Abstract: A snap on bottle cap for a container having a neck configuration including an annular shoulder over which the bottle cap is engaged so as to be self-retaining thereon. The bottle cap is formed of resilient material permitting distortion of the cap when it is applied to the bottle. A ring is positioned around and fastened to an annular flange of the cap by a plurality of frangible elements and it is attached to a portion thereof separated from the remainder by spaced cutaway areas. The ring thus may be used as a pull ring to free the portion of the annular flange as necessary in removing the cap by permitting the remainder of the cap to expand circumferentially so as to become disengaged from the annular shoulder on the neck portion of the bottle. The separation of the ring provides a visual indication of tampering.

Abstract: Devices for making hollow articles such as bottles from thermoplastic resin with a blow mold wherein a parison in the mold is shaped by air blown through a blow pin carrying a mandrel arranged to seal a portion of the parison with respect to a section of the mold in order to provide an additional quantity of thermoplastic resin in a critical area to be subsequently shaped in a smooth inner annular surface by the mandrel.