Stretcher cavities of the present invention can be manufactured from many different materials, including but not limited to, polymers, metals, composites, foams, fiberglass, wood, KEVLAR, coated paperboard, and combinations thereof. Preferably, the stretcher is made from a material comprising a polymer, such as, for example high-density polyethylene. Any known techniques for forming three-dimensional structures from the list of materials above can be employed for manufacturing the stretcher components.
In preferred embodiments, the cavity is injection molded or rotational molded. Utilizing a rotational molding technique can yield a hollow double-wall configuration. Filler material may be disposed between first wall and second wall to impart added strength, and insulation and flotation properties. A representative, non-limiting list of filler material includes air, foam, natural and synthetic fibers, and wood products. Preferably, the filler material is a liquid foam, such as catalyzed urethane foam, that is injected into the double-wall configuration with techniques such as reaction injection molding.
Design features, materials, and manufacturing techniques as described above may be selectively combined to provide various beneficial properties, such as, for example, x-ray translucency and floatation. Ambulance Stretcher of the present invention are preferably floatable without a load, more preferably floatable with a load of about 200 pounds residing in the cavity, and most preferably floatable containing a load of up to about 350 pounds, all in the absence of retrofitted (additional) flotation aids.
It is to be understood that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure, manufacture of, and function of the invention, the disclosure is illustrative only. Accordingly, changes may be made in detail, especially in matters of shape, size and arrangement of structural features, as well as, sequences of manufacturing steps, within the principles of the stretcher to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.