Deep-drawn aluminium screw closure for glass containers under pressure, and deep-drawing device for the manufacture of the top portion of such a closure

摘要

A deep-drawn screw cap of aluminum for glass bottles under internal pressure, where the transition area between the upper end face 1 to the lateral thread face 2 up to now was always evenly deep-drawn, now is to have at least one undeformed partial area 8. Because of this, sealing against the lateral edge 7 of the mouth is partially disrupted and a chance for the escape of gas is purposely provided in case the internal pressure in the glass bottle should rise too high. If required, a plurality of such partial areas 8 may be provided. In the deep-drawing device for a sealing head for the production of such screw caps the inner recess 12 should provide at least one partial enlargement 14 oriented towards the center axis 13 and extending approximately to the diameter of the preceding recess 11.