Vehicle detector arrangement comprising at least one detector unit (8) comprising at least one sensor (47, 48, 49, 50), a transmission/reception unit (54), an energy supply unit and a control unit (51, 52, 53), whereby the energy supply unit comprises a solar cell module (3). The transmission/reception unit (54), the energy supply unit and the control unit (51, 52, 53) are accommodated in a housing (27, 28) and connected to the at least one detector unit (8), whereby the solar cell module (3) is secured to the outside of the housing (27, 28). As a result of what is thus autonomous functioning of the vehicle detector arrangement, it can be simply secured, for example, to a bridge (6), and complicated installation jobs for power supply and data transmission, for example to a traffic routing center, are avoided.

1. Field of the Invention
The present invention is directed to a vehicle detector arrangement including a sensor with a solar power supply.
2. Description of the Related Art
Vehicle detection, for example for determining speeds, for counting vehicles or for classification, among other things for traffic routing and traffic information systems, is becoming more and more necessary and desirable due to the increasing traffic density. A means for identifying vehicles is disclosed, for example, by German Patent Document DE 27 54 117 C2, whereby it is required that the vehicles be equipped with a reply module that is evaluated at specific read locations arranged in the roadway area. Both the equipping of vehicles with readable reply units as well as the arrangement of read stations in the roadway area are relatively complicated and cost-intensive.
The present invention is based on the object of proving a vehicle detector arrangement for practical everyday use. The inventive vehicle detector arrangement should be capable of acquiring a continuous and durable data base and make it available for evaluation in order to enable dependable traffic information and a traffic routing adapted to the increasing traffic density without having to be connected to an external power supply and to data transmission cables in a complicated way.
For typically achieving the object, the invention proposes that the transmission/reception unit, the energy supply unit and the control unit are accommodated in a housing and are connected to the at least one detector unit, whereby at least one solar cell module is arranged at the outside of the housing.
The inventive vehicle detector arrangement is a compact central unit that can be flexibly utilized, whereby the elements that can be combined for one or more detector elements are accommodated in a housing of, for example, plastic. Such a central unit can be arranged with a supporting structure at buildings, bridges and the like but can also be secured to carrier poles and the like. Due to the energy supply with a solar cell module and the transmission/reception means, the vehicle detector arrangement thus works autonomously and no complicated installation jobs are needed. The connection between the central unit and the at least one detector unit can likewise be mechanically produced with a carrier unit. Detector units can also be positioned completely separately from the housing and can be electrically connected to the central unit.
According to one proposal of the invention, the detector unitxe2x80x94one or more being providedxe2x80x94comprises at least one passive of infrared sensor. Advantageously, the electrical circuit can be such due to the employment of the passive infrared detector that only a minimal power consumption ensues. The at least one sensor element can be arranged in a separate housing, for example a cylindrical housing with a frontal lens cover. According to an especially advantageous proposal of the invention, a detector unit comprises a plurality of sensors, whereby sensors with post-pulse oscillation and sensors without post-pulse oscillation are combined. Advantageously, three sensors with post-pulse oscillation are combined with one sensor without post-pulse oscillation.
According to another advantageous proposal of the invention, the detector unit additionally or alternatively comprises radar sensors or, respectively, additionally or alternatively comprises microwave sensors. A further improvement of the acquisition properties is achieved by the inventive combination of sensors with post-pulse oscillation and without post-pulse oscillation or, respectively, by the use of different sensors.
From the point of view of optimum energy utilization, the invention proposes that the vehicle detector arrangement can be switched between an idle mode and an active mode. This switching ensues automatically, for example after acquisition of a specific minimum number of vehicles, after expiration of an acquisition-free time or the like.
It is advantageously proposed that the solar cell module is adjustable.
Since, in particular, a readjustment of the angle of inclination considerably improves the utilization of solar light, an automatic readjustment of the solar cell module can also be inventively provided.
A critical aspect of the inventive vehicle detector arrangement is an altogether beneficial current balance. A battery and a solar panel are respectively connected to a charge regulator. The battery and charge regulator are designed for a nominal 12 volts. The solar panel, for example, delivers 5 through 6 watts. The charge regulator is connected to a voltage converter that nominally supplies the following detector circuit with 6 volts. Such a circuit enables a power consumption of approximately 4.75 mA at 12 volts. The current balance exhibits a power consumption of a maximum of 36 mW for a detector unit. The dissipated power of the voltage converter lies at approximately 20%, i.e. approximately 9 mW. The charge regulator has an intrinsic consumption that lies at approximately 12 mW. It follows from the data that a buffer battery of only 6.6 Ah can guarantee operation for more than 40 days without current being supplied from the solar panel. The inventive vehicle detector arrangement thus works nearly autonomously and extremely imperceptibly due to the structure. One reason for this is in the PIR technology that is employed, this making use of long-wave infrared radiation that already exists and that every body emits above the absolute zero point (xe2x88x92273xc2x0 C.).Differing from other technologies, thus, energy need not be emitted and in turn received. Only already existing, natural radiation is received. Radiation contrasts are thereby identified, namely both positive as well as negative contrasts. The ambient temperature thus plays a negligible part because the thermal overall change in radiation is acquired, as a result whereof the detection is nearly independent of the radiation frequency or, respectively, of the wavelength. The radiation contrast, among other things, is a function of the size and of the emission factor of the surface of a vehicle moving in or through the acquisition area. For achieving adequately precise measured values, a wait is first carried out for a temporally stable measured value sequence before the actual measurement.
The principle of a detector unit for achieving the stated objective is based on the detection of a vehicle that moves in a travel direction through a plurality of spatially separate zones that form the acquisition region. These at least two zones derive due to the optical imaging of corresponding sensor elements with a suitable lens arrangement and the evaluation of the resulting sensor signals. The speed information can be acquired from the time that a vehicle requires in order to proceed from zone 1 to zone 2. The vehicle length is calculated from the identified speed and the dwell time of a vehicle in one of the zones. Advantageously, more than the acquired two zones are selected and sensors having post-pulse oscillation as well as sensors without post-pulse oscillation are utilized and the signals resulting therefrom are interpreted in order to be nonetheless able to output information to the control unit given deterioration of a detector function or even given outage of a sensor (thereby providing a redundancy of the measurement).
The intensity and time sequence of the radiation changes produced in this way can vary greatly due to weather conditions over the course of a day and of the year as well as depending on the traffic flow. The amplitudes and time sequences of the signals of each sensor element resulting therefrom are continuously identified and further-processed for control purposes. This control, for example, can influence the properties of the gain of the sensor signals or the response thresholds of the signal processing and is especially advantageous because both the amplifiers as well as the signal evaluation thereby work in an optimum range under all weather conditions and traffic situations and the detector unit supplies extremely reliable results.
The physical principle of the detection on the basis of the change in thermal emission is also especially beneficial because it allows detector units to be realized with an essentially extremely low power consumption given autonomous, solar-operated supply.
The same physical principle also allows detector units to be mounted to the side of the lane, so that the coverage area is directed onto the lane to be monitored obliquely from above. This situation is especially advantageous when no bridge structure is available for mounting the detector units.
Due to the selection and arrangement of the infrared sensors as well as of the following amplification and signal evaluation, vehicles that stand still in the coverage area over a longer time can also be detected in addition to moving vehicles in order, in particular, to have information about the traffic available in traffic jam situations as well.
The signal evaluation is also in the position to monitor the correct function of the detector unit and its individual component parts as well as to monitor the correct alignment of the detector unit with reference to the lane to be monitored and to output an appropriately encoded message to the control unit given the presence of a malfunction. On the basis of corresponding circuits, idle modes can, over and above this, be set, so that, for example, an information forwarding via the transmission/reception unit, particularly the radio modem, only ensues on the basis of specific parameters identified by the control unit. For example, transmission conditions can thus be set by program. The transmissions thereby ensue, for example, via the SMS (short message system) band of a mobile radio telephone network, proceeding to a traffic routing center.
Advantageously, the detector means comprises one detector per lane of the roadway surface to be monitored, this being arranged above the level of the roadway surface and traffic movement on the lane allocated to it being capable of being acquired therewith. As a result of the fact that each lane has a detector allocated to it, the exact acquisition of all of the traffic occurring on the roadway surface is possible, since each lane is designed for only one vehicle in terms of its width. Vehicles traveling simultaneously through a specific area of the roadway surface can thus also be individually acquired. Due to the arrangement of the detectors above the level of the roadway surface, the traffic occurring on each lane can be acquired disturbance-free. Reliable data in view of the traffic density can be acquired with a vehicle detector arrangement fashioned in this way, these data being advantageously utilized in the framework of a parking routing system or of a traffic jam monitoring system or the like.
It is possible to fashion the processing means of the inventive vehicle detector arrangement as a central unit to which all detectors of the vehicle detector arrangement are connected with a suitable cabling. As a result thereof, the outlay for processing and forwarding the data acquired by the detectors of the vehicle detector arrangement is considerably reduced.
The central unit can also be advantageously arranged above the level of the roadway surface. For protecting the central unit against vandalism or the like, it is advantageous to arrange this in a cylindrical metal container, particularly a steel container, that is closed at one side with a plastic dome. The risk of vandalism or the like is thus largely precluded in conjunction with the arrangement of the central unit above the level of the roadway surface.
The plastic dome can be advantageously fashioned of polyamide or polyester, whereby these plastics, on the one hand, exhibit the required mechanical strength but, on the other hand, are transmissive for radio waves or the like, so that an antenna of the central unit can be expediently arranged in the region of the plastic dome.
Given employment at a bridge structure, the detectors and the central unit can be respectively attached to a frame that can be attached at the outside of a bridge structure to a side rail. As a result thereof, the outlay for the mounting, repair and maintenance of the vehicle detector arrangement can be considerably reduced since the bridge structure is available as a work surface.
In order, given mounting, repair and maintenance jobs at the inventive vehicle detector arrangement, to reduce the risk that articles will fall from the vehicle detector arrangement onto the roadway surface, each frame of the inventive vehicle detector arrangement advantageously comprises a pivotable section that can be pivoted from a position arranged outside the side rail into a position arranged above the bridge structure. Significant portions of the mounting, repair and maintenance jobs can be implemented inside the side rail of the bridge structure, so that one can reliably prevent any articles from falling down onto the roadway surface or, respectively, onto the lane under the bridge structure. After the conclusion of the majority of the mounting jobs, the pivotable section of the frame must then merely be pivoted from its position arranged above the bridge structure into its position arranged outside the side rail and can then be subsequently brought to its ultimate installation position or secured thereat.
A firm attachment of the vehicle detector arrangement or, respectively, of the frame above the roadway surface at the bridge structure can be achieved when the frame is positively connected to the side rail over at least three web members of the side rail, whereby the frame should be advantageously connected to the side rail at two locations over the at least three web members of the side rail.
For correct positioning and for a fixed attachment, the frame should comprise two horizontal fastening arms projecting outside the side rail that are respectively firmly connected to the side rail at one end. As a result thereof, an attachment of the function unit can be achieved wherein this is arranged at the frame over the roadway surface without interposition of the bridge structure.
In an advantageous development, the frame comprises a vertical carrying rail that is secured to the ends of the two horizontal fastening arms that are spaced from the side rail.
Insofar as the frame has a carriage that is displaceable in a vertical direction at the carrying rail, it is possible to position the detectors and the central unit of the inventive vehicle detector arrangement at a side of the bridge structure in an arbitrary vertical position within a certain range, as a result whereof the accessibility of the vehicle detector arrangement for unauthorized persons can be considerably limited. Vandalism and other intentional damage, in particular, can thereby be precluded to the greatest possible extent.
The pivotable section of the frame can be expediently fashioned as swivel arm that has its one end pivotably and fixedly seated at the carriage and carries the detectors or, respectively, the central unit of the vehicle detector arrangement at its other end. As a result of such a fashioning, both a pivotable arrangement of the detectors or, respectively, of the central unit of the vehicle detector arrangement as well as an adjustable positioning thereof in a vertical direction can be realized in what is a comparatively uncomplicated way in technical-structural terms. Due to the pivotable arrangement, jobs arising during mounting or during maintenance can also be undertaken above the bridge structure, i.e. thus, over the bridge structure, which, on the one hand, reduces the risk to the assembly or, respectively, maintenance personnel and, on the other hand, substantially reduces the risk to traffic participants using the roadway surface below the bridge structure due to falling articles.
The vertical adjustment of the carriage seated which is displaceable in a vertical direction at the carrying rail of the frame can be implemented in a simple way with a lifting mechanism that can be plugged onto the vertical carrying rail and comprises a cable winch whose cable can be connected to the carriage and with which the carriage can be vertically moved until the pivot arm of the frame is arranged above an upper string piece of the side rail of the bridge structure. For potential mounting, maintenance or repair jobs at the central unit or at the detectors of the vehicle detector arrangement, the pivot arm can then be lifted with the lifting mechanism until it can be swiveled from its position arranged on the other side of the bridge structure above the roadway surface into its position arranged above the bridge structure. After this, the pivot arm can then be lowered with the lifting mechanism or, respectively, by paying out the cable winch thereof until it lies on the upper string piece of the side rail, as a result whereof a further protection of the pivot arm and, thus, of the detectors or, respectively, of the central unit derives in the position that has been assumed.
A fixed attachment of the pivot arm to the carriage and a possibility for pivoting the pivot arm with reference to the carriage that can be realized in a simple way when needed is enabled when the pivot arm is connected to the carriage with a swivel pin and a swivel boat, whereby the swivel boat can be withdrawn from its position that connects the pivot arm and the carriage and the pivot arm can then be pivoted around the pivot boat with reference to the carriage.
A firm attachment of the carriage and, thus, of the detectors or, respectively, of the central unit of the vehicle detector arrangement in a position lowered optimally far from the bridge structure and wherein the accessibility to the central unit or, respectfully, the detectors is considerably reduced is achieved when the carrying rail comprises an end stop for the carriage and a blocking means in its lower end region with which the carriage can be blocked at the lower end stop.
The longer the pivot arm is compared to the fastening arms, the central unit or, respectively, the detectors of the vehicle detector arrangement can be offset from the edge of the bridge structure toward the center thereof all the farther given required mounting, repair and/or maintenance jobs.
In order to prevent the frame from failing onto the roadway surface given damage to the side rail at the location at which the frame is provided, it is advantageous when each frame comprises a crash protection that is secured on the one hand, to the frame and, on the other hand, to at least one side rail post that is arranged between a lower string piece of the side rail and the bridge structure.


A two-stroke engine with an isolation chamber. The isolation chamber has a pressure-sensitive wall attached to or slidably mounted within the isolation chamber. The pressure-sensitive wall is substantially impervious to air, oil, and the fuels used in an internal combustion two-stroke engine. When the piston of the engine moves away from the crankcase, a vacuum is created in the crankcase. This draws the pressure-sensitive wall toward the crankcase within the fluid communication circuit, which movement of the pressure sensitive wall also pulls air into the intake side of the isolation chamber through a one-way valve or time induction mechanism. When the piston moves toward the crankcase, the increased pressure within the crankcase forces the pressure-sensitive wall away, fluidwise, from the crankcase and thus pushing air from the isolation chamber into the combustion chamber. The pressure-sensitive wall therefore is effective in preventing oil from flowing into the combustion chamber from the crankcase. Further, a modified piston having a lower oil ring precludes oil from being pushed by pressurized air from leaving the crankcase, squeezing past the piston, and reaching the transfer port and the exhaust port. Consequently, pollution is minimized in a two-stroke engine utilizing this novel design approach.

1. Field of the Invention
This invention relates to a two-stroke internal combustion engine, especially such an engine with a pressure-sensitive wall contained within a chamber for isolating the crankcase from the combustion chamber.
2. Description of the Related Art
In a conventional two-stroke internal combustion engine, the vacuum caused by a piston moving away from the crankcase draws a mixture of fuel, air, and oil into the crankcase through a one-way valve or timed induction mechanism such as a piston port or rotary valve. Increased pressure produced by the piston moving toward the crankcase forces the mixture of fuel, air, and oil into the piston cylinder on the side of the piston away from the crankcase and, therefore, into the combustion chamber, which is at the portion of the piston cylinder that is the most distant from the crankcase, because such carbureted fuel cannot escape through the one-way valve or a now closed induction mechanism.
The crankcase is used as a compressor. This requires the crankcase to have relatively close tolerances between the crank and the crankcase, itself. It is also required that the crankcase be sealed. These factors isolate the crankcase from any lubrication that may be in other parts of the engine. Therefore, a secondary lubrication system is necessary. However, any oil in the crankcase would readily be pushed into the combustion chamber. Therefore, to minimize the oil that is pushed into the combustion chamber, oil is continuously added to the crankcase, but only in small quantities. In conventional two-stroke engines this is accomplished either by oil injection or by utilizing fuel which has been pre-mixed with a suitable quantity of oil. But no matter how the lubrication is achieved, oil will be introduced into the combustion chamber and combusted. And during the combustion process, such oil creates considerable smoke and other pollution.
Additionally, when a traditional two-stroke internal combustion engine compresses the mixture of fuel, air, and oil (before the transfer ports open), some of the fuel and oil can go past the piston skirt and into the exhaust port unburned. This adds to hyrocarbon pollution of the atmosphere and limits the attainable crankcase pressure.
U.S. Pat. No. 4,248,185 of Eric Jaulmes employs a membrane 7 in the crankcase pump 1 of a two-cycle engine, but the sole purpose of that membrane 7 is to divide the crankcase pump 1 into two chambers 8 and 9. Chamber 8 contains the crankshaft 6 and the connecting rod 4 and would, therefore, also contain oil for lubrication. Since carbureted air passes through chamber 8 on its way to the piston cylinder 2, oil (whether pre-mixed with fuel or injected into the crankcase) would thereby be introduced into the piston cylinder 2. Pure air passes through chamber 9 to reach the piston cylinder 2; but because of the oil-containing carbureted air, the membrane 7 does not isolate the piston cylinder 2 from the oil in the crankcase. In the alternate embodiment of FIGS. 7 through 9, the carbureted air passes through chamber 9; and pure air goes through chamber 8. Thus, as explained in lines 25 through 28 of column 4, it is necessary to provide separate lubrication, i.e., lubrication could not be accomplished by oil pre-mixed with the fuel. The oil that would be separately added for lubrication would then travel with the air to the piston cylinder 2.
U.S. Pat. No. 5,291,866 of David R. Kosa applies to a Pulse Charger 40 which supplies air from the crankcase 24 of a four-cycle internal combustion engine to the intake system 18 of that engine. It is asserted that a baffle 120 between the crankcase 24 and the pulse charger 40 xe2x80x9caids in keeping any liquid from enteringxe2x80x9d the pulse charger and that an xe2x80x9cadditional oil separator 140 . . . may also be included in order to separate crankcase oil from the pulsed air charge prior to the pulsed air charge entering carburetor or fuel injection system 52 [which carburetor or fuel injection system 52 is placed between the pulse charger 40 and the intake system 18]. Oil separator 140 can be of the centrifugal type, the baffle type or any other type of separator known in the art.xe2x80x9d The baffle 120 and oil separator 140, however, attempt to remove oil from air which such oil has already infiltrated rather than precluding such oil from ever entering the air.
The supercharger in U.S. Pat. No. 3,672,172 of Gary L. Hammond appears to operate in a fashion rather similar to that of U.S. Pat. No. 5,291,866. xe2x80x9cTo avoid any undesired entrainment of oil in the supercharging air, an air-oil separator such as, for example, louvered baffle, wire mesh screen, loose packed metal shavings or the like, or combinations thereof, is employed [between the crankcase 26 or 122 and the inlet valve 12 or intake port 104]. The separator should not unduly restrict airflow but should trap entrained oil.xe2x80x9d In attempting to remove oil from air which such oil has already infiltrated rather than precluding such oil from ever entering the air, the devices of U.S. Pat. Nos. 5,291,866 and 3,672,172 do, however, necessarily limit airflow.
Some two-stroke internal combustion engines avoid introducing oil into the carbureted air by not using the crankcase as a pump. Instead, these engines utilize superchargers, which are heavy, expensive, and inefficient because the blower is always turning and putting a load on the engine even when there is no demand from the engine for fuel or air, i.e., when the transfer ports are closed.
The present invention utilizes the pressure and vacuum cycles created within the crankcase of a crankcase compression two-stroke internal combustion engine to force air into the piston cylinder, also termed the combustion chamber, of the engine. A flexible diaphragm, bellows, or floating piston is, though, utilized to isolate the air that travels to the combustion chamber from the crankcase. Therefore, no oil ever enters the combustion chamber.
As the piston moves away from the crankcase, a vacuum is created within the crankcase. This draws the flexible diaphragm, bellows, or floating piston within an isolation chamber toward the crankcase, creating a vacuum on the side of the diaphragm, bellows, or floating piston away from the crankcase and drawing a mixture of fuel and air (or plain air if either a fuel injection system that injects fuel into the combustion chamber is utilized or a charge former is between the isolation chamber and the transfer port) through a one-way valve or timed induction mechanism into the isolation chamber on the side of the diaphragm, bellows, or floating piston that is away from the crankcase.
When the piston moves toward the crankcase, the increased pressure pushes the diaphragm, bellows, or floating piston in the isolation chamber away from the crankcase. Because the mixture of fuel and air or pure air on the side of the diaphragm away from the crankcase cannot escape through the one-way valve or timed induction mechanism, such mixture of fuel and air or pure air is forced into the piston cylinder and, therefore, into the combustion chamber.
Such mixture of fuel and air or pure air is, therefore, pumped into the combustion chamber without ever being exposed to oil that lubricates the crankcase and without the use of a supercharger.
Preferably, the piston is designed with a full-length skirt around the entire perimeter of the piston and with at least one ring around the piston. This ring is placed so that it is always between all ports and the crankcase in order to preclude oil that is either maintained within and/or circulated through the crankcase from passing between the piston and the wall of the piston cylinder and thereby entering the exhaust port or the transfer port. (Oil in the exhaust port would be heated to such an extent that it would smoke or be pushed into the surrounding environment; oil in the transfer port would be pushed into the combustion chamber and create smoke during combustion which would then be exhausted to the surrounding environment.)

Two-stroke internal combustion engine with isolated crankcase


A blend of starch and a thermoplastic aliphatic-aromatic copolyester resin, at a specific gravity of greater than 1.0. In method form, the invention comprises supplying an aromatic-aliphatic based polyester, supplying starch and mixing the aromatic-aliphatic based polyester with the starch and introducing the mixture to a melt processing apparatus wherein the aromatic-aliphatic based polyester and starch are mixed and molded or extruded into a desired shape.

The present invention relates to blends of starch and aliphatic-aromatic based polyester resins, including a process for forming injection molded products from the blends of such materials. The blends find particularly utility as applied to the manufacture of molded chew toys for animals, although other extruded/molded products are available.
In U.S. Pat. No. 5,827,565 it is pointed out that most dogs enjoy chewing on a flavored object although preferences vary as to the hardness. Some dogs like to chew on very hard materials such as cow bones, nylon, while others prefer softer chews such as polyurethane or rubber. Some dogs, due to their age, may not be able to chew on very hard substances. Young dogs have insufficiently developed teeth, while old dogs may have diseased gums or may have lost some of their teeth.
T.F.H. Publications Inc., the owner of this application, has previously been awarded patent protection for an edible dog chew that is wholly digestible, nutritious and which maintains a texture or hardness that is individually adjustable by the application of heat to suit a wide variety of a dog""s preferences or needs. Such dog chews utilize a mixture containing primarily casein and are described in U.S. Pat. Nos. 5,200,212 and 5,240,720.
In U.S. Pat. No. 5,827,565 also owned by T.F.H. Publications, Inc.,there is disclosed a process for making a heat expandable dog chew comprised primarily of injection molding potato starch granules and an attractant. Attractants recited include chicken powder, liver powder, ham, turkey, beef and or fish. Natural vegetable additives such as spinach or carrots also may be added. The resultant mixture is molded under heat and pressure into a desired form, such as a dog bone. The dog bone so produced can be modified in texture or hardness by subsequent heating, preferably in a microwave oven.
In U.S. Pat. No. 6,126,978, which is a continuation-in-part of U.S. Pat. No. 5,827,565, and which is again owned by T.F.H. Publications, Inc., there is disclosed a dog chew having natural fruit flavor to increase the dog""s appetite for such chew. Such fruit flavored dog chew may also include natural food coloring to enhance the attractiveness of the chew to the dog owner. The food coloring may also correspond to the fruit flavor, and the dog chew disclosed therein may also embody a breath sweetener for a dog such as mint, spearmint, peppermint or wintergreen and may also include parsley. The preferred form of such edible chew maintained the basic ingredient of a heat-expandable starch, such as potato starch. Fruit flavoring may be added to the granules of a mixture of potato starch, water and calcium carbonate along with natural fruit flavorings.
Attention is also directed to the following U.S. Patents and copending applications, commonly owned by T.F.H. Publications Inc.: U.S. Pat. No. 5,476,069; U.S. patent application Ser. No. 08/923,070 filed Sep. 3, 1997 entitled xe2x80x9cVegetable Based Dog Chewxe2x80x9d now U.S. Pat. No. 6,093,427; Ser. No. 08/738,423 filed Oct. 25, 1997 entitled xe2x80x9cEdible Dog Chewxe2x80x9d now U.S. Pat. No. 5,827,565; Ser. No. 08/784,834 filed Jan. 17, 1997 entitled xe2x80x9cCarrot-Based Dog Chewxe2x80x9d now U.S. Pat. No. 5,941,197; Ser. No. 09/114,872 filed Jul. 14, 1998 entitled xe2x80x9cHeat Modifiable Edible Dog Chewxe2x80x9d now U.S. Pat. No. 6,180,161; Ser. No. 09/138,804 filed Aug. 21, 1998 entitled xe2x80x9cImproved Edible Dog Chewxe2x80x9d now U.S. Pat No. 6,126,978; Ser. No. 09/116,070 filed Jul. 15, 1998 entitled xe2x80x9cWheat and Casein Dow Chew With Modifiable Texturexe2x80x9d now U.S. Pat. No. 6,110,521; Ser. No. 09/116,555 filed Jul. 15, 1998 entitled xe2x80x9cHeat Modifiable Peanut Dog Chewxe2x80x9d now U.S. Pat. No. 6,093,441; Ser. No. 09/227,767 filed Jan. 8, 1999 entitled xe2x80x9cMethod of Molding Edible Starchxe2x80x9d now U.S. Pat. No. 6,159,516. In addition to such patents and applications, attention is also directed to the art cited in said patents and applications, as such art relates to the field of molded starch products.
In addition, the prior art has recently grown considerably to include a variety of other disclosures directed at flavored pet products. For example, U.S. Pat. No. 5,786,382 entitled xe2x80x9cUse of Valerian Plant and/or Root as a Scent-Attractant for Stimulating Canines and Felinesxe2x80x9d. This patent discloses the use of the herb/plant Valerian in all of its forms whether whole or in part, for use in food product, in such a manner that the natural aroma emitted by the Valerian plant will act as a scent/attractant for dogs and cats.
U.S. Pat. Nos. 4,985,964 and 5,007,879 entitled xe2x80x9cDog Chew Processing Methodxe2x80x9d disclose methods for processing cattle hoofs for use as a dog chew product.
U.S. Pat. No. 5,149,550 entitled xe2x80x9cMethods for Making Pet Chewsxe2x80x9d discloses that ligaments from cattle and other hoofstocks are rendered substantially free of fat and can be dried and hardened for use as a pet chew.
U.S. Pat. No. 5,407,661 entitled xe2x80x9cPet Chew Product Having Oral Care Propertiesxe2x80x9d discloses an edible pet chew product having a flexible cellular matrix in which is contained cellulosic fibrous material such as corn cob fractions which are described as having a mechanical cleansing function when chewed by a pet.
U.S. Pat. No. 5,635,237 entitled xe2x80x9cMethod of Manufacturing Substantially Pure Rawhide Pet Productsxe2x80x9d discloses a chew of pure rawhide utilizing twin screw extrusion with multiple heating zones and interchangeable extrusion dies.
U.S. Pat. No. 5,711,254 entitled xe2x80x9cDog Chew Toyxe2x80x9d discloses a chew toy for dogs formed of a length of composite rope having an inner core defined by strands of twisted threads of natural plant or synthetic fibers and a soft outer shell defined by a plurality of strands of soft cotton threads twisted about the inner core. The inner core is said to be less water absorbent than the outer shell to promote drying of the toy when wetted with dog saliva to inhibit bacteria growth.
U.S. Pat. No. 5,750,196 entitled xe2x80x9cProcess for Manufacturing Dog Chew Toys of Tire Sidewallsxe2x80x9d discloses the use of a dye to cut toy bases from sidewalls recovered from used tires.
Other earlier examples of such products are disclosed in U.S. Pat. No. 3,871,334 to Axelrod (nylon substrate containing liquid flavor and odor components) and U.S. Pat. No. 4,771,733 to Axelrod (polyurethane toy containing aqueous-based flavor and odor components). U.S. Pat. Nos. 4,557,219 and 4,513,014 to Edwards disclose the use of flavorings in a molded polyurethane chew objects.
Finally, attention is directed to U.S. Pat. No. 6,184,261, which discloses a foam that is the extrudate mixture that includes a biodegradable polymer, starch, talc, and a blowing agent. The biodegradable polymer may be poly(tetramethylene adipate-coterephthalate).
Accordingly, it is an object herein to improve further upon Applicants"" earlier disclosures regarding animal chews, to form a biodegradable animal chew from a thermoplastic polyesteramide and starch. Furthermore, it is also an object of the present invention to form a biodegradable animal chew wherein the polyesteramide component is present in distinct domains dispersed within a continuous starch phase.
A blend comprising an aromatic-aliphatic based polyester and starch. In method form, the invention comprises supplying an aromatic-aliphatic based polyester, supplying starch and mixing said aromatic-aliphatic based polyester with the starch and introducing said mixture to a melt processing apparatus wherein said aromatic-aliphatic based polyester and starch are mixed and molded or extruded into a desired shape.
As noted, the present invention comprises a blend composition formed from an aliphatic-aromatic copolyester and starch. Aliphatic-aromatic polyesters is reference to those theromplastic resins that are comprised of, in combination, one or more of an ester linkage, an aliphatic unit, and an aromatic unit, all covalently bonded to one another in the polymer chain.
Preferably, the aromatic-aliphatic polyester herein is a poly(tetramethylene adipate-co-terephthalate) resin, obtained under the tradename Eastar Bio(trademark) from Eastman Chemical Company, Kingsport, Tenn. Poly(tetramethylene adipate-co-terephthalate) is reportedly made by condensing 1,4-benzenedicarboxylic acid (an aromatic acid) with 1,4-butanediol and an aliphatic diacid. It can be appreciated therefore, that by adjusting the level of aliphatic to aromatic concentration, a variety of different aliphatic-aromatic type polyesters can be formed, with varying physical properties. In that regard, it is preferable that in the context of the present invention, an aliphatic-aromatic based polyester is employed that has the following general characteristics with respect to the starting materials preferably employed for manufacture:
Aliphatic Diacid Component: HOOCxe2x80x94(CH2)xxe2x80x94COOH
Glycol Component: HOxe2x80x94(CH2)yxe2x80x94OH
Aromatic Acid Component: HOOCxe2x80x94Arxe2x80x94COOH
wherein the values of x and y above are in the range of 4-20, preferably 4-10, and in a most preferred embodiment, x and y are equal to the value of 4-8. With respect to the aromatic acid component, preferably, the acid groups (xe2x80x94COOH) are attached in para configuration on the aromatic unit (terephthalic acid), however, other isomers are contemplated, such as isophthalic acid, which configures the acid groups in the meta configuration.
In the context of the present invention it is preferred that the level of aliphatic to aromatic content in the aliphatic-aromatic polyester is specifically controlled to provide thermoplastic behavior, with an identifiable crystalline melting point. In such fashion, preferably, the aliphatic-aromatic polyester does not contain an elastomeric soft segment, with one or more of the following characteristics: 1. a glass transition temperature that occurs below room temperature; or 2. a repeating unit such as HOxe2x80x94(CH2CH2O)nxe2x80x94H with a value of n therein being greater than or equal to 10; or 3. a number or weight average molecular weight itself of greater than 100-1000, at 1.0 increments therein. Alternatively, if such elastomeric soft segment is present, it is preferably present at a level less than or equal to 50% (wt) with respect to the crystalline and thermoplastic aliphatic-aromatic polyester noted above.
More preferably, the crystalline melting point of the aliphatic-aromatic copolyester is lower than the softening temperature of the starch to be blended herein. With that unique criterion, by setting the melt processing temperature of the extruder or injection molding machinery, to be used to facilitate blending, above the maximum softening temperature of the starch, one provides improved melt processing performance as it also helps insures plastication and dispersion of the aliphatic-aromatic copolyester within the starch extrudate.
Elaborating on the above, it should be noted that at temperatures above 90-120xc2x0 C. starch is known to become destructured. The term destructured means a starch which has been heat-treated above its glass transition temperature and melting points of its components so that the components are subjected to endothermic transitions to thereby produce a consequent disorder in the molecular structure of the starch granules. In that sense, the crystallinity of the starch is destroyed.
The starch used in the present invention is preferably a natural material extracted from various plants such as corn, potato, wheat, tapioca, and cereals. Starches are polysaccharide compounds which on hydrolysis produce sugars. Starch can include a mixture of linear components generally referred to as amylose, and branched components generally referred to as amylopectin. Amylose generally has a molecular weight of several hundred thousand, while amylopectin generally has a molecular weight in the order of several million. Starches containing 0 to 100% amylose or 0 to 100% amylopectin can be employed in the invention.
As used herein, starch should be understood to preferably include starches with a high amylopectin content sometimes called waxy starches, as well as chemically and physically modified starches, such as for example starches whose acid values have been reduced, starches in which the type and concentration of cations associated with the phosphate groups have been modified, ethoxylated starches, starch acetates, cationic starches, oxidated starches and cross-linked starches.
The preferred form of the dog chew of the present invention has as a basic ingredient, a potato starch product sold under the trademark PARAGON(trademark) IM 1010 by AVEBE of Veendam, The Netherlands. The PARAGON(trademark) IM 1010 product is sold in the form of thermoplastic granules which are molded into a desired shape. The weight contents of such pellets are about 70% potato starch, about 15% water (about 10% after the pellets are molded), about 5 to 10% calcium carbonate, and about 1 to 5% natural vegetable additives. Optionally, to such mixture is added a flavoring such as chicken powder, liver powder, ham, turkey, beef, and/or fish in the amount of 1 to 5% by weight. Natural vegetable additives such as spinach or carrots may also be added.
In accordance with the above preferred PARAGON(trademark) IM 1010, those skilled in the art will appreciate that an equivalent to the PARAGON(trademark) IM 1010 would also serve as a preferred embodiment. In that regard, the potato starch can be replaced with any other equivalent starch, such as wheat starch, and the calcium carbonate, being an inorganic salt, can be replaced with any suitable inorganic salt, such as potassium carbonate, etc.
The aliphatic-aromatic copolyester component of the present invention can be made present between about 0-99% by weight based upon the weight of starch used, and at 1% increments therein. Accordingly, the level of starch herein can be at least 1% by weight, 2% by weight, 3% by weight, up to a level of 99% by weight. Preferably, 1-50% (wt), 1-40% (wt) and 1-30% (wt) of aliphatic-aromatic copolyester is combined with starch to form the mixtures herein. Most preferably, 40-60% (wt) aliphatic-aromatic copolyester is employed, and in a most preferably embodiment the aliphatic-aromatic copolyester is present at a level of about 40%, +/xe2x88x9210%. The aliphatic-aromatic copolyester component is preferably dry mixed with the starch component, and that mixture is then molded into a desired shape.
As those skilled in the art will appreciate, an injection molding apparatus, which is one preferred melt processing and mixing apparatus, typically contains a hopper feed section, a barrel, and an output nozzle, including a plurality of heating zones in the barrel extending from the hopper section to the nozzle. In accordance with the present invention, it has been found preferable to maintain the temperature in the first zone adjacent to the hopper at a temperature of about 125xc2x0 F. More preferably, the first zone adjacent to the hopper is set in the range of about 50-175xc2x0 F. In an even more preferred embodiment, i.e. that situation wherein there is a first zone adjacent to the hopper, and a second zone adjacent to that first zone, the temperature of the first zone is set to about 125xc2x0 F., and the temperature of the second zone is set to between about 50-150xc2x0 F. In a most preferred embodiment, the temperatures of both the first zone and second zone are each set to about 125xc2x0 F.
These zone temperatures are most conveniently achieved by use of cooling coils placed about the barrel of the injection molding apparatus. These cooling coils are preferably made from copper tubing, and are cooled with circulating water.
In a particularly preferred embodiment, the following temperature profile is used to mold the aliphatic-aromatic copolyester/starch composition of the present invention: Zone 4 (closest to hopper)=125xc2x0 F.; Zone 3=125xc2x0 F.; Zone 2=175-350xc2x0 F.; Zone 1=275-375xc2x0 F.; Nozzle=275-350xc2x0 F. In addition, the bushing inside the mold is preferably set to about 325-425xc2x0 F. The mold temperature is preferably set at 35-65xc2x0 F.
As opposed to a more conventional practice of heating the barrel of the screw to melt the material in the zones proximate to the hopper, the temperature profile set forth above results in cooling the barrel in those zones thereby preventing overheating and burning of the aliphatic-copolyester/starch mixture. In addition, use of this preferred temperature profile does not result in a thorough melt based intermixing of the aliphatic-aromatic copolyester component with the starch component. Rather, the molded aliphatic-aromatic copolyester/starch article contains discrete aliphatic-aromatic copolyester domains dispersed within a continuous starch phase. In the context of the present invention, such discrete aliphatic-aromatic copolyester domains may be visually distinct from the continuous starch phase, or readily viewable via optical microscopy.
In the context of the present invention, and as noted, a preferred aliphatic-aromatic copolyester is Eastar Bio(trademark) copolyester, which has a crystalline peak melting point of about 108xc2x0 C., and an inherent viscosity of about 1.10. In that regard, it is worth noting that such melting point is lower than the recommended processing temperature of the Paragon(trademark) 1010 IM, which falls within the range of 160-185xc2x0 C.
Furthermore, in accordance with the present invention, it has been found that the number of heat histories applied to the subject blend uniquely effects the appearance of phase separation in the final product. For example, when the aliphatic-aromatic copolyester are starch and combined and subjected to direct injection molding, one observes discrete domain formation as between the copolyester and starch, with the starch as the continuous phase. Nonetheless, such product provides a uniquely smooth and continuous surface appearance, thereby rendering it suitable for the manufacture of injection molded products.
Alternatively, the subject blend herein may be first exposed to melt blending by the step of extrusion, followed by injection molding. In this fashion, the use of two heat histories results in a reduction in the quantity of discrete domain formation that occurs in direct injection molding. Therefore, in the context of the present invention, one can uniquely consider the use of a single heat history (e.g., direct injection molding) or a double heat history (extrusion compounding followed by direct injection molding) to regulate and control the size and amount of domain formation that appears in the final product, while maintaining excellent surface properties, in the sense that the surface is smooth with appealing visual qualities.
Furthermore, it should be noted that regardless of the heat history applied, the products of the present invention are uniquely compatible, in the sense that the mechanical properties of the blend formulation provides sufficient strength, ductility and flexibility to serve, in preferred embodiment, as an animal chew toy. In addition, the present invention is preferably of a non-foamed configuration, does not rely upon the use of an added blowing agent, or added compatibilizing agent, and in that sense, the molded products herein are substantially solid plastic products with a specific gravity of greater than 1.0.
As those skilled in the art will appreciate, the product may be molded into any of a variety of shapes, including a bone, rod, ring, disk, and the like. Accordingly, in broad aspect, although injection molding is preferred, any other type of molding process is contemplated. For example, the aliphatic-aromatic copolyester/starch composition of the present invention is suitable for compression molding as well as other thermoplastic processing techniques available in the art. In that regard, the aliphatic-aromatic copolyeseter/starch mixture herein can be prepared by extrusion techniques.
In accordance with the present invention, flavorings may optionally be added to the aliphatic-aromatic copolyester/starch composition during the molding process. Natural flavorings are preferred. As will be appreciated by those skilled in the art, such flavorings may comprise both powders and liquids. The weight content of such fruit flavorings in the animal chew of the present invention may be preferably between about 0.1 weight percent and about 5.0 weight percent, but preferably fall in the range of 0.25-1.0 weight percent.
In addition, a food coloring may be added to the aliphatic-aromatic copolyester/starch mixture prior to molding to enhance the attractiveness of the chew. A natural food coloring is preferred. The weight content of such food coloring in the present invention may preferably be between about 0.05 weight percent and about 10 weight percent. More preferably, food coloring is set between 0.1-1.0 weight percent.
A fragrance may also be added to the aliphatic-aromatic copolyester/starch mixture prior to molding. The weight content of such a fragrance in the present invention may preferably be between about 0.1 weight percent and about 5.0 weight percent. In that regard, a preferred fragrance would include teatree oil.
The following examples are presented to further illustrate to persons skilled in the art how to make and use the invention and to identify presently preferred embodiments thereof. These examples are not intended as limitations, however, upon the scope of the invention, which is defined only by the appended claims. In each of the examples below, the product was melt mixed on injection molding equipment following the preferred processing conditions noted above. The products formed had excellent mechanical properties suitable for use in an animal chew toy product.

Blends of starch and aliphatic-aromatic based polyester resins


The visual appearance of undyed or unpigmented para-aramid fabric generally present in an article of clothing is restored by contacting the fabric with an aqueous dye solution or dispersion to dye the aramid fibrils present on the yarns. Use of a conventional washing machine is suitable in the fabric contact with the dye.

The present invention relates to a process for improving the natural appearance of an article of clothing, which comprises a yarn of para-aramid fiber. The process involves contacting undyed and non-pigmented yarn with an aqueous dye solution or dye dispersion wherein the process is particularly adaptable using a conventional washing machine.
An important use of aramid yarn is in the manufacture of articles of clothing and particularly articles of clothing employed where resistance to cuts or lacerations and/or protection from exposure to elevated temperatures.
Typically, the articles of clothing are made from para-aramid yarns, specifically poly (p-phenylene terephthalamide), however they may also be made from a combination of para-aramid yarns such as poly (p-phenylene terephthalamide) yarn known under the designation PPD-T and non para-aramid yarn such as isophthalamide known under the designation MPD-I. Other synthetic fibers, such as nylon and polyester, and organic fibers, such as cotton, may be present in the yarns of these articles of clothing.
However, difficulties and disadvantages arise with the use of undyed or unpigmented para-aramid yarn from an appearance standpoint.
Para-aramid fiber has a highly ordered fibrillar structure with a propensity for fibrillation attributable to the lack of lateral forces between macromolecules. As the para-aramid content of a fabric increases above 5 weight percent, the extent of potential fibrillation of the para-aramid fibers also increases and actual fibrillations can become more noticeable and objectionable. With the wear, abrasion and laundering that occurs as the fabric article is used over time, fabrics lose their aesthetic appeal.
Para-aramid fibers in general and in particular, poly(paraphenylene terephthalamide) (PPD-T) fibers, have molecular features of high crystallinity, a stiff molecular chain and high interchain bonding forces resulting in high tensile strength and high modulus. However, these molecular features which provide such outstanding physical properties also result in the para-aramid fibers being quite difficult to dye. This attribute of para-aramid fiber is generally discussed in U.S. Pat. No. 4,144,023 to Provost, U.S. Pat. No. 4,985,046 to Hartzler, and U.S. Pat. No. 5,232,461 to Ghorashi, wherein various dyeing processes are disclosed.
U.S. Pat. No. 4,144,023 discloses an improved dyeing process wherein wetted aromatic polyamide fibers are crimped and maintained moist before dyeing. U.S. Pat. No 4,985,046 discloses disadvantages of xe2x80x9cspun-inxe2x80x9d and xe2x80x9cstructure propxe2x80x9d methods of dyeing poly(paraphenylene terephthalamide) fibers and discloses a process wherein specially prepared fibers (acid treated or never dried) are contacted with an aqueous solution of a dye promoting species. U.S. Pat. No. 5,232,461 discloses dyeing poly(paraphenylene terephthalamide) fibers by heating them under high pressure.
None of the U.S. Patents discussed above relate to the problem of restoring the appearance of fibrillated aromatic polyamide fibers.
Treatment of a used or worn material to adjust the color with blueing agents is described in U.S. Pat. No. 2,424,778 to Tainsh. Blueing agents are described as generally being blue colors, pigments or dyes having generally a slight reddish tint. The desired whitening effect is produced as a result of the blue and red combining with the yellowish tint of the material to give a light grey or bluish grey which looks whiter and is more pleasing to the eye than the faint yellow coloring of the untreated material.
It is desirable to have a method to restore the appearance of an undyed or non-pigmented fabric containing para-aramid yarn when such fabric loses its appearance from wear in an article of clothing, from laundering or from weaving of the fiber.
The present invention is directed to a process for restoring the appearance of an article of clothing comprising a fabric made from yarns having undyed and non-pigmented para-aramid yarn segments having fibrils comprising the steps of:
(a) contacting the article of clothing with an aqueous dye solution or dispersion to dye the para-aramid fibrils, and
(b) drying the article of step (a).
The starting material in the present invention is typically an article of clothing made from para-aramid yarn which is not dyed or pigmented prior to its manufacture. However in normal wear of the clothing, the clothing appearance deteriorates due to abrasion and/or due to exposure to a hostile environment. Also appearance can deteriorate due to repeated laundering.
Preferred articles of clothing of the present invention include protective apparel including cut resistant protective apparel including gloves, aprons, sleeves and fire fighting equipment which, in many instances, are made solely from para-aramid fiber. In repeated use such as with gloves, the appearance can rapidly deteriorate without affecting the durability of the glove fabric.
Also a use for clothing made from undyed and non-pigmented aramid yarn is for fire fighting equipment outer garments. The clothing encounters abrasion through surface contact and becomes dirty through normal wearing including perspiration of the wearer or often due to contact with smoke, soot and in extreme cases due to corrosive chemicals. Accordingly, such outer garments are washed in conventional washing machines employing household detergents. It has been found with para-aramid fibers, repeated washings can cause the clothing to lose its new natural appearance.
Fibrillation of para-aramid yarn results in the unattractive appearance of the clothing. While soiling of individual fibers also occurs, it is considered that fibrillation is often the predominant reason for the negative appearance.
Illustratively, a reason for the loss of the look of a new fabric is thought to be due to a difference in the light reflectance of the fibrils which partially separate from the main filament. Since the fibrils have a much smaller diameter, they reflect light differently compared to the main filaments. The fabric surface begins to look lighter in shade with portions of the fabric of different shades due to the manner light is reflected. Additionally, with a combination of different yarns, such as a non-para-aramid yarn in addition to the para-aramid yarn, the amount of fibrillation can differ. Such difference affects the visual color appearance.
Although it is well known that para-aramid yarn is difficult to impart color by dyeing or pigmenting, nevertheless it has been discovered that fibrils of the para-aramid yarn readily absorb a dye. Therefore the present invention is directed to modifying the appearance of the fibrils by dyeing such that their color and reflection of light is similar to the unfibrilated yarn which accounts for the bulk of the cloth. Use of pigment also allows a modification of appearance of the fibrils. Most gloves are made by knitting spun yarn. A few gloves are made from cut and sew of woven cloth.
The dyeing or pigmenting operation is considered to primarily affect the fibrils with little or no effect on the unfibrillated para-aramid yarn.
Therefore, the present invention in a preferred embodiment allows the wearer to restore the appearance of the article of clothing in straightforward fashion using a conventional washing machine operating at normal operating conditions. The starting material for the article of clothing is a cloth made from a non-dyed or non-pigmented para-aramid yarn. However, in certain instances the content of para-aramid fiber may be small, i.e. less than 5 percent by weight of the clothing (ignoring any additional clothing liner). In preferred embodiments the para-aramid content can predominate and approach or be at a 100% concentration particularly where cut protection is important such as in gloves, aprons and sleeves.
Useful aramids are described in greater detail in U.S. Pat. No. 3,767,756 to Blades; U.S. Pat. No. 3,869,429, also to Blades and U.S. Pat. No. 4,144,023 to Provost. Other high strength, high modulus fibers are prepared by the process of U.S. Pat. No. 5,336,734. These fibers are prepared from aromatic polyamides containing divalent aromatic radicals in which the chain extending bonds of the radicals are substantially coaxial or parallel and oppositely directed and are connected by amide (xe2x80x94NHCOxe2x80x94) linkages. The radicals may also be linked by vinylene, ethynylene, azo or azoxy radicals. A portion of the aromatic radicals may be replaced with trans-1,4-cyclohexylene radicals.
Briefly, these fibers are typically prepared by extruding the polymer through orifices in a spinneret to form individual filaments which are combined to form continuous mulifilament yarns. These yarns may be plied or wrapped with other yarns and then knitted or woven into fabrics. Alternatively, if a spun staple fiber yarn is desired, these continuous multifilament yarns can be stretch broken or cut into staple fiber and spun into staple yarns using conventional cotton system processing techniques and then knitting or weaving those yarns into fiber. The continuous multifilament yarns can also be combined with other types of multifilament yarns to form a tow. The tow can then be cut to form staple fibers which are later spun into yarns and then into fabrics using known techniques.
An article of clothing can include a high content of non-para-aramid fibers. In one embodiment of this invention the garment contains para-aramid fibers which are poly (p-phenylene terephthalamide) (PPD-T) and poly (m-phenylene terephthalamide) (MPD-1).
The type of dyes which can be suitable in the present invention are varied and include cationic, disperse or acid dyes.
However cationic dyes are preferred where they are readily soluble in water. A dye dispersion is less preferred since for optimum results such dispersion generally needs to be added to water prior to any contact with the article of clothing.
The weight ratio of dye to weight of fabric to be colored can vary over wide ranges. Dilute dye concentrations can be employed such as 0.01% based on the weight of the fabric. However it is preferred to employ concentrations in a range from 0.02 to 0.1%. An upper concentration is not critical but generally will be not more than 1% by weight. Excessive dye concentrations are not desirable since excessive dye will be discarded. Also it is within the scope of the present invention to employ multiple dyeing steps. Illustratively, dilute dye concentrations below 0.01% can be employed with a series of dyeing steps to raise the total dye concentration to at least 0.01% based on the weight of the fabric.
Generally, the dilution of the dye in water which contains the article of clothing is not critical. Generally this dilution can be expressed as the amount of water to the weight of fabric. Suitable ratios of water to fabric can range from 3:1 to 100:1 by weight.
A factor which can influence the dyeing of the fibrils is the temperature of the water for the dye solution or dye dispersion. Generally a temperature of 40xc2x0 C. will be employed. An example of a suitable range is from 40 to 80xc2x0 C. Temperatures in the range of 55 to 65xc2x0 C. are preferred. Generally aqueous dye contact with the article of clothing will be at least 5 minutes, generally at least 10 minutes and more preferably 30 minutes. Use of a conventional washing machine can be employed.
In the process according to the invention it is not necessary to include dye assist agents in the dye solution. By dye assist agents, it is meant carriers or additional chemicals that are added to swell the fiber. Furthermore, the use of high pressure to assist in the uptake of the dye from the bath is not necessary and atmospheric conditions are preferred. Also, the use of a fluorescent agent, and particularly a blue fluorescent substance such as disclosed in U.S. Pat. No. 2,424,778 is not necessary and lies outside the scope of the present invention. Accordingly such substance lies outside the definition of a dye as employed in the present invention.
To illustrate the present invention, the following examples are provided.
All parts and percentages are by weight unless otherwise indicated. Also, all temperatures are in degrees centigrade. The color determinations were made using a Hunter Tristimulus Colorometer model D25M-9.
The color and shade depth for the various samples of fabric were determined by measuring the Hunter xe2x80x98Lxe2x80x99, xe2x80x98axe2x80x99, and xe2x80x98bxe2x80x99 values in the conventional manner. The xe2x80x98Lxe2x80x99 color component is a measure of the blackness or whiteness of the sample, while the xe2x80x98axe2x80x99 value is a measure of where the color of the sample is in the red to green range and the xe2x80x98bxe2x80x99 value is a measure of where the color of the sample is in the blue to yellow range.
In the following examples the natural color of gloves composed of 100% poly(p-phenyleneterephthalamide) (except for trim and cuffs) was restored. The treatment involved contacting the glove with an aqueous dye solution before final rinse cycle in a commercial laundering process. The natural golden color of the aramid fiber was regenerated under all water temperatures and a range of pH conditions. No dye assist agent was used in the process. After the dye contact with glove, the dye becomes non-fugitive. The treated gloves exhibited good crocking resistance-resists color transfer when rubbed. The appearance renewal process has no impact on the cut protection provided by gloves composed of the poly(p-phenyleneterephthalamide).
All gloves in the following examples were seamless knitted gloves composed of 100% poly(p-phenyleneterephthalamide) spun yarn. The cuff materials included rubber for elasticity and colored polyester thread for the overedge trim.

Process for restoring the natural appearance of para-aramid clothing


An oximeter diode-driving device has a diode, a transistor operative to controllably connect current to the diode, a current sensing resistor that senses at least part of the current, a feedback amplifier operative to control the connecting of current by the transistor according to the current sensed by the current sensing resistor, and an inductor disposed in series with the current sensing resistor. A method of driving a current through the diode of an oximeter includes driving a current through the diode by connecting the current to the diode, controlling the connecting using a feedback type amplifier, the feedback type amplifier having a current source that uses a current-limiting resistor, and adding phase lead to a current passing through the current-limiting resistor.

1. Field of the Invention
This invention relates generally to feedback control of oximeter diode drive currents and, more particularly, to eliminating oscillations due to diode cable reactances without degrading current control.
2. Related Work
A pulse oximeter is a type of blood gas monitor which non-invasively measures an amount of saturation of oxygen in the blood. The saturation of oxygenated blood may be determined from the differential absorptions for two plethysmographic waveforms measured at separate wavelengths. The two waveforms are typically produced by driving a visible red light-emitting diode (LED) and an infra-red LED to produce two lights that pass through a patient""s tissue, and then detecting the light on the same or an opposite side of the tissue using one or more photodetectors. The light-emitting LEDs are placed in a probe that is attached to the patient""s body in a preferred location for the particular application. Although most conventional oximeters use the red and infra-red LEDs, other devices such as surface emitting laser devices having different wavelengths may also be used, and the number of LEDs can vary according to the specific measurement application. For example, it is known to set a number of laser diodes to be equal to or than the number of blood analytes that are to be measured by the instrument. In the specific field of photoplethysmography, the light beams that are generated by the LEDs must be of sufficient intensity to illuminate the perfused tissue and also be of constant wavelength, since the light absorption of the monitored analyte varies as a function of wavelength.
The probe may be a sleeve or clamp that fits around a patient""s finger or earlobe. The LEDs are disposed in the probe, for example, to be positioned on one side of the patient""s finger. The probe is electrically connected to an LED drive circuit and to detection measurement and analysis apparatus via a cable of a given length.
The probe also has one or more photodetectors that detect the light, for example, received on an opposite side of the patient""s appendage from the LEDs. The received light of different wavelengths is converted into electrical signals by the photodetector. The signals are then electronically processed and analyzed to isolate signals representing a measurement of oxygen saturation of arterial blood.
Ideally, the current source for an oximeter LED simply drives current through the probe cable and into the LED without the current being affected by its transmission through the LED driver circuit and probe cable. However, the characteristics of the cable and LED affect the stability of the oximeter LED drive circuit. Large changes in voltage can occur across the probe cable when the LED turns on or off, where this LED switching can cause the oximeter LED drive circuit to experience oscillation as the LED current control circuit tries to keep up with the changing cable voltage. Therefore, when the diode is switched on and off, an oscillation current (ringing noise) may be superimposed on current flowing through the diode. This oscillation degrades current control, and affects accuracy and sensitivity of oximetry measurements. It is understood that the term xe2x80x9ccurrent sourcexe2x80x9d used herein refers to either or both of a sourcing or a current sinking configuration.
This oscillation problem exists because the op-amp used to provide the gain in the feedback circuit is slow, the transistor used to control the current is slow, and the current feedback signal is slower still because of parasitic capacitances. Oscillations result when the combined sluggish response of the op-amp, transistor, and feedback is so slow that the feedback response contributes to amplifying the next oscillation instead of contributing to damping. This sluggishness of response is commonly called xe2x80x9cphase lag,xe2x80x9d the condition of oscillating occurring when the phase lag is greater than 180 degrees and when the circuit is still amplifying (gain greater than 1). When the lag is greater than 180 degrees, the feedback starts to return back to a same part of a cycle, causing oscillation. When the lag is 360 degrees, the feedback comes completely back to the same part of the oscillatory cycle. In this manner, the switching of diode voltages can cause LED cable oscillations.
Conventional methods for addressing oximeter diode driver performance have included, for example, setting respective references for the drive voltage at a first voltage level and a second voltage level, and then supplying current to emitter circuits only when the drive voltage is at a first voltage level. Such a method sets the selected voltage reference to a value that determines the magnitude of the desired drive current. However, such conventional systems do not correct a phase lag of a diode drive circuit, but merely compensate for a slow voltage rise time by adjusting a corresponding timing for supplying a drive current.
As noted above, the switching of voltages in an oximeter can cause LED cable oscillations. This problem is compounded by the need for lowering a power consumption and cost of an oximeter. The conventional diode drive circuit discussed above is inefficient and expensive because it requires multiple reference amplifiers and prolonged stabilization periods between switching. Such a drive circuit necessitates a changing of timings for driving the diode
Another conventional oximeter diode drive circuit attempts to compensate for lag by lowering the slew rate of the output voltage to the diode, and by using additional load capacitance. However, the voltage across the capacitor will bleed down, causing a power loss, and oximeter performance is reduced significantly by a decoupling of the drive current to the diode. In addition, adding the load capacitor does not reduce a generation of front end noise, does not stabilize a control of the current driving, and does not eliminate any noise from a drive circuit itself.
An additional conventional method uses a low gain in a feedback loop of a driver circuit. However, this greatly reduces a performance of a driver circuit and also does not actually reduce noise, but merely reduces a dynamic range for diode drive current control and reduces an amplitude of a resultant ringing.
What is needed is a method and apparatus for stabilizing the driving of a current through a diode of an oximeter, where a low cost and a low power consumption are achieved along with tight control of the current through the diode. In addition, a clean diode current source with expanded dynamic range is needed for improving resolution and signal-to-noise ratio in oximetry systems. The effects of front-end, diode current noise are compounded by a use, for example, of laser diodes, which have very non-linear characteristics compared with conventional LEDs. This non-linearity of a laser diode means that a high-bandwidth laser diode cannot withstand an overcurrent state due to oscillations, even for a short period of time. As a result, conventional diode drive circuits may cause a complete breakdown of a laser diode. An example of a use of laser diodes in pulse oximetry is disclosed in U.S. Pat. No. 6,253,097 to Aronow, et al., which is incorporated by reference in its entirety.
It is an object of the present invention to prevent oscillations caused by sluggish performance of a diode driver circuit.
It is another object of the present invention to correct phase lag of a diode driver circuit without requiring that a timing of switching of the diode be changed.
It is a further object of the present invention to improve over conventional diode driver circuits by allowing for faster switching and more accurate control of multiple diodes.
It is an additional object of the present invention to stabilize a feedback type current source with a low-cost ferrite bead.
It is a still further object of the present invention to stabilize a current source that includes a current-sensing feedback arrangement.
It is yet another object of the present invention to identify a noise source in a diode current sourcing circuit and then reduce that noise, with or without affecting a current passing through the diode.
It is another object of the present invention to maintain a tight control of diode current in a diode driver circuit of an oximeter.
The present invention provides an apparatus including an amplifier having feedback, a resistor that senses a current being input to the amplifier, and an inductor that adds phase lead to the current.
A method for driving a current through a diode of an oximeter according to the present invention includes sensing a current of a signal being input to a feedback type amplifier, adding phase lead to the signal being input to the feedback type amplifier, and driving a diode with at least part of the signal having added phase lead.
A method for driving a current through a diode of an oximeter according to the present invention includes driving a current through the diode by connecting the current to the diode, controlling the connecting using a feedback type amplifier, the feedback type amplifier having a current source that uses a current-limiting resistor, and adding phase lead to a current passing through the current-limiting resistor.
An oximeter diode-driving device according to the present invention includes a diode, a transistor operative to controllably connect current to the diode, a current sensing resistor that senses at least part of the current, a feedback amplifier operative to control the connecting of current by the transistor according to the current sensed by the current sensing resistor, and an inductor in series with the current sensing resistor.
As a result of implementing the present invention, oscillations due to diode cable probe reactances are reduced or eliminated without degrading current control. In addition, dynamic range is increased, and power consumption and cost are reduced.
These and other objects, features, and advantages of the present invention will become more apparent when considered in connection with a detailed description of preferred embodiments, which are illustrated in the accompanying drawing figures.
This summary does not limit the invention, which is instead defined by the appended claims.


For use in medical trays the filtering flat material (2) has to be such that no micro-organisms can penetrate through it. In order to arrange such a filter (1) for achieving closure of a tray""s partial surface including through openings which ensures sterility, a closed sealing line, which surrounds the through openings, is formed in the area of each flat partial surface having through openings, along which two tray parts to be assembled and including co-operating clamping surfaces enable clamping the seal (3) of the filter (1). By the elasticity of the seal (3) sufficiently good closure is ensured even by small clamping pressure and even with not precisely plane clamping surfaces. The bond of the seal (3) to the filtering flat material (2) has the additional advantage that the filter (1) can also be arranged at a lower surface by pressing its seal (3) into a corresponding groove and does not loosen due to gravity.

The invention relates to a tray.
When using medical implements which possibly might contact blood in an investigation or operation of a live body, these implements have to be sterile up to their employment. After use they are cleaned and/or desinfected, sterilised and stored. The resulting manipulation labour should be as small as possible. From DE 196 27 044 A1, a tray is known which can be inserted both into a washing device as a wash basket and into a sterilisation device as a sterilising tray. Before sterilising, the tray is closed at top and bottom by an inserted filter. To this end, pieces of a steam permeable, germs retaining filter paper are inserted into slots, and are optionally held by a clamping facility. When transporting the implements to washing, thermal desinfection and to sterilisation after use, the same need no longer to be taken by hand, but can remain within the tray. Now, it has turned out that insertion of the filters is awkward. In order to protect the filter against mechanical influences, a covering element has to be put on in some cases. Moreover, in spite of the filter papers inserted, sterile storage of implements within the tray is not ensured, because complete closure around the filter to the inner space of the tray cannot safely be realised.
Trays available on the market are known which comprise a perforated area in a central bottom region. Outside the perforated area, threaded bolts project from the bottom of the tray into its receiving region at the corner points of a rectangle. Filter paper is inserted between the threaded bolts and covers the perforated area. Subsequently, a perforated metal sheet is laid upon the filter paper aligned with the perforation of the perforated area. The threaded bolts penetrate bores of the perforated metal sheet. Now, the perforated metal sheet can be pressed against the tray bottom by nuts on the threaded bolts. By tightly clamping the filter paper, any exchange of a gas or steam between the inner space of the tray and the environment can only be effected through the filter paper. In this way, sterile storing within the tray is made possible. It has turned out, however, that the expenditure for material, production and manipulation is very high due to the additionally inserted perforated metal sheet and the awkward manner of fastening. In addition, this approach is limited to insertion of the filter paper from above onto a perforated area which is on bottom at least during insertion. This approach is not suited for a wash basket in accordance with DE 196 27 044 A1, because the implements had to be removed after washing and before the filter paper could be inserted from above.
The object of the invention consists in providing a tray at which a flat perforated area can be closed by flat filter material with small expenditure in such a way that any exchange of gas and steam between the inner space of the tray and the environment can only be effected through the filter paper. Sterile storing within the tray should be ensured over an extend period of time.
Within the scope of the present invention, it has been recognised that a seal has to be connected to the flexible, flat filter material. This seal extends preferably in a marginal area of the flexible, flat filter material along a closed line. The filter material has to be such that no micro-organisms can penetrate it. In order to arrange such a filter for achieving a closure, which ensures sterility, on a partial surface of the tray having through holes, it is sufficient that a closed sealing line is formed around the through openings and to enable clamping the seal of the filter along the parts of the tray to be interconnected by means of co-operating clamping surfaces. By the elasticity of the seal a sufficiently good closure is ensured even by small clamping pressure and even with not precisely plane clamping surfaces. Any costly screwing down a perforated plate can be omitted.
The connection of the seal and the flat filter material has the additional advantage that the filter can also be arranged at the lower side by pressing its seal into a groove and does not loosen due to gravity from the lower side. After clamping the seal between the clamping surfaces, the seal prevents any micro-organisms from entering the inner space of the tray around the filter. Due to the possibility of fastening the filter in a groove, a filter can be arranged, for example, at the inner side facing the bottom of a cover member which has a perforated area. The cover together with the filter is then put, for example, onto the closed periphery of a wash basket so that the upper front surface of the periphery presses against the seal of the filter. In this way, the inner space of the wash basket is accessible from above only through the filter. The filter is protected against any damages by the cover surface above. Analogously to the cover, a bottom having a filter inserted can be fastened to the lower front surface of the wash basket""s periphery in such a way that the filter seal is clamped between bottom and periphery. In addition, cover and bottom may be formed as identical closing members, thus, being exchangeable. In order not to obstruct the desired penetration of steam through the inserted filter, the arrangement of holes of the closing members and the wash basket are formed congruently one above another. For clamping the closing members under pressure, a clamping device is provided which acts by force optionally between cover and bottom, preferably, however, between one respective closing member and the periphery.
The filter according to the invention having a seal fastened to the flexible, flat filter material can also be employed advantageously in a tray which is used exclusively for sterilisation and, optionally, for subsequent sterile storing. A simple construction of such a sterilisation tray comprises a bottom and/or cover member having a perforated area, a peripheral region of a bottom and/or cover member engaging it positively. By putting a filter according to the invention onto the perforated area in such a way that its seal is pressed by a closed periphery of the one part against a closed partial surface extending around the perforated area of the other part, sterile closure can be ensured.
For producing the filter with a seal a linear closed seal is applied by a foaming appliance onto the flat material held by a device, which is polymerised after application, thereby providing a bond with the flat material. It would be also possible, having some more expenditure, to adhere a sealing ring onto the flat material. Optionally, the flat material cut to the desired size before applying the seal. Preferably, however, the seal is applied to a ribbon of flat material. Severing the individual filters is preferably done later. After applying the seal, preferably at least one temperature treatment is carried out in correspondence with the sealing material applied. When using a silicone foam, a first temperature treatment is carried out, for example, during at least 3, particularly 5, minutes at at least 50xc2x0 C., particularly, however, at substantially 60xc2x0 C., and optionally a second temperature treatment during at least 10, particularly 20-30, minutes at at least 120xc2x0 C., particularly, however, at substantially 140xc2x0 C. For medical applications preferably silicone foams are used, in particular those which are suitable for food and/or admitted by the Health Department.
Foamed silicone seals have a temperature, moisture and pressure resistance needed for sterilisation. This means that they reassume sufficiently quickly the initial shape after sterilisation. They maintain the desired elasticity and shape even after passing sterilisation procedures several times. Even in cases where they do not provide a tight closure because of some deformation due to temperature or pressure during sterilisation, a tight closure is ensured at least during subsequent storage. Foamed seals have a great deformation capacity and are, therefore, especially suitable for sealing clamping surfaces of high tolerance with respect to plane joining together.