CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 61/389,122 filed October 1, 2010, and entitled BI-LAYER COIL INCLUDING NON-METALLIC MATERIAL, and U.S. Provisional Patent Application No. 61/487,227 filed May 17, 2011, also entitled BI-LAYER COIL INCLUDING NON- METALLIC MATERIAL.

BACKGROUND OF THE INVENTION

Field of the Invention

[0002] The present disclosure relates generally to temperature-sensitive devices that move in response to changes in temperature.

Description of the Related Art

[0003] Many types of temperature- sensitive devices exist in the art. Temperature-sensitive devices with two or more layers (e.g., strips) of metal laminated, bonded, or otherwise joined to each other, often referred to as a bi-metallic or bi-metal strip, are known. Bi-metallic strips have two metal layers having different coefficients of thermal expansion relative to each other, causing the bi-metal strip to change its shape (e.g., flex, bend or otherwise move) in response to a change in temperature. Bi-metallic strips have been used in various configurations, such as small, rectangular strips or tabs, or coils. However, it is difficult to design a temperature- sensitive device that is simple and inexpensive to use and manufacture.

[0004] There are several types of coefficients of thermal expansion: volumetric, area and linear. For solid materials, the linear thermal expansion coefficient relates the change in a material's linear dimensions to a change in temperature. The linear thermal expansion coefficient is the fractional change in length per degree of temperature change, and can be expressed by the formula wherein L is the linear dimension (e.g., length) of the material for which the linear coefficient of thermal expansion 0CL is being measured, and dL/dT is the rate of change of that length with temperature. The area thermal expansion coefficient is the fractional change in area per degree of temperature change, and can be given by the formula wherein A is the area of the material for which the area thermal expansion coefficient 0CA is being measured, and dA/dT is the rate of change of that area with temperature. The volumetric coefficient of thermal expansion is the fractional change in volume per degree of temperature change, and can be given by the formula 0C _v =(l/V)(dV/dT), wherein V is the volume of the material for which the volumetric coefficient of thermal expansion oc _v is being measured, and dV/dT is the rate of change of that volume with temperature. As used herein, the "coefficient of thermal expansion" can refer to any of these types of coefficients of thermal expansion.

SUMMARY

[0005] The present application provides novel and nonobvious bi-layer strips useful for detecting, measuring, and/or recording values of environmental parameters. While the application focuses primarily on bi-layer strips used for detecting temperature, it will be appreciated that embodiments of the described strips and devices may be used for detecting other parameters, such as, for example, humidity.

[0006] One embodiment provides a temperature-sensitive device comprising first and second layers. The first layer comprises a non-metallic material, and the second layer has a different coefficient of thermal expansion than the first layer. The first and second layers are joined together and form a coil with two or more loops.

[0007] In some embodiments, the temperature-sensitive device further comprises at least one linking member. The linking member is configured to link a portion of the coil to a portion of a device for monitoring or reacting to an environmental condition. In some embodiments, the at least one linking member is configured to movably engage with the coil.

[0008] Another embodiment provides a temperature-recording device comprising a body, a temperature- sensitive element, and a recording component. The temperature-sensitive element comprises first and second layers. The first layer comprises a non-metallic material. The first and second layers have different coefficients of thermal expansion relative to each other. The first and second layers are joined together to form a coiled, multi-layer, temperature- sensitive strip that moves in response to changes in temperature of the strip. The recording component is configured to convert the position and/or movement of the strip into temperature data. The recording component is configured to record the temperature data onto a tangible medium or a computer-readable memory.

[0009] Another embodiment provides an apparatus comprising a body, a temperature-sensitive element, and a controlled device. The temperature- sensitive element comprises first and second layers. The first layer comprises a non-metallic material. The first and second layers have different coefficients of thermal expansion relative to each other. The first and second layers are joined together to form a coiled, multi-layer, temperature-sensitive strip that moves in response to changes in temperature of the strip. At least a portion of the strip is linked to the body. The controlled device is configured to be actuated by the temperature-sensitive strip when the temperature- sensitive strip moves in response to changes in temperature of the strip.

[0010] For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention have been described above and as further described below. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.

[0011] All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments having reference to the attached figures, the invention not being limited to any particular preferred embodiment(s) disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The appended drawings are schematic, not necessarily drawn to scale, and are meant to illustrate and not to limit embodiments of the invention.

[0013] FIG. 1 shows a side view of an embodiment of a temperature- sensitive coil.

[0014] FIG. 1A shows a side view of an embodiment of a temperature- sensitive device comprising a nested coil system. [0015] FIG. 2 shows a cross-sectional view of an embodiment of the temperature-sensitive coil of FIG. 1, taken along line 2-2 of FIG. 1.

[0016] FIG. 3 is an expanded side view of a portion of the temperature- sensitive coil of FIG. 1, said portion indicated by line 3 of FIG. 1.

[0017] FIG. 4 is an expanded side view of a portion of the temperature- sensitive coil of FIG. 1, said portion indicated by line 4 of FIG. 1.

[0018] FIG. 5 shows a top-side perspective view of an embodiment of a temperature-recording device in an open position, employing an embodiment of the temperature-sensitive coil shown in FIG. 1.

[0019] FIG. 6 shows a top-side perspective view of the temperature-recording device of FIG. 5 in a closed position.

[0020] FIG. 7A shows an expanded side view of an embodiment of a portion of the temperature- sensitive coil of FIG. 1, said portion indicated by line 3 of FIG. 1.

[0021] FIG. 7B shows an expanded side view of an embodiment of a portion of the temperature- sensitive coil of FIG. 1, said portion indicated by line 4 of FIG. 1.

[0022] FIG. 8A shows a cross-sectional view of an embodiment of the temperature-sensitive coil of FIG. 1, taken along line 8-8 of FIG. 7A.

[0023] FIG. 8B shows a different cross-sectional view of an embodiment of the temperature- sensitive coil of FIG. 1, taken along line 8-8 of FIG. 7A.

DETAILED DESCRIPTION

[0024] The present disclosure relates generally to temperature- sensitive devices. Certain embodiments relate to temperature-recording devices employing a temperature-sensitive device. Certain embodiments relate to temperature- sensitive devices in a coiled shape. Certain embodiments relate to temperature-sensitive devices comprising two or more layers of non-metallic material.

[0025] Various designs of monitoring devices have been developed to sense and respond to an environmental condition, such as temperature-sensitive devices that sense and respond to temperature. For example, temperature- sensitive devices with two or more layers (e.g., strips) of metal laminated, bonded, or otherwise joined to each other, often referred to as a bi-metallic or bi-metal strip, are known. Bi-metallic strips typically have two metal layers having different coefficients of thermal expansion relative to each other, causing the bi-metal strip to change its shape (e.g., flex, bend or otherwise move) in response to a change in temperature. The change in shape occurs because the two metals have different rates of thermal expansion and contraction. Bi-metallic strips have been used in many various known temperature-control devices and systems. However, bimetallic strips can be heavy, expensive, and difficult to manufacture. Additionally, the material characteristics of bi-metallic strips may be limited or precluded from certain applications, including, for example, applications that benefit from non-conductive materials, high purity materials (e.g., food and clean-room applications), toys (e.g., childrens' toys), and the like.

[0026] Limited configurations of temperature- sensitive devices have been developed that employ similar principles as a bi-metallic strip, but using non-metallic layers. For example, U.S. Patent No. 5,928,803 to Yasuda discloses a flat temperature- sensitive reversibly deformable laminate comprising some materials other than metal. However, it is difficult to reliably bond the layers in conventional non-metallic temperature-sensitive devices such that the layers do not delaminate over time. Additionally, it is difficult to reliably form non-metallic temperature-sensitive devices into certain shapes and configurations (e.g., a coiled shape). In particular, it is difficult to form non-metallic temperature- sensitive devices into certain shapes and configurations that can operate (e.g., flex and/or move in response to a temperature change) within certain temperature ranges (e.g., a range proximate to, or including room temperature). Thus, conventional non-metallic bi-material devices have been limited to few shapes and configurations, and have not included, for example, a coiled shape.

[0027] The disclosed embodiments provide a simple and inexpensive temperature-sensitive device that comprises two or more layers of non-metallic material with different coefficients of thermal expansion. In some embodiments, the device can form a coil, or coiled shape, with one or more loops. In some embodiments, the device can form a coil, or coiled shape, with two or more loops. The disclosed embodiments can be used in many applications, such as clocks, dryers (e.g., hair or clothes), heaters (e.g., house or water heaters), cooling devices (e.g., air-conditioners; refrigerators), thermometers, thermostats, switches (e.g., circuit breakers), valves and other actuators and control systems. The disclosed embodiments can be used in a temperature- actuated device to actuate such switches, valves and other actuators and control systems. Some embodiments can be used in the aforementioned applications that might otherwise preclude or limit the use of bi-metallic strips, such as non-conductive applications, high purity applications (e.g., food or drug-industry use, medical devices, or electronic device fabrication, such as clean-room applications), toys (e.g., childrens' toys), and the like.

[0028] In some embodiments, the layers are sonically bonded to each other. In some embodiments, the device maintains an approximately coiled shape within a certain temperature range (e.g., proximate to or spanning room temperature). The device can be configured such that it moves (e.g., deforms), in response to a change in temperature of the device. In some embodiments, the temperature-sensitive device can be employed within a temperature-recording device, such as a strip-chart recorder. It should be understood that the disclosed embodiments present examples of the present inventions for illustrative purposes, and that the scope of the present inventions is not limited to the embodiments disclosed herein.

[0029] FIG. 1 shows a side view of an embodiment of a temperature- sensitive device 10. FIG. 2 shows a cross-sectional view of an embodiment of a temperature- sensitive device 10 taken along line 2-2 of FIG. 1.

[0030] Referring to both FIGS. 1 and 2, device 10 can comprise a first layer 20 of material bonded to a second layer 30 of material at a bonding interface 40 between the first layer 20 and second layer 30, to form a bi-material structure. As described further herein, at least one of, and in some embodiments both, layers 20, 30 can comprise a non- metallic material. Layers 20, 30 can be bonded to form bi-material structures of various configurations, such as sheets, strips, coils, and the like. First layer 20 can comprise a different coefficient of thermal expansion relative to second layer 30, such that device 10 can move in response to a change in temperature of device 10, as described further herein.

[0031] Referring to FIG. 1, device 10 can comprise a coil 50 that can include a portion of layers 20 and 30 that has been bonded together (e.g., to form a strip 25), and configured to form one or more loops around (e.g., coiled, or wound around) a central axis 60a. It will be understood that coil 50 is shown and described herein as comprising a strip 25 for illustrative purposes only, and that coil 50 is not limited to a bi-material structure of a particular dimensional limitation (e.g., width). Coil 50 could be formed, for example, from a laminated or bonded sheet of layers 20, 30.

[0032] As used herein, "loop" refers to a portion of coil 50 that extends around a first, central axis 60a approximately 360 degrees between a first point (e.g., point 61) and a second point (e.g., point 62) positioned along coil 50. For illustrative purposes, coil 50 is shown with four loops 66, 67, 68 and 69, extending between points 61 and 62, 62 and 63, 63 and 64, and 64 and 65, respectively, and intersecting a plane 60b in which the axis 60a extends. Two or more loops in coil 50 can be approximately coplanar, for example, wherein the two or more loops are coplanar with or parallel to plane 60b. In some embodiments, a loop can transition from a smaller radius to a larger radius around axis 60a (e.g., from point 61 to 62 on loop 66, as illustrated in FIG. 1). In some embodiments, two or more loops of coil 50 are not coplanar (e.g., if coil 50 extends along axis 60a). In some embodiments, a loop can comprise an approximately constant radius (e.g., if coil 50 extends along axis 60a, but with a substantially constant radius relative to axis 60a). In some embodiments, one or more substantially non-coplanar loops can transition from a smaller radius to a larger radius, to form a conical-shaped coil.

[0033] It will be understood that coil 50 is shown with four loops 66-69 for illustrative purposes only. Coil 50 can be configured to have various numbers of loops, such as between about 1 and about 12 loops, or more narrowly, between about 3 and about 10 loops, or even more narrowly, between about 4 and about 8 loops. In some embodiments, coil 50 can comprise one or more loops. In some embodiments, coil 50 can comprise at least two or more loops.

[0034] Coil 50 can have many different lengths. As used herein, the length of coil 50 is defined as the length of layers 20, 30 (e.g., the length of strip 25) if extended linearly in an uncoiled state. In certain embodiments, the length of coil 50 can range from approximately 1 inch to 25 inches, or more narrowly, from approximately 5 inches to 21 inches, or even more narrowly, from approximately 10 to 16 inches.

[0035] Coil 50 can be configured to have many different diameters (i.e., the diameter of the outermost loop, illustrated here as loop 69). In certain embodiments, the diameter of coil 50 can range from approximately 0.25 inches to 5 inches, or more narrowly, from approximately 1 inch to 4 inches, or even more narrowly, from approximately 2 to 3 inches.

[0036] The length, diameter, and/or the number of loops in coil 50 can be selected (along with the type of material used) such that coil 50 can move in response to temperature changes, as described further herein. The length, diameter, and/or the number of loops in coil 50 can be selected to vary the force with which coil 50 can move, and/or the distance of such movement, in response to a temperature change of device 10.

[0037] In some embodiments, device 10 can comprise one or more coils attached to each other to vary the force with which device 10 can move, and/or the distance of such movement, in response to a temperature change of device 10. For example, device 10 can comprise one or more coils attached along their width (e.g., along axis 60a; FIG. 1). With reference to FIG. 2, this can be achieved by attaching the edge 10A of one coil 50 to the opposite edge 10B of another coil 50.

[0038] In another example, device 10 can comprise a "nested" coil system with one or more coils nested together and extending around axis 60a. This may be referred to as a "coil within coil" configuration. FIG. 1A illustrates an embodiment of device 10 comprising a second coil 50a nested within coil 50 and extending around axis 60a. A nested coil system can be implemented to vary the force with which device 10 can move, and/or the distance of such movement, in response to a temperature change of device 10. For example, in a configuration with nested coils 50 and 50a, device 10 can move with a greater force than a configuration of device 10 with only one of coil 50 or 50a. Coils 50, 50a can contact and/or be attached to each other at one, two, or more points along their lengths (e.g., along the surfaces of or proximate to the inner and outer ends of coils 50, 50a). Coils 50, 50a can be positioned with a gap 21 between each other at one, two, or more points along their lengths. Gap 21 can extend substantially throughout some, most, or substantiality the entire length of coils 50, 50a. Gap 21 can be provided to allow relative movement between the portions of coils 50 and 50a that are not attached to each other, in response to a temperature change of device 10. Additionally, the portions (e.g., surfaces) of coils 50 and 50a between which gap 21 extends can be exposed to environmental conditions, allowing, for example, additional temperature transfer to and from these portions of coils 50 and 50a. Embodiments of device 10 with two or more coils that include a gap between portions of their length can thus respond more quickly to changes in environmental conditions, such as temperature. In some embodiments, device 10 can include three, four, or more nested coils, with an optional intervening gap between each adjacent coil. The coils 50, 50a can be similar to those other embodiments of coil 50 described herein, and any details not shown in FIG. 1A have been removed for clarity.

[0039] The various embodiments of first and second layers 20, 30 described herein can comprise any of many different materials that can be bonded or otherwise secured to each other and jointly form a multi-layer coil-shape, such as plastic, rubber, metal, wood, and the like. Each of first and second layers 20, 30 can comprise more than one material, such as a composite, alloy, or a material coated, mixed or impregnated with a second material. It is even possible for either or both of the layers 20, 30 to be formed of different materials at different portions of the layer's length and/or width. In some embodiments, the layers 20, 30 comprise completely different materials relative to each other. In other embodiments, a particular material may be common to both layers, as long as the layers' coefficients of thermal expansion (or the layers' respective rates of thermal expansion and contraction) are different. For example, the layers 20 and 30 can have different coefficients of thermal expansion if a combination of materials of one layer is different than a combination of materials of the other layer, even if both layers include a common material in their respective combinations. In another example, the layers 20 and 30 can have different coefficients of thermal expansion if one layer comprises a single material and the other layer comprises a combination of materials that includes said single material.

[0040] While cost-reduction benefits may be enhanced when both layers 20 and 30 contain only non-metallic material(s), certain embodiments involve the presence of metal(s) in one or both layers, possibly in combination with non-metallic material(s), as long as there is a non-metallic material in one of the layers. In some embodiments, layer 20 and/or layer 30 comprises some metallic and some non-metallic material(s). In some embodiments, one of layers 20 and 30 includes one or more metallic materials, and the other layer includes one or more non-metallic materials without any metallic material.

[0041] The layers 20, 30 can be thermally, chemically or mechanically treated to provide, or can comprise any material that provides, increased durability, flexibility, moisture absorption or adsorption, chemical resistance, and/or decreased particle emission. The layers 20, 30 can comprise materials of any color, and can comprise substantially transparent, opaque, or translucent materials, or any combination thereof. The layers 20, 30 can be constructed of relatively flexible materials, to allow device 10 to expand and contract (e.g., bend, flex and/or deform) in response to a temperature change, and in some embodiments, with sufficient rigidity to return to the original shape when the temperature returns to its initial value prior to the expansion or contraction. In some embodiments, layer 20, 30 can comprise permanently deformable materials and/or a shape-memory polymer or alloy. In some embodiments, layers 20, 30 can comprise metals or alloys, such as steel (e.g., stainless, structural, and/or heat-treated), copper, brass, bronze, aluminum (e.g., cast or wrought), invar, magnesium, iron (e.g., wrought iron or cast iron), and/or titanium (e.g., titanium alloys). [0042] First layer 20 and second layer 30 can comprise any of many different types of materials, including any of the following exemplary polymers, resins, plastics (e.g., thermoplastics) and/or films: amorphous thermoplastics (for impact and temperature resistance), such as polycarbonates, polystyrenes, acrylonitrile-butadiene-styrenes (ABS), styrene-acrylonitriles, and polyvinyl chloride (PVC); crystalline thermoplastics (for strength, stiffness and impact resistance), such as polyoxymethylene (e.g., POM, polyacetal, or polyformaldehydes), polyamides (e.g., nylons), polypropylene, and polyesters (e.g., polyester imides, unsaturated polyesters); semi-crystalline thermoplastics, such as polyethylene (e.g., acrylonitrile-chlorinated polyethylene-styrene copolymers, chlorinated polyethylenes, high-density polyethylenes, medium-density polyethylenes, linear low-density polyethylenes, polyethylene terephthalates, or ultra-high molecular weight polyethylene) (for lower shrinkage and warping, and increased performance in electrical and mechanical components); glass-based, or glass-filled thermoset phenolic laminates (for a lower coefficient of linear thermal expansion), such as grades G3 (glass cloth/phenolic resin), G5 and/or G9 (glass cloth/melamine resin), G7 (glass cloth/silicon resin), and G10/G11 (glass cloth/epoxy resin); and high temperature plastics, such as New Zenite® liquid crystal polymer (LCP) manufactured by DuPont, Inc., and Aurum® plastics manufactured by Mitsui Chemicals, Inc. Through the use of high temperature plastics, device 10 can be used to replace a bi-metallic strip used in high temperature applications.

[0043] First layer 20 and second layer 30 can comprise any of the following materials that may fall into the aforementioned categories or into different categories: ionomers, isobutylene-maleic anhydride copolymers, acrylonitrile-acrylic styrene copolymers, acrylonitrile- styrene copolymers, ethylene-vinyl chloride copolymers, ethylene-vinyl acetate copolymers, ethylene-vinyl acetate-vinyl chloride graft copolymers, vinylidene chlorides, vinyl chlorides, chlorinated vinyl chlorides, vinyl chloride- vinylidene chloride copolymers, chlorinated polypropylenes, polybutylene terephthalates, high impact polystyrenes, polymethylstyrenes, polyacrylic esters, polymethyl methacrylates, epoxy acrylates, alkyl phenols, rosin-modified phenolics, rosin-modified alkyds, phenolic resin-modified alkyds, epoxy resin-modified alkyds, styrene-modified alkyds, acryl-modified alkyds, amino alkyds, vinyl chloride-vinyl acetate copolymers, styrene-butadiene copolymers, epoxys, polyurethanes, vinyl acetate-based emulsions, styrene-butadiene-based emulsions, acrylic ester-based emulsions, water-soluble alkyds, water-soluble melamines, water-soluble ureas, water-soluble phenolics, water-soluble epoxys, water-soluble polybutadienes, cellulose acetate, cellulose nitrate, ethyl cellulose, polyvinyl alcohols, ethylene-vinyl alcohol copolymers, fluorocarbons, polyimides, polyphenylene oxides, polysulfones, TPX polymers, poly-p-xylenes, polyamideimides, polybenzimidazoles, rubber hydrochlorides, and oblate.

[0044] Particularly effective materials for use within layers 20, 30 include a high pressure processed polyethylene film, a medium-low pressure processed polyethylene film, a crosslinked polyethylene film, an ethylene-vinyl acetate copolymer film, an ethylene- acrylic ester copolymer film, an ionomer film, an ethylene-propylene copolymer film, a polypropylene film, a vinyl chloride-propylene film, a polystyrene film, a polyvinyl chloride film, a polyvinyl chloride film, a polyvinyl alcohol film, a fluorocarbon resin film, a polycarbonate film, an acetyl cellulose film, a polyester film, a polyamide film, a rubber hydrochloride film, a polyimide film, a polyurethane film, an oblate film, a regenerated intestinal film, a polypeptide film, and an amino acid film. Other examples of particularly effective materials for use within layers 20, 30 when formed into coil 50 are described further below, in Examples 1-5.

[0045] Some of the materials described herein, depending on the method of manufacture, must undergo a tempering or annealing process in order to stabilize the plastic, which can provide additional stability to device 10. ABS, for example, can be heated 50° F per hour to 200° F, held at that temperature for 30 minutes per ¼ inch thickness, and cooled down at a rate of 50° F per hour in a nitrogen environment. Glass filled Polycarbonate can be heated to 290° F for 4 hours and then held at that temperature for 30 minutes per ¼ inch thickness, cooled down at a rate of 50° F per hour in an air environment.

[0046] Layers 20, 30 can comprise any of many different materials that provide a particular color and/or sheen to device 10. In some embodiments, layers 20, 30 can comprise one or more transparent films (e.g., multi-layer films comprising, e.g., polypropylene, ethylene-vinyl acetate, polystyrene, polyolefin, and/or acrylic resin, and various combinations thereof) that reflect and/or interfere with certain wavelengths. In some embodiments, layers 20, 30 can comprise a metalized film, such as polyester, unplasticized polyvinyl chloride, acetyl cellulose, polycarbonate, polypropylene, polystyrene, and the like, including a deposit of aluminum, silver, zinc, gold, platinum, etc. Layers 20, 30 can comprise flakes having a metallic luster (e.g., titanium dioxide- coated mica, iron oxide-coated mica, guanine, sericite, basic lead carbonate, acid lead arsenate, bismuth oxychloride, etc.), metallic, glass, and/or seashell powder, etc. In some embodiments, thermochromatic materials can be used, such that layer 20 and/or layer 30 change color in response to a temperature change of device 10.

[0047] In some embodiments, layers 20, 30 can include fabric coverings or sleeves (each covering some or all of the layer 20, 30) (e.g., woven fabric, mesh, lace, etc.) bonded on their outward surfaces. Such fabrics can provide a texture that may be aesthetically pleasing and/or beneficial to the user in certain applications, for example, in toys or medical devices that may directly contact the user.

[0048] Layer 20 and/or 30 can be formed using any of many known extrusion, injection molding, impact molding, spray molding, casting, and other techniques for forming an at least partially non-metallic layer. Layers 20, 30 can be separately formed and then joined (e.g., bonded) together. A bonding step can be used to bond layers 20, 30 at bonding interface 40, using any of a variety or combination of attachment techniques, such as sonic bonding (e.g., ultrasonic bonding), chemical bonding (e.g., covalent bonding), thermal bonding, non-metallic welding, brazing and/or soldering, mechanical bonding (e.g., pressing, pressure-bonding, or mechanical fasteners) or with an adhesive layer (e.g., pressure sensitive adhesive) positioned between layers 20, 30. Sonic bonding in particular has allowed various configurations of non-metallic layers 20, 30 to be bonded and reliably used in some configurations (e.g., a coiled shape) without separation between the layers. In some embodiments, layers 20, 30 can be integrally formed, e.g., through a co-extrusion process or any other process that forms the cross-sectional shape of layers 20, 30 while bonding layers 20, 30 to each other. In some embodiments, one of layers 20, 30 can be initially formed (e.g., with a mold or casting), and the other of layers 20, 30 can be subsequently formed and bonded onto the first of layers 20, 30 (e.g., using the same or a different mold or casting).

[0049] Bonding interface 40 can extend along part, some, or along a substantial entirety of a length of layers 20, 30. For example, bonding interface 40 can be configured to allow one or more gaps to extend between one or more portions of layers 20, 30. Such gap(s) can allow relative movement between some portions of layers 20, 30, and/or can provide additional temperature transfer to and from portions of layers 20, 30, substantially similar to gap 21 positioned between strips 50, 50a, and described further herein (FIG. 1A). [0050] The aforementioned adhesive layer can comprise layers formed of any of a variety of adhesives, including hot melt adhesives, alkyl phenol resins soluble or dispersible in water or organic solvents, rosin-modified phenolics, rosin-modified alkyds, styrene-modified alkyds, acryl-modified alkyds, amino alkyds, vinyl chloride-vinyl acetates, styrene-butadienes, epoxys, acrylic esters, unsaturated polyesters, polyurethanes, vinyl acetate-based emulsions, styrene-butadiene-based emulsions, acrylic ester-based emulsions, water-soluble alkyds, water-soluble melamines, water-soluble ureas, water- soluble phenolics, water-soluble epoxys, water-soluble polybutadienes, cellulose derivatives, polyvinyl alcohols, and other adhesives. It will be understood that when layers 20, 30 are bonded using an adhesive layer, the adhesive layer will comprise a nominal thickness, although bonding interface 40 (FIG. 1) is shown without a substantial thickness, for illustrative purposes.

[0051] It will be understood that while the materials employed for layers 20, 30 may be selected for their coefficients of thermal expansion, layers 20, 30 can comprise materials selected for one or more additional properties suitable for one or more applications in which temperature- sensitive device 10 is employed. For example, one or more of the layers 20, 30 can comprise a material selected with a strength (e.g., compressive, tensile, flexural and/or torsional strength, etc.), hardness or durometer, creep, melting temperature, Poisson's ratio, spring coefficient, frictional coefficient, chemical reactivity (e.g., resistance), water absorptive or resistive qualities, or any of a number of properties suitable for any of a variety of applications for device 10.

[0052] Layers 20, 30 can be bonded with various bonding strengths, depending on the materials selected, the environmental conditions in which device 10 will be used, the shape of device 10, the difference in coefficients of thermal expansion between layers 20, 30, etc. Layers 20, 30 can be bonded with sufficient strength to maintain attachment and prevent delamination of layers 20 and 30 when device 10 is formed into a coiled shape, and when device 10 moves as a result of a temperature change and a difference in rates of thermal expansion or contraction between layer 20 and layer 30.

[0053] The difference in the coefficient of thermal expansion between first layer 20 and second layer 30 can be selected depending on the applications for which device 10 will be used. In some embodiments, the relative difference in the coefficient of thermal expansion between first layer 20 and second layer 30 can range from approximately 3% to approximately 97%, or more narrowly, approximately 5% to approximately 85%, or even more narrowly, from approximately 10% to approximately 65%.

[0054] Referring again to FIGS. 1 and 2, one of layers 20, 30 comprises a higher expansion side (e.g., a material with a higher coefficient of thermal expansion than the other of layers 20, 30) and the other of layers 20, 30 comprises a lower expansion side (e.g., a material with a lower coefficient of thermal expansion than the other of layers 20, 30). In operation, when device 10 is exposed to a higher temperature, the layer with a higher coefficient of thermal expansion will expand more than the layer with the lower coefficient of thermal expansion. The difference in expansion between the layers 20, 30 causes internal stresses to form between the layers, moving (e.g. deforming, bending, or flexing) the device towards the lower expansion side. Conversely, when device 20 is exposed to a lower temperature, the layer with the higher coefficient of thermal expansion will contract more than the layer with the lower coefficient of thermal expansion, moving the device towards the higher expansion side.

[0055] The coil 50 can expand or contract in response to a change in temperature, causing the coil 50 to wind around axis 60a (e.g., by moving in either or both of directions 91 and/or 92) or unwind around axis 60a (e.g., by moving in either or both of directions 93 and/or 94). In some embodiments, layer 20 can have a greater coefficient of thermal expansion than layer 30, causing coil 50 to wind around axis 60a (e.g. move in directions 91 and/or 92) when device 10 is heated, and unwind around axis 60a (e.g., move in directions 93 and/or 94) when device 10 is cooled. In some embodiments, layer 20 can have a lower coefficient of thermal expansion than layer 30, causing coil 50 to unwind around axis 60a (e.g. move in directions 93 and/or 94) when device 10 is heated, and wind around axis 60a (e.g., move in directions 91 and/or 92) when device 10 is cooled.

[0056] Layers 20, 30 can be configured to have many different cross-sectional shapes, such as an approximately square, rectangular, semicircular, or any other cross- sectional shape which can form at least one engagement surface when extended longitudinally, to bond or otherwise be secured to a correspondingly shaped engagement surface on the other of layers 20, 30, and which can form a looped coil 50 around axis 60a, and move when the temperature of device 10 changes. Layers 20, 30 can comprise the same or different cross-sectional shapes relative to each other. In the illustrated embodiment, layer 20 comprises an approximately rectangular cross-sectional shape of width Wi and thickness T _l5 and layer 30 comprises an approximately rectangular cross- sectional shape of width W ₂ and thickness T ₂ .

[0057] Layers 20, 30 can be configured to have many different widths W _l5 W ₂ and thicknesses Ti, T ₂ . In certain embodiments, the width Wi, W ₂ of layers 20, 30, respectively, can range from approximately 0.05 inches to 3 inches, or more narrowly, from approximately 0.1 inches to 2 inches, or even more narrowly, from approximately 0.25 to 1 inches. In certain embodiments, the thickness T _l5 T ₂ of layers 20, 30, respectively, can range from approximately 0.005 inches to 0.5 inches, or more narrowly, from approximately 0.008 inches to 0.2 inches, or even more narrowly, from approximately 0.01 to 0.1 inches. The thickness Ti or T ₂ of layers 20, 30 can be within the range of from approximately 50-300%, or more narrowly, 75-250%, or more narrowly, 80-200% of the other of the thickness Ti or T ₂ of layers 20, 30. The width Wi, W ₂ and/or thickness T _l5 T ₂ can be selected such that layers 20, 30 can form coil 50, which can move in response to temperature changes, as described further herein. Increasing or decreasing the width of layer 20 and/or 30 can increase or decrease, respectively, the force exerted by coil 50 when coil 50 moves in response to a temperature change of device 10. Increasing or decreasing the thickness of layer 20 and/or 30 can increase or decrease, respectively, the force exerted by coil 50, and can decrease or increase, respectively, the amount of movement of coil 50, when coil 50 moves in response to a temperature change of device 10.

[0058] The embodiments described herein for device 10 provide a bi-material coil comprising two non-metallic layers that can be reliably bonded and employed in a variety of temperature applications, including high-temperature applications. In some embodiments, device 10 can be used reliably, without delamination of layers 20, 30, and with movement of coil 50 in response to a temperature change, within and throughout a temperature range, including, e.g., an extreme temperature range, that spans room temperature, such as a range between about -100 degrees Fahrenheit to about 900 degrees Fahrenheit, or between about 32 degrees Fahrenheit to about 212 degrees Fahrenheit, or between about 40 degrees Fahrenheit to about 140 degrees Fahrenheit, or between about 60 degrees Fahrenheit to about 120 degrees Fahrenheit. In some embodiments, device 10 can be used at approximately room temperature. [0059] Device 10 can include one or more structures to allow coil 50 to be employed within (e.g., to be linked to) various devices, such as the aforementioned clocks, dryers, heaters, cooling devices, thermometers, thermostats, switches, valves and other actuators and control systems. Such structures can be attached to, linked to, or surround various portions of coil 50 (e.g., portions of loops 66-69), to allow coil 50 to link a portion of device 10 (e.g., mechanically link) with a device for monitoring or reacting to an environmental condition (e.g., such as the temperature monitoring device shown in FIGS. 5-6 and described further herein).

[0060] FIG. 3 is an expanded side view of an inner portion of temperature- sensitive device 10, indicated by line 3 of FIG. 1. FIG. 4 is an expanded side view of an outer portion of temperature-sensitive device 10, indicated by line 4 of FIG. 1. Referring to FIGS. 1, 3 and 4, in some embodiments, linking members or portions can extend from and/or be attached to (e.g., movably, removably, semi-permanently, and/or permanently attached to) one or more portions (e.g., ends) of coil 50. In some embodiments, an outer member 70 can extend from and/or be attached to a portion of coil 50 proximate to an outer end of coil 50 (e.g., proximate to point 65, or the outer end of loop 69). In some embodiments, an inner member 80 can extend from and/or be attached to a portion of coil 50 proximate to an inner end of coil 50 (e.g., proximate to point 61, or the inner end of loop 66). Member 70 and/or 80 can extend longitudinally or radially from a portion of coil 50 (e.g., relative to axis 60a). Member 70 and/or 80 can extend tangentially, or at any of many different angles from a portion of coil 50 (e.g., from a portion of any of loops 66- 69). In the illustrated embodiment, member 70 extends approximately radially outwardly from the outer end of coil 50, and member 80 extends approximately radially inwardly from the inner end of coil 50.

[0061] Members 70, 80 can comprise any of many different materials and configurations. Members 70, 80 can comprise any of the materials and/or cross-sectional shapes described herein for layers 20, 30, and can comprise the same or different materials and/or cross-sectional shapes as layers 20, 30. Members 70, 80 can be formed separately or integrally with coil 50. For example, members 70, 80 can comprise a portion of coil 50 that is bent to form a linking "tab" proximate to ends 65, 61, respectively, to link coil 50 to a portion of a device. Members 70, 80 can comprise a single layer of material, or can comprise one or more layers of material. Members 70, 80 can comprise the same material or different materials relative to each other. Members 70, 80 can comprise the same cross-sectional shapes or different cross-sectional shapes relative to each other. In the illustrated embodiment, members 70, 80 are formed integrally with layers 20, 30, and comprise the same materials and cross-sectional shapes as layers 20, 30. Members 70, 80 are shown as an approximately rectangular-prism, although it will be understood that member 70 and/or member 80 can include any of many additional structures, such as hooks, loops, tabs, and the like, to link members 70 and 80 with a monitoring device, recording device, control system, etc. Additional and/or alternative features that can be implemented with embodiments of linking member 70 and/or 80 are described below with reference to FIGS. 7A-8B.

[0062] FIG. 5 shows a top-side perspective view of an embodiment of a temperature-recording device 100 in an open position (e.g., for assembly), that can employ an embodiment of the temperature-sensitive device 10 shown in FIGS. 1-4. FIG. 6 shows a top-side perspective view of the temperature-recording device 100 in a closed position (e.g., for operation). In some embodiments, temperature-recording device 100 can be a strip-chart recorder for monitoring, measuring, and recording temperature.

[0063] In the exemplary embodiment, temperature-recording device 100 can comprise a body 110 configured to be linked (e.g., coupled) to at least a portion of the device 10 (e.g., coil 50, possibly with members 70 and/or 80; see also FIGS. 1, 3 and 4). Body 110 can comprise a housing or shell-like structure that substantially encloses device 10 and/or other components therewithin (e.g., a sealable enclosure). In some embodiments, body 110 can include portions with holes, apertures, mesh, caging, or other features that may support and/or protect device 10, including features that do not necessarily enclose device 10. Body 110 can be formed from an integral piece, or from one or more portions configured to engage with each other. In some embodiments, body 110 can comprise a first portion 111 configured to engage with a second portion 112. In some embodiments, body 110 can be movable between an open position (FIG. 5) and a closed position (FIG. 6). Portions 111, 112 can be coupled to each other, and in some embodiments, rotatably coupled, with a coupling device, such as hinge 113.

[0064] Device 100 can comprise a cavity 114 or other structure configured to receive and dispense a strip chart. As it is dispensed, the strip chart is advanced over a surface or platen 115, and wound around a spool 116. An end of the strip chart may be coupled to spool 116 to facilitate the winding. A drive system 117, which can include one or more gears, motors, axles, and the like, powers the rotation of spool 116 during the winding process. Drive system 117 can be powered through batteries, a municipal power supply, solar power, etc. Device 100 can comprise a window 118 extending through the surface of body 110, to facilitate viewing of the strip chart during temperature monitoring.

[0065] Body 110 can comprise any of various linking structures to link one or more portions of device 10 (e.g., a portion of coil 50, such as member 70 and/or member 80) to portions 111 and/or 112. The linking structures can be fixed in one or more dimensions (e.g., linearly and/or rotationally), or can be movable in one or more dimensions, relative to body 110, to allow coil 50 to move in response to a temperature change of device 100. In some embodiments, body 110 can include a linking structure 120 attached to a portion of device 10 (e.g., member 70), and configured to limit or restrict movement (e.g., rotation and/or displacement along any number of coordinate axes, such as x, y, and z axes) of that portion of device 10. In some embodiments, body 110 can comprise a linking structure 130 attached to a portion of device 10 (e.g., a portion of coil 50, such as its center, or member 80 shown in FIG. 3), and configured to convert movement (e.g., rotation and/or displacement) of that portion of device 10 into a detection and/or recordation of the temperature of the device 10. In a preferred embodiment, linking structure 130 is attached to member 80, and allows coil 50 (and member 80) to rotate (e.g., wind and unwind) about an axis at or near a center of the coil 50 (such as axis 60a), preferably without substantially resisting such rotation. In operation, device 10 moves in response to a temperature change of device 100, which in turn causes the linking structure 130 to move (e.g., rotate). It will be understood that various embodiments of linking structures for converting coil movement into a detection and/or recordation of the temperature can be attached to different portions of coil 50, for example, off-set from the center of coil 50, or around the outside of coil 50.

[0066] Device 100 can comprise one or more recording devices that can convert the aforementioned movement of device 10 (e.g., the coil 50 and the linking structure 130) into temperature data, and record the temperature data onto a tangible medium. For example, the device 100 can comprise an electronic device, such as an encoder (e.g., a rotary or linear encoder) that converts the position of coil 50 and/or the linking device 130 into an electronic signal configured to be used by a computer system (one or more computing devices) and/or electronic circuitry to detect, report (e.g., on a hardcopy or on a screen or display of a computer system), or record (on a hardcopy or in a computer-readable storage) the temperature (or other environmental parameter). In some embodiments, device 100 can comprise a member 140 attached to linking structure 130, wherein member 140 moves in response to the aforementioned movement of linking structure 130. Member 140 can be configured to convert the movement and/or position of coil 50 (e.g., a portion thereof, such as ends 61, 65, and/or members 70, 80; FIG. 1) into temperature data and record (e.g., mark) such data onto a tangible medium, such as a strip chart. The strip chart can be pre-marked or otherwise calibrated such that the markings recorded on the strip chart as it moves past member 140, and resulting from the movement of coil 50 and member 140, correspond to measurements of the temperature and temperature changes of device 10.

[0067] FIG. 7A shows an expanded side view of an embodiment of a portion of the temperature- sensitive device 10 comprising the coil 50 of FIG. 1, said portion indicated by line 3 of FIG. 1. FIG. 7B shows an expanded side view of an embodiment of a portion of the temperature-sensitive device 10 of FIG. 1, said portion indicated by line 4 of FIG. 1.

[0068] Referring to FIGS. 7 A and 7B, temperature- sensitive device 10 can include one or more optional linking members 70A and/or 80A. Linking members 70A, 80A can be substantially similar to linking members 70, 80, as described further herein (FIGS. 1, 3-5). For example, linking members 70A, 80A can be configured to link a portion of coil 50 (e.g., a portion proximate to end 61 and/or end 65) to a portion of a device configured to monitor or react to an environmental condition, such as device 100 (FIGS. 5-6). Linking members 70A, 70B can comprise the same or different material, shape and/or size with respect to each other, and/or layers 20, 30.

[0069] Linking members 70A, 80A can optionally be configured to movably (e.g., slidably) engage with respect to coil 50. In some embodiments, such engagement can allow members 70A, 80A to move with respect to each other along coil 50 when engaged with coil 50. For example, temperature- sensitive device 10 can be configured such that member 80A can move between a first and second position with respect to coil 50 (and/or with respect to member 70A). An example of such movement is illustrated in FIG. 7A as movement between "Position A" and "Position B" along a portion of coil 50 (e.g., generally circumferentially) in the directions shown by directional arrows 95 and 96 (FIG. 7A). Additionally or alternatively, temperature- sensitive device 10 can be configured to allow, for example, member 70A to move between a first and second position with respect to coil 50 (and/or with respect to member 80A). An example of such movement is illustrated in FIG. 7B as movement between "Position C" and "Position D" along a portion of coil 50 (e.g., generally circumferentially) in the directions shown by directional arrows 97 and 98 (FIG. 7B). In some embodiments, linking member 80A can be engaged with a portion of coil 50 (e.g., a portion proximate to end 61; FIG. 1, or another portion) that is positioned radially inwardly with respect to a portion of the coil 50 with which linking member 70A can be engaged (e.g., a portion proximate to end 65; FIG. 1, or another portion).

[0070] Movable engagement between coil 50 and one or more linking members 70A, 80A can allow one or more portions of coil 50, linking member 70A, and/or linking member 80A to be positionally adjustable with respect to a portion of a device, such as a portion (e.g., body 110, member 140, etc.) of device 100 (FIGS. 5-6), to allow for adjustment and calibration of device 100. For example, referring to FIGS. 5, 7 A, and 7B, member 70A can be engaged with or attached to linking structure 120, and/or member 80A can engaged with or attached to linking structure 130. The aforementioned movable engagement of linking members 70A, 80A with respect to coil 50, when device 10 implemented in combination with a device, such as device 100, can allow for calibration or adjustment of the measurement span or range of the device 100, high or low endpoints of the measurement range, or center or any other intermediate value of the measurement range. Such movable engagement can allow one or more linking members 70A, 80A to movably engage coil 50 with respect to a portion of device 100 (e.g., body 110, member 40, etc.), to alter a measurement produced by the device 100 for any given change in shape and/or movement of the coil 50.

[0071] The adjustability and movability of linking member 70A and/or 80A with respect to each other and/or coil 50 can reduce the costs of implementing coil 50 within a device. Conventional coiled temperature sensitive devices and the apparatuses within which they are employed are non-adjustable, and cannot be calibrated with respect to each other. Thus, conventional coiled temperature sensitive devices require a high level of precision, for example, with respect to the length, width, thickness, position, number of coils, material composition, or other characteristics of the temperature- sensitive devices, to maintain accuracy of the apparatus in which the devices are employed. The movability of one or more of the linking members 70A, 80A described herein can allow for the aforementioned calibration or adjustment of a temperature recording device 100. Such calibration can reduce the level of precision needed for one or more of the various characteristics of temperature- sensitive device 10 or its components (e.g., coil 50, layer 20, layer 30, ends 61, 65, etc.,).

[0072] The movable engagement described herein between the linking members (e.g., linking members 70A, 80A) and portions of coil 50 can be facilitated in any of a number of different ways. For example, the movability function and the engagement function can be provided by a single, integrally-formed component, or two or more separate components.

[0073] For example, one or more "movable portions" or "movable elements" can facilitate movement between linking members 70A, 80A and/or coil 50, and one or more "engagement portions" or "engagement elements" can facilitate engagement between linking members 70A, 80A and coil 50. The movable elements described herein can comprise one or more of any of a number of devices that can facilitate motion between two or more components, such as slides, actuators, pins, guides, tracks, slots, grooves, bearings, cams, hubs, hinges, ball and pinion, axles, rotational joints, clutches, discs, gears and the like, or combinations thereof. The engagement elements can include any of a variety of corresponding hooks, barbs, clips, tabs, latches, clasps, loops, wires, slots, grooves, guides, cams, pins or other structures and techniques that can provide engagement between two or more components. The movable elements, engagement elements, and/or combined movable engagement elements described herein can be employed within any of the embodiments of device 10 described herein, and for example, can provide movement and/or engagement function to any of linking members 70, 80 (FIGS. 1, 3 and 4), and/or 70A, 80A (FIGS. 7A-8B).

[0074] Referring to FIGS. 7A-7B, temperature- sensitive device 10 can include one or more movable engagement elements 150 configured to movably engage one or more linking members 70A, 80A to a portion of coil 50, and facilitate the aforementioned movement therebetween. Movable engagement element 150 can comprise any of a number of the aforementioned embodiments described generally for movable elements and engagement elements, some examples of which follow:

[0075] FIG. 8A shows a cross-sectional view of an embodiment of the temperature-sensitive device 10 of FIG. 1, taken along line 8-8 of FIG. 7A. FIG. 8B shows a different cross-sectional view of an embodiment of the temperature- sensitive device 10 of FIG. 1, taken along line 8-8 of FIG. 7A. FIGS. 8A and 8B illustrate embodiments of movable engagement elements 150A and 150B, respectively, which can provide the aforementioned movable engagement between one or more components. Although FIGS. 8 A and 8B are shown as a cross-section of linking member 80A shown in FIG. 7 A, it will be understood that embodiments of movable engagement elements 150A and/or 150B described herein can be implemented with other embodiments of device 10 described herein. For example, movable engagement elements 150A and/or 150B can provide movement and/or engagement to linking members 70 and/or 80 (FIGS. 1, 3 and 4) and/or 70A (FIG. 7B).

[0076] Referring to FIGS. 8 A and 8B, movable engagement elements 150A, 150B can include one or more sidewalls, such as sidewalls 151, 152, and/or 153 configured to wrap around some (e.g., FIG. 8A), most, or substantially the entirety of (e.g., FIG. 8B) the cross-sectional perimeter of coil 50 (e.g., layers 20, 30). In some embodiments, sidewalls 151, 152, and/or 153 can be configured to wrap around a sufficient portion of coil 50, to provide movable engagement between the movable engagement elements 150A, 150B and the coil 50.

[0077] In some embodiments, such as that shown in FIG. 8B, engagement elements 150A, 150B can include an optional locking element 156, to selectively restrict and allow movement of movable engagement element 150A, 150B with respect to coil 50. For example, referring to FIGS. 7A-7B and 8B, locking element 156 can be released or unlocked to allow movement of elements 70A, 80A between positions A and B, or any other point along coil 50, and locked to secure, lock, or hold elements 70A, 80A at position A and/or B, or any other point along coil 50. For illustrative purposes only, locking element 156 is shown in FIG. 8B as comprising a handle or tab 157 with a threaded stem portion 158 extending therefrom. Threaded stem portion 158 can be extended through a corresponding hole 154 with corresponding threads 155 extending through sidewall 153 of movable engagement element 150B. However, engagement elements 150A, 150B can include any lock, latch, clamp, press fit, or other movement- restricting structure that is configured to selectively allow and restrict movement of elements 150A, 150B with respect to a portion of coil 50.

[0078] The following tests were done in a controlled testing enclosure using an NIST traceable Hart 850C digital thermometer: EXAMPLE 1

[0079] When an approximately 0.5 inch (12.7 mm) wide strip of 20% Glass- Filled Polycarbonate having a thickness of approximately 0.030 inches (0.762 mm) and an coefficient of thermal expansion of approximately 1.5 in./in./deg F x 10 ^~5 , as stated by the manufacturer, was bonded to an ABS strip of the same width and having a thickness of approximately 0.065 inches (1.651 mm) and a coefficient of thermal expansion of approximately 5.3 in./in./deg F x 10 ^"5 , as stated by the manufacturer. It will be understood that the coefficient of thermal expansion cited by the manufacturers can vary. Similar glass-filled polycarbonate strips have been cited by a manufacturer as having a coefficient of thermal expansion of approximately 1.5 in./in./deg F x 10 ^"5 , and similar ABS strips have been cited by a manufacturer as having a a coefficient of thermal expansion of approximately 4.0 in./in./deg F x 10 ^"5 . The two strips were bonded using Weld On ^® 3 adhesive manufactured by IPS Corporation, located in Compton, CA, to form a coil that was approximately 12 inches long, approximately 0.5 inches wide, and included approximately 3.5 loops. The resulting coil, operating at a temperature range between approximately -5 degrees to 95 degrees Fahrenheit, had a similar force and movement of a Bi-metal coil having a thickness of approximately 0.032 inch (.762 mm) and a width of approximately 0.5 inch (12.7 mm).

EXAMPLE 2

[0080] When an approximately 0.5 inch (12.7 mm) wide strip of 20% Glass Filled ABS having a thickness of approximately 0.030 inch (0.762 mm) and a coefficient of thermal expansion of approximately 1.7 in./in./deg F x 10-5 was bonded to a non-filled ABS strip of the same width and having a thickness of approximately 0.060 inch and a coefficient of thermal expansion of approximately 5.3 in./in./deg F x 10 ^"5 ; the resulting coil had similar force and movement of a Bi-metal coil having a thickness of approximately 0.032 inch (.762 mm) and a width of approximately 0.5 inch (12.7 mm). The temperature range, bonding method, number of loops, and length of the coil used in this test were similar to those described herein for EXAMPLE 1.

EXAMPLE 3

[0081] When using an approximately 0.5 inch (12.7 mm) wide strip of 20% Glass Filled Acetal having a thickness of approximately 0.035 inch (0.889 mm) and a coefficient of thermal expansion of approximately 2.2 in./in./deg F x 10 ^"5 was bonded to a non filled Acetal strip of the same width and having a thickness of approximately 0.080 (2.032 mm) and a coefficient of thermal expansion of approximately 8.5 in./in./deg F x 10 ^"5 ; the resulting coil had a similar force and movement as a Bi-metal coil having a thickness of approximately 0.032 (.762 mm) and a width of approximately 0.5 inch (12.7 mm). The temperature range, bonding method, number of loops, and length of the coil used in this test were similar to those described herein for EXAMPLE 1.

EXAMPLE 4

[0082] When an approximately 0.5 inch (12.7 mm) wide strip of LDPE having a thickness of approximately 0.080 inch (2.032 mm) and a coefficient of thermal expansion of approximately 3.0 in./in./deg F x 10 ^"5 was bonded to a strip 20% Glass Filled Polycarbonate of the same width and having a thickness of approximately 0.035 inch (.889 mm) and a coefficient of thermal expansion of approximately 1.5 in./in./deg F x 10 ^"5 ; the resulting coil had a similar force and movement as a Bi-metal coil having a thickness of approximately 0.032 inch (.762 mm) and a width of approximately 0.5 inch (12.7 mm). The temperature range, bonding method, number of loops, and length of the coil used in this test were similar to those described herein for EXAMPLE 1.

EXAMPLE 5

[0083] When an approximately 0.5 inch (12.7 mm) wide strip of ABS having a thickness of approximately 0.090 inch (2.286 mm) and a coefficient of thermal expansion of approximately 5.3 in./in./deg F x 10 ^"5 was bonded to Phenolic G10 of the same width and having a thickness of approximately 0.031 inch (.7874 mm) and a coefficient of thermal expansion of approximately 0.55 in./in./deg F x 10 ^"5 ; the resulting coil had a similar force and movement as a Bi-metal coil having a thickness of approximately 0.032 inch (.762 mm) and a width of approximately 0.5 inch (12.7 mm). The temperature range, bonding method, number of loops, and length of the coil used in this test were similar to those described herein for EXAMPLE 1.

[0084] Although certain preferred embodiments and examples have been discussed herein, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. In addition, while a number of variations of the invention have been shown and described in detail, other modifications, which are within the scope of this invention, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the invention. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed invention. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the present disclosure, including the appended claims.