This invention relates to heat sealing tools in general and more particularly to a heat sealing tool which provides a greater degree of maintainability and flexibility than tools previously available.
Various types of heat sealing tools have been developed. An example of such is that disclosed in U.S. Pat. No. 3,523,176 which discloses an electric iron for heat sensitive adhesive tape for seaming carpets. As is conventional in devices of this type, it includes a handle, a heat control, a sole plate or heating shoe and a heating element disposed within the sole. The heating element in this particular device comprises an electric resistance heating element disposed within the sole plate. As shown in FIG. 7 thereof, the element follows a U-shape within the sole plate and terminates in terminals on each end.
Another type of heating tool is disclosed in U.S. Pat. No. 2,768,272. This is a tool for heat sealing thermoplastic material. It does not include a heat control, but otherwise has essentially the same parts as the tool for sealing carpets. In this patent it is simply stated that the heater shoe or plate is heated by suitable electric resistance which is not shown.
Another similar device is disclosed in U.S. Pat. No. 2,814,710. Like the device of U.S. Pat. No. 3,523,176, it includes a U-shaped heating unit which is disposed in a U-shaped recess in the heat transfer shoe. The shoe is covered with "Teflon."
U.S. Pat. No. 2,838,647 discloses a heat shield for a heat sealer of the general type employed in sealing packages in plastic film. The purpose of the shield is to provide a disposable unit to insure that at all times a smooth surface is available.
A further thermal sealing device is disclosed in U.S. Pat. No. 2,609,316. As with the other devices, it includes a handle, heating shoe or sole plate, thermostat and heating unit. The invention is directed primarily to a sole construction in which a multi-layer sole is adhesively attached to the iron.