing cams 12 13 and 14 and arrange a fixed ring.