Patent ID: 9701447
Date: 2017-07-11
CPC Classifications: B21D,B65D

Claim:
1. A method of converting a conventional lid by adding a vacuum release button to a thin sheet metal lid having a vertical axis and a horizontal peripheral rim portion with a sealant material bonded to the lid and adapted to be releasably secured to the open end portion of a container having a vacuum enclosed food product, the method comprising the steps of pressing a center portion of the lid upwardly to form a rounded dome-shape portion having a sheet metal thickness less than the sheet metal thickness of a lid portion extending around the dome-shape portion, pressing the dome-shape portion downwardly to form an annular cavity surrounding an upwardly projecting vent button, forming the vent button with a non-horizontal sloping top wall extending upwardly to a top edge portion of the top wall with the top edge portion connected to a substantially vertical arcuate wall, forming a curved reinforcing bead within the lid portion forming the cavity at a lower end of the sloping top wall and in opposing relation to the substantially vertical arcuate wall, pressing an arcuate score line into the sheet metal lid portion forming the cavity and adjacent a bottom portion of the substantially vertical arcuate wall, bonding a sealant material to an inner surface of the button below the score line with the sealant material being effective to define a vacuum release gap in response to depressing the top edge portion of the button above the score line to shear the score line for releasing vacuum from the container.