14 is forced to simply shift to one side of the needle cylinder 2 as if it were rigid with the rotating structure 10 this avoids any engagement of the tooth 31 39 with the butt 5 39 as is apparent from a comparison of fig7 and 9 it should be noted here that the tip of the hook 25 is still engaging the periphery of the disk 14 between two consecutive teeth 30 during the rotation of the disk 14 but this has no influence on the lever 24 until the surface 32 meets the leading flank of the tooth 30 as shown in fig9 where the disc 13 retaining step is on the point of being completed at this stage in fact the lever 24 is urged to gradually rotate clockwise thus gradually reducing the contact area between the surface 33 and tooth 31 of the now stationary disk 13 until the tooth 31 and the entire disk 13 are fully released as soon as the hook 25 reaches the topmost portion of the tooth 30 as shown in fig1 the disk 13 tripped forward by the spring 19 action is again brought to its normal entraining position but without the tooth.