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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a hybrid clean-energy power-supply framework, particularly to a hybrid clean-energy power-supply framework that integrates a fuel cell, photovoltaic, and wind energy into green-energy.
2. Description of the Prior Art
In recent years, developing alongside a global rise in environmental consciousness and the problem of greenhouse effect brought by carbon dioxide pollution, the application of renewable energy becomes a noticeable issue and the sustainable development concept further becomes the major motive force of clean-energy promotion.
A fuel cell, dependent on an electrochemical reaction to generate electrical energy without combustion, using hydrogen and oxygen to produce an electron flow for generating an electrical current, water, and heat, produces almost no pollution. The function of a fuel cell is similar to a battery but different, that is, electricity generated by a fuel cell neither runs exhausted nor need to be charged if fuel sufficient. Because electrical energy of a fuel cell can be generated on condition that a fuel presents, a fuel cell is a kind of energy conversion apparatus, therefore problems of the service life of periodical recharge limited and abandoned batteries bringing the environmental pollution of a conventional battery, can be eliminated. Therefore, problems of the service life of rechargeable batteries and abandoned batteries, that may cause environment pollution, can be eliminated. If the fuel cell has a converter for converting a natural gas or other fuel into hydrogen, then those fuels can be used in a fuel cell. Therefore the present invention, collocated with an electrolyzing system to directly obtain hydrogen and oxygen from water, no need to obtain hydrogen from other fuel such as a natural gas, is completely self-sufficient and thus achieves the object clean energy.
Solar energy is the largest energy source in the solar system and due to the advancement in the conversion efficiency of a solar cell and great progress in the semiconductor industry, both cause the continual lowering of the cost of a solar cell, and thus the economical practices of solar energy is emerging. Since Taiwan is located in the subtropical zone, in plenty of light, suitable for the development of solar energy, stable illumination can provide stable power output, and the equipment maintenance is easy, thus solar energy will become a primary power source in the future.
Wind-power is a renewable energy with less pollution and some nations abundant in wind resources already have been setting forth a lot of development, particularly belongs to a green-electricity, and supported by more people, the capacity installed is increasing recently and thus creates remarkable contributions on world energy development and environmental protection.
At present, the cost of the above-mentioned power generation facilities are still high and because a rise in environmental consciousness and each nation in the world is continuously promoting and encouraging development with installation subsidy, facilitated by constant R&D, the speed of cost reduction is accelerated. Reportedly, the cost of wind-power already was reduced below NT$2.0/KWH. As regards the price of the fuel cell and photovoltaic are still much higher than the utility power, however, when the utility power demand grows larger and the manufacture technology advances and mass production of green-power is available, approaches to the price of conventional power generator can be looking forward. Based on the forecast that the power-cost will balance the cost of equipment, fuel, and maintenance in the future, the present invention integrates a clean-energy power-supply systems to facilitate promoting usefulness thereof.
The power characteristics of those three above-mentioned power generating system have highly nonlinear relationships. At present, a device of feeding a single system into a utility power has been developed, but it is not considered a mechanism for feeding those three systems into the utility power together. Moreover, a function, which is designed in the sense of the cost oriented and economical dispatching rule for controlling the generating capacity of those three systems to ensure stable and contingent electricity, is still investigated poorly in the previous works.
Accordingly, it can be seen that the above-described conventional technique still has many drawbacks, and is not designed well, and urgently needs improvement.
In view of the disadvantages derived from the above-described conventional ways, the present inventor had devoted to improve and innovate, and, after studying intensively for years, developed successfully a hybrid clean-energy power-supply framework according to the invention.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a hybrid clean-energy power-supply framework, using a central processing unit to monitor and dispatch each of the power generating and supply systems, calculating accurately the system capacity, determining an optimal generation model, ensuring the reliability of power-supply and reducing the cost of power generation.
The other object of the present invention is to provide a mechanism for a selectively grid-connected or stand-alone power-supply system that is capable of preventing island effect. When the utility power is normal the grid-connected with utility power is selected and once the utility power is interrupted, isolating the utility power and dispatching load, the power-supply of partial loop is continued.
The hybrid clean-energy power-supply framework that can achieve the above-mentioned objects of the present invention is a hybrid clean-energy power-supply framework that integrates a fuel cell, photovoltaic, and wind-power energy. The fuel cell, applying the electrochemical reaction principle, using hydrogen and oxygen as reactants, produces merely pure water, direct current, and waste heat; all such three products are usable resources and the whole process does not produce any pollution and thus is an environmental-protection power generating device; a solar cell uses the photovoltaic effect to convert luminous energy into electric energy, useful solar cells all use silicon having better photoconductivity as the primary material and photovoltaic energy is clean, has no-pollution, and the energy resources are available easily, and it is never exhausted, thus it also is an environmental-protection power generating device; wind-power energy, using electromagnetic principle, specific-structure fan leafs are pushed by wind force to drive the rotator of a DC generator turning for generating direct current, is a clean, no-pollution, and does not require laborious exploitation, is an environmental-protection energy resource supplied by nature directly. In order to match up the power control and electricity dispatching, after all calculations are processed by a central processing unit of an electricity monitoring system, the electricity monitoring system controls the step-up of each power generating system to DC bus such that electricity can be fed into the AC utility power, via an energy conversion system, and supply load.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings disclose an illustrative embodiment of the present invention that serves to exemplify the various advantages and objects hereof, and are as follows:
FIG. 1 is a block diagram of a hybrid clean-energy power-supply framework according to the present invention;
FIG. 2 is a flow chart of a hybrid clean-energy power-supply framework according to the present invention;
FIGS. 3( a ), ( b ), and ( c ) are the schematic diagram of an embodiment of a hybrid clean-energy power-supply framework according to the present invention;
FIG. 4 shows an energy conversion system diagram of an embodiment of a hybrid clean-energy power-supply framework according to the present invention; and
FIG. 5 is a schematic diagram of an apparatus for electrolyzing water into hydrogen and oxygen of an embodiment of a hybrid clean-energy power-supply framework according to the present invention;
FIG. 6 is a block diagram of the distributing disc of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a block diagram of a hybrid clean-energy power-supply framework according to the present invention. Said power-supply system includes an interface for feeding utility power. A general high-voltage client, stepping down the utility power in a transformer of a self-installed distribution substation to get a low-voltage feeder 101 for distribution, through a distributing disc 102 , allocates shunts to each load. FIG. 6 shows the distributing disc 102 that comprises: a no-fuse breaker for preventing the conductive wire of the shunt from short-circuit; an electromagnetic switch for controlling the coil of said electromagnetic switch to make/break a shunt thereof and a control signal thereof touch-controlled by a digital switch of a central processing unit; a potential transformer (P.T.) and a current transformer (C.T.) for sending the sensed voltage and current of a shunt to a central processing unit for calculation. The distributing disc 102 has functions for protecting shunt lines and isolating the utility power and power load 103 , thus the electric energy generated by a hybrid clean-energy power-supply framework according to the present invention can be fed from the distributing disc 102 . A signal, detected by a current transformer and a voltage transformer of said distributing disc 102 , is used as a base for power control. At the same time, it can achieve load control and isolate the utility power loop to avoid the island effect by way of controlling the electromagnetic switch to make/break a load loop, In addition, it can prevent the overload phenomena of the hybrid clean-energy power-supply system owing to the interruption of the utility power. The power load 103 is defined as the internal load supplied by a hybrid clean-energy power-supply system, and is also the measurement of power quantities in the present invention.
The electric energy of a hybrid clean-energy resource comes from hydrogen energy, solar energy and wind energy. Hydrogen energy is made from an electrolyzing system 104 , oxygen storage system 105 , hydrogen storage system 106 , and a fuel cell power generating system 107 . Hydrogen and oxygen are electrolyzed from water in the electrolyzing system 104 , and are subsequently sent to the oxygen storage system 105 and the hydrogen storage system 106 respectively. The required power for electrolyzing water comes from the clean-energy surplus and the night off-peak cheap power. The hydrogen of a hydrogen storage system 106 is the primary fuel of said fuel cell, using catalytic materials such as platinum, silver, nickel, and the like to separate electrons in the hydrogen gas and bring electrons to a load port. Thus a power generating system with an electron flow is formed. The oxygen in the oxygen storage system 106 is a combustion supporting gas required by the chemical reaction in the fuel cell power generating system 107 , and the proportion required is smaller than hydrogen gas. After the power generating process is completed the surplus oxygen can be stored for sale to reduce the power generating cost indirectly. The electric power of a photovoltaic system 108 and a wind power generating system 109 are prioritized to feed the electricity required by the power load 103 in the utility power. If surplus power remains then all are provided to the electrolyzing system. The three above-mentioned power generating systems must step up the DC bus of the direct voltage respectively and then transfer power to an energy conversion system 110 . The energy conversion system 110 , using the pulse width modulation switching mechanism, via a full-bridge converter framework, converting the direct voltage into a sinusoidal voltage with the utility power frequency, thus achieves the objects for controlling the power of feed-in utility power and raising the power factor. An electricity monitoring system 111 , as the control center of the present invention, comprises a section for electricity monitoring and protection and another for electricity economical dispatching. The former, is the utilization of the digital signals transformed from the analog signals of voltage and current sensed from each unit for monitoring display data and protecting the system operation at normal. Moreover, the latter is the calculation of current commands in a central processing unit via the voltage and current signals of each loop for controlling each power generating system and the energy conversion system so that the power flow can be determined.
FIG. 2 shows a flow chart of a hybrid clean-energy power-supply framework according to the present invention. In a photovoltaic system 108 , the generating capacity is directly proportional to the amount of insolation. It has no fuel cost and the useful power can be extracted via a max power tracking control mechanism. The output dc voltage of a solar cell is inversely proportionate with its output dc current. Because the output power is the product of voltage and current in a dc system the max power is the max value of those products. In the tracking control process, because the product of the voltage of a solar cell and the current to be controlled needs to be calculated and must be detected at any time, a lot of on-line data needs to be calculated by a central processing unit with heavy load, and if the control is unstable, the power consumption of an institution will increase and the object for achieving the max power control can not be obtained. Fortunately, at present some methods are disclosed continually that can effectively achieve the max power tracking control comprising: voltage feedback method, power feedback method, perturbation and observation method, incremental conductance method, linear approximation method, actual measurement method, etc. A wind power generating system 109 , wherein the output power of a wind-power generator is proportional to the cube of wind speed and the square of the voltage, rotary speed descending while extracted current increased, has a problem of max power tracking control similar with the solar cell, and thus, can be solved by the above-described methods.
Most of the flow chart shown in FIG. 2 relates to the processing of the power balance and economical dispatching of minimum power generating cost. After completing the max power tracking control, the sum P G of P S , which is the output power of a photovoltaic system 108 , and P W , which is the output power of a wind power generating system 109 , presents the generating power at no-fuel cost, is fully fed into the utility power, but the surplus power P E is used to start the electrolyzing system 104 , if the sum P G is greater than the power P L of the power load 103 . There are two reasons why the surplus power P E does not feed into the utility power by an inverse flow: first, rules and clauses in the Electricity Laws of Taiwan, R.O.C., about feeding the utility power through an inverse flow, has not yet been revised. Thus, the power plant does not have a legal basis for pricing. Second, the over-contract extra charge of the power plant is 2 or 3 times higher than the demand charge, in another words, the over-contract extra charge/15 min/kW is NT$600 or more, 1000 times higher than the energy charge of the same time. Therefore, in order to reduce the over-contract extra-charge, the fuel cell power generating system 107 suppresses the peak power not over contract and further reduces the contract capacity and expense thereof, that is not less the expense of energy charge reduced. Accordingly, increasing the hydrogen storage and oxygen storage can suppress more peak power.
Further, the night off-peak charge only is 10% of the peak charge, so preferably the off-peak utility power is used to electrolyze water and the daytime utility power is outputted from the fuel cell power generating system 107 . During the time period of peak utilization, when the power P T of the utility power from the low-voltage feeder 101 of the power plant is larger than the contract capacity, the fuel cell power generating system 107 is started and the generating power thereof is calculated by a central processing unit of an electricity monitoring system 111 , using the history data of the power load 103 to forecast the over-contract amount and the over-contract interval, checking hydrogen storage, to obtain an optimal economical dispatching power. The object of obtaining an accurate calculation is to achieve suppressing peak utilization in order to not exceed the contract capacity at any time. Otherwise, if the average utilization over the contract capacity occurs for 15 minutes just once in a month, then the benefit previously obtained from suppressing the peak utilization will be erased. Furthermore, the capacity of a fuel cell power generating system 107 and a hydrogen storage system 105 may not be enough to suppress the utilization below the contract capacity, therefore averaging the peak utilization may still exceed the contract capacity, but can keep the utilization constant.
Electricity must be released if the capacity of the hydrogen storage system 106 has been saturated. When the cooler is stopped in winter or the utilization is lower on holiday, in less over-contract case, the fuel cell power generating system 107 can be outputted with max generating power P F(max) until hydrogen storage consumed to the safety stock thereof in peak pricing time phase. And the surplus gas of the oxygen storage system can be sold to increase additional revenue. On the whole, the fuel cell power generating system 107 produces hydrogen using the cheaper electricity at night, and thereafter uses the same hydrogen to generate electricity during the day in order to reduce the peak energy charge and over-contract charges. Even after deducting the losses due to the chemical recycle reaction, the system still has a profit.
FIG. 3 shows an embodiment of a hybrid clean-energy power-supply framework according to the present invention. FIG. 3( a ) shows a fuel cell power generating system, FIG. 3( b ) shows a photovoltaic system, and FIG. 3( c ) shows a wind power generating system. Because the location to install the power generating systems are separate from the distributing disc 102 , the solar cell must be installed on the roof, the wind driven power generator 307 installed outside of the house mostly, and the power transmission line should be long enough to integrate those three power generating systems. In order to reduce the power transmission loss, there is a need to step up the stable direct voltage most near the power generating system. The direct voltage power transmission line is better than an AC power transmission system and has several advantages such as no skin effect, no electromagnetic interference, less power transmission loss, no inductance constrained max transmission power, etc. Furthermore, Occident's response to the power transmission problem of renewal energy gradually reaches a consensus to establish a voltage specification of high-voltage DC bus. All converters in those three power generating system, the DC booster and converter circuit 303 of a fuel cell 301 , the DC booster and converter circuit 306 of a solar cell, and the DC booster and converter circuit of a wind power generator 309 , are adjusted by an inductance current to achieve the object of power control. The output direct voltage of a power generating system is measured by a voltage sensor and is known data. This known data is multiplied by the output average current (conductance current) of the power generating system to be controlled, and this product is the output power of the power generating system. The circuit framework uses a booster-type converter, the cycle of the pulse width modulation (PWM) switching is D, the input and output voltage of the converter is V IN and V DC , then the voltage gain G V can be obtained from:
G V = V DC V IN 1 1 - D ( 1 )
The cycles D of switching of the converters of three power generating systems are determined, respectively, by the power tracking, flow control, and the driving circuit 302 of a fuel cell, by the max power tracking control and the driving circuit 305 of a solar cell, and by the max power tracking control and the driving circuit 308 of a wind power generator. Since the solar and wind energy must be extracted with the max power, there is a need to create a max power tracking control rule in a central processing unit, via calculating the sensed voltage signal outputted from a DC generating apparatus, to obtain a switching cycle D command. The max power tracking control and the driving circuit 305 of a solar cell further includes a sun tracking mechanism for controlling solar energy control plates perpendicular to the sun light to obtain the maximum amount of insolation. This part can be achieved by using a motor to elevate the system and an illuminometer for coordination. The maximum power tracking control and the driving circuit 308 of a wind power generator further includes: a windward mechanism for controlling the angle of wind-leafs and the excitation voltage so as to absorb the maximum mechanical energy. Because the fuel cell must consider factors such as the peak utilization, power generating cost, etc., the adjustment of the switching cycle D command varies with the utilization and generating power respectively. As regards the control of keeping the DC bus constant, the adjustment can depend on the feed-in utility power size, in other words, when the direct voltage is kept on a predetermined value, this shows the feed-in utility power equals to the total generating power of those three clean-energy systems. When the central processing unit receives a signal showing interruption, under-phase, or under-voltage of the utility power, the loop of the utility power in the distributing disc 102 is cut-off and isolated immediately and the output power of those three power generating system are calculated accurately. Then the load loop parallel in the distributing disc 102 is chosen, based on the emergency priority of supplying power, to adjust the output power P F of the fuel cell power generating system as a balance mechanism of power generation and utilization.
FIG. 4 shows an energy conversion system diagram of an embodiment of a hybrid clean-energy power-supply framework according to the present invention. The power calculation of the feed-in utility power 401 , which is a function of the electricity monitoring system 111 , contains the output power of all power generating systems and each loop power of the utility power to obtain the net output power of the power generating system. It sends this net output power signal to the control driving circuits of power factor correction and the feed-in utility power 402 . The power factor correction circuit can convert the direct current command of the feed-in utility power into an AC sync current command to control the four switch-driving signals of the inverter circuit 403 and force the inductance current of the LC filter 404 tracking the AC sync current command. If the voltage of the DC bus is kept at a predetermined value, this then indicates that the power generation and the power supply is in balance. Otherwise, if the DC bus voltage is larger, this indicates that the power generation is higher than the feed-in utility power; the feed-in utility power should be raised. When the phase of the sinusoidal current of the feed-in utility power is the same as the utility power ν AC , the reactive power is zero, power factor is 1, and thus can minimize the bus current of the hybrid clean-energy power-supply framework according to the present invention, improve the voltage wave, and further raise the overall efficiency of the energy conversion system 110 .
FIG. 5 shows a schematic diagram of an apparatus for electrolyzing water into hydrogen and oxygen of an embodiment of a hybrid clean-energy power-supply framework according to the present invention. In general, pure water is quite difficult to be electrolyzed, usually adding sodium hydroxide or sulfuric acid 505 to facilitate electric conduction, and using carbon rods or injection needle as electrodes. A positive carbon rod 501 is connected to the positive voltage of the direct voltage bus 506 ; a negative carbon rod 502 is connected to the negative voltage of the direct voltage bus 506 . As a direct current is introduced to the electrodes, OH ions in the water move to the positive electrode of the direct voltage bus 506 , and oxygen can be collected by the inlet of an oxygen collector 503 at the positive electrode and sent to the oxygen storage system 105 . But H + ions move to the negative electrode, where hydrogen can be collected by the inlet of a hydrogen collector 503 at the negative electrode and sent to the hydrogen storage system 105 . During electrolyzing, the higher voltage of the direct voltage bus 506 or the closer of two electrodes, the faster speed of producing bubbles from electrolyzing. Because the density of the hydrogen and oxygen produced is smaller than water and does not dissolve in water, the method utilizing such a feature to collect gas is known as the drainage gas-gathering method.
As compared with other conventional techniques, the hybrid clean-energy power-supply framework according to the present invention has the following advantages:
1. The present invention is a hybrid clean-energy power-supply framework, wherein using the favorable price of the off-peak utility power (from 10:00 pm to 7:30 am set in a dual meter), to electrolyze water to create hydrogen and oxygen for storage; because the peak energy charge is 1.5 times or more than the off-peak energy charge, starting the fuel cell to generate electricity during the daytime, that not only reducing energy charge (total utilization kWH×price/kWH), but also suppressing the peak utility power to reduce the over-contract charge about NT$316/kW to about NT$648/kW. Furthermore, the stored hydrogen can be used as a green gas battery for providing emergency electricity during the utility power interruption. The surplus oxygen can be sold for use in medical treatment or oxygen welding.
2. The present invention uses a fuel cell to replace a battery and can supply electricity continuously. The generating power of a solar cell and a wind power generator is subject to the environment, time, and climate. The amount of insolation, for example, is directly related to proximity to the equator, the higher illuminance, larger in the summer than in the winter due to longer days and sunshine time, but power generation obviously must stop at night. The wind power generator, installed along coastal regions, creates more electricity during northeast monsoon due to winds blowing from the north of Taiwan, the generating time is not limited to the daytime, but air flow is not stable and timing-easy as the solar illuminance. Summarizing the above, the generating capacities of the solar cell and wind power generator, has complementary relationship partially, that is, those two generating electricity tending to balance in various time phase or in different regions. However, the wind-power generating stops at night or when air flow ceases. The solution of a general stand-alone power-supply system is to add a battery for providing electricity continuously. When the depth of discharge is 100%, the average life of a lead-acid battery is about 300 times, the depreciation cost of this equipment is several times of the utility power, and more a battery has faults such as large volume, heavy weight, low storage capacity, and the environmental-protection problem after scrapped. Thus the above two power generating systems, although no need on fuel cost, once if using storage batteries, achieving the object and pragmatism of clean-energy is difficult.
Many changes and modifications in the above-described embodiment of the invention can, of course, be carried out without departing from the scope thereof. Accordingly, to promote the progress in clean-energy technology and the useful arts, the invention is disclosed and is intended to be limited only by the scope of the appended claims. | A hybrid clean-energy power-supply framework integrates a fuel cell, solar cell, and wind energy, applies a max power tracking rule, raises the output power of a solar cell and wind energy to supply a power load and transfer the surplus electrical energy to a water-electrolyzing apparatus for producing hydrogen and oxygen, and provides a fuel for a fuel cell power generating system. Furthermore, the present invention utilizes features of each clean-energy power generating system, depends on the powerful calculation capacity of a central processing unit to monitor and dispatch each power generation and supply system, and thus ensures the reliability of supply power and reduces the power generation cost. Such a framework can selectively grid-connect with the utility power or run as a stand-alone power supply system and has a mechanism for preventing the island effect. | 5 |
This is a continuation, of application Ser. No. 097,902 filed Nov. 28, 1979, now abandoned.
BACKGROUND OF THE INVENTION
This invention relates to a novel class of organosilanes. The characteristic feature of these silanes is the presence of a hydantoin residue that is bonded to silicon through an alkylene group.
SUMMARY OF THE INVENTION
The organosilanes of this invention exhibit the general formulae ##STR1## wherein R 1 is selected from the group consisting of alkyl, aryl, cyanoalkyl, trifluoropropyl, alkenyl, alkynyl and halophenyl; R 2 is selected from the group consisting of alkyl, alkaryl and cycloalkyl; R 3 is alkylene; R 4 and R 5 are individually selected from the group consisting of hydrogen, alkyl, aryl, aralkyl and alkaryl; R 6 is ##STR2## or is selected from the same group as R 4 and n is 0, 1, 2 or 3 with the proviso that any alkyl or alkylene group contains from 1 to 12 carbon atoms and any alkenyl or alkynyl group contains from 2 to 12 carbon atoms.
This invention also provides a method for preparing a hydantoinyl silane, said method consisting essentially of the following steps:
(1) Reacting substantially equimolar amounts of (a) an anhydrous alkali metal salt of a hydantoin represented by the general formula ##STR3## wherein M represents an alkali metal and (b) a haloalkylsilane represented by the general formula ##STR4## in a reaction medium comprising a dipolar, aprotic liquid;
(2) maintaining the mixture containing the hydantoin salt and said haloalkylsilane at a temperature of from ambient to the boiling point of said mixture for a period of time sufficient to obtain a substantially complete reaction, and
(3) isolating said hydantoinyl silane from the reaction mixture.
DETAILED DESCRIPTION OF THE INVENTION
The novel silanes of this invention can be prepared using conventional procedures employed for reacting halosilanes with compounds containing a labile proton. A preferred method involves the reaction of an anhydrous alkali metal salt of hydanotoin or one of the substituted hydantoins represented by the formula ##STR5## with a haloalkylsilane represented by the formula ##STR6## wherein X represents chlorine, bromine or iodine. This reaction is preferably conducted in the presence of a dipolar aprotic organic liquid medium which is a solvent for the aforementioned alkali metal salt of the hydantoin. Suitable dipolar aprotic liquids include N,N-dimethylformamide, N-methylpyrrolidone and dimethylsulfoxide.
Since the reaction between the hydantoin salt and the haloalkyl silane may be exothermic, it is preferable to first dissolve the hydantoin salt in the liquid reaction medium and gradually add the haloalkylsilane to the resultant solution under an inert atmosphere such as nitrogen to exclude even trace amounts of water, which would rapidly hydrolyze the alkoxy groups present on the haloalkylsilane. It is often desirable to heat the reaction mixture at temperatures of from 40° to about 100° C. for from 0.5 to 5 hours or longer to ensure that the reaction is complete. The reaction product is often soluble in the reaction medium, in which instance the product is readily isolated by filtering to remove the solid alkali metal halide byproduct and distilling the dipolar aprotic liquid under reduced pressure to minimize heat-induced decomposition of the desired product.
The product of the aforementioned reaction contains one silicon atom and one hydantoin residue that is bonded to silicon through an alkylene group represented by R 3 in the foregoing formula. Compounds containing 3 hydrocarbyl and 1 hydrocarbyloxy group bonded to silicon are readily converted to the corresponding bis(hydantoinylalkyl)tetrahydrocarbyldisiloxane by hydrolysis in the presence of a methanol-water or ethanol-water mixture containing a trace amount of an alkali metal hydroxide such as potassium hydroxide.
THe hydantoin employed to prepare the compounds of this invention can be unsubstituted, in which instance the substituents represented by R 4 , R 5 and R 6 in the foregoing formulae are hydrogen. Alternatively, one can employ any of the available substituted hydantoins or a compound containing the desired substituents can be prepared using synthetic procedures and reactions disclosed in the chemical literature. Representative substituted hydantoins which are commercially available or have been reported in the chemical literature include
5,5-dimethylhydantoin
5,5-diphenylhydantoin
5-ethyl-5-(2-methylbutyl)hydantoin
5-phenylhydantoin
The synthesis of hydantoin, also referred to as 2,4-diketoiminazolidine, and a number of substituted hydantoins, is described in a text entitled "Chemistry of Carbon Compounds" edited by E. H. Rodd (Elsiner Publishing Company, 1957) and in an article by E. Ware [Chemical Reviews 46, 403-470 (1950)].
The following examples describe the preparation of 4 preferred species selected from the present class of novel silanes and disiloxanes. These examples should not be considered as limiting the scope of the accompanying claims.
EXAMPLE 1--Preparation of 5,5-dimethyl-3-trimethoxysilylpropyl Hydantoin
A mixture containing 12.8 g (0.1 mole) 5,5-dimethylhydantoin, 5.6 g (0.1 mole) potassium hydroxide and 100 cc ethanol was heated to the boiling point until a clear solution was obtained. The ethanol was then evaporated under reduced pressure to isolate the solid, anhydrous salt. The salt was combined with 100 cc of dry N,N-dimethylformamide and the resultant mixture was heated at 50° C. until a clear solution formed. A 19.8 g (0.1 mole) portion of chloropropyl trimethoxysilane was then added dropwise to the aforementioned salt solution under a nitrogen atmosphere with stirring. The temperature of the reaction mixture increased slightly during the addition, which is indicative of an exothermic reaction, and a white precipitate (potassium chloride) began to form when the silane addition was begun. Following completion of the addition the reaction mixture was heated at 95° C. for three hours. Analysis by vapor phase chromatography of the liquid phase demonstrated that the initial chloropropyl trimethoxysilane had been converted to a product exhibiting a high retention time. The reaction mixture was then cooled and filtered, following which the liquid phase was distilled to remove the N,N-dimethylformamide. A second fraction was collected at a temperature of 194° C. and a pressure of 4 mm of mercury and subsequently solidified to a white solid. Analysis by vapor phase chromatography indicated that this material was 98% pure and contained a trace amount of the initial hydantoin. The infra-red spectrum of the material was consistent with the proposed structure ##STR7## The product was found to contain 9.74% by weight of silicon and 9.92% nitrogen. The calculated values for the expected product are 9.64% silicon and 9.66% nitrogen.
EXAMPLE 2--Preparation of 3-Dimethoxymethylsilylpropylhydantoin
A mixture containing 10.0 g (0.1 mole) hydantoin, 5.6 g (0.1 mole) potassium hydroxide and 100 cc ethanol was heated to the boiling point until a clear solution was obtained. The resultant salt was then isolated and dried as described in the preceeding example, following which it was solubilized in 100 cc of anhydrous N,N-dimethylformamide and reacted with 18.2 g of chloropropylmethyldimethoxysilane under a nitrogen atmosphere using dropwise addition. The reaction mixture was heated at 110° C. for about sixteen hours following completion of the silane addition. The reaction mixture was then cooled and filtered to remove the potassium chloride byproduct. Analysis of the liquid phase by vapor phase chromatography demonstrated that the original silane had been consumed and replaced by a material having a significantly longer retention time. The desired product was recovered following distillation to remove the N,N-dimethylformamide.
EXAMPLE 3--Preparation of Bis[5,5-dimethylhydantoin-3-yl)propyl]tetramethyldisiloxane
A sample of 5,5-dimethyl-3-dimethylmethoxysilylpropylhydantoin was prepared and isolated using the general procedure described in the preceeding examples with 0.1 mole of each of the three reagents, namely 5,5-dimethylhydantoin, 3-chloropropyldimethylmethoxysilane and potassium hydroxide. A 24.4 g portion of the final product was dissolved in a mixture of 5.4 g of water and 300 cc methanol containing one pellet of potassium hydroxide. The resultant mixture was stirred at ambient temperature for 16 hours, at which time the methanol-water mixture was removed by distillation under reduced pressure. The identity of the final product as a disiloxane was confirmed by its infra-red spectrum and by vapor phase chromatography.
EXAMPLE 4--Preparation of 1,3-Bis(trimethoxysilylpropyl)-5,5-dimethylhydantoin
A 2.4 g portion of a dispersion containing 50% by weight of sodium hydride in a liquid paraffin was added in portions under an inert atmosphere to a solution containing 14.5 g (0.05 mole) 5,5-dimethyl-3-trimethoxysilylpropyl hydantoin and 150 cc of anhydrous N,N-dimethylformamide. The temperature of the reaction mixture was maintained at from 15° to 20° C. during the addition of the hydride. Following completion of the addition the mixture was stirred until hydrogen evolution ceased, at which time it was heated to 85° C., and 98.8 g of chloropropyltrimethoxysilane were added dropwise to the reaction mixture. A white precipitate formed as the addition progressed. Following completion of the addition the reaction mixture was heated at 95° C. for 16 hours, at which time the reaction mixture was cooled, filtered and the liquid phase distilled under reduced pressure to remove the N,N-dimethylformamide. The liquid paraffin was washed from the product using hexane. The identity of the residue as the expected silylhydantoin was confirmed using infra-red and nuclear magnetic resonance spectroscopy.
The silanes and disiloxanes of this invention are particularly useful as coupling agents for bonding glass fibers to organic resins and as self-bonding adhesion promoters for room temperature curable silicone adhesives. Some prior art room temperature curable polysiloxane products employing an acetoxysilane as the curing agent require a primer to achieve adequate adhesion with the substrate to which they are applied. Primers are not required using the hydantoinyl silanes of this invention. | This invention relates to a novel class of organosilanes. The characteristic feature of these silanes is the presence of a hydantoin residue that is bonded to silicon through an alkylene group. | 2 |
This is a continuation of application Ser. No. 08/108,182, filed on Aug. 17, 1993, now U.S. Pat. No. 5,356,269, derived from International Application PCT/GB90/00899, filed on Jun. 11, 1990.
BACKGROUND OF THE INVENTION
This invention is concerned with variable displacement pumps which are used to power and control hydraulic systems.
In a simple hydraulic system, a pump draws oil from a low-pressure reservoir and supplies it at high pressure to a consumer unit (s) such as a ram. The only losses in this system are due to leakage etc., in the pump and ram, and viscous loss in the pipes, but the ram speed is directly related to the pump speed.
As the fluid volumes demanded by the consumer unit(s) will usually be variable, a common way of controlling such a system is to use a controllable bypass, which returns a proportion of the pump output to the reservoir without going through the ram. The speed of the latter can clearly be varied from zero, with the bypass fully open, to the maximum speed, with the bypass completely closed. However, this is very wasteful of energy. In a second form of control, a series valve is located in the high pressure supply, but this is just as inefficient. The valve raises pump pressure above that actually required, thereby wasting energy. At higher pressures, leakages within the pump become more significant, so they act as a bypass, to control the speed.
While the speed of the simple system could be controlled by varying the speed of the pump drive, this is usually impractical, since the drive is either a constant speed electric motor or an engine with a limited speed range. Even if the speed could be varied, the control available could be very slow.
Conventionally, this problem is solved by the different forms of variable displacement pumps. Usually, these are piston pumps, in which the piston stroke is selectively variable by a swash-plate or eccentric, so that the amount of oil delivered per stroke is varied. The pump output can therefore vary independent of the speed of the prime mover. Unlike the systems previously referred to there are no losses caused by bypass or throttle valves.
Conventional variable displacement pumps are reliable and efficient. However, all of them need very high forces to move the swash plate or the eccentric, and an auxiliary power system, usually hydraulic, must be provided for this purpose. This increases the complexity and cost of the pump. Furthermore, because it is obviously undesirable to use a great deal of power to control the pump itself, the response is usually relatively slow. Control by electrical signals requires a further stage, such as electro-magnetic valves. These shortcomings have severely restricted the range of use of variable displacement pumps.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a variable discharge pump comprising a piston reciprocable within a cylinder, a displaceable inlet valve adapted to control admission of lower pressure hydraulic fluid to the swept volume area of the piston and cylinder, a displaceable outlet valve adapted to control delivery of higher pressure fluid from the swept volume area, characterised in that an ER fluid device controls the position of the inlet valve so as to control the volume of fluid delivered by the pump in accordance with demand, the ER fluid device being used either in a passive mode as a brake, to restrain movement of the inlet valve, which movement results from forces generated by the normal working of the pump, or being used in an active mode, as a powered displacement device, to control the movement of the inlet valve directly.
Thus by maintaining the inlet valve open during the whole of the output or delivery stroke of the piston, the delivery is zero; conversely by maintaining the inlet valve closed during the whole of the output or delivery stroke of the piston, the delivery is maximum; while maintaining the inlet valve open during a portion only of the delivery stroke, delivery of only a portion of the swept volume occurs.
Preferably, the pump has a plurality of cylinders e.g., five, each with an inlet and an outlet valve. All the latter are preferably of the poppet type, spring loaded into closed positions, and displaceable by a decrease/increase in pressure to an open position.
BRIEF DESCRIPTION OF THE DRAWING
The invention will now be further described, and will be better understood, by reference to the accompanying drawings, in which:
FIG. 1 shows the cylinder head of a conventional, fixed displacement piston pump;
FIG. 2A shows the piston position;
FIGS. 2B, 2C and 2D show respectively, hydraulic fluid pressures at the inlet and outlet ports for the piston position of FIG. 2A; and
FIGS. 3-6 show respectively four examples of employing ER fluid devices to achieve inlet valve control.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1 is illustrated a cylinder head 1 of one cylinder 2 of a multi-cylinder pump 3, within which a cylinder 2 is a reciprocable piston 4, an inlet valve 5 with a fluid inlet port 6 and an outlet valve 7 with a fluid outlet port 8.
As the piston 4 is withdrawn, pressure of fluid 9 in swept volume chamber 10 falls, and the inlet valve 5 opens, being displaced, against the action of its coil spring 11, to the position shown in chain-dotted line. When the piston 4 starts to return, the inlet valve 5 closes, and the hydraulic fluid in the chamber 10 is compressed. When its pressure exceeds that in the outlet port 8, the outlet valve 7 is forced open against the action of its coil spring 12, and hydraulic fluid is expelled from the chamber 10 into, and beyond, the outlet port 8. As the piston 4 approaches the limit of its travel, the outlet valve 7 closes again under the influence of its spring 17, and the cycle is repeated. As the piston 4 moves to and fro, hydraulic fluid flows alternately through the inlet: and the outlet ports 6, 8. This is shown in FIG. 2B. The output flow is then the maximum possible for a particular pump and speed.
In accordance with the invention however, the position of the inlet valve 5 is positively controlled, rather than being, conventionally either open or closed in accordance with fluid pressure(s) acting on the inlet valve 5 and/or its coil spring 11. Various means of achieving positional control of the inlet valve 5 are described later with reference to FIGS. 3-6, but in principle, if zero delivery is required (to match zero demand) the inlet valve 5 is held open all the time, the reciprocation of the piston 4 merely generating a tidal flow of hydraulic fluid in the lower pressure, inlet port 6. Apart from the return spring 11, the force tending to close the inlet valve 5 would be small, since the pressure drop across it would be small. The only energy losses would be due to viscosity. The fluid pressure within the chamber 10 would remain low, insufficient to open the outlet valve 7, so the output flow into, and beyond, the outlet port 8 would be zero.
If part of the maximum delivery were then required, the inlet valve 5 would be held open during a selected initial part of the output stroke of the piston 4, the valve closing when released. Part of the hydraulic fluid initially contained in the chamber 10 would be expelled through the inlet port 6 as discussed above, but once the inlet valve 5 had closed, however, the remainder of the hydraulic fluid within the chamber 10 would be driven through the output port 8, as normal. The net output flow would therefore be intermediate between the maximum and zero, the exact amount depending upon the proportion of the output stroke remaining when the inlet valve 5 was released. FIGS. 2C and 2D show the flows observed at the inlet port 6 (I/P) and outlet port 8 (O/P) for `High` and `Low` output flows respectively. It must be stressed that since the `excess` output is rejected into the low pressure port 6 etc., the energy losses will be low.
Thus by applying relatively small forces to the inlet valve 5 and thus controlling its position in accordance with the invention, and varying the phase relationship between these forces and the positon of the piston, the output of the pump can be varied from zero to the maximum swept volume.
The inlet valve 5 is controlled by the use of Electro-Rheological (ER) fluids. In essence, ER fluids. In essence, ER fluids are concentrated suspensions of suitable solids, finely divided, in an oily base liquid. Normally these behave similarly to ordinary oils, but when they are exposed to an electric field, their flow behavior changes to that of a Bingham plastic: the yield stress is dependent on the electric field strength. When the field is removed, the ER fluid reverts to its original liquid state. ER fluids are particularly Suitable for this application because:
(a) ER devices are simple and require virtually no precision machining so they can be cheap to make.
(b) Although high voltages are required, current densities are modest, so the control signals can be provided directly by solid-state electronics.
(c) The response of ER fluids is very fast indeed.
In the example shown in FIG. 3 virtually the entire "conventional" pump is unchanged, but a small ER buffer 13 is added to the inlet valve. This buffer 13 consists of two main parts, namely a piston 14 attached to valve stem 15 of the inlet valve 5, and a sleeve 16 held concentric with cylindrical housing 17 of the inlet valve 5 and the piston 14 by insulating end-plates 18 equipped with seals 19. Annular clearance 20 between the piston and the sleeve and 21 between the sleeve and the housing are each approximately 1 mm. The whole of the buffer 13 is filled with ER fluid 22. An external relief tube 23 is provided to equalise the pressures at each end of the valve stem 15.
When the valve stem 15 moves to and fro, ER fluid is driven from one end of the buffer 13 to the other, passing through the annular gaps 20 and 21 respectively between the piston 14 and the sleeve 16 and between the sleeve 16 and the housing 17. The piston 14 is connected to the housing 17 through the return spring 11 and both are at earth potential. Therefore, when a high voltage is applied to the sleeve 16 via the high tension lead H.T. the ER fluid 22 in the annular flow paths 20, 21 is solidified; this prevents further flow, and further movement of the valve stem 15, until the field is removed.
This arrangement generates large forces to resist movement in relation to the electrical control power required. With no field applied it will act as an ordinary viscous damper; this may or may not be an advantage, depending on circumstances.
The basic construction exemplified in FIG. 4 is similar to that shown in FIG. 3, but the ER buffer 13A is composed of tubular plates 24, attached to the valve stem 15 and hence movable, interleaved with fixed position, tubular plates 25 attached to the lower end plate 18, by being inset into that end plate. The plates 24 are kept at earth potential through the return spring 11; while the fixed plates 25 have a high voltage connection H.T. A high voltage applied to the fixed plates 25 solidifies the ER fluid 22 between these and the movable earthed plates 24, so the whole assembly acts in the same way as a linear friction brake until the voltage is removed.
This arrangement will require a larger electrical input than that shown in FIG. 3 to generate a given retarding force. On the other hand, it will also have less damping when no electric field is applied. It will be apparent that as the inlet valve 5 closes, the two sets of plates 24, 25, overlap to a greater extent, and the braking effect will become more pronounced. This could be used to advantage in some situations.
In the example shown in FIG. 5, ER fluid 22 is used in a rather different-way to that of FIGS. 3 and 4, in that the force tending to move the valve stem 15 is applied at right angles to the electric field, so the ER fluids are operating in shear. However, ER fluid will also resist forces applied parallel to the electronic field. The main limitation is that the travel available is limited by the maximum gap between the electrodes, which in turn is limited by the maximum working voltage. The behaviour of ER fluids used `in compression` differs from that of the same fluids used `in shear` in several respects, but in general much greater forces can be generated by a given electrical input by operating in compression rather than in shear.
The travel required in this particular application is limited, so it is feasible to use ER Fluids in compression. This approach allows smaller electrodes to be used; the small travel and simple construction introduces further simplifications in that the entire ER system may be reduced to a sealed flexible rubber capsule 26 with a top metal plate 27 and a bottom multi-plate 28. When a voltage is applied via the H.T. lead to the plate 28, the capsule 26 resists compression; without a voltage, the two plates 27, 28 can easily be pressed together. Since the ER fluid 22 is totally enclosed within the capsule 26, sliding seals are unnecessary, and the relief tube of FIGS. 3 and 4 can be dispensed with. In FIG. 5, the travel available from a single capsule 26 is shown exaggerated; in practice, the travel would be reduced. Alternatively, two or more capsules 26 could be used in series.
While embodiments of FIGS. 3 to 5 show ER Fluid being used to brake the inlet valve 5, resisting the normal flow forces generated within the pump 3, the invention is not limited to this and FIG. 6 shows a system where ER fluid is used actively to move the inlet valve 5.
In FIG. 6, an auxiliary rod 29 is attached to the piston 4 and passes through a seal 30 to operate a secondary piston 31 in a secondary cylinder 32 filled with ER fluid 22; to keep the volume constant, the auxiliary rod 29 emerges through a second seal 33. As the piston 4 descends, ER fluid 22 passes through a port 34 and through the annular gap 35 between a metal cylinder 36 and the inlet valve housing 17. The cylinder 36 is fixed to a tube 37 which forms part of the stem 15 of the inlet valve 5, and moves in insulating, sealed guides 38 and 39. Since the housing 17 is at earth potential a voltage applied from the HT lead to the tube 37 through the spring 11 will solidify the ER fluid 22 in this annular gap 35 and therefore increase the pressure above the cylinder 36. This results in closure of the inlet valve 5. Having passed over the cylinder 36, the ER fluid 22 enters the tube 37 through radial ports 40, and passes upwards until it emerges through a second set of radial ports 41. It then passes through a second annular gap 42 between a plastics cylinder 43 and the housing 17 before re-entering the secondary cylinder 32 through port 44. A sealed guide 45 separates the ER fluid 22 from the fluid 9, e.g. oil, in pump 3.
The plastics cylinder 43 balances the no-field pressure drop in the `working` gap between the cylinder 36 and the housing 17. Since the flow of ER fluid 22 will reverse as the piston 4 changes direction, as long as the voltage is maintained on the HT lead, the inlet valve 5 will close as the piston 4 descends and opens as it retreats upwards. However, if the voltage is removed, the inlet valve 5 will stay open all the time.
This basic system can be modified in various ways. By making the second cylinder 43 out of metal, and providing a second HT connection, the inlet valve 5 can be driven in either direction. Although it is clearly convenient in some circumstances to generate the flow of ER fluid from the movement of the piston 4, in others it might be more efficient to have a separate pump. Similarly, poppet valves are widely used for high pressure applications because they seal extremely well. However, they are liable to be unacceptably noisy for some applications, even though the use of ER fluids will allow the closure to be programmed, by reducing the voltage slowly rather than sharply. In such applications, it might be desirable to replace the poppet valves with another type which do not rely on flow forces, which inevitably increase as the valve closes, in their operation. An `active` ER valve control system, such as that illustrated, would allow such valves to be used.
Thus, the invention basically provides variable displacement performance from a simple, fixed displacement piston pump by providing the possibility of selectively delaying the closure of the inlet valve to `spill` a predetermined proportion of the total swept volume of the pump back into the low-pressure reservoir, with a view to equating so far as is possible pump output with consumer demand, and thereby providing an energy efficient pump.
Furthermore, ER fluids are preferably used to put the invention into effect.
This can be done either:
(a) By using ER fluid passively, as a brake, to restrain movement of the inlet valve, which movement results from forces generated by the normal working of the pump. This brake can use the ER fluid in a `valve`, `clutch` or `compression` geometry. This approach is simple, but limits the range of valves that can be used in the pump.
(b) By using ER fluid actively, as a powered displacement device, to control the movement of the inlet valve directly. The power for this device or actuator may or may not be derived directly from the pump. This approach allows a much wider range of valves to be used in the pump. | A variable discharge pump (3) comprises a piston (4) reciprocable within a cylinder (2), a displaceable inlet valve (5) adapted to control admission of lower pressure hydraulic fluid (9) to the swept volume areal (10) of the piston (4) and cylinder (2), a displaceable outlet valve (7) adapted to control delivery of higher pressure fluid (9) from the swept volume area (10), and means (13, 13A, 26-28, 29-44) to control the position of the inlet valve (5) so as to control the volume of fluid (9) delivered by the pump (3) in accordance with demand. | 8 |
FIELD OF THE INVENTION
[0001] The present invention relates to methods of treating and/or preventing mucositis resulting from radio- and/or chemotherapy, as well as a glucan for use in a therapeutic composition for treatment and/or prevention of mucositis, as well as uses thereof.
BACKGROUND OF THE INVENTION
[0002] Mucositis is defined as inflammation and ulceration of the mucous membranes, and is a common dose-limiting toxic reaction to chemotherapy and radiotherapy. The definition of mucositis is often restricted to the oropharynx and lips, because of the easy access of these areas for evaluation. However, chemotherapy affects all mucous membranes along the gastrointestinal tract as mitotically active cells are sensitive to this treatment. Complications of mucositis may include fibrosis of salivary glands, muscles and blood vessels, loss of the sense of taste and, in extreme cases, osteoradionecrosis (ORN) of underlying bone.
[0003] In RTOG (Radiation Treatment Oncology Group) studies it has been demonstrated a 25% incidence, approximately, of grade 3 and 4 mucositis after radiation therapy delivered in standard conventional dose fractions. Other study groups have reported grade 3 mucositis rates approaching 50%. Moderately accentuated regimens, such as concomitant boost or hyperfractionation, seem to double the incidence of high-grade mucositis, up to 50% to 60%. More aggressive treatment schedules have produced even higher incidences of mucositis; grade 3 from 66% to 86%, and grade 4 from 7% to 48% (Trotti 2000). The prevalence of chemotherapy-induced oral mucositis has generally been reported as ranging from 30% to 39%. A prevalence of 75% has been reported with 5-fluorouracil (Dodd et al. 1996).
[0004] As immune compromised mucous membranes represent a potential opening for local and systemic infections and subsequent complications, mucositis is a serious adverse reaction that might lead to reductions or delays in chemotherapy or radiation treatment, consequently having an adverse impact on the curative potential of the primary care. Furthermore, mucositis is very painful and may prevent the patient from eating. The quality of life is consequently significantly reduced in the affected patients.
[0005] Oral mucositis (stomatitis) with ulcers can manifest itself already a few days after onset of chemotherapy and/or radiotherapy, and is precipitated by a direct toxic effect on the mucosal membranes. The direct toxic effect is caused by nonspecific killing of rapidly dividing basal epithelial cells resulting in epithelial thinning, inflammation, decreased cell renewal, and ultimately ulceration.
[0006] Postoperative radiotherapy is usually indicated in patients after resection of advanced carcinomas of the head and neck. Recently two randomized phase III studies performed by the European Organization for Research and Treatment of Cancer (EORTC) and an intergroup effort of Radiation Therapy Oncology Group (RTOG), Eastern Cooperative Oncology Group (ECOG) and Southwest Oncology Group (SWOG) demonstrated that adjunct cisplatin-based chemotherapy significantly improves the local and regional tumor control compared to radiotherapy alone. The disease-free survival was also significantly longer in both studies. However, this improvement in efficacy was accompanied by a higher incidence of acute adverse events of grade 3 or greater, especially oral mucositis, in the group receiving combined treatment. Despite of increased toxicity, the authors conclude that the addition of concurrent chemotherapy to radiotherapy will be the new standard of care for physically fit patients with head and neck cancer (Bernier et al. 2004; Cooper et al. 2004).
[0007] Aside from the direct effect of radiation or chemotherapy on mucosal cells, mucositis might also be caused by therapy induced neutropenia. Drugs that commonly give dose-limiting oral mucositis are: methotrexate, dactinomycin, and doxorubicin, but also bleomycin, cytarabin, fluorouracil, and mitramycin induce this side effect. The side effect is dose- and schedule related. The combination of cisplatin and continuous infusion of fluorouracil for squamous cell head and neck carcinoma almost always results in severe mucositis (Sonis et al. 1990).
[0008] Patients undergoing chemotherapy often suffer from myelosuppression due to their treatment, and this might induce indirect mucositis. Severe granulocytopenia is conductive to oral infections by Gram-negative bacilli, Gram-positive cocci, fungi such as Candida species, and viruses (particularly Herpes simplex). These infections usually occur at the site of direct mucositis or other oral trauma 12-14 days after drug administration (Sonis et al. 1990; Verdi 1993).
[0009] Atrophic changes are usually seen after a dose of about 2000 cGy administered at a rate of 200 cGy a day. Radiation following chemotherapy may lead to especially severe complications. The degree of damage is directly related to the dose of radiation, but also to factors as age, concurrent diseases (e.g. AIDS), oral hygiene, and tobacco and alcohol usage. Previous treatment may also affect the outcome. The general nutritional and health status of the patient also plays an important role in determining the severity of the complications and both of these can be adversely affected by the complications themselves creating a vicious circle (Reynolds et al. 1980; Shannon et al. 1977; Baker 1982). If the complications are sufficiently severe they will lead to an interruption of treatment and thus, possibly, a complete or partial failure of therapy.
[0010] The previous notion that radiation injury of the oral mucosa is a purely epithelial phenomenon has been supplanted by the recognition that it, similar to radiation injury in other organ systems, is a dynamic process of complex interactions among many cellular compartments, resulting in a number of concurrent and sequential pathophysiological alterations that collectively constitute what is called radiation-induced stomatitis or oral mucositis.
[0011] Oral mucositis is heralded by an initial phase that is characterized by injury to tissues of the submucosa. During this phase, changes are mediated by reactive oxygen species (ROS) through the ceramide pathway, and by activation of a number of transcription factors including nuclear factor-kappa beta (NF-κB). This results in the activation of early response genes, as well as direct oxidative alterations of protein functions, such as, proteins responsible for vascular thromboresistance. Changes occur in endothelial cells, mesenchymal cells, resident inflammatory cells, and extracellular matrix. The initial injury precipitates the upregulation of a second set of genes resulting in direct and indirect signaling and early apoptosis of clonogenic stem cells in the basal epithelium. The signaling molecules are likely to be the proinflammatory cytokines (tumor necrosis factor-α, interleukin 1, and interleukin 6). These signaling molecules also have the ability to further amplify the upregulation of transcription factors (e.g., NF-κB), leading to production of additional proinflammatory cytokines, tissue injury, and apoptosis.
[0012] Deficient renewal of mucosal epithelium occurs despite focal bursts of hyperproliferative activity in response to upregulation of genes associated with epithelium healing. When epithelial apoptosis and necrosis exceeds hyperproliferative activity, an ulcerative phase with full thickness mucosal damage is the visible result. The ulcerative phase is exacerbated by local bacterial colonization, which results in a barrage of cell wall products that penetrates into the submucosa and amplifies the damage.
[0013] Eventually, healing occurs as healthy epithelium migrates from the wound margins, stimulated by signals from the submucosa, and cytokines and other mediators drive additional local response, including angiogenesis.
[0000] Management of Mucositis
[0014] Mucositis and ulceration in the oral cavity can be extremely painful and are a major site of potentially lethal infections. Although many phase I and II studies have been performed with products having shown promising results in animal models (see Velez et al. 2004. Quintessence Int. vol 35:129-136, Management or oral mucositis induced by chemotherapy and radiotherapy: an update), very few, if any, treatments have been demonstrated to be effective in preventing or treating oral mucositis.
[0015] Several agents have been investigated in order to find optimal management principles for mucositis and even though some agents have shown prophylactic effect (Meisenberg et al., 1996), no agent has been shown to be efficient in all settings. Treatment of mucositis is today primarily supportive; strong analgesics in addition to oral hygiene. No standard therapy has been accepted.
[0016] Several authors have reviewed the literature on treatment and prevention strategies for chemotherapy- and radiotherapy-induced oral mucositis, and conclude that further trials are needed (Clarkson et al. 2000; Worthington and Clarkson 2002; Sonis et al. 2004).
[0017] Both topical and systemic prophylactic agents as well as non-pharmacologic prophylaxis are among the treatment regimens that have been tried in oral mucositis. Some cancer treatment regimens make use of specific antidotes (e.g. leucovorin) after moderate-dose or high-dose methotrexate (Allegra and Boarman 1990) to reduce the toxic effect of the cancer drug. Due to the mechanism of action of antiseptics and antifungals, prophylactic chlorhexidine (Ferretti et al. 1990; McGaw and Belch 1985) and nystatin or clotrimazole (Preston and Briceland 1995) reduce the risk of indirect mucotoxicity from bacteria and fungi. Sucralfate is a basic aluminum salt of sulfated sucrose which forms an ionic bond to proteins in ulcerations. This produces a protective barrier that promotes healing. Sucralfate has shown a modest benefit in patients receiving a cisplatin/fluorouracil regimen for various solid tumors (Pfeiffer et al. 1990). Oral cryotherapy/ice chips have been shown to have effect in patients receiving bolus doses of 5-fluorouracil (Rocke et al. 1993), but unsuitable for patients receiving continuous infusion of 5-fluorouracil.
[0018] Interventions that have failed to show effect in oral mucositis, include the application of prostaglandin E2 (Labar et al. 1993), to some extent allopurinol (xanthine oxidase inhibitor) (Loprinzi et al. 1995), pentoxifylline (PTX) (Stockschlader et al. 1993; Attal et al. 1993; van der Jagt et al. 1994) and filgrastim, a granulocyte colony-stimulating factor (Gabrilove et al. 1988; Pettengell et al. 1992).
[0000] β-glucans in Radioprotection
[0019] “β-glucan” is the common name for homopolysaccharides consisting of β-D-glucopyranosyl units. The backbone units are linked by β-1,3- or β-1,4-linkages, or combinations of these two. β-glucans from different sources and isolated through different methods may have a variety of additional structural features like single glucosyl units attached to the backbone, β-1,6-linked side chains or β-1,3-linked side chains at different ratios.
[0020] It has been known for many years that injection of β-glucan to animals receiving radiation can induce enhanced hematopoietic recovery (Patchen et al. 1984) and increased survival rate (Patchen and MacVittie 1986; Hofer et al. 1995) from cobalt-60 radiation. The increase in survival rate is hypothesized to be due to the prevention of radiation induced myelosuppression and stimulation of the bone marrow (Patchen et al. 1990; Hofer and Pospisil 1997), a theory that has been supported by recent findings that yeast β-glucan is able to induce increased bone marrow mononuclear cell colony formation (Turnbull et al. 1999). All the above studies refer to parenteral administration of β-glucans. No studies have earlier been carried out to examine the effect of orally administered β-glucan on radio- or chemotherapy induced side-effects such as mucositis.
[0021] In the present invention it was surprisingly found that water-soluble β-1,3-glucan is effective in preventing or treating oral mucositis and ulceration in cancer patients undergoing radiation treatments to head and neck. Accordingly, novel methods of prevention and treatment, novel use of β-glucans, as well as novel use of β-glucans for manufacturing a medicament for preventing or treating mucositis are devised herein.
SUMMARY OF THE INVENTION
[0022] The current invention describes a method for preventing and/or treating mucositis with a branched water soluble β-1,3-glucan. Water soluble β-glucan is used to prevent development of and/or promote healing of ulcers as exemplified by mouth and oropharynx ulcerations resulting from radio- and/or chemotherapy. The soluble β-glucan can be applied directly to the potential affected mucosal areas as a solution, or mixture, or rinse, or gel, or mixed into any pharmaceutically acceptable carrier or vehicle. Other aspects of the invention are glucans for use in therapeutic compositions and uses of β-glucan.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention relates to prevention or treatment of mucositis. More particularly, it relates to a method of preventing or treating oral mucositis. In a preferred embodiment, the oral mucositis is radiation and/or chemotherapy induced oral mucositis. The method of the invention comprises applying a preparation comprising water-soluble immunomodulatory β-glucan to the susceptible or affected mucosal surface. The preparation may be a rinse, mixture, gel, ointment, cream, or another suitable formulation. Furthermore, water-soluble β-glucan may be the only active component in the preparation or the β-glucan may be combined with one or several other active components like e.g. antiseptics and/or antifungals, e.g. chlorhexidine, nystatin, clotrimazole; sucralfate; analgesics; etc.
[0024] The water-soluble immunomodulatory β-glucan used in the invention may be isolated from several organisms. Glucans with known immunomodulatory activities are e.g. lentinan isolated from Lentinus edodes having a β-1,6-linked single glucosyl unit for approximately every 3 main chain unit (Sasaki and Takasuka 1976). Similar glucans having β-1,3-linked main chain with single β-1-6-linked glucosyl units attached thereto are scleroglucan isolated from Sclerotium sp. (Singh et al. 1974; Farina et al. 2001) and shizophyllan isolated from Schizophyllum commune (Akima et al. 1985). A soluble β-1,3-glucan can also be obtained from seaweed (Nelson and Lewis 1974), and a water soluble β-1,3/1,4-glucan can be isolated from cereals (Estrada et al. 1997), or derived from lichens (Demleitner et al. 1992). Bacterial β-1,3-glucan, curdlan, from Alcaligenes faecalis can be made water soluble and immunomodulatory (Seljelid et al. 1984). Preferably, the β-glucan originates from yeast, fungi, cereals, algae, or bacteria. More preferably, said glucan originates from yeast. Even more preferably, said glucan originates from the yeast family Saccharomyces. In a particularly preferred embodiment, the β-glucan originates from Saccharomyces cerevisiae. The water-soluble immunomodulatory β-glucan may be of any structure, however, it is preferably a water-soluble non-derivatized β-1,3-glucan, with side-chains anchored to the backbone through a β-1,6-linkage. Preferably, the backbone consists of β-1,3-linked D-glucopyranosyl units, while the side chains may comprise β-1,3-linked and/or β-1,6-linked D-glucopyranosyl units. The former type of side-chains are termed β-1,3 side-chains, while the latter are termed β-1,6 side-chains. Preferably, said β-1,6 side-chains consist of 0 to 4 units. More preferably, said side-chains consist exclusively of β-1,3-linked D-glucopyranosyl units. The above features are important both for the current β-glucan's water solubility and immunomodulatory activity (Engstad 1994). As teached above, the glucan may contain certain amounts of β-1,6-linked glucosyl chains, but these are to a certain extent negative with respect to the β-glucans immunomodulatory abilities (see Engstad 1994), the content of which are incorporated herein by reference. These undesired β-1,6 side-chains are found in other non-derivatized soluble yeast β-glucans described in the literature (Onderdonk et al. 1992) or patents (Jamas et al. 1994; Kelly 2001). Accordingly, an especially preferred glucan is a branched β-1,3-glucan with β-1,3 side chains anchored through a β-1,6-linkage.
[0025] The β-glucan concentration of the preparation may be in the range from 0.1% to 25% by weight, preferably 0.1% to 10% by weight, more preferably 0.5% to 2.5% by weight. The preparation may be administered either as a single daily treatment or repeated daily treatments before, and/or under, and/or after e.g. a cancer treatment regime or bone marrow transplantation. The preparation may be administered orally to contact the mucosal surfaces of the oral cavity, the pharynx and the intestinal tract to prevent and/or heal the formation of mucositis, e.g. in radio- or chemotherapy treated cancer patients. Anal administration of the preparation is also possible. The method of the present invention may be applied to any animal, preferably a mammal, and more preferably a human being.
[0026] Another aspect of the current invention is a method for preparing a medicament comprising the β-glucan as described above. The process comprises first isolating intact yeast cell walls or any other source of β-glucan as described above. The intact cell walls, or alternative source, are treated with formic acid and optionally digested with a β-(1,6)-glucanase to form a gel with non-Newtonian viscosity and thixotropic properties. This type of gel is ideal for mucosal application. A general method for isolation and manufacture of the current β-glucan is described in patent EP 0759089 the content of which are incorporated herein by reference.
[0027] A further aspect of the current invention is a glucan for use in a therapeutic composition for treatment or prevention of mucositis, wherein said glucan is a water-soluble immunomodulatory β-1,3-glucan. The β-glucan is as described above. Preferably, the water-soluble immunomodulatory β-1,3-glucan have a branched nature with β-1,3-linked side chains anchored through a β-1,6-linkage. More preferably, said side-chains consist exclusively of β-1,3-linked D-glucopyranosyl units. In a preferred embodiment the mucositis is oral mucositis. The mucositis may be caused by radiotherapy and/or chemotherapy.
[0028] Yet another aspect of the current invention is the use of immunomodulatory β-glucan for manufacturing a medicament for the treatment or prevention of mucositis in an animal in need thereof. The β-glucan is as described above. Preferably, the water-soluble immunomodulatory β-1,3-glucan is branched with β-1,3-linked side chains anchored through a β-1,6-linkage. More preferably, said side-chains consist exclusively of β-1,3-linked D-glucopyranosyl units. In a preferred embodiment the mucositis is oral mucositis. The mucositis may be caused by radiotherapy and/or chemotherapy. The animal may be any animal, preferably a mammal, and most preferably a human being.
[0029] All publications, patents and patent applications mentioned in this specification are indicative of the level of skill of those skilled in the art to which this invention pertains, and are herein incorporated by reference to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference.
[0030] The theory underlying the invention is not part of the claims and the inventor does not wish to be bound by any particular theory explaining the invention. In fact, it is fully anticipated that the theory underlying the present invention will evolve as science develop and mature.
EXAMPLES
[0031] The following examples are meant to illustrate how to make and use the invention. They are not intended to limit the scope of the invention in any manner or to any degree.
Example I
[0032] Herein is described the use of soluble β-glucan (SBG) to prevent and or heal oral mucositis in conjunction to radiotherapy in a 30 year old male with head and neck cancer. SBG is a water soluble branched beta-1,3-linked yeast derived glucan with intact beta-1,3-linked side chains anchored through a beta-1,6-linkage to the main chain. A minority of side chains show repetitive beta-1,6-linkages. The intramolecular ratio of repetitive beta-1,6-linkages versus beta-1,3-linkages is approximately 1:50, or less. The patient was diagnosed with cancer in the tongue in January 2002 and a surgical excision of the tumour was performed, whereafter local brachy therapy in the tongue was given. In November 2002, 10 months after surgery, recurrence of the cancer was diagnosed in a lymph node in the neck, and the patient was readmitted to hospital for surgery in December 2002 and from January 2003 also radiotherapy to the neck region. Radiotherapy (a total of 60 Gy) was given 5 days per week for 6 consecutive weeks. Concomitant to the radiotherapy the patient took approximately 80-100 mg SBG as a 20 mg/ml aqueous solution administered orally as a daily dose until 14 days after ending radiotherapy. The patient did not develop oral mucositis above grade I during or after the radiotherapy.
Example II
[0033] An exploratory, randomized, parallel group study comparing the protective effect of soluble β-glucan or placebo in oral mucositis in head and neck cancer patients receiving radiation therapy is described. 40 patients undergoing radiation for histologically confirmed squamous cell carcinoma of the oral cavity or pharynx (1.8-2.0 Gy/day, 5 days per week; totally 59.4-70 Gy) is included in the study. A cohort also receives chemotherapy. Soluble β-glucan (SBG) as an aqueous solution is given orally throughout the whole radiation period at a daily dosage of 500-1000 mg as a 15 mg/ml aqueous solution to 20 patients, whereas 20 patients are treated with methylcellulose as placebo. SBG is a water soluble branched beta-1,3-linked yeast derived glucan with intact beta-1,3-linked side chains anchored through a beta-1,6-linkage to the main chain. A minority of side chains show repetitive beta-1,6-linkages. The intramolecular ratio of repetitive beta-1,6-linkages versus beta-1,3-linkages is approximately 1:50, or less.
[0034] The β-glucan treatment group shows reduction in number of patient having grade 2 or higher oral mucositis as compared to the placebo group.
[0035] Having now fully described the present invention in some detail by way of illustration and example for purpose of clarity of understanding, it will be obvious to one of ordinary skill in the art that same can be performed by modifying or changing the invention by with a wide and equivalent range of conditions, formulations and other parameters thereof, and that such modifications or changes are intended to be encompassed within the scope of the appended claims.
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CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority to and the benefit of U.S. Provisional Application No. 61/826,444, filed on May 22, 2013 in the U.S. Patent and Trademark Office, the entire content of which is incorporated herein by reference.
BACKGROUND
1. Field
One or more embodiments of the present invention relate to a secondary battery.
2. Description of the Related Art
In general, unlike primary batteries which are not rechargeable, a secondary battery is both dischargeable and rechargeable. A secondary battery is used as an energy source of, for example, a mobile device, an electric vehicle, a hybrid vehicle, an electric bicycle or an uninterruptible power supply (UPS). Based on the type of external device used with the batteries, a single secondary battery may be used or a battery module in which a plurality of batteries are bundled up by electrically connecting the batteries may be used.
SUMMARY
One or more embodiments of the present invention include a secondary battery in which an electric short circuit between different polarities of the secondary battery caused by intruding foreign substances may be prevented.
According to one or more embodiments of the present invention, a secondary battery includes: a cap plate sealing an electrode assembly; a terminal plate disposed on the cap plate and electrically connected to the electrode assembly; an insulation member formed between the cap plate and the terminal plate; and a short circuit preventing portion that is formed on at least one of the terminal plate and the insulation member and prevents an electrical short circuit due to a foreign material intruding between the terminal plate and the cap plate.
For example, the short circuit preventing portion may be formed on the insulation member.
For example, the insulation member may be formed to surround the terminal plate, and the short circuit preventing portion may be formed on an upper surface of the insulation member formed on the outer portion of the terminal plate.
For example, the short circuit preventing portion may include a protrusion upwardly protruding from the upper surface of the insulation member.
For example, the short circuit preventing portion may be formed in the form of a closed loop along a boundary of the insulation member surrounding the terminal plate.
For example, the protrusion of the short circuit preventing portion may protrude up to the same height as the terminal plate.
For example, the short circuit preventing portion may include an inclined upper surface of the insulation member.
For example, the upper surface of the insulation member may be downwardly inclined toward the terminal plate.
For example, the upper surface of the insulation member may be inwardly inclined in order to limit a flow of a foreign material within the terminal plate.
For example, the short circuit preventing portion may be formed in the form of a closed loop along a boundary of the insulation member surrounding the terminal plate.
For example, the short circuit preventing portion may include a stepped side surface of the insulation member.
For example, the side surface of the insulation member may include an upper side portion and a lower side portion, wherein the insulation member may have an overhang structure in which the upper side portion protrudes outwards more than the lower side portion.
For example, the short circuit preventing portion may comprise a first short circuit preventing portion having an inclined upper surface of the insulation member, a second short circuit preventing portion in the form of a protrusion protruding from the upper surface of the insulation member, and a third short circuit preventing portion having a stepped side surface.
For example, the short circuit preventing portion may be formed on the terminal plate. appreciate
For example, the short circuit preventing portion may comprise a groove portion formed in the terminal plate.
For example, the short circuit preventing portion may be formed in a boundary area adjacent to the insulation member.
For example, the short circuit preventing portion may comprise a first short circuit preventing portion having a groove portion formed in the terminal plate and a second short circuit preventing portion formed to surround the terminal plate.
For example, the second short circuit preventing portion may include at least one of an inclined upper surface of the insulation member, a protrusion protruding from the upper surface of the insulation member, and a stepped side surface of the insulation member.
According to the embodiments of the present invention, an electric short circuit between different polarities of a secondary battery caused by intrusion of a foreign substance such as salt water may be prevented. For example, in a salt water spray test in which salt water is sprayed on a secondary battery, the salt water dropping on a terminal plate may flow on a cap plate, and accordingly, a short circuit path might be formed from the terminal plate to the cap plate due to ion conduction but a short circuit preventing portion according to the embodiments of the present invention prevents formation of a short circuit path, thereby preventing a short circuit between different polarities and a malfunction of a secondary battery due to this short circuit.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a secondary battery according to an embodiment of the present invention;
FIG. 2 is an exploded perspective view of the secondary battery illustrated in FIG. 1 ;
FIG. 3 is a cross-sectional view of the secondary battery of FIG. 1 cut along a line III-III;
FIGS. 4A and 4B illustrate a portion of a secondary battery including a short circuit preventing portion according to an embodiment of the present invention;
FIGS. 5A and 5B illustrate a portion of a secondary battery including a short circuit preventing portion according to another embodiment of the present invention;
FIGS. 6A and 6B illustrate a portion of a secondary battery including a short circuit preventing portion according to another embodiment of the present invention;
FIGS. 7A and 7B illustrate a portion of a secondary battery including a short circuit preventing portion according to another embodiment of the present invention;
FIGS. 8A and 8B illustrate a portion of a secondary battery including an insulation member according to another embodiment of the present invention;
FIGS. 9 and 10 illustrate a portion of a secondary battery including an insulation member according to another embodiments of the present invention;
FIGS. 11A and 11B illustrate a portion of a secondary battery including an insulation member according to another embodiment of the present invention.
DETAILED DESCRIPTION
Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout.
FIG. 1 is a perspective view of a secondary battery according to an embodiment of the present invention. FIG. 2 is a disassembled perspective view of the secondary battery illustrated in FIG. 1 .
Referring to FIGS. 1 and 2 , a pair of electrode terminals, that is, first and second electrode terminals 110 and 120 which have opposite polarities may protrude from the secondary battery. For example, the first and second electrode terminals 110 and 120 are electrically connected to an electrode assembly 150 accommodated in the secondary battery, and the first and second electrode terminals 110 and 120 are respectively electrically connected to first and second electrode plates of the electrode assembly 150 to thereby supply discharge power accumulated in the secondary battery to the outside or to function as a positive electrode terminal or a negative electrode terminal in order to receive charging power from the outside. For example, the first and second electrode terminals 110 and 120 may be formed on two portions of the secondary battery.
According to another embodiment of the present invention, a cap plate 100 of the secondary battery may be electrically connected to the electrode assembly 150 to function as a terminal, and in this case, one of the first and second electrode terminals 110 and 120 may be omitted.
FIG. 3 is a cross-sectional view of the secondary battery of FIG. 1 cut along a line III-III according to an embodiment of the present invention. Referring to FIG. 3 , the secondary battery includes the electrode assembly 150 , the first and second electrode terminals 110 and 120 , and collector members 117 and 127 through which the electrode assembly 150 and the first and second electrode terminals 110 and 120 are electrically connected to each other. Also, the secondary battery may include a case 180 accommodating the electrode assembly 150 and the cap plate 100 encapsulating an opening portion of the case 180 , in which the electrode assembly 150 is accommodated. The cap plate 100 is coupled to an upper end of the case 180 , in which the electrode assembly 150 is accommodated, and may encapsulate the opening portion of the case 180 . For example, the cap plate 100 and the case 180 may be coupled to each other via welding along an edge of the cap plate 100 .
In one embodiment, the cap plate 100 may include a vent portion 108 , which fractures to relieve internal pressure if the internal pressure of the case 180 exceeds a previously set point, and an encapsulation unit 109 that encapsulates an electrolyte solution inlet.
The electrode assembly 150 may be accommodated in the case 180 of the secondary battery, and may include first and second electrode plates 151 and 152 having opposite polarities and a separator 153 located between the first and second electrode plates 151 and 152 . The electrode assembly 150 may be a winding type in which the first and second electrode plates 151 and 152 and the separator 153 are wound up in the form of a jelly roll, or a stack type in which the first and second electrode plates 151 and 152 and the separator 153 are alternately stacked. The cap plate 100 may be assembled at an upper opening portion of the case 180 , in which the electrode assembly 150 is accommodated, and for electrical connection between the electrode assembly 150 and an external circuit or between the electrode assembly 150 and another adjacent secondary battery, the first and second electrode terminals 110 and 120 that are electrically connected to the electrode assembly 150 may be formed on an outer portion of the cap plate 100 .
The first and second terminals 110 and 120 may have different polarities and may be electrically connected to the first electrode plate 151 and the second electrode plate 152 of the electrode assembly 150 , respectively.
The first electrode terminal 110 may include a first collector terminal 115 and a first terminal plate 111 coupled to the first collector terminal 115 . Similarly, the second electrode terminal 120 may include a second collector terminal 125 and a second terminal plate 121 coupled to the second collector terminal 125 . Hereinafter, the collector terminals 115 and 125 may refer both to the first and second collector terminals 115 and 125 or selectively either the first collector terminal 115 or the second collector terminal 125 . Also, the terminal plates 111 and 121 may refer both to the first and second terminal plates 111 and 121 or selectively either the first terminal plate 111 or the second terminal plate 121 . As will be described later, the first and second collector terminals 115 and 125 are respectively coupled to first and second collector members 117 and 127 ; the collector members 117 and 127 may refer to both the first and second collector members 117 and 127 or selectively either the first collector member 117 or the second collector member 127 .
The first and second collector terminals 115 and 125 may pass through the cap plate 100 to be withdrawn out of the cap plate 100 . Accordingly, a terminal hole 100 ′ may be formed in the cap plate 100 , into which the collector terminals 115 and 125 are inserted to be assembled. In detail, the first and second collector terminals 115 and 125 are inserted upwardly, in a direction from a lower portion to an upper portion of the cap plate 100 , and may be inserted to pass through the terminal hole 100 ′ of the cap plate 100 .
The first and second collector terminals 115 and 125 may include first and second collector terminal fixing portions 115 a and 125 a respectively formed in upper and lower portions of the collector terminals 115 and 125 along a length direction, and may include first and second collector terminal flange portions 115 b and 125 b . For example, the first and second collector terminals 115 and 125 may be assembled to pass through the cap plate 100 , and may include the first and second collector terminal fixing portions 115 a and 125 a exposed above the cap plate 100 and first and second collector terminal flange portions 115 b and 125 b located below the cap plate 100 .
The first and second collector terminal fixing portions 115 a and 125 a are included to fix positions of the first and second collector terminals 115 and 125 , and may be fixed to upper surfaces of the first and second terminal plates 111 and 121 by using a riveting method. For example, the first and second collector terminal fixing portions 115 a and 125 a are in a flange form that extend laterally from a main body of the first and second collector terminals 115 and 125 , and may be fixed to the upper surfaces of the first and second terminal plates 111 and 121 . A groove that is concavely indented according to pressurization of a processing tool which rotates at a high speed may be formed in an upper end portion of the collector terminal fixing portions 115 a and 125 a , and as the upper end portion of the collector terminal fixing portions 115 a and 125 a are pulled to the side according to pressurization of the processing tool, the first and second collector terminal fixing portions 115 a and 125 a may be closely adhered to the upper surfaces of the terminal plates 111 and 121 .
The first and second collector terminal flange portions 115 b and 125 b may have a flange shape that is extended over an outer diameter of the terminal hole 100 ′ so that the collector terminals 115 and 125 do not disengage from the terminal hole 100 ′ of the cap plate 100 . In one embodiment, the collector terminals 115 and 125 are assembled to be inserted into the terminal hole 100 ′ from the lower portion of the cap plate 100 , and positions of the collector terminals 115 and 125 may be fixed by riveting the collector terminal fixing portions 115 a and 125 a exposed above the cap plate 100 while they are supported under the cap plate 100 via the collector terminal flange portions 115 b and 125 b.
The collector terminals 115 and 125 may be inserted into the terminal hole 100 ′ of the cap plate 100 while being electrically insulated from the cap plate 100 . For example, first and second seal gaskets 113 and 123 may be inserted into the terminal hole 100 ′, and as the collector terminal 115 and 125 are inserted with the seal gaskets 113 and 123 located between the seal gaskets 113 and 123 , the collector terminals 115 and 125 may be insulated from the cap plate 100 . The seal gaskets 113 and 123 seal a portion around the terminal hole 100 ′ to prevent leakage of an electrolyte solution contained in the case 180 and seal the case to prevent intrusion of external impurities.
First and second lower insulation members 114 and 124 may be located between the collector terminals 115 and 125 and the cap plate 100 ; the lower insulation members 114 and 124 may insulate the collector terminals 115 and 125 from the cap plate 100 . Thus, by locating the seal gaskets 113 and 123 around the terminal hole 100 ′ through which the collector terminals 115 and 125 pass, and locating the lower insulation members 114 and 124 between the collector terminals 115 and 125 and the cap plate 100 , the collector terminals 115 and 125 and the cap plate 100 may be insulated from each other.
In one embodiment, the lower insulation members 114 and 124 may seal the portion around the terminal hole 100 ′, together with the seal gaskets 113 and 123 , thereby preventing leakage of an electrolyte solution and intrusion of external impurities. The lower insulation members 114 and 124 may also be extended between the collector members 117 and 127 and the cap plate 100 .
The collector terminals 115 and 125 may be electrically connected to the electrode assembly 150 via the collector members 117 and 127 . The collector members 117 and 127 may include first and second collector plates 117 b and 127 b that comprise a lower portion of the collector members 117 and 127 and are coupled to the electrode assembly 150 and lead portions 117 a and 127 a that comprise an upper portion of the collector members 117 and 127 and are coupled to the collector terminals 115 and 125 .
The collector plates 117 b and 127 b may be coupled to two side edges of the electrode assembly 150 , and may be coupled by welding to a non-coated portion formed at an edge of the electrode assembly 150 , that is, a non-coated portion of each of the first and second electrode plates 151 and 152 where no electrode active material is formed. For example, the first collector plate 117 b may be coupled to a non-coated portion of the first electrode plate 151 , and the second collector plate 127 b may be coupled to a non-coated portion of the second electrode plate 152 .
The lead portions 117 a and 127 a may be portions that are extended from and bent with respect to the collector plates 117 b and 127 b so as to face the collector terminals 115 and 125 , and terminals holes 117 ′ and 127 ′ may be formed for coupling of the collector terminals 115 and 125 (see FIG. 2 ). For example, lower end portions of the collector terminals 115 and 125 may be respectively inserted into the terminal holes 117 ′ and 127 ′ of the lead portions 117 a and 127 a , and the collector terminals 115 and 125 and the lead portions 117 a and 127 a may be assembled to face each other. Also, the collector terminals 115 and 125 and the lead portions 117 a and 127 a may be coupled by welding portions around the terminal holes 117 ′ and 127 ′ where they contact each other.
The terminal plates 111 and 121 may be located on the cap plate 100 . The terminal plates 111 and 121 are electrically connected to the collector terminals 115 and 125 , and may provide a relatively broad terminal area extending over the collector terminals 115 and 125 . The terminal plates 111 and 121 may be connected to the collector terminals 115 and 125 (in detail, the collector terminal fixing portions 115 a and 125 a ) via riveting, but the embodiments of the present invention are not limited thereto; for example, the terminal plates 111 and 121 may be connected to collector terminals by using various methods such as welding or screw coupling.
An insulation member 112 may be located between the first terminal plate 111 and the cap plate 100 . The insulation member 112 may insulate the first terminal plate 111 from the cap plate 100 .
According to an embodiment of the present invention, one of the first and second terminal plates 111 and 121 , for example, the second terminal plate 121 , and the cap plate 100 may have the same polarity, and in this case, an insulation member may be omitted between the second terminal plate 121 and the cap plate 100 .
According to another embodiment of the present invention, the second terminal plate 121 and the cap plate 100 may have different polarities. For example, the cap plate 100 may have neither a positive polarity nor a negative polarity but may be insulated from both a positive polarity or a negative polarity and be electrically neutral. In one embodiment, in order to insulate the first and second terminal plates 111 and 121 from the cap plate 100 , a pair of insulation members surrounding the first and second terminal plates 111 and 121 may be provided.
According to an embodiment of the present invention, a short circuit preventing portion S 1 is formed on the insulation member 112 and/or the terminal plate 111 . The short circuit preventing portion S 1 formed on the insulation member 112 and/or the terminal plate 111 may be selectively formed on one of the insulation member 112 and the terminal plate 111 or both the insulation member 112 and the terminal plate 111 .
The short circuit preventing portion S 1 may prevent an electrical short circuit between the terminal plate 111 and the cap plate 100 , which is caused by foreign materials located between the terminal plate 111 and the cap plate 100 . For example, the short circuit preventing portion S 1 blocks formation of a short circuit path from the terminal plate 111 to the cap plate 100 , thereby preventing an electrical short circuit via the short circuit preventing portion S 1 so that no short circuit path is formed due to foreign materials such as salt between the terminal plate 111 and the cap plate 100 having different polarities. For example, in a salt water spray test in which salt water is sprayed on a secondary battery, when salt water dropping on the terminal plate 111 flows onto the cap plate 100 , a short circuit path may be formed from the terminal plate 111 onto the cap plate 100 due to ion conduction, and a malfunction may be caused due to electricity flowing between different polarities of the secondary battery.
The short circuit preventing portion S 1 may be formed on the terminal plate 111 or the insulation member 112 surrounding a boundary of the terminal plate 111 , thereby blocking an electrical short circuit path from the terminal plate 111 to the cap plate 100 due to foreign materials having an electrical conductivity, such as salt water.
For example, when a liquid foreign material flows downward due to gravity, a short circuit path may be formed between the terminal plate 111 and the cap plate 100 , and in order to prevent formation of this short circuit path, a short circuit preventing portion S 1 in the form of a step for blocking a continuous flow of a foreign material, in the form or a protrusion, or in the form of a groove portion for blocking a flow of a foreign material by accommodating the flow may be formed on the terminal plate 111 or on the insulation member 112 surrounding the boundary of the terminal plate 111 . The short circuit preventing portion S 1 will be described in detail below.
FIGS. 4A and 4B illustrate a short circuit preventing portion S 1 according to an embodiment of present invention. FIG. 4B is a cross-sectional view cut along a line IV-b of FIG. 4A .
Referring to FIGS. 4A and 4B , the short circuit preventing portion S 1 is formed on the insulation member 112 surrounding the terminal plate 111 . In detail, the insulation member 112 surrounds a periphery of the terminal plate 111 from the outside and the short circuit preventing portion S 1 in the form of a step may be formed on a side of the insulation member 112 .
For example, a side surface 112 c of the insulation member 112 is a portion of the insulation member 112 that covers a side 111 c of the terminal plate 111 , and may be a portion of the insulation member 112 covering the side 111 c of the terminal plate that connects an upper surface 111 a of the terminal plate 111 exposed to the outside and a lower surface 111 b of the terminal plate 111 that faces the cap plate 100 .
For example, the short circuit preventing portion S 1 may be formed on the external side surface 112 c of the insulation member 112 opposite to the terminal plate 111 . The short circuit preventing portion S 1 may cut off a continuous flow of a foreign material flowing along the external side surface 112 c of the insulation member 112 , thereby preventing a short circuit between the terminal plate 111 and the cap plate 100 .
For example, the short circuit preventing portion S 1 may have a step shape between an upper side portion 112 a and a lower side portion 112 b . For example, the insulation member 112 may have an overhang structure in which the upper side portion 112 a protrudes outwards more than the lower side portion 112 b . In other words, the short circuit preventing portion S 1 in the form of a step may be formed as the upper side portion 112 a protrudes outwards in an opposite direction from the terminal plate 111 more than the side lower portion 112 b . A liquid foreign material flowing along the upper side portion 112 a is not able to flow along the lower side portion 112 b which is inwardly stepped, and thus, the continuous liquid flow may be cut.
For example, the short circuit preventing portion S 1 may have a closed loop form along the entire side surface 112 c of the insulation member 112 . Because the short circuit preventing portion S 1 surrounds the boundary of the terminal plate 111 , the flow of foreign materials flowing from the terminal plate 111 in any direction may be effectively blocked.
FIGS. 5A and 5B illustrate a short circuit preventing portion S 2 according to another embodiment of present invention. FIG. 5B is a cross-sectional view cut along a line V-b of FIG. 5A .
Referring to FIGS. 5A and 5B , the short circuit preventing portion S 2 may be formed on an insulation member 212 formed to surround a terminal plate 111 . In detail, the insulation member 212 surrounds the terminal plate 111 from the outside, and the short circuit preventing portion S 2 may be formed on an upper surface 212 a of the insulation member 212 formed on the outer portion of the terminal plate 111 . For example, the upper surface 212 a of the insulation member 212 may refer to a surface formed on the same side as an upper surface 111 a of the terminal plate 111 exposed to the outside.
The short circuit preventing portion S 2 may be formed on the upper surface 212 a of the insulation member 212 , and may have an inclined surface formed on the insulation member 212 . For example, the upper surface 212 a of the insulation member 212 may be inclined toward an inner portion of the insulation member 212 where the terminal plate 111 is located. That is, the short circuit preventing portion S 2 may be downwardly inclined toward the terminal plate 111 . Accordingly, a flow of a foreign material on the upper surface 212 a of the insulation member 212 flows to the terminal plate 111 but does not flow to the cap plate 100 on an outer portion of the terminal plate 111 . Accordingly, the flow of the foreign material may be limited inside the terminal plate 111 , and the flow of the foreign material flowing to the cap plate 100 on the outer portion of the terminal plate 111 may be blocked. Consequently, an electrical short circuit between the terminal plate 111 and the cap plate 100 may be prevented.
While the short circuit preventing portion S 2 formed of the inclined surface is illustrated as an oblique plane in FIG. 5B , the embodiments of the present invention are not limited thereto; the short circuit preventing portion S 2 may also be a round and curved surface.
The short circuit preventing portion S 2 may be in the form of a rim along a boundary of the insulation member 212 . The short circuit preventing portion S 2 may be in the form of a closed loop along the boundary of the insulation member 212 to surround the terminal plate 111 , thereby blocking a flow of a foreign material flowing from the upper surface 111 a of the terminal plate 111 in any direction.
FIGS. 6A and 6B illustrate a short circuit preventing portion S 3 according to another embodiment of present invention. FIG. 6B is a cross-sectional view cut along a line VI-b of FIG. 6A .
Referring to FIGS. 6A and 6B , the short circuit preventing portion S 3 is formed on an insulation member 312 surrounding a terminal plate 111 . In detail, the insulation member 312 surrounds a periphery of the terminal plate 111 from the outside, and the short circuit preventing portion S 3 in the form of a protrusion may be formed on an upper surface 312 a of the insulation member 312 formed in an outer portion of the terminal plate 111 .
For example, an upper surface of the insulation member 312 may refer to a surface formed on the same side as an upper surface 111 a of the terminal plate 111 exposed to the outside. The short circuit preventing portion S 3 may be formed in the form of a rim along a boundary of the insulation member 312 .
The short circuit preventing portion S 3 may be formed in the form of a closed loop along the boundary of the insulation member 312 to surround the terminal plate 111 , thereby blocking a flow of a foreign material flowing from the upper surface 111 a of the terminal plate 111 in any direction.
Because the short circuit preventing portion S 3 is formed in the form of a protrusion upwardly protruding from the upper surface 312 a of the insulation member 312 , a flow of a foreign material flowing from the terminal plate 111 may be blocked, and an electrical short circuit caused due to the flow of the foreign material may be prevented. For example, the short circuit preventing portion S 3 may function as a dam that blocks a flow of a foreign material, or even when a foreign material overflows the short circuit preventing portion S 3 , the short circuit preventing portion S 3 in the form of a protrusion cuts the continuous flow of the foreign material, thereby preventing an electrical short circuit caused due to the continuous flow of the foreign material such as salt water.
For example, a protrusion height H 2 of the short circuit preventing portion S 3 may be the same as a height H 1 of the terminal plate 111 or higher. The short circuit preventing portion S 3 which is formed at a height equal to or higher than the terminal plate 111 may prevent a liquid foreign material such as salt water from flowing down from the terminal plate 111 .
FIGS. 7A and 7B illustrate a short circuit preventing portion S 4 according to another embodiment of present invention. FIG. 7B is a cross-sectional view of the secondary battery cut along a line VII-b of FIG. 7A .
Referring to FIGS. 7A and 7B , the short circuit preventing portion S 4 is formed on a terminal plate 211 . For example, the short circuit preventing portion S 4 may be formed in a boundary area of the terminal plate 211 adjacent to an insulation member 412 .
The short circuit preventing portion S 4 may include a groove portion formed in the terminal plate 211 . The short circuit preventing portion S 4 may be formed in the form of a groove, which is capable of accommodating a flow of a foreign material, so as to block the flow of the foreign material that is about to flow from the terminal plate 211 to the insulation member 412 . Accordingly, an electrical short circuit due to the flow of the foreign material flowing from the terminal plate 211 onto the cap plate 100 may be blocked.
The short circuit preventing portion S 4 may be formed to a depth extending from an exposed upper surface 211 a of the terminal plate 211 toward a lower surface 211 b facing the cap plate 100 , and may be formed along a side surface 211 c of the terminal plate 211 . According to another embodiment of the present invention, the short circuit preventing portion S 4 may be formed to a depth to pass through the terminal plate 211 , that is, up to the lower surface 211 b of the terminal plate 211 .
The short circuit preventing portion S 4 may be selectively formed in a portion along a boundary of the terminal plate 211 or may be formed in the form of a closed loop along the entire boundary of the terminal plate 211 . For example, as illustrated in FIG. 7A , the terminal plate 211 may have a rectangular shape including a pair of short side portions and a pair of long side portions, or the short circuit preventing portion S 4 may be selectively formed on one pair of short side portions. However, the short circuit preventing portion S 4 according to the embodiments of the present invention is not limited thereto, and may also be formed in the form of a closed loop along the rectangular boundary of the terminal plate 211 .
At least two of the short circuit preventing portions S 1 , S 2 , and S 3 having different forms illustrated in FIGS. 4A, 5A, and 6A may be formed in combination on one of the insulation members 112 , 212 , and 312 . FIGS. 8A, 8B, 9, 10, 11A, and 11B respectively illustrate insulation members 512 , 612 , 712 , and 812 according to embodiments of the present invention. Hereinafter, a structure in which at least two different short circuit preventing portions among short circuit preventing portions S 21 , S 22 , S 31 , S 32 , S 41 , S 42 , S 51 , S 52 , and S 53 are combined on one insulation member will be described with reference to FIGS. 8A, 8B, 9, 10, 11A, and 11B .
FIGS. 8A and 8B illustrate an insulation member 512 according to an embodiment of the present invention. FIG. 8B is a cross-sectional view of FIG. 8A .
Short circuit preventing portions S 21 and S 22 illustrated in FIGS. 8A and 8B may comprise a first short circuit preventing portion S 21 having an inclined upper surface 512 a and a second short circuit preventing portion S 2 in the form of a protrusion protruded from the upper surface 512 a of the insulation member 512 . For example, a flow of a foreign material may be limited within a terminal plate 311 via the inclined surface of the first short circuit preventing portion S 21 and the protrusion of the second short circuit preventing portion S 22 , and the flow of the foreign material to an outer portion of the terminal plate 311 may be blocked.
FIG. 9 illustrates an insulation member 612 according to another embodiment of the present invention.
Short circuit preventing portions S 31 and S 32 illustrated in FIG. 9 may comprise a first short circuit preventing portion S 31 having an inclined upper surface 612 a and a second short circuit preventing portion S 32 having a stepped side surface 612 c . For example, a flow of a foreign material may be limited within a terminal plate 311 via the inclined surface of the first short circuit preventing portion S 31 , and even if the foreign material flows along the side surface 612 c of the insulation member 612 , a continuous flow of the foreign material may be blocked via the stepped side surface 612 c of the second short circuit preventing portion S 32 .
FIG. 10 illustrates an insulation member 712 according to another embodiment of the present invention.
Short circuit preventing portions S 41 and S 42 illustrated in FIG. 10 may comprise a first short circuit preventing portion S 41 in the form of a protrusion protruding from an upper surface 712 a of the insulation member 712 and a second short circuit preventing portion S 42 having a stepped side surface 712 c . For example, a flow of a foreign material may be limited within a terminal plate 311 via the protrusion of the first short circuit preventing portion S 41 , and even if the foreign material flows along a side surface of the insulation member 712 , a continuous flow of the foreign material may be blocked via the stepped side surface 712 c of the second short circuit preventing portion S 42 .
FIGS. 11A and 11B illustrate an insulation member 812 according to another embodiment of the present invention. FIG. 11B is a cross-sectional view of the insulation member 812 of FIG. 11A .
Short circuit preventing portions S 51 , S 52 , and S 53 illustrated in FIGS. 11A and 11B may comprise a first short circuit preventing portion S 51 having an inclined upper surface 812 a , a second short circuit preventing portion S 52 in the form of a protrusion protruding from the upper surface 812 a of the insulation member 812 , and a third short circuit preventing portion S 53 having a stepped side surface 812 c . For example, a flow of a foreign material may be limited within a terminal plate 311 via the inclined upper surface 812 a of the first short circuit preventing portion S 51 and the protrusion of the second short circuit preventing portion S 52 , and even if the foreign material flows along the side surface 812 c of the insulation member 812 , a continuous flow of the foreign material may be blocked via the stepped side surface 812 c of the third short circuit preventing portion S 53 .
In one embodiment, the secondary batteries illustrated in FIGS. 8A, 8B, 9, 10, 11A, and 11B may further include a short circuit preventing portion S 11 of the terminal plate 311 in addition to the short circuit preventing portions S 21 , S 22 , S 31 , S 32 , S 41 , S 42 , S 51 , S 52 , and S 53 of the insulation members 512 , 612 , 712 , and 812 .
That is, according to the embodiments illustrated in FIGS. 8A, 8B, 9, 10, 11A, and 11B , the short circuit preventing portions S 11 , S 21 , S 22 , S 31 , S 32 , S 41 , S 42 , S 51 , S 52 , and S 53 may comprise the short circuit preventing portions S 11 formed on the terminal plate 311 and the short circuit preventing portions S 21 , S 22 , S 31 , S 32 , S 41 , S 42 , S 51 , S 52 , and S 53 formed on the insulation members 512 , 612 , 712 , and 812 . In each of the embodiments of the present invention, the short circuit preventing portion S 11 which is in the form of a groove formed on the terminal plate 311 may provide accommodation space for accommodating a flow of a foreign material in the terminal plate 311 , and as the flow of the foreign material from the terminal plate 311 toward the insulation members 512 , 612 , 712 , and 812 is accommodated, the flow of the foreign material flowing along the cap plate 100 is blocked via the short circuit preventing portion S 11 . Consequently, an electrical short circuit between the terminal plate 311 and the cap plate 100 may be prevented. Moreover, as the short circuit preventing portions S 21 , S 22 , S 31 , S 32 , S 41 , S 42 , S 51 , S 52 , and S 53 are further formed on the insulation members 512 , 612 , 712 , and 812 which surrounds the terminal plate 311 , the flow of the foreign material flowing along the insulation members 512 , 612 , 712 , and 812 may be blocked, and a short circuit between the terminal plate 311 and the cap plate 100 may be prevented.
For example, according to the embodiment illustrated in FIGS. 8A and 8B , the short circuit preventing portions S 11 , S 21 , and S 22 may comprise a first short circuit preventing portion S 21 having the inclined upper surface 512 a of the insulation member 512 , a second short circuit preventing portion S 22 in the form of a protrusion protruding from the upper surface 812 a of the insulation member 812 , and a third short circuit preventing portion S 11 in the form of a groove portion formed in the terminal plate 311 . The third short circuit preventing portion S 11 may be formed to a predetermined depth from an upper surface 311 a of the terminal plate 311 .
For example, according to the embodiment of FIG. 9 , the short circuit preventing portions S 11 , S 21 , and S 22 may comprise a first short circuit preventing portion S 21 having the inclined upper surface 512 a of the insulation member 512 , a second short circuit preventing portion S 22 in the form of a protrusion protruding from the upper surface 812 a of the insulation member 812 , and a third short circuit preventing portion S 11 in the form of a groove portion formed in the terminal plate 311 .
For example, according to the embodiment of FIG. 10 , the short circuit preventing portions S 11 , S 41 , and S 42 may comprise a first short circuit preventing portion S 41 in the form of a protrusion protruding from the upper surface 712 a of the insulation member 712 and a second short circuit preventing portion S 42 having the stepped side surface 712 c of the insulation member 712 , and a third short circuit preventing portion S 11 in the form of a groove portion formed in the terminal plate 311 .
For example, according to the embodiment of FIGS. 11A and 11B , the short circuit preventing portions S 11 , S 51 , S 52 , and S 53 may comprise a first short circuit preventing portion S 51 having the inclined upper surface 812 a of the insulation member 812 , a second short circuit preventing portion S 52 in the form of a protrusion protruding from the upper surface 812 a of the insulation member 812 , and a third short circuit preventing portion S 11 having the stepped side surface 812 c , and a fourth short circuit preventing portion S 11 in the form of a groove portion formed in the terminal plate 311 .
In one embodiment, while not shown in the drawings, the short circuit preventing portions S 1 , S 2 , and S 3 of the insulation members 112 , 212 , and 312 illustrated in FIGS. 4A, 5A, and 6A and the short circuit preventing portion S 4 of the terminal plate 211 illustrated in FIG. 7A may be applied in combination to a single secondary battery, and illustration and description of detailed structures thereof will be omitted here.
In one embodiment, according to an embodiment of the present invention, the first terminal plates 111 , 211 , and 311 and the cap plate 100 have different polarities, and the second terminal plate 121 and the cap plate 100 may have the same polarity. Accordingly, the short circuit preventing portions S 21 , S 22 , S 31 , S 32 , S 41 , S 42 , S 51 , S 52 , and S 53 may be formed on the first terminal plate 111 , 211 , and 311 and/or the insulation members 112 , 212 , 312 , 412 , 512 , 612 , 712 , and 812 surrounding the first terminal plate 111 , 211 , and 311 , thereby preventing an electrical short circuit between the first terminal plate 111 , 211 , and 311 and the cap plate 100 . In this case, as the second terminal plate 121 and the cap plate 100 have the same polarity, a short circuit preventing portion may be omitted in the second terminal plate 121 .
According to another embodiment of the present invention, the first terminal plate 111 , 211 , and 311 and the second terminal plate 121 may both have a different polarity from the cap plate 100 . Here, the short circuit preventing portion S 1 , S 2 , S 3 , S 4 , S 11 , S 21 , S 22 , S 31 , S 32 , S 41 , S 42 , S 51 , S 52 , and S 53 may be formed on the first terminal plate 111 , 211 , and 311 in order to prevent an electrical short circuit between the first terminal plate 111 , 211 , and 311 and the cap plate 100 . In addition, another short circuit preventing portions S 1 , S 2 , S 3 , S 4 , S 11 , S 21 , S 22 , S 31 , S 32 , S 41 , S 42 , S 51 , S 52 , and S 53 may be formed on the second terminal plate 121 in order to prevent an electrical short circuit between the second terminal plate 121 and the cap plate 100 . That is, a pair of short circuit preventing potions S 1 , S 2 , S 3 , S 4 , S 11 , S 21 , S 22 , S 31 , S 32 , S 41 , S 42 , S 51 , S 52 , and S 53 may be formed on the first and second terminal plates 111 , 211 , 311 , and 212 . The pair of the short circuit preventing potions S 1 , S 2 , S 3 , S 4 , S 11 , S 21 , S 22 , S 31 , S 32 , S 41 , S 42 , S 51 , S 52 , and S 53 formed on the first and second terminal plates 111 , 211 , 311 , and 212 may have various structures as described above, and the pair of the short circuit preventing potions S 1 , S 2 , S 3 , S 4 , S 11 , S 21 , S 22 , S 31 , S 32 , S 41 , S 42 , S 51 , S 52 , and S 53 may have the same structure or different structures.
It should be understood that the exemplary embodiments described therein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments.
Explanation of Reference numerals
100: cap plate
110: first electrode terminal
111, 211, 311: first terminal plate
121: second terminal plate
112, 212, 312, 412, 512, 612, 712, 812: insulation member
113, 123: seal gasket
114, 124: lower insulation member
115, 125: collector terminal
115a, 125a: collector terminal
115b, 125b: collector terminal
fixing portion
flange portion
117, 127: collector member
117a, 127a: lead portion
117b, 127b: collector plate
150: electrode assembly
151: first electrode plate
152: second electrode plate
153: separator
120: second electrode terminal
H1: height of terminal plate
H2: height of short circuit preventing
portion
S1, S2, S3, S4, S11, S21, S22, S31, S32, S41, S42, S51, S52, S53: short
circuit preventing portion | A secondary battery includes an electrode assembly; a case accommodating the electrode assembly; a cap plate sealing the electrode assembly within the case; a terminal plate on the cap plate and electrically connected to the electrode assembly; and an insulation member between and contacting the cap plate and the terminal plate, wherein the insulation member has a peripheral flange that extends away from the terminal plate. | 7 |
FIELD OF THE INVENTION
This invention relates to a surgical stapling device.
BACKGROUND
Surgical stapling devices have been in existence for many years. They are routinely used in surgical procedures mainly for the purposes of effecting a wound closure. Some of the most popular applications include closing a skin incision end-to-end or end-to-side anastomosis of internal (generally tubular) vessels such as the large bowel, etc. Current staplers are designed to deliver one or more staples in a serial fashion or a number of staples in one shot. Skin staplers, for example, deliver 30 or more staplers in a serial fashion. The staples are stacked within the device and during the firing operation one staple is advanced from the stack and delivered through the head of the device. During the following cycle another staple is advanced from the top of the stack and again delivered through the head of the device and so on. In one shot devices such as a bowel anastomosis stapler the staples are prearranged in a linear or circular fashion and upon activation of the device all the staples are delivered through the head. Examples of existing prior art as described above include U.S. Pat. Nos. 4,592,498, 5,289,963, 5,433,721 and 5,470,010.
The mechanism involved in forming a staple and releasing it from its forming mechanism is common to the majority of surgical stapler devices. Generally the components include an anvil, a staple closing actuator, and a staple release mechanism. The anvil is normally positioned in front of the staple and the actuator directly behind the staple. As the actuator advances the staple against the anvil the back section of the staple deforms around both ends of the anvil thereby transforming the staple from a generally U-shape to a generally rectangular shape. At this point the actuator generally retracts and the staple is released from the anvil either as a result of the anvil moving out of position and allowing the staple to move forward, or alternatively ejecting the staple over the anvil thereby releasing it from the device.
There are a number of problems associated with the mechanism as described above. Firstly, as the anvil is normally positioned in front of the staple it naturally becomes trapped between the back of the staple and the tissue into which it is being delivered causing the staple back to be spaced away from the tissue as opposed to lying tightly on its surface. This is a particular problem in the field of vascular puncture closure when it is desirable to keep the legs of the staple as short as possible so as to avoid having the legs of the staple within the vessel lumen.
Secondly, the method of releasing the staple from the anvil can be both complicated and unreliable. Metal springs are normally used which eject the staple over the anvil thereby affecting its release. However, should the spring fail to operate or is prohibited from operating properly by virtue of some tissue blockage etc, the device will become trapped in-situ.
Alternative release mechanisms include mechanical means of moving the anvil so that it is no longer in the path of the staple as it releases from the device. Again this generally involves very small metal components with relatively small movements which can fail to operate thereby leaving the staple trapped within the device and attached to the tissue into which it has been delivered.
Therefore there is a need for an improved surgical stapling device which will facilitate closer approximation of the staple back onto the surface of the vessel into which the staple is being delivered and a method of deforming the staple which does not include the use of an anvil component and therefore will not require the use of other components or mechanisms to facilitate the release of the staple from the anvil.
SUMMARY OF THE INVENTION
According to the present invention there is provided a surgical stapling device comprising an elongate housing, a surgical staple slidable longitudinally within the housing towards a free forward end thereof, the staple having a back and two forwardly pointing legs, an actuator slidable forwardly within the housing for driving the staple towards the free end of the housing, means for restraining the back of the staple against forward movement beyond a predetermined point such that further forward movement of the actuator bends the staple to bring the free ends of the legs towards one another to close the staple, and means for releasing the closed staple, wherein the back of the staple has a rearward extension and the restraining means comprises means for restraining the extension.
In a preferred embodiment the rearward extension is rupturably joined to the back of the staple, the staple being released by forward movement of the actuator beyond the point at which the staple is closed while the extension is restrained, thereby to rupture the join.
In another preferred embodiment a rearward extension is created which is integral to the staple back. This rearward extension creates a slot into which one end of an extension component is connected. Once the former has formed the staple around the anvil the extension is released from the staple during rearward movement of the former.
The benefits of the invention over conventional stapling devices is that, firstly, as no anvil is required the staple can be advanced forward to a position where the staple back is in direct contact with the tissue being stapled. This is of particular advantage when the staple legs must remain short but the level of penetration into the tissue must be assured. Secondly, because there is no anvil component involved in the delivery mechanism, there is no requirement to add additional components so as to facilitate ejection of the staple over or around the anvil component or alternatively to move the anvil component to a position which allows the staple to advance forward and free up the device.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a perspective view of a staple with a restraining plate for use in an embodiment of the invention;
FIGS. 2( a ) to 2 ( d ) are plan views (left hand column) and equivalent sectional views (right hand column) of a stapling device according to the embodiment in successive stages of operation;
FIG. 3 is a perspective view of the staple and actuator assembly of FIG. 2 ;
FIG. 4 is a perspective view of the forward tip of the actuator of FIG. 2 ; and
FIGS. 5 to 12 are perspective view of further embodiments of staple for use with a device according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
In the drawings the same reference numerals have been used for the same or equivalent parts.
Referring to FIGS. 1 to 4 , a surgical stapling device comprises an elongated housing or shaft 10 having upper and lower halves 10 a and 10 b defining between them a longitudinal channel 12 for slidably accommodating a staple 14 and a staple closing actuator 16 (in the plan views in the left hand column of FIG. 2 only the lower housing half 10 b is shown). Only the free forward end of the housing 10 is shown in the drawings, since that is where the invention lies in the present embodiment. The rear end of the housing 10 is preferably formed with a pistol grip and the movement of the various components to be described may be effected by a trigger acting through a cam system. Such an arrangement is described in Irish Patent Application S2000/0722 which may be readily adapted to operate the device of the present embodiment.
The staple 14 is generally U-shaped, having a back 18 and two forwardly pointing legs 20 . The free ends of the staple legs 20 are sharpened for ease of tissue penetration. Integral with the staple back 18 there is a rearwardly extending plate 22 which is attached to the upper edge of the centre section 18 a of the staple back by a pair of narrow, relatively weak tabs 24 . The tabs are effectively thin metal bridges which connect the staple back to the plate 22 . At the rear end of the plate 22 there is an upstanding flange 30 perpendicular to the plane of the plate 22 . In this embodiment the staple 14 including the plate 22 and flange 30 is made as an integral structure from stamped and bent sheet metal stock, for example, a malleable metal or metal alloy such as stainless steel or titanium.
Adjacent to the tabs 24 , at the junctions 26 between the centre section 18 a and the outer sections 18 b of the staple back on either side, and where in use the staple back is designed to bend through an angle of 90° as will be described, local deformation of the material of the staple is provided so as to ensure that bending takes place preferentially at those points.
The actuator 16 is an elongated rod having a forward end which is forked to provide two arms 28 separated by a recess 34 . The lateral separation of the arms 28 is slightly greater than the distance between the junctions 26 on the back 18 of the staple.
The device is assembled ( FIG. 2 ) with the actuator 16 extending longitudinally in the channel 12 with its forked end facing towards the free forward end of the housing 10 . The staple 14 is positioned freely in front of the actuator 16 with its back 18 transverse to the axis of the housing 10 with the plate 22 extending rearwardly across the top surface of the actuator. The flange 30 extends up into a recess 32 in the top housing half 10 a. The actuator arms 28 are behind and in alignment with the outer sections 18 b of the staple back.
In use, both the staple 14 and the actuator 16 are initially retracted, FIG. 2( a ), so that the flange 30 is adjacent the rear end of the recess 32 and the entire staple 14 is contained wholly within the housing 10 . Upon operation of the trigger previously mentioned, or other operating mechanism, the actuator 16 is driven forwardly towards the free forward end of the housing 10 . This drives the staple 14 before it by engagement of the actuator arms 28 with the outer sections 18 b of the staple back.
At a predetermined point, FIG. 2( b ), where the back of the staple is substantially level with the forward end of the housing 10 , the flange 30 comes up against the front end of the recess 32 . The flange 30 and front end of the recess 32 act as cooperating stop means which, via the plate 22 , restrain the centre section 18 a of the staple back against further forward movement. Thus, as the actuator 16 continues to advance, the actuator arms 28 bend the outer sections 18 b of the back of the staple forwardly through 90° to bring the free ends of the staple legs 20 towards one another and deform the staple into a generally rectangular closed shape, FIG. 2( c ).
At this point the base 36 of the recess 34 in the front of the actuator 16 is abutting against the centre section 18 a of the staple base. Now, since the plate 22 remains restrained by engagement of the stop means 30 / 32 further forward movement of the actuator 16 will rupture the tabs 24 thus freeing the staple from the plate 22 . At this point the cycle is complete.
FIG. 5 shows an alternative embodiment for the staple. It comprises a standard round wire staple 40 having a rearwardly extending restraining plate 22 with upstanding flange 30 attached to the centre section of the staple back by rupturable tabs 24 . The tabs may be attached to the staple back by soldering, braising, laser welding, adhesive bonding, etc. The preferred process will ensure a consistent break-off force between the tabs and the staple back.
Referring now to FIG. 6 , another embodiment of the staple is shown which includes two staples 14 disposed spaced apart one above and each having a respective rearwardly-extending restraining plate 22 joined thereto by rupturable tabs as previously described. In this case the rear ends of the parallel plates are joined by a common flange 30 . In such a case the stapling device would be modified such that stop means on the housing 10 projected into the space between the upper and lower plates 22 and engaged the flange 30 between them to restrain the back of the staple. The double staple could be driven by two actuators 16 , one disposed above the upper plate 22 and the other below the lower plate 22 , or a single actuator could be used having upper and lower branches which embrace the plates 22 between them.
FIG. 7 shows another staple usable in the invention in which the centre section 18 a of the staple back is enlarged, for example by forming it as a disk 42 , so that the centre section 18 a has a much greater area in a plane normal to the longitudinal axis of the housing 10 than either of the outer section 18 b. This configuration has particular application in the field of vascular puncture closure. The process of closing puncture holes using conventional staples may be enhanced using this method as the disk 42 on the staple back provides greater surface coverage of the puncture hole area thereby effecting haemostasis in a shorter time.
FIG. 8 shows a configuration which is essentially the double staple as described in FIG. 6 but for use in combination with a stapling device having a locator tube 44 . The locator tube 44 , which passes between the plates 22 through a hole (not shown) in the flange 30 , is slidable axially within the housing 10 between a forward position wherein it projects beyond the free forward end of the housing 10 to enter a puncture site in a liquid-carrying vessel in a human or animal, thereby to locate the free end of the housing at the puncture site, and a rearward position wherein the locator tube is retracted into the housing. In use a guidewire (not shown) extends within the locator tube and emerges from the forward end of the tube, the tube 44 being tracked along the guidewire to the puncture site and the guidewire and tube being retracted into the housing prior to closure of the staples. A locator tube is described in the aforementioned Irish Patent Application S2000/0722, and it will be clear to one skilled in the art how to modify the embodiment shown in FIG. 2 to incorporate such a tube. This configuration has particular relevance in the area of vascular puncture closure.
The staple configurations shown in FIGS. 6 to 8 are, like the staple shown in FIG. 1 , designed so that they are easily manufactured as integral structures from sheet metal using a conventional metal stamping and bending processes.
The embodiment of staple shown in FIG. 9 comprises a staple essentially as described with reference to FIG. 7 but without the attached plate 22 . Instead, a rearwardly extending filament 46 is attached to the rear surface of the disk 42 . In use, the stapling device is adapted to trap or hold the rear end of the filament 46 so that it becomes taut at the point where the staple back is level with the front end of the housing 10 so that further advance of the actuator will bend the outer sections 18 b of the staple back to close the staple as previously described. At this point the actuator may advance further forward thereby shearing or detaching the filament from the back surface of the disk 42 . Alternatively, the actuator may retract while simultaneously the device releases the filament at its rear end and consequently releasing the staple from the device. Examples of the filament material are Dacron, PLA, PGA and PLGA.
In FIG. 10 a staple configuration is shown similar to that in FIG. 3 except that the rupture tabs 24 are replaced with a slotted tab 50 which engages with an upstanding flange 52 integral to plate 22 . As the former advances forward to form the staple the back is held in position by the plate 22 . Once forming is complete the former component retracts while simultaneously causing the plate 22 to move down disengaging the flange 52 from the staple slot 50 allowing it to separate from the stapler device.
FIGS. 11 and 12 illustrate further embodiments of this principle. In FIG. 11 the flange 52 engages a band 54 which is formed integrally with an lies parallel to the back 18 of the staple. In FIG. 12 a pair of L-shaped cylindrical arms engage a channel section 58 of the staple back 18 to restrain the staple during forming. When forming is complete the former retracts while simultaneously causing the arms 56 to be pushed outwards, away from one another and out of engagement with the channel section 58 .
The invention is not limited to the embodiments described herein and may be modified or varied without departing from the scope of the invention. | A surgical stapler comprises an elongate housing 10 and a surgical staple 14 slidable longitudinally within the housing towards the free forward end thereof. The back 18 of the staple has a rearward extension 22. An actuator 16 is slidable forwardly within the housing for driving the staple towards the free end of the housing. An upstanding flange 30 on the extension 22 engages a stop 32 within the housing to restrain the back of the staple against forward movement of the actuator bends the staple to bring the free ends of the legs towards one another to close the staple. Further movement of the actuator then ruptures the join between the extension and the back of the staple to release the closed staple. | 0 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to integrated circuit (IC) devices, and in particular to a lateral double diffused metal-oxide-semiconductor (LDMOS) device and a method for fabricating the same.
2. Description of the Related Art
Recently, due to the rapid development of communication devices such as mobile communication devices and personal communication devices, wireless communication products such as mobile phones and base stations have been developed greatly. In wireless communication products, high-voltage elements of lateral double diffused metal-oxide-semiconductor (LDMOS) devices are often used as radio frequency (900 MHz-2.4 GHz) related elements therein.
LDMOS devices not only have a higher operation frequency, but they are also capable of sustaining a higher breakdown voltage, thereby having a high output power so that they can be used as power amplifiers in wireless communication products. In addition, due to the fact that LDMOS devices can be formed by conventional CMOS fabrications, LDMOS devices can be fabricated from a silicon substrate which is relatively cost-effective and employs mature fabrication techniques.
In FIG. 1 , a schematic cross section showing a conventional N-type lateral double diffused metal-oxide-semiconductor (LDMOS) device applicable in a radio frequency (RF) circuit element is illustrated. As shown in FIG. 1 , the N-type LDMOS device mainly comprises a P+ type semiconductor substrate 100 , a P− type epitaxial semiconductor layer 102 formed over the P+ type semiconductor substrate 100 , and a gate structure G formed over a portion of the P− type epitaxial semiconductor layer 102 . A P− type doped region 104 is disposed in the P− type epitaxial semiconductor layer 102 under the gate structure G and a portion of the P− type epitaxial semiconductor layer 102 under the left side of the gate structure G, and a N− type drift region 106 is disposed in a portion of the P− type epitaxial semiconductor layer 102 under the right side of the gate structure G. A P+ type doped region 130 and a N+ type doped region 110 are disposed in a portion of the P type doped region 104 , and the P+ doped region 130 partially contacts a portion of the N+ type doped region 110 , thereby functioning as a contact region (e.g. P+ type doped region 130 ) and a source region (e.g. N+ type doped region 110 ) of the N type LDMOS device, respectively, and another N+ type doped region 108 is disposed in a portion of the P− type epitaxial semiconductor layer 102 at the right side of the N− type drift region 106 to function as a drain region of the N type LDMOS device. In addition, an insulating layer 112 is formed over the gate structure G, covering sidewalls and a top surface of the gate structure G and partially covering the N+ type doped regions 108 and 110 adjacent to the gate structure G. Moreover, the N type LDMOS further comprises a P+ type doped region substantially disposed in a portion of the P− type epitaxial semiconductor layer 102 under the N+ type doped region 110 and the P− type doped region 104 under the N+ type doped region 110 . The P+ type doped region 120 physically connects the P− type doped region 104 with the P+ type semiconductor substrate 100 .
During operation of the N type LDMOS device shown in FIG. 1 , due to the formation of the P+ type doped region 120 , currents (not shown) from the drain side (e.g. N+ type doped region 108 ) laterally flow through a channel (not shown) underlying the gate structure G towards a source side (e.g. N+ type doped region 110 ), and are then guided by the P− type doped region 104 and the P+ type doped region 120 , thereby arriving the P+ type semiconductor substrate 100 , such that problems such as inductor coupling and cross-talk between adjacent circuit elements can be avoided. However, formation of the P+ type doped region 120 needs to perform ion implantations of high doping concentrations and high doping energies and thermal diffusion processes with a relatively high temperature above about 900° C., and a predetermined distance D1 is kept between the gate structure G and the N+ type doped region 110 at the left side of the gate structure G to ensure good performance of the N type LDMOS device. Therefore, formation of the P+ type doped region 120 and the predetermined distance D1 kept between the gate structure G and the N+ type doped region 110 increase the on-state resistance (Ron) of the N type LDMOS device and a dimension of the N type LDMOS device, which is unfavorable for further reduction of both the fabrication cost and the dimensions of the N type LDMOS device.
BRIEF SUMMARY OF THE INVENTION
Accordingly, an improved lateral double diffused metal oxide semiconductor (LDMOS) device and method for fabricating the same are provided to reduce size and fabrication cost.
An exemplary lateral double diffused metal oxide semiconductor (LDMOS) device comprises: a semiconductor substrate, having opposite first and second surfaces and a first conductivity type; a well region formed in a portion of the semiconductor substrate adjacent to the first surface thereof, having the first conductivity type; a gate structure disposed over a portion of the first surface of the semiconductor substrate; a first doped region disposed in a portion of the well region adjacent to a first side of the gate structure, having the first conductivity type; a second doped region disposed in a portion of the well region adjacent to a second side of the gate structure opposite to the first side, having a second conductivity type opposite to the first conductivity type; a third doped region disposed in a portion of the first doped region, having the second conductivity type; a fourth doped region disposed in a portion of the second doped region, having the second conductivity type; a first trench formed in a portion of the third doped region, the first doped region, the well region, and the semiconductor substrate; a conductive contact formed in the first trench; a second trench formed in a portion of the semiconductor substrate adjacent to the second surface thereof, wherein the second trench exposes a portion of the conductive contact; a first conductive layer formed in second trench, contacting the conductive contact; and a second conductive layer formed over the second surface of the semiconductor substrate and the first conductive layer.
An exemplary method for fabricating a lateral double diffused metal oxide semiconductor (LDMOS) device comprises: performing a semiconductor substrate, having opposite first and second surfaces and a first conductivity type; performing an ion implantation process, forming a well region in a portion of the semiconductor substrate adjacent to the first surface thereof, having the first conductivity type; forming a gate structure over a portion of the well region; forming a first doped region in a portion of the well region adjacent to a first side of the gate structure, having the first conductivity type; forming a second doped region in a portion of the well region at a second side of the gate structure opposite to the first side, having a second conductivity type opposite to the first conductivity type; forming a third doped region in a portion of the first doped region, having the second conductivity type; forming a fourth doped region in a portion of the second doped region, having the second conductivity type; forming a trench in a portion of the third doping region, the first doped region, the well region, and the semiconductor substrate; forming a conductive contact in the first trench; thinning the semiconductor substrate from the second surface thereof; after thinning the semiconductor substrate, forming a second trench in a portion of the semiconductor substrate adjacent to the second surface thereof, exposing a portion of the conductive contact; forming a first conductive layer in the second trench; and forming a second conductive layer over the second surface of the semiconductor substrate and the first conductive layer.
A detailed description is given in the following embodiments with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
FIG. 1 is schematic cross section of a conventional lateral double diffused metal-oxide-semiconductor (LDMOS) device; and
FIGS. 2-6 are schematic cross sections showing a method for fabricating a lateral double diffused metal-oxide-semiconductor (LDMOS) device according to an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.
FIGS. 2-6 are schematic cross sections showing a method for fabricating a lateral double diffused metal-oxide-semiconductor (LDMOS) device applicable for a radio frequency (RF) circuit element according to an embodiment of the invention.
Referring to FIG. 2 , a semiconductor substrate 200 such as a silicon substrate is first provided. In one embodiment, the semiconductor substrate 200 has a first conductivity type such as a P type conductivity, and a resistivity of about 5 ohms-cm (Ω-cm)-15 ohms-cm (Ω-cm). The semiconductor substrate 200 has opposing surfaces A and B. Next, a sacrificial layer 202 is formed over the surface A of the semiconductor substrate 202 . In one embodiment, the sacrificial layer 202 may comprise materials such as silicon oxide and may be formed by a deposition process (not shown) such as thermal oxidation. Next, an ion implantation process 204 is performed to the semiconductor substrate 200 to implant dopants of the first conductivity type through the sacrificial layer 202 and into a portion of the semiconductor substrate 200 , thereby forming a doped region 206 . In one embodiment, the dopants of the first conductive type implanted by the ion implantation process 204 can be, for example, dopants of P-type conductivity.
In FIG. 3 , a thermal process (not shown) is performed to diffuse the dopants in the doped region 206 , thereby forming a well region 208 in the semiconductor substrate 200 . Herein, the well region 208 comprises dopants of the first conductivity type, and has a resistivity of about 0.5 ohms-cm (Ω-cm)-1 ohms-cm (Ω-cm). In one embodiment, the resistivity of the well region 208 is lower than the resistivity of the semiconductor substrate 200 . Next, the sacrificial layer 202 over the surface A of the semiconductor substrate 200 is removed, and a patterned gate structure G is formed over a portion of the surface A of the semiconductor substrate 200 . The gate structure G mainly comprises a gate dielectric layer 210 , a gate electrode 212 , and a hard mask layer 214 sequentially formed over a portion of the semiconductor substrate 200 . The gate dielectric layer 210 , the gate electrode 212 , and the hard mask layer 214 of the gate structure G can be formed by conventional gate processes and related materials, and are not described here in detail for the purpose of simplicity. Next, a plurality of suitable masks (not shown) and a plurality of ion implant processes (not shown) are then performed to form a doped region 216 in a portion of the semiconductor substrate 200 at the left side of the gate structure G, and a doped region 218 in a portion of the semiconductor substrate 200 at the right side of the gate structure G. In one embodiment, the doped region 216 has a first conductivity type such as P type, and the doped region 218 has a second conductivity type such as N type opposite to the P type, and the ion implant processes (not shown) for forming the doped regions 216 and 218 can be ion implant processes with tilted implantation angles. Next, another suitable implant mask (not shown) and an ion implantation process (not shown) are performed to form a doped region 220 and a doped region 222 in a portion of the doped regions 216 and 218 , respectively, on opposite sides of the gate structure G, and the configuration shown in FIG. 3 is formed after performing a thermal diffusion process (not shown). In one embodiment, the doped region 220 formed in a portion of the doped region 216 and the doped region 222 formed in a portion of the doped region 218 respectively has the second conductivity type, such as N type, and the ion implant process (not shown) for forming the doped regions 220 and 222 can be an ion implantation vertical to the surface A of the semiconductor substrate 200 . In one embodiment, the doped region 218 may function as a drift region, and the doped regions 220 and 222 may function as source and drain regions, respectively.
In FIG. 4 , an insulating layer 224 is next formed over the semiconductor substrate 200 , and the insulating layer 224 conformably covers the surface A of the semiconductor substrate 200 and a plurality of sidewalls and a top surface of the gate structure G formed thereover. Next, a patterning process (not shown) is performed to form an opening 226 in a portion of the insulating layer 224 . As shown in FIG. 4 , the opening 226 exposes a portion of the doped region 220 such that other portions of the semiconductor substrate 200 and surfaces of the gate structure G are still covered by the insulating layer 224 . In one embodiment, the insulating layer 224 may comprise insulating materials such as silicon oxide and silicon nitride, and can be formed by a method such as chemical vapor deposition (CVD). Next, an etching process (not shown) is performed, using the insulating layer 224 as an etching mask, thereby forming a trench 228 in the semiconductor substrate 200 exposed by the opening 226 . The trench 228 is formed with a depth H which mainly penetrates a portion of the doped region 220 , the doped region 216 , the well region 208 , and the semiconductor substrate 200 . A conductive layer 230 and another conductive layer 232 are then sequentially deposited, wherein the conductive layer 230 conformably forms over surfaces of the insulating layer 224 and the bottom surface and the sidewalls of the semiconductor substrate 200 exposed by the trench 228 , and the conductive layer 232 is formed over the surfaces of the conductive layer 230 , thereby filling the trench 228 . Next, the conductive layers 230 and 232 are patterned by using a suitable patterning mask and a patterning process (both not shown). As shown in FIG. 4 , the patterned conductive layers 230 and 232 are formed over the insulating layer 224 adjacent to the trench 228 , extending over the bottom surface and the sidewalls of the trench 228 , thereby covering surfaces of the well region 208 , and the doped regions 216 , 220 exposed by the trench 228 , and the conductive layers 230 and 232 also cover the gate structure G and a portion of the doped region 218 adjacent to the gate structure G. However, the conductive layers 230 and 232 do not cover the doped region 222 . The portion of the conductive layers 230 and 232 formed in the trench 228 may function as a conductive contact. In one embodiment, the conductive layer 230 may comprise conductive materials such as Ti—TiN alloy, and the conductive layer 232 may comprise conductive materials such as tungsten.
In FIG. 5 , a dielectric material such as silicon oxide or spin-on-glass (SOG) is deposited over the conductive layers 230 and 232 , such that the dielectric material covers the conductive layer 232 , the insulating layer 224 , and the gate structure G, thereby forming an inter-layer dielectric (ILD) layer 234 with a substantially planar top surface. Next, a patterning process (not shown) comprising photolithography and etching steps is performed to form a trench 236 in a portion of the ILD layer 234 and the insulating layer 224 over a portion of the doped region 222 , and the trench 236 exposes a portion of the doped region 222 . Next, a conductive layer 238 and another conductive layer 240 are sequentially deposited, and the conductive layer 238 conformably forms over the surfaces of the ILD layer 234 and the sidewalls exposed by the trench 236 , and the conductive layer 240 is formed over the surface of the conductive layer 238 , thereby filling the trench 236 . The portion of the conductive layers 238 and 240 formed in the trench 236 may function as a conductive contact. In one embodiment, the conductive layer 238 may comprise conductive materials such as Ti—TiN alloy, and the conductive layer 240 may comprise conductive materials such as tungsten.
In FIG. 6 , a handling substrate (not shown) is used to bond with a surface of the conductive layer 240 and then the structure shown in FIG. 5 is reversed, and a thinning process (not shown) comprising steps such as etching, polishing or combinations thereof are then performed to reduce the thickness of the semiconductor substrate 200 from the surface B thereof. Herein, after the thinning process, the thinned semiconductor substrate 200 is assigned with a reference number 200 ′, and a thinned surface B′ of the thinned semiconductor substrate 200 ′ has a distance X to the bottom surface of the conductive layer 230 in the trench 228 . In one embodiment, the distance X is about 50-300 μm.
Next, a patterning process (not shown) is performed by using a suitable patterned mask layer (not shown), thereby forming a trench 242 in the surface B′ of the thinned semiconductor substrate 200 ′, and the trench 242 exposes the bottom surface and portions of the sidewalls of the conductive layer 230 . Next, a deposition process (not shown) is performed to form a conductive layer 244 in the trench 242 . In one embodiment, the conductive layer 244 may comprise conductive materials such as Ti—TiN alloy, tungsten, AlCu alloy, AlSiCu alloy, and may be formed by a deposition process such as physical vapor deposition (PVD) or chemical vapor deposition (CVD). The formed conductive layer 244 may be processed by a planarization process (not shown), such that a surface of the conductive layer 244 is coplanar with the surface B′ of the thinned semiconductor substrate 200 . Next, another deposition process (not shown) is performed to form a blanket conductive layer 246 over the surface of the conductive layer 244 and the surface of the thinned semiconductor substrate 200 ′. In one embodiment, the conductive layer 246 may comprise conductive materials such as Ti—Ni—Ag alloy, and may be formed by a method such as physical vapor deposition (PVD) or chemical vapor deposition (CVD). Therefore, after removal of the handling substrate (not shown), an exemplar LDMOS device is substantially fabricated, as shown in FIG. 6 .
In one embodiment, the gate structure G and the doped regions 220 and 222 of the LDMOS device shown in FIG. 6 may be properly electrically connected (e.g. through conductive layers 230 , 232 , 238 , and 240 ), and the regions with the first conductivity type can be P type regions, and the regions of the second conductivity type can be N type regions, such that the formed LDMOS device herein is an N type LDMOS device. At this time, the doped region 220 may function as a source region and the doped region 222 may function as a drain region. In this embodiment, during operation of the LDMOS device shown in FIG. 6 , currents from the drain side (e.g. the doped region 222 ) may laterally flow toward the source side (e.g. doped region 220 ), and then arrive at the surface B′ of the thinned semiconductor substrate 200 ′ by the guidance of the doped region 216 , the conductive layers 230 and 232 , and the conductive layer 244 , and are then dissipated by the conductive layer 246 , such that undesired problems such as inductor coupling and cross-talk between adjacent circuit elements can be prevented. In this embodiment, due to the formation of the conductive layers 230 and 232 formed in the trench 228 and the conductive layer 244 embedded in the thinned semiconductor layer 200 ′ contacting the conductive layer 246 , such that ion implantation with high dosages and high energies for forming the P+ type doped region 120 as shown in FIG. 1 can be avoided, a predetermined distance D2 between the gate structure G and the doped region 234 at the right side of the trench 232 can be less than the predetermined distance D1 as shown in FIG. 1 . Therefore, when compared with the N type LDMOS device as shown in FIG. 1 , the N type LDMOS device shown in FIG. 6 may have the advantages of reduced size and fabrication cost, and formation of the conductive layers 244 and 246 also helps to reduce the on-state resistance (Ron) of the N type LDMOS device.
In addition, in another embodiment, the regions with the first conductivity type of the LDMOS device shown in FIG. 6 can be N type regions, and the regions of the second conductivity type can be P type regions, such that the formed LDMOS device herein can be an P type LDMOS device.
While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements. | A LDMOS device includes a substrate having opposite first and second surfaces; a well region in a portion of the substrate; a gate structure over a portion of the substrate; a first doped region disposed in a portion of the well region from a first side; a second doped region disposed in the well region from a second side; a third doped region disposed in the first doped region; a fourth doped region disposed in the second doped region; a first trench in the third doped region, the first doped region, the well region, and the substrate adjacent to the first surface; a conductive contact in the first trench; a second trench in the substrate adjacent to the second surface; a first conductive layer in second trench; and a second conductive layer over the second surface of the substrate and the first conductive layer. | 7 |
The Government has rights in this invention pursuant to Contract No. DE-ACO3-76SF00098 awarded by the U.S. Department of Energy.
BACKGROUND OF THE INVENTION
The present invention relates to the photodissociation of chemical compounds by electrolytic means, and more particularly to such molecular dissociation reactions in an electrolytic cell wherein the electrodes are doped iron oxide.
During the past several decades there has been considerable interest and intense research in photochemical dissociation of chemical molecules, especially water. These studies have generally centered around chlorophyl mediated reactions which involve complex multistep reactions to achieve the photodissociation of water and the synthesis of various organic compounds. As a general outgrowth of research in this area, some studies have been undertaken into simpler photochemical systems which are capable, or potentially capable, of catalytically mediating the dissociation of chemical compounds into their respective elements. In this regard, one area of interest has been the photocatalytic dissociation water into its respective elements, oxygen and hydrogen by means of electrolytic processes. In such processes, currents are induced in semi-conductor materials by photon irradiation, and these currents, often with the assistance of externally applied potentials, have achieved low rate of dissociation of water. Fugishima et al reported in Nature 238, 37, 1972, that they achieved association, but only with the aid of an externally applied potential. F. T. Wagner et al. reported (J. Am. Chem. Soc. 102, 5444) in 1980 the photo dissociation of water utilizing strontium titanate single crystals or polycrystalline powders thereof. A. J. Nozik in 1976 (App. Phys. Letters 29, 150), and K. Ohashi et al., in 1977 (Nature 266, 610) reported that when n-type SrTiO 3 or TiO 2 , and p-type GaP or CdTe were used in an electrolytic cell as anode and cathode, respectively, and irradiated with ultraviolet energy, water was dissociated without using any externally applied electrical potentials.
H. Mettee et al. in 1981 (Solar Energy Mat. 4, 443) have reported that a p/n diode, consisting of single crystal p-type GaP and polycrystalline n-type Fe 2 O 3 , splits water at relatively low quantum yields when such diode was irradiated with visible and near ultra-violet light.
Such techniques, however, either require the addition of an externally applied potential to accomplish the dissociation; or they require radiation in the ultra-violet region; or they require electrodes fabricated from scarce rare elements, or carefully and expensively produced single crystals.
Therefore it is of considerable interest to devise processes for the photodissociation of water, or for the photo induced hydrogenation of CO, or CO 2 to produce hydrocarbons, etc., wherein the photo process relies upon visible light, does not require any externally applied electrical potentials, utilizes common, readily available electrode materials, and utilizes simple, and inexpensive fabrication techniques for the electrodes.
BRIEF DESCRIPTION OF THE INVENTION
The present invention provides a process for photo-electrolytic dissocation utilizing radiation in the visible solar range; wherein the electrolytic cell electrodes are fabricated from common, easily obtained, and inexpensive compounds; wherein the electrodes are fabricated in a simple, straightforward and inexpensive process; and wherein the photodissociation is accomplished solely by photo induced electrical potentials and without the aid of any externally applied electrical potentials.
More specifically, the dissociation of water is accomplished by the use of photoactive ferric oxide semi-conductor materials as electrodes in an electrolytic cell. The ferric oxide semi-conductor materials are prepared as a diode wherein one electrode, the cathode, is a p-type Fe 2 O 3 semi-conductor; and the other electrode, the anode, is an n-type Fe 2 O 3 semi-conductor. The cathode and anode are connected to one another by an insulated electrical connection, and the circuit is completed by immersing the electrodes in water as the electrolyte. In order to increase the conductance of the water, and to adjust the pH to from about 6 to 14 where the photo activity is greater, an ionizing component is added.
The cell is provided with a window to admit light to the electrodes. The admitted light may comprise solar radiation or an artificial source. The radiation must have an energy level at least equal to the band gap of α-Fe 2 O 3 , i.e., 2.2 eV, and preferably somewhat greater than that figure, e.g., energies between 2.2 and 2.9 eV, i.e., in the visible range.
The electrode materials are based on polycrystalline Fe 2 O 3 . The Fe 2 O 3 is doped to convert it into either an n-type semiconductor, or a p-type semiconductor. The n-type iron oxide is produced by doping with SiO 2 . The p-type iron oxide is produced by doping with MgO. All of the electrode components are readily available and they are inexpensive.
When a cell such as that described above is illuminated with visible light, a photocurrent is induced resulting in the dissociation of water as evidenced by the production of gaseous hydrogen on the cathode surface. So long as the illumination is maintained, dissociation of the water continues. However, after about 6-8 hours of exposure, H 2 production rate drops and the photocurrent declines. The H 2 production and photocurrent can be restored to their initial levels by flowing oxygen or air through the electrolyte for several (1-20) minutes.
Thus a useable photocurrent can be induced, and water can be dissociated, by shining visible light on an electrolytic cell having doped iron oxide electrodes and water as the electrolyte.
It is therefore an obect of the invention to provide an electrolytic cell for the dissociation of chemical compounds wherein the only source of energy is light.
It is another object of the invention to provide an electrolytic cell for the dissociation of chemical compounds wherein the dissociation is driven by visible light and the cell electrodes are fabricated from polycrystalline ferric oxide.
It is another object of the invention to provide electrodes for a photoelectrolytic cell wherein both the anode and cathode are fabricated from doped iron oxide.
It is yet another object of the invention to provide a process for the dissociation of chemical compounds utilizing a photoelectrolytic cell driven solely by visible light and wherein the chemical compounds are dissociated between doped ferric oxide electrodes.
It is another object of the invention to provide a p-type Fe 2 O 3 electrode useful in a photoelectrolytic cell.
Other objects and advantages of the invention will become apparent from the following specification, and the claims appended hereto.
DETAILED DESCRIPTION OF THE INVENTION
In the present invention chemical compounds, and, in particular water, are dissociated in an electrolytic cell wherein the chemical compound comprises, or partly comprises, the cell electrolyte. This electrolyte is in contact with an anode and a cathode especially devised to develop an electrical potential when irradiated with visible light. Of course the anode and cathode have an insulated electrical connection between them, and the electrolyte completes the electrical circuit. Such cell is capable of dissociating the chemical compounds without the aid of any externally applied electrical potential. That is, the cell, under conditions as hereinafter described develops sufficient electrical potential to cause dissociation of the chemical compound and the evolution of its constituent elements at the anode and cathode.
The electrodes are the key elements in the electrolytic cell and they comprise a p-type ferric oxide polycrystalline semi-conductor material as the cathode; and an n-type ferric oxide polycrystalline semi-conductor material as the anode. When maintained in electrical contact, the cathode and anode comprise a p/n semi-conductor diode.
The p-type ferric oxide cathode is a highly pure Fe 2 O 3 polycrystalline sintered compact that has been doped with a small percentage of MgO. For purposes of the invention the Mg may comprise from about 1 to about 20 atom percent Mg of the cathode material. It is preferred that the Mg comprise between about 5 and about 10 atom % of the cathode material, since the highest photocurrents are generated when these %'s are present.
The n-type ferric oxide anode is a highly pure Fe 2 O 3 polycrystalline sintered compact that has been doped with a small percentage of SiO 2 . The Si may comprise from about 1 to about 5 atom % Si in the doped material. At much below 1 atom % Si, the Fe 2 O 3 conductivity greatly decreases and the onset potential for photocurrent production becomes unacceptably high. Si dopings above 10 atom % produce no apparent improvement in either the conductivity or in the onset potentials.
It should be noted also, that the doped Fe 2 O 3 electrodes function in the invention process when in the polycrystalline form. Thus they can be produced in a relatively simple and inexpensive process (as will be discussed hereinafter) from pure iron oxide powders.
The doped ion oxide electrodes may be produced in any desired shape, but usually in the form of disks or thin films, so that the surface area to volume is high. Thus a greater surface will be available for contact with the electrolyte at the least cost for material.
To form a p/n diode, provision must be made to maintain the anode and cathode in electrical contact. The electrodes may be connected by means well known in the art. For instance an electrically conducting wire of Ag or Ni, etc., may be affixed at each of its ends to the respective electrode. An electrically conducting epoxy compound, such as Ag-epoxy, works quite well. In an alternate form, the anode and cathode may be bonded directly to one another, as by means of the silver-epoxy compound. The particular means of electrically connecting the anode to the cathode is not important so long as a low resistance electrical connection is maintained. The connection as well as the affixing means, e.g., silver-epoxy compound, should be insulated from the electrolyte. Therefore, these components are covered with a tightly adherent electrical insulation material, such as silicone rubber.
To optimize photocurrent production, it is advantageous to ensure high oxidation of the electrode surfaces. Therefore, it is desirable to subject the electrodes to oxidizing conditions before cell operation begins. This can be done by imposing an externally generated electrical potential on the electrodes for a short period of time to ensure oxidation of the iron component, or oxygen can be bubbled through the cell for the same purpose.
To complete the electrolytic cell, the doped Fe 2 O 3 diode is immersed in an electrolyte. The electrolyte includes the compound which is to be electrolysed. If water is to be dissociated, the electrolyte is, of course, water. However small amounts of a polar material are added to increase the electrolyte conductivity and maintain the pH between about 6 and 14. Where water is being dissociated, Na 2 SO 4 or NaOH may be added to maintain the pH in the desired range. Of course, other polar compounds could be used to increase the electrolyte conductivity, so long as they are not corrosive to the electrodes, and do not interfere with the electrochemical reactions that take place on the electrode surfaces.
The electrolytic cell need not be in any special configuration. It should be constructed of an inert material, e.g., glass, ceramic, plastic coated metals, etc. If the gases evolved from the electrodes are to be collected, the cell should be closed and provision for purging, or circulating the air space over the electrolyte must be made. However, all such structures form no part of this invention, and are well known in the art. Provision must be made, however, for shining light on the diode. Therefore, a window is provided, suitably made from quartz, to permit light into the cell interior.
As noted above, the illuminating light is in the visible range, having an energy of at least 2.2 eV, and up to about 2.2 eV or greater. The light intensity must be sufficient to initiate the desired photocurrent. In test cells, an incoming light intensity of about 35 mW on a 1 cm 2 surface area was quite sufficient to generate H 2 evolution at the cathode surface.
Other features of the invention, and some results obtained in experimental work, will be apparent from a review of the following.
Preparation of the Electrodes
The electrodes of the invention are prepared from powders of the components in a pressing and sintering procedure.
Fine powders having particle sizes averaging perhaps 1 to 10μ are utilized. The powders should be of high purity, 99.9% or better. All the powdered components, Fe 2 O 3 , SiO 2 , and MgO are available in the required purity from a number of commercial sources. For instance, the Fe 2 O 3 can be obtained from MCB Mfg. Chemists of Norwood, Oh. The SiO 2 and MgO powders can be obtained from Mallinkrodt Chemicals of Paris, Ky.
In any event, the powdered components are first mixed to thoroughly and completely distribute the dopant into the Fe 2 O 3 . As noted, if it is desired to prepare an n-type electrode, the desired amount of SiO 2 is mixed with the Fe 2 O 3 . If a p-type electrode is to be produced, the desired amount of MgO is mixed with the Fe 2 O 3 .
Once thoroughly mixed, the powders are compressed to form tightly adherent pellets, or disks. Pressures in the order of about 7000 kg/cm 2 are sufficient to produce tightly compacted pellets or disks.
The compacted pellets, or disks are then placed in a furnace under air atmosphere, and sintered. In order to produce electrodes with the desired properties, sintering temperatures within the range of 1340° to about 1480° C., are necessary. The compacted pellets or disks, are held at the noted temperatures for a number of hours, preferably in the neighborhood of 15-20 hours in order to fully sinter the powdered components.
After the desired sintering time has elapsed, the electrodes are rapidly cooled to room temperature, by removing them from the sintering furnace and immediately placing them on metal sheets in the open air. The metal sheets, e.g., aluminum or stainless steel, act as heat sinks to rapidly draw the heat from the electrode compacts. At the same time air is permitted to freely circulate over the electrode surfaces to add to the rapid cooling.
Alternately, the p-type electrode, i.e., Fe 2 O 3 +MgO can be quickly quenched in water to produce electrodes with the desired resistivity and response to light energy. The n-type electrodes, however, should not be water quenched, since such quenching reduces their ability to generate a current on light illumination.
In any event, after reaching room temperature, the electrodes are ready for use in an electrolytic cell, or they may be stored indefinitely for use at a later time.
Other electrode configurations can be utilized. For instance, a thin film of the doped iron oxide can be affixed to a backing material to make a composite electrode in which the doped iron oxide comprises only the exposed surface area. Other electrode configurations will be apparent to those skilled in the art. Such improved configurations may contribute to increased power efficiency of such cells.
Electrode material prepared according to the above procedures has been studied to elucidate the surface morphology and phase characteristics. X-ray analysis, scanning electron microscopy, and Auger electron spectroscopy, showed the SiO 2 -doped material to be heterogenous with two phases. One phase was the Fe 2 OO 3 matrix doped with Si. The second phase was Fe 2 3 highly enriched with Si. The MgO-doped samples consisted principally of an Mg-doped Fe 2 O 3 matrix.
The resistivity of such electrode material was in the range of 10 3 -10 4 ohms.cm, where the Si dopant ranged from 1-20 atom %. Where the material was doped with Mg, in a range of from 1-10 atom %, the resistivity ranged from 10 3 -10 5 ohms.cm.
EXAMPLE 1
Photoelectrochemical and photochemical experiments were conducted in an apparatus consisting of an electrochemical cell for measurements of current-potential curves and a closed circulation loop for transporting H 2 gas produced from the cell to a gas chromatograph where the amount of hydrogen produced was detected. For standard photoelectrochemical studies the cell consisted of a working electrode, a Pt counter electrode and a Mercuric Oxide Luggin capillary reference electrode. The cell was further fitted with a quartz window for illuminating the electrodes and with provisions for inert gas inlet and outlet. Current-voltage curves obtained in the dark and under illuminations were obtained using a Pine RDE 3 potentiostat enabling the sample to be studied either under potentiostatic or potentiodynamic conditions. All dark and photocurrent figures were obtained under potentiostatic steady state conditions.
Illumination of the cell was provided by a 500 W Tungsten halogen lamp focused with quartz optics and with most of the infra-red radiation absorbed by a 5 cm water cell. A visible pass filter (Corning 3-72) allowed photons with hν≦2.7 eV to illuminate the electrodes. The irradiance was measured with a thermopile detector. The incomimg power at the electrodes was 35 mW on a 1 cm 2 surface area.
A gas chromatograph (Hewlett Packard 5720 A) fitted with a thermal conductivity detector and a molecular sieve 5A column was used to detect H 2 produced in the cell. Calibration of the gas chromatograph was carried out by injecting small but well defined doses of H 2 and O 2 directly into the cell. The detection limit corresponded to a production rate in the cell of 10 16 H 2 molecules/hour. The detection limit for O 2 was 15 times higher. Direct measurements of photoinduced O 2 production was difficult, however, because of high leak rates (of the order of 10 17 O 2 molecules/min) into the cell and loop system. The closed loop contained argon gas to carry H 2 from the cell through a sampling valve to the gas chromatograph. The gas was circulated by means of a mechanical pump. Blank experiments involving only the electrolyte and a sample holder in the cell gave no indication of H 2 produced, either in the dark or under illumination.
To connect the sample to the potentiostat a Ni wire was attached to one side of each sample with Ag epoxy. Silicon rubber sealant was used to insulate the wire and the epoxy from the electrolyte solution. In other experiments p- and n-type iron oxide electrodes were connected by means of a Ni wire and a microammeter, thereby enabling measurement of the photoinduced current between the electrodes in addition to measuring the amount of hydrogen evolved from the p-type iron oxide cathode. These experiments were carried out in the same cell as before but without using the potentiostat.
The n-type and p-type iron oxide electrodes were studied separately and then as the p/n diode assembly. The onset potential for the production of photocurrent was an important parameter considered. If a photoinduced current is to occur between an n-type and a p-type sample without any applied potential, a necessary condition is that the onset potential of the n-type electrode be less (more cathodic) than that of the p-type electrode. An onset potential for phtocurrent production can be defined as the lowest potential where a photocurrent of 0.5 μA/cm 2 is observed.
Table I (middle column) below sets forth the onset potential of Si-doped iron oxides in 0.01 N or 1 N NaOH as a function of the atom fraction of Si.
TABLE 1______________________________________Onset Potential (mV, RHE) for PhotocurrentProduction of Iron OxideWith Different Atomic Fractions of Si Onset Potential Onset Potential After Oxidation in 1 N NaOH or Treatment (O.sub.2 purgingSi/Si + Fe 0.01 N NaOH at 60/80° C.) in(atom %) (mV, RHE) 1 N NaOH (mV, RHE)______________________________________0 725 ± 25 650 ± 501 600 ± 25 500 ± 502 600 ± 25 450 ± 503 625 ± 25 475 ± 505 600 ± 25 450 ± 5010 650 ± 25 575 ± 5020 650 ± 25 600 ± 5050 700 ± 25______________________________________
As shown in the Table, the onset potential dropped from 0.725±0.025 V to 0.600±0.025 V (RHE) upon introduction of 1 atom % Si and remained at that value with increasing Si concentration. Above 20 atom % Si the onset potential rose again. These results hold true in both 0.01 N NaOH and 1 N NaOH, with a tendency for the onset potential to be slightly less in the 1 N NaOH solution.
The onset potential for photocurrent production could be further lowered by oxidizing the n-type iron oxide surface. This was accomplished either by anodic polarization of the sample at potentials above 900 mV (RHE) or by purging the solution with oxygen at temperatures in the range of 60° to 80° C. With both oxidizing treatments a decline in onset potential was observed in the range of 100-200 mV for most of the Si-doped iron oxides studied. Thus, the combination of Si-doping and oxidation of the iron oxide samples decreased the onset potential by 100 mV to 300 mV as compared to undoped n-type iron oxide.
Table 2 below sets forth the onset potentials for photocurrents production of p-type Mg doped ion oxides in 0.01 N NaOH and 0.1 M Na 2 SO 4 . The solutions in which the Mg-doped iron oxides were tested included 0.1 M Na 2 SO 4 , 0.01 N, 1 N and 3 N NaOH, 0.5 M NaCl and distilled water. The photocurrents in the NaOH solutions increased with decreasing pH (as opposed to the behavior of n-type samples which exhibit decreased photocurrent with dilution) but were poor in distilled water.
During prolonged polarization no poisoning of the photoactivity was observed. While polarizing a Mg-doped sample (Mg/Mg+Fe=5 atom %) at 600 mV (RHE) the photocurrent in the 0.01 N NaOH solution increased over an 8 hour period by 50% and in the 0.1 M Na 2 SO 4 solution by 30% in the same time span.
TABLE 2______________________________________Onset Potential (mV, RHE) for Photocurrent Productionof Iron Oxide With Different Atomic Fractions of Mg Onset Potential in Onset Potential inMg/Mg + Fe 0.01 N NaOH 0.1 M Na.sub.2 SO.sub.4(atom %) (mV, RHE) (mV, RHE)______________________________________1 1000 ± 50 850 ± 505 950 ± 50 825 ± 5010 950 ± 50 850 ± 5020 725 ± 50 650 ± 50______________________________________
As will be noted in Table 2, in both solutions the three lower Mg dopant levels give similar onset potentials, while the 20 percent Mg doped sample exhibited 200-300 mV lower onset potentials. In the NaOH or in the Na 2 SO 4 solutions poisoning of the p-type iron oxides occurred after 6-8 hours of exposure when connected with an n-type iron oxide. Oxygen introduced after a sample had been poisoned succeeded in reoxidizing the cathode and regenerating a photocurrent comparable to the original photocurrent before poisoning.
As set forth in Tables 1 and 2 above, the onset potential for photocurrent production of n-type Si-doped iron oxides was less (more cathodic) than that of the best p-type Mg-doped iron oxides. When connecting n-type and p-type iron oxides by a conducting wire over a microammeter, a certain photocurrent would be expected to flow between the n-type and p-type iron oxides.
In a number of experiments, p/n iron oxide diode assemblies were made with n-type iron oxide anodes that contained Si/Si+Fe=2 atom %; while the p-type iron oxide cathodes had Mg dopant levels varied between 1 and 20 atom %. The photoactivity of the p/n assembly in different aqueous solutions was measured either by monitoring the photocurrents, or detecting H 2 in the gas chromatograph. Table 3 below gives measured photocurrents of p/n iron oxide assemblies with different Mg contents. The results are based on 1 hour of exposure in 0.01 N NaOH and in the absence of an external potential. Values of photocurrents were measured when both samples were illuminated, or when either the n-type or the p-type iron oxide was illuminated alone. Illuminating both samples gave photocurrents which in general were higher than the sum of the photocurrents produced when only illuminating either the n-type or the p-type sample. Variation in photocurrents during one hour were typically within ±5%. As seen in Table 3, a dark current was observed which was below 0.5 μA and which decreased with time to less than 0.1 after 10-20 hours of exposure.
TABLE 3______________________________________Measured Photocurrents in p/n Iron Oxide AssembliesAfter One Hour of Exposure in 0.01 N NaOHn-type: Si/Si + Fe = atom %p-type: Mg/Mg + Fe = 1, 5, 10 and 20 atom %Mg/Mg + Fe (atom %) 1 5 10 20______________________________________Photocurrent (μA)both n- and p-type illuminated 5 8 13 3only n-type illuminated 2.5 2.5 3.5 2.5only p-type illuminated 1.5 1.5 4 0.5no illumination <0.5 <0.5 <0.5 <0.5______________________________________
The photoactivity of the p/n diode assemblies was also measured by detecting the H 2 evolution from the p-type cathode. When photoinduced H 2 production rates were measured in addition to photocurrent, an agreement within ±25% was found as shown in Table 4 below.
TABLE 4______________________________________Measured Photocurrents and H.sub.2 Production Ratesin p/n Iron Oxide Assembly After One Hour ofExposure in 0.01 N NaOH and 0.1 M Na.sub.2 SO.sub.4n-type: Si/Si + Fe = 2 atom %p-type: Mg/Mg + Fe = 5 atom % 0.01 N NaOH 0.1 M Na.sub.2 SO.sub.4______________________________________Both samples illuminated 8 ± 1 6 ± 1Photocurrent (μA)H.sub.2 production rate 6 ± 0.5 5 ± 0.5(10.sup.16 molecules/hour)______________________________________
Steady state rates of H 2 evolution in the range of one monolayer (=10 15 H 2 molecules) per minute could be sustained for hours in both 0.01 N NaOH and 0.1 M Na 2 SO 4 in the absence of any external potential.
After about 6-8 hours of exposure in both NaOH and Na 2 SO 4 electrolytes the H 2 production rate and the photocurrent in the p/n iron oxide diode declined. Subsequent separate photoelectrochemical measurements showed that the photoactivity of the p-type iron oxide had declined in proportion, while the photoactivity of the n-type sample remained unchanged. The partly deactivated assembly could be readily regenerated by flowing oxygen through the solution at room temperature for 1-20 minutes. Using this treatment, both the H 2 production and the photocurent returned to their original higher values. | Chemical compounds can be dissociated by contacting the same with a p/n type semi-conductor diode having visible light as its sole source of energy. The diode consists of low cost, readily available materials, specifically polycrystalline iron oxide doped with silicon in the case of the n-type semi-conductor electrode, and polycrystalline iron oxide doped with magnesium in the case of the p-type electrode. So long as the light source has an energy greater than 2.2 electron volts, no added energy source is needed to achieve dissociation. | 8 |
This is a continuation of application Ser. No. 1,670, filed Jan. 8, 1979 now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention:
Fiberoptic endoscope with particular reference to improvements in means for effecting remote articulation of ends of small diameter medical and industrial fiberscopes.
2. Discussion of the Prior Art:
Remote articulation of the distal ends of medical and industrial fiberscopes is commonly provided. This is either articulation in one plane only (two-way) or articulation in all planes (four-way). Two-way devices require two wires leading from the fiberscope tip to its proximal end and prior art four-way devices require four wires, two for each of two mutually perpendicular planes. The structures of U.S. Pat. Nos. 3,913,568 and 3,091,235 are respectively exemplary of two-way and four-way devices.
In small diameter fiberscopes, e.g. bronchoscopes of 5 to 6 mm in overall diameter, the heretofore trade-off of image-conducting and object-illuminating fiber space for manipulating wires, or vice versa, has posed the problem of selection between larger or more intense image conductance and four-way, two-way or no remotely-controlled distal articulation of the fiberscope. For example, the advantage of four-way articulation has required the sacrifice of a number of light-conducting fibers and/or biopsy channeling whose total cross-sectional area corresponds to that of four control wires and their guides.
Accordingly, in the interest of increasing image size and/or illuminating bundle size in universally articulable fiberscopes of restricted overall diametral sizes, it is an object of this invention to accomplish remotely-controlled distal articulation in all planes (4-way) with less than four control wires.
More particularly, it is an object of the invention to accomplish four-way distal articulation of a fiberscope with a three-wire system which affords greater than usual space for fiberscope light-conducting fibers and/or channeling.
Another object is to provide improved distal vertebration in an articulable fiberscope.
Still another object is to overcome the heretofore complexity of fiberscope remote control apparatuses by structural simplification and reduction of component parts.
Other objects and advantages of the invention will become apparent from the following description.
SUMMARY OF THE INVENTION
The foregoing objects and their corollaries are accomplished with three-wire control which provides for fiberscope articulation in all planes (4-way) with space available for light-conducting fibers of biopsy channeling and like in place of the usual fourth wire and wire guide.
Centrally hinged hollow vertebrae, constrained against lateral displacement, comprise the supporting structure for distal articulation with light-conducting fibers and biopsy channeling or the like extended therethrough around the hinging. Three operating wires guided through peripheral portions of the vertebrae at approximately equally circumferentially spaced locations afford control means for articulation of the fiberscope. These simple centrally hinged fiberscope vertebrae avoid the costliness and complexity of previously pinned, socketed or similarly jointed fiberscope vertebrae.
Details of the invention will become more readily apparent from the following description when taken in conjunction with the accompanying drawings.
IN THE DRAWINGS
FIG. 1 is an illustration of a distally vertebrated remotely articulable fiberscope incorporating an embodiment of the present invention;
FIG. 2 is a greatly enlarged cross-sectional view taken approximately along line 2--2 of FIG. 1;
FIG. 3 is a face view of a vertebra of the structure illustrated in FIG. 2 taken along line 3--3 with adjoining and surrounding components of the fiberscope omitted for clarity of illustration; and
FIG. 4 is a cross-sectional view taken along line 4--4 of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Fiberscope 10 of FIG. 1 having probe 12 and head 14 with operating handle 16 is distally universally articulable as illustrated with broken lines 18, i.e. with remote operation at head 14 the distal portion 20 of probe 12 may be flexed in all directions away from the position of full line illustration. This articulation is known in the art as "four-way" since it has heretofore required the use of four operating wires, two for each of two mutually perpendicular planes. With improved vertebration, however, the present invention affords full four-way articulation with three-wire control as follows:
Distal vertebration in portion 20 of probe 12 comprises a series of centrally hinged vertebrae 22 secured against longitudinal and lateral misalignment with wire 24.
Vertebrae 22 are each internally webbed to provide three approximately equally circumferentially spaced channels 26, 27 and 28 through which illuminating and image-conducting fiber bundles 32 and 34 (FIG. 2) and/or biopsy channeling (not shown) may be extended.
In each case of each vertebra, webs 36, 38 and 40 (FIGS. 3 and 4) support double-ended hinge portion 42 through which retaining wire 24 is extended.
Vertebrae 22 are fixed against relative longitudinal displacement by anchoring of opposite ends of wire 24, one in fiberscope tip 44 and the other in retainer 46. Abutting end faces 48 of hinge portions 42 allow universal hinging of vertebrae 22. Hinging is effected by pulling forces applied to the marginal portion of fiberscope tip 44, i.e. by one or more of operating wires 50, 52, 54.
Wires 50, 52, 54 extending from fiberscope head 14 are loosely threaded through retainer 46 and marginal portions of vertebrae 22 and are anchored in tip 44 at approximately 120° circumferential intervals. The anchoring of wires 50, 52, 54 and retaining wire 24 in fiberscope tip 44 may be accomplished by soldering, brazing, swaging or combinations thereof, i.e. by any fastening scheme deemed appropriate to the artisan.
Remote ends of the three operating wires 50, 52, 54 may be manipulated as follows to effect articulation of distal portion 20 of probe 14;
All three wires may be manipulated independently by lever operation or electrically, hydraulically or pneumatically with servo drive. Alternatively, two wires may be activated as suggested above with the third wire spring loaded to return distal portion 20 to its unflexed position. The latter is a presently preferred version of manipulation since it minimizes the degree of operating technique and learning process required of an operator.
Lever operated actuating means applicable to the threewire system of the present invention is illustrated in U.S. Pat. No. 3,091.235.
For reasons of clarity of illustration of vertebrae 22, fiberoptic light-conducting bundles and/or biopsy channeling or other tubing have not been shown in FIGS. 3 and 4. It should be understood, however, that the entire cross-sectional area of each of channels 26, 28 and 30 is available for reception of such light-conducting means and/or channeling. As shown in FIG. 2, for example, light-conducting bundle 32 is extended through one of channels 26, 28 and 30 of the succession of vertebrae 22 and thence through fiberscope tip 44. By such means, objects to be examined with the fiberscope may be illuminated with light from a remote source located in head 14, for example.
Bundle 34 of optical fibers extended through another of channels 26, 28 and 30 of vertebrae 22 is terminated in tip 44 with objective lenses 56 adapted to form images of an object illuminated by bundle 32. In the usual fashion, such images may be transmitted by internal reflection through bundle 34 to a viewing plane in fiberscope head 14 and viewed directly or with the aid of an eyepiece 58.
Remaining space through vertebrae 22, e.g. a third of channels 26, 28 and 30, may be occupied by biopsy channeling or other tubing and/or additional optical fibers. The use of channeling in a fiberscope can be seen in drawings of the structure of U.S. Pat. No. 3,091,235.
Those skilled in the art will readily appreciate that there are various modifications and adaptations of the precise form of the invention here shown which may suit particular requirements and that the foregoing illustrations are not to be interpreted as restrictive of the invention beyond that necessitated by the following claims. | Universal articulation of the end of a medical or industrial fiberscope is accomplished with three-wire control for reducing space requirements in small diameter instruments. | 0 |
FIELD OF THE INVENTION
[0001] The invention relates generally to a method for operating a drivetrain of a motor vehicle, and to a drivetrain module of a motor vehicle of said type.
BACKGROUND
[0002] The drivetrain of a conventional motor vehicle with an internal combustion engine as the sole drive source normally has a launch element in the power flow between drive source and drive wheels for the purposes of permitting a launch process of the motor vehicle. Examples of such a launch element are hydrodynamic torque converters or friction clutches. The drivetrain of a motor vehicle with an electric motor as the sole drive source generally does not require a launch element because the electric motor can accelerate the vehicle from a standstill.
[0003] The drivetrain of a parallel hybrid vehicle normally requires a launch element if it is also sought for a launch process to be performed by the internal combustion engine alone. For the electric launching of a motor vehicle with parallel hybrid drivetrain, numerous variants are known in the prior art. The applicant's patent application publication DE 10 2006 018 058 A1 discloses a variety of launch processes for a motor vehicle with parallel hybrid drivetrain. FIG. 4 shows profiles with respect to time in the case of a purely electrically driven launch process with a slipping converter lock-up clutch, and FIG. 5 illustrates such profiles with a closed converter lock-up clutch. A method for providing the pressure for closing the converter lock-up clutch in the case of launch behavior as per FIG. 5 is not disclosed here.
[0004] The patent application publication DE 101 62 973 A1 discloses a hybrid drivetrain of said type, with a mechanical oil pump and an electric oil pump. The mechanical oil pump can be driven by the motor-generator of the drivetrain. The electric oil pump is driven by a dedicated electric motor. The electric oil pump is actuated in a manner dependent on different operating states of the drivetrain in order to supply oil pressure to a hydraulic control device of the transmission.
SUMMARY OF THE INVENTION
[0005] A launch process with a closed or locked-up launch element is particularly energy-efficient, because no energy that is imparted by the drive source is lost as a result of slippage between the drive source and drive wheels. It is now an example object of the invention to specify a method for operating a drivetrain, by which method fast operational readiness of the drivetrain is ensured with simultaneously low energy outlay.
[0006] The method is suitable for the operation of a motor vehicle drivetrain which includes at least one drive source in the form of an electric motor, a transmission for providing different transmission ratios between a drive shaft and an output shaft of the transmission, a launch element in the power flow between the drive source and the output shaft, and a pump, which can be electrically driven independently of the drive source by a separate electrical pump drive and which serves for the hydraulic supply of pressure to the transmission. The electric motor may serve either as the sole drive source in the drivetrain, or may operate together with an internal combustion engine in a hybrid drivetrain. The launch element may be arranged outside or within the transmission. The pump may be structurally integrated into the transmission.
[0007] According to example aspects of the invention, when the motor vehicle is at a standstill and in the presence of a demand for the provision of a drive torque of the motor vehicle, the power supplied to the pump drive is increased. In this way, it is possible to briefly make available an oil pressure sufficient for performing fast charging of that pressure chamber whose pressurization effects the complete closure or lock-up of the launch element. If a gear ratio between drive shaft and output shaft is formed by non-positively locking shift elements (e.g., friction shift elements) with hydraulic actuation, it is also possible to perform fast charging of said elements. Following this, a launch process, driven by the electric motor, of the motor vehicle is performed with a closed or locked-up launch element. The power supplied to the pump drive is in this case reduced after the fast charging has been performed, whereby the energy consumption of the pump is also reduced. This improves the energy efficiency of the drivetrain.
[0008] It is preferably provided that the power supplied to the pump drive is, after the fast charging has been performed, reduced to a value which is dependent on the setpoint drive torque. The setpoint drive torque may for example correspond to an accelerator pedal position. In this way, the energy consumption of the pump can be reduced to a minimum in that, in the presence of a low setpoint drive torque, a correspondingly low setpoint pressure of the pump is output. The power supplied to the pump drive is in this case preferably just high enough that slippage of the launch element or of the shift elements of the transmission can still just be prevented in the case of the present drive torque.
[0009] In a preferred refinement, the reduction of the power supplied to the pump drive is performed in continuous or stepped fashion. In other words, an abrupt reduction of the power supplied to the pump drive is intentionally avoided in order to at any rate prevent a sudden occurrence of slippage of the launch element or of the shift elements of the transmission. In this way, high operational reliability and a high level of driving comfort are ensured.
[0010] It is preferably the case that, after the fast charging has been performed, the power supplied to the pump drive is reduced only after a predetermined rotational speed value of the electric motor has been reached or overshot. This is relevant in particular if the pump can also be driven by the drive source, or if a second pump which is driven by the drive source is available for the hydraulic supply of pressure to the transmission. As soon as the supply of pressure to the launch element, or the locking-up thereof, and to the shift elements of the transmission is performed by operation of the drive source, the separate pump drive can be deactivated.
[0011] The predetermined rotational speed value for the reduction of the power supplied to the pump drive may be temperature-dependent, for example dependent on the ambient temperature or on the temperature of the transmission oil. This is because, in the case of cold transmission oil, the oil is more viscous, whereby the gap losses are lower than in the case of warm transmission oil. It is thus possible, in the presence of cold transmission oil, for a high pressure to be built up even at low rotational speeds.
[0012] In addition to the method according to example aspects of the invention, a drivetrain module of a motor vehicle is also specified. The drivetrain module includes at least one drive source in the form of an electric motor, an interface to an internal combustion engine of the motor vehicle, a control unit, a transmission for providing different transmission ratios between a drive shaft and an output shaft of the transmission, a launch element which can be hydraulically actuated or locked up and which is situated in the power flow between the drive source and the output shaft, and a pump, which can be driven independently of the drive source by means of a separate electric pump drive and which serves for the hydraulic supply of pressure to the transmission. Here, the control unit is set up for controlling the method as described above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Exemplary embodiments of the invention will be described in detail below on the basis of the appended figures. Identical and similar components are in this case denoted by the same reference designations. In the figures:
[0014] FIG. 1 shows a parallel hybrid drivetrain with a hydrodynamic torque converter as launch element;
[0015] FIG. 2 shows a parallel hybrid drivetrain with a launch element integrated in the transmission; and
[0016] FIG. 3 and FIG. 4 show profiles of different variables of the drivetrain with respect to time.
DETAILED DESCRIPTION
[0017] Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.
[0018] FIG. 1 schematically shows a drivetrain, in the form of a parallel hybrid drivetrain, of a motor vehicle. The drivetrain has an internal combustion engine 9 and a drive source 1 in the form of an electric motor, wherein a separating clutch 10 is connected between the internal combustion engine 9 and the electric motor 1 . Furthermore, the drivetrain of FIG. 1 includes a transmission 2 with a drive shaft 21 and an output shaft 22 , and also a launch element 3 , wherein the launch element 3 is positioned between the electric motor 1 and the drive shaft 21 . The launch element 3 is a hydrodynamic torque converter which can be locked up by a lock-up clutch 3 B connected in parallel. The output shaft 22 is connected in terms of drive to drive wheels of the motor vehicle.
[0019] If it is the intention that a motor vehicle equipped with the drivetrain of FIG. 1 be launched using the electric motor 1 alone, this may be performed with a slipping converter or with a converter locked up by the closed lock-up clutch 3 B. In the case of a launch process with a slipping converter, the electric motor 1 may run at any desired rotational speed, while the output shaft 22 is stationary, for example as a result of actuation of a service brake of the motor vehicle. In the case of a launch process with a closed lock-up clutch 3 B, the rotational speeds of electric motor 1 and output shaft 22 are coupled by the transmission ratio selected in the transmission 2 .
[0020] For the supply of oil pressure to the transmission 2 , a pump 26 is provided which is driven by the drive shaft 21 by a chain drive. However, if the drive shaft 21 is stationary, the pump 26 cannot provide an oil pressure. For this purpose, a pump 24 is provided which can be driven by a separate electric pump drive 25 . This is to be regarded merely as an example. As an alternative to this example embodiment, it would be possible for the pump 26 to be equipped with a dedicated electric drive by which the pump 26 can be driven independently of the drive shaft 21 . To avoid a situation in which said dedicated electric drive drives the drive shaft 21 , it is possible for a freewheel or a switching element to be provided in the operative connection between drive shaft 21 and pump 26 .
[0021] FIG. 2 schematically shows a drivetrain, in the form of a parallel hybrid drivetrain, of a motor vehicle, wherein the launch element 3 is now integrated into the transmission 2 . The launch element 3 may for example be one of the shift elements which contributes to the formation of the transmission ratios of the transmission 2 . The electric motor 1 is fixedly connected to the drive shaft 21 . The output shaft 22 is connected in terms of drive to drive wheels of the motor vehicle. The supply of oil pressure to the transmission 2 corresponds to the embodiment as per FIG. 1 , for which reason reference is made to the statements relating to FIG. 1 .
[0022] If it is the intention that a motor vehicle equipped with the drivetrain of FIG. 2 be launched using the electric motor 1 alone, this may be performed with a slipping launch element 3 or with a closed launch element 3 . In the case of a launch process with a slipping launch element 3 , the electric motor 1 may run at any desired rotational speed, while the output shaft 22 is stationary, for example as a result of actuation of a service brake of the motor vehicle. In the case of a launch process with a closed launch element 3 , the rotational speeds of electric motor 1 and drive-output shaft 22 are coupled by the transmission ratio selected in the transmission 2 .
[0023] When purely electric driving is performed with the drivetrain as per FIG. 1 or FIG. 2 , the internal combustion engine 9 is typically deactivated, and the separating clutch 10 connected between the internal combustion engine 9 and the electric motor 1 fully opened. By contrast, during hybrid operation, in which both the internal combustion engine 9 and the electric motor 1 are running and provide drive torque, the separating clutch 10 positioned between the internal combustion engine 9 and the electric motor 1 is closed.
[0024] The operation of the internal combustion engine 9 is controlled and/or regulated by an engine controller, and the operation of the transmission 2 is controlled and/or regulated by a transmission controller. For the control and/or regulation of the operation of the electric motor 1 , a hybrid controller is typically provided. The launch element 3 , or the lock-up clutch 3 B, is controlled and/or regulated by a launch element controller.
[0025] Typically, the launch element controller and the transmission controller are implemented in a common control device, specifically in a transmission control device. The hybrid controller may also be a constituent part of the transmission control device. The engine controller is typically a constituent part of a separate control device, specifically of an engine control device. The engine control device and transmission control device exchange data with one another.
[0026] FIG. 3 shows the profile of different variables of the drivetrain with respect to time, including a selection A of the launch process, a rotational speed 1 n of the electric motor 1 , a pressure 3 p for the closure or locking-up of the launch element 3 , a torque 1 t of the electric motor 1 , and the power 25 p supplied to the pump drive 25 . The selection A of the launch process can assume two different values, wherein the value one signifies a launch process with a closed or locked-up launch element 3 , and the value zero signifies a launch process with a slipping launch element 3 . The power 25 p supplied to the pump drive 25 may for example be an electrical current in the case of a constant supply voltage.
[0027] The illustrated exemplary profile shows a launch process with a closed or locked-up launch element 3 . Before the commencement of the launch process, a launch process with a closed or locked-up launch element 3 is selected, whereby the parameter A assumes the value one. Electrical power is thereupon supplied to the pump drive 25 , such that the rotational speed thereof increases. The pump 24 now provides oil pressure, such that the launch element 3 , or the lock-up clutch 3 B thereof, can be closed. The pressure 3 p is initially raised to a first level for the purposes of charging the oil chamber in order to close or lock up the launch element 3 . After charging has been performed, the power 25 p is reduced in continuous fashion to a residual level. This may take place for example after a predefined time has elapsed since the commencement of the charging. After the fast charging has been performed, the pressure 3 p is reduced to a setpoint value 3 po . The setpoint value 3 po is just high enough that, upon the commencement of the launch process, the launch element 3 , or the lock-up clutch thereof, reliably transmits the drive torque. At a later point in time, torque 1 t and rotational speed 1 n increase. Here, a gear ratio is engaged in the transmission 2 , whereby launching of the motor vehicle occurs.
[0028] FIG. 4 likewise shows the profile with respect to time of the variables illustrated in FIG. 3 in the case of a launch process with a closed or locked-up launch element 3 . By contrast to the sequence illustrated in FIG. 3 , the power 25 p is, after the fast charging of the launch element 3 or of the lock-up clutch 3 B thereof has been performed, reduced only after a rotational speed value 1 nt of the electric motor 1 has been reached. Here, the reduction is performed stepwise. The rotational speed value 1 nt may be temperature-dependent, wherein the value 1 nt becomes lower with falling temperature. The oil temperature of the transmission 2 , which is detected by a suitable sensor, may be used as reference temperature.
[0029] Modifications and variations can be made to the embodiments illustrated or described herein without departing from the scope and spirit of the invention as set forth in the appended claims.
REFERENCE DESIGNATIONS
[0000]
1 Drive source
1 t Torque of the drive source
1 n Rotational speed of the drive source
1 nt Rotational speed value
2 Transmission
21 Drive shaft
22 Output shaft
24 Pump
25 Pump drive
25 p Power of the pump drive
26 Pump
3 Launch element
3 p Pressure
3 po Setpoint value
3 B Lock-up clutch
9 Internal combustion engine
10 Separating clutch
A Selection | A method for operating a drivetrain of a motor vehicle, includes, when the motor vehicle is at a standstill and upon demand for a drive torque of the motor vehicle, increasing power ( 25 p ) supplied to a separate electric pump drive ( 25 ) such that a pressure chamber whose pressurization effects a complete closure or lock-up of a launch element ( 3 ) is fast charged with hydraulic pressure from a pump ( 24 ). The method also includes performing a launch process of the motor vehicle with the drive source ( 1 ) and with a closed or locked-up launch element ( 3 ) and reducing the power ( 25 p ) supplied to the separate electric pump drive ( 25 ) after fast charging the pressure chamber. A related drive train module is also provided. | 5 |
FIELD OF THE INVENTION
This invention relates to nanostructures and methods for their fabrication.
BACKGROUND OF THE INVENTION
The discovery of visible photoluminescence (PL) and electroluminescence (EL) from porous silicon has stimulated significant interest in this material and other nanoporous materials. Efficient visible luminescence may be achieved in porous semiconductor layers (e.g. silicon, germanium, silicon carbide, etc.), which has significant economic potential in optoelectronic devices (such as efficient visible emitters, solar cells, photodetectors, photonic band-gap crystals, displays, etc.), in gas and chemical sensors, and as sacrificial layers to realize 3-D patterns with high aspect ratio on bulk semiconductors.
Luminescent porous materials are currently made by a number of methods, including electrochemical anodization, chemical stain etching, hydrothermal etching and spark erosion techniques. In addition, lasers, ion beams and electron beams have also been used to modify the surface properties of various materials such as semiconductor materials.
Although porous materials can be produced by electrochemical anodization and spark erosion techniques, control of such processes is complicated. Using these techniques, it is also very difficult to make nanoporous materials from non-conductive substrates. A good electrical contact must first be formed and then it must be protected during the entire electrochemical etching process. When an electric current through a substrate is used, it is almost impossible to define areas of preferential etching, which makes it difficult for large scale integration (LSI).
When applied to silicon, anodic etching is limited to certain types of doped silicon. The process is difficult to control, particularly for n-type structures, and is not compatible with standard silicon fabrication technology. The formation of patterns is restricted by the application of current to the entire substrate. It is difficult to selectively form a high resolution pattern on the surface of the substrate.
Chemical stain etching is more suitable for massive industrial productions, but, when it is used alone the depth of the etching is shallower than electrochemical anodization. Also, the wetting period is relatively long for chemical stain etching alone, rendering the morphology of the resulting porous material rough and irregular. When used alone, chemical stain etching is usually slow (characterized by an induction period), irreproducible, unreliable in producing light-emitting porous materials, and is mainly used for making very thin layers.
There still remains a need in the art for simple and effective processes for producing luminescent porous materials.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a process for fabricating a luminescent porous material which comprises sequential application, first of laser radiation and then of chemical stain etching to a suitable substrate. Thus, there is provided a process for fabricating a luminescent porous material, the process comprising: providing a substrate suitable for fabricating a luminescent porous material; exposing the substrate to laser radiation in a predetermined pattern; subsequently followed by, exposing the irradiated substrate to a chemical stain etchant to form the luminescent porous material.
There is also provided a luminescent porous material having a luminescence maximum at an energy greater than about 2100 meV.
Pre-treatment of the substrate by laser radiation in a predetermined pattern generally produces a pattern of defects in the substrate, particularly on the surface of the substrate. Defects may include, for example, pits in the substrate, disorders in a crystal lattice of the substrate, etc. Some luminescence may be produced by the laser pre-treatment step, but the luminescence intensity from laser irradiation alone is generally too low for practical applications. The defects caused by laser irradiation serve as nucleation sites and are thus more susceptible to chemical stain etching than the non-irradiated areas of the substrate. The subsequent chemical stain etching step is thus enhanced for those portions of the substrate exposed to the laser radiation, thereby producing bigger and deeper pores and an increase in luminescence intensity in the laser irradiated portions of the substrate. The subsequent chemical stain etching of the substrate thereby produces a pattern of luminescent pores which follows the initial pattern of defects produced by the laser irradiation step.
It is known to use lasers in various micro-machining processes. Such micro-machining processes are designed to remove material from a substrate to produce products that are not luminescent. In contrast, the laser pre-treatment step of the present process minimizes the removal of substrate material while producing defects in the structure of the substrate in order to produce highly luminescent materials upon subsequent chemical stain etching.
Laser etching and chemical stain etching have been traditionally considered as different technologies, consequently, one skilled in the art would not generally consider combining the two technologies. The sequential application of laser radiation followed by chemical stain etching to a substrate may provide any of a number of advantages over existing processes for the fabrication of luminescent porous nanostructures. The process of the present invention may be faster, simpler, more direct and/or less expensive than existing processes. It may also improve accuracy of and/or control over pore size, size distribution, overall pattern formation and/or pattern transfer thereby producing more consistent materials. Better morphology of the luminescent porous material and better reproducibility of pattern formation may be achieved. Wetting time for the chemical stain etching step may be reduced.
Use of a laser beam as opposed to an electron or ion beam has advantageously been found to improve control over defect formation, including control over individual defects, process mechanisms and overall pattern formation, especially when the laser beam is used in conjunction with a subsequent chemical stain etching step. Such control may be obtained, for example, through choice of wavelength, choice of pulse parameters and control of laser articulation. For instance, use of laser irradiation permits structuring of the illumination pattern on the substrate resulting in better control over lateral microstructure of the porous material. Improved control over defect formation gives rise to improved luminescent materials and greater flexibility in the production of luminescent materials for specific applications.
A suitable substrate is any material which will become a luminescent porous material when the substrate is first exposed to laser radiation and then exposed to a chemical stain etchant. The substrate may exist in any solid state form. For example, crystalline, polycrystalline or amorphous forms, or even a substrate existing in a combination of forms, may be used provided the steps of laser irradiation followed by chemical stain etching produce a luminescent porous material.
The process is of particular use for semiconductor substrates. Many kinds of semiconductor substrates are known to those skilled in the art and are commercially available, for example, from Sumitomo Mitsubishi Silicon Corporation of Japan and University Wafers of the United States. Some illustrative examples are, among others, substrates which comprise silicon (Si), germanium (Ge), silicon carbide (SiC), gallium arsenide (GaAs), indium phosphide (InP), gallium indium phosphide (GaInP), indium gallium arsenide (InGaAs), indium gallium arsenic phosphide (InGaAsP), aluminum gallium arsenide (AlGaAs), and layered substrates such as Ge on Si, In/As on Ga/As and Ge/Si on Si, for example. Semiconductor substrates may be doped (e.g. p-type or n-type) or undoped.
The choice of chemical stain etchant is wide, provided the etchant is suitable for etching the desired substrate to produce a luminescent material in combination with laser pre-treatment. One skilled in the art will have little difficulty choosing an appropriate chemical etchant for a given substrate.
Chemical etchants typically, but not always, comprise an aqueous solution of an oxidizing agent and an anion which is capable of forming water-soluble complexes with the substrate. Suitable oxidizing agents include, but are not limited to, nitric acid, nitrates (e.g. lithium nitrate, sodium nitrate, potassium nitrate, barium nitrate, ammonium nitrate, etc.), nitrite (e.g. lithium nitrite, sodium nitrite, potassium nitrite, barium nitrite, ammonium nitrite, etc.), peroxides (e.g. hydrogen peroxide), permanganates (e.g. sodium permanganate, potassium permanganate, etc.), and persulfates (e.g. sodium persulfate, potassium persulfate, etc.), among others. Suitable anions include, but are not limited to fluoride, chloride and bromide, among others. The anion may be introduced in the form of an acid (e.g. HF, HCl, HBr, etc.) or in the form of a salt (e.g. LiF, NaF, KF, LiCl, NaCl, KCl, LiBr, NaBr, KBr, etc.). Etch rates are sometimes pH dependant so the addition of an inorganic or organic acid, such as sulphuric acid, phosphoric acid, acetic acid, etc., may be advantageous. Certain acids may also act as oxidizers.
In one embodiment, the chemical etchant may be a mixture of HF:HNO 3 :H 2 O. Such an etchant finds particular applicability to silicon-based or germanium-based substrates. Other substances, such as ethanol, acetic acid, bromide, etc., may also be used in this etching solution. The addition of bromide is particularly advantageous when the etchant is intended for a germanium-based substrate. The concentrations of each component may vary. A suitable range (by volume) is typically from 1-4 parts HF: 1-5 parts HNO 3 :4-10 parts H 2 O. An additional 1-4 parts of other substances may be included. Some examples are 1:3:5 (HF:HNO 3 :H 2 O), 1:5:10 (HF:HNO 3 :H 2 O), and 1:2:1:4 (HF(49%):HNO 3 (70.4%):CH 3 COOH:H 2 O(additional)).
In another embodiment, the chemical etchant may be an aqueous mixture of permanganate and HF. This etchant is particularly useful for silicon-based or germanium-based substrates. The ratio of etchant components may vary. When potassium permanganate and a 47% HF solution are used, one suitable ratio of permanganate to HF solution is 3:97 by weight.
In another embodiment, the chemical etchant may be a mixture of HCl, acetic acid and water. This etchant is particularly useful for GaAs-based or GaInP-based substrates. The ratio of etchant components may vary. One suitable ratio is 1:10:3.5 (HCl:CH 3 COOH:H 2 O), among others.
In another embodiment, mixtures of water and peroxide with acids such as H 2 SO 4 , HF and HBr are particularly suited for etching GaAs-based substrates. Ratios of etchant components may vary, but typical examples include 8:1:1 (H 2 SO 4 :H 2 O 2 :H 2 O), 10:1:150 (HBr:H 2 O 2 :H 2 O) and 1:8.5:50 (HF:H 2 O 2 :H 2 O), among others.
Other specific etching solutions are known to one skilled in the art and many etching solutions useful for one substrate may also be useful for other substrates.
Substrates may be chemical stain etched for any desired length of time. Typical etch times range from 1 to 180 minutes, more particularly 1 to 60 minutes. The etch time will depend on the size and depth of the pores and on other structural characteristics desired for a particular application. A longer etch time increases the size and depth of the pits formed in the substrate. However, it is generally an advantage of the present process over prior art processes that shorter etch times may be used to obtain similar pit sizes. Chemical stain etching may be performed at any suitable temperature. The temperature at which etching occurs may influence the properties of the luminescent porous material. Typically, etching is performed at or around room temperature. If desired, the substrate may be stirred in the chemical stain etchant using any convenient technique, for example, by using a mixer or by using ultrasound.
Both before and after the chemical stain etching step, substrates may be cleaned and dried to optimize the properties of the resulting porous luminescent material. Typically, cleaning may be done in a suitable organic solvent, such as acetone, ethanol, etc., followed by rinsing with deionized water (or vice versa) and then dried with an inert gas such as nitrogen, argon, etc. Combinations of different types of surface cleaning, etching and post-treatment conditions can give porous layers with various pore diameters.
Any laser may be used to pre-treat the substrate to form the initial pattern of defects in the substrate. Some examples of various types of lasers which may be employed in the invention are Nd:YAG lasers, InGaAsP/InP DFB lasers, GaAs/GaInP lasers, CO 2 lasers, diode pump solid state lasers, femtosecond (FS) lasers and picosecond (PS) lasers. The fundamental or higher harmonics of the laser may all be suitable for use in the process. For example, the fundamental wavelength of the Nd:YAG laser is 1064 nm with the second harmonic wavelength at 532 nm and the third harmonic wavelength at 355 nm. A variety of laser pulse widths may also be used, with pulse widths on the order of 1 millisecond to 1 femtosecond being particularly suitable.
Fabrication of various feature types in a substrate may depend on a balance of various laser process parameters. The choice of laser, laser characteristics and laser processing parameters may also depend somewhat on the type of substrate used. For example, by controlling the combination of pulse width and energy of the laser, different structures and different luminescent properties may be fabricated into a substrate. In general, the variations are virtually unlimited and it is within the ability of one skilled in the art to determine the optimal parameters for fabricating the specific desired features on a case-by-case basis.
Without being held to any specific mechanism of action, it is thought that surface modification of a substrate may be due to rapid heating, melting, resolidification and recrystallization of the substrate by the laser beam. It is further thought that the superheated melt activates internal gettering centres in the substrate, which are more susceptible to subsequent chemical stain etching. In order to optimize the process, control of laser power density is desirable. Very high laser power densities may cause evaporation of the substrate before melting. Therefore, it is desirable to set the laser power density so that the surface temperature of the region of the substrate exposed to laser radiation first reaches the melting point of the substrate and initiates the melting process. The temperature of the melt can then be allowed to rise above the melting temperature but below the boiling temperature to permit the formation of a super-heated melt, resulting in a solid-liquid interface extending into the substrate. It is thought that the build up of high temperature gradients in the region of laser interaction favours the diffusion of impurities in the substrate into the laser-treated region, thus contributing to the activation of internal gettering centres. Since surface morphology appears to be sensitive to laser process parameters, optimization of laser parameters is desirable for obtaining the specific effects for the intended purpose. Such parameters are optimized on a case by case basis depending on the effects desired.
The use of nanosized filters as masks advantageously improves accuracy and control of the laser pre-treatment step providing a more orderly and precise arrangement of defects produced in the substrate by laser irradiation. Use of masks with nano-dimensional feature sizes further facilitates the preparation of luminescent nanoporous materials. In the prior art, obtaining nanosized features on a substrate using standard photoresist masks has been very difficult. It has now been found that the use of nanosized filters in conjunction with the laser pre-treatment step of the present invention enhances the ability to obtain nanosized features on a substrate following the subsequent chemical stain etching step. This represents a further step forward in process control for the fabrication of luminescent nanoporous materials for specific utilities.
A variety of nanosize filters (masks) are suitable for use in the process. Nanosize filters may be obtained commercially, for example, from Whatman and Glycol Specialties Inc., or they may be fabricated using nano-machining methods to obtain custom designed filters. Such nano-machining methods include, for example, electrochemical polishing and anodization (EPA), laser nano-machining and electrochemical machining (ECM).
One skilled in the art will recognize suitable nanosize filters. For example, membrane filters, such as anodic alumina formed by electrochemical anodization, alumina sealed into a sandwich-type structure by polymers with nanosize particles, polymeric membrane filters (e.g. mixed cellulose ester membrane, polycarbonate membrane, etc.), membrane filters made from other nanopore materials, filters made from single crystal aluminum with specific orientation, or combinations thereof, are suitable filters for use in the process. In general, nanosize filters may be made from any nanopore material that is thermally and mechanically stable and can withstand incident laser power density with little or no deterioration.
Filters may be designed with different shapes, thickness, patterns (regular or irregular) and/or different materials to impart desired pore characteristics to the substrate. By selecting appropriate shape, density and size of the nanopores on the masking filter and by optimizing the process parameters of laser pre-treatment, it is possible to improve control over the size and exact position of the area to be subsequently chemical stain etched, leading to improved properties of the luminescent porous material produced. In addition, filters may be cleaned with acetone, ethanol and/or deionized water before use to minimize contamination.
Assist gases and/or other chemicals may be used during laser pre-treatment to assist with the initial patterning. Assist gases may be used to provide an inert ambient condition to avoid unwanted reactions and to help minimize evaporation of substrate during laser pre-treatment. Gases such as argon, helium, air and nitrogen may all be used. The exact pressure of the assist gas is generally not critical, but too low of a pressure may result in agglomeration of the substrate material while too high of a pressure may damage the substrate, cause separation of the mask (filter) or cause other structural changes. A pressure of 1-10 psi (e.g. 5 psi) is generally suitable. The specific assist gas and/or other chemicals used may also depend on the nature of the substrate and on the type of laser being used. One skilled in the art can determine the optimal assist gas and pressure by simple experiment.
A wide variety of coatings may be applied to the nanoporous substrate after fabrication of the porous material to improve the properties of the material. For example, metals (e.g. gold, nickel, copper, aluminum, etc.), ceramics and polymers may all be suitable coatings.
Multi-layered nanoporous structures and materials can be produced using the process of the present invention by choosing process parameters, different laser characteristics, different chemical stain etchants, different assist gases or combinations thereof. Several processing steps using different combinations can be done on a single substrate to fabricate a variety of multi-layered structures and materials.
Luminescent porous materials fabricated by a process of the present invention may have a luminescence maximum at an energy greater than about 2100 meV, or at an energy in a range of from about 2100 meV to about 3500 meV. Therefore, it is now possible to fabricate porous materials that luminesce in a region of the electromagnetic spectrum other than the red region. In one embodiment, a luminescent porous material having a luminescence maximum at an energy of from about 2100 meV to about 2400 meV, more particularly at about 2200 meV, may be fabricated. In another embodiment, a luminescent porous material having a luminescence maximum at an energy of from about 2800 meV to about 3200 meV, more particularly at about 2950 meV, may be fabricated.
Luminescent porous materials fabricated by a process of the present invention may be useful in optoelectronic and other semiconductor devices. For example, the luminescent porous material may find application in optoelectronic devices such as efficient visible emitters, solar cells, photodetectors, photonic band-gap crystals, displays, etc., in gas and chemical sensors, and as sacrificial layers to realize 3-D patterns with high aspect ratio on bulk semiconductors. They may be of particular use in biological applications. The luminescent porous material may also be useful in security applications, for instance, in creating identification marks that are invisible under normal conditions but whose luminescence can be detected with luminescence detectors.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be more clearly understood, preferred embodiments thereof will now be described in detail by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a schematic diagram of a laser pre-treatment system using a direct write laser scanning technique with focused beam;
FIG. 2 is a schematic diagram of a laser pre-treatment system using an unfocused beam;
FIGS. 3 a and 3 b are X-ray diffraction (XRD) patterns of silicon wafers before ( FIG. 3 a ) and after ( FIG. 3 b ) laser pre-treatment;
FIGS. 4 a and 4 b are X-ray photoelectron spectra (XPS) of silicon wafers before ( FIG. 4 a ) and after ( FIG. 4 b ) laser pre-treatment;
FIG. 5 is a scanning electron micrograph (SEM) of nano-structured silicon;
FIGS. 6 a and 6 b are atomic force micrographs (AFM) of nano-structured silicon;
FIG. 7 is a scanning electron micrograph (SEM) of nano-structured gallium arsenide (GaAs);
FIG. 8 is a luminescence spectrum, taken at a temperature of 7 Kelvin, of a nano-structured porous silicon sample fabricated by a process of the invention using a 1:3:5 by volume HF:HNO 3 :H 2 O solution as etchant; and,
FIG. 9 is a luminescence spectrum, taken at a temperature of 7 Kelvin, of a nano-structured porous silicon sample fabricated by a process of the invention using a 1:5:10 by volume HF:HNO 3 :H 2 O solution as etchant.
DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 is a schematic diagram of a preferred laser pre-treatment system using a direct write laser scanning technique with focused beam. A substrate or target ( 100 ) is held in place on an x-y motion stage ( 101 ) by a holder ( 102 ) which has a hole in it to permit passage of laser light to the substrate ( 100 ). A spacer ( 103 ) made of metal or glass prevents the holder ( 102 ) from damaging the substrate ( 100 ). A nanosize filter mask ( 104 ) (for example, with pore sizes between 0.02 and 0.1 μm) is placed on top of the holder ( 102 ) and is held to the holder ( 102 ) with vacuum grease ( 105 ). A glue, such as RTV9732, may be used instead of vacuum grease but vacuum grease is preferred as it is more easily pealed off. The thickness of the holder ( 102 ) is set to provide an optimum gap between the filter mask ( 104 ) and the substrate ( 100 ). The gap size is suitably greater than 50 μm, typically up to 1 mm, and is adjusted depending on other system parameters (e.g. laser wavelength, pore size of mask, laser fluence, thickness of filter) in order to minimize diffraction effects. Likewise, the thickness of the spacer ( 103 ) is set to accommodate the thickness of the substrate ( 100 ).
The motion stage ( 101 ) is movable in substantially orthogonal x and y directions in order to control the locations on the substrate which are exposed to laser radiation during the pre-treatment step. The motion stage ( 101 ) is controlled through a motor control ( 106 ) which in turn is controlled from a computer ( 107 ). The computer ( 107 ) also controls the operation of laser ( 108 ). The computer ( 107 ) can co-ordinate movement of the motion stage ( 101 ) with the operation of the laser ( 108 ) in order to achieve the desired patterning effect on the substrate ( 100 ). Laser light ( 109 ) from the laser ( 108 ) is expanded by a beam expander ( 110 ) in TEM00 mode to provide a good quality gaussian beam. The beam is then reflected from a mirror ( 111 ) to an objective and focusing lens ( 112 ) for focusing on the sample ( 100 ) through the filter mask ( 104 ). An assist gas is introduced through tube ( 113 ) into nozzle ( 114 ) to be directed down to the filter mask ( 104 ) and substrate ( 100 ). In addition to assist gas, suction may also be applied to the region around the substrate using an external nozzle. The combination of precisely controlled movement of the motion stage, careful control over laser parameters, presence of the assist gas and use of the filter mask ( 104 ) permits highly precise and detailed pattern development on the substrate ( 100 ).
The laser ( 108 ) is advantageously a Nd:YAG laser. The short-pulsed (30 ns), ultraviolet wavelength (355 nm) radiation from the third harmonics of the Nd:YAG laser serves as an excellent non-contact tool for semiconductor surface modifications and surface treatments. The high photon energy and short duration of the laser pulses can efficiently initiate photochemical and/or photothermal surface reactions leading to high precision micromachining, indelible marking and microstructure modifications. An average laser power ranging from 0.4 W to 1.9 W is preferably used.
FIG. 2 is a schematic diagram of a preferred laser pre-treatment system using an unfocused beam. A substrate or target ( 200 ) is held to the underside of a holder ( 202 ) by a fastener ( 203 ). Any suitable fastener may be used, for example, adhesive tape, clips, etc., although in FIG. 2 , the use of adhesive tape is depicted. The holder ( 202 ) has a hole in it to permit passage of laser light to the substrate. A nanosize filter mask ( 204 ) is placed on the holder ( 202 ) and is held to the holder ( 202 ) with vacuum grease or glue ( 205 ). The thickness of the holder ( 202 ) between the filter mask ( 204 ) and the substrate ( 200 ) is set to provide an optimum gap between the filter mask ( 204 ) and the substrate ( 200 ). The filter mask ( 204 ) provides a predetermined pattern which is transferred to the substrate ( 200 ) upon exposure of the substrate ( 200 ) to laser light that passes through the filter mask ( 204 ).
An optional motion stage (not shown) is movable in substantially orthogonal x and y directions in order to help control the locations on the substrate which are exposed to laser radiation during the pre-treatment step. The optional motion stage may be controlled through a motor control (not shown) which in turn is controlled from a computer ( 207 ). The computer ( 207 ) controls the operation of laser ( 208 ). When a motion stage is used, the computer ( 207 ) can co-ordinate movement of the motion stage with the operation of the laser ( 208 ). Laser light ( 209 ) from the laser ( 208 ) is expanded by a beam expander ( 210 ) and is reflected from a mirror ( 211 ) through an aperture ( 212 ) to make its way to the filter mask ( 204 ) and substrate ( 200 ). The aperture helps provide a clean laser beam and helps control beam size. Since no objective and focusing lens is used, the laser beam is unfocused and wider (on the order of about 10 mm) compared to the system depicted in FIG. 1 . Thus, more laser fluence is generally required to achieve the desired results. An assist gas is introduced through tube ( 213 ) into nozzle ( 214 ) to be directed down to filter mask ( 204 ) and substrate ( 200 ).
Many of the components of the system depicted in FIG. 2 are similar to those in FIG. 1 and have similar specifications as described for FIG. 1 . The main difference between the systems in FIGS. 1 and 2 is the focusing of the laser beam in the system of FIG. 1 . The system of FIG. 1 is therefore particularly useful for fine work such as printing, wires, etc. while the system of FIG. 2 is most useful for industrial scale fabrications.
EXAMPLE 1
Silicon (Si)
Laser Pre-Treatment:
Commercial (University Wafers) p-type boron-doped (100) Si wafers 530 μm thick with resistivities ranging from 20 to 30 Ω-cm were polished and used as substrates. Laser pre-treatment of the wafers was carried out using a Nd:YAG laser as described for FIG. 1 above. The laser irradiation density was controlled so that the energy level at the irradiated area is equal to or greater than the upper limit energy level for annealing in order to maximize grain size of the p-Si obtained. The pulse width of the laser beam was 30 ns and the frequency from 1 Hz to 30 kHz. Laser power ranging from 0.4 W to 1.9 W was used to find the optimized power density. Circular Whatman Anodisc™ 13 nanosized filter masks were used, having a thickness of 60 μm and a diameter of 13 mm. For some samples, the pore size of the filter was 0.02 μm while for the other samples the pore size of the filter was 0.1 μm. Air was used as the assist gas.
Results from X-ray diffraction (XRD) ( FIGS. 3 a and 3 b ) and X-ray photoelectron spectroscopy (XPS) ( FIGS. 4 a and 4 b ) clearly showed that surface modifications of the silicon substrate occurred as a result of laser irradiation. Referring to XPS results depicted in FIGS. 4 a and 4 b , the silicon substrate showed a characteristic calcium (Ca) 2p peak after laser pre-treatment, and the oxygen (O) 1s peak observed was smaller than the oxygen 1s peak of the silicon substrate before laser pre-treatment. The silicon (Si) 2p peak existed as Si and SiO 2 and the amount of SiO 2 was smaller after laser pre-treatment. Ca is very active and may serve as a nucleation centre during subsequent chemical stain etching at the initial stage. It is evident that XPS results indicate that structural changes resulting from the incident laser radiation results in a redistribution of impurities on the Si substrate surface.
Chemical Stain Etching:
A chemical stain etching solution was prepared by mixing 20 mls of Reagent grade HF (48%) with 60 mls of Trace Metal Grade HNO 3 (69-71%) at room temperature to form an acid mixture. Then, a heavily doped p ++ silicon wafer (about 0.5 cm 2 in area with a resistivity ranging from 0.001 to 0.005 Ωcm) was immersed in this solution for five minutes in order to ensure an adequate supply of positively charged ions in the etching solution to catalyze the etching reaction. The acid mixture was then added to 100 ml de-ionized water (5.9 mΩ-cm) with stirring by magnetic stir bar to form the etching solution (HF:HNO 3 :H 2 O in a ratio of 1:3:5 by volume).
Laser pre-treated silicon substrates as prepared above were cleaned in an ethanol bath, rinsed with deionized water and dried with nitrogen gas. The silicon substrates were then completely immersed in the etching solution and stirred. Sample substrates were taken out after 30 minutes. After removal from the etching solution, substrates were rinsed with deionized water and dried with nitrogen gas. The luminescent porous silicon materials so formed were stored in closed bags under nitrogen gas.
FIG. 5 is a scanning electron micrograph (SEM) of the lower surface layer of the nano-structured silicon fabricated in Example 1. FIG. 5 illustrates the size of the structures formed inside the pores after the process is complete. It is evident that nanosize structures have been formed.
FIGS. 6 a and 6 b are atomic force micrographs (AFM) of nano-structured silicon fabricated in Example 1. FIGS. 6 a and 6 b depict the pattern of pits (pores) seen as peaks and valleys in the porous silicon material. The lower layers of the etched silicon are visible inside individual pores. The x and y axes of the micrographs depicted in FIGS. 6 a and 6 b provide a measure of the width of the peaks and valleys, while the grey-scale intensity provides a measure of the peak height (and therefore pore depth) as delineated in the grey-scale chart to the left of the micrograph in FIG. 6 a . It is evident from FIGS. 6 a and 6 b that the diameter of the pits varies and is typically about 20 nm. Measurement on the depth and diameter of the pits is limited by resolution but depths appear to range from about 3 nm to about 40 nm.
EXAMPLE 2
Gallium Arsenide (GaAs)
A process as described in Example 1 was carried out except that a gallium arsenide (GaAs) substrate was used instead of a silicon substrate. FIG. 7 is a scanning electron micrograph (SEM) of the lower surface layer of nano-structured gallium arsenide (GaAs) fabricated in Example 2. FIG. 7 illustrates the structures formed inside the pores after the process is complete. The magnification in FIG. 7 is about five times the magnification used in FIG. 5 . It is evident that nanosize structures have been formed in the GaAs substrate.
EXAMPLE 3
Luminescence
FIG. 8 is a luminescence spectrum, taken at a temperature of 7 Kelvin, of a nano-structured porous silicon sample fabricated in Example 1. FIG. 8 shows that the energy at which the luminescence intensity is maximum is about 2200 meV, which is in the green/yellow region of the electromagnetic spectrum. FIG. 9 is a luminescence spectrum, taken at a temperature of 7 Kelvin, of a nano-structured porous silicon sample fabricated by a method similar to Example 1 except that a chemical stain etchant comprising 1:5:10 by volume HF:HNO 3 :H 2 O was used instead of a chemical stain etchant comprising 1:3:5 by volume HF:HNO 3 :H 2 O, and the substrate was not pre-cleaned with ethanol before chemical stain etching since it has been found that pre-cleaning is not necessary unless the substrate is particularly dirty or oily. The luminescence spectrum in FIG. 9 shows that the energy at which the luminescence intensity is maximum is about 2950 meV, which is closer to the blue region of the electromagnetic spectrum. The apparent double hump in the luminescence spectrum depicted in FIG. 9 is attributed to noise and the maximum was determined as the energy of half width at half height of the peak.
In contrast, the ion beam milling process as described in U.S. Pat. No. 5,421,958 provides porous silicon materials having a luminescence intensity maximum at a wavelength of about 6800 Angstrom (about 1820 meV), which is in the red/infrared region of the electromagnetic spectrum. The chemical stain etchant used in U.S. Pat. No. 5,421,958 comprised 1:5:10 by volume HF:HNO 3 :H 2 O. It is evident, therefore, that laser etching provides unexpectedly different luminescent properties than ion milling.
Luminescent materials that luminesce in the green/yellow region or blue region may be useful in a variety of applications which may not be appropriate for materials that luminesce in the red/infrared region, for example, in various biological applications.
It is evident to one skilled in the art that modifications to and variations of the disclosed invention may be made without departing from the spirit of the invention and that such modifications and variations are encompassed by the scope of the claims appended hereto. | Disclosed is a process for fabricating luminescent porous material, the process comprising pre-treating a substrate (e.g. crystalline silicon) with laser radiation (e.g from a Nd:YAG laser) in a predetermined pattern followed by exposing the irradiated substrate to a chemical stain etchant (e.g. HF:HNO 3 :H 2 O) to produce a luminescent nanoporous material. Luminescent porous material having a luminescence maximum greater than about 2100 meV may be produced by this method. Such nanoporous materials are useful in optoelectronic and other semiconductor devices. | 1 |
BACKGROUND OF THE INVENTION
This invention relates generally to a flat panel display device having a plurality of electron guns for providing electron beams to electron beam guides and particularly to modulator structures for such a display device.
U.S. Pat. No. 4,128,784 to C. H. Anderson entitled "Beam Guide With Beam Injection Means," describes a beam guide for use in a flat panel cathodoluminiescent display device. The display device is composed of an evacuated envelope containing a plurality of internal support walls which divide the envelope into a plurality of parallel channels. Each channel contains a beam guide extending along one wall of the envelope. An electron gun structure emits electrons which are launched into the beam guides as electron beams. The beam guides include a pair of spaced parallel meshes extending along and spaced from the backwall of the envelope. The meshes contain a plurality of aligned apertures with the apertures being arranged in columns extending longitudinally along the paths of the beams. Each longitudinal column of apertures constitutes a separate beam guide. The apertures also are arranged in rows transversely of the guides. One line of the visual display is generated by ejecting the electron beams out of the guide through the apertures in a single row.
Copending Application Ser. No. 87,451 filed Oct. 22, 1979 by W. W. Siekanowicz, et al. entitled "Modulator With Variable Launch Conditions For Multi-Electron Gun Display Devices," now U.S. Pat. No. 4,263,529 a flat panel display including multiple beam channels each of which encloses guide meshes extending along the length of the channels. Each of the channels includes modulation electrodes and cathode means which provide modulated electron beams to the guide meshes. The guide meshes extend between the modulation electrodes, and the electron beams are propagated along the channels in the space between the meshes. A plurality of pairs of launch electrodes are arranged to span the beam guide meshes. The conditions under which electrons are launched into the space between the guide meshes can be selected by the application of various biasing potentials to the pairs of launch electrodes. Accordingly, conditions under which electrons are launched into the propagation space can be selected substantially independently of the conditions required for operation of the cathode and modulation electrodes.
SUMMARY OF THE INVENTION
A flat panel display device includes an evacuated envelope. The envelope encloses beam guides and cathode means which provide electrons to the beam guides. A plurality of electrode pairs is arranged between the cathode and the beam guides. The application of various combinations of biasing potentials to the electrode pairs permits focusing of the electron beams prior to their injection between the beam guides and allows the use of higher potentials to attract electrons from the cathode.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view, partially broken away, of a prior art display device in which the preferred embodiment can be used.
FIG. 2 is a perspective view of a preferred embodiment of the invention.
FIG. 3 is a cross sectional view of the preferred embodiment in FIG. 2.
FIG. 4 shows equipotentials developed with various biasing potentials on the electrode pairs.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows one form of a flat panel display device which incorporates the preferred embodiment. The display device is generally designated as 10 and includes an evacuated envelope 11 having a display section 13 and an electron gun section 14. The envelope 11 includes a rectangular frontwall 16 and a rectangular backwall 17 in spaced parallel relationship with the frontwall 16. The frontwall 16 and the backwall 17 are connected by four sidewalls 18. A display screen 32 is positioned along the frontwall 16 and gives a visual output when impacted by electrons.
A plurality of spaced parallel support vanes 19 are secured between the frontwall 16 and the backwall 17 and extend from the gun section 14 to the opposite sidewall 18. The support vanes 19 provide the desired internal support against external atmospheric pressure and divide the envelope 11 into a plurality of channels 21. Each of the channels 21 encloses a beam guide assembly of the type described in U.S. Pat. No. 4,128,784. The beam guide assemblies include a pair of spaced parallel beam guide meshes 22 and 23 extending transversely across the channels and longitudinally along the channels from the gun section 14 to the opposite sidewall 18. A focus grid 30 is positioned between the guide mesh 22 and the display screen 32. The screen 32 luminesces when impacted by electrons.
FIG. 2 shows the electron gun section 14 in greater detail. The guide meshes 22 and 23 are parallel to the backwall 17 and are separated by a space 24 in which the electrons emitted by the cathode 26 propagate between the two guide meshes. Both of the guide meshes contain a plurality of apertures 27 which are arranged longitudinally in columns and transversely in rows. Positioned on the backwall 17 are a plurality of extraction electrodes 28 which are arranged parallel to the transverse rows of apertures 27. Electrons emitted from the cathode 26 are injected into the space 24 between the guide meshes 22 and 23 and are propagated along the columns of apertures 27 with each of the columns serving as one beam guide. The extraction electrodes 28 serve a dual purpose in that these electrodes are positively biased, for example +350 volts, so that the positive biasing potentials cooperate with a biasing potential placed upon the focus grid 30 to create electrostatic fields. The electrostatic fields penetrate the apertures 27 to focus the electron beams in the vicinity of the center of the space 24 between the guide meshes 22 and 23. The extraction electrodes 28 also serve to extract the electron beams from between the guide meshes. Thus, when the electron beams are to be extracted from between the guide meshes and directed toward the display screen 32, a negative voltage, for example -100 volts, is applied to one of the extraction electrodes 28. This negative voltage repels the electron beams through the apertures 27 of the guide mesh 22. The electron beams then pass through the apertures 31 of the focus electrode 30 and travel to the display screen 32 to form one line of the visual display.
The cathode 26 is arranged between a "G0" pair of electrodes identified as 29a and 29b. Longitudinally arranged between the G0 electrode pair and the guide meshes 22 and 23 is a plurality of electrode pairs G1, G2, G3 and G4. The electrode pairs G0-G4 extend transversely across the channels 21 and the electrodes of each pair are spaced by a distance which is equal to the spacing 24 between the guide meshes 22 and 23. Accordingly, the electrode pairs G0-G4 and the guide meshes 22 and 23 are coplanar and are parallel to the display screen 32.
As best shown in FIG. 3, electrode pairs G1 through G4 are included within electron gun section 14 and thus are positioned outside of the display section 13 (FIG. 1). Accordingly, the transverse row of apertures 27 which is nearest to the electrode pair G4 is the first row of apertures which can contribute to the visual display of the device. For this reason the electrodes G1 through G4 are substantially unaffected by the biasing potential applied to the focusing grid 30 which is positioned between the display screen 32 and the guide meshes in the display section 13.
The utilization of the G1-G4 electrode pairs permits substantial flexibility in the modulation techniques used to inject electrons into the space 24 between the guide meshes 22 and 23 and yields higher electron velocities into the guide at injection. This is desirable because the electrons are exposed to possible mechanical structural variations for shorter time periods, thereby minimizing the deleterious consequences of such defects. One type of modulation which can be used hereinafter is called G1 modulation. When this modulation technique is employed the G0 electrode pair is biased at a fixed negative potential while the G2 electrode pair is biased at a fixed positive potential. Control of electrons emitted by the cathode 26 then is effected by varying the biasing potential applied to the G1 pair of modulation electrodes. With the fixed biasing potentials applied to the electrode pairs G0 and G2 repectively set at -100 and +300 volts the electrostatic lenses between the G0-G1 and G1-G2 electrode pairs change as the biasing potential applied to the G1 modulation electrode pair varies between 0 and -100 volts. As shown in FIG. 4, with a 0 volt potential on the G1 pair, a potential of -100 volts on the G0 pair causes a relatively deep penetration of the resulting field into the G 0 pair as indicated by the exemplary equipotential 32a. The electrostatic lens between the G1-G2 electrodes is relatively strong and there also is penetration of the field between these two pairs, as indicated by the exemplary equipotential 33a in FIG. 4. As the biasing potential applied to the G1 pair of electrodes approaches -100 volts, the equipotentials between the pairs of electrodes change dramatically. The potentials on the G0 and G1 electrode pairs approach equality so that there is very little field penetration into the G 0 pair, this is indicated by equipotential 32b in FIG. 4. When the biasing potential on the G1 pair reaches -100 volts, a field free region exists between the G0 and G1 pairs. However, because of the increased voltage difference between the G1 and G2 electrode pairs there is increased penetration between these electrode pairs as indicated by the exemplary equipotential 33b in FIG. 4. Obviously as the potential on the G1 electrode pair changes from 0 to -100 volts the equipotentials vary between the configurations shown in FIG. 4.
Variations in the potential on the G1 electrode pair cause changes in the trajectory of the electrons emanating from the cathode 26. For this reason, the biasing potential applied to the G3 pair is used to focus the electrons at a position which is substantially midway between the guide meshes 22 and 23. This is accomplished by setting the potential V3 on the G3 pair at a value V3=√V2V4 where V2 and V4 are the biasing potentials applied to the G2 and G4 electrode pairs respectively. The potential V2 is +300 volts as explained hereinabove. The potential on the G4 pair is selected in accordance with the system geometry, and with a spacing in the order of 50 mils this potential typically will be +350 volts. Accordingly, the biasing potential V3 on the G3 electrode pair is determined by the potentials on the G2 and G4 pairs and focuses the electron beam in the vicinity of the center of the space 24 between the guide meshes 22 and 23. The electron beams, therefore, enter the space 24 between the guide meshes focused. This focusing is maintained by the interaction of the positive biasing potentials applied to the guide meshes 22 and 23, the extraction electrodes 28, and the focusing grid 30 on the other side of the guide meshes.
Another type of modulation which can be used with the modulation structure described herein is called G2 modulation. In this type of modulation the G0 and G1 electrode pairs are both fixed at substantially 0 potential. With an examplary spacing between the guide meshes 22 and 23 of 50 mils, a biasing potential of +100 volts on the G2 pair will cause an electron beam current which is adequate for operational purposes to flow. Accordingly, the beam current can be controlled by varying the G2 biasing potential between 0 and +100 volts.
This type of modulation is desirable because the potential on the G2 modulation electrode pair is the only potential in the cathode region and, therefore, changes in the V2 voltage do not alter the trajectories of the electrons emanating from cathode 26. Accordingly, the focusing of the electron beam does not change. However, the velocities of the electrons increase as the V2 potential increases and, therefore, variations in the mechanical structure of the system have less detrimental effect at the higher current levels where improved tolerance is desirable because the increased velocity exposes the electron beams to the variations for a shorter period of time. However, the potential V3 which biases the electrode pair G3 must be changed as V2 is changed to insure that the electron beams remain substantially parallel. This potential focuses the electron beams midway between the G3 electrodes so that the electron beams are injected between the guide meshes 22 and 23 substantially at the center of space 24. The focusing potentials applied to the guide meshes 22 and 23, the extraction electrodes 28 and the focusing grid 30 coact to retain this focusing as the beams propagate the length of the guide meshes.
Irrespective of whether the G1 or G2 modulation technique is utilized a substantial advantage is realized because the maximum emission level of electrons from the cathode 26 can be controlled substantially independently of the potential selected for the guide meshes 22 and 23. Additionally, the initial focusing between the modulation electrodes is independent of the fixed potentials which are applied to the extraction electrodes and the focusing mesh. Accordingly, the potentials which focus the electrons into the space between the guide meshes can be selected substantially independently from those used to periodically focus the beam down the guide or to extract the beam from the guide. Also, the location tolerances of electrodes near the cathode are very good because they are deposited onto high quality surfaces. | A flat panel display device is composed of a display section and an electron gun section which provides electron beams for forming a visual display on the display section. A line cathode within the electron gun section serves as the electron source. A plurality of electrode pairs are voltage biased to establish the conditions under which electrons are ejected from the cathode and also to focus electron beams for propagation along the display section. | 7 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of the U.S. application Ser. No. 885,790 for a Check Valve Hanger Mechanism, filed July 15, 1986, now abandoned. Applicant incorporates said application Ser. No. 885,790 by reference herein, and claims the benefit of said application for all purposes pursuant to 37 C.F.R. 1.78.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to swing-type check valves for use in pipelines and the like. The invention, more particularly, concerns a removable clapper support member from which a check valve clapper may be pivotably suspended. The present invention concerns a check valve clapper hanger which may be easily installed in and removed from a check valve housing and which provides bearing surfaces for the swinging movement of the clapper.
2. Description of the Prior Art
The most common type of check valve is a swing check valve consisting of a clapper pivotably mounted or hinged inside a check valve housing. Various methods of so mounting the clapper inside a check valve housing are known in the art. These methods employ various hinging arrangements.
In conventional swing check valves, the hanger mechanism from which the clapper is suspended is often an integral part of the valve housing. This type of integral structure unfortunately tends to substantially increase the complexity and cost of making the housing. The increased cost and complexity result from the interrupted cuts that are required in order to machine the clapper hanger in the housing.
Integral formation of the clapper hanger in the check valve housing also necessitates that the clapper hanger be made from the same material as the housing. In certain instances, particularly in highly corrosive or caustic environments, it may prove desirable to have a clapper hanger made with a higher quality, more expensive material than that used in the housing. Unfortunately, in integral hanger/housing structures, this requires that the same high quality metal alloys required for the clapper hanger also be used for the entire valve housing.
Other types of conventional check valves have employed removable clapper hangers. These check valves, however, have not met with wide success because they have been unable to retain the check valve clapper in its proper position inside the check valve housing.
Another drawback of conventional check valves employing removable clapper hangers is the complex, multi-step assembly process required to install the clapper in the clapper hanger. This multi-step process is necessitated by the fact that the clapper is suspended from a horizontally mounted cylinder or hinge which is mounted in adjacent holes in the clapper hanger. Such a configuration is shown in U.S. Pat. No. 3,060,961 to Conley and U.S. Pat. No. 2,923,317 to McInerney. Installation of the clapper disclosed in these two patents requires alignment of the holes in the clapper and clapper hanger followed by insertion of the hinge member through these holes. Disassembly of such a clapper valve requires the repetition of these steps in reverse order. The time required to perform this procedure increases the installation and maintenance costs of such valves.
SUMMARY OF THE INVENTION
The present invention provides a means for pivotably suspending a check valve clapper inside a check valve housing by using an easily removable clapper hanger. This clapper hanger is capable of maintaining proper alignment of the clapper during normal operation of the check valve. The removable nature of the hanger makes possible substantial savings in the cost of making the valve. Thus, the cost of making the housing can be reduced by permitting a continuous counterbore to be machined in the valve housing.
Furthermore, the clapper hanger can be made from a different material than that used to make the valve housing. This flexibility is extremely valuable in environments where high quality, expensive alloys are required for the clapper hanger but are not needed for the housing.
The clapper hanger of the invention will normally comprise a disc or plate-like piece containing an opening in its center. In a preferred embodiment, this opening is bulb-shaped.
As used herein, the term "bulb-shaped" refers to a shape similar to a lightbulb, i.e., having a narrow neck section at one end and a wide section with a curved top at the other end. The bulb-shaped arrangement permits quick, one-step installation and removal of the valve clapper in the clapper hanger.
The neck of the bulb-shaped opening, in the plane of the disc, will normally resemble a cross. In the arms of the cross are two recessed U-shaped members or trunnion bearings. These members are open at the top and project from the underside of the disc or plate on each side of the central neck section of the bulb-shaped opening. The two U-shaped members serve as cradle-like bearing surfaces for the trunnions attached to the clapper.
The clapper hanger is designed and sized to be inserted into the valve housing through an opening in the housing. The opening will normally be in the top of the housing and is adapted to be closed by the valve bonnet. The hanger seats on the housing in generally the same position as the hangers in conventional check valves.
The clapper can be dropped into position in the U-shaped arms of the clapper hanger, thus providing for one step assembly and disassembly. The ease of assembly is in vast contrast to the prior art devices, discussed above, which required pin and hole alignment.
In one preferred embodiment of the invention, the outer perimeter of the clapper hanger forms a complete circle. The diameter of the circle is slightly less than the diameter of the opening in the check valve housing in order to permit a loose fit. The check valve housing in this instance contains abutments which engage the outer sides of the U-shaped arms, thus preventing rotation of the clapper hanger within the opening in the housing.
In another preferred embodiment, the outer perimeter of the clapper hanger is shaped like the letter "C". The mouth of the C is radially opposite the neck section of the bulb-shaped opening contained in the clapper hanger. This C-shaped geometry permits the clapper hanger to be slightly larger than the opening in the housing, but capable of sufficient compression to be readily inserted into the housing. The force acting in opposition to this compression maintains the clapper hanger in proper alignment during normal operation of the check valve. Thus, the clapper hanger in this embodiment compression fits into the housing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top view of one embodiment of the clapper hanger installed in a check valve housing.
FIG. 2 is a cross-sectional view of the embodiment of FIG. 1 taken along the lines 2--2 of FIG. 1.
FIGS. 3A and 3B are top views of two other embodiments of the clapper hanger.
FIG. 4 is an isometric, exploded view of a valve housing interior and clapper for use with the clapper hanger embodiment depicted in FIG. 3A.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, the clapper hanger 12 is shown inserted in check valve housing 10 with the valve bonnet 13 (shown in FIG. 2) removed. U-shaped arms 14 are open at the top and project laterally from the underside of clapper hanger 12 on each side of the central neck section 15 of the bulb-shaped opening 17. The recess 19 in the clapper hanger directly above U-shaped arms 14 gives a cross-shaped appearance to the neck section of the bulb-shaped opening. Clapper hanger 12 has a C-shaped outer perimeter 21 with an opening 23 located radially opposite from U-shaped arms 14.
The clapper hanger 12 may be machined or otherwise fabricated such that its diameter is slightly greater than the diameter of the opening 25 in the valve housing 10. In this situation, the clapper hanger 12 is slightly compressed when it is inserted in the valve housing 10. The force acting in opposition to this compression maintains the clapper hanger 12 in proper alignment in the housing 10.
Referring to FIG. 2, the clapper hanger 12 and the clapper 16 are shown installed in valve housing 10. The clapper 16 is rotatably suspended from the U-shaped arms 14 on the underside of the clapper hanger 12. The clapper 16 is shown in phantom form is its fully open position.
Referring next to FIG. 3A, another embodiment of the clapper hanger of the invention is depicted. The clapper hanger 18 in this instance is circular in its outer shape, containing a bulb-shaped opening 27 in its center. The U-shaped arms 14 are mounted on the underside of the clapper hanger 18 in the same manner as depicted in FIG. 2. Since the clapper hanger 18 here is circular, a device such as a peg may be used to keep it in proper position relative to the other parts of the check valve.
Referring now to FIG. 3B, still another embodiment of the invention is depicted. The clapper hanger 26 here is substantially semicircular in its outer shape. The outer perimeter of clapper hanger 26 covers an arc slightly in excess of 180°. U-shaped arms 14 are open at the top and project from the underside of the clapper hanger 26 in the same manner as described for the clapper hanger 12 above.
The clapper hanger 26 may be machined such that its diameter is slightly greater than the diameter of the valve housing 10. In this situation, the clapper hanger 26 may be slightly compressed when it is inserted in the valve housing 10. The resulting force acting in opposition to this compression helps to maintain the clapper hanger 26 in proper alignment in the check valve housing 10 of FIGS. 1 and 2.
Referring to FIG. 4, the structural abutments 20 are shown on the inside of the valve housing 10 located beside the outer face of each U-shaped arm 14. The abutments 20 are laterally spaced such that the U-shaped arms 14 fit between them in very close tolerance This close tolerance inhibits lateral rotation of the clapper hanger 18, thus maintaining proper alignment of the clapper 16 inside the valve housing 10. Clapper hangers 12 and 26 can also be machined such that they will fit loosely in check valve housing 10 in the same manner as described for clapper hanger 18 in FIG. 3A. In these embodiments, the clapper hangers 12 and 26 are installed in a check valve housing with abutments 20 in order to help maintain proper alignment of clapper 16.
The ease of assembly and disassembly of clapper 16 and clapper hanger 18 is also depicted in FIG. 4. The openings at the top of U-shaped arms 14 permit clapper 16 to be dropped into place or lifted up in one step. This provides significant time and cost savings compared to pin and hole alignment type clapper assemblies.
Many modifications and variations may be made in the embodiments described herein and depicted in the accompanying drawings without departing from the concept of the present invention. Accordingly, it is clearly understood that the embodiments described and illustrated herein are illustrative only and are not intended as a limitation upon the scope of the present invention. | The invention disclosed herein relates to a check valve clapper hanger mechanism from which a check valve clapper may be rotatably suspended in a check valve housing. The check valve clapper hanger mechanism is easily removable from the check valve housing and is capable of maintaining proper alignment of the clapper during normal operation of the check valve. | 5 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an apparatus for automatically grinding surface defects in an elongate block of metallic material such as a bloom and a billet, primarily after it is hot-rolled, and more particularly, to an automatic surface defect grinding apparatus capable of automatically carrying out a longitudinal grinding for the defective surface portion of such a bloom or billet which extends in the direction of the longitudinal axis of the bloom or billet and on which a defect marking has been deposited in a defect inspecting step.
2. Description of the Prior Art
A bloom or billet is manufactured by subjecting an ingot to, for example hot-scarfing, rolling the hot-scarfed ingot and finishing it to a predetermined gauge. In course of formation of an ingot, gas holes may be produced in the peripheral surface layer of the ingot. If the gas holes remain in the surface of the ingot even after it has been hot-scarfed, they tend to be extended in rolling and thus mature into defects on the surface of the billet extending in the direction of the longitudinal axis of the billet. Furthermore, such a longitudinally extending defect may be produced on the surface of a billet in rolling due to malfunction of the rolls in rolling stands. Such defects on the surface of a billet may cause cracking in some applications of the billet and thus are extremely harmful.
Heretofore, such defects on the surface of a billet have been removed by detecting the positions of the defects on the surface of the billet, manually or automatically, applying a defect marking of chalk, paint or the like to the surface of the billet at the detected positions, and manually grinding the marked portions of the surface of the billet by means of a grinding wheel in a deseaming step. This conventional method has required too much labor for deseaming.
Thus, it is an object of this invention to provide an automatic surface defect grinding apparatus capable of automatically and efficiently grinding defective portions on an elongate block of metallic material under a completely unattended condition.
SUMMARY OF THE INVENTION
According to the present invention, there is provided an automatic deseaming apparatus for an elongate block of metallic material characterized by a defect marking detector for detecting defect markings which consist of a material containing a fluorescent pigment which has been deposited on defects in the surface of said block, a defect marking position detector for detecting the positions of the defects, a memory for storing the positions of the defect markings which are within the entire area or a predetermined one of segmented areas of the surface of said block, and a grinding controller for controlling reciprocative grinding action in the direction of the longitudinal axis of said block according to the defect marking informations stored in said memory.
This invention will now be described in detail in connection with the preferred embodiment of the present invention by reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 diagrammatically shows a prior art automatic deseaming apparatus for an elongate material;
FIG. 2(A) diagrammatically shows another prior art automatic deseaming apparatus;
FIG. 2(B) diagrammatically shows still another prior art automatic deseaming apparatus;
FIG. 3(A) is a plan view diagrammatically showing the detecting and storing sections of an embodiment of the automatic surface defect grinding apparatus according to this invention applied to a rectangular billet;
FIG. 3(B) is a side view of the system of FIG. 3(A);
FIG. 3(C) is a sectional view taken along the line X -- X' of FIG. 3(A), with an associated controlling circuit being diagrammatically shown;
FIG. 3(D) more specifically shows the defect marking detector of the apparatus of FIGS. 3(A) and (C);
FIG. 4 shows X -- Y coordinates representing the developed surface of a rectangular billet being deseamed;
FIG. 5(A) is a plan view diagrammatically showing the grinding section of an embodiment of the automatic deseaming apparatus according to this invention applied to a rectangular billet;
FIG. 5(B) is a sectional view taken along the line Y -- Y' of FIG. 5(A), with an associated controlling circuit being diagrammatically shown;
FIG. 6(A) is a partial plan view showing contacting lines or grinding lines between a billet being deseamed and a grinding wheel; and
FIG. 6(B) is a sectional view taken along the line Z -- Z' of FIG. 6(A) showing the contacting relationships between the billet and the grinding wheel.
Referring now to FIG. 1, there is shown a prior art automatic deseaming apparatus wherein a defect marking detector 13 is adapted to detect a defect marking 15 which has been deposited on a billet 14 in an inspecting step and then transmit a defect marking signal through a delay circuit 12 to a controller for a grinding wheel 11 which is located at a certain distance from the marking detector 13, to thereby initiate a grinding action for the defective portion of the billet 14 on which the detected marking 15 has been deposited. In this apparatus, if the billet 14 is in the form of a round bar and only one grinding wheel is used, the billet 14 must be screw-driven, as indicated by arrows A and B. This is not efficient since in grinding the long defect on which the defect marking 15 has been deposited and which extends in the direction of the longitudinal axis of the billet 14, the grinding wheel 11 must be stopped from grinding the billet 14 for a waiting time t w from when a leading portion of the defect marking 15 moves away from under the grinding wheel 11 to when the following portion of the defect marking 15 comes under the grinding wheel 11. Generally, to completely remove a defect through only one grinding action, a high grinding pressure will be required. Grinding under such a high grinding pressure tends to result in a rough ground surface. For this reason, it is usual to remove a defect through two or more repetitive grinding actions. However, such a repetitive grinding system limits the rate of screw-driving of a material being ground. For example, in a system wherein grinding action is repeated N times for a given portion of a defect on a billet, the rate of screw-driving of the billet must be set so that the travelling distance per one revolution of the billet may be equal to one-Nth of the width of a grinding wheel used. At such a rate of screw-driving, the waiting time t w will be very long. From this, it will be apparent that for a defect on a billet extending in the direction of the longitudinal axis of the billet longitudinal grinding is more efficient than transverse grinding as in the system of FIG. 1.
In FIG. 2(A), there is shown a prior art automatic deseaming apparatus capable of effecting such a longitudinal grinding wherein a rectangular bar billet 24A being deseamed is moved in the direction of the longitudinal axis of the billet. A plurality of defect marking detectors (or defect detectors) 21 and a plurality of grinding wheels 23 are provided, one for each of widthwise segmented area of the surface of the billet 24A. The grinding wheels 23 are located at certain distances from the corresponding detectors 21. Defect marking signals (or defect signals) from the detectors 21 can be transmitted to the corresponding controllers for the grinding wheels 23 through delay circuit 22. The delay circuits 22 serve to delay a marking or defect signal from the corresponding detectors 21 a period of time which allows the defect marking or defect detected by the corresponding detectors 21 to come under the corresponding grinding wheels 23.
In FIG. 2(B), there is shown a prior art automatic deseaming apparatus similar to the apparatus of FIG. 2(A), but adapted to be applied to a round bar billet 24B rather than a rectangular bar billet.
However, the apparatuses as shown in FIGS. 2(A) and (B) have a disadvantage as will be described hereinafter. In these apparatuses, a number of grinding wheel systems equal to the number of the segmented areas of the surface of a billet being deseamed need to be provided. On the other hand, it is usual that a billet has only a few defects, if any. In deseaming such a billet by means of these apparatuses, only a few of the grinding wheels of the apparatuses actually work to grind a few defects which would exist on the billet, but the remaining grinding wheels will be idle. This is not efficient.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIGS. 3(A) through (D), there is shown the defect detecting section of an embodiment of the automatic deseaming apparatus according to this invention. In this embodiment, a rectangular bar billet 31 being deseamed is placed on a platform car 32. The platform car 32 is movable in the direction of the longitudinal axis of the billet 31 firmly mounted thereon, together with the billet 31. A defect marking detector 33 is provided for the purpose of detecting defect markings on the surface of the billet 31. Although in this embodiment the detector 33 is fixed and the billet 31 is moved with respect to the fixed detector 33, in some cases the billet 31 may be fixed and the detector 33 may be moved with respect to the fixed billet 31.
In a defect inspecting step prior to a deseaming step as carried out by a automatic deseaming apparatus of this invention, a defect marking is applied to a defective portion of the surface of a billet. If the billet consists of a magnetic material, the defect marking may be formed by magnetizing the billet and applying a magnetic powder containing a fluorescent pigment to the defective portion of the surface of the billet. If the billet consists of a non-magnetic material such as austenite stainless steel, the defect marking may be formed by applying a fluorescent chalk to the defective portion of the surface of the billet. Since the fluorescent chalk marking is very handy and applicable to both of billets of magnetic materials and non-magnetic materials, it will be most desirable.
The defect marking detector 33 will now be described in detail with respect to FIG. 3(D).
A defect marking detecting system including the detector 33 is located within a dark-room. A black light 36 emits ultraviolet rays 361 to the surface of the billet to excite the fluorescent chalks of the markings deposited on the defects 31b in the billet surface 31a so as to generate fluorescent radiation. The defect marking detector 33 comprises a fluorescent chalk marking detecting plane 330 consisting of, for example 11 photoreceptor elements y 1 ', y 2 ', y 3 ' . . . y 11 ' spaced in alignment with one another and a lens system 331 for imaging the billet surface 31a onto the detecting plane 330. The lens system 331 may be arranged so that each of the photoreceptor elements y 2 ' through y 11 ' can view the corresponding one of widthwise equally segmented areas of the billet surface 31a, each of which areas has a width of, for example 15 mm. The platform car 32 is provided with billet fixing guides 310 each having a FIG. 311. The FIG. 311 serve to fix the billet 31 to the platform car 32. The surface of a corner edge 31c of the billet 31 may be imaged onto the photoreceptor element y 1 '. Thus, the position of a defect marking on the billet surface along the width of the billet (hereinafter referred as to "lateral position") can be determined according to which of the photoreceptor elements y 1 ', y 2 ', y 3 ' . . . y 11 ' is detecting the defect marking. On the other hand, the position of the defect marking in the direction of the longitudinal axis of the billet (hereinafter referred as to "longitudinal position") can be determined by detecting the distance from the leading edge of the billet to under the defect marking detector. In this embodiment, the longitudinal position of the defect marking is determined by detecting the position of the platform car relative to the defect marking detector. More specifically, the platform car 32 is provided at one side thereof with a plate 37 having binary coding apertures spaced at certain intervals Δx. A platform car position detector 38 is provided for reading out the binary coding apertures of the plate 37, thereby detecting the longitudinal position of the platform car 32.
In operation, as indicated by a phantom line A' in FIG. 3(A), a billet being deseamed is fed onto and secured to the platform car 32. Thereafter, a main controller C 1 as shown in FIG. 3(C) transmits a command signal S 1 to a driver for the platform car 32 to initiate the movement of the platform car 32 and thus the billet 31 to the right side in FIG. 3(A), namely toward the defect marking detector 33. As soon as the leading edge of the billet 31 enters the field of the defect marking detector 33, the detecting operation of the detector 33 may be started. This starting can be achieved in different ways. In this embodiment, as shown in FIG. 3(A), this is effected by means of an arrangement wherein a projector 34 emits infrared rays 341 (see FIG. 3(C)) to a receiver 35. When infrared rays 341 from the projector 34 to the receiver 35 is intercepted by the leading edge of the billet 31, the receiver 35 generates a billet detecting signal U 1 I which in turn is transmitted through an interface C 4 to the main controller C 1 to thereby initiate detecting and storing operations for defect markings. At that time, the main controller C 1 transmits an initiating signal U 4 to an interface C 3 so that whenever the detector 33 detects a defect marking in the billet 31 to generate a defect marking signal U 0 , the signal U 0 can be fed through the interface C 3 to the main controller C 1 . Simultaneously, the platform car position detector 38 transmits platform car position signals or longitudinal position signals U 2 to the main controller C 1 through the interface C 4 . When the main controller C 1 receives a defect marking signal U 0 , it identifies which photoreceptor element has generated the signal U 0 , thereby determining the lateral position of the defect marking corresponding to the signal U 0 . Thus, the position of a defect on a billet can be stored in a memory C 2 as a point (x i , y i ) in X-Y cordinates representing the surface of the billet as shown in FIG. 4. In FIG. 4, Δx indicates the intervals of the binary coding apertures of the plate 37 secured to the platform car 32, and Δy indicates the width of the view of one photoreceptor element of in the detector 33. Practical values of Δx and Δy may be selected dependently on the width and length of the defect marking used. Generally, speaking, it is very difficult to manually apply fine defect markings on the spot. Moreover, even if an automatic marker is used, it is also very difficult to apply fine defect markings since most existing markers are limited in their performance. For these reasons, in practice it is impossible to apply a defect marking smaller than one having a width of 15 mm and a length of 30 mm. In view of this, in this embodiment, Δx is made equal to 50 mm and Δy equal to 15 mm.
When the trailing end of the billet 31 passes through the detector 33, infrared rays 341 from the projector 34 is received by the receiver 35 again. The receiver 35 transmits a billet passing signal U 1 0 to the main controller C 1 through the interface C 4 . Then, the main controller C 1 transmits a car stopping signal S 1 0 through an interface C 5 to the driver M for the platform car to stop the platform car 32 from moving. This completes the operation of detecting the positions of all defects on the billet 31.
Before the billet is subjected to the following defect grinding step, the informations representative of the position of the portions of the defect markings and stored in the memory C 2 may be compiled to provide informations representative of the positions of the whole of each defect marking. The main controller C 1 may determine a sequence of grinding so that the total time necessary for a grinding wheel to successively move to all of the positions of the defect markings may be minimized. This improves the efficiency of grinding.
The grinding operation of this embodiment will now be described in connection with FIGS. 5(A) and (B) and FIGS. 6(A) and (B).
As shown in FIGS. (A) and (B), the defect grinding system comprises a signal grinding wheel 53. Since according to this invention the positions of all defect markings are stored before grinding operation is started, it is possible to use the single grinding wheel for grinding all of the defects on the entire surface of the billet. If the billet is very long, a plurality of grinding wheels may be provided, one for each of lengthwise segmented areas of the entire surface of the billet. Since each grinding wheel can be used for grinding all of the defects within the corresponding one of the segmented areas of the surface of the billet, the number of grinding wheels required in this arrangement is minimized for a given length of billet.
The number of times of grinding may be set by the main controller C 1 , taking into account the degree of deseaming, the material of the billet being deseamed and the type of the grinding wheel used. Since the contacting area between the grinding wheel and the corner edges of the billet being ground is smaller as compared with that between the grinding wheel and the flat surface of the billet, the number of times of grinding in the corner edges of the billet should be set to be smaller than that in the flat surface of the billet.
In the FIGS. 6(A) and 6(B) there are shown contacting lines or grinding lines between the billet and the grinding wheel. In this embodiment, the billet is a rectangular bar having a width of 150 mm. Taking into account the grinding width and depth of the grinding wheel used, five grindings lines a 1 through a 5 for each width of Δy are set to be included, as shown in FIGS. 6(A) and (B). If the width of the billet is smaller, the number of grinding lines may be reduced. Moreover, if the grinding depth should be made larger, the number of grinding lines should also be reduced, since the larger the grinding depth is made, the larger the grinding width becomes.
Grinding operation will now be described in greater detail by way of example in connection with the defect F 0 as shown in FIG. 4.
Assuming that the grinding wheel 53 is positioned as indicated by reference character a 0 in FIG. 6(B) upon completing of the previous grinding cycle. The main controller C 1 transmits a grinding wheel carriage advancing signal S 2 1 through an interface C 6 to operate an oil pressure cylinder 59 to thereby advance the grinding wheel 53 so that the center of the grinding wheel 53 may be aligned with the lateral position of the defect marking F 0 or the grinding line y 1 - a 1 ,1. Whether or not the center of the grinding wheel is aligned with the grinding line y 1 - a 1 ,1 can be detected by monitoring lateral position signals U 3 which the main controller C 1 receives from a grinding wheel carriage position detector 56 (see FIG. 5(A)) through an interface C 7 . In this servo system, as soon as the center of the grinding wheel is aligned with the grinding line y 1 - a 1 ,1, the mail controller C 1 produces a grinding wheel carriage stopping signal S 2 0 to stop the grinding wheel carriage from moving. Subsequently, the main controller C 1 feeds a rightward moving signal S 1 1 to the driver M for the platform car 32 to move the platform car 32 to the right so that the center of the grinding wheel 53 may be aligned with the x 2 portion (see FIG. 4) of the defect marking F 0 which has been closer to the grinding wheel 53. Similarly to the positioning of the grinding wheel with respect to the grinding line y 1 -a 1 ,1 as described above, whether or not the center of the grinding wheel is aligned with the x 2 portion of the defect marking F 0 can be detected by monitoring longitudinal position signals U 2 which the main controller C 1 receives from the platform car position detector 38 through the interface C 4 . As soon as the center of the grinding wheel is aligned with the x 2 portion of the defect marking F 0 , the main controller C 1 outputs a grinding wheel press down signal S 3 1 to press the grinding wheel 53 against the x 2 portion of the defect marking F 0 . Subsequently, the grinding wheel is moved leftwards along the grinding line y 1 -a 1 ,1 to perform grinding until it comes to the x 4 portion of the defect marking F 0 . When the grinding wheel reaches the x 4 portion of the defect marking F 0 , the main controller C 1 receives a longitudinal position signal U 2 from the platform car position detector 38 through the interface C 4 and then generates a rightward moving signal S 1 2 to initiate the opposite directional or rightward movement of the grinding wheel. Then, the grinding wheel is moved rightwards along the grinding line y 1 -a 1 ,1 to perform grinding until it comes to the x 1 portion of the defect marking F 0 . When the grinding wheel reaches the x 1 portion of the defect marking F 0 , the main controller C 1 produces a platform car stopping signal S 1 0 to stop the platform car from moving, if the number of times of grinding has been set to one time only. If the number of times of grinding is set to two or more times, such a grinding cycle should be repeated accordingly. Although the number of times of grinding is represented as the number of times of reciprocation of the grinding wheel in this embodiment, it should be noted that the number of times of grinding may be represented as the number of times of forward movement of the grinding wheel plus the number of times of backward movement of the grinding wheel.
Grinding actions for the grinding lines y 0 - a 2 ,2, y 0 - a 3 ,3, y 0 - a 4 ,4 and y 0 - a 5 ,5 can be successively carried out similarly. Moreover, similar grinding for the other corner edge and flat surface of the billet can be performed similarly. It should be noted that the number of times of grinding in the flat surface of the billet is preferably set to be larger than that in the corner edges of the billet. Similar grinding for the remaining surfaces of the billet can be effected to complete the deseaming for the entire of the billet.
Although in the embodiment described above the billet is in the form of a rectangular bar, this invention may be similarly applied to a round bar billet. In such application, polar coordinate is preferably used to represent segmented areas of the peripheral surface of the round bar billet, in place of Y-coordinate as in the rectangular bar billet.
As described above, according to the principle of this invention, informations or data representative of the positions of all of defect markings which are within the entire surface of a billet being deseamed can be stored in a memory before the grinding operation is actually started. By utilizing the informations stored in the memory, it is possible to continuously carry out longitudinal grinding for all of the defects within the entire surface of the billet without the necessity of screw-driving the billet. Therefore, according to the automatic surface defect grinding apparatus of this invention, defective portions on a billet can be automatically and efficiently ground under a completely unattended condition, thereby resulting in less labor necessary for deseaming.
In the field of detecting defects on a billet, it is known to apply to a defective portion on the billet a defect marking of a chalk having a color different from that of the surface of the billet (for example, if the color of the billet is black, white chalk is used), illuminate the billet and identify the defect marking by detecting the difference between the reflection factors of the billet surface and the color chalk marking by means of, for example a photoconductive semiconductor element which can convert the difference into an electric signal representative of the existence of the defect. However, generally, oil particles tend to be deposited on the surface of the billet and the surface of the billet tends to be rust colored. Furthermore, during conveying of billets from the rolling zone to the inspecting zone and from the inspecting zone to the deseaming zone, the surfaces of the billets tend to be partially ground due to collision or friction between the billets, thereby partially exhibiting a bright color different from the color of the texture of the billet. The known detecting method as described above tends to erroneously detect such oil particles deposited on the billet surface, such rustcolored portions of the billet surface and such bright colored ground portions of the billet surface.
According to this invention, such disadvantage can be eliminated. In detecting defects according to this invention, as described above, a defect marking of a material containing a fluorescent pigment is applied to a defective portion of the billet surface. In a darkroom, ultraviolet rays are projected onto the billet surface to excite the fluorescent pigment of the defect marking so as to generate fluorescent radiation. The defect can be detected by detecting such fluorescent radiation through a filter. This method makes it possible to more accurately detect defects on billets. | An automatic deseaming apparatus for an elongate block of metallic material comprises a defect marking detector for detecting defect markings which consist of a material containing a fluorescent pigment and have been deposited on defects in the surface of the block, a defect marking position detector for detecting the positions of the defects, a memory for storing the positions of the defect markings which are within the entire area or a predetermined one of segmented areas of the surface of the block, and a grinding controller for controlling reciprocative grinding action in the direction of the longitudinal axis of the block according to the defect marking informations stored in the memory. | 1 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention includes two processes which are useful in the production of midazolam.
2. Description of the Related Art
U.S. Pat. Nos. 4,280,957 and 4,377,523 disclose midazolam (VII) and processes for its production.
J. Heterocyclic Chem., 13, 433 (1976) discloses the conversion of the amino benzophenone starting material (I) to the corresponding nitro-nitrone (IV). The amino benzophenone (I) was transformed to the corresponding dihydroquinazoline which is then reacted with manganese dioxide to form the quinazoline (III). The quinazoline (III) is then transformed to the corresponding nitroolefin (IV) by reaction with lithium amide and nitromethane in dimethylsulfoxide.
J. Org. Chem., 43, 936 (1978) discloses the conversion of the nitroolefin (IV) to midazolam (VII). The nitroolefin (IV) is reduced to the amine (V) by catalytic hydrogenation. The amine (V) is transformed to the corresponding benzodiazepine (VI) by known methods. The benzodiazepine (VI) is then oxidized to midazolam (VII) in about 58% yield by use of manganese dioxide.
Aldrichimica Acta, 23(1), 13-19 (1990) discloses various reactions where "TPAP" is used as the catalyst for oxidation of alcohols. Example 41 discloses the oxidation of a 1-hydroxy-3-benzyloxycyclohexane derivative to the corresponding α, β-unsaturated cyclohexanone. Tetrahedron Letters, 35(35), 6567-6570 (1994) discloses oxidation of indoline to produce indole by use of TPAP. The use of TPAP in the present invention is in a more complex ring system and it is advantageous to pretreat the TPAP with an alcohol before usage.
J. Org. Chem., 40(2), 153 (1975) discloses compound 10 which is similar to the midazolam-nitrone (IX) of the present invention but it does not have a fluorine atom required for pharmacological activity.
SUMMARY OF INVENTION
Disclosed is an alkoxy compound of the formula (II) ##STR2## where X 1 is --Cl or --Br, and where X2 is C 1 -C 4 alkyl or --CH 2 --φ.
Also disclosed is a process for the production of the alkoxy compound of formula (II) where X 1 is --Cl or --Br; where X2 is C 1 -C 4 alkyl or --CH 2 --φ; which comprises:
(1) contacting 2-amino-5-chloro-2'-fluorobenzophenone (I) with an orthoester of the formula (XI)
X.sub.1 --CH.sub.2 --C(OX.sub.2).sub.3 (XI)
where X 1 and X2 are as defined above,
(2) heating the reaction mixture to a temperature of about 40 to about 90° in the presence of an acid catalyst.
Further disclosed is a process for the production of a quinazoline compound of formula (III) where X 1 is --Cl or --Br which comprises:
(1) contacting 2-amino-5-chloro-2'-fluorobenzophenone (I) with an orthoester of formula (XI)
X.sub.1 --CH.sub.2 --C(OX.sub.2).sub.3 (XI)
where X 2 is C 1 -C 4 alkyl or --CH 2 --φ and where X 1 is as defined above,
(2) heating the reaction mixture to a temperature of about 40° to about 90° in the presence of an acid catalyst,
(3) cooling the reaction mixture of step (2) to about +10° to about -20°,
(4) contacting the cooled reaction mixture of step (3) with hydroxylamine and a base.
Additionally disclosed is a process for the production of midazolam (VII) which comprises contacting 8-chloro-3,4-dihydro-6-(2-fluorophenyl)-1-methyl-4H-imidazo 1,5-a!benzodiazepine (VI) with TPAP.
Also disclosed are the useful intermediates in the production of midazolam which are:
7-chloro-5-(2-fluorophenyl)-2,3-dihydro-1H-1,4-benzodiazepine-2-methanamine-4-oxide (VIII),
8-chloro-6-(2-fluorophenyl)-3a,4-dihydro-1-methyl-3H-imidazo 1,5-a! 1,4!benzodiazepine-5-oxide (IX) and
8-chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo 1,5-a! 1,4!benzodiazepine-5-oxide (X).
Further disclosed is a process for producing TPAP in an activated form which comprises contacting unactivated TPAP with an alcohol.
DETAILED DESCRIPTION OF THE INVENTION
Midazolam (VII), 8-chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo 1,5-a!benzodiazepine, is known, see U.S. Pat. Nos. 4,280,957 and 4,377,523. These patents disclose methods to make midazolam. J. Heterocyclic Chem., 13, 433 (1976) and J. Org. Chem., 43, 936 (1978) also discloses a process to produce midazolam (VII).
One process of the present invention transforms the starting material benzophenone (I) to the corresponding alkoxy compound (II). Another process transforms the benzophenone (I) to the corresponding quinazoline (III) by an improved process. Another process is an improved method of oxidizing 8-chloro-3,4-dihydro-6-(2-fluorophenyl)-1-methyl-4H-imidazo 1,5-a!benzodiazepine (VI) to midazolam (VII). Still another process is a method to activate the TPAP reagent.
The first process involves the contacting the benzophenone (I), 2-amino-5-chloro-2'-fluorobenzophenone, with the orthoester (XI), X 1 --CH 2 --C(OX 2 ) 3 , where X 1 is --Cl or --Br, X 2 is C 1 -C 4 alkyl or --CH 2 --φ and heating the reaction mixture to a temperature of about 40 to about 90° in the presence of an acid catalyst. Suitable acids include any acid with a pK a of 0.5 to 4.8; preferred are acetic acid, chloroacetic acid, dichloroacetic, trichloroacetic, fluoroacetic, difluoroacetic, trifluroacetic acid and p-TSA; most preferred is acetic acid. It is preferred that X 1 is --Cl and that X 2 is C 1 alkyl. It is preferred the reaction mixture be heated to from about 55° to about 65°. It is preferred that the process be performed under reduced pressure. The reduced pressure is not required but it preferred to remove the alcohol (methanol) which is produced from --OX 2 (when X 2 is C 1 alkyl) and therefore help drive the reaction to completion. The reaction of the 2-amino-5-chloro-2'-fluorobenzophenone (I) with the orthoester (XI) produces the alkoxy compound (II). The alkoxy compound (II) can be isolated if desired (by methods known to those skilled in the art) if desired. However, it is preferred not to isolate the alkoxy compound (II) but to react it in situ without isolation to produce the corresponding quinazoline (III).
The alkoxy compound (II) is dissolved in a suitable solvent such as an alcohol, preferably C 1 -C 4 alcohols and cooled to about -10° to about 20°, preferably about 0°. This mixture is then reacted with hydroxylamine, either as the free base, salt or aqueous formulation. The commercially available 40% hydroxylamine is operable. If the salt is used the reaction is performed in the presence of a base. Suitable bases are those which will transform hydroxylamine in the salt form to hydroxylamine free base. These bases include bicarbonate, carbonate, hydroxide and salts of organic acids such as sodium acetate. The reaction mixture is acidified to a pH of about 5 with an acid such as acetic acid and stirred at about -10° to about 25°. The desired quinazoline (III) is isolated by means known to those skilled in the art.
This material can be use further in the process of CHART A without additional purification.
Another process of the invention is the oxidation of 8chloro-3,4-dihydro-6-(2-fluorophenyl)-1-methyl-4H-imidazo 1,5-a!benzodiazepine (VI) to midazolam (VII). It is preferred that 8-chloro-3,4-dihydro-6-(2-fluorophenyl)-1-methyl-4H-imidazo 1,5-a!benzodiazepine (VI) be in the free base form. If it is not, the salt form should be reacted with a suitable base to produce the free base of 8-chloro-3,4-dihydro-6-(2-fluorophenyl)-1-methyl-4H-imidazo 1,5-a!benzodiazepine (VI). The oxidative process of the present invention of transforming 8-chloro-3,4-dihydro6-(2-fluorophenyl)-1-methyl-4H-imidazo 1,5-a!benzodiazepine (VI) to midazolam (VII) uses a catalyst known as "TPAP" which is tetra-n-propylammonium perruthenate. The catalyst is prepared by contacting it with powdered sieves and a secondary alcohol in an appropriate solvent at a temperature of about 10° to about 60°. It is preferred that the powdered sieves be from three to about ten angstroms, preferably about 4 angstroms. Most all secondary alcohols without other functional groups that are liquids at 20°-25° are operable, preferred are i-propanol, cyclohexanol and i-butanol; more preferred is i-propanol. Most common non-reactive organic solvents are operable, preferred are acetonitrile and methylene chloride, more preferred is acetonitrile. Depending on reaction conditions, the preparation of the catalyst takes from a few minutes to days or weeks.
The oxidation process of transforming 8-chloro-3,4-dihydro-6-(2-fluorophenyl)-1-methyl-4H-imidazo 1,5-a!benzodiazepine (VI) to midazolam (VII) is performed by contacting 8-chloro-3,4-dihydro-6-(2-fluorophenyl)-1-methyl-4H-imidazo 1,5-a!benzodiazepine (VI) with the TPAP catalyst. It is preferred that the contacting be performed in the presence of molecular sieves. It is preferred that the molecular sieves be from three to about ten angstroms, preferably about 4 angstroms. It is preferred that the contacting be performed in the temperature range of about 10° to about 80° more preferably from about 30° to about 40°. Suitable solvents for the process include acetonitrile, methylene chloride, toluene and dimethylformamide and mixtures thereof.
CHART B discloses an alternate series of steps to transform the nitroolefin (IV) to midazolam. The nitroolefin (IV) is known, see J. Heterocyclic Chem., 13, 433 (1976). This process does not remove the "N-oxide" or "nitrone" group at this point but carries it along and it is removed in the final step producing midazolam (VII), see EXAMPLES 6-9.
Also disclosed is a process to make the "TPAP" catalyst operable. It was found that if used as purchased it was not operable. To activate the catalyst and make it useful it must be reacted with an alcohol, preferably a secondary alcohol, more preferably i-propyl alcohol. It is preferable to add molecular sieves of about three to about 10 angstrons, preferably about 4 angstroms and heat the TPAP and alcohol to about 25° to about 50° with stirring for a about two to about 24 hours. It is preferred to use about 22 to about 66 mL of alcohol for every 100 g of TPAP.
DEFINITIONS AND CONVENTIONS
The definitions and explanations below are for the terms as used throughout this entire document including both the specification and the claims.
I. CONVENTIONS FOR FORMULAS AND DEFINITIONS OF VARIABLES
The chemical formulas representing various compounds or molecular fragments in the specification and claims may contain variable substituents in addition to expressly defined structural features. These variable substituents are identified by a letter or a letter followed by a numerical subscript, for example, "Z 1 " or "R i " where "i" is an integer. These variable substituents are either monovalent or bivalent, that is, they represent a group attached to the formula by one or two chemical bonds.
For example, a group Z 1 would represent a bivalent variable if attached to the formula CH 3 --C(=Z 1 )H. Groups R i and R j would represent monovalent variable substituents if attached to the formula CH 3 --CH 2 --C(R i )(R j )--H. When chemical formulas are drawn in a linear fashion, such as those above, variable substituents contained in parentheses are bonded to the atom immediately to the left of the variable substituent enclosed in parenthesis. When two or more consecutive variable substituents are enclosed in parentheses, each of the consecutive variable substituents is bonded to the immediately preceding atom to the left which is not enclosed in parentheses. Thus, in the formula above, both R i and R j are bonded to the preceding carbon atom.
Chemical formulas or portions thereof drawn in a linear fashion represent atoms in a linear chain. The symbol "--" in general represents a bond between two atoms in the chain. Thus CH 3 --O--CH 2 --CH(R i )--CH 3 represents a 2-substituted-1-methoxypropane compound. In a similar fashion, the symbol "═" represents a double bond, e.g., CH 2 ═C(R i )--O--CH 3 , and the symbol ".tbd." represents a triple bond, e.g., HC.tbd.C--CH(R i )--CH 2 --CH 3 . Carbonyl groups are represented in either one of two ways: --CO--or --C(═O)--, with the former being preferred for simplicity.
The carbon atom content of variable substituents is indicated in one of two ways. The first method uses a prefix to the entire name of the variable such as "C 1 -C 4 ", where both "1" and "4" are integers representing the minimum and maximum number of carbon atoms in the variable. The prefix is separated from the variable by a space. For example, "C 1 -C 4 alkyl" represents alkyl of 1 through 4 carbon atoms, (including isomeric forms thereof unless an express indication to the contrary is given). Whenever this single prefix is given, the prefix indicates the entire carbon atom content of the variable being defined. Thus C 2 -C 4 alkoxycarbonyl describes a group CH 3 --(CH 2 ) n --O--CO--where n is zero, one or two. By the second method the carbon atom content of only each portion of the definition is indicated separately by enclosing the "C i -C j " designation in parentheses and placing it immediately (no intervening space) before the portion of the definition being defined. By this optional convention (C 1 -C 3 )alkoxycarbonyl has the same meaning as C 2 -C 4 alkoxy-carbonyl because the "C 1 -C 3 " refers only to the carbon atom content of the alkoxy group. Similarly while both C 2 -C 6 alkoxyalkyl and (C 1 -C 3 )alkoxy(C 1 -C 3 )alkyl define alkoxyalkyl groups containing from 2 to 6 carbon atoms, the two definitions differ since the former definition allows either the alkoxy or alkyl portion alone to contain 4 or 5 carbon atoms while the latter definition limits either of these groups to 3 carbon atoms.
II. DEFINITIONS
Midazolam refers to 8-chloro-6(-2-fluorophenyl)-1-methyl-4H-imidazo 1,5-a!benzodiazepine.
All temperatures are in degrees Centigrade.
TLC refers to thin-layer chromatography.
TPAP refers to tetra-n-propylammonium perruthenate.
HPLC refers to high pressure liquid chromatography.
THF refers to tetrahydrofuran.
DMSO refers to dimethylsulfoxide.
DMF refers to dimethylformamide.
DDQ refers to 2,3-dichloro-5,6-dicyano-1,4-benzoquinone.
DMAC refers to dimethylacetamide.
LDA refers to lithium diisopropylamide.
p-TSA refers to p-toluenesulfonic acid monohydrate.
TEA refers to triethylamine.
Magnesol refers to a commercial magnesium silicate adsorbant.
Solka floc refers to a commercial adsorbant.
Chromatography (column and flash chromatography) refers to purification/separation of compounds expressed as (support, eluent). It is understood that the appropriate fractions are pooled and concentrated to give the desired compound(s).
IR refers to infrared spectroscopy.
UV refers to ultraviolet spectroscopy.
PMR refers to proton magnetic resonance spectroscopy, chemical shifts are reported in ppm (δ) downfield from TMS.
CMR refers to C-13 magnetic resonance spectroscopy, chemical shifts are reported in ppm (δ) downfield from TMS.
NMR refers to nuclear (proton) magnetic resonance spectroscopy, chemical shifts are reported in ppm (δ) downfield from tetramethylsilane.
TMS refers to trimethylsilyl.
-φrefers to phenyl (C 6 H 5 ).
MS refers to mass spectrometry expressed as m/e, m/z or mass/charge unit. M+H! + refers to the positive ion of a parent plus a hydrogen atom. El refers to electron impact. CI refers to chemical ionization. FAB refers to fast atom bombardment.
When solvent pairs are used, the ratios of solvents used are volume/volume (v/v).
EXAMPLES
Without further elaboration, it is believed that one skilled in the art can, using the preceding description, practice the present invention to its fullest extent. The following detailed examples describe how to prepare the various compounds and/or perform the various processes of the invention and are to be construed as merely illustrative, and not limitations of the preceding disclosure in any way whatsoever. Those skilled in the art will promptly recognize appropriate variations from the procedures both as to reactants and as to reaction conditions and techniques.
EXAMPLE 1
Tetra-n-propylammonium perruthenate (TPAP)
Tetra-n-propylammonium perruthenate (100 mg) and 4 Å powdered sieves (200 mg) in acetonitrile (2.0 mL) and i-propanol (65 μL, 3.0 eq) is added. A slight exotherm to about 35° is noted and the mixture is stirred at 20°-25° for 4.5 hr and then is used as is.
EXAMPLE 2
Methyl-1chloromethyl-2'-amino-5'-chloro-2 "-fluorobenzophenone imidate (II)
Trimethyl-α-chloro-orthoacetate (XI, 3.49 mL) followed by acetic acid (100 μl) is added to 2-amino-5-chloro-2'-fluorobenzophenone (I, 3.47 g). The mixture is heated to about 60° with stirring for 1 hr during which a controlled vacuum (˜600 nm of vac.) is applied to remove the methanol being generated and give the title compound, TLC (silica gel; ethyl acetate/hexane, 20/80) R f =0.46.
EXAMPLE 3
2-Chloromethyl-4-(2-fluorophenyl)-6-chloro-1,2-dihydroquinazoline-3-oxide (III)
Methyl-1-chloromethyl-2'-amino-5'-chloro-2 "-fluorobenzophenone imidate (II, EXAMPLE 2) is dissolved in i-propanol (8 mL) and the resulting mixture is cooled to -5°. To this mixture is added, in one portion, a slurry of hydroxylamine hydrochloride (1.93 g) and sodium acetate (2.85 g) in water (7.8 mL). Acetic acid (3.5 mL) is added and the slurry is stirred for 18 hr at -5° to 16°. The crude product is precipitated by the addition of water (10 mL). The mixture is stirred at 23° for 1 hr and the solids are collected by (vacuum) filtration, washed with water/i-propanol (80/20, 10 mL) followed by i-propanol (7 mL) to give the title compound, TLC (silica gel; ethyl acetate/hexane, 20/80) R f =0.15.
EXAMPLE 4
8-Chloro-3,4-dihydro-6-(2-fluorophenyl)-1-methyl-4H-imidazo 1,5-a!benzodiazepine (VI)
A mixture of 8-chloro-3,4-dihydro-6-(2-fluorophenyl)-1-methyl-4H-imidazo 1,5-a!benzodiazepine methanesulfonate (VI, 100 g), ammonium hydroxide (10%, 500 mL) and methylene chloride (500 mL) are mixed for 10 min at 20°-25°. The methylene chloride layer is separated and the aqueous layer is extracted with methylene chloride (250 mL and 2×100 mL). The combined organic layers are dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure give the title compound.
EXAMPLE 5
Midazolam (VII)
A solution of trimethylamine oxide (1.111 g) in acetonitrile (30 mL) is heated to 35° and after 15 min. of equilibration, 5 mL of solvent is distilled off under reduced pressure. Then 4 Å powdered sieves (PREPARATION 1, 2.50 g) and 8-chloro-3,4-dihydro-6-(2-fluorophenyl)-1-methyl4H-imidazo , 1,5-a!benzodiazepine (VI, EXAMPLE 4, 1.639 g) is added using acetonitrile (about 5 mL) for a rinse. The above catalyst slurry from EXAMPLE 1 is added using acetonitrile (1 mL) for a rinse. This slurry is stirred under 200-300 mm of vacuum at 36°-42° for a total of 70 hr. The reaction is followed by HPLC on a 25 cm Prodigy ODS-2 column. After 69 hr, ethyl acetate (40 mL) is added and the warm reaction mixture was filtered through a 24 mm high×44 mm wide magnesol bed that is prepared in ethyl acetate. The first five-40 mL fractions of ethyl acetate are collected by gravity feed and since, TLC indicated they contained most of the midazolam, they are combined and concentrated under reduced pressure with a little heat. The concentrate is taken up in warm ethyl acetate (3.0 mL) and midazolam began to crystallize. Heptane (10 mL) is added in portions to increase the recovery. This slurry is remains at 20°-25° overnight and then, after standing 1 hr at -10°, the solids were collected, washed with heptane/ethyl acetate (3/1, 2×1.7 mL) and dried at 50° for 2 hr to give the title compound.
EXAMPLE 6
7-Chloro-5-(2-fluorophenyl)-2,3-dihydro-1H-1,4-benzodiazepine-2-methanamine-4-oxide (VIII)
To 7-chloro-1,3-dihydro-5-(2-fluorophenyl)-2-nitromethylene-2H-1,4-benzodiazepine (IV, J. Heterocyclic Chem., 13, 433 (1976)--compound 4b, 40 g, 115 mmol) and sodium borohydride (6.68 g, 176 mmol, 10 mesh) is added THF (100 ml) and i-propyl alcohol (50 ml). The resulting slurry is treated with a slow addition of water (3.1 ml, 176 mmol) while the temperature is maintained at about 23°. The reaction mixture is stirred for 2 hr. Water (9.3 ml) is added slowly to quench the reaction mixture. Methanol (50 ml) is used to facilitate transfer of the reaction mixture to a 500 ml capacity stainless steel Buchi hydrogenator. Raney nickel (40 g of water wet material) is added and the hydrogenation is preformed at 5° and 60 psig pressure. After 17 hr, HPLC showed the reduction is complete. The reaction mixture is removed from the Buchi and the hydrogenator is rinsed with methanol (200 ml). The combined reaction mixture and rinses are filtered through a 5 g pad of solka floc to remove spent catalyst. The catalyst cake is then rinsed with methanol (200 ml). The combined filtrate and rinses are concentrated. Water is added to the concentrate. The product is extracted from the aqueous layer using ethyl acetate (200 ml). The ethyl acetate extract is concentrated to near dryness to azeotrope any residual water. Finally, ethyl acetate (600 ml) is used to dissolve the crude product and the mixture is heated to 50°-60°. Then oxalic acid (10.36 g, 115 mmol) is added. The slurry that forms is stirred overnight at 20°-25° and is then cooled to 0° for 1 hr and the product is collected by vacuum filtration. The product is washed with ethyl acetate (100 ml) and dried at 40° in a vacuum oven to give the title compound as the oxalic salt, mp =144°-148°; TLC (methylene chloride/methanol/ammonium hydroxide, 90/10/1) R f =0.17.
EXAMPLE 7
8-Chloro-6-(2-fluorophenyl)-3a,4-dihydro-1-methyl-3H-imidazo 1,5-a! 1,4!benzodiazepine-5-oxide (IX)
A slurry of 7-chloro-5-(2-fluorophenyl)-2,3-dihydro-1H-1,4-benzodiazepine-2-methanamine-4-oxide oxalate salt (VIII, EXAMPLE 6, 35 g, 85 mmol) and triethylorthoacetate (23.5 ml, 128 mmol) in acetonitrile (175 ml) is stirred at reflux for 2 hr during which time the 7-chloro-5-(2-fluorophenyl)-2,3-dihydro-1H-1,4-benzodiazepine-2-methanamine-4-oxide (VIII) dissolves and ethanol/acetonitrile (about 75 ml) is removed by distillation under ordinary pressure. TLC and HPLC analysis shows the reaction is complete. The temperature is adjusted to 40° and methyl t-butyl ether (175 ml) is added dropwise over about 1 hr. The resulting slurry is cooled to 5°, stirred 1 hr, the solids are collected and are washed with t-butyl ether. The product is dried in the vacuum oven at 35° to give the title compound as the oxalate salt, mp=178°-180°; TLC (methylene chloride/methanol/ammonium hydroxide, 90/10/1) R f =0.28.
EXAMPLE 8
8-Chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo 1,5-a! 1,4!benzodiazepine-5-oxide (X)
The active TPAP is prepared by slurring three commercial TPAP samples (323 mg) in acetonitrile (3 ml) and treating each sample with i-propyl alcohol (211 μL).
8-Chloro-6-(2-fluorophenyl)-3a,4-dihydro-1-methyl-3H-imidazo 1,5-a! 1,4!benzodiazepine-5-oxide (IX, EXAMPLE 7, 20.00 g, 46 mmol) is partitioned between ammonium hydroxide (10%, 100 ml) and methylene chloride (100 ml). The layers are separated and the aqueous phase is extracted with additional methylene chloride (2×50 ml). The combined organic extracts are concentrated to dryness and the solids are redissolved in acetonitrile (200 ml). To this mixture is added powdered molecular sieves (20 g) and trimethylamine-N-oxide (7.6 g, 68 mmol) followed by one activated TPAP sample from above. The reaction mixture is heated to reflux and the next sample of TPAP and an additional trimethylamine-N-oxide (7.66 g, 68 mmol) is added after 6 hr and again after 18 hr. The mixture is heated at reflux for 42 hr at which time HPLC shows only 6% starting material remaining. The reaction mixture is concentrated to dryness and ethyl acetate (100 ml) is added back. The slurry is chromatographed (magnesol, 100 g) until no more product is eluding with ethyl acetate. The combined column fractions are concentrated to about 60 ml and heptane (140 ml) is added slowly. The product is cooled to -15° overnight, collected by vacuum filtration, washed with cold heptane and dried in the vacuum oven at 40° to give the title compound.
EXAMPLE 9
Midazolam (VII)
To a mixture of 8-chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo 1,5-a! 1,4!benzodiazepine-5-oxide (X, EXAMPLE 8, 3.42 g, 10 mmol) and sodium hypophosphite (5.3 g, 50 mmol) in i-propyl alcohol (34 ml) and water (34 ml) is added 5% palladium on carbon (342 mg, 53% water wet). The slurry is stirred at 23° for 2 hr. TLC and HPLC analysis shows the reaction is complete. The reaction mixture is filtered through a small bed of solka floc and concentrated to near dryness. The concentrate is partitioned between water (50 ml) and ethyl acetate (50 ml). The ethyl acetate layer is collected and the aqueous layer extracted with ethyl acetate (50 ml). The combined ethyl acetate extracts are concentrated and then redissolved in hot i-isopropyl alcohol (12 ml). The mixture is cooled gradually to 20°-25°, seeded and cooled to -15° overnight. The solids are collected, washed with cold i-propyl alcohol and dried in the vacuum oven to give the title compound, TLC (methylene chloride/methanol/ammonium hydroxide, 90/10/1) R f =0.59; HPLC (methanol 0.05M ammonium hydroxide/acetonitrile, 55/35/10) R t =9.5 min.
EXAMPLE 10
7-Chloro-5-(2-fluorophenyl)-2,3-dihydro-1H-1,4-benzodiazepine-2-methanamine-4-oxide (VIII)
Following the general procedure of EXAMPLE 6 and making non-critical variations (using 15° and 90 psig), the title compound is obtained, NMR (300 MHz, DMSO) 2.62, 3.83, 4.15, 6.48, 6.60, 6.95, 7.10, 7.26, 7.45 and 8.29δ; CMR (DMSO) 160.4, 158.5, 144.9, 137.3, 131.6, 130.6, 129.2, 128.9, 124.4, 123.1, 122.9, 120.6, 119.9, 117.8, 115.9, 115.7, 64.4, 54.5 and 45.8 δ.
EXAMPLE 11
8-Chloro-6-(2-fluorophenyl)-3a,4-dihydro-1-methyl-3H-imidazo 1,5-a! 1,4!benzodiazepine-5-oxide (IX)
Following the general procedure of EXAMPLE 7 and making non-critical variations (trimethylorthoacetate in place of triethylorthoacetate), the title compound is obtained, NMR (300 MHz, CDCl 3 ) 1.78, 2.68, 3.95, 4.21, 4.60, 4.76, 6.99, 7.43 and 7.59δ; CMR (CDCl 3 ) 178.4, 161.7, 161.2, 158.4, 138.1, 137.8, 134.4, 132.1, 131.9, 131.4, 130.1, 124.3, 120.8, 120.6, 116.7, 116.4, 69.3, 66.0, 57.5, 29.7 and 14.6 δ.
EXAMPLE 12
8-Chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo 1,5-a! 1,4!benzodiazepine-5-oxide (X)
Following the general procedure of EXAMPLE 8 and making non-critical variations, the title compound is obtained, mp =224°-226°; TLC (methylene chloride/methanol/ammonium hydroxide, 90/10/1) R f =0.49; NMR (300 MHz, CDCl 3 ) 7.3, 5.04 and 2.59δ; CMR (CDCl 3 ) 161.75, 158.4, 144.5, 134.9, 133.4, 132.2, 132.0, 131.9, 131.5, 130.5, 130.3, 129.9, 1290.6, 126.0, 124.2, 124.1, 121.1, 121.0, 116.5, 116.2, 64.1, 59.9, 25.3 and 14.9δ. ##STR3## | The present invention discloses new processes in the preparation of midazolam (VII), ##STR1## a commercially important pharmaceutical, as well a new intermediates in those processes from a known benzophenone (I) starting material. | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a continuous casting apparatus.
2. Description of the Prior Art
During a continuous casting operation, molten material is teemed into a cooled mold where the material is at least partially solidified to form a continuously cast strand. The mold, which is oscillated during continuous casting, is supported by a mold table driven by an oscillator.
In a continuous casting apparatus for the casting of wide products, e.g., slabs having a width greater than 60 inches, the mold table consists of two parts which are spaced from one another. For proper operation, the mold table parts must be oscillated synchronously.
One conventional system for oscillating the mold table parts employs two eccentrics. Each of the eccentrics acts on a push rod which, in turn, is coupled to one of the mold table parts. The push rods have adjustable lengths to permit leveling of the mold table parts. A gear mechanism is located between the eccentrics, and two shafts connect the gear mechanism to the respective eccentrics. The gear mechanism is driven by an electric motor.
This electromechanical oscillating system is associated with substantial difficulties arising from the fact that the two mold table parts must be oscillated in synchronism. To begin with, all elements of the drive system, including the eccentrics, couplings, bushings and keyways, must be machined with a high degree of precision. Furthermore, all elements of the drive system must be very accurately aligned. Aside from these difficulties, the cost of the system is high because the system is complex and two eccentrics are required.
Another conventional oscillating system employs two hydraulic cylinder-and-piston units which are coupled to respective ones of the mold table parts. The hydraulic units, which extend and retract to generate an oscillating motion, are supplied with hydraulic fluid from a common reservoir.
The need for synchronous movement of the mold table parts creates substantial problems for the hydraulic system also. The hydraulic units must not only be machined with a high degree of precision but must be equipped with electronic position feedback sensors and a very complex servo mechanism. Moreover, excellent tuning and continuous readjustments are required. Additionally, this system is expensive because considerable maintenance is necessary and two cylinder-and-piston units must be used.
SUMMARY OF THE INVENTION
It is an object of the invention to simplify systems for the synchronous oscillation of spaced parts of a mold carrier or table.
The preceding object, as well as others which will become apparent as the description proceeds, are achieved by the invention.
One aspect of the invention resides in a continuous casting apparatus. The apparatus comprises a mold carrier or table having two spaced parts, means for oscillating the mold carrier parts, and means for synchronizing movement of the mold carrier parts. The synchronizing means includes a synchronizing member which is mounted for movement as a unit and is coupled to the mold carrier parts.
The synchronizing member constrains the mold carrier parts to move as a unit, i.e., synchronously, since the synchronizing member is coupled to these parts and itself moves as a unit. This allows the mold carrier parts to be oscillated by a single oscillation generator, e.g., a single eccentric or single cylinder-and-piston unit, which acts on the synchronizing member or another member coupled to the mold carrier parts. A single oscillation generator eliminates the complexities arising from the use of a discrete oscillation generator for each mold part.
Another aspect of the invention resides in a method of oscillating a mold carrier having two spaced parts. The method comprises the steps of generating an oscillating motion at a predetermined location, and transferring the motion from such location to the mold carrier parts so that the latter oscillate substantially synchronously.
The method can further comprise the step of preventing substantial transfer of stresses due to thermal expansion of the mold carrier parts from the mold carrier parts to the predetermined location.
The step of transferring motion may include advancing the oscillating motion to the mold carrier parts by way of a synchronizing member mounted for movement as a unit and coupled to the mold carrier parts.
The oscillating motion is preferably generated at a location substantially midway between the mold carrier parts.
Additional features and advantages of the invention will be forthcoming from the following detailed description of preferred embodiments when read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a prior art system for oscillating a mold carrier having two spaced parts.
FIG. 2 is a side view of one embodiment of a system in accordance with the invention for oscillating a mold carrier having two parts.
FIG. 3 is a sectional view along the line III--III of FIG. 2 with the visible components of the oscillating system spread apart for clarity.
FIG. 4 is similar to FIG. 3 but illustrates another embodiment of an oscillating system according to the invention.
FIG. 5 is similar to FIG. 2 but shows an additional embodiment of an oscillating system in accordance with the invention.
FIG. 6 is similar to FIGS. 2 and 5 but illustrates a further embodiment of an oscillating system according to the invention.
FIG. 7 is a sectional view along the line VII--VII of FIG. 6.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, the numeral 10 identifies a prior art system which constitutes part of a continuous casting apparatus and is used to oscillate or reciprocate a non-illustrated mold of the apparatus. The oscillating system 10 includes a mold table or carrier having two parts 12a and 12b which are spaced from one another. The mold table part 12a is mounted on a lever arm 14a and the mold table part 12b on a lever arm 14b.
A push rod or moving member 16a is connected to the mold table part 12a and a push rod or moving member 16b to the mold table part 12b. The push rod 16a is mounted on an eccentric mechanism 18a and the push rod 16b on an eccentric mechanism 18b. The eccentric mechanism 18a is coupled to a gear reducer 20 by a drive shaft 22 while the eccentric mechanism 18b is coupled to the gear reducer 20 by a second drive shaft not visible in FIG. 1. The gear reducer 20 is driven by an electric motor 24. A counterweight 26 suspended from the lever arms 14a,14b serves to reduce the power requirements of the motor 24.
When the motor 24 operates, the gear reducer 20 rotates the eccentric mechanisms 18a,18b by way of the drive shaft 22 and the second drive shaft. As the eccentric mechanisms 18a,18b rotate, the push rods 16a,16b are moved up-and-down. The push rods 16a,16b impart a seesaw motion to the lever arms 14a,14b which, in turn, oscillate the mold table parts 12a,12b.
The mold table parts 12a,12b must oscillate synchronously since otherwise the mold will wobble resulting in a variety of problems. However, as outlined previously, it is very difficult to achieve synchronous oscillation with the oscillating system 10. Thus, the eccentric mechanisms 18a,18b, as well as the couplings, bushings and keyways which serve to support the eccentric mechanisms 18a,18b and to connect the latter to the gear reducer 20, must be machined and aligned with extreme accuracy. The oscillating system 10 is also costly because it is complex and requires two eccentric mechanisms 18a,18b.
In another prior art oscillating system, the push rods 16a,16b and eccentric mechanisms 18a,18b are replaced by hydraulic cylinder-and-piston units while the gear reducer 20 and motor 24 are replaced by a hydraulic fluid reservoir. This prior art hydraulic oscillating system likewise poses great challenges in attempting to achieve synchronous oscillation of the mold table parts 12a,12b. To begin with, the hydraulic cylinder-and-piston units must be machined with a high degree of precision. Furthermore, the hydraulic units must be equipped with electronic position feedback sensors and a complicated servo mechanism. In addition, the system requires excellent tuning and continuous readjustments. The system is, moreover, expensive since significant maintenance is necessary and two cylinder-and-piston units are required.
The invention intends to provide a simpler system for synchronously oscillating two mold table or mold carrier parts.
FIGS. 2 and 3 illustrate one embodiment of an oscillating or reciprocating system in accordance with the invention. The oscillating system, which is denoted by the numeral 110, is supported on a foundation or base 112. The oscillating system 110 functions to oscillate or reciprocate a mold table or carrier having two parts 114 which are spaced from one another. Only one of the mold table parts 114 is visible.
The base 112 carries two spaced columns or pillars 116, and a lever arm 118 is pivotally mounted on each column 116 via a pivot 120. The pivots 120 are located between the ends of the lever arms 118. One end of each lever arm 118 is pivotally connected to a respective mold table part 114 by way of a pivot 122.
A stabilizing arm 124 is mounted on each column 116 above the respective lever arm 118. One end of each stabilizing arm 124 is pivotally connected to the respective column 116 via a pivot 126 while the other end is pivotally connected to the respective mold table part 114 via a pivot 128. The stabilizing arms 124 help to stabilize the mold table parts 114.
The end of each lever arm 118 remote from the respective mold table part 114 is pivotally connected, by means of a journal bearing 130, to one end of a push rod or moving member 132. The push rods 132 are adjustable, and the lengths of the push rods 132 can be fixed at any of a large number of values. To this end, the push rods 132 are provided with adjusting nuts 132a. The adjustability of the push rods 132 allows the mold table parts 114 to be leveled.
The end of each push rod 132 remote from the respective lever arm 118 is pivotally connected, via a journal bearing 134, to an operating level or member 136. Each of the operating levers 136 is fast with an elongated synchronizing member 138. The synchronizing member 138 includes a stepped synchronizing shaft or synchronizing element 140 having two end portions 140a of a first diameter, two anchoring portions 140b of a second diameter, two main portions 140c of a third diameter, two bearing portions 140d of a fourth diameter and a middle portion 140e of a fifth diameter. Each anchoring portion 140b is located between an end portion 140a and a main portion 140c, and each main portion 140c is located between an anchoring portion 140b and a bearing portion 140d. The bearing portions 140d are located between the middle portion 140e and the respective main portions 140c. The diameter of the middle portion 140e exceeds the diameter of the bearing portions 140d, and the diameter of the bearing portions 140d exceeds the diameter of the main portions 140c. Similarly, the diameter of the bearing portions 140c exceeds the diameter of the anchoring portions 140b which, in turn, exceeds the diameter of the end portions 140a.
The end portions 140a of the synchronizing shaft 140 serve as journals and are mounted for rotation in respective journal bearings 142. The bearing portions 140d of the synchronizing shaft 140 likewise function as journals and are respectively mounted for rotation in fixed bearings 144.
The anchoring portions 140b of the synchronizing shaft 140 serve as anchors for the operating levers 136. The operating levers 136 can, for instance, be keyed to the anchoring portions 140b.
In addition to the synchronizing shaft 140, the synchronizing member 138 includes an actuating handle or element. The actuating handle includes two plates or components 146a and 146b which are fast with the synchronizing shaft 140. The actuating handle 146a,146b is fixed to the middle portion 140e of the synchronizing shaft 140 and is angularly offset from the operating levers 136 circumferentially of the synchronizing shaft 140. In the illustrated embodiment, the actuating handle 146a,146b is offset 90 degrees from the operating levers 136 as seen in FIG. 2. The actuating handle 146a,146b is located midway between the lever arms 118.
The synchronizing member 138 rotates as a unit, that is, the synchronizing shaft 140 and actuating handle 146a,146b rotate in tandem.
The actuating handle 146a,146b is pivotally connected to one end of a push rod or drive member 148 by means of a pivot 150, and this end of the push rod 148 is received between the plates 146a and 146b of the actuating handle 146a,146b. The other end of the push rod 148 is connected to an eccentric 152 constituting a member for generating oscillating or reciprocating motion. The eccentric 152 is driven in rotation by an electric motor 154 via a gear reducer 156.
The operation of the oscillating system 110 is as follows:
The motor 154 is switched on and rotates the eccentric 152 by way of the gear reducer 156. The eccentric 152, which is connected to the push rod 148, reciprocates the push rod 148 longitudinally. As the push rod 148 reciprocates, the push rod 148 rotates the actuating handle 146a,146b back-and-forth on the axis of rotation of the synchronizing shaft 140.
Since the actuating handle 146a,146b is fast with the synchronizing shaft 140, the synchronizing shaft 140 rotates back-and-forth with the actuating handle 146a,146b. The synchronizing shaft 140, in turn, rotates the two operating levers 136 back-and-forth inasmuch as the operating levers 136, which are located at either end of the synchronizing shaft 140, are fixed to the latter. The back-and-forth motion of the operating levers 136 causes the two push rods 132, which are pivotally connected to the operating levers 136, to reciprocate longitudinally. Consequently, the two lever arms 118 pivotally connected to the respective push rods 132 are pivoted back-and-forth on the pivots 120. The ends of the lever arms 118 which are remote from the push rods 132 accordingly move up-and-down thereby synchronously oscillating the two mold table parts 114 mounted at such ends.
The oscillating system 110 allows the mold table parts 114 to oscillate in synchronism employing only the one eccentric 152 to generate an oscillating motion. By avoiding the use of two eccentrics as in the prior art oscillating system 10 of FIG. 1, the machining and alignment problems associated with the presence of two eccentrics are eliminated. The synchronizing member 138, which makes it possible to oscillate the two mold table parts 114 in synchronism using the single eccentric 152, also enables the oscillating system 110 of the invention to be considerably simplified as compared to the prior art oscillating system 10.
The journal bearings 130 joining the lever arms 118 to the push rods 132, the journal bearings 134 joining the push rods 132 to the operating levers 136, and the journal bearings 142 supporting the synchronizing shaft 140 allow the mold table parts 114 to undergo thermal expansion without affecting the actuating handle 146a,146b and the push rod 148.
In FIG. 4, which shows another embodiment of the oscillating system of the invention, the same reference numerals as in FIGS. 2 and 3 plus 100 are used to identify similar elements.
The oscillating system of FIG. 4 differs from that of FIGS. 2 and 3 primarily in that the elongated synchronizing member 238 includes a pair of torque tubes 240 rather than a shaft such as the synchronizing shaft 140. One end of each torque tube 240 is provided with a journal 240a which rides in a respective journal bearing 242 while the other end of each torque tube 240 is provided with a journal 240d which rides in a respective fixed bearing 244. The fixed bearings 244 are situated between the two torque tubes 240.
One of the torque tubes 240 is further formed with a flange 246a and the other of the torque tubes 240 with a flange 246b. Each of the flanges 246a,246b adjoins the associated journal 240d and is located between the latter and the respective journal 240a. The flanges 246a,246b are in alignment, and a spacer 258 in the form of a block is disposed between the flanges 246a,246b. The flanges 246a,246b abut the block 258, and each of the flanges 246a,246b is rigidly connected to the block 258 by bolts or fastening elements 260. A rigid connection is thus established between the two torque tubes 240. The block 258 functions to create and maintain a gap between the flanges 246a,246b, and the block 258 is designed so that the gap can accommodate the fixed bearings 244 for the journals 240d. The gap is sufficiently wide that the journals 240d can fit in the gap side-by-side without contacting one another.
The flanges 246a,246b, block 258 and bolts 260 together define an actuating handle or element corresponding to the actuating handle 146a,146b of FIGS. 2 and 3.
The block 258 is formed with an opening 262, and the push rod 248 projects through the opening 262 with clearance into the interior of the block 258. The pivot pin 250 pivotally connecting the push rod 248 to the actuating handle 246a,246b,258,260 passes through the flanges 246a,246b and the block 258 into the push rod 248.
The synchronizing member 238, which comprises the torque tubes 240 and the actuating handle 246a,246b,258,260, rotates as a unit. Thus, the torque tubes 240, flanges 246a,246b, block 258 and bolts 260 rotate in synchronism.
By replacing the synchronizing shaft 140 of solid cross section with the torque tubes 240, the weight of the synchronizing member 238 can be reduced. Moreover, the torque tubes 240 can have a relatively large diameter thereby enabling the flanges 246a,246b and the operating levers 236 to be easily and inexpensively welded to the torque tubes 240. In addition, the torque tubes 240 make it possible for the journal bearings 242 and the fixed bearings 244 to have the same size which allows costs to be reduced further.
FIG. 5, where the same reference numerals as in FIGS. 2 and 3 plus 200 are used to denote similar elements, illustrates an additional embodiment of the oscillating system of the invention.
The oscillating system 310 of FIG. 5 differs from that of FIGS. 2 and 3 mainly in that the electric motor 154, gear reducer 156, eccentric 152 and push rod 148 are replaced by a double-acting hydraulic cylinder-and-piston unit 364. The cylinder-and-piston unit 364, which is connected to a non-illustrated hydraulic fluid reservoir or source, constitutes a member for generating an oscillating or reciprocating motion. This motion is produced by alternately extending and retracting the cylinder-and-piston unit 364.
One end of the cylinder-and-piston unit 364 is pivotally connected to the actuating handle 346a,346b (346b not visible in FIG. 5) by the pivot 350. The other end of the cylinder-and-piston unit 364 is pivotally connected, by way of a pivot 366, to a bracket or pedestal 368 fixed to the foundation 312.
The cylinder-and-piston unit 364 can be used with the synchronizing member 238 of FIG. 4 as well as the synchronizing member 138 of FIGS. 2 and 3.
The oscillating system 310 of FIG. 5 permits the mold table parts 314 to be oscillated synchronously employing only the one cylinder-and-piston unit 364 to produce an oscillating motion. The use of the single cylinder-and-piston unit 364, rather than the two cylinder-and-piston units found in the prior art hydraulic oscillating systems, makes it unnecessary to machine the cylinder-and-piston unit 364 with the same degree of precision as the prior art cylinder-and-piston units. Moreover, the electronic position feedback sensors and complex servo mechanisms of the prior art hydraulic oscillating systems can be eliminated. The oscillating system 310 of FIG. 5 also does not require the fine tuning, continuous readjustment and high maintenance of these prior art systems.
In FIGS. 6 and 7, where a further embodiment of the oscillating system of the invention is shown, the same reference numerals as in FIGS. 2 and 3 plus 300, or the same reference numerals as in FIG. 5 plus 100, are used to identify similar elements.
The synchronizing member 438 of FIGS. 6 and 7 consists of a single torque tube 440 which is provided with a journal 440a at either end. The journals 440a are supported for rotation in the journal bearings 442.
An elongated load-bearing or bridge member 470 extends in parallelism with the synchronizing member 438 at a spacing therefrom. The load-bearing member 470 includes a tie beam or element 472 in the form of a tube. The tube 472 is rectangular and has two opposed parallel narrow walls 474a and 474b as well as two opposed parallel wide walls 476. The tube 472 is disposed to the side of the push rods 432 remote from the synchronizing member 438, and the tube 472 is arranged with one of the wide walls 476 facing the push rods 432 and with the narrow wall 474a facing the foundation 412. The tube 472 is inclined in such a manner that the wide walls 476 are parallel to the push rods 432 and the narrow walls 474a,474b are perpendicular to the push rods 432. However, the tube 472 need not be so inclined.
The ends of the tube 472 are closed by rectangular plates or walls 478 which are fast with the tube 472, and the end plates 478 project beyond the narrow tube wall 474a towards the foundation 412. The operating levers 436 project to the side of the push rods 432 remote from the synchronizing member 438, and the projecting part of each lever 436 is rigidly connected to the projecting part of a respective end plate 478.
A reinforcing plate or element 480 is mounted on the narrow tube wall 474a at the middle of the tube 472. Two lugs or plates 446a and 446b are located beneath the reinforcing plate 480 and are rigidly fixed thereto. The lugs 446a,446b together constitute an actuating handle or element such as the actuating handle 146a,146b of FIG. 1. The lugs 446a,446b are arranged side-by-side with spacing to define a gap, and one end of the hydraulic cylinder-and-piston unit 464 extends into the gap. This end of the cylinder-and-piston unit 464 is pivotally connected to the actuating handle 446a,446b by the pivot 450.
The operation of the oscillating system 410 of FIGS. 6 and 7 is as follows:
The cylinder-and-piston unit 464 is alternately extended and retracted to generate a reciprocating or oscillating motion. This causes the load-bearing member 470 to move back-and-forth since the cylinder-and-piston unit 464 is connected to the actuating handle 446a,446b which, in turn, is fast with the tube 472 of the load-bearing member 470. Due to the fact that the end plates 478 of the load-bearing member 470 are rigid with the operating levers 436, the load-bearing member 470 rotates the operating levers 436 back-and-forth.
The back-and-forth motion of the operating levers 436 causes the push rods 432, which are pivotally connected to the operating levers 436, to reciprocate longitudinally. As the push rods 432 reciprocate, the lever arms 418 are rotated back-and-forth on the pivots 420 inasmuch as the lever arms 418 are pivotally connected to the push rods 432. The back-and-forth rotation of the lever arms 418 results in an up-and-down motion of the ends of the lever arms 418 remote from the push rods 432. Since such lever arm ends carry the mold table parts 414, the mold table parts 414 are accordingly oscillated.
In addition to being pivotally connected to the push rods 432, the operating levers 436 are fast with the synchronizing member 438. Consequently, the operating levers 436, push rods 432 and lever arms 418 are constrained to move in synchronism thereby causing the mold table parts 414 to oscillate synchronously.
In the oscillating system 410, central loading of the synchronizing member 438 is avoided. This eliminates the need for bearings at the midsection of the synchronizing member 438.
The use of tubes 440 and 472 for the synchronizing member 438 and load-bearing member 470 allows the weight of the oscillating system 410 to be reduced. However, it is possible to replace the tube 440 and/or the tube 472 with a shaft or other component of solid cross section.
The hydraulic cylinder-and-piston unit 464 of the oscillating system 410 can be replaced by the electric motor 154, gear reducer 156, eccentric 152 and push rod 148 of FIG. 2.
Various other modifications are conceivable within the meaning and range of equivalence of the appended claims. | A mold table for the continuous casting of large strands has two separate parts. The mold table parts are coupled to opposite ends of an elongated rigid rotatable member by respective linkages. A drive oscillates the rotatable member which, in turn, constrains the mold table parts to oscillate synchronously. | 1 |
FIELD OF INVENTION
[0001] The invention relates to a process for the repair of defects in castings. In particular, this relates to a process for the repair of defects in engine and airfoil components and parts.
BACKGROUND OF THE INVENTION
[0002] Modern gas turbine engines and their respective components, operate at high rotational speeds and high temperatures for increased performance and efficiency. Thus, the materials from which these components are made must be able to withstand severe operating environments.
[0003] Most high temperature gas turbine components are made of nickel base superalloys, which are alloys that are specifically developed for applications involving extreme temperatures and mechanical stresses. Superalloys are often cast, by an appropriate process, into the component shape. For example, directional solidification is known in the art. This casting technique aligns grain boundaries parallel to the stress axis. This alignment enhances elevated temperature strength by increasing resistance to creep and minimizing grain boundary failure initiation sites.
[0004] An extension of the above-described technique is single crystal casting. Casting of alloys in single crystal form eliminates internal crystal boundaries in the finished article. Single crystal turbine blades and vanes possess superior characteristics, such as strength, ductility and crack resistance at high operating temperatures. Thus, single crystal articles are extensively used in components of gas turbine engines.
[0005] Although single crystal engine components are desirable, they are extremely costly to manufacture. Defects often occur during manufacturing, as well as after extensive engine operation. Upon detection of certain critical defects, such as cracks, the component must be repaired, replaced or otherwise scrapped. This incurs a significant expense and is undesirable.
[0006] The fabrication of gas turbine components, for example blades or nozzles, can occur by various processes, such as by investment casting. In investment casting of relatively complex airfoil parts, intentional defects, such as “bumper holes,” may be required for casting the part, as is known in the art. The bumper holes constitute an “intentional” defect used to hold the casting core during casting of relatively complex articles.
[0007] Ceramic bumpers are added to the ceramic core to limit the maximum distortion or motion of the core relative to the mold, to achieve a control of wall thickness in a cavity. The bumper holds the casting core in place during casting. After the core is removed, a thin spot remains where a bumper was located. This thin region is removed forming a “bumper hole” that can then be repaired to achieve the full required wall thickness.
[0008] The bumper holes should be repaired when the casting is completed and prevent coolant leakage and to make the casting usable. Accordingly, post-processing of the investment casting is needed to remove the bumper holes.
[0009] Several proposed repair methods for cracks in components have been proposed. For example, European patent application EP 0740976 (EP 976) discloses a method of repairing single crystal metallic articles using a laser technique. EP 976 attempts to overcome problems associated with the laser weld repair of these articles by optimizing laser parameters. In particular, EP 976 provides a molten material at the crack, solidifies the molten material, and provides a re-melt of a once solidified melt from a second energy source, in an attempt to provide an acceptable stress-free repair. However, EP 976 does not discuss a repair of as-cast articles. Further, EP 976 does not provide for removal of defects, and does not provide for melting of the casting to insure a sound metallurgical bond and physical repair. Furthermore, the second application of energy in EP 976 is costly and inefficient with respect to both in time and power consumption.
[0010] It is desirable to reduce overall costs involved with casting. This cost reduction includes avoiding scrapping newly cast articles with manufacturing defects. This cost reduction also includes efficiently repairing, rather than scrapping and re-casting, parts with defects resulting from use of the part.
SUMMARY DESCRIPTION OF THE INVENTION
[0011] Accordingly, it is desirable to provide a method for repairing defects in airfoils that reduces costs associated with the production of airfoils.
[0012] Further it is desirable to provide a method for repairing defects in airfoil components and parts, which are produced by investment casting processes, that reduces costs associated with the production of said airfoil components.
[0013] It is also desirable to provide a process with means to repair defects, both intentional, such as “bumper hole” defects, or unintentional, such as freckles and inclusions from the casting process or cracks resulting from use, thereby minimizing the need to scrap and recast. A reduction in process costs results in a savings to the manufacturer, and ultimately to the customer.
[0014] Therefore, it is desirable to provide a method of repairing defects in cast articles, where the defect comprises at least one of a manufacturing, intentional, or service-induced defect. The cast article comprises a casting core and a casting, the casting core comprising a ceramic bumper that creates a thin region in the casting comprising the defect. The method of repairing the defect comprises locating a defect at a defect area in the cast article; removing an area of the casting at the defect area; removing an area of the casting core including the bumper at the defect area, where removing the area of the casting at the defect area and removing an area of the casting core including the bumper at the defect area to creates a hole through a wall of the casting; positioning repair material in the hole; heating the defect area, so the repair material and the area of the become molten; and re-solidifying the molten material to form a repaired casting.
[0015] Also, it is desirable to provide a method, similar to that above, but without forming the hole, to repair surface defects, such as voids, freckles and inclusions.
[0016] Further, it is desirable to provide a repaired article formed by the methods, as embodied by the invention.
[0017] These and other aspects, advantages and salient features of the invention will become apparent from the following detailed description, which, when taken in conjunction with the annexed drawings, disclose embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] While the novel features of this invention are set forth in the following description, the invention will now be described from the following detailed description of the invention taken in conjunction with the drawings, in which:
[0019] [0019]FIG. 1 is a side-sectional view of an intentional defect, for example, a thin region in a casting, for example resulting from a ceramic bumper;
[0020] [0020]FIG. 2 is a side-sectional view of a “bumper hole” made to remove the cast product and thin region in a process, as embodied by the invention;
[0021] [0021]FIG. 3 is a side-sectional view of a repair filler material in the bumper hole of FIG. 2;
[0022] [0022]FIG. 4 is a side-sectional view of molten repair filler material and cast material;
[0023] [0023]FIG. 5 is a flow chart of a process for repairing intentional defects, for example a bumper hole, as embodied by the invention;
[0024] [0024]FIG. 6 is a side-sectional view of a surface defect in a casting;
[0025] [0025]FIG. 7 is a side-sectional view of a surface defect repair filler material in the surface defect of FIG. 6;
[0026] [0026]FIG. 8 is a side-sectional view of a molten surface defect repair filler material and cast material;
[0027] [0027]FIG. 9 is a flow chart of a process for repairing surface defects, as embodied by the invention;
[0028] [0028]FIG. 10 is a side-sectional view of a casting formed using an intentional defect, for example, a bumper hole, with the casting core removed;
[0029] [0029]FIG. 11 is a side-sectional view of a hole in the casting, as embodied by the invention;
[0030] [0030]FIG. 12 is a side-sectional view of a repair filler material in the hole of FIG. 11;
[0031] [0031]FIG. 13 is a side-sectional view of molten repair filler material and casting;
[0032] [0032]FIG. 14 is a flow chart of a process for repairing a casting having an intentional defect, such as a bumper hole, as embodied by the invention;
[0033] [0033]FIG. 15 is a side-sectional view of a defect, for example, a through crack in a casting;
[0034] [0034]FIG. 16 is a side-sectional view of a hole in the casting, as embodied by the invention;
[0035] [0035]FIG. 17 is a side-sectional view of a repair filler material in the hole of FIG. 16;
[0036] [0036]FIG. 18 is a side-sectional view of molten repair filler material and casting;
[0037] [0037]FIG. 19 is a flow chart of a process of FIGS. 15 - 18 , as embodied by the invention;
[0038] [0038]FIG. 20 is a side-sectional view of a defect, for example, a thin region formed by a bumper in a casting;
[0039] [0039]FIG. 21 is a side-sectional view of repair material on the casting, as embodied by the invention;
[0040] [0040]FIG. 22 is a side-sectional view of the repair filler material becoming molten material;
[0041] [0041]FIG. 23 is a side-sectional view of molten repair filler material and casting; and
[0042] [0042]FIG. 24 is a flow chart of a process of FIGS. 20 - 23 , as embodied by the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0043] Defects resulting from casting processes can take several distinct forms. For example, defects resulting from casting processes may include surface defects. Surface defects resulting from casting processes can include cracks, freckles, or voids which may result during re-solidification of the casting. Also, as described above, intentional defects, such as bumper holes, constitute defects.
[0044] Defects may also result from use of the cast component. For example, these defects can be cracks resulting from field use of the component. These cracks are due, at least in part to a critical combination of thermal and mechanical stresses that the components are subjected to during operation.
[0045] Cracks that result from field use often require cleaning, because the crack surfaces may have been oxidized. Oxidized crack surfaces present an undesirable surface for repair. The oxidized surface is unreliable both mechanically and metallurgically. A mechanically and metallurgically sound repair by bonding a metal in an oxidized crack will be difficult, if not impossible, due to oxides on the crack surface.
[0046] Accordingly, as embodied by the invention, it is desirable and advantageous to provide a method for repair of defects in castings, where the defects result from at least one of casting processes and use. By virtue of the repair process, as embodied by the invention, the casting will be reliably repaired, without the need for the casting to be scrapped. Therefore, as embodied by the invention, methods for repairing defects in cast products provide extended use of casting and avoid scrapping the casting.
[0047] As embodied by the invention, the repair of defects in cast products comprises a method that includes heat treating the defect area, the repair material and the casting itself, with or without repair material. The heat treating is done by an appropriate device and method, for example by at least one of electron beam welding, plate welding and other welding processes.
[0048] A repair method, as embodied by the invention, for the repair of a defect, such as bumper holes, will now be discussed with reference to FIGS. 1 - 4 and the flowchart of FIG. 5. The casting process is, for example but not limited to, an investment casting process. The cast article 1 relies upon at least one bumper 13 for casting due to the complexity of the casting 10 . Because investment casting is known in the art, an explanation of the process is omitted. Thus, the cast article 1 comprises a ceramic casting core 14 used in a casting process and a casting 10 .
[0049] If the casting process uses at least one bumper 13 , the repair method for bumper recess or hole defects comprises first locating the defect 5 , in step S 1 . Location of the defects 5 is done prior to any removal, separation, or reduction of the ceramic casting core 14 . The ceramic core 14 provides a support for filler material 25 , which will be used to repair the defect 5 , as described hereafter.
[0050] Once the defect 5 has been located, a part of a defect area 7 (dashed line in the Figures) of the cast article 1 that surrounds the bumper hole 12 is removed, in step S 2 . Next, a ceramic bumper 13 , which is used in the investment casting process to form the bumper hole 12 is removed, in step S 3 . Preferably, the removal of the ceramic bumper 13 is in the same step that removes the casting 10 at the defect area 7 . Accordingly, the removal of material forms a flat-bottomed hole 20 generally located at the defect area 7 .
[0051] A repair material 25 , alternately referred to as a filler material, is then provided in the flat-bottomed hole 20 , in step S 4 . The repair material 25 is preferably the same material of the casting 10 . Alternatively, the repair material 25 may be a material that is compatible, metallurgically and physically, with the casting 10 .
[0052] The repair material 25 is provided generally in the form of a repair material plug 26 . The repair material plug 26 preferably has a general shape approximately conforming to the shape of the flat-bottomed hole 20 . This conforming shape permits the repair material to substantially fill the entire flat-bottomed hole 20 . Alternatively, the repair material plug 26 need not approximate the shape of the flat-bottomed hole 20 , provided the volume of the repair material plug 26 is greater that the volume of the hole 20 .
[0053] The volume of the repair material plug 26 should be sufficient to completely fill the flat-bottomed hole 20 , and extend above the hole 20 top surface 21 . In other words, the volume of the filler material 25 is greater than the volume of the flat-bottomed hole 20 . This extension of the repair material plug 26 above the hole surface 21 will assure that the repair material plug 26 will completely fill the hole 20 upon melting. Further, as embodied by the invention, cooling stresses that may form during the cooling of the molten material will tend to be distributed in any excess material above the top surface 21 of the flat-bottomed hole 20 . In other words, stresses are formed away from the casting 10 .
[0054] Once the repair material plug 26 has been inserted into the flat-bottomed hole 20 , the defect area 7 is heat treated, with full penetration of the casting thickness t, in step S 5 . For example, the defect area 7 can be heated by an appropriate heating device, such as but not limited to, an electron beam welder. The heat in step S 5 is applied under predetermined conditions to bring at least a portion of surrounding material of the casting 10 and the repair material plug 26 into a molten condition 27 in FIG. 4.
[0055] The heating preferably comprises a gradual heating of the casting 10 and the repair material plug 26 . The predetermined conditions also provide a gradual cooling of the molten material 27 . The gradual heating and gradual cooling minimizes temperature gradients formed during repair. Gradual heating and cooling minimizes temperature gradients formed during repair, thus minimizing stress generation in the defect area 7 .
[0056] The predetermined conditions for heating are dependent upon several factors. These factors, include, but are not necessarily limited to: the material composition of the casting 10 ; the repair material 25 composition; the location of the defect area 7 ; the ambient environment of the cast article 1 , for example vacuum or a partial pressure of inert gaseous environment.
[0057] With the surrounding material of the casting 10 and the repair material plug 26 as molten material 27 , the retained ceramic core 14 supports the molten material 27 until it re-solidifies, at step S 6 . Therefore, the molten material 27 is kept at the defect area 7 .
[0058] Any excess material can be removed further in the repair process, step S 7 , if needed. The excess material remaining on the repaired casting surface can be removed by, for example, at least one of a machining process and a benching process. The core is then removed, by known methods, resulting in a repaired casting.
[0059] After the molten material at 27 has re-solidified in step S 6 and any excess material is removed, as needed in step S 7 , the repaired casting is inspected at the defect area 7 by an appropriate inspection device. The inspection device determines whether the repair process has successfully repaired the defect 5 . If the inspection determines that the repair process has successfully repaired the defect, the manufacturing process continues.
[0060] The cast article 1 , as embodied by the invention, can be in any form, such as one of an as-cast condition and a casting after a first solution heat treatment after initial casting.
[0061] A casting 10 is often prone to cracking during any type of localized heating operations, such as in previously attempted repair processes. To eliminate cracking, as embodied by the invention, a slow, uniform heating and cooling, reduces thermal stresses in the molten material 27 .
[0062] Heating, for example by electron beam welding, as embodied by the invention, provides a slow, uniform heating and cooling to reduce thermal stresses induced to the re-solidified material. Further predetermined parameters for heating by electron beam welding, comprise but are not limited to: 1) electron beam focus factors, such as a suitable raster pattern, for example area, line or spot patterns, a suitable amount of beam dither, and other electron beam focus variables; 2) at least partial, and alternatively, full, weld penetration, controlled by electron beam potential; 3) an appropriate casting material, such as but not limited to, a nickel base superalloy, which provides concomitant heating, holding, and cooling ramp rates; and 4) an appropriate pre-heat temperature for the cast article 1 .
[0063] If the casting 10 comprises directionally solidified and single crystal structures, the above-described repair process creates grain structure in the repaired area 7 that is substantially similar to, and very compatible with, the initial micro-structure of the casting 10 . This is especially advantageous, as it provides a structurally and metallurgically sound and reliable repair.
[0064] Inspection of the repaired part comprises any appropriate inspection device, such as but not limited to, an ultrasonic inspection device, a bright field illumination device, a fluorescent dye penetration inspection device, an x-ray inspection device and combinations of such devices.
[0065] The above described method discusses a repair of bumper holes and other through-wall defects in an investment casting. A process for surface defect repair, including but not limited to voids, surface freckles, inclusions, cracks and freckles, as embodied by the invention, will now be discussed with reference to FIGS. 6 - 8 and the flowchart of FIG. 9.
[0066] The repair of surface defects comprises initially locating the defect 52 , in step S 11 . Once the defect 52 has been located in the casting 54 , a defect repair material 56 may be provided to the defect 52 , in step S 12 .
[0067] The surface defect repair material 56 , if needed, is preferably in the form of a filler wire, elongated strand-like material or other compatibly shaped surface defect repair material. The surface defect repair material 56 is preferably formed of a composition that is the same as the composition of the casting 54 . Alternatively, as discussed above, the surface defect repair material may be formed of a composition that is compatible with, both metallurgically and physically, with the material of the casting 54 .
[0068] The surface defect repair material 56 is provided in a form of a filler wire, elongated strand-like material, or other compatible shape to approximate the shape of the defect 52 . The surface defect repair material 56 conforms to and substantially fills the volume of the surface defect 52 , while having a volume exceeding that of the defect 52 . Alternatively, the surface defect repair material 56 may not have a shape approximating the shape of surface defect 52 , as long as it has a volume greater than the volume of the surface defect. The surface defect repair material 56 can be provided as a cut piece of filler wire, an elongated strand-like material, or as a continuous feed wire, constituting a continuous feed wire repair process for surface defects. Alternatively, no additional repair material may be used.
[0069] To repair a surface defect 52 , the repair material 56 is inserted into the defect 52 , at step S 12 . Next, the defect area is heated at step S 13 by heat treating with an appropriate heating device. As discussed above, the appropriate heating device may comprise, but is not limited to, an electron beam welder. The heat is applied under predetermined heating conditions, as discussed above.
[0070] After the surface defect repair material 56 and the surrounding casting 54 are molten 58 , the molten material 58 is allowed to re-solidify in step S 14 . Any excess material is removed as needed, in step S 15 . Thereafter, the repaired casting 54 is inspected by an appropriate inspection device, as discussed above.
[0071] As embodied by the invention, repair of surface defects, such as freckles and cracks, may not require additional material to fill the defect. The defect may be comprised of a superficial irregularity in the microstructure of the casting, and not necessarily by a lack of material at the defect site. In this case, the surface defect to be repaired, such as a surface freckle is first located. The area of the surface defect is heated to make the surface defect area molten. The molten material is then re-solidified, as described above. Accordingly, a repaired surface defect, that was in the form of a surface freckle, is repaired as embodied by the invention.
[0072] A method for the repair of oxide-laden defects in castings, as embodied by the invention, such as but not limited to oxide-laden cracks, will now be discussed. The steps of the process for the repair of oxide-laden defects are substantially similar to the process of repairing surface defects, discussed above.
[0073] To repair oxide-laden defects, the defect is first located. The repair material is positioned over the oxide-laden defect, and the defect area is heated to cause the repair material and the surrounding cast material to become molten, as described above.
[0074] While molten, oxides are released from the surface of the defect. These oxides rise to the top of the molten material due to their relatively low density. With the oxides removed from the surface of the oxide-laden defect, a sound metallurgical bond and physically strong repair of the defect is achieved. Further details in the repair of oxide-laden defects, as embodied by the invention, are as discussed above, and further discussion is thus omitted.
[0075] A repair method, as embodied by the invention, for the repair of a defect, such as bumper holes, will now be discussed with reference to FIGS. 10 - 13 and the flowchart of FIG. 14. The casting process is, for example but not limited to, an investment casting process. The casting 100 relies upon bumpers, as described above, due to the complexity of the casting 100 . Because investment casting is known in the art, a detailed explanation of the process is omitted.
[0076] In this repair method, as embodied by the invention, the casting core and bumpers are removed prior to any steps of the repair. The casting core can be removed by any known methods relied upon in the art. Accordingly, the casting 100 comprises at least one bumper hole 112 and forms the article to be repaired.
[0077] The repair method for a casting 100 with a bumper hole 112 comprises first locating the defect 105 , in step S 100 . The location of the defect 105 is done after removal, separation, or reduction of the ceramic casting core.
[0078] Once the defect 105 has been located, a part of a defect area 107 (dashed line in the Figures) of the cast article 100 that surrounds the bumper hole 112 is removed, in step S 102 . Accordingly, the removal of material forms a through-hole 120 generally located at the defect area 107 .
[0079] A repair material 125 , alternately referred to as a filler material, is then provided in the through-hole 120 , in step S 104 . The repair material 125 is preferably the same material as the casting 100 . Alternatively, the repair material 125 may be a material that is compatible, metallurgically and physically, with the casting 100 .
[0080] The repair material 125 is provided generally in the form of a plug 126 . The plug 126 preferably has a shape approximately conforming to the through-hole 120 , permiting the repair material to substantially fill the entire hole volume 120 . However, the plug 126 need not approximate the shape of the through-hole 120 , as long as the volume of the plug 126 exceeds the volume of the hole 120 .
[0081] The volume of the repair plug 126 should be sufficient to completely fill the through-hole 120 and extend above and below the hole 120 top 121 and bottom 122 surfaces. In other words, the volume of the filler material 125 is greater than the volume of the through-hole 120 . This extension of the repair plug 126 above the through-hole 120 top surface 121 and bottom surface 122 will assure that the plug 126 will completely fill the through-hole 120 when melted. Any residual stresses that may be formed in the process are believed to be concentrated in the last portion of the molten material to re-solidify, for example in the areas outside of the through-hole 120 above the top surface 121 and below the bottom surface 122 . Thus, any residual stresses that may cause cracks or other such defects can be removed by further machining of the repaired area.
[0082] Once the repair material plug 126 has been inserted into the through-hole 120 , the defect area 107 is heat treated in step S 105 . However, contrary to the full-penetration heating described above, the beam does not fully penetrate the casting thickness, t. This partial-penetration heat treating, for example with an electron beam, prevents the electron beam from harming any material located behind the casting 100 . The heat in step S 105 is applied under predetermined conditions to bring at least a portion of surrounding material of the casting 100 and the repair material plug 126 into a molten condition 127 , as shown in FIG. 13.
[0083] With the surrounding material of the casting 100 and the repair material plug 126 heated to molten material 127 , the molten material is retained in the through-hole 120 by surface tension of the molten material. The principles of surface tension are well known, and a further discussion of surface tension is omitted.
[0084] The surface tension suspends the molten material 127 in the through-hole 120 within the support of the casting 100 . The electron beam used for heating in step S 105 is balanced to achieve melting of the plug 126 and the surrounding casting 100 at the defect area 107 , while not disturbing the surface tension forces that hold the molten material 127 in the through-hole 120 . Further, the electron beam strength is also balanced to maintain the suspension of the molten material 127 and avoid full penetration of the casting 100 .
[0085] The heating preferably comprises a gradual heating of the casting 100 and the repair material plug 126 . The predetermined conditions also provide a gradual cooling of the molten material 127 . The gradual heating and gradual cooling minimizes temperature gradients formed during repair. Thus, the gradual heating and cooling provides for minimized stress generation in the defect area 107 . However, the above described balancing with respect to non-full penetration, surface tension and maintaining a suspension of the molten material 127 in the through-hole 120 must be observed. Other predetermined conditions for heating are as described above. Accordingly, a further description is not provided.
[0086] The molten material 127 then re-solidifies at step S 106 . Any excess material above and below the casting 100 at the area where the through-hole 120 was located, including generated stresses, can be removed further in the repair process, in step S 107 , if needed. Excess material remaining on the repaired casting surface can be removed by, for example, at least one of a machining process and a benching process.
[0087] After the molten material at 127 has re-solidified in step S 106 and any excess material is removed, as needed in step S 107 , the repaired casting is inspected at the defect area 107 by an appropriate inspection device. The inspection device determines whether the repair process has successfully repaired the defect area 107 . If the inspection determines that the repair process has successfully repaired the defect, the manufacturing process continues.
[0088] A further repair process for non-intentional defects, as embodied by the invention, will now be discussed with reference to FIGS. 15 - 18 and the flowchart of FIG. 19. The non-intentional defects comprises defects such as cracks, both surface and through wall cracks, without bumpers.
[0089] The repair process for non-intentional defects comprises defects such as cracks, both surface and through wall cracks, without bumpers comprises first locating the defect 212 , such as a through crack as illustrated, in a casting 210 in step S 110 . Next in step S 120 , an area of the casting 210 at the defect area 207 is removed to form a hole 220 . The hole can be a through-hole extending across the casting 200 , or can be a partial hole that extends only partially through the casting 200 .
[0090] A repair material 225 , alternately referred to as a filler material, is then provided in the through-hole 220 , in step S 130 . The repair material 225 is preferably the same material of the casting 200 . Alternatively, the repair material 225 may be a material that is compatible, metallurgically and physically, with the casting 200 .
[0091] The repair material 225 is provided generally in the form of a repair material plug 226 . The repair material plug 226 preferably has a general shape approximately conforming to the shape of the through-hole 220 . This conforming shape permits the repair material to substantially fill the entire through-hole 220 . Alternatively, the repair material plug 226 need not approximate the shape of the through-hole 220 . All that is needed is the volume of the repair material plug 226 is greater that the volume of the through-hole 220 .
[0092] The volume of the repair material plug 226 should be sufficient to completely fill the through-hole 220 , and extend above the hole 220 top surface 221 and below the bottom surface 222 of the hole 220 . In other words, the volume of the filler material 225 is greater than the volume of the through-hole 220 . This extension above the through-hole 220 top surface 221 and the bottom surface 222 of the repair material plug 226 will assure that the repair material plug 226 , when melted, will completely fill the through-hole 220 .
[0093] Once the repair material plug 226 has been inserted into the through-hole 220 , the defect area 207 is heated by heat treating in step S 140 . However, contrary to the full penetration as described above, the heating is not full penetration of the casting thickness t. This non-full penetration heat treating, for example with an electron beam, prevents the electron beam from hitting and disrupting and harming anything located behind the casting 200 . The heat in step S 140 is applied under predetermined conditions to bring at least a portion of surrounding material of the casting 200 and the repair material plug 226 into a molten condition as molten material 227 in FIG. 18.
[0094] With the surrounding material of the casting 200 and the repair material plug 226 heated to molten material 227 , the molten material is retained in the through-hole 220 by the surface tension of the molten material interacting with the through-hole 220 . The principles of surface tension are well known, and a further discussion of surface tension is omitted.
[0095] The surface tension suspends the molten material 227 in the through-hole 220 within the support of the casting 200 . The electron beam parameters used for heating in step S 140 are optimized to achieve melting of the plug 126 and the surrounding casting 100 at the defect area 207 while maintaining the molten material 227 in the through-hole 220 . Further, the electron beam strength is optimized to maintain the suspension of the molten material 227 and avoid full penetration of the casting 200 .
[0096] The molten material 227 re-solidifies at step S 150 . Any excess material above and below the casting 200 at the area where the through-hole 220 was located can be removed as part of the repair process, step S 160 , if needed. Excess material remaining on the repaired casting surface can be removed by, for example, at least one of a machining process and a benching process.
[0097] After the molten material at 227 has re-solidified in step S 150 and any excess material is removed, as needed, in step S 160 , the defect area 207 of the repaired casting is inspected by an appropriate inspection device to determines whether the repair process successfully repaired the defect 212 . If the inspection determines that the repair process has successfully repaired the defect, the manufacturing process continues.
[0098] The heating preferably comprises a gradual heating of the casting 200 and the repair material plug 226 . The predetermined conditions also provide for a gradual cooling of the molten material 227 . Gradual heating and cooling minimizes temperature gradients formed during repair, thus mediating the residual stresses generated in the defect area 207 . Again, the above-described optimization with respect to partial penetration and maintaining a surface-tension governed suspension of the molten material 227 in the through-hole 220 must be observed, Other predetermined conditions for heating are as described above. Accordingly, a further description is not provided.
[0099] Another repair method, as embodied by the invention, for the repair of a defect, such as bumper holes in a casting 300 with the casting core removed, will now be discussed with reference to FIGS. 20 - 23 and the flow chart of FIG. 24. The casting process is, for example but not limited to, an investment casting process. The casting 300 relies upon bumpers for casting due to the complexity of the casting 300 . Because investment casting is known in the art, an explanation of the process is omitted.
[0100] If the casting process uses bumpers, the repair method for bumper hole defects comprises first locating the defects 305 , in step S 200 . Location of the defects 305 is accomplished after removal, separation, or reduction of the ceramic casting core (not illustrated).
[0101] Once the defect 305 has been located, a repair material 325 is positioned at the defect area 307 (dashed line in the Figures) of the cast article 300 that is proximate the bumper hole 320 , in step S 201 . The figures illustrate the repair material 325 on the non-bumper hole surface 301 of the casting 300 . However, the scope of the invention comprises the repair material 325 being located on the bumper hole surface 302 .
[0102] The repair material 325 is preferably the same material as the casting 300 . Alternatively, the repair material 325 may be another material that is metallurgically and physically compatible with the casting 300 .
[0103] The repair material 325 is provided generally in the form of a plug 326 . The plug 326 has volume greater that the volume of the bumper hole 320 . The volume of the repair material plug 326 should be sufficient to completely fill the bumper hole 320 . In other words, the volume of the filler material 325 is greater than the volume of the bumper hole 320 . This volume will assure that the repair material plug 326 , when melted, will completely fill the bumper hole 320 . Any residual stresses that may be formed in the process are believed to be concentrated in the last portion of the molten material to re-solidify, for example in the areas outside of the bumper hole and above the top surface. Thus, any residual stresses that may cause cracks or other such defects can be removed by further machining of the repaired area.
[0104] Once the repair material plug 326 has been located at the defect area 307 , the area is heat treated, in step S 203 , with partial penetration of the casting 300 , for example with an electron beam. This partial-penetration heat treatment prevents the electron beam from harming anything located behind the casting 300 . The heat in step S 203 is applied under predetermined conditions to bring at least a portion of surrounding material of the casting 300 and the repair material plug 326 into a molten condition 327 , as shown in FIG. 22.
[0105] With the surrounding material of the casting 300 and the repair material plug 326 molten 327 , the molten material is retained in the casting 300 by the surface tension of the molten material 300 . However, the molten material 327 is sufficiently fluid to permit it to flow and conform to the surfaces 301 and 302 of the casting 300 , as illustrated in FIGS. 22 and 23. The principles of surface tension are well known, and a further discussion is omitted.
[0106] The surface tension suspends the molten material 327 in the casting 300 . The electron beam used for heating in step S 203 is balanced to achieve melting of the repair material 325 and the surrounding casting 300 at the defect area 307 , while not disturbing the molten material 327 suspended in the casting 300 . Further, the electron beam strength is also balanced to maintain the suspension of the molten material 327 and avoid full penetration of the casting 300 .
[0107] The molten material 327 , after flowing in step S 204 , is re-solidified in step S 205 . The excess material remaining on the repaired casting surface can be removed by, for example, at least one of a machining process and a benching process. The core is then removed, by known methods, to result in the repaired casting.
[0108] After the molten material 327 has re-solidified in step S 205 and any excess material is removed, as needed in step S 206 , the repaired casting is inspected at the defect area 307 by an appropriate inspection device to determine whether the repair process has successfully repaired the defect 305 . If the inspection determines that the repair process has successfully repaired the defect, the manufacturing process continues.
[0109] The heating and predetermined conditions for the heating process, as embodied by the invention, are as discussed above. Therefore, a further discussion of these features of the invention is omitted.
[0110] Accordingly, the repair processes, as embodied by the invention, provides an economical, efficient repair of defects, whether intentional or non-intentional, regardless of cause. The repair methods, as embodied by the invention, enable castings to be repaired parts which would otherwise require scrapping of the part. Such repair is desirable from both economical and efficiency considerations.
[0111] While the embodiments described herein are preferred, it will be appreciated from the specification that various combinations of elements, variations or improvements therein may be made by those skilled in the art, and are within the scope of the invention. | A method of repairing a defect in a casting or cast article, where the defect comprises at least one of a manufacturing, intentional, or service-related defect. The cast article can comprise a casting core and a casting, the casting core comprising a bumper that creates a thin region, namely the defect. One method of repairing the bumper hole defect comprises locating the defect area in the cast article; removing an area of the casting at the defect area; removing an area of the casting core including the bumper at the defect area, where the removing the area of the casting at the defect area and removing an area of the casting core including the bumper at the defect area create a hole; positioning repair material in the hole; heating the defect area, the repair material and the area of the casting at the defect area to melt the repair material and area of the casting at the defect area into a molten material; and re-solidifying the molten material to form a repaired casting. Also, the method without forming the hole can be applied to repair surface defects. The invention also is directed to the repaired article formed by the methods. | 1 |
BACKGROUND OF THE INVENTION
The invention concerns a pressurized water container as it is used in connection with water fountain, pond, swimming pool or aquarium technology. Such pressurized water containers comprise at least two housing parts, between which at least one seal is arranged and which are connectable to one another in a lockable way. Water is forced through such containers under pressure and in this way, for example, filtered, supplied to a nozzle, or subjected to other similar mechanical actions. The container as well as the components arranged therein require a certain maintenance so that the container must be designed to be opened and closed again. Upon closing it is important to reinstate water seal-tightness that withstands the water pressures in operation. Conventional closure mechanisms are, for example, the connection of the housing parts by means of several clamps or toggle closures or by engaging a flange provided on both housing parts by means of a clamping ring. These closures are difficult to close properly by a single person. When using clamps or toggle closures the container parts must be pressed uniformly against one another, all damps must be closed while maintaining this pressure. A clamping ring must also be tightened and closed while both container parts are pressed against one another. When it is not possible to uniformly maintain the tension during the closing action on all container sides, canting occurs and this leads to a connection that is not seal-tight.
The invention has therefore the object to provide a pressurizable water container that can be closed in a simple way so as to be water-tight.
SUMMARY OF THE INVENTION
This object is solved according to the invention by a pressurized water container wherein the housing parts have projections and corresponding recesses that are designed such that the projections engage the recesses and, by displacement of the housing parts relative to one another in opposite directions, they are lockable on one another and releasable from one another when reversing the displacement.
By providing on the container parts projections and recesses matched to the projections which projections and recesses are arranged such that they secure the housing parts on one another when they are displaced relative to one another, the initiation of this displacement movement provides for a safe closure of the container even by a single person. Preferably, several projections and matching recesses should be provided on the housing parts and should preferably extend along the circumference of the container. A connection by means of at least three projections and recesses each that are uniformly distributed, i.e., arranged at a spacing of approximately 120 degrees relative to one another, can already provide a uniform sealing action. However by providing more than four projections and recesses, the canting tendency is further reduced and closing of the container becomes increasingly easier.
Even though it is possible to arrange the projections and recesses like a toothing alternately on a first housing part and a second housing part, it is advantageous with regard to manufacturing technology as well as with regard to simplifying operation to arrange the projections on the first housing part and the recesses on the second housing part.
The projections can effect by means of a slanted arrangement or a hook-shaped configuration a connection with the other housing part. Preferred is an embodiment in which the projections have terminal widened portions or thick portions and the recesses are over portions thereof of a tapering configuration so that the widened portions of the projections upon displacement of the housing parts relative to one another engage the recesses and in this way clamp the housing parts relative to one another.
BRIEF DESCRIPTION OF THE DRAWINGS
Further advantages and details result from the dependent claims and an embodiment of the invention illustrated in the drawings which embodiment will be described in the following. It is shown in:
FIG. 1 a fountain jet generator with pressurized water container and removed lid;
FIG. 2 a partial section in the direction II-II through the article of FIG. 1 with the lid in position;
FIG. 3 an exploded illustration of the container of FIG. 1 without lid;
FIG. 4 the elements of FIG. 3 , assembled;
FIG. 5 a detail of FIG. 4 before closing;
FIG. 6 the detail of FIG. 5 after carrying out the closing movement;
FIG. 7 a section view in the direction VII-VII of the article of FIG. 6 ; and
FIG. 8 a section view in the direction VIII-VIII of the article of FIG. 6 .
DESCRIPTION OF PREFERRED EMBODIMENTS
The invention will be explained in more detail with the aid of an embodiment in the form of a fountain jet generator that is illustrated most complete in FIG. 1 . It is comprised of a pressurized water container connected to a support 1 and has a housing comprised of several housing parts 2 , 3 , 4 , 5 . The lower housing part 2 forms substantially the water container and is filled predominantly with filter foams, not illustrated, for calming the water. Through the inlet 6 water is conveyed under pressure into the container by means of a pump, not illustrated, and exits from the container through a nozzle 7 and a water outlet 8 . The nozzle 7 is formed in a housing part 3 that closes off the area receiving the water in the upward direction which housing part will be explained in more detail later on. Above the housing part 3 further components are provided such as e.g. a turbulence generator 9 and an alignment actuator 10 . The entire housing is closed off at the top by a lid 5 . As can be seen in FIG. 3 , the housing can moreover have a receptacle 12 into which a lighting device for illuminating the water jet can be inserted.
For closing off the container in accordance with the invention, the lower housing part 2 is provided with several projections 13 , 14 that are formed by pins 13 with terminal spherical heads 14 . These projections 13 , 14 engage recesses 15 of the upper housing part 4 closing off the container. These recesses 15 have an enlarged open area 16 and lateral guides 17 adjoining them; they narrow the recesses 15 in such a way that the widened portion 14 of the spherical heads of the matching projections 13 , 14 is engaged.
When closing the container, which is realized by a sliding movement of the upper housing part 4 in the direction of arrow V in FIG. 5 into the position illustrated in FIG. 6 , the lateral flanges 17 of the recesses 15 engaging the spherical heads 14 provide a forced guiding action for the displacement movement of the housing parts 2 and 4 relative to one another. This lateral guides 17 are designed, as can be clearly seen in FIG. 8 , like an ascending ramp so that when the closing movement is carried out the upper housing part 4 will be automatically pulled closer against the lower housing part 2 . In order to be able to carry out the closing movement with as little force as possible, the lateral guides 17 , as shown in FIG. 7 , are matched in their upper area to the shape of the spherical head 14 of the projections 13 , 14 . A spherical head in the context of the invention is not to be understood exclusively as a completely spherical shape but also a shape that simply widens in the upper area 14 of the projections 13 , 14 in such a way so as to be beneficial with regard to gliding. In particular, it can also be cut off at the top as illustrated. In order to provide a certain locking action of the housing connection, the guides 17 , as shown in FIG. 8 , are designed such that in the closed position they drop off or are recessed in the end area 18 of the recesses 15 relative to the projections 13 , 14 . In this way it is prevented that the projections 13 , 14 can slide automatically back into the recesses 15 and a tactile signal is provided that the locked position has been reached.
As can be seen in particular in FIGS. 3 and 4 , the recesses 15 are shaped like a slotted hole and are arranged equidistantly, annularly and rotationally symmetrically about the central longitudinal housing axis A. The displacement movement V required for dosing the container can thus be effected simply by oppositely turning the two housing parts 2 , 4 relative to one another. At the same time, by means of the plurality of the projections 13 , 14 and recesses 15 a uniform sealing action is provided without there being the risk of canting.
When the upper housing part 4 is designed, for example, in such a way that it is closed in the upward direction with the exception of the nozzle 7 , the pressurized water container could be formed by the housing parts 2 and 4 alone in combination with a corresponding seal. However, in the illustrated embodiment between the housing parts 2 and 4 a separation element 3 is arranged as a sealing plate. The sealing plate 3 has holes 19 that match the projections 13 , 14 and through which the pins 13 of the projections 13 , 14 extend when the container is closed. The holes 19 have such a size that the spherical heads 14 of the projections 13 , 14 pass through them. Accordingly, the sealing plate 3 can be displaced only minimally relative to the lower housing part 2 , i.e., only inasmuch as the diameter of the holes 19 is greater than that of the pins 13 . By means of a projections 23 of the sealing plate 3 , as shown in FIG. 7 , a sealing ring 22 is squeezed upon closing of the container against the inner wall of the lower housing part 2 and in this way a safe sealing action is achieved. The sealing plate 3 thus contributes to a long service life of the sealing ring 22 because the sealing ring, upon closing or opening of the container, is essentially only compressed and must not absorb any shearing stress. Shearing stress is prevented in this embodiment by gliding of the housing part 4 , embodied as a closure ring, on the sealing plate 3 .
In the fountain jet generator illustrated in the Figures, the upper housing part 4 , 5 is of a two-part configuration, i.e., comprised of the closure ring 4 provided with the recesses 15 and forming a base and comprised of the lid 5 . The lid 5 has the shape of a hood and is connected to the base 4 by means of separate fastening elements. In the illustrated embodiment the fastening elements are screws, not illustrated, that can be screwed through penetrations 25 of the hood 5 into threaded sleeves 24 of the base 4 . Since this screwing action does not provide any further connection with the sealing plate 3 or the lower housing part 2 , the hood 5 and the closure ring 4 can be removed together from the housing part 2 without the fastening elements having to be released. This is, for example, beneficial when it is only necessary to exchange filter sponges arranged in a receiving space F in the lower housing part 2 .
In order to prevent accidental opening of the container by oppositely turning the housing parts 2 and 4 relative to one another, preferably a safety element 26 is provided that connects the housing part 4 , 5 with the other housing part 2 or the sealing plate 3 . In the illustrated embodiment, this securing action against opening is realized indirectly by a safety element 26 in the form of a screw that, as illustrated in FIG. 2 , connects the lid 5 to the sealing plate 3 . In this way, indirectly also the housing parts 2 and 4 are connected to one another so as to prevent relative rotation because the safety element or screw 26 is screwed through an eccentrically arranged opening 27 into a corresponding receptacle 28 . The safety element 26 as well as the receptacle 28 can be of a small size because they are provided only as an additional securing means against accidental opening while the entire pressure forces in the water container are absorbed by the force-locking and positive-locking connection by means of the projections 13 , 14 , the recesses 15 , and the sealing ring 22 .
Advantageously, the pressurized water container according to the invention can be opened and closed by a single person without operating error and enables in this connection in a simple way access to the desired container areas for inspection purposes.
The specification incorporates by reference the entire disclosure of German priority document 10 2007 014 570.7 having a filing date of Mar. 23, 2007.
While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles. | A pressurized water container for water fountains, ponds, swimming pools, and aquariums has at least two housing parts and at least one seal arranged between the at least two housing parts, wherein the at least two housing parts are connectable to one another in a lockable way. The at least two housing parts have projections and matching recesses, wherein the projections engage the recesses and, by a displacement of the at least two housing parts relative to one another in opposite directions, they are lockable on one another and releasable from one another when reversing the displacement. | 1 |
This is a division, of application Ser. No. 105,161, filed Dec. 19, 1979, now U.S. Pat. No. 4,306,065.
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to certain 2-aryl-4-substituted quinazolines, more particularly the invention is concerned with novel 2-arylquinzolines having nitrogen linkage at the 4-position, which compounds have hypotensive pharmacological activity in warm-blooded animals, pharmaceutical methods and compositions.
2. Description of the Prior Art
4-Amino-substituted quinazolines wherein the 4-substituent is a 4-(β-hydroxyethyl)-1-piperazinyl radical or a 4-methyl-1-piperazinyl radical useful as central nervous system stimulants and antidepressants have been disclosed in U.S. Pat. No. 3,470,182. The 2-position on quinazoline is unsubstituted.
4-Phenyl-substituted quinazolines having the 2-position substituted with piperidino or (4-methyl-1-piperazinyl) having analgetic and anti-allergenic activity are disclosed in U.S. Pat. No. 3,505,553.
2-Phenyl-6-hydroxy-quinazolines substituted in the 4-position by piperidino, alkylamino, morpholino and 4-methyl-1-piperazinyl radicals have been reported in Chemical Abstracts 79, 92149n, useful as bactericides.
4-Methylamino-2-(o-nitrophenyl)quinazoline has been disclosed in J. Chem. Soc. 1963, 3062-6. 4-Anilino and 4-(benzylamino)-2-phenylquinazoline have been disclosed in Tetrahedron Lett. 1973 (5) (359-360).
None of the foregoing disclosures reveal hypotensive activity for any of the prior art compounds and none disclose compounds of the present invention.
SUMMARY OF THE INVENTION
The present invention provides novel 2-aryl-4-substituted quinazolines which have important pharmacological activity as hypotensive agents in warm-blooded animals. The compounds of the invention are represented by the following structure formula: ##STR2## wherein
Q is represented by ##STR3## or --NR 3 R 4
R is selected from hydrogen, hydroxy, loweralkoxy, loweralkanolyl, phenoxy or phenoxy substituted by loweralkyl, loweralkoxy, trifluoromethyl, amino, nitro or halo,
Z is selected from ##STR4## and
p is zero or one;
R 1 is selected from loweralkyl, loweralkanolyl, 2-pyridyl, loweralkenyloxy-loweralkanolyl, loweralkynyloxy-loweralkanolyl, loweralkanyloxy-loweralkanolyl, phenoxy-loweralkanolyl and phenoxy-loweralkanolyl having phenoxy substituted by loweralkoxy, loweralkyl, nitro, amino, trifluoromethyl and halo;
R 2 is selected from hydrogen, hydroxy and loweralkyl, loweralkoxy or aryloxy;
R 3 is selected from loweralkanolyl, 4-cyanocycloalkyl-loweralkyl, phenoxy-loweralkanolyl and phenoxy-loweralkanolyl having phenoxy substituted by loweralkoxy, loweralkyl, nitro, amino, trifluoromethyl and halo;
R 4 is selected from hydrogen or loweralkyl,
X is selected from hydrogen, loweralkyl, loweralkoxy nitro, amino and halo, n is 1-3 inclusive.
Y is loweralkyl, m is 0 to 2 inclusive, and
the pharmaceutically acceptable addition salts and hydrates thereof.
The hypotensive properties of the novel compounds of the present invention were determined by observing blood pressure of unanesthetized normotensive dogs or spontaneously hypertensive rats by standard procedures. In the rat tests, indwelling arterial catheters were placed either in the caudal artery or in the abdominal aorta and drugs were administered either intravenously or intra-arterially. These indwelling catheters were used for direct measurements of blood pressure for conscious animals using a Statham pressure transducer and recorded by a Grass polygraph.
It is accordingly an object of the present invention to provide novel 2-aryl-4-substituted quinazolines which have a high degree of hypotensive activity in animals and which exhibit a low degree of undesirable side effects.
Another object is to provide a novel method for the treatment of hypertensive living animals, especially mammalian animals for the purpose of lowering blood pressure.
Additional objects will be apparent to one skilled in the art and still other objects will become apparent hereinafter.
DETAILED DESCRIPTION OF THE INVENTION
The present invention encompasses the novel 2-aryl-4-substituted quinazolines as set forth hereinabove in Formula I and the definitions therewith as compositions of matter and the utilization of these novel compounds in pharmaceutical compositions in living animals for their pharmacological effect as set forth hereinabove and below.
The term "loweralkyl" as used in the specification and claims includes straight and branched chain radicals of up to eight carbon atoms inclusive and is exemplified by such groups as methyl, ethyl, propyl, isopropyl, butyl, tertiary butyl, amyl, isoamyl, hexyl, heptyl, octyl and the like.
By "loweralkenyl" is meant hydrocarbon chains up to 8 carbons having at least one double bond.
By "loweralkynyl" is meant hydrocarbon chains up to 8 carbons having at least one triple bond.
By "loweralkoxy" or "loweralkanyloxy" is meant --O--loweralkyl.
By "loweralkenyloxy" is meant --O--loweralkenyl.
By "loweralkynyloxy" is meant --O--loweralkynyl.
By "loweralkanolyl" is meant loweralkyl substituted by one or more hydroxy groups.
By "aryloxy" in the definition of R 2 is meant an aryl radical such as phenoxy or naphthoxy, preferably phenoxy.
Suitable pharmaceutically acceptable addition salts include such salts as hydrochloride, hydrobromide, sulfate phosphate, oxalate, citrate, tartrate, malate, maleate, fumarate and the like. Such salts are prepared by reacting the base dissolved in a suitable solvent with an equivalent amount of an appropriately suitable acid which causes precipitation of the addition salt. Conversely, the free base may be obtained from a given acid salt by neutralizing the salt in a suitable solvent with an equivalent amount of sodium hydroxide which causes the free base to precipitate.
To form a dimaleate salt of a piperazine derivative, twice the equivalent amount of maleic acid is used.
The following equation represents the reaction when compounds of the invention are prepared directly from 2-phenyl-4-chloroquinazoline in one step: ##STR5## wherein Q, X and n are as defined hereinabove and QH is an appropriate primary or secondary amine and II is an appropriate 2-aryl-4-chloroquinazoline. All of the compounds may be prepared in this manner; however, it is sometimes advantageous to use alternate methods.
An alternate method particularly adaptable to preparation of compounds wherein Q is a heterocyclic amine residue involves first the reaction of compounds of Formula II with, for example, piperazine, methyl and dimethyl piperazine or 3-hydroxypyrrolidine or 3-hydroxypiperidine followed by expansion of the molecule by reaction of certain active groups R, R 1 and R 2 , ##STR6## wherein ##STR7## and X, R, R 1 , R 2 and n are as defined hereinabove. When the active group in the instances of R and R 2 is hydroxy, the chain may be expanded to an ether by reaction with an appropriate iodide. The reactive group in the instance of R 1 =hydrogen may be expanded to a 4-substituted piperazine with an appropriate halide. Preparation 1 illustrates R 1 =H and Example 8 illustrates the expansion to a 4-substituted piperazine.
When R 1 is hydrogen, conventional blocking agents such as acetyl chloride may be used to improve utilization of piperazinyl starting materials.
PREPARATION 1
4-(3,5-Dimethyl-1-piperazinyl)-2-phenylquinazoline Monohydrate
A mixture containing 12 g (0.05 mole) of 2-phenyl-4-chloroquinazoline, 5.7 g (0.05 mole) of 2,6-dimethyl-piperazine and 250 ml of methanol was stirred at room temperature for 2 hrs, then refluxed for 6 hrs. The white crystalline precipitate which formed on standing at room temperature was identified as the hydrochloride salt of 4-(3,5-dimethyl-1-piperazinyl)-2-phenyl quinazoline. The salt was neutralized with sodium hydroxide to give the free base 4-(3-5-dimethyl-1-piperazinyl)-2-phenyl quinazoline which was then recrystallized from methanol and water to obtain the title compound in yield of 7.5 g, m.p. 122°-124° C.
Analysis: Calculated for C 20 H 24 N 4 O 1 : C,71.40; H,7.19; N,16.65 Found: C,71.04; H,6.92; N,16.11.
EXAMPLE 1
4-[[(2-Phenyl)-4-quinazolinyl)amino]methyl]cyclohexane carbonitrile
A mixture containing 6 g (0.025 mole) of 2-phenyl-4-chloroquinazoline, 4 g (0.029 mole) of 4-(aminomethyl)cyclohexane carbonitrile and 150 ml isopropanol was refluxed for 2 hrs and filtered. The white crystalline solid from the filtration was recrystallized with methanol and water to give 3.3 g of the title compound, m.p. 190°-192° C.
Analysis: Calculated for C 22 H 22 N 4 : C,77.16; H,6.48; N,16.36; Found: C,76.84; H,6.45; N,16.31.
EXAMPLE 2
1-(2-Phenyl-4-quinazolinyl)-4-piperidinol
A mixture containing 6 g (0.025 mole) of 2-phenyl-4-chloroquinazoline, 3.53 g (0.035 mole) of 4-hydroxypiperidine and 100 ml of 95% ethyl alcohol was refluxed for 3 hrs. One gram of sodium hydroxide (in one ml of water) was added and the mixture was refluxed for an additional 2 hr period. The mixture was filtered and the filtrate was added to 300 ml of water. The white crystalline precipitate was separated and recrystallized with methanol and water to give 3.2 g of the title compound, m.p. 165°-167° C.
Analysis: Calculated for C 19 H 19 N 3 O: C,74.73; H,6.27; N,13.76; Found: C,74.72; H,6.31; N,13.72.
EXAMPLE 3
1-(2-Phenyl-4-quinazolinyl)-3-pyrrolidinol, Hemihydrate
A mixture containing 12 g (0.05 mole) of 2-phenyl 4-chloroquinazoline, 4.3 g (0.05 mole) of 3-hydroxy pyrrolidine and 150 ml of isopropanol was refluxed for 11/2 hrs. The resulting reaction mixture was filtered. The filtrate was adjusted to pH 10 with sodium hydroxide and concentrated under reduced pressure to dryness. The semi-solid residue was recrystallized twice with hot water, a white crystalline solid was obtained. The white crystalline solid was dissolved in aqueous solution adjusted to pH=3 with hydrochloric acid and reprecipitated by adjusting to pH=7.5 using sodium hydroxide. This white crystalline solid was filtered and recrystallized with hot water to yield 7.3 g of the title compound, m.p. 180°-182° C.
Analysis: Calculated for C 36 H 36 N 6 O 3 : C,71.98; H,6.04; N,13.99; Found: C,72.36; H,5.72; N,14.08.
EXAMPLE 4
2-Methyl-2-[(2-phenyl-4-quinazolinyl)amino]-1-propanol
A mixture containing 12 g (0.05 mole) of 2 phenyl-4-chloroquinazoline, 4.5 g (0.05 mole) of 2-amino-2-methyl-1-propanol and 150 ml of isopropanol was refluxed for 4 hrs and filtered. The reaction mixture cooled to room temperature and filtered. The filtrate was concentrated to dryness under reduced pressure. The semi-solid residue was recrystallized with water to give 2.2 g of the title compound, m.p. 136°-138° C.
Analysis: Calculated for C 18 H 19 N 3 O: C,73.70; H,6.53; N,14.32; Found: C,73.04; H,6.51; N,14.09.
EXAMPLE 5
4-(4-Hexyl-1-piperazinyl)-2-phenylquinazoline, Dihydrochloride, Dihydrate
A mixture containing 2.4 g (0.01 mole) of 2-phenyl-4-chloroquinazoline, 1.7 g (0.01 mole) of 1-n-hexyl piperazine and 150 ml of methanol was refluxed for 4 hrs. One half g of sodium hydroxide in one ml of water was added and refluxing continued for an additional 2 hr period. The oily precipitate in the reaction mixture was separated and washed with water to neutrality, dissolved in acetone and mixed with one ml of 12 N hydrochloric acid. The white crystalline solid obtained was recrystallized with acetone and methanol to give 3.2 g of the title compound, m.p. 272°-275° C.
Analysis: Calculated for C 24 H 36 N 4 O 2 Cl 2 : C,59.62; H,7.50; N,11.59; Found: C,59.76; H,6.86; N,11.74.
EXAMPLE 6
1-(2-Phenyl-4-quinazolinyl)-3-piperidinemethanol
A mixture containing 12.3 g (0.05 mole) of 2-phenyl-4-chloroquinazoline, 5.75 g (0.05 mole) 3-(hydroxymethyl) piperidine and 200 ml isopropanol was refluxed for 11/2 hrs. The resulting reaction mixture was filtered after standing at room temperature for 11/2 hrs. The white crystalline solid obtained from the filtration was recrystallized with methanol and water to give 8.0 g of the title compound, m.p. 116°-118° C.
Analysis: Calculated for C 20 H 21 N 3 O: C,75.21; H,6.63; N,13.16; Found: C,75.25; H,6.61; N,13.24.
EXAMPLE 7
4-[3-(2-Methoxyphenoxy)-1-pyrrolidinyl]-2-phenylquinazoline
To a solution containing 150 ml of isopropanol and 4.8 g (0.025 mole) of 3-o-methoxyphenoxypyrrolidine was added, with stirring, 6.15 g (0.025 mole) of 4-chloro-2-phenylquinazoline. The reaction was exothermic and the mixture refluxed for 15 min. The temperature subsided to room temperature and, after standing at room temperature for 11/2 hr, the resulting reaction mixture was filtered. The crystalline solid was recrystallized with isopropanol. Yield of product was 1.9 g, m.p. 142°-144° C.
Analysis: Calculated for C 25 H 23 N 3 O 2 : C,75.54; H,5.83; N,10.57; Found: C,75.11; H,5.90; N,10.53.
EXAMPLE 8
3-Phenyl-4-[cis-2,5-dimethyl-4-(2-pyridinyl)-1-piperazinyl]quinazoline
A mixture containing 8.4 g (0.03 mole) of 2-phenyl-4-chloroquinazoline, 6.3 g (0.0335 mole) of 1-(2-pyridyl)-cis-2,5-dimethylpiperazine and 200 ml of isopropanol was refluxed for 6 hrs. The resulting reaction mixture was filtered after cooling to room temperature. A crystalline solid was obtained. The crude product was dissolved in 3 N hydrochloric acid and extracted with ether. The aqueous acidic solution was adjusted to pH=7.5 and filtered. Yield of crystalline solid was 4.3 g, m.p. 68°-70° C.
Analysis: Calculated for C 25 H 25 N 5 : C,75.92; H,6.37; N,17.70; Found: C,75.30; H,6.33; N,17.66.
EXAMPLE 9
2-Phenyl-4-[4-(2-pyridinyl)-1-piperazinyl]quinazoline
A mixture containing 9.6 g (0.04 mole) of 2-phenyl-4-chloroquinazoline, 6.4 g. (0.04 mole) of 1-(2-pyridyl) piperazine and 250 ml of isopropanol was refluxed for 4 hrs. The resulting reaction mixture was filtered after cooling to room temperature. The crystalline solid was dissolved in 400 ml of 3 N hydrochloric acid and the aqueous acidic liquid was washed with ether. The aqueous layer was adjusted to pH=7.5 which precipitated crystalline solid. This acidification and basification were repeated once. Yield of product was 6.8 g, m.p. 164°-166° C. (air dried).
Analysis: Calculated for C 23 H 21 N 5 : C,75.19; H,5.76; N,19.06; Found: C,75.13; H,5.72; N,19.15.
EXAMPLE 10
4-(2-Phenyl-4-quinazolinyl)-1-piperazineethanol Dihydrochloride, Monohydrate
A mixture containing 6 g (0.025 mole) of 4-chloro-2-phenylquinazoline, 6 g (0.05 mole) of 1-hydroxyethylpiperazine and 250 ml of methanol was refluxed for 6 hrs. The resulting reaction mixture was cooled to room temperature and poured into 500 ml of water. The gummy precipitate was separated and washed with water to neutrality then dissolved in 150 ml of acetone. To the acetone solution was added 4 ml of concentrated hydrochloric acid. The resulting white crystalline precipitate was filtered and washed with acetone. Yield of the dihydrochloride monohydrate salt was 8 g, m.p. 247°-276° C.
Analysis: Calculated for C 20 H 26 N 4 O 2 Cl 2 : C,56.48; H,6.16; N,13.17; Found: C,56.67; H,5.73; N,13.30.
EXAMPLE 11
1-(2-Methoxyphenoxy)-3-[(2-phenyl-4-quinazolinyl)amino]-2-propanol, Monohydrate
A mixture containing 5.8 g (0.025 mole) of 1-amino-3-ortho-methoxyphenoxy 2-propanol hydrochloride, 6 g (0.025 mole) of 2-phenyl-4-chloroquinazoline, 150 ml of methanol, 1.0 g of sodium hydroxide (in one ml of water) was refluxed for 6 hrs. Another one gram of sodium hydroxide (in one ml of water) was added and refluxing was continued for 2 hrs. The resulting reaction mixture was cooled to room temperature and filtered. The gummy substance which was obtained when the filtrate was mixed with 300 ml of water was separated, washed with water, then dissolved in acetone. The acetone solution was treated with one ml of 12 N hydrochloric acid and the white crystalline precipitate was separated, dissolved in water, adjusted to pH=7.5. A white crystalline solid was obtained. This crystalline solid was recrystallized with methanol and water to give 1.5 g of the title compound, m.p. 138°-140° C.
Analysis: Calculated for C 24 H 25 N 3 O 4 : C,68.72; H,6.01; N,10.02; Found: C,69.01; H,5.55; N,10.10.
EXAMPLE 12
4-(2-Phenyl-4-quinazolinyl)-α-[(2-propenyloxy)methyl]-1-piperazineethanol
A mixture containing 4.8 g (0.02 mole) of 2-phenyl 4-chloroquinazoline, 4 g (0.02 mole) of 1-(1-allyloxy-2-hydroxy)propyl piperazine and 100 ml of isopropanol was refluxed for 4 hrs. One ml of 50% sodium hydroxide was added and refluxing continued for one hour. The resulting reaction mixture was filtered. The filtrate was concentrated to dryness under reduced pressure. The oily residue solidified on standing at room temperature and was recrystallized twice with 400 ml hot water each time. Crystalline solid weighing 6.5 g was obtained, m.p. 85°-87° C.
Analysis: Calculated for C 24 H 28 N 4 O 2 : C,71.26; H,6.98; N,13.85; Found: C,71.67; H,7.04; N,13.77.
EXAMPLE 13
α-[(2-Methoxyphenoxy)methyl]-4-(2-phenyl-4-quinazolinyl)-1-piperazinepropanol, Dihydrochloride, Hemihydrate
A mixture containing 4.8 g (0.02 mole) of 2-phenyl-4-chloro quinazoline, 5.6 g (0.02 mole) of 1-(3-hydroxy-4-ortho-methoxyphenoxy butyl)piperazine and 200 ml of methanol was refluxed for 16 hrs. One ml of 50% sodium hydroxide was added and refluxing continued for 4 hrs. The gummy substance which was obtained when the resulting reaction mixture was mixed with 300 ml of water was separated and dissolved in acetone. To the acetone solution was added 2 ml of 12 N hydrochloric acid. The resulting white crystalline precipitate was filtered off and recrystallized with acetone twice to give 3.8 g of the title compound, m.p. 215°-217° C.
Analysis: Calculated for C 58 H 70 N 8 O 7 Cl 4 : C,61.48; H,6.22; N,9.89; Found: C,61.51; H,6.11; N,9.83.
EXAMPLE 14
2,6-Dimethyl-4-(2-phenyl-4-quinazolinyl)-α-[2-propenyloxy)-methyl]-1-piperazineethanol, Hemihydrate
A mixture containing 3.18 g (0.01 mole) of 1-(2-phenyl quinazolinyl), 3.5-dimethylpiperazine, 1.14 g (0.01 mole) allyloxy glycidyl ether and 75 ml of isopropanol was refluxed overnight. The solution was concentrated to dryness under reduced pressure. The viscous oily residue was extracted with 150 ml of ether. The ether extract was concentrated to dryness. The solid residue was recrystallized with water to give 1.5 g of the title compound, m.p. 110°-112° C.
Analysis: Calculated for C 52 H 66 H 8 O 5 : C,70.72; H,7.53; N,12.69; Found: C,71.23; H,7.38; N,12.77.
EXAMPLE 15
1-(2-Ethoxyphenoxy)-3-[4-(2-phenyl-4-quinazolinyl)-1-piperazinyl]-2-propanol Dihydrochloride Monohydrate
A mixture containing 3.6 g (0.015 mole) of 4-chloro-2-phenylquinazoline, 4.2 g (0.015 mole) of 1-(o-ethoxyphenyl-2-hydroxypropyl)piperazine and 150 ml of methanol was refluxed for 16 hr. One gram of sodium hydroxide (in 1 ml of water) was added and refluxing continued for 2 hrs. The resulting reaction mixture was cooled to room temperature and added into 350 ml of water. The gummy precipitate was washed to neutrality with water and dissolved in acetone then treated with 1 ml of concentrated hydrochloric acid. White crystalline precipitate was obtained, which was recrystallized with acetone. Yield of title compound was 3.8 g, m.p. 205°-207° C.
Analysis: Calculated for C 29 H 36 N 4 O 4 Cl 2 : C,60.52; H,6.30; N,9.73; Found: C,60.74; H,6.00; N,9.78.
EXAMPLE 16
1-(4-Chloro-3-methylphenoxy)-3-[N-ethyl-N-(2-phenyl-4-quinazolinyl)amino]-2-propanol Dihydrochloride
A mixture containing 6.6 g (0.025 mole) of 1-(3-methyl-4-chloro-phenoxy)-2-hydroxypropyl-N-ethyl amine, 6 g (0.025 mole) of 4-chloro-2-phenyl-quinazoline and 50 ml of dimethyl formamide was heated at 60°-80° C. with stirring for 6 hrs. After cooling to room temperature, 2 ml of 50% NaOH was added. This basic mixture was heated for 2 hrs at 60°-80° C. The resulting reaction mixture was added into one liter of water. The gummy precipitate was separated, dissolved in acetone, and dried over sodium sulfate. The acetone solution was treated with ethereal hydrogen chloride and the dihydrochloride acid salt was separated and recrystallized with acetone. Yield was 4.5 g, m.p. 90°-92° C.
Analysis: Calculated for C 26 H 28 N 3 O 2 Cl 3 : C,59.95; H,5.41; N,8.07; Found: C,60.44; H,5.29; N,8.12.
EXAMPLE 17
1-(3,5-Dimethylphenoxy)-3-[(2-phenylquinazolin-4-yl)amino]-2-propanol
A mixture of 12 g (0.05 mole) of 4-chloro-2-phenylquinazoline, 10.0 g (0.05 mole) of 1-[(3,5-dimethylphenoxy)-3-amino]-2-propanol and 250 ml of dimethylformamide was heated with stirring for 18 hrs at 75°-80° C. 15 ml of 6 N sodium hydroxide was added followed by addition of 600 ml of water. The solid which precipitated was separated by filtration and washed with water to neutrality of the wash. The filter cake was triturated with acetone and petroleum ether. The semi-solid was separated by decantation and allowed to stand in low boiling petroleum ether at room temperature until it solidified and was recrystallized from acetone and diethyl ether. The product which weighed 8.2 g melted at 170°-172° C.
Analysis: Calculated for C 25 H 25 N 3 O 2 : C,75.16; H,6.31; N,10.52; Found: C,74.85; H,6.29; N,10.52.
EXAMPLE 18
1-Phenoxy-3-[(2-phenyl-4-quinazolin-4-yl)amino]-2-propanol
A mixture of 2.4 g (0.01 mole) of 4-chloro-2-phenylquinazoline, 1.65 g (0.01 mole) of 1-phenoxy-3-amino-2-propanol, 100 ml of dimethylformamide and 0.04 g (0.01 mole) of sodium hydroxide was heated with stirring at 75° C. For 6 hrs, then cooled to room temperature. The mixture was poured into 1 liter of water which resulted in precipitation of white crystals. This latter step was exothermic. The solid was filtered off and recrystallized with acetone and ether. The weight of product was 2.1 g, m.p.
Analysis: Calculated for C 23 H 21 N 3 O 2 : C,74.37; H,5.70; N,11.31; Found: C,74.53; H,5.40; N,11.61.
EXAMPLE 19
4-[4-(Naphthoxy)piperidinyl]-2-phenylquinazoline
Equimolar quantities of 4-(4-hydroxypiperidinyl)-2-phenylquinazoline, sodium hydride and 1-fluoronaphthalene are heated in dimethylformamide to prepare the title compound.
EXAMPLE 20
4-(4-Phenoxypiperidinyl)-2-phenylquinazoline
Equimolar quantities of 4-(4-hydroxypiperidinyl-2-phenylquinazoline, sodium hydride, and fluorobenzene are heated in dimethylformamide to prepare the title compound.
EXAMPLE 21
4-(4-Ethoxypiperidine)-2-phenylquinazoline
Equimolar amounts of 4-(4-hydroxypiperidinyl)-2-phenylquinazoline, sodium hydride, and ethyl fluoride are reacted in dimethylformamide to prepare the title compound.
EXAMPLE 22
4-(3-Butoxypiperidinyl)-2-phenylquinazoline
Equimolar amounts of 4-(3-hydroxypiperidinyl-2-phenylquinazoline and soda amide are mixed in dimethylformamide and reacted with butyl chloride to prepare the title compound.
EXAMPLE 23
4-(2-Phenyl-4-quinazolinyl)-α-[(2-propargyloxy)methyl]-1-piperazineethanol
Utilizing the procedure of Example 12 but substituting an equimolar amount of 1-(1-propargyloxy-2-hydroxy)propyl piperazine for 1-(1-allyloxy-2-hydroxy)propyl piperazine, the title compound is obtained.
EXAMPLE 24
4-(2-Phenyl-4-quinazolinyl)-α-[(propyloxy)methyl]-1-piperazinethanol
The title compound is obtained by hydrogenating over Raney nickel 4-(2-phenyl-4-quinazolinyl)-α-[(2-propargyloxy)methyl]-1-piperazineethanol.
FORMULATION AND ADMINISTRATION
Useful compositions containing at least one of the compounds according to the invention in association with a pharmaceutical carrier or excipient may be prepared in accordance with conventional technology and procedures. Thus, the compounds may be presented in a form suitable for oral or parenteral administration. For example, compositions for oral administration can be solid of liquid and can take the form of capsules, tablets, coated tablets and suspensions, such compositions comprising carriers or excipients conveniently used in the pharmaceutical art. Suitable tableting excipients include lactose, potato, and maize starches, talc, gelatin, and stearic, and silicic acids, magnesium stearate, and polyvinyl pyrrolidone.
For parenteral administration the carrier or excipient may be a sterile, parenterally acceptable liquid; e.g., water or a parenterally acceptable oil; e.g., arachis oil contained in ampules.
Advantageously, the compositions may be formulated as dosage units, each unit being adapted to supply a fixed dose of active ingredients. Tablets, capsules, coated tablets and ampules are examples of preferred dosage unit forms according to the invention. Each dosage unit adapted for oral administration can conveniently contain 5 to 250 mg and preferably 20 to 200 mg of the active ingredient, whereas each dosage unit adapted for intramuscular administration can conveniently contain 5 to 100 mg and preferably 10 to 75 mg of the active ingredient. Daily oral dosages of 10 to 500 mg are anticipated, depending on the severity of the condition being treated and size of the host.
It is only necessary that the active ingredient constitute an effective amount; i.e., such that a suitable effective dosage will be obtained consistent with the dosage form employed. The exact individual dosages as well as daily dosages will, of course, be determined according to standard medical principles under the direction of a physician or veterinarian.
The following formulations are representative for all of the pharmacologically active compounds of the invention.
1. Capsules--capsules of 5, 25 and 50 mg of active ingredient per capsule are prepared. With the higher amounts of active ingredient, reduction may be made in the amount of lactose.
______________________________________Typical blend for encapsulation Per Capsule, mg.______________________________________Active ingredient 5.0Lactose 296.7Starch 129.0Magnesium stearate 4.3Total 435.0 mg.______________________________________
2. Tablets--A typical formulation for a tablet containing 5 mg of active ingredient per tablet follows. The formulation may be used for other strengths of active ingredient by adjustment of weight of dicalcium phosphate.
______________________________________ Per Tablet, mg.______________________________________1. Active ingredient 5.02. Corn starch 13.63. Corn starch (paste) 3.44. Lactose 79.25. Dicalcium phosphate 68.26. Calcium stearate 0.9Total 170.3 mg.______________________________________
Uniformly blend 1, 2, 4 and 5. Prepare 3 as a ten percent paste in water. Granulate the blend with starch paste and pass the wet mass through an eight-mesh screen. The wet granulation is dried and sized through a twelve-mesh screen. The dried granules are blended with the calcium stearate and compressed.
Additional tablet formulations preferably contain a higher dosage of the active ingredient and are as follows:
______________________________________50 mg. TabletIngredients Per Tablet, mg.______________________________________Active ingredient 50.0Lactose 90.0Milo starch 20.0Corn starch 38.0Calcium stearate 2.0Total 200.0 mg.______________________________________
Uniformly blend the active ingredient, lactose, starches, and dicalcium phosphate when present. The blend is then granulated using water as a granulating medium. The wet granules are passed through an eight-mesh screen and dried at 140°-160° F. overnight. The dried granules are passed through a ten-mesh screen, blended with the proper amount of calcium stearate, and the lubricated granules then converted into tablets on a suitable tablet press.
3.
______________________________________Injectable - 2% sterile solution Per cc______________________________________Active ingredient 20 mg.Preservative, e.g., chlorobutanol 0.5% weight/volumeWater for injection q.s.______________________________________
Prepare solution, clarify by filtration, fill into vials, seal, and autoclave.
Various modifications in the compounds, compositions and methods of the invention will be apparent to one skilled in the art and may be made without departing from the spirit or scope thereof, and it is therefore to be understood that the invention is to be limited only by the scope of the appended claims. | Novel hypotensive agents are disclosed which are quinazolines substituted in the 2 and 4 position having the general formula: ##STR1## wherein Q is a secondary amine radical illustrated by loweralkanolylamino or a tertiary amine radical such as pyrrolidinyl, piperidinyl or piperazinyl, any of which may be substituted by various groups such as loweralkanolyl. | 2 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to locomotive compressor systems and, more particular, to a system for controlling locomotive compressors in a consist.
[0003] 2. Description of the Related Art
[0004] In heavy haul freight train operations, there are frequently multiple locomotives at the head end of the train, all of which are providing tractive effort to move the train under lead control from the front-most locomotive. The locomotives are typically interconnected into multiple unit (MU) system by four air pipes, consisting of the brake pipe, 20-Pipe, 13-Pipe, and MR Pipe (main reservoir) and a standard “27 Pin” jumper cable. This combination allows the driver in the lead locomotive to drive the trailing locomotives as slaves with MU control of both propulsion and braking.
[0005] In an MU configuration, the main reservoirs on each of the locomotives are interconnected via the MR pipe end hose, making the combined MR volume available to the locomotive consist. Each locomotive also includes an air compressor that is used to pressurize the main reservoirs. In addition, the 27 pin train line includes a train line for MU compressor control (usually train line #22). This allows the compressor governor on the lead locomotive to simultaneously start and stop the compressors on all of the locomotives, resulting in very rapid filling of the interconnected MR system. In addition, the MU operation of the compressors assures uninterrupted, adequate air supply even if the compressor on the lead locomotive fails.
[0006] While the rapid filling of the MR system is desirable if all the MRs are at a low state of charge, or if the train brake system is discharged, because in these conditions the higher total air capacity of multiple compressors can be fully utilized. However, most of the time, the air system on the locomotives and train brakes are charged, and the air compressor is cycling between the compressor governor upper and lower control limits, typically between 120 psi and 140 psi. As a result, the full capacity of the compressors in the MU is generally not needed.
[0007] All of the air flow into the train brake pipe is controlled by the air brake system on the lead locomotive. The locomotive air brake system includes a nominally 19/64″ diameter choke restricting the flow between the outlet of MR2 and the inlet of the brake pipe pressure control circuit. Brake pipe pressure is typically fully charged at 90 psi. A full service brake pipe reduction is typically 26 psi, which corresponds to a 64 psi brake pipe pressure. To release the train brakes, the brake pipe is recharged to 90 psi. Because the brake pipe on the train is the length of the train, often in excess of 6000 feet, and due to effect of friction in the pipe, the brake pipe in the front of the train charges well before the brake pipe in the rear of the train. As a result, the brake pipe regulating device (brake pipe relay) in the locomotive brake system begins to throttle the air flow based on the brake pipe pressure at the head of the train before the brake pipe in the train is fully charged. The net combination of the low head pressure at recharge, which is 120 to 140 psi MR pressure flowing into a 64 to 90 psi brake pipe, the 19/64″ charging choke, and throttling of the brake pipe relay means that the rate of required air flow is much less than the air flow capacity of the compressor on just one locomotive.
[0008] In a MU consist, the combined air flow capacity from the compressors on each of the locomotives is thus much greater than required and, as a result, the compressor duty cycle is very short. For example, in some cases the MR recharge from 120 psi to 140 psi may take less than 30 seconds. This is undesirable for several reasons. First, the compressor start includes high inrush current, high accelerations, and high torque on the components, all of which are ultimately damaging to the compressor. Second, because the compressor runs for so short a time, it is not able to achieve optimum, stable operating temperature. As a result, there is an accelerated wear of cold parts due to transient thermal expansion issues and the cold compressor is more prone to accumulation of condensed water from the product air. Finally, in addition to issues of corrosion, the accumulation of liquid water can freeze in winter operation, thereby causing blockage of the compressor after cooler and discharge lines.
[0009] Preferably, the compressor has a longer duty cycle, so that the compressor and related components are heated due to the heat of compression to more or less the same temperature as the discharged air. The normal operating temperature of the compressor results in much less condensation in the compressor system, and enough heat in the after cooler and discharge lines to prevent any liquid water from freezing in those critical locations. Thus, while synchronous control of all the compressors in the locomotive consist might be an advantage during dry charge, or in the event of a failure of the compressor on the lead locomotive, synchronous control is clearly detrimental to compressor life and problematic during cold weather operation because the compressor duty cycle is too short.
[0010] In some circumstances a lead locomotive in a consist could be set up to allow for independent compressor control, so the pressure governor on each locomotive turns that compressor on and off independently. This control scheme addresses the issue of too much charge capacity because all the main reservoirs are connected by the MR pipe and therefore the MR pressure on each locomotive is nominally the same and because there is a natural tolerance in the pressure governor settings on each locomotive compressor control. However, in this scheme, one compressor in the locomotive consist will turn on at a higher pressure than the other compressors in the consist due to tolerance variations of the pressure governors and will provide all of the air for the train and, as a result, the compressor utilization and compressor maintenance demand is unbalanced. Typically compressor maintenance is done on a planned, periodic schedule, with certain maintenance actions occurring at regular calendar intervals. Thus, the compressors subject to this control scheme will have done more work during the maintenance interval than others, so some compressors will be maintained too late and some serviced earlier than needed.
BRIEF SUMMARY OF THE INVENTION
[0011] The present invention comprises a system for controlling multiple air compressors in a locomotive consist, where the air compressor of each locomotive is associated with a networked controller that can send or receive commands related to the operation of the associated compressor. One predetermined controller is programmed issue commands to the other controllers so that each compressor is operated more efficiently. For example, each compressor may be sequentially enabled for refilling to MR system each time it needs refilling. The lead controller may also monitor the total utilization of the other compressors since a predetermined point in time or use so that the lead controller can implement a schedule of compressor usage that maximizes utilization of each compressor, thereby ensuring that each compressor is fully utilized during its scheduled maintenance period. The lead controller can also be coupled to thermometers or other sensors to control compressor usage to avoid freezing or other temperature related issues.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
[0012] The present invention will be more fully understood and appreciated by reading the following Detailed Description in conjunction with the accompanying drawings, in which:
[0013] FIG. 1 is a schematic of a multiple unit consist having a compressor control system according to the present invention;
[0014] FIG. 2 is a schematic of a compressor control system for each locomotive in a consist according to the present invention;
[0015] FIG. 3 is a schematic of a networked compressor control system according to the present invention;
[0016] FIG. 4 is a flowchart of compressor control according to the present invention; and
[0017] FIG. 5 is a flowchart of compressor system control according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0018] Referring now to the drawings, wherein like reference numerals refer to like parts throughout, there is seen in FIG. 1 , a smart, distributed locomotive compressor control system 10 that optimizes compressor life, cold weather operation, and balances utilization for maintenance optimization. System 10 interconnects the compressor 12 of each locomotive 14 in a multiple unit consist. In a multiple unit consist, one locomotive 14 may be designed as a lead locomotive 14 a , while subsequent locomotives 14 b through 14 n act as slaves. Although FIG. 1 represents lead locomotive 14 a at the head of the consist, locomotive 14 designated to act as lead locomotive 14 a could be located in any position along the consist.
[0019] As seen in FIG. 2 , system 10 is a series of individual locomotive control systems, each of which has an individual controller 16 associated with each compressor 12 of each locomotive 14 in a consist. Controller 16 is networked to other locomotives in the train consist via an interface 18 that connects controller 14 to a network 20 spanning the consist. Network 20 can comprise a wireless network, such as IEEE 802.11 or cellular 3G or 4G network, or a wired network, such as Ethernet or IEEE 802.5, or even a custom network employing a spare wire in the existing 27 pin train lines used for intra-train communications. Preferably, interface 18 includes a power line carrier network signal that is overlaid on the existing 27 pin train line compressor control wire, which is typically wire number 22 .
[0020] Controller 16 may monitor the rate of pressure increase in the MR system while compressor 12 is operating using a sensor 22 coupled to the MR system, such as a first main reservoir 28 . Main reservoir 28 may be connected to the main reservoir pipe 36 of the locomotive. First main reservoir 28 may also be connected via a check valve 30 to a second main reservoir 32 . Second main reservoir 32 may be connected to the braking system 34 , which is also connected to the brake pipe 40 . A power source 44 may be coupled to system 10 via switch 42 that operates in response to pressure in reservoir 28 .
[0021] System 10 may also be configured so that each controller 16 includes a monitoring module 24 that tracks the total utilization of its corresponding compressor 12 since a predetermined point in time or use, such as the last overhaul or major maintenance. Monitoring module 24 may thus report usage information to lead controller 16 , which may then establish and implement a schedule of compressor usage that preferentially commands usage of compressors in the consist that have the lowest accumulated utilization. System 10 may be further optimized by adding a real-time clock to each controller 16 and comparing accumulated compressor utilization with the time remaining until the next scheduled maintenance (or time since last maintenance), so that system 10 can target compressor usage to achieve 100 percent utilization of each compressor 12 by the end of the scheduled maintenance interval. For example, a compressor having 75 percent accumulated utilization that is 95 percent of the way through its maintenance interval would be used preferentially over a compressor having 10 percent utilization that is only 10 percent of the way through its maintenance interval. The addition of a temperature sensor 26 to system 10 , will further allow system 10 to manage compressor temperatures and avoid related issues. For example, the compressor control scheme could preferentially operate only one compressor in the consist to optimize the compressor temperature during use of the compressor when the ambient temperature is below freezing.
[0022] As seen in FIG. 3 , system 10 includes any number of individual locomotives, each of which includes a compressor control system as seen in FIG. 2 . As a result, a designated lead controller 16 a of a lead locomotive 14 a can asynchronously control each of the compressors on the remaining locomotives 14 b through 14 n in the consist to optimize charge rate, compressor temperature, and balance compressor utilization. Corresponding elements in the individual system of each locomotive, with three chosen for illustrative purposes, are indicated using sub-numerals (a, b, c).
[0023] In order to avoid maintenance interval issues, system 10 may be programmed to manage compressor utilization in several different ways. For example, under control of lead compressor controller 16 a , the refilling of the main reservoir system may be done by sequentially enabling each compressor 12 b through 12 n in the consist. The first time the MR system in the consist needs to be refilled, compressor 12 a on the first locomotive is utilized. The next time, compressor 12 b on the second locomotive is sent the command to refill the MR system, with system 10 sequentially cycling through each of the remaining compressors 12 n . In this way, all of compressors 12 a through 12 n in the locomotive consist will undergo the same amount of utilization and have an optimized duty cycle.
[0024] As seen in FIG. 4 , system 10 may be programmed to preferentially use the compressors having the lowest usage time. The first step involves an identification of all compressors in the consist 50 . Next, a utilization factor is calculated for each compressor in the consist 52 based on an assumption of total allowed usage and actual usage. For example, an assumption of an eight year useful life between overhauls and 1500 hours of powered use per year would result in a 12,000 hour useful life. It should be recognized that eight years and 1500 hours are exemplary variables and other values could be used by system 10 . Once a utilization factor is calculated for each compressor 52 , the compressors may be ranked according utilization 54 , such as from lowest to highest utilization. When a compressor ON signal is required 56, such as when the primary main reservoir is equal to or below about 125 psi, a command may be sent to the appropriate compressors 58 using the utilization factor rankings. When a check 60 determines that the primary main reservoir is equal to or above about 145 psi, all compressors may be turned off 62 and the usage hours for each compressor updated accordingly 64 .
[0025] In the event of demand for high air flow, such as during a dry charge of the braking system of train, controller 16 a of lead locomotive 14 a can monitor the rate of pressure increase in the MR system while compressor 12 a is operating using a sensor 22 a coupled to the MR system. Sensor 22 a can detect the high air flow demand based on the low rate of pressure increase in a reservoir 28 a of MR system. In this state, controller 16 a of lead compressor 12 a can send a command via interface 18 a to slave compressors 12 b through 12 n on network 20 to turn on their corresponding compressors 12 b though 12 n until the air demand is satisfied. Likewise, using the same methodology, controller 16 a of lead compressor 12 a can send a command via network 20 that instructs one or more of compressors 12 b though 12 n to shut off when the rate of MR pressure increase is too fast or desired amount has been achieved. As seen in FIG. 5 , the first step such an approach is to determine that the pressure in the primary main reservoir has fallen below a threshold 70 , such as 125 psi. The control compressor, such compressor 12 a , may then be turned ON 72 . A check is made 74 to determine whether the pressure remains below a second, lower threshold, such as 120 psi, which may indicate the need for additional compressors to be turned on due to extremely low pressure. If check 74 determines that the pressure is below the second threshold, a rate of recharging check 76 is made to determine whether rate of increase of pressure is above a predetermined rate. If not, a command is sent 78 to turn on an additional compressor, such as compressor 12 n . If check 74 determines that the pressure is not below the second threshold, however, there is no need for additional compressors to be turned on and a check 80 is made to determine whether the primary main reservoir has been adequately re-pressurized. If so, all compressors are turned OFF 82 . | A system for controlling locomotive compressors in a multiple locomotive consist to optimize compressor life, cold weather operation, and maintenance schedules. Each compressor is associated with a controller than can communicate via an interface to a network with the corresponding controllers of the other compressors that are also interfaced to the network. A lead compressor controller may then issue commands to the other compressor controller to more efficiently restore pressure to the system, to implement improved usage schedules, or to manage maintenance intervals to maximize usage of each compressor during periodic maintenance intervals. | 1 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of application Ser. No. 14/103,599, filed Dec. 11, 2013, and claims the benefit of provisional application Ser. No. 61/902,283 filed Nov. 10, 2013, which is incorporated by reference here including its Introduction and other matter not expressly set forth here. The contents of U.S. Patent Application Publication No. 2013/0212642 and Applicant's co-pending U.S. patent application Ser. No. 13/829,826 are also incorporated here by reference, in particular their disclosure of a Resilient Device Authentication System, with which suitable embodiments of the system described herein can be used.
FIELD OF THE INVENTION
[0002] This disclosure relates generally to hardware verification, and in particular but not exclusively, to binding authentication to protect against tampering and subversion by substitution.
BACKGROUND OF THE INVENTION
[0003] The unique properties of PUFs provide several advantages over traditional public key infrastructure (PKI) constructions. In general, PUFs provide two core properties: tamper detection for a larger circuit, and to act as a noisy random oracle. The first property follows from the physical design of the PUF itself. As the PUF relies on unclonable hardware tolerances (e.g. wire delays, resistance, etc.), any modification to either the PUF or the attached integrated circuit will irreversibly alter the PUF's mapping from challenges to responses. The second property is assumed in ideal theoretical models, where PUFs are treated as oracles that provide (noisy) responses to challenges, where the mapping between challenges and responses cannot be modeled or duplicated in hardware. Rührmair et al. (“Modeling attacks on physical unclonable functions,” Proceedings of the 17 th ACM conference on Computer and Corrnmunications Security , CCS'10, pages 237-249, New York, 2010, ACM (“Rührmair I”)) have refuted the claim of modeling robustness, and propose a hardware construction resilient to such attacks (Rührmair et al., “Applications of high-capacity crossbar memories in cryptography,” IEEE Trans. Nanotechnology . 10(3):489-498, May 2011 (“Rührmair II”)). Thus, theoretical constructions assuming that PUFs cannot be modeled remain interesting, as existing PUF hardware can be replaced with Rührmair et al.'s (Rührmair II) proposed design.
[0004] Literature on physically unclonable functions (PUFs) evaluates the properties of PUF hardware design (e.g., Gassend et al., “Silicon physical random functions,” Proceedings of the 9 th ACM conference on Computer and Communications Security , CCS'02, pages 148-160, New York, 2002, ACM.; Katzenbeisser et al., “PUFs: Myth, fact or busted?A security evaluation of physically unclonable functions (PUFs) cast in Silicon,” CHES , pages 283-301, Springer, 2012; Ravikanth, “Physical One-Way Functions,” Ph.D. Thesis, 2001; Rührmair II; Suh et al., “Physical Unclonable Functions for Device Authentication and Secret Key Generation,” Proceedings of the 44 th Annual Design Automation Conference ,” DAC'07, pages 9-14, New York, 2007, ACM; Yu et al., “Recombination of Physical Unclonable Functions,” GOMACTech, 2010 (“Yu I”)), provides formal theoretical models of PUF properties, and designs protocols around those definitions (cf. Armknecht et al., “A formalization of the security features of physical functions,” Proceedings of the 2011 IEEE Symposium on Security and Privacy , SP'11, pages 397-412, Washington, D.C., 2011; Brzuska et al., “Physically uncloneable functions in the universal composition framework,” Advances in Cryptology - CRYPTO 2011-31 st Annual Cryptology Conference , vol. 6841 of Lecture Notes in Computer Science , page 51. Springer, 2011; Frikken et al., “Robust authentication using physically unclonable functions,” Information Security , vol. 5735 of Lecture Notes in Computer Science , pages 262-277, Springer Berlin Heidelberg, 2009; Handschuh et al., “Hardware intrinsic security from physically unclonable functions,” Towards Hardware - Intrinsic Security , Information Security and Cryptography, pages 39-53, Springer Berlin Heidelberg, 2010; Kirkpatrick et al., “PUF ROKs: A hardware approach to read-once keys,” Proceedings of the 6 th ACM Symposium on Information, Computer and Communications Security , ASIACCS'11, pages 155-164, New York, 2011, ACM; Paral et al., “Reliable and efficient PUF-based key generation using pattern matching,” Hardware - Oriented Security and Trust ( HOST ), 2011 IEEE International Symposium , pages 128-133. June 2011; Rührmair et al., “PUFs in Security Protocols: Attack Models and Security Evaluations,” 2013 IEEE Symposium on Security and Privacy , pages 286-300, 2013 (“Rührmair III”); van Dijk et al., “Physical Unclonable Functions in Cryptographic Protocols: Security Proofs and Impossibility Results,” Cryptology ePrint Archive , Report 2012/228, 2012; Wu et al., “On foundation and construction of physical unclonable functions,” Cryptology ePrint Archive , Report 2010/171, 2010; Yu et al., “Lightweight and Secure PUF Key Storage using limits of Machine Learning,” Proceedings of the 13 th International Conference on Cryptographic Hardware and Embedded Systems , CHES'11, pages 358-373, Berlin, Heidelberg, 2011, Springer-Verlag (“Yu II”)).
[0005] Ravikanth introduced the notion of physical one-way functions in his Ph.D. dissertation. The physical construction is based on optics, using the speckle pattern of a laser fired through a semi-transparent gel to construct an unclonable and one-way function. This seminal work led to more realistic constructions of physically unclonable functions (PUFs) that did not rely on precise mechanical alignment and measurements.
[0006] Gassend et al. introduce the notion of PUFs constructed through integrated circuits. This work improves upon the original physical one-way function construction using optics by Ravikanth by removing the precise requirements necessary for mechanical alignment and output measurement. By implementing PUFs in integrated circuits, the hardware is widely available, and easy to integrate into existing systems.
[0007] Suh et al. introduced the ring oscillator construction of a PUF, which has many desirable properties. Specifically, the ring oscillator design is easy to implement in hardware, robust, and unpredictable. The authors demonstrate that ring oscillator constructions exhibit 46% inter-chip variation, yet have only 0.5% intra-chip variation.
[0008] Rührmair et al. describe a candidate direction to alleviate the problems with existing PUF constructions caused by machine learning demonstrated in Rührmair I. They introduce the notion of a super high information content (SHIC) PUF. A SHIC-PUF contains a large amount of information (e.g. 10 10 bits) while having a self-imposed slow readout rate that is not circumventable by construction. Thus, if an adversary attempts to acquire the full challenge-response pair set, the time required to achieve this would exceed the lifetime of the device. Using lithographic crossbar memory, a small PUF would require at least three years of continuous reading to fully model. As nanotechnology develops, the promise of a nonlithographic crossbar (≈10-nm) would require decades to fully model. Thus, the security of the SHIC-PUF is independent of the computational abilities of the adversary and inherently linked to the physical construction. Further, the crossbar can be used as an overlay PUF, which protects the underlying circuitry.
[0009] Yu I describe PUF constructions that treat the unique hardware characteristics of devices as genetic material. Similar to genetic recombination, these properties may be recombined to produce output with different characteristics than the original material. In the authors' construction, a PUF may be altered to provide NIST certifiable random output, an exponential challenge space and real-valued outputs. True random output is a necessary characteristic for use in cryptographically strong authentication protocols. The real valued output facilitates soft decision error correction, where both the signal and strength are reported (Yu et al., “Secure and Robust Error Correction for Physical Unclonable Functions,” IEEE Des. Test , 27 (1):48-65, January 2010, (“Yu III”)). Finally, the authors also demonstrate how to construct a multi-modal PUF, with separate generation and authentication modes.
[0010] Katzenbeisser et al. evaluate the assumed properties of various PUF constructions, finding that many lack essential characteristics of an ideal PUF. The arbiter, ring oscillator, SRAM, flip-flop and latch PUF constructions are compared for robustness and unpredictability in varying environmental conditions. While all PUF constructions are acceptably robust, the arbiter PUF has low entropy while flip-flop and latch PUFs are heavily affected by temperature fluctuations. A drawback for ring oscillators is low min-entropy, while SRAM lacks an exponential input space. However, both ring oscillator and SRAM designs more closely approximate an ideal PUF.
[0011] Next, we review the literature on applying PUFs to cryptographic protocols, and developing formal models to evaluate the security of PUF-dependent protocols.
[0012] Handschuh et al. give a high level description of how PUFs can be applied to anti-counterfeit and intellectual property domains. The authors outline the shortcomings of existing property protection approaches, which is primarily key storage design. By employing PUFs, the secret key is no longer duplicable, as PUFs are by design unclonable.
[0013] Rührmair I describe attacks on a variety of PUF constructions, including arbiter and ring oscillator designs. The modeling attacks require only a linear number of challenge response pairs with respect to the structural parameters of the PUF constructions. In constructions where the attacks require superpolynomially many challenge response pairs, the underlying construction grows superpolynomially in the number of components. Thus, the underlying construction becomes infeasible to build, and the designer and adversary face the same asymptotic difficulty. The attacks presented are sufficient to break most PUF constructions in production, and demonstrate that other approaches seem to meet with exponential increases in complexity for both defender and adversary.
[0014] Wu et al. demonstrate that a PUF with l-bit input, m-bit output and n components does not implement a random function when
[0000]
n
<
m2
c
[0000] for some constant c. That is, the size of a random function family must be equal to the size of the output domain. Letting be a function family of PUFs and be the output domain, we have that =2 m2 l . However, when
[0000]
ℱ
=
n
<
m
2
c
,
[0000] then
[0000]
ℱ
=
2
2
m
2
c
<
2
m
2
=
.
[0000] This information theoretic bound establishes PUFs with
[0000]
n
<
m
2
c
[0000] components as a pseudorandom function family. In order for such PUF families to implement a proper psuedorandom family, confusion and diffusion of the input are necessary. The authors show how to construct a physically unclonable pseudorandom permutation by using a PUF to generate the key for a block cipher. Finally, the authors construct a secure helper data algorithm called the majority voting dark bit for error correction that is more efficient than standard soft decision error correcting codes.
[0015] Yu II describe a machine learning based rationale for security by considering an adversary's advantage against PUFs with a given classification error. By assuming that a PUF with k bits in the parameter requires at least k challenge-response pairs to gain a classification advantage, the authors conclude that a classification error rate of 0.5 is equivalent to security. Technically, the authors should specify that this result would only apply to PUFs with a single bit output. By removing the assumption that the output of a PUF is independent and identically distributed (i.i.d.), the complexity of the PUF can be reduced in addition to reducing the complexity of the error correcting code.
[0016] Kirkpatrick et al. describe how to use PUFs to generate read-once keys, where upon use the key is immediately destroyed and further use is impossible. Such a construction would facilitate one-time programs as proposed by Goldwasser et al. (“One-time Programs.” Proceedings of the 28 th Annual Conference on Cryptology: Advances in Cryptology , CRYPTO 2008, pages 39-56, Berlin, Heidelberg, 2008, Springer-Verlag). The PUF-ROK construction requires integration with a register that stores an initial seed value, which is the effective security parameter. The PUF and register are in a feedback loop, so upon reading the output of the PUF the initial key is permanently destroyed. The authors also describe how to allow decryption with read-once keys in an arbitrary order. Thus, an effective k-read key can be constructed.
[0017] Armknecht et al. give formal security definitions for the desirable properties of a PUF. Existing models did not allow the broad range of PUF constructions to be accurately modeled, for example by requiring the PUF to act as a physical one-way function. With the introduction of PUFs that output only a single bit, inversion becomes trivial. The authors' PUF model requires robustness, physical unclonability and unpredictability, and formal security definitions and games are given to demonstrate that a PUF construction is secure. This facilitates the use of PUFs in cryptographic protocols, where the security of protocols must be reducible to existing hard problems.
[0018] Brzuska et al. construct cryptographic protocols for oblivious transfer, bit commitment and key exchange using PUFs in a univerally composable framework. The universally composable (UC) framework of Canetti (“Universally Composable Security: A new paradigm for cryptographic protocols,” Proceedings of the 42 nd IEEE Symposium on Foundations of Computer Science , FOCS'01, Washington, D.C., 2001, IEEE Computer Society) facilitates security proofs of protocols to be derived from sub-protocols in an arbitrary system.
[0019] The work of van Dijk et al. improves upon the work of Brzuska et al. by considering more realistic attack scenarios for cryptographic protocols involving PUF devices. Specifically, the authors' new security model focuses on when an adversary has access to the PUF device during a protocol. The authors demonstrate that any protocol for oblivious transfer or key exchange based solely on the use of a PUF is impossible when the adversary has posterior access to the PUF. Similar impossibility results are given for other security models, even when the PUF is modeled as an ideal random permutation oracle. The authors introduce formal security definitions in three models, and give novel protocols for bit commitment, key exchange and oblivious transfer under a subset of these models. Finally, the authors demonstrate that the application of Brzuska et al. to the universally composable framework of Canetti is not valid in these security models, and should be considered an open problem.
SUMMARY OF THE INVENTION
[0020] A device authentication system according to the present invention is for use with an authenticatable device having a physically-unclonable function (“PUF”) and constructed so as to, in response to the input of a specific challenge C, internally generate an output O that is characteristic to the PUF and the specific challenge C, the authenticatable device configured to: i) upon receiving the specific challenge C, generate a corresponding commitment value that depends upon a private value r, and ii) upon receiving an authentication query that includes the specific challenge C and a nonce, return a zero knowledge proof authentication value that corresponds to the commitment value. The device authentication system comprises an enrollment server having a working verification set that includes the specific challenge C and the authenticatable device's corresponding commitment value, wherein: a) the enrollment server is configured to generate an authentication token that corresponds to the zero knowledge proof authentication value and includes a blinded value depending upon the private value r and a random value that can be decrypted by the authenticatable device; and/or b) the system is configured to pre-process and convey data to the authenticatable device as part of an extended Boyko-Peinado-Venkatesan generation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is an illustration of the core components of the enrollment and authentication algorithms;
[0022] FIG. 2 is an illustration of the derived key tree construction;
[0023] FIG. 3 is an illustration of our experimental setup;
[0024] FIG. 4 is an illustration of overlapping intra- and inter-PUF error rate distributions;
[0025] FIG. 5 is an illustration of separated intra- and inter-PUF error rate distributions; and
[0026] FIG. 6 is an illustration of the experimentally observed intra- and inter-PUF error rate distributions.
DETAILED DESCRIPTION OF EMBODIMENTS
[0027] We review the enrollment and authentication protocols of Frikken et al. The authors consider PUF authentication in the context of banking authentication. The identity of banking clients is proved through a zero knowledge proof of knowledge, which demonstrates that the client knows a password and is in possession of a device capable of generating the discrete logarithm of a pre-enrolled group element. The construction is robust against many forms of attack, including device and server compromise by an adversary. Further, the construction is easily extended to support, panic passwords, where authentication succeeds but the banking server is notified that the client was under duress. We build on a subset of the authors' construction in this work, removing the user and focusing only on authenticating the hardware.
[0028] We modify their protocol in two ways. First, we reduce the number of necessary modular multiplications, as the PUF itself resides on a resource-constrained device (i.e., a device having a mathematic computational capability that is comparatively significantly less than that of personal computers widely available at the time of comparison). Second, we modify the enrollment algorithm such that it needs to occur only once. Many PUF-based authentication protocols assume a trusted enrollment stage, where the PUF device interacts with a server without adversarial intervention. As re-enrollment is costly, particularly in large-scale deployed systems, we modify the enrollment protocol to account for future failures or the need to generate additional enrollment tokens.
Overview
[0029] Referring to FIG. 1 , we first describe the core operations of the present protocols in the context of the primitives used in the construction of the enrollment and authentication protocols of Frikken et al. in terms of the primitives used in the construction.
The enrollment server issues a random challenge C to the device, which is passed as input to the PUF. Let O denote the response of the PUF to challenge C. The device chooses a random group element, randε p , and uses the extended BPV generator process (Boyko et al., “Speeding up discrete log and factoring based schemes via precomptations,” Advances in Cryptology EUROCRYPT' 98, vol. 1403 of Lecture Notes in Computer Science , pages 221-235, Springer Berlin Heidelberg, 1998) to construct a pair (r, g r mod p) that depends critically on the random group element rand, and substantially reduces the number of modular multiplications necessary to construct g r mod p. As the PUF output O is noisy, there is no guarantee that when queried on challenge C in the future, the new output O′ will satisfy O′=O. However, it is assumed that O and O′ will be t-close with respect to some distance metric (e.g. Hamming distance). Thus, an error correcting code may be applied to the PUF output such that at most t errors will still recover O. We apply error correction over the random group element rand, and blind this value with the output of the PUF O, so that the final helper value P=ECC(rand)⊕O reveals no information about rand. During recovery, computing the exclusive-or of ECC(rand)⊕O⊕O′ will return rand whenever O and O′ are t-close. This process is referred to as fuzzy extraction, and is described in detail in Section 33 . The pair (P, g r mod p) is returned to the enrollment server as a commitment to be used for authenticating the device in the future. Note that neither P nor g r mod p need to be kept secret, as without the PUF output O, the private exponent r cannot be recovered. When a server wishes to verify the device as authentic, it sends the tuple (C, P, Nonce) to the device, acting as the verifier in the zero knowledge proof protocol of Chaum et al. (“An improved protocol for demonstrating possession of discrete logarithms and some generalizations,” Proceedings of the 6 th annual international conference on Theory and Application of Cryptographic Techniques , EUROCRYPT'87, pages 127-141, Berlin, Heidelberg, 1988, Springer-Verlag). On input the challenge C, the device returns an output O′. The exclusive-or of the PUF output O′ and the error corrected helper data P is run through error decoding. So long as O′ and the original PUF output O are t-close, the decoding process will successfully recover the random group element rand. The group element rand is used as input to the extended BPV generator process, which returns a pair (r, g r mod p). After recovering the private exponent r, the device constructs the zero knowledge proof response pair (c′, w), acting as the prover. The server acts as the verifier in the zero knowledge proof, and accepts the device as authentic if the pair (c′, w) satisfies the proof condition.
We now give a formal description of the modeling assumptions about the PUF, as well as each primitive involved in the enrollment and authentication algorithms.
Model
[0038] We consider three principal entity types:
A set of servers , where each server s i ε controls authentication of devices on its system. A set of devices d i ε each with an embedded PUF. An adversary that wishes to masquerade as a legitimate device d i ε to obtain resources stored on some subset of the servers ′ ⊂ .
[0042] We assume that all entities are bound to probabilistic polynomial-time (PPT). That is, all entities may perform computation requiring polynomially many operations with respect to a global security parameter λ. In our setting λ refers to the number of bits in the group modulus p. The restriction implies that computation requiring exponentially many operations with respect to λ is not efficient for the agents, and will succeed with only negligible probability.
PUF Device
[0043] The specific PUF device used in the construction is of critical importance. Rührmair I define three distinct classes of PUF devices:
1. Weak PUF: A weak PUF is typically used only to derive a secret key. The challenge space may be limited, and the response space is assumed to never be revealed. Typical constructions include the SRAM (Holcomb et al., “Initial SRAM state as a fingerprint and source of true random numbers for RFID tags,” In Proceedings of the Conference on RFID Security , 2007), Butterfly (Kumar et al., “Extended Abstract: The Butterfly PUF protecting IP on every FPGA,” Hardware - Oriented Security and Trust , HOST 2008 , IEEE International Workshop , pages 67-70, 2008) and Coating (Tuyls et al., “Read-proof hardware from protective coatings,” Proceedings of the 8 th International Conference on Cryptographic Hardware and Embedded Systems , CHES'06, pages 369-383, Berlin, Heidelberg, 2006, Springer-Verlag) PUFs. 2. Strong PUF: A strong PUF is assumed to (i) be physically impossible to clone, (ii) impossible to collect a complete set of challenge response pairs in a reasonable time (i.e. on the order of weeks), and (iii) difficult to predict the response to a random challenge. 3. Controlled PUF: A controlled PUF satisfies all of the criteria for strong PUFs, and additionally implements an auxiliary control unit for computing more advanced functionalities.
[0047] In our setting, the controlled PUF is the most desirable. Further, we will require that it is physically impossible or at least difficult for an adversary to observe the output of the PUF that is passed to the auxiliary control unit or other intermediate calculations.
Formal PUF Definition
[0048] Formally, an ideal PUF construction satisfies Definition 1:
[0000] Definition 1. A physically unclonable function P d : {0, 1} κ 1 →{0, 1} κ 2 bound to a device d is a function with the following properties:
1. Unclonable: We require that Pr[dist(y, x)≦t|x←U κ 1 , y←P(x), z←P′]≦ε 1 , the probability of duplicating PUF P with a clone PUF P′, such that their output distributions are t-statistically close is less than some sufficiently small ε 1 . 2. Unpredictable: We require that (κ 2 ):=Pr[r=r′], denoting the probability of the adversary guessing the correct response r of the PUF P to the challenge c, is negligible in κ 2 for all probabilistic polynomial time adversaries . 3. Robust: We require that Pr[dist(y, z)>t|x←U κ 1 , y←P(x), z←P(x)]≦e ε 2 , the probability of a fixed PUF P yielding responses t-distant on the same input x is less than some sufficiently small ε 2 . This property is satisfied by binding the PUF device d with a (min, l, t, ε 3 ) fuzzy extructor (Gen, Rep). 4. Fuzzy Extraction: We require that during the enrollment phase for a PUF d, given a challenge c, the PUF computes (R, P)←Gen(r), where r←P d (c) and outputs P. The helper string P allows for R to be recovered when the challenge W′ is t-close to the original challenge W. 5. Indistinguishability: We require that the output of the PUF be computationally indistinguishable from a random string of the same length, such that the advantage of a PPT adversary is
[0000]
Adv
A
PUF
-
IND
(
)
≤
1
2
+
ε
3
,
[0000] where ε 3 is negligible.
Fuzzy Extraction
[0054] The output of a PUF device is noisy, and thus varies slightly despite evaluating the same input. In order to generate a fixed value for a given input over this noisy function, a fuzzy extructor is necessary. In our construction, we implement fuzzy extraction in the auxiliary control unit, such that the output is constant for a fixed input. We now formally define the Hamming distance construction of Dodis et al. (“Fuzzy extractors: How to generate strong keys from biometrics and other noisy data,” SIAM J. Comput ., pages 97-139, March 2008), based on the fuzzy commitment function by Juels et al. (“A fuzzy commitment scheme,” Proceedings of the 6 th ACM conference on Computer and Communications Security , CCS'99, pages 28-36, New York, 1999, ACM), which is used during the enrollment process.
[0000] Definition 2. Let C be a binary (n, k, 2t+1) error correcting code, and let rand←{0, 1} k be a random k-bit value. Then the following defines a secure sketch for input string O:
[0000] SS ( O ;rand)= O ⊕ECC(rand) (1)
[0055] In FIG. 1 , Enrollment Challenge [ 1 ] illustrates the enrollment server issuing a random challenge C to the device. The challenge is drawn uniformly at random from {0, 1} k for a k-bit challenge.
[0056] Definition 2 is used to build the Gen procedure for the enrollment phase, which must output a set rand, P , where rand is a random value and P is a helper string that is used to recover rand.
[0000]
Algorithm 1 The Gen Algorithm
Input : A prime order subgroup q of p * where p = 2q + 1; A challenge
c
O ← PUF(c)
rand ← random ε p *, a random group element
P ← O ⊕ ECC(rand)
return rand, P
[0057] PUF Query [ 2 ] illustrates the hardware device querying the PUF on challenge C, and yielding a response O.
Reducing Modular Multiplications
[0058] Modular exponentiation is an expensive operation, hindering the implementation of a PUF-based authentication system on resource-constrained devices, for example a mobile device (i.e., a device capable of being conveniently carried in one hand). We have identified a way to exploit a characteristic of the Frikken et al. protocol to adapt a means of reducing the onboard expense of this operation by an order of magnitude.
[0059] A protocol used in other contexts for securely outsourcing modular exponentiations to a server was given by Boyko et al., and their approach is typically referred to as utilizing BPV generators. Nguyen et al. (“Distribution of modular sums and the security of the server aided exponentiation,” Cryptography and Computational Number Theory , vol. 20 of Progress in Computer Science and Applied Logic , pages 331-342, 2001) then gave bounds on the distribution of modular sums, and demonstrated how BPV generators can be extended to reduce the computational load on resource-constrained devices to securely perform modular exponentiation with the aid of a server. Chen et al. (“New algorithms for secure outsourcing of modular exponentiations,” Computer Security , ESORICS 2012, vol. 7459 of Lecture Notes in Computer Science , pages 541-556, Springer Berlin Heidelberg, 2012) give methods to perform simultaneous modular exponentiation, and give a more thorough security analysis of their protocols.
[0060] Constructing our PUF-based authentication system with enrollment and authentication protocols that do not impose a specific structure on exponents enabled us to successfully adapt extended BPV generators to reduce the computational cost of computing modular exponentiation, as follows:
[0061] Parameter Selection: As suggested by the original authors of BPV generators, for a 256-bit prime p the parameters {n=256, k=16} are suggested to maintain the security of the discrete logarithm problem through the corresponding subset sum problem of breaking the BPV generator.
[0062] Preprocessing: Generate n random integers α 1 , . . . , α n ε p-1 to serve as exponents under the group * p . For each jε[ 1 , . . . , n], compute β j ≡g α i mod p, where g is the generator for the group * p . These values are stored in the set ={(α 1 , β 1 ), . . . , (α n , β n )}. This stage is performed by the server, and the database may be publicly revealed. In our setting, is stored on the device.
[0063] Pair Generation: When a secret pair (x, g x mod p) is to be generated, a random subset Sε[1, . . . , n] is generated such that |S|=k, 1≦k<n. We then compute:
[0000]
x
≡
∑
j
∈
S
α
j
mod
(
p
-
1
)
(
2
)
X
≡
∏
j
∈
S
β
j
mo
d
p
(
3
)
[0064] If x≡0 mod (p−1), the set. S is randomly regenerated until this equivalence does not hold. The secret pair is then (x, X). Thus, we have constructed the PairGen function, given by Algorithm 2, where ƒ′(•) is defined in Equation 4.
[0000]
Algorithm 2 The Pair Generation Algorithm
= {(α 1 , β 1 ), . . . , (α n , β n )}
p , a group of prime order
n, the number of bits in the modulus
k, the size of the subset
p, the prime group modulus
S ← random ⊂ [1, . . . , n] = ƒ′(R) to be kept secret
x ← α S 1
X ← β S 1
for 1 < j ≦ k do
x ← x + α S j mod (p − 1)
X ← X · β S j mod p
end for
return (x, X)
[0065] As PairGen(•) outputs a pair (x, X) we denote by PairGen x (•) the output x, and similarly denote by PairGen X (•) the output X=(g x mod p). Note that X need not be private, while the private exponent x must not be revealed.
[0066] The use of BPV generators results in a substantial reduction in the number of modular multiplications required to compute a secret pair (x, g x mod p). For a 256-bit prime p, the square-and-multiply algorithm requires 1.5n modular multiplications for an n-bit exponent to perform modular exponentiation. Thus, rather than requiring 384 modular multiplications, use of a BPV generator requires only 15, an improvement of an order of magnitude.
[0067] In our construction, the device is required to generate a specific pair (x, g x mod p) that is dependent on the output of the PUF(•) function. In the enrollment protocol (Algorithm 3), the generation function (Algorithm 1) takes as input a challenge c and returns a pair rand, P that depends on the output of PUF(c). The value rand is a randomly selected group element of p , which may be recovered by the PUF when given the same challenge c and the helper string P. Thus, we need the output of PairGen(n, k) to depend critically on the private value rand so that the same pair (x, X) is generated for a fixed challenge. We accomplish this by defining a deterministic function ƒ′(R) S for generating the set of indices S from the recovered value rand. Specifically, we define ƒ′(•) as follows:
[0000]
f
′
(
R
)
:
{
S
1
:
H
1
(
R
)
mod
n
…
…
S
k
:
H
n
(
…
H
1
(
R
)
)
mod
n
}
↦
S
(
4
)
[0068] Thus, the set of k indices S is generated through a hash chain over R, reduced modulo the total number of pairs, n. In our implementation, H(•) is the SHA-256 hash algorithm. As the group element rand is secret, knowledge of the definition of ƒ′(•) and the complete set ={(α 1 , . . . β 1 ), . . . , (α n , β n )} does not yield an advantage to any probabilistic polynomial-time adversary . We redefine function PairGen(•, •) to accept the index argument R and a set ={(α 1 , β 1 ), . . . , (α n , β n )}.
[0069] Referring still to FIG. 1 , BPV Generation [3] illustrates the device choosing a random group element randε p , and using the extended BPV generator process to construct a pair (r, g r mod p) that depends critically on the random group element rand, which substantially reduces the number of modular multiplications necessary to construct g r mod p.
[0070] Error Correction [4] illustrates the hardware device employing error correction. As the PUF output O is noisy, there is no guarantee that when queried on challenge C in the future, the new output O′ will satisfy O′=O. However, it is assumed that O and O′ will be t-close with respect to some distance metric (e.g. Hamming distance). Thus, an error correcting code may be applied to the PUF output such that at most t errors will still recover O. We apply error correction over the random group element rand, and blind this value with the output of the PUF O, so that the final helper value P=ECC(rand)⊕O reveals no information about rand. During recovery, computing the exclusive-or of ECC(rand)⊕O⊕O′ will return rand whenever O and O′ are t-close. This process is referred to as fuzzy extraction.
[0071] Enrollment Data Tuple [5] illustrates the hardware device constructing the pair (P, g r mod p), consisting of helper data P to be used for error decoding, and a commitment g r mod p to the exponent r. Note that neither P nor g r mod p need to be kept secret, as without the PUF output O, the private exponent, r cannot be recovered.
[0072] Store Enrollment [6] illustrates the server storing the hardware device enrollment token (P, g r mod p) for use in future authentication protocols.
[0073] The enrollment phase collects a series of n tokens {(c 1 , P 1 , g r 1 mod p), . . . , (c n , P n , g r n mod p)} from the PUF device in response to challenge queries by the server. The authentication tokens serve as commitments so that the device can be authenticated in the future. Note that no sensitive information is transmitted over the communication channel or stored in non-volatile memory. The private exponent r is generated by the device, and discarded after construction of g r mod p. When the exponent r is needed to authenticate the device through a zero knowledge proof protocol, an enrollment token (c i , P i , g r i mod p) allows the device to regenerate r and complete the proof. This provides a substantial benefit over alternative PUF authentication protocols, such as the naïve challenge-response protocol or a PKI construction, as both require private information to be stored in non-volatile memory.
[0074] Algorithm 3 describes the enrollment protocol in pseudocode.
[0075] Ideally, the enrollment process should be required only once, while the device is in a trusted environment at the manufacturer. Further, this process must ensure that in the event of a security breach, the device can remain active without re-enrollment through a minor change on the server side. We realize this property by constructing a challenge-response tree, where only the root node is directly derived from a PUF response. This minimizes the impact of an adversary succeeding in solving the discrete logarithm problem (e.g., when the modulus is small, as in our current implementation).
[0076] To prevent such an attack from forcing a re-enrollment process,
[0000] Algorithm 3 The Enrollment Algorithm for Server s do p ← 2q + 1 where p, q ∈ prime g ← random ∈ , a random group element
while g p - 1 2 ≢ - 1 mod p do
g ← random ∈ , a random group element end while end for for 1 ≦ i ≦ n do for Server s do c i ← random ∈ , a random group element Device d ← {c i , p, g} end for for PUF Device d do x = H(c i , p, g) R i , P i ← Gen(f(x)) where f(·) is the PUF function and Gen is Algorithm 1 helper i = P i token i = g r i mod q = PairGen X (f′(R i ), ) Server s ← {token i , helper i } end for for Server s do Store new enrollment entry {c i , (g r i mod p), P i } end for end for
we generate derived tokens from those collected during enrollment. Should an adversary succeed in solving the discrete logarithm problem, the recovered exponent will not help an adversary masquerade as the device to a server with a different derived token. The tiered authentication structure is as follows:
Definition 3. The complete verification set (CVS) is defined to be the set {(c 1 , P 1 , g r 1 mod p), . . . , (c n , P n , g r n mod p)}, where r i is linked to the PUF output through the Rep protocol (Algorithm 4).
[0077] The CVS consists of a set of challenges and their associated PUF responses, where the secret r i , known only given access to the PUF, is hidden in the exponent. From this set of root challenge-response pairs, we derive a tree structure for tiered authentication.
[0000] Definition 4. The working verification set (WVS) is a subset of the CVS, distinguished by the choice of a single root challenge-response pair (c i , P i , g r i mod p), where this pair serves as the root of the authentication tree.
[0078] In FIG. 2 , Working Verification Set [ 13 ] illustrates the selection of a member of the complete verification set to serve as the working verification set.
[0079] A given WVS chooses a single pair (c i , P i , g r i mod p) from the CVS. This pair will serve as the root of the authentication tree. We now describe how child nodes of this root value are derived.
[0080] Definition 5. A limited verification set (LVS) is a subset of the WVS, derived from the rot node by constructing the authentication set g r i e i mod p, c i , P i , E H(g ri mod p) (e i ) .
[0081] To create a child node, the root node chooses a random value e i ε p-1 and constructs g r i e i mod p. This value hides the root node g r i , as the child node cannot decrypt E H(g ri mod p) (e i ) to recover e i . The encryption function is defined as:
[0000] E k ( x )= x⊕k (5)
[0082] Derived Exponent [14] illustrates the generation of a random exponent e i , which is used to generate the derived token <g r i e i mod p, c i , P i , E H(g ri mod p) (e i )>. The random exponent e i blinds the root exponent r i .
[0083] We require that the child node is unable to generate the key, yet the PUF device must be able to decrypt the exponent e i to successfully prove knowledge of the exponent in the zero knowledge proof. We use H(g r i mod p) as the key, as the PUF can recover (ri, g r i mod p) using c i through the Gen protocol (Algorithm 1). The derivation structure for the verification sets is illustrated in FIG. 2 .
[0084] Derived Enrollment Token [15] illustrates the derived token to be distributed to other servers. The token g r i e i mod p, c i , P i , E H(g ri mod p) (e i ) allows another server to authenticate the device, while revealing nothing about the root exponent r i . Even if the derived token is compromised (revealing r i e i ), no information about r i is obtained, which prevents an adversary from masquerading as the hardware device to any server other than the one in possession of g r i e i mod p.
[0085] By only distributing derived tokens, an adversary able to solve the discrete logarithm problem recovers only r i e i mod (p−1). However, this does not allow to masquerade as the device with any other server, as each derived exponent e i is randomly generated. In order to impersonate the device with a different server, must solve another discrete logarithm problem. Further, recovering a derived exponent r i e i yields no advantage in attempting to recover r i , the root exponent. Rather than forcing a re-enrollment, the root server simply issues a new derived token to the compromised child server.
[0086] Returning to FIG. 1 , Authentication Challenge [7] illustrates a server attempting to authenticate a hardware device. The server sends the tuple (C, P, Nonce) to the device, acting as the verifier in the zero knowledge proof protocol of Chaum et al.
[0087] We now define the Rep procedure such that, on input O′ where dist(O, O′)≦t, the original PUF output rand may be recovered:
[0000] Definition 6. Let D be the decoding scheme for the binary (n, k, 2t+1) error-correcting code ECC, and let O′ be an input such that dist(O, O′)≦t. Then Rep is defined as:
[0000]
Rep
(
O
′
,
P
)
=
D
(
P
⊕
O
′
)
=
D
(
O
⊕
ECC
(
rand
)
⊕
O
′
)
=
rand
[0088] From Definition 6, we can now describe the Rep algorithm that allows a PUF output O′ that differs from the original output O by at most t to reproduce output rand such that Rep(O′)=rand using the public helper string P=O⊕ECC(rand):
[0000]
Algorithm 4 The Rep Algorithm
Input : A challenge c, Helper string P
O′ ← PUF(c)
rand ← D (P ⊕ O′)
return rand
[0089] We use the Gen and Rep algorithms in the Enrollment and Authentication protocols to ensure that the same random value rand is recovered so long as the PUF outputs O, O′ differ by at most t bits.
[0090] PUF Recovery [8] illustrates the hardware device querying the PUF on challenge C, and returning output O′, where O′ is not necessarily equal to O. If the device is authentic, verification will succeed when O′ differs from O by at most t-bits, where a t-bit error correcting code is used.
[0091] Error Correction Removal [9] illustrates the hardware device removing the error correction to recover the random group element. The exclusive-or of the PUF output O′ and the error corrected helper data P is run through error decoding. So long as O′ and the original PUF output O are t-close, the decoding process will successfully recover the random group element rand.
[0092] BPV Regeneration [10] illustrates the hardware device using the group element rand as input to the extended BPV generator process, which returns a pair (r, g r mod p).
[0093] Zero Knowledge Proof [11] illustrates the hardware device constructing a zero knowledge proof receipt. After recovering the private exponent r, the device constructs the zero knowledge proof response pair (c′, w), acting as the prover.
[0094] Verify Zero Knowledge Proof [12] illustrates the server attempting to verify the zero knowledge proof receipt (c′, w). The server acts as the verifier in the zero knowledge proof, and accepts the device as authentic if the pair (c′, w) satisfies the proof condition.
[0095] The authentication phase allows a server to verify that a client device is authorized to issue a request. Upon receiving a request from a device, the server engages in Chaum et al.'s zero knowledge proof protocol with the device d to establish permission to perform the request. The protocol is given as pseudocode in Algorithm 5.
[0000]
Algorithm 5 The Authentication Algorithm
for PUF Device d do
Server s ← request
end for
for Server s do
Device d ← {c, g, p, P, N} where N is a nonce and P is the helper
string
end for
for PUF Device d do
x ← H(c, g, p)
R ← Rep(f(x), P) where f (·) is the PUF output function and Rep
is Algorithm 4
v par ← random ∈ , a random group element
v ← PairGen x (f′(v par ), )
w ← v − c′(r = PairGen x (f′(R), )) mod p
t′ ← g v mod p = PairGen X (f′(v par ), )
c′ ← H(g, g r mod p = PairGen X (f′(R), ), t′, N)
Server s ← {c′, w}
end for
for Server s do
t′ ← g w g rc′ mod p
h = H(g, g r , g w g rc′ mod p, N)
Device d ← { accept : c ′ = h deny : c ′ ≠ h
end for
Implementation
[0096] As seen in FIG. 3 , we implemented our protocol on a Xilinx Spartan 6 FPGA SP605 development board as a proof of concept. One of ordinary skill will readily recognize how to adapt the hardware modular math engine to accept larger moduli, preferably at least 1024 bits. Both the PUF and modular math engine reside in the FPGA fabric, while all other operations were performed in software using the MicroBlaze processor. The device communicates with a desktop server over an RS232 connection. The enrollment and authentication protocols for the device and server were written in C, with a Java front end on the server side for the user interface and communicating with a local SQL database.
Error Correcting Code
[0097] Ideally, the inter-PUF error rate between two separate PUFs on the same challenge should be approximately 50%, while the intra-PUF error rate on a challenge should be substantially less. The greater the distance between these two distributions, the less likely false positives and false negatives are to occur. FIG. 4 illustrates the possible relationship between the inter-PUF and intra-PUF error in the case where the distributions overlap, making it impossible to avoid false positives and false negatives. FIG. 5 illustrates more distant distributions, where establishing a boundary to minimize false positives and false negatives is simpler. Finally, FIG. 6 illustrates the true inter-PUF and intra-PUF error rates we observed experimentally using three Xilinx development boards. The observed inter-PUF error rate has (μ=129, σ=5), which satisfies the ideal error rate of approximately half of the output bits differing. The observed intra-PUF error rate has (μ=15, σ=4).
[0098] Error decoding is the most computationally expensive operation that must be performed on the device. Our implementation chose a (n, k, 2t+1) BCH code (Bose et al., “On a class of error correcting binary group codes,” Information and Control , pages 68-79, 1960), where the code has length n, accepting original data of length at most k and correcting at most t errors. As we extract 256 bits from the PUF, originally a (1023, 668, 73) BCH code was used, so that up to 36 errors could be corrected. However, the PUF itself has only 32 bits, so to extract 256 bits the PUF is queried eight times. Rather than perform error correction over the 256 bit concatenated output, we use a (127, 71, 17) BCH code over each 32 bit output block. This change substantially reduces the size of the generating polynomial, which improved decoding speed despite having to run eight times, rather than once.
[0099] A benefit of this change is that a total of 64 bits may now be corrected in the PUF output while simultaneously reducing the decoding time. This comes at the price of only being able to correct 8 errors per 32-bit block, as the error correction code is now defined for block sizes of 32 bits, rather than 256 bits. Thus, the error correcting code handling up to 64 errors is likely to capture all of the intra-PUF error without introducing false positives by “correcting” inter-PUF error. On the other hand, while this gives the appearance of a 256-bit function, its security is equivalent to a brute force search over 2 32 elements. Thus, rather than attack a presumed 256-bit function, an adversary with some knowledge of the system could attack a 32-bit permutation and combine each smaller challenge-response pair block to generate the full PUF mapping. Consequently, it would be preferred to use a PUF accepting a 1024-bit input in a deployed system.
[0100] We experimentally determined the total time necessary for each operation, including storage and retrieval of values from a SQL database on the server, and communication between the device and the server. The server is equipped with an 8-core 3.1 GHz processor and 16 GB of RAM. Table 1 reports the average time per protocol over 1000 trials.
[0101] We note that all experiments had a 0% false positive and
[0000] TABLE 1 Performance Results Protocol Average Runtime St. Dev. Enrollment 1.2791 seconds 0.0603 Authentication 1.3794 seconds 0.0602 Derived Authentication 1.4480 seconds 0.0620
false negative rate. By setting the maximum error correction threshold at 64 bits, we are able to perfectly distinguish between PUF devices. However, in a deployed system, environmental factors may affect the intra-PUF error rate. If the intra-PUF error rate increases beyond the error correction threshold, the introduction of false negatives is inevitable.
[0102] A frequent concern about deploying PUFs in large scale authentication systems is that they may not be robust to varying environmental conditions. As the PUF hardware ages, the number of errors present in the responses is expected to increase. Maiti et al. (“The impact of aging on an FPGA-based physical unclonable function,” Field Programmable Logic and Applications ( FPL ), 2011 International Conference , pages 151-156) study the effects of simulated aging on PUF hardware by purposefully stressing the devices beyond normal operating conditions. By varying both temperature and voltage, the authors were able to show a drift in the intra-PUF variation that, over time, will lead to false negatives. We mitigate this inevitable drift by choosing the error correction threshold to maximize its distance from both the intra- and inter-PUF error distributions.
[0103] In authentication systems, false negatives tend to be less damaging than false positives. Maiti et al. note that the error drift strictly affected the intra-PUF error rate distribution. Thus, there is a tendency for intra-PUF error rates to drift towards the maximum entropy rate of 50%. This inevitability should be considered when determining the re-enrollment cycle or the device lifespan. | A device authentication system for use with an authenticatable device having a physically-unclonable function and constructed to, in response to input, of challenge C, internally generate an output O characteristic to the PUF and the challenge C, and configured to: i) upon receiving challenge C, generate a corresponding commitment value that depends upon a private value r, and ii) upon receiving an authentication query that includes the challenge C and a nonce, return a zero knowledge proof authentication value that corresponds to the commitment value. The system comprises an enrollment server having a working verification set that includes challenge C and corresponding commitment value, wherein: a) the enrollment server is configured to generate an authentication token that corresponds to the authentication value and includes a blinded value depending upon the private value r and a random value decryptable by the authenticatable device; and/or b) the system is configured to pre-process and convey data to the authenticatable device as part of an extended Boyko-Peinado-Venkatesan generation. | 7 |
[0001] This is a continuation of Ser. No. 09/852,993 filed May 10, 2001
FIELD OF THE INVENTION
[0002] This invention is directed to a composition that may be used to treat a substrate. More particularly, the invention is directed to a composition that improves the characteristics of a substrate, like a fabric. The characteristics of the substrate are improved as a direct result of the composition and substrate coming into contact, and the improvements may be realized without the need to employ a mechanical washer, dryer, or ironing device.
BACKGROUND OF THE INVENTION
[0003] It is desirable in busy households to minimize the amount of work required to treat substrates. Particularly, it is very desirable to minimize the amount of work required to reduce or even eliminate, for example, wrinkles in substrates such as clothing. This is especially true when a consumer has worn clothing for a brief period of time and plans to wear the clothing a second time before having it, washed, dried and/or ironed.
[0004] Attempts to reduce wrinkles in clothing have been made, and especially with the introduction of durable permanent press treatments in the textile industry. Such treatments are known to employ polycarboxylic acids to strengthen the fibers of the textile, thereby rendering them less likely to wrinkle. Notwithstanding the above-described permanent press treatments, it is well settled that the effects of such treatments do not last long after the textiles (e.g., clothing) are subjected to a few washing cycles.
[0005] A need exists to reduce wrinkles in substrates, like clothing, that may not be subjected to washing, drying and/or ironing, even if the substrates have been subjected to permanent press treatments. This invention, therefore, is directed to a composition that improves the characteristics of a substrate as a direct result of the substrate coming into contact with the composition. The characteristics which are improved by the composition described in this invention include the reduction of substrate wrinkles and/or the reduction of substrate shape distortion.
[0006] Additional Information
[0007] Efforts have been disclosed for spraying surfaces. In U.S. Pat. No. 5,783,544, a spray composition for reducing malodor is described.
[0008] Still other efforts have been disclosed for spraying surfaces. In U.S. Pat. No. 5,663,134, a spray composition with less than 1.0% by weight of monohydric alcohol is described, and the composition is used to reduce malodor impressions on inanimate surfaces.
[0009] Even further, additional attempts have been made to spray surfaces. In U.S. Pat. No. 5,534,165, spray compositions with odor absorbing features are described.
[0010] None of the references above disclose a composition that may be sprayed on to a substrate in order to reduce wrinkle formation and/or shape distortion of the substrate. As used herein, substrate is defined to mean a textile having the capacity to wrinkle, including curtains, table cloths, upholstery, and especially, clothing. Substrate enhancing agent is defined to mean a compound (including oligomers and polymers) that results in a reduction in wrinkle formation and/or shape distortion of a substrate. Such a substrate enhancing agent is also meant to include a compound that enhances the wrinkle reducing properties of conventional wrinkle reducing additives.
SUMMARY OF THE INVENTION
[0011] In a first embodiment, this invention is directed to a composition for improving substrate characteristics, the composition comprising:
[0012] (i) from about 0.1 to about 20.0% by weight of a least one substrate enhancing agent selected from the group consisting of a polyhydric alcohol, a polyether, a monohydric alcohol and a mixture thereof; and
[0013] (ii) greater than about 5.0% by weight water wherein the polyhydric alcohol is at least a C 4 polyhydric alcohol, the polyether comprises at least one alkylene chain of at least 4 carbons and the monohydric alcohol is at least a C 5 monohydric alcohol.
[0014] In a second embodiment, this invention is directed to a method for reducing wrinkles and/or shape distortion of a substrate by using the composition described in the first embodiment of this invention.
[0015] In a third embodiment, this invention is directed to an article of manufacture comprising the composition described in the first embodiment of this invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, may be best understood by reference to the following description taken in conjunction with the accompanying drawing FIGURE in which:
[0017] The FIGURE illustrates a side view of a trigger sprayer which may be used to dispense the composition for improving substrate characteristics of this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] There is no limitation with respect to the type of polyhydric alcohol used in this invention other than that the polyhydric alcohol has at least a C 4 carbon chain. Polyhydric alcohol, as used herein, is defined to mean a compound with more than one hydroxy group and no ether links within its backbone. An illustrative list of the polyhydric alcohols which may be used in this invention includes C 4 to C 18 alkane diols, like 1,4-butane diol, 1,5-pentane diol and 1,10-decane diol. Others include C 6 to C 18 cycloalkane diols like 1,4-cyclohexane diol.
[0019] The polyhydric alcohols which may be used in this invention can be prepared, for example, by base-or-acid-catalyzed cleavage reactions of epoxides, or by the oxidation of alkenes. Such polyhydric alcohols are also made commercially available by suppliers like Aldrich Chemical.
[0020] Regarding the polyethers which may be used in this invention, these compounds may be oligomers or polymers and have, in their respective backbones, at least one alkylene chain having at least 4 carbon atoms. An illustrative list of the polyethers (e.g., polyalkylene glycols) which may be used in this invention includes polybutylene glycol, polypentylene glycol, polyhexylene glycol, and any copolymers (including terpolymers) of the same.
[0021] The polyethers used in this invention are typically made by conventional techniques which include the polymerization of alkylene oxides via a mechanism initiated by anions. Such polyethers are also made commercially available by suppliers like Dow Chemical, and typically have a weight average molecular weight (mw) from about 500 to about 20,000; and preferably, from about 1000 to about 10,000, including all ranges subsumed therein.
[0022] The monohydric alcohols which may be used in this invention are limited only to the extent that they include alcohols having at least 5 carbon atoms in a linear chain. The preferred monohydric alcohols include those which have greater than about 7 carbon atoms. The most preferred monohydric alcohols include those which have greater than about 15 carbon atoms, like cetyl alcohol, octadecyl alcohol, and mixtures thereof (e.g., tallow alcohol).
[0023] The monohydric alcohols that may be used in the present invention may be prepared by any conventional technique, such as those which react acid chlorides with organometallic compounds. The monohydric alcohols which may be used in this invention may also be purchased from suppliers like Sigma.
[0024] There is no requirement for the substrate enhancing agent of this invention to be saturated, and therefore, such an agent may comprise sites of mono- or polyunsaturation. In an especially preferred embodiment, the substrate enhancing agent of this invention has a weight average molecular weight of greater than about 180 or a boiling point greater than about 216° C., or both.
[0025] There is no limitation with respect to how the composition of the present invention is made as long as the desired components are mixed to produce a composition that may be applied to a substrate. For example, the substrate enhancing agent may be added to a mixing vessel along with water. The amount of water in the composition that may be used to treat a substrate is greater than 5.0%, and typically, from about 70.0% to about 99.9% by weight of the total weight of the composition. Most preferably, however, water makes up from about 75.0% to about 97.0% by weight of total weight of the composition, including all ranges subsumed therein. The mixing of desired components may occur at conventional mixing rates. The temperature and pressure during mixing may vary, as long as the desired composition for improving substrate characteristics may be made. Typically, however, the composition of this invention may be made by mixing under conditions of moderate shear, with temperature being from about 25° C. to about 85° C. and pressure being atmospheric.
[0026] Optional additives which may be employed in the compositions of the present invention include low molecular weight alkanols (i.e., alcohols with a backbone of four (4) carbons or less). The low molecular weight alcohols which may be used in this invention may assist in improving the characteristics of the substrate being treated with the composition of this invention. Also, such low molecular weight alcohols can significantly decrease the drying time of the composition applied to the substrate, thereby enabling the consumer to, for example, use the substrate (e.g., clothing) shortly after being contacted with the composition. The amount of low molecular weight alcohols which may be used in this invention typically is from about 0.0% to about 10.0%, and preferably, from about 0.1 to about 9.0%, and most preferably from about 0.5% to about 5.0% by weight, based on total weight of the composition, including all ranges subsumed therein.
[0027] Other optional additives which may be used in conjunction with the substrate enhancing agents of the present composition include known lubricants like silicon comprising compounds, substituted vegetable oils, fatty acids or fatty acid esters and quaternary ammonium compounds and surfactants.
[0028] The silicon comprising compounds which may be used in this invention include those that may generally be classified as siloxanes, preferably those having a viscosity from about 10 to about one million centistokes at ambient temperature. The siloxanes which may be used in this invention include polydimethylsiloxane; ethoxylated organosilicones; polyalkyleneoxide modified polydimethylsiloxane; linear aminopolydimethylsiloxane polyalkyleneoxide copolymers; betaine siloxane copolymers; and alkylactam siloxane copolymers. Of the foregoing, the preferred siloxane is a linear aminopolydimethylsiloxane polyalkyleneoxide copolymer sold under the name Magnasoft SRS (available from Witco, Greenwich, Conn., USA). Silsoft A-843, another aminopolydimethylsiloxane polyalkyleneoxide copolymer available from Witco, is also a particularly preferred lubricant which may be used. The most preferred siloxane is, however, a polydimethylsiloxane sold under the name HV-600 by Dow Chemical.
[0029] Regarding the silicon comprising compounds, such compounds are preferably included in the compositions of the present invention in an amount from about 0.1 to about 10%, and preferably, from about 0.1% to about 5%, and most preferably, from about 0.3 to about 1.5% by weight silicon comprising compound (or mixtures of silicon comprising compounds), based on total weight of the composition for improving substrate characteristics, including all ranges subsumed therein.
[0030] The substituted vegetable oils which may be used in this invention include substituted canola, castor, palm, peanut and corn oil, including mixtures thereof. Regarding the substitution, any groups that increase the water solubility of the oil may be substituted thereon. Such groups include sulphate, sulphonate, phosphate and phosphonate groups as well as polyalkylene oxide groups like polyethylene oxide. As to the degree of substitution, the vegetable oil is substituted to the point where it is almost soluble in water, yet able to lubricate the fabrics it comes in contact with. Typically, from about 0.1 to about 15.0%, and preferably, from about 0.2 to about 10.0%, and most preferably, from about 0.3 to about 5.0% by weight substituted vegetable oil is used. Preferred substituted vegetable oils are sulfated caster oil such as SCO-50 and SCO-75, both made commercially available by B.F. Goodrich.
[0031] The fatty acid or fatty acid ester which may be used in this invention includes fatty acids or there esters of stearic, oleic, palmitic, lauric, isostearic, myristic or behenic acids, as well as mixtures thereof. It is also understood that the fatty acid or esters thereof which may be used in this invention can comprise a mixture of compositions such as carnauba wax, candelilla wax, and natural or synthetic bees wax. The amount of fatty acid or esters thereof which may be used in the composition of this invention is typically from about 0.1 to about 10.0%, and preferably, from about 0.2 to about 5.0%, and most preferably, from about 0.3 to about 3.0% by weight fatty acid ester, based on total weight of the composition for improving substrate characteristics, including all ranges subsumed therein.
[0032] The quaternary ammonium compounds which may be used in this invention include any of those typically found in fabric conditioning products. Such quaternary ammonium compounds include dialkyldimethylammonium chlorides and trialkylmethyl ammonium chlorides, wherein the alkyl groups have from about 12 to about 22 carbon atoms. Other quaternary ammonium compounds which may be used are, for example, ester containing quaternary ammonium compounds N,N-di(tallowyl-oxy-ethyl)-N,N-dimethyl ammonium chloride, N,N-di(tallowyl-oxy-ethyl)-N-methyl, N-(2-hydroxyethyl) ammonium chloride and mixtures thereof.
[0033] The amount of quaternary ammonium compound employed in the composition of this invention is typically from about 0.1 to about 5.0%, and preferably, from about 0.2 to about 4.0%, and most preferably, from about 0.3 to about 3.0% by weight quaternary ammonium compound, based on total weight of the composition for improving substrate characteristics, including all ranges subsumed therein.
[0034] The only limitation with respect to the surfactant which may be used in this invention is that the surfactant is compatible with the substrate enhancing agent used in the substrate treating compositions of this invention. The surfactants that may be used in this invention include commercially known nonionic, anionic, cationic, amphoteric and zwitterionic surfactants, including mixtures thereof. Such surfactants typically make up from about 0.5 to about 10 wt. % of the total weight of the substrate treating composition.
[0035] Nonionic surfactants are the preferred surfactants and they are defined to include those surfactants generally classified as fatty acid or alcohol condensates. Such surfactants are typically sold under the names Neodol, Plurafac, Dehypon and Synperonic and made commercially available from suppliers like Shell Chemical Company, Union Carbide, Condea, Stepan and BASF. The preferred nonionic surfactant used in this invention is an ethoxylated nonionic sold under the name Neodol 25-9 and made available by Shell Chemical Company.
[0036] It is also noted herein that odor reducing additives, like cyclodextrin, may be used in the composition of this invention. Cyclodextrin, as used herein is meant to include cyclodextrins containing from 6 to 12 glucose units; especially, alpha-cyclodextrin, beta-cyclodextrin, gamma-cycodextrin, derivatives thereof or mixtures thereof. The amount of cyclodextrin which may be used is typically from about 0.1 to about 7.0% by weight cyclodextrin, based on total weight of the composition for improving substrate characteristics, including all ranges subsumed therein. A more detailed description of such odor reducing additives may be found in International Application No. WO 98/56890.
[0037] Still other optional additives which may be used in this invention include well known and commercially available colorants, fragrances such as Koala Kool MOD-C made available by Takasago, preservatives, pH control agents, viscosity adjusting agents such as inorganic salts, hydrotropes such as sodium xylene sulfonate, anti-oxidants such as butylated hydroxy toluene, foam control agents, chelants, enzymes (e.g., lipases, amylases, proteases), dye transfer inhibitors and anti-clogging agents. When used, these optional additives, collectively, make up less than about 10.0% by weight of the total weight of the composition for treating a substrate.
[0038] The composition for treating a substrate of this invention may be applied to the substrate with, for example, a dispenser like roller, aerosol dispenser, pump sprayer or trigger sprayer. The FIGURE depicts a trigger sprayer 10 having a head 12 , a neck 14 and a bottle 16 . The bottle 16 is connected to the neck 14 via twist connector 18 . Trigger 20 , when engaged, causes the composition for improving substrate characteristics 22 to be drawn through the delivery tube 24 and the exit nozzle 26 in order to deliver the composition for improving substrate characteristics 22 on to a substrate (not shown).
[0039] The composition for improving substrate characteristics of this invention is preferably applied on to a substrate at portions of the substrate that are most likely to wrinkle. If desired, however, the entire substrate may be subjected to the composition. When applying the composition for improving substrate characteristics, the amount of composition applied is enough to improve the characteristics of the substrate and just enough to allow the substrate to dry (at ambient temperature) in under about three (3) hours, and preferably, in under about one (1) hour, and most preferably, in under about one-half (½) hour. Also, it is noted that after applying the composition of the present invention to the substrate, little or no discernible markings (e.g., stains, water marks or rings) may be found on the substrate when the composition is completely dry.
[0040] Instructions may be provided with the composition for improving substrate characteristics of this invention. Such instructions, where applicable, educate an end user to apply the composition of this invention to a substrate and then to immediately (e.g., within about five (5) minutes) hang the substrate up or place the substrate on a flat surface. The instructions may also suggest to the end user to apply the composition of this invention to a substrate and then to either tension and smooth the garment or to iron the substrate before or after (preferably after) the composition for improving substrate characteristics dries.
[0041] The examples are provided to further illustrate and facilitate a better understanding of the compositions for improving substrate characteristics of this invention. The examples are not meant to limit the accompanying claims.
Component 1 2 3 4 5 6 Ethanol 5.0 5.0 2.0 — 4.0 3.0 Sulfated castor oil 0.5 2.0 — — — — Silicone B — — .5 1.0 — 2.0 Ethoxylated nonionic C 1.0 2.0 1.0 — 2.0 1.0 Tallow alcohol 3.0 1.5 — — 5.0 4.0 Methyl methoxy — 2.0 5.0 4.0 4.0 3.0 butanol Ditallow, dimethyl — — — — 2.0 — ammonium chloride Octadecyl alcohol — — 2.0 4.0 — — Fragrance D 0.5 0.5 — 0.5 02 0.5 Water To To To To To To 100% 100% 100% 100% 100% 100% | The present invention is directed to a composition for improving substrate characteristics. The composition has a substrate enhancing agent, like a monohydric alcohol, and the composition reduces wrinkles in substrates that have not been subjected to ironing. | 3 |
TECHNICAL FIELD
The present invention relates generally to a method for forming a photographic element using a silver halide emulsion, more particularly by using a silver halide emulsion containing a mixture of grain sizes which enhance performance of such elements.
BACKGROUND OF THE INVENTION
Reversal photographic elements produce a photographic image for viewing by a process of exposure of the element (film) to an image, development of the film to produce a negative of the image to be viewed, and then uniform exposure and/or fogging of residual silver halide and processing to produce a second, viewable image. In the preparation of a photographic elements for color reversal imaging, a coupler used to form a colored image is incorporated into a silver halide emulsion layer. Two methods have been used to coat film supports with emulsions in which a coupler is incorporated. In one, the coupler is added to the silver halide emulsion, and a single melt is made by heating the mixture to a temperature in the range of 35°-46° C. The resulting emulsion is filtered and then coated on the film support.
A second method provides better filtration control through a dual melt procedure in which the emulsion and coupler melts are made separately. Each is formed as a gelatin melt and heated to a temperature sufficiently high to render the melt flowable, typically about 40° C. The separate melts are mixed together and then the resulting mixture is immediately coated on the support. The coupler composition is usually hydrophobic, such that the admixture is an oil-in-water emulsion.
Mixtures of different kinds or sizes of silver halide grains have been used in various applications, such as X-ray films. See Honda et al. U.S. Pat. No. 4,639,417, issued Jan. 27, 1987, and Kuwabara, U.S. Pat. No. 4,786,587, issued Nov. 22, 1988. A combination of a separately prepared tabular grain emulsion and a Lippmann emulsion have been used for the purpose of transferring a dye from the silver salt grains to the tabular grains. See European Patent Publication No. 267,483.
High aspect ratio tabular grain silver haloiodide emulsions have been used in color reversal imaging to provide a variety of photographic advantages, such as improvements in speed-granularity relationships, increased image sharpness, and reduced blue speed of minus blue recording emulsion layers. Ellis, U.S. Pat. No. 4,801,522, issued Jan. 31, 1989 describes a process for preparing such tabular grains. It has been further recognized that the photographic properties of the tabular emulsion can be further improved by using an emulsion layer containing a blend of tabular silver haloiodide grains and relatively fine grains made of a silver salt more soluble than silver iodide. See Sowinski et al., U.S. Pat. No. 4,656,122, issued Apr. 7, 1987. Sowinski et al. give examples of using fine grains of silver bromide (AgBr), silver chlorobromide (AgClBr) or silver chloride (AgCl) with tabular grains of silver chlorobromoiodide (AgClBrI). However, this patent does not recognize that the manner in which the fine grains are added to the tabular grains in forming the photographic element can influence the performance of the resulting film.
SUMMARY OF THE INVENTION
A method for forming a photographic element according to the invention includes the steps of heating an emulsion containing grains of a radiation sensitive silver haloiodide to form a first melt, separately heating an emulsion containing grains of a silver salt effective to enhance the photographic properties of the silver haloiodide emulsion, and substantially insensitive to radiation at wavelengths at which the silver haloiodide grains are sensitive, to form a second melt, and coating the first and second melts onto a photographic support to form an image recording layer. The coating step is preferably carried out by blending the first and second melts together, then immediately coating the silver haloiodide emulsion onto the support. In a preferred embodiment, the silver salt is essentially silver chloride in the form of relatively fine cubic grains, and the silver haloiodide is in the form of tabular grains larger than the cubic grains. The foregoing procedure unexpectedly improves the speed of the resulting photographic element. For color reversal photographic elements, the melt containing the fine silver salt grains is conveniently the coupler melt.
DETAILED DESCRIPTION
In one aspect this invention is directed to a photographic element capable of forming a reversal image comprising a support and, coated on the support, at least one image recording emulsion layer comprised of a dispersing medium and a blend of radiation sensitive silver haloiodide grains and a second grain population present in a concentration sufficient to improve reversal photographic imaging, the second grain population having been added directly to the support without premixing with the emulsion containing the radiation sensitive silver haloiodide grains. The second grain population is generally incapable of forming a latent image, but extends the exposure latitude imparted to the radiation sensitive grains.
As the radiation sensitive grains, silver haloiodide tabular grains are preferred for the reasons noted above. Silver haloiodides comprise grains containing silver ions in combination with iodide ions and at least one of chloride and bromide ions. The tabular haloiodide grains employed in the practice of this invention contain in addition to iodide at least one of bromide and chloride. Such silver haloiodides include silver bromoiodides, silver chlorobromoiodides, and silver chloroiodides. Silver bromoiodide emulsions generally exhibit higher photographic speeds, and are thus preferred. Iodide must be present in the tabular silver haloiodide grains in a concentration sufficient to influence photographic performance, typically at least about 0.5 mole percent iodide. The silver haloiodide grains generally contain less than 15 mole percent iodide. Preferred iodide levels for tabular silver haloiodide grains are from 1 to 8 mole percent, optimally 2 to 7 mole percent. All of these iodide mole percentages are based on total silver present in the tabular grains.
Tabular grains are herein defined as grains having two substantially parallel crystal faces that are larger than any other crystal face on the grain. Tabular grain emulsions preferably have at least 50% of the grain population accounted for by tabular grains that satisfy the formula AR/t>25. In this formula, AR stands for aspect ratio, which equals D/t. D is the diameter of the grain in micrometers and t is the thickness of the grain between the two substantially parallel crystal faces in micrometers. The grain diameter D is determined by taking the surface area of one of the substantially parallel crystal faces, and calculating the diameter of a circle having an area equivalent to that of the crystal face. The grain size of the silver halide may have any distribution known to be useful in photographic compositions, and may be either polydisperse or monodisperse.
The fine silver salt grains preferably have an average diameter less than 0.7 μm, and are generally smaller than the photosensitive grains. However, under some circumstances the photosensitive grains may be the same size or slightly smaller than the silver salt grains. Thus, although the silver salt grains are referred to hereafter as the fine grains, the invention is not so limited.
The fine grains are preferably cubic grains, which are well known and easy to form, but other grain types such as octahedral, tetrahedral and tabular grains could be employed. The fine grains consist essentially of a silver salt more soluble in the emulsion medium than silver iodide. The relatively fine grain emulsion can, for example, be a relatively fine grain silver chloride, silver bromide, or silver thiocyanate emulsion, the preparations of which are well known to those skilled in the art and form no part of this invention. Emulsions combining the foregoing, such as silver chlorobromides, can also be used. However, the advantages of the invention are maximized using silver chloride, as shown in the example below.
The grains consisting essentially of the silver salt are fine and more soluble in the emulsion medium as compared to the photosensitive silver haloiodide grains. In general, the permissible size of this fine grain population blended with the radiation sensitive grains is a direct function of the solubility of the silver salt forming these grains. More soluble fine grains such as cubic AgCl may be larger than less soluble fine grains such as AgBr to achieve similar speed enhancement. The fine grain population preferably exhibits an average grain diameter of less than 0.7 μm, optimally 0.14 to 0.64 μm for silver chloride cubes. Any concentration of the second (fine) grain population can be employed that is capable of enhancing the photographic properties (e.g., speed and contrast) of the reversal photographic elements. Minimum fine grain population concentrations can range from as low as about 0.3 mole percent, based on total silver in the coated (blended) grain emulsion layer, with concentrations above about 1 mole percent being preferred and concentrations above about 8 mole percent being most preferred for maximizing photographic benefits.
The fine grain population is incapable of forming a latent image, and acts to extend the exposure latitude imparted to the emulsion layer by the larger silver haloiodide grains. When the large grains have received sufficient light exposure to reach their maximum level of developability, the fine grain population has not yet reached a threshold exposure for producing a latent image. The fine grain population need not be capable of forming a latent image at any level of exposure, since the latent image forming capability of the second grain population is not utilized in enhancing reversal imaging characteristics. A fine grain population having a latent image forming capability is not excluded from the practice of the invention, but its threshold exposure level is normally beyond the intended exposure latitude of the photographic element. Thus, the fine grain population preferably requires at least 0.3 log E greater exposure than that required to bring the large grains to a maximum level of developability. The relative insensitivity of the fine grains to exposing radiation as compared to the large grains can result from the difference in mean diameters. The difference in radiation sensitivity of the two grain populations can be increased by chemically sensitizing and/or spectrally sensitizing only the large grains. Conventional techniques for desensitizing the fine grain population can, if desired, be employed.
Reversal photographic elements of the invention can take the form of either black-and-white or color reversal photographic elements. Such photographic elements include a conventional photographic support, such as a transparent film support, onto which a grain emulsion layer is formed as described above. Although conventional overcoat and subbing layers are preferred, only the blended grain emulsion layer is essential. Following imagewise exposure, silver halide is imagewise developed to produce a first silver image, which need not be viewable. The first silver image can be removed by bleaching before further development when a silver or silver enhanced dye reversal image is desired. Thereafter, the residual silver halide is uniformly rendered developable by exposure or by fogging. Development produces a reversal image. The reversal image can be either a silver image, a silver enhanced dye image, or a dye image only, depending upon the specific choice of conventional processing techniques employed. If a dye only image is being produced, silver bleaching is usually deferred until after the final dye image is formed.
Photographic elements of this invention are preferably color reversal photographic elements capable of producing colored, particularly multicolored, images. Illustrative of such color reversal photographic elements are those disclosed by Kofron et al., U.S. Pat. No. 4,439,520 and Groet, U.S. Pat. No. 4,082,553, each cited above and here incorporated by reference. In a simple form such a color reversal photographic element can comprise a support having coated thereon at least three color forming layer units, including a blue recording yellow dye image forming layer unit, a green recording magenta dye image forming layer unit, and a red recording cyan dye image forming layer unit. Each color forming layer unit is comprised of at least one radiation sensitive silver halide emulsion layer. At least one radiation sensitive emulsion layer in each color forming layer unit is comprised of a blended grain emulsion as described above. The blended grain emulsions in each color forming layer unit can be chemically and spectrally sensitized as taught by Kofron et al., U.S. Pat. No. 4,439,520. In a preferred form chemical and spectral sensitization of the tabular grain emulsion is completed before blending with the fine grain population, which therefore remains substantially free of sensitizing materials.
One or more dye image providing materials, such as couplers, are preferably incorporated in each color forming layer unit, but can alternatively be introduced into the photographic element during processing. The melt containing the coupler comprises a conventional coupler mixture in a gel medium and further can contain the fine grains according to the invention. It has been found that the fine silver salt grains are less soluble in the coupler melt due to the absence of the silver haloiodide. For example, AgCl is more soluble than AgBrI under the conditions present in the emulsion containing AgBrI as the silver haloiodide. If the photosensitive AgBrI grains are present together with the AgCl grains during melting, bromine and iodine present in the photosensitive grains can attack the non-photosensitive AgCl grains. If the melts are prepared separately, more intact AgCl grains reach the photographic element as compared to a procedure wherein the fine grain population is preblended with the silver haloiodide emulsion prior to coating.
In a preferred dual melting procedure according to the invention, the silver haloiodide emulsion and the melt containing the silver salt grains, and the coupler, if needed, are made separately. The specific melt medium employed is not critical and may, for example, be gelatin. To hinder migration of the dye to the silver salt grains, the latter may also be treated with the dye, even though the silver salt grains are non-photosensitive compared to the silver haloiodide grains. If no dye is used on the silver haloiodide grains, none is used on the silver salt grains.
Each melt is then separately heated to a temperature sufficiently high to render the melt flowable, typically about 40° C. The separate melts are then mixed immediately prior to coating onto the support, which is carried out in a conventional manner using a knife or doctor blade. For this purpose, "immediately" means as soon as possible in practice, preferably less than about one minute. If this time is exceeded, the silver salt begins to degrade in the presence of the silver haloiodide. Under some conditions the melts can also be coated on the support successively, without preblending. Either procedure minimizes dissolution of the silver salt grains.
Other conventional layers may be formed, such as an undercoated antihalation layer (i.e., interposed between the silver haloiodide emulsion and the support) or an overcoated protective layer, for example, of gelatin, which is then hardened. In forming a high-speed color reversal film according to the invention using a silver bromoiodide T-grain emulsion containing at least 6 mole % iodine, the speed enhancement was maximized by using as the fine grains AgCl or AgClBr containing up to about 30 mole % Br.
The invention is illustrated by the following examples.
EXAMPLE 1
Four emulsions A, B, C and D were initially prepared. In the following description, the amounts used provided one mole of silver per emulsion.
The tabular grain emulsion, Emulsion A, was first prepared as follows. Silver nitrate (0.25 N) was added to a kettle containing 6.4 g/l NaBr, 0.2% bone gel, and 0.436 liter of distilled water at 70° C. at 6.387 cc/min for 11/2 minutes. This was followed by addition of 0.2244 l of 1.57% bone gel. Emulsion grains were then grown by adding to the kettle, in an increasing flow, 2N silver nitrate, together with 2.75 N NaBr which controlled pAg at 8.6. Flow rates of silver nitrate were 3.138 cc/min for 10 minutes, increasing to 5.826 cc/min for 10 minutes, increasing to 9.4113 cc/min for 10 minutes, and finally to 13.891 cc/min for 10 minutes. These total 40 minute runs at 70° C. resulted in 54% of total silver being precipitated. Kettle pAg was then brought to about 9.5 by adding NaBr solution for 4 min at 13.44 cc/min and then 0.06 mole of a preformed silver iodide emulsion (about 0.05 μm) was added. The pAg was then brought to 8.6 by addition of 2 N silver nitrate, and grains were grown for 9 minutes. Remaining silver was run at 8.79 cc/min to reduce pAg to 8.0 and was run at 3.884 cc/min with NaBr solution for 5 min while maintaining pAg 8.0.
The resulting emulsion was cooled to 40° C. and ultrafiltered by the procedure of Mignot, U.S. Pat. No. 4,334,012, issued Jun. 8, 1982, the contents of which are incorporated herein by reference. 220 cc distilled water containing 5.5 g bone gel at 40° C. was added to the filtered emulsion. The emulsion pH and pAg were adjusted to 6.2 and 8.2 at 40° C., respectively. The resulting emulsion contained tabular grains with an aspect ratio (AR) of about 20 and AR/t=187. Median grain size was about 2.1 μm, and mean thickness was estimated to be 0.107 μm.
Emulsion A was then sensitized. To one mole of the Emulsion A there was added 0.1 mg Hgl 2 , 100mg NaCNS, 733 mg of dye A, below, 244 mg of dye B, below, 5.5 mg of sodium thiosulfate pentahydrate, 1.65 mg KAuCl 4 , 22 mg of 3-methylbenzothiazolium iodide, and 2,750 mg KCl at 40° C. The temperature of the emulsion was elevated to 63° C. and held at that temperature for 15 minutes, whereafter it was cooled to chill set the emulsion. Heating and cooling was carried out at an absolute rate of 1.67° C./min. The dyes employed were: ##STR1##
Cubic Emulsion B was prepared as follows. A kettle was initially filled with 2% bone gel (by volume) in 1.09 liter distilled water at 60° C. The pAg was adjusted to 6.33 by addition of 3N NaCl, and pH was similarly adjusted to 5.54 by addition of 2N sulfuric acid. Silver nitrate (3N) was then added to the kettle while maintaining pAg at 6.33 using 3N NaCl. Flow rates were 3.46 cc/min for 3 minutes of constant flow, 3.46 to 29.87 cc/min for 14 minutes linearly accelerated flow, and 29.87 cc/min for three minutes constant flow, for a total of 20 minutes precipitation. Kettle temperature was then reduced to 40° C., and pAg and pH were adjusted to 7.9I and 2.0, respectively. The resulting emulsion was washed in the same manner as Emulsion A, and the final Emulsion B was made up by adding 20.51 g/mole bone gel and adjusting pAg and pH to 6.93 and 5.6, respectively.
Emulsion C. was formed in the same manner as Emulsion B, except that a mixture of 2.1 N NaCl and 0.9 N NaBr replaced the 3N NaCl used in emulsion grain growth. Similarly, Emulsion D was prepared in the same manner as Emulsion B, except that a mixture of 0.9N NaCl and 2.1 N NaBr replaced the 3N NaCl. Emulsions B, C. and D yielded 0.35, 0.33 and 0.27 micron grains respectively. In emulsions C. and D, the chlorine-bromine content was 70:30 and 30:70, respectively.
Film coatings were prepared as follows. An emulsion layer (E-melt) containing a total of 75 mg/ft 2 of silver and 220 mg/ft 2 of gel was made by mixing the emulsion melt (E) and a dispersion melt (C-melt) together right before coating at 40° C. in a dual melting procedure. Both were coated on a cellulose acetate support at 3.7 cc/ft 2 each at a coating speed of 30 ft/min. The E-melt contained silver and gel (2.89%). The C-melt was prepared containing 1.1 wt. % bone gel, 27.7 wt. % of a magenta coupler dispersion, 0.043 wt. % of 5-bromo-4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene (Bromo-TAI) and 2 wt. % of a surfactant mixture (Triton X-200®:Olin 10G® in a ratio of 3:1). The magenta coupler dispersion comprised 9% of a coupler having the formula: ##STR2## 4.5 % of tris(methylphenyl) phosphoric acid ester, 6 % bone gel, and 0.9% Alkanol-XC®. Triton X-200® is p-tert octylphenoxy ethoxyethyl sodium sulfate. The magenta coupler coverage was 115 mg/ft 2 . Bromo-TAI level was 2.27 g/mole silver. The C-melt contained 2.97 % gel.
The cubic Emulsions B-D were each added to either the C-melt or the E-melt in amounts sufficient to give 8 mole % total silver. The pH of the respective E-melts was 5.9, and pAg was adjusted to 8.2 by a NaBr solution. The pH of the C-melts was 5.1, and pAg of each C-melt was adjusted to either 7.17 or 6.8 by addition of a dilute AgNO 3 solution.
Each emulsion layer was coated on a gel-coated antihalation cellulose acetate support and a 220 mg/ft 2 gelatin protective layer was coated over the emulsion layer and then hardened by 1,1'-[methylenebis(sulfonyl)]-bisethane (1.55 wt. % of total gel).
The resulting emulsion coatings were exposed through a Wratten 9 filter at 1/50 sec 5500K. These were processed to form positive images for 4 minutes in a color developer described in British Journal of Photography Annual, 1982, pages 201-203. Speed was determined at D max 0.3 density. Fog was measured by developing the emulsion coatings to form a negative black and white image for 4 minutes, followed by forming a negative color image. D max and speed loss were calculated after 2 weeks storage at 120° F. in an unexposed state compared to 0° F. stored film. The results are summarized in Table 1 below:
TABLE 1______________________________________Cubic Added Fresh % D.sub.max SpeedEmulsions Into Fog Speed* Loss Loss______________________________________Emulsion B(AgCl)comparison E-melt 0.05 225 32% -31invention C-melt 0.06 242 39% -33Emulsion C(AgClBr 70:30)comparison E-melt 0.10 225 26% -28invention C-melt 0.07 234 21% -26Emulsion D(AgClBr 30:70)comparison E-melt 0.09 224 13% -7invention C-melt 0.10 230 15% -19Emulsion A only None 0.08 223 5% -11______________________________________ *Relative speed in log E multiplied by 100.
The results show that, when the cubic Emulsions B-D are added into the E-melt, no significant speed gain was observed. On the other hand, when each cubic emulsion was added to the C-melt, there was an unexpected increase in speed. The magnitude of the speed depends on the chloride content of the cubic emulsion, as illustrated by the results for Emulsions C. and D. It appeared that the solubility of the AgCl and AgClBr emulsions was greater in the E-melt than in the C-melt. The method of the invention prevented the dissolution of the AgCl or AgClBr, giving rise to better speed enhancement.
Variations on the foregoing procedure showed that changing the size of the tabular grains yields no apparent trend in speed improvement. Similarly, no trend was noted when the cubic grain size was varied in the range of 0.14-0.64 μm, or when different couplers were used. Thus, the speed improvement appears to be a general result of forming the silver salt melt separately from the silver haloiodide melt.
The foregoing results showed that photographic elements according to the invention deteriorated more rapidly than the comparative elements after a period of storage. A color multilayered film created using substantially the same procedure as set forth in this example showed the same speed improvement. In a color negative system, lower speed increases are observed. Examination of the E-melts and coatings of this example in an electron microscope showed that the cubic grains tended to survive and deposit on the faces of the T-grains better when preblended with the C-melt than when preblended with the E-melt.
EXAMPLE 2
Sowinski et al., U.S. Pat. No. 4,656,122, provides no teaching as to how to add fine grains to emulsions. This example examines the method of the present invention using a Lippmann AgBr emulsion added to a tabular grain emulsion E which was prepared by the following procedure. The amount used provided one mole of emulsion.
Silver nitrate (2.75 N) was added to a kettle containing 4.632 g/l NaBr, 0.13% bone gel, and 0.573 liter distilled water at 60° C. at 3.215 cc/min for four minutes. For the last two minutes, salt solution A (2.55 N NaBr+0.2 N KI) was added simultaneously to control pAg 8.75. Then 0.3015 liter of 0 63 % bone gel was added to the kettle and the emulsion was held for 10 minutes. The addition of the silver nitrate solution was continued for 10 minutes while controlling pAg at 8.6 by the salt solution A, followed by an increasing flow rate of the silver nitrate solution from 3.306 to 6.139 cc/min for 10 minutes, from 6.139 to 9.918 cc/min for 10 minutes, and from 9.918 to 13.74 cc/min for 9 minutes. The pAg was then brought to about 8.3 by addition of the silver nitrate solution at 3.306 cc/min for 0.95 minute.
The emulsion was grown further by adding the silver nitrate solution at 6.893 cc/min for 8 minutes and then 3.447 cc/min for 7.3 minutes while controlling pAg at 8.3 by addition of 2.75 N NaBr solution. The emulsion was then cooled to 40° C. and was ultrafiltered as described in the Example 1. 100 cc of distilled water containing 20g bone gel at 40° C. was added to the filtered emulsion. The emulsion pH and pAg were adjusted to 5.6 and 8.2 at 40° C., respectively. The resultant silver bromoiodide emulsion containing 6.2% I comprised tabular grains with median size of 0.45 micrometer, mean thickness of 0.093 micrometer and value of AR/t equal to 52.
This emulsion E was then sensitized as described in the Example 1, except that 0.1 mg HgCl 2 , 250 mg NaCNS, 1,445 mg dye A, 481 mg dye B, 6.91 mg Na 3 Au(S 2 O 3 ) 2 .2H 2 O, 6.67 mg sodium thiosulfate pentahydrate, and 30 mg 3(N-methylsulfonyl) carbamoylethyl benzothiazolium tetrafluoroborate was added to one mole of emulsion, followed by 25 minutes digestion at 70° C.
Film coatings were prepared and evaluated as described in the Example 1 except that 0.08 micrometer AgBr Lippmann emulsion was used in place of cubic emulsions B, C, D. 5 or 10 mg per sq.ft. were coated with the tabular grains at 75 mg/sq.ft. total silver coverage. The results are shown in Table 2 below:
TABLE 2______________________________________AgBr Lippmann Added Fresh % D.sub.max SpeedEmulsions Into Fog Speed Loss Loss______________________________________ 5 mg/sq. ft.AgBr Lippmanncomparison E-melt 0.08 195 28% -4invention C-melt 0.05 189 14% 210 mg/sq. ft.AgBr Lippmanncomparison E-melt 0.06 189 32% -3invention C-melt 0.05 190 4% 14Emulsion E only 0.08 182 15% 6______________________________________
The fresh and keeping results suggested that it didn't matter how the Lippmann AgBr emulsion was added in terms of the fresh speed as taught by the Sowinski patent, but adding it to the C-melt provided better keeping. Again, the difference we see here from the AgBr emulsion compared to more soluble AgCl or AgClBr arise from differences in solubilities.
While several embodiments of the invention have been described, it will be understood that it is capable of further modifications, and this application is intended to cover any variations, uses, or adaptations of the invention, following in general the principles of the invention and including such departures from the present disclosure as to come within knowledge or customary practice in the art to which the invention pertains, and as may be applied to the essential features hereinbefore set forth and falling within the scope of the invention or the limits of the appended claims. | A method for forming a photographic element includes steps of heating an emulsion containing grains of a radiation sensitive silver haloiodide to form a first melt, heating an emulsion containing grains of a silver salt effective to enhance the photographic properties of the silver haloiodide emulsion to form a second melt, and coating the first and second melts onto a photographic support to form an image recording layer. The silver salt grains are substantially insensitive to radiation at wavelengths at which said silver haloiodide grains are sensitive. The coating step is preferably carried out by blending the first and second melts together, then immediately coating the silver haloiodide emulsion onto the support. In a preferred embodiment, the silver salt is essentially silver chloride in the form of relatively fine cubic grains, and the silver haloiodide is in the form of tabular grains larger than the cubic grains. The foregoing procedure unexpectedly improves the speed of the resulting photographic element. For color reversal photographic elements, the melt containing the fine silver salt grains is conveniently the coupler melt. | 8 |
BACKGROUND OF THE INVENTION
The present invention relates to medical instrumentation apparatus, more particularly it relates to an improved delta modulation circuit for use in such medical instrumentation apparatus.
In the art of medical instrumentation, wherein sensing electrodes are attached to the patient to monitor certain body phenomena, it has been found necessary to provide a measure of isolation between the patient and the measuring, recording, and/or display apparatus, to prevent an inadvertent shock to or electrocution of the patient in the event of a malfunction of the measuring, recording, or display apparatus. In one form, that isolation circuitry has involved the use of a delta modulator to provide signal conversion.
In the conventional delta modulator, a variable voltage signal is compared with a quantized previous signal sample at a predetermined sampling rate. This produces a digitized output signal representative of the difference between the magnitude of the variable input signal and the previous sample. In such conventional delta modulators, a positive or a negative voltage reference signal is applied, depending upon the comparison of the previous signal with the present signal. The reference signal is applied through the sampling period to an integrator circuit to provide the quantized last signal sample. While such delta modulators have been used in systems in the past, the conventional delta modulator system as described includes a number of disadvantages which tend to limit the accuracy of such a system. One such deficiency is a voltage and current offset characteristic of the integrator. Such offset tends to produce an incorrect magnitude of the quantized reference signal. Second a separate reference voltage source is used for the positive and negative voltages. There is frequently a difference in the magnitude of the positive and negative reference voltage sources and this difference is also reflected in an incorrect value to the quantized reference signal. Because the signal is quantized by an integrator, the quantized signal is a time-dependent function. Accordingly, an additional deficiency is experienced in the presence of irregularities in the clocking signal. A further limitation which can result in an error is due to the finite time required to change the polarity of the quantized reference signal. Sine the quantizer is an integration circuit, a finite integrating time is of necessity a limiting factor on the sampling rate. When the input variable signal changes at a rate faster than the sampling rate, an inaccuracy in the resulting signal follows.
SUMMARY OF THE INVENTION
It is, accordingly, an object of the present invention to provide an improved delta modulator which avoids the foregoing deficiencies.
It is another object of the present invention to provide an improved coupling system for medical instrumentation apparatus.
In accomplishing these and other objectives, there has been provided in accordance with the present invention an improved delta modulation circuit wherein a variable input voltage is compared with a quantized previous signal sample, resulting in a digitized output. The digitized output of the comparison controls the selective operation of a switching control circuit which, in turn, is clocked at a predetermined rate. The switching control circuit selectively applies a positive or a negative reference signal to the input of the quantizer from a common reference signal source. A quantum charge is derived from the signal reference source then, through selective switching, that quantized charge is transferred in a positive or a negative direction to the input of a quantized charge memory device.
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the present invention may be had from the following detailed description when read in the light of the accompanying drawings in which:
FIG. 1 is a schematic block diagram of a previously known delta modulator.
FIG. 2 is a schematic block diagram of a delta modulator in accordance with the present invention.
DETAILED DESCRIPTION
Referring now to the drawings in more detail, there is shown, in FIG. 1, a conventional delta modulator circuit wherein an input voltage signal is applied to an input terminal 2 connected to one input of a comparator 4. A quantized previous signal sample is applied to the second input terminal of the comparator 4. The output of the comparator 4 is a logical "high" or a logical "low" depending upon the relative magnitudes of the two input signals. That output signal from the comparator 4 is connected to an output terminal 6, the output signal for the loop. The output signal for the comparator 4 is also applied as control signal for a plus or minus reference voltage control unit 8.
The reference voltage control unit 8 comprises a switching logic which is activated by a clock signal applied to an input terminal 10. The clock signal applied to the input terminal 10 determines the frequency at which reference voltages are sampled. A positive reference voltage source is represented by a battery 12 while the negative reference voltage source is represented by a battery 14. These batteries 12 and 14 are connected, respectively, between ground and corresponding input terminals to the control unit 8. The output of the control unit 8 is connected to the input of an integration circuit which includes an integrator resistor 16, an amplifier 18, and a feedback capacitor 20. The output of the integrator circuits comprises a quantized previous signal sample which is applied to the second input terminal of the comparator 4. In the modulator illustrated in FIG. 1, the output of the comparator 4 as noted, is a logical "high" or a logical "low" resulting from each successive comparison. The logical state of the output of the comparator 4, when applied to the input of the reference voltage control unit 8, determines whether the positive reference voltage 12 or the negative reference voltage 14 is to be applied to the input of the integrator. The clock signal applied to the input terminal 10 determines the sampling period for whichever of the two reference voltages are to be applied to the integrator. The timed integration of the reference signal by the integrator provides a quantized output signal representing the last sample, which is, in turn, an input terminal of the comparator 4.
Since the clock signal determines the sampling period for the integrator, it may be seen that the size of the quantum signal is a function of the size of the reference voltage and the period of the clock signal. If there is an irregularity in the period of the clock signal a corresponding variation will appear in the quantized last signal sample. Similarly if there is a disparity in the actual value between the positive and negative reference voltage sources, there will be a corresponding disparity in the magnitude of the positive and negative quantized reference signals. Either of these disparities will produce a corresponding error or irregularity in the digitized output signal applied to the terminal 6. Again, since the quantized signal sample is the result of a time-integral function, there are errors introduced as a result of the finite time required to change the polarity of the reference voltage signal.
The foregoing weaknesses of the conventional delta modulators shown in FIG. 1 are overcome by the improved delta modulator circuit shown in FIG. 2. In FIG. 2 the variable input signal is applied to an input terminal 20 connected to one input of a comparator 22. In an exemplary structure constructed in accordance with the present invention, it was found that an integrated circuit unit identified as LM311 produced by National Semiconductor is suitable for use as the comparator 22. A second input to the comparator 22 has a quantized previous signal sample applied thereto, as will be shown hereinafter. The output of the comparator 22 is connected to an output terminal 24 and to the input of a switching control logic unit 26. The switching control logic unit 26 is keyed by a clock signal of predetermined frequency connected to the clock input terminal 28. While the frequency of the clock signal may be of any frequency suitable to the application, in an exemplary structure constructed in accordance with the present invention, the clock signal had a frequency of 32 KH Z . The switching control logic unit 26 is connected to control the selective operation of a reference voltage switching network 30.
The reference voltage switching network 30 includes a DC reference voltage source represented by a battery 32. The battery 32 has the positive terminal thereof connected to a fixed contact of a first switch member 34, while the negative contact of the battery 32 is connected to ground and to a fixed contact of a second switch member 36. The switches 34 and 36 are effectively ganged together for simultaneous operation under the control of the switching control logic unit 26. These switches are represented as mechanical single-pole, single throw switches. It will be recognized, however, that in a preferred embodiment, the switches 34 and 36 are, in fact, solid state switches. The movable contact of the switch 34 is connected to a first side of a capacitor 38 while the other side of the capacitor is connected to the movable contact of the switch member 36. The first side of the capacitor 38 is connected to a first fixed contact of a third switch 40 and to a first fixed contact of a fourth switch 42. The second side of the capacitor 38 is connected to a second fixed contact of the switch 40 and to a second fixed contact of the switch member 42. The movable contact of the switch member 42 is connected to ground. The movable contact of the switch member 40 is connected to the input of a memory unit 44. The switch members 40 and 42 are represented in the drawings as mechanical single-pole, double-throw switches while in a preferred embodiment these switch members are also solid state switching devices.
The memory unit 44 includes an operational amplifier 46 and a memory capacitor 48. The memory capacitor 48 is connected directly across the operational amplifier 46, being connected between the input and the output terminals thereof. In a exemplary structure constructed in accordance with the present invention, an integrated circuit unit identified as LF356, produced by National Semiconductor, has been found to be suitable for use as the operational amplifier 46. The output terminal of the memory unit 44 is connected to the second input terminal of the comparator 22.
The comparator 22 in the circuit shown in FIG. 2 operates in substantially the same manner as the comparator in the conventional delta modulator shown in FIG. 1. That is, a variable input voltage is compared with a quantized previous signal sample on a periodic basis to produce a digitized output signal at the output terminal 24. The digitized output signal from the comparator 22 is also applied to an input terminal of the switching control logic unit 26. As noted before, the switching control logic unit 26 controls the actuation of the several switches in the reference voltage switching network 30. A relatively high frequency clock signal, applied to the input terminal 28 of the switching control logic unit 26, controls the timing of the actuation of the several switches in the network 30. At the beginning of each clock cycle applied to the switching control logic unit 26, the switches 34 and 36 are closed for a predetermined timed interval. That time interval is sufficient to allow the capacitor 38 to be charged substantially to the voltage of the reference voltage source 32. Under the control of the unit 26, the switches 34 and 36 are then opened. The switches 40 and 42 are both in a normally opened condition with respect to both sets of fixed contacts. Again under the control of the switching control logic unit 26, the switches 40 and 42 are selectively closed on one or the other of the two corresponding fixed contacts. The direction of the closure of the two switches 40 and 42 is determined by the nature of the signal applied during that clock cycle from the output of the comparator 22. The closure of the switches 40 and 42 causes the charge on the capacitor 38 to be algebraically summed with the charge on the capacitor 48 in the memory unit 44. The memory unit is an inverting stage, therefore a positive charge input will result in an output voltage shift in the negative direction and vice-versa. If the digital output of the comparator indicates that the input signal applied to the input terminal 20 is lower than the previous signal sample applied to the other input terminal of the comparator 22, the signal applied to the input of a switching control unit 26 will cause the switches 40 and 42 to be closed to their upper contacts, respectively.
The closure of those switches to their respective upper contacts causes the charge on the capacitor 38 to be added to the charge on the capacitor 48 in a positive direction. This, in turn, causes the output of the memory unit 44 to shift by one quantum of voltage step in the negative direction. If, on the other hand, the output of the comparator 22 is such as to indicate that the input signal is larger than the previous signal sample, the switching control logic unit 26 would cause the switches 40 and 42 to be closed on their respective lower fixed contacts. That arrangement causes the charge on the capacitor 38 to be applied to the input of the memory unit in an inverse or negative direction, thereby subtracting that charge from the charge on the capacitor 48 this causes the output of the memory unit 44 to shift by one quantum voltage step in the positive direction.
The charge increments, whether positive or negative, are derived from the same reference voltage source, using the same quantum capacitor 38. This arrangement eliminates the potential for differences between the positive and negative reference increments such as may occur in the conventional delta modulator circuits such as is seen in FIG. 1. With this quantum charge being established on a common capacitor and being derived from the common reference voltage source, there can be no difference in magnitude between the positive and negative increments. Thus one potential source of inaccuracies in the output signal, as distinguished from the conventional delta modulator, has been eliminated by the structure of the present invention.
The charge time of the capacitor 38 from the battery 32 is extremely short. Similarly the time required to transfer the charge on the capacitor 38 to the the capacitor 48 is also very small. So long as these charge times are small relative to the period determined by the clock cycles, the magnitude of the charge increments are independent of a time function. Instead, the magnitude of the charge increments is a function of the voltage of the reference source 32 and the ratio of the capacitors 38 and 48. In the exemplary embodiment constructed in accordance with the present invention, the voltage reference source 32 provided a five volt reference signal, the ratio of the capacitances of the capacitors 48 and 38 was scaled such that there was produced a quantum differential in the reference signal of 20 millivolts per clock cycle. It will be appreciated of course that the magnitude of the increments can be made of any desired value by suitably scaling the parameters of the circuit and the size of the reference voltage source signal. Since the quantized reference signal increments are independent of a time function, the time related errors mentioned in connection with the conventional delta modulator circuit are effectively eliminated.
While the present invention has been described in terms of discrete components, it will be appreciated that the structure of the apparatus is such as may be embodied in an integrated circuit chip module.
Thus there has been provided in accordance with the present invention, an improved delta modulator which features a high accuracy of output and in which time related or polarity related inaccuracies are eliminated. | A delta modulation circuit features a variable input voltage which is compared periodically with a quantized previous signal sample, resulting in a digitized output. The digitized output of the comparison controls the selective operation of a switching control circuit which, in turn, is clocked at a predetermined rate. The switching control circuit selectively applies a positive or a negative reference signal to the input of the quantizer from a common voltage reference source. A quantum charge is derived from the signal reference source then, through selective switching, that quantized charge is transferred in a positive or a negative direction to the input of a quantized charge memory device, resulting in the quantized last signal sample. | 7 |
BACKGROUND OF THE INVENTION
The present invention relates to a thermoforming station including a quick cooling system for quickly cooling the molded products.
The invention also relates to a thermoforming method carried out in the inventive thermoforming station.
More specifically, the present invention relates to a thermoforming station of the type in which a sheet-like plastics material (supplied in plate or coil form) is molded within a bell-shaped molting element arranged at a location opposite to the mold supporting element, thereby said bell element can be closed on the latter.
As is known, in such a thermoforming station, the sheet-like plastics material is brought to the plasticizing temperature thereof and then being locked, at a set molding position, by closing said bell element against the perimetrical edge of the plastics material itself. Then, a vacuum or negative pressure is provided inside said bell element, so as to draw the plastics material into said bell element, to provide the plastics material a pre-stretched ball shape. Under the thus formed ball a mold element is then arranged, while reversing the vacuum direction thereby causing the plastics material to be pressed and adhere to the mold, for the molding operation proper.
Then, the molded plastics material is allowed to cool, the bell element being held in a closed condition to hold the molded article being cooled on the mold. Thus, suitcase shells, motor vehicle components, refrigerator cells and doors, bath furniture pieces and the like are made.
In this prior molding method, the cooling operation represents the most critical step since the outer surface of the molded articles must be cooled as evenly as possible in order to prevent inner stresses from undesirably deforming the molded article.
Moreover, the cooling step represents the longest step of the method and, in order to increase the yield, the cooling time should be as short as possible.
On the other hand, the achievement of the above two objectives is hindered by the provision of the mentioned bell element which, as stated, during the cooling period must be held in a closed condition on the plastics material applied on the mold.
For providing a ventilation through the plastics material surface facing the inside of the bell element, the latter is conventionally provided with a plurality of large openings which can be tightly closed during the under vacuum-operations. Inside the bell element is moreover conventionally provided a channel pattern for ejecting pressurized air jets against the surface of the plastics material to be cooled. For this reason, the air outlet openings of the bell element must have a size larger than that of the inlet openings thereby the bell element will be provided with a perforated construction having a lot of smaller and larger openings. The number of these openings, in particular, will depend on the cooling efficiency to be achieved. In this connection, however, it should be apparent that the number of said openings cannot be increased to any desired value, since for a very large number of openings, it would be required to design a lot of expensive sealing elements requiring, furthermore, an intensive maintenance (also considering the comparatively high operating temperature of the bell element).
SUMMARY OF THE INVENTION
Accordingly, the aim of the present invention is to provide a thermoforming station of the above mentioned type, which is specifically adapted to cool in a very quick manner the molded plastics material or articles.
Within the scope of the above mentioned aim, a main object of the present invention is to provide such a thermoforming station allowing to carry out therein a molding process requiring a small molding operating time while providing molded articles free of any inner stresses due to a uneven cooling of the surfaces of the molded articles.
Another object of the present invention is to provide such a thermoforming station allowing an efficient circulation of air through the plastics material arranged inside the thermoforming bell element, while allowing said thermoforming bell element to have a comparatively simple construction.
Yet another object of the present invention is to provide a thermoforming station of the above mentioned type which, differently from conventional thermoforming stations requires a very reduced maintenance, while providing a cooling system very resistant against wear and high operating temperatures.
Yet another object of the present invention is to provide such a thermoforming station allowing an improved thermoforming method to be quickly carried out therein.
According to one aspect of the present invention, the above mentioned aim and objects, as well as yet other objects, which will become more apparent hereinafter, are achieved by a thermoforming station for molding a sheet-like plastics material, of the type comprising a mold and a bell element for closing said mold, and being essentially characterized in that said bell element comprises a disassemblable or openable construction adapted to provide a lot of ventilating and cooling openings for ventilating and cooling said plastics material arranged in said thermoforming station.
According to further features of the present invention, said station is moreover provided with driving means for opening said bell element during the cooling of said plastics material and closing said bell element during the hot molding operations of said plastics material. Said driving means are moreover designed for holding said plastics material on said mold, even with the bell element in an open condition for the cooling operations.
The thermoforming station according to the invention is further characterized in that said bell element comprises a side wall and a movable panel which can be closed as a cover on said side wall.
Said driving means for opening and closing said bell element comprise, in turn, a cylinder-piston assembly which is connected, on a side, to said movable panel and, on the other side, to said wall.
According to yet further features of the invention, said thermoforming station comprises moreover side guide elements, preferably of a pinion-rack type, provided for sliding on sliding column and adapted to center the movement of said movable panel and wall of said bell element with respect to one another and to the mold. Means for locking the plastics material on the mold rigid with the edge of said side wall of said bell element, opposite to the engagement edge thereof with said movable panel, are moreover provided.
The thermoforming station according to the present invention is furthermore characterized in that it comprises driving cylinders for raising or opening, in a lockable manner, said wall of said bell element. A fan assembly for providing and orienting air jets inside said bell element, as it is opened by at least one of the mentioned opening driving means is moreover provided.
According to yet further features of the thermoforming station according to the present invention, said thermoforming station is moreover provided with additional ventilating and cooling openings, formed through said side walls of said bell element. On said side wall are moreover provided a plurality of driving cylinders for driving said side wall with respect to said mold, as well as a pressurized air channel arranged inside said bell element and aiding for cooling said plastics material, and a reduction assembly driven by said cylinders and cooperating with the reduction assembly born by said bell element, for holding the plastics material on the mold.
The thermoforming method for thermoforming a sheet-like plastics material by using the inventive thermoforming station, which method also constituted a main aspect of the present invention, is characterized essentially by the fact that said method comprises a step of forming ventilating and cooling slots for said plastics material, by disassembling or opening said bell element, which is held clamped on said plastics material to hold the latter at a fixed position on the mold.
The thermoforming method according to the invention is moreover characterized in that it provides to form said openings by raising or detaching said movable panel from said side wall of said bell element. Further openings are formed by raising or detaching said side wall from said reduction assembly clamped on said plastics material adhering to said mold.
With respect to prior thermoforming stations, the thermoforming station of the invention provides the advantage of allowing a quicker and much more efficient cooling of the molded plastics material. Thus, the overall thermoforming operating time can be reduced up to 50% with respect to a conventional thermoforming time, i.e. the thermoforming time of prior apparatus, to provide an evenly molded product free of any inner stresses due to an excessively quick cooling.
Moreover, the thermoforming station according to the invention, being provided with a bell element free of windows, has a much more simple and reliable construction with comparatively low making costs and maintenance requirements.
BRIEF DESCRIPTION OF THE DRAWINGS
The above mentioned and yet other characteristics, objects and advantages of the invention will become more apparent hereinafter from the following detailed disclosure of preferred embodiments of the inventive thermoforming station, which have been illustrated, by way of a merely illustrative example, in the figures of the accompanying drawings, where:
FIG. 1 shows a first embodiment of the thermoforming station according to the invention, in a cross-sectional view through a vertical plane;
FIG. 2 shows the thermoforming station of FIG. 1, during the thermoforming method starting step;
FIG. 3 shows the thermoforming station of FIG. 2, during a drawing method step in which a plastics material is drawn inside a bell element;
FIG. 4 shows the thermoforming station of FIG. 3 during a subsequent plastics material drawing step;
FIG. 5 shows a cooling step performed in the thermoforming station of FIG. 4;
FIG. 6 shows a further cooling step performed according to a second embodiment of the inventive thermoforming station;
FIG. 7 shows a further cooling step performed according to a third modified embodiment of the inventive thermoforming station; and
FIG. 8 is a perspective view showing, in exploded form, the thermoforming station of FIG. 6 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The thermoforming station shown in FIG. 1 essentially comprises a movable panel 1 supporting a mold 2 which is closed at the top thereof by a bell construction or element 6 - 7 , which will be disclosed in a more detailed manner hereinafter. In this connection, however, it should be pointed out that the mutual positions of the above mentioned parts could be different from the shown positions and, in particular, the mold 1 could be arranged in a reversed position from the shown position (the mold bearing panel 1 at the top and the bell element or construction 6 - 7 at the bottom).
Said bell element of the inventive thermoforming station comprises a side wall 6 , patterned as the mold supporting panel 1 plan, and being closed at the top thereof by a closing cover 7 , which also represents the movable panel for driving the bell element. To that end, the cover 7 comprises a plurality of cylinders 13 , for raising the movable panel 7 and side wall 6 of the bell element.
As is clearly shown in FIG. 5, the movable panel 7 can be raised from the wall 6 , while being held rigid therewith, in order to provide a large peripheral window 19 . To that end, the movable panel 7 is provided with a plurality of driving cylinders 12 , the pistons 11 of which connect the panel 7 to the edge portion of the wall 6 thereon said panel 7 must be closed. More specifically, the body of the cylinder 12 is anchored to the movable panel 7 , whereas the piston 11 thereof has its free end portion coupled to the wall 6 of the bell element. Thus, as the cylinder 12 is driven, the piston 11 thereof will be extended, thereby raising or detaching the cover 7 from the sidewall 6 .
An assembly of guide side elements 14 and 15 is moreover slidingly provided on corresponding vertical columns 16 , preferably of a pinion-rack type, for perfectly centering the movement of the movable panel 7 and, respectively, of the side wall 6 with respect to one another and the mold 2 .
A plurality of fans 8 for generating and orienting a plurality of air jets 20 inside said bell element are moreover coupled to said panel 7 , and provided for operating in the raised position of said panel 7 from said wall 6 , through the mentioned peripheral window 19 .
On the edge of said sidewall 6 opposite to the movable panel 7 engagement edge thereof, is provided a reduction assembly 4 designed for cooperating with a corresponding reduction assembly 5 , which can be driven by pistons 22 , thereby holding the edge portion of a sheet-like plastics material 3 (in a plate or coil form) at a desired molding position (FIG. 1 ).
Advantageously (see FIG. 6) the side wall 6 of the bell element can be raised, with respect to the reduction assembly 4 held pressed on the plastics material 3 , by a plurality of driving cylinders 17 , substantially corresponding to the above disclosed cylinders 12 . Even in this case, the cylinder piston rod is connected to the reduction assembly 4 , which is held in its set position. The body of the cylinders 17 , on the contrary, is connected to the side wall 6 of the bell element, thereby causing said side wall to be moved away from the reduction assembly 4 . Thus, during the cooling step, a further ventilating peripheral opening 21 can be formed. The cooling of the molded plastics material is moreover improved owing to the provision of a conventional pressurized air channel pattern 9 .
In the modified embodiment shown in FIG. 7, the thermoforming station of FIG. 6 has been moreover provided with a plurality of fans 8 arranged at a level of corresponding ports 10 in turn provided through side wall 6 of the bell element.
At the start of the molding method, the sheet-like plastics material 3 , already brought to its plasticizing temperature, is arranged between the bell element 6 - 7 and the movable panel 1 supporting the mold 2 (FIG. 2 ). Then (FIG. 3) the reduction assemblies 4 and 5 are pressed against the perimeter of the plastics material 3 , thereby locking it at its proper molding position, then, inside the bell element 6 - 7 air is sucked (in the direction of the arrows of FIG. 3) for forming a pre-stretching ball 18 of the plastics material 3 . At this time, the mold bearing or supporting panel 1 is closed on the bell element 6 - 7 , and air is further sucked in a direction opposite to the previous air sucking direction (with a possible pressurizing of the bell element, see the arrows in FIG. 4 ), thereby drawing the plastics material against the mold 2 for properly molding it (see FIG. 1 ). Then, the molded plastics material cooling step will be started, said cooling step being performed through the reduction assemblies 4 and 5 holding the plastics material 3 in its set position on the mold 2 .
In particular, the mentioned cooling is performed, according to the invention, by raising or detaching the movable panel 7 from the sidewall 6 of the bell element (see FIG. 5 ), thereby providing a large perimetrical opening 19 therethrough the fans 8 will eject air jets 20 inside the bell element and through the outer surface of the plastics material or molded article 3 . In this connection it should be pointed out that the hot air streams will exit through the same opening 19 (see the thickened arrows of FIG. 3 ).
According to the modified embodiment of FIG. 6, a like opening 21 can be advantageously formed also in the bottom of the bell element, by raising or detaching said sidewall 6 thereof from the reduction assembly 4 , while holding it in a gripping relationship on the plastics material 3 .
A further improved cooling, moreover, can be provided by the fans 8 which, in the modified embodiment shown in FIG. 7, are arranged at the level of the mentioned ports provided through the side wall 6 of the bell element.
Thus, owing to the invention (which, in the illustrated embodiments provides to form large openings 19 , 21 at the hot regions inside the bell element), the cooling time can be reduced up to a 50% rate of the cooling time usually provided for cooling the molded articles in prior thermoforming stations. Thus, for example, for molding a home refrigerator cell starting from a sheet-like plastics material (supplied in pate or coil form), having a thickness of 4.5 mm, the thermoforming temperature will be about 140° C., and the plastics material would be cooled to at least 70° C. (a thermal gradient or jump of at least 70° C.). By using conventional thermoforming bells, i.e. fixed thermoforming bells, this cooling would be conventionally achieved in a time of 20-30 seconds. On the contrary, by using the thermoforming station according to the present invention, the mentioned temperature differential of 70° C. would be achieved in a time of 10-15 seconds, owing to the possibility of opening the bell to provide large cooled air circulation openings.
While the invention has been disclosed with reference to preferred embodiments thereof, it should be apparent that the disclosed embodiment are susceptible to several modifications and variations. Thus, for example, the bell element could be disassembled into portions of the construction thereof different from the disclosed portions thereby defining openings at different sections of said bell. Moreover, the driving means for opening or disassembling the bell could be different from the disclosed driving means, as well as the guide means and the number and arrangements of the disclosed fans. | A thermoforming station and method for molding a sheet-like plastics material provide to use a bell element including a cover which can be opened on a sidewall in order to provide a large opening for ventilating and cooling the molded plastics material thereby reducing up to 50% the time conventionally required for making a thermoformed evenly cooled product. | 1 |
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation of application Ser. No. 906,434 filed May 17, 1978 now abandoned which in turn is a CIP of U.S. Ser. No. 846,355 filed Oct. 28, 1977 now abandoned.
BACKGROUND OF INVENTION
(a) Field of the Invention
This invention relates to fabrics as used in the dryer sections of paper making machines.
(b) Description of Prior Art
In the manufacture of paper on a Fourdrinier paper making machine, for example, an aqueous suspension of cellulose fibres, comprising one part or less fibres in 99 parts or more of water by weight, is flowed on to an endless rotating forming screen woven of metal or synthetic filaments. As this belt, or forming fabric or "wire", as it is called, passes over water extraction devices such as table rolls, drainage foils and suction boxes, the water content of the suspension supported on the fabric is reduced to about 80 to 85 percent.
The thin web of fibres, now self supporting, is removed from the forming fabric and passes to a series of one or more press sections where it is deposited on other endless belts of relatively thick fabric, one or both surfaces of which may be composed of a needled bat of synthetic or natural fibres. These belts, called wet felts carry the web through the nips of press rolls where more of the water remaining in the web is squeezed into the absorbent felts until the water content is lowered to about 65% at which point it is not generally practical to attempt further water removal by direct extraction such as with pressure or vacuum.
The web of paper is then passed to the dryer section of the machine where the remainder of the water is removed by an evaporation process accelerated by the application of heat. The dryer section consists of a number of large, hollow cast iron or steel cylinders over which the paper web passes in a serpentine fashion. The cylinders are rotated synchronously to facilitate the passage of the web. Heat is supplied by steam condensing inside each cylinder and the web is held in intimate contact with portions of the heated surfaces of the dryer cylinders by the dryer fabrics.
To provide sufficient drying capacity a newsprint dryer section, for example, may consist of about 50 dryer cylinders each about 5 feet in diameter and set up in an upper and lower tier in four or five individual subsections.
In order to appreciate the magnitude of the dryer section of a modern paper making machine, the overall size may be about 200 feet long, up to 40 feet wide and up to 40 feet high. The paper web may pass through the dryer section at speeds up to 3000 feet per minute so that any part of the web may only remain in the dryer section for as little as 15 seconds during which time the web will be reduced to a normally dry sheet of paper.
The dryer fabrics serve to hold the paper web against the heated surfaces of the rotating dryer cylinders to promote more effective heat transfer to the web by partially eliminating a heat insulating layer of air which adheres to the surface of the cylinders. The drier fabrics also serve to prevent the paper web from wrinkling.
In the conventional dryer section there is an upper and a lower dryer fabric. The upper fabric wraps around and holds the paper web against the upper peripheries of the upper dryer cylinders while the lower fabric wraps around and holds the paper web against the lower peripheries of the lower dryer cylinders. The fabrics are guided by intermediate fabric rolls placed between the cylinders.
Dryer fabrics operate in a particularly adverse environment in which they are alternately exposed to hot and wet and hot and dry conditions. They must be flexible in the machine direction so that they can bend around the felt rolls easily. They must have good dimensional stability and durability under the conditions of tension, temperature and humidity which prevail in the dryer section of a paper machine. Generally, dryer fabrics are woven from either natural or synthetic yarns to form a relatively bulky fabric that will have good absorbent characteristics and high porosity to enhance removal of moisture from the web of paper. To attain these results the yarns are woven closely together and sometimes in several plies to form a comparatively impermeable fabric. To decrease permeability further sometimes bulky staple fibre yarns, some containing asbestos, are woven in. These fabrics thus exhibit an undesirable tendency to hold sufficient water to rewet the sheet. They also become increasingly difficult to clean of various foreign substances such as sizing agents, clay-like fillers and resins, gums, waxes and pitch and the fabric becomes plugged up so that it has to be cleaned frequently or repaced.
Dryer fabrics are usually woven with approximately 100% warp fill, as shown in the drawings of this application and as is well known to those skilled in the art. Warp fill is defined as the amount of warp in a given space relative to the total space considered. Warp fill can be over 100% when there are more warp strands jammed into the available space than the space can dimensionally accommodate in a single plane. Fabrics having a nominal warp fill of approximately 100% will generally have an actual calculated warp fill of from 80% to 125% as is the fabric of this invention. Values over 100% are brought about by crowding and lateral undulation of the warp strands.
Permeability is an important characteristic of a dryer fabric and is a measure of its air passage capability. A low permeability fabric will resist the passage of air and tend to absorb vapour whereas a high permeability fabric will allow free passage of air and vapour.
As indicated previously dryer fabrics were conventionally made from cotton or wool and sometimes contained asbestos fibres. With the development of synthetic yarn materials the conventional fabrics are gradually being replaced by fabrics containing synthetic yarns. These may be woven in simple or in very complex weaves in two or three plies or more of either relatively large diameter monofilament yarn or of multifilament yarns spun from many small diameter filaments.
Of the new synthetic yarns monofilaments are preferred because the resultant fabric has increased running life, is easy to clean, does not shed fibre and does not carry excessive moisture. During the part of the cycle when the fabric is in contact with the sheet over a dryer cylinder, low moisture content and high permeability enhance transfer of heat to the web. Also, the high permeability of the fabric can have a beneficial effect on ventilation of the dryer pockets, producing a more even moisture profile in the web. However, the high permeability of fabrics made from all-monofilament yarns in some cases is a disadvantage as it causes excessive air movement in dryer pockets which results in sheet flutter. This problem increases with machine speed and a point is soon reached when the flutter, particularly in the first and second dryer sections where the web is wet and weak, is violent enough to cause it to break.
The effect of fabric permeability on dryer pocket ventilation and sheet flutter has been described by Race, Wheeldon, et al (Tappi, July 1968 Vol. 51 No. 7) and they have shown that air movement in dryer pockets is influenced by permeability rather than by the surface roughness of the fabric as was previously supposed. Air movement in dryer pockets is induced by the fact that a moving fabric carries with it layers of air. At the surface of the fabric the velocity of the air layer is the same as that of the fabric and as the distance from the surface of the fabric increases the velocity of the air decreases. When the fabric wraps around a roll, the layer of air on the inside is trapped in the nip between the roll and the fabric and, if the fabric is sufficiently permeable, the air from the inside is pumped through, joins the air stream on the outside of the fabric and the combined velocity of the two streams is greater than the speed of the fabric. As the fabric passes around the roll the layers of air on the outside tend to be thrown outward by centrifugal force generating tangential air movement. This results in a large mass of air moving laterally out of the pockets when high permeability fabrics are used on high speed machines.
The Race, Wheeldon et al experiments show that as fabric speed increases, the air which is pumped through the fabric by the felt rolls of the dryer increases in velocity, particularly at speeds above 1500 r.p.m. They also show that as fabric permeability is reduced, the amount of air pumped into the dryer pockets is correspondingly reduced. Thus at low speeds a dryer fabric with high permeability can be tolerated and, in fact, is useful in achieving high drying rates, but at high speeds, particularly in the first or second dryer sections, it is necessary to have low permeability fabrics in the range of 50 to 200 cu.ft./min./sq.ft. Thus on high speed machines it is often not practical to take advantage of the easy to clean characteristic of monofilament fabrics because of their inherent high permeability.
"Permeability" is usually expressed by the number of cubic feet of air per minute passing through a square foot of the fabric when the pressure drop across it is 0.5 inches of water. One instrument used to measure air permeability is a Frazier Air Permeometer.
In this instrument air is drawn by a variable speed run through a 1 square inch section of fabric to be tested then through upper and lower chambers joined by one of a set of replaceable orifices calibrated for measuring volume by pressure differential. The speed of the fan is increased until the upper chamber reaches a vacuum of 0.5 inches of water as indicated on a manometer. The vacuum, in inches of water, in the lower chamber is then read off another interconnected monometer and this value is applied to a reference graph to convert the reading to cubic feet of air per minute per square foot of fabric.
While in the conventional dryer system, the problem of sheet flutter may be overcome by using a dryer fabric having low permeability, another method of alleviating this problem is known as the single fabric dryer system. In this method, a single dryer fabric is used to guide the web of paper in serpentine fashion through the dryer sections of the paper machine. The paper, for example, is introduced under the fabric at the first upper cylinder and passes substantially in contact with the fabric all through a dryer section so that it lies between the fabric and the cylinders in the upper tier and outside the fabric around the cylinders in the lower tier.
The main advantage of the single fabric dryer system is that the web of paper is partially supported by the fabric as it passes between the tiers of dryer cylinders and sheet flutter is thereby reduced or may be entirely eliminated.
Other important advantages of the single fabric dryer system include reduction of dryer fabric costs and elimination of felt rolls and one set of stretch and guide rolls which are no longer required. Also, since the lower tier of cylinders is not encumbered by a separate lower dryer felt, the waste paper from paper breaks, or "broke" as it is called, may be removed more easily.
A disadvantage of the single fabric system is that when it is applied to existing dryer sections in which all the dryer cylinders are the same size and are driven at the same rotational speed by an interconnected set of gears, the conventional monofilament fabric having a high modulus of elasticity, is quite inextensible and will try to force the upper cylinders, which have a larger effective diameter due to the layer of paper, to turn at a lower rotational speed. This braking action of the cylinders by force tending to stretch the fabric, produces considerable stress on the drive train and even when the web of paper is fairly thin, the stress has been sufficient to cause abnormal wear of the gear teeth and bearings and in some cases structural failure.
The stretch of the fabric, called fabric draw, caused by the difference in fabric path lengths over the cylinders is within the elastic range of the fabric and is proportional to the thickness of the web of paper. The stress, expressed in terms of torque, on the dryer cylinder gears, is proportional to the product of the paper thickness and the modulus of elasticity of the fabric. As a practical example, in a single fabric dryer section where the paper web is only 0.012 inches thick the calculated torque developed at the drive gear of an upper cylinder will amount to 3000 ft.-lbs. From this it will be apparent that the problem of gear wear and structural failure will be significantly alleviated by using a fabric having a lower modulus of elasticity so that it stretches more easily and can absorb the stress developed by differentials in dryer cylinder diameter due to paper thickness.
While the above example illustrates the degree of stress that can be developed by a relatively thin web of paper, it will be appreciated that differences in dryer cylinder diameters caused by wear or by thermal expansion due to temperature differentials may also have destructive effects which can be alleviated by using a dryer fabric having a lower modulus of elasticity.
The stress problem can be overcome in those cases where it is possible to disconnect the upper gear train from the lower gear train so that either the upper or the lower cylinders only are driven. In such cases the cylinders which are disconnected are rotated by the dryer fabric and it doesn't matter if they rotate at a different speed. There are some installations, however, in which it is not possible to disconnect some of the drive gears and it is in these cases where a fabric having low modulus of elasticity will be used to advantage.
A further disadvantage of the single fabric dryer system arises because of the relative thickness of a conventional fabric. For example, when the wet web of paper passes from an upper dryer cylinder where it lies under the fabric, to a lower dryer cylinder where it lies over the fabric, it is stretched due to the difference in diameters. This stretch, or paper draw, is proportional to the thickness of the fabric. Since it is easily extensible the wet web of paper will accommodate to the draw. However, as it progresses from a lower dryer cylinder to an upper dryer cylinder a negative draw is created and because the wet web of paper is non-elastic it separates from the fabric and billows out so that it can fold or overlap on itself before passing under the fabric at the upper dryer cylinder, thus nullifying the effect of the support of the fabric. It will be apparent therefore that it is advantageous to use the thinnest possible dryer fabric in the single fabric system.
SUMMARY OF INVENTION
The present invention provides a dryer fabric, for use on a papermaking machine, having reduced permeability and reduced modulus of elasticity. Said dryer fabric comprises a plurality of interwoven monofilament plastic polymeric warp and weft strands wherein at least the warp strands, which extend in the machine direction, have a flattened cross-section the long axis of which lies parallel to the plane of the fabric. The fabric of this invention has the advantages of being easy to clean and being non-absorptive.
An important feature of the flattened warp is that it has a near rectangular cross-section which has a lower resistance to bending about its long axis than a circular cross-section of the same area and therefore, for the same strength of loom blow during weaving, the spacing of the weft strands can be reduced greatly compared with the spacing when woven with circular warp. Also, because of the lower profile of the flattened warp, the diagonal apertures in the mesh which allow the passage of air are thereby reduced in size.
A further feature of the flattened warp is that with the long axis of the rectangular cross section being parallel to the weft yarns, the fabric is made more resistant to distortion in its own plane while permitting easy flexing of the fabric about the axis which is parallel to the weft strands, thus, making it easier for the fabric to flex around dryer cylinders and smaller diameter rolls in the dryer system.
Although reduced permeability is essentially attained by using flattened warp, further reduction in permeability, also a feature of the invention, may be attained by the use of monofilament weft strands that are shaped in cross-section so as to substantially conform to the horizontally directed intersticial weft direction passages of the mesh naturally formed by the woven warp strands to thereby reduce the space between adjacent weft strands.
The invention also features the use of round or shaped weft which is relatively malleable as compared to the warp so that during the weaving process, and subsequently under any stressful condition, it will tend to adapt itself to the shape of mesh interstices to thereby restrict them and reduce permeability further still.
A further feature of the invention is the use of round or shaped polymeric weft, that is hollow (tubular) so that it may more easily adapt itself to conform to the shape of the mesh interstices.
An important advantage of the flattened monofilament warp, either with round or with shaped monofilament weft, is that it provides low permeability in an all-monofilament dryer fabric without the necessity of adding bulked yarns, as described in Canadian Pat. No. 861,275, which absorb dirt and moisture, or adding bulky weft yarns comprising fine staple fibres which are low in bending resistance and contribute to reduced resistance of the fabric to distortion in its own plane.
Another advantage obtained in using flattened warp strands is that the points of contact, or cross-overs, between warp and weft (contact area between weft and warp) are increased which serves to help stiffen the fabric against distortion in its own plane.
A still further advantage of the flattened warp according to this invention is that the fabric from which it is woven is relatively thin and has been found to have an elastic modulus that is only about one half that of similar fabric woven of conventional round warp. As explained above, low thickness caliper and low modulus of elasticity is particularly advantageous if the fabric is to be used in a single fabric dryer system.
According to the above features, from a broad aspect, the present invention provides a dryer fabric for use in a paper making machine comprising a plurality of interwoven warp and weft monofilament plastic polymeric strands woven with approximately 100% warp fill. At least the warp strands, which extend in the machine direction, have a flattened cross-section with the long axis of the cross-section extending parallel to the plane of the fabric. The lowered profile of the flattened strands define restricted diagonal apertures in the mesh of the fabric to thereby reduce the permeability of the fabric uniformly throughout.
The weft strands, which extend in the cross-machine direction, may have either a round cross-section or a cross-section shaped to substantially conform to weft passages of the mesh naturally formed by the warp strands to further reduce permeability. As a further embodiment of the invention some or all of the weft strands may be hollow plastic strands or strands formed of plastic material which is relatively malleable as compared to the material of the warp strands so that they can adapt to conform to the shape of mesh interstices to partially fill these and still further reduce permeability of the fabric.
The fabric of this invention having the lowest permeability will have, besides flattened warp, weft strands shaped to substantially conform to weft passages of the mesh and weft strands that are relatively malleable as compared to the warp strands.
BRIEF DESCRIPTION OF DRAWINGS
A preferred embodiment of the present invention will now be described with reference to the examples illustrated by the accompanying drawings in which:
FIG. 1 is a schematic view of a typical dryer section as used in a papermaking machine;
FIG. 2 is a schematic view of a typical single fabric dryer section;
FIG. 3 is an enlarged sectional view of a portion of a dryer fabric illustrating interwoven weft and warp monofilament circular strands as presently utilized:
FIGS. 3A and 3B are cross-sectional views along section lines A--A and B--B of FIG. 3;
FIG. 4 is an enlarged sectional view of a fabric structure similar to that as shown in FIG. 3 but utilizing the flattened cross-section warp strands forming the improved dryer fabric of the present invention;
FIGS. 4A and 4B are sectional views along cross-section lines A--A and B--B of FIG. 4;
FIG. 5 is an enlarged sectional view of an all monofilament 4-shaft 8 repeat duplex weave dryer fabric of the prior art;
FIGS. 5A and 5B are sectional views along section lines A--A and B--B of FIG. 5;
FIG. 6 is an enlarged sectional view of a dryer fabric as shown in FIG. 5 but utilizing the flattened warp strands to obtain the improved dryer fabric of the present invention;
FIGS. 6A and 6B are sectional views along section lines A--A and B--B of FIG. 6;
FIG. 7 is an enlarged cross-section view of the flattened monofilament warp strand as utilized in the dryer fabric of the present invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to FIG. 1 there is schematically illustrated a sub-section of a typical dryer section in a papermaking machine (not shown). The top tier dryer cylinders are generally indicated at 10 and the bottom tier at 11. The paper web 13 passes in a serpentine fashion over the top and bottom dryer cylinders as shown. An endless top fabric 14 holds the paper web 13 tightly against the upper cylinders 10 as it passes partially around the first upper cylinder around a felt roll 15, partially around the remaining top cylinders 10 and around the other intervening felt rolls 15 then around return roll 16, passing over guide and tensioning rolls 24 and 23, respectively and over a steam heated dryer roll 17 to remove some of the residual moisture in the fabric and then over other return rolls 16, before it passes again over the first dryer cylinder to complete the cycle. Similarly an endless bottom fabric 18 holds the paper web 13 tightly against the lower dryer cylinders 11 as it passes around these and the intervening bottom felt rolls 19, return rolls 21, tensioning roll 25, guide roll 26, bottom fabric dryer roll 22 and other return rolls 21, substantially as shown. The areas, bounded by the paper web 13 both approaching and leaving a dryer cylinder and the dryer fabric as it leaves the previous cylinder, wraps a felt roll and approaches the next dryer cylinder, are called pockets 12. It is in these pockets 12 that a large quantity of the moisture is evaporated from the heated web of paper. Proper ventilation of the pockets 12 provides for removal of the moisture from the system and maintains the equilibrium of the evaporation process.
FIG. 2 represents, schematically, a typical dryer section in which all the cylinders are substantially the same diameter and are driven at the same number of revolutions per minute by interconnected gearing. As in FIG. 1, the upper tier dryer cylinders are generally indicated at 10 and the lower tier at 11. A single endless fabric, 14, passes in serpentine fashion around the first upper cylinder, down around the first lower cylinder, up around the second upper cylinder, down around the second lower cylinder and so on, then it passes around a return roll 16, a guide roll 24, a tensioning roll 23, a steam heated dryer roll 17 and other return rolls 16, as shown. The paper web 13 is introduced under the fabric at the first upper cylinder and follows the fabric, passing between it and the upper cylinders and outside the fabric at the lower tier cylinders. It will be seen that in respect to the fabric, because of the thickness of the paper web, the effective diameter at the upper cylinders is now larger than the diameter at the lower cylinders by an amount equal to twice the thickness of the paper web.
FIG. 3 shows generally at 30, a plain weave synthetic fabric structure of the prior art in which numeral 31 denotes consecutive warp strands and numeral 32 denotes consecutive weft strands. In this structure each warp strand 31 passes over a first weft strand 32, under the second weft strand, over the third and so on. Similarly, the adjacent warp strand passes under the first weft strand, over the second, under the third and so on. S 1 denotes the center-to-center distance between adjacent weft strands 32. In FIG. 3B "x" denotes the shortest distance between adjacent warp strands 31 in the vertical section taken at the point of tangency between warp and weft, thus representing the largest diagonal aperture which permits passage of air through the fabric 30.
Referring now to FIGS. 4, 4A and 4B there is shown the same fabric structure 30' made with warp monofilament strands 31' that have been flattened to the extent that its short axis "b" (see FIG. 7) is only about half (1/2) the diameter of round warp 31 of corresponding cross-sectional area.
In comparing the fabrics of FIGS. 3 and 4, it will be apparent that, due to the lower resistance to bending of the rectangular cross-section, the flattened warp 31' assumes a crimp more easily so that the center-to-center distance between weft strands, S 2 of FIG. 4, is smaller than S 1 of FIG. 3. Also, because of the flat profile of the flattened warp the distance "y" in FIG. 4B is noticeably less than the corresponding distance "x" in FIG. 3B. Similarly, because of the reduced spacing of weft strands 32', distance S 2 , the area of the roughly triangular interstice based on "y" in FIG. 4B is much smaller than that based on "x" in FIG. 3B.
FIGS. 5, 5A and 5B depict an all monofilament 4-shaft 8 repeat duplex weave dryer fabric 40, a type which is commonly used in the papermaking industry. In FIG. 5, numerals 41, 42, 43 and 44 are consecutive warp strands. The weft is paired in two layers and numbered 48 to 57 as shown. In this structure a warp strand 41 passes in order over a first pair of weft strands 50-51, between the second pair 52-53, under the third pair 54-55, between the fourth pair 56-57 and so on. The next consecutive warp strand passes between the first pair of weft strands, over the second pair, between the third pair and under the fourth pair. Similarly, the third and fourth consecutive warp strands are woven commencing under and between the first pair of weft strands respectively.
S 3 denotes the center-to-center distance between pairs of weft strands, 52,53 and 54,55 and "x" (see FIG. 5B) is again the shortest distance between adjacent warp strands in the vertical section taken at the point of tangency between warp and weft. Referring to FIG. 5A, P denotes the shortest distance between crossing pairs of warp strands taken in a vertical plane midway between pairs of weft strands.
Typically the conventional fabrics of FIG. 5, in the mesh ranges commonly used, yield air permeabilities in the range between 400 and 900 cu.ft./min./sq.ft. In order to reduce permeability in this type of construction as indicated above, it is common to add bulky yarns between some of the monofilament weft strands as shown at 58 in this figure. Bulky yarns are normally made from staple fibres which fluff out and fill the space between the wefts.
FIGS. 6, 6A and 6B show the same fabric 40' as illustrated in FIG. 5 but with the warp strands 41'-44' flattened as in FIG. 4. It will again be apparent that the distances S 4 and "y" in FIGS. 6 and 6B are less than the corresponding distances S 3 and "x" in FIGS. 5 and 5B. The distance "q" in FIG. 6A is not appreciably different from the corresponding distance "p" in FIG. 5A, but again due to the reduced spacing S 4 the area of the interstice bounding "q" is much less than the area of the interstice bounding "p".
As also shown in FIG. 6, we provide, as an alternative to bulky staple fibre yarns, extra monofilament strands 59 woven into the fabric. As further illustrated in FIG. 6, the extra strands may have a diamond or rectangular shaped cross-section, shown at 60, to further fill the passages 61 of the fabric without making the fabric susceptible to picking up more foreign substances or retaining more water. Although not shown, when three or more layers of weft strands 50, 51 are provided, two or more passages 61 will be formed in the area between adjacent pairs of weft strands, i.e. in the area delineated across the fabric between the distance S 4 , some or all of these passages may be filled with the shaped weft of the invention.
Further, all the weft strands may be made of plastic polymeric material that is more malleable whereby under stress in the wearing or other treatment of the fabric, the weft strands will deform to further fill the interstices of the mesh to still further reduce the permeability of the fabric.
In the case of each of these types of fabric the reduction in the dimensions S 2 and S 4 and "X" to "Y" results in a reduction insize of the interstices of the fabric and, therefore, a reduction in permeability. By the use of suitably flattened monofilament warp strands and with suitably shaped and possibly either hollow or more malleable weft strands the permeability of the fabric can be reduced to the 50 to 250 cu.ft./min./sq.ft. range without resorting to the use of fluffy bulked "stuffer" yarns with their attendant disadvantages.
Typical conventional monofilament dryer fabric, as shown in FIG. 5, has a thickness usually greater than 0.070 inches and an elastic modulus greater than 5000 lbs. per inch. Experimental fabric woven according to the invention as shown in FIG. 6, having warp strands flattened in the ratio of 2:1 and heat set in the normal way had an average thickness of 0.058 inches and an average modulus of elasticity of 2690 lbs. per inch. In general, fabric woven according to the invention will have a thickness within the range 0.035 to 0.070 inches and modulus of elasticity from 1500 to 3000 lbs. per inch.
The warp yarns and the shaped weft yarns of the present invention may be made by mechanical rolling apparatus for rolling round monofilament strands in the range of 0.2 mm to 1.0 mm in diameter between pairs of rolls in order to flatten them or similarly flat or shaped strands may be extruded from a specially shaped die or made by the use of slit film to produce ribbons of monofilament-like material. The flattened cross-sectional shape of a monofilament strand is shown at FIG. 7, in which "a" is the width and "b" the thickness. A possible cross-sectional area range of a flattened monofilament warp strand would be from 0.07 sq. mm. to 0.5 sq. mm. and a possible ratio range of a:b would be 1.1:1 to 3:1.
The fabric of the present invention would have a warp count preferably in the range of 30 to 100 strands per inch and a weft count preferably in the range of 10 to 100 strands per inch. | An improved dryer fabric, woven entirely from monofilament plastic polymeric warp and weft strands, having a lower permeability to air flow and lower modulus of elasticity than normal fabrics, wherein at least the warp strands are flattened in cross-section, with the long axis of the flattened section extending parallel to the plane of the fabric and wherein the weft strands may be shaped so as to more or less conform to the horizontally directed passages of the mesh naturally formed by the woven warp strands and may also be relatively more malleable than the warp strands so that under stress they can adapt to conform to the shape of mesh interstices thereby to restrict these and still further reduce the permeability. | 3 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a button sewing machine, and more particularly to a machine adapted for stitching buttons on the sleeves of a suit in series.
2. Description of the Prior Art
The known automatic button sewing machine is provided with a working table and cloth back-up plate movably placed on the table. A cloth such as a sleeve of a suit is placed on the cloth back-up plate. The machine is additionally y provided with a button holder vertically movable with respect to the cloth back-up plate. The accompanying drawings show the embodiments of the present invention but for explanatory convenience reference will be made to them. In FIG. 1 the reference numerals 1a, 4 and 5 denote the working table, the cloth back-up plate and the button holder, respectively.
Now, suppose that the machine is applied to sew decorative buttons on a sleeve of a suit. The sleeve is hung on the working table being backed up by the back-up plate as shown in FIG. 1, and the button holder is operated to sew buttons at desired positions on the sleeve wherein the button holder and the back-up plate are simultaneously moved about so as to locate the buttons at the desired positions.
The known automatic button sewing machines of such type are adapted for stitching buttons on the sleeves one by one. However if two or more buttons are to be attached in series a manual work is involved in shifting the sleeve portion from button to button. The necessity for manually shifting the sleeve negates the merit of the automated button sewing performance. Another disadvantage is the difficulty of visually locating buttons exactly at desired positions. A misalignment often occurs.
OBJECTS AND SUMMARY OF THE INVENTION
The present invention is directed to solve the problems pointed out with respect to the known button sewing machines, and has for its object to provide an automatic button sewing machine which can locate a plurality of buttons exactly in series.
Another object of the present invention is to provide an automatic button sewing machine which enables an inexperienced operator to stitch buttons on clothes easily.
A further object of the present invention is to provide an automatic button sewing machine which sews buttons on clothes quickly.
Other objects and advantages of the present invention will become more apparent from the following detailed description, when taken in conjunction with the accompanying drawings which show, for the purpose of illustration only, one embodiment in accordance with the present invention.
According to the present invention there is provided a button sewing machine for stitching buttons in series on an object material such as sleeves of suits, which machine includes a working table for holding the object material and a cloth back-up plate movably placed on the working table serving to back-up the object material during button sewing operations. A button holder is provided for picking a button from a button carrier and placing it at a desired position on the object material. A cloth holding and shifting arm is provided for pressing and shifting the object material laced on the table along the surface of the working table. A first driving unit is provided for effecting the ascent and descent of the cloth holding and shifting arm with respect to the working table. An interlocking unit is provided for effecting unitary movement of the cloth back-up plate, the button holder and the cloth holding and shifting arm, to thereby facilitate placement of the button held by the button holder at an appropriate position on the working table. A further driving unit is proved for shifting the cloth holding and shifting arm in the button aligning direction while it presses the cloth against the back-up plate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view showing a button sewing machine embodying the present invention;
FIG. 2 is a front view showing the machine of FIG. 1 which is ready to receive the cloth;
FIG. 3 is a schematic view showing the movement of a holding and shifting arm included in the machine; and
FIG. 4 is a cross-sectional view taken along the IV--IV line in FIG. 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The button sewing machine of the present invention, being generally denoted by the reference numeral 1, includes a working table 1a extending at one side from the machine body so as to allow an object material such as a sleeve of a suit to hang on. Hereinafter the object material will be referred to the cloth (T). There is provided a cloth back-up plate 4 slidable on the table la, which plate 4 is to back up the cloth (T) as shown in FIG. 1. The reference numeral 5 denotes a button holder. The cloth back-up plate 4 is movable horizontally with respect to the table 1a, and the button holder 5 is movable not only horizontally but also vertically.
Referring to FIG. 2, the button holder 5 is caused to descend and picks up a button 3 on a carrier 6, wherein the buttons are supplied onto the carrier one by one by a button feeder (not shown). The button holder 5 is provided with a pair of pinching arms 5a whereby the button is securely caught. After the button 3 is picked up the carrier 8 is withdrawn toward the button feeder. The button holder 5 carrying the button 3 is caused to descend and place it at the desired position on the cloth (T).
The reference numeral 9 denotes a cloth holding and shifting arm whereby the cloth (T) is shifted in the direction of the arrow on the table 1a. The cloth holding arm 9 is driven by a feed drive unit 10. As shown in FIG. 3 the arm 9 is U-shaped in which the button holder 5 is situated. Preferably the arm 9 is provided with small projections on its undersurface 9a (i.e. the cloth pressing surface) so as to prevent the arm 9 from slipping on the cloth (T).
The feed drive unit 10 includes an arm feeder 11 reciprocally moving so as to enable the arm 9 to move in a direction in which buttons are aligned, and simultaneously an arm lifter 12 is caused to ascend and descend through the operation of the arm feeder 11.
The arm feeder 11 includes a swinging arm 14 connected to the body of the button holder 5 by means of a pivot 13, a shaft 18 having a journal 15 at which the shaft 18 is pivotally connected to the swinging arm 14, a pneumatic cylinder 17 having a piston 18 secured to the shaft 18, the cylinder 17 being reciprocally moved along the shaft 18, and an arm supporting member 19 secured to the undersurface of the pneumatic cylinder 17, the member 19 supporting the cloth holding and shifting arm 9.
As shown in FIG. 3, the cylinder 17 includes a chamber dividable by a piston 18 into a left-hand section and a right-hand section. When the pressure is increased in the left-hand section the pneumatic cylinder 17 moves in the left-hand direction, thereby enabling the cloth holding and shifting arm 9 to push the cloth (T) over a predetermined distance. Then a pressure is increased in the right-hand section, the cylinder 17 returns to its original position. The reference numeral 20 denotes a control valve for adjusting the pneumatic pressure in the cylinder 17.
The arm lifter 12 comprises a pneumatic cylinder 12a, whose top end is pivotally connected to a coupling 22a, and whose piston 12b is pivotally connected to the opposite coupling 22b carried on the shaft 16. The coupling connection enables the arm lifter 12 to follow the maneuvering of the button holder 5 vertically and horizontally with respect to the cloth (T) placed on the table 1a. Another function of the arm lifter 12 is to vertically swing the arm feeder 11 around the pivot 13. Under the cooperation of the arm lifter 12 and the feed drive unit 10 the cloth holding and shifting arm 9 alternatively takes (1) the position of pressing the cloth (T) as shown in FIG. 1. and (2) the position of waiting for a subsequent operation in its raised posture as shown in FIG. 2.
A distance over which the cloth (T) is shifted is controlled through a sensor unit 23, which includes a reference shaft 24 secured to the body of the machine 1, and a photocell 26 secured to the pneumatic cylinder 17, the photocell 26 being adapted to read one of index members 25 during the movement thereof. In response to the detection of one index member 25 the control valve 20 stops the supply of pressurized air so that the pneumatic cylinder 17 is stopped at a desired position.
In sewing buttons 3 on the cloth (T) the button holder 5 and the cloth back-up plate 4 are caused to maneuver so as to locate the button 3 at a predetermined button position 3a. The arm 9 follows the maneuver of the button holder 5 while pressing the cloth (T). The unitary movement of the holder 5 and the arm 9 is ensured by an interlocking unit 28 shown in FIG. 4.
Referring to FIG. 4 the interlocking unit 28 will be described:
The interlocking unit 28 includes a groove 29 cut in the undersurface of the arm supporting member 19, and an engaging member 30 adapted to fit in the groove 29. When the arm 19 is in its waiting posture as shown in FIG. 2 the engaging member 30 is disconnected from the groove 29, and when the arm 19 comes into contact with the cloth (T), the groove 29 comes into engagement with the engaging member 30.
The buttons will be sewn on the cloth (T) with stitches in the following manner:
Suppose that the cloth (T) be a sleeve 2. The index members 25 are positioned in accordance with the number and distance between one button and another. In the illustrated embodiment three index members 25 are provided on the reference shaft 24.
The sleeve 2 is hung on the plate 1a, and backed up by the back-up plate 4. Then the cuff of the sleeve 2 is positioned at a starting position on the table 1a so that the remotest button position from the cuff is the first stitch. The starting position is previously determined in accordance with the number of buttons and a desired distance between one button and another.
After the button positions are set the arm lifter 12 is operated to cause the arm 9 to descend and press the sleeve 2 against the cloth back-up plate 4. At this stage the machine 1 is switched on. A button 3 is supplied to the button carrier 6 by means of a button feeder (not shown). and the button holder 5 picks up the button 3 to place it at the prescribed position on the sleeve 2. Then the button 3 is stitched there. In placing the button at the desired position the arm 9 maneuvers in association with the button holder 5 under the action of the interlocking unit 28 while it presses the sleeve 2 against the back-up plate 4. More specifically the arm 9, the button holder 5 and the cloth back-up plate 4 move together.
When a predetermined number of stitches (normally, nine to thirty-six stitches) are given the machine 1 is stopped, and the pinching arms 5a of the button holder 5 are opened to release the button 3 sewn to the sleeve 2. Then the button holder 5 is caused to rise above the sleeve 2.
The control valve 20 is turned on to cause the cylinder 17 to travel over a predetermined distance along the shaft 18, thereby enabling the arm 9 to push the sleeve 2 on the back-up plate 4. In this way the sleeve 2 is shifted to the left (in FIG. 1) by a distance which corresponds to the distance between one button and the next. This shifting distance is previously determined, and maintained by the sensor unit 23.
The next button 3 is supplied onto the carrier 6, and subsequently the same procedure as mentioned above follows. In this way three buttons are sewn one by one by repetition of the same procedures. After the sewing work is finished the arm is raised by the arm lifter 12, and the pneumatic cylinder 17 is returned to the original starting position.
The number of buttons to be sewn, the distance between one button and the next, and the starting position can be changed as desired by changing the positions of the index members 25.
In the embodiment described above the pneumatic cylinder 17 is operated every time when one button is stitched. This repetition of movement continues until the predetermined number of buttons are sewn. However the distances between the buttons are normally the same. Taking advantage of this fact it is possible to arrange that the pneumatic cylinder 17 is caused to move forward by the same distance every time when one button is sewn, and during the repetition the cloth (T) is shifted by an inter-button distance until the predetermined number of buttons are sewn.
Instead of employing the pneumatic cylinder 17 a pulse motor can be used to operate the arm feeder 11.
In the illustrated embodiment the cloth holding and shifting arm 9 is U-shaped as shown in FIG. 3, but instead of providing a single U-shaped arm it is possible to provide two parallel arms secured to the arm supporting member 19.
The arm lifter 12 can be operated by he known means other than the pneumatic cylinder, so that the cloth holding and shifting arm 9 can alternatively take the cloth pressing posture and the waiting posture away from the cloth.
In the foregoing description the cloth (T) is a sleeve of a suit but the present invention is applicable to the button sewing on any other fabric material. According to the present invention buttons can be sewn not only lengthwise of the machine but also crosswise thereof. To effect the crosswise sewing of buttons it has only to modify so that the cloth holding and shifting arm 9 can move crosswise of the machine. | An automatic button sewing machine for stitching buttons in series on a fabric includes a working table for supporting the fabric and a back-up plate movably disposed on the working table to back-up the fabric during button sewing operations. A button holder is provided for picking up a button and placing it at a desired position on the fabric. A cloth holding and shifting arm is provided for shifting the fabric from one button to the next. The cloth back-up plate, the button holder and the cloth holding and shifting arm are moved together, thereby placing the buttons at appropriate positions on the fabric during button sewing operations. | 3 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
Perhaps one of the most disagreeable tasks in the home is the periodic cleaning of toilet bowls in bathrooms. Conventional cleaning of toilet bowls is generally manually accomplished by means of hand-held brushes of various shapes, using cleaners or disinfectants. This cleaning is absolutely essential in the home for sanitary reasons, and considerable effort is necessary with a hand brush and detergent to completely and thoroughly clean the bowl. The utility brush of this invention is designed to quickly, efficiently and automatically clean toilet bowls without the necessity of using hand-held brushes. In addition to household use, the utility brush can be used in hotels, office buildings, plants and industry, schools, and in institutions, such as hospitals and nursing homes, and in all applications by janitorial and maid services.
2. Description of the Prior Art
No known automatic devices are available on the market or in the art to effect automatic cleaning of toilet bowls, although U.S. Pat. No. 3,599,246 to Angelo Bramati, et al, discloses a water closet seat cleaning device which utilizes a chain arranged in a closed loop and a sweeper means secured to the chain to clean toilet seats.
Accordingly, it is an object of this invention to provide a new and improved automatic device for cleaning toilet bowls, which device includes a motor-driven, shaped brush removably bracketed to the rim of a toilet bowl, with the brush extending into the bowl to rotatably clean the interior of the bowl.
Another object of this invention is to provide a new and improved, automatic toilet bowl brush which includes a housing containing a motor and having a tapered and shaped brush rotatably mounted to the motor shaft, which housing and brush can be removably bracketed to the rim of a toilet bowl of substantially any size and shape, with the brush extending inside the bowl to automatically clean the bowl.
Yet another object of this invention is to provide a new and improved rotatable brush mechanism or machine for cleaning toilet bowls which includes an electric motor enclosed within a motor housing, which motor is mounted in cooperation with a brush having a "stepped" or cone-shaped configuration to match the interior configuration of the toilet bowls, the housing being designed to removably mount on the rim of the bowls to effect quick, efficient rotatable cleaning of the interior of the toilet bowls.
A still further object of the invention is to provide a new and improved, rotatable, brush-mounted toilet bowl cleaner which includes a generally cylindrically-shaped housing having a motor mounted in the interior thereof and carrying a rotatable shaft and a brush extending downwardly of said housing and attached to the shaft, which housing is capable of being removably mounted on a toilet bowl with the brush projecting inside the bowl to rotatably clean the bowl upon activation of the motor.
Another object of the invention is to provide an automatic brush mechanism for cleaning toilet bowls, which brush mechanism is characterized by a housing, a motor and a cooperating timer for controlling trhe time of operation, the speed and/or the direction of rotation of a shaft and brush to clean the bowls.
SUMMARY OF THE INVENTION
These and other objects of the invention are provided in a new and improved utility brush which, in a preferred embodiment, is characterized by a generally cylindrically-shaped housing of high structural integrity carrying a motor and a cooperating timer, and a shaft projecting downwardly from the motor, to which shaft is removably attached a brush having a configuration generally in the shape of the interior of a toilet bowl. A bracket mounted to the housing is included for removably mounting the utility brush on the rim of a toilet bowl and projecting the brush into the bowl to effect rotatable cleaning of the bowl upon activation of the motor and timer.
BRIEF DESCRIPTION OF THE DRAWING
The invention will be better understood by reference to the accompanying drawings, wherein:
FIG. 1 is a perspective view, partially in section, of a preferred embodiment of the utility brush of this invention;
FIG. 2 is a sectional view taken along lines 2--2 of the utility brush illustrated in FIG. 1, more particularly illustrating the brush mounted in functional position on the rim of a toilet bowl;
FIG. 3 is a perspective view of the utility brush illustrated in FIGS. 1 and 2 with a mounting bracket attached;
FIG. 4 is an exploded view of a preferred embodiment of the utility brush illustrated in FIGS. 1-3; and
FIG. 5 is a sectional view, taken along lines 6--6 in FIG. 4, of a preferred brush shaft coupling for removably mounting the brush shaft to the main shaft.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1 of the drawings, in a preferred embodiment of the invention the utility brush of this invention is generally illustrated by reference numeral 1, and includes a housing 2, characterized by a first housing segment 3 and a second housing segment 4 in mating relationship. First housing segment 3 and second housing segment 4 are removably joined by a plurality of flange screws 9, and are closed at the top by a housing top 34, which serves to support an electric cord 56, with a plug 57, emerging from housing top aperture 35. A switch 61 serves to initiate and terminate the flow of electric current through electric cord 56 and plug 57. A brush generally illustrated by reference numeral 45 is generally configured to fit the interior of a toilet bowl by the shaping of bristles 47 into a top bristle cluster 48; a middle bristle cluster 49; a lower bristle cluster 50; and a bottom bristle cluster 51, as illustrated. The multiple bristles 47 are carried by a common brush shaft 46, which extends beneath housing 2 of utility brush 1.
Referring now to FIGS. 2 and 3 of the drawings, in a preferred embodiment of the invention a mount bracket 38 is secured to housing 2 by means of a mount bracket collar 39, and a collar set screw 40, which can be adjusted to position mount bracket 38 in a 360° arc on housing 2, as desired. Mount bracket 38 is further provided with downwardly extending exterior flanges 60, each carrying a mount bracket pad 41 for engagement with the toilet bowl rim 43 of toilet bowl 42, at toilet bowl rim neck 44, as illustrated in FIG. 2. The projection of brush 45 into toilet bowl 42 is illustrated in FIG. 2, with top bristle cluster 48 in close proximity to the top interior surface of toilet bowl 42 to insure thorough and complete cleaning of inside of the bowl rim.
Referring now to FIGS. 2, 4 and 5, in a preferred embodiment of the invention first housing segment 3 and second housing segment 4 are each shaped to provide a first housing segment flange 6 on first housing segment 3, and a second housing segment flange 10 on second housing segment 4. First housing segment flange 6 defines a first housing segment seat 7, while second housing segment flange 10 shapes a second housing segment seat 11, as illustrated. On the opposite edges of first housing segment 3 and second housing segment 4, respectively, are provided a first housing segment edge 8 on first housing segment 3, and a second housing segment edge 12, on second housing segment 4. Accordingly, when first housing segment 3 is joined to second housing segment 4 as illustrated in FIGS. 1, 2 and 3, first housing segment flange 6 fits against second housing segment edge 12 as second housing segment edge 12 registers with first housing segment seat 7. Furthermore, second housing segment flange 10 matches with first housing segment edge 8 as first housing segment edge 8 registers with second housing segment seat 11. Housing top 34 is designed to register with segment slots 5 provided in the top of first housing segment 3 and second housing segment 4, while housing bottom 36, provided with housing bottom aperture 37, fits in registration with the segment slots 5 provided at the bottom of first housing segment 3 and second housing segment 4, respectively. First housing segment 3 and second housing segment 4 are then joined by flange screws 9 which, in a preferred embodiment, are threaded, and cooperate with matching threaded edge apertures 16, provided in first housing segment edge 8 and second housing segment edge 12, and top flange apertures 17 in first housing segment flange 6 and second housing segment flange 10. A motor 28 is provided inside housing 2 with motor shaft 30 maintained in registration with a shaft 31 and a brush shaft 46 by means of a top motor bracket 20, a lower motor bracket 23, an upper shaft bracket 25 and a lower shaft bracket 26. Lower motor bracket 23 is fitted with a motor shaft aperture 24 to accommodate shaft 31, and motor 28 is mounted to top motor bracket 20 and to lower motor bracket 23 by means of motor bolts 29, which extend through motor bolt apertures 21, and cooperating nuts 59. Shaft 31 is removably attached to motor shaft 30 of motor 28 by a motor shaft coupling 32, which is provided with a pair of set screws 33, as illustrated. Furthermore, shaft 31 is maintained in axial alignment inside housing 2 by means of a pair of shaft bushings 27, provided in both upper shaft bracket 25 and lower shaft bracket 26, respectively. Top motor bracket 20, lower motor bracket 23, upper shaft bracket 25 and lower shaft bracket 26 are anchored to first housing segment 3 and second housing segment 4 of housing 2 in off-set, staggered fashion by means of bracket screws 13, which project through holes or apertures in housing 2 and engage threads formed in bracket screw apertures 22. For example, top motor bracket 20 is secured to first housing segment 3 and second housing segment 4 by means of a pair of bracket screws 13 projecting through top housing apertures 14 and threadably engaging top motor bracket 20 through bracket screw apertures 22. Similarly, lower motor bracket 23 is removably affixed to first housing segment 3 and second housing segment 4 by means of a second pair of bracket screws 13 which project through middle flange apertures 18. Likewise, upper shaft bracket 25 is mounted to first housing segment 3 and second housing element 4 by means of a pair of bracket screws 13 which are inserted through middle housing apertures 15. Furthermore, lower shaft bracket 26 is mounted to first housing segment 3 and second housing segment 4 by means of a pair of bracket screws 13 which are fitted through bottom flange apertures 19 and engage bracket screw apertures 22.
Referring now specifically to FIG. 5 of the drawings, in a preferred embodiment of the invention brush shaft 46 is removably coupled to shaft 31 by means of a brush shaft coupling 52 which is provided with an internal shaft bore 53 large enough to accommodate sahft 31, and a brush shaft bore 54 which is smaller than shaft bore 53 and yet is sufficiently large to accommodate the somewhat smaller brush shaft 46. In this manner brush shaft 46 can be securely, yet removably, coupled to a larger shaft 31 by tightening or removing a pair of set screws 33 threadably cooperating with threaded set screw apertures 55 It will be appreciated that a "quick release" button or mechanism can be provided as deemed necessary to remove brush shaft 46 from shaft 31 and/or brush shaft coupling 52, according to the knowledge of those skilled in the art.
Referring again to FIGS. 2 and 4 of the drawings, an electric cord 56, having a conventional plug 57 extends through housing top aperture 35, and is wired to motor 28 through a switch 61 in conventional fashion. However, in a preferred embodiment of the invention the electric cord 56 is wired to motor 28 through a timer 58, which permits utility brush 1 to be operated in one or more timed sequences of selected duration, according to the degree of cleaning necessary. It will be appreciated that motor 28 may be of either fixed or variable speed and the motor speed may be controlled either manually through a multiple position switch 61, or automatically, with or without the use of a timer 58, according to the knowledge of those skilled in the art. Accordingly, timer 58 can be used simply to stop motor 28 after a preset cleaning cycle, or it can be utilized to activate one or more timed cleaning sequences, including clockwise and counter-clockwise rotation of motor 28.
In another preferred embodiment of the invention utility brush 1 is provided with a cover or shroud (not illustrated) which may be split or otherwise designed to fit over the toilet bowl 42 and brush 45 in order to permit brush 45 to rotate at relatively high speed for more intense and thorough cleaning. The cover permits high brush speeds without splashing water from toilet bowl 42.
It will be recognized that brush 45 can be quickly and easily removed from shaft 31 for drying, storage or replacement by simply loosening one of set screws 33 and sliding brush shaft 46 or shaft 31 from brush shaft coupling 52, or activating an alternative "quick-release" mechanism, as heretofore described. Furthermore, shaft 31 can be removed from motor shaft coupling 32 by loosening the lower one of set screws 33 and disengaging shaft 31, after first housing segment 3 and second housing segment 4 are removed. If it is desired to remove shaft 31 from motor shaft coupling 32 without removing first housing segment 3 and second housing segment 4, a hole can be provided in either first housing segment 3 or second housing segment 4 for insertion of a screwdriver or other tool to facilitate loosening of one of set screws 33.
In operation, utility brush 1 is assembled as illustrated in FIGS. 2-4 with mount bracket 38 in position on first housing segment 3 and second housing segment 4. Brush 45 is then placed inside toilet bowl 42 and flanges 60 of mount bracket 38 are fitted over toilet bowl rim 43, with mount bracket pads 41 in secure contact with bowl rim 43, as illustrated in FIG. 2. It will be appreciated that bracket 38 can be adjustable, if desired, to fit toilet bowl rims of varying size, according to the knowledge of those skilled in the art. A cleaning agent and/or disinfectant can then be added to the water in the bowl, and the plug 57 inserted in the wall outlet. Switch 61 may then be manipulated to the desired motor speed which is a matter of choice for one skilled in the art, or to the timer sequence position, and a cover may be used if relatively high rotational brush speeds are desired.
It will be further appreciated by those skilled in the art that housing 2 of utility brush 1 is, in a preferred embodiment formed of aluminum in order to provide a high degree of structural integrity and corrosion resistance with little weight. However, it will be understood that other materials such as fiberglass, plastic and the like may be used to construct housing 2, according to the knowledge of those skilled in the art. Furthermore, in yet another preferred embodiment, brush 45 is designed in a generally cone-shaped configuration, with bristles 47 of substantially medium stiffness and of varying length in the top bristle cluster 48, middle bristle cluster 49, lower bristle cluster 50 and bottom bristle cluster 51, in order to facilitate folding of the longest bristles 47 in each respective cluster and contact of the shorter bristles 47 in the clusters with the inside surfaces of a relatively small toilet bowl. | A utility brush for automatic cleaning of toilet bowls which includes a generally cylindrically-shaped housing containing a motor, and in a preferred embodiment, a timer, with a shaft coupled to the motor and extending through brackets in the housing to removably carry a tapered, generally cone-shaped brush projecting beneath the housing. The brush is "stepped" or shaped and configured to match the interior shape of toilet bowls for thorough cleaning, and the housing is provided with a mount bracket for removably securing the housing to the rim of the toilet bowls with the brush projecting downwardly inside the bowls. The brush is electrically operated and may be designed to rotatably clean the toilet bowls in multiple, timed sequences. | 8 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a National Stage of International patent application PCT/EP2013/073198, filed on Nov. 6, 2013, which claims priority to foreign French patent application No. FR 1203012, filed on Nov. 9, 2012, the disclosures of which are incorporated by reference in their entirety.
FIELD OF THE INVENTION
The field of the invention is that of a photodiode receiver which receives light pulses over a very wide dynamic range (from several nanoamperes to several tens of milliamperes). This dynamic range is provided by means of a device for gain switching by discrete values, called “pads”.
BACKGROUND
The most commonly used solution for producing such a receiver is that of providing a photodiode with a TIA (an acronym for the English expression “Transimpedance Amplifier”); the sensitivity performance is dependent on this TIA, which has a high gain bandwidth product (or “GBW”, an acronym for the English expression “Gain Bandwidth Product”) and very low noise.
A photodiode 1 is conventionally represented by the circuit shown in FIG. 1 a . As shown in the left-hand figure, this photodiode is preferably charged by a resistor R′ d between the anode and the ground so as to absorb the direct current due to the ambient illumination, also called the background current, which is included in the light signal received by the photodiode. According to the equivalent representation shown in the right-hand figure, this resistor R′ d in parallel with the internal resistance of the photodiode forms an equivalent resistor Rd. The photodiode is generally characterized by a capacitance Cd between the anode and the ground, shown in the right-hand figure.
In a conventional receiver circuit, an example of which is shown in FIG. 1 b , a photodiode 1 of this type is associated with a TIA 2 via a linking capacitor C liaison which helps to separate the useful pulses from the background current. The value of this linking capacitor C liaison is typically more than 10 nF. Let us recall that a TIA comprises, in parallel, an operational amplifier AOP or an amplifier with discrete components, a feedback resistor R f and a stabilizing capacitor C f . Such a receiver makes it possible to neutralize the effect of the parasitic capacitance C d of the photodiode by means of a virtual ground.
To a first approximation, this is a second-order loop system:
Having a conversion gain Z T (p) such that
Z
T
(
p
)
=
V
s
i
D
=
-
R
f
1
1
+
2
ζ
ω
n
p
+
p
2
ω
n
2
(
eq
1
)
where V s is the output voltage of the circuit, i D is the current generated by the photodiode, p (p=jω=j2πf) is the Laplace variable, R f is the feedback resistance of the TIA, and ξ is the damping of the receiver,
and having a natural frequency ω n such that:
ω
n
=
2
π
GBW
R
f
(
C
d
+
C
f
)
(
eq
2
)
The ratio of damping to natural frequency can be written thus:
ζ
ω
n
=
1
2
(
R
f
C
f
+
1
2
π
GBW
(
1
+
R
f
R
d
)
)
(
eq
3
)
or in practice:
R
f
C
f
>>
1
2
π
G
B
W
(
1
+
R
f
R
d
)
(
eq
4
)
this ratio then takes the simple form:
ζ
ω
n
≈
1
2
R
f
C
f
(
eq
5
)
The gain modification is found according to Equation (1) from the change in the value R f which, according to Equation (2), modifies the natural frequency ω n and hence the damping ξ according to Equation (5). With a conventional solution, therefore, it appears to be difficult to change the gain without modifying the transfer function.
The frequency response is shown in FIG. 5 a for three damping values ξ (0.9, 0.7 and 0.5). This figure demonstrates that the change in gain affects the damping when the band is kept constant.
Another important criterion is the equivalent current noise applied to the input of the TIA, which is written thus:
i n = i n - 2 + ( e n R f ) 2 + 4 kT R f ( eq 6 )
where i n− and e n , respectively, are the equivalent noise current at the negative input of the operational amplifier AOP and the equivalent noise voltage at the input of AOP which characterize the operational amplifier used, k is the Boltzmann constant, and T is the temperature in degrees Kelvin.
For a given TIA and a given photodiode, the sensitivity is optimized by choosing the highest possible resistance R f compatible with the pulse processing band.
However, as the gain increases, the admittance decreases, because the voltage range at the output of the amplifier is fixed by the power supplies. Conversely, a decrease in gain increases the admittance but degrades the noise, with a current limitation determined by the maximum output current of the amplifier.
The problem therefore arises of providing an optimum receiver for weak signals but also for strong signals, while preferably maintaining the same frequency response. The conventional solutions are:
Reducing the gain of the TIA by reducing the feedback resistor R f which determines the conversion gain of the TIA, thereby improving the admittance but worsening the noise. Furthermore, reducing the feedback resistance has the effect of significantly increasing the bandwidth, which is evidently undesirable if a pulse shape independent of gain is required. Placing a switched resistive attenuator between the photodiode and the TIA so as to reduce the gain when the received level exceeds the admittance. This degrades the noise, because the resistances generate noise. Moreover, the switches have non-negligible parasitic capacitance relative to the capacitance of the photodiode, which affects the transfer function.
The conventional solutions do not meet the requirement.
Consequently there is still a need for a receiver with a wide dynamic range, optimized in terms of noise.
SUMMARY OF THE INVENTION
More precisely, the invention proposes a receiver of a pulsed light signal comprising:
a photodiode adapted to generate an electric current I d in response to the light signal, having a parasitic capacitance C d as its characteristic, an electrical ground, and a transimpedance amplifier connected to the input of the photodiode by a linking capacitor C liaison .
It is primarily characterized in that it includes a series-parallel reactive circuit, consisting of a capacitor C p which, combined with the diode capacitance C d , forms a current divider, called an attenuation pad, upstream of the transimpedance amplifier.
This current divider enables the signal to be attenuated without degrading the noise.
The capacitor Cp is typically placed in series with the linking capacitor and generally supplements it.
According to one characteristic of the invention, the receiver includes a background current resistor R d located between the photodiode and the electrical ground, the capacitance C d and said resistor R d having an impedance Z d , and the attenuation pad also consists of a resistor R p in parallel with the capacitor C p , thus forming a parallel electrical network called an aperiodic attenuation pad, having an impedance Z p , where
Z p =(α−1) Z d .
This aperiodic attenuation pad can be used to compensate the effect of the resistor Rd and thereby maintain the low frequency response of the receiver.
If required, the attenuation pad further comprises a switch in parallel with the capacitor C p , so as to produce a switchable attenuation pad. This switch enables the circuit R p C p to be short-circuited or switched.
The attenuation pad may also include a capacitor C opt in parallel with C d , this capacitor C opt itself being switchable if required.
The aperiodic attenuation pad may also comprise a compensation capacitor C comp in parallel with the input of the transimpedance amplifier, thus forming a compensated aperiodic attenuation pad, with C comp =C d (α−1)/α, this compensation capacitor being switchable if required.
Given that the assembly consisting of the attenuation pad and the transimpedance amplifier is called a receiving channel with attenuation pad, the receiver further comprises a receiving channel without attenuation pad, comprising another transimpedance amplifier, these receiving channels being multiplexed by means of an input switch of these channels and an output switch of these channels, the switches being synchronized with one another so as to produce a receiver with different gains. Evidently, other receiving channels with attenuation pads may be multiplexed with said receiving channels, each receiving channel with an attenuation pad having a different attenuation.
The light signal is typically capable of generating current pulses in the range from 10 nA to 100 mA in the photodiode.
BRIEF DESCRIPTION OF THE DRAWINGS
Other characteristics and advantages of the invention will be revealed by the following detailed description, provided by way of non-limiting example, with reference to the attached drawings, in which:
FIG. 1 a , described above, shows two equivalent schematic representations of a photodiode having a background resistor;
FIG. 1 b shows schematically a receiver circuit according to the prior art, including a photodiode and a TIA;
FIG. 2 shows schematically an example of a receiver circuit according to a first embodiment of the invention with a purely capacitive attenuation pad;
FIG. 3 a shows schematically an example of a receiver circuit according to a second embodiment of the invention, with an aperiodic attenuation pad switched around Rp Cp;
FIG. 3 b shows schematically an example of a receiver circuit according to a third embodiment of the invention, with an aperiodic attenuation pad switched around Cd;
FIG. 3 c shows schematically an example of a receiver circuit according to a fourth embodiment of the invention, with a compensated aperiodic attenuation pad;
FIG. 4 shows schematically an example of a receiver circuit according to a fifth embodiment of the invention, with a plurality of switched receiving channels;
FIG. 5 a shows the frequency response of a conventional receiver with constant bandwidth for three values of gain, showing a variation in damping;
FIG. 5 b shows the frequency response of a receiver with a compensated aperiodic pad with a constant bandwidth for three values of gain, showing how the damping is maintained.
The same elements are identified by the same references in all the figures.
DETAILED DESCRIPTION
The receiver according to the invention is based on the principle of a current divider bridge which is capacitive instead of resistive.
An example of a capacitive attenuation pad associated with a photodiode 1 equipped with a TIA 2 is shown in FIG. 2 . In this figure, the aim is more particularly to indicate the electrical currents.
The photodiode is an ideal current generator, and is capacitive because of the parasitic capacitance Cd. When a capacitor Cp is added in series between the TIA 2 and the photodiode 1 , at the input or output of the linking capacitor, the current generated by the photodiode is distributed between the capacitance Cd and the capacitor Cp as a function of the values of the capacitances:
I F = I D α
via the capacitance C p ;
I Cd = α - 1 α I D
via the capacitance C d ;
The value of the capacitance
C p = C d α - 1
determines the attenuation
α = C d + C p C p
of the capacitive divider. The signal is therefore attenuated without the addition of supplementary noise.
We find that α>1; in practice, an attenuation α typically in the range from 2 to 30 is chosen. The value of C p is typically less than 10 pF.
This attenuation pad 30 consisting of the capacitor Cp is provided, if required, with a switch 31 placed in parallel with this capacitor Cp to adapt the gain to the received level.
Let us analyze in greater detail the behavior of such a receiver at low frequencies, that is to say below 100 kHz:
As indicated in the preamble, the photodiode 1 is generally charged by a resistor Rd so as to absorb the direct current due to the ambient illumination. This resistor Rd modifies the impedance of the photodiode, which can then no longer be considered as purely capacitive.
As shown in FIG. 3 a , the capacitor Cp is then supplemented with a resistor Rp in parallel, which forms, with this capacitor, a parallel electrical network called an aperiodic attenuation pad 30 having an impedance Zp, proportional to Zd which is the impedance of the diode circuit including the resistance R d and the capacitor C d in parallel.
Assuming that Zp=(α−1)Zd, we find:
{ I F = I D α R p = ( α - 1 ) R d C p = 1 ( α - 1 ) C d
I F being the output current of the attenuation pad 30 .
The attenuation of the current then becomes independent of frequency, the additional noise remaining very low because the resistor Rp is large relative to Rd, owing to the attenuation ratio α.
This aperiodic attenuation pad 30 is provided, if required, with a switch 31 placed in parallel with Rp and Cp.
Let us now analyze in greater detail the behavior of such a receiver at high frequencies, that is to say above 10 MHz:
With the previous receiver circuit, the TIA 2 no longer sees the same impedance when the attenuation pad is active, and its transfer function is affected by this, as shown in FIG. 5 a for curves of gain as a function of frequency for three values of damping ξ(0.9, 0.7 and 0.5). The circuit behaves as a second-order system.
The ratio of damping to natural frequency is:
ζ ^ ω ^ n = 1 2 · [ R f · C f + 1 2 · π · G B W · ( 1 + R f a · R d ) ]
When the condition of a sufficient product of gain×band is met:
R f · C f >> 1 2 π G B W ( 1 + R f a R d )
the ratio of damping to natural frequency remains constant:
ζ ^ ω ^ n = ζ ω n ≅ 1 2 R f C f
But:
The natural frequency {circumflex over (ω)} n corresponds to that of a circuit whose photodiode has a parasitic capacitance which is reduced by a ratio α:
ω
n
=
2
π
G
B
W
R
f
(
C
d
+
C
f
)
⇒
ω
^
n
=
2
π
G
B
W
R
f
(
C
d
α
+
C
f
)
The static gain Z T is divided by α, as desired:
Z
T
=
-
R
f
1
1
+
2
ζ
ω
n
p
+
p
2
ω
n
2
⇒
Z
^
T
=
-
R
f
α
×
1
1
+
2
ζ
^
ω
^
n
p
+
p
2
ω
^
n
2
Since an attenuation α is created, the natural frequency {circumflex over (ω)} n of the receiver also increases, but the damping increases because the ratio of damping to natural frequency remains constant.
To retain the same bandwidth with and without attenuation, the damping must be modified; compensation is therefore added to produce the same transfer function.
Since the ratio of damping to natural frequency is invariant, the damping and the natural frequency are maintained simultaneously by adding a compensation capacitor C comp 43 shown in FIG. 3 c , in parallel on the input of the TIA 2 , such that:
ω
n
=
ω
^
n
⇔
2
π
G
B
W
R
f
(
C
d
α
+
C
COMP
+
C
f
)
=
2
π
G
B
W
R
f
(
C
d
+
C
f
)
Therefore
:
C
comp
=
α
-
1
α
C
d
The aperiodic attenuation pad modified in this way is then called a “compensated aperiodic attenuation pad”.
Such a receiver exhibits the same transfer function regardless of whether or not the pad is active.
In addition to the switch 31 (the first switch), another switch 44 may be placed in series with the compensation capacitor C comp , between the latter and the ground. The compensated aperiodic attenuation pad 30 operates when this other switch 44 is closed and the first switch 31 is open, and vice versa.
In the definition of the aperiodic pad, the value of the capacitor C p is related to the capacitance C d of the detector and to the attenuation ratio. For a value of Cd in the range from 12 to 18 pF, we therefore find, according to the formula
Cp = 1 ( α - 1 ) Cd
and with α in the range from 10 to 20, a very low value of Cp in the range from 0.5 to 2 pF, which is difficult to control in an industrial context in the production of a circuit. The solution proposed in FIG. 3 b consists in artificially increasing the capacitance Cd by adding a capacitor C opt 41 in parallel, thereby enabling the value of Cp to be increased at an equal attenuation. This capacitor C opt can be switched by a switch 42 placed in series toward the ground.
In practice, switches are imperfect, and fitting them may introduce parasitic elements which, in some cases, may degrade the transfer function. The term “receiving channel with an attenuation pad 50 ” denotes the assembly consisting of the attenuation pad 30 and the transimpedance amplifier 2 . The attenuation pad may or may not be aperiodic, may or may not be switchable, may or may not be compensated, and so forth. A proposed alternative is to use a plurality of receiving channels, each having a different gain, as shown in FIG. 4 with two values of gain. In this example, the receiver has two receiving channels:
a receiving channel 50 with a pad, optimized with a compensated aperiodic attenuation pad, and a receiving channel 50 ′ without a pad (having only a transimpedance amplifier 2 ) optimized at maximum gain.
The channel is typically selected by means of a switch 61 located at the input of these channels and a switch 62 located at the output of these channels, these switches being synchronized with one another to produce a receiver with different gains. The input switch 61 is advantageously provided with a linking capacitor on each of its outputs leading to a receiving channel.
The receiver provided with an attenuation pad in this way has the following advantages:
Greater admittance than a conventional circuit; A frequency response independent of the gain; Optimized noise; Allowance for the parasitic capacitances of the switches; No need for a compromise between sensitivity and power behavior; Simplicity of production.
This receiver is typically integrated into a Lidar system. It may be used as an element of a distance gauge, notably a semi-active distance gauge, that is to say one equipped with a designation laser adapted to illuminate a target whose backscatter is measured by this receiver. The target emits, for example, light pulses at a constant level, but if the receiver is at a long distance it can only measure very low-level pulses, whereas it can measure high-level pulses when it is at a short distance. | A receiver of a pulsed light signal comprises a photodiode adapted to generate an electric current in response to this light signal, having a parasitic capacitance C d as its characteristic; an electrical ground; and a transimpedance amplifier connected to the input of the photodiode by a linking capacitor C liaison . It includes an attenuation pad located between the photodiode and the transimpedance amplifier, consisting of a capacitor C p where C p =C d /(α−1), α being a predetermined attenuation, where α>1. | 6 |
FIELD OF INVENTION
This invention relates to a bipolar transmission system and more particularly to apparatus for detecting the start of frame in such a system.
BACKGROUND OF THE INVENTION
As one can ascertain, there are numerous line codes that are specifically designed to not contain DC energy and thereby be unaffected by DC removal. One such example of such a line code is bipolar coding which solves the DC wander problem by using three levels to encode binary data. Specifically, a logic "0" is encoded with zero voltage while a logic "1" is alternately encoded with positive and negative voltages. Hence the average voltage level is maintained at zero to eliminate DC components in the signal spectrum. Since bipolar coding uses alternate polarity pulses for encoding logic "1's", it is also referred to as "alternate mark inversion" (AMI). Mark is a term arising from telegraphy to refer to the active or "1" state of a level encoded transmission line. Bipolar coding is the basic line coding procedure used in many telephone systems as, for example, by T1 lines in the telephone network. Essentially, AMI transmission systems have been widely employed in telephone as above indicated. In such a transmission system, frames are used as a means of setting up communication channels. This method of dividing frames into fields is sometimes referred to as PPM or pulse position modulation. The least number of fields within a frame is two. One field is used for framing and the other field contains some data. The least number of bits per channel within a frame is one. Essentially, frames are employed in AMI, Manchester and related bipolar transmission systems. The frames are delineated by intentionally violating a characteristic of the modulation or an encoding violation. As one can ascertain, a violation in AMI modulation occurs in various different instances.
An object of the present invention is to provide apparatus to determine the occurrence of a violation in a bipolar transmission system and to provide suitable signals upon the determination of such a violation.
The present invention provides apparatus to determine if an incoming AMI signal contains a bit which has been true for a specified period of time and to further determine if two or more bits have been received of the same polarity from AMI encoded data indicative of a violation.
It is therefore a further object of the present invention to provide a bit validation and start of frame detection apparatus for an AMI or bipolar transmission system.
SUMMARY OF THE INVENTION
Apparatus for detecting a code violation in an incoming bipolar information signal having different polarity pulses each of a given duration, comprising clock means for providing an output clock signal of a frequency greater than the frequency of said bipolar signal, counting means responsive to said incoming bipolar signal to count a predetermined number of one polarity levels of said bipolar signal with respect to said clock means to provide an output signal when said one polarity level does not change to another polarity level subsequent to obtaining a count of said predetermined number, and means responsive to said output signal from said counting means and to said bipolar information signal to detect a violation in said signal whereby said violation is indicative of said one polarity level followed by another said one polarity level in succession.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 consists of FIG. 1A-FIG. 1G constituting a series of waveforms necessary to explain the operation of the invention.
FIG. 2 is a circuit diagram showing an apparatus for separating an AMI signal into the positive and negative data signals.
FIG. 3 is a detailed block diagram of a frame detection circuit according to this invention.
FIG. 4 is a series of waveforms FIGS. 4A to 4F generated by the circuit of FIG. 3.
FIG. 5 is a series of waveforms FIGS. 5A to 5F necessary to explain operation of this invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1 there is shown a series of waveforms which will be employed in explaining the operation of the present invention. As indicated, frames in a bipolar transmission system as in an AMI system or, for example, a Manchester system are delineated by violating a characteristic of the modulation or the encoding. A violation in AMI modulation occurs when the polarity of the pulses remains the same for two or more pulses in succession. Frames in the AMI system are a fixed length and, for example, each frame may consist of 20 bits. The polarity of the violation varies based on the number of "1" bits contained in the frame. Therefore, it is necessary to test the status of the incoming data as a function of the data's polarity. In addition, it is necessary to insure that the information to be tested is valid. A method of validation is to test the duration of the incoming data. As will be explained, the circuitry according to this invention operates to do this.
Referring to FIG. 1A there is shown an AMI signal. FIG. 1A depicts the signal over 20 bits which constitutes one frame. As one can see, the 17th bit is a inverted signal or a "1" and then the 18th and 19th bits are at the zero reference level or logic "0" with the 20th bit also being a "1" but having a negative polarity and the same as the 17th bit. Thus as one can see, there is an encoding violation as successive "ones" are always of alternate polarity. Hence, two successive negative pulses cannot occur. Therefore the waveform of FIG. 1A shows a violation between the 17th and 20th bits because the polarity of the pulses remains the same for the configuration shown in FIG. 1A.
Referring to FIG. 1B there is again shown a frame or an incoming AMI signal. In FIG. 1B the 16th bit is positive and is then followed by another positive bit for the 20th bit with bits 17, 18, and 19 being at zero voltage or reference potential. Again, the waveform of FIG. 1B shows an improper AMI transition where the polarity of the pulses, namely the 16th and the 20th pulse, remains the same in succession. This also constitutes a violation in encoding, which can be used to determine the start of a frame (SOF).
Referring to FIG. 1C there is shown still another violation where another frame of 20 bits is shown. In FIG. 1C it is seen that the 16th bit and the 20th bit are both negative, with bits 17, 18, and 19 being at zero level, hence giving another violation which violation can constitute the start of a frame signal.
FIG. 1D shows a violation existing again in regard to bits 12 and 20, which are the same polarity level and not alternate polarity as required by the system's encoding.
One can see from the above that there are many types of violations which can exist and which can indicate a start of frame (SOF) or improper data and so on.
Referring to FIG. 1E there is shown a signal designated as P -- DATA. As one can see, the P -- DATA signal represents positive polarity data which exists on the AMI signal The P -- DATA signal of FIG. 1E corresponds to the AMI transmission as shown in FIG. 1D. Therefore for each positive pulse of FIG. 1D there is a positive pulse in FIG. 1E of the same duration.
FIG. 1F depicts an N -- DATA signal. As one can see from FIG. 1F, the signal N -- DATA represents negative polarity data taken from the bipolar encoded transmission system waveform (AMI) of FIG. 1D. The N -- DATA signal provides a positive pulse for each negative pulse of the AMI signal of FIG. 1D. The P -- DATA signal and the N -- DATA signal are combined in an OR gate or similar gate to form the signal shown in FIG. 1G. This signal is known as R -- DATA. As one can see the R -- DATA signal contains the ORed combination of P -- DATA and N -- DATA.
The circuit of FIG. 2 is a typical example of a circuit which can be employed to separate the P -- DATA and N -- DATA signals from the AMI signal and to combine them to provide the R -- DATA signal. As will be explained, the signals of FIG. 1E, 1F and 1G, namely the P -- DATA, N -- DATA and R -- DATA signals, are employed in conjunction with this invention to provide bit validation and start of frame detection circuit which is useful in the AMI transmission system.
It is noted that the apparatus of FIG. 2 is the subject matter of a co-pending U.S. application entitled APPARATUS FOR CONVERTING AN ALTERNATE MARK INVERSION SIGNAL TO UNIPOLAR SIGNALS filed on Dec. 28, 1990, Ser. No. 07/635,051 and assigned to the assignee herein U.S. Pat. No. 5,113,186.
Referring to FIG. 2 there is shown a circuit diagram depicting an alternate mark inversion to unipolar converter which can be employed to provide the P -- DATA, N -- DATA and R -- DATA signals. As seen in FIG. 2, an AMI signal as present on a telephone line is applied to the primary winding 20 of transformer T1. The primary winding 20 is conventionally protected by means of back to back Zener diodes or a diode network 21 to limit the magnitude of transients applied. Many protective devices are known and can be employed in lieu of network 21. The primary winding 20 is magnetically coupled to a secondary winding 22 which is shunted by means of a resistor 23 in shunt with a capacitor 24. Thus the AMI signal from the telephone line is isolated from the AMI converter to be described by means of the transformer T1. The back to back diode device 21 as indicated is a protective device to prevent incoming transients from damaging the electronic circuit on the other side of the transformer. The combination of resistor 23 in shunt with capacitor 24 is used for impedance matching. The secondary winding has one terminal coupled to reference potential and the other terminal coupled to the non-inverting input of an operational amplifier 25 arranged in a unity gain configuration. The operational amplifier 25 has its output coupled to the inverting terminal as is well known in the art. Essentially the operational amplifier 25 is arranged as a unity gain amplifier and used as an impedance transformer/buffer. Operational amplifiers are well known and many types can be employed for the circuit 25. The output of the unity gain amplifier 25 is directed to the inverting input terminal 28 of another operational amplifier 34 via a capacitor 26 in series with a resistor 27. The capacitor 26 and the resistor 27 appear in series and are shunted by means of a resistor 30. This network serves as the input impedance network (Z in ) for the amplifier 34. The network varies impedance with frequency as will be explained. The amplifier 34 has the non-inverting input returned to the point of reference potential via resistor 33. The output of amplifier 34 is coupled back to the input 28 through a feedback network which consists of resistor 40 in series with the parallel combination of inductor 31 and capacitor 32. The other terminal of inductor 31 and capacitor 32 is coupled to terminal 28 which, as indicated above, is the inverting input of amplifier 34. The amplifier 34 possesses a gain characteristic which is shown in FIG. 3 of the co-pending application depicting a plot of the impedance vs. frequency. As one can ascertain from FIG. 2, the inductance 31 in shunt with capacitor 32 forms an LC circuit which has a particular resonance. The point of resonance is selected to be significantly higher than the effective input frequency of the AMI signal. For a given gain bandwidth function the point of resonance would be selected to be much higher than this gain bandwidth factor. The amplifier 34 operates to compensate for the deterioration of the higher frequency components of the AMI signal due to transmission line losses and so on. Basically, resistor 30, resistor 27, and capacitor 26 form the input impedance circuit to the amplifier 34. The resistor 40, inductor 31, and capacitor 32 form the feedback path. Hence as is well known, the gain of an operational amplifier such as 34, follows the general equation. This gain is equal to the feedback impedance (Z f ) divided by the input impedance (Z in ) or Gain=Z f /Z in .
The impedance Z f of the tank circuit which essentially consists of inductor 31 and capacitor 32 increases as the frequency increases towards resonance but the value of the tank circuit is selected so that it does not reach resonance. The impedance Z in of the input circuit decreases as the input frequency increases based on the gain factor of the amplifier. Thus there is a marked increase in gain for the higher frequency components of the AMI signal. The output of the amplifier stage 34 is also directed to the non-inverting input of a first comparator 44 and to the inverting input of a second comparator 45. Comparator 44 and comparator 45 are operational amplifiers or comparators which receive a reference bias level from a voltage divider consisting of resistors 41, 42, and 43 coupled between a positive voltage source designated as +V and a negative voltage source designated -V. The value of the +V and -V sources can be +12 volts. The resistors are selected so that there is a fixed negative voltage applied to the non-inverting input of comparator 45 and an equal fixed positive voltage applied to the inverting input of comparator 44. The resistors 41, 42, and 43 are selected so that 41 may be equal to 10K, 42 equal to 4K, and 43 also equal to 10K. In this manner the stages form a bipolar to unipolar demodulator. The voltage levels at the inverting and non-inverting inputs of devices 44 and 45 respectively are selected to accommodate the noisy situation in which the system is specified to operate in. The output of amplifier 34 is coupled respectively to the non-inverting input of amplifier 44 and to the inverting input of amplifier 45. Therefore when the magnitude of the voltage applied to the non-inverting input of amplifier 44 exceeds the voltage at the inverting input, the output of amplifier 44 will rise to a TTL logical "1" level. Similarly, when the magnitude of the voltage applied to the inverting input of amplifier 45 exceeds the voltage at the non-inverting input of the amplifier, the output of the amplifier will rise to a TTL logical "1" level. The outputs remain at the logical "1" levels as long as the input voltage exceeds the respective magnitudes. The output of comparator 44 is referenced to a voltage level via resistor 46 as is the output of comparator 45 referenced to the same voltage level designated as +V/N via resistor 48. Thus the output of amplifier 44 produces P -- DATA as shown in FIG. 1E. The output of amplifier 45 provides N-DATA as shown in FIG. IF. The OR gate 47 receives the output from amplifiers 44 and 45 to produce the ORed output designated as R -- DATA and as shown in FIG. 1G.
As will be understood there are many other ways of separating the P -- DATA and N -- DATA signals from the AMI signal and other ways of forming the R -- DATA signal.
Referring to FIG. 3 there is shown a circuit schematic diagram of a bit validation and start of frame detection apparatus according to the principles of this invention.
As above indicated, a violation in AMI modulation occurs when the polarity of the pulses remains the same for two or more pulses in succession and as shown as violations for the signals shown in FIGS. 1A to FIG. 1D. Frames are of a fixed length as, for example, 20 bits. The polarity of the violation varies based on the number of "1" bits contained in the frame. Therefore it is necessary to test the status of the incoming data as a function of the data's polarity. In addition, it is necessary to insure that the information to be tested is valid. A method of validation is to test the duration of incoming data. Thus the circuitry shown in FIG. 3 provides a means of testing the data both for duration and polarity of the data. As seen in FIG. 3, the R -- DATA signal is applied to the clear input of a counter 50. The counter receives a master oscillator signal at the clock input. This frequency is selected to be much higher than the AMI rate and, for example, can be 10Mhz or greater. In this manner the counter 50 is used as a frequency divider and may provide a division by a suitable factor. The output of the counter is a signal designated as S -- CLK which signal is held off until the R -- DATA goes true. The S -- CLK frequency is such that three clock counts will be reached in about 50% of the true period of the incoming data. If reference is made to FIG. 4A, there is shown a P -- DATA signal which constitutes a half of a bit cell duration. FIG. 4B shows the S -- CLK signal. It is seen that the S -- CLK signal provides 6 pulses during the duration of the half bit cell or P -- DATA signal. The P -- DATA signal is applied to the clear (CLR) inputs of flip-flops 54 and 55 and is also applied to one input of AND gate 56. The flip-flops 54 and 55 are JK flip-flops. It is understood that other configurations could be employed as well. As seen in FIG. 3, flip-flops 54 and 55 are configured as a "Johnson" or ring counter. This type of counter provides a gray code counting method whereby one stage changes state at each S -- CLK input avoiding timing generated noise glitches. Thus as seen, the input to the counter which is the clock (CLK) inputs of the JK flip-flops 54 and 55 is obtained from the AND gate 52 having the S -- CLK signal applied to one input. Another AND gate 53 has one input coupled to the Q output of flip-flop 54 and one input coupled to the Q output of flip-flop 55. The purpose of gate 53 is to decode an output count of three from the counter. The output of gate 53 is coupled to the other input of AND gate 52. Thus when the output from AND gate 53 is low, this disables NAND gate 52 and therefore prevents any further S -- CLK signals from being applied to the counter consisting of JK flip-flops 54 and 55. If P -- DATA goes false prior to a count of three, the ring counter is held to its cleared position until the data goes true again. In this manner the counter is held to all zeros if the P -- DATA signal goes false prior to a count of three. In addition, the R -- DATA signal will also go false resetting counter 50. As will be further seen, this operation eventually causes the signal at the output of gates 60 and 59 which is designated as the start of frame (SOF) signal to fall very near the middle of the true period of the incoming data. The output signal from gate 59 is the start of frame (SOF) signal or a code violation signal and the output from inverter 60 is the inverse signal (SOF). As one can see, the Q outputs from flip-flops 54 and 55 are applied to a separate input of AND gate 56. AND gate 56 as indicated has four inputs. A first input to AND gate 56 is the P -- DATA signal. A second input to AND gate 56 is the output from gate 52 which is the S -- CLK. A third input to AND gate 56 is the Q output of flip-flop 54 and the fourth input to AND gate 56 is the Q output of flip-flop 55. The waveform at the output of AND gate 56 is shown in FIG. 4E. The Q output of flip-flop 54 is shown in FIG. 4C while the Q output of flip-flop 55 is shown in FIG. 4D. As seen AND gate 56 provides an output when counters 54 and 55 reach the count of three (1,1) and the S -- CLK and P -- DATA are "true" or at logic "1". Thus the output of gate 5 is positive if the data applied to the input remains true for a minimum of three counts. The Q output of JK flip-flop 57 is toggle true at the trailing edge of S -- CLK. This is shown in FIG. 4F which represents the Q output of flip-flop 57. The output of gate 56 is applied to the clock input (CLK) of flip-flop 57. The Q output of flip-flop 57 is applied to one input of AND gate 58 with the other input of AND gate 58 applied to the output of AND gate 56. The output of AND gate 58 is applied to one input of the OR gate 59. The output of OR gate 59 is the start of frame (SOF) signal or a code violation signal. The output of gate 59 is also applied to an inverter 60 to produce the negative or the SOF signal. As seen, the Q output of flip-flop 57 is applied to its own J and K inputs to prevent it from toggling once the Q output has gone false. The Q output of flip-flop 57 partially enables the AND gate 58. If the next incoming mark is the same polarity, while the Q output of flip-flop 57 is true, then the AND gate 58 is completely enabled for the duration of the positive period of the third S -- CLK. In this manner the SOF output of gate 59 will be generated both at the output of gate 59 and at the output of inverter 60, respectively. As one can see, the above-noted discussion concentrated upon circuit operation for the P -- DATA signal. Essentially the N -- DATA signal operation is implemented in the same exact manner. Thus the S -- CLK is again applied via gate 51 to the clock inputs of flip-flop 63 and 64 arranged in the same counting configurations as flip-flops 54 and 55. The N -- DATA signal is applied to the clear inputs of flip-flop 63 and 64. The flip-flops 63 and 64 have the count of 3 monitored by NAND gate 62 which has its output coupled to one input of 51 thereby disabling the same as above described for gates 52 and 53. The AND gate 65 has four inputs as gate 56 and operates in the same manner. In this manner AND gate 65 has a first input which is the Q output of flip-flop 54, a second input which is the Q output of flip-flop flop 63, a third input which is the output of gate 51 and a fourth input which is the N -- DATA input. The output of gate 65 is coupled to the clock input (CLK) of the toggle flip-flop 56 which operates in the same manner as flip-flop 57. The Q output of flip-flop 56 is coupled to one input of AND gate 68. The other input of gate 68 is coupled to the output of gate 65. The output of gate 68 is also coupled to the other input of OR gate 59 to generate an SOF signal for N -- DATA signal violations or negative pulse violations of the AMI signal. It is seen that inverters 61 and 67 operate to clear flip-flops 66 and 57 when P -- DATA or N -- DATA is controlling. Thus as seen, the above-noted circuit operates as the same way as the P -- DATA circuit except that the operation of, for example, the circuit containing counters 63 and 64 is for N -- DATA. Thus when consecutive marks or true periods are of the opposite polarity, flip-flops 57 and 66 are cleared. Assume now that flip-flop 57 has been set true by a P -- DATA mark. If the next true is generated from N -- DATA, the output of inverter 61 will go false clearing flip-flop 57, leaving the Q output from flip-flop 66 true. If the next mark is generated by P -- DATA, the output of inverter 67 will go false, clearing flip-flop 66. Therefore no SOF signal is generated. As an example, the period of an AMI bit cell at 160 kilobits per second is 6.250 microseconds. A logic "1" or mark condition is signified by the level remaining high for the first half of the cell period which is 3.125 microseconds. The objective is to have the third clock pulse fall in the center of this true period or about 1.56 microseconds into the period. Dividing the output of a 16 MHZ oscillator to 1.6 Mhz will cause this to occur. The SOF pulse will be 0.3125 microseconds wide. A narrow SOF pulse is beneficial if it is used as for example in a digital phase lock loop (DPLL). Wide pulses may hold counters and the like reset while the pulse is true. Thus, the circuit of FIG. 3 operates to do so.
FIG. 4A shows the typical one-half cell bit or the pulse duration for a P -- DATA or N -- DATA signal. FIG. 4B shows the S -- CLK si As one can see, there are six S -- CLK pulses within or N -- DATA pulse duration. This divides the duration by six. The number six is arbitrary and a greater or lesser number can be used. FIG. 4C shows the output of flip-flop 54. FIG. 4D shows the output of flip-flop 55. FIG. 4E shows the output of gate 56, and FIG. 4F shows the output of flip-flop 57.
Referring to FIG. 5, there is shown the above-noted data at a different scale where FIG. 5A shows a typical P -- DATA signal showing two pulses. FIG. 5B shows the nature of the S -- CLK signal. FIG. 5C shows the output of flip-flops 54 and/or 63. FIG. 5D shows the output of flip-flops 55 and/or 64. FIG. 5E shows the output of gates 56 and/or 65. FIG. 5F shows the output of OR gate 59. Thus, as one can understand, the above-described circuit tests the duration of the incoming bit to separate real data from noise pulses. The circuit operates to generate a narrow output pulse at the center of the true period of the bit cells reducing jitter and wandering while generating the narrow output pulse (SOF) which can control a digital phase lock loop. The count used to determine the true period of the bit can be increased such that the higher the count, the closer the output pulse will be to the center of the true period. The circuit operates to completely reset and start from zero if it is activated by noise pulses. The circuit as described above, operates to detect modulation errors by generating more or less frequent SOF outputs. | Apparatus is provided to provide a start of frame signal for an incoming bipolar information signal wherein one binary state is alternately encoded with positive and negative level pulses, each of a given duration, and the other binary state is encoded with a zero or reference level. The apparatus responds to said bipolar signal to provide a first series of pulses indicative of positive pulses and a second series of pulses indicative of negative pulses. A clock is provided which operates at a higher frequency than the bipolar signal. Counting means are provided and are responsive to said first and second signals and said clock to provide third and fourth signals each of said signals indicative of the true polarity of the input signal transitions to enable the processing of true data as compared to noise. The output of the counting means are coupled to logic means whereby if two or more successive pulses of the incoming signal have the same polarity, then a start of frame signal is provided by the logic means as coupled to the counting means. | 7 |
[0001] This invention relates to novel lactone compounds useful as monomers to form base resins for use in chemically amplified resist compositions adapted for micropatterning lithography, and methods for preparing the same.
BACKGROUND OF THE INVENTION
[0002] While a number of recent efforts are being made to achieve a finer pattern rule in the drive for higher integration and operating speeds in LSI devices, deep-ultraviolet lithography is thought to hold particular promise as the next generation in microfabrication technology. In particular, photolithography using a KrF or ArF excimer laser as the light source is strongly desired to reach the practical level as the micropatterning technique capable of achieving a feature size of 0.3 μm or less.
[0003] The resist materials for use in photolithography using light of an excimer laser, especially ArF excimer laser having a wavelength of 193 nm, are, of course, required to have a high transmittance to light of that wavelength. In addition, they are required to have an etching resistance sufficient to allow for film thickness reduction, a high sensitivity sufficient to eliminate any extra burden on the expensive optical material, and especially, a high resolution sufficient to form a precise micropattern. To meet these requirements, it is crucial to develop a base resin having a high transparency, rigidity and reactivity. None of the currently available polymers satisfy all of these requirements. Practically acceptable resist materials are not yet available.
[0004] Known high transparency resins include copolymers of acrylic or methacrylic acid derivatives and polymers containing in the backbone an alicyclic compound derived from a norbornene derivative. All these resins are unsatisfactory. For example, copolymers of acrylic or methacrylic acid derivatives are relatively easy to increase reactivity in that highly reactive monomers can be introduced and acid labile units can be increased as desired, but difficult to increase rigidity because of their backbone structure. On the other hand, the polymers containing an alicyclic compound in the backbone have rigidity within the acceptable range, but are less reactive with acid than poly(meth)acrylate because of their backbone structure, and difficult to increase reactivity because of the low freedom of polymerization. Additionally, since the backbone is highly hydrophobic, these polymers are less adherent when applied to substrates. Therefore, some resist compositions which are formulated using these polymers as the base resin fail to withstand etching although they have satisfactory sensitivity and resolution. Some other resist compositions are highly resistant to etching, but have low sensitivity and low resolution below the practically acceptable level.
SUMMARY OF THE INVENTION
[0005] An object of the invention is to provide a novel lactone compound useful as a monomer to form a polymer for use in the formulation of a photoresist composition which exhibits firm adhesion and high transparency when processed by photolithography using light with a wavelength of less than 300 nm, especially ArF excimer laser light as the light source. Another object is to provide a method for preparing the lactone compound.
[0006] We have found that a lactone compound of formula (1) can be prepared in high yields by a simple method to be described later, that a polymer obtained from this lactone compound has high transparency at the exposure wavelength of an excimer laser, and that a resist composition comprising the polymer as a base resin is improved in adhesion to substrates.
[0007] In one aspect, the invention provides a lactone compound of the following general formula (1).
[0008] Herein, k is 0 or 1 and m is an integer of 1 to 8.
[0009] In another aspect, the invention provides methods for preparing the lactone compound of formula (1).
[0010] A first method for preparing a lactone compound of formula (1) according to the invention involves the steps of reacting an oxirane compound of the following general formula (2) with a metallomalonate to form a hydroxy diester compound of the following general formula (3), followed by hydrolysis, decarboxylation and lactonization.
[0011] Herein, k and m are as defined above, R is alkyl such as methyl, ethyl or t-butyl, M is Li, Na, K, MgY or ZnY, and Y is halogen.
[0012] A second method for preparing a lactone compound of formula (1) according to the invention involves the steps of reacting an organometallic compound of the following general formula (4) with a 3-alkoxycarbonylpropionyl chloride to form a keto ester compound of the following general formula (5), followed by reduction and lactonization.
[0013] Herein, k, m, R and M are as defined above.
[0014] A third method for preparing a lactone compound of formula (1) according to the invention involves the steps of reacting an aldehyde compound of the following general formula (6) with lithium 3-lithiopropionate to form a hydroxycarboxylic acid compound of the following general formula (7), followed by lactonization.
[0015] Herein, k and m are as defined above.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0016] The lactone compounds of the invention are of the following general formula (1).
[0017] Herein k is 0 or 1 and m is an integer of 1 to 8 (i.e., 1≦m≦8).
[0018] Illustrative examples of the lactone compound are
[0019] It is believed that resist polymers obtained using these lactone compounds as the monomer exhibit good adhesion to substrates because the butyrolactone moiety regarded as a polar group that brings out adhesion is positioned at a site separated apart from the polymer backbone by an alkylene group. By selecting a lactone compound having an optimum alkylene chain as the monomer to form a polymer, the polymer as a whole can be adjusted to an appropriate compatibility and controlled in dissolution properties.
[0020] The lactone compounds of the invention can be produced by the following three methods, for example, but the invention is not limited to these methods.
[0021] The first method involves the steps of reacting an oxirane compound (2) with a metallomalonate to form a hydroxy diester compound (3), followed by hydrolysis, decarboxylation and lactonization, thereby producing the desired lactone compound (1).
[0022] Herein k and m are as defined above, R is an alkyl group such as methyl, ethyl or t-butyl, M is Li, Na, K, MgY or ZnY, and Y is a halogen atom.
[0023] The first step is to add a metallomalonate, prepared by a conventional method, to an oxirane compound (2) to form a hydroxy diester compound (3).
[0024] Ring opening of the oxirane ring occurs preferentially from the desired methylene terminal side over the sterically hindered methine side. The amount of metallomalonate used is preferably 0.9 to 3 mol, more preferably 1.0 to 1.8 mol per mol of the oxirane compound. Depending on reaction conditions, a solvent may be selected from ethers such as tetrahydrofuran, diethyl ether, di-n-butyl ether and 1,4-dioxane, hydrocarbons such as n-hexane, n-heptane, benzene, toluene, xylene and cumene, alcohols such as methanol, ethanol, isopropyl alcohol and tert-butyl alcohol, and polar aprotic solvents such as dimethyl sulfoxide and N,N-dimethylformamide, alone or in admixture of any. The reaction temperature and time vary over a wide range. In one example wherein sodium anions which are prepared from malonate and sodium alkoxide in dry alcohol are used as a reagent, the reaction temperature preferred for rapidly driving the reaction to completion is from room temperature to the reflux temperature, and especially from 50° C. to the reflux temperature. The reaction time is desirably determined by monitoring the reaction until the completion by gas chromatography (GC) or silica gel thin-layer chromatography (TLC) because higher yields are expectable. The reaction time is usually about 1 to about 20 hours. From the reaction mixture, the hydroxy diester compound (3) is obtained by a conventional aqueous work-up procedure. If necessary, the compound (3) may be purified by any conventional technique such as distillation, chromatography or recrystallization. Often the crude product has a sufficient purity as a substrate for the subsequent step and can be thus used in the subsequent step without purification.
[0025] The second step involves hydrolysis, decarboxylation and lactonization (dehydrative condensation) to yield the desired lactone compound (1).
[0026] In an example wherein the alkyl group of the malonate used is a primary alkyl group such as methyl or ethyl (that is, R=CH 3 or C 2 H 5 ), the ester is hydrolyzed or saponified using an aqueous alkaline solution, and then neutralized to form a hydroxy dicarboxylic acid. The resulting hydroxy dicarboxylic acid is converted to the lactone compound by heating in the presence of an acid catalyst to effect simultaneous decarboxylation and cyclization.
[0027] Herein, k and m are as defined above, and R is a primary alkyl group such as methyl or ethyl.
[0028] For the alkaline hydrolysis, use of aqueous solutions of hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide and barium hydroxide is preferred. The aqueous alkaline solution is preferably used in an amount of 2 to 10 mol, especially 2 to 4 mol per mol of the hydroxy diester compound (3). Alkaline hydrolysis can be effected in a solventless system although use may be made of organic solvents including ethers such as tetrahydrofuran, diethyl ether, di-n-butyl ether and 1,4-dioxane, alcohols such as methanol, ethanol, isopropyl alcohol and tert-butyl alcohol, and hydrocarbons such as n-hexane, n-heptane, benzene, toluene, xylene and cumene. The reaction temperature for alkaline hydrolysis is generally in the range of 0 to 100° C., and heating at a temperature of 50 to 100° C. is preferred to achieve rapid progress of reaction. Examples of the acid used for neutralization and decarboxylation/lactonization include inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid and nitric acid and organic acids such as oxalic acid, p-toluenesulfonic acid, and benzenesulfonic acid. As the acid catalyst for promoting decarboxylation/lactonization, the excess of acid left at the end of neutralization may be utilized or an acid of the same or different type may be newly added. In either case, the acid is used in an amount of 0.01 to 10 mol, especially 0.1 to 0.5 mol per mol of the hydroxy dicarboxylic acid. The reaction can be accelerated by positively removing the water formed upon lactone cyclization from the reaction system, for example, by azeotropical removal of water using a hydrocarbon such as n-hexane, n-heptane, benzene, toluene, xylene or cumene. Alternatively, the reaction may be carried out in vacuum in order to accelerate decarboxylation.
[0029] In another example wherein the alkyl group of the malonate used is a tertiary alkyl group such as tert-butyl (that is, R=t-C 4 H 9 ), elimination of the tertiary alkyl group, decarboxylation and lactonization (dehydrative condensation) can be carried out simultaneously under acidic conditions, not by way of alkaline hydrolysis.
[0030] Herein, k and m are as defined above, and R is a tertiary alkyl group such as t-butyl. (R—H) is an alkene corresponding to the alkyl group R from which a hydrogen atom is eliminated. For example, (R—H) is isobutene when R is t-butyl.
[0031] Herein, an acid selected from inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid and nitric acid and organic acids such as oxalic acid, p-toluenesulfonic acid, and benzenesulfonic acid is used in an amount of 0.01 to 10 mol, preferably 0.1 to 0.5 mol per mol of the hydroxy diester compound. The reaction can be accelerated by positively removing the water formed upon lactone cyclization from the reaction system, for example, by azeotropical removal of water using a hydrocarbon such as n-hexane, n-heptane, benzene, toluene, xylene or cumene. Alternatively, the reaction may be carried out in vacuum in order to accelerate decarboxylation.
[0032] From the reaction mixture, the target lactone compound (1) is obtained by a conventional aqueous work-up step. If necessary, the compound (1) can be purified by any conventional technique such as distillation, chromatography or recrystallization.
[0033] In the second method, the desired lactone compound (1) is prepared by reacting an organometallic compound (4) with a 3-alkoxycarbonylpropionyl chloride to form a keto ester compound (5), followed by reduction and lactonization (dehydrative condensation).
[0034] Herein, k, m, R and M are as defined above.
[0035] The first step is to react an organometallic compound (4) with a 3-alkoxycarbonylpropionyl chloride in a solvent to form a keto ester compound (5).
[0036] It is important at this stage that reaction takes place preferentially at the acid chloride site rather than at the ester site of the 3-alkoxycarbonylpropionyl chloride. This is accomplished by properly selecting the type of organometallic reagent, catalyst and reaction conditions.
[0037] The organometallic compound is prepared by a conventional method from a corresponding halogen compound or by transmetallation from an organometallic reagent of different metal. The solvent may be selected in accordance with reaction conditions from ethers such as tetrahydrofuran, diethyl ether, di-n-butyl ether and 1,4-dioxane, hydrocarbons such as n-hexane, n-heptane, benzene, toluene, xylene and cumene, and polar aprotic solvents such as dimethyl sulfoxide and N,N-dimethylformamide, alone or in admixture of any. There may be used as an auxiliary a compound having a ligand such as N,N,N′,N′-tetramethylethylenediamine (TMEDA), hexamethylphosphoric triamide (HMPA), N,N′-dimethylpropyleneurea (DMPU) or 1,3-dimethyl-2-imidazolidinone (DMI). The catalyst which can be used is selected from compounds of transition metals such as iron, copper, palladium, nickel, cadmium and vanadium. An appropriate amount of the 3-alkoxycarbonylpropionyl chloride used is 1.0 to 5 mol, preferably 1.3 to 2 mol per mol of the organometallic reagent.
[0038] Reaction conditions vary over a wide range depending on the combination of reagent, solvent and catalyst. In one example using tetrahydrofuran as the solvent and a Grignard reagent (corresponding to M=MgY) as the organometallic compound, in the absence of the transition metal catalyst, reaction is effected at a low temperature, specifically −78° C. to room temperature, and especially −70° C. to 0° C. In this example, dropwise addition of the Grignard reagent to the 3-alkoxycarbonylpropionyl chloride solution, known as reverse addition, is effective. In another example using tetrahydrofuran as the solvent, a Grignard reagent (corresponding to M=MgY) as the organometallic compound, and an iron salt (e.g., Fe(acac) 3 ) as the transition metal catalyst in a catalytic amount (e.g., 0.01 to 0.5 mol per mol of the Grignard reagent), reaction is effected at a temperature of −10° C. to 50° C., and especially 0° C. to 30° C. In a further example using tetrahydrofuran or N,N-dimethylformamide as the solvent, an organozinc reagent (corresponding to M=ZnY) as the organometallic compound, and a palladium compound (e.g., Pd(PPh 3 ) 4 ) or nickel compound (e.g., NiCl 2 (dppp)) as the transition metal catalyst in a catalytic amount (e.g., 0.01 to 0.5 mol per mol of the organozinc reagent), reaction is effected at a temperature of 0° C. to 80° C., and especially room temperature to 50° C. In a still further example using a Grignard reagent (corresponding to M=MgY) or organic lithium reagent (corresponding to M=Li) as the organometallic compound, and a cuprous salt (e.g., CuCl or CuBr) as the transition metal catalyst in a stoichiometric amount (e.g., 1.0 to 2.0 mol per mol of the organometallic reagent), reaction is effected at a temperature of 0° C. to 80° C., and especially room temperature to 50° C. The reaction time is desirably determined by monitoring the reaction until the completion by GC or silica gel TLC because higher yields are expectable. The reaction time is usually about 1 to about 20 hours.
[0039] From the reaction mixture, the keto ester compound (5) is obtained by a conventional aqueous work-up procedure. If necessary, the end compound (5) is purified by any conventional technique such as distillation, chromatography or recrystallization. If the crude product has a sufficient purity as a substrate for to the subsequent step, it can be used in the subsequent step without purification.
[0040] The second step involves reduction and lactonization of the keto ester compound (5) to the desired lactone compound (1).
[0041] First referring to the reduction of keto group, it is important to selectively reduce only the keto group without reducing the ester group.
[0042] For the reduction of keto group, various reducing agents may be used. Often metal hydrides are preferably used in solvents. Exemplary metal hydrides are complex hydrides and alkoxy or alkyl derivatives thereof, including sodium borohydride, lithium borohydride, potassium borohydride, calcium borohydride, sodium aluminum hydride, lithium aluminum hydride, sodium trimethoxyborohydride, lithium trimethoxyaluminum hydride, lithium diethoxyaluminum hydride, lithium tri-t-butoxyaluminum hydride, sodium bis(2-methoxyethoxy)aluminum hydride, and lithium triethylboron hydride. The reducing agent is often used in an amount of 1.0 to 8.0 mol, preferably 1.0 to 1.5 mol of hydride per mol of the keto ester compound. The solvent may be selected in accordance with reaction conditions from water and various organic solvents including ethers such as tetrahydrofuran, diethyl ether, di-n-butyl ether and 1,4-dioxane, hydrocarbons such as n-hexane, n-heptane, benzene, toluene, xylene and cumene, alcohols such as methanol, ethanol, isopropyl alcohol and tert-butyl alcohol, and aprotic polar solvents such as dimethyl sulfoxide and N,N-dimethylformamide, alone or in admixture of any.
[0043] Reaction temperature and time vary over a wide range depending on the particular starting materials used. For example, when reduction is effected with lithium aluminum hydride in tetrahydrofuran, preferred reaction conditions include use of lithium aluminum hydride in a stoichiometric or slightly excess amount (1.0 to 1.05 equivalent as hydride) in order to avoid further reduction, a reaction temperature in the range of −80° C. to 0° C., and a reaction time of about 0.1 to 1 hour. From the reaction mixture, the hydroxy ester compound is obtained by conventional work-up. If necessary, the product may be purified by any conventional technique such as distillation, chromatography or recrystallization. If the crude product has a sufficient purity as a substrate for the subsequent step, it can be used in the subsequent step without purification. The hydroxy ester compound thus obtained is then converted to the desired lactone compound (1).
[0044] Herein, the hydroxy ester compound can be converted to the lactone compound by hydrolyzing or saponifying the ester with an aqueous alkaline solution, then neutralizing it to form a hydroxy carboxylic acid, and heating the hydroxycarboxylic acid in the presence of an acid catalyst to effect dehydrative condensation. Alternatively, the hydroxy ester compound can be converted to the lactone compound by heating it in the presence of an acid catalyst to effect alcohol-eliminating condensation. To these reactions, the same procedure as the step of converting the hydroxy diester compound (3) to the lactone compound (1) in the first method is applicable.
[0045] In the third method, the lactone compound (1) is prepared by reacting an aldehyde compound (6) with lithium 3-lithiopropionate to form a hydroxycarboxylic acid compound (7), followed by lactonization (dehydrative condensation).
[0046] Herein k and m are as defined above.
[0047] The first step is to react an aldehyde compound (6) with lithium 3-lithiopropionate to form a hydroxycarboxylic acid compound (7).
[0048] Lithium 3-lithiopropionate (dianion) is prepared by treatment of a 3-halopropionic acid with a base in a solvent. Examples of the 3-halopropionic acid are 3-bromopropionic acid and 3-iodopropionic acid. Examples of the base include lithium amides such as lithium diisopropylamide, lithium 2,2,6,6-tetramethylpiperidine, lithium bistrimethylsilylamide and lithium isopropylcyclohexylamide; alkyl lithium compounds such as trityllithium, methyllithium, phenyllithium, sec-butyllithium and tert-butyllithium; and lithium hydride. The solvent is selected in accordance with reaction conditions from ethers such as tetrahydrofuran, diethyl ether, di-n-butyl ether and 1,4-dioxane, hydrocarbons such as n-hexane, n-heptane, benzene, toluene, xylene and cumene, and polar aprotic solvents such as dimethyl sulfoxide and N,N-dimethylformamide, alone or in admixture of any. There may be used as an auxiliary a compound having a ligand such as N,N,N′,N′-tetramethylethylenediamine (TMEDA), hexamethylphosphoric triamide (HMPA), N,N′-dimethylpropyleneurea (DMPU) or 1,3-dimethyl-2-imidazolidinone (DMI).
[0049] The lithium 3-lithiopropionate thus prepared is used in an amount of 0.7 to 3 mol, preferably 1.0 to 1.3 mol per mol of the aldehyde compound (6) for addition reaction to take place. Since the lithium 3-lithiopropionate is unstable at high temperature, the reaction is preferably effected under cooling, especially at a temperature of −78° C. to 0° C. The reaction time is desirably determined by monitoring the reaction until the completion by GC or silica gel TLC because higher yields are expectable. The reaction time is usually about 0.2 to about 2 hours. From the reaction mixture, the hydroxycarboxylic acid compound (7) is obtained by a conventional aqueous work-up step. If necessary, the compound (7) may be purified by any conventional technique such as distillation, chromatography or recrystallization. If the crude product has a sufficient purity as a substrate for the subsequent step, it can be used in the subsequent step without purification.
[0050] The second step involves lactonization (dehydrative condensation) of the hydroxycarboxylic acid compound (7) to the desired lactone compound (1).
[0051] The hydroxycarboxylic acid compound can be converted to the lactone compound by heating it in the presence of an acid catalyst to effect dehydrative condensation. To this reaction, the same procedure as the step of converting the hydroxy dicarboxylic acid compound to the lactone compound (1) in the first method is applicable.
[0052] A polymer is prepared using the inventive lactone compound as a monomer. The method is generally by mixing the monomer with a solvent, adding a catalyst or polymerization initiator, and effecting polymerization reaction while heating or cooling the system if necessary. This polymerization reaction can be effected in a conventional way. Exemplary polymerization processes are ring-opening metathesis polymerization, addition polymerization, and alternating copolymerization with maleic anhydride or maleimide. It is also possible to copolymerize the lactone compound with another norbornene monomer.
[0053] A resist composition is formulated using as a base resin the polymer resulting from polymerization of the lactone compound. Usually, the resist composition is formulated by adding an organic solvent and a photoacid generator to the polymer and if necessary, further adding a crosslinker, a basic compound, a dissolution inhibitor and other additives. Preparation of the resist composition can be effected in a conventional way.
[0054] The resist composition formulated using the polymer resulting from polymerization of the inventive lactone compound lends itself to micropatterning with electron beams or deep-UV rays since it is sensitive to high-energy radiation and has excellent sensitivity, resolution, and etching resistance. Especially because of the minimized absorption at the exposure wavelength of an ArF or KrF excimer laser and firm adhesion to the substrate, a finely defined pattern having sidewalls perpendicular to the substrate can easily be formed. The resist composition is thus suitable as micropatterning material for VLSI fabrication.
EXAMPLE
[0055] Synthesis Examples and Reference Examples are given below for further illustrating the invention. It is not construed that the invention be limited to these examples.
[0056] Synthesis Examples are first described. Lactone compounds within the scope of the invention were synthesized in accordance with the following formulation.
Synthesis Example 1
Synthesis of γ-(5-norbornen-2-yl)methyl-γ-butyrolactone (Monomer 1)
[0057] In a nitrogen atmosphere, a solution in 300 g dry tetrahydrofuran of a Grignard reagent prepared from 50.0 g of 5-bromomethyl-2-norbornene by a conventional technique was added to a mixture of 47.2 g of 3-methoxycarbonyl-propionyl chloride, 4.61 g of iron (III) acetylacetonate, and 300 ml of dry tetrahydrofuran at 10° C., which was stirred for 2 hours. Then 100 g of 10% hydrochloric acid was added to stop the reaction, whereupon hexane was added for extraction. The organic layer was washed with water and aqueous saturated sodium bicarbonate solution, and concentrated in vacuum, obtaining a keto ester. The keto ester was dissolved in 100 g of tetrahydrofuran, to which 80 g of water, 5.06 g of sodium boron hydride and 10 g of methanol were successively added. The mixture was stirred for 12 hours at 20° C. for effecting reduction to a hydroxy ester. Then 50 g of 20% hydrochloric acid was added to the reaction mixture, which was stirred for one hour for lactonization. This was followed by hexane extraction, washing with water, washing with aqueous saturated sodium bicarbonate solution, and vacuum concentration. Purification by silica gel column chromatography yielded 42.1 g (yield 82%) of γ-(5-norbornen-2-yl)methyl-γ-butyrolactone.
[0058] IR (thin film): ν=3057, 2962, 2939, 2866, 1774, 1336, 1217, 1180, 1020, 978, 912 cm −1
[0059] [0059] 1 H-NMR of major endo-isomer (270 MHz in CDCl 3 ): δ=0.54 (1H, m), 1.15-1.45 (3H, m), 1.45-1.95 (3H, m), 2.15-2.40 (2H, m), 2.40-2.60 (2H, m), 2.70-2.85 (2H, m), 4.46 (1H, m), 5.90 (1H, m), 6.13 (1H, m).
Synthesis Example 2
Synthesis of γ-(5-norbornen-2-yl)methyl-γ-butyrolactone (Monomer 1)
[0060] In 80 g of dry tetrahydrofuran was dissolved 10.0 g of 3-bromopropionic acid. In a nitrogen atmosphere, 85.0 g of a hexane solution of 1.6M n-butyllithium was added to the solution at −78° C., followed by 30 minutes of stirring. Then a solution of 8.92 g 2-(5-norbornen-2-yl)acetaldehyde in 20 g hexamethylphosphoric triamide was added dropwise to the solution at the same temperature. With stirring, the temperature of the solution was gradually raised to 20° C. over 2 hours. Next, 80 g of 5% hydrochloric acid was added to the solution, which was stirred for one hour for lactonization. The organic layer was separated, washed with aqueous saturated sodium bicarbonate solution, washed with water, and concentrated in vacuum. Purification by silica gel column chromatography yielded 8.17 g (yield 65%) of γ-(5-norbornen-2-yl)methyl-γ-butyrolactone. The analytical properties of this compound were substantially identical with the data of Synthesis Example 1.
Synthesis Example 3
Synthesis of γ-2-(5-norbornen-2-yl)ethyl-γ-butyrolactone (Monomer 2)
[0061] In a nitrogen atmosphere, 1.84 g of metallic sodium was dissolved in 100 g of dry ethanol. Then 13.0 g of diethyl malonate was added to the solution, which was heated under reflux for one hour, forming the sodium salt of diethyl malonate. Then 11.2 g of 1,2-epoxy-4-(5-norbornen-2-yl)butane was added to the solution, which was heated under reflux for 4 hours, forming a hydroxy diester compound. Then 130 g of a 5% aqueous sodium hydroxide solution was added to the solution, which was heated under reflux for 4 hours to effect hydrolysis. The ethanol was distilled off, and 100 g of toluene and 60 g of 20% hydrochloric acid were added to the residue, which was stirred for one hour for lactonization, forming a lactone carboxylic acid. The organic layer was separated and concentrated in vacuum. Decarboxylation reaction was effected at 140° C. and 8,000 Pa. Subsequent vacuum distillation yielded 12.6 g of γ-2-(5-norbornen-2-yl)ethyl-γ-butyrolactone (boiling point: 122-127° C./67 Pa, yield: 89%).
[0062] IR (thin film): ν=3055, 2960, 2937, 2864, 1776, 1456, 1352, 1219, 1180, 1018, 982, 912 cm −1
[0063] [0063] 1 H-NMR of major endo-isomer (270 MHz in CDCl 3 ): δ0.49 (1H, m), 1.00-1.90 (8H, m), 1.97 (1H, m), 2.28 (1H, m), 2.45-2.55 (2H, m), 2.70-2.80 (2H, m), 4.42 (1H, m), 5.89 (1H, m), 6.11 (1H, m).
Synthesis Example 4
Synthesis of γ-2-(5-norbornen-2-yl)ethyl-γ-butyrolactone (Monomer 2)
[0064] In a nitrogen atmosphere, 11.2 g of potassium t-butoxide was dissolved in 250 g of dry tetrahydrofuran. Then 21.0 g of di-t-butyl malonate and 8.0 g of 1,2-epoxy-4-(5-norbornen-2-yl)butane were successively added to the solution, which was heated under reflux for 10 hours. The reaction solution was neutralized with 100 g of a 10% aqueous acetic acid solution, and extracted with ethyl acetate, whereupon the extracted solution was washed with water and concentrated in vacuum, obtaining a hydroxy diester compound. The hydroxy diester compound was dissolved in 200 g of toluene, which was combined with 1.0 g of p-toluenesulfonic acid and heated under reflux for 10 hours for effecting ester decomposition, lactonization and decarboxylation reaction. The reaction mixture was washed with water and concentrated in vacuum. Purification by vacuum distillation yielded 6.00 g (yield 60%) of γ-2-(5-norbornen-2-yl)ethyl-γ-butyrolactone. The analytical properties of this compound were substantially identical with the data of Synthesis Example 3.
Synthesis Example 5
Synthesis of γ-{5-(5-norbornen-2-yl)-1-pentyl}-γ-butyrolactone (Monomer 3)
[0065] In a nitrogen atmosphere, a solution in 300 g dry tetrahydrofuran of a Grignard reagent prepared from 91.8 g of 5-(5-chloro-1-pentyl)-2-norbornene by a conventional technique was added to a suspension of 69.3 g zinc chloride in 200 g dry tetrahydrofuran, forming an organozinc reagent. In the nitrogen atmosphere, the organozinc reagent was added to a mixture of 83.5 g of 3-methoxycarbonylpropionyl chloride, 5.0 g of tetrakis(triphenylphosphine)palladium(0), and 200 g of dry tetrahydrofuran at 20° C., which was stirred for 4 hours. Then 500 g of 10% aqueous ammonium chloride solution was added to stop the reaction, followed by hexane extraction, water washing and vacuum concentration, obtaining a keto ester compound. The keto ester compound was subjected to reduction, lactonization and purification as in Synthesis Example 1, yielding 97.5 g (yield 85%) of γ-{5-(5-norbornen-2-yl)-1-pentyl}-γ-butyrolactone.
[0066] IR (thin film): δ=3057, 2933, 2860, 1778, 1460, 1346, 1219, 1180, 1124, 1018, 978, 914 cm −1
[0067] [0067] 1 H-NMR of major endo-isomer (300 MHz in CDCl 3 ): δ=0.46 (1H, m), 0.95-2.00 (15H, m), 2.30 (1H, m), 2.40-2.60 (2H, m), 2.65-2.80 (2H, m), 4.46 (1H, m), 5.88 (1H, m), 6.08 (1H, m).
[0068] The structural formulas of Monomers 1 to 3 are shown below.
Reference Example
[0069] Polymers were synthesized using the lactone compounds obtained in the above Synthesis Examples. Using the polymers as a base resin, resist compositions were formulated, which were examined for substrate adhesion.
[0070] Polymerization reaction of tert-butyl 5-norbornene-2-carboxylate, Monomer 1, and maleic anhydride was effected using an initiator V65 (Wako Junyaku K.K.), yielding an alternating copolymer of tert-butyl 5-norbornene-2-carboxylate/γ-(5-norbornen-2-yl)methyl-γ-butyrolactone/maleic anhydride (copolymerization ratio 4/1/5).
[0071] A resist composition was prepared by blending 80 parts by weight of the above copolymer as a base resin, 1.0 part by weight of triphenylsulfonium trifluoromethanesulfonate as a photoacid generator, 480 parts by weight of propylene glycol monomethyl ether acetate as a solvent, and 0.08 part by weight of tributylamine. The composition was spin coated on a silicon wafer having hexamethyldisilazane sprayed thereon at 90° C. for 40 seconds and heat treated at 110° C. for 90 seconds, forming a resist film of 500 nm thick. The resist film was exposed to KrF excimer laser light, heat treated at 110° C. for 90 seconds, and developed by immersing in a 2.38% tetramethylammonium hydroxide aqueous solution for 60 seconds, thereby forming a 1:1 line-and-space pattern. The wafer as developed was observed under SEM, finding that the pattern down to 0.26 μm size was left unstripped.
Comparative Reference Example
[0072] For comparison purposes, a resist composition was prepared as above, using an alternating copolymer of tert-butyl 5-norbornene-2-carboxylate/maleic anhydride (copolymerization ratio 1/1). It was similarly processed, and examined for substrate adhesion. No patterns with a size of 0.50 μm or less were left.
[0073] It was confirmed that polymers resulting from the inventive lactone compounds have significantly improved substrate adhesion as compared with prior art polymers.
[0074] Japanese Patent Application No. 2000-205217 is incorporated herein by reference.
[0075] Although some preferred embodiments have been described, many modifications and variations may be made thereto in light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described without departing from the scope of the appended claims. | Lactone compounds of formula (1) are novel and useful as monomers to form base resins for use in chemically amplified resist compositions adapted for micropatterning lithography.
Letter k is 0 or 1 and m is an integer of 1-8. | 2 |
BACKGROUND OF THE INVENTION
This invention relates to an improved method and apparatus for forming a scrim with fibers oriented in the bias direction.
A scrim is defined as a fabric with an open construction used as a base fabric in the production of coated or laminated fabrics. Previously, machines utilized to form a scrim use a chain in which the fibers are passed through the links on the chain. This restricts the number of fibers to an even multiple to the number of links on the chain. Changing the number of fibers used requires adding or removing chain links and other adjustments for proper operation.
In addition, the previous machines utilized for forming a scrim require a chain to rotate with the creel. The linear velocity of the chain could become excessively large if the fibers in the scrim are nearly transverse.
Another major drawback to the previous machines utilized for forming a scrim is that when using a chain, there is a minimum limit to the number of chain links needed to form a continuous loop of chain as well as the length of each chain length is also constricted by a minimum value. As the length of chain is decreased, the chordal action of the chain around the respective sockets becomes more pronounced. The variation in velocity brought about by the chordal action of the chain can cause slack regions within the scrim.
The present invention solves the above problems in a manner not disclosed in the known prior art.
SUMMARY OF THE INVENTION
A method and apparatus for forming a scrim with fibers oriented in the bias direction comprising of at least two belts and at least one plate which forms a three dimensional mandrel over which the bias scrim is formed. The plate is shaped so that any cross-section taken perpendicularly to the direction of travel of the scrim, the perimeter of the scrim formed by fibers wrapped around the machine in the plane of the cross-section is constant. This constant is equal to twice the final width of the scrim from selvedge to selvedge. The scrim is formed by wrapping fibers around the front of the assembly while the belts move toward the rear end of the machine. The movement of the belts carries the fibers to the rear of the assembly as they are wrapped around the assembly. The belts travel at substantially the same speed in opposite directions. The ratio of the speed that the fibers are wrapped around the assembly and the speed of the belts determines the fiber angle of the bias scrim. This fiber angle can be varied continuously from transverse to nearly longitudinal. The bias angle can be varied while the assembly is operating.
An advantage of this invention is that any number of fibers may be used to make a scrim with nearly any bias angle without any modification of the assembly.
It is another advantage of this invention to be able to change the number of fibers by merely adding spools or bobbins to a rotating creel.
Yet another advantage of this invention is to be able to change the bias angle merely by changing the rotation of the creel and the speed of the belts.
Still another advantage of this invention is that the number of fibers utilized in the scrim can be changed without removing chain links or other complicated adjustments.
Another advantage of this invention is that this assembly can be operated at very high speed that can be substantially the same speed as the web speed.
Yet another advantage of this invention is that very narrow scrims can be created with the minimum size of the scrims limited to the thickness of the belts.
In another aspect of this invention is that slack regions around the scrim can be eliminated.
These and other advantages will be in part obvious and in part pointed out below.
BRIEF DESCRIPTION OF THE DRAWINGS
The above as well as other objects of the invention will become more apparent from the following detailed description of the preferred embodiments of the invention, which when taken together with the accompanying drawings, in which:
FIG. 1 is a schematic side elevational view of the apparatus constructed according to the present invention including creel take-off, adhesive application, drying and take-up;
FIG. 2 is a top plan view of the apparatus constructed according to the present invention with rotating creel assembly and opposed compression rolls;
FIG. 3 is a right side perspective view of the apparatus constructed according to the present invention including top and bottom covers and opposed compression rolls;
FIG. 4 is a cross-sectional view taken on Line 3--3 of FIG. 3;
FIG. 5 is a view corresponding to FIG. 4 only utilizing an alternative embodiment as a drive mechanism for the belts;
FIG. 6 is an isolate perspective view of the upper gear drive mechanism detailed in FIG. 5;
FIG. 7 is an isolated perspective view of the lower belt drive mechanism detailed in FIG. 5;
FIG. 8 is an isolated perspective view of a flat belt;
FIG. 9 is an isolated perspective view of a flat belt having cylindrical protrusions extending therefrom;
FIG. 10 is an isolated perspective view of a ladder-type chain belt; and
FIG. 11 is an isolated perspective view of a cross-type chain belt.
Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now by reference numerals to the drawings, and first to FIG. 1, a creel is generally indicated by numeral 10. The creel 10 is comprised of preferably at least nine yarn packages 12 with the number of yarn packages 12 varying greatly depending on scrim construction. The yarn packages 12 are positioned on stationary shafts 14 that are attached to the back support member 16 that is attached to a circular support plate 22. There is also a vertical front plate 26 attached to the circular support plate 22. This vertical front plate 26 has openings 29 that guide yarns 28 from the yarn packages 12 and through a circular creel ring 30 and then onto the scrim forming apparatus that is generally denoted by numeral 32. The circular creel ring 30 is attached to the vertical front plate 26 by means of upper and lower support members 36 and 34, respectively.
The creel 10 rotates by means of an upper support bearing 18 and a lower support bearing 19 that are attached to the main vertical creel support member 20. There must be at least three support bearings even though only two are shown in FIG. 1. There are also two ancillary yarn packages 39, with only one being shown in FIG. 1, attached to a support 37. A support and guide means for yarn 43 is designated by numeral 41. The two yarns 43 and 44 associated with ancillary yarn packages 39, as best shown in FIG. 2, form the selvedge for the formed scrim that is designated by numeral 45. After the scrim 45 is formed by the scrim forming apparatus 32, which will be disclosed in greater detail hereinafter, the scrim 45 then is compressed by means of both an upper compression roll 50 and a lower compression roll 52, as shown in FIG. 1. The scrim 45 is then padded with an adhesive by means of upper padding roll 54 and lower padding roll 56. The lower padding roll 56 is submerged in a tray of adhesive 58. A wide variety of adhesives will suffice such as polyvinyl alcohol, polyvinyl chloride, among others. The formed scrim 45 then travels over a steam can 60 to dry the adhesive at a temperature in the range of 200 to 350 degrees Fahrenheit and then through upper and lower drive rolls 62 and 64, respectively and then onto take-up roll 66.
The scrim forming apparatus 32 is further detailed in FIGS. 2, 3 and 4. The primary operating mechanism comprises of a first endless belt 68 and a second endless belt 69 that rotate at relatively the same speed and in opposite directions for guiding the yarns as well as at least one plate for forming a three-dimensional mandrel over which the bias scrim is formed. In FIGS. 2-5, the first endless belt 68 is located on the right and the second endless belt 69 is located on the left. In the preferred embodiment, there should be both a first plate and a second plate, designed on the left by numeral 71 and on the right by numeral 72, respectively, as shown in FIG. 3. The first plate 71 and second plate 72 are shaped so that at any cross section taken perpendicular to the direction of travel of the scrim 45, the perimeter formed by a yarn 28 wrapped around the scrim-forming apparatus 32 in the plane of the cross-section is a constant equal to twice the final width of the scrim 45, from selvedge yarn 43 to selvedge yarn 44. The purpose of maintaining a constant perimeter for the length of the machine is to prevent any of the yarns 28 forming the scrim 45 from becoming slack or excessively taut.
The scrim 45 is formed by the yarns 28 dispensed from the circular creel ring 30 that maintains tension on the yarns 28 and wraps the yarns 28 around the front of the scrim forming apparatus 32. The movement of first endless belt 68 and second endless belt 69 carries the yarns 28 toward the rear of the scrim forming apparatus 32 as the yarns 28 are wrapped around the scrim forming apparatus 32.
Referring now to FIGS. 3 and 4, there is a first sprocket 75 and a second sprocket 76 associated with the first endless belt 68. Second sprocket 76 is attached to second plate 72 by means of a combination bracket and sprocket assembly 78. There are two hexagonal cap screws 216 and 217 that attach the bracket to the second plate 72 by means of threaded attachment to lower rear plate assemblies 96 and 97, respectively. There are two hexagonal cap screws 218 and 219 that attach the bracket to the sprocket assembly. All components utilized throughout this Application are preferably formed of aluminum, however, a wide variety of metals, plastics, composites, and so forth will suffice. Attachment is preferably accomplished by means of hexagonal cap screws, however, a wide variety of attachment means will suffice including mechanical means, adhesives, welding, brazing, and so forth. There is a top sprocket bracket assembly 80 and a bottom sprocket bracket assembly 81 that attach to first sprocket 75. Top sprocket bracket assembly 80 attaches to a front block 86, which is located between second plate 72 and first plate 71, by hexagonal cap screw 220. Bottom sprocket bracket assembly 81 also attaches, by hexagonal cap screw 221, to front block 86. Front block 86 is located between second plate 72 and first plate 71 and attached thereto as shown on the right side by hexagonal cap screws 251 and 252, respectively. Additional support members located between second plate 72 and first plate 71 include front upper plate assembly 90 and corresponding front lower plate assembly 91, as shown in FIG. 4. Additional support members located between first plate 71 and second plate 72 and are attached thereto include a front middle member 92, a rear middle member 94 and an upper and lower rear plate assemblies 96 and 97, respectively. Front upper plate assembly 90 and corresponding front lower plate assembly 91 are attached to front middle member 92 and front spacer block 86 by means of hexagonal cap screws (not shown). First endless belt 68 encircles a first endless belt support 99 that maintains tension in first endless belt 68 and prevents the first endless belt 68 from necking inward while preserving the shape thereof. There is a front first endless belt support bracket 101 and a rear first endless belt support bracket 102 that connects the first endless belt support 99 to second plate 72. This is accomplished in the first leg of the front first endless belt support bracket 101 by means of hexagonal cap screws 210 and 211 through second plate 72 and threadedly attached to front middle member 92. The second leg of the front first endless belt support bracket 101 is attached to the first endless belt support 99 by means of hexagonal cap screw 212. This identical arrangement is replicated with the rear first endless belt support bracket 102 with hexagonal cap screws 213 and 214 through second plate 72 and threadedly attached to rear middle member 94. The second leg of the rear first endless belt support bracket 102 is attached to the first endless belt support 99 by means of hexagonal cap screw 215.
Correspondingly, as shown in FIG. 4, there is a third sprocket 105 and a fourth sprocket 106 associated with the second endless belt 69. As shown in FIG. 3, fourth sprocket 106 is attached to first plate 71 by means of a combination bracket and sprocket assembly 108 in the same manner as combination bracket and sprocket assembly 78. Sprocket assembly 108 is attached to lower rear plate assembly 96 by means of a hexagonal cap screw (not shown) through first plate 71. There is a top sprocket bracket assembly 110 and a bottom sprocket bracket assembly 111, which both attach to third sprocket 105 in the same manner as the top and bottom sprocket bracket assembly 80 and 81, respectively. Top sprocket bracket assembly 110 attaches to front spacer block 86 that is located between first plate 71 and second plate 72. Bottom sprocket bracket assembly 111 attaches to front spacer block 86 that is located between first plate 71 and second plate 72 and attached thereto. As best illustrated in FIG. 4, second endless belt 69 encircles second endless belt support 113 that maintains tension in second endless belt 69 and prevents the second endless belt 69 from necking inward while preserving the shape thereof. There is a front second endless belt support bracket 115 and a rear second endless support bracket 117 that connect the belt support 113 to first plate 71 in the same manner as rear and front first endless belt support brackets 101 and 102, respectively. Front second endless belt support bracket 115 is attached to front middle member 92 by means of dual hexagonal cap screws (not shown) through first plate 71. Rear second endless belt support bracket 115 is attached to rear middle member 94 by means of dual hexagonal cap screws (not shown) through first plate 71.
The internal drive mechanism is generally indicated by numeral 120, as shown in FIG. 4, comprising of an input drive shaft 122 that is held in rotatable position by front bearing 124 and rear bearing 126. There is a coupling mechanism 151 that extends the input drive shaft 122 and attaches thereto by means of threaded screws 153 and 152, respectively. Front bearing 124 is held in position by front spacer block 86, as shown in FIG. 3.
As shown in FIG. 4, rear bearing 126 is held in position by first middle member 92 having an aperture 128 to accommodate the rear bearing 126 and a smaller aperture 130 to allow the input drive shaft 122 to rotate freely. Between front bearing 124 and rear bearing 126, a worm drive 132 encircles the input drive shaft 122 and is moved in fixed relation thereby. This worm drive 132 turns first worm wheel 134 clockwise and second worm wheel 136 counterclockwise. As shown in FIG.4, the first worm wheel 134 is located on the left and the second worm wheel 136 is located on the right. First worm wheel 134 is fixedly attached to first drive sprocket 138 and the second worm wheel 136 is fixedly attached to second drive sprocket 140. There is first secondary drive belt 142 that is attached to the first drive sprocket 138 and connects to a first secondary drive sprocket 145. The first secondary drive sprocket 145 is fixedly attached to third sprocket 105. Therefore, worm drive 132 rotating clockwise moves first worm wheel 134 clockwise thereby moving first drive sprocket 138 clockwise and thereby moving first secondary drive belt 142 clockwise, thereby moving first secondary drive sprocket 145 clockwise as well as third sprocket 105 which moves second endless belt 69 in a clockwise rotation thereby moving the scrim from the front to the rear of the scrim forming apparatus 32.
There is also a second secondary drive belt 143 that is attached to the second drive sprocket I40. As previously stated, the second drive sprocket 140 is fixedly attached to the second worm wheel 136. Therefore, worm drive 132 rotating clockwise moves second worm wheel 136 counterclockwise, thereby moving second drive sprocket 140 counterclockwise and thereby moving second secondary drive belt 143 counterclockwise, thereby moving second secondary drive sprocket 146 counterclockwise as well as first sprocket 75 which moves first endless belt 68 in a counterclockwise rotation thereby moving the scrim from the front to the rear of the scrim forming apparatus 32.
As shown in FIG. 3, just prior to exiting the scrim forming apparatus 32, the spread passes over a triangular scrim plate 162 that is attached between upper rear spacer block 96 and lower rear spacer block 97 by means of hexagonal cap screw 222. As shown in FIG. 4, attached to the outer opposed ends of the triangular spread plate 162 are a first gear 156 and associated first gear bearing 159 and second gear 157 and associated second gear bearing 160. The first gear 156 and second gear 160 are designed to engage the scrim 45. The scrim 45 then travels through the upper and lower compression rolls 50 and 52, respectively, as shown in FIG. 3. There is an upper cover 167 and a lower cover 166 that conform to the outside of the scrim forming apparatus 32 in order to keep the scrim 45 isolated from any outside interference or contamination.
An alternative means of driving first endless belt 68 and second endless belt 69 with the internal drive mechanism 120 found at the front of the scrim forming apparatus 32, and parallel to the longitudinal axis thereof, is found in FIG. 5 and involves the replacement of the internal drive mechanism 120 with two drive units located substantially perpendicular to the longitudinal axis of the scrim forming apparatus 32. The first drive unit is located near the front of the scrim forming apparatus and generally indicated by numeral 170. There is a first input drive shaft 173 connected to a first coupling unit 175 that is attached to a first drive shaft 177 by means of hexagonal cap screws 265 and 266, respectively. The first drive shaft 177 extends on both sides of the scrim forming apparatus 32. The first drive shaft 177 passes through a first right angle drive translator 180 and is in mechanical interengagement therewith and having a first drive translator gear 179, having an associated first shaft and bearing assembly 181. The first drive translator gear 179 engages the outside of the first endless belt 68 and rotates the first endless belt 68 in a counterclockwise rotation. As shown in FIG. 7, the first drive translator gear 179 and the first endless belt 68 allow the scrim 45 to move therebetween without damage to the scrim 45. This is accomplished by means of a relief groove cut into the teeth of first drive translator gear 179 which allows passage of selvedge 43 therebetween without damage. The first drive shaft 177 also connects to a second right angle drive translator 183 and is in mechanical interengagement therewith and having a second drive translator gear 184, having an associated second shaft and bearing assembly 185. The second drive translator gear 184 engages the outside of the second endless belt 69 and rotates the second endless belt 69 in a clockwise rotation. As with the first drive translator gear 179, the second drive translator gear 184 and the second endless belt 69 allow the scrim 45 to move therebetween without damage to the scrim 45. The second drive unit is located near the rear of the scrim forming apparatus 32 and generally indicated by numeral 171. There is a second input drive shaft 190 connected to a second coupling unit 191 that is attached to a second drive shaft 192 by means of hexagonal cap screws 277 and 278, respectively. The second drive shaft 192 extends on both sides of the scrim forming apparatus 32. The second drive shaft 192 passes through a third right angle drive translator 194 and is in mechanical interengagement therewith and having a third drive translator gear 195, having an associated third shaft and bearing assembly 196, which engages the outside of first gear 156 and rotates first gear 156 in a counter-clockwise rotation. As shown in FIG. 6, the third drive translator gear 195 and first gear 156 allow the scrim to move therebetween without damage to the scrim 45. There is a small groove cut into the teeth of the third drive translator gear 195 and first gear 156 to prevent the selvedge yarn 43 from being cut up. The second drive shaft 192 also connects to a fourth right angle drive translator 198 and is in mechanical interengagement therewith and having a fourth drive translator gear 199, having an associated fourth shaft and bearing assembly 200, which engages the outer left side of second gear 157 and rotates second gear 157 in a clockwise rotation. As with the third drive translator gear 195, the fourth drive translator gear 199 and second endless belt 69 allow the scrim 45 to move therebetween without damage to the scrim 45.
With the exception of the drive means, the alternative embodiment of FIG. 5 is substantially similar to FIG. 4 with identical numerical designations to reflect such similarity. It should be noted that with both embodiments, first sprocket 75, second sprocket 76, third sprocket 105 and fourth sprocket 106 must be of the type required to engage first endless belt 68 and second endless belt 69.
There are several embodiments of the type of the first and second endless belts 68, 69 that could create the scrim 45 as part of the scrim forming apparatus 32. A flat belt can be utilized, as shown in FIG. 8, and designated by numeral 201. It is understood that there should be a significant degree of friction on the surface of flat belt 201 in order for belt 201 to move the scrim 45. Another embodiment is to utilize a flat belt 201 with cylindrical protrusions 203 projecting from one side, as shown in FIG. 9 and generally indicated by numeral 202. Each yarn 28 will then be separated from each other to insure high quality scrim formation.
A third embodiment of the first or second endless belt 68, 69 is to use a series of cylindrical members 204 that are perpendicularly interconnected by a series of upper linking members 205 located near the top of the cylindrical members 204 and a series of lower linking members 206 located near the bottom of the cylindrical members 204. Upper linking members 205 are in parallel relationship to lower linking members 206 and in conjunction with cylindrical members 204 form a ladder-type chain generally indicated by numeral 207.
A fourth embodiment of the first or second endless belt 68, 69 is to use a series of cylindrical members 204 similar to that found in the previous embodiment that are interconnected by a single series of perpendicular linking members 230 located near the middle of the series of cylindrical members 204 as shown in FIG. 11. This cross-type chain is generally indicated by numeral 231.
It is not intended that the scope of the invention be limited to the specific embodiment illustrated and described. Rather, it is intended that the scope of the invention be defined by the appended claims and their equivalents. | A method and apparatus for forming a scrim with fibers oriented in the bias direction comprising of at least two belts and at least one plate which forms a three dimensional mandrel over which the bias scrim is formed. The plate is shaped so that any cross-section taken perpendicularly to the direction of travel of the scrim, the perimeter of the scrim formed by fibers wrapped around the machine in the plane of the cross-section is constant. This constant is equal to twice the final width of the scrim from selvedge to selvedge. The scrim is formed by wrapping fibers around the front of the assembly while the belts move toward the rear end of the machine. The movement of the belts carry the fibers to the rear of the assembly as they are wrapped around the assembly. The belts travel at substantially the same speed in opposite directions. The ratio of the speed that the fibers are wrapped around the assembly and the speed of the belts determine the fiber angle of the bias scrim. This fiber angle can be varied continuously from transverse to nearly longitudinal. The bias angle can be varied while the assembly is operating. | 3 |
BACKGROUND
[0001] The present invention relates to a transmission device, and more particularly to a transmission device for protecting a transmission bus of a communication system and a control method thereof.
[0002] Computer systems comprise many integrated circuits (ICs), such as microprocessors, random access memories (RAMs), electrically erasable programmable read only memories (E 2 PROMs), liquid crystal display (LCD) drivers, or data converters. These ICs transmit data through a bus, such an as an inter-integrated circuit (I 2 C) bus.
[0003] FIG. 1 is a schematic diagram of a conventional I 2 C connecting integrated circuits. Integrated circuits (ICs) 11 ˜ 14 transmit data through the I 2 C bus 15 . Only utilizing clock signal SCL and data signal SDA is characteristic of the I 2 C bus 15 .
[0004] In an I 2 C bus, only one IC is designated as a master for controlling the clock signal SCL and others are designated as slave ICs. The master IC is unfixed such that each IC can be designated as a master IC.
[0005] If the IC 11 is designated as a master, ICs 12 - 14 serve as slave ICs. Some factors, such as element aging, may cause the IC 11 abnormal such that the IC 11 outputs an incorrect clock signal SCL to hold the I 2 C bus 15 . Therefore, ICs 11 ˜ 14 cannot transmit data to each other and the computer system paralysis causes shutdown.
[0006] In actual operation, since many ICs are connected via the I 2 C bus 15 , when the status of one IC is abnormal, a user cannot easily and directly find the abnormal IC. A conventional solution has been developed. First, a user opens a computer case and then finds the I 2 C bus. Next, the ICs are pulled by the user.
[0007] When pulling out one IC, a user must test the operation of the I 2 C bus. If the I 2 C bus is still paralyzed, a user must continue pulling out other ICs until the paralysis is eliminated. If the number of abnormal ICs exceeds one, the user must insert the removed ICs and then pull the ICs out one by one, until all the abnormal ICs are found. This conventional solution is costly, time consuming and requires human intervention.
SUMMARY
[0008] Embodiments of the invention provide a communication system comprising a transmission bus, a plurality of circuit apparatuses and a management device. Each circuit apparatus comprises an external integrated circuit and a switch circuit. Each external integrated circuit is coupled to the transmission bus via the corresponding switch circuit. The management device monitors the status of the transmission bus. When the status of the transmission bus is determined as abnormal, the management device switches at least one of the switch circuits to isolate at least one corresponding external integrated circuit from the transmission bus.
[0009] Also provided is a transmission device transmitting data between a plurality of external integrated circuits. The transmission device comprises a transmission bus, a plurality of external connectors, and a management device. Each external connector comprises a slot and a switch circuit. Each external integrated circuit is able to couple to the transmission bus via one slot and the corresponding switch circuit. The management device monitors the status of the transmission bus. When the status of the transmission bus is determined as abnormal, the management device switches at least one of the switch circuits to isolate at least one corresponding external integrated circuit from the transmission bus.
[0010] An embodiment of the invention additionally provides a control method, appropriate for a communication system comprising a transmission bus and a plurality of integrated circuits. A plurality of switch circuits are provided. Each switch circuit connects between the transmission bus and a corresponding integrated circuit. The status of the transmission bus is monitored. At least one switch circuit is switched to isolate at least one corresponding integrated circuit from the transmission bus and to retrieve a failed integrated circuit when the status is determined as abnormal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The invention can be more fully understood by reading the subsequent detailed description and examples with reference made to the accompanying drawings, wherein:
[0012] FIG. 1 is a schematic diagram of a conventional I 2 C connecting integrated circuits;
[0013] FIG. 2 is a schematic diagram of a communication system according to an embodiment of the invention;
[0014] FIG. 3 shows a control method of a computer system according to an embodiment of the invention.
DETAILED DESCRIPTION
[0015] A bus interface, such as a system management bus (SM Bus), a universal controller interface bus (USB), a IEEE1394, a peripheral controller interface bus (PCI Bus), and an I 2 C bus, can be applied in the invention. Hereinafter, an I 2 C bus is given as an example.
[0016] FIG. 2 is a schematic diagram of a communication system according to an embodiment of the invention. The communication system 20 comprises integrated circuits (ICs) 11 ˜ 14 and a transmission device 22 . ICs 11 ˜ 14 transmit data through the transmission device 22 .
[0017] The transmission device 22 comprises an I 2 C bus 15 , slots 241 ˜ 244 , switch circuits 261 ˜ 265 , and a management device 280 . ICs 11 ˜ 14 can be inserted into slots 241 ˜ 244 to connect with the I 2 C bus 15 through switch circuits 261 ˜ 265 , respectively.
[0018] The management device 280 is connected with the I 2 C bus 15 through switch circuit 265 for monitoring the status of the I 2 C bus 15 and switching the switch circuits 261 ˜ 265 . Since the management device 280 continuously or periodically monitors the status of the I 2 C bus 15 , the switch circuit 265 is generally turned on. The I 2 C bus 15 is coupled to terminals of the ICs 11 ˜ 14 , transmitting the clock signal SCL and data signal SDA.
[0019] When the management device 280 determines the status of the I 2 C bus 15 as abnormal, for example the voltage level of the clock signal SCL or data signal SDA has not been changed during a preset time or the ICs are unable to transmit data through the I 2 C bus 15 , the management device 280 switches the switch circuits 261 ˜ 264 individually to isolate a corresponding IC from the I 2 C bus 15 . Once one of switch circuits 261 ˜ 264 is turned off and the I 2 C bus 15 is normal, it may be concluded that a corresponding isolated IC has failed. A failed IC can be isolated, in order to not disturb the signal transmission of others.
[0020] When the switch circuits 261 ˜ 264 are all turned off and the status of the I 2 C bus 15 is abnormal, it is possible that the root cause of abnormality is in the management device 280 or I 2 C bus 15 itself. Thus, the switch circuit 265 can be turned off and if the ICs 11 ˜ 14 are still unable to transmit data through the I 2 C bus 15 , it can be determined that the failed has occurred in the I 2 C bus 15 .
[0021] When the failed factor is detected, the management device 280 generates a warning signal, such as an alarm or a catchphrase, to notify user of the failed.
[0022] If a failed IC has been isolated from the I 2 C bus 15 , the operation of the I 2 C bus 15 should resume normal operation even if the user does not immediately remove the abnormal IC. Additionally, the I 2 C bus 15 of the present invention has a hot-swap function such that a user can immediately swap the failed IC when it is detected.
[0023] The operating principle of the management device 280 is shown in FIG. 2 and described in the following. FIG. 3 shows a control method of a communication system according to an embodiment of the invention. The ICs 11 ˜ 14 are inserted into the slots 241 ˜ 244 , respectively. The switch circuits 261 ˜ 265 are initially turned on.
[0024] First, the management device 280 monitors the status of the I 2 C bus 15 in step 100 . If the status of the I 2 C bus 15 is normal, the ICs 11 ˜ 14 may transmit data to each other. After another period of time, the management device 280 monitors the status again.
[0025] When the status of the I 2 C bus 15 is monitored as being abnormal, the communication system is determined as being blocked. The management device 280 begins to switch the switch circuits 261 ˜ 264 to locate and isolating a failed IC in step 200 .
[0026] In step 210 , the management device 280 turns off all switch circuits 261 ˜ 264 for isolating the ICs 11 ˜ 14 from the I 2 C bus 15 such that the status of the I 2 C bus 15 is again normal.
[0027] Following step 210 , if I 2 C bus 15 becomes normal, the management device 280 detects the first IC, and a parameter n is set to 1 in step 220 . The management device 280 turns on first switch circuit 261 in step 230 for connecting the first IC with the I 2 C bus 15 . The management device 280 monitors the status of the I 2 C bus 15 in step 240 . If the status of the I 2 C bus 15 is still normal, the management device 280 increases the parameter n in step 250 and turns on the next switch circuit in step 230 . From parameter n, the management device 280 or a system supervisor can determine which switch circuit is being switched and make record if needed.
[0028] Every time when one switch circuit is turned on, the corresponding IC is connected to the I 2 C bus 15 and the management device 280 then monitors the status of the I 2 C bus 15 . If the status of the I 2 C bus 15 becomes abnormal due to the newly-added connection, the management device 280 turns off the switch circuit for isolating the corresponding IC in step 260 , in order to maintain the normal status of the I 2 C bus 15 .
[0029] Finally, the management device 280 detects whether the last switch circuit has been switched in step 270 . If the last switch circuit has been switched, the management device 280 stops controlling the switch circuits and the process returns to step 100 . If the last switch circuit is not switched, the management device 280 increases the parameter n in step 250 for turning on the next switch circuit.
[0030] For example, in FIG. 2 , ICs 11 ˜ 14 are connected to the I 2 C bus 15 , a failure occurs in the IC 13 , and the status of the I 2 C bus 15 is abnormal.
[0031] When the abnormal status is detected by the management device 280 , switch circuits 261 ˜ 264 are turned off causing the status of the I 2 C bus 15 to recover normal status. The management device 280 then sequentially turns on switch circuits 261 ˜ 264 . The management device 280 detects the status of the I 2 C bus 15 each time a switch circuit is turned on. When the switch circuit is turned on and the status of the I 2 C bus 15 is still normal, the management device 280 continues to turn on another switch circuit.
[0032] Since the IC 13 has failed, when the management device 280 turns on the switch circuit 263 , the I 2 C bus 15 becomes abnormal and this abnormality can be detected by the management device 280 . Accordingly, the management device 280 turns off the switch circuit 263 . When the failed IC is isolated, the status of the I 2 C bus 15 must turn back to normal. After the management device 280 turns on the switch circuit 264 , data can be transmitted in the I 2 C bus 15 .
[0033] In addition to the described sequential search method, the management device 280 can utilize a binary search method to select switch circuits. First, the switch circuits are divided into two groups. One group is turned off and the other is turned on. If the status of the I 2 C bus 15 is detected as normal, a failed IC in the group must be turned off. If the status of the I 2 C bus 15 is abnormal, the failed IC is in the turned on group.
[0034] To allocate the failed IC, the group causing the abnormal status is further divided into two sub-groups. The management device 280 continues to detect which sub-group is causing the communication system to fail. This binary search method can narrow the detection range. Finally, when a group has only one switch circuit, the failed one is located.
[0035] Advantages of embodiments of the invention are summarized in the following. First, the invention controls switch circuits and auto-detects the status of the bus such that the failed IC is located. Embodiments of the invention can shorten detection time and reduce cost by utilizing different control methods. Second, when the failed IC is located, the failed IC can be isolated from the bus, allowing the bus to again function normal. Third, since the invention auto-isolates the failed IC, a user need not remove the failed IC immediately and the bus is available.
[0036] While the invention has been described by way of example and in terms of the preferred embodiments it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements. | A communication system. The system includes a transmission bus, a plurality of circuit apparatuses, and a management device. Each circuit apparatus comprises an external integrated circuit and a switch circuit. Each external integrated circuit is coupled to the transmission bus via the corresponding switch circuit. The management device monitors the status of the transmission bus and, when the status is determined as abnormal, switches at least one of the switch circuits to isolate at least one corresponding external integrated circuit from the transmission bus. | 6 |
RELATED APPLICATION
[0001] This is a divisional application of U.S. patent application Ser. No. 10/435,554 filed on May 12, 2003.
BACKGROUND OF THE INVENTION
[0002] This invention relates to electrical machines having centrally disposed stators and, in particular, to liquid-cooled alternators having centrally disposed stators.
[0003] Liquid-cooled generators, particularly alternators, are well known in the prior art. Many of the units are relatively large and complicated. It would be desirable to provide liquid-cooled generators or alternators for much smaller applications.
[0004] It is often of importance to obtain the highest possible efficiency when generating electricity by capturing and utilizing energy losses which occur during the process. In the case of a conventional generator, these losses are mostly waste heat which are usually vented out of the generator by means of a blower.
[0005] Such a blower draws in dirt and debris which are detrimental to the life of the bearings of the generator and may cause a fire in the generator. The air stream also carries noise from the engine-generator assembly. This noise may be difficult to dampen without disturbing the air stream or significantly increasing the size of the enclosure of the generator sets to allow for sound traps.
[0006] Liquid-cooled generators have been suggested in the past, for example in U.S. Pat. No. 6,046,520 to Betsch et al. In this example a conventional generator is surrounded by a housing and a liquid coolant is circulated in a space between the housing and the generator. The bulk of the generator is increased by the presence of the housing and water tightness of the generator is required.
[0007] Another liquid-cooled electrical machine is disclosed in U.S. Pat. No. 6,072,253 to Harpenau. As is typical of generators, the stator is on the outside and has cooling tubes connected thereto. The provision for cooling in the stator and the connections for the coolant increase the size of the machine.
[0008] Another such generator is disclosed in U.S. Pat. No. 6,160,332 to Tsuruhara. In this example a brushless generator has magnets on the centrally disposed rotor. The cooling chamber again is on the outside and extends about the exterior stator.
[0009] Despite the prior art, there is still a significant need for a compact liquid-cooled generator where the design is simple enough to minimize the cost of manufacture and, accordingly, the sale price.
[0010] It is an object of the invention to provide an improved electrical machine which is simple and compact and yet provides the benefits of liquid-cooling.
[0011] It is another object of the invention to provide a generator which can operate without bearings.
[0012] It is a still further object of the invention to provide an improved generator which has fewer parts than a conventional generator and requires less precision during manufacture and assembly.
SUMMARY OF THE INVENTION
[0013] There is provided, according to one aspect of the invention, an electrical machine having a centrally disposed stator with stator windings. There is a rotor mounted on a rotatable member for rotation therewith. The rotor extends about the stator.
[0014] There is provided, according to another aspect of the invention, a liquid-cooled electrical machine having a centrally disposed stator with stator windings. There is a rotor mounted on a rotatable member for rotation therewith. The rotor extends about the stator. A cooling chamber is disposed within the stator and has an inlet for a coolant and an outlet for the coolant connected thereto.
[0015] There is provided, according to a further aspect of the invention, a combination engine and electrical machine mounted thereon. The engine may be an internal combustion engine, an external combustion engine such as a steam engine or in general any rotating engine which has a flywheel. The electrical machine includes a centrally disposed stator having stator windings. A rotor is mounted on a rotatable member for rotation therewith.
[0016] There is provided, according to a still further aspect of the invention, a combination internal combustion engine and liquid-cooled electrical machine mounted thereon. The liquid-cooled electrical machine includes a centrally disposed stator having stator windings. A rotor is mounted on a rotatable member for rotation therewith. The rotor extends about the stator. A cooling chamber is disposed within the stator and has an inlet for a coolant and an outlet for the coolant connected thereto.
[0017] The invention offers significant advances compared to the prior art. It yields a compact electrical machine, in particular an alternator, where the stator is located centrally with the rotor extending about the stator, instead of the conventional opposite arrangement. This allows for a simplified and compact structure, particularly for liquid-cooled alternators.
[0018] Such electrical machines can be compact in size to fit in the location of a conventional air-cooled alternator. Moreover, noise is reduced compared with such air-cooled alternators and contamination by dirt and debris can be effectively eliminated. This is because the alternator can be fully enclosed.
[0019] The invention allows for the elimination of rear engine seals since the alternator or generator can be flushed with motor oil, thereby reducing a failure mode whereby the main seal leaks due to wear. Furthermore a diesel engine starter can be eliminated by using the generator as a motor to start the engine, thus reducing cost as well as enabling the complete sealing of the engine since it does not need access to the flywheel. Elimination of the flywheel on a diesel engine is also possible since the starter motor may be eliminated and the mass of the generator may be used instead of the flywheel.
[0020] Moreover, such a generator can be built without bearings and with fewer parts than a conventional generator. Less precision is required during manufacture and assembly since lineup is not critical. Thus the cost of the product can be significantly reduced.
[0021] The heat removed from the generator is not wasted. Instead the heated coolant can be used for useful purposes such as heating passenger compartments of vehicles. Thus the overall energy efficiency is increased.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In drawings which illustrate embodiments of the invention:
[0023] FIG. 1 is a cross-section of a liquid-cooled alternator according to an embodiment of the invention;
[0024] FIG. 2 is a view similar to FIG. 1 of an alternative embodiment;
[0025] FIG. 3 is a sectional view of the stator thereof taken along line 3 - 3 of FIG. 2 ;
[0026] FIG. 4 is a sectional view, similar to FIG. 1 , of a further embodiment of the invention; and
[0027] FIG. 5 is a simplified side elevation, partly broken away, of the embodiment of FIG. 4 mounted on an engine.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] Referring to the drawings and first to FIG. 1 , this shows an electrical machine 20 in the form of the generator, in particular an alternator, designed for use in conjunction with engine 22 which in this embodiment is an internal combustion engine although the invention is also applicable to other rotating engines including external combustion engines such as steam engines. The electrical machine acts not only as a generator, but also operates as a flywheel, replacing the conventional flywheel. FIGS. 2 and 3 illustrate an alternative embodiment where like parts have like numbers with the addition of “ 0 . 1 ”. Likewise FIGS. 4 and 5 show a further alternative embodiment where like parts have like numbers with the addition of “0.2”.
[0029] Referring back to FIG. 1 , engine 22 acts as a support for housing 24 which is nonmetallic in this example. The housing is of glass fiber reinforced plastic in this example although other materials could be substituted. The housing is connected to the engine by a plurality of bolts 26 . The engine is equipped with a flywheel 28 . The flywheel supports a rotor 30 which rotates with the flywheel. As seen in FIG. 1 , the rotor is cantilevered from the flywheel and is connected to the flywheel by a plurality of bolts 32 . The rotor is annular in shape and has a plurality of permanent magnets 34 connected to inside surface 36 thereof. The quantity and orientation of the magnets, together with the rotational speed of the flywheel, determine the type of current that the generator produces. In one example 54 magnets in a two-pole arrangement are rotated at 3600 rpm to yield conventional 50 Hz AC current. If the rotational speed is 3000 rpm, then a 60 Hz current is produced. The rotational speed may be lower, for example 1800 rpm, and still produce a 50 Hz current, but the magnets are arranged in a four-pole pattern. This same pattern produces a 50 Hz current when the rotational speed is 1500 rpm.
[0030] The generator is equipped with an annular stator 56 which, in this example, is a laminated stator with copper windings 58 . Leads 64 extend outwardly through aperture 66 in the housing. The stator is supported by hollow cylindrical protrusion 70 which forms part of a cup-like casing 71 for a coolant chamber 72 . In this example the stator is connected to the casing by means of a plurality of bolts 74 although alternatively it may be press fitted onto protrusion 70 . Where the fit is loose, it is beneficial to place thermal conductive grease on mating surfaces between the stator and the protrusion to ensure proper heat transfer. Increased heat transfer is achieved by way of annular surface 76 of the stator contacting annular surface 78 of the casing.
[0031] A cover 80 is connected to the housing by a plurality of bolts 82 . A watertight seal is ensured by O-ring 83 . An inlet nipple 86 and outlet nipple 84 serve as fittings for feeding coolant into the chamber and for discharging coolant from the chamber respectively. There is a tube 90 connected to the inlet nipple 86 and which projects into the protrusion 70 to prevent coolant from short-circuiting from the inlet nipple to the outlet nipple.
[0032] The chamber is cooled by a liquid coolant 94 circulated by means of an external pump, not shown. The flow direction is indicated by arrow 96 . The flow of coolant through the chamber cools the generator by removing heat created by the stator.
[0033] It may be observed that no bearings are required in the generator. The rotor is entirely supported by the flywheel 28 .
[0034] Referring to FIG. 2 , generator 20 . 1 is generally similar to the embodiment above, but stator 56 . 1 in this example is not laminated, but is made of a watertight material such as Anchor Steel™ or a similar particular magnetic powder metal which has magnetic properties similar to a laminated stator core. Because the stator is watertight, a separate casing is not required, but rather the chamber is formed by internal cavity 96 in the stator together with cavity 98 in housing 24 . 1 . A plurality of spaced apart fins 100 are formed on inside surface 36 . 1 of the stator to improve heat transfer between the coolant and the stator.
[0035] Referring to FIG. 3 , stator 56 . 1 illustrates the fins 100 as well as slots 102 for receiving the windings 58 . 1 . Also shown are threaded apertures 104 which receive the bolts 82 . 1 .
[0036] FIGS. 4 and 5 show a further embodiment of the invention where rotor 30 . 2 is mounted directly on crankshaft 110 of engine 22 . 2 and forms the flywheel for the engine. The housing 24 . 2 is formed in part by an annular extension 116 of the engine block with a plate 112 connected thereto by a plurality of bolts 114 . The rotor/flywheel is magnetic, having a magnetic north pole 120 and a south pole 122 . The stator and chamber arrangements are similar as in the previous embodiment. The oil in the engine may be allowed to splash into the rotor area as an additional cooling device and to cool the conventional seal around the crankshaft/turboshaft. No bearings are required apart from the normal crankshaft bearings 130 , 132 and 134 . Shaft seals are not required since the crankshaft does not extend outside engine block 111 .
[0037] All of the above embodiments work in a similar manner. As the rotor rotates, it creates a rotating magnetic field. The rotating field cuts the windings on the stator and an alternating current is induced. Waste heat from the generation of the current is captured by the circulating coolant and is pumped away, preferably for use as a source of heat.
[0038] Generators according to the invention may also be wound for multiple voltages on the same unit. This eliminates the need for power transformers on the vehicle to power lower voltage equipment.
[0039] It will be understood by someone skilled in the art that many of the details provided above are by way of example only and can be altered or deleted without departing from the scope of the invention which is to be interpreted with reference to the following claims. | An internal combustion engine has a liquid-cooled electrical machine mounted thereon. The liquid-cooled electrical machine includes a centrally disposed stator having stator windings. A rotor is mounted on a rotatable member for rotation therewith. The rotor extends about the stator. A cooling chamber is disposed within the stator and has an inlet for a coolant and an outlet for the coolant connected thereto. | 7 |
BACKGROUND
A concern for many business enterprises is proper utilization of computational resources. In a fast changing business environment, an enterprise can go from having too much computational capacity to having too little in a short period of time. Having too much computational capacity causes a business enterprise to waste resources, while having too little capacity can cause a business enterprise to lose potential business opportunities.
BRIEF DESCRIPTION OF THE DRAWINGS
For a detailed description of exemplary embodiments of the invention, reference will now be made to the accompanying drawings in which:
FIG. 1 shows an application trace for a first application in accordance with an embodiment of the invention;
FIG. 2 shows an application trace for a second application in accordance with an embodiment of the invention;
FIG. 3 shows an application trace for a third application in accordance with an embodiment of the invention;
FIG. 4 shows a graph illustrating how a principal component is found in accordance with an embodiment of the invention;
FIG. 5 shows a scree plot in accordance with an embodiment of the invention;
FIG. 6 shows a graph of a reconstructed trace for the trace shown in FIG. 1 in accordance with an embodiment of the invention;
FIG. 7 shows a graph of a reconstructed trace of the trace shown in FIG. 2 in accordance with an embodiment of the invention;
FIG. 8 shows a graph of a reconstructed trace of the trace shown in FIG. 3 in accordance with an embodiment of the invention;
FIG. 9 shows a graph of the correlation coefficient between an actual trace and the reconstructed trace, as a function of the number of features chosen, for three applications in accordance with an embodiment of the invention;
FIG. 10 shows a graph of a first feature in accordance with an embodiment of the invention;
FIG. 11 shows a graph of a second feature in accordance with an embodiment of the invention;
FIG. 12 shows a graph of a third feature in accordance with an embodiment of the invention;
FIG. 13 shows a graph of the first component in several applications in accordance with an embodiment of the invention;
FIG. 14 shows a graph of the second component in several applications in accordance with an embodiment of the invention;
FIG. 15 shows a graph of the third component in several applications in accordance with an embodiment of the invention;
FIG. 16 shows a graph of an application that is to be detrended in accordance with an embodiment of the invention;
FIG. 17 shows a graph of one feature of a detrended application in accordance with an embodiment of the invention;
FIG. 18 shows a graph of a second feature of a detrended application in accordance with an embodiment of the invention;
FIG. 19 shows a graph of a third feature of a detrended application in accordance with an embodiment of the invention;
FIG. 20 shows of a graph of an application trace in accordance with an embodiment of the invention;
FIG. 21 shows a graph of a synthetic generated trace of the application trace shown in FIG. 20 in accordance with an embodiment of the invention;
FIG. 22 shows a flowchart in accordance with an embodiment of the invention; and
FIG. 23 shows a block diagram of a computational system in accordance with an embodiment of the invention.
NOTATION AND NOMENCLATURE
Certain term(s) are used throughout the following description and claims to refer to particular system components. As one skilled in the art will appreciate, different companies/industries may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.
DETAILED DESCRIPTION
The following discussion is directed to various embodiments of the invention. Although one or more of these embodiments may be preferred, the embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. In addition, one skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to intimate that the scope of the disclosure, including the claims, is limited to that embodiment.
In a single system there may be hundreds or thousands of applications running simultaneously. If one had to analyze each application at a time, it would be a rather exhaustive task. Furthermore, the whole system's performance is affected not only by the behavior of each single application, but also by the resulting execution of several different applications combined together. This means that the system's overall performance is given by the superposition of several time-series that, in some instances, are not independent. A wide range of important problems require analysis of the entire system, including resource assignment, queuing networks and system behavior analysis. Since a single application analysis is itself a complex task, modeling the whole system behavior is even more difficult. The reason is that, considering each application as a time-series, forms a high dimensional structure.
In accordance with various embodiments of the invention, methods and apparatuses are described that provide for computational analysis including computational utilization analysis and reporting. The computational analysis can be performed on a single stand-alone computer or a computer system having one or more computers coupled directly or indirectly via a computer network. In order to characterize the workload of applications in a shared utility computing environment, Principal Component Analysis (PCA) is applied to a central process unit (CPU) utilization dataset. This dataset can be extracted from a server or other computational device. A workload model which is also referred to as a utilization workload model is generated using a small number of features that are derived from classification of applications based on some of their predominant feature(s).
In other embodiments of the invention, computational analysis, includes but is not limited to, classifying applications based on one or more features, detrending applications by removing one or more features or features from computer traces in order to focus on specific trends caused by one or more features, characterizing application workloads and generating synthetic workloads in order to analyze the effect of a new application. The computational analysis is also not limited to CPU utilization, but can also be applied to any computer hardware/software data, such as memory usage, disk usage, device input/output and network bandwidth data to name a few.
Central to issues regarding capacity analysis/planning is the understanding and prediction of resource usage characteristics or behaviors of the applications being executed in a computational system. For example, applications that exhibit “spiky” CPU usage may require higher CPU utilization allocation to meet a defined service level objective (SLO) given the applications' unpredictable nature, as compared to more predictable applications that have stable usage patterns.
In one embodiment, PCA along with other analysis techniques such as structural analysis are applied to an application dataset (includes data from one or more applications) from a computational system such as a server. Based on this analysis, it is possible to generate a workload model that is described by a small set of features that can be further classified by their resemblance to stochastic process characteristics, such as “periodic,” “noisy” or “spiky.” The number of features used for classification of applications can depend on the particular design requirements. The features are then used for several purposes, including classifying applications based on their behavioral features, de-trending application traces, generating a synthetic workload with the ability to add to or suppress any of the features, etc. The application dataset collected can include CPU utilization data, memory usage data, disk usage data, device I/O data, network bandwidth usage data or any computer hardware data that needs to be analyzed.
The input to the analysis includes average CPU utilization by each application program for a predefined interval of time (e.g., 10 minutes, etc.). Each application program's CPU utilization data is referred to as a “trace” and may comprise a time-series including numerous data points for each time interval. The interval of time selected for the analysis can depend on the type of applications and their behavior pattern that operate in a given system. For example, very spiky applications that require a lot of computational capability over a very short period of time may require the use of short time intervals in order to perform a proper analysis.
Some applications running in a computational system share common behaviors over time. For example, several applications can share the same periodic behavior, such as applications that are utilized during business hours. Some applications can present fairly simultaneous short bursts or spikes of high demand typically triggered by special events that occur during certain periods. These observations of system behavior allows for a complex computational system running a number of applications to be governed by a small set of features and therefore be represented by a lower-dimensional representation in accordance with some embodiments of the invention. Features can include correlated periodicity, simultaneous demand spikes, etc.
Singular values account for data variability along corresponding principal components. Extracting these singular values using PCA or another feature selection technique it can be determined which features bring information into a dataset. There are some components that account for low variability and therefore have low representation in the dataset. The minimum number of features needed to closely approximate a high-dimensional structure, is referred to as the intrinsic dimensionality of the data. Using PCA, a large amount of data can be processed quickly to determine whether the whole system has low intrinsic dimensionality, and to identify the prominent features exhibited in the data. PCA is a useful technique for feature selection. A large amount of data can be processed quickly to determine whether a system has low intrinsic dimensionality using PCA. PCA also helps identify the prominent features exhibited in the data, thus making it possible, by exploiting common temporal patterns shared by applications, to generate a workload model that is described by a small set of features.
In a computational system such as a Hewlett Packard RP8400 production server using HP-UX™ operating system and an HP Open View Performance Agent™ (OVPA) that is used to collect performance data from the system, the OVPA aggregates the server's CPU utilization at predetermined intervals and writes to a log file which subsequently is extracted and stored. In Table 1 there is shown an illustrative embodiment in which CPU utilization information was collected for the above system over a two-week period. During the two-week collection period, CPU utilization percentages were collected during 5-minute intervals. Table 1 shows the maximum, the average and the standard deviation of the percentage of CPU utilization during the two-week period. The number in the first column is used as a further reference to the applications. From Table 1, it is possible to conclude that the server is still under light utilization.
TABLE 1
Num.
Application
Max
Avg
Std. Dev.
01
ARC
14.31
0.08
0.04
02
B2B
24.79
9.59
5.64
03
Contivo
0.34
0.02
0.01
04
Esgui
0.38
0.22
0.03
05
Parallax
0.11
0.04
0.01
06
Primavision
3.14
0.19
0.25
07
Psghrms
9.49
1.08
1.21
08
Pshd
5.12
0.54
0.63
09
Psportal
18.56
0.97
1.65
10
Rdma
0.09
0.00
0.01
11
Rocket
0.60
0.01
0.02
12
Wwtb
10.37
0.01
0.01
From the data collected, a CPU utilization measurement is generated. This measurement can take the form of an “m×p” matrix X, where the number of rows, m, represent the number of time intervals (e.g., number of 5-minute intervals during a two-week period) and the number of columns, p, are the number of applications (e.g., p=12) in the system (note that m>>p.)
Each column “i” of the matrix represents an application time-series, referenced by a vector X i , and each row represents an instance of all the applications at time t. The matrix X is used as an input for PCA. FIGS. 1-3 show some examples of application load traces. The plot shows the percentage of CPU utilization as a function of time. FIG. 1 shows the utilization for application 2 , FIG. 2 shows the utilization for application 6 and FIG. 3 shows the utilization for application 7 from Table 1. The application traces shown in FIGS. 1-3 show some temporal patterns during the course of the two week study period.
PCA can place data into a new set of components or coordinates with the property that the first or principal component points to the maximum data variation magnitude, in terms of a Euclidean norm. After the first component is found, the second orthogonal component is found by removing the information captured by the first component and capturing the maximum variation of the residual, and so forth. This is illustrated graphically using a two-dimensional space. In FIG. 4 there is a group of data being fitted to a principal component along the direction that captures the maximum variation in magnitude from the data. This is equivalent to finding the eigen-vectors of X T X, X T =Xv i =λ i v i where i=1, . . . , p. The eigen-values, λ i , provide the magnitude of the variation along each component i. Because X T X is symmetric and positive definite, its eigen values are non-negative. The eigen-vectors, λ i , are vectors of size p and they form the transformation matrix V. To maintain consistency, the vectors, v i , are rearranged according to their corresponding λ i values in decreasing order.
In the new mapped space, the contribution of principal component i is given by u i =Xv i . The u i vector of size m is actually a feature shared by all applications along the principal component i. It can be normalized to unit length by dividing by the singular value σ i =√{square root over (λ i )}. Since the V matrix is sorted in a way in which the first component represents the maximum variation in energy, u 1 is the most dominant feature, u 2 is the second most dominant feature, etc.
Conversely, the original data can be reconstructed from features as:
X=U ( V −1 ). (1)
where U is the m×p feature matrix and V is a p×p matrix containing the eigen-vectors.
In accordance with an embodiment of the invention, in order to examine the low intrinsic dimensionality of the application set presented in the above example, PCA is applied to the dataset. The singular values account for the data variability along their correspondent principal components. Extracting the singular values using PCA, it can be determined how many features actually bring information to the dataset. In other words, some components account for low variability and therefore have low degrees of representation in the dataset.
There are two possible causes for the low intrinsic dimensionality. First, if the magnitude of the loads differs greatly among the applications, the ones that have the greatest mean values will dominate the energy (or variance) in the dataset. Second, the other cause of low intrinsic dimensionality can be attributed to the common patterns among the time series, making the dimensions correlated and, therefore, redundant.
To avoid the first effect discussed above, the time series data is normalized to zero mean and unit variance as follows:
X
i
,
t
=
X
i
,
t
-
X
_
i
,
*
σ
i
.
(
2
)
A scree plot as shown in FIG. 5 can be used to carry out the dimensionality analysis. In the plot, the singular values are plotted against their magnitude. As shown in the example of FIG. 5 , while features 1 and 2 account for a change of two points in magnitude, the other ten features together account only for one. If for example the first three attributes are considered to reconstruct the original trace, it is possible that the reconstruction will preserve the main characteristics of the original, even though the process will incur some loss or distortion.
Referring now to FIGS. 6-8 , there is shown the reconstructed traces of applications presented in FIGS. 1-3 , using only three out of twelve features. As shown in FIGS. 6-8 , the temporal patterns of the applications shown in FIGS. 1-3 are preserved respectively in FIGS. 6-8 . The number of features that are selected to generate the reconstructed traces depends on the error tolerance level that can be tolerated for the particular system being evaluated.
Correlation between a reconstructed trace and original trace can be plotted in order to determine which features have the greatest impact on the correlation coefficient. An illustrative plot of features selected for the reconstructed trace of different applications versus correlation coefficient is shown in FIG. 9 . In the example shown in FIG. 9 , the first feature has a significant effect on the correlation while features two and three further add to the correlation. Since three features were able to capture the temporal characteristics of the original traces, in the example of FIG. 9 three is considered the intrinsic dimensionality of the data. In other examples, the number of features that are considered the intrinsic dimensionality will depend on the particular system characteristics.
The three most dominant features are displayed in FIGS. 10-12 . The first feature shown in FIG. 10 has a periodic trend having a period of a complete business day (e.g., 288 intervals of five minutes). Given the periodic nature of this feature, the feature is referred to as “periodic.” The longer valleys show in FIG. 10 is attributed to weekends, when the activity drops.
In FIG. 11 , there is shown the second feature, which in this case resembles noise such as Gaussian noise, so the feature is referred to as “noisy.” The third feature is shown in FIG. 12 . The feature displays spikes in each business day, with some intensification during the second week due to increased application use activity. Given the regular peaks of activity, this third feature is referred to as “spiky.”
Referring now to FIG. 22 , there is shown a flow chart highlighting some of the actions taken when performing capacity management in accordance with one embodiment of the invention. In 2202 , trace data that had been collected is cleaned and normalized in 2204 . At 2206 , a more fundamental representation of the data is found. For example, PCA may be applied to the data in 2206 in order to simplify the representation of the data. In 2208 , a model can then be built using the feature descriptions. Some of the uses of the utilization workload model can include classifying applications based on feature strengths presented on traces as in 2210 . The model of 2208 can also be used to generate a synthetic application workload based on amplification or suppression of certain features in the model as in 2212 . Some of these different uses for the utilization workload model of 2208 are discussed in more detail further below. Finally, in 2214 an automatic report is generated. This report can take many forms depending on the particular requirements for the information. For example, the report can show how each of the applications operating in a system would be classified for a period of time (e.g., periodic, spiky, noisy or a combination of some of these). Also, graphical representations of the application over time can also be shown, so a system operator can get a quick look at the temporal behavior of the applications.
In FIG. 23 there is shown a block diagram of a computational device such as a server 2300 . A central processing unit (CPU) 2302 provides the overall control for server 2300 . A hard drive 2306 stores programs such as the capacity management program of the present invention which are executed by CPU 2302 . Memory 2304 such as random access memory (RAM), etc and an input/output (I/O) interface 2308 are also coupled to CPU 2302 . The I/O interface 2308 has coupled to it a display 2310 , keyboard 2312 and a printer 2314 . The display 2310 and printer 2314 can be used to display to an operator the capacity management reports generated in accordance with embodiments of the invention.
The extracted features in accordance with embodiments of the invention can be used to describe a system's behavior, classify the applications in a system and analyze the applications components, and generate synthetic traces for test and simulation purposes. Although specific uses are discussed below, the extracted features can be used for other uses associated with capacity management.
Classifying Applications
Large numbers of applications can be classified quickly using just a few features using the classification technique of the present invention. By classifying the applications using the features, a computer system planner can distribute applications among computational resources (e.g., servers) in order to better balance out the resources and provide for better system performance.
The features help collect the pattern of variation over time common to the set of original traces. The extent to which a particular pattern is presented on each application trace is given by the entries of V i , the eigen-vectors. The graphs for the entries of the three dominant components are shown in FIGS. 13-15 . The numbers in the x-axis correspond to the number of the application operating in the system. The greater the absolute number of the entry as shown by the y-axis, the stronger the corresponding feature is present in the original application load behavior. As an illustrative example, the third component in FIG. 15 which corresponds to the third or “spiky” feature, application number 6 has a very strong presence of this feature in its behavior. Application 6 is shown in FIG. 2 . The strong spiky nature of the application can be confirmed by looking at the plot of the original trace. In the same fashion, applications 2 and 7 have the strongest presence of the periodic behavior, as shown in FIG. 13 .
Using the above classification technique, applications can be classified according to one or more of their predominant features: periodic, noisy or spiky. In order to determine which traces belong to a particular class, traces are selected if their entry in the component is greater than the mean value of the absolute values of all entries. Using this criterion, all applications in the first component greater than 0.27 are considered periodic, those applications having entries greater than 0.26 in the second component are considered noisy, and the applications greater than 0.20 in the third component are considered spiky. In practice all traces do not have to be classified. Finding one or more of the predominant behaviors of the traces helps make important capacity planning decisions. The results of the classification are shown in Table 2 below.
TABLE 2 Num. App f1 f2 f3 Class 1 ARC 0.30 0.09 0.24 Periodic, Spiky 2 B2B 0.37 −0.18 0.08 Periodic 3 Contivo 0.27 0.38 0.19 Noisy 4 Esgui 0.28 −0.16 −0.06 Periodic 5 Parallax 0.29 −0.21 0.36 Periodic, Spiky 6 Primavision 0.14 0.18 −0.78 Spiky 7 Psghrms 0.39 −0.26 −0.15 Periodic 8 Pshd 0.37 −0.24 −0.31 Periodic, Spiky 9 .Psportal 0.23 −0.34 0.05 Noisy 10 Rdma 0.22 0.51 −0.05 Noisy 11 Rocket 0.23 0.21 −0.03 Noisy 12 Wwtbl 0.28 0.40 0.17 Periodic, Noisy
The above classification helps to quickly understand the predominant behavior of a particular trace. It should be noted that the criteria used to attribute traces into classes can be modified based on particular design requirements.
Detrending Applications
Resource assignment is a useful technique for capacity planning. This method takes advantage of the seasonal complementarities of the periodic behavior of the traces and exploits any negative correlations between different applications' demand in a shared resource environment. It also considers the effect of unusual events, such as unexpected peaks. This capacity planning technique can also benefit from the structural analysis. It is possible to “detrend” application traces to examine one effect at a time. For example if one is interested in determining the seasonal behavior of the applications, the periodic behavior would be of most interest. Thus, the original application traces annulling the noisy and spiky components can be reconstructed. This will reconstruct a trace governed only by its periodic trend and, therefore, the analysis could be carried out more precisely. Sometimes, in analyzing the original trace directly it is difficult to distinguish and isolate only the effect of the periodicity.
Detrending includes removing one or more characteristics from a trace such as described above in order to concentrate on one or more effects at a time. For example, if a system operator is interested in determining when computer usage spikes occur, the operator may want to remove or “detrend” out of a computer utilization trace any “noise” features so that a better picture of the “spiky” computer usage behavior can be analyzed. The number of features such as “noisy” and “periodic” that are removed when performing the detrending can depend on such things as the number of features that are used to classify the traces as well as the differences between the features.
Analyzing the periodic trend alone, one can complement the valley of a period with a peak from another. For example, applications being utilized by users physically located on the East and West coasts, running in the same system, could differ in terms of utilization as a function of the hours of the day and therefore the load periodicity could be complemented in order to maximize resource utilization. On the other hand, to study anomalies and unexpected events in the system, one could be interested in separating the invisible spikes from the other effects. This can be done by considering only the third component in the reconstruction.
As an illustration an actual application shown in FIG. 16 is detrended, presenting each effect, period, noise and spike, separately in FIGS. 17-19 . It is interesting to see the intensity of the noise as shown in FIG. 18 and, also, the spikes shown in FIG. 19 , which were indistinguishable when looking at the original trace shown in FIG. 16 .
Generating Synthetic Workload
Synthetic workloads are useful for testing and simulation purposes in order to evaluate the effect of a new, slightly different application. As an example, one may want to simulate the behavior of a new application which is coupled to a headlines news database. This new application has the same noisy behavior as an existing one, lets say application y. However, due to a special unexpected event (e.g., news event), there is a peak during the business hours of some days. To evaluate the impact of this new application in the system, a synthetic trace from the y model is generated, intensifying the peak effect of application y. Doing so, the performance implications of the new application in the system due to the effect of “bursty” conditions incurred by the special news event can be evaluated. Similarly, it is also possible to suppress or undermine the presence of a feature in an application trace in order to reproduce some desirable behavior. The reconstruction of an original trace can be accomplished by:
U ( V −1 ) i =X i r . (3)
The synthetic trace generation is basically a reconstruction with a new combination of the basic features, that is, playing with the values of the inverted matrix V −1 . Equivalently, the equation mentioned previously can be written as:
U [ v 1 v 2 v 3 ] = X i r . ( 4 )
where v 1 is the parameter related to the periodic component, and v 2 and v 3 are related to the noisy and spiky components, respectively. As an illustration, application 2 has the following configuration:
U [ 0.37 - 0.18 0.08 ] = X 2 r ( 5 )
If one wanted to reproduce the behavior of application 2 for example, but with half of the amplitude induced by the periodic feature. In order to produce this result, only half of the value in entry v 1 is attributed, that is v 1 =0.18. The resulting trace can be seen in FIGS. 20 and 21 . These figures compare the reconstruction of application 2 shown in FIG. 20 , using the original configuration, to the new synthetic generated application shown in FIG. 21 that mimics its behavior but presents half of the periodic amplitude.
Outputs generated by the capacity planning method and apparatus in accordance with some embodiments of the invention include:
1) The principal feature(s) of one or more applications operating within a computational system. The features can be displayed graphically, or in tables, or in other formats for interpretation. Some features that can be provided include “periodic” which can include those applications exhibiting periodic cycles, “noisy” for applications that do not exhibit specific patterns or random patterns, and “spiky” for applications that exhibit occasional higher-than-normal peaks or valleys. Other feature characterizations can be provided depending on the particular capacity planning requirements. Different computational systems may have different feature sets that can provide for better interpretation. 2) The coefficient of each feature in an application trace can be provided. The coefficient of each feature representing the strength of the feature in a particular application trace. 3) A reconstructed trace for each application using a number one or more of the features, with the number of features selected to reconstruct a trace being selectable by a system operator. 4) The correlation of an original trace and a reconstructed trace for each application. The reconstructed trace being generated using a number of the features in an application trace. The correlation coefficient forming a number between 0 and 1 that represents the “goodness-of-fit” or resemblance of the reconstructed trace to the original. The number of features used for the reconstructed trace can be increased or decreased in order to achieve the correlation to the original trace desired. 5) Each application can be labeled based on the strength or weakness of each particular feature. If a particular feature reaches or exceeds a threshold, the feature may for example be characterized as prominent or weak. As an illustrative example, application A can be labeled predominantly feature 1 , while feature 1 can be “Periodic.” 6) A synthetic trace can be generated based on an existing application. A synthetic trace includes a reconstructed trace with one or more features amplified or suppressed. Synthetic traces are useful in analyzing traces using a controlled feature to see how they behave.
Although a few outputs have been discussed above, other outputs can be generated. Outputs can for example be outputted to a reporting system such as a web-based performance monitoring system, stand alone computer or integrated into a data collection system.
By extracting a small set of features common to the traces of all applications, the trace data can be processed fairly simultaneously, this allows for quick characterization of application behavior on resource consumption (e.g., CPU utilization). The method and apparatus described allows for the characterization of a system as a whole and does not require calibration or estimation of pre-defined parameters. A system operator can characterize the behavior of applications by representing the application traces using a small number of features that makes the classification easier to accomplish.
Using the classification, synthetic traces can be generated that allows an operator to simulate the behavior pattern of a new application and perform what-if scenarios on existing applications. The classification also helps system operators when they can add or remove computing resources from a computational system.
The above discussion is meant to be illustrative of the principles and various embodiments of the present invention. Numerous variations and modifications will become apparent to those skilled in the art. It is intended that the following claims be interpreted to embrace all such variations and modifications. | A method for computational analysis includes collecting an application dataset and extracting one or more features from the application dataset in order to generate a utilization workload model. The features correspond to an intrinsic dimensionality of the dataset. An apparatus and a computer-usable medium storing instructions executable by a processor for providing the computational analysis is also described. | 6 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a process for cospinning synthetic trilobal filaments differing in modification ratios. More particularly, the filaments are cospun from trilobal spinneret orifices of different configurations.
2. Description of the Prior Art
Synthetic filaments having trilobal cross-sections and particular benefits associated therewith are described, for example, in U.S. Pat. No. 2,939,201. A characteristic of such filaments is their cross-section modification ratio, or MR. Certain benefits can be obtained from mixtures of such filaments or fibers having different modification ratios as described, for example, in U.S. Pat. No. 3,220,173. A convenient method of preparing such filament mixtures is to co-spin the different types in the desired ratio and to process the combined filaments through subsequent steps such as drawing, crimping, cutting into staple, etc. as a single mixed-filament product.
When filaments of two different modification ratios are co-spun using two differently dimensioned sets of known capillaries such as those with three intersecting slots with each having parallel sides, random fluctuations in process variables such as spinning temperature cause MR changes along and among filaments. Process adjustments to maintain an acceptable difference in MR between the two filament species is quite difficult.
An object of this invention is to reduce the sensitivity to normal spinning process fluctuations of changes in the difference in modification ratios among filaments cospun from a common polymer supply through at least two spinning capillaries designed to yield different filament modification ratios and where one of the modification ratios is greater than 1.9.
SUMMARY OF THE INVENTION
The invention is an improvement in a process for cospinning at least two synthetic trilobal filaments from the same polymer melt wherein one filament has a modification ratio no greater than 1.9, the other filament has a modification ratio greater than 1.9, and the two filaments differ in their modification ratios by at least 0.3 and preferably by at least 0.6 MR units. The improvement comprises spinning the filament of lower modification ratio through a spinneret capillary configured as three radially intersecting tapered slots and spinning the filament of higher modification ratio through a spinneret capillary configured as three radially intersecting reverse-tapered slots.
Preferably the tapered and reverse-tapered slots are tapered to define an angle of from about 3° to about 15° between intersecting imaginary lines which are extensions of the sides of a given slot.
DESCRIPTION OF THE DRAWINGS
FIG. 1 represents the magnified transverse cross-section of a spinneret capillary comprised of three radially intersecting tapered slots.
FIG. 2 represents the magnified transverse cross-section of a spinneret capillary comprised of three radially intersecting reverse-tapered slots.
In FIG. 1, symmetrical capillary 20 consists of three radially intersecting slots 22 whose imaginary center lines 23 intersect at center point 24. Each slot 22 has the same length 25 measured between center point 24 and flat tip 28 which is perpendicular to center line 23. Each slot 22 is tapered such that the base width 26 is greater than the width of tip 28 to define a taper angle B between imaginary extensions 29 of the sides of slot 22. Angle C between adjacent slots 22 is shown equal in each instance (120°).
In FIG. 2, symmetrical capillary 30 consists of three radially intersecting slots 32 whose imaginary center lines 33 intersect at center point 34. Each slot 32 has the same length 35 measured between center point 34 and flat tip 37 which is perpendicular to center line 33. Each slot 32 is reverse-tapered such that the base width 36 is less than width 38 of tip 37 to define a taper angle D between imaginary extensions 39 of the sides of slot 32. Angle E between adjacent slots 32 is shown equal in each instance (120°).
Although the capillaries of the Figures are shown to be symmetrical in each instance, symmetry is not a requirement of this invention provided the specific shape conditions are met. For example, lengths 25 or 35 and angles C or E may differ among slots in the same capillary. The slot tips of all three capillary types may be squared, rounded, expanded, or otherwise modified as known in the art without changing their relative performances as described herein.
DESCRIPTION OF THE INVENTION
Spinneret capillaries for spinning trilobal filaments configured as three radially intersecting slots which radiate from a common point are well-known. The modification ratios of filaments spun from such capillaries are affected not only by configuration and size of the capillary but also by spinning conditions such as polymer relative viscosity, spinning temperature, and quenching conditions used for solidifying the freshly spun filaments. When using a common polymer supply and identical spinning and quenching conditions (i.e., when cospinning) to produce filaments having a desired constant difference in modification ratios, such fluctuations in processing conditions can have a highly undesirable effect upon the modification ratio differential. This invention facilitates maintenance of a fixed differential in modification ratio between filaments under such normal fluctuating conditions when one filament has a modification ratio greater than 1.9.
The process of this invention is particularly useful for cospinning filaments in the manufacture of crimped staple fibers for use in carpet yarn wherein the filaments of one group have a modification ratio within the range of 1.6 to 1.9 and the filaments of another group have a modification ratio within the range of 2.2 to 2.5.
The modification ratio of filaments spun through tapered trilobal capillaries as in FIG. 1 is relatively insensitive to changes in spinning conditions. Unfortunately, the highest modification ratio practicably obtainable with such capillaries is only about 1.9. Therefore, the tapered slot configuration is not suitable for the high MR filaments of this invention which have an MR in excess of 1.9 (preferably 2.2 to 2.5).
"Modification ratio" (MR) as used herein is defined as the ratio of the radius of a circle which circumscribes the filament cross-section to the radius of the largest circle which can be inscribed within the filament cross-section. For filament cross-sections having substantially equal lobes, these circles are concentric as described in Holland U.S. Pat. No. 2,939,201.
The MR of each filament type is determined on the as-spun filaments prior to any cold-drawing step by measuring 10 filaments of each particular filament type and calculating the average. In actual practice, the measurements are made on photographic enlargements of carefully microtomed cross-sections of undrawn yarn. Considering method error, a constant MR is assumed when none of the individual measurements differ from the average by more than ± 0.15 MR units.
"Relative viscosity" (RV) is the ratio of absolute viscosities at 25° C of a polymer solution to its solvent. In the Examples, the solvent is formic acid/water (90/10 parts by weight) and the solution is prepared by dissolving 5.5 gm. of dried polymer in 50 ml. (25° C) of the solvent. As employed herein, the "polymer" is always a sampling of freshly extruded filaments.
The term "cospinning", as used herein, applies not only to spinning two types of filaments through different capillaries in the same spinneret, but also to spinning through at least two spinnerets of the same spinning machine where all capillaries of each spinneret are identical but differ from spinneret to spinneret. In any case, the filaments of both types are spun from a common polymer supply under substantially identical spinning conditions and are combined to provide a mixed filament or fiber product.
Polymers useful in the process of this invention are any of those conventionally melt spun. Polyamides are preferred, including polyhexamethylene adipamide (66 nylon), polycaproamide (6 nylon), and their copolymers. Polyesters (e.g., polyethylene terephthalate), copolyesters, and polyalkylene polymers (e.g, polypropylene and its copolymers) are also advantageously employed.
In the following examples filaments are extruded from a supply of poly(hexamethylene adipamide) containing 0.02% by weight TiO 2 delusterant as very fine dispersed particles. A screw-melter converts the flake polymer to polymer melt. Relative viscosity of the melt is varied as desired by controlling temperature and relative humidity of recirculating inert gas in a conditioner through which flake passes before being melted. Nominal RV of the extruded polymer is about 66, but, as specified hereinafter, RV is varied over a range of 60 to 72 to test the effect of RV on MR. Unless otherwise specified, extrusion temperature of the melt is 290 ± 2° C.
Filaments in each example are produced at a single position fitted with a spinneret plate having 332 extrusion capillaries arranged in 8 parallel rows in staggered array such that each odd-numbered row has 42 and each even-numbered row 41 capillaries. All capillaries in odd-numbered rows are identical with a given trilobal cross-section, and all capillaries in even-numbered rows are identical with a different trilobal cross-section. Exact cross-sections are specified hereinafter. The polymer melt is spun to filaments at the rate of 110 lb./hr. (49.9 kg./hr.), and the filaments are quenched in a chimney using cross-flow air at 45 ± 3° F. (7.2 ± 7° C) and quench-air flow rates of from 290 to 380 ft. 3 /min. (8.21 to 10.76 m. 3 /min.), as subsequently specified. The quenched filament bundle is then collected as a tow which, in a separate operation, is drawn at a draw-ratio of 3.75X and crimped conventionally in a stuffer-box crimper. All filaments so prepared are nominally of 18 dpf (20 dtex).
EXAMPLE I
This Example utilizes a spinneret plate having only the tapered insensitive capillaries of FIG. 1 and consequently is not of the invention.
The odd-numbered rows in the spinneret plate (producing the low-MR species) have capillaries characterized by: slot length 25 is 14.0 mils (0.36 mm.), base width 26 is 7.0 mils (0.18 mm.), width of flat tip 28 is 4.3 mils (0.11 mm.), taper angle B is 12.8°, and symmetrical slot angle C is 120°. Capillary length is 4.0 mils (0.10 mm.).
The even-numbered rows (producing the high-MR species) have capillaries characterized by: slot length 25 is 17 mils (0.43 mm.), base width 26 is 7.6 mils (0.19 mm.), width of flat tip 28 is 4.8 mils (0.12 mm.), taper angle B is 3.25°, and symmetrical slot angle C is 120°. Capillary length is 8.0 mils (0.20 mm.).
Measured filament modification ratios under the shown spinning conditions are:
______________________________________Low MR Values -Quench-air flow Yarn RV MRft. .sup.3 /min. m..sup.3 /min. 60±3 66±3 72±3 Change______________________________________290 8.21 1.65 1.70 1.75 0.10320 9.06 1.70 1.65 1.75 0.10350 9.91 1.70 1.70 1.80 0.10380 10.76 1.65 1.80 1.80 0.15 MR Change 0.05 0.15 0.05High MR Values -Quench-air flow Yarn RV MRft. .sup.3 /min. m..sup.3 /min. 60±3 66±3 72±3 Change______________________________________290 8.21 1.75 1.80 1.85 0.10320 9.06 1.80 1.80 1.90 0.10350 9.91 1.75 1.85 1.85 0.10380 10.76 1.80 1.90 1.95 0.15 MR Change 0.05 0.10 0.10______________________________________
These results show that the MR from each set of capillaries is relatively insensitive to process variables and the differential between sets remains relatively constant; however, the desired differential of 0.3 between sets was not obtained in spite of the differences in capillary dimensions.
EXAMPLE II
This example shows cospinning two species differing in MR by at least 0.3 MR units and having a high MR in excess of 1.9 and a low MR less than 1.9. The odd-numbered rows of the spinneret plate (producing the low-MR component) have tapered capillaries (FIG. 1) identical to those of the odd-numbered rows in Example I. The even-numbered rows (producing the high-MR component) have reverse-tapered capillaries as shown in FIG. 2 and characterized by: slot length 35 is 18.3 mils (0.46 mm.), base width 36 is 5.7 mils (0.14 mm.), flat tip width 38 is 7.6 mils (0.19 mm.), reverse taper angle D is 6.5°, and symmetrical slot angle E is 120°. Capillary length is 8.0 mils (0.20 mm.).
Modification ratios obtained with changes in quench air flow and RV are:
______________________________________Low MR Values -Quench-air flow Yarn RV MRft..sup.3 /min. m..sup.3 /min. 60±3 66±3 72±3 Change______________________________________290 8.21 1.65 1.70 1.70 0.05320 9.06 1.60 1.65 1.75 0.15350 9.91 1.65 1.75 1.70 0.10380 10.76 1.70 1.70 1.75 0.05 MR Change 0.10 0.10 0.05High MR Values -Quench-air flow Yarn RV MRft. .sup.3 /min. m..sup.3 /min. 60±3 66±3 72±3 Change______________________________________290 8.21 2.35 2.40 2.55 0.20320 9.06 2.30 2.35 2.55 0.25350 9.91 2.40 2.45 2.60 0.20380 10.76 2.45 2.55 2.65 0.20 MR Change 0.15 0.20 0.10______________________________________
Modification ratios obtained with changes in quench air flow and extrusion temperature are:
______________________________________Low MR Component (RV 66±3)MR Values -Quench-air flow Extrusion Temperature MRft. .sup.3 /min. m..sup.3 /min. 287° C 291° C 295° C Change______________________________________290 8.21 1.65 1.70 1.75 0.10380 10.76 1.70 1.75 1.80 0.10 MR Change 0.05 0.05 0.05High MR Component (RV 66±3)MR Values -Quench-air flow Extrusion Temperature MRft. .sup.3 /min. m..sup.3 /min. 287° C 291° C 295° C Change______________________________________290 8.21 2.30 2.45 2.55 0.25380 10.76 2.40 2.60 2.65 0.25 MR Change 0.10 0.15 0.10______________________________________
Comparison of the MR changes for this high-MR component with those of this low-MR component reveals that the reverse-tapered high MR capillary of FIG. 2 is only slightly more sensitive to process variables, than is the tapered capillary of FIG. 1. The ranges of RV and quench air-flow investigated in the example are broader than any variations normally anticipated in a given commercial production process. Thus, using the tapered capillary of FIG. 1 for a low-MR component cospun with a high-MR component utilizing the reverse-tapered capillary of FIG. 2 yields a MR differential which is constant within the normal accuracy of detection of shifts in MR which affect product quality. | The ability to maintain a constant differential between modification ratios of trilobal filaments under cospinning conditions is provided by spinning a filament of lower modification ratio through a spinneret orifice consisting of three radially intersecting tapered slots and a filament of a higher modification ratio through a spinneret orifice configured as three radially intersecting reverse-tapered slots. The orifices configured as three radially reverse-tapered slots provide a high modification ratio with low sensitivity to normal spinning process fluctuations which in combination with orifices having tapered slots for filaments of lower modification ratio facilitate maintenance of a more constant differential in modification ratios between the filaments. | 3 |
The present invention is directed toward a wood fire starter and more specifically toward a wax-based wood fire starter brick having improved characteristics.
BACKGROUND OF THE INVENTION
Fireplace fires can be difficult to start. Unless one is skillful and has access to well-seasoned wood, dry kindling, wadded newspaper and a chimney with a good draft, much time and effort will be wasted trying to get a fire started. All too often, at least one of these requirements is lacking. These problems led to the development of wood fire starters such as STARTERLOGG brand fire starters which are manufactured by the assignee of the present invention. Wood fire starters are made primarily from a mixture of wax and sawdust and can be lighted easily with a match and can burn for 15 to 45 minutes, depending on the size and quality of the product. These products burn evenly and intensely, are sized to rest on a fireplace grate, and make it possible to light a fireplace fire without newspaper or kindling or when the wood is slightly damp. They allow almost anyone to start a fire successfully.
Wood fire starters are generally brick-shaped, but almost any shape can be used. These products are often sold stacked one atop another in multiple-unit packages. A problem which often arises when the product is packaged in this manner is that the individual fire starters, being made largely of wax, tend to stick together. Because the products are rectangular, and the side and end walls of the product are evenly aligned, they can be very difficult to separate when partially stuck together. This problem is aggravated when the fire starters are stored in close proximity to a heat source such as a fireplace or wood stove or when unused fire starters are stored over the summer in hot weather. Even moderate temperatures can cause some degree of sticking.
These melted-together fire starters can be separated and used, but only with some difficulty. Sometimes, they can be broken by hand, but often a knife or screwdriver must be inserted between the bricks to separate them. Besides being inconvenient, attempts to separate the bricks may end up breaking the bricks themselves into pieces too small to sit on a fireplace grate. Separating the bricks in this manner can also create many small flakes or crumbs of wax and sawdust which are a further nuisance.
This problem can be overcome by individually wrapping each brick or by inserting papers between the bricks, but this solution increases the cost of the product and slows production. Alternatively, bricks can be chemically treated to render them less sticky or they can be dusted with talc or other substances to reduce sticking, but these actions increase cost and adversely affect the lighting and burning characteristics of the product. It is therefore desirable to provide an improved wood fire starter which can be made and packaged in a standard manner, but which is also easy to separate from the other fire starters in the package.
SUMMARY OF THE INVENTION
These and other problems are overcome by the present invention which comprises a wood fire starter shaped so as to reduce the contact area between adjacent, stacked fire starters. A first embodiment of the invention comprises a brick having a generally octagonal cross-section. This cross-section allows the fire starters to be stacked such that the area of the contact region between the bricks is less than the width of the brick. Generally, bricks having a cross-section with five or more sides comprise part of the present invention. However, the octagonal cross-section is preferred over these other shapes as it allows the fire starter to maintain a generally brick-shaped appearance and does not adversely affect the extrusion process by which these products are normally manufactured. Stacked octagonal bricks can also efficiently fill a substantial volume of a standard rectangular package. The bricks may also be provided with generally rectangular end portions to increase the stability of the bricks when stacked. The use of a flattened end portion in this manner creates a generally I-shaped region of contact between the bricks which provides stability while still allowing the bricks to be easily separated. A second embodiment of the invention comprises a generally rectangular brick having convex top and bottom walls. When stacked, these convex walls contact one another only along a narrow strip and thus are easy to separate even when slightly melted together. A third preferred embodiment uses a brick having concave upper and lower walls which contact one another only along the outer edges thereof when stacked. A fourth preferred embodiment of the invention comprises bricks having a trapezoidal cross-section with one of the parallel walls being shorter than the other, wherein the parallel walls form the top and bottom walls of the bricks when stacked. A fifth embodiment of the subject invention comprises bricks having a hexagonal cross-section.
It is therefore the principal object of the present invention to provide a wax-based brick which can be stacked and easily separated from a stack.
It is another object of the present invention to provide a wax-based brick shaped to provide gaps between the brick and adjacent bricks when stacked.
It is a further object of the present invention to provide a wax-based brick which can be stacked and cleanly separated from a stack.
It is still another object of the present invention to provide a compact package of wax-based fire starters which can be easily separated from one another.
It is still a further object of the present invention to provide a wax-based fire starter brick which can be stacked with less contact between bricks than occurs when rectangular bricks are stacked.
It is yet another object of the present invention to provide a generally rectangular package of non-rectangular wax-based fire starters.
It is yet another object of the present invention to provide a wax-based fire starter brick which can be stacked to substantially fill a rectangular volume while minimizing the are of contact between the bricks.
It is a further object of the present invention to provide a stable stack of wax based bricks having a reduced region of contact between the bricks and recesses between adjacent bricks allowing one to easily grasp and then separate adjacent bricks.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects of the present invention will be better appreciated from a reading and understanding of the detailed description of the invention together with the following drawings of which:
FIG. 1 is a side elevational view of a prior art stack of firestarter bricks;
FIG. 2 is a side elevational view of a stack of firestarter bricks according to the present invention;
FIG. 3 is a front elevational view, partly in section, of the stack of bricks shown in FIG. 2;
FIG. 4 is a perspective view of an individual brick taken from the stack shown in FIGS. 2 and 3;
FIG. 5 is a cross-sectional view taken through line 5--5 in FIG. 4;
FIG. 6 is a cross-sectional view taken through line 6--6 in FIG. 4;
FIG. 7 is an end elevational view, partially in section, of a stack of firestarter bricks according to a second embodiment of the subject invention;
FIG. 8 is an end elevational view, partly in section, of a stack of firestarter bricks according to a third embodiment of the subject invention;
FIG. 9 is an end elevational view of a stack of firestarter bricks according to a fourth embodiment of the subject invention;
FIG. 10 is an end elevational view, partly in section, of a stack of firestarter bricks according to a fifth embodiment of the subject invention; and,
FIG. 11 is a perspective view of a firestarter log according to the subject invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, where the showings are for purposes of illustrating preferred embodiments of the subject invention only, and not for limiting same, FIG. 1 shows a stack 8 of prior art fire starter bricks 9. These prior art bricks are rectangular solids and have parallel and planar top walls 10 and bottom walls 11 extending between parallel and planar side walls 12. When stacked as shown in FIG. 1, there is no space between the bricks 9 and the bricks tend to stick to one another when stored. Such bricks are all of the same size and are stacked squarely atop one another which makes them difficult to separate without the use of a knife or without breaking the bricks into unusably small fragments.
FIGS. 2 and 3 show a stack 14 of fire starter bricks 16 according to a first embodiment of the present invention and FIGS. 4 and 11 show one of these bricks separated from the stack. Each brick preferably has a length of about 7 inches, a width of about 21/2 inches and a height of about 1 inch. As can be seen from these figures, the bricks 16 are generally octagonal which results in the creation of gaps 18 between the bricks when stacked. As best seen in FIG. 4, the bricks 16 each include front and rear end walls 22, a left side wall 26 and a right side wall 28, and a top wall 30 comprising a first sloped portion 32, a central portion 34, a second sloped portion 36 and flattened end portions 37 extending about 1/4 inch inwardly of each of the end walls 22. The bottom wall 38 of the brick 16 is identical to the top wall 30 and includes a first sloped portion 40, a central portion 42, a second sloped portion 44 and flattened end portions 45 adjacent each of the end walls 22. The top wall central portions 34 are about 1/2 inch wide (or about 1/4 of the overall brick width) and are generally horizontal when the bricks are stacked and are parallel to the bottom wall central portions 42. The side walls 26 and 28 are about 7/8 inch high and are generally vertical and parallel to one another. The top wall sloped portions 32 and 36 are about 7/8 inch wide slope away from the top wall central portion 34 in the direction of the bottom wall 38 at an angle of about 2 to 10 degrees from the horizontal. A slope of about 4 degrees is preferred. The bottom wall sloped portions 40 and 44 slope away from the bottom wall central portion 42 toward the top wall at a similar angle.
To form a stack 14 from the bricks 16, a first brick 16 is placed with the bottom wall central portion 42 on a horizontal surface and a second brick 16 is placed such that the bottom wall central portion 42 thereof rests on the top wall central portion 34 of the first brick and so that the flattened end portions 45 of the bottom wall rest on the flattened end portions 37 of the top wall. The region of contact R1 between the bricks in this embodiment is therefore generally I-shaped and defined by the flattened end portions 37 and central top wall portions 34 of the lower brick and the flattened end wall portions 45 and bottom wall central portion 42 of the upper brick. Significantly this region of contact is approximately 41/2 square inches instead of the 171/2 square inch, rectangular, region of contact which results when prior art bricks are stacked. And because the contact occurs only near the ends of the bricks and along a narrow central strip between the end portions, it is easy to obtain leverage along the sides of the bricks to break adjacent bricks apart. Stacking the bricks in this manner also produces the gaps or channels 18 therebetween which makes the bricks easier to separate, even when they have slightly melted. The gaps or channels 18 are about 1/8 inch wide and extend along the sides of the bricks between the flattened end portions 37. The channels are also preferably about 7/8 inch deep and defined by the second sloped top wall portion 36 of a lower brick and the second sloped bottom wall portion 44 of an upper brick. These gaps reduce sticking as described above and provide an opening into which a user's finger tips can be placed to obtain leverage to pry the bricks apart. The octagonal shape makes the bricks 16 easy to separate from the stack but does not affect their manufacturing cost or burning characteristics.
The bricks 16 are formed by an extrusion process and are cut to length as they pass through a die (not shown). The brick ends are formed into flattened end portions 37 and 45 in the cutting process. Thus, the bricks 16 have a rectangular cross-section through the flattened end portions 37 and 45 as shown in FIG. 5 and an octagonal cross-section between these portions as shown in FIG. 6. These rectangular end portions provide greater stability to the stack 14 and also provide a solid appearance to the stack 14 when viewed end-on.
FIG. 7 shows a stack 46 of bricks 48 according to a second embodiment of the present invention. The bricks 48 each have front and rear end walls 50, a left side wall 54, a right side wall 56, a convex top wall 58 having flattened end portions 59 and a convex bottom wall 60 having flattened end portions 61. Walls 58 and 60 are smoothly radiused and bow away from one another between the side walls 54 and 56. When these bricks 48 are stacked, the bottom wall 60 of an upper brick 48 rests atop the top wall 58 of a lower brick 48 and the flattened end portions 61 of the bottom wall of the top brick rest on the flattened end portions 59 of the top wall of the lower brick. The resulting region of contact R2 between the bricks is generally I-shaped and defined by the flattened end portions of the bricks and the central portions of the top and bottom walls. In addition, the radiused top and bottom walls produce a gap 62 between the side walls of adjacent bricks when stacked. This gap is preferably about 1/8 inch wide or more and a user's finger tips can be inserted therein to overcome any minimal stickiness between the bricks.
FIG. 8 shows a third preferred embodiment of the subject invention which comprises a stack 46' of bricks 48' similar to the bricks 48 of the second embodiment, but which include a concave top wall 58' and concave bottom wall 60' instead of the convex walls of the second preferred embodiment. Bricks 48 also include top wall flattened end portions 59' and bottom wall flattened end portions 61' in the vicinity of end walls 50'. When bricks 48' are stacked, the region of contact R2' between the bricks is comprised of the region near the left side wall 54 and the right side wall 56 and the flattened end portions 59' and 61'. This leaves a central gap 64 about 1/8 inch wide between the bricks. The presence of gaps 64 greatly reduces the amount of sticking which occurs when the bricks are stacked. This embodiment results in a stack of bricks which appears identical to the prior art stacks of bricks as shown in FIG. 1, but by reducing the region of contact between the top and bottom walls of the bricks, the sticking problem is greatly reduced.
FIG. 9 shows a stack 65 of bricks 66 according to a fourth embodiment of the subject invention which bricks 66 have trapezoidal front and rear end walls 68, a left side wall 72, a right side wall 74, a top wall 76 and a bottom wall 78. Importantly, the top wall 76 is narrower than the bottom wall 78, and the side walls converge toward one another in the direction from the bottom wall 78 to the top wall 76. This gives the brick 66 a trapezoidal cross-section taken parallel to the end walls. In this embodiment, the entire area of the top wall 76 of a first brick 66 contacts the bottom wall 78 of a second brick 66 when the bricks 66 are stacked. However, because the bottom wall 78 is wider than the top wall 76 that supports it, a portion 80 of bottom wall 78 overhangs the top wall 76 on each side thereof. This overhang provides a convenient gripping point and allows a brick 66 to be pried off of a brick beneath it in a stack. This configuration allows fire starter bricks to be easily separated while maintaining wider planar upper and lower walls, which could be desirable in some instances and provides stability.
FIG. 10 shows a stack 82 of bricks 84 according to a fifth embodiment of the subject invention. The bricks 84 have front and rear end walls 86, a left side wall 88, a right side wall 90, a top wall 92 having a first sloped portion 94, a top edge 96, a second sloped portion 98, and flattened end portions 100 adjacent the front end rear end walls 86, and a bottom wall 102 having a first sloped portion 104, a bottom edge 106, a second sloped portion 108 and flattened end portions 110 adjacent the front and rear end walls 86. When the bricks are stacked, the bottom wall flattened end portions 110 and the bottom edge 106 of an upper brick rest on the top wall flattened end portions 100 and the top edge 96 of a lower brick. These bricks contact one another over a generally I-shaped region of contact R5 defined by the top and bottom edges 96 and 106 and the top and bottom flattened end portions 100 and 110. The side walls 88 and 90 are generally oriented vertically when the bricks are stacked and the sloped portions 94, 98, 104 and 108 are angled at about 2 to 10 degrees to the horizontal. Therefore, when the bricks are stacked, small gaps 112 result between the side walls 88 and 90 of adjacent bricks which gaps provide a pry point for separating the bricks. On a typical brick, the resulting gap is on the order of 1/8 inch. This gap in combination with the reduced region of contact between the bricks makes the bricks easy to separate.
The subject invention has been described with respect to several preferred embodiments thereof, it being distinctly understood that many obvious modifications can be made to the invention which still fall within the scope of the claims appended hereto. For example, the invention is applicable to any wax-based brick which is packaged in stacks and needs to be easily separated. The bricks could also be changed to produce a brick having a greater or lesser number of sides than the four to eight shown in the above embodiments without exceeding the scope of this invention. All such modifications are includes within the subject invention to the extent that they are included within the following claims: | A wax-based brick such as a wax and sawdust brick for starting fires in fireplaces and the like is shaped to reduce the area of contact between adjacent bricks in a stack to make the bricks easy to separate from the stack even when the wax has slightly melted. The bricks may have a central cross-section which is octagonal, hexagonal, trapezoidal, or generally rectangular with convex or concave upper and lower walls. The end portions of the bricks have generally rectangular cross-sections to facilitate stacking. | 2 |
CROSS-REFERENCE TO A RELATED APPLICATION
This application claims the benefit of U.S. provisional application Ser. No. 60/681,366, filed May 16, 2005, in its entirety, including all figures, tables, and sequences.
FIELD OF THE INVENTION
The invention relates generally to the fields of biology, medicine, pediatrics, and oncology. More particularly, the invention relates to composition and methods for modulating the characteristics of cerebellar cancer cells.
BACKGROUND
Pediatric brain tumors are the third most frequent malignancy of children, and brain tumors are the leading cause of death in children with cancer. Medulloblastoma is the most common pediatric tumor of the cerebellum. These tumors can seed along the neuraxis and metastasize to extraneural tissue. During brain development, embryonic neuroepithelial cells migrate outwards and laterally to form the external granular layer of the cerebellum. Primitive neuroectodermal tumors (PNET), like medulloblastomas and basal cell carcinomas (BCC) of the skin, have been associated with two inherited cancer syndromes: Gorlin's and Turcot's. Gorlin's Syndrome, also called nevoid basal cell carcinoma syndrome (NBCCS), is an autosomal-dominant disease characterized by a range of tumor types such as BCC, medulloblastoma, ovarian fibroma, meningioma, fibrosarcoma, rhabdomyosarcoma and cardiac fibroma. Three percent of patients with Gorlin's develop medulloblastoma and Turcot patients are 92-fold more likely to develop medulloblastoma than the general population.
There is accumulating evidence that medulloblastomas result from the molecular dysregulation of the hedgehog (Hh) pathway, in particular sonic hedgehog (SHh), smoothen (Smo), patched (Ptch) and the transcription factor family, Gli1-3. The hh family of genes and their control in mammalian embryonic development is certainly pivotal. SHh plays a number of significant roles in embryonic development including the development of the cerebellum. SHh is produced by Purkinje cells and by granule neuron progenitor cells and is a mitogenic factor for granule neurons as well as a differentiation factor for Bergmann glial cells. In fact, cerebellum hyperproliferation appears to be the result of increased levels of SHh and its prolonged expression. Indeed, SHh has been shown to be associated with medulloblastomas from studies involving transgenic mice that over express SHh and in a transgenic human tissue model.
It is also known that mutations in ptch are responsible for Gorlin's Syndrome. In these individuals, one copy of the ptch gene is mutated, resulting in many of the heterozygous cases of medulloblastoma. Between 12 and 40% of non-inherited BCC arise from inactivation of both alleles of ptch. Ptch mutations, along with several other members of the Hh signaling pathway, also have been directly implicated in the development of medulloblastomas.
Cubis interruptus (Ci) is the terminal component of the Hh pathway, mediating transcriptional activation of hh target genes in response to Hh. Binding sites for Ci have been identified upstream to the promoters of both wg and ptch. There is a high degree of sequence homology between ci and the vertebrate Gli family of transcription factors. In vertebrates there are three homologs of the ci gene: gli1, gli2 and gli3, each having its own distinct pattern of expression. The Gli proteins are large transcription factors that bind DNA in a sequence specific manner via the last three fingers of their five zinc-finger domain. Gli1 is the most potent activator. Gli2 & 3 are thought to have dual functions both as a modified full-length activator and as a truncated processed repressor. Gli1 is constitutively activated in BCC, NBCCS and medulloblastoma.
Since its discovery in plants, post-transcriptional gene silencing has become an important tool in molecular biology. It was shown early on that gene silencing was mediated through a diffusable trans-acting product and later that this trans-acting factor was double-stranded RNA (dsRNA). Both antisense and sense RNA were able to shut down expression of a target gene. Gene silencing studies have shown that dsRNA are more effective at suppressing target genes than anti-sense or sense-strands alone. Only a few molecules of dsRNA are required to attain complete gene silencing. This dsRNA effect has been termed RNA interference (RNAi). RNAi can also be induced by transfecting cells with plasmids that express siRNAs. Furthermore, plasmids containing a sequence encoding a hairpin-forming, 45-50mer double-stranded RNA molecule termed small hairpin RNA (shRNA) under the control of an RNA Polymerase III (Pol 111) promoter when transfected into mammalian cells, have been shown to be more stably expressed, more efficient at reducing the levels of both exogenous and endogenous gene products and provide longer term reduction in target gene than siRNAs alone.
Many researchers are now using RNAi as a tool to ascertain the function of genes because it allows one to create ‘loss-of-function’ phenotypes quickly and easily. RNAi may also hold promise as a gene-specific therapeutic for the treatment of infectious diseases and cancer.
SUMMARY
The invention relates to the discovery that siRNA-mediated silencing of the shh gene in medullobastoma cells appeared to alter the phenotype, growth rate and growth characteristics of these cells. Accordingly, the invention features compositions and methods of modulating the phenotype of a cerebellar cancer cell by modulating expression of gene encoding a gene product involved in the hedgehog pathway.
Unless otherwise defined, all technical and legal terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All patent applications mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting. Other features and advantages of the invention will be apparent from the following detailed description, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is series of micrographs showing expression of neural markers by tumor cells.
FIG. 2 is a series of histograms and a table showing expression of neural markers by tumor cells.
FIG. 3 is an illustration of the development of probes for a Northern blot analysis.
FIG. 4 is a series of tables showing the determination of the potential 19mer for the synthesis of anti-sense RNA target sequences.
FIG. 5 is a Northern blot analysis of PNET tumor cells treated with different protocols.
FIG. 6 is a flow cytometric analysis of PNET tumor cells treated with different protocols.
FIG. 7 is a Western blot of PNET tumor cells treated with different protocols.
FIG. 8 is a series of photomicrographs of PNET tumor cells treated with different protocols.
BRIEF DESCRIPTION OF THE SEQUENCES
SEQ ID NO:1 shows the nucleotide sequence of the sense strand of Gli1 target sequence #1 (SiRNA #1 (% GC=29 & annealed MW=13240.4)).
SEQ ID NO:2 shows the nucleotide sequence of the antisense strand of Gli1 target sequence #1 (SiRNA #1 (% GC=29 & annealed MW=13240.4)).
SEQ ID NO:3 shows the nucleotide sequence of the sense strand of Gli1 target sequence #2 (SiRNA #2 (% GC=48 & annealed MW=13300.4)).
SEQ ID NO:4 shows the nucleotide sequence of the antisense strand of Gli1 target sequence #2 (SiRNA #2 (% GC=48 & annealed MW=13300.4)).
SEQ ID NO:5 shows the nucleotide sequence of the sense strand of SHh target sequence #1 (SiRNA #1 (% GC=43 & annealed MW=13300.4)).
SEQ ID NO:6 shows the nucleotide sequence of the antisense strand of SHh target sequence #1 (SiRNA #1 (% GC 43 & annealed MW=13300.4)).
SEQ ID NO:7 shows the nucleotide sequence of the sense strand of SHh target sequence #2 (SiRNA#2 (% GC=43 & annealed MW=13300.4)).
SEQ ID NO:8 shows the nucleotide sequence of the antisense strand of SHh target sequence #2 (SiRNA#2 (% GC=43 & annealed MW=13300.4)).
SEQ ID NO:9 shows the nucleotide sequence of the sense strand of ACTB target sequence #1 (SiRNA #1 (% GC=38 & annealed MW=13270.4)).
SEQ ID NO:10 shows the nucleotide sequence of the antisense strand of ACTB target sequence #1 (SiRNA #1 (% GC=38 & annealed MW=13270.4)).
SEQ ID NO:11 shows the nucleotide sequence of the sense strand of ACTB target sequence #2 (SiRNA #1 (% GC=52 & annealed MW=13330.4)).
SEQ ID NO:12 shows the nucleotide sequence of the antisense strand of ACTB target sequence #2 (SiRNA #1 (% GC=52 & annealed MW=13330.4)).
DETAILED DESCRIPTION
Multiple siRNAs complementary to shh, gli-1 were evaluated to determine optimal methods for measuring siRNA-induced gene suppression. Multiple siRNAs complementary to the β-actin gene were used as a control. Two siRNAs were prepared for each target gene. These siRNA were transfected into a medulloblastoma cell line using Ambion's Silencer™ siRNA transfection kit. The effect of in vitro RNAi treatment of medulloblastoma cells on protein expression was measured using flow cytometry and western blot analysis. Alteration of mRNA levels following treatment was assessed using northern blot analysis. The results of these studies show that shh and gli-1 siRNA specifically targeted the mRNA for both shh and gli-1 genes which resulted in a significant decrease (greater than 90% by 96 hours following transfection) in the levels of targeted mRNAs and 85% protein expression as measured by western blot analysis. The loss of protein expression as measured by flow cytometry also showed that there was a significant decrease in the level of protein expression and a reduction in the number of cells expressing the proteins over the 96 hour period. The ability to silence the shh gene using siRNA appeared to alter the phenotype, growth rate and growth characteristics of the tumor cells in vitro. However, despite the silencing of the gli-1 gene, there was no apparent change in cell proliferation, growth characteristics or phenotype of the siRNA-treated tumor cells.
Materials and Methods
PNET cell cultures: Cells were routinely maintained in IMDM supplemented with 10% FBS and 0.6% L-glutamine. Cultures were incubated at 37° C. in T75 cm 2 plastic culture flasks in a humidified atmosphere of 5% CO 2 in air.
Phenotypic analysis of PNET cell cultures: PNET cell cultures were subjected to both flow cytometric analysis and indirect fluorescent antibody assays for the expression of Heat stable antigen (HSA), Vimentin, Synaptophysin, neurofibrillary protein-70 (NFP-70), neurofibrillary protein-250 (NFP-250), Nestin, glutamine synthetase, neuron-specific enolase (NSE) and neuroectodermal antigen (UJ13A), glial fibrillary acidic protein (GFAP) and for S-100. All the antibodies listed above were purchased from Chemcon International (Temecula, Calif.). The antibodies detecting SHh and Glilantigens were purchased from ATCC (Rockville, Md.) and abcam (Cambridge, Mass.) respectively.
Flow cytometry: Cells were labeled as described below (Indirect fluorescent antibody [IFA] assays), placed in sheath fluid and analyzed on a FACSCalibur four-color flow cytometer (Becton Dickinson Immunocytometry Systems, CA) Data analysis was performed by using CellQuest Pro Data Analysing
Software (Becton Dickinson Immunocytometry Systems, CA). The flow cytometer was calibrated prior to each run. Compensation was set up for FITC using single-stained cell populations. All cell analysis was carried out within a low orthogonal light scatter and forward light scatter windows at a rate of more than 2×10 3 cells sec- 1
Indirect fluorescent antibody (IFA) assays: All IFA experiments for the detection of both intracellular and extracellular antigens were conducted using CALTAG labs (Burlingame, Calif.) permeabilization kit. The procedure was as directed by the manufactures instructions. Briefly, for each cell sample to be analyzed an appropriate concentration of primary antibody was added to 1×10 6 cells. The cells were vortexed and incubated for 15 minutes at room temperature. Following this step, 100 ul of the fixing reagent was added and the cells incubated for a further 15 minutes at room temperature. Following incubation, the cells were washed once in 3 ml of phosphate buffered saline (PBS) supplemented with 5% FBS, centrifuged and the wash fluid removed. To the cell pellet, 100 ul of the permeabilization reagent and 10 ul of the FITC-labeled secondary antibody (anti mouse IgG) was added. The cells were vortexed and incubated at room temperature for 20 minutes. Following incubation the cells were washed as previously described above and either examined for fluorescence using UV microscopy or placed in sheath fluid for flow cytometric analysis.
Synthesis of siRNA for gene silencing: In the development of systems to measure gene silencing in mammalian cells, it appears that the most potent siRNAs are those that contain a 19 nucleotide complementary region between both strands (sense and antisense) plus a 2 nucleotide overhang at the 3′ end.
The selection of siRNA target sites on the genes of interest started at the AUG start codon and the transcript scanned downstream for AA di-nucleotide sequences. All the AA di-nucleotide and the 3′ adjacent 19 nucleotides were recorded. All the potential target sites were then compared to an appropriate genome database, such as BLAST for the mouse and human, for the elimination of those sequences that have significant homology to other coding sequences. The resulting target sequences were sent to Ambion, Inc. (Austin, Tex.) and complementary pairs of siRNA oligonucleotides with dTdT or UU 3′ overhangs were synthesized. SiRNA's were synthesized for the genes encoding SHh and Gli1 and also for the reporter gene encoding beta-actin.
mRNA Isolation: PNET cells used for both total RNA and mRNA were grown as previously described. The isolation of and subsequent purification of PolyA mRNA was carried out using Qiagen's Oligotex Direct mRNA Kit (QIAGEN, Calif.) according to manufacturer's instructions.
Plasmid preparation: Cultures of E. coli containing plasmids (pT7pT3) with either Shh or Gli1 inserts were grown overnight at 37° C. in LB broth (with 50 ug/ml of ampicillin) in an orbital shaker. Purified plasmid preparations were prepared using Qiagen's QIAprep Spin Miniprep Kit (Qiagen, Calif.) according to manufacturer's instructions. Plasmid linearization was achieved with NotI (Promega Corporation).
Probe synthesis: Linearized plasmid DNA from the above digests was used to generate T7 RNA polymerase probes by in vitro transcription using Ambion's Strip-EZ™ RNA Kit (Ambion, Austin, Tex.) and following the procedure recommended by the manufacturer (Ambion, Austin, Tex.). Briefly, the reaction was set up in a 1.5 ml microcentrifuge tube at room temperature. The following components were added in order; 12 μl of nuclease-free water, 12 μl of template DNA from restriction digests, 4 μl of 10× Transcription Buffer, 2 μl of ATP Solution, 2 μl of Modified CTP Solution, 2 μl of GTP Solution, 2 μl of UTP Solution and 4 μl of T7 Enzyme Mix. Reactions incubated for 90 minutes at 40° C. After incubation, the DNA template was removed by adding 1 μl of DNase 1 and placing the reaction at 37° C. for 15 minutes. The reactions were stopped with 1 μl of 0.5M EDTA (Gibco BRL®) incubated at 75° C. for five minutes. Probes were then labeled using Ambion's BrightStar™ Psoralen-Biotin Kit. 30 μl of each probe was denatured at 100° C. for 10 minutes. The probes were then quick chilled in an ethanol/ice bath and placed in a 96 well plate that sat on an ice bath. 3 μl of Psoralen-Biotin was mixed with each probe and irradiated for 45 minutes under an ultraviolet 365 nm light. Each probe was diluted in 70 μl of TE Buffer. Non-crosslinked psoralen-biotin was removed by butanol extraction. One extraction/probe was done using 200 μof Water Saturated n-butanol followed by centrifugation and removal of the butanol layer. All probes were then stored at −70° C.
Northern blot analysis: The size and abundance of mRNA was determined by northern blot analysis. All procedures were carried out using Ambion's NorthernMax™-Gly Kit (Ambion, Austin Tex.). Detection of signal was determined using Ambion's BrightStar™ BioDectect™ Kit. Exposure was done for 4-6 hours on Hyperfilm™ ECL (Amersham Biosciences).
Characterization of the siRNA induced gene silencing of target genes: Two target sequences per gene from the 5′, 3′ ends and medial regions were selected based upon the predicted sequence as reported in ‘Ensembl Human Genome Browser’ (GeneView). For transfection, the different populations of PNET tumor cells were grown to between 40-70% confluency in T75 cm 2 tissue culture flasks in normal IMDM growth media. The individual siRNAs, at varying concentrations, including transfection reagent, either siPORT™ Amine (a polyamine) or siPORT™ Lipid (a mixture of cationic and neutral lipids), and Opti-MEM were mixed and incubated together at room temperature for 15-20 minutes. Following incubation, the siRNA mixture was added to the cell cultures and incubated for up to 96 hours. At varying time intervals, the tumor cells were harvested for analysis of both specific mRNA (northern blot) and protein (western blot and flow cytometry). Targeted cells were also examined for alterations in phenotype, growth characteristics and for in vivo tumorogenicity.
Results
Phenotypic analysis of PNET cell cultures: To establish the primitive phenotype and neural origin of the PNET cell line D283 and cell line HM75, prior to gene targeting, indirect fluorescent antibody tagging was carried out using antibodies as described in table 1. To label intracellular antigens for both FACS analysis and IFA, the cells were subjected to a fixation and permeabilization procedure as previously described. Once labeled, the cells were analyzed on either a FACSCalibur four-color flow Cytometer or a UV microscope. The data summarized in Table I and FIGS. 1 & 2 , show that both cell lines have similar phenotype, expressing most of the neural stem cell markers that were examined but do not express either of the neurofilament proteins (NFP-70 NFP-250) or glutamine synthetase (GS). For IFA, antibody-labeled cells were subjected to cyto-centrifugation (200 rpm for 5 minutes), air dried and placed under PBS-buffered glycerol and a coverslip. Cells were then examined using uv light microscopy and the degree of fluorescence determined and recorded as follows: 80%-100%=(4+); 50%-80%=(3+); 20%-50%=(2+); 5%-20%=(1+) and 0%-5%=(−). Also shown is the normal protein expression of both SHh and Gli1 in both the PNET tumor lines. FIGS. 2 a and 2 b give examples of the FACS analysis obtained in such experiments. The data suggest good correlation between the results obtained by indirect fluorescence and the Flow data. The representative data in FIGS. 2 a and 2 b shows that under normal cultural conditions both cell lines express significant amounts of both the SHh and Gli1 proteins. Both cell lines nearly 100% of the cells express these proteins. Interestingly, the tumor line, D283, has a small population of cells that exhibit significantly higher levels of SHh, the significance of which still needs to be determined. Either by flow analysis or by indirect fluorescent labeling, the phenotype of the PNET cell lines can be expressed as shown in Table 2.
Molecular Studies: From the antibody studies mentioned above, it appears that both the PNET cell line D283 and HM75 would be appropriate to use in the in vitro gene silencing studies. Both total RNA and mRNA have been isolated from the respective tumor line and stored at −80° C. However, only mRNA was used in the northern blot analysis.
Synthesis of the probes for Northern blot analysis: The development of the probes used in this study is summarized in FIG. 3 ( a,b,c ). Briefly, A multi-purpose cloning vector (with an ampicillin resistant marker) also containing opposable T3 and T7 promotors that flanked a multiple cloning site were used to clone portions of the human shh and gli1 genes. The genes of interest were cloned into the vector at a NotI and EcoR1 cloning site. Competent bacteria containing the plasmid were grown as colonies on LB agar (containing 50 ug/ml of ampicillin). Individual colonies of bacteria were picked and placed in 5 ml of LB broth (supplemented with 50 ug/ml of ampicillin) and incubated overnight at 37° C. in an orbital shaker. From overnight cultures, plasmid preparations were carried out using Gibco BRL “CONCERT” mini-plasmid-prep system. 1% agarose gels were run to verify the purity of the plasmid preps ( FIG. 3 a ). Restriction enzyme analysis (double digests using Not 1 and EcoR1) was also performed to verify the insert size (data not shown). βactin was the reporter gene that was used as control for the gene silencing experiments.
Northern hybridization was the method used to assay for levels of the target mRNA. RNA probes were chosen over DNA probes because they offer 10-fold better sensitivity and were synthesized by random priming using Strip-EZ RNA Kit. Purified plasmid preps were linearized downstream of the insert with EcoR1. This allowed us to transcribe the antisense RNA probe using the T3 RNA polymerase. Following the removal of the DNA template (linearized plasmid), the RNA probes were purified, concentrated by precipitation and stored at −75° C. ( FIG. 3 b ).
Because the RNA was synthesized using the Strip-EZ RNA Kit, the probes were labeled post synthesis with Psoralen-Biotin. Furthermore, the use of modified CTP in the transcription and synthesis of the antisense RNA probe allows us to degrade and strip the hybridized probe from the northern blots for re-use is subsequent experiments. FIG. 3 c shown below is an example of a test blot at varying concentrations showing both the shh and gli probe activities.
Determination of the gene sequences for the synthesis of the 19mer antisense RNAi's: SiRNAs were constructed for the genes encoding shh and gli1 and β actin. The coding sequences and the transcript sequences were taken from the data given in the Ensembl Human and Murine Gene Bank (The Wellcome Trust, Sanger Institute). In this study, the identification of siRNA target sites were determined as stated in the experimental methods section. Two SiRNA sequences per target were designed for each of the genes under study (see FIGS. 4 a,b and c ), an SiRNA containing a ‘scrambled’ sequence was synthesized to serve as a negative control.
Characterization of the siRNA induced gene silencing of targeted genes: To test the protocol and the synthesized SiRNAs, the Shh and gli1-specific SiRNAs were transfected using siPort™ Lipid. The mRNA was obtained prior to the SiRNA treatment and at 12, 24, 48 and 96 hours following treatment. Northern blot analysis of cells treated with the SiRNAs (see FIG. 5 ) indicated that the level of mRNA specific for either of the targeted genes (Shh and gli1) was significantly reduced within 24 hours and under experimental conditions used in this study was not detectable at 96 hours following SiRNA treatment. Treatment of the cells with either of the shh or gli1 SiRNAs did not effect the level of β actin-specific mRNA ( FIG. 5 ). To assess the effect on protein expression treated cells were examined by IFA (Table 3), western blot analysis and flow cytometry. FIGS. 6 a & 6 b show the loss of protein expression in the PNET cells following the shh-SiRNA treatment. As with the mRNA levels protein expression was reduced significantly and by 96 hours no detectable protein was observed. The western blot analysis ( FIG. 7 ) of the treated cells also shows significant reduction of the protein expression such that in the shh-treated cells protein was barely detectable by 96 hours post treatment. In the gli1-treated cells a reduction in protein expression was observed but there was significantly more gli1 expression by 96 hours when compared to the shh-treated cells. Cells that were treated with the siRNAs were re-plated in 12-well plates and incubated at 37° C. and observed for in vitro growth characteristics. The only significant change in the growth of the cells is shown in FIG. 8 . Under normal cell growth these cells were predominantly non-adherent proliferating in clusters in the supernatant. Following siRNA-treatment the cells were predominantly adherent and had a significantly slower growth rate. This change was more visible in those cells that were treated with the shh siRNA than those treated with gli1-siRNA.
OTHER EMBODIMENTS
While the above description contains many specifics, these should not be construed as limitations on the scope of the invention, but rather as examples of preferred embodiments thereof. Many other variations are possible. Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents. | The hedgehog pathway in cerebellar cancer cells was modulated with siRNA specifically targeted to the shh and gli-I genes. Silencing of the two genes in a medullablastoma cell line transfected with the siRNAs caused significant reduction of mRNA specific for the targeted shh and gli-I genes and a loss of protein expression. The disclosed methods and compositions may be useful for treatment of a range of primitive neuroectodermal tumors (PNET) by shutting down or modulating the expression of gene products associated with the hedgehog pathway. | 0 |
This application is a continuation of Ser. No. 08/216,108, filed Mar. 21, 1994, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thin film transistor (TFT) comprising a thin film of a non-single crystal semiconductor, and to a process for fabricating the same. The thin film transistor according to the present invention can be formed on either an insulator substrate such as a glass substrate or a semiconductor substrate such as a single crystal silicon. In particular, the present invention relates to a thin film transistor fabricated through the steps of crystallization and activation of doped impurities by irradiating a laser beam or an intense light having an intensity equivalent to that of the laser beam. This process is hereinafter referred to as "laser annealing".
2. Prior Art
Recently, active study is made on semiconductor devices of insulated-gate type comprising an insulator substrate having thereon a thin film active layer (which is sometimes referred to as "active region"). In particular, much effort is paid on the study of insulated-gate transistors of thin film type, i.e., the so-called thin film transistors (TFTs). The TFTs can be classified into, for example, amorphous silicon TFTs and crystalline silicon TFTs, according to the material and the state of the semiconductor employed in the TFT. The term "crystalline silicon" refers to non-single crystal silicon, which encompasses all types of crystalline silicon except single crystal silicon.
In general, semiconductors in an amorphous state have a low electric field mobility. Accordingly, they cannot be employed in TFTs used for high speed operation. Furthermore, the electric field mobility of a P-type amorphous silicon is extremely low. This makes the fabrication of a P-channel, TFT (a PMOS TFT) unfeasible. It is therefore difficult to obtain a complementary MOS (CMOS) circuit from such a P-channel TFT, because the implementation of a CMOS circuit requires combining a P-channel TFT with an N-channel TFT (NMOS TFT).
In contrast to the amorphous semiconductors, crystalline semiconductors have higher electric field mobilities, and are therefore suitable for use in TFTs operating in high speed. Crystalline silicon is further advantageous in that a CMOS circuit can be easily fabricated therefrom, because not only an NMOS TFT but also a PMOS TFT is available from crystalline silicon. Furthermore, it is pointed out that further improved characteristics can be obtained by establishing an LDD (lightly doped drain) structure known in the conventional single crystal semiconductor MOS ICs.
An LDD structure can be obtained by the following process steps:
forming island-like semiconductor regions and a gate insulating film;
forming a gate electrode;
introducing impurities at a low concentration to form lightly doped regions by ion implantation or ion doping;
forming masks for the LDD region (by anisotropic etching of the insulating film covering the gate electrode, or by selective oxidation of the anodic oxide covering the gate electrode);
introducing impurities at high concentration by ion implantation or ion doping; and
activating the impurities by laser annealing or thermal annealing.
The most problematic in the above process is the sixth step, in which the amorphous silicon is activated by laser annealing or by thermal annealing. Laser annealing comprises irradiating a laser beam or an intense light having an intensity equivalent to that of a laser beam. However, in general, the laser beam is irradiated from the upper side of the gate electrode. It then results in an insufficiently activated LDD region, because the mask formed in the fourth step functions as a shield.
In contrast to the case using laser annealing, the LDD region can be sufficiently activated by thermal annealing. However, in general, the impurities in the silicon film must be activated by annealing for a long period of time at about 600° C., or by annealing at a high temperature of 1,000° C. or higher. The latter method, i.e., the high temperature annealing can be applied only to cases using quartz substrates, and the use of such expensive substrates considerably increases the production cost. The former process can be applied to a wide variety of substrates. However, the use of inexpensive substrates brings about other problems such as the shrinking of substrates during thermal annealing, because it leads to a low product yield due to the failure upon mask matching. It is therefore necessary to effect the treatments at lower temperatures when such inexpensive substrates are used.
The present invention provides a solution to the aforementioned problems difficult to solve.
SUMMARY OF THE INVENTION
The problems above are overcome by the present invention, which comprises, before laser annealing, exposing the LDD region by partly or wholly removing the anodic oxide formed on the periphery of the gate electrode, and then subjecting the resulting structure to laser annealing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1(A) to 1(E) show schematically drawn step sequential cross section structures obtained in a process according to an embodiment of the present invention (Example 1); and
FIGS. 2(A) to 2(E) show schematically drawn step sequential cross section structures obtained in another process according to another embodiment of the present invention (Example 2).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the process according to the present invention, the anodic oxide need not be removed over the entire portion of the interconnection being formed in the same layer in which the gate electrode is formed. The anodic oxide on at least the part present on the LDD region must be removed. More specifically, only the anodic oxide present on the periphery of the gate electrode formed on the island-like semiconductor region should be removed.
When the anodic oxide is formed not only on the side, but also on the upper surface of the gate electrode and the interconnection formed in the same layer of said gate electrode, the anodic oxide functions importantly as an insulator between the gate electrode and interconnection covered with the anodic oxide, and an interconnection layer formed on the anodic oxide. However, in general, the interconnections are provided as such that they may not cross on the island-like semiconductor region. Accordingly, the anodic oxide on the island-like semiconductor region can be safely removed without impairing the practical electric insulation properties so long as anodic oxide is left on other portions.
The present invention is illustrated in greater detail referring to non-limiting examples below. It should be understood, however, that the present invention is not to be construed as being limited thereto.
EXAMPLE 1
FIG. 1 shows the cross section view of the step sequential structures obtained by a process according to an embodiment of the present invention. Referring to FIG. 1, a 2,000 Å thick silicon oxide film 11 was formed by sputtering as a base film on a Corning #7059 glass substrate 10. Then, an intrinsic (I-type) amorphous silicon film 12 was deposited thereon by plasma CVD to a thickness of from 500 to 1,500 Å, for example, to a thickness of 1,500 Å, and a 200 Å thick silicon oxide film was further deposited thereon by sputtering. The amorphous silicon film was then crystallized by annealing at 600° C. in nitrogen atmosphere for a duration of 48 hours. After annealing, the silicon film was patterned to form an island-like silicon region 12, and a 1,000 Å thick silicon oxide film 13 was deposited thereon by sputtering as a gate insulating film. The sputtering process was performed in an atmosphere containing oxygen and argon at an argon to oxygen ratio of not higher than 0.5, for example, at a ratio of 0.1 or lower, using silicon oxide as the target. The temperature of the substrate during the process was maintained in the range of from 200° to 400° C., for example, at 250° C.
Then, an aluminum film containing from 0.1 to 2% of silicon was deposited by sputtering to a thickness of from 3,000 to 8,000 Å, for example, at a thickness of 6,000 Å. Preferably, the steps of depositing the silicon oxide film and the aluminum film are performed continuously. The resulting aluminum film was patterned to form a gate electrode 14 and an interconnection 15 as shown in FIG. 1(A). Needless to say, the gate electrode 14 and the interconnection 15 are present in the same layer.
Phosphorus was then introduced as an impurity by plasma doping into the silicon region using the gate electrode as a mask. The doping was performed using phosphine (PH 3 ) as the doping gas, and applying an accelerating voltage in the range of from 60 to 90 kV, for example, at 80 kV, to introduce phosphorus at a dose in the range of from 1×10 13 to 8×10 13 cm -2 . Phosphorus in this case was incorporated at a dose of 2×10 13 cm -2 . In this manner, N-type impurity regions 16a and 16b were formed as shown in FIG. 1(B).
The resulting substrate was immersed into an ethylene glycol solution containing tartaric acid at a concentration of from 1 to 5%, and electric current was applied to the gate electrode 14 and the interconnection 15 to allow an anodic oxide (aluminum oxide) layer 17 to grow on the surface thereof. An anodic oxide layer of uniform thickness can be formed stably by electrically connecting the gate electrode 14 and the interconnection 15. The anodic oxide is preferably grown to a thickness of from 1,000 to 5,000 Å, and particularly preferably, in the thickness range of from 2,000 to 3,000 Å. In this case, the anodic oxide layer was formed at a thickness of 2,500 Å.
Then, phosphorus as an impurity was introduced again into the silicon region by plasma doping, using the gate electrode and the peripheral anodic oxide as the mask. The doping was performed using phosphine (PH 3 ) as the doping gas, and applying an accelerating voltage in the range of from 60 to 90 kV, for example, at 80 kV, to introduce phosphorus at a dose in the range of from 1×10 15 to 8×10 15 cm -2 , specifically for example, at a dose of 2×10 15 cm -2 . In this manner, N-type impurity regions 18a and 18b containing the impurity at high concentration were formed. Furthermore, the previously formed LDD region (lightly doped drain region) was partly left over because the anodic oxide functioned as a mask. Thus was obtained a structure as shown in FIG. 1(C).
The anodic oxide formed on the gate electrode 14 was etched thereafter. The anodic oxide formed on the interconnection 15 was left as it was. As a result, a region (inclusive of the LDD region; indicated with an arrow in FIG. 1(D)) was newly exposed. Laser beam was irradiated to the resulting structure to effect laser annealing. The laser used in this case was a KrF excimer laser operating at a wavelength of 248 nm and a pulse width of 20 nsec. However, other lasers, such as a XeF excimer laser operating at a wavelength of 353 nm, a XeCl excimer laser operating at a wavelength of 308 nm, and an ArF excimer laser operating at a wavelength of 193 nm, may be used as well. The laser beam was applied at an energy density of from 200 to 500 mJ/cm 2 , for example, at 250 mJ/cm 2 , and from 2 to 10 shots, for instance, 2 shots, per site. The substrate was heated to a temperature in the range of from 100° to 450° C., for example at 400° C., during the laser irradiation. The impurity was activated in this manner. In this case, in particular, the LDD regions and the boundary between the active region and the LDD region were activated as well. The structure is shown in FIG. 1(D).
Subsequently, a 6,000 Å thick silicon oxide film 19 was formed as an interlayer insulator by plasma CVD, and contact holes were formed therein to establish electrodes with interconnections 20 for the source and the drain regions of the TFT, using a multilayered film comprising metallic materials, such as titanium nitride and aluminum. The resulting structure was annealed at 350° C. for 30 minutes in hydrogen atmosphere under a pressure of 1 atm. Thus was implemented a complete thin film transistor as shown in FIG. 1(E).
EXAMPLE 2
FIG. 2 shows the cross section view of the step sequential structures obtained by a process according to an embodiment of the present invention. Referring to FIG. 2, a 2,000 Å thick silicon oxide film 22 was formed by sputtering as a base film on a Corning #7059 glass substrate 21. Then, an intrinsic (I-type) amorphous silicon film was deposited thereon by plasma CVD to a thickness of from 200 to 1,500 Å, for example, to a thickness of 500 Å, and was patterned to form an island-like silicon region 23. The silicon region was crystallized by laser annealing. The laser used in this case was a KrF excimer laser. The laser beam was applied at an energy density of from 200 to 500 mJ/cm 2 , for example, at 350 mJ/cm 2 , and from 2 to 10 shots, for instance, 2 shots, per site. The substrate was heated to a temperature in the range of from 100° to 450° C., for example at 350° C., during the laser irradiation.
Then, a 1,000 Å thick silicon oxide film 24 was deposited as a gate insulating film by plasma CVD using tetraethoxysilane (TEOS; Si(OC 2 H 5 ) 4 ) and oxygen as the starting materials. Trichloroethylene (C 2 HCl 3 ) was also added into the starting gas material. Oxygen gas was flown into the chamber at a rate of 400 sccm (standard cubic centimeters per minute) before initiating the film deposition, and plasma was generated inside the chamber while maintaining the chamber at a total pressure 5 Pa and the substrate at a temperature of 300° C., and applying an RF power of 150 W. This state was kept for a duration of 10 minutes. Then, silicon oxide film was deposited by introducing oxygen, TEOS, and trichloroethylene into the chamber at a flow rate of 300 sccm, 15 sccm, and 2 sccm, respectively. The substrate temperature, RF power, and the total pressure during the film deposition were maintained at 300° C., 75 W, and 5 Pa, respectively. Upon completion of film deposition, hydrogen gas was introduced into the chamber at such an amount to control the pressure to 100 Torr, to effect hydrogen annealing at 350° C. for 35 minutes.
Subsequently, a tantalum film was deposited by sputtering at a thickness of from 3,000 to 8,000 Å, for example, at a thickness of 6,000 Å. Aluminum, titanium, tungsten, molybdenum, or silicon can be used in the place of tantalum. Preferably, the deposition steps of the silicon oxide film 24 and the tantalum film are performed continuously. The tantalum film was patterned to form a gate electrode 25 for the TFT. Thus was obtained a structure as shown in FIG. 2(A).
Phosphorus as an impurity was implanted into the silicon region thereafter by ion implantation using the gate electrode as the mask. The doping process was performed using phosphine (PH 3 ) as the doping gas and applying an accelerating voltage of 80 kV. Phosphorus in this case was incorporated at a dose of 2×10 13 cm -2 . In this manner, N-type impurity regions 26a and 26b were formed as shown in FIG. 2(B).
The surface of the tantalum interconnection was subjected to anodic oxidation to form an oxide (tantalum oxide) layer 27 on the surface thereof. The anodic oxidation was performed in an ethylene glycol solution containing from 1 to 5% of tartaric acid. Thus was obtained an oxide layer 2,000 Å in thickness. Phosphorus as an impurity was implanted into the silicon region thereafter again by ion implantation using the gate electrode as the mask. The doping process was performed by applying an accelerating voltage of 80 kV. Phosphorus in this case was incorporated at a dose of 2×10 15 cm -2 . In this manner, N-type impurity regions 28a and 28b containing the impurity at high concentration were formed as shown in FIG. 2(C).
Subsequently, the anodic oxide 27 on the gate electrode and the silicon oxide film 24 (except for the silicon oxide film under the gate electrode) were removed, and the impurity was activated by laser annealing. The laser used in this case was a KrF excimer laser operated at a wavelength of 248 nm and a pulse width of 20 nsec. The laser beam was applied at an energy density of from 200 to 500 mJ/cm 2 , for example, at 250 mJ/cm 2 , and from 2 to 10 shots, for instance, 2 shots, per site. The substrate was heated during the laser irradiation to a temperature in the range of from 100° to 450° C., for example at 350° C. Thus was obtained a structure as shown in FIG. 2(D).
Then, a 2,000 Å thick silicon oxide film 29 was formed as an interlayer insulator by plasma CVD using TEOS as the material, and contact holes were formed therein to establish electrodes with interconnections 30a and 30b for the source and the drain regions of the TFT, using a multilayered film comprising metallic materials, such as titanium nitride and aluminum. Thus was implemented a complete thin film transistor as shown in FIG. 2(E).
The thin film transistor thus fabricated was found to yield an electric field mobility in the range of from 70 to 100 cm 2 /Vs at a gate voltage of 10 V, a threshold voltage of from 2.5 to 4.0 V, and a leak current of 10 -13 A or lower upon applying a voltage of -20 V.
The process according to the present invention provides a TFT having an LDD structure. In particular, the present invention advantageously provides an LDD region having a precision in width of about 10 Å. Specifically, the present invention enables precise processing by controlling the voltage of anodic oxidation. More important, the present invention provides an LDD greatly improved in reliability. This is a consequence of, as pointed out previously, performing the laser annealing after exposing the LDD region by removing the anodic oxide which functions as a shield upon laser irradiation. Conclusively, the present invention is greatly contributory to the industry.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof. | A crystalline silicon thin film transistor having an LDD (lightly doped drain) structure and a process for fabricating the same, which comprises establishing an LDD by forming a gate insulating film and a gate electrode on an island-like semiconductor region and implanting thereafter impurities in a self-aligned manner to establish an LDD, anodically oxidizing the gate electrode and introducing impurities to form source and drain regions, partially or wholly removing the anodic oxide from the surface of the island-like semiconductor region to expose the LDD region, and irradiating a laser beam or an intense light having an intensity equivalent to that of the laser beam to activate the impurity region inclusive of the LDD. | 7 |
BACKGROUND
1. Technical Field
The present disclosure relates to imaging systems and, particularly, to a computational imaging system.
2. Description of Related Art
Generally, an image of an object captured by conventional imaging systems is in focus only over a limited object distance range which is known as depth of field (DOF). Therefore, it is difficult to sharply capture object scenes that span large distances. To obtain an extended DOF, one attempt has been made that deliberately blurs an intermediate image captured by an imaging system by placing a coded aperture in the aperture of the imaging system and then digitally removes the blur using reconstruction algorithms. The coded aperture is patterned according to a modulation transfer function (e.g., a delta function). As such, reconstruction algorithms can effectively deconvolute the modulation transfer function and restores the image to a more recognizable likeness of the object with a greater DOF than what that would have been otherwise obtainable. This is known as coded aperture imaging and is one kind of computational imaging system. See Zand, J., “Coded Aperture Imaging in High Energy Astronomy”, NASA Laboratory for High Energy Astrophysics (LHEA) at NASA's GSFC (1996); Levin, A., Fergus, R., Durand, F., Freeman, B., “Image and Depth from a Conventional Camera with a Coded Aperture”, ACM Transactions on Graphics (Proc. SIGGRAPH) (2007); Veeraraghavan, A., Raskar, R., Agrawal, A., Mohan, A., Tumblin, J., “Dappled Photography: Mask Enhanced Cameras for Heterodyned Light Fields and Coded Aperture Refocusing”, ACM Transactions on Graphics (Proc. SIGGRAPH) (2007); and Liang, C. K., Lin, T. H., Wong, B. Y., Liu, C., Chen, H. H., “Programmable Aperture Photography: Multiplexed Light Field Acquisition”, ACM Transactions on Graphics (Proc. SIGGRAPH), Vol. 27, No. 3, Article No. 55 (2008). However, to blur the intermediate image, the coded aperture (e.g., the pattern formed on the coded aperture) also blocks large amounts of light rays incident on the aperture, resulting in large amount of light loss.
Therefore, it is desirable to provide a computational imaging system, which can overcome the abovementioned shortcomings.
BRIEF DESCRIPTION OF THE DRAWINGS
Many aspects of the present computational imaging system should be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present computational imaging system. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
FIG. 1 is a schematic view of a computational imaging system, according to a first exemplary embodiment.
FIG. 2 is a planar view of a liquid crystal (LC) element of the computational imaging system of FIG. 1 .
FIG. 3 is a planar view of the LC element, according to a second embodiment.
FIG. 4 is a planar view of the LC element, according to a third embodiment.
FIG. 5 is a planar view of the LC element, according to a fourth embodiment.
DETAILED DESCRIPTION
Embodiments of the present computational imaging system will now be described in detail with reference to the drawings.
Referring to FIGS. 1 and 2 , a computational imaging system 100 , according to a first embodiment, includes a lens 10 , an image sensor 20 , an LC element 30 , and a digital focus processor 40 .
The lens 10 and the image sensor 20 constitute an imaging sub-system. The LC element 30 functions as the aperture of the imaging sub-system constituted by the lens 10 and the image sensor 20 (placed in the light path of the imaging sub-system).
The LC element 30 is a transmissive LC panel that has a periodically patterned electrode 32 . The electrode 32 is patterned according to a periodical modulation transfer function (i.e., a spatial function):
H ( x,y )=cos 2π( s x x+s y y ), (1)
where an origin of the oxy coordinate system is the center of the LC element 30 , the x axis extends along the widthwise direction of the LC element 30 , the y axis extends along the lengthwise direction of the LC element 30 , s x is a spatial frequency of the electrode 32 along the x axis, and s y is a spatial frequency of the electrode 32 along the y axis. Assuming that: (i) the refractive index of the LC element 30 outside the electrode 32 is n 0 ; and (ii) the refractive index of the LC element 30 at the electrode 32 is n=n 0 +Δn, where Δn is the refractive index variance caused by applying a voltage to the electrode 32 , the refractive index of the entire LC element 30 can be expressed as a refractive index function:
n ( x,y )= n 0 +Δn ×cos 2π( s x x+s y y ). (2)
Also referring to FIG. 2 , in this embodiment, the electrode 32 is a set of concentric annuluses 322 with uniform distances between each two adjacent annuluses 322 . However, the electrode 32 is not limited to this embodiment, but can conform to other configurations, for example, a rectangular spiral line 324 as shown in FIG. 3 , a circular dot array 326 , or a rectangular block array 328 as shown in FIG. 5 .
The digital Focus processor 40 includes a Fourier transforming device 42 , a deconvolution device 44 , an inverse Fourier transforming device 46 , and a refocusing device 48 .
The Fourier transforming device 42 is configured for transforming a space domain amplitude function U I (x,y) of an intermediate image captured by the image sensor 20 into a frequency domain function U ƒ (x,y), where ƒ x , ƒ y are x and y axes variables in the frequency domain, respectively. According to Fourier optics, it can be determined that:
U f ( f x , f y ) = ⅇ [ j 1 2 f ( f x 2 + f y 2 ) ] jλ f · ∫ ∫ - ∞ ∞ U I ( x , y ) ⅇ - j 2 π λ f ( xf x + y f y ) ⅆ x ⅆ y , ( 3 )
where j is the imaginary unit, λ is a wavelength of light rays that captured by the image sensor 20 , ƒ(x,y) is a focal length function of each point (e.g., pixel) (x,y) of the image sensor 20 to bring the corresponding point (x,y) into focus.
In addition, the Fourier transforming device 42 is also used for transforming the spatial function of the electrode 32 H(x,y) into a corresponding frequency domain function: H ƒ (ƒ x ,ƒ y ).
According to complex optics, the function U ƒ (ƒ x ,ƒ y ) is the convolution of a function U S (x,y) and the function H(x,y), that is,
U I ( x,y )= U S ( x,y )· H ( x,y ), (4)
wherein the function U S (x,y) is a spatial domain amplitude function of a real (final) image of objects. As such, to obtain the real image of the objects, the function U ƒ (ƒ x ,ƒ y ) must go through deconvolution to obtain the function H ƒ (ƒ x ,ƒ y ). This is accomplished by the deconvolution device 44 . According to mathematics, it can be determined that:
U ƒ (ƒ x ,ƒ y )= F ( U S ( x,y ))· H ƒ (ƒ x ,ƒ y ), (5)
where F(U S (x,y)) is the Fourier transform of the function U S (x,y). As such, deconvoluting of the function U ƒ (ƒ x ,ƒ y ) can be expressed as:
F ( U S ( x,y ))={ F} −1 ( U ƒ (ƒ x ,ƒ y )) H ƒ (ƒ x ,ƒ y ). (6)
As such, the blur caused by the electrode 32 is digitally removed.
The inverse Fourier transforming device 46 is configured for inversely transforming the frequency domain function F(U S (x,y)) into the spatial domain amplitude function U S (x,y) to restore the real image of the objects.
According to the above, it can be determined that the resulting function U S (x,y) is a function of three variables: x, y, and ƒ(x,y). Therefore, for each point (x,y) of the real image, the unique in-focus focal length ƒ(x,y) can be determined. The refocusing device 50 is configured to determine the unique in-focus focal length for each point (x,y) of the real image to bring all points of the real image into focus. As such, an all-in-focus real image of the objects can be obtained.
By employing the LC element 30 , transmittance of the electrode 32 can be controlled by adjusting the voltage applied thereto. As such, the amount of light loss can be controlled and minimized. Typically, to reduce light loss, a transmittance of the electrode 32 is greater than about 50%.
It will be understood that the above particular embodiments and methods are shown and described by way of illustration only. The principles and the features of the present disclosure may be employed in various and numerous embodiment thereof without departing from the scope of the disclosure as claimed. The above-described embodiments illustrate the scope of the disclosure but do not restrict the scope of the disclosure. | An imaging sub-system, a liquid crystal (LC) element, and a digital focus processor are provided. The LC element is placed in the light path of the imaging sub-system, functioning as the aperture of the imaging sub-system, and includes a periodically patterned electrode which is patterned according to a periodical modulation function and configured to blur an intermediate image captured by the imaging sub-system by applying a controllable voltage thereto. The digital focus processor is configured to deconvolute the periodical modulation function to remove the blur away from the intermediate image and determine an all-in-focus real image. | 7 |
[0001] This invention relates to a modular heating system. In particular to a domestic heating system, or a system of generally small capacity, that has the capability of performing additional functions. It also relates to a mounting arrangement for a vibratory component, especially of a pump or motor in a domestic heating system.
BACKGROUND
[0002] Domestic heating systems generally involve a unit that is euphemistically described as a boiler, and which may be wall mounted or self-standing. It is generally the central unit of the heating system, and the output is generally hot water that is used either indirectly for heating a hot water circuit (for hot water dispensed from taps and showers), usually referred to as DHW, and directly, for space, or central, heating of the building in which the boiler is located, usually referred to as CH. Of course, direct supply of DHW is also possible in “combi” arrangements.
[0003] The source of power for such boilers may be gas or another fuel or another source.
[0004] Increasingly there is a demand for local electricity generation and the economics of such generation are beginning to make sense. WO-A-2003/014534 describes an integrated micro combined heat and power (CHP) system, in which a conventional boiler is provided with a steam circuit that provides heat to an organic rankine cycle (ORC) machine that employs a scroll as the expander, the scroll driving a generator to generate electricity. The present invention relates especially, although not exclusively, to such an arrangement.
[0005] However, there are also other potential capabilities required of a boiler such as provision within the appliance of a thermal store, or of an air conditioning unit, for example. Also, it is desirable to render boilers adaptable.
[0006] WO-A-2010/061190 discloses a boiler unit housed in an enclosure configured to receive a solid state combined heat and power unit or a rankine or stirling engine (CHP device), wherein the boiler unit comprises a heat generating device and a control unit to independently control the heat generating device and the CHP device, wherein the boiler unit is operable without the CHP device being present.
[0007] GB-A-2376271 discloses a similar arrangement.
BRIEF SUMMARY OF THE DISCLOSURE
[0008] In accordance with the present invention there is provided a boiler unit comprising an enclosure including:
a first circuit of a first fluid heat exchange medium, the first circuit having a heating device to heat the first medium, a boost heat exchanger, a valve and a first manifold; a second circuit of a second heating system fluid heat exchange medium, the second circuit having a flow and return port of the boiler unit, a second manifold and said boost heat exchanger for exchange of heat between said first and second heat exchanger media when said valve is open; a space in the enclosure receiving an auxiliary unit to be driven substantially exclusively by said first fluid heat exchange medium and comprising a heat drain; and a boiler control unit to control operation of the heating device according to heat demand of the heating device and otherwise irrespective of the auxiliary unit when connected.
[0013] Said auxiliary unit being “driven substantially exclusively by said first fluid heat exchange medium” means that no additional power beyond any control of the auxiliary unit is employed by the auxiliary unit, which derives its energy required to perform its substantive purpose exclusively from said first fluid heat exchange medium. Thus the present invention employs a single source of heat for both the second circuit, which might conveniently be the domestic hot water and central heating circuit of a residence or building, and the auxiliary unit. This renders control of the appliance relatively very simple, requiring only traditional boiler heating controls with which an existing skilled person (for example a CORGI registered fitter in the United Kingdom) would be familiar.
[0014] Said auxiliary unit may comprise an organic rankine cycle (ORC) unit comprising:
a third fluid heat exchange medium circuit, the circuit including a condenser adapted for connection to said second manifold to provide heat to said second circuit, a pump to circulate said third medium, an evaporator forming said heat drain and adapted for connection to said first manifold to heat said third medium and a rotary expander connected to an electricity generator; and an auxiliary control unit to control the ORC unit and operate said valve.
[0017] In this mode, a boiler incorporating an ORC unit is a micro CHP unit where all the energy delivered (ie heat and electricity) is provided by said heating device. In one arrangement, the heating device is a combustion chamber incorporating a heat exchange coil for transmitting heat from combustion products to said first heat exchange medium. A feature of the present invention can be that the boost heat exchanger is sufficient to transfer substantially all of the heat delivered by the first heat exchange medium to the second heat exchange medium. This means that, when the ORC unit is not connected, there is no loss of heat capacity of the system.
[0018] The auxiliary unit is simply another heat load on the system, so the boiler control is unaffected by its inclusion. Of course, whatever unit is installed has its own control, which does integrate with the first and second circuits to some extent in operating the boost exchanger valve in the first circuit.
[0019] Moreover, when the auxiliary unit, whatever it is, is not connected, the valve is normally open, the auxiliary control unit serving to close the valve so that heat of the first heat exchange fluid can transfer to the third heat exchange medium. Preferably, when the auxiliary unit is an ORC unit and it is connected in the boiler unit, the valve is closed until the ORC unit cannot meet all the heat demand of the second heat exchanger.
[0020] Thus, the system is heat-led. When started, the boiler transfers all heat called for by the second circuit to the first heat exchange fluid and then to the third heat exchange fluid, said valve being closed by the ORC control unit. Indeed, more heat is generated than necessary for the second circuit, the excess being used by the ORC unit to generate electricity. The ORC unit is rated to deliver the anticipated average functioning heat load of the second circuit. This means that during peak load, the ORC unit cannot deliver sufficient heat. In this circumstance, the heat output of the heating device is increased towards its maximum output and at the same time the valve is opened to divert some of the first heat exchange fluid to the boost heat exchanger, so that further heat can be delivered to the third heat exchange fluid.
[0021] Alternatively, said auxiliary unit may comprise a thermal store comprising a tank to include said second heating system fluid heat exchange medium and adapted for connection to said second manifold. Optionally, said tank includes a tank heat exchanger forming said heat drain and adapted for connection to said first manifold and a thermal control unit comprising a thermostat to monitor the temperature of the second medium in the tank and a valve to limit flow of said first heat medium in the tank heat exchanger.
[0022] Alternatively, said auxiliary unit may comprise an absorption driven air conditioning unit comprising a heat pump forming said heat drain and adapted for connection to said first manifold and to be driven by said first heat exchange medium, and a source of refrigerant to be cooled by said heat pump.
[0023] Thus, in accordance with the present invention, a boiler unit can be supplied with or without an auxiliary unit, which can be supplied and fitted subsequently.
[0024] Indeed, in one arrangement, multiple slots or spaces could be provided in the boiler unit to accept multiple auxiliary units, each adapted to be driven by heat from the first circuit. Alternatively, one slot may be adapted to receive an ORC unit as described above and a second slot be adapted to receive an additional heat generation auxiliary unit, such as an ambient source heat pump, or a solar heat source, whereby the energy required to drive the ORC unit may be shared between the additional heat generation auxiliary unit and the first circuit.
[0025] Preferably, said boiler unit comprises a mount for fitment of said auxiliary control unit separate from said space.
[0026] Preferably, said first fluid heat exchange medium is water and steam operating under pressure and being gravity driven. Thus said boost heat exchanger, and the heat drain of said auxiliary unit when present, are above the heating device so that water in the heating device boils and turns to steam which rises to said boost exchanger where the steam condenses and falls back to the heating device as water. The pressure may be in the region of 6 or 7 Bar and the temperature of operation peaking at about 150° C.
[0027] In accordance with an aspect of the present invention there is provided and organic rankine cycle module comprising a control unit and a frame in which frame is mounted:
a third fluid heat exchange medium circuit, the circuit including a condenser adapted for connection to said second manifold to provide heat to said second circuit, a pump to circulate said third medium, an evaporator having ports connection of a source of a first fluid heat exchange medium to heat said third medium and a rotary expander connected to an electricity generator.
[0029] In accordance with a different aspect, there is provided a mounting in a frame for a vibrating unit having a longitudinal axis, the mounting comprising mounts on either side of said longitudinal axis in an axis plane and each mount lying in a mount plane substantially perpendicular said axis plane, wherein at least one mount comprises a pair of brackets, one unit bracket for fixed connection to the unit and the other frame bracket for connection in the frame, each bracket defining mounting faces that lie in bracket planes parallel said mount plane but spaced from one another, resilient blocks disposed between facing mounting faces the unit and frame brackets to support the unit in the frame when connected therein, wherein said mounting faces are inclined with respect to said mount frame and to said axis frame, whereby pairs of said resilient blocks on either side of said axis plane are inclined oppositely with respect to one another.
[0030] Preferably, the mounts are substantially identical on either side of an orthogonal axis plane being orthogonal said axis plane and containing said longitudinal axis, wherein pairs of said resilient blocks on either side of orthogonal said axis plane are inclined oppositely with respect to one another.
[0031] Preferably, there are pairs of said resilient blocks in a said mount on either side of a gravity plane being a plane orthogonal to each of said axis plane and orthogonal axis plane, said gravity plane being arranged to be substantially horizontal when the unit is mounted in the frame, wherein said pairs of said resilient blocks on either side of said gravity plane are parallel inclined.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:
[0033] FIG. 1 is a fluid circuit diagram of a system according to the present invention;
[0034] FIGS. 2 a, b and c are views of a boiler unit incorporating the circuit of FIG. 1 , with various panels removed;
[0035] FIG. 3 is a further view with more panels removed
[0036] FIG. 4 is another view with an ORC unit detached from the boiler unit;
[0037] FIGS. 5 a and b are views of the ORC unit with some frame elements removed;
[0038] FIGS. 6 a, b and c are views of a scroll expander generator arrangement in the ORC unit of FIG. 5 showing the mounting arrangements thereof;
[0039] FIG. 7 is a schematic diagram of an alternative arrangement; And
[0040] FIGS. 8 a and b are schematic diagrams of alternative arrangements in accordance with the present invention.
DETAILED DESCRIPTION
[0041] Referring to FIG. 2 a , an embodiment 10 of a boiler in accordance with the present invention is a wall-mounted unit comprising a housing 12 in the form of a frame 12 a and connected panels 12 b, preferably forming a sealed enclosure when complete (some panels are not shown, including a front cover panel). Preferably, the boiler is gas fired, having a gas supply 14 to a combustion chamber 16 via a gas control vale 18 . A balanced flue 20 , driven by a fan 22 , supplies combustion air to, and exhausts combustion gases from the combustion chamber 16 .
[0042] The combustion chamber includes a primary heat exchanger HX (see FIG. 1 ) in the form of a coiled pipe inside the combustion chamber 16 that has a first heat exchange medium, most conveniently of water, which may be boiled and evaporated by the combustion process.
[0043] Turning to FIG. 1 , the boiler 10 comprises three fluid circuits, a first steam circuit 100 , a second central heating (CH) and/or domestic hot water (DHW) circuit 200 and a third organic rankine cycle (ORC) circuit 300 .
[0044] First circuit 100 comprises pipes 31 a - f , which lead from the heat exchanger HX and complete the circuit through a boost heat exchanger 33 . An expansion vessel E controls pressure in the first circuit. Motive force for the circuit is gravitational, since the steam rises from the combustion chamber 16 and condenses in the boost exchanger 33 which is at the top of the unit. In the embodiment shown, a branch 35 a of steam pipe 31 a leads to an evaporator 49 of an organic rankine cycle unit 50 , described further below. A return branch 35 b reconnects to the water return pipe 31 e. A boost valve 36 controls flow through the boost exchanger 33 . A recuperator 38 warms return water and cools exhaust gases exiting the base of the combustion chamber and exiting through flue root 20 a.
[0045] Second circuit 200 comprises the boost exchanger 33 being supplied with a central heating (CH) and/or domestic hot water (DHW) from return pipe 41 a . This first enters a recuperator 42 where exhaust gases leaving the combustion chamber 16 are finally cooled for exit through flue root 20 a and some initial warmth is given to the return flow in pipe 41 a . After exit from the recuperator, the return flow is in pipe 41 c, which is connected to a condenser 52 in an ORC unit 50 , described further below, assuming that is connected. When the ORC unit is not connected, instead, a bypass pipe 41 b is connected to the exit of the recuperator 42 , which bypass is also connected to the boost heat exchanger 33 . If the ORC unit is present, exit pipe 41 d from the condenser 52 connects instead to the boost heat exchanger 33 . In either case, the circuit is completed by pipe 41 f becoming the flow pipe of the central heating and/or how water system.
[0046] ORC unit 50 is a replaceable module having a frame 54 in which its components are mounted. The third ORC circuit consists of pipes 44 a - f . Pipe 44 a exits a pump 46 that delivers liquid organic heat exchange fluid (of which there are many available, although pentane is a suitable choice) to a regenerator 48 that heats the fluid a first stage. Exit pipe 44 b delivers the warmer fluid to an evaporator 49 which adds further heat and boils the organic fluid under the influence of steam passing through the other side of the evaporator 49 in the steam circuit 100 . The now vaporous organic fluid passes through pipe 44 c to an expander 47 , conveniently in the form of a scroll. The scroll may be connected to a generator 45 . Indeed, the generator and scroll expander 47 may be integrated in a single unit 45 / 47 , as it is in the embodiment illustrated in FIGS. 2 to 6 . Pipe 44 d carries still superheated but nevertheless expanded organic fluid vapour to the regenerator 48 , giving up more heat before passing through pipe 44 e to condenser 52 where its heat is largely given up to the central heating/hot water circuit 200 in condenser 52 .
[0047] Thus the mode of operation and major transport of heat is from the combustion chamber to the steam circuit 100 ; from there to the ORC circuit 300 by exchange in the evaporator 49 ; and from the ORC circuit 300 to the central heating circuit 200 via the condenser 52 . The bridge that circuit 300 represents between the steam circuit 100 and central heating circuit 200 is limited in its heat capacity. It may be limited by any of a number of the different components. The capacity of the circuit needs to be rated at a typical level that provides a) a useful quantity of electricity from the expander/generator 45 / 47 and b) provides most of the heat requirement for the CH/DHW circuit 200 . However, it should not have any greater capacity than that, however, as efficiency is thereby compromised. However, in the event that more heat than the circuit 300 can provide is needed by the CH/DHW circuit, a boiler control unit 70 (discussed further below) opens the valve 36 and permits steam also to enter the boost heat exchanger 33 so that direct connection between the circuits 100 , 200 is achieved, as well as via the bridge circuit 300 . Of course, as discussed above, if the ORC unit is not employed, then the boost heat exchanger is the only link between the steam and CH/DHW circuits 100 , 200 .
[0048] Returning to FIGS. 2 a, b and c , boiler control unit 70 is a typical such unit, controlling the operation of fan 22 and gas valve 18 , as well as sensing various parameters to check for correct operation. It has a typical connection to a central heating system control unit (not shown) that is user operated to control on and off times and provide switching commands, responsive to room and water thermostats etc., to the control 70 . However, when ORC unit 50 is installed, a separate ORC control unit 80 is provided and mounted in isolation unit 90 . Isolation unit 90 is simply a location of the boiler 12 that is isolated from the combustion chamber 16 and ORC unit 50 , whereby the electrical components of the boiler can be protected from the effects of both components. The isolation unit 90 is simply a surrounding wall 92 that divides the space inside the boiler enclosure 12 . Pipes and electrical connections passing through the wall 92 pass through rubber grommets or the like. Control unit 80 controls the pump 46 and also distributes electricity generated by the generator 45 .
[0049] Turning to FIG. 4 , the ORC unit 50 is a separate and separable component that simply plugs into the space 51 provided within the housing 12 . As discussed above, the boiler 10 can be operated without the ORC unit in place. For that purpose, there needs to be connection and break possibilities between the circuits 100 , 200 and the ORC circuit 300 . Thus, pipe 41 c has connection A that is separable, as does pipe 41 d at B. When the ORC is not present. Connections A,B on the boiler side are simply interconnected by pipe 41 b (not shown in FIG. 2 ). Pipes 35 a,b that connect to the evaporator 49 simply use the connections C,D thereto as the beak points. In the event that the ORC is not present, these pipes are simply capped.
[0050] It is to be noted that a micro CHP unit such as disclosed in FIG. 1 has the capacity to function with or without the ORC unit. If it is not connected at all, the valve 36 is permanently open, and the combustion unit 16 can deliver all of its heat to the CH/DWH circuit 200 through the boost heat exchanger 30 which has sufficient capacity itself for this. When the ORC unit 50 is connected, the valve 36 is controlled by the ORC control unit 80 to close, whereby the heat is passed to the ORC unit where a proportion of its energy is converted to electricity. With the system being heat-led, the amount of electricity to be generated, which is generally in the ratio of 10:1 (heat:electricity), is entirely dependent on the heat load demanded by the CH/DHW circuit 200 . However, should the demand reach the maximum capable of being delivered by the condenser 52 , the ORC control unit begins to open the boost valve 36 . This condition can simply be detected by measuring the temperature of the CH flow in pipe 41 f when the ORC unit is fully operational. If this is less than required, then the valve 36 is progressively opened, diverting steam to the boost heat exchanger 33 and supplementing the heating of the CH/DHW circuit 200 from the condenser 52 . For example, the heat capacity of the combustion chamber may be 18 KW. The rating of the ORC unit may be 12 KW, of which 10 KW is supplied to the condenser 52 , 1 KW is lost as conversion losses, and 1 KW is generated as electricity. If, however, the heat demand of the CH/DHW circuit exceptionally exceeds 10 KW, then the valve 36 progressively opens. Thus, if the demand is 13 KW, then the combustion chamber may produce 15 KW, of which 3 KW is added directly at the boost heat exchanger and 10 KW at the condenser with 1 KW of electricity still generated. Also, the ORC control unit 80 is configured to open the valve 36 (or, rather, not prevent it from opening) when an error condition in the ORC unit 50 develops. Such may occur if, for example, the electricity grid faults and there is a requirement for the generation of electricity to cease. In the case of such a situation, the boiler can continue to function. This would have the effect of allowing the evaporator 49 to heat up by the passage of steam through it, with the result that there would be no steam condensation therein because of the lack of flow in the ORC circuit. Consequently, flow of water/steam (which is gravity driven as stated above) would cease in the pipes 35 a,b and the ORC circuit 300 would be taken out of service.
[0051] Turning to FIGS. 6 a,b and c , the expander/generator unit 45 / 47 is mounted in the frame 54 through a resilient mounting arrangement. The expander is subject to periodic vibration caused by opening of each scroll leaf on each rotation. Such vibration cannot easily be avoided and needs damping. Moreover, the nature of the vibrations is not symmetrical.
[0052] Finally, the unit 45 / 47 is relatively heavy and requires vibrational isolation from the remainder of the boiler unit to reduce noise and vibration transmission to the environment.
[0053] Accordingly, a mount 110 (see FIG. 6 c ) comprises first and second brackets 112 , 114 , bracket 112 being essentially parallel a central axis 120 of the unit 45 / 47 , which axis is that passing through the centre of gravity of the unit. A second mount (of two mounts 110 , a,b in
[0054] FIG. 6 a ) is arranged on the opposite side of the unit so that its bracket 112 is also parallel the axis 120 and substantially on the opposite side of it to the other mount. First bracket 114 is preferably that which is connected to the unit 45 / 47 , whereas the second bracket is fixed to the frame 54 . Each bracket 112 , 114 presents four mounting faces 115 , each one disposed to be spaced from a corresponding face 117 on the other bracket and between which a progressive reaction rubber mount 116 can be arranged. The mounting 116 is well known and has a longitudinal 118 axis and a threaded stud 122 at each end that extends from a plate 124 , the rubber 126 being adhered to each plate and extending between the plates 124 .
[0055] Using the x,y,z co-ordinate system, where the z axis contains the axis 120 and the mounts 110 a,b are spaced from each other in the z,y plane, the arrangement is such that the intersections of the axes 118 with the faces 115 of the bracket 114 all lie in a plane parallel the x,z plane. The same is true of the faces 117 of the bracket 112 . However, such planes of intersection of the faces 115 , 117 (in respect of a given mount 110 a,b ) are spaced from each other in the y direction. Moreover, the faces 117 are in pairs on either side of the z,y plane, in a direction parallel the z axis. They are also in pairs on opposite sides of the z,y plane, in a direction parallel the x axis. Finally, the axis 118 of each pair of facing faces 115 , 117 is inclined with respect to all three planes, ie the zy, z,x and x,y planes. Indeed, preferably, they lie along lines parallel the line given by the equation x=y=z or in directions perpendicular thereto.
[0056] The arrangement is such that the unit 45 / 47 is not rigidly mounted in any direction but has freedom of movement, that is to say is reliantly supported, in all directions in the x,y,z space. Thus considering any given orthogonal plane, x,y, x,z or zy, the mounting arrangement permits translational movement in the x, y or z direction, or rotational movement about the x, y or z axis in each plane, each movement leading to compression or extension of the rubber blocks 116 .
[0057] With reference to FIG. 7 , the ORC unit of the previous embodiments is here replaced by a thermal store 250 . Connection A of pipe 41 c of the second CH/DHW circuit 200 is here connected to an inlet of the store 250 and connection B of pipe 41 d is connected to the outlet of the store. Pipes 35 a,b of the steam circuit 100 are connected to the ports C,D of a heat exchanger 252 in the store 250 . If the temperature of the store falls below a set value, a thermal store control unit 80 ′ opens a valve 82 to permit steam to heat the store 250 .
[0058] In FIG. 8 a boiler unit 10 ′ includes the boiler circuits 100 , 200 discussed above and a slot to receive ORC unit 50 , also as discussed above. However, a third “slot” 75 is provided. In this slot is disposed a thermal store unit in the form of a tank 250 ′ which is supplied with connections 76 a,b to the return and flow pipes 41 a,f respectively. Moreover, the exchanger 252 ′ has direct connections 78 a,b to the steam circuit 100 , a valve 79 controlling delivery of heat to the store 250 ′. Of course, if preferred, the heat exchanger 252 ′ could simply be put in series with the condenser, in a diversion of pipe 41 d.
[0059] In FIG. 8 b , the third slot 75 ′ is here occupied by a solar heat generator. A solar panel 260 delivers hot solar heat exchange medium to a heat exchanger 262 which itself is arranged to deliver heat to a modified evaporator 49 ′ that is capable to delivering heat to the ORC medium either from the steam circuit 100 through pipes 35 a,b , as described above, or from the solar medium through extra panel 49 a of the exchanger 49 ′. Alternatively, if the solar medium is hot enough, the heat exchange in exchanger 262 could be with water in branches of the pipes 35 a,b in the water/steam circuit 100 , whereby the exchanger 49 ′ would be as described with reference to FIG. 1 or 8 a .
[0060] Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.
[0061] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
[0062] The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. | A boiler unit comprises an enclosure including: a first circuit of a first fluid heat exchange medium, the first circuit N having a heating device to heat the first medium, a boost heat exchanger, a valve and a first manifold; a second circuit of a second heating system fluid heat exchange medium, the second circuit having a flow and return port of the boiler unit, a second manifold and said boost heat exchanger for exchange of heat between said first and second heat exchanger media when said valve is open; a space in the enclosure receiving an auxiliary unit to be driven substantially exclusively by said first fluid heat exchange medium; and a boiler control unit to control operation of the heating device according to heat demand of the heating device and otherwise irrespective of the auxiliary unit when connected; and an organic rankine cycle (ORC) unit comprising: a third fluid heat exchange medium circuit, the circuit including a condenser adapted for connection to said second manifold to provide heat to said second circuit, a pump to circulate said third medium, an evaporator adapted for connection to said first manifold to heat said third medium and a rotary expander connected to an electricity generator; and an auxiliary control unit to control the ORC unit and operate said valve. | 8 |
This is a division of application Ser. No. 06/860,574 now U.S. Pat. No. 4,769,277, filed May 7, 1986.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention pertains to fibrous substrata for soil-free or hydroponic cultivation.
2. Discussion of the Prior Art
The constantly developing practice of soil-free cultivation has led to the utilization of substrata of various natures, especially vegetable-derived fibrous materials, natural mineral products such as gravels and pozzolanas, or else processed mineral products such as expanded perlites or rock wools.
The choice of substratum depends at once on its characteristics which facilitate cultivation, good solution retention, good aeration, geometric and chemical stability, etc . . . , and economic data such as: cost of the substratum, replacement frequency, as well as the necessary investment, depending on the type of cultivation under consideration, which, can be related to the type of substratum utilized.
Among the processed mineral materials, rock wools present advantageous properties. They offer a very high degree of porosity, of about 95%, good water retention and good aeration. The material is also easy to handle due to its lightness. On the other hand, the cost of these substrata normally leads to multiple uses, for obvious economic reasons. These uses require disinfection, thus handling, which becomes increasingly difficult after successive cultivations because the structure of the material deteriorates. The deterioration of the material also causes a loss of porosity and sinking, which change the cultivation conditions.
Among the advantageous characteristics of the rock wool substrata, the "available" quantity of water retained presents a particular interest.
This characteristic determines the safety margin which is available to maintain the satisfactory moisture conditions. The greater this available water value is for a given volume of material, the greater the degree of safety. If the material presents a large quantity of available water, the feed of liquid to the substratum during cultivation can be effected at less frequent intervals. Still better, the volume of substratum which is necessary for cultivation can be decreased when the available water quantity per unit of volume increases.
The latter characteristic is of great practical interest. A smaller volume of substratum, and more precisely, a smaller amount of fibrous materials, leads to a less costly material. When this decrease in cost is sufficient, it can be accompanied by other advantages, in particular, below a certain threshold, the one-time use of substratum can be envisioned, which allows the elimination of the operations required for the sterilization of the substratum between successive cultivations.
SUMMARY OF THE INVENTION
The purpose of the invention is to provide new mineral fibrous substrata for soil-free cultivation. These mineral materials in accordance with the invention present characteristics such that the amount of available water is appreciably increased.
The inventors have highlighted the existing relations between water availability for fibrous substrata and the structural characteristics of these substrata. The inventors have especially been able to establish the conditions of by-volume mass and fiber fineness which are most satisfactory to produce a good available water reserve.
The substrata according to the invention present a by-volume mass which is under 50 kg/m 3 and preferably under 40 kg/m 3 with fibers whose average diameter is under 8 micrometers and preferably under 6 micrometers.
On an indicative basis, for rock wools which are traditionally utilized as substrata, the by-volume mass is ordinarily higher, and is in the range of 70-80 kg/m 3 or more. The substrata according to the invention are thus quite appreciably lighter than the traditional substrate.
This lightness does not have profound effects on porosity. Indeed, even the conventional substrata offer a high degree of porosity, of about 95%. In other words, in the substratum, the fibers occupy only 5% of the volume, with the rest corresponding to the space which can be occupied by water. Thus, a decrease in the by-volume mass does not substantially increase the available space for the solution. But the decrease in by-volume mass with a decrease in the average diameter of the fibers (and the multiplication of these fibers) seems to promote the development of the capillary actions which can explain the improvement in the substratum's increased water availability.
It must be emphasized that a reduction in the by-volume mass does not always necessarily imply a decrease in the diameter of the useful fibers, i.e., those which participate in the formation of the capillary network which retains water. Especially for rock wools, the production method causes the presence of a relatively significant proportion of "non-fibrous" particles. The term "non-fibrous" indicates particles having a diameter which is much greater than that of the fibers properly speaking, and which is set arbitrarily, for example, at over 40 micrometers. The proportion of non-fibrous materials often reaches, or even exceeds 30% of the total mass of the substratum. As mentioned above, considering the mass of these large particles, they contribute very little to the formation of the capillary network and thus to the solution retention properties. It is thus desirable to utilize products as much as possible which are free of nonfibrous materials, or which have very low contents thereof.
In practice, it is possible during the production process to modify the by-volume mass of fiber felts by compressing them essentially at the time of thermal treatment, which normally establishes their configuration. Thus, substrata are produced, having fibers of the same size, and which differ only by the by-volume mass (and less significantly, the overall porosity) thereof.
For substrata made from larger fibers, namely, those having an average diameter greater than 6 micrometers, it is noted that the available water increases as the by-volume mass increases. This explains why, in the case of rock wools, whose fibers in the most recent techniques and especially those utilized for the production of substrata, have a diameter of about 6 micrometers, the tendency is to implement heavy products.
With finer fibers, for example, 4.5 to 3 micrometers or less, which are also considered in accordance with the invention, the influence of the by-volume mass is much less appreciable. Thus, it is highly advantageous, in addition to what will be seen below with respect to the buckling of the substratum under the weight of the solution, to utilize very light felts having fine fibers.
This difference in behavior, here again, is probably explained by the constitution of a much larger capillary network with fine fibers.
If it appears to be advantageous to reduce the diameter of the fibers comprising the substratum, it is often difficult to pass below a certain limit for various reasons. A first reason is that the production of very fine fibers, for example, those under 1 micrometer, requires techniques at a cost which is unacceptable for cultivation substrata.
Another reason is, for example, that the felts formed from very fine fibers (and having very low by-volume masses) present a small degree of resistance to mechanical stress. They can especially sink under the weight of the solution which is absorbed.
For these reasons, it is advantageous according to the invention to utilize substrata whose fibers are between 1 and 8 micrometers and preferably between 2 and 6 micrometers.
The partial sinking of the saturated material mentioned above does not necessarily constitute an obstacle for use. For the lightest materials, a certain settling during wetting can be envisioned. In this case, it suffices to adjust the dry thickness of the substratum so that, in the damp state, the volume provided for the solution remains sufficient. As such, very light materials, whose by-volume mass can be as low as 15 kg/m 3 can be utilized in a satisfactory manner as substrata according to the invention.
Such products, even reduced, for example, to half of their initial volume under the mass of the solution with which they are saturated, still correspond to very low by-volume masses as compared to that of the conventional substrata.
The buckling which occurs in these materials does not change the cohesion thereof, and is reversible. As soon as the pressure caused by the presence of the solution is relieved, the substratum recovers its volume.
In addition to the advantages of production cost and quality with respect to water retention, the light substrata allow improved packaging and storage. Indeed, it appears that the conventional substrata are relatively rigid products, precisely because of their by-volume mass. They are especially incompressible and cannot be folded or rolled up. Conversely, light fiber felts are known for their good compressibility and further, for their ability to recover their thickness when the pressure is removed. In other terms, the light substrata in accordance with the invention can be compressed, rolled up into a small volume to facilitate the transportation and storage thereof. This capacity increases as the by-volume mass decreases.
Above, we mentioned the great importance of the available water retained by the substrata for the cultivation process was noted. If the capacity for root aeration is also an important factor, in practice, this aeration does not require a substantial fraction of the volume of the substratum to be occupied by air. Indeed, aeration occurs also by means of the oxygen which is dissolved in the nutritive solution, and this aeration is better ensured as the frequency of the replacement of the solution in contact with the roots increases. For this reason, although the substratum plays a role in aeration, the irrigation aspect takes priority.
More so than the quantity of water which is retained by the substratum, it is the available water which is important. Indeed, the water penetrating the substratum is essentially retrained by said substratum. If the water is bound too strongly to the substratum, it can no longer be utilized by the plant. Conversely, the substratum must exert a certain degree of retention, without which the irrigation solution would be immediately drained.
To characterize the retention of the substratum, the water content of samples is determined by subjecting it to pull forces. Thus, for a depression expressed as a function of the logarithm of the height of the water column (in cm), also called pF, the percentage of the volume of the substratum which is occupied by the aqueous phase is defined. Two values for pF are particularly important in characterizing the substratum: a low pF corresponding practically to the conditions of maximum retention and which is arbitrarily established at equal to 1 (or 10 cm on the water column) and a pF equal to 2, which in practice corresponds to the highest degree of pull which can be exerted, for example, by garden plants, and thus constitutes the lower dampness limit above which the substratum must be maintained on a constant basis.
The greater the protection of water extracted between these two pF values, available water, the better the substratum.
Various methods for determining water retention, which can produce slightly different results, have been proposed. The method adopted by the inventors is explained in detail in the examples for embodiment.
Experiments have shown that, for all of the mineral fiber substrata that retention is high at pF1 and very low at pF2, in comparison with the other types of natural or artificial substrata. However, differences can appear among these mineral fibrous substrata, especially for the values at pF1.
The substrata according to the invention have a high degree of retention at pF1 and thus a large available reserve. This available reserve is not under 40% and most frequently is greater than 50%.
For substrata comprised of extremely fine fibers and having very low by-volume masses, the retention capacity is determined using a dampened substratum, to take into account the substratum's propensity to buckle under the weight of the liquid impregnating it.
Due especially to this large quantity of available water, the substrata according to the invention comprised of very fine fibers can be utilized in smaller thicknesses than those traditionally used for rock wool-based substrata.
In practice, rock wool substrata proposed for soil-free cultivation are relatively thick, with said thickness normally exceeding 70 mm. Indeed, it seemed preferable, especially for reasons of durability and cost, but also undoubtedly for reasons related to the methods used in the cultivation process, to utilize relatively voluminous substrata.
Research conducted by the inventors has shown that soil-free cultivation could be effected advantageously on appreciably thinner mineral wool substrata. These substrata have a lower initial cost, which allows the conditions for implementation to be improved, especially through use of fewer cultivations and preferably for a single cultivation. Moreover, each cultivation can be conducted under more constant conditions.
The substrata for soil-free cultivation according to the invention are advantageously comprised of mineral wool felts, the thickness of which is not greater than 40 mm, and preferably is not greater than 30 mm. During tests conducted, it was discovered that such thicknesses, which are much smaller than those previously utilized, are perfectly compatible with good cultivation yields and without stifling growth. Indeed, it appears that the volume of the substratum offered to the plants is sufficient for satisfactory root development, without modifying the surface density of the plants. This volume is also sufficient to maintain a good feed of nutritive solution to the plants.
This small thickness of the substrata compared to prior substrata of the same type also allows for a better control of the nutritive solution which they are saturated. Indeed, solution consumption is practically identical whether a thick or thin substratum is used. The quantity of solution retained is smaller with the thin substratum and, with the supply of new solution relative to the mass of liquid being greater, the composition of the solution which is retained is constantly closer to that of the initial solution.
If it appears advantageous from the economic point of view to utilize thin substrata, in practice, said substrata must nonetheless provide a certain volume for solution retention and root development. Techniques exist in which growing is done without a substratum. In these techniques, the roots grow in the same container in which the nutritive solution circulates on a constant basis. This cultivation method requires a highly specialized installation and large investments. For these reasons, many users prefer cultivation methods in which the substratum is retained.
To maintain a sufficient quantity of solution and provide the roots with the volume necessary for their growth and still, without changing the surface density of the plants, the thickness of the substratum according to the invention is not less than 10 mm.
For most current cultivations, the mineral wool substratum according to the invention has a thickness of about 15 to 30 mm. The thickness which is chosen, in addition to the water retention capacity of the substratum, depends on the plants, the density thereof and the frequency of irrigation which is used. This thickness can possibly also depend on use for more than one cultivation, but, in this case, the use of these substrata does not provide all of the aforementioned advantages. It is specially necessary to envision a sterilization between the successive plantings.
The fibers comprising these felts can be produced from a variety of materials and using various techniques.
Up to the present, only "rock" mineral wools have been utilized to serve as substrata for soil-free cultivation. These rock wools are in fact made from inexpensive materials: basaltic rock, blast furnace cinders and similar materials.
These materials are traditionally processed according to techniques which produce felts containing a high proportion of non-fibrous materials. In use as cultivation substrata, the presence of these non-fibrous materials is of little consequence, but, as we have seen, makes the product heavy without improving the properties thereof. The essential for this production method is that it is relatively economical, which, combined with the low cost of raw materials, allows the production of substrata at prices which are comparable to substrata of different types.
On the whole, these substrata also possess a good level of chemical inertness.
The invention also envisions the use of glass wool felts. These felts, contrary to the former, normally present a great degree of homogeneity due to the method utilized for the production thereof. This pertains essentially to fibers which are formed by passing a melted material through a centrifuge drawing device. The absence of non-fibrous materials normally leads to felts which are much lighter and have similar mechanical resistance properties. In other words, the by-volume mass thereof is normally lower. This allows at least a partial compensation for the fact that their production is generally slightly more costly than that of rock wools.
Production techniques for glass fibers also present the advantage of the ability to produce fibers which are both very fine and very homogeneous, a fineness and homogeneity which cannot be obtained with rock wools.
It is thus possible to produce glass wool substrata having fibers with an average diameter of less than 3 micrometers, and which can be less than or equal to 1 micrometer, as mentioned above.
In the case of the thin substrata according to the invention, the structural properties must be still better ensured, and, as a general rule, glass wool felts present advantageous properties from this point of view, because of the both the fineness of the fibers and the homogeneity thereof.
Moreover, the reduction in the volume of the substratum envisioned according to the invention tends to limit the relative share of the cost of the fibers in the final cost of the product, such that the differences on this point between rock wools and glass wools are less appreciable.
Prior to the invention, the possibility of utilizing glass wool as a cultivation substratum raised objections, especially because of its assumed lack of chemical inertness. Indeed, it was feared that the glass fibers in contact with the nutritive solution would release a large quantity of sodium ions. Cultivation tests conducted with glass wool materials according to the invention have shown that these substrata yielded results fully comparable to those obtained with rock wool cultivation. In fact, a slightly higher sodium ion content is generally noted during the first irrigation. But this content, which is acceptable, subsequently decreases very quickly, settling at values which are similar to those obtained with rock wools. These results are all the more interesting that, due to the use of very fine fibers, exchanges with the solution are greater. For the intended use, the inertness of glass fibers in current use can thus be considered as completely satisfactory.
Quite obviously, the glass compounds chosen do not contain elements which are toxic for plants.
Conversely, it is possible to consider the utilization of fibers which are not systematically inert. Fibers can serve, for example, as a source of trace elements which diffuse slowly in contact with the nutritive solution or can contain phytopathological compounds.
Most often, however, it is preferable to make the fibrous substratum perfectly inert and to reserve the role of supplying the necessary elements for growth to the nutritive solution.
Mineral fiber felts are normally bound using organic bonding materials such as phenolic plastic resins. These resins have no appreciable influence on cultivation at the levels at which they are normally used, namely about 2 to 3% by weight of substratum.
The proportion of bonding material can vary according to the nature of the fibers, thus, for very fine fibers and low by-volume mass felts, the gravimetric proportion of the bonding material can be slightly higher, normally without exceeding 10%.
It must be noted that, if the mineral fibrous substrata are normally derived from products utilized for insulation, the composition of the bonding materials can be appreciably different. Indeed, it is common to add compounds intended to change the properties of the felts to the resin. The composition of the bonding materials can especially include substances which give insulation felts improved resistance to humidity. This pertains, for example, to silicone-based products. Bonding agents which do not contain these hydrophobic products are utilized in the production of the substrata according to the invention.
In addition, even if non-hydrophobic bonding materials are utilized, it is noted that the traditional substrata made of rock wool are very difficult to moisten if they are not impregnated with a certain quantity of an appropriate surface-active agent.
The introduction of the surface-active agent can be done, for example, in the manner which is described in the French Patent Application published under No. 2,589,917.
The surface-active agent is chosen so that it has no harmful effects on cultivation. It can especially pertain to non-ionic agents, such as the product which is marketed under the name of "Dobanol 91-6".
The utilization of very fine fibers according to the invention, by modifying the capillarity of the substratum, can make the use of a surface-active agent unnecessary. This is noted especially with glass wool substrata, whose fibers have an average diameter equal to 4.5 micrometers, but the hydrophilic nature of the fibers changes in a progressive manner. For each degree of hydrophilicity, it is possible to associate a maximum fiber size which allows this degree to be attained.
The substrata according to the invention are also distinguished, if needed, by the manner in which they are implemented. Indeed, if the general process of cultivation is maintained, when the volume of the substratum which is used is decreased, in other words, when the substratum is thin, the conditions for irrigation to meet the requirements of nutritive solution on a constant basis are different.
Generally, the substratum is utilized with either one-cycle or recycled solution irrigation. In the first case, the substratum is fed either by percolation or sub-irrigation, so as to keep the solution content within acceptable limits. The purpose of the essentially discontinuous supply is to compensate losses of solution due to absorption by the plants and evaporation. In the second case, the substratum is fed in a constant manner, and the excess solution which is not retained is recycled after it is supplemented and the content of its various constituents is readjusted.
With the "reserve" of solution offered by the thin substrata being smaller, when the irrigation is discontinuous, the latter is replaced more frequently, but with smaller quantities of solution. This greater frequency, as we mentioned above, allows a better adjustment of the composition of the nutritive solution near the roots.
The modification of the irrigation frequency does not constitute a problem to the extent that this operation is normally conducted in an entirely automatic manner following a pre-established schedule, and the execution of which is ensured by a complex of measurement, dosage and distribution equipment without the intervention of the operator.
The invention is described in detail below, in reference to the drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a schematic cross section view of a cultivation device utilizing substrata according to the invention;
FIG. 2 is a larger scale view of another embodiment for the substrata according to the invention;
FIG. 3 shows the device utilized for water retention measurements;
FIG. 4 is a graphic representation of the distribution of the water - air phases in a substratum according to the invention, as a function of the pull which is exerted.
DETAILED DESCRIPTION OF THE EMBODIMENTS
The plants which are utilized for cultivation can be prepared on soil or on an inert substratum, of the same type which is utilized for cultivation or otherwise. Finally, they are separated from each other with a form 1 which is intended to be placed on the growing substratum 2.
For cultivation, the substratum is placed on a waterproof container 3 which prevents loss of the nutritive solution. The container is normally comprised of an inert, relatively rigid polymer sheet which is held in the form of a trough or box by regularly placed stakes. The latter are not shown in the drawing.
This arrangement is normally supplemented by the presence of a water-proof sheet covering the substratum, with the exception of the areas where the forms are placed, having the function of reducing evaporation of the nutritive solution held in the substratum through contact with the surrounding atmosphere. This sheet is not shown in FIG. 1 for clarity.
The nutritive solution in the method which is shown is distributed by percolation, through capillary tubes 4, directly on the forms 1. The capillary tubes are fed by a distribution conduit 5.
The container 3 can be placed on the base, or, in the traditional manner, on an insulating sheet made, for example, of polystyrene.
The complex can also include heating equipment, located especially directly above the containers.
The nutritive solution can be distributed in a continuous manner, especially when recycling is planned. In this case, the base is placed so that the excess solution which exudes from the substratum can flow and be collected on the side or at an end of the container to be sent to the feed equipment. It can also be distributed in a discontinuous manner, either at predetermined intervals and quantities which are known to provide the appropriate dampness level for the substratum, or as a function of a constant measurement of the dampness rate which allows the feed to be activated when this dampness falls below a certain level.
FIG. 2 shows a mode of embodiment for a substratum according to the invention, in which the mineral fiber felt comprising the substratum is covered with a flexible water-proof sheet 6 to prevent evaporation. The substrata according to the invention can be made with the upper surface of the substratum alone covered with this sheet. Said sheet can also completely surround the felt.
FIG. 3 shows the device utilized to determine the water retention in the substrata for different pF levels.
For said determination, these samples 7 of material comprising the substrata at all 7.5 cm high and are cut into 10 cm side squares.
These samples are immersed completely for 1 hour, then placed on a porous material 8 lining the bottom of a box 9. The porous material, a bed of sand, for example, is initially saturated with water.
The bottom of the box 9 is connected by a flexible conduit 10 to a vessel 11, the level of which is fixed (by an overflow system). The position of the vessel 11 on a vertical support can be adjusted as desired.
The measurement of the depression d is done systematically by referring to the midpoint of the sample. Various levels are successively determined, corresponding to the pFs being studied. The measurements are made after the samples have been maintained up to the obtention of an equilibrium in each new condition of level change.
At equilibrium, the sample is removed, weighed, dried and weighed again after drying. The difference yields the mass of water retained and subsequently the proportion of water and air for each pull condition established.
The retention curves as a function of pF for various materials allow their ability to ensure a good irrigation for cultivation to be compared.
These curves, for mineral fibrous materials, are shaped as shown in FIG. 4. For these curves, the abscissa shows the logarithms for the pulls in water column centimeters; the ordinate shows the percentages of the volume of the substratum occupied by water, air and fiber. The latter, in a constant manner in the example shown, occupies about 5% of the total. These percentages define the areas respectively labeled A, B and C on the diagram.
The differences in percentage between pF1 and pF2 for the portion occupied by water determines the available quantity of water.
For mineral fibrous substrata, pF2 is always very low, with the main differences noted between the various materials for available water thus stemming from pF1. Curves I and II illustrate this type of differences. They correspond respectively to a traditional rock wool-based substratum and a substratum according to the invention, having very fine fibers, for a same by-volume mass. The actual reserve R 2 is appreciably greater in the second case.
The conditions under which the measurements are taken (thickness 7.5 cm of sample) correspond to the traditional substrata. If these conditions allow the products to be compared, they do not reveal the advantages peculiar to the thin substrata proposed according to the invention.
The study of the distribution in the height of the sample in fact shows a very high degree of non-homogeneity. The upper part holds very little water and a great deal of air, and the opposite applies for the lowest part.
Systematic measurements were thus taken for different products according to the invention and others which do not have the accepted characteristics, on a comparative basis. These measurements cover products having different by-volume masses, fiber fineness and thicknesses, but which are made of the same glass and with the same quantity of wetting agent, of about 300 g/m 3 of felt.
The retention measurements at pF1 taken for different fiber diameters, two series of by-volume mass and two thicknesses are as follows:
______________________________________Thickness Diameter micrometersin mm kg/m.sup.3 8 6 4.5______________________________________80-85 80 61 86 9580-85 40 46 57 81.520 40 25 54 86______________________________________
In all cases, these results show an increase in retention for a decrease in the average fiber diameter. This increase becomes greater as the by-volume mass and thickness decrease.
By choosing small thicknesses and a low by-volume mass, a great degree of retention can be obtained when the fibers are sufficiently fine.
The measurements done on a same felt and for different thicknesses evidence a great degree of stability in retention for felts comprised of very fine fibers.
At the different thicknesses studied, the felt comprised of fibers having an average diameter of 4.5 micrometers and of 40 kg/m 3 present the following retentions:
______________________________________thickness (mm): 20 35-40 55-60 80-85retention: 86 85 87 81.5at pF1______________________________________
Taking into account the error inherent in this type of measurement, the differences found are insignificant.
According to the measurements taken, it seems that in the case of felts having high by-volume masses and especially comprised of fibers with larger average diameters, the thickness influences retention, with said retention being appreciably lower than the thickness decreases.
Moreover, it must further be emphasized that only fine fiber felts are suitable for use without a moistening agent.
Taking these results into account, it thus appears totally advantageous to utilize thinner substrata with fine fibers.
Two types of substrata were utilized: the first is comprised mineral wool panels made from blast furnace cinders, the second of glass wool panels.
The respective composition of the fibers in these substrata is as follows:
______________________________________Casting cinder fibers Glass fibers______________________________________SiO.sub.2 42.8% SiO.sub.2 66.9%Al.sub.2 O.sub.3 11.9% Al.sub.2 O.sub.3 3.35%CaO 38.7% Na.sup.2 O 14.7%MgO 3.6% K.sub.2 O 1%Fe.sub.2 O.sub.3 1.2% CaO 7.95% MnO, B.sub.2 O.sub.3 MgO 0.30% 0.4%TiO.sub.2, P.sub.2 O.sub.5 MnO 0.035%SO.sub.3 0.3% Fe.sub.2 O.sub.3 0.49%Misc. 1.1% SO.sub.3 0.26% B.sub.2 O.sub.3 4.9%______________________________________
The substratum panels are bound with a formophenolic resin in a proportion of about 2.5% by weight of the entire product. In the case of rock wools, the substratum also contains about 1% surfaceactive agent.
The panels are cut to the size of 1000×200 and have a thickness of 50 mm for rock wool and 25 mm for glass fiber. The average diameter of the fibers is 5 micrometers for the rock wool (non-fibrous materials not counted and 4 micrometers for the glass wool.
The respective by-volume masses of the rock wool substratum is 40 kg/m 3 that of the glass fiber substratum is only 25 kg/m 3 corresponding to respective porosities of 95 and 98%.
Water retention at pF1 for these substrata is in both cases approximately equal to 70%. Consequently, in both cases, a good water/air equilibrium occurs, which promotes growth.
The growing of Montfavet type tomatoes is effected in a greenhouse according to the methods indicated below.
The sewing is done on 70×75×60 mm blocks of rock wool of the same type as the substratum mentioned above. Placement on the substratum is effected when the first leaves appear.
As a comparison, cultivation is also done on a traditional rock wool substratum, having a thickness of 75mm and a by-volume mass of 70 kg/m 3 with average fiber diameters therein being 6 micrometers.
For the three types of substratum, the growing process is the same. The plants are 30 cm apart in the direction along the length of the substratum, which corresponds to a planting of 2.5 plants per square meter of the cultivating device. The feed illustration is the type described above in relation to FIG. 1.
Irrigation is done with a Coic-Lesaint type solution containing 12.2 milliequivalents per liter of nitric nitrogen, 2.2 milliequivalents per liter of ammonia nitrogen and 2.2 milliequivalents of phosphate. The pH is controlled at around 6.
The plants are fed in a discontinuous manner as a function of the conductivity measurement in the solution contained in the substratum. The feed maintains a conductivity above the threshold corresponding to a content which is not less than 12 milliequivalents of nitrogen per liter.
About 24 weeks pass from the planting until the end of the harvest.
The yield in all cases was about 6.5 kg per foot. Especially, there was no marked difference noted between the cultivation conducted on the thick or thin rock wool substratum. There was also no appreciable difference noted with respect to the yield, between the cultivation on thin rock wool and glass wool substrata.
A better structural tolerance was noted in the glass wool substrata, despite their relatively smaller by-volume mass. This is probably due to the presence of longer fibers, which reinforce the cohesion of the felt.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. | Substrata for soil-free cultivation are characterized by a relatively low by-volume mass. They are also constituted of fine fibers. The substrata present the advantage of a high degree of water retention, even for small thicknesses. | 8 |
FIELD OF THE INVENTION
This invention relates to a bolt-less device for fastening a rail to a tie.
BACKGROUND OF THE INVENTION
According to a known conventional method of fastening a rail to a tie, a single plate spring or a double-folded plate spring is placed on a tie in abutment with the flange of a rail and a spring seat, and then the plate spring is fastened to the tie with a bolt inserted downwardly through a hole in the plate spring. The disadvantage of this conventional method is that the bolt is likely to loosen due to vibrations caused by trains. Moreover, this arrangement permits the rail to be tilted by a transverse force applied to the rail by trains. Since the tilting action cannot be held below prescribed limits, the possibility of a derailment is increased.
OBJECTS OF THE INVENTION
Accordingly, an object of this invention is to eliminate the aforementioned disadvantages of conventional rail fastening devices.
SUMMARY OF THE INVENTION
More specifically, the present invention provides an improved rail fastening device utilizing a spring member having a lower portion terminating in a shaped free end adapted to engage the flange of a rail and an upper portion which tapers toward a free end which engages the topside of the rail flange. An anchor with a shaped hole projects upwardly through the lower portion and rotatably and slidably receives a fastening element having a cam lobe and a detent adapted, when rotated and slid axially into the anchor, to stress the spring member and fasten the rail flange to its underlying tie.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevational view of a rail fastening device constructed according to the present invention;
FIG. 2 is a plan view of the device illustrated in FIG. 1;
FIGS. 3a, 3b and 3c are a front elevational, a plan, and a longitudinal sectional view, respectively, of an anchor used in the present invention;
FIGS. 4a, 4b, 4c and 4d are a front elevational, a plan, a rear elevational as seen from the side of the insertion guiding part, and side elevational views respectively, of a fastening member used in the present invention; and
FIGS. 5a, 5b and 5c are views illustrating certain components of the device in various operative positions, FIG. 5a being a plan view in which the fastening member has been rotated into a fastening position, FIG. 5b being a plan view in which the fastening member has been driven into the hole in the anchor to a locking position, and FIG. 5c being a side elevational view of the fastening member according to the present invention to facilitate understanding of the function of the device.
DESCRIPTION OF PREFERRED EMBODIMENT
Referring now to FIGS. 1 and 2, 1 designates a tie on which a rail 3 is mounted with an insulating elastic pad 2 provided between the rail 3 and the tie 1. On each side of the flange 3a of the rail 3, a spring receiver 6 is placed on the tie 1 in abutment with a transverse pressure receiving protrusion 1a formed in the tie 1. A spring 7 is disposed between the spring seat 6 and the flange 3a and is fastened to the tie 1 by means of a fastening member 5 having a cam section which is inserted in a hole formed in the head of an anchor 4 and turned.
The spring 7 is formed by bending a single plate in a generally oval shape in elevation. The spring 7 has a predetermined length between its free ends 7e and 7c, and the thickness of the upper spring portion 7a of the spring 7 is tapered from a maximum thickness at about the middle of the length of the plate forming the spring 7 toward the free end 7e of the upper spring portion 7a to provide an optimum spring constant for the spring 7. The lower spring portion 7b has a horizontally-disposed flat portion connected to the upper spring portion 7a by a curved portion 7g which engages the spring receiver 6 placed in contact with the transverse pressure receiving protrusion 1a of the tie 1. The free end 7e of the upper spring portion 7a is adapted to press against the upper side of the flange 3a. The free end 7c of the lower spring portion 7b is formed by bending the lower spring portion 7b into dog-leg or crank-shape having a vertical portion 7f which engages against the side edge surface of the flange 3a and an inturned portion which overlies the upper surface of the flange 3a with a space 8 between the underside of the free end 7c and the upper surface of the flange 3a. A hole 7d for receiving the head of the anchor 4 is formed in the lower spring portion 7b.
As shown in FIG. 4, the fastening element or member 5 has an insertion guiding portion 5d formed at the tip, a cam portion 5a for depressing the lower spring portion 7b of the spring 7, a detent portion 5c extending perpendicularly with respect to the cam portion 5a, and a hexagonal head portion 5b adapted to be engaged by a wrench, the portions being formed successively and continuously along the fastening member proper.
As best seen in FIG. 3b the anchor 4 has a root which is insulated by an insulating member 4b and which is buried in the tie 1. The head of the anchor 4 is exposed over the tie 1 and is received through the hole 7d of the lower spring portion 7b. A hole 4a is formed in the head of the anchor 4 for receiving the fastening member 5. As will be described, the fastening member 5 is inserted through the hole 4a and is turned to secure itself with respect to the lower spring portion 7b.
To assemble the rail fastening device, the spring 7 is fitted on the head of the anchor 4 and the spring receiver 6 with the free end 7e of the upper spring portion 7a placed in contact with the upper surface of the flange 3a and with the vertical part 7f pressed against the side edge of the flange 3a and with the curved part 7g pressed against the spring receiver 6. Thereafter, the fastening member 5 is inserted through the hole 4a formed in the head of the anchor 4 with the insertion guiding part 5d directed forward (downwardly in FIG. 5a) and the hexagonal head 5b directed rearward. During insertion, the cam section 5a is directed away from the rail. When the cam section 5a is aligned with the lower spring portion 7b, a wrench 9 is engaged with the hexagonal head 5b and is operated to turn the fastening member 5 as shown by the arrow in FIG. 1 into the solid line position. This causes the lower spring portion 7b to be depressed with the cam section 5a. Thereafter the fastening member 5 is driven into the hole of the anchor 4 by striking the hexagonal head 5b with a hammer until the detent surface section 5c of the fastening member 5 is engaged with a flat surface in the shaped hole 4a formed in the head of the anchor 4. This engagement prevents the fastening member 5 from turning in the reverse direction, i.e. in the direction opposite the arrows in FIG. 1. In this state, the underside of the free end 7c of the lower spring portion is spaced from the upper surface of the flange 3a by a suitable gap or space 8, for instance about 10 mm. The fastening member 5 can be removed by reversing the aforementioned procedure.
According to the rail fastening device of the present invention as described hereinbefore, when the rail is pushed outward with respect to the head thereof by a transverse pressure applied by trains, the rail tends to tilt or pivot lengthwise. This causes one flange to raise relative to the tie 1; however, the rising movement of the flange is restricted by the inturned portion of the free end 7c of the lower spring portion 7b. Thus, the free end 7c of the lower spring portion, and the thinner free end 7e of the upper spring portion of an optimum spring constant, cooperate to hold down the rail, while the vertical portion 7f of the free end 7c of the lower spring portion 7b restrains the rail from transverse movement. Accordingly, since the tilting of the rail can be effectively prevented, the derailing of trains due to increases in the track gauge can be prevented. Furthermore, since the rail fastening device of the present invention is not loosened by vibrations caused by trains, the disadvantages of the conventional bolt type fastening devices are eliminated. | A rail fastening device comprises a curved tapered spring having free ends adapted to engage a rail flange for preventing lateral and tilting motion of the rail. The spring is secured by a fastening element having a detent which is rotated and slid into a shaped hole in an anchor embedded in the tie on which the rail is supported. | 4 |
BACKGROUND OF THE INVENTION
This invention relates to a sewing machine, and more particularly to a bobbin thread detection apparatus for sewing machines.
Lockstitch sewing machines conventionally include a small amount of bobbin thread wound on a bobbin. Since the thread is used up in a relatively short period of time, an inspection is frequently required to determine how much thread remains on the bobbin. Such inspection has been generally made by tilting a head of the sewing machine. However, this extra labor inevitably lowers the efficiency of the sewing operation. For this reason, various approaches have been made to automatically inspect how much bobbin thread remains wound on a bobbin when the residual or leftover amount of bobbin thread is less than a predetermined minimal amount.
Apparatuses which measure the amount of residual bobbin thread are broadly classified into those which are adapted for mechanical inspection and those which are adapted for optical inspection. The mechanical inspection apparatuses are used, for example, when the user is required to inspect the residual or leftover bobbin thread while it is wound on the bobbin such as when detection elements are adjusted according to variations depending upon the condition of the workpiece and the sewing operation. This operation could not be performed unless the head of the sewing machine is tilted, which requires the use of much operator labor.
Lately, there has been a tendency that bobbin thread inspections be made using an optical sensor. For example, one conventional optical inspection apparatus for detecting the residual or leftover bobbin thread, as shown in FIGS. 10A and 10B, is provided with an optical sensor C. More specifically, the apparatus of this class comprises a bobbin B which includes a flange Ba having a plurality of reflective elements B1 radially and equidistantly formed thereon. The reflective elements B1 of the flange Ba are adapted to irradiate light from an illuminator C1 to the flange Ba. A light receptive element C2 converts the light which is continuously reflected from the reflective elements B1 into a pulse signal.
When the main shaft rotates one-half turn, the number of pulse signals generated is detected, thereby determining the rotation speed of the bobbin. This measured bobbin rotation speed is then compared with the rotational speed of a bobbin which contains the preset minimum amount of thread. If the measured rotational speed is more than the preset speed, the operator is notified that the residual or leftover bobbin thread remaining is low, so that a new bobbin may be applied.
In other words, to cope with the aforementioned situation where the rotation speed of the bobbin is increased as the residual or leftover thread is reduced, the rotation speed of the bobbin is measured to determine whether or not the amount of residual or leftover thread is less than the present minimum amount.
However, the aforementioned apparatus as those which are adapted so that the amount of the residual or leftover thread is detected by the rotation speed of the bobbin B, involve a disadvantage in that the rotation speed of the bobbin is subjected to the coefficient of friction between the bobbin B and a bobbin case (not shown), thus necessitating resetting its rotation speed when another bobbin is exchanged therewith.
Another disadvantage is that the rotation speed of the bobbin varies considerably even where the main shaft rotates one revolution, resulting in unreliable speed data due to instability, thereby resulting in malfunction. For instance, the bobbin B is initially rotated at a high speed immediately after the bobbin thread is pulled up by a needle thread loop, but is thereafter decelerated since its rotation entirely relies upon inertia, thus causing a great change in its speed. Moreover, sewing speed is not always constant during one sewing cycle and the rotation speed of the bobbin also varies considerably by a change in the rotation speed of the main shaft.
For these reasons it is very difficult to precisely detect the amount of the residual or leftover thread, thereby resulting in many malfunctions.
It is therefore an object of the present invention to eliminate the aforementioned disadvantages of the conventional apparatus for optically detecting the amount of the residual or leftover bobbin thread.
Another object of the invention is to provide an apparatus for detecting the amount of the residual or leftover bobbin thread, which is capable of reliably detecting the amount of the bobbin thread when the remaining thread reaches a predetermined minimal amount.
SUMMARY OF THE INVENTION
To accomplish these and other objects of the invention, a sewing machine is provided which includes an optical sensor, a detection mechanism and a counting mechanism. In preferred embodiments, the invention may include a bobbin having flanges with a plurality of reflective elements, wherein the flanges have a plurality of holes, an illumination mechanism to cast light upon the reflective elements, a receptor to receive and detect reflected light, a sensor to detect and a counter to count the revolutions of the main shaft of the sewing machine, a detector to detect and a comparator to compare the rotation speed of the bobbin with a preset value, a control, and an alarm.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described in greater detail below by way of reference to the attached drawings, in which:
FIGS. 1A and lB are perspective and front views of a bobbin according to a first embodiment of the invention;
FIG. 2 is a front view of a bobbin case;
FIG. 3 is a perspective view of a photo sensor;
FIG. 4 is a plan view of the photo sensor;
FIG. 5 is a simplified representation of the manner in which the photo sensor is illuminated;
FIG. 6 is a block diagram of the first embodiment;
FIG. 7 is a representation showing waveforms of the output pulse derived from the photo sensor and the edge detection circuit shown in FIG. 6;
FIGS. 8 and 9 illustrate a control flowchart;
FIG. 10A is a side view showing a photo sensor of a conventional apparatus for detecting the amount of the residual or leftover bobbin thread; and
FIG. 10B is a front view of the bobbin shown in FIG. 10A.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1A and 1B show a bobbin 1 which is rotatably mounted in a rotating hook well-known in the art. Bobbin 1 includes a takeup shaft 1a on which a bobbin thread is wound, and a pair of annular flanges 1b and 1c on the opposite ends of the takeup shaft 1a. The flanges 1b and 1c have a plurality of holes 1d and 1e through the flanges 1b and 1c, said holes concentrically and radially placed and equidistantly spaced along said flanges. In this connection, it is noted that the bobbin 1 is designed for general use and not specifically machined for the purpose of application of the instant invention. Holes 1d and 1e are of a type commonly found in bobbins, and are adapted for making bobbin 1 lightweight.
FIG. 2 shows a bobbin case 2 as found in one embodiment of the present invention. Said case has a notch 2a in its frame that exposes one of the holes 1d or 1e which are bored through flange 1b or 1c of the bobbin 1 which is placed within the bobbin case 2. Bobbin case 2 is also of a popular type generally used and not specifically configurated for use in the instant invention.
FIGS. 3 and 4 show a photo sensor 3 disposed facing a hook (not shown). The photo sensor 3 includes an illuminative optical fiber 3a or light emission element, and a light receptive optical fiber 3b or light receptive element. Light projected from the illuminative optical fiber 3a passes through the notch 2a in the bobbin case 2 and is then irradiated onto the flange 1b of the bobbin 1. As seen in FIG. 5, the emitted light strikes flange 1b or 1c, passes through holes 1d or 1e, and as the bobbin 1 rotates a moving circular locus PS is formed by the light passing through the center of said holes. Although the light projected onto the face of flange 1b is reflected, those light rays passing through the holes 1d are not. The light reflected off the flange face is then detected by the light receptive optical fiber 3b. This reflected light is then converted into an electrical signal, and this signal is then outputted to a sensor amplifier 4, as shown in FIG. 6. Thus, the light projected from the light receptive optical fiber 3b is intermittently reflected prior to rotation of the bobbin 1 so that the electrical signal outputted to the sensor amplifier 4 is a pulse signal, as shown in FIG. 7.
FIG. 6 is a block diagram of the apparatus according to the invention, in which there is shown an edge detection circuit 5 that outputs a fixed pulse signal S3 in response to both leading and trailing edges of a pulse signal S2 fed from the sensor amplifier 4. A sensor 6 detects the rotation speed of a main shaft of the sewing machine. Sensor 6 is adapted to output one pulse signal S4 for each revolution of the main shaft.
A signal processing circuit 7 includes first and second counters 7a and 7b. The first counter 7a is connected to sensor 6 and counts the number of pulses S4 outputted from sensor 6. First counter 7a outputs one pulse signal S5 to the second counter 7b when the accumulated count equals a predetermined value. This counting operation is repeatedly performed. Means for detecting the rotation speed of the main shaft is thus formed by the first counter 7a and the sensor 6. The second counter 7b (counting means) is connected to the edge detection sensor circuit 5. Second counter 7b counts the number of pulses outputted from edge detection sensor circuit 5 between the pulses outputted from the first counter 7a, i.e., second counter 7b counts the number of holes 1d found during one revolution of the bobbin. These counted pulse values S6 are then fed into a CPU 8 annexed thereto.
The counted values fed from the second counter 7b are stored in successive memory locations accommodated in the CPU 8. As is well known, a CPU such as CPU 8 performs various computing and control functions and, in this instance, it functions as a computer means, a control means, a comparison means, and a memory means. In response to an error signal S7 applied from the CPU, an interrupt signal generating circuit 9 transmits an interrupt signal S8 to a control circuit 10 for the sewing machine.
The manner of operation of the apparatus for detecting the amount of leftover bobbin thread arranged as aforementioned will be explained with reference to the flowchart shown in FIGS. 8 and 9. As shown in step 1, when the power is turned on, the respective parts of the instant apparatus as well as the sewing machine are initialized. In step 2, a stitch pitch p and a fabric thickness t, both in millimeters, are inputted by the operator via an input means (not shown). The CPU 8 in step 3 then calculates a threshold value for determining the amount of leftover bobbin thread according to the aforementioned data, as will be described later.
In step 4, a signal for starting the sewing machine is then inputted to the control circuit 10 to perform an operation designated by A, step 5 in FIG. 8. As shown more specifically in FIG. 9, first counter 7a counts the number of rotations of the main shaft of the sewing machine from pulses S4 from sensor 6.
A sewing operation is started to spend and pay out the bobbin thread in a fixed amount every stitch, thereby rotating the main shaft. This rotation allows photo sensor 3 to output the pulse signal S2 with a fixed pulse width, as shown in FIG. 7. A pulse signal S3 as illustrated in FIG. 7 is outputted from an edge detection circuit synchronously with the leading and trailing edges of the pulse S2. As shown in steps A4-A6 in FIG. 9, pulse signal S3 is inputted to the second counter 7b where the pulse number is counted.
The main shaft of the sewing machine is then rotated N turns (for example, 50 turns in this instance) to perform the sewing operation for N stitches, thereby outputting one pulse signal S5 from the first counter 7a to the second counter 7b. Thus, the counted value thusfar is outputted from the second counter 7b to the CPU 8, and stored in a memory location within CPU 8, as shown in steps A7 and A8. The aforementioned operation is repeated until one sewing cycle is completed to successively store the data for N stitches in the CPU 8, as shown by Step A9.
Referring now to FIG. 8, upon completion of one sewing cycle, CPU 8 evaluates the mean value of the counted values for each of N stitches as stored in the memory, and then stores this mean value in a fixed memory location. This most recent mean value is then compared to the previous mean value obtained during the sewing operation. Using this comparison, the CPU 8 calculates a coefficient of change between the mean values, as shown in Step 6. The CPU 8 then compares the calculated mean value with the aforementioned preset threshold value.
The preset threshold value is the pulse number count of pulse signal S3 outputted from the edge detection circuit 5 where the residual bobbin thread is at a predetermined level when a replacement bobbin is required. The payout amount L in millimeters of the thread per N stitches can be expressed by means of the following equation:
L=N ×(p+2×(t/2))
or more simply:
L=N ×(p+t)
where p is the stitch pitch and t is the fabric thickness.
On the other hand, the rotation speed c of the bobbin per the unit length can be obtained from the following equation:
c=K/(π×D)
where D is the winding diameter in millimeters of the residual thread still wound on the bobbin to be detected, and K is the pulse number.
The rotation rate c in this instance may be expressed by the following equation where the flange 1b of bobbin 1 is formed with eight holes to find in terms of 16 the value of K:
c=16/(π×D)
From the foregoing, the pulse number, namely, threshold P th which is obtained by the main shaft making N revolutions, provided that the winding diameter of the thread is D, is formalized as follows:
P.sub.th =c×L
which upon substitution becomes:
P.sub.th =16N ×(p+t)/(π×D)
According to the instant embodiment, CPU 8 is adapted to automatically calculate the threshold P th by causing the input means (not shown) to input the stitch pitch p and fiber thickness t so that the threshold P th may be readily set, as shown at step 2 in FIG. 8.
Where the mean value obtained during machine operation is more than the above calculated threshold P th value, CPU 8 outputs a control signal S7, which in turn allows an interrupt signal generating circuit 9 to output an interrupt signal S8 to a sewing machine control circuit 10. In this manner, the control circuit 10 is actuated, interrupting and stopping the sewing machine and also operating an alarm means, such as a buzzer or a lamp, thereby notifying the operator of a shortage of bobbin thread.
In the instant embodiment, detection of the amount of leftover thread is made according to a large number of rotations of the main shaft. Thus, measurement is not subjected to variations in sewing speed during each sewing cycle and the variations in the rotation speed of the bobbin while it turns. Further, the values as counted for every N stitches are averaged so as to minimize errors to a negligible extent, thereby ensuring a more accurate detection of the true amount of residual thread remaining even if one particular value varies greatly from the others.
Since the possibility of error is reduced in computing the pulse values for the bobbin rotation, these errors need not be considered. If errors are not taken into account, then the counted value may be compared with the threshold after every N stitches. In this instance, another advantage is obtained in that a shortage of the amount of residual thread may be detected during a single sewing cycle, as compared with what is discussed in the above embodiment.
In accordance with the embodiment, a coefficient of change may be calculated according to the latest mean value as calculated and the previous mean value as calculated by the sewing operation so that the operator is able to determine how much thread remains. For this reason, it is possible to prepare the next bobbin beforehand, thereby improving operation efficiency.
Although each of the steps of the routine identified as A1-A9 of FIG. 9 are carried out by a signal processing means which is provided with the first and second counters, this is also made by means of a control circuit such as a CPU or the like which performs the same functions. It is noted that the invention is not limited to the aforementioned embodiment.
The overall operation of the present invention is as follows. The pulse number transmitted from the light receptive element is counted at every fixed rotation of the main shaft in response to the light reflected from the flange of the bobbin. These counted values are successively taken up during one sewing cycle and compared with the fixed threshold value by the comparison means. This threshold is the value which is transmitted from the light receptive element by rotating the main shaft a fixed turn where the amount of the residual thread remaining on the bobbin is low. A comparison is made between the threshold value and the counted value. Where the counted value is more than the threshold value, an alarm means is activated, thereby notifying the operator that the amount of leftover thread is less than the predetermined fixed amount.
In other words, the number of rotations of the bobbin with respect to the rotation speed of the main shaft are detected, thereby detecting the amount of residual thread. Thus, an accurate detection of the amount of residual thread may be made without being affected by a change in the rotation speed of the bobbin during one sewing operation or one revolution.
Moreover, the many counted values obtained whenever the main shaft is rotated a fixed number of turns, as aforementioned, are successively stored during each sewing cycle. The mean value of these computed values for one sewing cycle is calculated and compared with the threshold value. Errors produced in calculating the threshold value may thus be minimized to a negligible extent, thereby ensuring an accurate detection of the amount of residual thread.
Although the invention has been described with a preferred embodiment, it is to be understood that various changes, substitutions and alterations can be made therein without departing from the spirit and scope of the invention as defined by the appended claims. | A residual bobbin thread amount detection apparatus for a sewing machine which includes a hook rotating in association with a main shaft of the sewing machine and a bobbin rotatably mounted on the hook. A first detector detects the rotation speed of the main shaft and a second detector detects the rotation speed of the bobbin. A comparator responsive to the second detector generates a signal when the rotation speed of the bobbin exceeds a predetermined value, whereby a controller operates an alarm. | 3 |
This is a continuation-in-part of application Ser. No. 08/320,975, filed Oct. 6, 1994, now U.S. Pat. No. 5,467,441, which is a continuation of U.S. Ser. No. 08/096,131, filed Jul. 21, 1993, now abandoned.
CROSS REFERENCE TO OTHER APPLICATIONS
The present invention is related to other inventions that are the subject matter of concurrently filed, commonly assigned U.S. patent applications having the following serial numbers and titles: Ser. No. 08/096,521, now U.S. Pat. No. 5,652,851, User Interface Technique for Producing a Second Image in the Spacial Context of a First Image Using a Model-Based Operation, which is hereby incorporated by reference herein; Ser. No. 08/096,200, now U.S. Pat. No. 5,596,690, "Method and Apparatus for Operating on an Object-Based Model Data Structure to Produce a Second Image in the Spacial Context of a First Image"; Ser. No. 08/096,193, now U.S. Pat. No. 5,479,603, "Method and Apparatus for Producing a Composite Second Image in the Spatial Context of a First Image", which is hereby incorporated by reference herein; Ser. No. 08/095,974, "User-Directed Method for Operating on an Object-Based Model Data Structure Through a Second Contextual Image"; and Ser. No. 08/320,975, now U.S. Pat. No. 5,467,441, "Method for Operating on Objects in a First Image Using an Object-Based Model Data Structure to Produce a Second Contextual Image having Added, Replaced, or Deleted Objects".
FIELD OF THE INVENTION
The present invention relates generally to a method of operating a processor-controlled machine having a display for displaying images, and to a processor-controlled machine operated according to the method. More particularly, the present invention relates to producing a human perceptible output related to the image display features presented in a first displayed image by operating on the model data structure from which the first displayed image was produced. At least one distinct input region is provided and located coextensive with the first displayed image, and at least one distinct output region is provided spatially separate from but in some manner linked to the input region, the output region being used to display the human perceptible output.
BACKGROUND
A frequent and powerful use of a processor-controlled machine such as a computer is the presentation of information in the form of images on a display device connected to the machine. An image, which may include characters, words, and text as well as other display features such as graphics, is produced in a display area of the display device directly from an image definition data structure defining the image; the image definition data structure is typically stored in a memory area of the machine. One type of image format known as a raster image is composed of individual image locations commonly referred to as "pixels". The discussion of images herein will generally reference pixel data, but it is to be understood that other data formats, such as vector data, may also be used to define an image. The images discussed herein may be either static (having the appearance to a system operator or user of not moving) , or animated, as, for example, in the case of a digital video image.
An image definition data structure alone carries relatively limited data about the information content of the image the data represent. However, for many images, the image definition data structure is itself generated from another data structure which contains information or data capable of being understood by a human or by a software operation such as an application program which is executed by the machine's processor. Such a data structure will be referred to herein as the "information model data structure" or the "model data structure", and is to be distinguished from the image definition data structure. Examples of information model data structures include scene description models used by rendering operations to produce graphic images such as photorealistic scenes; document models used by a word processing or other document manipulation application which contains the text, formatting instructions, and other data needed for producing a formatted document; graphical object data structures used by illustration and painting software programs; spreadsheet model data structures used by spreadsheet application programs for presenting spreadsheet images; and numerous application-specific models, such as those used for computer-aided engineering, simulation and manufacturing applications.
In some systems providing user access to the model data structure, a user may be able to access, and perhaps affect or manipulate, data and information that is not represented by display features currently visible in the original image by producing, through alternate functions defined by the application, a second or alternate view of an original displayed image. The second view may provide enhanced information about the model data structure, or the system may then permit interaction with data in the model through the display features present in the second view.
Typical of many of the systems implementing these types of multiple views of a model, the spatial relationship between the original image, the specification of the input content for the second image and the position of the second image in the display is not easy to visualize. While the specification of the input may be directly related to the first image (i.e., when the user can point to or select a region in the first image) this is not always the case as, for example, when the user has to type commands to specify a second image. Furthermore, once a selection is specified, the user either has no control over the location of the second image, or must reposition it in a separate step. Therefore, it can be difficult to understand how the second image is spatially related to the first image and to the model. Linking direct selection in the first image to the spatial position of the second image can make these relationships more clear. This can be especially important when the model is complex and can be viewed in many different ways. As systems supporting complex models, or sets of related models, are becoming more common, this problem is becoming more critical.
An example of providing a user with simultaneous control over both first image portion selection and second image display location is a software implementation of magnification as disclosed in U.S. Pat. No. 4,800,379. Another example of the display of a second image in the spatial context of a first image is disclosed in EPO 0 544 509, entitled "Photographic Filter Metaphor for Control of Digital Image Processing Software".
Operations on the image pixel data structure alone, such as those disclosed in U.S. Pat. No. 4,800,379 and EPO 0 544 509, however, provide versions and views of the first image which are limited strictly to manipulations of pixel values. So, while a typical software implementation of a pixel magnifier provides some desirable features for generating the simultaneous display of two images, the range of information content possible in the second image which is derived directly from the image pixel data structure of the first image is necessarily limited to versions and views of the first image which result only from operating on the pixel values. When information about the first image is available from the information model data structure of the first image, the methods used for operating on the image pixel data structure to produce image (pixel) magnification are not transferable to operating on the information model data structure to provide alternate views of the first image. As a result, such methods are inoperable for use in accessing alternative views of an information model data structure, or for producing a composite second image in the spatial context of a first image.
Copending, concurrently filed, commonly assigned U.S. patent applications Ser. No. 08/096,521, "Method and Apparatus for Using the Model Data Structure of an Image to Produce Human Perceptible Output in the Context of the Image" and Ser. No. 08/096,200, "Method and Apparatus for Using an Object-Based Model Data Structure to Produce a Second Image in the Spatial Context of a First Image" solve this problem of providing a second view of an original image in the spatial context of the original image by providing methods for operating a processor-controlled machine that operate on a model data structure from which a first image has been produced in order to produce a second image for display in the spatial context of the first image.
In these applications a viewing operation region (VOR) is displayed coextensively with a first image segment of the first image in the display area of the machine's display device. The first image segment includes a display feature representing a model data item in the model data structure. In response to the display of the VOR, the method operates on the model data item in the model data structure to produce a second image for display in the VOR showing information related to the display feature in the original image.
The above referenced and incorporated applications (i.e. 08/096,521, 08/096,200, 08/096,193, 08/095,974 and 08/320,975) define a "viewing operation region" (VOR), (also referred to as "output producing region") as a region having an arbitrarily shaped, bounded area. A viewing operation region is described as an example of a "workspace", and a "workspace" is defined as a display region within which display features appear to have respective relative positions. Presenting a workspace that includes plural display features produces human perceptions of the display features in respective positions relative to each other. A "window" is given as an example of a workspace.
The viewing operation region (VOR) of the referenced applications may also be called a "lens". A lens can have various attributes such as "magnification" capabilities, "x-ray" capabilities, "dashed line" capabilities, etc. The VOR or lens has an input region located coextensively with a position of a first image segment which is to be acted upon.
An output region of the VOR or lens has been described as being configured in the same area as the input region. The rendered second image is defined to have size and shape dimensions "substantially identical" to size and shape dimensions of the VOR or lens. The second image is presented in the VOR or lens substantially at the same time as the first image is being displayed in the display area. Since the VOR or lens is located in a position in the display area coextensive with the position of the first image segment, presentation of the second image in the viewing operation region replaces the first image segment in the display area.
A method according to the cited applications is described in FIG. 1A according to designated method 10 and illustrated in FIGS. 1B and 1C. It is to be appreciated that method 10 is provided as an illustration and other methods may also be used in connection with the subject invention, such as those further disclosed in co-pending Ser. No. 08/096,521, which has been incorporated by reference.
In FIG. 1B first image 20 in a display area 22 includes figures "x" and "o" in black, solid (or unbroken) lines. The figure "x" is labeled as displayed feature 24, and the figure "o" is labeled as displayed feature 26. A display feature attribute data item included in the first image model data structure has a present attribute value of "solid" giving both figures (i.e. "x" and "o") their solid outlines. The first image model data structure is discussed in detail in U.S. Ser. No. 08/096,521 incorporated by reference, see Figure 6 of that application and the associated discussion.
As set forth in box 12 of FIG. 1A, a request is received to display VOR 28 in a present viewing position in display area 22 coextensive with the present image position of a first image segment of first image 20. The first image segment includes first display feature 24 and display feature 26. In response to the display request, the method includes, as stated in box 14 of FIG. 1A, obtaining a new attribute value for the display feature attribute data item. The new attribute value indicates a modified first display feature. Particularly, a display feature having dashes or dots. In response to this request, a second image is produced having size and shape dimensions substantially identical to the size and shape dimensions of the viewing operation region (see FIG. 1A, box 16). The result of the processing produces the presentation of a second image including the modified first display feature in VOR 28. VOR 28 replaces the first image segment in the display area (FIG. 1A, box 18). In FIGS. 1B and 1C, the input region of the VOR and the output region are substantially identical in size.
FIG. 1C graphically sets forth the results of this method which produces a second image in place of the solid outline figures "x" and "o" originally produced in the first image segment. Figures "x" and "o" each have the new attribute value indicating a "broken" line.
As this example illustrates, since the second image is in the same area as the first image segment, the first image segment is obliterated. Further, when a VOR, such as a "magnification" VOR, which has an output region larger than its input region is used, material adjacent to the first image segment can also be obliterated, thereby covering up material which may be pertinent to a user.
SUMMARY OF THE INVENTION
The subject application extends the invention set forth in the previously cited applications. In those applications a method and apparatus was described which included the use of viewing operation regions (VOR) as tools for visualization and interaction consisting of a movable, arbitrarily shaped region and an arbitrary filter. Positioning a VOR over a rendering of some model provides an alternative view of the model inside the region of the VOR. The basic concepts of VORs have been disclosed in U.S. Ser. Nos. 08/096,521, 08/096,200, 08/096,193, 08/095,974, 08/320,975. These applications describe in detail VORs with a single explicitly manipulable region. They also include descriptions of VORs that have different sized regions. For example, a "magnification" VOR, will have an input region smaller than the output region. Another example of this is when a VOR provides a definition for words in a text document; the definition will take up much more space than the word. Application Ser. No. 08/096,193 discloses combinations of VORs called composition VORs. It is to be appreciated that the teachings of this application extends to these VORs.
As generally noted above, when a generated output region is larger than the input region, in addition to the first image segment being obliterated, information in proximity to the first image segment may also be lost. FIGS. 2A-2B illustrates this situation. The magnified image "M" in input region 30 of VOR 28 has an output region 32 (FIG. 2B) larger than input region 30, therefore detail outside of the input region is lost (i.e., the letter "a" cannot be seen in FIG. 2B) . In some instances, this information is of particular importance to a user. In consideration of this, a manner in which such information can be maintained would be very desirable.
The inventors of the subject invention have determined that this problem may be solved by designing VORs having explicit multiple regions. The VORs according to the subject invention include at least one explicit input region and at least one visually separated explicit output region. The at least one input region and at least one output region are visually or in some other manner linked, such that a user is able to determine the connection between the regions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a flow chart illustrating the acts of the method of operating a machine according to the present invention, which produces image definition data defining a second image including a modified first display feature;
FIGS. 1B and 1C illustrate a sequence of display screens showing the first image and the second image produced according to the method illustrated in FIG. 1A;
FIGS. 2A and 2B illustrate a "magnification" VOR with an output region larger than an input region;
FIG. 3 illustrates VOR with an explicit input region and a spatially separate explicit output region;
FIGS. 4A and 4B illustrate a VOR as depicted in FIG. 3, with bold lines and dashed lines replacing the shaded area;
FIGS. 5A-5E illustrate a "magnification" VOR with an adjustable output region;
FIGS. 5F-5G are algorithms for the adjustable output region of FIGS. 5A-5E;
FIGS. 6A-6B illustrate an override of offset values for an output region;
FIG. 6C is an algorithm for the output region in FIGS. 6A-6B;
FIGS. 7A-7B are diagrams of a display with a VOR having explicit input and output regions linked by resizing characteristics of the regions;
FIGS. 8A-8C set forth diagrams of a display with a VOR having explicit input and output regions linked by color coding and geometric similarities of the regions;
FIGS. 9A-9B provide an illustration of a VOR with a single input region and a plurality of output regions;
FIG. 10 illustrates a VOR embodiment which includes multiple input regions and one output region;
FIG. 11 provides a description of an embodiment where different regions can be moved with respect to each other;
FIG. 12 depicts operation of a VOR where the input region is a line selection;
FIG. 13 is a display screen showing different configurations of a viewing operation region;
FIG. 14 is a block diagram illustrating the interaction between the components of an illustrated embodiment of the method of the present invention; and,
FIG. 14A is a variation of the block diagram in FIG. 14 illustrating an alternative implementation of the method of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A viewing operation region (VOR) 28 with an explicit input region 30 and an explicit output region 32 is illustrated in FIG. 3. In FIG. 3 the output region 32 is visually separated from the input region 30. A visual connection between these regions is achieved by using a shaded area 34 to visually link the input region and output region. While the shaded area provides a visual link between the regions, it does not hide the information located thereunder. Rather, a user is able to view the material within shaded area 34.
Rendering of a second image in the output region 32 is accomplished in the same manner as for VORs having a single explicitly manipulable region as disclosed in the co-pending applications. However, a difference which exists is that in the construction or generation of VORs according to the subject invention, the output region is distinct (i.e., an explicit region) from the input region. This distinguishing may be accomplished by providing a predetermined distance between the regions, providing unique shapes to the regions, or in some other manner. Distancing can be achieved by providing a predetermined offset value between the input region and the output region when the VOR is constructed.
It is to be appreciated that whereas in FIG. 3 a shaded area 34 is used to visually link the input region 30 with the output region 32, other manners of showing the association or connection of the regions are possible, including, as illustrated in FIGS. 4A and 4B, replacing shaded area 34 with bold 36 or dashed 38 lines connecting the explicit regions. In addition, the lines may be displayed having a color which enhances the visual linking.
Explicit input and output regions are considered useful in many situations, including implementation in definition and translation of text, and in general, in any situation where the output region is larger than or of a different semantic type then the input region.
An issue with respect to the concept of separate explicit input and output regions is that these regions need to be linked together to allow them to move together or in some other way are linked so that a user can easily determine that they are associated with each other.
The linkage between the input and output regions does not need to be fixed or rigid. For example, with a magnification VOR 28 as depicted in FIGS. 5A-5B, as the VOR 28 is moved so the input region is placed over different images, these different images will be magnified. However, as shown in FIG. 5B, when the input region is moved towards, for example, the right-hand edge of display area 22, the output region 32 of VOR 28 will encounter the edge of display area 22, thereby not permitting observation of the area of the map on the right edge, without repositioning the map. By observation we mean both simply viewing the area of the map and making it possible to locate the input region 30 coextensive with images located in the now observable area.
To address the above situation VOR 28 is constructed such that the spatial relationship between the input region and output region is adjustable. Particularly, as illustrated in FIGS. 5C-5E when the method senses that a section of the output region 32 is at the edge of the display area 22, new offset values replace existing offset values. The changing the offset values causes the output region 32 to adjust its spatial relationship relative to the input region 30. As FIGS. 5C-5E show, the output region 32 can be shifted, for example, to the upper left side of the input region (FIG. 5G), the lower left side of the input region (FIG. 5D) or the lower right side of the input region (FIG. 5E).
The adjustment of the output region can be implemented in an variety of ways. FIG. 5F provides a method of automatically providing a default position. The method includes a step 40 that senses when a portion of the output region is at the edge of display area 22. When this occurs a set of predetermined default offset values replace existing offset values, in order to adjust the output region of the VOR (step 42). In step 44 the output region is redisplayed at a new location.
Alternatively, a method accomplished by steps 46-54 of FIG. 5G can determine which of a set of possible positions result in the greatest distance from the edge of the display area 22, and output region 32 is repositioned accordingly.
A further alternative to the above operation is illustrated by FIGS. 6A-6B, wherein upon reaching the edge of display area 22 the offset values used in configuring VOR 28 are overridden such that the output region 32 is maintained at the edge of the display area 22 as the input region 30 continues to be moved towards the right edge. In this manner, the input region 30 moves towards the output region 32. This implementation may be appropriate in situations where the portion of the map, etc. which is obliterated or hidden is not of great concern and the area which is of most interest can be obtained through the override procedure. FIG. 6C provides a method in steps 56 and 58 for accomplishing the above actions.
In a further embodiment of a VOR with explicit input and output regions, a VOR according to the subject invention may also be configured to link the explicit regions with one another without the use of direct visual connections, such as the shaded area or lines of the previous embodiments.
FIGS. 7A-7B illustrate an implementation of a VOR 28, having explicit input and output regions. The regions are linked in that resizing one region (e.g. 30 to 30') resizes the other region (e.g. 32 to 32'). However, moving one region (e.g. 30') does not move the other region (e.g. 32').
Another embodiment of a VOR 28 having an explicit input region and explicit output region is depicted in FIG. 8A, wherein the input region is outlined or shaded in a particular color, such as red. The red outlined or shaded input region 30 is linked with an output region 32 also outlined or shaded in red.
This type of linking is especially useful in situations where multiple VORs 28, 28' (FIG. 8B) are used in the same image or document. For instance, when a plurality of VORs are in use, those of the same color (e.g. red with red, blue with blue) is easily associated with each other by a user. It is to be appreciated that in place of using colors, VORs 28, 28' with explicit input and output regions, can use geometric shapes to provide visual association (FIG. 8C) . As one example, a rectangular input region 30 is associated with a rectangular output region 32 whereas a circular input region 30' is associated with a similar circular output region 32'.
In yet another embodiment depicted in FIGS. 9A and 9B, a VOR with regions consisting of more than one shape are possible. An original image 30a of FIG. 9A, located coextensively with an input region 30 of VOR 28 having multiple output regions allows the generation of multiple output images 32a-32d, varying, for example, the percentage of color tint for each.
In a related concept, the VOR 28 in FIG. 10 illustrates an embodiment which includes multiple input regions 30, 30' wherein the results of processing in the input regions 30, 30' are combined into one output region 32, accomplished by overlapping.
FIG. 11, extends the concepts of the embodiment disclosed in connection with FIG. 10, providing a VOR 28 where the explicit regions can be moved with respect to each other. Particularly, in this example, all three regions may be individually positioned, the positions of the regions being under user control.
In still another embodiment of the subject invention, the input region 30 is specified by a line or point selection (FIG. 12). In the VOR of FIG. 12, the definition of a word is generated by selecting a word through the input region (i.e. the line selection) 30 of a VOR 28 with explicit regions. The user selects the word by clicking the mouse. In one design the definition does not change if the line selection of the VOR moves. Other designs for the same VOR include the use of a "hot spot" on the VOR that corresponded to the line or point selection. In this implementation, the definition continuously updates as the line or point selection is moved.
As in the co-pending applications, the linking between the input region and output region is constructed to allow for a constant tracking of the changing information in a smooth manner.
VORs according to the subject invention may have a topologically complex boundary, need not be a fixed or predetermined shape, and need not have an explicitly drawn border as long as it is perceptible as a coherent, distinguishable area. Thus, in the illustrated embodiments in which the user interacts with the VOR, the VOR must be sufficiently perceptible to allow the user to locate the VOR in the display and to attach the tracking symbol or cursor. In addition, the VOR need not be a single bounded area, but may be two or more contiguous or noncontiguous bounded areas that function together as a single bounded area would.
FIG. 13 shows VOR 60 and VOR 62 in display area 22 to further illustrate the variety of shapes that the VOR may have. VOR 62 is bounded by both exterior circular boundary 64 and interior circular boundary 66; the region inside boundary 66 is not included in VOR 62. VOR 60 includes five noncontiguous regions that function together as a VOR. FIG. 13 illustrates VOR 60 moving along the dotted line arrow from a first position shown in the dotted line boundary.
In the above embodiments, the VOR is implemented in a subwindow and can be manipulated like other subwindows using conventional window manipulation techniques. For example as previously discussed, the VOR can be resized by the user, and otherwise moved in any conventional manner. A mouse click can be used to select an unselected VOR, and to deselect a selected VOR.
To accommodate other useful functionality, a series of displayed features operating as buttons can be implemented for hiding a displayed VOR from view (i.e. making it "invisible"), when the user wants to view the first image without the input region of the VOR, and for exposing a previously hidden VOR. The method may also support an irregularly shaped VOR, with the operating buttons associated with either the input region, the output region, both regions or at some distinct location, for drawing a new shape and adding or subtracting it to the VOR as currently shaped.
There may also be such operating buttons for creating a VOR and associating it with its desired functionality using conventional menu techniques, and for deleting a VOR from the display area. Through these operations a VOR can be created having at least one explicit input region and at least one explicit output region separated from, but linked to, the input region.
The discussion which follows provides a description of an illustrated embodiment of a graphical object implementation according to the subject invention. Described is the system environment for the user interface implementation. It is to be appreciated that this material is set forth as one embodiment of the method according to the present invention. This discussion is similar to that set forth in Ser. No. 08/096,521, incorporated by reference, under the entitled section, "Description of an Illustrated Embodiment of a Graphical Object Implementation." For convenience of the reader, the numerical designations have, where possible, been maintained with those of the incorporated application to improve reference to that application.
A current embodiment of the method of the present invention has been implemented as a set of interactive user-controlled functions, or viewing operations, cooperating with the functionality of a graphical object editor application software program which operates in a graphical user interface system environment. Each viewing operation operates on the object-based model data structure of the graphical objects editor, hereafter called the graphical editor data structure, which has structural features similar to model data structure described earlier (This material has been fully detailed in U.S. Ser. No. 08/096,521, incorporated herein). The implementation of one of these viewing operations, designated as method, or viewing operation, 400, will be described in detail below. The structure of this programming environment will be described with reference to the simplified functional block diagram of FIG. 14 with the understanding that these functional components are common to a wide variety of machines supporting graphical user interface environments.
The illustrated embodiment has been implemented on a Sun Microsystems SPARCstation 10 computer as a research software prototype application written in the Cedar programming environment, a Xerox proprietary research software environment, utilizing the Cedar programming language, and running on the SunOS UNIX-compatible operating system. The Cedar programming environment provides application support for a graphical user interface environment including software functions both for presenting and managing images for display in plural workspaces or "windows" in the display area of the display, and for interfacing with at least one pointing device, to be manipulated by a user of the machine. The user uses the pointing device to communicate operational commands to the graphical user interface, and, through the interface, to each software application operating in each window.
The illustrated implementation also operates within the framework of an editing environment known as MMM (Multi-Device Multi-User Multi-Editor). MMM operates as a single window in the Cedar programming environment, and allows for multiple applications, including the graphics editor application, to execute as subwindows within the MMM window. MMM takes events from multiple input devices, such as a mouse and a trackball, keeps track of which device produced which event, and places all events on a single queue. It dequeues each event in order and determines to which application that event should be delivered. MMM applications are arranged in a hierarchy that indicates how they are nested on the screen. Each event is passed to the root application, which may pass the event on to one of its child applications, which may in turn pass the event on down the tree. Mouse events are generally delivered to the most deeply nested application whose screen region contains the mouse coordinates. However, when the user is dragging or resizing an object in a particular application, all mouse coordinates go to that application until the dragging or resizing is completed. Keyboard events go to the currently selected application. Additional information about the MMM environment may be found in Eric A. Bier and Steve Freeman, "MMM: A User Interface Architecture for Shared Editors on a Single Screen" in the Proceedings of the ACM SIGGRAPH Symposium on User Interface Software and Technology (Hilton Head, S.C. Nov. 11-13, 1991), ACM, New York, 1991, at pp 79-86.
In the illustrated implementation, the MMM editor is the root application and its window contains all other relevant application windows. In this case, those other applications include viewing operation 400 and Gargoyle graphics editor 120. MMM thus acts as a signal director between viewing operation 400 and application 120. In the illustrated implementation, viewing operation 400 is one of several tools that may be placed on a transparent overlay. The use of viewing of operation 400 in conjunction with the transparent overlay is described in more detail in concurrently filed, copending, and commonly assigned U.S. patent application Ser. No. 08/096,521 entitled "User Interface Having Movable Sheet with Click-Through Tools". For purposes of describing the illustrated embodiment herein, the processing interconnections between the viewing operation 400 and the transparent overlay are not significant and will not be discussed.
In addition, for simplification, the functionality of the MMM environment will be presumed to be incorporated directly into the window management system 112, and references to the "window manager 112" hereafter will presume to include the functionality of the MMM editor in the illustrated implementation.
The underlying structure of the Cedar environment, designated collectively as reference numeral 118 in FIG. 14, is a collection of components, including window management system 112 and operating system 114, that are arranged in hierarchical layers, supporting a well integrated, interactive environment in which lower level modules remain directly available to higher level, or "client" programs, callable as ordinary Cedar language procedures. In addition, a higher level Cedar component can supply a procedure value as a parameter to a lower level service procedure, which in turn can later invoke the higher level component to communicate with it as necessary.
Cedar environment 118 controls different application contexts controlled by a processor (see for example processor 140 of FIG. 46 and related discussion in U.S. Ser. No. 08/096,521, incorporated by reference) by separating them physically into different parts of one or more display screens. Application programs, such as the Gargoyle graphics editor 120, in the Cedar programming environment are called "clients" of the environment. The Cedar environment includes a high-level software window management system 112, hereafter called "window manager 112", which provides the necessary window management control for the application client programs that execute on the machine. Window manager 112 allows programmers and programs to create, destroy, move, and realize a hierarchical system of defined individual viewing areas in display area 180 of display device 170 called "windows". Each window is a region whose position and size is managed by the window manager 112, but whose contents are determined by the client application which creates the window. Window manager 112 also permits the client application to create nested subwindows to handle certain lower level functions within top level windows. Window manager 112 redisplays the contents of each window based on client-supplied specifications whenever the window's contents, size, or location changes. Windows are implemented by a client application as a set of window classes. A window class implementation provides operations to initialize a window, to save its contents, to destroy a window, to paint its contents on the display, and so on, and each member of a specific window class shares these same behaviors.
Viewing operation software 400 contains the software instructions for defining and implementing a viewing operation according to the method of the present invention and for interacting with the graphical editor data structure used by Gargoyle graphics editor 120 in order to produce the second image. Viewing operation 400 cooperatively interacts with the functionality of the Gargoyle graphics editor 120, and is a client of window manager 112, as is Gargoyle graphics editor 120. Each application client exchanges data with user interaction device 154 and display 170, via window manager 112 and output display circuitry 160, by converting signals received from input circuitry 152 into a series of user input signals for directing control of a processor (see for example processor 140 FIG. 46 and related discussion in U.S. Ser. No. 08/095,598, now U.S. Pat No. 5,581,670, incorporated by reference) to perform the operations of Gargoyle graphics editor 120 and to perform viewing operation 400, including creating and drawing the viewing operation region, VOR, 186 in window 211, on display 170, in response to request signals from the user.
The Cedar programming environment also includes a high-level, device independent graphics software application known as the Imager that provides high quality two-dimensional display of text, line art, and scanned images. The imaging model for the Imager is based on the Interpress page description language, which is similar to PostScript. The Imager handles all display output for all applications, including window manager 112, as well as for other programs (not shown) implemented in the Cedar environment. The Imager supports the presentation of a variety of image material: text in various fonts, lines and curves of various thickness, strokes or enclosed outlines, sampled images, and various color models. Image transformations can scale, rotate, translate, and clip images through simple specifications. The device's independent design permits images to be rendered on a variety of devices, some of which include full-color displays, color-mapped displays, black and white displays, and printers.
In the illustrated embodiment, window manager 112 includes input handler software (not shown) which collects, interprets, and parses the input data stream of user input requests and data into appropriate input signals for further action. Two modes of input handling are provided by window manager 112. In one mode, input signal management produces a single serial buffer of time-stamped input events from supported input devices, which in turn may be independently extracted by an application client if needed for processing a particular user event or response. In the second mode, called the Terminal Input Processor (TIP), input signals are interpreted based on specifications that are parsed into TIP tables (not shown). For each event, or event sequence, a TIP table entry specifies a sequence of action tokens that represent the semantics of the event. In the MMM framework of the illustrated embodiment, the functionality of the TIP is handled in MMM, and Cedar's TIP is not used.
In the illustrated embodiments, a three-button mouse provides the primary method for a user to send signals to viewing operation 400 requesting the display of the VOR 186. The mouse is connected in a conventional manner to user input circuitry 152. However, user interaction device 154 may include any suitable device for interacting with the viewing operation region 186 and other objects displayed on display device 170, including but not limited to pointing and cursor control devices for two and three-dimensional displays, such as a light pen, track ball, joystick, or data glove device, a touch screen display, and alphanumeric devices such as a keyboard. Alternatively, the user interaction device 154 may be a speech recognition device for speaking input, or a location sensing device for gestural input.
Additional information regarding the Cedar programming environment may be found in D. Swinehart, et al., "A Structural view of the Cedar Programming Environment", ACM Transactions on Programming Languages and Systems, Vol. 8, No. 4, October 1986, pp 419-490, and in W. Teitelman, "A Tour Through Cedar", IEEE Software, Volume 1, No. 2, April, 1984, pp. 44-73, both of which are hereby incorporated by reference herein. Additional information regarding the Gargoyle graphics editor may be found in K. Pier et al., "An Introduction to Gargoyle: An Interactive Illustration Tool", Proceedings of the Intl. Conf. on Electronic Publishing, Document Manipulation and Typography, (Nice France, April) Cambridge University Press, 1988, pp. 223-238, which is also hereby incorporated by reference herein.
In the illustrated embodiment, method 400 is implemented as a separate application, and the MMM editor handles any interaction between application 120 and method 400. However, as shown in FIG. 14A, the method of the present invention may also be implemented as a functional enhancement to application 120 which interacts with window management system 112 in graphical user interface environment 118 as collective entity 122. Method 400 may be implemented in this manner to operate in any of the variety of graphical user interfaces currently available for computer workstations and other types of machines having processors and displays, including personal computers, fully-featured copier-duplicators, production publishing machines, and image reproduction machines. The method of the present invention may be implemented in a variety of hardware and software environments that provide the window management and graphics software support functions equivalent to those described herein with respect to the illustrated embodiment.
It is therefore evident that there has been provided in accordance with the present invention, a method of operating a machine, as well as a machine, that fully satisfy the aims and advantages set forth herein. While this invention has been described in conjunction with specific embodiments, many alternatives, modifications and variations will be apparent to those skilled in the art. The specific embodiments illustrated and discussed herein are by no means exhaustive of all possible categories and instances of method implementations, and the invention as herein described is intended to embrace all such alternatives, modifications and variations as fall within the scope of the appended claims. | A method of operating a processor control machine, and a machine having a processor for producing human perceptible output related to an image display feature presented in an original image using the model data structure (the model) from which the original image was produced. In response to the display of an output producing region displayed coextensively with the first image segment including a display feature representing a data item in the model, a human perceptible output is produced using the data item. This is done at the same time as the first image is being displayed, giving the perception to a machine user of providing information related to the display feature in the first segment. The human perceptible output is a second image displayed by the output producing region, called a viewing operation region, or VOR. The VOR consists of one or more explicit input regions and one or more explicit output regions, spatially separated from the one or more input regions. The VOR, nevertheless, functions to bind or link the second view in the output region to the original image associated with the input region. | 6 |
TECHNICAL FIELD
[0001] The present invention relates to a base resin for a soldering flux, a soldering flux, and a solder paste.
BACKGROUND ART
[0002] Surface mounting on a circuit board typically involves the following procedure. A solder paste, which is a mixture of a flux and a solder powder, is supplied to electrodes on a circuit board by using a technique, such as screen printing and extrusion from a dispenser, and electronic components, such as capacitors, are subsequently mounted on the circuit board. The circuit board is then heated in a reflow oven to fuse the solder powder, thereby joining the electronic components and the electrodes.
[0003] Natural rosin has been widely used as a base resin for flux. However, natural rosin is highly susceptible to oxidation due to the presence of a significant amount of abietane-type resin acids (e.g., abietic acid, levopimaric acid, and palustric acid), which contain a conjugated double bond intramolecularly, and therefore natural rosin exhibits less thermal stability (e.g., easily discolored when heated). Thus, the use of natural rosin as a base resin for flux sometimes makes it difficult to conduct downstream inspection and cleaning procedures because the resulting flux residue at the soldered joints becomes dark-colored, and migration is induced due to the cracks formed in the residue. These problems become more serious when using a lead-free solder powder, which has a high melting point.
[0004] In order to solve these problems with regard to flux residue, Patent Documents 1 to 3, for example, propose the use of, instead of natural rosin, a rosin (disproportionated rosin or hydrogenated rosin) whose content of abietan-type resin acids having a conjugated double bond is reduced to an amount of not more than 30 wt %, as a base resin. However, fluxes containing the rosin tend to exhibit impaired fluidity over time. Further, it has been revealed that solder pastes containing the fluxes are likely to become increasingly viscous, and easily lose their adhesion over time; i.e., the force to hold electronic components in a reflow oven is easily lost.
CITATION LIST
Patent Documents
Patent Document 1: JPH06-246482A
Patent Document 2: JP2008-062239A
Patent Document 3: JP2011-173173A
SUMMARY OF INVENTION
Technical Problem
[0005] An object of the present invention is to provide a soldering-flux-oriented novel base resin that enhances the fluidity of a soldering flux and both the visco-stability and adhesion of a solder paste, while improving the color tone and anti-crack property of the flux residue.
Solution to Problem
[0006] The present inventors conducted extensive research to achieve the above object, and accordingly found that a rosin containing specific resin acids in a specific proportion serves as a base resin that can achieve the object.
[0007] Specifically, the present invention relates to the following base resin for a soldering flux, the soldering flux, the solder paste, and the postflux.
[0000] Item 1. A base resin for a soldering flux, the base resin comprising a rosin (A) containing: at least 15 wt % of a pimarane-type resin acid (a-1); at least 1 wt % of a labdane-type resin acid (a-2); and at least 50 wt % of an abietane-type resin acid that has no conjugated double bond (a-3).
Item 2. The base resin for a soldering flux according to Item 1 wherein the component (A) has a Gardner color of 2 or less.
Item 3. A soldering flux comprising the base resin for a soldering flux according to Item 1 or 2, a flux solvent (B), and optionally an activator (C).
Item 4. The soldering flux according to Item 3 further comprising a thixotropic agent (D).
Item 5. A solder paste comprising the soldering flux according to Item 4 and a solder powder.
Item 6. A postflux comprising the soldering flux according to Item 3.
Advantageous Effects of Invention
[0008] The base resin according to the present invention enhances the fluidity of a soldering flux and both the visco-stability and adhesion of a solder paste. Further, the base resin excels in thermal stability, and improves the color tone and anti-crack property of the flux residue.
[0009] The soldering flux according to the present invention maintains its fluidity even after being stored at room temperature for a long period of time; thus, the solder paste becomes excellent in its visco-stability, adhesion, and soldering properties (wettability). Further, because the color tone of the flux residue left after soldering is excellent, the inspection procedure, for example, becomes easy and the cleaning procedure may be omitted. Moreover, because the flux is less crackable, problems associated with the electrical reliability of circuits, such as migration caused by water adhesion, are less likely to arise.
[0010] In addition, the solder paste according to the present invention is not only excellent in visco-stability over time and thus well-suited to long-term storage, but also excellent in adhesion. What is more, there is little change in visco-stability over time. The soldering properties (wettability) are also excellent, as are the color tone and crack resistance of the flux residue generated after soldering.
[0011] The rosin (A) according to the present invention is useful not only as a base resin for fluxes for solder pastes but also as a base resin for prefluxes, postfluxes (fluxes for dip soldering), and fluxes for rosin-containing solders, thread solders, and like solders. In particular, postfluxes containing the base resin according to the present invention have excellent stability over time and soldering properties. The color tone of the flux residue generated after soldering is also excellent.
DESCRIPTION OF EMBODIMENTS
[0012] The base resin for a soldering flux according to the present invention comprises a rosin (A) (hereinafter, referred to as “component (A)”) containing at least 15 wt % of a pimarane-type resin acid (a-1) (hereinafter, referred to as “component (a-1)”), at least 1 wt % of a labdane-type resin acid (a-2) “(hereinafter, referred to as component (a-2)”), and at least 50 wt % of an abietane-type resin acid that has no conjugated double bond (a-3) “(hereinafter, referred to as component (a-3)”).
[0013] A pimarane-type resin acid, i.e., component (a-1), refers to a resin acid that has a pimarane skeleton or an isopimarane skeleton, and specifically refers to a resin acid represented by the following formula (1)
[0000]
[0000] wherein X represents —CH 2 CH 3 or —CH═CH 2 ; and the dotted lines indicate that one of the bonds shown with the dotted lines may be a carbon-to-carbon double bond.
[0014] Examples of resin acids represented by formula (1) include pimaric acid, isopimaric acid, sandaracopimaric acid, and hydrogenated products thereof. Component (A) may contain a mixture of two or more such acids and hydrogenated products.
[0015] The labdane-type resin acid, i.e., component (a-2), refers to a resin acid that has a labdane skeleton, and specifically refers to a resin acid represented by the following formula (2)
[0000]
[0000] wherein Y represents —CH 2 CH═C(CH 3 )—CH═CH 2 , —CH 2 CH 2 —CH(CH 3 )—CH═CH 2 , —CH 2 CH 2 —CH(CH 3 )—CH 2 —CH 3 , —CH 2 CH═C(CH 3 )—CH 2 —CH 3 , —CH 2 CH 2 —CH(CO 3 )—CH 2 —COOH, or —CH 2 CH 2 —C(CH 3 )═CH—COOH. The dotted line indicates that the bond shown with the dotted line may be a carbon-to-carbon double bond.
[0016] Examples of resin acids represented by formula (2) include communic acid-derived resin acids, and agathic acid-derived resin acids. Examples of communic acid-derived resin acids include cis-communic acids, trans-communic acids, micro-communic acids, and hydrogenated products thereof. Examples of agathic acid-derived resin acids include agathic acids, dihydroagathic acids, and hydrogenated products thereof. Component (A) may contain a mixture of two or more such acids and hydrogenated products.
[0017] Component (a-3) refers to an abietane-type resin acid that has an abietane skeleton with no conjugated double bond intramolecularly. Examples of component (a-3) include dihydroabietic acid, dihydroabietic acid, and tetrahydroabietic acid. Component (A) may contain a mixture of two or more such acids.
[0018] Component (A) contains component (a-1) in an amount of at least 15 wt %, with about 15 to 25 wt % being preferable; component (A) contains component (a-2) in an amount of at least 1 wt %, with about 1 to 10 wt % being preferable; and component (A) contains component (a-3) in an amount of at least 50 wt %, with about 65 to 84 wt % being preferable. When component (A) contains each component in an amount below these numerical ranges, it may become difficult to bring about the advantageous effect of the present invention. Component (A) may contain one or more other resin acids in addition to components (a-1) to (a-3), and if it does so, component (A) contains the one or more other resin acids typically in an amount of less than 5 wt %. Component (A) preferably consists of only components (a-1) to (a-3).
[0019] Components (a-1) to (a-3) and other resin acids contained in component (A) can be quantified by various known analytical methods, such as gas chromatography.
[0020] The production method of component (A) is not particularly limited, and various known methods can be used. Specific examples include the following methods 1 to 3 described below.
[0000] 1. A method comprising: purifying a starting material rosin (e.g., gum rosin, wood rosin, tall oil rosin); and subjecting the purified product to a hydrogenation reaction and/or a disproportionation reaction to thereby produce component (A) containing a predetermined amount of components (a-1) to (a-3). In this method, it is preferable to use as a starting material rosin a rosin that contains some quantity of components (a-1) and (a-2), and such a rosin can be identified with reference to academic documents known at the time the present application was filed.
2. A method comprising: purifying a starting material rosin; subjecting the purified product to a hydrogenation reaction and/or a disproportionation reaction to thereby prepare a rosin containing a predetermined amount of component (a-3); and adding to the resulting rosin a predetermined amount of components (a-1) and (a-2), which are separately obtained or prepared through a known method, to thereby produce component (A). The starting material rosin may contain components (a-1) and (a-2) in advance.
3. A method comprising: mixing components (a-1) to (a-3), which are separately obtained or prepared through a known method, to thereby produce component (A).
4. A method comprising: adding components (a-1) to (a-3), which are separately obtained or prepared through a known method, to a starting material rosin; and mixing them to thereby produce component (A).
[0021] Commercially available products can be used as component (a-1), and component (a-1) can also be prepared through a method disclosed, for example, in J. Am. Chem. Soc. 70, 2079 (1948), J. Org. Chem. 23, 25-26 (1958), Can. J. Chem. 38 663-667 (1960).
[0022] Commercially available products can be used as component (a-2), and component (a-2) can also be prepared through a method disclosed, for example, in J. Am. Chem. Soc., 77, 2823 (1955), Weissman Holzforshung 28, 186-188 (1974), or JPS51-131899A.
[0023] Commercially available products can be used as component (a-3), and component (a-3) can also be prepared through a method disclosed, for example, in J. Org. Chem. 31, 4246-4248 (1966), J. Org. Chem. 31, 4128 (1966), J. Org. Chem. 34, 1550 (1969), or JPS51-149256A.
[0024] In the aforementioned purification step, various known techniques, such as distillation, extraction, and recrystallization, can be employed. Distillation, for example, can typically be performed at a temperature of about 200 to 300° C. under reduced pressure of about 0.01 to 3 kPa. In extraction, an alkaline aqueous solution of a starting material rosin is prepared, and the insoluble unsaponified product is extracted with any of various organic solvents, followed by neutralization of the aqueous layer. Examples of recrystallization include a technique in which a starting material rosin is dissolved in an organic solvent, i.e., a good solvent, and the solvent is distilled off to give a thick solution, followed by addition of an organic solvent, i.e., a poor solvent.
[0025] The aforementioned hydrogenation reaction can be carried out by various known methods. Specifically, a starting material rosin is subjected to a hydrogenation reaction in the presence of a hydrogenation catalyst. The reaction temperature is typically about 100 to 300° C., the hydrogen pressure is typically about 1 to 25 MPa, and the reaction time is typically about 1 to 10 hours. Examples of hydrogenation catalysts include: supported catalysts configured such that palladium, rhodium, ruthenium, platinum, and/or the like is carried on carbon, alumina, silica, silica alumina, zeolite, or the like; metal powders of nickel, platinum, or the like; and iodine and iodinated products such as iron iodides. The hydrogenation catalyst is used in an amount of typically about 0.01 to 10 wt % based on the amount of the starting material rosin.
[0026] The aforementioned disproportionation reaction can be carried out by using various known methods. Specifically, a starting material rosin is subjected to a disproportionation reaction in the presence of a disproportionation catalyst. The reaction temperature is typically about 100 to 300° C., and the reaction pressure is typically ordinary pressure, or less than 1 MPa. The aforementioned examples of hydrogenation catalysts can also be used as a disproportionation catalyst, and the disproportionation catalyst is used in an amount of typically about 0.01 to 10 wt % based on the amount of the starting material rosin.
[0027] The color tone of component (A) is not particularly limited, but the Gardner color thereof is preferably 2 or less, taking into consideration the over-time stability of the flux and solder paste, the color tone (transparency) of flux residue, and the like.
[0028] Component (A) is not particularly limited in terms of other physical properties, but the acid value (JIS K 5902), for example, is typically about 150 to 190 mgKOH/g, and the softening point (JIS K 5902) is typically about 70 to 90° C.
[0029] The flux according to the present invention is a composition containing a base resin according to the present invention (component (A)), a flux solvent (B) (hereinafter, referred to as component (B)), and optionally an activator (C) (hereinafter, referred to as component (C)).
[0030] For component (B), various known substances can be used without any particular restriction. Specific examples include ether alcohols, such as diethylene glycol monohexyl ether, diethylene glycol monobutyl ether, ethylene glycol monohexyl ether, and ethylene glycol monoethylhexyl ether; non-ether alcohols, such as 2-propanol, octanediol, benzyl alcohol, 1,3-butanediol, 1,4-butanediol, 2-(2-n-butoxyethoxy)ethanol, and terpineol; esters, such as isopropyl acetate, ethyl propionate, butyl benzoate, and diethyl adipate; hydrocarbons, such as n-hexane, dodecane, and tetradecene; and pyrrolidones, such as N-methyl-2-pyrrolidone. Among these substances, when using the flux for preparing a solder paste, the above ether alcohols having a high boiling point are preferable, taking into consideration the reflow temperature (typically 230 to 260° C.), and ether alcohols having a boiling point of about 230 to 260° C. are particularly preferable. When using the flux as a postflux, non-ether alcohols are preferable.
[0031] Examples of component (C) include monocarboxylic acids, such as palmitic acid, stearic acid, benzoic acid, and picolinic acid; dicarboxylic acids, such as succinic acid, adipic acid, glutaric acid, azelaic acid, sebacic acid, dodecanedioic acid, and direr acid; bromodiols, such as 1-bromo-2-butanol, 1-bromo-2-propanol, 3-bromo-1-propanol, 3-bromo-1,2-propanediol, 1,4-dibromo-2-butanol, 1,3-dibromo-2-propanol, 2,3-dibromo-1-propanol, 1,4-dibromo-2,3-butanediol, 2,3-dibromo-1,4-butenediol, 2,3-dibromo-2-butene-1,4-diol, and 2,2-bis(bromomethyl)-1,3-propanediol; hydrohalogenic acid salts of organic amines, such as ethylamine hydrobromide, diethylamine hydrobromide, and methylamine hydrobromide; bromoalkanes, such as 1,2,3,4-tetrabromobutane, and 1,2-dibromo-1-phenylethane; bromoalkenes, such as 1-bromo-3-methyl-1-butene, 1,4-dibromobutene, 1-bromo-1-propene, 2,3-dibromopropene, and 1,2-dibromostyrene; benzyl bromides, such as 4-stearoyloxybenzyl bromide, 4-stearyloxybenzyl bromide, 4-stearylbenzyl bromide, 4-bromomethylbenzyl stearate, 4-stearoylaminobenzyl bromide, 2,4-bisbromomethylbenzyl stearate, 4-palmitoyloxybenzyl bromide, 4-myristoyloxybenzyl bromide, 4-lauroyloxybenzyl bromide, and 4-undecanoyloxybenzyl bromide; polyamines, such as N,N′-bis(4-aminobutyl)-1,2-ethanediamine, triethylenetetramine, N,N′-(3-aminopropyl)ethylenediamine, and N,N′-bis(3-aminopropyl)piperazine; and chlorine-containing activators, such as diethylamine hydrochloride. These substances may be used singly or in combination of two or more.
[0032] The flux according to the present invention may further optionally comprise a thixotropic agent (D) (hereinafter, referred to as “component (D)”), a base resin (E) other than component (A) (hereinafter, referred to as “component (E)”), or an additive (hereinafter, referred to as “component (F)”).
[0033] When using the flux according to the present invention to prepare a solder paste, component (D) is preferably used for the purpose of adjusting the suitability for screen printing. Specific examples of component (D) include: thixotropic agents of animal or vegetable origin, such as castor oil, hydrogenated castor oil, bees wax, and carnauba wax; and amide-based thixotropic agents, such as stearamide, and 12-hydroxystearic acid ethylenebisamide. These substances may be used singly or in combination of two or more.
[0034] Examples of component (E) include: rosin-based resins other than component (A), such as the aforementioned starting material rosins, purified products thereof (purified rosins), disproportionated rosins made from these rosins, hydrogenated rosins made from these rosins, formylated rosins made from these rosins; and polymerized rosins made from these rosins; and synthetic resins, such as epoxy resins, acrylic resins, polyimide resins, polyamide resins (nylon resins), polyester resins, polyacrylonitrile resins, vinyl chloride resins, polyvinyl acetate resins, polyolefin resins, fluorine-based resins, and ABS resins.
[0035] Examples of component (F) include additives, such as antioxidants, antifungal agents, and delusterants.
[0036] The amount of each component to be contained in the flux is suitably determined in accordance with the utility form of the flux. The amount of each component of the flux used for preparing a solder paste is, for example, as follows:
[0000] Component (A): about 20 to 60 wt %, preferably 30 to 60 wt %
Component (B): about 60 to 20 wt %, preferably 55 to 30 wt %
Component (C): about 0 to 20 wt %, preferably 1 to 10 wt %
Component (D): about 0 to 20 wt %, preferably 1 to 10 wt %
Component (E): about 0 to 20 wt %, preferably 0 to 10 wt %
Component (F): about 0 to 10 wt %, preferably 1 to 5 wt %
[0037] The amount of each component of the flux used for preparing a postflux is, for example, as follows:
[0000] Component (A): about 20 to 60 wt %, preferably 25 to 50 wt %
Component (B): about 80 to 40 wt %, preferably 70 to 45 wt %
Component (C): about 0 to 10 wt %, preferably 1 to 5 wt %
Component (E): about 0 to 10 wt %, preferably 0 to 5 wt %
Component (F): about 0 to 10 wt %, preferably 1 to 5 wt %
[0038] The flux according to the present invention can be used without any treatment, or diluted with a solvent, such as isopropyl alcohol and benzyl alcohol, for use as a postflux or dip soldering flux. Moreover, the flux can be mixed with any of various lead-free solder alloy powders for use as a lead-free solder paste, and also used for various thread solders.
[0039] The solder paste according to the present invention comprises the flux according to the present invention and a solder powder. The amount of each component is not particularly limited, but the flux is contained typically in an amount of about 5 to 20 wt %, and the solder powder is contained typically in an amount of about 80 to 95 wt %. The solder paste can be prepared in accordance with various known procedures (e.g., planetary mill).
[0040] Examples of solder powders include: conventionally used lead eutectic solder powders, such as Sn—Pb-based solder powders; and lead-free solder powders, such as Sn solder powders, Sn—Ag-based solder powders, Sn—Cu-based solder powders, Sn—Zn-based solder powders, Sn—Sb-based solder powders, Sn—Ag—Cu-based solder powders, Sn—Ag—Bi-based solder powders, Sn—Ag—Cu—Bi-based solder powders, Sn—Ag—Cu—In-based solder powders, Sn—Ag—Cu—S-based solder powders, and Sn—Ag—Cu—Ni—Ge-based solder powders. The solder powders typically have, but are not particularly limited to, an average primary particle diameter of about 1 to 50 μm, with about 20 to 40 μm being preferable.
EXAMPLES
[0041] Hereinafter, Examples and Comparative Examples describe the present invention in detail. However, the scope of the present invention is, needless to say, not limited to the Examples. The symbols “parts” and “%” are based on weight.
[0042] The compositional ratios of resin acids shown in Tables 1 and 2 were determined by measurement using a commercially available gas chromatograph mass spectrometer (manufactured by Agilent Technologies, trade name “Agilent 6890” and “Agilent 5973N”). A commercially available column (manufactured by Shinwa Chemical Industries Ltd., trade name “Advance-DS”) was used.
Preparation of Rosin (A)
Production Example 1
[0043] 185 g of Argentine gum rosin (indicated as “Starting Material 1” in Table 1; Table 1 shows the starting materials of the following Examples in the same manner) was placed in a reduced-pressure distillation vessel, and distilled at a reduced pressure of 0.4 kPa in a nitrogen atmosphere, thereby giving a purified rosin. Subsequently, 150 g of the purified rosin and 0.7 g of 5% palladium on carbon (water content: 50%) were placed in a 0.3-L rotary autoclave, and the oxygen in the system was removed, followed by pressurization to 10 MPa with hydrogen. The temperature was raised to 220° C., and at the same temperature a hydrogenation reaction was carried out for 3 hours, thereby giving rosin (A1). Table 1 shows the compositional ratios of the resin acids contained in the starting material rosin (Starting Material 1) and Table 2 shows the compositional ratios of the resin acids contained in rosin (A1) and the physical properties of rosin (A1) (Tables 1 and 2 also show the compositional ratios of the resin acids contained in the starting material rosins and the compositional ratios and physical properties of the obtained rosins of the following Examples).
Production Example 2
[0044] The procedure described in Production Example 1 was repeated except that Indonesian gum rosin (Starting Material 2) was used as a starting material rosin, thereby giving rosin (A2).
Production Example 3
[0045] The procedure described in Production Example 1 was repeated except that gum rosin from the Guangxi Province of China (Starting Material 3) was used as a starting material rosin, thereby giving rosin (A3).
Production Example 4
[0046] The procedure described in Production Example 1 was repeated except that a 1:1 mixture (ratio by weight) of Argentine gum rosin, which was the same as that used in Production Example 1 (Starting Material 1), and gum rosin from the Yunnan Province of China (Starting Material 4) was used as a starting material rosin, thereby giving rosin (A4).
Production Example 5
[0047] 250 g of Argentine gum rosin, which was the same as that used in Production Example 1 (Starting Material 1), was placed in a reduced-pressure distillation vessel, and distilled at a reduced pressure of 0.4 kPa in a nitrogen atmosphere, thereby giving a purified rosin. Subsequently, 200 g of the purified rosin and 0.4 g of 5% palladium on carbon (water content: 50%) were placed in a 0.5-L flask, and the temperature was raised to 260° C. in a nitrogen atmosphere. At the same temperature, a disproportionation reaction was carried out for 3 hours, thereby giving rosin (A5).
Comparative Production Example 1
[0048] The procedure described in Production Example 1 was repeated except that gum rosin from the Yunnan Province of China, which was the same as that used in Production Example 4 (Starting Material 4), was used as a starting material rosin, thereby giving rosin (P1).
Comparative Production Example 2
[0049] Argentine gum rosin, which was the same as that used in Production Example 1 (Starting Material 1), was placed in a reduced-pressure distillation vessel, and distilled at a reduced pressure of 0.4 kPa in a nitrogen atmosphere, thereby giving rosin (P2).
Comparative Production Example 3
[0050] 250 g of gum rosin from the Yunnan Province of China, which was the same as that used in Production Example 4 (Starting Material 4), was placed in a reduced-pressure distillation vessel, and distilled at a reduced pressure of 0.4 kPa in a nitrogen atmosphere, thereby giving a purified rosin. 200 g of the resulting purified rosin and 0.08 g of 3.5% palladium on carbon (water content: 50%) were placed in a 0.5-L flask, and the temperature was raised to 280° C. in a nitrogen atmosphere. At the same temperature, a disproportionation reaction was carried out for 3 hours, thereby giving rosin (P3).
Comparative Production Example 4
[0051] 250 g of a commercially available, Chinese hydrogenerated rosin (manufactured by Arakawa Chemical Industries, Ltd., trade name “Hypale CH,” Starting Material 5) was placed in a reduced-pressure distillation vessel, and distilled at a reduced pressure of 0.4 kPa in a nitrogen atmosphere, thereby giving a purified hydrogenerated rosin. 200 g of the resulting purified hydrogenerated rosin and 0.06 g of 5% palladium on carbon (water content: 50%) were placed in a 0.5-L flask, and the temperature was raised to 260° C. in a nitrogen atmosphere. At the same temperature, a disproportionation reaction was carried out for 1 hour, thereby giving rosin (P4).
Examples 1 to 5 and Comparative Examples 1 to 4
Production of Flux for Solder Paste and Solder Paste
[0052] 50 parts of component (A1) obtained in Production Example 1, 5 parts of 12-hydroxystearic acid ethylenebisamide, and 45 parts of diethylene glycol monohexyl ether were placed in a beaker, and heated while stirring to melt them, thereby preparing a flux for solder paste. Subsequently, 10 parts of the flux was mixed with 90 parts of a lead-free solder powder (Sn—Ag—Cu alloy; 96.5 wt %/3 wt %/0.5 wt %; average particle diameter: 25 to 38 μm) while stirring, thereby preparing a solder paste. The same procedure was repeated using the rosins obtained in Production Examples 2 to 5 and Comparative Production Examples 1 to 4 to prepare fluxes for solder paste and solder pastes.
Comparative Example 5
[0053] The procedure described in Example 1 was repeated except that Hypale CH (Starting Material 5, indicated as (P5) in Table 3) was used in place of component (A1), thereby preparing a flux for solder paste and a solder paste.
Test on Flux for Solder Paste
Stability Over Time
[0054] The fluxes for solder paste prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were stored at room temperature for 1 month, and evaluated for their fluidity in accordance with the following criteria. Table 3 shows the results.
[0000] 1: Flowing at room temperature
2: Not flowing at room temperature, but soft and easy to stir
3: Solid at room temperature and difficult to stir
Test on Solder Paste
Stability Over Time
[0055] The solder pastes prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were stored at a temperature of 40° C. for 7 days. Thereafter, the viscosity was measured with a PCU-205 automatic viscometer (manufactured by Malcolm Co., Ltd.), and the change in viscosity from the point at which the pastes were prepared (day 0) was examined. The smaller the change in viscosity, the better the stability over time. Table 3 shows the results.
[0000] 1. Viscosity change: less than 20 Pa·S
2. Viscosity change: 20 Pa·S or more and less than 40 Pa·S
3. Viscosity change: 40 Pa·S or more
Adhesion
[0056] The solder pastes prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were individually printed on a copper plate, and the adhesion was measured by a TK-1 tackiness tester (manufactured by Malcolm Co., Ltd.). The larger the value, the better the adhesion. Table 3 shows the results.
[0000] 1: Observed value: 80 gf or more
2: Observed value: 30 gf or more to less than 80 gf
3: Observed value: less than 30 gf
Soldering Properties
[0057] The solder pastes prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were evaluated for soldering properties (wettability) in accordance with JIS Z3284, Appendix 10, regarding a wettability and dewetting test. All of the solder pastes showed excellent soldering properties (spreading scale 1 or 2; the results are not shown in Table 3).
Color Tone of Flux Residue
[0058] The solder pastes prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were individually printed on a copper substrate, and the soldered portions were observed with a VW-6000 microscope (manufactured by Keyence Corporation: 30× power) to determine the color tone of the flux residues in accordance with the following criteria.
[0000] 1: Clear and colorless
2: Slightly colored
3: Colored
Cracks in Flux Residue
[0059] Together with the color tone evaluation of the flux residues, the presence of cracks was also examined. None of the solder pastes prepared in Examples 1 to 5 and Comparative Examples 1 to 5 had cracks (the results are not shown in Table 3).
Examples 6 to 10 and Comparative Examples 6 to 9
Production of Postflux
[0060] 50 parts of component (A1) obtained in Production Example 1 and 50 parts of isopropyl alcohol were placed in a beaker, and heated while stirring to melt them, thereby preparing a postflux. The same procedure was repeated using the rosins obtained in Production Examples 2 to 5 and Comparative Production Examples 1 to 4, thereby preparing postfluxes.
Comparative Example 10
[0061] The procedure described in Example 6 was repeated except that Hypale CH (Starting Material 5, indicated as (P5) in Table 4) was used in place of component (A1), thereby preparing a postflux.
Test on Postflux
Stability Over Time
[0062] The postfluxes prepared in Examples 6 to 10 and Comparative Examples 6 to 10 were stored at room temperature for one week, and evaluated for precipitate formation in accordance with the following criteria. The less the precipitate, the better the stability over time. Table 4 shows the results.
[0000] 1. No precipitate was formed
2. A small amount of precipitate was formed
3. A significant amount of precipitate was formed
Soldering Properties
[0063] The postfluxes prepared in Examples 6 to 10 and Comparative Examples 6 to 10 were evaluated for soldering properties (wettability) in accordance with JiS Z3197 regarding a solder spreading method, and the spread factor was calculated. The larger the value, the better the soldering properties. Table 4 shows the results.
[0000] 1. Spreading factor: 65% or more
2. Spreading factor: less than 65%
Color Tone of Flux Residue
[0064] The soldered portions were observed with a VW-6000 microscope (manufactured by Keyence Corporation: 30× power) to determine the color tone of the flux residues in accordance with the following criteria.
[0000] 1. Clear and colorless
2. Slightly colored
3. Colored
[0065]
[0000]
TABLE 1
Starting
Starting
Starting
Starting
Starting
Starting Material Resin
Material 1
Material 2
Material 3
Material 4
Material 5
Component (a-1)
23%
21%
18%
9%
11%
Component
Communic Acid—
3%
0%
3%
0%
0%
(a-2)
derived Resin Acid
Agathic Acid—
0%
9%
0%
0%
0%
derived Resin Acid
Component
Dehydroabietic Acid
5%
2%
3%
3%
10%
(a-3)
Dihydroabietic Acid
0%
0%
0%
0%
61%
Tetrahydroabietic
0%
0%
0%
0%
18%
Acid
Other Resin Acid
69%
68%
76%
88%
0%
[0000]
TABLE 2
Comp.
Comp.
Comp.
Comp.
Production
Production
Production
Production
Production
Production
Production
Production
Production
Example 1
Example 2
Example 3
Example 4
Example 5
Example 1
Example 2
Example 3
Example 4
Obtained Resin
(A1)
(A2)
(A3)
(A4)
(A5)
(P1)
(P2)
(P3)
(P4)
(a-1)
23%
21%
18%
17%
20%
9%
22%
9%
10%
(a-2)
Communic Acid—
3%
0%
3%
2%
3%
0%
3%
0%
0%
derived Resin Acid
Agathic Acid—
0%
9%
0%
0%
0%
0%
0%
0%
0%
dervived Resin Acid
(a-3)
Dehydroabietic
21%
20%
16%
28%
41%
33%
5%
59%
28%
Acid
Dihydroabietic
36%
31%
32%
33%
34%
30%
0%
31%
38%
Acid
Tetrahydroabietic
17%
19%
31%
20%
2%
28%
0%
1%
24%
Acid
Other Resin Acid
0%
0%
0%
0%
0%
0%
70%
0%
0%
Physical
Gardner Color
1−
1−
1−
1−
1+
1−
3
1
1−
Properties
Acid Value
169
183
170
167
171
168
171
175
169
(mgKOH/g)
Softening
77
81
78
79
83
78
80
85
77
Point (° C.)
[0000]
TABLE 3
Comp.
Comp.
Comp.
Comp.
Comp.
Example 1
Example 2
Example 3
Example 4
Example 5
Example 1
Example 2
Example 3
Example 4
Example 5
Base Resin
(A1)
(A2)
(A3)
(A4)
(A5)
(P1)
(P2)
(P3)
(P4)
(P5)
Starting
Material 5
Over-time Stability
1
1
1
1
1
2
1
3
3
2
of Flux for Solder
Paste
Over-time Stability
1
1
1
1
1
3
2
3
3
2
of Solder Paste
Adhesion of Solder
1
1
1
1
1
3
2
3
3
2
Paste
Color of Flux
1
1
1
1
1
1
2
1
1
3
Residue
[0000]
TABLE 4
Comp.
Comp.
Comp.
Comp.
Comp.
Example 6
Example 7
Example 8
Example 9
Example 10
Example 6
Example 7
Example 8
Example 9
Example 10
Base Resin
(A1)
(A2)
(A3)
(A4)
(A5)
(P1)
(P2)
(P3)
(P4)
(P5)
Starting
Material 5
Overtime Stability
1
1
1
1
1
2
1
3
3
2
of Postflux
Soldering Properties
1
1
1
1
1
1
1
1
2
1
Color of Flux
1
1
1
1
1
1
2
1
1
3
Residue
[0066] The amounts of resin acids (%=wt %) shown in Tables 1 and 2 are values rounded off to the whole number except for the case where the value is 0%. 0% means that the amount was below measurable limits.
[0067] The results of Examples 1 to 5 revealed that the fluxes for solder paste containing component (A) as a base resin were excellent in stability over time, and the solder pastes containing such fluxes were also excellent in visco-stability over time and adhesion. The solder pastes also had excellent soldering properties (wettability), and the color tone and crack resistance of the flux residues were excellent as well.
[0068] In contrast, the results of Comparative Examples 1 and 3 to 5 revealed that despite containing component (a-3) in an amount of 50 wt % or more, when the base resins contained component (a-1) in an amount of less than 15 wt % and no component (a-2), the fluxes were poor in stability over time, and the solder pastes were poor in visco-stability and adhesion. Further, the color tone of the flux residue was not excellent in Comparative Example 5.
[0069] The results of Comparative Example 2 revealed that despite containing a predetermined amount of components (a-1) and (a-2), when the base resin contained component (a-3) in an amount below the predetermined amount, the solder paste was poor in visco-stability and adhesion, and the color tone was not excellent.
[0070] The results of Examples 6 to 10 revealed that the postfluxes containing component (A) as a base resin were excellent in stability over time. Further, the postfluxes, when used, showed excellent soldering properties (wettability), and the color tone of the flux residues was excellent.
[0071] In contrast, the results of Comparative Examples 6 and 8 to 10 revealed that despite containing component (a-3) in an amount of 50 wt % or more, when the base resins contained component (a-1) in an amount of less than 15 wt % and no component (a-2), the postfluxes were poor in stability over time. Further, the soldering properties (wettability) in Comparative Example 9 were poor, and the color tone of the flux residue in Comparative Example 10 was also poor.
[0072] Comparative Example 7 revealed that despite containing a predetermined amount of components (a-1) and (a-2), when the base resin contained component (a-3) in an amount below the predetermined amount, the color tone of the flux residue was poor. | The object of the present invention is to provide a soldering-flux-oriented novel base resin that enhances the fluidity of a soldering flux and both the visco-stability and adhesion of a solder paste, while improving the color tone and anti-crack property of the flux residue. The present invention is directed to a base resin for a soldering flux, the base resin comprising a rosin (A) containing at least 15 wt % of a pimarane-type resin acid (a-1), at least 1 wt % of a labdane-type resin acid (a-2), and at least 50 wt % of an abietane-type resin acid that has no conjugated double bond (a-3). | 1 |
The invention relates to methods of preparing esters of rosin and more particularly relates to the preparation of polyol esters of tall oil rosin.
BACKGROUND OF THE INVENTION
The prior art is replete with descriptions of methods for preparing polyol esters of rosin. Representative of such descriptions are those found in the U.S. Pat. Nos. 2,369,125; 2,729,660; 3,780,012; 3,780,013; 4,548,746; and 4,585,584.
The method of the present invention is an improvement over prior art methods in that it employs an esterification catalyst giving a product of improved hot-melt stability.
SUMMARY OF THE INVENTION
A novel method of preparing a polyol ester of a rosin is disclosed which comprises esterifying the rosin with the polyol in the presence of a catalytic proportion of an organic ester of hypophosphorous acid.
The polyol ester of rosin made in accordance with the method of the invention are useful as tackifier ingredients in hot-melt adhesive compositions such as EVAC hot-melt adhesives.
DETAILED DESCRIPTION OF THE INVENTION
The rosins which may be esterified by the method of the invention are well known compounds as are methods of their preparation. Rosin is mainly a mixture of C 20 , fused-ring, monocarboxylic acids, typified by levopimaric and abietic acids. The rosins include gum rosin, wood rosin and tall oil rosin. The method of the invention is particularly advantageous when applied to esterification of tall oil rosin. The rosin may be hydrogenated, disproportionated or polymerized rosin as well as crude, untreated rosin.
The polyols employed in the method of the invention are also well known and are represented by diols such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylene glycol; triols such as glycerol; tetrols such as pentaerythritol; hexols such as mannitol and sorbitol and like polyols. The method of the invention is particularly advantageous when the polyol selected is pentaerythritol.
The esterfication of the invention is carried out in the presence of a catalytic proportion of an organic ester of hypophosphorous acid. A catalytic proportion is generally within the range of from about 0.02 to 1.0 percent by weight of the rosin and preferably 0.1 to 0.5 percent.
Organic esters of hypophosphorous acid are well known and are represented for example by aliphatic esters such as 2-ethylhexyl phosphinic acid and the like; aromatic esters such as benzene phosphinic acid and the like.
Esterification is advantageously carried out by bringing together the rosin and an equivalent excess of the polyol (up to 20 percent excess) in an appropriate reaction vessel and heating the mixture to a temperature within the range of from about 150° C. to 300° C., preferably 180° C. to 280° C.
Esterification may be carried out under a broad range of pressure conditions including sub-, super- and atmospheric pressures. Advantageously, atmospheric pressures are employed.
Advantageously, the esterification reaction can be accomplished in the presence of an inert atmosphere, such as a nitrogen gas atmosphere provided by a nitrogen purge of the reaction vessel prior to addition of the reactants and a nitrogen sparge during the reaction. Since light color is a desirable property of the rosin ester and the color is sensitive to oxygen exposure, oxygen exposure is preferably minimized.
Progress of the esterification may be followed by conventional analysis of the reaction mixture to determine the acid number. The esterification may be terminated to any desired acid number. In general, the reaction is accepted as sufficiently complete when the acid number drops to 15 or lower.
The following examples describe the manner and the process of making and using the invention and set forth the best mode of carrying out the invention but are not to be considered as limiting the invention.
The softening points (sp) were determined by the Ball and Ring method of ASTM test method 28-58T.
EXAMPLE 1
To a suitable reaction vessel equipped with a stirrer and thermometer were added 100 parts of disproportionated rosin having a color of 4 Gardner. Next there was added 11 parts of pentaerythritol and 0.25% benzene phosphinic acid as the catalyst, based on the weight of the rosin. The mixture was heated to 275° C. for 51/2 hours. The resultant rosin ester had a color of 5 Gardner, an acid number of 7 and a sp of 99° C.
Hot-melt adhesives were made up and then tested by heating to 175° C. in a forced air oven and observing the percentage of skinning which occurred over periods of time and the degree of viscosity change. The test results are given in the Table 1, below for the product of Example 1 and a comparative product made with lithium carbonate.
TABLE 1______________________________________Hot Melt PropertiesColor G Skinning, % ViscosityExample Initial Final 24 hr 48 hr 96 hr Change, %______________________________________1 4- 8 0 0 0 +16Lithium 5- 12 35 50 70 -20Carbonate______________________________________ | Organic esters of hypophosphorous acid are used to catalyze the esterification of rosin with a polyol. The method is an improvement in that reaction time is shortened and the ester product exhibits improved heat stability. | 2 |
[0001] This invention relates to geographic displays, and more particularly to a world globe with an accessory detailed display of a selected region of the globe.
BACKGROUND OF THE INVENTION
[0002] Spherical globes that have imprinted on their surface the map of the world are well known. They are generally provided with an axle through their north and south poles. They may be mounted on a base by the axle, so that they may be rotated for viewing a selected area U.S. Pat. No. 6,625,086 issued Sep. 23, 2003 to Kim discloses a globe with a rotation sensor on the axle. A pointer indicates a longitude position at a particular time zone on the globe. The sensor feeds the rotation information into an electronic processor and a display indicates a major city in that time zone and also displays the current time in that time zone.
[0003] Navigational aids for providing maps in vehicles and on computers have detailed maps stored on a memory such as a computer disc. The information is retrieved by inputting some location data. This enables selection of particular map information from the memory to be displayed on a computer monitor or a small monitor, such as a battery operated liquid crystal display in a vehicle.
[0004] Globes can be imprinted with a great deal of geographic information. However, unless the world globe is very large, the details are not easily read. Because a globe is spherical, it is awkward and expensive to have a large one. It is much less awkward and costly to have detailed planar maps. They may also be more easily updated. Flat and folded maps are very useful, but they lack the perspective given by the globe.
SUMMARY OF THE INVENTION
[0005] It is accordingly an object of the invention to provide a world globe with geographic features thereon that rotates on an axle through the north and south poles with the axle mounted on a base. The globe is not large enough to legibly carry all of the geographic and map information that the invention provides. Additional detailed information of a selected area of the globe is provided on a display attached to the globe either on the base or at another location. Detailed information, much more than can be imprinted even on a large globe, is stored on a memory such as, but not limited to, a compact disc. Input to the memory to select a detailed map of a particular area of the globe to be displayed on the display is provided by a longitudinal signal and a latitudinal signal. A rotary position sensor adapted to sense the rotary position of the globe on the rotational axis through the north and south poles provides an east/west longitude signal. An indicator such as a transparent pointer or reticle is provided adjacent the globe surface. Mounting means for the indicator provides for relative motion between the globe and the indicator along a north/south meridian in an arc concentric with the globe, thereby maintaining its position adjacent the globe surface. A second sensor detecting the north/south location of the indicator provides the latitude signal. The two signals enable the system to select the appropriate detailed map of that latitude and longitude from the memory and to enable it to be displayed on the display. Another feature may enable the display of a more or less magnified map if desired.
[0006] These and other objects, features, and advantages of the invention will become more apparent when the detailed description is studied in conjunction with the drawings in which like elements are designated by like reference characters in the various drawing figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a front elevation view of the invention.
[0008] FIG. 2 is schematic representation of the invention.
[0009] FIG. 3 is a front elevation view of another embodiment of the invention.
[0010] FIG. 4 is front elevation view of the embodiment of FIG. 3 with the display panel removed.
[0011] FIG. 5 is a side elevation view of another embodiment of the invention.
[0012] FIG. 6 is a front elevation view of another embodiment of the invention.
[0013] FIG. 7 is a front elevation view of another embodiment of the invention.
[0014] FIG. 8 is a sectional view through line 8 - 8 of FIG. 7 .
[0015] FIG. 9 is a sectional view taken through line 9 - 9 of FIG. 8 .
[0016] FIG. 10 is a sectional view through line 10 - 10 of FIG. 9 .
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0017] Referring now to the drawing FIGS. 1-2 , a globe 18 of the invention includes a sphere 4 imprinted with geographic indicia 17 representing earth on its surface. The sphere is supported on an axle element 2 that is attached to support base 1 . The sphere rotates about an axis 3 through the north pole 6 and the south pole 7 . A meridian member 5 extends between the two poles. An indicator 8 such as an arrow pointer is slidably mounted on the meridian member for north/south motion of the tip of the indicator on the sphere. By rotation of the sphere in the east/west direction and motion of the indicator in the north/south direction, a particular area of the earth is located. A signal 13 from a first sensor 10 sensing rotation of the sphere and therefor longitude information, and a signal 14 from the second sensor 11 sensing sliding position of the indicator and therefor latitude information of the selected area are fed to control circuit 19 . Circuit 19 selects a particular portion of the memory 12 corresponding to the selected area That detailed map information 16 is displayed on the display 15 . The memory 12 may be any of the memory media well known in the art. It may be easily replaced with updated information, or with another language. Control buttons 20 and 21 select low and high magnification map displays. Button 22 moves the display to an area east, and button 23 moves the display to an area west. Button 25 moves to an area north, and button 26 moves to an area south. These functions are well known in the vehicle navigation and computer map display art. Button 24 displays the current time at the selected area. An internal clock 29 is set by positioning the indicator 8 at a location where the time is known, then entering the correct time using the hour button 27 and minute button 28 . When moved to a different time zone, the system displays the time corrected to that time zone. Electric power is supplied through power cord 30 .
[0018] Referring now to FIGS. 3 and 4 , another embodiment 18 of the invention is shown in which the display panel 15 ′ is mounted on the base 1 ′ to display a detailed map 16 ′ and the time 31 at the location indicated by the cross hairs of the reticle 8 ′. The sphere 4 ′ imprinted with geographic information 17 ′ is mounted on an axle element 2 ′ at the south pole with a pivot 32 at the north pole. The sphere and axle rotate together. The axle is rotatably supported by the two bearings 33 within the base. A rotary position first sensor 10 ′ sends a signal through wire 13 ′ to the computer circuit 19 ′ indicating the longitudinal position of the reticle. A meridian member 5 ′ encircles the sphere and supports the pivot 32 . The reticle is mounted on a circular element 34 that is concentric with meridian member 5 ′ and that slides within a track on member 5 ′. A second sensor 11 ′ engages the element 34 and rotates when reticle and element 34 move, sending a signal representative of the latitude of the reticle through wire 14 ′ to the circuit 19 ′. The circuit 19 ′ selects from the memory 12 ′ a particular detailed map 16 ′ of the selected area for display on the display 15 ′. A clock circuit 29 ′ provides time for time display 31 . Electric power is provided by battery 35 .
[0019] Referring now to FIG. 5 , another embodiment 18 ″ of the invention is shown in which an arcuate support 36 is affixed to a base 37 . The display panel 38 is mounted on top of arcuate support 36 . The axle 40 of globe 39 is rotatably mounted on arcuate support 36 with rotary position sensor 41 sensing longitude information supplied to the control circuit 42 in the base. Rods 43 affixed to the base support a pivot 44 positioned in line with the center of the sphere. An indicator 45 positioned at the surface of the sphere is pivotally connected to the pivot 44 so that the indicator is maintained at the sphere surface as it moves in an arc concentric with the sphere along a meridian from south to north. Rotary position sensor 45 provides a signal indicative of the latitude position of the indicator to the control circuit. The control circuit selects from the memory a detail map of the area beneath the indicator to display on the display. Alternatively, the display may not be attached to the assembly, and may take the form of a video projector, a computer, and the like (not shown).
[0020] Referring now to FIG. 6 , another embodiment 18 ′″ of the invention is shown. Extending upward from the base 47 is a support element 48 . Pivots 49 support a ring member 50 that encircles globe 51 . At a first location 52 on ring member 50 a pivot 53 supports a first end 54 of the axle element 55 , and at a second location 56 on member 50 a second pivot 57 supports a second end 58 of the axle element The axle element may be comprised of two aligned segments. A rotary sensor 59 provides a signal related to the rotation of the globe about its axis, longitude data. An indicator 60 in the form of a light beam from a light emitting diode 63 is focused on the globe surface. Diode 63 is affixed at the end of a rigid rod 61 extending upward from the base. A rotary sensor 62 senses the rotary position of the ring member as the globe is moved under the indicator along a north south meridian for latitude data. The signals from the two sensors are applied as in the earlier embodiments. The display 64 may comprise a printer.
[0021] Referring now to FIGS. 7-10 another embodiment of the invention is shown in which the latitude and longitude sensing is entirely within the globe. And, when the globe transmits some light through its walls, even the indicator selecting a particular location on the globe may be contained within the globe. With this embodiment, the user may rotate the globe on its axis and swivel the axis on pivots to move a light spot emanating from within the globe to a desired location on the globe. That area will then be displayed in detail on the video display. This embodiment uses digital optical sensing, but other angular sensing means well known in the art may be used as well.
[0022] A globe 65 may be made of a light transmitting material such as plastic. It rotates about an axle 66 passing through the north and south poles. Rotary bearings 67 hold the globe in place on the axle while permitting free rotation of the globe. The axle is fixed on the ring 68 . The ring 68 swivels on pivots 69 that are affixed to the arcuate support member 70 that is mounted on the base 71 . The pivots are positioned so as to be at the equator of the globe. The mechanisms for providing latitude and longitude information as well as the indicator light beam are all within the globe are best seen in FIGS. 8-10 . A clear transparent disc 72 is affixed to the inside surface 77 of globe 65 by tabs 76 . Nine rows of opaque marks 73 with progressively increasing numbers of marks having 256 in the outermost row on the disc 72 are provided for binary signal angle detection in a manner well known in the art. The marks are not complete on the drawing. A bar 75 affixed to axle 66 has nine photo detectors 74 . These sense when a mark or a space between marks is at the detector. The result of the information from the detectors indicates the rotary position of the globe relative to the base (or longitude) to one five hundred and twelfth of a circle. This longitude information signal is passed to electronics (not shown) in the base and the detail information is displayed at monitor 79 .
[0023] Affixed to the axle vertically is a similarly marked second transparent disc 78 (marks not shown) for deriving latitude information. An equatorial pivot bar 83 is affixed at right angles to the axle at the equator of the globe. A sensing bar 80 rotates freely on the pivot bar 83 . It is provided with a row of photo detectors 81 to sense the presence or absence of marks on the disc. A weight 84 at the end of bar 80 ensures that the bar will remain vertical when the axle is tilted on pivots 69 . The disc 75 is preferably located at below 70 degrees south latitude. Because there is little detail to be displayed in the antarctic, details of that area will not generally be useful. The latitude signal from the sensors is transmitted by wire to electronics in the base as for the longitude information. The latitude and longitude signals may be transmitted wirelessly if desired. A beam of light 86 may be provided by laser light emitter 87 on the side of bar 80 to fall on the globe at the site selected by the user. The interior of the globe is lighted by a number of light emitting diodes 88 to enable the detectors to read the marks on the discs and to illuminate the globe for enhanced viewing.
[0024] While I have shown and described the preferred embodiments of my invention, it will be understood that the invention may be embodied otherwise than as herein specifically illustrated or described, and that certain changes in form and arrangement of parts and the specific manner of practicing the invention may be made within the underlying idea or principles of the invention | A spherical world globe ( 4 ) with geographic features imprinted on its surface rotates on an axis ( 2 ) through the poles. The sphere is not large enough to carry legible details of all areas. Greater details are stored in a memory ( 12 ′) such as a compact disc. An indicator ( 8 ) on the sphere is positionable north and south or the sphere is positionable relative to a fixed indicator to position the indicator along a north/south meridian. A sensor ( 11 ′) senses the north/south position of the indicator and sends a signal to a control circuit ( 19 ) connected to the memory. Another sensor ( 10 ′) connected to the rotation of the sphere sends an east/west signal to the control circuit. Using the two signals, the circuit finds the area corresponding to the area selected on the sphere in the memory and displays it on a display in greater detail than is visible on the sphere. | 6 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method and a device for controlling the heating of glow plugs in a diesel engine as are used to bring the glow plugs to a predetermined set point temperature at which the engine can be started.
2. Description of Related Art
The publication MTZ 10/2000 “Das elektronisch gesteuerte Glühsystem ISS für Dieselmotoren” [The electronically controlled ISS glow system for diesel engines] discloses a method for controlling the heating of glow plugs in a diesel engine. The glow command or glow requirement is issued after engine control initialization has been completed and after the temperature of the engine elements has been determined by way of the engine control system and subsequent successful establishment of communication between the engine control system and the glow control device.
For controlling the heating of the glow plugs of a diesel engine, it is important to know the thermal state of the glow plugs, fast-start glow plugs, in particular, for example, the residual temperature of the glow plugs after previous heating during repeated start and to include it in the following control. The thermal state of the glow plugs can be implemented to date however in the glow plug control system only from experiential values. To consider the residual temperature of the glow plug, knowledge of the entire history is necessary, requiring non-volatile memories and a time basis, in case data have to be included prior to resetting.
Measuring the glow plug temperature via the glow plug resistance is eliminated as a possibility of determining the glow plug temperature based on tolerances of the glow plugs with respect to their resistance course because of the real existing tolerances and the variable dynamic behavior. Calibrating the glow plugs is also not conceivable, as mass-produced components are involved here.
SUMMARY OF THE INVENTION
A primary object of the present invention is to provide a process and a device of the type initially described, with which the heating of the glow plugs of a diesel engine, including the thermal behavior of the glow plugs, can be controlled without using a measuring signal for feeding back the temperature of the glow plugs.
This is solved according to the present invention in the manners described below.
With the process and device according to the present invention, it is possible to consider the thermal situation of the glow plugs, since a physical model of the glow plugs is implemented in the control device. This model, which can be designed, for instance, in the form of a temperature resistance element with positive or negative resistance temperature coefficients, which is heated parallel to the glow plugs with low voltage and minimal current, permits feedback of the current temperature via its resistance. The thermal heating and steady-state behavior of the glow plugs can be emulated in their full dynamic by means of further electronic switching elements.
By the physical model integrated into the glow plug control system, independence of voltage dips on the vehicle is achieved, so that the thermal state of the glow plugs can be determined simply and precisely by the glow plug control, also after full resetting of the electronic control. The temperature range of the glow plug (up to 1100° C. for steel glow plugs, up to 1500° C. for ceramic glow plugs) is preferably projected onto the temperature range of the electronics (up to 125° C.).
This means in detail that a thermal model of the glow plugs is implemented in the glow control system in that electronic control and evaluation is incorporated in connection with a resistance temperature element or a heating element or a combination of both elements. Feedback of the glow plug temperature from the physical model then enables control based thereon or regulating of the glow plugs. The core of the physical model, at the same time, comprises a physical energy storage, whereof the energy content is proportional to the glow plug temperature or is inversely proportional. This physical energy storage can be, for example, a heating element with corresponding thermal mass or a condenser for storing electric energy.
According to the present invention physical modeling of the thermal behavior of the glow plugs results, whereby the corresponding physical model is integrated into the glow control system. This can also include mapping the engine operating state to the physical model.
Operating the glow plugs from every imaginable operating state is thereby optimized to achieve the shortest possible response times to reach the set temperature.
By using a correction module the glow plug temperature is regulated indirectly by a closed control circuit, which leads from the electronic control for controlling the glow plugs, from the correction module, and from the physical model back to the electronic controlling.
The physical model can also be coupled to measuring signals, which, e.g., reflect the ambient temperature or at least the stationary mode of the glow plug. For this purpose, a temperature sensor can be provided in the glow control device or the signal of a temperature sensor of the engine can be evaluated via an interface. For determining the temperature in stationary mode of the glow plug resistance measuring is carried out, and optionally averaging via several or all inbuilt glow plugs.
The device and process according to the present invention furnish improved repeat start protection for fast-start glow plugs and low-voltage glow plugs and offer the possibility of use as a pre-emptive regulator. This means that improved and more precise detection of the actual glow plug temperature, and guiding the glow plug temperature are possible via the more precisely and more easily detectable temperature of the physical model. The imaging and thus storing of the temperature state of the glow plugs is possible independently of the voltage supply of the electronics, so that, after full resetting, the current state of the glow plugs can be detected simply and precisely and optimal control can be selected. The physical model, which is implemented in the electronic control, can be further balanced within the context of manufacturing the electronics. According to the present invention, the memory provided is not static, but dynamic. In this way, the simulation of the cooling behavior is also possible without operating voltage, so that optimal control of the heating procedure of the glow plugs to achieve the shortest possible readiness, i.e., start capability of the engine can be achieved.
A particularly preferred embodiment of the invention will be described in greater detail hereinafter with reference to the attached diagrams, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of the glow rod of a glow plug,
FIG. 2 is a sectional view of a portion of the glow plug with the glow rod illustrated in FIG. 1 , and
FIG. 3 is a schematic diagram of an embodiment of the device according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
In FIGS. 1 & 2 , a standard glow plug made of metal is illustrated, which has variable resistance, which generally rises with increasing temperature. Within the metal glow plug 6 , for example, as illustrated in FIG. 2 , there is an internal helical combination 7 of a heating element without significant temperature coefficients, namely the heating helix 8 , and a heating element with positive temperature coefficients, namely the control or measuring helix 9 . Since there is no sufficiently quick thermal coupling, the dynamics at the combustion chamber side core tip can be determined from the change in the resistance, and the abovementioned dynamic follows only relatively passively. In addition, the resistances of all the glow plugs vary widely from mass manufacturing and the resistance course correlates only inadequately with the temperature course. Comparing or sorting all glow plugs is inconceivable due to additional costs. Additional temperature sensors 10 certainly can be provided, though they are associated with high costs and also have a limited life span. Recognizing the heating behavior of the glow plugs thus has tight restrictions placed on it, already partly covered by the tolerance of real glow plugs, so that no additional statement on the present temperature of the glow plugs can be made with statistically distributed resistances.
Direct feedback on the current temperature at the heating rod tip of the glow plugs is thus not possible for serial use.
As illustrated in FIG. 3 , a glow requirement is sent to the glow control system 2 , which is interpreted there so that the glow plugs 3 are fed with current according to requirements in a glow plug control system via a suitable interface of an overriding control instrument, for example, the engine control instrument 1 of an engine 14 .
As is further shown in FIG. 3 , in the illustrated embodiment of the invention, parallel to the glow plugs, a physical model 4 of the glow plugs is provided in the glow control system, the purpose of which is to image the thermal state of the glow plugs 3 . This physical model 4 is designed such that it images the temperature at the heating rod tip of a standard glow plug at least when the engine is idle. This applies both for heating and cooling of the glow plug.
The physical model 4 , in principle, comprises a physical energy storage, whose energy content is proportional or inversely proportional to the glow plug temperature. This physical energy storage can be, for example, a condenser, whose charged state is proportional to the temperature. The resistance of a correspondingly sized resistance temperature element with positive or negative resistance temperature coefficients inside the physical model can also serve as a measure for the thermal state of the glow plug.
The physical model 4 can also be designed fully in the form of computer-stored software, e.g., as a stored identification field.
As further shown in FIG. 3 , the state of the physical model 4 is evaluated and an input value 5 is formed therefrom, which is applied to the glow plug control 12 , which controls the glow plugs 3 via a driver 15 , e.g., in the form of power switches.
The above described device works as follows.
As soon as a glow requirement is sent to the glow control system 2 via the interface of an overriding control device, for example, the engine control device 1 , the glow plugs 3 are triggered, and parallel thereto the physical model 4 in the glow plug control. The state of the model 4 is determined and analyzed and applied as input value 5 at the glow plug control 12 as feedback of the glow plug temperature, so that the glow plug control system 2 can consider the thermal state of the glow plugs when the glow plugs are operated.
The physical model 4 implemented in the glow control system 2 can detect the dynamics very precisely, so that exact information on the temperature actually present on the glow plugs 3 is given, which opens up far-reaching possibilities for detecting and guiding the temperature of the glow plugs 3 .
To further heighten the accuracy, the temperature of the physical model 4 can be compared to another temperature, which is recorded at a site which well reflects the ambient temperature. This can be a measuring site 11 on a metal pressed screen, which is not receiving major current, for example, the communications interface.
It is an added advantage that, due to the fact that the physical model 4 is implemented in the glow control system 2 , the model or the integrated electronic components can be compared during production of the glow control system 2 , by means of which a further increase in accuracy is achieved. Evaluation of the resistance of the glow plugs 3 by measuring the current is inadequate to measure the temperature, in particular in dynamic phases, though in sufficiently stationary phases the resistance of the glow plugs can be compared to the values of the physical model 4 , which can serve as further increase in accuracy or for checking plausibility. Corresponding functionality of the control 2 for focused comparison between the glow plug resistance and the output signal of the physical model 4 can be implemented by corresponding software and memory in the electronic drive 12 .
The state of the physical model 4 is thus evaluated by appropriate electronics and is made available as a signal for processing for the electronic control 12 .
Since the physical model 4 , as explained, is operated parallel to the glow plugs 3 , i.e., experiences an equivalent or proportional energy input, it simulates the heating behavior of the glow plugs 3 . This simulation should be configured such that the heating and cooling behavior is simulated at least when the engine is idle. However, the physical model 4 in the glow control system 2 does not experience the energy supply or discharge as a glow plug in the combustion chamber via the combustion energy or the additional cooling, for example, in thrust mode. So that the physical model 4 fulfils its purpose and simulates the temperature of the glow plugs 3 as best as possible, apart from the parallel triggering of the physical model 4 , at the same time, the additional positive or negative energy input can be added mathematically by external influences, which deviate from the standard case. For this, a correcting module 13 is preferably provided which is located between the physical model 4 and the electronic drive 12 and takes into consideration the current engine state, for example, the speed, the torque, the injected quantity of fuel, the temperature etc., and accordingly modifies the control of the physical model 4 , such that the reference glow plug temperature output by the model matches the actual glow plug temperature.
For this purpose, in the simplest case, control of the physical model 4 can be limited by a fixed value. It is known that during engine operation glow plugs, at least in diesel engines with direct fuel injection, apart from in peripheral regions of low speed and very high load, have a higher energy requirement compared to the situation, when the engine is idle, to keep the set temperature of the glow plugs. It is normal to design the electronic control 12 such that the energy supply to the glow plugs is regulated such that the glow plug temperature is kept independently of the engine operating conditions. When the engine is running, and thus, as a rule, when the energy flow is higher to the glow plugs than when the engine is idle, it can be assumed that the glow plugs have the set temperature exactly. For these easily detected cases, the correcting module 13 can force the physical model 4 to a state corresponding to the set temperature.
When an even more precise image of the actual glow plug temperature is requested by the physical model 4 or in engines with indirect injection or other engines, in which the abovementioned simple limiting of the model by a fixed value is not sufficient, the additional positive or negative energy input is first detected by a measuring technique and in correlation with parameters available to the engine control device 1 or the glow control system 2 , such as e.g., the injected quantity of fuel, the speed, the inner torque, the air, engine, water or oil temperature. Based on the resulting data, an algorithm or a mathematical model is drawn up and integrated into the correcting module 13 , so that the latter modifies the control signal parallel to the glow plug current supply, such that the physical model 4 follows the actual temperature on the glow plug. In this way, the temperature of the glow plugs can be regulated advantageously in addition, in that a closed control circuit results from recording the temperature of the physical model 4 . Accordingly, overloading, error control etc, are avoided. A set temperature sent, for example, from the engine control device 1 to the glow control system 2 can then be converted relatively easily and monitored, whereby reaching this temperature can be fed back again to the engine control device 1 . This opens up further possibilities to bring the glow plugs 3 even faster than previously to the set temperature, because at the time only minimal heating rates are possible due to the deficient feedback of the resulting temperature on the glow plug 3 . | A process and device for controlling the heating of the glow plugs of a diesel engine. To be able to take into consideration the thermal behavior of the glow plugs while controlling the current supply of the glow plugs ( 3 ) of a diesel engine, the thermal behavior of the glow plugs ( 3 ) is emulated via a physical model. Formed on the corresponding output signal of the model ( 4 ), which is proportional to the glow plug temperature, is a reference signal, which as a control value, lies on the electronic control ( 12 ) controlling the heating flow of the glow plugs ( 3 ), which accordingly controls the heating of the glow plugs ( 3 ) using the actual glow plug temperature determined from emulation. | 5 |
TECHNICAL FIELD
The present disclosure relates generally to a cooling device and, more particularly, to an exhaust gas cooling device within the exhaust stream of an engine.
BACKGROUND
Internal and external combustion engines produce exhaust gases that may reach very high temperatures. These temperatures may be high enough to pose a safety hazard to any personnel present near the engine's exhaust outlet-to-atmosphere.
To correct this problem, some engine manufacturers use exhaust pipes of sufficient length to cool the exhaust gas before it enters the environment. Unfortunately, some exhaust temperatures are too high and require additional cooling solutions.
Today, many engines are equipped with catalytic converters and particulate filters in the exhaust system that may further increase the exhaust outlet-to-atmosphere temperatures. For example, particulate filters may be configured to collect unburned hydrocarbons—or soot—from the engine's exhaust. Periodically, the filter regenerates, which causes these collected hydrocarbons to undergo an exothermic reaction and burn. This exothermic reaction may result in a large release of thermal energy, thereby further increasing the exhaust-to-outlet temperature.
U.S. Pat. No. 3,875,745 to Franklin (“'745”) discloses a device utilizing the Coanda effect to introduce exhaust gas around a lip on one end of a venturi tube, causing the exhaust gas to flow in a high velocity film adherent to the inner surface of the tube. The laminar flow of '745 draws in a large volume flow of air through the center of the venturi, cooling 1000° F. exhaust gas down to almost ambient temperature in a distance of a few inches.
The device of '745, however, may not be suitable for many applications. For example, according to '745, “For effective operation, the gases must pass through catalytic converter at a temperature not lower than 1000° F.” Further, the device of '745 may result in a prohibitively high exhaust back-pressure, thereby detrimentally affecting the engine's Brake Specific Fuel Consumption. Even further, the device of '745 may be expensive to manufacture, making its cost prohibitively expensive.
The disclosed exhaust-gas cooling device is directed to overcoming one or more of the problems set forth above.
SUMMARY
In one embodiment of the present disclosure, a device for cooling a gas is provided. The device comprises an inlet having a first diameter, a mixing section downstream of the inlet and having a second diameter, and an opening in fluid communication with the mixing section and a source of air. In this embodiment, the second diameter is smaller than the first diameter and a vacuum is created for drawing in the air from the opening as gas passes from the inlet to the mixing section so that the air drawn into the mixing section mixes with the gas.
In another embodiment of the present disclosure, a method of cooling an exhaust gas of an engine is provided. The method comprises providing a venturi for receiving exhaust gas, drawing in aspirated air at a throat of the venturi, and cooling the exhaust gas by mixing the exhaust gas with the aspirated air.
In even another embodiment of the present disclosure, a method for mixing two gases is provided. The method comprises providing a first gas, providing a second gas, passing the first gas through a converging nozzle, creating a vacuum as the first gas passes through the converging nozzle, drawing in the second gas with the vacuum, and mixing the first gas with the second gas.
In yet another embodiment of the present disclosure, an exhaust system of an engine is provided. The exhaust system comprises an exhaust pipe comprising high pressure exhaust gas, a venturi tube positioned within the exhaust pipe for receiving the exhaust gas, and an opening within a throat of the venturi tube. In this particular embodiment, aspirated air is drawn in the throat of the venturi tube and mixes with the exhaust gas.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic illustration of an engine having an exhaust cooling device according to an exemplary embodiment of the present disclosure; and
FIG. 2 is a cross-sectional view of a particular exhaust cooling device;
FIG. 3 is a cross-sectional view of another particular exhaust cooling device;
FIG. 4 is a cross-sectional view of yet another particular exhaust cooling device;
FIG. 5 is a cross-sectional view of even yet another particular exhaust cooling device; and
FIG. 6 is a cross-sectional view of another particular exhaust cooling device.
DETAILED DESCRIPTION
FIG. 1 illustrates an engine 10 with a cooling device 100 according to an exemplary embodiment of the present disclosure.
In this particular embodiment, engine 10 has intake manifold 11 and exhaust manifold 12 . Intake air enters intake manifold 11 to facilitate the combustion within engine 10 . Exhaust gas 120 —shown in FIGS. 2 - 6 —from the combustion process then enters exhaust manifold 12 .
The oftentimes high-temperature and high-pressure exhaust 120 may then be used to drive a high-pressure turbocharger 20 . In this case, exhaust gas 120 drives turbine 21 to impart rotational energy to compressor wheel 22 . Compressor wheel 22 is connected to turbine 21 via a common shaft. As the high-pressure exhaust 120 drives turbine 21 , the rotational energy imparted on compressor 22 helps pressurize intake air prior to entering intake manifold 11 .
In some embodiments, it may be desirable to add a second turbocharger 30 . Low-pressure turbocharger 30 , like turbocharger 20 , may have a turbine 31 and compressor 32 for further pressurizing intake air.
In the particular embodiment of FIG. 1 , once exhaust gas 120 exits turbine 31 , exhaust gas 120 enters particulate filter 51 . In this embodiment, a regeneration device 50 is positioned upstream of filter 51 . Regeneration device may be, for example, a burner configured to generate heat for regenerating filter 51 .
As exhaust gas 120 enters filter 51 , soot, ash, and/or any other particulate material may be deposited within filter 51 . Periodically, it may be desirable to regenerate filter 51 in order to burn any collected hydrocarbons—soot. In this particular embodiment, the regeneration may be initiated by regeneration device 50 . Device 50 may be configured to generate heat to begin the regeneration of filter 51 . During the regeneration of filter 51 , an exothermic reaction occurs as the soot burns, resulting in very high temperatures. These temperatures may even exit filter 51 at or above 650° C.
After exhaust gas 120 exits filter 51 , some exhaust gas 120 may enter gas induction line 60 . In this particular embodiment, cooler 61 may then cool the exhaust gas 120 that enters line 60 . Cooler 61 may be any type of heat exchanger that is known in the art, such as a parallel-flow heat exchanger that uses engine 10 jacket water (not shown) as a cooling sink.
In this particular embodiment, once exhaust gas 120 exits cooler 61 , control valve 62 may be actuated for regulating the amount of exhaust gas 120 that mixes with ambient air 70 . Control valve 62 permits for a controlled mixing of recirculated exhaust gas 120 with ambient air 70 prior to entering compressors 32 and 22 of turbochargers 30 and 20 , respectively.
After the pressurized mixture of ambient air 70 and recirculated exhaust gas 120 leaves compressor 22 , it may then be cooled in cooler 75 . Cooler 75 may be any known heat exchanger known in the art. In one particular embodiment, cooler 75 is an air-cooled air cooler.
In some embodiments, as the one depicted in FIG. 1 , crankcase air from engine 10 block may be vented. In this particular embodiment, crankcase ventilation exits engine 10 block via line 40 , where it is sent to the engine's 10 exhaust line. In other embodiments, which are not shown, the crankcase ventilation may be vented to atmosphere and it may further be filtered to remove any particulates.
For the particular embodiment of FIG. 1 , exhaust gas 120 that is not recirculated via loop 60 enters exhaust line 90 . As stated, exhaust gas 120 entering line 90 may be high. For example, during regeneration of filter 51 , the exhaust temperature may be in excess of 650° C. To help minimize the risk of hazard to personnel and equipment, cooling device 100 cools exhaust 120 before exhaust 120 enters environment 80 .
Referring to FIGS. 2-6 , various embodiments of exhaust gas 120 cooling device 100 are depicted. In particular, FIGS. 2-6 depict cross-sectional views of various cooling devices 100 . In these various embodiments, exhaust gas 120 enters device 100 from the left, the inlet, and exits to the right. Air 101 enters device 100 and mixes with exhaust gas 120 . In most cases, air 101 entering device 100 is much cooler than exhaust gas 120 and the mixture 125 of air 101 and exhaust gas 120 results in a cool blend. In many cases, the mixture 125 exiting device 100 is sufficiently cooled for safe release to environment 80 .
Referring to the particular embodiment of FIG. 2 , as gas 120 enters device 100 , the converging shape of device 100 from the inlet to the middle section—or throat—results in an increase in velocity of gas 120 from left to right. As the velocity of gas 120 increases, an associated pressure drop results. This associated pressure drop is well understood by one skilled in the art as Bernoulli's principle. The resultant pressure drop creates a slight vacuum in device 100 . As the pressure within device 100 is slightly lower than atmospheric pressure, aspirated air 101 is drawn into device 100 from opening 124 . The drawn in aspirated air 101 mixes and dilutes with exhaust gas 120 downstream of opening 124 , resulting in a mixture 125 with a cooler overall temperature.
Now referring to FIG. 3 , another embodiment of cooling device 100 is provided. The operation of device 100 in FIG. 3 is similar to the operation of device 100 in FIG. 2 , in that the converging shape of device 100 and opening 124 allow for the mixing of exhaust gas 120 with aspirated air 101 .
In the embodiment of FIG. 3 , however, perforations 121 are present to promote mixture of aspirated air 101 with exhaust gas 120 . In this particular embodiment, some of the exhaust gas 120 and aspirated air 101 mixture 125 may exit cooling device via perforations 121 . In some cases, additional aspirated air 101 may enter perforations 121 to further mix and dilute exhaust gas 120 .
Now referring to FIG. 4 , another embodiment of cooling device 100 is provided. The operation of device 100 in FIG. 4 is similar to the operation of device 100 in FIG. 3 , in that the converging shape of device 100 , opening 124 , and perforations 121 allow for the mixing of exhaust gas 120 with aspirated air 101 .
In the embodiment of FIG. 4 , however, cooling fins 122 are present for promoting the transfer of heat from cooling device 100 to the outside atmosphere. Cooling fins 122 are connected to device 100 and project outward from device 100 , as shown. The cooling fins 122 conduct heat from device 100 and, through convection, transfer heat to the surrounding environment.
Now referring to FIG. 5 , another embodiment of cooling device 100 is provided. The operation of opening 124 and perforations 121 is similar to the operation of FIGS. 3 and 4 for mixing exhaust gas 120 with aspirated air 101 .
In the embodiment of FIG. 5 , however, cooling fins 123 are present for promoting the transfer of heat from exhaust gas 120 to cooling device 100 . Cooling fins 123 are connected to device 100 and project inward from device 100 , as shown. Through convection, exhaust gas 120 transfers heat to cooling fins 123 , which in turn transfer heat to device 100 through conduction.
Now referring to FIG. 6 , another embodiment of cooling device 100 is provided. In this particular embodiment—as with the others of FIGS. 2 - 5 —exhaust gas 120 enters device 100 from the left. Unlike the venturi-shape of devices 100 in embodiments of FIGS. 2-5 , however, the middle-throat section of device 100 in FIG. 6 does not diverge from the throat to the outlet. As the passage of device 100 converges, the velocity of gas 120 increases, thus creating a pressure drop. A slight vacuum is created and draws aspirated air 101 into device 100 , where it mixes with exhaust gas 120 . The resultant mixture 125 of exhaust gas 120 and air 101 then exits device 100 to the right.
INDUSTRIAL APPLICABILITY
Referring back to FIG. 1 , in operation, cooling device 100 cools at least some of the exhaust gas 120 exiting engine 10 before it is released to environment 80 .
During operation of engine 10 , exhaust gas 120 may or may not pass through one or two turbochargers 20 and 30 . Afterwards, exhaust gas 120 may or may not then pass through particulate filter 51 .
Particulate filter 51 may be configured to collect particulate matter from exhaust gas 120 , such as soot or hydrocarbons. Once filter 51 collects any soot or hydrocarbons, filter 51 may regenerate to burn at least some of the filtered soot or hydrocarbons.
In the embodiment of FIG. 1 , regeneration may be initiated with the addition of thermal energy from regeneration device 50 . In at least one example, device 50 may be a burner configured to direct heat to filter 51 , thus causing soot or hydrocarbons to burn within filter 51 . As depicted, burner 50 may be positioned upstream of filter 51 . This burn results in the release of thermal energy, which may further increase the temperature of exhaust gas 120 . In some cases, the temperature of exhaust gas during regeneration may be as high as 650° C. or higher.
Some, all, or none of exhaust gas 120 may then enter recirculation line 60 , where it would be mixed with ambient air from intake 70 . Some of this exhaust gas may also be cooled prior to mixing with cooler 61 . In at least one example, cooler 61 may be a jacket-water cooled parallel-flow heat exchanger. The reader should appreciate, however, that any heat exchanger known in the art may be used to cool exhaust gas 120 within line 60 . The reader should also appreciate that a cooler 61 is also not necessary.
For the exhaust gas 120 that is not mixed with intake air 70 , the gas 120 enters cooling device 100 , where some or all of the gas 120 may be cooled to a level safe for discharge to environment 80 .
Referring to FIGS. 2-6 , as exhaust gas 120 enters device 100 from the left, a vacuum is created as the velocity of the gas 120 increases with the converging passageway. This increase in velocity results in a corresponding pressure drop, which creates a vacuum within device 100 . The vacuum then draws in aspirated air 100 through opening 124 .
As aspirated air 101 mixes with exhaust gas 120 , the temperature of exhaust gas 120 most often drops, as the temperature of air 101 is usually lower than the temperature of exhaust gas 120 . The resultant mixture 125 then leaves device 100 from the right, as shown, towards environment 80 .
Other embodiments of the disclosed exhaust treatment system 10 will be apparent to those skilled in the art from consideration of the specification. It is intended that the specification and examples be considered as exemplary only, with the true scope of the invention being indicated by the following claims. | A device for cooling a gas is provided. The device comprises an inlet having a first diameter, a mixing section downstream of the inlet and having a second diameter, and an opening in fluid communication with the mixing section and a source of air. The device is such that the second diameter is smaller than the first diameter and a vacuum is created for drawing in the air from the opening as gas passes from the inlet to the mixing section so that the air drawn into the mixing section mixes with the gas. A method for mixing two gases and an exhaust system are also provided. | 5 |
FIELD OF THE INVENTION
[0001] This invention is related to automotive drive train adaptors, specifically an adaptor which permits the mating of drive train components not normally designed to be connected.
BACKGROUND OF THE INVENTION
[0002] The present invention is directed to an adaptor which permits a Chevrolet Corvette C5 or C6 rear end assembly to be used in a rebuild of an older Corvette, such as a C1, C2, or C3 generation model.
[0003] The Corvette has had six generations of vehicle design, typically known in the industry as C1 through C6, with the C1 being produced from 1953 to 1962, the C2 being produced from 1963 to 1967, the C3 being produced from 1968 to 1982, the C4 being produced from 1984 to 1996, the C5 being produced from 1997 to 2004, and the C6 being produced from 2005 to date.
[0004] Each generation has maintained a fundamental design in its body, suspension, drive train, and engines, with changes being introduced from model year to model year within a generation to meet pollution requirements and changes in gasoline chemistry, to introduce appearance features, or to change engine and transmission specifications for sales promotion purposes.
[0005] Through the years, the Corvette has become an American icon in the automotive industry. Attractive styling, sports car performance, and the use of fiberglass and plastic materials and exotic metals have attributed to a long standing desirability for older Corvette models among the public.
[0006] An industry now exits in which older Corvettes are rebuilt or remanufactured from the ground up, i.e., from the frame outward. These rebuilt Corvettes often sell privately or at auction for in excess of $150,000 depending upon the model. The rebuilding of an older Corvette becomes the building of a Corvette as new parts from frame to suspension, to brakes, to engine, to drive train are introduced. Of necessity, the body remains, in whole or in part, from the original factory production.
[0007] Through the various generations, changes have occurred in engines, drive trains, transmissions and suspensions. The C1 Corvette began with an inline six-cylinder engine, a two-speed automatic transmission, drum brakes and a solid rear axle with longitudinal leaf springs. A “small-block” (1955-1956) V8 engine and constant flow fuel injection was later introduced for the C1 Corvette for 1957-1961 in a 283 cu. in. engine.
[0008] The C2 Corvette started with independent rear suspension, and a larger small-block (327 cu in) V8 engine with optional electronic ignition. As the C2 model years progressed with even higher horsepower with the larger (327 cu. in.) V8 engines and introduced two big-block (396 cu in and 427 cu in) V8 engines with modified automatic and manual transmissions and changes in carburation. These C2 big-block Corvettes are one of the most desirable antique vehicles in the United States.
[0009] The C4 Corvette introduced a light-weight composite, transversely mounted, monoleaf front suspension that has been the standard for Corvettes ever since. A larger big-block (454 cu in) V8 engine with redesigned transmission was also introduced. The rear suspension remained with independent pivoting axels, leaf spring suspension similar to the design of the C2 Corvette. However, in later model years a cross-fire, throttle body injection engine was introduced, as well as plastic composite rear coil springs, thinner body panels, a catalytic converter, and an aluminum differential. More of the changes in model years addressed engine changes, engine modifications and transmission changes than changes in other portions of the vehicle.
[0010] As with earlier generations, the C4 Corvette introduced a change in body style and looks. It also introduced changes in engines, carburetion/fuel injection and transmissions, as well as a transverse composite leaf spring in the rear.
[0011] The C5 Corvette introduced major changes over the previous generations. Instead of a beam/rail type perimeter frame onto which the body was bolted, the C5 had a hydroformed perimeter frame integral with the body. The front and rear suspension assemblies which hold the engine, transmission, differential and suspension structure were joined by a center torque tube. The front suspension included alloy upper and lower control arms and steering knuckle, transverse monoleaf plastic composite spring, steel stabilizer bar, spindle offset and gas-pressurized shock absorbers positioned to operate within the cavities of the front wheels. The rear suspension was an independent 5-link design with toe-in and camber adjustment, alloy upper and lower control arms and knuckle, transverse monoleaf plastic composite spring, steel stabilizer bar and tie rods, tubular u-joint metal matrix composite drive shafts, and gas-pressurized shocks positioned to operate within the cavities of the rear wheels. The new geometry of the C5 rear suspension, including the new transverse leaf spring, offered greatly improved handling and lateral stability as well as providing an improved ride which reduced body rattles and squeaks.
[0012] The rear suspension short-long arm and transverse leaf spring independent suspension configuration of the C5 was carried over into the C6 Corvette. However, the geometry of the cradles, control arms, knuckles, dampers and stabilizer bars was redesigned. These changes, including adjustments in various dimensions, have produced ever-improved ride and handing, less road noise, and better body control under greater lateral acceleration.
[0013] Both the C5 and the C6 Corvette rear suspensions have height adjustments for raising or lowering the vehicle. It is well accepted in the marketplace that the C5 and C6 rear suspension designs are great improvements over the previous generations of Corvettes. Like the C4, the C5 and C6 suspensions continued with the leaf spring configuration, where the link arms permit the shock structure to extend into the interior space of the wheels.
[0014] Like the C5 Corvette, the present C6 Corvette has its transmission mounted to the rear differential. This feature was introduced in an effort to obtain a 50-50 weight distribution in the vehicles. However, for body clearance when adapting a C5 or C6 rear suspension to an older C1 through C3 Corvette, the transmission must be mounted to the engine.
[0015] While more and more Corvette enthusiasts are requesting C5 or C6 rear suspensions in their rebuilt older generation vehicles because of the better handling and ride, such crossover use in not possible without modification to the drive train and body.
[0016] Older Corvettes can have one-piece drive shafts connecting the transmission to the rear differential, with the transmission being mounted at the engine. In order to use a C5 or C6 rear suspension on the older Corvettes it is necessary to eliminate the rear mounted transmission and provide an adaptor between the drive shaft and the differential.
[0017] An object of the present invention is to provide an adaptor which mounts to an existing C5/C6 differential with the same sealing function as the C5/C6 transmission housing.
[0018] A second object is to provide an adaptor which will handle the power from a modern “crate” engine, an original specification engine and transmission when coupled to the end of the drive shaft.
[0019] A third is to provide an adaptor with a structure for more than one mounting configuration to accommodate different suspension height adjustments.
[0020] Another object is to provide an adaptor with a structure for coupling to the end of the drive shaft from a front-mounted transmission.
[0021] A further object is to provide an adaptor with sufficient lubrication to promote longevity of operation and reduce heat build-up.
SUMMARY OF THE INVENTION
[0022] The objects of the present invention are realized in an adaptor which mounts to the rear differential of a C5 and C6 generation Corvette suspension assembly in place of the factory transmission housing normally attached to the differential, which has been removed. The adaptor includes a housing machined from a solid alloy block, with a front (outside) and rear (inside) faces. The inside face of the adaptor housing includes a toroidal-shaped flange which carries a peripherally mounted sealing ring, with the flange and sealing ring operating to seal the opening in the differential created upon the removal of the O.E.M. transmission housing. The outside (front) face of the adaptor housing has an outwardly projecting boss. A cylindrical cavity (bore) extends longitudinally through the housing.
[0023] The housing supports a stub shaft which couples the end of the drive shaft from a front mounted engine/transmission to the rear differential. The shaft support within the housing includes a pair of bearings, a larger rear (inside) bearing and a smaller front (outside) bearing being positioned from about ½ inches to about 2 inches apart depending upon the housing geometry. In the preferred embodiment, the bearing races of the inside and outside bearings are spaced about ½ inches apart.
[0024] The housing has a cylindrical cavity (bore) which forms a central tubular-like portion shaped as the result of the boring through the alloy block. This tubular-like portion holds the bearings that in turn support the shaft which passes through it. Surrounding, and laterally extending outwardly from the central tubular-like portion of the housing are projecting ears having through holes for mounting studs and also a build-out wall carrying threaded holes for receiving bolts. These structures are used to mount the housing to the differential with the same mounting components used for mounting the removed O.E.M. transmission.
[0025] A front boss, which extends forward from the front (outside) face of the housing block, receives the outside (front) bearing race and its bearing and permits the overall weight of the housing structure to be reduced by permitting a reduction in the thickness of the projecting ears and the thickness of the wall build-out mounting structures. In addition, the boss has a thinner wall than the body of the housing, which permits more heat to dissipate from the front (outside) bearing region, thereby permitting the use of a smaller front bearing, than with the rear bearing which is positioned within the main body of the housing.
[0026] The rear bearing race and its rear bearing are inserted into the rear portion of the bore which is concentric with the center of the toroidal-shaped flange.
[0027] The bore has two internal annular shoulders with different through bore diameters which are stepped from one to the other, with the inner (rear) shoulder having the smaller (bore diameter) opening and the outer (front) shoulder having the larger (bore diameter) opening. The inner shoulder operates as the abutment stop for both the front and rear bearing races. The longitudinal thickness of this shoulder establishes the spacing between the outside and inside bearings.
[0028] The portion of the bore leading from the rear (inside) face of the housing to the inner (rear) shoulder is a neat (tight) fit for the circumference of the rear (inside) bearing race. Similarly, the inside bore diameter of the outer (front) shoulder is a tight fit for the circumference of the outside (front) bearing race. The bore portion leading from the front (outside) face of the housing to the outer (front) shoulder is about the same size in bore diameter as that leading from the rear (inside) face to the rear (inside) shoulder. This outside (front) bore portion has an annular oil grove in its inside wall positioned away from the front (outside) shoulder.
[0029] A pair of grease ports lead from two separate side faces of the housing to the inside face of the rear (inside) annular shoulder. Each grease port is tapped and threaded to receive a fitting. The first port is positioned on a side face of the housing significantly lower than the second port, which is positioned on the top side face of the housing. The lower first port is fitted with a snap-fit grease fitting for feeding grease to the interior of the housing at the inside (rear) annular shoulder. The upper second port is fitted with a pressure relief/bleeder fitting.
[0030] As the bearings are open bearings, grease forced into the housing will first fill the bearings and then fill the bore about the shaft in both the front (outside) and rear (inside) bore portions. These grease pockets provide additional sources of lubrication for the bearings. A rear (inside) grease/oil seal having an internally mounted double layer wiper seal is mounted at the back (inside) bore portion housing wall.
[0031] A front (outside) grease/oil seal is mounted at the front (outside) bore portion housing wall. A coupling yoke mounted to the front of the shaft carries a dust cover for the front (outside) grease/oil seal.
[0032] The shaft has a spline section at both of its ends. The rear (inside) spline mates with a gear in the differential. The front (outside) spline is used to mount the coupling yoke.
[0033] Inboard from the front (outside end) shaft spline is a section of the shaft which is machined to receive the rear (inside) bearing and then the front (outside) bearing, both in press-fit fashion. This machined section terminates at a peripherally/outwardly extending circular flange machined with a flat face adjacent the machined shaft surface and with a fillet on the opposite side.
[0034] The shaft has a threaded end outboard of its yoke-mounting spline section. This treaded end receives a nut which tightens against the hub of the yoke to draw the assembly together.
[0035] The yoke has a Y-shaped coupling end of cast material. A central longitudinal bore has been cut though the hub of the coupling with an internal spline. The side opposite the Y-shaped coupling has a projecting boss or cylindrical projection for abutting the back of the front (outside) bearing. The opposite end of the hub has a machined face against which a tightening nut operates when engaging the threads at the shaft end.
[0036] The outer (front face) of the housing has a series of threaded holes above and below the housing boss. These holes are for mounting a bracket, which can be mounted above or below the housing boss, depending upon the geometry of the assembly. The bracket has a pair of tabs or ears for mounting it to a pair of frame mounts.
[0037] The adaptor is assembled by first pressing the front (outside) and rear (inside) bearing races into the bore to abut the inner (rear) annular shoulder, which has the grease openings on its inside face. The rear (inside) bearing is pressed over the machined section of the shaft to abut the machined face of the flange.
[0038] The shaft is extended through the housing, and the front bearing is started onto the machined section of the shaft. A crushable separator may be used to separate the bushings until the shaft assembly is tightened. The front seal is tapped into place at the front bore opening. Then the coupling's spline section is started onto the mating spline section on the shaft. The nut is then started on the threaded end of the shaft. Tightening the nut forces the two bearings into the housing bores. When the bearings are sufficiently “set”, i.e., the assembly is sufficiently tight. Then the rear (inside) grease seal is assembled over the outside edge of the flange and the rear (inside) dust cover is tapped tight against the rear (inside) bore opening. The housing is then greased to completely fill all spaces with grease. Then bearing play is checked and the nut is finally tightened to set the bearing tightness for operation.
[0039] The housing is mounted to the differential at the five mounting points of the removed O.E.M. transmission.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] The features, advantages and operation of the present invention will become readily apparent and further understood from a reading of the following detailed description with the accompanying drawings, in which like numerals refer to like elements, and in which:
[0041] FIG. 1 is a partial perspective view of the adaptor of the present invention mounted to the rear differential of a C5 generation rear suspension which is mounted to the frame of an earlier generation Corvette;
[0042] FIG. 2 is a second partial perspective view of the adaptor of FIG. 1 with the drive shaft connected to the coupling of the adaptor;
[0043] FIG. 3 is a perspective view of the adaptor mounted to the rear differential with the mounting bracket above the shaft for holding mounting bushings;
[0044] FIG. 4 is a front perspective view of the assembled adaptor for the set up of FIG. 3 before being mounted;
[0045] FIG. 5 is an opposite side perspective view of the assembled adaptor with a bracket;
[0046] FIG. 6 is a rear perspective view of the assembled adaptor with a lower mounted bracket;
[0047] FIG. 7 is an exploded assembly view of the adaptor from a front perspective view;
[0048] FIG. 8 is a side cross-sectional view of the adaptor taken as shown in FIG. 5 ;
[0049] FIGS. 9 a and 9 b are front and front-perspective views of the housing portion of the adaptor, respectively;
[0050] FIGS. 10 a and 10 b are rear and rear-perspective views of the housing, respectively;
[0051] FIG. 11 is a bottom view of the housing with the rear seal ring installed on the periphery of the rear flange;
[0052] FIG. 12 is a front-perspective view of the bracket;
[0053] FIG. 13 is a side view of the stub shaft; and
[0054] FIG. 14 is a front view of the drive shaft coupling yoke.
DETAILED DESCRIPTION OF THE INVENTION
[0055] The present invention is an adaptor 21 , FIG. 1 , for mating the front mounted engine and transmission of an older generation Corvette to a newer generation, specifically a C5 or C6 rear differential and suspension. The adaptor 21 , FIG. 1 , bolts to the front of a C5 or C6 differential 23 in place of the removed O.E.M. transmission. The adaptor 21 includes a housing 25 , FIGS. 1-2 . A bracket 27 is bolted to the front face 29 of the housing 25 . This bracket 27 also bolts to frame mounts 31 . This bracket 27 can be bolted below a shaft 33 (not shown in FIG. 1 ) and coupling yoke 35 as shown in FIG. 1 , or above them, depending upon the geometry of the vehicle frame 37 and the mounting configuration of the rear suspension assembly of which the differential 23 is a part.
[0056] The adaptor 21 assembly, FIGS. 2-8 , and in particular, the housing 25 carries a pair of threaded holes 39 (not shown in FIG. 2 ) near the top of its rear/inside face 41 and another near the bottom (not shown in FIG. 2 ) for mounting the housing 25 with the differential 23 , with mounting bolts 43 . Internal to the housing 25 is a stub shaft 33 (not shown in FIGS. 1-3 ). In addition, mounted on the front/outside end of the stub shaft 33 is the coupling yoke 35 to which the vehicle drive shaft 45 is connected, FIG. 2 . The housing 25 is machined from a block of alloy material.
[0057] The housing 25 , FIGS. 3-4 , has a series of four threaded holes 47 near the top of its outer face 29 extending in an arc above a front boss 49 , which boss projects forward from the outer/front face 29 of the housing 25 . A second series of similar sized and spaced threaded holes 47 are below the front boss 49 in a similar arc.
[0058] The threaded holes 47 are used to mount a bracket 27 to the front/outer face 29 of the housing 25 , either above or below the boss 49 with fastening bolts 51 . The bracket 27 connects to frame mounts 31 above the differential, FIG. 3 , or below the differential, FIG. 5 , depending upon the geometry of the frame-to-rear suspension setup. FIG. 4 shows the bracket 25 attached in the upper position, while in FIGS. 5-6 the bracket 25 is in the lower position.
[0059] The assembled adaptor 21 as shown in FIGS. 4-6 has a stub shaft 33 which passes completely through the housing 25 . The rear/inside end of the shaft 33 is splined with a rear spline 53 extending to the rear/inside end of the shaft 33 . The opposite end of the shaft 33 has the coupling yoke 35 mounted thereto and held on with an end nut 55 , FIG. 3 . The rear/inside face 41 of the housing 25 carries a toroidal-shaped flange 57 through which the stub shaft 33 extends. This flange 57 and other housing features are discussed further below.
[0060] FIG. 7 is an exploded assembly view of the adaptor 21 shown from a side view. FIG. 8 is a side cross-sectional view of the assembled adaptor 21 taken as shown in FIG. 5 .
[0061] The housing 25 has a central bore 59 machined through it from its rear/inside face 41 to its front/outside face 29 . The shaft 33 extends through the bore 59 and is supported by a front bearing 61 and a rear bearing 63 . Each of these bearings is a thrust bearing with cylindrical rollers. There are mating front 65 and rear 67 bearing races, respectively. A front grease seal 69 and a rear grease seal 71 , seal the respective ends of the shaft and bearings. A tubular spacer is positioned between the bearings 61 , 63 . This spacer is crushable when the assembly is tightened.
[0062] The housing through bore 59 includes a pair of interior annular flanges which will be discussed further below. The backs of the bearing races 65 , 67 abut one of these flanges to establish the position of the bearings 61 , 633 within the housing 25 .
[0063] The bearings and bearing races are supplied by The Timken Company. The product numbers for these bearings 61 , 63 and races 65 , 67 are product numbers M88010, M88048 HM89444, and HM89410, respectively. The grease seals are supplied by SKF USA. The product numbers for these seals 69 , 71 are CRW1 R and HMSA25P, respectively.
[0064] The housing 25 , itself, is shown in FIGS. 9 a , 9 b , 10 a , 10 b and 11 , and has an irregular shape. Its overall outline is hexagonal with a smaller ear 77 on one bottom side and a larger ear 79 on the other bottom side. It is machined from high-strength aluminum alloy with a center bore 59 of about 2 inches in diameter in its smallest section. The size of the housing is about 3⅜ inches from the front face of the front boss 49 to the rear face of the toroidal flange 57 . The overall height of the housing is about 6½ inches, and the overall width is about 9⅜ inches.
[0065] The toroidal flange 57 is about 6 inches in diameter with a 3-inch diameter bore opening 59 at its rear face. This flange 57 is about ⅜ inches thick, i.e., it extends about ⅜ inch outward from the rear face 41 of the housing 25 . A 1/16 inch deep groove 73 extends about the peripheral wall of the flange 57 and holds an O-ring seal 75 . When the housing is mounted onto the rear differential of the vehicle, the seal 75 seals the opening of the differential 23 to prevent grease from leaking out.
[0066] The threaded bolt holes 39 , previously not shown on FIG. 2 , are easily seen on the rear face 41 of the housing 25 , FIG. 10 a , and are each about ½ inch away from the edge of the toroidal flange 57 . These holes 39 each receive 5/16 inch fastening bolts 51 in the mounting positions for the vehicle's differential.
[0067] The 3-inch diameter bore 59 extends into the housing a distance of about 1½ inches to terminate in a first internal annular shoulder 81 having an inside (bore) diameter of about 2⅛ inches in diameter, FIG. 10 a.
[0068] Each of the smaller and larger ears 77 , 79 is shaped to provide a fastening point having a drilled hole 83 , 85 therethrough. These holes are each ⅜ inches in diameter and have about a ⅝ inch deep, ⅝ inch diameter counter 87 sink on the front/outside housing face 29 side of each ear 77 , 79 .
[0069] The two sets of four threaded holes 47 for holding the bracket 27 , are spaced in a circular arc of about 120 degrees, on a 3-inch bolt radius, with one set of holes 47 above and other set below the front boss 49 , FIGS. 9 a , 9 b . Each of these bracket mounting holes is tapped to receive a ⅚ inch bolt. The arc center of these holes is about 1 inch away from the outside wall of the front boss 49 .
[0070] Front boss 49 has about a 4-inch outer diameter and a 3-inch inner diameter which extends inward about ¾ inches to terminate in a second internal annular shoulder 89 , FIGS. 9 a , 9 b . This shoulder 89 is about 3/16 inch high, i.e., it extends inwardly to establish its internal bore at about 2⅝ inches in diameter.
[0071] The second shoulder 89 is about ¾ inches deep (wide) and terminates against the first internal annular shoulder 81 . The first internal shoulder 81 is about ½ inches wide and joins the second shoulder 89 to the 3-inch bore 91 extending from the outer face of the toroidal flange 57 .
[0072] A first grease passageway 93 extends from a side face 95 of the housing 25 to the inside face of the first internal annular shoulder 81 . This first grease passageway is fitted with a NPT Zerk-type grease fitting 97 .
[0073] A second grease passageway 99 extends from the top face of the housing 25 to the inside face of the first internal annular shoulder 81 . This second grease passageway is fitted with a plug 103 which can have a pressure-indicating, air-release, spring biased pin.
[0074] The bracket 27 , FIG. 12 , has a mounting wall 105 with an arc-shaped cutout section 107 to provide clearance for the front boss 49 . Four holes 107 are drilled through the mounting wall 105 about the arc-shaped cutout to line up with either of the upper or lower four threaded holes 47 on the housing front/outside face 29 . A pair of frame-mount receiving ears 111 extend perpendicularly outward from the mounting wall 105 at either end of the bracket 27 . Each ear 111 has a ½ inch drilled hole for receiving and holding a frame mount 31 . The bracket is about 12 inches long, with the ears each being about 2½ inches long by 2 inches wide. The bracket mounting wall 105 and the ears 111 are of ¼ inch thick, tempered, high carbon steel plate.
[0075] The shaft 33 . FIG. 13 is about 15 inches long, end-to-end. The rear portion 113 of the shaft has been machined to have about a 1 inch outside diameter, and is about 8¾ inches in length from the rear of the spline 53 to a fillet 115 side of a circular flange 117 . The rear spline portion 52 is about 2 inches long.
[0076] The circular flange 117 is about ¼ inch wide and 2 inches in diameter. The opposite side 119 of the circular flange 117 is machined flat to abut the rear bearing 63 . Forward of the machined flat side 119 of the flange is a machined and polished section 121 of the shaft 33 , which receives and holds both bearings 61 , 63 and bearing races 65 , 67 . This polished section 121 is about 2⅜ inches long and has about a 1¼ inch outside diameter. Forward of the polished section 121 the shaft is necked down to about 1 inch in outside diameter leading to a front spline 123 . This front spline section 123 is about 1⅜ inches long. Outboard/forward of the front spine 123 the shaft 33 is machined and threaded into a 1 inch long, 11/16 inch diameter threaded bolt portion 125 for receiving the end nut 55 .
[0077] The drive shaft coupling yolk 35 is shown in greater detail in FIGS. 7 and 14 . This coupling 35 includes a pair of U-bolts (not shown) for engaging the arms of the yolk. The coupling 35 is provided by Greg Moser Engineering, Inc. product number PY210-9. It is a 1310 series pinion yoke having U-joint with 28 internal splines 135 ; and it is made of forged steel. The coupling U-joint portion 127 is about 3 inches deep with arms 129 about 2⅛ inches apart. A stub cylinder 131 extends from the opposite end of the coupling 35 from the U-joint 127 . This cylinder 131 is machined to be about ⅞ inch long, with an outside diameter of about 1⅞ inches. A dust shield 133 for the front grease seal 69 is peened into place on the cylinder 131 at a location where the U-joint 127 and the cylinder 131 meet.
[0078] The internal 28 spline section 135 extends thorough the coupling 35 from the base of the U-joint portion 127 to about 11/16 inch from the outside end of the cylinder 131 .
[0079] The two arms 129 of the U-joint portion 127 of the coupling are bifurcated into two pads 137 both of which are drilled to receive an end of a U-bolt. Each U-bolt is forged to be about 1⅞ inches long, and to receive and hold a transverse bar of about 1 inch in outside diameter, with the ends of each U-bolt being threaded for 5/16 inch lock nuts (not shown).
[0080] Many changes can be made in the above-described invention without departing from the intent and scope thereof. It is therefore intended that the above description be read in the illustrative sense and not in the limiting sense. Substitutions and changes can be made while still being within the scope and intent of the invention and of the appended claims. | An adaptor for an older Corvette drive train provides a structure for coupling the drive shaft extending from a front-mounted transmission to the differential of a C5 or C6 Corvette rear suspension in which the rear mounted transmission has been removed. A housing holds a stub shaft for rotation on front (outside) and rear (inside) bearings. The shaft has a coupling yoke mounted to its front end and engages the differential gearing at its other (rear) end. The housing mounts to the differential at the five mounting points of the removed transmission. A bracket which attaches to frame mounts can be mounted to either the top or bottom front (outside) face of the housing, depending upon the suspension-to-frame geometry. A circular flange on the shaft positions and holds the inside bearing and a rearward extending boss on the yoke positions and holds the outside bearing. A crushable tubular spacer fits over a portion of the shaft and holds the front and rear bearings apart during assembly and while the shaft assembly is drawn up. Two grease ports and fittings access the interior of the peripheral sealing ring to meet and seal the differential opening. | 1 |
BACKGROUND
[0001] The present invention relates to an engine driven agricultural tractor cooling system with a main cooling system containing a coolant.
[0002] Increasing power output of engines and stricter emission control regulations increases the demands on a vehicle cooling system. The rate of thermal output that can be rejected by a conventional cooling system is essentially determined by parameters such as the size of the surface of a cooler, heat transmission coefficients, flow velocities of the coolant, and by temperature differences of the associated media (surroundings, coolant, etc.). In agricultural vehicles, particularly in tractors, the thermal output of conventional cooling systems is determined generally by the size of the available space of the configuration and the maximum allowable temperature difference. For a water-based cooling system, cooling this maximum temperature difference is a result of the maximum surrounding temperature and the highest allowable cooling water temperature.
[0003] Various cooling systems are known which achieve more efficient cooling with maximum prevailing temperature differences. For example, published German patent application DE 198 54 544 describes a cooling system for a supercharged engine with an improved cooling capacity. This cooling system includes a high temperature cooling circuit and a low temperature cooling circuit. The high temperature cooling circuit includes in a main branch, the engine, a high temperature re-cooler, and a branch circuit with a high temperature charge air cooler. The low temperature cooling circuit includes a low temperature re-cooler in series with a low temperature charge air cooler. Furthermore, this system also includes an engine oil/gearbox oil heat exchanger and a heat exchanger for cooling electronic components. Thus, the heat rejected in the engine oil/gearbox oil heat exchanger is rejected at a relatively high temperature level, while the electronic components and the charge air is cooled simultaneously at a lower temperature. However, this cooling system is costly, and the resulting temperature levels are not appropriate for the cooling of a supercharged engine of an agricultural tractor.
[0004] Other cooling systems are known that are based on the principle of the sorption cooling, in which cold is primarily generated from heat. Such systems are gaining importance, particularly in connection with air conditioned vehicles. Adsorption and absorption refrigeration machines are described in various publications, for example, Andreas Gassel, “Die Adsorptionskaeltemaschine-Betriebserfahrungen und thermodynamische Berechnung”-“The adsorption refrigeration machine—Operating experience and thermodynamic calculations”; Article draft for Ki air and refrigeration technology or York International “Prinzip Absorptionskaltemaschine”-“Principles of absorption refrigeration machine”, prospectus KK14300). DE 199 27 879 A1 describes a vehicle air conditioning system with an adsorption refrigeration arrangement. The system includes an adsorption refrigeration arrangement in which liquid refrigerant is evaporated, in order to extract the heat required for it from a liquid or gaseous medium for the generation of low temperatures. The evaporated refrigerant is conducted to a sorbent to be adsorbed. The sorbent loaded with refrigerant is heated in order to desorb the refrigerant again, and the refrigerant is subsequently liquified in order to make it available for renewed evaporation. Thus, the heat rejected by the engine is used to heat the sorbent. The system includes methanol as refrigerant and activated charcoal as sorbent. However, this absorption refrigeration system is configured for the air conditioning of a vehicle, and appears to be inappropriate for the cooling of individual components of a supercharged engine, particularly that of an agricultural tractor. Furthermore, other potential sources of heat, such as the engine exhaust, cannot be utilized for the high temperatures required for the desorption in the adsorption refrigeration machine disclosed by published German patent application DE 199 27 879 A1 because extensive design-engineering changes would be required.
SUMMARY
[0005] Accordingly, an object of this invention is to provide a cooling system which reduces the thermal load on a conventional main cooling system.
[0006] A further object of the invention is to provide such a cooling system for an engine block or a charge air cooling system.
[0007] These and other objects are achieved by the present invention, wherein a cooling system includes a known sorption cooling system. The sorption cooling system includes an evaporator for evaporating a refrigerant, a sorption chamber containing an absorbent which absorbs the evaporated refrigerant, a desorption chamber for desorption of the refrigerant from the absorbent and a condenser for condensing the refrigerant. To supply the heat required for the desorption, a first exhaust gas stream of the engine is communicated to the desorption chamber. The evaporator provides additional cooling of the coolant of the main cooling system, and/or cools a second exhaust gas stream from the engine. Combining a conventional main cooling system with a sorption cooling system decreases the load on the main cooling system and the evaporator reduces heat rejection. The evaporator is positioned at the cylinder head and directly cools the cylinder head, so that the heat rejected there does not fully load the main cooling system.
[0008] The heat removed by the sorption cooling system or the heat removed by the evaporator can be delivered to the surroundings at a considerably higher temperature level by the condensation of the refrigerant. Thus, higher temperature differences to the surroundings can be realized and hence a more compact configuration of coolers is possible.
[0009] The evaporator can be positioned to extract heat from other components, such as, for example, the engine itself, parts of the mechanical power transmission, components of the power electronic system, electrical machines, the vehicle cab, the charge air, a recirculated exhaust gas stream or any other components that can be cooled contained in or on the vehicle. Moreover, this cooling system can be used to cool fluids such as engine oil or gearbox oil.
[0010] The sorption cooling system extracts heat from the conventional main cooling system, at a cost in thermal output. Preferably, thermal output supplies the power for the sorption cooling system. Thereby in a sorption cooling system a “thermal compressor” is realized in contrast to the mechanically driven compressors which are widely used in refrigeration machines and in air conditioners.
[0011] The thermal output required to drive the sorption cooling system is extracted from the vehicle, preferably from the exhaust gas of the engine. But, other sources of thermal energy are also conceivable. For example, the rejected heat of the engine or the engine cooling water or any other available source of heat in the vehicle could be used.
[0012] The process where a material is taken up selectively by another material is known as absorption or adsorption. When the particular process is unknown, the process is known as sorption. The sorbing material is referred to as a sorbent. The material that is sorbed is the sorbate. “Desorption” is the regeneration or the separation of the material that was sorbed.
[0013] Absorption is the process in which gases are taken up by fluids or solids, wherein the dissolved gas component is the absorbent and the fluid (solvent) is the absorbate. Desorption is the reverse of the absorption, wherein gas is driven off at increased temperature and/or reduced pressure and the solvent is regenerated.
[0014] Adsorption is the deposition of gases and dissolved materials (adsorbate) on the surface of solids (adsorbent), for example, the binding of steam as adsorbate to an activated charcoal adsorbent. Adsorption takes place not only on the outer surface of the absorbent, but also in its pores, as long as these are accessible to the absorbate. During the adsorption process, the heat of adsorption is liberated. The heat of adsorption is approximately of the magnitude of the heat of condensation. Important adsorbents are activated charcoal, silica jell, aluminum oxide or even fullers earth.
[0015] In general, desorption is the reverse of the absorption or adsorption process at higher temperatures or lower pressures where absorbed or the adsorbed material is regenerated.
[0016] An absorption cooling system operates with a liquid solvent as sorbent or absorbent, and an adsorption cooling system operates with a solid sorbent. An absorption cooling system will include an absorbent and an absorbate, such as, for example, a solvent and a refrigerant, where the refrigerant is absorbed by the solvent and is again separated from it in the desorption process. For example, lithium bromide absorbs water, and water absorbs ammonia. The material absorbed functions as a refrigerant (absorbate), while the other material functions as a solvent (absorbent). The refrigerant and the solvent are together characterized as an operating pair. The solution of the materials is heated in order to separated them from each other again in the desorption chamber (boiler or separator). The refrigerant evaporates first because of its lower evaporation temperature. The evaporated refrigerant is freed from the rest of the solvent with which it had been evaporated by means of a liquid separator. Then, the refrigerant is cooled in the condenser (liquefier) and thereby liquified. The pressure of the refrigerant is reduced to an evaporation pressure corresponding to a predetermined temperature by a control valve. In the evaporator the refrigerant is evaporated by absorbing heat, and the heat absorbed provides the cooling effect. Next, the refrigerant vapor is conducted into the sorption chamber. After the separation from the refrigerant (absorbent) or after the desorption, the pressure of the solvent (absorbate) is reduced by a valve to the sorption chamber pressure, cooled and conducted to the sorption chamber. Thereby, the solvent takes up the refrigerant vapor in the sorption chamber. A solvent pump conducts the enriched solution back to the ejector, the circulation is thereby closed. The entire solvent circulation operates as a “thermal compressor”, and functions as a compressor of a compression refrigeration machine. As noted initially, the amount of heat required for the evaporation QO and the amount of heat required for the desorption QH can be derived from differing vehicle components, so that the amount of heat that is to be rejected by the main cooling system is reduced, and that the amount of heat required for the evaporation QO is derived from the main cooling system. ***The system operates more effectively with higher temperature of the cooling water of the main cooling system. The tendency to raise the pressure level in the main cooling circuit in order to attain correspondingly higher allowable temperatures therefore promotes the possibilities of the absorption cooling systems. The driving temperatures for the ejection lie between 90° C. and 140° C., where the medium or the components to be cooled can assume similar temperatures as with the cooling with an adsorption cooling system.
[0017] An adsorption cooling system includes an adsorption chamber filled with a sorbent or an adsorbent, and a desorption chamber filled with an adsorbent, a condenser and an evaporator. As in the case of an absorption cooling system, in an adsorption cooling system various pairs of materials are possible. The adsorbent may be for example, silica gel, and the refrigerant may be adsorbate water. It is also known to use activated charcoal as adsorbent and methanol as adsorbate. The process is discontinuous and closed. During a cycle the following processes occur: The water (adsorbate) adhering to the silica gel (adsorbent) is driven out in the desorption chamber with the supply of an amount of heat QH by a heated water circulation associated with the desorption chamber. The water is liquified in the condenser and heat is carried away by the cooling water circuit associated with the condenser. The condensate is sprayed into the condenser and evaporated under strong negative pressure. An amount of heat QO is extracted from the surroundings or from a component that is to be cooled. The water vapor is adsorbed in the adsorption chamber and the resulting heat of adsorption is conducted to a cooling water circuit associated with the adsorption chamber. By simply reversing the heating and cooling water circuits of the desorption or the adsorption chamber between the two chambers the functions of desorption and adsorption are interchanged at the end of a cycle and the process is started anew.
[0018] The desorption of the adhering water and the generation of pressure for the condensation occurs at low temperatures of 60° C.-70° C., so that this technology can be applied at lower temperatures than with an absorption cooling system.
[0019] Such a sorption cooling system can be driven “at no cost” by heat sources available on the vehicle, for example, the exhaust gas, instead of mechanical power required by compressors. Furthermore, the cooling capacities of a conventional cooling system can be reduced, and the amount of heat that must be removed in a water-to-air heat exchanger from the engine is reduced, thereby reducing the load on the main cooling system, and it is possible to remove heat at a higher temperature than in a conventional cooling system. Moreover, the energy required for cooling of further components can be minimized and fuel consumption can be reduced. In addition, it is possible to use environmentally benign refrigerants. Furthermore, if an air conditioning installation exists, mechanical or electrical compressor drive units can be omitted or their size reduced. Furthermore, various fluids and tractor components can be cooled to temperatures below the temperature of the surroundings. In contrast to a cooling system with a compressor, fewer moving parts are required, and hence fewer components are subject to wear. Beyond that, the exhaust back pressure is not increased with the heat exchanger outside at the exhaust pipe of the vehicle.
[0020] In a preferred embodiment of the invention, a first exhaust gas stream of the engine is an exhaust gas stream of an exhaust gas recirculation system, so that the heat required for desorption is extracted from the vehicle exhaust gas recirculation system. This advantageously cools the recirculated exhaust gas, and when the recirculated exhaust gas reaches the engine combustion chamber it results in a reduced heating of the charged air and thereby an improved charging or improved emission values can be obtained during the combustion.
[0021] In another embodiment, the first exhaust gas stream is branched off from the main exhaust gas stream delivered to the environment. Thus, the heat of an exhaust gas stream can be used to drive the desorption chamber, thereby improving the total energy balance of the vehicle.
[0022] In a further embodiment, the main cooling system is a charge air cooling system and that the evaporator of the sorption cooling system is used for additional cooling of the charge air cooling system. Thus, the charge air cooling system can be configured more efficiently, or the cooling performance for the charge air can be improved so that an increased amount of charge air reaches the engine combustion chamber. This improves emission values.
[0023] In a further embodiment, the main cooling system is an engine block cooling system and that the evaporator of the sorption cooling system is used for additional cooling of the engine block cooling system. This reduces the load on the main engine cooling system. This can be utilized either to reduce the required cooler volume or, if necessary, to increase the entire cooling capacity.
[0024] In a further embodiment, the main cooling system is an air conditioner cooling system and that the evaporator of the sorption cooling system is used for additional cooling of the cab air flow. This permits a reduced size of the air conditioner compressor, and less mechanical energy needs to be drained away from the vehicle. This, in turn, leads to an improved total energy balance of the vehicle and hence a lower fuel consumption.
[0025] In a further embodiment, the second exhaust gas stream is an exhaust gas stream of an exhaust gas recirculation system, where the evaporator of the sorption cooling system cools the exhaust gas in the exhaust gas recirculation system. Thus, the heat of the exhaust gas is used to drive the desorption chamber, thus improving the total energy balance of the vehicle. Another advantage is that the recirculated exhaust gas is cooled, and upon the recirculation of the exhaust gas into the engine combustion chamber, heating of the charge air is reduced, thereby improving air charge or emissions during the combustion.
[0026] Preferably, the condenser is connected with a cooler, which carries away the heat liberated in the condenser. The amount of heat generated by condensing the refrigerant (sorbent) can thereby be efficiently delivered to the surroundings, and heat is transferred at a higher temperature.
[0027] In another embodiment of the invention, the sorption chamber is connected with a cooler which carries away the heat liberated in the sorption chamber. Thereby the amount of heat generated by the sorption of the refrigerant (sorbent) can be efficiently delivered to the surroundings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 is a schematic block diagram of a cooling system according to the invention with a sorption cooling system to reduce the load on a charge air cooling circuit;
[0029] FIG. 2 is a schematic block diagram of a sorption cooling system which reduces the load on the charge air cooling system;
[0030] FIG. 3 is a schematic block diagram of a cooling system according to the invention with a sorption cooling system which reduces the load on the cooling circuit for an internal combustion engine;
[0031] FIG. 4 is a schematic block diagram of a cooling system according to the invention with a sorption cooling system which cools an exhaust gas recirculation system; and
[0032] FIG. 5 is a schematic block diagram of a cooling system according to the invention with a sorption cooling system which reduces the load on a cab air cooling system.
DETAILED DESCRIPTION
[0033] FIG. 1 shows a cooling system 10 for an internal combustion engine 12 with a charge air system 14 , a charge air cooling system 16 , an engine cooling system 18 , an exhaust gas recirculation system 20 , and a sorption cooling system 22 . The sorption cooling system 22 is applied in order to reduce the load on the charge air cooling system 16 .
[0034] The engine 12 includes an intake system 24 which is supplied with super charged and cooled air 26 and recirculated exhaust gas 28 . The recirculated exhaust gas 28 is withdrawn from the exhaust gas stream 30 flowing out of the engine 12 and conducted to the intake system 24 of the engine 12 . By means of the exhaust gas recirculation system 20 , the amount of the exhaust gas delivered to the surroundings can be reduced and the emissions reduced.
[0035] In order to cool the engine 12 , the engine cooling system 18 is connected to the engine 12 over coolant lines 32 . The coolant lines 32 are connected with an engine cooler 34 , so that a coolant (not shown) in the coolant lines 32 circulates between the engine cooler 34 and the engine 12 and carries away heat generated in the engine 12 to the engine cooler 34 .
[0036] The charge air system 14 is used, among other uses, to compress the intake air taken in from the surroundings so that an increased amount of air flows into the intake system 24 of the engine 12 , resulting in improved combustion of the fuel and thereby reducing emissions in the exhaust gas. The charge air system 14 includes an air filter 36 that filters intake air taken in from the surroundings and from which the filtered intake air is conducted into a turbo-supercharger 38 . The turbo-supercharger 38 includes a drive side (not shown) and a compressor side (not shown). The drive side of the turbo-supercharger 38 is driven by a drive exhaust gas stream 40 , where the drive exhaust gas stream 40 is also branched off from the exhaust gas stream 30 . The intake air from the air filter 36 is compressed in the compressor side of the turbo-supercharger 38 . This compression increases the density of the intake air and increases the heat of the intake air. This heat, in turn, has a negative effect on the combustion of the fuel, for which reason the charge air system 14 as a rule is also connected to a charge air cooling system 16 . The charge air cooling system 16 includes a charge air cooler 42 which is connected over charge air coolant lines 44 with a heat exchanger 46 . The heat exchanger 46 is positioned between the turbo-supercharger 38 and the intake system 24 so that a coolant (not shown) in the charge air coolant lines 44 circulates between the heat exchanger 46 and the charge air cooler 42 and cools a flow of heat coming from the compressed charge air on the charge air cooler 42 .
[0037] According to FIG. 1 , the sorption cooling system 22 includes a desorption chamber 48 arranged in the recirculated exhaust gas stream 28 , a condenser 50 associated with the desorption chamber 48 , a condenser cooler 54 connected by condenser coolant lines 52 for removing the heat liberated in the condenser, an evaporator 56 arranged at the charge air coolant lines 44 , and a sorption chamber 58 with a sorption chamber cooler 62 connected by sorption chamber coolant lines 60 for removing the heat liberated in the sorption chamber 58 .
[0038] At least some components similar to those shown in FIG. 1 and with the same reference numbers are also included in FIGS. 2-5 .
[0039] FIG. 2 illustrates the principle of operation of a cooling system wherein the sorption cooling system 22 reduces the load on the charge air cooling system 16 . Several components shown in FIGS. 1 and 3 - 5 are omitted from FIG. 2 to better illustrate the operation of the cooling system 10 .
[0040] The sorption cooling system 22 of FIG. 2 includes a solvent circulation circuit 64 and a refrigerant circuit 66 . The solvent circuit 64 includes the desorption chamber 48 driven by the recirculated exhaust gas stream 28 , a first control valve 68 , the sorption chamber 58 and a solvent pump 70 . The refrigerant circuit 66 includes the desorption chamber 48 driven by the recirculated exhaust gas stream 28 , the condenser 50 , a second control valve 72 , the evaporator 56 and the sorption chamber 58 . Furthermore, the condenser 50 and the sorption chamber 48 are each connected with a cooler 54 , 62 which delivers the thermal output to be carried away from the condenser 50 or the sorption chamber 58 to the surroundings. To reduce the load on the charge air cooling system 16 , the evaporator 56 of the sorption cooling system 22 is integrated into the charge air cooling circuit 74 of the charge air cooling system 16 .
[0041] The cooling system 10 includes a two-material mixture (not shown) in the solvent circuit 64 , which is located in the supply line 76 directed at the desorption chamber 48 . The two-part mixture in the supply line 76 consists of a solvent (not shown) which is mixed with a refrigerant (not shown) for cooling and circulating in the refrigerant circuit 66 or which has sorbed this in the sorption chamber 58 . The two-part mixture is conveyed by the solvent pump 70 into the desorption chamber 48 . In the desorption chamber 48 the two-part mixture is heated by the heat from the recirculated exhaust gas stream 28 . The refrigerant taken up by the solvent has a lower evaporation temperature than the solvent, so that the refrigerant evaporates before the solvent evaporates. This causes the desorption of the refrigerant out of the solvent. The refrigerant vapor desorbed in the desorption chamber 48 or driven out, flows through a first connecting line 78 into the condenser 50 . The refrigerant vapor is liquified in the condenser 50 where the thermal flow is carried away at a higher temperature level compared to a conventional cooling system and with a higher temperature difference between the condenser cooler 54 and condenser 50 . The condensed or cooled refrigerant flows into the evaporator 56 over a supply line 80 controlled by the second control valve 72 . The refrigerant is evaporated in the evaporator while taking up heat from the charge air cooling system 16 . Heat is thereby effectively withdrawn from the charge air cooling system 16 by the evaporator 56 or by the heat taken up by the refrigerant. Thus the cooling system 10 reduces the load on the charge air cooling system 16 , thereby either improves the cooling capacity of the charge air cooling system 16 or reduces the dimensions of the charge air cooling system 16 .
[0042] The refrigerant vapor flowing out of the evaporator 56 flows into the sorption chamber 58 . The solvent circulating in the solvent circuit flows over the first control valve 68 into the sorption chamber 58 and is available to take up the refrigerant vapor or for the sorption of the refrigerant vapor. In the sorption chamber the refrigerant vapor is taken up by the solvent or it is sorbed, thereby generating heat of solution that is carried away over the sorption cooler 62 . The refrigerant flowing out of the evaporator that has not been evaporated or is still liquid is conducted over a further supply line 82 over the desorption chamber 48 and driven into the condenser 50 . Thereby, both circuits are closed, that is, the refrigerant circuit 66 and the solvent circuit 64 are closed. The improved cooling performance relative to the charge air on the basis of lower combustion temperatures in the intake system 24 of the engine 12 improves emissions.
[0043] The cooling system 10 and the sorption cooling system 22 of FIG. 2 can also reduce the load on other main cooling systems or even for the cooling of the recirculated exhaust gas 48 . This is shown in FIGS. 3-5 .
[0044] In a second embodiment shown in FIG. 3 , the evaporator 56 is integrated into the engine cooling system 18 . In this embodiment the heat removal of the engine cooling system 18 or the reduction of the load on the engine cooling system 18 is performed in the same way by the evaporator 56 , as is the case with the reduction of the load on the charge air cooling system 16 of FIG. 1 or 2 . In the FIG. 3 embodiment a separate exhaust gas stream 84 is branched off from the main exhaust gas stream 30 in order to drive the desorption chamber. The embodiment shown in FIGS. 1 and 2 is also conceivable, in which the desorption chamber 48 is driven by the recirculated exhaust gas stream 28 as is shown in FIG. 3 with a desorption chamber 48 ′ driven by a recirculated exhaust gas stream. Furthermore, an embodiment is conceivable even without the charge air cooling system 16 and without the exhaust gas recirculation system 20 . Similar to the charge air cooling system 16 of FIGS. 1 and 2 , the FIG. 3 embodiment reduces the load on the engine cooling system 18 , either by increasing the cooling capacity of the engine cooling system 18 or by reducing the size of the engine cooling system 18 .
[0045] In the further embodiment of FIG. 4 , the sorption cooling system 10 can be used to cool the recirculated exhaust gas stream 28 , to improve combustion performance of the engine 12 and thereby reduce the load on the engine cooling system 18 and the charge air cooling system 16 , or improve the entire energy balance of the engine 12 . If the recirculated exhaust gas stream 28 is conducted without any cooling into the intake system 24 of the engine 12 , the charge air that was previously cooled by the charge air cooling system 16 is heated. This worsens emission performance of the engine 12 . The evaporator 56 of FIG. 4 is integrated into the exhaust gas recirculation system 20 and heat is withdrawn from the recirculated exhaust gas stream 28 during the evaporation of the refrigerant in the evaporator 56 . According to FIG. 4 , as is also shown in FIG. 3 , the separated exhaust gas stream 84 is also used to drive the desorption chamber 48 .
[0046] In a further embodiment shown in FIG. 5 , the evaporator 56 is integrated into an air conditioning cooling system (not shown). In this way a cab air stream 86 pre-cooled by a conventional, mechanically driven compressor (not shown), can be post-cooled or, in a reverse arrangement, also pre-cooled by the evaporator 56 and post-cooled by the compressor. The other components of the cooling system of FIG. 5 can be arranged similarly to the embodiments of FIGS. 1-4 . The reduced load on the air conditioning system by the desorption cooling system leads to smaller mechanically driven compressor and thereby reduces energy requirements for the air conditioning system.
[0047] The sorption cooling systems of FIGS. 1-5 can also be combined with each other. For example, several evaporators can be arranged in a parallel or a series circuit and used to cool the charge air, the recirculated exhaust gas, 58 , the engine cooling water and/or the cab air stream 86 .
[0048] While the present invention has been described in conjunction with a specific embodiment, it is understood that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, this invention is intended to embrace all such alternatives, modifications and variations which fall within the spirit and scope of the appended claims. | A cooling system for an agricultural vehicle, such as a tractor driven by an internal combustion engine includes a main cooling system containing a coolant. The cooling system includes a sorption cooling system which includes an evaporator for evaporating a refrigerant, a sorption chamber for the sorption of the refrigerant vapor, a desorption chamber for the desorption of the refrigerant from the sorbent, and a condenser for condensing the refrigerant. An exhaust gas stream from the engine is conducted to the desorption chamber to provide the heat necessary for the desorption. The evaporator is used for additional cooling of the coolant of the main cooling system and/or for cooling a second exhaust gas stream from the engine. | 8 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a dielectric ceramic composition which is widely used in high frequency electronic components, more particularly, to a low-temperature cofired dielectric ceramic composition with a high dielectric constant and a low dielectric loss.
2. Description of the Prior Art
For use in a high frequency range (˜2 GHz), chip type components such as LC filters, require that their electrodes be high in electrical conductivity. Ag or Cu is selected for internal electrode due to their high electrical conductivity. Ag and Cu have melting points of 961° C. and 1,083° C., respectively, which are both much lower than those of Ni (1,455° C.) or Ag—Pd.
Dielectric material must have lower sintering temperatures than the melting point of the internal electrode. In the case that Ag or Cu is employed as electrodes, available dielectric materials can be therefore selected from only a narrow range.
Generally, LTCC materials using Ag as an internal electrode are composed mainly of glass frit in combination with ceramic fillers for improving strength and dielectric properties. And its sintering temperature is about 900° C. or lower.
However, such compositions are, for the most part, found to have dielectric constants of 10 or less, which are too low to apply the compositions for LC filters. For use in LC filters, dielectric compositions are required to show a high dielectric constant, a low dielectric loss (high Q value), and a stable temperature coefficient of resonant frequency.
For instance, dielectric ceramic compositions with high dielectric constants allow the reduction of the size of the electrodes, making it possible to miniaturize devices. Additionally, such dielectrics are very useful in reducing insertion loss. Further, stable temperature coefficients of resonant frequency are helpful in stabilizing high-temperature properties of dielectrics.
Development of LTCC materials with high dielectric constants has largely been investigated in two manners: one is to develop new systems that can be sintered at 900° C. or lower; the other is directed to composite systems comprising low-temperature sintering aids or glass frit on the basis of conventional dielectric materials of high dielectric constants.
Usually, the former is Bi-based systems. These systems, however, have difficulty in being used in practice due to reactivity with electrodes, and poor reproducibility.
In association with the latter, there is known a technique in which a CaO—Sm 2 O 3 —Nd 2 O 3 —Li 2 O—TiO 2 composition (K. H. Yoon et. al., Jpn. J. Appl. Phys., 35[9B] 5145 (1996)) with a sintering temperature of 1,300° C. or higher is combined with the sintering aid B 2 O 3 —Li 2 O to reduce the sintering temperature to 1,100° C. However, 1,100° C. is still too high to conduct the co-firing of Ag electrodes.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to overcome the above problems encountered in prior arts and provide a dielectric ceramic composition which exhibits high dielectric constant and low dielectric loss and can be cofired with Ag electrode.
It is another object of the present invention to provide a dielectric ceramic composition which is improved in sintering properties as well as being controllable in high frequency dielectric properties.
In accordance with an aspect of the present invention, there is provided a dielectric ceramic composition represented by the following chemical formula 1:
Chemical Formula 1
a wt. % { x CaO- y 1 Sm 2 O 3 - y 2 Nd 2 O 3 - w Li 2 O- z TiO 2 }+b wt. % (ZnO—B 2 O 3 —SiO 2 based or Li 2 O—B 2 O 3 —SiO 2 based glass frit)
wherein, 13.0 mol %≦x≦20.0 mol %; 10.0 mol %≦y 1 +y 2 ≦17.0 mol %; 6.0 mol %≦w≦11.0 mol %; 60.0 mol %≦z≦67.0 mol % with the proviso that x+y 1 +y 2 +w+z=100; 85.0 wt. %≦a≦97.0 wt. %; 3.0 wt. %≦b≦15.0 wt. %.
In accordance with another aspect of the present invention, there is provided a dielectric ceramic composition represented by the following chemical formula 2:
Chemical Formula 2
a wt. % { x CaO- y 1 Sm 2 O 3 - y 2 Nd 2 O 3 - w Li 2 O- z TiO 2 }+b wt. % (ZnO—B 2 O 3 —SiO 2 based or Li 2 O—B 2 O 3 —SiO 2 based glass frit)+ c wt. % CuO
wherein, 13.0 mol %≦x≦20.0 mol %; 10.0 mol %≦y 1 +y 2 ≦17.0 mol %; 6.0 mol %≦w≦11.0 mol %; 60.0 mol %≦z≦67.0 mol % with the proviso that x+y 1 +y 2 +w+z=100; 85.0 wt. %≦a≦97.0 wt. %; 3.0 wt. %≦b≦15.0 wt. %; and c≦7.0 wt. %.
DETAILED DESCRIPTION OF THE INVENTION
Based on CaO—Sm 2 O 3 —Nd 2 O 3 —Li 2 O—TiO 2 with low dielectric loss and high dielectric constant, the dielectric ceramic composition of the present invention comprises ZnO—B 2 O 3 —SiO 2 or Li 2 O—B 2 O 3 —SiO 2 glass frit as a sintering aid, thereby being able to be cofired with Ag electrode patterns in addition to exhibiting a high dielectric constant and low dielectric loss.
To the composition, CuO may be further incorporated. In the dielectric composition, CuO acts as a sintering aid to improve the densification of the composition, and plays a role in controlling dielectric properties at high frequencies.
As described above, the ceramic composition of CaO—Sm 2 O 3 —Nd 2 O 3 —Li 2 O—TiO 2 , although superior in terms of dielectric loss and dielectric constant, cannot be cofired with Ag electrodes because it can be sintered at 1,300° C. which is much higher than the melting point of Ag (961° C.).
In accordance with the present invention, the base ceramic composition CaO—Sm 2 O 3 —Nd 2 O 3 —Li 2 O—TiO 2 is modified in the molar ratio of its constituting ingredients, and is incorporated with a certain amount of glass frit so as to make it possible to co-fire the ceramic composition with the Ag electrode. For use in the present invention, the base ceramic composition CaO—Sm 2 O 3 —Nd 2 O 3 —Li 2 O—TiO 2 comprises CaO (x) in an amount of 13˜20 mol %, Sm 2 O 3 and Nd 2 O 3 (y 1 +y 2 ) in an amount 10˜17 mol %, Li 2 O (w) in an amount of 6˜11 mol %, and TiO 2 (z) in an amount of 60˜67 mol %, with the proviso that x+y1+y2+w+z=100.
When CaO is used at less than 13 mol %, the composition has a large negative TCF value. On the other hand, the TCF of the composition is excessively increased in the positive direction at more than 20 mol % of CaO. Therefore, the compositions containing less than 13 mol % or more than 20 mol % of CaO cannot be used in practice. For practical uses in TCF value, that is, in the range of ±20 ppm/° C., CaO is preferably used in an amount of 13 ˜20 mol %.
With the sum of Sm 2 O 3 and Nd 2 O 3 (y 1 +y 2 ) amounting to 10 mol %, the base ceramic composition shows too large a positive TCF. On the other hand, more than 17 mol % of the sum of Sm 2 O 3 and Nd 2 O 3 causes an increase in dielectric loss and thus deteriorates the Q value. For these reasons, the sum of Sm 2 O 3 and Nd 2 O 3 is preferably defined in the range of 10˜17 mol %. For example, in the presence of too small amounts of Sm 2 O 3 and Nd 2 O 3 , a CaTiO 3 phase that is as high as +300 ppm/° C. in TCF is formed, giving rise to an excessive increase in the TCF of the composition. On the other hand, more than 17 mol % of Sm 2 O 3 and Nd 2 O 3 in sum, an Sm 2 Ti 2 O 7 phase is formed as a secondary phase which leads to drastically decreasing the Q value.
Below 6 mol % of Li 2 O, there is formed Sm 2 Ti 2 O 7 which negatively affects the Q f value. On the other hand, when the content of Li 2 O is over 11 mol %, the base ceramic composition is excessively increased in TCF. Accordingly, the preferable amount of Li 2 O falls within the range of 6-11 mol %.
In the present invention, a glass frit composition is used to lower the sintering temperature of the base dielectric composition to such an extent as to fire the composition together with electrodes made of low-melting point metal such as Ag.
Useful in the present invention is the glass frit based on ZnO—B 2 O 3 —SiO 2 —PbO or Li 2 O—BaO—B 2 O 3 —SiO 2 .
Preferably, the ZnO—B 2 O 3 —SiO 2 —PbO based glass frit comprises ZnO in an amount of 30˜70 wt %, B 2 O 3 in an amount of 5˜30 wt %, SiO 2 in an amount of 5˜40 wt %, and PbO in an amount of 2˜40 wt %.
B 2 O 3 lowers the viscosity of the glass and accelerates the densification of the dielectric ceramic composition of the present invention. Where B 2 O 3 is used in an amount lower than 5 wt. %, the dielectric ceramic composition is likely to not be sintered at lower than 900° C. With more than 30 wt % of B 2 O 3 , the dielectric ceramic composition has poor moisture resistance. Thus, its amount is preferably on the order of 5˜30 wt. % of the glass frit.
More than 40 wt % of SiO 2 results in an excessive increase in the softening temperature of the glass frit which therefore cannot act as a sintering aid. When SiO 2 is present in an amount less than 5 wt %, its effect is not obtained. That is, a preferable amount of SiO 2 falls within the range of 5-40 wt. %.
With less than 2 wt % of PbO, the glass frit has too high a softening temperature (Ts), making no contribution to the sintering of the dielectric ceramic composition. On the other hand, more than 40 wt. % of PbO lowers the Ts of the glass frit to improve the densification of the composition, but has the problem of decreasing Q value. Considering these facts, the amount of PbO in the glass frit is defined in the range of 2˜40 wt %.
It is preferred that ZnO is used in an amount of 30˜70 wt %. Excessive amounts of ZnO lead to an increase in the softening temperature of the glass frit, making the low temperature firing impossible.
In the case of the Li 2 O—BaO—B 2 O 3 —SiO 2 based glass frit, it preferably comprises Li 2 O in an amount of 1—10 wt %, BaO in an amount of 10˜40 wt %, B 2 O 3 in an amount of 20˜50 wt %, and SiO 2 in an amount of 15˜40 wt %.
For the same reasons as in the ZnO—B 2 O 3 —SiO 2 —PbO based glass frit, contents of B 2 O 3 and SiO 2 are limited in the Li 2 O—BaO—B 2 O 3 —SiO 2 based glass frit, but somewhat differ from those in the ZnO—B 2 O 3 —SiO 2 —PbO based glass frit.
Functioning to lower the softening temperature (Ts) of the glass frit to improve the densification of the dielectric ceramic composition, Li 2 O is used in an amount of up to 10 wt. %: otherwise, the composition is poor in moisture resistance.
When being subjected to low temperature sintering in the presence of the glass frit containing more than 40 wt % of BaO, the dielectric ceramic composition is drastically decreased in Q value. At less than 10 wt % of BaO, the softening temperature of the glass frit is increased, deteriorating the sinterability of the composition. Thus, the amount of BaO is preferably defined within the range of 10˜40 wt % of the glass frit.
As for the amount of the glass frit, it is preferably on the order of 3˜15 wt % based on the total weight of the composition. For example, when too little glass frit is used, sintering is not performed on the composition, which therefore becomes small in dielectric constant. On the other hand, when too much glass frit is used, a decrease is brought about in both dielectric constant and Q value.
In accordance with another embodiment of the present invention, CuO is used in the dielectric ceramic composition of the present invention to improve the densification and to control the dielectric properties. In cooperation with the glass frit, CuO acts as a sintering aid to increase the dielectric constant. Also, CuO plays a role in controlling the temperature coefficient of frequency without a large change in Q value. It is preferably used in an amount of 7 wt % or less. More than 7 wt % of CuO causes a decrease in dielectric constant and Q value, rather than improving the densification of the composition. More than solubility limit in the dielectric, CuO forms a secondary phase at the interface.
Below, a description will be given of the preparation of the dielectric ceramic composition of the present invention.
The starting materials CaCO 3 , Sm 2 O 3 , Nd 2 O 3 , Li 2 CO 3 and TiO 2 , each with a purity of 99.0% or higher, are weighed according to a desired composition of x CaO−y 1 Sm 2 O 3 −y 2 Nd 2 O 3 −w Li 2 O−z TiO 2 , and admixed in a wet manner.
In this regard, the wet mixing is carried out by milling the starting materials in deionized water for about 16 hours with the aid of 3φ zirconia balls in a rod mill.
The slurry thus obtained is dried and calcined. Preferably, the calcination is carried out at 1,000-1,150° C. for about 2 hours at the heating rate of 5° C./min. When the calcination temperature is lower than 1,000° C., much Sm 2 TiO 7 remains as an intermediate phase, giving rise to a decrease in Q value after sintering. At higher than 1,150° C., on the other hand, the powders become too coarse to pulverize later.
After being weighed according to a desired composition, the glass frit components are melted at 1,200-1,400° C., quenched in water, and dry-pulverized. Then, the coarse particles are finely pulverized into powder with a particle size of 0.5˜1.0 μm in ethyl alcohol.
The base dielectric ceramic composition is admixed with the glass frit powder composition, together with appropriate amounts of CuO in a batch, after which the admixture is pulverized.
Following drying, the powder thus obtained was subjected to secondary calcinations at 600-700° C. The secondary calcination temperature, which is somewhat higher than the softening temperature (Ts) of the glass frit, makes the dielectric homogenous with the glass frit, thereby improving the uniformity of the dielectric ceramic composition after the sintering.
Next, the calcined powder is further broken down into a desired particle size, mixed with a binder, and molded to a desired form such as a disc or a sheet.
Afterwards, the electrode in a form of disc or sheet is calcined and co-fired at less than 900° C. to produce a desired device.
Having generally described this invention, an improved understanding can be obtained by reference to certain specific examples which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified.
EXAMPLE 1
CaCO 3 , Sm 2 O 3 , Nd 2 O 3 , Li 2 CO 3 , and TiO 2 were weighed according to the composition of x CaO−y 1 Sm 2 O 3 −y 2 Nd 2 O 3 −w Li 2 O−z TiO 2 ZrO 2 , as given in Table 1, below, and admixed in deionized water for 16 hours in the presence of 3φ zirconia balls using a rod mill.
The slurry thus obtained was dried, roughly pulverized in a mortar, and heated at the rate of 5° C./min to a temperature of 1,000-1,150° C. at which calcination was carried out for 2 hours.
Subsequently, the calcined powder was pulverized first in a mortar and then by use of a planetary mill at 200 rpm for 30 min. After being combined with a binder, the pulverized powder was molded into a disc by uniaxial compression at a pressure of 2.0 ton/cm 2 using a 14 mmφ mold. The specimen was sintered at 1,300° C. for 3 hours and measured for dielectric constant (K), Q value, and TCF. The results are given in Table 1, below.
In Table 1, the dielectric constant (K) and Q value were measured by the Hakki & Coleman method while the temperature coefficient of resonant frequency (TCF) was measured by the cavity method. TCF was determined between 20 and 85° C. In this regard, the specimen was measured for resonant frequency after being maintained at 20° C. for 30 min, and then heated to and maintained at 85° C. for 30 min prior to re-measurement for resonant frequency. With the measurements, the TCF was determined.
TABLE 1
Compo-
sition
No.
CaO
Sm 2 O 3
Nd 2 O 3
Li 2 O
TiO 2
K
Q
TCF
1
11.0
15.0
0.0
8.0
66
81.0
3000
−60.0
2
21.0
5.0
5.0
8.0
61.0
120
4500
50.0
3
19.6
9.8
0.0
8.8
61.8
123
4350
65.0
4
6.7
17.5
0.0
8.4
67.4
75
500
−85.0
5
19.0
11.0
0.0
5.9
64.1
110.5
450
32.0
6
11.5
9.5
4.5
11.5
63.0
130
1300
75.0
7
15.8
13.2
0.0
7.9
63.1
105
5500
15.0
8
18.0
11.8
0.0
7.8
62.4
105.3
5604
13.3
9
16.9
4.8
7.9
7.8
62.6
113.2
3750
12.6
As shown in Table 1, the base ceramic composition according to the present invention (Nos. 7-9) have dielectric constants higher than 70 in addition to exhibiting a Q value of 500 or higher and a TCF of ±20 ppm/° C.
EXAMPLE 2
After composition Nos. 7 and 8 of Table 1 were roughly pulverized in respective mortars, 2.0˜17.0 wt % of the glass frit was added, along with 0˜8.0 wt % of CuO, to 30 g of each composition as shown in Table 4, below, in a batch. Thereafter, the admixture was pulverized again and mixed homogeneously.
The glass frit was prepared by weighing its components according to the compositions of Tables 2 and 3, melting them at 1,200˜1,400° C., quenching the molten glob in water, dry-pulverizing it to coarse particles, and milling them to a size of 0.5˜1.0 μm in ethyl alcohol.
Next, the admixture was dried, and calcined at 600-700° C. for 2 hours.
Subsequently, the calcined powder was pulverized first in a mortar and then milled for 30 min by use of a planetary mill at 200 rpm.
After being combined with a binder, the pulverized powder was molded into a disc by uniaxial compression at a pressure of 2.0 ton/cm 2 using a 14 mmφ mold. The specimen was sintered at 900° C. for 3 hours and measured the dielectric constant (K), Q value, TCF and sintered density. The results are summarized in Table 4, below.
In Table 4, comparison 2 and 13 were prepared by sintering comparison 1 and 5 at 1,050° C., respectively. Also, the samples were analyzed for sintered state and the results are summarized in Table 5.
Dielectric properties, including dielectric constant (K), Q value, and TCF, were measured in the same manner as in Example 1.
TABLE 2
Glass Frit No.
B 2 O 3
SiO 2
ZnO
PbO
Example G1
20
10
55
15
Comparative G2
3
27
60
10
Comparative G3
35
20
40
5
Comparative G4
20
3
55
22
Comparative G5
15
45
35
5
Comparative G6
20
30
49
1
Comparative G7
10
15
32
43
Comparative G8
12
10
75
3
TABLE 3
Glass Frit No.
SiO 2
BaO
B 2 O 3
Li 2 O
Example G9
30
25
40
5
Comparative G10
20
20
55
5
Comparative G11
40
32
19
9
Comparative G12
11
38
42
9
Comparative G13
45
20
30
5
Comparative G14
25
29
45.5
0.5
Comparative G15
16
25
45
14
Comparative G16
15
45
35
5
Comparative G17
38
8
49
5
TABLE 4
Base
Composition
Glass Frit
Dielectric
Dielectric
Amount
Amount
CuO
Constant
TCF
No.
Kind
(wt %)
Kind
(wt %)
(wt %)
(k)
Q
(ppm/° C.)
Note
Comparative 1
7
98.0
G1
2.0
0
—
—
—
1 P. S.
Comparative 2
7
98.0
G1
2.0
0
95
1500
12.5
Sintered
Example 1
7
97.0
G1
3.0
0
70
700
11.0
Sintered
Example 2
7
95.0
G1
3.0
2.0
80
800
4.0
Sintered
Example 3
7
93.0
G1
7.0
0
74
650
8.0
Sintered
Example 4
7
86.0
G1
14.0
0
70
600
7.5
Sintered
Comparative 3
7
83.0
G1
17.0
0
55.2
200
8.0
Sintered
Example 5
7
92.0
G1
7.0
1.0
77.5
960
6.5
Sintered
Comparative 4
7
89.0
G1
3.0
8.0
55
250
9.0
Sintered
Comparative 5
7
90.0
C. G2
10.0
0.0
—
—
—
2 N. S.
Comparative 6
7
90.0
C. G3
10.0
0.0
73
550
8.6
3 P.M.R.
Comparative 7
7
90.0
C. G4
10.0
0.0
—
—
—
2 N. S.
Comparative 8
7
90.0
C. G5
10.0
0.0
—
—
—
2 N. S.
Comparative 9
7
90.0
C. G6
10.0
0.0
—
—
—
2 N. S.
Comparative 10
7
90.0
C. G7
10.0
0.0
69
100
8.3
Poor Q
Comparative 11
7
90.0
C. G8
10.0
0.0
—
—
—
2 N. S.
Comparative 12
8
98.0
G9
2.0
0
—
—
—
2 N. S.
Comparative 13
8
98.0
G9
2.0
0
90
1400
11.5
Sintered
Example 6
8
97.0
G9
3.0
0
75
900
10.0
Sintered
Example 7
8
95.0
G9
3.0
2.0
84
990
8.0
Sintered
Example 8
8
93.0
G9
7.0
0
76
800
8.0
Sintered
Example 9
8
86.0
G9
14.0
0
65
550
4.5
Sintered
Comparative 14
8
83.0
G9
17.0
0
58.5
150
−2.0
Sintered
Example 10
8
92.0
G9
7.0
1.0
79.5
960
6.5
Sintered
Comparative 15
8
89.0
G9
3.0
8.0
50
180
5.0
Sintered
Comparative 16
8
87.0
C.
13.0
0.0
75.1
780
7.5
3 P.M.S.
G10
Comparative 17
8
87.0
C.
13.0
0.0
—
—
—
1 P. S.
G11
Comparative 18
8
87.0
C.
13.0
0.0
—
—
—
1 P. S.
G12
Comparative 19
8
87.0
C.
13.0
0.0
—
—
—
1 P. S.
G13
Comparative 20
8
87.0
C.
13.0
0.0
—
—
—
1 P. S.
G14
Comparative 21
8
87.0
C.
13.0
0.0
68
570
6.2
3 P.M.S.
G15
Comparative 22
8
87.0
C.
13.0
0.0
72
120
5.8
Poor Q
G16
Comparative 23
8
87.0
C.
13.0
0.0
—
—
—
1 P. S.
G17
1 poorly sintered
2 not sintered
3 poor moisture resistance
In addition to being sintered at as low as 900° C. the dielectric ceramic compositions 1˜10 of the present invention, as shown in Table 4, have a dielectric constant of 70 or higher, a Q value of 500 or higher, and a TCF of ±20.0 ppm/° C.
In contrast, the comparative compositions 1˜23 are not sintered at 900° C. or, even if sintered, show poor dielectric properties, including dielectric constant, Q value and TCF.
As mentioned above, the addition of glass frit and CuO to the base composition which is sinterable at 1,300° C. or higher makes it possible for the dielectric ceramic composition of the present invention to be cofired with Ag electrodes at as low as 900° C. Thus the dielectric ceramic compositions exhibit a dielectric constant of 60 or higher, a Q value of 500 or higher (at 3 GHz), and a TCF of ±20.0 ppm/° C., so that they are suitable for use in multilayered LC filters.
The present invention has been described in an illustrative manner, and it is to be understood that the terminology used is intended to be in the nature of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, it is to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. | A dielectric ceramic composition of high dielectric constant and low dielectric loss, which can be co-fired with Ag electrodes, is provided for use in various parts of electric and electronic appliances. Based on a base composition with a high dielectric constant, the composition comprises glass frit and optionally CuO, as represented by the following formula:
a wt. % { x CaO- y 1 Sm 2 O 3 - y 2 Nd 2 O 3 - w Li 2 O- z TiO 2 }+b wt. % (ZnO—B 2 O 3 —SiO 2 based or Li 2 O—B 2 O 3 —SiO 2 based glass frit)+ c wt. % CuO
wherein, 13.0 mol %≦x≦20.0 mol %; 10.0 mol %≦y 1 +y 2 ≦17.0 mol %; 6.0 mol %≦w≦11.0 mol %; 60.0 mol %≦z≦67.0 mol % with the proviso that x+y 1 +y 2 +w+z=100; 85.0 wt. %≦a≦97.0 wt. %; 3.0 wt. %≦b≦15.0 wt. %; and c≦7.0 wt. %. | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a stacked structure used as a structure for, e.g., storing water in the underground.
2. Description of the Related Art
There is known a conventional structure for storing water in the underground as disclosed in, e.g., Japanese Unexamined Patent Publication No. 8-184080. The disclosed structure is constructed by excavating in the ground, forming a hollowed portion surrounded by a water-proof layer and a water-proof-layer protective material in the underground, installing a number of perforated pipes within the hollowed portion to fit with one another in close contact relation, and supporting from below an upper floor concrete and a water-proof layer by the perforated pipes. The disclosed structure also includes a water supply pipe and a water discharge pipe both communicating with the hollowed portion and the aboveground.
The conventional structure for storing water in the underground, however, requires a great space in operation of transporting and keeping the perforated pipes, which are to be installed in the hollowed portion, to and in the work site. Also, arranging the perforated pipes so as to fit with one another is not easy and positioning the perforated pipes in place takes time. Another problem is that manufacture of the perforated pipes pushes up a cost due to a complicated configuration thereof.
SUMMARY OF THE INVENTION
The present invention has been made in view of the problems stated above, and its object is to provide a stacked structure which is lightweight and strong in strength, the structure being not limited in applications to storing of water in the underground.
To achieve the above object, according to a first aspect of the present invention, there is provided a stacked structure comprising skeleton members each having mountain-shaped portions or skeleton part with substantially mountain-like shapes successively repeated in one section and substantially the same sectional form extending in a direction perpendicular to the section, the skeleton members being stacked together to form the stacked structure, wherein when stacking the skeleton members together, bottom ends of the mountain-shaped portions with substantially mountain-like shapes successively repeated in one of two adjacent skeleton members are arranged to cross top ends of the mountain-shaped portions of the other skeleton member.
According to a second aspect, there is provided a stacked structure comprising skeleton members each having mountain-shaped portions with substantially mountain-like shapes successively repeated in an X-axis direction and substantially the same sectional form extending in a Y-axis direction orthogonal to the X-axis direction, the skeleton members being stacked together in a Z-axis direction orthogonal to the X-axis direction and the Y-axis direction to form the stacked structure, wherein when stacking the skeleton members together, bottom ends of the mountain-shaped portions with substantially mountain-like shapes successively repeated in one of two skeleton members adjacent each other in the Z-axis direction are arranged to cross top ends of the mountain-shaped portions of the other skeleton member.
According to a third aspect, there is provided a stacked structure comprising skeleton members each having mountain-shaped portions with substantially mountain-like shapes successively repeated in section cut along a Z-axis orthogonal to the X-axis, and substantially the same sectional form extending along a Y-axis orthogonal to both the X-axis and the Z-axis, the skeleton members being stacked together along the Z-axis to form the stacked structure, wherein when stacking the skeleton members together, bottom ends of the mountain-shaped portions with substantially mountain-like shapes successively repeated in one of two skeleton members adjacent each other along the Z-axis are arranged to cross top ends of the mountain-shaped portions of the other skeleton member.
According to a fourth aspect, in the stacked structure according to the first, second or third aspect, the rear side of the mountain-shaped portions is shaped in conformity with the configuration of the mountain-shaped portions on the front side, and individual rear-side spaces are defined on the rear side of the mountain-shaped portions.
According to a fifth aspect, in the stacked structure according to the first, second or third aspect, the rear side of the mountain-shaped portions is shaped in conformity with the configuration of the mountain-shaped portions on the front side, individual rear-side spaces are defined on the rear side of the mountain-shaped portions, and reinforcing members are provided in the individual rear-side spaces to interconnect opposed slopes of the mountain-shaped portions on the rear side for reinforcing the mountain-shaped portions.
According to a sixth aspect, in the stacked structure according to the second or third aspect, bottom recesses provided at the bottom ends of the mountain-shaped portions in one of two adjacent skeleton members stacked in the Z-axis direction are engaged with top recesses provided at the top ends of the mountain-shaped portions of the other skeleton member, the bottom recesses are portions recessed when looking at the bottom ends from the rear side of the skeleton member, and the top recesses are portions recessed when looking at the top ends from the front side of the skeleton member.
According to a seventh aspect, in the stacked structure according to the second or third aspect, bottom recesses provided at the bottom ends of the mountain-shaped portions in one of two adjacent skeleton members stacked in the Z-axis direction are engaged with top recesses provided at the top ends of the mountain-shaped portions of the other skeleton member; the top recesses are portions recessed when looking at the top ends from the front side of the skeleton member, and provide hollow spaces each surrounded by first and second top slopes inclined in respective directions to cross the top end of the mountain-shaped portion, and a third top flat surface connected at both ends to the first and second top slopes and extended parallel to the top end of the mountain-shaped portion; the bottom recesses are portions recessed when looking at the bottom ends from the rear side of the skeleton member, and provide hollow spaces each surrounded by first and second bottom slopes inclined in respective directions to cross the bottom end of the mountain-shaped portion, and a third bottom flat surface connected at both ends to the first and second bottom slopes and. extended parallel to the bottom end of the mountain-shaped portion; each of the top end of the mountain-shaped portion and. the bottom end of the mountain-shaped portion has an included angle θ; the first and second top slopes intersect at an angle θ such that the first and second top slopes are inclined to separate away from each other outward and approach closer inward; the first and second bottom slopes intersect at an angle θ such that the first and second bottom slopes are inclined to separate away from each other outward and approach closer inward; and in a state where the bottom recess is engaged with the top recess, the third top flat surface and the third bottom flat surface lie in opposed relation to each other, the first and second bottom slopes lie in opposed relation to the front side of the mountain-shaped portion of one adjacent skeleton member, and the first and second top slopes lie in opposed relation to the rear side of the mountain-shaped portion of another adjacent skeleton member.
According to an eighth aspect, in the stacked structure according to the first, second or third aspect, the rear side of the mountain-shaped portions is shaped in conformity with the configuration of the mountain-shaped portions on the front side, individual rear-side spaces are defined on the rear side of the mountain-shaped portions, and openings are provided to penetrate the mountain-shaped portions from the front side to the rear side, whereby water is allowed to pass through the openings and a space including the individual rear-side spaces defined between the skeleton members stacked one above another is utilized to store water in the underground.
According to a ninth aspect, in the stacked structure according to the first, second or third aspect, the rear side of the mountain-shaped portions of the lowermost skeleton member is shaped in conformity with the configuration of the mountain-shaped portions on the front side, and individual rear-side spaces are defined on the rear side of the mountain-shaped portions, and lowermost reinforcing members which are flat at lower surfaces are provided in contact relation to the opposed slopes of the mountain-shaped portions on the rear side, thereby filling the individual rear-side spaces of the lowermost skeleton member.
According to a tenth aspect, in the stacked structure according to the first, second or third aspect, a front-side space is defined between two adjacent mountain-shaped portions of the uppermost skeleton member, and a flat surface member having an upper flat surface is provided in contact relation to opposed slopes of the adjacent mountain-shaped portions on the front side so as to fill the front-side space, the upper surface of the flat surface member lying flush with the top ends of the mountain-shaped portions.
Further, according to an eleventh aspect of the present invention, there is provided a stacked structure comprising skeleton members each having mountain-shaped portions with substantially mountain-like shapes successively repeated in an X-axis direction, top recesses and bottom recessed provided respectively in top ends and bottom ends of the mountain-shaped portions, and substantially the same sectional form extending in a Y-axis direction orthogonal to the X-axis direction, the skeleton members being juxtaposed in a plane extending in the X-axis direction and the Y-axis direction orthogonal to the X-axis direction, the skeleton members being stacked and juxtaposed on the juxtaposed skeleton members in a Z-axis direction orthogonal to the X-axis direction and the Y-axis direction, thereby forming stages of the stacked structure successively in the Z-axis direction, wherein the mountain-shaped portions of the skeleton members each stacked in the Z-axis direction on two adjacent skeleton members in the above plane are arranged in crossed and straddling relation to the mountain-shaped portions of the two adjacent skeleton members in the above plane; the bottom recesses of the skeleton member stacked in the Z-axis direction on the two adjacent skeleton members in the above plane are engaged with the top recesses of the two adjacent skeleton members in the above plane; the top recesses are portions recessed when looking at the top ends from the front side of the skeleton member; and the bottom recesses are portions recessed when looking at the bottom ends from the rear side of the skeleton member.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic sectional view of an underground water-storing structure using a stacked structure according to one embodiment of the present invention.
FIG. 2 is a schematic perspective view of a skeleton member used in FIG. 1 .
FIG. 3A is a schematic front view of the skeleton member of FIG. 2 and FIG. 3B is a schematic plan view of the skeleton member of FIG. 2 .
FIG. 4 is a schematic view showing a state where the skeleton members each shown in FIG. 2 are stacked in crossed relation.
FIGS. 5A to 5 G are schematic sectional views showing various examples of mountain-shaped portions of the skeleton member of FIG. 2 .
FIG. 6 is a schematic view showing a state where the skeleton members each shown in FIG. 2 are stacked one above another in the same direction.
FIG. 7 is a schematic view of a skeleton member which is formed in foldable fashion, the skeleton member being in a folded state.
FIG. 8 is a schematic perspective view of the stacked structure according to one embodiment of the present invention.
FIG. 9 is a schematic perspective view of a modification of the skeleton member shown in FIG. 8 .
FIG. 10A is a schematic partly-enlarged plan view showing part of FIG. 3 in enlarged scale and FIG. 10B is a schematic sectional view taken along line 10 B— 10 B in FIG. 10 A.
FIG. 11A is a schematic partly-enlarged plan view showing a modification of the skeleton member :shown in FIG. 10 A and FIG. 11B is a schematic sectional view taken along line 11 B— 11 B in FIG. 11 A.
FIG. 12 is a schematic perspective view showing a modification of the skeleton member shown in FIG. 9 .
FIG. 13 is a schematic sectional view showing a modification of the underground water-storing structure shown in FIG. 1 .
FIG. 14A is a schematic plan view of a state where the skeleton members each shown in FIG. 2 are arranged in juxtaposed relation to form a first stage, FIG. 14B is a schematic plan view of a state where the skeleton members each shown in FIG. 2 are arranged in juxtaposed relation to form a second stage on the first stage, and FIG. 14C is a schematic plan view of a state where the skeleton members each shown in FIG. 2 are arranged in juxtaposed relation to form a third stage on the second stage.
FIG. 15 is a schematic plan view of a state where in a process of stacking the second stage on the first stage, one of the skeleton members of the second stage is laid in crossed and straddling relation to the mountain-shaped portions of two skeleton members juxtaposed in the first stage.
FIG. 16 is a schematic perspective view showing the stacked structure in the case where lowermost reinforcing members and flat surface members are disposed respectively under and over the stacked structure.
FIG. 17 is a schematic perspective view showing another modification of the skeleton member shown in FIG. 2 .
FIG. 18 is a schematic view showing a state where the skeleton members each shown in FIG. 17 are stacked one above another in the same direction.
FIG. 19 is a schematic view of a state where the skeleton members each shown in FIG. 17 are arranged in juxtaposed relation.
FIG. 20 is a schematic sectional view of a state where the stacked structure according to one embodiment of the present invention is heaped up on the ground.
FIG. 21 is a schematic sectional view of a waterway in which the stacked structure according to one embodiment of the present invention is installed.
FIG. 22 is an enlarged view of part of FIG. 4 .
FIG. 23 is a schematic sectional view taken along line 23 — 23 in FIG. 22 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of the present invention will be described below with reference to the drawings. As one embodiment of a stacked structure according to the present invention, a sectional view of FIG. 1 shows an underground water-storing structure wherein the stacked structure is used to provide a structure for storing water in the underground. A space 10 is formed by excavating in the ground, and side walls 11 of the space 10 have sloped surfaces. The side walls 11 and a floor surface 12 of the space 10 are is subjected to a conventional water-shielding treatment, thereby defining a water-shielding space. Thus permeation of water between the interior and exterior of the space is cut off.
Incidentally, the term “water-shielding treatment” used herein means that a water-shielding sheet S is disposed to cover peripheries of a stacked structure 40 , which is formed by, e.g., stacking skeleton members 50 (or plate-like members) shown in FIGS. 2, 3 A and 3 B in such a state as shown in FIGS. 1 and 4, i.e., bottom, side and top surfaces of the stacked structure 40 , thereby defining a water-shielded space within the surrounding sheet S, the space being utilized to store water in the underground.
Further, as shown in FIG. 1, a receiving reservoir 21 for collecting rainwater, etc. is provided in the ground surface. A water conduit 20 (water introducing portion) for introducing rainwater, etc. from the receiving reservoir 21 to an upper portion of the water-shielded space is provided to, for example, penetrate the water-shielded space S. Accordingly, rainwater, etc. are supplied from the receiving reservoir 21 to the water-shielded space through the water conduit 20 .
In the water-shielded space, the skeleton members 50 are stacked one above another. Each of the skeleton members 50 has top cut-out recesses 55 and bottom cut-out recesses 57 , described later, formed therein to function as openings allowing water to pass through them. With water allowed to pass through the openings (top recesses 55 and bottom recesses 57 ), the space including individual rear-side spaces 52 a formed between the stacked skeleton members 50 , as described later, is utilized as an underground water-storing tank.
In addition, a discharge unit 30 is provided to discharge rainwater, etc. from the interior of the water-shielded space to the exterior of the water-shielded space, e.g., a tank (not shown) on the ground surface. The discharge unit 30 comprises, for example, a discharge pipe 31 provided to penetrate the water-shielding sheet S, a pump 32 and a water delivery pipe 33 . The discharge pipe 31 is arranged in a lower portion of the water-shielded space to interconnect the interior and exterior of the water-shielded space. Rainwater, etc. in the water-shielded space are sent by the pump 32 from the discharge pipe 31 to the water delivery pipe 33 .
Provided within the water-shielded space is the stacked structure 40 which comprises the skeleton members 50 (or plate-like members) stacked in crossed, e.g., orthogonal, relation and has a vacant space therein.
As shown in FIGS. 2, 3 A and 3 B, the skeleton members 50 are substantially rectangular in plan view and have such a form as obtained by folding a flat plate, which is substantially uniform in thickness, parallel to a long side (extending in a Y-axis direction Y) alternately while advancing along a short side (i.e., in an X-axis direction X), the form including mountain-shaped portions 51 with mountain-like shapes successively repeated in the X-axis direction. A perspective view of the skeleton member 50 is shown in FIG. 2 .
In other words, each skeleton member 50 (or plate-like member) has;
the mountain-shaped portions or skeleton parts 51 with substantially mountain-like shapes successively repeated in one section and substantially the same sectional form extending in a direction perpendicular to the above section,
specifically, the mountain-shaped portions 51 with substantially mountain-like shapes successively repeated in the X-axis direction X and substantially the same sectional form extending in the Y-axis direction Y orthogonal to the above X-axis direction X, and
more specifically, the mountain-shaped portions 51 with substantially mountain-like shapes successively repeated in section cut along both an X-axis and a Z-axis orthogonal to the X-axis, and substantially the same sectional form extending along a Y-axis orthogonal to both the X-axis and the Z-axis.
Further, the skeleton member 50 (or plate-like member) has the top recesses 55 and the bottom recesses 57 through which the skeleton members 50 to be stacked are engaged with each other. The top recesses 55 and the bottom recesses 57 are formed to function not only as means for holding the skeleton members 50 in place, but also as openings penetrating the mountain-shaped portions 51 from the front side to the rear side so that water is allowed to pass through the top recesses 55 and the bottom recesses 57 . Incidentally, the bottom recesses 57 imply cut-out portions recessed when looking at a bottom end 56 from the rear side of the skeleton member 50 , and the top recesses 55 imply cut-out portions recessed when looking at a top end 54 from the front side of the skeleton member 50 .
The skeleton member 50 is substantially uniform in thickness, and the mountain-like shape on the front side is substantially the same as the mountain-like shape on the rear side. Stated otherwise, the rear side of the mountain-shaped portions 51 is shaped in conformity with the form of the mountain-shaped portions 51 on the front side and the individual rear-side spaces 52 a are defined on the rear side of the mountain-shaped portions 51 , as shown in FIGS. 2 and 3B. Accordingly, when the skeleton members 50 are stacked successively in the same orientation, they are placed together in closely contact relation. On the other hand, when the skeleton members 50 are stacked successively to extend in orthogonal directions as shown in FIG. 4, there is defined a space between one skeleton member 50 and another skeleton member 50 (the space including the individual rear-side spaces 52 a defined on the rear side of the mountain-shaped portions 51 and individual front-side spaces 52 b defined on the front side of the mountain-shaped portions 51 , as shown in FIGS. 3 B and 4 ). By transporting and keeping the skeleton members 50 while stacking them in the same orientation as shown in FIG. 6, therefore, a required space can be reduced. Also, the stacked structure 40 shown in FIG. 4 can be constructed as a structure having spaces therein and a relatively small density.
Although the stacked structure 40 can be held as an integral structure by using, e.g., fasteners (not shown) or the like after stacking the skeleton members 50 one above another, it can also be kept integral by merely fitting the top recesses 55 and the bottom recesses 57 (in the form of, e.g., cut-out portions) with each other.
When forming the stacked structure 40 by stacking the skeleton members 50 together in the Z-axis direction orthogonal to both the X-axis direction and the Y-axis direction, the skeleton members 50 are arranged to extend in orthogonal relation, but not limited to the orthogonal arrangement. The skeleton members 50 may be stacked (in the Z-axis direction Z) such that the upper and lower mountain-shaped portions at least cross each other.
In other words, as shown in FIG. 4, two skeleton members 50 adjacent to each other in the Z-axis direction Z are stacked in such an arrangement that the bottom ends 56 of the successive mountain-shaped portions 51 of one skeleton member 50 (shown at, by way of example, character A) cross (more desirably perpendicularly intersect) the top ends 54 of the successive mountain-shaped portions 51 of the other skeleton member 50 (shown at, by way of example, character B).
Here, the entire density (weight) of the stacked structure 40 can be appropriately designed depending on applications, and materials of the skeleton members 50 constituting the stacked structure 40 can be properly selected from, e.g., synthetic resins and metals.
The skeleton members 50 can also be manufactured by molding a resin with a mold. The molding process can contribute to reducing a cost and a further reduction in weight. The skeleton member 50 may be integrally molded to be incapable of extending and contracting (or pivoting) such that it does not open at folds (the top ends 54 and the bottom ends 56 ), or may be formed such that it can extend and contract (or pivot through a hinge structure) in the X-axis direction X at the folds (the top ends 54 and the bottom ends 56 ).
In the latter case, the skeleton member 50 is spread into an extended state when used, but can be folded into a contracted state as shown in FIG. 7 when transported to and kept in the work site. This enables the skeleton member 50 to be easily handled in transporting and keeping it, and also contributes to reducing a required space. There is no problem in holding the skeleton member 50 in a state having the predetermined mountain-like shape. In case the folds cannot hold the skeleton member 50 in the predetermined mountain-like shape and the skeleton member 50 is fully extended into a flat state, the stacked structure 40 can be obtained as a stable structure by providing means for restricting the skeleton member 50 from being extended and contracted in the X-axis direction X when stacked, e.g., later-described cutouts through which the skeleton members 50 are fitted with each other.
The scope of “the mountain-shaped portions 51 with substantially mountain-like shapes” which constitute the skeleton member 50 in the present invention is not limited to a mountain-like shape successively repeated in one direction as shown in FIG. 5A, but may include a shape having a flat top in the mountain-like shape as shown in FIG. 5B, a shape with vertical walls as shown in FIG. 5C, and a wavy shape as shown in FIG. 5 D. In addition, it may also include a shape having a flat portion between the mountain-like shapes adjacent to each other, as well as a flat portion in each mountain-shaped portion, these flat portions being equidistantly or inequidistantly spaced, as shown in FIGS. 5E, 5 F and 5 G. The type and size of the mountain-shaped portions can be determined case by case in consideration of various conditions in use.
In this embodiment, the outer configuration of each skeleton member 50 is rectangular in plan view as shown in FIGS. 2, 3 A and 3 B, but it may be suitably shaped corresponding to the form of the water-shielded space intended without being limited to the rectangular shape.
Also, while the skeleton member 50 is substantially uniform in thickness, the thickness may be partly changed to some extent, or the stack height may be changed in the direction in which the skeleton members 50 are stacked one above another.
It is thus only required for the outer configuration of the skeleton member 50 that the rear surfaces of the mountain-shaped portions 51 having successive mountain-like shapes on the front side are formed in conformity with the configuration of front surfaces of the mountain-shaped portions 51 having the successive mountain-like shapes, and the individual rear-side spaces 52 a are defined on the rear side of the mountain-shaped portions 51 .
Engagement between the skeleton members 50 stacked together to construct the stacked structure 40 will be described below. As shown in FIGS. 2, 3 A and 3 B, the top recesses 55 and the bottom recesses 57 are provided in plural number respectively at the top ends 54 and the bottom ends 56 of the mountain-shaped portions 51 along the folds (the top ends 54 and the bottom ends 56 ) with predetermined intervals therebetween. Because the top recesses 55 and the bottom recesses 57 are in the form of cutouts, a reduction in space required for transporting and keeping the skeleton members is not impaired.
As shown in FIG. 4, a predetermined interval a between the top recesses 55 , and between the bottom recesses 57 is set smaller than an open end interval b between the adjacent top ends 54 an 54 (or adjacent bottom ends 56 and 56 ) in the mountain-shaped portions 51 each having a first leg portion 58 and a second leg portion 59 coupled to each other at the top end 54 .
Of two adjacent skeleton members 50 stacked in the Z-axis direction Z, therefore, the bottom recesses 57 formed at the bottom ends 56 of the mountain-shaped portions 51 of one skeleton member 50 (shown at, by way of example, character A in FIG. 4) are respectively engaged with the top recesses 55 formed at the top ends 54 of the mountain-shaped portions 51 of the other skeleton member 50 (shown at, by way of example, character B in FIG. 4 ).
Particularly, as shown in FIG. 4, the top recesses 55 are each defined as a hollow space surrounded by first and second top slopes 55 K, 55 L inclined in respective directions to cross the top end 54 of the mountain-shaped portion 51 , and a third top flat surface 55 M connected at both ends to the first and second top slopes 55 K, 55 L and extended parallel to the top end 54 of the mountain-shaped portion 51 . The bottom recesses 57 are each defined as a hollow space surrounded by first and second bottom slopes 57 K, 57 L inclined in respective directions to cross the bottom end 56 of the mountain-shaped portion 51 , and a third bottom flat surface 57 M connected at both ends to the first and second bottom slopes 57 K, 57 L and extended parallel to the bottom end 56 of the mountain-shaped portion 51 .
Further, the top end 54 and the bottom end 56 of the mountain-shaped portion 51 have each an included angle θ. The first and second top slopes 55 K, 55 L also intersect at an angle θ such that they are inclined to separate away from each other outward and approach closer inward. Likewise, the first and second bottom slopes 57 K, 57 L intersect at an angle θ such that they are inclined to separate away from each other outward and approach closer inward.
Accordingly, in a state where the bottom recess 57 is engaged with the top recess 55 , the third top flat surface 55 M and the third bottom flat surface 57 M lie in opposed (more desirably contact) relation to each other, the first and second bottom slopes 57 K, 57 L of one skeleton member 50 (shown at, by way of example, character A in FIG. 4) lie in opposed (more desirably contact) relation to the front side of the mountain-shaped portion 51 of the other skeleton member 50 (shown at, by way of example, character B in FIG. 4 ), and the first and second top slopes 55 K, 55 L of one skeleton member 50 lie in opposed (more desirably contact) relation to the rear side of the mountain-shaped portion 51 of another adjacent skeleton member 50 . Then, the bottom recess 57 and the top recess 55 are tightly engaged (more desirably fitted) to each other such that the tightly engaged skeleton members 50 are prevented from moving in the X-axis and Y-axis directions while being allowed to move only in the Z-axis direction Z (when loosely fitted, the skeleton members 50 are movable in the X-axis and Y-axis directions as well).
The bottom recesses 57 each have a substantially hexagonal shape in plan view as shown in FIGS. 2 and 3A. Note that the top recesses 55 and the bottom recesses 57 can also serve as openings allowing water to pass therethrough because they are formed to penetrate the skeleton member 50 from the front side to the rear side.
The intervals between the adjacent top recesses 55 and between the adjacent bottom recesses 57 along the folds (the top ends 54 and the bottom ends 56 ) are selected, as explained above, such that the top recesses 55 and the bottom recesses 57 are engaged with each other when the skeleton members 50 are stacked in orthogonal directions.
The optimum intervals between the adjacent top recesses 55 and between the adjacent bottom recesses 57 can be therefore determined depending on the size and configuration of the mountain-shaped portions 51 of the skeleton members 50 .
The top recesses 55 and the bottom recesses 57 are provided in positions shifted a half pitch from one another in the Y-axis direction Y. With that relative positional relationship, it is possible to stack the structure in the upright direction (Z-axis direction Z) by using one type of skeleton members 50 , reduce types of skeleton members 50 to be used, and hence lower a cost. Additionally, the stacked structure 40 can be formed into various shapes by changing the relative positional relationship as required.
In the case of folding the flat skeleton member 50 to form the mountain-shaped portions 51 as stated above, the top recesses 55 and the bottom recesses 57 can be provided in similar fashion.
FIG. 4 shows a state where the skeleton members 50 are stacked and engaged with each other between adjacent two. Engagement between the top recesses 55 and the bottom recesses 57 enables the skeleton members 50 to be stacked together in orthogonal direction with no need of positioning, makes easier the work of stacking the skeleton members 50 , and increases the working efficiency.
Further, by tightly fitting the top recesses 55 and the bottom recesses 57 with each other in the stacked state, the skeleton members 50 are restricted from moving in the X-axis and Y-axis directions. With a load applied to the stacked structure from above, therefore, the skeleton members 50 are kept from disengaging from the fitted state and the need of fixing the skeleton members 50 in place by fasteners or the like is eliminated. This results in even easier stacking work, the reduced number of parts, an improvement of the working efficiency, a reduction in cost, and so on.
For the skeleton member 50 capable of extending and contracting along the folds (the top ends 54 and the bottom ends 56 ) as stated above, extension and contraction of the skeleton member 50 are restricted by the top recesses 55 and the bottom recesses 57 fitting with each other. Incidentally, hinge-like extension and contraction of the skeleton member 50 (movement of the leg portions thereof) in the lowermost stage can be restricted by using, e.g., an auxiliary member 61 (lower flat plate) shown in FIG. 8 .
When neither cutouts nor recesses are provided in the skeleton members 50 , the stacked structure rises in the Z-axis direction Z in increment corresponding to the height of the individual rear-side spaces 52 a on the rear side of the mountain-shaped portions 51 for each stage when the skeleton members 50 are stacked together such that the X-axis direction X of the skeleton member 50 crosses alternately. With the provision of cutouts or the like, the skeleton members 50 are engaged with each other when stacked and the height of the stacked structure per stage is reduced correspondingly. However, the above-stated advantages of eliminating the need of positioning, making easier the stacking work, etc. can be achieved.
In this embodiment, the skeleton members 50 are all provided with cutouts in the same pattern and stacked together while meshing with each other at the cutouts so that the skeleton members 50 are restricted from moving in the X-axis and Y-axis directions. However, the cutouts may be provided, for example, such that the skeleton members 50 are allowed to move only in any one direction. By so providing the cutouts, the stacked structure 40 can be easily stacked to have an inclined surface and hence can be adapted for the water-shielded space having an inclined surface.
After laying the individual skeleton members 50 over a plane extending in the X-axis direction X and the Y-axis direction Y while stacking them in the Z-axis direction Z until the stacked structure 40 is stacked up to a position near the ground surface, a ceiling portion 13 capable of shielding penetration of water therethrough is placed to cover the water-shielded space and level with the ground surface, as shown in FIG. 1 . Since the skeleton members 50 are stacked together with the cutouts fitted to each other, water passages can be secured by the presence of the top recesses 55 and the bottom recesses 57 . Further, the flat working surface can be achieved by providing a top plate 62 (upper flat plate), shown in FIG. 8, over the skeleton members 50 in the uppermost stage and a bottom plate 61 (lower flat plate), shown in FIG. 8, under the skeleton members 50 in the lowermost stage.
In the above-explained embodiment, the top recesses 55 and the bottom recesses 57 of the mountain-shaped portions 51 are formed as openings which penetrate the skeleton member 50 from the front side to the rear side and have functions to not only hold the skeleton members 50 through mutual engagement but also allow water to pass therethrough. However, if the top recesses 55 and the bottom recesses 57 are made open entirely, the strength of the skeleton members 50 may not be held at a satisfactory level in some cases.
In such a case, each skeleton member 50 may have top recesses 55 and bottom recesses 57 which are dented, but have no through holes, for example, as shown in FIG. 9 . This case requires that openings K penetrating the mountain-shaped portions 51 from the front side to the rear side are separately provided as holes allowing water to pass therethrough in appropriate positions such as the top ends, bottom ends or slopes of the mountain-shaped portions 51 . For example in FIG. 9, the openings K are provided at the top ends.
More specifically, the top recesses 55 and the bottom recesses 57 may be entirely closed as shown in FIG. 9 . As an alternative, as shown in FIGS. 10A and 10B, the top recesses 55 and the bottom recesses 57 may be partly closed by reinforcing members H which are provided in the individual rear-side spaces 52 a to interconnect the slopes on the rear side of the mountain-shaped portions 51 while reinforcing the mountain-shaped portions 51 (with the openings K left in the top recesses 55 and the bottom recesses 57 ). Further, as shown in FIGS. 11A and 11B, reinforcing members H may be provided in the individual rear-side spaces 52 a to interconnect the slopes on the rear side of the mountain-shaped portions 51 awhile the top recesses 55 and the bottom recesses 57 are entirely closed, thereby enhancing the strength of the mountain-shaped portions 51 .
Furthermore, a stacked structure 40 shown in FIG. 13 can be formed by using skeleton members 50 , 50 ′ shown in FIGS. 9 and 12, respectively. Each of the skeleton members 50 , 50 ′ has the mountain-shaped portions 51 with substantially mountain-like shapes successively repeated in the X-axis direction X, the top recesses 55 provided in the top ends 54 of the mountain-shaped portions 51 , and substantially the same sectional form extending in the Y-axis direction Y orthogonal to the X-axis direction X. For example, the mountain-shaped portions 51 of the skeleton members 50 are provided in four lines (see FIG. 9) and the mountain-shaped portions 51 of the skeleton members 50 ′ are provided in two lines (see FIG. 12 ).
Then, as shown in FIG. 14A, the skeleton members 50 are arranged in juxtaposed relation over a plane extending in the X-axis direction X and the Y-axis direction Y orthogonal to the X-axis direction to form a first stage (lowermost layer). Over the juxtaposed skeleton members 50 , as shown in FIGS. 14B and 14C, the skeleton members 50 , 50 ′ are juxtaposed and stacked in the Z-axis is direction Z orthogonal to both the X-axis direction X and the Y-axis direction Y. Second, third and further stages of the skeleton members 50 are thus stacked successively in the Z-axis direction Z, thereby forming the stacked structure 40 in the form of a rectangular parallelepiped shown in FIG. 13 .
In the above process, one skeleton member (shown at, by way of example, character E in FIGS. 14 and 15) is placed in the Z-axis direction Z on two adjacent skeleton members (shown at, by way of example, characters C, D in FIGS. 14 and 15) in a plane extending in the X-axis direction X and the Y-axis direction Y orthogonal to the X-axis direction such that the mountain-shaped portions of the former skeleton member lie in crossed and straddling relation to the mountain-shaped portions of the latter two skeleton members. Further, bottom recesses (the bottom recesses 57 in FIG. 9) provided in the bottom ends 56 of the mountain-shaped portions 51 of one skeleton member (shown at, by way of example, character E in FIGS. 14 and 15 ), which is placed in the Z-axis direction Z on two adjacent skeleton members (shown at, by way of example, characters C, D in FIGS. 14 and 15) in the above plane, are engaged with top recesses (the top recesses 55 in FIG. 9) provided in the top ends 54 of the two adjacent skeleton members in the above plane. The two adjacent skeleton members (shown at, by way of example, characters C, D in FIGS. 14 and 15) in the above plane are thereby coupled to each other.
The above-explained embodiment has a disadvantage that a load imposed on the stacked structure 40 is concentratedly applied to the lowermost skeleton member 50 . To solve such a disadvantage, lowermost reinforcing members 41 , each being flat at a lower surface and substantially triangular, are provided in contact relation to the opposed slopes of the mountain-shaped portions on the rear side, respectively, so as to fill the individual rear-side spaces 52 a defined on the rear side of the mountain-shaped portions of the lowermost skeleton member 50 . Thus, the lowermost reinforcing members 41 bear the load imposed on the stacked structure 40 , thereby reducing the load applied to the lowermost skeleton members 50 and improving the strength of the stacked structure 40 .
Also, the top plate 62 is provided in the above-explained embodiment. Instead of the top plate 62 , however, a flat surface member 42 having an upper flat surface may be provided in contact relation to the opposed slopes of two adjacent mountain-shaped portions (shown at characters F, G in FIG. 16) on the front side so as to fill each front-side space 52 b defined between two adjacent mountain-shaped portions 51 of the uppermost skeleton member 50 on the front side. The upper surfaces of the flat surface members 42 lie flush with the top ends 54 of the mountain-shaped portions.
Further, the above embodiment has been explained as being applied to the water-shielded space. The stacked structure of the present invention can also be employed in a space where rainwater, etc. are temporarily stored and then allowed to gradually permeate into the ground. Such a space may be formed by excavating in the ground, or surrounding a certain area by soil and sand or the like to define an enclosed space.
While in the above-explained embodiment the skeleton member 50 has the mountain-shaped portions with substantially mountain-like shapes successively repeated in the X-axis direction X, a skeleton member 50 (plate-like member) modified as described below has the mountain-shaped portion 51 with a single mountain-like shape in the X-axis direction X. In this modification, the skeleton member 50 has an appearance as shown in FIG. 17 . Thus, the skeleton member 50 of this modification is obtained by dividing the skeleton member 50 shown in FIG. 2 from each other in units of the mountain-shaped portion.
When stacking the skeleton members 50 together to form the stacked structure 40 , therefore, the skeleton members 50 are first arranged side by side to form an assembly with mountain-like shapes successively repeated in the X-axis direction X. Then, the skeleton members 50 are stacked to form successive stages in orthogonal relation. The stacked structure 40 is thus widely adapted for a desired outer configuration size.
When the skeleton members 50 as shown in FIG. 12 are placed in the same orientation one above another, they can also be stacked in closely contact relation as shown in FIG. 18 . Further, in an intermediate portion of the stacked structure, the skeleton members 50 may be arranged at every other top recess or several top recesses apart. The stacked structure 40 can be thus formed in many variations in consideration of various conditions including installation places.
In addition to the assembly comprising the skeleton members 50 arranged side by side continuously without spacings, an assembly may be formed by (though not shown) arranging the skeleton members 50 at every other top recess, for example. By using the skeleton members 50 each having one mountain-shaped portion 51 , the stacked structure can be appropriately adapted for installation places. Also, by arranging those skeleton members 50 in alternately inverted orientations to form an assembly 72 as shown in FIG. 19, the stacked structure 40 can have a higher degree of strength as a whole and can be adapted for a variety of environments in use.
In the above embodiment, the present invention has been explained as the underground water-storing structure using the stacked structure 40 ; namely in the stacked structure 40 , water is allowed to pass through the openings in the skeleton members 50 and a space including the individual rear-side spaces 52 a defined between the skeleton members 50 stacked together is utilized to store water in the underground. However, the present invention is not limited to the above embodiment. For example, as shown in FIG. 20, a level of the ground surface 81 can be raised by using the stacked structure 40 in which the skeleton members 50 are stacked together in crossed relation, and covering only outer surfaces of the stacked structure 40 with earth and sand or the like 82 .
Generally, heavy materials such as soil and sand or concrete are used to raise the ground level, but work of reinforcing the foundation is required in places where the foundation is not firm, resulting in a longer term of scheduled work and an increased cost. By using the stacked structure 40 having a space therein, it is possible to omit the work of reinforcing the foundation even in places where the foundation is soft, shorten the term of scheduled work, and cut down a cost. In such a case, to prevent soil and sand or the like from entering the interior of the stacked structure 40 , the stacked structure 40 is first surrounded by a sheet 83 and soil and sand or the like 82 is then covered over the sheet 83 . Since a load acts on the stacked structure 40 from above due to the surrounding soil and sand, the skeleton members 50 can be maintained in the fitted condition explained above under the load, and therefore the stacked structure 40 can be firmly kept as an integral structure.
In addition, the stacked structure 40 in which the skeleton members 50 are stacked together in crossed relation can also be applied to other structures serving as, for example, gathering blocks for fish, wave canceling blocks, waterways, water gates, and walls. When applied to gathering blocks for fish, the stacked structure 40 can be handled as one integral structure by stacking and coupling the skeleton members 50 and the top plate 62 (upper flat plate), as shown in FIG. 8 . If a relatively heavy plate is used as the top plate 62 , the skeleton members 50 are kept from disengaging from the fitted condition at the cutouts thereof because of the weight of the stacked structure 40 itself and hence fasteners are not required. If the skeleton members 50 are manufactured by, e.g., a synthetic resin other than metals, there is no fear of rusting even with the stacked structure 40 immersed in sea water. Further, since metal-made fasteners are not required, the stacked structure 40 having high durability can be provided without a fear of corrosion such as rusting. A larger number of water introducing holes may be provided, if necessary, to reduce resistance against water flow.
When applied to waterways, the ecology of fish, etc. can be maintained by providing the stacked structure 40 at each of opposite lower ends of a concrete-made waterway. This results in such advantages as making work easier, reducing the term of scheduled work and the cost, and facilitating maintenance. In that case, materials of the plate-like members, the configuration and size of the mountain-shaped portions of each plate-like member, the positions, number and size of the openings, etc. may be determined as required.
With the stacked structure according to the first (second or third) aspect, the skeleton members are relatively light since a space is left between adjacent mountain-shaped portions of each of the skeleton members. Further, when stacking the skeleton members together, bottom ends of the mountain-shaped portions with substantially mountain-like shapes successively repeated in one of two adjacent skeleton members are arranged to cross top ends of the mountain-shaped portions of the other skeleton member. Therefore, the stacked structure having a high degree of strength can be achieved.
With the stacked structure according to the fourth aspect, since the rear side of the mountain-shaped portions is shaped in conformity with the configuration of the mountain-shaped portions on the front side, the skeleton members can be formed to be thinner and lighter in addition to the above-stated advantages obtainable with the first aspect.
With the stacked structure according to the fifth aspect, since reinforcing members are provided to interconnect opposed slopes of the mountain-shaped portions on the rear side for reinforcing the mountain-shaped portions, the stacked structure having a higher degree of strength can be achieved in addition to the above-stated advantages obtainable with the first aspect.
With the stacked structure according to the sixth aspect, the stacked structure can be assembled just by engaging bottom recesses provided at the bottom ends of the mountain-shaped portions in one of two adjacent skeleton members stacked in the Z-axis direction with top recesses provided at the top ends of the mountain-shaped portions of the other skeleton member. In addition to the above-stated advantages obtainable with the first aspect, therefore, the stacked structure can be assembled easily, can firmly hold a stacked state of the skeleton members stacked in the Z-axis direction, and has a higher degree of strength.
With the stacked structure according to the seventh aspect, the stacked structure having a higher degree of strength than obtainable with the fourth aspect can be achieved.
With the stacked structure according to the eighth aspect, the following advantage can be obtained in addition to the above-stated advantages obtainable with the first aspect. When the stacked structure is covered along its peripheries by a shield sheet, for example, to be used as a structure for storing water, water received by the upper skeleton member is introduced to the lower skeleton member through openings provided in the mountain-shaped portions, and individual spaces defined between the adjacent mountain-shaped portions of the skeleton member can be utilized to store water.
With the stacked structure according to the ninth aspect, since lowermost reinforcing members are provided to bear a load imposed on the stacked structure, the load imposed on the mountain-shaped portions of the lowermost skeleton member can be reduced and the stacked structure having a higher degree of strength can be achieved in addition to the above-stated advantages obtainable with the first aspect.
With the stacked structure according to the tenth aspect, a flat surface member having an upper flat surface is provided to be contacted at slopes thereof with opposed slopes of the adjacent mountain-shaped portions on the front side while the upper surface of the flat surface member is lying flush with the top ends of the mountain-shaped portions, thereby providing an upper flat surface of the stacked structure. In addition to the above-stated advantages obtainable with the first aspect, therefore, it is possible to fill front-side recessed spaces which are formed at a top of the stacked structure when it is constructed by stacking the skeleton members one above another.
Further, with stacked structure according to the eleventh aspect, the mountain-shaped portions of the skeleton members each stacked in the Z-axis direction on two adjacent skeleton members in a plane are arranged in crossed and straddling relation to the mountain-shaped portions of the two adjacent skeleton members in the above plane. In addition to the above-stated advantages obtainable with the first aspect, therefore, the skeleton members can be stacked in the Z-axis direction while coupling the two adjacent skeleton members in the above plane to each other, and the stacked structure having a higher degree of strength can be achieved. | A stacked structure especially useful for storing water in the underground is formed of a plurality of skeleton members. Each skeleton member includes a plurality of skeleton parts extending in one direction and situated side by side in a lateral direction perpendicular to the one direction. Each skeleton part has one top portion, and two bottom portions extending from the top portion, wherein one bottom portion in one skeleton part is connected to one bottom portion in the adjacent skeleton part. Also, each skeleton part includes top recesses formed at the top portion to be spaced apart from each other at a predetermined interval, and bottom recesses formed at the bottom portions to be spaced apart from each other at a predetermined interval. The skeleton members form upper and lower skeleton members to be vertically stacked together. The skeleton parts of the upper and lower skeleton members extend perpendicularly to each other. The bottom recesses of the upper skeleton member are located in the top recesses of the lower skeleton member so that the upper and lower skeleton members are securely assembled together. | 4 |
BACKGROUND OF THE INVENTION
This invention relates generally to meltblowing apparatus and processes for producing electrically charged meltblown fabrics.
Meltblown nonwoven fabrics display excellent properties for many uses, one of which is liquid and gas filtration. Important filtration parameters such as efficiency and fluid pressure drop can be improved by embedding a static electrical charge within the fabric. In addition, electrically charged nonwoven fabrics may display improved tactile hand. The present invention applies a persistent electrical charge to nonwoven meltblown fabrics.
Meltblown fabrics are generally formed by extruding a molten thermoplastic resin through a die which consists of a horizontal row of small diameter orifices. High velocity sheets of hot air exiting from air passages located just above and below the orifices converge at the die discharge. The convergent air streams induce an aerodynamic drag force upon the extruded polymer fibers as they exit the die. The drag rapidly draws or attenuates the polymer into extremely fine fibers forming a fiber-air stream. The degree of fiber attenuation or, in other words, the final fiber diameter has a significant effect on the final properties of the fabric. The fiber-air stream is directly blown onto a collector apparatus. Here the fibers are deposited forming a nonwoven fabric or web. Nonwoven webs are held together by a combination of fiber entanglement and/or fiber cohesive sticking while still in the semi-molten state. By using a suitable collector apparatus the entire process can be more or less continuous. The term "fiber" includes filaments since the extruded polymer can be deposited as discrete fibers or continuous filaments.
The microscopic diameters(average diameter of 0.5 to 10 microns generally) of the extruded fibers of the meltblown web are well suited to filtering finely divided particles out of a gaseous or liquid fluid. Experimental studies have shown that applying a persistent electrostatic charge to the fibers improves the filter quality. Webs carrying an electrical charge are often called electrets. Nonwoven fibrous electret filters have higher efficiencies, lower fluid pressure drop during filtration, and longer life than non-charged filters. U.S. Patents which disclose nonwoven fibrous electrets include U.S. Pat. Nos. 4,215,682, 4,375,718, 4,588,537, 4,592,815, and 4,904,174.
A method for applying an electrostatic charge to the molten or hot fibers during the fabrication process is disclosed in U.S. Pat. No. 4,215,682. The electrostatic charging of the molten or hot fibers permits the charges to migrate into the fibers(since its electrical resistance is lower) and remain trapped upon cooling. This increases the charge life of the electret.
In the processes disclosed in U.S. Pat. Nos. 4,215,682 and 4,904,174, the charges are applied by establishing within a region near the die discharge a corona zone of free electrons and ionized air. The extruded polymer fibers and air stream pass through the dense electron and ionized air field and are charged thereby. The external charging of the fibers limits the proximity of the electron and ionized air field. Because of the spacing required in these devices, the extruded polymer fibers are generally in a semi-molten or solidified state when they pass through the electron or ionized air field.
SUMMARY OF THE INVENTION
In accordance with the present invention, a meltblowing apparatus and method operate by charging the air used to draw down and attenuate the fibers. The meltblowing apparatus may be a conventional die equipped with internal charging elements mounted in the die on opposite sides of the meltblowing die orifices through which the fibers are extruded. With this system, the hot air is ionized within the air flow passages prior to coming into contact with the extruded resin and the formation of the fiber-air stream. In addition to ionized air molecules a number of electrons may also be convected into the fiber-air stream. Upon contacting and mixing with the extruded thermoplastic fibers, the ionized air molecules and electrons attempt to neutralize themselves by transmitting charges to the fibers. The charges are able to penetrate and migrate into the molten or semi-molten thermoplastic resin where they become trapped as the resin cools and solidifies.
In the present invention, the electrostatic charge is applied to the molten or semi-molten thermoplastic fibers almost instantly as they exit the die tip. In the charging system disclosed in U.S Pat. No. 4,588,537, the electrostatic charge is applied after the fibers have been collected and the web has been formed. It is advantageous to apply the charge to the thermoplastic while still in the molten or semi-molten state because its electrical resistance is lower than in the solid phase and the resin will accept charges more readily.
It is also significant that the present invention avoids the problem of bringing the charged particles into contact with the semi-molten fibers as in the case of the charging system disclosed in U.S. Pat. No. 4,215,682. In that system, ambient air is ionized between a high voltage electrode wire and a grounded shell which partially surrounds the wire. This device is located external to the die and does not act directly upon the convergent air streams used for attenuating and blowing the extruded fibers. The ionized ambient air thus formed is subsequently propelled into the fiber-air stream.
In the present invention, the convergent hot air streams for attenuating and blowing the extruded fibers are ionized by placing a high voltage electrode in the hot air flow passages. The electrode may be a metal rod or wire extending across the air passage with the axis of the electrode oriented generally perpendicular to the the air flow direction. If the air passages are formed inside the die body, the electrode is mounted so that it is electrically insulated from the die, and the die body itself is electrically grounded.
When the electrode is connected to a high d.c. voltage source, a strong electrostatic field is established between the electrode and the die body. Molecules of air which have been naturally ionized(by molecular collisions, cosmic rays and other natural phenomenon) will be induced to move within the electrostatic field. In the case of a positively charged electrode, electrons and negatively charged air ions will be attracted toward the electrode. If the strength of the electrostatic field is high enough, the ions (especially the electrons), as they are drawn toward the electrode, will receive such large accelerations that, by collision with air molecules, they will produce many more ions by a cascade process. A negatively charged electrode will produce a similar effect, but in the opposite direction. In either case, the air is thus made much more conducting, and the discharge of electrons at the electrode by corona discharge may be very rapid. A large number of ions and charges are thus convected into the fiber-air stream. Within the fiber-air stream, the thermoplastic fibers become charged in the manner discussed above and may be collected to form a nonwoven fibrous electret in a more or less continuous process.
The process of the present invention is characterized by the steps of (a) extruding molten thermoplastic resin through a plurality of orifices to form a plurality of molten fibers, (b) ionizing and charging convergent high velocity hot air streams (c) blowing said convergent sheets of hot, ionized air on both sides of the fibers to (i) attenuate the fibers, (ii) imbed a persistent electrostatic charge within the fibers, and(iii) form a fiber-air stream, (d) collecting the charged fibers to form a fibrous electrically charged web.
Experimental tests have shown that charging the molten or hot fibers in accordance with the present invention produces a filter of exceptional filtration efficiency. Although the present invention has been described in relation to filter applications, it should be pointed out that electrically charged webs may have other applications. The filtration efficiency test is an effective measure of the charge on the webs, even if the webs are used for other applications.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic illustrating the main components of a meltblown line provided with the electrostatic apparatus of the present invention.
FIG. 2 is a fragmentary, cross sectional view of the die shown in FIG. 1 illustrating the die components and the location of the electrodes in the hot air flow ducts.
FIG. 3 is an enlarged sectional view illustrating the means for mounting the electrode in the die with the cutting plane taken generally along line 3--3 of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As stated previously, the present invention relates to the electrostatic charging of meltblown molten or hot fibers to produce electrically charged nonwoven webs. A meltblown line is illustrated in FIG. 1 as comprising an extruder 10 for delivering molten resin to a meltblowing die 11 which extrudes fibers into converging hot air streams which flow from air passages forming a fiber-air stream 12. The fiber-air stream impinges on a rotating collector drum or screen 14 for separating the fibers and air and forming a web 15. Web 15 is withdrawn from the screen 14 and collected as a roll for storage or transportation. The web is held together by fiber entanglement and fiber cohesive sticking while still in the molten or semi-molten state. The typical meltblowing line will also include a compressed air source connected to the die 11 through valved lines 17 and heating elements(not shown).
As shown in FIG. 2, the die 11 includes body members 20 and 21, an elongate nosepiece 22 secured to the die body by bolts 26, and air knives 23 and 24. The nosepiece has a converging section 29 of triangular cross section terminating at tip 30. A central elongate passage 31 is formed in the nosepiece 22 and a plurality of side-by-side orifices 32 are drilled in the tip 30. The die components are generally manufactured from high quality steel to provide durability. Molten polymer is delivered from the extruder through the die passages of coat hanger configuration(not shown), through passage 31, and extruded as micro-diameter side-by-side fibers from the orifices 32.
The air knives 23 and 24 with the body members 20 and 21 define air passages 36 and 37. The air knives 23 and 24 have tapered inwardly facing surfaces which in combination with the tapered surfaces of the nosepiece define converging air passages 38 and 39. End panels 18 and 19 provide end closures for air passages 36, 37, 38, and 39. The flow area of each air passage 38 and 39 is adjustable. Heated air is delivered from a source via lines 17 through the air passages and is discharged onto opposite sides of the extruded molten fibers as convergent sheets of hot air. The converging sheets of hot air draw or attenuate the fibers forming a fiber and air stream 12 discharging from die discharge 41. The die may be of the same general construction as that described in U.S. Pat. No. 4,904,174, the disclosure of which is incorporated herein. For retrofitting the electrodes in the die, it may be necessary to enlarge a portion of the air passages 36, 37 for receiving the electrodes. As mentioned above, the air passages should provide sufficient clearance to avoid arcing.
In accordance with the present invention, the meltblowing apparatus shown in FIGS. 1 and 2 is provided with means for applying electrostatic charges to the fibers as they discharge from the die discharge opening 41. The electrostatic charges are applied by electrically charging and ionizing the convergent hot air streams which flow through air flow passages 36 and 37. The electrically charged air streams converge at die discharge 41 and mix with the extruded fibers exiting from die orifices 32. The charged air molecules attempt to neutralize themselves by exchanging charges with the extruded fibers. The charged fibers may be collected on rotating collector drum 14 of FIG. 1 and an electrically charged nonwoven fibrous web 15 is withdrawn.
In accordance with the present invention, the meltblowing apparatus of FIG. 2 is equipped with high voltage electrodes 44 and 45 for electrically charging and ionizing the hot air streams flowing through air passages 36 and 37. The electrodes may be a small diameter metal(electrical conductor) rod or wire oriented transversely the air flow direction. In addition, the electrode wires may span the breadth (direction perpendicular to the plane of FIG. 2) of the air flow passages 36 and 37.
In operation, the electrodes 44 and 45 are electrically insulated from the die body components, and the die body components are electrically grounded. A high voltage source is connected to the electrodes 44 and 45 (top/bottom) and the polarity controlled so that the electrodes may have a +/+ charge, +/- charge, or a -/- charge configuration. This establishes the electrostatic field and corona zone for charging and ionizing the air flows. As previously discussed, the ionized air molecules will pass charges to the extruded fibers upon mixing in the fiber-air stream. As indicated above, the equipment for installation onto the meltblowing line comprises the electrode wires and a high voltage source. These are discussed in some detail below.
Electrode Wires: The electrode wires 44 and 45 should be electrical conductors and constructed of a material which resists corrosion and oxidation, such as steel.
The diameter of the electrode wires is not critical, however, the wires should be strong enough so they can be mounted in tension to avoid the possibility of the wire electrically shorting-out against the walls of the air flow passages 36 and 37. This possibility arises when considering the aerodynamic loads on the electrode wires due to the air flow. This may give rise to flow induced motions such as flow induced vibrations or simply deflection of the electrode wires due to aerodynamic drag. On the other hand, the wire diameter should obviously be small enough so as not to significantly obstruct the air streams. Electrode diameters of 0.002 to 0.03 inches are preferred and those of 0.005 to 0.02 inches most preferred. The smaller the diameter, the lower the voltage needed to ionize the air.
The electrode wires are located inside the air flow passages 36 and 37 and spaced a sufficient distance from the walls to prevent arcing. This will depend on the voltage and the spacing of the electrode to the air passage walls. A general guideline is to provide 0.1 inch spacing per 3500 volts. Thus, for most dies with a voltage of 5 kV, spacings of 0.15 inches would be adequate.
As previously noted, the electrodes are electrically insulated from the die body. Assemblies 42 and 43 may be used to secure opposite ends of the electrode wires to the die body, as illustrated in FIG. 3. Assembly 42 is mounted in hole 19A of panel 19 and assembly 43 in hole 18A of panel 18, with electrode wire 44 stretched therebetween, spanning substantially the length of air passage 36, and generally perpendicular to the air flow therethrough.
Assembly 43 comprises bushing 46 mounted in panel hole 18A, jack member 47 abutting bushing 46, and jack cap 48 threaded to member 47. Bushing 46 is made of an insulating or dielectric material such as ceramic and has a hole 49 sized to sealingly receive wire 44. One end of the electrode wire 44 is attached to the exposed end of jack cap 48 by brazing or a connector as at 51. Connection 51 supports one end of a tensile load in wire 44 induced by assemblies 42 and 43 as described below. The tension is transmitted through the threaded connection between jack cap 48 and retainer 47 and compresses the retainer against bushing 46. Wire 44 extends through the mounting assembly 43, through panel hole 18A, and into air passage 36.
Assembly 42 retains the opposite end of wire 44 and compresses a bushing 52 comprised of a ceramic or dielectric material, spring 53, and retainer 54. Bushing 52 fits into hole 19A in close conformity and supports one end of compression spring 53 on embossment 55. The opposite end of spring 53 seats on retainer 54. Bushing 52 has a large central opening 57, closed at one end which has a small hole 58 formed therein. Wire 44 fits closely in hole 58 to provide a fluid seal therebetween but still permit a small amount of longitudinal movement.
Wire 44 extends through the assembly 42 and is anchored on retainer 54 by a wire clip or other connector 59. The spring 53 urges one end of the wire outwardly from panel 19 maintaining wire 44 disposed in passage 36 in tension and allowing for thermal expansion and contraction. Thus, wire 44 is insulated from the die body by insulated members 46 and 52. Jack cap 48 may be turned relative to member 47 to adjust the compression of spring 53 and, in turn, the tension in wire 44. It should be noted that the spring 53 retains the assemblies 42 and 43 against their respective side of the die 11, so that threaded parts are not essential. Similar assemblies 42 and 43 are provided to retain wire 45 in air passage 37.
As shown in FIGS. 1 and 3, the wire 44 is connected to d.c. power source 60 and the die body is grounded. The wire 45 is also connected to the d.c. power source as indicated in FIG. 1.
Any high voltage d.c. source may be used. The current drawn in the charging process is small(viz. less than 10 mA). The source should have variable voltage settings (e.g. 1 kV to 10 kV) and preferably (-) and (+) polarity settings to permit adjustments in establishing the electrostatic field.
Operation: In operation, the electrostatic charge equipment will be mounted on a meltblowing line. The line may employ any of the thermoplastic resins capable of use in meltblowing. The preferred polymer is polypropylene, but other polymers may be used such as low and high density polyethylene, ethylene, copolymers (including EVA copolymer), nylon, polyamide, polyesters, polystyrene, poly-4-methylpentene, polymethylmethacrylate, polytrifluorochloroethylene, polyurethanes, polycarbonates, silicones, and blends of these.
The meltblowing line produces fibers less than 10 microns in diameter, typically 1 to 5 microns.
The line is started and once steady state operation is achieved, the electrostatic charge system may be activated. This establishes an electrostatic field between the electrode 44 and the grounded die walls of air passage 36 and between electrode 45 and the die walls of air passage 37. The air passing through the electric field is charged as described previously and contacts the molten polymer fibers as they are discharged from the orifices.
A rotating collector drum or screen, which may include an electrical insulating film over and around the collector surface, is located in the meltblown fiber-air stream. The rate of rotation is adjusted in relation to the fiber-air stream flow rate and the desired web thickness.
As the newly formed web is carried away from the fiber-air stream by the rotating collector drum, it may be withdrawn from the collector by some mechanical means.
EXPERIMENTS
Experiments were carried out on the production of electrostatically charged webs produced with the charging apparatus of the present invention. Web properties including filtration efficiency and sample weight were measured. The test equipment and materials included the following:
Meltblowing Die: 20 inch width with twenty 0.015 diameter orifices per inch; extrusion temperature: 450°-550° F.; polymer flow rate: 0.2 to 0.8 grams per minute per orifice.
Electrodes: Two steel wires 0.010 inches in diameter were installed to span each air passage of a 20 inch long die.
Resin: polypropylene (PP 3145 marketed by Exxon Chemical Co.)
Charging Device: variable(0 to ±25 kV) d.c. voltage source. The test voltages and polarities are indicated in Table 1.
Filtration Efficiency Measurements: The effect of electrostatic charge was determined by filtration tests using the following apparatus.
Apparatus: Refined surgicos FET apparatus (described in "Automated Test Apparatus for Rapid Simulation for Bacterial Filtration Efficiency"; L.C. Wadsworth; 13th Technical Symposium, International Nonwovens and Disposable Assoc.; Jun. 4-6, 1985; Boston)
Aerosol: 10% suspension of 0.8 or 0.5 micrometer latex spheres in a distilled water fog.
Counting: optical particle counter ##EQU1##
Test Results: The filtration efficiency data and basis weight data for charged webs produced using the present invention are shown in Table 1. The corresponding data for a noncharged, but otherwise similar web produced on the same meltblowing line is also shown for comparison as Sample 1. From these data it is evident that the present invention significantly improves the filtration efficiency of nonwoven fibrous webs. It is significant that the filtration efficiencies of the charged webs produced with the present invention are very comparable to those reported for the charging system disclosed in U.S. Pat. No. 4,904,174. This was achieved at much lower voltage. It should also be observed that the internal charging is much safer than the external charging systems of the prior art.
Although the present invention has been exemplified in relation to electrically charged nonwoven webs used for filters, the invention may be used to produce electrically charged webs useful in a variety of other applications.
TABLE 1______________________________________Electrodes Filtration(top/bottom) Basis Efficiency Voltage Current Weight (0.6 μm) (0.8 μm)Sample (kV) (mA) (oz./yd.sup.2) (%) (%)______________________________________1 0/0 0/0 1.0 90.9 91.5(control)2 +3.7/+3.3 1.0/1.0 1.0 98.7 98.13 +3.5/+3.1 0.5/0.5 1.0 97.7 97.74 -2.6/-2.4 1.0/1.0 1.0 96.2 96.2______________________________________
Although the preferred embodiment of the present invention contemplates the installation of the electrodes in the air chamber of this die, variations include placing the electrode in the polymer flow path internal of the die to impact a charge to the polymer prior to extrusion through the orifices.
The electrodes in the air chambers may be of the same or different polarities. The electrodes in the polymer melt may be of the same polarity as the electrodes in the air chambers if used in combination, but preferably of opposite polarities. When opposite polarities are used, different power sources must be connected to each electrode. | Electrically charged meltblown webs are formed by convergingly discharging electrically charged hot air onto a row of extruded polymer fibers to contact the fibers thereby (i) attenuating and stretching the fibers and (ii) imparting an electric charge to the fibers. The fibers may be continuous or discontinuous. | 3 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to locks and latches and more particularly pertains to a new child resistant latch system for minimizing a child's access to cabinets containing potentially harmful items.
2. Description of the Prior Art
The use of locks and latches is known in the prior art. More specifically, locks and latches heretofore devised and utilized are known to consist basically of familiar, expected and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which have been developed for the fulfillment of countless objectives and requirements.
Known prior art includes U.S. Pat. No. 5,647,618; U.S. Pat. No. 4,715,628; U.S. Pat. No. 3,999,792; U.S. Pat. No. 2,233,699; U.S. Pat. No. 3,397,001; and U.S. Pat. No. Des. 338,150.
While these devices fulfill their respective, particular objectives and requirements, the aforementioned patents do not disclose a new child resistant latch system. The inventive device includes a spring loaded biasing assembly for biasing a handle that is operationally coupled to a latch positioned proximate a stop plate.
In these respects, the child resistant latch system according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of minimizing a child's access to cabinets containing potentially harmful items.
SUMMARY OF THE INVENTION
In view of the foregoing disadvantages inherent in the known types of locks and latches now present in the prior art, the present invention provides a new child resistant latch system construction wherein the same can be utilized for minimizing a child's access to cabinets containing potentially harmful items.
The general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new child resistant latch system apparatus and method which has many of the advantages of the locks and latches mentioned heretofore and many novel features that result in a new child resistant latch system which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art locks and latches, either alone or in any combination thereof.
To attain this, the present invention generally comprises a spring loaded biasing assembly for biasing a handle that is operationally coupled to a latch positioned proximate a stop plate.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There arc additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
It is therefore an object of the present invention to provide a new child resistant latch system apparatus and method which has many of the advantages of the locks and latches mentioned heretofore and many novel features that result in a new child resistant latch system which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art locks and latches, either alone or in any combination thereof.
It is another object of the present invention to provide a new child resistant latch system that may be easily and efficiently manufactured and marketed.
It is a further object of the present invention to provide a new child resistant latch system that is of a durable and reliable construction.
An even further object of the present invention is to provide a new child resistant latch system which is susceptible of a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such child resistant latch system economically available to the buying public.
Still yet another object of the present invention is to provide a new child resistant latch system which provides in the apparatuses and methods of the prior art some of the advantages thereof, while simultaneously overcoming some of the disadvantages normally associated therewith.
Still another object of the present invention is to provide a new child resistant latch system for minimizing a child's access to cabinets containing potentially harmful items.
Yet another object of the present invention is to provide a new child resistant latch system which includes a spring loaded biasing assembly for biasing a handle that is operationally coupled to a latch positioned proximate a stop plate.
Still yet another object of the present invention is to provide a new child resistant latch system that is usable with standard cabinet handles available without modification to the handle.
Even still another object of the present invention is to provide a new child resistant latch system that has substantially the same appearance of a standard conventional cabinet handle.
Even still another object of the present invention is to provide a child resistant latch system that requires special manipulation of a cabinet handle to release the latch from a stop plate in order to lock and unlock a cabinet.
These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:
FIG. 1 is a schematic perspective view of a new child resistant latch system according to the present invention.
FIG. 2 is a schematic cross-sectional view taken along line 2 — 2 of FIG. 5 .
FIG. 3 is a schematic perspective view of the latch receiving plate assembly of the present invention.
FIG. 4 is a schematic front view of the latch of the present invention.
FIG. 5 is a schematic perspective view of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference now to the drawings, and in particular to FIGS. 1 through 5 thereof, a new child resistant latch system embodying the principles and concepts of the present invention and generally designated by the reference numeral 10 will be described.
As best illustrated in FIGS. 1 through 5, the child resistant latch system 10 for minimizing a child's ability to open a door 2 generally comprises a latch member 20 , a handle 30 operationally coupled to the latch member, a stop plate 40 having a latch stop 42 , and a biasing assembly 50 for biasing the latch such that the latch stop engages the latch member to selectively prevent rotation of the latch member.
The stop plate 40 is designed for coupling to the door and includes a latch stop 42 that extends outwardly from an edge of the stop plate at substantially a right angle. The latch stop is positioned to engage a distal end of the latch member whereby the latch member is prevented from rotating.
The latch member is further designed to be manipulated into a locked position defined by the latch member extending outwardly from a perimeter edge 44 of the stop plate to engage a frame 4 of the door. Optionally, the latch may engage a latch receiving assembly 70 attached to the frame. Thus, the latch member is designed for preventing opening of the door when the door is closed and the latch member extends outwardly from the perimeter of the stop plate. The latch member can also be manipulated into an unlocked position defined by the latch member being positioned such that the door is free to move between an open and a closed position without the latch member engaging the frame of the door.
The biasing assembly includes a spring member 52 and a main member 60 .
The main member is generally cylindrical and is designed for insertion into and through a circular hole in the door. The main member is further structured to have a spring chamber 62 for receiving an end of the spring member therein.
The main member also includes a connecting portion 66 extending outwardly from a first end 64 of the main member. The connecting portion is for inserting through the stop plate and a connection hole 22 in the latch. The connection hole is preferably non-circular such that rotation of the connecting portion results in a rotational force on the latch.
In use, the spring member is partially compressed between the stop plate and the main member. The stop plate is fixed to the door such that the spring member biases the handle outwardly from the stop plate and the latch to abut against the stop plate.
The connecting portion includes a lip 68 for abutting against the latch so that the latch is urged outwardly into a spaced relationship from the stop plate when the handle is urged towards the stop plate. The space provided between the stop plate and the latch is sufficient that the latch may now be rotated to clear the latch stop, thus permitting the latch to be rotated between the locked position and the unlocked position.
The main member includes a duct 69 extending fully through the main member and through the connecting portion. A bolt 36 is inserted fully through the duct in the main member and is attached to the handle. The bolt includes a bearing surface 37 for abutting the latch to hold the latch in position relative to the main member. Optionally, a washer 38 may be used between the bearing surface and the latch.
Optionally, a latch receiving plate assembly 70 may be installed on a door frame not structured to naturally engage the latch when the latch is in the locking, position. The receiving plate 70 includes a latch abutment plate 79 , a frame connection plate 74 disposed from the latch abutment plate at substantially a right angle, and a support web 76 extending between edges of the abutment plate 72 and the connection plate 74 . Optionally, the web plate also functions to prevent excessive rotation of the latch into the locked position.
As to a further discussion of the manner of usage and operation of the present invention, the same should be apparent from the above description. Accordingly, no further discussion relating to the manner of usage and operation will be provided.
With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.
Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. | A child resistant latch system for minimizing a child's access to cabinets containing potentially harmful items includes a spring loaded biasing assembly for biasing a handle that is operationally coupled to a latch that is positioned proximate a stop plate. Optionally, a latch receiving plate assembly may be attached to a frame of the cabinet. | 4 |
FIELD OF INVENTION
Embodiments of the present invention provide a high pressure seal adapter that connects a splitter conductor housing to a wellhead of a well.
BACKGROUND
In the drilling industry, the term well completion is often used to denote the operations that prepare a well bore for producing oil or gas from the reservoir. It may similarly refer to a completed wellhead assembly. The goal of these operations is to install a wellhead and other connections to optimize the flow of the reservoir fluids into the well bore, up through the producing string, and into the surface collection system.
To begin a drilling operation a conductor pipe may be driven into the ground to prevent the loose surface soil from caving into the hole as the upper portion of the borehole is being drilled. Various components are then attached to the conductor pipe. A single conductor for 2 or more well completions is often used as it provides benefits such as smaller platform sizes and reduced installation time. Each well completion requires one wellhead to be installed before oil/gas production can commence. Thus 2 or more separate wellheads may be provided in a single conductor.
FIG. 1 shows a cross-sectional view of one example of a prior art conductor pipe assembly, designated generally as reference numeral 10 . FIG. 1A illustrates a close-up cross-sectional view of the circled portion “A” of FIG. 1 . FIG. 2 illustrates a cross-sectional view of the assembly 10 of FIG. 1 with two wellheads attached. FIG. 3 illustrates a top perspective view of the conductor housing of FIGS. 1 and 2 .
With continuing reference to FIGS. 1-3 , the assembly 10 includes a conductor 12 and a conductor housing 20 mounted to a top 14 of the conductor 12 . The conductor housing 20 includes two cylindrical holes 24 a , 24 b separated by a central section 26 that extends longitudinally into the central bore of the conductor 12 . The two cylindrical holes 24 a , 24 b of the assembly 10 facilitate the drilling of 2 separate wells 6 , 8 (represented graphically as the centerlines of the holes 24 a , 24 b ) within the conductor 12 . Typically, the following steps are required to complete the connection between the conductor housing 20 and each wellhead 30 a , 30 b ( FIG. 2 ). Usually, only one well ( 6 or 8 ) is worked on and the other well 6 , 8 is covered with a debris cap 16 .
For example as shown in FIG. 1 , during the installation phase, a riser 40 that is used to protect the well fluids from the environment is required to be installed before any drilling operations. In this example, the riser 40 is installed above well 6 . One or more seals 42 are located at the bottom of the riser 40 between an outside surface 44 of the riser 40 and an inside surface 22 of the conductor housing 20 . In this prior art assembly, the seals 42 directly contact the conductor housing 20 .
A separate debris cap 16 is installed on the conductor housing 20 to protect well 8 . As best shown in FIG. 1A , the debris cap 16 includes one or more seals 17 between the debris cap 16 and the inside surface 22 of the central portion 26 of hole 24 a in the conductor housing 20 . In this prior art wellhead, the riser 40 seals directly onto the conductor housing 20 . The “Sealing Thickness”, shown as T s , must be sufficient to hold pressure regardless of whether the riser 40 is installed in either of the cylindrical holes 24 a , 24 b above the well bores 6 , 8 . The thickness of the riser 40 is shown as T r . The total available thickness for well drilling operations is shown as T total . The portion marked T w is “Wasted Thickness” which is there to provide for the riser 40 to be installed when drilling operations are switched to the other bore. When no drilling operations go through that bore, the area is dead space and is considered wasted. This wasted thickness T w is undesirable.
After the well 6 is drilled through, a casing hanger 50 ( FIG. 2 ) is installed, and a casing 55 is inserted into the well 6 . The riser 40 is then dismantled. Subsequently, the wellhead 30 a is installed onto the conductor housing 20 . One or more seals 32 may be installed on an inside surface 34 of the wellhead 30 a to provide a leak-proof connection to an outside surface 52 of the casing hanger 50 .
In such a conductor splitter application, the wells 6 , 8 have to be located close to each other, constrained by the internal diameter of the conductor 12 , and the thickness T total of the central section 26 of the conductor housing 20 . Furthermore, the center to center distance 18 between well 6 and well 8 is constrained to allow two separate vertical bores to pass through the conductor housing 20 through cylindrical holes 24 b , 24 a , respectively. As the riser 40 and subsequently the wellhead 30 a , 30 b must be fitted within the boundary of each bore for well isolation, the wall thickness of the riser 40 is also constrained. The internal diameter of the riser 40 is also constrained by the minimum allowed diameter based on industry standards. Similarly, as the bottom of the riser 40 seals directly on the conductor housing 20 , the central section 26 must be sufficiently thick to withstand the well pressure and allow sealing on either side of the bore. These constraints limit the amount of pressure under which the wells 6 , 8 may operate. For example, in typical well completions as shown in FIGS. 1 and 2 , each well may be constrained to operate at a pressure of 3000 psi (20.6 MPascal) or less.
One solution to increase the available pressure in the wellhead is to use a smaller drill bit that would allow for a thicker riser wall. However, using a smaller drill bit also results in a smaller casing size for the well. While the operating pressure of the resulting well may be increased, the overall volume is less than what would be produced using the larger drill bit at the higher pressure. This is often unacceptable to the operator of the well. An alternate solution is to provide a larger conductor, thus increasing the center to center distance between the wells, so that the original drill bit may be used, and appropriate high-pressure wellheads installed. This option may greatly increase the cost of the required wellhead equipment.
Yet another solution is to use an underreamer which is able to pass through the riser and subsequently expand the cutter arms to enlarge the borehole. However, this solution increases both the time required and the costs associated with the drilling operation.
SUMMARY
One aspect of the present invention provides a high pressure seal adapter for a conductor housing of a wellhead, the high pressure seal adapter having a unitary body comprising: a first circular bore extending through said unitary body; and a second circular bore adjacent said first circular bore and extending through said unitary body; wherein said seal adapter is capable of being installed in said conductor housing.
In alternate embodiments, the high pressure seal adapter may further include at least one seal extending around a perimeter of said unitary body, said at least one seal contacting said conductor housing. The adapter may receive a high pressure riser in said first circular bore when said seal adapter is installed in said conductor housing, said high pressure riser having a lower surface that contacts said flange and at least one seal extending around an outside perimeter of said riser, said at least one seal contacting said side wall to facilitate well drilling operations through said high pressure riser and said first bore for a first well.
In further embodiments, the high pressure seal adapter may further include an upper and lower planar surface, wherein said lower planar surface rests on a flange of said conductor housing and said upper planar surface is substantially co-planar with an upper surface of said conductor housing when said seal adapter is installed in said conductor housing. The seal adapter may be rotated 180 degrees and installed in said conductor housing to facilitate well drilling operations for a second well. The high pressure seal adapter may be capable of operating at well pressures up to 34.5 Mega Pascals.
An alternate aspect of the present invention provides a method of facilitating high pressure drilling and extraction operations for a well, the well comprising a conductor having a conductor housing attached thereto, the method comprising the steps of: providing high pressure seal adapter having a unitary body comprising: a first circular bore extending through said unitary body; and a second circular bore adjacent said first circular bore and extending through said unitary body; and installing said seal adapter in said conductor housing.
In alternate embodiments, the method may further include connecting a high pressure riser to said conductor housing, said high pressure riser having a lower surface that extends into said first circular bore and contacts said flange, and at least one seal extending around an outside perimeter of said riser, said at least one seal contacting said side wall to facilitate well drilling operations through said high pressure riser and said first bore for a first well.
In other embodiments, when said well drilling operations are completed for said first well, the method may further include: removing said high pressure riser; removing said seal adapter; rotating said seal adapter 180 degrees; reinstalling said seal adapter in said conductor housing; connecting a first casing hanger through said second bore to the conductor housing; and connecting said high pressure riser to said conductor housing, said high pressure riser having a lower surface that extends into said first circular bore and contacts said flange, and at least one seal extending around an outside perimeter of said riser, said at least one seal contacting said side wall to facilitate well drilling operations through said high pressure riser and said first bore for a second well. When said well drilling operations are completed for said second well, the method may further include: removing said high pressure riser; connecting a second casing hanger through said first bore to the conductor housing; installing first and second casings in said first and second well, respectively; attaching a first wellhead to said conductor housing above said first well; and attaching a second wellhead to said conductor housing above said second well.
In alternate embodiments, the seal adapter may further include an upper and lower planar surface; and said step of installing said seal adapter may further include seating said lower planar surface on a flange of said conductor housing such that said upper planar surface is substantially co-planar with an upper surface of said conductor housing. The high pressure drilling and extraction operations may be conducted at well pressures up to 34.5 Mega Pascals.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will be better understood and readily apparent to one of ordinary skill in the art from the following written description, by way of example only, and in conjunction with the drawings, in which:
FIG. 1 illustrates a cross-sectional view of one example of a prior art conductor pipe assembly;
FIG. 1A illustrates a close-up cross-sectional view of the circled portion “A” of FIG. 1 ;
FIG. 2 illustrates a cross-sectional view of the assembly of FIG. 1 with two wellheads attached;
FIG. 3 illustrates a top perspective view of the conductor housing of the assembly of FIGS. 1 and 2 .
FIG. 4 illustrates a perspective view of one embodiment of a high pressure seal adapter according to the present invention;
FIG. 5 illustrates a top view of the high pressure seal adapter of FIG. 4 ;
FIG. 6 illustrates a cross-sectional side view of the high pressure seal adapter of FIGS. 4 and 5 ;
FIG. 7 illustrates a perspective view of one embodiment of a modified conductor housing that may be used with the seal adapter of FIGS. 4-6 ;
FIG. 7A illustrates a cross-sectional side view of the high pressure seal adapter of FIGS. 4-6 installed in the modified conductor housing of FIG. 7 ;
FIG. 8 illustrates a cross-sectional side view of a riser installed on the high pressure seal adapter of FIG. 7 ;
FIG. 9 is a top perspective view of the riser and seal adapter of FIG. 8 ;
FIG. 10 illustrates a cross-sectional side view of a riser installed on the high pressure seal adapter of FIG. 7 , which has been installed on the conductor housing in a reversed position;
FIG. 10A illustrates a close-up cross-sectional view of the circled portion “A” of FIG. 10 ; and
FIG. 11 illustrates a cross-sectional side view of two completed wellheads installed on the high pressure seal adapter of FIG. 7 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of the present invention provide a separate seal adapter that may be installed in a modified conductor housing. The seal adapter and modified conductor housing facilitate the drilling of well bores using standard sized drill bits, and allow for high pressure operation of the resulting wells. The example embodiment of the present invention will be discussed in an application using a standard 36 inch (0.9144 meter) conductor having two bore holes. However, it is understood that appropriately configured embodiments of the present invention may be used with conductors of any size and having two or more bore holes.
FIG. 4 illustrates a perspective view of one embodiment of a high pressure seal adapter 100 according to the present invention. FIG. 5 illustrates a top view of the high pressure seal adapter 100 of FIG. 4 . FIG. 6 illustrates a side view of the high pressure seal adapter 100 of FIGS. 4 and 5 .
The seal adapter 100 includes a first bore 110 and a second bore 120 that allow equipment access through the seal adapter 100 and conductor housing 150 ( FIG. 7 ) to the underlying conductor 12 . The first bore 110 and second bore 120 are separated by a central section 112 . As best shown in FIG. 5 , a circular perimeter 113 of the first bore 110 extends slightly beyond a centerline 107 of the seal adapter 100 . The seal adapter 100 may include one or more seals 102 a , 102 b located in corresponding grooves 104 a , 104 b respectively around an outside perimeter 106 of the seal adapter 100 . In the embodiment illustrated in FIGS. 4-6 , the first bore 110 may include a circular flange 108 extending partially into the bore 110 around an inside surface 109 . The flange 108 may have a downward taper that helps to prevent the accumulation of debris which may occur with a flat shoulder, and which also assists in guiding tools going into the bore 110 before the riser is installed. The bore 120 includes a substantially vertical inside surface 121 . This will be discussed in more detail below. The seal adapter 100 may have a planar upper surface 117 a , and a planar lower surface 117 b.
In this embodiment, the seal adapter 100 has a flattened oval “racetrack” profile as seen from the top ( FIG. 5 ) with substantially straight long edges 103 a , 103 b and substantially circular end portions 105 a 105 b . However, it is understood that other profiles may also be used without departing from the scope of the appended claims. For example, in some embodiments, a triangular shaped seal adapter 100 may be used in drilling operations that provide for three well bores in a single conductor. The seal adapter 100 may also include a plurality of mounting holes 111 drilled adjacent the long edges 103 a , 103 b that facilitate the connection of the seal adapter 100 to the risers 40 a , 40 b and/or the wellheads 30 a , 30 b . Alternately, the mounting holes 111 may facilitate the connection of the seal adapter 100 to the underlying conductor housing 150 . This will be discussed in more detail below.
FIG. 7 illustrates a perspective view of one embodiment of a modified conductor housing 150 that may be used with the seal adapter 100 of FIGS. 4-6 . FIG. 7 a illustrates a cross-sectional side view of the high pressure seal adapter 100 of FIGS. 4-6 installed in the modified conductor housing 150 of FIG. 7 . FIG. 8 illustrates a cross-sectional side view of the riser 40 a installed on the high pressure seal adapter 100 as mounted on the conductor housing 150 , as shown in FIG. 7 a . FIG. 9 is a top perspective view of the riser 40 a and seal adapter 100 of FIG. 8 . FIG. 10 illustrates a cross-sectional side view of the seal adapter 100 in a reversed position on the conductor housing 150 . This facilitates the installation of another riser 40 b that may be used to facilitate well completion for the well bore 6 . It is understood that riser 40 a may also be repositioned above well bore 6 for this purpose. FIG. 10A illustrates a close-up cross-sectional view of the circled portion “A” of FIG. 10 .
The installation and operation of the seal adapter 100 will now be described with reference to FIGS. 7-10 . As discussed above, once the conductor 12 has been driven into the ground at the desired drilling location, the conductor housing 150 is installed onto the top 14 of the conductor 12 . This process is known to those of skill in the art, and will not be described in detail here. It is understood that the conductor 12 may also be used in subsea operations. Embodiments of the present invention are thus not limited to surface wells, but may be used in any well drilling operation in which a conductor housing 150 is installed onto a conductor 12 .
With reference to FIG. 7 , once the conductor housing 150 has been installed onto the top 14 of the conductor 12 , the seal adapter 100 may be installed into the top of the conductor housing 150 . In this embodiment, a portion of central section 156 of the conductor housing 150 has been removed to provide a flange 157 to facilitate the connection between the seal adapter 100 and the conductor housing 150 . In this illustration, bore 110 of the seal adapter 100 is positioned above well bore 8 to facilitate well drilling operations ( FIG. 7 a ).
When installed in the conductor housing 150 , a portion of the lower surface 117 b of the seal adapter 100 rests on the corresponding flange 157 in the conductor housing 150 , while the upper surface 117 a of the seal adapter 100 is substantially flush with a top surface 155 of the conductor housing 150 . The seals 102 a , 102 b provide a pressure tight seal between the seal adapter 100 and an inside surface 152 of the conductor housing 150 . A bolt 132 may extend through corresponding holes in the risers 40 a , 40 b or wellheads 30 a , 30 b into each of the drill holes 111 of the seal adapter 100 . In alternate embodiments, the bolts 132 may extend through each of the drill holes 111 into corresponding holes in the conductor housing 150 to secure the seal adapter 100 to the conductor housing 150 .
As shown in FIGS. 8 and 9 , the riser 40 a may then be installed in bore 110 of the seal adapter 100 above wellbore 8 . As is known in the art, the riser 40 a may be thinner on one side to allow dismantling of the trash cap 16 a ( FIG. 8 ) while the riser 40 a is in place. A lower surface 41 of the riser 40 a may contact the flange 108 in the bore 110 of the seal adapter 100 . The riser 40 a may then be attached to the conductor housing 150 using a plurality of bolts 46 ( FIG. 9 ). A trash cap 16 a may also be installed into bore 120 of the seal adapter 100 . The trash cap 16 a may include one or more seals 17 a , 17 b between the inside surface 121 of the bore 120 and an outside surface 18 a of the trash cap 16 a . The trash cap 16 a may also include one or more seals 17 b , 17 b between the inside surface 152 of the conductor housing 150 and the outside surface 18 a of the trash cap 16 a.
After the riser 40 a is installed, various tools are run inside the riser 40 a to test the connection, drill for the next casing depth, wash the bore and to perform other well operations. Once drilling operations are completed, the riser 40 a and trash cap 16 a are removed from the conductor housing 150 .
With reference to FIG. 10 , the seal adapter 100 may then be removed, rotated 180 degrees such that the bore 110 is positioned above well bore 6 , and reinstalled into the conductor housing 150 as previously described. A casing hanger 50 a may then be installed through bore 120 of seal adapter 100 , and connected to the conductor housing 150 . A trash cap 16 b may then be installed in the bore 120 of the seal adapter 100 , and onto the casing hanger 16 b to protect the casing hanger 16 b from debris. The riser 40 b may then be installed in bore 110 of the seal adapter 100 above wellbore 6 . Drilling and other well operations are then commenced as previously described.
FIG. 10 a illustrates a close-up cross-sectional view of the circled portion “A” of FIG. 10 . As best shown in FIG. 10 a , one or more seals 42 are located at the bottom of the riser 40 a between an outside surface 44 of the riser 40 b and the inside surface 109 of the seal adapter 100 . Similarly, the trash cap 16 b may also include one or more seals 17 a between the inside surface 121 of the bore 120 and the outside surface 18 b of the trash cap 16 b , as well as one or more seals 17 b between the inside surface 152 of the conductor housing 150 and the outside surface 18 b of the trash cap 16 b.
By employing the seal adapter 100 in the modified conductor housing 150 , the thickness T r of the riser 40 b can be increased, while the total available thickness T total is approximately the same. This allows for increased pressures in the riser 40 b using the same conductors of the prior art.
FIG. 11 illustrates a cross-sectional side view of two wellheads 30 a , 30 b installed on the conductor housing 150 containing the high pressure seal adapter 100 of FIG. 7 . In this completed well, both of the casing hangers 50 and wellheads 30 a , 30 b have been installed onto the conductor housing 150 . The seal adapter 100 is left in the conductor housing 150 . As shown in the illustration, the seal adapter 100 does not interfere with the installation of the wellhead(s) 30 a , 30 b . The final position and orientation of the seal adapter 100 does not affect well operations. Subsequent operations from the installation of the wellhead 30 a , 30 b onwards are per normal well drilling and installation procedures, as know to those of skill in the art.
As best shown in FIGS. 8 , 10 and 10 a , the seal adapter 100 addresses the problems discussed above by shifting the seal position of the risers 40 a , 40 b from the conductor housing 20 of the prior art to the seal adapter 100 . Since the first bore 110 of the seal adapter 100 is slightly larger than what was available in the prior art, a riser 40 a having thicker walls may be used without reducing the size of the drill bit, or increasing the size of the conductor. The seal adapter 100 can be removed from the conductor housing 150 , rotated 180 degrees, and reinstalled in the conductor housing to facilitate riser installation through bore 110 of the seal adapter 100 to either of the 2 well bores 6 , 8 . This allows the risers 40 a , 40 b to be thicker than the conventional design, and still maintain the same inner diameter for equipment to pass through it. The thicker riser design allows for a higher overall pressure rating for each of the wells. By way of example and not limitation, a well that has been prepared as described above, and configured as shown in FIGS. 7-11 , may safely operate at pressures of up to 5000 psi (34.5 MPa). It is understood that even higher pressures may be obtained by using non-standard materials for the seal adapter.
It will be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects to be illustrative and not restrictive. | A high pressure seal adapter for a conductor housing of a wellhead, and a method of completing a well having a conductor housing attached thereto, are disclosed. The high pressure seal adapter has a unitary body including a first circular bore extending through the unitary body. The first circular bore has a circular perimeter extending beyond a centerline of the unitary body. The unitary body further includes a second circular bore adjacent the first circular bore and extending through the unitary body. The seal adapter is configured to be installed in the conductor housing. The method includes providing such a high pressure seal adapter and installing the high pressure seal adapter in the conductor housing. | 4 |
This application is a continuation in part of my application filed Jan. 5, 2005, Ser. No. 11/028,638 now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a paintball gun, and more particularly to one that applies pressurized air to directly fire a paintball, having the pressurized air passing through a spool, and to one that has a port blocked by turning a low pressure regulator to avoid hurting people by accidentally pulling a trigger.
2. Description of the Prior Art
Survival game in jungle is one of the popular sports around the world. In the game, a paintball gun is a primary weapon to be used for its safety consideration. To mitigate the risk of using paintball gun, a flask filled with pressurized air is essentially used as the power to shoot the paintball gun. As illustrated in FIG. 6 of the accompanying drawings, a barrel (A 1 ) of a paintball gun (A) is formed with a paintball drop hole (A 2 ) for a paintball (B) to drop therefrom into the barrel (A 1 ) to be ready to shoot. Upon the trigger (A 3 ) is pulled, a hammer (A 4 ) brings a spool (A 5 ) to strike the paintball (B) to fire.
However, when shooting the paintball (B), the speed starts from zero to fast speed instantly, which may cause deviation of the paintball (B).
Furthermore, the barrel (A 1 ) has a trough (A 6 ) at the endmost for a linking rod (A 7 ) provided between the hammer (A 4 ) and the spool (A 5 ) to slide along. The moving speed of the linking rod (A 7 ) is relative fast, which may pinch the user's finger or cause the user to trigger the paintball, accidentally.
SUMMARY OF THE INVENTION
It is the primary object of the present invention to provide a paintball gun, which utilizes high pressurized air to fire a paintball. The present invention comprises a spool disposed in a barrel. The barrel comprises a sleeve having an opening at a front end thereof. A spring is provided between the piston and the sleeve. A piston is provided in the sleeve to block the opening. Each of both the sleeve and the piston comprises a through hole penetrating outside. A through channel is disposed a rear section of the spool. A low-pressure regulator is provided in an air storage chamber. The low pressure regulator is provided with a block. When the trigger is pulled, low pressure air enters the through channel to push the piston and to advance the paintball, while pressurized air passes from the air storage chamber in sequence through a port and the through holes of the sleeve and the piston to fire the paintball. By having the pressurized air to directly fire the paintball, there would be no fast move by the spool protruding out of the barrel, thus there is no chance that the hand of the user to get hurt. When the low-pressure regulator is turned to block the port, it stops the pressurized air in the air storage chamber from entering into the barrel, thus to prevent accidentally pulling the trigger to hurt somebody.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a preferred embodiment of the present invention;
FIG. 2 is a cross-sectional view showing that a paintball is loaded into the preferred embodiment of the present invention;
FIG. 3 is a cross-sectional view showing that low pressure air pushes a piston to advance the paintball of the preferred embodiment of the present invention;
FIG. 4 is a cross-sectional view showing that high pressure air fires the paintball of the preferred embodiment of the present invention;
FIG. 5 is a cross-sectional view showing that a low pressure regulator is turned to block a port of an air storage chamber of the preferred embodiment of the present invention; and
FIG. 6 is a cross-sectional view of a striking structure of the prior art.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in FIGS. 1 and 2 , a preferred embodiment of the present invention comprises a frame ( 1 ), a spool ( 2 ) and a low pressure regulator ( 3 ).
The frame ( 1 ) comprises a barrel ( 11 ) therein. A paintball drop hole ( 12 ) is disposed on the barrel ( 11 ), and an air storage chamber ( 13 ) is provided underneath the barrel ( 11 ). A port ( 14 ) is disposed at a front section between the air storage chamber ( 13 ) and the barrel ( 11 ), and a key hole ( 15 ) is disposed at a rear section between the air storage chamber ( 13 ) and the barrel ( 11 ). The front end of the air storage chamber ( 13 ) is connected to a high-pressure flask ( 16 ) to input high-pressure air into the air storage chamber ( 13 ). The frame ( 1 ) further comprises a trigger ( 17 ) and a three-way valve ( 18 ). The three-way valve ( 18 ) is controlled by the trigger ( 17 ) to activate. The three-way valve ( 18 ) comprises an air inlet hole ( 181 ) interconnecting with an air inlet way ( 182 ), an air outlet hole ( 183 ) interconnecting with an air outlet way ( 184 ) for low-pressure air to pass through, and a rod ( 185 ) to control the passage between the an air inlet hole ( 181 ) and the air outlet hole ( 183 ).
The spool ( 2 ) is disposed in the barrel ( 11 ). The spool ( 2 ) comprises a sleeve ( 21 ) having an opening ( 211 ) at a front end thereof. A piston ( 22 ) is provided in the sleeve ( 21 ) and is adapted to block the opening ( 211 ) of the sleeve ( 21 ). A spring ( 221 ) is provided between the piston ( 22 ) and the sleeve ( 21 ). A through hole ( 23 ) is disposed at the front section of the sleeve ( 21 ) to penetrate its outer edge, and another through hole ( 24 ) is disposed at the front section of the piston ( 22 ) to penetrate its outer edge. A through channel ( 25 ) is formed at the rear section of the spool ( 2 ).
The low pressure regulator ( 3 ) is threaded into the rear end of the air storage chamber ( 13 ). Both the low pressure regulator ( 3 ) and the air storage chamber ( 13 ) are formed with threads for threaded connection. The low pressure regulator ( 3 ) comprises a groove ( 31 ) on its circumference that interconnects with the through channel ( 25 ) and the air outlet way ( 184 ). The front end of the low pressure regulator ( 3 ) has a block ( 32 ) thereon.
To operate the present invention, as shown in FIG. 2 , pressurized air stored in the air flask ( 16 ) fills up the air storage chamber ( 13 ) and enters into the sleeve ( 21 ) of the spool ( 2 ) through the port ( 14 ). Due to the opening ( 211 ) of the sleeve ( 21 ) blocked by the piston ( 22 ), the pressurized air continues gathering in the spool ( 2 ). As shown in FIG. 3 , upon a paintball (B) drops into the front end of the barrel ( 11 ), the user may pull the trigger ( 17 ) which drives the rod ( 185 ) of the three-way valve ( 18 ) to move forward and then opens the blockage between the air inlet hole ( 181 ) and the air outlet hole ( 183 ), allowing the low pressure air to pass through the air inlet way ( 182 ), the air inlet hole ( 181 ), the air inlet hole ( 183 ), the air outlet way ( 184 ), the groove ( 31 ) of the low pressure regulator ( 3 ), and the key hole ( 15 ) into the through channel ( 25 ) of the spool ( 2 ). The air in the through channel ( 25 ) pushes the piston ( 22 ) to slide along the sleeve ( 21 ) forward and compresses the spring ( 221 ). When the piston ( 22 ) is moving forward, the paintball (B) will be pushed to the triggering position, and the opening ( 211 ) is cleared from blocking, as shown in FIG. 4 . The high pressurized air accumulating in the spool ( 2 ) at this time will be discharged at a high speed from the opening ( 211 ) and spurred out of the through hole ( 24 ) of the piston ( 22 ) to fire the paintball (B). After the paintball (B) is shot, the spring ( 221 ) urges the piston ( 22 ) to return to its original position to block the opening ( 211 ) again for next movement.
To avoid triggering accidentally, as shown in FIG. 5 , a hand tool (C) may be adapted to turn the low pressure regulator ( 3 ), so that the block ( 32 ) at the front end of the low pressure regulator ( 3 ) may be slid within the air storage chamber ( 13 ) till the port ( 14 ) is blocked to cut the high pressurized air in the air storage chamber ( 13 ) from entering into the barrel ( 11 ) and firing the paintball (B). | A paintball gun utilizes pressurized air to fire a paintball to avoid using a spool protruding from a barrel to fire the paintball which may pinch the user's finger, accidentally. The paintball gun also uses a low pressure regulator to seal a port of the barrel to block pressurized air from entering into the barrel to prevent triggering the gun and damaging others. | 5 |
BACKGROUND OF THE INVENTION
The present invention relates to a combustion sensing apparatus having an air fuel ratio sensor incorporating a solid electrolyte such as stabilized zirconia and suited for use in the detection of oxygen concentration in a flame.
In the use of combustion sensor, it is necessary to expose the cathode and anode formed on a solid electrolyte separately to the atmosphere as a reference gas and to the gas to be measured, respectively. In order to make sure of the separation, the solid electrolyte is shaped in a tubular form opened at its both ends of closed only at one end thereof.
The work for forming an anode on the inner surface of such a tubular combustion sensor has to be conducted manually, regardless of whether the tubular body of the sensor is closed at its one end or opened at its both ends. In addition, the contruction of the lead from the electrode is complicated. For these reasons, the cost of production is raised uneconomically and the reliability is deteriorated undesirably.
In the case of the air-fuel ratio sensor, the cathode and anode are produced in the form of porous films, and the catalytic action performed by the porous films largely affects the output characteristics of the sensor. Therefore, a severe control is necessary for the control of the porosity, thickness and other factors of the anode formed on the inner peripheral surface of the cylindrical sensor body. Actually, however, the major portion of the anode cannot be checked visually. This imposes various problems.
The production cost is ruled also by the amount of platinum or the like precious metal alloy used as the material of the electrodes formed on the inner and outer surface of the solid electrolyte tube. Although effort is concentrated to reduce the amount of use of such a precious metal alloy, as a matter of fact, the formation of the electrodes is very difficult so that the alloy is wastefully consumed to form the electrode or leads covering unnecessarily large area, resulting in a raised cost of production.
SUMMARY OF THE INVENTION
Accordingly, an object of the invention is to provide a simple and reliable combustion sensing apparatus.
To this end, according to the invention, there is provided a combustion sensing apparatus comprising a cathode disposed in the vicinity of a burner and formed on the surface of a solid electrolyte subjected to the flow of hot exhaust gas, and an anode formed on the surface of the solid electrolyte subjected to an atmosphere of a reference gas, wherein the improvement comprises that the solid electrolyte is shaped to have a tabular form.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partly sectioned side elevational view of the combustion sensor constructed in accordance with an embodiment of the invention;
FIGS. 2a and 2b are side elevational views as viewed from both sides of an example of a sensor element;
FIG. 3 is a sectional view taken along the line III--III of FIG. 2a;
FIG. 4 is a plan view of the combustion sensor; and
FIG. 5 is a circuit diagram of a circuit connected to the combustion sensor.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention will be fully understood from the following description of the preferred embodiment.
Referring first to FIG. 1 showing particularly the combustion sensing section of a combustion sensing apparatus in accordance with the invention, a pilot burner 2 mounted on a base 1 is adapted to be supplied with a fuel from the lower side of the base 1. The pilot burner 2 has a nozzle 2A extending in parallel with the base 1 and adapted to jet a flame 3. A socket 4 is fixed by a screw 4A to the portion of the base 1 in front of the nozzle 2A. The socket 4 has a pair of electrodes 5A and 5B biased toward each other and led to the lower side of the base 1. A sensor element 6 is clamped between the electrodes 5A and 5B of the socket 4. The sensor element 6 has a tabular form and is disposed such that the upper portion of one side of the sensor element 6 is contacted by the flame jetted from the nozzle 2A. In consequence, the sensor element 6 is heated up to an operating temperature ranging between 300° and 1000° C.
As will be seen from FIGS. 2a and 2b, the sensor element 6 has a substrate 7 having a tabular form and made from a solid electrolytic material, such as stabilized zirconia, and is covered at its one side by an anode plate 8 as shown in FIG. 2a. The anode plate 8 consists of a porous film of, for example, platinum and is formed by vacuum evaporation or the like method. The anode plate 8 is provided at its one end with an anode lead plate 9 made of a material which serves merely as an electrically conductive body. For instance, this lead plate 9 can be formed by applying and firing platinum paste. On the other side of the substrate 7, a cathode plate 10 and a cathode lead 11 are formed in the same manner as the opposite side, as will be seen from FIG. 2a. A protective film 12 is formed to cover the major part of the cathode plate 10 connected to the cathode lead 11. The protective film 12 is a porous film so that it can function also as a catalyst while serving as a protector for preventing the cathode plate 10 from being contacted directly by the flame 3. The sensor element 6 shown in FIG. 2a has a sectional shape as shown in FIG. 3 which is a sectional view taken along the line III--III of FIG. 2a.
Referring back to FIG. 1, the sensor element 6 is arranged such that the protective film 12 faces the nozzle 2A and is contacted at its anode lead plate 9 and cathode lead plate 11 by the electrodes 5A and 5B, respectively.
A shielding member 13 is disposed at the rear side of the sensor element 6. As will be seen from FIG. 4, the shielding member 13 is composed of a substantially U-shaped member turned sideways, so that a space is formed between the shielding member 13 and the sensor element 6 for permitting air to flow therein in the vertical direction. The shielding member is supported by the screw 4A for fixing the socket 4 to the base 1. The shielding member 13 effectively prevents the flame 3 from stretching behind the sensor element, i.e. to the same side as the anode. An upward flow of air is produced due to a convection caused by the heat, in the space adjacent to the anode and surrounded by the shielding member 13. This air contains about 20% of oxygen and serves as the reference gas in relation to the hot combustion gas which flows at the same side as the cathode. Blades 14 provided at the inner side of lower end of the shielding member 13 restrict the flow of air, thereby to prevent excessive cooling of the sensor element by the flow of air.
As will be seen from FIG. 5, the pilot burner 2 is adapted to be supplied with fuel through a main pipe 16 via a solenoid valve 15. This main pipe 16 is branched at the downstream side of the solenoid valve 15 into two pipes one of which leads to the pilot burner 12 while the other leads to a main burner. The solenoid valve 15 is adapted to be actuated to open and close by a solenoid coil 17 which is under the control of the output from a controller 18 adapted to operate in response to the output from the sensor element 6.
For instance, when the mixture is too rich, i.e. the oxygen content is too small, the sensor element 6 produces an electromotive power of 0.5 to 0.8 V which serves to operate the controller 18 thereby to close the solenoid valve 15. On the other hand, when the fire on the pilot burner 2 is put off, the sensor element 6 is not heated so that the internal resistance, which is 1 KΩ or less before the heating, is drastically increased to 10 MΩ or higher. Upon detect of the increase of the resistance, the controller 18 operates to close the solenoid valve 15.
In the described embodiment of the invention, the formation of the anode and cathode on both sides of the sensor element 6 can be made in quite an easy manner by a known method such as evaporation or printing, thanks to the tabular form of the sensor element. Most conveniently, the solid electrolyte, as the substrate, is formed by, for example, rolling in a tabular form having a large area and, after forming the electrodes on respective surfaces, cut into independent sensor elements by means of a laser scriber or a diamond cutter.
In addition, the tabular form of the sensor element 6 affords an easy visual check of the anode and cathode which in turn permits an easier control of the porosity, thickness and other factors of the anode and cathode.
Furthermore, since a sufficiently large space is preserved above the region in which the electrode is to be formed, it is possible to form the electrode precisely on the required region to eliminate wasteful use of the precious metal alloy, thereby to lower the cost of production.
The separation of reference gas and the atmosphere from each other can be made at a high reliability because the stretching of the flame 3 into the anode side is avoided by the presence of the shielding member 13.
In the described embodiment of the invention, the extension of the flame into the anode side, which may occur due to the tabular form of the sensor element 6, is prevented by the shielding member 13. The shielding member, however, is not essential and may be dispensed with provided that the flame 3 does not have such an intensity as to extend behind the sensor element 6.
In the described embodiment, the anode is formed on one side of the solid electrolyte while the cathode is formed on the other side of the latter. This arrangement, however, is not always necessary. Namely, in the case where the shielding member 13 can be neglected, it is possible to arrange such that the cathode and the anode are formed on the same side of the solid electrolyte separately from each other and disposed at portions contactable and not contactable with the flame, respectively.
As has been described, according to the invention, it is possible to obtain a combustion sensing apparatus having a simplified construction and operable at a high reliability.
Although the invention has been described through a specific embodiment, it is to be noted that the described embodiment is not exclusive and various changes and modifications may be imparted thereto without departing from the scope of the invention which is limited solely by the appended claims. | A combustion sensing apparatus having a solid electrolyte disposed in the vicinity of a burner and having a tabular form. Thanks to the tabular form of the solid electrolyte, the production of the apparatus is very much facilitated and the areas occupied by the anode and cathode are minimized. The construction of the apparatus as a whole is simplified and the reliability of the same is improved remarkably. In addition, the cost of production is lowered advantageously. | 5 |
This application claims benefit of U.S. Provisional Application 60/420,149 filed Oct. 22, 2002.
TECHNICAL FIELD
The present invention relates generally to methods of making nonwoven fabrics, and more particularly, to a method of manufacturing a nonwoven fabric exhibiting a durable three-dimensional image, permitting use of the fabric in secondary carpet backing systems so as to reduce deformation under normal use (walking) and improve the amount of coverage provided to the secondary carpet backing system applications.
BACKGROUND OF THE INVENTION
The production of conventional textile fabrics is known to be a complex, multi-step process. The production of fabrics from staple fibers begins with the carding process whereby the fibers are opened and aligned into a feedstock referred to in the art as “sliver”. Several strands of sliver are then drawn multiple times on a drawing frames to; further align the fibers, blend, improve uniformity and reduce the sliver's diameter. The drawn sliver is then fed into a roving frame to produce roving by further reducing its diameter as well as imparting a slight false twist. The roving is then fed into the spinning frame where it is spun into yarn. The yarns are next placed onto a winder where they are transferred into larger packages. The yarn is then ready to be used to create a fabric.
For a woven fabric, the yarns are designated for specific use as warp or fill yarns. The fill yarns (which run on the y-axis and are known as picks) are taken straight to the loom for weaving. The warp yarns (which run on the x-axis and are known as ends) must be further processed. The large packages of yarns are placed onto a warper frame and are wound onto a section beam were they are aligned parallel to each other. The section beam is then fed into a slasher where a size is applied to the yarns to make them stiffer and more abrasion resistant, which is required to withstand the weaving process. The yarns are wound onto a loom beam as they exit the slasher, which is then mounted onto the back of the loom. The warp yarns are threaded through the needles of the loom, which raises and lowers the individual yarns as the filling yarns are interested perpendicular in an interlacing pattern thus weaving the yarns into a fabric. Once the fabric has been woven, it is necessary for it to go through a scouring process to remove the size from the warp yarns before it can be dyed or finished. Currently, commercial high-speed looms operate at a speed of 1000 to 1500 picks per minute, where a pick is the insertion of the filling yarn across the entire width of the fabric. Sheeting and bedding fabrics are typically counts of 80×80 to 200×200, being the ends per inch and picks per inch, respectively. The speed of weaving is determined by how quickly the filling yarns are interlaced into the warp yarns, therefore looms creating bedding fabrics are generally capable of production speeds of 5 inches to 18.75 inches per minute.
In contrast, the production of nonwoven fabrics from staple fibers is known to be more efficient than traditional textile processes, as the fabrics are produced directly from the carding process.
Nonwoven fabrics are suitable for use in a wide variety of applications where the efficiency with which the fabrics can be manufactured provides a significant economic advantage for these fabrics versus traditional textiles. However, nonwoven fabrics have commonly been disadvantaged when fabric properties are compared to conventional textiles, particularly in terms of resistance to elongation, in applications where both transverse and co-linear stresses are encountered. Hydroentangled fabrics have been developed with improved properties, by the formation of complex composite structures in order to provide a necessary level of fabric integrity. Subsequent to entanglement, fabric durability has been further enhanced by the application of binder compositions and/or by thermal stabilization of the entangled fibrous matrix.
Nonwoven composite structures typically improve physical properties, such as elongation, by way of incorporation of a support layer or scrim. The support layer material can comprise an array of polymers, such as polyolefins, polyesters, polyurethanes, polyamides, and combinations thereof, and take the form of a film, fibrous sheeting, or grid-like meshes. Metal screens, fiberglass, and vegetable fibers are also utilized as support layers. The support layer is commonly incorporated either by mechanical or chemical means to provide reinforcement to the composite fabric. Reinforcement layers, also referred to as a “scrim” material, are described in detail in U.S. Pat. No. 4,636,419, which is hereby incorporated by reference. The use of scrim material, more particularly, a spunbond scrim material is known to those skilled in the art.
Spunbond material comprises continuous filaments typically formed by extrusion of thermoplastic resins through a spinneret assembly, creating a plurality of continuous thermoplastic filaments. The filaments are then quenched and drawn, and collected to form a nonwoven web. Spunbond materials have relatively high resistance to elongation and perform well as a reinforcing layer or scrim. U.S. Pat. No. 3,485,706 to Evans, et al., which is hereby incorporated by reference, discloses a continuous filament web with an initial random staple fiber batt mechanically attached via hydroentanglement, then a second random staple fiber batt is attached to the continuous filament web, again, by hydroentanglement. A continuous filament web is also utilized in U.S. Pat. Nos. 5,144,729; 5,187,005; and 4,190,695. These patents include a continuous filament web for reinforcement purposes or to reduce elongation properties of the composite.
More recently, hydroentanglement techniques have been developed which impart images or patterns to the entangled fabric by effecting hydroentanglement on three-dimensional image transfer devices. Such three-dimensional image transfer devices are disclosed in U.S. Pat. No. 5,098,764, which is hereby incorporated by reference; with the use of such image transfer devices being desirable for providing a fabric with enhanced physical properties as well as functional dimension.
A three-dimensionally imaged nonwoven fabric exhibits a combination of specific physical characteristics so as to be beneficial in carpet backing applications. Further, three-dimensionally imaged nonwoven fabrics used in industrial applications require sufficient resistance to elongation so as to resist deformation of the image when the fabric is converted into a final end-use article and when used in the final application.
Heretofore, nonwoven fabrics have been advantageously employed for manufacture of secondary carpet backing. Generally, nonwoven fabrics employed for this type of application have been entangled and integrated by mechanical needle-punching, sometimes referred to as “needle-felting”, which entails repeated insertion and withdrawal of barbed needles through a fibrous web structure. While this type of processing acts to integrate the fibrous structure and lend integrity thereto, the barbed needles inevitably shear large numbers of the constituent fibers, and undesirably create perforations in the fibrous structure, which act to compromise the integrity of the carpet backing and can inhibit proper coverage. Needle-punching can also be detrimental to the strength of the resultant fabric, requiring that a suitable nonwoven fabric have a higher basis weight in order to exhibit sufficient strength for secondary carpet backing applications.
Notwithstanding various attempts in the prior art to develop a secondary carpet backing for carpet systems, a need continues to exist for a nonwoven fabric, which provides a pronounced image for.
SUMMARY OF THE INVENTION
The present invention is directed to a method of forming a nonwoven fabric, which exhibits a pronounced durable three-dimensional image, permitting use of the fabric in secondary carpet backing of carpet backing systems so as to reduce deformation under normal use (walking) and provide better coverage in carpet system applications. In particular, the present invention contemplates that a fabric is formed from a precursor web comprising a spunbond and/or cast scrim, which when subjected to hydroentanglement on an imaging surface, an enhanced product is achieved. By formation in this fashion, hydroentanglement of the precursor web results in a more pronounced three-dimensional image; an image that is durable to abrasion and distortion.
In accordance with the present invention, a method of making a nonwoven fabric embodying the present invention includes the steps of providing a precursor web comprising a fibrous matrix. While use of staple length fibers is typical, the fibrous matrix may comprise substantially continuous filaments. In a particularly preferred form, the fibrous matrix comprises staple length fibers, which are carded and cross-lapped to form a precursor web. In one embodiment of the present invention, the precursor web is subjected to pre-entangling on a foraminous-forming surface prior to juxtaposition of a continuous filament and/or cast scrim and subsequent three-dimensional imaging. Alternately, one or more layers of fibrous matrix are juxtaposed with one or more continuous filament and/or cast scrims, then the layered construct is pre-entangled to form a precursor web which is imaged directly, or subjected to further fiber, filament, support layers, or scrim layers prior to imaging.
The present method further contemplates the provision of a three-dimensional image transfer device having a movable imaging surface. In a typical configuration, the image transfer device may comprise a drum-like apparatus, which is rotatable with respect to one or more hydroentangling manifolds.
The precursor web is advanced onto the imaging surface of the image transfer device. Hydroentanglement of the precursor web is effected to form a three-dimensionally imaged fabric. Significantly, the incorporation of at least one continuous filament or cast scrim acts to focus the fabric tension therein, allowing for improved imaging of the staple fiber layer or layers, and resulting in a more pronounced three-dimensional image.
Subsequent to hydroentanglement, the three-dimensionally imaged fabric may be subjected to one or more variety of post-entanglement treatments. Such treatments may include application of a polymeric binder composition, mechanical compacting, application of additives or electrostatic compositions, and like processes.
A further aspect of the present invention is directed to a method of forming a durable nonwoven fabric, which exhibits a pronounced and resilient three-dimensionality, while providing the necessary resistance to distortion, to facilitate use in a wide variety of industrial applications. The fabric exhibits a high degree of fiber retention, thus permitting its use in those applications in which the fabric is used as a secondary carpet backing in carpet backing systems. Further, the scrim aids in preventing the distortion of the imprinted image upon the application of tension to the composite fabric during routine processing and use.
A method of making the present durable nonwoven fabric comprises the steps of providing a precursor web, which is subjected to hydroentangling. The precursor web is formed into a three-dimensionally imaged nonwoven fabric by hydroentanglement on a three-dimensional image transfer device. The image transfer device defines three-dimensional elements against which the precursor web is forced during hydroentanglement, whereby the fibrous constituents of the web are imaged by movement into regions between the three-dimensional elements and surface asperities of the image transfer device.
In the preferred form, the precursor web is hydroentangled on a foraminous surface prior to hydroentangling on the imaging surface. This pre-entangling of the precursor web acts to integrate the fibrous components of the web, but does not impart a three-dimensional image as can be achieved through the use of the three-dimensional image transfer device.
Optionally, subsequent to three-dimensional imaging, the imaged nonwoven fabric can be treated with a performance or aesthetic modifying composition to further alter the fabric structure or to meet end-use article requirements. A polymeric binder composition can be selected to enhance durability characteristics of the fabric or an antimicrobial additive may be used utilized to deter the growth of fungus and mold.
Other features and advantages of the present invention will become readily apparent from the following detailed description, the accompanying drawings, and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic view of an apparatus for manufacturing a durable nonwoven fabric, embodying the principles of the present invention.
DETAILED DESCRIPTION
While the present invention is susceptible of embodiment in various forms, there is shown in the drawings, and will hereinafter be described, a presently preferred embodiment of the invention, with the understanding that the present disclosure is to be considered as an exemplification of the invention, and is not intended to limit the invention to the specific embodiment illustrated.
The present invention is directed to a method of forming a durable three-dimensionally imaged nonwoven suitable for use as secondary carpet backing for carpet backing systems wherein the three-dimensional imaging of the fabrics is enhanced by the incorporation of at least one continuous filament support layer and/or cast scrim. Enhanced imaging can be achieved utilizing various techniques, one such technique involves minimizing and eliminating tension in the overall precursor web as the web is advanced onto a moveable imaging surface of the image transfer device, as represented by co-pending U.S. patent application, Ser. No. 60/344,259 to Putnam et al, entitled Nonwoven Fabrics Having a Durable Three - Dimensional Image , and filed on Dec. 28, 2002, which is hereby incorporated by reference. By use of a continuous filament support layer or scrim, cast scrim, or the combination thereof, enhanced fiber entanglement is achieved, with the physical properties, both aesthetic and mechanical, of the resultant fabric being desirably enhanced. It is reasonably believed that the internal support of the precursor web provided by the support layer or scrim, as the precursor web is advanced onto the image transfer device, desirably acts to focus tension to the support layer or scrim. Without tension, the fibers or filaments of the fibrous matrix, from which the precursor web is formed, can more easily move and shift during hydroentanglement, thus resulting in improved three-dimensional imaging on the image transfer device. A more clearly defined and durable image is achieved.
With reference to FIG. 1, therein is illustrated an apparatus for practicing the present method for forming a nonwoven fabric. The fabric is formed from a fibrous matrix, which typically comprises staple length fibers, but may comprise substantially continuous filaments. The fibrous matrix is preferably carded and cross-lapped to form a fibrous batt, designated F. In a current embodiment, the fibrous batt comprises 100% cross-lap fibers, that is, all of the fibers of the web have been formed by cross-lapping a carded web so that the fibers are oriented at an angle relative to the machine direction of the resultant web. U.S. Pat. No. 5,475,903, hereby incorporated by reference, illustrates a web drafting apparatus.
A continuous filament support layer or scrim, cast scrim, or a combination thereof, is then placed in face to face to face juxtaposition with the fibrous web and hydroentangled to form precursor web P. Alternately, the fibrous web can be hydroentangled first to form precursor web P, and subsequently, at least one support layer or scrim is applied to the precursor web, and the composite construct optionally further entangled with non-imaging hydraulic manifolds, then imparted a three-dimensional image on an imaging surface.
FIG. 1 illustrates a hydroentangling apparatus for forming nonwoven fabrics in accordance with the present invention. The apparatus includes a foraminous-forming surface in the form of belt 10 upon which the precursor web P is positioned for pre-entangling by entangling manifold 12 . Pre-entangling of the precursor web, prior to three-dimensional imaging, is subsequently effected by movement of the web P sequentially over a drum 14 having a foraminous-forming surface, with entangling manifold 16 effecting entanglement of the web. Further entanglement of the web is effected on the foraminous forming surface of a drum 18 by entanglement manifold 20 , with the web subsequently passed over successive foraminous drums 20 , for successive entangling treatment by entangling manifolds 24 , 24 ′.
The entangling apparatus of FIG. 1 further includes a three-dimensional imaging drum 24 comprising a three-dimensional image transfer device for effecting imaging of the now-entangled precursor web. The image transfer device includes a moveable imaging surface which moves relative to a plurality of entangling manifolds 26 which act in cooperation with three-dimensional elements defined by the imaging surface of the image transfer device to effect imaging and patterning of the fabric being formed.
The present invention contemplates that the support layer or scrim be any such suitable continuous filament nonwoven material, cast scrim, or combination thereof, including, but not limited to a spunbond fabric, a spunbond-meltblown laminate, or a spunbond-spunbond laminate, which exhibit low elongation performance. A particularly preferred embodiment of support layer or scrim is a thermoplastic spunbond nonwoven fabric. The support layer may be maintained in a wound roll form, which is then continuously fed into the formation of the precursor web, and/or supplied by a direct spinning beam located in advance of the three-dimensional imaging drum 24 .
Manufacture of a durable nonwoven fabric embodying the principles of the present invention is initiated by providing the fibrous matrix, which can include the use of staple length fibers, continuous filaments, and the blends of fibers and/or filaments having the same or different composition. Fibers and/or filaments are selected from natural or synthetic composition, of homogeneous or mixed fiber length. Suitable natural fibers include, but are not limited to, cotton, wood pulp and viscose rayon. Synthetic fibers, which may be blended in whole or part, include thermoplastic and thermoset polymers. Thermoplastic polymers suitable for blending with dispersant thermoplastic resins include polyolefins, polyamides and polyesters. The thermoplastic polymers may be further selected from homopolymers; copolymers, conjugates and other derivatives including those thermoplastic polymers having incorporated melt additives or surface-active agents. Staple lengths are selected in the range of 0.25 inch to 10 inches, the range of 1 to 3 inches being preferred and the fiber denier selected in the range of 1 to 22, the range of 1.2 to 6 denier being preferred for general applications. The profile of the fiber and/or filament is not a limitation to the applicability of the present invention.
EXAMPLES
Comparative Example 1
Using a forming apparatus as illustrated in FIG. 1, a nonwoven fabric was made by providing a precursor web comprising 100 weight percent polypropylene fibers. The web had a basis weight of 3 ounces per square yard (plus or minus 7%). The precursor web was 100% carded and cross-lapped, with a draft ratio of 2.5 to 1.
Prior to three-dimensional imaging of the precursor web, the web was entangled by a series of entangling manifolds such as diagrammatically illustrated in FIG. 1 . FIG. 1 illustrates disposition of precursor web P on a foraminous forming surface in the form of belt 10 , with the web acted upon by an entangling manifold 12 . The web then passes sequentially over a drum 14 having a foraminous forming surface, for entangling by entangling manifold 16 , with the web thereafter directed about the foraminous forming surface of a drum 18 for entangling by entanglement manifold 20 . The web is thereafter passed over successive foraminous drums 22 , with successive entangling treatment by entangling manifolds 24 , 24 ′. In the present examples, each of the entangling manifolds included 120 micron orifices spaced at 42.3 per inch, with the manifolds successively operated at 100, 300, 700, and 1300 pounds per square inch, with a line speed of 45 yards per minute. A web having a width of 72 inches was employed.
The entangling apparatus of FIG. 1 further includes a three-dimensional imaging drum 24 comprising a three-dimensional image transfer device for effecting imaging and patterning of the now-entangled precursor web. The entangling apparatus includes a plurality of entangling manifolds 26 , which act in cooperation with the three-dimensional image transfer device of drum 24 to effect patterning of the fabric. In the present example, the imaging manifolds 26 were successively operated at 2800, 2800, and 2800 pounds per square inch, at a line speed which was the same as that used during pre-entanglement.
Example 1
A three-dimensionally imaged nonwoven fabric was manufactured by a process as described in Comparative Example 1, wherein in the alternative, and in accordance with the present invention, a lighter 1.5 ounce per square yard polyester staple fiber web was juxtaposed with a 1.5 ounce polyester spunbond web of approximately 2.0 denier. The staple fiber web/spunbond web layered matrix was then subjected to equivalent hydraulic pressures as described in Comparative Example 1.
The imaged nonwoven fabrics made in accordance with the present invention exhibit greater three-dimensional image clarity and are more pronounced than the image imparted to equivalent basis weight materials without the support layer or scrim. Imaged nonwoven fabrics, such as Example 1, exhibit a significantly reduced elongation performance, resulting in improved image retention during mechanical processing and use.
The material of the present invention may be utilized as a secondary carpet backing as well as provide for backing material of various floor systems, including floating laminate floor systems, and other end use products where a three-dimensionally imaged nonwoven fabric can be employed. Other end uses include; fabrication into acoustic wall systems, automotive applications, wet or dry hard surface wipes, which can be readily hand-held for cleaning and the like, protective wear for industrial uses, such as gowns or smocks, shirts, bottom weights, lab coats, face masks, and the like, and protective covers, including covers for vehicles such as cars, trucks, boats, airplanes, motorcycles, bicycles, golf carts, as well as covers for equipment often left outdoors like grills, yard and garden equipment, such as mowers and roto-tillers, lawn furniture, floor coverings, table cloths and picnic area covers.
From the foregoing, it will be observed that numerous modifications and variations can be affected without departing from the true spirit and scope of the novel concept of the present invention. It is to be understood that no limitation with respect to the specific embodiments illustrated herein is intended or should be inferred. The disclosure is intended to cover, by the appended claims, all such modifications as fall within the scope of the claims. | The present invention is directed to a method of forming a nonwoven fabric, which exhibits a pronounced durable three-dimensional image, permitting use of the fabric in secondary carpet backing of carpet backing systems so as to reduce deformation under normal use (walking) and provide better coverage in carpet system applications. In particular, the present invention contemplates that a fabric is formed from a precursor web comprising a spunbond and/or cast scrim, which when subjected to hydroentanglement on an imaging surface, an enhanced product is achieved. By formation in this fashion, hydroentanglement of the precursor web results in a more pronounced three-dimensional image; an image that is durable to abrasion and distortion. | 3 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention generally relates to an analog multiplying circuit and a variable gain amplifying circuit. More specifically, the present invention is directed to an analog multiplying circuit for multiplying two analog signals with each other in a modulating/demodulating circuit of a wireless appliance so as to perform a frequency conversion of the multiplied analog signal, and also to a variable gain amplifying circuit.
[0003] 2. Description of the Related Art
[0004] Very recently, a large number of circuits for processing high frequency (radio frequency) signals are used in wireless appliances, in particular, a great number of such circuits as amplifiers and frequency converters are employed in these wireless appliances. On the other hand, power supply voltages applied in order to operate these circuits are gradually lowered. For instance, in general, the power supply voltage Vcc was selected to be 4.8 V a several years ago. In current wireless appliances, generally speaking, the power supply voltage Vcc is selected to be 2.6 V.
[0005] [0005]FIG. 9 is a circuit diagram of the conventional dual balanced type analog multiplying circuit (Gilbert cell mixer) constituted by bipolar transistors. In this analog multiplying circuit, first analog differential signals V 1 p and V 1 n are applied to both a common base of transistors Q 2 and Q 3 , and a common base of transistors Q 1 and Q 4 of two sets of differential pairs Q 1 -Q 2 and Q 3 -Q 4 which employ the transistors Q 1 through Q 4 . A collector of the transistor Q 1 is connected to a collector of the transistor Q 3 so as to form an output terminal Vop, and a collector of the transistor Q 2 is connected to a collector of the transistor Q 4 so as to form an output terminal Von. Also, these collectors are connected via load resistors R 1 and R 2 to a power supply voltage Vcc. To an emitter of the differential pair Q 1 -Q 2 and an emitter of the differential pair Q 3 -Q 4 , collectors of transistors Q 5 and Q 6 are connected, respectively. Second analog differential signals V 2 p and V 2 n are applied to bases of the transistors Q 5 and Q 6 . An emitter of the transistor Q 5 and an emitter of the transistor Q 6 are connected to a collector of a transistor Q 7 and a collector of a transistor Q 8 , which constitute a current source of a current value Ics, respectively. A feedback resistor Re capable of linearizing a second analog signal input unit is connected between the emitter of the transistor Q 5 and the emitter of the transistor Q 6 . A bias voltage Vb is applied to both a base of a transistor Q 7 and a base of a transistor Q 8 .
[0006] Assuming now that a voltage of a base-to-emitter of the transistor Q 5 is equal to Vbe 5 , and a voltage of a base-to-emitter of the transistor Q 6 is equal to Vbe 6 , both an output current I 3 of the transistor Q 5 and an output current I 4 of the transistor Q 6 , which constitute a first differential amplifier, may be expressed by the following formulae (1) and (2):
I 3 =Ics+(V 2 p−V 2 n−Vbe 5 +Vbe 6 )/ Re (1)
I 4 =Ics−(V 2 p−V 2 n−Vbe 5 +Vbe 6 )/ Re (2)
[0007] As a result, an output current 2*ΔI=I 3 −I 4 is represented by the following formula(3):
2*ΔI=I 3 −I 4 =2*(V 2 p−V 2 n−Vbe 5 +Vbe 6 )/ Re= 2*{V 2 p−V 2 n+ Vt*ln (I 4 /I 3 )}/ Re (3)
[0008] Note that the voltages between the bases and the emitters of the transistors Q 5 and Q 6 are assumed as:
[0009] Vbe 5 =Vt*ln(I 3 /Is),
[0010] Vbe 6 =Vt*ln(I 4 /Is)
[0011] Also, assuming now that a current flowing through the load resistor R 1 is I 1 , a current flowing through the load resistor R 2 is I 2 , and symbol Vt is a thermal voltage, a differential output I 1 -I 2 may be expressed by the below-mentioned formula (4) if the base current is neglected:
I 1 -I 2 =2*ΔI*tan h {(V 1 p−V 1 n)/2 Vt}= 2*{V 2 p−V 2 n+ Vt* 1 n (I 4 /I 3 )}/ Re *tan h {(V 1 p−V 1 n)/2 Vt} (4)
[0012] Furthermore, when V 1 p−V 1 n<<Vt, the below-mentioned formula can be approximatively satisfied:
tan h {(V 1 p−V 1 n)/2 Vt }=(V 1 p−V 1 n)/2 Vt.
[0013] Then, as expressed in the following formula (5), two signals are multiplied with each other:
I 1 -I 2 =2*{(V 2 p−V 2 n)+ Vt*In (I 4 /I 3 )}/ Re *{(V 1 p−V 1 n)/2 Vt} (5)
[0014] In the conventional circuit shown in FIG. 6, a total number of longitudinally-stacked stages of the transistors is selected to be 3 stages. As a consequence, a minimum power supply voltage Vcc(min) required in such a case that silicon bipolar transistors are used must be higher than, or equal to 2.6 V in order that both the voltages between the bases and the emitters of the transistors, and also the amplitude voltages of the input/output signals can be secured, as the power supply voltage Vcc(min).
[0015] However, since the conventional analog multiplying circuit cannot be operated under such a power supply voltage lower than, or equal to 2.6 V, this conventional analog multiplying circuit owns the problem that this analog multiplying circuit cannot be used in the presently available wireless appliances having the power supply voltage of 2.6 V.
SUMMARY OF THE INVENTION
[0016] The present invention has been made to solve the above-explained problem, and therefore, has an object to provide such an analog multiplying circuit operable in a highly linear mode under low power supply voltage lower than, or equal to 2.6 V.
[0017] To solve the above-explained problem, an analog multiplying circuit, according to the present invention, is featured by such an analog multiplying circuit comprising: a first differential pair constructed of a first transistor and a second transistor, the emitters of which are commonly connected to each other; a second differential pair constructed of a third transistor and a fourth transistor, the emitters of which are commonly connected to each other; a first input terminal connected to a commonly-connected base of the second transistor and the third transistor; a second input terminal connected to a commonly-connected base of the first transistor and the fourth transistor; a first output terminal connected to a commonly-connected collector of the first transistor and the third transistor; a second output terminal connected to a commonly-connected collector of the second transistor and the fourth transistor; a first resistor connected between the first output terminal and a power supply; a second resistor connected between the output terminal and the power supply; a fifth transistor, the collector of which is connected to the commonly-connected emitter of the first differential pair; a sixth transistor, the collector of which is connected to the commonly-connected emitter of the second differential pair; a third resistor connected between an emitter of the fifth transistor and the ground; a fourth resistor connected between an emitter of the sixth transistor and the ground; first input means connected to a base of the fifth transistor; and second input means connected to a base of the sixth transistor; wherein: the first input means is arranged by first current generating means, first current mirror means constituted by both the fifth transistor and a seventh transistor, a fifth resistor connected between an emitter of the seventh transistor and the ground, and a third input terminal connected to the emitter of the seventh transistor; and the second input means is arranged by second current generating means, second current mirror means constituted by both the sixth transistor and an eighth transistor, a sixth resistor connected between an emitter of the eighth transistor and the ground; and a fourth input terminal connected to the emitter of the eighth transistor. Since such a circuit arrangement is employed, the analog multiplying circuit can be operated under low power supply voltages.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] [0018]FIG. 1 is a circuit diagram of an analog multiplying circuit according to a first embodiment mode of the present invention.
[0019] [0019]FIG. 2 is a circuit diagram of a variable gain amplifying circuit according to the first embodiment mode of the present invention.
[0020] [0020]FIG. 3 is a circuit diagram of an analog multiplying circuit according to a second embodiment mode of the present invention.
[0021] [0021]FIG. 4 is a circuit diagram of a variable gain amplifying circuit according to the second embodiment mode of the present invention.
[0022] [0022]FIG. 5 is a circuit diagram of an analog multiplying circuit according to a third embodiment mode of the present invention.
[0023] [0023]FIG. 6 is a circuit diagram of a variable gain amplifying circuit according to the third embodiment mode of the present invention.
[0024] [0024]FIG. 7 is a circuit diagram of an analog multiplying circuit according to a fourth embodiment mode of the present invention.
[0025] [0025]FIG. 8 is a circuit diagram of a variable gain amplifying circuit according to the fourth embodiment mode of the present invention.
[0026] [0026]FIG. 9 is a circuit diagram of the conventional analog multiplying circuit.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] Referring now to FIG. 1 to FIG. 8, various embodiment modes of the present invention will be described in detail.
First Embodiment Mode
[0028] A first embodiment mode of the present invention is an analog multiplying circuit in which while an input circuit arranged by a current mirror circuit is provided in the Gilbert cell type multiplying circuit, a total number of longitudinally-stacked stages of transistors is selected to be 2 stages.
[0029] [0029]FIG. 1 is a circuit diagram for representing an arrangement of an analog multiplying circuit according to a first embodiment mode of the present invention. It should be noted that the same reference numerals used in the prior art will be employed as those for denoting the same operations/functions of this analog multiplying circuit. In FIG. 1, a first analog differential signal V 1 p and a first analog differential signal V 1 n are applied to bases of two sets of differential pairs Q 1 -Q 2 and Q 3 -Q 4 arranged by employing transistors Q 1 to Q 4 . A collector of the transistor Q 1 is connected to a collector of the transistor Q 3 so as to form an output terminal V 0 p, and a collector of the transistor Q 2 is connected to a collector of the transistor Q 4 so as to form an output terminal Von. Also, these collectors are connected via load resistors R 1 and R 2 to a power supply voltage Vcc. To an emitter of the differential pair Q 1 -Q 2 and an emitter of the differential pair Q 3 -Q 4 , collectors of transistors Q 5 and Q 6 are connected, respectively.
[0030] Emitters of the transistors Q 11 and Q 12 are connected via a resistor R 11 and another resistor R 13 to the ground, respectively. Bases of the transistors Q 11 and Q 12 are connected to an input circuit 101 and another input circuit 102 , respectively. The input circuit 101 and the input circuit 102 are arranged by current sources Ics 1 and Ics 2 ; transistors Q 12 and Q 14 ; and resistors R 12 and R 14 . It is so assumed that a current of the current source Ics 1 , or the current source Ics 2 is selected to be “Ics.” Both emitters of the transistors Q 12 and Q 14 form an input terminal V 1 p and another input terminal V 1 n, and are connected via a resistor R 12 and another resistor R 14 to the ground. Also, both the transistor Q 12 and the transistor Q 11 constitute a current mirror circuit, and both the transistor Q 13 and the transistor Q 14 constitute a current mirror circuit. These transistors Q 12 /Q 11 /Q 13 /Q 14 own such a function that biases of both the transistor Q 11 and the transistor Q 13 are set so as to transfer input signals.
[0031] Referring now to FIG. 1, operations of the analog multiplying circuit with employment of the above-described circuit arrangement, according to the first embodiment mode of the present invention, will be described. A first description will now be made of operations of both the input circuit 101 and the input circuit 102 . The input circuit 101 and the input circuit 102 are constituted by the current mirror circuit made of both the transistor Q 11 and the transistor Q 12 , and also by the current mirror circuit made of both the transistor Q 13 and the transistor Q 14 . These current mirror circuits sets bias currents of the transistors Q 11 and Q 13 .
[0032] In the case that no input signal is supplied to the input terminals V 1 p and V 1 n, assuming now that current amplifications “hfe” of transistors are very large, a relationship among the current Ics flowing through the transistors Q 11 and Q 13 , a bias current I 13 of the transistor Q 11 , and a bias current I 14 of the transistor Q 14 may be expressed by the following formulae (6) and (7):
Ics *R 12 + Vt* 1 n (Ics/Is)=I 13 *R 11 + Vt* 1 n (I 13 / Is ) (6)
Ics *R 14 + Vt* 1 n (Ics/Is)=I 14 *R 13 + Vt* 1 n (I 14 / Is ) (7)
[0033] Also, when a signal is entered to both the input terminal V 1 p and the input terminal V 1 n, since collector currents flowing through the transistors Q 12 and Q 14 are determined by the current source Ics, both the transistor Q 12 and the transistor Q 14 may function as buffers. At this time, an input impedance of the input terminal V 2 p becomes a parallel impedance between a dynamic resistor re 12 of the transistor Q 12 and the resistor R 12 , and an input impedance of the input terminal V 2 n becomes a parallel impedance between a dynamic resistor re 14 of the transistor Q 14 and the resistor R 14 . As a consequence, the bias currents of the transistor Q 11 and the transistor Q 13 may be set by this input circuit. Furthermore, both the input impedance of the input terminal V 2 p and the input impedance of the input terminal V 2 n may be determined by this input circuit.
[0034] Next, both an output current I 13 of the transistor Q 11 and an output current I 14 of the transistor Q 13 are calculated which constitute a differential amplifier connected to both the input circuit 101 and the input circuit 102 . Assuming now that a base-to-emitter voltage of the transistor Q 11 is Vbe 11 and a base-to-emitter voltage of the transistor Q 13 is Vbe 13 , both an output current I 13 of the transistor Q 11 and an output current I 14 of the transistor Q 13 , which constitute another differential amplifier, may be expressed by the following formulae (8) and (9):
I 13 ={V 2 p+ Vt* 1 n ( Ics /I 13 )}/R 11 (8)
I 14 ={V 2 n+ Vt* 1 n ( Ics /I 14 )}/R 13 (9)
[0035] As a consequence, in such a case that the resistance values are set to R 11 =R 13 , an output current 2*ΔI=I 13 -I 14 of the first differential amplifier may be expressed by the following formula (10):
2*ΔI=I 13 -I 14 ={(V 2 p−V 2 n)+ Vt* 1 n (I 14 /I 13 )}/R 11 (10)
[0036] Similar to the prior art, this differential current is entered into the differential circuits made of the transistors Q 1 -Q 2 and of the transistors Q 3 -Q 4 . As a consequence, while the base currents are neglected, a differential current “I 11 -I 12 ” outputted from the load resistors R 1 and R 2 may be expressed by the below-mentioned formula (11):
I 11 -I 12 =2*ΔI*tan h {(V 1 p−V 1 n)/2 Vt }={(V 2 p−V 2 n)+ Vt* 1 n (I 14 /I 13 )}/R 11 *tan h {(V 1 p−V 1 n)/2Vt} (11)
[0037] Furthermore, when V 1 p−V 1 n<<Vt, the following equation may be satisfied:
tan h {(V 1 p−V 1 n)/2 Vt }=(V 1 p−V 1 n)/2 Vt
[0038] Then, a multiplication is carried out between two signals, as indicated in the following formula (12):
I 11 -I 12 ={(V 2 p−V 2 n)+ Vt* 1 n (I 14 /I 13 )}/R 11 *{(V 1 p−V 1 n)/2 Vt} (12)
[0039] As previously described, a multiplied output between the two analog signals may be obtained. Since a total number of longitudinally-stacked stages of the transistors are two stages, in the case that silicon bipolar transistors are used, even when base-to-emitter voltages of the silicon bipolar transistors and amplitude voltage portions of input/output signals are secured, this analog multiplying circuit can be operated under the power supply voltage Vcc=2.0 V.
[0040] Also, in order to suppress the adverse influence caused by the non-linear characteristics of both the transistor Q 11 and the transistor Q 13 , even in such a case that the collector currents of both the transistors Q 11 and Q 13 are increased, the collector currents may be arbitrarily set based upon the current sources Ics 1 , Ics 2 of the input circuits 101 , 102 , and the resistors R 12 and R 14 .
[0041] It should be understood that the current consumption of the analog multiplying circuit according to this embodiment mode is merely increased by the currents of both the current sources Ics 1 and Ics 2 , as compared with that of the prior art. Since the current values of the current sources may be freely set by changing the resistors R 12 and R 14 , the increases of the current consumption can be suppressed.
[0042] Also, as shown in FIG. 2, while both the collector of the transistor Q 2 and the collector of the transistor Q 3 are connected to the power supply voltages, since the gain is controlled based upon a voltage difference between the input signal V 1 p and the input signal V 1 n, such a variable gain amplifying circuit may be arranged by which both the input signal V 2 p and the input signal V 2 n can be amplified by a desirable gain. Also, in this case, a similar effect achieved by the above-described analog multiplying circuit may be achieved by this variable gain amplifying circuit.
[0043] As previously explained, in accordance with the first embodiment mode of the present invention, while the input circuits constituted by the current mirror circuits are employed in the Gilbert cell type analog multiplying circuit, the longitudinally-stacked stages of the transistors are realized by two stages. As a consequence, the minimum power supply voltage can be selected to be 2.0 V.
Second Embodiment Mode
[0044] A second embodiment mode of the present invention corresponds to such an analog multiplying circuit featured by that a base current compensating circuit is provided in an input circuit made of a current mirror circuit arrangement as to a Gilbert cell type analog multiplying circuit in which a longitudinally-stacked stage of transistors is selected to be 2 stages.
[0045] [0045]FIG. 3 is a circuit diagram for representing an arrangement of an analog multiplying circuit according to a second embodiment mode of the present invention. It should be noted that the same reference numerals shown in the conventional analog multiplying circuit will be employed as those for indicating the same operations/functions in the second analog multiplying circuit. In FIG. 3, a different structural point with respect to the first embodiment mode shown in FIG. 1 is given as follows: Both a transistor Q 15 and a transistor Q 16 are additionally employed in order to compensate for base currents flowing through the current mirror circuits of the input circuit 101 and the input circuit 102 . These current mirror circuits are arranged by the transistors Q 12 and Q 11 , and the transistors Q 13 and Q 14 .
[0046] Referring now to FIG. 3, operations of the analog multiplying circuit with employment of the above-explained arrangement, according to the second embodiment mode of the present invention, will now be explained. In the first embodiment mode, the distortion characteristic in the multiplying circuit is largely and adversely influenced by the non-linear characteristic of the transistors Q 11 and Q 13 . To suppress this adverse influence, both the collector current of the transistor Q 11 and the collector of the transistor Q 12 are required to be increased. In this case, an adverse influence of base currents of transistors cannot be neglected in the current mirror circuits of the input circuits 101 and 102 , which are constituted by the transistors Q 11 /Q 12 and the transistors Q 13 /Q 14 .
[0047] In the second embodiment mode of the present invention, the transistors Q 15 and Q 16 used to compensating for the base currents are inserted in order to reduce the adverse influence of the base currents of the current mirror circuits employed in the input circuits 101 and 102 of the first embodiment mode. As a consequence, the operations of the second embodiment mode are similar to those of the first embodiment mode, so that a similar function can be owned.
[0048] Similar to the second embodiment mode, as explained above, while the minimum power supply voltage Vcc(min) is selected to be 2.0 V, the multiplied output of the two analog signals can be obtained. Furthermore, in order to suppress the adverse influence of the non-linear characteristics of the transistors Q 11 and Q 13 , even in such a case that the collector current of the transistor Q 11 and the collector current of the transistor Q 13 are increased, the adverse influence caused by the base currents of the current mirror circuits can be reduced, and the distortion characteristic of the analog multiplying circuit can be improved.
[0049] Also, as shown in FIG. 4, while both the collector of the transistor Q 2 and the collector of the transistor Q 3 are connected to the power supply voltages, since the gain is controlled based upon a voltage difference between the input signal V 1 p and the input signal V 1 n, such a variable gain amplifying circuit may be arranged by which both the input signal V 2 p and the input signal V 2 n can be amplified by a desirable gain. Also, in this case, a similar effect achieved by the above-described analog multiplying circuit may be achieved by this variable gain amplifying circuit.
[0050] As previously described, in accordance with the second embodiment mode of the present invention, since the analog multiplying circuit is arranged in such a manner that the base current compensating circuit is employed in the input circuit made of the current mirror circuit arrangement with respect to the Gilbert cell type analog multiplying circuit in which the longitudinally-stacked stage of the transistors is made by the two stages, the distortion characteristic can be improved while suppressing the adverse influences of the non-linear characteristic. While the minimum power supply voltage Vcc(min) is selected to be 2.0 V, the multiplied output between the two analog signals can be obtained.
Third Embodiment Mode
[0051] An analog multiplying circuit, according to a third embodiment mode of the present invention, is such a Gilbert cell type analog multiplying circuit featured by that a longitudinally-stacked stage of transistors is selected to be 2 stages, and an emitter resistor of a differential amplifying circuit is constituted by an inductance.
[0052] [0052]FIG. 5 is a circuit diagram for representing an arrangement of an analog multiplying circuit according to a third embodiment mode of the present invention. It should be noted that the same reference numerals shown in the conventional analog multiplying circuit will be employed as those for indicating the same operations/functions in the second analog multiplying circuit. In FIG. 5 , a different structural point with respect to the second embodiment mode shown in FIG. 3 is given as follows: That is, the resistor R 11 and the resistor R 13 , which are connected to the emitter of the transistor Q 11 and the emitter of the transistor Q 13 , are replaced by an inductor L 11 and another inductor L 13 , respectively.
[0053] Referring now to FIG. 5, operations of the analog multiplying circuit with employment of the above-explained arrangement, according to the third embodiment mode of the present invention, will now be explained. Both an input circuit 201 and an input circuit 202 are arranged in a similar manner to those of the second embodiment mode, and own similar functions and also similar performance. Output currents I 13 and I 14 of the transistors Q 11 and Q 13 which constitute the differential amplifiers in a high frequency range may be expressed based upon the following formulae (13) and (14), assuming and that an impedance of the inductor L 11 is “Z 11 ”, and an impedance of the inductor L 13 is “Z 13 .”
I 13 ={V 2 p+ Vt* 1 n (Ics/I 13 )}/Z 11 (13)
I 14 ={V 2 n+Vt*1 n ( Ics /I 14 )}/Z 13 (14)
[0054] As a consequence, in such a case that the impedance is selected to be Z 11 =Z 13 , an output current 2*ΔI=I 13 -I 14 of the first differential amplifier may be represented by the formula(15):
2*ΔI=I 13 −I 14 ={(V 2 p−V 2 n)+ Vt *1 n (I 14 /I 13 )}/Z 11 (15)
[0055] Similar to the prior art, this differential current is entered into the differential circuits made of the transistors Q 1 -Q 2 and of the transistors Q 3 -Q 4 . As a consequence, while the base currents are neglected, a differential current “I 11 -I 12 ” outputted from the load resistors R 1 and R 2 may be expressed by the below-mentioned formula (16):
I 11 −I 12 =2*ΔI*tan h {(V 1 p−V 1 n)/2 Vt}={ (V 2 p−V 2 n)+ Vt *1 n (I 14 /I 13 )}/Z 11 *tan h {(V 1 p−V 1 n)/2 Vt} (16)
[0056] Furthermore, when V 1 p−V 1 n<<Vt, the following equation may be satisfied:
tan h {(V 1 p−V 1 n)/2 Vt }=(V 1 p−V 1 n)/2 Vt
[0057] Then, a multiplication is carried out between two signals, as indicated in the following formula (17):
I 11 -I 12 ={(V 2 p−V 2 n) +Vt* 1 n (I 14 /I 13 )}/Z 11 *{(V 1 p−V 1 n)/2 Vt} (17)
[0058] As explained above, while a DC voltage drop by the inductor L 11 and L 13 is eliminated, and the power supply voltage is further lowered, the multiplied output between the two analog signals can be obtained.
[0059] Also, as shown in FIG. 6, while both the collector of the transistor Q 2 and the collector of the transistor Q 3 are connected to the power supply voltages, since the gain is controlled based upon a voltage difference between the input signal V 1 p and the input signal V 1 n, such a variable gain amplifying circuit may be arranged by which both the input signal V 2 p and the input signal V 2 n can be amplified by a desirable gain. Also, in this case, a similar effect achieved by the above-described analog multiplying circuit may be achieved by this variable gain amplifying circuit.
[0060] As previously described, in accordance with the third embodiment mode of the present invention, since the analog multiplying circuit is arranged in such a manner that the emitter resistance of the differential amplifying circuit is replaced by the inductance with respect to the Gilbert cell type analog multiplying circuit in which the longitudinally-stacked stage of the transistors is made by the two stages, while the minimum power supply voltage Vcc(min) is lowered rather than 2.0 V, the multiplied output between the two analog signals can be obtained.
Fourth Embodiment Mode
[0061] An analog multiplying circuit, according to a fourth embodiment mode of the present invention, is such a Gilbert cell type analog multiplying circuit featured by that a longitudinally-stacked stage of transistors is selected to be 2 stages, and a parallel resonant circuit is connected to an emitter of a transistor which constitutes a differential amplifying circuit.
[0062] [0062]FIG. 7 is a circuit diagram for representing an arrangement of an analog multiplying circuit according to a fourth embodiment mode of the present invention. It should be noted that the same reference numerals shown in the conventional analog multiplying circuit will be employed as those for indicating the same operations/functions in the fourth analog multiplying circuit. In FIG. 7, the analog multiplying circuit of this fourth embodiment mode owns a different technical point, as compared with that of the third embodiment mode shown in FIG. 5. That is, both a capacitor C 11 and another capacitor C 12 are connected parallel to both an inductor L 11 and another inductor L 13 , which are connected to the respective emitters of transistors Q 1 and Q 13 , constituting a differential amplifying circuit. Also, a resistor R 15 is inserted between the emitter of the transistor Q 11 and the emitter of the transistor Q 13 .
[0063] Referring now to FIG. 7, operations of the analog multiplying circuit with employment of the above-explained arrangement, according to the fourth embodiment mode of the present invention, will now be explained. Both an input circuit 201 and an input circuit 202 are arranged in a similar manner to those of the third embodiment mode, and own similar functions and also similar performance. Since a parallel resonant circuit constituted by the inductors L 11 /L 13 and the capacitors C 11 /C 12 is employed, an impedance may be made of an infinite value at a desirable frequency, whereas the impedance may become substantially zero at any frequencies other then this desirable frequency. These inductors L 11 /L 13 and capacitors C 11 /C 12 are connected to the emitters of the transistors Q 11 and Q 13 , which constitute the differential amplifiers connected to both the input circuit 201 and the input circuit 202 . As a result, bias currents of the analog multiplying circuit according to this fourth embodiment mode may be set in a similar manner to that of the third embodiment mode. Also, since the impedance may become the infinite value at such a desirable frequency, an output current of the differential amplifying circuit may be determined based upon the resistor R 15 connected between the emitters of the transistors Q 11 and Q 13 in a similar manner to the prior art. At this time, the output current is represented by the below-mentioned formula (18):
2*ΔI=I 13 −I 14 =2*{V 2 p−V 2 n+ Vt* 1 n (I 14 /I 13 )}/R 15 (18)
[0064] This formula (18) is established by merely replacing the resistor Re by the resistor R 15 in the output current of the differential amplifying circuit employed in the conventional analog multiplying circuit.
[0065] Also, similar to the conventional analog multiplying circuit, assuming now that a current flowing through the load resistor R 1 is “I 11 ”, a current flowing through the load resistor R 2 is “I 12 ”, and symbol “Vt” indicates a thermal voltage, a differential output current “I 11 -I 12 ” may be expressed by the following formula (19), while the base currents are neglected:
I 11 −I 12 =2*{(V 2 p−V 2 n)+ Vt* 1 n (I 14 /I 13 )}/R 15 *{(V 1 p−V 1 n)/2 Vt} (19)
[0066] As previously described, the multiplied output between the two analog signals can be obtained. In accordance with the analog multiplying circuit of the fourth embodiment mode, the impedances connected to the emitters of the transistors Q 1 and Q 13 can be neglected, as compared with the third embodiment mode. Also, since the differential output circuit of the transistors Q 11 and Q 13 is determined based upon the resistor R 15 , the linear characteristics linearity) of the transistors Q 11 and Q 13 can be improved.
[0067] Also, as shown in FIG. 8, while both the collector of the transistor Q 2 and the collector of the transistor Q 3 are connected to the power supply voltages, since the gain is controlled based upon a voltage difference between the input signal V 1 p and the input signal V 1 n, such a variable gain amplifying circuit may be arranged by which both the input signal V 2 p and the input signal V 2 n can be amplified by a desirable gain. Also, in this case, a similar effect achieved by the above-described analog multiplying circuit may be achieved by this variable gain amplifying circuit.
[0068] As previously explained, in accordance with the fourth embodiment mode of the present invention, in the Gilbert cell type analog multiplying circuit in which the longitudinally-stacked stages of the transistors are realized by two stages, the parallel resonant circuits are connected to the emitters of the transistors which constitute the differential amplifying circuits. As a result, the linearity can be improved.
[0069] Also, it should be noted that the bipolar transistors are employed in the embodiment modes of the present invention. Alternatively, if elements owns a similar function to that of such a bipolar transistor, then any other electronic devices such as FET and MOS transistor may be employed. Also, the circuit arrangements of the input circuits 101 , 102 , 201 , and 202 are merely exemplified. If any other circuits have a similar function, then these circuits may be equivalently used. Alternatively, while the analog multiplying circuits and the variable gain amplifying circuits according to the embodiment modes of the present invention are employed, a frequency converting apparatus, a communication terminal apparatus, and a base station apparatus may be arranged. Also, such a communication system with employment of a communication terminal apparatus and a base station apparatus may be constituted by employing the above-described analog multiplying circuits and variable gain amplifying circuit. Furthermore, since the analog multiplying circuits and the variable gain amplifying circuits can be operated under low power supply voltages, the resulting power consumption can be reduced.
[0070] As apparent from the foregoing descriptions, the analog multiplying circuit of the present invention is arranged by such an analog multiplying circuit comprising: a first differential pair constructed of a first transistor and a second transistor, the emitters of which are commonly connected to each other; a second differential pair constructed of a third transistor and a fourth transistor, the emitters of which are commonly connected to each other; a first input terminal connected to a commonly-connected base of the second transistor and the third transistor; a second input terminal connected to a commonly-connected base of the first transistor and the fourth transistor; a first output terminal connected to a commonly-connected collector of the first transistor and the third transistor; a second output terminal connected to a commonly-connected collector of the second transistor and the fourth transistor; a first resistor connected between the first output terminal and a power supply; a second resistor connected between the output terminal and the power supply; a fifth transistor, the collector of which is connected to the commonly-connected emitter of the first differential pair; a sixth transistor, the collector of which is connected to the commonly-connected emitter of the second differential pair; a third resistor connected between an emitter of the fifth transistor and the ground; a fourth resistor connected between an emitter of the sixth transistor and the ground; first input means connected to a base of the fifth transistor; and second input means connected to a base of the sixth transistor; wherein: the first input means is arranged by first current generating means, first current mirror means constituted by both the fifth transistor and a seventh transistor, a fifth resistor connected between an emitter of the seventh transistor and the ground, and a third input terminal connected to the emitter of the seventh transistor; and the second input means is arranged by second current generating means, second current mirror means constituted by both the sixth transistor and an eighth transistor, a sixth resistor connected between an emitter of the eighth transistor and the ground; and a fourth input terminal connected to the emitter of the eighth transistor. Since such a circuit arrangement is employed, the analog multiplying circuit can be operated under low power supply voltages. As a consequence, a total number of longitudinally-stacked stages of the transistors can be made of two stages. The following effects can be achieved. That is, even when both the base-to-emitter voltages of the transistors and the amplitude voltage portions of the input/output signals are secured, the minimum power supply voltage Vcc(min) in the case that the silicon bipolar transistors are used can be selected to be 2.0 V. Thus, the analog multiplying circuit can be operated under low power supply voltage.
[0071] Since the analog multiplying circuit is arranged by that a ninth transistor for compensating a base current is employed in the first current mirror means; and a tenth transistor for compensating a base current is employed in the second current mirror means, the following effects can be achieved. That is, even in such a case that the collector current of the transistor is increased in order to suppress the distortion characteristic of the multiplying circuit, the adverse influences caused by the base current of the current mirror circuit can be reduced.
[0072] Also, since the analog multiplying circuit is arranged by that the third resistor is replaced by a first inductor; and the fourth resistor is replaced by a second inductor, there is such an effect that the DC voltage drop caused by the resistor can be eliminated, and furthermore, the power supply voltage can be lowered.
[0073] Also, since the analog multiplying circuit is arranged by further comprised of: a second resistor connected between the emitter of the fifth transistor and the emitter of the sixth transistor; a first capacitor connected parallel to the first inductor; and a second capacitor connected parallel to the second inductor, there is such an effect that the linearly of this analog multiplying circuit can be improved. | A first analog differential signal V1p and a first analog differential signal V1n are applied to the respectively commonly-connected bases of two sets of differential pairs which are constructed of transistors Q1 to Q4. A commonly-connected collector of Q1 and Q4 is used as an output terminal V0p, whereas a commonly-connected collector of Q2 and Q3 is used as another output terminal V0n. Collectors of Q11 and Q12 are connected to the respective commonly-connected emitters of these differential pairs. Parallel resonant circuits are connected to the respective emitters of Q11 and Q12, and the emitter-to-emitter path is connected by R15. Input circuits 101 and 102 are connected to the respective bases of Q11 and Q12. A second analog differential signal V2p and a second analog differential signal V2n are inputted to these input circuits 101 and 102. The transistors Q12 and Q14 of the input circuits 101 and 102 constitute current mirror circuits in connection with Q11 and Q13. A total number of longitudinally-stacked stages of the transistors can be made of two stages, and also the analog multiplying circuit can be operated under low power supply voltage. | 6 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This applications claims the benefit of U.S. provisional application 61/568,982, filed on Dec. 9, 2011, the entirety of which is incorporated herein.
FIELD OF THE INVENTION
[0002] The present invention relates to antitoxic fibers and fabrics and methods for their manufacture, most particularly, to methods for molecular grafting of antitoxins to fibers and media formed therefrom. The invention also relates to products comprising the antitoxic fibers and fabrics so formed.
BACKGROUND OF THE INVENTION
[0003] Various methods for producing antimicrobials for use in both nonwoven and woven fabrics are known. However, improvements in the production of antitoxins or antimicrobials and in the products that incorporate them, so that they exhibit both low toxicity and high efficacy, are still needed.
[0004] A woven or nonwoven material can be loaded with antitoxin in different ways and at different points during or after processing of the material. For example, an antitoxic agent can be embedded in fibers of a nonwoven, incorporated into the interstitial spaces of a material, or glued or sprayed onto an outer layer of a fabric following production. The method of incorporation and the location of the antitoxic agent in the material may have important consequences in imparting the desired efficacy and toxicology to the material and resultant product.
[0005] In the case of nonwoven materials, for example, one method involves physically entrapping the active agent within the three-dimensional structure of the nonwoven material. The active agent must have the appropriate size to be entrapped within the matrix structure of the nonwoven web. For instance, U.S. Publication No. 2006/0144403 (the '403 publication), to Messier, describes several methods of physically entrapping an active agent such as an iodine demand disinfectant resin in a three-dimensional nonwoven matrix. The '403 publication is hereby incorporated by reference in its entirety. Another method involves making use of a meltblown system where the desired active agent is provided in a cloud at the location closest to the extrusion point of the fibers. The cloud of active agent envelops the extruded fibers exiting a spinneret. Upon cooling, the active agent becomes physically entrapped within the fibers on the collecting web.
[0006] In addition to physically entrapping the active agent, certain methods of incorporating the active agent or antitoxin directly into the fiber are known. Generally, the active agent is blended with the polymer prior to extrusion so that it is present throughout the polymer. Upon solidification of the polymer, the active agent is dispersed throughout the resultant fiber. The active agent may diffuse to the surface of the nonwoven, where it exerts its toxic effect on the microorganism/toxin. For example, the '403 publication describes a method in which polymer granules are placed in a hopper along with active agent in powder form, preferably an iodine/resin disinfectant, prior to extrusion. The two components are then heated, extruded and attenuated to form fibers having the active agent incorporated therein. The resulting fibers having the active agent embedded can be air laid, vacuum laid or water laid. Nonwoven materials generated from this process can be utilized in various applications.
[0007] Although methods described above produce efficacious materials, a significant loss of the antitoxic agent may be encountered during the various processing steps. In the meltblown procedure, for instance, it is found that the steps of heating and extrusion may result in sublimation or leeching of the antitoxic agent from the web. The same holds true for other downstream steps of the process. Co-owned Int'l. Pub. No. WO 2011/103578 to Messier, et al., entitled “Materials and Processes for Producing Antitoxic Fabrics” (the '578 publication), addresses these issues by providing methods of producing materials manufactured with higher concentrations of active antitoxic agent in the final product.
[0008] In particular, the '578 publication discloses various methods for producing an antitoxic material by introducing iodine into a nonwoven material at various multiple stages of production. In one embodiment, a nonwoven material is formed from polymer staple fibers with an iodinated resin embedded therein, and then subjected to immersion in a liquid or gas containing triiodide or triiodine prior to being dried. The additional post-processing immersion step was found to increase the amount of active antitoxic agent that can be incorporated into a fabric.
[0009] While the addition of an immersion step in the post-processing of the nonwoven was found to increase the amount of antitoxin in the product, and thus increase the measured kill performance, this additive step was also found to increase the amount of leaching and toxicity. In addition, the added immersion step increases the overall cost. Accordingly, a need still exists for a method of producing fibers and fabrics exhibiting increased antitoxin load capacity and efficacy over time combined with reduced levels of toxicity. Further reduction of the manufacturing cost resulting from wasted antitoxin in the manufacturing process is also desired.
SUMMARY
[0010] The present invention provides cost-effective and efficient manufacturing processes for manufacturing fibers and fabrics formed therefrom, particularly nonwovens, containing antitoxins. The resultant fabrics exhibit advantageous properties such as increased antitoxin load capacity and efficacy combined with reduced levels of toxicity. The invention also provides products comprising the inventive antitoxic fibers and fabrics, such as: wound dressings, gowns, surgical drapes, protective clothing, shoe covers, hair covers, air filters, privacy curtains, and wipes.
[0011] Although methods described above for entrapping antitoxic agents into the three-dimensional matrix or into the fibers of a nonwoven web produce efficacious materials, it is found that significant loss of the antitoxic agent may be encountered during processing. In the meltblown procedure, for instance, it is found that the steps of heating and extrusion may result in sublimation or leeching of the antitoxic agent from the web. The same holds true for other downstream steps of the process. The loss of antitoxic agent during the manufacturing process is costly. In addition, the unused antitoxins constitute undesirable hazardous waste materials that must be properly disposed of.
[0012] The present invention addresses the need for efficient and cost-effective production of highly efficacious antitoxic fibers and fabrics. In particular, the novel manufacturing process of the present invention significantly increases the amount of active antitoxic agent that can be loaded or incorporated into a fiber and fibrous media formed therefrom using a molecular grafting technique employed in a single manufacturing step. The resultant fibrous media exhibit both high efficacy and low toxicity. In addition, the manufacturing process is simplified and the amount of antitoxin lost during the process is advantageously reduced.
[0013] In one aspect, a process for producing an antitoxic nonwoven fabric includes: providing a fibrous media comprising a material having a melt flow index of less than 150 MFI; forming a concentrated stable antitoxin solution comprising triiodide; fully immersing said media in said antitoxin solution to form a wet media; processing the wet media through rollers, thereby forcing the iodine to penetrate the media; and drying the wet media and isolating the fabric therefrom.
[0014] The antitoxin solution may also comprise an active agent selected from the group consisting of iodine, bromine, chlorine and hydrogen peroxide.
[0015] In various aspects, a wound dressing, surgical drape, privacy curtain, facemask, gown, article of protective clothing, air filter, shoe covering, hair covering, medical tape, or wipe comprises antitoxic fabrics formed according to the process described above.
[0016] In a particular embodiment, an antimicrobial medical tape comprises a spunbond treated material with the antitoxin solution and, preferably, an adhesive liner.
[0017] The fibrous media can be formed from a 50/50 blend of polypropylene and synthetic cellulose acetate or alginate fibers.
[0018] Various aspects of a wound dressing of the present invention comprises a nonwoven formed from a 50/50 blend of polypropylene and synthetic cellulose acetate or alginate fibers having iodine molecularly grafted thereto from an immersion in a triiodide solution.
[0019] In other aspects of the present invention, a facemask, for example, a surgical mask, or a privacy curtain comprises a nonwoven spunbond media characterized by an MFI of 30-40 having iodine molecularly grafted thereto from an immersion in a triiodide solution.
[0020] In additional aspects, the media comprises polypropylene.
[0021] In yet other aspects, the fibrous media is a nonwoven spunbond characterized by an MFI of 30-40.
[0022] In further aspects, the triiodide solution has a concentration of at least 2000 ppm iodine, at least 2500, or at least 25,000 ppm iodine.
[0023] In additional aspects, a surgical mask or privacy curtain comprises the antitoxic fabric formed according to the processes of the present disclosure, wherein the fibrous media comprises polypropylene, preferably a nonwoven, and wherein the antitoxin solution has a concentration of at least 2500 ppm iodine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a representative flow diagram of a testing method for testing swatches of various antimicrobial media formed in accordance with the present disclosure.
[0025] FIG. 2 is a table of results from the method of FIG. 1 for an embodiment of a facemask of the present disclosure.
[0026] FIGS. 1-8 describe the results of bacterial challenges on a nonwoven layer, suitable for an outer layer of a facemask, formed by the molecular grafting method of the present disclosure.
[0027] FIGS. 9-13 describe the results of bacterial challenges on a nonwoven layer, suitable for a curtain, formed in accordance with the molecular grafting method of the present disclosure.
DETAILED DESCRIPTION OF EMBODIMENTS
[0028] The following sections describe exemplary embodiments of the present invention. It should be apparent to those skilled in the art that the described embodiments of the present invention provided herein are illustrative only and not limiting, having been presented by way of example only. All features disclosed in this description may be replaced by alternative features serving the same or similar purpose, unless expressly stated otherwise. Therefore, numerous other embodiments of the modifications thereof are contemplated as falling within the scope of the present invention as defined herein and equivalents thereto.
[0029] Throughout the description, where items are described as having, including, or comprising one or more specific components, or where processes and methods are described as having, including, or comprising one or more specific steps, it is contemplated that, additionally, there are items of the present invention that consist essentially of, or consist of, the one or more recited components, and that there are processes and methods according to the present invention that consist essentially of, or consist of, the one or more recited processing steps.
[0030] It should be understood that the order of steps or order for performing certain actions is immaterial, as long as the invention remains operable. Moreover, two or more steps or actions may be conducted simultaneously.
[0031] Scale-up and/or scale-down of systems, processes, units, and/or methods disclosed herein may be performed by those of skill in the relevant art. Processes described herein are configured for batch operation, continuous operation, or semi-continuous operation.
[0032] It has been found and disclosed, for example, in co-owned U.S. application Ser. No. 12/381,328, the contents of which are incorporated herein by reference, that when iodinated resin is embedded in a fiber, the amount of iodine released into the environment is substantially less than the amount of iodine released when the iodinated resin is in “free” powder form, and hence not associated with a fiber, as, for example, when physically adhered or glued to a substrate. Moreover, filter media comprising fibers with embedded iodinated resin leach negligible amounts of iodide and are thus not toxic. The '578 publication discloses that the amount of active antitoxic agent incorporated into a material formed from fibers embedded with iodinated resin could be further increased by adding a post-processing immersion step in the manufacturing process. However, the amount of leaching in the final product was found to increase compared to the non-woven prepared without the post-processing immersion step. Moreover, the extra immersion step increases the overall manufacturing cost.
[0033] In the method of the present invention, an antitoxin is molecularly grafted to fibers and media formed therefrom in high concentrations through immersion of the media in a concentrated antitoxin solution. The resultant fabrics formed therefrom exhibit both superior efficacy and negligible toxicity. Moreover, the manufacturing process of the invention is drastically simplified and less costly compared to known methods of manufacturing antitoxic materials.
[0034] In a preferred embodiment, the antitoxin solution is a triiodide solution.
[0035] As used herein, triiodide refers to the triiodide ion, I 3 − , a polyatomic anion composed of three iodine atoms.
[0036] The following examples, while limited to the molecular grafting of iodine from triiodide solution, are not intended to necessarily limit the application of the invention to any one antitoxin. Additional antitoxins contemplated for use in the present invention in place of, or in addition to, iodine include, but are not limited to, bromine, chlorine, fluorine and hydrogen peroxide.
[0037] In alternative embodiments, the antitoxin solution for immersion of the fibrous media additionally comprises one of ethanol, 1-propanol, 2-propanol, isopropanol, cationic surfactant (e.g., benzalkonium chloride, chlorhexidine, octenidine dihydrochloride), metals, a quaternary ammonium compound (e.g., benzalkonium chloride (BAC), cetyl trimethylammonium bromide (CTMB), cetylpyridinium chloride (Cetrim, CPC), benzethonium chloride (BZT), chlorhexidine, octenidine), boric acid, brilliant green, chlorhexidine gluconate, mercurochrome, manuka honey, octenidine dihydrochloride, phenol (carbolic acid), sodium chloride, sodium hypochlorite, calcium hypochlorite, terpenes, or poly-hexa-methyl-biguanide (PHMB) or mixtures thereof. These active agents can be added alone or in combination with iodine molecule depending on the desired performance of the fabric produced.
[0038] The fibers and fibrous media of the present invention can include any material, which when treated with an antitoxin in accordance with the present invention, can be defined as non-leachable; e.g., a fibrous media formed therefrom exhibits no zone of inhibition, in accordance with the ASTM standard, designated E2149-01.
[0039] The fibers and fibrous media prepared for immersion in the concentrated antitoxin solution in accordance with the present invention are also preferably free from hydrophobic coverings or coatings. In contrast, scrims used in some facemasks tend to be made from polypropylene fibers that are compounded with a wax that is hydrophobic in order to impart splash resistant qualities. Such media will not efficiently absorb triiodide and are not preferred for forming the antitoxic media of the present invention.
[0040] It has been discovered that certain types of fibers can absorb a triiodide solution, formed as described below, and obtain a high concentration of iodine in the fiber, while exhibiting negligible or immeasurable leaching.
[0041] For example, a preferred material for forming the fibrous media is polypropylene. Other materials contemplated for use in the present invention include polyethylene, polyamide, nylon, PVC, and EMAC amongst others.
[0042] In one embodiment, an antitoxic nonwoven is formed by dipping the media in triiodide solution, wherein the nonwoven media comprises spunbond polypropylene fibers. The polypropylene media was found to be effective in absorbing the triiodide solution, as well as in releasing the active iodine agent in the presence of microorganisms. Products incorporating this antitoxic nonwoven, particularly, privacy curtains and facemasks, can be formed in accordance with the present invention.
[0043] Another preferred fiber for use in the present invention is synthetic cellulose acetate.
[0044] Yet another preferred fiber for use in the present invention is alginate.
[0045] In various embodiments, a nonwoven media is formed from a blend of polypropylene and either synthetic cellulose acetate or alginate, then dipped in triiodide solution to form an antitoxic nonwoven according to the present invention. The media was found to be effective in absorbing the triiodide solution, as well as in releasing the active iodine agent in the presence of microorganisms.
[0046] A particularly preferred antitoxic nonwoven media is formed from a 50/50 blend of (spunbond) polypropylene and synthetic cellulose acetate fibers dipped in triiodide solution. Another particularly preferred antitoxic nonwoven media is formed from a 50/50 blend of (spunbond) polypropylene and alginate fibers dipped in triiodide solution. Products, particularly wound dressings and antimicrobial tape, incorporating this antitoxic nonwoven are within the scope of this invention. Such wound dressings exhibit superior qualities over known dressings such as Silver-based dressings as well as other iodine dressings formed by other means.
[0047] Surprisingly, it was discovered that when synthetic cellulose acetate or alginate was substituted with rayon or natural cellulose, the triiodide was absorbed in minimal amounts, and was absorbed preferentially and primarily by the polypropylene. Therefore, the blends comprising rayon or natural cellulose fibers exhibit no or negligible kill capability and are, therefore, not preferred for use with the immersion technique described herein.
[0048] It was also surprisingly found that the capacity of fibers and fibrous media to absorb the antitoxin in concentrated solution, and to release the active agent upon contact with various microorganisms, differs depending on whether the media are formed from a meltblown process, or from a spunbond process.
[0049] Preferred media for immersion in concentrated antitoxin solution in accordance with the inventive methods are spunbond media (that are devoid of hydrophobic coverings or coatings). Spunbond media have been found to efficiently absorb triiodide solution, to release active iodine upon contact with microorganisms, and are defined to be non-leachable as determined by the ASTM E2149-01 standard. Accordingly, when prepared according to the method of the present invention, spunbond polypropylene fibers of 30 gsm, for example, exhibit superior kill performance over a long period of time.
[0050] In contrast, while meltblown fibers made from polypropylene of 30 gsm exhibited triiodide absorption when the meltblown media was immersed in triiodide solution, the fibers did not release active iodine and, therefore, did not exhibit the ability to kill or deactivate various microorganisms.
[0051] It was noted by the inventors that the tested polypropylene meltblown fibers are characterized by a melt flow index (MFI) of at least 150, while the spunbond fibers of polypropylene are characterized by a low melt flow index (MFI) of about 34 MFI. While not wishing to be bound by any particular theory, it is hypothesized that the lower (of about 34 MFI) MFI fibers work well because they also have a large Molecular Weight (MW), which helps take up the iodine as well as stabilize it in the fiber. Conversely, higher MFI fibers are characterized by a low Molecular Weight that may inhibit efficient take up and stabilization of iodine, and may promote the transformation of active iodine to iodide, which is inactive and ineffective to kill micro organisms.
[0052] Accordingly, in one embodiment, fibers and media formed therefrom of the present invention are characterized by a melt flow index (MFI) of at least 5 MFI. In another embodiment, the MFI is no more than 200 MFI, preferably 150 MFI. In yet another embodiment, the fibers are characterized by a melt flow index (MFI) of between about 50 and about 150 MFI. In still another embodiment, the fibers are characterized by a melt flow index (MFI) of between about 5 and about 50 MFI.
[0053] The method of the present invention includes immersion of the selected fibrous media described above in a triiodide solution characterized by a high concentration of solid iodine, preferably of at least 1000 ppm. By itself, the addition of iodine to an aqueous solution can result in a maximum of only about 330 ppm. Because a higher concentration is desired to maximize the loading of the antimicrobial in the fibers, potassium iodide is preferably added and mixed with the iodine in the water or other solvent to form the triiodide solution. The potassium iodide assists in converting the diatomic iodine to triiodide ions, resulting in concentrations over the approximately 330 ppm that can be achieved by adding solid iodine alone. Concentrations of up to 5000 ppm, and higher, close to saturation levels, are achieved by mixing iodine and potassium iodide to permit the iodine concentration to rise to the desired levels.
[0054] For example, a concentrated solution of about 129,600 ppm of iodine is achieved by adding potassium iodide. This solution is then diluted to the desired optimal levels.
[0055] In one embodiment, a concentrated solution for immersion of the media of the present disclosure comprises between about 1500 and about 3500 ppm, or more preferably between about 2000 to about 3000 ppm, or to about 2500 ppm, for efficient molecular grafting of iodine to fibers. In various particular embodiments, curtain and face mask media are formed by immersion in a solution of between about 1500 and about 3500 ppm, or more preferably between about 2000 to about 3000 ppm, or to about 2500 ppm.
[0056] In another embodiment, a concentrated solution for immersion of the media of the present disclosure comprises between about 3500 to about 6500 ppm, or more preferably between about 4500 to about 5500 ppm, or to about 5000 ppm, for efficient molecular grafting of iodine to fibers. In various particular embodiments, wound dressing media are formed by immersion in a solution of between about 3500 to about 6500 ppm, or between about 4500 to about 5500 ppm, or to about 5000 ppm.
[0057] In yet another embodiment, a concentrated solution for immersion of the media of the present disclosure comprises at least 400 ppm, preferably at least about 2500 ppm.
[0058] In an additional embodiment, a concentrated solution for immersion of the media of the present disclosure comprises at least between about 1000 ppm to about 10,000, or preferably, between about 5,000 to 10,000 ppm.
[0059] In still another embodiment, a concentrated solution for immersion of the media of the present disclosure comprises at least 25000 ppm for molecular grafting of iodine to fibers.
[0060] In still another embodiment, a concentrated solution for immersion of the media of the present disclosure comprises between about 25000 and about 26000 ppm for molecular grafting of iodine to fibers.
[0061] An example of the preparation of the concentrated triiodine solution before dilution for treating the fibrous media of the present invention is provided in Example 1 below.
[0062] As one of skill in the art will appreciate, there are many different species of iodine. The inventors discovered that for the media formed in accordance with the methods of the present disclosure, at least I 2 , I 3 − , HOI, I − , and IO 3 − are formed on the media after immersion in the concentrated antitoxin solution in a proportion where the iodine active is in a majority versus the other species. To test the media, the molecularly grafted material was cut into swatches of 1″×1″ and added to a 10 ml test tube of water. The sample was vortexed for 30 seconds before being analyzed on a spectrophotometer for each of the above species with a specific method for each. In this way, the amount in ppm of each species present could be determined. The inventors also observed that when air is passed through the media over a period of time, of 8 hours, for example, the media color changes from yellow to a light yellow. It was determined that the color change occurs as the species equilibrium shifts away from the I 2 towards the iodate and others, as the active iodine is released. When air is no longer flowing through the media, the yellow color comes back and the shift towards I 2 and less of the non active species like iodate and iodide.
[0063] The immersion step can be performed by dipping or immersing the media in the antitoxin solution for a period of time sufficient to achieve the desired concentration. The time of immersion may be a few seconds up to a few minutes, depending on the material, the concentration of the antitoxin in solution, and the desired resultant concentration in the fabric. It will be clear to one of ordinary skill in the art that the desired concentration in the fibers can be obtained by either increasing the immersion time or the concentration of the antitoxin in solution, or with an optimal combination of these parameters, depending on manufacturing needs.
[0064] FIGS. 1-8 show the testing of a material that can be used as a layer in a facemask, or other products, formed in accordance with the present invention and results therefrom for various microorganisms. A standard AATCC test method was applied to test the facemask antimicrobial properties under different conditions.
[0065] A preferred embodiment of a facemask formed in accordance with the present disclosure includes at least one layer, preferably an outer layer, treated with triiodide solution in accordance with the molecular grafting methods described herein. The facemask also includes an inner layer for contacting the wearer's face. In a most preferred embodiment, the facemask also includes a middle filtration layer.
[0066] FIG. 1 describes a testing method 10 of various swatches of antimicrobial media formed in accordance with the present disclosure. The antimicrobial-treated swatch is exposed to a microbial suspension for 15 minutes 12 . The swatch is then placed in a neutralizing fluid to recover viable microorganisms (colonies) 14 , which are then counted and recorded as colony forming units (CFU), in accordance with AATCC Test Method 100-2004 (AATCC 100 standard) 16.
[0067] FIGS. 2-8 are tables of results of testing a media formed in accordance with the present disclosure, using the method 10 described in FIG. 1 . FIGS. 2-8 describe the percent reduction in CFU when a sample of a non-woven spunbond material formed of polypropylene with an MFI of 30-40 MFI, treated by an immersion in a triiodide solution of 2500 ppm iodine, is contacted with various bacteria. The media can be used as an outer layer, or scrim, of a facemask, for example.
[0068] The results of exposure to various microorganisms for different conditions are shown in FIG. 2-8 . For example, FIG. 2 shows the percentage reduction of P. Aeruginosa challenge on a standard surgical mask (12.0325%) vs. freshly treated facemask swatch (99.9989%). FIG. 3 compares the result for a freshly treated facemask swatch with one which has been aged at 50° C. for 47 days (2.0 yrs. at Room Temp.). As shown, the percentage reduction of P. Aeruginosa was 99.999613% so that there was no measurable degradation in performance. FIGS. 4-6 show similar outstanding results after 47 days for S. aureus MRSA, of E. faecalis VRE, and K. pneumoniae challenges, respectively.
[0069] FIG. 7 describes AATCC 100 test results, using the method 10 of FIG. 1 , after a simulated use test of 8 hours for both fresh samples and speed-aged for 54 days for various microorganisms. The samples were pre-conditioned using a simulated breathing machine designed to mimic the mechanics and physical conditions of human breathing, simulating airflows of 26 LPM that a mask would typically be subjected to when worn for its intended use for extended periods of time. Following the preconditioning, the bacterial challenges were administered. As demonstrated, long-term use (8 hours) under conditions of moderate physical activity has no impact on the efficacy of the antimicrobial outer scrim of the inventive facemask, even after these devices have been subjected to speed-aging at 50° C.
[0070] In addition, the facemask antimicrobial-treated scrims were tested for toxicity. The values for conversion to total iodine intake are based on a sum of the iodine released from the mask, measured every fifteen minutes for a total of 8 hours, assuming a breathing rate of 1.6 m 3 /hr. As shown in FIG. 8 , iodine exposure levels were more than 1000 times lower than the set TLV (Threshold Limit Value) of 1.036 mg/m 3 . The iodine measurement test method was based on the OSHA ID-212 standard protocol. In addition, Iodine exposure levels were found to be approximately 100 times lower than the set TUIL (Tolerable Upper Intake level) of 1100 mg per day.
[0071] These tests showed that the treatment of the outer scrim of surgical masks with an iodine-based antimicrobial in accordance with the methods of the present invention provides a surgical facemask with strong antibacterial efficacy against Pseudomonas aeruginosa, Staphylococcus aureus MRSA, Klebsiella pneumoniae , and E. faecalis VRE after an exposure time of 15 minutes. Furthermore, stability testing performed under speed aging conditions indicated that the antimicrobial efficacy of the treated scrim material is maintained over time, even after an 8-hour usage period. Finally, the iodine immersion treatment raises no safety concerns in terms of exposure to ingested or inhaled iodine.
[0072] In one embodiment, a privacy curtain, preferably a disposable curtain, suitable for replacement preferably every six months includes an antitoxic layer formed in accordance with the present disclosure. For example, the antitoxic layer can be a non-woven spunbond material formed of polypropylene with an MFI of 30-40 MFI, which was immersed in a triiodide solution of about 2500 ppm iodine.
[0073] FIGS. 9-12 show the results of the same testing as done for FIGS. 3-6 for a non-woven spunbond material formed of polypropylene with an MFI of 30-40 MFI, treated by an immersion in a triiodide solution of 2500 ppm iodine, where the material can form a layer of a privacy curtain, or any other product of the present disclosure.
[0074] FIG. 13 is a table of results of testing a privacy curtain formed in accordance with the present disclosure using the ASTME 2149 testing method.
[0075] As described and shown in FIGS. 9-13 , the treatment of hospital curtain fabrics with the molecular grafted triiodide method of the present invention resulted in strong antibacterial efficacy against Pseudomonas aeruginosa, Staphylococcus aureus MRSA, Klebsiella pneumoniae , and E. faecalis VRE after an exposure time of 15 minutes. Furthermore, stability testing performed under speed aging conditions indicated that the antimicrobial efficacy of the treated curtain material is maintained over time.
[0076] FIG. 13 shows antimicrobial efficacy of the treated curtain as demonstrated by an alternative test method (ASTM E2149) with below detection levels of bacterial ( S. aureus, S. aureus MRSA, E. coli and A. baumannii ) and yeast ( C. albicans ) challenges recovered within contact times as short as 5 minutes, under speed aging conditions representative of 76 days.
[0077] Furthermore, testing has shown that the curtain fabrics treated with antitoxin solution in accordance with the molecular grafted triiodide method of the present invention showed no potential cytotoxic effects when tested in vitro, in accordance with 15010993-5 guidelines. In particular, an in vitro study was conducted to evaluate the antimicrobial curtain fabrics for potential cytotoxicity effects following the ISO 10993 guidelines. The treated curtain fabric was extracted in 1×MEM (Minimum Essential Medium) at 37° C. for 24 hours. The extract was then placed in contact with monolayers of fibroblasts and incubated for 48 hours. Monolayers were then examined for abnormal cell morphology and cellular degeneration. Extracts from the curtain fabric were tested and found to cause no evidence of cell lysis or toxicity (Grade 0). Accordingly, the curtain fabrics prepared in accordance with the present invention met the level of less than a Grade 2 required to meet the ISO 10993 guidelines.
[0078] In a particular embodiment, an antimicrobial medical tape of the present disclosure includes a layer of a spunbond media, for example, having a MFI of less than 150 MFI, treated in accordance with the present method by immersion in a concentrated antitoxin solution comprising triiodide. Preferably, the concentration of triiodide is at least 2000 ppm. In one embodiment, the media is a 50/50 blend of (spunbond) polypropylene and alginate or synthetic cellulose acetate fibers.
[0079] The medical tape preferably also includes an adhesive liner.
[0080] The invention provides a novel method of making fibrous media or fabrics with antitoxic (e.g., biocidal) properties. The fabrics can be either wovens or nonwovens. The antitoxic properties are imparted to the fabric by introducing an active agent, particularly an antimicrobial agent, to the fabric by immersion in a concentrated antitoxic solution. The fabrics produced in accordance with the present invention have widespread utility. For instance, they can be used as wound dressings, antimicrobial medical tape, gowns, drapes, air filters, protective clothing, shoe coverings, hair coverings, privacy curtains, facemasks, and wipes.
Example 1
Preparation of Triiodide Solution
[0081] A. Prepare 1N iodine (129,600 ppm I 2 ):
1. In a 1 L volumetric flask, add approx 250 mL high purity water 2. Weigh out 175 g of KI solid and add to the 1 L flask containing the water 3. Swirl solution in flask to dissolve all KI. 4. Weigh out 130 g of Iodine solid and add to the 1 L flask containing the KI and water solution 5. Fill the volumetric flask with high purity water to the marked line 6. Add a magnetic stir bar to the flask 7. Cap the flask with a glass stopper 8. Cut a piece of parafilm and wrap it around the top of the flask/stopper to prevent any leakage 9. Take the flask and place it on a magnetic stir plate. 10. Set stir control to 7 and let the solution mix overnight to dissolve all iodine solid 11. Dilute according to needs
[0093] It should be apparent to those skilled in the art that the described embodiments of the present invention provided herein are illustrative only and not limiting, having been presented by way of example only. As described herein, all features disclosed in this description may be replaced by alternative features serving the same or similar purpose, unless expressly stated otherwise. Therefore, numerous other embodiments of the modifications thereof are contemplated as falling within the scope of the present invention as defined herein and equivalents thereto. | The invention provides a novel method for producing an antitoxic nonwoven fabric by molecularly grafting the antitoxic molecule thereto. The method comprises immersing a fibrous media comprising a material having a melt flow index of less than 150 MFI in a stable antitoxin solution comprising an antitoxin, preferably triiodide. The wet media is processed through rollers, thereby forcing the antitoxic molecule (e.g., iodine) to penetrate the media. The wet media is dried, and the fabric isolated therefrom. The invention further provides products incorporating the antitoxic media formed by this molecularly grafting method, including a wound dressing, surgical drape, privacy curtain, facemask, gown, article of protective clothing, shoe covering, hair covering, air filter, medical tape, and wipe. | 3 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to certain novel hydrazides and the use thereof as curing agents for epoxy resins.
2. Description of the Prior Art
Epoxy resins are widely employed as electric insulating materials, various moulded products, adhesives or coatings because they give valuable cured resins having excellent mechanical, electrical and chemical properties when cured with suitable curing agents, for example acid anhydride and amine curing agents. However, epoxy resin composition incorporating amine curing agents are cured rapidly at ordinary temperature and at elevated temperature, and hence they lack storage stability. Also, epoxy resin compositions incorporating acid anhydride curing agents are stable at ordinary temperature, but heating for a long period of time at elevated temperature is required for full curing. Usually, tertiary amines, quaternary ammonium compounds or organo metal complexes are further added to the composition for the purpose of accelerating curing rate. However, the addition of such cure accelerator impairs storage stability markedly.
So-called latent curing agents which are compatible with epoxy resins to form a composition which is stable at relatively low temperature and which is rapidly cured when heated to elevated temperature are eagerly desired. In the field of coating, particularly, curing agents are desired which give colorless and transparent cured epoxy resin, from the view of tone of color. Representative compounds which have been heretofore proposed as latent curing agents are dicyandiamide, dibasic acid hydrazide, boron trifluoride-amine adduct, guanamine and melamine. Among these compounds, dicyandiamide, dibasic acid hydrazide and quanamine are useful in formulating epoxy resin compositions having excellent storage stability, but full curing by means of these compounds could be achieved only by heating at higher temperature than 150° C. for a long time. Also, boron trifluoride-amine adduct is hard to treat owing to its high hygroscopic property, and it affects the physical properties of the cured resin adversely.
There has been heretofore known almost no latent epoxy curing agent which causes rapid curing at moderate elevated temperature (that is 100° C.-150° C.) and which gives an epoxy resin composition having excellent storage stability at ordinary temperature.
SUMMARY OF THE INVENTION
An object of the present invention is to provide novel hydrazide-type curing agents which are useful in making storable one-package curable epoxy resin compositions.
Another object of the present invention is to provide hydrazide-type curing agents which alone or together with other curing agents can activate a rapid curing of epoxy resin composition at relatively low temperatures and yet be extraordinarily resistant to gelling at 40° C. for three or more weeks.
A further object of the present invention is to provide hydrazide-type curing agents which give cured epoxy resin having excellent transparency and water resistance.
The above objects of the present invention may be substantially achieved by providing as a curing agent a hydrazide compound having the following general formula (I): ##STR3## wherein X is an aromatic hydrocarbon residue of a dihydric phenol, ##STR4##
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The hydrazides which may be represented by the above general formula (I) may be readily prepared by reacting an adduct of 1 mole of aromatic diol represented by the general formula OH--X--OH wherein X has the meanings set forth above and 2 moles of alkyl acrylate having the general formula CH 2 ═CHCOOR wherein R is alkyl group, with hydrazine hydrate, said adduct of aromatic diol and bimolecular alkyl acrylate being represented by the following general formula (a) ##STR5## wherein X has the meanings set forth above and R is alkyl group having 1-4 carbon atoms.
Although the aromatic diol-bimolecular alkyl acrylate adduct may be directly prepared by the addition reaction between an aromatic diol and alkyl acrylate, it may also be prepared by the following two-step reaction. That is, 1 mole of aromatic diol is reacted with 2 moles of acrylonitrile to form an aromatic diol-bimolecular acrylonitrile adduct, which is then subjected to alcoholysis whereby the nitrile group in the adduct is converted into a carboalkoxy group, said aromatic diol-bimolecular acrylonitrile adduct being represented by the general formula (b)
NCCH.sub.2 CH.sub.2 --O--X--O--CH.sub.2 CH.sub.2 CN (b)
wherein X has the meanings set forth above.
Preferred specific examples of the aromatic diols are catechol, resorcinol, hydroquinone, bisphenol A and bisphenol F.
The preparation of the aromatic diol-bimolecular alkyl acrylate may be carried out by heating an aromatic diol and an alkyl acrylate in the presence of a basic catalyst such as potassium hydroxide in the absence or presence of solvents such as methanol and ethanol at reflux temperature for several hours, the amount of alkyl acrylate being at least 2 times the amount of the aromatic diol (mole basis).
The preparation of the aromatic diol-bimolecular alkyl acrylate adduct starting from an aromatic diol and acrylonitrile may be accomplished by the process wherein 1 mole of aromatic diol is reacted with at least 2 moles of acrylonitrile in the presence of a basic catalyst with or without solvent similarly with the reaction between aromatic diol and alkyl acrylate at reflux temperature for 15-20 hours or at 130°-140° C. for several hours in an autoclave to obtain an aromatic diol-bimolecular acrylonitrile adduct (b), which is then heated in a mixed solution of 5% aqueous alcohol and acid at reflux temperature for several hours, the respective amount of alcohol and acid being at least 2 times the amount of the adduct (mole basis).
The alkyl acrylate to be reacted with the aromatic diol is not particularly limited. Usually a lower alkyl ester of 1-4 carbon atoms is employed. Especially a, methyl ester is practical.
The alcohol which is employed for preparation of the aromatic diol-bimolecular alkyl acrylate adduct from the aromatic diol-bimolecular acrylonitrile adduct is not particularly limited, but methanol and ethanol are practical.
Suitable examples of basic catalysts which can be used in the reaction system are potassium hydroxide, sodium methoxide and benzyltrimethylammonium hydroxide. The amount of basic catalyst may be about 1-2 percent by weight based on the aromatic diol. The addition reaction is carried out in the presence of a polymerization inhibitor such as hydroquinone. After the addition reaction has been completed, excess acrylic ester and solvent if any are removed from the reaction mixture by distillation.
The aromatic diol-bimolecular acrylic ester adduct (a) obtained thusly is further reacted with hydrazine hydrate in the presence of a solvent such as methanol or ethanol at room temperature for several hours, the amount employed of hydrazine hydrate being at least 2 times (mole basis) the amount of the adduct (a). The reaction may be carried out at reflux temperature if necessary.
After the completion of the reaction, excess hydrated hydrazine and the solvent are removed from the reaction mixture by distillation, and the precipitated hydrazide is separated and recrystallized from a suitable solvent such as methanol, ethanol or water. The hydrazide of the present invention may be pulverized in fine particles.
The hitherto known dibasic acid hydrazides, such as adipic acid hydrazide, sebacic acid hydrazide, isophthalic acid hydrazide and the like, are high melting compound above 180° C., and the epoxy resin compositions incorporating such dibasic acid hydrazides is cured when heated to 150° C. or higher temperatures. Contrary thereto, the hydrazides of the present invention are relatively low melting compounds and provide, when incorporated into an epoxy resin, curable composition which are stable for periods of several weeks at 40° C. and which can thereafter be readily cured at temperatures of as low as about 120°-140° C. to give a colorless, transparent and tough cured product having excellent water resistance.
The required amount of curing agent is determined by the number of active hydrogen atoms in the curing agent employed and the number of epoxy groups in the epoxy resins. In general, 0.5-1.5, preferably 0.7-1.2, active hydrogen equivalent weight per epoxy equivalent weight is employed.
As epoxy resins which may be applied to the hydrazide curing agents of the present invention, various well-known ones having an average of more than 1 epoxy groups in the molecule may be employed. Representative epoxy resins are those based on glycidyl ethers of polyhydric phenols such as 2,2-bis(4-hydroxyphenyl)-propane (Bisphenol A), resorcinol, hydroquinone, pyrocatechol, saligenin, glycidyl ether of Bisphenol F and glycidyl ether of phenolformaldehyde resin.
If necessary, other curing agents, cure accelerators and fillers may be employed in combination with the curing agent of the present invention.
The following examples illustrate the preparation of the hydrazides of the present invention.
EXAMPLE 1 ##STR6##
25 g (0.227 mole) of catechol, 75 g (1.42 mole) of acrylonitrile, and 0.5 gof sodium methylate were mixed in a 300 ml three-necked flask equipped witha reflux condensor and a stirrer. The mixture was heated under reflux for 20 hours and the reaction mixture was dissolved in benzene. After washing three times with 100 ml of water, benzene and excess acrylonitrile were removed under reduced pressure to obtain the viscous liquid. To this compound, 50 ml of methanol was added, and the mixture was stirred to precipitate the crystals. After filtration, the crystals were washed with methanol and dried in vacuo to obtain 11.2 g of the bimolecular acrylonitrile adduct of catechol (I)-a". mp 120°˜122° C. ##STR7##
A mixture of 1% methanol solution and sulfuric acid (each 30 g) was added to 8 g (0.037 mole) of the adduct thus obtained and was heated under reflux for 7 hours with stirring. To this reaction mixture, 100 ml of water was added to dissolve the produced ammonium sulfate crystals. Then 300 ml of ethyl ether was added to extract the reactor. After washing the extract with 100 ml of 5% sodium hydroxide solution and three times with 100 ml of water, ethyl ether was removed under reduced pressure to obtain 4.6 g of the adduct of catechol and bimolecular methyl acrylate (I-a'). ##STR8##
4.5 g (0.028 mole) of the adduct thus obtained and 10 g (0.16 mole) of 80% hydrazine hydrate solution were mixed in a 100 ml three-necked flask equipped with a stirrer. To this mixture, 50 ml of methanol was added and then was allowed to react at 50° C. for 2 hours with stirring. After cooling, the precipitated crystals were filtered, washed with methanol, and dried in vacuo to obtain the target product as white needles.
The analytical values are shown below.
______________________________________Melting point 145˜146° C.Elemental analysis C H N (%)Found 51.27 6.42 19.71Calculated for C.sub.12 H.sub.18 O.sub.4 N.sub.4 51.06 6.38 19.86Field desorption mass spectrum [M + H].sup.+ at m/e 283______________________________________
EXAMPLE 2 ##STR9##
35 g (0.318 mole) of resorcinol, 350 ml (3.89 mole) of methyl acrylate, and0.7 g of potassium hydroxide were mixed in the same flask described in Example 1, and the mixture was heated under reflux for 7 hours with stirring. To the reaction mixture, 4.6 ml of 10% hydrochloric acid solution was added, and excess methyl acrylate was removed under reduced pressure. Then, 1000 ml of ethyl ether was added, and insoluble material (potassium chloride) was filtered out. The residue was washed with 100 ml of 10% sodium hydroxide solution and three times with 100 ml of water, andethyl ether was removed in vacuo to obtain 33.4 g of the adduct of resorcinol and bimolecular methyl acrylate (I-b', mp 74°˜76° C., white needles). ##STR10##
32.3 g (0.115 mole) of the adduct of resorcinol and bimolecular methyl acrylate thus obtained was dissolved in 600 ml of methanol. To this solution, 115 ml (1.84 mole) of 80% hydrazine hydrate solution was added and was allowed to react at 50° C. for 2 hours with stirring. From the reaction mixture, excess hydrazine hydrate and methanol was removed under reduced pressure. The residue was washed with methanol and dried in vacuo to obtain 26.1 g of the target product as white powder.
The analytical values are shown below.
______________________________________Melting point 143˜144° C.Elemental analysis C H N (%)Found 50.91 6.40 19.82Calculated for C.sub.12 H.sub.18 O.sub.4 N.sub.4 51.06 6.38 19.86Nuclear magnetic resonance spectrumδ(DMSOd.sub.6 /TMS) ##STR11##3.1˜3.6(4H, br, NH.sub.2, (X2))4.08(4H, t, J = 6Hz, OCH.sub.2 CH.sub.2, (X2))6.3˜6.5(3H, m, arom)8.9˜9.1(2H, br, NHNH.sub.2, (X2))Field desorption mass spectrum [M + H].sup.+ at m/e 283______________________________________
EXAMPLE 3 ##STR12##
According to the procedure described in Example 1, 25 g (0.227 mole) of hydroquinone, 75 g (1.42 mole) of acrylonitrile and 0.6 g of sodium methoxide were mixed and were allowed to react to obtain 35.5 g of the bimolecular acrylonitrile adduct of hydroquinone (I-c"). ##STR13##
To 25 g (0.153 mole) of the adduct thus obtained, a mixture of 5% methanol solution and sulfuric acid (each 70 g) was added. Thereafter, the procedure of Example 1 was repeated to obtain 28.0 g of the adduct of hydroquinone and bimolecular methyl acrylate (I-c'). ##STR14##
18.0 g (0.063 mole) of the adduct of hydroquinone and methyl acrylate thus obtained were dissolved in 180 ml of methanol, and then 32 g (0.512 mole) of 80% hydrazine hydrate solution were added. The mixture was allowed to react according to the procedure described in Example 1. 16.5 g of the target product were obtained.
The analytical values are shown below.
______________________________________Melting point 173˜175° C.Elemental analysis C H N (%)Found 51.33 6.48 19.63Calculated for C.sub.12 H.sub.18 N.sub.4 O.sub.4 51.06 6.38 19.86Field desorption mass spectrum [M + H].sup.+ at m/e 283______________________________________
EXAMPLE 4 ##STR15##
40 g (0.175 mole) of bisphenol A, 315 ml (3.5 mole) of methyl acrylate, and6.5 ml of 10% benzyltrimethylammonium hydroxide solution were mixed in the same flask described in Example 1, and the mixture was heated under refluxfor 48 hours with stirring. After cooling to room temperature, 7.3 ml of 10% hydrochloric acid solution was added, and then excess methyl acrylate was removed in vacuo. The residue was dissolved in 1000 ml of ethyl acetate and washed successively with 200 ml of 10% hydrochloric acid solution, pure water, 10% sodium hydroxide solution, and twice with saturated sodium chloride solution. Then ethyl acetate was removed to obtain 27.7 g of the colorless oily substance. The oily substance thus obtained was purified by silica gel column chromatography using a mixture of toluene-acetic acid as an eluent to obtain 10.6 g of the bimolecular methyl acrylate adduct of bisphenol A (I-d'). ##STR16##
10.0 g (0.025 mole) of the adduct thus obtained, 100 ml of methanol, and 16ml (0.25 mole) of 80% hydrazine hydrate solution were mixed and allowed to react at room temperature for 5 hours with stirring. From the reaction mixture, excess hydrazine hydrate and methanol were removed under the reduced pressure, and then 50 ml of ethanol was added to the residue to precipitate the crystals. After filtration, the crystals were recrystallized from ethanol and dried in vacuo to obtain 8.26 g of the target product as a white powder.
The analytical values are shown below.
______________________________________Melting point 136˜140° C.Elemental analysis C H N (%)Found 62.75 6.91 14.11Calculated for C.sub.21 H.sub.28 N.sub.4 O.sub.4 62.98 7.05 13.99Nuclear magnetic resonance spectrumδ(DMSO-d.sub.6 /TMS)1.58(6H, s, CH.sub.3 --C--CH.sub.3)2.52(4H, t, J = 6Hz, --CH.sub.2 C--, (X2))4.17(4H, t, J = 6Hz, --OCH.sub.2 CH.sub.2 --, (X2))3.0 4.5(4H, br, --NHNH.sub.2, (X2))6.82(4H, d, J = 9Hz, arom)7.13(4H, d, J = 9Hz, arom)8.9 9.2(2H, br, --NHNH.sub.2, (X2))Field desorption mass spectrum [M + H].sup.+ at m/e 401______________________________________
EXAMPLE 5 ##STR17##
In an autoclave equipped with an electromagnetic stirrer, 40 g (0.2 mole) of bisphenol F, 27.6 g (0.52 mole) of acrylonitrile, and 0.5 g of sodium methylate were mixed. After nitrogen was substituted for air, the mixture was heated at 130°˜140° C. for 5 hours with stirring. After cooling, the reaction mixture was dissolved in 300 ml of benzene andwashed successively with 200 ml of 5% sodium hydroxide solution and 300 ml of water. Then the benzene layer was concentrated, and 100 ml of methanol was added to precipitate the crystals. After filtration, the crystals weredried in vacuo to obtain 6.04 g of the adduct of bisphenol F and bimolecular acrylonitrile (I-e"). mp 100°˜102° C. ##STR18##
The mixture of 5% methanol solution (30 g) and sulfuric acid (30 g) was added to 6.0 g (0.0237 mole) of the adduct thus obtained and heated under reflux for 5 hours with stirring, and then 300 ml of toluene was added. After being washed successively with 200 ml of water, 100 ml of 5% sodium hydroxide solution and 300 ml of water, the solution was concentrated and dried to obtain 5.65 g of white solid substance (I-e'). ##STR19##
5.65 g (0.015 mole) of the compound thus obtained was dissolved in 56 ml ofmethanol, and then 8.8 g (0.141 mole) of 80% hydrazine hydrate solution wasadded. The mixture was allowed to react at 50° C. for 2 hours with stirring. After filtration, the crystals were washed with methanol and dried in vacuo to obtain 4.16 g of the target product as white powder.
The analytical values are shown below.
______________________________________Melting point 182˜183° C.Elemental analysis C H N (%)Found 61.48 6.53 14.87Calculated for C.sub.19 H.sub.24 N.sub.4 O.sub.4 61.29 6.45 15.05Field desorption mass spectrum [M + H].sup.+ at m/e 373______________________________________
EXAMPLE 6
Reactivity, water resistance, and storage stability of the formulated epoxyresin were evaluated.
1. Preparation of the sample
The formulation of each sample is shown in Table 1. Each sample was stirredfor 1 hour with defoaming under reduced pressure by using a mixing and grinding machine.
2. Evaluation of the reactivity
(1) The sample was put into a gear oven for 60 minutes and cured temperature was measured.
(2) The sample was heated at 150° C. for 60 minutes and then at 60° C. for 180 minutes. The resulting cured resin was observed withthe naked eye.
3. Water resistance
1 g of the sample was put into a frame of 25 mm diameter and heated at 150° C. for 60 minutes and then at 160° C. for 180 minutes. The cured resin thus obtained was soaked in 50 cc of 40° C. hot water, and the weight change was measured.
4. Storage stability
The sample was put into a gear oven set to 40° C., and the day required for the sample becoming non-fluidity was measured.
TABLE 1______________________________________ Formulation No. 1 2 3 4 5 6 7 8______________________________________Epon 828*.sup.1 100 100 100 100 100 100 100 100Sample (I)-a 37Sample (I)-b 37Sample (I)-c 37Sample (I)-d 52Sample (I)-e 49Adipic 23dihydrideIsophtalic 26dihydrideDicyan- 28diamide______________________________________*.sup.1 A product of Shell Chemical Co. bisphenol A type epoxy resin havinepoxy equivalent of 175˜210.
TABLE 2______________________________________Cured temperatureFormulation No. Cured Temperature______________________________________No. 1 120° C.No. 2 120No. 3 140No. 4 120No. 5 140No. 6 160No. 7 160No. 8 180______________________________________
TABLE 3______________________________________Appearance of the cured resinFormulation No. Appearance______________________________________No. 1 Stiff and transparent materialNo. 2 Stiff and transparent materialNo. 3 Stiff and transparent materialNo. 4 Stiff and transparent materialNo. 5 Stiff and transparent materialNo. 6 Opaque white colored materialNo. 7 Opaque white colored gelNo. 8 Less transparent material______________________________________
TABLE 4______________________________________Water resistanceFormulation No. Water absorption______________________________________No. 1 + 1.8 wt %No. 2 1.7No. 3 1.5No. 4 1.6No. 5 1.8No. 6 2.9No. 7 1.8No. 8 --*.sup.1______________________________________*.sup.1 cannot be measured because the sample was not fullcured
TABLE 5______________________________________Storage stabilityFormulation No. Storage stability______________________________________No. 1 >4 weeksNo. 2 "No. 3 "No. 4 "No. 5 "No. 6 "No. 7 "No. 8 "______________________________________
The results of Table 2˜5 shows that the curing agent for epoxy resin in this invention has excellent storage stability, reactivity, and water resistance.
Especially, the reactivity of this agent is superior and the resulting cured resin is stiff and transparent compared with that of the control agent. | Hydrazides of the formula ##STR1## are good curing agents for epoxy resin, wherein in the formula, X is an aromatic hydrocarbon residue of dihydric phenol, ##STR2## The curing agents are useful in formulating novel storable one-package, heat-curable epoxy resin-based compositions. | 2 |
CROSS REFERENCE TO RELATED APPLICATION
The present application is a continuation application of U.S. application Ser. No. 13/584,096, filed Aug. 13, 2012, the contents of which are incorporated herein by reference in their entirety. U.S. application Ser. No. 13/584,096 is a continuation application of U.S. application Ser. No. 12/644,577, now U.S. Pat. No. 8,240,560, filed Dec. 22, 2009, the contents of which are also incorporated herein by reference in their entirety. U.S. application Ser. No. 12/644,577 is a continuation application of U.S. application Ser. No. 11/319,783, now U.S. Pat. No. 7,641,111, filed Dec. 29, 2005, the contents of which are also incorporated herein by reference in their entirety.
FIELD
The present invention relates generally to a method and apparatus for providing increased security for users of electronic equipment, such as, for example, mobile wireless communications devices, that include embedded circuits for enabling use with contactless payment systems. In particular, the disclosure is directed to methods and apparatus for providing authentication capability for devices that include contactless payment functionality.
BACKGROUND
Contactless payment systems are gaining widespread acceptance by retailers and are becoming increasingly popular among consumers. In contactless payment systems, also known as “Tap-and-Go” or “Pay and Wave” payment systems, consumers use a payment card or other device that is equipped with an integrated chip and antenna that securely communicates consumer account information via a radio frequency communication link to a retailer's payment terminal. The payment terminal then connects to an appropriate financial network or other back-end processing system via, for example, a communication network, to authorize the transaction. Once authorized, the consumer completes the transaction. This scheme of contactless payment accomplishes a transaction in a fraction of the time required by cash, traditional credit cards or debit card transactions, which require a card to be swiped through a reader.
Contactless payment devices typically include a chip and antenna. The chip includes, for example, consumer account information. When the chip is brought into close enough proximity to a suitable reader, the antenna will be activated and will transmit the consumer account information residing on the chip to the reader. Of course, to avoid errors and ensure that the reader is communicating with the correct device, the proximity of the contactless payment device to the reader required to activate the antenna is typically on the order of a very few inches at most.
The chip and antenna of known contactless payment systems may be incorporated into any of a number of form factors that are convenient for consumers. For example, these chips and antenna have been embedded into key fobs, contactless smart cards, and even cellular telephones. In the future, these chips and antenna may be incorporated into any of a variety of forms due to their small size. Because mobile wireless communications devices, such as, for example, cellular telephones, personal digital assistants, mobile e-mail devices, and the like, are being carried by more and more consumers, inclusion of the contactless payment system chips and antenna in these devices is becoming increasingly common.
However, such contactless payment systems suffer from a serious disadvantage that may result in unauthorized use of the device and significant loss of money or credit. For example, if a contactless payment device is lost, there is no quick and reliable way to avoid unauthorized use of the contactless payment device before the issuer of the account associated with the device is contacted by the user and the system cancels use of that particular device. In particular, there is no known solution for ensuring that the user of the contactless payment device is authorized to make payment using the contactless payment device. Of course, one solution may be to have the user enter a personal identification number or other like code at the point of sale to ensure that the user is authorized to make payment using the contactless device. This may be accomplished, for example, via a keypad associated with a contactless payment device reader. However, this solution may be somewhat at odds with the advantages associated with the use of such contactless payment systems in which speed and ease of use are paramount. Entering identifying information would slow the transaction speed down, and would not result in any more convenience than that associated with swiping a conventional credit or debit card to read its magnetic stripe.
Therefore, what is needed is a transparent way to authenticate a user of a contactless payment device that maintains the speed and convenience of contactless payment, while maintaining an acceptable level of security to ensure that unauthorized use of the device is restricted.
SUMMARY
In view of the foregoing, we have now identified an efficient, accurate and easy to implement system and method for authenticating contactless payments that is user friendly and transparent to the overall contactless payment system, yet maintains the convenience and transaction speed that make such contactless payment systems advantageous and desirable.
According to an exemplary embodiment, the contactless payment system chip may be integrated with the security system of the device into which it is integrated, such as, for example, a mobile wireless communications device. The mobile wireless communication device must have the ability to enable and/or disable use of the payment functionality of the contactless payment system chip. For example, the mobile wireless communication device may include password functionality that is typically used to enable use of the mobile wireless communications device for features other than contactless payment, such as, for example, locking the mobile wireless communication device keypad. If there is no password set for the mobile wireless communication device, then the payment functionality of the contactless payment chip is always enabled for use. However, if the password of the mobile electronic communication device is set, use of the payment functionality of the contactless payment chip may be disabled when the mobile wireless communication device is locked. If the mobile wireless communication device is in an unlocked condition, the payment functionality of the contactless payment chip is enabled for use. In the situation where contactless payment is attempted, but the mobile wireless communication device is locked, the user may be prompted by any number of means, such as, for example, vibration, tone or message on a screen of the mobile wireless communication device, or an indication from the contactless payment reader, to enter the appropriate password to unlock the device and enable contactless payment. If the correct password is not entered for a predetermined number of attempts, use of the payment functionality of the contactless payment chip is disabled and the transaction is not completed.
In another embodiment, where the user may prefer a very rigorous and highly secure solution, entry of the password of the device in which the contactless payment chip is integrated, such as, for example, a mobile wireless communication device, may be required whenever a contactless payment transaction is attempted, regardless of the locked or unlocked condition of the device in which the contactless payment chip is integrated.
In yet another advantageous embodiment, the user may be required to enter a password to enable use of the payment functionality of the contactless payment chip once every predetermined number of contactless payment transactions. For example, the device may be set to request entry of a password upon the occurrence of every tenth contactless payment transaction. The device keeps track of the number of contactless payment transactions. Upon detection of the tenth attempted transaction, the device will prompt the user for entry of the appropriate password. If the correct password is entered, the transaction is enabled, and the counter which keeps track of the number of attempted contactless payment transactions is reset to zero. If the correct password is not entered after a predetermined number of attempts, use of the payment functionality of the contactless payment chip is disabled. This exemplary embodiment reduces the amount of potential loss, while maintaining a relatively high level of convenience for the user.
In another exemplary embodiment, contactless payment functionality may be associated with a so-called “smart card.” In this example, the smart card may include a chip that provides contactless payment functionality. The smart card having contactless payment functionality may be inserted into a smart card reader that is in communication with, for example, a mobile wireless communication device via a wireless connection, such as, for example, a Bluetooth™ connection. Additionally, the smart card reader may be a portable reader that is wearable by the user via, for example, a lanyard, or the like. When the smart card reader containing the smart card (including contactless payment functionality) is brought in proximity of a contactless payment reader, use of the contactless payment functionality may be controlled by the mobile wireless communications device in a manner similar to that described above, by controlling the smart card reader via wireless connection between the smart card reader and the mobile wireless communication device. For example, the mobile wireless communication device may include password functionality that is typically used to enable use of the mobile wireless communications device for features other than contactless payment, such as, for example, locking the mobile wireless communication device keypad. If there is no password set for the mobile wireless communication device, then the contactless payment chip is always enabled for use. However, if the password of the mobile electronic communication device is set, use of the payment functionality of the contactless payment chip may be disabled via the smart card reader when the mobile wireless communication device is locked. If the mobile wireless communication device is in an unlocked condition, the payment functionality of the contactless payment chip is enabled for use by the smart card reader. In the situation where contactless payment is attempted, but the mobile wireless communication device is locked, the user may be prompted by any number of means, such as, for example, vibration, tone or message on a screen of the mobile wireless communication device, or an indication from the contactless payment reader, to enter the appropriate password to unlock the device via the smart card reader and enable contactless payment. If the correct password is not entered for a predetermined number of attempts, use of the payment functionality of the contactless payment chip is disabled and the transaction is not completed. It will be understood that other security schemes using the security features of the mobile wireless communication device may be used, and other uses of the password functionality, such as those described above in connection with different exemplary embodiments may be used.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other embodiments together with their attendant advantages are described herein with reference to the following drawings in which like reference numerals refer to like elements, and wherein:
FIG. 1 is a block diagram illustrating an exemplary contactless payment system;
FIG. 2 is a block diagram of a wireless mobile communication device as an example of an electronic device having an integrated contactless payment chip and antenna;
FIG. 3 is a flow diagram illustrating a method of contactless payment authentication according to an exemplary embodiment;
FIG. 4 is a flow diagram illustrating a method of contactless payment authentication according to another exemplary embodiment;
FIG. 5 is a flow diagram illustrating yet another method of contactless payment authentication according to another exemplary embodiment; and
FIG. 6 is an illustrative schematic block diagram of an exemplary contactless payment system employing a smart card and portable smart card reader.
DETAILED DESCRIPTION OF THE EMBODIMENTS
FIG. 1 is a block diagram illustrating an exemplary contactless payment system 10 . According to this illustrative example, a contactless payment device 100 , such as, for example, a contactless payment card, key fob, cellular telephone, mobile wireless communication device, or the like, is equipped with an integrated contactless payment chip 110 and radio-frequency antenna 130 . The chip 110 includes consumer account information 120 that can be used by the system 10 to enable contactless payment transactions.
In operation, when a user desires to make a contactless payment, the user brings the contactless payment device 100 into close proximity of a contactless payment terminal or reader 140 . The contactless payment terminal or reader 140 emits a signal that will activate the antenna 130 associated with the contactless payment chip 110 of the contactless payment device 100 . Upon activation, the antenna 130 transmits the consumer account information 120 embedded in the contactless payment chip 110 to the contactless payment terminal or reader 140 . Upon receipt of the consumer account information 120 from the contactless payment device 100 , the contactless payment terminal or reader 140 transmits the consumer account information 120 to a transaction processing system 160 via a communications network 150 , such as, for example, a secure communications or computer network.
The transaction processing system 160 verifies the consumer account information 120 received from the contactless payment terminal or reader 140 . The transaction processing system 160 then provides an indication to the contactless payment terminal or reader 140 via, for example, the communication network 150 , whether the transaction is approved or declined.
FIG. 2 is a block diagram of an exemplary wireless mobile communication device as an example of an electronic device in which a contactless payment chip 110 and antenna 130 may be embedded and/or integrated for providing contactless payment functionality. However, it should be understood that the systems and methods disclosed herein may be used with many different types of devices, such as personal digital assistants (PDAs), cellular telephones, or the like.
The mobile device 500 is preferably a two-way communication device having at least voice and data communication capabilities. The mobile device 500 preferably has the capability to communicate with other computer systems on the Internet. Depending on the functionality provided by the mobile device, the mobile device may be referred to as a data messaging device, a two-way pager, a cellular telephone with data messaging capabilities, a wireless Internet appliance, or a data communication device (with or without telephony capabilities). As mentioned above, such devices are referred to generally herein as mobile devices.
The mobile device 500 includes a transceiver 511 , a microprocessor 538 , a display 522 , non-volatile memory 524 , random access memory (RAM) 526 , auxiliary input/output (I/O) devices 528 , a serial port 530 , a keyboard 532 , a speaker 534 , a microphone 536 , a short-range wireless communications sub-system 540 , and may also include other device sub-systems 542 . The transceiver 511 preferably includes transmit and receive antennas 516 , 518 , a receiver (Rx) 512 , a transmitter (Tx) 514 , one or more local oscillators (LOs) 513 , and a digital signal processor (DSP) 520 . Within the non-volatile memory 524 , the mobile device 500 includes a plurality of software modules 524 A- 524 N that can be executed by the microprocessor 538 (and/or the DSP 520 ), including a voice communication module 524 A, a data communication module 524 B, and a plurality of other operational modules 524 N for carrying out a plurality of other functions. The mobile device 500 may also include a contactless payment chip 110 and associated antenna 130 that may optionally be operatively coupled to the microprocessor 538 of the mobile device 500 to provide contactless payment functionality.
The mobile device 500 is preferably a two-way communication device having voice and data communication capabilities. Thus, for example, the mobile device 500 may communicate over a voice network, such as any of the analog or digital cellular networks, and may also communicate over a data network. The voice and data networks are depicted in FIG. 2 by the communication tower 519 . These voice and data networks may be separate communication networks using separate infrastructure, such as base stations, network controllers, etc., or they may be integrated into a single wireless network. References to the network 519 should therefore be interpreted as encompassing both a single voice and data network and separate networks.
The communication subsystem 511 is used to communicate with the network 519 . The DSP 520 is used to send and receive communication signals to and from the transmitter 514 and receiver 512 , and also exchange control information with the transmitter 514 and receiver 512 . If the voice and data communications occur at a single frequency, or closely-spaced set of frequencies, then a single LO 513 may be used in conjunction with the transmitter 514 and receiver 512 . Alternatively, if different frequencies are utilized for voice communications versus data communications or the mobile device 500 is enabled for communications on more than one network 519 , then a plurality of LOs 513 can be used to generate frequencies corresponding to those used in the network 519 . Although two antennas 516 , 518 are depicted in FIG. 2 , the mobile device 500 could be used with a single antenna structure. Information, which includes both voice and data information, is communicated to and from the communication module 511 via a link between the DSP 520 and the microprocessor 538 .
The detailed design of the communication subsystem 511 , such as frequency band, component selection, power level, etc., is dependent upon the communication network 519 in which the mobile device 500 is intended to operate. For example, a mobile device 500 intended to operate in a North American market may include a communication subsystem 511 designed to operate with the Mobitex or DataTAC mobile data communication networks and also designed to operate with any of a variety of voice communication networks, such as AMPS, TDMA, CDMA, PCS, etc., whereas a mobile device 500 intended for use in Europe may be configured to operate with the GPRS data communication network and the GSM voice communication network. Other types of data and voice networks, both separate and integrated, may also be utilized with the mobile device 500 .
Communication network access requirements for the mobile device 500 also vary depending upon the type of network 519 . For example, in the Mobitex and DataTAC data networks, mobile devices are registered on the network using a unique identification number associated with each device. In GPRS data networks, however, network access is associated with a subscriber or user of the mobile device 500 . A GPRS device typically requires a subscriber identity module (“SIM”), which is required in order to operate the mobile device 500 on a GPRS network. Local or non-network communication functions (if any) may be operable, without the SIM, but the mobile device 500 is unable to carry out functions involving communications over the network 519 , other than any legally required operations, such as “911” emergency calling.
After any required network registration or activation procedures have been completed, the mobile device 500 is able to send and receive communication signals, preferably including both voice and data signals, over the network 519 . Signals received by the antenna 516 from the communication network 519 are routed to the receiver 512 , which provides for signal amplification, frequency down conversion, filtering, channel selection, etc., and may also provide analog to digital conversion. Analog to digital conversion of the received signal allows more complex communication functions, such as digital demodulation and decoding, to be performed using the DSP 520 . In a similar manner, signals to be transmitted to the network 519 are processed, including modulation and encoding, for example, by the DSP 520 and are then provided to the transmitter 514 for digital to analog conversion, frequency up conversion, filtering, amplification and transmission to the communication network 519 via the antenna 518 . Although a single transceiver 511 is shown for both voice and data communications, in alternative embodiments, the mobile device 500 may include multiple distinct transceivers, such as a first transceiver for transmitting and receiving voice signals, and a second transceiver for transmitting and receiving data signals, or a first transceiver configured to operate within a first frequency band, and a second transceiver configured to operate within a second frequency band.
In addition to processing the communication signals, the DSP 520 also provides for receiver and transmitter control. For example, the gain levels applied to communication signals in the receiver 512 and transmitter 514 may be adaptively controlled through automatic gain control algorithms implemented in the DSP 520 . Other transceiver control algorithms could also be implemented in the DSP 520 in order to provide more sophisticated control of the transceiver 511 .
The microprocessor 538 preferably manages and controls the overall operation of the mobile device 500 . Many types of microprocessors or microcontrollers could be used here, or, alternatively, a single DSP 520 could be used to carry out the functions of the microprocessor 538 . Low-level communication functions, including at least data and voice communications, are performed through the DSP 520 in the transceiver 511 . High-level communication applications, including the voice communication application 524 A, and the data communication application 524 B are stored in the non-volatile memory 524 for execution by the microprocessor 538 . For example, the voice communication module 524 A may provide a high-level user interface operable to transmit and receive voice calls between the mobile device 500 and a plurality of other voice devices via the network 519 . Similarly, the data communication module 524 B may provide a high-level user interface operable for sending and receiving data, such as e-mail messages, files, organizer information, short text messages, etc., between the mobile device 500 and a plurality of other data devices via the network 519 .
The microprocessor 538 also interacts with other device subsystems, such as the display 522 , RAM 526 , auxiliary I/O devices 528 , serial port 530 , keyboard 532 , speaker 534 , microphone 536 , a short-range communications subsystem 540 and any other device subsystems generally designated as 542 . For example, the modules 524 A-N are executed by the microprocessor 538 and may provide a high-level interface between a user of the mobile device and the mobile device. This interface typically includes a graphical component provided through the display 522 , and an input/output component provided through the auxiliary I/O devices 528 , keyboard 532 , speaker 534 , or microphone 536 . Additionally, the microprocessor 538 is capable of running a variety of applications that may be present in the device non-volatile memory 524 , including applications that have access to various privileges, as will be described in more detail herein.
Some of the subsystems shown in FIG. 2 perform communication-related functions, whereas other subsystems may provide “resident” or on-device functions. Notably, some subsystems, such as keyboard 532 and display 522 may be used for both communication-related functions, such as entering a text message for transmission over a data communication network, and device-resident functions such as a calculator or task list or other PDA type functions. Another example of an application that may be controlled by the microprocessor 538 of the mobile device 500 is the password protection of the device 500 , wherein operation of the device or keyboard may be made dependent upon the locking or unlocking of the device 500 using, for example, a password entered via the keyboard 532 , or the like.
Operating system software used by the microprocessor 538 is preferably stored in a persistent store such as the non-volatile memory 524 . In addition to the operating system and communication modules 524 A-N, the non-volatile memory 524 may include a file system for storing data. The non-volatile memory 524 may also include data stores for owner information and owner control information. The operating system, specific device applications or modules, or parts thereof, may be temporarily loaded into a volatile store, such as RAM 526 for faster operation. Moreover, received communication signals may also be temporarily stored to RAM 526 , before permanently writing them to a file system located in the non-volatile memory 524 . The non-volatile memory 524 may be implemented, for example, with Flash memory, non-volatile RAM, or battery backed-up RAM.
An exemplary application module 524 N that may be loaded onto the mobile device 500 is a PIM application providing PDA functionality, such as calendar events, appointments, and task items. This module 524 N may also interact with the voice communication module 524 A for managing phone calls, voice mails, etc., and may also interact with the data communication module 524 B for managing e-mail communications and other data transmissions. Alternatively, all of the functionality of the voice communication module 524 A and the data communication module 524 B may be integrated into the PIM module.
The non-volatile memory 524 preferably provides a file system to facilitate storage of PIM data items on the device. The PIM application preferably includes the ability to send and receive data items, either by itself, or in conjunction with the voice and data communication modules 524 A, 524 B, via the wireless network 519 . The PIM data items are preferably seamlessly integrated, synchronized and updated, via the wireless network 519 , with a corresponding set of data items stored or associated with a host computer system, thereby creating a mirrored system for data items associated with a particular user.
The mobile device 500 is manually synchronized with a host system by placing the mobile device 500 in an interface cradle, which couples the serial port 530 of the mobile device 500 to a serial port of the host system. The serial port 530 may also be used to insert owner information and owner control information onto the mobile device 500 and to download other application modules 524 N for installation on the mobile device 500 . This wired download path may further be used to load an encryption key onto the mobile device 500 for use in secure communications, which is a more secure method than exchanging encryption information via the wireless network 519 .
Owner information, owner control information and additional application modules 524 N may be loaded onto the mobile device 500 through the network 519 , through an auxiliary I/O subsystem 528 , through the short-range communications subsystem 540 , or through any other suitable subsystem 542 , and installed by a user in the non-volatile memory 524 or RAM 526 . Such flexibility in application installation increases the functionality of the mobile device 500 and may provide enhanced on-device functions, communication-related functions, or both. For example, secure communication applications may enable electronic commerce functions and other such financial transactions to be performed using the mobile device 500 .
When the mobile device 500 is operating in a data communication mode, a received signal, such as a text message or a web page download, will be processed by the transceiver 511 and provided to the microprocessor 538 , which preferably further processes the received signal for output to the display 522 , or, alternatively, to an auxiliary I/O device 528 . Owner information, owner control information, commands or requests related to owner information or owner control information, and software applications received by the transceiver 511 are processed as described above. A user of mobile device 500 may also compose data items, such as email messages, using the keyboard 532 , which is preferably a complete alphanumeric keyboard laid out in the QWERTY style, although other styles of complete alphanumeric keyboards such as the known DVORAK style may also be used. User input to the mobile device 500 is further enhanced with the plurality of auxiliary I/O devices 528 , which may include a thumbwheel input device, a touchpad, a variety of switches, a rocker input switch, etc. The composed data items input by the user are then transmitted over the communication network 519 via the transceiver 511 .
When the mobile device 500 is operating in a voice communication mode, the overall operation of the mobile device 500 is substantially similar to the data mode, except that received signals are output to the speaker 534 and voice signals for transmission are generated by a microphone 536 . In addition, the secure messaging techniques described above might not necessarily be applied to voice communications. Alternative voice or audio I/O devices, such as a voice message recording subsystem, may also be implemented on the mobile device 500 . Although voice or audio signal output is accomplished through the speaker 534 , the display 522 may also be used to provide an indication of the identity of a calling party, the duration of a voice call, or other voice call related information. For example, the microprocessor 538 , in conjunction with the voice communication module 524 A and the operating system software, may detect the caller identification information of an incoming voice call and display it on the display 522 .
A short-range communications subsystem 540 is also be included in the mobile device 500 . For example, the subsystem 540 may include an infrared device and associated circuits and components, or a Bluetooth or 802.11 short-range wireless communication module to provide for communication with similarly-enabled systems and devices. Thus, owner information insertion, owner control information insertion, and application loading operations as described above may be enabled on the mobile device 500 via the serial port 530 or other short-range communications subsystem 540 .
The exemplary mobile device 500 described herein may also include an embedded or integrated contactless payment chip 110 and antenna 130 , such as that described above. As such, the mobile device 500 is provided with optional contactless payment functionality that may include a degree of password protection as will be illustratively described herein with reference to FIGS. 3-5 .
FIG. 2 represents a specific example of an electronic device in which contactless payment systems and methods described herein may be implemented. Implementation of such systems and methods in other electronic devices having further, fewer, or different components than those shown in FIG. 2 would occur to one skilled in the art to which this application pertains and are therefore considered to be within the scope of the present application.
FIG. 3 is a flow diagram illustrating a method of contactless payment authentication according to an exemplary embodiment. In this example, upon detection of an attempted use of a contactless payment chip 300 that is, for example, embedded in a mobile wireless communication device 500 , an inquiry is made to determine whether the device 500 has authentication functionality, such as, for example, password protection functionality enabled 310 . Detection of an attempted use of the contactless payment chip may be determined in any number of ways, such as, for example, detection of activation of the antenna 130 . If, in step 310 , it is determined that there is no password protection, or that password protection features are not enabled, the device 500 enables use of the payment functionality of the embedded contactless payment chip 110 to complete the transaction 320 . On the other hand, if in step 310 it is determined that the device 500 has enabled password features, the device 500 determines whether the device is locked 330 . If the device is not locked, the device 500 enables use of the payment functionality of the embedded contactless payment chip 110 to complete the transaction 320 . If the device is locked, the user is prompted to enter the password 340 using, for example, the keyboard 532 of the device 500 . As described above, the user may be prompted by any number of methods, such as, for example, vibration of the device, emission of a tone by the device, display of a message on the device screen, a message on the contactless payment reader, etc. If the correct password is entered 350 , then the device 500 enables use of the payment functionality of the embedded contactless payment chip 110 to complete the transaction 320 . On the other hand, if the incorrect password is entered 350 , the device 500 disables use of the contactless payment functions 360 . Disabling use of the payment functionality of the chip 110 may be achieved by any number of acceptable means, such as, for example, and without limitation, disabling the antenna 130 so that transmission of payment related data from the chip to the payment terminal 140 , smart card reader 770 , or the like. Alternatively, a predetermined number of attempts to enter the correct password may be allowed to allow the user some flexibility and to avoid unnecessary denial of access.
In this manner, a certain level of security is provided to the contactless payment functionality via the device 500 . This security level is not intrusive and can be set to any level desired by the user. For example, the user may desire no security whatsoever, in which case the user may set the device to not use password protection at all. Alternatively, the device may only be locked at certain times, and may be unlocked for long periods of time. Of course, the device may be locked upon the occurrence of any event, which would provide a very high, albeit somewhat intrusive, level of security. In any event, the level of security is determined based on a comfort level of the user. It will also be understood that the authentication functionality may be implemented in any suitable manner including, but not limited to, being implemented on a processor of the device or a by a server that may run various applications specific to the device or system.
In another embodiment, as illustrated in the flow diagram of FIG. 4 , a more intrusive, but highly secure method of contactless payment authentication is disclosed. According to this example, upon detection of attempted use of the embedded contactless payment functionality 400 , as described above, a determination is made as to whether the device 500 has authentication functionality, such as, for example, password functionality enabled 410 . If password functionality is not enabled or if the device does not have any password functionality, use of the contactless payment functionality is enabled 420 . If the device 500 does have password functionality that is enabled 410 , the user is prompted for the password 430 . As described above, the user may be prompted by any number of methods, such as, for example, vibration of the device, emission of a tone by the device, display of a message on the device screen, a message on the contactless payment reader, etc. After entry of the password 440 , it is determined whether the password is correct 450 . If the password entered by the user 440 is correct, use of the contactless payment functionality is enabled 420 . If the password entered by the user is incorrect, the use of contactless payment functionality is disabled 460 . As described above, the system may be designed to allow a predetermined number of password entry attempts prior to disabling the use of contactless payment functionality.
The illustrative example set forth in FIG. 4 is the most secure, but is also the most intrusive and time consuming. However, for those who value security over convenience and time savings, the solution set forth in this example may be preferred. As set forth above, it will be understood that the authentication functionality may be implemented in any suitable manner including, but not limited to, being implemented on a processor of the device or a by a server that may run various applications specific to the device or system.
Turning now to FIG. 5 , another method of contactless payment authentication according to another exemplary embodiment is illustrated. According to this example, the device 500 is set to check for an authentication code, such as, for example, a password upon the detection of a predetermined number of contactless payment attempts. In this manner, a certain level of security is provided wherein limitless unauthorized use of the embedded contactless payment functionality is prevented, while minimizing the intrusiveness and inconvenience that may be associated with password verification of contactless payments. In this example, a counter that keeps track of the number of contactless payment attempts is first set to zero 600 . Each time a contactless payment attempt is detected 610 by the device 500 , the counter is incremented 620 . The counter is checked 630 each time a contactless payment is attempted 610 . So long as the counter is determined to be less than a predetermined number 630 , use of contactless payment functionality embedded in the device 500 is enabled 640 . If the counter is determined to be greater than or equal to the predetermined number of attempts 630 , the user is prompted to enter the password 650 . As described above, the user may be prompted by any number of methods, such as, for example, vibration of the device, emission of a tone by the device, display of a message on the device screen, a message on the contactless payment reader, etc. After entry of the password 660 , it is determined whether the password is correct 670 . If the password entered by the user 670 is correct, use of the contactless payment functionality is enabled 690 and the counter is reset to zero 600 . If the password entered by the user is incorrect, the use of contactless payment functionality is disabled 680 . As described above, the system may be designed to allow a predetermined number of password entry attempts prior to disabling the use of contactless payment functionality.
In this example, the user may have to supply their password once in every predetermined number of contactless payment attempts. Operating the contactless payment system according to this embodiment would reduce user interaction and inconvenience, while at the same time reducing the amount of unlawful or unauthorized usage. As described above, the system may be designed to allow a predetermined number of password entry attempts prior to disabling the use of contactless payment functionality.
In another example, as illustrated in FIG. 6 , contactless payment functionality may be associated with a so-called smart card 700 . In this example, the smart card 700 may include a chip 710 that provides contactless payment functionality via consumer account information 710 resident on the chip, and an antenna 730 that is used to transmit information to a contactless payment reader 740 . The smart card 700 having contactless payment functionality may be inserted into a smart card reader 770 that is in communication with, for example, a mobile wireless communication device 780 via a wireless connection, such as, for example, a Bluetooth™ connection. Additionally, the smart card reader 770 may be a portable reader that is wearable by the user via, for example, a lanyard (not shown), or the like. When the smart card reader 770 containing the smart card (including contactless payment functionality) 700 is brought in proximity of a contactless payment reader 740 , use of the contactless payment functionality may be controlled by the mobile wireless communications device 780 in a manner similar to that described above, by controlling the smart card reader 770 via wireless connection between the smart card reader 770 and the mobile wireless communication device 780 . As described above, when the contactless payment terminal 740 receives consumer account information 710 from the smart card 700 via the antenna 730 , this information is sent to a transaction processing system 760 over a communication network 750 . The transaction processing system 760 authenticates the consumer account information 710 and sends an indication to the contactless payment terminal 740 , via the communication network 750 , as to whether the transaction is authorized.
As set forth above, security features of the mobile wireless communication device 780 may be used to control the transmission of consumer account information 710 when the smart card reader 770 is in proximity to the contactless payment terminal 740 . For example, the mobile wireless communication device 780 may include password functionality that is typically used to enable use of the mobile wireless communications device for features other than contactless payment, such as, for example, locking the mobile wireless communication device 780 keypad. If there is no password set for the mobile wireless communication device 780 , then the payment functionality of the contactless payment chip is always enabled for use. However, if the password of the mobile electronic communication device 780 is set, use of the payment functionality of the contactless payment chip 710 may be disabled via the smart card reader 770 when the mobile wireless communication device 780 is locked. If the mobile wireless communication device 780 is in an unlocked condition, contactless payment functionality is enabled for use by the smart card reader 770 . In the situation where contactless payment is attempted, but the mobile wireless communication device 780 is locked, the user may be prompted by any number of means, such as, for example, vibration, tone or message on a screen of the mobile wireless communication device 780 , or an indication from the contactless payment reader 740 , to enter the appropriate password to unlock the device via the smart card reader 770 and enable contactless payment. If the correct password is not entered for a predetermined number of attempts, the contactless payment functionality is disabled and the transaction is not completed. It will be understood that other security schemes using the security features of the mobile wireless communication device may be used, and other uses of the password functionality, such as those described above in connection with different exemplary embodiments may be used, such as, for example, those described above in connection with FIGS. 3-5 .
While this disclosure describes specific exemplary embodiments, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the exemplary embodiments described herein, are intended to be illustrative, not limiting. Various changes may be made without departing from the true spirit and full scope of the invention, as defined in the following claims. | A computer-readable medium contains computer-executable instructions. When the instructions are performed by a processor in an electronic device having embedded contactless payment functionality, the performance of the instructions causes the processor to provide data for a contactless payment transaction. In particular, various systems and methods utilize authentication schemes that already exist on a device in which the contactless payment functionality is embedded. One example of such authentication schemes is the use of password protection to lock or unlock the device in which the contactless payment functionality is embedded. Using the password protection functionality may provide varying levels of authentication protection based on the desires of the user. A number of exemplary uses of such a method and apparatus are disclosed herein. | 6 |
PRIORITY CLAIM
This application claims benefit, under U.S.C. §119 or §365 of French Application Number FR 0605284, filed Jun. 14, 2006; U.S. 60/838,011, filed Aug. 16, 2006; and PCT/FR2007/051390 filed Jun. 8, 2007.
FIELD OF THE INVENTION
The present invention relates to novel copolymers based on amide units and on polyether units, these copolymers being typically transparent and being amorphous or exhibiting a crystallinity ranging from a “very slight semicrystallinity” to an “intermediate crystallinity”.
BACKGROUND OF THE INVENTION
In order to better characterize the invention and the problem which it solves, five categories of existing polyamide materials will be mentioned. The term “polyamide materials” is understood to mean compositions based on polyamides, copolyamides and polyamide alloys or based on polyamides.
(1) Impact-Modified Polyamide Materials (High-Impact PA)
These are alloys of polyamide with a minor amount of elastomer, typically in the vicinity of 20% by weight. The polyamide is typically a semicrystalline polyamide. These alloys have the advantage of a very good impact strength, much improved with respect to polyamide alone, typically three times better or more. They also have good chemical resistance and satisfactory resistance to distortion under heat (60° C.). They have the disadvantage of being opaque, which can be a problem for decorative components. A well-known example of high-impact polyamide is “Zytel ST801” from DuPont.
(2) Transparent Amorphous Polyamide Materials (TR amPA)
These are materials which are transparent, which are amorphous or not very semicrystalline (enthalpy of fusion during the DSC second heating of less than 30 J/g), which are rigid (flexural modulus ISO>1300 MPa) and which do not distort under heat, at 60° C., as they have a glass transition temperature Tg of greater than 75° C. However, they are rather unresistant to impacts, exhibiting a much lower notched Charpy ISO impact in comparison with impact-modified polyamides, and their chemical resistance is not excellent, in particular due to their amorphous nature. There also exists (but these are materials less frequently encountered) transparent semicrystalline (or microcrystalline) polyamides, typically with enthalpies of fusion during the DSC second heating between 2 and 30 J/g, these materials also being fairly rigid and having a flexural modulus ISO>1000 MPa.
(3) Polyether-Block-Amide and Copolymers Comprising Ether and Amide Units (PEBA)
These are copolyamides based on ether units and on amide units, polyetheramides and in particular polyether-block-amides (PEBAs). These are very flexible highly impact-resistant materials but with a fairly low transparency (45 to 65% of light transmission at 560 nm for a thickness of 2 mm), just like their polyamide homologues without ether units.
(4) Semicrystalline Polyamides (PA)
These are typically linear aliphatic polyamides. Their crystallinity is reflected by the presence of spherolites, the size of which is sufficiently great for the material not to be highly transparent (light transmission of less than 75%).
(5) Transparent Semicrystalline Polyamides (TR scPA)
These are more specifically microcrystalline polyamides where the size of the spherolites is sufficiently small to retain the transparency; (see European Patents EP 550 308 and EP 725 101) (transparency>75%).
The various properties of the five categories of polyamides which have just been indicated have been summarized in Table 1A below:
TABLE 1A
Impact/
Tempera-
Chemical
Polyamide
Transparency
breaking
Flexibility
ture
resistance
Elastic
Processing
category
(a)
strength (b)
c)
stability (d)
(e)
fatigue (f)
(g)
(1) High-impact
−−−
+++
+
++
+++
+
+++
PA
(2) TR amPA (1)
+++
−
− to −−−
++ to +++
− to −−−
−− to +
−
(3) PEBA (2)
−− to +
+ to +++
+ to +++
+ to ++
+ to ++
+++
++ to +++
(4) PA
−− to −
+
+
++
+++
+
+++
(5) TR scPA
++ to +++
+
− to +
− to +
+ to +++
− to +
−
Grades from −−− = very bad to +++ = very good
DEFINITIONS OF TABLE 1A
(a) Transparency: is characterized by the measurement of transmission at 560 nm through a polished sheet with a thickness of 2 mm.
(b) Impact/breaking strength: is characterized by a rapid folding test or by a notched Charpy impact ISO179.
(c) Flexibility: is characterized by the flexural modulus ISO178.
(d) Temperature stability: ability of the polyamide not to be distorted if it is placed in a hot atmosphere, at approximately 60° C., and under the effect of a relatively great weight.
(e) Chemical resistance: ability of the polyamide not to be damaged (matifying, cracking, splitting, breaking) on contact with a chemical (alcohol, and the like) and in particular if it is placed under stress, that is to say “stress cracking”.
(f) Elastic fatigue: ability of the polyamide to be folded a large number of times without breaking, elastic rebound, for example “Ross-Flex” test.
(g) Processing: ability of the polyamide to be easily processed by an injection-moulding process (short cycle time, easy removal from the mould, undistorted component).
The aim of the invention is to find novel transparent compositions which are impact resistant, which are not too rigid and even up to very flexible, which behave well towards or are resistant to distortion under heat (60° C.) and/or which have good chemical resistance. The ability to withstand alternating bending (fatigue) and the ability to be easily processed by injection-moulding are also qualities which may be looked for. In other words, the aim has been to find a composition combining most of, or at least a larger number of, the advantages of the first three categories above (high-impact PA, TR amPA, PEBA).
The PEBA copolymers belong to the specific category of the polyetheresteramides when they result from the copolycondensation of polyamide sequences comprising reactive carboxyl ends with polyether sequences comprising reactive ends, which are polyether polyols (polyether diols), the bonds between the polyamide blocks and the polyether blocks being ester bonds, or alternatively to the category of the polyetheramides when the polyether sequences comprise amine ends.
Various PEBAs are known for their physical properties, such as their flexibility, their impact strength or their ease of processing by injection-moulding.
The improvement in the transparency of PEBAs has already formed the subject of various research studies.
French Patent FR 2 846 332 discloses the use of PEBAs in which the polyamide block is a microcrystalline copolyamide immiscible with the polyether block. In particular, Example 1 describes a polyamide based on Jun. 11, 1912, which is regulated with adipic acid and which is coupled with polytetramethylene glycol (abbreviated to PTMG). However, these copolymers have a glass transition temperature Tg of approximately 70° C. For this reason, this copolymer softens and distorts excessively as soon as the temperature approaches the Tg, from approximately 60° C., which is frequently encountered under the conditions of normal life of the product, for example under a motor vehicle windscreen or inside a container right in the sun. Furthermore, this copolymer does not comprise a cycloaliphatic unit.
Generally, known copolymers comprising ether and amide units are composed of semicrystalline and linear aliphatic polyamide sequences (for example, the “Pebax” products from Arkema, or the “Vestamid E” products from Degussa).
The Applicant Company has discovered, surprisingly, that if, on the contrary, use is made of polyamide monomers of cycloaliphatic and thus nonlinear aliphatic nature and if they are copolymerized with polyethers, transparent and amorphous or only very slightly semicrystalline copolymers are obtained. What is more, materials which are resistant to distortion under heat at 60° C. (as the glass transition temperature Tg is greater than or equal to 75° C.) and which have very good impact strength and good flexibility are obtained.
SUMMARY OF THE INVENTION
The subject-matter of the present invention is thus a copolymer based on amide units and on ether units, the amide units being composed predominantly of an equimolar combination of at least one diamine and of at least one dicarboxylic acid, the diamine or diamines being predominantly cycloaliphatic and the dicarboxylic acid or acids being predominantly linear aliphatic, it being possible for the amide units optionally to comprise, but to a minor extent, at least one other polyamide comonomer, the respective proportions of monomers of the ether and amide units being chosen so that:
the said copolymer exhibits a high transparency which is such that the transmission at 560 nm through a sheet with a thickness of 2 mm is greater than 75%; the said copolymer is amorphous or exhibits a crystallinity such that the enthalpy of fusion (delta Hm(2)) during the second heating of an ISO DSC is at most equal to 30 J/g, the weight being with respect to the amount of amide units present or of polyamide present, this melting corresponding to that of the amide units; the said copolymer has a glass transition temperature at least equal to 75° C.
DETAILED DESCRIPTION OF THE INVENTION
The term “predominantly” is understood to mean “in a proportion of more than 50% by weight (>50%)”.
The expression “to a minor extent” is understood to mean “in a proportion of less than 50% by weight (<50%)”.
The term “delta Hm(2)” is understood to mean the enthalpy of fusion during the second heating of a DSC according to the ISO standard, DSC being Differential Scanning Calorimetry.
The cycloaliphatic diamine or diamines according to the present invention are advantageously chosen from bis(3-methyl-4-aminocyclohexyl)methane (BMACM), para-aminodicyclohexylmethane (PACM), isophoronediamine (IPD), bis(4-amino-cyclohexyl)methane (BACM), 2,2-bis(3-methyl-4-aminocyclohexyl)propane (BMACP) or 2,6-bis(aminomethyl)norbornane (BAMN).
Advantageously, just one cycloaliphatic diamine, in particular bis(3-methyl-4-aminocyclohexyl)methane, was used as diamine to produce the amide units.
At least one noncycloaliphatic diamine can participate in the composition of the monomers of the amide units, in a proportion of at most 30 mol % with respect to the diamines of the said composition. Mention may be made, as noncycloaliphatic diamine, of linear aliphatic diamines, such as 1,4-tetramethylenediamine, 1,6-hexamethylenediamine, 1,9-nonamethylenediamine and 1,10-decamethylenediamine.
The aliphatic dicarboxylic acid or acids can be chosen from aliphatic dicarboxylic acids having from 6 to 36 carbon atoms, preferably from 9 to 18 carbon atoms, in particular 1,10-decanedicarboxylic acid (sebacic acid), 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid and 1,18-octadecanedicarboxylic acid.
At least one nonaliphatic dicarboxylic acid can participate in the composition of the monomers of the amide units in a proportion of at most 15 mol % with respect to the dicarboxylic acids of the said composition. Preferably, the nonaliphatic dicarboxylic acid is chosen from aromatic diacids, in particular isophthalic acid (I), terephthalic acid (T) and their mixtures.
The lactam is, for example, chosen from caprolactam, oenantholactam and lauryllactam.
The α,ω-aminocarboxylic acid is, for example, chosen from aminocaproic acid, 7-aminoheptanoic acid, 11-aminoundecanoic acid or 12-aminododecanoic acid.
Advantageously, the PA blocks represent 50 to 95% by weight of the said copolymer.
The PA blocks are, for example, chosen from: BMACM.9, BMACM.10, BMACM.12, BMACM.14, BMACM.18 and their mixtures.
The number-average molecular weight of the PA blocks is advantageously between 500 and 12 000 g/mol, preferably between 2000 and 6000 g/mol.
The PE (polyether) blocks result, for example, from at least one polyalkylene ether polyol, in particular a polyalkylene ether diol, preferably chosen from polyethylene glycol (PEG), polypropylene glycol (PPG), polytrimethylene glycol (PO3G), polytetramethylene glycol (PTMG) and their blends or their copolymers.
The PE blocks can comprise polyoxyalkylene sequences comprising NH 2 chain ends, it being possible for such sequences to be obtained by cyanoacetylation of α,ω-dihydroxylated aliphatic polyoxyalkylene sequences, referred to as polyether diols. More particularly, use may be made of Jeffamines (for example Jeffamine® D400, D2000, ED 2003 or XTJ 542, commercial products from Huntsman. See also Patents JP 2004346274, JP 2004352794 and EP 1 482 011).
The number-average molecular weight of the PE blocks is advantageously between 200 and 4000 g/mol, preferably between 300 and 1100 g/mol.
The copolymer according to the invention can be amorphous or can have a crystallinity such that delta Hm(2) of the said copolymer is less than or equal to 10 J/g.
The copolymer according to the invention can also exhibit an intermediate crystallinity such that delta Hm(2) of the said copolymer is between 10 and 30 J/g, preferably between 10 and 25 J/g, the weight being with respect to the amount of amide units present or of polyamide present, this melting corresponding to that of the amide units. Such materials are products with behaviour intermediate between amorphous or essentially amorphous polymers, that is to say with an enthalpy of fusion of the second heating between 0 and 10 J/g, which are no longer in the solid state above their Tg, and truly semicrystalline polymers, which are polymers which remain in the solid state and thus which definitely retain their shape above their Tg. These products with intermediate behaviour are thus in a more or less solid state but can be easily deformed above their Tg. As their Tg is high, in so far as they are not used above this Tg, such materials are advantageous, all the more so as their chemical resistance is better than that of the amorphous materials. Example 32 of the present application illustrates such materials with intermediate behaviour.
The copolymer according to the present invention can advantageously be transparent with more than 75% of transmission at 550 nm through a thickness of 2 mm.
The copolymer according to the present invention can in addition advantageously comprise at least one additive chosen from heat stabilizers, UV stabilizers, colorants, nucleating agents, plasticizers or agents for improving the impact strength, the said additive or additives preferably having a refractive index similar to that of the said copolymer.
A specific form of the present invention consists in choosing a copolymer characterized in that its flexible ether units are chosen to be of highly hydrophilic nature, preferably of polyether block of PEG, PPG or PO3G type nature, which confers an advantageous increase in antistatic properties and waterproof-breathable (that is to say, allowing the passage of water vapour but not of liquid water) properties on the composition. Furthermore, this composition can be additivated by third-party antistatic additives, in order to strengthen the overall antistatic effect, and also by additives which make it possible to increase the blending compatibility with other polymers. The copolymer, alone or thus additivated, can subsequently be used as additive of another polymer or material in order to confer, on the latter, an increase in antistatic or waterproof-breathable properties.
Another subject-matter of the present invention is a process for the preparation of a copolymer as defined above, characterized in that:
in a first stage, the polyamide PA blocks are prepared by polycondensation
of the diamine or diamines; of the dicarboxylic acid or acids; and if appropriate, of the comonomer or comonomers chosen from lactams and α,ω-aminocarboxylic acids; in the presence of a chain-limiting agent chosen from dicarboxylic acids; then
in a second stage, the polyamide PA blocks obtained are reacted with polyether PE blocks in the presence of a catalyst.
The general method for the two-stage preparation of the copolymers of the invention is known and is disclosed, for example, in French Patent FR 2 846 332 and European Patent EP 1 482 011.
The reaction for the formation of the PA block is usually carried out between 180 and 300° C., preferably from 200 to 290° C., the pressure in the reactor is established between 5 and 30 bar and is maintained for approximately 2 to 3 hours. The pressure is slowly reduced by bringing the reactor to atmospheric pressure and then the excess water is distilled off, for example over one or two hours.
The polyamide comprising carboxylic acid ends having been prepared, the polyether and a catalyst are subsequently added. The polyether can be added on one or more occasions, and likewise for the catalyst. According to an advantageous form, first of all the polyether is added and the reaction of the OH ends of the polyether and of the COOH ends of the polyamide begins with formation of ester bonds and removal of water. As much as possible of the water is removed from the reaction medium by distillation and then the catalyst is introduced in order to bring to completion the bonding of the polyamide blocks and of the polyether blocks. This second stage is carried out with stirring, preferably under a vacuum of at least 15 mmHg (2000 Pa), at a temperature such that the reactants and the copolymers obtained are in the molten state. By way of example, this temperature can be between 100 and 400° C. and generally 200 and 300° C. The reaction is monitored by measuring the torsional couple exerted by the molten polymer on the stirrer or by measuring the electrical power consumed by the stirrer. The end of the reaction is determined by the target value of the couple or of the power.
It is also possible to add, during the synthesis, at the moment judged the most opportune, one or more molecules used as antioxidant, for example Irganox®11010 or Irganox® 245.
Another subject-matter of the present invention is a process for the preparation of a copolymer as defined above, characterized in that all the monomers are added at the start, i.e. in a single stage, to carry out the polycondensation:
of the diamine or diamines; of the dicarboxylic acid or acids; and if appropriate, of the other polyamide comonomer or comonomers; in the presence of a chain-limiting agent chosen from dicarboxylic acids; in the presence of the PE (polyether) blocks; in the presence of a catalyst for the reaction between the PE blocks and the PA blocks.
Advantageously, the said dicarboxylic acid, which is introduced in excess with respect to the stoichiometry of the diamine or diamines, is used as chain-limiting agent.
Advantageously, a derivative of a metal chosen from the group formed by titanium, zirconium and hafnium or a strong acid, such as phosphoric acid, hypophosphorous acid or boric acid, is used as catalyst.
The polycondensation can be carried out at a temperature of 240 to 280° C.
Another subject-matter of the present invention is a shaped article, in particular a transparent or translucent shaped article, such as fibre, fabric, film, sheet, rod, pipe or injection-moulded component, comprising the copolymer as defined above, or manufactured by a process as defined above.
Thus, the copolymer according to the present invention is advantageous in the ready manufacture of articles, in particular of sports equipment or components of sports equipment, which have in particular to simultaneously exhibit good transparency, good impact strength and good endurance with regard to mechanical assaults and attacks by chemicals, UV radiation and heat. Mention may be made, among this sports equipment, of components of sports shoes, sports gear, such as ice skates or other winter and mountaineering sports equipment, ski bindings, rackets, sports bats, boards, horseshoes, flippers, golf balls or recreational vehicles, in particular those intended for cold-weather activities.
Mention may also be made generally of recreational equipment, do-it-yourself equipment, highway gear and equipment subjected to attacks by the weather and to mechanical assaults, and protective articles, such as helmet visors, glasses and sides of glasses. Mention may also be made, as nonlimiting examples, of motor vehicle components, such as headlight protectors, rearview mirrors, small components of all-terrain motor vehicles, tanks, in particular for mopeds, motorbikes or scooters, subjected to mechanical assaults and attacks by chemicals, cosmetic articles subjected to mechanical assaults and attacks by chemicals, lipstick tubes, pressure gauges or attractive protective components, such as gas bottles. Furthermore, as regards the field of screws and bolts, as PMMA is particularly weak, it is difficult to screw it on. A transparent screw in a fairly soft material will be capable of preventing the PMMA from breaking when overdoing it in screwing it on.
The following examples illustrate the present invention without, however, limiting the scope thereof.
In these examples, the percentages are by weight, unless otherwise indicated, and the following abbreviations were used:
BMACM: 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane. PACM: 4,4′-diaminodicyclohexylmethane, which is found with variable ratios of isomers; it is thus possible to distinguish “PACM20” from Air Products and PACM richer in trans-trans isomer, Dicycan from BASF, which comprises more than 45% of trans-trans isomer and which will be referred to as “PACM45”. TA: terephthalic acid. IA: isophthalic acid. C14: tetradecanedioic acid. C12: dodecanedioic acid. C10: sebacic acid. C6: adipic acid. PTMG: a polyether, namely polytetramethylene glycol. PEG: polyethylene glycol. PE: polyether. In the case of diacid mixture, their proportions are indicated in moles (see Table 2).
Copolymers were prepared according to the following procedure:
Comparative Examples 1 to 3 of Transparent Polyamides
(see Table 2 below
General Procedure:
PAs based on cycloaliphatic diamine were prepared in 1 stage according to the following procedure:
The various monomers, plus 3% of water, were charged to an 80 l autoclave. The reactor, closed and purged with nitrogen, was heated to 270° C. under pressure and while stirring at 40 rpm. Conditions were maintained for 3 hours, then the pressure was reduced to atmospheric pressure over two hours and the polycondensation was continued under nitrogen at 280° C. (indeed even 300° C.) for approximately 2 hours in order to achieve the desired viscosity. The products were granulated. The 25 kg of polymer obtained were dried at 90° C. under vacuum.
Comparative Example 4
This is Example 1 described in French Patent FR 2 846 332, having PA 6/11/12 blocks and PTMG blocks.
Examples 6 to 10 According to the Invention
(see Tables 1B and 2 below)
General Procedure:
PEBAs were prepared in 2 stages from PA blocks based on cycloaliphatic diamine according to the following procedure:
Cycloaliphatic diamine and diacids were charged to an 80 l autoclave. The reactor, purged with nitrogen and closed, was heated to 260° C. under pressure and while stirring at 40 rpm. After maintaining for one hour, the pressure was reduced under atmospheric pressure and the polyether and the catalyst were added. The reactor was placed under vacuum over 30 minutes in order to reach 5 kPa (50 mbar) (if necessary 2 kPa (20 mbar)). The rise in the couple lasted approximately two hours. On achieving the viscosity, the reactor was brought back to atmospheric pressure and the product was granulated and dried under vacuum at 75° C.
TABLE 1B
Example 6
Example 7
Example 8
Example 9
Example 10
Monomer or
Amounts
Amounts
Amounts
Amounts
Amounts
starting material
charged (kg)
charged (kg)
charged (kg)
charged (kg)
charged (kg)
BMACM
16.446
16.446
14.313
11.805
13.309
C10 Sebacic acid
15.085
6.967
C14 Tetradecanedioic
17.039
8.126
8.117
acid
Dodecanedioic acid
9.27
7.135
7.160
PTMG 650
3.51
3.51
3.707
8.066
PTMG 1000
6.470
Water
0.5
0.5
0.5
0.5
0.5
Zirconium butoxide
45.5
45.5
45.5
45.5
45.5
(g)
For the other examples, the procedure is similar, as described in Table 3, in 1 stage or in 2 stages, as the case may be, the percentage of PE is expressed by weight, the Mn weights of the PA and PE units are shown (“Mn PE”, and “Mn PA” columns), the composition of the PA being described in moles (“diamine”, “diacid” columns, expressed in moles).
Examples 11 to 32
(see Table 3 below)
General Procedure:
PEBAs were prepared according to the following procedure. All the monomers were introduced into a glass reactor immersed in an oil bath and equipped with a stirrer. The mixture of approximately 60 g of cycloaliphatic diamine, of diacid and of polyethers thus formed was placed under an inert atmosphere and heated until the temperature reached 260° C. After polycondensing under nitrogen for approximately 1 hour, the catalyst Zr(OBu) 4 was added and the reactor was placed under vacuum (1 kPa to 5 kPa (10 to 50 mbar)) in order to bring the polymerization to an end at 260° C. Once the viscosity was reached, the reactor was again placed under nitrogen and cooled.
Example 11
The following were charged in one stage: 27.1 g of BMACM, 13.5 g of C10 diacid, 13.1 g of C12 diacid and 6.4 g of PTMG 650. The addition of the catalyst Zr(OBu) 4 is 0.4 ml. The chain-limiting agent is the C10 diacid. The C10/C12 molar ratio is 50/50.
For the copolymers of Examples 1 to 10, sheets of 100×100×2 mm were moulded by injection-moulding the said copolymers at 270° C. with a cold mould at 10° C.
For the copolymers of Examples 11 to 32, pellets were prepared by compressing at 270° C. under a press.
The optical and mechanical properties of these sheets or pellets were measured (see Tables 2 and 3).
DEFINITIONS OF TABLES 2 AND 3
h) Rise in viscosity: It represents the ability to be polymerized and consequently to produce a polymer of sufficient weight and thus of sufficient viscosity, which is reflected by an increase in the couple or in the power of the stirrer motor of the polymerizer. This rise in viscosity is produced under nitrogen or under vacuum. This rise in viscosity may be possible (recorded as “yes” in the tables which follow) or may not be possible (recorded as “no” in the tables which follow).
i) Tg: Inflection point (“Midpoint”) at the second pass by DSC, which is Differential Scanning Calorimetry ISO 11357.
i) Transparency: the transmission of the light at 560 nm is measured on sheets with a thickness of 2 mm. “VG” means that the transmission is >85%; “G” means that the transmission is >80% and “FG” means that the transmission is >75%.
k) Opacity—Transparency: corresponds to the contrast ratio and percentage of light transmitted or reflected at the wavelength of 560 nm on a sheet with a thickness of 2 mm.
l) MFI (melt flow index), measured at 275° C., 2.16 kg: The higher the MFI, the easier the synthesis of the copolymer.
m) Stiffness (flexibility): It is characterized by the measurement of the flexural modulus on a bar of 80×10×4 mm according to Standard ISO178. It is also characterized by the measurement of the E′ modulus obtained during a DMA test, which is a Differential Mechanical Analysis ISO 6721.
n) Elasticity and fatigue: The coefficient α (alpha) is determined graphically during an analysis of responsiveness (amplitude as a function of time). The higher the value, the more responsive and elastic the material. The fatigue behaviour is characterized by a Ross-Flex test ASTM1052 at −10° C. on an unpierced test specimen which is bent alternately by 90°. The number of cycles withstood before breaking is measured.
o) Elongation at break (%): The tension is measured on a test specimen of dumbbell type according to Standard ISOR527.
p) Viscosity: The intrinsic viscosity in dl/g is measured from 0.5 g of product dissolved at 25° C. in metacresol.
q) Yellowing: The yellow index is measured on granules (Table 2) or is estimated qualitatively (Table 3): “0” corresponds to no yellowing, “+” to slight yellowing, “++” to significant yellowing.
r) Semicrystalline: A semicrystalline polymer, in particular a polyamide, is a polymer which has a melting point with a significant enthalpy of fusion (recorded as delta Hm(2)), of greater than 10 J/g, preferably of greater than 25 j/g (measurement carried out during an ISO DSC, during the second heating), which means that the polymer retains an essentially solid state above its glass transition temperature (Tg).
s) Amorphous: An amorphous polymer, in particular a polyamide, is a polymer which does not have a melting point or which has a not very marked melting point, that is to say with an enthalpy of fusion of less than 10 J/g, measurement carried out during an ISO DSC, during the second heating. This polymer thus leaves its solid state above its glass transition temperature (Tg).
t) Antistatic effects: The antistatic effect is characterized by measurement of surface resistivity (ohm) according to ASTM D257 at 20° C. at a relative humidity of 65% under a continuous voltage of 100 V.
u) Waterproofness-breathability or permeability to water vapour: It is estimated according to Standard ASTM 96 E BW at 38° C. and 50% relative humidity on a film with a thickness of 25 μm.
v) Impact strength/bending test. The test is carried out in the following way. 80×10×4 mm bars are moulded by injection moulding in an ISO mould. The bar is bent rapidly by 180° at the injection gate, between the bar and the cluster, at the point where the thickness is reduced to approximately 1 mm. The number of clean breakages is subsequently measured over a series of 20 bars and is expressed as percentage of breakage.
The chemical resistance was also tested and showed a 100% resistance in ethanol and in acetone for the copolymer of Example 7.
These tests show that the copolymers of the present invention can be as transparent as the polyamides of the prior state of the art while having greater flexibility.
Example 32 constitutes a particular advantageous case. It is characterized in that the flexible ether units are chosen to be of highly hydrophilic nature, which confers antistatic and waterproof-breathable (that is to say, allowing the passage of water vapour but not of liquid water) properties on the composition. Furthermore, this composition can be additivated by third-party antistatic additives, in order to reinforce the overall antistatic effect, and by additives which make it possible to increase the blending compatibility with other polymers, it being possible for the copolymer, alone or thus additivated, subsequently to be specifically used as additive of another polymer or material in order to confer on it an improvement in its antistatic or waterproof-breathable properties. If the additivated polymer is transparent, then, advantageously, the PA monomers (and other additives) will be chosen so that the refractive index of our copolymer (optionally itself additivated) is very close to that of the additivated polymer.
TABLE 2
Comparative Examples 1-4 and Examples 6-10
Diamine
Diacid
(of the PA)
(of the PA)
% PE
Mn of
Mn of
Rise in
Tg
Delta
Example
Stage(s)
(1 mol)
(in mol)
PE
(weight)
the PA
the PE
viscosity
(° C.)
Hm(2)
Transparency
Comp. 1
1
BMACM
C14
0.00
0
yes
144
0
91
Comp. 2
1
PACM 20
C14
—
0.00
0
yes
125
0
90
Comp. 3
1
BMACM
C12
—
0.00
0
yes
152
0
91
Comp. 4
PA
PTMG
0.14
4000
650
yes
70
78
6/11/12
6
2
BMACM
C10
PTMG
0.12
5000
650
yes
131
4
86
7
2
BMACM
C10 (0.5),
PTMG
0.12
5000
650
yes
131
0
90
C12 (0.5)
8
2
BMACM
C14
PTMG
0.12
5000
650
yes
108
0
92
9
2
BMACM
C12(0.5),
PTMG
0.25
2000
650
yes
91
0
91
C14 (0.5)
10
2
BMACM
C12(0.5)-
PTMG
0.20
4000
1000
yes
112
0
86
C14 (0.5)
Flexural
Yield
Impact
modulus
Ross-
Elongation at
stress
strength/
Example
MFI
Opacity
(MPa)
α (alpha)
Flex
break (%)
(MPa)
Viscosity
Yellowing
bending
Comp. 1
6.5
12.4
1382
7.5
<10 000
190
51
1.17
40%
Comp. 2
18
9.7
1384
199
52
Comp. 3
6
10.1
1491
8.4
182
55
1.09
50%
Comp. 4
13
6
13
10.6
1455
10.2
202
50
1.18
0%
7
11
9.6
1377
8.9
221
48
1.21
0%
8
1190
260
43
1.11
13.7
0%
9
680
50 000
1.21
8.7
0%
10
970
290
35
1.21
0.25
0%
NB: the compositions of the “Diacid” column are given in moles. For example, Example 7 means: 12% by weight of PTMG with an Mn weight of 650 g and the remainder of PA, the latter having the composition: 1 mol of BMACM, 0.5 mol of C10 and 0.5 mol of C12. The weight of the PA is to be understood at within ±5% and it can be adjusted within this range in order to obtain an even better rise in viscosity.
TABLE 3 Diamine Diacid Rise in Ex. Stage(s) (of the PA) (of the PA) PE % PE MnPA MnPE viscosity Tg (° C.) by DSC Examples 11-26 and Comparative Example 17 11 1 BMACM C10 (0.5), PTMG 11.5 5000 650 yes 118 C12 (0.5) 12 1 BMACM C9 PTMG 11.5 5000 650 yes 129 13 1 BMACM C10 (0.5), PTMG 14 4000 650 yes 111 C12 (0.5) 14 1 BMACM C10 (0.5), PTMG 16.7 5000 1000 yes 127 C12 (0.5) 15 1 BMACM C10 (0.5), PTMG 17.8 3000 650 yes 100 C12 (0.5) 16 1 BMACM C10 (0.5), PTMG 17.8 3000 650 yes 108 C12 (0.5) Comp. 17 1 BMACM C6 PTMG 11.5 5000 650 no 110 18 1 BMACM C14 PTMG 11.5 5000 650 yes 107 19 1 BMACM C18 PTMG 13.9 4000 650 yes 80 20 1 BMACM C14 (0.5), PTMG 17.8 3000 650 yes 86 C18 (0.5) 21 I BMACM C14 (0.5), PTMG 17.8 3000 650 yes 88 C18 (0.5) 22 1 BMACM C14 (0.5), PTMG 24.5 2000 650 yes 75 C18 (0.5) 23 1 BMACM C14 (0.5), PTMG 33.3 2000 1000 yes 85 C18 (0.5) 24 1 BMACM C14 (0.5), Jeffamine 16.7 5000 1000 yes 122 C18 (0.5) 25 1 BMACM C14 (0.8), PTMG 16.7 5000 650 yes 111 C6(0.2) 26 1 BMACM C14 (0.85), PTMG 16.7 5000 650 yes 119 IA (0.15) Examples 27-32 27 1 BMACM C10(0.5), PTMG 0.2 4000 1000 yes 118 C14 (0.5) 28 1 BMACM C12 (0.5), PTMG 0.245 2000 650 yes 91 C14 (0.5) 29 1 BMACM C12 (0.5), PTMG 0.2 4000 1000 yes 104 C14 (0.5) 30 1 IPD C10 (0.5), PTMG 0.115 5000 650 yes 105 C14 (0.5) 31 1 PACM45 C14 PTMG 0.115 5000 650 yes 102 32 1 BMACM C14 (0.5), PEG 0.23 5000 1500 yes 85 C18 (0.5) Rigidity E' Tangent Delta Appearance, modulus at delta of Surface Permeability Ex. Hm(2) transparency 20° C. by DMA the DMA Viscosity Yellowing resistivity water vapour Examples 11-26 and Comparative Example 17 11 0 VG 1260 127 1.03 + 12 0 G 1.02 ++ 13 0 VG 1.02 + 14 0 G 0.93 0 15 0 VG 1125 120 0.88 / 16 0 VG 766 97 1.15 / Comp. 17 0 opaque / / 18 0 VG 1000 117 1.14 + 5 × 10 13 450 19 0 VG 0.88 + 20 0 VG 0.75 + 21 0 VG 1.15 + 22 0 VG 560 89 1.22 + 23 0 VG 410 111 1.34 + 24 0 VG 1.23 + 25 0 FG 0.74 + 26 0 VG 1130 123 0.87 ++ Examples 27-32 27 0 FG 886 121 1.33 + 28 0 VG 684 97 1.31 + 29 0 G 845 121 1.34 + 30 0 G 1.10 + 31 22 G 1.15 + 32 0 FG 4 × 10 10 7300
Application: Frames for Glasses
Frames for glasses were moulded (Frame 1 and Frame 2) using some of the copolymers produced above. The properties of the products obtained are presented in Table 4 below.
TABLE 4
Frame
1
2
Material (Example)
Comp. 3
Example 7
Temperature of the mould (° C.)
90
70
Temperature of the material (° C.)
290
275
Maintenance time (s)
6
4
Cooling time (s)
8
8
Cycle time (s)
15
13
Presence of bubbles
yes
no
Appearance
good, slight yellowing
Feel
soft
very soft
Tests were also carried out to evaluate the impact strength of the copolymers of the invention. 80×10×4 mm bars were moulded by injection moulding from materials of Table 1. Series of 16 bars were bent on clusters to measure the number of broken bars. A test was developed from clusters of 80×10×4 bars manufactured using some of the copolymers produced above: the bars are bent by 180° at their injection point (at the point where the thickness reduces in the form of an indentation) and the percentage of breakage is recorded. The results are presented in Table 5 below, in %.
TABLE 5
Bar
% of unbroken
Comp. 3
50 to 60%
Example 7
100%
These results show that the copolymers of the invention make it possible to simultaneously combine good control of the synthesis and good moulding conditions (lower temperature of the mould, no bubbles, good viscosity, and the like) with good optical properties (transparency) and good mechanical properties (very good flexibility and very good impact strength). | The present invention is a copolymer based on amide units and ether units, wherein the amide units being comprise a major portion of an equimolar combination of at least one diamine and at least one dicarboxylic acid, the diamine(s) is/are mainly cycloaliphatic and the dicarboxylic acid(s) is/are mainly linear and aliphatic, the amide units optionally comprise, but in a minor proportion, at least one other polyamide comonomer, the respective proportions of ether and amide unit monomers are selected in such a way that said copolymer is highly transparent to such an extent that the transmittance at 560 nm on a plate 2 mm thick is greater than 75%; the crystallinity of said copolymer is such that the enthalpy of fusion during the first heating of a ISO DSC (delta Hm(2)) is at least 30 J/g, where the mass is related to the number of amide units contained or of polyamide contained, which fusion corresponds to that of the amide units; and said copolymer has a glass transition temperature of at least 75° C. | 2 |
FIELD OF THE INVENTION
[0001] The present invention relates generally to information retrieval systems, and particularly to methods and systems for ranking results in category-based document searches.
BACKGROUND OF THE INVENTION
[0002] Text retrieval engines (TREs), or search engines, are used in a variety of web, intranet and desktop applications. In a typical information retrieval (IR) application, each document in a document collection is described by a set of representative keywords or phrases called “index terms.” The TRE searches the documents in the collection in response to a user query that comprises one or more of the index terms. The TRE typically returns a list of documents that best match the user query.
[0003] Most advanced information retrieval applications create an index of the documents in the collection that is to be searched. An example of such a system is the Guru search engine, which is described by Maarek and Smadja in “Full Text Indexing Based on Lexical Relations, an Application: Software Libraries,” Proceedings of the Twelfth Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, 1989, pages 198-206, which is incorporated herein by reference.
[0004] The index typically contains, for each document, a set of index terms that appear in the document with a score assigned to each index term. A typical scoring model used in many information retrieval systems is the TF-IDF formula, described by Salton and McGill in “An Introduction to Modern Information Retrieval,” McGraw-Hill, 1983, chapter 3, pages 52-63, which is incorporated herein by reference. The score of term T for document D depends on the term frequency of T in D (denoted TF), the length of document D, and the inverse of the number of documents containing term T in the collection (inverse document frequency, denoted IDF).
[0005] Document scores are typically used to rank the search results provided by the TRE in terms of their relevance to the query terms. For example, U.S. Patent Application Publication 2004/0002973 A1, whose disclosure is incorporated herein by reference, describes a method for automatically ranking database records by relevance to a given query. A similarity function is derived from data in the database and/or queries in a workload. The similarity function is then applied to a given query and used to rank the records.
[0006] In many information retrieval applications, documents are associated with one or more categories. The user query may request that the search be limited to one category or a combination of such categories. This search mode is referred to as “category-based search.” For example, U.S. Patent Application Publication 2003/0195877 Al, whose disclosure is incorporated herein by reference, describes a search engine that displays the results of a multiple-category search according to levels of relevance of the categories to a user search query.
[0007] Several publications propose methods for performing category-based searches. For example, U.S. Pat. No. 5,826,260, whose disclosure is incorporated herein by reference, describes an information retrieval system that analyzes a user query and presents a “hit list” of documents to the user. The presented hit list displays an overall rank of a document and the contribution of each query element to the overall rank. The user can then reorder the hit list by prioritizing the contribution of individual query elements to override the overall rank, and by assigning additional weights to those contributions.
[0008] Another approach for category-based searching is described by Glover et al. in “Improving Category Specific Web Search by Learning Query Modifications,” IEEE Symposium on Applications and the Internet (SAINT 2001), San Diego, Calif., January 2001, pages 23-31, which is incorporated herein by reference. The authors describe a system that recognizes web pages of a specific category. The system learns modifications to queries that bias results toward documents in that category. Extra words or phrases are added to a user query in order to increase the likelihood that results of the desired category are ranked near the top.
[0009] In some applications, a document collection is divided into several sub-collections, and a search is defined over several such sub-collections. For example, U.S. Pat. No. 6,795,820, whose disclosure is incorporated herein by reference, describes a meta-search method conducted across multiple document collections. A multi-phase approach is employed, in which local and global statistics are dynamically exchanged between local search engines and the meta-search engine in response to a user query. The meta-search engine merges results from the individual search engines, to produce a single list of ranked results for the user.
SUMMARY OF THE INVENTION
[0010] Many conventional scoring models adjust the score assigned to a particular index term based on document frequency statistics (i.e., the number of documents in the collection that contain this index term, denoted DF). Scoring models based on the TF-IDF formula cited above are an example for such models. Using these scoring models, an index term will typically receive a lower score if it appears in many documents in the collection. Conversely, a term will receive a higher score if there are fewer documents in the collection that contain it. As a result, the TRE will rank documents that contain rare index terms higher than documents containing common terms. The logic behind this statistical adjustment is that frequently-occurring terms are assumed to be less descriptive of the user query, and therefore less relevant.
[0011] When a user limits a search query to a specific category of the collection, the user expects to see results that are ranked according to their relevance within the particular category. When conducting category-based searches, however, adjusting scores based on global statistics (i.e., statistics that were calculated over the entire document collection) may cause improper ranking of the search results. This improper ranking may cause highly relevant documents to be ranked low in the list of search results, or to be discarded from the list altogether.
[0012] A theoretical “naive” solution to this problem is for the IR system to maintain a separate index for each category. Each such index would have term statistics that are calculated only within the category. (Category-dependent statistics are also referred to as “local statistics.”) This solution is not feasible in most practical cases for several reasons: The number of categories may be very large, resulting in unreasonable memory requirements for storing the multiple indices. Category definitions and contents may change with time. Furthermore, a query may be defined over a category or combination of categories (referred to as a “category restriction”), in which case the number of required indices grows combinatorically with the number of categories. The computational complexity required for pre-calculating the local statistics of all index-terms within all category restrictions is prohibitive.
[0013] There is, therefore, motivation for providing a category-based ranking method that uses a single, comprehensive index. From the user point of view, such a method should ideally rank documents as if the search considered only local term statistics, within the category restriction specified by the query.
[0014] Embodiments of the present invention provide such improved methods and systems for category-based searching. According to a disclosed method, histograms are calculated and stored for all index terms and categories in a document collection. When a user query requests a search within a specific category restriction, the term histograms and category histograms are used to calculate localized term histograms, so as to approximate the local statistics of the index terms within the specified category restriction. These localized term histograms are used to estimate the document frequency (DF) of each index term in the query within the category restriction. The TRE then ranks the documents in the category restriction according to the estimated DF in order to produce a properly ranked list.
[0015] In a disclosed embodiment, the user query may specify “dynamic category restrictions,” or category definitions that were not represented as histograms in advance. To deal with this sort of query, the TRE is first invoked so as to identify documents that belong to this new category definition. New category histograms are produced accordingly, and the local statistics of index terms within the dynamic category restriction are then estimated.
[0016] In other embodiments, the histogram-based method is used to perform searching over a document collection sub-divided into multiple sub-collections.
[0017] There is therefore provided, in accordance with an embodiment of the present invention, a method for searching a document collection that includes a plurality of documents that are respectively associated with one or more categories and contain terms, the method including:
[0018] providing an index of the terms indicating the documents in which the terms appear;
[0019] estimating a first statistical distribution of each of at least some of the terms in the index and a second statistical distribution of each of at least some of the categories over the documents in the collection;
[0020] accepting a query including one or more of the terms and a category restriction referring to at least one of the categories;
[0021] operating on the first estimated statistical distribution of at least one of the terms in the query using the second estimated statistical distribution of the at least one of the categories, responsively to the category restriction, so as to produce a modified term distribution; and
[0022] applying the query to the index so as to return a response in which occurrences of the at least one of the terms are scored responsively to the modified term distribution.
[0023] In a disclosed embodiment, estimating the first statistical distribution includes constructing term histograms of the at least some of the terms in the index, estimating the second statistical distribution includes constructing category histograms of the at least some of the categories, and constructing the term and category histograms includes mapping the documents in the collection to bins of the histograms. Additionally or alternatively, constructing the term and category histograms includes, when a document is added to or deleted from the collection, incrementally updating the term and category histograms responsively to the added or deleted document.
[0024] In another embodiment, operating on the first estimated statistical distribution includes determining a category restriction histogram based on the category histogram of the at least one of the categories responsively to the category restriction, and multiplying the category restriction histogram by the term histogram of the at least one of the terms in the query so as to produce a localized term histogram. Additionally or alternatively, when the category restriction refers to two or more of the categories linked by a Boolean expression, determining the category restriction histogram includes combining the category histograms of the two or more of the categories based on the Boolean expression.
[0025] In yet another embodiment, applying the query includes determining a local document frequency (DF) based on the modified term distribution, and processing the query using the local DF.
[0026] In still another embodiment, the response includes a list of the documents, and applying the query includes ordering the list responsively to the modified term distribution.
[0027] In a disclosed embodiment, estimating the second statistical distribution includes querying a text retrieval engine (TRE) responsively to the category restriction, so as to obtain a list of documents in the collection that are associated with the category restriction.
[0028] In another disclosed embodiment, the categories include sub-collections of the document collection, the category restriction refers to at least one of the sub-collections, and operating on the first estimated statistical distribution includes producing the modified term distribution so as to describe the first statistical distribution within the sub-collections referred to by the category restriction.
[0029] There is additionally provided, in accordance with an embodiment of the present invention, apparatus for searching a document collection, including:
[0030] a memory, which is arranged to store a plurality of documents that are respectively associated with one or more categories and contain terms;
[0031] a search processor, which is arranged to provide an index of the terms indicating the documents in which the terms appear, to estimate a first statistical distribution of each of at least some of the terms in the index and a second statistical distribution of each of at least some of the categories over the documents in the collection, to accept a query including one or more of the terms and a category restriction referring to at least one of the categories, to operate on the first estimated statistical distribution of at least one of the terms in the query using the second estimated statistical distribution of the at least one of the categories, responsively to the category restriction, so as to produce a modified term distribution, and to apply the query to the index so as to return a response in which occurrences of the at least one of the terms are scored responsively to the modified term distribution.
[0032] There is further provided, in accordance with an embodiment of the present invention, a computer software product for searching a document collection that includes a plurality of documents that are respectively associated with one or more categories and contain terms, the product including a computer-readable medium, in which program instructions are stored, which instructions, when read by the computer, cause the computer to store an index of the terms indicating the documents in which the terms appear, to estimate a first statistical distribution of each of at least some of the terms in the index and a second statistical distribution of each of at least some of the categories over the documents in the collection, to accept a query including one or more of the terms and a category restriction referring to at least one of the categories, to operate on the first estimated statistical distribution of at least one of the terms in the query using the second estimated statistical distribution of the at least one of the categories, responsively to the category restriction, so as to produce a modified term distribution, and to apply the query to the index so as to return a response in which occurrences of the at least one of the terms are scored responsively to the modified term distribution.
[0033] The present invention will be more fully understood from the following detailed description of the embodiments thereof, taken together with the drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 is a block diagram that schematically illustrates a system for searching a document collection, in accordance with an embodiment of the present invention;
[0035] FIG. 2 is a diagram that schematically illustrates a document collection divided into categories, in accordance with an embodiment of the present invention;
[0036] FIGS. 3A-3C are diagrams that schematically illustrate equi-width histograms, in accordance with an embodiment of the present invention;
[0037] FIG. 4 is a flow chart that schematically illustrates a method for document searching, in accordance with an embodiment of the present invention; and
[0038] FIG. 5 is a plot that schematically illustrates document frequency estimation errors, in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF EMBODIMENTS
[0039] System Description
[0040] FIG. 1 is a block diagram that schematically illustrates a system 20 for searching a document collection 21 , in accordance with an embodiment of the present invention. A client 22 issues a user query to a search processor 24 , for searching the document collection. The processor comprises a TRE that performs the search according to methods described below. Typically, the processor produces a list of documents, ranked in terms of their relevance to the query. The list of documents is returned to client 22 .
[0041] Typically, processor 24 comprises a general-purpose computer, which is programmed in software to carry out the functions described herein. The software may be downloaded to the computer in electronic form, over a network, for example, or it may alternatively be supplied to the computer on tangible media, such as CD-ROM. The processor may be a standalone unit, or it may alternatively be integrated with other computing equipment of system 20 .
[0042] In addition to text documents, the methods described hereinbelow may also be applied to data files, records stored in a database, or other types of data items stored in a data structure. Adaptation of the methods to apply to such data items is straightforward and is considered to be within the scope of the present invention. In the context of the present patent application and in the claims, all these types of data items are referred to collectively as “documents,” and the data structure is referred to as a “document collection.”
[0043] Categories and Category Restrictions
[0044] In many applications, the document collection is divided into categories. Each document in the collection is associated with one or more categories. For example, categories may comprise knowledge domains, such as philosophy, medicine or law, or specific fields within these domains. As another example, categories may comprise departments in an organization, wherein each document is associated with the department that created it. In another example, categories may comprise user-names, wherein each document is associated with the user who owns it, such as in a mail-search application. Documents may also be categorized by one of their attributes. For example, a user may query for documents having a certain size range or date range.
[0045] FIG. 2 is a diagram that schematically illustrates document collection 21 divided into categories 30 , in accordance with an embodiment of the present invention. In the example shown in FIG. 2 , for the sake of simplicity, the document collection comprises three categories denoted C 1 , C 2 and C 3 . The three categories have some overlapping regions, demonstrating that some documents may belong to two or more categories simultaneously.
[0046] Different combinations of categories can be defined using Boolean expressions over the categories. For example, shaded area 36 in FIG. 2 is defined by the Boolean expression C 3 ∪(C 1 ∩C 2 ), wherein ∪ denotes the set union operator and ∩ denotes the set intersection operator. A Boolean expression defining a combination of categories is referred to as a “category restriction” (which may also include a single category). For example, assume that document collection 21 comprises a collection of text documents. Assume that category C 1 comprises all Microsoft® Word files, category C 2 comprises all documents larger that 1 MB, and category C 3 comprises all files created before Jan. 1, 2000. The category restriction C 3 ∪(C 1 ∩C 2 ) comprises all Microsoft Word documents that are larger than 1 MB, and all documents in the collection that were created before Jan. 1, 2000.
[0047] As noted above, when searching within category restrictions, adjusting scores based on global statistics may cause improper ranking of the search results. The following example demonstrates this improper ranking effect. Consider a computer organization having a large collection of documents. The organization includes a small accounting division that owns a small subset of the documents in the collection. Typically, the vast majority of the organization's documents will contain the index term “computer.” Only a small number of documents will contain the index term “costs.” On the other hand, within the category of documents that belong to the accounting division, most documents will contain the index term “costs,” and only a few will contain the index term “computer.” In other words, the global and local document frequencies of the index terms “computer” and “costs” are totally different. The following table shows the term statistics of this example:
Documents Documents Number of containing containing Category documents “computer” “costs” Entire 100,000 90,000 1,000 collection Accounting 500 10 400
[0048] Now assume that a user from the accounting division issues a query for “computer costs” within the “accounting” category. If global statistics are used to rank the results, the term “costs” has a much lower document frequency than “computer,” causing documents with many occurrences of “costs” to be ranked as top results. On the other hand, if local statistics are used, the term “computer,” having far fewer occurrences than “costs,” will now dominate the top results. Since “costs” is a very common index term within the accounting category, it should not be considered a good measure of relevance to this particular query. The above example shows that using global statistics in a category-based search may cause the most highly-relevant documents to be ranked too low. When the TRE uses “result pruning” (discarding of low-ranking documents from the list of search results) these low-ranked documents may not be retrieved at all.
[0049] Estimation of Local Statistics Using Histograms
[0050] The method described below provides a solution to the improper ranking by estimating the local document frequency (DF) within a given category restriction, using equi-width histograms. The method still maintains only a single index and a single set of global term statistics.
[0051] Histograms are a commonly-used technique for approximating large data distributions and joint distributions by grouping data items into buckets. Histograms offer a way to approximate large distributions, while requiring only modest memory space and computational complexity. For example, Piatetsky-Shapiro and Connell describe one application of histograms in “Accurate Estimation of the Number of Tuples Satisfying a Condition,” Proceedings of the 1984 International Conference on Management of Data (ACM SIGMOD), Boston, Mass., pages 256-276. Another application of histograms is described by Chen et al., in “Selectivity Estimation for Boolean Queries,” Proceedings of the 2000 ACM Symposium on Principles of Database Systems, Dallas, Tex., pages 216-225. Both papers are incorporated herein by reference.
[0052] For implementing the disclosed method, carried out by search processor 24 , each document in collection 21 is assigned an identification number denoted DOC_ID. The document collection is partitioned into n equal-size, disjoint subsets called buckets. The buckets are denoted bi, i=1, . . . , n. Typical values for n are in the range of 10-100, although other values are also feasible in some applications.
[0053] A predetermined mapping function assigns each document to a particular bucket. (In other words, the mapping function maps DOC_IDs to bucket numbers.) In some embodiments, the mapping function comprises a “K-means” clustering algorithm. This algorithm divides a set of objects into K distinct subsets according to their similarity. A detailed description of the K-means algorithm is given by Agarwal et al., in “Exact and Approximation Algorithms for Clustering,” Proceedings of the Ninth Annual ACM-SIAM Symposium on Discrete Algorithms, San Francisco, Calif., Jan. 25-27, 1998, pages 658-667, which is incorporated herein by reference. Alternatively, any other suitable mapping function that provides an approximately even distribution of DOC_IDs to bucket numbers can be used. (Generally speaking, however, random mapping of DOC_IDs to bucket numbers is not desirable, since it is likely to yield flat histograms.)
[0054] Search processor 24 represents the statistical distributions of the different index terms and categories using equi-width histograms. For each index term T, search processor 24 maintains an equi-width histogram comprising n bins, corresponding to the n buckets. Each bin denoted hi of the histogram gives the relative number of documents in bucket bi (i=1, . . . , n) that contain the term T. The search processor maintains a similar histogram for each defined category. The histogram of a category Ck comprises n bins hi that give the relative number of documents in bucket bi (i=1, . . . , n) that belong to category Ck.
[0055] In one embodiment, the term histograms and category histograms are updated incrementally when documents are added to or deleted from the document collection. When a new document is added to the collection, the search processor maps it to one of the buckets, denoted bk, using the mapping function. The processor then increments the kth bin of the term histograms of all index terms that appear in the newly-added document. The processor similarly increments the kth bin of the category histograms of all categories associated with the newly-added document. When a document, originally mapped to the kth bucket, is deleted from the collection, the processor performs a similar updating process. The processor decrements the kth bins of all relevant term and category histograms.
[0056] FIGS. 3A-3C are diagrams that schematically illustrate equi-width histograms, in accordance with an embodiment of the present invention. In this example, the document collection is partitioned into 10 buckets (n=10). FIG. 3A shows a term histogram 40 that corresponds to an index term denoted T 1 . Term histogram 40 can be viewed as an estimate of the global statistics of term T 1 , partitioned into buckets. In other words, the value of the ith bin of histogram 40 is an estimate of the probability that a document that belongs to bucket bi will contain term T 1 .
[0057] FIG. 3B shows a category histogram 42 that corresponds to a category denoted C 1 . As defined above, the ith bin of category histogram 42 gives the relative number of documents in bucket bi that belong to category C 1 . In other words, the value of the ith bin of histogram 42 is an estimate of the probability that a document that belongs to bucket bi will belong to category C 1 .
[0058] Since the same mapping function is used for constructing all the histograms in system 20 , respective bins in histograms 40 and 42 pertain to the same subset of documents. An estimate of the local statistics of term T 1 within category C 1 is produced by multiplying respective bins of histograms 40 and 42 .
[0059] FIG. 3C shows a localized term histogram 44 , produced by multiplying the respective bins of histograms 40 and 42 . Localized term histogram 44 can be viewed as an estimate of the local statistics of term T 1 within category C 1 , partitioned into buckets. In other words, the value of the ith bin of histogram 44 is an estimate of the probability that a document in bucket bi that belongs to category C 1 will contain term T 1 .
[0060] The estimated local document frequency DF of term T 1 within category C 1 is calculated by summing the n bins of localized term histogram 44 . The resulting DF value can be subsequently used by the TRE in estimating local statistics, as will be explained below.
[0061] In some embodiments, the DF estimation method described by FIGS. 3A-3C above is generalized to estimate DF within a category restriction that comprises a combination of several categories. As described above, a category restriction is represented by a Boolean expression over one or more categories. In order to estimate local statistics within a category restriction, the processor uses the histograms of the individual categories in the Boolean expression to produce a category histogram that represents the category restriction.
[0062] For example, consider two categories C 1 and C 2 that are represented by two histograms denoted H 1 ={x 1 , . . . , xn) and H 2 ={y 1 , . . . , yn}, respectively. The category restriction C 1 ∩C 2 is then represented by the histogram HC 1 ∩C 2 =H 1 ·H 2 ={x 1 ·y 1 , x 2 ·y 2 , . . . , xn·yn}, wherein xi and yi are the bins of histograms H 1 and H 2 , respectively. The values of xi and yi are assumed to represent probabilities, and therefore 0≦xi, yi≦1. Consider also a category restriction defined as {overscore ( C 1 )}, denoting the complement of category C 1 (i.e., all documents that do not belong to category C 1 ). The histogram of {overscore ( C 1 )} is given by {overscore ( H 1 )}={1-x 1 , 1-x 2 , . . . , 1-xn}. Since any Boolean function can be expressed in terms of intersection and complement operations, it is straightforward to produce a histogram that represents any category restriction using the histograms that represent the individual categories.
[0063] Although the embodiments described herein make use of equi-width histograms, the methods of the present invention may also be adapted for use with histograms of other types, in which the bins are not necessarily of equal widths.
[0064] The category restriction histogram is used by the search processor to estimate the local term statistics within the category restriction using the following method.
[0065] Document Searching Method
[0066] FIG. 4 is a flow chart that schematically illustrates a method for category-based searching within category restrictions, in accordance with an embodiment of the present invention.
[0067] The method begins with search processor 24 constructing a set of term histograms, at a term histogram construction step 60 . Each term histogram has the form of histogram 40 of FIG. 3A above. The processor may store the set of term histograms as part of the index of document collection 21 , or in a separate data structure. In one embodiment, the processor constructs a term histogram for every index term in the index. In an alternative embodiment, the processor constructs and stores histograms only for commonly-used index terms. Histograms for rarely-used index terms are constructed only when the processor accepts a query that comprises such terms. The classification of index terms as commonly-used or rarely-used may follow any suitable criteria.
[0068] The processor also constructs and stores a set of category histograms, at a category histogram construction step 62 . Each category histogram has the form of histogram 42 of FIG. 3B above. In one embodiment, the processor constructs a histogram for every defined category. In an alternative embodiment, the processor constructs and stores histograms only for commonly-used categories. Histograms for rarely-used categories are constructed only when the processor accepts a query that comprises such categories. Again, the classification of categories as commonly-used or rarely-used may follow any suitable criteria. (See also a discussion of “dynamic category restrictions” below.) The order of execution of steps 60 and 62 may be reversed if desired.
[0069] The search processor accepts a user query, at a query acceptance step 64 . The user query comprises one or more index terms that describe the documents to be searched. The query also typically comprises a category restriction definition that describes a category or combination of categories over which the search should be performed. In one embodiment, the category restriction is represented by a Boolean expression over one or more categories.
[0070] Having accepted the query, the processor constructs a category restriction histogram that represents the category restriction, at a restriction histogram construction step 66 . If the category restriction describes a single category to which the search should be restricted, the category restriction histogram has the same form as the category histogram of the category in question. Otherwise, the category restriction histogram may be constructed from the individual category histograms of the categories to which the category restriction refers. If the category restriction comprises rarely-used categories, for which pre-constructed category histograms may not exist, the processor constructs the necessary category histograms. (See also a discussion of “dynamic category restrictions” below.) Having retrieved or constructed the necessary category histograms, the processor uses these histograms to produce a category restriction histogram that represents the category restriction supplied in the user query. Calculation of the category restriction histogram is typically implemented using histogram intersection and complement operations, as described in the discussion of FIGS. 3A-3C above.
[0071] After calculating the category restriction histogram, the processor now constructs localized term histograms, at a localized construction step 68 . The processor calculates, for each index term in the user query, a localized term histogram that represents the local term statistics (i.e., a modified term distribution) of this index term within the category restriction. As explained above, each localized term histogram is produced by multiplying the respective bins of the term histogram and the category restriction histogram. The output of step 68 is a set of histograms that estimate the local statistics of each index term in the query within the category restriction.
[0072] The processor calculates the estimated local DF for each index term in the user query, at a DF estimation step 70 . As explained above, the estimated local DF of each index term within the category restriction is produced by summing the bins of the corresponding localized term histogram. The output of step 70 is a set of estimated local DF values, one DF value for each index term in the query. The estimated local DF values approximate the document frequency of the respective index term within the specified category restriction.
[0073] Finally, the processor ranks the documents that belong to the category restriction, at a ranking step 72 . The processor uses the set of estimated local DF values, representing the term occurrences within the category restriction, to rank the documents. In one embodiment, the processor applies a scoring model based on the TF-IDF formula for ranking the documents. Alternatively, any other suitable scoring model may be used. Typically, the method returns a response comprising a ranked list of documents. Since the ranking is based on the localized term statistics of the specified category restriction, and not on global term statistics of the entire document collection, the ranking of the search results is typically much closer to the ranking that would have been returned by a local search over the sub-collection identified by the category restriction.
[0074] Processing Dynamic Category Restrictions
[0075] In some embodiments, the category restriction in the user query comprises categories that cannot be (or are chosen not to be) defined in advance. For example, consider a catalog, in which every item is associated with a price. The user query restricts the search only to items whose price is within a given range. Another example is a query that restricts the search to documents created within a given time interval. (In this case document creation dates are treated as index terms.) Such category restrictions are referred to as “dynamic category restrictions.”
[0076] The search method described in FIG. 4 above can be generalized to the case of dynamic category restrictions. When the search processor executes restriction histogram construction step 66 , it calculates a category histogram representing the dynamic category restriction. In one embodiment, the processor queries the TRE in order to identify the set of documents that satisfy the dynamic restriction (for example, identifying the set of documents that were created within a specified time interval). Typically, the processor queries the TRE using Boolean queries. Boolean queries are usually more efficient to execute in comparison to free text queries. Subsequently, the processor calculates the category histogram that represents this document set, following the same method used for ordinary categories. From this stage, the method continues to follow the flow of FIG. 4 , as described above.
[0077] Searching Over Multiple Document Collections
[0078] In some practical cases, the document collection is sub-divided into several (not necessarily disjoint) sub-collections. This configuration is sometimes preferred for scalability or performance reasons. Each sub-collection comprises its own index. A search can be restricted to a combination of sub-collections. The methods described above can also be used to perform proper ranking when searching over a restricted set of sub-collections. It is assumed that the entire document collection uses a single set of DOC_IDs and a single mapping function that assigns documents to buckets.
[0079] In some embodiments, the user query specifies a search over a combination of sub-collections. In these embodiments, the processor estimates the local term statistics using a respective combination of term histograms from the different sub-indices. For example, when searching over the union of two sub-collections, the processor produces a localized term histogram for each index term in the query. This localized term histogram is produced by calculating the union of the two term histograms from the two sub-collections.
[0080] The processor then performs two separate searches in the two sub-indices using the respective localized term histograms. The processor merges the two sets of results, to produce a single set of documents with proper ranking. This ranking approximates the ranking which would have been returned by a “naive” search over an index corresponding to the union of the two sub-collections.
[0081] Simulation Results
[0082] The inventors have simulated the search method described in FIG. 4 above, in order to demonstrate and quantify the effectiveness of the disclosed method.
[0083] The simulation program chose at random a group of 100 index terms from the TREC collection (a collection comprising 500,000 text documents, as described in “Overview of the Seventh Text Retrieval Conference (TREC-7),” Proceedings of the Seventh Text Retrieval Conference (TREC-7), National Institute of Standards and Technology, 1999. Each simulation run picked two index terms from the group of 100 terms, and applied the method of FIG. 4 to estimate the number of documents that contain both index terms. (This test was chosen because measuring the size of the intersection between two sets is a highly-sensitive test. Since the intersection is typically much smaller than the sets themselves, the relative error is much larger.)
[0084] The simulation estimated the DF values of these index terms, according to the method of FIG. 4 . The estimated DF values were then compared with the actual DF values, for all possible combinations of term pairs (4950 pairs in total).
[0085] FIG. 5 is a plot that schematically illustrates document frequency estimation errors, in accordance with an embodiment of the present invention. A curve 80 shows the relative document frequency estimation error, as a function of the histogram size (i.e., the number of buckets). The error function used in the calculation is the “average absolute relative error” function described in the paper by Chen et al. cited above. As can be seen in the figure, the estimation error decreases with increasing histogram size. For histograms of 20 buckets and above, the error grows asymptotically small, indicating that the estimated DF values provide a good approximation of the actual values.
[0086] While the methods described hereinabove mainly addressed category-based retrieving of documents in a document collection, these methods can also be used for other applications that use statistical ranking of data items that are associated with categories.
[0087] It will thus be appreciated that the embodiments described above are cited by way of example, and that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and sub-combinations of the various features described hereinabove, as well as variations and modifications thereof which would occur to persons skilled in the art upon reading the foregoing description and which are not disclosed in the prior art. | A method for searching a document collection includes providing an index of terms indicating the documents in which the terms appear. A first statistical distribution of each of at least some of the terms in the index and a second statistical distribution of each of at least some of the categories are estimated a over the documents in the collection. A query including one or more of the terms and a category restriction referring to at least one of the categories is accepted. A modified term distribution is produced by operating on the first estimated statistical distribution of at least one of the terms in the query using the second estimated statistical distribution of the at least one of the categories, responsively to the category restriction. The query is applied to the index so as to return a response, in which occurrences of the at least one of the terms are scored responsively to the modified term distribution. | 8 |
BACKGROUND OF THE INVENTION
The present invention relates to a tracer unit particularly suitable for use with measuring machines, comprising a plurality of tracer tools which generate an electric output signal for signalling a position of contact of the tracer tool with a workpiece, said position being signalled, in accordance with the type of tracer tool, either when the tracer tool leaves the position of equilibrium or when it passes through a position of equilibrium.
There are known individual tracer tools, both omnidirectional and bidimensional or unidimensional, i.e., in which the tip of the tracer tool is movable along three, or two, or one axis. For example, the tracer tools described in U.S. Pat. No. 4,023,045 of the same Applicant are electronic omnidirectional tracers of the type in which en electric signal is generated when the tracer leaves the position of equilibrium. Other tracer tools, bidimensional and unidimensional, are known for instance from the U.S. Pat. No. 3,727,119 and from the British patent specification No. 855,676.
When carrying out measurings on outer surfaces or in inner regions where it is possible for the whole column of the machine to be penetrated along its axis (axis z), or when utilizing bidimensional or unidimensional tracers, it is sometimes necessary to use tracer tools whose axis is disposed in successive stages along different directions. Therefore, it is necessary to detach the individual tracer tool from the head of the measuring machine and to substitute it or to dispose it in another position.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a tracer unit comprising a plurality of tracer tools of the type mentioned hereinabove, which will allow carrying out, quickly and in a simple way, measurings on outer surfaces or in inner regions into which a penetration of the tracer unit is possible, without having to substitute the individual tracer tools for disposing them in different positions.
According to the present invention there is provided a tracer unit for use with measuring machines, comprising: a plurality of tracer tools, each of which is provided with a rod arranged to come into contact with a surface to be scanned, a movable body connected to said rod, a fixed body, first means which supply a first signal either when said movable body leaves the position of equilibrium relative to said fixed body or when said movable body passes through a determined position relative to said fixed body; and second means arranged to indicate from which the various tracer tools said first signal is originated.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention some embodiments thereof, given by way of a non limitative examples, will now be described with reference to the accompanying drawings, in which:
FIG. 1 is a side elevational view of a tracer unit according to the principles of the present invention;
FIG. 2 is a top view, sectioned along line II--II, of the tracer unit shown in FIG. 1;
FIG. 3 is a partially sectioned side elevational view of the tracer unit of FIG. 1, with a cable for connection to a measuring machine;
FIG. 4 is a top view, sectioned along line IV--IV, of the outer body of the tracer unit shown in FIG. 3;
FIG. 5 is a partial side elevational view, partially sectioned along line V--V, of the tracer unit shown in FIG. 2;
FIGS. 6, 7 and 8 are, respectively, a top view of the fixed body and a bottom and a top view of the movable body of the cutout device of each of the individual tracer tools included in the unit shown in FIG. 1;
FIGS. 9 and 10 are, respectively, a wiring diagram of the tracer unit according to the present invention and a wiring diagram of the cutout device of each of the individual tracer tools included in the unit shown in FIG. 1;
FIGS. 11 and 12 are part setioned side elevational views of parts of two further different embodiments of the tracer unit according to the present invention; and
FIG. 13 is a block diagram of a portion of the electric circuit of the individual tracers included in the units shown in FIGS. 11 and 12.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to Figures from 1 to 5, the tracer unit of the present invention comprises a container body 1 and an upper cover 2 fixed by means of four screws 8 (FIGS. 2 and 5). Container 1 has at its bottom end a plane surface 4 and at its upper end four chamfered plane portions 6 equispaced by 90° from each other. Formed centrally on the cover 2 and extending upwards is a cylindrical tang 11 having a ground outer surface and being provided with an inner thread, which is mechanically connected in a well-know manner to a head of a measuring machine (not shown). The plane bottom surface 4 and the four chamfered plane portions 6 of the body 1 have each a through hole 12 (FIG. 4), and such five holes 12 are coaxial with five recesses 13 formed inside the container 1. In a central region of the body 1 there is fixed by means of four screws 15 (FIGS. 4 and 5) a block 14 substantially cubic in shape. Glued onto each of, five sides of the block 14 are three posts 17 arranged in the respective recess 13 and equispaced by 120°. Connected to the lower end of the posts 17 by means of screws 18 is a fixed block 21 (FIGS. 3 and 6) in the shape of an annular crown with a frusto-conical central through hole 22. On the upper portion of said block 21, whose surface is rendered insulating, there is fixed an insulating cage 23 which is provided with three holes 24 for the passage of the posts 17 and from which there are projecting a metal block 207 having a plane surface, a pair of metal balls 208 and three metal balls 209, according to the configuration described in U.S. Pat. No. 4,023,045. The cage 23 carries also a printed circuit with an input connection 212 disposed between the outer edge of the cage 23 and one of the balls 208, a connection 213 disposed between the other ball 208 and the block 207, and three output connections 214 each of which is disposed between one of the balls 209 and the outer edge of the cage 23. Disposed on the fixed block 21 is a movable block 27 provided with three outer oblique grooves 28 (FIG. 8) disposed at 120°, which allow the passage of the posts 17. Fixed on the lower surface of said movable block 27, which is made to be insulating, is an insulating cage 221, from which project a pin 218 and two balls 219 and 220, according to the configuration already described in U.S. Pat. No. 4,023,045. This cage 221 too carries a printed circuit including a connection 222 disposed between the balls 219 and 220. In an axial threaded hole 33 of the movable block 27 there is screwed the end of a measuring rod 35 which comes out from the container body 1. Bearing in the upper zone of the movable block 27 is a cylindrical spring 37 whose other end bears against an adjusting screw 38 which is disposed in a threaded seating 41 formed in the central block 14.
Between the central block 14 and the respective fixed block 21, in each of the five recesses 13, there is disposed an annular cylindrical element 42 which carries a printed circuit whose terminals are connected to the input connection 212 and to the three output connections 214 of the cage 23. Cage 23 and cage 221 provide electric connections between the various elements (balls, blocks and pin) of the blocks 21 and 27, so as to define six switches connected in series and in parallel, which may be compared to a unitary cutout device arranged to supply a signal at the opening of anyone of said six switches. Referring to FIG. 10, said cutout device, indicated generally by reference numeral 150, is formed by the input connection 212 which arrives at the series of two switsches 160 and 161 provided by means of the two balls 208 cooperating with the pin 218. Switch 161 is connected, through the connection 213, to a switch 162 formed by the block 207 and the ball 219. The switch 162 is in its turn connected through the connection 222 to three switches 163 formed by the ball 220 and one of the three balls 209 respectively. Said three switches 163 are connected, by means of connections 43, to a logic OR gate 165 which is connected to a printed circuit 44 housed in the container 1 (FIG. 4). Connected to said printed circuit 44, which forms an intermediate connection element, are the connections 43 pertaining to the five tracer tools housed within the five recesses 13, as well as the connection wires from four signal lamps 45 disposed in the four chamfered plane portions 6. Said printed circuit 44 is connected through five connection wires 46, which pass through a central opening 47 of the cover 2, to the five lower contacts of a double electrical plug 48. Plug 48 is fixed by means of two pins 51 (FIG. 2) to a block 53 which is disposed inside the tang 11 and is positioned by means of a threaded locking ring 53 screwed into the threaded inner opening of the tang 11. Vertically screwed into the block 52 two centering pins 54 which project with two portions, one of which has a larger cross-section and the other one has a reduced cross-section. Insertable into the interior of the tang 11 (FIG. 3) is a connecting block 55 connected by means of a cable 56 to a union 57 which provides the electrical connection to the measuring machine. Disposed in the lower portion of the connecting block 55 are an electric plug 63 for connection to the double plug 48, and two seatings 64 for lodging therein the two centering pins 54.
The electric circuits of the tracer unit of the present invention are shown in FIG. 9 in which there is diagrammatically shown, as unitary cutout device, the switch 150 formed by the assembly of the six switches constituted by balls 208, 209, 219 and 220, pin 218 and block 207, for each of the five tracer tools forming the tracer unit of the present invention. Reference numeral 70 indicates a supply cable having a negative voltage, for instance of -12 volts, which arrives at a terminal of a switch 71 pertaining to the tracer tool whose measuring rod 35 projects from the lower plane surface 4. The other terminal of the switch 71 is connected to input terminals of two switches 72 and 73 pertaining to two tracer tools whose measuring rods 35 project from two orthogonal portions 6. The outputs of the switches 72 and 73 arrive at the inputs of other two switches 74 and 75 respectively which pertain to tracer tools whose measuring rods 35 project from portions 6 which are parallel respectively to the portions 6 of the rods 35 of the corresponding series switch 72 or 73. The output terminals of the switches 74 and 75 are connected by connections 76 and 77 to impedance adaptor blocks 80 and 81, through resistore 78 in series and resistors 79 branched from a supply source having a voltage +V, conveniently of +5 Volts. The outputs of the two blocks 80 and 81, which are apt to supply in output a signal at logic level, arrive at a logic adder circuit 82 of the type OR, whose output arrives at the inputs which are respectively complementary of two memory circuits 83 and 84, and at an output connection 86. The circuits 83 and 84, which conveniently comprise monostable multivibrators, are arranged to be activated on mutually opposite wave fronts, do not accept successive signals of the same type for a predetermined period of time, and are each provided with an output connection 87 arranged to lock for a pre-established period of time the operation of the other circuit. The output of the circuit 83 transmits, through a connection 88, a measuring signal to the measuring machine.
The connections of the switches 72, 74 and 73, 75 respectively are connected to the anodes of two diodes 90 and 91 whose cathodes are connected, through a resistor 92, to the connection 70 and, directly, to an impedance adaptor block 93. The outputs of the adaptor blocks 80, 81 and 93 arrive at the input of a memory circuit 94 at which arrives also, as consent signal, the output of the circuit 83; said circuit 94 supplies the output signals to the measuring machine. The outputs of the blocks 80, 81 and 93 arrive also at the inputs of a decoder circuit 95 which receives also the output of the OR circuit 82; circuit 95 supplies control signals to a visualizer 96 having seven segments, which is disposed inside the union 57 (FIG. 3). The output of the logic OR circuit 82 arrives also, as consent signal, to a gate circuit 99, at which arrives a signal from a generator 100 which generates square waves at low frequency, for example of 4 Hz. Originating from circuit 99 is an output connection 101 which feeds the four signal lamps which are connected to the connection 70. The circuit shown in FIG. 9 is included in two dashed portions 103 and 104 respectively, the first of which is disposed inside the container 1 and on the printed circuit 44, whilst the second is disposed inside the union 57. The connections between said portions 103 and 104 is obtained by means of five connection wires formed by the wires 46, the five contact plugs 48 and 63 and the cable 56 (FIG. 3).
The operation of the tracer unit described hereinabove, provided by the present invention, is as follows.
When the ends of each of the five measuring rods 35 are not in contact with the surfaces to be scanned, they are disposed in the position of equilibrium determined by the movable block 27 being pressed against the fixed block 21, under the action of the spring 37; namely, the ball 220 bears on the three balls 209, the pin 218 bears on the two balls 208, and the ball 219 bears on the plane block 207. When the end of one of the measuring rods 35 meets the surface which has to be scanned, it inclines and/or lifts the movable block 27 and therefore at least one of the switches 160, 161, 162 and 163 shown in FIG. 10 is opened, so that the switching assembly 150 of the tracer tool results in being open in its generality and a signal of a different type, for instance of the type "1", is obtained at the output of the OR gate 165. Whatever tracer tools results in being involved in the measuring stage, and accordingly whatever switch 71, 72, 73, 74 or 75 opens, the potential of one of the connections 76 and 77, or of both of them, changes and a different signal, for example a signal of the type "1", is obtained at the output of the block 80 or 81 or of both of them. Accordingly, a signal of the type "1" is obtained at the output of the OR circuit 82 and consequently circuit 83 is activated, which circuit sends the measuring signal, along the connection 88, to the measuring machine and locks the circuit 84 for a convenient period of time, for example of 0.1 seconds, through the connection 87. Through the connection 86 there is obtained also the transmission of a signal to the machine, which signal informs about the open condition of any switch pertaining to one of the tracer tools. The signal of the type "1" at the output of the circuit 82 drives the circuit 99, allows the feeding of the low frequency signal from generator 100 to the four signal lamps 45 which are periodically lighted and extinguished so as to be visible by an operator in practically position of the tracer unit, in order to signal such open condition of the individual tool.
However, it is also necessary to send to the measuring machine an information about which of the five switches 71, 72, 73, 74, 75 pertaining to the five tracer tools is open. Such information is transmitted through the outputs of the blocks 80, 81 and 93 whose output logic level combination changes as a function of the switch which has been opened. In fact, the opening of the switch 71 causes a change of the level at the output of the blocks 80 and 81. The opening of the switches 72 or 74 causes a change of the level at the output of the block 80, whilst the opening of the switch 73 or 75 causes a change of the level at the output of the block 81. The identification of the opening of the switch 72 or 74, as well as the identification of the opening of the switch 73 or 75 takes place on the basis of the variation of logic level of the signal at the output of the block 93. Therefore, the combination of the signals at logic levels "0" and "1" at the output of the blocks 80, 81 and 93, which identifies as a number in binary form the tool which has moved away from the position of equilibrium, and which is present at the inputs of the memory circuit 94, is memorized, by means of the consent of the of the signal taken from the output of the circuit 83 and present, as explained above, when any one of the switches 71, 72, 73, 74 or 75 opens. Therefore, at the outputs of the circuit 94 there becomes present the number in binary form which identifies the tool which has moved away from the position of equilibrium, and this information, which is supplied to the machine, will be utilized by the machine itself at the right moment. The combination of the signals at logic levels at the outputs of the blocks 80, 81 and 93, which identifies the operated tool as a number in binary form, are decoded by the decoder circuit 95, under the consent signal of the type "1" at the output of the circuit 82, for driving the inputs of the visualizer 96 of the "7 segments type", which therefore gives the indication of a digit in decimal form corresponding to the number of the tool which has moved from the position of equilibrium, and such indication is visible to the operator, on the union 58. Therefore, when one of the tools moves away from the position of equilibrium, there is a general indication of this condition, in the form of a signal present on the connection 86 and sent to the machine, and in a visible form through the periodic lighting and extinguishing of all the lamps 45, and moreover there is an indication of which of the various tools has been moved, in the form of a signal combination present at the output of the circuit 94 and available to the machine, and in a visible form through the indication of a corresponding digit in decimal form on the visualizer 96.
Successively, when the tracer tool returns to the position of equilibrium, under the action of the spring 37, the switching assembly closes and cosequently a signal of the type "0" is obtained at the output of the circuit 82. Thus, circuit 84 is activated and locks the operation of the circuit 83 for a period of time of, for example, 0.1 seconds. In such condition of stable equilibrium there occurs also the transmission to the machine, along the output connection 86, of the signal informing about the condition of closure of the switches, and such signal of type "0", at the output of the circuit 82, by controlling the gate block 99 cuts off the supply to the signal lamps 45, which thus are extinguished again. In this way, whilst in the memory circuit 94 there remains memorized, as long as no new condition of opening of a switch arises again, the combination of signals at logic levels which identifies as a number in binary form the tool which has moved away from the position of equilibrium in fact no new consent signal arrives from the output of the circuit 83 to store in the circuit 94 the new input signals, the signal at the logic level "0" from the circuit 82 blocks the decoder circuit 95 which therefore does not supply the visualizer 96. Since the visualizer 96 gives no indication, it indicates that all the switches are closed.
The tracer unit according to the present invention, instead of being provided with three dimensional tracer tools, may be provided with unidimensional tracer tools, as shown in FIG. 11, or with bidimensional tracer tools, as shown in FIG. 12. In fact, the tracer unit shown in FIG. 11 has five unidimensional tracer tools 300, each of which is housed in the corresponding recess 13 inside the container 1. Each of said tracers 300 is provided with a cylindrical rod 301, to which there is connected a measuring tip 314 and on which there is inserted a cylindrical core 302 made of a magnetic material, for example soft iron. The rod 301 slides in two bushings 303 and 304, the first of which pertains to a hollow cylindrical body 305, whilst the second pertains to a hollow cylindrical body 306. The upper section of the body 306 is threaded and connected to the central block 14, whilst the body 305, which is disposed coaxially with the body 306 and outside of it, has an upper section 307 which is disposed around the lower end of body 306 and is fixed to the latter. Fixed to the upper end of the rod 301 is a cup 308 which abutting against the inner base surface of body 306 limits the external range of movement of the rod 301 and also serves as a support for a cylindrical spring 309, disposed inside body 306, which spring on the other side bears against a cap 310 fixed to the body 306. Disposed inside the body 305, coaxially with respect to the rod 301, is a cylindrical support 311 for a series of windings of a differential transformer (not shown), which windings are connected by connections wires 312 to the printed circuit 44. The differential transformer and the corresponding electric circuit of the tracer tool in FIG. 11, are represented in FIG. 13 in which an oscillator 320 having a high frequency, for example of 50 KHz, feeds a primary winding 321 of said differential transformer 322 which is disposed inside the cylindrical support 311. The differential transformer 322 has two secondary windings 323 which have one end connected together and the other end connected to the ends of a potentiometer 324. The common end of the secondary windings 323 and one end of the primary winding 321 are connected to earth. The slider of the potentiometer 324 is connected to the inverting input of a differential amplifier 325 which provides a threshold comparator with hysteresis, whose output arrives at an input 326 of a demodulator 327 which may conveniently be a bistable multivibrator. Oscillator 320 supplies also a generator 328 which generates clock signals and whose output is connected to another input 329 of the demodulator 327. The output of demodulator 327 is connected to a control input 330 of a block 331 which is provided with two outer terminals 332 and 333 and whose operation may be compared with that of a switch. Said block may for example comprise a field effect transistor.
The operation of the tracer unit of FIG. 11, with reference to the diagram of FIG. 13, is as follows. In rest conditions, when the ends of the five measuring tips 314 are not in contact with the surface which has to be scanned, because of the action of the spring 309 the rod 301 is in the position shown in the Figure, having a greater external extension, and the core 302 gives rise within the secondary windings 323 of the differential transformer 322 to waveforms such that, when taken from the potentiometer 324 and supplied, through the differential amplifier 325, to the input 326 of the demodulator 327 where they are compared with the signals present at the input 329 and coming from the generator 328, at the output of the demodulator 327 there is obtained a signal of constant value which arrives at the input 330 of the block 331 and maintains in a constant configuration (for example, closed) the equivalent switch between the terminals 332 and 333. When the end of one of the tips 314 meets the surface to be scanned, the rod 301 enters again the bodies 305 and 306, and the core 302, by passing through a position of electrical equilibrium relative to the position of the two secondary windings 323 of the differential transforme 322, gives rise in said secondary windings 323 to waveforms having a changed amplitude, which are such that the signal taken from the slider of the potentiometer 324 results in having an inverted phase, and by means of the demodulator 327 which compares the changed signal of the differential amplifier 325 with the always identical signal, at frequency of 50 MHz, of the generator 328, there is obtained at the output of the demodulator 327 a signal of different constant value which arrives at the input 330 of the block 331 and maintains in a complementary constant configuration (for example, open) the equivalent switch between the terminals 332 and 333. Since the behaviour of the block 331 may be compared to that of a switch, each block 331 pertaining to the five tracer tools of the tracer unit may be compared to one of the five switches 71, 72, 73, 74 and 75 of the diagram of FIG. 9, which thus has an operation identical to that described before, and there is obtained an identical indication as to which of the five tracer tools has carried out the scanning.
With reference to FIG. 13, all the various elements shown, except the differential transformer 322, may conveniently be disposed on the printed circuit 44.
The trcer unit of FIG. 12 has five bidimensional tracer tools 400, each of which is housed in the corresponding recess 13 inside the container 1. Each tracer tool 400 has a scanning rod 401 provided with a measuring tip 406 and connected by means of a pin 402 ot a supporting structure 403 formed by two side walls 404 connected to parts 405. Fixed to the rear end of the rod 401 is a core 407 made of a magnetic material, for example ferrite, whose heading surface has a contour extending along an arc of a circle. Confronting the core 407 is an E-shaped core 408 of magnetic material, such as ferrite, with the three arms which terminate, generally, according to the contour of an arch of a circle concentric with that of the core 407. On the central arm of the core 408 there is wound a primary winding of a differential transformer, whilst on the two side arms of the core 408 there are wound the secondary windings of the differential transformer. Said windings are not shown, but they correspond to the windings 321 and 323 of the differential transformer 322 shown in FIG. 13. The core 408 is fixed to a body 410, to which there is fixed also the upper portion of the supporting structure 403, and has also a portion 411 of circular cross-section, to which there is fixed a screw 412, and a cylindrical portion 413 which is inserted into a double cage bearing 414. Fixed to the upper end of the cylindrical portion 413 by means of a screw 416 is a body 417 having fixed thereto a pin 418 to which there is connected the end of a spring 419 whose other end is connected to a pin 421 fixed to a container 422 in the shape of a hollow cylinder, which encloses the cylindrical portion 413 and has an externally threaded upper portion 423 which is screwed onto the central block 14. Container 422 has at its lower portion a missing section extending along a sector of 90°, which limits to such value the angular movement of the screw 412.
The operation of the tracer unit shown in FIG. 12 which utilizes the same electric diagram shown in FIG. 13, is as follows. In the rest condition, in which the ends of the five measuring tips 406 are not in contact with the surface to be scanned, the rod 401 is inclined and the core 407, which is not in the position of equilibrium relative to the core 408, gives rise in the differential transformer 322 to such waveforms that the equivalent switch between terminals 332 and 333 of the block 331 remains in a constant condition (for example, closed). As the end of one the tips 406 meets the surface to be scanned, the rod 401 rotates about the pivot 402 and the core 407, by passing through a position of electrical equilibrium with respect to the core 408, gives rise in the differential transformer 322 to waveforms which are such that the equivalent switch between the terminals 332 and 333 of the block 331 assume the complementary condition (for example, closed). Therefore, the operation of the diagram of FIG. 9, for the tracer unit of FIG. 12, is identical to that already described for the tracer units of FIGS. 11 and 3. Said tracer tool 400 may carry out scannings in two directions orthogonal to one another; in fact, when rotating through 90° the supporting structure 403, which rotation is limited by the head of the screw 412 which abuts against the edges of the removed section at the lower end of the body 422, the rod 401 may rotate in a direction orthogonal to the former. The spring 419, which results in being stretched in the two positions of the supporting structure 403 which are orthogonal to one another, serves to maintain the stability of said two positions.
The tracer unit of the present invention, described hereinabove, has many advantages of being conveniently and reliably operable and of having a relatively simple constrution. First of all it allows carrying out scannings in different directions in a very simple way, without having to substitute the tracer tool or to change its position, by simply utilizing a different one of the five measuring rods.
Thus, the tracer unit of the present invention affords convenient combinations of tracer tools of the unidimensional or bidimensional type for obtaining performances which otherwise would be obtainable by means of tracer tools of the three dimensional type. The indication as to which of the five tracer tools has carried out the scanning and has therefore moved away from the position of equilibrium or has passed through the position of equilibrium, takes place at logic levels, and there are obtained a memorized signal which arrives at the measuring machine when required, and a signal which arrives at a visualizer device for the operator. The particular mutual connection of the switching assemblies pertaining to the five tracer tools allows having an electric connection between the tracer unit and the union of attachment to the machine, by means of only five connection wires, which allows a simple construction of the tracer unit.
Finally, it is obvious that modifications and variations of the embodiment described hereinabove might be possible both in the shape and arrangement of the various component parts, without departing from the scope of the present invention. For example, in a single tracer unit there may also be included single tracer tools of different types, i.e., three dimensional and/or bidimensional and/or unidimensional tracer tools.
The tracer unit of the present invention may also include tracer tools constructed in a different way with respect to each other; thus, it may also include tracer tools of the type described in the U.S. Pat. No. 3,727,119 or of the type described in the British patent specification No. 855,676. Also, it may include tracer tools of a known type different from those mentioned hereinabove, for example tracer tools in which the detection of the contact may be achieved through variation of a capacity, or by means of an emitter and a corresponding receiver for example of the photoelectric type or of the laser ray type, or also in another way. | A tracer unit for use with measuring machines is described.
The main feature of this tracer unit is to comprise a plurality of tracer tools, each of which is provided with a rod arranged to come into contact with a surface to be scanned, a movable body connected to said rod, a fixed body, first means which supply a first signal either when said movable body leaves the position of equilibrium relative to said fixed body or when said movable body passes through a determined position relative to said fixed body, and second means arranged to indicate from which of the various tracer tools said first signal is originated. | 8 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a method for the use of a lignan complex isolated from flaxseed for the treatment of atherosclerosis, e.g. reducing or preventing the development of hypercholesterolemic atherosclerosis, for reducing total cholesterol and for raising HDL-C in blood.
[0003] 2. Description of the Prior Art
[0004] Hypercholesterolemia is a major risk factor for atherosclerosis (narrowing of the artery due to deposition of fat in the arterial wall) and related occlusive vascular diseases such as heart attack, stroke and other peripheral vascular diseases. Heart disease is the number one killer. Hypercholesterolemic atherosclerosis has been reported to be associated with oxidative stress increase in levels of reactive oxygen species (ROS), production of ROS by polymorphonuclear leukocytes as assessed by chemiluminescence (PMNL-CL), and a decrease in the antioxidant reserve. Pretreatment with antioxidants (vitamin E, probucol, garlic, purpurogallin, secoisolariciresinol diglucoside) reverses the effects of hypercholesterolemia. Flaxseed which is a rich source of α-linolenic acid and richest source of plant lignans has been shown to be effective in reducing hypercholesterolemic atherosclerosis without lowering serum levels of cholesterol. Using flaxseed which has very low α-linolenic acid, has shown that antiatherogenic activity of flaxseed is not due to α-linolenic acid but may be due to lignan component of flaxmeal.
[0005] Presently the treatment of hypercholesterolemia and hypercholesterolemic atherosclerosis is to reduce hypercholesterolemia by using various lipid lowering agents such as bile acid sequestrant (cholestyramine, colestipol), nicotinic acid, HMG-CoA reductase inhibitor (lovastatin, provastatin, simvastatin, fluvastatin and atrovastatin) and gemfibrozil. Recently probucol which has both antioxidant and lipid lowering activity and vitamin E which has antioxidant activity have been used to prevent atherosclerosis and restenosis.
[0006] Drugs used for lowering serum lipids and for treatment of atherosclerosis (heart attack and stroke) have many side effects and are expensive. Fibric acid derivatives (gemfibrozil) produces gall stones, myopathy and hepatomegaly. Nicotinic acid produces gastrointestinal symptoms, flushing, hyperglycemia, hepatic dysfunction, elevated uric acid, abnormal glucose tolerance, and skin rash. Bile acid sequestrant (cholestyramine, colestipol) produces gastrointestinal symptoms, and high serum levels of very low density-lipoprotein (VLDL). HMG-CoA reductase inhibitors (statin) produce gastrointestinal symptoms, myopathy and hepatotoxicity. Probucol produces diarrhea and decreases the serum levels of HDL (good cholesterol).
[0007] Prasad, U.S. Pat. No. 5,846,944, describes the use of secoisolariciresinol diglucoside (SDG), isolated from flaxseed, for reducing hypercholesterolemic atheroscleorsis and reducing serum cholesterol. However, isolating SDG from flaxseed is a relatively expensive procedure.
[0008] In Westcott et al., U.S. Pat. No. 6,264,853, a new lignan complex is described which has been isolated from flaxseed. This lignan complex typically contains SDG (35%), cinnamic acid glycosides and hydroxymethyl glutaric acid. Only a simple procedure is required to isolate this lignan complex from flaxseed.
[0009] The purpose of the present invention is to provide a method of using the above lignan complex derived from flaxseed for medical purposes.
SUMMARY OF THE INVENTION
[0010] In accordance with this invention, it has been found that a lignan complex isolated from flaxseed can safely be administered to humans or non-human animals for the treatment of a variety of diseases. The complex and a method for its production are described in Westcott et al., U.S. Pat. No. 6,264,853, issued Jul. 24, 2001, and incorporated herein by reference. This complex is used in substantially pure form, e.g. a purity of at least 95%, and contains secoisolariciresinol diglucoside (SDG), cinnamic acid glucosides and hydroxymethyl glutaric acid. It typically has a nominal molecular weight in the range of about 30,000 to 100,000. The complex can be administered orally or intraperitoneally and has been found to be highly effective when administrated in a daily oral dosage of 20 to 60 mg per kg of body weight. The oral doses may conveniently be in the form of tablets or capsules and the complex may be used together with a variety of pharmaceutically acceptable diluents or carriers.
[0011] When administered to humans or non-human animals, the complex has been found to be highly effective for treating hypercholesterolemic atherosclerosis, as well as for reducing total cholesterol and raising HDL-C in blood. Thus, it is useful for the prevention and treatment of coronary artery disease, stroke and other peripheral vascular diseases.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] In the drawings which illustrate the present invention:
[0013] [0013]FIG. 1 is a graph showing sequential changes in serum triglyceride concentration for four different experimental groups;
[0014] [0014]FIG. 2 is a graph showing sequential changes in serum total cholesterol concentration of four different experimental groups;
[0015] [0015]FIG. 3 is a graph showing sequential changes in serum LDL-C concentration for four different experimental groups;
[0016] [0016]FIG. 4 is a graph showing sequential changes in serum HDL-C concentration for four different experimental groups;
[0017] [0017]FIG. 5 is a bar graph showing sequential changes in serum malondialdehyde (MDA) for four different experimental groups;
[0018] [0018]FIG. 6 is a bar graph showing aortic tissue malondialdehyde (MDA) concentration for four different experimental groups;
[0019] [0019]FIG. 7 is a bar graph showing aortic tissue chemiluminescence (Aortic-CL) for three different experimental groups;
[0020] [0020]FIG. 8 shows photographs of endothelial surfaces of aortas for four different experimental groups; and
[0021] [0021]FIG. 9 is a bar graph showing the extent of atherosclerotic plaques in the initial surface of aorta for four different experimental groups.
[0022] In the graphs, the results are expressed as mean ±S.E. The symbols used in FIGS. 1 to 5 have the following meanings.
[0023] *P<0.05, Comparison of values at different times with respect to time “0” in the respective group.
[0024] [0024] a P<0.05, Control vs other groups.
[0025] [0025] b P<0.05, Lignan complex vs 0.5% cholesterol or 0.5% cholesterol+lignan complex.
[0026] [0026] c P<0.5, 0.5% Cholesterol vs 0.5% cholesterol+lignan complex.
[0027] [0027] + P<0.05, Month 1 vs month 2 in the respective groups.
[0028] In FIGS. 6 and 7, the symbols have the following meanings:
[0029] *P<0.05, control Vs other groups; †P<0.05, lignan complex Vs 0.5% cholesterol or 0.5% cholesterol+lignan complex.
[0030] [0030] a P<0.05, 0.5% cholesterol Vs 0.5% cholesterol+lignan complex.
[0031] For FIG. 7, the significance symbols are as follows:
[0032] *P<0.05, control Vs other groups.
[0033] †P<0.05, 0.5% cholesterol Vs 0.5% cholesterol+lignan complex.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] The complex used according to this invention typically contains about 34 to 37% by weight of SDG, about 15 to 21% by weight cinnamic acid glucosides and about 9.6 to 11.0% by weight hydroxmethyl glutaric acid. The cinnamic acid glycosides include coumaric acid glucoside and ferulic acid glucoside. They are typically present in the complex in amounts of about 9.5 to 16.0% by weight coumaric acid glucoside and 4.5 to 5.0% ferulic acid glucoside.
[0035] The complex composition typically contains about 59 to 70% by weight of the above active ingredients. The balance comprises protein, ash and water of crystallization.
[0036] The invention is further illustrated by the following non-limiting examples.
EXAMPLE 1
[0037] Experimental Protocol
[0038] Experiments were conducted on New Zealand White rabbits. Rabbits were assigned to 4 groups as shown in Table 1. Those in Group I were fed rabbit laboratory chow diet. The other groups received lignan complex or cholesterol or cholesterol+lignan complex. The lignan complex was obtained from Agriculture and Agri-Food Canada and was extracted from flaxseed by the method described in Westcott et al., U.S. Pat. No. 6,264,853, incorporated herein by reference. The diet was especially prepared by Purina and did not contain any antioxidant. Lignan complex was given orally daily in the dose of 40 mg/kg body weight. The rabbits were cared for according to approved standards for laboratory animal care. The rabbits were on their respective diet treatment for 2 months.
[0039] Blood samples were collected (from ear marginal artery) for measurement of serum triglycerides (TG), total cholesterol (C), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), enzymes, albumin, creatinine, and malondialdehyde (MDA) before (0 time) and after 1 and 2 months on the respective experimental diets. The rabbits were anesthetized at the end of 2 months and aortas were removed for assessment of atherosclerotic plaques, and measurement of aortic tissue MDA and antioxidant reserve (Aortic-chemiluminescence). The measurement of lipids, atherosclerotic plaques, oxidative stress were done according to known methods. Serum enzymes, albumin and creatinine for assessment of liver and kidney function were measured by already established techniques. Assessment of hemopoietic system were made by established techniques available in the hospital.
[0040] SERUM LIPIDS. Changes in serum TG, C, LDL-C, and HDL-C in the 4 groups are shown in FIGS. 1 - 4 . Lignan complex did not affect serum TG, TC, LDL-C but increased HDL-C significantly in the groups on control diet. A 0.5% cholesterol diet increased serum TG, C, LDL-C and HDL-C. Lignan complex in 0.5% cholesterol-fed rabbit produced less increase in C and LDL-C, and greater increase in HDL-C as compared to only 0.5% cholesterol-fed rabbits. Serum TG levels were similar in Group III and IV.
[0041] These results indicate that the lignan complex lowers serum cholesterol (significantly) and LDL-C (not significant), and raises HDL-C (significantly) in hypercholesterolemic rabbit. Lignan complex also raises HDL-C in normocholesterolemic rabbits.
[0042] OXIDATIVE STRESS. Results for oxidative stress parameters (serum MDA, aortic tissue-MDA, aortic tissue antioxidant reserve) are shown in FIGS. 5 - 7 . Serum MDA levels remained unaltered in control and lignan complex groups. It increased in both 0.5% cholesterol and 0.5% cholesterol+lignan groups. However, the increase was less in groups with 0.5% cholesterol+lignan complex. Aortic MDA increased and lignan complex decreased in 0.5% cholesterol-fed rabbits. Aortic tissue chemiluminscence (Aortic-CL) is a measure of antioxidant reserve. An increase in Aortic-CL suggests a decrease in the antioxidant reserve and vice-versa. Aortic-CL decreased in cholesterol-fed group of rabbits. Lignan complex in cholesterol-fed rabbits tended to increase the aortic-CL compared to 0.5% cholesterol without lignan complex.
[0043] These results indicate that high cholesterol increases oxidative and the lignan complex reduces oxidative stress.
[0044] ATHEROSCLEROSIS. Representative photographs of endothelial surfaces of aortas from each group are depicted in FIG. 8, and the results are summarized in FIG. 9. In FIG. 8, Group I is Control, Group II is lignan complex, Group III is 0.5% cholesterol and Group IV is 0.5% cholesterol+lignan complex. In FIG. 9:
[0045] P<0.05, Group I or Group II vs Group III and Group IV.
[0046] †P<0.05, Group III vs Group IV.
[0047] Atherosclerotic plaques were absent in Group I and II. However, a significant area of aortic surface from Group III (50.84±6.23%) and Group IV (33.40±4.80%) was covered with atherosclerotic plaques.
[0048] This indicates that the lignan complex reduced the hypercholesterolemic atherosclerosis by 34.3%.
[0049] Hemopoietic System
[0050] Red Blood Cells (RBCs). The changes in various parameters related to RBC are shown in Tables 2-8. In general lignan complex in the control diet group (Group II) did not affect the RBC count, hemoglobin (Hb), hematocrit (Hct), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC) and red blood cell distribution width (RDW). Cholesterol diet (Group III) alone produced significant decreases in RBC, Hb, Hct and MCH; increases in RDW; and no change in MCV and MCHC. Lignan complex in 0.5% cholesterol-fed rabbits (Group IV) reduced RBC, Hb, and Hct; increased MCV, MCH and RDW. The values for RBC, Hb, Hct, MCV, MCH, MCHC and RDW in Group IV were not significantly different from those in Group III. This shows that, in general, the lignan complex has no adverse effects on the hemopoietic system.
[0051] White Blood Cells. The changes in the white blood cells (WBCs) and the differential counts granulocytes, lymphocytes, and monocytes are shown in Tables 9-12. Lignan complex in the control diet group (Group II) produced decreases in WBCs and monocytes, and no changes in granulocytes and lymphocytes. These changes in the various parameters in Group II were not significantly different from those in control group (Group I). These parameters of WBCs were unaffected in Group III and IV except in Group III where monocyte counts decreased.
[0052] These results indicate that lignan complex has no adverse effects on the WBCs, granulocytes, lymphocytes and monocyte counts.
[0053] PLATELET. The changes in platelet counts and mean platelet volume (MPV) of the four groups are summarized in Tables 13-14. Platelet counts slightly decreased in Group I but MPV remained unchanged. These parameters remained unaltered in Group II. Basically, all the parameters in all the groups remained unaltered. These results indicate that lignan complex has no adverse effects on platelet counts and mean platelet volume.
EXAMPLE 2
[0054] Studies were conducted to determine if the lignan complex given for 2 months produces adverse effects on liver and kidney function.
[0055] (a) Assessment of liver function was made by measuring serum enzymes [alkaline phosphatase (ALP), alanine amino-transferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyltransferase (GGT)] and serum albumin. These serum enzymes are elevated and serum albumin is decreased in liver disease. The results are summarized in Table 15-19. Serum levels of ALT, AST and GGT were similar in Groups I and II at month two of the protocol, however levels of serum ALP were lower in Group II compared to Group I. The changes in the serum levels of ALP, ALT and GGT remained unchanged as compared to “0” month in the Groups III and IV. However serum levels of AST increased to a similar extent in both groups III and IV. Serum albumin levels increased at month one as compared to “0” month in all the groups, however the increases at month two were not significantly different as compared to “0” month. The values of serum albumin at month two, although higher in Groups I and II as compared to Group III and IV, they were not significantly different from each other.
[0056] These results indicate that hypercholesterolemia has adverse effects on liver function and that the lignan complex does not have adverse effects on liver function.
[0057] (b) Assessment of kidney function was made by measuring serum enzymes (ALT and AST) and creatinine. ALT, AST and creatinine levels are elevated in dysfunctional kidney. The results are summarized in Tables 16, 17 and 20.
[0058] There were no significant differences in the values of serum ALT, AST and creatinine among the 4 groups.
[0059] These results indicate that the lignan complex or hypercholesterolemia did not have adverse effects on kidney function.
EXAMPLE 3
[0060] The lignan complex was also fed orally to normal rats for 2 months at a daily dosage of 40 mg/kg of body weight and the rats were studied to see if the complex had any affect on the liver and kidney function and hemopoietic cells. It was found that the lignan complex did not affect any of the above, indicating that it is not toxic to liver, kidney and blood cells.
TABLE 1 Experimental Diet Groups Group Diet/Treatment I (n = 10) Control (Rabbit chow diet) II (n = 6) Lignan complex control (Rabbit chow diet supplemented with lignan complex, 40 mg/kg body weight, orally, daily) III (n = 12) Cholesterol diet (0.5% cholesterol in rabbit chow diet) IV (= 16) Cholesterol diet + lignan complex (0.5% cholesterol diet supplemented with lignan complex, 40 mg/kg; body weight, orally, daily)
[0061] [0061] TABLE 2 Red Blood Cells (RBC) Counts (10 12 /L) in the Experimental Groups Time (months) Group 0 1 2 I. Control diet 5.08 ± 0.12 6.22 ± 0.18* 6.04 ± 0.16* II. Control diet + 5.76 ± 0.16 a 6.03 ± 0.13 5.90 ± 0.20 lignan complex III. 0.5% cholesterol 5.67 ± .07 a 5.61 ± 0.09 a,b 4.60 ± 0.11* ,†,a,b diet IV. 0.5% cholesterol 5.83 ± 0.09 a 5.43 ± 0.06* ,a,b 4.70 ± 0.14* ,†,a,b diet + lignan complex
[0062] [0062] TABLE 3 Hemoglobin Levels in the Blood (g/L) in the Experimental Groups Time (months) Group 0 1 2 I. Control diet 111.8 ± 1.6 133.8 ± 4.2* 128.9 ± 2.5* II. Control diet + 126.8 ± 2.2† 134.6 ± 2.4* 129.0 ± 3.1 lignan complex III. 0.5% cholesterol 125.1 ± 1.6† 122.8 ± 1.7 †,a 107.7 ± 2.2* ,†,a diet IV. 0.5% cholesterol 127.6 ± 1.6† 122.9 ± 1.8 †,a 110.0 ± 2.6* ,†,a diet + lignan complex
[0063] [0063] TABLE 4 Hematocrit (L/L) in the Experimental Groups Time (months) Group 0 1 2 I. Control diet 0.327 ± 0.385 ± 0.01* 0.376 ± 0.01* 0.00 II. Control diet + 0.357 ± 0.382 ± 0.01* 0.373 ± 0.01 lignan complex 0.00 a III. 0.5% cholesterol 0.364 ± 0.348 ± 0.01* ,a,b 0.300 ± 0.01* ,†,a,b diet 0.01 a IV. 0.5% cholesterol 0.372 ± 0.347 ± 0.01* ,a,b 0.310 ± 0.01* ,†,a,b diet + lignan 0.00 a complex
[0064] [0064] TABLE 5 Mean corpuscular volume (fL) in the Experimental Groups Time (months) Group 0 1 2 I. Control diet 64.4 ± 0.9 61.8 ± 0.9 62.3 ± 0.9 II. Control diet + 62.4 ± 1.1 63.4 ± 1.0 63.3 ± 0.8 lignan complex III. 0.5% cholesterol 64.2 ± 0.4 62.2 ± 0.4* 65.3 ± 0.5 †,a diet IV. 0.5% cholesterol 63.8 ± 0.6 64.0 ± 0.6 c 66.1 ± 0.6* ,†,a,b diet + lignan complex
[0065] [0065] TABLE 6 Mean Corpuscular Hemoglobin (pg) in the Experimental Groups Time (months) Group 0 1 2 I. Control diet 22.0 ± 0.34 21.5 ± 0.26 21.4 ± 0.32 II. Control diet + 22.1 ± 0.38 22.4 ± 0.33 21.9 ± 0.34 lignan complex III. 0.5% cholesterol 22.1 ± 0.15 22.0 ± 0.24 23.4 ± 0.20* ,†,a,b diet IV. 0.5% cholesterol 21.9 ± 0.26 22.7 ± 0.19* ,a,c 23.4 ± 0.23* ,†,a,b diet + lignan complex
[0066] [0066] TABLE 7 Mean Corpuscular Hemoglobin Concentration (g/L) in the Experimental Groups Time (months) Group 0 1 2 I. Control diet 341.8 ± 3.8 347.6 ± 1.8 343.3 ± 1.5 II. Control diet + 354.2 ± 1.7 352.5 ± 1.7 346.2 ± 2.4* lignan complex III. 0.5% cholesterol 343.5 ± 1.5 351.7 ± 2.5 357.7 ± 1.9 diet IV. 0.5% cholesterol 342.9 ± 2 354.6 ± 3.0 354.9 ± 1.7 diet + lignan complex
[0067] [0067] TABLE 8 Red Blood Cell Distribution Width (RDW) as % in the Experimental Groups Time (months) Group 0 1 2 I. Control diet 11.68 ± 0.22 12.44 ± 0.37 12.84 ± 0.35 II. Control diet + 13.52 ± 0.28 a 13.1 ± 0.33 12.95 ± 0.32 lignan complex III. 0.5% cholesterol 11.56 ± 0.20 b 12.3 ± 0.14* ,b 13.42 ± 0.3* ,† diet IV. 0.5% cholesterol 12.2 ± 0.27 b 13.1 ± 0.29* ,c 13.17 ± 0.21* diet + lignan complex
[0068] [0068] TABLE 9 White Blood Cell Counts (10 9 /L) in the Experimental Groups Time (months) Group 0 1 2 I. Control diet 4.96 ± 0.62 5.34 ± 0.77 5.3 ± 0.38 II. Control diet + 7.7 ± 0.7 a 7.33 ± 0.25 a 4.85 ± 0.78* ,† lignan complex III. 0.5% cholesterol 6.34 ± 0.33 8.5 ± 0.48* ,a 6.88 ± 0.73 diet IV. 0.5% cholesterol 6.05 ± 0.28 b 9.14 ± 0.44* ,a,b 6.59 ± 0.93 † diet + lignan complex
[0069] [0069] TABLE 10 Granulocytes Content of Blood (10 9 /L) in the Experimental Groups Time (months) Group 0 1 2 I. Control diet 0.96 ± 0.12 0.64 ± 0.08 1.02 ± 0.15 II. Control diet + 1.14 ± 0.18 1.21 ± 0.08 a 0.65 ± 0.09 † lignan complex III. 0.5% cholesterol 1.10 ± 0.08 1.75 ± 0.27* ,a 1.36 ± 0.23 diet IV. 0.5% cholesterol 0.87 ± 0.078 1.21 ± 0.20 1.84 ± 0.38* diet + lignan complex
[0070] [0070] TABLE 11 Lymphocyte Counts in Blood (10 9 /L) in the Experimental Groups Time (months) Group 0 1 2 I. Control diet 3.42 ± 0.44 4.22 ± 0.69 4.0 ± 0.29 II. Control diet + 5.27 ± 0.33 a 5.53 ± 0.27 a 3.87 ± 0.65 † lignan complex III. 0.5% cholesterol 4.19 ± 0.19 b 6.41 ± 0.51* 4.74 ± 0.46 † diet IV. 0.5% cholesterol 4.65 ± 0.27 a 5.02 ± 0.74 5.09 ± 0.56 diet + lignan complex
[0071] [0071] TABLE 12 Monocyte Counts in the Blood (10 9 /L) in the Experimental Groups Time (months) Group 0 1 2 I. Control diet 0.56 ± 0.07 0.46 ± 0.05 0.28 ± 0.07* II. Control diet + 0.62 ± 0.07 0.58 ± 0.047 0.33 ± 0.08* ,† lignan complex III. 0.5% cholesterol 0.75 ± 0.07 0.75 ± 0.08 a 0.37 ± 0.05* ,† diet IV. 0.5% cholesterol 0.45 ± 0.05 c 0.56 ± 0.09 0.45 ± 0.02 a diet + lignan complex
[0072] [0072] TABLE 13 Platelet Counts in the Blood (10 9 /L) in the Blood of Various Experimental Groups Time (months) Group 0 1 2 I. Control diet 393 ± 46 324 ± 52 286 ± 25* II. Control diet + 329 ± 20 280 ± 8* 267 ± 23 lignan complex III. 0.5% cholesterol 422 ± 24 b 341 ± 26* 401 ± 31 a,b diet IV. 0.5% cholesterol 403 ± 20 b 309 ± 23* 364 ± 37 diet + lignan complex
[0073] [0073] TABLE 14 Mean Platelet Volume in Fentoliter (fl) for Various Experimental Groups Time (months) Group 0 1 2 I. Control diet 5.38 ± 0.27 5.64 ± 0.21 5.69 ± 0.21 II. Control diet + 6.03 ± 0.16 5.81 ± 0.11 5.75 ± 0.11 lignan complex III. 0.5% cholesterol 5.37 ± 0.07 a 5.27 ± 0.09 a 5.96 ± 0.11* ,† diet IV. 0.5% cholesterol 5.51 ± 0.7 a 5.47 ± 0.07 a 5.85 ± 0.11* ,† diet + lignan complex
[0074] [0074] TABLE 15 Serum Alkaline Phosphatase (ALP) Levels (U/L) in the Experimental Groups Time (months) Group 0 1 2 I. Control diet 121.3 ± 20.2 152.6 ± 10.9 118.1 ± 7.7 † II. Control diet + 71.0 ± 9.65 a lignan complex III. 0.5% cholesterol 169.1 ± 16.6 191.5 ± 15.6 160.3 ± 11.6 a,b diet IV. 0.5% cholesterol 142.7 ± 1.4 181.2 ± 7.9* 132.7 ± 19.5 diet + lignan complex
[0075] [0075] TABLE 16 Serum Alanine Aminotransferase (ALT) Levels (U/L) in the Experimental Groups Time (months) Group 0 1 2 I. Control diet 27.25 ± 3.6 44.2 ± 5.85 41.2 ± 3.5* II. Control diet + Not Not 47.33 ± 9.2 lignan complex measured measured III. 0.5% cholesterol 41.22 ± 3.1 a 59.3 ± 11.2 69.08 ± 13.3 diet IV. 0.5% cholesterol 41.6 ± 2.6 a 45.4 ± 9.4 39.1 ± 5.6 diet + lignan complex
[0076] [0076] TABLE 17 Serum Aspartate Aminotransferase (AST) Levels (U/L) in the Experimental Groups Time (months) Group 0 1 2 I. Control diet 25.0 ± 5.1 25.4 ± 0.5 41.1 ± 3.6* ,† II. Control diet + Not Not 34.7 ± 4.4 lignan complex measured measured III. 0.5% cholesterol 35.0 ± 3.3 44.1 ± 6.5 53.1 ± 2.4* ,a diet IV. 0.5% cholesterol 28.8 ± 4.4 29.6 ± 2.4 49.4 ± 4.5* ,† diet + lignan complex
[0077] [0077] TABLE 18 Serum Levels (U/L) of Gamma-glutamyltransferase (GGT) in the Experimental Groups Time (months) Group 0 1 2 I. Control diet 9.0 ± 0.8 8.8 ± 1.0 8.0 ± 1.9 II. Control diet + Not Not 8.0 ± 1.3 lignan complex measured measured III. 0.5% cholesterol 9.6 ± 0.4 8.6 ± 0.8 6.4 ± 1.7 diet IV. 0.5% cholesterol 9.0 ± 1.1 6.5 ± 0.6 6.4 ± 1.2 diet + lignan complex
[0078] [0078] TABLE 19 Serum Albumin Levels (gm/L) in the Experimental Groups Time (months) Group 0 1 2 I. Control diet 15.8 ± 0.2 17.8 ± 0.37* 30.3 ± 5.2 II. Control diet + 35.50 ± 4.52 lignan complex III. 0.5% cholesterol 16.9 ± 0.31 18.3 ± 0.42* 20.41 ± 2.58 diet IV. 0.5% cholesterol 17.2 ± 0.2 19.0 ± 0.54* 26.77 ± 4.1 diet + lignan complex
[0079] [0079] TABLE 20 Serum Creatinine Levels (μmoles/L) in the Experimental Groups Time (months) Group 0 1 2 I. Control diet 48.4 ± 2.46 78.8 ± 2.35* 103.3 ± 5.4* ,† II. Control diet + Not Not 104.25 ± 6.2* lignan complex measured measured III. 0.5% cholesterol 62.12 ± 1.68 a 80.7 ± 3.9* 106.4 ± 4.6* ,† diet IV. 0.5% cholesterol 60.0 ± 6.0 73.2 ± 3.7 97.56 ± 5.33* ,† diet + lignan complex
[0080] Since lignan complex lowers serum cholesterol, elevates serum HDL-C and reduces hypercholesterolemic atherosclerosis it will be of use in the prevention and treatment of the following diseases:
[0081] i) Hypercholesterolemic atherosclerosis.
[0082] ii) Coronary artery disease (heart attack).
[0083] iii) Stroke.
[0084] iv) Restenosis following percutaneous transluminal coronary angioplasty.
[0085] v) Restenosis after stent implant.
[0086] vi) Stroke, heart attack, renal failure and retinopathy in diabetes mellitus.
[0087] vii) Hypercholesterolemia.
[0088] viii) Peripheral vascular diseases, such as intermittent clandication.
[0089] The use of lignan complex derived from flaxseed according to this invention has the following advantages:
[0090] i) Lignan complex contains materials that have antioxidant and anti-PAF activity and hence is an anti-inflammatory agent.
[0091] ii) It lowers serum cholesterol, raises HDL-C and reduces hypercholesterolemic atherosclerosis.
[0092] iii) This compound is a natural food product and has no toxicity on hemopoietic system, liver and kidney, and it is a safe drug.
[0093] iv) It is inexpensive and safe as compared to other drugs used for lowering lipids and reducing atherosclerosis.
[0094] v) This compound is cheaper than SDG because processing of SDG is expensive as compared to lignan complex.
[0095] vi) The dose of lignan complex is very small as compared to flaxseed. | A method is described for treating hypercholesterolemic atherosclerosis or for reducing total cholesterol while raising high-density lipoportoein cholesterol. It involves administering to a patient a substantially pure complex derived from flaxseed and containing secoisolariciresinol diglucoside (SDG), cinnamic acid glucosides and hydroxymethyl glutaric acid. | 0 |
SEQUENCE LISTING
An attached Sequence Listing (i. Name: SEQ_LISTING, ii. Date of Creation: Nov. 18, 2015, and iii. Size: 1 KB) is submitted herewith.
FIELD OF THE INVENTION
The invention concerns the use of the PAT nonapeptide for the manufacturing of a drug in the treatment or the prevention of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease or amyotrophic lateral sclerosis.
BACKGROUND OF THE INVENTION
The neurodegenerative diseases affect progressively the brain function and more generally the nervous system. The process involved consists generally in a deterioration of the functioning of the nervous cells, in particular the neurons, leading to the cellular death. The consequence for the patient is a progressive alteration, usually irreversible, of the nervous functions which can induce his death. The clinical outcome can be either some damages of the psychic function, leading to dementia such as in Alzheimer's or Pick's disease, or motor abnormalities such as in amyotrophic lateral sclerosis or Parkinson's disease, or the combination of both such in Huntington's chorea disease or Creutzfeldt-Jacob's disease.
Alzheimer's disease (AD) is the most known and spread of the neurodegenerative diseases. It is characterized by memory loss and sometimes by disorders of reasoning, organization, language and perception. It is widely admitted that the AD symptoms arise from an increase of the production or accumulation of a specific protein (β-amyloid) in the brain, which leads to the death of nervous cell. Increasing age is the greatest know risk factor for AD. Approximately 30 millions of people in the world are affected by AD. Population ageing suggests that the economic burden caused by AD disease will become increasingly important.
Parkinson's disease (PD) is the second most common neurodegenerative disorder in the United States and approximately 1-2% of worldwide population older than 65 years suffers from this progressive disease (Dorsey E R. et al. Neurology 2007; 68: 384). The predominant motor symptoms of PD including slow movement, resting tremor, rigidity and gait disturbance are caused by the loss of dopaminergic neurons in the substantia nigra. Although the etiology of PD remains so far unknown, both genetic and environmental factors appear to play a role (Paisan-Ruiz C. et al. Neuron. 2004; 44: 595 and Vila M. and Przedborski S. Nat. Med. 2004; Suppl 10: S58).
Huntington's disease (HD) is an autosomal dominant inherited and progressive neurodegenerative disease that affects approx. 30,000 individuals in the US (about 200,000 individuals are at risk) (Harper P S. Hum. Genet. 1992; 89: 365). HD is clinically characterized by abnormal involuntary movements, behavioral disturbance, cognitive dysfunction and psychiatric disease. Massive loss of GABAergic medium spiny neurons (MSNs) of the striatum occurs in the HD brain together with enlargement of the ventricles and a corresponding shrinkage of the overlying cortex. MSNs of the striatum project into various regions of the CNS and are the key drivers of the progression of degenerative process that involves the remainder of the basal ganglia and subsequent dissemination including cortex and substantia nigra (Andric J. et al. Neurosci. Lett. 2007; 416: 272 and Frank S et al. Neurology. 2004; 62: A204). Dopamine, glutamate and γ-aminobutiric acid (GABA) are thought to be the most affected neurotransmitters in HD (Gunawardena S. et al. Arch. Neurol. 2005; 62: 46).
Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disorder characterized by selective motor neuron death. Both upper motor neurons in the motor neuron cortex and lower motor neurons in the brainstem and in the ventral horn of the spinal cord are affected. Patients develop a progressive muscle phenotype characterized by spasticity, hyperreflexia, fasciculations, muscle atrophy and paralysis. ALS is usually lethal within 3 to 5 years after diagnosis, only 5-10% of patients survive beyond 10 years. There are approximately 140,000 new cases diagnosed worldwide each year. In most cases (90%) there is no family history of ALS. However a clear family history is present in 10% of patients who then suffer from familial ALS. Although the familial ALS is in almost all cases inherited in an autosomal dominant way, autosomal recessive and X-linked forms exist. Mutations in more than 10 different genes are known to cause familial ALS. Many mechanisms have been suggested to play a role in the pathogenesis and disease progression. These include amongst others neuronal excitotoxicity, mitochondrial dysfunction, deregulated autophagy, axonal transport dysfunction and refraction (Cudkowicz M E Ann. Neurol. 1997 41, 210-221).
Albeit, there is currently no treatment leading to the AD recovery, there are 2 types of drugs which can decrease its symptoms and slow down its evolution. EP236684A, DE 3805744A and EP296560A disclose drugs based on acetylcholinesterase inhibitors: galantamine, rivastigmine and donepezil respectively. EP392059A discloses a drug containing memantine which is a NMDA receptor antagonist. All these drugs have received a marketing authorization to treat AD. However, the treatment only affects the symptoms. Several studies have shown that these drugs slow down only in a modest way the progression of cognitive symptoms as well as erratic behaviors in some patients. Moreover, half of the patients who received these drugs do not respond to these treatments. Finally, these drugs induce several undesirable effects such as nausea, diarrhea, hepatic disorders etc. . . . . Thus, there is an urgent need for drugs with a new mechanism of action different from the aforementioned drugs. Several projects are being explored currently. Few examples are mentioned hereafter.
The secretase inhibitors block the transformation process of the β-amyloid protein precursor (known as “APP”) into the β-amyloid protein and thus permit to slow down its dangerous accumulation in the brain. Among these inhibitors is the tramiprosate (ALZHEMED®) which was tested in a phase II clinical study (Aisen P S et al. Neurology 2006; 28: 1757). Another inhibitor, the scillo-cyclohexanehexol, was tested in animals successfully (MacLarin J A et al. Nat. Med. 2006; 12: 801). These molecules interact with β-amyloid proteins during their formation and prevent them from agglomerating and from forming small aggregates, which destroy nervous cells by settling as solid plaques. However, they already cause important damage during their formation.
Other treatments such as ubiquitin (compound naturally produced in the brain) induce the disappearance of β-amyloid protein before its reaches high accumulation in the brain (Taddei N. et al. Neurosci. Lett. 1993; 151: 158). However, the ubiquitin rates remain insufficient in patients which suffer from Alzheimer's disease.
Another interesting method is the immunological approach. WO 94/06476A discloses a new type of drug which has a target different from the molecules cited previously: Etanercept (ENBREL®), which is a fusion protein directed against the TNF-α pro-inflammatory cytokine A recent pilot study was carried out over a 6 months period and showed encouraging results in term of cognitive improvement (Tobinick E. CNS Drugs 2009; 23: 713). In addition to the fact that the project is at a preliminary phase at the clinical level, the administration of the product ENBREL® was carried out by perispinal route in order to circumvent the problem linked to its incapacity to pass across the blood-brain barrier (BBB) (Griffin S. Newspaper of Neuroinflammation; 2008; 5: 3). However, this route of administration is burdensome and painful for the patient and requires a certain number of precautions: it must be carried out in hospitals. The presence of the blood-brain barrier (BBB) restricts strongly the passage of molecules such as ENBREL® from the plasma into the cerebral extracellular medium: very few drugs designed in laboratories, cross this barrier to treat brain diseases.
Limited therapeutic options are available to PD, HD and ALS patients as only symptomatic treatments have received marketing authorizations so far. The major challenge for clinical development of new drug entities in neurodegenerative disorders lies in the difficulty to identify and hit disease-relevant targets that will beneficially interfere with complex physiopathological mechanisms. Moreover such therapeutic agent must cross the BBB and reach diseased regions of the central nervous system. U.S. Pat. Nos. 4,900,755 and 6,238,699 disclose an oral formulation for the controlled release of the combination of levodopa/carbidopa (SINEMET®). This treatment compensates for the loss of dopaminergic neurons that occurs in PD brains. Carbidopa, a decarboxylase inhibitor, prevents peripheral metabolism of levodopa, the precursor of dopamine, outside of the brain. In the brain levodopa is broken down into dopamine which increases dopamine concentration in the striatum. Levodopa, dopamine precursor is used because the natural neurotransmitter does not cross the BBB. Tetrabenazine (XENAZINE®) is an oral dopamine-depleting agent that treats chorea associated with HD. Dopamine is required for fine motor movement, so the inhibition of its transmission is efficacious for hyperkinetic movement. Tetrabenazine is a reversible human vesicular monoamine transporter type 2 inhibitor. It acts within the basal ganglia and promotes depletion of monoamine neurotransmitters serotonin, norepinephrine, and dopamine from stores. It also decreases uptake into synaptic vesicles (Guay D. Am. J. Geriatr. Pharmacother. 2010; 8: 331). Finally, riluzole (RILUTEK®) is the only approved treatment for ALS which increases lifespan by only 2-3 months after 1.5 years of treatment, and is effective at delaying the use of assisted mechanical ventilation in bulbar patients (Miller R G et al. Neurology 2009; 73: 1218 and Bellingham M C. CNS Neurosci. Ther. 2011; 17: 4). Pharmacological properties of riluzole include an inhibitory effect on glutamate release mediated by inactivation of voltage-dependent sodium channels and by its ability to interfere with intracellular events that follow transmitter binding at excitatory amino acid receptors. Although these drugs reduce cognitive or motor symptoms and improve quality of life, they fail to modify or halt disease progression. Their long-term use is associated with side-effects that often require treatment arrest.
Therefore, there is a need for drugs which should at the one hand be sufficiently effective to treat AD, PD, HD or ALS and on the other hand cross the BBB. The Applicant objective is to develop a drug capable to treat of Alzheimer's disease and other neurodegenerative disorders without presenting the disadvantages of the existing treatments. The Applicant has found, in a fortuitous way, due to the work already carried out with this molecule, that a peptide analog of thymulin hormone has an interesting potential in the prevention and the treatment of AD, PD, HD and ALS.
We know since the late 1950's the central role played by the thymus in the differentiation of T-cells, responsible in particular of transplant rejection and implicated in the immune defense against the viruses and some bacteria. The hormone secreted by the thymus was then identified as a peptide of 9 amino-acids: the thymulin (Pleau J M et al. Immunol. Lett, 1979; 1:179; Amor et al, Annals Rheum. Dis. 1987; 46: 549). The thymulin effects on the immune system were shown to be zinc-dependent. Indeed, zinc confers to the thymulin a tetrahedral conformation which corresponds to the active form of the molecule. In the absence of zinc, thymulin is no longer active on the immune system. Work was undertaken specifically on a nonapeptide called “PAT” having the sequence of amino-acids Glu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asp (EAKSQGGSD). The application WO 03/030927A reports that several derivatives of thymulin, such as the PAT nonapeptide presents analgesic and anti-inflammatory properties, and can treat in pain including neurogenic pain. More recently, the application WO 2009/150310A describes specifically the use of the PAT nonapeptide in the treatment of autoimmune diseases such as rheumatoid arthritis, and intestinal bowel diseases (IBD) such as Crohn's disease and hemorrhagic rectocolitis.
SUMMARY OF THE INVENTION
The present invention refers to the use of the PAT nonapeptide corresponding to the formula (I):
EAKSQGGSD
or one of its pharmaceutically acceptable salts in the preparation of a drug in the treatment and the prevention of neurodegenerative diseases, in particular Alzheimer's disease Parkinson's disease, Huntington's disease and amyotrophic lateral sclerosis.
The PAT peptide is administered to the human or the animal at a dose ranging between 0.1 and 50 mg; and preferably between 1 and 10 mg. By “pharmaceutically acceptable salt”, one understands as example and in a nonrestrictive way acetate, sulfate or hydrochlorate. The invention also relates to the use of a compound of formula (I) in which one or more amino-acids are in the D configuration.
The pharmaceutical composition of the invention can be administered by parenteral, topical, oral, perlingual, rectal or intraocular route. The preferred administration route is the parenteral route, and in particular the cutaneous (s.c.), intranasal, intra-peritoneal (i.p.) or intravenous (i.v.) routes. It can also be considered a topical route, in particular transderrmal, such as for example, as a patch, pomade or gel.
During an experiment carried out for the invention, it was shown that the PAT nonapeptide displays a biological activity when it is administered by intracerebroventricular (i.c.v.) route—which bypasses the BBB, and also by parenteral route (intra-peritoneal). This latter mode of administration highlights the fact that the product crosses the BBB and reaches the brain. To cross the BBB, persons skilled in the art know that the molecular and physicochemical properties of the molecule must fulfill the 5 criteria described by Lipinski et al. (1997). Adv Drug Del Rev 23: 3-25 (amongst them a low molecular weight, its hydrophobicity, its charge etc. . . . ). Yet, we were surprised to notice that the PAT peptide, which does not fulfill all these criteria, crosses the BBB.
The formulations to be administered by parenteral route contain a solvent allowing the solubilization of a peptide such as the PAT peptide; this solvent can be selected among the water for injection or physiological saline solution, optionally with preservative agents (such as cresol, phenol, benzyl alcohol or methylparaben) and/or buffer agents, and/or isotonic adjuvants and/or surfactants well-known by persons skilled in the art.
One of the preferred administrations is the subcutaneous (s.c.) route. The injectable form by subcutaneous route according to the invention contains the PAT peptide dissolved in an appropriate solvent, with if necessary other excipients such as those cited previously. One of the injectable subcutaneous forms according to the invention contains a polymer which allows a slow diffusion of the PAT peptide during the time course (period up to 30-40 days). In order to achieve that, PAT peptide is dissolved in an appropriate solvent such as a physiological saline solution, and mix with appropriate polymers such as the polyethylene glycols, polyvinyl pyrrolidones and polyacrylamides.
BRIEF DESCRIPTION OF THE DRAWINGS
Other advantages and characteristics of the invention will become clear upon reading the following examples. Reference is made to the appendix drawings in which:
FIG. 1 shows the results obtained from Y-maze test in mice having received by (i.c.v.) intracerebroventricular route either the ScAβ (“scrambled”) peptide or the Aβ 25-35 peptide, and also by intra-cerebroventricular (i.c.v.) route an inert (V) vehicle or the PAT peptide. The evaluated parameter is the spontaneous alternation expressed as a percentage;
FIGS. 2A and 2B show the results obtained from passive avoidance test; the treated groups are identical to those of FIG. 1 ; in FIG. 2A is measured the latency time (in seconds) to enter into the dark compartment; and in FIG. 2B is measured the latency time to escape (in seconds);
FIG. 3 shows the results obtained from Y-maze test under the same conditions as for FIG. 1 , except that the PAT peptide and the inert (V) vehicle are injected by intra-peritoneal (i.p.) route;
FIGS. 4A and 4B show the results obtained from passive avoidance test carried out such as for FIG. 2 except that the PAT peptide and the inert (V) vehicle are injected by intra-peritoneal (i.p.) route; in FIG. 4A is measured the latency time (in seconds) to enter into the dark compartment; and in FIG. 4B is measured the latency time to escape (in seconds).
FIGS. 5A and 5B show the results obtained from in vitro tests performed with rat primary dopaminergic neurons; in FIG. 5A is depicted the quantitative representation of the protective effect of PAT on the survival of TH-positive dopaminergic neurons exposed to 6-hydroxydopamine (6-OHDA) injury and pre-treated with vehicle (V), survival promoting brain derived neurotrophic factor (BDNF) or increasing concentrations of PAT (0.1 to 1000 nM). The evaluated parameter is the survival of TH-positive dopaminergic neurons (% of control condition, Ctrl). FIG. 5B show examples of microscopic aspect of neurons in control culture conditions (control), injured by 6-OHDA or pretreated with 10 nM PAT before 6-OHDA application are given.
FIGS. 6A and 6B show the results obtained from in vitro tests performed with rat primary GABAergic medium spiny neurons; in FIG. 6A is depicted the quantitative representation of the protective effect of PAT on the survival of GAD67-positive GABAergic neurons exposed to glutamate injury and pre-treated with vehicle (V), survival promoting brain derived neurotrophic factor (BDNF) or increasing concentrations of PAT (0.1 to 1000 nM). The evaluated parameter is the survival of GAD67-positive GABAergic neurons (% of control condition, Ctrl). FIG. 6B shows examples of microscopic aspect of medium spiny neurons in control culture conditions (control), injured by glutamate or pretreated with 10 nM PAT before glutamate application are given.
DETAILED DESCRIPTION OF THE INVENTION
In FIGS. 1 to 4B , one-way ANOVA followed by Dunnett's post hoc test was applied to the results: (*) means that the results are significant with a probability of <0.0001; (**) with a p<0.01 vs. ScAβ+V treatment group; (#) with a p<0.05 vs. (Aβ25-35+V) treatment group and (##) with a p<0.01 vs. (Aβ25-35+V) treatment group. In FIGS. 5A-5B and 6A-6B , statistical significance was determined by applying one-way ANOVA followed by Dunnett's test to the results: (*) means that the results were significant with a probability of <0.005 vs. 6-OHDA or glutamate condition respectively.
Example 1
Alzheimer's Model in Mice—Spontaneous Alternation Test
Experimental Protocol
The Swiss OF-1 (Depré, St Doulchard, France) mice were 7-9 weeks old from and weigh 32±2 g. They were dispatched into several groups and placed in plastic cages. They had free access to food and water, except during the behavioral experiments, and were maintained in an environment controlled (23±1° C., 40-60% of moisture) with light/darkness cycles of 12 hrs (light on at 8:00 am). The experiments were carried out between 9:00 am and 5:00 pm, in a room of experimentation. The mice were acclimated during 30 minutes before the beginning of the experiment. All the protocols followed the directives of the European Union dating of Nov. 24, 1986.
Treatment
The PAT peptide (5 μg) synthesized by Polypeptide (Denmark) was solubilized in distilled water and was administered by intra-peritoneal (i.p.) route in a volume of 100 μl (by 20 g of body weight) or by intra-cerebroventricular (i.c.v.) route at the same time as the amyloid peptide. The β [25-35] amyloid peptide called Aβ 25-35 and the Aβ25-35 “scrambled” peptide—called Sc.Aβ—were purchased from Genepep (France). They were resuspended in sterile distilled water at a concentration of 3 mg/ml and were preserved at 20° C. until their use. Before being injected, the peptides were subjected to an aggregation at 37° C. during 4 days. They are administered by i.c.v route in a final volume of 3 μl per mouse. The animals were tested at Day 7 after the injection.
In a first set of experiments, the mice received intracerebral (i.c.v.) administration of either water, or PAT nonapeptide (5 μg) at the same time than the ScAβ peptide or the Aβ 25-35 peptide (9 nmol). After a 7-days period, their performance in the spontaneous alternation test was evaluated. The numbers of animals per group were respectively 10 and 11. In a 2 nd set of experiments, the same test was performed, except that the PAT peptide was administered by intra-peritoneal (i.p.) route.
Test Course—Measured Parameters
We placed each mouse, which was not familiar with the device, at an end of a Y-maze (3 arms of 50 cm length and separated from 60°) and we let it move freely during 8 minutes. The number of entries in each arm, including the possible returns in the same arm, was counted visually. An entry was counted when the forelegs of the animal came at least 2 cm in the arm. An alternation was counted when an entry was made in all the 3 arms during successive tests. The number of total possible alternations was then the total number of entries minus 2 and the percentage of alternations was calculated as: (counted alternations/total of possible alternations)×100. The animals making less than 8 entries in 8 minutes were discarded from the experimental groups. No animal was excluded in this study. The compounds were administered 30 minutes before the session.
Results
The results are shown in FIG. 1 and FIG. 3 for the i.c.v. and i.p. administration routes, respectively.
As expected, when the Aβ 25-35 peptide was administered, the symptoms of Alzheimer's disease were induced. Administration of the control ScAβ peptide had no effect.
As expected, we observed that in FIG. 1 (i.c.v. route) when the ScAβ peptide was administered to the mice (which do not show any symptom of Alzheimer's disease) the co-administration of the PAT peptide had no effect. In contrast, co-administration of PAT peptide with the Aβ 25-35 peptide (thus the mice reproduce memory symptoms) exerted a significant neuroprotective effect on learning deficits induced by the Aβ 25-35 peptide.
In FIG. 3 (i.p. route), we also noticed a neuroprotective effect of the PAT peptide and this effect was very significant for the dose of PAT peptide between 1 and 3 mg/kg of body weight.
Example 2
Alzheimer's Model in Mice—Passive Avoidance Test
Experimental Protocol:
The information relative to the mice, the peptides, their administration and the treatment groups are similar to those of Example 1.
Test Course. Tested Parameters
The compounds were administered 30 minutes before the test. This test allowed the evaluation of the long term non-spatial memory. The device in the test consisted of an enlightened compartment having white PVC walls (with width/length/height dimensions of 15-20-15 cm respectively); an obscure compartment having black PVC walls (with same dimensions) and a grid on the ground. A trap door separated the 2 compartments. A lamp of 60 W was positioned 40 cm above and lightens the white compartment during the experiment. On the grid, random electric shocks of 0.3 mA were delivered to the mice legs during 3 seconds from a random power generator (Lafayette Instruments, USA).
The 1 st phase of the experiment called “training” was carried out first. The trap door was closed at the beginning of the exercise. Each mouse was placed in the white compartment. The trap door was lifted after 5 seconds. When the mouse entered into the dark compartment and touched the grid with all its legs, the trap door was closed and the random electric shock was delivered on the legs during 3 seconds. The latency time before the entry into the dark compartment and the number of counts were recorded. The number of counts did not differ between the groups, indicating that the sensitivity to the electric shock was not affected by the type of administration route i.e. here i.c.v. or i.p. (not shown results). The animals for which the latency time was out the range of 3-30 seconds were discarded from the experiment. The attrition rates accounted for less than 2% of the animals and were independent of the treatment.
The 2 nd phase of the experiment called “retention” was carried out 24 h after the 1 st phase (“training”). Each mouse was placed again in the white compartment. The trap door was raised after 5 seconds. The latency time of entry into the dark compartment was recorded during a 300 seconds period. The number of entries and the time of escape (time spent going back into the white compartment) were measured during a 300 seconds period.
Results
The results are presented in FIGS. 2 ( 2 A and 2 B) for the administration by i.c.v. route; and in FIGS. 4 ( 4 A and 4 B) for the administration by i.p. route.
The FIG. 2 —administration by i.c.v. route—shows clearly that the injection of the PAT peptide (5 μg) by i.c.v. route in mice having received the Aβ 25-35 peptide (the latter reproducing training deficits) improved the 2 criteria tested when they were compared to mice having received water distilled (V) only. Thus, by using this animal model of Alzheimer's disease, it was demonstrated that the PAT peptide presented at a significant neuroprotective effect.
Again, in FIG. 4 —administration by i.p. route—a neuroprotective effect of PAT peptide was observed. As in the spontaneous alternation test, the neuroprotective effect of the PAT was observable for a dose higher than 0.3 mg/kg of body weight.
Thus, the use of the 2 animal models of Alzheimer's disease shows that the PAT peptide is an interesting and promising candidate to treat and prevent cerebral lesions related to the training deficit.
Example 3
Cellular Model of Parkinson's Disease—Survival of Rat Primary Dopaminergic Neurons after 6-Hydroxydopamine Injury
6-hydroxydopamine (6-OHDA) is a selective catecholaminergic neurotoxin that is not only used as a pharmacological agent able to trigger PD-like stigmata (Sauer H. and Oertel W H Neuroscience 1994; 59: 401 and Cass W A et al. Brain Res. 2002; 938: 29) but also likely corresponds to a natural dopaminergic catabolite that accumulates in PD-affected brains and that appears to strongly contribute to this pathology (Jellinger K. et al. J. Neural. Transm. 1995; 46: 297). For this reason, 6-OHDA-induced dopaminergic neurotoxicity in mice is widely used as a model for PD research. Because 6-OHDA also induces neurodegeneration of dopaminergic neurons in vitro, it provides a useful model of PD. In this in vitro test mesencephalic dopaminergic neurons are exposed to 6-OHDA injury. Neuroprotective effect of a test compound is evaluated by pre-incubating the mesencephalic neurons for 1 h before the 6-OHDA application. After 24 h of intoxication, viable dopaminergic neurons are visualized and quantified by staining with a monoclonal Anti-Tyrosine Hydroxylase (TH) antibody. Tyrosine Hydroxylase is the first and rate-limiting enzyme involved in the biosynthesis of catecholamines like dopamine and norepinephrin from Tyrosine and has a key role in the physiology of adrenergic neurons. Tyrosine hydroxylase is commonly used as a marker for dopaminergic neurons, which is particularly relevant for research in Parkinson's disease. Brain derived neurotrophic factor (BDNF) is used as a positive control that has been shown to reduce the 6-OHDA-induced neurodegeneration in vitro (Riveles K et al. Neurotoxicology 2008; 29: 421).
Experimental Protocol
Rat dopaminergic neurons were cultured as described by Schinelli et al. J. Neurochem. 1988; 50: 1900 and Visanji N P et al. FASEB J. 2008; 22: 2488. Briefly, the midbrains obtained from 15-day old rat embryos (Janvier, France) were dissected under a microscope. The embryonic midbrains were removed and placed in ice-cold medium of Leibovitz (L15) containing 2% of Penicillin-Streptomycin (PS) and 1% of bovine serum albumin (BSA). The ventral portion of the mesencephalic flexure, a region of the developing brain rich in dopaminergic neurons, was used for the cell preparations.
The midbrains were dissociated by trypsinisation for 20 min at 37° C. (Trypsin EDTA 1X). The reaction was stopped by the addition of Dulbecco's modified Eagle's medium (DMEM) containing DNAase I grade II (0.1 mg/ml) and 10% of fetal calf serum (FCS). Cells were mechanically dissociated by 3 passages through a 10 ml pipette. Cells were then centrifuged at 180×g for 10 min at +4° C. on a layer of BSA (3.5%) in L15 medium. The supernatant was discarded and the cell pellets were re-suspended in a defined culture medium consisting of Neurobasal (Invitrogen) supplemented with B27 (2%), L-glutamine (2 mM) and 2% of PS solution and 10 ng/ml of BDNF and 1 ng/ml of Glial-Derived Neurotrophic Factor (GDNF). Viable cells were counted in a Neubauer cytometer using the trypan blue exclusion test. The cells were seeded at a density of 40 000 cells/well in 96 well-plates (pre-coated with poly-L-lysine) and maintained in a humidified incubator at 37° C. in 5% CO2/95% air atmosphere. Half of the medium was changed every 2 days with fresh medium.
Treatment
On day 6 of culture, the medium was removed. The PAT peptide (10 mg) synthesized by Polypeptide (Denmark) was solubilized in distilled water. PAT (concentrations ranging from 0.1 nM to 1 μM) or BDNF (50 ng/mL i.e. 2 nM) were solved in culture medium (containing 0.1% DMSO) and then pre-incubated with mesencephalic neurons for 1 hour before the 6-OHDA application. One hour after test compound incubation, 6-OHDA was added to a final concentration of 20 μM diluted in culture medium still in presence of compound or BDNF for 24 hours. Each condition was tested on one culture mesencephalic dopaminergic neurons but 6 independent replicates.
End Point Evaluation: Measurement of Total Number of TH-Positive Neurons After 24 hours of intoxication, cells were fixed by a solution of 4% paraformaldehyde in PBS, pH=7.3 for 20 min at room temperature. The cells were washed again twice in PBS, permeabilized and non-specific sites were blocked with a solution of PBS containing 0.1% of saponin and 1% FCS for 15 min at room temperature. Then, cells were incubated with monoclonal anti-tyrosine hydroxylase (TH) antibody produced in mouse at dilution of 1/10,000 in PBS containing 1% FCS, 0.1% saponin, for 2 hours at room temperature. These antibodies were revealed with Alexa Fluor 488 goat anti-mouse IgG at the dilution 1/800 in PBS containing 1% FCS, 0.1% saponin, for 1 h at room temperature.
For each condition, 20 pictures per well were acquired (representing 80% of the total surface of the well) using ImageXpress (Molecular device) equipped with a LED at 10× magnification. All images were acquired with the same conditions. The number of TH-positive neurons was automatically analyzed using MetaXpress software (Molecular device). Data were expressed in percentage of control conditions (no intoxication, no 6-OHDA=100%) in order to express the 6-OHDA injury. All values were expressed as mean+/−SEM (s.e.mean) (n=6 wells per condition per culture).
Results
The results are depicted in FIGS. 5A and 5B . FIG. 5A shows quantitative representation of the effect of PAT on the survival of TH-positive dopaminergic neurons injured by 6-OHDA. FIG. 5B shows examples of microscopic aspect of mesencephalic neurons in control culture conditions, injured by 6-OHDA or pretreated with 10 nM PAT before 6-OHDA application.
As previously shown in the literature, the survival of TH-positive dopaminergic neurons exposed to 6-OHDA was reduced by 31% compared to cells maintained in control culture conditions. Pretreatment with BNDF neurotrophic factor fully protected TH-positive neurons from 6-OHDA-induced cell death.
Pre-incubation of dopaminergic neurons with PAT resulted in a dose-dependent protection against 6-OHDA injury. 100% survival levels were achieved with a concentration of PAT as low as 10 nM. Under these conditions PAT was as potent as BNDF.
The potent neuroprotective activity of PAT was obvious when looking at the microscopic aspect of dopaminergic neurons as illustrated in FIG. 5B . Exposure to 6-OHDA resulted in a strong reduction of TH-positive neurons per well compared to control culture conditions due to cell death. Treatment with PAT restored the number of viable TH-positive neurons per well to a level similar to control conditions.
Example 4
Cellular Model of Huntington's Disease— Survival of Rat Primary Gabaergic Medium Spiny Neurons after Glutamate Injury
GABAergic medium spiny neurons (MSNs) in the striatum represent the mostly affected cell population in HD brain. Being the main neuronal cell type of the striatum (85% in humans), GABAergic MSNs play a central role in the clinical manifestation of HD. GABA is viewed as the neurotransmitter that inhibits spontaneous involuntary movements, therefore loss of GABAergic MSNs is responsible for chorea development and other involuntary movements. The exquisite vulnerability of MSNs of striatum to degeneration in HD is caused by glutamate excitotoxicity that leads to neuronal dysfunction and death. Excessive activation of NMDA glutamate receptors is observed in post-mortem HD brain tissue (Kumar P. et al. Pharmacol. Rep. 2010; 62: 1). Because glutamate is toxic to GABAergic striatal neurons in vitro, it provides a useful model of HD (Freese A et al. Brain Res. 1990; 521: 254). In this in vitro test, GABAergic MSNs are exposed to glutamate injury. Neuroprotective effect of a test compound is evaluated by pre-incubating MSNs for 1 h before the glutamate application. After 24 h of intoxication, viable GABAergic neurons are visualized and quantified by staining with a monoclonal anti-Glutamic Acid Decarboxylase antibody (specific for isoform GAD67). Glutamic acid decarboxylase is the first and rate-limiting enzyme involved in the biosynthesis of GABA from glutamic acid in higher brain regions. Brain derived neurotrophic factor (BDNF) is used as a positive control given that it has been identified as a factor required for the maturation and survival of MSNs (Ivkovic S et al. J. Neurosci. 1999; 19: 5409).
Experimental Protocol:
The information relative to the preparation of mesencephalic rat neurons, the culture conditions and treatment of cells are similar to those of Example 3.
Treatment
On day 13 of culture, the medium was removed. The PAT peptide (10 mg) synthesized by Polypeptide (Denmark) was solubilized in distilled water. PAT (concentrations ranging from 0.1 nM to 1 μM) or BDNF (50 ng/mL i.e. 2 nM) were solved in culture medium (containing 0.1% DMSO) and then pre-incubated with MSNs for 1 hour before the glutamate application. One hour after test compound incubation, glutamate was added to a final concentration of 10 μM diluted in culture medium still in presence of compound or BDNF for 20 min. After 20 min, glutamate was washed and fresh culture medium with BNDF or test compound was added for additional 24 h. Each condition was tested on one culture mesencephalic GABAergic neurons but 6 independent replicates.
End Point Evaluation: Measurement of Total Number of GAD67 Positive Neurons
After 24 hours of intoxication, cells were fixed with a cold solution of ethanol (95%) in acetic acid (5%) for 5 min. The cells were washed again twice in PBS, permeabilized and non-specific sites were blocked with a solution of PBS containing 0.1% of saponin and 1% FCS for 15 min at room temperature. Then, cells were incubated with monoclonal anti-GAD67 antibody produced in mouse at dilution of 1/200 in PBS containing 1% FCS, 0.1% saponin, for 2 hours at room temperature. These antibodies were revealed with Alexa Fluor 488 goat anti-mouse IgG at the dilution 1/400 in PBS containing 1% FCS, 0.1% saponin, for 1 h at room temperature.
For each condition, 30 pictures per well were acquired (representing 80% of the total surface of the well) using ImageXpress (Molecular device) equipped with a LED at 20× magnification. All images were acquired with the same conditions. The number of GAD67-positive neurons was automatically analyzed using MetaXpress software (Molecular device). Data were expressed in percentage of control conditions (no intoxication, no glutamate=100%) in order to express the glutamate injury. All values were expressed as mean+/−SEM (s.e. mean) (n=6 wells per condition per culture).
Results
The results are depicted in FIGS. 6A and 6B . FIG. 6A shows quantitative representation of the effect of PAT on the survival of GAD67-positive neurons injured by glutamate. FIG. 6B shows examples of microscopic aspect of GAD67-positive GABAergic MSNs in control culture conditions, injured by glutamate or pretreated with 10 nM PAT before glutamate application.
As expected, the survival of GAD67-positive MSN exposed to glutamate was reduced by 38% compared to cells maintained in control culture conditions. Pretreatment with BNDF neurotrophic factor protected GAD67-positive neurons from glutamate-induced cell death to some extent (81% cell survival).
Pre-incubation of GABAergic neurons with PAT resulted in a dose-dependent protection against glutamate injury. Survival levels above 90% were achieved with concentrations of PAT starting from 10 nM. PAT was in average more potent than BNDF in tested conditions.
The potent neuroprotective activity of PAT was obvious when looking at the microscopic aspect of GABAergic neurons as illustrated in FIG. 6B . Exposure to glutamate resulted in a strong reduction of GAD67-positive neurons per well compared to control culture conditions due to cell death. Treatment with PAT restored the number of viable GAD67-positive neurons per well to a level similar to control conditions.
Thus the use of established cellular models of Parkinson's and Huntington's disease shows that PAT exerts a potent protective effect on injured neurons. In addition, PAT reduces cognitive decline in a mouse model of Alzheimer's disease. All together this peptide proves to be an interesting and promising candidate to treat and prevent neurodegenerative disorders with highly unmet medical needs. | A PAT nonapeptide of formula EAKSQGGSD (SEQ ID NO: 1) can be used to treat or prevent neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease and amyotrophic lateral sclerosis. Pharmaceutical compositions containing the PAT nonapeptide can be formulated for administration by parenteral route, including the subcutaneous, intraperitoneal, intravenous or intranasal routes. | 0 |
TECHNICAL FIELD
[0001] The present invention relates to a balloon assembly particularly for valvuloplasty applications.
BACKGROUND ART
[0002] Valvular stenosis is a defect which may be congenital, developing in the foetus and present at birth, or may develop over time, for instance as an effect of some other disorder. For example, mitral valve stenosis in adults is rarely congenital and can occur as a result of rheumatic fever or calcium obstruction in the valve.
[0003] Congenital valvular stenosis is found in around one in every 1,000 newborns. In some instances health problems affecting the mother during pregnancy is thought to contribute to the defect. About 5% of all cardiac defects are found to relate to valvular stenosis. Valvular abnormalities are found in children of both sexes, but the vast majority of adult valvular stenosis is found to occur in men. Most adults with Mitral stenosis are women who have suffered rheumatic fever as children.
[0004] Reduced valvular function is also experienced in some patients, caused by the valves failing to open fully.
[0005] A variety of treatments have been attempted to treat these conditions, including diuretic therapy, anticoagulant therapy and open surgery. More recently, however, balloon valvuloplasty has been performed, both on children and on adults. The procedure is to force the valve open, with the aim that so doing will cure the stenosis and prompt normal valve function. In balloon valvuloplasty, a small balloon tipped catheter is positioned within the valve opening and the balloon then inflated to prise the valve leaflets apart. The balloon has to have an inflated diameter no greater than the diameter of the valve seat in order not to damage the valve. The balloon is then deflated and removed.
[0000] In order not to cause trauma or damage to the heart, balloon valvuloplasty must be performed quickly.
[0006] Often, balloon valvuloplasty can sure the valve function and thus avoid the need for open heart surgery and valve replacement. It is therefore seen as an important method of treatment.
[0007] There is a risk, however, during balloon valvuloplasty that the balloon catheter jumps or slips out of position either out of the heart or into the heart, as a result of heart/valve function as well as of the dynamics of the inflating balloon. Such slippage can either lead to an abortive procedure or to damage of the heart.
[0008] Balloon catheter assemblies for a variety of treatments have been disclosed in WO-03/039,628, U.S. Pat. No. 6,129,706, U.S. Pat. No. 7,008,438, EP-0,204,218, US-2005/0,075,662, US-2006/0,167,407, US-2009/0,005,732, U.S. Pat. No. 5,395,331, U.S. Pat. No. 5,720,726, U.S. Pat. No. 5,423,745 and U.S. Pat. No. 7,566,319.
DISCLOSURE OF THE INVENTION
[0009] The present invention seeks to provide an improved balloon catheter for valvuloplasty procedures.
[0010] According to an aspect of the present invention, there is provided a balloon catheter assembly including an inflatable balloon provided with a body portion having first and second ends and a longitudinal axis extending from the first end to the second end; the balloon being formed of balloon material; and at least one circumferentially extending rib element at or proximate one of said first and second ends, the rib element being formed of balloon material and being inflatable with the balloon; the rib element, when inflated, including a retaining shoulder facing the body portion of the balloon and a wall portion facing a direction opposite the body portion; wherein said retaining shoulder has an interior angle to the longitudinal axis which is greater than the interior angle of the wall portion to the longitudinal axis of the balloon; the rib element being discontinuous around the circumference of the balloon and being formed of a plurality of circumferentially aligned rib portions spaced from one another by a tether element.
[0011] The rib, which could be said to have a wedge shape when viewed in side elevation, acts to retain the balloon in position during inflation and use. The fact that the rib is inflatable allows the balloon to be wrapped to a small footprint and also allows the rib to be made larger and/or higher above the surface of the body portion when inflated than is possible with, for instance, solid ribs.
[0012] The discontinuities in the rib or ribs, providing tether elements between the rib portions, ensure that these do not flatten during inflation of the balloon. In the preferred embodiment, the or each rib is formed of at least three sections preferably of similar sizes to one another.
[0013] It has been found that such discontinuities also assist in the deflation of the balloon, in that they cause the balloon to collapse into the tethers or discontinuities, leaving wings where the rib portions are located. Specifically, the discontinuities or tethers will, on application of a vacuum to the balloon, be pulled inwardly towards the centre of the balloon and the ribs will generally fold along the length of the balloon. The balloon can then be readily wrapped, often without the need for a specialised wrapping tool.
[0014] Advantageously, the retaining shoulder has an interior angle to the surface of the body member which is at least 70 degrees, advantageously at least 80 degrees and in the preferred embodiment substantially 90 degrees.
[0015] The retaining shoulder may comprise all of or part of the portion of the or each rib facing the body portion of the balloon.
[0016] In the preferred embodiment, there are provided first and second ribs, located at or proximate the first and second ends of the body portion of the balloon, each of said first and second ribs having a retaining shoulder facing the opposing end of the balloon and a wall portion at or facing the end of the balloon at which the rib is located. The provision of two ribs of this nature can act to “lock” the balloon in position, for instance across a heart valve. Once inflated, the ribs ensure that the balloon is not able to slip out of position, in either direction of motion.
[0017] The or each rib preferably has an inflated height, measured from the surface of the body portion, of at least 0.5 millimetres, preferably between 0.5 millimetres and 4.0 millimetres. For a cardiac application, the rib or ribs may have an inflated height of 2.0 to 4.0 millimetres.
[0018] The rib or ribs are preferably formed of the same material as the body portion of the balloon and in the preferred embodiment are a continuation of the balloon wall, that is have a wall thickness which is the same or substantially the same as that of the balloon. This gives the ribs a compliancy which is consistent with that of the majority of the balloon and also allows the ribs to be formed in the same process as the remainder of the balloon, typically from raw tubing which is inflated in a mold to the final desired shape of the balloon. In this example, the mold would have impressions representative of the shapes, sizes and positions of the ribs.
[0019] In a practical embodiment, the balloon includes at least one intermediate rib extending circumferentially around the body portion, and in the preferred embodiment between the first and second end ribs. It is preferred, however, that there are provided two such intermediate ribs, spaced from one another and advantageously evenly along the body portion of the balloon.
[0020] Two, or an even number of intermediate ribs, can enable their positioning such that the centre point of the balloon is free of such ribbing. This can assist in locating the balloon at its centre point across, instance, a valve.
[0021] It is preferred, but not essential, that the or each intermediate rib has a height which is less than the height of the end rib or ribs.
[0022] The preferred embodiments are used in carrying out valvuloplasty treatment of the heart valves. The body portion preferably has an inflated diameter of around 18 to 25 millimetres.
[0023] The balloon is preferably made from a substantially non-compliant material such as Pebax, nylon 12, polyethylene, PET and polyurethane.
[0024] The balloon may be made of a single layer or of a plurality of layers useful, for instance, in optimising balloon strength, wrappability and the like.
[0025] The balloon is typically fitted to a catheter element, the latter provided with at least one lumen for inflating the balloon. The catheter element may also include other lumens, for instance for a guide wire, for the administration of contrast media and so on.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Embodiment of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which:
[0027] FIG. 1 shows an example of a human heart with a valvuloplasty balloon positioned across the mitral valve leading to the left ventricle;
[0028] FIG. 2 a is a side elevational view of an embodiment of valvuloplasty balloon;
[0029] FIG. 2 b is an end view of the balloon of FIG. 2 a;
[0030] FIG. 3 a is a side elevational view of another embodiment of valvuloplasty balloon;
[0031] FIG. 3 b is an end view of the balloon of FIG. 3 a;
[0032] FIG. 4 is a cross-sectional view, in side elevation, of a part of an example of mold for use in the production of a balloon as shown in FIG. 3 ;
[0033] FIG. 5 is a side elevational view of another embodiment of valvuloplasty balloon; and
[0034] FIG. 6 is a side elevational view of another embodiment of valvuloplasty balloon.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] Referring to FIG. 1 , there is shown in schematic form an example of a human heart 10 . The pulmonary veins 12 feed into the left atrium 14 and therefrom through the mitral valve 16 into the left ventricle 18 . The left ventricle 18 feeds into the aorta 20 for passage of oxygenated blood to the body. The superior and inferior venae cava 22 , 24 feed into the right atrium 26 and therefrom through the tricuspid valve 28 into the right ventricle 30 . The right ventricle 30 feeds to the left and right pulmonary arteries 32 , 34 respectively. The pulmonary arteries 32 and aorta have semi lunar valves 36 for controlling the direction of blood flow as the heart 10 beats.
[0036] As mentioned above, one or more of the valves 18 , 28 and 36 of the heart 10 may become defective, for example as a result of stenosis, reduced valvular function and other factors. The mitral valve 16 is particularly susceptible to reduced function and stenosis.
[0037] FIG. 1 shows a valvuloplasty balloon 40 located across the mitral valve 16 , having been fed endoluminally through the pulmonary veins. In this Figure, the balloon 40 is in a deflated state, ready to be deployed. In accordance with accepted valvuloplasty procedures, the balloon 40 is inflated rapidly, so as to prize open the valve leaflet of the valve 16 , up to or close to the maximum opening of the valve, that is close to the diameter of the valve seat. The forced opening of the valve 16 in this manner can cure stenosis or other causes of reduced valve function.
[0038] The valvuloplasty operation is typically carried out rapidly, that is the balloon 40 is rapidly inflated and the deflated so as to be removed from the patient. The stage of inflation of the balloon 40 , as well as the varying state of the heart 10 can cause the balloon 40 to jump or slip across the valve 16 as it is inflated. If the balloon 40 jumps forwards, the tip off the balloon catheter assembly risks piercing into the wall of, in this example, the left ventricle 18 . This can cause damage to the heart. Should the balloon 40 slip in the other direction, there is the risk that the balloon 40 will no longer be within the valve area and thus its inflation will fail to open the valve as desired.
[0039] Referring now to FIGS. 2 a and 2 b, there is shown an embodiment of balloon particularly suited for such valvuloplasty procedures. The balloon 50 includes a substantially cylindrical body portion 52 bounded by first and second conical portions 54 , 56 , each of which tapers to a respective neck portion 58 , 60 . The neck portions 58 , 60 are sized so as to fit firmly and in a fluid tight manner to a carrier catheter 62 (as seen in FIG. 1 ). As is known in the art, the carrier catheter 62 includes at least one lumen with an opening within the balloon 50 to allows inflation and deflation fluid to flow into and out of the balloon 50 . The carrier catheter 62 may also include other lumens, such as one for a guide wire (not shown).
[0040] The conical end portions 54 , 56 are provided, in this embodiment, with raised circumferential shoulders or ribs 64 , 66 , which have a radial dimension or height which is greater than the radius of the body portion 52 . As a result, the shoulders 64 , 66 provide a retaining wall 68 which, in the preferred embodiment, is at an interior angle (that is the angle characterising the rotation of the line defining the balloon wall, through the bulk of the balloon, to the longitudinal axis) of at least 70 degrees relative to the line of the body portion, more preferably at least 80 degrees and most preferably around 90 degrees. The shoulders 68 end in a chamfered portion 70 which is preferably rounded. Thus, it is to be understood that only a portion of the shoulders 64 , 66 may have these angles.
[0041] As can be seen in FIG. 2 a, the conical wall of the portions 54 , 56 has an interior angle of around 25 degrees in this embodiment, against an interior angle of close to 90 degrees for the retaining shoulders 68 .
[0042] The shoulders 64 , 66 preferably have a height of at least 0.5 millimetres and preferably of between 0.5 to 4.0 millimetres when inflated. Such a height will enable the shoulders 64 , 66 to provide effective retention of the balloon 50 across a valve.
[0043] The provision of rear or opposing walls to the ribs 64 , 66 , in this case the conical walls of the ends 54 , 56 , which have a shallower angle enables the balloon 50 , should it be necessary, to be pushed or pulled into the zone of a valve, with the valve sliding up the shallow angle of these walls, and into position across the cylindrical portion 52 of the balloon 50 . Once in this position, the shoulders 64 , 66 prevent the slippage of the balloon out of position.
[0044] The balloon 50 is made in this embodiment from a substantially consistent and unitary layer of material, including the shoulders 64 , 66 . It is to be understood that the layer could be formed as a sandwich of a plurality of sub layers if desired. As a result, the shoulders 64 , 66 are inflatable to the shape shown in FIGS. 2 a and 2 b and thus collapsible when the balloon 50 is deflated.
[0045] The shoulders 64 , 66 are not continuous around the entire is circumference of the balloon 50 and instead preferably segmented into a plurality of part circular segments 72 , as can be seen in particular in FIG. 2 b. Between adjacent segments 72 there are provided zones 74 which could be described as tethers. These zones 74 have, in this embodiment, dimensions similar to those of the body portion 52 and could be described as extensions of the body portion 52 , extending to the conical ends in such a manner that the tethers 74 has the same diameter as the body portion 52 . The tethers limit the amount by which the balloon 50 can inflate, particularly at the interface between the body portion 52 and the conical ends 54 , 56 . Thus, inflation of the balloon 50 cannot stretch the shoulders 64 , 66 to an extent which would cause these to flatten. In the absence of such tethers 74 , the balloon 50 would continue to expand until the shoulders 64 , 66 become substantially flattened and therefore lose their features.
[0046] The number of segments 72 can be a matter of preference and choice. In the preferred embodiment, each shoulder 64 , 66 is formed of four segments 74 .
[0047] In other embodiments, the balloon 50 could be provided with internal tethers to maintain the integrity of the shoulders 64 , 66 . These embodiments are not, however, preferred.
[0048] In the embodiment shown in FIG. 2 a the balloon 50 has a length of around 97 mm and an overall width of its cylindrical portion 52 of around 22 mm. The cylindrical portion 52 has a length in the region of 30 mm and is designed specifically for the treatment of a mitral valve such as the valve 16 shown in FIG. 1 . The neck portions have a typical length of around 10 mm, in order to provide good sealing to the carrier catheter 62 . The neck portions 58 , 60 also have a diameter in the region of 4 mm, which is about the same as the diameter of the carrier catheter 62 . As can be seen, in this example, the conical end portions 54 , 56 taper at an interior angle of 25° to the longitudinal axis of the balloon 50 . These are preferred dimensions for the specific medical application to which they are intended, that is the treatment of an adult valvular procedure. It will be apparent, however, that the dimensions of the balloon 50 will vary, both in terms of overall scale and in terms of length and diameter in dependence upon the particular medical application. As explained above, for instance, it is important that the balloon 50 should inflate to no more than the diameter of the valve seat of the particular valve to be treated. Similarly, the length of the balloon although being dependent large part upon the dimensions of the valve and also the space available for the balloon.
[0049] Referring now to FIGS. 3 a and 3 b, there is shown another embodiment of balloon assembly 100 which has the same characteristics and features of the embodiment of FIGS. 2 and 2 a and described above, with the addition of intermediate ribbing 102 located on the cylindrical portion 52 of the balloon 100 . In this embodiment, there are provided two additional rib elements 102 , which are equally spaced along the cylindrical portion 52 of the balloon 100 . In this example, the ribs 102 leave the centre of the cylindrical portion 52 free of any intermediate ribbing. However, the number and position of intermediate ribs 102 can be different from those shown in FIG. 3 a. For instance, there can be provided just a single intermediate rib 102 or more than 2 and these could be spaced non-symmetrically along the cylindrical portion 52 of the balloon 100 . In this embodiment, the intermediate ribs 102 have a width of around 2 mm and a height of around 0.5 to around 1.0 mm when inflated. The intermediate ribs 102 preferably have symmetrical side walls, that is walls which are at equal but opposing interior angles to the longitudinal axis of the balloon 100 , as opposed to the asymmetric arrangement of the end shoulders 64 , 66 . The intermediate ribs 102 provide additional securing of the balloon 100 during its use and in particular can prevent the balloon 100 from sliding when located within a valve.
[0050] As with the shoulders 64 , 66 , it is preferred that the intermediate ribs 102 are inflated from conventional balloon wall material, that is that they are not solid elements, although the latter is a possible alternative as is providing the intermediate ribs 102 as separate elements which are fixed to the balloon wall. In the preferred embodiment, the intermediate ribs 102 are also discontinuous and may be in four separate sections, consistent with and aligned with the section 72 following the end shoulders 64 , 66 . Similarly to the shoulders 64 , 66 , the intermediate ribs 102 are separated from one another by tethers 104 , which could be described as unmodified portions of the cylindrical section 52 of the balloon 100 . These tethers 104 limit the inflation of the balloon 100 and in particular of the cylindrical portion 52 to ensure that the intermediate ribs 102 do not flatten when the balloon 100 is inflated.
[0051] Even though the embodiment shown in FIGS. 3 a and 3 b has intermediate ribs 102 which have the same number of sections as the end shoulders 64 and 66 and tethers 104 which are aligned with one another with respect to the adjacent ribs 102 and aligned with the tethers 74 of the end sections 64 , 66 , this is not necessarily the case. The various sections forming the end shoulders 64 , 66 and the intermediate ribs 102 can be circumferentially non-aligned and this can also apply with respect to the end shoulder 64 , 66 of the embodiment of FIGS. 2 a and 2 b.
[0052] Referring now to FIG. 4 , there is shown in schematic form a view of a part of a mold 120 for forming the balloon 100 of the embodiment of FIGS. 3 a and 3 b. The mold 120 , which would typically be formed of a plurality of sections which are connected to one another, provides an internal surface 122 which has a contour equivalent to the contour of the balloon 100 when this is fully inflated. In other words, the contour 122 has grooves and recesses that are shaped to accommodate the various features 52 - 104 of the balloon 100 . In this manner, when a raw tubing for the formation of the balloon 100 is inserted within the cavity of the mold 120 and inflated, the raw tubing is inflated against the wall 122 to keep or develop the shape of the various features of the balloon 100 . As the balloons contemplated herein can be formed by known techniques, it is not necessary to describe in detail the method of their manufacture.
[0053] Although the shoulders or ribs 64 and 66 are, in the embodiments of FIGS. 2 and 3 , shown to be integral with the conical segments 52 , 54 of the balloon 50 , this is not necessary. In other embodiments, the ribs 64 , 66 could be located on the cylindrical portion 52 of the balloon 50 , adjacent but not part of the ends 54 , 56 . In this embodiment, the ribs would still have the feature of providing a substantially “vertical” retention wall facing the longitudinal centre point of the balloon 50 and walls on their opposite sides which has a shallower angle.
[0054] The balloon 50 is preferably made of a substantially non-compliant material such as Pebax, nylon 12 , polyethylene, PET and polyurethane. By substantially non-compliant it is meant that the balloon will inflate to a reliable and substantially consistent diameter at a given inflation pressure.
[0055] FIGS. 5 and 6 show other embodiments of balloon 100 ′ and 100 ″. The balloons in these embodiments are substantially the same as the embodiments described above and differ only in the shape of the body portion 153 , 252 . They thus have all of the features and elements of the above described embodiments and optionally also intermediate ribs.
[0056] In the embodiment of FIG. 5 the body portion 152 of the balloon has a waisted configuration, that is it narrows towards the longitudinal centre point of the balloon 100 ′.
[0057] The embodiment of FIG. 6 also has a body portion 252 which s narrows towards the longitudinal centre of the balloon but in this case the body portion includes a central portion 254 which is substantially cylindrical.
[0058] It is considered that the embodiments of FIGS. 5 and 6 are particularly advantageous in valvular applications as they can ensure that the balloon 100 ′, 100 ″ sits with its middle across the valve itself. | A valvuloplasty balloon assembly includes a balloon ( 50 ) provided with end shoulders ( 64, 66 ) preferably integral with end cones ( 54, 56 ) of the balloon ( 50 ). The end shoulders ( 64, 66 ) provide a substantially perpendicular stop shoulder ( 68 ) at either end of the cylindrical portion ( 52 ) of the balloon ( 50 ). The restraining shoulders ( 64, 66 ) act to hold the balloon ( 50 ) within a valve ( 16 ) of a heart ( 10 ), for instance. This prevents unwanted slippage of the balloon ( 50 ) during a valvuloplasty procedure and thus prevents possible damage caused as a result of such slippage. | 0 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 10/676,227 filed Sep. 30, 2003 (Attorney Docket No. BOR-161) entitled “Automatic Context Management For Web Applications With Client Side Code Execution,” which claims priority to U.S. Provisional Patent Application No. 60/431,055 filed Dec. 5, 2002 (Attorney Docket No. BOR-161P) entitled “Automatic Context Management For Web Applications With Client Side Code Execution,” which is incorporated herein by reference for all purposes.
FIELD OF THE INVENTION
[0002] The present invention generally relates to the field of computer applications and systems, and more specifically to a method and apparatus for testing, monitoring, and automating network applications and other fields where web client simulations are used.
BACKGROUND
[0003] Testing, monitoring, automation, and other web client simulation tools, consecutively called simulation tools, often use a recorder to automatically generate scripts that simulate user activity for repeated replay. For example, load testing tools can simulate large numbers of users using multiple technologies and allow businesses to predict the behavior of their e-business web application before it is introduced for actual use, regardless of the size and complexity of the application. A reliable load testing tool can simulate the activities of real users of various profiles who use web clients such as web browsers to access the web server. The load testing tool can simulate the activities of a maximum expected number of users, maintain a steady number of users over a certain period of time, or stress a single component of the web application. The load testing tool measures performance, reliability, accuracy and scalability and as such can reveal a wide range of possible errors. The load testing tool simulates real users by using virtual users that effect client-server interaction on the protocol level, not the graphical user interface (GUI) level. By performing a load test, businesses can test the performance, scalability, and reliability of the web application.
[0004] A load testing tool for web applications includes a controller, multiple agents, and multiple virtual users. The controller manages and monitors the load test. The agents are connected to the controller and run on the same computer as the controller or on remote computers. Each agent hosts multiple virtual users. Each virtual user makes requests to and receives responses back from the web application on the web server. The request contains the URL of the document to be retrieved from the server, and the response contains the document itself and information about the type of document. The document can be, for example, an HTML document, an image, a PDF file, a JavaScript file, or a plain text file.
[0005] A simulation tool incorporates a replay engine which simulates virtual users 608 with respect to the network traffic they generate 609 , as shown in FIG. 6 . A script 604 is a series of instructions which are input to the replay engine and can be in any format the replay engine understands (e.g., textual script written in a programming language, instructions stored in a database, or XML). A script can be written using a software tool like a text editor.
[0006] However, the most convenient way of generating a script is to use a recorder 602 which generates scripts 604 based on the HTTP(S) transactions 601 resulting from a real user using the web application. The recorder records into one or more scripts the actions of the real user such as clicking on hyperlinks, submitting forms, transitioning back and forth in the session history (e.g. using a web browser back button), and pausing between activity.
[0007] The recorded scripts are then replayed simultaneously to simulate the user interactions of many users in order to test the server. The scripts for each virtual user are executed concurrently by the replay engine to generate the desired load on the test environment. Each component of the test environment can be monitored in real-time during the load test replay to allow the testers to view the web application's performance at any time. The results of the load test replay can be analyzed to improve weaknesses and address errors in the web application. The scripts can be rerun to verify the adjustments.
[0008] Real users interact with a web application using a client program on a computer 101 that calls upon services provided by a server program as shown in FIG. 1 . The client program can be a web browser that requests services from a web server 102 , which in turn responds to the request by providing the services. This interaction is in the form of HTTP requests 103 and responses 104 .
[0009] Virtual users do not interact with the web application using a client program since this would involve running a client program for each individual virtual user. Running separate client programs for each virtual user is impractical for a load test because it wastes resources. Instead, the interactions of each virtual user with the web server take place on the protocol level. Therefore, in conventional load testing tools, the scripts display user interactions in the form of HTTP requests. The recorder records network activity between the client application and the server. Recorders used in load testing do not record activity within the client application such as the movement of each user's mouse or the specific keystrokes that each user performs.
[0010] A web page, as shown in FIG. 2 , includes one or more documents received from the web server. Each document is received by sending one HTTP request (or more than one request when there are redirections). A web page forms a tree which has a root document 201 and leaves. A root document is a document that can have one or more embedded sub-documents 202 , 203 such as HTML documents, images, embedded objects, frames, scripts, applets, and style sheets. Leaves 204 are documents, such as images, style sheets, and plain text, that cannot have sub-documents. The visual representation of a web page is exactly what the real user sees when using the web browser. Documents can also contain hyperlinks 205 and forms 206 , which are not separate documents. A user can click on a hyperlink to transition to another web page having the URL associated with the hyperlink. Forms can be completed and submitted to the server by the user, thereby causing a transition to another web page having the URL associated with the form. Web pages can also include executable code that is executed by the web browser (e.g. JavaScript, VBScript, and Java applets). The executable code can be embedded in HTML documents or contained in sub-documents.
[0011] FIG. 5 shows a session history, which is a sequence of web pages that are downloaded or retrieved from a client side cache. The interaction of the user with the web application is called a user session. The session begins when the user starts the browser and navigates to the web application. The session ends when the user closes the browser or navigates to a different web application. The URL of the first page 501 is specified by the user, e.g., by entering the URL in the address bar of the browser 511 or by clicking on a “bookmark”. Each successive page 502 , 503 , 504 , 505 is the result of a page transition from one page to the next page. A page transition can be caused by the user clicking a hyperlink 512 , the user filling in and submitting a form 513 , by the user navigating in the browser's page history by clicking the “back” or “forward” button 514 , or by the browser executing client side code 515 .
[0012] Although the HTTP protocol is a stateless protocol, complex web applications need to be able to relate a single request to one or more preceding requests. Such requests are common in web applications that use session IDs, shopping carts, user IDs, and other forms of state information. These forms of state information can be in the form of unique strings of characters that are placed in requests or responses, as well as the transferred documents such as HTML. The unique string appears hard-coded in each related request and response. Real clients such as web browsers can correctly identify state information in responses and can also correctly embed such state information in subsequent requests.
[0013] For example, a session ID is a unique string of characters that a web application assigns to all responses within a period of time in which a client and a server interact. The client then returns the session ID within a request to the server so that the web application can determine which client sent the request. A shopping cart is commonly used in e-business applications to handle catalogs of items that an individual user would like to purchase. User IDs are assigned by a web application to identify a particular user. If a simulation tool cannot correctly identify a session ID, a shopping cart ID, a user ID, or other forms of state information within a response and transfer it back to the server in subsequent requests, the simulation tool does not correctly simulate real clients. This may lead to invalid test results or even errors which in fact are not errors of the web application but rather an artifact of the simulation tool being unable to simulate real clients properly.
[0014] Conventional load testing tools can only handle standardized state information called cookies. All other forms of state information can, if at all, only be handled by manually customizing the script.
[0015] Context management is the ability of a testing tool to: a) manage state information during replay by dynamically analyzing content for state information, even when the content is generated dynamically and contains state information; b) properly transfer this state information back and forth in requests and responses; c) restructure received documents (one or more HTTP(S) transactions) into web pages; and d) maintain a session history to allow virtual users to transition back and forth between web pages in the session history.
[0016] Missing or poor context management of a simulation tool can result in the mishandling of state information which ultimately can lead to a failed, unreliable, and ineffectual load test. For example, when multiple virtual users log into the same account or session due to incorrect state management, the load on the web application does not correctly model the real intended behavior of the live application. Accurate simulation/testing tools would create one session per virtual user. Poor context management of a load testing application, in particular, can lead to inaccurate test results or failed tests. Missing automatic context management by the simulation tool must be compensated by large efforts to customize scripts manually for correct state management, thereby resulting in high costs and lost revenue.
[0017] State management may be achieved using state information which can be included as a unique string in cookies, URLs of links or embedded objects, or form fields. The string acts as a session ID or other ID such as an encryption ID or a serialized object reference to an object residing at the server which is placed in a hidden field. The string allows the server to identify the unique web session in which the original request originated or other state information, and the string is returned by the browser to the server as part of any subsequent request, thus relating the requests.
[0018] In a simulation tool without state management, the hard-coded session ID is sent to the server when replaying the script. However, since the specific session ID does not correctly identify the replayed session, this replay does not run correctly. The session ID only identifies the session ID of the recorded session and cannot be used again for the replayed session. Therefore, a script that uses such state information is unsuitable for a proper load test, and the web application will most likely generate errors during replay since sessions are usually terminated by the web server after a predetermined period of time. Load testing tools without state management generate scripts that must thus be customized, manually or via a tool, to handle state information such as session IDs in web applications in order to avoid such problems.
[0019] Conventional simulation tools use a HTTP-level replay or a page-level replay to execute scripts. A low-level, HTTP-level replay executes script instructions that specify single HTTP transactions. The information for each HTTP transaction, such as the URL and form data, is specified in the script. Because of this, session information, which is part of these URLs, and form data are hard-coded in the script and are not dynamically parsed out of documents during runtime. A HTTP-level API is therefore not suited for automatic state management and does not provide context management as well.
[0020] In contrast, a conventional simulation tool with a page-level replay executes script instructions that specify complete web pages that can include various images and frames to be downloaded. The replay engine uses a document parser (e.g. HTML parser) to obtain the URLs referencing embedded objects and frames at replay time. Since downloading a single web page using the page-level API automatically initiates HTTP requests for also downloading embedded objects or frames, the page-level script is typically shorter than the HTTP-level script. The page-level script can also automatically obtain state information which may be contained in URLs referencing frames and embedded objects in real time. Such state information is contained in URLs embedded in HTML tags of HTML documents and parsed in real time, but is not hard-coded in the page-level script.
[0021] The present invention includes a recorder which is able to identify the context of web page transitions by analyzing the HTTP(S) network traffic even for web applications that use client side code execution. Conventional recorders can also record context-full page-level scripts for web applications without client side code, but fail in many cases to do so if the web application uses client side code.
[0022] Both a web browser and the replay engine of a conventional simulation tool that is capable of a page-level replay follow the same steps when downloading a web page from a web server. Documents are downloaded (step 401 ) by the client from the server as shown in FIG. 4 , starting with the root document. If a downloaded document is parsable (step 402 ) (e.g. an HTML document), a standard HTML parser parses the document (step 404 ). A standard HTML parser parses each HTML document as it is received by the client from the web server so that embedded objects and frames can be detected and downloaded automatically. Since the conventional page-level API function call requests all embedded objects and frames in the root document, the standard HTML parser specifically looks for these embedded objects and frames in the HTML document. The standard HTML parser also looks for hyperlinks and forms in the HTML document so that they can be referenced in subsequent API calls when transitioning between web pages.
[0023] As shown in FIG. 3 , the standard HTML parser 302 parses an HTML document 301 and can output a list of frames 311 , a list of embedded documents 312 , a list of hyperlinks 313 , and a list of forms 314 , each with their associated URLs. Each embedded object and frame is downloaded following the same procedure of FIG. 4 in a recursive way. A document that is not parsable stops the recursion (step 403 ).
[0024] The conventional recorder uses the HTML parser to analyze the HTML documents wherein a single HTML document is retrieved by one (or more when there are redirections) HTTP requests. Conventional recorders save some state information hard-coded in the API call parameters in the script.
[0025] Page-level replay instructions can be “context-full” or “context-less”, depending on how a page transition is specified by the replay instruction. A “context-less” replay instruction can be executed by the replay engine using information only specified in the script. A context-less replay instruction includes the URL of the root document to download and optional replay instructions that send form data without referring to a form contained in a previously downloaded web page. Both the URL and all form field names and values are specified in the script, possibly containing hard-coded state information.
[0026] The term “context-less” refers to the fact that the replay engine can execute such a replay instruction without using the context of the user session executed so far. No references to previously downloaded web pages in the user session exist, and no dynamic data from previously downloaded web pages is used.
[0027] A “context-full” replay instruction is a replay instruction which refers to a previously downloaded page. The term “context-full” refers to the fact that the replay engine can execute the replay instruction only within the context of the replay session up to the point where the context-full replay instruction is executed. Without a session history, the replay engine would not be able to collect the data needed to perform a context-full replay instruction.
[0028] The replay engine identifies the HTML document and all of the information associated with the particular HTML document such as the embedded images and frames that form the HTML document. All of the information is downloaded in real-time during the replay. There are no session IDs hard-coded in the script.
[0029] For example, a replay instruction can download a web page by following a hyperlink contained in the previously downloaded web page. To download the web page, the replay engine uses the document parser to obtain the URL that is associated with that hyperlink. The URL associated with the hyperlink is obtained in real-time during the replay. The script only contains the reference to the hyperlink, but not the URL, which might contain state information. A reference to a hyperlink may consist of several items, e.g., name of the hyperlink, ordinal number, name of containing frame, reference to the containing web page. These types of references typically do not contain state information.
[0030] In another example, a replay instruction submits a form which is contained in a previously downloaded web page, given a reference to that form. The replay engine uses the document parser to obtain the URL associated with the form, and the names and initial values of the form fields. The script only contains the name of the form and the values of form fields that are different from the original values (i.e. the values that have been edited by the user). The script does not contain the URL, which may contain state information. The script also does not contain the values of hidden or otherwise unchanged form fields, which also may contain state information. A reference to a form may consist of several items, e.g., name of the form, ordinal number, name of containing frame, reference to the containing web page. These types of references typically do not contain state information.
[0031] The page-level script can eliminate many of the URLs that contain state information since usually the URL for the first HTML document is the only URL hard-coded in the script. The URL typically corresponds to the first page specified by the virtual user and typically does not contain state information since it is the entry point to the web application. The other links are obtained dynamically during the replay as URLs which are obtained by parsing the downloaded HTML document during replay. These links correspond to context-full replay instructions in the script. By obtaining information dynamically, the use of hard-coded session IDs in the script can be avoided.
[0032] The capability of the replay engine for automatic state management by means of executing context-full replay instructions is called automatic context management. A page-level replay is suited for automatic context management for web applications that do not use client side code execution, i.e., each page transition is implemented by standard hyperlinks and form submissions.
[0033] The term “client side code execution” refers to code executed within the web browser by the client such as JavaScript code embedded in HTML documents or in separate JavaScript documents, Java applets, VBScript, ActiveX controls, or browser plug-ins.
[0034] Code executed on the client side may dynamically assemble URLs and forms and cause page transitions using these URLs and forms. Such page transitions cannot be modeled by context-full replay instructions within a traditional page-level replay, because the URLs and forms may not correspond to any hyperlink or form contained in any previously downloaded web page.
[0035] The standard page level recorder/replay is sufficient for web applications that interact with client programs using standard HTML documents. However, a standard page level recorder/replay using a standard HTML parser is unable to parse code executed on the client side since it is unable to recognize URLs in the client side code. These URLs are recorded into the script, and this leads to errors during replay if these URLs contain hard-coded state information.
[0036] For a successful record/replay, the virtual users simulated by the testing tool need to behave similarly to a web browser. For instance, a real user downloads a JavaScript document referenced by an HTML document and executes the JavaScript when the page is viewed in the web browser. The JavaScript code can generate a direct HTTP request to the server. However, URLs included in JavaScript code that is executed on the client side are not recognized by a standard HTML parser since they do not appear as standard links, frames, forms, and embedded objects. If there is a URL coded in the JavaScript, that URL is not recognized by a standard HTML parser so that the Page Level API could use this parsed URL (which might contain state information) for a contextful page transition or automatic load of an embedded object or frame. It is instead recorded as is, leading to context errors during replay.
[0037] The inability of the standard HTML parser to parse code such as JavaScript or applets makes it difficult to model accurately the interactions between the web application and the virtual users in a page-level API. Recorders of typical simulation tools may not be able to properly record context-full functions when code is executed on the client side and will record context-less functions instead.
[0038] The recorder cannot determine the context of an API function when it observes an HTTP request that cannot be interpreted as an embedded object, a frame, a link, a form, or any other entity that the standard HTML parser can detect. The standard HTML parser does not have the ability to identify the URLs generated during client side code execution. Therefore, the recorder records context-less function calls corresponding to the non-interpreted HTTP request.
[0039] The standard HTML parser cannot recognize a URL that is generated by executing client side code and therefore cannot associate the URL of the recorded HTTP transaction with any URL in the session history. Therefore, the recorder records a hard-coded URL in the API function call.
[0040] The scripts that are generated by a recorder using a standard HTML parser produce an unreliable load test replay when the replay engine executes a context-less replay instruction using hard-coded state information. The standard HTML parser is only able to identify URLs found in HTML tags such as hyperlinks and references to frames and embedded objects.
[0041] Client-side code causes actions that are performed by the client, rather than by executing web application code on the server. Code executed on the client side gives web developers increased functionality over standard HTML techniques and provides the client side portion of the web application with abilities such as loading a web document, loading embedded objects, and modifying HTML code and form values.
[0042] Conventional load testing tools exhibit poor context management when the conventional page-level recorder generates context-less function calls after code is executed on the client side. When the replay engine executes the context-less function call, the state information contained in the context-less function call may generate errors in the replay. These errors are generally unrelated to the performance of the web application under a load test, thereby leading to failed or unreliable test results.
[0043] State information can be handled properly by driving a web browser during the load test for each individual virtual user. A scalable, high-performance load testing tool does not drive Web browsers and as such does not execute client side code since this wastes resources. Instead, a virtual user accesses a web page on the protocol level during a load test. Running separate client programs for each virtual user is also unnecessary since a load testing tool is intended to test the server and not the client. The execution of application code for each virtual user during the load test has a heavy impact on scalability and performance measurement accuracy. Therefore, execution of client side code is especially not an option for a simulation tool that aims to simulate thousands of virtual users on a single agent machine.
[0044] Conventional load testing tools also exhibit poor context management when handling hidden form fields and form fields that are modified, added, or removed using code executed on the client side. Web applications commonly use hidden form fields to transfer session information when users complete and submit forms to the web application. Also, JavaScript and applets are commonly used to modify, add, and remove form fields. The standard HTML parser overlooks state information which is carried or generated by JavaScript or applets. Since the standard HTML parser cannot identify dynamically adjusted hidden form field information in the HTML document without executing the client side code, the session information commonly found in hidden form fields cannot be removed from scripts and subsequently obtained dynamically in the replay. Instead, the state information remains as hard-coded information in the recorded scripts in context-less API function calls.
[0045] As shown in FIG. 13 , the recorder processes a HTTP transaction by inspecting the transaction (step 1301 ) using the session history 1302 to identify the role of the HTTP transaction within the session history.
[0046] If the HTTP transaction corresponds to an embedded object (step 1311 ), no replay instruction is added to the script. The session history is updated to reflect the fact that this embedded object has been downloaded.
[0047] If the HTTP transaction corresponds to a frame (step 1312 ), no replay instruction is added to the script. The session history is updated to reflect the fact that this frame has been downloaded.
[0048] If the HTTP transaction corresponds to a hyperlink (step 1313 ), a new context-full script instruction “FollowHyperlink” is recorded in the script along with parameters that allow the replay engine to reference the hyperlink during replay. A new web page is added to the session history resulting from following the hyperlink. However, this new web page in the session history is incomplete and will be populated with embedded documents and frames as the recorder processes the upcoming HTTP transactions.
[0049] If the HTTP transaction corresponds to a form submission of an existing form (step 1314 ), a new context-full script instruction “SubmitForm” is recorded in the script along with parameters that allow the replay engine to reference the form during replay and the names and values of the form fields that have been edited by the user. A new web page is added to the session history resulting from the form submission. However, this new web page in the session history is incomplete and will be populated with embedded documents and frames as the recorder processes the upcoming HTTP transactions.
[0050] If the HTTP transaction corresponds to neither a hyperlink nor a fowl submission, but contains form data (step 1315 ), a new context-less script instruction
[0051] “SendForm” is recorded in the script along with the complete form data that is to be used for sending the form during script replay, including the URL to use and the complete list of names and values of the form fields. A new web page is added to the session history resulting from the form submission. However, this new web page in the session history is incomplete and will be populated with embedded documents and frames as the recorder processes the upcoming HTTP transactions.
[0052] If the HTTP transaction corresponds to neither a hyperlink nor a form submission and does not contain form data (step 1316 ), a new context-less script instruction “LoadPage” is recorded in the script, along with the URL that is to be used for loading the page during script replay. A new web page is added to the session history representing the new web page. However, this new web page in the session history is incomplete and will be populated with embedded documents and frames as the recorder processes the upcoming HTTP transactions.
[0053] If the HTTP transaction corresponds to neither a hyperlink nor a form submission (steps 1315 and 1316 ), the recorder records context-less script instructions to the script. The way the conventional recorder handles these cases is the reason why hard-coded state information is incorporated in recorded scripts.
[0054] In a conventional recorder, each document in the session history is inspected to find forms that exactly match the form being submitted in order to find a form that can be used for a context-full SubmitForm replay instruction. Forms match exactly if the action URL (i.e., the URL that defines where to send the data in the submitted form when the submit button is clicked or a similar action is performed) is identical, and the form being submitted contains all form fields of the form from the document in the session history.
[0055] However, the faun being submitted may contain additional form fields not present in the form in the document in the session history. For instance, web browsers implicitly add the form fields “x” and “y” which contain the coordinates of the mouse click. Additionally, the form field values in the form being submitted may be different from the form field values in the form in the document in the session history because the user may have edited form field values, but the for his are considered identical since the form being submitted contains all form fields of the form from the document in the session history.
[0056] Only if an identical form is found, will the conventional recorder be able to record a context-full replay instruction such as “SubmitForm” with a reference to the form from the session history. If no such form is found in the session history, a conventional recorder records a contextless replay instruction such as “SendForm”, which also requires recording in the script a complete specification of the form without using any dynamic information.
[0057] Scripts can be customised by the tester after recording the script, manually or by using a software tool. However, this method of context management is complex, error-prone, and time-consuming and wastes quality assurance (QA) resources.
SUMMARY OF THE INVENTION
[0058] The present invention relates to a method and apparatus for providing automatic context management for simulating real users with virtual users for testing and monitoring web applications, including those web applications that execute code on the client side, without requiring the actual execution of client side web application code or the execution of the client within the testing, monitoring, or simulation tool. Simulation tools with automatic context management according to the present invention can record and replay context-full scripts that do not require manual customization and are capable of handling state information even for web applications that execute code on the client side. These scripts are able to realistically mimic complex web application sessions on the network HTTP layer.
[0059] The present invention includes a context-full page-level replay for a simulation tool that uses a scripting language to model end-user behavior causing network activity between a web application and a user's web browser (client), an extensible document parser, a recorder that automatically records context-full scripts, and a context-full replay engine which is able to execute the context-full page-level API calls. FIG. 2A illustrates a rear view of an exemplary nursing cover;
[0060] An enhanced, extensible document parser can parse URLs that standard HTML parsers would overlook. The extensible document parser searches the entire HTML document for standard and nonstandard embedded objects, hyperlinks, and forms. Nonstandard hyperlinks and forms can be embedded, for example, in JavaScript code in HTML documents or in Java applets. FIG. 3 illustrates an alternative frontal view of an exemplary nursing cover when worn;
[0061] The extensible document parser can locate URLs in a client side code. These URLs are detected during the script record process and recorded into the script without hard-coded state information. During the replay process, the otherwise hard-coded state information is obtained in real-time.
[0062] During the record process, if the recorder cannot associate a URL with a hyperlink, frame or form in the session history, the extensible document parser determines the appropriate parser extensions to be recorded into the script, so that the URL can be obtained dynamically during script replay.
[0063] For example, the parser extension can include a name for the link, a left boundary string, and a right boundary string. The left and right boundary strings specify the unique strings of characters that appear to the left and right of the URL, respectively. Using the left and right boundary strings, the extensible document parser can search for and detect the URL in any document. Whenever the left and right boundary strings appear in an HTML document, the extensible document parser identifies that the parsed URL located between the two strings corresponds to the link having the name specified in the parser extension.
[0064] The recorder records parser extensions into the script for use by the replay engine. The recorder records the name and boundary value fields in a parser extension in the script in an API function call so that the replay engine can parse the URL that otherwise could not be parsed. Each set of parser extensions is specific to a particular parsed URL and avoids the use of hard-coded URLs in the recorded script.
[0065] The extensible document parser parses for nonstandard embedded objects, hyperlinks, and forms to find URLs and forms that may contain session IDs and other forms of state information that a recorder using a standard HTML parser would include in the script.
[0066] The present invention includes form merging instructions for the replay engine. The form merging instructions are a method of describing how a form contained in a previously downloaded web page must be merged with a form defined in the script to obtain the form that must be submitted.
[0067] In the presence of client side code execution, the user may submit a form that does not correspond exactly to any form in the HTML web pages in the user session at that time. In addition to changing all HTML in a web page, JavaScript can modify HTML forms prior to submission by modifying form field values, modifying hidden fields, adding or removing form fields, renaming form fields, or changing the action URL.
[0068] The incorporation of code executed on the client side in the form submission can result in an API function that includes hard-coded state information such as session IDs in the script.
[0069] The present invention also includes a method of using a recorder to record scripts that use both a parser addition and form merging instructions so that the recorded result is a script capable of automatic context management, but does not contain hard-coded state information. The recorder can automatically choose parser additions, along with configuration parameters for the parser additions, from a library of available additions. The recorder chooses those additions that are needed for the web application being recorded.
[0070] The recorder can also automatically detect the faun in the user session that is most similar to a four being submitted, and generate form merging instructions into the script so that the replay engine will submit the correct form when executing the script. This recording process is called fuzzy form detection.
[0071] The replay engine follows the form merging instructions on how to merge the two forms to produce a form submission. The recorder generates these form merging instructions into the recorded script. The instructions specify which forms, form definitions, form fields, and alternate action URLs to use. The form is modeled using context-full faun functions for the form fields that incorporate state information.
[0072] The recorder does not need any pre-configuration before recording, no user intervention during recording, and the scripts do not need customization by the user after recording.
[0073] The recorder automatically records the scripts without the need for user customization or a separate configuration. No manual pre-configuration for specific handling techniques is necessary since the recorder can automatically adapt to formerly unknown situations. There is no need to manually add parsing instructions for state information to the script because there is no state information statically incorporated in the recorded script.
[0074] Automatic context management using an extensible document parser and fuzzy form detection and merging enables the automatic use of dynamic data in a script. No user configuration or customization is necessary before or after recording.
[0075] Automatic context management improves the ease-of-use and overall quality of a simulation tool and improves the productivity of the QA process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0076] FIG. 1 is a block diagram of the interaction between a client and a server;
[0077] FIG. 2 is a block diagram of the structure of a web page;
[0078] FIG. 3 is a diagram of a conventional document parser;
[0079] FIG. 4 is a flowchart of a method for downloading a web page from a web server;
[0080] FIG. 5 is a diagram of a sample user session;
[0081] FIG. 6 is a diagram of the record/replay process for a simulation tool;
[0082] FIG. 7 is a diagram of an extensible document parser of the present invention;
[0083] FIG. 8 is a diagram of a method for merging forms according to the present invention;
[0084] FIG. 9 is a diagram of input to a recorder according to the present invention;
[0085] FIG. 10 is a diagram of output from a recorder according to the present invention;
[0086] FIG. 11 is a diagram of a recorder of the present invention;
[0087] FIG. 12 is a flowchart of a method for operating a recorder according to the present invention;
[0088] FIG. 13 is a flowchart of a method for processing HTTP(S) transactions using a conventional recorder; and
[0089] FIG. 14 is a diagram of interfaces of a parser addition according to the present invention.
DETAILED DESCRIPTION
[0090] Extensible Document Parser
[0091] The present invention includes an extensible document parser 702 as shown in FIG. 7 , which can parse URLs by making use of the parser addition 1401 that standard document parsers overlook. Document parsers parse documents according to the syntax of the document type. The extensible document parser 702 has added functionality over the standard document parser since the extensible document parser 702 has a plug-in interface to include one or more parser additions 703 .
[0092] The parser addition 703 is a DLL (dynamic link library) having an interface that can be plugged into the extensible document parser 702 . The parser addition 703 is used by the extensible document parser 702 to parse additional frames 721 , embedded objects 722 , hyperlinks 723 and forms 724 from the document in addition to the standard frames 711 , embedded objects 712 , hyperlinks 713 , and forms 714 from the document.
[0093] The extensible document parser 702 passes the document to parse 701 and additional input parameters to the parser addition 703 . The parser addition 703 reports the parsing results back to the extensible document parser 702 by sending output parameters through the interface in the parser addition 703 that is plugged into the extensible document parser 702 .
[0094] The parser addition has another plug-in interface ( 1403 , FIG. 14 ) used by the recorder. By using the parser addition, the recorder can record a script that contains parser extensions. A parser extension is a replay instruction that specifies parser additions and configuration data for the parser additions. The recorder, by invoking this plug-in interface 1403 of the parser addition, determines the appropriate parser extensions to record into the script, so that a URL or form can be parsed during replay. Parser extensions can be in effect during the entire script execution or for individual page-level replay instructions only.
[0095] The parser extension specifies a parser addition and configuration data for this parser addition. In one embodiment, the configuration data for a parser addition consists of a left and aright boundary string. The parser addition first searches for the given left boundary string within the document. At each occurrence of the left boundary string, the parser addition searches for the next occurrence of the right boundary string. The text fragment found between the boundary strings is the resulting parsed URL.
[0096] In this embodiment, the configuration data for the parsing addition are the left and right boundary strings. Other types of parser additions (e.g. a parser addition that parses the document according to a regular expression) might have different kinds of input parameters (e.g. a regular expression).
[0097] Parser Addition
[0098] A parser addition 1401 shown in FIG. 14 is a software module that provides two interfaces 1402 , 1403 : one for use by the extensible document parser and one for use by the recorder, respectively. The preferred embodiment is a dynamic link library (DLL) with the interfaces being exported functions. However, any technology capable of implementing plug-ins is suitable, e.g., Microsoft COM or an object-oriented class framework.
[0099] The interface of the parser addition 1401 for the extensible document parser 1402 , referred to as “ParseDocument”, receives the document to parse and additional configuration parameters that completely depend on the parser addition. The parameters for a parser addition can be anything that is meaningful to parameterize the particular algorithm that the parser addition performs. The parser addition ( 1401 , FIG. 14 ; 703 , FIG. 7 ) outputs a list of embedded objects 721 , frames 722 , hyperlinks 723 , and forms 724 .
[0100] The interface of the parser addition 1401 for the recorder 1403 , referred to as “DetectParameters”, is used by the recorder. The input to the parser addition 1401 through this interface is a document and either a URL or a form. The output from the parser addition 1401 through this interface includes: a) parameters that can be passed to the interface ParseDocument along with the given document so that this interface can parse the given URL or form; or b) a notification that no suitable parameters can be detected.
[0101] The recorder according to the present invention chooses a parser addition from the library of available parser additions and parameters for the chosen parser addition so that the URL or form that would otherwise be hard-coded in the script can be parsed during script replay.
[0102] The recorder relies on the parser additions to detect suitable parameters. The recorder queries each one of the parser additions available in the library of parser additions 1112 using the interface DetectParameters 1403 of each parser addition.
[0103] For each parser addition in the library and for each document in the session history, the recorder queries the parser addition if there are suitable parameters for the parser addition so that the parser addition can parse the required URL or form from the given document. Some parser additions will succeed and provide a set of suitable parameters for some of these documents.
[0104] The result is a set of triplets, each one including a document, a parser addition, and parameters for the parser addition. Among this set, the recorder chooses one triplet which is the most suitable to be used. This choice may depend on several criteria related to both the document and the parser addition. For example, a document contained in the most recently accessed web page in the session history is preferred to a document contained in a web page farther back in the session history. Also, parser additions can be tagged with an estimation of the resource consumption (CPU, memory) the parser addition will need during script replay, and the recorder chooses the parser addition with the lowest estimated resource consumption.
[0105] It might still be possible that no parser addition is able to report success. In this case, the recorder of the present invention records a context-less replay instruction in the script, like a conventional recorder. However, the probability of the recorder of the present invention recording a context-less replay instruction decreases significantly as more parser additions with different parsing algorithms are available.
[0106] If the recorder can successfully choose parser additions and parameters for the parser additions, the recorder records a replay instruction to the script that specifies that the chosen parser addition with the chosen parameters is to be used during script replay and during the execution of the replay instruction that downloads the web page containing the document in which the parser addition can parse the required URL or form. Such a replay instruction is called “parser extension”.
[0107] The recorder then records a context-full replay instruction such as “FollowHyperlink” or “SubmitForm” instead of the context-less replay instruction such as “LoadPage” or “SendForm”. In other words, the recorder avoids context-less script instructions ( 1315 , 1316 , FIG. 13 ) and instead records context-full script instructions ( 1313 , 1314 , FIG. 13 ).
[0108] For example, an embodiment of a parser addition is a boundary searching parser addition. The interface “ParseDocument” of the boundary searching parser addition receives a left and a right boundary string in addition to the document to parse. The parser addition first searches for the given left boundary string within the document. At each occurrence of the left boundary string the parser addition searches for the next occurrence of the right boundary string. The text fragment found between the boundary strings is the resulting URL.
[0109] The interface “DetectParameters” of the boundary searching parser addition receives the document to parse and the URL that should be the parsing result.
[0110] The parser addition determines the parameters needed for the interface “ParseDocument” by first searching the URL within the document. If the URL cannot be found, the parser addition reports failure.
[0111] Otherwise, the parser addition takes the string on the left side of the occurrence of the URL within the document and estimates the number of characters that should be included in the left boundary string based on typical string characteristics. Then, it determines the number of characters on the right side of the occurrence to make sure the right boundary string does not occur within the URL to parse. The left and right boundary strings are recorded by the recorder as parser extensions in the script.
[0112] Fuzzy Form Detection
[0113] Fuzzy form detection according to the present invention is the process that a recorder employs when searching the session history for a faun that matches the form that is being submitted.
[0114] A recorder according to the present invention does not search for forms in the session history which are identical to the form being submitted. Instead, the recorder inspects all forms in all of the documents in the session history.
[0115] The recorder compares each form in the session history to the form being submitted. The result of this comparison is a set of data that describes the differences between the form being submitted and the form from the session history. This set of data includes:
[0116] Is the action URL identical or different?
[0117] How many form fields are unchanged?
[0118] How many form fields are changed?
[0119] How many form fields have been added?
[0120] How many form fields have been removed?
[0121] Based on the data from the comparison which is calculated for every form in the session history, the recorder chooses the form from the session history which is the most similar to the form being submitted. The recorder may assign levels of importance to individual differences. For example, a missing form field is a difference that is equal to five extra form fields.
[0122] If there are several forms in the session history with the same total level of difference to the form being submitted, the recorder applies additional criteria to choose among them. For example, the recorder prefers a form contained in the most recently accessed web page to a form further back in the session history.
[0123] Once the recorder has chosen the most suitable form from the session history, the recorder records a context-full replay instruction such as “SubmitForm” to the script along with merging instructions for the replay engine.
[0124] In the fuzzy form detection process, the recorder receives as input the form from the session history and the form being submitted by the recorded application and produces merging instructions for the replay engine. In the form merging process 804 as shown in FIG. 8 , the replay engine receives as input the form from the session history 801 and merging instructions 802 from the script and produces as output the form to be submitted 803 .
[0125] Furthermore, if the action URL of the form being submitted is different than the action URL of the form detected from the session history, the form merging instructions output to the script need to also specify a different action URL. The recorder finds a suitable parser addition and parameters for the parser addition so that a replay instruction can be recorded in the script to dynamically parse the different action URL during replay. The recorder then records form merging instructions containing a reference to the parsed action URL instead of the hard-coded action URL.
[0126] Form Merging
[0127] The present invention includes the process of form merging. Form merging instructions are contained in the script and used by the replay engine to determine how a form contained in a previously downloaded web page is merged with a form defined in the script to obtain the form that must be submitted to the web application.
[0128] The replay engine performs form merging 804 to obtain a form to be submitted 803 . The form to be submitted 803 is constructed by merging a document form 801 and a script form 802 according to form merging instructions, which are part of the script form 802 . The document form 801 is a form obtained by the extensible document parser and contained in a web page previously downloaded during the replay of the script. The script form 802 is a form defined in the script. While merging the document form 801 and the script form 802 , the replay engine follows form merging instructions recorded in the script to construct the form to be submitted.
[0129] The form merging instructions in the script can be a combination of, but are not limited to, the following:
[0130] Use the form field value specified in the form obtained by the document parser (i.e., the dynamic document value) for a form field of the same name in the form to be submitted.
[0131] Use the form field value specified in the form defined in the script (i.e., the static script value) for a form field of the same name in the form to be submitted.
[0132] Add a form field not present in the form obtained by the document parser. The form field name, value, and location among the existing form fields are specified in the script.
[0133] Suppress the form field specified from the form obtained by the document parser.
[0134] Although the form field is contained in the form in the web page, such a form field is not submitted.
[0135] The recorder decides whether to record the merging instruction “use document value” or “use script value” during the fuzzy form detection process. The recorder records the merging instruction “use document value” for all form fields where the value is the same as the initial value in the document, and records the instruction “use script value” only for form fields where the form field value differs from the initial value in the document (i.e., for those form fields that have been filled in by the user of the web application). So only user inputs get hard-coded in the script, but not hidden form fields or other unchanged values.
[0136] The example shown in FIG. 8 illustrates how the replay engine constructs a form to be submitted 803 from a form obtained from a previously downloaded web page by use of a document parser 801 and a form definition with merging instructions from the script 802 .
[0137] Form field “Product ID” 811 from the previously downloaded web page is compared to form field “Product ID” 812 from the form to be submitted. The form merging instruction 802 “use document value” specified using the fuzzy fowl detection process produces the result wherein the submitted form uses the dynamic value for “Product ID” 813 obtained from the document.
[0138] Form field “quantity” 821 from the previously downloaded web page is compared to form field “quantity” 822 from the form to be submitted. The form merging instruction 802 “use script value” specified using the fuzzy form detection process produces the result wherein the submitted form uses the scripted form field value “2” for form field “quantity” 823 from the script.
[0139] Form field “property” 831 from the previously downloaded web page is compared to form field “property” 832 from the form to be submitted. The form merging instruction 802 “remove form field” specified using the fuzzy form detection process produces the result wherein the submitted form does not contain the form field “property”.
[0140] The missing form field “color” from the previously downloaded web page is compared to form field “color” 842 from the form to be submitted. The form merging instruction 802 “add form field, use script value” specified using the fuzzy form detection process produces the result wherein the submitted form contains the form field “color” 843 and uses the form field value “blue” from the script.
[0141] Form field “SID” 851 from the previously downloaded web page is compared to form field “SID” 852 from the form to be submitted. The form merging instruction 802 “use document value” specified using the fuzzy form detection process produces the result wherein the submitted form uses the dynamic form field value for “SID” 853 from the document.
[0142] The missing form field “action” from the previously downloaded web page is compared to form field “action” 862 from the form to be submitted. The form merging instruction 802 “add form field, use script value” specified using the fuzzy form detection process produces the result wherein the submitted form contains the form field “action” 863 and uses the form field value “add to basket” from the script.
[0143] With a replay engine capable of form merging, it is possible to model web page transitions by a context-full replay instruction in situations where this would not be possible with a prior replay engine.
[0144] Examples for such situations are web application which embed incomplete forms within HTML documents, and modify these forms by means of client side code execution, e.g. JavaScript, prior to submitting such a form. Form modifications performed by client side code may be: adding form fields, removing form fields, renaming form fields or changing values of foam fields.
[0145] Reorder
[0146] The present invention includes a recorder that can choose suitable parser additions from a library of available parser additions that are needed for generating context-full replay instructions. The recorder of the present invention also performs fuzzy form detection.
[0147] The input of the recorder 1101 is a sequence of HTTP transactions as shown in FIG. 9 . Each HTTP transaction is either a simple HTTP transaction 901 or a compound HTTP transaction 902 .
[0148] A simple HTTP transaction includes meta data 910 (e.g., timestamps and IP addresses), a HTTP request header 911 , a HTTP request body 912 , a HTTP response header 913 , and a HTTP response body 914 . The HTTP response body 914 is the document that has been downloaded by the simple HTTP transaction.
[0149] A compound HTTP transaction includes a list of simple HTTP transactions that are related by HTTP redirections (HTTP status codes “301”, “302”) and/or authentications (HTTP status codes “401”, “407”).
[0150] The output of the recorder is a script 1001 consisting of a sequence of replay instructions 1010 , 1011 , 1012 , 1013 , 1014 , 1099 as shown in FIG. 10 . The replay instructions may contain form merging instructions 1010 , 1012 . The script can be recorded in any format that can be understood by the replay engine, e.g. plain text, XML, stored in a database, etc.
[0151] The recorder architecture is shown in FIG. 11 . The recorder 1101 includes a context analyzer 1104 to process the sequence of simple or compound HTTP(S) transactions 1102 , which it receives as input, one by one, as shown in FIG. 12 . After processing each HTTP(S) transaction 1102 , the recorder 1101 determines if there are more HTTP(S) transactions that need to be processed and continues until there are no more. The context analyzer recreates the web pages of the user session and logs these pages in the session history 1105 . The context analyzer uses the extensible document parser to parse documents contained in the HTTP transactions 1102 so that it is possible to recreate web pages and identify page transitions. When the context analyzer identifies a page transition, it records a replay instruction to the script 1108 using a script generator 1106 . The recorder has a library of document parser additions 1112 which are available to the extensible document parser.
[0152] The present invention includes the library of parser additions 1112 and an extensible document parser 1111 to enhance the operation of the context analyzer 1104 to ensure that the recorder records context-full replay instructions to the script 1108 . | The present invention relates to a method and apparatus for providing automatic context management for simulating virtual users for testing and monitoring web applications, including those web applications that execute code on the client side, without requiring the actual execution of client side web application code or the execution of the client within the testing, monitoring, or simulation tool. Simulation tools with automatic context management according to the present invention can record and replay context-full scripts that do not require manual customization and are capable of handling state information even for web applications that execute code on the client side. These scripts are able to realistically mimic complex web application transactions on the network HTTP layer. | 7 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from U.S. Provisional Patent Application No. 61/077,959 filed on Jul. 3, 2008, entitled “Vented Container and Method of Manufacturing,” which application is assigned to the same assignee as this application and whose disclosure is incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a container, or a cap for a container, which includes a venting mechanism that precludes the leakage of liquid or other flowable contents, e.g. particulates, from the container.
BACKGROUND OF THE INVENTION
[0003] The problem of container deformation in response to pressure differences existing between the inside of a closed container and the ambient pressure is well known in the packaging industry. Such container deformation may be non-recoverable for certain container materials, such as some rigid or semi-rigid structures made of plastics or metals. Thin-walled, flexible or partially flexible containers can be particularly sensitive to the problem.
[0004] While not wishing to be bound to any particular theory, there are a number of possible factors which may lead to the existence of the pressure differences between the interior and the exterior of the container mentioned above. The contents of the container may, for example, be chemically unstable or may be sensitive to certain contaminants such as might occur in a reaction between the gases which may exist in the head space of the container and the contents of the container, or alternatively, in certain specific circumstances, where the contents of the container may react with the container material itself. Any chemical reactions involving the contents may lead to either production of gases, and hence to overpressure in the container, or to the absorption of any head space gases thereby causing under pressure in the container. In addition, the solid contents may absorb moisture, such as created by condensation due to temperature differentials and become soggy or saturated.
[0005] Pressure differences between the pressure inside the container and the ambient atmospheric pressure may also occur when the temperature during the filling and sealing of the container is significantly different from external temperature during shipment, transportation and storage. Another possibility of a pressure difference may be caused by a different ambient pressure at the filling of the container from another ambient pressure at a different geographical location.
[0006] The prior art has proposed several solutions using valve systems which avoid pressure differences between the interior and the exterior of the container. Proposed solutions also relate to various venting caps which allow pressure generated inside the container to be released by escape of gas. U.S. Pat. No. 4,136,796 and EP 0 752 376 disclose self venting closures having a gas-permeable membrane covering an orifice to the exterior atmosphere. These membranes are made of a material which is impermeable to liquids, but permeable to gases. Therefore, these containers may have apertures to release gas to the exterior without losing their leak-tightness. U.S. Pat. No. 5,988,426 and EP 337677 disclose a vented lid that relies on a hydrophobic material to allow passage of air through the vent hole and prevent the passage of liquids through the vent hole. Another example U.S. Pat. No. 6,886,579 relies on a ball bearing mechanism to seal the vent and prevent spillage of liquid contents. Additionally, OB I 146 972 discloses a venting cap to be fitted onto the mouth of a container. It allows the passage of gases while preventing passage of liquids through the venting membrane. This is achieved by choosing the size of the pores in the membrane.
[0007] The use of membranes in these applications can add a considerable expense to the venting system. Tests have shown that when containers are heated to sufficient temperature to cause internal pressures to develop, leakage through the membrane occurs. In the case of mechanical closures, these devices can also add complexity and cost to the vent system and can suffer from malfunction and breakage of the mechanical components. Therefore the need exists for a container for a flowable product such as liquid or particulate, or a cap for such a container, which allows venting of the container while preventing the leakage of the flowable contents from the container even under conditions where internal pressures exist.
BRIEF SUMMARY OF THE INVENTION
[0008] The embodiments of the present invention described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of the present invention.
[0009] The present invention relates to a container, or a cap that may be used a container, which includes a venting means and at the same time prevents leakage of liquid or other flowable contents from within the container.
[0010] In one embodiment of the presently described invention, an imperforate cap structure is placed atop a vent hole that extends from the interior of a container to the exterior of the container, that is completely through the container wall. This cap is sealably affixed to the container wall. On top of the vented hole a dome like structure is positioned and is preferably constructed of a flexible, impervious material. The dome structure has an internal area and a radially extending venting area and a further radially extending external flange area. The flange area is fastened to the container in such a way so as to maintain coverage of the vent by the internal area of the dome. The venting area of the dome is located so as to not overlie the vent hole. The venting area of the dome has perforations sufficient to allow air flow through the dome. On top of the dome is positioned a porous expandable absorbent, which has an upper surface and a lower surface, so as to fill the area within the cap, but not to exert pressure upon the dome. The dome is positioned adjacent the lower surface. On top of the domed structure and the absorbent material is an imperforate rigid cap that is sealably attached to the surface of the container. Thus, in a situation of normal usage or storage where the contents of the container were of higher pressure than the external atmosphere, gasses from within the container would flow through the vent hole, through the venting area of the dome, around and through the absorbent material and finally through the imperforate area of the cap. Splashing or sloshing of the liquid or other flowable contents during use or shipment or handling is anticipated. Minor amounts of liquid splashing into the vent hole would be contained in the domed structure and would then drain back into the container. In situations of abnormal usage or storage wherein the liquid or other flowable contents of the container are brought in direct and prolonged contact with the vent hole, the contents would pass through the venting area of the dome and be absorbed into the expandable absorbent. Once moistened by the liquid, the absorbent would expand against the imperforate cap and collapse the dome structure from a first open position to a second closed position, thereby pressing the interior area of the dome into direct contact with the vent hole and sealing the vent hole to further leakage.
[0011] In a further embodiment of the presently described invention, an additional domed structure is placed within the cap structure, on top of the imperforations in the cap. That is, the invention may include first and second domed structures that move between a first open position and a second closed position. Upon expansion of the absorbent material, both the domed structures are collapsed and placed in direct contact with the vent hole and imperforate area in the cap. As a result, the area between the container and the cap are sealed and isolated and leakage of the liquid material from the construction is prevented.
[0012] In yet another embodiment of the presently described invention, the venting device is preassembled and is sealably attached to the container such that the venting device overlies the vent hole in the container. In this case a dome like structure of flexible impervious material that has an internal area and a radially external venting area and a further radially extending external flange area is prepared. On top of the dome is placed a porous expandable absorbent so as to fill the area within the cap, but not to exert pressure upon the dome. On top of the domed structure and the absorbent material is an imperforate rigid cap that is sealably attached to the flange area of the dome. The venting device can then be sealably attached to the container.
[0013] Other features and advantages of the present invention will become apparent to those skilled in the art from the following detailed description. It is to be understood, however, that the detailed description of the various embodiments and specific examples, while indicating preferred and other embodiments of the present invention, are given by way of illustration and not limitation. Many changes and modifications within the scope of the present invention may be made without departing from the spirit thereof, and the invention includes all such modifications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] These, as well as other objects and advantages of this invention, will be more completely understood and appreciated by referring to the following more detailed description of the exemplary embodiments of the invention in conjunction with the accompanying drawings, of which:
[0015] FIG. 1 is a perspective view depicting one version of a dome structure;
[0016] FIG. 2 is a perspective view of one embodiment of the presently described invention illustrating a dome structure and absorbent material configuration;
[0017] FIG. 3 is a perspective view of yet a further embodiment of the presently described invention providing a plural domed structure;
[0018] FIG. 4 is a perspective view of one embodiment of the presently described invention where the absorbent layer has expanded, crushing the dome structure and sealed the container from further leakage;
[0019] FIG. 5 is a perspective view of yet a further embodiment where the vent device is constructed as a screw cap for attachment to a container;
[0020] FIG. 6 is a perspective view of an embodiment where the vent device is a stand alone device that can subsequently be attached to a container;
[0021] FIG. 7 is a perspective view of the stand alone vent device attached to a container;
[0022] FIG. 8 provides a block diagram of an exemplary method for making a vented container; and
[0023] FIG. 9 is a flow chart of another exemplary method of making a vented container.
DETAILED DESCRIPTION OF THE INVENTION
[0024] The present invention is now illustrated in greater detail by way of the following detailed description which represents the best presently known mode of carrying out the invention. However, it should be understood that this description is not to be used to limit the present invention, but rather, is provided for the purpose of illustrating the general features of the invention.
[0025] Referring to FIG. 1 , an imperforate dome structure 5 is shown to have an internal area 10 and a radially extending external perforated venting area 20 and a further radially extending external flange area 30 .
[0026] FIG. 2 provides a vented container 100 that includes a vent 120 . On top of this vent 120 is affixed a domed structure 5 . A flange area 30 is fastened to the container 100 , such as by adhesive, sonic welding, in mold or the like, in such a way as to maintain coverage of the vent 120 by the internal area 10 of the dome. The venting area of the dome 20 is located such as to not cover or block the vent hole 120 . On top of the dome 5 is placed a porous expandable absorbent 130 . The absorbent 130 has an upper and lower surface and the dome 5 is positioned against the lower surface. Placed on top of the absorbent material 130 and attached to the container 100 is a rigid cap 140 with at least one perforation or opening 150 .
[0027] Reference is now directed to FIG. 3 , where an additional or second domed structure 200 is used in the container construction. The additional dome 200 is positioned immediately beneath the opening 150 , and adjacent the upper surface of the absorbent 130 so as to provide a further closure mechanism when the absorbent material expands to prevent either leakage of the contents or seepage from the environment. As seen from FIG. 3 , the second domed structure 200 is placed in an inverted position when compared to the first domed structure 5 . Each of the first and second domed structures, 5 and 200, respectively, can move between a first open position and second closed position.
[0028] The domed structure 5 is positioned to ensure that surface or flange 20 of the domed structure 5 does not come in cover or obscure the vent 120 until such time as the absorbent material 130 swells due to liquid contact and causes the dome 5 to collapse over the vent 120 thereby sealing the vent 120 from further leakage.
[0029] FIG. 4 , illustrates the container construction provided in FIG. 2 , showing the container closure after subjecting it to abnormal use conditions so that the expandable absorbent 130 has absorbed the leaking liquid and has expanded in order to collapse the domed structure 5 to a second closed position from a first open position shown in FIGS. 2 or 3 . The pressure exerted by the absorbent material causes the dome 5 to come in direct contact with vent hole 120 so as to prevent further leakage of the liquid contents of the container. The second position of the domed structure is substantially flat and forms a generally planar configuration with the top of the container on which it is seated.
[0030] Referring to FIG. 5 , the vent device is constructed as a screw cap 170 for the container showing a series of threads to fasten the cap 170 to the container. While FIG. 5 provides only a single domed structure 5 , it should be understood that a plural domed structure as provide in FIG. 3 could be provided.
[0031] Reference is now directed to FIG. 6 and 7 , the vented device is constructed as a preassembled unit 180 which can then be sealably attached to a container 100 such that it overlies the vent hole 120 in the container.
[0032] The absorbent material 130 provided in the exemplary embodiments of the presently described invention, can be of any material that expands when exposed to the liquid contents of the container. One example of such a material is compressed cellulose available from either (a) “The Color Wheel Company”, Philomath, Oreg. under the Trade Name of “Miracle Sponges” or (b) “The Absorene Manufacturing Company Inc”, St. Louis, Mo. under the Trade Name of Cellulose Discs. Another example of a suitable material for use with the present invention is a non-woven construction that is impregnated with super absorbent polymer available from Scapa North America of Windsor, Conn. under the product designations including WSD-244, L-550 and WSD-252. These materials were used in sufficient layers such that upon expansion of the materials, sufficient pressure was exerted on the domed structure so as to create a seal.
[0033] In order to compare materials provided in the prior art with those of the current invention, a test protocol was embraced. To simulate hair care products, ten ounce plastic bottles were filled to 90% of their volume with 3% hydrogen peroxide. In the case of non-woven materials and micro porous films, the test materials were affixed to the inside surface of a cap. This cap had a 16″ hole placed in its top surface. The cap was then attached to the bottle. In the case of the current invention, the constructions of FIG. 2 and FIG. 3 were tested. The bottles were then inverted to expose the test materials to the liquid contents of the bottle. The bottles, still in the inverted position, were then placed in an oven at 50° C. for twenty hours and observed for leakage.
[0034] The porous non-wovens tested were (a) product codes 18007, 12085, 17509 and 26402 from Alstrom of Windsor Locks, Conn.; and (b) product codes DP3930-100H and DP5001-140P from Delstar of Middletown, Del. The micro porous films tested were (a) product codes AC38 from Clopay of Mason, Ohio and (b) product codes PM-1020 and PM-3V for Mupor PTFE from Porex of Fairport, Ga. All of the non-wovens and films listed above did not pass the twenty hour test. Only the constructions of this invention passed the test by not allowing any of the liquid contents of the bottle to exit the container.
[0035] An exemplary method of making a vented container is illustrated in FIG. 8 . A method is described wherein at step 300 , a container 100 is provided and at step 400 a venting device 180 is sealably attached to the container. The venting device including: (a) an imperforate domed structure that has an internal area and a radially extending venting area and a further radially extending external flange area beyond the vent area; (b) an absorbent material overlies the domed structure to absorb any liquid contents of the container; and (c) an imperforate rigid cap is sealably attached to the flange area of the domed structure; over the opening and the venting device is sealably attached to the surface of a container such that it overlies a vent hole in the container.
[0036] Another exemplary method for making a vented container is illustrated in FIG. 9 . A method is described wherein at step 500 a perforated domed structure 5 is created and at step 510 a container 100 is provided. At step 520 the domed structure is sealably attached to the container so that the domed structure overlies the opening 120 and is not in direct contact with the opening, that is the domed structure does not block the opening. At step 530 an absorbent material 130 is placed so as to overly the domed structure and at step 540 an imperforate rigid cap 140 is placed so as to overly the absorbent material. At step 550 the cap is sealably attached to the surface of the container.
[0037] It will thus be seen according to the present invention a highly advantageous vented container has been provided. While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it will be apparent to those of ordinary skill in the art that the invention is not to be limited to the disclosed embodiment, and that many modifications and equivalent arrangements may be made thereof within the scope of the invention, which scope is to be accorded the broadest interpretation of the appended claims so as to encompass all equivalent structures and products.
[0038] The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of their invention as it pertains to any apparatus, system, method or article not materially departing from but outside the literal scope of the invention as set out in the following claims. | A venting device that may be used directly with a container or via a vent cap for a container, includes a venting mechanism having one or more collapsible dome structures and an absorbent material to prevent leakage of liquid or flowable contents from within the container. The construction relies on a combination of venting domed structures and expandable absorbent material to seal one or more openings in a container and or cap. | 8 |
BACKGROUND OF THE INVENTION
The present invention relates to mechanical transmissions and more particularly to a multi-function wheel transmission for wheelchairs and the like.
Conventional wheelchairs provide necessary mobility for the disabled. Manually driven chairs have an advantage in that they provide the opportunity for some physical exercise. Nevertheless, manual chairs are limiting to the user because pathways must be relatively flat for easy and safe locomotion. Sloping surfaces are more difficult to roll a chair up than a flat surface and a downward slope can be dangerous if the user loses control of the wheels. Substantial strength and dexterity are required for locomotion on sloping surfaces. A braking mechanism must be included for safety.
Electric wheelchairs give mobility to the disabled for a wide variety of terrain. But electric chairs can be expensive and bulky and deprive the user of physical exercise. Manually driven wheelchairs provide a lesser degree of mobility but are lighter, less expensive and can provide a good opportunity for controlled exercise.
It is therefore an object of the present invention to provide a new multi-speed transmission for use in a mobility enhancing vehicle, such as a wheelchair.
It is another object of the present invention to provide a new braking mechanism in a mobility vehicle.
It is yet another object of the present invention to provide a new multi-function transmission for use in a mobility enhancing vehicle which has a braking mechanism for safety.
SUMMARY OF THE INVENTION
The present invention relates to mechanical transmissions and more particularly to a multi-function wheel transmission for wheelchairs and other mobility enhancing vehicles. In an embodiment of the present invention, a selectable “low gear” is provided for going up a hill. Use of this embodiment in a wheelchair lessens user anxiety by inherently providing a safety mechanism that prevents runaway on a ramped or sloped surface; this innovation provides increased mechanical advantage while also having inherent safety braking. The result is enhanced confidence and mobility both for an average user and for a hard driving athlete in a manual wheelchair.
A preferred embodiment of the invention is built into each wheel and has two modes. The user selects the mode by using a braking lever. When the brake is off the wheelchair operates like a conventional manual chair. The user strokes the drive rim to drive the chair. This is the normal mode.
When the brake is set, then the wheelchair acts as if the brake is on as in the conventional manner. But if the drive rim is stroked then the wheelchair is propelled via the torque-amplifying hub transmission of the invention. The result is that the wheelchair can traverse a steep incline or decline and as soon as the user stops driving the rim, the wheelchair safely comes to a stop. Now threatening hills and steep ramps can be safely traversed at any rate, slow or fast, even with a rest stop in the middle. With the hub transmission engaged, there can be no runaway. This is the speed converter mode.
In use, just like using low gear on a bike, compared to a conventional wheelchair trying to go up a steep incline, the hub makes it much easier on the muscles—and feels it—because of it is a torque amplifier. The chair is used in the convention manner when rolling on level ground. But when easier propulsion or self-braking is important, the user puts the brakes on and then uses the drive rim through the hub for propulsion.
The mechanical advantage in the hub can be so effective as to make it possible for a user to propel up an incline that heretofore was considered insurmountable. Or this mechanical advantage may benefit an aged or enfeebled user even on a level surface. In any event, the hub invention can extend the range of mobility of the conventional manual wheelchair and its user. The present invention results in increased mobility in an easy to use and cost-effective wheel design for any wheelchair, new or retrofit.
Since athletic events for the wheelchair-bound are becoming more popular, there is a variation on the above theme that is part of the invention. Rather than a speed reducer hub, we implement a speed increaser hub for a racing wheelchair, where the user can select a high-speed overdrive mode to increase the top-end speed achievable by the racer. In this case the speed increaser is used for much like a high gear in an automobile. The shift mechanism for the wheels can be tied together to be activated simultaneously and on-the-fly. There is no auto-braking feature in this embodiment.
In a preferred embodiment of the invention, each wheel has a single drive rim that performs two functions. A brake assembly is provided to manually shift between two modes: a 1:1 conventional drive mode and a n:1 non-backdrivable self-braking mode. In the latter mode, rotary motion applied to the rim is translated via a hub assembly to drive the wheel via a non-backdrivable torque amplifying speed reducer. In this aspect of the invention, the wheel brake is automatically applied to the wheel to stop unwanted motion, unless the drive rim is rotated. In another aspect of the invention, when the brake is disengaged, per wheel, rotation of the drive rim drives the wheel in a conventional manner.
In a preferred embodiment of the present invention rotary motion applied to the drive rim is translated via a conjugate pair of devices rotatable about a common axis, and a ball or roller type translating arrangement, interposed between the conjugate pair about the common axis, including a slotted retainer device, forming a torque amplifying non-backdrivable speed reducer, to drive the wheel. When the drive rim is not being rotated and the brake is engaged, then the wheel is automatically prevented from rolling to stop unwanted motion unless the drive rim is intentionally driven. When the brake is disengaged, rotation of the drive rim drives the wheel in a conventional manner.
It will now be appreciated that a multi-motion transmission is disclosed, having an input, reaction system, housing, and output. In an embodiment of the invention, a first of these items connects to a second one to form a first mode of operation, and the first of the items decouples from the second one and couples to a third item to form a second mode of operation. Speed conversion apparatus is provided and the input is rotatably coupled to the output via the speed conversion apparatus in one mode of operation, wherein the input has a first rate of motion and the output has a second rate of motion.
Clutching provides for selectively switching between the first mode and second mode, and selectively engages one of the said items to other ones of said items, for provision of the first rate of motion in one mode and a second rate of motion in the other said mode. In a preferred embodiment, this clutching action enables a braking function in one mode, where the hub transmission includes a non-backdrivable speed reducer. In another embodiment, the speed conversion apparatus is a backdrivable speed increaser.
Preferably the transmission of the invention includes a conjugate pair of devices nested concentrically about a common axis, where a first of the pair of the devices is an inner cam gear and the second is an outer cam gear. The cam gears may include rotary wavy tracks. A slotted part is nested between the two can gears and has a plurality of slots for receipt of interacting elements (balls or rollers). Where the transmission has a housing, such as a wheelchair frame, the input and output are selectively rotatable relative to the housing, wherein a shifting part engages one of the devices for switching between a first mode and a second mode of operation, such as for switching between 1:1 and n:1 operation.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages of the present invention will be more fully understood by reference to the following detailed description in conjunction with the attached drawing in which like reference numerals refer to like elements and in which:
FIGS. 1A and 1B show prior art wheelchair and wheel design, respectively.
FIG. 2 is a perspective view of a preferred wheelchair embodiment of the present invention.
FIG. 3 is a side cross-section of a wheel assembly embodiment of the invention.
FIG. 4 is a plan view of a preferred nested speed reducer in practice of the invention of FIG. 3 .
FIG. 5 is a perspective view of the inner cam gear assembly of an embodiment of the invention.
FIG. 6 is a perspective view of the slotted member of an embodiment of the invention.
FIG. 7 is a plan view of the outer cam gear and wheel assembly of an embodiment of the invention.
FIG. 8 is a perspective view of a shifting lever of an embodiment of the invention.
FIG. 9 is a perspective view of a mode switching shuttle assembly of an embodiment of the invention.
FIG. 10 is a plan view of a rim assembly of an embodiment of the invention.
FIG. 11 is a plan view of a nested speed increaser in practice of an embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1A and 1B show a conventional wheelchair 10 and a conventional wheel assembly 11 . This assembly has wheel 12 on hub 13 , spinning on shaft 14 mounted to the chair frame 15 under seat 16 . Attached to wheel 12 is a drive rim 17 . Hand brake 18 prevents the chair from rolling unintentionally. Hand rotation of rim 17 rotates wheel 12 to manually propel the wheelchair when the brake is not set.
When it is desired to manually propel this wheelchair up or down a long or steep incline, the task becomes more difficult. This is because the chair wants to roll down the incline of its own accord and the user is put at risk if he releases his hand from the drive rim to rest or even to put on the hand brake. Going up or down a slope must be able to be achieved safely at a controlled rate.
The present invention overcomes these difficulties by being switchable between two modes, one is the conventional free-wheeling mode and the other is a new self-braking mode. In the free-wheeling mode, the rim and wheel operates conventionally as if the brake is off. In the self-braking mode, the wheel operates as if it has a brake set on it, but the rim is still rotatable to achieve wheelchair motion on demand.
As shown in FIGS. 2-11, wheel assembly embodiment 100 of the present invention has the conventional rubber wheel 12 on a special hub 113 , and a mode switching mechanism 118 that includes a braking assembly 119 . Also provided is a drive rim 117 that drives a hub transmission assembly 120 . The hub transmission assembly 120 includes a speed converter 121 , taking the form of a speed reducer 121 ′ (FIG. 4) or speed increaser 121 ″ (FIG. 11) according to desired effect as described below.
In a preferred embodiment of the invention, the speed converter 121 is a n:1 speed reducer 121 ′ and is engaged when brake assembly 119 is set to the self-holding mode. When the brake is thus engaged, rim 117 is used to propel the wheelchair with the torque amplifying benefit of n:1 speed reduction. In a preferred embodiment, the ratio is 4:1 and has a self-holding (i.e., non-backdrivable) output on which the wheel 12 is mounted. When the brake is set, wheel 12 is driven via this self-holding output when rim 117 is rotated. But when the brake is set and the rim is still, the wheelchair stays still even on a sloping surface. This is the self-braking mode.
When the brake assembly 119 is released, speed converter 121 is locked up assembly and can be freely rotated via rim 117 in the conventional 1:1 manner to drive wheel 12 . This is the conventional free-wheeling mode.
It will thus be appreciated that this arrangement solves the conventional wheelchair mobility problems by providing a 1:1 drive for usual wheelchair use via conventional use of the drive rim 117 with the “brake” off. But with the “brake” engaged, the self-holding hub transmission 120 is driven by rotation of rim 117 to provides n:1 extra mechanical advantage that enables traverse of sloped surfaces. The extra mechanical advantage and the safety of self-holding provides a level of mobility and safety to the manually driven wheelchair of the invention. When the rim is still, the wheel is still and held in place as if a conventional brake were holding it thus.
A preferred practice of hub transmission 120 uses a cam gear and roller/ball type speed converter. As shown in FIGS. 4, a preferred speed reducer 121 ′ of the present invention includes outer cam gear 212 , inner cam gear 214 , slotted intermediate member 216 , the latter having slots 218 for receipt of rolling elements (balls or rollers) 220 . Outer gear 212 has projections which define teeth or tooth flanks 222 . Inner gear 214 has projections which define tooth flanks 224 . Slots 218 have defined flanks 226 .
As shown in FIG. 5, the cylindrical inner cam gear part 214 ′ includes cam gear 214 , and tooth projections or flanks 224 . As shown in FIG. 6, the intermediate cylindrical slotted assembly 216 ′ includes the slotted part 216 , slots 218 and pin guides or receivers 230 . As shown in FIG. 7, the cylindrical outer cam gear part 212 ′ includes hub 113 which defines cam gear 212 with tooth projections or flanks 222 . The rim assembly 117 ′ is affixed to inner cam gear 214 via bolts 221 in tapped holes 223 of the inner cam gear.
Brake assembly 119 is mounted on the chair frame 15 and engages a braking plate 217 that is coupled to speed converting hub transmission 120 . The hub 120 is rotatably mounted on axle 228 , and axle 228 is fixed to the wheelchair frame 15 . When the brake assembly is set to the free-wheeling mode, rotation of rim 117 drives the entire hub assembly as one internally locked part to drive the wheel into rotation without any additional speed ratio other than from use of the conventional rim, hence referred to as 1:1. The brake assembly is described in detail below.
In a preferred embodiment, when the brake assembly 119 is engaged then the intermediate part 216 is non-rotatably coupled via brake assembly 119 and the brake plate 217 to the chair frame 15 . Now rotation of rim 117 , mounted to inner cam gear 214 , rotates the inner cam gear 214 as a drive input. This rotation drives rollers 220 against the flanks of outer cam gear 212 while reacting on the flanks 226 of the slots 218 of the fixed intermediate part 216 . This action drives outer cam gear 212 —and thus the wheel 12 —into rotation. The speed reduction ratio of speed converter 121 is determined by comparing the greater number of teeth of the driven gear to the lesser number of teeth of the drive gear. In the example of FIG. 4, the outer cam gear defines eight teeth and the inner defines two teeth. The slotted member has 6 slots, with a rolling element in each slot. The speed reduction ratio is 8:2 or 4:1.
A speed reducer is a torque amplifier. By providing torque amplification to the wheel chair it is possible to manually drive the chair up a steep incline without too much effort. The non-backdrivability feature of the invention assures that there is no loss of control on a sloping surface.
In practice of an embodiment of the invention, rim 117 and inner cam gear 214 to which it is affixed are able to be rotated clockwise or counter clockwise when the brake is set, as would seem conventional, and then the output (i.e., wheel 12 mounted on outer cam gear 212 ) rotates accordingly at an n:1 torque-amplified reduced speed. If the speed reducer output is non-backdrivable, then the output of the speed reducer cannot be rotated as if it were an input to backdrive into the hub transmission. Thus the non-backdrivable speed converter assembly 121 will not let the wheels roll randomly, thus acting as a brake if it is engaged in the self-holding mode. With the brake set, if a user is propelling himself up or down a slope, then when he stops spinning the rim and even lets go of rim 117 , the chair will come to rest as the rim spins to rest and will stay at rest until the user again rotates the rim. Pushing on the chair will not move the chair. The chair will not roll randomly. This is the self-braking mode.
This selectable self-braking mode is an important safety feature for riding of sloping terrain and permits a handicapped rider to increase his range of exploration to beyond conventional flat places. In using the speed reducer as a brake, the user can spin the rim down slowly for gradual stopping or abruptly for sudden stopping, as desired. When on flat terrain the user can select the free-wheeling mode.
The user can release the brake and switch into 1:1 mode, freeing up the speed reducer 121 ′ so that it can freely rotate, and then he can use the chair in the conventional manner, even allowing it to roll down a slope at will. This 1:1 mode is the standard wheeling mode, where the rim and wheel will rotate as in a conventional wheelchair. When the speed reducer 121 ′ is freed up in this manner, it also simultaneously becomes intentionally locked up, so that drive rotation of rim 117 will be transmitted faithfully to wheel 12 .
In either mode, anytime the user wants to move he can rotate rim 117 . An additional conventional brake can be added for special cases.
It has been discovered that the non-backdrivable character describes a static condition of this nested speed reducer of FIG. 4, such that when the input cam gear 214 is at rest, the output 212 is not backdrivable into the device. The output cannot be used as an input to drive the input cam gear 214 into rotation. This non-backdriveability appears to be an artifact of the “stiction” between the at-rest interacting elements and the contacted flanks of the slots and cam gears, where there is a high resistance to initiation of rolling of the interacting elements upon input rotation of the multi-toothed outer gear 212 even if the wheelchair were pushed or if it were on a steep slope. This self-holding is a static condition. The invention permits a limited degree of backdriving (coasting) when the wheels are rolling, but essentially the wheels will spin down as the rim spins down.
This static high resistance to rolling is a function of pressure angle design of the cam gear tooth flank profiles. As with gears, the pressure angle is defined as the angle between the tangent surface at the contact point and a radius drawn between the contact point and the axis of rotation. Using this angle, the contact force may be decomposed into a tangential force (which contributes to torque transmission and scales with the cosine of the pressure angle) and a radial force (which does not contribute to torque transmission and scales with the sine of the pressure angle). The concept of pressure angles for gears is well known and will be appreciated by a person skilled in the art of speed converters to apply to the teeth of the disclosed cam gears.
The cam gear teeth of converter 121 as a speed reducer are configured with a pressure angle so shallow that backdriving from at rest cannot occur from the output. The pressure angle (PA) is defined, as with gears, as the angle between the tangent surface (t) at the contact point and a radius (r) drawn between the contact point and the axis of rotation. The following definitions are made, where the input rotation is applied to the low-tooth count cam:
Term or symbol
Meaning
μ
Coefficient of (static) friction between ball and low
cam
N
Number of teeth on low cam
ΔR
Rolling element stroke in slot
R avg
Average (mid-stroke) distance of rolling element
center from axis of rotation of drive
α
Half-lobe angle of low cam, given by α = π/N radians
PA
The pressure angle is 90°-α.
ν
Crossing angle over rolling element of track on low
cam, given by ν = tan −1 (ΔR/R avg α)
In light of these definitions, the non-backdriveability condition in the conventional sense for speed conversion mechanisms of the above kind can be expressed in the following relationship (and as the definition of “shallow”):
μ>tanυ.
When this condition holds, the output 212 cannot backdrive into the low tooth-count cam gear input 214 ; otherwise, the drive is backdrivable (whether it is a speed reducer or speed increaser).
Therefore speed converter 121 as a non-backdrivable speed reducer 121 ′ along with mode switching assembly 118 defines a braking mechanism 119 of the invention. The cam gears 212 and 214 are configured with pressure angles that are so shallow that backdriving from at rest cannot occur from the output 212 toward the input 214 . Thus the wheelchair at rest remains at rest when the speed reducer 121 ′ is engaged via the brake assembly 119 .
Referring to FIGS. 2-10, the brake assembly 119 includes a mode shifting device 232 having a handle 234 and a barrel 236 mounted on shaft 228 . Barrel 236 defines a cam slot 238 and a pin 240 mounted in shaft 228 rides in the cam slot 238 . Bearing 242 is slideably mounted on shaft 228 . Plate 244 is fixed to the chair frame 15 . Bearing 242 slides through plate 244 and up against plate 217 of shuttle assembly 248 . Plate 217 is affixed to the ends of pins 250 which are slideably mounted in pin receivers 230 of slotted part 216 . The pins 250 also mount to the base of a braking plate 252 of shuttle assembly 248 .
The mode shifting device 232 is shifted between the two mode positions, A and B. When handle 234 is rotated, say clockwise, the mode shifting device 232 is shifted into the “normal” position, with pin 240 located at position A of cam track 238 . The resulting travel of barrel 236 along axle 228 forces bearing 242 inward against plate 217 of shuttle assembly 248 , which in turn drives shuttle assembly 248 until its plate 252 drives up against a braking surface 254 on the hub 256 of rim assembly 117 ′. Rim assembly 117 ′ remains bolted to the inner cam gear 214 , but this action also locks the intermediate slotted part 216 to the inner cam gear 214 via the rim assembly 117 ′ connection. This action locks up the speed converter 121 while also freeing the entire speed converter to be rotatable on axle 228 . Plate 217 of shuttle assembly 248 is pulled away from plate 244 and is rotatable along with speed converter 121 . The speed converter is thus locked up but is rotatable on axle 228 . The speed converter rotates as a solid assembly carrying rotation of the rim 117 to the wheel 12 without speed conversion, as in a convention manner. This is the normal or free-wheeling mode of operation.
It will now be understood that when the shuttle is moved to its second position using the mode shifting mechanism 232 , the shuttle disengages any fixed connection between the speed reducer 121 ′ and frame 15 and locks up the speed reducer internally by locking the slotted part 216 and outer cam gear 212 together to prevent relative movement between the parts 212 , 214 and 216 . This also frees up the speed converter assembly 121 to rotate on axle 228 . The speed converter assembly being thus free to rotate and yet also internally locked up, delivers the drive motion on the drive rim to the wheel without any additional speed reduction. The result is that rim 117 operates as if it were conventional, driving the wheel in a conventional manner as though the brake were disengaged.
When handle 234 is rotated counter-clockwise, the mode shifting device 232 shifts to the “self-braking” position, with pin 240 now located at position B of cam track 238 . Spring 260 drives plate 217 against fixed plate 244 . Acting like a disk brake, now plate 217 and plate 244 are non-rotatably held together and fixed to the frame. Braking plate 252 of the shuttle assembly 248 is pulled away from the braking surface 254 of rim assembly 117 ′. The rim assembly 117 ′ remains affixed to inner cam gear 214 .
With plate 217 and plate 244 non-rotatably held together and locked to the frame, the shuttle assembly 248 and intermediate part 216 are now non-rotatable. With braking plate 252 now pulled away from the braking surface 254 of rim assembly 117 ′, speed converter 121 is ready to operate. Rotating rim 117 now rotates the inner cam gear 214 as a drive input. This rotation drives rollers 220 against the flanks of outer cam gear 212 while reacting on the flanks 226 of the slots 218 of the fixed intermediate part 216 . This action drives outer cam gear 212 , and thus the wheel 12 , into rotation according to the speed ratio of speed converter 121 .
It will now be appreciated that the shuttle assembly 248 is shifted between two positions by the mode shifting mechanism 232 . In one position the shuttle engages the chair frame 15 to lock down the slotted part 216 to the frame. Now rotation of drive rim 117 rotates inner cam gear 214 , which drives outer cam gear 212 into rotation according to the speed ratio of speed converter. The chair is propelled accordingly. With speed converter 121 designed as a non-backdrivable speed reducing mechanism, when the rim is at rest then the chair is at rest, and the speed converter performs the braking function automatically. Without further shifting of the mode shifting mechanism, any rotation of the rim propels the chair as long as the rim keeps spinning. With the rim at rest the chair stays at rest.
If speed converter 121 is a non-backdrivable speed reducer then it acts as a brake when engaged. As soon as the shuttle is shifted out of conventional mode and into the self-braking mode, the speed reducer 121 ′ is again engaged and acts as the brake to hold the wheel still until rim 117 is again intentionally rotated.
It will now be appreciated that in an autobraking embodiment of the invention, when the brake is off then the wheelchair operates entirely as a conventional manual chair. The user strokes the wheel rim to drive the chair. When the brake is set, then the wheelchair acts as if the brake is set similar to in a conventional chair. The wheelchair is kept in place. But if the driving rim is stroked then the wheelchair is propelled via the torque-amplifying hub transmission of the invention. The result is that the wheelchair can traverse a steep incline or decline and as soon as the user stops driving the rim, the wheelchair safely comes to a stop. Now threatening hills and steep ramps can be safely traversed at any rate, slow or fast, even with a rest stop in the middle. With the hub transmission of the invention thus engaged, there can be no runaway.
Where the invention has a speed reducer in the hub, driving through it is just like using low gear on a bike. Compared to a conventional wheelchair trying to go up a steep incline, the hub makes it much easier on the muscles—and feels it—because the speed reduction and torque amplification. The strong user would use conventional propulsion when rolling on level ground. But when easier propulsion or self-braking is important, the user puts the brakes on and then uses the drive rim of the hub for propulsion
The automatic safety and security of the self-braking feature also gives a greater level of confidence to the user. As well, the mechanical advantage in the hub can be so effective as to make it possible for a user to propel up an incline that heretofore was considered insurmountable. Or this mechanical advantage may benefit an aged or enfeebled user even on a level surface. In any event, the hub invention can extend the range of mobility of the conventional manual wheelchair and its user. The present invention results in increased mobility in an easy to use and cost-effective wheel design for any wheelchair, new or retrofit.
Since athletic events for the wheelchair-bound are becoming more popular, there is a variation on the above theme that is part of the invention. Rather than a speed reducer hub, we implement a speed increaser hub for a racing wheelchair, where the user can select a high-speed overdrive mode to increase the top-end speed achievable by the racer. In this case the speed increaser is used for much like a high gear in an automobile. One shift mechanism can be used to shift both wheels simultaneously on-the-fly. There is no auto-braking feature in this embodiment. A separate brake assembly is required for braking.
FIG. 11 shows a speed increaser 121 ″ of the nested cam gear type. This is applied to the configuration of FIG. 3 . If the speed converter 121 is a back-drivable speed increaser, then the second mode is a speed-up overdrive mode for the athletic racer, without the automatic braking function. In position A of the shifter, the drive is 1:1, and in position B, the drive is 1:n speed increaser. There are ten teeth on the inner cam gear 214 and five teeth on the outer cam gear 212 , such that at 5:10 or 1:2 speed increase is achieved in this example. The drive is backdriveable and does not perform a braking function.
The foregoing embodiments are examples of the invention and are disclosed by way of illustration not limitation. Various modifications of the specific embodiments set forth above are within the spirit and scope of the invention. The scope of these and other embodiments is limited only as set forth in the following claims. | A wheel transmission for mobility vehicle includes an input component capable movement at a first rate of motion for selectively driving an output component at either the first rate of motion or a second rate of motion. Operably connected between the input component and the output component is a conversion apparatus which enables the selective drive between the input component and the output component to take place. In addition, the conversion apparatus is capable of preventing the output component from being backdrivable, and thereby acting as a brake, when the vehicle is at rest. | 0 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority benefit of French patent application number 09/53922, filed on Jun. 12, 2009, entitled “CIRCUIT FOR CONTROLLING A LIGHTING UNIT WITH LIGHT-EMITTING DIODES,” which is hereby incorporated by reference to the maximum extent allowable by law.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to lighting units with light-emitting diodes intended to receive an A.C. supply voltage. It more specifically relates to circuits for powering such devices.
[0004] 2. Discussion of the Related Art
[0005] For a long time, illumination devices have been formed based on incandescent light bulbs or on fluorescent tubes capable of receiving an A.C. supply voltage, for example, a 220-V mains voltage at 50 Hz. More recently, it has been desired to use light-emitting diodes. Such diodes especially have a long lifetime and a high light output. They however require a power supply circuit capable of receiving the A.C. voltage from the mains.
[0006] Conventional circuits operate in linear mode, that is, they provide a D.C. voltage and a power adapted to the electrical characteristics of the diodes. The diodes are then maintained on for the entire duration of each halfwave of the mains voltage. This power supply mode has the disadvantage of decreasing their lifetime. Further, linear power supply circuits generally comprise high-voltage capacitors having the disadvantage of being expensive and bulky.
SUMMARY OF THE INVENTION
[0007] An object of an embodiment of the present invention is to overcome all or part of the disadvantages of circuits for powering light-emitting diodes.
[0008] An object of an embodiment of the present invention is to provide such a circuit improving the lifetime of the diodes.
[0009] An object of an embodiment of the present invention is to provide such a circuit which has low cost and is easy to form.
[0010] Thus, an embodiment of the present invention provides a circuit capable of receiving, in series with at least one light-emitting diode, a rectified A.C. voltage, comprising: a first gate turn-off thyristor connected to first and second terminals of the circuit; and a control circuit for turning off the first thyristor when the voltage between the first and second terminals exceeds a threshold.
[0011] According to an embodiment of the present invention, said circuit capable of receiving, in series with at least one light-emitting diode, a rectified A.C. voltage, comprises a second thyristor connecting the gate of the first thyristor to said second terminal; and a first resistive element connecting the gate of the first thyristor to said first terminal or to a terminal of application of the rectified A.C. voltage.
[0012] According to an embodiment of the present invention, said circuit capable of receiving, in series with at least on light-emitting diode, a rectified A.C. voltage, comprises, in series with the first thyristor, a voltage dividing bridge for setting said threshold, the midpoint of the voltage dividing bridge being connected to a gate of the second thyristor.
[0013] According to an embodiment of the present invention, said circuit capable of receiving, in series with at least one light-emitting diode, a rectified A.C. voltage, further comprises a circuit of temporary power storage between the midpoint of the voltage dividing bridge and said gate of the second thyristor.
[0014] According to an embodiment of the present invention, said storage circuit comprises: a second resistive element in series with a capacitive storage element, connecting said gate of the second thyristor to said second terminal; and a diode connecting the midpoint of the voltage dividing bridge to said gate of the second thyristor.
[0015] According to an embodiment of the present invention, the resistivity of said voltage dividing bridge is low as compared to the resistivity of the first resistive element.
[0016] According to an embodiment of the present invention, a capacitive electromagnetic disturbance attenuation element is connected between said first and second terminals.
[0017] According to an embodiment of the present invention, the first thyristor is maintained on at the beginning of each halfwave of said rectified A.C. voltage, for a period ranging between 5% and 30% of the duration of said halfwave.
[0018] An embodiment of the present invention further provides an illumination device intended to receive an A.C. voltage comprising: a bridge for rectifying the A.C. voltage; at least one light-emitting diode; and a circuit capable of receiving, in series with at least one light-emitting diode, a rectified A.C. voltage, according to any of the above-mentioned embodiments, series-connected with said at least one light-emitting diode, between output terminals of said rectifying bridge.
[0019] According to an embodiment of the present invention, said circuit capable of receiving, in series with at least one light-emitting diode, a rectified A.C. voltage, forms a dipole.
[0020] The foregoing objects, features, and advantages of the present invention will be discussed in detail in the following non-limiting description of specific embodiments in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 schematically shows an illumination device with light-emitting diodes;
[0022] FIG. 2 shows the simplified electric diagram of the illumination device of FIG. 1 ;
[0023] FIG. 3 shows the simplified electric diagram of the illumination device of FIG. 1 ; and
[0024] FIGS. 4A to 4G are simplified timing diagrams illustrating the operation of the illumination device of FIG. 3 .
DETAILED DESCRIPTION
[0025] For clarity, the same elements have been designated with the same reference numerals in the different drawings. Further, the timing diagrams of FIGS. 4A to 4G are not to scale.
[0026] FIG. 1 is a simplified view of an illumination device 1 with light-emitting diodes 3 .
[0027] FIG. 2 is a simplified electric diagram of device 1 .
[0028] Device 1 comprises an assembly of light-emitting diodes 3 in series. Terminals A and C ( FIG. 2 ) of diode assembly 3 are connected to a power supply circuit 5 (POWER). In the shown example, terminals A and C respectively correspond to the anode and cathode connection terminals of the assembly of diodes 3 in series.
[0029] Circuit 5 is capable of receiving an A.C. voltage V AC ( FIG. 2 ), for example, the mains voltage, and of providing a power adapted to the electrical characteristics of the assembly of diodes 3 . Input terminals of power supply circuit 5 are connected to terminals E and F of a base 6 . Base 6 may have any shape adapted to a connection on a socket, for example, a screw thread. Other connections may be provided, for example, a direct wiring to a power supply connector. The entire device is assembled in a package 7 only leaving access to base 6 and diodes 3 . Transparent glass, not shown, may protect diodes 3 .
[0030] A switch 9 is generally provided, for example, between a terminal of application of the phase of mains voltage V AC and terminal E of base 6 , to control the powering-on of device 1 . Switch 9 may correspond to a wall switch that may be actuated by a user.
[0031] To improve the lifetime and the efficiency of the diodes, it is provided to maintain them on for a fraction only of each period of the mains voltage, which is sufficient, in relation with the eye's persistence of vision, to guarantee a continuous illumination.
[0032] Thus, an aspect of an embodiment of the present invention is to provide a power supply circuit capable of providing a pulse control signal, the electric power received by the diodes depending on the duration of the pulse.
[0033] FIG. 3 is the electric diagram of an embodiment of the illumination device of FIG. 2 showing power supply circuit 5 in more detailed fashion.
[0034] Terminals E and F of the base are connected to A.C. input terminals of a fullwave rectifying bridge 20 capable of providing, between high and low output terminals H and M, a rectified A.C. voltage V ACR . Terminal M for example corresponds to the reference voltage terminal of the circuit or ground. In the shown example, bridge 20 comprises four diodes 21 , 23 , 25 , and 27 .
[0035] In this example, power supply circuit 5 further comprises a dipole or control circuit 31 connected, in series with diode assembly 3 , between output terminals H and M of rectifying bridge 20 . Terminal A of diode assembly 3 is connected to terminal H. Terminals I and J of dipole 31 are respectively connected to terminal C of diode assembly 3 and to terminal M.
[0036] Circuit 31 comprises a gate turn-off thyristor 33 having its anode connected to terminal I. A voltage dividing bridge formed, for example, of two resistors 35 and 37 in series, is connected between the cathode of thyristor 33 and terminal J. A resistor 39 , of strong value with respect to resistors 35 and 37 , is connected between the anode and the gate of thyristor 33 . Resistor 39 is used to turn on thyristor 33 at the beginning of each halfwave of voltage V ACR . A cathode gate thyristor 41 is forward connected between the gate of thyristor 33 and terminal J for controlling the turning off of thyristor 33 . The voltage dividing bridge conditions the turning on of thyristor 41 .
[0037] For the case where thyristor 41 would not be fast enough, a temporary power storage circuit is preferably provided. This circuit, for example, comprises a resistor 43 , series connected with a capacitor 45 , between the gate of thyristor 41 and terminal J, and a diode 47 , forward connected between the midpoint of the voltage dividing bridge and the gate of thyristor 41 .
[0038] Optionally, a capacitor 49 connects terminal I to terminal J, to attenuate electromagnetic disturbances linked to the switching of thyristors 33 and 41 .
[0039] Power supply circuit 5 may further comprise, between its input terminals E and F, a varistor 29 of protection against possible overvoltages.
[0040] As a specific embodiment:
[0041] resistances 37 and 43 are on the order of a few tens of Ω, for example, on the order of 10Ω;
[0042] resistance 35 is on the order of a few hundreds of Ω, for example, on the order of 250Ω;
[0043] resistance 39 is on the order of a few tens of kΩ, for example, on the order of 75Ω;
[0044] capacitance 45 is on the order of a few hundreds of nF, for example, on the order of 100 nF; and
[0045] capacitance 49 is on the order of a few tens of nF, for example, on the order of 10 nF.
[0046] FIGS. 4A to 4G are simplified timing diagrams showing examples of the variation of the voltages and currents at different points of the illumination device of FIG. 3 . FIG. 4A shows the variation of rectified A.C. voltage V ACR . FIG. 4B shows the variation of current I 33 flowing through thyristor 33 . FIG. 4C shows the variation of current I G41 flowing between the cathode gate and the cathode of thyristor 41 . FIG. 4D shows the variation of voltage V 41 across thyristor 41 . FIG. 4E shows the variation of current I 41 flowing through thyristor 41 . FIG. 4F shows the variation of current I LED flowing through diode assembly 3 . FIG. 4G shows the variation of voltage V CM between terminals C and M.
[0047] A steady state is assumed, that is, switch 9 is assumed to be on.
[0048] At a time t 0 of beginning of a halfwave of voltage V ACR , thyristor 41 is off. A current flows through diodes 3 , resistor 39 , the gate of thyristor 33 , and resistors 35 and 37 . Thyristor 33 thus starts conducting. A conduction path is thus established between terminal A and the ground, running through diode assembly 3 , thyristor 33 , and resistors 35 and 37 of low value of the voltage dividing bridge. The diodes turn on. Current I LED is then equal to current I 33 .
[0049] From time t 0 , gate current I G41 of thyristor 41 increases proportionally to current I 33 , to within a factor especially depending on the value of resistors 35 and 37 of the voltage dividing bridge. A current for charging capacitor 45 further flows between the cathode of diode 47 and terminal M. Voltage V 41 across thyristor 41 is equal to rectified voltage V ACR minus the voltage drop caused by diode assembly 3 and by resistor 39 . Voltage V CM is equal to rectified voltage V ACR minus the voltage drop of diode assembly 3 .
[0050] At a time t 1 , current I G41 reaches a turn-on threshold I TH of thyristor 41 . The turning on of thyristor 41 brings the gate of thyristor 33 to ground (V 41 =0 V), thus turning it off. Current I 33 flowing through thyristor 33 thus becomes zero. There then is a conduction path between terminal A of diode assembly 3 and terminal M, running through diode assembly 3 , resistor 39 , and thyristor 41 . At time t 1 , current I LED becomes equal to current I 41 . The value of resistor 39 is selected to be sufficiently high for this current to be very low (it is shown as being zero in FIG. 4F ). Thus, diodes 3 turn off substantially at time t 1 . The values of resistors 35 and 37 of the voltage dividing bridge define the threshold of voltage V ACR for which current I G41 reaches turn-on threshold I TH of thyristor 41 . The values of resistors 35 and 37 are for example selected so that the time for which diodes 3 are on ranges between 5% and 30% of duration T of a halfwave of rectified voltage V ACR . Further, at time t 1 , voltage V CM is abruptly taken up to the value of voltage V ACR (neglecting the voltage drop in diodes 3 with respect to the voltage drop in resistor 39 ).
[0051] To ensure the priming of thyristor 41 , capacitor 45 maintains a non-zero current I G41 for some time after time t 1 .
[0052] Thyristor 41 remains conductive until the current that it conducts cancels, that is, until end time t 0 +T of the halfwave. Thus, diodes 3 are maintained off between times t 1 and t 0 +T.
[0053] In a transient state of turning on of switch 9 , this turning on may occur at any time of the halfwave. Thyristor 33 turns on at this time but current I G41 immediately reaches turn-on threshold I TH of thyristor 41 , thus turning off of thyristor 33 and turning off diodes 3 until the beginning of the next halfwave. This enables the diodes to see across their terminals a voltage close to the maximum mains voltage for a very short time, thus avoiding their destruction. The diodes are thus protected.
[0054] The use of a fullwave rectifying bridge provides a frequency of the diode control pulses equal to twice the frequency of the A.C. power supply voltage. Such a frequency is sufficient to get rid of possible flickering effects with a mains voltage of 50 Hz or 60 Hz.
[0055] An advantage of the provided circuit is that it has a low cost, a small bulk, and is easy to form.
[0056] To form a power supply circuit capable of providing a pulse control signal, it could have been devised to use, instead of gate turn-off thyristor 33 , a gate turn-on thyristor. This thyristor would then have to be turned on at a time close to the end of each halfwave of the rectified voltage, the diodes remaining substantially conductive until the end of each halfwave. However, spurious voltage peaks may appear, in particular at the turning on of switch 9 . Such peaks would be capable of causing the turning-on of the diode turn on thyristor. In this case, the diodes would remain on substantially until the end of the halfwave. If switch 9 had been turned on, for example, at the beginning of a halfwave, the diodes would receive a much greater power than that for which they have been provided, which would cause their destruction.
[0057] Specific embodiments of the present invention have been described. Various alterations and modifications will occur to those skilled in the art. In particular, the present invention applies whatever the available A.C. supply voltage. Further, the number of light-emitting diodes and their connection may vary.
[0058] Further, the illumination device may comprise a dimming function if one of the resistors of the voltage dividing bridge is replaced with a variable resistor.
[0059] Moreover, in the circuit described in relation with FIG. 3 , terminals A and C of the assembly of light-emitting diodes are respectively connected to terminal H, corresponding to the high terminal of the rectified supply voltage, and to anode terminal I of gate turn-off thyristor 33 . According to an alternative embodiment, resistor 37 is connected to terminal M, no longer directly but via diode assembly 3 . According to another variation, resistor 39 is no longer connected to terminal C but to terminal H. Such variations may be combined.
[0060] Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and the scope of the present invention. Accordingly, the foregoing description is by way of example only and is not intended to be limiting. The present invention is limited only as defined in the following claims and the equivalents thereto. | A circuit capable of receiving, in series with at least one light-emitting diode, a rectified A.C. voltage, comprising: a first gate turn-off thyristor connected to first and second terminals of the circuit; and a control circuit for turning off the first thyristor when the voltage between the first and second terminals exceeds a threshold. | 8 |
CROSS-REFERENCE
[0001] This application claims priority to U.S. Ser. No. 14/472,030, filed Aug. 28, 2014, which claims the benefit of U.S. Provisional Patent Application No. 61/871,251 filed Aug. 28, 2013 entitled “METHOD AND APPARATUS FOR CREATING SOFTWARE DEFINED ROUTING MESHED NETWORKS THROUGH A tELASTIC MESH CONTROLLER”, and claims the benefit of U.S. Provisional Patent Application No. 61/871,308 filed Aug. 29, 2013 entitled “METHOD AND APPARATUS FOR CREATING SOFTWARE DEFINED CLOUD COLLISION DOMAIN NETWORKS THROUGH A tELASTIC BRIDGE CONTROLLER”; the contents of which are all herein incorporated by reference in its entirety.
FIELD
[0002] The disclosure generally relates to enterprise cloud computing and more specifically to a seamless cloud across multiple clouds providing enterprises with quickly scalable, secure, multi-tenant automation.
BACKGROUND
[0003] Cloud computing is a model for enabling on-demand network access to a shared pool of configurable computing resources/service groups (e.g., networks, servers, storage, applications, and services) that can ideally be provisioned and released with minimal management effort or service provider interaction.
[0004] Software as a Service (SaaS) provides the user with the capability to use a service provider's applications running on a cloud infrastructure. The applications are accessible from various client devices through either a thin client interface, such as a web browser or a program interface. The user does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities.
[0005] Infrastructure as a Service (IaaS) provides the user with the capability to provision processing, storage, networks, and other fundamental computing resources where the user is able to deploy and run arbitrary software, which can include operating systems and applications. The user does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, and deployed applications; and possibly limited control of select networking components (e.g., host firewalls).
[0006] Platform as a Service (PaaS) provides the user with the capability to deploy onto the cloud infrastructure user-created or acquired applications created using programming languages, libraries, services, and tools supported by the provider. The user does not manage or control the underlying cloud infrastructure including network, servers, operating systems, or storage, but has control over the deployed applications and possibly configuration settings for the application-hosting environment.
[0007] Cloud deployment may be Public, Private or Hybrid. A Public Cloud infrastructure is provisioned for open use by the general public. It may be owned, managed, and operated by a business, academic, or government organization. It exists on the premises of the cloud provider. A Private Cloud infrastructure is provisioned for exclusive use by a single organization comprising multiple users (e.g., business units). It may be owned, managed, and operated by the organization, a third party, or some combination of them, and it may exist on or off premises. A Hybrid Cloud infrastructure is provisioned for exclusive use by a single organization comprising multiple users (e.g., business units). It may be owned, managed, and operated by the organization, a third party, or some combination of them, and it may exist on or off premises.
[0008] The promise of enterprise cloud computing was supposed to lower capital and operating costs and increase flexibility for the Information Technology (IT) department. However lengthy delays, cost overruns, security concerns, and loss of budget control have plagued the IT department. Enterprise users must juggle multiple cloud setups and configurations, along with aligning public and private clouds to work together seamlessly. Turning up of cloud capacity (cloud stacks) can take months and many engineering hours to construct and maintain. High-dollar professional services are driving up the total cost of ownership dramatically. The current marketplace includes different ways of private cloud build-outs. Some build internally hosted private clouds while others emphasize Software-Defined Networking (SDN) controllers that relegate switches and routers to mere plumbing.
[0009] The cloud automation market breaks down into several types of vendors, ranging from IT operations management (ITOM) providers, limited by their complexity, to so-called fabric-based infrastructure vendors that lack breadth and depth in IT operations and service. To date, true value in enterprise cloud has remained elusive, just out of reach for most organizations. No vendor provides a complete Cloud Management Platform (CMP) solution.
[0010] Therefore there is a need for systems and methods that create a unified fabric on top of multiple clouds reducing costs and providing limitless agility.
SUMMARY OF THE INVENTION
[0011] Additional features and advantages of the disclosure will be set forth in the description which follows, and will become apparent from the description, or can be learned by practice of the herein disclosed principles by those skilled in the art. The features and advantages of the disclosure can be realized and obtained by means of the disclosed instrumentalities and combinations as set forth in detail herein. These and other features of the disclosure will become more fully apparent from the following description, or can be learned by the practice of the principles set forth herein.
[0012] A Cloud Management Platform is described for fully unified compute and virtualized software-based networking components empowering enterprises with quickly scalable, secure, multi-tenant automation across clouds of any type, for clients from any segment, across geographically dispersed data centers.
[0013] In one embodiment, systems and methods are described for sampling of data center devices alerts; selecting an appropriate response for the event; monitoring the end node for repeat activity; and monitoring remotely.
[0014] In another embodiment, systems and methods are described for discovery of compute nodes; assessment of type, capability, VLAN, security, virtualization configuration of the discovered compute nodes; configuration of nodes covering add, delete, modify, scale; and rapid roll out of nodes across data centers.
[0015] In another embodiment, systems and methods are described for discovery of network components including routers, switches, server load balancers, firewalls; assessment of type, capability, VLAN, security, access lists, policies, virtualization configuration of the discovered network components; configuration of components covering add, delete, modify, scale; and rapid roll out of network atomic units and components across data centers.
[0016] In another embodiment, systems and methods are described for discovery of storage components including storage arrays, disks, SAN switches, NAS devices; assessment of type, capability, VLAN, VSAN, security, access lists, policies, virtualization configuration of the discovered storage components; configuration of components covering add, delete, modify, scale; and rapid roll out of storage atomic units and components across data centers.
[0017] In another embodiment, systems and methods are described for discovery of workload and application components within data centers; assessment of type, capability, IP, TCP, bandwidth usage, threads, security, access lists, policies, virtualization configuration of the discovered application components; real time monitoring of the application components across data centers public or private; and capacity analysis and intelligence to adjust underlying infrastructure thus enabling liquid applications.
[0018] In another embodiment, systems and methods are described for analysis of capacity of workload and application components across public and private data centers and clouds; assessment of available infrastructure components across the data centers and clouds; real time roll out and orchestration of application components across data centers public or private; and rapid configurations of all needed infrastructure components.
[0019] In another embodiment, systems and methods are described for analysis of capacity of workload and application components across public and private data centers and clouds; assessment of available infrastructure components across the data centers and clouds; comparison of capacity with availability; real time roll out and orchestration of application components across data centers public or private within allowed threshold bringing about true elastic behavior; and rapid configurations of all needed infrastructure components.
[0020] In another embodiment, systems and methods are described for analysis of all remote monitored data from diverse public and private data centers associated with a particular user; assessment of the analysis and linking it to the user applications; alerting user with one line message for high priority events; and additional business metrics and return on investment addition in the user configured parameters of the analytics.
[0021] In another embodiment, systems and methods are described for discovery of compute nodes, network components across data centers, both public and private for a user; assessment of type, capability, VLAN, security, virtualization configuration of the discovered unified infrastructure nodes and components; configuration of nodes and components covering add, delete, modify, scale; and rapid roll out of nodes and components across data centers both public and private.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to describe the manner in which the above-recited and other advantages and features of the disclosure can be obtained, a more particular description of the principles briefly described above will be rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. Understanding that these drawings depict only exemplary embodiments of the disclosure and are not therefore to be considered to be limiting of its scope, the principles herein are described and explained with additional specificity and detail through the use of the accompanying drawings in which:
[0023] FIG. 1 is a block diagram of an exemplary hardware configuration in accordance with the principles of the present invention;
[0024] FIG. 2 is a block diagram describing a tenancy configuration wherein the Enterprise hosts systems and methods within its own data center in accordance with the principles of the present invention;
[0025] FIG. 3 is a block diagram describing a super tenancy configuration wherein the Enterprise uses systems and methods hosted in a cloud computing service in accordance with the principles of the present invention;
[0026] FIG. 4 is a logical diagram of the Enterprise depicted in FIG. 1 in accordance with the principles of the present invention;
[0027] FIG. 5 illustrates a logical view that an Enterprise administrator and Enterprise user have of the uCloud Platform depicted in FIG. 1 in accordance with the principles of the present invention;
[0028] FIG. 6 illustrates a flow diagram of a service catalog classifying data center resources into service groups; selecting a service group and assigning it to end users;
[0029] FIG. 7 illustrates a flow diagram of mapping service group categories to user groups that have been given access to a given service group, in accordance with the principles of the present invention;
[0030] FIG. 8 illustrates the Cloud administration process utilizing the tenant cloud instance manager as well as the manager of manager and the ability of uCloud platform to logically restrict and widen scope of Cloud Administration, as well as monitoring;
[0031] FIG. 9 illustrates a hierarchy diagram of the Cloud administration process utilizing the tenant cloud instance manager as well as the manager of manager and the ability of uCloud platform to logically restrict and widen scope of Cloud Administration in accordance with the principles of the present invention;
[0032] FIG. 10 illustrates the logical flow of information from the uCloud Platform depicted in FIG. 1 to a Controller Node in a given Enterprise for compute nodes;
[0033] FIG. 11 illustrates the logical flow of information from the uCloud Platform depicted in FIG. 1 to the Controller Node in a given Enterprise for network components;
[0034] FIG. 12 illustrates the logical flow of information from the uCloud Platform to the Controller Node in a given Enterprise for storage devices;
[0035] FIG. 13 illustrates the application-monitoring component of the uCloud Platform in accordance with the principles of the present invention;
[0036] FIG. 14 illustrates the application-orchestration component of the uCloud Platform in accordance with the principles of the present invention;
[0037] FIG. 15 illustrates the integration of the application-orchestration and application-monitoring components of the uCloud Platform in accordance with the principles of the present invention;
[0038] FIG. 16 illustrates the big data component of the uCloud Platform depicted in FIG. 1 and the relationship to the monitoring component of the platform
[0039] FIG. 17 illustrates the process of deploying uCloud within an Enterprise environment;
[0040] FIG. 18 illustrates a flow diagram in accordance with the principles of the present invention;
[0041] FIG. 19 illustrates a flow diagram in accordance with the principles of the present invention;
[0042] FIG. 20 illustrates a flow diagram in accordance with the principles of the present invention;
[0043] FIG. 21 illustrates a flow diagram in accordance with the principles of the present invention;
[0044] FIG. 22 illustrates a block diagram in accordance with the principles of the present invention; and
[0045] FIG. 23 illustrates a combined block and flow diagram in accordance with the principles of the present invention.
DETAILED DESCRIPTION
[0046] The FIGURES and text below, and the various embodiments used to describe the principles of the present invention are by way of illustration only and are not to be construed in any way to limit the scope of the invention. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims. A Person Having Ordinary Skill in the Art (PHOSITA) will readily recognize that the principles of the present invention maybe implemented in any type of suitably arranged device or system. Specifically, while the present invention is described with respect to use in cloud computing services and Enterprise hosting, a PHOSITA will readily recognize other types of networks and other applications without departing from the scope of the present invention.
[0047] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by a PHOSITA to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, a limited number of the exemplary methods and materials are described herein.
[0048] All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates, which may need to be independently confirmed.
[0049] Reference is now made to FIG. 1 that depicts a block diagram of an exemplary hardware configuration in accordance with the principles of the present invention. A uCloud Platform 100 combining self-service cloud orchestration with a Layer 2- and Layer 3-capable encrypted virtual network may be hosted by a cloud computing service such as but not limited to, Amazon Web Services or directly by an enterprise such as but not limited to, a service provider (e.g. Verizon or AT&T), provides a web interface 104 with a Virtual IP (VIP) address, a Rest API interface 106 with a Virtual IP (VIP), a RPM Repository Download Server and, a message bus 110 , and a vAppliance Download Manager 112 . Connections to and from web interface 104 , Rest API interface 106 , RPM Repository Download Server, message bus 110 , and vAppliance Download Manager 112 are preferably SSL secured. Interfaces 104 , 106 , 107 and 109 are preferably VeriSign certificate based with Extra Validation (EV), allowing for 128-bit encryption and third party validation for all communication on the interfaces. In addition to SSL encryption on Message BUS 110 , each message sent across on interface 107 to a Tenant environment is preferably encrypted with a Public/Private key pair thus allowing for extra security per Enterprise/Service Provider communication. The Public/Private key pair security per Tenant prevents accidental information leakage to be shared across other Tenants. Interfaces 108 and 110 are preferably SSL based (with self-signed) certificates with 128-bit encryption. In addition to communication interfaces, all Tenant passwords and Credit Card information stored are preferably encrypted.
[0050] Controller node 121 performs dispatched control, monitoring control and Xen Control. Dispatched control entails executing, or terminating, instructions received from the uCLoud Platform 100 . Xen control is the process of translating instructions received from uCLoud Platform 100 into a Xen Hypervisor API. Monitoring is performed by the monitor controller by periodically gathering management plane information data in an extended platform for memory, CPU, network, and storage utilizations. This information is gathered and then sent to the management plane. The extended platform comprises vAppliance instances that allow instantiation of Software Defined clouds. The management, control, and data planes in the tenant environment are contained within the extended platform. RPM Repository Download Server 108 downloads RPMs (packages of files that contain a programmatic installation guide for the resources contained) when initiated by Control node 121 . The message bus VIP 110 couples between the Enterprise 101 and the uCloud Platform 100 . A Software Defined Cloud (SDC) may comprise a plurality of Virtual Machines (vAppliances) such as, but not limited to a Bridge Router (BR-RTR, Router, Firewall, and DHCP-DNS (DDNS) across multiple virtual local area networks (VLANs) and potentially across data centers for scale, coupled through Compute node (C-N) nodes (aka servers) 120 a - 120 n. The SDC represents a logical linking of select compute nodes (aka servers) within the enterprise cloud. Virtual Networks running on Software Defined Routers 122 and Demilitarized Zone (DMZ) Firewalls are referred to as vAppliances. All Software defined networking components are dynamic and automated, provisioned as needed by the business policies defined in the Service Catalogue by the Tenant Administrator.
[0051] The uCloud Platform 100 supports policy-based placement of vAppliances and compute nodes ( 120 a - 120 n ). The policies permit the Tenant Administrator to do auto or static placement thus facilitating creation of dedicated hardware environment Nodes for Tenant's Virtual Machine networking deployment base.
[0052] The uCloud Platform 100 created SDC environment enables the Tenant Administrator to create lines of businesses or in other words, department groups with segregated networked space and service offerings. This facilitates Tenant departments like IT, Finance and development to all share the same SDC space but at the same time be isolated by networking and service offerings.
[0053] The uCloud Platform 100 supports deploying SDC vAppliances in redundant pair topologies. This allows for key virtual networking building block host nodes to be swapped out and new functional host nodes be inserted managed through uCloud Platform 100 . SDCs can be dedicated to data centers, thus two unique SDCs in different data centers can provide the Enterprise a disaster recovery scenario.
[0054] SDC vAppliances are used for the logical configuration of SDC's within a tenants private cloud. A Router Node is a physical server, or node, in an tenant's private cloud that may be used to host certain vAppliances relating SDC networking Such vAppliances may include the Router, DDNS, and BR-RTR (Bridge Router) vApplications that may be used to route internet traffic to and from an SDC, as well as establish logical boundaries for SDC accessibility. Two Router Nodes exist, an active Node (-A) and a standby Node (-S), used in the event that the active node experiences failure. The Firewall Nodes, also present in an active and standby pair, are used to filter internet traffic coming into an SDC. There is a singular vAppliance that uses the Firewall Node, that being the Firewall vAppliance. The vAppliances are configured through use of vAppliance templates, which are downloaded and stored by the tenant in the appliance store/Template store.
[0055] Reference is now made to FIG. 2 depicting a block diagram describing a tenancy configuration wherein the Enterprise hosts systems and methods within its own data center in accordance with the principles of the present invention. The uCloud platform 100 is hosted directly on an enterprise 200 which may be a Service Provider such as, but not limited to, Verizon FIOS or AT&T uVerse, which serves tenants A-n 202 , 204 and 206 , respectively. Alternatively, enterprise 200 may be an enterprise having subsidiaries or departments 202 , 204 and 206 that it chooses to keep segregated.
[0056] Reference is now made to FIG. 3 depicting a block diagram of a super tenancy configuration wherein the Enterprise uses systems and methods hosted in a cloud computing service 300 in accordance with the principles of the present invention. In this configuration, the uCloud platform is hosted by a cloud computing service 300 that services Enterprises 302 , 304 and 306 . It should be understood that more or less Enterprises could be serviced without departing from the scope of the invention. In the present example, Enterprise C 306 has sub tenants. Enterprise C 306 may be a service provider (e.g. Verizon FIOS or AT&T u-Verse) or an Enterprise having subsidiaries or departments that it chooses to keep segregated.
[0057] Reference is now made to FIG. 4 depicting a block diagram describing permutations of a Software Defined Cloud (SDC) in accordance with the principles of the present invention. The SDC can be of three types namely Routed 400 , Public Routed 402 and Public 404 . Routed and Routed Public SDC types 400 and 402 respectively are designed to be reachable through the Enterprise IP address space, with the caveat that the Enterprise IP address space cannot be in the same collision domain as these types of SDC IP network space. Furthermore, Routed and Public Routed SDC 400 and 402 respectively can re-use same IP network space without colliding with each other. The Public SDC 404 is Internet 406 facing only, it can have overlapping collision IP space with the Enterprise network. Public SDC 404 further provides Internet facing access only. SDC IP schema is automatically managed by the uCloud platform 100 and does not require Tenant Administrator intervention.
[0058] SDC Software Defined Firewalls 408 are of two/one type, Internet gateway (for DMZ use). The SDC vAppliances (e.g. Firewall 408 , Router 410 ) and compute nodes ( 120 a - 120 n ) provide a scalable Cloud deployment environment for the Enterprise. The scalability is achieved through round robin and dedicated hypervisor host nodes. The host pool provisioning management is performed through uCloud Platform 100 . The uCloud Platform 100 manages dedicated nodes for the compute nodes ( 120 a - 120 n ), it allows for fault isolation across the Tenant's Virtual Machine workload deployment base.
[0059] Referring back to FIG. 1 , an uCloud Platform administrator 102 A, an Enterprise administrator 102 B, and an Enterprise User 102 C without administrator privileges are depicted. To deploy uCloud platform 100 , Enterprise administrator 102 B grants uCloud Platform administrator 102 A information regarding the enterprise environment 101 and the hardware residing within it (e.g. compute nodes 120 a - n ). After this information is supplied, platform 100 creates a customized package that contains a Controller Node 121 designed for the Enterprise 101 . Enterprise administrator 102 B downloads and install Controller Node 121 into the Enterprise environment 101 . The uCloud Platform 100 then generates a series of tasks, and communicates these tasks indirectly with Controller Node 121 , via the internet 111 . The communication is preferably done indirectly so as to eliminate any potential for unauthorized access to the Enterprise's information. The process preferably requires uCloud platform 100 to leave the tasks in an online location, and the tasks are only accessible to the unique Controller Node 121 present in an Enterprise Environment 101 . Controller Node 121 then fulfills the tasks generated by uCloud platform 100 , and thus configures the compute 122 , network 123 , and storage 120 a - n capability of the Enterprise environment 101 .
[0060] Upon completion of the hardware configuration, uCloud platform 100 is deployed in the Enterprise environment 101 . The uCloud platform 100 monitors the Enterprise environment 101 and preferably communicates with Controller Node 121 indirectly. Enterprise administrator 102 B and Enterprise User 102 C use the online portal to access uCloud platform 100 and to operate their private cloud.
[0061] Software defined clouds (SDCs) are created within the uCloud platform 100 configured Enterprise 101 . Each SDC contains compute nodes that are logically linked to each other, as well as certain network and storage components (logical and physical) that create logical isolation for those compute nodes within the SDC. As discussed above, an enterprise 101 may create three types of SDC's: Routed 400 , Public Routed 402 , and Public 404 as depicted in FIG. 4 . The difference, as illustrated by FIG. 4 , is how each SDC is accessible to an Enterprise user 102 C.
[0062] Reference is now made to FIG. 5 that depicts a logical view of the uCloud Platform 100 that the Enterprise administrator 102 B and Enterprise user 102 C have in accordance with the principles of the present invention. Resources compute 502 , network 504 and storage 506 residing in a data center 507 are coupled to the service catalog 508 that classifies the resources into service groups 510 a - 510 n . A monitor 512 is coupled to the service catalog 508 and to a user 514 . User 514 is also coupled to service catalog 508 . Service catalog 508 is configured to designate various data center items (compute 502 , network 504 , and storage 506 ) as belonging to certain service groups 510 a - 510 n . The Service catalog 508 also maps the service groups to the appropriate User. Additionally, monitor 512 monitors and controls the service groups belonging to a specific User.
[0063] The service catalog 508 allows for a) the creation of User defined services: a service is a virtual application, or a category/group of virtual applications to be consumed by the Users or their environment, b) the creation of categories, c) the association of virtual appliances to categories, d) the entitlement of services to tenant administrator-defined User groups, and e) the Launch of services by Users through an app orchestrator. The service catalog 508 may then create service groups 510 a - 510 n. A service group is a classification of certain data center components e.g. compute Nodes, network Nodes, and storage Nodes.
[0064] Monitoring in FIG. 5 is done by periodically gathering management plane information data in the extended platform for memory, CPU, network, storage utilizations. This information is gathered and then sent to the management plane.
[0065] FIG. 6 illustrates a flow diagram of a service catalog classifying data center resources into service groups; selecting a service group and assigning it to end users. FIG. 7 illustrates a flow diagram of mapping service group categories to user groups that have been given access to a given service group, in accordance with the principles of the present invention.
[0066] Reference is now made to FIGS. 8 and 9 that illustrate the Cloud administration process its hierarchy respectively, utilizing the tenant cloud instance manager as well as the manager of manager and the ability of uCloud platform to logically restrict and widen scope of Cloud Administration as well as monitoring;
[0067] It should be noted that reference throughout the specification to “tenants” includes both enterprises and service providers as “super-tenants”. Each Software Defined Cloud (SDC) has a management plane, as well as a Data Plane and Control Plane. The Management plane provisions, configures, and operates the cloud instances. The Control plane creates and manages the static topology configuration across network and security domains. The Data plane is part of the network that carries user networking traffic. Together, these three planes govern the SDC's abilities and define the logical boundaries of a given SDC. The Manager of Manager 604 in uCLoud Platform 100 which is accessible only to the uCloud Platform administrator 102 A, manages the tenant cloud instance manager 706 ( FIG. 10 ) in every tenant private cloud. The hierarchy of this management is shown in FIG. 9 .
[0068] Referring now to FIGS. 10 , 11 and 12 , the tenant cloud instance manager 706 is responsible for overseeing the management planes of various SDC's as well as any other virtual Applications that the tenant is running in its compute Nodes, network components and storage devices, respectively. The uCloud Platform 100 generates commands related to the management of Compute Nodes 120 a - n based on tenant cloud instance manager 706 and extended platform orchestrator. The extended platform orchestrator is responsible for intelligently dispersing commands to create, manage, delete, or modify components of a tenant's uCloud platform 100 , or the extended platform based on predetermined logic. These commands are communicated indirectly to the Controller Node 121 of a specific Enterprise environment. The controller node 121 then accesses the compute Nodes 120 a - n and executes the commands. The launched cloud instance (SDC) management planes are depicted as 708 a - n in FIG. 10 . The ability of the tenant cloud instance manager 706 to modify and delete SDC management plane characteristics (compute, network, storage, Users, and business processes is provided over the internet 111 . Tenants (depicted in FIG. 3 as 302 , 304 and 306 ) each have a Tenant cloud instance manager 706 viewable to through the web interface 104 depicted in FIG. 1 .
[0069] Again with reference to FIG. 8 , the monitoring platform 602 is not limited to one controller but rather, its scope is all controllers within the platform. The monitoring done by the controller 512 ( FIG. 5 ) is performed in a limited capacity, periodically gathering management plane information data in the extended platform for memory, CPU, network, storage utilizations. This information is gathered and then sent to the tenant cloud instance manager 706 .
[0070] Centralized management view of all management planes across the tenants is provided to uCloud Platform administrator 102 A through the uCloud web interface 104 depicted in FIG. 1 .
[0071] Reference is now made to FIG. 11 illustrating the logical flow of information from the uCloud Platform 100 to the Controller Node in a given Enterprise. The uCloud Platform 100 generates commands related to the management of Network components 122 and 123 based on tenant cloud instance manager and extended platform orchestrator element. The extended platform orchestrator is responsible for intelligently dispersing commands to create, manage, delete, or modify components of 100 , or the extended platform based on predetermined logic. These commands are communicated indirectly to the Controller Node ( 121 in FIG. 1 ) of a specific Enterprise environment 101 . The controller node then accesses the pertinent router nodes, and within them, the pertinent vAppliances, and executes the commands.
[0072] Reference is now made to FIG. 12 illustrating the logical flow of information from the uCloud Platform to the Controller Node in a given Enterprise. The uCloud Platform 100 generates commands related to the management of Storage components tenant cloud instance manager and extended platform orchestrator. The extended platform orchestrator is responsible for intelligently dispersing commands to create, manage, delete, or modify components of 100 , or the extended platform based on predetermined logic. These commands are communicated indirectly to the Controller Node 121 of a specific Enterprise environment. The controller node then accesses the pertinent storage devices and executes the commands.
[0073] Reference is now made to FIG. 13 illustrating the application-monitoring component of the uCloud Platform 100 in accordance with the principles of the present invention. The platform indirectly communicates with the Controller Node which monitors the application health. This entails passively monitoring a) the state of Enterprise SDC's ( 400 , 402 , 404 in FIG. 4 ), and b) the capacity of the Enterprise infrastructure. The Controller Node also actively monitors the state of the processes initiated by the uCloud Platform and executed by the Controller Node. The Controller Node relays the status of the above components to the uCloud Platform monitoring component 1000 .
[0074] Reference is now made to FIG. 14 illustrating the application-orchestration component of the uCloud Platform in accordance with the principles of the present invention. The app orchestrator performs the process of tracking service offerings that are logically connected to SDC's. It takes the requests from the service catalog and deterministically retrieves information on what compute Nodes and vAppliances are part of a given SDC. It launches service catalog applications within the compute nodes that are connected to a targeted SDC.
[0000] The process is as follows:
1. receive request for launch of a virtual application from service catalog 508 .
2. retrieve information on destination of the request (which SDC in which tenant environment)
3. Retrieve information of what devices compute Nodes and vAppliances are involved in the SDC
4. once it determines the above, the app orchestrator sends a configuration to launch these virtual applications to the controller Node.
Additionally, the app orchestrator will be used in conjunction with the app monitor in the uCloud platform 100 as well as the monitoring controller present in the controller node in the extended platform to a) receive requests from controller node and b) access the relevant tenant extended platform, determines the impacted SDC, and c) perform appropriate corrective action.
[0075] Reference is now made to FIG. 15 illustrating the integration of the application-orchestration and application-monitoring components of the uCloud Platform in accordance with the principles of the present invention. FIG. 15 illustrates part of the Monitoring functionality of the uCLoud platform 100 . Through use of the monitoring controller, the app monitor collects health information of the extended platform (as detailed herein above). In addition, a tenant can define a “disruptive event”. In the event of a disruptive event the monitoring controller will alert the app orchestrator to perform corrective action. The monitoring controller performs corrective action by rebuilding relevant portions of extended platform control plane.
[0076] Reference is now made to FIG. 16 illustrating the big data component of the uCloud Platform 100 and the relationship to the monitoring component of the platform. Based on the data collected by the Controller Node 121 that is relayed to the Platform and stored in a Database, an analysis can be made of, a) SDC and compute nodes usage, and b) disruptive events reported. Heuristics of cloud usage is tracked by the Controller Node. Heuristic algorithmic analysis is used in 100 to understand aspects of tenant cloud usage.
[0000] SDC instance information is collected from the SDC management plane by the tenant cloud instance manager. (achieved by a) tenant cloud instance manager sending a command to the controller node via the message bus, b) controller node uses the command to retrieve collected information from the correct SDC management plane, c) information is relayed to tenant cloud instance manager, d) information is stored in a database)
SDC instance Information refers to Data about services usage, services types, SDC networking, compute, storage consumption data. This Data is collected continuously (via process outlined above) and archived to an external Big Data database ( 1303 , contained in 100 ).
Big data analytics engine processes the gathered information and performs heuristic big data analysis to determine cloud tenant services usage, services types, SDC networking, compute, storage consumption data, and then suggests optimal cloud deployment for tenant (through web interface in 100 ).
[0077] This analysis can contain a determination of high priority events, and report it to the relevant administrators 102 A, and 102 B. Additional analysis can be made using business metrics and return on investment computations.
[0078] Reference is now made to FIG. 17 illustrates the process of deploying uCloud within an Enterprise environment. Using gathered information on compute nodes 120 a - n , uCloud Platform 100 creates a customized package that contains a Controller Node 121 , designed for the Enterprise 101 . Administrator 102 B then downloads and installs Controller Node 121 into the Enterprise environment 101 . The uCloud Platform then orchestrates the infrastructure within the Enterprise environment, via the Controller Node. This includes configuration of router nodes 122 , firewall node 123 , compute Nodes 120 a - n , as well as any storage infrastructure.
[0079] FIG. 17 represents a holistic view of the cloud management platform capabilities of uCloud Platform. The platform is separated into the hosted platform 100 and the management platform.
[0080] The uCloud Platform 100 can support many tenants recalling that a tenant is defined as an enterprise or a service provider. The multi tenant concept can be seen in FIG. 2 , as well as in FIG. 3 . The tenant environment prior to deployment of uCloud is a collection of Compute Nodes. Post uCloud deployment, the environment, now called a private cloud, comprises an extended platform and compute nodes. The extended platform comprises of a limited number of Nodes dedicated for the logical creation of clouds (SDC's). The compute Nodes are used as Enterprise resources, and can be part of a single or multiple SDC's, or software defined clouds. The SDC concept is seen in FIG. 4 . This is referred to as the “logical view” of the private cloud. The division of the extended platform and the compute nodes is seen in FIG. 1 . This will be referred to as the “hardware view” of the private cloud. The combination of the logical and hardware views is seen in ( FIG. 18 ). As mentioned, the extended platform consists of several Nodes (servers). Each Node will run specific types of virtual Appliances, or vAppliances, that regulate and create logical boundaries for an SDC. Every SDC will contain a specific set of vAppliances. The shaded regions of (FLOW 1) represent exclusive use of a set of vAppliances by a specific SDC. The Compute Nodes of a private cloud, seen in FIG. 1 and in FLOW as C-N, are a resource that can be shared between multiple SDC's. This sharing concept is seen in FIG. 18 .
[0081] The uCloud Platform manages SDC's by providing several features that will assist a tenant in operating the private cloud. These features include, but are not restricted to, a) service catalog of virtual applications to be run on a given SDC, b) monitoring of SDC's, c) Big Data analytics of SDC usage and functionality, and d) hierarchical logic dictating access to SDC's/virtual applications/health information/or other sensitive information. The process of performing each feature has been shown in FIGS. 5-14 .
[0082] The uCloud Platform configuration process is summarized as follows: Using gathered information on compute nodes 120 a - n , uCloud Platform 100 creates a customized package that contains a Controller Node 121 , designed for the Enterprise 101 . 102 B then downloads and installs 121 into the Enterprise environment 101 . The uCloud Platform then orchestrates the infrastructure within the Enterprise environment, via the Controller Node. This includes configuration of router nodes 122 , firewall node 123 , compute Nodes 120 a - n , as well as any storage infrastructure. The combination of all uCLoud Platform components in the hosted and extended platforms allows for the operation of a multi-tenant, multi-User, scalable Private cloud.
[0000] FIGS. 22 and 23 illustrate embodiments of systems and methods for creating software defined cloud (SDC) collision domain networks using a tElastic controller 2330 . The tenant administrator accesses the uCloud platform 100 . The tenant administrator accesses the service catalog manager 2305 . The system presents an SDC creation interface 2310 and the tenant administrator launches an SDC service offering 2315 by inputting SDC configuration data 2320 . The tenant administrator inputs the isolated subnets to be used in the SDC. The subnets are also called VLANs or collision domains. The SDC creation request is sent to the tElastic controller 2330 . The tElastic controller 2330 sends out SDC and collision domain network provisioning instructions to all router nodes 2335 , firewall nodes 2340 , and compute nodes 2345 . As a result, a GRE tunnel mesh is created, and within that, a collision domain network is setup for the SDC.
[0083] While this disclosure has described certain embodiments and generally associated methods, alterations and permutations of these embodiments and methods will be apparent to those skilled in the art. Accordingly, the above description of example embodiments does not define or constrain this disclosure. Other changes, substitutions, and alterations are also possible without departing from the spirit and scope of this disclosure, as defined by the following claims. | Method and Apparatus for rapid scalable unified infrastructure system management platform are disclosed by discovery of compute nodes, network components across data centers, both public and private for a user; assessment of type, capability, VLAN, security, virtualization configuration of the discovered unified infrastructure nodes and components; configuration of nodes and components covering add, delete, modify, scale; and rapid roll out of nodes and components across data centers both public and private.. | 7 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to cache synchronization, and more particularly to address broadcast synchronization to a plurality of potentially responding devices.
2. Description of the Relevant Art
Maintaining cache coherency in an N-way system, where N is the number of processors in the system, is essential. In a system where N is small (N<4), the address buses of all cacheable devices may be physically connected together. Therefore, all cacheable devices may see a cache miss address simultaneously. On the other hand, when a system of N is large (N>4), it becomes electrically unfeasible to connect the address buses of all cacheable devices together.
One approach for achieving cache coherency in a system with large N, is by broadcasting the cache miss addresses to all cacheable devices simultaneously, through an address broadcast network. The address broadcast network has an address-in and an address-out connection to each of the cacheable devices. When a device sends a cache miss address to the address broadcast network, the address gets buffered, and then broadcast to all devices concurrently, so that all devices may check or update their tags appropriately.
One problem with building an address network in hardware for large systems (N>4) is that one needs a very large pin count ASIC (Application Specific Integrated Circuit) to accommodate all address-ins and address-outs for all cacheable devices to maintain address synchronization. The expense of building a large pin count ASIC to accommodate all address-ins and all address-outs for all cacheable devices limits this solution to only a very small number of computer systems.
Another possible solution is to slice the address network into X (X>1) slices for a small ASIC solution. The problem with address slicing is that using typical request and grant flow control techniques between address slices to maintain address synchronization requires a computer system performance degradation that is unacceptable.
What is needed is a mechanism for achieving synchronization between address network slices without substantial performance degradation. The request and grant flow control technique used should require a minimum number of control signals passing between each switch.
SUMMARY OF THE INVENTION
The problems outlined above are in large part solved by a system and method providing address broadcast synchronization using multiple switches. Each switch may be an application specific integration circuit (ASIC) or a separate switching device. By dividing address requests between more than one switch, addresses may be broadcast concurrently to a plurality of devices, which may advantageously provide for a higher system performance at a lower cost.
In one embodiment, the system for concurrently providing addresses to a plurality of devices includes a first switch and a second switch. The first switch is coupled to receive address requests from a first plurality of sources. The first switch is configured to output the address request from the first plurality of sources. The second switch is coupled to receive address requests from a second plurality of sources. The second switch is configured to receive the address request from the first plurality of sources from the first switch. The second switch is further configured to delay the address request from the second plurality of sources prior to arbitrating between ones of the address request from the second plurality of sources and ones of the address request from the first party of sources received from the first switch. The second switch selects a selected address request, and the first and the second switch are further configured to broadcast concurrently a corresponding address to the selected address request.
A method is also contemplated, in one embodiment, for concurrently providing addresses to a plurality of devices. In one embodiment, the method comprises receiving at a first switch a first address and a corresponding first request from a first device. The method receives at a second switch a second address and a corresponding second request from a second device, with the first switch being different from the second switch. The method transfers the second address and the corresponding second request to the first switch. The method delays the corresponding first request in the first switch. The method arbitrates in the first switch between the corresponding first request and the corresponding second request but rather the first address or the second address will comprise a first transmission. The method concurrently broadcasts to a plurality of devices the first transmission from the first switch and the first transmission from the second switch where the first transmission from the first switch and the first transmission from the second switch are identical.
In another embodiment, a system for concurrently providing addresses to a plurality of devices includes a first switch and a second switch. The first switch is coupled to receive address requests from a first plurality of sources. The first switch is configured to output the address request from the first plurality of sources. The second switch is coupled to receive address requests from a second plurality of sources. The second switch comprises a broadcast buffer, an incoming buffer, a delay circuit, and a broadcast arbiter. The broadcast buffer is coupled to receive addresses of the address requests from the second plurality of sources. The incoming buffer is coupled to receive addresses of the output of the address requests from the first plurality of sources from the first switch. The delay circuit is coupled to receive the address requests from the second plurality of sources. The delay circuit is configured to delay the address requests from the second plurality of sources for a predetermined length of time. The broadcast arbiter is coupled to arbitrate between ones of the address request from the second plurality of sources and ones of the output of the address request from the first plurality of sources from the first switch for a selected address request. The first switch and the second switch are further configured to broadcast concurrently a corresponding address to the selected address request selected in the broadcast arbiter.
In still another embodiment, a method of arbitrating in a first switch and a second switch between requests to the first switch and the second switch is disclosed. The method comprises tracking which switch was most recently selected and tracking which switch is next to be selected. In response to a reset, the method selects the first switch and indicates that the second switch is next to be selected. In response to only a local request to the first switch or only a remote request to the second switch, the method selects the first switch and indicates that the first switch is next to be selected. In response to only a local request to the second switch or only a remote request to the first switch, the method selects the second switch and indicates that the second switch is next to be selected. In response to both a local request and a remote request concurrently, the method selects the switch which was not most recently selected, and the method indicates that the switch not most recently selected will be the next to be selected. Otherwise, the method selects the first switch and indicates the switch most recently selected as the next to be selected.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the accompanying drawings in which:
FIG. 1 is a block diagram of an embodiment of a computer system including two switches that concurrently provide addresses to a plurality of devices;
FIG. 2 is a block diagram of an embodiment of the two switches shown in FIG. 1; and
FIGS. 3A and 3B are a flowchart of an embodiment of a method for arbitrating in a first switch and a second switch between request to the first switch and the second switch.
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Similar features are designed herein using identical reference numerals. It is noted that the use of a reference numeral with an additional letter may designate a particular one of a group that may referenced as a while with the reference numeral by itself.
FIG. 1 —Computer System Including Two Switches
FIG. 1 is a block diagram of a computer system including two switches, switch 110 A and switch 110 B. As shown, the computer system includes CPUs 115 A- 115 H, input and output devices (I/O) 120 A- 120 D, and memories 125 A- 125 D. Data signals beginning with a P have a processor 115 as a destination, and data signals beginning with an I/O have an I/O device 120 as a destination. Switches 110 A and 110 B are shown receiving input from various groupings of the processors 115 and the I/O devices 120 . The switches 110 A and 110 B are also shown outputting signals to various ones of the processors 115 , the I/O devices 120 , and to the memories 125 .
A plurality of processors (CPUs) 115 A- 115 H (eight as shown), each receives an input, preferably addresses, appropriately referenced as P 0 -P 7 . Each of the processors 115 A- 115 H outputs an output, preferably an address and an address request, such as an address request packet, to one of the two switches 110 A and 110 B. As shown, switch 110 A also accepts address request packets from I/O device 120 A and I/O device 120 B. Also as shown, switch 110 B accepts address request packets from I/O device 120 C and I/O device 120 D. Switch 110 A outputs an output signal, preferably address signals, to the CPUs 115 A- 115 D, the I/O devices I/O 0 -I/O 1 , and memories 125 A- 125 B. Switch 110 B outputs an output signal, preferably address signals, to processors 115 E- 115 H, I/O devices I/O 2 -I/O 3 , and memories 125 C- 125 D. Switch 110 A and switch 110 B also exchange data, preferably including addresses and address requests.
It is noted that while a particular number of processors 115 , I/O devices 120 , and memories 125 are illustrated, any number of processors, I/O devices, and/or memories, or other devices are contemplated. It is also noted that while unidirectional data paths are illustrated, bi-directional data paths may also be used as desired.
FIG. 2 —Address Broadcast Synchronization Switches
FIG. 2 is a block diagram of one embodiment of the switches 110 A and 110 B. As shown, each switch 110 includes a plurality of input FIFOs (First-In, First Out buffers) 205 , a request arbiter 215 , an input multiplexer (MUX) 210 , a broadcast FIFO 225 , an incoming FIFO 230 , a delay circuit 235 , a broadcast arbiter 240 , and an output MUX 245 . The switches 110 exchange output requests from their respective request arbiters 215 and output addresses from their respective input MUXes 210 .
As illustrated, switch 110 A accepts addresses P 0 -P 3 and I/O 0 -I/O 1 , as well as address requests P 0 _req-P 3 _req and I/O 0 _req and I/O 1 _req. Switch 110 A outputs address signals P 0 -P 3 , I/O 0 -I/O 1 , and M 0 -M 1 . Each incoming address P 0 -P 3 and I/O 0 -I/O 1 is received into an input FIFO 205 A- 205 F. The address requests that correspond to the addresses received in the input FIFOs 205 A- 205 F are received at a request arbiter 215 A. In the preferred embodiment, the request arbiter 215 A is a round-robin arbiter, although any other means of arbitration may be used as desired for choosing requests received by request arbiter 215 A. When the request arbiter 215 A chooses (or arbitrates) for a particular address request, the request arbiter 215 A controls the selection at input MUX 210 A with regard to the output of the input FIFOs 205 A- 205 F. The selected address request is output as SW 0 _req to delay circuit 235 A. The output of input MUX 210 A, shown as signal 220 A, is provided to a broadcast FIFO 225 A. It is noted that output signal 220 A is also provided to switch 110 B, and that the address request SW 0 _req is also provided to switch 110 B.
Switch 110 A is also coupled to receive the address request SW 1 _req from switch 110 B, as well as address output signal 220 B. Signal 220 B is received at incoming FIFO 230 A. As shown, broadcast FIFO 225 A and incoming FIFO 230 A each output data to output MUX 245 A, broadcast FIFO 225 A as ‘0’ (zero) and incoming FIFO 230 A as ‘1’ (one). Address request SW 0 _req is delayed for a period of time in delay circuit 235 A before being provided to broadcast arbiter 240 A. The period of time of the delay may be a predetermined period of time. It is noted that in a preferred embodiment, the predetermined period of time is equal to the time required for switch 110 A to receive the address request SW 1 _req and the address output signal 220 B. Broadcast arbiter 240 A chooses (or arbitrates) between request SW 0 _req and request SW 1 _req. The broadcast arbiter 240 A controls the output of output MUX 245 A choosing between ‘0’ and ‘1’. The output of output MUX 245 A, the selected address for the first transmission, is provided concurrently to various groups of the processors 115 , I/O devices 120 , and/or memories 125 through signals P 0 -P 3 , I/O 0 -I/O 1 , and M 0 -M 1 .
As illustrated, switch 110 B accepts addresses P 4 -P 7 and I/O 2 -I/O 3 , as well as address requests P 4 _req-P 7 _req and I/O 2 _req and I/O 3 _req. Switch 110 B outputs address signals P 4 -P 7 , I/O 2 -I/O 3 , and M 2 -M 3 . Each incoming address P 4 -P 7 and I/O 2 -I/O 3 is received into an input FIFO 205 G- 205 L. The address requests that correspond to the addresses received in the input FIFOs 205 G- 205 L are received at a request arbiter 215 B. In the preferred embodiment, the request arbiter 215 B is a round-robin arbiter, although any other means of arbitration may be used as desired for choosing requests received by request arbiter 215 B. When the request arbiter 215 B chooses (or arbitrates) for a particular address request, the request arbiter 215 B controls the selection at input MUX 210 B with regard to the output of the input FIFOs 205 G- 205 L. The selected address request is output as SW 1 _req to delay circuit 235 B. The output of input MUX 210 B, shown as signal 220 B, is provided to a broadcast FIFO 225 B. It is noted that output signal 220 B is also provided to switch 110 A, and that the address request SW 1 _req is also provided to switch 110 A.
Switch 110 B is also coupled to receive the address request SW 0 _req from switch 110 A, as well as address output signal 220 A. Signal 220 A is received at incoming FIFO 230 B. As shown, broadcast FIFO 225 B and incoming FIFO 230 B each output data to output MUX 245 B, broadcast FIFO 225 B as ‘1’ (one) and incoming FIFO 230 B as ‘0’ (zero). Address request SW 1 _req is delayed for a period of time in delay circuit 235 B before being provided to broadcast arbiter 240 B. The period of time of the delay may be a predetermined period of time. It is noted that in a preferred embodiment, the predetermined period of time is equal to the time required for switch 110 B to receive the address request SW 0 _req and the address output signal 220 A. Broadcast arbiter 240 B chooses (or arbitrates) between request SW 0 _req and request SW 1 _req. The broadcast arbiter 240 B controls the output of output MUX 245 B choosing between ‘0’ and ‘1’. The output of output MUX 245 B, the selected address for the first transmission, is provided concurrently to various groups of the processors 115 , I/O devices 120 , and/or memories 125 through signals P 4 -P 7 , I/O 2 -I/O 3 , and M 2 -M 3 .
It is noted that the delay circuits 235 A and 235 B may include any circuit that is configured to delay the output of a received signal. In one embodiment, a delay circuit 235 delays the received signal longer than the minimum time required to propagate the received signal through delay circuit 235 . In another embodiment, delay circuit 235 includes one or more flip-flops. It is also noted that in various embodiments various incoming and outgoing signals to and from switches 110 A and 110 B may be buffered at input to the switch 110 and/or on output from the switch 110 .
Generally speaking, the system of FIG. 1 operates as described herein. The first switch 110 A is coupled to receive address requests from a first plurality of sources. For example, one plurality of sources may be processors 115 A- 115 D and/or I/O devices 120 A- 120 B. The first switch 110 A is configured to output a received address request from the first plurality of sources.
The second switch 110 B is coupled to receive address requests from a second plurality of sources. For example, the second plurality of sources may include processors 115 E- 115 H and/or I/O devices 120 C- 120 D. Switch 110 B is also configured to receive the address request from the first plurality of sources from the first switch 110 A. The second switch is further configured to delay internally address requests from the second plurality of sources. It is noted that the length of the delay may be predetermined, and is preferably equal in length of time to the time delay in receiving the address request from the first plurality of sources from the first switch. The second switch 110 B is further configured to arbitrate between ones of the address requests from the second plurality of sources and ones of the address request from the first plurality of sources output from the first switch. The arbitration between the address requests is to determine a selected address request. Once a selected address request has been selected, the first switch and the second switch are further configured to broadcast concurrently the corresponding address to the selected address request. It is noted that the corresponding address will broadcast to any or all devices, including the CPUs 115 A- 115 H, I/O devices 120 A- 120 B, and memories 125 A- 125 D.
In one embodiment, the second switch 110 B is further configured to output the address request from the second plurality of sources, and the first switch 110 A is further configured to receive this request from the second plurality of sources. First switch 110 A is further configured to delay internally the address request from the first plurality of sources. The time of the delay of the address request from the first plurality of sources may be a predetermined length of time and is preferably a length of time approximately equal to the time required for the second switch 110 B to provide the address request in the second plurality of sources to first switch 110 A. The first switch is further configured to arbitrate between ones of the address request from the first plurality of sources and ones of the address requests from the second plurality of sources from the second switch. The arbitration is to determine the selected address request, as noted above for the second switch 110 B. It is noted that the selected address provided by the first switch 110 A and the selected address provided by the second switch 110 B are the same and are concurrently provided to the devices as described above.
FIGS. 3 A- 3 B—Arbitration by a Broadcast Arbiter
FIGS. 3A and 3B illustrate a flowchart of an embodiment of a method for operating an arbiter, such as broadcast arbiters 240 A and 240 B. The method tracks which switch was most recently selected, and the method also tracks which switch is next to be selected. At decision block 305 , the method checks to see if reset has been asserted. If reset has been asserted in decision box 305 , then an output MUX selects output ‘0’ (i.e. switch 110 A) and the next granted switch will be the other switch (i.e. switch 110 B) (step 310 ).
If reset has not been asserted in decision block 305 , then the method determines if only a local request has been made to the first switch 110 A or only a remote request has been made to the second switch 110 B in decision block 315 . If only a local request has been made to the first switch 110 A or only a remote request is made to the second switch 110 B, then the method selects output MUX output ‘0’ and the next granted switch will be the same switch (step 320 ).
If there has not been only a local request to the first switch 110 A or only a remote request to the second switch 110 B, then the method moves to decision block 325 . If only a local request has been made to the second switch 110 B or only a remote request has been made to the first switch 110 A in decision box 325 , then the method selects output MUX output ‘1’ and the next granted switch will be the same switch (step 330 ).
If only a local request to the second switch 110 B or only a local request to the first switch 110 A has not been made in decision block 325 , then the method moves to decision block 335 . In decision block 335 , if both a local request and a remote request have concurrently been made, and the current granted switch is switch 110 A, then the output MUX selects ‘1’ and the next granted switch is switch 110 A (step 340 ). If in decision block 335 both the local request and remote request have been made concurrently but the current granted switch is not switch 0 , then the method moves to decision block 345 .
In decision block 345 , if both the local request and a remote request have been made concurrently and the current granted switch is switch 110 B, then the output MUX selects ‘0’ and the next granted switch is switch 110 A (step 350 ). It is noted that in decision blocks 335 and 345 , an affirmative decision is made in either case when a local request and a remote request have both been made concurrently. In either case the selected output MUX output is to the switch not most recently selected and the indicated switch as the next granted switch is also the switch not most recently selected.
The default action when all decision blocks are negative, is for the outgoing MUX to select ‘0’, and the next granted switch is the current granted switch (step 355 ).
In various embodiments, the switches 110 A and 110 B may be application specific integrated circuits ASIC 0 and ASIC 1 . In one embodiment, ASIC 0 and ASIC 1 are location strapped via jumpers. It is noted that ASIC 0 preferably will have a pull-up resistor, while ASIC 1 preferably has a pull-down resistor, both of which get latched on reset to identify which is ASIC 0 and which is ASIC 1 . Note that the priority toggles between the broadcast arbiters based on the switch that had the last request granted and the current outstanding request. The method disclosed may advantageously ensure that both arbiters are synchronized to each other without a need for request/grant flow control mechanisms beyond the address and the corresponding address request that was initially received.
As an example of an embodiment of the operations of switches 110 A and 110 B, right after a reset, both processors 115 A and 115 E have an outstanding address packet in the address network. The P 0 address packet is received in switch 110 A's input FIFO 205 A from processor 115 A, whereas the P 4 address packet is received and stored in switch 110 B's input FIFO 205 G from processor 115 E. The request arbiter 215 A in switch 110 A will receive the P 0 request associated with the address stored in input FIFO 205 A. Similarly, request arbiter 215 B receives the P 4 _req address request associated with the P 4 address stored in input FIFO 205 G.
Request arbiter 215 A in switch 110 A controls input MUX 210 A to output the address associated with input signal P 0 as output signal 220 A, which is provided to broadcast FIFO 225 A and to incoming FIFO 230 B. Likewise, request arbiter 215 B controls input MUX 210 B to output the address from P 4 as output signal 220 B. Output signal 220 B is provided to broadcast FIFO 225 B and also to incoming FIFO 230 A. Concurrently with the addresses being routed from the input FIFO 205 to the broadcast FIFOs 225 and incoming FIFOs 230 , switch 110 A has asserted SW 0 _req line indicating the presence of an address from switch 110 A in broadcast FIFO 225 A and incoming FIFO 230 B.
As a finite amount of time is required for the address and the request line to be provided from one switch 110 to the other switch 110 , in this case from switch 110 A to switch 110 B, signal SW 0 _req is first provided to a delay circuit 235 A, before being provided to broadcast arbiter 240 A. In the preferred embodiment, the delay circuit 235 A delays the address request SW 0 _req by approximately an equal amount of time as required for switch 110 A to receive the address and corresponding address request from switch 110 B. In this embodiment, broadcast arbiter 240 A receives notice that an address is present in the broadcast FIFO 225 A concurrently with an address being available in the incoming FIFO 230 A. The broadcast arbiter 240 A chooses (or arbitrates) for priority between the SW 0 _req and SW 1 _req. The preferred arbitration method is described above with respect to FIGS. 3A and 3B. Broadcast arbiter 240 A selects either ‘0’ or ‘1’ denoting the address from switch 110 A or switch 110 B, respectively, in controlling the output of the output multiplexer 245 A.
It is noted that since SW 0 _req and SW 1 _req are both required to cross from one switch to the other, the signals endure a delay, such as two clock cycles in one embodiment. Therefore, each switch 110 A and 110 B delays the address request that it sends, SW 0 _req and SW 1 _req, respectively, to the broadcast arbiter 240 of the other switch by an equivalent time period of 2 clock cycles. This delay ensures that the broadcast arbiters 240 A and 240 B in each switch 110 A and 110 B receive the address request concurrently.
Switch 110 A has the P 0 address placed in its broadcast FIFO 225 A and the P 4 address placed in incoming FIFO 230 A. Switch 110 B has the P 0 address placed in its incoming FIFO 230 B and P 4 packet placed in broadcast FIFO 225 B. At this time broadcast arbiter 240 A has received address request SW 0 _req and address request SW 1 _req, whereas broadcast arbiter 240 B has likewise received address request SW 0 _req and address request SW 1 _req.
The arbitration method described above with respect to FIGS. 3A and 3B illustrates a preferred embodiment of how the broadcast arbiter 245 works for each address request that it receives. After a reset, the last granted switch defaults to switch 110 A, so that switch 110 A broadcast arbiter now has the highest priority. When the broadcast arbiter 240 A has highest priority, then both broadcast arbiter 240 A and broadcast arbiter 240 B will select the ‘0’ of the multiplexer 245 B. It is noted that both broadcast arbiter 240 A and broadcast arbiter 240 B are at decision block 345 of FIG. 3 B. Both a local request and a remote request have been received and the current granted switch is switch 110 B (the default upon a reset), therefore the output MUXes 245 A and 245 B both select ‘0’ and the next granted which will be switch 110 A (step 350 ). Thus, the address from P 0 is provided as output 250 A and output 250 B, concurrently on address lines P 0 -P 7 , I/O 0 -I/O 3 , and M 0 -M 3 .
Continuing, at decision block 325 , as the request is now only the request from switch 1110 B, the output MUXes 245 will select ‘1’ and the next granted will be switch 110 B (step 330 ). It is noted that broadcast arbiter 240 A and broadcast arbiter 240 B, following an arbitration method similar to that disclosed in FIGS. 3A and 3B, make selections between local and remote requests which are identical in all cases. It is also noted the broadcaster arbiter 240 A knows that upon a reset that it will have priority just as broadcast arbiter 240 B knows that after a reset it will not have priority.
Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications. | A system and method providing address broadcast synchronization using multiple switches. The system for concurrently providing addresses to a plurality of devices includes a first switch and a second switch. The first switch is coupled to receive address requests from a first plurality of sources. The first switch is configured to output the address request from the first plurality of sources. The second switch is coupled to receive address requests from a second plurality of sources. The second switch is configured to receive the address request from the first plurality of sources from the first switch. The second switch is further configured to delay the address request from the second plurality of sources prior to arbitrating between ones of the address request from the second plurality of sources and ones of the address request from the first party of sources received from the first switch. The second switch selects a selected address request, and the first and the second switch are further configured to broadcast concurrently a corresponding address to the selected address request. A method is also contemplated for concurrently providing addresses to a plurality of devices. A method of arbitrating in a first switch and a second switch between requests to the first switch and the second switch is disclosed where the arbitrated outcomes in both the first switch and the second switch are identical. | 6 |
[0001] This application is a continuation-in-part (CIP) of U.S. patent application Ser. No. 10/437,305, filed May 14, 2003, which is a divisional of U.S. patent application Ser. No. 09/993,912, filed Nov. 27, 2001, now U.S. Pat. No. 6,582,886.
FIELD OF THE INVENTION
[0002] The present invention relates to an improved solvent for use in the production of flexographic printing plates crosslinked by photopolymerization and methods for reclaiming and recycling the solvent. More specifically, the invention relates to a solvent system using alkyl esters, alone or in combination with co-solvents and/or non-solvents, as washout solvents for the unpolymerized material in the printing plates to develop a relief image and a method for developing printing plates. The polymer-contaminated solvent can then be reclaimed or recycled through centrifugation.
BACKGROUND OF THE INVENTION
[0003] Washout processes for the development of photopolymerizable flexographic printing plates are well known and is described in detail in U.S. Pat. No. 5,240,815 which is incorporated herein by reference. Ordinarily, exposed plates are washed (developed) in a developing solvent that can remove the unpolymerized material while leaving the polymerized (cured) material intact. The solvent typically used in such processes include: (a) chlorohydrocarbons, such as trichloroethylene, perchloroethylene or trichloroethane, alone or in a mixture with a lower alcohol, such as n-butanol; (b) saturated cyclic or acyclic hydrocarbons, such as petroleum ether, hexane, heptane, octane, cyclohexane or methylcyclohexane; (c) aromatic hydrocarbons, such as benzene, toluene or xylene; (d) lower aliphatic ketones, such as acetone, methyl ethyl ketone or methyl isobutyl ketone; and (e) terpene hydrocarbons, such as d-limonene.
[0004] One important disadvantage of the known solvents and the procedures for their use is that the solvents being used as developers may act too slowly, causing swelling of the plates and/or damage to the fine detail in the plate by undercutting and/or pinholing. Moreover, when non-chlorinated solvents are used in the washout process, long drying times may be necessary. Furthermore, many of these solvents have flashpoints of less than 100° F., so that the process can only be operated in special, explosion-protected plants. Many of the prior art solvents are considered Hazardous Air Pollutants (HAPS), and are subject to stringent reporting requirements. When chlorohydrocarbons and other toxic chemicals are used, their toxicity also gives rise to disposal problems and worker safety issues.
[0005] An essential step to any photopolymerizable relief printing process is the development of the printing plate after the image is formed through imagewise exposure of the photopolymerizable plate to light. The image is formed by polymerizing and crosslinking of the photopolymerizable material that is exposed while the unexposed portion remains unpolymerized. Ordinarily, development is accomplished by washing the exposed plate in a solvent which can remove the unpolymerized material while leaving the polymerized (cured) material intact. Since such plates can be formed from a variety of materials, it is necessary to match a specific plate with an appropriate solvent. For example, U.S. Pat. No. 4,323,636, U.S. Pat. No. 4,323,637, U.S. Pat. No. 4,423,135, and U.S. Pat. No. 4,369,246, the disclosures of which are incorporated herein by reference, disclose a variety of photopolymer printing plate compositions based on block copolymers of styrene and butadiene (SBS) or isoprene (SIS). These compositions can be utilized to produce printing plates which can be developed by a number of aliphatic and aromatic solvents, including methyl ethyl ketone, toluene, xylene, d-limonene, carbon tetrachloride, trichloroethane, methyl chloroform, and tetrachloroethylene. These solvents may be used alone or in a mixture with a “non-solvent” (i.e. a substance that cannot dissolve unpolymerized materials), for example, trichloroethane with ethanol. In any case, during the development step, the solvent can be applied in any convenient manner such as by pouring, immersing, spraying, or roller application. Brushing, which aids in the removal of the unpolymerized or uncrosslinked portions of the composition, can also be performed to facilitate the processing of the plate.
[0006] Similarly, UK 1,358,062 discloses photosensitive compositions consisting of a nitrile rubber with an addition of photopolymerizable tri- or tetra-unsaturated ester derived from acrylic or methacrylic acid combined with an addition polymerization initiator activated by actinic radiation. Plates made from this composition can be developed by organic solvents including aliphatic esters such as ethyl acetate, aliphatic ketones such as acetone, methyl ethyl ketone, d-limonene, halogenated organic solvents, such as chloroform, methylene chloride, CFC 113 or blends of such solvents. Brushing or agitation can be used to facilitate the removal of the non-polymerized portion of the composition.
[0007] U.S. Pat. No. 4,177,074 discloses a photosensitive composition containing a high molecular weight butadiene/acrylonitrile copolymer which contains carboxyl groups, a low molecular weight butadiene polymer which may or may not contain carboxyl groups, and an ethylenically unsaturated monomer, combined with a free-radical generating system. This composition is also used as the polymer layer of a flexographic printing plate and requires processing with such organic solvents as methyl ethyl ketone, benzene, toluene, xylene, d-limonene, trichloroethane, trichlorethylene, methyl chloroform, tetrachloroethylene, or solvent/non-solvent mixtures, e.g., tetrachloroethylene and n-butanol. The composition may also be processed with water-soluble organic solvents in an aqueous basic solution, such as sodium hydroxide/isopropyl alcohol/water; sodium carbonate/isopropyl alcohol/water; sodium carbonate/2-butoxyethanol/water; sodium borate/2-butoxyethanol/water; sodium silicate/2-butoxyethanol/water; sodium borate/2-butoxyethanol/water; sodium silicate/2-butoxyethanol/glycerol/water; and sodium carbonate/2-(2-butoxyethoxy)ethanol/water.
[0008] U.S. Pat. No. 4,517,279, the disclosure of which is incorporated herein by reference, discloses a photosensitive composition containing a high molecular weight butadiene acrylonitrile copolymer which contains carboxyl groups, and a high molecular weight butadiene/acrylonitrile copolymer which does not contain carboxyl groups, combined with ethylenically unsaturated monomer and a free radical generating system. That composition, which is also used as the polymer layer of a flexographic printing plate, requires processing by blends of tetrachloroethylene and a non-solvent. The composition may also be processed in mixtures of sodium hydroxide/isopropyl alcohol/water; sodium carbonate/2-butoxyethanol/water; sodium silicate/2-butoxyethanol/water; sodium carbonate/2-butoxyethanol/glycerol/water; and sodium hydroxide/2-(2-butoxyethoxy)ethanol/water.
[0009] As can be seen from the foregoing examples of the prior art, the solvents needed for image development will vary depending on the composition of the polymer layer of the plate. The need for different solvent systems is particularly inconvenient, especially if different photopolymer systems are being processed at the same facility. Furthermore, many of the solvents used to develop the plates are toxic or suspected carcinogens. Thus, there exists a need for solvent systems which can be used with a greater degree of safety. In addition, there exists a need for solvent systems which can be used in a variety of plates. U.S. Pat. No. 4,806,452 and U.S. Pat. No. 4,847,182, the disclosures of which are incorporated herein by reference, disclose solvent developers for flexographic plates containing terpene hydrocarbons such as d-limonene which are effective on a variety of plate types. These terpene hydrocarbon-based developers are also non-toxic. However, they have proven to be hazards in the workplace because of their tendency to spontaneously combust thereby causing fires.
[0010] Therefore, commonly assigned U.S. Pat. No. 6,248,502 solves the drawbacks of terpene by using terpene esters as a substitute developing solvent. Because terpene ester has a higher flash point, the fire risk is greatly decreased. However, terpene esters tends to breakdown through repeated distillation which limits the recyclability of the solvent.
[0011] A big drawback of the prior art developing solvent is the lack of an inexpensive method to reclaim the solvent for subsequent use. Reclamation and recycling of current solvents generally require distillation which is energy and labor intensive.
[0012] The present invention relates to an environmentally friendly developing solvent that offers improvement over the prior art. The solvent comprises alkyl esters which have higher flash points when compared to current solvents. For example, d-limonene (a terpene), terpene ester, and methyl ester have a flash points of 120° F., 141° F., and >250° F., respectively. By having a high flash point, alkyl esters offers superior safety in addition to low toxicity, reduced cost, and biodegradability. Furthermore, compared developing solvents of the prior art including terpene ester, alkyl ester causes less plate swelling. Therefore, more alkyl esters (up to 70% by volume) can be used in the developing solvent resulting in faster removal rate of the non-polymerized portion of the plate. Further, after use as a developing solvent, the alkyl esters can be reclaimed and separated from the polymer inexpensively through centrifugation.
SUMMARY OF THE INVENTION
[0013] The present invention relates to ester based solvents for developing printing plates. These solvents, which comprise alkyl esters, either alone or in the presence of other organic materials (co-solvents and non-solvents), can be used with a variety of polymeric systems. The alkyl esters has the general formula RCOOR′, where R can be any organic moiety, preferably and R′ is an alkyl group, preferably having 1 to 12 carbon atoms. The alkyl esters are natural products with low toxicity and are relatively safe to use compared with other solvent systems. The alkyl esters, it has been discovered, provide a unique combination of reduced cost, improved plate quality, low volatility, improved regulatory compliance, low toxicity, reduced washout time, biodegradability, and ease of reclamation.
[0014] It is, therefore, an object of the present invention to provide methods of reclaiming and recycling the polymer-contaminated solvent (alkyl esters) that was used in the developing process for the preparation of relief plates crosslinked by photopolymerization. The reclaiming process can be continuous or batch. The process comprises transferring the contaminated solvent, from a plate processor or a dirty holding tank, to a centrifuge, and centrifuging the contaminated solvent to remove the polymer. The reclaimed solvent can be transfer directly back to the plate processor or to a clean holding tank.
BRIEF DESCRIPTION OF THE DRAWING
[0015] [0015]FIG. 1 shows an embodiment of the invention where the reclaimed alkyl ester based solvent is associated with a single plate processor.
[0016] [0016]FIG. 2 shows an embodiment where the reclaimed alkyl ester based solvent is associated with multiple plate processors.
[0017] [0017]FIG. 3 shows a bowl disc centrifuge.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The present invention comprises alkyl esters based solvents for use in photopolymer printing plate processing. The alkyl esters, which can be used either alone or in a blended form with co-solvents or non-solvents, can be used to develop a number of different photopolymer printing plates. As used herein, co-solvents are non-alkyl ester compounds that can also dissolve the non-polymerized material; and non-solvents are compounds that cannot dissolve the non-polymerized material. The alkyl esters have the general formula RCOOR′, where R can be any organic moiety, and R′ is an alkyl group, preferably having 1 to 12 carbon atoms. R′ can also be a linear or branched alkyl group. Thus, the preferred alkyl esters for this invention includes, but is not limited to, methyl esters, ethyl esters, propyl esters, butyl esters, pentyl esters, hexyl esters, octyl esters, nonyl esters, decyl esters, undecyl esters, dodecyl esters, and any branched compound thereof including isopropyl esters, isobutyl esters, etc. A wide variety of alkyl esters are suitable for use in the solvents of this invention including, but not limited to, alkyl esters of fatty acids with 8-18 carbons.
[0019] Mixtures of the alkyl esters can also be used and may show synergistic effects when compared with a alkyl ester used alone. When a combination of two or more alkyl esters is used, the resulting blend is often more effective as a solvent than the individual alkyl ester. This blend is referred to herein as a MAE (Mixed Alkyl Ester) solvent.
[0020] Various co-solvents (non-alkyl ester compounds that can also, by themselves, dissolve the non-polymerized material) and non-solvents (compounds that cannot, by themselves, dissolve the non-polymerized material) can also be employed with the alkyl esters and MAE according to the invention. Suitable co-solvents include, but is not limited to, n-butanol, 2-ethoxyethanol, benzyl alcohol, ethanol, methanol, propanol, isopropanol, alpha terpineol, dipropylene glycol methyl ether, 2-butoxyethanol, isopropyl alcohol, and 2-(2-butoxyethoxy) ethanol, cyclopentanol, cyclohexanol, cycloheptanol, substituted cyclopentanol, substituted cyclohexanol, substituted cycloheptanol, cyclopentyl substituted alcohol, cyclohexyl substituted alcohol, and cycloheptyl substituted alcohol.
[0021] The co-solvent should be soluble in the alkyl ester or MAE, should have suitable dissolving properties towards the non-photolysed (non-polymerized) portions of the plate that are to be dissolved, should have low toxicity and acceptable safety profiles, and should be readily disposable. The co-solvents are used to modify the properties of the solvent blend. This includes, for example, the addition of co-solvents to aid in the removal of the top protective cover skin on the flexographic plate. In addition, several of the co-solvents, such as terpene alcohols, in particular alpha terpineol, serve as stabilizers to prevent the separation of the solvent blend, which can occur at reduced temperatures. This stabilizer property of the co-solvent becomes important when isoparaffinic hydrocarbons are used as the non-solvent and benzyl alcohol is used as a co-solvent to remove the outer layer of the photopolymerizable printing plate since the benzyl alcohol may separate from the alkyl esters and paraffinic hydrocarbon mixture. Further, the mixture of esters of fatty alcohols and co-solvent is often more effective as a solvent than the individual alkyl ester by itself.
[0022] The non-solvent should be miscible with the ester(s) of fatty alcohols ester and the co-solvents, should have acceptable toxicity and safety profiles, and should be readily disposable or recyclable. The non-solvent are typically used as a filler to reduce cost, therefore, recyclability of the non-solvent material is highly desirable. Suitable non-solvents include, but is not limited to, petroleum distillates, such as aliphatic petroleum distillates, naphthas, paraffinic solvents, hydrotreated petroleum distillates, mineral oil, mineral spirits, ligroin, decane, octane, hexane and other similar materials. Isoparaffinic solvents are commercially available in a wide range of volatility and corresponding flash points. The developing solvent of the invention can made with a wide range of commercially available isoparaffinic solvents as its non-solvent base. The following table shows volatilities and properties of commercially available isoparaffinic solvents suitable for use with the invention.
TABLE 1 Volatility Flash Point (° F.) 106 129 135 147 196 Initial Boiling Point (° F.) 320 352 350 376 433 50% Dry Point (° F.) 331 360 365 383 460 345 370 386 405 487 Vapor Pressure (mm Hg @ 14 6.2 5.7 5.2 3.1 100 ° F.)
[0023] Parameters such as drying rates, fire risk, workplace air quality and volatile organic compound emissions will also play a role in the selected non-solvent choice.
[0024] In addition, in a commercially acceptable product, odor masking materials or perfumes are often added. Such odor masking materials or perfumes can include terpenes to impart a clean, fresh odor.
[0025] The developing solvent components can be varied but a suitable composition would be about 30-75% by volume of at least one alkyl ester and preferably a mixture of alkyl esters, about 20-60% by volume of a first co-solvent capable of dissolving the top protective cover layer of the flexographic plate, about 5-35% by volume of a second co-solvent. Optionally less than about 2% by volume of a perfume or odor masking material can be added to the solvent; however, it is important that the perfume must not adversely affect the function of the solvent. A non-solvent can also be included in the solvent in an amount up to about 45% by volume. A preferred composition would be about 50-70% by volume of at least one alkyl ester and preferably a mixture of alkyl esters, about 20-50% by volume of a first co-solvent capable of dissolving the top protective cover layer of the flexographic plate, about 10-30% by volume of a second co-solvent. A non-solvent can also be included in the preferred mixture in an amount up to about 20% by volume. The preferred co-solvents are 2-ethylhexanol and cyclohexanol; and the preferred non-solvent is an isoparaffinic hydrocarbon. The following solvents are especially preferred: 1) about 70% methyl hexadecanoate, about 20% 2-ethylhexanol, and about 10% cyclohexanol; 2) about 80% propyl tetradecanoate and about 20% dodecanol; 3) about 75% isopropyl hexadecanoate and about 25% benzyl alcohol; 4) about 80% ispropyl tetradecanoate and about 20% cyclohexylethanol; and 5) about 75% ethyl hexadecanoate and about 25% dodecanol.
[0026] The alkyl ester-based solvents may be substituted for the synthetic hydrocarbon, oxygenated solvents or halogenated hydrocarbon solvents used for processing photopolymer printing plates. For example, the alkyl ester solvents are suitable in the processing of photopolymer printing plates based on block copolymers of styrene and butadiene (SBS) or styrene and isoprene (SIS), copolymers of butadiene and acrylonitrile, terpolymers of butadiene, acrylonitrile and acrylic acid and other similar photopolymers. The alkyl ester-based solvents can be applied to the plates by any conventional application means including spraying, brushing, rolling, dipping (immersing) or any combination thereof. The alkyl ester solvents also produce photopolymer plates with less cured polymer image swelling than those processed in conventional hydrocarbon or chlorinated hydrocarbon solvents. Since swelling tends to distort the image formed, this surprising result permits clear, sharp images to be formed at much lower exposure times than those resulting from the use of conventional solvents. Additionally, the solvents of the invention have fairly low volatility which reduces worker exposure during plate processing. Furthermore, because alkyl esters are natural products, they are much less toxic and are more readily biodegradable than synthetic hydrocarbon or chlorinated hydrocarbon solvents.
[0027] After utilization as a developing solvent, the alkyl ester based solvent is contaminated with polymers released from the printing plate. Because the solvent is relatively expensive, it is desirous to be able to recycle the solvent for subsequent developing processes. Applicant has discovered that the present alkyl ester based solvent can be separated from the polymer contaminate simply through centrifugation. The reclaimed solvent has a purity of about 99.5%.
[0028] The reclamation process is described in FIGS. 1 and 2. FIG. 1 discloses the reclamation process with a single plate processor set up. The polymer-contaminated solvent from the plate processor 22 is fed into the centrifuge 20 , preferably through a conduit. Typically, the polymer-contaminated solvent contains about 3% to about 10% polymer, most preferably about 6% polymer. Because the process yield is generally less than 100%, fresh solvent is also fed into the centrifuge from a replenishment drum 24 .
[0029] The centrifuged 20 used is preferably, but not limited to, a bowl disc centrifuge shown in FIG. 3. Polymer-contaminated solvent to be purified is fed to the feed port 30 of the centrifuge, from which it flows down the central feed tube 40 and out into the bowl at the bottom of the disc stack 38 . While contaminated solvent is fed to the centrifuge at the feed port 30 , the moveable piston 32 is in the up or closed position, as controlled by the flow of the centrifuge operating fluid (usually water), which is delivered to the centrifuge by the action of a solenoid valve 36 . The solvent flows through the discs 38 , which retain polymers more dense than the solvent. The polymer travels to the periphery of the discs and are accelerated to the outermost part of the bowl, where they are collected. The purified solvent transits the disc stack and exits the centrifuge as the clarified product at the exit 42 . Periodically, solids are ejected from the centrifuge bowl by briefly opening the moveable piston 32 by means of the operating fluid. The polymer waste stream is ejected from the bowl through the waste port 26 . Typically, the centrifuge bowl is open for about 3 second at a time for ejecting the polymer waste from the bowl. During each opening, about 0.017 pounds of solvent is lost per square foot of photopolymer plate processed. The waste is held in a waste holding tank 32 to be prepared for disposal. For safety purposes, the centrifuge may have a pressure relief valve 34 attached to an exhaust fan 36 for venting if excessive pressure is present in the system.
[0030] The purified solvent can be fed directly to the plate processor 22 as depicted in FIG. 1 or to a clean holding tank 28 to be prepared for subsequent use. In an embodiment of the invention, the polymer-contaminated solvent is transferred from the plate processors to a dirty holding tank 30 before being fed into the centrifuge. Likewise, the purified solvent exiting the centrifuge is transferred to a clean tank before the solvent is distributed to individual plate processor. The process of FIG. 2 is more flexible than that of FIG. 1 in that the number of operating plate processor can be varied according to the needs and requirements of the overall developing process.
[0031] The centrifuge may be any type of centrifuge, preferably a disc centrifuge provided with conical discs and able to centrifuge liquids at high g forces as described above. Depending on the characteristics and throughput of the solvent being processed and the size of the centrifuge bowl, the desludger centrifuge rotational speed should be adjusted so as to provide a centrifugal force of at least about 4,000 g, and preferably between about 4,000 g and 12,000 g. Since the g force is a function of the rotational speed and the radius of the centrifuge bowl, the optimum process g force is limited only by the size of the equipment used and the strength of the stainless steel or other alloy used in the fabrication of the equipment.
[0032] The solvent is preferably maintained at room temperature throughout the process. Most preferably, the solvent is maintained at about 70° F. This can be accomplished through cooling and/or heating of the solvent in the piping system and/or the centrifuge. On the other hand, depending on the particular solvent composition, no heating and/or cooling is required as room temperature is sufficient to maintain the solvent temperature in the operating range.
[0033] The invention has been disclosed broadly and illustrated in reference to representative embodiments described above. Those skilled in the art will recognize that various modifications can be made to the present invention without departing from the spirit and scope thereof. | The present invention provides methods of reclaiming and recycling the polymer-contaminated solvent that was used in the developing process for the preparation of relief plates crosslinked by photopolymerization. The solvent of the present system contains alkyl esters, alone or in combination with co-solvents and/or non-solvents, as washout solvents for the unpolymerized material in the printing plates to develop a relief image and a method for developing printing plates. The process comprises transferring the contaminated solvent, from a plate processor or a dirty holding tank, to a centrifuge, and centrifuging the contaminated solvent to remove the polymer. The reclaimed solvent can be transfer directly back to the plate processor or to a clean holding tank. | 6 |
This application is a 371 of PCT/GB95/02707 and claims priority to GB 9423332.7.
BACKGROUND OF THE INVENTION
The present invention relates to a method of preparation of chemical compounds and, in particular, to a method of preparing combinatorial libraries of chemical compounds. The method is especially suitable for the preparation of natural and synthetic chemical compounds which are to be tested for activity as therapeutic agents, though it need not be used exclusively for this purpose. In addition to being used for the preparation of combinatorial libraries, the method of the present invention also facilitates easy identification of individual compounds, so that any compounds which show encouraging biological activity can be prepared on a larger scale for further analysis. By modifying the method of the present invention, it is possible to prepare individual compounds in pure form in a non-combinatorial format.
The synthesis and screening of combinatorial libraries is becoming increasingly important in the pharmaceutical industry as a means of drug "discovery". The major advantages of combinatorial chemistry are that it is faster and cheaper than orthodox methods. This makes it a much more effective technique in the quest to uncover new therapeutic agents, particularly in circumstances where there is little or no information available concerning the types of structures likely to show the desired activity.
The wider availability of solid-phase synthetic methods has also led to increased interest in combinatorial chemistry. Clearly, solution chemistry is unsuitable for a technique which aims to produce a multiplicity of new products together, since this does not allow physical separation between the different materials produced. The products are therefore likely be contaminated with excess reagents, by-products etc, leading to difficulties in separation and purification.
The preparation of combinatorial compound libraries typically involves a number of successive stages, each of which involves a chemical or enzymatic modification of an existing molecule. Most typically, this process involves the addition of a monomeric unit or other synthon to a growing sequence, or the modification of chemical functionality on the sequence. Conveniently, the sequence or growing chain of interest is attached to a solid support. By carrying out the desired series of synthetic steps on the bound starting material, and by altering the nature of the monomeric or other synthon units, the type of chemistry and the sequence of reactions, it is possible to prepare an enormous number of individual compounds in short time.
As indicated above, combinatorial methods entail a series of chemical steps with multiple choices of chemical reagents for each step. The complexity of the combinatorial library thus produced is determined by the product of the number of reagent choices for each step of the synthesis, which can be quite large. The problem which then arises is identification and characterisation of members of the library which display particular desired properties.
Various solutions have been proposed to deal with this: For example, members of the library can be synthesised in spatially segregated arrays. However, because of the extra burden which maintenance of segregation imposes, this approach tends to lead to relatively small libraries. Alternatively, in the so-called "multivalent synthesis" method, a library of moderate complexity is produced by pooling multiple choices of reagents during synthesis. If a pool is shown to have properties of interest, it is re-synthesised with progressively lower complexity until a single compound or class of compounds is identified having the desired property. The ultimate size of a library produced by this technique is inevitably restricted because of concentration effects which determine the limits of detection at which activity can be discerned.
The so-called "mix and split synthesis" method relies on combinatorial synthesis carried out on discrete solid particles such as minute resin beads. Through a protocol of mixing and separating beads at the end of each step in the synthetic sequence, populations of beads are generated to which are bound the products of specific reaction sequences. Inevitably, individual beads obtained from the final reaction step have different products attached, so that identification and characterisation of active materials is still a problem.
Fortunately, biologically active compounds show remarkable potency and receptor sites are highly selective, so it is possible to detect low concentrations of active compound amid an extensive background of inactive material using standard in vitro screening techniques.
Another drawback of the mix and split synthesis method is that some measure of over-representation and omission of individual compounds is inevitable because of the randomness introduced by the mixing and splitting steps.
To counteract the above problems of identification and characterisation, some workers have proposed co-synthesis of a sequencable tag which encodes the series of steps and reagents used during synthesis of respective constituents of the library. More recently, it has been proposed to use tagging molecules to encode both the step number and the chemical reagent used in a given step, as a binary record of the synthetic steps experienced by each bead. This technique undoubtedly adds to the complexity of operations carried out during development of a combinatorial library.
From the foregoing, it is apparent that known methods of preparing combinatorial libraries of chemical compounds suffer from two major drawbacks: Either the materials are prepared by maintaining segregation, with the inevitable consequence that only relatively small libraries are practicable, or the materials are prepared without segregation but in such minute quantities that characterisation is rendered very difficult.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a method of making a library of chemical compounds which allows wide diversification in the products obtained without over-representation and/or omission, at the same time as providing a clear indication of the sequence of steps which has been followed to synthesise a particular compound, thereby facilitating characterisation of individual materials.
In a first aspect, the invention is a method of making a library of compounds, which method comprises the following steps:
(a) individually marking with indicia a plurality of discrete reaction zones defined on laminar solid support material;
(b) charging each of said reaction zones with a starting material;
(c) sub-dividing the reaction zones into at least two initial batches;
(d) applying at least two different reagents, one to each of the reaction zones in each initial batch, and recording the identity of those reaction zones to which each of said different reagents is applied;
(e) subjecting all reaction zones to reaction conditions which promote reaction to completion;
(f) further sub-dividing the reaction zones into at least two alternative batches;
(g) applying at least two different reagents, one to each of the reaction zones in each alternative batch, and recording the identity of those reaction zones to which each of said different reagents is applied;
(h) subjecting all reaction zones to reaction conditions which promote reaction to completion, and
(i) repeating steps (f) to (h) inclusive from zero to n times, as desired.
It will be understood that n may be any whole number integer, the value of which depends on the complexity of the combinatorial library that it is intended to produce.
The method outlined above provides the synthetic chemist for the first time with the means to synthesise any number of single, easily identifiable labelled chemical compounds on a controllable pre-defined scale of preparation. In particular, this invention offers considerable handling advantages over prior art methods. For example, if desired the entire set of individual reaction zones may be handled as a single laminar medium. This opportunity does not exist with free-flowing microscopic resin beads. The method of division does not rely on the laminar support material being a particular shape. Thus, it is possible for the support to be in the form of tapes or streamers.
In an especially preferred form, the reaction zones are defined on sheets of material. An individual sheet may represent a single reaction zone, in which case a plurality of sheets is required to put the invention into effect. Alternatively, a single sheet may be sub-divided into an array of reaction zones of equal size, individual elements of the array being separable from each other for effecting step (c) above. In one possible variant of this method, each sheet is charged with a different starting material in step (b).
An especially preferred form of sheet material is paper, particularly paper which has been treated to enable the starting material to bind to the sheet. When the starting materials are amino acids or peptide fragments, the paper may for example carry allylic anchor groups to releasably bind the carboxylic acid groups of amino acids to the paper; a variety of other linking groups is also possible. The first and subsequent reagents may attach further amino acids or peptide fragments to the already bound amino acid residues on the sheet in known manner.
Another type of paper which may be used has free amino groups which may releasably bind to carboxy groups of amino acids forming the starting material of the library compounds. One method of making such a paper is to treat cellulose, preferably in powder form, with acrylonitrile and a base, generally under aqueous conditions, to form a cyanoethyl ether of cellulose. The product may be dried and reduced, for example with borane in tetrahydrofuran, to aminopropyl cellulose. After removal of residual reagents the amino groups may be protected, for example by conversion of the aminopropyl groups to tert-butyloxycarbonyl aminopropyl groups and the resulting substituted cellulose may be mixed with cellulose fibre and formed into paper by standard paper-making methods.
The tert-butyloxycarbonyl or "Boc" groups may then be removed to provide the required paper with free amino groups.
In a second aspect, the invention is a method of preparing a paper support material for use in the synthesis of chemical compound libraries, which method comprises:
(a) linking cellulose with a compound which is selected from the set consisting of an amine precursor or a compound having a protected amine group;
(b) in the case of an amine precursor, generating the free amine and then protecting it with a conventional amino protecting group;
(c) incorporating the amine-functionalised cellulose into a paper sheet by mixing with paper fibre and forming into sheets, and
(d) reacting the paper sheets obtained from step (c) above with an amino deprotecting reagent to provide free amine groups on the paper sheets.
Alternatively, materials other than paper may be used for making the sheets. This is an important consideration for those branches of chemistry which require a non-protic environment, since paper is a protic material.
One possible alternative is a polyethylene or polypropylene film which has been grafted with polystyrene chains, as described in published PCT Patent Application No. WO 90/02749. Alternatively, the sheet may be of a laminated construction, being in the form of a solid material trapped between two or more layers of porous mesh. One laminate of this type consists of a so-called "resin cloth" comprising cross-linked polystyrene resin containing amino groups formed as a layer sandwiched between fibrous sheets, for example, non-woven polypropylene sheets, on which indicia may be borne. The use of other materials is, of course, possible.
A non-protic sandwich material such as that described above permits a wider range of chemistries to be carried out. For example, chemistry is permitted to be performed on a supported resin cloth which usually requires strictly anhydrous conditions. Example reactions include, but are not limited to, use of a strong non-protic base to generate anions of chemical substrates affixed to the resin cloth. Further manipulations of these anions permits, for example, Heck type couplings, Stille couplings, heteroaryl couplings, carbonylations, carboxylations and carbamoylations not normally permitted in a protic environment.
In a third aspect, the invention is a method of preparing a laminar resin support material for use in the synthesis of chemical compound libraries, which method comprises affixing a layer of particulate functionalised solid support resin material to a porous inert laminar material.
Preferably, the layer of particulate functionalised solid support resin material is sandwiched between two layers of porous inert laminar material.
In general, suitable sheet material may be any material which is readily markable with indelible indicia, is divisible in equal proportions, allows the sheets to be formed into a stack and subsequently separated and to which the constituents of the compounds of the library may releasably be bound. The sheet and method of binding the compounds are preferably such that known amounts of the compound may be repeatably released from a single sheet portion bearing the compound.
It should be noted that the present invention is not limited to the preparation of biologically active compounds. It is applicable to any organic or inorganic species which, used in combination with other reagents, will form oligomers bound to the solid sheet. The compounds which are stored in the library must however be compatible with the material of the sheet.
Besides sheet materials, any suitable support material can be adapted for use in the method of the present invention provided that it has the capacity for division and subsequent sub-division into discrete reaction zones and provided that it possesses the necessary surface active qualities to serve as a vehicle for the intended reaction steps.
The compounds prepared in the library may be linked to the support by a wide variety of methods, depending on the nature of the support and the compounds to be prepared. Apart from the allylic anchoring group/amino acid system mentioned above, chemical linkers which may be cleaved by acidic, basic, hydrogenolytic or other chemical reagents may be used, as may light-induced cleavage. Combinations of these methods may also be used.
The amount of compound stored in each reaction zone may vary according to the nature of the compound and the nature of the support material, and also according to the size of the zones. Amounts of compound varying from a few nanograms to several milligrams may be stored on portions of paper sheet of convenient size. In principle any amount of compound may be stored provided that the support material is large enough.
Typically, the different reagents used in the method according to the present invention are individual monomeric units and may be chosen from a large variety of compounds.
These include agents such as amino acids, nucleotides, sugars, naturally-occurring and synthetic heterocycles, lipids, and combinations thereof, though it will be understood that this list is not exhaustive. In general, any bifunctional group may be used which may be linked to the support material or to the growing sequence in protected form, and subsequently deprotected and reacted with a further group. Alternatively, a monofunctional group may be used to complete the sequence.
It is an essential feature of the present invention that individual reaction zones are identified, that is to say, labelled with some form of indicia which uniquely characterises each reaction zone. The indicia may comprise, for example, numbers, letters, symbols or colours in a coded combination. The indicia may be applied to the respective reaction zones before synthesis commences using known printing methods. These are preferably such that the ink used will not leach out of the reaction zones during the synthetic procedures, or otherwise interfere with formation and subsequent removal of a compound held on a particular reaction zone. U.V.-sensitive ink which is "fixed" to the reaction zones by exposure to ultraviolet radiation after printing is generally suitable for this purpose. Other types of indicia, not necessarily optical in nature, may be used for identifying individual reaction zones. Possible alternatives include Smiles strings, bar-codes, chemical structures, marked or printed punched card formats, ultraviolet-readable fluorescent systems and electro-magnetically readable devices such as magnetic strips. The type of indicia used may depend on the size and shape of the support material and/or reaction zones.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1. FIG. 1 shows a schematic of one form of the support material.
DETAILED DESCRIPTION OF THE INVENTION
The invention will now be described by way of example only with reference to the drawing (FIG. 1) which shows in schematic form one particular embodiment of support material used in performance of the present invention and a convenient pattern of sub-division.
Referring now to FIG. 1, the illustrated arrangement shows orthogonal arrays of reaction zones 3 defined on a series of support sheets 1. The reaction zones are arranged in a grid or matrix layout in straight rows along one dimension and straight columns along the other dimension, each reaction zone being provided with a unique tag or label.
In the next step, each of the sheets 1 is treated with a different first reagent which becomes bound to the sheet to form the first monomer or constituent serving as the starting material for subsequent steps. The sheets are then superposed to form a block in which corresponding reaction zones 3 of respective sheets are aligned with each other. The block of sheets so formed is then divided by making a first series of cuts through the stack, e.g. in the X direction, thereby forming a plurality of stacked strips 2.
Each stack of strips 2 is then treated with a reagent to effect deprotection or activation of the first constituent following reaction with a different second reagent to effect binding of a respective second constituent to the first constituents already bound on the strips.
Following this, the treated stacks of strips are reassembled to reform the block and a second series of cuts is made at right angles (in the Y direction) to the first so that each strip becomes further sub-divided into smaller elements corresponding to the reaction zones (3).
Each of the stacks of individual reaction zones is then deprotected if necessary and treated with a different third reagent to effect binding of a respective third constituent on the free end of the second constituent already in place.
If, in this example, a total of twenty sheets is used initially and if each sheet is treated with a different first reagent monomeric unit, twenty different sheets having attached a first monomer or fragment will be formed. When the superposed sheets are divided to form, say, 20 strips and each strip is treated with a different reagent a total of 20×20=400 dimeric chains is formed, each having a different combination of first and second monomers or fragments. Subsequent reassembly of the block and further sub-division along the second dimension into, say, 20 slices and treatment of each of the slices with different reagents will give 20×20×20=8,000 different pure trimeric structures. The total number of monomers, dimers and trimers may be increased by dividing the block into a greater number of strips or slices, or by increasing the number of sheets. Thus, if 50 sheets are used, divided into 50 strips and 50 slices, the number of different pure individual trimeric structures will be 125,000.
Each of the trimers will be different and will be identifiable unambiguously from the indicia (which may be letters and/or numbers applied by printing) marked on the reaction zones.
At this final stage of the process, the sheets have been cut in a fashion to provide individual pieces of paper, each of which is marked with a single, unique index, which is in itself an identifier of the single, unique chemical structure attached to that portion of paper. Furthermore, all possible combinations are formed of compounds available from the constituents provided by the reagents used.
In the embodiment of the invention described above, the reaction zones may be square or oblong and arranged in an orthogonal pattern. However, other geometrical arrangements may be used. In principle the sheet portions may be of any shape and arranged in any type of grid pattern, subject only to the need to divide the sheet into individual portions.
The sheet material may be, but is not limited to, paper and depending on the size of the sheets cutting may be carried out using any suitable cutting device, such as scissors or an ordinary office guillotine. The arrangement described above allows a very large number of different dimeric and trimeric and larger polymeric structures to be assembled easily and rapidly.
It will be apparent that in a library of single individual compounds, each of which is identified by means of its own unique indicia, an individual sheet portion may be easily identified. Thus, evaluation of the biological or other activity of the compound cleaved from such an identified sheet portion will permit, by means of targeted screening of structurally related compounds, a search for activity by substructure within a library generated by a combinatorial method.
The method of making a library of compounds described above may be considered as starting with a three-dimensional stack of sheets which is divided three times in different dimensions (once by separating the sheets, and twice by cutting) and treating with three different sets of reagents. The same principle may be applied to a two-dimensional system using a single sheet which is divided twice in two transverse directions and treated with two reagents.
Such an arrangement still allows provision of a large number of compounds in a library. For example, if a single sheet is divided into a pattern consisting of 50×50 squares a total of 2500 different compounds, each of known composition and unambiguously identified, may be obtained. In another embodiment, the sheets may be in the form of tape or streamers which comprise only a single line of reaction zones which are separated by cutting in the transverse direction. These tapes or streamers bearing a one-dimensional array of reaction zones may be superposed to form a block which is treated and subdivided in a manner similar to that described above.
It will also be appreciated that the block of sets of individual reaction zones may be further divided and reacted with a fourth or subsequent set of reagents to provide a further dimension of product variation.
In general, the invention is applicable to any arrangement of sheet material in which both the "sheets" and the reaction zones defined thereon may, after sub-division, be handled and subjected to the desired chemical process steps without losing their physical integrity or their identifying indicia. The manner in which the sheets are divided into portions (cutting, stamping, tearing etc.) will depend on the identity of the sheet material and the shape and size of the reaction zones.
The invention is further illustrated by the non-limiting examples described below, in which the following abbreviations are used:
Fmoc: 9-Fluorenylmethoxycarbonyl
Boc: Tert-butyloxycarbonyl
THF: tetrahydrofuran
DMF: N,N-dimethylformamide
TFA: trifluoroacetic acid
HOBt: N-1-hydroxybenztriazole
TBTU: 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate
Hunig's base: N,N-diisopropylethylamine
EXAMPLE 1
Syntheses conducted on Boc-aminopropyl cellulose sheet
Preparation of cyanoethyl cellulose:
A suspension of 70% water wet-partially cross-linked cellulose powder (XEC Whatman) 13 kg was suspended in dioxan (28 l), and treated with a solution of sodium hydroxide (210 g) in water (200 ml) and the viscous suspension stirred at room temperature for 10 min. Acrylonitrile (201.5 g, 250 ml, 3.79 mole) was added, the mixture stirred 5 min, further acrylonitrile (201.5 g, 250 ml, 3.79 mole) was added, the mixture stirred 5 min, and thereupon a final portion of acrylonitrile (403 g, 500 ml, 7.95 mole) was added and the whole reaction mixture stirred at room temperature for a total of 5 hr. There was no detectable exotherm under these conditions.
The bulk material was recovered by filtration, and the crude product washed with water until the washings were of pH 7. The water was then removed by suction, the filter cake dried by suspension in acetone (2×10 l), collected by filtration, further washed with acetone (2×10 l), and finally dried at 80° C. for a total of 72 hr. A total of 3.78 kg anhydrous material was obtained. Elemental analysis of the recovered solid shows there to be N present in the expected ratio.
CHN analysis: Found % C: 46.60; H, 6.60; N, 2.16. C: 46.52; H, 6.54; N, 2.13.
This experiment was repeated three times on approximately the same scale to provide a total of 11.9 kg of dried sample of the cyanoethyl ether of cellulose.
Reduction of cyanoethyl cellulose to aminopropyl cellulose:
A dry sample of cyanoethyl cellulose powder as above was purged under dry nitrogen, treated cautiously with a solution of borane/tetrahydrofuran complex (1M) in THF (14 l), stirred for 1 hr at room temperature, and then cautiously warmed to gentle reflux for a total of 24 hr. The cooled solution was very cautiously treated aqueous ethanol (10%, 1 l) with external ice-water cooling, and some evolution of hydrogen was detected. The wet slurry was then filtered and the wet filter cake slurried in HCl (1M, 12 l) for a total of 30 min, recovered by filtration, and re-suspended in (1M, 12 l) for a total of 1 hr. The product was collected by filtration, washed extensively with water until the washings were of pH 7, and then sucked dry. This filter cake was then slurried in ethanol (10 l), collected by filtration and sucked dry for a total of 1 hr. This cake was then slurried with ether (10 l), the product collected by filtration, sucked dry overnight at room temperature and was finally dried at 50° C. to constant weight.
Analysis of the free amine content by standard methods revealed an amine content of 0.50 mmole/g dry weight.
This experiment was also repeated for a total of three times to provide a total of 13.24 kg of dry powder.
Protection of the amino group to give Boc-aminopropyl cellulose:
A solution of sodium carbonate (1.26 kg) in water (1 l) was diluted with THF (12. l) and a sample of aminopropyl cellulose hydrochloride (4 kg) was added cautiously to avoid frothing. This was treated with di-tert butyl pyrocarbonate (4 kg) and the mixture was allowed to stand at room temperature for one week. The solid material was collected by vacuum filtration, washed with water until the washings were of pH 7, then slurried in acetone (10 l), and collected by filtration. This slurry treatment of the collected solid was then repeated (10 l). The product was finally collected by filtration, sucked to dryness and dried overnight at 80° C. under vacuum. This gave a colourless solid 4.2 kg.
This experiment was then repeated three times to provide a total weight of the N-protected derivative of 13.06 kg. This showed a residual moisture content of approximately 15%, which could have been removed by extremely vigorous drying. However, such removal was unnecessary for the next step in the procedure.
Preparation of bulk scale Boc-aminopropyl cellulose paper sheet:
Blank paper fibre in the form of long staple raw cellulose (27.8 kg) was slurried in a large volume of water (2600 liters) for a total of 20 min. This slurry was combined with the sample of powdered Boc-aminopropyl cellulose (13.06 kg) and further slurried for a total of 10 min to achieve adequate dispersion. A polyamide epichlorohydrin cross-linking agent (1.14 l) was added, and the paper slurry was then prepared in sheet form by conventional means. This produced a finished roll of paper of approximately 28 kg in weight.
Deprotection of the Boc-aminopropyl cellulose sheet:
A sample of the Boc-aminopropyl cellulose sheet of A4 size was suspended in a solution of trifluoroacetic acid in solution of dichloromethane (50%, 30 ml), for a total of 30 min. The paper was then washed with dimethylformamide (DMF) to remove excess TFA, with methanol (×1), neutralized (1M NaOH), washed water, methanol and then dichloromethane and finally dried at 40° C. under vacuum for a total of 1 hr.
This paper was assayed for free amine content by a known method using picric acid, which showed a reproducible free amine level in the range of 2-3 nmoles/mm 2 .
Preparation of Lys-Tyr-Lys and Thr-Tyr-Ser on amine-functionalised paper:
Fmoc-O-t-butyl-Ser Derivatisation:
A sample of the above described amine functionalised paper (two sheets of dimensions 210×197 mm, of 2.85 nmoles/mm 2 , or 0.18 mmole total amine content) indelibly marked with indicia was derivatised by reaction with 2,4-dichlorophenyl-4-(N-α-Fmoc-O-tert-butyl-Serinyloxymethyl) phenoxyacetate (650 mg or 2.7 times excess) in DMF solution for a period of 17 hr at room temperature following the general method given by Bernatowicz et al. (Tetrahedron Letters 1989, 30: 4341). The paper was washed with DMF to remove reagents (×3), dichloromethane (×6) and was then dried at room temperature under vacuum.
Determination of free amine content indicated that the degree of coupling in this reaction was of the order of 85%.
Residual amine groups were acetylated using a solution of acetic anhydride (4 ml), collidine (6 ml) and 4-dimethylaminopyridine (2 g) in acetonitrile (20 ml) for 1 hr at room temperature. The paper was then washed with acetonitrile (×3), dichloromethane (×6), and dried under vacuum.
Deprotection of the Fmoc group was achieved using a standard method utilising a solution of piperidine (15 ml) in dichloromethane (5 ml) for 30 min at room temperature. Washing of the paper with DMF (×2) and dichloromethane (×6), followed by drying under vacuum gave the material ready for the next coupling.
α-Fmoc-ω-Boc-Lys Derivatisation:
A sample of the same amine derivatised paper of identical dimensions indelibly identified with indicia was derivatised in an identical fashion using instead the analogous derivative of α-Fmoc-ω-Boc-Lys.
Residual amine acetylation and deprotection prior to the further functionalisation were performed in a manner identical to that described above.
Coupling of the second monomer (Fmoc-O-t-butyl-Tyr):
The two above monomerically linked pieces of paper were placed in one vessel and treated with a five-fold excess of a solution of the HOBt ester of Fmoc-Tyr-O-t-butyl ether which was prepared by pre-activation of a solution of Fmoc-O-t-butyl-Tyr (3.47 g, 7.56 mmol), HOBt (1.02 g, 7.56 mmol), TBTU (2.42 g, 7.56 mmol) and Hunig's Base (2.64 ml, 15.12 mmol) in DMF (160 ml) for a period of 30 min. This preformed ester solution was then reacted at room temperature overnight with the paper samples. The pieces of paper were then washed with DMF (×3) to remove reagents, dichloromethane (×6), and dried under vacuum.
Residual amine groups were acetylated using a solution of acetic anhydride (4 ml), collidine (6 ml) and 4-dimethylaminopyridine (2 g) in acetonitrile (20 ml) for 1 hr at room temperature. The paper was then washed with acetonitrile (×3), dichloromethane (×6), and dried under vacuum.
Deprotection of the Fmoc group was achieved using a standard method utilising a solution of piperidine (15 ml) in DMF (15 ml) per sheet for 30 min at room temperature. Washing of the paper with DMF (×4) and dichloromethane (×6), followed by drying of the paper under vacuum gave the material ready for the next coupling.
Coupling of the third monomer:
The sample of paper bearing Tyr-Ser was further reacted separately with a sample of the HOBt ester of Fmoc-Thr-O-t-butyl ether prepared by pre-activation of a solution of Fmoc-Thr-O-t-butyl ether (1.5 g, 3.78 mmol), HOBt (0.51 g, 3.78 mmol), TBTU (1.21 g, 3.78 mmol) and Hunig's Base (1.31 ml, 7.56 mmol) in DMF (85 ml) for a period of 30 min. The paper was reacted at room temperature overnight.
The sample of paper bearing Tyr-Lys was further reacted separately with a sample of the HOBt ester of α-Fmoc-Boc-Lys prepared by pre-activation of a solution of α-Fmoc-Boc-Lys (1.77 g, 3.78 mmol), HOBt (0.51 g, 3.78 mmol), TBTU (1.21 g, 3.78 mmol) and Hunig's Base (1.31 ml, 7.56 mmol) in DMF (85 ml) for a period of 30 min. The paper was reacted at room temperature overnight with this preformed solution.
The two pieces of paper were then washed with DMF (×2) to remove reagent, dichloromethane (×3), and dried under vacuum. Residual amine groups were acetylated using a solution of acetic anhydride (4 ml), collidine (6 ml) and 4-dimethylaminopyridine (2 g) in acetonitrile (20 ml) per sheet for 1 hr at room temperature. The paper was then washed with acetonitrile (×4), dichloromethane (×4), and dried under vacuum.
Final deprotection of the Fmoc group was achieved using a standard method utilising a solution of piperidine (15 ml) in DMF (15 ml) per sheet for 30 min at room temperature. Washing of the paper with DMF (×4) and dichloromethane (×6) followed by drying of the paper under vacuum gave the material ready for the final cleavage.
Cleavage of the trimers from the paper:
The sample of paper bearing Thr-Tyr-Ser was cut into small portions, treated with TFA/H 2 O (95:5, 89.25 ml) and stored at room temperature overnight. Solid material was removed by filtration and washed with dichloromethane (×2) and methanol (×2), and the filtrates combined. Acid was removed by evaporation below 40° C., and the sample freed from acid by azeotropy from toluene/dichloromethane (×2). The sample was dissolved in water (15 ml), filtered, and freeze dried. The mass recovery was essentially quantitative. This was examined by hplc analysis and the desired material was shown to be the major product by comparison with a genuine sample, and moreover exhibited identical m/e peaks in the mass spectrum.
The sample of paper bearing Lys-Tyr-Lys was cut into small portions, treated with TFA/H 2 O (95:5, 89.25 ml) and stored at room temperature overnight. Solid material was removed by filtration, washed with dichloromethane (×2) and methanol (×2), and the filtrates combined. Acid was removed by evaporation below 40° C., and the sample freed from acid by azeotropy from toluene/dichloromethane (2 x). The sample was dissolved in water (15 ml), filtered and freeze dried. The mass recovery was essentially quantitative. This was examined by hplc analysis and the desired material was shown to be the major product by comparison with a genuine sample, and moreover exhibited the desired m/e peak in the mass spectrum.
Preparation of a 1677 component peptoid library for biological screening:
Three sheets of amine functionalised paper as described above of dimensions 210×297mm were indelibly marked with a pattern of indicia (43 columns and 39 rows), and subsequently deprotected with TFA in the manner described above ready for the coupling of the first monomers. Analysis revealed the presence of 1.9 nmol/mm 2 of amine groups.
Functionalisation of the sheet:
Each of the 43 columns of paper was divided from the original sheet and separately functionalised as follows: Each column of paper was treated with an individual Fmoc-protected amino acid derivative pre-activated as its 2,4-dichlorophenyl 4-(oxymethyl) phenoxy acetate as described above in a solution of DMF (0.5 ml) and pyridine (10 ml) at room temperature overnight. The paper was washed with DMF (×4) and dichloromethane (×5) and dried at 40° C. for 30 min. Acetylation of residual amine functionality was carried out as described above.
Deprotection of the amine groups was also carried out as described above.
Coupling of the second monomer:
The complete set of stacked strips of reaction zones of the original paper sheets was assembled into one block and then cut again at right angles to the original cutting direction into individual reaction zones. Each set of individual reaction zones from a complete row was then coupled with a second Fmoc-protected monomeric unit, pre-activated as its 2,4-dichlorophenyl 4-(oxymethyl)phenoxy acetate ester as described above. On completion of reaction, these individual reaction zones were washed, acetylated, and finally the Fmoc protection group was removed as described above.
Coupling of the third monomer:
The complete set of 1677 individual reaction zones charged with dimeric amine derivatives were combined into one vessel, and reacted with diphenylacetyl chloride (2.31 g, 0.1 mol), with Hunig's Base (3.5 ml, 0.1 mol) in DMF (96.5 ml) at room temperature overnight. The set of individual reaction zone was washed with DMF (×3), and dichloromethane (×4) and dried at 40° C. for 30 min under vacuum. To remove all extraneous reagents, the complete set of reaction zones was treated in a Soxhlet extractor with dichloromethane overnight, and the extract discarded. The reaction zones were dried at 40° C. under vacuum for three hours.
Cleavage of individual trimeric products:
The trimeric products were removed from the paper in the following manner: Each individual labelled reaction zone was separated and treated with TFA/H 2 O (95:5, 50 ml) at room temperature overnight. Each reaction zone was then washed with dichloromethane (12×50 ml), methanol (4×50 ml), the washings being combined and evaporated under nitrogen. Analysis of individual products is exemplified by the following: After cleavage from the paper support, individual trimeric products were identified by the indicia marked thereon. A subset of these was examined by both hplc and mass spectrometry and, in the cases examined, confirmed the presence of the desired compound.
Below is a subset of typical analytical data for compounds examined by mass spectrometry:
__________________________________________________________________________IndiciaStructure Expected m/e Found m/e__________________________________________________________________________ A3410 533.62 535.0B3315 ##ST 541.62 543.0 - C3702 ##STR3## 432.41 432.8 - A0604 ##STR4# 538.61 539.0__________________________________________________________________________
EXAMPLE 2
Syntheses on aminomethyl-substituted laminated resin sheet
Preparation of aminomethyl-substituted laminar sheet:
A sample of 100 g of a partially cross-linked aminomethyl polystyrene resin (Novabiochem 01-640010) was thoroughly mixed with a sample of low melting thermoplastic polyethylene glue (Dritex DT157/300) and the mixture was evenly spread over the surface of a portion of non-woven fibrous polypropylene sheet (Freudenberg Lutrasil 4150) of area 16 square meters. A further sheet of the same non-woven fibrous polypropylene sheet of identical area was then superimposed onto the bottom loaded sheet, and the two were then heat welded together (within a temperature range of 90-140° C.) to give a single material containing resin in which amino groups were demonstrably available.
Titrimetric analysis of the free amine content showed that, in this example, free amine density was 2.2 nmole/mm 2 .
Fmoc-O-t-butyl-Ser Derivatisation:
A sample of the above polypropylene cloth (210×145 mm, or 67.8 mmole total amine content), indelibly identified with indicia, was derivatised by reaction with the 2,4-dichlorophenyl N-α-Fmoc-O-t-butyl-Ser-4-oxymethylphenoxyacetate ester (258 mg or 5 times excess) in DMF solution for a period of 17 hr at room temperature. The resin cloth was washed with DMF (×-3) to remove reagents and dichloromethane (×3), and was then dried at room temperature under vacuum.
Residual amine groups were acetylated using a solution of acetic anhydride (4 ml), collidine (6 ml) and 4-dimethylaminopyridine (2 g) in acetonitrile (20 ml) for 1 hr at room temperature. The resin cloth was then washed with acetonitrile (×3), dichloromethane (×6), and dried under vacuum.
Deprotection of the Fmoc group was achieved using a standard method utilising a solution of piperidine (10 ml) in DMF (10 ml) for 30 min at room temperature. Washing of the cloth with DMF (×4) and dichloromethane (×6), followed by drying under vacuum gave the material ready for the next coupling.
Fmoc-α-Boc-Lys Derivatisation:
A sample of the same polypropylene cloth of identical dimensions, indelibly identified with indicia, was derivatised in an identical fashion using instead the analogous derivative of Fmoc-α-Boc-Lys.
Residual amine acetylation, and deprotection prior to further functionalisation were performed in a manner identical to that described above.
Coupling of the second monomer:
The two above monomerically linked pieces of resin cloth were combined in one vessel and treated with a five-fold excess of a solution of the HOBt ester of Fmoc-O-t-butyl Tyr prepared by pre-activation of a solution of Fmoc-O-t-butyl Tyr (331 mg, 0.68 mmol), HOBt (92 mg, 0.68 mmol), TBTU (217 mg, 0.68 mmol) and Hunig's Base (120 ml, 0.68 mmol) in DMF for a period of 30 min. This pre-activated ester was then reacted with the pieces of resin cloth at room temperature overnight. The two pieces of resin cloth were then washed with DMF (×3) to remove reagents, dichloromethane (×6), and dried under vacuum.
Residual amine groups were acetylated using a solution of acetic anhydride (4 ml), collidine (6 ml), and 4-dimethylaminopyridine (2 g) in acetonitrile (20 ml) for 1 hr at room temperature. The resin cloth was then washed with acetonitrile (×3) and dichloromethane (×6), and dried under vacuum.
Deprotection of the Fmoc group was achieved using a standard method utilising a solution of piperidine (10 ml) in DMF (10 ml) for 30 min at room temperature. Washing of the cloth with DMF (×4) and dichloromethane (×6), followed by drying of the resin cloth under vacuum, gave the material ready for the next coupling.
Coupling of the third monomer:
The sample of resin cloth bearing Tyr-Ser was further reacted separately with a sample of the HOBt ester of Fmoc-O-t-butyl-Thr prepared by pre-activation of a solution of Fmoc-O-t-butyl Thr (134 mg, 0.339 mmol), HOBt (46 mg, 0.339 mmol), TBTU (108 mg, 0.339 mmol) and Hunig's Base (60 ml, 0.339 mmol) in DMF (10 ml) for a period of 30 min. The resin cloth was reacted at room temperature overnight with this preformed reagent.
The sample of resin cloth bearing Tyr-Lys was further reacted separately with a sample of the HOBt ester of α-Fmoc-Boc-Lys prepared by pre-activation of a solution of α-Fmoc-Lys (159 mg, 0.339 mmol), HOBt (46 mg, 0.339), TBTU (108 mg, 0.339 mmol) and Hunig's Base (60 ml, 0.339 mmol) in DMF (10 ml) for a period of 30 min. The resin cloth was reacted at room temperature overnight with this preformed reagent.
The two pieces of resin cloth were then washed with DMF (×3) to remove reagents, dichloromethane (×6), and dried under vacuum.
Residual amine groups were acetylated using a solution of acetic anhydride (4 ml), collidine (6 ml) and 4-dimethylaminopyridine (2 g) in acetonitrile (20 ml) for 1 hr at room temperature. The resin cloth was then washed with acetonitrile (×3), dichloromethane (×6), and dried under vacuum.
Final deprotection of the Fmoc group was achieved using a standard method utilising a solution of piperidine (10 ml) in DMF (10 ml) for 30 min at room temperature. Washing of the cloth with DMF (×4) and dichloromethane (×6), followed by drying under vacuum, gave the material ready for the final cleavage.
Cleavage of the trimers from the resin cloth:
The sample of resin cloth bearing Thr-Tyr-Ser was separately treated with TFA/H 2 O (95:5, 30 ml) and stored at room temperature overnight. The acid solution was removed from the cloth by filtration, was removed by evaporation below 40° C., and the sample freed from acid by azeotropy from toluene/dichloromethane (3 x). The mass recovery was essentially quantitative and the presence of the desired product was confirmed by hplc and ms analysis.
The sample of resin cloth bearing Lys-Tyr-Lys was separately treated with TFA/H 2 O (95:5, 30 ml) and stored at room temperature overnight. The acid was removed by evaporation below 40° C., and the sample freed from acid by azeotropy from toluene/dichloromethane (3 x). Again, the mass recovery was essentially quantitative and formation of the desired product was confirmed by hplc and ms analysis.
Preparation of a 27 component tripeptide library on resin cloth for biological screening:
Derivatisation with the first monomer (using α-Fmoc-ωn-Boc-Lys, Fmoc-Ser-O-t-butyl ether and Fmoc-Leu):
Three samples of the above polypropylene resin cloth (each 210×150 mm, or 68.7 mmol total amine content), each having reaction zones indelibly identified in a 3×3 grid pattern of indicia, were derivatised separately by reaction in DMF solution for a period of 17 hr at room temperature with 2,4-dichlorophenyl-α-Fmoc-aminoacyl-4-oxymethylphenoxyacetate (0.34 mmol or 5 times excess) derivatives of the amino acid monomers listed above. The resin cloth was washed with DMF solution (×3) to remove reagents, dichloromethane (×5) and was then dried at room temperature under vacuum for 15 min.
Residual amine groups were acetylated on the whole set of sheets using a solution of acetic anhydride (6 ml), collidine (9 ml) and 4-dimethylaminopyridine (3 g) in acetonitrile (30 ml) for 1 hr at room temperature. The resin cloth was then washed with acetonitrile (×4) and dichloromethane (×6), and dried under vacuum for 1 hr.
Deprotection of the Fmoc group was achieved using a standard method utilising a solution of piperidine (15 ml) in DMF (15 ml) for 30 min at room temperature. Washing of the cloth with DMF (×4) and dichloromethane (×6), followed by drying of the cloth under vacuum, gave the material ready for the next coupling.
Derivatisation with the second monomers (using FmocTyr-O-t-butyl ether, FmocSer-O-t-butyl ether and Fmoc Phe):
The original sheets were divided into three columns, and each set of three columns of three reaction zones was reacted separately with the second monomer. Each of the nine monomerically linked pieces of resin cloth in three columns was combined in one vessel and treated with a five-fold excess of a solution of the HOBt ester of the above Fmoc-amino acid preformed from Fmoc-amino acid (0.343 mmol, 5 times excess), HOBt (46 mg, 0.343mmol), TBTU (108 mg, 0.343 mmol) and Hunig's Base (60 ml, 0.343 mmol) by reaction in DMF (10 ml) for a period of 30 min. This was then reacted at room temperature overnight with the samples of resin cloth. The pieces of resin cloth were then washed to remove reagents using DMF (×3), dichloromethane (×5), and dried under vacuum at room temperature for 15 min.
Residual amine groups were acetylated using a solution of acetic anhydride (6 ml), collidine (9 ml) and 4-dimethylaminopyridine (3 g) in acetonitrile (30 ml) for 1 hr at room temperature. The resin cloth was then washed with acetonitrile (×4), dichloromethane (×6), and dried under vacuum for 1 hr.
Deprotection of the Fmoc group was achieved using a standard method utilising a solution of piperidine (15 ml) in DMF (15 ml) for 30 min at room temperature. Washing of the cloth with DMF (×4) and dichloromethane (×6) followed by drying of the resin cloth under vacuum gave the material ready for the final coupling.
Coupling of the third monomers (using FmocThr-O-t-butyl ether, αFmoc-ω-Boc-Lys and Fmoc-Gly):
The samples of resin cloth were divided into their individual portions by cutting in a direction orthogonal to the first cut. Each set of samples of resin cloth bearing dimeric units was further reacted separately with a sample of the HOBt-ester of Fmoc-amino acids as listed above, prepared by pre-activation of a solution of Fmoc-amino acid (0.343 mmol), HOBt (46 mg, 0.343 mmol), TBTU (108 mg, 0.343 mmol) and Hunig's Base (60 ml, 0.343 mmol) in DMF (10 ml) for a period of 30 min. The resin cloth was then reacted at room temperature overnight with this pre-activated reagent. Each individual piece of resin cloth was then washed to remove reagents with DMF (×3) and dichloromethane (×6), and dried under vacuum.
Residual amine groups were acetylated using a solution of acetic anhydride (6 ml), collidine (9 ml) and 4-dimethylaminopyridine (3 g) in acetonitrile (30 ml) for 1 hr at room temperature. The resin cloth was then washed with acetonitrile (×4), dichloromethane (×6), and dried under vacuum.
Final deprotection of the Fmoc group was achieved using a standard method utilising a solution of piperidine (15 ml) in DMF (15 ml) for 30 min at room temperature. Washing of the cloth with DMF (×4) and dichloromethane (×6), followed by drying under vacuum, gave the material ready for the final cleavage.
Cleavage of trimers from the resin cloth:
Each sample of resin cloth bearing an individual trimeric unit was separately treated with TFA/H 2 O (95:5, 2 ml) and stored at room temperature overnight. The cloth was separated by filtration, and washed with dichloromethane (2 ml×12), methanol (2 ml×4), and the washings combined. The acid was removed by evaporation below 40° C., and the sample freed from acid by azeotropy from toluene/dichloromethane (3 x). The mass recovery was essentially quantitative and formation of the desired products was confirmed by hplc and ms analysis in comparison with an authentic sample. Results are given below:
______________________________________Entry number Structure Expected m/e Found m/e______________________________________1 ThrTyrLys 410.46 411.0 2 LysTyrLys 437.56 438.2 3 GlyTyrLys 366.46 367.3 4 ThrPheLys 394.46 395.6 5 LysPheLys 421.56 422.5 6 GlyPheLys 350.46 351.7 7 TheSerLys 334.46 335.0 8 LysSerLys 361.46 362.6 9 GlySerLys 290.36 291.5 10 ThrTyrSer 369.36 370.0 11 LysTyrSer 396.46 396.9 12 GlyTyrSer 325.36 326.6 13 ThrPheSer 353.36 354.1 14 LysPheSer 380.46 381.4 15 GiyPheSer 309.36 309.8 16 ThrSerSer 292.90 294.2 17 LysSerSer 320.36 321.3 18 GlySerSer 249.26 250.4 19 ThrTyrLeu 395.46 395.8 20 LysTyrLeu 422.56 423.3 21 GlyTyrLeu 351.46 352.1 22 ThrPheLeu 379.46 380.1 23 LysPheLeu 406.56 407.1 24 GlyPheLeu 335.46 336.6 25 ThrSerLeu 319.36 320.6 26 LysSerLeu 346.46 347.5 27 GlySerLeu 275.36 276.1______________________________________
Preparation on resin cloth of a 1677 component library for biological screening:
Three sheets of the polypropylene resin cloth described above of dimensions 210×297mm were indelibly marked with a pattern of indicia (43 columns and 39 rows), ready for the coupling of the first monomers. Analysis revealed the presence of 2.18 nmol/mm 2 of amine groups.
Functionalisation of the sheet:
Each column of polypropylene resin cloth was divided from the original sheet, and separately functionalised by treatment with an individual Fmoc protected amino acid derivative pre-activated as its 2,4-dichlorophenyl 4-(oxymethyl)phenoxy acetate as described above in a solution of DMF (0.5 ml) and pyridine (10 ml) at room temperature overnight. The cloth strips were washed with DMF (×4) and dichloromethane (×5) and dried at 40° C. for 30 min. Acetylation of residual amine functionality was carried out as described above.
Deprotection of the amine groups was also carried out as described above.
Coupling of the second monomer:
The complete set of columns of the original polypropylene resin sheets was assembled into one block and cut into individual pieces. Each set of pieces from individual rows was then coupled with a second Fmoc-protected monomeric unit, pre-activated as its 2,4-dichlorophenyl 4-(oxymethyl)phenoxy acetate ester as described above. Upon completion of reaction, these were washed, acetylated and, finally, the Fmoc protection group was removed as described above.
Coupling of the third monomer:
The complete set of 1677 individual dimeric amine derivatives was reacted with diphenylacetyl chloride (2.31 g, 0.1 mol) and Hunig's Base (3.5 ml, 0.1 mol) in DMF (96.5 ml) at room temperature overnight in smaller subsets. Each set of polypropylene resin cloth pieces was washed with DMF (×3), dichloromethane (×4) and dried at 40° C. for 30 min under vacuum.
Cleavage of individual trimeric products from the polypropylene cloth:
Individual labelled resin cloth pieces were separated and treated with TFA/H 2 O (95:5, 50 ml) at room temperature overnight. Each was then washed with acetonitrile/water (1:1, 3×100 ml), the washings combined and evaporated under vacuum centrifugation. After cleavage from the resin cloth support, individual trimeric products were identified by the indicia marked thereon. A subset of these was examined by both hplc and mass spectrometry and, in the cases examined, confirmed the formation of the desired compounds.
A subset of typical analytical data for compounds examined by mass spectrometry is given below:
__________________________________________________________________________IndiciaStructure Expected m/e Found m/e__________________________________________________________________________ B3412 487.59 487.00B2412 ##ST 458.54 475.0* - C3408 ##STR7## 488.57 489.00 - A3408 ##STR8# 486.59 505.1*__________________________________________________________________________ *MNH.sup.4+ -
The choice of resins is not limited to the single form specified in the foregoing example. The laminar sheet may be prepared from a wide range of alternative resins. It will be appreciated that different types of resin permit differing types of chemistry to be carried out, some of which are exemplified, but not limited, by the following:
The preparation of oligosaccharides is conveniently carried out on a polymeric (ethylene glycol) ω-monomethyl ether, (see Douglas, S. P., Whitfield, D. M., Krepinsky, J. J, J. Amer. Chem. Soc., 1995, 117, 2116) or alternatively on a poly(p-(propen-3-OH-1-yl)) linked polystyrene.
Preparation of a series of serine phosphopeptides was carried out on Wang resin (see Shapiro, G., Swoboda, R., Stauss, U., Tetrahedron Letters, 1994, 35, 869).
Tentagel resin has been found to be useful for the formation of C-C bonds such as the Heck reaction, (see Hiroshauge, M, Hauske, J. R., Zhou, P., Tetrahedron Letters, 1995, 36, 4567) and other C--C bond forming processes such as the Stille reaction may be conveniently carried out on Rink amide functionalised polystyrene, (see Forman, F. W., Sucholeiki, I., J. Org. Chem., 1995,60,523).
A series of aspartic acid protease inhibitors has been prepared on a dihydropyran functionalised resin, (see Kick, E. K., Ellman, J. A., J. Med. Chem., 1995,38,1427) and examples of aryl ether formation via the Mitsonobu reaction have been successfully carried out on Tentagel S RAM Fmoc resin, (see Rano, T. A., Chapman, K. T., Tetrahedron Letters, 1995,36,3789).
It will be appreciated by those skilled in the art that there are many further examples in the literature of alternative resins suitable for still further chemistry to be carried out. | The instant invention is directed to a method of making a library of compounds using a segmentable support material comprised of a particulate resin affixed to a porous laminar material. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of U.S. patent application Ser. No. 10/167,382 filed Jun. 10, 2002 now U.S. Pat. No. 6,781,888, which is a continuation-in-part of U.S. patent application Ser. No. 10/100,705, filed Mar. 18, 2002. These two parent applications are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the field of semiconductor capacitively coupled negative differential resistance (“NDR”) devices for data storage, and more particularly to reference cells to be used therewith.
2. Description of the Prior Art
U.S. Pat. No. 6,229,161 issued to Nemati et al., incorporated herein by reference in its entirety, discloses capacitively coupled NDR devices for use as SRAM memory cells. The cells disclosed by Nemati et al. are hereinafter referred to as thinly capacitively coupled thyristor (“TCCT”) based memory cells. FIG. 1 shows a pair of representative TCCT based memory cells 10 as disclosed by Nemati et al., and FIG. 2 shows a cross-section through one TCCT based memory cell 10 along the line 2 — 2 . FIG. 3 shows a schematic circuit diagram corresponding to the embodiment illustrated in FIGS. 1 and 2 . The TCCT based memory cell 10 includes an NDR device 12 and a pass transistor 14 . A charge-plate or gate-like device 16 is disposed adjacent to, and in the case of the illustrated embodiment, surrounding, the NDR device 12 . A P+ region 18 of the NDR device 12 is connected to a metallization layer 20 so that a first voltage V 1 , such as V ddarray , can be applied to the NDR device 12 through the P+ region 18 . An N+ region of the NDR device 12 forms a storage node 22 that is connected to a source of the pass transistor 14 . Where the pass transistor 14 is a MOSFET, it can be characterized by a channel length, L, and a width, W, where L is the spacing between the source and the drain, and W is the width of the pass transistor 14 in the direction perpendicular to the page of the drawing in FIG. 2 . Assuming a constant applied voltage, a current passed by pass transistor 14 will scale proportionally to a ratio of W/L.
Successive TCCT based memory cells 10 are joined by three lines, a bit line 26 , a first word line (WL 1 ) 28 , and a second word line (WL 2 ) 30 . The bit line 26 connects a drain 32 of pass transistor 14 to successive TCCT based memory cells 10 . In a similar fashion, pass transistor 14 includes a gate 34 that forms a portion of the first word line 28 . Likewise, the gate-like device 16 forms a portion of the second word line 30 .
Memory arrays of the prior art typically include a large number of memory cells that are each configurable to be in either of two states, a logical “1” state or a logical “0” state. The memory cells are typically arranged in rows and columns and are connected to a grid of word lines and bit lines. In this way any specific memory cell can be written to by applying a signal to the appropriate word lines. Similarly, the state of a memory cell is typically manifested as a signal on one of the bit lines. In order to correctly interpret the state of the memory cell from the signal on the bit line, memory arrays of the prior art typically rely on some form of a reference signal against which the signal on the bit line is compared.
One type of memory array of the prior art uses SRAM cells for the memory cells. A conventional SRAM cell stores a voltage and includes two access ports, data and data-bar, where data-bar is a complementary signal to data and serves as a reference. A sensing circuit for the conventional SRAM cell compares the voltages of data and data-bar to determine whether the SRAM cell is storing a “1” or a “0.”
Another type of memory array of the prior art uses DRAM cells for the memory cells. A conventional DRAM cell is a capacitor and stores a charge to represent a logical state. When a DRAM cell is read it produces a voltage on a bit line. A typical reference cell for a DRAM memory array is a modified DRAM cell designed to store about half as much charge as the conventional DRAM cell. Accordingly, in a DRAM memory array the voltage produced by the DRAM cell is compared to the voltage produced by the reference cell to determine whether the DRAM cell is storing a “1” or a “0.”
In comparison to the conventional SRAM cell, a TCCT based memory cell 10 has only a single port, namely bit line 26 . In further comparison to both the SRAM and DRAM cells, the TCCT based memory cell 10 does not produce a voltage but instead produces a current. More specifically, TCCT based memory cell 10 has an “on” state wherein it generates a current that is received by bit line 26 . TCCT based memory cell 10 also has an “off” state wherein it produces essentially no current. Accordingly, voltage-based reference cells of the prior art are inadequate for determining the state of a TCCT based memory cell 10 and a new type of reference is needed.
A reference cell to be used in a memory array of TCCT based memory cells 10 should produce a reference current with an amount that is somewhere within the range defined by the currents generated by TCCT based memory cell 10 in the “on” and “off” states, and preferably about half the magnitude of the current generated by TCCT based memory cell 10 in the “on” state. It is well known, however, that the amount of current produced by TCCT based memory cell 10 varies as a function of temperature, variations in manufacturing, operating conditions (i.e., voltages), among other things. Therefore, what is desired is a reference cell capable of generating a reference current that will remain at a suitable magnitude such as about half the intensity of the current generated by a TCCT based memory cell 10 in the “on” state despite variations in manufacturing and operating conditions.
SUMMARY
A reference cell for a TCCT based memory cell includes an NDR device, a switch, and a current reduction element arranged together with a bit line and two word lines. The NDR device includes a doped semiconductor layer between first and second ends, the first end configured to have a first voltage applied thereto. The NDR device also includes a gate-like device disposed adjacent to the doped semiconductor layer. The switch is preferably a pass transistor that includes a source coupled to the second end of the NDR device, a drain, and a gate coupled to the first word line. The second word line is coupled to the gate-like device. The current reduction element is coupled between the bit line and the drain of the pass transistor. In some embodiments the current reduction element is a second pass transistor including a gate having a second voltage applied thereto. In these embodiments the reference cell produces an amount of current that is sufficient to be used as a reference. By applying an appropriate voltage to the second pass transistor, the second pass transistor can be made to have an appropriate resistance such that the desired current reduction is obtained.
These embodiments are advantageous in that a reference cell can be made to be in every respect the same as a TCCT based memory cell with the additional feature of a current reduction element. This way a reference current produced by the reference cell will be less than the amount of current produced by the TCCT based memory cell in the “on” state. In other embodiments the same advantages are achieved with an NDR device as described coupled to a single pass transistor. In these embodiments a voltage is applied to a gate of the single pass transistor such that it produces a resistance equal to the sum of the resistances of the first and second pass transistors in the previous embodiments.
Other embodiments of the invention are directed to a circuit for generating a reference voltage to control a current output of a reference cell. These embodiments allow the current output from a reference cell of the invention to be continuously maintained at any desired value, though preferably at about half of the amount of current produced by a TCCT based memory cell. The circuit to generate a reference voltage includes a TCCT based memory cell to produce a first current, a pair of reference cells as described above, each producing a current, and a feedback circuit. In these embodiments the reference cell produces the reference voltage from the feedback circuit which varies the reference current as a function of the difference between the first current and the sum of the two currents from the reference cells. The generated reference voltage is also applied to the second pass transistors to provide feedback to the two reference cells.
In specific embodiments the reference voltage is adjusted so that each reference cell produces a current equal to half of the current produced by the TCCT based memory cell. These embodiments can be advantageously used to apply the same reference voltage to a pass transistor in another reference cell outside of the circuit so that it will also produce a current equal to half of the current produced by the memory cell.
Other embodiments of the invention are directed to a memory array including a TCCT based memory cell coupled to a first bit line, a reference cell coupled to a second bit line, and means for determining a state of the TCCT based memory cell by comparing a first current on the first bit line and a second current on the second bit line. Still other embodiments of the memory array further include a circuit to generate a reference voltage to control a current output of a reference cell, as described above.
Still other embodiments are directed to a method of producing a reference current against which a current from a TCCT based memory cell can be compared. In these embodiments a reference cell and a circuit to produce a reference voltage are both provided. The reference cell includes an NDR device configured to produce a current and a pass transistor connected to the NDR device. The circuit is configured to produce a reference voltage that is applied to the gate of the pass transistor. In this way a current produced by the NDR device is reduced by the resistance of the pass transistor so that a reference current is obtained. The degree to which the current produced by the NDR device is reduced is determined by the magnitude of the reference voltage applied to the gate of the pass transistor.
Yet other embodiments are directed to a method for reading a state of a TCCT based memory cell. In these embodiments the method includes operating the TCCT based memory cell to produce a first current on a first bit line, operating a reference cell to produce a second current on a second bit line, operating a circuit to provide a reference voltage to the reference cell, and comparing the first and second currents. Operating the TCCT based memory cell includes both applying a voltage to one end of the TCCT based memory cell to generate a current, and applying another voltage to a gate of a pass transistor to connect the TCCT based memory cell to the first bit line. The reference cell is similarly operated. The circuit is operated by operating a circuit memory cell and a circuit reference cell. The circuit memory cell is a dedicated TCCT based memory cell that is not used for memory purposes; instead it is used to produce a current that is representative of the current produced by other TCCT based memory cells in an array. The circuit reference cell is also dedicated to the circuit and likewise is used to produce a current that is representative of the current produced by other reference cells in the array. A feedback circuit is configured to receive the currents produced by the circuit memory cell and the circuit reference cell, provide a reference voltage to the circuit reference cell to controls the current output of the circuit reference cell, and to adjust the reference voltage until the current from the circuit reference cell is about half of the current from the circuit memory cell.
BRIEF DESCRIPTION OF DRAWINGS
The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings where like reference numerals frequently refer to similar elements and in which:
FIG. 1 shows a TCCT based memory cell of the prior art;
FIG. 2 shows a cross-section of the TCCT based memory cell of FIG. 1 ;
FIG. 3 shows a schematic circuit diagram of the TCCT based memory cell of FIG. 1 ;
FIG. 4 shows a schematic circuit diagram of an exemplary reference cell of a specific embodiment the invention;
FIG. 5 shows a schematic circuit diagram of another example of a reference cell in accordance with another embodiment of the invention;
FIG. 6A shows a schematic circuit diagram of an exemplary NDR based reference voltage generator circuit according to an embodiment of the invention;
FIG. 6B shows a schematic circuit diagram of an exemplary SRAM based reference voltage generator circuit according to an embodiment of the invention;
FIG. 6C shows a schematic circuit diagram of an exemplary MRAM based reference voltage generator circuit according to an embodiment of the invention;
FIG. 6D shows a schematic circuit diagram of an exemplary flash memory based reference voltage generator circuit according to an embodiment of the invention;
FIG. 7 shows a schematic circuit diagram of another example of a reference voltage generator circuit of another embodiment of the present invention;
FIG. 8 shows a block diagram illustrating an example of a feedback circuit according to an embodiment of the invention;
FIG. 9 shows a schematic circuit diagram of an example of a current comparator of the invention;
FIG. 10 shows a schematic circuit diagram of an example of a ramp output voltage generator of the invention;
FIG. 11 shows a memory array including an exemplary reference cell for each bit line in accordance with a specific embodiment;
FIG. 12 shows another memory array including another example of a reference cell for each bit line in accordance with another embodiment;
FIG. 13 shows a schematic circuit diagram of an exemplary NDR based reference voltage generator circuit according to another embodiment of the invention; and
FIG. 14 shows a schematic circuit diagram of another exemplary memory array 220 of the invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 4 shows a schematic circuit diagram of an exemplary reference cell 40 in accordance to a specific embodiment of the invention. As in the TCCT based memory cell 10 ( FIG. 1 ), the reference cell 40 includes an NDR device 42 having a first end connected to a source of a pass transistor 44 . A gate-like device 46 is disposed adjacent to the NDR device 42 . A first word line 48 is connected to a gate of the pass transistor 44 , a second word line 50 is connected to the gate-like device 46 , and a first voltage V 1 , such as V ddarray , can be applied to the NDR device 42 at a second end.
Reference cell 40 also includes a current reduction element 52 connected between a drain of the pass transistor 44 and a bit line 54 . The current reduction element 52 prevents a certain amount of a current produced by the NDR device 42 from reaching the bit line 54 . In a specific embodiment, the current reduction element 52 reduces the current reaching the bit line 54 by a predetermined amount such as about ½. Current reduction element 52 can take many forms, the simplest of which is a resistor having an appropriate resistance. In other embodiments, current reduction element 52 is a transistor and the appropriate resistance is produced by adjusting a gate length. In a similar fashion, instead of adding a separate element as the current reduction element 52 , the function is added to pass transistor 44 by providing it with a longer gate length than a pass transistor 14 ( FIG. 1 ). Another method for reducing the current reaching the bit line 54 is to vary aspects of the NDR device 42 in such a way as to decrease its current output when in a low resistance (“on”) state, for example by providing the NDR device 42 with a narrower gate width. Each of these reference cell 40 embodiments is capable of producing a reference current, however, none effectively produce a reference current that varies proportionally with a current from a TCCT based memory cell 10 ( FIG. 1 ) as temperature is varied so that the desired ½ ratio is maintained. Manufacturing variability over each process corner can also make it difficult to produce the desired ½ ratio in these embodiments. In another example, current reduction element 52 has a variable resistance so that the desired current can be maintained on the bit line 54 by increasing as well as decreasing the resistance of current reduction element 52 .
FIG. 5 shows a second pass transistor 56 serving to reduce the current from the NDR device 42 . The second pass transistor 56 is controlled by a variable reference voltage V REF 58 . A feedback loop monitoring the current on the bit line 54 can be used to continuously adjust the reference voltage 58 to adjust the resistance of the second pass transistor 56 .
FIG. 6A shows a schematic circuit diagram of an exemplary reference voltage generator circuit 60 including a TCCT based memory cell 62 and two reference cells 64 and 66 . All three cells 62 , 64 , and 66 are connected to a common line 68 carrying a first voltage V 1 and to common first and second word lines 70 and 72 , as shown. Accordingly, all three cells 62 , 64 , and 66 operate in parallel such that all three produce current at the same time. The TCCT based memory cell 62 produces a first current I 1 and the two reference cells 64 and 66 produce second and third currents I 2 and I 3 , respectively.
The reference voltage generator circuit 60 also includes a feedback circuit 74 . The feedback circuit 74 is configured to receive two inputs, I 1 from the TCCT based memory cell 62 and the summed currents I 2 and I 3 from reference cells 64 and 66 . Ideally, I 2 and I 3 should always be the same as reference cells 64 and 66 are fabricated to be the same and are operated by the same voltages. The feedback circuit 74 is also configured to output a variable reference voltage V REF 76 . The variable reference voltage V REF 76 is configured to be applied to the second pass transistors 78 and 80 . It can be seen that as variable reference voltage V REF 76 is varied the resistances of second pass transistors 78 and 80 also vary and that the currents I 2 and I 3 also vary. It can further be seen that the feedback circuit 74 can therefore continually adjust the variable reference voltage V REF 76 so that I 2 +I 3 is maintained to be equal to I 1 . Provided that I 2 equals I 3 , when I 2 +I 3 =I 1 then each of I 2 and I 3 is equal to ½I 1 .
It will be understood that the embodiment shown in FIG. 6A is but one specific embodiment. In another embodiment, two or more TCCT based memory cells 62 are employed and their output currents are summed before entering the feedback circuit 74 . In this embodiment, for each additional TCCT based memory cell 62 two more reference cells 64 and 66 are also added. For example, where 3 TCCT based memory cells 62 are employed, the outputs of 6 reference cells would be summed as the second input to the feedback circuit 74 . While this embodiment requires more devices and uses more space on a die, it has the advantage that the variable reference voltage V REF 76 is the product of an averaging over many cells and is therefore less sensitive to minor variations between the cells. In still other embodiments different ratios of reference cells to TCCT based memory cells 62 are employed. For example, 4 reference cells to one TCCT based memory cell 62 would yield a variable reference voltage V REF 76 that when applied to a reference cell would cause the reference cell to produce a current equal to ¼I 1 . Other examples can be readily envisioned by one having ordinary skill in the art.
It will also be understood that although the embodiments shown in the various drawings such as FIG. 6A are specific to NDR devices and TCCT based memory cells, the invention is more broadly applicable to any memory device that produces a variable current depending on a stored state. As an example, FIG. 6B illustrates another embodiment of a reference voltage generator circuit 81 in which the NDR devices have been replaced with SRAM cells 83 . Similarly, FIGS. 6C and 6D illustrate additional embodiments of a reference voltage generator circuit 85 , 89 in which the NDR devices have been replaced either with MRAM cells 87 or memory cells with floating gates such as flash memory cells 91 . It will be further apparent that in the present invention it is possible to use a combination of different current-producing memory devices. For example, in FIG. 6A the reference cells 64 and 66 can be made with SRAM cells 83 as in FIG. 6B , while the memory cell 62 can include an NDR device as shown.
In yet another embodiment, the first pass transistors of the reference cells are removed, as shown in FIG. 7 . Instead, second pass transistors 82 and 84 are made to each have a resistance greater than the resistances of second pass transistors 78 and 80 ( FIG. 6A ) by the additional resistance of the pass transistor 44 ( FIG. 4 ). Second pass transistors 82 and 84 can be made to have the additional resistance, for example, by operating at a variable reference voltage V REF 86 that is higher than the variable reference voltage V REF 76 ( FIG. 6A ). The additional resistance can also be obtained by adjusting a gate length of each of the second pass transistors 82 and 84 . In another embodiment, the pass transistor associated with WL 1 and I 1 is optional and is absent from the circuit depicted in FIG. 7 .
Referring back to FIG. 5 , it will be apparent that the variable reference voltage V REF 76 can also be applied to the second pass transistor 56 of a reference cell outside of the reference voltage generator circuit 60 to generate a current on bit line 54 equal to ½I 1 . Because the variable reference voltage V REF 76 of FIG. 7 is variable, as conditions such as temperature change causing the current I 1 to change, the feedback circuit 74 can continually adjust the variable reference voltage V REF 76 so that the currents I 2 and I 3 each remain equal to ½I 1 . Similarly, the current on bit line 54 of FIG. 5 will also be adjusted to remain equal to ½I 1 as the conditions vary, provided that the conditions vary uniformly over the reference voltage generator circuit 60 and the outside reference cell which could be, for example, on a different part of the same die. In some embodiments, to increase the ratio of memory cells to reference cells in order to increase the overall density of memory cells on a die, a single reference cell will be located in a central location such as next to a sense amplifier configured to compare an output current from the reference cell to an output current from any of the memory cells.
FIG. 8 is a block diagram illustrating one possible feedback circuit 88 including a current comparator 90 and a ramp output voltage generator 92 in accordance with a specific embodiment of the invention. The current comparator 90 continuously monitors the first current I 1 and the sum of currents I 2 and I 3 . If the sum of currents I 2 and I 3 is greater than I 1 the current comparator 90 signals the ramp output voltage generator 92 to be in an active state in which it progressively decreases the voltage of variable reference voltage V REF 76 . Decreasing the variable reference voltage V REF 76 will, in turn, decrease the summation of currents I 2 and I 3 . Once the sum of currents I 2 and I 3 equals or falls just slightly below the first current I 1 the current comparator 90 signals the ramp output voltage generator 92 to be in an inactive state in which the voltage of variable reference voltage V REF 76 is held constant. In another embodiment, once the sum of currents I 2 and I 3 equals or falls just slightly below the first current I 1 the current comparator 90 signals the ramp output voltage generator 92 to be in an active state in which it progressively increases the voltage of variable reference voltage V REF 76 . Increasing the variable reference voltage V REF 76 will, in turn, increase the summation of currents I 2 and I 3 until the summed currents equal the first current I 1 . One having ordinary skill in the art should appreciate that the feedback circuit can operate to ramp up or down the reference voltage to properly set the reference current.
FIG. 9 shows a schematic circuit diagram of an exemplary current comparator 90 . Although the particular embodiment shown in FIG. 9 operates on an appropriate duty cycle to periodically compare the first current I 1 with the sum of currents I 2 and I 3 , it will be understood that a current comparator 90 can also operate with continuous sampling. In the exemplary current comparator depicted in FIG. 9 , MOSFET devices M 1 , M 2 , M 3 and M 4 form a CMOS cross-coupled latch operating as a high gain positive feedback amplifier where such configuration is well known in the art. MOSFET devices M 5 and M 6 are biased in their linear regions and provide for a low-impedance clamp between the input currents and a common potential, such as ground. The current comparator operates in two phases: (1) a pre-charge phase and (2) a sensing phase. In the pre-charge phase, the pre-charge signal is high and the sense signal is low. Device M 7 and M 8 are activated and thus equalize the potentials of devices M 2 and M 4 (i.e., logic low or ground). Therefore, the voltage at node A is driven to be equal to node B (i.e., V A equals V B ). In an alternate embodiment, the geometric ratios and sizes of devices M 3 and M 4 are designed to be different than devices M 1 and M 2 so that the point at which a current difference triggers a difference in voltages at nodes A and B is optimized. One having ordinary skill in the art should appreciate how to implement such design considerations by configuring the appropriate device size.
During the sensing phase, the pre-charge signal is low and the sense signal is high. Currents I 1 and the sum of currents I 2 and I 3 flow into devices M 5 and M 6 , respectively. Differences between currents I 1 and the sum of currents I 2 and I 3 generates a difference in between currents I A and I B , which in turn leads to a difference in voltages between nodes A and B. For example, if the sum of currents I 2 and I 3 is greater than current I 1 , then the capacitor C ref will contain more charge over time (i.e., discharges slower) than C 1 . With C ref having more charge over time than C 1 , the voltage at node B is shifted to a higher potential than node A.
As the voltage at node B increases and approaches a higher potential (e.g., V dd ), the degree in which device M 2 is turned on also increases. When M 2 is turned on, node A reaches a potential of about zero volts while conversely node B increases to high potential, such as V dd , as device M 3 increasingly turns on. Therefore, if the sum of currents I 2 and I 3 is greater than current I 1 , node B will be driven high and that state will be latched into the latch as V cnt . Otherwise, if the sum of currents I 2 and I 3 is less than current I 1 , node B will be driven low and that state will be latched into the latch as V cnt .
FIG. 10 shows a schematic circuit diagram of but one possible embodiment of a ramp output voltage generator 92 according to the present invention. Devices M 11 and M 13 and devices M 12 and M 16 form current mirrors designed so that I 13 mirrors I 11 and I 16 mirrors I 12 . Currents I 12 and I 11 are generated by constant current sources as are known in the art. Devices M 14 and M 15 operate as switches to either charge or discharge the capacitor at the positive input of the amplifier. For example, if node B latches V cnt at a high level, device M 15 will be turned on, thus discharging the capacitor. In turn, the voltage difference between the amplifier inputs will be as such as to decrease the variable reference voltage V ref . In particular, when the sum of currents I 2 and I 3 is greater than current I 1 , V ref will decrease to reduce the sum of currents I 2 and I 3 until the sum is substantially equivalent to current I 1 . The opposite actions occur when node B latches V cnt at a low level and turns on device M 14 to charge the capacitor. One having ordinary skill in the art should appreciate how to adapt and to modify the exemplary circuits shown in FIGS. 9 and 10 to practice the present invention.
FIG. 11 shows a memory array 110 including a plurality of TCCT based memory cells arranged by rows and columns. Each row includes a series of TCCT based memory cells and a reference cell sharing a common bit line. During a read operation a TCCT based memory cell in a first row produces a current on a first bit line while a reference cell in another row produces a reference current on another bit line. A controller (not shown) contains logic required to select individual TCCT based memory cells and to select a reference cell on a different bit line. The two currents on the two bit lines are then compared, for example, at a sense amplifier to determine the state of the TCCT based memory cell. In other embodiments, the memory array includes a single reference cell near the sense amplifier instead of devoting space to a reference cell on each row in the memory array 110 . In other embodiments a reference cell is placed on every n th row. Many other variations will be readily apparent to one having ordinary skill in the art.
FIG. 12 shows a memory array 120 that is similar to memory array 110 . Memory array 120 differs from memory array 110 only in that the reference cells are of the embodiment used in the circuit shown in FIG. 7 . It will be appreciated that the exemplary reference cell circuit shown in FIG. 7 is compatible in use with memory array 120 shown in FIG. 12 . Similarly, the exemplary reference cell circuit shown in FIG. 6A is likewise compatible in use with memory array 110 shown in FIG. 11 .
Referring again to FIG. 6A , it will be appreciated that although the invention has been described in terms of NDR devices, the reference voltage generator circuit 60 would still work if the NDR device and its nearest pass transistor in the TCCT based memory cell 62 were replaced with some other current-producing memory device. Likewise, the NDR device and its nearest pass transistor in the two reference cells 64 and 66 can also be replaced with some other current-producing memory device. A reference voltage generator circuit 60 is also useable with a memory array 110 where the TCCT based memory cells are replaced with another current-producing memory device.
FIG. 13 is a schematic circuit diagram of another exemplary reference voltage generator circuit 200 of the invention. The reference voltage generator circuit 200 including a memory cell 202 and two reference cells 204 and 206 . The memory cell 202 is coupled between a first line 208 at a first voltage V 1 and a feedback circuit 210 , as shown. The memory cell 202 is configured to produce a first current I 1 that is received by the feedback circuit 210 . In FIG. 13 the memory cell 202 is shown as a TCCT based memory cell including an NDR device 212 coupled to a pass gate 214 , however, just as in FIGS. 6B , 6 C, and 6 D, the memory cell 202 can be of another type such as SRAM or MRAM, or can be a memory cell with a floating gate such as a flash memory cell.
Reference cells 204 and 206 are coupled in parallel between feedback circuit 210 and a second line 216 coupled to an output node 218 of feedback circuit 210 . Reference cell 204 is configured to produce a second current I 2 and reference cell 206 is configured to produce a third current I 3 , where both currents are received at the feedback circuit 210 . The second and third currents can either be combined on a common line 220 as shown, or can be summed (i.e. combined) at the feedback circuit 210 . In FIG. 13 the reference cells 204 , 206 are shown as TCCT based reference cells, however, the invention will also work with other types of reference cells such as SRAM or MRAM, or a memory cell with a floating gate such as a flash memory cell.
The feedback circuit 210 operates as described above with reference to FIG. 6A to produce a reference voltage V ref at output node 218 by comparing the first current I 1 against the sum of the second current I 2 and the third current I 3 . When the sum of the second current I 2 and the third current I 3 is less than the first current I 1 the reference voltage V ref is increased. By increasing the reference voltage V ref , the voltage applied to the reference cells 204 and 206 is also increased. By increasing the voltage applied to the reference cells 204 and 206 both will produce more current until the sum of the second current I 2 and the third current I 3 is approximately equal to the first current I 1 . Similarly, if the sum of the second current I 2 and the third current I 3 is more than the first current I 1 the reference voltage V ref is decreased by the feedback circuit 210 until the sum of the second current I 2 and the third current I 3 is approximately equal to the first current I 1 .
Another exemplary reference voltage generator circuit includes reference cell 204 but omits reference cell 206 . In this embodiment the feedback circuit 210 compares the second current I 2 to the first current I 1 and generates a reference voltage in response thereto. Here, the feedback circuit increases the reference voltage V ref when the second current I 2 is less than about half of the first current I 1 and decreases the reference voltage V ref when the second current I 2 is greater than about half of the first current I 1 . Alternatingly, reference cells 204 , 206 can be accompanied by one or more additional reference cells in parallel similar to the reference cells described in connection with FIG. 6A .
FIG. 14 is a schematic circuit diagram of a representation of a portion of another exemplary memory array 220 of the invention. Memory array 220 includes a memory cell 222 coupled to a first bit line 224 , and a reference voltage generator circuit 226 coupled to a reference cell 228 that is in turn coupled to a second bit line 230 . A suitable reference voltage generator 226 for practicing the present invention is generator 200 shown in FIG. 13 . The first and second bit lines 224 and 230 are each coupled to a sense amplifier 232 .
In operation, a common voltage is applied to both the memory cell 222 and the reference voltage generator circuit 226 , and the reference voltage generator circuit 226 outputs a reference voltage V ref that is applied to the reference cell 228 . The reference cell 228 produces a reference current I ref that is supplied to the sense amplifier 232 by the second bit line 230 . The memory cell 222 produces a memory current I mem that is supplied to the sense amplifier 232 by the first bit line 230 . The memory current I mem is variable (i.e., has different current magnitudes to represent different logical states) and will be either higher or lower than the reference current I ref depending on a logical state stored in the memory cell 222 . Accordingly, the sense amplifier 232 determines the logical state stored in the memory cell 222 by determining whether the memory current I mem is higher or lower than the reference current I ref and outputs the result as a data signal on line 234 .
In the foregoing specification, the invention is described with reference to specific embodiments thereof, but those skilled in the art will recognize that the invention is not limited thereto. For example, the pass gates described above to generate a reference current can include a PMOS gate using a TCCT based memory cell with its cathode coupled to a V dd array. As another example, although the preceding discussion describes generating a reference current at one-half the current to be read, it is also within the scope of the present invention to generate a reference at any level proportionate to the TCCT based memory cell current. Various features and aspects of the above-described invention may be used individually or jointly. Further, the invention can be utilized in any number of environments and applications beyond those described herein without departing from the broader spirit and scope of the specification. The specification and drawings are, accordingly, to be regarded as illustrative rather than restrictive. | A reference cell produces a reference current that is about half of the current produced by a memory cell. The reference cell is essentially the same as the memory cell with an additional current reduction device that can be a transistor. Adjusting a reference voltage applied to the transistor allows the reference current to be varied. A control circuit to produce the reference voltage includes dedicated memory and reference cells and a feedback circuit that compares the two cells' currents. The feedback circuit applies the reference voltage to the reference cell of the control circuit and adjusts the reference voltage until the current from the reference cell is about half of the current from the memory cell. The reference voltage is then applied to other reference cells in a memory array. | 6 |
TECHNICAL FIELD
[0001] The present disclosure relates to compositions useful for maintaining the clean impression of a carpet (that is, its scent and appearance) over an extended time despite occurrences that might damage the carpet surface. The composition, which includes an antimicrobial agent, an enzyme inhibitor, and, optionally, an aldehyde-containing aroma compound, can be used by a consumer to remove contaminants from the carpet and to prevent the odor associated with the decomposition of present and future contamination. Specifically, the composition has been shown effective in neutralizing odors associated with the decomposition of organic materials (such as urine or food spills) by absorbing and/or neutralizing the odor-generating source. A pre-treatment composition and methods for using are also disclosed.
BACKGROUND
[0002] “Contamination”, as defined herein, means the unintentional introduction of undesirable and potentially damaging materials onto a carpet surface, specifically including contaminants such as human or animal waste, food spills, and vomit. “Carpet”, as used herein, refers to a textile floor covering having a plurality of pile fibers and a backing surface, and specifically includes broadloom carpeting, area rugs, and mats.
[0003] People tasked with maintaining carpet in commercial and/or residential settings have often experienced problems with removal of odors associated with organic contamination. Such contamination may occur, for example, when food or drink is spilled onto a carpet surface. Contamination also occurs if an individual vomits on the carpet. Yet a third source of contamination is from human or animal urine, as may occur in homes with indoor pets or in health care or nursing facilities that care for patients suffering from incontinence.
[0004] In situations such as those described above, the contamination reaches the carpet surface and either remains on the surface or is absorbed by the pile fibers. The contaminant, which may or may not have foul odors inherent in the contaminant, will begin to decompose over time, if not removed. The decomposition process, in most instances, generates odor molecules as the organic contaminant breaks down. Clearly, this odor generation is problematic for maintaining a pleasant-smelling environment. Urine odors, for example, are particularly difficult to mask or neutralize.
[0005] There are several approaches used by those tasked with maintaining clean-appearing carpet. One approach is to clean the affected area with water and/or detergent. Another approach is to clean the affected area and then apply a fragrance-carrying compound to the surface or the air to mask the odor. These approaches have not been wholly sufficient or successful.
[0006] One reason that these approaches fail is that the cleaning technique is ineffective at removing the contaminant. Because the cleaning technique is ineffective at removing all of the contaminant, some source material remains in the carpet. As this source material decomposes, odor molecules emanate from the source, resulting in an undesirable situation for those in proximity to the contamination. Furthermore, the cleaning process leaves a residual amount of cleaning compositions in the carpet. Conventional wisdom holds that any remaining detergent or surfactant left in the carpet pile will “attract” dirt, resulting in a dirty or dingy-looking appearance over time.
[0007] A second reason that these approaches fail is because, rather than eliminating odors, they only mask the odors with fragrance. When an individual has completed his cleaning efforts, he may choose to use a scented powder or spray to restore the fresh scent of the carpet. Fragrances associated with scented powders or sprays provide temporary pleasant smells to the room in which they are used, but the malodors are again noticeable when the fragrance disperses.
[0008] Finally, using hot water or steam extraction to clean the carpet raises several issues. One issue is the availability, efficiency, and expense of the cleaning equipment. In some instances, individuals turn to professional cleaning services to perform this type of carpet maintenance. Another issue is the amount of water that is in contact with the carpet and how long it takes to dry. Water can seep through the carpet pile and into the carpet padding and/or sub-flooring, which then becomes susceptible to damage from mildew. Deterioration of the padding and sub-flooring can also be an issue. Hot water or steam extraction also leaves residual amounts of detergent or surfactant in the carpet pile, leading to problems that have been previously discussed.
[0009] The present disclosure addresses the shortcomings of the previous approaches. The present composition provides a cleaning composition that allows the contaminant to be removed before it breaks down and generates odor. The residual amount of composition that remains after cleaning is useful in preventing deterioration of future contaminants that contact the carpet and in aiding removal of future contaminants.
SUMMARY
[0010] The cleaning composition described herein includes an antimicrobial agent, an enzyme inhibitor, and, optionally, an aldehyde-containing aroma. The present composition is applied as a liquid, preferably in conjunction with a powder cleaning composition. More preferably, the pile of the carpet has also been treated with a treatment composition comprising an antimicrobial agent, an enzyme inhibitor, and, optionally, an odor-absorbing compound. Most preferably, the carpet to which the composition is applied has a liquid barrier layer between the pile and the backing.
DETAILED DESCRIPTION
[0011] The cleaning composition is used to maintain the fresh appearance and scent of clean carpet. The composition is preferably used on a periodic frequency, such as once a month or, more preferably, once every two weeks, to prevent the generation of odor from decomposition of organic contaminants. The cleaning composition can be used in a spray, in a carpet shampoo, as a liquid charge to a powder cleaning composition, and as a cleaning solution for water or steam extracting equipment.
[0012] The treatment composition is preferably applied to the pile layer of the carpet during manufacture, by application techniques such as impregnation, coating, foam coating, spraying, or the like. The treatment composition could also be incorporated in the barrier layer or backing layer of the carpet. The treatment composition includes an antimicrobial agent, an enzyme inhibitor, and, optionally, an odor-absorbing compound.
[0013] In one spray embodiment of the cleaning composition and the treatment composition, an exemplary relative proportion of components is as follows:
(a) from between 0.01% to about 10% by weight of an antimicrobial agent; (b) from between 0.05% to about 10% by weight of an enzyme inhibitor; (c) from between 0% to about 10% by weight of odor-absorbing compound; (d) from between 0% to about 7% by weight of an aldehyde-containing aroma; and (e) the percentage by weight of water is such that the total is 100%.
[0019] In one embodiment where a carrier powder is used, an exemplary relative proportion of components is as follows:
(a) from between 0.01% to about 10% by weight of an antimicrobial agent; (b) from between 0.05% to about 10% by weight of an enzyme inhibitor; (c) from between 0% to about 10% by weight of odor-absorbing compound; (d) from between 0% to about 7% by weight of an aldehyde-containing aroma; (e) from between 10% to about 50% by weight of water; and (f) the percentage by weight of powder is such that the total is 100%.
[0026] It should also be noted that some compounds as are useful herein perform dual functions. For example, some antimicrobial agents (such as 2-bromo-2-nitro-1,3 propanedial) also act as enzyme inhibitors. Likewise, some odor-absorbing compounds (such as zinc ricinoleate) also act as enzyme inhibitors. It should also be noted that, although one compound may perform two functions, a synergistic effect is observed from the use of different compounds and, therefore, at least two different compounds are preferably used as the antimicrobial agent and the enzyme inhibitor.
[0027] The cleaning composition and the treatment composition contain an antimicrobial agent. The antimicrobial agent acts as a preservative and allows the contaminant to be removed (for example, during regular cleaning or maintenance) before the contaminant decomposes and generates odor. The antimicrobial component includes any organic or inorganic compound that effectively controls or inhibits the growth of odor-causing microorganisms, such as bacteria and fungus. Examples of such materials include silver zirconium phosphate, zinc oxide, and polyhexamethylene biguanide. Certain alcohols also are useful for this purpose.
[0028] Preferably, the antimicrobial agent is a formaldehyde-donor antimicrobial, such as N,N′-dimethylol 5,5-dimethyl hydantoin, N-methylol 5,5-dimethyl hydantoin, imidazolidinyl urea, cationic quaternary ammonium salt, sodium/potassium sorbate, sorbic acid, and grapefruit seed extract. Aldehyde-based antimicrobial agents, such as glutaraldehyde, may also be used. It has been found that aldehyde-donor antimicrobials are most effective at eliminating microbes and preventing contaminant decomposition that leads to unpleasant odors, especially those odors associated with urine decomposition. Metal salts are also effective for this purpose, but are less preferred because of their potential to adversely affect the carpet color and their deleterious environmental effects.
[0029] The cleaning composition and the treatment composition also include an enzyme inhibitor. Enzyme inhibitors, such as urease inhibitors useful for controlling ammonia generation from urine contamination, are desirable. Enzyme inhibitors include organic and inorganic salts of zinc, copper, zirconium, aluminum, silver, and tin, as well as organic compounds such as aldehydes (e.g., p-hydroxybenzyl aldehyde) and quaternary ammonium compounds. Urease inhibitors include (a) salts or complexes containing silver ions, zinc ions, or copper ions, (b) boric acids and borates, (c) salt of citric acid, (d) sorbic acid and its salt, (e) aldehydes, (f) bromo-nitro organic compounds, and (g) phophoamide compounds. Because of concern over the use of metal salts, bromo-nitro compounds and phosphoamide compounds are preferably used as enzyme inhibitors.
[0030] An odor-absorbing compound may be included in the treatment composition. The odor-absorbing compound is selected from activated carbon, zeolites, zinc oxide, cyclodextrin, and zinc ricinoleate. The preferred odor-absorbing compounds are zinc ricinoleate and cyclodextrin.
[0031] An aldehyde-containing aroma is preferred as an optional fragrance component in the cleaning composition. Examples of preferred fragrances include citral, cinnamic aldehyde, hexyl cinnamic aldehyde, benzyl aldehyde, benzyl salicylate, amyl cinnamic aldehyde, and vanillin. The most preferred of these is hexyl cinnamic aldehyde, which is commonly used to create a “fresh” scent in many consumer products, such as fabric softener.
[0032] Also optionally included in the cleaning composition are surfactants that enhance cleaning properties. Useful surfactants are ones that do not discolor the carpet, but that provide emulsifying properties for the other components in the cleaning composition.
[0033] In the treatment composition, the antimicrobial agent, the enzyme inhibitor, and the optional odor-absorbing compound are prepared for application to the carpet by combining the components with an amount of water appropriate for the application method. The treatment composition may be applied onto the carpet surface by spraying, by coating, by foam coating, by impregnation or the like. In cases where the treatment composition is applied as a foam, a foam stabilizing agent may also be used. The treatment composition can be applied to a carpet as part of the finishing process at the manufacturing location or as a post-treatment after the carpet has been installed.
[0034] The cleaning composition, as used by persons tasked with carpet cleaning and/or maintenance, can be sprayed directly onto the carpet surface in a concentrated form. Alternatively, and perhaps more preferred, a more dilute liquid cleaning composition is charged onto a cleaning powder composition (that is, sprayed onto the cleaning powder composition until the powder composition is damp). One particularly suitable cleaning powder composition for this purpose is described in U.S. Pat. No. 4,434,067 to Malone, assigned to Milliken Research Corporation and incorporated herein by reference.
[0035] The preferred, patented cleaning powder composition contains a particulate polymeric material, an inorganic salt adjuvant, and an aqueous or organic fluid component. Specifically, the powdered cleaning composition is provided consisting essentially of:
(a) about 100 parts by weight particulate polymeric material having an average particle size of from about 37 to about 105 microns in diameter, an oil absorption value of no less than about 90, and a bulk density of at least about 0.2 g/cc; (b) from about 5 to about 400 parts by weight of an inorganic salt adjuvant having an average particle size of from about 45 to about 60 microns in diameter; and (c) from about 5 to about 400 parts by weight of a fluid consisting essentially of 0 to 100 percent water containing sufficient surfactant to give a surface tension of less than about 40 dynes per centimeter and 100 to 0 percent of organic liquid selected from high boiling hydrocarbon solvents, tetrachloroethylene, methylchloroform, 1,1,2-trichloro-1,2,2,-trifluoroethane, an aliphatic alcohol containing from 1 to about 4 carbon atoms, and mixtures thereof.
[0039] It has been found that this particular compound is highly effective at removing a variety of contaminants from carpet, without creating any of the problems associated with wet cleaning techniques in which the carpet is saturated.
[0040] The following examples are intended to be representative of various embodiments of the present invention.
EXAMPLE 1
[0041] One embodiment of the liquid cleaning composition was created comprising the following ingredients:
(a) as an antimicrobial agent, 5% by weight of sorbic acid, which is particularly effective against fungi- and yeast-containing contaminants; (b) as enzyme inhibitors, 1% by weight of copper sulfate, 1% by weight of salicylic acid, and 0.5% by weight of zinc sulfate; (c) as an odor-absorbing agent (and also as an enzyme inhibitor), 3% by weight of zinc ricinoleate, available as 30% active ingredient from Degussa under the trade name “TEGO SORB 30”; (d) as aroma, 1% by weight of hexyl cinnamic. aldehyde, 1% by weight of cinnamic aldehyde, and 1% by weight of citral; and (e) as solvent, water such that the total percentage equaled 100%.
[0047] The ingredients were combined and used to saturate a 2″ circle of carpet. The carpet was then blotted dry with paper towel such that the carpet circle retained about one gram of the solution. Then, 4 milliliters (mL) of 10% urea and 3 drops of 0.005% urease (type III, purchased from Sigma) were added separately to the treated carpet and to an untreated “control” carpet. Urease is an enzyme that causes urea to decompose and release ammonia, which is responsible for the characteristic pungent smell of urine odor.
[0048] Each carpet samples was sealed in a 250 mL plastic beaker. A small piece of nonwoven fabric impregnated with bromothymol blue indicator water solution was then used to monitor the presence of ammonia in the headspace of each beaker. This indicator solution is light yellow in the absence of ammonia, but turns to dark blue in the presence of ammonia.
[0049] Observations were made 1 hour, 2 hours, and 4 hours after the addition of the urea and urease solutions. After approximately only 10 minutes, the control carpet sample (untreated) showed the presence of ammonia. At no time during the observation period did the treated sample indicate the presence of ammonia. This result indicates that the chemical cleaning compound described above is capable of inhibiting urease activity and preventing ammonia generation from the decomposition of urea.
[0050] Also worth noting, the untreated control sample generated significant ammonia odor in the headspace of the beaker after 2 hours. Although the treated sample generated ammonia odor when left overnight, it is clear that the cleaning composition demonstrated effective human urine odor control properties.
[0051] In comparison, commercially available products such as Fabreze, Syon 5, and Woolite Pet cleaner mask the odor of ammonia, but the presence of ammonia is detectable by this method after less than half an hour on average.
EXAMPLE 2
[0052] An alternate embodiment of the liquid cleaning composition was created comprising the following ingredients:
(a) as an antimicrobial agent, 3% by weight of sodium sorbate and 0.8% of monomethylol dimethyl hydantoin, a formaldehyde-donor antimicrobial agent sold under the trade name “DANTOGUARD 2000” by Lonza, Inc. of Fair Lawn, N.J.; (b) as enzyme inhibitors, 0.3% of citric acid; (c) as an odor-absorbing agent (and also as enzyme inhibitor), 3% by weight of zinc ricinoleate, available as 30% active ingredient from Degussa sold under the trade name “TEGO SORB 30”; (d) as aroma, 1% by weight of hexyl cinnamic aldehyde, 1% by weight of a fragrance blend sold as “Green Downy-type Fragrance H20-type” from Berge'; and (e) as solvent, water such that the total percentage equaled 100%.
[0058] Zinc ricinoleate is effective at absorbing some of the odor associated with urine as a contaminant. The addition of sodium sorbate. and monomethylol dimethyl hydantoin, along with the inclusion of hexyl cinnamic aldehyde fragrance, makes the cleaning composition more effective at eliminating malodors from human urine than that of EXAMPLE 1. (Or “particularly effective” if you don't want to compare the two)
EXAMPLE 3
[0059] A liquid cleaning composition was created similar to that of EXAMPLE 2, which was added to a urea formaldehyde powder having 30% moisture content, thereby creating a damp powder cleaning composition comprising the following ingredients:
(a) as an antimicrobial agent, 3% by weight of sodium sorbate and 0.8% of monomethylol dimethyl hydantoin, a formaldehyde-donor antimicrobial agent sold under the trade name “DANTOGUARD 2000” by Lonza, Inc. of Fair Lawn, N.J.; (b) as enzyme inhibitors, 0.3% of citric acid; (c) as an odor-absorbing agent (and also as enzyme inhibitor), 3% by weight of zinc ricinoleate, available as 30% active ingredient from Degussa sold under the trade name “TEGO SORB 30”; (d) as aroma, 1% by weight of hexyl cinnamic aldehyde, 1% by weight of a fragrance blend sold as “Green Downy-type Fragrance H20-type” from Berge'; (e) 5% by weight of water; and (f) as carrier, urea formaldehyde powder such that the total percentage equaled 100%.
EXAMPLE 4
[0066] Yet another embodiment of the liquid cleaning composition was created comprising the following ingredients:
(a) as an antimicrobial agent, 0.05% by weight of 2-bromo-2-nitro-1,3 propanedial; (b) as an enzyme inhibitor, 0.3% by weight of citric acid; (c) as a surfactant to aid in suspending the components in solution, 2% by weight of “Triton XL80N” sold by Dow Chemical Company; (d) as aroma, 1% by weight of hexyl cinnamic aldehyde; and (e) as solvent, water such that the total percentage equaled 100%.
[0072] This composition completely prevented the generation of detectable ammonia odors when tested according to Test 1 and Test 2, as will be described.
EXAMPLE 5A
[0073] This example was-created as a comparative example for the compositions described in EXAMPLES 5B and 5C. In this composition, the antimicrobial component was purposely omitted. The comparative treatment composition comprised:
(a) as an odor-absorbing agent (and also as enzyme inhibitor), 3% by weight of zinc ricinoleate, available as 30% active ingredient from Degussa sold under the trade name “TEGO SORB 30”; (b) as an enzyme inhibitor, 0.3% by weight of citric acid; (c) as solvent, water such that the total percentage equaled 100%.
EXAMPLE 5B
[0077] This example describes a first embodiment of a treatment composition useful for application to the carpet surface during manufacturing or after installation. The treatment composition comprises:
(a) as antimicrobial compound (and also an enzyme inhibitor), 2-bromo-2-nitro-1,3 propanedial; (b) as an enzyme inhibitor, 0.3% by weight of citric acid; (c) as solvent, water such that the total percentage equaled 100%.
EXAMPLE 5C
[0081] This example describes a second embodiment of a treatment composition useful for application to the carpet surface during manufacturing or after installation. The treatment composition comprises:
(a) as antimicrobial compound (and also an enzyme inhibitor), 0.02% by weight of 2-bromo-2-nitro-1,3 propanedial; (b) as an antimicrobial compound, 0.5% by weight of of monomethylol dimethyl hydantoin, a formaldehyde-donor antimicrobial agent sold under the trade name “DANTOGUARD 2000” by Lonza, Inc. of Fair Lawn, N.J.; (c) as an enzyme inhibitor, 0.3% by weight of citric acid; and (d) as solvent, water such that the total percentage equaled 100%. 20 mL of EXAMPLES 5A, 5B, and 5C were allowed to soak into 4″×4″ square carpet samples. The carpet samples were dried at about 110° C. for 20 minutes to evaporate the water, leaving (on EXAMPLES 5B and 5C) a thin coating of antimicrobial compound and enzyme inhibitor on the yarns of the carpet pile. Other trials in which samples were dried at about 300° F. and at about 370° F. showed decrease efficacy, but the samples were still functional.
[0086] When tested using Test 1, as will be described, the three carpet treatments prevented the generation of detectable amounts of ammonia.
[0087] When tested using Test 2, only EXAMPLES 5B and 5C were successful at preventing the generation of odor for one month, thus supporting the hypothesis that the combination of an antimicrobial component and an enzyme-inhibiting component is most effective.
Testing of Exemplary Embodiments
[0088] The following tests were conducted to demonstrate the effectiveness of the present cleaning composition at controlling human urine odor.
Test 1: Urease Inhibition Test
[0089] Three carpet samples, having been cleaned using different methods, were. used in this test. All of the samples were 15″×15″ carpet squares, constructed with a liquid barrier layer between the pile face yarns and the foam backing and a silver zirconium phosphate antimicrobial agent in the back-coating.
[0090] Sample A was cleaned using the composition of Examples 2 and 3 described above. The carpet was sprayed with the composition of Example 2, in a fine mist. The powder composition of Example 3 was then brushed into the carpet. Then, the carpet was vacuumed, using a commercially available vacuum cleaner.
[0091] Sample B was cleaned using a commercially available liquid cleaning solution for carpet, which includes as its active ingredient an Australian tea tree extract. The carpet was saturated with the cleaning solution and then subjected to cleaning with an extraction-type vacuum cleaner.
[0092] Sample C was cleaned using only water with an extraction-type vacuum cleaner. No cleaning compositions were used.
[0093] The test procedure will now be described. For each sample, 40 ml of fresh human urine was applied to the carpet pile after cleaning. Each sample was sealed inside a 2 mil thick plastic bag to prevent evaporation of moisture and odors. The samples were stored inside the sealed bags for ten days, after which human judges were asked to evaluate, on a scale of 1 to 10, the odor in the headspace of the bag. Using this scale, 1 indicated the worst odor and 10 indicated the most pleasant odor.
[0094] After being assessed by the judges, the carpet samples were removed from the bags and cleaned using the same procedures as described above. Another 40 mL of fresh human urine was applied to each carpet sample. Each sample was then placed in a clean 2 mil thick plastic bag, where the sample remained for a total of 5 days. At the end of the 5 days, the human judges again evaluated the odor in the headspace of the bags using the same 1 to 10 scale. The pH of the headspace was also evaluated, using a pH indicator strip moist with distilled water, to detect the presence of ammonia (pH values higher than 7 indicate the presence of ammonia).
[0095] TABLE 1 shows the results of TEST 1: Urease Inhibition Test.
TABLE 1 Results of Urease Inhibition Test Sample ID Cleaning Method Headspace pH Odor Rating A Cleaning Composition + 5 8 Vaccum B Commercially Available 9 2 Cleaning Liquid + Extraction C Water + Extraction 10 1
[0096] The results above indicate that the present cleaning composition and composition are effective in controlling human urine odors on carpet and in preventing ammonia generation.
Test 2: Odor Removal Test
[0097] In this experiment, human urine was collected and stored for 10 days in a sealed bottle. Strong ammonia and other odors developed. 10 mL of the aged urine was applied to an 8″×8″ carpet sample, and the carpet was allowed to sit for 2 hours before being cleaned with the present liquid cleaning composition as used with the powder cleaning composition described herein. The powder cleaning composition was dampened with the present liquid cleaning composition and then sprinkled onto the carpet. The cleaning composition was brushed into the carpet and then removed by vacuuming.
[0098] The odor of the carpet sample was evaluated following cleaning and two weeks after cleaning to determine whether the cleaning composition was effective at removing odor. No ammonia or other offensive odors were detected at either time.
[0099] Having been evaluated, the recently cleaned sample was subjected to another round of testing, in which an additional 10 mL of human urine were added to the carpet. The carpet sample was then placed into a sealed plastic bag to prevent evaporation of the moisture and dispersion of any generated odors.
[0100] After ten days storage at room temperature, the sample was evaluated to determine whether the residual cleaning composition remaining in the carpet was effective at preventing the generation. of odors from later-applied contaminants. No ammonia or other odors were detected, proving that the cleaning composition was effective in preventing the generation of odors.
Conclusions
[0101] The tests conducted indicate that the compositions described herein, which comprise an antimicrobial compound and an enzyme inhibitor, are effective at removing existing contaminants and their odors from carpet, at preventing recurrence of odors from degeneration of later applied contaminants, and at maintaining the desired appearance and smell of carpet cleaned according to the teachings herein. For these reasons, the present compositions represent a useful advance over the prior art. | The present disclosure relates to compositions useful for maintaining the clean impression of a carpet (that is, its scent and appearance) over an extended time despite occurrences that might damage the carpet surface. The composition, which includes an antimicrobial agent, an enzyme inhibitor, and, optionally, an aldehyde-containing aroma, can be used by a consumer to remove contaminants from the carpet and to prevent the odor associated with the decomposition of future contamination. Specifically, the composition has been shown effective in neutralizing odors associated with the decomposition of organic materials (such as urine or food spills) by absorbing and/or neutralizing the odor-generating source. A pre-treatment composition and methods for using are also disclosed. | 2 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of International Application No. PCT/GB2009/000520 filed on Feb. 25, 2009, which claims the benefit of GB 0804043.8, filed Mar. 4, 2008. The disclosures of the above applications are incorporated herein by reference.
FIELD
The present disclosure relates to a termination tool and corresponding male and female connectors.
BACKGROUND
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Termination tools exist in many different forms, with the desirable characteristics including portability, ease of assembly, ease of use and reliable termination of the connector to communication wires.
US Patent Publication No. 2006/0230608 describes a termination tool for use with network jack plugs and sockets such as CAT 5e, CAT 6, etc. The tool is designed to work in two distinct stages. An electrical connector wire arrangement manifold is prepared by inserting wires into the relevant connector slots on said wire arrangement manifold and placing the cap into a cavity on one side of the tool. Adjacent to said cavity are cutting means, mounted such that upon actuation of a trigger mechanism the cutting means are urged astride the prepared wire arrangement manifold, severing any excess wires protruding thereon and driving the wires securely into the connector slots. A second, separate cavity is provided on the other side of the tool into which the trimmed wire arrangement manifold and a jack housing are inserted adjacent each other. Actuation of the trigger mechanism urges a ram against the wire arrangement manifold, pressing it into engagement with the jack housing, whereupon the wires in the wire arrangement manifold make electrical contact with connection terminals in the jack housing, thus securing the wire arrangement manifold within the jack housing, and terminating wire arrangement manifold and housing sections of the electrical connector.
However, this device suffers from the disadvantage of requiring two distinct operations to be performed; the trimming of wires protruding from the prepared wire arrangement manifold and then the repositioning of said wire arrangement manifold such that a ram may be used to urge the wire arrangement manifold into engagement with a jack housing.
SUMMARY
According to the present disclosure there is provided a termination tool for terminating multiple wires to a two part electrical connector assembly composed of a wire arrangement manifold and a jack housing, the termination tool comprising a main tool body having a termination housing provided thereon including a first cavity, a second cavity and a passage extending between the first and second cavities, the first cavity having an open side to receive and being shaped to removably retain the wire arrangement manifold, the second cavity having an open side to receive and being shaped to removably retain the jack housing, and the passage being sized to allow, in use, the wire arrangement manifold pass therethrough from the first cavity to the second cavity and having cutting means provided on opposing side of its end proximate to the first cavity, the termination tool further comprising a ram aligned with the passage and actuatable to move between a retracted position in which the ram is withdrawn from the first cavity and a second position in which the ram extends through the passage so as, in use, to press the wire arrangement manifold from the first cavity, through the passage and into engagement with the jack housing located in the second cavity, the cutting means severing any overhanging wire tails from the sides of the wire arrangement manifold as it enters the passage.
A termination tool is thus provided where corresponding male and female connectors are arranged such that in one motion the tool is used to cut multiple electrical connector wires and then terminate wire arrangement manifold and housing sections of an electrical connector. A termination tool in accordance with the present disclosure has the advantage that the whole termination operation is performed in a single operation, increasing efficiency.
In one form, the first cavity is of complementary shape to and a close tolerance fit with the wire arrangement manifold such that, in use, the wire arrangement manifold is constrained against lateral movement in the first cavity. Similarly, the second cavity is of complementary shape to and a close tolerance fit with the jack housing such that, in use, the jack housing is constrained against lateral movement in the second cavity. In this way, the wire arrangement manifold and jack housing are accurately aligned with each other so as to ensure reliable termination upon actuation of the tool.
In one form, the first cavity includes a groove in each side surface thereof adjacent the cutting means at the mouth of the passage in which, in use, tails of wires inserted into the wire arrangement manifold are received so as to align them for trimming by the cutting means upon operation of the tool. This has the further advantage that the longitudinally asymmetric configuration of the grooves prevents insertion of the wire arrangement manifold into the first cavity in the wrong orientation since the wire tails will then not align with the grooves and hence the close tolerance fit of the wire arrangement manifold in the first cavity will prevent entry of the wire arrangement manifold into the first cavity.
The cutting means, in one form, comprises a pair of blades, one on either side of the mouth of the passage. Further advantageously, the position of the cutting means is related to the thickness and spacing of wires in the wire arrangement manifold, such that, in use, the leading edge of the cutting means engages with, and subsequently severs, the wire tails sequentially, rather than simultaneously. This has the advantage of reducing the force required to operate the tool and therefore, for example, reducing a required actuator pivot length or the like. The sequential severing of the wire tails could be achieved by offsetting the cutting means either side of the mouth of the passage relative to each other, by inclining the cutting edge of the cutting means relative to the direction of movement of the wire arrangement manifold or by a combination of the two. Preferably the wire tails are severed in pairs and further advantageously the cutting means is positioned such that the severance of a pair of wire tails by the cutting means is completed before the next pair of wire tails is subsequently engaged by the leading edge of the cutting means. The width of the passage is also advantageously equal in width to the first cavity.
The passage may include a longitudinally extending rib on the top of each side, which reduces the width of the passage at the top and thereby prevents the wire arrangement manifold from being removed from the passage during operation of the tool.
In one form, the second cavity includes one of a projection and a recess in a side thereof, in particular the side opposite the passage, and the jack housing includes a complementary other of a projection and a recess which aligns with the one of the projection and the recess when the jack housing is correctly oriented with respect to the second housing. This has the advantage that it ensures proper alignment of the jack housing upon insertion since it will be prevented from entering the second cavity if wrongly oriented. In a preferred embodiment, the jack housing includes a tab, which engages in a slot, which extends from the open side of the second cavity.
The open sides of the first and second cavities are on the same side of the tool in one form of the present disclosure.
The depth of the first cavity is preferably such that when the wire arrangement manifold is fully inserted therein, it aligns with the passage. Similarly, the depth of the second cavity is preferably such that, when the jack housing is fully inserted therein, an opening in the jack housing in which the wire arrangement manifold engages for effecting termination is aligned with and facing the passage.
In one form, the tool is hand operated, including trigger which is connected to the ram so as to effect longitudinal movement of the ram from its retracted position to its extended position. A ratchet mechanism is advantageously integrated with the trigger mechanism, which operates to prevent retraction of the ram, once operative movement has commenced, until the ram has reached its fully extended position. This has the advantage that it ensures that proper termination occurs between the wire arrangement manifold and the jack housing. Other means may also be provided which prevents operation of the trigger until a wire arrangement manifold has been properly inserted into the first cavity and a jack housing has been properly inserted into the second cavity.
The trigger may be spring-loaded to effect return of the ram to its retracted position once the termination stroke has been completed.
The present disclosure further provides a wire arrangement manifold for use with a termination tool according to the disclosure, comprising a body having an end surface with an opening therein through which, in use, a cable formed of a plurality of separate wires is insertable, a front face having a plurality of notches formed therein proximate to at least one side of the wire arrangement manifold, each notch size to retain one of the wires of the cable therein, and a passage extending from the opening in the end surface to the front face for channelling the wires to the notches.
In one form, the notches in the front face of the wire arrangement manifold are arranged in two rows, one extending along each side of the body, with the notches being equi-spaced along the body. In particular, the end housing has eight notches arranged in two rows of four.
The body in one form is rectangular in shape, at least when viewed in the direction of the front face. The opening in the end face is preferably open to the back of the end housing, the passage taking the form of a through opening which extends from the back to the front face of the body.
The present disclosure still further provides a jack housing for matingly engaging with the wire arrangement manifold of the disclosure, the jack housing comprising a body having a socket formed in a front end therein containing a plurality of contacts, an opening in a top side of the body and a plurality of termination jaws upstanding from the bottom of the opening, each termination jaw being electrically connected to an associated one of the contacts, the opening being of complementary size and shape to the wire arrangement manifold such that, in use, the wire arrangement manifold is insertable into the opening from the top thereof such that each wire located in one of the notches in the wire arrangement manifold engages between one of termination jaws, effecting electrical contact therewith.
In one form, the back wall of the opening in the jack housing has a slot formed therein extending from the top edge, the cable extending from the wire arrangement manifold, in use, being received in the slot as the wire arrangement manifold engages in the opening.
The bottom of the body advantageously has a guide tab thereon of narrower width than the main body, which, in use, aligns with and engages in a complementary shaped recess formed in the second cavity when the jack housing is correctly oriented with respect to the second cavity and prevents entry of the jack housing into the second cavity in the wrong orientation. The guide tab is advantageously formed as a mounted hook for latching the jack housing in place in a patch panel, wall mounting or the like.
In one form, the opening includes eight termination jaws arranged in two rows of four to complement the arrangement of the notches in the wire arrangement manifold, each jaw being composed of a pair of metal prongs with a space between them which narrows towards the base of the opening such that as a wire is pressed therebetween, the jaws progressively cut through the insulation on the wire and make electrical contact with the core of the wire.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
DRAWINGS
In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:
FIG. 1 is a side view of an apparatus according to the invention, showing the insertion of a jack housing and wire arrangement manifold;
FIG. 2 is an exploded perspective view of the apparatus of FIG. 1 ;
FIGS. 3( a ), 3 ( b ) and 3 ( c ) are partial perspective views of the apparatus of FIG. 1 , showing extension of the ram;
FIGS. 4( a ) and ( b ) are overhead views of the first and second cavities at retracted and extended positions of the ram, showing the shape of each cavity;
FIG. 5 is a perspective view of the apparatus of FIG. 1 , showing the apparatus fully engaged;
FIG. 6 is a perspective view of the apparatus of FIG. 1 , showing retraction of the ram and subsequent removal of the electrical connection assembly;
FIG. 7 is a perspective view of the jack housing and wire arrangement manifold;
FIG. 8 is a perspective view of the wire arrangement manifold cover;
FIG. 9 is a perspective view of the assembled jack housing, wire arrangement manifold and cover; and
FIG. 10 is a perspective view of the assembled jack housing, wire arrangement manifold and cover showing the jack socket.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
DETAILED DESCRIPTION
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.
Referring first to FIGS. 1 , 2 and 3 , there is shown a hand-held termination tool 100 for effecting automated termination of an wire arrangement manifold 101 into a jack housing 102 for providing electrical connection between wires 103 mounted in the wire arrangement manifold 101 and contact jaws 104 provided in the jack housing 102 . The termination tool 100 has a main tool body 105 with a handle 106 fast with the body 105 and a trigger 107 pivotally attached to the body 105 and operably moveable towards the handle 106 in order to effect movement of a ram 108 as described hereinafter. Biasing means such as a spring (not shown) is connected to the trigger 107 , which urges the trigger 107 away from the handle 106 . Attached to the front portion of the main tool body 105 is a termination housing 109 having a pair of spaced apart cavities 110 and 111 formed therein, each of which extends to the top 109 a of the termination housing 109 , and a passage 112 which extends between the first and second cavities 110 , 111 so as to allow movement of an element from the first cavity 110 to the second cavity 111 as described below.
As shown in FIG. 3 c , the first cavity 110 is generally rectangular in cross section and is sized to enable the wire arrangement manifold 101 to be engaged end on into the cavity from the top side 109 a of the housing 109 with a close tolerance fit such that the wire arrangement manifold 101 is restrained from lateral movement within the first cavity 110 . The first cavity 110 furthermore includes a pair of side wing slots 113 , one formed in each side wall of the cavity proximate to the end where it meets the passage 112 , each slot 113 extending from the top side 109 a of the housing 109 substantially the full depth of the first cavity 110 .
The second cavity 111 is similarly generally rectangular in cross section but is of a larger cross section and depth compared with the first cavity 110 to accommodate the larger size of the jack housing 102 . As with the first cavity 110 , the cross section of the second cavity 111 is sized to enable the jack housing 102 to be slid end on into the second cavity 111 from the top side 109 a of the housing 109 , there being a close tolerance fit between the jack housing 102 and the sides of the second cavity 111 so as to prevent lateral movement of the jack housing 102 and hence accurately locate the jack housing 102 laterally therein. The depth of the first and second cavities 110 , 111 are furthermore set so that when the wire arrangement manifold 101 and jack housing 102 are fully inserted into their respective cavities, they are accurately longitudinally located relative to each other as well as relative to the passage 112 .
The passage 112 which extends between the two cavities 110 , 111 is sized laterally to be a close tolerance fit with the wire arrangement manifold 101 so that the wire arrangement manifold 101 , once fully inserted into the first cavity 110 , can move longitudinally through the passage 112 and into the second cavity 111 and has the same depth as the first cavity 110 . A cutting blade 114 is located on each side of the mouth of the passage 112 at the intersection with the first cavity 110 in alignment with the wing slots 113 , the blades 114 extending substantially the entire depth of the passage 112 and being laterally spaced apart such that the wire arrangement manifold 101 is a close tolerance fit therebetween. The cutting blades 114 are cutting means for cutting wires.
Although not shown in the illustrated embodiment, the passage 112 may optionally have a rib extending longitudinally along each side proximate to the top, which forms a constriction in the cross section, preventing the wire arrangement manifold 101 from moving vertically as it moves through the passage 112 .
Ram 108 is mounted in the main body 105 in alignment with the passage 112 and is pivotally connected to the end of the trigger 107 so that when the trigger 107 is operated, the ram 108 is moved forwards into the termination housing 109 from a retracted position (shown in FIG. 2 ) in which it is fully withdrawn into the main body 105 and out of the first cavity 110 , and an extended position in which it is moved longitudinally through the first cavity 110 and into the passage 112 , projecting into the second cavity 111 as shown in FIG. 4 b . Guides 115 channel the path of the ram 108 so as to constrain it to move only in the longitudinal direction. The trigger 107 also includes a ratchet mechanism 120 , which controls the forward movement of the ram 108 and prevents it from being withdrawn back into its retracted position until it has reached its fully extended position. Such mechanisms are within the practical knowledge of the skilled person and will not, therefore, be described here in greater detail.
The wire arrangement manifold 101 , shown in more detail in FIG. 7 comprises a generally rectangular body 101 a having a through opening 101 b therein which links to an opening 101 c in the rear end of the body. A series of notches 116 are formed in the opposing sidewalls extending from the bottom edge thereof, in the illustrated embodiment four equi-spaced notches 116 in each sidewall, in each of which is engageable a single wire of a cable bundle. As shown in FIG. 2 , the cable 117 is fed through the rear opening 101 c and the wires 103 are fed through the opening 101 b to the bottom of the wire arrangement manifold 101 . Each wire 103 is then located in its allotted notch 116 , identified by colour coding or the like provided on each side of the body 101 a in alignment with the notches 116 , with the free end of the wire 103 extending laterally from the sides of the wire arrangement manifold 101 .
The jack housing 102 , also shown in FIG. 7 , again comprises a generally rectangular body 102 a having a jack socket 102 b in its front face (shown in FIG. 10 ) with a plurality, in particular eight contacts therein. The top 102 c of the body 102 a has a rectangular opening 102 d formed therein in the bottom 102 e of which are upstanding a plurality, in particular eight, contact jaws 104 , each of which is electrically connected to one of the contacts of the jack socket 102 b . The jaws 104 are of the type known in the art which are self-terminating with an inserted wire, that is they automatically cut through any insulation on an appropriately sized wire pressed between the jaws so as to make electrical contact with the inner core of the wire, and they are arranged in two spaced apart rows of four jaws corresponding to the pattern of the notches 116 in the wire arrangement manifold 101 . The opening 102 d is bound by opposing sidewalls; a front wall and a rear wall, which has a through opening, formed therein which extends to the top of the opening 102 d . The opening 102 d is sized such that the wire arrangement manifold 101 is a press fit therein through the open top of the opening 102 d with the tail of a cable which extends from the wire arrangement manifold 101 locating in the through opening in the rear wall of the opening 102 d , each notch 116 in the wire arrangement manifold 101 aligning the wire 103 located therein with one of the jaws 104 so that as the wire arrangement manifold 101 is pressed fully into the opening 102 d , each wire 103 engages in its associated jaw 104 and makes electrical contact therewith.
A cover 121 , as shown in FIGS. 8 and 9 , fits over the wire arrangement manifold 101 and secures into the jack housing 102 at the opening 102 d so as to protect the terminated wires 103 and provide an enclosed casing in which the wire arrangement manifold 101 is held. A recess 102 f surrounding the opening 102 d in the jack housing 102 is sized such that the cover 121 is a press fit therein. An opening 121 a in the cover 121 allows the cable 117 to be fed through.
The tools operates as follows:
The cable 117 is fed through the opening 121 a of the cover 121 and then through the rear opening 101 c of the wire arrangement manifold 101 . The wires 103 are then inserted through the through opening 101 b and each wire 103 pressed into one of the notches 116 with the excess wire 103 overhanging the sides of the wire arrangement manifold 101 . The jack housing 102 is then inserted into the second cavity 111 with the rectangular opening 102 d in the top thereof facing the first cavity 110 . A mounted hook 118 is provided on the bottom of the jack housing 102 which has a smaller width than the main body 105 and a complementary channel 119 is formed on the side of the second cavity 111 remote from the first cavity 110 such that when the jack housing 102 is inserted into the second cavity 111 in the correct orientation the mounted hook 118 engages in the channel 119 , allowing the jack housing 102 to be fully inserted into the second cavity 111 , whereas if the jack housing 102 is presented to the termination housing 109 in the wrong orientation, the differing width of the second cavity 111 and guide channel 119 prevents the jack housing 102 from being inserted.
The wire arrangement manifold 101 is then inserted into the first cavity 110 with the bottom 101 d facing the second cavity 111 so that the notches 116 open towards the second cavity 111 . When the wire arrangement manifold 101 is aligned with the first cavity 110 in the correct orientation as shown in FIG. 3 a , the projecting tails of the wires 103 align with the wings slots 113 , providing the extra space to allow the wire arrangement manifold 101 to slide into the first cavity 110 . On the other hand, if the wire arrangement manifold 101 is presented to the first cavity 110 in the wrong orientation, the offset configuration of the notches 116 means that the wire tails 103 do not align with the wing slots 113 , so that the close tolerance fit between the wire arrangement manifold 101 and the first cavity 110 prevents the wire arrangement manifold 101 from entering the first cavity 110 .
Once both the wire arrangement manifold 101 and the jack housing 102 are fully inserted into their respective cavities 110 , 111 the trigger 107 is pressed towards the handle 106 , moving the ram 108 towards the first cavity 110 , engaging the wire arrangement manifold 101 and pressing it towards the passage 112 . As the wire arrangement manifold 101 is engaged by the ram 108 , the tails of the wires 103 overhanging either side of the wire arrangement manifold 101 are pressed against the cutting blades 114 , severing the wires 103 flush with the sides of the wire arrangement manifold 101 and freeing the wire arrangement manifold 101 to move through the passage 112 and into engagement with the aligned rectangular opening 102 d in the top facing of the jack housing 102 as shown in FIG. 3 b . Although not shown in the illustrated embodiment the cutting surfaces of the cutting blades 114 are angled with respect to the vertically aligned wires 103 such that they engage with, and subsequently cut, the wires sequentially. The wires 103 opposing each other on either side on the wire arrangement manifold 101 are severed in pairs—the cut of each pair of wires 103 is completed before the leading edge of the cutting blade 114 engages with and then cuts the next pair.
As the ram 108 reaches its fully extended position, the wire arrangement manifold 101 is pressed fully into the jack housing 102 shown in FIG. 3 c , and the wires 103 mounted in the notches 116 are pressed into engagement with the aligned contact jaws 104 upstanding from the base 102 e of the opening 102 d in the jack housing 102 , making electrical contacts therewith. The ratchet mechanism 120 prevents the trigger 107 from being released to withdraw the ram 108 back to its retracted position until it has reached its fully extended position, thereby ensuring that the electrical connections are properly made. Once the fully extended position is reached, release of the trigger 107 causes it to move away from the handle 106 under the action of the biasing means, withdrawing the ram 108 from the cavities 110 , 111 and releasing the jack housing 102 with wire arrangement manifold 101 fastened thereto to be withdrawn from the second cavity 111 . The severed tails of the wires 103 are free to drop out of the wing slots 113 and the tool is ready for the next termination operation. Finally, on removal of the terminated wire arrangement manifold 101 and jack housing 102 from the termination housing 109 , the cover 121 is manually pressed into the recess 102 f in the jack housing 102 so as to enclose the terminated wires 103 .
Thus, the hand-held tool can be used to achieve a terminated connector assembly by the action of one continuous motion; trimming the connector wires and terminating connector halves, without the need to stop to reposition components.
It should be noted that the disclosure is not limited to the embodiment described and illustrated as examples. A large variety of modifications have been described and more are part of the knowledge of the person skilled in the art. These and further modifications as well as any replacement by technical equivalents may be added to the description and figures, without leaving the scope of the protection of the disclosure and of the present patent. | A termination tool for terminating multiple wires to a two part electrical connector assembly composed of a wire arrangement manifold and a jack housing is provided by the present disclosure. The termination tool includes a main tool body having a termination housing provided thereon including a first cavity, a second cavity and a passage extending between the first and second cavities. The first cavity has an open side to receive and is shaped to removably retain a wire arrangement manifold, the second cavity having an open side to receive and being shaped to removably retain a jack housing, and the passage being sized to allow, in use, the wire arrangement manifold to pass therethrough from the first cavity to the second cavity and having cutting means provided on opposing sides of its end proximate to the first cavity. | 8 |
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a continuation application of U.S. patent application Ser. No. 12/177,530, filed Jul. 22, 2008, and titled “Multi-Vendor Multi-Loyalty Currency Program”, which claims priority to Prov. U.S. Pat. App. Ser. No. 60/951,457, filed Jul. 23, 2007, and titled “Multi-Vendor Loyalty Program”, the entire disclosures of which applications are hereby incorporated herein by reference.
FIELD
Various implementations, and combinations thereof, are related to payment processing programs, more particularly to loyalty programs, and most particularly to a loyalty program within a payment processing system having multiple vendors.
BACKGROUND
Loyalty programs provide consumers with incentives to shop at certain loyalty program participating facilities, or to show loyalty to a particular merchant, or to a service provider such as a financial institution (e.g., Chase Manhattan Bank). In addition to receiving discounts or financial awards, an incentive to the consumer may include redeemable goods or services, or special recognition of some sort, such as an upgrade to goods or services purchased by the consumer. Often, financial institutions, such as an issuing bank or acquiring bank, provide financial and logistic support to the loyalty program. Loyalty programs may be associated with various transaction payment process programs such as a credit card program, a charge card program, a debit card program, a prepaid card program, or a gift card program.
One indicator of success for any loyalty program is how well it can target consumers that will be positively influenced to participate in the program in exchange for receiving the incentives described by and provided through the loyalty program.
These loyalty programs are typically constructed, marketed, qualified, fulfilled, or refined with limited interaction or collaboration between the various participants of the programs, where the participants may include merchants, financial institutions such as acquirers and issuers, transaction handlers such as credit card companies (i.e., Visa, MasterCard, American Express, etc.), and consumers such as an account holder. For example, a merchant may wish to participate in a co-branded credit card loyalty program (i.e., a Southwest Airlines Chase Manhattan Bank Visa Credit Card). The merchant finds, however, that it will be confined to loyalty program features set solely by the issuing bank (i.e., Chase Manhattan Bank), the features include an overly restrictive credit limit, a conservative bonus mile to purchase ratio, or a limited redemption points option. As such, the merchant will be precluded from finely targeting the merchant's most desired consumers would not be positively influenced to participate in the program in exchange for receiving such limited incentives. The level of loyalty program feature confinement is especially prominent among merchants with a smaller portion of the market who lack influence over the loyalty program and its participants.
A further draw back is that loyalty programs may have limited access to detailed transaction data. For example, some loyalty program participants, such as financial institutions, may rely on their own transaction data records and history to determine the type of incentive to provide to a consumer for conducing one or more transactions. This data history, however, may be limited in scope depending on the degree of transaction specificity that the issuer collects or is able to maintain. Similarly, merchants wishing to set up a loyalty program may solicit financial institutions for transaction data history information, without success in gaining access to the full scope of the transaction data. Even if a merchant gains access to the transaction data, the transaction data may not be in a form the merchant can effectively utilize.
The lack of uniformity in handing transaction data may hamper accurate communication between participants in a loyalty program. For example, acquirers may identify a single merchant differently; one acquirer may identify a merchant by its name and address while another acquirer may identify the same merchant by its name and franchise store number. Similarly, each participant in the loyalty program may be accustomed to processing transaction data in a particular format that may not be the same as the format of another participant of the loyalty program. For example, a merchant that is an airline company may analyze transaction data in units of “frequent flyer program bonus miles per dollar” while an issuer may record dollars spent per month.
Thus, there is a need for a loyalty program having access to detailed transaction data while maintaining a uniform communication protocol between the participants of the program. Further, there is a need for a loyalty program capable of accommodating customizations from its various participants.
SUMMARY
In one implementation, for each transaction processed by a transaction handler, a comparison is made of at least one of an account, an issuer of the account, a merchant, and at least one of the items in the transaction to loyalty data in a loyalty database to find at least one predetermined match. Each predetermined match has an associated loyalty reward that is a function of the transaction and is denominated in a loyalty currency. For each predetermined match, the loyalty currency of the associated loyalty reward is added to a balance of the same loyalty currency in a loyalty account associated with the account of the account holder. The loyalty account associated with the account of the account holder can have a balance for each of a plurality of different loyalty currencies. The associated loyalty reward can be calculated as a function of the transaction at least in part from the number of a financial currency for the payment for the transaction, the number of the items in the transaction, the number of the items in the transaction, and/or the number of a particular said item in the transaction.
In another implementation, a loyalty program is operated within a payment processing system by establishing a communication protocol for the transfer of data via a customer-facing channel. When the payment processing system processes a transaction engaged in between a merchant and an account holder, in addition to obtaining payment for the merchant from the account associated with the consumer transaction device involved, a loyalty currency is stored in a loyalty account associated with the account holder if the account holder is enrolled in a loyalty program and if criteria for applying the loyalty program are satisfied. The account holder is provided access to the loyalty account via the customer-facing channel.
In yet another implementation, a loyalty program is operated within a payment processing system by establishing a communication protocol for the transfer of data via a customer-facing channel and by storing criteria associated with each loyalty program operated within the payment processing system in a loyalty program database. Further, a loyalty account is configured in an account holder database for each account holder enrolled in a loyalty program operated within the payment processing system. When the payment processing system processes a transaction engaged in between a merchant and an account holder, in addition to obtaining payment for the merchant from the account associated with the consumer transaction device involved, a loyalty currency is stored in the loyalty account associated with the account holder engaged in the transaction. This currency is stored if the account holder is associated with one of the loyalty accounts that is configured in the account holder database and if the plurality of criteria associated with one of the loyalty programs in which the account holder is enrolled is satisfied. The account holder is provided access the loyalty account via the customer-facing channel.
In still another implementation, a payment processing system is provided in which a merchant engages in a transaction with an account holder upon an account associated with a portable consumer device issued by an issuer. A transaction handler further coordinates the transfer of monetary currency to an acquirer of the merchant and the transfer of loyalty currency to a loyalty account of the account holder in response to the transaction satisfying the application criteria of a loyalty program and in response to the account holder being enrolled in that loyalty program. The account holder accesses the loyalty account using a customer-facing channel that is in communication with the transaction handler and is provided by a sponsor of the loyalty program.
BRIEF DESCRIPTION OF THE DRAWINGS
Implementations of the invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like elements bear like reference numerals.
FIG. 1 is a block level diagram illustrating an exemplary payment processing system;
FIG. 2 is a block level diagram illustrating an exemplary multi-vendor loyalty program operated within the system illustrated in FIG. 1 ;
FIG. 3 is a schematic flowchart illustrating an exemplary implementation of a loyalty program according to the implementation depicted in FIG. 2 .
DETAILED DESCRIPTION
Implementations propose a structure for developing and executing a loyalty program. As background information for the foregoing and following description, as will be readily understood by persons of ordinary skill in payment processing systems, a transaction such as a payment transaction in a payment processing system can include participation from different entities that are each a component of the payment processing system. An exemplary payment processing system is depicted in FIG. 1 as the payment processing system 100 . The payment processing system 100 includes the issuer 104 , the transaction handler 106 , such as a credit card company, the acquirer 108 , the merchant 110 , or the consumer 102 . The acquirer 108 and the issuer 104 can communicate through the transaction handler 106 . Merchant 110 may utilize at least one Point of Service “POS” terminal that can communicate with the acquirer 108 , the transaction handler 106 , or the issuer 104 . Thus, the POS terminal is in operative communication with the payment processing system 100 .
Typically, a transaction begins with the consumer 102 presenting a portable consumer device 112 to the merchant 110 to initiate an exchange for a good or service. The portable consumer device 112 may include a payment card, a gift card, a smartcard, a smart media, a payroll card, a health care card, a wrist band, a tag, a badge, a machine readable medium containing account information, a keychain device such as the SPEEDPASS® commercially available from Exxon-Mobil Corporation, a supermarket discount card, a cellular telephone, a personal digital assistant, a pager, a security card, an access card, a wireless terminal, or a transponder. The portable consumer device 112 may include volatile and/or non-volatile memory to store information such as the account number or an account holder's name.
The merchant 110 may use the POS terminal to obtain account information, such as an account number, from the portable consumer device 112 . The portable consumer device 112 may interface with the POS terminal using a mechanism including any suitable electrical, magnetic, or optical interfacing system such as a contactless system that uses a radio frequency or a magnetic field recognition system, or a contact system that uses a magnetic stripe reader. The POS terminal sends a transaction authorization request to the issuer 104 of the portable consumer device 112 . Alternatively, or in combination, the portable consumer device 112 may communicate with the issuer 104 , the transaction handler 106 , or the acquirer 108 .
The issuer 104 may authorize the transaction using the transaction handler 106 . The transaction handler 106 may also clear the transaction. Authorization includes the issuer 104 , or the transaction handler 106 on behalf of the issuer 104 , authorizing the transaction in connection with the issuer 104 's instructions such as through the use of business rules. The business rules could include instructions or guidelines from the transaction handler 106 , the consumer 102 , the merchant 110 , the acquirer 108 , the issuer 104 , a financial institution, or combinations thereof. The transaction handler 106 may maintain a log or history of authorized transactions. Once approved, merchant 110 will record the authorization, allowing the consumer 102 to receive the good or service.
Merchant 110 may, at discrete periods, such as the end of the day, submit a list of authorized transactions to the acquirer 108 or other components of the payment processing system 100 . The transaction handler 106 may compare the submitted authorized transaction list with its own log of authorized transactions. If a match is found, the transaction handler 106 may route authorization transaction amount requests from the corresponding acquirer 108 to the corresponding issuer 104 involved in each transaction. Once the acquirer 108 receives the payment of the authorized transaction amount from the issuer 104 , it can forward the payment to merchant 110 less any transaction costs, such as fees. If the transaction involves a debit or pre-paid card, the acquirer 108 may choose not to wait for the initial payment prior to paying the merchant 110 .
There may be intermittent steps in the foregoing process, some of which may occur simultaneously. For example, the acquirer 108 can initiate the clearing and settling process, which can result in payment to the acquirer 108 for the amount of the transaction. The acquirer 108 may request from the transaction handler 106 that the transaction be cleared and settled. Clearing includes the exchange of financial information between the issuer 104 and the acquirer 108 and settlement includes the exchange of funds. The transaction handler 106 can provide services in connection with settlement of the transaction. The settlement of a transaction includes depositing an amount of the transaction settlement from a settlement house, such as a settlement bank, which the transaction handler 106 typically chooses, into a clearinghouse, such as a clearing bank, that the acquirer 108 typically chooses. The issuer 104 deposits the same from a clearinghouse, such as a clearing bank, which the issuer 104 typically chooses into the settlement house. Thus, a typical transaction involves various entities to request, authorize, and fulfill processing the transaction.
Payment processing system 100 may also process loyalty programs. For example, when the consumer 102 makes a purchase using the portable consumer device 112 at a store of the merchant 110 , the consumer 102 may be eligible to receive an incentive, such as a frequent flyer point, that can be applied toward a reward, such as a free airline ticket. In one implementation, when consumer 102 makes such a purchase, the consumer's 102 eligibility is determined by an implementer. By way of example, and not by way of limitation, an implementer may be the transaction handler 106 . In such an implementation, the transaction handler 106 , upon receiving the transaction data, may compare the data to a database of loyalty programs to determine if the transaction meets the eligibility requirements of any loyalty program, the rules and parameters of each loyalty program having been established by its sponsor. In some implementations, the sponsor may be the issuer. In yet other implementations, the sponsor may be, for example, a transaction handler, such as a credit card company, an acquirer, a merchant, a third-party, or a combination thereof.
If the transaction meets the eligibility requirements of a given loyalty program, the transaction handler may then calculate a loyalty currency to be applied to a reward account of the consumer using rules and parameters of the program. The loyalty currency may, in some implementations, be frequent flyer points that can be applied toward a free airline ticket. In other implementations, the loyalty currency may be cash back, future discounts, coupons, donations to selected charities, special rates, or any other form of loyalty program reward, or combination thereof.
For example, the consumer 102 may be a participant of a Saks Fifth Avenue® loyalty program having a purchase-to-point ratio of $100 (U.S.)/1 point. Upon receiving a request to process a transaction for $1000 (U.S.) between the consumer 102 and a merchant 110 , in this case being a Saks Fifth Avenue® store, the transaction handler 106 would compare the transaction data to the eligibility requirements of all known loyalty programs. Once it is determined the transaction meets the eligibility requirements of a loyalty program, here that of the Saks Fifth Avenue® loyalty program, the transaction handler 106 calculates the loyalty currency based on the rules and parameters of the loyalty program, in this illustration equaling 10 points. Once the points are determined, the value of the currency (here being measured by ‘points’) can be tracked and accumulated in an reward account at a point bank, that may, for example, also be a function performed by the transaction handler 106 .
In one implementation, the point bank may have standardized input and output format structures that are communicated to sponsors of loyalty programs such that communication with the point bank is facilitated and controlled. The standardized input and output format structures allow for a plurality of vendors that may be third-parties to interact in a compatible fashion with the point bank and provide services to the sponsors and consumers of the loyalty program. Thus, for example, although the same entity is acting as the point bank for each loyalty program, the appearance and functionality of each loyalty program can be tailored to the sponsor's or consumer's needs. Sponsors that have multiple or complex loyalty programs can collaborate with third-party vendors to assist in each program's development and execution. Vendors may, for example, provide services such as hosting websites, managing rewards catalogs, facilitating fulfillment of loyalty program incentives, and providing customer support.
Where a third-party vendor 114 is used to establish customer-facing channels, consumer 102 may use the third-party vendor 114 's services when redeeming, verifying, updating information, or otherwise accessing their reward account. Through the use of standardized input and output format structures, communication with the implementer (i.e., the transaction handler 106 ) is transparent to the consumer 102 , and the consumer 102 will perceive an experience of interacting solely with the loyalty program sponsor. Thus, through collaboration with the third-party vendor 114 , the loyalty program sponsor can, for example, create a custom interface through a website that they have already established and branded themselves rather then having the consumer 102 utilize an unfamiliar interface provided by the point bank.
In another implementation, problems can be addressed or solved by an implementer who is providing a loyalty program and also keeping track of loyalty program currency in a loyalty program currency bank (i.e., a point bank), where the implementer is also processing transactions that are eligible for point credit in the loyalty program. In this implementation, an efficiency is gained by allowing this implementer to calculate the loyalty points for account holders (e.g., cardholders) as opposed to transmitting that information to a third-party for processing and points calculation. Rather, this implementer can perform this function on behalf of all of the issuers in the payment system that are participating in the loyalty program. Moreover, this implementation allows for multiple vendors to share a common set of standards. This sharing makes these vendors interoperable in the loyalty program so as to allow participating member banks (e.g., issuers) to contract with these vendors for the provision of programs (e.g., customer-facing program functions), such as providing websites, providing reward catalogs, customer service, and marketing activities. By implementing such a multiple and interoperable vendor model for a loyalty program, the implementer is able to provide a baseline loyalty program processing service in a cost effective manner, while allowing the member banks (e.g., issuers) and other participants in the loyalty program sufficient flexibility to create different consumer (i.e., account holder or cardholder) experiences. As such, the implementer may also be operating the “core” component of the payment processing system (i.e., such as the exemplary system shown in FIG. 1 ), while member banks (e.g., issuers) contract with the multiple and interoperable vendors to help the banks to differentiate themselves on customer service and reward options.
Referring to FIG. 2 , a block diagram illustrates an exemplary implementation of a loyalty program structure 200 that is compatible with a plurality consumer interfaces provided by different vendors and/or agents thereof. A bulk file management system 202 may be used to facilitate communication of information in data files from external entities with an operational data store 204 within a point bank. The operational data store 204 may be a database such as a relational database and may store all information pertaining to each consumer's reward account. The data files may include: (i) real time settlement files (“RSI”) obtained after the purchase of a good or service from the merchant has been cleared and settled; (ii) participation agreement files (“PA”) from the issuer that delineate how the issuer has agreed to participate in the loyalty program; (iii) earn engine files that may include loyalty program business rules; and (iii) other loyalty program files that delineate the parameters of the loyalty program such as: (a) files containing consumer profiles including an account number within the payment processing system; (b) a category of the of the account such as a “gold account; (c) the number of people on the account; and the like. The data files may further include information for the point bank such as transaction loads, bonus loads, bonus adjustments, aggregation files related to the account associated with the payment processing system, and fulfillment transaction histories (e.g., the history of transactions involving the account associated with the payment processing system).
Once an activity triggers an incentive, such as a purchase at the store of the merchant, information from the operational data store 204 may pass to the loyalty program incentive calculator 206 . The loyalty program incentive calculator 206 may be an engine that utilizes software to run calculations given loyalty program business rules, such as loyalty reward and currency algorithms, to determine whether the transaction qualifies for an incentive of the loyalty program, and to compute the amount and form of any of several different loyalty currencies that have been earned. This information can be communicated to the operational data store 204 . There, the particular type of loyalty currency that has been earned by the consumer is added to a balance of that loyal currency maintained at reference numeral 220 ( d ) within the consumer's reward account 218 ( c ) of operational data store 204 . Within operational data store 204 , which is preferably maintained by the transaction handler or agent thereof, there are reward accounts 218 ( 1 ) through 218 (C), and wherein within each reward account 218 ( c ) there are currency balances 220 ( 1 ) through 220 (D).
In some implementations, the loyalty program incentive calculator 206 may further include issuer and merchant transaction histories such as transaction histories involving points, bonuses, and incentives. The loyalty program incentive calculator 206 may also access issuer or consumer profiles to implement the loyalty program business rules for the loyalty program in which both the issuer and the consumer are participants.
Regular maintenance activities on the reward accounts and the coordination of outgoing reports and summaries may be conducted through a batch activities system 208 in communication with the operational data store 204 . By way of example, and not by way of limitation, such activities may include sweeping the reward account daily, monitoring the inactivity of a reward account, monitoring of point expiration or validity, creating reports, file management activities such as file extracts and file updates, calculation of fees, and generation of bills. Consequently, daily, weekly, and monthly events such as reward account monitoring and maintenance can be done in communication with the operational data store 204 .
Interface layer 210 provides a means for a participant 216 ( b ) to interact with the operational data store 204 , where the participants 216 in FIG. 2 include participant 216 ( 1 ) through participant 216 (B). In one implementation, participants 216 may be sponsors of the loyalty programs using an interface 214 ( a ) established by the point bank, the interfaces 214 in FIG. 2 include interface 214 ( 1 ) through interface 214 (A). In another implementation, the participants 216 may be consumers, where each interface 214 ( a ) is a customer-facing program provided by a sponsor or its agent of a different loyalty program or by a third-party vendor or agent thereof. Each interface 214 ( a ) communicates with the operational data store 204 using a standard input and output protocol defined by the point bank.
Where a participant is a sponsor of a loyalty program, interface 214 ( a ) may be used to create and manage an issuer sponsor. For example, the sponsor may set up preferences for its loyalty program business rules, such as delineating a loyalty currency that it can offer to a consumer who is utilizing a portable consumer device in one or more transactions, and where the device is associated with that sponsor.
The consumer who participates in the sponsor's loyalty program may manage a reward account stored at the point bank via an interface 214 ( a ), the interface 214 ( a ) being a customer-facing program. Where the interface 214 ( a ) has been provided by the sponsor or by third-party vendor at the direction of the sponsor, the sponsor can choose to allow the consumer to, for example, check the consumer's reward account balance, opt-in or opt-out of certain features of a loyalty program, or redeem incentives. Alternatively or in combination, the interface 214 ( a ) may offer consumer support and access to administrative services. Additionally, the interface layer 210 may include a security service layer such that data may be encrypted as it is passed from the operational data store 204 to the interface 214 accessed by the participant 216 .
In collaboration with the sponsors, third-party vendors may further provide services including hosting the consumer (account holder) web site, cataloging the services that the issuer or the acquirer can provide to the consumer or the merchant respectively, fulfillment of loyalty program incentives, providing voice response unit (“VRU”) and consumer services.
One entity may provide several components of the loyalty program structure 200 while other entities, such as third-parties, may provide other components. In one implementation, a transaction handler may: (i) access the transaction handler's data files stored in the bulk file management system 202 ; (ii) communicate with the operational data store 204 ; (iii) determine the eligibility of a purchase toward an incentive; (iv) determine the value of the incentive via the loyalty program incentive calculator 206 ; (v) conduct activities using the batch activities system 208 on the reward account stored in the operational data store 204 ; and (vi) communicate with aspects of the interface layer 210 while interacting with a plurality of vendors that provide the interfaces 214 ( 1 )- 214 (A).
As previously mentioned, compatibility between the plurality of vendors providing interfaces 214 and the transaction handler providing the other components in the loyalty program structure 200 may be achieved via standardized communication formats. For example, one interface 214 ( a ) may be an interactive account holder website that accepts consumer input such as account holder name. The account holder name may be in the format of first name, middle initial, and last name. Alternatively, or in combination, the account holder may enter an account number that is associated with the payment processing system. The account number may be in the format such that the last four digits must be entered along with an expiration date for the portable consumer device associated with the account. In another example, the sponsor may create a profile using an interface 214 ( a ) such that a Globally Unique IDentifier (GUID) is utilized to identify the issuer. Here, the GUID will be unique within the payment processing system. The GUID for the sponsor may be in a standard format that the transaction handler utilizes to process the transactions of the issuer within the loyalty program structure 200 .
To illustrate, a first issuer, may customize the services that the first issuer can provide to the consumer despite the fact that the first issuer is utilizing the same transaction handler to process transactions through the payment processing system as a second issuer. The first issuer may contract with third-party vendors to provide a unique website describing the loyalty program in which the first issuer is a participant. For example, the first issuer may have its own logo on the website describing the loyalty program that the first issuer is a participant and/or the first issuer may advertise a point-to-purchase ratio that the issuer can provide to the consumer which may be different from a point-to-purchase ratio that the second issuer may be able to provide to the consumer. In this manner, the first issuer may distinguish itself from the second issuer within the payment processing system.
Referring to FIG. 3 , a schematic flowchart illustrates an exemplary implementation of a loyalty program according to the implementation depicted in FIG. 2 . In this illustration the point bank is discussed in terms of the transaction handler. However, those of ordinary skill in the art will realize that the point bank may be another entity either internal to or external of a payment processing system without changing the fundamentals of the discussion.
Initially, a transaction handler establishes a database or other record of the rules and parameters of each loyalty program sponsored by a sponsor ( 302 ). In one implementation, to establish a loyalty program, the sponsor may utilize an interface provided by the transaction handler that is capable of communicating with an operational data store. In another implementation, a sponsor may use another means to communicate with the transaction handler, such as through a representative.
In conjunction with establishing a loyalty database, the transaction handler also establishes a database of consumer reward accounts wherein a plurality of different loyalty currencies will be banked for each consumer enrolled in a loyalty program maintained in the loyalty database ( 304 ). When the transaction handler receives a consumer file of a consumer that has enrolled in a loyalty program, the transaction handler opens a loyalty account for the consumer ( 306 ).
Upon the receipt of a request to process a transaction that was engaged in by a merchant and a consumer upon a consumer account issued by an issuer ( 308 ), the transaction handler compares the transaction data with the eligibility requirements of the loyalty programs stored in the loyalty database ( 310 ). If the transaction meets the eligibility requirements of a loyalty program, the transaction handler utilizes the rules and parameters of the program to calculate and award one or more different types of loyalty currencies to the consumer's reward account ( 312 ). Finally, the transaction handler processes the transaction as described in connection with FIG. 1 ( 314 ).
Once a loyalty program or a reward account has been established, the transaction handler may further receive a request to access information from the operation data store via an interface using a standard input-output protocol established by the transaction handler ( 316 ). Where the request is received from an issuer, or other sponsor of a loyalty program, the request is for information pertaining to the issuer's loyalty program. The issuer may further use the user interface to modify the rules and parameters of a loyalty program. Alternatively, where a request is received from a consumer, information pertaining to the consumer's reward account is accessed. Using the interface, the consumer may then, for example, choose to opt in or out of features, redeem loyalty currency, or update personal information.
The interface used may be provided and hosted by the transaction handler. In other implementations, the interface is provided by the loyalty program's sponsor. In yet other implementations, the sponsor uses a third-party vendor to provide the interface. In each case, the interface communicates with the operational data store using standard communication protocol, thereby making the communication with the transaction handler transparent to the participant.
The loyalty program structure described can be utilized within an exemplary automated loyalty program platform associated with the payment processing system. The loyalty program participants can utilize portions of the vendor services, such as web site interfaces that may be linked to the automated loyalty program platform, to develop or implement the parameters of the loyalty program.
In one implementation the automated loyalty program platform is a platform that the merchant or the issuer may access to set up loyalty program rules and/or parameters that the merchant wants to market to consumers. Once the loyalty program rules and/or parameters are set up, the automated loyalty program platform automatically generates promotions based on the rules and/or parameters and automatically implements the loyalty program rules and/or parameters as payment transactions are conducted through the payment processing system.
The automated loyalty program platform may be accessible to the merchant through the use of a device having a hardware component such as a CPU and/or a terminal and a software component such as code, microcode, applets, or modules that assist the merchant in conducting its business. The device, such as a POS terminal or a computer, may access the automated loyalty program platform through a network. The network may be the Internet.
The merchant may use the device to access the automated loyalty program platform to set up at least one parameter and/or loyalty program rule for a loyalty program promotion that the merchant wishes to market to past or potential consumers. For example, the merchant may set up a profile linked to a unique identifier for the merchant. The profile may include loyalty program rules that govern the creation and implementation of promotions that the merchant wants to market to consumers. The loyalty program rules may take on the form of “if parameter one occurs then offer parameter two.” For example, the promotion may be a coupon promotion, such as a coupon indicating that if a purchase at the merchant's store made with an account associated to a payment processing system exceeds $100 in value, then 10% will be taken off the purchase value; the promotion may be a spend-and-get promotion such as if the consumer conducts four purchases made with the account at the merchant's store, the consumer's fifth purchase at the merchant's store will result in $10.00 being credited to the account associated with the payment processing system. The loyalty program rules and/or parameters may be predetermined such that the merchant picks them a la cart within a menu provided by the automated loyalty program platform, or they may be customized.
The automated loyalty program platform may also be in communication with the transaction handler and/or the issuer. Therefore, the automated loyalty program platform may access a transaction history database maintained by the transaction handler. Alternatively, the automated loyalty program platform may be part of the transaction handler. The automated loyalty program platform may communicate the merchant's loyalty program rules and/or parameters along with portions of the transaction information it received from the merchant's POS device in order to receive validation that the issuer supports the application of the transaction toward the loyalty program. For example, the consumer may have a promotion for $20 credit to be applied to the consumer's account within the payment processing system when making a $100 purchase at the merchant's store. When the automated loyalty program platform receives a transaction message indicating that the consumer has made a purchase of $100 at the merchant's store, it may send this information to the consumer's issuer to verify that the issuer agrees that the $100 purchase qualifies for the $20 promotion and for the issuer to indicate that the $20.00 credit will be applied and reflected in the consumer's statement of account.
For example, the merchant may be an office equipment store. The merchant may have overstocked paper within the month of March; consequently, the office equipment store may wish to provide a promotion to consumers living within 5 miles from its store. The office equipment store may use its POS device to access the automated loyalty program platform to set up a loyalty program rule offering a free pack of paper with the purchase of a printer toner. The automated loyalty program platform may then automatically create a coupon indicating that a free pack of paper is offered with the purchase of a printer toner. The coupon may have the office equipment store's logo or other customized promotional information. The automated loyalty program platform may then access a database containing the billing address of consumers that are account holders within the payment processing system. If the billing address of the consumer is within five miles of the location of the office equipment store, then the automated loyalty program platform addresses the generated coupon to the consumer with the billing address within five miles of the location of the office equipment store. Similarly, the office equipment merchant may wish to send out a promotion of 15% off to all account holders within the payment processing system that have purchased paper within a predetermined past time period. The automated loyalty program platform may access and gather select data (i.e., e-mail addresses) from a database containing past transaction history of account holders within the payment processing system. In gathering the select data, the platform may filter out those consumers that have purchased paper from any office equipment store within the predetermined past time period. The automated loyalty program platform may then automatically address the 15% off promotion to each e-mail address of each consumer that purchased paper from any office equipment store, such as from the competitors of the office equipment store that created the promotion. The consumer may then apply the coupon in an Internet purchase made via the office equipment store's webpage.
Various terms may be used herein, which are to be understood according to the following descriptions 1 through 8:
1. Acceptance point device includes a device capable of communicating with a payment device, where the acceptance point device can include a Point of Device (POS) device, a smartcard, a payment card such as a credit or debit card with a magnetic strip and without a microprocessor, a keychain device such as the SPEEDPASS™ commercially available from Exxon-Mobil Corporation, a cellular phone, personal digital assistant (PDA), a pager, a security card, an access card, a smart media, a transponder, personal computer (PC), tablet PC, handheld specialized reader, set-top box, electronic cash register (ECR), automated teller machine (ATM), virtual cash register (VCR), kiosk, security system, or access system;
2. Account holder or consumer includes any person or entity with an account and/or a payment device associated with an account, where the account is within a payment system;
3. Issuer includes any entity that issues one or more accounts and/or payment devices;
4. Merchant includes any entity that supports an acceptance point device;
5. Participant includes any consumer, person, entity, charitable organization, machine, hardware, software, merchant or business who accesses and uses the system of the invention, such as any consumer (such as primary member and supplementary member of an aggregate consumer account), retailer, manufacturer, and third-party provider, and any subset, group or combination thereof;
6. Redemption includes obtaining a reward using any portion of points, coupons, cash, foreign currency, gift, negotiable instruments, or securities;
7. Reward includes any discount, credit, good, service, package, event, experience (such as wine tasting, dining, travel), or any other item; and
8. Payment device includes a card, smartcard, ordinary credit or debit cards (with a magnetic strip and without a microprocessor), a keychain device (such as the SPEEDPASS™ device commercially available from Exxon-Mobil Corporation), cellular phone, personal digital assistant (PDA), pager, payment card, security card, access card, smart media, or transponder, where each payment device can include a loyalty module with a computer chip with dedicated hardware, software, embedded software, or any combination thereof that is used to perform actions associated with a loyalty program.
It should be understood that the present invention can be implemented in the form of control logic, in a modular or integrated manner, using software, hardware or a combination of both. The steps of a method, process, or algorithm described in connection with the implementations disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The various steps or acts in a method or process may be performed in the order shown, or may be performed in another order. Additionally, one or more process or method steps may be omitted or one or more process or method steps may be added to the methods and processes. An additional step, block, or action may be added in the beginning, end, or intervening existing elements of the methods and processes. Based on the disclosure and teachings provided herein, a person of ordinary skill in the art will appreciate other ways and/or methods to implement the present invention.
The specification and figures are to be regarded in an illustrative manner, rather than a restrictive one, and all such modifications are intended to be included within the scope of present invention. The steps recited in any of the method or process claims may be executed in any order and are not limited to the order presented in the claims. The invention has been described with reference to specific examples and implementations for illustrative purposes only and it is understood that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. | Loyalty programs can be operated within a payment processing system having multiple vendors, thereby providing access to detailed transaction data and with the flexibility for customization of the loyalty programs themselves, by establishing a communication for the transfer of data via a customer-facing channel. When the payment processing system processes a transaction between a merchant and an account holder, in addition to obtaining payment for the merchant from the account via an acquirer and an issuer, respectively, a transaction handler tabulates and stores different types of loyalty currencies in a loyalty reward account associated with the account holder if the account holder is enrolled in a loyalty program and criteria for applying the loyalty program are satisfied. The account holder is provided access to the loyalty account via the customer-facing channel. | 6 |
[0001] This application is a Continuation-in-Part of U.S. patent application Ser. No. 11/797,941, filed on May 9, 2007, and is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a dryer using heated air to dry items. More particularly, the present invention relates to a dryer a structure to enhance moisture removal from the items in the dryer. The present invention improves drying efficiency using the structure.
DISCUSSION OF THE RELATED ART
[0003] Clothes dryers basically work in the following manner. The dryer sucks in air from the surrounding area. The dryer heats the air using an electric heating element, a gas burner and the like. The air passes into a tumbler housed within the dryer once it is heated. The hot air evaporates water from the clothes as they spin inside the tumbler. The dryer then forces the water evaporated from the clothes along with the hot air outside its assembly. Typically, a vent allows the air and moisture to exit the room.
[0004] Articles, such as clothes, towels, rugs and the like, take a certain amount of time to dry. The amount of time varies according to the article being dried. Other factors to this time period are energy capacity of the heating element, efficiency of heat transfer, air flow capacity, vapor pressure and the like. Some of these factors may be beyond the control of the dryer, while others may be controlled or monitored to improved drying times and efficiency.
[0005] Dryers use the vapor pressure of the air in the home, laundry room, basement and the like, which can be less than desirable for drying articles. The grains of moisture in a home may range from about 45 to about 110 grains of water vapor per pound of air. Grains of water vapor per pound of air (grains/lb) indicate the density measurement of water vapor in air. For example, 14 cubic feet of air is about 1 pound (lb) of air. Approximately 7000 grains of water vapor are in about one lb of air. By measuring the volume of air, an average number of grains of water vapor for the volume may be determined.
[0006] The air sucked into the dryer is heated during the time period for drying the articles. The higher the grains/lb of water in the air, the longer the drying period. For example, air having about 110 grains/lb. may take twice as long as air having about 45 grains/lb. Thus, conditions for drying may be less than optimal when using damp air surrounding the dryer.
SUMMARY OF THE INVENTION
[0007] The disclosed embodiments of the present invention relate to a dryer apparatus that improves drying efficiency and reduces the amount of time needed to dry articles. The dryer removes moisture from the air prior to entering the drum, tumbler or housing with the dryer that holds the articles. The disclosed embodiments of the present invention seek to improve the condition of the air moisture prior to drying.
[0008] If the grains per pound of water vapor of the air to be heated are low, then the articles within the dryer are dried faster. The relationship is established because the vapor pressure is reduced, which results in a quicker drying period. Thus, the time and energy to dry an article is reduced. Preferably, a grain count of about 10 to 40 grains/lb reduces the drying period to about a third of the normal drying period.
[0009] Vapor pressure dictates how much energy is needed to evaporate the water from the drying article. A certain amount of energy, such as about 1060 British Thermal Units (Btus), is needed to evaporate 1 pound of air. Reducing the vapor pressure in that air would reduce the amount of energy needed to evaporate the pound of air. Vapor pressure may vary according to location and other conditions, but it can almost always be reduced to a lower value. The disclosed embodiments of the present invention relates to reducing the vapor pressure in air so as to generate better air for drying clothes and lower costs. Thus, the disclosed embodiments of the present invention reduces the grains/lb of the air flowing into the dryer from the outside to improve drying times and efficiency.
[0010] The disclosed embodiments of the present invention achieve improved drying efficiency by using an intake to suck in air separate from the inlet air path of the dryer. In other words, air enters the dryer from two different locations. One air stream goes through the dryer as normal, while the other flows through a heating element. Both streams flow through a wheel that removes water from the water, except the heated air serves to regenerate the desiccant material within the wheel. Thus, the desiccant material held by the wheel is dried before being placed back into the path of the inlet air going into the drum of the dryer.
[0011] Orientation of the airstreams according to the disclosed embodiments helps in the elimination of lint from the dryer. Lint may reduce drying efficiency within the dryer by reducing the removal of moisture from the air entering the dryer. Further, the disclosed embodiments disclose a structure that places a heating element where it can do the most good in the dryer. The disclosed configuration also reduces the vapor pressure of the air used for regeneration within the dryer.
[0012] According to the disclosed embodiments, a dryer is disclosed. The dryer includes an inlet air path. The dryer also includes a heating element to heat an intake air stream separate from the inlet air path. The dryer also includes a wheel positioned to receive air from the inlet air path and heated air in the intake air stream. The wheel includes desiccant material. The dryer also includes an outlet air path to combine the heated air in the intake air stream with an outlet air stream.
[0013] Further according to the disclosed embodiments, another dryer is disclosed. The dryer includes a desiccant wheel regeneration system that dries a desiccant material within the desiccant wheel including an air intake to allow an intake air stream to flow through a heating element to generate heated air that dries the desiccant material and then combines with air expelled from the dryer.
[0014] Further according to the disclosed embodiments, a method for drying an article is disclosed. The method includes creating an intake air stream separate from an inlet air path. The method also includes heating air within the intake air stream. The method also includes flowing the heated air through a wheel including desiccant material. The method also includes removing at least one water molecule from air within the inlet air path with the desiccant material.
[0015] Further according to the disclosed embodiments, a dryer is disclosed. The dryer includes an intake located on a side of the dryer to allow intake air to enter the dryer and heated with a heating element. The dryer also includes a fan positioned with the intake to draw the intake air into the dryer.
[0016] Further according to the disclosed embodiments, a method for regenerating a desiccant wheel in a dryer also is disclosed. The method includes creating an intake air stream through an intake. The method also includes heating the intake air stream. The method also includes flowing the intake air stream through a portion of desiccant material. The method also includes combining the intake air stream with an outlet air path.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The accompanying drawings are included to provide further understanding of the invention and constitute a part of the specification. The drawings listed below illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention, as disclosed by the claims and their equivalents.
[0018] FIG. 1 illustrates a dryer having a desiccant wheel according to the disclosed embodiments.
[0019] FIG. 2 illustrates another dryer having a desiccant wheel according to the disclosed embodiments.
[0020] FIG. 3 illustrates a flowchart for drying an article according to the disclosed embodiments.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] Aspects of the invention are disclosed in the accompanying description. Alternate embodiments of the present invention and their equivalents are devised without parting from the spirit or scope of the present invention. It should be noted that like elements disclosed below are indicated by like reference numbers in the drawings.
[0022] FIG. 1 depicts a dryer 100 having a desiccant wheel 140 according to the disclosed embodiments. Dryer 100 is a dryer using forced, heated air to remove moisture and wetness from articles, such as clothes, towels, fabric, dishes, household items, and the like. Article 102 represents one of such articles, or a plurality of articles, within dryer 100 . Preferably, article 102 is contained, or held, within a rotating drum 104 . Article 102 tumbles within drum 104 to allow the heated air to flow over its surface to remove moisture.
[0023] Dryer 100 intakes outside air from its surrounding environment and expels the air after it has cycled through drum 104 . This process is disclosed in greater detail below. Dryer 100 also includes controls 106 to adjust settings and operations for drying articles. Controls 106 may be knobs, buttons, displays, and the like. Indicator 108 alerts a user that lint screen 110 should be cleaned. Preferably, indicator 108 is a light that comes on to alert the user.
[0024] Dryer 100 also includes door 112 . FIG. 1 shows door 112 on the front side of dryer 100 , but door 100 may be placed on any side or surface of dryer 100 . For example, door 112 may be located on the top of dryer 100 if that side is considered more convenient or accessible. Drum 104 holds articles 102 . Article 102 is placed into and removed from drum 104 via door 112 . Thermostat 114 controls the temperature in drum 104 and uses information provided by sensor 116 to determine whether to increase or decrease the amount of heated air forced onto article 102 .
[0025] Belts 118 rotate drum 104 . Although FIG. 1 shows two belts, the number of belts may vary according to the needs and size of dryer 100 . Moreover, other means for rotating drum 104 can be employed and dryer 100 is not limited to using belts. Belts 118 may be attached to a rotor 120 . Rotor 120 is controlled by motor 122 , which receives commands set by controls 106 . Again, rotor 120 and motor 122 may be any configuration or type commonly used in dryers.
[0026] Power to dryer 100 is provided via power cord 124 . Preferably, power cord 124 includes a 220 volt plug that interacts with a wall outlet. Alternatively, power may be supplied through two 110 volt plugs 126 stored within dryer 100 . Plugs 126 provide an alternate power source should the 220 volt plug be unavailable.
[0027] Dryer duct 130 couples vent 134 of dryer 100 to the outside. Preferably, duct 130 connects to a vent within a wall. Duct 130 is coupled to dryer 100 using clips 132 . Duct 130 may be comprised of rigid material that does not collapse during common use. The rigidity ensures that good air flow occurs at all times while dryer 100 is in use.
[0028] Lint screen 110 separates drum 104 from vent 134 . Vent 134 allows air from drum 104 to exit dryer 100 through duct 130 . Fan 154 draws air filled with moisture from article 102 into vent 134 . If the air is saturated with moisture, then the removal of moisture from article 102 is compromised. Fan 154 sucks the air through lint screen 110 , which removes dirt, fluff and other materials from the air so that vent 134 does not become clogged.
[0029] Dryer 100 also includes vents 136 that allow air to flow into drum 104 . Vents 136 may use small openings to keep foreign objects and materials out of dryer 100 . Wheel 140 is placed between vents 136 and drum 104 . Heating element 135 heats the air as it enters drum 104 in order to dry article 102 . Heating element 135 may be a heater or other device known in the art for heating forced air. Heating element 135 also may be referred to as the primary heating element of dryer 100 . Temperatures attainable by heating element 135 may vary according to the desired operation of dryer 100 , and may vary as set by controls 106 .
[0030] Wheel 140 includes compartments filled with silica gel pellets 144 . Alternatively, other silica gel products may be used in conjunction with wheel 140 . Further, other desiccants may be used with wheel 140 . Silica gel pellets 144 act like salt in removing water or moisture from incoming air. The removal, in turn, reduces the vapor pressure of the incoming air, which increases the drying capability of the air. Each pellet includes a strong positive end and strong negative end in its silica molecules. Because the water molecule also acts like a polar molecule, the water in the incoming air is attracted chemically to the silica gel. Thus, the grains of water vapor are reduced in the volume of air coming into dryer 100 .
[0031] The air flows through wheel 140 at portion 142 . Portion 142 includes those parts of wheel 140 having silica gel pellets 144 that remove water from air. Because some of the water vapor of the incoming air will attach to pellets 144 , the air flowing into drum 104 is lower in vapor pressure to dry article 102 in a more efficient and timely manner. Conventional clothes dryers use the vapor pressure of the air outside dryer 100 , which may not be very suitable for drying articles, such as clothes or towels. The moisture of air within a home, for example, may range from 45 to 110 grains/lb. The vapor pressure of the air being sucked into dryer 100 for heating by heating element 135 determines the time period for article 102 to dry. For example, air having vapor pressure of 110 grains/lb will not dry article 102 as fast as would air having grains of less than 45 grains/lb.
[0032] If the vapor pressure of the incoming air is reduced, then article 102 dries faster. The drying process consumes fewer resources because less energy is needed to evaporate water from article 102 . For example, if the vapor pressure of the incoming air is reduced down to about 10 to 40 grains/lb, then article 102 would have a reduced average drying time. Thus, less energy needs to be supplied to heating element 135 and less power to rotate drum 104 according to the disclosed embodiments.
[0033] As shown in FIG. 1 , portion 142 of wheel 140 is positioned to receive the incoming air shown by inlet air path 150 . Inlet air path 150 represents all the incoming air through vents 136 . Inlet air path 150 also includes air from other parts of dryer 100 , such as the front or sides, and is not limited to air flowing through vents 136 . Inlet air path 150 also flows through portion 142 and heating element 135 into drum 104 .
[0034] The air within inlet air path 150 reacts with pellets 144 housed in wheel 140 to remove moisture and water vapor, which, in turn, lowers the vapor pressure of the air prior to heating. Portion 142 houses these pellets. Preferably, portion 142 takes up over half the area of wheel 140 so that most of pellets 144 are reacting with the incoming air. More preferably, portion 142 represents about three quarters (¾) of the surface area of wheel 140 .
[0035] Portion 146 of wheel 140 is positioned by vent 134 to be exposed to air flowing from drum 104 to duct 130 . Outlet air path 152 represents the air expelled from drum 104 via vent 134 . Outlet air path 152 flows through portion 146 . Preferably, portion 146 is a lower part of wheel 140 .
[0036] The air within outlet air path 152 may regenerate pellets 144 within portion 146 . The pellets within portion 146 absorb the heat from outlet air path. Outlet air path 152 includes an air stream with hot air that flowed through heating element 135 and drum 104 . Outlet air path 152 bums off water vapor from pellets 144 within portion 146 that was absorbed in portion 142 from the air in inlet air path 150 . The hot air breaks the polar bond attraction between the silica pellet and water vapor molecule. Thus, outlet air path 152 dries out portion 142 of wheel 140 . By doing this procedure, pellets 144 can absorb more water vapor when they are moved back to position 142 .
[0037] The desiccant used within wheel 140 also adds to the efficiency of the drying process by recouping or retaining heat within wheel 140 . A percentage of the hot air stream of outlet air path 152 used to burn water off pellets 144 in portion 146 is retained or stored in those pellets, which reacts with the air of inlet air path 150 going through portion 142 prior to flowing through heating element 135 . Thus, the disclosed embodiments deliver air having reduced vapor pressure to article 102 in drum 104 to evaporate more water or moisture.
[0038] Dryer 100 also includes sensors or other information gathering devices to indicate temperatures, vapor pressure, parameter status, air flow and the like. This information may be forwarded to a processor 170 . Processor 170 controls operations of dryer 100 and is coupled to controls 106 and other features. Processor 170 may execute steps or commands within a memory coupled to the processor.
[0039] Sensor 158 may be located in the vicinity of inlet air path 150 to determine the temperature of air flowing into drum 104 . Based on the need of drum 104 , processor 170 can adjust heating element 135 to a desired temperature so that the air in inlet air path 150 enters drum 104 at the desired temperature. Sensor 158 also may detect moisture in the air of inlet air path 150 to determine whether wheel 140 is absorbing water vapor from inlet air path 150 .
[0040] For example, sensor 158 detects a high level of vapor pressure, or a large amount of moisture, in the incoming air, and this indicates more water vapor in the air than desired. Thus, processor 170 commands wheel 140 to turn to place the saturated pellets 144 into portion 146 for reducing the vapor pressure. Pellets 144 that are located in portion 146 are moved to portion 142 because they are dried out and more absorbent than those pellets in use. The move to position 142 allows the dry pellets to absorb the moisture from air within inlet air path 150 . Wheel 140 may be turned using a rotor coupled to a motor or power source that rotates an attached belt. This feature of the present invention is disclosed in greater detail below.
[0041] Sensors may also determine status for other areas, such as door 112 being opened. The sensors may comprise any known device used to determine temperature, vapor pressure or other parameters from an environment, especially air. In a basic configuration, sensors 156 and 158 are thermometers that simply relay a temperature reading. Alternatively, sensors 156 and 158 determine vapor pressure, air speed, humidity, force and the like of the air flowing over the respective sensor. Sensors 156 and 158 provide valuable feedback on operating dryer 100 and preventing injury to a user or article. A blast of hot air through door 112 could harm a user, as well as ruining article 102 due to overexposure to heated air.
[0042] For example, sensor 158 could indicate a start time to processor 170 for drum 104 to operate. After the time period, sensor 158 takes a reading at inlet air path 150 to make sure heating element 135 and dryer 100 are operating correctly. Sensor 156 is located in vent 134 and may serve the same purposes as sensor 158 by detecting vapor pressure, temperatures, air flow and the like. Sensor 156 may determine the vapor pressure or moisture in the outgoing air, and if it is saturated. If the air includes too much moisture or a high level of vapor pressure, then settings to dryer 100 and, specifically, wheel 140 may be adjusted accordingly.
[0043] Dryer 100 also includes a small door 160 to opening 162 . Opening 162 accommodates dryer sheets, fabric softener, detergent, and the like placed into drum 104 .
[0044] FIG. 2 depicts another dryer 200 having a different configuration incorporating desiccant wheel 140 according to the disclosed embodiments. Desiccant wheel 140 is similar to the wheel disclosed above, but is shown in dryer 200 , which is configured differently than dryer 100 of FIG. 1 . Thus, desiccant wheel 140 performs the same function as disclosed above in removing moisture from incoming air and lower the vapor pressure of air entering dryer 200 . In this configuration, however, the lower part of wheel 140 receives hot air from heating element 212 instead of moist warm air within an outlet air path. Unless otherwise indicated, dryer 200 includes the same components as dryer 100 disclosed above.
[0045] Dryer 200 differs from dryer 100 in several ways. For example, dryer 200 includes an incoming intake air stream 206 that flows into air intake 202 . Preferably, air intake 202 is located on the side of dryer 200 , and away from vents 136 that brings in inlet air path 150 . Air intake 202 may be any passage that allows air into dryer 200 , preferably with a screen or filter to keep out dust and debris. Once inside air intake 202 , air stream 206 is pulled by intake fan 210 to heating element 212 . Fan 210 is placed in dryer 200 in addition to fan 154 . Preferably, fan 210 is about ¼ th to ⅓ rd the size of fan 154 . Fans 154 and 210 may draw power from the same source.
[0046] Heating element 212 applies heat to intake air stream 206 to generate heated air stream 214 . Heated air stream 214 flows through desiccant wheel 140 . The hot air of heated air stream 214 regenerates desiccant wheel 140 . Thus, dryer 200 differs from dryer 100 in that the moist, warm air from drum 104 is diverted to the outside through vent 134 and not to desiccant wheel 140 . Instead, drier, heated air in the form of heated air stream 214 is applied to desiccant wheel 140 . The heated air in air stream 214 removes moisture from, for example, the pellets in desiccant wheel 140 . The energy in the heated air is used to break the bonds of the water molecules from the desiccant material within wheel 140 . As desiccant wheel 140 rotates back into position with inlet air path 150 , its pellets are more moisture absorbent because the heated air from heating element 212 dried the pellets.
[0047] After flowing through desiccant wheel 140 , heated air stream 214 joins an outlet air stream within outlet air path 152 . As disclosed above, outlet air path 152 carries moisture and air from article 102 and drum 104 to the outside. Moist heated air stream 220 flows into vent 134 . Fan 154 draws air stream 220 through vent 134 . Air stream 220 merges with the air coming from the regeneration of desiccant wheel 140 , or air stream 214 . Thus, the air streams for of drying article 102 and regenerating desiccant wheel 140 are kept separate from any intake air heading towards heating element 135 . This configuration results in enhanced drying efficiency for dryer 200 .
[0048] By orienting the air streams as shown in FIG. 2 , dryer 200 may eliminate lint flowing through desiccant wheel 140 . Lint going through desiccant wheel 140 would reduce efficiency of absorbing moisture from the air in inlet air path 150 that becomes air stream 230 flowing into heating element 135 . In this embodiment, lint within air stream 220 goes into outlet air path 152 and bypasses desiccant wheel 140 . This configuration prevents lint from entering the pellets or other water-absorbent material within wheel 140 .
[0049] By separating heating element 212 and heating element 135 , dryer 200 places the heat and energy in the position to result in a more efficient process without increasing heating capacity. For example, a standard heating element having a capability of about 17,000-22,000 British thermal unit/hour (Btu/hr) may be split into two parts. The majority of the total heating capacity of about 12,000-16,000 Btu/hr will stay in the air stream going into drum 104 , or air stream 232 . A small portion of the heating capacity of around 5,000-6,000 Btu/hr will be used to regenerate desiccant wheel 140 as shown by heating element 212 . The higher the temperature to regenerate wheel 140 , then the better the conditions for drying article 102 .
[0050] The creation of heated air stream 214 separate from moist air stream 220 also reduces the vapor pressure of the air used to regenerate desiccant wheel 140 . A lower vapor pressure facilitates drying within pellets 144 . Heating element 212 heats air stream 206 sucked into dryer 200 from the room or outside, and does not use moist air stream 220 . The hot air dries the pellets within desiccant wheel 140 , as opposed to moist air such as that from air stream 220 . Thus, the ggp of water will be reduced in air streams flowing into drum 104 because the water removal capabilities of desiccant wheel 140 are improved using heated air stream 214 .
[0051] For example, the gpps used in the embodiment disclosed by FIG. 1 may be around 150-200 gpp. Using the configuration disclosed by FIG. 2 may result in using only 40-90 gpp to regenerate the pellets or applicable desiccant materials. Thus, the embodiments disclosed by FIG. 2 may result in substantial savings in terms of energy needed to keep desiccant wheel removing water from the outside air efficiently. The embodiments disclosed by FIG. 2 , therefore, reduce drying time and the energy needed to dry article 102 by using the configuration shown.
[0052] FIG. 3 depicts a flowchart for drying an article in a dryer according to the disclosed embodiments. The flowchart shows steps on drying an article using an intake air stream from outside the building housing the dryer and another air stream taken from the room or vicinity of the dryer. Reference is made to features of FIG. 2 where appropriate.
[0053] Step 302 executes by activating intake fan 210 to suck in air through intake 202 . Step 304 executes by creating intake air stream 206 from the air sucked into dryer 200 . As disclosed above, air stream 206 preferably comes from air in the vicinity of dryer 200 . Step 306 executes by heating air stream 206 .
[0054] Step 308 executes by flowing the heated air from into desiccant wheel 140 , as shown by air stream 214 . Step 310 executes by regenerating the desiccant in wheel 140 using the hot air to remove moisture and water molecules. Because air stream 214 is hot, dry air, the water removal properties are greater than using outlet air stream 220 . Following step 310 , step 316 may execute, as disclosed in greater detail below. Step 312 executes by combining the air stream flowing from wheel 140 into outlet air stream 220 such that all the moist air is taken away from drum 104 and wheel 140 .
[0055] Steps 314 - 26 disclose the general drying process for dryer 200 . These steps may execute in conjunction with steps 302 - 12 such that dryer 200 does not wait on either group of steps before executing the other. Further, both groups of steps may execute concurrently.
[0056] Step 314 executes by generating air within inlet air path 150 from outside the structure housing dryer 200 . Preferably, the air stream within inlet air path 150 includes air from outside a house. Step 316 executes by positioning desiccant wheel 140 with desiccant best ready to absorb water molecules from the air flowing through wheel 140 . Wheel 140 may be moved according to a set time period, such as every 5 seconds, or upon instruction from dryer 200 . Thus, once the desiccant in wheel 140 is dried out, or regenerated, that portion of wheel 140 moves into alignment with inlet air path 150 . As disclosed above, wheel 140 may be moved by instruction, a sensor reading indicating conditions desire wheel 140 to be moved, or according to a time period.
[0057] Step 318 executes by flowing air from inlet air path 150 through desiccant wheel 140 . Water molecules, or grains of water in the air, are removed by the materials in desiccant wheel 140 . Thus, step 320 executes by removing water from inlet air path 150 to generate dry air stream 230 . Step 322 executes by heating dry air stream 230 and generating heated air stream 232 . Because of the low water vapor provides better conditions for drying articles, such as clothes, the present configuration of the disclosed embodiments improves drying efficiency.
[0058] Step 324 executes by cycling the air from heated air stream 232 through drum 104 . The air mixes and interacts with article 102 to remove moisture and water. Once the air is heavy with moisture, outlet air stream 220 is generated in step 326 . Outlet air stream 220 includes debris, moisture and air from drum 104 . Step 326 returns control of the flowchart to step 312 to combine the two outlet air flows shown in FIG. 2 . Step 328 executes by expelling the combined air from dryer 200 .
[0059] Thus, the disclosed embodiments of the present invention includes a dryer having different configurations to enhance moisture removal from incoming air. The disclosed embodiments include a wheel having a desiccant that rotates to different positions so that different portions of the wheel in the path of incoming and outgoing air. Further, the disclosed embodiments take advantage of the existing heating element in a dryer to enhance the incoming air and lower vapor pressure.
[0060] The disclosed embodiments are preferably used in open system dryers that have air brought in from outside the dryer. Thus, the air from the environment surrounding the dryer may include saturated or air having a high vapor pressure. The disclosed embodiments help to lower the vapor pressure of the incoming air using the wheel and its desiccant. Thus, no matter what the air is like outside of the dryer, the disclosed embodiments can lower the vapor pressure to a specified, acceptable level. This level is maintained because the desiccant material within the wheel is dried out by a separate air stream, or the drying ability of the desiccant material is regenerated.
[0061] The disclosed embodiments also are applicable to other drying processes beyond contemporary dryers. For example, a desiccant wheel may be set up to dry out a room or enclosed space of a building having severe moisture damage. Air is pumped, or forced, through an upper portion of the wheel prior to entering the room so as to lower the vapor pressure of the air within the room. Air also is forced out of the room to remove moisture or water that has evaporated within the room to an outside environment. Much like the outgoing air path disclosed above, this outgoing air serves to transfer heat or energy to the wheel and to regenerate the moisture removal capabilities of the wheel.
[0062] The disclosed embodiments of the present invention, however, are applicable to dryers in a household or laundry setting, where air is drawn from and returned to the outside environment. The present invention, however, is not limited to these dryers and may be applicable to any situation where an article needs to be dried using forced air. The air is heated and the moisture removed by the desiccant wheel. The vapor pressure of the incoming air is lowered to enhance moisture removal.
[0063] It will be apparent to those skilled in the art that various modifications and variations can be made in the disclosed embodiments of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention covers the modifications and variations of the embodiments disclosed above provided that they come within the scope of any claims and their equivalents. | A dryer and a drying apparatus attachable to a dryer are disclosed. A wheel having desiccant material is located in line and in close proximity with a heating element. The wheel includes a first portion positioned in an inlet air path and a second portion positioned in an outlet air path. The desiccant material removes water molecules from air within the inlet air path, and lowers the vapor pressure of the incoming air. In the outlet air path, heated air flows through the second portion to transfer energy to the desiccant material. The wheel rotates to change the desiccant material within the portions. | 3 |
BACKGROUND OF THE INVENTION
This invention relates to a sewing and stacking apparatus for stitching a folded tape on a series of sewing mediums such as crotch panels of knitted or woven men's briefs, cutting the folded tape and stacking the sewing mediums.
As shown in FIG. 1, a men's brief comprises right and left front panels A and B, a rear panel C and a crotch panel 1. The hems of the above panels which require reinforcement, such as the hem of the crotch panel 1 defining the front slit, have a folded tape 2 stitched thereon.
As shown in FIG. 2, the folded tape 2 is stitched on upper portions of a plurality of crotch panels 1 which are arranged appropriately apart from each other. The folded tape 2 is formed by folding a lengthy cloth along two or more lines running in parallel in a longitudinal direction thereof in the manner shown in FIG. 3. In this specification, the lengthy cloth is folded along two lines into two side portions L and N and a central portion M; and the three portions are stacked in such a manner that the side portion N is interposed between the side portion L and the central portion M. Each crotch patch 1 is inserted between the side portion L and the central portion M, wherein the folded tape 2 is stitched on the crotch panel 1 with two to four pairs of threads T.
Conventionally, after the folded tape 2 is stitched on the crotch panels 1 by a conventional sewing machine as shown in FIG. 4, the folded tape 2 is cut manually and the separated crotch panels 1 are laminated one after another again manually to be assembled with the other panels A through C.
The above conventional method, by which stitching, cutting and stacking are done separately and the last two processes are left to manual work, contributes an extreme inefficiency of the whole process from stitching to stacking.
SUMMARY OF THE INVENTION
Accordingly, this invention has an object of offering a sewing and stacking apparatus for enhancing the efficiency of the procedure from stitching to stacking.
Another object of this invention is to offer a sewing and stacking apparatus for carrying out stitching, cutting and stacking automatically and continuously.
The above objects are fulfilled by a sewing and stacking apparatus, comprising a sewing unit for stitching a folded tape on a series of sewing mediums of an identical shape and size arranged appropriately apart; a transporting unit for transporting the sewing mediums having the folded tape stitched thereon; a detecting unit for detecting that one of the sewing mediums reaches a specified position; a cutting unit for cutting the folded tape at a specified point when the detecting unit detects that the above one of the sewing mediums reaches the specified position, the specified point being between the above one of the sewing mediums and another sewing medium adjacent thereto; and a stacking unit for stacking the sewing mediums separated from each other by the cutting unit.
The folded tape may be a lengthy cloth folded into two side portions and a central portion along two lines running in parallel in a longitudinal direction thereof and in the manner that one of the side portions is interposed between the other side portion and the central portion, and the folded tape may be stitched on the sewing mediums with the sewing mediums being interposed between the above two side portions.
The sewing unit may be a sewing machine having two needles.
The transporting unit may comprise a first pair of belts and a second pair of belts.
The first pair of belts may be provided along the cutting unit and the second pair of belts are provided between the first pair of belts and the stacking unit.
The above apparatus may further comprise a guiding plate provided below the cutting unit.
The cutting unit may comprise a first pair of lower and upper blades, a second pair of lower and upper blades, and a driving member for closing each pair of the blades; the first and the second pairs of blades being respectively disposed at an upstream position and a downstream position, which is a little farther from the upstream position than a length of each sewing medium in a transporting direction thereof, the lower blades of the first and the second pairs being disposed on slits of the guiding plate.
The detecting unit may comprise first and second photosensors provided on a transporting path of the sewing mediums in the vicinity of the first and the second pairs of lower and upper blades, respectively.
The first photosensor may be connected to a detecting circuit for detecting a leading end of each sewing medium, and drives the first pair of blades in accordance with the detection result of the detecting circuit; and the second photosensor is connected to a detecting circuit for detecting a rear end of each sewing medium, and drives the second pair of blades.
The second pair of belts may transport while interposing therebetween the sewing mediums which have passed through the first pair of belts and are twisted for gradually twisting 90° downward the sewing mediums.
The stacking unit may comprise a stacking table and a pivotal plate for slapping down the sewing mediums from the second pair of belts, the sewing mediums having passed therethrough, and guiding the sewing mediums onto the stacking table.
The cutting unit may further comprise a collecting unit for collecting cut-off portions of the folded tape, the collecting unit being provided in the vicinity of and downstream from the second pair of blades.
The above apparatus may further comprise a guiding unit for guiding the folded tape between the sewing unit and the guiding plate.
The above apparatus may further comprise an air blowing nozzle for blowing air to keep the sewing mediums horizontal, the nozzle being provided along the guiding unit; and an assisting plate for guiding the sewing mediums which are kept horizontal by the air blowing nozzle to the first pair of belts.
According to the present invention, sewing mediums having a folded tape stitched thereon are transported to a cutting unit by a transporting unit. When a detecting unit detects that one of the sewing mediums has reached a specified cutting position, the cutting unit cuts the folded tape at a specified point between the above one sewing medium and the adjacent sewing medium. The sewing mediums are further transported to a stacking unit by the transporting unit, wherein the sewing mediums are stacked at a specified position. Consequently, the whole process from stitching to stacking is carried out continuously with no manual labor, which contributes to a great enhancement in efficiency.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings which illustrate a specific embodiment of the invention. In the drawings:
FIG. 1 is a front view of a men's brief;
FIG. 2 is a view of the folded tape 2 stitched on a plurality of crotch panels 1;
FIG. 3 is an enlarged view of a portion of the crotch panel 1 having the folded tape 2 stitched thereon;
FIG. 4 is a side view of a conventional sewing machine for stitching the folded tape 2 on the crotch panel 1;
FIG. 5 is a perspective view of a sewing and stacking apparatus according to this invention;
FIG. 6 is a perspective view of a cutting unit 5;
FIG. 7 is a side view of the cutting unit 5 and the vicinity thereof;
FIG. 8 is a perspective view of a guide 52 of the cutting unit 5;
FIG. 9 is a cross sectional view of an essential part of the guide 52;
FIG. 10 is a view of a modified example of the guide 52;
FIG. 11 is a view illustrating how the folded tape 2 is cut;
FIG. 12 is a perspective view of an essential part of the second belt unit 42;
FIG. 13 is a side view of a stacking unit 7;
FIGS. 14a and 14b are circuit diagrams of the cutting operation; and
FIGS. 15a through 15e are waveforms indicating the operations of the circuits in FIGS. 14a and 14b.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 5 shows a perspective view of a sewing and stacking apparatus as an embodiment of this invention.
The sewing and stacking apparatus comprises a sewing machine 3 for stitching the folded tape 2 on a crotch panel 1, a cutting unit 5 for cutting off an unnecessary portion of the folded tape 2, a stacking unit 7 for stacking the crotch panels 1, a transporting unit for transporting the crotch panel 1 through the cutting unit 5 and further to the stacking unit 7, and a detecting unit 6 (FIG. 6).
Although any type of sewing machine may be employed as the sewing machine 3, it is desirable to use the one which has two, three or four needles in order to stitch strongly. In this embodiment, the sewing machine 3 has two needles for the sake of simpler figures and easier explanation.
As shown in FIGS. 5, 7 and 8, the cutting unit 5 comprises a cutting table 51, a guide 52 for guiding the looped tape 2 to the cutting table 51, two cutters 54 and 55 disposed at upstream and downstream positions on the cutting table 51, and air cylinders 56a and 56b for driving the cutters 54 and 55.
As shown in FIG. 8, the guide 52 comprises a main body 52a having a shallow groove-shaped cross section, at least one leaf spring 53 for pressing the tape 2 on the main body 52a, an air blowing nozzle 52b for blowing air if necessary to keep the crotch panel 1 nearly horizontal (FIG. 9), and an assisting plate 52c for guiding the crotch panel 1 to the transporting unit 4 keeping it horizontal.
The leaf spring 53 may be replaced with a roller. The main body 52a may have a rectangular cross section with a corner opened as indicated by 52a' shown in FIG. 10, in which case, the leaf spring 53 is unnecessary.
As shown in FIG. 6, the cutter 54 comprises a lower blade 54a and an upper blade 54b, and the cutter 55 comprises a lower blade 55a and an upper blade 55b. The lower blades 54a and 55a define slits of the cutting table 51, and the upper blades 54b and 55b are pivotally supported on the cutting table 51. The upper blades 54b and 55b are to be pivoted down by the air cylinders 56a and 56b, whereby to cut the looped tape 2.
The cutting table 51 has a pair of reflective photoelectric tubes 6a and 6b buried therein in the vicinity of the cutters 54 and 55, the tubes 6a and 6b forming the detecting unit 6. As shown in FIG. 11, the cutter 54 is controlled to cut the folded tape 2 at position X in the vicinity of the rear end 1b of the crotch panel 1 when the rear end 1b is revealing the photoelectric tube 6a and the cutter 55 is controlled to cut the folded tape 2 at position Y in the vicinity of the leading end 1a of the crotch panel 1 when the leading end 1a is covering the photoelectric tube 1b.
As shown in FIG. 6, the cutting unit 5 is further equipped with a collecting unit 57 for collecting the unnecessary portion of the folded tape 2 which has been cut off by the cutters 54 and then 55. The collecting unit 57 comprises an absorbing pipe 57a for absorbing the cut-off portion of the folded tape 2, the pipe 57a being extended downward from an opening 57b of the cutting table 51. The pipe 57a is connected to a vacuum absorbing unit (not shown).
As shown in FIG. 5, the transporting unit 4 comprises a first belt unit 41 provided along the cutting table 51 and a second belt unit 42 provided downstream from the cutting table 51 in a transporting direction.
The first belt unit 41 comprises a pair of endless belts 41a and 41b which are opposed to each other on the same plane as an upper surface of the cutting table 51. The endless belt 41a is extended between a driving pulley 41c and an idle pulley 41e in a substantial ellipse. The endless belt 41b is extended between a driving pulley 41d and an idle pulley 41f in a substantial ellipse. The pulleys 41c, 41d, 41e and 41f are rotatable around axes thereof. The endless belts 41a and 41b are rotated in parallel but in opposite directions to each other at a speed substantially the same as the average sewing speed of the sewing machine 3.
The second belt unit 42 comprises a pair of opposing endless belts 42a and 42b. The endless belt 42a is extended between an idle pulley 42c and a driving pulley 42f, and the endless belt 42b is extended between an idle pulley 42d and a driving pulley 42e. The idle pulleys 42c and 42d are provided in the vicinity of the cutting table 51 and rotatable around horizontal axes thereof, and the driving pulleys 42e and 42f are provided downstream from the pulleys 42c and 42d and rotatable around vertical axes thereof. Guiding rollers 42g and 42h (illustrated in detail in FIG. 12) are provided a little downstream from the pulleys 42c and 42d for turning the horizontal belts 42a and 42b vertical. Guiding pulleys 42i and 42j are provided further downstream for guiding the belts 42a and 42b onto a central line of the pulleys 42c and 42d.
The stacking unit 7 comprises a pivotal plate 71 disposed below the second belt unit 42 and pivotal between a vertical position and a horizontal position (FIG. 13) and a stacking table 72 disposed below the pivotal plate 71 which is at the horizontal position. The stacking table 72 may be a simple table In this embodiment, however, the table 72 comprises a pair of pulleys 72a and 72b and an endless belt 72c extended in a substantial ellipse between the pulleys 72a and 72b.
The sewing and stacking apparatus having the above construction is operated in the following way.
The folded tape 2 is guided below tips of needles of the sewing machine 3 by a guiding member 3a, wherein the folded tape 2 holds the upper portions of the crotch panels 1 (FIG. 3; in series and is stitched thereon.
Then, the folded tape 2 with the crotch panels 1 is transported to the cutting unit 5 in the following manner. The folded tape 2 is carried onto the cutting table 51 through the guide 52, and simultaneously the crotch panels 1 are transported to the first belt unit 41 in a horizontal state and interposed between the endless belts 41a and 41b. The tape 2 and the crotch panels 1 advance side by side. Before reaching the guide 52, the tape 2 is transported in a U shape so that the force of the first belt unit 41 may not influence the movement of the needles of the sewing machine 3.
When the leading end 1a of one of the crotch panels 1 is covering the photoelectric tube 6b with the rear end 1b of the crotch panel 1 revealing the photoelectric tube 6a, the cutters 54 and 55 cut the looped tape 2 at positions X and Y in the vicinity of both of the ends 1a and 1b in accordance with the principle described later. As the crotch panels 1 advance on the cutting table 51 one after another, the above cutting operation is repeated. The cut-off portions of the looped tape 2 are absorbed into the absorbing pipe 57a.
After that, the crotch panels 1 are carried toward the stacking unit 7 one after another with the upper portions thereof interposed between the endless belts 42a and 42b. Each crotch panel 1 is twisted 90° by the pulleys 42g and 42h, whereby the crotch panel 1 is hung vertically. When the pivotal plate 71 is pivoted down horizontally, the crotch panel 1 is released from the endless belts 42a and 42b and is slapped down flat on the laminating table 72. The crotch panels 1 are laminated on the stacking table 72 one after another with the upper portions thereof being hung downward. When a certain number of crotch panels 1 are stacked, the endless belt 72c is rotated, whereby another series of crotch panels 1 are stacked on another portion of the endless belt 72c.
Hereinafter, the principle of cutting the folded tape 2 will be described in detail.
FIGS. 14a and 14b show circuits for operating the cutters 54 and 55 in accordance with the detection results of the photoelectric tubes 6a and 6b, respectively. 101a and 101b are Schmitt trigger circuits for shaping signals; 102a and 102b are one-shot multivibrators each having a specified time constant; 103a and 103b are operating valves for expanding the air cylinders 56a and 56b, respectively; and 104 is an inverter.
The photoelectric tubes 6a and 6b, which are of the reflective type, each output a signal when detecting the crotch panel 1 thereon. The signal from the tube 6a is shaped by the Schmitt trigger circuit 101a, and the signal from the tube 6b is shaped by the Schmitt trigger circuit 101b. Provided the Schmitt trigger circuit 101a has an output waveform as shown in FIG. 15a and that the Schmitt trigger circuit 101b has an output waveform as shown in FIG. 15c, that means the leading end 1a passes on the photoelectric tube 6a at time t 1 and the rear end 1b passes on the photoelectric tube 6b at time t 2 . Since the signal from the Schmitt trigger circuit 101a is directly sent to the one-shot multivibrator 102a, the one-shot multivibrator 102a outputs a signal as shown in FIG. 15b. Accordingly, the operating valve 103a is operated for the duration of a time constant t 1 starting from time t 1 , through which time the air cylinder 56a is expanded, whereby the upper blade 54b is pivoted down to cut the folded tape 2.
Since the signal from the Schmitt trigger 101b is reversed by the inverter 104 to be as shown in FIG. 15d before entering the one-shot multivibrator 102b, the one-shot multivibrator 102b outputs a signal as shown in FIG. 15e. Accordingly, the operating valve 103b is operated for the duration of t 2 starting from time t 2 , through which time the air cylinder 56b is expanded, whereby the upper blade 55b is pivoted down to cut the folded tape 2.
According to the above construction, the folded tape 2 stitched on a series of crotch panels 1 by the sewing machine 3 is automatically transported by the first belt unit 41 to the cutting unit 5, wherein the tape 2 is cut. The tape 2 with the crotch panels 1 is further transported by the second belt unit 42 to the stacking unit 7 automatically, wherein the crotch panels 1 are stacked one after another. In this way, the whole procedure from stitching to stacking is carried out quite efficiently.
Although the crotch panel 1 is used as the sewing medium in the above embodiment, the sewing and stacking apparatus according to this invention is used for any sewing medium of any shape and any material.
Although the present invention has been fully described by way of an embodiment with references to the accompanying drawings, it is to be noted that various changes and modifications will be apparent to those skilled in the art. Therefore, unless such changes and modifications depart from the scope of the present invention, they should be construed as being included therein. | A sewing and stacking apparatus, comprising a sewing unit for stitching folded tape on a series of sewing mediums of an identical shape and size arranged appropriately apart; a transporting unit for transporting the sewing mediums having the folded tape stitched thereon; a detecting unit for detecting that one of the sewing mediums reaches a specified position; a cutting unit for cutting the folded tape at a specified point when the detecting unit detects that the above one of the sewing mediums reaches the specified position, the specified point being between the above one of the sewing mediums and another sewing medium adjacent thereto; and a stacking unit for stacking the sewing mediums separated from each other by the cutting unit. | 3 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of International Application PCT/EP2008/008866, (International Publication No. WO 2010/045951 A1), filed Oct. 20, 2008, which is hereby incorporated by reference in its entirety.
TECHNICAL FIELD
[0002] The invention is directed at the building up of objects and, in particular, to the building up of objects that are intended to be used for dental restorations.
BACKGROUND OF INVENTION
[0003] CAD-CAM technologies have been established in the dental sector for some time and have taken the place of the traditional manual crafting of tooth replacements. However, the methods customary today for producing ceramic dental restoration elements by removing material have several disadvantages, which cannot be improved with reasonable expenditure from economic aspects by the current state of the art. In this connection, building-up methods of production that are known under the term “rapid prototyping” can be considered, in particular stereolithographic methods in which a newly applied layer of material is respectively polymerized in the desired form by position selective exposure, whereby the desired body is gradually produced by shaping in layers in its three-dimensional form, which results from the succession of the layers applied.
[0004] With respect to ceramic-filled polymers, WO 98/06560, which is hereby incorporated by reference, should be mentioned in particular. In this case, a ceramic slip is exposed by way of a dynamic mask (light modulator), whereby a three-dimensional body is intended to be gradually built up. In the case of the method described, the ceramic slip is exposed from above on a build platform. In the case of such exposure from above, after each exposure a new thin layer of material must be applied with the aid of a doctor blade (typically with a layer thickness which lies between 10 and 100 μm). When using materials of relatively high viscosity, as ceramic-filled resins are, it is only with difficulty, however, that such thin layers can be applied in a reproducible manner.
[0005] In the prior art, there are also known techniques, at least for photomonomers without ceramic filling, in which the exposure takes place from below through the bottom of a vat, which is formed by a transparent film, sheet or sheet with an elastomeric surface (for example of silicone or fluoroelastomer). Above the transparent film or sheet there is a build platform, which is held at a settable height above the film or sheet by a lifting mechanism. In the first exposure step, the photopolymer between the film and the build platform is polymerized in the desired form by exposure. When the build platform is raised, the polymerized first layer becomes detached from the film or sheet and liquid monomer flows into the space created. The object polymerized in layers is created by successive raising of the build platform and selective exposure of the monomer material that has flowed in. A device suitable for applying this method is described for example in DE 199 57 370 A1, which is hereby incorporated by reference. A similar procedure is described in DE 102 56 672 A1, which is hereby incorporated by reference, which however likewise relates to unfilled polymers.
[0006] In the processing of ceramic-filled photopolymers, the following problems arise in comparison with the processing of unfilled photopolymers:
[0007] The green strength of the polymerized objects is significantly lower (less than 10 MPa) than the strength of an unfilled polymer (typically about 20 to 60 MPa). As a result, the ceramic-filled photopolymer object can withstand significantly less mechanical loading (for example when the last-formed layer is detached from the sheet or film through which exposure was performed from below).
[0008] The high proportion of ceramic particles causes pronounced light diffusion, and the depth of penetration of the light that is used is significantly reduced. Associated with this is non-uniform polymerization in the z direction (direction of radiation) in the case of layer thicknesses of more than 20 μm. The small depth of penetration also makes it difficult to achieve reliable bonding of the first layer directly on the build platform. In the case of ceramic-filled monomer material, however, it cannot be ensured that the initial starting layer is sufficiently thin (for example less than 75 μm). Consequently, a reproducible bonding force on the build platform could not be ensured even with very long exposure of the first layer.
[0009] In comparison with unfilled photopolymers, ceramic-filled polymerizable materials are significantly more viscous. This imposes increased requirements on the exposure mechanism that is used. In particular, the time that is required for ceramic-filled photopolymer to flow in after raising of the build platform may be considerably longer. The raising and lowering of the build platform in a highly viscous photopolymer material also imposes increased requirements to avoid detrimental effects on the component.
[0010] On account of the high basic viscosity, ceramic-filled photopolymers are more sensitive to gelling by diffused light or ambient light. Even small light intensities are sufficient to raise the viscosity of the material above the permissible limit by the polymerization taking place.
SUMMARY OF THE INVENTION
[0011] The problem addressed by the present invention is that of improving a building method and a device for processing light-polymerizable materials for building up objects, using lithographic rapid prototyping, in such a way that they allow even light-polymerizable materials of relatively high viscosity, in particular ceramic-filled photopolymers, to be processed better.
[0012] The device and method according to the independent patent claims serve for solving this problem. Advantageous embodiments of the invention are specified in the subclaims.
[0013] The invention relates to a device for processing light-polymerizable material for building up an object in layers, using lithography-based generative fabrication, for example rapid prototyping, with a build platform for building up the object, a projecting exposure unit, which can be controlled for position selective exposure of a surface on the build platform with an intensity pattern with prescribed geometry, and a control unit, which is prepared for polymerizing in successive exposure steps layers lying one above the other on the build platform, respectively with prescribed geometry, by controlling the exposure unit, in order in this way to build up the object successively in the desired form, which results from the sequence of the layer geometries.
[0014] The invention also relates to a method for processing light-polymerizable material for building up an object in layers, using a lithography-based generative fabrication technique (rapid prototyping), in which light-polymerizable material is polymerized on a build platform in a layer with prescribed geometry by exposure in an exposure area, the build platform is displaced for the forming of a subsequent layer, light-polymerizable material is newly fed onto the layer last formed, and, by repeating the previous steps, the object is built up in layers in the desired form, which results from the sequence of the layer geometries.
BRIEF DESCRIPTION OF THE FIGURES
[0015] Further advantages, details and features emerge from the following description of embodiments of the invention on the basis of the drawings, in which:
[0016] FIG. 1 shows a lateral plan view, partly in section, of a device according to the invention,
[0017] FIG. 2 shows a plan view of the device from FIG. 1 , from above,
[0018] FIGS. 3 to 5 show a partial view of the device from FIG. 1 in the region of the build platform and the vat bottom in successive working steps,
[0019] FIG. 6 shows a plan view from above of a second embodiment of the invention,
[0020] FIG. 7 shows a lateral plan view, partly in section, of the device of the second embodiment from FIG. 6 , and
[0021] FIG. 8 shows a plan view from above of a third embodiment of the device.
DETAILED DESCRIPTION OF THE INVENTION
[0022] The device according to the invention is characterized in that a further exposure unit is provided for exposing the surface area of the build platform from the side opposite from the projecting exposure unit, in that the build platform is formed such that it is at least partially transparent or translucent and in that the control unit is designed to control the further exposure unit, at least while building up the first layer, which adheres to the build platform, for exposure in the prescribed geometry, in order to achieve complete polymerization and adhesive attachment at least of the first layer to the build platform. This is of advantage in particular for light-polymerizable materials in which light is strongly absorbed or diffused, since these materials cannot be polymerized reliably and reproducibly completely by exposure exclusively from the side facing away from the build platform.
[0023] Furthermore, this complete polymerization has the effect of producing exact parallelism of the first layer with the vat bottom, which is of great significance for the optimum process of detachment of the further layers.
[0024] In a preferred embodiment, the device has at least one vat with an at least partially transparently or translucently formed bottom, into which light-polymerizable material can be filled, the build platform being held in relation to the vat bottom at a settable height above the vat bottom by a lifting mechanism. The control unit is prepared for adapting the relative position of the build platform to the vat bottom by controlling the lifting mechanism after each exposure step for a layer.
[0025] In a preferred embodiment, the projecting exposure unit is arranged below the vat bottom for the exposure of the at least partially transparent or translucent vat bottom from below; correspondingly, the further exposure unit is then arranged above the build platform, behind the side thereof that is facing away from the vat bottom, in order to expose the build platform from above.
[0026] In the lifting mechanism, and connected to the control unit, there is preferably a force transducer, which is capable of measuring the force exerted by the lifting mechanism on the build platform and sending the measurement result to the control unit, the control unit being prepared for moving the build platform with a prescribed force profile. In particular in the case of ceramic-filled light-polymerizable materials, on account of the high viscosity, great forces may occur when the build platform is moved down into or moved up out of the viscous material, caused by the viscous material being displaced from or sucked in between the build platform and the vat bottom. In order to limit the forces occurring and nevertheless allow the highest possible lowering and raising rates, which speeds up the production process as a whole, the control unit may use the lifting mechanism optimally in a force-controlled manner by force measurement.
[0027] Light-emitting diodes are preferably used in the device as the light source of the projecting exposure unit and/or of the further exposure unit. Conventionally, mercury vapor lamps have been used in the case of stereolithography processes with mask projection, which however entails disadvantages since the luminous density of such mercury vapor lamps can vary considerably over time and space, which often makes repeated calibrations necessary. It is therefore preferred to use light-emitting diodes, which show significantly lower variations in intensity over space and time. Nevertheless, in a preferred embodiment, the device is prepared for carrying out a correction or compensation of variations in intensity automatically at prescribed intervals. For this purpose, it may be provided that the exposure unit has a reference sensor, which is formed as a photosensor scanning the entire exposure area or as a CCD camera recording the entire exposure area. The control unit is prepared for operating in a calibration step by exposing the exposure area with a prescribed intensity and using the intensity pattern recorded by the reference sensor for calculating a location-dependent compensation, the application of which produces a uniform intensity in the entire exposure area.
[0028] Light-emitting diodes which emit light with different optical wavelengths are preferably used. This makes it possible to process different materials with different photoinitiators in the same device.
[0029] The projecting exposure unit and the further exposure unit are preferably designed for the emission of light with an average intensity of 1 mW/cm 2 to 2000 mW/cm 2 , in particular 5 mW/cm 2 to 50 mW/cm 2 .
[0030] The projecting exposure unit preferably has a spatial light modulator, in particular a micromirror array controlled by the control unit.
[0031] The projecting exposure unit also has at least one reference sensor, which is formed as a photosensor scanning the entire exposure area or as a CCD camera recording the entire exposure area, the control unit being prepared for operating in a calibration step by exposing the exposure area with a control signal that is homogeneous over the entire exposure area and using the intensity pattern recorded by the reference sensor for calculating a compensation mask to achieve a uniform intensity in the entire exposure area. The compensation mask delivers location-dependently in the exposure area a relationship between the signal amplitude controlling the exposure unit and the actual intensity respectively resulting from this. This allows time-dependent or permanently occurring variations of the locational intensity distribution in the exposure area to be compensated, by the projecting exposure unit being controlled by the control unit with a position dependent signal that is inverse to the compensation mask recorded in the last calibration step, so that a uniform actual intensity can be achieved in the exposure area.
[0032] In order to achieve a layer thickness of light-polymerizable material over the vat bottom that is as uniform as possible and can be prescribed as exactly as possible, the device according to the invention is preferably constructed as follows. The vat is movable in a horizontal direction with respect to the projecting exposure unit and the build platform. Arranged ahead of the exposure unit and the build platform in the direction of movement of the vat is an application device, for example a doctor blade or a roller, the height of which above the vat bottom can be set. The application device, extending with a lower edge parallel to the vat bottom, smooths the light-polymerizable material to a uniform thickness before it reaches the polymerization region between the exposure unit and the build platform.
[0033] To perform this movement between successive exposure steps, the vat may be mounted with its bottom rotatable about a central axis and be turned by a prescribed angle by a drive between successive exposure steps. The projecting exposure unit and the build platform lying above it lie offset radially outward with respect to the central axis, so that in successive exposure steps and rotational movement steps taking place in between the vat bottom is ultimately passed over in the form of a circular ring. The application device, for example a doctor blade or roller or combinations thereof, then lies ahead of the projecting exposure unit in the direction of movement, so that the exposure process takes place after the application device has acted on the layer of material. Multiple doctor blades or rollers or combinations thereof may be provided in order to have a smoothing and rolling effect on the layer. The application device may also be formed in particular by an edge of a discharge channel of the feed device, which lies at a settable height above the vat bottom.
[0034] The light-polymerizable material may, for example, be discharged from a feed device, for example a reservoir, into the vat with the partially transparent or translucent bottom, the exposure taking place from below through the transparent or translucent bottom. Between successive exposure steps for the forming of successive layers, the bottom is moved in relation to the exposure unit and the build platform. During the exposure step, the vat is stationary with respect to the exposure unit and the build platform.
[0035] By suitable choice of the size of the movement steps of the vat, strategies which allow the vat bottom to be exposed at new places each and every time can be carried out, so that adhesive attachment of the light-polymerizable material to the vat bottom caused by repeated exposure of the same place on the vat bottom can be reduced. In a rotational movement of the vat, for example, the ratio of full circle (360° to rotational angle increment is preferably not an integral number, in particular also not a rational number. Alternatively, the rotational angle increments may also be varied in a prescribed or random manner, so that the polymerization always takes place in different regions of the vat.
[0036] In a preferred embodiment, behind the region of the projecting exposure unit and the build platform there lies a wiper which can be positioned at a prescribable height above the vat bottom and is designed for renewed distribution of the material after the polymerization process. After an exposure step and after the build platform has been raised, a zone without light-polymerizable material, corresponding to the form of the layer last formed, is left behind in the layer of material on the vat bottom. This zone is filled again at the latest when it is passed by the wiper, by renewed distribution of the material on the vat bottom.
[0037] The device is preferably designed for the purpose of performing a relative tipping movement between the build platform and the vat bottom when the raising of the build platform is initiated after an exposure step, under the control of the control unit, whereby a more gentle separation of the layer of polymerized material from the vat bottom is achieved, and consequently less stress on the object.
[0038] In a preferred embodiment there are a plurality of vats, each of which is assigned a feed device for one of a plurality of light-polymerizable materials, and a drive, which, under the control of the control unit, is capable of moving one of the vats in each case in a selected prescribed sequence between the projecting exposure unit, the further exposure unit and the build platform, this movement being a linear movement in the case where multiple vats are arranged in series or a rotating movement in the case where multiple vats are arranged along a curved path, whereby layers of different materials can be built up in accordance with the selected prescribed sequence.
[0039] The feed device preferably has a receptacle for inserting a cartridge with light-polymerizable material, in order to be able in a simple way to use the light-polymerizable material that is desired for the respective building process.
[0040] The underside of the build platform is preferably provided with a structuring, for example comprising nubs, channels or grooves, which is provided in or on the lower surface itself and/or in or on a coating or film applied thereto. The at least partially transparent or translucent vat bottom is preferably formed by a film or a sheet containing a polymerization inhibitor. The build platform may, in particular, consist of a high-temperature-resistant material, preferably of zirconium oxide, aluminum oxide, sapphire glass or quartz glass.
[0041] A method according to the invention of the aforementioned type is characterized in that, at least during the polymerization of the first layer directly on the build platform, light is irradiated into the side of the build platform opposite from the side with the first layer to be polymerized, the build platform being formed such that it is transparent or translucent in the region of the exposure area in order to achieve complete polymerization and adhesive attachment at least of the first layer on the build platform.
[0042] Preferably, the light-polymerizable material on the underside of the build platform is polymerized by exposure from below, the build platform is raised in relation to a vat after each exposure step and light-polymerizable material is newly fed under the layer last formed.
[0043] Subsequently, the build platform with the layers formed on it is preferably lowered again into the newly fed light-polymerizable material, so that light-polymerizable material is displaced from the intermediate space, and the distance between the lower surface of the layer last formed and the vat bottom is set in a prescribed manner. In this way, the thickness of the layer to be formed, which corresponds to the distance between the lower surface of the layer last formed and the vat bottom, can be precisely set by mechanically precise setting of the build platform above the vat bottom.
[0044] The first layer of light-polymerizable material is preferably polymerized onto a, possibly removable, film or coating arranged on the underside of the build platform.
[0045] The displacement of the build platform preferably takes place by raising and/or lowering under force control in accordance with a prescribed force profile, i.e. the force exerted by the lifting mechanism on the build platform is limited with respect to prescribed criteria. As a result, the forces occurring, which may be considerable, particularly in the case of materials of relatively high viscosity, and could detrimentally affect the buildup of the object, can be limited while nevertheless allowing the highest possible lowering and raising rates of the build platform into and out of the light-polymerizable material, which optimizes the speed of the production process as a whole, since it is possible to work at all times with the highest speed at which detrimental effects are still avoided.
[0046] Light-polymerizable material is preferably discharged from a feed device into a vat with an at least partially transparent or translucent bottom, the exposure taking place from below through the vat bottom of an at least partially transparent or translucent form, the bottom of the vat being moved in relation to the projecting exposure unit and the further exposure unit and the build platform between successive exposures for the forming of successive layers, there being arranged ahead of the exposure units and the build platform in the direction of movement an application device, preferably a doctor blade or a roller, the height of which above the vat bottom is set in order to bring the light-polymerizable material to a uniform layer thickness.
[0047] The vat is preferably rotatably mounted and is turned by a prescribed angle about the axis of rotation between successive layer building steps.
[0048] Alternatively or in addition, the vat may be mounted such that it can be moved laterally and may be moved over a prescribed distance in the horizontal direction between successive layer building steps.
[0049] To allow the build up of objects using different materials, a plurality of different materials can be used for building up layers in a selectable sequence in successive layer building steps, by a plurality of vats, each assigned a feed device with one of the plurality of materials, being moved in a selected sequence between the projecting exposure units and the build platform, this movement being a linear movement in the case where multiple vats are arranged in series or a rotating movement in the case where multiple vats are arranged along a curved path.
[0050] In a preferred embodiment, a particle-filled, for example ceramic-filled, light-polymerizable material is used for the production of the object and the organic constituents are burned out from the finished object before the object is sintered. The particle fraction of the light-polymerizable material may preferably consist of an oxide ceramic or a glass ceramic.
[0051] The light-polymerizable material on the underside of the build platform is preferably polymerized by exposure from below, after which the build platform is raised in relation to a vat for the light-polymerizable material after each exposure step and light-polymerizable material is newly fed under the layer last formed. In this case, the first layer of light-polymerizable material may be polymerized onto a removable film or coating arranged on the underside of the build platform.
[0052] The object to be produced by the method according to the invention may be, for example, a green blank for a dental restoration, in which case the light-polymerizable material may be, for example, a ceramic-filled photopolymer. The build platform preferably has a sheet of a high-temperature-resistant material, preferably of zirconium oxide, aluminum oxide, sapphire glass or quartz glass. A transparent polymer film may be adhesively attached on such a ceramic base in order to form the build platform, it being possible for the polymer film to be provided with structurings such as nubs, channels or the like on the side that comes into contact with the photopolymer, in order to achieve still better adhesive attachment of the ceramic-filled photopolymer. After the successive buildup of the green blank, the build platform with the green blank adhesively attached thereto can be removed and introduced directly into the sintering furnace. During the debinding of the component, not only the organic resin component but also the polymer film of the build platform decomposes, and after the sintering the sintered ceramic object consequently lies loosely on the sheet of the build platform and can be removed.
[0053] In the case of the method according to the invention, a plastic may preferably be used for producing the object, the object being embedded in an embedding compound after it has been produced and burned out after the embedding compound has solidified, and a different material, in particular a dental ceramic material or metal or an alloy, being forced into the cavities created in the embedding compound.
[0054] In the case of a preferred method, a dental composite may be used for the production of the object and, after it has been produced, the object may be heat-treated and subsequently polished or coated and subsequently heat-treated.
[0055] In the case of a method according to the invention, the ceramic fraction of the ceramic-filled photopolymer preferably consists of an oxide ceramic or a glass ceramic, in particular zirconium oxide, aluminum oxide, lithium disilicate, leucite glass ceramic, apatite glass ceramic or mixtures thereof.
[0056] In the case of a method according to the invention, after carrying out an exposure step with the vat stationary, the build platform is preferably raised in order to lift off the layer formed from the vat bottom. For this purpose, a slight relative tipping movement between the build platform and the vat bottom is preferably carried out, since, after the polymerization, adhesive attachment of the layer formed to the vat bottom could lead to excessive mechanical stress on the layer just formed or the entire component if it were pulled vertically upward. After the build platform has been raised, a zone without light-polymerizable material, corresponding to the form of the layer last formed, is left behind in the layer of material on the vat bottom. This zone is filled again at the latest when it is passed by the doctor blade or the roller or by an optional additional wiper, by renewed distribution of the material on the vat bottom.
[0057] The following exemplary embodiment relates to the production of a green blank for a dental restoration.
[0058] Firstly, the main components of the device are described with reference to FIGS. 1 and 2 .
[0059] In the embodiment represented in FIGS. 1 and 2 , the device has a housing 2 , which serves for accommodating and fitting the other components of the device. The upper side of the housing 2 is covered by a vat 4 , which has, at least in the regions intended for exposures, a transparent and planar vat bottom.
[0060] Provided in the housing 2 , under the vat bottom 4 , is a projecting exposure unit 10 , which can, under the control of a control unit 11 , expose a prescribed exposure area on the underside of the vat bottom 6 selectively with a pattern in the desired geometry.
[0061] The projecting exposure unit 10 preferably has a light source 15 with multiple light-emitting diodes 23 , a luminous power of approximately 15 to 20 mW/cm2 preferably being achieved in the exposure area. The wavelength of the light radiated from the exposure unit preferably lies in the range from 400 to 500 nm. The light of the light source 15 is modulated location-selectively in its intensity by way of a light modulator 17 and imaged in the resultant intensity pattern with the desired geometry on the exposure area on the underside of the vat bottom 6 . Various types of so-called DLP chips (digital light processing chips) may serve as light modulators, such as for example micromirror arrays, LCD arrays and the like. Alternatively, a laser may be used as the light source, the light beam of which successively scans the exposure area by way of a movable mirror, which may be controlled by the control unit.
[0062] Provided over the projecting exposure unit 10 on the other side of the vat bottom 6 is a build platform 12 , which is held by a lifting mechanism 14 with a carrier arm 18 , so that it can be held over the vat bottom 6 above the exposure unit 10 in a height-adjustable manner. The build platform 12 is likewise transparent or translucent.
[0063] Arranged above the build platform 12 is a further exposure unit 16 , which is likewise controlled by the control unit 11 in order, at least during the forming of the first layer under the build platform 12 , also to irradiate light from above through the build platform 12 , in order thereby to achieve dependable and reliably reproducible polymerization and adhesive attachment of the first polymerized layer on the build platform.
[0064] Also provided above the surface of the vat 4 is a feed device 8 with a reservoir in the form of an exchangeable cartridge 9 filled with light-polymerizable material. Under the control of the control unit 11 , ceramic-filled light-polymerizable material can be successively discharged from the feed device 8 onto the vat bottom 6 . The feed device is held by a height-adjustable carrier 34 .
[0065] The vat 4 is mounted rotatably about a vertical axis 22 on the housing 2 by a bearing 7 . A drive 24 , which, under the control of the control unit 11 , sets the vat 4 in a desired rotational position, is provided.
[0066] A wiper 30 , which can undertake various functions, as explained further below, may be arranged between the exposure unit 12 and the feed device 8 in the direction of rotation, at a suitable height above the vat bottom 6 .
[0067] As can be seen from FIG. 2 , lying between the feed device 8 and the exposure unit 12 , above the vat bottom 6 , is an application device 26 , here in the form of a doctor blade 26 , which can be positioned at a suitable height above the vat bottom 6 , in order in this way to smooth material that has been discharged from the feed device 8 onto the vat bottom 6 before it reaches the exposure unit 12 , in order thereby to ensure a uniform and prescribed layer thickness. Alternatively or in addition to the doctor blade, one or more rollers or further doctor blades may belong to the application device, in order to act in a smoothing manner on the layer of material.
[0068] The pivot arm 18 carrying the build platform 12 is connected by way of a pivot joint 20 to the vertically displaceable part of the lifting mechanism 14 . Also provided in the lifting mechanism 14 is a force transducer 29 , which measures the force exerted by the lifting mechanism 14 on the build platform 12 during the lowering and raising thereof and sends the measurement result to the control unit 12 . As described further below, said control unit is designed for the purpose of controlling the lifting mechanism 14 on the basis of a prescribed force profile, for example to limit the force exerted on the build platform 12 to a maximum value.
[0069] The way in which the device represented in FIGS. 1 and 2 functions can be summarized as follows. Under the control of the control unit, a prescribed amount of ceramic-filled light-polymerizable material 5 is discharged from the feed device 8 onto the vat bottom 6 . By controlling the drive 24 , the control unit 11 instigates a turning of the vat bottom 6 about the axis of rotation 22 , so that the discharged material passes the application device 26 , here a doctor blade, which smooths the light-polymerizable material to a prescribed layer thickness 32 , which is determined by the height setting of the application device 26 . Furthermore, by turning of the vat 4 , the material is brought into the region between the build platform 12 and the exposure unit 10 .
[0070] After stopping the turning movement of the vat 4 , here there then follows the lowering of the build platform 12 into the layer of light-polymerizable material 5 formed on the vat bottom 6 , which is explained below on the basis of FIGS. 3 to 5 . In the state shown in FIG. 3 , a layer of light-polymerizable material 5 with a prescribed thickness 32 is formed on the vat bottom, the build platform 12 still being located above the layer 5 in this state. Attached to the underside of the build platform 12 is a film 13 , which will be discussed further below. From the state represented in FIG. 3 , a lowering of the build platform 12 then takes place by the lifting mechanism 14 under the control of the control unit 11 , so that the build platform 12 with the film 13 on the underside is immersed into the layer of light-polymerizable material 5 and, as it is lowered further, displaces said layer partially out of the intermediate space between the film 13 and the upper surface of the vat bottom 6 . Under the control of the control unit 11 , the build platform 12 is lowered by the lifting mechanism 14 to the vat bottom in such a way that a layer with a precisely prescribed layer thickness 21 is defined between the build platform and the vat bottom. As a result, the layer thickness 21 of the material to be polymerized can be precisely controlled.
[0071] During the immersion of the build platform 12 into the light-polymerizable material 5 and the further lowering into the position shown in FIG. 4 , great forces could occur, particularly when material of relatively high viscosity is displaced, if the lowering of the build platform were to take place at the prescribed rate. In order to prevent the layers of material that build up during the lowering of the build platform 12 into the light-polymerizable material 5 from being exposed to great forces, in the lifting mechanism there is the aforementioned force transducer 29 , which measures the force exerted on the build platform 12 and sends the measurement signal to the control unit 11 . This control unit is only prepared for controlling the lifting mechanism in such a way that the force recorded by the force transducer 29 follows prescribed criteria, in particular that the force exerted does not exceed a prescribed maximum force. As a result, on the one hand the lowering of the build platform 12 into the light-polymerizable material 5 and the raising of the build platform out of said material can be carried out in a controlled manner such that the forces exerted on the build platform, and consequently also on the layers already formed, are limited and, as a result, detrimental effects are avoided during the buildup of the object, and on the other hand the lowering and raising of the build platform 12 can be carried out at the maximum possible rate at which detrimental effects on the object to be built up are still just avoided, in order in this way to achieve an optimal process rate.
[0072] After the lowering of the build platform into the light-polymerizable material 5 , into the position shown in FIG. 4 , there then follows the first exposure step for the polymerization of the first layer 28 on the build platform 12 , the invention providing that the further exposure unit 16 is thereby also actuated (at the same time or with a time delay), in order to ensure reliable adhesive attachment of the first polymerization layer 28 to the build platform. During the exposure process, the vat 4 is kept stationary, i.e. the drive 24 remains switched off. After the exposure of one layer, the build platform 12 is raised by the lifting mechanism 14 . In this case, however, before the raising of the build platform 12 , a relative tipping movement between the build platform 12 and the vat bottom 6 is preferably carried out first. This slight tipping movement is intended to serve the purpose of detaching the last-polymerized layer of the object 27 from the vat bottom 6 with less mechanical stress. After this tipping movement and detachment of the layer last formed, the build platform is raised by a prescribed amount, as shown in FIG. 5 , so that the layer last formed lies above the light-polymerizable material 5 on the object 27 .
[0073] Subsequently, material is again discharged from the feed device 8 and the vat 4 is turned by a prescribed rotational angle by the drive 24 , the material that moves past the doctor blade again being brought to a uniform layer thickness. This series of steps, with the forming of successive layers of a prescribed form of contour, is continued until the succession of layers with respectively prescribed geometry provides the desired form of the ceramic green blank.
[0074] The wiper 30 , provided behind the exposure unit and above the vat bottom 6 , may have various functions. For example, when it has been lowered fully onto the vat bottom 6 , it may serve the purpose of collecting the material from the vat bottom and carrying it away or returning it into the feed device 8 , which should take place at the end of a building process. During a building process, when it is raised slightly with respect to the vat bottom 6 , the wiper 30 serves the purpose of distributing the material again, in particular pushing the material back into the “holes” that have been created in the layer of material by the exposure process after raising of the build platform 12 .
[0075] After the completion of a building process, the build platform 12 with the exposure unit 16 fitted above it, can be pivoted upward as a whole by pivoting the pivot arm 18 about the joint 20 , as indicated by dashed lines in FIG. 1 . After that, there is better access to the vat 4 , for example to allow the latter to be cleaned or exchanged.
[0076] After the described buildup of the green blank from polymerized ceramic-filled material, said blank must be removed from the device and fed to a firing furnace, in which a decomposition of the polymerized binder (debinding) is brought about by the thermal treatment and a sintering of the ceramic material is carried out. To simplify the handling of the built-up body, the build platform is designed such that it can be easily detached from the carrier arm 18 . Then the build platform, with the built-up ceramic-filled object 27 adhesively attached to it, can be removed from its carrier 18 and placed in a firing furnace. In order to allow this preferred simple removal of the built-up dental restoration element of ceramic-filled polymer, the build platform must however be produced from a high-temperature-resistant material, for which zirconium oxide, aluminum oxide, sapphire glass or quartz glass may serve for example. Possible as an alternative to this is a self-adhesive, transparent film, which may be structured with nubs, channels, scores etc. on the side facing the photopolymer, for better adhesive attachment, and can be removed after the building process by simple detachment from the build platform or together with the build platform and passed together with the film into the firing furnace for debinding/sintering.
[0077] As compared with the device from FIGS. 1 and 2 with a rotatable vat, FIGS. 6 and 7 show an alternative embodiment, in which the vat 54 is designed such that it is movable linearly back and forth. In this embodiment, a vat 54 is mounted linearly movably on the housing 52 in a bearing 57 . Above the vat 54 , the feed device 58 is arranged in a height-adjustable manner. Offset from the feed device 54 with respect to the linear direction of movement, the build platform 62 is held above the vat 54 on a pivot arm 68 , which belongs to a lifting mechanism 64 . The pivot arm 68 is in turn provided with a pivot joint 70 , which allows the pivot arm 68 , after being raised in the vertical direction, to be turned by 180°, after which the build platform 62 with the object built up on it faces upward, and in this position can be easily handled.
[0078] Located below the build platform 62 and the vat bottom 56 is the projecting exposure unit 60 , in which a light source 65 with light-emitting diodes 73 is arranged. The light of the light source 65 is projected by way of a light modulator 67 and through the transparent vat bottom 56 onto the build platform 62 . Also present in the projecting exposure unit 60 is a reference sensor 51 , which is used in a calibration step for the purpose of recording the actual intensity distribution in the exposure area when the light modulator is controlled in such a way as to obviate any locational dependence or modulation over the exposure area. From the deviation of the intensity distribution actually recorded, a control profile (compensation mask) for the light modulator can then be calculated by inversion and provide an intensity that is actually uniform over the exposure area. A corresponding reference sensor 1 is also present in the case of the embodiment from FIGS. 1 and 2 .
[0079] Arranged in the direction of movement of the vat 54 (indicated by the double-headed arrow in FIGS. 6 and 7 ) are an application device 76 , which is held in a height-adjustable manner above the vat bottom 56 and here is in the form of a doctor blade, the lower edge of which lies at a suitable distance from the surface of the vat bottom, and a wiper 80 .
[0080] The way in which the device shown in FIGS. 6 and 7 functions corresponds to the method steps described above with reference to FIGS. 3 to 5 , apart from the difference of the linear movement back and forth of the vat 54 instead of the rotating movement of the vat 4 . Firstly, instigated by the control unit 61 , which actuates the drive 75 , the vat 54 is displaced from the position shown in FIG. 7 to the left into the position shown by dashed lines. In this case, light-polymerizable material is discharged by the feed device 58 onto the vat bottom 56 , the amount and variation over time of the discharge likewise being prescribed by the control unit 61 . After that, by reversing the drive 75 , the control unit 61 causes the vat 54 to be displaced back again. As this happens, the light-polymerizable material 55 discharged onto the vat bottom 56 first passes the wiper 80 and then the application device 76 , which ensure a uniform distribution and uniform layer thickness of the light-polymerizable material 55 , before it reaches the intermediate space between the build platform 62 and the projecting exposure unit 60 . After that, the drive 75 is stopped, whereupon the series of steps as described above in conjunction with FIGS. 3 to 5 is executed, the build platform 62 being immersed into the layer of light-polymerizable material 55 and a layer with prescribed thickness being defined between the build platform and the vat bottom by setting of the distance from the vat bottom. After that, the actuation of the projecting exposure unit 60 takes place to generate an exposure pattern with prescribed geometry, the further exposure unit 66 with its light-emitting diodes 69 also being actuated in this connection, at least during the generation of the first layer directly on the build platform 62 , in order to achieve complete polymerization and reliable adhesive attachment of the first layer to the build platform 62 .
[0081] After polymerization of the first layer with the desired geometry, the build platform 62 is raised again by actuating the lifting mechanism 64 , so that the polymerized layer formed is raised above the level of the light-polymerizable material 55 .
[0082] After that, the series of steps described is repeated, i.e. the vat 54 is again displaced to the left, light-polymerizable material is discharged from the feed device 58 and this material is distributed uniformly by the wiper 80 and the application device 76 when the vat 54 is pushed back to the right, after which, by switching off the drive 75 , the lifting mechanism 64 lowers the build platform again, so that the last-formed polymerized layer is immersed into the light-polymerizable material 55 and is brought to a prescribed distance above the vat bottom, in order to polymerize the layer of material that is then lying in the intermediate space in the next exposure step. The increment of the movement back and forth can of course be varied again, in order to avoid polymerization always being carried out over the same place on the vat bottom.
[0083] The lifting mechanism 64 is in turn provided with a force transducer 79 , the measured values of which are used by the control unit 61 in the way described above in connection with the first embodiment for limiting the force that is exerted on the build platform during the lowering and raising of the build platform.
[0084] Methods in which multiple different ceramic-filled photopolymerizable materials are used for building up the green blank may preferably also be used. This may take place, for example, by a plurality of vats being provided, each with an assigned reservoir with different materials. These vats may then be moved to the exposure unit and the build platform in the manner of a changeover carrier, in order to process different materials in a prescribed sequence. For this purpose, the multiple vats may, for example, be arranged in series one behind the other on a carrier, which is then linearly movable with respect to the exposure unit and the build platform, in order to provide a desired vat in each case. Alternatively, a plurality of rotatable vats, one of which is represented in FIGS. 1 and 2 , may be arranged on a circular ring of a larger plate, which for its part is in turn rotatable, in order in each case, by setting the rotational position of the plate, to bring a desired vat into the position between the exposure unit and the build platform in which the polymerization step of the respective layer is then carried out.
[0085] A special embodiment of a device with which various light-polymerizable materials can be used for building up an object is shown in FIG. 8 in a schematic plan view from above. Here there are four vats 104 on a turntable, arranged in the form of a circular ring. The arrangement of the feed device 108 , the further exposure unit 116 on a lifting mechanism 114 as well as the wiper 130 and the application device 126 lying in between is largely similar to the arrangement of the device from FIGS. 6 and 7 , with the exception of the fact that the components are not arranged along a linear path and the vat is not linearly movable, but instead the components are arranged along a segment of a circular ring and the vat correspondingly has the form of a segment of a circular ring. Between successive exposure steps in the same vat 104 , the vat is moved back and forth by an angle of approximately less than 90°, so that in turn a movement back and forth is obtained between the feed device 118 and the build platform located under the further exposure unit 108 .
[0086] If at a specific point in time one of the materials from one of the three other vats 104 is to be used, the turntable is turned by an angle corresponding to 90°, 180° or 270°, in order to bring one of the following vats to the device under consideration for building up the object.
[0087] As indicated at the bottom in FIG. 8 , a further device for building up objects, which can operate in parallel with the device shown at the top, may be provided on the turntable in the region of another segment of a circular ring.
[0088] Although the present invention has been described in connection with preferred embodiments thereof, it will be appreciated by those skilled in the art that additions, deletions, modifications, and substitutions not specifically described may be made without department from the spirit and scope of the invention as defined in the appended claims. | A method and a device for processing a light-polymerizable material ( 5, 55 ) for building up an object ( 27 ) in layers, using a lithography based generative manufacture having a construction platform ( 12 ) for building up the object ( 27 ), a projecting exposure unit ( 10, 60 ) that can be controlled for locally selected exposing of a surface on the construction platform ( 12, 62 ) to an intensity pattern having a prescribed shape, and a control unit ( 11, 61 ) prepared for polymerizing overlapping layers ( 28 ) on the construction platform ( 12, 62 ) in successive exposure steps, each having a prescribed geometry, by controlling the projecting exposure unit ( 10, 60 ), in order to thus successively build up the object ( 27 ) in the desired shape, said shape resulting from the sequence of layer geometries. The invention is characterized in that a further exposure unit ( 16, 66 ) for exposing the surface of the construction platform ( 12, 62 ) is provided on the side opposite the projecting exposure unit ( 10, 60 ), and that the construction platform ( 12, 62 ) is designed to be at least partially transparent to light, and that the control unit ( 11, 61 ) is designed for controlling the further exposure unit ( 16, 66 ) at least while building up the first layer ( 28 ), said layer adhering to the construction platform ( 12, 62 ), for exposing in the prescribed geometry. | 1 |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to manually operated vibratory plate compactors and, more particularly, to an improved seal arrangement for the piston of a shift rod used to control movement of the compactor. The seal arrangement is readily accessible and the seals may be individually replaced or a new piston and seal subassembly substituted for the subassembly needing repair or replacement.
[0002] Manually operated vibratory plate compactors are well known and commonly used for compacting soil in back-fill, sub-grade and other construction activity compaction applications. In one typical vibratory plate compactor, pairs of parallel shafts carrying eccentric weights are rotated by driving one shaft and transmitting the rotation to the other with a gear arrangement. The eccentric weight arrangement and a drive engine are mounted on a substantially flat compaction plate. An operator's handle with controls is also attached to the plate frame. The operator controls include an actuator which can be used to adjust the rotational position of the eccentric weights on the shafts. Such adjustment alters the phase and vector of the forces generated by the eccentric weights such that the plate compactor may be made to move in a forward direction, a reverse direction, or to remain horizontally stationary, all while imposing vertical compacting forces on the surface beneath the plate.
[0003] One common means for adjusting the phase of the eccentric weights is to use a hydraulic actuator including a piston mounted coaxially in or with respect to a bore in the driven input shaft of the apparatus, the piston connected by a shift rod to a carrier head carrying a cross pin that engages a helical groove on the ID of the main input shaft bore. Movement of the shift rod assembly axially in the input shaft bore provides the rotation of the shaft and attached eccentric weights to adjust the phase. Such apparatus is shown, for example, in U.S. Pat. Nos. 4,356,736; 5,010,778; and 5,818,135.
[0004] In all of the prior art apparatus of the foregoing general type, the shafts carrying the eccentric weights and drive gears are encased in a housing partially filled with a liquid lubricating oil. The piston on the shift rod is typically connected to a supply of hydraulic fluid which is applied to the free end of the piston, operating either in a bore in the input shaft or in a cylinder housing attached coaxially to the shaft, to move the carrier and cross pin on the opposite end of the shift rod axially to rotate the input shaft for phase adjustment, thereby adjusting the speed and direction of forward and reverse movement of the compactor.
[0005] It is known in the prior art to provide the shift rod piston with a seal to prevent hydraulic fluid in the piston cylinder from bypassing the piston and escaping into the main housing. The seal is typically a uni-directional type such as a lip seal or cup seal that expands with increasing hydraulic pressure to inhibit leakage. When actuating hydraulic pressure on the piston is reduced or relieved, the eccentric weights shift in an opposite rotational direction under the influence of rotation of the main input or drive shaft to initially reduce the speed of movement in one direction (typically reverse) to a neutral or horizontally stopped position and then to increase speed in the opposite (forward) direction. Thus, the shift rod piston needs only to be single-acting and, therefore, it has been assumed in the prior art that a unidirectional piston seal to prevent leakage of pressurized hydraulic fluid was adequate.
[0006] It has been found, however, that under certain circumstances of operation, lubricating oil in the main housing can become pressurized and escape past the uni-directional seal on the piston where it becomes trapped in the cylinder housing. The lubricating oil in the housing may become pressurized as a result of high temperatures generated during operation. Also, the rapidly rotating shafts in the housing tend to stir up the lubricating oil causing it to atomize and, under pressure, seep past the seal. The accumulation of lubricating oil in the chamber intended to receive pressurized hydraulic fluid interferes with proper movement of the piston and, as a result, eventually interferes with operating movement of the compactor.
[0007] The high operating temperatures experienced by these kinds of vibratory plate compactors also create a hostile environment for any type of seal. Thus, the prior art piston seal must be periodically replaced and great care must be taken to avoid contamination of the interior of the housing during seal replacement. In addition, the construction of prior art apparatus has made seal replacement tedious and time consuming, sometimes requiring the removal of the main housing cover and partial disassembly of the eccentric weights from the drive shaft to access the shift rod and piston so the seal may be replaced. Opening the cover plate for the main housing also exposes the entire interior of the mechanism to potential contamination.
SUMMARY OF THE INVENTION
[0008] In accordance with the present invention, the shift rod piston is provided with a double seal to protect against leakage of pressurized lubricating oil from the interior of the housing in cooperation with a prior art piston seal to prevent the ingress of hydraulic fluid from the cylinder housing. An improved demountable cylinder housing makes access to the shift rod and piston much easier and the piston is demountably attached to the shift rod so that the entire subassembly of a piston head and new seals may be easily substituted for the old and worn subassembly.
[0009] In accordance with the preferred embodiment of the invention, the demountable connection of the piston to the shift rod comprises a threaded connection. The annular piston seals preferably comprise cup seals oriented to face in opposite axial directions. The cylinder housing preferably includes an integral peripheral outer flange that is adapted to engage the outer wall of the main housing. A mounting plate comprising an annular clamping plate holds the cylinder housing flange in engagement with the outer wall and is held in place with a plurality of threaded fasteners. The bore in the cylinder housing preferably comprises a through bore to facilitate machining. A demountable cover plate encloses the outer end of the through bore.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] [0010]FIG. 1 is a vertical sectional view taken laterally through a vibratory plate compactor incorporating the apparatus of the subject invention.
[0011] [0011]FIG. 2 is a horizontal section taken on line 2 - 2 of FIG. 1.
[0012] [0012]FIG. 3 is an enlarged sectional detail taken on line 3 - 3 of FIG. 2.
[0013] [0013]FIG. 4 is a side elevation of the apparatus shown in FIG. 2
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] A vibratory plate compactor 10 includes a horizontal bottom compaction plate 11 through which vertical compactive forces, generated by an attached rotary eccentric weight mechanism 12 are transmitted to the soil or other base material underlying the plate 11 . The compaction plate 11 , as best seen in FIG. 4, is part of a casting and includes upwardly tapered front and rear portions 13 to facilitate movement of the compactor in forward and reverse directions. The casting also includes front and rear frame members 14 that are formed integrally with the compaction plate 11 and to which are attached an operator's handle (not shown) and a drive engine with supporting brackets (also not shown). Between the front and rear frame members and also forming part of the casting is a generally rectangular main housing 15 in which the rotary eccentric weight mechanism 12 is enclosed. The housing is enclosed from above with a removable top plate 16 .
[0015] The rotary eccentric weight mechanism 12 includes a main rotary input shaft 17 journaled at its opposite ends in the side walls 20 of the main housing 15 with bearings 18 . A pair of main eccentric weights 21 are secured to the main input shaft 17 for rotation therewith. A drive gear 22 is also mounted on the main input shaft 17 between the eccentric weights 21 and rotates with the shaft and weights. One end of the input shaft 17 extends through the side wall 20 and has mounted thereon a drive pulley 23 for operative attachment to the drive engine with a V-belt (not shown). A driven shaft 24 is also journaled in the side walls 20 of the main housing 15 with bearings 25 . The driven shaft 24 has a driven gear 26 centrally mounted thereon and in engagement with the drive gear 22 on the main input shaft 17 . A pair of eccentric weights 27 are also mounted on driven shaft 24 for rotation therewith. Driving rotation of the main input shaft 17 transmits a counter-rotation to the driven shaft 24 via the gears 22 and 26 .
[0016] As indicated, the eccentric weights 21 are fixed to the main input shaft 17 and the eccentric weights 27 are similarly fixed to the driven shaft 24 so that they rotate, respectively, therewith. In a manner generally known in the art, the relative rotational positions of the eccentric weights 21 and 27 on their respective shafts 17 and 24 can be varied to change the phase relationship of the forces generated during operation. The relative rotational positions of the eccentric weights are adjusted by limited rotation of the main input shaft 17 which transmits a similar but opposite limited counter-rotation to the driven shaft 24 . This phase adjustment permits the compactor 10 to be driven in a forward direction at a variably adjustable speed, stopped to operate without horizontal movement, or driven at a variable adjustable speed in a reverse direction.
[0017] The adjustment mechanism 28 for effecting the change in eccentric weight phase is operatively connected to the main input shaft 17 . This adjustment mechanism includes several features which constitute improvements over the prior art, as will be described hereinafter. The main input shaft 17 is provided with a long blind bore 30 and, near the interior end thereof, the shaft wall is provided with a pair of diametrically opposite matched helical slots 31 . A cylindrical carrier 32 is slidably mounted in the bore 30 and is journaled with bearings 33 on one end of a shift rod 34 positioned axially in the bore 30 . On the opposite end of the shift rod 34 is mounted a piston 35 by a threaded connection 36 comprising a threaded OD on the end of the rod 34 and a threaded ID on a counter-bore in the piston 35 . The piston 35 is carried in a cylinder housing 37 which is provided with a through bore 38 within which the piston may be reciprocated axially. The cylinder housing 37 has a lead end provided with a extended sleeve 40 that extends with the clearance into the bore 30 of the input shaft 17 and provides an extended bore for the piston 35 . Pressurized hydraulic fluid is supplied via a fitting 41 to the cylinder bore 38 and acts against the free face of the piston 35 to move the piston, shift rod 34 and carrier 35 in the direction away from the fitting. A cross pin 43 is mounted in a cross bore 42 in the carrier 32 as best shown in FIG. 3. The opposite ends of the cross pin 43 extend into the helical slots 31 with a small clearance so that the cross pin may slide in the helical slots. Axial movement of the adjustment mechanism 28 along the path of the helical slots causes limited rotational movement of the input shaft 17 and the drive gear 22 mounted thereon. This limited rotational movement is transferred to the driven gear 26 mounted on the driven shaft 24 . The result is relative counter rotational movement of the respective eccentric weights 21 and 27 , resulting in the phase adjustment described above and the resultant change in horizontal movement of the compactor 10 . As indicated, the carrier 32 is journaled on the end of the shift rod 34 such that the carrier and the cross pin 43 rotate with the main input shaft 17 . Thus, axial movement of the carrier under the influence of hydraulic pressure in the cylinder housing 37 may be utilized to move the cross pin in the helical slots 31 to provide on-the-fly phase adjustment while the shafts 17 and 24 are rotationally driven.
[0018] Referring again to FIG. 1 and also to FIG. 4, the bottom of the main housing 15 provides a reservoir 44 for a lubricating oil for the various bearings and gears mounted in the housing. Typically, the reservoir 44 is filled to a fairly low level sufficient to permit the teeth of the gears 22 and 26 to pick up lubricating oil during rotation and have it spread throughout the housing by the other rotating parts, such as the bearings and eccentric weights, into which it comes in contact. The rapidly rotating parts tend to break the oil into minute droplets and to even create an oil mist which penetrates and lubricates the bearings and other moving parts. The generation of high operating temperatures inside the housing 15 results in an increase in internal pressure. Although pressure relief may be provided, it has been found that, in prior art devices, a piston 35 having only a single seal, will permit the passage of lubricating oil past the piston and into the cylinder housing 37 . A very small volume of leakage into the cylinder housing where it mixes with pressurized hydraulic fluid, has been found sufficient to interfere with operation of the adjustment mechanism 28 . As a result, proper control of the compactor is lost. Normal wear of the single piston seal with use and seal degradation at high operating temperatures both add to worsen the leakage problem.
[0019] Referring also to FIG. 3, in addition to the single hydraulic pressure seal 45 typical of prior art constructions, the piston 35 of the present invention also includes an oppositely acting lubricant seal 46 at the opposite axial end of the piston. The piston also includes a guide ring 49 between the two seals 45 and 46 , the guide ring being typical of prior art constructions. The lubricant seal 45 for the piston 35 of the improved phase adjustment mechanism is preferably a cup seal and may be of the construction and material identical to the oppositely facing hydraulic pressure seal 45 . Each of the seals is, of course, oriented to enhance sealing engagement in response to increased pressure. A typical seal material for this application would be a polyether-based urethane, but other synthetic rubber materials could also be used. Instead of two separate seals 45 and 46 , a single double-acting seal could be used.
[0020] Another problem with certain prior art compactor constructions was that, when seal replacement was necessary, access to the piston was difficult and time consuming, and furthermore, often required access to the interior of the main housing and removal of parts of the eccentric weight mechanism. All of this contributed to the potential for contamination. In accordance with the present invention, the cylinder housing 37 is made to be easily removable from the main housing 15 , making access to the piston for repair or replacement of the seals possible without direct access to the interior of the main housing 15 . The side wall 20 of the main housing 15 is provided on both sides with large circular openings 29 , each of which is closed by an end cover 19 that also provides a housing for the main bearings 18 . Each end cover 19 is secured to its respective side wall 20 with mounting bolts 53 (see FIG. 4). The cylinder housing 37 includes a shoulder 39 the OD of which provides a pilot surface for centering the cylinder housing in a central opening 54 in one of the end covers 19 . The cylinder housing 37 also includes a peripheral flange 47 that engages the end cover 19 when the sleeve 40 is inserted into the bore 30 in the input shaft and the pilot shoulder 39 is received in the central opening 54 . The housing 37 is held in place with a clamping plate 48 which, in turn, is demountably attached to the end cover 19 with four machine screws 50 . When access to the piston 35 and seals 45 , 46 is required, the clamping plate 48 and cylinder housing 37 are removed to expose the piston. If necessary, the piston may be pulled axially out of the housing so the seals may be removed and replaced. Preferably, however, the entire piston is removed by grasping the shift rod 34 (e.g. with a pliers) and unthreading the piston at the threaded connection 36 . Then the entire piston including new seals 45 and 46 and guide ring 49 may be replaced as a unitary subassembly quickly and with a minimum of effort.
[0021] It will be noted in the drawings, such as the detail of FIG. 3, that the throughbore 38 in the cylinder housing is closed with a cover plate 51 . The throughbore 38 itself is utilized simply to make machining more accurate and easy to accomplish (as compared, for example, to blind bores provided in certain prior art constructions). The cover plate 51 is attached with a number of machine screws 52 , but the plate does not have to be removed for any repair or maintenance activities. With the improved construction and easy access provided by the subject invention, the piston and seal subassembly may be replaced in about 20 minutes. In the prior art construction without an easy access cylinder housing and requiring access to the piston by removal of the main top plate 16 , replacement of the piston seals would take three to four hours. | An easily accessible phase adjustment mechanism for a vibratory plate compactor includes an improved seal arrangement to protect against leakage of internal lubricating oil into the hydraulic cylinder providing fluid pressure to the adjustment mechanism. An easily demountable cylinder housing provides ready access to the piston and seal assembly which can then be threadably detached and replaced in its entirety. | 8 |
[0001] The invention relates particularly, but not exclusively, to the provision of a method and apparatus for the improvement of plasma processing in the application of coatings to substrates and to the improved control and efficiency in the application of specific coatings.
[0002] Plasma modification is widely employed to modify the surface properties of bulk materials and the term is used to describe the use of gases and/or monomers or polymerisation to bring about the modification. By introducing inorganic or organic gases/monomers (including those that are not polymerisable by conventional methods) into the electrical discharge, specific functional groups can be applied onto the substrate. In the case of polymeric substrates, scission of the polymer backbone in the surface region caused by incident ions, photons, and reactive neutrals from the plasma, can often lead to the formation of poorly adherent low molecular weight species. As a consequence, the surface properties can become unstable and disappear over a period of time, or be lost during immersion in a solvent.
[0003] The practical and commercial problems caused by this disadvantage are significant as water-absorbing resins are widely used commercially such as in sanitary goods, hygienic goods, wiping cloths, water retaining agents, dehydrating agents, sludge coagulants, disposable towels, and release control agents for various chemicals. Such resins are available in a variety of chemical forms, including substituted and unsubstituted natural and synthetic polymers, such as hydrolysis products of starch acrylonitrile graft polymers, carboxymethyl cellulose, crosslinked polyacrylates, sulphonated polystyrenes, hydrolysed polyacrylomides, polyvinyl alcohols, polyethylene oxides, and many others. These water-absorbing resins are often termed “super absorbent polymers” or SAPS, and typically comprise crosslinked hydrophilic polymers. SAPs are normally capable of absorbing and retaining amounts of aqueous fluids equivalent to many times their own weight, even under moderate pressure. The dramatic welling and absorbent properties of SAPS are attributed to (a) electrostatic repulsion between the charges along the polymer chains, and (b) osmotic pressure of the counter ions. The ability to absorb aqueous fluids under a confining pressure is an important requirement for a SAP used in a hygienic article, like a diaper.
FIELD OF THE INVENTION
[0004] The invention relates particularly, but not exclusively, to the provision of a method and apparatus for the improvement of plasma processing in the application of coatings to substrates and to the improved control and efficiency in the application of specific coatings.
BACKGROUND OF THE INVENTION
[0005] Plasma modification is widely employed to modify the surface properties of bulk materials and the term is used to describe the use of gases and/or monomers or polymerisation to bring about the modification. By introducing inorganic or organic gases/monomers (including those that are not polymerisable by conventional methods) into the electrical discharge, specific functional groups can be applied onto the substrate. In the case of polymeric substrates, scission of the polymer backbone in the surface region caused by incident ions, photons, and reactive neutrals from the plasma, can often lead to the formation of poorly adherent low molecular weight species. As a consequence, the surface properties can become unstable and disappear over a period of time, or be lost during immersion in a solvent.
[0006] The practical and commercial problems caused by this disadvantage are significant as water-absorbing resins are widely used commercially such as in sanitary goods, hygienic goods, wiping cloths, water retaining agents, dehydrating agents, sludge coagulants, disposable towels, and release control agents for various chemicals. Such resins are available in a variety of chemical forms, including substituted and unsubstituted natural and synthetic polymers, such as hydrolysis products of starch acrylonitrile graft polymers, carboxymethyl cellulose, crosslinked polyacrylates, sulphonated polystyrenes, hydrolysed polyacrylomides, polyvinyl alcohols, polyethylene oxides, and many others. These water-absorbing resins are often termed “super absorbent polymers” or SAPS, and typically comprise crosslinked hydrophilic polymers. SAPs are normally capable of absorbing and retaining amounts of aqueous fluids equivalent to many times their own weight, even under moderate pressure. The dramatic swelling and absorbent properties of SAPS are attributed to (a) electrostatic repulsion between the charges along the polymer chains, and (b) osmotic pressure of the counter ions. The ability to absorb aqueous fluids under a confining pressure is an important requirement for a SAP used in a hygienic article, like a diaper.
[0007] Conventionally the absorption properties of SAPs are drastically reduced in solutions containing electrolytes, such as saline, urine and blood. The polymers do not function as effective SAPs in the presence of such physiological fluids. The absorption capacity of SAPS for body fluids, like urine and menses, therefore, is dramatically lower than for deionised water because such fluids contain electrolytes. This dramatic decrease in absorption is termed “salt poisoning”.
[0008] The salt poisoning effect can be explained as follows. Water-absorption and water retention characteristics of SAPs are attributed to the presence of ionisable functional groups in the polymer structure. The ionisable groups typically are carbonyl groups, a high proportion of which are in the salt form when the polymer is dry, and which undergo dissociation and solvation upon contact with water. In the dissociated state, the polymer chains contain a plurality of functional groups having the same electric charge and, thus, repel one another. This electronic repulsion leads to expansion of the polymer structure, which in turn, permits further absorption of water molecules. Polymer expansion, however, is limited by the crosslinks in the polymer structure, which are present in a sufficient number to prevent solubilisation of the polymer. A significant concentration of electrolytes can interfere with the dissociation process of the ionised functional groups, and lead to the “salt poisoning” effect. Dissolved ions such as sodium and chloride ions, therefore, have two effects on SAP gels. The ions screen the polymer charges and eliminate the osmotic imbalance due to the presence of counter ions inside and outside of the gel. The dissolved ions, therefore, effectively convert an ionic gel into a non-ionic gel, and swelling properties are lost.
[0009] Numerous investigations are known to have attempted to counteract the salt poisoning effect and therefore improve the absorption performance of SAPs with respect to electrolyte-containing liquids, such as urine and menses. The introduction of both cationic and anionic exchange materials has been and continues to be investigated to alleviate the salt poisoning effect by reducing the salt content in the absorbed liquid. The ion exchanger has no direct effect on the performance of the superabsorbent materials but rather attempts to “condition” the liquid. However, in practise it may not be possible to reduce the salt content sufficiently to have the desired effect on the overall absorption capacity of the combination. In addition, besides being expensive, the ion exchanger has no absorbing effect itself and thus acts as a diluent to the superabsorbent material. It is possible to make anionic superabsorbents with suitable cationic functional groups including quaternary ammonium groups or primary, secondary or tertiary amines that should be present in base form. In fact the most commonly used SAP for absorbing electrolyte-containing liquids, like urine, is neutralised polyacrylic acid. Neutralised polyacrylic acid, however, is susceptible to salt poisoning.
SUMMARY OF THE INVENTION
[0010] The aim of the present invention is to provide an improved superabsorbent material which allows improved absorbance of liquids in general, and in particular, liquids containing electrolytes.
[0011] In a first aspect of the invention there is provided a method of applying a conditioning effect to a material substrate, said method including the step of performing a plasma modification and/or plasma deposition treatment on the substrate, said conditioning effect comprising exposing the substrate to any, or any combination of, at least two treatment steps: (i) crosslinking of either or both the exterior and internal surfaces of the material; and/or (ii) plasma modification or plasma deposition of/onto the cross-linked material.
[0012] Typically the steps (i) and (ii) are both performed and in sequence onto a superabsorbent material, hereinafter referred to in a non-limiting manner as the substrate.
[0013] In one embodiment the precursor gas used in the generation of the plasma is, by way of example only, a noble, inert or nitrogenous gas.
[0014] In one embodiment a coating material is modified and in one embodiment is a hydrophilic layer wherein the plasma treatment in the second step acts to oxidise or nitrogenate the same. The precursor gas/liquid used during the second plasma treatment step can be oxygen or nitrogen containing chemical compounds. Any suitable oxidation method can be used, such as ozonolysis
[0015] Preferably, when the coating applied is either a hydrophobic/oleophobic layer, the precursor gas/liquid used for the plasma treatment in step (ii) contains fluoride.
[0016] Suitable types of plasma and remote plasma can be used and reference to the use of plasma can include the use of any or any combination of pulsed and/or continuous wave plasma and include non-equilibrium plasmas such as those generated by radio frequency (R-F), microwaves and/or direct current. The plasma can be operated at low pressures, atmospheric or subatmospheric pressures to suit particular purposes.
[0017] In operation, the plasma power applied during the first step can be in the range 0.01 watt to 500 Watts.
[0018] In operation the plasma power applied during the second step can be in the range 0.01 watt to 500 Watts.
[0019] In one embodiment the plasma power applied during either or both of the first and second steps is pulsed. In addition, or alternatively, the precursor gas/liquid introduced during either or both the first and second steps is pulsed.
[0020] Typically the material which is modified is a substrate which is defined as any article which is capable of supporting a coating applied thereto, so it will be appreciated that the same can be rigid or flexible, and can be any of a porous or non-porous substrate such as a film, powder or 3-dimensional article.
[0021] In one embodiment, when the substrate is a porous article, the substrate has an exterior surface, a bulk matrix and pores extending from the exterior surface into the bulk matrix, wherein the bulk matrix is, at least in part, polymeric or oligomeric, and the exterior and interstitial surfaces, at least in part, are polymeric or oligomeric.
[0022] In one embodiment the porous matrix is a polyolefin. The porous matrix can have a void volume ranging from 0.01% to 99%, but most preferably between 1% and 99%.
[0023] In a further embodiment where the substrate is a non-porous article the surface is composed of fabric, metal, glass, ceramic, paper or polymer.
[0024] In one embodiment, in step (i) the effect of said step can be controlled to be applied only to a limited depth or throughout the material below the external surface.
[0025] In one embodiment, in step (ii) the effect of said step can be controlled to be applied to a limited depth below or throughout the material below the external surface.
[0026] In one embodiment the plasma used in either or both steps (i) and (ii) is selectively applied to localised areas across the substrate surface and/or below the substrate surface.
[0027] In one embodiment of the invention there is provided an absorbent, hydrophobic polymer, such as polyacrylic acid which is cross-linked by a noble gas plasma, improving its ability to retain water and rendering it super absorbent. Preferably a subsequent nitrogenating plasma then renders said cross-linked polymer compatible with amine functionalities and thus the overall effect of the two step treatment is the formation of a super-absorbent polymer with the ability to retain large quantities of amine containing aqueous solutions.
[0028] In one embodiment, products modified in accordance with the invention have application in, for example, the formation of an article for absorbing bodily fluids such as, for example, a nappy (aka diaper), wound dressings, burns treatment, printing techniques, bio integrated circuits, and generally any product where absorbance of liquid is a problematic issue.
[0029] Typically, any suitable cross linking method can be used such as e-beam lithography.
[0030] The effect of the first step of the method is to improve the thermal stability of the polymer, which in turn means that it can be plasma treated in the second step at higher temperatures. Thus it is preferred that both steps are performed as, without the first step, the second step can cause the polymer to deteriorate.
[0031] The invention is also applicable to copolymer and blend coatings thereby having the same advantageous effect.
[0032] In addition to improving the characteristic of the substrate surface, the application of material to the substrate surface such as, for example, by plasma deposition, is improved both in the application of the coating and the adhesion of the coating to the substrate surface as the two-step process also leads to an improvement in surface adhesion.
[0033] Specific embodiments of the invention are now described with reference to the accompanying diagrams, wherein:—
[0034] Structures 1 - 3 relate to Dimethyl Sulphate, sulphur monoxide and sulphite respectively.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] FIGS. 1A and B illustrate the water contact angle of polypropylene film exposed to varying levels of argon plasma crosslinking followed by plasma polymerisation of dimethyl sulphate; (a) before washing; and (b) after washing with propan-2-ol;
[0036] FIGS. 2 a and b illustrate the water absorption profiles for plasma polymerisation of dimethyl sulphate onto a porous nonwoven polypropylene stack as a function of power: (a) before washing; and (b) after washing with propan-2-ol;
[0037] FIGS. 3 a and b illustrate the water absorption capacity of the outermost layer of porous non-woven polypropylene stack as a function of argon plasma and dimethyl sulphate plasma power level settings: (a) before washing; and (b) after washing with propan-2-ol;
[0038] FIGS. 4 a and b illustrates the XPS spectra following dimethyl sulphate plasma polymerisation onto non-porous polypropylene film as a function of input power: (a) S(2p); and (b) C(1s);
[0039] FIG. 5 illustrates the XPS S/C ratios at various power level settings for dimethyl sulphate plasma polymerisation (in the absence of argon plasma pre-treatment);
[0040] FIGS. 6 a and b illustrate the XPS S/C ratios of dimethyl sulphate plasma polymers deposited onto a porous non-woven polypropylene stack at 3 W and 10 W before and after propan-2-of washing: (a) no pre-treatment; and (b) 50 W Ar plasma pretreatment;
[0041] FIG. 7 illustrates the Substrate subtracted ATR FTIR spectra of dimethyl sulphate plasma polymer deposited onto non-porous polypropylene film as a function of power level;
[0042] FIGS. 8 a - e illustrate the optical microscopy images of porous non-woven polypropylene fibres; (a) untreated; (b) dimethyl sulphate (3 NV); (c) dimethyl sulphate (10 W); (d) argon (50 W) and dimethyl sulphate (3W); and (e) argon (50 W) and dimethyl sulphate (10 W);
[0043] FIG. 9 illustrates absorption under load of test liquids by treated polyacrylic acid SAPs modified at various argon plasma power levels;
[0044] FIG. 10 illustrates absorption under load of test liquids by treated polyacrylic acid SAPS modified at various nitrogen plasma power levels;
[0045] FIG. 11 illustrates absorption under load of test liquids by treated polyacrylic acid SAPS modified by argon plasma at 20 W and various nitrogen power levels;
[0046] FIG. 12 illustrates substrate subtracted ATR FTIR spectra of polyacrylic acid modified with nitrogen plasma at (a) untreated polyacrylic acid; (b) 5 W; (c) 10 W, and (d) 20 W;
[0047] FIGS. 13 a and b illustrate water contact angles of polypropylene films exposed to varying levels of argon plasma crosslinking followed by air plasma treatment;
[0048] FIG. 14 illustrates water absorption profiles for air plasma treated porous non-woven polypropylene stack at various powers;
[0049] FIGS. 15 a and b illustrate top layer water absorption of nonwoven polypropylene stack;
[0050] FIG. 16 illustrates XPS O/C rates of polypropylene films as a function of air plasma power input; and
[0051] FIG. 17 a - f illustrate optical micrographs of non-woven porous polypropylene.
DETAILED DESCRIPTION OF THE INVENTION
[0052] In this first specific, illustrative embodiment, relatively small (6 cm×2 cm) strips of non-porous polypropylene film (capacitor grade, ICI, 0.5 μm thickness) and also porous non-woven polypropylene film (Corovin GmbH, MD300A, 125 μm thickness) were rinsed in non-polar (cyclohexane) followed by polar (propan-2-ol) solvents, and then dried in air. In the case of the porous substrate, 8 sheet stacks were used in order to evaluate the depth of plasma penetration.
[0053] Plasma crosslinking and deposition treatments were carried out in a cylindrical glass reactor pumped by a rotary pump via a liquid nitrogen cold trap (base pressure=1×10-2 mbar, leak rate=9.9×10-9 mol s-1). A copper coil wrapped around the reactor was connected to a 13.56 MHz radio frequency power supply via an LC matching network. Prior to each experiment the chamber was cleaned using an air plasma operating at 50 W and 0.2 mbar. At this stage the polymer substrate was placed into the centre of the reactor. The noble gas pre-treatment step entailed introducing Argon (99% purity, Air Products) at a pressure of 0.2 mbar followed by plasma ignition for 5 min. Immediately afterwards dimethyl sulphate precursor (Aldrich, 99% purity, further purified using several freeze-pump-thaw cycles) was introduced via a fine control needle valve at a pressure of 0.1 mbar and 4.0×10-8 mol s-1 flow rate followed by re-ignition of the electrical discharge for 5 min.
[0054] Film thickness measurements were carried out using an nkd-6000 spectrophotometer (Aquila Instruments Ltd). Transmission-reflectance curves (350-1000 nm wavelength range) were fitted to a Cauchy model for dielectric materials using a modified Levenburg-Marquardt method.
[0055] For the non-porous polypropylene film substrates, sessile drop water contact angle measurements were carried out using a video capture apparatus (AST Products Inc., Model VCA 2500). Each contact angle value was acquired 10 s after dispensing a 2 μl drop of high purity water onto the surface. In the case of the porous non-woven polypropylene film substrate, water absorption measurements were adopted as a means for following changes in wettability. This entailed immersion of individual plasma treated sheets into 1 ml of aqueous dye solution (0.625 wt % solution of blue dye Coumarin 47 , Parker Pen Company). Any remaining excess liquid was then combined with water to make a 1 ml aliquot and analysed by UV-VIS absorption spectroscopy at 200 nm (this wavelength corresponds to dye absorption) using a UNICAM UV4 spectrophotometer. Reference was made to a set of calibration solutions. The possibility of there also being low molecular weight species present on the plasma treated surfaces was investigated by rinsing the samples in propan-2-ol, and then re-examining their surface wettability.
[0056] A VG Escalab spectrometer equipped with an unmonochromatised Mg Ka X-ray source (1253.6 eV) and a concentric hemispherical analyser was used for X-ray photoelectron spectroscopy (XPS) analysis of the modified surfaces. Elemental compositions were calculated using sensitivity factors derived from chemical standards, O(1s): C(1s): S( 2 p ) equals 0.45:1.00:0.60.
[0057] Substrate subtracted attenuated total reflectance (ATR) infrared spectra of plasma polymer films deposited onto polypropylene film were acquired using a diamond ATR accessory (Graseby Specac Golden Gate) fitted to a Perkin Elmer Spectrum One FTIR spectrometer. Spectra were acquired at a resolution of 4 cm −1 over 500-4000 cm −1 wavelength range using a liquid nitrogen cooled MCT detector.
[0058] In analysis of the results a water contact angle value of 95°±3 was measured for the untreated non-porous polypropylene film surface. Plasma polymerisation of dimethyl sulphate directly onto this substrate produced an improvement in hydrophilicity consistent with previous studies, as shown in FIG. 1A . A decrease in contact angle value was observed with rising power, eventually reaching a limiting value of around 6° around 8 W. Higher power settings produced no further improvement in surface wettability. Washing these plasma modified surfaces with propan-2-of indicated a divergence in performance, as shown in FIG. 1B . Retention of hydrophilicity was greatest at lower power level settings, whereas at higher powers, the water contact angle value became more reminiscent of the original untreated polypropylene substrate (i.e. the deposited plasma polymer layer was being dislodged from the surface by solvent).
[0059] Argon plasma pre-treatment prior to plasma polymerisation of dimethyl sulphate produced two beneficial effects. Firstly, an improvement in surface wettability was noted, and in addition, the deposited dimethyl sulphate plasma polymer layer exhibited greater stability towards solvent removal, FIG. 1B . The most hydrophilic and stable surfaces were achieved by using a combination of high power levels for both argon plasma crosslinking and plasma polymerisation of dimethyl sulphate.
[0060] Water absorption measurements for dimethyl sulphate plasma polymer layers deposited onto porous non-woven polypropylene films displayed several important attributes. Firstly, the degree of hydrophilicity was dependent upon depth, FIG. 2 a . Also, the level and penetration of water uptake improved at higher power settings. However all of these plasma polymerized dimethyl sulphate layers were found to be unstable towards solvent washing, FIG. 2 b . This behaviour is analogous to the poor hydrophilicity observed for dimethyl sulphate plasma polymer deposited onto non-porous polypropylene films, FIG. 1 b.
[0061] Argon plasma crosslinking pre-treatment of the porous nonwoven polypropylene films prior to plasma polymerisation of dimethyl sulphate gave rise to a significant improvement in water absorption capacity (up to 600% water uptake by weight), also a corresponding improvement in stability towards propan-2-ol washing was evident, FIGS. 3 a and b . The degree of enhancement critically depends upon the power level settings for both plasma treatment steps. In the case of solvent washing, argon plasma power level was found to be the governing factor at powers greater than 5 W. It is of interest to note that a certain degree of water absorption occurs for just dimethyl sulphate vapour exposure to the argon plasma activated polypropylene surface (whereas there is no water absorption following dimethyl sulphate exposure to unactivated polypropylene).
[0062] For the deposited dimethyl sulphate plasma polymer layers, XPS analysis indicated a strong correlation between the concentration of high oxidation state sulphur species and surface hydrophilicity, as shown in Table 1 and FIG. 4 .
TABLE 1 XPS elemental analysis of dimethyl sulphate plasma polymer deposited onto polypropylene film. Dimethyl sulphate power level % C % O % S 3 60 ± 0.5 29 ± 0.5 8 ± 0.5 5 31 ± 1.0 55 ± 0.6 14 ± 0.5 8 23 ± 0.6 60 ± 0.6 17 ± 0.5 10 19 ± 0.5 63 ± 0.6′ 18 ± 0.5 Theoretical 29 57 14
[0063] The lower binding energy S(2p) peak at 164.8 eV can be assigned to sulphur atoms bonded to one or two oxygen atoms (e.g. sulphur monoxide groups (Structure 2 ), whilst the higher binding energy component at 169.4 eV is typical of sulphate (Structure 1 ) and sulphite (Structure 3 ) environments. The shift towards less oxidised sulphur centres at higher plasma powers was compensated by the emergence of a larger proportion of oxidised carbon species in the C(1s) spectra, FIG. 4 .
[0064] In the case of the porous polypropylene film, stacks XPS verified that the extent of plasma penetration was important, FIG. 5 . Poor penetration occurred at low plasma power settings. Deeper modification was observed for higher plasma power levels, however this was accompanied by poor stability towards solvent washing, FIG. 6 (as seen previously in FIGS. 1 a and b and 3 a and b ). Argon plasma pre-treatment was found to improve the level of sulphur incorporation and stability towards solvent washing, as shown in FIG. 6 and this is consistent with the observed improvement in water absorption properties, as shown in FIGS. 3 a and b.
[0065] Infrared spectroscopy of the dimethyl sulphate monomer gave the following major band assignments: O═S═O antisymmetric stretching (1456 and 1391 cm −1 ), O═S═O symmetric stretching (1199 cm-1), S—O stretching (1004 and 983 cm −1 ) and O—S—O stretching (at 826 and 758 cm-1), FIG. 7 . Dimethyl sulphate plasma polymer layers deposited at both 3 W and 5 W settings gave rise to a prominent unsaturated sulphur bond feature corresponding to sulphite S═O stretching (ca 1225 cm-1), where the splitting (in particular 5 W) may be due to rotational isomerism around sulphite S—O single bonds (Structure 3 ), i.e. the sulphate stretches characteristic of the monomer have disappeared to be replaced by sulphite groups. At higher power levels, (8 W and 10 W), a new sulphur monoxide band appeared at 1168 cm −1 . The presence of a mixture of both sulphite and sulphur monoxide bands at 8 W correlates well with the doublet seen in the S(2p) XPS data at this power setting, FIG. 4 .
[0066] Reflectometer measurements provided values of increasing deposition rates for thin films of the plasma polymers with rising power level settings, Table 2.
TABLE 2 Reflectometer thickness measurements of dimethyl sulphate plasma polymer layers deposited onto polypropylene film. Plasma power Deposition rate level used (W) nm/min 3 17 ± 3.2 5 26 ± 2.4 8 33 ± 2.1 10 39 ± 1.8
[0067] Optical microscopy showed considerable agglomeration of nonwoven polypropylene fibres during the direct plasma polymerisation of dimethyl sulphate at power levels above 5 W, FIG. 8 . Argon plasma cross-linking pre-treatment was found to alleviate this drawback and provided good structural retention of the hydrophilic fibres.
[0068] It is therefore clear from these results that plasma polymerisation of dimethyl sulphate leads to an improvement of surface wettability due to the incorporation of hydrophilic sulfur-containing groups. Low power levels give better structural retention of sulphite groups, FIGS. 4 and 8 . Whilst higher power settings lead to more extensive monomer fragmentation culminating in the incorporation of sulphur monoxide centres. The greater vulnerability of the deposited plasma polymer to solvent removal at high electrical discharge powers can be attributed to the creation and etching properties of atomic oxygen, this can lead to the formation of low molecular weight (loose) material on the surface.
[0069] Noble gas plasma pre-treatment was found to significantly improve the wettability and adhesion of deposited dimethyl sulphate plasma polymer films. This can be explained in terms of crosslinking, and the formation of trapped free radicals at the polyolefin surface. A crosslinked polypropylene surface will be less susceptible towards chain sissions and the formation of low molecular weight material. Whilst the entrapped free radicals at the surface can participate in chemical bonding interactions during subsequent exposure to dimethyl sulphate plasma species.
[0070] In the case of porous non-woven polypropylene substrates, plasma penetration of both argon and dimethyl sulphate plasmas improved at higher power settings, FIGS. 2 and 3 . Under such conditions, more energetic species are generated (greater plasma sheath potential), which are capable of penetrating deeper into the subsurface. Argon plasma pre-treatment (surface crosslinking) in combination with plasma polymerisation of dimethyl sulphate at higher powers (necessary for penetration into the sub-surface) was found to produce the most stable hydrophilic surfaces. This can be attributed to noble gas plasma crosslinking raising the melting temperature of the polypropylene fibre surface, and thereby helping to retain its structural integrity, FIG. 8 . Such hydrophilic surfaces have potential use in filters, adhesion promotion and biocompatibility.
[0071] In a further illustrative example of the application of this invention, polyacrylic acid granules (partially neutralised and slightly crosslinked (5%), ASAP 2000 , Chemdal International Ltd) were placed onto a glass plate (50 mm×15 mm) and placed into a cylindrical glass reactor pumped by mechanical rotary pump via a liquid nitrogen cold trap (base pressure=9×10-3 Torr, an leak rate=4.1×10-9 mol s-1). A copper coil wrapped around the reactor was coupled to a 13.56 MHz radio frequency power supply via an LC matching network. Prior to each experiment, the chamber was cleaned using a 50 W air plasma at 0.2 Torr. Samples were exposed to a source gas, introduced via a fine control needle valve at a pressure of 0.2 Torr, followed by plasma exposure for 5 minutes. Upon completion, the reactor was purged with monomer for 5 minutes.
[0072] Absorption under load (AUL) is a measure of the ability of an SAP to absorb fluid under an applied pressure. The AUL was determined by the following method, as described elsewhere. A sap (0.100 g±0.001 g) was carefully scattered onto a 140-micron, water permeable mesh attached to the base of a hollow plexiglass cylinder with an internal diameter of 25 mm. The sample was covered with a 100 g cover plate and the cylinder assembly weighed (0.28 psi). This gives an applied pressure of 20 g cm-2 (0.28 psi). The screened base of the cylinder was placed in a 100 mm petridish containing 25 ml of a test solution, and the polymer was allowed to absorb for 1 hour. By reweighing the cylinder assembly, absorption under load (AUL) at the given pressure was calculated by dividing the weight of the liquid absorbed by the dry weight of the polymer before liquid contact. Test solutions used were distilled water, 0.9% saline solution and a 0.9% ammonia solution both to show the effects of salt poisoning and the uptake of materials such as urine, blood etc.
[0073] ATR-FTIR was used to probe the plasma treated polymer granules on a Perkin Elmer Spectrum One FTIR instrument at a resolution of 4 cm-1 and averaged over 64 scans between 4000-700 cm-1 using a liquid nitrogen cooled MCT detector.
[0074] Poor absorbency of the lightly crosslinked partially neutralised polyacrylic acid untreated material towards electrolyte containing liquids was found by comparing deionised water with saline and ammonia solutions, FIG. 11 . 105.6 g of deionised water was found to absorb per gram of polymer at 0.28 psi. In contrast, the same material was only capable of absorbing 29.7 g, and 23.5 g of the saline and ammonia solutions at 0.28 psi, respectively. This dramatic decrease in absorption is attributed to the salt poisoning effect.
[0075] Argon plasma treatment of the polyacrylic acid produced an increase in absorptive capacity, FIG. 9 . However, the individual levels of absorption for both the saline and ammonia solutions remained significantly lower than corresponding distilled water absorption levels (i.e. the salt poisoning effect alas still present).
[0076] In the case of nitrogen plasma treatments, the absorption properties as measured by AUL were divergent, FIG. 10 . The absorption capacity of distilled water remained unaffected by the action of nitrogen plasma. However, substantial increases in performance of the absorptive capacity of polyacrylic acid with respect to both saline and ammonia solutions were found, FIG. 11 . The maximum absorptions (96 g/g and 79 g/g for ammonia and saline solutions respectively) are comparable to the performance obtained using distilled water indicating that the salt poisoning effect had been overcome. It is of relative interest to note that the rate of ammonia absorption improves to that of saline solution under the action of nitrogen plasma.
[0077] A combination of argon plasma pre-treatment at 20 WU for 5 minutes, followed by nitrogen plasma treatment indicated further improvements of the absorptive capacity of the SAP materials, FIG. 12 . The effect of overcoming the salt poisoning effect and enhancing the absorption due to crosslinking generates materials that can be termed and used as SAPS.
[0078] The absorption measurements of SAPS that overcome the salt poisoning effect by modification using a nitrogen plasma is supported by infrared data, FIG. 12 . The emergence of antisymmetric and symmetric carbonyl salt peaks at 1540 cm-1 and 1410 cm-1 respectively for nitrogen plasma treated polyacrylic acid is contrasted with the substantially reduced carbonyl stretching for the untreated polyacrylic acid at 1706 cm-1. The generation of salt peaks under the action of nitrogen plasma is attributable to the incorporation of ammonium counter ions coordinated around the carboxylic acid centres, effectively generating a neutralised salt of polyacrylic acid with a basic form.
[0079] The production of SAPs that overcome the salt poisoning effect and can have enhanced absorptive capacity under pressure is possible without the use of conventional chemical additives such as ion exchangers or surfaces crosslinkers which dilute the properties of the SAPS. Plasma modification of polyacrylic aids using argon and/or nitrogen gas can generate SAPs that substantially reduce the salt poisoning effect even under pressure.
[0080] In a yet further utilisation of the invention small (6 cm×2 cm) strips of non-porous (capacitor grade, ICI, 0.5 μcm thickness, Corovin GmbH) polypropylene film were cleaned in non-polar (cyclohexane) and polar (propane-2-ol) solvents and then dried in air. For the porous material, 8 sheets were stacked to give an overall thickness of 1 mm in order to investigate the extent of plasma penetration.
[0081] Radio frequency (RF) power at 13.56 MHz was applied through a copper cil wound around the outside of a tubular glass reactor (3 dm3 volume capacity, with an inner diameter of 5 cm and a length of 68 cm). A Faraday cage was placed around the apparatus to prevent the leakage of stray electromagnetic radiation. A typical experimental run comprised evacuating the plasma chamber to a base pressure of 2×10-3 mbar using a liquid nitrogen trapped mechanical rotary pump. Feed gas was then introduced at 0.2 mbar pressure and the electrical discharge ignited. Plasma exposure time was kept constant at 5 mins in all cases. Both the influence of argon plasma pre-treatment, and subsequent air plasma exposure were investigated in terms of power settings.
[0082] Sessile drop water contact angle measurements were carried out on the non-porous polypropylene films using a video capture apparatus (AST Products Inc. VC2500). Each contact angle value was taken for a 2 μl drop of high purity water syringed onto the surface.
[0083] In the case of the porous polypropylene film substrate bulk water absorption was used to determine the change in wettability. A 0.625% wt blue dye aqueous solution of Coumarin 47 (Parker Pen Company) was used as the probe liquid. UV absorption measurements were taken for each layer in the stack using a UV-VIS Spectrophotometer UNICAM UV4. This comprised immersion of the plasma treated sheet into 1 ml of the aqueous dye solution. Any remaining excess liquid was then combined with water to make a 1 ml aliquot, and this was analysed by UV-VIS absorption spectroscopy at 200 nm (this wavelength corresponds to dye absorption). By referencing to a set of known concentration calibration solutions, it was possible to determine the water absorption capacity of the plasma treated porous films as a percentage of the polymer mass prior to soaking.
[0084] The stability of the plasma modified samples towards hydrophobic recovery was evaluated by rinsing them in propan-2-ol in order to remove any low molecular weight oxidised material generated at the surface, followed by re-evaluation of surface wettability.
[0085] A VG ESCALAB spectrometer equipped with an unmonochromatised Mg Ka X-ray source (1253.6 eV), and a concentric hemispherical analyser was used for surface analysis by X-ray photoelectron spectroscopy (XPS). Elemental sensitivity (multiplication) factors were taken as being O(1s): C(1s) equals 0.45:1.00.
[0086] In the case of the non-woven porous polypropylene films, the morphological nature of the constituent fibres was examined by optical microscopy. An Olympus BX40 optical microscope equipped with a digital camera and a fibre optic light source (Euromax) was used for image capture.
[0087] A series of results were analysed as is now described.
[0000] (a) Flat Polypropylene Film
[0088] A water contact angle value of 95±3° was measured for the untreated non-porous polypropylene film surface. In the case of straightforward air plasma treatment, the contact angle was found to decrease with increasing power, to eventually reach a minimum of 45° at 20 W (higher power levels caused physical damage to the samples) as shown in FIG. 13 a . Washing the plasma modified polymer surfaces in propan-2-of gave rise to the loss of hydrophilicity, with the water contact angle value becoming reminiscent of that associated with untreated polypropylene film as shown in FIG. 13 b.
[0089] In the case of argon plasma, pre-treatment followed by air plasma oxidation, provided two beneficial effects. Firstly, an improvement in surface wettablity, FIGS. 13 a and b . Also, argon plasma crosslinking improved the stability of the oxidised surface towards solvent washing (hydrophobic recovery). Control experiments comprising just argon plasma exposure were found to be not as effective (in this case free radical sites at the plasma modified surface undergoing oxidation upon exposure to air); however these oxidised surfaces were also stable towards hydrophobic recovery. The extent of argon plasma crosslinking (i.e. argon plasma power level) was found to govern the stability towards hydrophobic recovery following air plasma exposure.
[0000] (b) Porous Polypropylene Sheet
[0090] The stabilising influence of argon plasma pre-treatment upon the hydrophilicity of air plasma modified polypropylene surfaces was further investigated by examining porous non-woven substrates. Dye absorption measurements showed that the poor retention of hydrophilicity previously seen for the flat films following air plasma treatment and solvent washing was also evident for these porous substrates, FIG. 14 . It is of interest to note that for just air plasma exposure, hydrophilic incorporation occurred in a fairly uniform manner with depth down to 8 layers (1 mm), FIG. 14 . This data is consistent with a large penetration depth of plasma species into the porous substrate. A slight reduction (from 17% to 13%) was observed at very low powers (5 W) where the density of energetic particles becomes a limiting factor. Propan-2-ol solvent washing of the modified substrate produced a significant drop in water absorption to approximately 5% (this is close to the untreated value of 0%). This behaviour is analogous to the corresponding investigation undertaken with the flat non-porous polypropylene films.
[0091] In the case of argon plasma, crosslinking prior to air plasma treatment, a significant improvement in water absorption was found both prior to and following propan-2-ol washing, as shown in FIGS. 15 a and b . In the former case, there is a good correlation between both air and argon plasma power level and the amount of water absorption. Whilst only the power input for argon plasma treatment appeared to influence retention of hydrophilicity subsequent to propan-2-ol washing. Control experiments using just argon plasma treatment (i.e. Air power level=0 W) exhibited much lower levels of surface modification with stability towards hydrophobic recovery during solvent rinsing.
[0092] XPS analysis showed that a good correlation exists between surface hydrophilicity and O/C atomic ratios, as shown in FIG. 16 . A significant improvement in O/C ratio was noted for the two-step plasma treatment, thereby confirming the importance of argon plasma crosslinking.
[0093] Optical microscopy of the untreated polypropylene non-woven film showed the presence of randomly orientated fibres, as illustrated in FIG. 17 . In the case of just air plasma treatment, the fibre surface becomes etched and parts of the film appear highly densified due to localised melting. The extent of damage was found to correspond to the air plasma power level setting. Argon plasma crosslinking pre-treatment alleviated deterioration of the substrate. In this case, the fibres retained the structure previously identified for the untreated non-woven surface.
[0094] For just air plasma modification, the surface wettability of polypropylene can be unstable and easily removed by solvent washing. This can be attributed to the formation of a layer of oxidised low molecular weight material on the surface generation by polymer chain scission.
[0095] Noble gas plasma treatment of polymeric materials comprises interactions of energetic particles and electromagnetic radiation with the surface. Some of the photons possess sufficient energy to break chemical bonds in the surface region and create radicals, which subsequently undergo cross-linking. Any trapped radicals become oxidised upon exposure to air leading to an improvement in surface wettability with low hydrophobic recovery. This can be ascribed to a partially oxidised and crosslinked surface layer.
[0096] Argon plasma exposure prior to air plasma treatment imparts two major benefits on surface hydrophilicity. Firstly, there is an enhancement in water contact angle and absorption values compared to just straightforward air plasma, exposure. Also it permits air plasma treatment to be carried out at higher power levels without causing surface damage. Crosslinking of the polymer surface in this manner helps to retard the effects of oxidative degradation and formation of mobile low molecular weight species commonly associated with air plasma treatment. Similar improvements in hydrophilicity were found for other combinations of crosslinking gases (e.g. N2, He, Ne, Xe and Kr) and oxidising gases (e.g. O2, CO2 and H2O).
[0097] Wettability measurements and XPS data confirm that plasma penetration extends throughout several layers of the porous polypropylene substrate. Once again, argon plasma pretreatment significantly improves the hydrophilic stability of the surface. Optical microscopy revealed that air plasma exposure alone causes fibre agglomeration attributable to thermal damage. Whereas argon plasma treatment helps to raise the melting temperature of the fibre surfaces via crosslinking, thereby improving their structural integrity. The ability to incorporate hydrophilic groups throughout porous polymer structures is of potential commercial interest for applications such as diapers, filters, solid phase organic synthesis, and catalyst supports.
[0098] The wettability and stability towards hydrophobic recovery of plasma oxidised polymer surfaces can be significantly improved by using an argon plasma pre-treatment to cross-link the surface. This stabilises the surface against thermal degradation and the formation of low molecular weight oxidised species.
[0099] The wettability and stability of dimethyl sulphate plasma polymer films deposited onto polypropylene surfaces can be significantly improved by the use of an argon plasma crosslinking pre-treatment. The latter stabilises the polyolefin surface against thermal degradation and the formation of poorly adhered low molecular weight oligomeric species.
[0100] The two-step sequence of plasma treatments gives rise to stable-wettable polymer surfaces. This entails crosslinking the surface first, followed by the deposition of hydrophilic species. The contact angle, XPS and FTIR measurements all indicate that these surfaces are stable towards hydrophobic recovery and in the case of porous substrates, both the exterior and interior interstitial surfaces can be modified by this method to yield high capacities for water absorption.
[0101] By adopting the pre-treatment step (i) comprising plasma crosslinking, the polymer substrate is stabilised prior to plasma polymerisation. Extension of these examples of the invention to porous polymer films is shown to produce a significant rise in total water absorption capacity and thus the modification steps of this invention provide significant advantages and improvements in the provision of material with super absorption characteristics. Although the invention relates to the particular advantages to be gained with super absorption materials it should be appreciated that the method and steps thereof as herein described can be of use with other forms of materials and therefore can be used as required to give required advantages. | The invention relates to a method of altering the characteristics of a material, by applying one of, but preferably both of the steps of cross-linking of either or both the exterior and internal surfaces of the substrate and/or plasma modification or plasma deposition of/onto the cross-linked material. When both steps are performed the substrate which can, for example, be an absorbent, hydrophobic polymer material has improved liquid retention and super absorbence characteristics. | 1 |
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a machine for producing fiber-containing web material, in particular tissue paper, comprising a permeable dewatering belt for transporting fiber-containing source material used for producing web material from a forming section to a suction/pressing section as well as a press belt arrangement assigned to the suction/pressing section, the source material being received in the suction/pressing section between the press belt arrangement and the dewatering belt and the press belt arrangement pressing the source material and the dewatering belt against a suction arrangement of the suction/pressing section.
The invention further relates to a press belt for producing fiber-containing web material, in particular tissue paper, in particular in a machine comprising a permeable dewatering belt for transporting fiber-containing source material used for producing web material from a forming section to a suction/pressing section as well as a press belt arrangement assigned to the suction/pressing section, the source material being received in the suction/pressing section between the press belt arrangement and the dewatering belt and the press belt arrangement pressing the source material and the dewatering belt against a suction arrangement of the suction/pressing section.
US 2007/0068645 A1 discloses a machine for producing fiber-containing web material, in particular so-called tissue paper. Such tissue paper, when compared with paper used as writing material or packaging material, for example, has a considerably higher pore volume proportion or heavier surface texturing, for example in order to achieve better absorbency and better wiping performance for domestic use. The general principle of US 2007/0068645 will now be described below with reference to FIG. 1 of the present application. In order to obtain this structure of the tissue paper, in the prior art machine 10 , the source material, that is to say the pulp, for the web material to be produced is deposited in a forming section 12 on a dewatering belt 14 that is embodied in endless configuration, for example designed as a so-called forming fabric, and is moved in a transport direction L over a suction device 16 arranged on the rear side of the dewatering belt 14 in the direction of a suction/pressing section 18 . This suction/pressing section 18 comprises a press belt arrangement 20 with two press belts 22 , 24 nested inside one another. The source material for the web material 26 to be produced is received in a sandwich-like manner between the outer of these two press belts, that is to say the press belt 22 , and the dewatering belt 14 , in the suction/pressing section 18 . In this configuration, the source material is able to move via a suction arrangement of the suction/pressing section 18 which is generally designated with 28 . This suction arrangement 28 can comprise a roll-like element, for example, on the internal volume region of which a negative pressure is produced in order to extract liquid, in general water, from the source material and through the dewatering belt 14 . After passing through the suction/pressing section 18 , the web material 26 to be produced is moved through a press nip 28 between the suction/pressing arrangement 18 and a drying cylinder or Yankee cylinder 30 .
A significant influence is made on the structuring or texturing of the web material 26 in the suction/pressing section 18 . For this purpose, the dewatering belt 14 can be provided, for example, with a comparatively coarse, rough or heavy surface-structured form, for example a woven-fabric belt. In the press belt arrangement 20 the press belt 22 provided externally essentially assumes the task of producing a surface texturing in the web material 26 . The press belt 24 running inside the press belt 22 and guided together with it in some areas over deflection rollers is essentially intended to provide the necessary contact pressure against the suction arrangement 28 . For this purpose, this press belt 24 can be subjected to a tension of up to 8 kN/m, for example.
In this familiar machine 10 , the tasks of producing a texturing of the web material 26 on the one hand and of producing the necessary contact pressure on the other hand are divided between two press belts.
BRIEF SUMMARY OF THE INVENTION
The object of the present invention is to make available a machine for producing fiber-containing web material, in particular tissue paper, by means of which, with a simplified construction in particular in a suction/pressing section, the structuring of the produced web material can be influenced in a defined manner.
According to the invention, this object is accomplished by a machine for producing fiber-containing web material, in particular tissue paper, comprising a permeable dewatering belt for transporting fiber-containing source material used for producing web material from a forming section to a suction/pressing section as well as a press belt arrangement assigned to the suction/pressing section, the source material being received in the suction/pressing section between the press belt arrangement and the dewatering belt and the press belt arrangement pressing the source material and the dewatering belt against a suction arrangement of the suction/pressing section.
It is also proposed that the press belt arrangement comprises a single press belt providing a source material contact surface.
In the construction according to the invention for the production of tissue paper or in a machine intended for that purpose, only a single press belt is used in the suction/pressing section, rather than a plurality of press belts that are nested inside one another and in each case take on subtasks. This provides both the source material contact surface and the necessary contact pressure against a suction arrangement of the suction/pressing section. The construction of the press belt arrangement or the suction/pressing section can be greatly simplified in this way, since only a single press belt and consequently driving or deflection elements for only a single press belt must be provided.
Especially if a web material with a comparatively fine surface structure, that is to say smoother tissue paper, is to be produced with the machine according to the invention, it is proposed that the press belt is constructed from yarn or/and fibrous material in the region of its source material contact surface, of which at least 60%, preferably at least 80%, and most preferably approximately 100%, exhibits a fineness of between 44 dtex and 1.7 dtex, preferably at most 17 dtex, and more preferably at most 11 dtex or at most only 6 dtex, and quite preferably at most 3 dtex. This ensures that a comparatively large proportion of the yarn or fibrous materials that are present in the region of the source material contact surface exhibits a comparatively high fineness, which results in a correspondingly fine structuring of the web material. A homogeneous transfer of pressure through the structure can be achieved by the appropriate choice of the yarn or fibrous material.
As an alternative or in addition, it can also be proposed for this purpose that the press belt is constructed with yarn or/and fibrous material in the region of its source material contact surface, of which at least 60%, preferably at least 80%, and most preferably approximately 100%, has a minimum cross-measurement of at most 70 μm, preferably at most 27 μm, and even more preferably at most 23 μm, and most preferably at most 13 μm. With such a fine structuring of the press belt on its source material contact surface, importance is attached less to the attainment of the heaviest possible texturing of the web material to be produced, and more to the dewatering performance in the region of the suction/pressing section, so that a very high proportion of the liquid contained in the source material for the web material can already be obtained at that point.
This comparatively fine surface structure of the press belt, albeit with high tensile strength, for the generation of the necessary contact pressure can be obtained by the press belt comprising a basic structure and at least one support layer on the basic structure, the source material contact surface being provided on a support layer.
In order to arrange a single press belt in a constructively simple manner in a suction/pressing section in the embodiment of a machine according to the invention in such a way that, on the one hand, it is able to generate the desired surface texturing in the web material to be produced, and, on the other hand, it also exhibits the necessary strength, it is proposed that the press belt comprises a basic structure in the form of a porous textile surface construction, whereby the basic structure can be constructed especially from:
a woven fabric, or/and a laid scrim, or/and a warp-knitted fabric, or/and a spiral link structure, or/and a gauze fabric, or/and a film.
A construction for taking up the load or a significant part of the load that is present in a longitudinal direction of the belt, which also experiences a comparatively small elongation under heavy tensile loading and consequently ensures constant pressing conditions throughout the operational life, is provided with embodiments of this kind of the basic structure. It should be made clear at this point that the basic structure can, of course, also comprise a plurality of layers of the previously described type of construction. In the case of a construction as a woven fabric, for example, the woven fabric itself can thus be of multi-layer construction, that is to say, for example, with a plurality of layers of threads running in a longitudinal direction or/and with a plurality of layers of threads running in a transverse direction. Combinations of different structures are also possible. The use of a film having defined or undefined openings for producing fluid permeability is in fact in pronounced contrast with the use of a woven fabric. Even if the properties are different, however, the use of a film offers entirely characteristic advantages compared with a woven fabric.
If it is wished to obtain a comparatively coarse texturing of the web material to be produced, it is advantageous if the basic structure provides the source material contact surface.
As previously explained, in the construction according to the invention, the single press belt that is present there in a suction/pressing section must also take up the prevailing tensile loading, in particular in the longitudinal direction of the belt, in order to provide the necessary contact pressure. It is advantageous for this purpose if the basic structure is designed with structural elements with polyester material, preferably PET material, or/and PA material or/and PEEK material. The materials Nomex, Kevlar and related types of material also offer considerable advantage here. These are construction materials, which also experience a relatively small longitudinal elongation in the presence of comparatively heavy tensile loading and consequently ensure constant working conditions consistently throughout the operational life. In this case, every single one of the aforementioned materials has its own characteristic advantages, although these must be bought in part, however, at the expense of other disadvantages or particularly high costs.
In particular when the basic structure is constructed with threads, that is to say, for example as a woven fabric, a laid scrim or a warp-knitted fabric, these threads can be constructed as monofilament yarns, multifilament yarns or twines or combinations thereof.
In order to influence the texturing of the web material to be produced or/and the air permeability of the individual press belt to be provided in a suction/pressing section according to the invention, it is further proposed that at least one support layer is present on the basic structure, the source material contact surface being provided on a support layer. Provision can be made in this case, for example, for at least one support layer to be configured with:
a fibrous material layer, a laid scrim layer, a membrane layer.
It should be made clear at this point that combinations of a plurality of supporting layers, possibly including layers of different embodiments, are also possible here, of course.
In order further to increase the structural strength of the press belt, in particular in a longitudinal direction of the belt, it is proposed that at least one support layer comprises structural strength elements running in a longitudinal direction of the belt. These can be laid scrim yarns, for example, in an embodiment as or with a laid scrim running in a longitudinal direction of the belt. In an embodiment as or with a membrane, yarns or threads can be incorporated into into the membrane, which then preferably also extend in the longitudinal direction of the belt.
Especially the dewatering performance in the suction/pressing section can be influenced by coating or/and impregnating at least one support layer at least in some areas with a permeability influencing material.
In order to obtain a comparatively high dewatering performance, it is further proposed that the press belt has an air permeability of at least 15 cfm, more preferably at least 20 cfm, or at least 25 cfm, it being preferable for the permeability to air even to lie in a region of at least 50 cfm and ideally even at least above 80 cfm. A comparatively high air permeability ensures that, as a result of the high air throughput, a correspondingly high proportion of liquid can also be extracted from the construction material.
In order to be able to adjust the dewatering performance in a particularly advantageous manner with the single press belt intended to be used according to the invention, it is proposed that the press belt has an air permeability of at the very most 1200 cfm, at most 700 cfm to 800 cfm, preferably at most 500 cfm to 600 cfm, and most preferably in the range of 200 to 400 cfm.
In order, throughout the operational life, on the one hand to obtain a uniform structuring or texturing of the web material to be produced, and on the other hand to press out the liquid contained therein, it is proposed that the press belt exhibits a tensile strength in a longitudinal direction of the belt of at least 20 kN/m, preferably at least 50 kN/m, and most preferably at least 70 kN/m. In the case of such high tension ranges, and at any rate novel tension ranges in the paper industry, a person skilled in the art will naturally no longer think about the production of particularly voluminous fibrous material webs, in particular tissue webs. It has emerged as a complete surprise, however, in the course of experiments that particularly soft and fluffy, yet durable, tissue webs can be produced under this extreme pressure.
A further influence on the surface texturing of the web materials to be produced can be achieved in that the press belt exhibits a source material contact surface of at least 15%, preferably at least 25%, and most preferably at least 30%.
It should be made clear at this point that the source material contact surface is the surface area in relation to the entire surface area of the press belt which, in the suction/pressing section, enters into pressing contact with the web material to be produced or with the source material for that purpose. These are in particular the regions of the surface area, in which prominent protrusions are present in the press belt in the direction of the source material, for example at bending points of the yarns that are present in a woven fabric structure.
For the purpose of lowering the viscosity of the liquid to be removed in a suction/pressing section, it is possible among other things to proceed with the use of hot air, which is sucked through the press belt, the source material and the dewatering belt by means of the suction arrangement. In order to avoid structural damage to the press belt in the course of the thermal interaction with this air, it is proposed that the press belt is temperature-stable up to a temperature of 70° C., preferably 80° C., and most preferably 90° C. This means that, for the limit value indicated in each case, the construction material of the press belt is present in a configuration that remains essentially unchanged by comparison with lower temperatures and, in particular, is not transformed into a free-flowing state configuration.
It is advantageous, furthermore, if the press belt has a thickness of at most 5 mm, preferably at most 3 mm, and most preferably at most 2 mm.
The object of the invention is accomplished, furthermore, by a press belt for producing fiber-containing web material, in particular tissue paper, in particular in a machine comprising a permeable dewatering belt for transporting fiber-containing source material used for producing web material from a forming section to a suction/pressing section, as well as a press belt arrangement assigned to the suction/pressing section, the source material being received in the suction/pressing section between the press belt arrangement and the dewatering belt and the press belt arrangement pressing the source material and the dewatering belt against a suction arrangement of the suction/pressing section, in such a way that it is characterized in that the press belt has a tensile strength of at least 20 kN/m, preferably at least 30 kN/m, even more preferably at least 50 kN/m and most preferably at least 70 kN/m in a longitudinal direction of the belt, and comprises a source material contact surface.
The press belt advantageously exhibits an air permeability of at least 15 cfm, preferably at least 50 cfm, and most preferably at least 80 cfm.
In other cases it may be be preferable, on the other hand, for the press belt to exhibit an air permeability of at the very most 1200 cfm, of at most 700 cfm to 800 cfm, preferably at most 500 cfm to 600 cfm, and most preferably in the range of 200 to 400 cfm.
Since, on the one hand, a minimum value and, on the other hand, a maximum value is described, a combination of both guidelines is naturally also possible.
It is also preferable for the press belt to be suitable for operation as a single press belt inside a press belt arrangement assigned to a suction/pressing section.
The corresponding advantages of a press belt according to the invention can be found from the description of the invention in conjunction with the claimed machine, and there is no need for them to be repeated here unnecessarily. It goes without saying that the claimed press belt for achieving the advantages described at the appropriate points can also be modified according to the other preferred embodiments of the machine according to the invention.
In summary, it can thus be established that the invention makes available a machine and a press belt for producing web materials, in particular tissue webs, which permit the tissue web to be processed inside a press section by a single press belt, which provides a source material contact surface. The press belt can have at least one support layer, which comes into contact with the web to be processed or produced or can consist solely of a basic structure, which then also provides the source material contact surface. If the press belt includes a supporting layer, so that it can be identified as a press felt, it should preferably be characterized by a minimum permeability of at least 15 cfm. If the press belt is a belt or, as the case may be, a screen that is characterized by an uncoated basic structure, it is preferable for the press belt to have a maximum permeability of 1200 cfm.
In both cases, however, it is characteristic of especially preferred embodiments of the invention that the press belt can be operated under high tensile loads of more than 20 kN/m and, in entirely preferred embodiments, even up to and beyond 70 kN/m inside a machine and in contact with a material web to be produced. What is more, the press belt also automatically exhibits, in addition to the already described source material contact surface, a contact surface in direct contact with the machine as a single press belt that is present inside a press belt arrangement.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
The present invention is described in detail below with reference to the accompanying figures, in which:
FIG. 1 depicts a representation in principle of the construction of a machine that is known from the prior art for producing in particular tissue paper;
FIG. 2 depicts an embodiment according to the invention of a suction/pressing section of a machine for producing web material, in particular tissue paper;
FIG. 3 depicts a cross section of a press belt used in the suction/pressing section in FIG. 2 .
DESCRIPTION OF THE INVENTION
The construction of a machine for producing web material, in particular tissue paper, embodied according to the invention is described below with reference to FIGS. 2 and 3 , whereby the fundamental construction of a machine 10 of this kind can be effected in a manner as illustrated in FIG. 1 and described above. Essential aspects for the explanation of the principles of the present invention are illustrated In FIGS. 2 and 3 .
FIG. 2 depicts the suction/pressing section 18 of a machine 10 constructed according to the invention with the press belt arrangement 20 provided therein. In contrast to the characterizing features that are familiar from the prior art, in which both of the press belts 22 , 24 nested inside one another that are distinguishable in FIG. 1 are used, only a single press belt 32 is proposed in the construction according to the invention. This is guided over a plurality of deflection rollers or drive rollers 34 , 36 , 38 , 40 , in such a way that, in a peripheral region of the suction arrangement 28 , it presses the source material for the web material 26 to be produced and also the dewatering belt 14 against the outer periphery of the same. It should, of course, be made clear at this point that the geometrical configuration that can be appreciated in FIG. 2 , which is produced essentially through the positioning of the various rolls 34 to 40 , could be provided in some other way.
The fact that the press belt arrangement 20 in the construction according to the invention comprises only a single press belt 32 , means that its embodiment is significantly more cost-effective, since not only a single belt needs to be provided, but also the deflection rollers or drive rollers for only a single belt need to be provided.
In order to be able to meet the requirements which arise during operation with this single press belt, the latter is configured in the manner described below. These requirements comprise the provision of an adequately high contact pressure, with which the source material for the web material 26 together with the dewatering belt 14 is pressed against the outer periphery of the suction arrangement 28 . This means that the single press belt 32 must exhibit an adequately high tensile strength to assure an adequate stability with the smallest possible longitudinal elongation throughout the operational life, including under corresponding tension. For this purpose the press belt 32 can be provided with a tensile strength, which in the ideal case amounts to at least 30 kN/m, in order to be able to mount it in the suction/pressing section with adequate tension. It is preferable, however, that the aforementioned 30 kN/m tensile strength is considerably exceeded by the press belt according to the invention and that it withstands a continuous tensile loading of more than 50 kN/m or even more than 70 kN/m.
The single press belt 32 must, in addition to the tensile strength previously mentioned above, also exhibit a corresponding texture on its source material contact surface 42 situated externally in FIG. 2 , especially if comparatively heavy texturing of the same takes prominence during the production of the web material 26 . This structure of the press belt 32 is transferred in the course of the sandwich-like accommodation of the source material between the latter and the dewatering belt 14 on the source material and is as such reproduced at least partially in the web material 26 .
One example of the construction of the press belt 32 is described below with reference to FIG. 3 .
A cross section, that is to say a section through the press belt 32 in a transverse direction of the belt Q, is illustrated in the form of a detailed enlargement in FIG. 3 . It should be pointed out that the longitudinal direction of the belt is positioned orthogonally to this transverse direction of the belt Q and, in the representation in FIG. 3 , is accordingly positioned orthogonally in relation to the plane of the drawing. This longitudinal direction of the belt also corresponds to the transport direction L that can be identified in FIG. 1 , but without intending to make any statement about its orientation.
The press belt 32 has a basic structure 44 as an essential part of the system, in particular providing the necessary tensile strength in a definitive manner. This is constructed in the illustrated example as a woven fabric having longitudinal threads 46 running in the longitudinal direction of the belt and transverse threads 48 interwoven therewith and extending in the transverse direction of the belt Q. For example, the longitudinal threads 46 can be warp threads and the transverse threads 48 can be weft threads. This embodiment is particularly useful when the basic structure 24 is not produced in an endless manner, but is woven as a belt section having end areas which require to be connected together. The longitudinal threads 46 can also be the weft threads and the transverse threads 48 can also be the warp threads, especially when the basic structure 44 is required to be provided as an endless structure already in the weaving process.
The weave for the basic structure 24 can be selected freely. Especially in the case of a corresponding strength requirement, a plurality of woven fabric layers can also be connected together structurally. The use of so-called gauze fabric is also conceivable. The weave can be open or endless, for example.
As an alternative to the construction of the basic structure 44 as a woven fabric, this could also be constructed, for example, as a spiral or helical twisted yarn or laid scrim, whereby, as a result of this spiral or helical twisting, the one or more yarns providing the basic structure 44 also extend essentially in the longitudinal direction of the belt and in so doing ensure its structural strength. The use of a warp-knitted fabric as a basic structure is also conceivable, and likewise the use of a so-called spiral link structure or spiral screen structure. At the same time, spiral or helically twisted spiral members extending in the transverse direction of the belt Q are arranged overlapping one another and are bound together by connecting threads or wires engaging in the overlapping region in the manner of a chain structure.
Because of its high tensile strength, polyester material in particular, for example PET material, is particularly advantageous as a construction material for the structural elements, that is to say threads or yarns or spiral members of the basic structure 24 . As an alternative, it is also possible to use PA material, PEEK material or other suitable materials, in particular such as the aforementioned Nomex or Kevlar materials. A further advantage of this construction material, in addition to the achievement of a correspondingly high tensile strength, lies in the fact that it is temperature-stable at temperatures of up to 90° C., that is to say it experiences only a very small change influencing the strength of the same. This is important because of the possibility of using hot air in a suction/pressing section 18 intended for improving the dewatering performance, which can lead to corresponding heating of the press belt 32 .
Furthermore, yarns or threads can be used as monofilaments, multifilaments or twines in the construction of the basic structure 44 . Combinations of these types of yarn or thread are also possible, so that the longitudinal threads 46 and the transverse threads 48 , for example, are of different execution in respect of their structure or/and also their construction material. Different woven fabric layers can also be configured with different types of yarns or construction materials in the case of a multi-layered construction, for example a woven fabric structure.
If, in the case of a machine 10 constructed according to the invention, a comparatively coarse structure of the web material 26 to be produced is required to be achieved, the press belt 32 can be constructed, for example, in such a way that the source material contact surface, that is to say the surface of the same, with which the source material introduced via the dewatering belt 14 comes into contact or is pressed against the dewatering belt 14 , is provided by the basic structure 44 . This means, for example, that the press belt 32 comprises only the basic structure 44 . If necessary, this could be coated on its running side, that is to say on the side which lies remote from the source material, with at least one layer for increasing the resistance to wear.
Making the source material contact surface available on the basic structure 44 itself ensures that the press belts, for example in the region of the bending points of the interwoven yarns or threads, are impressed into the source material and consequently lead to a comparatively heavy texturing of the same.
It is also possible in such an embodiment of the press belt 32 with a comparatively strongly structured source material contact surface to ensure that the contact surface, with which the source material makes contact and is pressed directly against the dewatering belt 14 , can lie in the range of 30% and above of the entire surface of the press belt 32 .
In order to achieve a rather finer texturing of the web material 26 to be produced with the construction according to the invention, it is possible to provide at least one support layer on the basic structure 44 . In the example illustrated in FIG. 3 , four support layers of this kind in total are present, of which the layering or also the provision are shown here only by way of example.
Provided immediately after the basic structure 44 is a support layer 50 of membrane-like configuration. This can fundamentally comprise a lattice-like structure with, for example, polygonal, preferably rectangular or square mesh openings 52 , in order to achieve the necessary air permeability. Elliptical, in particular circular, mesh openings or irregularly shaped mesh openings are also conceivable. Yarns 56 can be provided as the structural strength elements for increasing the longitudinal strength in the grid bars 54 extending in the longitudinal direction of the belt, which in turn can be configured as monofilaments, multifilaments or twines, for example.
The previously mentioned materials, in particular polyester material, such as PET material, can thus also be used for the construction of the support layer 50 with membrane-like configuration.
A support layer 58 configured with fibrous material is provided following the membrane-like support layer 50 . This can be in the form of a nonwoven fabric or can be constructed with so-called staple fibers, the fibrous material that is used for this purpose itself being capable of being constructed with the previously mentioned construction materials, preferably polyester material. A support layer 64 configured as a laid scrim lies between this support layer 58 constructed with fibrous material and a further support layer 62 of a fibrous material providing the source material contact surface 42 . This is provided on the adjacent boundary regions of the two support layers 58 , 62 constructed with fibrous material or is received between these two support layers. This support layer 64 configured as laid scrim comprises a multiplicity of yarns or yarn sections 66 extending in the longitudinal direction of the belt, whereby the technical realization in this case too can also be effected with a spiral or helical configuration. This support layer 64 with the thread or yarn sections 66 extending essentially in the longitudinal direction of the belt also increases the structural strength in the longitudinal direction of the belt.
The strong cohesion of the various support layers 50 , 58 , 62 and 64 with one another and also with the basic structure 44 can be effected, for example, by needling. Other physical and/or chemical connection mechanisms, such as sewing or adhesive bonding, are also possible. It can also be of considerable advantage if the support layers 50 , 58 , 62 and 64 are connected with one another, the basic structure is connected in itself and/or both types are connected together by welding, in particular by ultrasonic welding. Ultrasonic welding permits high-precision processing, which was previously considered to be unsuitable, in particular in conjunction with the processing of supporting layers, but is especially preferred in conjunction with the present invention because of the desired extremely high tensile strengths in the press belt.
FIG. 3 illustrates, for instance and rather schematically, the construction of two different preferred embodiments.
In the first preferred embodiment it is preferably further provided in the case of the press belt 32 for the support layer 62 providing the source material contact surface 42 to be constructed with threads or fibers having a fineness of at most 6 dtex, preferably at most 3 dtex, whereby it is possible here to take account of the fact that, for example, a major proportion of these fibers, that is to say for example at least 60%, and preferably at least 80% thereof, are provided with the corresponding fineness. This corresponds, for example, to the use of fibers, of which the minimum cross-measurement is at most 70 μm, preferably at most 27 μm, and most preferably at most 23 μm. It should be made clear at this point that the minimum cross-measurement corresponds to the diameter, for example in the case of a circular cross section and, in the case of elliptical cross section geometry, corresponds to the minimum cross-measurement of twice the small half-axis of the ellipse. This means that, according to the invention, it is ensured that the surface roughness on the source material contact surface 42 is achieved with threads or fibers with a maximum of 3 dtex, for example.
It is also possible with the previously described construction, in particular the fineness of the supporting layer, which also provides the source material contact surface 42 , to ensure an adequately high through-flow capability, that is to say permeability to air. This can lie in a region of at least 15 cfm, more preferably at least 20 cfm, or at least 25 cfm, whereby it is preferable that the permeability to air even lies in a region of at least 50 cfm and ideally even at least above 80 cfm, so that relatively high requirements are imposed in respect of the air permeability on the one hand and the comparatively low surface roughness on the other hand, which can nevertheless be realized with the construction according to the invention.
It can be further appreciated in FIG. 3 that material 68 influencing the permeability of the press belt 32 is provided in some areas in the boundary region between the two support layers 58 , 62 that are constructed with fibrous material. This can be applied, for example, to the surface of the support layer 58 before the application of the support layer 64 or of the support layer 62 , or it can also be introduced into the volume of the support layer 58 . This thus ensures that this material 68 indeed influences the permeability to air, although essentially not the surface structuring in the region of the source material contact surface 42 . This material can comprise silicon material, for example, or also polyurethane material combined with the fibers of the fibrous materials by fusing, which ultimately contributes to a reduction in the exposed volume area for the through-flow of air and is consequently able to lower the air permeability, while also being able to influence the stiffness of the press belt 32 advantageously at the same time. The use of other resin materials, such as acrylic resin materials, or the use of further methods of chemical treatment is also possible here, of course.
In conclusion, it should be pointed out that other possibilities for layering of the support layers and additional or also fewer support layers can, of course, be provided in the construction illustrated in FIG. 3 . This will depend essentially on which structuring it is wished to achieve in the web material to be produced with the machine according to the invention, that is to say, for example, tissue paper. In addition, this will naturally depend fundamentally on which type, which quality, in which weight per unit area and from which available raw materials the web material is intended to be produced.
For the purpose of explaining the second preferred embodiment, it can be appreciated in FIG. 3 , unlike the previously described design, that material 68 influencing the permeability of the press belt 32 is provided in some areas in the boundary region between the two support layers 58 , 62 that are constructed with fibrous material. This can be applied, for example, to the surface of the support layer 58 before the application of the support layer 64 or the support layer 62 , or it can also be introduced into the volume of the support layer 58 . This thus ensures that this material 68 indeed influences the permeability to air, although essentially not the surface structuring in the region of the source material contact surface 42 .
This material can comprise silicon material, for example, or also polyurethane material combined with the fibers of the fibrous material by fusing, which ultimately contributes to a reduction in the exposed volume area for the through-flow of air and is consequently able to lower the air permeability, while also being able to influence the stiffness of the press belt 32 advantageously at the same time. The use of other resin materials, such as acrylic resin materials, or the use of further methods of chemical treatment is also possible here, of course.
It is possible with the construction that can be appreciated in FIG. 3 , for example, to achieve an air permeability of the press belt 32 of less than 1200 cfm or even less than 700 cfm to 800 cfm, preferably even only between approximately 200 cfm to 600 cfm or even only 200 cfm to 400 cfm. This is an air permeability which ensures a sufficiently good dewatering characteristic by the air that is drawn through the press belt 32 and, as a result, also through the source material, although it also provides an additional assurance, on the other hand, that the desired structuring characteristics can be achieved on the source material contact surface 42 .
In conclusion, it should be pointed out that other possibilities for the layering of the support layers and additional or also fewer support layers can, of course, be provided in the construction illustrated in FIG. 3 . This will depend essentially on the structuring that it is wished to achieve with the machine according to the invention in the web material to be produced, for example tissue paper. | A machine for producing fiber-containing web material, in particular tissue paper, includes a permeable dewatering belt for transporting fiber-containing source material used for producing web material from a forming section to a suction/pressing section, and a press belt assembly assigned to the suction/pressing section. The source material is received in the suction/pressing section between the press belt assembly and the dewatering belt and the press belt assembly presses the source material and the dewatering belt against a suction assembly of the suction/pressing section. The press belt assembly has a single press belt providing a source material contact surface. | 3 |
DESCRIPTION
1. Technical Field
This invention relates to a method and apparatus for compressing data to reduce storage and bandwidth requirements.
2. Description of the Prior Art
Compression of data has long been used for two distinct purposes, to reduce the amount of storage space required to hold data on a storage medium and to reduce the number of bits that must be sent over a communications link to transmit the data. One well-known method for compression is to represent the data to be compressed in terms of its differences from some base set of data. For example, [16] applies differencing in a file backup subsystem so that changed versions of a file can be stored in terms of their differences from the original file. Another method [25] is to exploit multiple occurrences of a given pattern within the data to be compressed, replacing each occurrence of such a pattern with a shorter sequence of data acting as a placeholder for the pattern. A special case of this approach is run-length encoding, which entails abbreviating repeated consecutive occurrences of a given bit pattern by a single occurrence of that pattern plus a count of the number of times the pattern is repeated. Various clever schemes, such as that of [20], can be used to reduce the amount of storage occupied by the count. [4] rearranges data to be compressed in a manner that increases the likelihood that adjacent bits will have the same value, thus increasing the average number of times a pattern is repeated and increasing the effectiveness of run-length encoding.
The effectiveness of a compression technique, measured by the factor by which compression reduces the length of the data, depends on the nature of the data to be compressed. Some existing methods are effective when applied to files that are likely to be modified on a line-by-line basis, others are effective when applied to monochromatic fax images, and still others are effective when applied to video images, for example. A method designed for one kind data is not, in general, as effective when applied to other kinds of data. Existing techniques are not designed to be effective for compressing modifications to objects in a distributed object-oriented system. Such an object is typically transmitted in a byte stream containing a serialized representation of the object. Within such a byte stream, changes to a given object are likely to take the form of a few scattered byte sequences, constituting a very small portion of the length of the byte stream, replacing other byte sequences, possibly of a different length.
SUMMARY OF THE INVENTION
An edit sequence is a description of the differences between two sequences of data. Given one of these sequences of data and the edit sequence, it is possible to reconstruct the other sequence of data. The invention represents edit sequences in a compressed form.
The invention represents an edit sequence for two byte sequences in terms of three components: (1) a sequence of bytes inserted by the edit sequence, in order; (2) a bit sequence containing one bit for each byte in the first byte sequence, indicating whether the corresponding byte is deleted by the edit sequence; (3) a bit sequence containing one bit for each byte in the second byte sequence, indicating whether the corresponding byte is inserted by the edit sequence.
Given two similar byte strings, a packed representation of these three components will contain many zero bytes (i.e., bytes all of whose bits are 0). The invention repeatedly applies the following repacking transformation to the representation until the transformation fails to yield a shorter representation: Given a byte string S, a bit sequence is constructed with one bit for each byte of S, having the value 0 if the corresponding byte is zero and having the value 1 otherwise. This sequence of bits is packed and appended to a byte sequence containing all the nonzero bytes of S. The result replaces S.
Both the original three-component representation of the edit sequence and the result of the repacking transformation include an encoding of the number of times repacking has been applied, so that the process can be reversed. Both the original three-component representation of the edit sequence and the result of the repacking transformation include counts giving the lengths of the sequences they contain. These counts are encoded in a manner that tends to concentrate the nonzero bytes near the beginning of the string, thus increasing the likelihood that repacking will result in a shorter string.
This invention is equally applicable when bytes are replaced by other units such as words or half words.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 schematically illustrates the overall environment in which the invention is implemented.
FIG. 2 is a flowchart schematically illustrating the compression of data in accordance with the invention.
FIG. 3 schematically illustrates the level-zero packed representation of an edit sequence.
FIG. 4 schematically illustrates a level-(n+1) packed representation of an edit sequence.
FIG. 5 is a flowchart schematically illustrating the recovery of an original sequence from its compressed representation.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A sequence of values is data, such as a string of bytes in a computer memory, that may represent some computational entity such as a Java object. Referring to FIG. 1, this invention constructs a succinct representation, Δ x ,b, for the differences between a sequence of values x and a base sequence of values b. These differences can be applied to b to restore x.
A collection of data with many elements similar to b can be compressed by replacing x with Δ x ,b.
Given a low-bandwidth or high-cost communications link with a copy of b present at each side of the link, the effect of transmitting x across the link can be achieved by computing Δ x ,b on the transmitting side 10 of the link, transmitting Δ x ,b 15 across the link, and reconstructing x from Δ x ,b and b on the receiving side 20 of the link.
In a typical application, there will be many candidate sequences of values present on both sides of the link that can serve as the base sequence b. Then, along with Δ x ,b, we must transmit a short key 17 (such as an array subscript) indicating which candidate is to be used as the base.
For example, in a distributed database system, the collections of candidate base sequences 25 could consist of items already in the database and known to be cached by the receiver. The invention produces more succinct representations of Δ x ,b when there are fewer differences between x and b. Thus a system incorporating the invention should choose a base sequence close to x. For example, if an item x in a distributed database system results from making small changes to some other item b already in the database and known to be present at the other nodes of the distributed system, it makes sense to use b as the base for transmitting x to the other nodes.
In an object-oriented distributed system, x could be a serialized representation of an object to be transmitted, e.g., in a remote procedure call, to another node. The collection of candidate base sequences 25 could be a set of serialized representations of base objects, such that x is likely to be a small mutation of one of the base objects. (Instead of storing such serialized representations in a large table, such a system could maintain mirrored caches of objects at the sending and receiving nodes, use the key 17 to retrieve objects, and compute serialized representations from retrieved objects on demand.)
Algorithm for Constructing Δ x ,b
Shown in FIG. 2 is a flowchart summarizing the algorithm used for generating Δ x ,b from x and b. The terms minimal-length edit sequence, level-0 packed representation, and repack used in the flowchart are explained below.
Minimal-Length Edit Sequences and Longest Common Subsequences
Given two sequences of values b and x, a minimal-length edit sequence transforming b into x is the shortest possible sequence of deletions of values from specified positions and insertions of specified values at specified positions that, when applied to b, will yield x. For example, if we view the strings "REDMOND" and "ARMONK" as sequences of character values, a minimal-length edit sequence transforming the first string into the second consists of five operations: deleting the characters `E`, `D`, and `D`, inserting the `A` before the `R`, and inserting the `K` after the `N`.
The problem of computing the minimal-length edit sequence between two sequences of values is equivalent to the problem of finding a longest common subsequence (LCS) shared by those sequences of values. A subsequence of a sequence of values s is another sequence of values, all of whose elements occur, perhaps with other values interleaved, in the same order in s. A longest common subsequence of two sequences x and y is a a maximal-length sequence of values that is a subsequence of both x and y. For example, subsequences of "ARMONK" include "A", "AMN", "ROK", and "AK", among others; subsequences of "REDMOND" include "R", "RDOD", and "EDD", among others. The longest sequence of character values that is common to "ARMONK" and "REDMOND" is "RMON". Given a common subsequence between sequences x and y, one can construct an edit sequence transforming x into y by deleting values in x that are not part of the common subsequence and inserting, at the appropriate places, values in y that are not part of the common subsequence.
Every edit sequence transforming x into y can be characterized in this way. The more values there are in the common subsequence, the fewer insertions and deletions there are in the resulting edit sequence. Thus a longest common subsequence corresponds to a minimal-length edit sequence.
There are many algorithms known for computing minimal-length edit sequences (or, equivalently, longest common subsequences). Such algorithms are presented in [1], [2], [3], [5], [6], [7], [8], [9], [10], [11], [13], [15], [17], [18], [19], [21], [22], [23], and [24]. Our embodiment uses (see 21 of FIG. 2) the Miller-Myers algorithm [15] (independently discovered by Ukkonen [22]) because of its simplicity and relative efficiency. Reference [15] is hereby incorporated herein by reference. This is also the algorithm used in the GNU diff program [12] and in the electrocardiogram data compression system described in [14]. Different algorithms to compute minimal edit sequences differ in the amount of time and space needed to perform the computation, but not, of course, in the length of the resulting edit sequence (which is, by definition, minimal).
The Level-0 Packed Representation of an Edit Sequence
An edit sequence can be characterized by three pieces of data:
the set of positions in the original sequence from which values are deleted
the set of positions in the resulting sequence at which values are inserted
an ordered list of the values that have been inserted at the latter positions
This data is sufficient to apply the edit sequence to the original sequence of values. (In particular, the actual values deleted from the original sequence are not needed.)
The level-0 packed representation of the edit sequence is a representation of these three pieces of data. See 22 of FIG. 2. In our embodiment, our sequences of values are sequences of 8-bit bytes and, referring to FIG. 3, the level-0 packed representation 100 is a sequence of 8-bit bytes consisting of the following:
A descriptor byte 102 whose six high order bits are a level number 102A and whose two low-order bits 102B indicate the number of bytes needed to hold the number of insertions. (That is, the two low-order bits indicate the length of the insertion count itself) The level number for a level-0 packed representation is always zero. If the number of insertions is less than 2 8 , the insertion count 104 is one byte long, and the corresponding bits 102B of the descriptor byte have the values 00. Otherwise, if the number of insertions is less than 2 16 , the insertion count 104 is two bytes long, and the corresponding bits 102B of the descriptor byte have the values 01. Otherwise, if the number of insertions is less than 2 24 , the insertion count 104 is three bytes long, and the corresponding bits 102B of the descriptor byte have the values 10. Otherwise, if the number of insertions is less than 2 32 , the insertion count 104 is four bytes long, and the corresponding bits 102B of the descriptor byte have the values 11. The embodiment can only encode edit sequences with fewer than 2 32 insertions; however, it would be straightforward to allow for a number of insertions exceeding 2 32 .
The insertion count 104, i.e., the number of bytes of insertions: The length of the insertion count is as indicated by lower order two bits 102B of the descriptor byte. Lower-order bytes of the insertion count occur earlier (i.e., the insertion count is given in "little-endian" form).
The sequence of byte values 106 inserted by the edit sequence: The number of bytes in this sequence is given by the insertion count 104. Bytes in this sequence occur in the same order as in the byte sequence that results from applying the edit sequence.
The interleaved lengths 108 of the insertion mask and the deletion mask (each described below): The insertion-mask length 111 and the deletion-mask length 113 are 4-byte integers, each indicating the number of bits in the corresponding mask. If we designate the four bytes of the insertion-mask length 111, going from least significant to most significant, as 10, 11, 12, and 13, and the four bytes of the deletion-mask length 113, going from least significant to most significant, as D0, D1, D2, and D3, then their interleaved lengths consist of the bytes I0, D0, I1, D1, I2, D2, I3, D3, in that order. See 108 of FIG. 3.
The insertion mask 110: The insertion mask contains one bit for each byte of the byte sequence that results from applying the edit sequence. A 0 bit indicates that the corresponding byte of the edit-sequence result was part of the original byte sequence; a 1 bit indicates that the corresponding byte of the edit-sequence result was inserted by the edit sequence. An insertion mask with b bits is represented in ceiling(b/8) bytes (i.e., the smallest whole number of bytes greater than or equal to b/8), with earlier bytes of the representation, and higher-order bits within a given byte, holding earlier bits of the insertion mask. The last byte of the insertion mask may contain up to 7 padding bits following the last bit of the mask.
The deletion mask 112. The deletion mask contains one bit for each byte of the original byte sequence to which the edit sequence is applied. A 1 bit indicates that the corresponding byte of the original byte sequence is deleted by the edit sequence; a 0 bit indicates that it is not deleted. A deletion mask with b bits is represented in ceiling(b/8) bytes, with earlier bytes of the representation, and higher-order bits within a given byte, holding earlier bits of the deletion mask. The last byte of the deletion mask may contain up to 7 padding bits following the last bit of the mask.
Referring to FIG. 2, repacking 26 is the process of converting a level-n packed representation into a level-(n+1) packed representation (See 200 of FIG. 4.), where n is some value from 0 to a specified maximum (63 in our embodiment), inclusive. The level-(n+1) packed representation is a compressed form of the level-n packed representation. In our embodiment, the level-(n+1) packed representation is a sequence of 8-bit bytes consisting of the following:
Referring to FIG. 4, a descriptor byte 202 whose six high order bits 202A are a level number and whose two low-order bits 202B indicate the number of bytes needed to hold the level-n length 204, which length is the number of bytes in the level-n packed representation. The level number for a level-(n+1) packed representation is n+1. If the number of bytes in the level-n packed representation is less than 2 8 , the level-n byte count 204 is one byte long, and the corresponding bits 202B of the descriptor byte 202 have the values 00. Otherwise, if the number of bytes in the level-n packed representation is less than 2 16 , the level-n byte count 204 is two bytes long, and the corresponding bits 202B of the descriptor byte have the values 01. Otherwise, if the number of bytes in the level-n packed representation is less than 2 24 , the level-n byte count 204 is three bytes long, and the corresponding bits 202B of the descriptor byte have the values 10. Otherwise, the level-n byte count 204 is four bytes long, and the corresponding bits 202B of the descriptor byte have the values 11.
The level-n byte count 204, i.e., the number of bytes in the level-n packed representation. The length of the level-n byte count is as indicated by the two low-order bits 202B of the descriptor byte. Lower-order bytes of the count occur earlier (i.e., the count is given in "little-endian" form).
The nonzero bytes 206 of the level-n packed representation, occurring in the same order as in the level-n packed representation.
A zero byte, 208, marking the end of the nonzero bytes.
A mask 210 containing one bit for each byte of the level-n packed representation, with a 0 bit indicating that the corresponding byte of the level-n packed representation has the value 0 and a 1 bit indicating that the corresponding byte of the level-n packed representation has one of the values 1 through 255. A mask with m bits is represented in ceiling(m/8) bytes (i.e., the smallest whole number of bytes greater than or equal to m/8), with earlier bytes of the representation, and higher-order bits within a given byte, holding earlier bits of the mask. The last byte of the mask may contain up to 7 padding bits following the last bit of the mask.
Algorithm for Reconstructing x from Δ x ,b and b
Referring to FIG. 5, let variable r represent a level-n packed packet representation of Δ x ,b for some integer n≧0. See 51.
The level of a packed representation r can be determined 52 by examining the high-order 6 bits of the descriptor byte, which is the first byte of r.
A level-(n+1) packed representation can be unpacked 53 into a level-n packed representation as follows, referring to FIG. 4:
1. Examine the two low-order bits 202B of the descriptor byte 202 to determine the length, L, of the level-n byte count 204.
2. Extract the level-n byte count, c, from the next L bytes 204 of r and create an array of c bytes.
3. Establish an index into the sequence 206 of nonzero bytes from the level-n representation 200, which sequence starts after the last byte of the level-n byte count 204. Initially, the index refers to the beginning of the sequence.
4. Scan for the zero byte 208 at the end of the sequence of nonzero bytes 202 and establish an index into the mask 210, which starts after the zero byte 208.
5. Fill in each element of the byte array according to the corresponding bit of the mask 210. If the mask bit is 1, the value to be placed in the byte-array element is taken from the currently indexed position in the sequence of nonzero bytes 206, and the index is advanced. If the mask bit is 0, the value 0 is placed in the byte-array element.
Referring to FIG. 3, a level-0 packed representation (100) r of Δ x ,b can be used to edit b, obtaining x (See 54 of FIG. 5), as follows:
1. Examine the two low-order bits 102B of the descriptor byte 102 to determine the length, L, of the insertion count.
2. Extract the insertion count, c, from the next L bytes 104 of r.
3. Establish an index i into the sequence 106 of inserted byte values, which starts after the last byte of the insertion count 104. Initially, the index refers to the beginning of the sequence.
4. Find the interleaved lengths 108 of the insertion and deletion masks starting c bytes after the first inserted byte value and reconstruct the insertion-mask length LI (111) and the deletion-mask length LD (113). (Note that LI is the required length for x and LD is the length of b.)
5. Establish an index j into the insertion mask 110, which begins c+8 bytes after the first inserted byte value.
6. Establish an index k that will identify elements of b as well as the corresponding elements of the deletion mask 112, which begins LI bytes after the beginning of the insertion mask.
7. Create an array of LD bytes that will hold x.
8. Fill in each element of x according to the corresponding bit of the insertion mask 110. If the insertion-mask bit is 1, the value to be placed in the element of x is taken from the position in the sequence 106 of inserted byte values currently indexed by i, and the index i is advanced. If the insertion-mask bit is 0, advance the index k as many times as necessary (possibly 0) until k indexes a zero bit in the deletion mask, then copy the byte of b currently indexed by k into x. In either case, advance the index j to index the next element of the insertion mask 110 and the next element of x.
References
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18. Nakatsu, N., Kambayashi, Y., and Yajima, S. A longest common subsequence algorithm suitable for similar text strings. Acta Informatica 18 (1982), 171-179.
19. Rick, Claus. A new flexible algorithm for the longest common subsequence problem. Nordic Journal of Computing 2 (1995), 444-461.
20. Takahara, Toru, "Encoder in Facsimile Apparatus Generates Code Words with One Bit Address Indicating Remaining Bits Are Raw Unencoded Data When Number of Pixels in a Run Length Are Below a Predetermined number," U.S. Pat. No. 5,493,407, Feb. 20, 1996.
21. Tichy, W. The string-to-string correction problem with block moves. ACM Transactions on Computing Systems 2 (1984), 309-321.
22. Ukkonen, Esko. Algorithms for approximate string matching. Information and Control 64 (1985), 100-118.
23. Wagner, R. A., and Fischer, M. J. The string-to-string correction problem. Journal of the ACM 21, No. 1 (January 1974), 168-173.
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25. Ziv, J., and Lempel, A. "Compression of Individual Sequences Via Variable Rate Encoding," IEEE Transactions on Information Theory IT-24, No. 5, 1978, pp. 530-536. | A method of compressing data, including representations of objects, for future transmission or storage. More specifically, this invention compresses a representation of differences between a base sequence of data and the actual data to be transmitted or stored. Sparse bit masks representing the positions of insertions and deletions from a base sequence are iteratively compressed by representing consecutive sequences of zero-valued bits with single zero-valued bits. | 7 |
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of co-pending International Application No. PCT/EP2004/003717 filed Apr. 7, 2004 which designates the United States of America, and claims priority to German Application No. 103 22 853.5 filed May 21, 2003, the contents of which are hereby incorporated by reference in their entirety.
TECHNICAL FIELD
The invention concerns a key system for a vehicle with transmitting electronics arranged in housing for contactless locking and/or unlocking of a door of a vehicle and/or operation of a vehicle, and with an emergency key for mechanical locking and/or unlocking of the door of the vehicle and/or for operation of the vehicle.
BACKGROUND
The task of the invention is to improve such a key system.
The aforementioned task is solved by a key system for a vehicle with transmitting electronics arranged in a housing for contactless locking and/or unlocking of a door of a vehicle and/or for operation of a vehicle, as well as an emergency key for mechanical locking and/or unlocking of the door of the vehicle and/or operation of the vehicle, in which the emergency key can be accommodated (essentially) fully in the housing (and advantageously locked into this position).
A vehicle according to the invention is especially a ground vehicle, usable individually in traffic. The vehicles according to the invention are not particularly restricted to ground vehicles with an internal combustion engine. A door (of a vehicle) according to the invention can be a door, front or rear hatch or trunk. An emergency key designed for mechanical operation of the vehicle according to the invention corresponds, in particular, to a mechanical ignition key.
For essentially full accommodation of the emergency key in the housing of the key system, the emergency key, in an advantageous embodiment of the invention, can be accommodated essentially fully in one edge of the housing.
In another advantageous embodiment of the invention, the emergency key and the housing are fully separable from each other. That the emergency key and the housing are fully separable from each other according to the invention means especially that the emergency key and the housing can be fully separated from each other without destruction and without a tool. This means, in particular, that the emergency key and the housing can be fully separated from each other for use of the emergency key without difficulty.
In another advantageous embodiment of the invention, the emergency key is designed to be mounted on a key ring.
In another advantageous embodiment of the invention, the emergency key has a closure element for mechanical locking and/or unlocking of the door of the vehicle and/or for operation of the vehicle and a receiving element appropriate to receive a key ring. The closing element and the receiving element in another advantageous embodiment of the invention are then movably connected to each other, advantageously by means of a link, especially by means of a hinge.
In another advantageous embodiment of the invention, the closure element or emergency key has a closure piece for mechanical locking and/or unlocking of the door of the vehicle and/or for operation of the vehicle and an insertion element, into which the closure piece can be inserted.
In another advantageous embodiment of the invention, the emergency key, has a receiving element appropriate to receive a key ring.
In another advantageous embodiment of the invention, the insertion element and the receiving element are movably connected to each other, advantageously by means of a link, especially a hinge.
In another advantageous embodiment of the invention, the emergency key can be locked in a first locking position and in a second locking position different from the first locking position in the housing.
The emergency key, in another advantageous embodiment of the invention in the first locking position, is essentially fully in the housing and advantageously in the second locking position (especially only in this position), is accommodated in the housing to the extent that the receiving element for a key ring (for the purpose of threading) can be reached.
In another advantageous embodiment of the invention, the emergency key in the second locking position (especially only in this position) is accommodated in the housing to the extent that the receiving element can be pivoted.
In another advantageous embodiment of the invention, the emergency key in the second locking position (especially only in this position) is accommodated in the housing, so that (only) the closure element is essentially accommodated in the housing.
In another advantageous embodiment of the invention, the emergency key can be pushed into the housing when the second locking position is released.
In another advantageous embodiment of the invention, the emergency key is separable from the housing, when released in the second locking position.
In another advantageous embodiment of the invention, the key system has a pushbutton to release the second locking position.
It can be prescribed that the housing have a receiving element appropriate to accommodate a key ring. The receiving element can be connected movably to the housing and, at least in one closure position, in which the receiving element forms a closed unit with the housing, and can be arranged in a threading position, in which a key ring can be threaded onto the receiving element.
The aforementioned task is additionally solved by a key system for a vehicle with transmitting electronics arranged in the housing for contactless locking and/or unlocking of a door of the vehicle and/or for operation of the vehicle, in which the housing has a receiving element suitable for receiving a key ring, which is movably connected to the housing and can be arranged, at least one closure position, in which the receiving element forms a closed unit with the housing, and in a threading position, in which a key ring can be threaded onto the receiving element.
In advantageous embodiment of the invention, the key system has an emergency key for mechanical locking and/or unlocking of the door of the vehicle and/or operation of the vehicle, in which the emergency key can be accommodated, at least partially, preferably essentially fully, in the housing.
BRIEF DESCRIPTION OF THE DRAWINGS
Additional advantages and details are apparent from the following description of practical examples. In them:
FIG. 1 shows a practical example of a key system in a first locking position.
FIG. 2 shows the practical example of the key system according to FIG. 1 in a second locking position.
FIG. 3 shows the practical example of the key system according to FIG. 1 with an emergency key separated from the housing.
FIG. 4 shows the practical example of the key system according to FIG. 1 in a first locking position in a three-dimensional view.
FIG. 5 shows the practical example of the key system according to FIG. 1 in a second locking position in a three-dimensional view.
FIG. 6 shows the practical example of the key system according to FIG. 1 in a second locking position in a three-dimensional view.
FIG. 7 shows a practical example of an emergency key.
FIG. 8 shows another practical example of a key system.
FIG. 9 shows a practical example of the key system according to FIG. 8 with a key ring.
FIG. 10 shows the practical example of a key system according to FIG. 8 in a three-dimensional view.
FIG. 11 shows the practical example of a key system according to FIG. 9 in a three-dimensional view.
FIG. 12 shows another practical example of a key system.
FIG. 13 shows the practical example of the key system according to FIG. 12 in an opened state.
FIG. 14 shows the practical example of the key system according to FIG. 12 with a threaded key ring.
FIG. 15 shows the practical example of the key system according to FIG. 12 in a three-dimensional view.
FIG. 16 shows the practical example of the key system according to FIG. 13 in a three-dimensional view.
FIG. 17 shows the practical example of the key system according to FIG. 14 in a three-dimensional view.
FIG. 18 shows another practical example of the key system in a three-dimensional view.
FIG. 19 shows the practical example of the key system according to FIG. 18 in an open state.
FIG. 20 shows the practical example of the key system according to FIG. 18 in a closed state with a threaded key ring.
FIG. 21 shows another practical example of the key system.
FIG. 22 shows the practical example of the key system according to FIG. 21 in an opened state in a three-dimensional view.
FIG. 23 shows the practical example of the key system according to FIG. 21 in an opened state.
FIG. 24 shows the practical example of the key system according to FIG. 21 in a closed state with a threaded key ring.
FIG. 25 shows the practical example of the key system according to FIG. 21 in a half-opened state.
DETAILED DESCRIPTION
FIG. 1 shows a practical example for a key system 1 situated in a first locking position for a vehicle, with transmitting electronics arranged in a housing 2 for contactless locking and/or unlocking of the door of a vehicle and/or for operation of the vehicle, and with an emergency key 3 for mechanical locking and/or unlocking of the door of the vehicle and/or operation of the vehicle. The emergency key 3 is fully accommodated in the upper edge 4 of housing 2 . The emergency key 3 has an opening 5 , into which, as shown in FIG. 5 and FIG. 6 , a key ring 10 can be threaded.
The emergency key 3 , as shown in FIG. 2 , can be partly pushed out from housing 2 into a second locking position. In this second locking position, the opening 5 , as shown in FIG. 5 and FIG. 6 , a key ring 10 can be threaded. In addition, the emergency key in the second locking position releases a pushbutton 6 . By pressing pushbutton 6 , a locking mechanism in the housing 2 is released, so that housing 2 and the emergency key are separable and can form two separate objects, as shown in FIG. 3 .
FIG. 4 , FIG. 5 , and FIG. 6 show the key system 1 in a three-dimensional view. The key system 1 in FIG. 4 is shown in its first locking position. Arrow 7 shows that the emergency key 3 can be pushed (partially) from housing 2 into a second locking position. FIG. 5 and FIG. 6 show the key system in its second locking position, in which a key ring 10 is threaded through opening 5 .
FIG. 7 shows the emergency key 3 in a three-dimensional view. The emergency key 3 has a closing element 20 with a closing piece 22 for mechanical locking and/or unlocking of the door of the vehicle and/or for operation of the vehicle and with an insertion element 23 , into which the closure element 22 , as indicated by the double arrow 25 , can be pushed in and out. The insertion element 23 is connected to tilt via a hinge 24 to a receiving element 21 . In this way, the hazard of injury during an accident can be reduced. The receiving element 21 in FIG. 6 of the emergency key pushed into the second locking position in the housing 2 is tilted back. An opening 5 is arranged in the receiving element 21 .
FIG. 8 shows another practical example of a key system 30 for a vehicle, FIG. 9 shows the practical example of the key system 30 according to FIG. 8 with a key ring 33 , FIG. 10 shows the practical example of the key system 30 according to FIG. 8 in a three dimensional view and FIG. 11 shows the practical example of the key system 30 according to FIG. 9 in a three-dimensional view. The key system 30 has transmitting electronics arranged in a housing 31 for contactless locking and/or unlocking of the door of the vehicle and/or for operation of the vehicle, as well as a loop-like receiving element 32 , appropriate to accommodate a key ring 33 , which is connected movably to housing 31 .
In the position depicted in FIG. 8 and FIG. 10 , the loop-like receiving element 32 is flush with the surface of housing 31 , so that it does not protrude beyond the basic outline of housing 31 . The loop-like receiving element 32 , as shown in FIG. 9 and FIG. 11 , can be tilted back, so that the key ring 33 can be threaded into the receiving element.
Another practical example of a key system 40 is shown in FIG. 12 , FIG. 13 shows the practical example of the key system 40 according to FIG. 12 in an opened state, FIG. 14 shows the practical example of the key system 40 according to FIG. 12 with a threaded key ring 45 , FIG. 15 shows the practical system of the key system 40 according to FIG. 12 in a three-dimensional view, FIG. 16 shows the practical example of the key system 40 according to FIG. 3 in a three-dimensional view, but without the key ring 45 , for reasons of clarity, and FIG. 17 shows the practical example of the key system 40 according to FIG. 14 in a three-dimensional view. The key system 40 has transmitting electronics arranged in a housing 41 for contactless locking and/or unlocking of a door of the vehicle and/or for operation of the vehicle, as well as receiving element 42 , suitable for receiving key ring 45 , which is movably connected to housing 41 .
In the position depicted in FIG. 12 and FIG. 15 , the receiving element 42 covers a face of housing 41 flush. The housing has a pushbutton 43 . If the pushbutton 43 is pressed, the receiving element 42 is moved in the direction of arrow 44 into a position depicted in FIG. 13 and FIG. 16 . The receiving element 42 has a long retaining pin 48 , which, in the position depicted in FIG. 13 and FIG. 16 , connects the receiving element 42 to housing 41 , and a short retaining pin 49 . In this position, the key ring 45 , as shown in FIG. 13 , can be threaded between housing 41 and the short retaining pin 49 .
After threading of key ring 45 , the receiving element 42 can be moved in the direction of arrow 46 on housing 41 , so that both the long retaining pin 48 and the short retaining pin 49 connect the receiving element 42 to housing 41 and the key ring 45 is enclosed.
FIG. 18 shows another practical example of a key system 50 in a three-dimensional view. The key system 50 has transmitting electronics arranged in a housing for contactless locking and/or unlocking of the door of a vehicle and/or for operation of the vehicle, as well as a receiving element 52 , suitable for accommodating a key ring 56 with an opening 54 . The receiving element 52 is connected by means of a pin 53 to housing 51 , pivotable in the direction of arrow 57 .
FIG. 19 shows the key system 50 in an opened state, i.e., after pivoting of he receiving element 52 . In this state, the key ring 56 can be threaded into opening 54 . After threading of the key ring 56 , the receiving element 52 can be pivoted back, in which case a recess 55 is provided for the key ring 56 on housing 51 . FIG. 20 shows the key system 50 in this newly closed state with the threaded key ring 56 .
FIG. 21 shows another practical example of a key system 60 . The key system 60 has transmitting electronics arranged in a housing 61 for contactless locking and/or unlocking of a door of a vehicle and/or for operation of a vehicle, and a receiving element 62 , removable from housing 61 , suitable for accommodating a key ring 65 . FIG. 22 shows the key system 60 in a three-dimensional view, in which the receiving element 62 is separated from housing 61 . The receiving element 62 has an opening 63 , through which the key ring 65 is threaded.
The housing 61 has a recess 64 , into which the receiving element 62 can be snapped when it is pushed, as shown in FIG. 23 , in the direction of arrow 66 , onto housing 61 . FIG. 24 shows the key system 60 in a closed state, i.e., after the receiving element 62 has been pushed onto housing 61 , with the threaded-on key ring 65 .
FIG. 25 shows the key system 60 in a half-opened state. By pushing the receiving element 62 relative to housing 61 in the direction of arrow 67 , the receiving element 62 can be separated from housing 61 .
The key systems 30 , 40 , 50 and 60 each have an emergency key (not shown) for mechanical locking and/or unlocking of the door of a vehicle and/or operation of a vehicle, in which the emergency key can be accommodated, at least partly and advantageously essentially fully, in housing 31 , 41 , 51 or 61 .
Especially in connection with the key systems 30 , 40 , 50 and 60 , it can be prescribed to design the housings 31 , 41 , 51 and 61 at least in two parts, i.e., from at least two parts, in which the two parts of housing 31 , 41 , 51 or 61 permit opening of housing 31 , 41 , 51 or 61 by tilting a part of the opening or are completely separable from each other. The fact that the two parts of housing 31 , 41 , 51 and 61 are fully separable from each other means, according to the invention, in particular, that the two parts of housing 31 , 41 , 51 and 61 can be separated from each other fully, free of destruction and without a tool. This means that the two parts of housing 31 , 41 , 51 and 61 are fully separable from each other for a user of the key without difficulty. If the housing 31 , 41 , 51 or 61 is opened, an emergency key can be removed. | A key system ( 1 ) for a motor vehicle comprises transmitter electronics arranged inside a housing ( 2 ) and used for the contactless locking and/or unlocking of a door of the motor vehicle and/or operation of the motor vehicle. The system further comprises an emergency key ( 3 ) for mechanically locking and/or unlocking the door of the motor vehicle and/or for the operation of the motor vehicle. The emergency key is received inside the housing ( 2 ) in a substantially complete manner. | 4 |
This application claims priority to U.S. provisional patent application No. 61/684,529, filed 17 Aug. 2012, the complete disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTION
The invention relates to a system and method for cutting boards into two board pieces, even ending one of the board pieces at a first side while travelling transversely on a conveyor and even ending the other board piece at a second side of the conveyor.
BACKGROUND OF THE INVENTION
It is common for lumber to be cut into two pieces transversely, i.e. 2×4×20′ cut into 2−2×4×10′, to improve the overall grade and therefore value. An example is a board that has knots or other defects in one end, but not the other end. Cutting into two shorter boards keeps the defects in one segment from devaluing the other segment.
Typically, lumber cut in this manner in automated lumber handling systems require one part to be diverted to another system or one of the two boards to be relocated to an empty lug for handing. A common method to relocate is for the control system to recognize the need and to interrupt the feeding process to allow an empty lug to be developed right behind the lug containing the board needing to be relocated and arms used to lift one portion over the lugs and into the empty lug space. The creation of the empty lug amounts to loss of opportunity and the related lost production. There have been methods devised in an attempt to solve this problem, that require each board to be acted upon individually, causing complexity in controls and mechanical systems, limiting the speed possible and increasing the cost.
An example of prior art cutting systems shown in U.S. Pat. No. 6,892,614 (Olsen), issued, 17 May 2005, and U.S. Published Patent Application No. 2003/0183052 (Olsen), published 2 Oct. 2003, the complete disclosures of which are incorporated herein by reference.
SUMMARY OF THE INVENTION
An objective of the invention is to provide an efficient system and method in which the two portions of the cut in two board remains on their original now shared lug space, but each piece is even ended so that they can be sorted or other manufacturing process performed independently. Due to length variation of the boards, it is required that the boards be even ended to an index point to allow automated handing and processing.
Provided is a double even ending board cutting system comprising:
a conveyor comprising an endless chain loop having lugs constructed to convey un-cut boards and boards cut into first and second board pieces transversely, the first conveyor having a first side index line and a second side index line; a first section of the conveyor comprising a plurality of first powered rollers constructed to move first board pieces travelling on the conveyor to the first side index line to even end first board pieces at the first side index line traveling through the first section; a second section of the conveyor comprising a plurality of second powered rollers constructed to move second board pieces travelling on the conveyor to the second side index line to even end second board pieces at the second side index; and an overhead hold back constructed to hold the second board pieces in place on the traveling conveyor while the first board pieces are being moved by the first powered rollers and to hold the first board pieces in place while the second board pieces are being moved by the second powered rollers.
Also provided is a method of double even ending boards comprising:
conveying a first board piece and a second board piece transversely on a conveyor comprising an endless chain loop having lugs, the first conveyor having a first side index line and a second side index line; using a plurality of first powered rollers located in a first section of the conveyor to move the first board piece to the first side index line to even end the first board piece, using an overhead hold back to hold the second board piece and any uncut boards in place while the first board piece is being moved; and using a plurality of second powered rollers located in a second section of the conveyor to move the second board piece to the second side index line to even end the second board piece, using the overhead hold back to hold the first board piece in place while the second board piece and any uncut boards are being moved.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a side view of section A of the system.
FIG. 2 illustrates a side view of section B of the system.
FIG. 3 illustrates a side view of section C of the system.
FIG. 4 illustrates a top view of the system.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The system and method to even end each end of a cut in two board to opposite even ends of the system without needing electronic controls or complicated mechanical systems will be described with reference to the attached non-limiting Figures.
The system comprises a conveyor 2 having a plurality of lugged chains 4 with lugs 6 attached driven in such a way as to convey boards 20 transversely. The system further comprises a cutter 8 constructed to cut the boards 20 into first board pieces 22 and second board pieces 24 . The conveyer 2 has a first index line 30 on a first side, such as a far side, and a second index line 34 on a second side, such as a near side.
A first section B, shown in FIG. 2 , of the conveyor comprises a series of first powered rollers 32 to propel the first board piece 22 to the first index 30 while the piece 22 is traveling on the chains 4 over the rollers 32 . These rollers 32 are directed to even end the first board pieces 22 to the first side index line 30 . An overhead hold back device 40 is constructed to hold the second board pieces 24 and uncut boards 20 in place on the chains 4 (i.e. the second board pieces 24 and uncut boards 20 continue to travel with the chains 4 but are not moved in relation to the sides of the conveyor 2 ) while the first board pieces 22 are even ended at the first index line 30 by the first rollers 32 .
The hold back device 40 employs, for example, a rigid support member 42 running in the direct of lumber flow with a flexible portion 44 attached. This flexible portion 44 is angled to and in contact with the second board pieces 24 and uncut boards 20 to prevent them from moving in the direction to the far end index line 30 but allowing them to be propelled by the chains 4 in the chain flow direction. This flexible member 44 can be as long as the rollers 32 and in contact with a multiple of boards 24 and 20 of varying sizes effectively preventing them from changing their location in a side-to-side direction. Exiting this first section B far end cut in two boards 22 have been positioned to the first index line 30 and all others (un cut boards 20 and near end cut in two boards 24 ) have not moved from their original location relative to the sides of the conveyor 2 .
It is envisioned that the system can work without the flexible member 44 being angled. Also, an opposing member underneath the lumber powered or unpowered may be used to improve the performance of the hold back device 40 .
A second section C, shown in FIG. 3 , of the conveyor 2 is much like the first section B, with a plurality of second rollers 36 operating in the opposite direction as the first rollers 32 , i.e. toward the second index line 34 . In the second section C, the second board pieces 24 and uncut boards 20 are moved by the second rollers 36 towards the second index line 34 to even end the second board pieces 24 at the second index line 34 . The overhead hold back device 40 is constructed to hold the first board pieces 22 in place on the chains 4 while the second board pieces 24 and uncut board pieces 20 are even ended at the second index line 34 by the second rollers 36 .
In this embodiment, the rollers 32 and 36 remain running as long as the chain 4 is running, thus not requiring a control system. However, a control system can be used if desired to control the rollers 32 and 36 and chain 4 .
While the invention has been described with reference to particular embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the scope of the invention. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope and spirit of the appended claims. | Provided are a system and method for cutting boards into two board pieces, even ending one of the board pieces at a first side while travelling transversely on a conveyor and even ending the other board piece at a second side of the conveyor. | 1 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a system and method for the cathodic protection of structures such as pipelines and well casings disposed in an electrically conducting medium such as the ground and more particularly to such a system utilizing pulsed D.C. current to protect a plurality of such structures in which the spacing between the structures and/or different electrical properties of the conducting medium surrounding the structures are not amenable to the use of a single pulsed source.
2. Description of the Prior Art
The use of cathodic protection to prevent corrosion is well established for the protection of metal structures, such as well casings and pipe lines, that are buried in conductive soils. Cathodic protection is also used for the protection of inner surfaces of tanks which contain corrosive solutions, as well as for the protection of sub-platforms, and other off-shore metal structures. It is well established that the cathodic protection can be accomplished either by the use of sacrificial anodes electrically grounded to the structure to be protected, or by the application of low voltage direct current from a power source. In the latter method steady direct current, half or full wave rectified current, and pulsed direct current have all been used.
It has been well established that, when a cathodic protection current is applied to a circuit including the structure (cathode) to be protected and its associated anode, a layer of charge is formed at approximately 100 A. from the surface of the structure. This layer of charge is called a taffel double layer. This layer acts as a capacitor in series with the anode-cathode circuit. In the absence of a cathodic protection system the soil or other conductive corrosive medium to which a ferrous metal structure such as a steel pipeline is exposed will cause an adverse chemical reaction in which ferrous or iron molecules pass into solution as positive ions by surrendering electrons to the structure. Hydrogen ions in the solution will accept the free electrons and form a gas, e.g. H 2 , adjacent to the surface of the structure. Oxygen molecules and certain other substances, if present in the solution, will also accept the electrons. This action results in a loss of iron in the structure with a consequent degradation of structural integrity.
Direct current cathodic protection systems prevent (or inhibit) the iron molecules from passing into solution by providing an exterior source of free electrons to the structure. The electrons supplied by the cathodic protection systems reduce any oxygen molecules and/or hydrogen ions present at the surface of the structure. The iron molecules are inhibited from going into solution, because the hydrogen ion and oxygen molecule receptors for the iron molecule electrons have been reduced by the cathodic protection system electrons. As a general rule, the greater the amount of current (accumulated electrons per unit of time) that is supplied by the cathodic protection system, the greater will be the area of structure protected.
A typical steady state 15 volt and 15 ampere D.C. cathodic protection system offers good protection but provides only a limited umbrella of protection or throw along the structure such as a pipeline to be protected. Such steady state systems thus require a considerable number of protection stations for a given length of the structure or pipe to be protected. Increasing the amount of current supplied by increasing the voltage, will increase the throw. The average current must, however, be limited such that an excess of hydrogen gas is not generated at the point of application of the cathodic protection system. An excess of hydrogen may cause damage to protective coatings. Excess hydrogen will also permeate the pipe wall, causing certain pipe materials to crack or rupture.
It has been shown that a pulsed D.C. voltage source having an output of the order of 100-300 volts for 5-100 microseconds (“μs”) with a duty cycle of the order of 10% provides a much greater coverage (or throw) per station e.g. one station every few miles of pipeline. Such pulsed systems have been considered to be particularly effective because, although the average current is still in the order of magnitude of 15 amperes, the peak current, which is flowing for a sufficient length of time to cause the protective reactions to take place, will be typically as high as 300 amperes. The pulsed D.C. systems also cause a greater redistribution of the current along the structure, such as a pipeline, because of the inductive and capacitive reactance of the anode and structure system.
Copper-copper sulfate electrodes are conventionally used to determine the effectiveness of cathodic protection systems in protecting well casings and pipelines. Such electrodes, comprising a copper rod immersed in a copper sulfate solution (typically a gel) are placed in the ground, adjacent the well casings or pipeline (e.g., 1 or 2 feet there from) and the potential between the metal structure and the copper rod is measured. A potential, typically called “the well head potential”, of about 1 volt is considered to provide appropriate protection.
Prior art cathodic protection systems are disclosed in my prior U.S. Pat. Nos. 3,612,898; 3,692,650; and 5,324,405 (“'405 patent”). The '405 patent teaches an improvement over the systems disclosed in the earlier patents in terms of increasing the current distribution or throw of the current along a pipeline or well casing as well as increasing the protection of neighboring pipelines or well casings. This improvement is accomplished by the limiting current flow in the power supply through the use of back emf current limiting means. The disclosure of the '405 patent is incorporated herein by reference.
A typical prior art pulsed protection system is illustrated in FIG. 1 of the drawings where reference numerals 10 , 12 and 14 designate a D.C. voltage source, an anode/cathode voltage switch and a pulse width/frequency control unit, respectively. The positive output is supplied to an anode unit 16 (which may comprise several discrete metal cylinders connected in parallel) via a positive terminal 18 and the negative output is supplied to a plurality of well casings or pipelines 20 and 22 via the negative terminal 24 . A diode 25 (or a back emf limiter as taught in the '405 patent) is connected across the output terminals 18 and 24 . The voltage and current waveforms V and I of the output, appearing across the terminals 18 and 24 , are shown in FIG. 1 to the right of the switch 12 . As is pointed out in the '405 patent the use of diode 25 protects the voltage source from reverse voltage spikes at the expense of somewhat limiting the current throw and the protection for neighboring structures where a single current source is used.
A problem has arisen when a single pulsed D.C. source is used to protect two or more structures from a single anode unit where the spacial distances between the structures and/or the electrical properties of the soil or other conducting medium result in one or more structures receiving excessive current while others receive inadequate current for protective purposes. The use of a separate anode unit and pulsed sources for each neighboring well casing or pipeline has its own set of problems as is alluded to in the '405 patent. An under protected well casing or pipeline located in adverse soil conditions may need frequent replacement. The cost of replacing a damaged well casing or section of pipeline can be very expensive. For example, the cost to replace a deep well casing may run as much or more than one million dollars. Thus, the problem has serious economic consequences.
There is a need for an improved cathodic protection system capable of adequately protecting multiple adjacent structures such as well casings and the like which are not amenable to the use of a single pulsed source.
SUMMARY OF THE INVENTION
A system for the effective cathodic protection of a plurality of spaced electrically conducting structures such as ferrous metal pipe lines or well casings exposed to an electrically conducting medium, such as the ground, in accordance with the present invention comprises a plurality of pulsed D.C. current sources with each source being adapted to be connected to a separate structure. Each current source is arranged to supply a current pulse of a controllable amplitude to the associated structure at a selected frequency. A control circuit is coupled to each current source and arranged to synchronize the operation of the current sources so that the current pulses of all current sources occupy substantially the same time frame during each cycle. In other words, each of the current pulses during a cycle is initiated at substantially the same time and the decay of each of the current pulses begins at the same time. The magnitude of the current from each of the current sources may be separately adjusted to provide the proper amount of current to each structure to ensure its protection. By the same token, the pulse width and cycle frequency of all the current sources may be adjusted as desired.
It is to be noted that it is the rise or rise time of the current pulses from the several pulsed D.C. current sources which is controlled to occur during the same time frame. The decay of the current pulses is dependant on the impedance of the load, i.e., the anode, cathode (or well casing, pipelines etc.) and the intervening conducting medium such as the soil. The term current rise or current rise time refers to the time frame in which the current pulse is initiated until the current pulse begins to decay. Thus, the terminology setting the pulse width of the current pulses means setting the current use time for such pulses.
The construction and operation of the present invention can best be understood by the following description taken in conjunction with the accompanying drawings in which like components are designated by like reference numerals.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a state of the art pulsed cathodic protection system in which current pulses from a single source are applied between a single anode unit and two buried structures, such as well casings;
FIG. 2 is a block diagram of a cathodic protection system for protecting a plurality of structures, such as well casings or pipe lines, with the use of multiple pulsed D.C. sources, in accordance with the present invention;
FIG. 3 is a block diagram of several components of a pulsed current source;
FIG. 4 is a circuit diagram, in block and schematic form, of a pulsed current source utilizing a D.C. to D.C. converter for controlling the current amplitude of the output pulse in accordance with the present invention;
FIG. 5 is a schematic/block diagram of a D.C. to D. C. converter; and
FIG. 6 is a circuit diagram partially in block and schematic form of another embodiment of a pulsed current source suitable for use in the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 2 a cathodic protection system, in accordance with the present invention, comprises a group of pulsed D.C. sources 26 , 28 , 30 and 32 with each source having a negative output terminal 26 b, 28 b, 30 b and 32 b arranged to be connected to a separate ferrous metal structure such as a well casing (or pipe line) 34 , 36 , 38 and 40 as illustrated.
The positive output terminals 26 a, 28 a, 30 a, and 32 a of the D.C. sources are connected to an anode unit, as shown, which is submersed in the same electrically conducting medium as the well casings, e.g., the ground. A frequency and pulse width control circuit 42 is connected to each of the pulsed D.C. sources to set the width of the voltage and current pulses as well as the frequency of such pulses produced across the output terminals.
The control circuit 42 may include manually controllable knobs 42 b and 42 c for setting the frequency and pulse width of the voltage and current output pulses from the pulsed sources. The waveform of the voltage across the output terminals of the D.C. source 26 is shown at 26 e in the diagram in the left hand portion of FIG. 2 with the generally square wave output voltage pulses occurring during the same time frame during each cycle i.e., t o to t 1 , t 2 to t 3 etc. The output voltage pulses from the other pulsed D.C. sources, although not shown, will also be in the form of square waves and occupy the same time frame during each cycle as the pulses from the source 26 . The current pulses (i.e., rise times) supplied by the D.C. sources to the several well casings 34 , 36 , 38 and 40 and anode unit 41 , which occupy the same time frame as the voltage pulses, are designated as i 1 , i 2 , i 3 and i 4 , as illustrated. As pointed out previously, the time frame (or width) of the current pulses refers to the rise times of such pulses, i.e., the time from t o to t 1 , t 2 to t 3 in the waveform diagram of FIG. 2 .
As the impedance between the anode and the well casings increases, due to increased distance and/or more resistive soil conditions, greater current is required to provide the necessary protection. As is illustrated in the waveform diagram, by way of example, the magnitude of the current pulse supplied by the D.C. source 32 is greater than the magnitude of the output current pulse from the D.C. source 26 . The amplitude or magnitude of the output current pulses from each D.C. source is adjustable. The D.C. sources may include manual control means such as knobs 26 d, 28 d, 30 d, and 32 d for adjusting the magnitude of the output current pulses. There are a myriad of well known and conventional ways to adjust the frequency, pulse width and magnitude of the output current pulses from the pulsed D.C. sources. If desired, such parameters could be controlled by a computer.
Once the system of FIG. 2 is installed in the field, well head potential measuring electrodes are typically positioned adjacent the well heads or pipelines which are connected to the pulsed D.C. sources. The desired pulse width and frequency of the output voltage and current pulses are set by the control circuit 42 . The magnitudes of the output current pulses (typically the mean or average value of the output current) from the several D.C. sources are then adjusted until the proper protection of each well casing is achieved. It should be noted that an adjustment of the amplitude of the output current from one D.C. source may and probably will change the current flow from one or more of the other D.C. sources to their associated casings. Thus, it is often necessary to make several successive adjustments of the output current amplitude of the several D.C. sources. It should also be noted that it may be necessary to reset the pulse width and frequency during the adjustment period.
Referring now to FIG. 3 the basic components of a pulsed D.C. source suitable for use in the system are illustrated. A D.C. voltage source 44 , which may be in the form of a rectified (and filtered) A.C. voltage, is connected to the input of a current amplitude control circuit 46 . The output of the amplitude control circuit is supplied to the associated well casing or pipeline and the anode unit via an anode/cathode voltage switch 48 . The pulse width and frequency control circuit 42 supplies a common output signal on four output terminals collectively identified as 42 a to input circuits such as input circuit 26 e to control controls the operation of the associated anode/cathode switch to set the frequency and width of the output pulses from all of the current sources. The amplitude of the output current, once set by an operator, is maintained substantially constant by means of a current sensing resistor unit 50 connected in a conventional feedback loop well known to those skilled in the art. It should be noted that the current sensing resistor 50 will typically include appropriate filtering to provide an output voltage thereacross which is representative of the mean or average current.
A diode 52 is connected across the output terminals for protecting the switch 48 from high inverse voltages. As is pointed out in the '405 patent, this diode may be replaced with a back emf limiter to increase the current throw at the expense of reverse voltage spikes, if desired.
An additional breakdown of the components for use in a pulsed D.C. source are shown in FIG. 4 wherein an A.C. source supplies current to D.C. to D.C. converter 58 via full wave bridge rectifier 56 . The output of the D.C. to D.C. converter is applied to a group of silicon controlled rectifiers (“SCRs”) 60 , 62 , 64 and 66 which are controlled from a frequency control circuit 67 via a conventional trigger circuit 68 to form, in conjunction with capacitor 70 , a capacity charge/discharge circuit. The capacitor 70 is connected between the anode/cathode junctions of the SCRs as shown also functions to double the voltage from the converter 56 . SCRs 60 , 66 and 62 , 64 are triggered to conduct alternately in a conventional manner, as is more fully explained in the '405 patent. The size (or value) of the capacitor 68 sets the pulse width of the output pulses supplied to the load. In this embodiment the control circuit 62 need only set the frequency and synchronize the outputs of the several D.C. pulse sources.
The D.C. to D.C. converter is provided with a feedback voltage from a current sensing resistor unit 50 to maintain the current output at an adjusted setting.
One type of D.C. to D.C. converter which may be employed is illustrated in FIG. 5 in which the rectified A.C. is filtered via capacitor 74 and applied to the primary winding of an isolation transformer 76 in series with the collector-emitter circuit of a switching power transistor such as an IGBT. The secondary winding of the transformer supplies the pulsed output current through an isolation diode 80 to an anode/cathode voltage switch and to the negative output terminal. A filter capacitor 82 is connected across the output terminals as shown.
The current sensing resistor unit 50 , connected in series with the negative output terminal (or positive, if desired) supplies a feedback voltage via leads 84 , 86 to an amplitude reference circuit 88 . The amplitude of the reference signal in circuit 88 may be adjusted by knob 90 A (like knob 26 a of circuit 26 ) connected, for example, to a potentiometer in a conventional manner. The output signal on lead 88 a from the amplitude reference circuit is representative of the difference between the amplitude of the reference signal and the voltage on leads 84 , 86 which in turn is representative of the mean or average amplitude of the pulsed current output to the anode unit/well casing. The feedback signal on lead 92 is supplied to a pulse width modulator 94 via an isolator circuit 90 . The pulse width modulator, which operates at a high frequency such as 20 to 200 Khz or more to provide accurate control of the amplitude of the output current, controls the base or gate electrode of the switching transistor 78 . It should be noted that when used in the present application it is not necessary to include the isolation transformer 76 or diode 80 .
It should be noted that if a D.C. to D.C. converter is used with a non-capacitance discharge anode/cathode switch such as a transistor, e.g., an Isolated Gate Bi polar transistor (IGBT), then the control circuit must set the pulse width as well as the frequency.
Another example of a pulsed D.C. source is illustrated in FIG. 6 wherein an adjustable current amplitude current control circuit 96 is placed on the A.C. side of a pulsed D.C. source with a power switching transistor 98 such as an IGBT serving as the anode/cathode voltage switch. A trigger circuit 100 under the control of the frequency and pulse width control circuit 42 sets the frequency and pulse width of the output pulses. The current amplitude control circuit 96 , which may utilize SCRs or Triacs in a well known manner to adjustably control the portion of each half cycle of the input sine wave supplied to the bridge rectifier, receives a feedback signal on lead 101 . The feedback signal from the current sensing resistor unit 50 is representative of the load (anode/cathode) current. The control circuit 96 , in response to the feedback signal maintains the value of the adjusted current output to the bridge rectifier substantially constant.
It should be noted that while an SCR or Triac type amplitude control circuit 96 will operate satisfactorily to control the magnitude of the current pulses to the load these circuits are inherently inefficient because of power losses in the SCRs or Triacs. In contrast, D.C. to D.C. converters are typically much more efficient due to the low resistance drop through the switching transistor.
There has thus been described a cathodic protection system and method for providing improved protection for multiple structures such as well casings or pipelines. While the invention has been described in connection with several embodiments, it is not intended that the scope of the invention be limited to such embodiments and examples discussed above. Various alternatives, modifications, and equivalents will become apparent to those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims. | A cathodic protection system for protecting buried conducting structures, subject to corrosion such as well casings, pipe lines and the like, utilizes a plurality of pulsed D.C. current sources with the negative output terminal of each source connected to a separate structure and the positive output terminal of the sources connected to a common anode located near the structures. A control circuit synchronizes the operation of the several D.C. sources and sets the frequency and width of the output pulses. The amplitude of the output pulses from each D.C. source may be separately adjusted. | 2 |
CROSS-REFERENCE TO COPENDING APPLICATION
This application is a division of copending application Ser. No. 569,026, filed Apr. 17, 1975, now U.S. Pat. No. 4,022,821 which is a division of application Ser. No. 462,006, filed Apr. 18, 1974, now abandoned, which is a continuation-in-part of application Ser. No. 383,007, filed July 26, 1973, now U.S. Pat. No. 3,922,302.
BACKGROUND OF THE INVENTION
The prostaglandins are a group of hormone-like substances which may be viewed as derivatives of prostanoic acid. Several prostaglandins are found widely distributed in mammalian tissue and have been isolated from this source. These prostaglandins have been shown to possess a variety of biological properties such as bronchodilation, the ability to reduce gastric secretion, to modify muscle tone, as well as the ability to raise or lower blood pressure.
Various derivatives of prostaglandins have also been synthesized and reported. 9,15-Dihydroxy prost-13-enoic acid and methods of synthesis thereof are disclosed in U.S. Pat. Nos. 3,432,541 and 3,455,992. 9-Oxo-15-hydroxy-15-methyl-prostanoic acid, 15-oxo-9-hydroxy-prostanoic acid, and 9,15-dioxo prostanoic acid are disclosed in U.S. Pat. No. 3,671,570.
The present invention concerns a number of new intermediates useful in the synthesis of 9-oxo-15-hydroxy-15-methylprostanoic acid as well as new unsaturated 15-methyl derivatives which are themselves useful. In addition 9-oxo-15-hydroxy-15-ethynyl prostanoic acids and new intermediates thereto are included.
SUMMARY OF THE INVENTION
The invention sought to be patented in a first composition aspect resides in the concept of a chemical compound which is prostanoic acid of the structure: ##STR2## wherein R is methyl, A is cis--CH=CH-- and B is trans--CH=CH--; R is ethynyl, A is --CH 2 --CH 2 -- and B is CH 2 --CH 2 --; R is ethynyl, A is --CH 2 --CH 2 -- and B is trans--CH=CH--; or R is ethynyl, A is cis--CH=CH-- and B is trans--CH=CH--; and R 1 is hydrogen, alkyl of from 1 to about 6 carbon atoms, alkali metal, or a pharmacologically acceptable cation derived from ammonia or a basic amine.
The tangible embodiments of the first composition aspect of the invention possess the inherent general physical properties of being clear to yellow oils, or crystalline solids, and when R 1 is hydrogen are substantially insoluble in water and are generally soluble in organic solvents such as ethyl acetate and ether. Examination of the compounds produced according to the hereinafter described process reveals, upon infrared, nuclear magnetic resonance, and mass spectrographic analysis, spectral date supporting the molecular structures herein set forth. The aforementioned physical characteristics, taken together with the nature of the starting materials, the mode of synthesis, and the elemental analyses, confirm the structure of the compositions sought to be patented.
The tangible embodiments of the first composition aspect of the invention possess the inherent applied use characteristic of exerting bronchodilating effects upon administration to warm-blooded animals as evidenced by pharmacological evaluation according to standard test procedures.
The invention sought to be patented in a second composition aspect resides in the concept of a chemical compound which is a prostanoic acid of the structure: ##STR3## wherein A is --CH 2 --CH 2 -- and X is ##STR4## A is cis--CH=CH-- and X is ##STR5##
The tangible embodiments of the second composition aspect of the invention possess the inherent general physical properties of being clear to yellow oils, are substantially insoluble in water and are generally soluble in organic solvents such as ethyl acetate and ether.
Examination of the compounds produced according to the hereinafter described process reveals, upon infrared, nuclear magnetic resonance, and mass spectrographic analysis, spectral data supporting the molecular structures herein set forth. The aforementioned physical characteristics, taken together with the nature of the starting materials, the mode of synthesis, and the elemental analyses, confirm the structure of the compositions sought to be patented.
The embodiments of the second composition aspect of the invention possess the inherent applied use characteristics of being useful as intermediates for the synthesis of other compositions of the invention having bronchodilating activity, and, in addition, those compounds having a cis-5-en, a trans-13-ene, a 9-hydroxy group and having in the 15-position either a keto group or a hydrogen and hydroxy substituent, or those having hydroxy and methyl substituents at the 15-position are intermediates for the synthesis of 9-oxo-15-hydroxy-15-methyl-prostanoic acid.
The invention sought to be patented in its process aspect resides in the concept of a method of relieving bronchial spasm and facilitating breathing in warm-blooded animals which comprises administering to a warm-blooded animal in need thereof an amount sufficient to relieve bronchial spasm and facilitate breathing in said warm-blooded animal of a prostanoic acid of the formfula: ##STR6## wherein R is methyl, A is a cis--CH=CH-- and B is trans--CH=CH--; R is ethynyl, A is --CH 2 --CH 2 -- and B is --CH 2 --CH 2 --; R is ethynyl, A is --CH 2 --CH 2 -- and B is trans--CH=CH--; or R is ethynyl, A is cis--CH=CH-- and B is trans--CH=CH--; and R 1 is hydrogen, alkyl of from 1 to about 6 carbon atoms, alkali metal, or a pharmacologically acceptable cation derived from ammonia or a basic amine.
The invention sought to be patented in a third composition aspect resides in the concept of a chemical compound which is a prostanoic acid of the structure ##STR7##
The tangible embodiments of the third composition aspect of the invention possess the inherent general physical properties of being clear to yellow oils, are substantially insoluble in water, and are soluble in organic solvents such as ethylacetate and ether.
Examination of the compounds produced according to the hereinafter described process reveals, upon infrared, nuclear magnetic resonance and mass spectrographic analysis, spectral data supporting the molecular structure herein set forth. The aforementioned physical characteristics, taken together with the mode of synthesis, and the elevated analyses, confirm the structure of the compositions sought to be patented. The embodiments of the third composition aspect of the invention possess the inherent applied use characteristic of being intermediates in the synthesis of compounds of Formula I wherein R is ethynyl, A is cis--CH=CH--, and B is trans--CH=CH--.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In describing the synthesis of the compositions of the invention reference will be made to FIGS. 1, 2, and 3 wherein the formulae representing the various embodiments of the invention have been assigned Roman numerals for purposes of identification.
FIG. 1 illustrates the synthesis of a specific embodiment of Formula I namely: 7-(2β-[(3RS)-3-hydroxy-3-methyl-trans-1-octenyl]-5-oxo-1α-cyclopentyl)-cis-5-heptenoic acid (IX) and the synthesis of specific embodiments of Formula II namely: 7-(5α-hydroxy-2β-[(3R)-3-hydroxy-trans-1-octenyl]-1α-cyclopentyl)-cis-5-heptenoic acid (VI); 7-(5β-hydroxy-2β-[(3R)-3-hydroxy-trans-1-octenyl]-1α-cyclopentyl)-cis-5-heptenoic acid (VII); 7-(5α-hydroxy-2β-[3-oxo-trans-1-octenyl]-1α-cyclopentyl)-cis-5-heptenoic acid (V); 7-(5α-hydroxy-2β-[(3RS)3-hydroxy-3-methyl-trans-1-octenyl]-1.alpha.-cyclopentyl)-cis-5-heptenoic acid (VIII); 5α-hydroxy-2β-[(3RS)-3-hydroxy-3-methyl-trans-1-octenyl]-1.alpha.-cyclopentane-heptanoic acid (X); and the synthesis of the known compound 2β-[(3RS)-3-hydroxy-3-methyloctyl]-5-oxo-1α-cyclopentaneheptanoic acid (XII).
FIG. 2 illustrates the synthesis of other embodiments of Formula I namely 2β-[(3RS)-3-ethynyl-3-hydroxy-trans-1-octenyl]-5-oxo-1α-cyclopentane heptanoic acid (XVI); 2β-[(3RS)-3-ethynyl-3-hydroxy-octyl]-5-oxo-1α-cyclopentane heptanoic acid (XXII); and 7-(2β-ethynyl-3-hydroxy-trans-1-octenyl]-5-oxo-1α-cyclopentyl)-cis-5-heptenoic acids (XIX); and of other embodiments of Formula II namely: 7-(5β-hydroxy-2β-[3-oxo-trans-1-octenyl]-1α-cyclopenty-l0-cis-5-heptenoic acid (XVII); 2β-[(3RS)-3-ethynyl-3-hydroxy octyl]-5β-hydroxy-1α-cyclopentane heptanoic acid (XXI); 2β-[(3RS)-3-ethynyl-3-hydroxy-trans-1-octenyl]-5β-hydroxy-1.alpha.-cyclopentane heptanoic acid (XV) and 7-(2β-[(5RS)-3-ethynyl-3-hydroxy-trans-1-octenyl]-5β-hydroxy-1.alpha.-cyclopentyl)-cis-5-heptenoic acid (XVIII).
FIG. 3 illustrates an alternative synthesis of XIX utilizing the embodiments of Formula XXIII, namely 7-(7β-[(3RS)-3-ethynyl-3-hydroxy-trans-1-octenyl]-1,4-dioxaspiro[4,4]non-6α-yl)-cis-5-heptenoic acid (XXIII).
The starting materials in the synthesis of the compositions of the invention, namely 15-epi PGA 2 (III), and PGA 2 (IV) are well-known in the art. For example, 15-epi PGA 2 may be obtained from the coral Plexaura homomalla by a procedure as described by A. Weinheimer and R. Spraggins in Tetrahedron Letters, 59, 5185 (1969), and PGA 2 may, if desired, be prepared from 15-epi PGA 2 by an epimerization procedure as described by Bundy et al. in Annals of the New York Academy of Sciences, 180, 76, (April 30, 1971). Sodium borohydride reduction of either III or IV yields a mixture of compounds VI and VII wherein the hydroxyl group at the C-15 position will have an orientation corresponding to that of the starting material selected. Compounds VI and VII may, if desired, be separated by chromatography. Oxidation of VI with dichlorodicyanoquinone (DDQ) gives the enone V. Treatment of V with methyl magnesium bromide gives VIII which may be converted to IX by a Jones oxidation, or hydrogenated using tris(triphenylphosphine)rhodium (I) chloride to give X. Jones oxidation of X gives XI which may be hydrogenated using a palladium on charcoal catalyst to give XII.
If desired, compounds VII may be monohydrogenated using tris-(triphenyl-phosphine)-rhodium (i) chloride to give compound XIII. Oxidation of XIII using DDQ gives XIV. Reaction of XIV and ethynyl magnesium bromide gives XV. Jones oxidation of XV gives compound XVI.
DDQ oxidation of compound VII gives compound XVII. Reaction of XVII with ethynyl magnesium bromide gives XVIII which is converted, if desired, to XIX. Upon chromatography of XIX two products are isolated which are C-15 isomers, and which exhibit identical infrared, nuclear magnetic resonance, and mass spectra.
Hydrogenation of XVII using a palladium on charcoal catalyst gives compound XX which when treated with ethynyl magnesium bromide is converted to XXI. Jones oxidation of XXI gives XXII.
It will be obvious to one skilled in the art that compound VII or mixtures of compounds VI and VII may be substituted for compound VI as starting intermediate in the synthesis of IX and XII and that the intermediates thereto which correspond to V, VIII, and X will have the ring-hydroxyl group in a spatial orientation corresponding to that of the starting intermediate selected.
Similarly compound VI or mixtures of compound VI and VII may be substituted for compound VII as starting intermediate in the synthesis of XVI, XIX, and XXII, and the intermediates thereto namely those corresponding to XIII, XIV, XV, XVII, XVIII, XX, and XXI will similarly have the ring-hydroxyl group in a spatial orientation corresponding to that of the starting intermediate selected.
Jones oxidation of compound VI or VII or mixtures thereof gives 7-[2β-(3-oxo-trans-1-octenyl)-5-oxo-1α-cyclopentyl]-cis-5-heptenoic acid (XXIV). If desired, XXIV may be isolated by standard techniques. Chromatography on silica gel is a convenient method. Treatment of XXIV with ethylene glycol in the presence of an acid catalyst and inert solvent, while removing the water formed gives 7-(7β-[3-oxo-trans-1-ocetnyl]-1,4-dioxaspiro[4,4]non-6α-yl)cis-5-heptenoic acid (XXV). If desired, XXV may be isolated by standard techniques. Chromatography on silica gel is a convenient method. Ethynylation of XXV gives XXIII. XXIII may, if desired, be separated by standard techniques. Chromatography on silica gel is a convenient method and enables the separation of C-15 isomers, which are formed by the synthesis reaction. Treatment of XXIII with aqueous acid gives XIX. The orientation of the C-15 isomer of XIX so obtained will correspond to that of XXIII used. If desired, XIX may be isolated by standard techniques. Chromatography on silica gel is a convenient method.
It will be apparent to those skilled in the art of chemistry that the carbon atoms on the octane side chain to which hydroxyl substituents are attached are assymetric carbon atoms, and as a consequence these positions can be either of two epimeric configurations. The symbol where used in this specification is to indicate that both possible configurations at each particular position is intended and is included within the scope of the invention.
The esters of formula I (R 1 is alkyl) are prepared by standard methods, such as for example, by treating a solution of the free acids with diazomethane or other appropriate diazohydrocarbons, such as diazoethane, 1-diazo-2-ethylpentane, and the like. The alkali metal carboxylates of the invention can be prepared by mixing stoichiometrically equivalent amounts of the free acids of formula I, preferably in aqueous solution, with solutions of alkali metal bases, such as sodium, potassium, and lithium hydroxides or carbonates, and the like, then freeze drying the mixture to leave the product as a residue. The amine salts can be prepared by mixing the free acids, preferably in solution, with a solution of the appropriate amine, in water, isopropanol, or the like, and freeze drying the mixture to leave the product as a residue.
The term "alkyl of from about 1 to about 6 carbon atoms " when used herein and in the appended claims includes straight and branched chain hydrocarbon radicals, illustrative members of which are methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, n-pentyl, n-hexyl, 3-methylpentyl, 2,3-dimethylbutyl, and the like. "Alkali metal" includes, for example, sodium, potassium, lithium, and the like. A "pharmacologically-acceptable cation derived from ammonia or a basic amine" contemplates the positively charged ammonium ion and analogous ions derived from organic nitrogenous bases strong enough to form such cations. Bases useful for the purpose of forming pharmacologically-acceptable non-toxic addition salts of such compounds containing free carboxyl groups form a class whose limits are readily understood by those skilled in the art. Merely for illustration, they can be said to comprise, in cationic form, those of the formula: ##STR8## wherein R 1 , R 2 , and R 3 , independently, are hydrogen, alkyl of from about 1 to about 6 carbon atoms, cycloalkyl of from about 3 to about 6 carbon atoms, monocarbocyclicaryl of about 6 carbon atoms, monocarbocyclicarylalkyl of from about 7 to about 11 carbon atoms, hydroxyalkyl of from about 1 to about 3 carbon atoms, or monocarbocyclicarylhydroxyalkyl of from about 7 to about 15 carbon atoms, or, when taken together with the nitrogen atom to which they are attached, any two of R 1 , R 2 , and R 3 form part of a 5 to 6-membered heterocyclic ring containing carbon, hydrogen, oxygen, or nitrogen, said heterocyclic rings and said monocarbocyclicaryl groups being unsubstituted or mono- or dialkyl substituted, said alkyl groups containing from about 1 to about 6 carbon atoms. Illustrative therefore of R groups comprising pharmacologically-acceptable cations derived from ammonia or a basic amine are ammonium, mono-, di-, and trimmethylammonium, mono-, di- and triethylammonium, mono-, di-, and tripropylammonium (iso and normal), ethyldimethylammonium, benzyldimethylammonium, cyclohexylammonium, benzylammonium, dibenzylammonium, piperidinium, morpholinium, pyrrolidinium, piperazinium, 1-methylpiperidinium, 4-ethylmorpholinium, 1-isopropylpyrrolidinium, 1,4-dimethylpiperazinium, 1-n-butyl-piperidinium, 2-methylpiperidinium, 1-ethyl-2-methylpiperidinium, mono-, di- and triethanolammonium, ethylidiethanolammonium, n-butylmonoethanolammonium, tris(hydroxymethyl)-methylammonium, phenylmonoethanolammonium, and the like.
In practicing the method of the invention, the instant compositions can be administered in a variety of dosage forms, the oral route being used primarily for maintenance therapy while injectables tend to be more useful in acute emergency situations. Inhalation (aerosols and solution for nebulizers) seems to be somewhat faster acting than other oral forms but slower than injectables and this method combines the advantages of maintenance and moderately-acute stage therapy in one dosage unit.
The daily dose requirements vary with the particular compositions being employed, the severity of the symptoms being presented, and the animal being treated. The dosage varies with the size of the animal. With large animals (about 70 kg. body weight), by the oral inhalation route, with for example a hand nebulizer or a pressurized aerosol dispenser the dose is from about 5 micrograms to about 100 micrograms, and preferably from about 10 to about 50 micrograms, approximately every four hours, or as needed. By theoral ingestion route, the effective dose is from about 1 to about 20 mg., preferably from about 5 to about 15 mg. up to a total of about 40 mg. per day. By the intravenous route, the ordinarily effective dose is from about 50 micrograms to about 300 micrograms, preferably about 200 micrograms per day.
For unit dosages, the active ingredient can be compounded into any of the usual oral dosage forms including tablets, capsules and liquid preparations such as elixirs and suspensions containing various coloring, flavoring, stabilizing and flavor masking substances. For compounding oral dosage forms the active ingredient can be diluted with various tableting materials such as starches of various types, calcium carbonate, lactose, sucrose and dicalcium phosphate to simplify the tableting and capsulating process. A minor proportion of magnesium stearate is useful as a lubricant. In all cases, of course, the proportion of the active ingredient in said composition will be sufficient to impart bronchodilating activity thereto. This will range upward from about 0.0001% by weight of active ingredient in said composition.
For administration by the oral inhalation route with conventional nebulizers or by oxygen aerosolization it is convenient to provide the instant active ingredient in dilute aqueous solution, preferably at concentrations of about 1 part of medicament to from about 100 to 200 parts by weight of total solution. Entirely conventional additives may be employed to stabilize these solutions or to provide isotonic media, for example, sodium chloride, sodium citrate, citric acid, sodium bisulfite, and the like can be employed.
For administration as a self-propelled dosage unit for administering the active ingredient in aerosol form suitable for inhalation therapy the composition can comprise the active ingredient suspended in an inert propellant (such as a mixture of dichlorodifluoromethane and dichlorotetrafluoroethane) together with a co-solvent, such as ethanol, flavoring materials and stabilizers. Instead of a co-solvent there can also be used a dispersing agent such as oleyl alcohol. Suitable means to employ the aerosol inhalation therapy technique are described fully in U.S. Pat. Nos. 2,868,691 and 3,095,355, for example.
The following examples further illustrate the best mode contemplated by the inventor of making the compositions of the invention.
EXAMPLE 1
7-(5α-Hydroxy-2β-[(3R)-3-Hydroxy-Trans-1-Octenyl]-1α-Cyclopentyl)-Cis-5-Heptenoic Acid
and
7-(5β-Hydroxy-2β-[(5R)-3-Hydroxy-Trans-1-Octenyl]-1α-Cyclopentyl)-Cis-5-Heptenoic Acid
An ice-cooled solution of 4.0 g. of 7-(2β-[(3R)-3-hydroxy-trans-1-ocetenyl]-5-oxo-1α-cyclopent-3-enyl)-cis-5-heptenoic acid in 110 ml. of a 10:1 mixture methanol water is treated with 2.2 g. of sodium borohydride, and stirred at 25° for 7 hours. The mixture is concentrated under vacuum at 40°, the residue diluted with water, acidified with acetic acid and the mixture partitioned with ether. After washing and drying, the extract is evaporated and the residue chromatographed on silica. Elution with 35% ethyl acetate-hexane affords the first title product as an oil, λ max film 2.95, 3.4, 5.8, 7.1, 8.1, 8.8, 9.7, 10.3 μ NMR: δ 5.48 (M, 4, olefinic H), 4.62 (2, OH), 4.28 (M, 2, 9 and 15-H) ppm. Mass spectrum: M + at m/e (theory 338), M + -H 2 O at m/e 320.2331 (theory 320.2350).
Further elution with 40% ethyl acetate-hexane gives the second title product as an oil, λ max film 3.0, 3.4, 5.8, 7.1, 8.1, 9.35, 10.3 μ NMR: δ 5.55 (M, 4, olefinic H), 4.58 (s, OH), 4.05 (M, 2, 9 and 15-H) ppm. Mass spectrum: M + at m/e 338 (theory 338). M + -H 2 O at m/e 320.2384 (theory 320.2350).
EXAMPLE 2
7-[5α-Hydroxy-2β-(3-Oxo-Trans-1-Octentyl)-1α-Cyclopentyl]-Cis-5-Heptenoic Acid
A solution of 3.63 g. of 7-(5α-hydroxy-2β-[(3R-3-hydroxy-trans-1-octenyl]-1α-cyclopentyl)-cis-5-heptenoic acid in 250 ml. of dioxane is treated with 3.63 g. of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and stirred at 55° for 40 hours under nitrogen. The solution is concentrated under vacuum at 40° and the residue chromatographed on silica. Elution with 30% ethyl acetate-hexane yields 1.8 g. of the title product as an oil, λ max film 3.0 (shoulder), 3.4, 5.8, 6.0 (shoulder), 6.15 (shoulder), 7.1, 8.1, 10.2 μ UV: λ max EtOH 232 mμ (ε 12,000). NMR: δ 6.72 (dd, 1, J=5.3 and 15, 13-H, 6.08 (d, 1, J=15, 14-H), 5.40 (M,2,5 and 6-H), 4.25 (M, 1, 9-H) ppm. Mass spectrum: QM + at m/e 337 (theory 337), QM + -H 2 O at m/e 319 (theory 319).
EXAMPLE 3
7-(5α-Hydroxy-2β-[(3RS)-3-Hydroxy-3-Methyl-Trans-1-Octenyl]-1.alpha.-Cyclopentyl)-Cis-5-Heptenoic Acid
An ice-cooled solution of 1.7 g. of 7-[5α-hydroxy-2β-(3-oxo-trans-1-octenyl)-1α-cyclopentyl]-cis-5-heptenoic acid in 150 ml. of tetrahydrofuran is treated with 15 ml. of 3M methyl magnesium bromide in ether dropwise over 10 minutes, under nitrogen. After stirring at 0° for 45 minutes, the mixture is added to ammonium chloride solution, acidifed with acetic acid and extracted with ether. After washing and drying, the extract is evaporated and the residue chromatograhed on silica. Elution with 35% ethyl acetate-hexane affords 1.07 g. of the title product as an oil, λ max film 3.0, 3.4, 5.8, 8.1, 10.3 μ NMR: δ 5.42 (M, 4, olefinic H), 5.12 (s, 3, OH), 4.20 (M, 1, 9-H), 1.28 (s, 15-CH 3 ) ppm. Mass spectrum: QM + -H 2 O at m/e 335 (theory 335).
EXAMPLE 4
7-(2β-[(3RS)-3-Hydroxy-3-Methyl-Trans-1-Octenyl]-5-Oxo-1α-Cyclopentyl)-Cis-5-Heptenoic Acid
An ice-cooled solution of 1.02 g. of 7-(5α-hydroxy-2β-[(3RS)-3-hydroxy-3-methyl-trans-1-octenyl]-1.alpha.-cyclopentyl)-cis-5-heptenoic acid in 80 ml. of acetone is treated dropwise with Jones reagent until the orange color persists. After stirring at 0° for 1/2 hour, the mixture is treated with 5 ml. of methanol and dilute sodium bicarbonate until basic. The mixture is diluted with water, acidified with acetic acid and extracted with ether. After washing and drying, the extract is evaporated and the residue chromatographed on silica. Elution with 30% ethyl acetate-hexane gives 0.12 g. of the title product as an oil, λ max film 3.0, 3.4, 5.75, 7.1, 8.15, 8.65, 10.3 μ MNR: δ 6.80 (s, 2, OH), 5.72 (M, 2, 13 and 14-H), 5.52 (M, 2, 5 and 6-H), 1.30 (s, 15-CH 3 ) ppm. Mass spectrum: QM + at m/e 351 (theory 351).
EXAMPLE 5
5α-Hydroxy-2β-[(3RS)- - Hydroxy-3-Methyl-Trans-1-Octenyl]-1α-Cyclopentane Heptanoic Acid
A solution of 2.5 g of 7-(5α-hydroxy-2β-[(3RS)-3-hydroxy-3-methyl-trans-1-octenyl]-1.alpha.-cyclopentyl)-cis-5-heptenoic acid in 35 ml. of 1:1 benzene-ethanol is added to a prehydrogenated solution of 0.63 g of tris-(triphenylphosphine) rhodium (I) chloride in 115 ml. of 1:1 benzene-ethanol and the mixture hydrogenated at 25° and atmospheric pressure until 1 equivalent of hydrogen is absorbed. Evaporation of the solvent and silica chromatography of the residue with 45% ethyl acetate-hexane gives 1.878 g. of the title product as an oil, λ max film 3.0, 3.5, 5.85, 6.85, 8.95, 10.3 μ. NMR: δ 5.55 (M,2, 13 and 14-H), 4.98 (s, 3, OH), 4.32 (M, 1, 9-H) ppm. Mass spectrum: QM + -2H 2 O at m/e 319.2636 (theory 319.2636).
EXAMPLE 6
2β-[(3RS)-3-Hydroxy-3-Methyl-Trans-1-Octenyl]-5-Oxo-1α-Cyclopentaneheptanoic Acid
An ice-cooled solution of 1.795 g. of 5α-hydroxy-2β-[(3RS)-3-hydroxy-3-methyl-trans-1-octenyl]-1.alpha.-cyclopentaneheptanoic acid in 120 ml. of acetone is treated dropwise with Jones reagent until the orange color persists. After stirring at 0° for 25 minutes, the mixture is treated with 10 ml. of methanol and dilute sodium bicarbonate until basic. Following dilution with water, the mixture is acidified with acetic acid and extracted with ether. The extract is washed, dried, evaporated and the residue chromatographed on silica. Elution with 30% ethyl acetate-hexane affords 0.33 g. of the title product as an oil, λ max film 2.95 (shoulder), 3.4, 5.75, 6.8, 8.6, 10.25 μ. NMR: δ 6.22 (OH), 5.62 (M, 13 and 14-H), 1.28, 1.28 (15-CH 3 ) ppm. Mass spectrum: QM + -H 2 O at m/e 335 (theory 335).
EXAMPLE 7
2β-[(3RS)-3-Hydroxy-3-Methyloctyl]-5-Oxo-1α-Cyclopentaneheptanoic Acid
A solution of 0.29 g. of 2β-[(3RS)-3-hydroxy-3-methyl-trans-octenyl]-5-oxo-1α-cyclopentaneheptanoic acid in 20 ml. of ethyl acetate is added to a prehydrogenated mixture of 0.09 g. of 10% Pd/C in 10 ml. of ethyl acetate and the mixture hydrogenated at 25% and atmospheric pressure for 16 hours. The mixture is filtered, evaporated and the residue chromatographed on silica. Elution with 40% ethyl acetate-hexane gives 0.16 g. of the title product as an oil, λ max film 3.0, 3.4, 5.72, 6.8, 8.65 μ NMR: 6.02 (s, OH), 1.18 (s, 15-CH 3 ) ppm. Mass spectrum: M + at m/e 354.2729 (theory 354.2768).
EXAMPLE 8
5β-Hydroxy-2β-[(3R)-3-Hydroxy-Trans-1-Octenyl]-1α-Cyclopentaneheptanoic Acid
A solution of 4.4 g. of 7-(5β-hydroxy-2β-[(3R)-3-hydroxy-trans-1-octenyl]-1α-cyclopentyl)-cis-5-heptenoic acid in 50 ml. of 1:1 benzene-ethanol is added to a prehydrogenated solution of 1.1 g. of tris-(tripenylphosphine) rhodium (I) chloride in 200 ml. of 1:1 benzene-ethanol and the mixture hydrogenated at 25° and atmospheric pressure until 1 equivalent of hydrogen is absorbed. Evaporation of the solvents and silica chromatography of the residue with 40% ethyl acetate-hexane affords 2.7 g. of the title product as an oil, λ max film 3.05, 3.4, 5.85, 6.8, 8.1, 9.8, 10.3 μ. NMR: δ 5.58 (M, 2, 13 and 14-H), 3.95 (M,2,9 and 15-H) ppm. Mass spectrum: M + at m/e 340 (theory 340), M + -H 2 0 at m/e 322.2493 (theory 322.2507).
EXAMPLE 9
5β-Hydroxy-2β-(3-Oxo-Trans-1-Octenyl)-1α-Cyclopentane Heptanoic Acid
A solution of 2.7 g. of 5β-hydroxy-2β-[(3R)-3-hydroxy-trans-1-octenyl]-1α-cyclopentane heptanoic acid in 150 ml. of dioxane is treated with 2.7 g. of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and the mixture stirred at 75° for 18 hours under nitrogen. After cooling to 25°, the mixture is filtered, diluted with ether, filtered again and washed with water. The ether solution is then extracted 4 times with aqueous saturated sodium bicarbonate and the aqueous extracts acidified with acetic acid and extracted with ether. The ether extract is combined with the original ether solution, evaporated and the residue chromatographed on silica. Elution with 40% ethyl acetate-hexane gives 1.42 g. of the title product as an oil, λ max film 3.0 (shoulder), 3.4, 5.85, 6.0 (shoulder), 6.15, 8.4, 9.35, 10.2 μ. UV: λ max EtOH 230 mμ (ε 13,200). NMR: δ 6.8 (dd, 1, J=7.5 and 15, 13-H), 6.0 (d, 1, J=15, 14-H), 3.95 (M, 1, 9-H) ppm. Mass spectrum: QM + at m/e 339 (theory 339).
EXAMPLE 10
2β-[(3RS)-3-Ethynyl-3-Hydroxy-Trans-1-Octenyl]-5β-Hydroxy-1.alpha.-Cyclopentane Heptanoic Acid
A solution of 1.42 l g. of 5β-hydroxy-2β-(3-oxo-trans-1-octenyl)-1α-cyclopentane heptanoic acid in 30 ml. of tetrahydrofuran is added to an ice-cooled solution of ethynyl magnesium bromide (made from 13.3 ml. of 3M methyl magnesium bromide and excess acetylene) in 170 ml. of tetrahydrofuran and the mixture stirred at 0° for 15 minutes and at 25° for 3 hours. The mixture is diluted with aqueous ammonium chloride solution, acidified with acetic acid and extracted with ether. After washing and drying, the extract is evaporated and the residue chromatographed on silica. Elution with 40% ethyl acetate-hexane affords 1.03 g. of the title product as an oil, λ max film 3.05, 3.4, 5.8, 9.3, 10.3 μ. NMR: δ 5.95 (dd, 1, J=7.5 and 15, 13-H), 5.4 (d, 1, J=15, 14-H), 3.92 (M, 1, 9-H, 2.58 (s, 1, acetylenic H) ppm. Mass spectrum: QM + at m/e 365 (theory 365).
EXAMPLE 11
2β-[(3RS)-3-Ethynyl-3-Hydroxy-Trans-1-Octenyl]-5-Oxo-1α-Cyclopentane Heptanoic Acid
An ice-cooled solution of 1.0 g. of 2β-[(3RS)-3-ethynyl-3-hydroxy-trans-1-octenyl]-5β-hydroxy-1.alpha.-cyclopentaneheptanoic acid in 75 ml. of acetone is treated with Jones reagent (3.9 ml.) over 20 minutes until the orange color persists. After stirring at 0° for 1/2 hour, under nitrogen, the mixture is treated with 10 ml. of methanol and dilute sodium bicarbonate until basic. Following dilution with water and acidification with acetic acid, the mixture is extracted with ether and the extract wadhed, dried and evaporated. Silica chromatography of the residue with 30% ethyl acetatehexane gives 0.27 g. of the title product as an oil, λ max film 3.05, 3.45, 5.8, 7.1, 8.65, 10.3 μ. NMR: δ 5.98 (dd, 1, J=7.5 and 15, 13-H), 5.55 (d, 1, J=13, 14-H), 2.60 (s, 1, acetylenic H) ppm. Mass spectrum: QM + at m/e 363 (theory 363).
EXAMPLE 12
7-[5β-Hydroxy-2β-(3-Oxo-Trans-1-Octenyl)-1α-Cyclopentyl]-Cis-5-Heptenoic Acid
A solution of 0.51 g. of 7-(5β-hydroxy-2β-[(3R)-3-hydroxy-trans-1-octenyl]-1α-cyclopentyl)-cis-5-heptenoic acid in 40 ml. of dioxane is treated with 0.51 g. of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and the mixture stirred at 55° for 24 hours under nitrogen. The mixture is evaporated and the residue chromatographed on silica with 40% ethyl acetate-hexane to obtain 0.38 g. of the title product as an oil, λ max film 3.0 (shoulder), 3.4, 5.85, 6.0 (shoulder), 6.15 (shoulder), 8.1, 9.3, 10.2 μ. UV: λ max EtOH 231 mμ (ε 14,050). NMR: δ 6.85 (dd, 1, J=7.5 and 16, 13-H), 6.08 (d, 1, J=16, 14-H), 5.50 (M, 2, 5 and 6-H), 4.00 (M, 1, 9-H) ppm. Mass apectrum: M + at m/3.336.2299 (theory 336.2299).
EXAMPLE 13
5β-Hydroxy-2β-(3Oxo-Octyl)-1α-Cyclopentaneheptanoic Acid
A solution of 2.68 g. of 7-[5β-hydroxy-2β-(3-oxo-trans-1-octenyl)-1α-cyclopentyl]-cis-5-heptenoic acid in 50 ml. of ethyl acetate is added to a prehydrogenated mixture of 0.67 g. of 10% Pd/C in 50 ml. of ethyl acetate and hydrogenated at 25° and atmospheric pressure until 2 equivalents of hydrogen are absorbed. The mixture is filtered, evaporated and the residue chromatographed on silica. Elution with 35% ethyl acetate-hexane affords 1.96 g. of the title product as an oil, λ max film 3.0 (shoulder), 3.4, 5.8, 6.8, 7.05, 8.2 μ. NMR: δ 6.35 (s, 2, OH), 3.95 (m, 1, 9-H), 2.2-2.6 (M, 5, CO-CH) ppm. Mass spectrum: QM + -H 2 O at m/e 323 (theory 323).
EXAMPLE 14
2β-[(3RS)-3-Ethynyl-3-Hydroxyoctyl]-5β-Hydroxy-1α-Cyclopentaneheptanoic Acid
A solution of 1.86 g. of 5β-hydroxy-2β-(3-oxo-octyl)-1α-cyclopentane heptanoic acid in 30 ml. of tetrahydrofuran is added to a solution of ethynyl magnesium bromide (made from 18.0 ml. of 3M methyl magnesium bromide in ether and excess acetylene) in 220 ml. of tetrahydrofuran and the mixture stirred at 25° for 2 hours under nitrogen. Following dilution with aqueous ammonium chloride solution and acidification with acetic acid, the mixture is extracted with ether. After washing and drying, the extract is evaporated and the residue chromatographed on silica. Elution with 40% ethyl acetate-hexane gives 1.54 g. of the title product as an oil, λ max film 3.05, 4.5, 5.8, 6.8, 9.0, 10.7 μ. NMR: δ 5.32 (s, 3, OH), 3.95 (M, 1, 9-H), 2.48 (s, 1, acetylenic H), 2.35 (M, 2, CO-CH) ppm. Mass spectrum: QM + -2H 2 O at m/e 331.2633 (theory 331.2336).
EXAMPLE 15
2β-[(3RS)-3-Ethynyl-3-Hydroxyoctyl]-5-Oxo-1α-Cyclopentane Heptanoic Acid
An ice-cooled solution of 1.45 g. of 2β-[(3RS)-3-ethynyl-3-hydroxyoctyl]-5β-hydroxy-1α-cyclopentaneheptanoic acid in 50 ml. of acetone is treated with Jones reagent (4.0 ml.) until the orange color persisted and the mixture stirred at 0° for 1/2 hour under nitrogen. The mixture is treated with 10 ml. of methanol, dilute sodium bicarbonate until basic and diluted with water. After acidification with acetic acid, the mixture is extracted with ether and the extract washed, dried and evaporated. Silica chromatography of the residue with 30% ethyl acetatehexane gives 0.32 g. of the title product as an oil, λ max film 3.05, 3.4, 4.7 (weak), 5.75, 6.8, 7.05, 8.6 μ. NMR: δ 6.02 (M, OH), 2.48 (s, acetylenic H) ppm. Mass spectrum: QM + -H 2 O at m/e 347 (theory 347).
EXAMPLE 16
7-(2β-[(3RS)-3-Ethynyl-3-Hydroxy-Trans-1-Octenyl]-5β-Hydroxy-1.alpha.-Cyclopentyl)-Cis-5-Heptenoic Acid
A solution of 9.95 g. of 7-[5β-hydroxy-2β-(3-oxo-trans-1-octenyl)-1α-cyclopentyl]-cis-5-heptenoic acid in 20 ml. of tetrahydrofuran is added to a solution of ethynyl magnesium bromide (made from 18.9 ml. of 3M methyl magnesium bromide and excess acetylene) in 270 ml. of tetrahydrofuran and the mixture stirred at 25° for 1 hour under nitrogen. The mixture is diluted with aqueous ammonium chloride solution, acidified with acetic acid and extracted with ether. Following washing and drying, the extract is evaporated and the residue chromatographed on silica. Elution with 35% ethyl acetate-hexane affords 1.55 g. of the title product as an oil, λ max film 3.05, 3.4, 5.8, 10.25 μ. NMR: δ 6.00 (dd, 1, J=7.5 and 15, 13-H), 5.52 (M, 2, 5 and 6-H), 5.48 (d, J=15, 14-H), 4.00 (M, 1, 9-H), 2.58 (s, 1, acetylenic H) ppm.
EXAMPLE 17
7-(2β-[(3R)-3-Ethynyl-3-Hydroxy-Trans-1-Octenyl]-5-Oxo-1α-Cyclopentyl)-Cis-5-Heptenoic Acid
and
7-(2β-[(3S)-3-Ethynyl-3-Hydroxy-Trans-1-Octenyl]-5-Oxo-1α-Cyclopentyl)-Cis-5-Heptenoic Acid
An ice-cooled solution of 1.415 g. of 7-(2β-[(3RS)-3-ethynyl-3-hydroxy-trans-1-octenyl]-5β-hydroxy-1.alpha.-cyclopentyl-cis-5-heptenoic acid in 80 ml. of acetone is treated with Jones reagent until the orange color persists and the mixture stirred at 0° for 1/2 hour under nitrogen. The mixture is treated with 10 ml. of methanol, dilute sodium bicarbonate until basic and diluted with water. Following acidification with acetic acid, the mixture is extracted with ether and the extract washed, dried and evaporated. The resulting residue is chromatographed on silica with 30% ethyl acetate-hexane to obtain 0.11 g. of a first product as an oil, λ max film 3.05, 3.4, 5.75, 7.05, 8.1, 8.6, 10.25 μ. NMR: δ 7.22 (s, 2, OH), 5.3-6.4 (M, 4 olefinic H), 2.60 (s, acetylenic H) ppm. Mass spectrum: M + at m/e 360 (theory 360), M + -C 2 H 2 at m/e 334.2143 (theory 334.2193).
Continued elution afforded 0.04 g. of a second product, as an oil, which exhibits spectra identical to that of the first product. On the basis of relative mobility in thin layer chromatography the second product is assigned the 3S configuration and the first product is assigned the 3R configuration.
EXAMPLE 18
Anesthetized (Dial-urethane) guinea pigs were artificially respired at a constant positive air pressure (Starling miniature pump) and changes in tidal air during inspiration were recorded, according to the method of Rosenthale et al., Int. Arch. Pharmacol., 172, 91 (1968). The bronchoconstrictor agent acetylcholine (ACH) was administered at doses of 10 to 40 meg/kg. depending on each animal's sensitivity to this compound, and control responses to acetylcholine were thus established. Bronchoconstrictor agents raise the resistance of the lungs to inflation thereby decreasing the tidal air flow. 7-(2β-[(3S)-3-ethynyl-3-hydroxy-trans-1-octenyl]-5-oxo-1α-cyclopentyl)-cis-5-heptenoic acid was then administered be aerosol, and the animals were then challenged again with acetylcholine, and the degree of inhibition of bronchoconstriction was thus determined. A minimum of two animals was used at each dose.
______________________________________Results.sup.a Mean % Protection VSTotal Aerosol Dose (mcg) ACH Bronchoconstriction______________________________________1.5 × 10.sup.-4 3210.sup.-5 5310.sup.-2 7910.sup.-1 92______________________________________ .sup.a Minimum of 2 animals per dose.
EXAMPLE 19
7-[2β-(3-Oxo-Trans-1-Octenyl)-5-Oxo-1α-Cyclopentyl]-Cis-5-Heptenoic Acid
A solution of 20.0 g. of 15-epi-PGA 2 in 500 ml. of methanol and 50 ml. of water is cooled in an ice bath and treated with 11.0 g. of sodium borohydride in portions (some foaming) with stirring. After addition of sodium borohydride, the ice bath is removed and the mixture stirred at 25° for 6 hours. The mixture is acidified with acetic acid and the solvent removed under vacuum (water aspirator) at 40°. The residue is diluted with water and extracted thrice with ether. The extract is washed thrice with brine, dried and evaporated (aspirator/40°) to yield 22 g. of oil, a mixture of C-9 alcohols. TLC (silica, 65:15:2 Bz:Diox:HAc) shows starting ketone at Rf 45 and alcohol products at Rf 42 and 48.
The above crude alcohol mixture is dissolved in 1.5 liters of acetone, cooled in an ice bath and treated with 120 ml. of 1.4M Jones reagent. After stirring at 0° for 40 minutes, the mixture is treated with 50 ml. of methanol to destroy excess Jones reagent, neutralized with dilute sodium bicarbonate solution and acidified with acetic acid. The solvent is removed (aspirator/40°) and the residue diluted with water and extracted thrice with ether. The extract is washed thrice with brine, dried and evaporated (aspirator/40°). The residue (24 g.) is chromatographed on 1.2 Kg of silicar CC-4 starting with 15% EtOAc-hexane and the oily title product (13.4 g.) is eluted with 30% EtOAc-hexane. TLC (silica 65:15:2 Bz:Diox:HAc) Rf 55. UV: λ max 95% EtOH 228 mμ (ε 13,000). λ max film 3.45, 5.75, 5.9, 6.0, 6.15, 7.1, 8.7, 10.2 μ. NMR: δ 10.7 (s, 1, OH), 6.86 (dd, 1, J=7.5 and 15, 13-H), 6.2 (d, 1, J=15, 14-H), 5.4 (m, 2, 5 and 6-H) ppm.
Analysis for: C 20 H 30 O 4 Calculated: C, 71.82; H, 9.04 Found: C, 72.01; H, 9.00
EXAMPLE 20
7-(7β-[3-Oxo-Trans-1-Octenyl]-1,4-Dioxaspiro[4.4]non-6α-yl)-Cis-5-Heptenoic Acid
A solution of 4.8 g. of 7-[2β-(3-oxo-trans-1-octenyl)-5-oxo-1α-cyclopentyl]-cis-5-heptenoic acid, 50 ml. of ethylene glycol and 80 mg. of p-toluenesulfonic acid is refluxed under nitrogen with a Dean Stark water separator for 1.5 hours. The mixture is cooled, diluted with 300 ml. of ether, washed thrice with brine and dried. The solvent is removed (aspirator/40°) and the residue (5.5 g.) chromatographed on 300 g. of silicar CC-4. The crude product is put on the column with 15% ethyl acetatehexane, allowed to stand for 4 hours and then eluted to obtain the oily title product (3.1 g.) with 20% EtAc-hexane. TLC (silica 65:15:2 Bz:Diox:HAc) shows starting diketone at Rf 50, desired C-9 monoketal at Rf 55 and C-9, 15 diketal at Rf 60. UV: λ max 95% EtOH 230 mμ (ε 12,840). λ max film 3.45, 5.75, 5.85, 6.0, 6.15, 8.7, 9.65, 10.2 μ. NMR: δ 10.2 (s, 1, OH), 6.82 (dd, 1, J=7.5 and 16.5, 13-H), 6.1 (d, 1, J=16.5, 14-H), 5.42 (m, 2, 5 and 6-H), 3.92 (s, 4, ketal H) ppm. Mass spectrum: M + at m/e 378.2423 (theory 378.2405).
EXAMPLE 21
7-(7β-[(3S)-3-Ethynyl-3-Hydroxy-Trans-1-Octenyl]-1,4-dioxaspiro[4.4]non-6α-yl)-Cis-5-Heptenoic Acid
Dry tetrahydrofuran is saturated at 25° by bubbling acetylene (through 2 dry ice-acetone traps and alumina drying tube) through with stirring for approximately 1/2 hour. A solution of 50 ml. of 3M methyl magnesium bromide/ether in 50 ml. of dry tetrahydrofuran is added dropwise and stirring continued for 1 hour with acetylene continuously bubbling through the mixture. A solution of 9.0 g. of 7-(7β-[3-oxo-trans-1-octenyl]-1,4-dioxaspiro[4.4]non-6α-yl)-cis-5-heptenoic acid in 120 ml. of dry tetrahydrofuran is added and the mixture stirred for 1 hour with acetylene continuously bubbling through the mixture. The mixture is added to ammonium chloride solution, acidified with acetic acid, and extracted thrice with ether. The extract is washed thrice with brine, dried and evaporated (aspirator/40°). Chromotography of the residue (11 g.) on 1 Kg of silicar CC-4 with 25% ethyl acetate-hexane first gives 3.9 g. of the 15-epi isomer followed by 5.2 g. of the desired oily title product. TLC (silica 65:15:2 Bz:Diox:HAc) shows starting ketal at Rf 55, title product at Rf 48. λ max film 3.0, 5.4, 4.7 (weak), 5.75, 8.6, 10.2 μ. NMR: δ 5.3-6.1 (m, 4, olefinic), 5.9 (s, 4 ketal H), 2.58 (s, C.tbd.CH)ppm. Mass spectrum: M + at m/3.404.2561 (theory 404.2558).
EXAMPLE 22
7-(2β-[(3S)-3-Ethynyl-3-Hydroxy-Trans-1-Octenyl]-5-Oxo-1α-Cyclopentyl)-Cis-5-Heptenoic Acid
A solution of 5.2 g. of 7-(7β-[(3S)-3-ethynyl-3-hydroxy-trans-1-octenyl]-1,4-dioxaspiro[4.4]non-6α-yl)-cis-5-heptenoic acid in 150 ml. of acetic acid is treated with 75 ml. of water and stirred at 25°/N 2 /1 hour. The solution is diluted with brine, extracted thrice with ether and the extract washed 5 times with brine, dried and evaporated (aspirator/40°). The crude product (5.4 g.) is chromatographed on 520 g. silicar CC-4 and the title product (3.9 g. of oil) eluted with 30% EtOAc-hexane. [α] D 25 ° (-) 58.5 (1% CHCl 3 ). λ max film 3.0, 3.35, 5.7, 7.0, 8.55, 10.2μ. NMR: δ 6.1 (dd, 1, J=7.5 and 15, 13-H), 5.65 (d, 1, J=15, 14-H) 5.48 (m, 2,5 and 6-H), 2.65 (s, C.tbd.CH)ppm. Mass spectrum: M + at m/e 360. | There is disclosed herein a process for relieving bronchial spasm and facilitating breathing in warm-blooded animals which comprises administering to a warm-blooded animal in need thereof an amount sufficient to relieve bronchial spasm and facilitate breathing in said warm-blooded animal of a prostanoic acid of the formula: ##STR1## wherein R is ethynyl, A is --CH 2 --CH 2 -- and B is --CH 2 --CH 2 --; R is ethynyl, A is --CH 2 --CH 2 --, and B is trans --CH=CH--; or R is ethynyl, A is cis --CH=CH--; and B is trans --CH=CH--; and R 1 is hydrogen, alkyl of from 1 to about 6 carbon atoms, alkali metal, or a pharmacologically acceptable cation derived from ammonia or a basic amine. | 2 |
RELATED APPLICATION
This application relies for priority upon Korean Patent Application No. 2001-34185, filed on Jun. 16, 2001.
FIELD OF THE INVENTION
The present invention generally relates to devices for restoring data from signals transmitted through plural antennas, and more particularly to terminal-specific receivers usable in various features of base-station transmission diversities.
BACKGROUND OF THE INVENTION
As is presently known, CDMA 2000 as the third-generation cellular system is in need of a larger system capacity to transmit high-speed packet data as well as audio data. Such extension of system capacity confronts several obstacles involved in inherent properties of wireless communication systems. It is well known that the most important factor in mobile communication is to reduce “fading” that causes distortions of received signals.
In overcoming fading, it is preferred to employ diversity techniques. The diversity is generally used to combat multi-path fading, being applied on both the transmission and reception sides. There are essentially three kinds of diversity: time, frequency, and space.
In the CDMA 2000 system, a forward link governs system capacity because it has a smaller channel capacity than a reverse link, in contrast to the second-generation cellular system. Those conditions arise from the fact that the forward link is available to apply the maximal ratio coupling to a reception signal on the reception diversity employing two antennas at a base station. Since applying the reception diversity of two antennas burdens a terminal, the CDMA 2000 system employs the base station transmission diversity so as to balance the difference between channel capacities of the forward and reverse links.
There have been proposed several kinds of transmission diversity techniques, such as OTD (orthogonal transmission diversity), TSTD (time-switched transmission diversity), STD (selection diversity), TXAA (transmission antenna array), and so on. It would not be apparent to discriminate superiority and inferiority between the diversity techniques about which one is capable of facilitating an optimal trade-off in view of functional enhancement in comparison with implementation complexity. It may be general to choose the best way among them in accordance with a given communication environment.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a terminal-specific receiver adaptable to various environments of base station transmission diversity such as OTD, TSTD, STD, TXAA, and so on.
In order to attain the above objects, according to an aspect of the present invention, there is provided a data regeneration device. The device includes a plurality of despreading units for regenerating pilot and data signals by means of pilot and data Walsh codes; a path controller for selectively activating the despreading units; an antenna-waiting signal generator for creating an antenna-waiting signal using the pilot signals output from the despreading units; an adder for summing the data signals output from the despreading units; and a controller to control the path controller and the adder in accordance with a transmission scheme of a base station.
In one embodiment, the despreading unit comprises a pilot integrator for synthesizing the pilot signals by despreading transmission signals with the pilot Walsh code; a data integrator for synthesizing the data signals by despreading the transmission signal with the data Walsh code; and a delay unit for delaying the transmission signal, which is applied to the pilot and data integrators, for a predetermined time.
The data integrator outputs the data signal by multiplying the pilot signal by a despreading result of the transmission signal with the data Walsh code.
Each of the despreading units can further include a path estimator for evaluating a phase and a gain of the pilot signal generated from the pilot integrator. Also, the antenna-waiting signal generator can output the antenna-waiting signal using an output of the path estimator.
The despreading units are preferably to be composed of two in number.
In applying the invention to a diversity mode, the despreading units are controlled to regenerate the data signals by means of data Walsh codes, which are the same with each other and are twice the length of those for a single antenna. The path controller is controlled to enable all the despreading units, and the adder is controlled to alternately output the data signals regenerated from the despreading units.
In applying the invention to another diversity mode, the despreading units are controlled to regenerate data signals by means of data Walsh codes, which are the same with each other and are the same length as those for a single antenna. The path controller controlled to alternately enable the despreading units in accordance with a predetermined pattern, and the adder is controlled to output data signals regenerated by one of the despreading units, in series, which is selected in accordance with the predetermined pattern.
In applying the invention to still another diversity mode, the despreading units are controlled to regenerate data signals by means of data Walsh codes, which are the same with each other and are the same length those for a single antenna. The path controller enables all the despreading units, and the adder sums data signals regenerated by the despreading units.
As a result, the present invention provides a terminal-specific receiver adaptable to various environments of base station transmission diversity such as OTD, TSTD, STD, TXAA, or so on.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects, features and advantages of the invention will be apparent from the more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.
FIG. 1 is a diagram illustrating a configuration of a receiver for a terminal according to the invention.
FIGS. 2A and 2B are diagrams illustrating configurations of an OTD transmitter and receiver, respectively.
FIGS. 3A and 3B are diagrams illustrating configurations of a TSTD transmitter and receiver, respectively.
FIGS. 4A and 4B are diagrams illustrating configurations of an STD transmitter and receiver, respectively.
FIGS. 5A and 5B are diagrams illustrating configurations of a TAAA transmitter and receiver, respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a configuration of a terminal-specific receiver according to an embodiment of the invention. Referring firstly to FIG. 1 , the receiver has two despreading units 1 and 3 , a path or route controller 5 , an antenna-waiting signal generator 7 , an adder 9 , and a control block (or a controller) 6 to control the functional components. The controller 6 receives information or data relating to a transmission scheme from a base station. A base station transmits signals using a different transmission scheme in each transmission diversity technique.
The despreading units, 1 and 3 , include: pilot integrators (or synthesizers), 11 and 12 , to synthesize (or integrate) pilot signals by despreading signals, which are transmitted from a base station by means of pilot Walsh codes P 1 and P 2 corresponding thereto; data integrators, 13 and 14 , to synthesize data signals by despreading the transmission signals by means of data Walsh codes T 1 and T 2 ; a delay unit 15 to delay transmission signals applied to the pilot and data integrators for a predetermined time; and multipliers 21 through 26 . The pilot Walsh code P 1 and the data Walsh code T 1 are used for regeneration of pilot and data signals in the despreading unit 1 , while the pilot Walsh code P 2 and the data Walsh code T 2 are used for regeneration of pilot and data signals in the other despreading unit 3 . The delay unit 15 is provided to offset routing skews between antennas of the base station. The present embodiment utilizes the delay unit 15 only in the despreading unit 3 , as shown.
The data Walsh codes, T 1 and T 2 , are dependent on a kind of diversity mode. For instance, in the case in which the terminal-specific receiver is associated with OTD, T 1 and T 2 are not equal and the controller 6 operates the despreading units, 1 and 3 , to make the Walsh codes twice longer than those without diversity. On the contrary, in the conditions of TSTD, STD, and TXAA, T 1 and T 2 are identical and the length of Walsh code is the same as that with diversity.
The multipliers, 21 and 22 , regenerate pilot and data signals by multiplying a signal from the base station respectively by the pilot and data Walsh codes P 1 and T 1 . Outputs from the multipliers 21 and 22 are applied to the pilot and data integrates, 11 and 13 , respectively. Synthesized pilot and data signals in the integrators, 11 and 13 , are multiplied at the multiplier 23 . That is, a data signal restored (or regenerated) by a despreading operation with the data Walsh code is multiplied by a pilot signal restored in order to load a path characteristic on the data signal. In the despreading unit 3 , the multipliers, 24 and 25 , regenerate pilot and data signals by multiplying the signal passing through the delay unit 15 from the base station by the pilot and data Walsh codes P 2 and T 2 , respectively, which performs independent from that in the despreading unit 1 . Outputs from the multipliers 24 and 25 are applied to the pilot and data integrators, 12 and 14 , respectively. Synthesized pilot and data signals in the integrators, 12 and 14 , are multiplied at the multiplier 26 .
As shown in FIG. 1 , path or phase/gain estimators 17 and 19 are also provided in the receiver, being associated with the antenna-waiting signal generator 7 . The path estimator 17 evaluates a phase and a gain of the pilot signal generated from the pilot integrator 11 of the despreading unit 1 , and then applies a signal indicative of a path characteristic to the antenna-waiting signal generator 7 . The other path estimator 19 in the despreading unit 3 carries out the same operation as the operation of path estimator 17 on the pilot signal generated by the pilot integrator 12 . The antenna-waiting signal generator 7 checks out characteristics of transmission routes on the basis of outputs provided from the path estimators 17 and 19 , and generates control information for adjusting power rates of signals transferred from antennas corresponding thereto. The control information returns to a base station through a feedback channel, and the two antennas installed in the base station control power rates of the transmission signals. The base station controls a power of the antenna based on the control information. The control information is composed of one bit when the receiver is conductive in STD, while composed of multiple bits in TXAA. Whether the antenna-waiting signal generator 7 is active or not depends on the transmission scheme of the base station. The antenna-waiting signal generator 7 is active in the condition of STD or TXAA. The STD and TXAA transmit messages of one bit and multiple bits, respectively, to a base station through the feedback channel.
The path controller 5 alternately activates the two despreading units, 1 and 3 , in accordance with a present diversity condition. For example, the despreading units 1 and 3 are all active in OTD or TXAA. On the other hand, an alternate one of the despreading units is conductive in accordance with an intrinsic pattern associating antennas at a base station in TSTD, or in accordance with an antenna selection message in STD. Such an operation with the path controller 5 is regulated by the controller 6 .
The adder 9 , for summing data signals generated from the despreading units in response to the controller, conducts a summing operation with the data signals in accordance with a present diversity condition. First, in OTD, data signals from the despreading units 1 and 3 are alternately rearranged and output from the adder. In TSTD or STD, a data signal from a selected one of the despreading units is just turned out of the adder. In TXAA, the adder generates a sum of data signals provided from the despreading units 1 and 3 .
Assuming that a length of the Walsh code in the case without the diversity techniques is N (N is a positive integer), the receiver of the invention conducts in the unit of N chips (or bits). In FIG. 1 , it is preferably designed for the pilot and data integrators, 11 and 13 , to receive a signal from one of the two antennas installed at the base station while for the pilot and data integrators, 12 and 14 , to receive a signal from the other one of the two antennas. The reverse can also occur. The signals from the transmission antennas are demodulated, each being regarded as an independent one. That is, the pairs of the pilot and data integrators receive their own signals with independent pilots, and the signals each maintain their specific timing by means of independent time-tracking.
Operational features specified with the diversity modes are summarized in Table I below.
TABLE I
Walsh
T1, T2
Path Controller
Adder
OTD
T1 ≠ T2
All Spreading units Active
Alternate Output
Length = 2N
TSTD
T1 = T2
Selected Spreading Unit
Data Signal of
Length = N
Active
Selected
Spreading Unit
STD
T1 = T2
Selected Spreading Unit
Data signal
Length = N
Active
Selected
Spreading Unit
TXAA
T1 = T2
All Spreading Unit Active
Output After
Length = N
Summing
Operations of receivers in accordance with the diversity modes will now be described.
FIGS. 2A and 2B show functional configurations of a transmitter and a receiver, respectively, which are associated with OTD. OTD transmits signals, which are divided into two different bit streams of the channel-coded and interleaved, through individual antennas at the same time. Therefore, two antennas AT 1 and AT 2 are always in use. Independent Walsh spreading codes are each assigned to the bit streams so as to render orthogonality on the bit streams. In FIG. 2A , one of the two bit streams is composed of multipliers 32 and 33 , and a filtering/modulation (F/M) unit 36 , and the other one is composed of multipliers 34 and 35 , and filtering/modulation unit 37 . A multiplexer (MUX) generates two types of signal: one is transmitted from the antenna AT 1 after being multiplied by the pilot and data Walsh codes, P 1 and T 1 on one of the bit streams; the other is transmitted from the antenna AT 2 after being multiplied by the pilot and data Walsh codes, P 2 and T 2 on the other bit stream. The bit streams can be more segmented into larger numbers, e.g., three or four. Once a common pilot is applied to one of the antennas, e.g., AT 1 , the other antenna, e.g., AT 2 , cooperates with an auxiliary pilot. Assuming that the length of Walsh code is N, the length of the Walsh codes T 1 and T 2 becomes 2N in FIG. 2A .
In the OTD receiver shown in FIG. 2B , symbol data signals that are individually demodulated through the segmented bit streams are arranged in a demultiplexer (DEMUX) 49 , and an output of the demultiplexer 49 is applied to a combiner. At this time, the length of the data Walsh codes T 1 and T 2 is 2N.
In applying the present receiver of the invention, shown in FIG. 1 , into the OTD mode, the two despreading units 1 and 3 are controlled to regenerate data signals by means of data Walsh codes, which are different from each other, with the length of 2N that is twice that with a single antenna. The path controller 5 enables all the despreading units 1 and 3 , and the adder 9 alternately outputs the data signals regenerated from the despreading units 1 and 3 . Such a control mechanism by controller 6 makes the receiver of FIG. 1 operable in the OTD mode.
FIGS. 3A and 3B show configurations of a transmitter and a receiver, respectively, in the TSTD mode. In the TSTD mode, only one of antennas AT 3 and AT 4 is usable, although with the same Walsh codes thereon. As in the OTD mode, when a common pilot, e.g., P 1 , is associated with one of the antennas, the other antenna is associated with an auxiliary pilot. Assuming that a length of a Walsh code is N at a non-diversity mode, the length of a data Walsh code T in FIG. 3A becomes N. A switch SW 1 permits users to alternate between the two antennas by means of irregular specific patterns. The irregular specific patterns shall be designed to secure half users on an average to use a single antenna.
The receiver shown in FIG. 3B employs the same data Walsh code T with the length of N. Switches SW 2 and SW 3 allow users to alternate between the two antennas by means of irregular specific patterns. The irregular specific patterns are preliminarily provided into a mobile station by information exchange with the base station.
In applying the present receiver of the invention, shown in FIG. 1 , into the TSTD mode, the two despreading units 1 and 3 are controlled to regenerate data signals by means of data Walsh codes, which are the same from each other, with the length of N that is identical to that with a single antenna. The path controller 5 enables all the despreading units 1 and 3 in accordance with specific patterns that are used in selecting the antennas at the base station, and the adder 9 outputs a data signal of a selected one of the despreading units 1 and 3 . Such a control mechanism by controller 6 makes the receiver of FIG. 1 operable in the TSTD mode.
FIGS. 4A and 4B show configurations of a transmitter and a receiver, respectively, in the STD mode. The STD is proposed to enhance a function of the TSTD that is short of obtaining the best condition of SNR (signal-to-noise ratio) all the time at a receiver of a terminal. With an ideal case, the best performance of a receiver can be present if an antenna with the maximal SNR of reception at a terminal is selected by means of a switch SW 4 . However, it is practically impossible because there is no way to detect a status of a mobile communication channel at a base station. Since there is a feedback channel from a terminal to a base station, it is available to enhance an operational function with displaying an antenna, which is the one securing a higher SNR, on a terminal. At this time, the terminal offers antenna information to the base station by means of a one-bit antenna selection message, considering a channel capacity of a forward link. A speed in selecting an antenna heavily influences STD performance.
In FIG. 4B , the length of a data Walsh code T is N. Switches SW 5 and SW 6 are operable in accordance with an antenna selection message that is transferred to the base station from an antenna selector 80 . The antenna selection message is conductive, not directly applied to the switches, after round-trip delays and processing times in the base station and terminal.
In applying the present receiver of the invention, shown in FIG. 1 , into the STD mode, the two despreading units 1 and 3 are controlled to regenerate data signals by means of data Walsh codes, which are the same from each other, with the length of N that is identical to that with a single antenna. The path controller 5 selects the despreading units 1 and 3 in accordance with the antenna selection message. The adder 9 outputs a data signal of a selected one of the despreading units 1 and 3 . Such a control mechanism by controller 6 makes the receiver of FIG. 1 operable in the STD mode.
FIGS. 5A and 5B show configurations of a transmitter and a receiver, respectively, of the TXAA mode. The TXAA mode transmits the same data signals through two antennas, AT 7 and AT 8 , by means of the same Walsh codes. There occurs a waiting step with antenna information that arrives through a feedback channel from a terminal before the transmission. Assuming that the length of Walsh code without diversity is N, a data Walsh code T of FIG. 5A has the length of N. The values of H1(t) and H2(t) are established by the antenna-waiting signal transmitted from a terminal through the feedback channel. The values of H1(t) and H2(t) adjust phases and gains of signals transmitted through the antennas to be the maximal SNR.
In FIG. 5B , as the same data signals are transmitted through the two antennas, AT 7 and AT 8 , with the same Walsh codes, the TXAA receiver sums the two-way results at an adder 100 and then the summed result is applied to a combiner.
In applying the present receiver of the invention, shown in FIG. 1 , into the TXAA mode, the two despreading units 1 and 3 are controlled to regenerate data signals by means of data Walsh codes, which are the same from each other, with the length of N that is identical to that with a single antenna. The path controller 5 enables all the despreading units 1 and 3 , and the adder 9 sums data signals regenerated by the despreading units 1 and 3 . Such a control mechanism by 6 controller makes the receiver of FIG. 1 operable in the TXAA mode.
As described above, the present invention provides one receiver system for a mobile terminal to be adaptable to various environments of transmission diversity with base stations, such as OTD, TSTD, STD, or TXAA.
While this invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. | A device for restoring data from signals transmitted through plural antenna includes a plurality of despreading units to restore pilot and data signals by means of pilot and data Walsh codes, a path controller to selectively activate the despreading units, an antenna-waiting signal generator to generate an antenna-waiting signal with the pilot signals output from the despreading units, an adder to sum the data signals output from the despreading units, and a controller to control the path controller and the adder in accordance with a transmission scheme of a base station. The invention provides one receiver system for a mobile terminal to be adaptable to various environments of transmission diversity with base stations, such as orthogonal transmission diversity (OTD), time-switched transmission diversity (TSTD), selection diversity (STD), or transmission antenna array (TXAA). | 7 |
This application con't of U.S. patent application Ser. No. 09/872,266, (now issued U.S. Pat. No. 6,446,800), having a filing date of Jun. 1, 2001 which con't of 09/311,678 of now issued U.S. Pat. No. 6,241,086 having a filing date of May 12, 1999 which claimed priority of U.S. Provisional Patent Application Serial No. 60/091,977, having a filing date of Jul. 7, 1998, each application being incorporated herein in their entirety by reference.
FIELD OF THE INVENTION
This invention relates to sleeves for holding recording discs, and more specifically digital video discs and their accompanying graphics.
BACKGROUND OF THE INVENTION
Compact discs, or “CD”'s as they are commonly called, carry digital information such as sound and music recordings and more recently movies and video games with accompanying sound known as Digital Video Discs (hereinafter collectively “DVDs”). The DVDs replace popular video cassettes which are typically played on video cassette recorders (VCRs), and more commonly may be played on personal computers.
DVDs are generally sold to consumers in “jewel boxes” which are rigid plastic containers which carry both the DVD and accompanying graphics which identify the particular movie, video game or program contained on the DVD. The jewel boxes are bulky, difficult to store and are not conveniently opened or closed to remove the DVD. Furthermore, the graphics sold in association with the DVDs are oversized and generally resemble the size and shape of video cassettes as apposed to the width and length of the DVD. That is, the graphics are generally much longer than the DVD and additionally slightly wider. Thus, storing the DVD in a form of flexible, lightweight storage sleeve and the corresponding graphics in a sleeve with equal sized pockets is problematic.
Although lightweight, flexible storage sleeves which are designed specifically for CD's are known in the art, these devices are not designed to hold the larger graphics sold in association with DVDS. Further, if a sleeve is manufactured which is compatible in length and width for the DVD graphics, the DVD pocket which is designed for holding the DVD will generally be oversized and not overly useful.
Thus, a lightweight, flexible storage sleeve for storing DVDs is needed which can additionally store the oversized graphics associated with the DVD in a similarly sized pocket. Further, the manufacturing of the DVD sleeve must be consistent with generally recognized sleeve manufacturing processes to maintain the low cost benefits associated with flexible storage sleeves as opposed to rigid plastic jewel boxes.
SUMMARY OF THE INVENTION
It is thus an object of the present invention to provide a lightweight, flexible sleeve to store DVDs and the accompanying oversized graphics in pockets with substantially similar widths. Thus, in one embodiment of the present invention a sleeve is provided which is comprised of a front layer, an intermediate middle layer and a back layer. A pocket is provided between the front layer and middle layer for receiving a DVD while a second pocket is provided between the middle layer and back layer to receive the graphics.
It is a further aspect of the present invention to provide a cost effective, non-woven material which is in contact with the DVD which prevents scratching, does not accumulate grit or other particles and which is firm enough not to require a backing sheet for support. In one aspect of the present invention a non-woven material known as “Veratec®” is provided to serve this purpose.
It is another aspect of the present invention to provide a DVD and accompanying graphics storage sleeve which has a storage pocket for the DVD and which has a “DVD stop seal” which allows the DVD to be stored at an elevated height, thus permitting the top edge of the DVD to be near the access opening of the DVD storage pocket for easy access. The stop seal prevents the DVD from falling into the DVD storage pocket and inhibiting removal.
In one embodiment of the present invention, the stop seal is provided by utilizing a back sheet with a back sheet aperture in conjunction with a conventional manufacturing process to minimize expenses during manufacturing. Alternatively, the sleeve with a stop seal may be manufactured without utilizing a back sheet aperture.
In another aspect of the present invention, the same technology which provides the DVD stop seal in the DVD storage pocket is utilized to provide one or more “frictional nubs” to be provided in the DVD storage pocket. The “frictional nubs” prevent the DVD from falling out of the DVD storage pocket when the sleeve is turned upside down. For example, in one embodiment of the present invention the DVD storage pocket may utilize a top layer which is approximately the length of the DVD and which has a “thumb cut” or notch to allow access to the aperture of the DVD with a user's fingers or thumb. in this embodiment, there is no flap which overlays the DVD. Since the storage pocket has a diameter which is slightly larger than the DVD (as a result of the oversized graphics pocket), the DVD falls from the pocket when the sleeve is turned upside down.
To alleviate this problem, the frictional nubs engage the side edges of the DVD and prevent the DVD from inadvertently falling out of the DVD pocket. In one embodiment of the present invention the frictional nubs are provided by the sealing of the front sheet and middle sheet at one or more predetermined locations to create a DVD pocket diameter which is slightly larger than the diameter of the DVD yet provides sufficient frictional resistance to prevent the DVD from inadvertently falling out. The frictional nubs may be provided during an ultrasonic or RF welding process by providing one or more apertures in the back sheet which allow the ultrasonic welding to occur at a predetermined location without welding any other portion of the front, middle or back sheet. Alternatively, the frictional nubs may be provided without utilizing back sheet apertures by utilizing a two stage manufacturing technique which first welds the front sheet and middle sheet together while creating the frictional nubs. The back sheet is then welded in a second stage to the front and middle sheets to complete the DVD sleeve.
It is another aspect of the present invention to provide a manufacturing process for producing a sleeve design for DVDs and accompanying graphics which utilizes a “cutout” portion in the back sheet to provide either the DVD stop seal or frictional nubs on the front sheet as discussed above. Thus, in one aspect of the present invention a “cutout” or aperture in the back sheet is utilized in combination with a sheet bonding process to interconnect the front sheet and middle sheet at preselected positions to either provide a DVD stop seal in one sleeve design or one or more frictional nubs in another embodiment of the invention. Alternatively, a manufacturing process is provided which does not utilize or require a back sheet aperture to create either the DVD stop seal on the functional nubs.
In another aspect of the present invention, a “write-on” title strip is provided either along the upper edge or lateral edge of the DVD sleeve which is made of a material which permits the recordation of information related to the stored DVD either in pen, ink, or pencil.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1, is a front elevation view of a DVD storage sleeve with protective flap and a binding strip adapted for inserting the storage sleeve into a 3-ring binder and including a circular shaped DVD stop seal;
FIG. 2 is a rear elevation view of the DVD storage sleeve shown in FIG. 1;
FIG. 3 is a front perspective view of the DVD storage sleeve of FIG. 1 shown with a DVD partially inserted in the DVD pocket;
FIG. 4 is a rear perspective view of the DVD storage sleeve shown in FIG. 1 with the graphics sheet partially inserted into the graphics storage pocket;
FIG. 5 is a rear elevation view of the DVD storage sleeve shown in FIG. 1, and showing an alternative embodiment of the back sheet “cut-out” aperture;
FIG. 6 is a rear perspective view of an alternative embodiment of the DVD storage sleeve, shown without a back sheet aperture and with a graphics sheet partially inserted in the graphics storage pocket;
FIG. 7 is a front elevation view of an alternative embodiment of the invention shown in FIG. 1 with a title strip positioned proximate the upper edge of the DVD graphics pocket and the elimination of the binding strip;
FIG. 8 is a rear elevation view of the sleeve shown in FIG. 7 and further identifying the write-on title strip;
FIG. 9 is a rear elevation view of a DVD storage sleeve with binding strip for interconnection to a 3-ring notebook and including a write-on title strip positioned on the binding strip;
FIG. 10 is a front perspective view of the sleeve shown in FIG. 7 with a DVD partially inserted in the DVD storage pocket;
FIG. 11 is a rear perspective view of a DVD sleeve shown with a graphics sheet partially inserted in the graphics storage pocket and showing an alternative circular shaped back sheet aperture;
FIG. 12 is a front perspective view of the sleeve shown in FIG. 11 and showing a circular shaped disc stopping seal;
FIG. 13 is a front elevation view of an alternative DVD sleeve design which utilizes a thumb cut as opposed to a flap and showing two frictional nubs positioned proximate to the lateral edges of the DVD pocket;
FIG. 14 is a rear elevation view of the sleeve shown in FIG. 13;
FIG. 15 is a front elevation view of an alternative embodiment of the present invention showing a foldable sleeve capable of holding two DVDs and the accompanying graphics;
FIG. 16 is a rear elevation view of the sleeve design shown in FIG. 13;
FIG. 17 is a front elevation view of an alternative sleeve design with a write-on title strip which is capable of holding either one or two DVDS;
FIG. 18 is a rear elevation view of one embodiment of the sleeve shown in FIG. 17 and adapted for holding a graphics page;
FIG. 19 is a front elevation view of an alternative embodiment of the present invention where the DVD stop seal has the geometric configuration of a straight line; and
FIG. 20 is a rear perspective view of the embodiment shown in FIG. 19 .
FIG. 21 is a front elevation view of an alternative embodiment of the present invention wherein the DVD stop seal has the geometric configuration of a triangle;
FIG. 22 is a front elevation view of an alternative embodiment of the present invention wherein the DVD stop seal has the geometric configuration of a rectangle.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, FIG. 1 is a front elevation view of a first embodiment of the present invention. More specifically, the drawing shows a front elevation view of a DVD storage sleeve 2 capable of holding one DVD disc 4 and the associated graphics 26 .
The DVD sleeve 2 is generally comprised of a front or top sheet 6 , a middle sheet 18 and a back sheet 20 . A DVD pocket 22 or sleeve capable of holding a DVD is formed between the front sheet 6 and middle sheet 18 while a second graphics pocket 24 or sleeve is formed between the middle sheet 18 and back sheet 20 for holding the graphics 22 associated with the DVD FIG. 2 depicts a rear elevation view of the embodiment shown in FIG. 1 .
In one aspect of the present invention, both the front sheet 6 and middle sheet 18 are comprised of a spun-bonded, non-woven material to prevent scratching of the DVD. In an alternative embodiment, a non-woven material such as Veratece is provided. Alternatively, woven materials or other non-woven materials such as Sontara® can be used with or without any type of reinforced backing sheet made of polypropylene or other similar materials. The back sheet 20 is preferably a transparent polypropylene material which enables the user to clearly see the graphics positioned in the graphics storage pocket. Alternatively, any other type of transparent material may be used as appreciated by one skilled in the art. Various embodiments of the present invention sleeve design which have a configuration for storing two DVD's and not the accompanying graphics would preferably use non-woven materials for the front sheet 6 , middle sheet 18 and back sheet 20 .
Since the DVD graphics 26 are both slightly wider and substantially longer than the diameter of the DVD 4 which is stored in the opposing DVD storage pocket, modifications must be made to the DVD storage pocket to facilitate access to the DVD 4 and/or prevent the DVD from falling out of the storage sleeve if the sleeve is inverted. In the embodiments shown in FIGS. 1-10, a flap 14 is provided in the front sheet to cover the DVD to prevent dust and other foreign materials from entering the pocket. Further, the flap prevents the DVD from falling out of the pocket inadvertently if the sleeve is inverted. In one embodiment, the flap has an arcuate shape at the point of termination to resist tearing when the flap is repeatedly opened and closed.
Since the DVD 4 has a diameter (and hence length) which is significantly less than the DVD graphics sheet 26 , the overall DVD pocket 22 length must be substantially reduced to prevent the DVD 4 from falling into the pocket an excessive distance. Thus, a DVD “stop seal” 28 is provided and positioned approximately the diameter of a DVD down the length of the DVD pocket 22 from the sleeve upper edge 8 to hold the DVD 4 at an elevation which allows removal of the DVD 4 when the flap 14 is lifted upward. Preferably the DVD stop seal 28 is positioned at a location which places a top edge of the DVD near the hinge position of the flap 14 .
The DVD stop seal 28 is created by interconnecting the flexible front sheet 6 to the middle sheet 18 at a predetermined location, yet not interconnecting the middle sheet 18 to the flexible back sheet 20 and hence reducing the size of the graphics pocket 24 . The interconnection may be accomplished by individually sewing, heat bonding or otherwise interconnecting the front sheet 6 and middle sheet 18 prior to interconnecting the back layer. Preferably, the front sheet 6 is first interconnected to the middle sheet 18 by welding or other similar technique while the DVD stop seal 28 or frictional nubs 36 are additionally created by interconnecting the front sheet 6 and middle sheet 18 at predetermined locations. The back sheet is then interconnected to the middle sheet 18 by welding or other similar means to complete the DVD sleeve in the two stage manufacturing process.
Alternatively, to enable the DVD stop seal 28 to be created during conventional manufacturing processes where the front sheet 6 , middle sheet 18 and back sheet 20 are simultaneously welded together, a back sheet “cutout” aperture 32 may be provided in the transparent polypropylene back sheet 20 prior to welding. Thus, as seen in FIG. 2, a circular cutout portion is provided in the polypropylene back sheet 20 which allows the front sheet 6 and middle sheets 18 to be bonded together at a position just below where the DVD rests in the DVD pocket 22 . The DVD stop seal 28 thus prevents the DVD 4 from sliding downward into the DVD pocket 22 to a position which is difficult to access from the pocket opening proximate the flap 14 .
Although in the embodiment shown in FIG. 1 and FIG. 2 the back sheet cut-out aperture 32 and corresponding DVD stop seal 28 are circular in shape, as appreciated by one skilled in the art the geometric shape and size of both the cutout aperture 32 and DVD stop seal 28 can be any variety of sizes and shape. For example, it is possible to use straight lines, arcuate lines, triangular or rectangular shapes or more than one cutout and DVD stop seal 28 as long as the cutout aperture 32 and corresponding DVD stop seal 28 serve the purpose of interconnecting the front sheet 6 and middle sheet 18 at a position which prevents the DVD from falling downward into the DVD pocket 22 .
For example, in FIGS. 5-8, an arcuate shaped cut-out aperture 32 and/or stop seal 28 is utilized as opposed to the circular cut-out aperture 32 and stop seal 28 shown in FIGS. 1-4. As discussed in greater detail below, FIG. 6 depicts a DVD sleeve which utilizes a DVD stop seal 28 , but is manufactured utilizing a procedure which does not require a back sheet aperture 32 .
Referring now to FIGS. 3-4, front and rear perspective views of the DVD storage sleeve 2 are shown with a DVD 4 being shown partially inserted into the DVD pocket 22 in FIG. 3 while FIG. 4 depicts the graphics sheet 26 being partially inserted into the graphics' storage pocket 24 . As shown in FIGS. 1-4, the DVD storage sleeve 2 in one embodiment is designed to be inserted into a 3-ring binder such as a notebook for storage purposes. This is accomplished by providing a binding strip 38 positioned proximate to one of the lateral edges 12 of the DVD and graphics storage pocket and including one or more binding apertures 30 to allow insertion into a binding device.
Furthermore, as seen in FIG. 6, a rear perspective view of the DVD sleeve 2 is shown without the back sheet aperture 32 , yet still utilizing a DVD stop seal 28 when the front sheet 6 and middle sheet 18 are interconnected. This is accomplished by utilizing a two stage manufacturing process which first welds the front sheet 6 and middle sheet 18 along the bottom edge, lateral edges and possibly the upper edge. Simultaneously, the DVD stop seal 28 on the functional nubs 36 are creating by welding the front sheet 6 and middle sheet 18 at predetermined locations to support or functionally engage the DVD. The back sheet 20 is then interconnected by welding or other similar means to the front and middle sheets along at least the lateral edge and bottom edge to complete the DVD sleeve manufacturing process.
Referring now to FIGS. 7-11, an alternative embodiment of the invention shown in FIG. 1 is provided with the binding strip 38 removed on the lateral edge of the DVD sleeve. Thus, in this embodiment the DVD sleeve cannot be used in conjunction with a 3-ring binder, but rather the DVD sleeve 2 is used in association with a tray or other similar device which allows a multiplicity of DVD sleeves 2 to be stored upright until use.
As further identified in FIGS. 7-11, in an alternative embodiment of the present invention, a title strip 34 is provided and positioned proximate to the upper edge 8 of the graphics or DVD storage pocket. The title strip 34 is comprised of any type of material which allows the recordation of information related to the DVD or graphics, such as polypropylene, vinyl, or a non-woven material with a white finish. Preferably the information can be written in pen ink, pencil, or magic marker and more preferably can be erased if necessary. Alternatively as shown in FIG. 9, the title strip maybe provided proximate a lateral edge 12 of the DVD sleeve 2 , either in conjunction with a binding strip 38 and aperture 30 or independently without the aperture 30 associated with a binding strip 38 . FIG. 10 depicts a front perspective view of a DVD sleeve 2 with a DVD 4 partially inserted into the DVD storage pocket 22 and additionally identifying the DVD stop seal 28 .
FIG. 11 is a rear perspective view of a DVD sleeve 2 shown with a graphics sheet 26 partially inserted into the graphics pocket 24 . In this figure, a substantially round back sheet aperture 32 is utilized. FIG. 12 is a front perspective view of the DVD sleeve shown in FIG. 11 .
Referring now to FIGS. 13 and 14, an alternative embodiment of the present invention is shown which does not utilize a flap 14 positioned on the front sheet 6 to hold the DVD in place. In this embodiment, the front sheet 6 utilizes a “u” shaped thumb cut 42 which extends downwardly to permit the user of the sleeve 2 to access the aperture 44 of the DVD for removal. In this embodiment, the sleeve 2 does not require a DVD stop seal 28 since the DVD pocket 22 is substantially the same length as the diameter of the DVD. However, without the flap embodiment shown in FIG. 1, it would be possible for the DVD 4 to inadvertently fall from the DVD pocket if the sleeve 2 is inverted. This is due to the fact the DVD pocket 22 is slightly larger than the DVD since the graphics pocket 24 required for the accompanying graphics 26 on the reverse side must be wider to hold the slightly larger graphics.
To alleviate the problem of the DVD inadvertently falling from the DVD pocket 22 , frictional “nubs” 36 are provided as shown in FIG. 13 to effectively reduce the diameter of the DVD pocket 22 and to engage the DVD 2 in such a manner as to prevent the DVD 2 from inadvertently falling out of the DVD 22 pocket when the DVD sleeve 2 is inverted.
To provide the frictional nubs 36 , in one embodiment back sheet “cutouts” or apertures 32 are provided in the back sheet 20 at the location immediately opposite the position on the flexible front sheet 6 and middle sheet 18 where the frictional nubs 36 are desired. The front, middle, and back sheets may then be ultrasonically welded along the top edge, bottom edge and lateral edges simultaneously during a bonding process while the middle sheet 18 and front sheet 6 are additionally bonded at the location of the frictional nubs 36 . Similar to the DVD stop seals 28 previously discussed, any number of geometric configurations and/or number of frictional nubs 36 may be utilized to achieve the function of effectively reducing the internal diameter of the DVD pocket 22 to such a degree that the DVD 2 will not fall from the DVD pocket 22 when the DVD sleeve 2 is turned upside down.
Alternatively, and as previously discussed, it is possible to create the frictional nubs 36 without utilizing a back sheet aperture 32 by utilizing a different two stage manufacturing process which first welds the front sheet 6 and middle sheet 18 while making the necessary welds for the frictional nubs 36 . The back sheet 20 is then interconnected to the first sheet 6 and middle sheet 18 by welding or interconnection method which is commonly known in the art.
As shown in FIGS. 13 and 14, in one embodiment of the present invention two frictional nubs 36 are provided at a position adjacent the lateral edges 12 of the DVD pocket 2 proximate to a location which is adjacent the widest portion of the DVD 2 when it rests in the DVD pocket. As the DVD 2 is inserted into the DVD pocket 22 , the DVD 4 engages the frictional nubs 36 and is substantially prevented from falling from the DVD pocket 22 even when the DVD sleeve 2 is inverted. For removal during normal use a user merely applies a slight finger pulling force while holding onto the DVD aperture 44 or edge.
Referring now to FIGS. 15-16, a front and back view of an alternative embodiment of the present invention is shown with dual capacity DVD storage sleeves and dual capacity graphics storage pockets 24 for storing the accompanying graphics. As shown in the front elevation view of FIG. 13, a DVD storage pocket 22 with flap 14 is shown on the left side of a foldable sleeve, while a graphics storage pocket 24 is shown on the right side. As shown on the rear elevation view of FIG. 13, a mirror image of the front view is shown with a second DVD storage pocket positioned immediately behind the first DVD storage pocket 22 and a second graphics storage pocket 24 positioned immediately behind the first graphics storage pocket 24 . In an alternative embodiment of the present design in FIGS. 13-14, the flap design shown may be replaced with a “u” shaped thumb cut as shown in the sleeve in FIGS. 11-12.
As seen in both the front and rear elevation views of FIGS. 15-16, both of the DVD storage pockets have a common DVD stop seal 28 to prevent the DVDs from falling into the pocket and thus becoming substantially inaccessible to the user. This design implementing dual DVDs storage pockets positioned immediately opposite one another also allows the dual capacity sleeve to be manufactured without requiring a “cutout” aperture 32 on the back sheet to provide a DVD stop seal 28 as previously discussed in various embodiments above.
In the embodiment shown in FIGS. 13-14, both the front sheet 6 and back sheet 20 of the graphics storage pocket 24 are comprised of a transparent material such as polypropylene to permit viewing of both graphics sheets. Preferably the front sheet 6 and back sheets 20 utilized for the DVD storage pockets 22 and the middle sheets 18 are comprised of a non-woven material to prevent any scratching of the DVDs 4 . Of course any combination of materials known in the art could be used to accomplish the same purpose of providing a flexible sleeve for the storage of DVDs and the graphics.
Referring now to the front elevation view shown in FIG. 17, an alternative embodiment of the present invention is provided which allows the storage of two DVDs 4 , yet does not provide storage for the accompanying graphics. Further, a write-on title strip 34 is provided along an upper edge of the DVD pocket 22 and flap. Alternatively, the back sheet 20 may be transparent to facilitate the storage of graphics associated with the DVD.
In another aspect of the present invention a process is provided for manufacturing the DVD sleeves shown in FIGS. 1-12 that utilize either a DVD stop seal 28 or frictional nubs 36 . This process is initiated by providing the front sheet 6 , middle sheet 18 and back sheets 20 on continuous rolls of the respective materials. The individual sheets of material with a predetermined width are then rolled out and the respective “cutouts” made to each sheet. For example, in the embodiment shown in FIG. 1, the top layer has a flap cut, while the back layer has a cutout made for the graphics thumb cut (at top of sheet) and a circular DVD pocket cutout which corresponds to the location of the DVD stop seal 28 . There are no cutouts necessary on the middle layer.
After the cutouts are made to the respective front and back sheets, the individual layers of material are all fed back together and aligned, at which time all of the weld seals of the three layers are made simultaneously. These welds include the seals required on the peripheral edges to form the pockets as well as the DVD stop seals 28 or frictional nubs 36 as the case may be. Once all of the welds have been made the continuous roll of sealed material is cut as appropriate to create the individual DVD sleeve 2 . Although the process generally described utilizes ultrasonic welding to form the necessary seals, as appreciated by one skilled in the art RF (radio frequency) welding or other forms of interconnection can be implemented to create seals between various layers of now-woven or transparent type materials such as polypropylene.
Alternatively, in a method to provide the DVD stop seals 28 on frictional nubs 36 without utilizing a back sheet aperture 32 , a two stage manufacturing process is utilized which first interconnects the front sheet 6 to the middle sheet 18 while additionally creating the DVD stop seal 28 or frictional nubs 36 . The back sheet 20 is then interconnected to the middle sheet 18 and front sheet 6 to complete the DVD sleeve 2 .
Referring now to FIGS. 19-20, an alternative embodiment of the present invention is provided herein which depicts one of the DVD stop seal 28 embodiments previously discussed. For example, the DVD stop seal 28 may have any variety of geometric shapes capable of suspending the DVD 4 in an upper portion of the DVD pocket 22 . For example, the DVD stop seal can be a straight line, arcuate line, triangular or rectangular shape. In FIG. 19, a front elevation view is provided of one embodiment where the DVD stop seal 28 is a straight line with a flap 14 . Alternatively, the flap 14 could be removed and replaced with a “u” shaped thumb cut or other embodiment which allows the DVD 4 to be grasped for removal. FIG. 20 is a rear elevation view of the sleeve shown in FIG. 19, and which further identifies a plurality of binding apertures 30 positioned along a lateral edge 12 of the sleeve 2 to permit the sleeve 2 to be stored in a binding device such as a notebook or DVD wallet.
To assist the reader in the understanding of the present invention, the following list of components and associated numbering found in the drawings are provided hereinbelow:
Number
Component
2
Sleeve
4
Digital Video Disc
6
Front sheet
8
Upper edge
10
Bottom edge
12
Lateral edge
14
Flap
16
Digital video disc front surfaces is middle sheet
18
Middle sheet
20
Back sheet
22
DVD pocket
24
Graphics pocket
26
Graphics
28
DVD Stop Seal
30
Binding Aperture
32
Back sheet aperture
34
Title strip
36
Frictional Nub
38
Binding strip
40
Thumb notch
42
Thumb cut
44
DVD aperture
The foregoing description of the present invention has been presented for purposes of illustration and description. The description is not intended to limit the invention to the form disclosed herein. Consequently, the invention and modifications commensurate with the above teachings and skill and knowledge of the relevant art are within the scope of the present invention. The preferred embodiment described above is also intended to explain the best mode known of practicing the invention and to enable others skilled in the art to utilize the invention in various embodiments and with the various modifications required by their particular applications for use of the invention. It is intended that the claims be construed to include all alternative embodiments as permitted by the prior art. | This invention relates to a sleeve for holding one or more digital video discs with a first dimension in a first pocket and the accompanying graphics having a second dimension in a second opposing pocket. The digital video disc is supported in the first pocket by one or more stop seals which elevate the digital video disc to a more accessible position for removal. | 6 |
FIELD OF THE INVENTION
The present invention is directed to binary colloidal crystals, and in particular to colloidal crystals that are stabilized by Coulombic forces.
BACKGROUND OF THE INVENTION
Monodisperse colloidal particles are recognized for their ability to form a variety of crystalline structures that are being considered for a wide range of technologies, including photonics (as photonic crystals or as pigments), catalysis, electrochemical devices (e.g., fuel cells and batteries), biomaterials, and drug delivery vehicles. Various structures have been produced using hard-sphere packing mechanisms, including face-centered cubic and body-centered cubic arrangements.
Binary colloidal crystals (ordered arrays of two particle types) have also been produced, using long-range electrostatic or steric repulsive forces (Velikov, et al., Science 296: 106, 2002), short-range attractive interactions such as DNA bridges (Soto, et al., J. Am. Chem. Soc. 2002(124):8508, 2002), or contact hard-sphere interactions (see Bartlett, et al., Phys. Rev. Lett., 68(25):3801, 1992, and Schofield, Phys. Rev. E 64:051403, 2001). While a wider variety of systems can be achieved using binary particle systems, current methods limit crystal structures to the types found in metallic systems (e.g., the CsCl structure, which is found in the Cu—Zn and Al—Ni alloy systems).
SUMMARY OF THE INVENTION
In one aspect, the invention comprises an ionic colloidal crystal (ICC). The ICC comprises an ordered array of particles, including a first group of particles of a first composition and a second group of particles of a second composition. The groups of particles have opposing surface charge, and the ordered array is stabilized primarily by Coulombic interactions between the two compositions. The ICC may have a volume of two, four, ten, fifty, or more unit cells, and may take on ionic crystal structures such as rock salt, cesium chloride, zincblende, wurtzite, fluorite, rutile, ruthenium oxide, or corundum. The particles may be substantially spherical, and each group may have a substantially uniform diameter. They may have a selected surface charge and Debye length. The particles may be coated or functionalized. The crystallite may further comprise a liquid medium, and the surface charges of the particles may be determined by the composition of the liquid medium. The particles may be nonspherical and/or may carry anisotropic surface charge. The ordered array may be additionally stabilized by van der Waals forces, depletion forces, or external directional forces.
The invention further comprises a photonic crystal comprising an ICC as described above, which may, for example, have a wurtzite or zincblende structure. The invention also comprises a self-assembled laser comprising the ICC as described above, where at least one of the groups of particles fluoresces at a selected wavelength, and the ICC has a photonic bandgap that prohibits fluorescence at that wavelength. The invention also comprises an active material comprising an ICC as described above, where at least one type of particle is electro-optic, magneto-optic, ferroelectric, ferromagnetic, electrostrictive, or magnetostrictive. The invention also comprises a nonlinear conduction device comprising an ICC as described above, where the particles of the two groups form rectifying junctions (e.g., Schottky junctions or p-n junctions). The invention also comprises a catalyst comprising an ICC as described above.
In another aspect, the invention comprises methods of preparing ICCs. One such method includes providing first and second suspensions of particles of a first and second composition in a first and second solvent, and mixing the first and second suspensions to form a mixed suspension. The first and second compositions of particles take on opposing charges in the mixed suspension. Finally, the particles are coagulated out of the mixed suspension to form an ordered array stabilized primarily by Coulombic forces. Alternatively, instead of mixing, the two suspensions may be coagulated by sequential addition of the first and second suspensions. If the suspensions are mixed, mixing may take place adjacent to the ordering site. Coagulating may include depositing particles on a surface, which may promote ordering of the formed array. The surface may include lines, gratings, ledges, steps, grids, or ordered particles. A directional force, such as a gravitational or centrifugal force, or an electric or magnetic field, may be applied during coagulation. The particles may form crystal structures such as rock salt, cesium chloride, zincblende, wurtzite, fluorite, rutile, ruthenium oxide, or corundum. The particles may be substantially spherical, and each group may have a substantially uniform diameter. They may have a selected surface charge and Debye length. The particles may be coated or functionalized. The crystallite may further comprise a liquid medium, and the surface charges of the particles may be determined by the composition of the liquid medium. The particles may be nonspherical and/or may carry anisotropic surface charge. The ordered array may be additionally stabilized by van der Waals forces, depletion forces, or external directional forces. Kinetic energy may be added to the mixed suspension during coagulation, for example by ultrasonification, fluid flow, agitation, or alternating electric or magnetic fields.
In still another aspect, the invention comprises a method of selecting materials for an ionic colloidal crystallite to obtain a desired crystal type having a selected stoichiometry. The method comprises selecting at least a first and a second particle composition, a first and a second particle radii a 1 and a 2 , and a solvent composition. Particles of the first composition suspended in the solvent have a surface potential of Ψ 1 , particles of the second composition suspended in the solvent have a surface potential of Ψ 2 , and the solvent has a reciprocal Debye length of κ. The method further comprises calculating a charge ratio Q as
- a 1 Ψ 1 exp ( κ a 1 ) a 2 Ψ 2 exp ( κ a 2 ) ,
calculating a dimensionless length Λ as κ(a 1 +a 2 ), calculating an ionic radius ratio r as
a 1 a 2 ,
and using Pauling's Rules and r to determine favored crystal structure types. The method further comprises calculating the Madelung constant for each favored crystal type having a stoichiometry matching the selected stoichiometry, determining the stable phase as the favored crystal type having the highest Madelung constant, and adjusting the selected first and second particle compositions, first and second particle sizes, and solvent compositions until the stable phase matches the desired crystal type.
BRIEF DESCRIPTION OF THE DRAWING
The invention is described with reference to the several figures of the drawing, in which,
FIG. 1 shows the Madelung constant for the rock salt structure as a function of the dimensionless charge ratio (Q) and the dimensionless length (Λ);
FIG. 2 shows the converging values of the Madelung sum for Q=1 in a rock salt structure;
FIG. 3 is a phase diagram showing stability fields for five ICC structure types as a function of Q and Λ;
FIG. 4 superimposes Q(Λ) functions for three selected material systems onto the phase diagram of FIG. 3 ;
FIGS. 5 a -5 c are micrographs of crystallites of rock salt structure formed in an ICC;
FIGS. 6 a and 6 b each show three views of a simulated ICC grown under an applied gravitational force; and
FIG. 7 shows a disordered heterocoagulate structure.
DEFINITIONS
As used herein, a “crystal” or “crystallite” is an ordered array structure formed by arrangement of particles or atoms on a crystal lattice. An ordered arrangement of particles is considered to form a crystal or crystallite if it includes an ordered region having a volume equivalent to at least one unit cell of the crystal structure.
As used herein, “depletion forces” are osmotic pressures arising when molecules or particulates in suspension, typically of much smaller size than the colloidal particles being aggregated, are depleted from the constrained volume between particles for entropic reasons, thereby adding an additional attractive force tending to bring the colloidal particles together.
As used herein, “van der Waals forces” includes all weak intermolecular forces, including without limitation London dispersion forces, Keesom forces, Debye forces, and Casimir forces.
As used herein, “gravitational forces” includes all externally applied directional forces, including inertial forces such as centrifugal force.
As used herein, a “functionalized” particle is one that has an organic or inorganic chemical bonded to its surface, where the free end of the chemical has a desired radical or structure.
As used herein, “Pauling's Rules” refer to the relationship between the ratio of ionic radii and crystal structure of ionic crystals:
ratio of ionic radii
coordination number
Crystal type
1.0-0.732
8
Cubic
0.732-0.414
6
Octahedral
0.414-0.225
4
Tetrahedral
0.225-0.155
3
Triangular
<0.155
2
Linear
DETAILED DESCRIPTION
Colloidal crystals, or ordered arrays of particles, can be synthesized and, like naturally occurring silica-based colloidal crystals such as opal, possess physical properties that derive from their mesostructure. Most colloidal crystals are based on the ordered packing of a single, typically spherical, particle type. We have found that electrostatic stabilization concepts from classical ionic crystal chemistry can be extended to the mesocopic scale to produce self-organizing, binary “ionic” colloidal crystals. We have shown analytically and experimentally that a binary colloidal suspension containing oppositely-charged particles can lower its electrostatic energy by ordering in various ionic crystal structure-types. The capability for synthesizing entirely new classes of colloidal crystals is expected to find applications in a broad range of fields including photonics, catalysis, pharmaceuticals, and ferroic materials.
To our knowledge, multicomponent colloidal crystals produced using long-range attractive Coulombic forces have not been produced. Heterocoagulation, or the coagulation of dissimilar particles through attractive Coulombic forces, typically results in a low packing density noncrystalline structure such as that obtained during reaction-limited cluster aggregation (RLCA) or diffusion-limited cluster aggregation (DLCA) (see, e.g., Kim, et al., J. Colloid and Interf. Sci. 229:607, 2000; Fenandez-Nieves, et al., Phys. Rev. E 6405:51603, 2001; AlSunaidi, et al., Phys. Rev. E 61:550, 2000). In these cases, the structures exhibit no long-range order because the large interparticle binding energy relative to the thermal energy in such systems resists structural rearrangement. We have identified conditions under which heterocoagulation into ionic colloidal crystals (ICCs) is energetically favored over primary heterocoagulates (such as isolated dipolar particle pairs). A dimensionless length, A, characterizing the spatial range of the electrostatic interaction, and a ratio of particle effective charges, Q, are used to characterize a parameter space in which ICC formation is energetically favorable. We have found that the conditions required for ordered heterocoagulation are quite restrictive, possibly explaining why ICCs have not been reported previously. An experimental system satisfying these conditions has been created and used to demonstrate ionic colloidal crystallization of two dissimilar sphere types into the rock salt structure.
Interparticle Potential
The formation energy of an ionic colloidal crystal can be calculated from the sum of all interactions between similar and dissimilar particles. The theory of Derjaguin, Landau (Derjaguin, et al., Acta physicochimica 14:633, 1941, incorporated by reference herein), Verwey, and Overbeek (Verwey, et al., Theory of the stability of lyophobic colloids , Elsevier Pub. Co., New York, 1948, incorporated by reference herein) (“DLVO” theory) is commonly applied to the homocoagulation of similar colloidal particles. However, for dissimilar particles, the theory must be modified to account for the differences in particle size, and the sign and magnitude of the surface charge. The theory of Hogg, Healy, and Fuerstenau (HHF) (Hogg, et al., Trans. Faraday Soc. 62:1638, 1966, incorporated by reference herein) extends the DLVO theory to heterocoagulated systems. Inherent in HHF theory are several approximations including the linearization of the Poisson-Boltzmann equation (PBE) and the Derjaguin approximation (Derjaguin, Kolloid Z. 69:155, 1934, incorporated by reference herein).
Under the linear PBE, which is a good approximation when the surface potential is small (see Islam, et al., Adv. in Colloid and Interf. Sci. 62:109, 1995), the potential fields from neighboring particles can be superimposed. However, under the nonlinear PBE the total electrostatic energy cannot be determined through the pairwise summation of the interaction energies of all particles, but instead requires the numerical calculation of the energy for each specific arrangement of particles. In our analysis, we assume the linear PBE to be valid. However, we do not use the Derjaguin approximation, for the following reasons. In the limit of very small salt concentration, the HHF potential falls off more slowly than the 1/r dependence seen in an unshielded electrostatic system. This behavior is unphysical and is a direct result of the Derjaguin approximation where the spheres are treated as a superposition of flat plates, which would interact with a constant potential field were no shielding present. Futherermore, the HHF potential diverges as two spheres with opposite signs of surface charge come into contact.
Thus, we have developed a theory with broader applicability than HHF, starting from the linearized Poisson-Boltzmann equation:
∇ 2 ψ = κ 2 ψ - ρ ɛ 0 ɛ r ( 1 )
Here ψ is the electrostatic potential field, κ is the Debye parameter, and ρ is the spatial distribution of fixed charges in the system (i.e., on particle surfaces). This equation has a Green's function solution that is of Yukawa-type:
G ( R -> - R ′ -> ) = Q 4 πɛ 0 ɛ r exp ( - κ R -> - R ′ -> ) R -> - R ′ -> ( 2 )
Here Q is the magnitude of the point charge, R is a vector of an arbitrary origin, and R′ is the vector position of the charge center from that origin.
It is assumed that the spatial distribution of charge remains fixed throughout. This assumption, corresponding to a constant surface charge on the particles, is one of two commonly used surface boundary conditions in colloids, the other being the assumption of a constant surface potential. A constant surface potential boundary condition is unphysical, since two touching spheres with different surface potentials have a divergent electric field at the point of contact, resulting in an unbounded total energy. In contrast, the internal energy of two particles with constant surface charge density is finite everywhere.
Integration of the Green's function over a sphere of radius a 1 with a uniform charge density yields a spatially-varying potential that is identical to that of a point charge of magnitude Ψ 1 a 1 exp(κa 1 ), where Ψ 1 is the surface potential of the particle, and r is the distance from the center of the particle:
ψ
(
r
)
=
a
1
Ψ
1
exp
(
κ
a
1
)
exp
(
-
κ
r
)
r
(
3
)
The solution in (3) only applies outside of the charged particle. In the case of an isolated particle, this is identical to a sphere with a constant surface potential of Ψ 1 . This constant surface potential can be used to determine the surface charge for an isolated particle. As in previous theories, the potential need not be fixed at the physical surface of the particle, but can be fixed at any shell of constant potential. In the case of the Stern approximation, the surface potential is replaced by the zeta potential, making the surface charge an effective charge equal to the difference between the bound surface charges and the trapped counterions in the Stern layer.
Using Equation (3), the interaction energy of two particles separated by a distance r is the product of the potential field of one particle and the charge of the other, evaluated at the separation distance:
U
(
r
)
=
4
πɛ
0
ɛ
r
a
1
a
2
Ψ
1
Ψ
2
exp
(
κ
a
1
+
κ
a
2
)
exp
(
-
κ
r
)
r
(
4
)
The interaction energy for homocoagulation has also been calculated by an alternative method that results in a Yukawa-type potential.
U ( r ) = Z 2 ⅇ 2 4 πɛ 0 ɛ r [ exp ( κ a ) 1 + κ a ] 2 exp ( - κ r ) r ( 5 )
where a is the radii of the particles and Z is the amount of charge on the particle surface. In this method, the surface charge is set to the value of all counterions in solution above the equilibrium concentration, effectively imposing a zero net system charge constraint. This method yields results identical to ours for an isolated particle. However, to our knowledge, a Yukawa-type potential has not been applied to heterocoagulation.
The relation between surface charge and surface potential for an isolated particle is:
Ψ
surf
=
Z
surf
e
4
πɛ
0
ɛ
r
(
1
+
κ
a
)
a
(
6
)
Using (4), we obtain the correct 1/r dependence of the potential field in the limit of zero Debye parameter (no shielding ions), while allowing the energy to remain bounded at particle contact (r=a 1 +a 2 ). This allows the calculation of the interaction energy for a system of contacting charged spheres, whether they are of like or opposite charge.
Madelung Constants for Ionic Colloidal Crystals
The Madelung constant of an ionic crystal, used as a measure of crystalline stability, is the idealized electrostatic energy of the crystalline array relative to that of the same number of atoms present as isolated molecules. In the case of ICCs, we likewise use a Madelung sum to compare the electrostatic energy of various structure types to an equal number of isolated particle arrangements, and to each other. Two key distinctions between colloidal and classical ionic crystals are noted. In ionic crystals, ion sizes and valences are limited to those available in the Periodic Table, while for colloidal crystals, the particle size and surface charge can be continuously varied, to some extent independently. In conventional ionic crystals, charge neutrality is solely provided by the ions of opposite charge, while in colloidal systems, the counterion space-charge cloud provides an additional charge-compensation mechanism. The impact of these fundamental differences can be seen in the following results.
The classical Madelung sum, which converges weakly without the use of special techniques, is a summation of the electrostatic interactions between one ion and all other ions in a crystal. For a binary compound, this is:
U = 1 4 πɛ 0 ɛ r ( N 1 Q 1 Q 2 r 1 + N 2 Q 1 Q 1 r 2 + N 3 Q 1 Q 2 r 3 + … ) ( 7 )
where N i is the number of identical ions at distance r i and Q j is the absolute value of charge of the j th particle. As an example, for the rock salt structure type this energy is:
U = e 2 4 πɛ 0 ɛ r ( - 6 r 0 + 8 2 r 0 - 12 3 r 0 + … ) ( 8 )
where r 0 is the interionic separation. Upon normalizing this energy by the Coulombic energy of an isolated particle pair at the equilibrium separation, the Madelung constant is obtained:
α
=
6
-
8
2
+
12
3
+
…
=
1.748
(
9
)
In the case of ionic colloidal crystals, we substitute the Yukawa type potential in (4) for the simple Coulombic interaction. The potential still includes two charges (Q i ) and an 1/r dependence, but there is now an exponential decay to account for counterion shielding in the solution. The potential energy summation for a binary ICC structure is, in the general case:
U
=
1
4
πɛ
r
ɛ
0
(
N
1
Q
1
Q
2
exp
(
-
κ
r
1
)
r
1
+
N
2
Q
1
Q
1
exp
(
-
κ
r
2
)
r
2
+
N
3
Q
1
Q
2
exp
(
-
κ
r
3
)
r
3
+
…
)
(
10
)
This equation reduces to (7) as the inverse Debye length κ goes to zero, making the ICC formulation and the Coulombic formulation identical in this limit of no counterion shielding. Note that the oppositely charged particles do not necessarily have equal magnitude of charge. The summation is then normalized by the energy of an isolated pair (for a crystal of 1:1 particle ratio) to obtain the Madelung constant:
α
=
N
1
+
N
2
Q
1
Q
2
r
1
r
2
exp
(
κ
r
1
-
κ
r
2
)
+
N
3
r
1
r
3
exp
(
κ
r
1
-
κ
r
3
)
+
…
(
11
)
This result explicitly includes the particle effective charges and the Debye length (κ −1 ). We next introduce two dimensionless parameters, each with a clear physical significance:
Q
=
-
Q
1
Q
2
=
-
a
1
Ψ
1
exp
(
κ
a
1
)
a
2
Ψ
2
exp
(
κ
a
2
)
(
12
)
Λ
=
κ
r
1
=
κ
(
a
1
+
a
2
)
(
13
)
Q is the ratio of the effective charges, which are the point charge equivalents of the colloidal particles, directly analogous to the effective valence of ions. The dimensionless length, Λ, is the Debye length normalized to the sum of the particle radii, and gives the spatial extent of the potential with respect to the interparticle separation. Here particles 1 and 2 are chosen so that the ratio Q has a value greater than one. The Madelung sum now depends only on these two dimensionless parameters and the spatial arrangement of particles:
α = N 1 - N 2 Q 1 c 2 exp ( Λ - Λ c 2 ) + N 3 1 c 3 exp ( Λ - Λ c 3 ) + … ( 14 )
Here c i is the ratio of the i th distance to the sum of particle radii (a 1 +a 2 ), and N i is the number of identical particles at the distance r i . For any structure type, the ICC Madelung constant can be calculated as a function of the two dimensionless parameters. Applying (14) to the rock salt structure type as an example, the first terms of the Madelung sum are:
α
=
6
-
12
Q
1
2
exp
(
Λ
-
Λ
2
)
+
8
1
3
exp
(
Λ
-
Λ
3
)
+
…
(
15
)
FIG. 1 shows the Madelung constant for the rock salt structure as a function of the dimensionless charge ratio (Q) and the dimensionless length (Λ). Where α is greater than 1, the ICC is energetically favorable compared to a system of isolated particle pairs. At high values of Λ, the Madelung constant approaches 6, corresponding to nearest-neighbor attraction alone. At lower values of Λ, next-nearest-neighbor repulsion becomes more significant, allowing long-range ordering to be energetically favorable. The regions shown in solid blue have a Madelung constant below 1 and are not stable. The figure is reciprocally symmetric about Q=1.
FIG. 2 shows the converging values of the Madelung sum for Q=1 in a rock salt structure as Λ approaches zero. The calculation for the Madelung sum failed to converge below Λ=0.06 for our calculations. A linear extrapolation found a value of α=1.7471 at Λ=0; the accepted numeric ionic crystal value is 1.748.
Note in FIG. 1 that at a charge ratio of Q=1, and a 1:1 particle stoichiometry, the two types of particles can charge-compensate one another without requiring a contribution from the counterions. No net motion of counterions in the solution is required to make the structure electrically neutral. These conditions yield the largest Madelung sum, for any value of Λ. Note also that at large values of Λ (small Debye length) the Madelung constant approaches the value 6 for all charge ratios. This is due to the screening of all but the 6 first-nearest-neighbors in the rock salt structure type. (The energy difference between disordered and ordered structures is not explicitly shown in FIGS. 1 and 2 .)
Phase Diagram Representation
The stability of various ICC structures that can in principle crystallize from a single binary suspension can be compared using a phase diagram with Q and Λ as the axes, as shown in FIG. 3 . In this diagram, each field represents the structure having the highest Madelung constant at the given values of the dimensionless parameters. (Other structures can still be energetically stable.) The diagram is reciprocally symmetric about Q=1, however the size ratio limitations change. For example, CaF 2 has the highest charged ion in an octahedral site and the other in a tetrahedral site. The size ratio of the ions must allow the proper ion to sit in the appropriate site.
Five elementary ionic crystal structures of AB, AB 2 , and AB 3 type have been selected for illustration in FIG. 3 . Since the stoichiometries of the crystals vary from 1:1 to 1:3, the Madelung sums of each structure type have been normalized to the energy of a stoichiometric molecule with a configuration giving the lowest Coulombic energy. For a 3:1 crystal the primary unit is triangular, while for a 2:1 crystal it is linear. The fields shown each represent the most stable structure having a Madelung constant greater than one. At small values of Λ, the fields become narrower because the potentials are farther reaching, and fields of Madelung constant less than one arise, due to the greater influence of repulsion between particles of like charge. The fields converge at zero Λ to charge ratios that reflect the stoichiometry of the crystal. For phases of other stoichiometries not shown here, such as an A 2 B 3 structure, a field that converges at the ideal stoichiometry would result (e.g., Q=1.5 for A 2 B 3 ). At small values of Λ, structures containing ordered vacancies may exist in the regions between stable fields, for example between cesium chloride (CsCl) and fluorite (CaF 2 ) fields. This occurs in ionic materials in the form of structure types such as bixbyite and pyrochlore. Ordered defect structures may also exist between the rock salt (NaCl) and wurtzite (ZnS) fields. One of ordinary skill in the art will be able to compute the Madelung constants for these and other alternative structures using the methods described herein. FIG. 3 also does not include the effect of particle radius ratio (Pauling's first rule), which leads to further discrimination between structures, as discussed below.
Specific Particle Systems
We next consider a binary particle system in which the sizes of the two particles as well as their surface charge densities are fixed. The latter may be accomplished by surface functionalization and/or by equilibration with the solution in which the particles are suspended. (Dissimilar colloidal particles can be made to take on opposite charges in a single liquid solution, for instance if the pH of the solution induces one particle to have a positive and the other a negative surface potential/zeta potential.) The surface charges determine the surface potentials of equivalent isolated particles. Q and Λ are then interrelated, and using equations (12) and (13), the Debye parameter (κ) can be eliminated to obtain Q(Λ) as a function of the particle properties, the size ratio, R size =a 1 /a 2 , and the ratio of the particle surface potentials R Ψ =ψ 1 /ψ 2 :
Q
(
Λ
)
=
-
R
Size
R
Ψ
exp
(
Λ
R
Size
-
1
R
size
+
1
)
(
16
)
Note that since the surface potential can be taken to be the zeta potential without loss of generality, R Ψ ovaries with salt concentration. This dependence can be included when calculating R Ψ . FIG. 4 plots this relationship for several particle sizes at a surface potential R Ψ =−0.343. The only variable remaining on these lines is the counterion concentration. A line with a negative slope is in a region where the smaller particle is carrying the largest effective charge. As the counterion concentration increases, the effective charge of the larger particle increases more quickly. At Q=1, the line changes slope as the larger particle begins to carry the larger charge. As the size ratio increases, the slope of the line becomes steeper, making control of the solvent properties more critical. Note that the region the line lies in may not be the dominant phase due to the constraint of Pauling's First Rule, which requires a certain size ratio to fill a site.
For a given value of the Debye parameter, fixed by the choice of salt concentration, solvent dielectric constant, and temperature, the values of Q and Λ are determined by the particle sizes and surface potentials. Conversely, if the particle sizes and surface potentials have been pre-selected through the choice of starting materials, the co-existing values of Q and Λ are determined by the Debye parameter. In either instance, various stability fields within the phase diagram can be accessed through control of the system properties. Combined with control of the particle number ratio (stoichiometry) and size ratio (Pauling's first rule), the most stable structure can be predicted for a given binary colloid system.
These results provide insight into how structures can be selected in practice. FIG. 4 shows that for similar particle sizes (R size approximately 1), the slope of the function (16) is nearly zero, indicating little sensitivity of the charge ratio to counterion concentration. As the particle size ratio becomes larger, however, Q increases exponentially with Λ and is highly sensitive to counterion concentration. A value for Q of less than 1 implies that the surface potential on the smaller particle is greater than that on the larger particle, which may be difficult to achieve. Further, it is very difficult to obtain a useful charge ratio (Q less than 4) if the surface potentials are similar, but the particle sizes are very different. If Q is very much larger than 4, crystalline order will be less favorable than forming local clusters with the highly charged particle at the center, surrounded on all sides by the lower charged particles. The control of Q is therefore important for obtaining ordered structures. As a practical example, to obtain the wurtzite (ZnS) structure, a size ratio between 2.415 (to inhibit the formation of rock salt) and 6.452 (to allow the filling of a tetrahedral site) are desired, as is a charge ratio of nearly one. To satisfy these conditions, the smaller particle must have a much larger surface potential than the larger particle, and, for small values of the Debye parameter, the surface potential on the small particle must be approximately R size times larger than that of the large particle.
Crystal Preparation
The present heterocoagulation-based colloidal crystallization approach may have significant processing advantages over single-component crystallization, being based on attractive rather than repulsive interactions. Crystallization can be more rapid; indeed the nucleation of ICCs may occur within the suspension rather than being determined by the rate of particle settling. Continuous processes using particle mixing can be developed using the techniques described herein. However, growth techniques must appropriately favor controlled growth of ICCs over competing disordered heterocoagulation, which may require fine control of experimental parameters, especially when the free energy difference between the ordered and disordered phases is small.
Where the energy differences between structure types are small, a desired ICC can be preferentially nucleated using a template. For example, calculations performed using the techniques described above show that the wurtzite structure is very slightly favored over zincblende for all values of Q and Λ. For example, at Q=1, the Madelung sum for zincblende is 0.4% lower than that of wurtzite (per unit cell) for all values of Λ. However, the zincblende structure may be technologically important, especially in the field of photonics, due to its large photonic bandgap (see, e.g., Simconov, et al., Physica B 228:245, 1996). Using epitaxial techniques, such as an {001}-orientation template, the FCC-based polymorph can be rendered more energetically favorable (in the vicinity of the epitaxial surface) than the HCP polymorph, allowing growth of the metastable structure.
In another specific embodiment, fluorescent polymer spheres can be fabricated into an ICC having a photonic band gap prohibiting the fluorescence. This structure allows a population inversion to be created in the ICC. With the fabrication of a defect line in the ICC, a self-assembled laser could be produced.
Another specific embodiment involves producing ICCs of mixtures of magnetic and nonmagnetic particles. The resulting structures would be ordered arrays of isolated magnetic particles that could then be used for a variety of applications, including data storage. In addition, field-tunable material could be created by appropriate material selection. Since colloidal crystals are generally expected to be elastically soft (because of their porosity), the incorporation of electrically and magnetically active particles could allow high field response. Electro-optic, magneto-optic, ferroelectric, ferromagnetic, electrostrictive, and magnetostrictive colloidal crystals may all be produced using the methods of the invention.
Nonlinear-conduction devices based on rectifying junctions between dissimilar particles in the ICC may also be produced. Both Schottky-type heterojunctions and p-n junctions can be incorporated depending on the compounds used.
The combination of very high surface area and highly tailorable compositions for ICCs also suggests their usefulness as catalysts, biomaterials (e.g., as scaffolds for tissue growth), or drug delivery media. For example, ICCs can be used to create synthetic zeolites, in which nanoscale colloids would be crystallized to produce engineered mesoporous structures. Unlike present zeolites, the pore size would not be determined by atomic structure but by controlling the colloid particle size and crystal structure, and possibly by thermal densification (sintering) after crystallization. Since a great variety of transition metal oxides can be produced as colloids, catalytic and photocatalytic functions could also be designed into such crystals. Similarly, heterojunction-based gas and chemical sensors having a very fine structure may be produced.
For ICCs having anisotropic crystal structures, microfluidic materials and devices can make use of the controlled, anisotropic porosity of such materials. Mechanically unique structures such as negative Poisson's ratio materials may also be created using the anisotropy of certain ICC structures. For crystallites formed from submicron particles, crystallites may be held in suspension to be used as a scattering medium.
The methodologies presented herein are not limited to two component systems of spherical particles. ICC analogs to covalent or multicomponent crystals can be prepared that have a diversity as rich as mineral crystals. In direct analogy to the ionocovalent nature of real crystals, directional bonding can be introduced into ICCs to create structures preferred by covalent compounds, for example, by through the use of shaped nonspherical particles or through anisotropy in the surface charge on a spherical particle (such anisotropy may be introduced, for example, by utilizing crystalline anisotropy of the particle material, creating an “echo” of the anisotropic structure via the variation in surface charge.) Structures including perovskite and spinel may be produced utilizing a ternary system of particles. The breadth of possible structures and corresponding physical properties suggests potential applications in many fields including photonics, catalysis, structural applications, and biomaterials.
EXAMPLES
Example 1
Nucleation in a rocksalt structure has been demonstrated using 1.5 μm±2.5% silica spheres (Duke Scientific) and 0.76 μm±2% polystyrene functionalized with amidine (PSA) spheres (Interfacial Dynamics, Inc.). Class 1 isopropanol (General Chemical) was used as the solvent, which has a dielectric constant of 20.18, a density of 0.79 g/cm 3 at 68° F., a salt concentration of approximately 10 −8 mol/L, and a Debye parameter of 6.5×10 5 m. Experiments were conducted at room temperature. In this suspension, the larger silica particles bear a negative surface charge (representing the anion), while the smaller PSA particles bear a positive surface charge (representing the cation). The size ratio of 1.974 was chosen to promote octahedral coordination of the PS by the silica. The zeta potential of the silica was measured on ZetaPALS system (Brookhaven Instruments) to be −36.6 mV. The zeta potential of the PSA particles was measured to be 99.3 mV. κa is 0.51 for SiO 2 and 0.25 for PSA under these conditions.
The particles were vacuum filtered to remove any water. The particles were then repeatedly rinsed with 2-Propanol and then resuspended in the 2-Propanol via vortexing. The residual weight from drying a 1 mL sample of each mixture was used to determine the concentration of particles per unit volume. A mixture of 1:1 concentrations of silica and PSA was then produced. The resulting suspension was mixed with 2-Propanol to give an overall concentration of 10 9 particles/mL. This solution was again vortexed for uniform mixing and then pipetted into 1 inch diameter Petri dishes. The dishes were dried and examined using scanning electron microscopy. In one region from 5 mL of mixture dried in a Petri dish, there were 3402 particles visible (1990 of silica and 1412 of PSA), 201 of which were ordered in 35 different clusters containing an average of 5.74 particles per cluster. These ordered clusters constituted 5.9% of the sample. This sample region was chosen at random to represent the entire sample. Certain regions did show a higher concentration of order and larger clusters.
FIGS. 5 a - 5 c are micrographs of the coagulated ICC, taken using an FEI/Philips XL30 FEG ESEM. Areas of rock salt ordering can be seen at the superimposed squares, which show {100} planes of individual ordered regions. Crystal vacancies can be observed at the edges of some ordered areas. Nucleation of rock salt-structure crystallites was observed in all samples tested, suggesting that heterocoagulation at the particle ratio necessary for order occurs spontaneously. The nucleation density in the samples was found to be about 1-5% area fraction for most samples. The nuclei exhibited surfaces of both {100} and {111} orientations. The remainder of the sample exhibited no identifiable crystallographic ordering. We believe that disorder and DLCA may be further minimized through proper control of experimental variables, such as particle uniformity and growth rate, and by controlling growth kinetics as discussed below.
Viewed from the perspective of classical nucleation and growth, the small size of the crystalline regions can be qualitatively understood to be the result of deep undercooling. There exists a “melting point” for an ICC that in this instance is well above room temperature. This “melting point” is the point at which the colloid would melt if the particles themselves were stable at arbitrarily high melting temperatures. (We estimate the melting point for our example system to be about 2500K, well above the melting point of the polystyrene spheres, based on the calculated interaction energy of 460 kT.) At room temperature, the nucleation rate is high and the growth rate low because the system is at a temperature so far below this “melting point.”
To increase the growth rate, the effective temperature of the system may be raised using external energy sources (e.g., ultrasonication, agitation, fluid flow through the sample, or application of alternating electric or magnetic fields). Alternatively, growth can be promoted over unwanted nucleation by decreasing particle concentration to limit supersaturation, and controlling the rate at which particles are supplied, analogous to diffusion-limited liquid- or vapor-phase crystal growth processes.
Example 2
Particle dynamics simulations were conducted on 1.58 μm particles with a surface charge of −23.7 mV and 0.76 μm particles with a surface charge of 114 mV. The simulation was conducted with a salt concentration of 10 −7 mol/L of counterions, giving the particles a charge ratio of Q=1 and a shielding ratio of Λ=2.4. The properties of 2-propanol were used for other variables. Simulations were conducted with Brownian thermal energies of 300K and 1700K. Nearly 100% ordering, with the exception of grain boundaries, occurred when the gravity in the system was increased to between 8 g and 30 g. The best ordering occurred in a range between 15 g and 20 g. The value of gravity needed correlates to the bond strength in the system, so for a system with stronger bonds, more force might be required to obtain the same effects. We believe the increased force is breaking up heterocoagulated colloidal gels that form and are kinetically trapped from reaching a dense crystalline state. The addition of gravitational force is not the only means through which this could be reached. Pressure could be applied directly to the wet colloids after settling breaking up the colloidal gels. In addition, a flow field could apply pressure to the colloids. Any means of adding a strong directional force to the colloids during crystallization should have a similar effect. Results of the simulation are shown in FIGS. 6 a and 6 b . Simulations have shown that this order can extend in upwards of 20 layers from the bottom surface. The top few layers are often more disordered due to surface roughness, so thick crystals should give a larger crystallized fraction.
Example 3
Example 1 was repeated using 3 μm PSA and 6 μm SiO 2 in water (salt concentration=10 −5.5 , dielectric constant=78) giving a charge ratio of Q 18. The zeta potentials in water were approximately 60 mV for PSA and approximately −60 mV for SiO 2 . The resulting disordered structure is shown in FIG. 7 . Note the PSA surrounding the higher charged silica as tightly as possible. κ5.8*10^6 meters, giving a κa of 8.7 for the PSA and 17.5 for the SiO. This example demonstrates that our formulae can be used to identify systems that will not form crystallites.
Other embodiments of the invention will be apparent to those skilled in the art from a consideration of the specification or practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims. | Ionic colloidal crystals (ordered multicomponent colloids formed by attractive electrostatic interactions) may be produced by controlling the surface potential and relative size of multiple populations of colloidal particles in suspension. Such suspensions are dried or otherwise caused to precipitate out the particles in ordered arrays. The crystal structure of the arrays may be controlled by appropriate choices of particle materials, sizes, and charge ratios. | 2 |
CROSS REFERENCE TO RELATED APPLICATIONS
This application is related to and claims priority to U.S. Provisional Application No. 61/465,080, entitled “Robotic Work Object Cell Calibration System and Method,” filed on Mar. 14, 2011; to U.S. Provisional Application No. 61/518,912, entitled “Robotic Work Object Cell Calibration System and Method,” filed on May 13, 2011; to U.S. Ser. No. 13/385,797 “Robotic Work Object Cell Calibration Method” filed on Mar. 7, 2012; and to U.S. Ser. No. 13/385,091 “Robotic Work Object Cell Calibration System,” filed on Feb. 1, 2012. The disclosures of these Applications are hereby incorporated by reference into this specification in their entireties.
FIELD OF USE
The present invention relates to a calibration device and method for an industrial robot and, more particularly, to a calibration method for the industrial robot provided with an imaging device of a visual sensor for detecting a working tool and a working position.
BACKGROUND OF THE INVENTION
The sales of industrial robots that has been driven by the automotive industry, is now moving into tasks as diverse as cleaning sewers, detecting bombs, and performing intricate surgery. The number of units sold increased to 120,000 units in 2010, twice the number as the previous year, with automotive, metal and electronics industries driving the growth.
Prior approaches to calibrating robots use measuring devices that measure either the inaccuracies of the robot after the robot is built or devices which measure work piece positions relative to the robot position prior to off-line programs. Prior art systems involve expensive equipment and specialized users and take longer.
U.S. Patent Application Disclosure No. 20090157226 (de Smet) discloses a robot-cell calibration system for a robot and it's peripheral. The system includes an emitter attached to the robot or its peripheral and emits a laser beam and a receiver also mounted to the robot or its peripheral at a point to permit calibration and for receiving the laser beam and to permit calculations to determine the dimension between the emitter and the receiver. U.S. Pat. No. 6,408,252 (de Smet) discloses a calibration system and displacement measurement device for calibrating a robot system. The system comprises a linear displacement measurement device in conjunction with a robot calibration system. The linear displacement measurement device comprises an elongated member, a drum, a shaft, a drum displacement mechanism and a drum rotation sensor. The drum is displaced axially upon the shaft as the drum rotates when the elongated member is moved. The drum rotation sensor provides accurate information regarding the distance the elongated member travels. The displacement measuring device is used in an iterative manner with the calibration system for the purpose of the calibration of a robotic device. U.S. Pat. No. 6,321,137 (de Smet) discloses a method for calibration of a robot inspection system. The system is used for inspecting a work piece to maintain the accuracy of the robot during inspection of work pieces on a production basis. The system includes means for storing a mathematical model of the robot, means for measuring the position of a target, and then calibrating the robot based upon input from the mathematical model and the position of the target. U.S. Pat. No. 6,044,308 (Huissoon) discloses a method for calibration of pose of a tool contact point (TCP) of a robot controlled tool with respect to a tool sensor means in which the robot controlled tool is attached at an end-point of the robot. A TCP sensor is located in a preselected second pose with respect to the reference fixture for sensing position of the tool contact point. The method includes positioning the tool sensor so that the reference fixture is in a field of view of the tool sensor and calculating a pose of the robot end point with respect to the robot frame of reference, calculating a pose of the reference fixture with respect to the tool sensor means from a sensed position of the four topographically defined features of the reference fixture, and calculating a position of the tool contact point with respect to the reference fixture from a sensed position of the tool contact point with respect to the TCP sensor means.
The primary object of the robotic work object cell calibration method of the present invention is to increase the accuracy of the off-line program and decrease robot teaching time. Still another object of the robotic work object cell calibration method of the present invention is to provide a calibration method which is simpler, results in improved precision, involves a lower investment cost, and which entails lower operating costs than the prior art.
What is needed is a robotic work object cell calibration method for using different robot tools on a shop floor without having to perform a recalibration for each tool. What is needed is a robotic work object cell calibration method that requires no additional computers or software to determine the accuracy of the robot tool or location of peripheral equipment, which uses existing body-in-white procedures, personnel computers and software and ways of communicating information amongst the trades, and requires little or no retraining to deploy.
SUMMARY OF THE INVENTION
The robotic work object cell calibration method of the present invention addresses these objectives and these needs.
In the first preferred embodiment of the present invention, the robotic work object cell calibration method includes a work object or emitter. Initially, the work object is placed in a selected position on a fixture or work piece on the shop floor proximate to the robot.
The work object emits a pair of beam-projecting lasers from an E-shaped extension extending from a central frame. The beam-projecting lasers serve as a crosshair, intersecting at a tool contact point. The work object includes a horizontal frame member that includes a pair of opposing frame ends, and a vertical frame member that includes a pair of opposing frame ends. A plane-projecting laser is preferably disposed at each frame end, respectively, and a projected laser plane is emitted from each of the plane-projecting lasers, respectively. The plane-projecting lasers are used to adjust the roll, yaw, and pitch of the robot tool positioned at the tool contact point on the shop floor.
Method for calibrating a robot using the work object:
First, attach the emitter to the fixture. Using the calibration control unit of the robot, or a laptop computer with a control interface, the tool contact point is aligned to the horizontal beam-projecting lasers emitted from the work object. Using the horizontal and vertical plane-projecting lasers, align the robot tool for roll, yaw, and pitch. Once this is done, note the coordinates and set this position as the zero position in the robot control unit, or in the control panel on the laptop being used to control the robot. This sets the point which the robot will use for its work path. After the point has been set, the robot work path is ready to be used. Now, test the calibration. If the robot does not impact the work object in any way and completes the intended operations, the calibration is done. If not, repeat the above until the work path is properly set.
A second and third preferred embodiments of the work object for use in the robotic work object calibration method of the present invention, comprises only two plane-projecting lasers attached to either the horizontal frame ends or the vertical frame ends. If only two plane-projecting lasers are used, adjustment is limited to either roll and yaw, roll and pitch, or yaw and pitch of the robot tool using said pair of plane-projecting lasers of said work object.
A fourth preferred embodiment of the work object of the present invention comprises only one plane-projecting laser attached to the middle of the work object. The laser head is capable of 360 degrees of rotation, enabling the robot tool to align first on the x-axis, then on the y-axis after the laser head has been rotated.
The robotic work object cell calibration system includes a work object. The work object emits a pair of beam-projecting lasers from an E-shaped extension extending from a central frame. The beam-projecting lasers serve as a crosshair, intersecting at a tool contact point. The work object includes a horizontal frame member that includes a pair of opposing frame ends, and a vertical frame member that includes a pair of opposing frame ends. A plane-projecting laser is preferably disposed at each frame end, respectively, and a projected laser plane is emitted from each of the plane-projecting lasers, respectively. The plane-projecting lasers are used to adjust the roll, yaw, and pitch of the robot tool relative to the tool contact point.
For a complete understanding of the robotic work object cell calibration method of the present invention, reference is made to the following summary of the invention detailed description and accompanying drawings in which the presently preferred embodiments of the invention are shown by way of example. As the invention may be embodied in many forms without departing from spirit of essential characteristics thereof, it is expressly understood that the drawings are for purposes of illustration and description only, and are not intended as a definition of the limits of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts the first preferred embodiment of the work object for use in the robotic work object calibration method of the present invention, the two beam-projecting lasers being used for aligning the tool contact point with the work object.
FIG. 2 depicts the first preferred embodiment of the work object for use in the robotic work object calibration method of FIG. 1 , the four plane-projecting lasers being emitted from the work object.
FIG. 3 depicts an exploded view of the first preferred embodiment of the work object for use in the robotic work object calibration method of FIG. 1 , further depicting the weld gun with the tool contact point of the weld gun aligned to the horizontal and vertical alignment lasers.
FIG. 4 depicts the exploded view of the first preferred embodiment of the work object for use in the robotic work object calibration method of FIG. 3 , further depicting the addition of two pairs of plane-projecting lasers for adjusting the roll, yaw, and pitch of the tool head of the weld gun.
FIG. 5 depicts an assembly view of the first preferred embodiment of the work object for use in the robotic work object calibration method of FIG. 1 , further depicting the work object being mounted onto a fixture with the robot tool head aligned to the two beam-projecting lasers using the tool contact point.
FIG. 6 depicts the assembly view of the work object for use in the robotic work object calibration method of FIG. 5 , further depicting the four plane-projecting lasers being used for adjusting the roll, yaw, and pitch of the tool head of the robot.
FIG. 7 depicts another exploded view of the first preferred embodiment of the work object for use in the robotic work object calibration method of FIG. 6 , further depicting the work object being mounted to the fixture with the robot tool aligned to the tool contact point alignment lasers and the roll, yaw, and pitch alignment lasers.
FIG. 8 depicts an assembly view of a second preferred embodiment of the work object of the work object for use in the robotic work object calibration method of the present invention, two plane-projecting lasers being emitted along the horizontal axis of the work object, a pair of beam-projecting lasers intersecting at a tool contact point, the robot tool being aligned to the tool contact point and to this pair of plane-projecting lasers.
FIG. 9 depicts an assembly view of a third preferred embodiment of the work object of the work object for use in the robotic work object calibration method of the present invention, two plane-projecting lasers being emitted along the vertical axis of the work object, a pair of beam-projecting lasers intersecting at a tool contact point, the robot tool being aligned to the tool contact point and to this pair of plane-projecting lasers.
FIG. 10 depicts a fourth preferred embodiment of the work object of the work object for use in the robotic work object calibration method of the present invention, one plane-projecting laser being emitted along the vertical axis of the work object, and a beam-projecting laser intersecting one of the vertical plane-projecting lasers at a tool contact point.
FIG. 11A depicts a robot and a fixture for use on a shop floor in a prior art embodiment without the work object of FIG. 1 , and FIGS. 11 B and 11 C depict a similar robot, fixture with the work object used in the present invention, showing how in a simplified manner the work object is used to obtain a new zero location and calibrate the path between the fixture and the robot.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, FIGS. 1 and 2 disclose a first preferred embodiment of a work object or emitter [ 10 ] for use in the robotic work object calibration method of the present invention. The work object [ 10 ] is used to calibrate the work path of a robot tool based on a tool contact point (point in space) [ 60 ]. The known point in space
is defined in three dimensions (X, Y, and Z) and relative to their rotational axes R x (pitch), R y (yaw), and R z (roll).
The work object [ 10 ] includes a horizontal frame member [ 22 ] that includes a pair of opposing frame ends [ 32 A and 32 B], and a vertical frame member [ 24 ] that includes a pair of opposing frame ends [ 32 C and 32 D]. A plane-projecting laser [ 41 , 42 , 43 , and 44 ] is preferably disposed at each frame end [ 32 A, 32 B, 32 C, and 32 D], respectively, and a projected laser plane [ 51 , 52 , 53 , and 54 ] is emitted from each of the plane-projecting lasers [ 41 , 42 , 43 , and 44 ], respectively.
Extending along the horizontal frame member [ 22 ] are three arms parallel which combine to form the general shape of the letter “E” of an E-shaped structure [ 25 ] which is horizontally aligned and generally centrally disposed relative to horizontal frame member [ 22 ]. The center arm (not numbered) of the E-shaped structure [ 25 ] is shorter than the two end arms [ 26 A and 26 B].
A first beam-projecting laser [ 58 ] is emitted from the center arm of the “E” disposed at the proximate center of the work object [ 10 ]. A second beam-projecting laser [ 56 ] is emitted from one of the arms [ 26 A] of an E-shaped structure [ 25 ] and is directed into the opposing arm [ 26 B].
The first beam-projecting laser [ 58 ] intersects and is essentially perpendicular and coplanar with the second beam-projecting laser [ 56 ] at a known point in space [ 60 ], defined in three dimensions in terms of X, Y, and Z coordinates.
The first beam-projecting laser [ 58 ] is essentially coplanar with the two projected laser planes [ 51 and 52 ] emitted from the plane-projecting lasers [ 41 and 42 ] emitted from frame ends [ 32 A and 32 B]. Also, the first beam-projecting laser [ 58 ] is essentially coplanar with the two projected laser planes [ 53 and 54 ] emitted from the plane-projecting lasers [ 43 and 44 ] emitted from frame ends [ 32 C and 32 D]. The work object
is mountable onto a fixture [ 90 ] and enables a robot work path to be calibrated relative to the known point in space [ 60 ].
The plane-projecting lasers [ 41 , 42 , 43 , and 44 ] project the four projected laser planes [ 51 , 52 , 53 , and 54 , respectively] from the frame ends [ 32 A, 32 B, 32 C, and 32 D, respectively] of the work object [ 10 ]. The plane-projecting lasers [ 41 , 42 , 43 , and 44 ] are red laser modules, having focused lines (3.5 v-4.5 v 16 mm 5 mw).
The beam-projecting lasers [ 56 and 58 ] are focusable points that project the two laser beams emitted from the arm [ 26 A] of the work object [ 10 ]. The beam-projecting lasers [ 56 and 58 ] are red laser modules, having focusable dots (3.5 v-4.5 v 16 mm 5 mw).
FIG. 3 depicts an exploded view of the work object [ 10 ] for use with a weld gun. The tool contact point [ 60 ] of the weld gun is positioned with respect to the two beam-projecting alignment lasers [ 56 and 58 ]. FIG. 4 further depicts the addition of the four projected laser planes [ 51 , 52 , 53 , and 54 , respectively] from the plane-projecting lasers [ 41 , 42 , 43 , and 44 , respectively] for adjusting the roll, yaw, and pitch of the robot tool head [ 80 ].
FIG. 5 depicts the work object [ 10 ] being mounted onto the fixture [ 90 ]. The robot tool head [ 80 ] is aligned to the two beam-projecting lasers [ 56 and 58 ] using the tool contact point [ 60 ]. FIG. 6 further depicts the four projected laser planes [ 51 , 52 , 53 , and 54 , respectively] from the plane-projecting lasers [ 41 , 42 , 43 , and 44 , respectively] of work piece [ 10 ], which are used to adjust the roll, yaw, and pitch of the robot tool head [ 80 ].
FIG. 7 depicts the work object [ 10 ] mounted onto the fixture [ 90 ] with the robot tool [ 80 ] positioned with respect to the tool contact point [ 60 ] alignment laser beams [ 56 and 58 ] setting the X, Y, and Z coordinates.
FIG. 8 depicts a second preferred embodiment of a work object [ 10 ] for use in the robotic work object calibration method of the present invention. In this embodiment, two projected laser planes [ 51 and 52 ] are emitted from two plane-projecting lasers [ 41 and 42 , respectively] along the horizontal axis of the frame member [ 32 ] of the work object [ 10 ]. The robot tool [ 80 ] is aligned with the tool contact point [ 60 ] and with this pair of projected laser planes [ 51 and 52 ].
FIG. 9 depicts a third preferred embodiment of the work object [ 210 ] for use in the robotic work object calibration method of the present invention. In this embodiment, two projected laser planes [ 53 and 54 ] are emitted from two plane-projecting lasers [ 43 and 44 ] are emitted along the vertical axis of the frame member [ 24 ] of the work object [ 210 ]. The robot tool [ 80 ] is aligned with the tool contact point [ 60 ] and with this pair of projected laser planes [ 53 and 54 ].
FIG. 10 depicts yet another preferred embodiment of the work object [ 10 ] for use in the robotic work object calibration method of the present invention. In this embodiment, one plane projected laser [ 51 ] is emitted from plane-projecting laser along the vertical axis of the work object [ 10 ]. A beam-projecting laser [ 56 ] intersects with the vertical plane-projecting laser [ 53 ] at a tool contact point [ 60 ]. The plane projecting laser [ 51 ] has a rotating head capable of rotating 360°, enabling the robot tool to align first on the x-axis, then on the y-axis after the laser head has been rotated.
FIG. 11A depicts a robot [ 81 ] and a fixture [ 90 ] for use on a shop floor in a prior art embodiment without the work object of the present invention. FIGS. 11 B and 11 C depict a similar robot [ 81 ], and fixture [ 90 ] with the work object [ 10 ], depicting how in a simplified manner the work object [ 10 ] is used to obtain a new zero location and calibrate the path between the fixture [ 90 ] and the robot [ 81 ].
Using CAD simulation software, the CAD user selects a position on the tool to place that is best suited to avoid crashes with other tooling and for ease of access for the robot [ 81 ] or end-of-arm tooling. The offline programs are then downloaded relative to the work object [ 10 ]. The work object [ 10 ] is then placed onto the tool or work piece in the position that is defined by the CAD user on the shop floor. The robot technician then manipulates the tool contact point [ 60 ] of the robot tool [ 80 ] into the device and positions it with respect to the beam-projecting lasers [ 56 and 58 ] to obtain the difference between the CAD world and shop floor. This difference is then entered into the robot and used to define the new work object [ 10 ]. This calibrates the offline programs and defines the distance and orientation of the tool, fixture, and peripheral.
The offline programming with the work object [ 10 ] on the fixture [ 90 ] enable the work object [ 10 ] to be touched up to the “real world position” of the fixture [ 90 ] relative to the robot [ 81 ]. If the fixture [ 90 ] ever needs to be moved or is accidently bumped, simply touch up the work object [ 10 ] and the entire path shifts to accommodate.
The robotic work cell calibrations method of the present invention is compatible with robotic simulation packages, including but not limited to, ROBCAD, Process Simulate, DELMIA, Roboguide and RobotStudio CAD software.
The beam-projecting lasers [ 56 and 58 ] and the projected laser planes [ 51 , 52 , 53 , and 54 ] are projected onto known features of the robot tool [ 80 ], and then used to calibrate the path of the robot tool [ 80 ] and measure the relationship of the fixture relative to the robot tool [ 80 ].
The CAD user initially selects a position best suited on a tool or work piece to avoid crashes with other tooling and for ease of access for the robot or end-of-arm tooling. The work object [ 10 ] preferably mounts onto a fixture [ 90 ] using a standard NAMM's hole pattern mount [ 40 ]. The mounts are laser cut to ensure the exact matching of hole sizes for the mounting of parts.
The robotic work object cell calibration method of the present invention uses a work object [ 10 ] having a zero point, a zero reference frame, and a zero theoretical frame in space, which is positioned on the fixture [ 90 ].
The work object [ 10 ] is placed onto the fixture [ 90 ] which visually represents the work object [ 10 ] enabling the tool contact point of the weld gun to be orientated into the work object [ 10 ] obtaining the “real-world” relationship of the robot tool [ 80 ] to the fixture [ 90 ] while updating the work object [ 10 ] to this “real-world” position.
The robotic work object cell calibration system of the present invention requires that the position of the work object [ 10 ] correlate with the position of the robot tool [ 80 ] to calibrate the path of the robot tool [ 80 ] while acquiring the “real-world” distance and orientation of the fixture [ 90 ] relative to the robot tool [ 80 ].
The robotic work object cell calibration method positions the robot tool [ 80 ] with the work object [ 10 ] and determines the difference.
The robotic work object cell calibration method of the present invention is used to calibrate the work path of a robot tool based on a tool contact point (point in space) [ 60 ]. The calibration uses a “known” work object or frame (robotic simulation CAD software provided work object). The robotic work object cell calibration method of the present invention works by projecting laser beams to a known X, Y, and Z position and defining known geometric planes used to adjust the roll, yaw, and pitch of the robot tool [ 80 ] relative to the tool contact point [ 60 ].
The laser is projected onto the robotic end of the robot arm tooling (weld guns, material handlers, mig torches, etc) where the user will manipulate the robot with end-of-arm tooling into these lasers to obtain the positional difference between the “known” off-line program (simulation provided work object) and the actual (shop floor) work object calibration. The reverse is also true—for instance; a material handler robot can carry the work object [ 10 ] to a know work piece with known features.
The CAD model of the work object [ 10 ] is placed in the robotic simulation CAD world. The CAD user selects a position best suited on a toot or work piece to avoid crashes with other tooling and for ease of access for the robot or end-of-arm tooling. The off-line programs are then downloaded relative to this work object [ 10 ]. The work object
will be placed onto the tool or work piece in the position that was defined by the CAD user on the shop floor. The robot technician then manipulates the tool contact point [ 60 ] into the device, aligning it to the laser beams to obtain the difference between the CAD world and shop floor. This difference is then entered into the robot and used to define the new work object, thus calibrating the off-line programs and defining the distance and orientation of the tool, fixture, peripheral, and other key components.
The robotic work object cell calibration method of the present invention calibrates the paths to the robot [ 81 ] while involving the calibration of the peripherals of the robot.
The laser plane generating system deployed in the robotic work object cell calibration method of the present invention is well known in the art—see for example U.S. Pat. No. 5,689,330 (Gerard, et al.), entitled “Laser Plane Generator Having Self-Calibrating Leveling System”; and U.S. Pat. No. 6,314,650 (Falb), entitled “Laser System for Generating a Reference Plane”.
The robotic work object cell calibration method of the present invention aids in the kiting or reverse engineering of robotic systems for future use in conjunction with robotic simulation software allowing integrators the ability to update their simulation CAD files to the “real world” positions.
The technology uses existing body-in-white procedures, personnel computers and software and ways of communicating information amongst the trades.
Throughout this application, various Patents and Applications are referenced by number and inventor. The disclosures of these documents are hereby incorporated by reference into this specification in their entireties in order to more fully describe the state of the art to which this invention pertains.
It is evident that many alternatives, modifications, and variations of the robotic work object cell calibration system of the present invention will be apparent to those skilled in the art in light of the disclosure herein. It is intended that the metes and bounds of the present invention be determined by the appended claims rather than by the language of the above specification, and that all such alternatives, modifications, and variations which form a conjointly cooperative equivalent are intended to be included within the spirit and scope of these claims.
PARTS LIST
10 . work object (1 st preferred embodiment)
22 . horizontal frame member
24 . vertical frame member
25 E-shaped structure
26 A and 26 B. arms
32 A. left frame end (horizontal)
32 B. right frame end (horizontal)
32 C. upper frame end (vertical)
32 D. lower frame end (vertical)
40 . NAMM's mounting
41 . plane-emitting laser from left-side of horizontal frame
42 . plane-emitting laser from right-side of horizontal frame
43 . plane-emitting laser from upper vertical frame
44 . plane-emitting laser from lower vertical frame
51 . projected laser plane from plane-emitting laser ( 41 )
52 . projected laser plane from plane-emitting laser ( 42 )
53 . projected laser plane from plane-emitting laser ( 43 )
54 . projected laser plane from plane-emitting laser ( 44 )
56 . laser beam from arm ( 26 A)
58 . laser beam from center of “E”
60 . tool contact point
80 . robot tool
81 . robot
82 . robot joint
85 A. & 85 B. robot linkages
87 . robot base
90 . fixture
110 . 2 nd work object
210 . 3 rd work object 310 . 4 th work object | The robotic work object cell calibration method includes a work object or emitter. Initially, placing the work object is placed in a selected position on a fixture or work piece on the shop floor. The work object emits a pair of beam-projecting lasers which intersect at a tool contact point and act as a crosshair. The robot tool is manipulated into the tool contact point. The work object emits four plane-projecting lasers which are used to adjust the roll, yaw, and pitch of the robot tool relative to the tool contact point. The robotic work object cell calibration method of the present invention increases the accuracy of the off-line programming and decreases robot teaching time. | 6 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 11/427,738, filed on Jun. 29, 2006, entitled “Systems and methods for posterior dynamic stabilization of the spine”, which is a continuation-in-part of U.S. patent application Ser. No. 11/436,407, filed on May 17, 2006, entitled “Systems and methods for posterior dynamic stabilization of the spine”, which is a continuation-in-part of U.S. patent application Ser. No. 11/033,452, filed on Jan. 10, 2005, entitled “Systems and methods for posterior dynamic stabilization of the spine”, which is a continuation-in-part of U.S. patent application Ser. No. 11/006,495, filed on Dec. 6, 2004, entitled “Systems and methods for posterior dynamic stabilization of the spine”, which is a continuation-in-part of U.S. patent application Ser. No. 10/970,366, filed on Oct. 20, 2004, entitled “Systems and methods for posterior dynamic stabilization of the spine”. U.S. patent application Ser. No. 11/427,738, filed on Jun. 29, 2006, entitled “Systems and methods for posterior dynamic stabilization of the spine” is a continuation-in-part of U.S. patent application Ser. No. 11/362,366, filed on Feb. 23, 2006, entitled “Systems and methods for stabilization of bone structures”, which claims priority to U.S. Provisional Patent Application Ser. No. 60/701,660, filed on Jul. 22, 2005, entitled “Systems and methods for stabilization of bone structures”. This application is also a continuation-in-part of U.S. patent application Ser. No. 11/726,093, filed on Mar. 20, 2007, entitled “Screw systems and methods for use in stabilization of bone structures”, which is a continuation-in-part of U.S. patent application Ser. No. 11/586,849, filed on Oct. 25, 2006, entitled “Systems and methods for stabilization of bone structures”, which is a continuation-in-part of U.S. patent application Ser. No. 11/362,366, filed on Feb. 23, 2006, entitled “Systems and methods for stabilization of bone structures”, which claims priority to U.S. Provisional Patent Application Ser. No. 60/701,660, filed on Jul. 22, 2005, entitled “Systems and methods for stabilization of bone structures”. U.S. patent application Ser. No. 11/726,093, filed on Mar. 20, 2007, entitled “Screw systems and methods for use in stabilization of bone structures” is also a continuation-in-part of U.S. patent application Ser. No. 11/427,738, filed on Jun. 29, 2006, entitled “Systems and methods for posterior dynamic stabilization of the spine”, which is a continuation-in-part of U.S. patent application Ser. No. 11/436,407, filed on May 17, 2006, entitled “Systems and methods for posterior dynamic stabilization of the spine”, which is a continuation-in-part of U.S. patent application Ser. No. 11/033,452, filed on Jan. 10, 2005, entitled “Systems and methods for posterior dynamic stabilization of the spine”, which is a continuation-in-part of U.S. patent application Ser. No. 11/006,495, filed on Dec. 6, 2004, entitled “Systems and methods for posterior dynamic stabilization of the spine”, which is a continuation-in-part of U.S. patent application Ser. No. 10/970,366, filed on Oct. 20, 2004, entitled “Systems and methods for posterior dynamic stabilization of the spine”. This application is also a continuation-in-part of U.S. patent application Ser. No. 11/726,093, filed on Mar. 20, 2007, entitled “Screw systems and methods for use in stabilization of bone structures”, which is a continuation-in-part of U.S. patent application Ser. No. 11/586,849, filed on Oct. 25, 2006, entitled “Systems and methods for stabilization of bone structures”, which is a continuation-in-part of U.S. patent application Ser. No. 11/362,366, filed on Feb. 23, 2006, entitled “Systems and methods for stabilization of bone structures”, which claims priority to U.S. Provisional Patent Application Ser. No. 60/701,660, filed on Jul. 22, 2005, entitled “Systems and methods for stabilization of bone structures”. All of the above applications are claimed for their benefit of priority and are further incorporated herein by reference in their entirety.
FIELD
[0002] The present invention is directed towards the treatment of spinal disorders and pain. More particularly, the present invention is directed to systems and methods of treating the spine which reduce pain and enable spinal motion, and which effectively mimic that of a normally functioning spine.
BACKGROUND
[0003] FIGS. 1A and 1B illustrate a portion of the human spine having a superior vertebra 2 and an inferior vertebra 4 , with an intervertebral disc 6 located in between the two vertebral bodies. The superior vertebra 2 has superior facet joints 8 a and 8 b, inferior facet joints 10 a and 10 b, posterior arch 16 and spinous process 18 . Pedicles 3 a and 3 b interconnect the respective superior facet joints 8 a, 8 b to the vertebral body 2 . Extending laterally from superior facet joints 8 a, 8 b are transverse processes 7 a and 7 b, respectively. Extending between each inferior facet joint 10 a and 10 b and the spinous process 18 are lamina 5 a and 5 b, respectively. Similarly, inferior vertebra 4 has superior facet joints 12 a and 12 b, superior pedicles 9 a and 9 b, transverse processes 11 a and 11 b, inferior facet joints 14 a and 14 b, lamina 15 a and 15 b, posterior arch 20 , spinous process 22 .
[0004] The superior vertebra with its inferior facets, the inferior vertebra with its superior facets, the intervertebral disc, and seven spinal ligaments (not shown) extending between the superior and inferior vertebrae together comprise a spinal motion segment or functional spine unit. Each spinal motion segment enables motion along three orthogonal axes, both in rotation and in translation. The various spinal motions are illustrated in FIGS. 1C-1E . In particular, FIG. 1C illustrates flexion and extension motions and axial loading, FIG. 1D illustrates lateral bending motion and translation, and FIG. 1E illustrates axial rotational motion. A normally functioning spinal motion segment provides physiological limits and stiffness in each rotational and translational direction to create a stable and strong column structure to support physiological loads.
[0005] Traumatic, inflammatory, metabolic, synovial, neoplastic and degenerative disorders of the spine can produce debilitating pain that can affect a spinal motion segment's ability to properly function. The specific location or source of spinal pain is most often an affected intervertebral disc or facet joint, and in particular the nerves in and around the intervertebral disc or facet joint. Often, a disorder in one location or spinal component can lead to eventual deterioration or disorder, and ultimately, pain in another.
[0006] Spine fusion (arthrodesis) is a procedure in which two or more adjacent vertebral bodies are fused together once the natural height of the degenerated disc has been restored. It is one of the most common approaches to alleviating various types of spinal pain, particularly pain associated with one or more affected intervertebral discs. However, fusion is only as good as the ability to restore disc height to relieve the pain by taking pressure off the nerves, nerve roots, and/or articulating surfaces—i.e., facet joints and end plates of the vertebral bodies.
[0007] One way of accomplishing fusion is to install pedicles screws in adjacent vertebral bodies, followed by installation of fusion rods between the screws. This type of system can be strengthened by attaching a cross-connector between the fusion rods. In many current systems, however, attachment and deployment of such a cross-connector is difficult.
[0008] With the limitations of current spine stabilization technologies, there is clearly a need for an improved means and methods for stabilization of the spine which addresses the drawbacks of prior devices. In particular, it would be highly beneficial to have a fusion stabilization system that has high strength and that enables the spine to mimic the motion of one or more healthier, uncompromised vertebral segments, especially with regard to torsional motions. It would be additionally beneficial if such a system could be conveniently installed and used to treat various spinal indications regardless of pain source, prevent or slow the deterioration of the intervertebral discs, or even restore disc height, and be used in conjunction with prosthetic intervertebral discs.
SUMMARY OF THE INVENTION
[0009] According to one aspect of the invention, a spinal stabilization system is provided. The system includes a first rod attachment element configured to connect to a first vertebral stabilization rod. A second rod attachment element configured to connect to a second vertebral stabilization rod. The system includes a first bar attached to the first rod attachment element and a second bar attached to the second rod attachment element. The system includes a connector connecting the first and second bars. At least one rod attachment element has a two-part design such that one part of the two-part design contacts one portion of a corresponding rod and the other part of the two-part design contacts another portion of the corresponding rod to capture the rod.
[0010] According to another aspect of the invention, a spinal stabilization system for a patient is provided. The system includes a first rod attachment element configured to connect to a first vertebral stabilization rod. The first rod attachment element includes a first biasing section. The system includes a second rod attachment element configured to connect to a second vertebral stabilization rod. The second rod attachment element includes a second biasing section. The system includes a first bar connected to the first rod attachment element and a second bar connected to the second rod attachment element. A connector is provided that connects the first and second bars. At least the first rod attachment element further comprises a rod-contacting surface and a corresponding screw having a head with a cam section such that rotation of the screw having a head with a cam section into the rod attachment element forces the cam section towards the rod-contacting surface capturing the rod between the rod-contacting surface and the cam section.
[0011] According to another aspect of the invention, a spinal stabilization system for a patient is provided. The system includes a first rod attachment element configured to connect to a first vertebral stabilization rod and a second rod attachment element configured to attach to a second vertebral stabilization rod. A cross-connector configured to connect the first and second rod attachment elements is also provided. At least one rod attachment element has a two-part design such that one part of the two-part design contacts one portion of a corresponding rod and the other part of the two-part design contacts an other portion of the corresponding rod to capture the rod.
[0012] According to another aspect of the invention, a method for stabilizing a patient's spine is provided in which a first set of two pedicle screw systems is installed into a superior vertebral segment. A second set of two pedicle screw systems is installed into an inferior vertebral segment. A first rod is connected between one of the pedicle screw systems in the first set and one of the pedicle screw systems in the second set. A second rod is connected between the other of the pedicle screw systems in the first set and the other of the pedicle screw systems in the second set. A first rod attachment element is connected to the first rod and a second rod attachment element is connected to the second rod. A first bar is connected to the first rod attachment element and a second bar is connected to the second rod attachment element. A cross connector is connected to both the first bar and the second bar. At least one rod attachment element has a two-part design such that one part of the two-part design contacts one portion of a corresponding rod and the other part of the two-part design contacts an other portion of the corresponding rod to capture the rod.
[0013] According to another aspect of the invention, a method for stabilizing a patient's spine is provided in which a first set of two pedicle screw systems is installed into a superior vertebral segment. A second set of two pedicle screw systems is installed into an inferior vertebral segment. A first rod is connected between one of the pedicle screw systems in the first set and one of the pedicle screw systems in the second set. A second rod is connected between the other of the pedicle screw systems in the first set and the other of the pedicle screw systems in the second set. A first rod attachment element is connected to the first rod and a second rod attachment element is connected to the second rod. A cross-connector is connected between the first and second rod attachment elements. At least one rod attachment element has a two-part design such that one part of the two-part design contacts one portion of a corresponding rod and the other part of the two-part design contacts another portion of the corresponding rod.
[0014] According to another aspect of the invention, a spinal stabilization system for a patient is provided. The system includes a first rod attachment element configured to attach to a first vertebral stabilization rod and a second rod attachment element configured to attach to a second vertebral stabilization rod. The system includes a cross-connector configured to connect the first and second rod attachment elements. At least one rod attachment element has a two-part design such that one part of the two-part design contacts one portion of a corresponding rod and the other part of the two-part design contacts an other portion of the corresponding rod to capture the rod. The one and the other parts of the two-part design move relative to each other upon the tightening of a screw.
[0015] According to another aspect of the invention, a spinal stabilization system for a patient is provided. The system includes a first rod attachment element configured to attach to a first vertebral stabilization rod and a second rod attachment element configured to attach to a second vertebral stabilization rod. A cross-connector configured to connect the first and second rod attachment elements is provided. At least one rod attachment element has a two-part design such that a first part of the two-part design contacts a circumferential portion of a corresponding rod along a portion thereof, and the other part of the two-part design contacts a portion of the first part. The one and the other parts of the two-part design move relative to each other upon the tightening of a screw, and movement of the other part causes the first part to tighten around the circumferential portion of the rod.
[0016] According to another aspect of the invention, a spinal stabilization system for a patient is provided. The system includes a first rod attachment element configured to attach to a first vertebral stabilization rod and a second rod attachment element configured to attach to a second vertebral stabilization rod. A cross-connector coupled between the first and second rod attachment elements is provided. The first and second rod attachment elements define openings for capturing first and second vertebral stabilization rods, and the openings face in a substantially anterior direction when the rods are being captured.
[0017] According to another aspect of the invention, a method for stabilizing a patient's spine is provided. The method includes the step of installing a first set of two pedicle screw systems into a superior vertebral segment. A second set of two pedicle screw systems is installed into an inferior vertebral segment. A first rod is connected between one of the pedicle screw systems in the first set and one of the pedicle screw systems in the second set. A second rod is connected between the other of the pedicle screw systems in the first set and the other of the pedicle screw systems in the second set. A first rod attachment element is connected to the first rod, and a second rod attachment element is connected to the second rod. At least one of the first and second rod attachment elements is connected by moving the rod attachment element, having an anteriorly-facing opening, towards the rod, such that the rod enters the opening in the rod attachment element in a posterior direction.
[0018] According to another aspect of the invention, a method for stabilizing a patient's spine is provided. In the method, a first set of two pedicle screw systems is installed into a superior vertebral segment. A second set of two pedicle screw systems is installed into an inferior vertebral segment. A first rod is connected between one of the pedicle screw systems in the first set and one of the pedicle screw systems in the second set. A second rod is connected between the other of the pedicle screw systems in the first set and the other of the pedicle screw systems in the second set. A first rod attachment element is connected to the first rod, and a second rod attachment element is connected to the second rod. A cross-connector is connected between the first and second rod attachment elements. A screw is provided in the cross-connector. The method includes the step of and the cross-connector is configured such that tightening one screw in the cross-connector such that the one tightening prevents all polyaxial and/or translational movement of the cross-connector relative to the first and second rod attachment elements.
[0019] According to another aspect of the invention, a spinal stabilization system for a patient is provided. The system includes a first rod attachment element configured to attach to a first vertebral stabilization rod and a second rod attachment element configured to attach to a second vertebral stabilization rod. A cross-connector attached between the first and second rod attachment elements is provided. The system is configured such that the cross-connector is displaced by a predetermined distance in a posterior direction relative to a point where at least one rod attachment element attaches to a bar. The displacement accommodates the shape of the anatomy and bridges anatomy located anterior of the cross-connector.
[0020] According to another aspect of the invention, a spinal stabilization system for a patient is provided. The system includes a first rod attachment element configured to attach to a first vertebral stabilization rod and a second rod attachment element configured to attach to a second vertebral stabilization rod. A cross-connector attached between the first and second rod attachment elements is provided. The first rod attachment element defines an interior surface that is configured to encompass a rod along as great a percentage of a circumference of the rod as possible while allowing the rod to be snap-fit into the rod attachment element.
[0021] According to another aspect of the invention, a method for stabilizing a patient's spine is provided. In the method, a first set of two pedicle screw systems is installed into a superior vertebral segment and a second set of two pedicle screw systems is installed into an inferior vertebral segment. A first rod is connected between one of the pedicle screw systems in the first set and one of the pedicle screw systems in the second set. A second rod is connected between the other of the pedicle screw systems in the first set and the other of the pedicle screw systems in the second set. A first rod locking procedure is performed by connecting a first rod attachment element to the first rod in a snap-fit manner. A second rod locking procedure is performed by connecting a second rod attachment element to the second rod in a snap-fit manner.
[0022] According to another aspect of the invention, a centered spinal stabilization system for a patient is provided. The system includes a first rod attachment element configured to attach to a first vertebral stabilization rod and a second rod attachment element configured to attach to a second vertebral stabilization rod. A cross-connector attached between the first and second rod attachment elements is provided. The first rod attachment element defines a channel having a rod-contacting surface that is configured to engage a rod and to center the rod in the channel when the rod is fully engaged.
[0023] According to another aspect of the invention, a spinal stabilization system for a patient is provided. The system includes a first rod attachment element to attach to a first vertebral stabilization rod and a second rod attachment element to attach to a second vertebral stabilization rod. A cross-connector coupled between the first and second rod attachment elements is provided. The first and second rod attachment elements define a first and second channel having first and second rod-contacting surfaces for capturing first and second vertebral stabilization rods. At least one of the first rod-contacting surface and second rod-contacting surface includes a gripping surface along a portion thereof.
[0024] According to another aspect of the invention, a spinal stabilization system for a patient is provided. The system includes a first rod attachment element configured to attach to a first vertebral stabilization rod and a second rod attachment element configured to attach to a second vertebral stabilization rod. A cross-connector coupled between the first and second rod attachment elements is provided. The cross-connector is coupled to the first rod attachment element by a first screw and to the second rod attachment element by a second screw. At least one of these couplings includes a slot such that the corresponding screw can slide a distance along the slot prior to tightening of the screw to allow for variations in patient anatomy.
[0025] According to another aspect of the invention, a method for stabilizing a patient's spine is provided. In the method, a first set of two pedicle screw systems is installed into a superior vertebral segment and a second set of two pedicle screw systems is installed into an inferior vertebral segment. A first rod is connected between one of the pedicle screw systems in the first set and one of the pedicle screw systems in the second set and a second rod is connected between the other of the pedicle screw systems in the first set and the other of the pedicle screw systems in the second set. A first rod attachment element is connected to the first rod and a second rod attachment element is connected to the second rod. A cross-connector is connected between the first and second rod attachment elements such that the cross-connector is coupled to the first rod attachment element by a first screw and to the second rod attachment element by a second screw, and at least one of the couplings includes a slot wherein the corresponding screw can slide a distance along the slot prior to tightening to allow for variations in patient anatomy.
[0026] According to another aspect of the invention a spinal stabilization system for a patient is provided. The system includes a first rod attachment element configured to attach to a first vertebral stabilization rod and a second rod attachment element configured to attach to a second vertebral stabilization rod. A cross-connector is configured to connect the first and second rod attachment elements and has a locked configuration and an unlocked configuration such that the cross-connector moves relative to at least one of the first and second rod attachment elements while in the unlocked configuration.
[0027] According to another aspect of the invention, a spinal stabilization system for a patient is provided. The system includes a first rod attachment element configured to attach to a first vertebral stabilization rod and a second rod attachment element configured to attach to a second vertebral stabilization rod. A first bar is provided and connected to the first rod attachment element. The first bar extends towards the second rod attachment element. A second bar is provided and connected to the second rod attachment element and extends towards the first rod attachment element. One of the first or second bars overlaps at least a portion of the other of the first or second bars and a cross-connector is provided to connect the first and second bars together at the overlapping portion.
[0028] Advantages of the invention may include one or more of the following. Devices according to embodiments of the invention may be easily installed once other spinal components are installed, such as screws, rods, dynamic elements, facet constructs, and so on. The cross-connector system allows ease of operator assembly and surgical placement, and allows multi-degree-of-freedom adjustability prior to final stabilization. The cross-connector system further allows repositioning in subsequently-performed procedures. Devices according to embodiments of the invention may have a low profile and be minimally invasive.
[0029] Systems according to the invention may be employed to treat various spinal disorders and pain, including those involving degenerative disc disease, spinal stenosis, spondylolisthesis, spinal deformities, fractures, pseudarthrosis, tumors, failed fusions, arthritic facet joints, severe facet joint tropism, facet joint injuries, deformed facet joints, scoliosis, and other vertebral segment traumas and diseases.
[0030] These and other objects, advantages, and features of the invention will become apparent to those persons skilled in the art upon reading the details of the invention as more fully described below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] The invention is best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not to-scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Included in the drawings are the following figures:
[0032] FIGS. 1 (A)-(B) illustrate certain aspects of the anatomy of spinal segments.
[0033] FIGS. 1 (C)-(E) illustrate various spinal movements that may be performed by the spinal segments of FIGS. 1 (A)-(B).
[0034] FIG. 2 (A) illustrates a side schematic view of a cross-connector with accompanying rod attachment elements and rods according to a first embodiment of the invention.
[0035] FIG. 2 (B) illustrates an exploded perspective view of a cross-connector according to the first embodiment of the invention.
[0036] FIG. 3 illustrates a side view of a cross-connector according to the first embodiment of the invention.
[0037] FIG. 4 illustrates a side schematic view, in partial cross-section, of a cross-connector system according to a second embodiment of the invention.
[0038] FIGS. 5 (A)-(D) illustrate exploded and non-exploded perspective and side cross-sectional views of a cross-connector according to a third embodiment of the invention.
[0039] FIG. 6 illustrates a perspective view of a cross-connector according to a fourth embodiment of the invention.
[0040] FIGS. 7 (A)-(B) illustrate perspective and exploded views of a cross-connector according to a fifth embodiment of the invention.
[0041] FIG. 8 illustrates a perspective exploded view of a cross-connector according to a sixth embodiment of the invention.
[0042] FIGS. 9 (A)-(E) illustrate various views of a cross-connector system according to a seventh embodiment of the invention.
[0043] FIGS. 10 (A)-(C) illustrate sectional perspective, top, and side views of the cross-connector system according to the seventh embodiment of the invention.
[0044] FIGS. 11 (A)-(B) illustrate side sectional and perspective views of the cross-connector system according to the seventh embodiment of the invention.
[0045] FIG. 12 illustrates an exploded perspective view of a cross-connector system according to an eighth embodiment of the invention.
[0046] FIGS. 13 (A)-(C) illustrate sectional perspective, top, and side views of the cross-connector system according to the eighth embodiment of the invention.
[0047] FIGS. 14 (A)-(C) illustrate top, bottom, and detailed views of the cross-connector system according to the eighth embodiment of the invention.
[0048] FIGS. 15 (A)-(C) illustrate perspective and side views, in partial cross-section, of a cross-connector system according to a ninth embodiment of the invention.
[0049] FIGS. 16 (A)-(C) illustrate more detailed views of the cross-connector system according to the ninth embodiment of the invention.
[0050] FIGS. 17 (A)-(C) illustrate more detailed views of the cross-connector system according to the ninth embodiment of the invention.
[0051] FIGS. 18 (A)-(D) illustrate more detailed views of the cross-connector system according to the ninth embodiment of the invention.
[0052] FIGS. 19 (A)-(B) illustrate side and perspective exploded views of a cross-connector system according to a tenth embodiment of the invention.
[0053] FIGS. 20 (A)-(C) illustrate more detailed views of the cross-connector system according to the tenth embodiment of the invention.
[0054] FIGS. 21 (A)-(B) illustrate more detailed views of the cross-connector system according to the tenth embodiment of the invention.
[0055] FIG. 22 illustrates a detailed view of an alternative cross-connector system related to the tenth embodiment of the invention.
[0056] FIGS. 23 (A)-(B) illustrate side and perspective exploded views of a cross-connector system according to an eleventh embodiment of the invention.
[0057] FIG. 24 illustrates a more detailed view of the cross-connector system according to the eleventh embodiment of the invention.
[0058] FIGS. 25 (A)-(B) illustrate side and perspective exploded views of a cross-connector system according to a twelfth embodiment of the invention.
[0059] FIGS. 26 (A)-(B) illustrate more detailed views of the cross-connector system according to the twelfth embodiment of the invention.
[0060] FIGS. 27 (A)-(B) illustrate side and perspective exploded views of a cross-connector system according to a thirteenth embodiment of the invention.
[0061] FIGS. 28 (A)-(C) illustrate more detailed views of the cross-connector system according to the thirteenth embodiment of the invention.
[0062] FIGS. 29 (A)-(B) illustrate more detailed views of the cross-connector system according to the thirteenth embodiment of the invention.
[0063] FIG. 30 illustrates a detailed view of an alternative cross-connector system related to the thirteenth embodiment of the invention.
DETAILED DESCRIPTION
[0064] Before the subject devices, systems and methods are described, it is to be understood that this invention is not limited to particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.
[0065] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
[0066] It must be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a spinal segment” may include a plurality of such spinal segments and reference to “the screw” includes reference to one or more screws and equivalents thereof known to those skilled in the art, and so forth.
[0067] Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limits of that range is also specifically disclosed. Each smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in that stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range, and each range where either, neither or both limits are included in the smaller ranges is also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.
[0068] All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates which may need to be independently confirmed.
[0069] The present invention will now be described in greater detail by way of the following description of exemplary embodiments and variations of the systems and methods of the present invention. While more fully described in the context of the description of the subject methods of implanting the subject systems, it should be initially noted that in certain applications where the natural facet joints are compromised, as illustrated in FIG. 1 (A), inferior facets 10 a and 10 b, lamina 5 a and 5 b, posterior arch 16 and spinous process 18 of superior vertebra 2 may be resected for purposes of implantation of certain of the dynamic stabilization systems of the present invention. In other applications, where possible, the natural facet joints, lamina and/or spinous processes are spared and left intact for implantation of other dynamic stabilization systems of the present invention.
[0070] It should also be understood that the term “system”, when referring to a system of the present invention, most typically refers to a set of components which includes a superior, cephalad or rostral (towards the head) component configured for implantation into a superior vertebra of a vertebral motion segment and an inferior or caudal (towards the feet) component configured for implantation into an inferior vertebra of a vertebral motion segment. A pair of such component sets includes one set of components configured for implantation into and stabilization of the left side of a vertebral segment and another set configured for the implantation into and stabilization of the right side of a vertebral segment. The left set of components may move independently of the right set of components or their motions may be coordinated via an attachment between the two. In other words, they may move in conjunction with one another, with both moving relative to the more fixed attachment between the two. Many of the systems disclosed here concern such an attachment between the two.
[0071] Where multiple spinal segments or units are being treated, the term “system” may refer to two or more pairs of component sets, i.e., two or more left sets and/or two or more right sets of components. Such a multilevel system involves stacking of component sets in which each set includes a superior component, an inferior component, and one or more medial components therebetween. These multilevel systems may include cross member or cross connector components or strut systems having differing properties, e.g., lengths, limits on travel or other limited ranges of motion; resistance to motion or other forces, attachment locations, etc.
[0072] The superior and inferior components (and any medial components therebetween), when operatively implanted, are engaged or interface with each other in a manner that enables the treated spinal motion segment to mimic the function and movement of a natural healthy segment. The disclosed systems include one or more structures or members which enable, limit and/or otherwise selectively control spinal motion. The structures may perform such functions by exerting various forces on the system components, and thus on the target vertebrae. The manner of coupling, interfacing, engagement or interconnection between the subject system components may involve compression, distraction, rotation or torsion, or a combination thereof. In certain embodiments, the extent or degree of these forces or motions between the components may be intraoperatively selected and/or adjusted to address the condition being treated, to accommodate the particular spinal anatomy into which the system is implanted, and to achieve the desired therapeutic result, such as to restore disc height and offset the facet joints.
[0073] In certain embodiments, the superior and inferior components are mechanically coupled to each other by one or more interconnection or interfacing means. In other embodiments, the superior and inferior components interface in an engaging manner which does not necessarily mechanically couple or fix the components together but rather constrains their relative movement and also enables the treated spinal motion segment to mimic the natural function and movement of a healthy segment. Typically, the interconnecting means is a posteriorly-positioned component, i.e., one positioned posteriorly of the superior and inferior components, or it may be a laterally-positioned component, i.e., one positioned to the outer side of the posterior and inferior components. The structures may involve one or more strut systems and/or joints which provide for dynamic movement of a stabilized spinal motion segment.
[0074] In this description, the following terms are used throughout, and are defined here. A “cross-connector system” is a device that extends between and attaches to two fixation or stabilization rods. A “rod attachment element” forms a portion of a cross-connector system, and is the portion of the cross-connector system that attaches to the rod. The portion of the cross-connector system, that is not the rod attachment element, is the cross connector itself.
[0075] It is noted that the following patent applications, owned by the assignee of the present invention and incorporated herein by reference in their entirety for all purposes, disclose various dynamic rod systems, pedicle screw systems, and facet augmentation systems that may be employed in conjunction with the current invention: U.S. patent application Ser. No. 11/427,738, filed on Jun. 29, 2006, entitled “Systems and methods for posterior dynamic stabilization of the spine”; U.S. patent application Ser. No. 11/436,407, filed on May 17, 2006, entitled “Systems and methods for posterior dynamic stabilization of the spine”; U.S. patent application Ser. No. 11/033,452, filed on Jan. 10, 2005, entitled “Systems and methods for posterior dynamic stabilization of the spine”; U.S. patent application Ser. No. 11/006,495, filed on Dec. 6, 2004, entitled “Systems and methods for posterior dynamic stabilization of the spine”; U.S. patent application Ser. No. 10/970,366, filed on Oct. 20, 2004, entitled “Systems and methods for posterior dynamic stabilization of the spine”; U.S. patent application Ser. No. 11/726,093, filed on Mar. 20, 2007, entitled “Screw systems and methods for use in stabilization of bone structures”; U.S. patent application Ser. No. 11/586,849, filed on Oct. 25, 2006, entitled “Systems and methods for stabilization of bone structures”; U.S. patent application Ser. No. 11/362,366, filed on Feb. 23, 2006, entitled “Systems and methods for stabilization of bone structures”; U.S. Provisional Patent Application Ser. No. 60/701,660, filed on Jul. 22, 2005, entitled “Systems and methods for stabilization of bone structures”; all of which are incorporated by reference herein in their entirety.
[0076] In many of the systems described, the adjustability of the system may be used to prevent undesired stress on spine and system components. The adjustability also provides for a simplified installation process. To this end, the requirements for precision on drilling locations, angles, etc., may be reduced. In the same way, an installation kit may be provided with a lesser number of components, as the provided components can accommodate more varying anatomy. Thus, in many systems, the components are aligned to the anatomy and then tightened.
[0077] FIG. 2 (A) shows a high-level design of a top-loading cross-connector system 51 in side view. The cross-connector system 51 includes a cross connector 50 and two rod attachment elements 52 a and 52 b. Bars 68 a and 68 b extend from the rod attachment elements 52 a and 52 b toward a connector 56 . Two rods 70 a and 70 b are shown as well, with the cross-connector system 51 in a loading position above the rods. As may be seen in the figure, rod attachment elements 52 a and 52 b each have arch-shaped channels 53 a and 53 b defined therein to engage rods 70 a and 70 b, respectively.
[0078] Bars 68 a and 68 b may be individually or collectively formed integral with or pre-attached to either rod attachment elements 52 a and 52 b, or with connector 56 , or both. This alternative is true for any of the embodiments described in this application, unless otherwise noted.
[0079] In use, and in general for all of the systems, pedicle screw systems are installed in the pedicles of a patient, and rods 70 a and 70 b, as well as additional rods or less rods as necessary, are installed between the pedicle screws. Once the rods are installed, one or more rod attachment elements are affixed to the rods. If the rod attachment elements include bars and/or connectors in a pre-attached or integral fashion, then the technique is completed following attachment of the rod attachment elements or bars to any unattached elements. If the rod attachment elements do not include bars and/or connectors in a pre-attached or integral fashion, then the bars are attached to the rod attachment elements. If at least one bar includes a connector in a pre-attached or integral fashion, then the technique is completed following any necessary affixation of the connector to either bar. If the bars do not include a connector in a pre-attached or integral fashion, then the connector is attached to the bars, and the technique is completed. For this system and for the other cross-connector systems described, once an implantation procedure is completed, all components may be fixed relative to one another, preventing relative motion. Alternatively, one or more components may be secured and yet relative motion may still be allowed, such as resiliently-biased motion via a dynamic element or otherwise. Motions may also be permitted such as simple rotation or sliding motions, such as via a spring-biased attachment. One example of this may be the sliding swivels described in embodiments below. When the cross-connector components are tightened, all swivel motion may be prevented or alternatively some limited motions may continue to be allowed, in one or more directions.
[0080] FIG. 2 (B) shows a cross-connector system 51 in more detail. The cross-connector system 51 includes rod attachment elements 52 a and 52 b, as well as a cross connector 50 . A two-part rod attachment element 52 a includes (the rod attachment element 52 b has similar corresponding elements, though each rod attachment element may be different if dictated by the application) a clamp assembly having a biasing section or hook 76 a and a pivoting clamp 78 a.
[0081] In this and in other embodiments, the “two-part rod attachment element” refers to a rod attachment element in which one element or a portion of one element is moved toward another element in order to secure a rod therebetween, but generally neither of these elements, in this embodiment, is a screw, though a screw may be used to move one element towards another element. Moving one element towards another may include either translation or rotational motion or both. Moving one element towards another may tend to provide a clamping action or the like. It should be noted that “moving one element towards another” refers to any action that can secure a rod, such as the above described clamping action. Indeed, the actual amount that elements are moved towards each other may be minimal (and parts of the elements may even move away from each other), and substantial movement is not required. In another embodiment, described below, one of the elements is a screw with a cam portion.
[0082] A locking screw 82 a serves to, upon installation, force the pivoting clamp 78 a towards hook 76 a, thereby clamping the hook against the pivoting clamp and thus securing the rod attachment element to the rod 70 a. It should be noted that the hook need not clamp against the pivoting clamp in an extreme sense; it may be sufficient that the hook pivots to reduce the internal diameter of the arch-shaped channels such that the hook and pivoting clamp capture and apply force to the rod.
[0083] In more detail, the hook 76 a includes two side pieces 57 a and 59 a joined at a central piece 61 a. Hingedly attached to the hook 76 a is the pivoting clamp 78 a. A hinge 86 a is shown in FIG. 3 to demonstrate this attachment. Also shown in FIG. 3 is the hole 63 a defined in pivoting clamp 78 a into which the screw 82 a is installed. As may be seen in that figure, a bottom surface 69 a of the head of the screw 82 a forms an angle 65 a with the top surface 67 a of the hook 76 a. Downward translation of the screw 82 a forces surfaces 69 a and 67 a together (reducing angle 65 a ), and causes rotation of the hook 76 a in the direction indicated by arrow 80 , the rotation being about the hinge 86 a. When the hook 76 a rotates in this direction, a rod-contacting portion 88 a of the rod attachment element clamps down on the rod 70 a, securing it against movement. The rod-contacting portion 88 a of the rod attachment element preferably encircles the rod 70 a by greater than 180°.
[0084] As noted, bar 68 a extends from a central section 55 a of the rod attachment element 52 a, and may be integral with or pre-attached to the same. The central section is installed within the biasing or hook section 76 a, but may also be integral therewith.
[0085] In an alternative embodiment, the bar 68 a may be installed in (e.g. screwed into) rod attachment element 52 a after rod attachment element 52 a is attached to the rod 70 a. Bar 68 a includes a swivel 72 a that translates along a groove 84 a. The swivel 72 a, at its radial extreme, approximates a spherical shape. When disposed in a corresponding approximately-spherical cavity within opening 74 a in cross connector 56 , the swivel's shape allows a degree of polyaxial movement or adjustment of each rod attachment element relative to the cross connector. For example, the rod attachment element may rotate about an axis 60 parallel to the longitudinal axis of the cross connector. This may be particularly important when accommodation is necessary for non-parallel rods. Of course, following such polyaxial adjustment, the system may be tightened down, prohibiting future movements, for most fusion procedures. As another adjustment mechanism, the groove 84 a allows a constrained degree of translational movement and adjustment along axis 60 . That is, the bar may move in or out of the swivel, to accommodate various spacings between rods.
[0086] The cross connector 56 includes a connector top 62 and a connector bottom 58 . The connector top 62 and the connector bottom 58 engagedly mate and are affixed via an bar clamping screw 64 which is installed through a hole 66 a defined in connector top 62 and which is threaded into a threaded hole 66 b defined in connector bottom 58 . The bar clamping screw or the threaded hole may be provided with an anti-rotation feature, such as a nylon insert or metal swage.
[0087] Once the bar clamping screw is installed in holes 66 a and 66 b, further movement of the swivels along the groove, as well as polyaxial motion, may be prohibited. Alternatively, installation of the bar clamping screw 64 may only serve to prevent removal, while allowing one or both of these motions.
[0088] While the above embodiment has been described with respect to the rod attachment element with elements having “a” suffixes, a similar description applies to the rod attachment element with elements having “b” suffixes.
[0089] In use, after the rods 70 a and 70 b are attached to the installed pedicle screws, the rod attachment elements above may be attached to the rods by placing the rods against rod-contacting portion 53 a (a corresponding portion, 53 b, is not shown), and tightening screws 82 a and 82 b into holes 63 a and 63 b (hole 63 a is indicated in FIG. 3 ). The bars 68 a and 68 b along with swivels 72 a and 72 b may then be disposed in the voids 74 a and 74 b of the cross connector 56 , i.e., in the connector bottom 58 , with the swivels located along the grooves 84 a and 84 b. The connector top 62 is then placed above the connector bottom 58 and the screw 64 is inserted through the hole 66 a and is threaded into hole 66 b. Once tightened, the system is secured and the procedure concluded. In an alternative embodiment, the connector top and connector bottom are secured first, or partially secured first, and then the rod attachment elements are secured to the rods.
[0090] FIG. 4 shows a second embodiment of the invention, with some elements in common with the embodiment of FIGS. 2-3 . A cross-connector system 90 is shown with two-part rod attachment elements 92 a and 92 b, and a cross connector 91 . In this embodiment, the cross connector 91 includes a dynamic element 114 . The dynamic element 114 may include any type of element that can provide a degree of motion to the cross connector 91 , including the types of dynamic elements disclosed in U.S. patent Ser. No. 11/427,738. For example, the dynamic element may provide a resilient bias, such as with a flexible portion or a spring. One or more characteristics of dynamic element 91 may be adjustable (adjustment means not shown but may be, e.g., a rotatable set screw), such as an adjustment to the range of motion and/or a force applied to resist motion.
[0091] The cross connector 91 further includes depending cylindrical projections 112 a and 112 b, these depending from opposite sides of the dynamic element 114 . Into each cylindrical projection 112 a and 112 b may be placed corresponding bars 106 a and 106 b, respectively. As in the first embodiment, the bars 106 a and 106 b have disposed thereon swivels 108 a and 108 b. The swivels 108 a and 108 b may slide along, and/or pivot within, a groove as in the first embodiment (not shown in FIG. 4 ).
[0092] FIG. 4 shows the bars 106 a and 106 b as threadingly engaging the rod attachment elements 92 a and 92 b, though may also be constructed integral to the same. If threadingly engaged, they may be pre-attached before the surgical installation procedure or attachment may be contemporaneous, during the surgical installation procedure.
[0093] In FIG. 4 , the rod attachment element 92 a is displayed as being of a different construction from the rod attachment element 92 b. In more detail, the rod attachment element 92 a includes dual screws 94 a and 96 a that may be employed to grasp a rod at rod-contacting surface 116 a. While not indicated in FIG. 4 , they may act in a way similarly to that of FIG. 3 , in which the bottom surface of the screw head contacting the top surface of the rod attachment element causes a pivoting action, closing the rod attachment element around the rod. In an alternative embodiment (not shown), the two screws 94 a and 96 a may each contact an interior surface of the clamp assembly. This contact may then deflect the contacted surface in a way to clamp around the rod. The screw 94 a deflects the left side and screw 96 a deflects the right side. In any case, the two screws 94 a and 96 a may cause rod-contacting portion 116 a to close in a complimentary fashion around the rod.
[0094] The rod attachment element 92 a is also shown with a drug delivery element 104 . The drug delivery element 104 may be appropriately configured to provide a time-release of, e.g., an antibiotic drug, and may be refillable via an injection port integral to drug delivery element 104 (injection port not shown). Such a drug delivery element may be provided or performed on any of the described embodiments.
[0095] The rod attachment element 92 b also has some similarities to the rod attachment element 52 b, with the following differences. First, either the screw 94 b or the rod attachment element 92 b may be provided with a nylon insert 98 to provide an anti-rotation function. The nylon insert 98 may be replaced with a metal swage or the like to perform a similar function. The rod attachment element 92 b also incorporates a cover 102 to cover the head of the screw 94 b. Such a contamination cover may be provided on any of the described embodiments. The cover 102 may be replaced with a degree of filling of the hole, such as by an elastomer. Either will serve to help prevent tissue in-growth, or the ingress of other forms of contamination. Keeping this area free of contamination may provide significant assistance in post-procedural adjustment or removal. Another difference between the rod attachment elements 92 b and 52 b is that 92 b uses a single screw 94 b to activate clamping function.
[0096] In use, after the rods 70 a and 70 b are attached to the installed pedicle screws, the rod attachment elements above may be attached to the rods by placing the rods against rod-contacting portions 116 a and 116 b, and tightening screws 94 a, 94 b, and 96 a into their respective holes. The bars 106 a and 106 b along with swivels 108 a and 108 b may then be disposed in the voids of the cross connector 91 in any of the manners disclosed above or below. The bars may be pre-installed in the cross connector during, e.g., the time of construction of the dynamic element. Once tightened, the system is secured and the procedure concluded. In an alternative embodiment, the bars are secured to the cross connector first, and then the rod attachment elements are secured to the rods. In another alternative embodiment, dynamic element 114 is adjusted such as at a time prior to, during and/or after implantation of cross-connector system 90 .
[0097] FIG. 5 (A)-(D) illustrates a cross-connector system 120 according to a third embodiment of the invention, this embodiment incorporating certain features of the aforedescribed embodiments.
[0098] In FIG. 5 (A), two stabilizing rods 110 a and 110 b are engaged by two corresponding two-part rod attachment elements 118 a and 118 b. The rod attachment elements 118 a and 118 b each have a biasing section or hook section 126 a and 126 b, respectively, which operate in conjunction with sliding clamps 128 a and 128 b to grasp rods 110 a and 110 b.
[0099] In more detail, sliding clamps 128 a and 128 b each have corresponding hook-engaging elements 132 a and 132 b (see FIG. 5 (D)) which are slidingly received by corresponding holes defined in the hook sections 126 a and 126 b. At the opposite end of each of sliding clamps 128 a and 128 b is a section defining an upwardly-facing recess 134 a and 134 b. Two rod-locking screws 138 a and 138 b are provided to tighten the sliding clamps 128 a and 128 b to the hook sections 126 a and 126 b, and this tightening is accomplished by the rod-locking screws 138 a and 138 b each being installed in holes 142 a and 142 b and then respectively engaging the recesses 134 a and 134 b (note 134 b is not shown in the figure). That is, once the hook-engaging elements 132 a and 132 b are slidingly received by the corresponding holes defined in the hook sections 126 a and 126 b, they cannot be forced downward any further, and the downward pressure of the rod-locking screws 138 a and 138 b then serves to frictionally engage and make secure the connection between the hook sections and the clamps, as well as closing around the rods. The presence of the recesses tends to secure the clamps in a predetermined position relative to the hook sections, this predetermined position chosen to ensure sufficient force is applied against the rods 110 a and 110 b to secure the same against movement.
[0100] The cross connector 121 as shown in FIG. 5 (C) includes a body section 123 from which depends two clamp sections 122 a and two clamp sections 122 b. The two clamp sections 122 a and two clamp sections 122 b each form a “C” clamp, and each has a hole defined therein through which screws 124 a and 124 b may be inserted to tighten the respective clamp sections. A swivel 144 b is shown in FIG. 5 (C) in a position in which the same may be inserted into the cross connector 121 . A bore of the swivel allows entry into the swivel of a bar. Following insertion, the swivel 144 b may be rotated such that it can no longer be removed from the cross connector 121 under normal motions encountered by the cross-connector system 120 in normal patient use.
[0101] In use, after the rods 110 a and 110 b are attached to the installed pedicle screws, the rod attachment elements may be attached to the rods by placing the rods between the hook and the clamp sections, and tightening screws 138 a and 138 b into holes 142 a and 142 b. The bars 136 a and 136 b along with swivels 144 a and 144 b may then be disposed in the voids of the cross connector 121 . That is, the bars are inserted into the swivels, rotated, and then advanced into the voids of cross connector 121 >. The screws 124 a and 124 b may then be installed and tightened, securing the bars and swivels against further movement. Once tightened, the system is secured and the procedure concluded. In an alternative embodiment, the cross connector 121 is constructed and secured first, and then the rod attachment elements are secured to the rods.
[0102] FIG. 6 shows an embodiment of the invention, similar to that of FIG. 5 (A)-(D), in which a single screw provides the compressive force. In particular, two rods 110 a and 110 b are attached to two two-part rod attachment elements 131 a and 131 b, respectively, via two respective screws 138 a and 138 b. Of course, other attachment mechanisms can also be employed. The rod attachment elements 131 a and 131 b each have a corresponding bar 127 a and 127 b, which form a part of a cross-connector system 141 . The cross-connector system 141 also includes a cross connector portion 146 , formed of a wrap-around partial cylindrical portion 147 which is attached in its general mid-section to a top projecting portion 152 a and a bottom projecting portion 152 b, which when forced together by a screw 148 tends to frictionally hold the bars 127 a and 127 b in a predetermined and desired relationship.
[0103] In use, the system of FIG. 6 is constructed in a manner similar to that of FIG. 5 (A)-(D), except that only one bar clamping screw need be tightened.
[0104] FIGS. 7 (A) and 7 (B) show a related embodiment, in which a two-piece cross connector 139 includes an upper housing 159 with a projecting mid-portion. While the reference numerals for common elements remain the same as in FIG. 6 , changed elements include the upper housing 159 which engages a lower housing 154 . The upper housing 159 and lower housing 154 are held together via a screw 162 . The screw 162 is inserted through a downwardly-projecting section 158 that defines a hole therethrough. The upper housing 159 has a first portion 156 a which engages a bar 127 a and a second portion 156 b which engages a bar 127 b. In both cases, the first and second portions primarily engage their respective corresponding bars via contacting the swivels that are slid onto the bars, though the first and second portion may in some cases also contact the bars themselves. The screw 162 is inserted through a hole 158 in the upper housing 159 and is threaded into a threaded hole 161 in the lower housing 154 .
[0105] In use, after the rods 110 a and 110 b are attached to the installed pedicle screws, the rod attachment elements may be attached to the rods by placing the rods between the hook and the clamp sections, and tightening screws 138 a and 138 b into their respective holes. The bars 127 a and 127 b along with their corresponding swivels may then be disposed in the voids of the cross connector 139 , i.e., in the lower housing 154 . The upper housing 159 is then placed above the lower housing 154 and the screw 162 is inserted through the hole 158 and is threaded into hole 161 . Once tightened, the system is secured and the procedure concluded. In an alternative embodiment, the upper and lower housings are secured first, and then the rod attachment elements are secured to the rods.
[0106] FIG. 8 shows a related embodiment. Whereas the embodiment of FIGS. 7 (A) and (B) included an upper housing with a downwardly-projecting mid-portion where the downwardly-projecting mid-portion stabilizes internal components, the embodiment of FIG. 8 includes a lower housing with a upwardly-projecting mid-portion, this upwardly-projecting mid-portion similarly capable of stabilizing internal components. In particular, the cross-connector system 149 includes an upper housing 166 and a lower housing 164 , the lower housing having a raised mid-portion 153 in which is defined a threaded hole 151 . A screw 168 is inserted through a hole 172 in the upper housing 166 and is threaded into the threaded hole 151 .
[0107] In use, the system of FIG. 8 is constructed in a manner similar to that of FIG. 7 (A)-(B).
[0108] FIGS. 9 (A)-(E) illustrate another embodiment of the invention. In this embodiment, as will be described, the rod attachment element snaps over a rod and a screw insertion closes a clamp around the rod. In addition, the bars include upper and lower bars with portions that overlap, slide and mate with each other. In this embodiment, the cross connector may be formed of a single piece that surrounds both the upper and lower bars at a single cross-sectional location. A screw may directly contact the bars, compressing them together.
[0109] In more detail, and referring initially to FIG. 9 (A), a cross-connector system 170 includes first and second rod attachment elements 174 a and 174 b, each having a respective rod-contacting portion 194 a and 194 b for contacting rods (a rod 110 a is shown in FIG. 9 (D)). The rod-contacting portions may be generally sized such that the same contact the rods around as great a percentage of the rods as possible. Of course, if the rod-contacting portions are sized to extend around too great a circumference, the rods would not be able to be installed within the rod-contacting portions in a snap-fit fashion; in this case, pre-installation or pre-engagement would be necessary. Moreover, the rod-contacting portions are generally circular in cross-section. The radius of the circle described may be chosen such that the rod is automatically centered when the rod is installed in the rod attachment element. That is, in most embodiments the rod should not move around within the rod-contacting portion of the rod attachment element. In many cases, this means that the center of the rod-contacting portion and the center of the rod are substantially coincident when the rod is installed. The above features of the rod-contacting portions may be extended to various other embodiments in this description.
[0110] The rod attachment elements 174 a and 174 b have corresponding bars 198 a and 198 b. The bars 198 a and 198 b are configured to attach to their respective rod attachment elements at different heights, so that one may be slid on top of another when the two are each inserted through a hole 188 in a unitary cross connector 176 . The hole 188 may have an appropriate shape to allow a substantial clamping effect when an bar clamping screw 186 is threadingly inserted through a hole 192 defined in the top of the cross connector 176 . A distal end 187 of the screw 186 may mate with a corresponding recess in the top of the bar 198 a (see FIG. 10 (A)). The tolerances of the bars in the hole 188 may be such as to allow a degree of rotation, as best seen in FIG. 9 (E). In other words, the bars need not be exactly collinear. The allowed rotation may be about an axis defined by a nub 202 in the bar 198 a which mates with a recess 204 in the bar 198 b (see FIG. 10 (A)).
[0111] As may be seen in FIG. 9 (D), the cross-connector is displaced a certain distance in a posterior direction from a position where the rod attachment element attaches to a rod. This displacement allows the system to accommodate the shape of and bridge the anatomy in the vertebral region. That is, the bars 198 a and 198 b are above the line defined by the cross-sectional midpoints of rods 110 a and 110 b at the point of attachment to the cross-connector 170 . FIGS. 15 (A)-(C) show a related embodiment, where the bridge-like accommodation is provided by the cross-connecting forming a domed shape.
[0112] Referring back to FIGS. 9 (A)-(D), the rod-contacting surfaces 194 a and 194 b may surround the rod by greater than 180°, and may be provided with a roughened surface or coating so as to enhance the same's grip on the rod. The roughened surface may be accomplished via grit-blasting the surface, defining knurling, serrations, or splines thereon, or the like, and the same may be provided or performed on any of the described embodiments. Besides increasing the grip, various other advantages may inure to embodiments including serrations or the like. For example, the removal of material from the rod-contacting surface may allow the rod to slide more easily due to decreased friction. Similarly, the removal may allow the rod attachment element, or its biasing or hook section, to flex more easily.
[0113] Referring to FIG. 9 (C), at an inner extremity 179 of the rod-contacting surface 194 a, two opposite-facing projections may be provided. Of course, the same may be provided on the rod attachment element 174 b. A first projection 175 may project in a direction such that the first projection 175 further circumferentially surrounds a rod 110 a disposed adjacent the rod-contacting surface 194 a. The presence of this first projection 175 may also be such that the rod 110 a, when placed adjacent the rod-contacting surface 194 a, in fact “snap-fits” into the volume defined by the same. This snap-fit may in some cases be sufficient attachment of the rod attachment element to the rod. In many cases, however, this snap-fit will not be sufficient but will serve to help the clinician to precisely position and adjust the connector allowing movement of the connector relative to the rod before completely locking down the device to the rod.
[0114] One way of increasing the grip of the rod attachment element on the rod is via use of a second projection 177 . Two screws 178 a and 178 b are provided, each with respective threads 184 a and 184 b and respective tapering portions 182 a and 182 b, for insertion into the rod attachment elements 174 a and 174 b in holes 196 a and 196 b As best seen in FIG. 9 (C), as the screw 178 a is inserted into the hole 196 a, the leading edge of the screw, adjacent the tapering portion 182 a, contacts the second projection 177 and deflects the same in a direction away from the screw 178 a, i.e., towards the rod 110 a. In particular, the second projection 177 is deflected under the rod 110 a, surrounding the rod a greater angular distance and increasing the level of contact and pressure between the rod attachment element and the rod, further frictionally securing the rod against the rod attachment element.
[0115] As noted above, a certain degree of rotation is allowed in the system to accommodate situations where the bars are required to be non-collinear. The amount of allowed rotation can vary and can be predetermined based on various factors, especially the width of the bars, their width at their distal tips, and the width of the cross connector 176 . This type of alignment, which may be intraoperative, is indicated by arrows 190 and 190 ′ in FIG. 10 (B). The tolerances of the bars and the hole 188 may further allow for a degree of rotation out of the plane defined by arrows 190 and 190 ′, i.e., in directions defined by arrows 180 and 180 ′ in FIG. 10 (C). Generally, various movements, such as rotation, translation, etc., are usually prevented by further tightening of the associated screws prior to completion of the procedure.
[0116] The cross connector 176 may include screw threads 192 which have an anti-rotation feature, or the screw 186 may have an anti-rotation feature, as has been described in connection with other screws above. The tip of the bar clamping screw 186 may engagingly mate with a recess 201 on the upper surface of the bar 198 a, i.e., the surface opposite that of nub 202 .
[0117] FIG. 11 (A) indicates the embodiment in cross-section, as well as how the cross connector may be slid along the bars to accommodate various placement locations. To further assist the engagement of the bars as the cross connector is translated, the bars may have a number of nubs and recesses to accommodate various placement locations (just one nub and recess is shown in FIG. 11 (A) for clarity).
[0118] FIG. 11 (B) indicates an alternative embodiment of the rod attachment element 174 b. In FIG. 11 (B), the rod attachment element 174 b is composed in part of a slotted arrangement that makes up part of the rod-contacting surface. The central section 208 performs the functions described above in connection with FIGS. 9 and 10 . In addition, as the central section 208 is separated from the remainder of the rod attachment element, at least in the region of the rod-contacting surface, the second projection may be easier and more convenient to deflect. The remainder of the rod attachment element, in the region of the rod-contacting surface, comprises a set of peripheral sections 206 and 212 which provide additional strength to the rod attachment element.
[0119] Referring back to FIG. 9 (A)-(E), after the rods 110 a and 110 b are attached to the installed pedicle screws, the rod attachment elements may be attached to the rods by placing the rods against rod-contacting surfaces 194 a and 194 b, and tightening screws 178 a and 178 b into their respective holes. The tightening of screws 178 a and 178 b flexes undercuts 175 a and 175 b further under the rod, further securing the same against movement. The bars 198 a and 198 b are then inserted in an overlapping fashion into the void 188 of cross connector 176 , such that the nub 202 engages the recess 204 . A degree of orientation may be performed by the physician, to accomplish a particular treatment goal, following which the screw 186 is threadingly inserted into the hole 192 . Once tightened, the system is secured and the procedure concluded. In an alternative embodiment, the bars are engaged to the cross connector first, and then the rod attachment elements are secured to the rods.
[0120] In many insertion procedures, the screws are inserted and tightened to a point where the same are not fully tightened. Following this, the system can be adjusted according to the preferences of the physician, and then the screws fully tightened to prevent undesired motion.
[0121] Referring to FIG. 12 , an alternative embodiment of a cross-connector system is shown. Certain features are in common with above-described embodiments. For example, two rod attachment elements 214 a and 214 b are shown, each with a corresponding bar 222 a and 222 b. The bar 222 a has a nub 226 on a lower portion of a distal end 224 a while, on an upper portion, the same has a recess 225 . The bar 222 b has a recess 228 along a portion of its length. When the two bars are inserted into a hole 232 in cross connector 230 , the same may be tightened into position by inserting a bar clamping screw 250 having tip 254 and threads 252 into threaded hole 234 .
[0122] Each rod attachment element has a threaded hole 218 a (or 218 b ) and a biasing section or hook section 216 a (or 216 b ). The hook section has a concave surface for contacting a portion of a rod (not shown). Two rod attachment element screws 238 a and 238 b are provided, one each for threading engagement with corresponding holes 218 a and 218 b. The two rod attachment element screws 238 a and 238 b have respective threads 242 a and 242 b and respective heads 244 a and 244 b. The heads 244 a and 244 b each have a corresponding eccentric cam section 246 a and 246 b.
[0123] FIG. 13 (A) shows a perspective cross-section of this embodiment's configuration. Referring to FIG. 13 (B), a degree of rotational movement or adjustment may be allowed as indicated by arrows 210 and 210 ′. In addition, a degree of rotational movement or adjustment may be allowed, out of the plane defined by arrows 210 and 210 ′, this degree of rotational movement indicated by FIG. 13 (C) as arrows 220 and 220 ′. As noted above, once the proper adjustment is made, generally for reasons of patient geometry accommodation, the system is tightened, preventing further movement. Of course, various degrees of freedom may be non-tightened if desired to allow movement with respect to that degree of freedom.
[0124] The cam position may be indicated by markers 256 and 258 , located on the bar and on the screws (see FIG. 13 (B)). Top and bottom views are also shown in FIGS. 14 (A) and (B). A detail of the head 244 a is shown in FIG. 14 (C). This figure shows cam section 246 a, marker 258 , as well as intended direction of rotation 260 , for left-handed threads. The marker on the screw and the marker on the bar may be employed to align starting positions, ending positions, etc. For example, aligned markers may indicate a starting position, where the cam is not engaged with the rod, and a 90° rotation may then be employed to capture the rod.
[0125] A captured rod is placed in juxtaposition with the cross-connector in a functional manner, such as for example, in juxtaposition with the rod attachment element of the cross-connector. A captured rod may be permitted free movement, limited movement, or no movement. In some embodiments, and depending on the level to which tightening of, e.g., screws, is performed, the rod may be permitted no movement, sliding movement, limited rotational movement, significant rotational movement, and so on.
[0126] In use, after the rods are attached to the installed pedicle screws, the rod attachment elements may be attached to the rods by placing the rods against rod-contacting surfaces 216 a and 216 b, and tightening screws 238 a and 238 b into their respective holes. With this tightening, the cam section 246 a locks against the rod, both frictionally arresting and mechanically preventing movement of the rod out of the rod attachment element. That is, the cam section 246 a may force the rod against the hook section 216 , and thus frictionally secure the same against movement. The cam section 246 a can also, with appropriate design, take a position under the rod and force the same upward against the rod attachment element, thus mechanically preventing removal, at least removal via a downward motion. The degree of frictional arrest and mechanical movement prevention may be adjusted by choice of geometry of the cam, the rod, and rod attachment element hook section, and to a lesser degree by the type of materials chosen for construction. In all installation techniques, the physician may be aware of the positioning of the cam section via the markers.
[0127] The bars 222 a and 222 b are then inserted in an overlapping fashion into the void 232 of cross connector 236 , such that the nub 226 engages the recess 228 . A degree of orientation may be performed by the physician, to accomplish a particular treatment goal, following which the screw 250 is threadingly inserted into the hole 234 . As noted above, in typical installations, the screw 250 is inserted first, but not fully tightened. The physicians orients the system properly, and then fully tightens screw 250 . Once tightened, the system is secured and the procedure concluded. In an alternative embodiment, the bars are engaged to the cross connector first, and then the rod attachment elements are secured to the rods.
[0128] FIGS. 15 (A)-(C) show another embodiment of the invention. In this embodiment, rods 270 a and 270 b are shown coupled to two-part rod attachment elements 272 a and 272 b, this coupling occurring as will be described in a different manner than the above-described embodiments. Rod-locking screws 274 a and 274 b assist in creating this coupling. A cross connector 280 is shown with a housing 276 and further employing screws 278 a and 278 b, these screws clamping directly on respective swivels 282 a and 282 b and/or on respective bars 281 a and 281 b.
[0129] Additional details of this embodiment are shown in FIGS. 16-18 .
[0130] First, details of the rod-locking screw system are shown in FIG. 16 (A)-(B). Referring to FIG. 16 (A), the rod attachment element 272 a includes a rod-locking screw 274 a which is inserted into a clamp 286 a. The clamp 286 a includes an upwardly-projecting screw receiver 288 a with internal threads 292 a. The clamp 286 a is inserted into a housing 273 a, the housing having a rod-receiving channel 290 a and a bar 281 a, on which is mounted the swivel 282 a as will be described. The clamp 286 a has a curved rod-receiving lower surface 291 a which acts to surround the rod 270 a.
[0131] Referring to FIG. 16 (C), the swivel 282 a is mounted on the bar 281 a. In particular, radially-inward projections 296 a and 298 a may together be inserted into a groove 285 a in the bar 281 a. This engagement may serve as a retaining feature, maintaining the swivel on the bar but still allowing sliding of the swivel on the bar for, e.g., width adjustment.
[0132] Referring to FIGS. 16 (A) and 17 (A)-(D), the orientation of the clamp 286 a may be adjusted to ease rod insertion. FIG. 17 (A) shows the orientation prior to insertion of the rod. The surface 291 a and the rod-receiving channel 290 a are rotationally-oriented such that the rod may be easily inserted, the configuration just after insertion shown in FIG. 17 (B). The clamp 286 a may then be rotated as shown in FIG. 17 (C), at which point a portion of the clamp is forced against the rod and the same transmits a force against the rod-receiving channel 290 a, frictionally securing the components together. That is, in one orientation, first and second portions of the rod attachment element are arranged such that a rod may enter the rod-receiving channel. In another orientation, the first and second portions of the rod attachment element are arranged such that the rod is locked in the rod-receiving channel.
[0133] To maintain the frictional engagement, the screw 274 a may be rotated in a direction shown by arrow 302 , causing a downward movement of the screw indicated by arrow 300 . The tightening of the rod-locking screw causes the clamp to compress around the rod, in the directions indicated by arrows 304 and 306 , and the tightening may be maintained until the rod is rigidly attached, both axially and rotationally. The rotation of the screw and clamp causes the rod to be clamped between portions 307 and 309 (see FIG. 17 (D)). This is termed a “scissor” design. When the screw 274 is tightened, the clamping force is enhanced.
[0134] The bar clamping screws 278 a and 278 b may act directly on the swivels 282 a and 282 b, and on the bars 281 a and 281 b, and may serve to frictionally secure the combination against movement following installation. To install the swivels onto the bar, the same may be either slid on or snap-fit over. To install the swivels and bars into the cross connector 280 , the swivel, bar, and rod attachment element combination may be rotated to the position shown in FIG. 18 (A). The swivel may then be inserted through a swivel insertion slot 293 , which as shown in FIG. 18 (B) has a horizontal dimension X and a vertical dimension Y. The vertical dimension Y is less than the outer radius of the swivel. The swivel has a substantially spherical surface to accommodate polyaxial orientations prior to tightening of all screws. The housing 276 is provided with a slot on its general underside to accommodate the bar in this position.
[0135] FIG. 18 (B) shows the swivel partially inserted in the cross connector 280 , and FIG. 18 (C) shows the swivel fully inserted in the cross connector 280 . Following this full insertion, the swivel, bar, and rod attachment element combination may be rotated to the position shown in FIG. 18 (D), which is approximately the appropriate position for use in a patient.
[0136] In use, after the rods 270 a and 270 b are attached to the installed pedicle screws, the rod attachment elements may be attached to the rods by placing the rods in the rod-receiving channels 290 a and 290 b, following the procedures of FIGS. 17 (A)-(D), and tightening screws 274 a and 274 b. The bars 281 a and 281 b along with their corresponding swivels 282 a and 282 b may then be disposed in the voids of the cross connector 280 in the manner described by FIGS. 18 (A)-(D). The screws 278 a and 278 b may then be tightened, securing the swivels and bars in the cross connector. In an alternative embodiment, the cross connector is connected to the bars first, and then the rod attachment elements are secured to the rods.
[0137] In some embodiments, the bars may be omitted, and the rod attachment elements may attach directly to a cross connector. For example, referring to FIGS. 19 (A)-(B) and 20 (A)-(C), a cross-connector system 300 is shown with rod attachment elements 302 a and 302 b, a cross connector 306 spanning them. The rod attachment element 302 a includes a housing 303 a with a throughhole 305 a defined therein, a biasing section or hook section 318 a, and a post hole 320 a defined therein. The rod attachment element 302 b has similar components, although the structure of rod attachment element 302 b may be entirely different if dictated by the requirements of the user.
[0138] A base 312 a is provided corresponding to each rod attachment element 302 a, the base 312 a including a threaded hole 314 a and a post 316 a. When constructed, a c-clip 310 a is disposed between the rod attachment element housing 303 a and the base 312 a. The c-clip 310 a may snap onto a thread or groove on the screw, so that, in combination with the head on the screw, the cross connector and the rod attachment element are frictionally engaged. The rod attachment element 302 b may employ similar components.
[0139] The cross connector 306 has one or more holes defined therein, which are shown in FIG. 19 (B) as holes 308 a and 308 b. The holes may be elongated, as shown, to allow a set of screws 304 a and 304 b to occupy a variety of locations along the elongated hole, as may be required (see FIG. 20 (A)). The holes 308 a and 308 b may be provided with a depression, so that when a screw is inserted therethrough, the screw head is flush with or below the level of the cross connector 306 (see FIG. 20 (C)). The screws 304 a and 304 b serve to attach the cross connector to the rod attachment elements and also to attach the rods to the rod attachment elements. The hook section 318 a includes an interior surface 324 a, preferably with a roughened surface. In FIG. 19 (A), the interior surface 324 a is shown with a number of teeth disposed thereon. Other roughened forms may also be using, including serrations, grit-blasted surfaces, textured coatings and the like. The post 316 a engages the post hole 320 a so that the base 312 a maintains a fixed, e.g., unrotating, position with respect to the housing 303 a as the screw 304 a is threadingly inserted into the hole 314 a in the base 312 a.
[0140] While the post and post hole maintain the relative positions of the rod attachment element housing and base, the entire rod attachment element may be rotated if desired about the screw 304 a. In particular, the longitudinal axis of rod attachment element 302 a need not be collinear with the longitudinal axis of rod attachment element 302 b. As seen in FIG. 20 (A), the rod attachment element 302 a may be rotated relative to the cross connector 306 , in the angular directions indicated by the arrows 323 and 323 ′.
[0141] The rod attachment elements' pivot, in the directions indicated by the arrows 323 and 323 ′, may be in part arrested by rounded edges 326 on the underside of the cross connector 306 . The rounded edges 326 may be disposed on one or both sides of the cross connector, and at one or two places on each side (to accommodate both directions 323 and 323 ′). The rounded edges may by configured to gradually increase the stopping force present as the rod attachment elements are pivoted to extreme angles.
[0142] As seen in FIG. 20 (C), the depression of hole 308 a may have a spherical shape 327 on which sits the screw head of screw 304 a, and the screw head itself may have a spherical shape. Thus, the screw head and screw may pivot adjacent and with respect to the depression of hole 308 a. To accommodate the screw shank movement during pivoting, an underside 325 of the hole 308 a may be tapered as shown. Due to these cooperating engaged surfaces, the rod attachment elements may be able to pivot along the directions shown by arrows 329 and 329 ′, as shown in FIG. 20 (B).
[0143] Referring to FIG. 21 (A)-(B), threading insertion of the screw 304 a causes the base 312 a to move in a direction indicated by arrow 328 a. Such displacement brings an angled surface 331 a of the base 312 a into engagement with the rod, securing the same against removal. The rod may be further secured by employment of an undercut 330 a which may form a distal end of the hook 318 a (see FIG. 21 (B)). Contact or locking points for the system are shown in FIG. 21 (B) by black dots.
[0144] In use, after the rods are attached to the installed pedicle screws, the rod attachment elements may be attached to the rods by first placing the rods in the rod-receiving channels within hook sections 318 a and 318 b. Then, posts 316 a and 316 b are placed in post holes 320 a and 320 b. The screws 304 a and 304 b are then at least partially tightened, and c-clips 310 a and 310 b may be disposed on the threads or grooves of screws 304 a and 304 b. As noted above, the use of posts ensures that angled surfaces 331 a and 331 b remain directed against the rods, securing the same from movement or removal. As above and in other embodiments, the system geometry, such as fine adjustments of widths and angles between components, may be adjusted prior to final screw tightening.
[0145] A related embodiment is shown in FIG. 22 , in which a cross connector 306 ′ is shown with a single slot 308 ′. In this embodiment, the single slot 308 ′ still allows a degree of width adjustment to achieve a desired distance between rods. The single slot 308 ′ can of course be provided for attachment to either rod attachment element. The method of use of the embodiment of FIG. 22 is analogous to the method of use of the preceding embodiment, except that the width adjustment is accomplished via only one screw, in particular, screw 304 b sliding in slot 308 ′.
[0146] FIGS. 23 (A)-(B) show another related embodiment. In this embodied system 340 , a cross connector 344 spans two rod attachment elements 342 a and 342 b. The rod attachment element 342 a includes a body 345 a with a throughhole 347 a defined therein and a biasing section or hook section 343 a. The rod attachment element 342 b has similar components, although the structure of rod attachment element 342 b may be entirely different if dictated by the requirements of the user.
[0147] A base 348 a is provided corresponding to each rod attachment element 342 a, the base 348 a including a threaded hole 349 a and an angled rod-locking surface 360 a. When constructed, a c-clip 352 a is disposed between the rod attachment element housing 345 a and the top of the base 348 a, for the same purpose as is described above. The rod attachment element 342 b may employ similar components.
[0148] The cross connector 344 has one or more holes defined therein, which are shown in FIG. 23 (B) as holes 362 a and 362 b. The holes may be elongated, as shown, to allow a set of screws 354 a and 354 b to occupy a variety of locations within the elongated hole, as may be required to accommodate different patient spinal dimensions. The holes 362 a and 362 b may be provided with depressions 363 a and 363 b, as seen in FIG. 23 (B), so that when a screw is inserted therethrough, the screw head may be made flush with or below the level of the cross connector 344 . The screws 354 a and 354 b serve to attach the cross connector 344 to the rod attachment elements 342 a and 342 b and also to attach the rods to the rod attachment elements, as will be shown.
[0149] The hook section 343 a includes an interior surface 356 a with a roughened surface. In FIG. 23 (A), the interior surface 356 a is shown with a number of teeth disposed thereon. Other roughened forms may also be using, including serrations and the like. As may be seen in FIG. 23 (A), the rod-contacting surface 356 a has a substantially cylindrical cross-section; at an extremal point on the circumference of this cylindrical cross-section, at the end nearest the hole 347 a, a flange 358 a may downwardly depend, the flange 358 a having an angled surface 351 a for sliding frictional engagement with an angled surface 360 a of the base 348 a. Unlike the previous embodiment, no post or post hole is employed in this embodiment; instead, the interaction and engagement between angled surfaces 351 a and 360 a maintain the fixed, e.g., relatively unrotated, position with respect to the housing and the base as the screw is threadingly inserted into the hole in the base. The screw, in this embodiment as well as others, may incorporate a distal thread section that is deformed or otherwise configured so as to prevent disassembly. The distal thread section or the threaded hole may alternatively or in addition incorporate a locking feature such as a polymer insert or the like.
[0150] As in the previously-described embodiment of FIGS. 19-21 , the screw head may be made spherical, and the depression appropriately configured as described in connection with those figures, to allow a degree of pivot to accompany this embodiment.
[0151] On the side of the flange 358 a opposite that of the surface 351 a, an undercut 359 a may be formed (see FIG. 24 ), which assists in the securing of the rod to the rod attachment element. The flange may form a flexible hinge, allowing the hook section to be snap-fit around the rod.
[0152] As in the previous embodiment, the entire rod attachment element may be rotated if desired about the screw 354 a. In particular, the longitudinal axis of rod attachment element 342 a need not be collinear with the longitudinal axis of rod attachment element 342 b or with the cross connector 344 .
[0153] In a similar way as noted above in connection with FIGS. 19-20 , the rod attachment elements' pivot angle, in the plane parallel to the cross connector 344 , may be in part arrested by rounded edges 346 on the underside of the cross connector 344 . The rounded edges 346 may be disposed on both sides of the cross connector, and at two places on each side (to accommodate both clockwise and counter-clockwise). The rounded edges may be configured to gradually increase the stopping force present as the rod attachment elements are pivoted to their extreme angles.
[0154] Contact or locking points for the system are shown in FIG. 24 by black dots.
[0155] In use, after the rods are attached to the installed pedicle screws, the rod attachment elements may be attached to the rods by first placing the rods in the rod-receiving channels within hook sections 343 a and 343 b. Then base 348 a and 348 b are threaded onto screws 354 a and 354 b such that surfaces 351 a and 360 a, as well as 351 b and 360 b, are adjacent. The screws 354 a and 354 b are then tightened, and c-clips 352 a and 352 b maybe disposed on the threads or grooves of screws 354 a and 354 b. In an alternative embodiment, the cross-connector system may be assembled, or partially assembled, prior to attachment of the rod attachment elements to the rods.
[0156] Referring to FIGS. 25 (A)-(B), an embodiment is shown with certain similarities to prior-described embodiments, although the rod attachment mechanism is different.
[0157] In this embodied system, a cross connector 370 spans two rod attachment elements 368 a and 368 b. The rod attachment element 368 a includes a body 369 a with a throughhole 384 a defined therein and a biasing section or hook section 371 a. The rod attachment element 368 b has similar components, although the structure of rod attachment element 368 b may be entirely different if dictated by the requirements of the user.
[0158] The cross connector 370 has one or more holes defined therein, which are shown in FIG. 25 (B) as holes 382 a and 382 b. The holes may be elongated, as shown, to allow a set of screws 380 a and 380 b to occupy a variety of locations within the elongated hole, as may be required. The holes 380 a and 380 b may be provided with a depression, as in the prior embodiments, so that when a screw is inserted therethrough, the screw head may be made flush with or below the level of the cross connector 370 . The screws 380 a and 380 b serve to attach the cross connector 370 to the rod attachment elements 368 a and 368 b and indirectly also assist in the attachment of the rods to the rod attachment elements, as will be shown.
[0159] The hook section 371 a includes an interior surface 374 a with a roughened surface. In FIG. 25 (A), the interior surface 374 a is shown with a number of teeth disposed thereon. Other roughened forms may also be using, including serrations and the like. As may be seen in FIG. 25 (A), the rod-contacting surface 374 a has a substantially cylindrical cross-section; at an extremal point on the circumference of this cylindrical cross-section, at the end nearest the hole 384 a, a flange 376 a may downwardly depend. On the side of the flange 376 a opposite the rod-contacting surface, the flange 376 a may incorporate a projection 377 a. On the side of the flange 376 a adjacent the rod-contacting surface, the flange 376 a may incorporate an undercut 379 a. The undercut 379 a assists in securing the rod to the rod attachment element; in particular, the flange may form a flexible hinge, allowing the hook section to be partially snap-fit around the rod. FIG. 26 (A) shows a perspective cross-sectional view of this embodiment. The snap-fit is enhanced, or in some cases may be supplanted, by the action of the screw on the flange. In particular, as the screw 380 a is inserted through hole 382 a and further threadingly inserted into hole 384 a, a distal end 378 a of the screw 380 a contacts the projection 377 a and forces the same towards the rod. As the projection 377 a is forced in that direction, so is the undercut 379 a, and the undercut 379 a further contacts and surrounds the rod, and secures the same against removal.
[0160] No base need be employed in this embodiment. As in the previously-described embodiments, the screw head may be made spherical, and the depression appropriately configured as described in connection with those figures, to allow a degree of pivot (prior to final screw tightening) to accompany this embodiment.
[0161] In a similar way as noted above in connection with FIGS. 19-20 and 23 , the rod attachment elements' pivot angle, in the plane parallel to the cross connector 370 , may be in part arrested by rounded edges 372 on the underside of the cross connector 370 . The rounded edges 372 may be disposed on both sides of the cross connector, and at two places on each side (to accommodate both clockwise and counter-clockwise). The rounded edges may be configured to gradually increase the stopping force present as the rod attachment elements are pivoted to their extremal angles.
[0162] Contact or locking points for the system are shown in FIG. 26 (B) by black dots.
[0163] In use, after the rods are attached to the installed pedicle screws, the rod attachment elements may be attached to the rods by first placing the rods in the rod-receiving channels within hook sections 371 a and 371 b. In many procedures, for this embodiment and for the others, a rod attachment element is attached to one rod, and the system is partially assembled. The width between the cross-connector is then accommodated by modification of the cross-connector and/or one or more rod attachment elements. A rod attachment element is secured to the second rod, and a final screw tightening may then occur. Then screws 380 a and 380 b are installed such that their distal ends deflect projection 379 and undercut 377 such that the undercut is forced against the rod, securing the same against movement.
[0164] Another embodiment of the invention is shown in FIGS. 27-30 . Referring in particular to FIGS. 27 (A)-(B), a system 390 is shown with two rod attachment elements 392 a and 392 b. Within each is defined a substantially cylindrical opening 398 a and 398 b for receipt and securing of a rod. The cylindrical openings may further include a serrated portion 400 a and 400 b with the same purpose as above, to assist in the securing of a rod. The rod attachment elements 392 a and 392 b further incorporate threaded holes 418 a and 418 b for threading insertion of rod-locking screws 396 a and 396 b. The rod-locking screws 396 a and 396 b have threads 426 a and 426 b disposed thereon. The rod attachment elements 392 a and 392 b further incorporate first and second bars 394 a and 394 b. The bar 394 a may extend directly out from the rod attachment element 392 a, while the bar 394 b may be vertically displaced a distance d from rod attachment element 392 b via diagonal section 412 b. Of course, in an alternative embodiment, rod attachment element 392 a may incorporate the vertically-displaced bar, or both may have vertically-displaced bars, where the amount of vertical displacement differs and/or is in opposite directions.
[0165] Each bar may have a through-hole defined therein. In FIG. 27 (B), the bar 394 a has through-hole 422 , and the bar 394 b has through-hole 420 . One or both through-holes may be elongated to accommodate a range of widths between the rods. In FIG. 27 (B), the through-hole 422 is shown elongated.
[0166] A bar clamping screw 402 having threads 406 holds the bars in a secure fashion via a nut 404 . The nut 404 includes a base section 423 through which is defined a threaded hole 424 . Depending upwardly from the base section 423 are two projections 414 a and 414 b. The projections 414 a and 414 b, which may vary in number, are received within the elongated hole 422 of the bar 394 a and serve to prevent the nut 404 from turning when the screw 402 is threadingly inserted.
[0167] The construction as described above allows a number of degrees of freedom to be obtained by the system 390 (these degrees of freedom may all be removed by final screw tightening—or one or more may remain “free”—such as to allow a degree of motion after implantation). FIG. 28 (A) shows arrows 416 a - 416 d, which indicate a degree of rotational freedom about an axis defined by the longitudinal axis of the screw 402 . An arrow 417 indicates a degree of translational freedom due to the elongated hole 422 . FIG. 28 (B) shows another rotational degree of freedom enjoyed by the system 390 , this degree of freedom transverse to the plane defined by the bars. The degree of freedom indicated by arrows 430 and 432 is afforded by the construction of the system 390 as indicated in FIG. 28 (C) and FIGS. 29 (A)-(B).
[0168] As seen in FIG. 28 (C) and FIG. 27 (B), a bottom surface 437 of a head 435 of screw 402 may be constructed to be substantially spherical, and the same may rotationally engage a spherical taper 421 at the top of the hole 420 . In the same way, the bottom of the hole 420 may be provided with a spherical taper 427 , and the same may rotationally engage a spherical taper 425 at the top of the hole 422 . The hole 420 may itself incorporate a wall 439 having a taper as indicated by lines 436 and 438 of FIG. 28 (C).
[0169] In other words, to further assist in providing the degree of freedom indicated by arrows 430 and 432 , the bottom of the bar 394 b, and the top of the bar 394 a, may be provided with mating spherical tapers so that one may be slidingly rotated on top of the other, as indicated in FIGS. 28 (C) and 29 (A). In many procedures, the degrees of freedom may be used to orient a device in a proper position and then the screw 402 may be threadingly tightened, locking the system in that position, as shown in FIG. 29 (B).
[0170] Contact or locking points for the system are shown in FIG. 30 by black dots.
[0171] In use, after the rods are attached to the installed pedicle screws, the rod attachment elements may be attached to the rods by first placing the rods in the rod-receiving channels defined by surfaces 398 a and 398 b. Then screws 396 a and 396 b are installed such that their distal ends deflect projection 410 and undercut 408 such that the undercut is forced against the rod, securing the same against movement. The bars are then positioned such that the screw 402 may extend through the hole in each. The nut 404 is then positioned such that the screw 402 may be threadingly inserted into the same, with the projections 414 a and 414 b inserted into the hole 422 to arrest rotational movement of the nut. Of course, in an alternative embodiment, the bars may be secured together first, and the same later attached to the rods.
[0172] In all of the above-described embodiments, where descriptions are provided for a group of elements suffixed by the letter ‘a’, a similar description may apply for the group of elements suffixed by the letter ‘b’; however, in all cases, a different type of group of elements may also be employed. There is no requirement that the same elements be employed. For example, a cross-connector system may employ two different rod attachment elements of entirely different type, if dictated by the requirements of the user. Whether the rod attachment elements are of the same or of differing types, the way in which the same couple to the rods may differ. One may couple at a different angle than the other. One may couple in a dynamic way, while the other couples in a static way. One may couple in a reversible fashion, while the other couple irreversibly. They may attach to different size rods, including rods of different lengths or diameters or both. The materials of construction of the rod attachment elements may differ. The bars may attach to the rod attachment elements at virtually any angle, and as noted may be pre-attached or integral therewith.
[0173] Further, in all of the above-described embodiments, various types of locking screws may be employed to protect against disassembly. Such locking screws may include polymer inserts, deformed or other high-resistance threads, or other types of locking mechanisms. The heads of the screws may incorporate insertable or removable fills or inserts so as to prevent contamination from entering a portion of the head where engagement with a tool may occur. In this way, follow-up adjustments and removal procedures may be made more convenient.
[0174] The rods described above may be of the type disclosed in U.S. patent application Ser. No. 11/362,366, filed on Feb. 23, 2006, entitled “Systems and methods for stabilization of bone structures” and incorporated by reference in its entirety herein.
[0175] The materials used in construction of all of the components are typically biocompatible and may be metal, such as titanium, although rigid plastics may also be employed.
[0176] Components disclosed above may be employed in various combinations.
[0177] Each rod attachment element may further include a hydraulic or pneumatic component, e.g., a hydraulic assembly that compresses the clamp portion to grip a corresponding rod. Other devices conveying a mechanical advantage to improve the gripping force may also be employed, such as cams, gear assemblies, and the like.
[0178] While the invention has been described in the context of spinal fusion, the same may be employed in dynamic systems, and indeed may include dynamic elements either in the cross-connector or as parts of the stabilization rods to which the rod attachment elements connect. Embodiments of the invention may also be employed in various other systems, such as facet replacement or facet augmentation systems. | A spinal cross-connector for connecting two stabilization rods installed in a patient's spine is provided. The cross-connector includes novel rod attachment elements dynamically connected together by connector elements. The cross-connector provides multi-dimensional adjustability for easy and accurate installation with full lock-down. | 0 |
This application is a Continuation-In-Part under 35 U.S.C. 1.53(b) of U.S. Ser. No. 08/992,448 filed Dec. 17, 1997, now abandoned.
FIELD OF THE INVENTION
The present invention relates to a process for decreasing the acidity and corrosivity of crudes and crude fractions containing petroleum acids.
BACKGROUND OF THE INVENTION
Many petroleum crudes with high organic acid content, such as whole crude oils containing naphthenic acids, are corrosive to the equipment used to extract, transport and process the crude, such as pipestills and transfer lines.
Efforts to minimize naphthenic acid corrosion have included a number of approaches. Examples of such technologies include use of oil soluble reaction products of an alkynediol and a polyalkene polyamine (U.S. Pat. No. 4,647,366), and treatment of a liquid hydrocarbon with a dilute aqueous alkaline solution, specifically, dilute aqueous NaOH or KOH (U.S. Pat. No. 4,199,440). U.S. Pat. No. 4,199,440 notes, however, that the use of aqueous NaOH or KOH solutions that contain higher concentrations of the base form emulsions with the oil, necessitating use of only dilute aqueous base solutions. U.S. Pat. No. 4,300,995 discloses the treatment of carbonous materials particularly coal and its products such as heavy oils, vacuum gas oil, and petroleum residua, having acidic functionalities, with a quaternary base such as tetramethylammonium hydroxide in a liquid (alcohol or water). Additional processes using bases such aqueous alkali hydroxide solutions include those disclosed in Kalichevsky and Kobe, Petroleum Refining With Chemicals, (1956) Ch. 4, and U.S. Pat. Nos. 3,806,437; 3,847,774; 4,033,860; 4,199,440 and 5,011,579. Publications WO 97/08270, WO 97/08271 and WO 97/08275 published Mar. 6, 1997, collectively disclose treatment with overbased detergents and Group IA and IIA oxides and hydroxides to decrease acidity and/or corrosion. Certain treatments have been practiced on mineral oil distillates and hydrocarbon oils (e.g., with lime, molten NaOH or KOH, certain highly porous calcined salts of carboxylic acids suspended on carrier media). Whole crude oils were not treated.
U.S. Pat. Nos. 2,795,532 and 2,770,580 (Honeycutt) disclose processes in which "heavy mineral oil fractions" and "petroleum vapors", respectively are treated, by contacting "flashed vapors" with "liquid alkaline material" containing, inter alia, alkali metal hydroxides and "liquid oil" using mixture of molten NaOH and KOH as the preferred treating agent, with "other alkaline materials, e.g., lime, also employed in minor amounts." The treatment of whole crudes or fractions boiling at 1050 plus ° F. (565 + ° C.) is not disclosed; only vapors and condensed vapors of the 1050 minus ° F. (565 - ° C.) fractions, that is, fractions that are vaporizable at the conditions disclosed in '532 are treated. Since naphthenic acids are distributed through all crude fractions (many of which are not vaporizable) and since crudes differ widely in naphthenic acid content the '532 patent does not provide an expectation that one would be able to successfully treat a broad slate of crudes of a variety of boiling points or to use bases other than NaOH and KOH.
U.S. Pat. No. 2,068,979 discloses a method for preventing corrosion in a petroleum still by adding calcium naphthenate to petroleum to react with and scavenge strong free acids such as hydrochloric and sulfuric acids to prevent corrosion in distillation units. The patent makes no claims with respect to naphthenic acids, which would have been formed when the strong acids were converted to salts. Patents have disclosed, inter alia, the addition or formation of calcium carbonate (Cheng et al, U.S. Pat. No. 4,164,472) or magnesium oxide (Cheng et al, U.S. Pat. Nos. 4,163,728 and 4,179,383, and 4,226,739) dispersions as corrosion inhibitors in fuel products and lubricating oil products, but not in whole or topped crude oil. Similarly, Mustafaev et al. (Sb. Tr. Azerb. Inst, Neft. Khim. (1971) 64-6) reported on the improved detergency and anticorrosive properties of calcium, barium, and zinc hydroxide additives in lubricating oils. Calcium hydroxide (Kessick, Canadian Patent 1,249,760) has been used to aid in separation of water from heavy crude oil wastes. U.S. Pat. No. 3,994,344 (Friedman) discloses the use of low molecular weight polyethylenimine to treat crudes. However, the resulting polyamine with acid groups attached is dissolved in the oil.
There is a continuing need to develop methods for reducing the acidity and corrosivity of whole crudes and fractions thereof, particularly residua and other 650 + ° F. (343 + ° C.) fractions. Applicants' invention addresses these needs.
SUMMARY OF THE INVENTION
The present invention provides for a method for decreasing the acidity of an acidic crude oil by contacting a starting acid-containing crude oil with an effective amount of a crosslinked polymeric amine to produce a treated crude oil having a decreased acid content and a crosslinked polymeric amine having acid groups attached thereto. The crosslinked polymeric amine with acid molecules attached to it, which is insoluble in the crude, can be isolated from the crude, e.g., by filtration or centrifugation, and regenerated by displacing the acids.
The present invention may suitably comprise, consist or consist essentially of the elements disclosed and may be practiced in the absence of an element not disclosed.
DETAILED DESCRIPTION OF THE INVENTION
Some whole crude oils contain organic acids such as carboxylic acids that contribute to corrosion or fouling of refinery equipment. These organic acids generally fall within the category of naphthenic and other organic acids. Naphthenic acid is a generic term used to identify a mixture of organic acids present in petroleum stocks. Naphthenic acids can cause corrosion at temperatures ranging from about 65° C. (150° F.) to 420° C. (790° F.). Naphthenic acids are distributed through a wide range of boiling points (i.e., fractions) in acid containing crudes. The present invention provides a method for broadly removing such acids, and most desirably, from heavier (higher boiling point) and liquid fractions in which these acids are often concentrated. The naphthenic acids may be present either alone or in combination with other organic acids, such as phenols.
Whole crude oils are very complex mixtures in which a large number of competing reactions may occur. Thus, the potential for successful application of a particular treatment or process is not necessarily predictable from the success of other treatments or processes.
The present invention may be used in applications in which a reduction in the acidity would be beneficial and in which oil-aqueous emulsion formation and large solvent volumes are not desirable. The decrease in acidity typically, is evidenced by a decrease in the neutralization number of the acidic crude or a decrease in intensity of the carboxyl band in the infrared spectrum at about 1708 cm -1 of the treated (neutralized) crude.
The concentration of acid in the crude oil is typically expressed as an acid neutralization number or total acid number (TAN), which is the number of milligrams of KOH required to neutralize the acidity of one gram of oil. It may be determined according to ASTM D-664. Typically, the decrease in acid content may be determined by a decrease in the neutralization number or in the intensity of the carboxyl band in the infrared spectrum at about 1708 cm -1 . Crude oils with total acid numbers of about 1.0 mg KOH/g and lower are considered to be of moderate to low corrosivity. Crudes with a total acid number of 0.2 or less generally are considered to be of low corrosivity. Crudes with total acid numbers greater than 1.5 are considered corrosive.
The crudes that may be used are any naphthenic acid-containing crude oils that are liquid or liquifiable at the temperatures at which the present invention is carried out. Typically the crudes have TAN of 0.2 to 10 mg KOH/g. As used herein the term whole crudes means unrefined, undistilled crudes.
The contacting is typically carried out at a temperature from ambient temperature to 150° C., with narrower ranges suitably from about 20° C. to 150° C., preferably 30° C. to 150° C.
Corrosive, acidic crudes, i.e., those containing naphthenic acids alone or in combination with other organic acids such as phenols may be treated according to the present invention.
The acidic crudes are preferably whole crudes. However, acidic fractions of whole crudes such as topped crudes and other high boiling point fractions also may be treated. Thus, for example, 500° F. (260° C.) fractions, 650 + ° F. (343 + ° C.) fractions, vacuum gas oils, and most desirably 1050 + ° F. (565 + ° C.) fractions and topped crudes may be treated.
In the present invention the crude is contacted with an effective amount of a crosslinked polymeric amine. Typically, these are solid at starting reaction temperatures. Examples of suitable compounds include polyethylenimine, polyallylamine and polyethylene piperazine. Crosslinking may be carried out as known in the art such as by treatment with peroxides or irradiation and produces a molecule of high molecular weight. In instances in which the monomer has been polymerized by a free radical mechanism, copolymerization with a suitable amount of difunctional monomer (e.g., divinyl benzene) produces a crosslinked polymeric amine. Polyethyleneimine and polyallylamine also may be crosslinked by reaction with a dihalide, e.g., 1,2-dichloroethane or 1,5-dibromopentane. The material is typically added as a solid, which also may include a solid-in-liquid slurry, solid-in-water or solid-in-organic liquid slurry. Addition should be in a molar ratio effective to produce a neutralized or partially neutralized crude oil. Neutralization may be in whole or partial as desired and thus molar ratios of amine groups to acid groups can vary within broad ranges to effect the desired reaction. Typically from 0.1 to 20, more preferable 0.5 to 10, most preferably 1 to 5, may be used.
Some crudes themselves contain a sufficient amount of water, but typically water addition facilitates the reaction particularly if the crosslinked polymeric amine is dry.
After reaction with the acidic functionalities in the crude oil, the crosslinked polymeric amine with acids attached to it, which is insoluble in the crude, can be isolated from the crude, e.g., by filtration or centrifugation. This is unlike prior art processes using low molecular weight (e.g., less than 600) since these are soluble in the crude and cannot be separated from it. Then the crosslinked polymeric amine may be regenerated and the acids recovered. Regeneration may be accomplished by displacing the acids via treatment with carbon dioxide in a suitable dispersant such as an aromatic hydrocarbon or with ammomia. The regenerated crosslinked polymeric amine may be recovered and recycled to treat additional acid containing crudes.
The formation of a crude oil-aqueous (i.e., either water-in-oil or oil-in-water) emulsion tends to interfere with the efficient separation of the crude oil and water phases and thus with recovery of the treated crude oil. Emulsion formation is undesirable and a particular problem that is encountered during treatment of naphthenic acid-containing crudes with aqueous bases. An additional benefit of the treatment is the absence or substantial absence of emulsion formation.
Suitable polymeric amines may be purchased commercially or synthesized using known procedures. In solid form, they may be in the form of a powder or a composite, sized particle or supported on a refractory (ceramic) matrix.
Reaction times depend on the temperature and nature of the crude to be treated, its acid content, but typically may be carried out for from less than about 1 hour to about 20 hours to produce a product having a decrease in acid content.
The present invention may be demonstrated with reference to the following non-limiting examples.
EXAMPLE 1
Crosslinking Polyallylamine
The reaction apparatus was a stirred vessel, equipped with a reflux condenser and having a capacity of 1 liter. 60 ml of water and 33.7 g of polyallylamine hydrochloride were put into the reactor and stirred until the polymer was completely dissolved. 14.4 g of solid sodium hydroxide were added slowly. 240 ml of n-octane and 600 mg of surfactant (Span 65) were added, followed by 22.6 g of 1,2-dibromoethane.
The mixture was stirred at 97° C. for 24 hours. The polymer was separated, treated with 5% aqueous NaOH, until AgNO 3 test showed no Cl - . Then it was washed with water until neutral, dried in vacuo and extracted with methanol in Soxhlet until no more polymer was extracted. Then it was dried in vacuo and weighed 20 g.
EXAMPLE 2
Neutralization of Acid Crude
The reaction apparatus was a stirred vessel equipped with a reflux condenser and having a capacity of 250 ml. 50.0 g of Bolobo 2/4 crude, having an acid number of 7.3 mg KOH/g, measured by infrared, were put into the reactor. 4.3 g of crosslinked polyallylamine, prepared according to Example 1, were added. The temperature was brought to 100° C. and the mixture was stirred for 5-6 hours. Infrared examination showed no reaction. Another 4.3 g of crosslinked polyallylamine were added and the mass was stirred at 100° C. for 24 hours. Infrared examination showed no reaction.
37.5 g of the above reaction mixture were put into an identical reactor and 1.9 g of water were added. Neutralization occurred rapidly. Infrared examination showed that the band at 1708 cm -1 , due to carboxylic acids, decreased as compared to untreated Bolobo 2/4. A small sample of the liquid was centrifuged to separate solids from it. Titration of the liquid with KOH according to ASTM D-664 gave a total acid number of 1.2 mg KOH/g. Untreated Bolobo 2/4 had a total acid number of 7.3 mg KOH/g. Therefore, treatment with polyallylamine had removed 83% of the naphthenic acids.
The infrared spectra of the untreated and treated crude were identical in the region around 1600 cm -1 indicating that the polyallylamine did not dissolve in the crude. If it had dissolved, a band at around 1570 cm -1 would have appeared. The solid was separated from the treated crude by filtration with suction, then washed repeatedly with toluene to free it of oil, then it was dried in vacuo. Infrared examination showed that a band about 1570 cm -1 was more intense than in unused polyallylamine, indicating the presence of carboxylate groups combined with the polymer.
EXAMPLE 3
Regeneration of Polyallylamine with CO 2
1.5 g of used polyallylamine with naphthenic acids attached (i.e., polyallylamine partly neutralized with naphthenic acids) to it, isolated and dried as described in Example 2, were put into an autoclave with a capacity of 300 ml. 75 ml of toluene and 5 g of solid carbon dioxide were added, then the autoclave was closed, heated to 80° C. and kept there for 24 hours. After cooling, the solid was separated by filtration and dried in vacuo. Toluene was removed from the filtrate by distillation in a Rotavap. The distillation residue weighed 1.3 g. Examination by infrared showed an intense band at 1708 cm -1 , due to carboxylic groups, indicating that the acid had been removed from the polyallylamine.
100 mg of distillation residue were analyzed by high-performance liquid chromatography, using aminopropylated silica gel as adsorption material. The analysis showed presence of naphthenic acids ranging in molecular weight from 300 to greater than 750. The average enrichment factor based on starting Bolobo 2/4 was 1.8 g, i.e., the acid content of the distillation residue was 1.8 times the acid content of Bolobo 2/4.
EXAMPLE 4
Regeneration of Polyallylamine Using Ammonia
The reaction apparatus was a stirred glass reactor with a capacity of 150 ml. 1.5 g of crosslinked polyallylamine with naphthenic acids attached to it, isolated and dried as described in Example 2, were put in the reactor. 50 ml of toluene and 141 g of 30 wt % ammonium hydroxide were added, then the mixture was stirred at room temperature for 24 hours. Then the solid was separated by filtration through a frit and washed with toluene. The combined filtrates consisted of two phases. The aqueous phase was discarded. The organic phase, after filtration to remove some solid particles, was evaporated to dryness. The residue weighed 0.27 g. Analysis by high-performance liquid chromatography, using aminopropylated silica gel as adsorbent, showed acids ranging in molecular weight from 250 to greater than 750. The average enrichment factor compared to untreated Bolobo 2/4 was 6.7.
EXAMPLE 5
Neutralization of Bolobo 2/4 Using Crosslinked Polyallylamine
The purpose of this experiment was to obtain polyallylamine loaded with a large amount of naphthenic acids to study its regeneration. The reaction apparatus was a stirred reactor with a capacity of 500 ml and equipped with a reflux condenser. 250 g of Bolobo 2/4, having an acid number of 7.3 mg KOH/g, determined by infrared spectroscopy, were put into the reactor. 2.14 g of crosslinked polyallylamine, prepared as described in Example 1, and 12.5 ml of water were added. The mixture was stirred at 100° C. for 6 hours. After cooling a small amount was centrifuged. The liquid was analyzed by infrared spectroscopy. The band at 1708 cm -1 , due to carboxyl groups, was 22% less intense than in untreated Bolobo 2/4.
The reactor contents were diluted with 750 ml of toluene and filtered through a frit. The solid was washed repeatedly with toluene and dried in vacuo. It weighed 5 g.
EXAMPLE 6
Regeneration of Polyallylamine Using CO 2
The reaction apparatus was a 300 ml autoclave. 1.5 g of polyallylamine partly neutralized with naphthenic acids and isolated as described in Example 5, were put into the autoclave with 75 ml of toluene and 5 g of solid CO 2 (dry ice).
The autoclave was rapidly closed and heated at 80° C. with stirring for 24 hours. After cooling, the solid was separated by filtration through a frit. The liquid, consisting mostly of toluene, was evaporated. The evaporation residue weighed 0.44 g. Examination by infrared spectroscopy showed an intense band at 1708 cm -1 , due to carboxyl groups. Another sample of evaporation residue was analyzed by high-performance liquid chromatography, using aminopropylated silica gel as adsorbent. Naphthenic acids with molecular weights ranging from 250 to greater than 750 were present. The average enrichment factor, based on starting Bolobo 2/4, was 19. The total content of acids was 82%.
EXAMPLE 7
Neutralization of Cyclopentyl-Acetic Acid
The system consisted of 1.8 g of cyclopentyl-acetic acid dissolved in 98.2 g of Tufflo white oil. 10 mls were put into a stirred reactor similar to that used in Example 2. 0.6 g of crosslinked polyallylamine, prepared as described in Example 1, were added. The mixture was stirred at room temperature for 6 hours. Infrared showed no change in the band at 1708 cm -1 due to carboxyl groups. 0.5 g of water were added and the mixture was stirred at room temperature overnight. Infrared examination showed that the band at 1708 cm -1 , due to carboxyl groups, had disappeared.
EXAMPLE 8
Neutralization of Bolobo 2/4
The reaction apparatus was a 200 ml flask, equipped with stirrer and reflux condenser. 50 g of Bolobo 2/4, having a total acid number of 7.3 mg KOH/g, 4.34 g of polyallylamine, crosslinked as described in Example 1, and 2.5 ml of water were put into the flask. Then the flask was brought to 100° C. and kept there for 6 hours. After cooling, the solid was separated by centrifugation. Titration of the oil according to ASTM D-664 gave a total acid number of 2.3 mg KOH/g. Examination by infrared showed that the band a 1708 cm -1 , attributed to carboxyl groups, was 29% as intense as in untreated Bolobo 2/4.
EXAMPLE 9
Neutralization of Bolobo 2/4
The reaction apparatus was a 200 ml flask, equipped with stirrer and reflux condenser. Into the flask was added 100 g of Bolobo 2/4, having a total acid number of 7.3 mg KOH/g, 4.3 g of crosslinked polyallylamine, prepared as described in Example 1, 5 ml of water. The flask was heated at 100° C. for 6 hours. After cooling, the solid was separated by centrifugation. Titration of the oil according to ASTM D-664 gave a total acid number of 3.1 mg KOH/g.
EXAMPLE 10
Neutralization of Gryphon Crude Oil
The reaction apparatus was a stirred reactor with a capacity of 500 ml and equipped with a reflux condenser. 150 g of Gryphon crude, having an acid number of 4.2 mg KOH/g, determined by infrared spectroscopy, were put into the reactor. 6.4 g of crosslinked polyallylamine, prepared as described in Example 1, and 7.5 ml of water were added. The mixture was stirred at 90° C. for 6 hours. After cooling the mixture was filtered through a coarse glass frit to remove the polyallylamine. The liquid portion was then centrifuged to remove water. Titration of the oil with KOH according to ASTM D-664 gave a total acid number of 0.5 mg KOH/g. Therefore, treatment with polyallyamine had removed 88% of the naphthenic acids. | The invention relates to processes for treating acidic crudes or fractions thereof to reduce or eliminate their acidity by addition of effective amounts of crosslinked polymeric amines. The process has utility for crude processing. | 2 |
FIELD OF THE INVENTION AND THE RELATED ART STATEMENT
1. Field of the Invention
The present invention generally relates to a sewing machine-driving apparatus and, in particular, it is concerned with a sewing machine-driving apparatus which permits a process for forming a double chain stitch seam or a covering chain stitch seam by a double chain stitch sewing machine or a covering chain stitch sewing machine. More particularly, it is concerned with a sewing machine-driving apparatus capable of forming a first seam at an end of cloth in the above-stated process.
2. Description of the Prior Art
In the conventional method for driving the double chain stitch sewing machine or the covering chain stitch sewing machine using two or more needles, it is generally well known to control the sewing machine to stop so that its position of stoppage may coincide with a predetermined position, i.e. a needle-up position or a needle-down position.
However, a technology relating to a sewing machine-driving apparatus as will be disclosed by the present invention has not heretofore been known. According to the present invention, the first seam can be made uniform by driving the sewing machine in a rotational direction reverse to that of the usual sewing operation during a time period starting from the needle-up position and ending with the needle-down position of the first stitch of the sewing start.
In the following paragraphs, an explanation will be made with reference to the appended drawings to a manner of forming a starting stitching seam in the above-stated conventional driving apparatus for the double chain stitch sewing machine or the covering chain stitch sewing machine using two or more needles.
FIG. 4 is a schematic view showing an arrangement generally employed for a conventional sewing machine-driving apparatus together with the sewing machine itself, and FIG. 5 shows a block diagram of the sewing machine-driving apparatus of FIG. 4.
As shown by FIG. 4, the sewing machine 1, having a position detection device 6, is driven by a motor 3 through a belt 2. The operator carriers out a stitching operation by operating a pedal 5 with his or her foot to actuate a control device 28 for controlling the motor 3 which drives or stops the sewing machine 1. As shown in FIG. 5, the operation of the pedal 5 is sensed by a pedal sensor 8. Pedal sensor 8 generates a driving command 9 when operator steps down on the pedal 5 by his or her toe and generates a thread-cutting command 10 when the operator returns the pedal 5 back by his or her heel. The driving command 9 is fed to a speed control unit 12 which rotates the motor 3 to drive the sewing machine 1 at a speed which corresponds to the driving command 9. When the pedal 5 is returned to a neutral position, the driving command 9 in interrupted. When the driving command 9 is interrupted, the position control unit 14 issues a command to the speed control unit 12 for stopping the motor 3 to the speed control unit 12 so that it may stop at a position which is being perceived by the needle position detection device 6, and the needles stop at a predetermined position.
After, driving the sewing machine 1 to complete the stitching operation, stopping it at the predetermined position and then stepping the pedal 5 back to the heel side to issue a thread cutting command 10 (as previously described), a thread cutting operation control unit 15 starts to energize an electromagnetic solenoid or a known air valve (omitted from the illustration), which is included in a thread cutter mechanism 16 of the sewing machine 1 to carry out the thread cutting operation in compliance with a predetermined sequence.
The foregoings are the exemplified arrangements employed in the generally well known micro-computer-implemented sewing machine-driving apparatus.
Next, a detailed known procedure for forming the first stitching seam to be carried out at the start of the stitching operation will then be described referring to FIGS. 6-10, using the conventional double chain stitch sewing machine or the covering chain stitch sewing machine, which employs, for instance, a couple of needles.
FIG. 6, is a schematic view of the generally well known double chain stitch or covering chain stitch sewing machine. As shown by this figure, when a pulley 24 of the sewing machine 1 is rotated by the motor through a belt, stitching needles 7 carry out a reciprocating movement while piercing through a cloth in response to the rotation of the pulley 24. Synchronously with this reciprocating movement, a looper 25 carries out an oscillating movement along an elliptic locus in a horizontal plane beneath the cloth. As shown by FIGS. 6 and 9, needle threads 26 are threaded through eyes of the stitching needles 7 while a looper thread 27 is inserted (has run) through the looper 25.
In the following paragraphs, a process for forming the first stitch at the start of the stitching operation will then be described in detail referring to FIGS. 7-10, using the conventional double chain stitch sewing machine or the covering chain stitch sewing machine, which employs, for instance, a couple of needles.
In FIG. 7, there is shown a mode of thread crossing between the stitching threads 26, indicated as black thread, and the looper thread 27, indicated as white thread. FIG. 7 is obtained at the time of forming a first stitching seam of the normal double chain stitch.
However, the usually intended crossing between the stitching threads and the looper thread can never be formed at the first stitch. At least one of the stitching threads at the first stitch will escape as indicated by the broken line, falling to form the seam; if the sewing machine is driven by the conventional sewing machine-driving apparatus,
The above-stated process will be described in more detail referring to FIGS. 9 and 10, wherein FIG. 9(A) depicts a state of these components after the stitching needles 7 pause at a needle-up position and a thread cutting operation is performed. When the pulley 24 is rotated in the same direction as that of the normal stitching operation, the stitching needles 7 begin to move from this state to scoop or catch the looper thread 27 at the first stitch as shown by FIG. 9(B). The looper 25 retreats as indicated by a white arrow to a state shown by FIG. 9(C), and then the looper 25 advances again to scoop the needle threads 26 which form loops at a state shown by FIG. 9(D). Whne a state shown by FIG. 9(E) is reached, the looper 25 advances, the looper thread 27 begins to tighten the stitching thread 26. Then, at a second stitch depicted by FIG. 9(F), the looper thread 27 and the needle thread 26 engage with the looper 25, but the stitching needle 7a at the left side of the figure does not actually scoop the looper thread 27 and thus does not form a seam. On the other hand, the other stitching needle 7b, which is at the right side of the figure, solely scoops the looper thread 27. And hence, in this state of FIG. 9(F), a pseudo seam is formed which is different from the normal seam. The stated mode is schematically shown also in a plan view of FIG. 10, viewed from the upper side.
As has been described, the conventional double chain stitch or covering chain stitch sewing machine employing a couple of stitching needles cannot form an intended normal seam at the first stitch of the seaming start. Thus, in order to form the intended double chain stitch seam or covering chain stitch seam throughout the entire seaming line from the start, the conventional sewing machine requires much labor in additionally stitching the first stitch in double and has a problem of failing to make the finished product look good.
OBJECTS AND SUMMARY OF THE PRESENT INVENTION
The present invention intends to solve the above-mentioned problem inherent in the conventional apparatus, and has, as its object, a provision of a sewing machine-driving apparatus capable of forming an exactly intended double chain stitch seam or covering stitch seam at the very first stitch of the stitching start.
In accordance with the present invention, in the sewing machine-driving appararus for driving a sewing machine, which has a thread cutter means, a position detection device for detecting a needle position, a motor for driving the sewing machine and a control device for controlling said sewing machine and motor,
said control device comprises;
a speed control unit, a position control unit, a thread cutting operation control unit and a stitch-start control unit; wherein
said speed control unit controls rotating direction and rotating speed of said motor in response to a driving command by an operator or in response to the input of a reverse driving command,
said position control unit controls the position of the needles of said sewing machine in response to a signal from said position detecting device issued at its stoppage in a manner that the needles may pause at a constant height,
said thread cutting operation control unit actuates said thread cutter mechanism of said sewing machine in response to the input of a thread cutting command,
said stitching start control unit comprises a reverse driving control unit, and
said reverse driving control unit issues, in response to a driving command after the actuation of said thread cutter mechanism, a reverse driving command to said speed control unit in a manner that said motor drives said sewing machine in a direction reverse to that of a usual stitching operation until said position detection device detects a needle-down position.
Said reverse driving control unit may preferably be arranged to operate only when a driving command is issued after the actuation of said thread cutter mechanism, and said position detection device detects a needle-up position.
Said motor or said sewing machine may further comprise, a speed detection unit capable of generating a plurality of signals during one rotation thereof.
Said signals issued from said speed detection unit are to be counted by a counter provided in said reverse driving control device. Said counter senses the rotation angle of said motor by counting the signals issued from said speed detection unit using the signal issued from said position detection unit as a reference. Thus, said motor may be rotated to drive said sewing machine in a direction reverse to that of the usual stitching only for a previously determined angle.
Said sewing machine-driving apparatus may further comprise a delay circuit which permits the usual stitching operation of said sewing machine in accordance with said driving command, after a lapse of a predetermined time period after the reverse driving at the start of the stitching operation.
The sewing machine-driving apparatus built in accordance with the present invention is capable of
1) stopping the sewing machine at the needle-up position, and
2) rotating the motor in a direction reverse to that of the usual sewing operation in response to the step-down of the pedal for a limited time period between the completion of the thread cutting operation and a time point when the needles reach their needle-down position, thus
3) enabling the stitching needles to reach their lowest points without scooping the looper thread at the first stitch of the start of the stitching operation in the double chain stitch sewing machine or the covering chain stitch sewing machine.
Hence, the undesirable insufficient engagement between the stitching threads and the looper thread will not occur. In addition, the looper thread will not interfere with the stitching threads during the entire process of ascending from their lowest points in the subsequent forward rotation.
Therefore, the stitching needle can surely scoop the looper thread during the subsequent process of forming the first stitch when the stitching needles descend again. By doing so, the apparatus can form the intended seam at the first stitch at the start of the stitching operation.
While the novel features of the present invention are set forth particularly in the appended claims, the invention, both as to organization and content, will be better understood and appreciated, along other objects and features thereof, from the following detailed description taken in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view showing a general arrangement of a sewing machine driving apparatus built in accordance with the present invention and a sewing machine.
FIG. 2 is a block diagram of a sewing machine driving apparatus built in accordance with the present invention.
FIG. 3(A), FIG. 3(B), FIG. 3(C), FIG. 3(D), FIG. 3(E) and FIG. 3(F) are schematic views each representing a mode in a sequential process of forming the first stitch of the sewing start in the double chain stitch or covering chain stitch sewing machine when driven by a sewing machine machine driving apparatus built in accordance with the present invention.
FIG. 4 is a schematic view showing a general arrangement of the conventional sewing machine driving apparatus and a sewing machine.
FIG. 5 is a block diagram of the conventional sewing machine driving apparatus.
FIG. 6 is the partly-cut out schematic side view illustrating an example of the conventional double chain stitch or covering chain stitch sewing machine.
FIG. 7 is the schematic view showing the normal seam to be formed by the conventional double chain stitch or covering chain stitch sewing machine.
FIG. 8 is the schematic view showing a conventional double seam.
FIG. 9(A), FIG. 9(B), FIG. 9(C), FIG. 9(D), FIG. 9(E) and FIG. 9(F) are schematic views each representing the mode in a sequential process of forming the first stitch of the sewing start in the double chain stitch or covering chain stitch sewing machine when driving by the conventional sewing machine machine driving apparatus.
FIG. 10 is the plan view of FIG. 9(F).
It will be recognized that some or all of the Figures are schematic representations for purposes of illustration and do not necessarily depict the actual relative sizes or locations of the elements shown.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the following paragraphs, a preferred embodiment of the present invention will be described with reference to the attached drawings, wherein the same reference symbols and numerals, as those used in above discussion made with reference to the conventional apparatus, are used for designating the same or similar components, and some of their descriptions are omitted here.
FIG. 1 is a schematic view showing a general arrangement of the sewing machine driving apparatus according to an embodiment of the present invention together with the sewing machine itself, FIG. 2 is a block diagram of the embodiment of the sewing machine driving apparatus. FIG. 3(A) through FIG. 3(F) are schematic views showing a relationship between movements of the stitching needles and that of the looper, when the double chain stitch or covering chain stitch sewing machine is driven by a sewing machine-driving apparatus of the embodiment of the present invention.
As shown in FIG. 1, the sewing machine 1, having the position detection device 6, is driven by the motor 3 through the belt 2. An operator carries out a stitching operation by operating the pedal 5 with his or her foot to actuate a control device 4 for controlling the motor 3. And the motor 3 drives the sewing machine 1 in response to the step-down operation of the pedal 5 and stops it when the pedal is returned to its neutral position. When the motor 3 is stopped, the control device serves to control the stitching needles 7 of the sewing machine in response to a signal issued from the position detection device 6 so that the needles 7 may always pause at a constant height.
Next, the operation of the control device 4, in particular, of the above-mentioned sewing machine-driving apparatus will be described with reference to FIG. 2.
In addition to the components already discussed with reference to the explanation of the control device 28 in the conventional driving apparatus, the control device 4 includes a stitch start control unit 17 composed of a reverse driving control unit 17-1 coupled with a first holding means 18 through and AND gate 17-2. The reverse driving control unit 17-1 includes a first change-over control means 11, a second holding means 19, a second change-over control means 20, a reverse driving command means 21, a counter 22 and a delay circuit 23.
The operation of the pedal 5 by the operator is sensed by the pedal sensor 8 which generates the driving command 9 and the thread-cutting command 10. When the operator steps down on the pedal 5 with his or her toe, the driving command 9 is issued. The driving command 9 is interrupted in response to the returning operation of the pedal 5 back to its neutral position. If the operator steps down on the pedal 5 with his or her heel, the thread-cutting command 10 is issued, but it is likewise interrupted in response to the returning operation of the pedal 5 back to its neutral position.
The driving command 9 is transmitted to the speed control unit 12 through the normally-closed first change-over control means 11. The speed control unit 12 commands the motor 3 to rotate at a speed in proportion to the depth of the pedal step-down. The speed control unit 12 also monitors a signal issued from the speed detection device 13 provided on the motor 3, and controls the rotation speed and the direction of the motor, 3. The motor employed in this embodiment is a DC brushless motor and the speed detection unit 13 issues two signals of 360 pulses/one rotation and of A and B phases offset each other by 90°, respectively.
When the pedal 5 is returned to its neutral position and the driving command 9 is interrupted, the position control unit 14 issues a command for reducing the speed of the motor 3 while monitoring a signal issued from the speed detection device 13, and controls the speed control unit 12 so that the sewing machine 1 may stop at positions where the stitching needles 7 pause at either one of their needle-up or needle-down position.
The thread cutting command 10 is fed to the thread cutting operation control unit 15. The thread cutting operation command 10 actuates the thread cutter mechanism 16 in the sewing machine by a known interior sequential control means (omitted from the illustration) under the conditions that the sewing operation is over and the needles are paused.
When the thread cutting operation control unit 15 operates, the first holding means 18 in a stitching start control unit 17 is set. Immediately after the first holding means 18 is set, the position detection device 6 issues a signal which indicates that the stitching needles are at their needle-up positions and the driving command 9 is issued, and the first change-over means 11 shifts to its open state by virtue of the AND gate 17-2.
Because of the above-mentioned arrangement, the motor 3 will not be driven by the driving command 9 at that time and, simultaneously, the second holding means 19 is set instead. The output of the second holding means 19 shifts the second change-over means 20 to its closed state and transfers a command of the reverse driving command means 21 to the speed control unit 12. The reverse driving command means 21 issues a command to the speed control unit 12 which permits the motor to rotate at a predetermined speed in a direction reverse to that indicated by the driving command 9. When the speed control unit 12 starts to rotate the motor 3, the counter 22 begins to count the signals issued from the speed detection device 13 using the signal from the position detection device 6 as a reference, and, when the counted value reaches a predetermined value, it resets the second holding means 19.
In this embodiment, the speed control unit 12 is arranged to reset the second holding means 19 at an angular position by 15° rotation of the pulley 24 after the detection of the needle-down position.
When the second holding means 19 is reset, it shifts the second change-over means 20 to its open state and simultaneously, resets the counter 22 and the first holding means 18. When the first holding means 18 is reset, the first change-over means 11 is also closed after a lapse of a certain time period, which is given for retardation or stoppage by a delay circuit 23. When the first change-over means 11 is closed, the driving command 9 is transmitted to the speed control unit 12 permitting the sewing machine to perform its usual driving/stopping.
As previously described, by employing the stated sewing machine-driving apparatus, the double chain stitch or covering chain stitch sewing machine with, for instance, a couple of stitching needles, is made to form an intended seam from the very first stitching.
Next, a detailed procedure for forming the first stitching seam will be described by referring to FIG. 3 and FIG. 6.
Since the sewing machine actually used with the exemplified sewing machine-driving apparatus is identical to the conventional one in its appearance, it will be described by referring to FIG. 6, which is a schematic view of the generally known double chain stitch or covering chain stitch sewing machine.
FIG. 3(A) indicates a state of the essential components just after the thread cutting operation when the stitching needles 7 are paused at their needle-up positions.
When a pulley 24 of the sewing machine 1 is rotated in a direction reverse to that of the usual sewing operation, the stitching needles 7 descend from the state shown by FIG. 3(A), passing aside the looper 25 along a path at the reverse side (front side of the paper) as indicated by solid black arrows in FIG. 3(B), and do not scoop the looper thread 27. Then, at the needle-down position shown in FIG. 3(C), the pulley 24 returns to rotate in the usual direction, causing the looper 25 and the looper thread 27 to move as indicated by white arrows. In a state indicated by FIG. 3(D), the looper 25 scoops the needle thread 26, and the operation proceeds to complete the first stitch as shown by FIG. 3(E) without making the looper thread 27 cross the as shown by FIG. 3(E) threads 26 as shown by FIG. 3(E). This mode is more clearly appreciated if it is compared with the case of formation of undesirable pseudo stitch shown in FIG. 9(E) discussed with reference to the conventional apparatus. That is, contrary to the pseudo or inaccurate seam formed in the first stitch in the conventional apparatus of the case of FIG. 9(E), the stitching by the present invention apparatus forms an accurate seam from the start of seaming. That is, in the second stitch, the stitching needle 7a surely scoops the looper thread 27, as shown by FIG. 3(F), thus making the intended stable and accurate seam formed from the start of the resultant seam of the stitching operation.
Although the counter 22 of the embodiment is set to count the signals which are equivalent to the rotation angle of 15° of the pulley, a similar advantage will be obtained if the needle-up position or any other value including "0" is taken as reference, or the counter 22 is totally omitted.
In addition to this, the delay circuit 23 may likewise be omitted. Further, although the second holding means 19 of this embodiment is set by the driving command 9 at the time the first holding means 18 is set and, at the same time, the position detection device 6 issues the needle-up signal, the condition of "the time when the position detection device 6 issues the needle-up signal" may be omitted.
Although the present invention has been described in its perferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form may be changed in the details of construction and the combination and arrangement of parts and components without changing the spirit and the scope of the invention as hereinafter claimed. | A sewing machine-driving apparatus forms an accurate and stable seam at a first stitch in a conventional double chain stitch or covering chain stitch sewing machine. Its motor is controlled so as to drive the sewing machine in a direction reverse to that of the usual sewing operation for a limited time period between the completion of a thread cutting operation and a point of time when the sewing machine needles reach their needle-down position. Thus, the stitching needles reach their lowest points without scooping a looper thread at the first stitch; assuring the formation of a stable and accurate seam in the second stitch. | 3 |
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