Mule pattern slippers made by cutting and welding foamed plastic sheet - with projected overlaps to inhibit lateral curling

摘要

Mule pattern slippers are made from two layers of thermoplastic sheets so that one layer provides the upper for the front half of the slipper and a lining to cover part of all of the exposed hell of the sole, and the other layer forms a sole to which the upper and heel lining are bonded by a peripheral intermittent weld. The slippers are made by leading one layer as a strip past cutters which apply one or two cuts to limit the free edges of the upper the heel liner, thus superimposing the precut layer on a second layer to pass cutters which weld the layers together in a slipper profile. The sheets require little manipulation or treatment, permitting high production rates. The patterns of the ends of the upper and the heel cover stiffen the structure laterally to inhibit curling when not in use. The layers are each composite sheets of a thermoplastic flexible polyurethane foam about 7 mm thick covered on the faces to be in contact with the foot with a non-cellular layer of e.g. nylon fabric.