RESEALABLE PRESSURE RELEASE CLOSURE

摘要

This specification discloses certain improvements in resealable pressure releasing closures of the type disclosed in U.S. Pat. Nos. 4,105,134 and 4,155,480 Debenham et al. In the several improvements disclosed in the specification, the resealing properties of the closure are improved by reducing the concentration of the flexure of the closure at the connection between the closure and the can end to thereby reduce the extent to which the material defining the connection permanently deforms during the opening operation. In one embodiment the pressure releasing closure or tab 20 has a connection 23 to the can end which is at substantially the same level as the adjacent portion of the closure by the provision of an area 26 immediately behind the connection which is downwardly depressed so as to be co-planar with the tab 20. In another embodiment the upwardly raised bead 31 extends from the connection 32 into the closure 30 to substantially stiffen the connection 32 and discourage bending of the sheet metal at the connection 32. Other embodiments involve the cold reduction of the pressure releasing closure and the shape of the closure to make the bending thereof more uniform during the opening operation.