Bottle cap

Abstract

A bottle cap, having a top portion and a skirt portion which surrounds the top portion and extends downwardly from a circumference of the top portion; an inner wall of the skirt portion is provided with screw threads; a lower periphery of the skirt portion has openings. The screw threads are positioned near to the lower periphery of the skirt portion, and the openings partially interrupt the screw threads.

What is claimed is: 
     
         1 . A bottle cap, comprising a top portion and a skirt portion; the skirt portion surrounds the top portion and extends downwardly from a circumference of the top portion; an inner wall of the skirt portion is partially provided with screw threads; wherein a lower periphery of the skirt portion comprises openings. 
     
     
         2 . The bottle cap of  claim 1 , wherein the bottle cap has a circular structure. 
     
     
         3 . The bottle cap of  claim 1 , wherein the openings are in rectangular shapes, semi-circular shapes or triangular shapes. 
     
     
         4 . The bottle cap of  claim 1 , wherein there are two said openings symmetrically arranged with respect to each other. 
     
     
         5 . The bottle cap of  claim 1 , wherein there are four said openings evenly spaced with respect to one another along a circumferential direction of the skirt portion. 
     
     
         6 . The bottle cap of  claim 1 , wherein the screw threads are positioned near to the top portion. 
     
     
         7 . The bottle cap of  claim 1 , wherein the screw threads are positioned near to the lower periphery of the skirt portion; the openings partially interrupt the screw threads. 
     
     
         8 . The bottle cap of  claim 1 , wherein each of the openings has a height which is one seventh to half of a height of the skirt portion, and a width which is one twentieth to one third of a circumference of the skirt portion.