| US5550350A | 1996-08-27 |
| 1. | A thermal walkway cover comprising a plurality of laminated flexible layers including a durable, nonslip, UV resistant top layer selected from the group consisting of rubber, a polyvinyl chloride and other plastics, an insulating, waterproof bottom layer, at least one intermediate layer between the top and bottom layers comprising an electrically heatable inner layer, means to heat the inner layer, and opposed surfaces of the layers being bonded together. |
| 2. | A cover according to claim 1, wherein the inner layer is an electrically conductive carbonized rubber. |
| 3. | A cover according to claim 2, wherein the top layer is a polyvinyl chloride and the bottom layer is a closed cell rubber. |
| 4. | A cover according to claim 2, wherein the top layer is a rubber and the bottom layer is a closed cell rubber. |
| 5. | A cover according to one of claims 3 and 4, wherein the top layer has a raised upper surface forming water drainage channels. |
| 6. | A cover according to claim 2, wherein the means to heat the carbonized rubber layer comprises a plurality of heating element strips, and means to connect the strips to an electrical power source. |
| 7. | A cover according to claim 6, wherein the heating element strips comprise copper braided strapping. |
| 8. | A cover according to claim l, wherein the cover is in the form of a module having a plurality of heating elements for heating the inner layer and at least one edge of the cover is of dovetail construction whereby a plurality of cover modules can be interlocked together. |
| 9. | A cover according to claim 6, wherein the cover is in the form of a module and at least one edge of the cover is of dovetail construction whereby a plurality of cover modules can be interlocked together. |
| 10. | A cover according to claim 8, further comprising watertight electrical connectors each connected at one end to a heating element and the other end is adapted to be connected to a corresponding connector on another module. |
| 11. | A cover according to claim 9, further comprising watertight electrical connectors each connected at one end to a heating element strip and the other end is adapted to be connected to a corresponding connector on another module. |
| 12. | A thermal walkway cover system comprising a plurality of modules according to claim 10 connected together to cover a predetermined walkway area. |
| 13. | A thermal walkway cover system comprising a plurality of modules according to claim 11 connected together to cover a predetermined walkway area. |
| 14. | A thermal walkway cover according to claim 6, wherein the cover further comprises electrically conductive metal foil layers juxtaposed to top and bottom surfaces of the inner layer to eliminate hot spots where electrical connections are made to the inner layer. |
| 15. | A method of preventing snow buildup and icing of a walkway, comprising placing over the walkway a cover comprising a durable, nonslip, UVresistant top layer, an insulating, waterproof bottom layer and at least one intermediate layer comprising an electrically heatable inner layer, and heating the inner layer to melt snow and ice accumulating on the top layer. |
| 16. | A method of preventing snow buildup and icing of a walkway, comprising placing over the walkway a cover comprising an electrically conducting inner layer, laminating to a top surface of the inner layer a durable, nonslip, UV resistant top layer, laminating to a bottom surface of the inner layer an insulating, waterproof bottom layer, and heating the inner layer to melt snow and ice accumulating on the top layer. |
| 17. | A method according to claim 16, further comprising forming the top layer from a rubber or vinyl with a raised surface forming water drainage channels, forming the inner layer from an electrically conductive carbonized rubber, and forming the bottom layer from a closed cell rubber. |
| 18. | A method according to claim 17, further comprising juxtaposing an electrically conductive metal foil to top and bottom surfaces of the inner layer thereby to eliminate hot spots where electrical connections are made to the inner layer. |
Field of the Invention This invention relates to a year around, non-slip, thermostatically controlled, radiant heated, layered flexible mat to prevent snow buildup and icing of walkways.
SUMMARY OF THE INVENTION The invention provides a non-slip, electrically powered, radiant heated, layered mat for covering outdoor walkways, having a top layer of non-slip, waterproof, UV-resistant rubber or plastic, a middle layer of carbonized rubber or of rubber or plastic with embedded electrical wiring, and a bottom insulating layer of closed cell rubber or plastic.
BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a top plan view of the thermal walkway cover showing electrical components and interlocking dovetail edge treatment.
Fig. 2 is a side elevation in cross-section showing electrical features of the invention.
Fig. 3 is a top plan view of a starter section or module of the thermal walkway cover showing the power supply.
DESCRIPTION OF PREFERRED EMBODIMENTS
In Fig. 1, the numeral 9 generally denotes a section or module of the thermal walkway cover. Cover 9 has, on all four sides thereof interlocking dovetail projections 11 and slots 12, allowing the sections or modules to be connected together in an interlocking manner, if desired to cover an area of a particular size. A watertight receptacle for electrical connection to an AC power source is denoted by the numeral 1.
A control unit of standard type (not shown) is provided between receptacle 1 and the power source to control the current to the thermal walkway cover. The numeral 2 denotes a watertight blade plug for electrical connection between mat
sections or modules. Copper braided strapping 3 conducts electrical current to a carbonized rubber middle layer 6 (Fig. 2) , thereby generating heat within the carbonized rubber layer. An electrical supply wire 4, e.g. of nickel-chromium, is provided between power source connections 1 and copper strapping 3.
Fig. 2, a cutaway section view of the thermal walkway cover, shows three layers laminated together. A top layer 5 is a durable, non-slip, UV-resistant rubber or plastic, such as vinyl, with raised surface creating drainage channels 13 across the surface, to drain water from the mat surface. As above noted, a middle layer 6 is a carbonized, electrically conductive rubber, with embedded flat copper braided strapping, and provided with watertight electrical connectors 1 and 2 and wire 4 to electrify the carbonized, electrically conductive rubber layer 6 and generate enough radiant heat to warm the top layer 5. The middle layer may comprise a non¬ conductive rubber or plastic material in which are embedded resistant-type electrical heating elements such as wires. Thermal sensors (not shown) also may be provided. A bottom layer 7 is an insulating, waterproof, closed cell rubber, designed to prevent radiant heat from the middle layer from penetrating into the ground.
As also shown in Fig. 2, the composite body 9 may also contain layers 14 of thin electrically conductive metal foil, such as copper, to help eliminate hot spots where connectors 1 and 2 are attached to the middle layer 6. In such case, the foils are soldered to the electrical supply at the respective connectors. Fig. 3 shows a starter section or module with interlocking dovetail connectors on one side only, receptacle 1 for connection to the power source, plug 2 for connection between modules, copper braided strapping 3, and Ni-Cr electrical supply wire 4.
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