The utility model discloses a be applied to plug feed shaft on mandrel -free filament winding machine, including the pipy axle main part of circle, the inside of plug subshaft main part is passed, the lateral wall middle part of axle main part is equipped with the inside open slot of an at least penetrating shaft main part. The utility model discloses cover the plug, the space of reducing the plug whipping reduces its amplitude, reduces cracked probability, even plug fracture also can not the departure and hurt the user, and owing to be equipped with the open slot in the axle main part, when the plug rotation was very fast, the plug probably stretched out in the open slot to the influence is operated, consequently still overlaps to be equipped with the protector on the plug, can prevent through this protector that the plug from stretching out, makes its security performance higher in the open slot.