MOTOR OIL FORTIFIER
Field Of The Invention [001 ] The present invention relates to a lubricant treatment for use as a motor oil lubricant additive and the like. More specifically, the present invention relates to a method and composition of improving the performance of a lubricant to enhance the life and performance of an engine or other lubricated system.
Background Of The Invention [002] Conventional motor oils, including synthetic oils, have been known for quite some time to improve the life and performance of engines for cars, tracks, tractors and other machines that use engines, such as construction equipment, lawnmowers, etc. Also known for quite some time is that certain added materials may enhance or improve the performance of these motor oils to further improve and extend the performance of the oil, and thus to extend the life and performance of the engine.
[003] Marketers have coined the phrase "treatments" for such products marketed to improve or enhance the performance of engine oils. These treatments help to lubricate the moving parts of the engine and thus reduce the wear. These treatments may last for a short or longer period of time depending on the formulation. Various treatments may have varying levels of efficacy and may improve the life and performance of the treated engine in varying degrees. These treatments may also be referred to as an oil fortifier or engine treatment. The treatment may also be used as an additive to lubricants such as hydraulic lubricants, gear lubricants, compressor lubricants, or diesel oil lubricants. [004] Previously, friction reducing agents and other lubricants were often comprised of lead based materials. Though lead based lubricants are particularly effective, lead based materials have been known to cause health and environmental hazards. An alternative to utilizing lead or lead based materials in lubricants is therefore required.
[005] In an engine, friction may occur as a result of pressure, low speed, high temperatures or reduced viscosity. All of these conditions may cause the lubricating film, which normally separates moving parts, to become so thin that metal-to-metal contact occurs. Conventionally employed additives to combat this contact may utilize phosphorous, chlorine, zinc, or sulfur containing compounds to reduce friction and to prevent destructive contact between the metal surfaces. [006] One such alternative treatment additive, shown in U.S. Pat. No. 4,888,122, Engine Oil Additive Dry Lubricant Powder, provides an additive that forms a sub- micron layer coating on the bearing surfaces of an engine. A mixture of two types of polytetrafluoroethylene (PTFE) and about 1-2% TiO2 are added to the engine oil. The titanium dioxide burnishes the surfaces and enhances the adhesion of the PTFE. The PTFE can be viewed as a sacrificial surface that slowly wears off of the coated engine part, thus preventing the wear of the part itself. [007] Extreme pressure agents have also been known to improve wear characteristics, but limitations such as solubility, acidity and cost have previously prevented these materials from being successfully utilized as a motor oil additive. Therefore, a need exists for a motor oil additive that solves one or more of the shortcomings of the present available additives.
Brief Summary Of The Invention
[008] One embodiment of the present invention includes a lubricating composition, comprising a base fluid and a bismuth in a non-active sulfur carrier.
[009] Another embodiment of the present invention includes lubricant additive formulation comprising the following composition in volume percentage 33-65% base fluid selected from the group consisting of synthetic oil, naphthenic oil, polybutene, and a combination of naphthenic oil and polybutene and 5-50% bismuth component in a carrier.
[010] Yet another treatment for addition to a lubricant includes an oil of a base fluid and a bismuth.
[011 ] Still another lubricant composition includes a base fluid, a bismuth component, a detergent and a dispersant.
[012] Another embodiment of the present invention includes a hydraulic fluid treatment comprising a base fluid, a bismuth component in a non-active sulfur carrier and a dispersant.
[013] Still another embodiment includes a gear oil treatment comprising a base fluid a bismuth component in a non-active sulfur carrier.
Detailed Description
[014] The present invention pertains to compositions and methods of unique additives useful in motor oils to increase the oil's lubricating and wear resistant properties. The composition of the present invention is added to various viscosities of lubricant for use in cars, trucks, tractors, and other small or large engines. Whether the engine requires a low, high or multi-weight oil, the present invention can be utilized as an additive to increase the wear resistance of the oil so that the life of the treated engine can be extended.
[015] The present invention can also be modified slightly for use as a lubricant treatment in other systems. For example, the present invention may be useful as a hydraulic treatment, a gear treatment, a compressor treatment, or a diesel engine treatment. The basic formula can be modified to better perform in each of these specific instances. A few example modifications to the formula for use in such applications are further described herein. The preferred embodiment will be described as a motor oil fortifier with other examples given for other systems that require lubrication. [016] As used herein, the term "motor oil additive," "additive," or "lubricant additive" is used to mean a material, formulation, composition, etc. that can be added to a motor oil for enhancement of the oil's lubrication, wear resistance, and physical properties. The term additive may not be universally utilized to describe such products; other terms can be used by those skilled in the art such as treatment, enhancer, fortifier, engine oil fortifier, etcetera.
[017] It has been discovered that utilizing bismuth in a base fluid results in a lubricant that noticeably improves the wear characteristics of a stock motor oil when added to the same. The bismuth component has much the same properties as lead, being soft and malleable at relatively low temperatures. Bismuth is also easily deposited on the surfaces to be protected. However, the bismuth component advantageously has much more desirable characteristics when it comes to pollution.
[018] In one embodiment, the bismuth component is present in a non-active sulfur carrier utilized to deliver, i.e. solubilize, the bismuth in solution. In alternative embodiments, the base fluid may be comprised of group III base fluid, polyalphaolefin, polybutene, severely hydrotreated naphthenic base fluid, or combinations thereof. Other materials that can also be included in the present invention to further enhance physical properties, such as lubricity and wear resistance, can include one or more of the following: a defoamer, a detergent, or a dispersant. In alternative embodiments, some, all, or none of these materials can be present in the present inventive additive. While each of these components may have been previously known as additives to lubricants, or as treatments, the present combination represents a novel composition and method for use. [019] Each of these materials will now be described in turn and then the method of mixing and using it will be described.
[020] The present invention resides in a novel and improved liquid lubricant additive formulation which includes the following components (percentage by volume):
Group HI base fluid 58.9% Bismuth in a non-active sulfur (bismuth phosphate ester and a non- active sulfur combination) 30%
Dispersant 5%
Detergent 6%
Defoamer .1% [021 ] Some of the above components can be added to the present invention to endow it with additional lubrication enhancement properties without changing the
nature and scope of the present invention. In alternative embodiments the amount of each component may be varied by those skilled in the art to enhance certain characteristics.
[022] Each of these components and the properties of each as utilized by the present invention will now be herein described. In still further embodiments amounts of the above ingredients can be varied without changing the nature and scope of the present invention. In still further embodiments, some or all of these additional materials can be excluded or added in varying amounts.
Base fluid
[023] The present embodiment of the present invention utilizes a base fluid that is a group m base fluid. Group m fluids are known to those skilled in the art to have particularly good solubility and lubricity characteristics and qualify as a synthetic in base stock classifications. In the present embodiment, group III fluid may represent approximately 58.9% by volume of the total volume of the present invention additive. One problem often faced in creating oil additives such as the present invention has been dissolution of all of the components into solution and having them remain in solution. Advantageously, group III fluids have been found to be particularly useful at helping to solve this solubility problem. For example, group HI fluids have a viscosity of approximately 5.28 centistokes at 40°
C and viscosity index of approximately 100.
[024] One commercially available group HI fluid that is useful in the present embodiment formulation is Petro-Canada High Viscosity Index Improver Synthetic Base fluid, NHNI-2. This material is available from Petro-Canada, 385 Southdown Road, Mississauga, Ontario Canada L5J 2 Y3. Some of the particularly useful qualities of this oil, in addition to the various qualities of a group HI fluid, include superior low temperature properties at a lower cost. [025] In an alternative embodiment, the base fluid can be a polybutene or a combination of polybutene and a second oil, such as group IH fluid or a severely hydrotreated naphthenic oil (which can be utilized as a base fluid in another
embodiment of the present invention). Polybutene, also known as polybutylene, is a thermoplastic polymer of isobutene of varying molecular weight and is known for use as an additive to lubricants. Polybutene may provide excellent shear stability as well as good thermal and oxidative stability. Polybutene has a high flash point and is known to exhibit excellent extreme pressure properties. This material, however, is more expensive than naphthenic oil, or other alternative oils, and is not as preferred as other oils on a purely cost basis. n further alternative embodiments, the base fluid can also be comprised of polybutene or a polyalphaolefin. In still further embodiments a PAO known to those in the art may also be utilized.
[026] hi still further embodiments the base fluid can be approximately 25-60% of the total composition by volume. In still further embodiments, the base fluid may represent 25-35% of the total composition by volume, 45-60% of the total composition by volume, or 35-45% of the total composition by volume. Typical examples of synthetic base fluids are long chain alkylbenzenes, branched alkylbenzenes, polyolefins such as alkylnaphthalenes, ester oils, and polyglycols.
Bismuth [027] In the present invention, the selected bismuth component can represent approximately 30% by volume of the present embodiment formulation. It has been discovered that bismuth is particularly useful as a sacrificial film material because it is soft at high temperatures and is not as hazardous as many of the prior art oil additive materials. Bismuth in a non-active sulfur carrier is utilized in the present embodiment because of the high solubility of the bismuth material in the non-active sulfur material and bismuth's usefulness in arriving at the surfaces to be lubricated, i.e. the bismuth in a non-active sulfur carrier has been found to be very effective at creating the proper type of sacrificial layer. As may be appreciated by those skilled in the art, other bismuth containing materials may be utilized as delivery vehicles for placing the bismuth on the desired surfaces.
[028] One commercially available bismuth containing material that can be utilized is Liovac 3043, an organometallic bismuth in a non-active sulfur carrier that is approximately 16-17% bismuth and 6.5%-7% inactive sulfur. This material is produced by Miracema-Nuodex, Indistria Quimica, Ltd. Liovac 3043 shows excellent solubility in group IH base fluid. The Liovac 3043 can include about 60% or more of bismuth carboxylate, about 20% or more of sulfur compound, and about 10% or more of phosphate ester. Another preferable bismuth material can contain 50% or more bismuth carboxylate, 10% or more sulfur compound, and 5% or more phosphate ester. In still other embodiments, the bismuth containing material may comprise 5 to 50% by volume, or more, of the bismuth composition. In another embodiment the bismuth material may represent 5-20% by volume of the formulation, 35-50% by volume of the formulation, or 25-35% by volume of the formulation. [029] Other products made by this same company, such as Liovac® 3016, can also be utilized in the present invention. Liovac 3016 is a bismuth naphthenate that is approximately 15% by weight bismuth and which has a viscosity of 100- 200 centistokes at 40° C.
Dispersant [030] The embodiment of the present invention formulation can further include a dispersant to increase cold and hot temperature performance. The dispersant of the present invention may be added in approximately 5% by volume of solution.
[031 ] The dispersant can be added to compositions of the invention to improve both the hot and cold temperature performance of the additive material. In addition to helping the hot and cold temperature multifunctionality, the dispersant aids in the removal of undesirable contaminant materials in the base fluid. The dispersant helps in the removal of undesirable contaminants by helping to hold the contaminants in suspension longer than in the pure base fluid. In this manner, the contaminants can be filtered out by the oil filter before depositing, or re- depositing, on an engine surface.
[032] A preferred dispersant is a polyakenyl succinic anhydride based ashless dispersant in solvent mineral oil. The dispersant generally comprises approximately 5% of the present invention formulation, but can range from approximately 2-8% by volume. In alternative formulations, this material may comprise approximately 5-8% by volume of the formulation or up to approximately 4% by volume. A commercially available dispersant that is suitable for use in the present invention formulation can be Infineum C9231. Infineum C9231 is available from Infineum USA L.P., 1900 East Linden Avenue, P.O. Box 717, Linden, NJ 07036.
Detergent [033] The composition invention can also include a detergent. Detergents often work side by side with a dispersant to keep deposits from forming on the surfaces that are being lubricated. Detergents also help to loosen the carbon deposits that have formed on the engine surface. It is further believed that the detergent can keep the crosshatching of the bore well lubricated by keeping contaminants from forming on the same.
[034] The present inventive composition can, for example, utilize a calcium sulfonate detergent added at approximately 6% by volume. In alternative embodiments, the detergent can comprise approximately 4 to 8% by volume of the present inventive composition. In still further embodiments the formulation may represent up to 5% of the present inventive composition or 6-8% of the present inventive composition. [035] One commercially available detergent useful in the present invention can be purchased under the name Lubrizol 78W, available from The Lubrizol
Corporation, 29400 Lakeland Boulevard, Wickliffe, OH 44092. The 78W material is a highly basic (approximately 400 TBN) calcium sulfonate detergent additive that includes 15-26% calcium by weight and 1.25-1.80% sulfur by weight. The 78W material has a viscosity of 60 centistokes at 100°C. In addition
to the detergent materials listed above, the 78W material is particularly useful for neutralizing acids in both gasoline and diesel engines. [036] Other detergents known to those skilled in the art can be used in the formulations of the invention without changing the nature and scope of the present invention.
Defoamer [037] The present invention can further include a defoamer. When water gets in motor oil, the motor oil may have a tendency to aerate and bubble. Bubbling in the motor oil may break the consistency of the motor oil film on the surfaces to be lubricated, allowing for intermittent metal-to-metal contact. A stock motor oil may already contain a defoamer in the formulation. The addition of a defoamer to the present embodiment, however, can enhance the effectiveness of the already present defoamer. The defoamer included in present invention can comprise approximately 0.1 % by volume, though can be included up to approximately
1.5% by volume.
[038] One defoamer that is useful in the present formulation is Foam Ban 130B. Foam Ban 130B is available from Ultra Additives, Inc., 460 Straight St., Paterson, NJ 07501. This defoamer is an easily blended silicone based material that is specifically formulated for use in industrial lubricants in particular. The viscosity of this material at 25°C is approximately 10 to 24 cps. As may be appreciated by those skilled in the art, other defoamers can be utilized without changing the nature and scope of the present invention. The defoamer can be present in the present invention formulation up to approximately 1.5% by volume. [039] Other materials can also be added to the present invention formulation to increase the effectiveness thereof. For example, in one alternative embodiment, an anti-oxidant can be added, such as Lubrizol 1375 available from The Lubrizol Corporation, 29400 Lakeland Boulevard, Wickliffe, Ohio 44092-2298. Other materials for the alternative embodiment engine oil treatments, and other lubricant system treatments, are discussed below.
Method of Mixing [040] A formulation of the present invention can be synthesized with percentages approximately as follows:
6% Detergent, trade name 78W
5% Dispersant, trade name Infineum C9231
30% Bismuth in a non-active sulfur, trade name Liovac 3043
58.9% Group HI base fluid.
.1% Defoamer
[041] First, the base fluid is added to a covered kettle or other mixing container equipped with a heating element, such as a steam jacketed liner. The bismuth component is added to the base fluid with mixing. The dispersant is then added to the mixture and heated to approximately 95 to 105° F. The rest of the ingredients are then added. Once all of the ingredients are added, heating is continued and the mixture is stirred for as little as 30 minutes, but preferably up to approximately 6 to 8 hours, before decanting into a storage container.
Method of Use [042] The present invention describes materials that may be added to a stock motor oil in order to improve the lubrication performance of the motor oil and to extend the life of the engine. Preferably, this material should be added in greater volume percentages when utilizing the material with an engine the first use.
During subsequent uses, the material can be used in a reduced amount. In a preferred method of use, the present invention is added at approximately 2-10% ratio with the motor oil during the first application. In such an embodiment the motor oil additive of the present invention may be added up to a 5% ratio thereafter, more preferably at approximately a 3% ratio thereafter. This preferred embodiment equates to 1.5 ounces per quart of motor oil during the first use and 1 ounce per quart of the motor oil during subsequent uses.
Example 1
[043] A motor oil additive was prepared utilizing the above formulation with the group HI base fluid in addition to the other components. The material was prepared in the above-described method and mixed for approximately one hour before being decanted into the container. The material was tested utilizing ASTM D-4172B 4-Ball Wear (40 kg, 1200 rpm, 1 hour, 75°C) and ASTM D-2783 Load Wear Index. The 4-Ball Wear test, produced results with a minimum of .56 mm wear scar. The Load Wear Index test results were 63 kg (.36 mm) last non- seizure load (scar), a 620 kg (1.75 mm) last seizure load (scar) and an 800 kg weld load.
Example 2
[044] A motor oil additive was prepared using the following ingredients:
Group HE base fluid 58%
Bismuth in a non-active sulfur 30% Dispersant 5%
Polyol ester 1%
Calcium sulfonate detergent 4.4%
Friction modifier 1.5%
Defoamer 0.1%
[045] Most of these ingredients and their uses in the present invention formulation are described above. The present alternative embodiment further utilizes, however, a polyol ester and a friction modifier.
Polyol Ester [046] The present invention formulation can further include a polyol ester. A polyol ester can be particularly suited for use in the lubricant formulation of the present invention because of its high thermal stability, solubility enhancement properties (enhancing the solubility effectiveness of the chosen base fluid), and oxidative stability. WO 96/28525 to Schlosberg et al. (Schlosberg) discloses the use of polyol esters to improve thermal and oxidative stability, lowers friction coefficients and improves wear in crankcase lubricating
applications. This reference is incorporated herein by reference for all it teaches and discloses.
[047] A preferred polyol ester is octadecenoic acid (Z)-,2-2-bis [[(l-oxo-9- octadecnyl)oxy]methyl]-l,3-propanediyl ester, CAS #19321-40-5. For example, the polyol ester can comprise up to approximately 1% of the present embodiment formulation and is stable up to temperatures as high as 1200°C. hi still further embodiments, the polyol ester may comprise up to 5% of the present inventive composition. [048] A preferred polyol ester is Doverlube FL-219. Doverlube FL-219 is available from Dover Chemical Corporation, 3676 Davis Road N.W., Dover, OH
44622. Doverlube FL-219 may be emulsified to provide lubricity in soluble oils and may itself enhance the lubricity of the present embodiment material. Doverlube 219 is primarily comprised of the above polyol ester. [049] Other suitable polyol esters include esters or diesters and, for example, include the esters of pentaerythritol, polypentaerythritols such as di- and tripentaerythritol, trimethylol alkanes such as trimethylol ethane and trimethylol propane, and neopentyl glycol. Such esters may be formed with linear and/or branched aliphatic carboxylic acids, such as linear and/or branched alkanoic acids, or esterifiable derivatives thereof. A minor proportion of an aliphatic polycarboxylic acid, e.g. an aliphatic dicarboxylic acid, or an esterifiable derivative thereof can also be used in the synthesis of the ester lubricant in order to increase the viscosity thereof.
Friction Modifier [050] The additive of the present invention can further include a friction modifier as an antiwear agent. Friction modifiers are known by those skilled in the art to improve boundary lubrication with antiwear additives or extreme pressure agents. A friction modifier helps those areas of the engine in which two surfaces barely touch, but which can barely touch on a continuous basis. The friction modifier acts as a wetting agent on the contact points to improve lubricity. In some instances, the friction modifier may actually improve the gas mileage of a
car instead of just restoring the gas mileage to the level when the car was new or nearly new.
[051 ] One type of a friction modifier that has been found to lower the friction coefficient of the rubbing parts is a fatty ester. Even a slight reduction of this friction coefficient proves extremely beneficial in the wear rate and efficiency of the engine. One commercially available fatty ester is TFA 4727 available from Texaco as Texaco 4727. In various embodiments this or other friction modifiers, chosen by those reasonably skilled in the art, can comprise up to 5% of the present invention formulation. [052] Other friction modifiers known to those skilled in the art can be useful in the present invention without changing the nature and scope thereof. Such friction modifiers can include: fatty phosphates, fatty acid amides, fatty epoxides, borated fatty epoxides, fatty amines, as well as other materials known to those in the art and mixtures thereof. Still further friction modifiers can also include metal salts of fatty acids.
[053] The material was mixed as in Example 1 and added to an engine lubricant in the same manner. Increased friction reduction capabilities were produced. The material was tested utilizing a ball rust test and utilizing an ASTM D-6335 Thermo-Oxidation Engine Oil Simulation Test. The ball rust test reported an average gray value of 119 and the ASTM D-6335 test produced a total deposits of
36.5 mg.
Example 3 - Hydraulic Treatment
[054] A hydraulic treatment for addition to industrial hydraulic systems was mixed using the following formulation:
54.5% High NHVI-S Synthetic Base fluid 30% Liovac 3043
12% Commercial anti-wear package 2.5% Dispersant 0.8% Rust and oxidation Inhibitor
0.10% Biocide 0.10% Antifoam
[055] Most of these ingredients and their uses in the present invention formulation are described above. The present alternative embodiment further utilizes, however, an anti-wear package, a rust and oxidation inhibitor, and a biocide. [056] The 12% anti-wear package is an additive that provides thermal stability, antiwear protection, and oxidative stability. One such commercially available product useful as an antiwear package additive is Lubrizol 5186 Anti-Wear Package. [057] A rust and oxidation inhibitor can also be added. A rust and oxidation inhibitor provides rust and oxidation control and improves filterability. One commercially available material useful in the present example is Ida-Soil 498, from Ideas Inc., 625 S. Main St., Lombard, 1L 60148. This material provides extended oxidation life, anti-corrosion, water tolerance, and a resistance to sludge formation. [058] A biocide may also be added to the present formulation. A biocide will inhibit the growth of fungus and bacteria in the hydraulic system, tremendously extending the longevity of the hydraulic lubricant to which the present invention is added. One commercially available biocide that is particularly useful in the present formulation is BioBan P-1487® Biocide available from Dow. BioBan P- 1487 has a broad spectrum of activity and is soluble in oil and some synthetic fluids.
[059] Also useful in the present formulation is a defoamer and a dispersant. The useful properties of defoamers and dispersants in a lubricant additive have been previously described. One commercially available defoamer that is useful in the present hydraulic treatment is FoamKnocker M-433 Anti-Foam available from
Ideas, Inc. A commercially available dispersant that is useful with the present hydraulic treatment formulation is Lubrizol 936. Lubrizol 936 can significantly improve lubricant dispersancy properties for engines operating under low and high temperature conditions.
[060] A hydraulic treatment additive is mixed utilizing 30% Liovac 3043, 12% Lubrizol 5186 Anti-Wear Package, 2.5% Lubrizol 936 Dispersant, 0.8% Ida-Sol 498 Rust and Oxidation Inhibitor, 0.10% BioBan 1487 Biocide, 0.10% M 433 Antifoam, 54.5% High VHVI-S Synthetic Base Fluid. The formulation is blended by adding the bismuth material to the base fluid and mixing thoroughly. Once a homogenous mixture is achieved, the other materials are added one by one and mixed, each time checking to make sure that a homogenous mixture is achieved. [061] The material can be added to hydraulic fluid up to approximately 10%, more preferably 4-8%, and more preferably up to 5%.
Example 4 - Gear Treatment
[062] A gear treatment was mixed using the following formulation:
39.9% High VHVI-2 Synthetic Base fluid 30% Liovac 3043 Extreme Pressure and Anti-Wear 15% Commercial lubricant additive
13% Commercial gear oil additive 2% Antiwear and antioxidant .1% Anti-Foam [063] The synthetic base fluid and the bismuth in the non-active sulfur are described above. The present alternative embodiment further utilizes, however, a commercial gear oil additive and an antiwear and antioxidant in addition to an antifoam agent. [064] The gear oil additive may be a pre-formulated package that provides certain advantageous properties. A gear oil additive useful in the present invention is Lubrizol 6043U. Lubrizol 6043U is a multipurpose additive for industrial gear oils that provides outstanding thermal stability, corrosion protective, and seal compatibility. [065] The commercial lubricant additive may include extreme pressure and anti- wear additives to improve the additive's effectiveness under severe friction conditions. Such additives are often available in a commercially available formulation. Various materials may be selected by those skilled in the art, but one
commercially available product that is useful in the present gear additive is Doverlube NCL-2 available from Dover Chemical Corporation. This material is a non-corrosive and non-halogenated pressure lubricant that can be used to replace chlorinated paraffin. [066] An antiwear and antioxidant package can also provide further useful properties to the present formulation. A dithiocarbamate has been found to be such a useful antioxidant. One commercially available dithiocarbamate that is useful in the present gear additive formulation is NA-Lube® ADTC, available from King Industries, Science Road, Norwalk, CT 06852. The NA-Lube material is an extreme pressure, antiwear and antioxidant additive for use in lead-free extreme pressure formulations. The material is very soluble. [067] Finally, an antifoam additive is also useful in the present formulation for a gear lubricant additive. One commercially available additive useful for the present invention is M-433 Anti-Foam. [068] A gear treatment additive is mixed utilizing 34.9% High VHVI-2
Synthetic Base fluid, 15% Doverluebe NCL-2, 13% Lubrizol 6043U, 30% Liovac 3043 Extreme Pressure and Anti-Wear, 2% NA-Lube ADTC Anti-Wear Package, .1% M-433 Anti-Foam. The additive is mixed substantially as above. The material is added to gear lubricants at up to 10% by volume, more preferably 3- 8% and more preferably 5% by volume.
[069] Although the present invention has been described with reference to preferred embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.
[070] While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description. As will be apparent, the invention is capable of modifications in various obvious aspects, all without departing from
the spirit and scope of the present invention. Accordingly, the detailed description are to be regarded as illustrative in nature and not restrictive.