Abstract: A method and apparatus for closing and sealing the end of a container having a tubular body wherein the container and closure portion includes front, rear and side panels each extending axially from the tubular body in the open position of the end closure. Each of the end closure panels may have a sealing strip defined at its outer end by a scored line with the rear panel including a closure flap-extending from the outer edge of its sealing strip. The end closure panels are folded to a flat closed position by closing jaws with the sealing strips and closure flap projecting axially from the tubular body, after which the sealing strips are sonically welded together. The closure flap and sealing strips are then folded flat, and the closure flap is welded to the outer surface of the front end closure panel.

Abstract: Apparatus and method for forming sealed joints by welding layers of thermoplastic coated paperboard together. One outer surface of the paperboard layers is placed in engagement with back-up means, and the opposite outer surface of the paperboard layers is engaged by vibrating means so that the thermoplastic coating of the paperboard is heated by the vibration to weld the layers together. The apparatus and method is particularly useful in forming sealed joints for paperboard cartons, such as milk cartons of the type shown, for example, in U.S. Pat. No. 3,309,841. The vibrating means may be an ultrasonic transducer of the type disclosed in U.S. Pat. No. 3,526,792, for example.

Abstract: Carton sealing apparatus for sealing a rectangular end closure of a thermoplastic coated paperboard carton by ultrasonic vibrations. The apparatus includes an anvil, or backup member, and an ultrasonic vibrating tool. The mandrel is received in the carton with the end closure to be sealed folded against the smooth end surface thereof. The ultrasonic vibrating tool engages the end closure on the opposite side thereof from the mandrel, and, when energized, generates heat sufficient to cause the thermoplastic coating of the paperboard to flow and weld the layers of the end closure together. Ribs project from the end surface of the vibrating tool to provide a sealing pattern of "bow-tie" configuration, the ribs having various heights with respect to the end surface of the vibrating tool to accommodate changes in the number of layers of paperboard at the different areas on the end closure.