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US 4,967,057 AGranted
Snow melting heater mats
OwnerRonald E. Bayless, James M. Havardinventors
Life of this patent
Estimating the term…
Abstract
Individual electrically heated mats, self-regulated by use of an electrical element whose resistance varies proportionately with its temperature, used for covering walking areas to prevent accumulation of snow and ice. Each mat is provided with male and female electrical connections on the ends of short power cords to permit any number of mats to be chained together in electrical parallel and to be used to cover, for example, a flight of stairs by positioning one mat on each stair.
Claims21
A flexible heating mat for preventing the accumulation of snow or ice on a walkway comprising:
- a flat flexible mat casing having upper and lower surfaces, a single flexible elongated heating strip of small cross section sealed within said casing, a first flexible electric cord power entering an edge of the casing near a first side thereof and generally coplanar with the mat at said edge, said first cord having a male electric plug thereon for connecting the heating strip to a source of power, said heating strip comprising two parallel closely and uniformly spaced electric conductors extending the entire length of the strip with electrically resistive material electrically interconnecting said conductors throughout said length, said cord being electrically connected to said conductors at one end of said heating strip within the mat casing, said conductors and the resistive material therebetween each having a serpentine configuration and being coplanar throughout the mat and oriented in a plane parallel to the plane of the mat when it is on a flat surface.
A heating mat for preventing the accumulation of snow or ice on a walkway comprising:
- a flat flexible mat casing having upper and lower surfaces, a flexible heating strip sealed within said casing, a first flexible electric cord entering an edge of the casing near a first side thereof and generally coplanar with the mat at said edge, a second electric cord entering the edge of the mat near an opposite side thereof, said cords being electrically connected to each other and to only one end of said heating strip within the mat casing, said first cord having a male electric plug thereon for connecting the heating strip to a source of power, said second cord having a female connector for connection to an electric plug like said male electric plug, the length of said second cord being less than the height of the riser of one stair step so that the female connector hangs above the next lower walkway surface when the mat is positioned on a walkway step.
A flexible heating mat for preventing the accumulation of snow or ice on a walkway comprising:
- a flat flexible general rectangular mat casing having upper and lower portions forming external mat surfaces, a single flexible elongated heating strip of small cross section sealed within said casing and capable of providing uniform heating over the entire area of the upper external surface of the mat, said strip comprising throughout its length an electrically insulating sheath enclosing a pair of closely and uniformly spaced electric conductors with electrically resistive material therebetween, said resistive material having a positive temperature coefficient, a first flexible electric cord entering an edge of the casing close to a corner and at a first side thereof and generally coplanar with the mat at said edge, said cord being electrically connected to each of said conductors at one end of said heating strip within the mat casing, said first cord having a male electric plug thereon for connecting the heating strip to a source of power, a second electric cord having a portion entering an edge of the casing close to a second corner thereof with the second cord portion extending from the casing generally coplanar with the mat, said second cord being electrically connected to the first cord within the mat casing, said second cord having a female connector for connection to an electric plug like said male electric plug, an electrically conducting grounding layer means of good heat conductivity extending in intimate heat conducting relationship and in contact with the outer surface of the heating strip over the entire area of the heating strip between the strip and said upper casing portion, and means for connecting said grounding layer to an electrical ground externally of said mat.
Dependencies are inferred from the claim text.