Abstract: A one-piece reusable closure for home canning. The closure is adapted for sealing home canning containers, such as "Mason Jars." The closure has a one-piece threaded cap with a bonded annular closed-cell foam gasket at the periphery of the central cover section positioned to seal against the jar lip. A central cover portion is dished outwardly and moves to an inwardly dished configuration when a partial vacuum is developed in the container. When the closure is unscrewed, the central cover section springs with an audible click to the outwardly dished configuration. The closure incorporates a stop mechanism to limit the extent of gasket compression by limiting the threaded engagement of the closure with the container. The mechanism can comprise either a deformed thread groove or a lower edge of the closure adapted to abut a flange on the container when the desired gasket compression is achieved. The compression of the gasket material against the lip of the container is thus limited to a predetermined degree.

Abstract: A one-piece reusable closure for home canning. The closure is adapted for sealing home canning containers, such as "Mason Jars." The closure has a one-piece threaded cap with a bonded annular closed-cell foam gasket at the periphery of a central cover section positioned to seal against the jar lip. The central cover portion is dished outwardly and moves to an inwardly dished configuration when a partial vacuum is developed in the container. When the closure is unscrewed, the central cover section springs with an audible click to the outwardly dished configuration. The closure incorporates a one-way pressure relief mechanism to limit the pressure in the container. The mechanism comprises a resilient sealing member overlying an orifice in the central cover section of the lid. As the container contents are heated, gas pressure in the container will increase and force the resilient sealing member from the orifice. Gases will then be vented through the orifice under the resilient sealing member.

Abstract: A one-piece reusable closure for home canning. The closure is adapted for sealing home canning containers, such as "Mason Jars." The closure has a one-piece threaded cap with a bonded annular closed-cell foam gasket at the periphery of the central cover panel positioned to seal against the jar lip. A central cover portion is dished outwardly and moves to an inwardly dished configuration when vacuum is developed in the container. When the closure is unscrewed, the central panel portion springs with an audible click to the outwardly dished configuration. Limiting projections extending downwardly into the gasket bear and compress the gasket material against the lip of the jar to control tightening of the closure on the jar so that, when the jar contents are heated, gases will be vented under the circumferentially spaced portions of the gasket.