Package box for a spark plug

Abstract

In a package box for a plurality of spark plugs, a paper tray has an array of lower cellular boxes provided to accommodate lower portions of spark plugs to protect their spark gaps against dimensional alteration, and an array of upper cellular boxes provided to retain upper portions of the spark plugs in place. A casing package is provided to accommodate the paper tray. The lower cellular boxes have circular crease lines each about the size so that Individual thread portions of the spark plugs are to be inserted, and having a plurality of incision lines provided to be oriented radially toward central portions of the circular crease lines. Accommodation holes are formed with pluralistic tabs by expanding the incision lines and bending along the circular crease lines so as to accommodate the thread portions of metallic shells of the spark plugs with the thread portions supportably engaged by the tabs when forcing outer electrodes and the thread portions of the spark plugs against sections surrounded by the circular crease lines. The upper cellular boxes have upper open ended U-shaped retainer holes to admit the head portions of insulators of the spark plugs so that the tray accommodates the spark plugs with the insulators exposed between the array of the upper and lower cellular boxes.