Forming a removable closure member in situ

Claim 1

In the process of forming a removable closure member for the end opening in a bulbous, open-ended nipple or the like of resiliently flexible sheet material, the steps of interposing the nipple in the space between spaced mutually opposing surfaces of a pair of mold sections having mutually opposing recesses therein, one of which mold sections takes the form of an elongated mandrel which is inserted in the nipple and has a recess in the inserted end thereof, registering the end opening in the nipple with the recesses and while maintaining a seal about the opening between the inserted end of the mandrel and the surface of the other mold section, injecting a settable liquid molding composition into the cavity formed by the recesses and the opening in the nipple, to form the removable closure member, and relatively retracting the mandrel and the other mold section from the nipple and the closure member after the molding composition of the closure member has set in the cavity, said recesses having crosswise dimensions relatively parallel to the plane of the opening, which are adapted so that relatively enlarged inside and outside heads are formed on the closure member at the respective sides of the opening, the inside head formed in the recess of the mandrel, having a peripheral contour in directions extending relatively away from the opening, whereby the inside head is adapted to pass through the opening when a force is applied to the closure member in the direction of the outside head, relatively crosswise of the nipple and generally axially of the opening.