This invention relates generally to valves for molded inflatable articles, particularly to valves which accept an inflating needle, and to the method of forming the valve during the molding process.
There are several types of valves known for inflating articles such as balls, toys, tubes and similar articles. One type, represented by U.S. Pat. Nos. 3,107,683 and 4,341,382 utilizes metal valve parts inserted after the inflated article is formed. Another type, represented by U.S. Pat. Nos. 3,100,641, 3,204,959 and 3,220,729, utilizes metal or plastic parts which are placed in the mold prior to forming the inflated article. This valve is in the form of a tube or sleeve including a side aperture which pushes out or displaces the stem when pumping begins. Another type, more pertinent to this invention, is represented by U.S. Pat. Nos. 2,295,804, 2,302,985, 2,318,115, 2,387,455, 2,600,862, 2,760,775, 2,934,344, 3,174,501 and 4,660,831. These patents relate to inflatable articles in which the valves are self-sealing after withdrawal of an inflating needle. The valve chamber either contains a soft, sticky, puncture-sealing composition or a plug with a passage in the form of a slit which is effectively sealed by air pressure on the outside of the walls of the chamber which holds it. Inflation, thus, closes the plug opening. In each instance the plug is forced into the chamber by compressing it, so that it can be held in the chamber by some overlapping element such as a shoulder, a rib, a flange or a groove. The disadvantage of such an arrangement is that the pressure required to insert the plug, equals the pressure bringing about its removal. The use of a bonding agent for the plug is not totally satisfactory because it limits valve replacement.
The invention herein overcomes these disadvantages in a manner not disclosed in the known prior art.