Ex-cell-o Gmbh

Earl W Walke, Jr

Robert E Lisiecki

Duncan J Crawford

Eric A Braun

Eugene R Bosche

Harry B Egleston

A method and apparatus for forming a seal between layers of thermoplastic coated paperboard or the like wherein there are different numbers of layers and varying thicknesses at different locations within the area to be sealed. The apparatus includes an anvil having a work surface for engaging one outer surface of the layers and a horn that vibrates at a predetermined frequency when energized. The horn has a work surface that opposes the work surface of said anvil. A control circuit is operable for sequentially; (1) pre-triggering said horn, to energize it and cause it to vibrate; (2) moving said anvil and energized horn into the sealing position to clamp the paperboard layers therebetween and maintaining the clamping pressure over the entire area of the layers within predetermined limits, (3) holding the energized horn in the sealing position with respect to the anvil for a predetermined period of time to cause the thermoplastic coating of the paperboard layers between the work surfaces to be activated to flow, (4) deenergizing the horn to terminate the vibration thereof, (5) holding the anvil and deenergized horn in the sealing position with the paperboard layers clamped between the work surfaces thereof for a predetermined period of time to permit the activated thermoplastic coating to set, and (6) retracting the horn and anvil with respect to each other to unclamp the sealed paperboard layers.

Apparatus and method for vibration sealing

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.

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Oak Park, MI, United States of America

Earl W Walke, Jr