| 摘要 |
A plunger for forming thermoplastic material disposed in a closure shell into a closure insert with a cushion pad or bead by sealing the material between the crown and working surface of the plunger and flexing a portion of the working surface to form the material into the desired shape. The plunger includes a punch, elastomeric material and a sealing means. In one embodiment, the plunger comprises a reciprocal punch having a lower end surrounded by cylindrically-shaped elastomeric material, and sealing means that is disposed about the outer wall of the elastomeric material and has a lower ledge contacting the bottom surface of the elastomeric material. A spring means maintains the elastomeric material in sealing engagement with the punch and sealing means, and maintains the punch, elastomeric material, and sealing means in mechanical engagement. The outer diameter of the lower portion of the plunger is less than the inner diameter of the sealing means to provide a gap therebetween, which facilitates in the alignment of the closure shell beneath the plunger, and enables the sealing means to move relative to the plunger to accommodate any skewness between the plunger and the closure shell.
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