Modular heated platform

Abstract

A platform to be arranged adjacent to another platform to collectively form a heated walkway that minimizes the formation of ice on a surface of the walkway that is exposed to a sub-freezing environment. The platform includes an outermost surface to be exposed to the sub-freezing environment for providing traction for pedestrians walking on the platform, and a heating element for generating thermal energy to be transmitted to the outermost surface for minimizing the formation of ice on the outermost surface. A fastener is also provided for coupling the platform to a compatible feature of an adjacent platform to collectively form a walkway, and an electrical conductor delivers electric energy to the heating element and conducts electric energy from an external energy source to an adjacent platform.

Description

FIELD OF THE INVENTION

The present invention relates to a heating device and use thereof. More particularly, the present invention relates to a platform provided with a heated surface that minimizes ice formation on the platform. A walkway can be assembled from a plurality of interlocking modular platforms.

BACKGROUND OF THE INVENTION

Typically, external flooring surfaces such as sidewalks and stair treads exposed to cold weather accumulate ice in on the exposed surface upon which people walk. This makes walking dangerous, and often requires the ice to be removed at the expense of the property owner. The cost of ice removal is particularly high for the owners of public facilities having significant amounts of external flooring such as sidewalks, courtyards, external vending spaces, parking lots, and the like.

Of particular relevance to the present invention, sidewalks are commonly encountered by pedestrians walking in icy conditions. Conventional heated sidewalks typically include tubular passages embedded within the concrete poured to initially create the sidewalk. Steam is transported through the tubular passages to generate the thermal energy required to heat the exposed walking surface of the sidewalk. The thermal energy from the steam is conducted from within the concrete to the exposed walking surface, thereby raising the temperature of the walking surface above the freezing point of water.

The conventional steam-heated sidewalks, however, require a constant supply of steam to minimize the formation of ice on the walking surface of the sidewalk. This is particularly true during prolonged periods of cold weather. But since sidewalks are somewhat permanent structures, repairing and/or replacing the steam-heating system when a disruption of steam delivery occurs is time consuming, labor intensive and expensive.

Accordingly, there is a need in the art for heated flooring that can minimize the accumulation of ice on an external walking surface and that overcomes the limitations of the prior art.

SUMMARY OF THE INVENTION

According to one aspect, the present invention provides a platform to be arranged adjacent to another platform to collectively form a heated walkway that minimizes the formation of ice on a surface of the walkway that is exposed to a sub-freezing environment. The platform includes a tread with an outermost surface to be exposed to the sub-freezing environment for providing traction for pedestrians walking on the platform, and a heating element for generating thermal energy to be transmitted to the tread for minimizing the formation of ice on the outermost surface. A fastener can be used to couple the platform to a compatible feature of an adjacent platform to collectively form a walkway, and an electrical conductor for delivers electric energy to the heating element and from an external energy source to an adjacent platform.

According to another aspect, the present invention provides a heated walkway for minimizing the formation of ice on a surface of the walkway to be exposed to a sub-freezing environment and upon which pedestrians can walk. The walkway includes a first platform and second a second platform. The first platform comprises a first heating element for generating thermal energy to be transmitted to the surface of the walkway for minimizing the formation of ice on the surface, and a fastener for coupling the first platform to the second platform to maintain the position of the first platform relative to the second platform. The first platform also includes an electrical conductor for delivering electric energy to the first heating element and conducting electric energy between an external energy source and the second platform. The second platform includes a second heating element for generating thermal energy to be transmitted to the surface of the walkway for minimizing the formation of ice on the surface, and a second fastener that is compatible with the first fastener. Similar to the first platform, the second platform also includes an electrical conductor for delivering electric energy to the second heating element and conducting electric energy between the first platform and a third platform.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the present invention will become apparent to those skilled in the art to which the present invention relates upon reading the following description with reference to the accompanying drawings, in which:

FIG. 1 is a top view of a platform in accordance with an embodiment of the present invention;

FIG. 2 is a bottom view of a platform in accordance with an embodiment of the present invention;

FIG. 3 is a top view of a walkway comprising a plurality of platforms in accordance with an embodiment of the present invention;

FIG. 4 is a cross-sectional view of the platform shown in FIG. 1 taken along line 4-4; and

FIG. 5 is a schematic illustration of a resistive heating element in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Certain terminology is used herein for convenience only and is not to be taken as a limitation on the present invention, which is set forth in the appended claims. Any relative language used herein, such as an “outermost surface,” is to be interpreted in view of the those relationships as shown in the drawings. Further, in the drawings, certain features may be shown in somewhat schematic form.

FIG. 1 is a top view of a heated platform 10 in accordance with an embodiment of the present invention. The platform 10 can be arranged adjacent to one or more other platforms 10 to collectively form a heated walkway that minimizes the formation of ice on a surface of the walkway that is exposed to a sub-freezing environment, as described in detail below. The term “walkway” is used herein to refer to any surface upon which pedestrians can walk, such as sidewalks, stairs, ramps, parking lots, driveways, and the like.

In general, the platform 10 includes a generally rectangular or square base 11 made from a rigid plastic that has favorable thermal properties. The favorable thermal properties include resistance to brittleness and breakage over a wide range of temperatures, as well as suitable insulation to minimize the loss of thermal energy generated by a heating element 22 (FIG. 4) to the ground supporting the platform 10. Although the illustrative embodiments are described and illustrated in the drawings as square, 4 ft×4 ft platforms, the present invention encompasses all shapes in addition to square, including triangular, pentagonal, hexagonal, trapezoidal, and the like. All of these shapes can be interlocked into a lattice of platforms 10 to establish a generally-uniform walkway without significant spaces between platforms 10.

As shown in FIG. 1, the platform includes a tread 14 with an outermost surface 18 (FIG. 4) that will be exposed to a sub-freezing environment during certain times of the year depending on the geographic location. The tread 14 can optionally be removable and replaceable, and can optionally be provided with a texture or other traction-enhancing feature on its outermost surface to provide pedestrians with traction while they are walking on the platform. Examples of suitable traction-enhancing features include grit, contours, and the like. This, in addition to the heat generated by the heating element 22 (FIGS. 4 and 5) serve to minimize the likelihood that pedestrians will lose traction and slip while walking on the platform 10.

Fasteners 26a, 26b extend outwardly from the sides of the platform 10 for coupling the platform 10 to a compatible fastener 26a, 26b of an adjacent platform 10. Assembling the platforms 10 in this manner allows for the formation of a floor, sidewalk, ramp, stair, or other type of surface as desired. For the embodiment shown in the drawings, particularly FIGS. 1 and 4, it can be seen that the fastener 26a includes an inclined surface with a protruding rail 29a and a similarly-sized impression 32a. Likewise, the compatible fastener 26b also includes an inclined surface 27b with a protruding rail 29b and a similarly-sized impression 32a. The primary difference between the fasteners 26a, 26b is that the inclined surface 26a is complementary to the inclined surface 26b. Thus, when two or more platforms 10 are positioned adjacent to each other to form a walkway 36 or other floor-type surface as shown in FIG. 3, the inclined surface 27a opposes the inclined surface 27b. Further, when the walkway is formed, the protruding rail 27a is disposed within the compatible impression 32b and the protruding rail 27b is disposed within the compatible impression 32a. Such features promote proper alignment of the plurality of platforms 10 to allow for proper alignment of the conductors of electric energy, shown in FIG. 2. Locking pins (not shown) can be inserted through keyhole apertures 39 formed in the fasteners 26a, 26b in each platform 10, said keyhole apertures 39 being aligned when the platforms 10 are assembled. The locking pins fix the relative position of one platform 10 another platform 10 when aligned to form the walkway 36.

A heating element 22, such as that shown in FIG. 5 for example, is provided to the platform 10 to generate thermal energy for minimizing the formation of ice on the platform in a sub-freezing environment. The thermal energy generated by the heating element 22 is transmitted by conduction, convection, radiation, any other mechanism or combination thereof to the outermost surface 18 of the tread. Due to the supply of thermal energy by the heating element, the outermost surface 18 of the tread is maintained at a temperature above the freezing temperature of water, which is approximately 0° C., or 32° F. at sea level.

The heating element 22 shown in FIG. 5 is an electronic resistive heating element, but the present invention encompasses any heat-generating device that can convert electric energy into thermal energy. The resistive heating element 22 includes an array of metallic conductors 42 supported by a flexible, dielectric substrate 45. Electric energy is supplied to and from the array of conductors 42 by leads 48 that conduct electric energy transported by the power-supply lines 52 (FIG. 2) of the platform 10. Due to the resistance of the conductors 42, at least a portion of the electric energy delivered to the conductors 42 is converted into the thermal energy that is eventually transmitted to the outermost surface 18 of the tread 14.

A flexible heating element 22 such as that shown in FIG. 5 allows for location of the heating element at a variety of locations throughout the platform 10. The embodiment shown in FIG. 4 discloses one suitable location for the heating element 22 relative to the other features of the platform 10. In FIG. 4, the heating element 22 is disposed between the tread 14 and the base 11 of the platform 10. This offers at least two advantages to other locations within or on the platform 10. First, the tread 14 provides a degree of protection to the heating element 22 from the sub-freezing environment as well as the forces imparted on the platform 10 by pedestrians as they walk on the platform 10. And second, the base 11 provides thermal insulation between the heating element 22 and the ground supporting the platform 10. Although suitable thermal insulation can be provided by the base 11 with the heating-element in a variety of locations, one embodiment of the present invention provides for a ratio of: $\frac{\begin{array}{c}\mathrm{Overall}\mathrm{Heat}\mathrm{Transfer}\mathrm{Coefficient}\\ \mathrm{of}\mathrm{the}\mathrm{Thermall}\mathrm{PathFrom}\mathrm{the}\mathrm{Heating}\\ \mathrm{Elementto}\mathrm{the}\mathrm{Outermost}\mathrm{Surface}\end{array}}{\begin{array}{c}\mathrm{Overall}\mathrm{Heat}\mathrm{Transfer}\mathrm{Coefficient}\mathrm{of}\mathrm{the}\\ \mathrm{Thermal}\mathrm{Path}\mathrm{from}\mathrm{the}\mathrm{Heating}\mathrm{Element}\mathrm{to}\\ \mathrm{the}\mathrm{Surface}\mathrm{Supporting}\mathrm{the}\mathrm{Platform}\end{array}}\times 100\%\le 20\%$

Other embodiments include a heating element 22 supported on the outermost surface 18 of the tread 14, integrating the heating element 22 within the tread 14, and integrating the heating element 22 directly into the material used to create the base 11 of the platform 10. For embodiments expose the heating element 22 to the ambient environment, the term “outermost surface” refers to the outermost surface of the heating element, and not the outermost surface of the tread 14. In any event, the outermost surface 18 is used herein to refer to the surface of the platform 10 that will be exposed to the sub-freezing environment and upon which ice formation can occur.

Electric contacts 56 also extend through the fasteners 26a, 26b to facilitate the conduction of electric energy from one platform 10 to another when the to platforms 10 are coupled together to form the walkway 36. Each contact 56 is made from a conductor of electricity, such as a metal, and conducts electric energy from an external power source and/or another platform 10 to the power-supply lines 52, shown in FIG. 2. Each contact can optionally include a quick-disconnect plug allowing for rapid connection or disconnection of the contacts to an external source of electric energy or another platform 10.

The location of the contacts 56 are uniform such that when the fasteners 26a, 26b overlap when the platforms 10 for a walkway 36, the contact 56 in a fastener 26a of a first platform 10 is in contact with a contact 56 in a fastener 26b of a second platform 10. Thus, when the platforms 10 are assembled to form a walkway 36, the electric energy supplied by a common external energy source can be conducted to all platforms 10 in the walkway 36 without the need for a dedicated wiring system aside from that provided to each platform 10. Accordingly, the power-supply lines 52 are electrical conductors that deliver electric energy to the heating element 22 and conduct electric energy from an external energy source to an adjacent platform 10.

To somewhat automate control of the heating-element provided to a platform 10, a temperature sensor and thermostat (not shown) can optionally be provided to the platform 10. The temperature sensor can be disposed anywhere within or on the platform 10, and even remotely from the platform 10 from where it can sense a temperature indicative of whether ice is likely to form on the outermost surface 18 of the tread 14, where the ambient temperature can be below the freezing temperature of water. For instance, the temperature sensor can be concealed beneath the outermost surface 18 of the tread 14, between the tread 14 and the heating element 22, or anywhere else on the platform 10. Regardless of where the temperature sensor is installed, the temperature measure by the temperature sensor is to be correlated to the temperature of the outermost surface 18. Other embodiments include the use of an infrared temperature sensor.

Operation of a thermostat can automatically respond to changes in the temperature of the outermost surface 18 (either calculated base on an indirect temperature measurement by the temperature sensor or measured directly by the temperature sensor) to activate, deactivate, and prolong or shorten the duration of operation of the heating element 22 as appropriate. If, for example, significant ice accumulation is suspected due to a prolonged period of sub-freezing ambient temperatures, the thermostat can activate and ensure a sufficient duration of activation of the heating element 22 to heat the outermost surface 18.

A temperature sensor can be provided to each platform 10 making up a walkway 36, a group of platforms forming a region of a walkway 36, an entire walkway, or any other arrangement. Likewise, a thermostat can be assigned the task of controlling operation of the heating element 22 of each single platform 10 in a walkway 36, a plurality of platforms 10 in a walkway 36, or the entire walkway 36. Thus, each platform 10 in a walkway 36 can be individually controlled, controlled as part of a region of platforms 10, or controlled as the entire walkway 36.

From the above description of the invention, those skilled in the art will perceive improvements, changes and modifications. Such improvements, changes and modifications within the skill of the art are intended to be covered by the appended claims.

Claims

1. A platform to be arranged adjacent to another platform to collectively form a heated walkway that minimizes the formation of ice on a surface of the walkway that is exposed to a sub-freezing environment, the platform comprising:

an outermost surface to be exposed to the sub-freezing environment for providing traction for pedestrians walking on the platform;

a heating element for generating thermal energy to be transmitted to the outermost surface for minimizing the formation of ice on the outermost surface;

a fastener for coupling the platform to a compatible feature of an adjacent platform to collectively form a walkway; and

an electrical conductor for delivering electric energy to the heating element and conducting electric energy from an external energy source to an adjacent platform.

2. The platform according to claim 1 further comprising a temperature sensor for sensing a temperature indicative of whether ice is likely to form on the surface of the tread that is to be exposed to the sub-freezing environment.

3. The platform according to claim 2, wherein the temperature sensed by the temperature sensor is a temperature of the surface of the tread that is to be exposed to the sub-freezing environment.

4. The platform according to claim 2 further comprising a thermostat for controlling operation of the heating element as a function of the temperature sensed by the temperature sensor.

5. The platform according to claim 1, wherein the heating element is integrated within the tread.

6. The platform according to claim 1, wherein the heating element is an electric, resistive heating element.

7. The platform according to claim 1 further comprising a connector that cooperates with a compatible connector provided to an external energy source upon placement of the platform adjacent to the external energy source.

8. The platform according to claim 1, wherein the heating element and electrical conductor are integrated within the platform, thereby forming a modular platform that can be replaced as a unit.

9. The platform according to claim 1, wherein the platform is formed into at least one of a sidewalk, a ramp, and a stair.

10. A heated walkway for minimizing the formation of ice on a surface of the walkway to be exposed to a sub-freezing environment and upon which pedestrians can walk, the walkway comprising a first platform and second a second platform, wherein the first platform comprises:

a first heating element for generating thermal energy to be transmitted to the surface of the walkway for minimizing the formation of ice on the surface;

a fastener for coupling the first platform to the second platform to maintain the position of the first platform relative to the second platform; and

an electrical conductor for delivering electric energy to the first heating element and conducting electric energy between an external energy source and the second platform;

and wherein the second platform comprises:

a second heating element for generating thermal energy to be transmitted to the surface of the walkway for minimizing the formation of ice on the surface;

a second fastener that is compatible with the first fastener; and

an electrical conductor for delivering electric energy to the second heating element and conducting electric energy between the first platform and a third platform.

11. The walkway according to claim 10, wherein the first and second platforms each further comprise electrical contacts that engage each other upon positioning the first platform adjacent to the second platform to conduct electric energy between the first and second platforms.

12. The walkway according to claim 10, wherein at least one of the first platform and the second platform further comprises a temperature sensor for sensing a temperature indicative of whether ice is likely to form on the surface of the walkway that is to be exposed to the sub-freezing environment.