Ultrasonic paper welding
OwnerBernard T. Sendor, Mortimer S. Sendorinventors
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Abstract
This invention provides a method and aparatus for welding together paper sheets, more especially for, but not limited to, bookbinding. The sheets are held in a desired relation with one another, and the portions to be connected are held together while subject to ultrasonic vibration which fuses ingredients of the paper so as to weld the fused areas together. A folded sheet can be welded across a midportion thereof and then folded along the weld or parallel to the weld to make a signature for a book; or stacked sheets can be bound together along their rearward edge portions by the ultrasonic vibrations.
Claims17
The method of bookbinding which comprises bringing together stacked sheets of paper comprising pages to be bound together as a book, said paper containing an ingredient that fuses at a temperature less than the charring temperature of cellulose in the paper, locating the sheets of paper in a stack with the pages in a desired order with respect to one another, holding the sheets with the pages in such order and while so held pressing the sheets together along the edge regions at which the rearward portions of the pages are to be bound together, exerting a localized pressure at said edge regions on one side of the stack of assembled sheets by a horn, and on the opposite side of the assembled sheets from the horn exerting pressure by an anvil, subjecting the horn to ultrasonic vibration to produce high frequency pressure impulses that heat the paper and weld together areas of contact of the paper between the horn and anvil, terminating the ultrasonic impulses before the paper is heated to a charring temperature and binding successive stacks along corresponding edge regions with the pages beyond said edge regions unconnected to one another.
The method of welding sheets together which comprises bringing together sheets containing material that fuses at a temperature less than the charring temperature of the sheets, locating the sheets in a desired relation to one another, holding the sheets in such relation while supported by a stationary anvil, pressing the sheets together and holding them against the stationary anvil by means of a vibrating horn, subjecting the horn to ultrasonic vibration to produce high frequency pressure impulses that heat the sheets between the horn and anvil, moving the sheets progressively across a space between the horn and anvil to weld the sheets together along their direction of movement with respect to the horn and anvil, characterized by adjusting the spacing of the horn and anvil with respect to the thickness of the sheets so that the sheets are firmly clamped and the vibration of the horn produces the progressive movement across the space between the horn and anvil.
Apparatus for binding books including in combination a conveyor for advancing a stack of assembled sheets to a welding station, ultrasonic welding apparatus comprising a horn for contact with the paper at the region to be welded, means for imparting ultrasonic vibration to the horn, means for perforating the assembled paper sheets along a region to be folded, a back-up anvil on the opposite side of the stack of paper from the horn and with surfaces on both sides of the region of perforating, and means for moving the anvil toward and from the horn to obtain a predetermined gap between the anvil and the horn through which the paper passes to be welded together.
Dependencies are inferred from the claim text.