Tube-forming apparatus
AssigneeThomas J. Lipton Co., Divison of Conopco, Inc.
InventorsGeoffrey W. Vernon, James Goodwin
Life of this patent
Estimating the term…
Abstract
A flexible heat-sealable web is shaped continuously into a tubular cross-sectional shape, e.g. as an intermediate stage in the production of infusion bags comprising severed and sealed lengths of the tubular shape. The web is drawn along a shaped shoe and side margins of the web are folded over opposite sides of the shoe by rollers and fingers to place the opposite side edges of the web in overlapping relationship against the shoe. The overlapped edges pass between a roller mounted in the shoe and an external heated roller to be pressed between the two rollers in order to lap weld the edges together as the web travels along the shoe. The shoe continues to form the web downstream of the welding station into a flattened tube.
Claims13
Apparatus for shaping a flexible heat-sealable web into a tubular cross-section shape, said apparatus comprising a former member for disposition within the width of the web, means for progressing the web along the former member, means for folding opposite side margins of the web over the former member and for placing edges of said side margins in overlapping relationship against the former member, a mobile element mounted on said former member providing a support surface for said overlapped side edges which is movable in step with the web, and means for heating and pressing said edges to lap weld said edges together as the web travels along the former member said former member having a transverse profile that is hollow from below to provide a space below the former member for the passage of material placed on the web in its central portion between said folded-over side margins.
Apparatus for shaping a flexible heat-sealable web into a tubular cross-section shape, said apparatus comprising a former member for disposition within the width of the web, means for progressing the web along the former member, means for folding opposite side margins of the web over the former member and for placing edges of said side margins in overlapping relationship against the former member, a mobile element mounted on said former member providing a support surface for said overlapped side edges which is movable in step with the web, and means for heating and pressing said edges to lap weld said edges together as the web travels along the former member, said former member comprising a reducing height and increasing width cross-sectional profile downstream of the region of the member in which said lap weld is formed for progressively flattening and widening the tubular shape of the web after the welding of the web edges.
Apparatus for shaping a flexible heat-sealable web into a tubular cross-section shape, said apparatus comprising a former member for disposition within the width of the web, means for progressing the web along the former member, means for folding opposite side margins of the web over the former member and for placing edges of said side margins in overlapping relationship against the former member providing a support surface for said overlapped side edges which is movable in step with the web, and means for heating and pressing said edges to lap weld said edges together as the web travels along the former member, said former member comprising lowermost surfaces against which the central portion of the web between said folded-over side margins is applied and said surfaces of the former member are convexly curved along the direction of progress of the web.
Dependencies are inferred from the claim text.