A detergent composition having a plasma-induced, water-soluble coating for controlling solubility, chemical stability and physical properties is disclosed. A process for making such a detergent composition is also disclosed which involves subjecting a detergent material to a plasma glow zone in which an organic hydrophilic monomer is introduced such that it ultimately deposits on the detergent material to form a water-soluble coating. The detergent compositions are particulate or non-particulate and can be used for laundry, dishwashing or other similar application.

The present invention generally relates to detergent compositions, and more particularly, to detergent compositions which have a plasma-induced, water-soluble coating. The detergent compositions may be used in laundry, dishwashing, carwashing, hard surface cleaning or other similar applications. The plasma-induced, water-soluble coating controls the solubility, dispersion, flowability and chemical stability of the detergent composition. The invention also provides a process for making such detergent compositions.
Currently, detergent formulators are faced with numerous problems which impede delivering the active ingredients to the fabric or dishware to be cleaned. By way of example, recent low dosage or xe2x80x9ccompactxe2x80x9d detergent products experience dissolution problems, especially in cold temperature laundering solutions (i.e., less than about 30xc2x0 C.). More specifically, poor dissolution results in the formation of xe2x80x9cclumpsxe2x80x9d which appear as solid white masses remaining in the washing machine or on the laundered clothes after conventional washing cycles. These xe2x80x9cclumpsxe2x80x9d are especially prevalent under cold temperature washing conditions and/or when the order of addition to the washing machine is laundry detergent first, clothes second and water last (commonly known as the xe2x80x9cReverse Order Of Additionxe2x80x9d or xe2x80x9cROOAxe2x80x9d). Similarly, this clumping phenomenon can contribute to the incomplete dispensing of detergent in washing machines equipped with dispenser drawers or in other dispensing devices, such as a granulette. In this case, the undesired result is undissolved detergent residue in the dispensing device.
Another similar problem with detergent compositions, especially granular laundry and dishwashing detergents, is the degradation of physical properties over extended storage periods. More particularly, spray dried granules and other particulate detergent ingredients have a tendency to xe2x80x9ccakexe2x80x9d while stored in the detergent box, especially under highly humid conditions. Such xe2x80x9ccakingxe2x80x9d is very unacceptable to consumers and can lead to difficulties in xe2x80x9cscoopingxe2x80x9d or otherwise removing the detergent from the box in which it is contained. This problem can also result in improper dosing of the laundering solution resulting in decreased cleaning performance. Other problems include chemical instability of the detergent composition and difficulty in dispersing polymers into wash solutions. Heretofore, detergent formulators have unsuccessfully attempted to resolve or minimize all of the aforementioned problems, and they continue to search for convenient solutions which do not affect other properties of the detergent composition.
Accordingly, despite the above disclosures in the art, there is a need for detergent compositions which have improved physical properties, solubility and/or chemical stability. There is also a need for a process for producing such detergent compositions.
The invention meets the above-identified needs by providing a detergent composition having a plasma-induced, water-soluble coating for controlling solubility, chemical stability and physical properties. The invention also provides a process for making such a detergent composition involving subjecting a detergent material to a plasma glow zone in which an organic hydrophilic monomer is introduced such that it ultimately deposits on the detergent material to form a water soluble coating. The detergent compositions are particulate or non-particulate (e.g., tablet) and can be used for laundry, dishwashing or other similar application.
In accordance with one aspect of the invention, a detergent composition is provided. The detergent composition comprises particulate material containing a detergent ingredient selected from the group consisting of detersive surfactants, builders and mixtures thereof; wherein at least a portion of the particulate material has a plasma-induced, water-soluble coating. In accordance with another aspect of the invention, the detergent composition comprises a non-particulate material containing a detergent ingredient selected from the group consisting of detersive surfactants, builders and mixtures thereof; wherein at least a portion of the non-particulate material has a plasma-induced, water-soluble coating.
In accordance with yet another aspect of the invention, a process for producing a detergent composition is provided. The process comprises the steps of: (a) providing a detergent material containing a detergent ingredient selected from the group consisting of detersive surfactants, builders and mixtures thereof; (b) subjecting the detergent material to plasma glow zone in which a gas is ionized and an organic hydrophilic monomer is introduced such that the organic hydrophilic monomer deposits on the detergent material to form a water-soluble coating. As used herein, the xe2x80x9cplasma glow zonexe2x80x9d is the space or region where plasma is generated using electricity, such as the space between two electrodes in a plasma vacuum chamber.
All percentages, ratios and proportions used herein are by weight, unless otherwise indicated. All documents including patents and publications cited herein are incorporated herein by reference.
Accordingly, it is an advantage of the invention to provide a detergent composition which has improved physical properties, solubility and/or chemical stability. It is also an advantage of the invention to provide a process for producing such detergent compositions in an convenient manner. These and other advantages and features of the present invention will become apparent to those skilled in the art from a reading of the following detailed description of the preferred embodiments and the appended claims.
In essence, the invention is directed to particulate and non-particulate detergent compositions having a plasma-induced, water-soluble coating. In preferred modes of the invention, the particulate material is selected from spray dried granules, agglomerates and mixtures thereof, and is applied in the laundry, dishwashing or similar context. The non-particulate detergent compositions herein may also be applied to laundry or dishwashing, for example, as a laundry or dishwashing tablet, block, cylinder, cube, sheet or other non-particulate configuration.
Preferably, the water-soluble coating is formed from an organic hydrophilic monomer, which is even more preferably selected from the group consisting of acrylates, methacrylates, acrylamides, methacrylamides, maleates, fumarates, vinyl ethers and mixtures thereof. More preferably, the organic monomer is selected from the group consisting of 2-hydroxyethyl methacrylate, N,N-dimethylacrylamide, acrylic acid, methacrylic acid and mixtures thereof. Most preferably, the organic monomer is acrylic acid.
The water-soluble coating is on at least a portion of the detergent compositions described herein. By xe2x80x9cat least a portionxe2x80x9d, it is meant that at least 1%, preferably 90% to 100% of the particulate or non-particulate detergent composition has a water-soluble coating on it. It should be understood that not all of the detergent composition needs to be coated to be within the scope of the invention. To that end, a plasma coating process is used to place the water-soluble coating on the detergent composition. As detailed hereinafter, this is accomplished by ionizing a gas, such as argon, using high frequency electricity in a plasma vacuum chamber. Suitable gases may be selected from the group consisting of argon, helium, oxygen, nitrogen and mixtures thereof.
Typical plasma chambers will have a xe2x80x9cplasma glow zonexe2x80x9d which can be the region between the two electrodes used to generate the high frequency electricity, and thus the plasma therebetween. The plasma chamber can be embodied in a fluidized bed dryer or cooler, tumbling drum, vibrating conveyor belt or other similar apparatus used in the commercial scale production of particulate detergent compositions. The pressure inside the plasma chamber is typically maintained at a pressure of from about 5 mTorr to about 300 Torr, preferably from about 10 mTorr to about 1 Torr, and most preferably from about about 50 mTorr to about 250 mTorr. The power used in the plasma coating is preferably from about 0.1 Watts to about 500 Watts, more preferably from about 0.5 Watts to about 100 Watts, and most preferably from about 1 Watt to about 10 Watts. In this way, the plasma coating process can be controlled so as not to destroy the functional attributes of the coating or the particulate material being plasma coated in accordance with the invention.
As used herein, the phrase xe2x80x9cplasma-inducedxe2x80x9d means that which has been deposited, coated or otherwise layered using one or more of plasma deposition techniques which should be contrasted with simple spraying techniques that do not employ gas ionized with electricity. This application of a high frequency electric field to a gas to form a plasma of gas ions is a known technique used in polymerization of monomers such as organic hydrophilic monomers which are suitable for use herein to form the water-soluble coating on the detergent composition. This technique has been described, for example, in Luster, U.S. Pat. No. 2,257,177. In general, this involves continuous contact of the polymerizing monomer in the vapor phase with the gas plasma until substantial completion of the graft polymerization on the substrate. This technique tends to form a cross-linked product as suggested by U.S. Pat. No. 3,287,242. Due to the high cross-linking associated with plasma polymerization, that technique is generally employed for the purpose of forming water-insoluble thin films or coatings rather than water-soluble coatings as currently contemplated by the invention. The activation is confined to a region near the surface of the substrate at which links and cross-links are formed.
One modification of the film/coating forming techniques in which the monomer is polymerized directly from the gas state is described in Knox et al, U.S. Pat. No. 3,475,307. There, the substrate is cooled to condense a thin layer of liquid monomer on the substrate in order to increase the polymerization rate. However, in that technique, the ordinary skilled artisan must avoid condensing xe2x80x9ctoo muchxe2x80x9d of the monomer on the surface because otherwise the incoming activated molecules from the gas phase would not reach the monomer removed from the gas liquid interface which is stated to cause a coating of little adherence (col. 10, lines 54-60). The order of magnitude of condensed monomer prior to polymerization is indicated as being few molecules in thickness (col. 4, lines 1-4).
Another plasma coating technique is to initiate polymerization by use of a non-equilibrium ionized gas plasma and to complete the majority of the polymerization in the absence of the plasma. In this manner, a high molecular weight polymer is formed. The formation of the ionized gas plasma may be accomplished in any of the techniques known to produce such plasmas. For example, see J. R. Hollahan and A. T. Bell, eds., xe2x80x9cTechniques in Applications of Plasma Chemistryxe2x80x9d, Wiley, New York, 1974 and M Shen, ed. xe2x80x9cPlasma Chemistry of Polymersxe2x80x9d, Marcel Dekker, New York, 1976. In one technique, an ionizable gas is contained under vacuum between parallel plate electrodes connected to a radio frequency generator which is sold by International Plasma Corporation under the designation xe2x80x9cModel 3001xe2x80x9d. The plasma can be created with such parallel plates either external or internal to the plasma chamber. In another technique, an external induction coil creates an electric field which produces the plasma of ionized gas. In yet another technique, oppositely charged electrode points are placed directly into the plasma vacuum chamber in spaced apart relationship to create the plasma. Any plasma formed by these techniques or any other one in which an electric field creates a path of electrical conduction totally within the gas phase is suitable for use in the invention.
As used herein, the term xe2x80x9cplasmaxe2x80x9d is to be distinguished from any liquid or solid environment in which an electric field is applied to create ions in a path through the solid or liquid. This is not to exclude the possibility that an electric field would also be applied across the non-vapor monomer. However, if it were, it is not believed that it would have any beneficial function; instead, it would be extraneous to the vapor phase plasma. The operating parameters for the plasma vary from monomer to monomer. In general, it is preferable to employ reduced gas pressures to form a glow discharge by electron liberation which causes ionization in the gas phase. Where a plasma is created in a chamber including a monomer gas at a pressure below atmospheric pressure, the plasma is formed when the interelectrode potential exceeds a threshold value which is sufficient to ionize or xe2x80x9cbreakdownxe2x80x9d the gas. This is a function of the composition of the gas, its pressure and the distance between the electrodes. After breakdown, the gas is conductive and a stable plasma may be maintained over a wide range of currents. Although the exact composition of the plasma is not known, it is believed to include electrons, ions, free radicals, and other reactive species.
The free radicals and/or ions in the plasma may be supplied by collision of plasma electrons with monomer vaporized from the non-vapor monomer to be polymerized. The monomer may be in the form of a liquid, a solid, or a solid-liquid mixture. For the liquid monomer, the monomer vapor is supplied by evaporation of monomer into the plasma which is facilitated by the application of a vacuum. Similarly, for the solid monomer, such free radicals and/or ions are supplied by sublimed monomer vapor. For simplicity of description, the non-vapor monomer to be activated will be described herein as being in the liquid state unless otherwise specified.
In a related procedure, the creation of active sites in the monomer may be facilitated by direct activation from the ionized gas, itself, in the plasma. For this purpose, the presence of any ionizable gas under the conditions prevalent in the plasma may be employed. For example, water vapor may be ionized to create active polymerization sites for certain monomers. Other gases which have been ionized by such plasmas include hydrogen chloride, carbon tetrachloride, and inert gases such as helium or neon. Those gases which are ionizable in the plasma are well known to those in the field. The monomer to be activated may be in the essentially pure monomeric state or in solution. In the latter instance, organic or inorganic solvents capable of complete dissolution of the monomer may be employed. Typical organic solvents for certain monomers include benzene and acetone. When a glow-discharge type of plasma is employed, excess vaporization of monomer may interfere with the plasma. Thus, when a pure normally liquid monomer of relatively high vapor pressure is employed, it is desirable to reduce its vapor pressure. For warmed to a mixed solid-liquid state prior to plasma initiation.
For any given plasma deposition technique as described herein, the process may involve the use of high frequency microwaves to ionize the gas in the plasma chamber. Alternatively, high frequency radio waves or direct current electricity can be used, for example to ionize the gas between two oppositely charged electrode points used to define the plasma glow zone in a plasma vacuum chamber. Another option is to pulsate or otherwise intermittently ionize the gas in the plasma glow zone in the plasma chamber so as to control the plasma-induced deposition of the monomer onto the particulate detergent material. Further control of plasma-induced deposition can be achieved in the process of the present invention by positioning the particulate detergent material to be coated with the hydrophilic monomer outside of the plasma glow zone. Alternatively or additionally, the water-soluble hydrophilic monomer may be introduced outside of the plasma glow zone, as well, to provide further control of the deposition.
As mentioned previously, the water-soluble coating is formed from an organic hydrophilic monomer, some of which are mentioned above. The detergent compositions preferably contain an effective amount of such monomer so as to achieve the desired solubility, flowability and/or chemical stability of the particulate or non-particulate composition. In typical formulations, the coating which is formed of the monomer grafted onto the particulate or non-particulate composition will have a thickness in the range of from about 0.001 microns to about 1000 microns, more preferably from about 0.05 microns to about 50 microns and most preferably from about 0.01 microns to about 10 microns.
Suitable organic hydrophilic monomers include generally water soluble conventional vinyl monomers such as: acrylates and methacrylates of the general structure
where R2 is hydrogen or methyl and R3 is hydrogen or is an aliphatic hydrocarbon group of up to about 10 carbon atoms substituted by one or more water solublizing groups such as carboxy, hydroxy, amino, lower alkylamino, lower dialkylamino, a polyethylene oxide group with from 2 to about 100 repeating units, or substituted by one or more sulfate, phosphate, sulfonate, phosphonate, carboxamido, sulfonamido or phosphonamido groups, or mixtures thereof; acrylamides and methyacrylamides of the formula
where R2 and R3 are as defined above; acrylamides and methyacrylamides of the formula
where R4 is lower alkyl of 1 to 3 carbon atoms and R2 is as defined above; maleates and fumarates of the formula
R3OOCHxe2x95x90CHxe2x80x94COOR3
wherein R3 is as defined above; vinyl ethers of the formula
H2Cxe2x95x90CHxe2x80x94Oxe2x80x94R3
where R3 is as defined above; aliphatic vinyl compounds of the formula
R2CHxe2x80x94CHR3
where R2 is as defined above and R3 is as defined above with the proviso that R3 is other than hydrogen; and vinyl substituted heterocycles, such as vinyl pyridines, piperidines and imidazoles and N-vinyl lactams, such as N-vinyl-2-pyrrolidone.
Included among the useful water-soluble monomers are: 2-hydroxyethyl-, 2- and 3-hydroxypropyl-, 2,3-dihydroxypropyl-, polyethoxyethyl-, and polyethoxypropyl acrylates, methacrylates, acrylamides and methacrylamides; acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide; N, N-dimethyl- and N, N-diethyl-aminoethyl acrylate and methacrylate and the corresponding acrylamides and methacrylamides; 2- and 4-vinylpyridine; 4- and 2-methyl-5-vinylpyridine; N-methyl-4-vinylpiperidine; 2-methyl-1-vinylimidazole; N, N-dimethylallyalamine; dimethylaminoethyl vinyl ether, N-vinylpyrrolidone; acrylic and methacrylic acid; itaconic, crotonic, fumaric and maleic acids and the lower hydroxyalkyl mono and diesters thereof, such as the 2-hydroxyethyl fumarate and maleate, sodium acrylate and methacrylate; maleic anhydride; 2-methacryloyloxyethylsulfonic acid and allylsulfonic acid, dimethylacrylamide; acrylic acid and methacrylic acid; and most preferably 2-hydroxyethyl methacrylate.
The particulate and non-particulate detergent compositions described herein preferably contain a detersive surfactant and a detergent builder, and optionally, a variety of common detergent ingredients. The surfactant system of the detergent composition may include anionic, nonionic, zwitterionic, ampholytic and cationic classes and compatible mixtures thereof. Detergent surfactants are described in U.S. Pat. No. 3,664,961, Norris, issued May 23, 1972, and in U.S. Pat. No. 3,919,678, Laughlin et al., issued Dec. 30, 1975, both of which are incorporated herein by reference. Cationic surfactants include those described in U.S. Pat. No. 4,222,905, Cockrell, issued Sep. 16, 1980, and in U.S. Pat. No. 4,239,659, Murphy, issued Dec. 16, 1980, both of which are also incorporated herein by reference.
Nonlimiting examples of surfactant systems include the conventional C11-C 18 alkyl benzene sulfonates (xe2x80x9cLASxe2x80x9d) and primary, branched-chain and random C10-C20 alkyl sulfates (xe2x80x9cASxe2x80x9d), the C10-C18 secondary (2,3) alkyl sulfates of the formula CH3(CH2)x(CHOSO3xe2x88x92M+) CH3 and CH3 (CH2)y(CHOSO3xe2x88x92M+) CH2CH3 where x and (y+1) are integers of at least about 7, preferably at least about 9, and M is a water-solubilizing cation, especially sodium, unsaturated sulfates such as oleyl sulfate, the C10-C18 alkyl alkoxy sulfates (xe2x80x9cAEXSxe2x80x9d; especially EO 1-7 ethoxy sulfates), C10-C18 alkyl alkoxy carboxylates (especially the EO 1-5 ethoxycarboxylates), the C10-C18 glycerol ethers, the C10-C18 alkyl polyglycosides and their corresponding sulfated polyglycosides, and C12-C18 alpha-sulfonated fatty acid esters. If desired, the conventional nonionic and amphoteric surfactants such as the C12-C18 alkyl ethoxylates (xe2x80x9cAExe2x80x9d) including the so-called narrow peaked alkyl ethoxylates and C6-C12 alkyl phenol alkoxylates (especially ethoxylates and mixed ethoxy/propoxy), C12-C18 betaines and sulfobetaines (xe2x80x9csultainesxe2x80x9d), C10-C18 amine oxides, and the like, can also be included in the surfactant system. The C10-C18 N-alkyl polyhydroxy fatty acid amides can also be used. Typical examples include the C12-C18 N-methylglucamides. See WO 9,206,154. Other sugar-derived surfactants include the N-alkoxy polyhydroxy fatty acid amides, such as C10-C18 N-(3-methoxypropyl) glucamide. The N-propyl through N-hexyl C12-C18 glucamides can be used for low sudsing. C10-C20 conventional soaps may also be used. If high sudsing is desired, the branched-chain C10-C16 soaps may be used. Mixtures of anionic and nonionic surfactants are especially useful. Other conventional useful surfactants are listed in standard texts.
The detergent composition can, and preferably does, include a detergent builder. Builders are generally selected from the various water-soluble, alkali metal, ammonium or substituted ammonium phosphates, polyphosphates, phosphonates, polyphosphonates, carbonates, silicates, borates, polyhydroxy sulfonates, polyacetates, carboxylates, and polycarboxylates. Preferred are the alkali metal, especially sodium, salts of the above. Preferred for use herein are the phosphates, carbonates, silicates, C10-18 fatty acids, polycarboxylates, and mixtures thereof. More preferred are sodium tripolyphosphate, tetrasodium pyrophosphate, citrate, tartrate mono- and di-succinates, sodium silicate, and mixtures thereof (see below).
Specific examples of inorganic phosphate builders are sodium and potassium tripolyphosphate, pyrophosphate, polymeric metaphosphate having a degree of polymerization of from about 6 to 21, and orthophosphates. Examples of polyphosphonate builders are the sodium and potassium salts of ethylene diphosphonic acid, the sodium and potassium salts of ethane l-hydroxy-1,1-diphosphonic acid and the sodium and potassium salts of ethane, 1,1,2-triphosphonic acid. Other phosphorus builder compounds are disclosed in U.S. Pat. Nos. 3,159,581; 3,213,030; 3,422,021; 3,422,137; 3,400,176 and 3,400,148, all of which are incorporated herein by reference.
Examples of nonphosphorus, inorganic builders are sodium and potassium carbonate, bicarbonate, sesquicarbonate, tetraborate decahydrate, and silicates having a weight ratio of SiO2 to alkali metal oxide of from about 0.5 to about 4.0, preferably from about 1.0 to about 2.4. Water-soluble, nonphosphorus organic builders useful herein include the various alkali metal, ammonium and substituted ammonium polyacetates, carboxylates, polycarboxylates and polyhydroxy sulfonates. Examples of polyacetate and polycarboxylate builders are the sodium, potassium, lithium, ammonium and substituted ammonium salts of ethylene diamine tetraacetic acid, nitrilotriacetic acid, oxydisuccinic acid, mellitic acid, benzene polycarboxylic acids, and citric acid.
Polymeric polycarboxylate builders are set forth in U.S. Pat. No. 3,308,067, Diehl, issued March 7, 1967, the disclosure of which is incorporated herein by reference. Such materials include the water-soluble salts of homo- and copolymers of aliphatic carboxylic acids such as maleic acid, itaconic acid, mesaconic acid, fumaric acid, aconitic acid, citraconic acid and methylenemalonic acid. Some of these materials are useful as the water-soluble anionic polymer as hereinafter described, but only if in intimate admixture with the nonsoap anionic surfactant.
Other suitable polycarboxylates for use herein are the polyacetal carboxylates described in U.S. Pat. No. 4,144,226, issued Mar. 13, 1979 to Crutchfield et al., and U.S. Pat. No. 4,246,495, issued Mar. 27, 1979 to Crutchfield et al., both of which are incorporated herein by reference. These polyacetal carboxylates can be prepared by bringing together under polymerization conditions an ester of glyoxylic acid and a polymerization initiator. The resulting polyacetal carboxylate ester is then attached to chemically stable end groups to stabilize the polyacetal carboxylate against rapid depolymerization in alkaline solution, converted to the corresponding salt, and added to a detergent composition. Particularly preferred polycarboxylate builders are the ether carboxylate builder compositions comprising a combination of tartrate monosuccinate and tartrate disuccinate described in U.S. Pat. No. 4,663,071, Bush et al., issued May 5, 1987, the disclosure of which is incorporated herein by reference.
Water-soluble silicate solids represented by the formula SiO2.M2O, M being an alkali metal, and having a SiO2:M2O weight ratio of from about 0.5 to about 4.0, are useful salts in the detergent granules of the invention at levels of from about 2% to about 15% on an anhydrous weight basis, preferably from about 3% to about 8%. Anhydrous or hydrated particulate silicate can be utilized, as well.
Any number of additional ingredients can also be included as components in the granular detergent composition. These include other detergency builders, bleaches, bleach activators, suds boosters or suds suppressors, anti-tarnish and anti-corrosion agents, soil suspending agents, soil release agents, germicides, pH adjusting agents, nonbuilder alkalinity sources, chelating agents, smectite clays, enzymes, enzyme-stabilizing agents and perfumes. See U.S. Pat. No. 3,936,537, issued Feb. 3, 1976 to Baskerville, Jr. et al., incorporated herein by reference.
Bleaching agents and activators are described in U.S. Pat. No. 4,412,934, Chung et al., issued Nov. 1, 1983, and in U.S. Pat. No. 4,483,781, Hartman, issued Nov. 20, 1984, both of which are incorporated herein by reference. Chelating agents are also described in U.S. Pat. No. 4,663,071, Bush et al., from Column 17, line 54 through Column 18, line 68, incorporated herein by reference. Suds modifiers are also optional ingredients and are described in U.S. Pat. Nos. 3,933,672, issued Jan. 20, 1976 to Bartoletta et al., and 4,136,045, issued Jan. 23, 1979 to Gault et al., both incorporated herein by reference.
Suitable smectite clays for use herein are described in U.S. Pat. No. 4,762,645, Tucker et al., issued Aug. 9, 1988, Column 6, line 3 through Column 7, line 24, incorporated herein by reference. Suitable additional detergency builders for use herein are enumerated in the Baskerville patent, Column 13, line 54 through Column 16, line 16, and in U.S. Pat. No. 4,663,071, Bush et al., issued May 5, 1987, both incorporated herein by reference.
The following examples are presented for illustrative purposes only and are not to be construed as limiting the scope of the appended claims in any way.

Detergent composition having a plasma-induced, water-soluble coating and process for making same


A vehicle includes a motorized belt track directly or indirectly connected to a frame. The belt track frictionally contacts a drive surface on which the vehicle moves, such as any form of road or off-road surface. The belt track moves forward and backward in a direction parallel to a centerline of the belt track to move the vehicle backward and forward along the drive surface. A steering appendage is also directly or indirectly connected to the frame. The steering appendage is also adapted to frictionally contact the drive surface. The steering appendage is off the centerline of the belt track. The steering appendage causes the vehicle to turn from the centerline of the belt track when in contact with the drive surface.

The invention generally relates to a vehicle (large or small), cart, robot, etc. that uses a mono-track (e.g., single-track or uni-track) for its main motion in place of wheels or multiple tracks, although the invention could be applied to multi-track and wheeled vehicles as an aid toward turning. The mono-track vehicle (MTV) steers with a set of appendages that extend from the sides of the vehicle. These steering appendages steer by either causing drag on one side of the vehicle or by titling the vehicle to one side so as to cause the MTV to turn. The MTV has several uses including a radio controlled car, a platform for a metal detection sensor system, etc.
The vehicle disclosed herein includes some form of frame and a motorized belt track directly or indirectly connected to the frame. For example, the belt track can be supported by powered or unpowered wheels, rollers, ball bearings, etc. that are directly or indirectly connected to the frame. The belt track frictionally contacts a drive surface on which the vehicle moves, such as any form of road or off-road surface. The belt track moves (drives) forward and backward in a direction parallel to a center line of the belt track to move the vehicle backward and forward along the drive surface.
The steering appendage is adapted to frictionally contact the drive surface. The steering appendage is off the center line of the belt track, and causes the vehicle to turn from the center line of the belt track when in contact with the drive surface. The steering appendage is adapted to be moved, such that the steering appendage can be selectively placed in contact with the drive surface and selectively removed from the drive surface. The steering appendage comprises an arm and a contact pad. A pivot joint can be used to directly or indirectly connect the steering appendage to the frame.
Embodiments herein therefore provide a method of controlling a travel direction of a mono-track vehicle. This method moves the motorized belt track along the drive surface and frictionally contacts the steering appendage to the drive surface. Because the steering appendage is off the center line of the belt track, the steering appendage causes the vehicle to turn from the center line of the belt track when in contact with the drive surface.
These, and other, aspects of the present invention will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following description, while indicating preferred embodiments of the present invention and numerous specific details thereof, is given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.


A low power high efficiency switching power supply comprises a switching transducer having primary and secondary windings. The primary winding is supplied with a primary voltage over a series connected constant current source and Zener diode. The primary voltage is chopped by an FET which has a gate connected to an oscillator operating at relatively low frequency. The secondary windings of the transformer are connected to full-wave rectifiers which convert the A.C. signal produced by the chopping of the primary voltage, int a D.C. signal. Efficiency is maximized by using fast switching FET's and low flux densities in the transformer. The power supply is particularly useful in 4-20 mA current loops.

The present invention relates in general to precision power supplies and in particular to a new and useful low power, high efficiency switching power supply which is particularly useful for powering a 4 to 20 mA current loop.
Normally, low power supply is of less than 50 mW, with split voltage sources (+ voltages) are accomplished by establishing a floating common (elevated) or by a low efficiency switching power supply. It is imperative however that a power supply operating from a 4-20 mA current loop be highly efficient to maximize circuit functions.
Two-wire analog transmission systems are well known. Such systems include a transmitter which is connected to a power supply by two wires which form a current loop. The transmitter includes, as at least one of its features, a transducer which senses a condition such as pressure or temperature. This condition is know as a process variable (PV).
A power supply is connected to the two wires to close the current loop. It is also conventional to provide a resistor in the current loop. The transmitter amplifies the signal from its transducer and this amplified signal is used to draw a certain current from the power supply which is proportional or otherwise related to the process variable. It is conventional to draw from a minimum of 4 (mA) to a maximum of 20 mA. The current between 4 and 20 mA passes through the resistor to produce a voltage drop across the resistor. This voltage drop can be measured to give a value for the process variable.
It is noted that the 4 mA minimum current is required to energize the circuitry of the transmitter. Any excess current above this 4 mA level is taken as a value which can be used to determine the process variable.
It is known that such 4-20 mA two-wire systems have an accuracy which is limited to around 0.1% at best. These systems are also essentially unidirectional with the transmitter being essentially uncontrolled and transmitting continuously.

Low power high efficiency switching power supply


Dry film resists of the invention in general comprise a photoactive component, a highly viscous or solid (at room temperature, ca. 25xc2x0 C.) crosslinker component, and preferably a flexibilizing agent. Preferred dry film constructions of the invention do not require the use of a protective cover sheet due to the composition""s very dry nature.

1. Field of the Invention
The present invention relates to new photoresist dry film constructions and compositions. Preferred dry film of the invention are characterized as including a base carrier sheet, but without any type of cover sheet. These preferred dry film resists can be photoimaged in the absence of the carrier sheet, enabling significant cost and waste reductions as well as significant improvements in resolution of the patterned resist.
2. Background
Photoresists are photosensitive films used for the transfer of images to a substrate. A coating layer of a photoresist is formed on a substrate and the photoresist layer is then exposed through a photomask to a source of activating radiation. The photomask has areas that are opaque to activating radiation and other areas that are transparent to activating radiation. Exposure to activating radiation provides a photoinduced chemical transformation of the photoresist coating to thereby transfer the pattern of the photomask to the photoresist-coated substrate. Following exposure, the photoresist may be developed in a suitable developer to provide a relief image that permits selective processing of a substrate.
Photoresists are often formulated and applied as liquid compositions and the liquid carrier is removed after coating onto a substrate surface.
For many applications however including printed circuit board manufacture, dry film resists are frequently employed. See, for instance, U.S. Pat. Nos. 5,300,913, 4,943,513 and 4,610,951 for background on dry film resists. Such resists are applied as a solid (dry film) coating layer to a copper laminate or other substrate. A typical dry film contains a base or carrier sheet over which is coated a photoimageable composition with subsequent removal of the composition liquid carrier. Polyethylene terephthalate (PET) is a common carrier sheet.
To protect the unprotected surface of the photoimageable coating and to facilitate rolling of the carrier sheet/photoimageable construction, the unprotected composition surface is covered with a removable protective sheet such as a polyethylene (PE) layer, polypropylene layer or a polyethylene terephthalate (PET) layer.
Despite the nomenclature, a typical dry film photoresist is a highly viscous liquid that contains a certain amount of tack after drying. As a result, when a carrier sheet (e.g. PET) is coated and the photoresist is applied and dried, a protective cover sheet such as polyethylene is required. Without that cover sheet, the photoresist would adhere to the backside of the PET when it is wound around a plastic core into a roll, which is a typical dry film construction form.
In use, the cover sheet (typically PE) is removed from the dry film construction and the exposed side is applied to a copper laminate or other substrate surface. The PET carrier sheet remains, overlaying the photoresist through exposure. A sheet that contains the desired pattern (photomask) is placed on top of the PET carrier sheet and through which activating radiation is applied and the pattern is transferred to the resist. The carrier sheet is required through exposure. If the carrier sheet were removed prior to exposure, the photomask sheet would adhere to the surface of the tacky photoresist.
Hence, the PET or other carrier sheet must have high optical quality to avoid undesired interference with the radiation passed therethrough to the resist layer. Interference with the exposure radiation can compromise resolution of the image patterned into the resist layer and transferred to the underlying copper or other substrate surface. After the exposure step, the carrier sheet is removed and discarded in order to permit development of the latent image patterned in the resist layer.
Moreover, as a viscous liquid sandwiched between the carrier and protective sheets, the dry film is subject to flow over time. Such xe2x80x9ccoldxe2x80x9d flow can result in thin spots, thin lines, or other areas where film thickness is less than desired, all of which can significantly compromise lithographic performance and reduce production yields. In particular, any surface protrusions in the carrier and protective sheets will cause thin spots and voids. Such protrusions are generally present in the PE cover sheet. Additionally, flow can occur at the end of a dry film roll where resist flows out and fuses with other areas of flow. Such end flow requires slitting of the end prior to use of the dry film, resulting in significant waste and again potentially compromising lithographic results. Additionally, when the dry film is unwound, the xe2x80x9cfusedxe2x80x9d resist will flake and can be caught between the photoresist and substrate resulting in processing variations and subsequent yield losses.
It thus would be desirable to have new dry film constructions.
I have now found new photoresist compositions and dry film constructions that are highly useful in negative-tone dry film resist constructions.
Preferred dry film resist constructions of the invention do not require the use of a protective cover sheet due to the resist""s very dry nature. In particular, because of such high dryness of the composition, a carrier sheet (e.g. PET) is not required during the exposure step since the pattern containing sheet (photomask) will not adhere to the resist composition during exposure. Moreover, enhanced resolution of the image patterned in the resist can result since the carrier sheet (e.g. PET) will not be present to potentially interfere (e.g. diffraction or other optical interference) with the exposure radiation.
Dry film resists of the invention preferably comprise at least a photoactive component, and a highly viscous or solid (at room temperature, ca. 25xc2x0 C.) crosslinker component. A flexibilizing agent also may be added, e.g. depending on other resist composition choices. Additionally, a film forming polymer can be added to aid in coating and processing of the resist.
The crosslinker component of prior dry film resists conventionally has been comprised in at least significant part of one or more monomers (e.g. unsaturated compounds) or other relatively low molecular weight compounds. It has been found that such low molecular crosslinkers are a predominant cause of undesired cold flow during storage of a dry film resist roll.
I have found that use of oligomeric or other higher molecular weight crosslinkers can provide a dry film resist that is essentially dry and tack free. In fact, unlike prior dry film compositions, resist compositions of the invention have melt point or sharp Tg, e.g. about 35xc2x0 C. or 40xc2x0 C. or greater, more preferably about 45xc2x0 C. or 50xc2x0 C. or greater. Exemplary preferred crosslinkers include acrylated urethanes, preferably having a weight average molecular weight of at least about 500 daltons, more typically an Mw of from about 500 to 100,000, still more typically from about 1,000 to 50,000. Another preferred crosslinker is an acrylate oligomer, typically having a weight average molecular weight of from about 100 to 5,000 daltons. In general, preferred crosslinkers of the compositions of the invention will have a molecular weight of at least about 400 daltons, more preferably at least about 500, 600, 700, 800, 900 or 1000 daltons. Generally preferred crosslinkers are polymeric compounds. Generally preferred compositions of the invention contain a crosslinker component that is predominately (greater than 50 weight %) comprised of compounds having a molecular weight (Mw) of about 15,000 daltons or greater, more preferably a molecular weight (Mw) of about 75,000 or greater. Even more preferably, the crosslinker is comprised of at least about 30, 50, 60, 70, 80, 90, or even 95 weight percent of such high molecular weight crosslinker compounds. The crosslinker component may contain a relatively minor portion of low molecular weight monomer-type compounds, although such use of such compounds is less preferred.
In preferred compositions, a film forming polymeric material may be added that has a Tg sufficiently high to allow use of low molecular weight materials while maintaining an overall compositional Tg above room temperature.
I have also found that the further use of a flexibilizing agent can be preferred. Among other things, use of flexibilizing agent allows composition choices to be broadened and allows the use of materials that can enhance a resist""s overall profile but that may embrittle the resist. More particularly, the use of a flexibilizing agent enables the resist composition to exhibit sufficient flexibility to enable forming a roll of the resist, without cracking or other degradation. A variety of compositions may be suitably employed as the flexibilizing agent. Preferred materials are straight chain oligomers or polymers, preferably containing hetero atoms (particularly O or S) to facilitate intermixing of the flexibilizing agent with other composition components. For example, a preferred flexibilizing agent is POLYMEG 650 (from Quaker Chemical). Additional suitable flexibilizing agents include an aliphatic urethane such as those commercially available from Sartomer. The flexibilizing material in this case can act as a reactive monomer.
Resist compositions of the invention further include a photoactive component, typically a free radical initiator. The resists of the invention also may include other additives such as adhesion promoters, dyes, leveling agents and the like as may be generally known.
Dry film resists of the invention preferably will be not only be dry and tack-free (e.g. by the tissue paper test as discussed below), but also exhibit a sharp Tg indicating a melting point of the composition. Such a sharp Tg enables lamination of the dry film resist to a substrate (e.g. via hot roll laminator under conditions to enable melting of the resist) with the resist adhering to the substrate and exhibiting sufficient fluid characteristics to fill imperfections in the substrate surface.
The invention also includes the construction or rolls of dry film resists of the invention, and articles of manufacture such as a printed circuit board substrate or other electronic packaging substrate coated with a dry film resist of the invention. Dry film rolls of the invention preferably do not include a protective cover sheet, and comprise a resist of the invention coated on a base carrier sheet, including with the resist layer rolled directly onto itself (i.e. without any type of interposed cover sheet). That is, the rolled construction includes the coated sheet rolled directly up onto itself, with the unprotected surface of the resist in direct contact with the reverse side of the carrier sheet.
The invention also includes methods for forming a relief image of a dry film resist of the invention, which method does not require removal of a protective carrier sheet of the dry film construction. Artwork (photomask) can be placed directly on the dry film carrier sheet or resist top surface during imaging.
Methods of the invention also can not include a step of removal of a carrier sheet from the dry film resist (particularly where such a sheet is not employed). Additional preferred methods include that may employ a dry film construction that does has a protective cover sheet, but the cover sheet is removed prior to imaging and artwork (photomask) is placed directly on the dry film top surface.
Other aspects of the invention are discussed infra.
As discussed above, dry film photoresists of the invention are substantially xe2x80x9cdrierxe2x80x9d than prior dry film resist compositions, enabling fabrication of the dry film construction without the use of a protective cover sheet, thereby providing significant cost and waste savings and images of enhanced resolution.
Preferred levels of xe2x80x9cdrynessxe2x80x9d of dry films of the invention can be assessed in a number of ways. A preferred method is a xe2x80x9ctissue paper testxe2x80x9d which includes pressing a tissue paper into a photoresist layer by hand manipulation and then manually removing the tissue paper. Dryness or tackiness of the resist layer is measured by ease of removal for the tissue paper. Specifically, a tacky dry film will result in tear or other such degradation of the tissue paper upon attempts to remove the impressed paper. A preferred xe2x80x9cdryxe2x80x9d resist of the invention will enable removal of the tissue paper without leaving an imprint (naked eye inspection) on the resist surface.
The use of the highly viscous or solid (room temperature) crosslinker component together with a flexibilizing agent provides a dry film construction that is substantially resistant to cold flow, yet reasonably flexible to enable forming a dry film roll without breakage or other degradation of the rolled resist.
Resists of the invention may be suitably a primary imaging resist e.g. for forming a printed circuit board, or alternatively may be a permanent photoimageable coating e.g. to function as a solder mask, permanent inner layer, advanced dielectric, chip scale packaging, or the like in an electronic packaging substrate such as a printed circuit board.
As discussed above, resists of the invention further contain a photoactive component, which preferably comprises one or more free radical initiators such as IRAGACURE 184 from Ciba Geigy, isopropyl thioxanthone and the like.
The resist also may contain any number of additional ingredients including dyes, photosensitizers, leveling agents, adhesion promoters and the like. More particularly, various triazoles may be employed as adhesion promoters, such as benzatriazole and substituted benzatriazoles e.g. carboxy benzatriazole. Suitable dyes include solvent blue 57 and leuco crystal violet. Suitable leveling agents include Modaflow from Monsanto. Suitable antioxidants include triphenylphosphite and triphenylphosphine.
Dry film constructions of the invention are prepared by generally known methods. For example, all the resist components can be admixed in a solvent carrier and then coated onto a base or carrier sheet such as PET or other suitable material. The solvent carrier is then removed, e.g. by heating the coated sheet at from 80 to 120xc2x0 C. for about 3 to 30 minutes.
The dried resist layer then can be formed into a dry film roll, without any protective cover sheet being placed on the resist top surface. The dried film does not crack upon creasing or other manipulation that occurs in the roll formation. Prior dry film constructions are of such a tacky quality that they adhere to the backside of the carrier sheet when constructed into a roll and without use of a protective cover sheet. In contrast, photoresist compositions of the invention when wound into a roll will not transfer to the backside of a carrier sheet.
The dry film resist roll then can be directly applied e.g. by lamination to a substrate surface without the necessity of removal and disposal of a cover sheet as employed with prior dry film resist systems. The cover sheet is commonly considered hazardous waste due to the ability of the sheet to absorb reactive monomer. Dry film constructions of the invention may be suitably applied onto a wide variety of substrates, and preferably will be applied to a copper surface of a printed circuit board substrate. The resist is preferably laminated onto such a substrate followed by removal of the carrier sheet.
A dry film resist of the invention is preferably applied to a copper clad laminate (printed circuit board substrate) or other substrate via a hot roll laminator. Suitable hot roll laminator conditions include from about 150 to 300xc2x0 F., more preferably from about 200 to 280xc2x0 F., still more preferably from about 220 to 250xc2x0 F. The hot roll laminator pressure may be from about 20 to 50 psi, preferably about 25 to 35 psi. The speed of the laminator may be from 1 to 10 feet per minute (fpm), more preferably 2 to 8 fpm, still more preferably 3-6 fpm. The substrates may be pre-heated prior to entering the laminator.
After such application of the resist to the substrate, a photomask is placed on the resist in an exposure tool, and the resist is exposed to patterned activating radiation.
Typical prior dry film resists require the carrier sheet to remain on the photoresist during exposure as the artwork that carries the image that is to be transferred. As discussed above, the carrier sheet prevents the artwork from adhering to a tacky resist layer. However, the carrier sheet can interfere with the collimation of the activating radiation, particularly by surfaces of the carrier sheet reflecting and diffracting incident light. Consequently, current dry film resist systems often employ carrier sheets that are highly optically clear, which adds significantly to the expense of the sheet material and the dry film construction.
Film thickness is another limitation often encountered during dry film resist manufacture. Because typical dry film resists are highly viscous liquids, any imperfections in the cover sheet such as gel slugs can cause the resist to flow away from the point of stress, which can result in thin spots and voids. Such problems have been addressed by manufacturing the dry film resist to a thickness sufficient to consistently transfer the image to an underlying substrate, e.g. a dry film resist thickness of a minimum of about 1.3 mils up to a thickness of about 2 mils or more.
However, dry film resists of the invention can be manufactured at significantly decreased thicknesses. Because resists of the invention do not require protective cover sheets, resists of the invention do not require a thickness necessary to compensate for imperfections in the cover sheet. More particularly, dry film resists of the invention suitably may have a thickness of about 1.0 mil or less, preferably from about 0.1 to 1 mils, more preferably from about 0.2 to 0.8 mils, still more preferably from about 0.3 to about 0.5 or 0.8 mils.
The exposure is sufficient to effectively activate the photoactive component of the photoresist system to produce a patterned image in the resist coating layer and, more specifically, the exposure energy typically ranges from about 1 to 10 to 250 mJ/cm2, dependent upon the exposure tool and the components of the photoresist composition.
Following exposure, the film is developed to remove unexposed regions of the resist layer. An alkaline developer may be used if the resist contains a resin or other component with acid groups as discussed above. A preferred developer is a sodium carbonate aqueous solution, particularly a 1 wt % or 2 wt % carbonate aqueous solution. An acidic developer solution alternatively may be employed if the resist contains a resin or other component with basic groups to enable such development.
Following development of the photoresist coating over the substrate, the developed substrate may be selectively processed on those areas bared of resist, for example by chemically etching or plating substrate areas bared of resist in accordance with procedures known in the art. After such processing, resist may be removed from the processed substrate using known stripping procedures.
As discussed above, dry film resists of the invention preferably will be not only dry and tack-free (e.g. by the tissue paper test as discussed above), but also exhibit a sharp Tg indicating a melting point of the composition. Such a sharp Tg enables lamination of the dry flm resist to a substrate (e.g. via hot roll laminator under conditions to enable melting of the resist) with the resist adhering to the substrate and exhibiting sufficient fluid characteristics to fill imperfections in the substrate surface. More particularly, preferred compositions of the invention will exhibit a Tg above about 45xc2x0 C. or 50xc2x0 C., more preferably of at least about 60xc2x0 C., 70xc2x0 C. or 80xc2x0 C., still more preferably at least about 90xc2x0 C., 100xc2x0 C., 110xc2x0 C. or 120xc2x0 C.


An inexpensive injection device is provided which is manufactured of plastic components, and is adapted to fit various syringe sizes. The injection device is spring loaded, and provides a firing barrel which, in the cocked position, is offset slightly from the central bore of the device.. When the device is fired, the firing barrel is aligned with the central bore and projects the needle portion of the syringe into the user.. For obtaining blood samples, the syringe is replaced by a striker element, which actuates a spring loaded puncture module which punctures the skin and is quickly withdrawn.

This invention relates to a plastic injector device which may be loaded, cocked and fired with ease. The injector may be readily applied to any part of the user's body to obtain an accurate injection site. The device may also be readily modified to obtain blood samples, and functions in the same mode as the injector.
Many patents disclose the use of hypodermic injector devices, such as U.S. Pat. No. 4,601,708 by Pavel Jordan, to the assignee, herein. The '708 patent is a highly durable device constructed of stainless steel and is quite effective. However, like many similar devices manufactured of metal components, it is expensive, and if lost or stolen or misplaced, would represent an inconvenient financial loss to the owner.
By comparison, an injector constructed of plastic components is far less expensive, and this is of particular importance to many persons. In addition, an injector device is desired in which the amount of liquid in the syringe barrel can be easily ascertained. Frequently, individuals who use injector devices, particularly diabetics, cannot see the syringe scale too well. Consequently, in the case of a plastic injector, it would be very helpful to provide a magnifier of some type to enlarge the scale portion of the syringe. However, in the case of a metal injector, this is difficult and usually requires some type of significant design feature which tends to be expensive.
In many instances, diabetics do not use a specific amount of insulin at given times, but instead employ blood tests in conjunction with a kit to determine their blood sugar content, and hence their insulin dosage. This of course necessitates pricking the skin to obtain a small blood sample. It would be both convenient and less expensive if the same device which was used as an injector could also be used, albeit with some modifications, for obtaining a blood sample.

Plastic device for injection and obtaining blood samples


The invention is wheel cover shield apparatus for masking a wheel or a wheel cover during the application of a spray foam cleaner of tire gloss. The apparatus includes a flanged concave round base that has an ergonomic apical non-slip handle and a planar sectional outer flange with an engaging locking means. The apparatus also includes at least one substantially planar ring for a given diameter wheel. Each ring is interchangeable with the base and has a variable width annular plane with an outer fillet edge and a coextensive inner flange. The inner flange has an engagable locking means. The engagable locking means has two to eight receptacles with a raised ridge or depression on the inner flange. The engaging locking means has two to eight sockets with a depression of raised ridge.

The present invention relates to apparatus for masking wheels, and more particularly to apparatus for protecting wheels while they are being washed or glossed.
The appearance and life of vehicular tires can be improved by cleaning (either by washing or applying a foaming tire cleaner), and/or then spraying on a tire gloss. The tire gloss and the foaming tire cleaner should be kept off the wheel as, at best they will leave a residue, and in some cases can stain or even be corrosive to the wheel or wheel cover (hub cap). Accordingly, there is a need for a protective removable wheel cover shield which will prevent mag wheels, customized wheels (i.e. chromed wheels, wheels with knock-offs), and wheel covers from being sprayed undesirably during the application of tire gloss or tire cleaner. The wheel cover shield preferably should be easily positioned over the wheel, held in place during spraying and easily removed. The wheel cover shield should preferably be available in various diameters to fit the assorted size wheels and wheel covers.
Applicant is aware of the following U.S. Patents concerning the art of protecting wheels during the application of tire gloss.
U.S. Pat. No. 4,874,206, Sampson discloses a mag tire wheel and wheel cover shield with a generally cylindrical flat flexible resilient disc of paper, plastic, or metal designed to cover the outer face of a mag tire wheel or wheel cover so that the tire can by sprayed with a polish or coating without spraying the wheel cover or mag wheel. The disc has a handle on the outer surface to help hold the disc against the mag wheel or wheel cover. A hard shield may extend outwardly from the disc handle to protect the user""s hand against spraying.
U.S. Pat. No. 5,423,599, Sherod et al. discloses a detachable wheel mask for temporarily covering an entire wheel of an automobile during washing and protecting the wheel from dirt while cleaning. The wheel mask includes a circular protective cover of a size corresponding with the wheel, a retaining element for fitting within a formed between the wheel rim and the tire to secure the protective cover to the wheel rim enclosing the wheel and a handle.
U.S. Pat. No. 5,524,972, Cailor et al. teaches that a wheel mask to protect the vehicle wheels during chemical treatment of the tires is a thin plastic molding having a circular concave body that includes a central hub having an exterior handle. The handle is inwardly open and formed of walls which project outwardly of the hub and are tapered to permit partial insertion of a handle of another mask, and the ridge walls are angled outwardly to enhance stacking of a plurality of masks.
U.S. Pat. No. 5,785,389, Bradford discloses a wheel and wheel cover shield having a resilient shield member surface defined partially by a curved shield edge and having a shield surface area less than the surface area of the wheel or wheel cover to be protected. A handle assembly extending from the shield member including a hand grip.
A desirable feature in a wheel cover shield is that it is non-abrasive so that during use the shield will not scratch the wheel or the wheel cover. Also desirable is that the shield is sufficiently flexible and conforming that it is sealing. Weights are usually added to the rim to balance the wheel mounted with a tire, and particularly with mag wheels the weights can interfere with the seal, thereby creating an opening that allows tire gloss spray to seep onto the wheel or wheel cover. The wheel cover shield is sufficiently flexible to at least partially deform, therein covering the protruding weight. Another problem commonly encountered during the use of wheel cover shields is caused by a protruding air stem. An air stem is located inboard of the rim, and can protrude beyond the rim, thereby preventing the shield from sealing. Long air stems are often found on wheels fitted with wheel covers that simulate spoked or mag wheels. The wheel cover shield must be stiff enough that it can deflect the air stem, thereby maintaining a seal between the shield and the rim.
Furthermore, the wheel cover shield should be relatively inexpensive, resistant to chemicals, and sufficiently shock resistant that it does not easily break if dropped. The handle must enable the user to securely grip the wheel cover shield, even when the shield is covered with a slippery liquid.
Additionally, the wheel cover shield preferably is adjustable such that a single wheel cover shield can be modified for masking a range of wheel diameters. The wheel cover shield should desirably have an adjustable means that is quick, simple, accurate and durable. For instance, the process of changing the wheel cover shield from a 13 inch diameter wheel shield to a 15 inch diameter wheel shield should be quick, where quick is under 30 seconds. The process should be simple, where simple is defined as not requiring tools. The process of changing the wheel cover shield from one diameter wheel shield to another diameter wheel shield should be accurate, where accurate is defined as reproducibly forming a wheel cover shield, wherein the diameter of the shield is within a few thousandths of an inch of the desired diameter, and the shield has substantially no elipticity (e.g. it is perfectly circular). The adjustable shield is durable, wherein durable is defined as forming a good seal, an effective mask, and where under normal use the shield is interlocked (e.g. the adjustable means does not become dislodged or loosened) and the shield still meets all the operative criteria as previously enumerated.
The wheel cover shield is comprised of a base that is a substantially concave round discoid that is stiffened with rib-like ridges, where said base has an ergonomic apical non-slip handle and a planar sectional outer flange that has an engaging locking means; and a ring for a given size wheel, where the ring is comprised of a specific width annular plane with a fillet edge and, coextensive with the annular plane, an inner flange, which has an engagable locking means; wherein when the base is fitted with any ring the outer flange overlaps and is coaxial with the inner flange; and the engaging locking means is reversible secured by the engagable locking means.
The ring for a given size wheel is appropriately sized by using a width of the annular plane that extends the diameter of the ring, such that the diameter is sufficient to extend the fillet edge slightly beyond the rim of the wheel. A wider wheel requires a wider ring, and there is correspondingly a ring with an annular plane having a greater breadth. The dimensions of the inner flange of the ring and the outer flange of the base stay constant. This constancy enables one base to be universally adaptable for mounting rings ranging from 12-25 inches. It is anticipated that the rings can also be constructed so that a smaller diameter base can be used with smaller diameter rings, and a larger diameter base can be use with larger diameter rings.
The preferred locking means is comprised of an engaging locking means and an engagable locking means, where the engagable locking means is a receptacle with a raised retaining ridge or a depression, and the engaging locking means is a socket with a depression or a raised resisting ridge, wherein following the insertion of the socket into the receptacle, the base and ring are reversibly locked. The planar sectional outer flange is preferably symmetrically sectioned, such that the outer flange is comprised of two to eight angular sectional lengths separated by a comparable number of angular sectional spaces where there is no flange. The width of any given angular sectional space is wider than the angular length of the receptacle on the inner flange, such that prior to locking the ring and the base, the receptacles on the inner flange are intermeshed between the angular sectional spaces of the outer flange and the inner flange is flush with the outer flange. The leading edge of an angular sectional length on the outer flange is in effect an angular socket. By holding the ring stationary and rotating the base, the angular sockets are plugged into the angular receptacles. Raised ridges or depressions within the receptacle and on the socket prevent the socket from becoming unplugged. The degree of difficulty of unplugging is controlled by varying the morphological features of the raised ridges or depressions on the socket and the receptacle. The relative rigidity of the receptacle also affects the degree of difficulty. In the instant invention, the locking means is designed to be relatively easy to unlock so that switching rings is quick and simple, and undue torque is not required. The ring will not become unlocked unless the ring held and the base is counter rotated, therein unplugging the angular sectional length from the corresponding receptacle. In a preferred embodiment of the invention, a leading edge of the angular section length has a radial ridge, and an entrance to the corresponding receptacle has a radial ridge, such that the socket can only enter when the entrance slightly widens under the force of the socket being pushed against the receptacle.
The base is preferably constructed so that it is relatively rigid through the selection of materials, reinforcement using ribbed ridges and the overall thickness of the base. The rings are constructed to be flexible enough so as to effect a good seal against the rim. The rings are preferably comprised of a plastic that is relatively tough. The fillet edge slopes away from the annular plane forming a lip that will slightly overlap the rim. The ring preferably does not have any ribbed ridges for reinforcement, but may have sectional lines along the perimeter of the inner flange to help center the base over the ring for a given size wheel.
The rings are preferably individually labeled with embossed or raised or decaled or printed lettering that indicates the wheel diameter. The wheel shield cover apparatus is used as follows. The diameter of the wheel is determined, and then the appropriate matching ring is mounted on the base. The shield is grasped and held with one hand, centered over the wheel, such that the rim and the rest of the wheel are masked. With another hand the spray is applied to the tire, and distributed smoothly over the tire.
The principal object of the invention is to provide an improved apparatus for protecting wheels and wheel covers during the application of tire gloss.
A further object of the invention is to provide an apparatus that will not be abrasive to a wheel or wheel cover.
Another object of the invention is to provide apparatus for shielding an assorted size of wheels and wheel configurations, wherein the diameter of the shield is adjustable, and the components of the apparatus are interchangeable.
A final object of the invention is to provide a wheel cover shield that has an adjustable means that is quick, simple, accurate and durable.