A packaged aqueous self foaming liquid cleansing composition comprising a base composition comprising a surfactant system comprising an anionic surfactant and an amphoteric or zwitterionic surfactant and a hydrophobic component, and a post foaming agent, wherein the composition is substantially free of soap and thickens on the addition of the post foaming agent to the base composition.

The present invention relates to detergent compositions suitable for topical application for cleansing the human body, such as the skin and hair. In particular, it relates to self foaming gel compositions, conveniently propellant driven and of the xe2x80x9cbag-in-canxe2x80x9d variety, which are suitable for use as cleansing compositions, and in particular for use as shower gels, which are formulated to give mild cleansing and optionally conditioning of the skin, and which are dispensed as a gel but generate a foam which is rich and feels luxurious to use.
Self foaming gel compositions formulated to cleanse the skin are well known. Such products may be considered superior to mousse type cleaning products, which suffer from the disadvantage that when applying a pre-formed mousse onto the skin, the mousse tends to break down and dissipate quickly, without providing substantive lather. In contrast, self-foaming compositions are dispensed initially as viscous liquids or gels, which generate copious amounts of lather as they are spread over the skin and optionally rubbed.
It is also known to formulate products which provide in particular a cleansing benefit, which are in the form of a bag in can gel composition. For example, WO 97/03646 discloses a bag in can cleansing composition which contains a base composition which has a viscosity of at least 9,500 cps, which in practice is achieved by the use of a specified thickener. The composition is said to have superior properties by virtue of the relatively high viscosity, in terms of improved stability and the ability to incorporate higher levels of volatile self foaming agent.
A variety of problems have been found to be associated with such bag in can gel compositions. A particular problem relates to the manufacture of such compositions, and especially how to dose into a bag in can arrangement a gel composition which is not so viscous so as to cause problems in the dosing of that composition, and/or to require the use of specialist equipment to dose the composition. In particular, it is clear from the teaching of WO97/03646 that the composition is required to have a minimum viscosity of 9,500 cps. As such, the composition is difficult to process and dose on conventional filling lines.
An associated problem is that in preparing surfactant based gel compositions which subsequently have a self foaming volatile component (such as a liquifiable propellant gas) dosed into them, a number of these compositions experience a drop in viscosity when the self foaming volatile component is dosed into them. This can be disadvantageous, since it is desirable that the product as dispensed has a good, relatively viscous gel structure. This in turn is so that the dispensed product will not only have good manipulation properties for the user, but also so that the relatively rigid gel structure is able to accommodate a relatively high amount of self foaming agent (e.g. liquifiable propellant gas), and to entrap it relatively well. This is so that the resulting product foams well when lathered (by virtue of the relatively high content of volatile component), but also so that it does not foam prematurely after being dispensed.
It is thought that because of the phenomena described of thinning when the propellant gas is dosed that it is necessary for the base composition to have a relatively high initial viscosity, such that any thinning of the product when propellant gas is dosed which does occur is not too deleterious to the properties of the final product as dispensed.
GB-A-2,213,160 describes a soap free post foaming gel composition comprising a major amount of water, 3-23% of a water soluble anionic alkali metal alkyl ether sulphate surfactant, 1-24% of dispersible nonionic ethoxylated fatty alcohol or fatty ester, and 5-20% saturated aliphatic hydrocarbon foaming agent, with the anionic surfactant and the ethoxylated fatty alcohol or ester being present in pre-determined ratios. Compositions according to this teaching are based on the specific combination of the anionic and nonionic surfactants, i.e. the alkyl ether sulphate and the nonionic ethoxylated fatty alcohol or fatty ester, and the criticality of each ingredient in the composition is clearly referred to.
A further problem which may be encountered relates to the stability of such cleansing compositions, especially those compositions which are based on non-soap surfactants. Regarding scap-based compositions, post foaming shaving gels employing soap based formulations are well known in the art. However, fundamentally it is desirable to create a cleansing composition based on non-soap surfactants, since by eliminating or reducing any soap to a low level the mildness of the composition may be improved. However, the inclusion of only a low level of soap means that it can be relatively difficult to structure and stabilise the cleansing composition.
We have found a way of formulating such self foaming gel or viscous liquid compositions such that they can deliver effective cleansing and optionally conditioning of the skin, are relatively easy to manufacture, and also have the desired stability and structure characteristics.
Thus, according to a first aspect of the invention, there is provided a packaged aqueous self foaming liquid cleansing composition comprising a base composition comprising a surfactant selected from anionic, nonionic, amphoteric, zwitterionic or cationic surfactants, and mixtures thereof, a hydrophobic component, and a post foaming agent, wherein the composition is substantially free of soap and thickens on the addition of the post foaming agent to the base composition.
Compositions according to the invention may conveniently be packaged in a so-called bag in can package, in which the cleansing composition is packaged inside a flexible bag, which is itself disposed in a can, with a suitable propellant gas located between the can and bag which pressurises the composition in the bag to a degree where it can be dispersed from suitable hardware.
Alternatively, the composition can be packaged in a pressurised bladder type package, in which the composition is packaged in what amounts to an elasticated bladder, which bladder maintains the contents of the bladder under positive pressure. This pressure is sufficient to cause the contents of the bladder to be dispensed via a closure mechanism located in the package.
In a highly preferred embodiment of the invention, the aqueous composition, shortly prior to being mixed with the self foaming agent, and subsequently being dosed into the product package, has a viscosity of less than 9,000 mPa.s, preferably less than 8,000 mPa.s, more preferably less than 5,000 mPa.s, and even more preferably less than 3,000 mPa.s. It is also highly preferred that packaged composition is prepared by preparing the aqueous base portion of the composition as a somewhat viscous liquid, but excluding the post foaming agent. Just prior (say within 1 minute, preferably with in 10 seconds, preferably within 1 second) to dosing the aqeuous composition into the package of the arrangement (which in the case of a bag in can package is conveniently already located within the can), the post foaming agent is dosed into the aqueous composition, which is then rapidly dosed into a suitable container, such as e.g. a bag within the dispensing package.
However, compositions according to the invention typically thicken on the addition of self foaming agent to form a viscous gel, such that the dispensed composition has good handling and sensory properties, and also such that it retains the post foaming agent well after being dispensed.
By manufacturing the composition in this manner, it is possible to make the aqueous base such that it has a relatively low viscosity, and is therefore easy to process. However, introduction of the post foaming agent into the composition just prior to dosing the composition into the container ensures that any thickening of the composition, which is desirable bearing in mind that the form of the dispensed composition is as a viscous liquid or gel, does not occur until the composition is inside the container. This method therefore simplifies the manufacturing process. Gel compositions according to the invention are not simple propellant driven compositions, and may not be dispensed from conventional propellant driven aerosol packaging, since they are too viscous to dispense from such conventional single compartment propellant driven aerosal packaging. It is also important that the packaged composition does not have any headspace, since if this were to occur it could cause the composition to be dispensed as a mousse.
Where the packaged composition utilises bag in can packaging, compositions according to the invention have two associated gases; a propellant gas and a post (self) foaming agent. The propellant gas is that which is contained within the can, but acts against the outside of the bag in which the composition is contained to dispense the composition when an actuator on the can is used. The propellant gas can be any suitable gas, but is conveniently a non-liquifiable propellant gas, such as compressed air, though any propellant which would function to dispense the composition would be suitable. The propellant gas is present in the packaged composition at any required and suitable level, but is typically present in the packaged product at levels sufficient to produce a satisfactory dispensing pressure, which will typically be 2-12 bar, more preferably 3-9 bar.
The other component required in such packaged composition according to the invention is a post foaming agent. The post foaming agent is present in compositions according to the invention to allow the composition, which is dispensed in the form of a stable gel, once dispensed to generate a foam, as it evaporates on contact with a skin surface, thereby experiencing body heat. The generation of a foam provides a product which has various desirable consumer attributes, including ease of handling and spreading, and desirable sensory properties.
Suitable post foaming agents for inclusion in compositions according to the invention are volatile or liquifiable, and include (but are not limited to) hydrocarbons, such as isobutane and isopentane. Post foaming agents are present in packaged compositions according to the invention at levels of 4-15%, more preferably 5-10% by weight of the packaged composition. Suitable post foaming agents should be capable of being contained in compositions according to the invention as liquids, which may have been formed under the pressure to which the packaged composition has been subjected. As such, it is also desirable and may even be essential that packages in which the packaged composition is stored have no head space, to prevent the premature evaporation of the post foaming agent.
Packaged compositions according to the invention contain a blend of hydrophobic components, including perfume oils and hydrophobic benefit agent components, and hydrocarbon post foaming agents, which are blended and matched, and chosen in conjunction with a suitable surfactant or blend of surfactants, in order to form a stable isotropic system. Compositions according to the invention are often microemulsions.
The hydrophobic component in the composition may conveniently be a benefit agent, a perfume oil, or another hydrophobic component. The composition according to the invention may conveniently be suitable for cleansing, and in addition optionally moisturising, conditioning or protecting the skin. Where the hydrophobic component in the composition is a benefit agent, this may be included in the composition to moisturise, condition and/or protect the skin. By xe2x80x9cbenefit agentxe2x80x9d is meant a substance that softens the skin (stratum corneum) and keeps it soft by retarding the decrease of its water content, and/or protects the skin. However, substantial deposition on the skin of a hydrophobic component or benefit agent is not necessarily a feature of compositions according to the invention.
Preferred hydrophobic components which may be solid or liquid at room temperature, but in compositions according to the invention are to be found in liquid form (either by virtue of being liquid at room temperature themselves, or by being solubilised in a hydrophobic liquid component so as to provide a liquid composition) include:
a) silicone oils, gums and modifications thereof such as linear and cyclic polydimethylsiloxanes, amino, alkyl alkylaryl and aryl silicone oils;
b) fats and oils including natural fats and oils such as jojoba, soyabean, rice bran, avocado, almod, olive, sesame, persic, castor, coconut, milk oils; cacaco fat, beef tallow, lard; hardened oils obtained by hydrogenating the aforementioned oils; and synthetic mono, di and triglycerides such as myristic acid glyceride and 2-ethylhexanoic acid glyceride;
c) waxes such as carnauba, spermaceti, beeswax, lanolin and derivatives thereof;
d) hydrophobic plant extracts;
e) hydrocarbons such as liquid paraffins, petroleum jelly, microcrystalline wax, ceresin, squalene, squalane, and mineral oil;
f) higher fatty acids such as lauric, myristic, palmitic, stearic, behenic, oleic, linoleic linolenic, lanolic, isostearic and poly unsaturated fatty acids (PUFA) acids;
g) higher alcohols such as lauryl, cetyl, steryl, oleyl, behenyl, and 2-hexadecanol alcohol;
h) esters such as cetyl octanoate, myristyl lactate, cetyl lactate, isopropyl myristate, myristyl myristate, isopropyl palmitate, isopropyl adipate, butyl stearate, decyl oleate, cholesterol isostearate, glycerol monostearate, glycerol distearate, glycerol tristearate, alkyl lactate for example lauryl lactate, alkyl citrate and alkyl tartrate;
i) essential oils such as fish oils, mentha, jasmine, camphor,white cedar, bitter orange peel, ryu,turpentine, cinnamon, bergamont, citurs unshiu, calamus, pine, lavender, bay, clove, hiba, eucalyptus, lemon, starflower, thyme, peppermint, rose, sage, menthol, cineole, eugenol, citral, citronelle, borneol, linalool, geraniol, evening primrose, camphor, thymol, spirantol, pinene, limonene and terpenoid oils;
j) lipids such as cholesterol, ceramides, sucrose esters and pseudo-ceramides as described in European Patent Specification No. 556 957;
k) vitamins such as vitamin A and E, and vitamin alkyl esters, including vitamin C alkyl esters;
l) sunscreens such as octyl methoxyl cinnamate (Parsol MCX) and butyl methoxy benzoylmethane (Parson 1789)
m) phospholipids;
n) perfume oils; and
o) mixtures of any of the foregoing components.
Particularly preferred hydrophobic benefit agents include esters such as isopropyl palmitate and myristate, and perfume oils.
The hydrophobic benefit agent is preferably present in an amount of from 0.1 to 20 wt %, more preferably 0.5 to 10%, even more preferably 0.5 to 5 wt % by weight of the composition.
The surfactant or surfactants can be selected from any known surfactant suitable for topical application to the human body, provided that they are blended in such a way as to form a stable isotropic system with the hydrophobic components of the composition. Mild surfactants, i.e. surfactants which do not damage the stratum corneum, the outer layer of skin, are particularly preferred. Because of their lathering properties, anionic surfactants are highly preferred components of compositions according to the invention. Where the composition contains an anionic surfactant, it is preferable that the composition also contains a co-surfactant, which can be a nonionic, cationic amphoteric or zwitterionic surfactant. However, compositions according to the invention are substantially soap free; that is, they contain less than about 1% by weight of soap.
A preferred anionic surfactant is alkyl ether sulphate of formula:
RO(CH2CH2O)nSO3M
where R is an alkyl group of 8 to 22 carbon atoms, n ranges from 0.5 to 10 especially from 1.5 to 8, and M is a solubilising cation.
Another preferred anionic surfactant is fatty acyl isethionate of formula:
RCO2CH2CH2SO3M
where R is an alkyl or alkenyl group of 7 to 21 carbon atoms and M is a solubilising cation such as sodium, potassium, ammonium or substituted ammonium. Preferably at least three quarters of the RCO groups have 12 to 18 carbon atoms and may be derived from coconut, palm or a coconut/palm blend.
Other possible anionic surfactants included alkyl glyceryl ether sulphates, alkyl sulphosuccinates, acyl taurates, acyl sarcosinates, alkyl sulphoacetates, alkyl phosphates, alkyl phosphate esters, acyl lactylates, acyl glutamates and mixtures thereof.
Sulphosuccinates may be monoalkyl sulphosuccinates having the formula:
R5O2CCH2CH(SO3M)CO2M;
and amido-MEA sulphosuccinates of the formula:
R5CONHCH2CH2O2CCH2CH(SO3M)CO2M; wherein R6 ranges from C8-C20 alkyl, preferably C12-C15 alkyl and M is a solubilising cation.
Sarcosinates are generally indicated by the formula: R6CON(CH3)CH2CO2M; wherein R5 ranges from C8-C20 alkyl, preferably C12-C16 alkyl and M is a solubilising cation.
Taurates are generally identified by the formula: R5CONR6CH2CH2SO3M; wherein R5 ranges from C2-C20 alkyl, preferably C12-C15 alkyl, R6 ranges from C1-C4 alkyl, and M is a solubilising cation.
Harsh surfactants such as primary alkane sulphonate or alkyl benzene sulphonate will generally be avoided.
If the surfactant comprises soap, the soap is preferably derived from materials with a C5 to C22 substantially saturated carbon chain and, preferably, is a potassium soap with a C12 to C16 carbon chain.
Suitable nonionic surfactants include alkyl polysaccharides, lactobionamides, ethyleneglycol esters, glycerol monoethers, polyhydroxyamides (glucamide), primary and secondary alcohol ethoxylates, especially the C8-C20 aliphatic alcohols ethoxylated with an average of from 1 to 20 moles of ethylene oxide per mole of alcohol. Other suitable nonionics include oil in water emulsifiers such as PEG-40 hydrogenated castor oil.
Suitable further surfactant materials are zwitterionic detergents which have an alkyl or alkenyl group of 7 to 18 carbon atoms and comply with an overall structural formula:
where R1 is alkyl or alkenyl of 7 to 18 carbon atoms R2 and R3 are each independently alkyl, hydroxyalkyl or carboxyalkyl of 1 to 3 carbon atoms;
m is 2 to 4;
n is 0 to 1;
x is alkylene of 1 to 3 carbon atoms optionally substituted with hydroxyl; and
Y is xe2x80x94CO2 or xe2x80x94SO3.
Zwitterionic surfactants within the above general formula include simple betaines of formula:
and amido betaines of formula;
where m is 2 or 3.
In both formulae R1, R2 and R3 are as defined previously.
R1 may, in particular, be a mixture of C12 and C14 alkyl groups derived from coconut so that at least half, preferably at least three quarters, of the group R1 has 10 to 14 carbon atoms. R2 and R3 are preferably methyl.
A further possibility is a sulphobetaine of formula:
where m is 2 or 3, or variants of these in which xe2x80x94(CH2)3SO3xe2x88x92 is replaced by
R1, R2 and R3 in these formulae are as defined previously.
Mixtures of any of the foregoing surfactants may also be used.
The surfactants is preferably present at a level of from 10 to 35 wt %, preferably 12 to 30 wt % of the composition.
An optional component in compositions according to the invention is a cationic polymer, such as for example cationic celluloses.
Cationic cellulose is available from Amerchol Corp. (Edison, N.J., USA) in their Polymer JR (trade mark) and LR (trade mark) series of polymers, as salts of hydroxyethyl cellulose reacted with trimethyl ammonium substituted epoxide, referred to in the industry (CTFA) as Polyquaternium 10. Another type of cationic cellulose includes the polymeric quaternary ammonium salts of hydroxyethyl cellulose reacted with lauryl dimethyl ammonium-substituted epoxide, referred to in the industry (CTFA) as Polyquaternium 24. These materials are available from Amerchol Corp. (Edison, N.J., USA) under the tradename Polymer LM-200.
A particularly suitable type of cationic polysaccharide polymer that can be used is a cationic guar gum derivative, such as guar hydroxypropyltrimonium chloride (Commercially available from Rhone-Poulenc in their JAGUAR trademark series).
Examples are JAGUAR C13S, which has a low degree of substitution of the cationic groups and high viscosity, JAGUAR C15, having a moderate degree of substitution and a low viscosity, JAGUAR C17 (high degree of substitution, high viscosity), JAGUAR C16, which is a hydroxypropylated cationic guar derivative containing a low level of substituent groups as well as cationic quaternary ammonium groups, and JAGUAR 162 which is a high transparency, medium viscosity guar having a low degree of substitution.
Preferably the cationic polymer is selected from cationic cellulose and cationic guar derivatives. Particularly preferred cationic polymers are JAGUAR C13S, JAGUAR C15, JAGUAR C17 and JAGUAR C16 and JAGUAR C162, especially Jaguar C13S.
Cationic polymer if present in compositions according to the invention is present at levels of 0.01-1.2%, more preferably 0.05-1.0%, even more preferably 0.1-0.5% by weight of the composition.
In some embodiments an auxiliary structurant or thickener may be added to the composition. Suitable structurant material include swelling clays, for example laponite; cross-linked polyacrylates such as Carbopol (TM) (polymers available from Goodrich); actylates and copolymers thereof; polyvinylpyrrolidone and copolymers thereof; polyethylene imines; polymeric carboxylates, consisting of and including modified and unmodified starches, unsubstituted guar gums, agars, alginates, xanthan gum, carrageenan, cellulose derivatives, exudate gum, gellan gum, gelatin, pectins and seed gums; gellants; and mixtures thereof.
Preferred thickeners for the composition include fumed silica; alkyl silicone waxes; aluminum silicate; fatty acids and derivatives thereof, in particular, fatty acid monoglyceride polyglycol ethers; polyammonium stearate; hydrotalcites; and mixtures thereof. A particularly preferred thickener is PEG-120 methyl glucose dioleate.
The composition may also comprise a viscosity modifying agent, ie a material which adjusts the viscosity of the composition to be that which is suitable for and preferred by consumers. Suitable materials include ethylene glycols, propylene glycols, salts such as sodium chloride and ammonium sulphate; and sucrose esters.
Further examples of structurants and thickeners are given in the International Cosmetic Ingredient Dictionary, Seventh Edition, 1997, published by CTFA (The Cosmetic, Toiletry and Fragrance Association), incorporated herein by reference.
Compositions of the invention may be formulated as propellant driven and dispensed products for washing the skin, for example, bath or shower gels, hand washing compositions or facial washing liquids, and products for washing the hair, as well as post foaming shaving gels. Shower gels, and also post foaming shaving gels are particularly preferred product forms.
Other typical optional components of such compositions include opacifiers, preferably at 0.2 to 2.0 wt %; preservatives, preferably at 0.2 to 2.0 wt %; pH adjusters, typically at 0.05-2.0 wt %; colourants, preferably at 0.05-2.0 wt %; biological extracts, preferably at 0.05-2.0 wt %; humectants, such as glycerol or sorbitol, preferably at 0.1-10.0 wt %; and perfumes, preferably at 0.5 to 2.0 wt %.
The invention will be further illustrated by reference to the following non-limiting examples.

Unilever Home and Personal Care USA, division of Conopco, Inc.


The present invention is a modular stock system for rifles. The system replaces the rifle""s buffer tube with a modified one containing a mount for a constant cheek weld and a rail track for adjustment. A hind portion then mounts on the replacement buffer tube. The hind portion is interchangeable depending on the user""s needs. Various configurations of the hind portion are discussed, including adjustable stocks, fixed stocks, and specialized stocks. The hind portion may be made even further modular by the addition of rail system.

The present invention relates to a rifle stock and more particularly related to a modular gunstock that provides a constant surface for a uniform cheek weld and the option of a variable length feature.
Adjustable gunstocks are known in the prior art. For example, U.S. Pat. No. 4,735,007 to Gal (1988); U.S. Pat. No. 4,327,626 to McQueen (1982); U.S. Pat. No. 3,442,042 to Gilbert (1967); U.S. Pat. No. 3,348,328 to Roy (1966); U.S. Pat. No. 3,267,601 to Roy (1964); 3,137,958 to Lewis, et al. (1962); U.S. Pat. No. 5,827,992 to Harris, et al. (1998) and U.S. Pat. No. 2,900,877 to McClenahan (1956) are all illustrative of the prior art.
The current standard in automatic and semi-automatic rifles is to have a stock capable of receiving and covering a recoil absorption appendage, or xe2x80x9cbuffer tubexe2x80x9d, shown in the ""992 and ""877 patents. The most popular of the available adjustable stocks follow in form to the ""328 patent, which is to say they use a spring loaded latch to bias a pin inside a provided adjustment hole. When a user wishes to adjust the stock, a simple compression of the spring/latch assembly is all that is required to release the pin and, therefore, adjust the stock. The ""626 patent operates with a tooth-and-groove assembly which, otherwise, follows the same principles. In both cases, compression of the spring is necessary for adjustment in both directions along any length beyond the proximate hole/groove. All of the adjustable stocks may have their butt portion removed, though they are not designed to have such a feature repeatedly used, much less have additional stock modules to exchange. In those cases where the stock moves longitudinally along the weapon, with no other motion relative to the weapon, the user must make some sacrifice as to one, if not both, of two features. The user either loses constant and uniform cheek weld to the weapon or stock stability. The lack of uniform cheek weld can interfere with comfortable and precise use of the weapon. Stock stability can also interfere with precise weapon use.
While the aforementioned inventions accomplish their individual objectives, they do not describe a truly modular stock, namely a stock where the butt portion is designed to be changed at the whim or need of the user. Likewise, they do not describe a stock that utilizes a cam/tension lock that enables the user to have not only a controlled extension, but also an unrestricted and silent compression and extension of the stock. None of the disclosed stocks have an adjustable preset lock to use in conjunction with an unrestricted adjustment. Finally, none of the disclosed stocks present a surface for a constant cheek weld while simultaneously having a sturdy, longitudal adjustment capable stock, much less a uniform cheek weld with different stock types. In this respect, the gunstock according to the present invention departs substantially from the usual designs in the prior art. In doing so, this invention provides a modular gunstock allowing for a uniform and identical cheek weld for different stock modules, even while simultaneously adjusting the stock length of an adjustable stock.
In view of the foregoing disadvantages inherent in the known types of gunstocks, this invention provides an improved gunstock. As such, the present invention""s general purpose is to provide a new and improved modular gunstock that will have multiple functionality, dependent upon chosen stock modules. The invention will provide simultaneous adjustment of the stock while providing a sturdy, uniform cheek weld on the stock when used with an adjustable stock module. The invention will also provide an identical cheek weld surface with a sturdy stock if a fixed stock is used.
To provide the improved feature, the gunstock comprises both a fore and butt portion. The fore portion consists of a buffer tube attachable to the weapon""s receiver and a check plate extension essentially parallel to the buffer tube. Located on the underside of the buffer tube is a rail track. The rear portion consists of a receiving cylinder of sufficient length and width to receive the buffer tube of the fore portion. Located on the lower rim of the cylinder is the compression latching mechanism, designed to interface with the rail track. Rearward of the receiving cylinder is the stock butt and any other accessories as required by the user. In the preferred embodiment, the cheek plate is fused to the buffer tube, presenting a wider rest for a user""s cheek, and the rear portion comprises a receiving cradle, or semi-cylinder, which interfaces along a pair of attachment grooves located on either side of the buffer tube, having a distal relation with the cheek plate.
The more important features of the invention have thus been outlined in order that the more detailed description that follows may be better understood and in order that the present contribution to the art may better be appreciated. Additional features of the invention will be described hereinafter and will form the subject matter of the claims that follow.
Many objects of this invention will appear from the following description and appended claims, reference being made to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.
Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.


Signal processors for permitting the transparent, simultaneous transmission and reception of a secondary data signal with a video signal in the video band is disclosed. The signal processor in the transmitter rasterizes the data at the horizontal scanning rate and modulates the data with a data carrier at a non-integral multiple of the horizontal scanning rate to obtain frequency interleaving. The data is transmitted during the active video portion of each video line.

1. Field of the Invention
This invention relates to transmitting two signals on one communication channel and more particularly transmitting data during the active video portion of a video signal.
2. Description of the Prior Art
Several techniques have been developed to allow the transmission of two signals on the same communications channel. When the communications channel is a specified bandwidth of the spectra, these methods include time division multiplexing, transmitting orthogonally polarized waves, transmitting by two transparent methods, each transparent to the other and frequency interleaving.
In the case of video signals, such as NTSC and PAL signals, several different methods have been used for transmission of additional information in the band. For example, a chrominance (color) signal is transmitted by frequency interleaving the chrominance signal with the luminance (black and white) signal. In particular, for the NTSC standard, the luminance signal and the chrominance signals are frequency interleaved. Of course, the chrominance signals are closely related to the luminance signal and the signals exhibit a high degree of correlation.
There are also intervals where no picture information is being transmitted such as during the vertical and horizontal blanking intervals. In some systems, for example close captioned television for the heating impaired, the close captioned information is transmitted during the vertical blanking intervals. Of course, the data rate of transmission systems using the blanking period is relatively low, typically about 20,000 bits per second. Although such transmission rates may be suitable for close caption television, this is far too low for the suitable transmission of large volumes of information such as the 1.544 megabits per second for T1 transmission.
Therefore, it is a first object of this invention to permit transmission at a higher data rate than those permitted during the blanking period. It is a second object of this invention to permit transmission at the higher data rate without causing any noticeable interference from the transmitted information to conventional television receivers. It is yet a third object of this invention to achieve such transmission using frequency interleaving.

System for transparent transmission and reception of a secondary data signal with a video signal in the video band


A low temperature chemical vapor deposition process comprising heating in a chemical vapor depositon reactor a substrate upon which deposition is desired to a temperature of from about 550.degree. C. to about 750.degree. C. in a chemical vapor deposition reactor having a pressure of from about 0.1 torr to approximately atmospheric pressure, introducing into the reactor a silicon-containing feed and optionally an oxygen containing feed, said silicon containing feed consisting essentially of one or more compounds having the general formula ##STR1## wherein: R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are hydrogen, azido or C-2 to C-6 alkyl, aryl or C-7 to C-10 aralkyl groups, at least one but not more than three of R.sub.1, R.sub.2, R.sub.3 and R.sub.4, being azido, and maintaining the temperature and pressure to cause a film of silicon nitride, silicon oxynitride or silicon dioxide to deposit is disclosed.

The general principles underlying the formation of thin films are described in HANDBOOK OF THIN FILM TECHNOLOGY, Maissell, Leon I. and Glang, Reinhard, editors, McGraw Hill Book Company, New York, 1970, and the general technology for processing silicon-based semiconductor devices in described in SILICON PROCESSING FOR THE VLSI ERA, Wolf, Stanley, and Talbert, Richard N., eidtors, Lattice Press, Sunset Beach, Calif., 1986, which includes a discussion of thin film technology.
The chemistry of silanes is described by Arkles, B., Peterson, W. R., Jr., KIRK-OTHMER ENCYCLOPEDIA OF CHEMICAL TECHNOLOGY. 3rd ed. Vol 20. 887-911. Silanes, also referred to as silicon hydrides, are compounds containing a hydrogen-silicon bond. Compounds which include only silicon-carbon bonds, i.e. where all hydrogens have been replaced by alkyl, aryl or aralkyl substituents are also referred to occasionally, and herein, as silanes.
The properties of organosilanes are determined largely by the properties of the silicon atom which is larger than the carbon atom, enabling nucleophilic attack on the silicon to occur more readily than on carbon. Electrophilic attack on hydrogen bonded to silicon is also facilitated by the small steric constraints of hydrogen and the increased bond length for Si--H. In addition to the increased bond length, the Si--H bond energy is considerably lower than C--H and is reflected in the thermal stabilities of such bonds. Organohydrosilanes begin to decompose at 440.degree.-460.degree. C. through homolytic cleavage of the Si--H bond and subsequent radical formation.
Organohydrosilanes undergo a wide variety of chemical conversions. The Si--H bond of organohydrosilanes reacts with elements of most groups of the periodic system. Organosilanes, the simplest of which is methylsilane, are stable to air. The larger-chain alkylsilanes are more stable but ignite spontaneously when vaporized in oxygen under pressure. Phenyl and cyclohexylsilane can be distilled open to the atmosphere. Trialkyl- and triarylsilanes are more stable and have been distilled at as much as 325.degree. C. without decomposition.
Alkylation and arylation of organosilanes occur readily with alkyl and aryl alkalimetal compounds with good yields, especially in tetrahydrofuran and ethyl ether according to the general reaction: EQU R.sub.n SiH.sub.4-n +(4-n)R'M>.fwdarw.R.sub.n SiR'.sub.4-n +(4-n)MH
where R and R' are alkyl, aryl or aralkyl and M is Li, Na, or K and n=1 to 4.
A large variety of "thin films" are used in the fabrication of Very Large Scale Integration (VLSI) devices. These films may be thermally grown or deposited from the vapor phase. They can be metals, semiconductors, or insulators.
Thin films for use in VLSI fabrication must satisfy a large set of rigorous chemical, structural, and electrical requirements. Film composition and thickness must be strictly controlled to facilitate etching of submicron features. Very low densities of both particulate defects and film imperfections, such as pinholes, become critical for the small linewidths, high densities, and large areas necessary for VLSI. These small geometries also create highly rugged topography for overlying films to cover. Therefore, excellent adhesion, low stress, and conformal step coverage are required of a VLSI thin film, and its own surface topography should reduce or even planarize the underlying steps if possible.
Although the properties of a bulk material may be well characterized, the same material in its thin film form may have properties substantially different from those of the bulk. One reason is that thin film properties are strongly influenced by surface properties, while in bulk materials this is not the case. The thin film, by its very definition has a substantially higher surface-to-volume ratio than does a bulk material. The structure of thin films, and their method of preparation also play a vital role in determining the film properties.
The formation of such films is accomplished by a large variety of techniques, but which can conceptually be divided into two groups: (1) film growth by interaction of a vapor-deposited species with the substrate; and (2) film formation by deposition without causing changes to the substrate material.
Chemical vapor deposition, or CVD, in which solid films are formed on a substrate by the chemical reaction of vapor phase chemicals that contain the required constituents; (b) physical vapor deposition, or PVD, in which the species of the thin film are physically dislodged from a source to form a vapor which is transported across a reduced pressure region to the substrate, where it condenses to form the thin film; and (c) coating of the substrate with a liquid, which is then dried to form the solid thin film. When CVD process are used to form single-crystal thin films, the process is termed epitaxy. The formation of thin films by PVD includes the processes of sputtering and evaporation.
Thin film generally have smaller grain size than do bulk materials. Grain size is a function of the deposition conditions and annealing temperatures. Larger grains are observed for increased film thickness, with the effect increasing with increasing substrate or deposition temperature. The initial deposition temperature plays an important role in determining the final grain size. The dependence on deposition rate is due to the fact that even if clusters have high mobility, at high deposition rate they are quickly buried under subsequent layers. For very high deposition rates, the heat of condensation can raise the substrate temperature, thereby producing increased grain size from thermal effects.
The surface roughness of films occurs as a result of the randomness of the deposition process. Real films almost always show surface roughness, even though this represents a higher energy state than that of a perfectly flat film. Depositions at high temperatures tend to show less surface roughness. This is because increased surface mobility from the higher substrate temperatures can lead to filling of the peaks and valleys. On the other hand, higher temperatures can also lead to the development of crystal facets, which may continue to grow in favored directions, leading the increased surface roughness. At low temperatures the surface roughness as measured by surface area, tends to increase with increased film thickness. Oblique deposition which results in shadowing, also increases surface roughness. Epitaxial and amorphous deposits have shown measured surface area nearly equal to the geometrical area, implying the existence of very flat films. This has been confirmed by Scanning Electron Micrography (SEM) examination of these films. Surface roughness has also been observed to increase as a result of the presence of contamination on the substrate or in the vapor phase during deposition.
The density of a thin film provides information about its physical structure. Density is usually determined by weighing the film and measuring its volume. If a film is porous from the deposition process, it generally has a lower density than bulk material.
The single crystal substrate is the dominant factor in epitaxy. Some crystal symmetry must exist between the deposit and the substrate, and the lattice parameters of each material must be close to the same value. The lattice misfit, which is the percentage difference between the lattice constant of the deposit and that of the substrate plane in contact, must be small to achieve epitaxy. The deposition temperature also plays a role in epitaxy. Elevated temperatures increase the propensity for epitaxial growth. This is engendered by several mechanism, including: cleaner surfaces; decreased supersaturation; and increased adatom energy.
The deposition rate also plays a role in epitaxy. Lower rates tend toward epitaxy, while higher deposition rates lead to polycrystalline or amorphous deposition. Three growth regimes are observed for the deposition of Si on a clean Si substrate: (a) at low temperature and high deposition rates the deposits are amorphous; (b) at high substrate temperatures and low rate deposition they tend to be single crystal; and (c) at intermediate conditions polycrystalline films tend to form.
Nearly all films are found to be in a state of internal stress, regardless of the means by which they have been produced. The stress may be compressive or tensile. Compressively stressed films would like to expand parallel to the substrate surface, and in the extreme, films in compressive stress will buckle up on the substrate. Films in tensile stress, on the other hand, would like to contract parallel to the substrate, and may crack if their elastic limits are exceeded. In general, the stresses in thin films are in the range of 10.sup.8 -5.times.10.sup.10 dynes/cm.sup.2. Highly stressed films are generally undesirable for VLSI applications for several reasons, including: (a) they are more likely to exhibit poor adhesion; (b) they are more susceptible to corrosion; (c) brittle films, such as inorganic dielectrics, may undergo cracking in tensile stress; and (d) the resistivity of stressed metallic films is higher than that of their annealed counterparts.
The intrinsic stress reflects the film structure in ways not yet completely understood. It has been observed that the intrinsic stress in a film depends on thickness, deposition rate, deposition temperature, ambient pressure, method of film preparation, and type of substrate used, among other parameters.
At low substrate temperatures, metal films tend to exhibit tensile stress. This decreases with increasing substrate temperature, often in a linear manner, finally going through zero or even becoming compressive. The changeover to compressive stress occurs at lower temperatures for lower melting point metals.
The effect of deposition rate on film stress is ambigous. The film stress starts out tensile, decreases as the power increases, and finally becomes compressive with further power increase.
A Chemical Vapor Deposition (CVD) process can be summarized as consisting of the following sequence of steps: (a) a given composition and flow rate of reactant gases and diluent inert gases is introduced into a reaction chamber; (b) the gas species move to the substrate; (c) the reactants are absorbed on the substrate; (d) the adatoms undergo migration and film-forming chemical reactions, and (e) the gaseous by-products of the reaction are desorbed and removed from the reaction chamber. Energy to drive the reactions can be supplied by several methods, e.g. thermal, photons, or electrons, with thermal energy being the most commonly used.
In practice, the chemical reactions of the reactant gases leading to the formation of a solid material may take place not only on or very close to the wafer surface, a heterogeneous reaction, but also in the gas phase, a homogeneous reaction. Heterogeneous reactions are much more desirable, as such reactions occur selectively only on heated surfaces, and produce good quality films. Homogeneous reactions, on the other hand, are undesirable, as they form gas phase clusters of the depositing material, which can result in poorly adhering, low density films, or defects in the depositing film. In addition, such reactions also consume reactants and can cause decreases in deposition rates. Thus, one important characteristic of a chemical reaction for CVD application is the degree to which heterogeneous reactions are favored over gas phase reactions.
Since the aforementioned steps of a CVD process are sequential, the one which occurs at the slowest rate will determine the rate of deposition. The steps can be grouped into (1) gas-phase processes, and (2) surface processes. The gas phase phenomenon of interest is the rate at which gases impinge on the substrate. This is modeled by the rate at which gases cross the boundary layer that separates the bulk regions of flowing gas and substrate surface. Such transport processes occur by gas-phase diffusion, which is proportional to the diffusivity of the gas, D, and concentration gradient across the boundary layer. The rate of mass transport is only relatively weakly influenced by temperature.
Several surface processes can be important once the gases arrive at the hot substrate surface, but the surface reaction, in general, can be modeled by a thermally activated phenomenon which proceeds at a rate which is a function of the frequency factor, the activation energy, and the temperature. The surface reaction rate increases with increasing temperature. For a given surface reaction, the temperature may rise high enough so that the reaction rate exceeds the rate at which reactant species arrive at the surface. In such cases, the reaction cannot proceed any more rapidly than the rate at which reactant gases are supplied to the substrate by mass transport, no matter how high the temperature is increased. This situation is referred to as a mass-transport limited deposition process.
On the other hand, at lower temperatures, the surface reaction rate is reduced, and eventually the arrival rate of reactants exceeds the rate at which they are consumed by the surface reaction process. Under such conditions the deposition rate is reaction rate limited. Thus, at high temperatures, the deposition is usually mass-transport limited, while at lower temperatures it is surface-reaction rate-limited. In actual processes the temperature at which the deposition condition moves from one of these growth regimes to the other is dependent on the activation energy of the reaction, and the gas flow conditions in the reactor. Thus, it is impossible to extrapolate with any certainty or accuracy date or process conditions or results from one pressure regime or temperature regime to another.
In processes that are run under reaction rate-limited conditions, the temperature of the process is an important parameter. That is, uniform deposition rates throughout a reactor require conditions that maintain a constant reaction rate. This in turn implies that a constant temperature must also exist everywhere at all wafer surfaces. On the other hand, under such conditions the rate at which reactant species arrive at the surface is not as important, since their concentration does not limit the growth rate. Thus, it is not as critical that a reactor be designed to supply an equal flux of reactants to all locations of a wafer surface. It will be seen that in low-pressure CVD (LPCVD) reactors, wafers can be stacked vertically and at very close spacing because such systems operate in a reaction rate limited mode. The reason for this is as follows:
Under the low pressure of an LPCVD reactor.about.1 torr the diffusivity of the gas species is increased by a factor of 1000 over that at atmospheric pressure, and this is only partially offset by the fact that the boundary layer, the distance across which the reactants must diffuse, increases by less than the square root of the pressure. The net effect is that there is more than an order of magnitude increase in the transport of reactants to and by-products away from the substrate surface, and the rate-limiting step is thus the surface reaction.
In deposition processes that are mass-transport limited, however, the temperature control is not nearly as critical. As mentioned earlier, the mass transport process which limits the growth rate is only weakly dependent on temperature. On the other hand, it is very important that the same concentration of reactants be present in the bulk gas regions adjacent to all locations of a wafer, as the arrival rate is directly proportional to the concentration in the bulk gas. Thus, to insure films of uniform thickness across a wafer, reactors which are operated in the mass transport limited regime must be designed so that all locations of wafer surfaces and all wafers in a run are supplied with an equal flux of reactant species. Atmospheric pressure reactors that deposit SiO.sub.2 at .about.400.degree. C. operate in the mass-transport limited regime. The most widely used APCVD reactor designs provide a uniform supply of reactants by horizontally positioning the wafer and moving them under a gas stream.
Low pressure chemical vapor deposition (LPCVD) in some cases is able to overcome the uniformity, step coverage, and particulate contamination limitations of early APCVD systems. By operating at medium vacuum, 30-250 Pa or 0.25-2.0 torr, and higher temperatures, 550.degree.-600.degree. C., LPCVD reactors typically deposit films in the reaction rate limited regime. At reduced pressure the diffusivity of the reactant gas molecules is sufficiently increased so that mass-transfer to the substrate no longer limits the growth rate. The surface reaction rate is very sensitive to temperature, but precise temperature control is relatively easy to achieve. The elimination of mass-transfer constraints on reactor design allows the reactor to be optimized for high wafer capacity. Low pressure operation also decreases gas phase reactions, making LPCVD films less subject to particulate contamination. LPCVD is used for depositing many types of films, including poly-Si, Si.sub.3 N.sub.4, SiO.sub.2, PSG, BPSG, and W.
The two main disadvantages of LPCVD are the relatively low deposition rates, and the relatively high operating temperatures. Attempting to increase deposition rates by increasing the reactant partial pressures, tends to initiate gas phase reactions. Attempting to operate at lower temperatures, results in unacceptably slow film deposition. One of the features of the present invention is the discovery that by using selected deposition source reagents, rather than methyl-containing reagents and the like which have been traditional, greatly increased deposition rates can be accomplished without the deleterious reactions and poor results which have plagued the industry for so many years.
LPCVD reactors are designed in two primary configurations: (a) horizontal tube reactors; and (b) vertical flow isothermal reactors.
Horizontal tube, hot wall reactors are the most widely used LPCVD reactors in VLSI processing. They are employed for depositing poly-Si, silicon nitride, and undoped and doped SiO.sub.2 films. They find such broad applicability primarily because of their superior economy, throughput, uniformity, and ability to accommodate large diameter, e.g. 150 mm wafers. Their main disadvantages are susceptibility to particulate contamination and low deposition rates.
The vertical flow isothermal LPCVD reactor further extends the distributed gas feed technique, so that each wafer receives an identical supply of fresh reactants. Wafers are again stacked side by side, but are placed in perforated-quartz cages. The cages are positioned beneath long, perforated, quartz reaction-gas injector tubes, one tube for each reactant gas. Gas flows vertically from the injector tubes, through the cage perforations, past the wafers, parallel to the wafer surface and into exhaust slots below the cage. The size, number, and location of cage perforations are used to control the flow of reactant gases to the wafer surfaces. By properly optimizing cage perforation design, each wafer can be supplied with identical quantities of fresh reactants from the vertically adjacent injector tubes. Thus, this design can avoid the wafer-to-wafer reactant depletion effects of the end-feed tube reactors, requires no temperature ramping, produces highly uniform depositions, and reportedly achieves low particulate contamination.
The third and last of the major CVD deposition methods is categorized not only by pressure regime, but also by its method of energy input. Rather than relying solely on thermal energy to initiate and sustain chemical reactions, plasma enhanced CVD, or PECVD uses an rf-induced glow discharge to transfer energy into the reactant gases, allowing the substrate to remain at a lower temperature than in APCVD or LPCVD processes. Lower substrate temperature is the major advantage of PECVD, and in fact, PECVD provides a method of depositing films on substrates that do not have the thermal stability to accept coating by other methods, the most important being the formation of silicon nitride and SiO.sub.2 over metals. In addition, PECVD can enhance the deposition rate when compared to thermal reactions alone, and produce films of unique compositions and properties. Desirable properties such as good adhesion, low pinhole density, good step coverage, adequate electrical properties, and compatibility with fine-line pattern transfer processes, have led to application of these films in VLSI.
The plasma, which is defined as a partially ionized gas containing an equal number of positive and negative charges, as well as some other number of non-ionized gas particles, is generated by the application of a radio frequency field to a low pressure gas, thereby creating free electrons within the discharge region. The electrons gain sufficient energy from the electric field so that when they collide with gas molecules, gas-phase dissociation and ionization of the reactant gases, e.g. silane and nitrogen or oxygen-containing species then occurs.
The energetic particles used to strike target materials to be sputtered in VLSI sputter deposition systems are generated by glow-discharges. A glow-discharge is a self-sustaining type of plasma.
The energetic species are then adsorbed on the film surface. The radicals tend to have high sticking coefficients, and also appear to migrate easily along the surface after adsorption. These two factors can lead to excellent film conformality. Upon being adsorbed on the substrate, they are subjected to ion and electron bombardment, rearrangements, reactions with other adsorbed species, new bond formations and film formation and growth. Adatom rearrangement includes the diffusion of the adsorbed atoms onto stable sites and concurrent desorption of reaction products. Desorption rates are dependent on substrate temperature, and higher temperatures produce films with fewer entrapped by-products. Gas-phase nucleation should be avoided to reduce particulate contamination.
The fact that the radicals formed in the plasma discharge are highly reactive presents some options, as well as some problems, to the process engineer. PECVD films, in general, are not stoichiometric because the deposition reactions are so varied and complicated. Moreover, by-products and incidental species are incorporated into the resultant films, especially hydrogen, nitrogen, and oxygen, in addition to the desired products. Excessive incorporation of these contaminants may lead to outgassing and concomitant bubbling, cracking, or peeling during later thermal cycling, and to threshold shifts in MOS circuits.
A plasma process requires control and optimization of several deposition parameters besides those of an LPCVD process, including rf power density, frequency, and duty cycle. The deposition process is dependent in a very complex and interdependent way on these parameters, as well as on the usual parameters of gas composition, flow rates, temperature, and pressure. Furthermore, as with LPCVD, the PECVD method is surface reaction limited, and adequate substrate temperature control is thus necessary to ensure film thickness uniformity.
Three types of PECVD reactors are available: (1) the parallel plate type; (2) the horizontal tube type; and (3) the single wafer type. It should be noted that with one major exception, the discussion on glow discharges, rf diode sputtering, and rf generated plasmas for dry etching applies to the production of rf generated plasma in PECVD reactors.
Many treatises, texts and a massive volume of technical journal literature describe in more detail the background of the technology in which this invention lies; see, for example, Thomas, HANDBOOK OF TRANSISTORS, SEMICONDUCTORS, INSTRUMENTS AND MICROELECTRONICS, Prentice Hall, Englewood Cliffs, N.J. 1968.
Nelson, U.S. Pat. No. 4,158,717 reviews the state of the art of producing silicon nitride films and describes the production silicon nitride films as protective and anti-reflective coatings and for masking semiconductive devices by a plasma discharge in azidotrimethylsilane, (CH.sub.3).sub.3 SiN.sub.3, pointing out that azidotrimethylsilane is easier to handle than silane.
Matsuda et al, U.S. Pat. No. 4,569,855, discloses the use of azidosilanes in a very low temperature (50.degree.-150.degree. C.) high energy light activated gas deposition process for forming silicon and doped silicon films. While reference is made to alkyl, aryl and alkoxy azidosilanes, there is no specific disclosure of the use of ethyl, propyl, or butyl azidosilanes, or to higher-carbon alkyl, aryl or alkoxy azidosilanes in the Matsuda et al patent. Matsuda et al speculate that thermal energy deposition of SiH.sub.4 or Si.sub.2 H.sub.6 result in Si films with poor characteristics, and teach that this difficulty can be overcome using high energy activation, i.e. photoactivation, for decomposing the gas to form a film. One would predict from Matsuda et al that thermalactivation method at higher temperatures would not be suitable for forming Si films.

Method for deposition of silicon films from azidosilane sources


A cooking rack for deep frying which includes a base, such as one formed of a plurality of spoke extensions, and a plurality of prongs extending up from the base. The rack further includes a lifting extension which is supported by the base such as by way of one or more foot extensions extending from a vertical main bar to the base. The lifting extension extends up from the base at a location that is radially spaced from a center of the base and preferably has a grasping loop. An embodiment of the invention features protrusions provided on the prongs for differentiating tipper and lower prong food positions and an additional embodiment features a grill that can be slid down into a resting position on the protrusions and with or essentially with a no horizontal slide (less than an inch horizontal slide capability). An embodiment also features a second grill which forms or is connected to the base, which base preferably features spoke extensions either radially extending from a central region of the base or represented by overlapping diametrical elongated base bars having the prongs integrally (e.g., an upward bend to form a prong from a horizontal base extension) related to the base extensions. A cooking apparatus with the rack and a cooking container and a grasping hook is also featured as well as a method of providing a cooking apparatus.

The present invention is directed at a rack device particularly well suited for outdoor deep frying of meat, poultry, fish or other deep fryable food products. For example, the invention is well suited for deep frying of a plurality of cuts of meat such as steaks or pork chops, deep frying smaller poultry items such as Cornish Hens, deep frying seafood such as fish filets, or deep frying vegetables or the like. The present invention is also directed at a frying apparatus which includes a deep fry container(s) and the rack device in combination as well as a method of using the rack device and the frying apparatus with the rack device.
The present invention is directed at a frying apparatus which comprises a rack device that is particularly well suited for the deep frying of more than one meat, poultry, fish item or similarly sized food item in oil or the like at the same time. Further the present invention is directed at a frying apparatus that features a rack device that provides for deep frying a variety of items while maintaining desired relative spacing both amongst the items being cooked and the container of the frying apparatus which receives the rack device (preferably a deep fry basket which is received in a deep fry pot which receives the oil or directly in the deep fry pot). One preferred embodiment of the rack device of the present invention is in the form of a two grill rack device assembly (preferably each grill being comprised of round wire grill with each having crossing food supports, such as horizontal, parallel crossing wires) and a food support rack. The food support rack is preferably releasably or fixedly attached or positioned relative to a first (preferably lower in use) grill such that a plurality of food support prongs of the food support rack extend up away from the first grill. In a preferred embodiment the food support rack is supported or attached to the lower grill (e.g., welded to the crossing supports thereof). While a preferred embodiment features a rack support with its own base section, the lower grill can also provide, in and of itself, the base for the food support rack.
The food support rack has prongs that have a vertical extension component (preferably vertical, e.g. a vertical rise extension greater than its run extension or a true vertical, transverse to the supporting grill relationship) onto which a meat, poultry, fish or other food product can be fastened or skewered onto each prong. Each prong preferably has an intermediate protrusion such as an integral curved bend that curves out away from the main axis of the prong and preferably toward the periphery of the device. This intermediate protrusion can function both as a food blockage member and food support member when desired (e.g., slipping a first steak cut past and below the protrusion by way of extra force application and letting a second steak cut rest on or, more preferably, above the limiting upper surface of the protrusion) and also serves to support the upper grill when an upper grill is used (e.g., passing the prongs through openings in the grill and threading the grill down into supporting contact with the protrusions which are preferably equally located in a common intermediate area of the prongs such as a 25% to 75% range of the total height of the prong. The lower grill and/or fluid support rack also has a lifting extension which is attached radially outward of a central axis of the food support rack and preferably radially outward of a periphery contacting each of the prongs. For example, the lifting extension is preferably positioned radially within an annular ring formed between the periphery contacting each of the prongs and the grill""s outer ring or even more radially external to the outer ring of the grill rack (e.g. the annular ring representing the 50% to 100% radius range of the grill and 100% to 135% representing the outward of the grill ring radius range) with the food support rack preferably being connected or made as one unit with the lower grill. The lifting extension is preferably external to the periphery defined by the prongs which are preferably three or more in number with four equally spaced prongs being preferred. The lifting extension is provided to provide a grasping component with which the rack device can be pulled out from a container and is of a sufficient height to clear, for example, the upper level of a body of oil in a cooking pot. Preferably the lifting extension is in the form of a vertical bar that has a loop portion at its free end (to facilitate lifting hook engagement) and a wing extension that is positioned intermediate of the lifting extension. The wing extension is preferably positioned on the lifting section at a common intermediate position as the above noted prong protrusion such that it functions as an underlying grill support member with the protrusion thereby stabilizing the upper grill when utilized with the rack or for added direct food support such as an end of steak support in association with two prongs through a steak cut. With this arrangement the lifting extension is preferably positioned within 5% outward and 25% inward of the radius of the outer grill ring so as to enable the wing extensions to be positioned for contact with either food cuts or an upper grill. The wing extension preferably comprises a bar or bars extending to opposite sides of the lifting extension so as to contact the upper grill to opposite sides of the lifting extension.
In a preferred embodiment, the upper grill additionally has a round centrally located ring which contacts the curve bend portions on the prongs of the food support rack (e.g., the inner ring has a circumference which matches that defined by the protrusions upper support surface). In a preferred embodiment the protrusions extend radially outward relative to the prongs such that the grill ring passes externally around the prongs. This arrangement places the prongs in contact with the interior of the ring so as to provide a stable arrangement with no horizontal sliding (due to prong/ring contact in a horizontal plane) and no vertical sliding due to the protrusion/ring engagement (preferably with the assistance of the wing extension underlying support). An alternate arrangement features the prongs arranged to have a greater circumference (but still a sliding arrangement) relative to the inner ring for horizontal stabilization in which case inwardly extending protrusions can be provided. Alternatively, an arrangement can be made wherein rather than an inner ring, the protrusion can contact linear section of the upper grill (e.g. the main grill bars or linear, transverse stabilizer bars.
The device is particularly suited for deep frying meat products outdoors in conjunction with an outdoor gas burner which supports a deep fry pot and depending on its size an additional deep-fry basket may be utilized as part of the frying apparatus or kit to support the rack device at a level above or on the floor of the pot. In a preferred embodiment the rack device is permanently fixed to a lower grill and the use of the upper grill is optional depending upon the intended use. For example, if there is a desire to deep fry steaks and/or chops the bottom rack can be utilized to support one or more steaks (with the steaks contacting or more preferably lifted, slightly above the lower grill""s upper surface but below the protrusions in a generally horizontal arrangement and either in a sandwich relationship with a later positioned upper grill or, more preferably, in a spaced above end below relationship relative to the lower and upper grills, respectively (for improved cooking fluid contact on all exposed surfaces of the food item). Alternatively, the food piece is placed in a one, two or more prong skewer relationship with the racks prongs with or without an above positioned grill. Additional steaks, pork chops or other food items can then be supported on the upper portion of the prongs without an added upper grill (pieces placed above and in contact with the protrusions or more preferably suspended thereabove, and either in a vertical orientation with one prong extending through one or a plurality of serially arranged food pieces or in a horizontal relationship with either one prong extending through or more preferably two prongs extending through different sections of the generally horizontally arranged pieces). More preferably when dealing with steaks and the like, a first set of food items are placed on the prongs and then the upper grill is slid in position as described above and a second set of food pieces are arranged on the prongs either vertically or horizontally as described above and preferably spaced above the upper surface of the upper grill. Thus, while the food piece can be placed in contact with the upper grill, it is more preferable, based on prong friction, to suspend the food pieces above the upper grill rack to help facilitate overall oil passage (with the upper providing a slip down grill protection feature which could still provide relatively good oil/food surface contact which would be lessened in a food to food contact situation). Also the food pieces, when in position on the upper grill, help to lock the grill in position, although additional means such as a double protrusion arrangement featuring a smaller-relatively easier slide over protrusion above a larger support protrusion space there below are also representative of the present invention. The spacing between the upper and lower grills can be chosen to suit the intended need of a customer. For example, if food pieces that are not readily suited for prong insertion, the grills can be placed at a spacing to sandwich those non-pronged pieces to maintain them in position during the turbulence of the cooking medium. Thus the rack can be used in this non-prong food fashion, or only in a prong food support fashion or a combination of the two techniques with the same or different food pieces. Various levels of multiple protrusions for a single prong can also be provided through use of compressible protrusions, although a relatively rigid single protrusion per prong is preferable.
Alternatively the rack device can embody the lower grill and rack free of the upper grill. This represents an embodiment well suited for deep frying smaller poultry such as Cornish Hens which the prongs can penetrate into to hold the pieces in position during cooking.
The preferred arrangement for the rack device, and one well suited for use in deep frying in oil, features four prongs that have a common base either defined by the grill or more preferably an interconnected base extension such as pair of joined together base extension support bars. In a preferred embodiment the rack device features two rack sections each comprised of two diametrically opposed prongs with a common diametrically extending base extension with the extension of one fixed to the other such as by welding at an overlap location preferably with a recess provided in one in the area of overlap to keep the remainder of the base extensions at a common level. Also the diameter defined by interconnecting points of the prongs at the level of the lower grill is preferably concentrically arranged with regard to a preferred circular lower grill and at an intermediate location (e.g. a radial location at 25 to 75% of the full radius of the lower grill and more preferably about 40 to 60% of that radius and even more preferably 50%). The lifting extension is preferably welded or otherwise permanently fixed to the based section at a location which is preferably relatively close to the central point of the base section (e.g., a lifting extension inward contact point within one to two inches of the base section with a lifting extension base the extends radially outward to position a vertical bar of the lifting extension at the above noted grasping hook radially external hook location.
The prongs are preferably sized so as to sufficiently penetrate a wide assortment of food piece sizes (e.g. a 1 to 5 inch height is well suited for this purpose with a 3 to 4 inch range preferred). The lifting extension with a preferred integral grasp loop included preferably extends higher than the preferably sharpened free ends of the prongs (e.g., a 5 inch height). The base extensions are preferably about 6 inches in length and criss-crossed in a transverse arrangement with equal spoke lengths. The grills are preferably formed with a larger outer radius than a circumference contacting the prongs.
In use, the pieces to be cooked are supported on one of the above noted variations of the rack device in one of the above noted variations for supporting the pieces on the rack and/or rack and grill assembly and placed in the pot either alone or in conjunction with a basket as described above. In the pot there is provided a suitable cooking medium such as oil at a level preferably sufficient to completely immerse the pieces when the rack is in position. The cooking medium is used to cook the pieces and when cooking is complete a grasping hook or the like is used to engage the lifting extension whereupon an upward lifting force is used to remove the rack device from the frying apparatus. In one embodiment, the cooking basket is provided with capture means such as a side wall hook which can be connected to the pan""s upper rim to hold the cooking basket above the oil level. This can therefore provide, for example, for the removal of the rack device directly out of the container(s) or indirectly by first removing or lifting up a basket (and preferably attaching to the side of the pot through use of a hook assembly) to be free of the cooking medium and then removing the rack device from the basket. In either situation, the peripheral arrangement of the lifting extension enables a user to incline the rack device prior to complete removal to allow for cooking medium drip off at a location where vaporized cooking medium is likely not to be the most prominent. This tilting is facilitated by using a grasping hook/loop combination relative to grasp handle and lifting extension. Thus, tilting of the rack device in combination with an earlier hooking of a basket to the top edge of the pot for drainage purposes, facilitates a rapid and extensive drain off of oil off the food. For example, the basket with rack device supported on its base is first lifted partially out of the pan and hooked into position to achieve a drainage of the oil on the rack, food products, and basket (with drain holes, for example). Thereafter, the rack can be partly withdrawn from the basket and lifted relative to the pot so as to assume a tilted position where additional oil drains off prior to moving to a food preparation surface.
A second preferred embodiment of the rack device of the present invention is one which is free of the above noted upper and lower grills. This alternate embodiment comprises the rack alone with reliance placed on the criss-crossing base extensions (or alternate base structure) for pot or basket contact and features a peripherally arranged lifting extension (e.g., a lifting extension that vertically extends upward from a point on a horizontal plane that is commensurate with a circumferential circle that connects the base of the vertical prongs or is either further radially out from that interconnecting circle). As above, this peripheral arrangement achieves the drain off advantage described above in that the pronged or otherwise held in place food pieces are inherently tilted during lift up on the lifting extension with, for example, a grasping hook.

Rack device well suited for use with a deep frying apparatus and method of using the same