Electrically heated mat

June 2, 1959

Η. B. WOLF

2,889,445

ELECTRICALLY HEATED MAT

Filed March 28, 1955

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BY

ATTORNEYS

United States Patent Office

2,889,445

Patented June 2, 1959 proved rug pad or mat is broadly designated at 10 and comprises a first outer or bottom cover or ply 11 formed from tough, glass reinforced paper, plastic, rubber or other resilient web material. Positioned upon the ply 11 5 is a thin layer or ply 12 of heat conducting metal such as aluminum foil. As is well known, foil is generally of substantially the same thickness as writing paper and the thickness thereof is proportionately exaggerated in Figure 2 for purposes of clarity.

Above the thin layer or ply 12 of heat conducting metal is placed a thin fibrous sheet or ply 13 which prevents a suitably insulated electrical conductive means or heating element 14 from engaging the metal ply 12.

Between the closely spaced parallel runs or coils of the 15 electrical conductive means 14 is placed a high thermal conducting material or ply 15 in the form of saturated felt impregnated with asphalt, matted aluminum, steel wool or the like.

An upper layer or ply 16 of heat conducting metal such 20 as aluminum foil is in direct contact with the electrical conductive means 14 and the heat conducting material 15. It should be noted that the spaced parallel runs or coils of the conductive means 14 are in continuous uninterrupted contact with the metallic ply 16 to permit the ply 25 to receive the maximum amount of heat by conduction.

A resilient ply 17 formed from tough, glass reinforced paper, plastic, rubber or other resilient web material is positioned upon the conducting metal 16 to comprise the outer or top cover portion of the pad or mat 10.

All the plies in the entire assembly are cemented together under heat and pressure by means of a high thermal.

' conducting cement such as asphalt cement or asphalt cement to which metal powder, such as aluminum or bronze, has been added to increase the conductivity.

Asphalt cement is dark colored and substantially black, and when the foil sheet 16 is coated with it to secure the sheet to the heating element 14 and the heat conducting material 15 between the parallel runs of the heating element 14, the foil sheet loses its reflecting value and be40 comes a heat conducting sheet. However, the foil sheet 12 is preferably secured to the fibrous ply 13 by the asphalt cement at spaced areas to permit the foil sheet to maintain to a considerable degree its heat reflecting quality.

Around the edge of the mat 10 is placed a water proof sealing tape 20 which provides a trim edge and a means for firmly securing an attachment cord having leads 21,22 by being wrapped therearound as shown at the lower corner portion of Figure 1. By securing the leads 21, 22 50 to the mat comer the spaced parallel runs of the electrical conducting means 14 are prevented from being pulled out of the mat or pad by any jerk or pull on the attachment cord.

Suitably insulated lead wires 21 and 22 are connected ⁶⁵ to opposite ends of the heating element 14 adjacent a corner portion of the mat or pad 10 and are provided with a suitable plug 23 which is adapted to be connected to a suitable source of electrical energy.

In operation the heat generated in the electrically in00 sulated coiled conductive member 14 of the pad is transmitted in three directions as follows:

To tlie upper thin metal sheet 16 by conduction since the upper sheet is in contact with it; to the heat conducting material 15 on each side of the electrical conductive means 65 14 and thence to the upper thin metal sheet 16 which is in direct contact with conductive material 15; through the lower fibrous sheet 13 to the lower thin metal sheet 12 where a large portion of the heat is reflected upwardly and the remainder conducted downward to the floor or 70 surface upon which the mat may be used.

Accordingly, it will be understood that heat generated in the conductive means 14 is conducted readily to the

2,889,445

ELECTRICALLY HEATED MAT

Herman B. Wolf, Charlotte, N.C.

Application March 28,1955, Serial No. 497,007

Claims. (CL 219—46)

This invention generally relates to floor coverings and, more especially, to an improved rug or carpet warming or heating mat or pad for disposition beneath the rug, carpet or the like for transmitting heat thereto.

Heretofore, various attempts have been made to develop a heating pad suitable for underlining floor coverings, such as rugs, carpets and the like, which would give even heating of the upper surface of the heating pad and a low temperature gradient between the heat source and the surface of the pad. However, all attempts in this direction have met with failure.

It is therefore the primary object of this invention to provide an improved heating pad or mat having a construction which results in even heating of the upper surface of the pad and a low temperature gradient between the heat source and the surface of the pad without sacrificing the desired resiliency and thinness of the pad. This construction also prevents localized hot spots under flat pieces of furniture or other flat objects that might be placed on the heating pad since the heat conducting metal and material in the pad conduct the heat evenly throughout the pad.

It is another object of the invention to construct a heating pad wherein heat is conducted readily to the upper surface of the pad by a thin metal sheet positioned above and in contact with the heating conductors and through heat conducting material placed on each side of the electrical conducting means and in contact with the thin metal sheet thereabove.

It is also an object to prevent a downward dissipation of heat in the pad by placing a thin metal sheet in spaced relationship to the underside of the heat generating means to reflect the heat upward to the top surface of the pad.

It is a further object to provide a multi-ply heating pad or mat wherein the cement means for bonding together the various plies is a heat conducting cement which facilitates the obtaining of an even temperature on the upper surface of the mat.

This application is a continuation-in-part of application, Serial Number 397,906, which is now Patent Number 2,783,358.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds, when taken in connection with the accompanying drawings, in which—

Figure 1 is a plan view of the improved electrically heated pad or mat showing a corner of the uppermost ply thereof rolled upon itself with others of the ply and portions of the coils of the heating element being broken away for purposes of clarity;

Figure 2 is an enlarged fragmentary vertical section through the improved pad or mat taken along line 2—2 of Figure 1;

Figure 3 is an enlarged fragmentary vertical section through the improved pad or mat taken along line 3—3 in Figure 1 showing the manner in which the comer portions of the pad or mat are secured.

Referring more specifically to the drawings, the im2,880,446 ό

upper surface of the mat 10 both through direct contact of the conductive means 14 with the upper thin metal sheet 16 and also to the upper metal sheet 16 through the heat conducting material 15 on each side of the electrical conducting means 14. This results in even heating of the upper surface of the mat or pad 10 and a low temperature gradient between the heat source and the surface of the mat. This construction also prevents localized hot spots under flat pieces of furniture or other flat objects as the heat conducting metal 16 and heat conducting material 15 conduct the heat evenly throughout the mat.

The employment of a heat conducting cement for bonding the various plies together aids in obtaining a uniformly heated upper pad surface.

It is thus seen that there is provided a novel floor covering, a preferred form of which may be in the nature of the rug mat or pad for disposition beneath the decorated floor covering and which is arranged to effectively accommodate and conceal both from sight and feel, electrical resistance means or heating element coils, and means for diffusing heat uniformly throughout the rug or mat without sacrificing the resiliency of the rug pad and, further, being so arranged and constructed as to effectively radiate the heat upwardly or away from the floor so that substantially all the heat is effectively utilized and not dissipated or conducted away by the floor.

It is also contemplated that the improved heating pad or mat construction may, in itself, constitute a suitable flooring covering and serve as a visible covering member. 30

In the drawings and specification there has been set forth a preferred embodiment of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only, and not for purposes of limitation, the scope of the invention being defined in ³⁵the claims.