Bottle with adjustable bottom

Abstract

A bottle whose bottom can be adjusted to eject air is disclosed. The bottle includes a body, a ball bung and a bottom assembly. The body is of a cylindrical shape and has a mouth and a bottom end. The bottom end is open and provided with an inner thread. The ball bung is used for sealing the mouth. The bottom assembly includes a base, a post and a piston. The post is axially connected on the base. An outer thread is formed on a cylindroid thereof for screwing with the inner thread. The piston is axially connected atop the cylinder and fits snugly into the body to form a gastight status.

What is claimed is: 
     
         1 . A bottle comprising:
 a body, being of a cylindrical shape, having a mouth and a bottom end, wherein the bottom end is open and provided with an inner thread;   a ball bung, received in the body for sealing the mouth; and   a bottom assembly comprising:
 a base, being a disk; 
 a post, axially connected on the base, an outer thread being formed on a cylindroid thereof for screwing with the inner thread; and 
 a piston, axially connected atop the cylinder, fitting snugly into the body to form a gastight status. 
   
     
     
         2 . The bottle of  claim 1 , wherein the bottom end of the body is provided with a ring, and the inner thread is formed on an inner edge of the ring. 
     
     
         3 . The bottle of  claim 2 , wherein the ring has an outer wall, an inner wall and an annular gap therebetween, a width of the gap is slightly less than a thickness of wall of the body so that the gap can be inserted by the bottom end and the ring can tightly nips the body on the bottom end, and the inner thread is formed on the inner wall. 
     
     
         4 . The bottle of  claim 1 , wherein a diameter of the base is substantially equal to an outer diameter of the bottom end of the body. 
     
     
         5 . The bottle of  claim 1 , wherein a periphery of the piston is provided with at least one O-ring. 
     
     
         6 . The bottle of  claim 1 , wherein a diameter of the ball bung is greater than an inner diameter of the mouth. 
     
     
         7 . The bottle of  claim 1 , wherein the ball bung is made of a soft material.