Disclosed is a process of manufacturing a lightweight particulate cementitious composition particularly adapted to the sorption of liquids comprising adding to a foamed cement slurry a particle forming agent, and aging the treated foamed slurry for a period of time sufficient for the particles to form and harden for subsequent handling. The bulk density, particle size distribution, and concentration of the agent are selected such that the cementitious composition has the desired density and such that at least 65% of the particles obtained after aging have the desired particle size.

Heretofore, many efforts have been made to develop an effective and inexpensive litter for animals, especially household pets, particularly cats. Thus it has been disclosed in various patents to use alone or in various combinations urine sorptive materials, odor-inhibiting or control chemicals or materials, anti-oxidants, microbial inhibitors, surfactants, dyes, anti-static agents, flame retardants, binders, encapsulants, neutralizing agents, weighting or density control agents, and other materials. Representative of the many materials disclosed to provide one or more of these characteristics are: siliceous minerals such as natural or synthetic clays (bentonite, attapulgite, fuller's earth, sepiolite, kaolin), diatomaceous earth, mica, talc, sand, finely divided quartz, vermiculite, perlite, fly ash, pumice, zeolite molecular sieves, opalite, bottom ash, boiler slag, synthetic porous silicas and silicates, hydrophobic microporous crystalline tectosilicates of regular geometry having aluminum-free sites in a siliceous lattice, and the like; natural or agriculturally-grown materials and by-products thereof, such as chlorophyll-containing materials (alfalfa, algae, broome grass, timothy grass, metallic chlorophyllin salts, stems and leaves of leaf meal such as ipilipil niseacacia, etc.), permit shells, cedar, wood shavings, sawdust, wood flour, bagasse, corncobs, sugar beet pulp, citrus pulp, alpha-cellulose fiber stock, sulphite cellulosic paper stock, waste paper, paper sludge, hay, husks, bark, straw, gelatinizable carbohydrates, sunflower hulls, partially pyrolyzed cellulosic materials, sagebrush, sorghum, cotton seed hulls, popcorn, peat moss, tomato pumice, grain, potato, cereal or grain hulls such as corn, rice, wheat, oats, and the like, apple pulp and grape pulp; foamed plastics (polystyrene, polyurethanes, phenolic resins, cellular cellulose acetate, etc.); porous plastic beads; cloth, synthetic sorptive granules based on commercial grade plaster (calcium sulfate dihydrate); wax or paraffin coated hydrophobic substantially non-sorbent and non-water wettable granular material; porous inorganic material which has been uniformly contacted with a gaseous or liquid acidic substance to neutralize alkalinity therein and provide a pH between 5.8 and 6.2; porous inorganic material treated with a water-soluble zinc salt having a pH from approximately 7 to 9; absorbent pads; calcium carbonate; Portland cement; activated carbon; alumina; coal residues; recycled molasses serum; in-situ polymerized monomer or monomers containing at least one acidic functional group present in the molecule; water soluble or dispersible materials having colloidal properties in water including silicates, preferably alkali metal silicates, pyrophosphates, preferably alkali metal pyrophosphates, polysaccharides, preferably cellulose derivatives, alginates, or starch; polyvinylpyrrolidone; anhydrous sodium sulfate; citric acid; sodium chloride; sodium or ammonium persulfate and a buffering agent; water absorbent polymers; adhesive-type soluble lignin pelletizing aid; cyclodextrin; thermoplastic polymers; crosslinkable natural gums such as the polygalactomannan gums, xanthan gum, or alginate; pheromone-like attractant substances; a veterinary composition for preventing feline urological syndrome; Plaster of Paris, calcined alkaline earth metal oxides; aluminum sulfate; carbonates, bicarbonates; hydrogen phosphates; benzaldehyde green; rose bengal; certain quaternary ammonium compounds; proprionates; N-alkylpyridinium proprionates; halogenated aromatic hydrocarbons; undecylenic acid; aldehyde derivatives; thiocyanates; carbamates; azo chlorides; modified phenols; oxyalkylated alkylphenols; alkyl sulfate salts; alkylbenzene sulfonate salts; oxyalkylated alcohols; water soluble or dispersible gums and polymers, such as guar gum, micro-crystalline cellulose, pregelatinized starches, methacrylic and acrylic polymers and copolymers, cellulose derivatives (carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose), polyvinyl alcohol, polyethylene oxides, carbohydrates, and proteins; starch graft copolymers and other so called super absorbents; camphane derivatives; various aromatic oils such as pine oil, citrus oils, oil of cloves, and cinnamon oil; methanol; camphor; sodium dihydrogen phosphate; potassium dihydrogen phosphate; potassium acid phthalate; cherry pit extract; certain hydroxamic acids and salts thereof; perfumes; fragrances; vitamin E; chlorine dioxide; sodium bicarbonate; gypsum; sagebrush oil; microencapsulated fragrance or deodorizer; salts of transition metals of Group Ib or Group IIb of the periodic table of the elements; ferrous sulphate heptahydrate; borax; and p-hydroxybenzoate.
In spite of the wide variety of materials and combination of materials disclosed for use as animal litter, particularly cat litter, there is still a need for a superior sorbent which eliminates the odors associated with the decomposition of animal urine.
A primary object of the present invention is to provide a process for the manufacture of lightweight particulate cementitious compositions useful as a sorbent for various liquids, such as the absorption of urine in cat litter boxes.
Another primary object of the present invention is to provide a lightweight particulate cementitious cat litter which can be manufactured at any desired location by environmentally acceptable processes requiring low energy input.
An object of this invention is to provide lightweight sorptive cementitious compositions which are adapted to be cohesive when wetted with an aqueous medium, such as urine.
Still another object of this invention is to provide methods for decreasing the odor from animal litter boxes utilizing the particulate cementitious sorbents of this invention.
Another object of this invention is to provide a method of making the particulate cementitious sorbents of this invention cohesive when wetted with an aqueous liquid, such as urine.
The improved sorbent compositions of the invention are produced from (a) a cementitious material such as Portland cement, alumina cement, gypsum cement, gypsum plaster, magnesia cement, and calcium-aluminate cement; (b) water which is used in processing; (c) an air entraining or foaming agent; (d) a particle forming agent; and, optionally, (e) plasticizers to reduce the water content during manufacture; (f) additives to improve the sorption capacity of the sorbents; and (g) other additives as desired to provide the sorbent compositions with any desired characteristics.
The sorbent compositions of this invention are produced by novel processes comprising: (I) - (1) forming a foamed aqueous slurry containing water and a cementitious material in a water to cementitious material weight ratio from about 0.2 to about 1.2, the slurry containing from about 0.1% to about 5% by weight of the water of a foaming surfactant, from 0% to about 10% based on the weight of the cementitious material of a sorption capacity increasing additive, and from 0% to about 20% based on the weight of the cementitious material of a plasticizer for the cementitious material; (2) mixing with the foamed slurry a particle forming agent; and (3) aging the foamed slurry for a period of time sufficient for the particles to form and harden for subsequent handling; wherein the bulk density, particle size, and concentration of the particle forming agent are selected such that the cementitious composition has the desired density and such that at least 65% of the particles have the desired particle size; or (II) - (1) forming an aqueous slurry containing water and a cementitious material in a water to cementitious material weight ratio from about 0.15 to about 1.0, the slurry containing from about 0% to about 20% based on the weight of the cementitious material of a plasticizer and from about 0.1% to about 5% by weight of the water of a surfactant; (2) foaming the aqueous slurry by either (a) vigorously mixing the slurry and entraining air therein, (b) mixing with the aqueous slurry a pre-formed foam containing from about 1% to about 10% by weight of a foaming agent, or (c) both (a) and (b); (3) mixing with the foamed slurry a particle forming agent; and (4) aging the foamed slurry for a period of time sufficient for the particles to form and harden for subsequent handling; wherein the bulk density, particle size, and concentration of the particle forming agent are selected such that the cementitious composition has the desired density and such that at least 65% of the particles have the desired particle size.
While the invention is susceptible of various modifications and alternative forms, specific embodiments thereof will hereinafter be described in detail and shown by way of example. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed, but, on the contrary, the invention is to cover all modifications and alternatives falling within the spirit and scope of the invention as expressed in the appended claims.
The compositions can comprise, consist essentially of, or consist of the stated materials. The method can comprise, consist essentially of, or consist of the stated steps with the stated materials.
The lightweight particulate cementitious materials of this invention are prepared by novel processes which maximize the percent recovery of particles in the desired particle size range. These processes comprise: (I) - (1) forming a foamed aqueous slurry containing water and a cementitious material in a water to cementitious material weight ratio from about 0.2 to about 1.2, the slurry containing from about 0.1% to about 5% by weight of the water of a foaming surfactant, from 0% to about 10% based on the weight of the cementitious material of a sorption capacity increasing additive, and from 0% to about 20% based on the weight of the cementitious material of a plasticizer for the cementitious material; (2) mixing with the foamed slurry a particle forming agent; and (3) aging the foamed slurry for a period of time sufficient for the particles to form and harden for subsequent handling; wherein the bulk density, particle size, and concentration of the particle forming agent are selected such that the cementitious composition have the desired bulk density and such that at least 65% of the particles have the desired particle size; or (II) - (1) forming an aqueous slurry containing water and a cementitious material in a water to cementitious material weight ratio from about 0.15 to about 1.0, the slurry containing from about 0% to about 20% based on the weight of the cementitious material of a plasticizer, from about 0.1% to about 5% by weight of the water of a surfactant, and from 0% to about 10% based on the weight of the cementitious material of a sorption capacity increasing additive; (2) foaming the aqueous slurry by either (a) vigorously mixing the slurry and entraining air therein, (b) mixing with the aqueous slurry a pre-formed foam containing from about 1% to about 10% by weight of a foaming agent, or (c) both (a) and (b); (3) mixing with the foamed slurry a particle forming agent; and (4) aging the foamed slurry for a period of time sufficient for the particles to form and harden for subsequent handling; wherein the bulk density, particle size, and concentration of the particle forming agent are selected such that the cementitious composition has the desired bulk density and such that at least 65% of the particles have the desired particle size.
These processes require that an aqueous cementitious material-containing slurry be foamed, and thereafter the foam is treated to form the lightweight particle sorbents. The slurry can be foamed using an in-situ foam generation process, mixing the slurry with a pre-formed foam, or combination thereof. In the in-situ form generation technique, a foaming agent (air-entraining agent) is incorporated into the slurry and the slurry is foamed while agitating the slurry. Compressed air or other non-flammable gas can be injected into the slurry while agitation to more quickly create the desired foam density. In the pre-formed foam process, a portion of the required water is admixed with a foaming agent and passed, generally with compressed air or other non-inflammable gas, through a foam generator to produce a foam which is then mixed into the slurry containing the remainder of the water and the cementitious material.
These processes can be characterized as follows. First the cementitious material and water are mixed to form a slurry having the desired water (W) to cement (C) weight ratio. Generally, a plasticizer will be added to the slurry, preferably to the water before adding the cementitious material, when the W/C ratio is less than about 0.4. If it is desired to incorporate a sorption capacity increasing additive in the sorbent, it is preferred that it be first dispersed in the water used to prepare the slurry before mixing the cement therein. However, it can be added to the slurry before or after the foaming thereof. A surfactant is added to the slurry. If the foam is to be generated in-situ, this surfactant must be an air-entraining or foaming agent. Thus when the slurry is agitated a foamed slurry will result. If the foamed slurry is prepared by a pre-foam process, then this surfactant need only be a surface active agent which is compatible with the foaming agent used to prepare the pre-foam. Thus if the foaming agent is non-ionic, the surfactant may be either non-ionic, cationic, or anionic. If the foaming agent is anionic, then the surfactant may be non-ionic and/or anionic. If the foaming is cationic, that the surfactant may be non-ionic and/or cationic. Preferably the surfactant is the same as the foaming agent used to prepare the pre-foam. The slurry is then foamed by either (a) entraining air therein, (b) mixing the slurry with the pre-formed foam, or both (a) and (b).
The foamed cementitious material-containing slurry is then treated such that a particulate sorbent is formed. This comprises mixing with the foamed slurry a particle forming agent. The bulk density, particle size, and concentration of the particle forming agent are selected such that the sorbent has the desired bulk density and such that at least 65% of the particles which are eventually formed have the desired particle size, preferably at least 70%, as discussed hereinafter. The foamed slurry is then aged in a suitable vessel for a period of time sufficient for the particles to form and harden for subsequent handling.
The particles are then dried and classified to obtain the particles having the desired particle size. The drying may be carried out at ambient or elevated temperatures. The more water removed on drying, the lower will be the bulk density and, generally, the greater will be the sorption capacity. Alternatively, the drying can be eliminated and the sorbent particles will naturally dry at ambient temperature when placed in the litter box. The classification of the particles may be accomplished by known processes such as sifting through screens or by utilizing air classifying equipment.
Some of the particles may be bound or cemented together into a cluster of particles upon drying. These clusters are easily broken up without the generation of fine particles to enhance the percent recovery of the particles having the desired size.
The treatment of the foamed cement slurry to form the lightweight particulate cementitious sorbents of this invention is unique and impressive. Depending upon the concentration of the particle forming agent, the particles may form rapidly or only after extended aging of the slurry for several hours. Once the particles form the foam breaks and there is no outward appearance that any foam ever existed after the particles have hardened sufficiently to be subsequently handled without crushing. Most of the particles are rounded, spheroidal or elipsoidal in shape. The strength of the particles is dependent upon their composition, and particularly on the weight ratio of water to cementitious material used in preparing the sorbent, the particular cementitious material and particle forming agent used, and the weight ratio of particle forming agent to cementitious material. The lower the water to cementitious material ratio, the greater will be the particle hardness and bulk density.
The cementitious materials useful in the practice of this invention are hydraulic substances which the property of undergoing a hydration reaction resulting in hardening. Typical examples of such substances are Portland cement, alumina cement, gypsum cement, gypsum plaster, magnesia cement, and calcium aluminate cement. Portland cement is preferred.
The air-entraining or foaming agents which are useful in the practice of this invention may be selected from any of the known surface active agents or surfactants which have been disclosed for use in preparing foamed cement. See for example the following U.S. patents, incorporated herein by reference: U.S. Pat. No. 3,782,983 (Komor); U.S. Pat. No. 3,963,507 (Kuramoto et al.); U.S. Pat. No. 4,019,916 (Golightly et al.); U.S. Pat. No. 4,046,582 (Kawamura et al.); U.S. Pat. No. 4,828,619 (Matsushita et al.); U.S. Pat. No. 4,836,855 (Caillan et al.). These patents, and patents referenced therein, disclose the use of Finsol resins; sulfate esters having the empirical formula EQU R-(OCH.sub.2 CH.sub.2).sub.n SO.sub.4 A
wherein R is an alkyl group of about 8 to 10 carbon atoms or an alkyl-substituted aryl group such as phenyl or naphthyl wherein the alkyl group contains 2 to 7 carbon atoms and may be straight or branched chains, "n" is zero or an integer of one or above, preferably zero up to about 10, and A is H or a salt forming cation selected from the group consisting of alkali metal such as sodium, potassium, or lithium, NH.sub.4 and mono-, di-, or tri-lower (1 to 6 carbon atoms) alkyl or alkylol amino and heterocyclic secondary amino groups; a foaming agent comprising:
1. as the foaming component, 0.05 to 20, preferably 0.1 to 10, parts by weight of a water-soluble, low viscosity cellulose derivative having a viscosity at 20.degree. C. of 25-2,000, preferably 100-2,000, centipoises at 2 wt % aqueous solution. PA1 2. as the foam stabilizer, 1 part by weight of a water-soluble, high-viscosity cellulose derivative, of which 2 wt % aqueous solution has a viscosity at 20.degree. C. of more than 2,000 centipoises, preferably more than 4,000 centipoises, and PA1 3. as the foaming accelerator, at least 1 part, preferably 1 to 30 parts, particularly 1 to 10 parts, by weight of at least 75% saponified, more preferably at least 85% saponified polyvinyl alcohol, of which 4 wt % aqueous solution has a viscosity at 20.degree. C. of not higher than 70 centipoises;
ethoxylated materials including alcohols, alkyl phenols, and polyalcohols; sulfated materials including alcohols, ethoxylated alcohols, alkyl phenols, ethoxylated alkyl phenols, dialkyl esters of succinic acid, and the like; sulphosuccinamates having the empirical formula EQU RHNCOCH(SO.sub.3 M)CH.sub.2 COOM or RNHCOCH.sub.2 (SO.sub.3 M)COOM
wherein R is preferably a saturated or unsaturated hydrocarbon group having at least 4, preferably 8 to 22, e.g., 12 to 18, or 10 to 14 carbon atoms, especially 12 carbon atoms, or an alkylalkoxy, alkylpolyalkoxy, alkenylalkoxy or alkenylpolyalkoxy group wherein the alkyl or alkenyl moiety has at least 4 e.g., to 9 to 22 preferably 10 to 14 carbon atoms, the alkoxy group is preferably ethyleneoxy and the group preferably contains an average of 1 to 20 alkyleneoxy moieties, e.g., 3 to 7 most preferably to 6, and each M is preferably alkali metal, aluminum or an organic base-the "M's" may be the same or different; higher secondary alcohol oxyalkylene sulfates having the empirical formula ##STR1## wherein R and R.sup.1 are alkyl group with the sum of the total number of carbon atoms of both R and R.sup.1 being about 10 to 20; n and m are each an integer of from 0 to 15, with n+m being 1 to 15, and M is an alkali metal atom, an ammonium group or an amine group; polyoxyethylene polyalcohol fatty acid esters; and various protein hydrolyzates. Protein hydrolyzates are made by hydrolyzing substances such as keratins and albumens which are found in animal hooves, horns, feathers and blood. They are employed as aqueous compositions (bases) which often contain one or more additives such as stabilizers, preservatives and complexing agents, e.g., iron salts, zinc salts, sodium citrate and sodium chloride, all of which are known additives to improve solution-stability and properties such as foam stability and foam-drainage. The hydrolyzed protein bases employed in the present invention usually have a pH of less than 9, e.g., from 6 to 8.
Other surfactants useful in the present invention include amine oxides having the empirical formula EQU RR'.sub.x R".sub.y N(.fwdarw.O)[(CH.sub.2 CH.sub.2 O).sub.n H].sub.m
wherein: R is an aliphatic group of about 8 to 18 carbon atoms, preferably an alkyl group of about 8 to 14 carbon atoms; R' is an aliphatic group of about 1 to 18 carbon atoms, preferably a methyl group; R" is a methyl group; n is an integer of 1 or above, preferably one; and x, y, and m are zero or integers one or two wherein x+y+m=2.
Mixtures of amine oxides and sulfate esters of ethoxylated alcohols are particularly useful surfactants in the present invention.
The particle forming agents (PFA), which are the key to the success of the novel process to provide a particulate cementitious composition wherein at least 65% of the particles have the desired particle size, are water absorbent materials. They appear to function by absorbing water from the foamed slurry resulting in a coating of the solids in the foamed slurry over the surface of the PFA particles. As the water is absorbed by the particle forming agent, the foam is dissipated resulting in the cementitious material coating the particle forming agent. Thus the novel processes described herein can also be considered as process of coating water absorbent materials with cementitious compositions.
The PFA can be chosen from a wide variety of water absorbent materials. Representative PFA include: clays such as bentonite, attapulgite, hectorite, sepiolite, fullers earth, montmorillonite and the like; heat expanded perlite; exfoliated vermiculite; porous silicates; natural zeolites; ground vegetable materials, such as corn cobs, citrus pulp, beet pulp, rice hulls, oat hulls, waste cellulose, ground paper, cotton fiber from the deliniting of cottonseed, peanut hulls, bagasse, alfalfa, ground cotton burrs (gin trash), and the like; water absorbent polymers such as pregelatinized starch, starch ether derivatives, starch graft copolymers, cellulose derivatives, and synthetic polymers or copolymers such as polymers containing a monomer selected from the group consisting of acrylic acid, acrylamide, acrylonitrile, methacrylic acid, methacrylamide, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinyl sulfonate, the alkali metal salts thereof, and mixtures thereof, and mixtures of these water absorbent materials.
In general, the particle size and concentration of the PFA controls the particle size of the particulate cementitious sorbents produced. Thus as the particle size of the PFA increases, the particle size of the particulate cementitious sorbents increases. Increasing the concentration of the PFA decreases the particle size of the particulate cementitious sorbents produced. To prepare the preferred cat box sorbents of this invention, it is preferred that at least 75% of the particles of an inorganic or ground vegetable material PFA are less than about 2000 microns and greater than about 149 microns, most preferably at least 65% of the particles of these PFA are greater than 250 microns. Water absorbent polymer PFA may be powdered materials depending on the water absorption characteristics of the polymer and the concentration added. Thus the so-called "super slurper" polymers, generally starch-acrylonitrile graft polymers, acrylic acid-acrylamide copolymers, and the like, which have a large water absorption capacity can be finely powdered.
For any particular PFA desired, the optimum particle size and concentration required to give the desired % recovery of the desired particles of the particulate cementitious sorbents can be readily determined for any foamed cementitious material containing slurry.
Additives to improve the sorption capacity of the absorbent compositions of this invention may be chosen from a wide variety of powdered water soluble polymers, such as those disclosed in the book entitled "Handbook of Water Soluble Gums and Resins," Robert L. Davidson, Ed., McGraw-Hill Book Co., 1980, incorporated herein by reference.
Exemplary water soluble polymers include: starch, gelatinized starch, and derivatives thereof, such as carboxymethyl starch, hydroxyethyl starch, hydroxypropyl starch, and mixed ether starches; cellulose ethers and esters such as hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, sulfoethyl cellulose, carboxymethyl hydroxyethyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, cellulose sulfate, and the like; natural gums and synthetic biopolymers such as guar gum, locust bean gum, xanthan gum, sodium alginates, gum ghatti, gum karaya, gum tragacanth, and tamarind gum; pectins; casein and collagen protein colloids; and synthetic water soluble polymers, copolymers, terpolymers and the like, such as polyacrylates, polyvinyl alcohols, polyacrylamides, polyvinylpyrrolidones, poly(ethyleneoxide), polyvinyl acetates of varying degrees of hydrolysis, graft polymers, and the like.
Other additives which can be added to improve the water sorption capacity include powdered clays such as bentonite, attapulgite, hectorite, sepiolite, fullers earth, montmorillonite, and the like.
The plasticizers (water reducers is a synonymous term) or superplasticizers which may be utilized in the practice of this invention are well to known to those skilled in the cement art. They are described in U.S. Pat. Nos. 4,310,486 and 4,088,808 to Cornwell et al. and U.S. Pat. No. 4,495,228 to Cornwell. The water reducers are defined in ASTM C-494, types A and F mixtures. The purpose is to reduce the amount of water necessary to form a sufficiently plastic concrete mixture, (thereby improving the hardened material properties) to reduce setting time. One type of plasticizer is a mixture of (1) a condensate of formaldehyde and the sodium salt of naphthalene sulfonic acid (90%) and (2) 10% sodium gluconate as described in U.S. Pat. No. 3,686,133. There are numerous types of water reducers which are based upon condensation of alkaline earth metal sulfonate and formaldehyde. One preferred plasticizer is Daracem.RTM. 100 which is obtained from W. R. Grace, Cambridge, Mass. and described in U.S. Pat. No. 4,460,720. These compositions include an alkali polyacrylate with a molecular weight between 500-25,000 with an alkaline earth lignin sulfonate or alkaline earth polynaphthaleneformaldehyde condensate to reduce the amount of water necessary to form a plastic mixture.
Other known materials in the amounts conventionally employed may be added provided that they do not adversely effect the characteristics of the lightweight particulate cementitious compositions of this invention. Such materials include odor control compounds, microbial inhibitors (bacteriostats, fungicides, etc.), attractants, dyes, pigments, powdered lightweight aggregates, wetting agents, materials to increase the hardening (set) time, and the like. Representative odor chemicals are disclosed in the following U.S. patents, incorporated herein by reference: U.S. Pat. No. 3,636,927 (Baum); U.S. Pat. No. 3,675,625 (Miller); U.S. Pat. No. 3,735,734 (Pierce); U.S. Pat. No. 3,816,577 (Neckermann); U.S. Pat. No. 3,921,581 (Brewer); U.S. Pat. No. 4,219,094 (Stockel); U.S. Pat. No. 4,355,593 (Stapley); U.S. Pat. No. 4,727,824 (Ducharme). Representative microbial inhibitors are disclosed in the following U.S. patents, incorporated herein by reference: U.S. Pat. No. 3,765,371 (Fisher); U.S. Pat. No. 3,828,731 (White); U.S. Pat. No. 3,892,846 (Wortham); U.S. Pat. No. 4,494,482 (Arnold); U.S. Pat. No. 4,517,919 (Benjamin et al.). A phermone-like attractant is disclosed in U.S. Pat. No. 4,263,873 (Christianson), incorporated herein by reference. A veterinary composition for preventing feline urological syndrome is disclosed in U.S. Pat. No. 4,402,941 (Vaillancourt), incorporated herein by reference.
The lightweight particulate cementitious sorbents of this invention remarkedly eliminate the odors from animal urine, particularly cat urine, over a considerable period of time. The sorbents sorb the urine and spread it over an area large enough that the moisture evaporates rapidly therefrom, thus eliminating the moisture necessary for the biological decomposition of the odor causing organic components of the urine. Additionally, the acids in the urine are neutralized further eliminating odor. The animal feces is periodically removed, preferably daily, thus eliminating the odors from the litter box. When used in this manner, the sorption capacity of the sorbent may be quite high as it is not desired to hold the urine within the sorbent for any extended period of time.
The lightweight sorptive cementitious sorbents of this invention have poor cohesiveness when wetted by the urine. Thus when the feces is removed from the litter box, usually only the sorbent attached to the feces is removed from the litter box. We have found that if it is desired to remove the urine from the litter box simultaneously with the feces, this can be accomplished by adding to the sorbents of this invention a water activated cohesive agent.
We have found that suitable water activated cohesive agents are selected from the group consisting of cold water soluble polymers, swelling clays, and mixtures thereof.
Particularly preferred cold water soluble polymers are cold water soluble polysaccharides and derivatives thereof. Preferred polysaccharides and alginates, carrageenates, agar gum, ghatti gum, karaya gum, tragacanth gum, pectins, gelatinized starch, tamarind gum, xanthan gum, other biopolymers, and derivatives of these polysaccharides, and cellulose derivatives, locust bean gum derivatives, starch derivatives, and mixtures of these polymers. Other cold water soluble polymers which provide cohesiveness to the lightweight sorptive cementitious compositions of this invention are synthetic polymers, including polyacrylates, polyvinyl alcohols, polyacrylamides, polyvinylpyrrolidones, poly (ethyleneoxide), polyvinyl acetates of varying degrees of hydrolysis, and mixtures thereof. Mixtures of the cold water soluble polysaccharides and the synthetic polymers can also be utilized. The term "cold water soluble polymers" as used herein is intended to mean polymers which, when mixed with water at ambient temperature, form a solution which exhibits non-Newtonian flow properties and film forming characteristics, and is not intended to comprise water swellable polymer whose "solutions" contain highly swollen gel particles of the polymer. The latter polymers are generally highly crosslinked water soluble polymers.
The water swelling clays useful as cohesiveness agents in the sorbents of this invention are smectite-type clays which have a cation exchange capacity of at least 50 milliequivalents per 100 grams of clay which have sufficient of the exchangeable cations being selected from the group consisting of sodium, lithium, and mixtures thereof, such that the clay exhibits osmotic swelling in deionized water.
The structure of the minerals of the smectite group of clay minerals comprises a 3-layer sheet structure wherein a central octahedral layer of principally alumina or magnesia is sandwiched between two tetrahedral layers of principally silica. In the tetrahedral layer, tetravalent Si is sometimes partly replaced by trivalent Al or Fe. In the octahedral sheet, there may be a replacement of trivalent Al by divalent Mg, or of divalent Mg by monovalent lithium atoms. In the smectite clay minerals where an atom of lower positive valence replaces one of higher valence, there results within the clay structure deficit of positive charge, or, in other words, an excess of negative charge. This excess of negative charge is compensated by the adsorption on the layer surfaces of cations which are too large to be accommodated within the interior of the crystal structure.
In the presence of water, the compensating cations on the layer surfaces may be exchanged by other cations when available in solution; hence they are called "exchangeable cations." The total amount of these cations can be determined analytically. This amount, expressed in milliequivalents per 100 gram of dry clay, is called the "cation exchange capacity" (CEC) or the "base exchange capacity" (BEC) of the clay.
In the stack of layers which form a smectite particle, the exchangeable cations are located on each side of each layer in the stack; hence they are present not only on the exterior surfaces of the particle but also in between the layers. When smectite clays are contacted with water or with water vapor, the water molecular penetrate between the layers. This so-called "interlayer swelling" leads to at most a doubling of the dry clay volume when four layers of water are adsorbed. However, for the swelling smectite-type clays useful in this invention, the swelling process continues and an amount of water is imbibed which is many times the volume of the original clay. The additional swelling is a result of the double-layer repulsive forces between the surfaces of the individual particles, which pushes them apart. The swelling is called "osmotic swelling" since the water tends to equalize the high concentration of ions between any two particles and the low concentration of ions far away from the particle surfaces in the bulk aqueous solution. As a result of this osmotic swelling, the clay/water system becomes a gel or colloidal solution depending on the concentration of the clay.
The water activated cohesive agent is preferably admixed with the lightweight sorptive cementitious sorbents of this invention. Alternatively, it can be coated onto the particles of the sorbents either from an aqueous solution or dispersion of the cohesive agent or from a non-aqueous suspension or slurry. It is particularly desirable to add the water activated cohesive agent soon after the particles have hardened sufficiently for subsequent handling. At this stage, the water activated cohesive agent also functions as a "parting" agent to keep the particles of cementitious sorbent from bonding together.
The minimum concentration of water activated cohesiveness agent added to the lightweight sorptive cementitious sorbents of this invention must be such that the mass (lump) of treated sorbent, formed upon being wet with an aqueous liquid such as urine, maintains its integrity upon movement, such as upon its removal from a cat litter box. In the case of the expensive water soluble polymers which function as water activated cohesiveness additives, the water soluble polymer is desireably chosen such that its concentration is from about 0.25% to about 10% by weight of the lightweight cementitious sorbent, preferably from about 0.5% to about 7.5%, and most preferably from about 0.5% to about 5% by weight. The concentration of swelling clay for adequate cohesiveness should be from about 1% to about 100% by weight of the lightweight particulate cementitious sorbent, preferably from about 2.5% to about 50%, and most preferably from about 5% to about 33% by weight.
It is preferred that the powdered water soluble polymer be admixed with the sorbent after sizing to the desired particle size range but before final drying, such that the moisture on further drying will help to adhere the water soluble polymer particles to the sorbent particles.
In order to prevent separation during shipping, it is preferred that the water activated cohesive agent have a particle size such that at least 35% by weight, most preferably at least 50%, of the particles are in the same particle size range exhibited by 90% by weight of the lightweight particulate cementitious sorbent particles. Thus in the case of the preferred lightweight particulate cementitious cat box sorbent of this invention, preferably at least 35% by weight of the water activated cohesive agent particles have a particle size in the 10/60 mesh range. Preferably the water swelling clay has a particle size range as follows: +10 mesh, less than 5%; 10/60 mesh, at least 60%; 60/100 mesh, less than 30%; -100 mesh, less than 10%.
The sorption capacity of the sorbents of this invention is preferably less than 3.0 g/cc if they are to be mixed with the water activated cohesive agent to form a cohesive cementitious sorbent.
Methods are known to measure the bulk density of solids. Thus the sample can be weighed into a graduated volumetric cylinder, compacted as by tapping, and measuring the volume of the compacted solids. The water sorption capacity for the purposes of describing this invention, is measured using the following procedure: a measured quantity of the sorbent is weighed into a pre-weighed or tared plastic weighing dish, generally 10.0 grams of sample; distilled water is added dropwise slowly until 2.0 grams has been added; the wetted sample is then covered with additional dry sample, generally 10 grams; this is aged five (5) minutes to allow for sorption and spreading of the water; thereafter the weight of the sample not wet by the water is determined by carefully pouring off the dry sample from the wetted sample; the sorption capacity in g/cc is calculated using the equation ##EQU1##
The particle size of the lightweight, sorptive, cementitious compositions of the present invention will depend on their end use. Generally the particle size will be less than 3 mesh, U.S. Standard Sieve Series (USSSS). Granular sorbents generally have a particle size in the range from about 3 mesh to about 60 mesh USSSS. Sorbents for use as the litter in cat boxes will generally range from 6/16 mesh or from 10/60 mesh, preferably from 10/50 mesh. The preferred lightweight sorptive cementitious sorbents of this invention have particle size distributions in the following ranges:
______________________________________ Large Size Regular Size ______________________________________ +6 mesh - <10% +10 mesh - <5% 6/16 mesh - >80% 10/50 mesh - >75% -16 mesh - <10% 50/60 mesh - <15% -60 mesh - <5% ______________________________________
The bulk density of the sorbents of this invention is dependent on many interrelated variables, such as:
(a) the particular cementitious material, air-entraining/foaming agent, plasticizer, sorption capacity increasing additive, and particle forming agent used in preparing the sorbents, as well as the concentrations of each of these materials;
(b) the relative amount of water used in preparing the sorbents; and
(c) the amount of water removal after the cementitious material has hardened. Thus the desired bulk density of the sorbents of this invention is obtained by controlling these variables during the manufacture of the sorbents.
The lightweight particulate cementitious compositions of the present invention have a bulk density in the range from about 0.3 g/cc to about 0.9 g/cc, preferably from about 0.45 g/cc to about 0.85 g/cc, and most preferably from about 0.5 g/cc to about 0.8 g/cc. The sorption capacity of the lightweight particulate cementitious compositions may vary over a wide range depending on the end use of the compositions. Thus if a cat box sorbent is desired which spreads the cat urine over a large area for rapid evaporation, then the sorption capacity, as defined herein, may be as low as 10 g/cc. A cat box sorbent which has been adapted to be cohesive when wetted with urine as discussed herein preferably has a sorption capacity greater than about 3 g/cc, preferably greater than 2 g/cc, and most preferably greater than 1.5 g/cc.
The following examples illustrate specific embodiments of the invention and are not intended to be limiting. Unless otherwise indicated, the air-entraining/foaming agent was HI-EXPANSION, a foaming agent sold by National Foam Systems. The bulk density and water sorption capacity were measured as set forth previously.
In the examples and throughout this specification, the following abbreviations may be used: g=grams, cc=cubic centimeters; gel=gallons; lb=pounds; psi=pounds per square inch; %=percent; .degree.F.=degrees Fahrenheit; C=cement; CP=cement plasticizer; FA=foaming agent; P=plaster, PFA=particle forming agent; PFA-1=attapulgite clay; PFA-2=expanded perlite; PFA-3=calcium montmorillonite; PFA-4=calcium montmorillonite; and PFA-5=calcium montmorillonite; PFA-6=pregalatinized starch, PFA-7=Wyoming bentonite; USSSS=United States Standard Sieve Series; W=Water. The particle size distribution of the particle forming agents evaluated are as follows:
______________________________________ Mate- % by weight rial +10 10/20 20/30 30/40 40/50 50/100 -100 ______________________________________ PFA-1 0 0 27.2 49.5 16.0 4.9 2.4 PFA-2 0.2 55.4 15.9 8.1 4.1 4.8 11.4 PFA-3 0 0.1 13.9 29.3 25.1 27.5 4.0 PFA-4 0 0 2.1 38.3 37.5 21.7 0.4 PFA-5 0 0 0 0 8.6 87.6 3.8 PFA-6 0 1.0 9.0 26.2 39.3 22.4 2.2 PFA-7 0 30.8 41.2 15.3 7.7 4.1 0.9 ______________________________________
All mesh sizes used in the description of particle sizes are in terms of U.S. Standard Sieve Series, Fine Series of 1940. A particle size designated +X indicates the particles were retained on a sieve of size X mesh. A particle indicated Y/Z indicates that the particles passed through a sieve of mesh size Y and were retained on a sieve of mesh size Z. A particle size designated -W indicates that the particles all passed through a sieve of mesh size W. The term "powdered" when used herein is intended to mean that greater than about 25% of the particles thereof are less than about 100 mesh (149 microns).

Lightweight particulate cementitious materials and process for producing same


A device for assembling and disassembling a tool with a tool holder, such as particularly a mandrel. The device is essentially constituted by a support frame (4) provided with a unit (5) for receiving and holding a tool holder (3), elements (6 and 7) for ensleeving and extracting a tool (2) coacting with an induction heating unit (8) for the portion (3') of the tool holder (3) adapted to receive the tool (2) by ensleeving.

The principle of hooping has been known for a long time, also in the context of assembling tools/tool holders.
Thus, there exist at present devices for hooping tools/tool holders with manual intervention for ensleeving, requiring the rotation of the tool holders, which do not guarantee the complete ensleeving over the desired height (with risk of loss of the tool being machined), and again others which do not have a safety of use necessary for industrial employment.
Moreover, the heating of the tool holders or of the tool/tool holder assembly is carried out at present either by direct application of flame, or by projection of radiant heat or a flow of hot air or again by conductive contact, the use of the two first heating techniques being often delicate in an industrial setting and the third heating technique being less efficacious in giving rise to too long a heating time.
Moreover, none of the known processes or device permits limiting heating to a value just enough to assemble or disassemble the tool with the tool holder.

Device for assembling and disassembling a tool with a tool holder

E.P.B. Emile Pfalzgraf (Societe Anonyme)


The invention deals with a measuring apparatus (1) comprising a body (11) with an interior (114) and an opening for accessing the interior (114) from outside the body (11), a rigid plunger (12) having an edge (1212) being identically shaped as an edge of a opening of a target vial, and a force sensor (13). The rigid plunger (12) extends though the opening of the body (11) into the interior (114) of the body (11). The edge (1212) of the rigid plunger (12) is arranged outside the body (11). The force sensor (13) is arranged in the interior (114) of the body (11). The rigid plunger (12) is movable relative to the body (11) and is coupled to the force sensor (13). The apparatus (1) can be used for measuring a force acting on the edge of the opening of the target vial for optimizing the adjustment of a vial closure facility.

Pharmaceutical products or medications are provided in various different forms including liquids, powders, pills and capsules for application. For example, many pharmaceutical products are applied to patients in liquid form by oral administration or injection. The pharmaceutical product usually is provided in a primary package which directly encases the pharmaceutical product. Examples of primary packages are blisters packages, pre-filled syringes, bags and vials.
In connection with primary packaging pharmaceutical products it often is of high importance that certain conditions specific for the pharmaceutical product can be fulfilled. Typically, pharmaceutical products are primary packaged in a sterile manner in order to prevent contamination and degeneration. The primary package including the pharmaceutical product then usually is further packaged, e.g. in carton boxes, for being conveniently transported, sold and the like.
As mentioned, common primary packages include vials and other containers such as syringes, infusion bags and cartridges. Vials typically have a hollow body in which the pharmaceutical product is arranged. The body comprises a neck with an open end which is surrounded by a flange-like edge. For closing vials, often an elastic rubber stopper is placed on the edge of the opening and held by a cap crimped around the rubber stopper and the edge of the body.
In order that the opening of the vial is sealed the rubber stopper has to be tightly arranged on the edge of the opening. For that purpose, it usually is pressed onto the edge such that it is slightly deformed. It is held in a pressed fashion by the cap which typically is made of plastic or metal.
On an industrial level packaging machines are commonly used for primary packaging pharmaceutical products in vials. Thereby, such machines often pneumatically press the rubber stopper together with the cap onto the edge. In this situation the cap is crimped around the rubber stopper and the edge such that a residual force can be held by the cap. Such residual force ensures that the stopper is still pressed on the edge after the vial has left the packaging machine.
Within such packaging processes it is important that the pressure or force applied during and after primary packaging is properly adjusted. On one hand it has to be prevented that when pressing the rubber stopper on the edge of the vial the force is too high such that the edge or the stopper is damaged. On the other hand it has to made sure that after primary packaging the residual force acting from the plunger to the edge is high enough such that the opening is tightly closed in a seal fashion.
For such adjustment modern packaging machines provide information about the pressure or force pneumatically applied, e.g. by a pneumatical cylinder acting on the cap and the stopper placed on the vial. However, for precisely determining the situation such information is not sufficient. For example, the process of crimping the cap applies pressure on the cap and the rubber stopper in addition to the pressure applied by the pneumatical cylinder. However, such additional pressure is not contained in the mentioned information. In consequence, the sum of the pneumatical and crimp pressures can result in a force damaging the stopper, e.g. such that it yields into the opening and the neck of the vial. Or as another example, the rubber stoppers can have different shapes and dimensions such that the pressure applied on the outside of the stopper does not allow for concluding on the force being in fact applied to the edge of the vial.
Therefore, there is a need for a device and a method allowing for gathering information about the conditions of a rubber stopper placed on a edge of an opening of a vial or a similar container for closing the vial or similar container in a precise and predefinable manner.


A chemically amplified positive resist composition is provided comprising an alkali-insoluble or substantially alkali-insoluble polymer having an acid labile group-protected acidic functional group, an alkyl vinyl ether polymer, a photoacid generator, and a benzotriazole compound in a solvent. The composition forms on a substrate a resist film of 5-100 μm thick which can be briefly developed to form a pattern at a high sensitivity and a high degree of removal or dissolution to bottom.

In harmony with the downsizing of electronic equipment, a rapid progress is recently made toward higher integration of LSIs and toward ASIC (application specific integrated circuits). For LSI mounting, multi-pin thin-film packaging is widely employed. Such multi-pin structures include protruding electrodes or solder bumps of at least 10 μm in height as the connecting terminal, while the technique for forming solder bumps is requisite. When bumps are formed on LSI by a plating technique, a photoresist material is used. While bumps of mushroom shape are formed using conventional thin film resist, such bump shape is difficult to increase the integration density by increasing the number of pins on LSI or reducing the pin spacing. It is then necessary to shape bumps with vertical sidewalls (or straight sidewalls) utilizing a thick film resist. The thick film photoresist subject to plating must fulfill many features including high sensitivity, vertical profile, and high resolution, as well as deformation resistance and crack resistance of the pattern during or after the plating step.
As the means for solving these problems, certain compositions are known in the art. For example, JP-A H10-207057 discloses a positive photoresist composition having an acrylic resin added for the main purpose of improving the plating resistance of bump-processing resist film. JP-B S46-16049 discloses an alkali-soluble photosensitive resin composition comprising a novolac resin, a naphthoquinonediazide-containing compound, and polyvinyl ether. Both the compositions are improved in crack resistance, but have a possibility that the pattern profile is degraded owing to the reduced contrast of resist film. Also a positive photoresist composition comprising a novolac resin and a hydrolyzate of an alkyl vinyl ether-maleic anhydride copolymer having a molecular weight of 20,000 to 80,000 is known from JP-A H06-202332. This system, however, is insufficient with respect to crack resistance during or after the plating step in the gold plating application.
On the other hand, since solder bumps must have a height of several tens of microns to about 100 microns (μm), the resist pattern formed therefor must accordingly have a depth of several tens of μm to about 100 μm. It is thus recommended that the resist material be coated as a very thick film having a thickness of several tens of μm to about 100 μm. This implies that the resist material adapted for solder bump pattern formation may have problems with respect to sensitivity and resist pattern profile. While positive resist compositions comprising a novolac resin and a naphthoquinonediazide-containing compound are commonly used in the art, as described in JP-B S46-16049 and JP-A 2004-198915, thick films thereof having a thickness of several tens of μm to about 100 μm are degraded in sensitivity, which reduces the productivity efficiency of pattern formation, causes the pattern profile to be tapered, and leads to profile deficiency against the requirement to shape bumps with vertical sidewalls (or straight sidewalls). For this reason, the solder bump-forming resist material requiring a film thickness of several tens of μm to about 100 μm prefers chemically amplified resist compositions to the positive resist compositions comprising a novolac resin and a naphthoquinonediazide-containing compound because a pattern with more vertical sidewalls can be formed at a higher sensitivity.
In connection with the chemically amplified resist composition used as the solder bump-forming resist material requiring a film thickness of several tens of μm to about 100 μm, when polyhydroxystyrene in which some phenolic hydroxyl groups are substituted with acetal groups as acid labile group is used as the base resin (JP-A 2002-006503), a problem arises that a long time is necessary for development because of the thick film. The long development time leads to drawbacks such as a time-consuming process and low production efficiency.
With respect to the electrolytic plating bath used in solder bump formation, strong acid based solder plating baths, known as high-speed plating baths, are often utilized for enhancing production efficiency. When the pattern of chemically amplified positive resist composition is immersed in the strong acid based solder plating bath, the strong acid system exposes the pattern to very rigorous conditions, giving rise to the problems that not only cracks generate as mentioned previously, but also the pattern swells and deforms. The base resin commonly used in chemically amplified positive resist compositions is polyhydroxystyrene in which some phenolic hydroxyl groups are substituted with acetal groups as acid labile group (JP-A 2002-006503). When a pattern of the chemically amplified positive resist composition having such acid labile group is immersed in a strong acid based solder plating bath, the acid labile group can be eliminated by reaction with the acid in the plating bath. Thus the pattern is locally made hydrophilic and progressively swollen. As a result, the pattern is deformed within a short time.
Although the chemically amplified positive resist composition is preferred as the solder bump-forming resist material, many problems remain unsolved including a long development time, and film swell and pattern deformation upon immersion in plating bath.
Another exemplary chemically amplified positive resist composition used as the solder bump-forming resist material is disclosed in JP 4403627 as a composition comprising a base resin having an acid labile group other than acetal group, the composition having improved crack resistance. The resin used therein includes units which undergo elimination reaction with an acid and become soluble in alkaline developer, for example, (meth)acrylate units having 1,1-dimethyl-3-oxobutyl and/or 2-benzyl-propan-2-yl as the acid labile group. These acid labile groups have the following characteristics. Now that the solder bump-forming resist composition is formed into a thick film, if a compound resulting from acid elimination has a boiling point of up to 20° C. under atmospheric pressure, it can gasify, remain within the film, and form large bubbles in the film, adversely affecting the pattern profile. For this reason, preference is given to the acid labile group which is acid eliminated to form a compound having a boiling point of at least 20° C. under atmospheric pressure. Allegedly the compounds resulting from acid elimination of the acid labile groups in the units of exemplary base resins have the characteristics.
The acid labile groups mentioned above are tertiary alkyl esters. Under conditions of the step of immersing in a strong acid based solder plating bath, the tertiary alkyl esters do not undergo reaction with the acid in the plating bath, as opposed to the acetal groups. These acid labile groups are characterized by stability and a least likelihood of pattern deformation.
However, the chemically amplified positive resist composition comprising a resin having a tertiary alkyl ester as acid labile group may fail to gain a high resolution in the lithography process of forming a resist pattern because the acid elimination reaction of the acid labile group is inferior to that of acetal groups. This detracts from the removal of resist material to the bottom of a pattern being formed, resulting in a pattern profile being tapered.
When the acid labile group has characteristics as described in JP 4403627, that is, the acid labile group is able to be acid eliminated to form a component having a boiling point of at least 20° C. under atmospheric pressure, a possibility that the compound resulting from acid elimination in the resist pattern undergoes secondary addition reaction with the polymer or other resist components or reverse reaction to generate the acid labile group again cannot be completely removed. For this reason, the resist material film which is to become alkali soluble after exposure and development is extremely reduced in alkali solubility, failing to gain a high resolution. If the compound resulting from acid elimination has a high boiling point or a large or bulky molecule, the secondary addition reaction or reverse reaction as pointed out above can take place significantly. The resist material becomes insolubilized and left where spaces must be formed via positive/negative reversal, that is, as positive tone. Inversely a phenomenon to form a pattern there or a problem to induce scum formation can take place. Since the film formed of the solder bump-forming resist material is as thick as several tens of μm to about 100 μm, there is a tendency that the secondary addition reaction or reverse reaction as pointed out above takes place.
Photoacid generators generally used in chemically amplified positive resist materials include organic acid generators of onium salt type and of non-onium salt type such as oxime sulfonate derivatives. When a chemically amplified positive resist film is patterned on a metal substrate such as copper substrate which is to be subjected to plating to form solder bumps, the acid generated by the acid generator may be deactivated by the influence from the substrate, or the acid generator itself may exhibit a quasi-decomposition behavior by the influence from the substrate. In this way, the acid generation function can be lost. The portion of the pattern which is located near the substrate is observed to be degraded, which is known as a footing profile or undercut profile that the pattern portion appears to bite into the substrate. The footing profile can be transferred to solder bumps near the substrate as cutouts, with a possibility that the pattern collapses. The undercut profile also degrades the profile of subsequently formed solder bumps. That is, the profile of the resist pattern is transferred to solder bumps, and footing of solder bumps is thus observed. Because of the footing, the size of solder bumps near the substrate deviates from the target value.
For the chemically amplified positive resist material used in the formation of solder bumps via a plating step, the selection of acid labile group is critical. It is critical to select an acid labile group which is stable against strong acid in the plating bath, which affords high reactivity with the acid generated by the acid generator so that acid elimination reaction may smoothly run, and thus displays a high resolution, and which does not detract from the high resolution performance since the elimination reaction does not entail secondary addition reaction or reverse reaction, when the relevant resist composition is subjected to the lithography pattern forming process. In addition, it is also important to seek for a resist composition from which a resist pattern can be formed on a metal substrate, typically copper substrate for solder bump formation, without any degradation like footing and undercut. It is urgently demanded to seek for an acid generator or to construct a resist material which avoids any degradation of the pattern profile by generation of bubbles or the like after acid elimination when subjected to the lithography pattern forming process.

This patent is subject to a terminal disclaimer.

Chemically amplified positive resist composition and patterning process


A disc-type coin sorter for sorting coin mixtures which include at least one coin denomination made of a soft metal such as aluminum, the sorter has a rotatable disc having a resilient top surface, a motor for rotating the disc, a stationary sorting head having a lower surface positioned over and closely adjacent to the upper surface of the disc and having an opening in the central region thereof for feeding coins between the opposed surfaces of the disc and sorting head, the lower surface of the sorting head being contoured to align the coins in a single file and single layer of coins, and then sorting the coins according to their respective sizes, the contoured lower surface having at least one region for pressing the soft-metal coins into the resilient pad, and at least one rotatable bearing member mounted in the pressing region of the sorting head for engaging soft-metal coins passing thereunder so as to provide a rotatable bearing surface which eliminates or reduces galling of the soft metal of the coin on that region of the sorting head.

1. Field of the Invention
The present invention relates generally to coin sorting devices and, more particularly, to coin sorters of the type which use a resilient rotating disc and a stationary sorting head for sorting coins of mixed denominations. The coin sorter of this invention is particularly useful with coin sets which included at least one coin denomination made of a soft metal such as aluminum, and/or in which the variation in thickness among the various coin denominations is very small.
2. Background Information
Although disc-type coin sorters with resilient disc have been used for a number of years, problems are still encountered in applying this technology to certain coin sets. For example, if the coin set includes one or more coin denominations made of a soft metal such as aluminum, the soft-metal coins tend to gall on the portions of the sorting head where the coins are pressed firmly into the surface of the resilient disc. The resulting metal deposited on the sorting head from such galling can result in the mis-sorting of coins.

Disc-type coin sorter with movable bearing surface


A method of forming a ceramic component is disclosed. A ceramic matrix material is combined with a binder material. The ceramic matrix material and the binder material are mixed to create an intermediate slurry. After mixing the ceramic matrix material and the binder material, reinforcing fibers are added to the intermediate slurry to create a final slurry. The final slurry is introduced into a mold cavity having a shape corresponding to the ceramic component. The final slurry is at least partially cured within the mold cavity to form an intermediate casting. The intermediate casting is sintered to produce the ceramic component from the intermediate casting.

Electronic devices often include housings that enclose some or all of the sensitive components of the electronic device. Traditionally, plastic has been used for electronic device housings, at least in part because it is inexpensive and easy to form into the shapes and geometries required for modern electronic devices. Increasingly, however, housings for electronic devices are being made from materials other than plastic. For example, housings that include glass, ceramics, and the like are being used for their superior hardness, optical properties, and aesthetic properties.

Fiber-reinforced ceramic matrix composite for electronic devices


An anti-theft brake locking mechanism for a motor vehicle. The motor vehicle includes one or more brake pedals disposed adjacent an interior surface of the vehicle. The anti-theft brake locking mechanism selectively maintains the brake pedal in a depressed position so as to actuate the vehicle brakes in order to prevent movement of the vehicle. The mechanism includes a hook portion engageable with the brake pedal stem, a neck to which the hook portion is mounted, and a base portion. The base portion is selectively secureable to and releaseable from a pedestal mounted to the vehicle floorboard.

This invention relates to an anti-theft device for a vehicle.
Various devices are known for interacting with various components of a vehicle, such as an automobile or the like, in an effort to prevent theft of the vehicle. It has been found that many of such devices are ineffectual in achieving this purpose so that, not withstanding presence of such a device on a vehicle, the vehicle can nonetheless be stolen.
This invention takes a different approach to preventing theft of a vehicle. In accordance with the invention, an anti-theft device is provided for a motor vehicle including a brake pedal disposed adjacent an interior surface of the vehicle. The anti-theft device comprises pedal engaging means, and retaining means connected to the pedal engaging means. The retaining means is selectively secureable to the interior surface of the vehicle for retaining the brake pedal in its depressed position, wherein the vehicle brakes are engaged. In this manner, movement of the vehicle is prevented when the retaining means is secured to the vehicle surface. When the retaining means is disconnected from the vehicle surface, movement of the vehicle is again allowed due to release of the brake pedal. In a preferred embodiment, the pedal engaging means comprises a hook-like member formed at the end of a neck extending outwardly from a base. A pedestal is firmly secured to the interior surface of the vehicle. The base is selectively mountable to and demountable from the pedestal. When the hook member is engaged with the brake pedal and the base secured to the pedestal, the brake pedal is maintained in its depressed position, wherein the brakes of the vehicle are engaged and movement of the vehicle is prevented. To assist in maintaining engagement of the hook member with the brake pedal, a block is preferably mounted to the brake pedal stem adjacent the upper surface of the brake pedal.

Anti-theft brake locking device for vehicles


A memory device can include at least one plate structure formed over a semiconductor substrate; an active region formed within the semiconductor substrate without lateral isolation structures; a plurality of bit line contact groups, each including bit line contacts to the active region disposed in a first direction; a plurality of storage contact groups, each including storage contacts to the active region disposed in the first direction; a plurality of gate structures, each including a main section extending in the first direction, and disposed between one bit line contact group and an adjacent storage contact group; and a two-terminal storage element disposed between each bit line contact and the at least one plate structure.

Memory devices that utilize programmable resistance elements to store data can provide advantages over other conventional memory types by providing lower operating voltages at relatively high densities. Further, some programmable resistance elements can be formed at the "bank-end" of an integrated circuit manufacturing process, and so not require substrate area. Thus, such elements can be easily incorporated into existing devices and/or processes.
One particular programmable resistance element can be a CBRAM type element. CBRAM elements can include one or more switching layers that can be programmed between two or more resistance states by application of electric fields. For example, an electric field applied in one direction can result in a higher resistance, while an electric field applied in other direction can result in a lower resistance. In some CBRAM elements, switching layers can undergo an oxidation-reduction reaction to arrive at such changes in resistance. The oxidation-reduction reaction may, or may not, include ion conduction.

Programmable impedance memory device and related methods


This combined ski boot and safety binding comprising a recessed boot receiving a binding case is adapted releasably to cooperate with a complementary member fastened to the ski, the case comprising pistons responsive to resilient return springs, the pistons being provided with transverse rods engaging cam contours formed on upstanding lateral lugs rigid with the complementary member; the boot is provided with a pivot member formed with opposite flat faces adapted to actuate the pistons when the boot is lifted and/or rotated as a consequence of a forward or backward fall, or in case of abnormal torsion stress, so as to release the boot and the case from the complementary member.

1. Field of the Invention
The present invention relates in general to ski boots and safety ski bindings, and has specific reference to a combined ski boot and safety binding comprising more particularly a ski boot and a safety ski binding assembly in which the binding is set or embedded in the boot sole and capable of releasably retaining the boot on the ski by cooperating with a complementary member secured to the top surface of the ski.
2. Description of the Prior Art
Ski boot and binding assemblies of this character are already known in the art, notably through the U.S. Pat. No. 3,899,190.
However, these known arrangements are objectionable for they are attended by the following inconveniences:
Under the boot sole there is provided either a recess or a relief portion adapted to cooperate with the complementary member carried by the ski. If a recess is provided, snow and mud may tend to accumulate therein when walking, and thus interfere with the proper operation of the safety release means. In the case of a relief portion, the skier's walk becomes uneasy.
Besides, the sole must be provided with non-skid notches or studs to permit walking. Yet, on the other hand, the coefficient of friction between the boot and the ski should be relatively low so that the boot can easily be released under torsion stress. These two contradictory requirements constitute a problem hitherto unsolved in the present state of the art.
The known assemblies of the type discussed herein do not provide any interaction between on the one hand the means retaining the boot against an upward movement in case of forward or backward fall, and on the other hand the means retaining the boot against rotation in case of a torsion stress. Now this interaction is extremely desirable from the point of view of safety. In fact, in case of complex fall, i.e. a fall combining torsion stress with a tractive stress, the skier's tibia is considerably more vulnerable than in case of a simple fall. Thus, when the skier is in a position of want of balance either forwards or backwards, his tibia may break under a lateral stress weaker than that required for breaking his tibia when he is in a normal position.


A housing for an electronic device includes a metal member combined with a plastic member. The combination molds the metal member to the plastic member but the plastic member is discontinuous and recesses and protrusions are cut into the metal member to enable molding and bonding with the plastic member in the manner of a dovetail joint. Manufacture in this way increases bonding strength and reduces the likelihood of internal stresses in the cooling plastic member resulting from complete envelopment of the metal by the plastic. The metal member and the plastic member are thus integrally formed and a thickness of a recess is less than a thickness of the plastic member. An electronic device and a method for making the housing are also provided.

Electronic devices are becoming lighter and thinner, and appearance of the electronic devices is also important. Therefore, a housing containing the electronic device should have good appearance, good mechanical strength, good heat dissipation, and other features.
The housing can include a metal member and a plastic member. The metal member and the plastic member are combined by insert molding technology wherein the metal member is put into a molding mold, then molten plastic is filled into the molding mold to solidify around the metal. The molten plastic may shrink and deform during a cooling process. The plastic member will have an internal stress due to the shrinking and the deforming, which may affect a quality of the housing.
Therefore, there is room for improvement within the art.

Housing, electronic device, and method for manufacturing the same

SHENZHEN FUTAIHONG PRECISION INDUSTRY CO., LTD.


An adjustable mounting bracket adapted to be movable in a vertical and/or horizontal plane, whereby a drawer and drawer-guide system can be aligned to prevent binding of the drawer within its supporting structure, the bracket comprising a first mounting plate adapted to be affixed to the drawer-supporting structure and including a nut member slidably mounted thereto to provide vertical movement, and the bracket comprising a second mounting plate having a horizontal slot adapted to receive a bolt therethrough for engagement with the vertically adjustable nut member, the second plate having a keeper member formed thereon to mount a drawer-guide member.

1. Field of the Invention
This invention relates generally to drawer-guide systems to allow drawers and the like to readily slide between an opened and closed position, and relates more particularly to an alignment device whereby a guide system can be aligned to prevent drawers from binding.
2. Description of the Prior Art
As is well known in the art, various problems and difficulties are encountered in providing a drawer-guide system with suitable means for aligning the related guide bars and supporting structure, so that the associated drawer will not bind from being misaligned.
There are many types and designs of drawer-guide systems. One type uses a central guide bar that is affixed between the rear portion of a drawer-support structure (herein referred to as a cabinet) and the front cross-bar. This type of slide is known as a single-track center-mounted drawer slide that incorporates the use of a rear-guide plate which is securely anchored to the rear portion of the drawer. The rail member of the slide is mounted to a rail socket, thus securing the rail to the rear of the cabinet, the front end of the rail being affixed as mentioned to a cross-bar. The rail at this time should be fixed within the cabinet, and aligned in parallel relation with the sides of the cabinet.
However, the aligned accuracy of the centrally positioned track is not always possible; and thus very often it must be adjusted when the complete cabinet unit is installed. This has been a well established problem in the installation of kitchen and bathroom cabinets in residential construction, etc.
There are other types of dual slide-bar mechanisms; and the same problem occurs with these also. Hence, there is a need for a simple adjustable bracket that can be adjusted at the time a drawer is positioned in the cabinet, without the need for repositioning the track of the supporting brackets.

Alignment bracket for drawer-guide systems


A glazing unit, including a composite glazing panel having a pair of vitreous sheets positioned parallel to one another and having respective marginal portions which face one another; an intervening layer which is comprised of polymeric material, which is sandwiched between the pair of vitreous sheets, and which has viscoelastic properties such that the composite glazing panel has a critical frequency of coincidence (or a lower or lowest critical frequency of coincidence if there is more than one), (.phi..sub.p) , which is greater than a critical frequency of coincidence of a notional monolithic vitreous sheet, (.phi..sub.m), the notional monolithic vitreous sheet having a shape and an area which are the same as that of the composite glazing panel and having a mass which is equal to the total mass of vitreous material in the composite glazing panel, and an adhesive material which is in contact with each vitreous sheet of the pair of vitreous sheets at at least the respective marginal portions thereof, and which is in contact with an outer face of at least one vitreous sheet of the pair of vitreous sheets at a marginal portion thereof, wherein the adhesive material exhibits, at 20.degree. C., an elongation of not more than 12.5% when subjected to a tensile stress of 0.1 MPa, as measured according to ISO 8339.

1. Field of the invention
The present invention relates to a glazing unit comprising a composite glazing panel having a pair of vitreous sheets adhered to an intervening layer of polymeric material sandwiched therebetween.
A glazing panel which consists of or includes a pair of vitreous sheets adherent to an intervening layer of polymeric material, is referred to herein as a composite panel.
References to acoustic properties of composite panels throughout this specification are references to such properties measured in accordance with the German Federal Republic Standard VDI 2.719.
2. Description of the Related Art
It is known from British patent specification GB 2227207-A (Glaverbel) to provide a composite glazing panel which consists of or includes a pair of vitreous sheets adherent to an intervening layer of polymeric material, wherein the sheets of said pair are separated by a said intervening layer of polymeric material which layer has viscoelastic properties such that the critical frequency of coincidence (or the lower or lowest critical frequency of coincidence if there is more than one) of the panel ["the coincidence frequency (.phi..sub.p) of the panel"] is greater than the critical frequency of coincidence of a notional monolithic vitreous sheet ["the coincidence frequency (.phi..sub.m) of the equivalent monolith"] which monolithic sheet is of the same shape and area as the panel and has a mass equal to the total mass of vitreous material in the panel.
Such a composite panel as is known from British patent specification GB 2227207-A (Glaverbel) referred to above, has, by virtue of the nature of its interlayer, improved acoustic insulating properties as compared with an otherwise similar composite panel which does not have such an interlayer. A composite panel may be installed in a building, or in a vehicle. One use for which composite panels are especially suitable is as glazings for railway carriages, particularly those of underground railway systems or of high speed transit systems where for one reason or another, ambient noise levels may be rather high.
The present invention has especial reference to the use of such composite panels in double-glazed units, the composite panel having acoustic attenuation properties. Hollow glazing units can have very good acoustic insulation characteristics, and they also afford good thermal insulation.
The commercial demand is more and more to install the panels in glazing bays by adhesively securing the panels to the support structure instead of mounting the panels in a chassis having a U-section profile, in which the edges of the panel are retained. This recent technique of panel installation is often referred to as "exterior panel adhesive fixing" or (somewhat improperly) as "structural glazing". This technique allows one to form facades which appear to be totally glazed. It also allows one to install the panels in a flush manner with the body-work of a vehicle for example. This technique allows one to obtain advantageous aesthetic effects.
There are two general methods possible for the manufacture of such units. Firstly, the composite panel may be assembled together with a frame in the factory and then the assembled unit is secured in position at the building site or vehicle construction works, depending on the intended use of the unit. Alternatively, the unit is assembled directly at the building site or vehicle construction works, where the unit is fixed to a frame or to the supporting structure rather than being retained in a U-section chassis.
At an elevated temperature such as about 50.degree. C., for example in sunshine, the intervening polymeric material of the composite panel has a tendency to flow, since its modulus of elasticity generally varies with temperature. The external sheet of vitreous material, which is held to the rest of the structure by the intervening polymeric material therefore tends to become loose and may even fall out of the structure.

Glazing unit and a method for its manufacture


A power supply applied to an electronic device for providing power includes a transformer unit, a connector, a pulse-width modulation (PWM) control unit, and a switch unit. The connector is electrically connected with the secondary side of the transformer unit for outputting a first output voltage. The PWM control unit outputs a pulse signal with a first period. The switch unit is electrically connected between the PWM control unit and the primary side of the transformer unit. When the electronic device is connected to the power supply, the connector receives an external control signal, and the PWM control unit adjusts the pulse width of the pulse signal to a second period and transmits the pulse signal with the second period to the switch unit to control the connector to output a second output voltage to the electronic device.

1. Field of Invention
The disclosure relates to a power transformer and, in particular, to a power supply.
2. Related Art
As the popular of portable electronic devices, the applications of the adaptors or chargers with USB connectors are increasing. Regarding to the current specifications, the standard output spec of USB2.0 is 5V/0.5 A, and the standard output spec of USB3.0 is 5V/0.9 A. The output spec of the cell phone charger using USB2.0 is generally 5V/1 A, or up to 5V/2 A. Accordingly, the maximum output power of a single USB connector is about 10 W.
Besides, when the adaptor or charger uses the USB port and outputs the power voltage, it cannot provide higher power voltage/current (less than 5V, 2 A) to the external electronic device due to the limitation of the available current or voltage output (must follow the USB specifications). Thus, the application of the adaptor or charger is restricted.


Disclosed is a synchronizing signal switching system for synchronizing operations of a plurality of disk devices without stopping the system operation even when a currently used synchronizing signal is stopped or deviated from standard. To this end, each disk device comprises a disk unit and a synchronizing signal switching unit for generating a synchronizing signal to be supplied to the disk unit. One of the disk devices is a current master disk device for currently supplying a master synchronizing signal and another one of the disk devices is a next master disk device. The disk devices are connected in a sequence to form a loop through which the master synchronizing signal is transmitted. The synchronizing signal switching unit in each of the disk devices is provided with an inheritance order to become the current master disk device or the next master disk device. When the current master synchronizing signal is deteriorated, the synchronizing signal switching unit having the next inheritance order is switched to supply the synchronizing signal as the current master synchronizing signal to all of the disk devices through the loop.

(1) Field of the Invention
The present invention relates to a synchronizing signal switching system for synchronizing operations of a plurality of disk devices in accordance with a master synchronizing signal, and more particularly to a synchronizing signal switching system that automatically switches a supply of, a master synchronizing signal from a particular disk device to another disk device, when the particular disk device stops to provide the master synchronizing signal or when the frequency of synchronizing signals contained in the master synchronizing signal deviate from a standard.
In a computer system connected to a plurality of disk devices for external storage, operations such as parallel data transferring operations of the disk devices must be synchronized. Namely, a plurality of disk devices are controlled by a host controller so as to synchronize not only the rotating speed of all of the disk devices but also the phases of the sectors in all of the disk mediums in the disk devices, for effecting parallel data read/write operations on the plurality of disk devices. To effect the synchronization, a particular one of the disk devices is preselected as a master synchronizing signal generating source, i.e., a master disk device, by supplying a control signal from the host controller or by manually setting switches provided on the disk devices. The thus preselected master disk device generates a master synchronizing signal with at least one index pulse corresponding to one rotation of the disk medium. The master synchronizing signal is supplied to all other disk devices for the synchronization.
When the master synchronizing signal is stopped or distored during working of the system due to some accident or problem, the system must conventionally be stopped in operation, and another disk device must be set as a new master synchronizing signal generating source. It is desirable, however, to continuously supply the master synchronizing signal without stopping the system.
(2) Description of the Related Art
Conventionally, a computer system, which involves a plurality of disk devices for external storages, employs a synchronizing signal to synchronize the rotation speeds of spindles of the disk devices and to synchronize the phases of sectors provided on the disk mediums to effect parallel data transfer. Namely, a master synchronizing signal is employed for synchronously controlling the rotation speeds of spindle motors of the disk devices and for coinciding the sectors on the disk mediums in different disk devices so as to enable parallel read/write operations on the plurality of disk devices. To this end, a host controller for the external storage devices includes a master synchronizing signal generating circuit from which the master synchronizing signal is supplied to the other disk devices. Alternatively, each of the disk devices may have a master pulse generating circuit, and a selected one of the disk devices is determined as a master pulse generating disk device by manually setting dip switches mounted on the disk devices, and in this case, the master synchronizing signal generated from the selected one of the disk devices is supplied to the other disk devices.
In such a conventional method to supply the master synchronizing signal, however, the disk devices and the sectors therein will not be synchronized once the master synchronizing signal is stopped or the master synchronizing signal is distored or deviated from the standard for some reason. If the stoppage or the distortion of the master synchronizing signal happens, the system operation must conventionally be stopped, and another disk device must be determined as a new master pulse generating disk device, or the master pulse generating circuit in the host controller must be replaced by a new one. Such stoppage of the system operation is a problem in the conventional art.

Synchronizing signal switching system for synchronizing external storage devices


A method of using a pipe machining apparatus according to an aspect includes providing a frame capable of being mounted onto a pipe, a tool carrier coupled to and movable relative to the frame, a tool support coupled to and movable with the tool carrier relative to the frame, and a laser line generator tool mounted on and movable with the tool support. The laser line generator tool images a laser light onto the pipe to align with a mark(s) on the pipe which denotes a proper cut line around the pipe. The apparatus can be repositioned relative to the pipe in order to enable an operator to properly position the apparatus on the pipe prior to a cutting operation.

A variety of different types of pipe machining apparatuses exist to perform various machining processes on pipes. One such process includes cutting pipes. Large diameter pipes may be cut with a split frame pipe machining apparatus, which includes two frame halves that surround the pipe from respective sides and are coupled together around the pipe. Such a pipe machining apparatus includes a cutting tool that encircles the pipe and moves toward the pipe in small increments during a cutting process in order to slowly cut into the pipe. Eventually, after many small increments of adjustment toward the pipe, the pipe will be completely cut.

Method of using laser line generator tool of a pipe machining apparatus


A control circuit is used in an apparatus such as a printer in order to detect status and conditions of the apparatus. The control circuit includes a main control board and a plurality of sensor boards. The sensor boards are connected in cascade to define a signal path that run through the plurality of sensor boards. Each sensor board is connected to a corresponding sensor that detects a status or condition in the apparatus, and provides a sensor output of the corresponding sensor to the signal path. When the main control board provides an activation signal to the first one of the plurality of sensor boards, each sensor board provides the corresponding sensor output onto the signal path at a predetermined timing. The sensor boards provide their sensor outputs in the order in which their are cascaded. The main control board receives the sensor output at the predetermined timing, the sensor output signal being output in an order in which the plurality of sensors are connected in cascade.

1. Field of the Invention
The present invention relates to a control circuit for use in information processing equipment such as facsimile machines and printers.
2. Description of the Related Art
Information processing equipment such as facsimile machines and printers have a variety of sensors and switches incorporated therein. Such sensors include sensors that detect the presence and absence of recording paper and an original, and reflection type sensors that detect the positions of moving recording paper. Signals from a large number of sensors and switches mounted at various locations in the equipment are directed to corresponding input terminals of the I/O port over individual wires, and are directed to the CPU via the I/O port.
Therefore, a large number of cables and wires are used in the equipment and present design problems such as difficulty in routing wires, increasing assembly time, and obstacles to troubleshooting.

Control circuit with cascaded sensor boards


A method includes coupling, at least temporarily, a support member adjacent to a target tissue. The support member is configured to support the target tissue and to define a path along which a cutting device can move. The method includes moving the cutting device along the path defined by the support member to cut and/or dilate the target tissue. In some embodiments, the method optionally includes disposing a cannula of a device within the cut defined in target tissue. The cannula is coupled to the target tissue such that a lumen defined by the cannula is in fluid communication with a volume defined at least in part by the target tissue.

The use of devices to assist the function of an ailing heart is increasing. In some instances, a ventricular assist device (VAD) can be used to partially or completely replace the function of the heart. For example, in some instances, a left ventricular assist device (LVAD) can be used to assist a heart of a patient by placing an inlet flow cannula in fluid communication with the left atrium of the heart and an outlet flow cannula in fluid communication with a portion of the aorta. The LVAD can include a pumping mechanism that can pump, transfer, draw, push, or otherwise produce a flow of blood between the inlet flow cannula and the outlet flow cannula, thereby assisting heart.
Some known methods for placing an inlet flow cannula in or at a desired location within, for example, the left atrium include advancing the inlet flow cannula through the superior vena cava (SVC) and piercing the septum between the right atrium and the left atrium. In such methods, the thickness of the septum can be sufficient to allow piercing and/or cutting thereof to provide the passage of the inlet flow cannula. Such methods, however, often include an at least partially blind piercing of the septum, which can be challenging and can result in undesirable placement of the inlet flow cannula. Some such methods can be used with imaging techniques such as, fluoroscopy and echocardiography, however, due to the distance between the insertion point and the target location of the heart and/or the torturous path of the anatomy, precision can still be difficult and the ability to apply a suitable force can be challenging.
In other instances, methods for placing an inlet flow cannula in or at a desired location within the left atrium include coupling the inlet flow cannula to the dome of the left atrium. This location can provide performance benefits because it is adjacent a wider portion of the left atrium and is remote from the left and right pulmonary veins. Coupling of the inlet flow cannula to the dome of the left atrium, however, can be complicated by the anatomy of the heart. For example, the walls of the dome of the left atrium are very thin (e.g., between 1 and 2 mm in thickness) and fragile, which can make incising the tissue difficult. Moreover, certain procedures may include dilating an incision in the atrial wall with a dilator and/or balloon catheter, for example, to accommodate the desired size of the inlet flow cannula. Dilation of certain tissue, such as the dome of the atrium can lead to tearing of the tissue and/or fracture that can extend beyond a diameter of the dilator (e.g., due at least in part on the thinness of the tissue). In addition, the interior of the atrium can be at a relatively low pressure, due to the function of the heart. Therefore, when the dome of the left atrium is pushed and/or manipulated from the outside to incise or dilate the tissue (e.g., with a scalpel or other tool), the tissue can collapse into the atrium, making a clean cut of the atrium wall difficult to achieve. In some instances, similar collapse can occur in, for example, transseptal puncture and/or a puncture through the right atrial wall.
Thus, a need exists for improved apparatus and methods for cutting target tissue and inserting a cannula of a ventricular assist device into the left atrium of a heart.

Apparatus and methods for cutting an atrial wall


A closure for an elongated skin wound having a pair of edges has a pair of parallel tapes each formed by a U-shaped one-piece textile outer strip having a longitudinally extending outside flap and, parallel thereto, an inside flap joined at a longitudinal fold, and a filler strip extending longitudinally between and spacing the flaps apart. Each tape has an inner edge turned toward the other tape and carrying one of a pair of longitudinal rows of interleavable teeth on the outside flaps. Stitches or the like engaged through the flaps and filler strip of each tape hold them together. A skin-compatible adhesive adhered to inside faces of the inside flaps allows the inside flaps to be adhered to skin to each side of the wound. A slider displaceable longitudinally along the rows of teeth can interleave and couple them together so that, when the tapes are adhered to skin to each side of the wound, coupling the rows of teeth with the slider pulls the edges of the wound together.

A typical such closure comprises a slide fastener consisting of two textile support tapes carrying rows of interleavable coupling members that can be joined by a slider. The tapes are adhered to the patient's skin to either side of the wound or incision with the slider down and the teeth not coupled, then the slider is drawn up to pull the lips of the wound together. Thus this closure is not intended to cover the wound, but instead serves to pull the sides of the injury together so that they can knit and heal. Although it is used most easily on a straight surgical incision, it can also be applied to S-shaped or curved wounds, lacerations, contused wounds, and the like.
Such a system is described in U.S. Pat. No. 4,881,546 of H Kaessmann. In it the slide fastener is a conventional flexible fastener of the kind used for textile garments, insofar as concerns the rows of coupling members and the support tapes which are of low elasticity and the rows of coupling members which consist of polyester or polyamide and are resistant to compression in the closed state. Spacer strips which form a wound-space zone are disposed on the support tapes at a spacing from the rows of coupling members, on the under side facing the wound. The adhesive connection is made by adhesive strips connected to the support tapes and projecting therefrom. These strips have a skin-compatible adhesive coating on the skin side. The support tapes are backed by the adhesive strip over at least part of their width. The adhesive strips including the projections have a width suitable for taking the transverse tensile forces in the case of the wound being closed by the slide fastener and having abutting wound edges, i.e. the wound edges are pressed against one another. The known device has proved satisfactory and meets all requirements medically, but in terms of manufacture it is expensive, a feature which is particularly disturbing inasmuch as these devices are mass-production products.