Plastic bottle cap

Claim 1

A tamper-indicating plastic bottle cap to be fitted to a bottle neck having a bead comprising: an inner stopper member made of a flexible plastic material, said inner stopper member having a skirt portion provided with an annular radially inwardly projecting portion at the inside of the skirt portion for engaging over the bead of the bottle neck, and an outer cap member made of a plastic material more rigid than that of the inner stopper member, said outer cap member being composed of an annular top portion and a skirt portion integrated with the annular top portion; either the skirt portion of the inner stopper member or the skirt portion of the outer cap member having uniformly spaced first and second annular recesses formed therein, and the other having at least one annular radially projecting portion to be received within said first and second annular recesses; said inner stopper member having an integrally formed downwardly extending inner cylinder, said inner cylinder being provided on its outer periphery with a plurality of spaced annular ribs; and said inner stopper member further having an annular ring-like projection on the lower surface of its top portion to be brought into sealing contact with the bead of the bottle neck; said skirt portion of the inner stopper member having notches or slits at least at the lower portion of the outer skirt, and being broader toward the lower terminal edge thereof so that broadened portion forms a stopping shoulder on which the lower end of the skirt portion of the outer cap member is caught therein so as to avoid the risk of the outer cap member being inadvertently brought into a seal position relative to the inner stopper member before stoppering the bottle; and, said outer cap member having a ring pull positioned within the annular top portion of the outer cap member, said ring pull being integrally formed with a portion of the annular top portion of the outer cap member and said portion of the annular top portion having slits or grooves forming score lines on both sides of said portion for easily breaking the outer cap member.