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BACKGROUND OF THE INVENTION
This invention relates to a process for alkalizing cocoa in the aqueous phase to improve its colour, taste and dispersibility and to enable a wide range of colours to be obtained therefrom.
FR-PS No. 2 445 698 already describes a process for solubilizing (or alkalizing) cocoa. To explain the process according to this Patent in more detail, the various phases involved in the production of soluble cocoa need to be specified: after cleaning and sorting, the raw nibs are crushed and degermed, the product obtained representing the meal.
This meal is then subjected to pregrinding, as a result of which the cells are broken and release the cocoa butter, the product obtained representing the ground meal or cocoa liquor. This ground meal is then converted into pure paste by fine grinding. Finally, the cocoa butter is separated from this pure paste and it is from the cakes obtained that the cocoa powder is prepared. The cocoa may be roasted in the form of the nibs, the meal, the ground meal or the pure paste. The process according to the above-mentioned French Patent may be applied both to the green or roasted ground meal and to the pure paste or the cakes. In this process, steam and a concentrated solution of an alkali carbonate are continuously injected under pressure into the cocoa mass in a tube, the carbonate is left to react with the cocoa mass for 30 to 80 seconds at a temperature of at least 120° C., the mixture is subjected to sudden expansion and then dried with stirring. Apart from the disadvantage of the relatively high alkalizing temperature, it is not possible by this process to produce cocoa powders in a wide range of colours, particularly in shades of red or red-brown. Now, cocoas produced in colours such as these are very much in demand at the present time because they have a strong colouring power, thus eliminating the need to use food colorants which are prohibited in many countries. Obviously, these cocoas also have other advantages which will be explained hereinafter.
EP-PS No. 66 304 relates to a cocoa powder having this red or red-brown colour. The powder in question is obtained by alkalizing cocoa powder with approximately 75% water for 4 to 24 hours at a temperature of from 65° to 90° C., the water being replaced as its evaporates. The major disadvantage of this process is that it involves a long alkalizing time and a high consumption of energy during the final evaporation in view of the quantities of water added during the alkalizing process.
SUMMARY OF THE INVENTION
The process according to the invention, in a first step, comprises alkalization without evaporation of water under a pressure of from above 1 atmosphere to 3 atmospheres and, in a second step, evaporation of the water. The advantage of effecting alkalization initially without evaporation of water is that it is possible to work under perfectly controlled conditions and to retain the water for a desired period: the same quantity of water thus being available throughout the entire alkalization reaction, which promotes the treatment of the polyphenols largely responsible for the red colour, the bitterness, the chocolate taste and the pigment solubility of the cocoa. The cocoa and the alkalizing agent dissolved in water are thus introduced into a closed vessel and heated, care being taken at the beginning of the reaction to allow the carbon dioxide formed during the reaction to escape, and the reaction is continued with vigorous stirring in the closed vessel under a pressure of from above 1 atmosphere to 3 atmospheres. In order to create this excess pressure, air, compressed air or an oxygen-containing gas mixture is introduced into the reaction mixture throughout or during part of the alkalization time. Working under excess pressure has a favourable effect in assisting the cocoa to develop a more intense red coloration.
Since alkalization is carried out under controlled conditions, the aroma quality and colour of the cocoa may be selected by varying any of the parameters of the alkalization reaction, namely the alkali content, the water content, the alkalization and evaporation temperature and the alkalization time.
The process according to the invention gives a cocoa which develops a good aroma and of which the pH tends towards neutral, the pigments of the cocoa powder obtained being characterized by good solubility which has an economic advantage in regard to the colouring power, enabling a more intense coloration to be obtained for a smaller cocoa content than with conventional cocoa powders.
DETAILED DESCRIPTION OF THE INVENTION
The process according to the invention may be applied both to the meal and to the liquor in the roasted or non-roasted state. Alkalization is carried out with sodium, potassium, ammonium or magnesium hydroxide or carbonate, preferably with potassium carbonate. The alkali content used is from 1 to 3% by weight, based on the weight of the cocoa.
A content above 3% does nothing in regard to the red coloration and, on the other hand, increases the pH. A content below 1% does not give a sufficiently alkaline medium. The alkali is preferably used in a quantity of from 2 to 2.5% by weight, based on the weight of the cocoa.
The alkali is dissolved in water before its incorporation in the cocoa mass. According to the invention, the water content is from 10 to 50% by weight, based on the weight of the cocoa, in the case of the liquor and from 10 to 100% in the case of the meal.
It is inherent in the nature of the starting material that more water is used for the treatment of meal because it absorbs water to 70% of its own weight. By contrast, less water is used for the treatment of liquor and a higher temperature is used for its evaporation. It is of course uneconomical to use too high a water content because this would increase the consumption of energy for evaporation. The preferred water content is from 10 to 25%, based on the weight of the cocoa, in the treatment of liquor and from 60 to 80% in the treatment of meal.
The alkalization temperature is below 110° C. This is because at a higher temperature, as in known processes, the cocoa is less dark and the red coloration absent. Alkalization is preferably carried out at a temperature of from 60° to 100° C.
Compared with the process according to EP 66 304, the process according to the invention enables the alkalization time to be considerably shortened. The alkalization time is from 30 minutes to 4 hours. A long alkalization time tends to reduce the pH, to intensify the coloration and to develop a good red colour of the cocoa.
In the process according to the invention, alkalization is initially carried out--as mentioned above--in a closed vessel, after which the vessel is opened and the water is evaporated. Evaporation of the water takes place as quickly as possible at a temperature of from 70° to 120° C. either in the same vessel as used for alkalization or in another vessel. A higher temperature may optionally be briefly applied towards the end of evaporation. In that case, cocoa having a moisture content of 2% or less is obtained.
Despite the relatively large quantity of alkali used, the cocoa thus obtained is free from the alkaline taste characteristic of cocoas obtained by known processes. On completion of alkalization, the cocoa mass is conventionally treated to convert it into cakes and cocoa powder ready for marketing.
The cocoa powder thus obtained has a pH of from 6.8 to 8.5 which is interesting because it is known that an acidic cocoa has a weaker colouring power than a neutral or slightly alkaline cocoa. On the other hand, the aqueous extract of this powder has an optical density at 20° C. of from 0.6 to 1.3 (as measured on a 1% solution in a 1 cm cell at a wavelength of 490 nm). For comparison, the extract of an ordinary brown cocoa powder has an optical density, as measured under the same conditions, of from 0.2 to 0.5.
The process according to the invention enables cocoa to be produced in colours ranging from red to dark brown without a high energy consumption. In conventional industrial processes, alkalization is accompanied by the evaporation of water from the beginning of the treatment and it is for this reason that a higher temperature is generally applied. This results in continuous variation of the alkalization conditions, the treatment time being determined by the time necessary to evaporate the water. Another disadvantage of these known processes is that they cannot be adapted to meet the specific requirements of various qualities of cocoa and cocoa nibs.
The cocoa powder thus obtained may of course be used for numerous applications, i.e., for chocolate-flavoured beverages, in chocolate manufacture, in confectionary, in deep-frozen foods and other applications for which its advantages as explained above make it highly desirable.
The process according to the invention is illustrated by the following Examples.
EXAMPLES
Because the colour of the cocoa or cocoa powder is of considerable importance in accordance with the invention, it is necessary to define the parameters by which that colour may be measured. A Philips PYE UNICAM SP 8-100 spectrophotometer equipped with an attachment for measuring colour and connected to an HP 85 computer was used for this purpose. This spectrocolorimeter measures the spectrum of the light reflected by a sample placed in a cell. The intensity of the light is measured for each wavelength. This information enables the trichromatic values X,Y,Z to be obtained. All the colours may be calibrated as a function of the trichromatic values. To be represented in one plane, the trichromatic coordinates x,y,z have to be calculated from the trichromatic values. To represent the difference in colour between two samples, the values L,a,b have to be calculated: L represents the brightness, a the red component (a>0) and b the yellow component (b>0).
The value L varies from 0 (black) to 100 (white). The closer it comes to zero, the darker the cocoa. So far as the red is concerned, the higher the ratio a:b, the more red the colour of the cocoa.
EXAMPLE 1
250 g roasted cocoa liquor coming from a production line were preheated in a laboratory mixer. 5 g potassium carbonate dissolved in 50 g hot water were added to and mixed with the cocoa mass. The mixer was hermetically closed with a cover and the temperature adjusted to 100° C. A pressure was created inside the mixer by connection to compressed air. The pressure was adjusted to 2 km/cm 2 , these conditions being maintained for 3 hours. Thereafter, to dry the cocoa mass, an opening was formed in the cover of the mixer, enabling the water to evaporate. The temperature inside the reactor was increased to 120° C. and the mass was dried for 2 hours to a final moisture content of <2%.
The colour of the cocoa mass was darker than usual with a reddish tint. Nevertheless, the pH did not exceed 7.2.
COMPARISON EXAMPLE 1
A cocoa liquor was mixed with a potassium carbonate solution as described in Example 1. The mass was then treated as in the conventional industrial process, i.e., the mixer was heated to 130° C. and was not closed. The water thus evaporated in approximately 2 hours.
The colour of the mass was typically brown and the pH did not fall below 7.8.
The results of the colour measurements of the alkalized cocoa mass confirmed the visual observation. It is obvious that the same difference in colour is encountered in the cocoa powders prepared from these masses.
______________________________________ pH L a b a:b______________________________________Example 1 7.2 2.06 5.59 3.23 1.73Comparison Example 1 7.8 6.03 9.40 7.21 1.30______________________________________
The colour (L,a,b) of the cocoa mass was measured with a PYE UNICAM spectrophotometer by melting the cocoa mass in the cell.
EXAMPLE 2
3 kg green (=non-roasted) meal were granulated (diameter 2 mm) and then mixed with 3 kg water--in which 75 g K 2 CO 3 had been dissolved--in a kneader. The temperature was adjusted to 80° C. (double-jacket heating) and the kneader was closed with a cover. An excess pressure was created inside the kneader with compressed air. After an alkalization time of 2 hours, the meal was transferred to an air dryer, dried at a temperature of 80° C. (for approximately 1.5 to 2 hours) and then roasted for 20 minutes at 120° C.
A cocoa powder was produced by the usual operations (pressing, grinding, sieving and conditioning).
Results of tasting of the cocoa powder: very pleasant colour--fairly dark, distinct brown-red. Organoleptic quality: very well developed cocoa taste, highly appreciated aroma.
Results of colour measurement of the cocoa powder: L=25.83, a=15.18, b=10.95, a:b=1.38.
COMPARISON EXAMPLE 2
The procedure was as described in Example 2, except that no pressure was applied in the kneader. On the other hand, alkalization was continued for 6 hours.
Results of tasting of the cocoa powder: colour brown tending towards red, weaker, flat, less developed, unclean taste of cocoa.
Results of the colour measurement of the powder: L=30.53, a=13.46, b=11.74, a:b=1.15.
In these Examples, L,a and b were determined by placing the cocoa powder directly in the measuring cell.
Through these comparison tests, it was shown that an air pressure above atmospheric pressure during alkalization advantageously replaces a long alkalization time which is necessary for the good development of colour and taste at low temperature.
Among the commercial cocoa powders measured for colour by the same method, none was as dark (L>33) or as red (a:b<0.9).
EXAMPLE 3
The cocoa powder produced as described in Example 2 was used in confectionary to improve the colour of cake. The confectioner then carried out a comparison test with a cocoa powder typically used for production of cake. The result according to the confectioner was quite spectacular. The new cocoa had given a much more intense and warmer colour tending towards brown-red.
It was estimated that, by using the new powder, the normal cocoa dose of 4.3% (based on the weight of the cake) could be reduced to 2.9% for the same result. This represents a saving of approximately 30%.
EXAMPLE 4
(a) A red cocoa powder (1 g), such as described in Example 2, was dispersed in water (100 ml). After filtration (0.45 μm), a strongly coloured aqueous cocoa extract was obtained. The absorption of this extract was measured with a PYE UNICAM SP 8-100 spectrophotometer at a wavelength of 490 nm (absorption maximum). Result: O.D.=1.09 (1 cm cell)
The extract of an ordinary (brown) cocoa powder was prepared for comparison and measured for absorption: Result: O.D.=0.27 (1 cm cell)
The solubility in water of the pigments of a cocoa powder according to the invention shows a distinct improvement over ordinary powders. This is of considerable advantage in practice because large amounts of cocoa powder are used for the Produotion of cocoa-flavored beverages.
(b) The cocoa powders were dispersed in hot water (70° C.) After filtration, absorption was measured with the following results:
red cocoa (according to the invention): O.D.=1.44
brown cocoa (ordinary): O.D.=0.47
The solubility of the pigments is even higher at elevated temperature, which is an advantage for hot cocoa beverages. The consumer is attracted by a rich cocoa colour.
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For improving the taste and dispersibility of cocoa and for obtaining alkalized cocoa to which is imparted red coloration for obtaining a wide range of colors in shades of red and brown, cocoa meal or liquor and an alkalizing agent in aqueous phase are mixed and heated in an enclosed vessel under a pressure of from above 1 atmosphere to 3 atmospheres at a temperature below 110° C. without evaporation of water while introducing an oxygen-containing gas into the vessel during at least a part of the mixing and heating for maintaining the excess pressure. After the cocoa is alkalized, water is evaporated from it.
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This invention claims the benefit of priority to U.S. Provisional patent application Ser. No. 60/410,110 filed Sep. 12, 2002.
FIELD OF THE INVENTION
This invention relates to optical communication systems, and more particularly to all optical systems and methods of data regeneration after signal degradation occurs due to long distance transmission.
BACKGROUND AND PRIOR ART
To meet the growing capacity demand of fiber optic communication system, more channels and higher line-rates have to be considered in dense wavelength-division multiplexing (DWDM) systems. These systems suffer from many propagation impairments, such as amplified spontaneous-emission (ASE), four-wave mixing (FWM), cross phase modulation (XPM), and stimulated Raman scattering (SRS).
All these effects limit the transmission distance and optical regeneration is necessary to restore optical data signals. In an all-optical network, the need is even more acute as the optical signal may not only travel over variable distance but also go through unpredictable numbers of switching nodes.
In conventional opto-electronic repeater/regenerators, two complete WDM (wave-division multiplexing) terminal equipments in a back-to-back configuration are used. They are expensive since both O-E and E-O conversion are required, and will be finally bandwidth-limited. In the future high speed long-haul transmission systems or large-scale optical networks, all-optical regeneration, including 2 R (reshaping and reamplification) and 3 R ( 2 R plus retiming) are key technologies to overcome the electronic bottleneck.
Many approaches have been proposed for optical 3 R regeneration. The majority of them can be classified into the following categories: 1) cross-gain modulation (XGM) regenerators using semiconductor optical amplifiers (SOA) and/or distributed feedback (DFB) lasers; 2) interferometric regenerators using cross phase modulation (XPM) in SOAs or optical fiber; 3) cross-absorption modulation in electro-absorption modulators (EAM); 4) soliton-based regenerators using synchronous modulation; 5) noise suppression on bit 1 's using gain saturation in SOAs or fiber parametric amplifiers; and 6) regenerators based on spectral broadening due to self-phase modulation (SPM); 7) high-order parametric processes.
Regeneration schemes based on gain dynamics of SOAs are limited in speed by the carrier recovery time and in ER by weak gain saturation. As a result, it is unlikely XGM or gain saturation in SOAs will function at 40 Gb/s and above. Other schemes and their potential problems with these approaches are hereafter discussed to place the invention of this application in the proper context. The review is focused on nonlinear optical gating.
Interferometric Regenerators
Interferometric regenerators based on XPM in SOAs can be of the Mach-Zehnder (MZ), Michelson or delay interferometer types exploiting similar phase dynamics as used in the terahertz optical asymmetric demuliplexer (TOAD). A MZ regenerator uses two symmetric SOAs. The input data to be regenerated is split into two equal parts, one is delayed with respect to the other. The retimed clock pulses are also fed equally into the two MZ arms. Because of the relatively delay, the phase difference experienced by the clock pulses in the two arms is roughly a series of rectangular pulse of width τ and height π. The transfer function of the interferometer is sin[(Φ 1 −Φ 2 )/2]. The speed of operation of this regenerator is limited only by the rise time, not by the carrier recovery time. As a result, regenerators based on XPM in SOAs have been demonstrated to operate as high as 80 Gb/s (and XPM based wavelength conversion up to 160 Gb/s). The other advantage is that the sensitivity of such regenerators is among the highest of all the optical regenerators due to strong nonlinearities in SOAs. The disadvantages of this type of regenerator are as follows. Because data to be regenerated in general will have long-term average power fluctuations and short-term pattern-dependent effects, the data need to be pre-processed so that the peak power of each bit is the same. Pre-processing in general only optimize operation of bit 1 's of the original data to be regenerated. Therefore only the noise of bit 1 's (non-inverting regenerator) or bit 0 's (inverting regenerator) will be reduced by the regenerator depending on the initial phase delay of the interferometer.
Interferometric regenerators based on XPM in fibers are in general realized in the form of a nonlinear optical loop mirror (NOLM). It exploits the phase difference between the co-propagating and counter-propagating path. The NOLM has ultra high speed potential. It is not very practical because of the interferometric stability with long (˜km) length of the fiber loop, and as in the case of SOA based XPM regenerators, it requires preprocessing.
Cross-Absorption Regenerators
All-optical regenerator based on cross-absorption modulation in EAMs exploits saturation effects in EAMs. This regenerator consists of an EAM with two inputs: the data to be regenerated and a probe laser. At bit 1 's, the input data saturates the absorption of the EAM, leaving it transparent to the probe laser. At bit 0 's the EAM is still absorptive to the probe laser. In order to obtain (thresholding effects) improved ER, the EAM should be biased at a very lossy state and strong injection power is required. The average power required for the data signal is on the order of +17 to +19 dBm. The speed is limited by the carrier recombination speed, which is in general faster than the carrier recovery speed of lasers. Speeds up to 40 Gb/s have been demonstrated. The disadvantages of cross-absorption regenerators are: 1) it has a very low sensitivity (high input power) and 2) the speed is limited to about 40 Gb/s.
Soliton-Based Regenerators
Soliton-based regenerator exploits the robustness of soliton pulses under synchronous modulation. Synchronous modulation has been used to transmit solitons over unlimited distance. Soliton-based regenerator first converts the regular dispersion-managed RZ pulses to soliton pulses, which is optically filtered and then synchronously modulated by a recovered clock signal (synchronous modulation). The soliton pulses (bit 1 's) that emerge from synchronous modulation is robust while noise pulses (bit 0 's) will disperse. In addition, synchronous modulation reduces jitter in soliton pulses as the centers of the pulses attract towards transmission peaks at exactly the clock rate. This process can be repeated, each time resulting in a better ER and smaller jitter until reaching an ER and a jitter floor. Although synchronous modulation of multiple channels can be envisioned, RZ-to-soliton and soliton-to-RZ conversions have to be performed in separate channels since the conversion conditions for each channel are different. In addition synchronous modulation requires that each channel have the same clock rate. This is not generally satisfied because different WDM channels often come from different sources with independent clocks. Despite the attention this scheme has received, this approach is not cost effective with OEO regeneration when the cost of preprocessing (RZ to soliton) and post processing (soliton to RZ), which needs to be performed on a per channel basis, is factored in.
Regeneration Using Gain Saturation in Fiber Parametric Amplifiers
This involves regeneration using gain saturation in fiber parametric amplifier (FPA). The pump for the parametric amplifier is a CW laser (for 2 R) or retimed clock pulse train (for 3 R) and the data to be regenerated is used as the probe. Before input into the FPA, the probe is amplified so that bit 1 's will saturate the pump. As a result only bit 1 's can be reshaped. It should be noted that this gain saturation is due to pump depletion when the pump power is transferred to the probe. Compared to SOA's with saturated gain, this scheme can operate at high speeds. Inherently, this scheme is not very competitive because reshaping of the bit 1 's comes at the expenses of reduced ER. As a result, negative power penalty cannot be achieved. Practically, when a signal needs to be regenerated, its ER is already low and the reshaped signal with a further reduction in ER would not be able to transmit any further in fiber.
Regeneration Using Self-Phase Modulation
In regeneration using self-phase modulation, the input pulses to be regenerated have a spectral width on the order of Δω 0 ˜1/τ, where τ is the pulse width. Due to the effect of SPM, the spectral bandwidth of the pulses broadens to Δω SPM =Δω 0 (2π/λ)n 2 I p L, where I p is the pulse intensity (which can fluctuate), n 2 is the nonlinear refractive, λ is the wavelength and L is the length of the nonlinear fiber. After SPM, the pulses pass through an optical filter whose center frequency, ω f , is shifted with respect to the input signal carrier frequency, ω 0 as ω f =ω 0 +Δω shift . If the spectral broadening of the pulse is small enough so that ω SPM /2<Δω shift , the pulse is rejected by the filter. If the pulse intensity is high enough so that ω SPM /2≧Δω shift , a part of the SPM-broadened spectrum passes through the filter. This regeneration scheme on surface is quite attractive. It uses only passive component, can lead to ER improvement. However, there is a major problem in terms of retiming with this scheme. First, it does not allow a retiming mechanism. Second, the intensity fluctuations (noise and pattern effects) in the input data can lead to significant jitter up to ±10% τ. To solve the retiming issue, this scheme has been combined with synchronous modulation.
High-Order Parametric Processes
Recently optical regeneration using high-order parametric processes has been proposed. It relies on multiple nonlinear optical interactions that involve multiple pumps and multiple idlers. As such, it is complicated, requires complicated filtering, and has limited dynamic range.
Thus, the need exists for solutions to the above problems of the prior art.
SUMMARY OF THE INVENTION
A primary objective of the present invention is to provide a method and apparatus for all-optical 2 R (reamplification and reshaping) regeneration.
A secondary objective of the present invention is to provide a method and apparatus for all-optical 3 R ( 2 R plus retiming) regeneration.
A preferred embodiment of the invention is the 2 R regeneration apparatus that comprises: a high power Erbium-doped fiber amplifier (EDFA) which boosts the input data signal as the pump of the exponential amplifier; a continuous wave(CW) probe; an exponential amplifier which could be a piece of fiber with parametric amplification; and a limiting amplifier, which could be a SOA.
Another preferred embodiment of the invention is the 2 R regeneration apparatus that comprises: a high power Erbium-doped fiber amplifier (EDFA) which boosts the input data signal as the pump of the exponential amplifier; a continuous wave(CW) probe; a fiber parametric amplifier in which the exponential gain at low pump levels is followed by flattened gain at high power levels due to self-phase modulation induced spectral broadening.
The preferred embodiments of the invention for 3 R regeneration are different from the aforementioned 2 R regeneration apparatuses in that the CW probe of the former is replaced by pulsed light source with its timing provided by clock recovery.
The applications of the present invention include all-optical regeneration in long-haul fiber communication systems or optical networks, especially when the signal travels an unpredicted distance and become distortion. It also could be used as a front-end of the optical receiver to improve the signal extinction ratio to minimize the error rate.
Further objects and advantages of this invention will be apparent from the following detailed description of a presently preferred embodiment which is illustrated schematically in the accompanying drawings.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is a first preferred embodiment layout for a format insensitive 2 R regeneration.
FIG. 2 is a first preferred embodiment layout for a format insensitive 3 R regeneration.
FIG. 3 shows the parametric conversion efficiency as a function of the peak pump power shows the exponential relationship with moderate pump condition.
FIG. 4 shows the output vs. input power relationship of SOA at saturation state.
FIG. 5 a shows eye diagrams at approximately 5 Gb/s for a extinction ratio seriously degraded signal. The horizontal scale is approximately 50 ps/div and the vertical scale is 200 mV/div. The extinction ratios are approximately 4.5 dB, approximately 18 dB, and approximately 15.4 dB respectively.
FIG. 5 b shows an eye diagram at approximately 5 Gb/s for a idler signal after parametric amplification by a DSF.
FIG. 5 c shows an eye diagram at approximately 5 Gb/s for final regenerated signal.
FIG. 6 shows simultaneous exponential amplification and limiting amplification with a single piece of fiber as a parametric amplifier.
FIGS. 7 a , 7 b , 7 c , and 7 d shows 2 R regeneration for approximately 10 Gb/s NRZ data.
FIGS. 8 a , 8 b , 8 c and 8 d shows 2 R regeneration for approximately 10 Gb/s RZ data.
FIG. 9 shows a graph of sensitivity improved by using highly nonlinear crystal fiber.
FIG. 10 shows the experimental setup for 2 R regeneration.
FIG. 11 shows the transfer function of the parametric fiber amplifier with regular dispersion shifted fiber (dashed line) and the highly nonlinear fiber (solid line).
FIG. 12 a shows the data pattern of the input data.
FIG. 12 b shows the eye diagram of the input data.
FIG. 12 c shows the data pattern of the regenerated data of the preceding figures.
FIG. 12 d shows the eye diagram of the regenerated data.
FIG. 13 shows the BER measurements of the approximately 10 Gb/s input signal and regenerated data respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Before explaining the disclosed embodiments of the present invention in detail it is to be understood that the invention is not limited in its application to the details of the particular arrangements shown since the invention is capable of other embodiments. In addition, the terminology used herein is for the purpose of description and not of limitation.
With respect to the terminology, a short review is presented hereafter for a better understanding of the preferred embodiments. When used in the context of 3 R, the reshaping comprises two sub-functions: enhancement of the extinction ratio and noise reduction for bit 0 's as well as bit 1 's, which are realized by exponential amplification followed by limiting amplification. This invention lists 3 different combinations for the exponential amplification and the limiting amplification as follows: (a) a piece of fiber (dispersion shifted fiber or photonic crystal fiber) with parametric amplification as an exponential amplifier, where the bit 0 's of the input signal are located in the exponential amplification region; a semiconductor optical amplifier (SOA) operating in gain saturation state as a Limiting amplifier. (b) One piece of fiber as an exponential amplifier and another piece of fiber with different parameters as a limiting amplifier, where the bit 0 's are located in the exponential amplification region of the first fiber segment and the bit 1 's are located in the gain saturation region of the second fiber segment. (c) One piece of fiber as both an exponential amplifier and a limiting amplifier, where the bit 0 's and bit 1 's of the input signal are located in the exponential amplification region and gain saturation region respectively.
The 2 R regeneration scheme includes a high power EDFA, which boosts the input data signal as the pump of the exponential amplifier, a continuous wave (CW) probe, an exponential amplifier, which is a piece of fiber with parametric amplification in present invention, and a limiting amplifier, which could be a semiconductor optical amplifier (SOA) or a piece of fiber with parametric amplification operating in the saturation state, and the like. An advantage of using fiber with parametric amplification over SOA is its speed is significantly improved, but the parameters of the fiber should be carefully designed.
The only difference in the 3 R regeneration scheme is the CW probe is replaced with a clock recovery module, the input of which could be incoming signal or regenerated signal. The latter choice will be more favorable since the clock component will be stronger and clock recovery module will work better.
The applications of the present invention include all-optical regeneration in the long-haul fiber communication system or optical network, especially when the signal travels an unpredicted distance and become distortion. It also could be used as a front-end of the optical receiver to improve the signal extinction ratio to minimize the error rate.
The origin of fiber parametric processes lies in the nonlinear polarization induced by the applied optical field through nonlinear susceptibilities. When an intense pump wave is input to a fiber together with a signal wave, the signal is amplified, and at the same time a new signal called idler wave is generated, provided the phase matching condition is satisfied. Under the small signal condition (pump is not depleted), the parametric conversion efficiency (the idler power divided by input signal power) increases exponentially with the pump power as indicated by equation (1).
G C ≅ 1 4 exp ( 2 γ P 0 L ) ( 1 )
where γ is the nonlinear coefficient, P 0 is the pump power, and L is the length of the nonlinear fiber. For standard dispersion shifted fiber, a nonlinear coefficient of γ=2.7/km/W and an effective area of A eff =57 μm 2 .
The principle of the two-stage 2 R regeneration scheme is shown in FIG. 1 , where a first-stage exponential amplifier (such as an optical fiber parametric amplifier) precedes a second-stage limiting amplifier (such as an SOA.). The input signal to be regenerated is used as the pump of the exponential amplifier, whose gain increases exponentially with the pump power such as the case of optical fiber parametric amplifier. Therefore, bit 1 's will provide more gain to the CW probe than bit 0 's, thus increasing the extinction ratio of the output signal from the parametric amplifier. However, because of the exponential gain characteristics of the amplifier, the noise on bit 1 's in the pump (i.e., the data to be regenerated) will be transferred to the output. The second-stage amplifier such as an SOA provides gain-saturation to provide noise reduction on bit 1 's. In conclusion, the exponential amplifier provides extinction ratio enhancement while the saturation amplifier provide noise reduction on bit 1 's.
The principle of the two-stage 3 R regeneration scheme shown in FIG. 2 is similar to FIG. 1 except the CW probe is replaced by a retimed pulsed probed,
The experimentally measured parametric conversion efficiency vs. peak pump power is shown in FIG. 3 , where the gain media is an approximately 2 km long dispersion shifted fiber with zero-dispersion wavelength of approximately 1555 nm. The pump wavelength and the probe wavelength are approximately 1556 nm and approximately 1564 nm respectively. For example, if the pump signal has an extinction ratio of approximately 4 dB (approximately 26 dBm for low level and approximately 30 dBm for high level), the idle signal would have an extinction ratio of approximately 25 dB. On the other hand, this exponentially increasing conversion efficiency can also amplify the amplitude fluctuation at bit 1 . It is therefore necessary to deploy a limiting amplifier to suppress these amplitude fluctuations. A semiconductor optical amplifier (SOA) can act as a limiting amplifier if the input power is high enough to saturate its gain.
FIG. 4 shows the output power as a function of the input power, where the injection current of SOA is approximately 145 mA. It clearly indicates that the SOA falls into deep saturation at high input powers. When the input power is > approximately −4 dBm, the output power fluctuation is less than approximately 0.5 dB even if the input power fluctuates in a range of approximately 7 dB. The amplitude fluctuation at bit 1 is therefore suppressed.
FIGS. 5 a and 5 b show the approximately 5 Gb/s eye-diagrams before and after parametric amplification, where the signal wavelength was approximately 1564 nm and the pump peak power was approximately 1.4 W, respectively. The amplitude noise at bit 0 's was suppressed due to the threshold characteristics of parametric amplification. The extinction ratio improved significantly from approximately 4.5 dB to approximately 18 dB. However, parametric amplification could not suppress the amplitude noise at bit 1 's. In fact it amplified the amplitude noise at bit 1 's due to its exponential gain response to the pump power.
By employing an SOA operating in saturation state, the amplitude noise at bit 1 's could be reduced. The eye diagram of the regenerated data shown in FIG. 3 c indicates that an extinction ratio of approximately 15.4 dB was achieved when the average input power was approximately −15 dBm. The extinction ratio degraded by approximately 2.6 dB relative to the signal directly after parametric amplification since SOA 2 “exaggerated” the noise level of bit 0 's. The overall improvement of extinction ratio of the regenerated data was approximately 11 dB (over the degraded incoming data).
The exponential amplification and limiting amplification are also possibly realized by just one piece of fiber. The idler power vs. pump peak power relationship is shown in FIG. 6 . To demonstrate the format transparency, RZ and NRZ data signals are used as the pump respectively. The emergence of gain flattened (limiting gain) region is due to self-phase modulation induced spectral broadening which cause the pump power to be transferred to its neighboring frequencies rather than to the idler. If the bit 0 's of the pump signal are located in the exponential region while the bit 1 's are located at the saturation region, the noises of both bit 1 's and bit 0 's will be reduced and the extinction ratio will be improved at the same time. FIGS. 7 a , 7 b , 7 c and 7 d and FIGS. 8 a , 8 b , 8 c and 8 d simulates the signal regeneration for NRZ and RZ format respectively.
The main drawback of using dispersion shifted fiber as the parametric media is very high operating power requirement. However, this could be overcome by using highly nonlinear fiber by, for example, increasing Ge concentration in fiber core or creating photonic crystal fibers, both of which are currently intensively studied.
FIG. 9 shows the output idler power vs. pump peak power relationship by decreasing the effective core area from 55 μm 2 of the regular dispersion shifted fiber to approximately 10 μm 2 . It could be noted that the pump threshold is decreased about approximately 10 dB if compared to FIG. 6 .
To more fully understand the 2 R embodiment of the invention, reference should be made to FIG. 10 which illustrates the various components of the experimental setup for 2 R regeneration including: the mode-locked fiber laser (MFL) 92 ; polarization controller (PC) 94 : MZI: Mach-Zender LiNbO 3 modulator (MZI) 96 :, semiconductor optical amplifier (SOA) 98 ; BPF: bandpass filter (BPF) 100 ; Er 3+ doped fiber amplifier (EDFA) 102 ; and, the highly nonlinear fiber (HNLF) 104 .
In this experimental set up an approximately 9.953 GHz pulse train with an approximately 6 ps pulsewidth was generated from the mode-locked fiber laser (MFL) 92 . It was then encoded with an approximately 9.953 Gb/s pseudo-random bit-stream (PRBS) 93 of pattern length up to approximately 2 31 −1 through an external modulator. The semiconductor optical amplifier (SOA) 98 with a bias current of approximately 145 mA operating in saturation was used to introduce noises on bit 0 's and 1 's as well as pattern effect to the data signal to be regenerated. The optical bandpass filter 100 right after the SOA 98 was used to block the strong broadband ASE noise. The center wavelength of the data signal before and after the SOA 98 were approximately 1556 nm and approximately 1556.5 nm (due to the red shift of the saturated amplification). The data pulse train was amplified by an EDFA 102 and then launched into a 6 km long highly nonlinear fiber (HNLF) 104 as the pump of the fiber parametric amplification. The HNLF has a very small dispersion slope (approximately 0.017 ps/nm 2 /km) around its zero-dispersion-wavelength approximately 1552 nm. A CW laser 106 at approximately 1561.5 nm with the power level of approximately 8 dBm, which acts as the probe signal was coupled into the HNLF 104 through the 10% input port of a 90:10 coupler 108 with a power meter 109 attached thereto. The polarization state of the CW signal was adjusted by a polarization controller 110 to obtain the highest parametric gain. To prevent the strong pump signal from damaging the connectors and detectors, an optical isolator 112 and a fiber Bragg grating 114 , which was tuned to reflect the pump wavelength, were inserted right after the HNLF 104 to block the pump signal. An optical bandpass filter 114 with a 3-dB bandwidth of approximately 1 nm was used to select the idler component at approximately 1551.5 nm. The regenerated data 116 was analyzed by a digital sampling oscilloscope and an error detector(not shown).
Experimental Results
FIG. 11 shows the experimentally measured transfer function of the FPA using a HNLF in terms of the idler gain vs. the peak pump (the data signal to be regenerated) power. As a comparison, the transfer function of the FPA using a regular dispersion-shifted fiber (DSF) is shown in the same figure. The idler obtains exponential amplification at lower pump (the bit 0 's) and flattened gain at a higher pump (the bit 1 's) as result of pump energy transferring to other frequency components via self-phase modulation induced spectral broadening and supercontinuum generation. Since the nonlinear coefficient γ has been enhanced from approximately 2.7 W −1 km −1 to approximately 9.75 W −1 km −1 for the HNLF, the power required for flattened gain is greatly decreased from approximately 32.5 dBm to approximately 23.5 dBm. In addition, due to the small dispersion slope, the FPA gain-flattened range (within approximately 0.5 dB fluctuation for example) is also increased from approximately 0.6 dB to approximately 1 dB.
At the output of the SOA, the approximately 10 Gb/s PRBS data to be regenerated has reduced extinction ratio due to saturated amplification of the SOA. The ASE noise of the SOA adds noise at both bit 0 's and bit 1 's. Due to the finite gain recovery time of the SOA, bit 1 's also exhibit serious pattern effects.
FIGS. 12 a and 12 b show the data to be regenerated into the FPA and the corresponding eye diagram in amplitude vs. time. It should be pointed, although the extinction ratio is moderate (approximately 9 dB measured from DCA oscilloscope), the eye opening is quite small due to the noises on both bit 0 's and 1 's. In addition, pattern effect on bit 1 's is apparent from the “double eye” in the eye diagram. The regenerated data and the corresponding eye diagram are shown in FIGS. 12 c and 12 d respectively. One could notice that after the regeneration, both the noises of bit 0 's and bit 1 's have been reduced. As a result, the eye diagram was widely opened and the amplitude of the pulses (bit 1 's) became uniform. The corresponding extinction ratio is approximately 14 dB, which is already close to the highest extinction ratio measurable using the oscilloscope.
To ensure end-to-end system performance, a measurement of the sensitivity of the original data and the regenerated data was made and presented herein. The regeneration scheme indeed provides negative power penalty. FIG. 13 shows that at a BER of approximately 10 −9 , the receiver sensitivity of the regenerated data has been improved to approximately −19 dBm compared to approximately −14 dBm of the original degraded signal. Thus the regenerated data has an approximately 5 dB negative power penalty. This represents one of the best negative power penalties reported so far in literature.
Thus, a 2 R regeneration using a fiber parametric amplifier has been successfully demonstrated. An extinction ratio enhancement of approximately 5 dB has been obtained. Negative power penalty as much as approximately 5 dB indicates its attractive end-to-end transmission performance.
The experimental results demonstrated above uses input signal with extinction ratio degradation but no jitter degradation. For signals with jitter degradation, a 3 R regenerator will be used where the excess jitter is removed by the clock recovery process. In this case negative power penalty of the 3 R regeneration process will result from not only reshaping as in the 2 R case but also retiming.
Further improvement of the presentation can be made by use other material systems with high effective third-order nonlinear coefficients rather than optical fiber for parametric amplification. These materials can include bulk nonlinear optical crystals or semiconductors. By increasing the nonlinear optical coefficients, the regenerator can be made much more compact. In particular, self-phase modulation and parametric amplification using cascaded nonlinear optical processes in periodically-poled lithium niobate is of special interest as its effective nonlinear coefficient is approximately 4 orders of magnitude higher than that of optical fiber. So the kilometers of fiber used in the experiments described above as be replaced by a few centimeters of periodically-poled lithium niobate.
While the invention has been described, disclosed, illustrated and shown in various terms of certain embodiments or modifications which it has presumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended.
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All optical regeneration methods and systems can be realized through an exponential amplifier and a limiting amplifier, which could be two independent devices (one piece of fiber with parametric amplification and a semiconductor optical amplifier operating at saturation state) or one single device (one piece of fiber). The signal quality and the extinction ratio after regeneration are significantly improved compared with the degraded incoming data using a parametric amplifier with the data signal to be regenerated as the pump. The regenerated data has an extinction ratio as high as 14 dB, an extinction ratio enhancement of approximately 5 dB and an approximately 5 dB negative power penalty. This regeneration schemes are format transparent (RZ and NRZ), and provide noise reduction both for bit 1' s and bit 0' s of the data sequence. The regeneration method and apparatus that just utilizes fibers has the additional capability of ultrafast response speed (several femtoseconds due to the Kerr effect).
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention herein is a fabric faced fiberboard and, more particularly, an acoustical wallboard.
2. Description of the Prior Art
The basic fabric covered wallboard is shown in U.S. Pat. No. 3,920,872. This is a flat surface wallboard.
The use of a corrugated surface for a ceiling board for acoustical purposes is known in the art.
SUMMARY OF THE INVENTION
A fabric covered board structure comprising a mineral fiber board having good impact resistance due to a board density of at least 1.5 lbs./board foot, and preferably 1.95 lbs./board foot. The board has in part a corrugated face surface of parallel spaced grooves and hills forming a surface area about one and one-third times that of a flat uncorrugated board face surface to yield a sound absorption rating (NRC) of about 0.45. The corrugated face surface being coated with a light discontinuous coating of adhesive having a high tack. A flexible porous textile or vinyl fabric is adhered to the grooves and hills of the corrugated face by the adhesive coating.
The board structure has a face surface devoid of pin holes or other types of mechanically formed acoustical openings.
BRIEF DESCRIPTION OF THE DRAWING
The drawing is an end view in section of a portion of the structure of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The fabric covered board structure 2 of the drawing is composed of a base board 3, with in part a corrugated front face 8, side 10 and back 12, a discontinuous adhesive coating 4, and a fabric 5 covering the corrugated surface. The fabric can be wrapped around the side 10 of the board 3 and held on the back 12 of the board by a strip of adhesive 6 or alternatively only on the side 10.
The base board 3 is a conventional ceiling board such as the "Corrugated Crossgate®" ceiling board sold by Armstrong. This board is of mineral wool construction and formed by a conventional water-laid process on paper making machinery. Since the product can be used on walls it must have some impact resistance to prevent surface damage. The impact resistance is secured by forming the board with a density of at least 1.5 lbs./board foot, and preferably 1.95 lbs./board foot. If fiber glass is used, density could be less and the natural recovery of the board surface functions to give the appearance of impact resistance. Here density could be as low as 0.5 lbs./board foot. The board should provide some sound absorption without punching holes or other acoustical openings in the face of the board. If increased sound absorption is desired, the board can be punched prior to applying the fabric. Since the corrugated surface is cut in the surface of the board, the board will have a surface which is porous to sound and will provide good sound absorption with a rating of NRC=0.45. The corrugated surface appears to help sound absorption since the surface area of the corrugations is 1-1/3 times that of the flat surface of the original board before the corrugations are cut in the face surface of the board.
The fabric covering the corrugations may be a woven or non-woven textile fabric or a porous vinyl fabric. It must be porous to sound so that sound waves will pass through the fabric and be absorbed by the board surface. A preferred fabric is a crepe weave polyester made by Guilford of Me. and sold under the trademark "Corina".
The adhesive is critical to the proper adherence of the fabric to the grooves of the corrugated surface. The adhesive must be applied in a discontinuous coating so the adhesive coating is porous to sound. The coating is sprayed on the corrugated surface as a light coating of about 20 grams/square foot. Typical pressure sensitive or regular adhesives tested did not have sufficient quick and good tack to hold the fabric into the corrugations immediately and permanently after fabric application. An adhesive that has the ability to quickly set up and provide immediate high tack is:
______________________________________Material % by Weight______________________________________Covinax 114 - Vinyl Acrylic Adhesive by 36.0 .sup. Franklin ChemicalCovinax 324 - Vinyl Acrylic Adhesive by 36.0 .sup. Franklin ChemicalDecabromodiphenyl Oxide - fire retardant 20.0Antimony Trioxide - fire retardant 8.0 100.0______________________________________
The adhesive must have the ability to provide a quick and good hold of the adhesive to the fabric when the fabric is placed in the groove so that the fabric will stay in the groove while subject to stresses forcing the rest of the fabric around the adjacent hill. Quick hold means that the fabric and adhesive bind together with less than one second application of pressure. High tack exists with the above adhesive in that after 2 minutes drying after application, the adhesive is sticky to the touch. Other adhesives tested were not sticky to the touch after 2 minutes of drying.
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A fabric covered board structure made with a base of a mineral fiber material having a corrugated face surface. A discontinuous coating of high tack adhesive on the corrugated face surface and a flexible textile or vinyl sheet adhered to the face surface by the adhesive.
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BACKGROUND OF THE INVENTION
The invention relates to a component with a first layer which consists essentially of a first material, a second layer which consists essentially of a second material, and at least one intermediate layer located between the first layer and the second layer.
DESCRIPTION OF THE RELATED ART
A generic component is known from U.S. Pat. No. 5,698,048. In this case, between the two layers there is an intermediate layer which contains a polymer, but not one of the two materials of the layer.
U.S. Pat. No. 5,454,880 discloses a diode in which one layer of a polymer and another layer which contains fullerene lie adjacent to one another. Here the polymer is made such that it acts as a donor while the fullerenes act as acceptors for charge carriers.
SUMMARY OF THE INVENTION
The object of the invention is to devise a generic component which has an efficiency as high as possible for sending and/or receiving electromagnetic radiation, especially light.
In particular, a solar cell with efficiency as high as possible will be created by the invention.
This object is achieved as claimed in the invention by making a generic component such that the intermediate layer contains the first material and/or the second material and that in the intermediate layer a least one material is colloidally dissolved and that the substance has a conductivity different from that first material or the second material.
Therefore the invention calls for devising a component which has at least two layers of two materials with different conductivities and at least one intermediate layer between them. The intermediate layer contains at least one of the two materials and a colloidally dissolved substance. Here colloidally dissolved means that the substance consists of particles or forms them by a chemical reaction or agglomeration and that these particles are located in the material. The particles preferably have a size of 1 nm to 1 microns. Preferably the particles are located in the material such that they form a network via which charge carriers can flow, for example in a percolation mechanism. It is advantageous, but not necessary, that the charge carriers can flow in the material. The colloidally dissolved substance has a conductivity which is different both from the conductivity of the first material and also from the conductivity of the second material. Here it is less a matter of the absolute level of conductivity than of the manner in which the charge carriers are transported.
The first feasible embodiment of the component is characterized in that it contains exactly one intermediate layer. The intermediate layer consists for example of a first material and the substance dissolved therein or of a second material and a substance dissolved therein or of a mixture or compound of the first material with the second material and the substance dissolved therein.
Another, likewise advantageous embodiment of the component is characterized in that between the first layer and the second layer there are a first intermediate layer and a second intermediate layer, that the first intermediate layer adjoins the first layer and that the second intermediate layer adjoins the second layer.
The intermediate layers can be distinguished for example by the first intermediate layer containing essentially the first material and the substance colloidally dissolved therein and by the second intermediate layer consisting essentially of the second material and the substance colloidally dissolved therein.
Furthermore, it is advantageous that in the first intermediate layer a first substance is colloidally dissolved and that in the second intermediate layer a second substance is colloidally dissolved.
An increased current yield or radiation yield is achieved by the first and/or the second material being a semiconductor.
It is especially feasible for the first material and/or the second material to be an organic semiconductor.
For use of the component as a solar cell or as a component of a solar cell it is advantageous for the first material and/or the second material to have suitable light absorption.
Feasibly the organic semiconductor contains substituted perylene pigments. In particular, it is feasible for the perylene pigments to be substituted perylene carboxylic acid imides.
A further increase of the efficiency is achieved by the first material having a type of conductivity different than the second material.
It is especially advantageous that the second material contains an organic complex compound, especially an organometallic complex compound. Here it is preferably a phthalocyanin compound. Use of hydrogen phthalocyanin or metal phthalocyanins, especially zinc phthalocyanin, is especially advantageous.
One preferred embodiment of the component as claimed in the invention is characterized by the substance consisting of a semiconductor material.
The concept semiconductor material comprises all substances known from semiconductor technology as semiconductor materials. The concept of semiconductor material here is however not limited to materials which are generally called semiconductors, but rather comprises all materials which in at least one modification of particle size have a band gap between the valency band and the conduction band. For the charge transport of charge carriers of one type to be achieved what matters is simply the energy position and energy level in the substance. Thus, for example, in the removal of electrons simply one position of the conduction band in the substance which corresponds to the position of the conduction band or of the valency band in the material is necessary. Here the position of the valency band in the substance and thus the band gap are not important. In hole conduction it applies accordingly that the valency band of the substance is feasibly located at an energy level which corresponds to the energy level of the valency band or the conduction band of the material. Examples of the semiconductor material are SnO 2 and TiO 2 .
As a result of quantum size effects the conductivity of the particles of the substance can be different from macroscopic conductivity. For the invention electrical conduction is feasible to the extent by which the charge carriers of one type of conductivity can be removed on a controlled basis. An increase of conductivity by a suitable nanostructure by which for example one substance which macroscopically forms a semiconductor acts as a metal in the layer as claimed in the invention is therefore included at the same time. This also applies to macroscopically metallic materials which as small particles become semiconductors.
One preferred embodiment of the component is characterized by the substance consisting of an organic semiconductor material.
In particular it is feasible for the substance to contain a carbon modification, the carbon modification having a band gap, like for example C 60 , C 70 or graphene.
Especially effective charge transport with simultaneous prevention of electrical short circuits is achieved by the substance being present essentially in the form of particles.
The particles are for example individual molecules, especially individual fullerene molecules, or clusters of several molecules.
The particles preferably have a size from 1 nm to 1 micron, an upper particle size of 200 nm being preferred.
A clear increase of charge transport is achieved in that particles have a concentration which is so great that percolation is formed.
A further increase of efficiency in sending and/or receiving electromagnetic radiation can be achieved by spatially varying the concentration of the substance.
This version of the invention therefore calls for devising a component which has an intermediate layer within which the concentration of a colloidally dissolved substance varies spatially.
The intermediate layer is located between the first layer and the second layer, its being possible that these layers are located within a common carrier material. The first and the second layer can differ both little from one another and can also consist of completely different materials.
Preferably the first and the second material differ simply in that they are doped differently.
One feasible embodiment of the component is characterized in that the concentration of the substance varies within the intermediate layer.
It is especially feasible for the component to be made such that there are at least two substances in the intermediate layer.
Furthermore, it is advantageous for one of the substances to have a concentration which varies spatially differently from the concentration of the other substance.
One feasible embodiment of the component is characterized by the first substance having a Fermi level which differs by at least 20 meV from the Fermi level of the second substance.
Furthermore, it is advantageous that the first substance has a different type of conductivity than the other substance.
One feasible embodiment of the component is characterized in that the one substance has a band gap different from the first substance.
Furthermore, it is advantageous that the band gap of the first substance differs from the band gap of the second substance by at least 20 meV.
BRIEF DESCRIPTION OF THE DRAWINGS
Other advantages, particulars and feasible developments of the invention follow from the dependent claims and the following description of one preferred embodiment using the drawings.
FIG. 1 shows a cross section through a first embodiment of the component as claimed in the invention,
FIG. 2 shows the external quantum yield as incident photon to current efficiency (IPCE) as a function of the wavelength of the incident light for various concentrations of C 60 ,
FIG. 3 shows a cross section through a second embodiment of a component as claimed in the invention,
FIG. 4 shows a cross section through another embodiment of a component as claimed in the invention,
FIG. 5 shows the concentration of the first dopant as a function of its distance to the region of the first layer and
FIG. 6 shows the concentration of the second dopant as a function of its distance to the region of the first layer.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The component shown in FIG. 1 is for example a solar cell or an organic light emitting diode. The component contains a layer system applied to a substrate 10 , for example glass, especially silicate glass, consisting of a transparent contact layer 20 , a first layer 30 , a second layer 60 , an intermediate layer 50 and a contact-making layer 70 .
A contact 80 is applied to the side region of the transparent contact layer 20 . Another contact 80 is located on the upper contact-making layer 70 . The transparent contact layer 20 has a thickness between 5 nm and 1 micron, preferably 10 nm to 20 nm. The thickness of the contact layer 20 can be chosen to be variable.
The first layer 30 is located on the transparent contact layer. It is possible for the first layer 30 to extend in sections to the substrate 10 as well, for example, in regions in which the transparent contact layer 20 was etched away beforehand. To achieve interface effects between the transparent contact layer 20 and the first layer 30 this is however not necessary.
But it is a good idea for production engineering for the first layer 30 to project over the transparent contact layer 20 , because in this way a short circuit is avoided between the contact 90 and the transparent contact layer 20 .
The first layer 30 has a thickness between 5 nm and 1000 nm, preferably 10 nm to 200 nm. The thickness of the layer 30 can be chosen to be variable because to achieve interface effects between the layers 30 and 60 the dimensions of the layers 30 , 60 are not important.
The contact layer 20 consists preferably of a transparent material which is especially a transparent conductive oxide. The transparent properties are necessary in an application as a solar cell or as a light emitting diode with light which penetrates through the substrate 10 , so that the light rays penetrating through the substrate 10 are not absorbed by the contact layer 20 . For light incidence or emergence through the layer 60 it is not necessary to make the contact layer 20 transparent.
The first layer 30 consists preferably of an organic semiconductor of the first type of conductivity. For example it is an n-conductive material, preferably perylene-3,4,9,10-tetracarboxylic acid-N,N′-dimethylimide (MPP).
The second layer 60 consists preferably of a second semiconductor layer. Here it is especially a material with the opposite type of conductivity, preferably zinc phthalocyanin (ZnPc). A contact-making layer 70 is used for electrical connection of the layer 60 . For example, the contact-making layer 70 consists of gold. Gold has the special advantage that it combines high conductivity with high chemical stability.
The intermediate layer 50 contains the same material as the layer 60 , but is enriched with a fullerene or a semiconductor oxide such as TiO 2 . When using the component as a solar cell, the enrichment is preferably a maximum 60%. When the component is used as a light emitting diode the enrichment can be even higher.
FIG. 2 shows solar current yields by external quantum yield as the incident photon to current efficiency (IPCE) as a function of the wavelength of the incident light for different concentrations of C 60 .
Here they are the measured values which were measured for the solar cell shown in FIG. 1 . It appears that the current yield increases with the increasing concentration of C 60 . An especially great rise occurs at a concentration of C 60 of more than 10%. One possible explanation for this unexpectedly high rise could be the occurrence of percolation.
The component shown in FIG. 1 is for example a solar cell or an organic light emitting diode. The component contains a layer system applied to a substrate 10 , for example glass, especially silicate glass, consisting of a transparent contact layer 20 , a first layer 30 , a second layer 60 , a first intermediate layer 40 , a second intermediate layer 50 and a contact-making layer 70 .
A contact 80 is applied to the side region of the transparent contact layer 20 . Another contact 90 is located on the upper contact-making layer 70 . The transparent contact layer 20 has a thickness between 5 nm and 1000 nm, preferably 10 nm to 200 nm. The thickness of the layer can be chosen to be variable.
The first layer 30 is located on the transparent contact layer. It is possible for the first layer 30 to extend in sections to the substrate 10 as well, for example, in regions in which the transparent contact layer 20 was etched away beforehand.
It is a good idea for production engineering for the first layer 30 to project over the transparent contact layer 20 , because in this way a short circuit is avoided between the contact 90 and the transparent contact layer 20 .
The first layer 30 has a thickness between 5 nm and 1000 nm, preferably 10 nm to 200 nm. The thickness of the layer can be chosen to be variable because to achieve the interface effects the dimensions of the layers are not important.
The contact layer 20 consists of a transparent material which is especially a transparent conductive oxide in an application as a solar cell with light incidence through the substrate 10 or as a light emitting diode with light emergence through the substrate 10 .
In the embodiment shown using FIG. 1 the first layer 30 consists preferably of an organic semiconductor material of the first type of conductivity. For example, it is an n-conductive material, preferably perylene-3,4,9,10-tetracarboxylic acid N,N′-dimethylimide (MPP).
The second layer 60 consists preferably of a second semiconductor material. Here it is especially a material with the opposite type of conductivity, preferably zinc phthalocyanin (ZnPc). A contact-making layer 70 is used for electrical connection of the layer 60 . For example, the contact-making layer 70 consists of gold. Gold has the special advantage that it combines high electrical conductivity with high chemical stability.
The first intermediate layer 40 contains in any case the material contained in the first layer 30 and possibly also the material contained in the second layer 60 , preferably at least one organic semiconductor. NPP or ZnPc are especially suited. Furthermore, the intermediate layer 40 is enriched with a fullerene or another semiconductor material such as TiO 2 . When using the component as a solar cell the enrichment is preferably a maximum 60%. When the component is used as a light emitting diode the enrichment can be even higher.
The second intermediate layer 50 contains the same material as the layer 60 , but is enriched with another fullerene or a semiconductor material such as TiO 2 . When using the component as a solar cell the enrichment is preferably a maximum 60%. When the component is used as a light emitting diode the enrichment can be even higher.
The component shown in FIG. 4 is for example a solar cell or an organic light emitting diode. The component contains a layer system applied to a substrate 10 , for example glass, especially silicate glass, consisting of a transparent contact layer 20 , a multiple layer and a contact-making layer 70 . The multiple layer consists preferably of a first layer 30 , a second layer 60 , and an intermediate layer 40 .
A contact 80 is applied to the side region of the transparent contact layer 20 . Another contact 90 is located on the upper contact-making layer 70 . The transparent contact layer 20 has a thickness between 5 nm and 1 micron, preferably 10 nm to 200 nm. The thickness of the contact layer 20 can be chosen to be variable.
The first layer 30 is located on the transparent contact layer. It is possible for the first layer 30 to extend in sections to the substrate 10 as well, for example, in regions in which the transparent contact layer 20 was etched away beforehand. To achieve interface effects between the transparent contact layer 20 and the first layer 30 this is however not necessary.
But it is a good idea for production engineering for the first layer 30 to project over the transparent contact layer 20 , because in this way a short circuit is avoided between the contact 90 and the transparent contact layer 20 .
The first layer 30 has a thickness between 5 nm and 1000 nm, preferably 10 nm to 200 nm. The thickness of the layer can be chosen to be variable because to achieve interface effects between the layers 30 and 60 the dimensions of the layers 30 , 60 are not important.
The contact layer 20 consists preferably of a transparent material which is especially a transparent conductive oxide. The transparent properties are necessary in an application as a solar cell or as a light emitting diode with light which penetrates through the substrate 10 , so that the light rays penetrating through the substrate 10 are not absorbed by the contact layer 20 . For light incidence or emergence through the layer 60 it is not necessary to make the contact layer 20 transparent.
The layer 30 consists essentially of a matrix material and a semiconductor colloidally dissolved therein. The semiconductor preferably has the first type of conductivity. For example, it is an n-conductive material, preferably cadmium sulfide (CdS), n-doped gallium arsenide (GaAs), n-doped silicon, n-doped cadmium tellurite (CdTe) or a substituted perylene pigment, especially a methylene-substituted perylene pigment, especially perylene-3,4,9,10-tetracarboxylic acid-N,N′-dimethylimide (MPP).
The second layer 60 consists preferably of a matrix material and a semiconductor material colloidally dissolved therein. The second semiconductor material is especially a material with a type of conductivity opposite the first semiconductor material, for example, p-doped zinc phthalocyanin (ZnPc), p-doped gallium arsenide (GaAs) or p-doped silicon.
A contact-making layer 70 is used for electrical connection of the layer 60 . For example, the contact-making layer 70 consists of gold to achieve high electrical conductivity and high chemical stability.
Between the first layer 30 and the second layer 60 there is at least one intermediate layer 40 . The intermediate layer 40 contains a suitable matrix material. When the layer 30 has the same matrix material as the layer 60 , it is a good idea for the intermediate layer 40 to also consist of this matrix material. If, which is likewise possible, the layer 30 has a different matrix material than the layer 60 , it is preferably for the intermediate layer 40 to consist of a mixture or a solution of matrix material with one or more substances colloidally dissolved therein.
The multiple layer is produced by alternating immersion in solutions of different concentrations. In this way the layers which form the multiple layer are deposited in succession.
In one preferred implementation of the process a system of layers is deposited on the substrate 10 as follows: Wetting, especially dip-coating, for example of indium tin oxide (ITO), is done with a colloidal, especially aqueous solution of particles, for example CdTe particles first, the substrate 10 being immersed in succession in solutions of various concentrations. The lengths of immersion and pulling speeds are varied such that first only CdTe particles, then mixtures with variable composition, then pure CdS particles build up the layer.
The colloidal solution from which the layers are deposited by dip coating can contain a stabilizer, but this is not necessary. One preferred stabilizer is polysulfate which in solution forms a jacket around the particles which prevents them from coalescing. When the layers are deposited the stabilizer forms a matrix material in which the particles are embedded.
If the colloidal solution does not contain a stabilizer, there is a space charge zone—ionic layer—around the particles, with charges which prevent the particles from coalescing. The ions in the space charge zone are incorporated into the deposited layer at the same time during deposition.
FIG. 5 shows the concentration of a first dopant as a function of its distance to the region of the first layer 30 . The first dopant is for example CdTe. In a region of roughly 100 microns the concentration of the first dopant decreases largely linearly.
By means of a largely linear decrease of the concentration of the first dopant there is an essentially constant concentration gradient in the roughly 100 micron wide area for the first dopant.
FIG. 6 shows the concentration of the second dopant as a function of its distance to the region of the first layer 30 . The second dopant is for example CdS. In a region of roughly 100 microns the concentration of the second dopant increases largely linearly.
By means of a largely linear increase of the concentration of the second dopant there is likewise an essentially constant concentration gradient in a roughly 100 micron wide area for the second dopant.
In the especially preferred case which is shown, the concentration gradients of the dopants differ only by their sign.
The concentration variation shown in FIGS. 5 and 6 is preferred; the preferred embodiments of the invention with a changing concentration are however in no way limited to linear concentration changes.
Reference Number List
10 substrate
20 contact layer
30 first layer
40 first intermediate layer
50 second intermediate layer
60 second layer
70 contact-making layer
80 contact
90 contact
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A component with a first layer which mainly includes a first material, a second layer which mainly includes a second material and at least one intermediate layer being located between the first layer and the second layer. The component is configured in such a way that the intermediate layer contains the first and/or the second material and that at least one substance is colloidally dissolved in the intermediate layer and that the substance has another conductibility than the first or second material.
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BACKGROUND OF THE INVENTION
This invention relates to a yarn which has been treated with a lubricant and soil release finish composition prior to fabric formation, particularly to a yarn which has been treated with an oil-in-water emulsion finish.
Prior to fabric formation, synthetic yarn and yarn blends containing synthetic fibers are typically processed to provide increased strength, stretch and bulk, and to enhance their appearance. The processing steps may include heating and drawing to provide a degree of orientation to the yarns, as well as texturing with mechanical action. After the yarns have been modified as desired, a lubricant is applied to reduce friction during subsequent processing steps, such as winding, weaving or knitting.
It is well known to improve the washability and moisture transport properties of fabrics made from synthetic fibers by treating the fabric with a "soil release agent". In one example, a soil release agent, which is the condensation product of dimethyl terephthalate, ethylene glycol and polyethylene glycol, is added to the bath during jet dyeing of polyester, and the agent is exhausted into the fibers of the fabric. Following the dyeing step, the fabric is rinsed, dried and heat set.
One of the shortcomings of the prior art process is that the soil release agent is applied to the fabric during the dye cycle. Accordingly, it has been necessary to process the fabric in the dyeing equipment, even if the fabric is not going to be dyed, for the sole purpose of providing the soil release treatment. Another shortcoming is that it is that the soil release agent is applied after fabric formation. Accordingly, when the yarn is sent to different locations to be woven or knitted, or if the yarn is sold, each location is required to have its own equipment for applying the soil release agent.
SUMMARY OF THE INVENTION
Therefore, one of the objects of the invention is to provide a soil release treatment which need not be exhausted into the fabric. Another object of the invention is to provide a soil release treatment which may be applied to the yarns prior to fabric formation. Still another object of the invention is to combine application of the lubricant finish and soil release finish in a single step.
Accordingly, a finish composition is provided, which incorporates a lubricating oil and a soil release agent and is applied to a yarn as an oil-in-water emulsion. The lubricant protects the yarn during subsequent processing steps, such as winding and fabric formation. The soil release agent improves the washability and moisture transport properties of the yarn and fabrics made therefrom.
Additionally, the invention may be characterized by one or more of the following features:
yarn to yarn friction of 33 to 39 grams of output tension;
yarn to metal friction of less than 50 grams of output tension at a contact angle of 180°; and
textured continuous filament polyester yarn.
Advantages of the present invention include:
a decrease in the amount of lubricant required, as the soil release agent provides lubrication to the yarn; and
elimination of unnecessary process steps, since the soil release properties may be imparted to a yarn by application of a soil release agent under ambient conditions.
DETAILED DESCRIPTION OF THE INVENTION
Without limiting the scope of the invention, the preferred embodiments and features are hereinafter set forth. Unless otherwise indicated, all parts and percentages are by weight and conditions are ambient i.e. one atmosphere of pressure and 25° C. The terms aryl and arylene are intended to be limited to single and fused double ring aromatic hydrocarbons. Unless otherwise specified, aliphatic hydrocarbons are from 1 to 12 carbon atoms in length, and cycloaliphatic hydrocarbons comprise from 3 to 8 carbon atoms.
In the present invention, the soil release agent is applied to a yarn, prior to fabric formation, along with a lubricant. The yarn may be a continuous multifilament yarn or spun yarn. The yarn will typically have a denier ranging from 30-300 and have a filament count ranging from 10-200, preferably 15-100. The denier and the filament count are not deemed to be critical to the practice of the invention, and yarns outside the stated ranges may be used.
A wide variety of natural and synthetic fibers may be employed. By way of example the fiber substrate may be selected from polyamide fibers, including nylon, such as nylon 6 and nylon 6,6, and aramid fibers; polyester fibers, such as polyethylene terephthalate (PET); polyolefin fibers, such as polypropylene; polyurethane fibers; blends of the aforementioned synthetic fibers; and blends of such synthetic fibers with cellulosic fibers, such as cotton, rayon and acetate. Preferably, the fiber has a hydrophobic component and is selected from polyamide fibers, polyester fibers or polyester/cotton blends.
The finish composition applied to the yarn contains a lubricating oil to facilitate subsequent processing of the yarn, such as winding, warping and fabric formation, and a soil release agent to enhance the performance of the textile article made from the yarn. The finish composition is applied to achieve a lubricant add on, including emulsifiers necessary to form a stable emulsion, of from 0.15 to 6 wt % on the weight of the fiber (owf), preferably 0.375 to 2% owf; and a soil release agent add on of from 0.05 to 3.0% owf, preferably 0.075 to 0.75% owf.
Satisfactory results are achieved with emulsions containing 45 wt % or greater, preferably, 50 wt % or greater water and compositions having the following ranges may be employed:
1 to 49.7 wt. % of a lubricating oil;
0.3 to 49 wt. % of a soil release agent;
50 to 95 wt. % water; and
up to 5 wt. % auxiliaries.
Preferably, the composition is an emulsion having from:
2.5 to 29.5 wt. % of a lubricating oil;
0.5 to 25 wt. % of a soil release agent;
70 to 95 wt. % water; and
up to 3 wt. % auxiliaries. The concentration of lubricating oils is intended to include the emulsifiers necessary to form a stable emulsion of the oil.
The auxiliaries biocides, antistatic agents, anti-sling agents, and wetting agents, and their use in fiber finishes well known to those skilled in the art.
The invention may be practiced with a wide variety of conventional lubricating oils. By way of example, suitable oils include:
(a) mineral oil derivatives which include paraffinic, alicyclic and aromatic hydrocarbons and combinations thereof; the molecular weights of the mineral oils typically range from 175-1000;
(b) synthetic oils including:
(i) organic esters such as C 6 -C 18 esters of fatty acids, particularly dibasic esters derived from C 6 -C 10 diacids esterified with C 6 -C 10 alcohols and esters of higher polyols such as triglycerides and esters of pentaerythritol;
(ii) alkoxylated fatty acids and alcohols, primarily propylene oxide and ethylene oxide adducts of C 10 -C 18 organic acids and alcohols;
(iii) low molecular weight polyolefins, which are liquid at ambient conditions, such as polyisobutylene and polyalphaolefins; and
(iv) silihydrocarbon oils.
Reference may be made to the Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd Edition, Volume 14, page 477 et. seq. "Lubrication and Lubricants" (1981); Ross et at, U.S. Pat. No. 4,995,884; and Plonsker, U.S. Pat. No. 4,932,976.
Conventional soil release agents may be employed in the composition of the present invention. The soil release agents are characterized by a macromolecule having a hydrophilic component, such as a carboxyl, hydroxyl, alkali metal sulfonate and/or oxyethylene group, and a lipophilic component with an affinity for the fiber, which functions to add durability or to anchor the soil release agent to the fiber surface. The backbone of the macromolecule is generally formed by either vinyl polymerization or condensation reaction. Molecular weights may range from 500 to 100,000, preferably from 1,000 to 25,000, most preferably 1,000 to 10,000.
By way of example, suitable soil release agents include:
(a) non-ionic soil release agents having oxyethylene hydrophiles, such as the condensation polymers of polyethylene glycol and/or ethylene oxide addition products of acids, amines, phenols and alcohols which may be monofunctional or polyfunctional, together with binder molecules capable of reacting with the hydroxyl groups of compounds with a poly(oxyalkylene) chain, such as organic acids and esters, isocyanates, compounds with N-methyl and N-methoxy groups, bisepoxides etc. Particularly useful are the condensation products of dimethyl terphthalate, ethylene glycol and polyethylene glycol (ethoxylated polyester) and ethoxylated polyamides, especially ethoxylated polyesters and polyamides having a molecular weight of at least 500, as well as the soil release agents described in the following patents, U.S. Pat. No. 3,416,952; U.S. Pat. No. 3,660,010; U.S. Pat. No. 3,676,052, U.S. Pat. No. 3,981,807; U.S. Pat. No. 3,625,754; U.S. Pat. No. 4,014,857; U.S. Pat. No. 4,207,071; U.S. Pat. NO. 4,290,765; U.S. Pat. No. 4,068,035 and U.S. Pat. No. 4,937,277.
(b) anionic soil release agents particularly, vinyl polymers containing carboxylic acid as the hydrophile as can be obtained by polymerizing acrylic acid, methacrylic acid or maleic acid, usually with a comonomer such as an alkyl acrylate, preferably methyl or ethyl acrylate, to increase the lipophilic character of the polymer and to decrease brittleness. Cross-linking improves the durability of the soil release agent, and accordingly, it is desirable to copolymerize with a cross-linking agent such as N-methyl acrylamide, or to cross-link the polymer with a small amount of a bisepoxide. Examples of representative anionic soil release agents may be found in the following patents: U.S. Pat. No. 3,377,249; U.S. Pat. No. 3,535,141; U.S. Pat. No. 3,540,835; U.S. Pat. No. 3,563,795; U.S. Pat. No. 3,598,641; U.S. Pat. No. 3,574,620; U.S. Pat. No. 3,632,420; U.S. Pat. No. 3,650,801; U.S. Pat. No. 3,652,212; U.S. Pat. No. 3,690,942; U.S. Pat. No. 3,897,206; U.S. Pat. No. 4,090,844; and U.S. Pat. No. 4,131,550.
(c) combinations of anionic soil release agents with oxyethylene hydrophile condensates, such as are generally referred to as sulfonated ethoxylated polyesters and the soil release agents disclosed in the following patents: U.S. Pat. No. 3,649,165; U.S. Pat. No. 4,073,993; and U.S. Pat. No. 4,427,557.
(d) nonionic soil release agents with hydroxyl hydrophiles, particularly cellulose derivatives such as cellulose acetate and the soil release agents disclosed in the following patents: U.S. Pat. No. 3,620,826; U.S. Pat. No. 4,164,392; and U.S. Pat. No. 4,168,954.
The soil release agent may be in the form of an emulsion, dispersion or solution. Preferably, the soil release agent has a nonionic hydrophilic component and is in the form of an aqueous dispersion or aqueous solution.
All of the United States patents heretofore listed are incorporated by reference herein.
The lubricating oil and soil release agent are combined, along with the desired ancillary additives, to form an oil-in-water emulsion using conventional techniques. Preferably, the soil release agent is in the form of an aqueous dispersion, solution or emulsion, as are commercially available. For example, first an emulsion of the lubricant and water is formed by vigorous agitation with a laboratory stirrer, and next, the soil release agent may be added while continuing to agitate the composition. It may be desirable to improve the stability of the emulsion by incorporating surface active agents (surfactants) or emulsifiers into the composition, as is well known to those skilled in the art. Suitable emulsifiers include nonionic, ionic and zwitterionic surfactants, such as alkoxylated alcohols, alkyl phenols, fatty acids and amides; carboxylate, sulfonates and phosphate esters, quaternary compounds and those surfactants disclosed in the Kirk-Othmer Encyclopedia of Chemical Technology, 3rd Edition, Surfactants and Detersive Systems, pp. 332-432 (1983). If an emulsifier is necessary to stabilize the finish composition, the emulsifier may be employed at a ratio of emulsifier to oil of from about 1:20 to 2:1, preferably 1:10 to 1:1.
The lubricant/soil release finish composition may be applied at any stage of yarn processing that a lubricant alone could be applied. Prior to application of the finish, the yarn may be subjected to various treatments, such as one or more of the following: drawing, twisting, heat setting, entanglement or crimping. In a preferred embodiment, the finish is applied at the texturing frame to textured polyester yarn made from drawn partially oriented yarn (POY).
The finish may be applied by conventional techniques used to apply a lubricant emulsion to yarn. By way of example, the finish of the present invention may be applied from a kiss roll, metered applicator, sprayer, or by immersion. The add on of finish composition (as is) ranges from 1 to 30 wt. % owf, preferably from 3 to 15 wt. % owf, most preferably from 3 to 8 wt% owf.
Following application of the present finish to the yarn, the yarn may be handled and processed as are yarns treated with conventional lubricants. For example, the yarn may be wound into a package and then formed into a fabric, preferably a woven knitted fabric, as is well known in the art. The yarn or fabric may be scoured, heat set and even dyed. One of the advantages of the present process is that it is particularly useful when the yarn or fabric is not dyed. Since the soil release agent is applied early in the yarn processing process, the dyeing step can be eliminated when it is desirable to do so. Surprisingly, the performance and durability of the soil release treatment is not adversely affected by omission of the dyeing step, or other treatment in a heated aqueous bath, which was once thought necessary to exhaust the soil release agent into the fiber, before soil release properties could be achieved.
The invention may be further understood by reference to the following examples, but the invention is not to be construed as being unduly limited thereby.
EXAMPLE 1
The following example demonstrates the washability and moisture transport performance of a fabric constructed of yarn, which has been treated with the lubricant/soil release agent emulsion of the present invention.
A partially oriented polyester yarn, 150/34, was heated, drawn and textured. At the texturing frame, a lubricant/soil release agent finish was applied in emulsion form to the yarn to achieve 1 wt %, 2 wt % or 3 wt % (owf), on a neat basis. The composition of the finish was 3.2 wt % of an ethoxylated polyester soil release agent identified as lubril QCX™ available from Rhone Polenc; 20 wt % of an emulsified ester lubricant, identified as Synlube™ 6340 available from Milliken Chemical, U.S.A.; and 76.8 wt % water.
For each level of finish, the yarn was knitted into a sock and the sock was cut in half. One half of the sock was scoured in a 120° F. home wash (12 minute "cotton/sturdy" wash cycle in a residential washing machine with detergent present). The scoured and unscoured halves of fabric, Samples A and B, respectively, were then dyed blue (Resolin Blue GFL) in a disperse dye cycle (130° C. for 30 minutes) on a Mathis laboratory jet dyeing machine.
The fabrics were then tested for soil release using corn oil according to AATCC Test Method 130-1977, and moisture transport according to AATCC Test Method 39-1977. The soil release test is designed to measure the ability of a fabric to release oily stains during home laundering. Briefly, a sample fabric is stained with corn oil and washed under conventional home laundry conditions. The samples are then rated on a scale from 1-5, with 1 representing the poorest stain removal and 5 representing the best stain removal.
The moisture transport or wettability test measures the time it takes for a fabric to absorb a drop of water, while the fabric is held taut and horizontal. The time it takes for the drop to completely absorb into the fabric is measured in seconds, with a stop watch, and recorded. A high number is indicative of slow absorption, and thus poor wettability. The fabric made from yarn treated with the lubricant/soil release agent finish of the present invention were compared to fabrics made from yarn treated with a lubricant finish only, which was knitted, cut in half and one half only was scoured, Samples C and D. The results for 1 wt % (owf) finish levels are reported in Table 1.
TABLE 1______________________________________ Finish Finish Soil Release WettabilitySample Treatment Level Scour? Rating (1-5) (Seconds)______________________________________A lubricant/soil 1 wt % scour 4.5 1 release agent (owf)B lubricant/soil 1 wt % no scour 4.8 1 release agent (owf)C lubricant 1 wt % scour 2.8 >30 (owf)D lubricant 1 wt % no scour 3.0 >30 (owf)______________________________________
EXAMPLE 2
The procedures of Example 1 were repeated except that an equal amount of an emulsified hydrocarbon lubricant, identified as Lube Stat™ 5101 available from Milliken Chemical, U.S.A., was substituted for the lubricant in the lubricant/soil release agent finish. The results of finish applications at 1 wt %, 2 wt % and 3 wt % (owf), on a neat basis, are reported below in Table 2.
EXAMPLE 3
The procedures of Example 1 were repeated except that an alkoxylated lubricant, identified as Syn Lube™ 6278, available from Milliken Chemical, U.S.A., was substituted for the lubricant in the lubricant/soil release agent finish. The results of finish applications at 1 wt %, 2 wt % and 3 wt % (owf), on a neat basis, are reported below in Table 2.
TABLE 2______________________________________Finish Composition(Sample) Add On (owf) Soil Release Rating (1-5)______________________________________Example 1 1 wt % 4.5(Sample A) 2 wt % 5.0 3 wt % 4.8Example 2 1 wt % 5.0 2 wt % 5.0 3 wt % 5.0Example 3 1 wt % 5.0 2 wt % 5.0 3 wt % 5.0______________________________________
EXAMPLE 4
The following example shows variation of the relative proportion of lubricant, soil release agent in water, and the affect the variation has on friction and soil release properties.
The procedures of Example 1 were repeated, except that the components of the lubricant/soil release agent finish of Example 1 was varied as shown in Table 3 below, and designated E, F and G. Also included in Table 3 are the test results for Sample A of Example 1, and the test results for a control yarn which had been treated with a producer supplied primary lubricant finish at approximately 0.3 wt % owf.
Yarn-to-metal and yarn-to-yarn friction was evaluated using a Rothschild frictometer. The finish composition was applied to 150 denier/34 filament, textured polyester yarn, at a conventional texturing frame, at the level specified. The yarn was allowed to condition for at least 24 hours at 72° F. and 63% humidity. After conditioning, the hydrodynamic yarn-to-metal friction was obtained on the frictometer at a speed of 100 meters/minute at a contact angel of 180° and pre-tensions of 20 grams, Yarn-to-yarn friction was evaluated at the above conditions, with the exception that the friction pin was bypassed and the yarn was given two full twists.
TABLE 3__________________________________________________________________________Add On Lubricant Soil Release Water Yarn to Yarn to Soil ReleaseSample(owf) (wt %) Agent (wt %) (wt %) Yarn Friction Metal Friction (1 poorest-5__________________________________________________________________________ best)A 1 wt % 20 3.2 76.8 33 33.5 4.52 wt % 20 3.2 76.8 31 26.5 53 wt % 20 3.2 76.8 32 26.5 4.8E 1 wt % 15 3.75 81.25 40 47 52 wt % 15 3.75 81.25 34 31 53 wt % 15 3.75 81.25 33 28.5 5F 1 wt % 10 4.5 85.5 38 44.5 52 wt % 10 4.5 85.5 33 33.5 53 wt % 10 4.5 85.5 33 29.5 5G 1 wt % 5 5.3 89.7 36 44.5 52 wt % 5 5.3 89.7 34 34.5 53 wt % 5 5.3 89.7 34 31.5 5Control-- -- -- -- 42.5 34.5 1__________________________________________________________________________
EXAMPLE 5
The following example demonstrates the efficacy of the lubricant/soil release composition on an undyed textile.
The lubricant/soil release composition of Sample A and G were applied at levels of 1, 2 or 4 wt % (owf), on a neat basis, to a polyester yarn, 150/34, made from recycled polyethylene terephthalate fiber.
The treated yarn was then knitted into a sock and test for soil release according to AATCC Test Method 130-1977. The results were compared against a control fabric made with yarn to which only a primary finish had been applied, i.e. lubricant only at about 1 wt % (owf) on a neat basis. The results are summarized below in Table 4, with a Soil Release Rating of "5" being the best and "1" being the poorest.
TABLE 4______________________________________Sample Add On (owf) Soil Release (1-5)______________________________________Control Primary Finish Only 3.0A 1% 3.5A 2% 4.5A 4% 5.0G 1% 3.5G 2% 5.0G 4% 5.0______________________________________
There are, of course, many alternative embodiments and modifications of the invention which are intended to be included within the scope of the following claims.
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An improved textile yarn finish is provided having a continuous aqueous phase with a soil release agent incorporated therein and a discontinuous phase of a lubricating oil.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to the construction of thrust blocks for use with fluid piping systems. More particularly, the present invention relates to an apparatus and system for forming a thrust block for use with fittings in pressurized underground fluid pipelines.
[0003] 2. Description of Related Art
[0004] Thrust blocks are commonly used in construction to support large forces. In pressurized piping networks, such as those found in municipal water, irrigation, and waste piping systems, thrust blocks are commonly used to prevent pipeline fittings from moving, yet allow the pipe to move or flex within the joint in response to variation in temperature or slight ground movement. Thrust blocks are used in certain piping systems at all points of direction change, points of size change, and points of termination.
[0005] When forming a thrust block in a piping system, the union of a thrust block to a pipeline fitting should meet three criteria:
[0006] The thrust block must provide sufficient bearing surface area on the outer shape of the pipeline fitting, as determined by the strength of the pipe fitting, and should not include any portion of the bell gasket housing;
[0007] The thrust block should not create concentrated loads or friction wear on the fitting during normal flexing movement of the pipeline; and
[0008] The thrust block should not interfere with the flexing motion between the pipe and the fitting.
[0009] The size of a thrust block is defined by the cross-sectional surface area against undisturbed soil. The minimum required size is based upon four parameters:
[0010] Bearing strength of the soil—the ability for the undisturbed soil to resist movement. Bearing strength is typically measured in lbs/ft 2 (psf). Bearing loads may be as low as 0 psf for muck, peat, etc. and may reach 10,000 psf for hard shale.
[0011] Internal pressure of the piping system—the forces that a thrust block must resist are directly proportional to the internal pipeline pressure. Pipeline pressure is usually measured in psi.
[0012] Size of the piping system—the internal pipeline pressure (psi) acts on the cross sectional of the pipeline fitting (in 2 ) to create a thrust force (pounds) on the pipeline fitting.
[0013] Configuration of the fitting—tee fittings, bends, crosses, offsets, valves, and ends are common fittings, and each fitting is associated with forces exerted on the pipeline. Force vectors and their resulting sum, determine the magnitude and direction of the resultant fitting thrust force.
[0014] Through common engineering calculations or tables, one can obtain the aggregate minimum surface area required based on the four parameters of soil bearing strength, maximum internal pressure, fitting configuration, and fitting size.
[0015] Creating a standardized and adjustable form mold for creating a thrust block is hindered by unique measurements and shapes between the pipeline fitting and the undisturbed trench wall that must be used to resist the fitting thrust forces. The undisturbed trench wall of each thrust block site has a unique shape. The dimensions between the fitting and the undisturbed trench wall are also unique for each excavation site. Custom fabrication of forms for containing the concrete pour forming the thrust block is expensive in labor and materials.
[0016] It is not uncommon for thrust blocks to be poured without fabricated forms. The result is excessive and uncontained concrete. The ability for an inspector to determine if the thrust block meets the minimum required surface area is diminished. The resulting thrust block is without dimensional control or measurement. Excessive concrete use is normal to insure thrust force restraint. In addition to excessive concrete to insure adequate thrust restraint, a significant amount of uncontained concrete forms in areas and places that do not contribute to the resistance of thrust forces.
[0017] Further, if concrete forms over the bell gasket housing or ring-type seal joints, the usefulness and intended design flexibility of the joint is reduced or eliminated. Lastly, excessive use of concrete can result in the inadvertent burial of cables or other items sharing a trench with the pipeline.
[0018] It is therefore desirable to provide a means to construct a thrust block for use with underground pipeline fittings. It is further desirable to provide a means for determining the correct minimum size of a thrust block for a specific application. It is therefore desirable to reduce the time necessary to determine the correct size of a thrust block
[0019] It is also desirable to provide a means to adjust and adapt a form for constructing a thrust block to the unique measurements and shapes between the pipeline fitting and the undisturbed earth of the trench wall.
[0020] It is also desirable to provide a means for constructing a thrust block that is less expensive than custom manufacturing each thrust block form. It is further desirable to provide a means for reducing the material and labor necessary to construct a thrust block form.
[0021] It is further desirable to provide a means for controlling the amount and placement of concrete that is needed to construct a thrust block used with underground pipelines and piping systems. It is therefore desirable to provide a means for controlling and constraining concrete poured around pipeline fittings in a trench.
BRIEF SUMMARY OF THE INVENTION
[0022] The present invention provides means to adapt, indicate, and establish a size of a thrust block for use in pressurized piping systems.
[0023] In one broad respect, the present invention is directed to a thrust block form able to adapt a measurable thrust block form to the unique and variable nature of the area between the pipeline fitting placement and the undisturbed trench wall.
[0024] In one broad respect, the present invention is directed to a thrust block form able to conform to a fitting and adapted for use with fittings of various configurations within a given nominal size. Some common configurations of pipe fittings that can be accommodated include tee fittings, 90° bend fittings, 45° bend fittings, 22.5° bend fittings, 11.25° bend fittings, and end fittings.
[0025] The preferred embodiment of the invention is a pour-in-place form that is disposable and left in place. The invention comprises an inexpensive, semi-rigid material. In some embodiments, the invention is constructed of cardboard.
[0026] The device includes a semi-rigid sheet having an aperture. The semi-rigid sheet is foldable into a mold form between the pipeline fitting and the undisturbed earthen trench wall. The aperture is edged by a deformable lip for closely conforming to the outer shape of the body of the pipeline fitting. The lip may be notched.
[0027] In a more preferred embodiment of the present invention, the device also includes semi-rigid wing members, wherein the semi-rigid wing members are adjustable and can be rotated about a fold line. The semi-rigid wing members can be separate and attachable to the foldable, semi-rigid sheet or can be an integral part, or of a permanent connection of the semi-rigid sheet. The semi-rigid wing members may be composed of any suitable material, examples of which are cardboard or plastic.
[0028] The semi-rigid wing members may be characterized by a substantially uniform height. Further, the semi-rigid wing members may be flexibly spread apart at an adequate wingspan determined by reference to a specific application-determined wingspan table according to uniform wingspan height, pipeline fitting size, pipeline system pressure, soil bearing strength, and the configuration of the of the pipeline fitting.
[0029] A system for forming a thrust block used to support a pipeline fitting would also be within the scope of the claimed invention. The system would essentially include a semi-rigid sheet having an aperture closely conforming to the outer shape of the pipeline fitting of a variety of pipeline fitting configurations; and semi-rigid wing members adapted for hinged folding for dimensional control of the thrust block surface area to be created by the molding form. The semi-rigid sheet and the semi-rigid wings in combination are further capable to define a thrust block having a selected wingspan based on the characteristics of the wing member uniform height, pipeline fitting size, pipeline fitting configuration, piping system pressure, and soil bearing strength.
[0030] Another embodiment of the present invention essentially is a device for forming a thrust block for use with an underground pipeline system. The device includes a form having an aperture. The aperture is shaped to surround a portion of a pipe fitting, and the form is suitable for molding at least a portion of the thrust block. In several embodiments, the device accommodates pipe fittings selected from the group consisting of tee fittings, 90° elbow fittings, 45° elbow fittings, 22.5° elbow fittings, 11.25° elbow fittings, and end fittings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present invention. The figures are not necessarily drawn to scale. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein.
[0032] [0032]FIG. 1 is an isometric view of a thrust block form in accordance with one embodiment of the present invention.
[0033] [0033]FIG. 2 shows a semi-rigid sheet configurable into a thrust block form with wings in accordance with one embodiment of the present invention.
[0034] [0034]FIG. 3 shows a semi-rigid sheet configurable into a thrust block form with attachable wing members in accordance with another embodiment of the present invention.
[0035] [0035]FIG. 4 is an isometric view of a configuration of a thrust block form with its aperture closely conforming to the outer shape of a pipeline fitting in accordance with one embodiment of the present invention.
[0036] [0036]FIGS. 5A, 5B, 5 C, and 5 D are top views of a thrust block form with wing members rotated about a hinged fold line adjusted to various wingspans as appropriate in accordance with one embodiment of the present invention.
[0037] [0037]FIGS. 6A, 6B, 6 C, 6 D, 6 E, and 6 F show uses of thrust block forms with various pipeline fitting configurations in accordance with embodiments of the present invention.
[0038] [0038]FIG. 7 is perspective view from the back of a configured thrust block form indicating a resultant substantially rectangular cross-sectional surface area that provides the functional surface area against the undisturbed earthen trench wall to resist thrust forces and to prevent pipeline fitting movement.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0039] The following examples are included to demonstrate embodiments of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventor to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention.
[0040] The present invention addresses and overcomes the lack of availability of existing forms or methods of the construction of forms for the purpose of molding thrust blocks, with a standardized, measurable, and inexpensive apparatus and system for the forming and construction of thrust blocks.
[0041] [0041]FIG. 1 is an isometric view of a thrust block form 100 . In the embodiment shown in FIG. 1, the thrust block form 100 comprises a semi-rigid sheet of material 105 that has been configured into a form 110 for molding a thrust block, with an aperture 115 adapted for accommodating a pipeline fitting. In some embodiments, the sheet of material 105 may be cardboard or other semi-rigid materials.
[0042] The semi-rigid sheet of material 105 may comprise one or more patterns of lines, pre-stressed fold lines or perforations to facilitate configuration into one or more forms.
[0043] The aperture 115 is adapted to conform to pipeline fittings of various configurations within a given nominal size. An appropriately sized aperture 115 will ideally be large enough to provide sufficient bearing surface area on the fitting, yet small enough to prevent concrete from contacting any portion of the bell gasket housing or the joint between the fitting and the pipeline. In some embodiments, the aperture 115 has a deformable lip to contact and conform to the pipeline fitting.
[0044] Now referring to FIG. 2, a thrust block form 200 in accordance with one embodiment of the present invention comprises a semi-rigid sheet of material 205 that is configurable into a molding form, including an aperture 115 , and further includes wing members 208 , defining a form for molding a thrust block.
[0045] In the preferred embodiment, the sheet of material 205 further includes a table 212 indicating the required wingspan width for adjusting the functional size (thrust resistant surface area) of the form after the form is placed on the pipeline fitting thus the implementation that facilitates constructing the form quickly and accurately.
[0046] The following TABLE 1 provides one example of a table 212 that would be used in the preferred embodiment with a thrust block form 200 suitable for use with 4″ pipeline fittings.
TABLE 1 Pressure 90° Bend Tee/DE 45° Bend 22 ½° Bend 1,000 lb/ft 2 Soil Bearing Capacity 100 psi 20.5″ 14.5″ 11.1″ 5.7″ 125 psi 25.6″ 18.2″ 13.9″ 7.1″ 150 psi *30.8″ 21.8″ 16.7″ 8.5″ 200 psi *41.0″ *29.0″ 22.2″ 11.4″ 250 psi *51.2″ *36.2″ *27.8″ 14.2″ 2,000 lb/ft 2 Soil Bearing Capacity 100 psi 10.3″ 7.3″ 5.6″ 2.9″ 125 psi 12.8″ 9.1″ 7.0″ 3.6″ 150 psi 15.4″ 10.9″ 8.4″ 4.3″ 200 psi 20.5″ 14.5″ 11.1″ 5.7″ 250 psi 25.6″ 18.2″ 13.9″ 7.1″ 3,000 lb/ft 2 Soil Bearing Capacity 100 psi 6.9″ 4.9″ 3.7″ 1.9″ 125 psi 8.6″ 6.1″ 4.7″ 2.4″ 150 psi 10.3″ 7.3″ 5.6″ 2.9″ 200 psi 13.7″ 9.7″ 7.4″ 3.8″ 250 psi 17.1″ 12.1″ 9.3″ 4.8″
[0047] The following TABLE 2 is a second example of a table 212 that would be used in the preferred embodiment with a thrust block form 200 suitable for use with 2″ pipeline fittings.
TABLE 2 Pressure 90° Bend Tee/DE 45° Bend 22 ½° Bend 1,000 lb/ft 2 Soil Bearing Capacity 100 psi 10.1″ 7.1″ 5.5″ 2.8″ 125 psi 12.6″ 8.9″ 6.8″ 3.5″ 150 psi 15.1″ 10.7″ 8.2″ 4.2″ 200 psi 20.1″ 14.2″ 10.9″ 5.6″ 250 psi 25.1″ 17.8″ 13.6″ 7.0″ 2,000 lb/ft 2 Soil Bearing Capacity 100 psi 5.1″ 3.6″ 2.8″ 1.4″ 125 psi 6.3″ 4.5″ 3.4″ 1.8″ 150 psi 7.6″ 5.4″ 4.1″ 2.1″ 200 psi 10.1″ 7.1″ 5.5″ 2.8″ 250 psi 12.6″ 8.9″ 6.8″ 3.5″ 3,000 lb/ft 2 Soil Bearing Capacity 100 psi 3.4″ 2.4″ 1.9″ 1.0″ 125 psi 4.2″ 3.0″ 2.3″ 1.2″ 150 psi 5.1″ 3.6″ 2.8″ 1.4″ 200 psi 6.7″ 4.8″ 3.7″ 1.9″ 250 psi 8.4″ 6.0″ 4.6″ 2.4″
[0048] Now referring to FIG. 3, an embodiment of the present invention is shown in which a thrust block form 300 comprises a sheet 301 that is configurable for defining a thrust block form, with two separate and attachable side wing members 306 , singularly or in combination with the side wing members 306 defining the trust block form 300 . Similar to the sheet of material 205 shown in FIG. 2, the sheet of material 305 may include information in the form of a table 315 , to facilitate construction in the field accurately and quickly. The information contained in the table is application specific to the nominal size of the fitting for which the thrust block form is designed.
[0049] Now referring to FIG. 4, an embodiment of the present invention is shown as it may be used to support a bend fitting 405 in a pipeline. In the embodiment shown the fitting 405 is a 90° bend fitting. However, the invention is not limited to use with any one fitting, but is adapted for use and usable on one of several fittings with a nominal fitting size.
[0050] [0050]FIGS. 5A, 5B, 5 C, and 5 D show a thrust block form 502 having hingedly connected wings 504 , 506 adjusted to various wingspans 508 , 510 , 512 , and 514 . Further, the combination of wingspan with the uniform vertical height of the wing members of the form creates a measurable and determined cross-sectional surface area defining the total thrust resistance surface area of the thrust block being formed.
[0051] Turning to FIGS. 6A, 6B, 6 C, 6 D, 6 E, and 6 F, the applications of various thrust block forms 602 , 606 , 610 , 614 , 618 , and 622 to various pipe fittings—tee fitting 604 , 90° fitting 608 , 45° fitting 612 , 22.5° fitting 616 , 11.25° fitting 620 , and end fitting 624 , respectively—are shown. The specific fittings shown, and their dimensions, have been selected merely by way of example, and not by way of limitation.
[0052] [0052]FIG. 7 shows an embodiment of the present invention wherein a folded thrust block form 701 , is shown with the ability to create a determinate and substantially rectangular force resistance area 704 as defined by the outer edge of the wing member 702 and the outer and opposite edge of wing member 703 .
[0053] In the preferred embodiment of the present invention, the wing members 702 and 703 are of substantially uniform height. The uniform height of wing members fixes or makes constant one of the dimensions defining the cross-sectional area of the thrust block being formed. The rotation of the wing members about the hinged fold line allows the 2 nd dimension of the substantially rectangular area to be set, adjusted, or determined by the distance between the outer and opposite edges of the wing members. The distance between the edges of the two outer and opposite edges of the wing members is denoted as the wingspan. With one dimension of the substantially rectangular thrust resistant cross-sectional surface area determined by the uniform height of the wing member, then the total cross-sectional area becomes directly proportional to the adjustable wingspan dimension. This dimensional relationship, as a result of the formation of a substantially rectangular cross-sectional area, eases creation of unique and specific adjustment tables 212 and 315 in the illustrated embodiments.
[0054] The present invention has been disclosed in connection with specific embodiments. However, it will be apparent to those skilled in the art that variations from the illustrated embodiments may be undertaken without departing from the spirit and scope of the present invention. For example, a sheet of material may have more than one aperture. This and other variations will be apparent to those skilled in the art in view of the above disclosure and are within the spirit and scope of the present invention. Further, the word “a” as used in this specification does not preclude the presence of a plurality of elements accomplishing the same function. The word “notched,” as used herein, includes the meaning of the word “varieted.”
[0055] All references cited herein are incorporated by reference to the maximum extent allowable by law. To the extent a reference may not be fully incorporated herein, it is incorporated by reference for background purposes and indicative of the knowledge of one of ordinary skill in the art.
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The present invention provides a thrust block form for use with underground pipelines and piping systems. An inexpensive, disposable or reusable sheet of material that includes lines, indentations, or perforations to facilitate field folding, and that may have wings, or connect to wings, is used to quickly and accurately determine and define a necessary shape and configuration of a thrust block for a selected fitting. A thrust block form is adapted to conform with all fittings of a selected size, and a table printed on the sheet of material provides quick reference for accuracy and time savings.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present application relates to safety pressure limiting features on cryogen vessels, particularly in respect of cryogen vessels containing superconducting magnets of magnetic resonance imaging (MRI) systems. In particular, it relates to the advantageous arrangement of components of an auxiliary vent path, provided to limit pressure within the cryogen vessel in case of a quench of the superconducting magnet.
[0003] 2. Description of the Prior Art
[0004] FIG. 1 shows a conventional arrangement of a cooled superconducting magnet 10 within cryogen vessel 12 , itself retained within an outer vacuum chamber (OVC) 14 . One or more thermal radiation shields 16 are provided in the vacuum space between the cryogen vessel 12 and the outer vacuum chamber 14 . In some known arrangements, a refrigerator 17 is mounted in a refrigerator sock 15 located in a turret 18 provided for the purpose, towards the side of the cryostat. Alternatively, a refrigerator may be located within an access turret 19 , which retains access neck (vent tube) 20 mounted at the top of the cryostat. The refrigerator provides active refrigeration to cool cryogen gas, typically helium, within the cryogen vessel 12 , in some arrangements by recondensing it into a liquid 22 . The refrigerator may also serve to cool the radiation shield 16 . As illustrated in FIG. 1 , the refrigerator 17 may be a two-stage refrigerator. A first cooling stage is thermally linked to the radiation shield 16 , and provides cooling to a first temperature, typically in the region of 80-100K. A second cooling stage provides cooling of the cryogen gas to a much lower temperature, typically in the region of 4-10K.
[0005] A negative electrical connection 21 a is usually provided to the magnet 10 through the body of the cryostat. A positive electrical connection 21 is usually provided by a conductor passing through the vent tube 20 .
[0006] For fixed current lead (FCL) designs, a separate vent path (auxiliary vent) (not shown in FIG. 1 ) is provided as a fail-safe vent in case of blockage of the vent tube 20 . It is this auxiliary vent path which is the subject of the present invention.
[0007] FIG. 2 shows an example of a conventional over-pressure limiting protection arrangement 30 , designed to vent cryogen gas from the cryogen vessel in case of over-pressure, such as could occur following a quench of the magnet.
[0008] A superconducting magnet 10 is contained within a cryogen vessel 12 as discussed with reference to FIG. 1 . A turret outer assembly 24 encloses upper extremities of access neck (vent tube) 20 and positive current lead 21 , and provides a normal exit path 26 for cryogen gas from cryogen vessel 12 . Turret outer assembly 24 is joined to the cryogen vessel in a leak-tight manner and defines an interior volume which is separated from atmosphere by a protective valve and/or burst disc, and forms part of normal exit path 26 . The protective valve and/or burst disc in the illustrated example is quench valve 32 .
[0009] In the event of a quench, the cryogen vessel 12 is vented to atmosphere via the vent tube 20 in the access turret 19 through the interior volume of the turret outer assembly 24 and quench valve 32 . Quench valve 32 includes a valve plate 34 which is held against valve seat 36 by a spring arrangement 38 . Cryogen egress tube 40 leads exit path 26 to atmosphere, or to a cryogen recuperation facility, essentially at atmospheric temperature. In case of over-pressure within cryogen vessel 12 , a corresponding pressure of cryogen gas within the turret outer assembly 24 acting on the inner side 34 a of the valve plate 34 will exceed the pressure acting on the outer side 34 b of the valve plate sufficiently to overcome the force of the spring arrangement 38 and open the valve 32 . Cryogen gases will escape, maintaining the pressure within the cryogen vessel at an acceptable level. Once the pressure in the cryogen vessel and the interior volume of the turret outer assembly 24 drops below the pressure needed to keep the quench valve 32 open, spring 38 will press the valve plate 34 back into contact with valve seat 36 .
[0010] Part of the valve plate 34 may be formed by a burst disc, not visible in the drawing as it lies in the plane of the valve plate 34 . In case the differential pressure across the valve plate becomes much higher than the pressure at which the quench valve 32 should open, for example if the quench valve 32 sticks, or the pressure increase within the cryogen vessel is extremely rapid or severe, the burst disc will rupture and cryogen gas will then escape through a hole left by the burst disc and out of the cryogen vessel 12 through the interior volume of the turret outer assembly 24 and egress tube 40 . This burst disc is typically a declared regulatory pressure relief safety device, provided to rupture in the event of quench valve failure.
[0011] In addition to the declared safety device, an auxiliary vent path 42 is provided, through a tubular positive current lead 21 to atmosphere via an external room-temperature tube 44 fitted with its own auxiliary burst disc 46 . Auxiliary vent path 42 does not pass through the interior volume of the turret outer assembly 24 . The auxiliary burst disc 46 is designed to rupture when a differential pressure across it meets a certain value, in excess of the differential pressure at which quench valve 32 is designed to open, and in excess of the differential pressure at which the bust disc within valve plate 34 is designed rupture.
[0012] It is known that air ingress into the access neck 20 may cause ice to form in region 48 , between the inner wall of the access neck 20 and the positive current lead 21 . If sufficient ice forms in this region, it may form a constriction, and cryogen gas may not be able to freely escape in case of a quench. A differential pressure may exist across the blockage, reducing the differential pressure across the quench valve 32 .
[0013] On the other hand, the positive current lead 21 passes into the cryogen vessel more deeply than the ice-forming region 48 , to the level of temperatures usually so cold that any air ingress into the access neck 20 freezes onto the access neck in region 48 and before it can reach the lower end of the positive current lead 21 . The interior of the tubular positive current lead 21 may therefore be assumed to be free of ice. As there is no blockage in the positive current lead, the full differential pressure between the interior of the cryogen vessel 12 and atmospheric pressure in the egress tube 40 will apply across the auxiliary burst disc 46 . Burst disc 46 is designed to rupture at a pressure high enough that it can only be reached if the quench valve 32 and its burst disc have failed to protect the cryogen vessel as designed.
[0014] Typically, quench valve 32 is designed to open in response to a 0.5 BAR (50 kPa) differential pressure between the high pressure side 34 a exposed to the interior volume of the turret outer assembly 24 and the low pressure side 34 b exposed to the interior of the egress tube 40 . The burst disc within the quench valve is typically designed to rupture in response to a differential pressure of 1.4 BAR (140 kPa), and the auxiliary burst disc 46 is typically designed to rupture in response to a differential pressure of 1.8 BAR (180 kPa). These values are chosen to protect the cryogen vessel in all circumstances, but are sufficiently separated that the quench valve 32 will open without damage to the burst disc within the quench valve unless the quench valve is stuck, and that the auxiliary burst disc 46 will only rupture in response to a cryogen vessel pressure so high that it is clear that neither the quench valve 32 nor the burst disc within the quench valve are going to open.
[0015] This arrangement has certain drawbacks, which the present invention seeks to alleviate.
[0016] In present arrangements such as shown in FIG. 2 , the auxiliary burst disc 46 is permanently subjected to the full differential pressure between the interior volume of the turret outer assembly 24 and the cryogen vessel on one side and the egress path 40 , which is at approximately atmospheric pressure, on the other side. This differential pressure may approach the pressure at which the auxiliary burst disc 46 is designed to rupture.
[0017] During a quench event which is vented through the auxiliary burst disc 46 , the pressure within the cryogen vessel may approach the maximum allowable working pressure of the cryogen vessel, due to the constriction of escaping gas in the “room-temperature” tube 44 and the rapid expansion of this cryogen gas due to heating as it passes through the “room temperature” tube 44 . It would be preferable from this point of view to provide a room temperature tube 44 of increased cross-section, but this would have the undesired effect of increasing the height of the overall system.
[0018] In the event of rupture of the auxiliary burst disc 46 , air can be drawn back into the auxiliary vent path 42 once the over-pressure within the cryogen vessel has ceased. This can cause a buildup of ice within the tubular positive current lead 21 which is difficult to detect or remove.
[0019] A further disadvantage is the cost of the external room-temperature pipe work 44 and seals required to interface the auxiliary vent path 42 to the remainder of the equipment. The external pipe work 44 adds to overall system height, which causes integration problems in siting the cryostat. Any external joints, seals, welds etc. all have the potential to cause leaks into the vent path during normal service, and so their number should preferably be reduced.
SUMMARY OF THE INVENTION
[0020] The present invention addresses these, and further, problems by relocating the auxiliary burst disc to the tubular positive current lead 21 , preferably to the top of the tubular positive current lead 21 within the turret outer assembly 24 . In the event of the normal exit path 26 becoming blocked or restricted, cryogen gas escapes via the tubular positive current lead to atmosphere via the turret outer assembly and through the quench valve or burst disc.
[0021] UK patent GB2472589 proposes a single vent path in a similar application.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 shows a conventional cryostat arrangement housing a superconducting magnet.
[0023] FIG. 2 shows a conventional over-pressure limiting arrangement.
[0024] FIG. 3 shows an over-pressure limiting arrangement according to an embodiment of the present invention;
[0025] FIG. 4 shows a step in a servicing method for the over-pressure protection arrangement of FIG. 3 .
[0026] FIGS. 5A and 5B illustrate a valve which may be used in certain embodiments of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] As shown in FIG. 3 , an over-pressure limiting arrangement according to an embodiment of the present invention comprises an auxiliary burst disc 50 placed at or near the upper extremity of the tubular positive current lead 21 , within the turret outer assembly 24 . The inner surface 50 a of the auxiliary burst disc 50 is exposed to the interior of the tubular positive current lead 21 , and thence to the interior of the cryogen vessel 12 . The outer surface 50 b of the auxiliary burst disc 50 is exposed to the interior of the turret outer assembly 24 . The auxiliary burst disc may be mounted onto a carrier 51 which is mounted by pillars 52 onto a removable cover plate 54 , which may be fastened by bolts 56 and sealed by o-ring 58 to the turret outer assembly 24 .
[0028] As for the conventional arrangement of FIG. 2 , the normal exit path 26 in the arrangement of FIG. 3 is through access neck 20 , turret outer assembly 24 and through quench valve 32 . However, according to the present invention, the auxiliary vent path 42 is also through the turret outer assembly 24 and through quench valve 32 . Escaping cryogen gas may flow through auxiliary burst disc 50 and between pillars 52 which surround the auxiliary burst disc 50 and mount the carrier 51 onto a removable cover plate 54 , as shown.
[0029] Provided that normal exit path 26 is not blocked, over-pressure within the cryogen vessel will cause increased differential pressure between inner 34 a and outer 34 b sides of the valve element 34 of quench valve 32 . Once that differential pressure becomes sufficient to overcome the force applied by the spring 38 , the quench valve 32 will open and release cryogen gas from the interior volume of the turret outer assembly 24 into the egress tube 40 , to reduce the pressure in the cryogen vessel. Once a sufficient amount of cryogen gas has escaped to reduce the pressure within the cryogen vessel to a normal level, the force applied by spring 38 is sufficient to close the quench valve 32 .
[0030] In the event of the normal exit path 26 becoming blocked or restricted, typically by a build-up of ice in region 48 between the inner wall of access neck 20 and tubular positive current lead 21 , pressure within the cryogen vessel will build up until the differential pressure between inner 50 a and outer 50 b sides of auxiliary burst disc 50 is sufficient to cause the auxiliary burst disc to rupture. Cryogen gas then escapes through the tubular positive current lead 21 to atmosphere via the turret outer assembly 24 and through the quench valve 32 . Unlike with the conventional auxiliary burst disc arrangement of FIG. 2 , the auxiliary vent path 42 closes once a sufficient amount of cryogen gas has escaped to reduce the pressure within the cryogen vessel to a normal level, and the force applied by spring 38 is sufficient to close the quench valve 32 .
[0031] In such an arrangement of the present invention, the auxiliary burst disc 50 may be designed to rupture at a relatively low differential pressure. This will occur if sufficient pressure differential exists between the cryogen vessel 12 and the turret outer assembly 24 , which will only occur if some blockage is present in the normal egress path 26 . The auxiliary burst disc may be designed to open at a differential pressure of 0.5 bar (50 kPa), regardless of whether the quench valve 32 is open or closed. Quench valve 32 may be designed to open at a typical differential pressure of 0.5 BAR (50 kPa), so the auxiliary burst disc 50 should rupture in response to a 1 BAR (100 kPa) pressure difference between the cryogen vessel 12 and the egress path 40 , assuming a total blockage of normal exit path 26 in the region 48 . Due to the constrictions in the auxiliary vent path 42 , the pressure in the cryogen vessel may rise during venting, but in this example is unlikely to exceed 1.4 BAR (1400 kPa) above the pressure in the egress tube 40 , which is typically at atmospheric pressure.
[0032] In an alternative arrangement, the auxiliary burst disc 50 may be replaced by a valve. There are certain advantages that may be achieved in this way. The valve may have a lower opening pressure than the burst disc, and may be arranged to open during any quench, whether the gap between the access neck and the positive current lead 21 is clear or not, so as to share cryogen flow between normal exit path 26 and auxiliary vent path 42 .
[0033] The valve should be arranged to re-seal after a quench, and would not require replacing each time it opened, which is the case for a burst disc. Some leakage of the valve may be acceptable, as there would be no leakage of cryogen to egress tube 40 under normal conditions, as quench valve 32 would remain closed. In its simplest form, a spring-loaded flap valve may be used. It may be preferred to include a burst disc within the valve, similar to the arrangement used with the quench valve 32 , to ensure opening of the auxiliary vent path 42 even in case of the valve sticking closed. Removable cover plate 54 should still be provided, to allow for inspection and replacement of the valve.
[0034] The present invention provides auxiliary burst disc 50 or valve closing auxiliary vent path 42 in normal operation, and which opens into the turret outer assembly 24 , upstream of the quench valve 32 , when required.
[0035] The auxiliary quench path is accordingly protected by the declared regulatory pressure relief safety device, the burst disc in quench valve 32 , in the same way as the normal egress path 26 .
[0036] The differential pressure across the auxiliary burst disc 50 is greatly reduced, as compared to the differential pressure experienced by auxiliary burst disc 46 of conventional arrangements such as illustrated in FIG. 2 , as the differential pressure across the auxiliary burst disc 50 is now the pressure differential between the cryogen vessel 12 and the interior of the turret outer assembly 24 , rather than the pressure differential between the cryogen vessel 12 and atmosphere. This pressure differential is approximately halved, which means the rupture pressure of the burst disc can be correspondingly reduced. The pressure within the turret outer assembly 24 at the point of bursting of the auxiliary burst disc 50 may be predicted by conventional methods of Computational Fluid Dynamics, or may be measured by experimentation.
[0037] The present invention enables reliable operation of the auxiliary burst disc 50 and the auxiliary vent path 42 at a lower cryogen vessel pressure in the event of a quench through the auxiliary vent. In a normal steady-state situation, the differential pressure across the auxiliary burst disc 50 is zero, as pressure within the tubular positive current lead 21 will equalize with pressure within the turret outer assembly 24 by flow of cryogen gas through the normal exit path 26 . This makes unwanted rupture of the auxiliary burst disc very unlikely. Auxiliary burst disc 50 will rupture only if a pressure differential exists between the cryogen vessel 12 and the volume enclosed by the turret outer assembly 24 . This in turn will only occur if the normal exit path 26 is substantially blocked in the access turret 20 , and either the pressure within the cryogen vessel has increased more rapidly than cryogen has been able to flow through normal exit path 26 to equalize with the pressure in the turret; or the quench valve 32 has at least partially opened, reducing the pressure within the turret outer assembly 24 . Ice formation in region 48 may form a constriction, but is unlikely to completely block the normal exit path 26 . In case of over-pressure within the cryogen vessel, some gas will flow through the constriction at 48 to partially open the quench valve 32 . This partial opening of the quench valve will increase the differential pressure across the auxiliary burst disc 50 and cause it to rupture. Even with cryogen gas flowing through the normal exit path 26 and quench valve 32 , the differential pressure across the auxiliary burst disc 50 will increase as the normal exit flow path becomes restricted due to ice build-up, typically in the region 48 .
[0038] The auxiliary burst disc 50 is concealed within the turret outer assembly 24 , and so is very unlikely to be mechanically damaged. In the conventional arrangement of FIG. 2 , the outer casing of the auxiliary burst disc 46 is located at the very top of the cryostat, in a position which is exposed to possible mechanical damage during siting, or service operations.
[0039] The auxiliary burst disc 50 is in an air-free atmosphere, within the turret outer assembly 24 , during normal service. The chances of any air ingress into the vent path 42 within the tubular positive current lead 19 are extremely low.
[0040] After venting of cryogen gas through a ruptured auxiliary burst disc 50 , the chances of air ingress into the vent path 42 within the tubular positive current lead 19 are very low as the quench valve 32 re-seals the turret outer assembly 24 from atmosphere. It would only be possible for air ingress to reach beyond the ruptured auxiliary burst disc 50 if burst disc of the quench valve 32 is ruptured. Under these circumstances the air ingress would be shared between the normal 26 and the auxiliary 42 vent paths.
[0041] The cost of providing, fitting and maintaining the conventional external room-temperature pipework 44 , with its seals etc. would be saved.
[0042] The height and installation complexity of the cryostat is reduced with the arrangement of the present invention.
[0043] In the case of a quench causing venting of cryogen gas through the auxiliary burst disc 46 of the conventional arrangement of FIG. 2 , a significant proportion of the pressure drop between the cryogen vessel 12 and the egress tube 40 is in the constrictive room-temperature pipework 44 , whose cross-section tends to be minimized to reduce the overall height of the system. In the arrangement of the present invention, the constrictive room-temperature pipework 44 is functionally replaced by the much larger cross-section of the turret outer assembly 24 , quench pipe 60 and quench valve 32 or its burst disc.
[0044] The turret outer assembly 24 and quench valve 32 operate at room temperature so consequently remain ice free. There is no risk of the normal exit path 26 and the auxiliary vent path 42 from becoming obstructed due to a build-up of ice in the turret outer assembly 24 and quench valve 32 . Even when cold during ramping and filling operations, no ice builds up in these regions.
[0045] Advantageously, the auxiliary burst disc 50 may be attached by pillars 52 to a plate 54 sealing a port in the service entry plate 62 , part of the structure of the turret outer assembly 24 . As illustrated in FIG. 4 , such arrangement enables the auxiliary burst disc 50 to be removed easily for replacement, or to allow other service operations to be carried out.
[0046] As is conventional in itself, the auxiliary burst disc 50 could be fitted with electrical contacts to enable an alarm signal to be sent to the magnet supervisory system in the event of rupture of the auxiliary burst disc. This has the benefit of allowing remote diagnosis of disc rupture, enabling appropriate service action to be planned. In an example embodiment, the disc rupture sensing contacts could be wired in series with a refrigerator pressure sensor input, which may be arranged to switch off the refrigerator 17 in the event of auxiliary burst disc rupture. This would provide for a remote indication of auxiliary burst disc rupture without having to make any change to the magnet supervisory system. In addition, such an arrangement would reduce the chance of air ingress by turning off the refrigerator immediately and so allowing the cryogen vessel pressure to build up until a safety valve opens, which may be quench valve 32 . Cryogen gas will flow out of the cryogen vessel at a rate determined by the thermal influx into the cryogen vessel, significantly reducing air ingress.
[0047] In an alternative embodiment, a sight glass could be fitted such that a visual inspection may be performed following a quench to determine whether the auxiliary burst disc 50 needs to be replaced. This is particularly simple in the case of arrangements such as shown in FIGS. 3-4 , as a sight glass may be positioned in the cover plate 54 , directly above the auxiliary burst disc 50 .
[0048] During ramping of current into the magnet 10 , liquid cryogen 22 is boiled off, and cold escaping cryogen gas cools the auxiliary burst disc 50 . Similarly, the auxiliary burst disc 50 will be cooled when the cryogen vessel 12 is filled, or topped-up, with liquid cryogen 22 . Due to the material properties of a typical burst disc, this cooling will raise the burst pressure of the burst disc by approximately 10-20%. In preferred embodiments of the present invention, the burst pressure of the auxiliary burst disc 50 may be substantially less than the burst pressure of the auxiliary burst disc 46 of the conventional arrangement, as explained above, and so the increase in burst pressure on cooling is proportionately lower. The position of the auxiliary burst disc 50 in the arrangement of the present invention also reduces the significance of the increase in burst pressure. Such temperature-dependent variation in burst pressure of burst discs is well understood among those skilled in the art, such variation may be compensated for during manufacture. The use of INCONEL® austenitic nickel-chromium-based superalloys for the disc material also reduces the effect by up to 50% as compared to other materials commonly used for burst discs, for example stainless steel.
[0049] As illustrated in FIG. 3 , but more clearly visible in FIG. 4 , a tube 64 could be bonded to the auxiliary burst disc 50 to prevent air ingress into the vent path through any gap between the auxiliary burst disc and the tubular positive current lead 21 . When installed, the tube 64 passes inside the tubular positive current lead 21 to a depth beyond the expected depth of freezing of air components, illustrated by region 48 in FIG. 3 . As illustrated, this may conveniently be achieved by bonding a tube 64 of fiberglass-reinforced plastic (GRP) onto carrier 51 which also carries the auxiliary burst disc 50 . Alternatively, the burst disc carrier 51 could be sealed to the top of the tubular positive current lead. However, in any normal operational situation, the concentration of air in the turret outer assembly 24 would be already at a very low level, so the risk of significant air influx through a small leak may be considered minimal.
[0050] FIG. 4 shows the auxiliary burst disc being removed for replacement. As shown, it is a relatively simple matter to remove bolts 56 and withdraw cover plate 54 , bringing auxiliary burst disc 50 on its carrier 51 with it. If necessary, the burst disc 50 may be replaced, but more conveniently, the burst disc carrier 51 may be replaced, carrying a new burst disc. Any tube 64 attached to the burst disc carrier 51 may be removed and attached to the replacement burst disc carrier 51 . It may be preferred to simply replace the whole assembly of burst disc 50 , burst disc carrier 51 , pillars 52 , cover plate 54 and any tube 64 when a service or replacement of burst disc is required.
[0051] In an alternative series of embodiments, as illustrated in FIGS. 5A and 5B , the auxiliary burst disc 50 is replaced by a valve 68 attached to the upper end of the tubular positive current lead 21 . Such valve may be of similar construction to the quench valve described, or may be any known type of safety valve suitable for carrying the desired flow rate of escaping cryogen. In FIG. 5A , a suitable spring-loaded flap valve 68 is shown closed, in cross-section, mounted at an upper extremity of the tubular positive current lead 21 . An inner surface 72 a of the valve is exposed to the interior of the tubular structure, and an outer surface 72 b of the valve is exposed to the interior volume of the turret outer assembly ( 24 ).
[0052] FIG. 5B shows the same valve 68 open. The spring-loaded flap valve 68 includes a valve seat 70 mounted atop the tubular positive current lead 21 . A valve flap 72 closes a through hole 73 in the valve seat. The valve flap is typically pivoted at a pivot 74 , and is urged into its closed position by a coil spring 76 . Such flap valves are common mechanical arrangements, but the materials chosen for the flap valve in the present invention must be suitable for operation at cryogenic temperatures. It may be preferred to mount such as valve atop a tube 64 such as illustrated in FIG. 4 to enable easy removal and replacement of the valve. However, by its nature, the valve 68 should not need to be replaced at every activation, and mounting direct to the tubular positive current lead 21 as shown in FIGS. 5A , 5 B may be found sufficient.
[0053] Similar to the arrangement shown in FIGS. 3 and 4 , the valve 68 may be mounted onto a carrier 51 which is itself mounted by pillars 52 onto a removable cover plate 54 .
[0054] Types of valves other than the described flap valve may be used, as appropriate. In some arrangements, the valve may be located within the tubular positive current lead structure 21 .
[0055] As such a valve would be situated in a cryogen-rich atmosphere within the turret outer assembly, the amount of air that could leak into the vent path may be regarded as insignificant. Also, this valve would preferably be self-closing, removing the need for inspection and replacement which is necessary where auxiliary burst discs 50 are used.
[0056] While the present invention has been described with reference to a limited number of specific embodiments, numerous variations will be apparent to those skilled in the art, within the scope of the appended claims. For example, the auxiliary burst disc 50 , or a valve performing its function, need not be positioned at the top of the positive current lead 21 , but may be positioned at any convenient position along the auxiliary vent path 42 between the lower end of the positive current lead 21 and the quench valve 32 , such as inside the positive current lead 21 . Although the present invention has described feature 21 as a “positive” current lead, this term is used in a descriptive, not limiting, manner reflecting present conventional electrical arrangements. The present invention may equally be applied to situations in which the magnet 10 is connected to a positive supply terminal through the material of the cryogen vessel, while a negative current lead, similar to feature 21 shown in the drawings, may provide connection between the magnet and a negative supply terminal. Furthermore, the present invention may employ a tubular structure similar to that illustrated at 21 in the drawings but which is not used as a current lead at all.
[0057] Quench valve 32 may be replaced by any suitable pressure limiting device, for example a simple burst disc.
[0058] Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted heron all changes and modifications as reasonably and properly come within the scope of their contribution to the art.
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An over-pressure limiting arrangement for a cryogen vessel includes an access neck providing access into the cryogen vessel, a tubular structure extending through the access neck, a turret outer assembly joined leak-tight to the cryogen vessel and defining an interior volume that is separated from the atmosphere by a protective valve or burst disc, enclosing an upper extremity of the access neck and the tubular structure. An egress path defines a route for cryogen gas to escape from the turret outer assembly, and a pressure-responsive quench valve seals the egress path and opens when a differential pressure between the interior of the turret outer assembly and the interior of the egress path exceeds a predetermined value. An auxiliary burst disc, or a valve, is attached to the tubular structure within the turret outer assembly, with an inner surface thereof exposed to the interior of the tubular structure and an outer surface thereof exposed to the interior of the turret outer assembly.
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FIELD OF THE INVENTION
The invention relates to the field of controllers for electrical devices, and more particularly to controllers for outdoor lighting systems.
BACKGROUND OF THE INVENTION
There are many uses for outdoor lighting systems. Many people find it desirable to have outdoor lights around their house. These lights add aesthetics to the house, provide an element of security by illuminating dark areas, and often increase the value of house and property. Parks and other public areas also benefit from the use of outdoor lights.
One limitation on the use of outdoor lights, however, is a mechanism for turning them on and off. It is usually not desirable to have the lights stay on all night, as this results in increased power usage and attendant costs.
Previous types of outdoor lighting controllers utilized a photocell to turn the lights on and off. As evening approached, the light falling on the photocell decreased. When the photocell sensed a certain level of dimness, the lights were turned on. The lights remained on until the photocell sensed that the amount of light falling on the photocell had reached a certain brightness. This type of controller had the limitations of keeping the lights on all night and not allowing the user to turn the lights on at any given time. The present invention overcomes these limitations by allowing the user to turn the lights on at any desired time and specify the amount of the time that the lights will remain lit.
SUMMARY OF THE INVENTION
The present invention comprises a controller for outdoor lighting systems. The controller allows the lights to be turned on and off at predetermined times that are designated by a user. The user turns the lights on and selects how many hours the lights are to remain lit. After the selected number of hours, the lights automatically turn off. The turn-on/turn-off sequence repeats every 24 hours unless the controller is reprogrammed. The controller monitors accurate timing by counting pulses in standard 120 volt, 60 Hertz, AC. A manual override is provided that does not interfere with the programmed times.
The controller of the present invention overcomes problems that are present in prior outdoor lighting systems. The automatic turn-off feature eliminates the need for the user to manually operate the lights. Because the controller's programmed sequence repeats every 24 hours, the user can set the controller once and the lights will automatically turn on at the selected time each day, and then automatically turn off after they have been lit the desired amount of time. The present invention also overcomes the problems of prior photocell type controllers which keep lights turned on all night. With the present invention, the user can program the lights to turn on at dusk, and remain on for only a few hours, as opposed to staying on until dawn. For example, a user may wish to turn the lights on at 8:00 p.m. and have them remain lit for 2 hours. This results in reduced power consumption and less cost to the user.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a functional block diagram of the present invention.
FIG. 2 is an electronic schematic of the preferred embodiment of present invention.
FIG. 3 is a block diagram showing the relationship between the present invention and other elements of an outdoor lighting system.
DETAILED DESCRIPTION OF THE INVENTION
An electrical controller for the control of outdoor lighting systems is described. Throughout the description the same numbers are used to designate the same elements of the invention.
Referring first to FIG. 1, a functional block diagram at the present invention is illustrated. The main elements of the controller are the pulse generator 23, the programmable divider circuit 33, the shift register 35 and the output latch 60. Power is supplied to the controller through the connector 10 from the power cord 9. The pulse generator 23 changes ordinary household current (120 volts AC) into a square wave pulse train. These pulses are then counted by the programmable divider circuit 33 which, in the preferred embodiment, generates an output pulse once every hour.
The shift register 35 contains a number of bits arranged in a serial manner. The preferred embodiment utilizes 24 bits--one for each hour of the day--but a different number can be used. The value of the bits in the shift register 35 are either 0 or 1. When the shift register 35 receives an output pulse from the programmable divider circuit 33, the contents of the shift register are shifted one position to the left. The contents of the most significant, or leftmost, bit moves to the least significant, or rightmost, position.
The output latch 60 monitors the most significant bit location. When the contents of this location change from a 0 to a 1 the output latch 60 generates a signal that turns the lights on. When the contents of the most significant bit changes from 1 to 0 the output latch turns off the lights. A manual override unit 59 is connected to the output latch. The manual override allows the lights to be turned on and off without affecting the timing circuits.
The user interface 24 performs two main functions. First it turns the lights on and initiates the timing sequence by resetting the programmable divider circuit 33 and the shift register 35. Second, it sets the value of at least one of the bits contained in the shift register to a value of 1. In the preferred embodiment the user interface 24 sets the most significant bit and up to seven additional bits to a value of 1, and the remaining bits to a value of 0. The bits set to a value of 1 are all adjacent to each other. Thus, the preferred embodiment allows the user to program the controller to keep the lights on for a total of seven hours.
The present invention is only one element of an outdoor lighting system. FIG. 3 shows a typical system incorporating the present controller 1. The system illustrated also has a power module 2 and the lights themselves 3. As shown, the controller does not actually drive the lights, but drives the power supply. It is to be understood that when the present description states that the controller "turns on" or "turns off" the lights 3, it may either do so directly or send a signal to the power supply to turn the lights on or off.
A more detailed description at the invention will now be provided with reference to FIG. 2. Power enters the controller through the power cord 9 and connector 10. In the preferred embodiment the 120 volt AC power is applied across connector pins 10a and 10f, with ground being connected to connector pin 10F. Resistor 11 and diode 12 are used to half-wave rectify the AC signal and present a low voltage direct current signal to capacitor means 13 and zener diode 14. The voltage level at the anode of diode 12 changes from a low value to a high value as the half-wave rectified AC signal rises. In the preferred embodiment, the input frequency of the AC signal is 60 Hertz and the anode of the diode 12 changes to a high state approximately every 16.67 milliseconds. The change in state at the anode of diode 12 is sensed by the input of logic gate 17. In the preferred embodiment logic gate 17 is an OR gate. Resistor 18 and capacitor 19 provide filtering and hysteresis such that a clean filtered square wave signal is present at the output 20 of the OR gate 17.
Integrated circuits 25-29 are counters which form a programmable divider circuit. The input 21 to the programmable divider circuit is connected to the output of the OR gate 17. The programmable divider circuit counts the number of pulses output from the OR gate, and, after a predetermined number of pulses, outputs a signal at the output 22 of the programmable divider circuit. In the preferred embodiment, the programmable divider circuit counts 216,000 input pulses before generating an output pulse. Since the preferred embodiment inputs a pulse to the programmable divider circuit approximately each 16.67 milliseconds, the programmable divider circuit generates an output pulse once every hour. It will be appreciated by those skilled in the art that different numbers of input pulses may be counted in order to generate output pulses at different time intervals.
The output 22 of the programmable divider circuit is connected to a serial shift register, which in the preferred embodiment, is comprised of integrated circuits 30-32. Each of the integrated circuits 30-32 is an 8 bit parallel load serial shift register and in the preferred embodiment the registers connected serially. Thus, a single 24 bit serial shift register is created. For the purposes of this disclosure, the bits in the shift register will be described as being arranged in a horizontal, left to right relationship with the most significant bit being the leftmost bit.
Whenever an output pulse appears at the output 22 of the programmable divider circuit 33, the bits in the shift register change position. Each bit moves one position to the left with the leftmost bit rotating to the rightmost position. Thus, in the preferred embodiment, the bits change position once each hour. One bit location is monitored as the output 36 of the serial shift register 35. In the preferred embodiment, the most-significant bit is monitored.
The signal at output 36 of the shift register passes through signal line 62 to the output latch 60. The output latch acts as an edge triggering device. Resistor 66 provides a feedback signal to OR gate 38. Because of the feedback, the output of OR gate 38 will only change state when signal line 62 changes. When the output of the shift register 35 changes from a low value to a high value, the output of OR gate 38 latches at a high value. Conversely, when the output of the shift register 35 changes from a high value to a low value, the output of OR gate 38 latches at a low value. The output of OR gate 38 is fed into OR gate 39. The output of OR gate 39 is connected to the connector 10 at the connector pin 10d. When the output of the OR gate 39 is high, the lights are on. When the output is low the lights are off. When the programmed number of hours have passed, the output of the shift register will change to a low value thus turning the lights off.
The operation of the user interface 24 will now be described. The user interface consists of switches 34 and 55 and AND gate 54. In the preferred embodiment, switch 55 is normally open and is of the momentary contact type. The inputs to AND gate 54 are pulled low through resister 53 when switch 55 is open. Thus, the output of AND gate 54 is also held low. When Switch 55 is closed, the inputs of AND gate 54 are high and the output of AND gate 54 is consequently pulled high. This signal travels over reset line 61 to integrated circuits 25-29 which comprise the programmable divider circuit and integrated circuits 30-32 which comprise the shift register. A high signal level on the reset line causes the dividers in the programmable divider circuit to be reset to zero. This initiates the timing sequence. Also, each of the 24 bits in the shift register is loaded with a value of 0 or 1 as will be more fully described below. Closing of switch 55 also causes a high signal to appear at the output 36 of the shift register 35, which, as described above, causes output latch 60 to generate a signal which turns the lights on.
The manner in which the bits are loaded into the shift register will now be described. In the preferred embodiment, the inputs 31a--31h and 32a--32h to the 8-bit shift registers on integrated circuits 31 and 32 are tied to ground through lines 63 and 64, respectively. Also, the input 30h to bit number 8 of the 8-bit shift register on integrated circuit 30 is tied to ground through line 65. This causes the least significant 17 bits of the 2 bits in the shift register 35 to be set to zero when switch 55 is closed. In the preferred embodiment, these comprise bits 8-24. The preferred embodiment thus allows bits 1-7 of the 24 bit register to be programmed with either a 0 or 1 depending on how long the user desires the lights to remain turned on.
Bits 1-7 are programmed with the use of switch 34 and diodes 47-52. In the preferred embodiment, switch 34 is a slide switch with seven selectable positions. When the switch 34 is in position 34i all of the inputs 30a-30g are tied to ground through resisters 40-46. However, when switch 34 is in any other position, some of the inputs are connected to a voltage on line 63. For example, when switch 34 is in position 34c, input 30c is connected directly to voltage line 63. Also, current flows through diodes 47 and 48 and resistors 40 and 41, thereby causing high signals to appear at inputs 30a and 30b as well as 30c. Inputs 30d-30g are isolated by means of diode 49, which is reverse-biased, and remain tied to ground through resistors 43-46. Therefore, when switch 34 is in position 34c and switch 55 is closed thereby enabling shift register to be loaded, a value of 1 is loaded into the three most significant bits of the shift register and the remaining bits are loaded with a value of zero.
Every hour, a pulse from the programmable divider circuit 33 will shift the bits in the shift register one bit to the left. Thus in the foregoing example, after three hours, the most significant bit in the shift register 33 will change to a low value. As described above, this will cause the output latch to generate a signal to turn the lights out. Since there are 24 total bits in the shift register 33, the bits will return to their original positions in 24 hours, or one day, after the lights are initially turned on. At that time the most significant bit will go high and the lights will turn on. A specific illustration of the use of the present invention will be given in the following example. A user may wish to have the lights turn at 8:00 p.m. and stay lit for 3 hours. To do this, the user would simply set switch 34 in position 34c and wait until 8:00 p.m. At that time, the user would press Switch 55, thus turning on the lights. The lights would remain on for 3 hours. The next day, the lights would again turn on at 8:00 p.m. and stay lit for 3 hours. This sequence would repeat until the controller was reprogrammed.
A manual override is provided by switches 56 and 57. Switch 56 presents a high value to the input of the OR gate 38. Switch 57 presents a low value to the input of the OR gate 38. As described above, the output of OR gate 38 will latch in a particular state because of the feedback through resistor 66. Thus, when the lights are turned on or off by switches 56 or 57, respectively, they will stay in that condition until signal line 62 changes state or a switch is activated. These switches thus allow the lights to be turned on and off without affecting the timing circuit.
The foregoing description of the invention has set forth specific details regarding specific components and arrangements of the present invention. In other instances, details of well-known components have been ommitted so as not to unneccessarily obscure the invention. For example, in the preferred embodiment, all of the integrated circuits use CMOS technology. Each chip has buffered inputs with diode clamps. This prevents the signals entering the chips from exceeding a predetermined voltage range and prevents noise spikes. It will be apparent to those skilled in the art that these details can be changed without departing from the spirit of the present invention. For example, and without limitation, in the user interface 24 the switch 34 may be of the rotary or push-button type and additional bits may be programmed, allowing the lights to remain on for longer periods. Also, more than 24 bits may be employed in the shift register. For example, 48 bits would allow the user to program the controller to turn the lights off at 30 minute intervals as opposed to one hour intervals. Any of these options may be employed by those skilled in the art as a matter of design choice, without departing from the spirit of the present invention.
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A controller for outdoor lighting systems turns lights on and off at predetermined times during the day which are designated by a user. The turn on time is set when the user first turns on the lights. The turn off time is fixed by allowing the user to specify the amount of time that the lights will stay lit. The controller repeats the on-off sequence every 24 hours unless it is reprogrammed. Accurate timing is maintained by counting the pulses in standard 120 V, 60 Hz, line current. A manual override is provided which does not interfere with the programmed time sequence.
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FIELD OF THE INVENTION
[0001] The present invention relates to an electret nonwoven filter medium that has been ultrasonically consolidated at a plurality of spots. The present invention further relates to a process for producing the nonwoven filter medium.
BACKGROUND OF THE INVENTION
[0002] Nonwoven webs of electret fibers are typically formed of loosely associated fibers. The filters can be electrostatically charged prior to, during, or after, being formed into a nonwoven web. A particularly effective method of forming a nonwoven electret fiber filter is described in U.S. Reissue Pat. No. 30,782 (Van Turnhout et al.). The electret fibers in this patent are formed from a corona charged film that is fibrillated to form the charged fibers. The charged fibers can then be formed into a nonwoven web by common methods such as carding or air laying. This charging method provides a particularly high density of injected charges. However, problems are encountered with forming webs from these precharged fibrillated fibers. The fibers are generally quite large and uncrimped. They also have a resistance to bending. Due in part to these properties, the fibers resist formation into a uniform coherent web, particularly at low basis weights. U.S. Pat. No. 5,230,800 proposes needle punching of the filter web of fibrillated fibers to a reinforcement scrim so as to produce a filter that has substantially uniform properties across the web. However, the mandatory use of a reinforcement scrim in this method can produce an additional pressure drop of the filter. Also, the obtained uniformity should desirably be further improved. Moreover, because of the needle punching, the manufacturing speed of the filter medium is substantially limited.
[0003] U.S. Pat. No. 4,363,682, provides an alternative method for making a more uniform web. In order to provide a more coherent web, as well as one that resists shedding fibers, this patent proposes a post-embossing treatment. This post-embossing welds the outer surface fibers together allegedly providing a more coherent and comfortable web for use as a face mask. However, this treatment will also tend to result in a more condensed web, which would increase pressure loss over the filter.
[0004] U.S. Pat. No. 5,143,767 describes a thermal spot embossing step to reinforce a nonwoven web of electrostatically charged and fibrillated dielectric fibers so as to obtain a web of high strength which is free from self dusting. The embossing ratio mentioned in this U.S.-patent is between 2 and 35% of the total surface of the filter. U.S. Pat. No. 5,143,767 also mentions that it could be contemplated to use ultrasonic welding instead of thermal embossing of the nonwoven web. However, according to U.S. Pat. No. 5,143,767 this would be difficult and it would not be possible to make thin filters. Also, the filters would allegedly be poor in toughness. Moreover, since ultrasonic equipment is generally limited to fairly narrow width webs, additional difficulties would arise in producing a filter web that has dimensions exceeding the width of typical ultrasonic equipment.
[0005] U.S. Pat. No. 5,900,305 teaches the use of ultrasonic welding techniques to spot laminate a plurality of nonwoven filter webs of melt blown fibers so as to produce a high efficiency filter and disclose arranging several ultrasonic units next to each other so as to be able to weld the laminate across its full width. The different units are then powered by a single controller. It appears that such an arrangement would not be suitable to consolidate a nonwoven filter web so as to produce a filter with uniform properties across its surface.
[0006] U.S. Pat. No. 5,436,054 mentions embossing, ultrasonic welding and needle punching to join a network of reticulated fleeces of electret partially split films together so as to improve the dimensional stability of the electret filter. However, no particular details of these methods are given.
[0007] It is accordingly a desire of the present invention to provide a further method to provide an electret nonwoven filter medium that has uniform properties across its surface and that can be produced at higher speed and therefore at a lower cost. It is further desirable to provide an electret nonwoven filter medium that can be readily converted into a pleated filter with minimum manufacturing burden. The electret nonwoven filter medium can preferably be produced over a broad range of basis weight and preferably has a low pressure drop. Desirably, the performance of the filter medium is improved such as for example the filtration efficiency and particle loading capacity of the filter medium.
DISCLOSURE OF THE INVENTION
[0008] In one aspect, the present invention provides an electret nonwoven filter medium comprising a nonwoven filter web of electrostatically charged fibrillated fibers ultrasonically joined to each other at a plurality of spots distributed across the nonwoven filter web. The total surface occupied by the spots is less than 5% of the surface of the nonwoven filter web, preferably the surface occupied by the spots is in the range of 0.2 to 2, more preferably 0.5 to 1.5%. The shape of the spots is not particularly limited but is generally square, rectangular or circular. The size of each of the individual spots is typically less than 10 −2 cm 2 and is preferably in the range of 10 −3 to 10 −2 cm 2 . The number of spots per cm 2 is at least 2 and is typically in the range of 2 to 5. The number of spots necessary per cm 2 will generally depend on the basis weight of the non-woven filter web with a low basis weight requiring more spots and a high basis weight generally requiring less spots.
[0009] It was found that an electret nonwoven filter medium in accordance with the present invention has highly uniform filter properties across the web and can be produced at an increased speed relative to a method involving needle punching thereby minimizing the manufacturing costs. Furthermore, the use of a scrim layer is not necessary to maintain the uniform filter properties and the electret nonwoven filter medium can be conveniently used to make a pleated filter by ultrasonically welding a netting to the filter medium which will provide the necessary stiffness to the medium so as to be able to pleat the filter medium. The electret nonwoven filter medium was further found to have a good strength and dimensional stability making it suitable for a variety of filter applications. For example, it was found that for a web having a basis weight of at least 50 g/m 2 , ultrasonically welding suffices to obtain a dimensionally stable web without the need for any additional supporting layers such as a netting or a scrim, thus resulting in reduced pressure drop.
[0010] In a further aspect of the present invention, a method is provided to produce a filter medium as described above. In accordance with the method of the present invention to produce the filter medium, electrostatically charged dielectric fibrillated fibers are produced. This can be readily accomplished by the methods that have been described in U.S. Reissue Pat. No. 30,782 (Van Turnhout et al.) and U.S. Reissue Pat. No. 31,285 (Van Turnhout et al.). The method described in these patents comprises feeding a film of a high molecular weight non-polar substance, stretching the film, homopolarly charging the stretched film with the aid of corona elements and fibrillating the stretched charged film. Suitable film forming materials include polyolefins, such as polypropylene, linear low density polyethylene, poly-1-butene, polytetrafluoroethylene, polytrifluorochloroethylene; or polyvinylchloride; aromatic polyarenes; such as polystyrene; polycarbonates; polyesters; and copolymers and blends thereof. Preferred are polyolefins free of branched alkyl radicals and copolymers thereof. Particularly preferred are polypropylene and polypropylene copolymers. Various functional additives known in the art can be blended with the dielectric polymers or copolymers such as poly(4-methyl-1-pentene) as taught in U.S. Pat. No. 4,874,399, a fatty acid metal salt, as disclosed in U.S. Pat. No. 4,789,504, or particulates, as per U.S. Pat. No. 4,456,648.
[0011] The film may be charged in any of the known ways. For example, the film may be locally bilaterally charged by means of corona elements that carry on either side of the film equal but opposite potentials. Thereby the film is charged to almost twice as high a voltage as by means of unilateral charging, at one and the same corona voltage. The charged polymeric film material can be fibrillated in several ways. For example, a needle roller with metal needles running against the film can be used. Thereafter, the continuous fibers may be cut to a desired length.
[0012] The obtained electrostatically charged fibers can then be formed into a nonwoven web layer through carding or air laying or any other web forming process. In order to increase the basis weight to the nonwoven filter web, it may further be subjected to a randomizer or a cross-lapping operation.
[0013] To consolidate the non-woven filter web the fibers are ultrasonically joined to each other at the plurality of spots (at least 2 per cm 2 ) that occupy less than 5% of the surface of the nonwoven filter web. To effect this consolidation, the non-woven filter web is generally transported through a gap that is maintained between an ultrasonic vibrating unit and a mating tool of an ultrasonic device. The gap, i.e., the distance between the vibrating unit and the mating tool of the ultrasonic device is generally kept constant while consolidating the non-woven filter web. By “constant” in this connection is meant that the gap should not deviate more than 20% of the desired value, preferably not more than 10%. If the non-woven filter web has dimensions exceeding 30 cm to 50 cm, it is preferred to put several ultrasonic devices in parallel next to each other along the direction of the web that is perpendicular to the direction in which the web is being transported. Although horns are available today that have a width of up to 60 cm, such horns may not provide the desired uniformity. To produce a highly uniform web when putting two or more horns in parallel, the gap in each of the individual ultrasonic devices (horn-anvil arrangement) is preferably controlled independently. That is, the gap in each of the ultrasonic devices is controlled independent of the gap in another ultrasonic device.
[0014] An ultrasonic device that is particularly suitable for use in connection with the present invention has been described in WO 96/14202 and is commercially available from Herrmann Ultraschalltechnik in Germany. Such an ultrasonic device comprises a rigidly mounted vibrating unit and a mating tool which is preferably a rotating drum. A gap is maintained between the vibrating unit (weld horn) and mating tool (anvil) and this gap can be adjusted prior and during the ultrasonic welding operation through an adjusting device that is also rigidly mounted. The gap between the mating tool and vibrating unit is maintained constant through a controller which steers the adjusting device in response to a measurement that is indicative of a changing gap. For example, the gap can be controlled by an inductively working sensor that is mounted on the rotating anvil drum. Signals from the sensor are wirelessly transmitted to the controller which detects difference with a target value and compensates for any changes via the adjusting device. Alternatively, a force sensor can be included in the vibrating unit to measure the welding force at regular intervals, for example once per revolution of the anvil drum. The controller can then compare the measured force with a target value and adjust the gap if necessary through the adjusting device. This method may be called force control of the gap. In the force control method, the gap may fluctuate because the welding force will depend on the thickness of the web as well as the distance between the horn and anvil. As a result of thickness variations in the web, the gap may fluctuate to keep a target welding force. Force control is the preferred method in this invention. Voltage control is a still further method that can be employed to keep the gap constant. In this method, the vibrating unit and mating tool are part of a low voltage circuit. Shortly before the vibrating unit would touch the anvil drum, the circuit would close and the controller would receive a signal to retract the vibrating unit to a programmed position through the adjusting device. Then the vibrating unit is automatically lowered again step by step until the next retraction is necessary. This loop ensures a precise small gap between the horn and anvil.
[0015] As mentioned above, the mating tool, i.e. anvil, of the ultrasonic device is preferably a rotating drum. The surface of this rotating drum is generally patterned to produce a desired pattern of spots in the nonwoven filter web where the fibers of the web are consolidated. The pattern may be a irregular pattern whereby the spots will be distributed irregular across the web. The pattern may also be regular or a repeating irregular pattern. Examples of patterns that may be used are illustrated below in the drawings.
[0016] The non-woven filter web may be transported on a scrim layer through the gap between the vibrating unit and mating tool of the ultrasonic device if a scrim layer is desired. The scrim material will generally comprise a thermoplastic material such that the scrim layer can be ultrasonically bonded to the non-woven filter web at the spots simultaneously with the consolidation of the nonwoven filter web at the spots. The scrim layer material can be any known reinforcement scrim, woven or nonwoven. Nonwoven scrims are generally preferred in terms of cost and degree of openness. The scrim material is also preferably polymeric, and for purposes of recyclability, preferably formed of a polymer ultrasonically bondable with the material of the electret nonwoven web. A scrim of nonwoven material will generally be treated to increase tensile properties such as by thermoembossing, calandaring, sonic bonding, binder fibers or the like. A typical scrim material would be a spunbond polypropylene nonwoven web. An alternative scrim layer for use in this invention is disclosed in U.S. Pat. No. 5,800,769. The scrim disclosed in this latter patent has discrete individual open areas with an average cross-sectional area as viewed from the plane of the filter media of at least 0.25 mm 2 , generally between 0.25 mm 2 and 10 mm 2 . The weight of this scrim is generally between 0.1 g/m 2 and 0.4 g/m 2 . The scrim disclosed in U.S. Pat. No. 5,800,769 that is preferably used in this invention is a cross laminated web of polyethylene fibers which can be readily ultrasonically bonded to the filter media of this invention. When the non-woven filter web is transported on the scrim layer, the latter will generally underly the filter web. However, it is also possible to include a scrim layer between two or more nonwoven web layers which can then be consolidated and bonded to the scrim layer in the ultrasonic device.
[0017] Alternatively, the non-woven filter web may also be transported on a paper web that is not affected by the ultrasonic welding operation. This paper web can be recollected after the ultrasonic welding operation leaving a ultrasonically consolidated filter web without a scrim layer.
[0018] If a pleatable electret nonwoven filter medium is desired, a netting can be laminated to the non-woven filter medium to provide the necessary stiffness allowing it to be pleated. With the term netting in connection with the present invention is meant a highly open network of fairly thick fibers. Generally the fibers of a netting will have a thickness between 0.5 and 1.5 mm, defining between them generally regularly shaped open areas of an average cross-sectional area between 1 mm 2 and 20 mm 2 . It is a further advantage of the manufacturing method of the present invention that such a netting can be laminated to the nonwoven filter medium simultaneous with the ultrasonic consolidation of the web. In particular, the netting will typically comprise a thermoplastic material and the netting can be transported together with the nonwoven filter web through the gap of the ultrasonic devices where the fibers of the web are ultrasonically joined to each other at the plurality of spots. At the same time, the thermoplastic netting will become ultrasonically bonded to the non-woven filter web at these spots. The thus obtained electret nonwoven filter medium can be pleated by any of the known pleating techniques and is thus suitable for the manufacture of a pleated filter. Accordingly, a pleatable electret nonwoven filter medium with uniform properties can be produced in a convenient and cost effective way. In particular, the method of the present invention is more convenient and cost effective than prior art methods in which the netting material needs to be glued or otherwise laminated to the filter web in a separate lamination step.
[0019] The electret nonwoven filter medium of the present invention may further be laminated to further filter layers. For example, the electret nonwoven filter medium may be laminated with a nonwoven filter layer of melt blown microfibers (BMF layer). The advantage of such a laminate would be that the electret nonwoven filter medium would act as a prefilter to the nonwoven filter layer of melt blown micro-fibers which would otherwise easily get clogged. Thus, the electret nonwoven filter medium of the present invention, which is generally a more open structure then the BMF layer would collect the large particle in a fluid to be filtered and the BMF would filter out particles that would otherwise pass the electret nonwoven filter medium of the invention. The method of the present invention, allows for a convenient, cost efficient and reliable production of such a laminate because the BMF layer can be ultrasonically bonded to the nonwoven filter web while the latter is being ultrasonically consolidated. Furthermore, the filter web of the invention has been found to have an improved efficiency thus resulting in a more effective pre-filter resulting in a longer lifetime of a filter arrangement including such a pre-filter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The invention is further illustrated with reference to the following drawings without however the intention to limit the invention thereto.
[0021] [0021]FIG. 1 is a partial and schematic representation of an ultrasonic device comprising vibrating units and a mating tool in form of a rotating drum.
[0022] [0022]FIG. 2 is an enlarged partial view of the rotating drum as shown in FIG. 1.
[0023] [0023]FIG. 3 is a schematic representation of a second embodiment of a rotating drum.
[0024] [0024]FIG. 4 is a schematic representation of an enlarged portion of the second embodiment of the ultra-sonic device comprising a rotating drum as shown in FIG. 3.
[0025] [0025]FIG. 5 is a planar view of an ultrasonically joined non-woven electret filter medium obtained through the use of an ultrasonic device comprising a rotating drum configuration according to FIGS. 1 and 2.
[0026] [0026]FIG. 6 is a planar view of an ultrasonically joined non-woven electret filter medium obtained through the use of an ultrasonic device comprising a rotating drum configuration according to FIGS. 3 and 4.
[0027] [0027]FIG. 7 is a side view of equipment for the ultrasonic joining of non-woven electret filter media in accordance with FIG. 1.
[0028] [0028]FIG. 8 is a side view of a second embodiment for the ultrasonic joining of a non-woven electret filter medium together with a thermoplastic netting.
[0029] [0029]FIG. 9 is a side view of a third embodiment of ultrasonically joining non-woven filter medium together with a thermoplastic netting and a scrim.
[0030] [0030]FIG. 10 is a side view through an ultrasonic device in accordance with FIG. 1 comprising several ultrasonic vibrating units arranged next to each other.
[0031] [0031]FIG. 11 shows a side view of one of the ultrasonic devices in accordance with FIG. 10 showing one method of a gap control.
[0032] [0032]FIG. 12 shows a diagram of the efficiency versus the dust particle size for non-woven filter media according to the invention in comparison to a needle punched filter medium.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] [0033]FIG. 1 shows a device 10 for the ultrasonic joining of an electret non-woven filter medium 12 . The basic components of the device are vibrating units 14 , 16 in the form of weld horns driven by driving units. Typically several weld horns 14 , 16 are arranged next to each other to allow an ultrasonic joining of a relatively wide electret non-woven filter medium 12 . The weld horns 14 , 16 cooperate with a mating tool or an anvil, which in this embodiment has the form of a rotating drum 18 . Only the drum 18 itself and its axle 20 are shown in FIG. 1. The rotating drum 18 has an outer, essentially cylindrical surface 22 , which is provided with a multiplicity of protrusions 24 . During the ultrasonic joining the electret non-woven filter medium is moving in the direction of arrow 26 and the rotating drum in the direction of arrow 28 . The weld horns 14 , 16 and the protrusions 24 of rotating drum 18 are arranged in a manner that they form a small gap (with the filter medium placed between the weld horns 14 , 16 and the protrusions 24 of the drum) the gap being so small that at the points of the protrusions 24 the energy density is high enough to achieve the ultrasonic welding.
[0034] [0034]FIG. 2 shows an enlarged view of the surface 22 of the rotating drum 18 and the protrusions 24 . These protrusions are integrally formed with the surface 22 of the rotating drum through generally known methods such as machining, spark welding and the like. The rotating drum is up to one meter or more in length and it has a diameter of several decimeters.
[0035] An alternative method is shown in FIGS. 3 and 4. The rotating drum 18 with its axle 20 is provided with a spiral grove 30 as can be seen from FIG. 3. Separately a metal band 32 of a substantial length is manufactured through conventionally known methods such as machining or stamping. Typically a band of a given width 34 is unwound from a supply roll and passed through a stamping equipment. The configurations as shown in FIGS. 3 and 4 are punched out creating a sequence of protrusions 36 which may have a trapezoidal cross-section. FIG. 4 shows, similar to FIG. 1, a portion of rotating drum 18 with a spirally wound grove (not shown) into which the band 32 has been inserted. This is done in a manner that the protrusions 36 with the upper surface 38 form a pattern which is similar to the pattern depicted in FIG. 2 where protrusions 24 have been created on surface 22 of rotating drum 18 .
[0036] Band 32 is spirally wound into the grove of the rotating drum 18 to achieve a staggered configuration of protrusions 36 as can be seen on FIG. 4. The intention is to have 2 adjacent protrusions 40 , 42 of one row placed in a manner that the protrusion 38 in the next row is arranged between the protrusions 40 and 42 , preferably centrally between them. Resulting welding patterns on the filter web can be seen from FIGS. 5 and 6. FIG. 5 shows the planar view onto the ultrasonically joined electret non-woven filter medium 44 with a substantially regular arrangement of the welding spots 46 . FIG. 6 shows the corresponding filter medium 48 with welding spots arranged in a somewhat irregular but repeating pattern. Due to the spiral winding of band 32 welding spot 50 for example is not exactly arranged between the welding spots 52 , 54 of the subsequent row. Therefore, the appearance of a filter medium 48 produced with a rotating drum according to FIGS. 3 and 4 is different. For the functionality of the electret filter media, this is of no considerable significance.
[0037] The size and number of protrusions 24 according to FIGS. 1 and 2 and the size and number of protrusions 36 , 38 according to FIGS. 3 and 4 is such that the total surface occupied by the protrusions is less than 5% of the surface of the rotating drum which results in about the same percentage on the ultrasonically joined non-woven filter medium. In accordance with the invention, the number of welded spots per cm 2 on the non-woven filter medium should be greater than 2. In case of FIGS. 3 and 4, for example, bands 32 will have a width of 0.6-1.0 mm, preferably 0.8 mm. Further, the surface area at the end of the protrusions 36 , 38 can be either circular, elliptic, quadratic, rectangular or of other shapes. In a particular embodiment a square configuration would be preferred having the same dimension as the width of the band namely 0.6-1.0 mm preferably, 0.8 mm. The distance between two adjacent protrusions as for example between the protrusions 40 and 42 in FIG. 4 can be in the order of 6-10 mm, preferably 7 mm, and the distance between adjacent bands can be in the range of 4-6 mm, preferably 5 mm. This is then the distance between two adjacent turns in the spiral grove as depicted in FIG. 3. In principle the same applies for the embodiment as depicted in FIGS. 1 and 2 where the protrusions are machined, spark eroded or otherwise generated. The dimensions are in principle identical. The numbers as given above serve only as a general guideline for a preferred configuration, the decisive feature, however, is that the total surface area of the contact portions of the protrusions is below 5% of the surface of the rotating drum, preferably below 2% and that the number of spots per cm 2 is at least 2.
[0038] FIGS. 7 - 9 show side views of the equipment used for the ultrasonic joining of the fibers and other components of electrostatic non-woven filter media. The filter medium 12 is obtained from generally known equipment 60 which produces a non-woven filter web of electrostaticaly charged fibrillated fibers. These fibers are guided to the ultrasonic device 10 as depicted in FIGS. 1 - 4 and described above. The vibrating unit in the form of a weld horn 14 is driven by the unit 62 which includes all features necessary to generate the ultrasonic vibrations as well as means to control the gap. The weld horn 14 corresponds with the mating tool or anvil which has the form of drum 18 rotating in the direction 28 as explained above. The ultrasonically treated web 44 is taken up by the roller 64 . The ultrasonically treated web 44 passes through a pair of rollers 66 , 68 which simultaneously or additionally also can take over the function of cutting web 44 for example on the 2 sides which may not be welded or otherwise useless and furthermore, there may be additional cutting knives along the width of web 44 in order to generate smaller portions of the ultrasonically treated web 44 which are rolled up by roller 64 .
[0039] The entrance of the untreated web 12 into the ultrasonic unit 10 is depicted in more detail with the enlarged section A. It can be seen that the weld horn 14 with its lower end 70 and the protrusion 24 on the rotating drum 18 form a gap 72 . Furthermore, it can be seen that the incoming web 12 is significantly thicker than the outgoing ultrasonically treated web 44 . When entering the gap 72 the incoming web 12 is compressed which can be seen from the portions 74 and 76 . This compression either takes place automatically or with the help of additional guidance means (not depicted). Furthermore, the weld horn 14 may be significantly wider than the protrusion 24 . There is generally no structure on the lower surface 70 of weld horn 14 .
[0040] The cross-sectional configuration of the ultrasonically treated web 44 is shown in the enlarged portion B. The fibers of web 44 have been ultrasonically joined at the portion 78 and there are smooth transitions 80 and 82 between the welded portion and the normal portion of web 44 . Furthermore, it can be seen that the thickness of the ultrasonically treated web 44 is significantly smaller than that of the original web 12 resulting from the ultrasonic treatment. It can also be seen that the welded portion 78 has indents on both sides, the upper side and the lower side, although only the protrusions 24 are in contact with the web 12 on the lower side, however, a total compression occurs which causes the upper portion to be compressed so that transitions on both sides 80 and 82 are observed.
[0041] [0041]FIG. 8 shows an alternative arrangement for the ultrasonic equipment. Also here the original web 12 is obtained from the unit 60 and guided to the ultrasonic device 10 which is shown in a reversed arrangement. The rotating drum 18 is on the upper side and the weld horn 14 and the corresponding driving unit 62 are on the lower side. The essential difference is that in addition to the originally untreated web a second layer 84 is guided onto the ultrasonic device 10 through the use of the dispenser roll 86 and two guidance rolls 88 and 90 . This additional layer 84 is a netting onto which the web can be ultrasonically bonded. Netting 84 and web 12 are joined to yield the configuration 92 which is taken up by the take-up roller 64 and the guidance rolls 66 and 68 .
[0042] The difference relative to the embodiment shown in FIG. 7 can be seen again with the two enlarged portions C and D. The original web 12 and the netting 84 are guided to the gap 72 created by the weld horn and the protrusion 24 of the drum 18 to generate the laminate 92 . Also here a guidance and a compression of web 12 and netting 84 at the portions 74 and 76 can be seen. The compression takes place primarily on the original web 12 while the netting is only slightly compressed during the ultrasonic welding procedure. The enlarged view D shows a similar configuration as the view B in FIG. 7 also showing the portion 78 compressed through the ultrasonic welding and the transition areas 80 and 82 .
[0043] [0043]FIG. 9 shows a third configuration of the ultrasonic equipment the numerals being the same as in the preceding figures. The added feature here is that a third layer 94 is supplied from the roller 96 . This is a scrim layer. In this case the ultrasonic device 10 is again arranged in the same sense as in FIG. 7, this essentially depends on the practicability in the process. Portion E is in principle comparable to portions A and C in FIGS. 7 and 8 respectively. Portion F shows again that there is a three-layer configuration with the netting 84 , the filter web 12 and the scrim 94 altogether being combined to the laminate 98 which then is taken up be roller 64 in the same manner as described above. It should be noted that these are three typical configurations, however, a multiplicity of further variations can be contemplated, for example a multiplicity of layers including layers of spun bond fibers or melt-blown fibers.
[0044] [0044]FIG. 10 provides a side view of the ultrasonic equipment in accordance with the preceding figures showing the rotating drum 18 with its axis 20 on the lower side and the weld horns 14 with driving units 62 on the other side, all of them being arranged so that the web 12 can pass therebetween. The ultrasonic equipment includes four individual ultrasonic vibrating devices 100 , 102 , 104 , 106 all operating independently of each other. Each of them is equipped within the driving unit 62 , with a sensor 108 for monitoring the gap between horn and anvil and an actuator 110 . Sensor 108 and actuator 110 are electrically connected through electrical wirings 112 and 114 to an electronic control unit 116 which ensures that the gap 72 is maintained within tolerances which are small enough in order to ensure an ultrasonic joining of the components of the web 44 or laminate 92 , 98 and further prevents horn and anvil from touching each other. These controls are handled independently for each individual ultrasonic vibrating system 100 , 102 , 104 and 106 . Control unit 116 is then connected to a central power supply unit 118 .
[0045] [0045]FIG. 11 shows an individual ultrasonic vibrating system, e.g. component 100 in FIG. 10. There are different types of control that can be utilized, the most preferred one is the so-called force control. The two main purposes of this equipment are to generate the vibrations for the ultrasonic welding and to ensure the control of gap 72 between the rotating drum 18 and the weld horn 14 . As shown in FIG. 10, the driving unit 62 comprises a sensor 108 and an actuator 110 . For the explanation of the control for the gap 72 further details are shown in FIG. 11. Actuator 110 provides the vibration for weld horn 14 . Furthermore, a force sensor 108 is in contact with either the actuator 110 or directly with the weld horn 14 . Its purpose is to sense the force that the weld horn is actuating onto the material to be joined. This sensor can be of any type for example some kind of a piezzo sensor. The force signal is passed to the electronic control unit 116 through the electrical connection 112 . If the electronic control unit 116 identifies that the measured force is below a preset threshold value the entire system comprising actuator 110 sensor 108 and weld horn 14 is moved downwards through the driving means 120 which is electrically connected to the electronic control unit 116 through the wiring 122 . Actuator 110 is connected through the wiring system 124 in a manner that a relative movement between control unit 116 and actuator 110 is possible. The weld horn 14 is also electrically connected to the electronic unit control through the wiring 126 which is also flexible. Rotating drum 18 is connected at its axis 20 to the electronic control unit 116 through wiring 128 . As soon as the horn 14 makes contact with the protrusion or any other portion of the rotating drum 18 an electrical short circuit is created and sensed through the wirings 126 , 128 . The electronic control unit 116 then ensures that a minimum gap 72 is restored.
[0046] In accordance with the process of the invention, the materials to be joined ultrasonically are passing through gap 72 (not shown, see preceding figures) and the control mechanism operates in the following manner: If sensor 108 senses a force that is too low actuator 110 is moved down through driving means 120 until the threshold value for the force is obtained. The same occurs in the opposite direction when the force is too high. Accordingly a continuous control of the gap 72 is ensured by using conventional electronic control systems. Furthermore, the additional control of the conductivity between weld horn 14 and rotating drum 18 ensures that a minimum gap is maintained thus avoiding horn and anvil touching each other.
[0047] An alternative method for controlling the gap is to sense the distance between the weld horn 14 and the surface of the rotating drum 18 through a sensor that is placed within the rotating drum 18 . Further details on ways to control the gap are found in WO 96/14202.
EXAMPLES
[0048] The invention will be further described by the following examples and test results:
Example 1
[0049] A scrim layer 94 (see FIG. 9) was used comprising a non-woven spun-bonded material produced in a known manner from fibers being multiple thermally bonded and randomly arranged. The basis weight of this non-woven spun-bonded material was 10 g/m 2 . The spun-bonded web was combined with a non-woven material of the electret filter material consisting of electrostaticaly charged dielectric fibrillated or split fibers with the typical dimensions of 10 by 40 microns in a side view. The basis weight of this non-woven material was about 30 g/m 2 . As materials for this electret filter layer products distributed under the designation of 3M Filtrete™ by the Minnesota, Mining and Manufacturing Company were used. The two layers, the scrim layer with a basis weight of 10 g/m 2 and the electret filter layer with a basis weight of 30 g/m 2 , were then ultrasonically joined using a process as shown in FIG. 8 utilizing an equipment as described therein with a rotating drum of the above given dimensions according to FIGS. 3 and 4 with top areas 38 of the bands 32 of 0.81×0.81 mm and a spacing between two adjacent protrusions 38 of 6.9 mm and a distance between 2 subsequent rows of 4.83 mm. This results in a portion of the ultrasonically joined area of the filter web of 1.5% of the total area in the rotating drum corresponding to about 2% of the area in the web due tot the fact that the portion of ultrasonically joined fibers is slightly larger in area than the portion of the rotating drum. The number of spots per cm 2 is about 2.3. The thus bonded laminate of filter media and scrim was adhered to a thermoplastic netting or a reticular support structure. This netting consists of fibers having a diameter of about 0.45 mm. The openings of the support structure are diamond shaped and have a size of about 3.6×4.1 mm. The thickness of the support structure is about 0.85 mm. The fibers consist of polypropylene or other polymers. The netting or reticular support structure was adhered to the laminate of the fiber media and scrim utilizing conventionally used adhesives. The thus obtained structure was then pleated and formed into a filter with a pleat height of 25 mm, pleat spacing of 9.4 mm and total dimensions of the filter of 290×100 mm resulting in 31 pleats. This construction was then appropriately mounted into a frame by gluing or insert-molding.
Example 2
[0050] This Example differs from Example 1 only by the basic weight of the electret non-woven filter media which was chosen to be 40 g/m 2 so that together with the scrim of 10 g/m 2 a total basic weight of 50 g/m 2 was obtained.
Example 3
[0051] Example 3 is similar to Example 2 except that in addition to a scrim layer, a netting was also ultrasonically welded to the web which had a weight of 50 g/m 2 . This configuration was ultrasonic joined according to the process illustrated in FIG. 9.
Example 4
[0052] Example 4 differs from Example 3 by the fact that the scrim was omitted. The basic weight of the web was chosen to be 50 g/m 2 , the netting was as described above and the ultrasonic treatment was done as described in FIG. 8.
COMPARATIVE EXAMPLE
[0053] A larger number of Comparative Examples was created in the same manner as for the Examples 1-4 essentially differing in that a needling process was used instead of the ultrasonic bonding. For the comparison comparative samples were chosen that showed the same pressure drop as Examples 1-4. Thus filters with essentially the same initial performance were compared.
[0054] With the above described sample filters comparative measurements were conducted.
[0055] The efficiency was measured in accordance with the test norm DIN 71 460, part 1.
[0056] The measurement of the efficiency is conducted as follows: A test dust “coarse” according to DIN ISO 5011 is introduced according to §4.4 of DIN 71 460. This dust is measured with particle counters prior and after the entry through the filter to be tested. The particle counters have the capability of determining particles of different particle sizes ranging between 0.5 and 15 microns at least. The ratio within this particle range then is the efficiency in percent. All provisions according to DIN 71 460, §1-4.4.2, were taken into account. It is particularly important that the filters to be tested are identical in size and configuration as stated above for the different examples.
[0057] The results can be taken from FIG. 12. It shows Examples 1, 2 and 4 compared with the Comparative Example. It can be seen that for the tested range of particle sizes between 0.1 and 10 microns the efficiency is increased by about 10 percentage points.
[0058] Furthermore, the captured dust was determined for all 4 examples in comparison with the reference example. Also in this case the tests were conducted following the test norm DIN 71 460 part 1.
[0059] The determination of the captured dust was conducted as follows: All provisions of DIN 71 460, part 1, were taken into account which are relevant for the determination of the captured dust, especially §6.3. The measurement was carried out from an initial pressure drop until the pressure drop had been increased to a level of 25, 50, 75 and 100 Pa respectively. The filters were weighed prior and after the test. In this specific case the ratios between the Examples 1-4 and the Comparative Example were taken into account and the percentage increase of the captured dust with respect to the Comparative Example was determined. For the weighing also DIN ISO 5011 was to be applied.
[0060] The results are listed in Table 1, which shows the additional loading as compared to the needle type Comparative Example. The different steps are resulting in an increase of the pressure drop of 25, 50, 75 and 100 Pa respectively. It can be seen that the most significant improvement was obtained with Example 4, which did not include a scrim layer.
TABLE 1 Loading step: Increase of pressure drop in Pa Example 1 Example 2 Example 3 Example 4 Initial (+0 Pa) 100% 100% 100% 100% +25 Pa 162% 148% 117% 260% +50 Pa 139% 134% 109% 217% +75 Pa 148% 139% 113% 229% +100 Pa 152% 139% 112% 234% Average 150% 140% 113% 235%
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The present invention provides an electret nonwoven filter medium comprising a nonwoven filter web of electrostatically charged fibrillated fibers ultrasonically joined to each other at a plurality of spots distributed across said nonwoven filter web, the total surface occupied by said spots being less than 5% of the surface of said nonwoven filter web and the number of spots per square centimeter being at least 2. The present invention also provides a method of making the electret nonwoven filter medium.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority of U.S. Provisional Patent Application Ser. No. 60/238,297, filed on Oct. 6, 2000.
TECHNICAL FIELD
This invention relates to optical communications, and in particular to a method of optical domain clock signal recovery from high-speed data, which is independent of the data format or the optical signal rate.
BACKGROUND OF THE INVENTION
Optical fiber networks are in widespread use due to their ability to support high bandwidth connections. The bandwidth of optical fibers runs into gigabits and even terabits. Optical links can thus carry hundreds of thousands of communications channels multiplexed together.
One of the fundamental requirements of nodal network elements in optical networks is the capability to extract the line rate clock from the incoming signal. Presently, this is achieved by converting the incoming optical signal into an electrical signal followed by clock extraction using an application specific electronic circuit. As optical networks become increasingly transparent, there is a need to recover the line rate clock from the signal without resorting to Optical-to-Electrical, or O-E-O, conversion of the signal.
Future optical networking line systems will incorporate service signals at both 10 Gb/s, 40 Gb/s and much higher data rates, along with the associated Forward Error Corrected (FEC) line rate at each nominal bit rate. The FEC rates associated with, for example, 10 Gb/s optical signal transport include the 64/63 coding for 10 Gb/s Ethernet, the 15/14 encoding of SONET-OC192 FEC, and the strong-FEC rate of 12.25 Gb/s. As these networks tend towards optical transparency, the nodal devices in the optical network must work with any commercially desired line rate, independent of format, whatever that is or may be. Thus, one of the fundamental functions these devices must provide is the capability to extract the clock from an arbitrary optical signal. Moreover, to maintain the high speeds of modern and future data networks, as well as increase efficiency, this clock recovery must be done completely in the optical domain.
In future All Optical Networks (AON) the same network element will need to handle both 10 Gb/s and 40 Gb/s. Consequently, the clock recovery in these network elements must be tunable over a wide range of frequencies.
Previous embodiments of clock recovery systems are experimental in nature, and relegated to research laboratories. They do not include the possibility of recovering the line rate clock from the various ubiquitous NRZ data formats. Additionally, any tuning of the clock signal is done using a linear phase section.
What is therefore needed is an all optical clock recovery system that can operate upon any given optical signal, regardless of its format or bit rate. What is further required is a system that exploits non-linear optical elements to reshape the clock output for optimal retiming of the various data formats.
SUMMARY OF THE INVENTION
A method and circuit are disclosed for the recovery of the clock signal from an arbitrary optical data signal. The method involves two stages. The first stage consists of a Semiconductor Optical Amplifier—Asymmetric Mach-Zehnder Interferometer, or SOA-AMZI, preprocessor, which is responsible for transforming an incoming NRZ type signal into a pseudo return to zero (“PRZ”) type signal, which has a significant spectral component at the inherent clock rate.
This preprocessing stage is followed by a second stage clock recovery circuit. In a preferred embodiment the second stage is implemented via an SOA-MZI circuit (symmetric in structure, i.e., no phase delay introduction in one of the arms) terminated by two Distributed Feedback (DFB) lasers that go into mutual oscillations triggered by the dominant frequency of the first stage's output signal. The SOA-MZI is tuned to adjust the input phase of the oscillatory signal into the DFBs. This provides the tuning and control of the oscillation frequency of the output clock signal. The SOA gain currents can be adjusted to reshape the clock signal, which is the output of the second stage.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a circuit implementing the method of the present invention;
FIG. 2 depicts just the second stage of the circuit of FIG. 1; and
FIG. 3 depicts an exemplary semiconductor optical amplifier device used according to the method of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The above described and other problems in the prior art are solved in accordance with the method, apparatus, circuit and devices of the present invention, as will now be described.
Most, if not all, optical networks currently operating transmit some or all data as NRZ signals. In the case of the NRZ signal format, the RF spectrum reveals no spectral component at the line rate. This is a simple consequence of the format. The RF spectrum of an ideal NRZ signal looks like the mathematical sinc function with the first zero at the line rate.
On the other hand, the RF spectrum of an RZ signal reveals a strong spectral component at the line rate. Consequently, an incoming RZ signal can be operated upon directly to extract the clock signal.
The fundamental problem of all-optical clock recovery from an arbitrary incoming optical signal is thus the passing of an RZ signal without attenuation, and the generation of a RF spectral component at the line rate for a NRZ signal. For an NRZ signal of unknown bit rate and format, an NRZ/PRZ converter is used to generate this latter spectral component by converting the incoming NRZ into a pseudo return to zero, or PRZ signal.
Once the incoming signal has a significant spectral component at the line rate, optical oscillations can be triggered to obtain a pure line rate optical clock signal.
FIG. 1 depicts a preferred embodiment of the two circuit stages needed for all optical clock recovery of an arbitrary NRZ signal. For various design considerations, most data in optical data networks is currently sent in the NRZ format. The first stage 150 , converts an input signal 100 to PRZ format, where PRZ denotes a “pseudo return to zero” or PRZ data format. The PRZ signal is generated from a standard NRZ format input signal 100 by generating an RZ like pulse each time the NRZ signal transitions, whether from high to low or from low to high, i.e. PRZ has a pulse at each rising edge and at each falling edge of the original signal.
As above, the key property of a PRZ signal is that its RF frequency spectrum has a significant frequency component at the original NRZ signal's clock rate. It is this very property that the method of the invention exploits to recover the clock signal.
The actual conversion of an NRZ signal to the PRZ format is the result of the operation of a PRZ generator 150 on an NRZ input. A related patent application, under common assignment with the present one, describes in detail a method and circuit for implementing the preprocessor of the first stage 150 . That patent application is entitled “FORMAT INSENSITIVE AND BIT RATE INDEPENDENT OPTICAL PREPROCESSOR” by Bharat Dave, et al., filed on May 4, 2001. That disclosure is hereby fully incorporated herein by this reference. The method and circuit described therein will thus be summarily described here for purposes of reference.
The PRZ generator forms the first stage 150 of the All Optical Clock Recovery (“AOCR”) scheme. This stage consists of a path-delayed Asymmetric Mach-Zehnder Interferometer (AMZI). The AMZI incorporates semiconductor optical amplifiers (SOAs) in each of its arms 105 and 106 , respectively, and a phase delay element 107 in one, but not both, of the two arms; hence the asymmetry. The AMZI is set for destructive interference of the signals in the two paths. Thus, the interference of a high bit with its path delayed inverse, i.e. a low bit, generates an RZ-like bit at both the leading and falling edges of the original high bit. This latter signal, with a bit rate effectively double that of the original NRZ bit rate, is the PRZ signal 110 .
This effective doubling of the bit rate leads to the generation of a large component of the line rate frequency in the RF spectrum of the output signal 110 of the AMZI 150 . Generally, unless the input signal is exceptionally aberrant, this line rate frequency will be the far and away dominant frequency in the spectrum. Since the preprocessor does not need to know the actual bit rate or format of the input data, it is data rate and format insensitive.
Thus the preprocessor has the ability to reshape the PRZ signal as well as adjust its duty cycle. The output 110 of the first stage 150 becomes the input to the second stage 160 . In a preferred embodiment, the second stage 160 comprises a symmetric Mach-Zehnder Interferometer, where each arm contains a semiconductor optical amplifier 111 and 112 , respectively.
The principle of clock recovery is based on inducing oscillations between the two lasers DFB 1 113 and DFB 2 114 . The oscillations are triggered by the output of the first stage 110 . As described above, this output can be either RZ or PRZ. The current to DFB 2 114 is tuned close to its lasing threshold, with DFB 1 113 energized so as to be in lasing mode. Thus the trigger pulse 110 induces lasing in DFB 2 114 . The feedback from DFB 2 114 turns off the lasing in DFB 1 113 resulting in DFB 2 114 itself turning off. The reduced feedback from DFB 2 114 now returns DFB 1 113 to lasing. In this manner the two lasers mutually stimulate one another in oscillation. Recalling that the dominant frequency in the input signal 110 is the original signal's 100 clock rate, pulses from the input 110 are sufficient to lock the oscillation of the DFB lasers at that rate, and, in general, to hold for quite a number of low bits (such as would appear where the original signal 100 had a long run of high bits). Thus, the forced triggering by the PRZ/RZ input 110 locks the phase of the oscillations at the original signal's 100 clock rate.
The interferometer improves the control of the phase input to DFB 2 114 .
The use of the SOA-MZI facilitates the tuning of the oscillation rate by adjusting the input signal phase into DFB 2 114 . As the phase of the MZI output is tuned, the gain recovery time of DFB 2 114 is adjusted. This results in the oscillation rate being altered. In this manner the clock frequency can be tuned to the desired line rate. Using non-linear SOA elements also allows shaping of the output clock with a lesser energy expenditure. Moreover, by adjusting the currents in each of the two SOAs in the second stage interferometer, the refractive index of each SOA's waveguide can be manipulated, thus altering the phase of the pulse entering DFB 2 114 . Thus, the oscillation rate of the circuit can be altered, and the identical circuit can be tuned to the various bit rates available in the network, thus rendering the system bit rate independent.
The use of the SOA-AMZI in the first stage 150 of the clock recovery system allows the input power required by the device to be quite nominal, in the embodiment depicted approximately −10 dBm; thus signal pre-amplification concerns are diminished or avoided. The output power of the clock signal in this embodiment is on the order of 0 dBm. The laser wavelength of the all-optical clock signal is a function of the wavelength amplification spectrum of the second stage SOAs. With suitably designed SOAs, the standard carrier frequencies used in optical networks all fall within the SOA amplification spectrum. This wavelength can be anywhere in the amplification window of the SOAs in the second stage 160 SOA-MZI circuit. Thus, as examples, for the C-band of optical transmission a wavelength such as 1550 nm may be chosen, and for the L-band of optical transmission a wavelength such as 1585 nm may be chosen.
In a preferred embodiment, Multimode Interference (MMI) couplers with a 50:50 splitting ratio (commonly known as 3 dB couplers) make up the couplers of the first stage 102 and 103 , respectively, as well as the couplers of the second stage 120 and 125 , respectively.
FIGS. 2 and 2A show the second stage clock recovery circuit in isolation. The input 200 to this stage, at the top left of the figure, is the amplified RZ or PRZ signal output from the first stage. The stage comprises a symmetric interferometer, with an SOA 210 and 215 , respectively, in each arm. The interferometer has two DFB lasers as termini, DFB 1 205 , in lasing mode, and DFB 2 220 near the lasing threshold. This state of affairs results in an optical cavity that is sensitive to the incoming input signal such that self-pulsating behavior will be triggered by any incoming data pulse.
The input signal 200 , which has a large, usually far and away dominant, frequency component at the original optical signal's clock rate, thus triggers the DFB lasers 205 and 220 into self pulsating behavior at that frequency, and the feedback between the two lasers results in a pendulum like behavior that maintains the two lasers in a conservative self oscillatory state. This self oscillation is thus maintained for some time, due to the mutual interaction of the lasers, even if the incoming data has numerous “zero” bits in a row (and thus no pulses at all for that interval). Thus the output signal of the second stage 225 is an optical clock signal at the original line rate of the optical input signal 100 in FIG. 1 .
In general the clock signal can be “locked” on to after the second stage MZI has been fed ten (10) or more “one” bits from the input signal. As well, due to the conservative mutual feedback and self oscillation of the lasers (which preserve their oscillation rate even in the absence of continually added energy from the RZ/PRZ input signal 110 ), the output clock signal 225 can be maintained even during significant periods of no second stage input signal 200 , such as in the event of 100 “zero” bits, a statistically very rare occurrence, and under some data formats, (where scrambling is done prior to transmission over a link, and descrambling at the receiving end), quite impossible. Thus the mutual feedback and self oscillation of the two lasers presents a robust structure for extracting a clean optical clock signal as its output 225 .
The method of the invention can be implemented using either discrete components, or in a preferred embodiment, as an integrated device in InP-based semiconductors. The latter embodiment will next be described with reference to FIG. 3
FIG. 3 depicts a cross section of an exemplary integrated circuit SOA. With reference to FIG. 1, FIG. 3 depicts a cross section of any of the depicted SOAs taken perpendicular to the direction of optical signal flow in the interferometer arms. Numerous devices of the type depicted in FIG. 3 can easily be integrated with the interferometers of the preprocessor, so that the entire circuit can be fabricated on one IC. The device consists of a buried sandwich structure 350 with an active Strained Multiple Quantum Well region 311 sandwiched between two waveguide layers 310 and 312 made of InGaAsP. In an exemplary embodiment, the λ g of the InGaAsP in layers 310 and 312 is 1.17 μm. The sandwich structure does not extend laterally along the width of the device, but rather is also surrounded on each side by the InP region 304 in which it is buried.
The active Strained MQW layer is used to insure a constant gain and phase characteristic for the SOA, independent of the polarization of the input signal polarization. The SMQW layer is made up of pairs of InGaAsP and InGaAs layers, one disposed on top of the other such that there is strain between layer interfaces, as is known in the art. In a preferred embodiment, there are three such pairs, for a total of six layers. The active region/waveguide sandwich structure 350 is buried in an undoped InP layer 404 , and is laterally disposed above an undoped InP layer 303 . This latter layer 303 is laterally disposed above an n-type InP layer 302 which is grown on top of a substantially doped n-type InP substrate. The substrate layer 301 has, in a preferred embodiment, a doping of 4-6×10 18 /cm −3 . The doping of the grown layer 302 is precisely controlled, and in a preferred embodiment is on the order of 5×10 18 /cm −3 . On top of the buried active region/waveguide sandwich structure 350 and the undoped InP layer covering it 304 is a laterally disposed p-type InP region 321 . In a preferred embodiment this region will have a doping of 5×10 17 /cm −3 . On top of the p-type InP region 321 is a highly doped p+-type InGaAs layer. In a preferred embodiment this latter region will have a doping of 1×10 19 /cm −3 . The p-type layers 320 and 321 , respectively, have a width equal to that of the active region/waveguide sandwich structure, as shown in FIG. 3 .
As described above, the optical signal path is perpendicular to and heading into the plane of FIG. 3 .
Utilizing the SOA described above, the entire all-optical clock recovery device can be integrated in one circuit. An exemplary method of effecting this integration is next described.
After an epiwafer is grown with the waveguide and the SOA active regions, the wafer is patterned to delineate the SOAs, the AMZI and the MZI. In a preferred embodiment the path length difference between the two arms of the AMZI is approximately 1 mm.
Next, the DFB regions of the second stage of the device are created using either a holographic or a non-contact interference lithographic technique. The periodicity of the grating in a preferred embodiment is approximately 2850A. The grating is of Order 1 and provides optical feedback through second-order diffraction. The undoped InP top cladding layer, the p-type InP layers, and the contact layer are then regrown on the patterned substrate. This step is then followed by photolithography for top-contact metallization. The device is then cleaved and packaged.
While the above describes the preferred embodiments of the invention, various modifications or additions will be apparent to those of skill in the art. Such modifications and additions are intended to be covered by the following claims.
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A method and circuit are presented for the all optical recovery of the clock signal from an arbitrary optical data signal. The method involves two stages. A first stage preprocesses the optical signal by converting a NRZ signal to a PRZ signal, or if the input optical signal is RZ, by merely amplifying it. In a preferred embodiment this stage is implemented via an integrated SOA in each arm of an asymmetric interferometric device. The output of the preprocessing stage is fed to a clock recovery stage, which consists of a symmetric interferometer that locks on to the inherent clock signal by using the second stage input signal to trigger two optical sources to self oscillate at the clock rate. In a preferred embodiment the second stage is implemented via SOAs integrated in the arms of an interferometer, with two DFB lasers as terminuses. The output of the interferometer is an optical clock signal at the clock rate of the original input.
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TECHNICAL FIELD
The present invention relates to a microscope technology that observes a sample surface topology using electrons.
BACKGROUND ART
There is an electron microscope as an observation device for magnifying a sample surface topology. The operation of a scanning electron microscope (in the following, referred to as an SEM) is shown. Primary electrons accelerated by a voltage applied to an electron source are focused at an electron lens, and the focused primary electrons are scanned over a sample using a deflector. Secondary electrons emitted from the sample by irradiating the primary electrons are detected at a detector. Secondary electron signals are detected in synchronization with scanning signals to form an image. The amount of the secondary electrons emitted from the sample is varied depending on the sample surface topology.
In the case where a sample is an insulator, the sample surface inevitably becomes charged due to the irradiation of electrons. Charging due to the irradiation of electrons causes an image drift under observation, for example, to produce an image failure.
A method is known as a method for addressing an image failure caused by the charging in which an electric conductor is coated over the sample surface. Metals such as gold and platinum are used for the electric conductor. Moreover, Patent Literature 1 discloses a method in which a sample is applied with an ionic liquid hardly volatilized in a vacuum to provide electrical conductivity on the electron irradiation surface. Furthermore, Patent Literature 2 discloses a low-energy SEM that can provide stable observation using low-energy electrons even with charging.
CITATION LIST
Patent Literature
Patent Literature 1: International Publication No. WO2007/083756
Patent Literature 2: Japanese Patent Application Laid-Open Publication No. 2000-195459
SUMMARY OF INVENTION
Technical Problem
In these years, with a high resolution SEM, a low-energy SEM is used for inspection and measurement of a sample surface topology. However, even though low-energy electrons are used, the sample surface is charged. Thus, in the case where a sample surface topology is in a microstructure, an image failure due to charging such as the elimination of a contrast at the edge portion becomes a problem. In the case where a metal film is coated over an insulator sample in order to suppress an image failure in a low-energy SEM, a contrast caused by the grain boundary of the metal film is superposed on the shape contrast of the sample. Moreover, in the case where an ionic liquid is applied to the electron irradiation surface, the entire pattern surface is filled with the ionic liquid, and it is not enabled to observe the sample surface topology using a low-energy SEM.
It is an object of the present invention to provide an observation specimen for an electron microscopic method, an electron microscopic method, an electron microscope, and an observation specimen preparation device that address the problems above and suppress an image failure due to charging.
Solution to Problem
In order to address the problems above, in an observation specimen for an electron microscopic method according to the invention of the present application, a liquid medium including an ionic liquid on a sample is in a thin film shape or in a mesh film shape. The thin film or mesh film of the liquid medium including an ionic liquid of the observation specimen is coated according to a sample shape whether the film is along the sample surface topology or a low-energy primary electron can pass through the film thickness, so that a clear edge contrast can be obtained.
Here, in the observation specimen according to the invention of the present application, a film thickness of a portion to which the liquid medium including an ionic liquid is applied is one monolayer or more and 100 monolayers or less. One monolayer means the thickness of a single molecular layer of an ionic liquid.
Moreover, an electron microscopic method according to the invention of the present application includes the steps of: measuring a film thickness of a liquid medium including an ionic liquid in a thin film shape or in a mesh film shape on a sample; and controlling an irradiation condition for a primary electron based on the film thickness of the liquid medium including an ionic liquid. According to this method, the irradiation condition for a primary electron can be controlled according to the film thickness of the liquid medium including an ionic liquid, so that the edge contrast is improved.
Furthermore, the electron microscopic method according to the invention of the present application further includes the steps of: applying the liquid medium including an ionic liquid to an observation surface of the sample; and forming the liquid medium including an ionic liquid into a thin film. Generally, the film state of the applied liquid medium including an ionic liquid depends on the type of the ionic liquid and the material or shape of the sample. According to this method, the film thickness of the liquid medium including an ionic liquid can be controlled depending on the type of the ionic liquid or the sample.
Here, in the electron microscopic method according to the invention of the present application, an observation specimen is used that the liquid medium including an ionic liquid on the sample is in a thin film shape or in a mesh film shape.
Here, in the electron microscopic method according to the invention of the present application, the method may perform, for plural times, the steps of: applying the liquid medium including an ionic liquid to the observation surface of the sample; forming the liquid medium including an ionic liquid into a thin film; and measuring the film thickness of the liquid medium including an ionic liquid. According to this method, the liquid medium including an ionic liquid can be processed step by step until the liquid medium has a predetermined film thickness, so that the controllability of the film thickness of the liquid medium including an ionic liquid is improved.
Here, in the electron microscopic method according to the invention of the present application, the step of measuring the film thickness of the liquid medium including an ionic liquid may be the step of measuring the film thickness of the liquid medium including an ionic liquid from a primary electron acceleration voltage dependence of a secondary electron emission yield that is enabled to be analyzed using a pulsed primary electron. According to this method, the acceleration voltage at which a primary electron passes through the film of the liquid medium including an ionic liquid can be analyzed from a change in the secondary electron emission yield with respect to the acceleration voltage, and the film thickness of the liquid medium including an ionic liquid can be analyzed from the range of the primary electron at the acceleration voltage.
Here, in the electron microscopic method according to the invention of the present application, the step of measuring the film thickness of the liquid medium including an ionic liquid may be the step of measuring the film thickness of the liquid medium including an ionic liquid from a primary electron acceleration voltage dependence of a substrate current under the irradiation of primary electrons. Here, a displacement current that occurs due to electric charges stored when a primary electron passes to the sample is measured as a substrate current. According to this method, the acceleration voltage at which a primary electron passes through a film of the liquid medium including an ionic liquid can be analyzed by a change in the substrate current with respect to the acceleration voltage, and the film thickness of the liquid medium including an ionic liquid can be analyzed from the range of the primary electron at the acceleration voltage.
Moreover, an electron microscope according to the invention of the present application includes: an electron source configured to emit a primary electron; a sample holder configured to hold a sample; an exhaust chamber on which the sample holder is placed and configured to exhaust air; a lens system configured to focus the primary electron on the sample; a deflector configured to scan the primary electron; a detector configured to detect a secondary electron emitted from the sample by the primary electron; an image generating unit configured to form an image using the secondary electron; a sample chamber on which the sample holder is placed; a measuring mechanism configured to measure a film thickness of a liquid medium including an ionic liquid on the sample; and an irradiation condition control unit for the primary electron based on the film thickness of the liquid medium on the sample.
Here, in the electron microscope according to the invention of the present application, the measuring mechanism configured to measure a film thickness of the liquid medium including an ionic liquid may include: a pulse forming unit configured to form a pulse electron that the primary electron is pulsed; a secondary electron signal analyzing unit configured to analyze a secondary electron emission yield from a secondary electron signal that a secondary electron emitted from the sample by the pulse electron is detected at the detector; and a secondary electron emission yield analyzing unit configured to analyze an acceleration voltage at which the primary electron passes through a film of the liquid medium including an ionic liquid from an acceleration voltage dependence of the secondary electron emission yield and to analyze a film thickness from a range of the primary electron at the acceleration voltage.
Moreover, in the electron microscope according to the invention of the present application, the measuring mechanism configured to measure a film thickness of the liquid medium including an ionic liquid may include a substrate current measuring unit configured to measure a substrate current induced when the primary electron passes to the sample; and a substrate current analyzing unit configured to analyze an acceleration voltage at which the primary electron passes through a film of the liquid medium including an ionic liquid from an acceleration voltage dependence of the substrate current and to measure a film thickness from a range of the passing primary electron.
Here, in the electron microscope according to the invention of the present application, an applying unit configured to apply the liquid medium including an ionic liquid to an observation surface of the sample may be included on the sample holder or the sample chamber on which the sample is held.
Furthermore, in the electron microscope according to the invention of the present application, a mechanism configured to form the liquid medium including an ionic liquid on the sample into a thin film may be included on the sample holder or the sample chamber on which the sample is held.
In addition, an observation specimen preparation device that prepares the observation specimen according to the invention of the present application includes: an exhaust chamber; an exhaust mechanism; an applying unit configured to apply the liquid medium including an ionic liquid to an observation surface of a sample; a mechanism configured to form the liquid medium including an ionic liquid on the sample into a thin film; and a measuring mechanism configured to measure a film thickness of the liquid medium including an ionic liquid.
Here, the measuring mechanism configured to measure a film thickness of the liquid medium including an ionic liquid may include: an electron source configured to emit a primary electron; a substrate current measuring unit configured to measure a substrate current induced when the primary electron is irradiated to the sample; and a substrate current analyzing unit configured to analyze a primary electron acceleration voltage dependence of the substrate current.
Advantageous Effects of Invention
In accordance with the observation specimen, the electron microscopic method, the electron microscope, and the observation specimen preparation device according to the present invention, it is possible to suppress charging due to primary electrons, to obtain a clear edge contrast from the observation specimen, and to highly accurately measure a sample surface topology.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1A is a top view of an exemplary observation specimen according to a first embodiment of the present invention.
FIG. 1B is a cross sectional view of the exemplary observation specimen according to the first embodiment of the present invention.
FIG. 2A is a top view of an exemplary observation specimen according to a fifth embodiment of the present invention.
FIG. 2B is a cross sectional view of the exemplary observation specimen according to the fifth embodiment of the present invention.
FIG. 3A is an illustration of the presence or absence of a liquid medium including an ionic liquid on a sample.
FIG. 3B is a diagram of the time variations of secondary electron signals corresponding to the presence or absence of a liquid medium including an ionic liquid on a sample.
FIG. 4 is a block diagram of an exemplary electron microscope according to the first embodiment of the present invention.
FIG. 5A is an illustration of the cross sectional structures of observation specimens.
FIG. 5B is a diagram of SEM images of the observation specimens.
FIG. 5C is a diagram of the profiles of image lightness of the observation specimens.
FIG. 6 is a block diagram of an exemplary electron microscope according to a second embodiment of the present invention.
FIG. 7 is a diagram of an exemplary flowchart of an electron microscopic method according to the second embodiment of the present invention.
FIG. 8A is an illustration of the relationship between the acceleration voltage and range of primary electrons according to the second embodiment.
FIG. 8B is an illustration of the relationship between the acceleration voltage of primary electron and the substrate current according to the second embodiment.
FIG. 9A is a diagram of an SEM image obtained through an electron microscopic method according to the second embodiment.
FIG. 9B is an illustration of the profile of image lightness obtained through the electron microscopic method according to the second embodiment.
FIG. 10 is a block diagram of an exemplary observation specimen preparation device for an electron microscopic method according to a third embodiment of the present invention.
FIG. 11 is a diagram of an exemplary flowchart of an electron microscopic method according to the third embodiment of the present invention.
FIG. 12 is a block diagram of an exemplary electron microscope according to a fourth embodiment of the present invention.
FIG. 13 is a diagram of an exemplary flowchart of an electron microscopic method according to the fourth embodiment of the present invention.
FIG. 14 is an illustration of the relationship between the acceleration voltage of primary electrons and the secondary electron emission yield.
FIG. 15A is an illustration of the structure of an observation specimen for use in the fifth embodiment.
FIG. 15B is a diagram of the profile of image lightness of the observation specimen for use in the fifth embodiment.
FIG. 16 is a block diagram of an exemplary observation specimen preparation device for an electron microscopic method according to a sixth embodiment of the present invention.
FIG. 17 is a block diagram of an exemplary observation specimen preparation device for an electron microscopic method according to a seventh embodiment of the present invention.
FIG. 18 is a block diagram of an exemplary observation specimen preparation device for an electron microscopic method according to an eight embodiment of the present invention.
FIG. 19 is a diagram of an exemplary GUI for setting irradiation conditions for primary electrons according to the present invention.
DESCRIPTION OF EMBODIMENTS
In the following, embodiments of the present invention will be described with reference to the drawings. However, the embodiments are merely examples for implementing the present invention, which will not limit the technical scope of the present invention.
First Embodiment
FIG. 1A is a top view of an observation specimen that a liquid medium including an ionic liquid on a sample is in a thin film shape, and FIG. 1B is a cross sectional view of the observation specimen that the liquid medium including an ionic liquid is in a thin film shape. A sample 2 is a sample including groove patterns, and a liquid medium 3 including an ionic liquid is an ionic liquid in a thin film shape on the groove patterns. In the embodiment, an electron microscopic method will be described using the observation specimen that the liquid medium including an ionic liquid on the sample is in a thin film shape as illustrated in FIG. 1 . It is noted that the ionic liquid for use in the present invention is 1-Butyl-3-methylimidazolium Tetrafluoroborate, 1-Ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, and 1-Butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, for example. In the embodiment, a liquid medium including an ionic liquid was used in which the ionic liquid was diluted at 10% with pure water. In the embodiment, pure water was mixed in the ionic liquid. However, ethanol, methanol, acetone, and hexane, for example, may be mixed. Moreover, fine particles whose secondary electron emission yield is different from the secondary electron emission yield of the ionic liquid may be mixed in the ionic liquid in order to obtain a clear image contrast. The secondary electron emission yield means a rate that the number of secondary electrons emitted is divided by the number of primary electrons irradiated. The liquid medium including an ionic liquid means a liquid medium including an ionic liquid and a substance other than the ionic liquid. In the following, the ionic liquid refers to an ionic liquid or a liquid medium including an ionic liquid.
FIG. 5A is the cross sectional structures of observation specimens used in the embodiment. In the embodiment, the sample 2 is an SiO 2 sample having line groove patterns. The sample 2 to which an ionic liquid is not applied (A in FIG. 5A ), an observation specimen that an ionic liquid is dropped onto the sample 2 using a micropipet (B in FIG. 5A ), and an observation specimen that an ionic liquid on the sample 2 is in a thin film shape in which the ionic liquid is applied to the sample 2 using a dip coater (C in FIG. 5A ).
FIG. 4 is a block diagram of an electron microscope according to the embodiment. The electron microscope is configured of an electro-optical system, a stage system, a control system, an image processing system, a manipulation interface 27 , a sample chamber 32 , and an exhaust chamber 82 . The electro-optical system is configured of an electron source 10 , a condenser lens 11 , a diaphragm 12 , a deflector 13 , an objective lens 14 , and a detector 18 . The stage system is configured of a sample stage 15 , a sample holder 16 , and a sample 17 . The control system is configured of an electron source control unit 20 , a condenser lens control unit 21 , a deflection signal control unit 22 , a detector control unit 31 , and an SEM control unit 26 . The image processing system is configured of a detection signal processing unit 23 , an image generating unit 24 , and an image display unit 25 .
The irradiation conditions controlled in the embodiment are the acceleration voltage of primary electrons, an irradiation electric current, and a primary electron scanning speed. The acceleration voltage is controlled using a voltage applied to the electron source 10 by the electron source control unit 20 , and the irradiation electric current is controlled using an excitation current applied to the condenser lens 11 by the condenser lens control unit 21 . Moreover, the scanning speed is controlled by a deflection signal from the deflection signal control unit 22 to the deflector 13 .
FIG. 5B is SEM images acquired at an acceleration voltage of 1.0 kV, an irradiation electric current of 8 pA, and a primary electron scanning speed of 300 nm/μs. A in FIG. 5B is an SEM image of the sample 2 to which the ionic liquid is not applied, in which pattern portions become dark due to charging to cause shading. On the other hand, B in FIG. 5B is an SEM image of the observation specimen that the ionic liquid is dropped onto the sample 2 using the micropipet. In the case where the ionic liquid is applied using the micropipet, the ionic liquid does not take a thin film shape, and primary electrons are not enabled to pass through the ionic liquid, and thus it is not enabled to recognize patterns. C in FIG. 5B is an SEM image of the observation specimen that the ionic liquid on the sample 2 is in a thin film shape. Shading on pattern portions is suppressed, and patterns can also be recognized.
FIG. 5C is the profiles of image lightness analyzed in the direction across groove patterns. A portion showing the maximum image lightness corresponds to the edge portion of a groove. In A in FIG. 5C , the signal of the maximum portion corresponding to the edge portion is weak, and the edge contrast is small. Moreover, B in FIG. 5C , it is difficult to recognize the profile of the edge portion. On the other hand, in C in FIG. 5C , the signal of the maximum portion is strong, and a clear edge contrast is obtained. In accordance with the electron microscopic method according to the embodiment, it is possible to improve an edge contrast expressing the sample shape using the observation specimen that an ionic liquid on the sample is in a thin film shape.
Second Embodiment
In this embodiment, an electron microscopic method will be described in which the film thickness of an ionic liquid is measured and the irradiation conditions for the primary electrons are controlled based on the measured film thickness. In the embodiment, the observation specimen was used that the ionic liquid on the sample is in a thin film shape in C in FIG. 5A shown in the first embodiment.
In consideration of the film thickness of the ionic liquid and the range of low-energy primary electrons, the irradiation conditions for the primary electrons are controlled. Here, the range of electrons means the length of electrons passing through the inside of a substance. As described in a reference (K. Kanaya, S. Okayama, J. Phys. D. Appl. Phys. 5, 43 (1972)), a range R (μm) of the primary electrons is expressed by Equation 1.
R
=
0.0276
(
eV
)
5
/
3
A
ρ
8
/
9
Z
[
Equation
1
]
ρ (g/cm 3 ) is the density of a substance through which electrons pass, Z is an atomic number, A (g/mol) is an atomic weight, V (kV) is the acceleration voltage of the primary electrons, and e is an elementary electric charge. Equation 1 expresses that the range of the primary electrons depends on the acceleration voltage of the primary electrons as well as depends on the density of a substance and the atomic weight. Here, since the thickness of a single molecular layer of an ionic liquid depends on the density and molecular weight of the ionic liquid, the range of the primary electrons can be prescribed by a monolayer in a unit of the thickness of a single molecular layer (in the following, the thickness of a single molecular layer is referred to as a monolayer). It is important to adjust the acceleration voltage of the primary electrons based on the range of the primary electrons prescribed by a monolayer and the film thickness of the ionic liquid. Moreover, even in the case where the irradiation conditions are determined and the film thickness of the ionic liquid can be adjusted, it is important to adjust the film thickness of the ionic liquid in consideration of the range of the primary electrons.
The acceleration voltage of the primary electrons ranges from a voltage of 0.1 to 1.5 kV, for example. In the ionic liquid used in the embodiment, the acceleration voltage of the primary electrons passing through the film thickness of 100 monolayers is a voltage of 1.5 kV, and the acceleration voltage of the primary electrons passing through the film thickness of one monolayer is a voltage of 0.1 kV. In the estimation from the density, the molecular weight, and the composition, one monolayer of a typical ionic liquid was a thickness of 1 nm.
The film thickness of a portion to which the liquid medium including an ionic liquid is applied in the observation specimen is to be one monolayer or more and 100 monolayers or less, for example.
FIG. 3A is a sample 2 and an observation specimen that the ionic liquid on the sample 2 is in a thin film shape. In the embodiment, the sample 2 is an insulator. Moreover, FIG. 3B is the time variations of secondary electron signals emitted when low-energy primary electrons are irradiated to the sample 2 and the observation specimen that the ionic liquid on the sample 2 is in a thin film shape. As illustrated in B in FIG. 3B , when low-energy primary electrons are irradiated to the sample 2 , secondary electrons are emitted greater than the number of the primary electrons irradiated, and the sample surface is positively charged. At this time, since the amount of the secondary electrons emitted is reduced due to the positively charged surface, the secondary electron signal is attenuated immediately after the primary electrons are irradiated. On the other hand, as illustrated in A in FIG. 3A , in the observation specimen that the ionic liquid on the sample 2 is in a thin film shape, since charging in the irradiation region of the primary electrons is suppressed, the secondary electron signal is not attenuated under the irradiation of the primary electrons, and takes a constant value. Thus, even in the case where the ionic liquid is in a thin film shape, it is shown that the effect of suppressing charging is exerted.
A, B, and C in FIGS. 5B and 5C are images and the profiles of image lightness in which the sample 2 with patterns, the observation specimen including an ionic liquid on the sample 2 , and the observation specimen that the ionic liquid on the sample 2 is in a thin film shape are observed using low-energy primary electrons. As illustrated in A in FIG. 5B , when no ionic liquid is present, the pattern portion is in a low contrast due to the charged surface. As illustrated in B in FIG. 5B , when the ionic liquid is not a thin film, the pattern portion is filled with the ionic liquid, and the edge contrast is eliminated. As illustrated in C in FIG. 5B , when the ionic liquid is in a thin film shape, a high contrast is obtained from the pattern portion. Moreover, as illustrated in A in FIG. 5C , when no ionic liquid is present, the signal of the edge portion is reduced due to the charged sample, and the profile of image lightness is in asymmetry. On the other hand, as illustrated in C in FIG. 5C , when the ionic liquid is in a thin film shape, the profile of image lightness is in symmetry, and such a contrast is obtained in which the edge portion of the sample 2 is more highlighted. When the observation specimen includes an ionic liquid in a thin film shape on the sample, the edge contrast of the sample 2 is obtained even using low-energy electrons while the effect of suppressing charging is provided.
FIG. 6 is a block diagram of an electron microscope according to the embodiment. The electron microscope is configured of an electro-optical system, a stage system, a control system, an image processing system, a manipulation interface 27 , a sample chamber 32 , an exhaust chamber 82 , and a substrate current measurement system. The substrate current is an electric current carried from the observation specimen to the stage system (a sample holder 16 ) by irradiating primary electrons. The electro-optical system is configured of an electron source 10 , a condenser lens 11 , a diaphragm 12 , a deflector 13 , an objective lens 14 , and a detector 18 . The stage system is configured of a sample stage 15 , the sample holder 16 , and a sample 17 . The control system is configured of an electron source control unit 20 , a condenser lens control unit 21 , a deflection signal control unit 22 , a detector control unit 31 , and an SEM control unit 26 . The image processing system is configured of a detection signal processing unit 23 , an image generating unit 24 , and an image display unit 25 . The substrate current measurement system is configured of an ammeter 28 and a substrate current analyzing unit 29 .
FIG. 7 is a flowchart of the electron microscopic method. The electron microscopic method according to the embodiment will be described with reference to the flowchart in FIG. 7 . First, the film thickness of the ionic liquid of the observation specimen is measured (Step 42 ). In the embodiment, a substrate current was measured under the irradiation of the primary electrons using the electron microscope illustrated in FIG. 6 , and the film thickness of the ionic liquid was analyzed. Here, a displacement current induced by electric charges stored on the sample under the irradiation of the primary electrons can be measured as a substrate current. First, the electron source control unit 20 controls the acceleration voltage of the primary electrons using the voltage applied to the electron source 10 , and changes the acceleration voltage, and substrate currents at the individual acceleration voltages are measured at the ammeter 28 . FIG. 8 A is a schematic diagram of the relationship between the acceleration voltage and range of the primary electrons. When the acceleration voltage of the primary electrons is increased as in A, B, and C, the range of a primary electron 5 is increased. When the range of the primary electron is the film thickness of a liquid medium 3 including an ionic liquid or more (C in FIG. 8A ), the primary electron reaches the sample 2 , and electric charges are stored on the sample. At this time, a displacement current occurs due to stored charges, and can be measured as a substrate current. FIG. 8B is changes in the substrate current when the acceleration voltage of the primary electrons is changed from a voltage of 0.1 kV to a voltage of 1.5 kV. It is shown from FIG. 8B that the substrate current is suddenly increased at an acceleration voltage of 1.0 kV. The acceleration voltage when this substrate current is suddenly increased is an acceleration voltage at which the primary electron passes through the film thickness. As a result that the range is analyzed by Equation 1, since the range at an acceleration voltage of 1.0 kV is 60 monolayers, the film thickness of the ionic liquid is 60 monolayers. The process step of analyzing the acceleration voltage dependence of the substrate current described in the embodiment is processed at the substrate current analyzing unit 29 , and the film thickness can be automatically obtained.
Next, the irradiation conditions for the primary electrons are controlled based on the film thickness with reference to the flowchart in FIG. 7 (Step 43 ). In the embodiment, in order to detect secondary electrons from the sample, the acceleration voltage was controlled at a voltage of 1.2 kV in such a way that the range of the primary electrons is longer than 60 monolayers. At this time, the primary electrons pass through the ionic liquid thin film, and reach the sample. Thus, in order to restrict the number of electrons irradiated to the sample in consideration of the sample damage, the irradiation electric current was controlled at 5 pA, and the scanning speed was controlled at 300 nm/μs.
Lastly, an image is acquired under the set irradiation conditions for the primary electrons based on the flowchart in FIG. 7 , and the image is displayed on the image display unit 25 (Step 44 ).
FIG. 19 is a graphical user interface (in the following, referred to as a GUI) that sets the irradiation conditions for the primary electrons according to the embodiment. The GUI in FIG. 19 is displayed on the monitor of the manipulation interface 27 . On a window 130 , information about a sample and an ionic liquid inputted to the SEM control unit 26 are displayed. On a window 131 , the acceleration voltage dependence of the substrate current of the observation specimen and the film thickness of the ionic liquid are displayed. On a window 132 , the irradiation conditions for the primary electrons corresponding to the film thickness of the ionic liquid are displayed.
FIG. 9A is an image obtained by observing the observation specimen, and FIG. 9B is the profile of image lightness analyzed in the direction across groove patterns according to the embodiment. The maximum value of image lightness expressing the edge portion of the pattern is great, and a clear edge contrast can be obtained. In accordance with the electron microscopic method according to the embodiment, the film thickness of the ionic liquid thin film is measured, and the optimum irradiation conditions can be set, so that it is possible to improve an edge contrast expressing the sample shape.
Third Embodiment
In the embodiment, an electron microscopic method will be described using an observation specimen in which an ionic liquid is applied to a sample and then formed into a thin film. In the embodiment, a resist sample having line groove patterns was used.
FIG. 10 is a block diagram of an observation specimen preparation device for an electron microscopic method according to the embodiment. Here, the observation specimen preparation device is a device that applies an ionic liquid to a sample and prepares an observation specimen, including an ionic liquid adjusting unit 72 that mixes an ionic liquid with a substance different from the ionic liquid, an ionic liquid discharging unit 73 , a sample 74 , a sample holder 75 , a sample holding unit 76 , a sample holding unit rotating mechanism 77 , a valve 80 , an exhaust mechanism 81 , an exhaust chamber 82 , and a control system. The control system is configured of an ionic liquid adjustment control unit 84 , a discharge control unit 85 , a rotation control unit 86 , and an exhaust control unit 87 . Although the observation specimen preparation device for an electron microscopic method is a part of an electron microscope, the device may be independent of the electron microscope. An electron microscope according to the embodiment is in the configuration similar to FIG. 4 .
FIG. 11 is a flowchart of the electron microscopic method. The electron microscopic method according to the embodiment will be described with reference to the flowchart in FIG. 11 . First, an ionic liquid is applied to the sample 74 (Step 52 ). In the embodiment, the ionic liquid was applied using the observation specimen preparation device in FIG. 10 . First, an ionic liquid adjusted at the ionic liquid adjusting unit 72 is controlled by the discharge control unit 85 and discharged from the discharging unit 73 , and the ionic liquid is applied to the sample 74 . In the embodiment, pure water was mixed in the ionic liquid as a solvent, and the ionic liquid whose viscosity was 20 mPa·s was discharged onto the sample.
Subsequently, based on the flowchart in FIG. 11 , the applied ionic liquid is formed into a thin film (Step 53 ). In the embodiment, the ionic liquid was formed into a thin film using the observation specimen preparation device in FIG. 10 by rotating the sample holding unit 76 using the sample holding unit rotating mechanism 77 . The rotation control unit 86 controlled the rotation speed and rotation time in such a way that the sample holding unit 76 was rotated at 500 rpm for 10 seconds and then rotated at 3,000 rpm for 60 seconds. Subsequently, the sample 74 was put into the exhaust chamber 82 for vacuum exhaust. When the ionic liquid includes a substance that is vaporized under a vacuum, the substance that is vaporized under a vacuum is vaporized by vacuum exhaust, so that the ionic liquid can be formed into a thin film. In the embodiment, vacuum exhaust was performed until the pressure of the exhaust chamber 82 reached a pressure of 1×10 −4 Pa, which is almost the same vacuum degree in electron microscopic observation. Here, in the embodiment, the ionic liquid is applied and then vacuum exhaust is performed. However, it may be fine that an ionic liquid is applied under a vacuum and the process of forming a thin film is performed.
Lastly, based on the flowchart in FIG. 11 , an image of the observation specimen is acquired (Step 54 ). In the embodiment, the acceleration voltage of the primary electrons is a voltage of 0.1 kV, the electric current is 5 pA, and the scanning speed is 200 nm/μs.
The image obtained by observing the prepared observation specimen according to the embodiment is similar to the image in C in FIG. 5B , and the profile of image lightness analyzed in the direction across groove patterns is similar to the profile in C in FIG. 5C . The maximum value of image lightness expressing the edge portion of the pattern is great, and a clear edge contrast can be obtained. In accordance with the electron microscopic method according to the embodiment, the film thickness of the ionic liquid thin film can be controlled, and the image can be acquired, so that it is possible to improve an edge contrast expressing the sample shape.
Fourth Embodiment
In the embodiment, an electron microscopic method will be described in which the irradiation conditions for the primary electrons are set, it is determined whether the film thickness is an appropriate film thickness to the set irradiation conditions for the primary electrons, and then an image is acquired. In the embodiment, the observation specimen described in the third embodiment was used.
FIG. 12 is a block diagram of an electron microscope according to the embodiment. The electron microscope is configured of an electro-optical system, a stage system, a control system, an image processing system, a manipulation interface 27 , a sample chamber 32 , and an exhaust chamber 82 . The electro-optical system is configured of an electron source 10 , a condenser lens 11 , a diaphragm 12 , a deflector 13 , an objective lens 14 , a detector 18 , and a pulse forming unit 19 . The stage system is configured of a sample stage 15 , a sample holder 16 , and a sample 17 . The control system is configured of an electron source control unit 20 , a condenser lens control unit 21 , a deflection signal control unit 22 , a detector control unit 31 , an SEM control unit 26 , and a pulse control unit 30 . The image processing system is configured of a detection signal processing unit 23 , an image generating unit 24 , and an image display unit 25 .
FIG. 13 is a flowchart of the electron microscopic method. The electron microscopic method according to the embodiment will be described with reference to the flowchart in FIG. 13 . First, the irradiation conditions for the primary electrons are set (Step 62 ). In the embodiment, the electron microscopic method is performed using the electron microscope in FIG. 12 . Here, the irradiation condition for the primary electrons was an acceleration voltage of 0.3 kV at which the secondary electron emission yield is high. In the embodiment, in order to prevent the sample from being damaged due to the direct irradiation of the primary electrons to a resist, a thin film is formed in such a way that the film thickness of an ionic liquid is thicker than the range of the primary electrons at a voltage of 0.3 keV and the ionic liquid film reflects the sample surface topology. Here, since the primary electrons do not pass through the ionic liquid film, the irradiation conditions for the primary electrons were controlled in which the irradiation electric current was 20 pA and the scanning speed was 100 nm/μs at which the SN ratio of an image is high.
Subsequently, the film thickness of the ionic liquid of the observation specimen was measured based on the flowchart in FIG. 13 (Step 65 ). The observation specimen used in the embodiment is the observation specimen described in the third embodiment. In the embodiment, the film thickness of the ionic liquid was analyzed by measuring the secondary electron emission yield using pulse electrons with the electron microscope in FIG. 12 . Here, a method for measuring the secondary electron emission yield will be described. When low-energy primary electrons are irradiated, the insulator is positively charged, and the number of the secondary electrons to be emitted is reduced. When the number of the primary electrons irradiated is matched with the number of the secondary electrons emitted, the secondary electron emission yield becomes one in the stationary state. In other words, the secondary electron emission yield of one corresponds to the strength of the secondary electron signal in which the pulse electrons formed at the pulse forming unit 19 are irradiated and secondary electrons detected at the detector 18 are reduced under the irradiation of the primary electrons and become stationary. The strength of the secondary electron signal when the primary electrons are irradiated is divided by the strength of the secondary electron signal in the stationary state, and the secondary electron emission yield is obtained.
FIG. 14 is the acceleration voltage dependence of the secondary electron emission yield of the observation specimen used in the embodiment. In the embodiment, since it is necessary to compare the secondary electron emission yield of the ionic liquid with the secondary electron emission yield of the resist, the acceleration voltage dependences of the secondary electron emission yields of the ionic liquid and the resist were complied into a database. FIG. 14 is the secondary electron emission yield of the observation specimen as well as the acceleration voltage dependence of a secondary electron emission yield 91 of the resist and the acceleration voltage dependence of a secondary electron emission yield 92 of the ionic liquid called from the database. The secondary electron emission yield of the observation specimen was matched with the acceleration voltage dependence of the secondary electron emission yield 92 of the ionic liquid at an acceleration voltage of 0.8 kV or less, and was almost matched with the acceleration voltage dependence of the secondary electron emission yield 91 of the resist at an acceleration voltage of 1.5 kV or more. On the other hand, at the acceleration voltage ranging from a voltage of 0.8 kV to a voltage of 1.5 kV, the secondary electron emission yield of the observation specimen takes the median value between the acceleration voltage dependence of the secondary electron emission yield 92 of the ionic liquid and the acceleration voltage dependence of the secondary electron emission yield 91 of the resist. Thus, it can be determined from FIG. 14 that the ionic liquid is passed at an acceleration voltage of 0.8 kV. As a result that the range was analyzed from Equation 1, since the range at an acceleration voltage of 0.8 kV is 50 monolayers, the film thickness of the ionic liquid is 50 monolayers. Here, in the ionic liquid used in the embodiment, the thickness of one monolayer is 0.5 nm.
Subsequently, it was determined whether the film thickness of the ionic liquid is appropriate based on the flowchart in FIG. 13 (Step 66 ). Since the range at a voltage of 0.3 kV, which is the acceleration voltage according to the embodiment, is 20 monolayers, and is the film thickness (50 monolayers) measured in the embodiment or less, it was determined that the film thickness is appropriate. Here, in the case where the film thickness is thinner than 20 monolayers, the ionic liquid is again applied, the ionic liquid is processed into a thin film, the film thickness is measured (Steps 63 , 64 , and 65 ), and the processes are repeated until a predetermined film thickness is obtained.
Lastly, based on the flowchart in FIG. 13 , an image is acquired under the set irradiation condition for the primary electrons, and the image is displayed on the image display unit 25 (Step 67 ).
An image obtained by observing the prepared observation specimen according to the embodiment is similar to FIG. 9A , and the profile of image lightness analyzed in the direction across groove patterns is similar to FIG. 9B . The maximum value of image lightness expressing the edge portion of the pattern is great, and a clear edge contrast can be obtained. In accordance with the electron microscopic method according to the embodiment, the film thickness of the ionic liquid thin film can be highly accurately controlled, so that the edge contrast reflecting the sample shape can be improved.
Fifth Embodiment
FIG. 2A is a top view of an observation specimen that an ionic liquid is in a mesh film shape, and FIG. 2B is a cross sectional view of the observation specimen that the ionic liquid is in a mesh film shape. In this embodiment, an electron microscopic method will be described using an observation specimen that an ionic liquid is in a mesh film shape as illustrated in FIG. 2 . In the embodiment, the configuration of the electron microscope illustrated in FIG. 12 was used. Moreover, in the embodiment, an SiO 2 sample having groove patterns of different pitches and sizes wads used. A hydrophobic ionic liquid was used, and was applied to the sample pattern surface using a dip coater. Since the wettability between the ionic liquid and the sample is varied depending on the pattern pitch and pattern size of the sample, the state of an ionic liquid film is different for individual patterns.
FIG. 15A is the structure of the observation specimen used in the embodiment. As illustrated in FIG. 15A , in the observation specimen, the state of an ionic liquid film is varied depending on the pattern pitch and pattern size of the sample. FIG. 15B is the profile of image lightness analyzed in the direction across groove patterns of an SEM image of this observation specimen acquired at an acceleration voltage of 1.0 kV, an irradiation electric current of 8 pA, and a scanning speed of 300 nm/μs. As illustrated in FIG. 15B , contrasts are observed corresponding to the pattern pitch and pattern size of the sample. In accordance with the electron microscopic method according to the embodiment, it is possible to highly accurately measure the sample shape from the observation specimen including an ionic liquid.
Sixth Embodiment
In this embodiment, an observation specimen preparation device for an electron microscopic method will be described, which is in another configuration different from the method described in the third embodiment.
FIG. 16 is a block diagram of an observation specimen preparation device for an electron microscopic method according to the embodiment. The observation specimen preparation device for an electron microscopic method is configured of a sample 101 , a sample supporting unit 102 that supports a sample, a drive unit 103 that freely moves up and down the sample supporting unit 102 , the drive control unit 104 that controls the position and the rate of travel of the sample supporting unit 102 , an ionic liquid adjusting unit 106 that fills an ionic liquid or an ionic liquid 105 mixed with a substance other than the ionic liquid in a liquid bath 108 , and an ionic liquid adjustment control unit 107 that controls the adjustment of the ionic liquid or the ionic liquid 105 mixed with a substance other than the ionic liquid. It is noted that the configuration of the observation specimen preparation device for an electron microscopic method may be a configuration in which the device is installed on the sample chamber or the exhaust chamber of an electron microscope.
A method for applying an ionic liquid according to the embodiment will be described. In the embodiment, the sample 101 is an SiO 2 sample having line groove patterns, and the ionic liquid 105 is 1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide containing 95% of pure water. First, the sample 101 is supported on the sample supporting unit 102 , the sample supporting unit 102 is lowered, and the sample 101 is put into the liquid bath 108 filled with the ionic liquid adjusted by the ionic liquid adjusting unit 106 beforehand. Subsequently, the sample supporting unit 102 is pulled up while controlling the rate of travel of the drive unit 103 by the drive control unit 104 , and the ionic liquid 105 is applied to the sample 101 . The rate of travel of the drive unit 103 is controlled, so that the film thickness of the ionic liquid 105 can be controlled. In the embodiment, the velocity of pulling up the sample supporting unit 102 from the liquid bath 108 was controlled at 5 cm/min, and the ionic liquid 105 was applied over the thin film. After that, the sample 101 was placed in the exhaust chamber for air purge. Pure water contained in the ionic liquid is vaporized by air purge, and the ionic liquid can be formed into a thin film. In the embodiment, vacuum exhaust was performed until the pressure of the exhaust chamber reached a pressure of 2×10 −2 Pa. It was shown that the film thickness of the ionic liquid 105 formed on the sample 101 was 100 monolayers by the method for measuring the film thickness according to the second embodiment. With the use of the observation specimen preparation device for an electron microscopic method according to the embodiment, it is possible to highly accurately control the film thickness of the ionic liquid on the sample.
Seventh Embodiment
In this embodiment, an observation specimen preparation device for an electron microscopic method will be described, which is in another configuration different from the method described in the third embodiment.
FIG. 17 is a block diagram of an observation specimen preparation device for an electron microscopic method according to the embodiment. The observation specimen preparation device for an electron microscopic method is configured of a sample 111 , a sample supporting unit 112 that supports the sample 111 , a heater 113 , a temperature control unit 114 , an ionic liquid film 115 , a film supporting unit 116 that supports the ionic liquid film 115 , a drive unit 117 that moves the film supporting unit 116 , and a drive control unit 118 . Here, the ionic liquid film is an ionic liquid in a plate shape or film shape. It is noted that the configuration of the observation specimen preparation device for an electron microscopic method may be a configuration in which the device is installed on the sample holder, the sample chamber, or the exhaust chamber of an electron microscope.
A method for applying an ionic liquid according to the embodiment will be described. In the embodiment, the sample 111 is an SiO 2 sample having line groove patterns. First, the sample 111 is supported on the sample supporting unit 112 , the film supporting unit 116 is lowered while controlling the rate of travel of the drive unit 117 by the drive control unit 118 , and the ionic liquid film 115 is brought into intimate contact with the sample 111 . The temperature of the heater 113 is controlled by the temperature control unit 114 according to the type of the sample 111 and the type of the ionic liquid film 115 , and an ionic liquid is applied to the sample 111 . Since the viscosity of the ionic liquid is reduced at high temperature, the ionic liquid can be applied to the sample. In the embodiment, the temperature of the heater was controlled at a temperature of 60° C., and the ionic liquid was applied to the sample 111 while bringing the ionic liquid film 115 into intimate contact with the sample ill. It was shown by the method for measuring the film thickness according to the second embodiment that the film thickness of the formed ionic liquid on the sample 111 was one monolayer. With the use of the observation specimen preparation device for an electron microscopic method according to the embodiment, it is possible to highly accurately control the film thickness of the ionic liquid of the observation specimen by controlling the temperature of the heater.
Eighth Embodiment
In the embodiment, an observation specimen preparation device for an electron microscopic method will be described, which is in another configuration different from the method described in the third embodiment. In the embodiment, FIG. 18 is a block diagram of an observation specimen preparation device for an electron microscopic method according to the embodiment. The observation specimen preparation device for an electron microscopic method is configured of a sample 121 , a sample supporting unit 122 that supports the sample, an ozone application source 123 , an ozone application source control unit 124 , an ionic liquid discharging unit 125 , a discharge control unit 126 , a driving mechanism 127 that moves the ionic liquid discharging unit 125 , a drive control unit 128 that controls the position and rate of travel of the ionic liquid discharging unit 125 , an ionic liquid adjusting unit 129 that mixes an ionic liquid with a substance other than the ionic liquid, an ionic liquid adjustment control unit 140 that controls the adjustment of the ionic liquid, a valve 141 , an exhaust mechanism 142 , an exhaust chamber 143 , an exhaust control unit 144 , a heater 145 , and a temperature control unit 146 . It is noted that the configuration of the observation specimen preparation device for an electron microscopic method may be a configuration in which the device is installed on the sample chamber or the exhaust chamber of an electron microscope.
A method for applying an ionic liquid according to the embodiment will be described. First, an ionic liquid or an ionic liquid mixed with a substance other than the ionic liquid at the ionic liquid adjusting unit 129 beforehand is prepared according to the sample 121 . In the embodiment, since the sample 121 is an SiO 2 sample having line groove patterns, pure water was mixed in 1-Butyl-3-methylimidazolium Tetrafluoroborate to prepare a concentration of 1%. Subsequently, the application conditions for the ozone application source 123 are controlled by the ozone application source control unit 124 depending on the types of the sample 121 and the ionic liquid, and ozone is applied to the sample 121 supported on the sample supporting unit 122 . Since the applied ozone improves the surface state on the sample 121 , the wettability to the liquid is changed. In the embodiment, ozone was applied to the sample 121 for a second. After that, the amount of the ionic liquid discharged is controlled by the discharge control unit 126 , and the ionic liquid is applied. In the embodiment, the ionic liquid was discharged by an ink jet method. Moreover, in order to prevent the solvent of the ionic liquid at one-percent concentration from being vaporized due to heat before discharging, the ionic liquid was discharged by a piezo method, not by a thermal method. The amount of the ionic liquid discharged per discharge depends on the nozzle diameter and the applied voltage, and can be controlled in the range of femtoliter to microlitter. In the embodiment, the amount per discharge was set to two picoliters. Since the ionic liquid was coagulated in association with vaporization of the solvent when the number of discharges was 1,000 times or more, the number of discharges per place was set to 500 times. After that, similarly, the driving mechanism 127 is controlled by the drive control unit 128 , the ionic liquid discharging unit 125 is moved, and the ionic liquid is applied. When the ionic liquid is applied or after the ionic liquid is applied, the temperature of the heater 145 is controlled by the temperature control unit 146 , and the temperature of the sample 121 is adjusted depending on the type of the sample, the type of the ionic liquid, and the amount of discharge. The temperature of the sample 121 is adjusted to change the wettability between the sample and the ionic liquid, so that it is possible to form a state in which the form of the ionic liquid to be applied is advantageous to form a thin film. In the embodiment, the temperature of the sample 121 was set at a temperature of 40° C. when the ionic liquid was applied. After that, the exhaust mechanism 142 is controlled by the exhaust control unit 144 , and the exhaust chamber 143 is subjected to vacuum exhaust. When the ionic liquid contains a substance that is vaporized under a vacuum, the substance that is vaporized under a vacuum is vaporized by vacuum exhaust, so that the ionic liquid can be formed into a thin film. In the embodiment, vacuum exhaust was performed until the pressure of the exhaust chamber 143 reached a pressure of 1×10 −4 Pa, which is almost the same vacuum degree in electron microscopic observation, and pure water was vaporized. With the use of the observation specimen preparation device for an electron microscopic method according to the embodiment, it is possible to highly accurately control the film thickness of the ionic liquid of the observation specimen by controlling the ozone application conditions, the adjustment of the ionic liquid, the control of the amount of the ionic liquid discharged, the temperature control of the sample, and the control of air purge. It is noted that in the embodiment, ozone is applied. However, ultraviolet rays or plasma may be applied.
REFERENCE SIGNS LIST
2 Sample
3 Liquid medium including an ionic liquid
5 Primary electron
6 Region to which a primary electron reaches
10 Electron source
11 Condenser lens
12 Diaphragm
13 Deflector
14 Objective lens
15 Sample stage
16 Sample holder
17 Sample
18 Detector
19 Pulse forming unit
20 Electron source control unit
21 Condenser lens control unit
22 Deflection signal control unit
23 Detection signal processing unit
24 Image generating unit
25 Image display unit
26 SEM control unit
27 Manipulation interface
28 Ammeter
29 Substrate current analyzing unit
30 Pulse control unit
31 Detector control unit
32 Sample chamber
72 Ionic liquid adjusting unit
73 Ionic liquid discharging unit
74 Sample
75 Sample holder
76 Sample holding unit
77 Sample holding unit rotating mechanism
80 Valve
81 Exhaust mechanism
82 Exhaust chamber
84 Ionic liquid adjustment control unit
85 Discharge control unit
86 Rotation control unit
87 Exhaust control unit
91 Acceleration voltage dependence of the secondary electron emission yield of a resist
92 Acceleration voltage dependence of the secondary electron emission yield of an ionic liquid
101 Sample
102 Sample supporting unit
103 Drive unit
104 Drive control unit
105 Ionic liquid or ionic liquid mixed with a substance other than the ionic liquid
106 Ionic liquid adjusting unit
107 Ionic liquid adjustment control unit
108 Liquid bath
111 Sample
112 Sample supporting unit
113 Heater
114 Temperature control unit
115 Ionic liquid film
116 Film supporting unit
117 Drive unit
118 Drive control unit
121 Sample
122 Sample supporting unit
123 Ozone application source
124 Ozone application source control unit
125 Ionic liquid discharging unit
126 Discharge control unit
127 Driving mechanism
128 Drive control unit
129 Ionic liquid adjusting unit
130 , 131 , 132 Window
140 Ionic liquid adjustment control unit
141 Valve
142 Exhaust mechanism
143 Exhaust chamber
144 Exhaust control unit
145 Heater
146 Temperature control unit
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The electrical charging by a primary electronic is inhibited to produce a clear edge contrast from an observation specimen (i.e., a specimen to be observed), whereby the shape of the surface of a sample can be measured with high accuracy. An observation specimen in which a liquid medium comprising an ionic liquid is formed in a thin-film-like or a webbing-film-like form on a sample is used. An electron microscopy using the observation specimen comprises: a step of measuring the thickness of a liquid medium comprising an ionic liquid on a sample; a step of controlling the conditions for irradiation with a primary electron on the basis of the thickness of the liquid medium comprising the ionic liquid; and a step of irradiating the sample with the primary electron under the above-mentioned primary electron irradiation conditions to form an image of the shape of the sample.
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CROSS REFERENCE TO RELATED APPLICATION
The present application is a continuation-in-part of U.S. application No. 08/804,166, filed Feb. 20, 1997, which claims the benefit of U.S. Provisional Application no. 60/011,936, filed Feb. 20, 1996, the entire contents of application Nos. 08/804,166 and 60/011,936 are hereby incorporated by reference.
FIELD OF THE INVENTION
The present invention relates to a hybrid protein comprising two coexpressed amino acid sequences forming a dimer, each comprising:
a) at least one amino acid sequence selected from a homomeric receptor, a chain of a heteromeric receptor, a ligand, and fragments thereof; and
b) a subunit of a heterodimeric proteinaceous hormone or fragments thereof; in which (a) and (b) are bonded directly or through a peptide linker, and, in each couple, the two subunits (b) are different and capable of aggregating to form a dimer complex.
BACKGROUND OF THE INVENTION
Protein-protein interactions are essential to the normal physiological functions of cells and multicellular organisms. Many proteins in nature exhibit novel or optimal functions when complexed with one or more other protein chains. This is illustrated by various ligand-receptor combinations that contribute to regulation of cellular activity. Certain ligands, such as tumor necrosis factor α (TNFα), TNFβ, or human chorionic gonadotropin (hCG), occur as multi-subunit complexes. Some of these complexes contain multiple copies of the same subunit. TNFα and TNFβ (collectively referred to hereafter as TNF) are homotrimers formed by three identical subunits (1-4). Other ligands are composed of non-identical subunits. For example, hCG is a heterodimer (5-7). Receptors may also occur or function as multi-chain complexes. For example, receptors for TNF transduce a signal after being aggregated to form dimers (8,9). Ligands to these receptors promote aggregation of two or three receptor chains, thereby affording a mechanism of receptor activation. For example, TNF-mediated aggregation activates TNF receptors (10-12).
The modulation of protein-protein interactions can be a useful mechanism for therapeutic intervention in various diseases and pathologies. Soluble binding proteins, that can interact with ligands, can potentially sequester the ligand away from the receptor, thereby reducing the activation of that particular receptor pathway. Alternatively, sequestration of the ligand may delay its elimination or degradation, thereby increasing its duration of effect, and perhaps its apparent activity in vivo. In the case of TNF, soluble TNF receptors have been primarily associated with inhibition of TNF activity (13-17).
Soluble binding proteins may be useful for treating human diseases. For example, soluble TNF receptors have been shown to have efficacy in animal models of arthritis (18,19).
Since TNF has three binding sites for its receptor (10-12), and dimerization of the cell surface receptor is sufficient for bioactivity (8,9), it is likely that binding of a single soluble receptor to TNF will leave open the possibility that this 1:3 complex of soluble receptor:TNF (trimer) can still bind and activate a pair of cell surface TNF receptors. To achieve an inhibitory effect, it would be expected that two of the receptor binding sites on the TNF trimer must be occupied or blocked by the soluble binding protein. Alternatively, the binding protein could block proper orientation of TNF at the cell surface.
Generally speaking, the need was felt of synthesizing proteins that contain two receptor (or ligands) chains, as dimeric hybrid protein. See Wallach et al., U.S. Pat. No. 5,478,925.
The primary strategy employed for generating dimeric or multimeric hybrid proteins, containing binding domains from extracellular receptors, has been to fuse these proteins to the constant regions of an antibody heavy chain.
This strategy led, for example, to the construction of CD4 immunoadhesins (20). These are hybrid molecules consisting of the first two (or all four) immunoglobulin-like domains of CD4 fused to the constant region of antibody heavy and light chains. This strategy for creating hybrid molecules was adapted to the receptors for TNF (10,16,21) and led to the generation of constructs with higher in vitro activity than the monomeric soluble binding proteins.
It is widely held that the higher in vitro potency of the dimeric fusion proteins should translate into higher in vivo activity. One study does support this, revealing an at least 50-fold higher activity for a p75(TBP2)-Ig fusion protein in protecting mice from the consequences of intravenous LPS injection (16).
However, despite the widespread utilization of immunoglobulin fusion proteins, this strategy has several drawbacks. One is that certain immunoglobulin Fc domains participate in effector functions of the immune system. These functions may be undesirable in a particular therapeutic setting (22).
A second limitation pertains to the special cases where it is desirable to produce heteromeric fusion proteins, for example soluble analogs of the heteromeric IL-6 or type I interferon receptors. Although there are numerous methods for producing bifunctional antibodies (e.g., by co-transfection or hybridoma fusions), the efficiency of synthesis is greatly compromised by the mixture of homodimers and heterodimers that typically results (23). Recently there have been several reports describing the use of leucine zipper motifs to guide assembly of heterodimers (24-26). This appears to be a promising approach for research purposes, but the non-native or intracellular sequences employed may not be suitable for chronic applications in the clinic due to antigenicity. The efficiency of assembly and stability post assembly may also be limitations.
On the other hand, in the particular case of TNF receptors, certain modifications to the p55 TNF receptor have been found to facilitate homodimerization and signaling in the absence of ligand (27,28). It has been found that a cytoplasmic region of the receptor, termed the “death domain,” can act as a homodimerization motif (28,30). As an alternative to an immunoglobulin hybrid protein, fusion of the extracellular domain of the TNF receptor to its cytoplasmic death domain could conceivably result in a secreted protein which can dimerize in the absence of TNF. Such fusion proteins have been disclosed and claimed in the International Patent Application WO 95/31544.
A third further strategy employed for generating dimers of soluble TNF receptors has been to chemically cross-link the monomeric proteins with polyethylene glycol (31).
SUMMARY OF THE INVENTION
An alternative for obtaining such dimeric proteins, offering some important advantages, is the one of the present invention and consists in using a natural heterodimeric scaffold corresponding to a circulating non-immunoglobulin protein with a long half-life. A preferred example is hCG, a protein that is secreted well, has good stability, and has a long half-life (32-33). Given hCG's prominent role as a marker of pregnancy, many reagents have been developed to quantitate and study the protein in vitro and in vivo . In addition, hCG has been extensively studied using mutagenesis, and. it is known that small deletions to the protein, such as removal of five residues at the extreme carboxyl-terminus of the a subunit, can effectively eliminate its biological activity while preserving its capability to form heterodimer (34,35). Small insertions, of up to 30 amino acids, have been shown to be tolerated at the amino- and carboxyl-termini of the α subunit (36), while fusion of the α subunit to the carboxyl terminus of the β subunit also had little effect on heterodimer formation (37).
An analog of hCG in which an immunoglobulin Fc domain was fused to the C-terminus of hCG β subunit has also been reported; however, this construct was not secreted and no effort was made to combine it with an α subunit (38).
Therefore, the main object of the present invention is a hybrid protein comprising two coexpressed amino acid sequences forming a dimer, each comprising:
a) at least one amino acid sequence selected among a homomeric receptor, a chain of a heteromeric receptor, a ligand, and fragments thereof; and
b) a subunit of a heterodimeric proteinaceous hormone, or fragments thereof; in which (a) and (b) are bonded directly or through a peptide linker, and in each couple the two subunits (b) are different and capable of aggregating forming a dimer complex.
According to the present invention, the linker may be enzymatically cleavable.
Sequence (a) is preferably selected among: the extracellular domain of the TNF Receptor 1 (55 kDa, also called TBP1), the extracellular domain of the TNF Receptor 2 (75 kDa, also called TBP2), or fragments thereof still containing the ligand binding domain; the extracellular domains of the IL-6 receptors (also called gp80 and gp130); the extracellular domain of the IFN α/β receptor or IFN γ receptor; a gonadotropin receptor or its extracellular fragments; antibody light chains, or fragments thereof, optionally associated with the respective heavy chains; antibody heavy chains, or fragments thereof, optionally associated with the respective light chains; antibody Fab domains; or ligand proteins, such as cytokines, growth factors or hormones other than gonadotropins, specific examples of which include IL-6, IFN-β, TPO, or fragments thereof.
Sequence (b) is preferably selected among a hCG, FSH, LH, TSH, inhibin subunit, or fragments thereof.
Modifications to the proteins, such as chemical or protease cleavage of the protein backbone, or chemical or enzymatic modification of certain amino acid side chains, can be used to render the components of the hybrid protein of the invention inactive. This restriction of activity may also be accomplished through the use of recombinant DNA techniques to alter the coding sequence for the hybrid protein in a way that results directly in the restriction of activity to one component, or that renders the protein more amenable to subsequent chemical or enzymatic modification.
The above hybrid proteins will result in monofunctional, bifunctional or multifunctional molecules, depending on the amino acid sequences (a) that are combined with (b). In each couple, (a) can be linked to the amino termini or to the carboxy termini of (b), or to both.
A monoclonal hybrid protein of the present invention can, for instance, comprise the extracellular domain of a gonadotropin receptor linked to one of the corresponding receptor-binding gonadotropin subunits. According to such an embodiment, the hybrid protein of the invention can be a molecule in which, for example, the FSH receptor extracellular domain is linked to FSH to increase plasma half-life and improve biological activity.
This preparation can be employed to induce follicular maturation in assisted reproduction methods, such as ovulation induction or in vitro fertilisation, and to serve as a means to dramatically amplify the biological activity of the hormone essential for the success of the process, thus reducing the requirement for both the hormone itself and the number of injections to achieve ovulation.
The FSH receptor and the production of the extracellular domain of the human FSH receptor have been described respectively in WO 92/16620 and WO 96/38575.
According to a particular embodiment, the extracellular domain of the FSH receptor (ECD) can be fused in frame with a peptide linker that contains the thrombin recognition/cleavage site (29) and represents a “tethered” arm. The peptide linker links the extracellular domain of FSH with a FSH subunit. This will allow for removal of the extracellular domain of the FSH receptor by cleavage at the thrombin cleavage site as the molecule comes in contact with thrombin in the systemic circulation.
In another embodiment, instead of the thrombin cleavage site, an enzyme recognition site for an enzyme that is found in greatest abundance in the ovary is used. In this way, as the ECD-FSH molecule travels to the ovary, it will be exposed to enzymes found in the highest concentrations in that tissue and the ECD will be removed so that the FSH can interact with the membrane bound receptor.
In yet another embodiment, instead of an enzyme recognition site, a flexible hinge region is cloned between ECD and FSH so that the ECD will not be enzymatically removed from the hormone. In this way, when the ECD-FSH molecule arrives at the ovary, a competition will be established between the hinge-attached ECD and the ECD of the FSH receptor found on the ovarian cell membrane.
In a further preferred embodiment of the invention, the hybrid protein consists of the aggregation between a couple of aa sequences, one of which contains TBP1 (or the fragments from aa 20 to aa 161 or to aa 190) as (a) and the α subunit of hCG as (b), and the other contains always TBP1 (or the same fragments as above) as (a) and the β subunit of hCG, or fragments thereof, as (b). According to this embodiment, depending on the particular sequence that is chosen as (b) (the entire β subunit of hCG, or fragments or modifications thereof), the resulting hybrid protein will have one activity (only that of TBP1) or a combination of activities (that of TBP1 with that of hCG). In this latter case the hybrid protein can be used, for example, in the combined treatment of Kaposi's sarcoma and metabolic wasting in AIDS.
In a further embodiment of the invention, one or more covalent bonds between the two subunits (b) are added to enhance the stability of the resulting hybrid protein. This can be done, e.g., by adding one or more non-native interchain disulfide bonds. The sites for these cross-links can be deduced from the known structures of the heterodimeric hormones. For example, a suitable site in hCG could be to place cysteine residues at α subunit residue Lys45 and β subunit residue Glu21, replacing a salt bridge (non-covalent bond) with a disufide bond (covalent bond). Another object of the present invention are PEGylated or other chemically modified forms of the hybrid proteins.
A further object of the present invention is a DNA molecule comprising the DNA sequence coding for the above hybrid protein, as well as nucleotide sequences substantially the same. “Nucleotide sequences substantially the same” includes all other nucleic acid sequences which, by virtue of the degeneracy of the genetic code, also code for the given amino acid sequence.
For the production of the hybrid protein of the invention, the DNA sequence (a) is obtained from existing clones, as is (b). The DNA sequence coding for the desired sequence (a) is ligated with the DNA sequence coding for the desired sequence (b). Two of these fused products are inserted and ligated into a suitable plasmid or each into a different plasmid. Once formed, the expression vector, or the two expression vectors, is introduced into a suitable host cell, which then expresses the vector(s) to yield the hybrid protein of the invention as defined above.
The preferred method for preparing the hybrid of the invention is by way of PCR technology using oligonucleotides specific for the desired sequences to be copied from the clones encoding sequences (a) and (b).
Expression of any of the recombinant proteins of the invention as mentioned herein can be effected in eukaryotic cells (e.g., yeasts, insect or mammalian cells) or prokaryotic cells, using the appropriate expression vectors. Any method known in the art can be employed.
For example the DNA molecules coding for the proteins obtained by any of the above methods are inserted into appropriately constructed expression vectors by techniques well known in the art (see Sambrook et al, 1989). Double stranded cDNA is linked to plasmid vectors by homopolymeric tailing or by restriction linking involving the use of synthetic DNA linkers or blunt-ended ligation techniques: DNA ligases are used to ligate the DNA molecules and undesirable joining is avoided by treatment with alkaline phosphatase.
In order to be capable of expressing the desired protein, an expression vector should comprise also specific nucleotide sequences containing transcriptional and translational regulatory information linked to the DNA coding the desired protein in such a way as to permit gene expression and production of the protein. First in order for the gene to be transcribed, it must be preceded by a promoter recognizable by RNA polymerase, to which the polymerase binds and thus initiates the transcription process. There are a variety of such promoters in use, which work with different efficiencies (strong and weak promoters).
For eukaryotic hosts, different transcriptional and translational regulatory sequences may be employed, depending on the nature of the host. They may be derived form viral sources, such as adenovirus, bovine papilloma virus, Simian virus or the like, where the regulatory signals are associated with a particular gene which has a high level of expression. Examples are the TK promoter of the Herpes virus, the SV40 early promoter, the yeast ga14 gene promoter, etc. Transcriptional initiation regulatory signals may be selected which allow for repression and activation, so that expression of the genes can be modulated.
The DNA molecule comprising the nucleotide sequence coding for the hybrid protein of the invention is inserted into a vector(s), having the operably linked transcriptional and translational regulatory signals, which is capable of integrating the desired gene sequences into the host cell. The cells which have been stably transformed by the introduced DNA can be selected by also introducing one or more markers which allow for selection of host cells which contain the expression vector. The marker may also provide for phototrophy to a auxotropic host, biocide resistance, e.g., antibiotics, or heavy metals such as copper, or the like. The selectable marker gene can either be directly linked to the DNA gene sequences to be expressed, or introduced into the same cell by co-transfection. Additional elements may also be needed for optimal synthesis of proteins of the invention.
Factors of importance in selecting a particular plasmid or viral vector include: the ease with which recipient cells that contain the vector may be recognized and selected from those recipient cells which do not contain the vector; the number of copies of the vector which are desired in a particular host; and whether it: is desirable to be able to “shuttle” the vector between host cells of different species.
Once the vector(s) or DNA sequence containing the construct(s) has been prepared for expression, the DNA construct(s) may be introduced into an appropriate host cell by any of a variety of suitable means: transformation, transfection, conjugation, protoplast fusion, electroporation, calcium phosphate-precipitation, direct microinjection, etc.
Host cells may be either prokaryotic or eukaryotic. Preferred are eukaryotic hosts, e.g., mammalian cells, such as human, monkey, mouse, and Chinese hamster ovary (CHO) cells, because they provide post-translational modifications to protein molecules, including correct folding or glycosylation at correct sites. Also, yeast cells can carry out post-translational peptide modifications including glycosylation. A number of recombinant DNA strategies exist which utilize strong promoter sequences and high copy number of plasmids which can be utilized for production of the desired proteins in yeast. Yeast recognizes leader sequences on cloned mammalian gene products and secretes peptides bearing leader sequences (i.e., pre-peptides).
After the introduction of the vector(s), the host cells are grown in a selective medium, which selects for the growth of vector-containing cells. Expression of the cloned gene sequence(s) results in the production of the desired proteins.
Purification of the recombinant proteins is carried out by any one of the methods known for this purpose, i.e., any conventional procedure involving extraction, precipitation, chromatography, electrophoresis, or the like. A further purification procedure that may be used in preference for purifying the protein of the invention is affinity chromatography using monoclonal antibodies which bind the target protein and which are produced and immobilized on a gel matrix contained within a column. Impure preparations containing the recombinant protein are passed through the column. The protein will be bound to the column by the specific antibody while the impurities will pass through. After washing, the protein is eluted from the gel by a change in pH or ionic strength.
The term “hybrid protein”, as used herein, generically refers to a protein which contains two or more different proteins or fragments thereof.
As used herein, “fusion protein” refers to a hybrid protein, which consists of two or more proteins, or fragments thereof, linked together covalently.
The term “aggregation”, as used herein, means the formation of strong specific non-covalent interactions between two polypeptide chains forming a complex, such as those existing between the α and β subunit of a heterodimeric hormone (such as FSH, LH, hCG or TSH).
The terms “ligand” or “ligand protein”, as used herein, refer to a molecule, other than an antibody or an immunoglobulin, capable of being bound by the ligand-binding domain of a receptor; such molecule may occur in nature, or may be chemically modified or chemically synthesised.
The term “ligand-binding domain”, as used herein, refers to a portion of the receptor that is involved in binding a ligand and is generally a portion or essentially all of the extracellular domain.
The term “receptor”, as used herein, refers to a membrane protein, whose binding with the respective ligand triggers secondary cellular responses that result in the activation or inhibition of intracellular process.
In a further aspect, the present invention provides the use of the hybrid protein as a medicament. The medicament is preferably presented in the form of a pharmaceutical composition comprising the protein of the invention together with one or more pharmaceutically acceptable carriers and/or excipients. Such pharmaceutical compositions represent yet a further aspect of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood by reference to the appended drawings, in which:
FIGS. 1 ( a ) and 1 ( b ) show the TBP(20-161)-hCGα and TBP(20-161)-hCGβ constructs, respectively, and the corresponding sequences (SEQ ID NOS:1-4).
FIGS. 2 ( a ) and 2 ( b ) show the TBP(20-190)-hCGα and TBP(20-190)-hCGβ constructs, respectively, and the corresponding sequences (SEQ ID NOS:5-8).
FIG. 3 is a schematic summary of the constructs of FIGS. 1 and 2 showing p55 TNFR1, TBP1 and TBP1 fusion contructs. The linker sequences shown on the last two lines are SEQ ID NO:9 (Ala-Gly-Ala-Ala-Pro-Gly) and SEQ ID NO:10 (Ala-Gly-Ala-Gly).
FIG. 4 is a graph illustrating the dose dependent protective effect of CHO cell expressed TBP-hCG(20-190) on TNFα-induced cytotoxicity on BT-20 cells and various controls.
FIG. 5 is a graph illustrating the dose dependent protective effect of COS cell expressed TBP-hCG(20-190) on TNFα-induced cytotoxicity on BT-20 cells and various controls.
FIG. 6 is a graph illustrating the dose dependent protective effect of affinity purified CHO cell expressed TBP-hCG(20-161) on TNFα-induced cytotoxicity on BT-20 cells and various controls.
FIG. 7 is a schematic illustration of the FSHR-EC/TR/FSHβ expression vector construct.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention will now be described by means of the following Examples, which should not be construed as in any way limiting the present invention.
EXAMPLE 1
Materials and Methods
Cell lines used in this study were obtained from the American Type Culture Collection (ATCC), 10801 University Boulevard, Manassas, Va. 20110-2209unless otherwise specified. The CHO-DUKX cell line was obtained from L. Chasin at Columbia University through D. Houseman at MIT (39). The CHO-DUKX cells, which lack a functional gene for dihydrofolate reductase, were routinely maintained in complete α-plus Modified Eagles Medium (α(+)MEM) supplemented with 10% fetal bovine serum (FBS). The COS-7 cells were routinely maintained in Dulbecco's Modified Eagles Medium (DMEM) supplemented with 10° FES. Unless specified otherwise, cells were split to maintain them in log phase of growth, and culture reagents were obtained from GIBCO (Grand Island, N.Y.).
1. Assembly of the genetic constructs encoding the hybrid proteins
The numbering assignments for the p55 TNF receptor are based on the cloning paper from Wallach (40), while the numbering assignments for the hCG subunits are based on the numbering assignments from the Fiddes cloning papers (41,42). The designation TBP, or TNF binding protein, refers to the extracellular domain portions of the TNF receptors capable of binding TNF. In these Examples, the DNA constructs will be named as TBP-hybrid proteins, with the partner and region of TEP indicated in the construct nomenclature. All of the TBP-hCG constructs contain the human growth hormone (hGH) signal peptide in place of the native p55 signal sequence. In addition, the hGH signal peptide has been placed so that it immediately precedes TBP residue Asp20, which is anticipated to make this the first residue in the mature, secreted protein. These modifications are not essential to the basic concept of using hCG as a partner of the hybrid protein.
The DNAs encoding the hybrid proteins were constructed using PCR methodology (43).
a. TBP1(20-161)-hCG
The initial TBP-hCG construct was engineered to contain the ligand binding domain from the extracellular region of the p55 TNF receptor (from Asp20 inclusive of residue Cys161) fused though a short linker to the hCG α and β subunits (starting at residues αCys7 or βPro7, respectively). This construct, hereafter referred to as TBP1(20-161)-hCG, is a heterodimer of two modified hCG subunits, TBP1(20-161)-hCGα and TBP1(20-161)-hCGβ.
The oligodeoxynucleotide primers used for the TBP1(20-161)-hCGα construct were:
primer 1(αβ)
TTT TCT CGA GAT GGC
(SEQ ID NO:11)
TAC AGG TAA GCG CCC
primer 2(α)
ACC TGG GGC AGC ACC
(SEQ ID NO:12)
GGC ACA GGA GAC ACA
CTC GTT TTC
primer 3(α)
TGT GCC GGT GCT GCC
(SEQ ID NO:13)
CCA GGT TGC CCA GAA
TGC ACG CTA CAG
primer 4(α)
TTT TGG ATC CTT AAG
(SEQ ID NO:14)
ATT TGT GAT AAT AAC
AAG TAC
These and all of the other primers described in these Examples were synthesized on an Applied Biosystems Model 392 DNA synthesis machine (ABI, Foster City, Calif.), using phosphoramidite chemistry.
Since both of the TBP-hCG subunit constructs have the same 5′-end (i.e., the 5′-end of the hGH/TBP construct), primer 1(αβ) was used for both TBP-hCG subunit constructs. The other primers used for the TBP1(20-161)-hCGβ construct were:
primer 2(β)
CCG TGG ACC AGC ACC
(SEQ ID NO:15)
AGC ACA GGA GAC ACA
CTC GTT TTC
primer 3(β)
TGT GCT GGT GCT GGT CCA CGG TGC CGC
(SEQ ID NO:16)
CCC ATC AAT
primer 4(β)
TTT TGG ATC CTT ATT GTG GGA GGA TCG
(SEQ ID NO:17)
GGG TG
Primers 2(α) and 3(β) are reverse complements, and cover both the 3′-end of the coding region for the p55 extracellular domain, and the 5′-end of the hCG α subunit. Similarly, primers 2(β) and 3(β) are also reverse complements, and cover both the 3′-end of the coding region for the p55 extracellular domain, and the 5′-end of the hCG β subunit.
Two PCR reactions were run for each of the two TBP-hCG subunit constructs. The first used primers 1(αβ) and 2 (α or β), and used as the template a plasmid encoding soluble p55 residues 20-180 preceded by the hGH signal peptide (plasmid pCMVhGHspcDNA.pA4). The second used primers 3 (α or β) and 4 (α or β), and used as the template either plasmid pSVL-hCGα or pSVL-hCGβ (44). The PCR was performed using Vent (TM) polymerase from New England Bio Labs (Beverly, Mass.) in accordance with the manufacturer's recommendations, using for each reaction 25 cycles and the following conditions:
100 μg of template DNA
1 μg of each primer
2U of Vent(TM) polymerase (New England Biolabs)
denaturation at 99° C. for 30 seconds annealing at:
59° C. for 30 seconds for primers 1(αβ) and 2(α)
59° C. for 30 seconds for primers 3(α) and 4(α)
57° C. for 30 seconds for primers 1(αβ) and 2(β)
63° C. for 30 seconds for primers 3(β) and 4(β) extension at 75° C. for 75 seconds.
The PCR products were confirmed to be the expected size by electrophoresis in a 2% agarose gel and ethidium bromide staining. The fragments were then purified by passage over a Wizard column (Promega) in accordance with the column manufacturer's recommendations.
The final coding sequence for TBP1(20-161)-hCGα was assembled by fusion PCR using primer 1(αβ) and primer 4(α), and using as template the purified products from the p55 and hCG α fragments obtained from the first PCR reactions. First the two templates, which due to the overlap between primers 2(α) and 3(α) could be denatured and annealed together, were passed through 10 cycles of PCR in the absence of any added primers. The conditions for these cycles were essentially the same as those used earlier, except that the annealing was done at 67° C. and the extension was performed for 2 minutes. At the end of these 10 cycles, primers 1(αβ) and 4(α) were added, and another 10 cycles were performed. The conditions for this final set of reactions was the same as used earlier, except that an annealing temperature of 59° C. was used, and the extension was performed for 75 seconds.
Analysis of the products of this reaction by electrophoresis in a 1% agarose gel confirmed that the expected fragment of about 1100 bp was obtained. The reaction was passed over a Wizard column to purify the fragment, which was then digested with XbaI and BamHI and re-purified in a 0.7% low-melting point agarose gel. The purified fragment was subcloned into plasmid pSVL (Pharmacia), which had first been digested with XbaI and BamHI and gel purified on a 0.8% low-melting point agarose gel. Following ligation with T4 ligase, the mixture was used to transform AG1 E. coli and then plated onto LB/ampicillin plates for overnight culture at 37° C. Plasmid DNAs from ampicillin-resistant colonies were analyzed by digestion with XhoI and BamHI to confirm the presence of the insert (which is excised in this digest). Six clones were found to contain inserts, and one (clone 7) was selected for further advancement and designated pSVLTBPhCGα (containing TBP1(20-161)-hCGα). Dideoxy DNA sequencing (using Sequenase™, U.S. Biochemicals, Cleveland, Ohio) of the insert in this vector confirmed that the construct was correct, and that no undesired changes had been introduced.
The final coding sequence for TBP1(20-161)-hCGβ was assembled in a manner similar to that described for TBP1(20-161)-hCGα using fusion PCR and primers 1(αβ) and 4(β), and using as template the purified products from the p55 and hCG β fragments obtained from the first PCR reactions. The resulting pSVL plasmid containing the insert of interest was designated pSVLTBPhCGβ.
b. TBP(20-190)-hCG
A second set of TBP-hCG proteins was prepared by modification of the TBP(20-161)-hCG constructs to produce an analog containing TBP spanning from Asp20 to Thr190, in place of the 20-161 region in the initial analog. This was done by replacing the fragment between the BglII and XbaI sites in plasmid pSVLTBPhCGα with a PCR fragment containing the change. This PCR fragment was generated using fusion PCR. The primers were:
primer 1
TTT TAG ATC TCT TCT TGC
(SEQ ID NO:18)
ACA GTG GAC
primer 2
TGT GGT GCC TGA GTC CTC
(SEQ ID NO:19)
AGT
primer 3
ACT GAG GAC TCA GGC ACC
(SEQ ID NO:20)
ACA GCC GGT GCT GCC CCA
GGT TG
primer 4
TTT TTC TAG AGA AGC AGC
(SEQ ID NO:21)
AGC AGC CCA TG
Primers 1 and 2 were used to generate the sequence coding the additional p55 residues from 161-190. The PCR reaction was performed essentially as described earlier, using 1 μg of each primer and pUC-p55 as template. Similarly, primers 3 and 4 were used to generate by PCR the linker between the 3′-end of the TBP-coding region, and the 5′-end of the hCG α subunit coding region, using as a template plasmid pSVLTBPhCGα. Products from these PCR reactions were confirmed to be the correct size (about 296 bp and 121 bp respectively) by polyacrylamide gel electrophoresis (PAGE) on an 8% gel, and were then purified using a Wizard column. The design of primers 2 and 3 was such that they contained a region of overlap, so that the two PCR products (from primers 1 and 2, and from primers 3 and 4) could be annealed for fusion PCR with primers 1 and 4. Subsequent to the fusion reaction, the desired product of about 400 bp was confirmed and purified using a 1.5% agarose gel and a Wizard column. This DNA was then digested with BglII and XbaI, and ligated with BglII/XbaI-digested pSVLTBPhCGα. The presence of an insert in plasmids isolated from transformed AG1 E. coli was confirmed by digestion with BglII and XbaI. The new construct was designated pSVLTBP(20-190)-hCGα.
Similarly, plasmid pSVLTBPhCGβ was modified by substitution of the BglII-XcmI fragment. However, this was done by subcloning of a single PCR product, rather than with a fusion PCR product. Primers 1 and 2b (see below) were used with pUC-p55 as the template.
primer 2b
TTT TCC ACA GCC AGG GTG
(SEQ ID NO:22)
GCA TTG ATG GGG CGG CAC
CGT GGA CCA GCA CCA GCT
GTG GTG CCT GAG TCC TCA
GTG
The resulting PCR product (about 337 bp) was confirmed and purified as described above, digested with BglII and XcmI, and then ligated into BglII/XbaI-digested pSVLTBPhCGβ. The presence of an insert in plasmids isolated from transformed AG1 E. coli was confirmed by digestion with BglII and XcmI. The new construct was designated pSVLTBP(20-190)-hCGβ.
The new constructs were subsequently confirmed by DNA sequencing.
In addition to producing these new pSVL-based plasmids, these constructs were also subcloned into other expression vectors likely to be more suitable for stable expression in CHO, particularly vector Dα, previously described as plasmid CLH3AXSV2DHFR (45). This was accomplished by converting a BamHI site flanking the inserts in the pSVL-based vectors to an XhoI site, and then excising the insert with XhoI and cloning it into XhoI digested Dα.
2. Transient and stable expression of the hybrid proteins
Transfections of COS-7 cells (ATCC CRL 1651, ref. 46) for transient expression of the TBP-hCG hybrid proteins were performed using electroporation (47). Exponentially growing COS-7 cells were removed by trypsinization, collected by gentle centrifugation (800 rpm, 4 minutes), washed with cold phosphate buffered saline (PBS), pH 7.3-7.4, and then repelleted by centrifugation. Cells were resuspended at a concentration of 5×10 6 cells per 400 μl cold PBS and mixed with 10 μg of plasmid DNA in a prechilled 2 mm gap electroporation cuvette. For cotransfections, 5 μg of each plasmid were used. The cuvette and cells were chilled on ice for a further 10 minutes, and then subjected to electroporation using a BTX Model 600 instrument and conditions of 125 V, 950 μF and R=8. Afterward the cells were set to cool on ice for 10 minutes, transferred to a 15 ml conical tube containing 9.5 ml complete medium (Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% fetal bovine serum (FBS) and 1% L-glutamine) at room temperature, and left at room temperature for 5 minutes. After gentle mixing in the 15 ml tube, the entire contents was seeded onto two P100 plates and placed into a 37° C., 5% CO 2 incubator. After 18 hours the media was changed, and in some cases the new media contained only 1% or 0% FBS. After another 72 hours, the conditioned media was harvested, centrifuged to remove cells, and then stored frozen at −70° C.
Transfections of CHO-DUKX (CHO) cells for transient or stable expression were performed using calcium phosphate precipitation of DNA. Twenty-four hours prior to the transfection, exponentially growing CHO cells were plated onto 100 mm culture plates at a density of 7.5×10 5 cells per plate. On the day of the transfection, 10 μg of plasmid DNA was brought to 0.5 ml in transfection buffer (see below), 31 μl of 2 M CaCl 2 were added, the DNA-CaCl 2 solution was mixed by vortexing, and left to stand at room temperature for 45 minutes. After this the media was aspirated from the plates, the DNA was added to the cells using a sterile plastic pipette, and the cells were left at room temperature for 20 minutes. At the end of this period, 5 ml of complete α(+)MEM containing 10% FBS was added to the plates, which were incubated at 37° C. for 4-6 hours. The media was then aspirated off the plates, and the cells were subjected to a glycerol shock by incubating them with a solution of 15% glycerol in transfection buffer at 37° C. for 3.5 minutes. After removal of the glycerol solution, the cells were washed twice with PBS, refed with 10 ml complete α(+)MEM, 10% FBS, and returned to the 37° C. incubator. For stable transfections, after 48 hours the cells were split 1:10 and fed with selection medium (complete α-minus MEM (lacking nucleosides), 10% dialyzed FBS, and 0.02 μM methotrexate). Non-transfected (non-resistant) cells were typically eliminated in 3-4 weeks, leaving a population of transfected, methotrexate-resistant cells.
3. Quantitation of expression
Secretion of the hybrid proteins by transfected cells was assessed using a commercial assay kit for soluble p55 (R&D Systems; Minneapolis, Minn.) in accordance with the manufacturer's instructions. This assay also provides an estimate of the hybrid protein levels in conditioned and processed media, which served as the basis for selecting doses to be used in the bioassay.
4. Assessment of heterodimer formation
To assess the ability of the TBP-hCG subunit fusions to combine and form heterodimers, a sandwich immunoassay using antibodies to the hCG subunits was performed. In this assay, a monoclonal antibody to the hCG β subunit is coated onto microtiter plates and used for analyte capture. The primary detection antibody is a goat polyclonal raised against the human TSH α subunit (#082422G—Biodesign International; Kennenbunkport, Ma.), which is in turn detected using a horse radish peroxidase conjugated rabbit anti-goat polyclonal antibody (Cappel; Durham, N.C.).
Several different anti-hCG β subunit antibodies were used in this work, all of which show no detectable cross-reactivity with the free α subunit. One of these antibodies ({fraction (3/6)}) is used in the commercially available MAIAclone hCG assay kit (Biodata; Rome, Italy).
High-protein binding microtiter plates (Costar #3590) were coated with capture antibody by incubation (2 hours at 37° C.) with 100 μl/well of a 5 μg/ml solution of antibody in coating buffer (PBS, pH 7.4, 0.1 mM Ca ++ , 0.1 mM Mg ++ ). After washing once with wash solution (PBS, pH 7.4+0.1 Tween 20) the plate is blocked by completely filling the wells (≈400 μl/well) with blocking solution (3% bovine serum albumin (BSA; fraction V—A-4503 Sigma) in PBS, pH 7.4) and incubating for one hour at 37° C. or overnight at 4° C. The plate is then washed twice with wash solution, and the reference and experimental samples, diluted in diluent (5 mg/ml BSA in PBS, pH 7.4) to yield a 100 μl volume, are added. After incubating the samples and the plate for two hours at 37° C., the plate is again twice washed with wash solution. The primary detection antibody, diluted 1:5000 in diluent, is added (100 μl/well) and incubated for one hour at 37° C. The secondary detection antibody (HRP conjugated rabbit anti-goat Ig), diluted 1:5000 in diluent, is added (100 μl/well) and after incubation for one hour at 37° C., the plate is washed three times with wash solution. One hundred μl of TMB substrate solution (Kirkegaard and Perry Laboratories) is added, the plate is incubated 20 minutes in the dark at room temperature, and then the enzymatic reaction is stopped by addition of 50 μl/well 0.3M H 2 SO 4 . The plate is then analyzed using a microtiter plate reader set for a wavelength of 450 nm.
5. Partial purification
To better quantitate the activities of these hybrid proteins, TBP-hCG hybrid proteins were partially purified by immunoaffinity chromatography. The antibody used was a monoclonal commercially available from R&D Systems (MAB #225). The column was CNBr-activated sepharose, charged with the antibody by following the manufacturer's (Pharmacia) instructions.
Conditioned media was collected from confluent T-175 flasks of each line using daily harvests of 50 ml SFMII media (GIBCO), five harvests for each line. The collections were subjected to centrifugation (1000 RPM) to remove cellular debris. The material was then assayed for TBP content using the commercial immunoassay and concentrated (Centricon units by Amicon; Beverly, Mass.) so that the apparent TBP concentration was about 50 ng/ml.
Ten ml of the concentrated TBP-hCG (sample #18873) was brought to approximately 1 M NaCl by addition of NaCl and adjustment of the solution to a conductivity of approximately 85 mS/cm. This was passed through a 0.5 ml anti-TBP immunoaffinity column. The flow-through was collected and run through the column a second time. After this the column was washed with 1 M NaCl in PBS. The bound TBP(20-161)-hCG was collected after elution with 50 mM citric acid (pH 2.5). The eluate (approximately 7 ml) was concentrated by filtration using Amicon Centricon-10's in accordance with the manufacturer's (Amicon) instructions, to a volume of approximately 200 μl. Approximately 800 μl of PBS was added to bring the sample volume to 1 ml, which was stored at 4° C. until tested by bioassay.
6. Assessment of anti-TNF activity
Numerous in vitro TNF-induced cytotoxicity assays have been described for evaluating analogs of soluble TNF receptors. We utilized an assay employing a human breast carcinoma cell line, BT-20 cells (ATCC HTB 19). The use of these cells as the basis for a TNF bioassay has been described previously (48). These cells are cultured at 37° C. in RPMI 1640 media supplemented with 10% heat-inactivated FBS. The cells were grown to a maximum 80-90% confluence, which entailed splitting every 3-4 days with a seeding density of about 3×10 6 cells per T175cm 2 flask.
The BT-20 assay uses the inclusion of a cellular stain, crystal violet, as a detection method to assess survival of cells after treatment with TNF. Dead cells are unable to take up and retain the dye.
In brief, the protocol used for the assay of anti-TNF activity is the following. Recombinant human TNFα (R&D Systems) and the experimental samples are constituted in media (RPMI 1640 with 5% heat-inactivated FBS) and added to the wells of 96-well culture plates. The cells are then plated into these wells at a density of 1×10 5 cells/well. The quantity of TNFα added was determined earlier in titration studies, and represents a dose at which about 50% of the cells are killed.
After addition of the samples, the cells are cultured for 48 hours at 39° C., after which the proportion of live cells is determined using crystal violet staining and a microtiter plate reader (570 nm).
RESULTS
1. Constructs under study
The designs of the hybrid proteins studied are briefly summarized below; two control proteins, a monomeric soluble p55 (r-hTBP-1) and a dimeric TBP-immunoglobulin fusion protein (TBP-IgG3) (prepared essentially as described in (10)), were studied for comparative purposes.
Fusion
Construct
TBP N-term
TBP C-term
partner
r-hTBP-1
mix of 9 and 20
180
none
TBP-IgG3
mix of 9 and 20
190
IgG3 heavy chain
constant region
TBP(20-161)-hCG
20
161
hCGα and hCGβ
(heterodimer)
TBP(20-190)-hCG
20
190
hCGα and hCGβ
(heterodimer)
The sequences of the DNAs encoding, TBP(20-190)-hCG and TBP(20-161)-hCG are provided in FIGS. 1 and 2, respectively. A schematic summary of the constructs is provided in FIG. 3 .
2. Secretion of TBP-hCG proteins
All of the constructs tested were found to be produced and secreted into culture media by transfected mammalian cells. Data illustrating this are shown in Tables 1 and 2.
TABLE 1
COS-7 transient expression (TBP
ELISA)
Concentration
Hyprid Protein
(pg/ml)
TBP1
66
TBP-hCGα(20-161)
5.1
TBP-hCGβ(20-161)
0.5
TBP-hCG(20-161)
2.7
control
<0.25
Constructs were expressed using pSVL (Pharmacia)
TABLE 2
COS-7 transient expression (TBP
ELISA)
Hybrid
Concentration
protein
(ng/ml)
TBP1
131
TBP-hCGα(20-190)
81
TBP-hCGβ(20-190)
9
TBP-hCG(20-190)
62
control
<1
Constructs were expressed using a mouse metallothionein promoter-containing vector - pDα
3. TBP-hCG(α/β) fusion proteins assemble into heterodimers
The combination of TBP-hCGα and TBP-hCGβ was confirmed using the sandwich assay for the hCG heterodimer. Only the combined transfection of α and β subunit fusions resulted in heterodimer detection (Table 3).
TABLE 3
COS-7 transient expression
(hCG heterodimer assay)
Hybrid
Concentration
protein
(ng/ml)
TBP1
<0.2
TBP-hCGα(20-190)
<0.2
TBP-hCGβ(20-190)
<0.2
TBP-hCG(20-190)
38
control
<0.2
Constructs were expressed using a mouse metallothionein promoter-contaning vector - pDα
4. TBP-hCG hybrid proteins exhibit increased activity over TBP monomer
Hybrid proteins produced in either COS-7 or CHO cells were found to be potent inhibitors of TNFα in the BT-20 bioassay. Some of the samples tested are summarized in Table 4.
TABLE 4
Samples tested for anti-TNF activity
Cell
Nature of
Construct
source
sample
r-hTBP-1
CHO
purified
TBP-IgG3
CHO
1x conditioned media
TBP(20-161)-hCG
CHO
immunopurified (anti-TBP)
TBP(20-190)-hCG
CHO
1x conditioned media
TBP(20-190)-hCG
COS
1x conditioned media
Negative controls (conditioned media from mock transfections) were included for the 1x media samples.
As illustrated in FIGS. 4-6 (points on y-axis), addition of TNF (2.5 ng/ml) results in a clear reduction in live cell number (as assessed by OD 570). In every case, active samples have as a maximal protective effect the restoration of cell viability to the level seen in the absence of added TNF (i.e., the control labeled “cells alone”).
The positive controls, r-hTBP-1 and TBP-IgG3, are both protective, showing a clear dose-dependence and ED50s of approximately 100 ng/ml for the r-hTBP-1 (FIGS. 4-6) and about 1.5 ng/ml for TBP-IgG3 (FIG. 4) respectively.
The TBP-hCG constructs from 1x media (CHO or COS) or from the immunopurification show dose-dependent protection, with approximate ED50s ranging from 2-11 ng/ml (FIGS. 4 - 6 ).
The results from the in vitro bioassay are reported in Table 5. The data indicate that the hybrid proteins inhibit TNF cytotoxicity, and that they are substantially more potent than the TBP monomer. The negative controls were devoid of protective activity.
TABLE 5
Preliminary Assessment of the hybrid proteins in TNF
Cytotoxicity Assay
Anti-TNF
activity
(ED50) in
BT-20
Construct
Fusion partner
bioassay**
r-hTBP-1
none
100
ng/ml
TBP-IgG3
IgG3 heavy chain constant region
1.5
ng/ml
TBP(20-161)-hCG
hCGα and hCGβ (heterodimer)
2
ng/ml
TBP(20-190)-hCG
hCGα and hCGβ (heterodimer)
8-11
ng/ml
**The quantitation of material for dosing and estimation of ED50 was made using the TBP ELISA.
In addition to the possibility that dimerization of TBP may increase potency, it is also possible that the activity of the hybrid proteins are not related to dimeric interaction with TBP, but rather to steric inhibition due to the partner of the hybrid interfering with soluble TBP/TNF binding to cell-surface TNF receptors.
EXAMPLE 2
Construction of a plasmid for mammalian cell expression of the FSHβ subunit tethered to the extracellular domain of the FSH receptor
The FSHβ subunit was fused to the extracellular domain of the FSH receptor (FSHR-EC) with a portion of the extracellular domain of the thrombin receptor (TR) as a tether. A thrombin cleavage site was also included. In other embodiments of the present invention, the alpha subunit could be fused to the FSHR--EC, and a tether other than the TR and a proteolytic cleavage site other than the thrombin cleavage site could be used.
The FSHR-EC/TR/FSHS fusion was constructed using a combination of standard engineering techniques including the polymerase chain reaction (PCR), synthetic DNA, restriction endonuclease digestion, gel purification of fragments, and subcloning. The FSH receptor extracellular domain was obtained from the 2.1 kb XhoI expression construct described by Kelton et al. (49). The human FSHS coding region was derived from the DdeI-Sau3AI subfragment of the 15B genomic clone described by Watkins, P. C., et al. (50). For the construct described in this example, the intron was removed to simplify the complexity of the final construct. However, removal of the intron is not essential for the practice of this invention. The thrombin receptor tether and cleavage site were assembled by PCR technology. The final construct contained in the following order: the signal peptide from the human FSH receptor (Met -17 to Gly -1 ), amino acids 1-349 of the mature human FSH receptor protein (Cys 1 to Arg 140 ), amino acids 48-99 of the human thrombin receptor (Pro 48 -Ser 99 ), the thrombin cleavage site (such as that described by Hakes, D. J. and Dixon, J. E., (51) and amino acids 1-111 of the human FSHS subunit (excluding the signal peptide of 18 amino acids). The TR tethered FSHR-EC/FSHβ fusion construct was inserted into the eukaryotic expression vector pCMVpA.4 for expression in CHO cells. A diagram of the plasmid is shown in FIG. 7 .
Preparation of cell lines which stably produce the FSH receptor extracellular domain tethered to FSH
Suitable mammalian cell lines for expression of recombinant human FSH and its derivatives include, but are not limited to, Chinese hamster ovary (CHO), mouse mammary carcinoma C127, and human embryonic kidney 293. In this example, the use of CHO cells is described.
CHO-DUKX cells are a clonal mutant of Chinese hamster ovary cells lacking dihydrofolate reductase activity (39). The cells were maintained in Minimum Essential Alpha Medium (MEM-α) supplemented with 10% fetal bovine serum (FBS) and 1% L-glutamine (CHO growth medium).
For calcium phosphate precipitation, a modification of the method of Graham (52) was used. CHO-DUKX cells were plated in 100-mm dishes at a density of 7.5×10 5 cells/dish and then cultured for 24 hrs prior to transfection with plasmid DNA. For the transfection, the a subunit expression plasmid DNA and the FSHR-EC/TR/FSHb expression plasmid DNA (approximately a 1:5 molar ratio, respectively) were added to 0.5 ml of transfection buffer. The transfection buffer was prepared by adding 4 g NaCl, 0.185 g KCl, 0.05 g Na 2 HPO 4 , 0.5 g dextrose, and 2.5 g HEPES to sterile distilled H 2 O then adjusting the volume to 500 ml and the pH to 7.5. To the DNA-transfection buffer solution, 31 μl of 2 M CaCl 2 was added. A 1 min incubation at room temperature was sufficient for the formation of a DNA precipitate. The culture medium was removed from the 100 mm dishes and the DNA precipitate was layered over the cells. The cells were allowed to stand at room temperature for 20 min, then 5 ml of growth medium was added and the plates were incubated for approximately 6 hrs at 37° C. The culture medium was removed and the cells were shocked by adding 5 ml of transfection buffer containing 15% glycerol, prewarmed to 37° C. After 3.5 min, the cells were rinsed twice with PBS and 10 ml growth medium was added. At 48 hrs post transfection the CHO-DUKX cells were subcultured at a 1:10 split ratio and selection medium was added. Selection medium for DHFR in CHO-DUKX cells was MEM-α without ribonucleosides and deoxyribonucleosides supplemented with 10% dialyzed FBS and 1% L-glutamine and 0.02 μM methotrexate (MTX). Increased expression levels were obtained by exposing the cells to the following stepwise increases in MTX concentrations: 0.1 μM, 0.5 μM, 1 μM, 5 μM Construction of the tethered ECD of the FSH receptor using the hinge region of the IGG gene.
In a variation of CMV/FSHR-EC/TR/FSHS, the thrombin receptor tether and cleavage site are removed and replaced with, for example, the hinge region of human IgGl, such that the ECD will not be proteolytically removed from the hormone. This construct, CMV/FSHR-EC/Hinge/FSHβ, is assembled by PCR technology. The final construct contained in the following order: the signal peptide from the human FSH receptor (Met-17 to Gly-1), amino acids 1-349 of the mature human FSH receptor protein (Cysl to Arg349), amino acids EPKSCDKTHTCPPCP of the human IgGi hinge (Nabil Reference), amino acids 1-111 of the human FSH subunit (excluding the signal peptide of 18 amino acids). Instead of using the IgGi hinge region as a flexible hinge region, a flexible spacer such as polyglycine could also be used. A cleavage site for a protease other than thrombin, and found in the ovary (plasminogen) could also be included in or near the spacer or hinge.
All references cited herein, including journal articles or abstracts, published or corresponding U.S. or foreign patent applications, issued U.S. or foreign patents, or any other references, are entirely incorporated by reference herein, including all data, tables, figures, and text presented in the cited references. Additionally, the entire contents of the references cited within the references cited herein are also entirely incorporated by reference.
Reference to known method steps, conventional method steps, known methods or conventional methods is not in any way an admission that any aspect, description or embodiment of the present invention is disclosed, taught or suggested in the relevant art.
The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying knowledge within the skill of the art (including the contents of the references cited herein), readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present invention. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance presented herein, in combination with the knowledge of one of ordinary skill in the art.
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52. Graham, Virology 52:456, 1973.
22
1049 base pairs
nucleic acid
single
linear
cDNA
unknown
CDS
278..1047
1
TCCACATGGC TACAGGTAAG CGCCCCTAAA ATCCCTTTGG GCACAATGTG TCCTGAGGGG 60
AGAGGCAGCG ACCTGTAGAT GGGACGGGGG CACTAACCCT CAGGTTTGGG GCTTCTCAAT 120
CTCACTATCG CCATGTAAGC CCAGTATTTG GCCAATCTCA GAAAGCTCCT CCTCCCTGGA 180
GGGATGGAGA GAGAAAAACA AACAGCTCCT GGAGCAGGGA GAGTGCTGGC CTCTTGCTCT 240
CCGGCTCCCT CTGTTGCCCT CTGGTTTCTC CCCAGGC TCC CGG ACG TCC CTG CTC 295
Ser Arg Thr Ser Leu Leu
1 5
CTG GCT TTT GGC CTG CTC TGC CTG CCC TGG CTT CAA GAG GGC AGT GCC 343
Leu Ala Phe Gly Leu Leu Cys Leu Pro Trp Leu Gln Glu Gly Ser Ala
10 15 20
GAT AGT GTG TGT CCC CAA GGA AAA TAT ATC CAC CCT CAA AAT AAT TCC 391
Asp Ser Val Cys Pro Gln Gly Lys Tyr Ile His Pro Gln Asn Asn Ser
25 30 35
ATT TGC TGT ACC AAG TGC CAC AAA GGA ACC TAC TTG TAC AAT GAC TGT 439
Ile Cys Cys Thr Lys Cys His Lys Gly Thr Tyr Leu Tyr Asn Asp Cys
40 45 50
CCA GGC CCG GGG CAG GAT ACG GAC TGC AGG GAG TGT GAG AGC GGC TCC 487
Pro Gly Pro Gly Gln Asp Thr Asp Cys Arg Glu Cys Glu Ser Gly Ser
55 60 65 70
TTC ACC GCT TCA GAA AAC CAC CTC AGA CAC TGC CTC AGC TGC TCC AAA 535
Phe Thr Ala Ser Glu Asn His Leu Arg His Cys Leu Ser Cys Ser Lys
75 80 85
TGC CGA AAG GAA ATG GGT CAG GTG GAG ATC TCT TCT TGC ACA GTG GAC 583
Cys Arg Lys Glu Met Gly Gln Val Glu Ile Ser Ser Cys Thr Val Asp
90 95 100
CGG GAC ACC GTG TGT GGC TGC AGG AAG AAC CAG TAC CGG CAT TAT TGG 631
Arg Asp Thr Val Cys Gly Cys Arg Lys Asn Gln Tyr Arg His Tyr Trp
105 110 115
AGT GAA AAC CTT TTC CAG TGC TTC AAT TGC AGC CTC TGC CTC AAT GGG 679
Ser Glu Asn Leu Phe Gln Cys Phe Asn Cys Ser Leu Cys Leu Asn Gly
120 125 130
ACC GTG CAC CTC TCC TGC CAG GAG AAA CAG AAC ACC GTG TGC ACC TGC 727
Thr Val His Leu Ser Cys Gln Glu Lys Gln Asn Thr Val Cys Thr Cys
135 140 145 150
CAT GCA GGT TTC TTT CTA AGA GAA AAC GAG TGT GTC TCC TGT GCC GGT 775
His Ala Gly Phe Phe Leu Arg Glu Asn Glu Cys Val Ser Cys Ala Gly
155 160 165
GCT GCC CCA GGT TGC CCA GAA TGC ACG CTA CAG GAA AAC CCA TTC TTC 823
Ala Ala Pro Gly Cys Pro Glu Cys Thr Leu Gln Glu Asn Pro Phe Phe
170 175 180
TCC CAG CCG GGT GCC CCA ATA CTT CAG TGC ATG GGC TGC TGC TTC TCT 871
Ser Gln Pro Gly Ala Pro Ile Leu Gln Cys Met Gly Cys Cys Phe Ser
185 190 195
AGA GCA TAT CCC ACT CCA CTA AGG TCC AAG AAG ACG ATG TTG GTC CAA 919
Arg Ala Tyr Pro Thr Pro Leu Arg Ser Lys Lys Thr Met Leu Val Gln
200 205 210
AAG AAC GTC ACC TCA GAG TCC ACT TGC TGT GTA GCT AAA TCA TAT AAC 967
Lys Asn Val Thr Ser Glu Ser Thr Cys Cys Val Ala Lys Ser Tyr Asn
215 220 225 230
AGG GTC ACA GTC ATG GGG GGT TTC AAA GTG GAG AAC CAC ACG GGG TGC 1015
Arg Val Thr Val Met Gly Gly Phe Lys Val Glu Asn His Thr Gly Cys
235 240 245
CAC TGC AGT ACT TGT TAT TAT CAC AAA TCT TA AG 1049
His Cys Ser Thr Cys Tyr Tyr His Lys Ser
250 255
256 amino acids
amino acid
linear
protein
unknown
2
Ser Arg Thr Ser Leu Leu Leu Ala Phe Gly Leu Leu Cys Leu Pro Trp
1 5 10 15
Leu Gln Glu Gly Ser Ala Asp Ser Val Cys Pro Gln Gly Lys Tyr Ile
20 25 30
His Pro Gln Asn Asn Ser Ile Cys Cys Thr Lys Cys His Lys Gly Thr
35 40 45
Tyr Leu Tyr Asn Asp Cys Pro Gly Pro Gly Gln Asp Thr Asp Cys Arg
50 55 60
Glu Cys Glu Ser Gly Ser Phe Thr Ala Ser Glu Asn His Leu Arg His
65 70 75 80
Cys Leu Ser Cys Ser Lys Cys Arg Lys Glu Met Gly Gln Val Glu Ile
85 90 95
Ser Ser Cys Thr Val Asp Arg Asp Thr Val Cys Gly Cys Arg Lys Asn
100 105 110
Gln Tyr Arg His Tyr Trp Ser Glu Asn Leu Phe Gln Cys Phe Asn Cys
115 120 125
Ser Leu Cys Leu Asn Gly Thr Val His Leu Ser Cys Gln Glu Lys Gln
130 135 140
Asn Thr Val Cys Thr Cys His Ala Gly Phe Phe Leu Arg Glu Asn Glu
145 150 155 160
Cys Val Ser Cys Ala Gly Ala Ala Pro Gly Cys Pro Glu Cys Thr Leu
165 170 175
Gln Glu Asn Pro Phe Phe Ser Gln Pro Gly Ala Pro Ile Leu Gln Cys
180 185 190
Met Gly Cys Cys Phe Ser Arg Ala Tyr Pro Thr Pro Leu Arg Ser Lys
195 200 205
Lys Thr Met Leu Val Gln Lys Asn Val Thr Ser Glu Ser Thr Cys Cys
210 215 220
Val Ala Lys Ser Tyr Asn Arg Val Thr Val Met Gly Gly Phe Lys Val
225 230 235 240
Glu Asn His Thr Gly Cys His Cys Ser Thr Cys Tyr Tyr His Lys Ser
245 250 255
1202 base pairs
nucleic acid
single
linear
cDNA
unknown
CDS
279..1199
3
CTCGAGATGG CTACAGGTAA GCGCCCCTAA AATCCCTTTG GGCACAATGT GTCCTGAGGG 60
GAGAGGTAGC GACCTGTAGA TGGGACGGGG GCACTAACCC TGAGGTTTGG GGCTTCTGAA 120
TGTGAGTATC GCCATGTAAG CCCAGTATTT GGCCAATGTC AGAAAGCTCC TGGTCCCTGG 180
AGGGATGGAG AGAGAAAAAC AAACAGCTCC TGGAGCAGGG AGAGTGCTGG CCTCTTGCTC 240
TCCGGCTCCC TCTGTTGCCC TGTGGTTTCT CCCCAGGC TCC CGG ACG TCC CTG 293
Ser Arg Thr Ser Leu
260
CTC CTG GCT TTT GGC CTG CTC TGC CTG CCC TGG CTT CAA GAG GGC AGT 341
Leu Leu Ala Phe Gly Leu Leu Cys Leu Pro Trp Leu Gln Glu Gly Ser
265 270 275
GCC GAT AGT GTG TGT CCC CAA GGA AAA TAT ATC CAC CCT CAA AAT AAT 389
Ala Asp Ser Val Cys Pro Gln Gly Lys Tyr Ile His Pro Gln Asn Asn
280 285 290
TCG ATT TGC TGT ACC AAG TGC CAC AAA GGA ACC TAC TTG TAC AAT GAC 437
Ser Ile Cys Cys Thr Lys Cys His Lys Gly Thr Tyr Leu Tyr Asn Asp
295 300 305
TGT CCA GGC CCG GGG CAG GAT ACG GAC TGC AGG GAG TGT GAG AGC GGC 485
Cys Pro Gly Pro Gly Gln Asp Thr Asp Cys Arg Glu Cys Glu Ser Gly
310 315 320 325
TCT TTC ACC GCT TCA GAA AAC CAC CTC AGA CAC TGC CTC AGC TGC TCC 533
Ser Phe Thr Ala Ser Glu Asn His Leu Arg His Cys Leu Ser Cys Ser
330 335 340
AAA TGC CGA AAG GAA ATG GGT CAG GTG GAG ATC TCT TCT TGC ACA GTG 581
Lys Cys Arg Lys Glu Met Gly Gln Val Glu Ile Ser Ser Cys Thr Val
345 350 355
GAC CGG GAC ACC GTG TGT GGC TGC AGG AAG AAC CAG TAC CGG CAT TAT 629
Asp Arg Asp Thr Val Cys Gly Cys Arg Lys Asn Gln Tyr Arg His Tyr
360 365 370
TGG AGT GAA AAC CTT TTC CAG TGC TTC AAT TGC AGC CTC TGC CTC AAT 677
Trp Ser Glu Asn Leu Phe Gln Cys Phe Asn Cys Ser Leu Cys Leu Asn
375 380 385
GGG ACC GTG CAC CTC TCC TGC CAG GAG AAA CAG AAC ACC GTG TGC ACC 725
Gly Thr Val His Leu Ser Cys Gln Glu Lys Gln Asn Thr Val Cys Thr
390 395 400 405
TGC CAT GCA GGT TTC TTT CTA AGA GAA AAC GAG TGT GTC TCC TGT GCT 773
Cys His Ala Gly Phe Phe Leu Arg Glu Asn Glu Cys Val Ser Cys Ala
410 415 420
GGT GCT GGT CCA CGG TGC CGC CCC ATC AAT GCC ACC CTG GCT GTG GAG 821
Gly Ala Gly Pro Arg Cys Arg Pro Ile Asn Ala Thr Leu Ala Val Glu
425 430 435
AAG GAG GGC TGC CCC GTG TGC ATC ACC GTC AAC ACC ACC ATC TGT GCC 869
Lys Glu Gly Cys Pro Val Cys Ile Thr Val Asn Thr Thr Ile Cys Ala
440 445 450
GGC TAC TGC CCC ACC ATG ACC CGC GTG CTG CAG GGG GTC CTC CCC GCC 917
Gly Tyr Cys Pro Thr Met Thr Arg Val Leu Gln Gly Val Leu Pro Ala
455 460 465
CTG CCT CAG GTG GTG TGC AAC TAC CGC GAT GTG CGC TTC GAG TCC ATC 965
Leu Pro Gln Val Val Cys Asn Tyr Arg Asp Val Arg Phe Glu Ser Ile
470 475 480 485
CGG CTC CCT GGC TGC CCG CGC GGC GTG AAC CCC GTG GTC TCC TAC GCT 1013
Arg Leu Pro Gly Cys Pro Arg Gly Val Asn Pro Val Val Ser Tyr Ala
490 495 500
GTG GCT CTC AGC TGT CAA TGT GCA CTC TGC CGC CGC AGC ACC ACT GAC 1061
Val Ala Leu Ser Cys Gln Cys Ala Leu Cys Arg Arg Ser Thr Thr Asp
505 510 515
TGC GGG GGT CCC AAG GAC CAC CCC TTG ACC TGT GAT GAC CCC CGC TTC 1109
Cys Gly Gly Pro Lys Asp His Pro Leu Thr Cys Asp Asp Pro Arg Phe
520 525 530
CAG GAC TCC TCT TCC TCA AAG GCC CCT CCC CCC AGC CTT CCA AGC CCA 1157
Gln Asp Ser Ser Ser Ser Lys Ala Pro Pro Pro Ser Leu Pro Ser Pro
535 540 545
TCC CGA CTC CCG GGG CCC TCG GAC ACC CCG ATC CTC CCA CAA TAA 1202
Ser Arg Leu Pro Gly Pro Ser Asp Thr Pro Ile Leu Pro Gln
550 555 560
307 amino acids
amino acid
linear
protein
unknown
4
Ser Arg Thr Ser Leu Leu Leu Ala Phe Gly Leu Leu Cys Leu Pro Trp
1 5 10 15
Leu Gln Glu Gly Ser Ala Asp Ser Val Cys Pro Gln Gly Lys Tyr Ile
20 25 30
His Pro Gln Asn Asn Ser Ile Cys Cys Thr Lys Cys His Lys Gly Thr
35 40 45
Tyr Leu Tyr Asn Asp Cys Pro Gly Pro Gly Gln Asp Thr Asp Cys Arg
50 55 60
Glu Cys Glu Ser Gly Ser Phe Thr Ala Ser Glu Asn His Leu Arg His
65 70 75 80
Cys Leu Ser Cys Ser Lys Cys Arg Lys Glu Met Gly Gln Val Glu Ile
85 90 95
Ser Ser Cys Thr Val Asp Arg Asp Thr Val Cys Gly Cys Arg Lys Asn
100 105 110
Gln Tyr Arg His Tyr Trp Ser Glu Asn Leu Phe Gln Cys Phe Asn Cys
115 120 125
Ser Leu Cys Leu Asn Gly Thr Val His Leu Ser Cys Gln Glu Lys Gln
130 135 140
Asn Thr Val Cys Thr Cys His Ala Gly Phe Phe Leu Arg Glu Asn Glu
145 150 155 160
Cys Val Ser Cys Ala Gly Ala Gly Pro Arg Cys Arg Pro Ile Asn Ala
165 170 175
Thr Leu Ala Val Glu Lys Glu Gly Cys Pro Val Cys Ile Thr Val Asn
180 185 190
Thr Thr Ile Cys Ala Gly Tyr Cys Pro Thr Met Thr Arg Val Leu Gln
195 200 205
Gly Val Leu Pro Ala Leu Pro Gln Val Val Cys Asn Tyr Arg Asp Val
210 215 220
Arg Phe Glu Ser Ile Arg Leu Pro Gly Cys Pro Arg Gly Val Asn Pro
225 230 235 240
Val Val Ser Tyr Ala Val Ala Leu Ser Cys Gln Cys Ala Leu Cys Arg
245 250 255
Arg Ser Thr Thr Asp Cys Gly Gly Pro Lys Asp His Pro Leu Thr Cys
260 265 270
Asp Asp Pro Arg Phe Gln Asp Ser Ser Ser Ser Lys Ala Pro Pro Pro
275 280 285
Ser Leu Pro Ser Pro Ser Arg Leu Pro Gly Pro Ser Asp Thr Pro Ile
290 295 300
Leu Pro Gln
305
1147 base pairs
nucleic acid
single
linear
cDNA
unknown
CDS
278..1132
5
TCGAGATGGC TACAGGTAAG CGCCCCTAAA ATCCCTTTGG GCACAATGTG TCCTGAGGGG 60
AGAGGCAGCG ACCTGTAGAT GGGACGGGGG CACTAACCCT CAGGTTTGGG GCTTTTGAAT 120
GTGAGTATGG CCATGTAAGC CCAGTATTTG CCCAATCTCA GAAAGCTCCT GGTCCCTGGA 180
GGGATGGAGA GAGAAAAACA AACAGCTCCT GGAGCAGGGA CACTCCTGGC CTCTTGCTCT 240
GCGGCTCCGT GTGTTGCCCT GTGGTTTCTC CCCACGC TCC CGG ACG TCC CTG CTC 295
Ser Arg Thr Ser Leu Leu
310
CTG GCT TTT GGC CTG CTC TGC CTG CCC TGG CTT CAA GAG GGC AGT GCC 343
Leu Ala Phe Gly Leu Leu Cys Leu Pro Trp Leu Gln Glu Gly Ser Ala
315 320 325
GAT AGT GTG TGT CCC CAA GGA AAA TAT ATC CAC CCT CAA AAT AAT TCG 391
Asp Ser Val Cys Pro Gln Gly Lys Tyr Ile His Pro Gln Asn Asn Ser
330 335 340 345
ATT TGC TGT ACC AAG TGC CAC AAA GGA ACC TAC TTG TAC AAT GAC TGT 439
Ile Cys Cys Thr Lys Cys His Lys Gly Thr Tyr Leu Tyr Asn Asp Cys
350 355 360
CCA GGC CCG GGG CAG GAT ACC GAC TGC AGG GAG TGT GAG AGC GGC TCC 487
Pro Gly Pro Gly Gln Asp Thr Asp Cys Arg Glu Cys Glu Ser Gly Ser
365 370 375
TTC ACC GCT TCA GAA AAC CAC CTC AGA CAC TGC CTC AGC TGC TCC AAA 535
Phe Thr Ala Ser Glu Asn His Leu Arg His Cys Leu Ser Cys Ser Lys
380 385 390
TGC CGA AAG GAA ATG GGT CAG GTG GAG ATC TCT TCT TGC ACA GTG GAC 583
Cys Arg Lys Glu Met Gly Gln Val Glu Ile Ser Ser Cys Thr Val Asp
395 400 405
CGG GAC ACC GTG TGT GGC TGC AGG AAG AAC CAG TAC CGG CAT TAT TGG 631
Arg Asp Thr Val Cys Gly Cys Arg Lys Asn Gln Tyr Arg His Tyr Trp
410 415 420 425
AGT GAA AAC CTT TTC CAG TGC TTC AAT TGC ACC CTC TGC CTC AAT GGG 679
Ser Glu Asn Leu Phe Gln Cys Phe Asn Cys Thr Leu Cys Leu Asn Gly
430 435 440
ACC GTG CAC CTC TCC TGT CAG GAG AAA CAG AAC ACC GTC TGC ACC TGC 727
Thr Val His Leu Ser Cys Gln Glu Lys Gln Asn Thr Val Cys Thr Cys
445 450 455
CAT GCA GGT TTC TTT CTA AGA GAA AAC GAG TGT GTC TCC TGT AGT AAC 775
His Ala Gly Phe Phe Leu Arg Glu Asn Glu Cys Val Ser Cys Ser Asn
460 465 470
TGT AAG AAA AGC CTG GAG TGC ACG AAG TTG TCC CTA CCC CAG ATT GAG 823
Cys Lys Lys Ser Leu Glu Cys Thr Lys Leu Ser Leu Pro Gln Ile Glu
475 480 485
AAT GTT AAG GGC ACT GAG GAC TCA GGC ACC ACA GCC GGT GCT GCC CCA 871
Asn Val Lys Gly Thr Glu Asp Ser Gly Thr Thr Ala Gly Ala Ala Pro
490 495 500 505
GGT TGC CCA GAA TGC ACG CTA CAG GAA AAC CCA TTC TTC TCC CAG CCG 919
Gly Cys Pro Glu Cys Thr Leu Gln Glu Asn Pro Phe Phe Ser Gln Pro
510 515 520
GGT GCC CCA ATA CTT CAG TGC ATG GGC TGC TGC TTC TCT AGA GCA TAT 967
Gly Ala Pro Ile Leu Gln Cys Met Gly Cys Cys Phe Ser Arg Ala Tyr
525 530 535
CCC ACT CCA CTA AGG TCC AAG AAG ACG ATG TTG GTC CAA AAG AAC GTC 1015
Pro Thr Pro Leu Arg Ser Lys Lys Thr Met Leu Val Gln Lys Asn Val
540 545 550
ACC TCA GAG TCC ACT TGC TGT GTA GCT AAA TCA TAT AAC AGG GTC ACA 1063
Thr Ser Glu Ser Thr Cys Cys Val Ala Lys Ser Tyr Asn Arg Val Thr
555 560 565
GTA ATG GGG GGT TTC AAA GTG GAG AAC CAC ACG GCG TGC CAC TGC AGT 1111
Val Met Gly Gly Phe Lys Val Glu Asn His Thr Ala Cys His Cys Ser
570 575 580 585
ACT TGT TAT TAT CAC AAA TCT TAAGGATCCC TCGAG 1147
Thr Cys Tyr Tyr His Lys Ser
590
285 amino acids
amino acid
linear
protein
unknown
6
Ser Arg Thr Ser Leu Leu Leu Ala Phe Gly Leu Leu Cys Leu Pro Trp
1 5 10 15
Leu Gln Glu Gly Ser Ala Asp Ser Val Cys Pro Gln Gly Lys Tyr Ile
20 25 30
His Pro Gln Asn Asn Ser Ile Cys Cys Thr Lys Cys His Lys Gly Thr
35 40 45
Tyr Leu Tyr Asn Asp Cys Pro Gly Pro Gly Gln Asp Thr Asp Cys Arg
50 55 60
Glu Cys Glu Ser Gly Ser Phe Thr Ala Ser Glu Asn His Leu Arg His
65 70 75 80
Cys Leu Ser Cys Ser Lys Cys Arg Lys Glu Met Gly Gln Val Glu Ile
85 90 95
Ser Ser Cys Thr Val Asp Arg Asp Thr Val Cys Gly Cys Arg Lys Asn
100 105 110
Gln Tyr Arg His Tyr Trp Ser Glu Asn Leu Phe Gln Cys Phe Asn Cys
115 120 125
Thr Leu Cys Leu Asn Gly Thr Val His Leu Ser Cys Gln Glu Lys Gln
130 135 140
Asn Thr Val Cys Thr Cys His Ala Gly Phe Phe Leu Arg Glu Asn Glu
145 150 155 160
Cys Val Ser Cys Ser Asn Cys Lys Lys Ser Leu Glu Cys Thr Lys Leu
165 170 175
Ser Leu Pro Gln Ile Glu Asn Val Lys Gly Thr Glu Asp Ser Gly Thr
180 185 190
Thr Ala Gly Ala Ala Pro Gly Cys Pro Glu Cys Thr Leu Gln Glu Asn
195 200 205
Pro Phe Phe Ser Gln Pro Gly Ala Pro Ile Leu Gln Cys Met Gly Cys
210 215 220
Cys Phe Ser Arg Ala Tyr Pro Thr Pro Leu Arg Ser Lys Lys Thr Met
225 230 235 240
Leu Val Gln Lys Asn Val Thr Ser Glu Ser Thr Cys Cys Val Ala Lys
245 250 255
Ser Tyr Asn Arg Val Thr Val Met Gly Gly Phe Lys Val Glu Asn His
260 265 270
Thr Ala Cys His Cys Ser Thr Cys Tyr Tyr His Lys Ser
275 280 285
1301 base pairs
nucleic acid
single
linear
cDNA
unknown
CDS
279..1287
7
CTCGAGATGG CTACAGGTAA GCGCCCCTAA AATCCCTTTG GGCACAATGT GTCCTGAGGG 60
GAGAGGCAGC GACCTGTAGA TGGGACGGGG GCACTAACCC TCAGGTTTGG GGCTTCTGAA 120
TGTGAGTATC GCCATGTAAG CCCAGTATTT GGCCAATGTC AGAAAGCTCC TGGTCCCTGG 180
AGGGATGGAG AGAGAAAAAC AAACACCTCC TGGAGCAGGG AGAGTGCTGC CCTCTTGCTC 240
TCCGGCTCCC TCTGTTGCCC TCTGGTTTCT CCCCAGGC TCC CGG ACG TCC CTG 293
Ser Arg Thr Ser Leu
290
CTC CTG GCT TTT GGC CTG CTC TGC CTG CCC TGG CTT CAA GAG GGC AGT 341
Leu Leu Ala Phe Gly Leu Leu Cys Leu Pro Trp Leu Gln Glu Gly Ser
295 300 305
GCC GAT AGT GTG TGT CCC CAA GGA AAA TAT ATC CAC CCT CAA AAT AAT 389
Ala Asp Ser Val Cys Pro Gln Gly Lys Tyr Ile His Pro Gln Asn Asn
310 315 320
TCG ATT TGC TGT ACC AAG TGC CAC AAA GGA ACC TAC TTG TAC AAT GAC 437
Ser Ile Cys Cys Thr Lys Cys His Lys Gly Thr Tyr Leu Tyr Asn Asp
325 330 335
TGT CCA GGC CCG GGG CAG GAT ACG GAC TGC AGG GAG TGT GAG AGC GGC 485
Cys Pro Gly Pro Gly Gln Asp Thr Asp Cys Arg Glu Cys Glu Ser Gly
340 345 350
TCC TTC ACC GCT TCA GAA AAC CAC CTC AGA CAC TGC CTC AGC TGC TCC 533
Ser Phe Thr Ala Ser Glu Asn His Leu Arg His Cys Leu Ser Cys Ser
355 360 365 370
AAA TGC CGA AAG GAA ATG GGT CAG GTG GAG ATC TCT TCT TGC ACA GTG 581
Lys Cys Arg Lys Glu Met Gly Gln Val Glu Ile Ser Ser Cys Thr Val
375 380 385
GAC CGG GAC ACC GTG TGT GGC TGC AGG AAG AAC CAG TAC CGG CAT TAT 629
Asp Arg Asp Thr Val Cys Gly Cys Arg Lys Asn Gln Tyr Arg His Tyr
390 395 400
TGG AGT GAA AAC CTT TTC CAG TGC TTC AAT TGC AGC CTC TGC CTC AAT 677
Trp Ser Glu Asn Leu Phe Gln Cys Phe Asn Cys Ser Leu Cys Leu Asn
405 410 415
GGG ACC GTG CAC CTC TCC TGC CAG GAG AAA CAG AAC ACC GTG TGC ACC 725
Gly Thr Val His Leu Ser Cys Gln Glu Lys Gln Asn Thr Val Cys Thr
420 425 430
TGC CAT GCA GGT TTC TTT CTA AGA GAA AAC GAG TGT GTC TCC TGT AGT 773
Cys His Ala Gly Phe Phe Leu Arg Glu Asn Glu Cys Val Ser Cys Ser
435 440 445 450
AAC TGT AAG AAA AGC CTG GAG TGC ACG AAG TTG TGC CTA CCC CAG ATT 821
Asn Cys Lys Lys Ser Leu Glu Cys Thr Lys Leu Cys Leu Pro Gln Ile
455 460 465
GAG AAT GTT AAG GGC ACT GAG GAC TCA GGC ACC ACA GCT GGT GCT GGT 869
Glu Asn Val Lys Gly Thr Glu Asp Ser Gly Thr Thr Ala Gly Ala Gly
470 475 480
CCA CGG TGC CGC CCC ATC AAT GCC ACC CTG GCT GTG GAG AAG GAG GGC 917
Pro Arg Cys Arg Pro Ile Asn Ala Thr Leu Ala Val Glu Lys Glu Gly
485 490 495
TGC CCC GTG TGC ATC ACC GTC AAC ACC ACC ATC TGT GCC GGC TAC TGC 965
Cys Pro Val Cys Ile Thr Val Asn Thr Thr Ile Cys Ala Gly Tyr Cys
500 505 510
CCC ACC ATG ACC CGC GTG CTG CAG GGG GTC CTG CCG GCC CTG CCT CAG 1013
Pro Thr Met Thr Arg Val Leu Gln Gly Val Leu Pro Ala Leu Pro Gln
515 520 525 530
GTG GTG TGC AAC TAC CGC GAT GTG CGC TTC GAG TCC ATC CGG CTC CCT 1061
Val Val Cys Asn Tyr Arg Asp Val Arg Phe Glu Ser Ile Arg Leu Pro
535 540 545
GGC TGC CCG CGC GGC GTG AAC CCC GTG GTC TCC TAC GCC GTG GCT CTC 1109
Gly Cys Pro Arg Gly Val Asn Pro Val Val Ser Tyr Ala Val Ala Leu
550 555 560
AGC TGT CAA TGT GCA CTC TGC CGC CGC AGC ACC ACT GAC TGC GGG GGT 1157
Ser Cys Gln Cys Ala Leu Cys Arg Arg Ser Thr Thr Asp Cys Gly Gly
565 570 575
CCC AAG GAC CAC CCC TTG ACC TGT GAT GAC CCC CGC TTC CAG GAC TCC 1205
Pro Lys Asp His Pro Leu Thr Cys Asp Asp Pro Arg Phe Gln Asp Ser
580 585 590
TCT TCC TCA AAG GCC CCT CCC CCC AGC CTT CCA AGC CCA TCC CGA CTC 1253
Ser Ser Ser Lys Ala Pro Pro Pro Ser Leu Pro Ser Pro Ser Arg Leu
595 600 605 610
CCG GGG CCC TCG GAC ACC CCG ATC CTC CCA CAA T AAGGATCCCT CGAG 1301
Pro Gly Pro Ser Asp Thr Pro Ile Leu Pro Gln
615 620
336 amino acids
amino acid
linear
protein
unknown
8
Ser Arg Thr Ser Leu Leu Leu Ala Phe Gly Leu Leu Cys Leu Pro Trp
1 5 10 15
Leu Gln Glu Gly Ser Ala Asp Ser Val Cys Pro Gln Gly Lys Tyr Ile
20 25 30
His Pro Gln Asn Asn Ser Ile Cys Cys Thr Lys Cys His Lys Gly Thr
35 40 45
Tyr Leu Tyr Asn Asp Cys Pro Gly Pro Gly Gln Asp Thr Asp Cys Arg
50 55 60
Glu Cys Glu Ser Gly Ser Phe Thr Ala Ser Glu Asn His Leu Arg His
65 70 75 80
Cys Leu Ser Cys Ser Lys Cys Arg Lys Glu Met Gly Gln Val Glu Ile
85 90 95
Ser Ser Cys Thr Val Asp Arg Asp Thr Val Cys Gly Cys Arg Lys Asn
100 105 110
Gln Tyr Arg His Tyr Trp Ser Glu Asn Leu Phe Gln Cys Phe Asn Cys
115 120 125
Ser Leu Cys Leu Asn Gly Thr Val His Leu Ser Cys Gln Glu Lys Gln
130 135 140
Asn Thr Val Cys Thr Cys His Ala Gly Phe Phe Leu Arg Glu Asn Glu
145 150 155 160
Cys Val Ser Cys Ser Asn Cys Lys Lys Ser Leu Glu Cys Thr Lys Leu
165 170 175
Cys Leu Pro Gln Ile Glu Asn Val Lys Gly Thr Glu Asp Ser Gly Thr
180 185 190
Thr Ala Gly Ala Gly Pro Arg Cys Arg Pro Ile Asn Ala Thr Leu Ala
195 200 205
Val Glu Lys Glu Gly Cys Pro Val Cys Ile Thr Val Asn Thr Thr Ile
210 215 220
Cys Ala Gly Tyr Cys Pro Thr Met Thr Arg Val Leu Gln Gly Val Leu
225 230 235 240
Pro Ala Leu Pro Gln Val Val Cys Asn Tyr Arg Asp Val Arg Phe Glu
245 250 255
Ser Ile Arg Leu Pro Gly Cys Pro Arg Gly Val Asn Pro Val Val Ser
260 265 270
Tyr Ala Val Ala Leu Ser Cys Gln Cys Ala Leu Cys Arg Arg Ser Thr
275 280 285
Thr Asp Cys Gly Gly Pro Lys Asp His Pro Leu Thr Cys Asp Asp Pro
290 295 300
Arg Phe Gln Asp Ser Ser Ser Ser Lys Ala Pro Pro Pro Ser Leu Pro
305 310 315 320
Ser Pro Ser Arg Leu Pro Gly Pro Ser Asp Thr Pro Ile Leu Pro Gln
325 330 335
6 amino acids
amino acid
single
linear
peptide
unknown
9
Ala Gly Ala Ala Pro Gly
1 5
4 amino acids
amino acid
single
linear
peptide
unknown
10
Ala Gly Ala Gly
1
30 base pairs
nucleic acid
single
linear
cDNA
unknown
11
TTTTCTCGAG ATGGCTACAG GTAAGCGCCC 30
39 base pairs
nucleic acid
single
linear
cDNA
unknown
12
ACCTGGGGCA GCACCGGCAC AGGAGACACA CTCGTTTTC 39
42 base pairs
nucleic acid
single
linear
cDNA
unknown
13
TGTGCCGGTG CTGCCCCAGG TTGCCCAGAA TGCACGCTAC AG 42
36 base pairs
nucleic acid
single
linear
cDNA
unknown
14
TTTTGGATCC TTAAGATTTG TGATAATAAC AAGTAC 36
39 base pairs
nucleic acid
single
linear
cDNA
unknown
15
CCGTGGACCA GCACCAGCAC AGGAGACACA CTCGTTTTC 39
36 base pairs
nucleic acid
single
linear
cDNA
unknown
16
TGTGCTGGTG CTGGTCCACG GTGCCGCCCC ATCAAT 36
32 base pairs
nucleic acid
single
linear
cDNA
unknown
17
TTTTGGATCC TTATTGTGGG AGGATCGGGG TG 32
27 base pairs
nucleic acid
single
linear
cDNA
unknown
18
TTTTAGATCT CTTCTTGCAC AGTGGAC 27
21 base pairs
nucleic acid
single
linear
cDNA
unknown
19
TGTGGTGCCT GAGTCCTCAG T 21
41 base pairs
nucleic acid
single
linear
cDNA
unknown
20
ACTGAGGACT CAGGCACCAC AGCCGGTGCT GCCCCAGGTT G 41
29 base pairs
nucleic acid
single
linear
cDNA
unknown
21
TTTTTCTAGA GAAGCAGCAG CAGCCCATG 29
75 base pairs
nucleic acid
single
linear
cDNA
unknown
22
TTTTCCACAG CCAGGGTGGC ATTGATGGGG CGGCACCGTG GACCAGCACC AGCTGTGGTG 60
CCTGAGTCCT CAGTG 75
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A hybrid protein includes two coexpressed amino acid sequences forming a dimer. Each sequence contains the binding portion of a receptor, such as TBP1 or TBP2, or a ligand, such as IL-6, IFN-βand TPO, linked to a subunit of a heterodimeric proteinaceous hormone, such as hCG. Each coexpressed sequence contains a corresponding hormone subunit so as to form a heterodimer upon expression. Corresponding DNA molecules, expression vectors and host cells are also disclosed as are pharmaceutical compositions and a method of producing such proteins.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present application is a divisional application of U.S. patent application Ser. No. 12/206,579, filed on Sep. 08, 2008, which is hereby incorporated by reference.
[0003] The present invention relates to heat dissipation, more particularly, to an extrusion molding method of forming a heat dissipating structure having enhanced air cooling performance.
[0004] 2. Related Art
[0005] Referring to FIGS. 1A and 1B , an air-cooling heat dissipating structure 1 in the prior art is shown. The air-cooling heat dissipating structure 1 essentially includes a substrate 2 and fins 3 formed on the substrate 2 . The substrate 2 is provided for contacting a heat source, or serves as a casing to enclose a heat generating member. An inner surface of the substrate 2 absorbs heat of a heat source 4 or a heat generating member 5 through heat conduction or heat convection, and an outer surface of the substrate 2 exchanges heat with ambient air to dissipate heat through heat convection. The fins 3 are disposed on the outer surface of the substrate 2 and arranged in parallel. The fins 3 are provided for increasing the total surface area for heat exchange, to enhance the heat convection performance of the air-cooling heat dissipation structure.
[0006] In general, the heat dissipating structure in the prior art is fabricated by various methods, such as machining, die casting, extrusion molding, and combination process. The extrusion molding method is widely applied to fabricate members of a uniform cross-sectional shape, due to its high production rate and simple processes. The extrusion molding method using aluminum or aluminum alloy with a relatively low melting point is also referred to as an aluminum extrusion molding method.
[0007] As aforementioned, the air-cooling heat dissipating structure is applied to serve as a casing to enclose a heat generating member. The heat generated by the heat generating member is indirectly dissipated outside through the air-cooling heat dissipating structure. The heat generating member is also directly cooled by air flowing into the casing to achieve an enhanced heat dissipation performance. In order to allow the circulation of the air flows, air vents formed on the casing are required to improve the air circulation effect.
[0008] However, the extrusion molding method can only be used to fabricate continuous structures having a uniform cross-sectional area. If the extruded direction of the extrusion molding is defined as a longitudinal direction, through-holes penetrating the extrudate in a direction perpendicular to the longitudinal direction cannot be formed by extrusion molding. If it is intended to form air vents by punching processing, the punching tool is unable to punch holes on the substrate 2 due to the fins 3 protruding from the heat dissipating structure 1 . A drill bit can be used to drill holes on the substrate 2 , but only one air vent can be done in each process. When the heat dissipating structure 1 must be studded with air vents, the use of a drill bit for drilling holes may require a lot of processing time, and thus fails to meet the demand on yield. Therefore, an enclosed casing fabricated by an extruded heat dissipating structure can only introduce cooling air flows in and exhaust hot air out through the air vents opened on the front and rear panels thereof, so that it is difficult to promote the circulation of the cooling air flows to enhance the air-cooling effect.
SUMMARY OF THE INVENTION
[0009] In the prior art, the problem that the existence of the fins causes difficulties on rapidly producing ventilated structures. By forming cut channels, the present invention rapidly forms massive cut through slots on a heat dissipating structure that has fins extended outward, thereby enhancing the air-cooling efficiency of the heat dissipating structure.
[0010] In one aspect of the present invention, a heat dissipating structure comprises an extrudate, multiple fins and one or more cut channel. The extrudate includes multiple protruding bent portions extending externally in parallel. The fins extend in parallel with the bent portions. One or more of the fins is disposed on one of the bent portions. The cut channel includes an notch forming on at least one of the fins and a cut-through slot forming on at least one of the bent portions; wherein the notch and the cut-through slot of the cut channel are coplanar.
[0011] In another aspect of the present invention, a method of forming a heat dissipating structure comprises the following steps. First of all, extrude a heat dissipating structure including multiple bent portions and multiple fins. The bent portions protrude outward and are in parallel with the fins. One or more of the fins is disposed on one of the bent portions of the heat dissipating structure. Then, cut the heat dissipating structure to form one or more cut channel. The cut channel includes an notch forming on one or more of the fins and a cut-through slot forming on one or more of the bent portions. It is to be disclosed be the present invention that the notch and the cut-through slot of the cut channel are coplanar.
[0012] These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and appended claims. It is to be understood that both the foregoing general description and the following detailed description are examples, and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The present invention will become more fully understood from the detailed description given herein below for illustration only, and thus is not limitative of the present invention, and wherein:
[0014] FIG. 1A is a cross-sectional view of a heat dissipating structure in the prior art;
[0015] FIG. 1B is a perspective view of a heat dissipating structure in the prior art;
[0016] FIGS. 2 and 3 are perspective views of a heat dissipating structure according to a first embodiment of the present invention;
[0017] FIG. 4 is a top view of the heat dissipating structure according to the first embodiment of the present invention;
[0018] FIG. 5A is a cross- sectional view along line A-A′ in FIGS. 3 and 4 ;
[0019] FIG. 5B is a cross-sectional view along line B-B′ in FIGS. 3 and 4 ;
[0020] FIGS. 6A , 6 B, and 6 C are cross-sectional views of the first embodiment of the present invention, showing steps of forming the heat dissipating structure;
[0021] FIG. 7 is a perspective view of a casing formed according to the first embodiment of the present invention;
[0022] FIGS. 8 and 9 are perspective views of a heat dissipating structure according to a second embodiment of the present invention;
[0023] FIGS. 10 and 11 are cross-sectional views of the second embodiment;
[0024] FIGS. 12 and 13 are cross-sectional views of the second embodiment of the present invention, showing steps of forming the heat dissipating structure;
[0025] FIGS. 14 and 15 are perspective views of a heat dissipating structure according to a third embodiment of the present invention;
[0026] FIGS. 16 and 17 are cross-sectional views of the third embodiment;
[0027] FIGS. 18 , 19 , and 20 are cross-sectional views of the third embodiment of the present invention, showing steps of forming the heat dissipating structure;
[0028] FIG. 21 is a cross-sectional view of a fourth embodiment of the present invention;
[0029] FIG. 22 is a cross-sectional view of a fifth embodiment of the present invention;
[0030] FIG. 23 is a cross-sectional view of a sixth embodiment of the present invention;
[0031] FIG. 24 is a cross-sectional view of a seventh embodiment of the present invention; and
[0032] FIG. 25 is a cross-sectional view of an eighth embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description refers to the same or the like parts.
[0034] Referring to FIGS. 2 , 3 , and 4 , a heat dissipating structure 100 according to a first embodiment of the present invention is shown. The heat dissipating structure 100 includes an extrudate 110 and a plurality of fins 120 , wherein the extrudate 110 and the fins 120 are formed monolithically by extrusion molding, and cooling air can flow through the extrudate 110 to enhance the air-cooling effect.
[0035] FIG. 5A is a cross-sectional view along line A-A′ in FIGS. 3 and 4 . As shown in FIG. 5A , the extrudate 110 is formed by extrusion molding, the extrudate 110 can be a single sheet or a tubular structure. The extrudate 110 includes a plurality of bent portions 111 and a plurality of connecting portions 112 disposed alternately, and the bent portions 111 and connecting portions 112 extend in a longitudinal direction of the extrudate. The connecting portions 112 are provided for connecting the adjacent bent portions 111 , and the bent portions 111 protrude from a surface of the extrudate 110 . Since the extrudate 110 is formed by the extrusion molding, the bent portions 111 extend in parallel along the longitudinal direction of the extrudate 110 . The aforementioned longitudinal direction is a direction which the extrudate 110 is extruded along in the extrusion molding.
[0036] Referring to FIG. 5A , the extrudate 110 and the fins 120 are simultaneously formed by the extrusion molding, wherein the fins 120 are monolithically formed on an outer surface of the extrudate 110 . The fins 20 increase the total surface area for heat dissipation of the heat dissipating structure. Since the fins 120 are formed by extrusion molding and extruded along the longitudinal direction, the fins 120 continuously extend in parallel with the bent portions 111 and the connecting portions 112 . The fins 120 are respectively disposed on the bent portions 111 and the connecting portions 112 .
[0037] FIG. 5B is a cross-sectional view along line B-B′ in FIGS. 3 and 4 . As shown in FIG. 5B , after monolithically forming the extrudate 110 and the fins 120 by extrusion, a cutting process is performed. The extrudate 110 and the fins 120 of the heat dissipating structure 100 are cut by a cutting tool 900 to form a plurality of cut channels 130 . The cutting direction of the cut channel 130 males an angle with respect to the longitudinal direction of the extrudate 110 , namely, the cutting direction is not in parallel with the longitudinal direction of the extrudate 110 . Each cut channel 130 respectively forms an notch 131 on each fin 120 and meanwhile form a cut-through slot 132 on each bent portion 111 .
[0038] Referring to FIGS. 6A , 6 B, and 6 C, each cut channel 130 is formed by the cutting tool 900 cutting in a straight line with a gradually increasing cutting depth D, wherein the cutting depth D is the feed travel of the cutting tool 900 toward the extrudate 110 . In each cut channel 130 , the notch 131 and the cut-through slot 132 are formed by a single motion of the same cutting tool 900 , so that the notch 131 and the cut-through slot 132 are coplanar. As the fins 120 are formed on the surface of the extrudate 110 and with front edges located outside the top edges of the bent portions 111 , the cutting tool 900 will cut the fins 120 in advance when fed toward the surface of the extrudate 110 , thus forming the notches 131 on the fins 120 .
[0039] Then, the cutting tool 900 is brought into contact with the top edges of the bent portions 111 and cuts the bent portions 111 , so as to form the cut-through slots 132 on the bent portions 111 . The feed travel from the point that the cutting tool 900 is brought into contact with the top edges of the bent portions 111 to a point that the feeding of the cutting tool 900 is stopped is regarded as the cutting depth D. Such a cutting depth D is also equal to a distance from the outermost to the innermost edge of the cut-through slot 132 . In order to prevent the cut channels 130 formed by the cutting tool 900 from cutting off the extrudate 110 , junctions between the adjacent bent portions 111 are required to reserved. In this embodiment, the junctions between the adjacent bent portions 111 are the connecting portions 112 , such that the cutting tool 900 may not cut off the connecting portions 112 . That is, the cutting depth D of each cut-through slot 132 is smaller than the height of the bent portion 111 protruding from the connecting portion 112 , so as to prevent the connecting portion 112 from being cut off by the cutting tool 900 .
[0040] If bottom edges of the cut channels 130 are defined as cutting lines, a minimum cutting line Hmin can be defined at the highest point of the inner side faces of the bent portions 111 , and a maximum cutting line Hmax can be defined on the top faces of the connecting portions 112 . Cutting lines formed by the cutting tool 900 on the extrudate 110 lie between the minimum cutting line Hmin and the maximum cutting line Hmax, such that the cut-through slots 132 can be formed by the cutting tool 900 on the bent portions 111 without cutting off the connecting portions 112 .
[0041] The cut channels 130 are formed by the single cutting tool 900 to rapidly form the cut-through slots 132 on the extrudate 110 for the cooling air flows to pass through. Since, the cooling air flows can quickly flow through the extrudate 110 , the convection heat transfer is enhanced.
[0042] Referring to FIG. 7 , the heat dissipating structure 100 can be fabricated into an enclosed or semi-enclosed casing. For example, the heat dissipating structure 100 is fabricated into a tubular structure surrounded by a plate and used as a casing of an electronic apparatus. In the heat dissipating structure 100 , heat is absorbed through the inner side face of the extrudate 110 , and dissipated through the outer surface thereof and the fins 120 . Meanwhile, the cut-through slots 132 allow the air flows to directly pass through the heat dissipating structure 100 , thus enhancing the heat dissipation effect.
[0043] FIGS. 8 , 9 , 10 , and 11 a heat dissipating structure 200 according to a second embodiment of the present invention is shown. The heat dissipating structure 200 includes an extrudate 210 and a plurality of fins 220 , wherein the extrudate 210 and the fins 220 are monolithically formed by extrusion molding. The extrudate 210 includes a plurality of bent portions 211 and a plurality of connecting portions 212 disposed alternately, and the bent portions 211 and connecting portions 212 extend in a longitudinal direction. The connecting portions 212 are provided for connecting the adjacent bent portions 211 , and the bent portions 211 protrude from a surface of the extrudate 210 . The bent portion 211 includes a first protruding portion 2111 and a second protruding portion 2112 adjacent to each other on the cross-section, wherein the height of the first protruding portion 2111 protruding from the connecting portions 212 is larger than that of the second protruding portion 2112 protruding from the connecting portions 212 . The fins 220 are disposed in parallel with the bent portions 211 , and are respectively disposed on the bent portions 211 and the connecting portions 212 . The fins 220 on the bent portions 211 are disposed on the first protruding portions 2111 , or the second protruding portions 2112 .
[0044] Referring to FIGS. 12 and 13 , the heights of the cutting lines of cut channels 230 determine whether cut-through slots 232 can be formed as well as cutting depths D of the formed cut-through slots 232 . In the second embodiment, the heights of the cutting lines further determine the range of forming the cut-through slots 232 .
[0045] Referring to FIG. 12 , when reaching a first cutting line H 1 , the edge of the cutting tool 900 is located between the top edges of the first protruding portions 2111 and the second protruding portions 2112 , and only the first protruding portions 2111 is cut by the cutting tool 900 . At this point, the cut-through slots 232 are formed on the first protruding portions 2111 .
[0046] Referring to FIG. 13 , when reaching a second cutting line H 2 , the edge of the cutting tool 900 passes through the top edges of the first protruding portions 2111 and the second protruding portions 2112 , and both the first protruding portions 2111 and the second protruding portions 2112 are cut. At this point, the cut-through slots 232 are formed on the first protruding portions 2111 and further extend to the second protruding portions 2112 , thereby enhancing the overall porosity of the cut-through slots 232 .
[0047] Referring to FIGS. 14 , 15 , 16 , and 17 , a heat dissipating structure 300 according to a third embodiment of the present invention is shown. The heat dissipating structure 300 , similar to that of the first embodiment, includes an extrudate 310 and a plurality of fins 320 , wherein the extrudate 310 and the fins 320 are formed monolithically. The extrudate 310 includes a plurality of bent portions and a plurality of connecting portions 312 disposed alternately, and the bent portions and the connecting portions 312 extend in a longitudinal direction of the extrudade 310 . The connecting portions 312 are provided for connecting the adjacent bent portions, and the bent portions protrude from a surface of the extrudate 310 . The heights of the bent portions protruding from the connecting portions 312 are unequal. The fins 320 are in parallel with the bent portions, and are respectively disposed on the bent portions and the connecting portions 312 .
[0048] Referring to FIGS. 18 , 19 , and 20 , the heights of the cutting lines of cut channels 330 determine whether cut-through slots 332 are formed at the bent portions by the cutting tool 900 as well as the cutting depths of the cut-through slots 332 . The heights of the bent portions are unequal. When the cutting tool 900 is fed toward the surface of the extrudate 310 , the fins 320 are cut at first, then the bent portions having relative higher height are cut to form the cut-through slots 332 , and afterward the bent portions 311 having relative lower height are cut. In the third embodiment, the bent portions at least include a first bent portion 3111 , a second bent portion 3112 , and a third bent portion 3113 . The first bent portion 3111 , the second bent portion 3112 , and the third bent portion 3113 are designated for illustration, instead of limiting the number of the bent portions.
[0049] Referring to FIG. 18 , when the cutting tool 900 is continuously fed to make the cutting depths of the cut channels 330 reach a first cutting line H 1 , in addition to forming the notches 331 on the fins 320 , only the first bent portion 3111 , on which has the highest height, is cut to form cut-through slots 332 .
[0050] Referring to FIG. 19 , when the cutting tool 900 is continuously fed to make the cutting depths of the cut channels 330 reach a second cutting line H 2 , the cut channels 330 simultaneously penetrate the first bent portion 3111 and the second bent portion 3112 to form the cut-through slots 332 .
[0051] Referring to FIG. 20 , when the cutting tool 900 is continuously fed to make the cutting depths of the cut channels 330 reach a third cutting line H 3 , the first bent portion 3111 , the second bent portion 3112 , and the third bent portion 3113 are all cut to form the cut-through slots 332 .
[0052] In the present invention, it is not necessary for forming cut-through slots at all the bent portions. Whether the cut-through slots are formed or not depends on the cutting depths of the cut channels and the heights of the bent portions. According to the third embodiment, the number of the cut-through slots to be formed is determined by the cutting depths and the height differences of the bent portions.
[0053] In the first to the third embodiment, the cross-sectional area of the bent portions are approximately rectangular (in the first and third embodiments) or a combination of a plurality of rectangles (in the second embodiment). However, the cross-sectional areas of the bent portions are not limited to be rectangular, but can be of any shape protruding from the extrudate. The shape of the cross-sectional area of the bent portion is determined according to the consideration whether it can be easily extrusion-molded.
[0054] Referring to FIG. 21 , a heat dissipating structure 400 according to a fourth embodiment of the present invention is shown. The heat dissipating structure 400 includes an extrudate 410 and a plurality of fins 420 , wherein the extrudate 410 and the fins 420 are monolithically formed. The extrudate 410 includes a plurality of bent portions 411 and a plurality of connecting portions 412 , the bent portion 411 and connecting portion 412 are disposed alternately and extend in a longitudinal direction of the extrudate 410 . The connecting portions 412 are provided for connecting the adjacent bent portions 411 , and the bent portions 411 protrude from a surface of the extrudate 410 . The fins 420 are disposed in parallel with the bent portions 411 , and are respectively disposed on the bent portions 411 and the connecting portions 412 . In the fourth embodiment, the cross-sectional areas of the bent portions 411 are quadrangular of any form.
[0055] Referring to FIGS. 22 and 23 , a heat dissipating structure 500 according to a fifth embodiment and a heat dissipating structure 600 according to a sixth embodiment of the present invention are shown. The heat dissipating structure 500 , 600 includes an extrudate 510 , 610 and a plurality of fins 520 , 620 , wherein the extrudates 510 , 610 are monolithically formed with the fins 520 , 620 . The extrudate 510 , 610 includes a plurality of bent portions 511 , 611 and a plurality of connecting portions 512 , 612 . In the fifth and sixth embodiments, the cross-sectional areas of the bent portions 511 and 611 are respectively arc-shaped and triangular.
[0056] Referring to FIG. 24 , a heat dissipating structure 700 according to a seventh embodiment of the present invention is shown. The heat dissipating structure 700 includes an extrudate 710 and a plurality of fins 720 , wherein the extrudate 710 and the fins 720 are monolithically formed. The extrudate 710 includes a plurality of protruding bent portions 711 in parallel with each other. The cross-sectional areas of the bent portions 711 are triangular.
[0057] The adjacent bent portions 711 are connected to each other at edges. The fins 720 are formed on the bent portions 711 , or on joining portions between the adjacent bent portions 711 . Therefore, when the cutting tool is used to form cut channels, junctions 711 a between the adjacent bent portions 711 are required to be reserved. A minimum cutting line Hmin is defined at the highest point of the inner surface of the bent portions 711 , and a maximum cutting depth Hmax is defined at the lowest point of the outer surfaces of the bent portions 711 . The cutting lines for the cutting tool to cut the bent portions 711 lies between the minimum cutting depth Hmin and the maximum cutting depth Hmax, such that cut-through slots 732 are formed on the bent portions 711 without cutting off the junctions 711 a between the adjacent bent portions 711 .
[0058] Referring to FIG. 25 , a heat dissipating structure 800 according to an eighth embodiment of the present invention is shown. The heat dissipating structure 800 is similar to that of the seventh embodiment, and only differs in that the cross-sectional areas of the bent portions 811 of the eighth embodiment are arc-shaped.
[0059] Additional advantages and modifications will readily occur to those proficient in the relevant fields. The invention in its broader aspects is therefore not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
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A forming method for a heat dissipating structure is provided. According to the method, an extrudate is formed by extrution molding, wherein the extrudate includes protruding bending portions extending in parallel. Fins are extruded monolithically on the bending portions. One or more cut channels are formed by cutting the fins and the extrudate with a cutting tool. The cutting tool cuts the fins for forming a notch on each fin at first, and then cuts the bending portions for forming a cut-through slot on each bending portion, wherein each cut-through slot is formed for cooling air flowing through two side of the extrudate. By cutting the bending portions and the fins by the cutting tool at the same time, a large number of cut-through slots are formed in despite of the existence of the fins, and the performance of heat dissipation is enhanced.
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BACKGROUND OF THE INVENTION
This invention relates to a composition and method of use thereof for treating cancer. More particularly, the invention relates to a bicyclic depsipeptide, vitilevuamide, which has anticancer activity, and a method of use thereof for treating cancer in an individual in need thereof.
Marine organisms, especially invertebrates such as ascidians, sponges, soft corals, and mollusks, produce many secondary metabolites that are not found in the terrestrial world. Recent studies in the field of marine natural products have focused on detection of biomedically important compounds. This research has resulted in the discovery of compounds that have anticancer, antiviral, and antiinflammatory activity. CNS membrane-active toxins, ion channel effectors, and metabolites that interact with DNA and micro-filament processes have also been identified.
Each phylum produces a characteristic distribution of compounds. For example, in the years 1977 to 1985, 85% of the metabolites isolated from coelenterates were terpenoids; 37% and 41% of compounds isolated from sponges were terpenoids and nitrogenous metabolites, respectively; and 89% of compounds isolated from ascidians were nitrogenous compounds, such as amino acid derivatives. C. M. Ireland et al., 13 Proc. Calif. Acad. Sci. 41 (1987).
The birth of the field of marine natural products was marked with the isolation of several modified arabino nucleosides from the sponge, Cryptoethya crypta. W. Bergann & R. J. Feeney, 72 J. Am. Chem. Soc. 2809 (1950). The first ascidian metabolite, geranyl hydroquinone, was isolated in 1974 from Aplidium sp. W. Fenical, 1974 Food-Drugs Sea 388 (1976). This compound exhibited activity against some forms of leukemia, Rous sarcoma, and mammary carcinoma in test animals. Since then, ascidians have been targeted for the specific purpose of isolating compounds of biomedical importance. Between 1988 and 1992, about 165 new ascidian metabolites were discovered. C. M. Ireland et al., in D. G. Fautin ed., 13 Biomedical Importance of Marine Organisms 41 (1988).
Peptides are one of the major structural classes of compounds isolated from ascidians. Ulicylamide and ulithiacyclamide were the first of a series of cyclic peptides isolated from Lissoclinum patella. C. M. Ireland & P. J. Scheuer, 102 J. Am. Chem. Soc. 5688 (1980). The genus Lissoclinum has proven to be a prolific producer of two classes of cyclic peptides, the heptapeptide lissoclinamides and the octapeptide patellamides/ulithiacyclamides. Each of these classes is characterized by the presence of thiazole and oxazoline amino acids. These peptides exhibit in vitro toxin activity, with the presence of the oxazoline ring proving important to their potency. T. Shioiri et al., 36 Biochem. Pharmacol. 4181 (1987).
The first metabolite from an ascidian to enter phase III clinical trials was didemnin B, a cyclic depsipeptide isolated from the Caribbean ascidian, Trididemnum solidum. K. L. Rinehart et al., 212 J. Am. Chem. Soc. 933 (1981); K. L. Rinehart et al., 212 Science 933 (1981). Didemnins A, B, and C were first isolated in 1981 and were proposed to contain the unique structural unit, hydroxyisovalerylpropionate (HIP), and a new allo stereoisomer of statine. K. L. Rinehart et al., 109 J. Am. Chem. Soc. 6846 (1987). These didemnins were found to inhibit Herpes simplex viruses I and II, Rift Valley Fever virus, Venezuelan equine encephalitis virus, and yellow fever virus. Didemnin H, A. Boulanger et al., 35 Tetrahedron Lett. 4345 (1994), was found to interact with DNA. J. M. Pezzuto et al., 54 J. Nat'l Prod. 1522 (1991).
Cancer is the leading cause of death in many countries. In the United States and Canada, only diseases of the heart and blood vessels kill more people. About 100 kinds of cancer attack human beings. Drug therapy or chemotherapy is an important method of treating such cancers. More than 50 drugs are used against a variety of cancers, and such drugs have proven especially effective in treating leukemia and lymphoma. Anticancer drugs are designed to destroy cancer cells with as little injury to normal cells as possible. Nevertheless, the drugs tend to injure normal cells to some degree and thus produce various undesirable side effects, ranging from nausea to high blood pressure. There is a need to develop new anticancer drugs that are effective against various kinds of cancers and that are less harmful to normal cells.
In view of the foregoing, it will be appreciated that providing a new antitumor drug and a method of use thereof for treating cancerous tumors would be a significant advancement in the art.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide a new anticancer drug.
It is another object of the invention to provide a method of treating cancer in a person in need thereof.
It is also an object of the invention to provide a method of purifying vitilevuamide.
These and other objects can be achieved by providing a purified compound selected from the group consisting of vitilevuamide and pharmaceutically acceptable salts thereof. Preferably, the purified compound is vitilevuamide.
A composition for treating cancer comprises an effective amount of an anticancer agent selected from the group consisting of vitilevuamide, pharmaceutically acceptable salts thereof, and mixtures thereof; and an inert carrier. Preferably, the anticancer agent is vitilevuamide. The composition can also further comprise a member selected from the group consisting of excipients, wetting agents, emulsifying agents, and buffers.
A method for purifying vitilevuamide comprises the steps of:
(a) collecting specimens of an ascidian selected from the group consisting of Didemnum cuculliferum and Polysyncraton lithostrotum;
(b) repeatedly extracting the specimens with methanol to yield a crude homogenate;
(c) separating the crude homogenate into fractions of increasing polarity by extracting first with hexanes and then with chloroform to yield a chloroform extract;
(d) subjecting the chloroform extract to a first silica gel flash chromatography step with stepped gradient elution with chloroform, 99:1 chloroform/methanol, and then 98:2 chloroform/methanol to obtain a 98:2 chloroform/methanol eluant;
(e) subjecting the 98:2 chloroform/methanol eluant to a second silica gel flash chromatography step with stepped gradient elution with 3:7 acetone/hexanes, and then 7:3 acetone/hexanes to yield a 7:3 acetone/hexanes fraction; and
(f) subjecting the 7:3 acetone/hexanes fraction to reverse phase HPLC with a mobile phase of 9:1 CH 3 CN/H 2 O such that a fraction is separated therefrom comprising a bicyclic peptide with a molecular weight of about 1603.8.
Another method for purifying vitilevuamide comprises the steps of:
(a) collecting specimens of an ascidian selected from the group consisting of Didemnum cuculliferum and Polysyncraton lithostrotum;
(b) repeatedly extracting the specimens with methanol to yield a crude homogenate;
(c) separating the crude homogenate into fractions of increasing polarity by extracting first with hexanes and then with chloroform to yield a chloroform extract;
(d) subjecting the chloroform extract to silica gel flash chromatography with stepped gradient elution with chloroform, 99:1 chloroform/methanol, and then 98:2 chloroform/methanol to obtain a 98:2 chloroform/methanol eluant;
(e) subjecting the 98:2 chloroform/methanol eluant to reverse phase flash chromatography with stepped gradient elution with H 2 O, 50% methanol/H 2 O, 70% methanol/H 2 O, 80% methanol/H 2 O, and 90% methanol/H 2 O to obtain a 90% methanol/H 2 O eluant; and
(f) subjecting the 90% methanol/H 2 O eluant to amino flash chromatograph with stepped gradient elution with chloroform and then 2.5% methanol/chloroform to obtain a 2.5% methanol/chloroform eluant comprising a bicyclic peptide with a molecular weight of about 1603.8.
A method for treating cancer in an individual in need of such treatment comprises administering a composition comprising an effective amount of an anticancer agent selected from the group consisting of vitilevuamide, pharmaceutically acceptable salts thereof, and mixtures thereof; and an inert carrier. Preferably, the anticancer agent is vitilevuamide. The composition can also comprise a member selected from the group consisting of excipients, wetting agents, emulsifying agents, and buffers. The composition is preferably administered by systemic administration.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 shows the structure of the bicyclic depsipeptide, vitilevuamide.
FIG. 2 shows the major fragmentation pattern of vitilevuamide upon tandem mass spectroscopy for sequential analysis.
FIG. 3 shows the fractional survival of HCT 116 tumor cells as a function of dose of vitilevuamide.
FIG. 4 shows the fractional survival of A549 tumor cells as a function of dose of vitilevuamide.
FIG. 5 shows the fractional survival of SK-MEL-5 tumor cells as a function of dose of vitilevuamide.
FIG. 6 shows the fractional survival of A498 tumor cells as a function of dose of vitilevuamide.
FIG. 7 shows the absorbance of C6 rat glioma cells treated with vitilevuamide expressed as a function of the absorbance of such cells treated with 25 μg/mL of colchicine.
DETAILED DESCRIPTION
Before the present antitumor composition and method of use thereof are disclosed and described, it is to be understood that this invention is not limited to the particular configurations, process steps, and materials disclosed herein as such configurations, process steps, and materials may vary somewhat. It is also to be understood that the terminology employed herein is used 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 and equivalents thereof.
It must be noted that, as used in this specification and 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 composition containing "an excipient" includes reference to two or more of such excipients, reference to "an emulsifying agent" includes reference to one or more of such agents, and reference to "a wetting agent" includes reference to two or more of such wetting agents.
In describing and claiming the present invention, the following terminology will be used in accordance with the definitions set out below.
As used herein, such a "pharmaceutically acceptable" component is one which is suitable for use with humans and/or animals without undue adverse side effects (such as toxicity, irritation, and allergic response) commensurate with a reasonable benefit/risk ratio.
As used herein, "effective amount" means an amount of an anticancer agent that is nontoxic but sufficient to provide the desired effect and performance against cancer cells at a reasonable benefit/risk ratio attending any medical treatment.
As used herein, "administering" and similar terms mean delivering the compound or composition to the individual being treated such that the compound or composition is capable of being circulated systemically to the parts of the body where the anticancer agent can act on cancer cells. Thus, the composition is preferably administered to the individual by systemic administration, typically by subcutaneous, intramuscular, or intravenous administration, or intraperitoneal administration. Injectables for such use can be prepared in conventional forms, either as a liquid solution or suspension or in a solid form suitable for preparation as a solution or suspension in a liquid prior to injection, or as an emulsion. Suitable excipients include, for example, water, saline, dextrose, glycerol, ethanol, and the like; and if desired, minor amounts of auxiliary substances such as wetting or emulsifying agents, buffers, and the like can be added.
EXAMPLE 1
Extraction and Isolation Procedures
Specimens of Didemnum cuculliferum were collected at Namenalala Island, Fiji, and kept frozen until extracted. The methanol extract of the frozen tunicate (350 grams) was repeatedly extracted with 2.5 L of methanol. The crude homogenate (reduced to 50 mL) was separated into increasing polar fractions by extracting first with hexanes (3×500 mL) and chloroform (5×500 mL) using a modified Kupchan solvent partitioning scheme, S. M. Kupchan et al., 38 J. Org. Chem. 178 (1973), hereby incorporated by reference.
The resulting 325.1 mg of chloroform extract was subjected to silica gel flash chromatography in a 2.8×46 cm column packed with 60 Å, 35-70 μm silica support. Elution was by stepped gradient elution with the following eluants: CHCl 3 ; 99:1 CHCl 3 /MeOH; 98:2 CHCl 3 /MeOH; 97.5:2.5 CHCl 3 /MeOH. The active factor eluted in the 98:2 CHCl 3 /MeOH fraction. The eluted material was subjected to a second silica gel flash chromatography step with stepped gradient elution with the following eluants: 3:7 acetone/hexanes; 7:3 acetone/hexanes; acetone.
The 70% acetone/hexanes fraction was subjected to reverse phase HPLC using a C-18 Rainin Microsorb 0.5×25 cm column with 100 Å, 5 μm silica gel. Elution in 90% CH 3 CN/10% H 2 O and UV detection at 220 nm yielded 10.2 mg of a clear glassy compound, the new cyclic peptide vitilevuamide (FIG. 1).
EXAMPLE 2
Extraction and Isolation Procedures
Specimens of Polysyncraton lithostrotum were collected at Namenalala Island, Fiji, and kept frozen until extracted. The methanol extract of the frozen tunicate (350 grams) was repeatedly extracted with 2.5 L of methanol. The crude homogenate (reduced to 50 mL) was separated into increasing polar fractions by extracting first with hexanes (3×500 mL) and chloroform (5×500 mL) using a modified Kupchan solvent partitioning scheme, S. M. Kupchan et al., 38 J. Org. Chem. 178 (1973), hereby incorporated by reference.
The resulting chloroform extract was subjected to silica gel flash chromatography in a 2.8×46 cm column packed with 60 Å, 35-70 μm silica support. Elution was by stepped gradient elution with the following eluants: CHCl 3 ; 99:1 CHCl 3 /MeOH; 98:2 CHCl 3 /MeOH; 97.5:2.5 CHCl 3 /MeOH. The active factor eluted in the 98:2 CHCl 3 /MeOH fraction. Reverse phase flash chromatography was then performed (28 mm I.D.×46 mm column) with LiChroprep RP-18, 40-63 μm, using stepped gradient elution in, successively, 100% H 2 O, 50% MeOH in H 2 O, 70% MeOH in H 2 O, 80% MeOH in H 2 O, and 90% MeOH in H 2 O, with the vitelevuamide eluting in the 90% MeOH/H 2 O fraction. This fraction was then subjected to amino flash chromatography using Bakerbond amino, 40 μm, solid support in a 28 mm I.D.×46 mm column, with stepped gradient elution in 100% chloroform followed by 2.5% MeOH in chloroform, with 12.5 mg of vitilevuamide eluting in the 5% MeOH/CHCl 3 fraction.
EXAMPLE 3
In this example, vitilevuamide is purified from specimens of Polysyncraton lithostrotum according to the procedure of Example 1.
EXAMPLE 4
In this example, vitilevuamide is purified from specimens of Didemnum cuculliferum according to the procedures of Example 2.
EXAMPLE 5
High Resolution Mass Spectrometry
High resolution mass measurements of vitilevuamide prepared according to the procedures of Examples 1 or 2 were made on a ZAB-SE or a Varian MAT-731 mass spectrometer. The high resolution fast atom bombardment mass spectrum showed a protonated molecular ion at m/z 1603.811768, in good agreement with a molecular formula of C 77 H 114 N 14 O 21 S (Δ1.0 mmu).
EXAMPLE 6
IR and UV Spectroscopy
Infra red (IR) spectra of vitilevuamide prepared according to the procedures of Examples 1 or 2 were recorded with a Perkin-Elmer 1600 FT spectrophotometer using a thin film of vitilevuamide on sodium chloride plates. Ultraviolet (UV) spectra were recorded with a Hewlett-Packard HP8452A spectrophotometer.
IR bands at 3280, 1652, 1558, and 1538 cm -1 (amide I and II) were indicative of HN and carbonyl stretches for peptides. These results were further evidence that vitilevuamide is a peptide. The absence of IR bands corresponding to an ammonium ion and the presence of an ester carbonyl band at 1734 cm -1 suggested that vitilevuamide was cyclic or had terminal end modifications. Both proved correct when the structural components of vitilevuamide accounted for all but two degrees of unsaturation required by the molecular formula.
Ultraviolet (UV) spectroscopy of vitilevuamide showed an absorption at 230 nm with an extinction coefficient of 2032. Weaker absorption maxima were observed at 210 nm (ε=1719) and 250 nm (ε=1985).
EXAMPLE 7
NMR Analysis
1 H and 13 C experiments were conducted at 500 and 200 MHz, respectively, on a Varian Unity spectrometer or an IBM AF 200 spectrometer at 200 and 50 MHz, respectively. Variable temperature studies were performed at -20, -15, -10, -5, 0, 5, 10, 15, 20, 25, 30 and 35° C. using CD 2 Cl 2 , CDCl 3 and C 6 D 6 . Based on these results, all chemical shifts were determined in benzene at 22° C. 1 H chemical shifts are shown herein in ppm relative to undeuterated benzene resonance at 7.15 ppm. 13 C chemical shifts are shown in ppm relative to solvent resonance at 128 ppm.
The 13 C NMR spectrum of vitilevuamide contains 70 resonances, 7 of which represent two carbons each. The degenerate resonances include a carbonyl at 173.28; aromatic carbons at 130.24, 130.05, 128.89 and 128.72; and α-carbons at 57.03 and 55.51 ppm.
A DEPT (distortionless enhancement of polarization transfer) experiment, M. H. Levitt et al., 94 Chem. Phys. Lett. 540 (1983); T. T. Nahkashima et al., 57 J. Mag. Reson. 149 (1984); T. T. Nahkashima et al., 59 J. Mag. Reson. 124 (1984), established the number of protons attached to each carbon, while an HMQC (heteronuclear multiple quantum coherence) experiment, A. Bax & S. Subramanian, 69 J. Mag. Reson. 565 (1986); L. Muller, 101 J. Am. Chem. Soc. 4481 (1979), permitted assignment of the attached protons. Characteristic peptide resonances in the 1 H NMR spectrum included 11 doublets between 10.49 and 6.40 ppm and a singlet at 10.11 attributable to amide NH protons and multiplets between 5.67 and 4.81 ppm corresponding to peptide α protons.
A DQF-COSY (double quantum filter correlated spectroscopy) experiment, U. Piantini et al., 104 J. Am. Chem. Soc. 6800 (1982); M. Rance et al., 117 Biochem. Biophys. Res. Commun. 458 (1983), established the presence of two phenylalanines, valine, threonine, serine, isoleucine, alanine, proline, dehydroalanine, two homoisoleucines and N-methyl-methoxinine residues. A characteristic feature of this peptide is an ester link between the oxygen of threonine and the carbonyl of serine. This was evident from a 3 bond correlation between the β proton of threonine (5.50 ppm) and the carbonyl of serine at 169.851 ppm in an HMBC (heteronuclear multiple bond correlation) experiment (J=8 Hz), M. F. Summers et al., 108 J. Am. Chem. Soc. 4285 (1986).
Evidence for lanthionine was derived from an HMBC experiment. The 2.01 ppm β proton of one half of the lanthionine residue showed a 3 bond connectivity to carbons at 51.02 ppm (own α carbon) and 39.67 ppm (β carbon of the second half). Similarly, the 2.58 ppm β proton of the second half of the lanthionine residue showed a three bond connectivity to the β carbon (32.07 ppm) of the first half.
The terminal succinate was detected by using a combination of DQF COSY, HMQC and HMBC. COSY and TOCSY (total correlation spectroscopy), L. Braunschweiler & R. R. Ernst, 53 J. Mag. Reson. 521 (1983); A. Bax & D. G. Davis, 53 J. Mag. Reson. 521 (1985), verified the connectivity between protons at 1.68, 3.38 ppm ( 13 C at 30.59 ppm) and 1.78, 2.28 ppm ( 13 C at 28.61 ppm). HMBC experiments showed long range coupling between the protons at 2.28 ppm and 1.78 ppm and both carbonyls at 176.87 ppm and 173.28 ppm.
Table 1 contains the complete NMR assignments for vitilevuamide.
TABLE 1______________________________________Atom HMBCNo. δ .sup.13 C (mult.) δ .sup.1 H (mult., J(Hz)) correlations______________________________________N1 8.66 (d, 8.79) C141 170.09 (s)2 54.77 (d) 5.06 (ddd, 2.47, 2.58, C13, C14 5.05)3 63.60 (t) 3.91 (dd, 2.47, 11.48) C13 4.33 (m)4 169.32 (s)5 57.03 (d) 5.68 (d, 5.86) C5, C14, C516 68.05 (t) 4.31 (m)7 70.17 (t) 3.61 (m) 3.45 (m)8 58.65 (q) 3.09 (s)9 32.49 (q) 3.40 (s) C5OH 3.77 (d, 4.44)N3 8.12 (d, 6.90) C4, C35, C5510 173.63 (s)11 56.63 (d) 4.42 (m)12 30.58 (d) 2.26 (bm)13 19.12 (q) 1.03 (bm)14 18.95 (q) 0.93 (bm) C35, C55, C66N4 8.09 (d, 10.66) C1, C4515 175.07 (s)16 54.09 (d) 5.27 (ddd, 4.46, 10.45)17 42.77 (t) 2.29 (bm) C1, C54, C67 1.80 (bm)18 30.29 (d) 2.17 (m)19 18.72 (q) 1.10 (d, 6.78)20 30.74 (t) 1.48 (bm) 1.28 (bm)21 11.55 (q) 0.93 (bm)N5 10.11 (s) C8, C1522 168.26 (s)23 140.21 (s)24 111.11 (t) 4.71 (s) C8, C15, C16 4.83 (S)N6 8.00 (d, 5.23) C7, C31, C4825 172.49 (s)26 60.92 (d) 4.19 (bm) C10, C4827 36.94 (d) 1.89 (bm)27 11.55 (q) 0.93 (bm)28 15.01 (q) 1.21 (d, 6.76)29 25.10 (t) 1.78 (bm) 1.31 (bm)30 10.90 (q) 0.84 (bm)31 172.84 (s)32 50.94 (d) 4.79 (dd, 7.17, 9.59) C7, C4733 31.95 (t) 3.16 (bs) 2.01 (dd, 15.34, 17.38) C734 174.99 (s)35 61.42 (d) 5.16 (dd, 7.6, 15.1) C2, C6136 29.95 (t) 1.94 (bm) C2, C44 1.79 (bm)37 25.11 (t) 1.61 (bm) 1.44 (bm) C3038 47.01 (t) 3.20 (bm) 2.35 (bm)N9 10.49 (d, 4.95) C1139 169.96 (s)40 55.40 (d) 4.31 (m) C11, C4941 37.13 (t) 3.21 (bm) C13, C17, C19, C37 3.05 (bs) C13, C17, C19, C3742 136.28 (s)43 130.12 (d) 7.41 (d, 7.38) C2344 128.89 (d) 7.28 (m) C17, C1845 127.57 (d) 7.08 (d, 7.37) C1946 128.89 (d) 7.28 (m) C17, C1847 130.12 (d) 7.41 (d, 7.38) C23N10 8.72 (d, 6.26) C3, C1148 170.14 (s)49 57.03 (d) 4.95 (dd, 1.12, 6.32) C3, C11, C2750 73.25 (d) 5.51 (ddd, 1.23, 5.86, C13 6.49)51 19.94 (q) 1.14 (d, 6.69)N11 9.22 (d, 9.87) C3, C1052 174.94 (s)53 49.81 (d) 5.62 (ddd, 3.35, 10.05, 10.89)54 42.29 (t) 1.97 (m) C3 1.87 (bm)55 31.83 (d) 1.78 (m)56 13.39 (q) 1.15 (d, 6.56)57 27.78 (t) 1.93 (bm) 1.40 (bm)58 11.22 (q) 1.03 (bm)N12 8.40 (d, 10.43) C659 171.49 (s)60 48.60 (d) 5.40 (q, 6.7, 10.47)61 30.15 (d) 1.35 (bm) C10, C43N13 6.43 (d, 7.78) C6, C9, C38, C5062 173.28 (s)67 128.39 (d) 7.28 (m)68 127.00 (d) 7.10 (d, 7.58)69 128.39 (d) 7.28 (m)70 129.82 (d) 7.50 (d, 7.38)N14 6.54 (d, 8.22) C671 172.54 (s)72 55.40 (d) 4.44 (bm)73 39.48 (t) 3.33 (m) 2.59 (dd, 11.66, 14.21) C2, C36, C5274 173.28 (s)75 30.41 (t) 3.38 (bm) 1.8676 28.61 (t) 2.29 (bm) 1.78 (bm)77 176.82 (s)______________________________________
EXAMPLE 8
Mass Spectrometry Analysis
Electrospray tandem mass spectrometry was instrumental in putting together the fragments isolated and identified via NMR. Vitilevuamide (1.2 mg in methanol) prepared according to the procedure of Examples 1 or 2 was ammoniolysed by adding 1.5 ml of saturated NH 3 in HPLC grade methanol. The resulting solution was chilled at 0° C. for 18 hours. The resulting mixture was then subjected to reverse phase HPLC in a Waters NOVAPAK C 18 column (4.6×100 mm) with isocratic elution in 90% MeOH/H 2 O to isolate the partially linear peptide. Mild acidic or basic hydrolysis of vitilevuamide to cleave the deydroamino acid unit gave very poor yields of the corresponding partially linear peptide and resulted in decomposition.
The partially linear peptide was analyzed by electrospray mass spectrometry on a Fissons Trio 2000 electrospray mass spectrometer, which established a molecular formula of 1620.8, in good agreement (after subtracting the mass of ammonia, m/z=17) with the mass determined in Example 5.
EXAMPLE 9
The partially linearized molecule of Example 8 was subjected to tandem mass spectroscopy for sequential analysis. Tandem mass spectroscopy (MS/MS) was performed on the SIAX API III spectrometer. Five μl of sample was dissolved in 190 μl of H 2 O:CH 3 OH:CH 3 COOH (50:50:1) at a flow rate of 2 μl/min.
The major fragmentation pattern (FIG. 2) shows sequential losses from the amidated C-terminus to produce mass-to-charge ratios (m/z) of 1603.9, 1518, 1372.1, 1272.8, 1145.6, 1076.5, and 963.5. These results correspond with the successive losses of ammonia (m/z=17), Ser (m/z=87), N-methyl methoxinine (Nmm; m/z=145), Val (m/z=99), homoisoleucine (Hil; m/z=127), dehydroalanine (Dha; m/z=69), and Ile (m/z=113).
Subsequent fragmentation occurs after a rearrangement resulting in the loss of 166 mass units formed by proline and part of the lanthionine (Lan) residue. The Lan residue is eliminated in the form of dehydroalanine to give an m/z of 797.4. A. G. Craig, 20 Biological Mass. Spec. 195 (1991). The cleavage of the Lan bridge occurs with a transfer of a pair of electrons from the electron-rich sulfur atom to the α-proton of Lan 7. This results in breaking of the sulfur bridge between Lan and the formation of a Dha residue instead of Lan 7. This sulfur is retained by Lan 14 as a thiol yielding cysteine in subsequent cleavages.
The fragmentation continues with the subsequent loss of amino acids resulting in m/z of 650.2, 549.2, 422.2, and 351.3, corresponding to loss of Phe (m/z=147), Thr (m/z=101), Hil (m/z=127), and Ala (m/z=71). The next loss of 250 units is a coupled loss of phenylalanine and cysteine, leaving the terminal succinate fragment of 101 mass units. Throughout the spectrum the loss of 18 units (i.e. H 2 O) is observed.
EXAMPLE 10
Assignment of Hil
Two, 2-amino-4-methylhexanoic acid (homoisoleucine, Hil) units were identified after analyzing the PS (phase sensitive) DQF COSY and TOCSY spectra of vitilevuamide. The stereochemistry of the amino acids was confirmed by chemical synthesis of all four diastereomers, and evaluation of the 1-fluoro-2,4-dinitrophenyl-5-L-alanineamide (FDAA; Sigma Chemical Co., St. Louis, Mo.) derived amino acids by HPLC on a cyano column. The mixtures of (2RS,4S) and all four isomers of Hil were synthesized starting from S-(+) and (±)-1-bromo-2-methyl butane (Sigma Chemical Co. or Aldrich Chemical Co., Milwaukee, Wis.) respectively using the method of H. Han & R. A. Pascal, 55 J. Org. Chem. 5173 (1990). The diastereomeric mixture of (2RS,4S)-2-amino-4-methyl hexanoic acid was treated with catalase and L-amino acid oxidase (Aldrich Chemical Co.) at pH 8 for 12-18 hours. Upon acidification and reverse phase chromatography (9:1, MeOH/H 2 O), the pure (2R,4S) isomer of Hil was isolated. Using these standards it was possible to verify the stereochemistry of the two Hil residues in vitilevuamide by FDAA derivatization and cyano HPLC chromatography (MeOH/1% Acetic acid, 25:75-90:10 at 1 mL/min) with UV detection at 340 nm.
EXAMPLE 11
Assignment of N-methyl-methoxinine
The 1 H NMR signals of the unknown amino acid (C 6 H 11 O 3 N, 143 da) were assigned by using TOCSY and DQF COSY. COSY connectivity between 5.66 ppm (α proton), 4.66 ppm (β proton) and 3.59, 3.43 ppm (diastereotopic δ protons) established the basic structure. The presence of the N- and O-methyl group was confirmed by HMBC connectivity between the methyl singlets at 3.38 and 3.06 to the α and δ carbons respectively.
Nmm was synthesized through the intermediate 3-methoxy-2-hydroxypropionaldehyde (3-O-methylglyceraldehyde). This aldehyde was prepared by the procedure of J. R. Durrwachter et al., 108 J. Am. Chem. Soc. 7812 (1986), at a yield of 47%. NMR results were consistent with published data. This aldehyde was converted to 2-aminomethyl-3-hydroxy-4-methoxybutane nitrile by addition of methylamine in an alkaline medium followed by addition of potassium cyanide (80% yield). The structure of this nitrile was also confirmed by NMR. The nitrile was then subjected to acid hydrolysis, resulting in Nmm (58% yield). This procedure resulted in synthesis of all isomers. Proton and carbon-13 NMR data were obtained.
EXAMPLE 12
Stereochemistry of Amino Acids in Vitilevuamide
The stereochemistry of many amino acids can be determined by reverse phase HPLC after derivatization with FDAA (1-fluoro-2,4-dinitrophenyl-5-L-alanine-amide). P. Marfey, 49 Carlsberg Res. Commun. 591 (1984); J. G. Adamson et al., 202 Anal. Chem. 210 (1992).
Hydrolysis of vitilevuamide prepared according to the procedure of Example 1 or Example 2 was carried out in 5 mL of 6N HCl under a nitrogen atmosphere in a sealed bomb at 108° C. for 22 hours. After traces of HCl were removed by repeated evaporation in vacuo, the residual hydrolysate was suspended in 500 μl of water and derivatised with (1-fluoro-2,4-dinitrophen-5-yl)L-alanineamide (FDAA). HPLC analysis (Waters NOVAPAK C 18 ; 4.6×100 mm column, linear gradient elution, triethylammonium phosphate (50 mM, pH 3.0)/acetonitrile, 90:10-60:40 in 45 mins; 1.0 mL/min; UV detection at 340 nm) of FDAA-derivatized amino acid standards (Sigma Chemical Co.) coinjected with the vitilevuamide hydrolysate established the stereochemistry of the constituent amino acids with the exception of homoisoleucine, lanthionine, and N-methyl methoxinine.
The conditions for the stereochemistry determination of isoleucine included gradient cyano HPLC (Rainin Microsorb, 4.6×250 mm, at MeOH/1% acetic acid, 35:65-42:58 for 30 mins at 1 mL/min with UV detection at 340 nm. For homoisoleucine, similar conditions were used except that a linear gradient of 25% MeOH to 90% MeOH for 50 minutes at a flow rate of 1 mL/min was used.
These experiments established the presence of D-allo-threonine, D-valine, D-phenylalanine, D-alanine, L-serine, L-proline, L-isoleucine, D-allo-homoisoleucine, and L-homoisoleucine.
EXAMPLE 13
Toxicity Testing in Hunan Tumor Cell Lines
Vitilevuamide prepared according to the procedure of Example 1 or Example 2 was tested against a panel of human tumor cell lines: (a) a colon cancer cell line, HCT 116 (obtained from ATCC), M. Brattain, 41 Cancer Res. 1751 (1986); (b) an adenocarcinoma cell line, A549, D. J. Giard, 51 J. Nat'l Cancer Inst. 1417 (1973); (c) a malignant melanoma cell line, SK-MEL-5, H. F Oteggen, 41 J. Nat'l Cancer Inst. 827 (1968); and (d) a kidney carcinoma cell line, A498, S. Aaronson, 51 J. Nat'l Cancer Inst. 1417 (1973). Cells were cultured according to the procedure of M. C. Alley et al., 48 Cancer Res. 589 (1988), hereby incorporated by reference.
Screening was performed in a 96-well microtiter plate by the standard 3- 4,5-dimethylthiazol-2-yl!-2,5-phenyltetrazolium bromide; thiazolyl blue (MTT) cell inhibition assay adopted for anticancer drug screening at NIH. J. Carmichael et al., 47 Cancer Res. 936 (1987), hereby incorporated by reference. Positive controls were run simultaneously.
Vitilevuamide was strongly cytotoxic against all of the cell lines tested, exhibiting 50% inhibitory concentrations (IC 50 ) as follows: 10 ng/mL in HCT 116 cells (FIG. 3); 0.2 μg/mL in A549 cells (FIG. 4); 0.5 μg/mL in SK-MEL-5 cells (FIG. 5); and 5 μg/mL in A498 cells (FIG. 6). Thus, vitilevuamide is an antitumor agent according to this test viewed by those skilled in the art as reasonably predictive thereof.
EXAMPLE 14
Tubulin Inhibition Assay
C6 rat glioma cells (ATCC CCL107) were seeded into the wells of a microtiter plate and then incubated for 1 day. The cells were then treated with a range of vitilevuamide concentrations, normally 5 orders of magnitude, and incubated for 4 additional hours. The cells were then treated for 1 hour with 1 mM dibuteryl-cAMP (db-cAMP), which causes the C6 cells to assume a spherical morphology ("rounding") within 60 minutes due to polymerization of tubulin. Cells that are exposed to tubulin-active compounds, on the other hand, display a different morphological change--flattening and adherence to the substrate. All of the wells were then jet aspirated, and the wells were resupplied with fresh medium containing MTT. The glioma cells metabolize MTT to a dark formazan dye. P. R. Twentyman & M. Luscombe, 56 Br. J. Cancer 279 (1987); F. Denizot & R. Lang, 89 J. Immunol. Methods 271 (1986). Following 4 hours of incubation, absorbance was measured at 450 nm. Colchicine (25 μg/mL) was used as the positive control.
In this assay, vitilevuamide showed the same effect as colchicine at a concentration of 4 μg/mL. FIG. 7 shows the absorbance of wells treated with vitilevuamide expressed as a function of the absorbance of wells treated with 25 μg/mL of colchicine. These results show that the antitumor activity of vitilevuamide is likely due to interaction with the microtubule system.
EXAMPLE 15
Vitilevuamide was also screened for in vivo activity by injecting CDF1 mice intraperitoneally on day 0 with 1×10 6 P388 tumor cells. Five animals were randomly assigned to a group. On days 1, 5, and 9 after tumor implantation, these mice were treated intraperitoneally with either a placebo or the drug. Animals were checked twice daily, and the day of death of each mouse was recorded. A positive drug response is defined as a greater than 25% increase in the mean life span (% ILS) relative to the placebo control. The results of this experiment are shown in Table 2.
TABLE 2______________________________________Dose (mg/kg/dose) % ILS______________________________________0.13 -45 (toxic)0.06 -13 (toxic)0.03 700.012 200.006 8______________________________________
These results show that vitilevuamide exhibited a % ISL of 70 at a dose of 0.03 mg/kg. Thus, vitilevuamide is an antitumor agent according to this test viewed by those skilled in the art as reasonably predictive thereof.
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A purified bicyclic depsipeptide, vitilevuamide, from the ascidians Didemnum cuculliferum and Polysyncraton lithostrotum is disclosed. Vitilevuamide has antitumor activity as demonstrated by standard in vitro and in vivo assays. An anticancer composition is also disclosed, comprising an effective amount of vitilevuamide and an inert carrier. A method of treating cancer is also disclosed, comprising administering an anticancer composition comprising an effective amount of vitilevuamide and an inert carrier.
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BACKGROUND
[0001] This invention relates generally to forecasting and replenishment processes, and more particularly, the present invention relates to a method for managing collaborative forecasting and replenishment processes over a computer network.
[0002] Businesses are continuously striving to find new and better ways to improve their inventory management processes in order to reduce business risks. One of the reasons why current inventory management systems fail is due to ineffective demand forecasting methods and deficient supply replenishment processes utilized by supply management teams across many industries. Predicting future demand for goods and materials is fraught with uncertainties which are further fueled by dynamic economic conditions and fluctuating markets. This instability can make forecasting future supply needs especially difficult for the manufacturing industry. For example, if the manufacturer finds either an increased or reduced demand in the product compared to its forecast, strain is placed throughout the supply chain where overstocking or depletion of components can occur quickly. In addition, if the supplier cannot deliver the components, manufacturers will often not be able to react quickly to meet demand, seek alternative sources, etc. Without keeping large stock of components on hand at the manufacturer's site, supply problems occur readily. However, keeping large stock has additional problems of its own, such as higher storage costs, an increased loss probability because components become outdated, etc. Moreover, electronic parts tend to reduce in value with time (i.e., a part that the manufacturer purchases in January will cost less in March and much less in June and so on).
[0003] Various solutions have been developed to improve existing inventory management systems such as storage warehouses or replenishment centers for facilitating quick and easy access to goods creating a buffer in the event of a sudden change in demand. By adding a third player to the supply chain process, however, additional problems in inventory management are presented. For example, coordinating supply requirements and forecasts, changes to these requirements, and their corresponding delivery schedules can be cumbersome and prone to error. Multi-party communications between supplier, warehouse, and buyer must be consistently accurate and reliable otherwise a breakdown in the supply chain can occur creating a ‘chain effect’ of inventory delays, and/or inaccuracies.
[0004] Software systems have been developed to address inventory replenishment problems utilizing various techniques. Such software systems are generally targeted to satisfying specific needs within a supply chain subprocess and are not equipped to manage a complete end-to-end collaborative forecast and replenishment cycle.
[0005] As the manufacturing world begins to move to build-to-order environment, greater demands are expected from the manufacturer to lower total costs in the complete supply chain, shorten throughput times, reduce stock to a minimum and provide more reliable delivery dates without constraining production due to supply issues.
[0006] What is needed, therefore, is a way to integrate and manage collaborative forecasting and replenishment processes over a computer network.
BRIEF SUMMARY
[0007] An exemplary embodiment of the invention relates to a method and storage medium for integrating forecasting and replenishment activities for a networked supply chain including an enterprise and at least one supplier. The method comprises receiving a demand forecast for a first manufacturing cycle from the enterprise, performing a hub inventory assessment, performing a capability assessment, and transmitting a commitment response to the enterprise based upon the demand forecast, the results of the hub inventory assessment, and the results of the capability assessment. The demand forecast is utilized to manage hub inventory for use in a second manufacturing cycle. Other embodiments include a storage medium for implementing the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Referring now to the drawings wherein like elements are numbered alike in the several FIGURES:
[0009] [0009]FIG. 1 illustrates a computer network system upon which the integrated forecasting and replenishment tool is implemented in an exemplary embodiment;
[0010] [0010]FIG. 2 is a flowchart describing the implementation of the integrated forecasting and replenishment tool in an exemplary embodiment; and
[0011] [0011]FIG. 3 is a sample demand/replenishment chart illustrating the features of the integrated forecasting and replenishment tool in an exemplary embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0012] In an exemplary embodiment, the integrated forecasting and replenishment tool is implemented via a computer network system such as that depicted in FIG. 1. System 100 includes an enterprise site 102 which, for purposes of illustration, represents one of a plurality of electronics manufacturing facilities belonging to a business enterprise, although it will be understood that additional sites may be included in system 100 in order to realize the advantages of the invention. The business enterprise of FIG. 1 may be a large manufacturing company with manufacturing sites located all over the globe. Thus, enterprise site 102 represents one of the facilities operated by the business enterprise. Enterprise site 102 comprises divisions or groups which share requirements for common materials with similar divisions or groups from other sites associated with the business enterprise. Enterprise site 102 includes a client system 104 which represents a first manufacturing division (also referred to as group) within enterprise site 102 . The terms ‘group’ and ‘division’ are synonymous and signify a product, commodity, or specialty manufacturing group associated with a business enterprise which share some common tasks or business objectives. Client system 106 signifies a second group for enterprise site 102 . Client systems 104 and 106 request applications and data via a server 108 via what is commonly referred to in the art as a client/server architecture. It will be understood that any number of client systems and/or groups may be employed by enterprise site 102 . Server 108 executes the business enterprise's Material Requirements Planning (MRP) and/or Enterprise Resource Planning (ERP) applications, among other tools or applications suites desired. Applications such as web server software and groupware applications are executed by server 108 for facilitating communications within site 102 as well as between site 102 and external entities. Further server 108 is executing database management software for communicating with data storage device 110 . Data storage device 110 serves as a repository for a range of databases and data utilized by site 102 and which will be further explained herein. A communications link 113 is also included in site 102 which allows client systems 104 and 106 , data storage device 110 , and server 108 to communicate with another. Communications link 113 may be a high speed local area network such as an Ethernet, token ring, or OSI model network. In a system where more than one site 102 exist, a wide area network (WAN) linking sites together via routers, gateways, or similar software and/or hardware devices may be employed. A firewall 112 filters out unauthorized communication attempts by external entities and provides data integrity of system resources of site 102 .
[0013] Central server 120 is also included in system 100 and provides a centralized system and location for directing and coordinating the activities implemented by the integrated forecasting and replenishment tool as well as other system resources desired by the business enterprise. Server 120 may be a collection of high powered computers employing multiple processors, including scalable memory and high speed capabilities. Server 120 is preferably executing applications including a central MRP engine, an optimization tool, and the integrated forecasting and replenishment tool of the invention. Specifically, central server 120 receives projected forecast data from various groups of a business enterprise which may span several enterprise site locations. Server 120 aggregates and synthesizes the forecast data, and then generates a demand forecast in the nature of an unconstrained group level forecast that is transmitted back to associated suppliers for further action. Responses received by these suppliers are further exploited by server 120 resulting in the generation of a demand forecast in the nature of a constrained forecast which is transmitted to suppliers at the individual site level. Commitment responses received from suppliers are processed and a site specific build plan is generated and implemented. Modifications to build plans are effectuated when desirable via the integrated forecasting and replenishment tool and supply replenishment activities are carried out accordingly. These processes are further described herein in FIGS. 2 and 3.
[0014] Replenishment service center (RSC) 114 provides local storage of supplier goods and inventory under an agreement with site 102 . RSC 114 may be a warehouse or commercial storage facility. In one embodiment, RSC 114 includes client system 115 which is Internet-enabled and which operates web browser software for communicating with site 102 and suppliers 116 . RSC 114 receives requests for goods in the form of a pull signal from enterprise site 102 and/or suppliers 116 .
[0015] Suppliers 116 provide goods to enterprise sites for a business enterprise and may be geographically dispersed around the globe. Suppliers 116 include client systems 118 which are Internet-enabled and operate web browser software.
[0016] RSC 114 is strategically located in close proximity to site 102 in order to provide quick material deliveries as needed. RSC 114 may also be responsible for servicing additional sites of the business enterprise that are also located nearby in addition to site 102 if desired. Suppliers 116 provide goods to site 102 via RSC 114 based upon demand requirements of and/or agreements with site 102 . Suppliers 116 ensure adequate supply levels of goods at RSC 114 via network communications facilitated by the integrated forecasting and replenishment tool as will be described further herein.
[0017] In an exemplary embodiment, supplier collaboration is provided via a shared communications infrastructure; namely, a trade network environment. The integrated forecasting and replenishment tool is executed within a computer network system such as system 100 of FIG. 1. FIG. 2 describes the forecast collaboration and replenishment process utilizing the integrated forecasting and replenishment tool.
[0018] The integrated forecasting and replenishment tool combines the planning and execution processes into a single application with visibilities provided and available to enterprise sites, RSC providers, and suppliers of inventory necessary to insure the flow of the right material to each site in the needed quantities. It also provides visibility to materials in transit from a supplier site to the enterprise RSC, materials at each RSC, and materials in transit from each RSC to the respective enterprise site.
[0019] The implementation of the integrated forecasting and replenishment tool is described in FIG. 2. The process steps recited in FIG. 2 relate to a single manufacturing cycle that is defined by a length of time such as a work day, a work shift, a five-day work week, or other similar time measurement. Thus, the process described in FIG. 2 is repeated for each cycle as specified by the enterprise. A demand forecast in the nature of an unconstrained forecast is received by a supplier over the web at step 202 . The unconstrained forecast represents an aggregated demand or projected forecast received from a particular group which may be scattered among a plurality of enterprise site locations. In other words, if there are multiple physical sites for the business enterprise which employ a particular manufacturing group, then the unconstrained forecast is aggregated and provided to each supplier at the business enterprise group level to which each supplier will respond with a supply capability statement. For example, one group submits a demand for 1,000 widgets of which 400 were requested by a first enterprise site such as enterprise site 102 of FIG. 1. An unconstrained forecast includes the aggregated customer demand exploded into time-bucketed materials requirements, without taking into consideration any resource constraints. The unconstrained forecast is assembled via a central materials resource planning (MRP) engine and provided to suppliers over the web.
[0020] Utilizing information in the unconstrained forecast, the supplier performs an inventory hub assessment to determine current quantities of stored items provided in the unconstrained forecast at step 204 . This information may be found in data storage device 110 via the tool. The hub inventory refers to inventory materials stored in RSC 114 . The supplier also performs a capability assessment at step 206 which refers to a supplier's ability to provide the items in the unconstrained forecast taking into account the stored quantities of items in the hub inventory. Upon completion of these assessments, the supplier generates a supply capability statement which represents the greatest amount of inventory a supplier can make available to the buyer in order to satisfy the buyer's demand over a specified time period. This statement is initiated over the web and transmitted to the originating group at step 208 .
[0021] An optimization process and materials requirements analyses are performed on the supply capability statement at step 210 resulting in a demand forecast in the nature of a constrained forecast. This process involves examining the supplier capability in light of constraints in resources, equipment capacities, business plans, and similar obstacles or concerns generally encountered by a business in a manufacturing environment. The optimization and materials requirements analyses can be performed utilizing proprietary software or methods or may be accomplished via the method provided in U.S. application Ser. No. 09/910,544 entitled, “Network-Based Supply Chain Management Method”, which was filed on Jul. 20, 2001 by the same assignee as the present application, and which is incorporated herein by reference in its entirety. The process recited in the aforementioned application involves feeding supplier capability statements into a centralized constraint-based optimization tool to square sets and add capacity constraints. Based on the results of this squared set analysis, a squared set build plan is built and delivered to an MRP engine to generate requirements for a squared set constrained forecast.
[0022] A constrained forecast is provided via the tool over the web and received by the respective supplier at step 212 . The supplier responds with a formal commitment also at the site level at step 214 . This formal commitment from the suppliers reflects what they will build to, or the nature and quantity of items/goods that they will deliver, and preferably includes a minimum supply that will be maintained over a specified time period.
[0023] During the manufacturing process, as site 102 consumes materials, replenishment execution is performed at step 216 . This involves periodic pull signals being transmitted to the RSC as needed, requesting parts be delivered to the enterprise site from the RSC.
[0024] Since the supplier has visibility of RSC inventory statuses and pull signal information, the supplier can readily determine when to restock the RSC in order to meet the time-bucketed demand commitments as well as the guaranteed minimum supply levels. FIG. 3 illustrates a sample demand schedule and replenishment scenario for two time cycles.
[0025] Each cycle of FIG. 3 is further broken down into time buckets reflected as “time 1 ” through “time n”. In the first cycle, a demand for part “xyz” reveals a desired quantity of 100 for each time period in the cycle. A supplier has committed to maintaining a minimum supply of the demand quantity over two time periods, i.e., 200 as shown at “time 1 ”. Upon performing the capability assessment described in step 206 , the supplier responds with a formal commitment of 100 parts for each time period of the cycle. Thus, for cycle 1 at “time 1 ”, there is a surplus of 200 parts, i.e., the hub inventory of 200 plus the commitment of 100 parts at “time 1 ” minus the expected consumption of 100 parts at “time 1 ”.
[0026] The same analysis applies for “time 2 ” through “time n” of cycle 1 .
[0027] At cycle 2 , the demand has been reduced to 10 parts for each time period “time 1 ” through “time n”. At “time 1 ” there is 200 parts in inventory as a result of an inventory assessment performed in step 204 of FIG. 2. The supplier performs a capability assessment as described in step 206 of FIG. 2 and returns a response of “0” parts because the current hub inventory can more than meet the required demand for the time periods shown in cycle 2 . The hub inventory does not require replenishment and the two-time period minimum supply is maintained.
[0028] By combining the replenishment information into the planning processes and assessing the hub inventory levels as a source of supply, the amount of excess materials forced into the supply chain can be minimized. Combining supply assessments or forecast/commit processes with enhanced replenishment processes and invoicing processes into an integrated application with expanded visibility capabilities offers benefits to supply chain partners in the way of common visibility of demand and supply re-balancing, capacity optimization, inventory reduction, premium transportation expense reduction, and minimization of inventory stock outs.
[0029] As described above, the present invention can be embodied in the form of computer-implemented processes and apparatuses for practicing those processes. The present invention can also be embodied in the form of computer program code containing instructions embodied in tangible media, such as floppy diskettes, CD-ROMs, hard drives, or any other computer-readable storage medium, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention. The present invention can also be embodied in the form of computer program code, for example, whether stored in a storage medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via electromagnetic radiation, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention. When implemented on a general-purpose microprocessor, the computer program code segments configure the microprocessor to create specific logic circuits.
[0030] While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.
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An exemplary embodiment of the invention relates to a method and storage medium for integrating forecasting and replenishment activities for a networked supply chain including an enterprise and at least one supplier. The method comprises receiving a demand forecast for a first manufacturing cycle from the enterprise, performing a hub inventory assessment, performing a capability assessment, and transmitting a commitment response to the enterprise based upon the demand forecast, the results of the hub inventory assessment, and the results of the capability assessment. The demand forecast is utilized to manage hub inventory for use in a second manufacturing cycle. Other embodiments include a storage medium for implementing the invention.
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TECHNICAL FIELD
This invention relates to the manufacture of seamless tubes of polymers, such as polyimides.
BACKGROUND OF THE INVENTION
The fabrication of a seamless polyimide tube has been discussed in patent literature in recent years. U.S. Pat. No. 5,433,913 to Kawauchi et al. serves as an example. It employs a ring coating process coupled with ultrahigh viscosity coating solutions.
High performance polyimides are very difficult to process. They are thermosetting resins, which cannot be reformed with heat. Furthermore, they are soluble in a limited number of relatively high-boiling solvents, such as n-methyl-2-pyrrolidone (NMP) and dimethyl acetamine] (DMAc). Curing conditions for polyimides are difficult to optimize and have a profound effect on the mechanical properties of the cured film. Additionally, the high temperatures required for polyimide curing limit the choice of coating substrates to metal and ceramics. Finally, the cost of polyamic acid resins is high, giving great advantage to a process which can minimize resin waste.
This invention is a process by which a seamless polyimide tube can be cast from a high viscosity polyamic acid resin. The process is simple, effective, relatively fast, and highly efficient in that minimal waste material is generated.
DISCLOSURE OF THE INVENTION
In accordance with this invention, the amount of resin to constitute the final tube is computed and an amount of solution having that amount precursor for that amount of resin is defined. That amount of solution is applied generally evenly over a mandrel. The solution may be forced from a nozzle or simply poured. The mandrel is rotated while a doctor blade, canted to keep material form of the doctor blade, is moved along the length of the mandrel at a amount of separation from the mandrel consistent with the predetermined thickness which the final tube is to have. After the doctoring step, the solvent is extracted with heat. The film is further cured to form the polyimide resin and then removed from the mandrel.
BRIEF DESCRIPTION OF THE DRAWINGS
The details of this invention will be described in connection with the accompanying drawings, in which
FIG. 1 is a top view and
FIG. 2 is a side view of the doctoring action in mid-process.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The precursor used in this invention is a polyamic acid solution comprised of the copolymer of biphenyl tetracarboxylic dianhydride (BPDA) and p-phenylenediamine (pPDA). The solvent preferably is DMAc, although NMP is useful alternatively, and any comparable solvent is consistent with this invention. The solution may be 15 weight percent (i.e., 15 grams of monomer per 100 grams of total solution weight). Boron nitride can optionally be compounded with the resins to increase thermal conductivity.
The viscosity of the polyamic resins preferably may be between 10,000 cP and 100,000 cP, with particular preference at 50,000 cP. Optionally, numerous combinations of dianhydrides and diamines can be used. The most preferred combination of monomer and solvents are specified in the foregoing have been selected for the high mechanical and thermal properties obtained. The key solution parameters, from a processing standpoint, are obtaining a high viscosity in the coating solution and maintaining control of the percent solids of the solution. Below 10,000 cP, the solution does not have the mechanical stability to maintain a shape at room temperature, leading to poor thickness uniformity. Above 100,000 cP, the solution is so thick that air bubbles cannot be easily removed from the solution, giving rise to coating defects.
Once the foregoing solution of polyamic acid resin is synthesized, it is degassed under a vacuum for a period of time until no escaping bubbles are seen. The solution can then be drawn into a syringe, which has a large orifice. By knowing what dimensions are desired for the polyimide tube, the amount of solution required is readily determined. For example, if the tube of 50 microns thickness, 25.4 mm inner diameter, and 250 mm length is to be manufactured, the volume of material needed is 0.005 cm×2.54 cm×25.0 cm, which equals 0.997 cubic cm. Given a polyimide density of 2.5 gr/cubic cm, 2.49 gr of polyimide will be in the final tube. An amount of solution containing that amount of polyimide is used in accordance with this invention. Since the starting solution percent solids is 15%, 16.6 gr of solution will be used. Thus, this amount of resin is transferred to the syringe. Since the edges of the tube typically require trimming, a small excess of material may be employed, limited to an amount of solids that will be trimmed.
Coating is on a cylindrical mandrel 1 . The mandrel is an aluminum cylinder of 25.2 mm outer diameter The surface is highly polished to a near mirror surface. The surface is treated with a thin coating of silicon dioxide (not separately illustrated), which can be applied by a sputter coating process. Typical coating thicknesses of the silicon dioxide range from 0.5 to 2 microns. It is important to note that the mandrel must be straight and concentric about its centers. Any deviation from straightness and roundness leads to thickness variation in the final part. A tolerance of 1 mil on the concentricity appears to be sufficient for achieving thickness uniformity. The mandrel is mounted on a lathe (not shown) or similar equipment capable of rotating the mandrel as shown by arrow 2 . While rotation is typically horizontal, no reason appears why the process of this invention would not function in a vertical direction of rotation.
The mandrel 1 is rotated at a suitable rate, such as 60 rpm or 181 rpm. At this point, the syringe (not shown) is brought into close proximity to the mandrel. While the mandrel 1 is rotating, the amic acid resin solution is dispensed onto the mandrel surface in a consistent manner so as to spread the material as evenly as possible across the mandrel surface. In a mass production setting this can readily be done at a fixed rate by equipment which operates the singe while traversing the part at a speed which corresponds to the amount of solution being dispensed. This step is to cover the surface of the mandrel with a generally disposed solution in correct quantity to make a polyimide tube of the correct thickness. equipment which operates the syringe while traversing the part at a speed which corresponds to the amount of solution being dispensed. This step is to cover the surface of the mandrel with a generally dispersed solution in correct quantity to make a polyimide tube of the correct thickness.
The syringe is then moved away and the mandrel 1 is maintained at the rotational rate. A blade 3 is then brought to a specified distance from the mandrel. A blade 3 of 1 mm thickness with flat or sharp edge functions well it is believed that a blade 3 can have a wide range of configurations and function well. The shape, material, and orientation of the blade are vital to the process. A steel blade coated with a thin layer of TEFLON fluoropolymer is preferred. The blade is positioned normal to the axis of rotation of the mandrel FIG. 1 is a top view and FIG. 2 is a side view of system during the process.
A blade 3 is moved along the mandrel parallel to the axis of the mandrel in the direction of arrow 5 , which doctors the resin solution on a mandrel surface 7 to a uniform thickness illustrated by spaced arrows 9 a and 9 b. The rate of translation in the direction of arrow 5 can be varied. Rates of 10 cm/min and faster are known to give tubes of uniform thickness.
The doctor coating 11 is on the left of a blade 3 in FIG. 1 and FIG. 2 . The incline of a blade 3 is essential to its function. If the blade is simply perpendicular from the direction of arrow 5 (the direction of travel), material is pushed along the mandrel surface until excess buildup creeps over the side of the blade and causes defects on the trailing side of the blade. With the incline, excess material buildup is not in the shape of a taurus, but rather a cone 13 . As this buildup grows, it is knocked back onto the side of the leading edge of the blade Thus, no excess is transferred to the trailing edge and no defects are generated.
The distance between the blade and the mandrel surface is found preliminarily from the desired thickness of the polyimide tube, the percent solids of the of the coating resin as described in the foregoing. Typically, however, the distance must be increased over this estimate because the precursor solution does not shear sharply as a solid material would. Rather, due to it surface tension and viscosity, the precusor solution parts film the blade with a small radius or meniscus. Thus, the coating thickness is typically less than the distance between the mandrel and blade. The increased distance to compensate for this is best determined empirically. Once the proper overall distance of the doctor blade to the mandrel is established, polyimide tube thicknesses are highly reproducible so long as blade distance and coating solution viscosity and percent solids are kept constant. For a coating solution as described in the foregoing with 15% solids and 50,000 cP, a blade distance of 33 mils consistently provides a final polyimide tube of 45 microns in thickness.
After applying and doctoring the polyamic acid resin onto the mandrel, the coated mandrel is removed from the lathe. It is then transferred to an oven for evaporation of the solvent. This may be for 1 hour at 125 degrees C. Upon evaporation of the solvent, the mandrel is transferred to an oven set to 200 degrees C. The mandrel and coating are held at this temperature for 2 hours. The temperature is then increased to 250 degrees C. and held for 2 additional hours. Finally, the oven temperature is increased to 380 degrees C. and held for one hour. This baking process has been shown to effectively eliminate solvents and to polymerize the polyamic acid to give a polyimide tube of sound mechanical properties. However, the curing schedule must be optimized empirically for any coating thickness, viscosity, percent solids, solvent, and monomer combination used, as this process is highly dependent on solvent level and type, temperature, and similar factors.
Upon final cure of the polyimide film, the mandrel is removed from the oven and allowed to equilibrate to room temperature. If the film has been cast at a uniform thickness and if the silicon dioxide coating is also uniform, no preferential adhesion to the mandrel should occur and the tube should be round and free of wrinkles. Because of the difference in thermal expansion between the aluminum core of the mandrel and the polyimide film, there should be a small gap between the mandrel outer surface and polyimide inner surface. Therefore, removal of the film is a trivial matter of simply sliding the part off the mandrel.
The advantages of this process over existing processes include high speed—a part can be coated in 2 minutes or less. In fact, it is feasible that multiple parts could be coated on the same equipment, giving very high yield. Additionally the desired coating thickness can be achieved in one coating pass, eliminating additional drying steps that would be required for multiple pass/dip methods. Furthermore, the process can provide tubes of high thickness uniformity. Samples have been made at +/−5 microns, using a mandrel that is rated for concentricity of 5 mils. A mandrel of 1 mil concentricity or better should bring the thickness uniformity to within +/−2 microns. And finally, very little waste material is generated. By dispensing a fixed and controlled amount of resin on to the mandrel surface, less than 1 ml of waste per part has been generated. This can be contrasted to a vertical dip or ring coating process in which a large amount of coating resin must be generated to coat mandrels. The potential yield for coating resin with this process is significantly greater. Thus, by increasing throughput and minimizing material waste while maintaining polyimide tube quality, a significant cost saving can be expected for this process over existing processes.
It will be clear that many of the materials used as described above may be replaced by comparable materials so long as the coating of a mandrel with a solution containing the amount of resin for final thickness is achieved. Accordingly, patent coverage should be as provided by law, with particular reference to the accompanying claims.
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To make a seamless tube of polyimide, an amount of polyamic acid precursor to constitute the final tube is applied eveny as a solution to a cylindrical mandrel. The mandrel is rotated while a canted doctor blade smoothes the solution. The solvent is then expelled and the remaining precursor cured by heat.
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FIELD OF THE INVENTION
[0001] The invention relates to nitrate derivatives of cilostazol useful in the treatment of vascular and metabolic diseases.
BACKGROUND OF THE INVENTION
[0002] Vascular and metabolic diseases are, despite cancer, the leading causes of death in the western world. Although many different ways of treating vascular and metabolic diseases are known, there is still a need for improved medication. Life-style modifications and drug therapy can decrease and delay the morbidity and mortality associated with these diseases. Treatments which have been proven to reduce the risk for morbidity and mortality in vascular diseases have been typically shown to either improve impaired vascular function or to delay/prevent the progression of vascular dysfunction caused by hypertension, atherosclerosis or other classical metabolic risk factors. Examples for such treatments are calcium channel blockers, beta blockers, angiotension-enzyme converting inhibitors or angiotension receptor blockers.
[0003] In patients with atherosclerosis, who are suffering e.g. from angina pectoris, one of the established standard treatments involves treatment with organic nitrates, specifically nitrate esters, such as glyceryl trinitrate (nitroglycerine), isosorbide dinitrate, or penta-erythrityl tetranitrate, which act all as coronary vasodilators and improve symptoms and exercise tolerance. Most organic nitrates (e.g. mononitrates and trinitrates) are fast acting pharmaceuticals with a relatively short halflife and have the typical disadvantage that patients develop a nitrate tolerance, meaning that part of the pharmacodynamic effect is lost during chronic treatment and a three times daily dosing regimen.
[0004] In the case of peripheral arterial disease (PAD) which is typically caused by hypertension and atherosclerosis and presents clinically with intermittent claudication, compounds with vasodilating properties have been shown to improve symptoms and walking. Two established licensed compounds for treatment of PAD patients are cilostazol (a phospho-diesterase III inhibitor) and pentoxifylline. Cilostazol (U.S. Pat. No. 4,277,479) acts as a direct arterial vasodilator. In addition to its reported vasodilator and antiplatelet effects, cilostazol has been proposed to have beneficial effects on plasma lipoproteins, increasing plasma high density lipoprotein cholesterol and apolipoproteins.
[0005] Nitrate esters of drugs in general are described in WO 00/61357. Diazeniumdiolate derivatives have recently been recognized as alternatives for nitrates, setting free two molecules of NO under physiological conditions. A diazeniumdiolate derivative of tacrine is described by L. Fang et al., J. Med. Chem. 51, 7666-7669 (2008).
SUMMARY OF THE INVENTION
[0006] The invention relates to compounds of formula
[0000]
[0000] or the corresponding oxy-imine derivative
[0000]
[0000] wherein A is
—(C═O) a —(CH 2 ) b —O—NO 2 ;
—(C═O)—(CH 2 OCH 2 ) c CH 2 —O—NO 2 ;
—(CH 2 CH 2 O) c CH 2 CH 2 —O—NO 2 ;
[0007] —(C═O) a —(CH 2 ) d —CH[(CH 2 ) e —O—NO 2 ] 2 ;
—(C═O)—NR 1 —(CH 2 ) b —O—NO 2 ;
—(C═O)—O—(CH 2 ) b —O—NO 2 ;
—CH 2 O—(C═O)—NR 1 —(CH 2 ) b —O—NO 2 ; or
—CH 2 O—(C═O)—O—(CH 2 ) b —O—NO 2 ;
—CH 2 O—(C═O)—(CH 2 ) b —O—NO 2 ;
a is 0 or 1; b is between 1 and 10; c is 1, 2 or 3; d is 0, 1 or 2; e is between 1 and 4; R 1 is H, C 1-4 -alkyl or —CH 2 O—(C═O)—NH—(CH 2 ) b —O—NO 2 ; and such compounds wherein —O—NO 2 is replaced by
[0000]
[0000] wherein R 2 and R 3 are both ethyl or 2-aminoethyl, or NR 2 R 3 together represent pyrrolidine, piperidine, piperazine or 4-methylpiperazine.
[0014] Furthermore the invention relates to pharmaceutical compositions comprising the compounds as defined hereinbefore, to the compounds as defined hereinbefore for the treatment of vascular and metabolic diseases, and to a method of treatment of vascular and metabolic diseases using the compounds and pharmaceutical compositions as defined hereinbefore.
[0015] The compounds of the invention represent useful medicaments for the treatment of vascular and metabolic diseases, for example, atherosclerosis, in particular connected with hypertension, also ocular and pulmonary hypertension, heart failure, in particular chronic heart failure after a heart attack (myocardial infarction), stroke, angina pectoris, cerebrovascular disease, coronary artery disease, left ventricular dysfunction and hypertrophy, and peripheral arterial disease (PAD), in particular intermittent claudication. The compounds of the invention have superior vasodilating properties compared to cilostazol (formula 1, A=hydrogen).
DETAILED DESCRIPTION OF THE INVENTION
[0016] The compound of formula 1, wherein A is hydrogen, is known under the name cilostazol. The compound of formula 1A, wherein A is hydrogen, is a tautomeric form of cilostazol, wherein the amide function is present as an oxy-imine function (keto-enol tautomerisim). When, in a compound of formula 1A, A is different from hydrogen, the oxy-imine function cannot revert to the amide function and form a tautomeric equilibrium. Such a compound of formula 1A represents a stable regio-isomer of the corresponding compound of formula 1.
[0017] C 1-4 -alkyl is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, or tert-butyl, preferably methyl, ethyl or n-propyl, in particular methyl.
[0018] The compounds of formula 1 and 1A, wherein A has the indicated meanings, are useful in the treatment of vascular and metabolic diseases.
[0019] Vascular diseases considered are, for example, hypertension and atherosclerosis and typical related consecutive diseases and their corresponding complications, in particular, ocular and pulmonary hypertension, chronic heart failure, heart failure after a heart attack (myocardial infarction), cerebral ischaemia in general and, specifically, transient ischaemic attacks (TIAs), prolonged neurological deficits (PRIND), stroke (ischaemic and non-ischaemic), chronic cerebrovascular diseases, stable and unstable angina pectoris, coronary artery disease, cardiac dysfunction, specifically left or right ventricular dysfunction and hypertrophy, peripheral arterial disease (PAD) at all stages, specifically including abnormalities in micro- and macrovascular function such as neuropathy, endothelial dysfunction, cold feet, impaired wound healing, ischaemic ulcers and necrosis, critical limb ischaemia, intermittent claudication, chronic or intermittent pain syndromes related to peripheral artery disease, polyneuropathy, and chronic and acute inflammatory vascular diseases. Furthermore, treatment and prophylaxis is considered of complications after peripheral vascular interventions such as balloon angioplasty and/or stenting, portal hypertension, chronic inflammatory vascular diseases, mixed connective tissue diseases with vascular complications, treatment of vascular complications in patients with Morbus Raynaud or Morbus Osler, treatment of typical micro- and macro-vascular complications of diabetes mellitus, abnormalities of platelet function such as increased platelet adhesion and resulting hypercoagulability, and conditions typically accompanying vascular diseases as described above.
[0020] Metabolic diseases considered are, for example, diabetes mellitus type 1 and 2, impaired glucose tolerance, all dyslipidaemias such hypercholesterolaemia, hypertriglyceridaemia, abnormalities of high density lipoproteins alone or in combinations with other dyslipidaemias, abnormalities of Apolipoprotein A1 or other subfractions of lipoproteins, and other metabolic diseases resulting in vascular complications and/or impaired platelet function.
[0021] Compounds of formula 1 and 1A can be manufactured by methods well known in the art. Preferably, cilostazol, i.e. the compound of formula 1, wherein A is hydrogen, is treated with an acylating compound or an alkylating compound, respectively, further carrying one or two bromine, chlorine or iodine atoms, according to standard procedures well known in the art. In the last step of the preferred synthesis, the bromine, chlorine or iodine is replaced by a nitrate ester or a diazeniumdiolate function by reaction with silver nitrate, or with a diazeniumdiolate in the presence of strong base in a dipolar aprotic solvent, respectively. In an alternative synthesis, the acylating or alkylating compound carries one or two hydroxy functions or protected hydroxy functions. These hydroxy groups are then transformed to a nitrate ester with nitric acid. A third synthesis procedure involves alkylation or acylation with the corresponding preformed reactive nitroxyalkyl or nitroxyacyl derivative, e.g. the 4-nitroxybutanoic acid pentafluorophenol ester. Introduction of a —CH 2 O—(C═O)—NR 1 —(CH 2 ) b —O—NO 2 group can be performed directly with the corresponding highly reactive chloride, which at the same time produces the compound wherein A is —CH 2 O—(C═O)—NR 1 —(CH 2 ) b —O—NO 2 and R 1 is a further —CH 2 O—(C═O)—NH—(CH 2 ) b —O—NO 2 group in the case that R 1 in the reactive chloride is hydrogen. Corresponding compounds with a —CH 2 O—(C═O)—O—(CH 2 ) b —O—NO 2 or —CH 2 O—(C═O)—(CH 2 ) b —O—NO 2 function are prepared analogously.
[0022] Preferred are compounds of formula 1, wherein
[0000] A is —(C═O) a —(CH 2 ) b —O—NO 2 ; —(C═O)—(CH 2 OCH 2 ) c CH 2 —O—NO 2 ;
—(CH 2 CH 2 O) b CH 2 CH 2 —O—NO 2 ; or —(C═O) a —(CH 2 ) d —CH[(CH 2 ) e —O—NO 2 ] 2 ; and
a, b, c, d and e have the indicated meanings.
[0023] More preferred are compounds of formula 1, wherein
[0000] A is —(C═O) a —(CH 2 ) b —O—NO 2 or —(C═O) a —(CH 2 ) d —CH[(CH 2 ) e —O—NO 2 ] 2 ; and
a is 0 or 1; b is between 1 and 6; d is 0, 1 or 2; and e is 1 or 2.
[0024] Even more preferred are compounds of formula 1, wherein
[0000] A is —(C═O) a —(CH 2 ) b —O—NO 2 or —(C═O) a —(CH 2 ) d —CH[(CH 2 ) e —O—NO 2 ] 2 ; and
a is 1; b is 2, 3, 4 or 5; d is 0 or 1; and e is 1 or 2.
[0025] Even more preferred are compounds of formula 1, wherein
[0000] A is —(C═O) a —(CH 2 ) a —CH[(CH 2 ) e —O—NO 2 ] 2 ; and a is 1; d is 0 or 1; and e is 1 or 2.
[0026] Further preferred are compounds of formula 1 or 1A, wherein
[0000] A is —(C═O) a —(CH 2 ) b —O—NO 2 ; —(C═O) a —(CH 2 ) d —CH[(CH 2 ) e —O—NO 2 ] 2 ;
—(C═O)—NR 1 —(CH 2 ) b —O—NO 2 ; —(C═O)—O—(CH 2 ) b —O—NO 2 ;
—CH 2 O—(C═O)—NR 1 —(CH 2 ) b —O—NO 2 ; —CH 2 O—(C═O)—O—(CH 2 ) b —O—NO 2 ; or
—CH 2 O—(C═O)—(CH 2 ) b —O—NO 2 ;
a is 0 or 1; b is between 1 and 10; d is 0, 1 or 2; e is between 1 and 4;
R 1 is H, C 1-4 -alkyl or —CH 2 O—(C═O)—NH—(CH 2 ) b —O—NO 2 ; and
such compounds wherein —O—NO 2 is replaced by
[0000]
[0000] wherein R 2 and R 3 are both ethyl or 2-aminoethyl, or NR 2 R 3 together represent pyrrolidine, piperidine, piperazine or 4-methylpiperazine.
[0027] Further preferred are compounds of formula 1 or 1A, wherein
[0000] A is —(C═O) a —(CH 2 ) b —O—NO 2 ; —(C═O) a —(CH 2 ) d —CH[(CH 2 ) e —O—NO 2 ] 2 ;
—(C═O)—NR 1 —(CH 2 ) b —O—NO 2 ; —(C═O)—O—(CH 2 ) b —O—NO 2 ;
—CH 2 O—(C═O)—NR 1 —(CH 2 ) b —O—NO 2 ; —CH 2 O—(C═O)—O—(CH 2 ) b —O—NO 2 ; or
—CH 2 O—(C═O)—(CH 2 ) b —O—NO 2 ;
a is 0 or 1; b is between 1 and 6; d is 0, 1 or 2; e is 1 or 2;
R 1 is H, methyl or —CH 2 O—(C═O)—NH—(CH 2 ) b —O—NO 2 ; and
such compounds wherein —O—NO 2 is replaced by
[0000]
[0000] wherein R 2 and R 3 are both ethyl, or NR 2 R 3 together represent pyrrolidine.
[0028] Even further preferred are compounds of formula 1, wherein
[0000] A is —(C═O) a —(CH 2 ) b —O—NO 2 ; —(C═O) a —(CH 2 ) a —CH[(CH 2 ) e —O—NO 2 ] 2 ; or —CH 2 O—(C═O)—NR 1 —(CH 2 ) b —O—NO 2 ;
a is 1; b is 2, 3, 4 or 5; d is 0 or 1; and e is 1 or 2;
R 1 is H or —CH 2 O—(C═O)—NH—(CH 2 ) b —O—NO 2 ; and
such compounds wherein —O—NO 2 is replaced by
[0000]
[0000] wherein NR 2 R 3 together represent pyrrolidine.
[0029] Most preferred are the compounds of the Examples.
[0030] The present invention relates also to pharmaceutical compositions that comprise a compound of formula 1 or 1A as active ingredient and that can be used especially in the treatment of the diseases mentioned above. Compositions for enteral administration, such as nasal, buccal, rectal or, especially, oral administration, and for parenteral administration, such as intravenous, intramuscular or subcutaneous administration, to warm-blooded animals, especially humans, are especially preferred. The compositions comprise the active ingredient alone or, preferably, together with a pharmaceutically acceptable carrier. The dosage of the active ingredient depends upon the disease to be treated and upon the species, its age, weight, and individual condition, the individual pharmacokinetic data, and the mode of administration.
[0031] The present invention relates especially to pharmaceutical compositions that comprise a compound of formula 1 or 1A, and at least one pharmaceutically acceptable carrier.
[0032] The invention relates also to pharmaceutical compositions for use in a method for the prophylactic or especially therapeutic management of the human or animal body, in particular in a method of treating a vascular and metabolic disease, especially those mentioned above.
[0033] The invention relates also to processes and to the use of compounds of formula 1 or 1A for the preparation of pharmaceutical preparations which comprise compounds of formula 1 or 1A as active component (active ingredient).
[0034] A pharmaceutical composition for the prophylactic or especially therapeutic management of a vascular and metabolic disease, of a warm-blooded animal, especially a human, comprising a novel compound of formula 1 or 1A as active ingredient in a quantity that is prophylactically or especially therapeutically active against the said diseases, is likewise preferred.
[0035] The pharmaceutical compositions comprise from approximately 1% to approximately 95% active ingredient, single-dose administration forms comprising in the preferred embodiment from approximately 20% to approximately 90% active ingredient and forms that are not of single-dose type comprising in the preferred embodiment from approximately 5% to approximately 20% active ingredient. Unit dose forms are, for example, coated and uncoated tablets, ampoules, vials, suppositories, or capsules. Further dosage forms are, for example, ointments, creams, pastes, foams, tinctures, lipsticks, drops, sprays, dispersions, etc. Examples are capsules containing from about 0.001 g to about 1.0 g active ingredient.
[0036] The pharmaceutical compositions of the present invention are prepared in a manner known per se, for example by means of conventional mixing, granulating, coating, dissolving or lyophilizing processes.
[0037] Preference is given to the use of solutions of the active ingredient, and also suspensions or dispersions, especially isotonic aqueous solutions, dispersions or suspensions which, for example in the case of lyophilized compositions comprising the active ingredient alone or together with a carrier, for example mannitol, can be made up before use. The pharmaceutical compositions may be sterilized and/or may comprise excipients, for example preservatives, stabilizers, wetting agents and/or emulsifiers, solubilizers, salts for regulating osmotic pressure and/or buffers and are prepared in a manner known per se, for example by means of conventional dissolving and lyophilizing processes. The said solutions or suspensions may comprise viscosity-increasing agents, typically sodium carboxymethylcellulose, carboxymethylcellulose, dextran, polyvinylpyrrolidone, or gelatins, or also solubilizers, e.g. Tween 80® (polyoxyethylene(20)sorbitan mono-oleate).
[0038] Suspensions in oil comprise as the oil component the vegetable, synthetic, or semi-synthetic oils customary for injection purposes. In respect of such, special mention may be made of liquid fatty acid esters that contain as the acid component a long-chained fatty acid having from 8 to 22, especially from 12 to 22, carbon atoms. The alcohol component of these fatty acid esters has a maximum of 6 carbon atoms and is a monovalent or polyvalent, for example a mono-, di- or trivalent, alcohol, especially glycol and glycerol. As mixtures of fatty acid esters, vegetable oils such as cottonseed oil, almond oil, olive oil, castor oil, sesame oil, soybean oil and groundnut oil are especially useful.
[0039] The manufacture of injectable preparations is usually carried out under sterile conditions, as is the filling, for example, into ampoules or vials, and the sealing of the containers.
[0040] Suitable carriers are especially fillers, such as sugars, for example lactose, saccharose, mannitol or sorbitol, cellulose preparations, and/or calcium phosphates, for example tricalcium phosphate or calcium hydrogen phosphate, and also binders, such as starches, for example corn, wheat, rice or potato starch, methylcellulose, hydroxypropyl methyl-cellulose, sodium carboxymethylcellulose, and/or polyvinylpyrrolidone, and/or, if desired, disintegrators, such as the above-mentioned starches, also carboxymethyl starch, crosslinked polyvinylpyrrolidone, alginic acid or a salt thereof, such as sodium alginate. Additional excipients are especially flow conditioners and lubricants, for example silicic acid, talc, stearic acid or salts thereof, such as magnesium or calcium stearate, and/or polyethylene glycol, or derivatives thereof.
[0041] Tablet cores can be provided with suitable, optionally enteric, coatings through the use of, inter alia, concentrated sugar solutions which may comprise gum arabic, talc, polyvinyl-pyrrolidone, polyethylene glycol and/or titanium dioxide, or coating solutions in suitable organic solvents or solvent mixtures, or, for the preparation of enteric coatings, solutions of suitable cellulose preparations, such as acetylcellulose phthalate or hydroxypropyl-methylcellulose phthalate. Dyes or pigments may be added to the tablets or tablet coatings, for example for identification purposes or to indicate different doses of active ingredient.
[0042] Pharmaceutical compositions for oral administration also include hard capsules consisting of gelatin, and also soft, sealed capsules consisting of gelatin and a plasticizer, such as glycerol or sorbitol. The hard capsules may contain the active ingredient in the form of granules, for example in admixture with fillers, such as corn starch, binders, and/or glidants, such as talc or magnesium stearate, and optionally stabilizers. In soft capsules, the active ingredient is preferably dissolved or suspended in suitable liquid excipients, such as fatty oils, paraffin oil or liquid polyethylene glycols or fatty acid esters of ethylene or propylene glycol, to which stabilizers and detergents, for example of the polyoxy-ethylene sorbitan fatty acid ester type, may also be added.
[0043] Pharmaceutical compositions suitable for rectal administration are, for example, suppositories that consist of a combination of the active ingredient and a suppository base. Suitable suppository bases are, for example, natural or synthetic triglycerides, paraffin hydrocarbons, polyethylene glycols or higher alkanols.
[0044] For parenteral administration, aqueous solutions of an active ingredient in water-soluble form, for example of a water-soluble salt, or aqueous injection suspensions that contain viscosity-increasing substances, for example sodium carboxymethylcellulose, sorbitol and/or dextran, and, if desired, stabilizers, are especially suitable. The active ingredient, optionally together with excipients, can also be in the form of a lyophilizate and can be made into a solution before parenteral administration by the addition of suitable solvents.
[0045] Solutions such as are used, for example, for parenteral administration can also be employed as infusion solutions.
[0046] Preferred preservatives are, for example, antioxidants, such as ascorbic acid, or microbicides, such as sorbic acid or benzoic acid.
[0047] The present invention relates furthermore to a method for the treatment of a vascular and metabolic disease, which comprises administering a compound of formula 1 or 1A, wherein the radicals and symbols have the meanings as defined above for formula 1 and 1A, in a quantity effective against said disease, to a warm-blooded animal requiring such treatment. The compounds of formula 1 or 1A can be administered as such or especially in the form of pharmaceutical compositions, prophylactically or therapeutically, preferably in an amount effective against the said diseases, to a warm-blooded animal, for example a human, requiring such treatment. In the case of an individual having a bodyweight of about 70 kg the daily dose administered is from approximately 0.001 g to approximately 5 g, preferably from approximately 0.25 g to approximately 1.5 g, of a compound of the present invention.
[0048] The present invention relates especially also to the use of a compound of formula 1 or 1A, as such or in the form of a pharmaceutical formulation with at least one pharmaceutically acceptable carrier for the therapeutic and also prophylactic management of a vascular and metabolic disease, in particular of peripheral arterial disease.
[0049] The preferred dose quantity, composition, and preparation of pharmaceutical formulations (medicines) which are to be used in each case are described above.
[0050] Furthermore, the invention provides a method for the treatment of a metabolic disease, which comprises administering a compound of formula 1 or 1A, wherein the radicals and symbols have the meanings as defined above, in a quantity effective against said disease, to a warm-blooded animal requiring such treatment.
[0051] The following Examples serve to illustrate the invention without limiting the invention in its scope.
EXAMPLES
Example 1
2-{2-(6-[4-(1-Cyclohexyl-1H-tetrazol-5-yl)butoxy]-2-oxo-3,4-dihydroquinolin-1H-yl)-2-oxoethyl}-propane-1,3-diyl acetone diketal (2)
[0052]
[0053] Equivalent amounts of 6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4-dihydroquinolin-2(1H)-one (cilostazol, formula 1, A=H, 554 mg, 1.5 mmol), 4-hydroxy-(3-hydroxymethyl)-butanoic acid dimethyl ketal (261 mg, 1.5 mmol), dicyclohexyl carbodiimide (DCC, 309 mg, 1.5 mmol) and 4-dimethylaminopyridine (DMAP, 183 mg, 1.5 mmol) are stirred in 5 ml CH 2 Cl 2 for 3 days at room temperature. Dicyclohexylurea is filtered off, and the liquid evaporated and purified by chromatography (dichloromethane/diisopropylketone 97.5:2.5). The title compound 2 is obtained in 67% yield.
[0054] 1 H-NMR (400 MHz, CD 3 OD/CDCl 3 9:1): δ 1.27-1.58 (m, 4H), 1.40 (s, 3H), 1.41 (s, 3H), 1.72-2.06 (m, 12H), 2.28-2.37 (m, 1H), 2.66-2.71 (m, 2H), 2.84-2.89 (m, 2H), 3.01 (t, J=7.6 Hz, 2H), 3.05 (d, J=6.7 Hz, 2H), 3.71 (dd, J=7.2, 11.8 Hz, 2H), 3.99-4.07 (m, 2H), 4.31-4.40 (m, 1H), 6.78 (dd, J=2.8, 8.7, 1H), 6.82 (d, J=2.8, 1H), 7.23 (d, J=8.7, 1H).
Example 2
1-[4-Hydroxy-3-(hydroxymethyl)butanoyl]-6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4-dihydroquinolin-2(1H)-one (3)
[0055]
[0056] A mixture of 5 mmol 2-{2-(6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-2-oxo-3,4-dihydroquinolin-1H-yl)-2-oxoethyl}-propane-1,3-diyl acetone diketal (2, Example 1) and 0.10 g FeCl 3 —SiO 2 reagent in 20 mL CHCl 3 is stirred at room temperature. The reaction is monitored by TLC. After completion of the ketal cleavage, the mixture is filtered, and the filtrate concentrated under reduced pressure. The product is purified by flash chromatography.
Example 3
1-[4-Bromo-3-(bromomethyl)butanoyl]-6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4-dihydroquinolin-2(1H)-one (4)
[0057]
[0058] To a solution of 6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4-dihydroquinolin-2(1H)-one (cilostazol, 1, A=H, 2.0 g, 3.50 mmol), N,N-dimethylaminopyridine (0.043 g, 0.35 mmol) and triethylamine (0.5 ml, 0.35 mmol) in THF (100 mL) at 0° C. and under nitrogen, a solution of 4-bromo-3-(bromomethyl)butanoyl chloride (0.97 g, 3.50 mmol) in THF (5 mL) is slowly added and the reaction mixture stirred at room temperature for 2 hours. Then it is partitioned between ethyl acetate and phosphate buffer (pH=3) and extracted with ethyl acetate (3×25 mL). The organic phase is dried over Na 2 SO 4 and concentrated. The crude material is purified by flash chromatography (CH 2 Cl 2 /acetone 7:3).
Example 4
2-{2-(6-[4-(1-Cyclohexyl-1H-tetrazol-5-yl)butoxy]-2-oxo-3,4-dihydroquinolin-1H-yl)-2-oxoethyl}-propane-1,3-diyl dinitrate (5)
[0059]
[0060] 1-[4-Bromo-3-(bromomethyl)butanoyl]-6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4-dihydroquinolin-2(1H)-one (4, 1.5 g, 2.5 mmol, Example 3) is dissolved in CH 3 CN (30 ml), and AgNO 3 (0.93 g, 5.5 mmol) is added in the dark and under nitrogen. The mixture is stirred at 85° C. for 24 hours. Then it is cooled and poured into a phosphate buffer solution (pH=3). Solid sodium chloride is added and the mixture is extracted with ethyl acetate. The organic phase is washed with phosphate buffer (pH=3, 1×25 mL), brine (3×50 mL), dried over Na 2 SO 4 and concentrated. The crude material is purified by flash chromatography (CH 2 Cl 2 /acetone 8:2) affording crude compound, which is dissolved in H 2 O/CH 3 CN and freeze dried to give the desired dinitrate.
[0061] Alternatively, the compound is prepared from the corresponding diol 3 (Example 2) in the following way: 1-[4-Hydroxy-3-(hydroxymethyl)butanoyl]-6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4-dihydroquinolin-2(1H)-one (23.7 g, 0.049 mol) is added slowly to 15 g HNO 3 (100%, 0.24 mol) at −10° C. The resulting mixture is stirred for 10 min at 0° C., 15 g ice added to it, and stirring continued for 2 h at room temperature until brown gases (NO r ) disappear. The mixture is cooled to 5° C., and 2-butanol added carefully. The mixture is neutralized to pH=6 with 15.6 g NaHCO 3 at 0° C. After separation of the phases, the organic phase is dried with MgSO 4 . The resulting crude mixture is purified as above to give the desired dinitrate.
Example 5
1-(4-Chlorobutanoyl)-6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4-dihydroquinolin-2(1H)-one (6)
[0062]
[0063] To a solution of 6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4-dihydroquinolin-2(1H)-one (cilostazol, 1, A=H, 15.00 g, 40.6 mmol), pyridine (6.42 g, 81.2 mmol) and 4-dimethyl-aminopyridine (DMAP, 6.45 g, 52.8 mmol) in 135 mL chloroform at room temperature is added slowly 4-chlorobutanoyl chloride (7.45 g, 52.8 mmol). The mixture is stirred at 70° C. for 20 hours. The reaction mixture is diluted with 1000 mL CH 2 Cl 2 , and washed with 1N HCl, saturated NaHCO 3 solution and brine. The organic phase is dried over sodium sulphate, and concentrated. The residue is purified by flash chromatography (silica gel, CH 2 Cl 2 /tert-butyl methyl ether 90:10) to give the title compound in 42% yield.
[0064] 1 H-NMR (400 MHz, CDCl 3 ): δ 1.25-1.48 (m, 3H), 1.75-1.81 (m, 1H), 1.87-2.01 (m, 1H), 2.28-2.37 (m, 10H), 2.19-2.25 (m, 2H), 2.70-2.73 (m, 2H), 2.83-2.87 (m, 2H), 2.92 (t, J=7.6 Hz, 2H), 3.21 (t, J=7.0 Hz, 2H), 3.67 (t, J=6.4 Hz, 2H), 4.05 (d, J=6.1 Hz, 2H), 4.08-4.17 (m, 1H), 6.72 (d, J=2.9, 1H), 6.75 (dd, J=2.9, 8.8, 1H), 7.29 (d, J=8.8, 1H).
Example 6
1-(4-Nitroxybutanoyl)-6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4-dihydroquinolin-2(1H)-one (7)
[0065]
[0066] 1-(4-Chlorobutanoyl)-6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4-dihydroquinolin-2(1H)-one (6, Example 5, 1.0 g, 2.1 mmol) is dissolved in CH 3 CN (50 mL), and AgNO 3 (0.53 g, 3.15 mmol) is added in the dark and under nitrogen. The mixture is stirred at 75° C. for 12 hours. Then it is cooled and poured into a phosphate buffer solution (pH=3). Solid sodium chloride is added and the mixture is extracted with ethyl acetate. The organic phase is washed with phosphate buffer (pH=3, 1×25 mL), brine (3×50 mL), dried over Na 2 SO 4 and concentrated. The crude material is purified by flash chromatography (CH 2 Cl 2 /acetone 8:2) affording the desired nitrate.
Example 7
1-{4-(6-[4-(1-Cyclohexyl-1H-tetrazol-5-yl)butoxy]-2(1H)-oxo-3,4-dihydroquinolin-1H-yl)-4-oxobut-1-yloxy}-2-pyrrolidinodiazene-2-oxide (8)
[0067]
[0068] 1-(4-Chlorobutanoyl)-6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy)]3,4-dihydroquinolin-2(1H)-one (6, Example 5, 1.0 g, 2.1 mmol) is dissolved in CH 3 CN (50 mL) and treated with 1.5 equivalents of sodium pyrrolidinyl diazeniumdiolate (0.48 g, 3.15 mmol). The reaction mixture is stirred for 2 days at room temperature until starting material is totally consumed as indicated by TLC. Then the mixture is concentrated and the residue is dissolved in 50 mL ethyl acetate. The organic solution is washed with water (3×50 mL) and dried over anhydrous Na 2 SO 4 . After removal of the solvent the crude product is purified by silica gel chromatography eluting with a solvent mixture of ethyl acetate and hexane. The product is obtained as a colorless syrup.
Example 8
1-(2-Nitroxyethylaminocarbonyloxymethyl)-6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4-dihydroquinolin-2(1H)-one (9) and 1-[N-(2-nitroxyethyl)-N-(2-nitroxyethyl-aminocarbonyloxymethyl)-aminocarbonyloxymethyl]-6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4-dihydroquinolin-2(1H)-one (10)
[0069]
[0070] To a solution of 6-[4-(1-cyclohexyl-1H-tetrazol-5-yl)butoxy]-3,4-dihydroquinolin-2(1H)-one (cilostazol, 1, A=H, 1.00 g, 2.71 mmol) in dry THF (12 mL) NaH (60% in mineral oil, 0.217 g, 5.41 mmol) is added at room temperature under an argon atmosphere. The reaction mixture is heated to reflux for 30 min, then cooled to 0° C. A solution of chloromethyl 2-(nitroxy)ethylcarbamate (1.075 g, 5.41 mmol, obtainable from 2-nitroxy-ethyl ammonium nitrate and chloromethyl chloroformate in CH 2 Cl 2 at 0° C. in 80% yield) in THF (1.3 mL) is added dropwise at 0° C., and the reaction mixture stirred for 1 h at room temperature. The reaction mixture is carefully quenched with water (5 mL), and THF removed on a rotary evaporator. The resulting aqueous mixture is extracted with CH 2 Cl 2 (3×50 mL). The combined organic layers are dried (MgSO 4 ), and solvent removed under vacuum to leave a yellow oil. The crude product is purified by column chromatography (silicagel, heptanes/ethyl acetate 1:9) to give the title compound 9 in 19% yield as a colourless oil.
[0071] 1 H NMR (CDCl 3 ): δ 6.95 (d, J=10, 1H), 6.7-6.6 (m, 2H), 5.8 (br s, 2H), 5.4 (t, J=7, 1H), 4.5 (t, J=7, 2H), 4.1-4.0 (m, 1H), 3.9 (t, J=7, 2H), 3.55-3.45 (m, 2H), 2.9-2.7 (m, 4H), 2.6-2.5 (m, 2H), 2.0-1.6 (m, 11H), 1.4-1.2 (m, 3H).
[0072] 13 C NMR (CDCl 3 ) δ: 171.3, 155.8, 155.5, 153.9, 132.9, 128.1, 116.6, 114.9, 113.4, 72.1, 68.4, 67.9, 58.0, 38.8, 33.3, 32.2, 28.9, 25.9, 25.7, 25.2, 24.3, 23.4.
[0073] LCMS: 554 (M+Na).
[0074] Compound 10 carrying two nitroxyethylaminocarbonyloxymethyl functions is obtained as a side product in 5% yield:
[0075] 1 H NMR (broad peaks due to carbamate rotamers, CDCl 3 ): δ 6.95 (1H), 6.7-6.6 (2H), 5.8 (2H), 5.4-5.1 (3H), 4.6-4.4 (4H), 4.1-4.0 (1H), 3.9 (2H), 3.8-3.6 (2H), 3.5-3.45 (2H), 2.9-2.7 (4H), 2.6-2.5 (2H), 2.0-1.6 (11H), 1.4-1.2 (3H).
[0076] 13 C NMR (CDCl 3 ): δ 171.0, 156.1, 155.5, 154.8, 153.9, 132.6, 128.0, 116.3, 114.5, 113.2, 73.2, 72.0, 70.0, 69.5, 67.7, 57.8, 45.5, 38.6, 33.1, 32.0, 28.9, 25.7, 25.5, 25.0, 24.1, 23.2.
[0077] LCMS: 716 (M+Na)
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Nitrate derivatives of cilostazol are described. They have superior properties and clinical advantages compared to cilostazol in the treatment of vascular and metabolic diseases.
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CROSSREFERENCES TO RELATED APPLICATIONS
[0001] This application claims priority from German patent application 10 2015 112 510.2, filed on Jul. 30, 2015. The entire content of this priority application is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The invention relates to a grinding tool for a grinding device comprising an oscillatory drive, in particular a rotary oscillatory drive the drive shaft of which can be driven oscillatingly about its longitudinal axis, wherein the grinding tool comprises a holder comprising a support for securing to the drive shaft of the oscillatory drive, and whereon a form profile including a grinding means is received.
[0003] Such a grinding tool is known from WO 2004/076125 A1.
[0004] Such a grinding tool allows a grinding along longitudinal edges, in particular of profiles etc., even in view of the fact that for driving an oscillatory drive is used the rotary shaft of which is driven oscillatingly. By using an elastic grinding pad it is ensured that strong vibrations of the grinding tool are avoided despite of the grinding surface being straight at least in one direction. A grinding means configured as a grinding paper can be secured to the grinding pad by means of a suitable clamping device.
[0005] Detrimental is the relatively inconvenient clamping of the grinding paper onto the grinding pad. In addition the grinding tool consists of several individual part which must be put together.
SUMMARY OF THE INVENTION
[0006] In view of this it is a first object to disclose an improved grinding tool for a grinding device with a oscillatory drive.
[0007] It is a second object of the invention to disclose a grinding tool for a grinding device with a oscillatory drive that can be attached in a very simple way.
[0008] It is a third object of the invention to disclose a grinding tool for a grinding device with a oscillatory drive including a holder whereon a grinding paper can be attached in a very simple way.
[0009] It is a forth object of the invention to disclose a grinding tool for a grinding device with a oscillatory drive including a holder that allows for an easy handling.
[0010] It is a fifth object of the invention to disclose an improved grinding tool that can be produced in a simple and cost-effective manufacture.
[0011] According to a first aspect of the invention these and other objects are solved by a grinding tool for a grinding device comprising an oscillatory drive, the drive shaft of which can be oscillatingly driven about its longitudinal axis, said grinding tool comprising:
[0012] a holder including a support for securing to said drive spindle of said oscillatory drive;
[0013] a form profile including a grinding agent being received on said holder;
[0014] a profile support provided on said holder for releasably securing said form profile, said profile support comprising a clamping region being configured for receiving and securing a holding section provided on said form profile when inserting said holding section into said clamping region, said clamping region being further configured for being elastically enlarged to allow a release of said form profile secured within said clamping region.
[0015] According to the invention the grinding tool consists only of the holder and the form profile which can be secured to each other. In addition a grinding paper can be secured to the form profile. Alternatively the form profile may be equipped with an abrasive surface.
[0016] All in all in this way a particularly simplified design results, a cost-effective manufacture and an exchange possibility for the form profile, in case the letter is worn down or a different form profile is desired. In addition by means of the simplified design and the abandonment of the spring elements consisting of a spring steel a considerable mass reduction results when compared to the prior art. In this way an improved grinding performance can be reached due to the smaller moment of inertia.
[0017] According to another aspect of the invention at the clamping region there is attached at least one handle part for elastically enlarging the clamping region.
[0018] In this way the clamping region can be simply elastically enlarged by applying pressure onto the at least one handle part to thus allow to release the form profile and the grinding paper from the clamping region in a particularly simple way or to insert into the latter.
[0019] According to a further configuration of the invention the clamping region comprises an elastically enlargeable cavity into which the form profile can be inserted with its holding section and can be secured under the action of the internal stress of the clamping region.
[0020] In this way the internal stress of the clamping region is used to allow a safe securement of the form profile with its holding section at the clamping region of the holder.
[0021] Herein the form profile can be held frictionally engaged with its holding section within the cavity of the holder.
[0022] In this way only the internal stress of the holder within its clamping region is used to ensure a frictionally engaged securement of the form profile at the holder.
[0023] Alternatively or in addition the form profile may be held positively secured with its holding section within the cavity of the holder, preferably may be click-secured, wherein the positive locking or the click-securement can be released by elastically enlarging the cavity.
[0024] In this way a particularly secure fixation of the form profile at the holder is ensured.
[0025] According to a further development of the invention the clamping region at both axial ends of the cavity is limited by end sections wherein between the two end sections on both sides side sections extend which are spaced from the end sections.
[0026] In this way the side sections can be configured spring-elastically to thereby allow a high internal stress whereby a safe securement of the form profile with its holding section within the profile support is made possible.
[0027] According to a further development of the invention the cavity comprises a substantially U-shaped cross-section.
[0028] With such a design the internal stress of the clamping region for securing the form profile can be ensured in a particularly simple way.
[0029] According to a further design of the invention at a first one of the two side sections at least one gripping part is attached.
[0030] Preferably herein at the first side section two gripping parts are attached which extend from the side sections slanted to the outside.
[0031] By using one or several gripping parts at the first side section an elastic deformation of the clamping region can be ensured simply by exerting pressure, to allow for an exchanging the form profile.
[0032] Herein the first side section starting from the bent section may yield into a plane section whereon the at least one gripping part is attached from the outside.
[0033] The plane section herein preferably serves for direct positioning against the form profile. By contrast the bent section facilitates an elastic deformation upon application of a respective tensile or pressure force.
[0034] The end sections that limit the cavity at both axial ends according to a preferred development of the invention each comprise an end face, and thereby interrelated side extensions substantially formed perpendicularly thereto which are each spaced from the adjacent first and second side sections by a slot.
[0035] Such a design allows to receive and to guide an inserted form profile at the end sections, while by the spacing of the first and second side sections by means of a slot the elasticity of which can be ensured to allow for an elastic enlargement of the surrounded cavity for exchanging the form profile.
[0036] According to a further preferred development of the invention at the end sections stops are provided for limiting the insertion depth of the form profile into the cavity.
[0037] In this way a precise positioning of the form profile is ensured.
[0038] According to a further development of the invention the form profile is coated with a grinding agent at least at a part of its outer surface.
[0039] In this way a grinding is made possible directly using the outer surface of the form profile.
[0040] According to a further development of the invention the form profile is configured for receiving a grinding paper which can be secured together with the form profile within the cavity of the holder.
[0041] In this way after a wear-down of the form profile not the complete form profile must be disposed of. By contrast during grinding the grinding paper is worn which can be easily exchanged.
[0042] Herein the grinding paper preferably has dimensions adapted to the outer surface of the form profile so that the grinding paper at least partially wraps around the outer surface of the form profile and is held with both ends between the holding section of the form profile and the side sections of the holder.
[0043] In this way a simple securement of the grinding paper is made possible.
[0044] According to a further development of the invention the grinding paper in the clamped state is pressed at each of its ends facing the holder into a depression which is formed in the assigned side sections of the holder.
[0045] In this way an improved holding force for the grinding paper can be reached.
[0046] According to a further development of the invention the form profile consists of an elastically yielding material, such as polyurethane foam for example.
[0047] Such a material design facilitates a grinding along longitudinal edges and longitudinal profiles, since vibrations can be partially offset in this way.
[0048] According to a further development of the invention the holder is made unitary from a plastic material, preferably as an injection molded part.
[0049] This allows for a simple and cost effective manufacture and a particularly favorable design of the clamping region which is elastically enlargeable for releasing the form profile.
[0050] According to a further development of the invention at both side sections of the holder on the surface facing the form profile webs are provided to which grooves at the form profile are assigned.
[0051] Thereby a positive securement of the form profile is ensured so that during a grinding process a lateral yielding is avoided.
[0052] The support of the holder preferably is configured for positive connection with the drive spindle of the oscillatory drive.
[0053] To this end suitable embosses of the support or assigned adapters can be provided to ensure a direct mating to an assigned positive fitting support at the drive spindle.
[0054] According to a further development of the invention the support of the holder defines a longitudinal axis, wherein the form profile extends at least in one direction of extension straight and perpendicularly to the longitudinal axis of the support.
[0055] By such a design a grinding longitudinal profile is made possible.
[0056] It is understood that the afore mentioned features and the features of the invention to be explained hereinafter can it only be used in the given combination, but also in different combinations or independently, without departing from the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0057] Further features and advantages of the invention can be taken from the subsequent description of preferred embodiments with reference to the drawings. In the drawings show:
[0058] FIG. 1 a perspective view of a grinding tool according to the invention;
[0059] FIG. 2 the grinding tool according to FIG. 1 which is secured to an assigned drive spindle of an oscillatory drive in its application position;
[0060] FIGS. 3 a -3 c an explosive representation of the individual parts of the grinding tool comprising a holder according to FIG. 3 a , a form profile according to FIG. 3 b and an assigned grinding paper according to FIG. 3 c;
[0061] FIG. 4 a top view of the holder according to FIG. 3 a;
[0062] FIG. 5 a cross section through the holder according to FIG. 4 along the line V-V;
[0063] FIG. 6 a plan view of the holder according to FIG. 4 seen from the bottom;
[0064] FIG. 7 a longitudinal section through the grinding tool according to FIG. 1 ; and
[0065] FIG. 8 a perspective cross section of the grinding tool according to FIG. 7 .
DESCRIPTION OF PREFERRED EMBODIMENTS
[0066] A grinding tool according to the invention is shown in FIG. 1 in perspective and designated in total with numeral 10 . The grinding tool 10 comprises a holder 14 at which a form profile 16 and a grinding means 18 configured as a grinding paper are supported.
[0067] The grinding tool 10 is configured for utilization with a oscillatory drive of known design, such as shown schematically in FIG. 2 . The oscillatory drive 20 comprises a drive spindle 22 which can be driven about its longitudinal axis 24 in rotary oscillating fashion at high frequency in the range of about 10.000 to 25.000 oscillations per minute and with a small pivot angle of about ±0.5 to ±5°. The grinding tool 10 is secured positively at the outer end of the drive spindle 22 with a suitable support and is safeguarded by means of a securing element 26 .
[0068] The grinding tool 10 serves in particular for grinding longitudinal profiles and longitudinal recesses. To this end the form profile 16 and the assigned grinding means 18 are supported exchangeably at the holder 12 as will explained in more detail in the following. The shape of the form profile 16 expediently is adjusted to the longitudinal profile that is to be ground. Thus different form profiles with different cross sections may be provided which are secured exchangeably to the holder 12 . In the case shown in FIG. 1 the form profile 16 comprises several flat formed surfaces which are arranged at an angle to each other. Herein a plane designed front face 19 of the form profile 16 extends perpendicularly to the longitudinal axis 24 of the drive shaft 22 , and thus also perpendicularly to the longitudinal axis 60 which is defined by the support 14 of the holder 12 .
[0069] The more detailed design of the grinding tool 10 now will be explained with reference to FIGS. 3 to 8 .
[0070] From FIGS. 3 a -3 c it can be seen that the grinding tool 10 is made up at least of two parts, possibly of three parts. In any case to this end a holder 12 with a support 14 is configured for connection with the drive spindle 22 ( FIG. 2 ). At the holder 12 the form profile 16 together with a suitably shaped grinding means 18 being configured as a grinding paper can be secured. The form profile 16 according to a first design at its surface may be provided with a grinding agent to thus allow a grinding directly with the form profile 16 . Alternatively also a separate grinding means 18 configured as a grinding paper may be provided, the shape of which is adapted to the shape of form profile 16 and which can be secured together therewith at the holder 12 .
[0071] The holder 12 consists of a rigid plastic material and comprises a clamping region 36 having a cavity 38 into which the form profile 16 can be inserted with an assigned holding section 40 and can be secured thereto. To ensure a force transmittance between the drive spindle 22 and the holder 12 , within the support 14 a driving disk 30 made of metal, in particular of steel, is molded (cf., FIG. 1, 3, 7, 8 ) that allows for a positive force transmittance to the drive spindle 22 . To this end suitable recesses 32 are provided at the driving disk.
[0072] The clamping region 36 comprises two side sections 46 , 48 facing each other which are connected in one piece with the holder 12 . The axial ends of the cavity 38 are closed by end sections 42 , 44 , wherein respectively one flat end face and two side extensions 53 , 54 facing each other are provided. Between the end sections 43 , 44 the side sections 46 , 48 are enclosed which each are divided from the end sections 42 , 44 by a slot 66 . This leads to the consequence that the two side sections 46 , 48 facing each other that are only connected at there inner ends with the holder 12 can be enlarged relative to each other.
[0073] To this end at the first side section 46 there are provided two gripping parts 50 , 51 extending slanted to the outside. In case pressure is exerted onto the gripping parts 50 , 51 from the outside, then the first side section 46 can be slightly widened to the outside relative to the second side section 48 to thus allow an insertion of the form profile 16 into the cavity 38 of the holder, or a withdrawal of the form profile 16 with its holding section 40 from the cavity 38 .
[0074] In addition at the inner surfaces of the first side section 46 and the second side section 48 there may be provided webs 56 extending in insertion direction of the form profile 16 , to which respective grooves 58 are assigned at the holding section 40 of the holder 12 .
[0075] In this way during insertion of the form profile 16 with its holding section 40 into the cavity 38 of the holder 12 , a positive support is made possible which impedes a shifting of the form profile 16 in longitudinal direction.
[0076] If the form profile 16 shall be inserted with its holding section 40 into the cavity 38 of the holder, only pressure must be exerted onto the two gripping parts 50 , 51 , whereby the first side section 46 enlarges to the outside relatively to the second side section 48 .
[0077] Now the form profile 16 can be slid with its holding section 40 into the cavity 38 and is guided herein by the grooves 58 and the assigned webs 56 . If the form profile 16 is slid sufficiently deep into the cavity 38 or abuts therein, then the gripping parts 50 , 51 are released, whereby the form profile 16 is safely secured within the clamping region 36 under the action of the internal stress of the clamping region 36 .
[0078] If a separate grinding means 18 configured as a grinding paper according to FIG. 3 c is used, then this comprises a flat contour according to FIG. 3 c which preferably at both side faces facing each other is pressed into a recess 64 ( FIG. 1 ) which is shaped so that the two side sections 46 , 48 of the holder 12 can directly interfere to thus ensure a safe securement of the grinding means 18 . The grinding means to this end is placed onto the form profile 16 and is inserted together therewith into the widened clamping region 36 of the cavity 38 , and thus is secured together with the form profile 16 . Herein the shape of the grinding means 18 adjusts to the outer shape of the form profile 16 .
[0079] The form profile 16 preferably consists of a yielding plastic foam, such as a polyurethane foam, to allow for a suitable yielding of the form profile during grinding.
[0080] While FIG. 6 shows the holder 12 from the bottom without the adaptor 30 , from FIG. 7 a longitudinal section and from FIG. 8 a perspective longitudinal section through the grinding tool 10 can be seen.
[0081] As can be seen in particular from FIGS. 5 to 8 , the first side section 46 is received at the body of the holder 14 with a bent section 68 which subsequently yields into a flat section 70 . The opposite second side section 48 comprises a flat section 72 facing the first flat section 70 and at its inner end has a stop 74 formed perpendicularly therein serving as a stop when inserting the form profile 16 .
[0082] The holder 12 is prepared as an injection molded part from a rigid plastic material (e.g. PVC). Thus a cost effective manufacture at high quantities and the same time an elasticity of the clamping region 36 is made possible.
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A grinding tool for a grinding device with an oscillatory drive, in particular a rotary oscillatory drive is disclosed, the drive shaft of which can be driven about its longitudinal axis, wherein the grinding tool includes a holder having a support for securing to the drive shaft of the oscillatory drive, and whereon a form profile with a grinding mechanism is provided, wherein the holder includes a profile support for releasable securement of the form profile, and wherein the profile support includes a clamping region, into which the form profile can be inserted with a holding section and can be fixed thereto, and which can be elastically enlarged for releasing the form profile.
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FIELD OF THE INVENTION
The field of the invention is top down cementing and more particularly with fluid displacement by the cement through a crossover with the ability to rotate the liner while cementing and further provisions for setting a liner hanger and release of a running tool from the cemented liner.
BACKGROUND OF THE INVENTION
Traditional liner cementing involves delivery of cement through a liner that is hung off casing with the cement going through a cement shoe at the lower end of the liner and back around in the annular space around the suspended liner. Fluid is displaced by the advancing cement through the liner hanger. At the time of fluid displacement with cement, the seal on the liner hanger is not set and there are gaps between the anchor slips through which the displaced fluid moves. After the cement is delivered a trailing wiper plug is released to clear the liner of excess cement. The cement shoe has a check valve to prevent return of the cement. The seal on the liner hanger is then set and the liner running tool is released and pulled out of the hole. The shoe can be milled or drilled out and more hole can then be drilled and the process can be repeated.
In some situations there can be doubt that the cement is adequately distributed using this method and an alternative technique for cement placement is desired. This is particularly beneficial when a formation is particularly weak which can result in significant fluid loses due to low fracking gradients. In a top down delivery of cement the operating pressures to which the formation is exposed are far less than the traditional bottom up cementing which can be beneficial in minimizing impact on the formation and ultimately getting a higher production rate from the formation when the well is put into production.
While there has been talk in the industry of doing top down cementing as a concept there have been no disclosed tools that would successfully and reliably accomplish such a cementing method. At best, schematic drawings for the flow of cement and return flows are illustrated in discrete passages with no clear details of how such tools get reconfigured for the various positions needed to actually accomplish top down cementing. Some examples of this are U.S. Pat. No. 8,387,693 FIG. 117 and the associated discussion in one paragraph in the specification and US 2010/0155067 that mentions ports such as 44 and seal bores in a passing reference to top down cementing with little detail as to how the tool is reconfigured for running in and then cementing and no details how to accomplish any associated tasks such as rotation while cementing, setting a liner hanger and releasing a running tool or how to structure a crossover tool and reconfigure such a tool between cement placement and the need to set a liner hanger/packer after cementing.
A top down cementing tool operates with either mechanical manipulation or hydraulically with rotation of the liner during cementing enabled. A first bore is open for circulation during running in of the liner. In the hydraulic version, pressuring up on a dropped ball in the first bore opens cement packer setting ports and aligns crossover ports from the first bore to the annulus below the cementing packer and displaced fluid return ports to the annulus above the cementing packer. Pressuring up on a trailing wiper plug in the first bore opens the second bore so that pressuring on a seated ball in the second bore opens access to unsetting the cementing packer and launching the ball in the second bore for liner hanger setting and release of the running tool. The alternative embodiment gets the same result but with string manipulation for some of the realignments.
Embodiments are presented that operate hydraulically and mechanically to get the same result. In either case, rotation of the liner during cementing is enabled. Those skilled in the art will better understand additional aspects of the present invention from a review of the detailed description of the preferred embodiments and the associated drawings while recognizing that the full scope of the invention can be found in the appended claims.
SUMMARY OF THE INVENTION
The present invention presents alternative embodiments to make top down cementing a reality. The basic interpretation of the invention switches from the conventional flow pattern to a crossed over flow pattern and then back to a conventional flow pattern. The invention uses a dual bore mandrel to allow internal flow in both the upward and downward directions during cementing. During run-in of the tool the invention has flow isolated to the Inlet bore. Both bores of the dual bore mandrel have ports. The inlet bore has ports below the packer element and the return bore has ports above the packer element. The ports on both bores are blocked from allowing flow to pass through them during the run in position. A ball will be dropped to set a cementing packer that will isolate the crossover ports for inserting the cement from those used to allow bypass for the return fluid. Manipulation of the tool through hydraulic or mechanical actuation opens the bypass ports allowing the transition from conventional flow to cross over flow. Flow rates are established at this time and then the cementing operations are performed. During cementing the tool can be rotated through the packer so a more even application of the cement occurs. At the end of the cementing operations the inlet bore is closed off by a sealing object dropped from surface and pressure can be increased to open the upper end of the return bore allowing the return a conventional flow path. Hydraulic or mechanical actuation is then performed to isolate the return ports so flow is blocked through them. Additional hydraulic or mechanical manipulation will unset the packer element allowing external bypass. Further hydraulic or mechanical actuation can then be performed to send a preloaded object from within the tool to set the liner string below and release the running tools allowing detachment and retrieval of the proposed tool. Standard cleaning operations for removing excess cement from the top of the liner can be done through the return fluid bore because the flow has been returned to conventional flow path.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 a -1 e are the hydraulic embodiment of the tool in the run in position;
FIGS. 2 a -2 e are the view of FIGS. 1 a -1 e in the packer setting position;
FIGS. 3 a -3 e are the view of FIGS. 2 a -2 e in the crossover flow configuration;
FIGS. 4 a -4 e are the view of FIGS. 3 a -3 e in the unset packer configuration;
FIGS. 5 a -5 e are the view of FIGS. 4 a -4 e in the release ball configuration for setting the liner hanger/packer below and releasing for running tool removal;
FIGS. 6 a - i is an alternative embodiment in the run in position;
FIGS. 7 a - i is the view of FIGS. 6 a - i in the packer set position;
FIGS. 8 a - i is the view of FIG. 7 a - i in the cementing position; and
FIGS. 9 a - i is the view of FIGS. 8 a - i in the packer release and set the liner hanger/packer position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1 a -1 e show the fully hydraulic embodiment of the present invention in the run in position. The top down cementing tool T sits inside the previous casing 12 . The liner and associated hanger/packer are below and are not shown. The liner hanger/packer are a known design and operate in a known manner including the setting and the release from the top down cementing tool T.
The major components of the tool T are a cementing packer P, an inlet bore 14 , a return bore 16 , an isolation sleeve 36 , a cement crossover port 20 , a returns crossover port 22 , a packer actuation port 24 , a packer release port 26 and a liner hanger/packer actuation ball 28 . For running in the isolation sleeve 36 has no ball 30 so that circulation is possible down inlet bore 14 to its lower end 32 where the flow can then enter the liner and come back to the surface in the annular space outside the liner.
When the liner is properly located generally at the lower end of the previous casing 12 the ball 30 is delivered to seat 18 as shown in FIG. 2 e . Pressure in bore 14 shears pin 34 and shifts sleeve 36 with ports 38 such that ports 38 align with actuation port 24 so that applied pressure moves piston 42 in the direction of arrow 44 toward the packer element 78 , after breaking shear pin 45 , to set the packer P. During shifting of sleeve 36 to align ports 38 with actuation port 24 , lower end 48 of sleeve 36 lands on upper end 50 of sleeve 52 which is in turn connected to sleeve 54 at thread 56 for tandem movement as will be later described. Sleeve 54 has the lower end 32 of the bore 14 . Sleeve 54 also has a lateral opening 58 that is misaligned with opening 60 in sleeve 62 . The lower end of sleeve 62 has a diverter plug 64 to block flow until opening 58 and opening 60 align. A travel stop 66 is in the bottom sub 68 of tool T. Openings 58 and 60 ultimately align to form bypass 61 seen in FIG. 3 e as sleeve 54 is driven to the travel stop 66 by additional pressure on ball 30 which breaks shear pins 80 . Sleeve 62 remains fixed to facilitate the alignment between openings 58 and 60 .
In the FIG. 2 position with ports 38 aligned with actuation port 24 that is closed with thermal and pressure compensating piston 72 an isolated chamber 40 that has atmospheric or low pressure hydraulic fluid. The pressure buildup in chamber 40 moves piston 42 in direction 44 and the seal assembly 78 of the cement packer P is compressed. At this time the cement exit ports 76 are still offset from crossover ports 20 but further pressuring up after the packer P is set moves abutting sleeves 36 , 52 and 54 to break shear pin 80 . When that occurs ports 76 move into alignment with ports 20 so that when cement is delivered to bore 14 it can exit laterally. The cement is delivered after a leading dart 70 lands on ball 30 as shown in FIG. 3 d - e . Ports 82 in the bore 16 have been run in aligned with housing crossover ports 22 , which is where the displaced fluid exits above the now set sealing element 78 . The rupture disc 26 is still intact so that in FIG. 3 as the cement is delivered into bore 14 it travels to the aligned ports 76 and 20 to make a lateral exit because bore 14 is now closed with dart 70 sitting on seated ball 30 on seat 18 . This cement flow is shown by arrow 84 . At the same time heavy fluid that has been pumped in advance of the cement to help retain the cement in the annular space about the liner without entering the liner is displaced ahead of the cement into bore 16 because the cement pressure on ball 30 keeps bore 14 closed and the returning heavy fluid enters bore 16 as indicated by arrows 86 . The displaced fluid then crosses over through aligned ports 82 and 22 as indicated by arrow 88 .
After the predetermined volume of cement is delivered in the FIG. 3 configuration, the next steps are to set the liner hanger/packer that is not shown and to release the tool T from the cemented liner that is also not shown. To do this, a second dart 90 lands on seat 92 at the end of the cementing operations so that the aligned ports 76 and 20 are effectively isolated from the upper end 94 of the bore 14 . Pressure is now applied to break the rupture disc 26 to open up passage 96 that leads to passage 16 . The ensuing flow into passage 96 is further impeded by the no shock sleeve 100 . A metering device 98 allows hydraulic fluid in space 101 to pass slowly so that ball or sealing object 118 does not get released early from ball seat 122 . The newly opened passage 96 allows for the pressuring up on the back end of the no shock sleeve assembly 100 which will break shear pin 108 allowing the no shock sleeve assembly 100 to be shifted until it shoulders out on travel stop 102 . Such movement opens up ports 104 as seal 106 shifts past port 104 . Pressure applied into annular passage 110 moves piston 112 in the direction of arrow 114 to release and extend the seal assembly 78 of packer P. Initial movement of the piston 112 breaks shear pins 116 allowing further movement of piston 112 . The further movement of piston 112 also releases a snap ring 113 by pulling out retaining key 117 to allow springs 115 to retract seal element 78 from contact with the previous casing 12 . Further movement of piston 112 in the direction of arrow 114 will shift port 22 to be misaligned with port 82 blocking off flow path 88 . Piston 112 will travel in the direction of arrow 114 until it shoulders out on travel stop 119 . This pressure buildup to release the cement packer P can happen because the ball 118 is still seated on frangible seat 122 through which ball 118 will ultimately pass when enough pressure is applied. Once piston 112 has shifted until it has shouldered out on travel stop 119 , the remaining hydraulic fluid left in space 101 is pushed through metering device 98 aligning ports 120 with ports 121 to increase flow bypass through the no shock sleeve assembly 100 . When ports 120 and 121 align collet 129 will latch onto shoulder 125 which locks ports 120 and 121 in alignment. With the cementing packer P unset further pressure buildup will force ball 118 through seat 122 as shown in FIG. 5 so that the released ball 118 will land in the liner hanger/packer that is not shown for setting it in a known manner and for releasing the tool T also in the known manner. The tool T is now pulled out of the hole and excess cement can be washed out through the standard flow path through passage 96 and bore 16 from tubular to annular flow. Cement is then allowed to set up after which the hole can be extended and the process repeated with another liner or the hole can be completed and put into production.
Rotation of the tool T with the packer P set is enabled by bearings 121 , 123 , 131 , and 132 which allow all the components not fixated by the sealing effect of the seal assembly 78 , when set, to relatively rotate while the cement is delivered. Rotary seals 133 and 134 beneath packer P allow for a pressure differential across packer P while relative rotation occurs between packer P and dual bore mandrel 15 .
FIGS. 6-9 is another embodiment that has some similarities to the embodiment described above but has some mandrel manipulation to assume the necessary positions for accomplishing top down cementing. It will be described in a more abbreviated manner assuming the detailed discussion above of the first embodiment has provided a general background as to the tool configuration for top down cementing.
A mandrel 200 supports an outer housing 202 on opposed bearings 204 and 206 so that when a cementing packer 208 is set, the mandrel 200 can rotate relatively to the outer housing 202 components held fixed by the set packer 208 . Inside the mandrel 200 is a body that defines the cementing bore 210 and the displaced fluid bore 212 . A rupture disc 214 isolates the top of bore 212 from bore 210 at junction 216 . Bore 210 has lateral openings 218 located between seals 220 and 222 for access through ports 224 and 225 to set the packer 208 . This is done by pushing up the pistons 226 and 227 , and locking the piston movement with lock ring 228 so that the sealing element 230 is against the surrounding casing 232 . Bore 210 can be pressurized by landing ball 234 on seat 236 and building pressure. At a predetermined pressure the packer 208 is set and the seat 236 moves against tubular travel stop 238 so as to release the flapper 240 that is spring loaded to rotate against a seat 242 . With flapper 240 on the seat 242 flow up bore 210 is cut off.
The mandrel 200 is split into two components: an axial shifting mandrel 201 and a rotary sleeve 203 . The axially shifting mandrel 201 can shift axially with respect rotary sleeve 203 but are rotationally locked by torque stinger 205 and lock block 207 . The rotary sleeve 203 portion of mandrel 200 is axially locked to the outer housing 202 through retainers 209 and 211 which support bearings 204 and 206 . The axial shifting mandrel 201 is picked up to the point of collet 248 landing in groove 250 as shown in FIG. 8 b . This movement raises openings 252 in bore 210 to slots 254 in the axially shifting mandrel 201 where the slots 254 were already aligned with openings 256 in the outer housing 202 . The same picking up movement of axial shifting mandrel 201 lifts openings 260 in bore 212 that are located between seals 262 and 264 into alignment with slots 266 which are already aligned with openings 268 in outer housing 202 as shown in FIG. 8 c . A second ball 244 is dropped on seat 246 , as shown in FIG. 8 e to block off any additional flow from passing by the flapper 240 and shifts seat 246 until it shoulders out on travel stop 241 . A dart 258 is landed on ball 244 prior to pumping cement. At this time, after the heavy fluid is delivered the cement can be delivered right behind the heavy fluid to exit laterally as indicated by arrow 270 keeping in mind that the second dart 272 is delivered behind the predetermined quantity of cement. This effectively closes ports 252 with dart 272 as shown in FIG. 9 e . The displaced fluid comes up bore 212 because flapper 240 closes off bore 210 to flow in the up-hole direction. Arrow 274 shows the crossover exit of this fluid above the seal 230 for the trip up-hole in the upper annulus above the cement packer 208 .
After port 252 has effectively been closed off, rupture disc 214 is broken with applied pressure and the axial shifting mandrel 201 is lifted to take collet 248 out of groove 250 until travel stop 276 is engaged as shown in FIG. 9 . Several processes take place during this lifting of the axial shifting mandrel 201 . First, the lower ports 252 and 254 are misaligned closing off flow to below the packer. At the same time, the upper ports 260 and 266 are misaligned closing off flow above the packer. At the same time the mandrel assembly 301 gets rotationally locked to the rotary sleeve 203 by the engagement of tooth pattern 304 to respective pattern 306 with 306 held by drag blocks 308 . Furthermore there is a lower travel stop 300 that limits the downward movement of the mandrel assembly 301 with respect to the axial shifting mandrel 201 . It should also be noted that lifting the axial shifting mandrel 201 disengages a mandrel spline 302 at the bottom end of the mandrel assembly 301 to permit the relative rotation of the axial shifting mandrel 201 with respect to the mandrel assembly 301 for ejection of ball 280 through opening 278 described later. Furthermore, picking up the axial shifting mandrel 201 , as shown in FIG. 9 , also rotationally releases the axial shifting mandrel 201 from the rotary sleeve 203 by disengaging the rotational lock between the torque stinger 205 and lock block 207 . With additional pickup, the packer 208 is released, seen in FIG. 9 , by breaking a shear ring 310 that defeats the collet thread 229 to physically extend the packer 208 in a known manner. Once the packer 208 is released the setting of the liner hanger and packer can take place. The preferred way to set the liner hanger/packer is by release of dart or ball 286 . The same pickup force that engaged lower travel stop 300 undermines support for flappers 288 and 290 by respectively aligning grooves 292 and 294 momentarily as the relative movement occurs. When flappers 288 and 290 have been removed from the darts path it can then be pumped down to set the liner tools below. It should be noted that in the run in position of FIG. 6 there is a bypass around the dart 286 from entrance 296 to exit 298 as shown in FIG. 6 h . The same pick up that released the flappers 288 and 290 also moves outlet hole 278 up to ball 280 that is still held out of bore 281 by a retainer 282 . There is a cam surface 284 which when rotated against ball 280 can push ball 280 through the retainer 282 so it can drop to the liner hanger/packer that is not shown for its operation with applied pressure on the seated ball 280 . The setting of the liner hanger/packer that is not shown also allows the release of the tool for pulling out of the hole.
Those skilled in the art will appreciate that the embodiments of the present invention to enable top down cementing. The tool is run down with circulation enabled for location of the liner. The cementing bore is isolated at the top from the displaced fluid bore and running in an object into the cementing bore allows pressuring up to set the cement packer. Further manipulation aligns the cement crossover exit ports to ports leading out of the tool below the set cement packer. At this time the fluid return ports through the tool body from the return bore are already aligned or are being aligned. At the same time a dart is dropped on the ball used to set the packer and cement can be delivered with displaced fluid crossing over from the other bore at a location above the packer that is set to an upper annulus. The cementing crossover ports are then blocked with a second dart so that built up pressure can break a rupture disc and open up the return bore at the top of the cementing bore that is now closed. As the rupture disc breaks a sleeve with a metering device and a seated ball move in tandem. This movement exposes a packer release port leading to a release cylinder. Pressuring on the cylinder actuates the movement that releases a spring housing to extend the packer to retract the seal. The shifting of the cylinder also closes off the crossover port for returns from the displaced fluid bore. With lateral openings from the displaced fluids bore closed, pressuring on the ball in the displaced fluids bore launches this ball through its seat to the liner hanger packer that is not shown so that the liner hanger can be set and the top down cementing tool can be released and pulled out of the hole.
In the alternative embodiment of FIGS. 6-9 the tool is open for circulation during running in. A ball is dropped on a seat and pressured on to sets the packer. Additional pressure is applied to release a flapper that prevents up-hole flow in the cementing bore. A pickup force aligns the cement crossover exit ports from the cementing bore with the displaced fluid crossover exit ports already in alignment. A ball and dart are landed and cement is pumped through the cement bore and out of the tool and displaced fluids cross over above the set cementing packer. A second dart then blocks the cement crossover exit ports and pressuring up on the cement bore then breaks a rupture disc to open the displaced fluid bore for flow in the down-hole direction. A pickup force allows the releases of a dart to set the line hanger packer that is not shown and release the tops down cementing tool in a known manner. As a backup a ball can be cammed out of a hole with relative rotation of adjacent housing components after aligning an exit port for the ball with the picking up. The picking up also closes the crossover exit port to allow pressuring up on the dart to deliver the dart to the liner hanger packer.
In either case, rotation during cementing is enabled. Top down cementing is made possible by setting a cement packer and opening a cement crossover port below the set cement packer so that cement can be delivered in a down-hole direction and returns are blocked from the cement bore and come up and crossover an adjacent bore that has an initially closed upper end and a displaced fluid exit port above the set packer and below the closed upper end for the displaced fluid bore. The displaced fluid bore is then opened after cementing and lateral ports in both bores are isolated and the cement packer is unset while a ball or dart is released through the displaced fluid bore with the cement bore isolated to pressure from above. The liner hanger packer is set and the running tools are released and the top down cementing tool is pulled out of the hole.
The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below:
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A top down cementing tool operates with either mechanical manipulation or hydraulically. Rotation of the liner during cementing is enabled. A first bore is open for circulation during running in of the liner. In the hydraulic version, pressuring up on a dropped ball in the first bore opens cement packer setting ports and aligns crossover ports from the first bore to the annulus below the cementing packer and displaced fluid return ports to the annulus above the cementing packer. Pressuring up on a trailing wiper plug in the first bore opens the second bore so that pressuring on a seated ball in the second bore opens access to unsetting the cementing packer and launching the ball in the second bore for liner hanger setting and release of the running tool. The alternative embodiment gets the same result but with string manipulation for some of the realignments.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional application of published U.S. application Ser. No. 10/336,730, filed Jan. 6, 2003 now U.S. Pat. No. 6,669,139, which claims priority under 35 U.S.C. § 119 to French Patent Application 02 04334, filed on Apr. 8, 2002, the entire disclosure of both which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to aircraft with electric flight controls including a fuselage able to deform and vibrate longitudinally and laterally with the formation of vibration nodes and antinodes distributed along the longitudinal axis of the aircraft. It relates quite particularly to long-length airplanes which have high longitudinal flexibility. However, it advantageously applies equally well to airplanes of a shorter length and lower flexibility.
2. Discussion of the Background
It is known that an aircraft with electric flight controls has flight controls such as sticks, mini sticks, rudder bars, etc., which are equipped with electric transducers so that they generate electric flight control datums representative of the action that a pilot exerts on them. It also includes a flight control computer which, on the basis of the electric flight control datums generated by the flight controls and of flight control parameters originating, for example, from sensors, formulates electric commands that the flight control computer applies to actuators tasked with moving the control surfaces of the aircraft.
It is also known that aircraft with electric flight controls are provided with an inertial reference system (generally known as an IRS) including elements useful in navigation, such as the inertial unit, and elements useful in flight control, such as gyrometers and accelerometers. Finally, it is known that all these elements, whether they have to do with navigation or flight control, are grouped together in an IRS unit arranged at a given point on the aircraft. Of course, as a result, this IRS unit is subjected to the action of the deformations of the fuselage, which deformations occur mainly along the axes of pitch and yaw under the effect of the turning of the control surfaces or the effect of external disturbances.
Because of the high time constant attached to the elements useful in navigation, such deformations have only a small action thereon. By contrast, in order to get around the problems of interaction between the deformations of the fuselage and the elements useful in flight control, it is essential to have filtering means on the control surface control lines.
However, in the case of aircrafts with high longitudinal flexibility, the deformations become greater, which means that it is then necessary to perform extremely intense filtering of the control lines, and this introduces significant phase shifts thereinto and therefore detracts greatly from the performance of the control lines.
SUMMARY OF THE INVENTION
It is an object of the present invention to overcome this drawback.
To this end, according to the invention, an aircraft with electric flight controls, provided with control surfaces able to be moved by electrically operated actuators, includes controls and at least one flight control computer. The controls are actuated by a pilot and generate electric flight control datums which are sent to the flight control computer. The latter computer generates, on the basis of the electric flight control datums and flight control parameters, commands in roll, pitch and yaw, which are sent to the actuators to move the control surfaces. An inertial reference system includes elements useful in navigation and elements useful in flight control, the latter elements being either of the gyrometer type or the accelerometer type. The aircraft includes a fuselage able to deform and vibrate with the formation of vibration nodes and antinodes distributed along the longitudinal axis of the aircraft.
The inertial reference system has an exploded structure with the elements useful in flight control separated from the elements useful in navigation. The elements useful in flight control are distributed along the fuselage. Each element useful in flight control, of the gyrometer type, is arranged at a vibration node of the fuselage. Each element useful in flight control, of the accelerometer type, is arranged at a vibration antinode of the fuselage. The elements useful in flight control are connected to the flight control computer so that the measurement signals they deliver are used as flight control parameters.
Thus, the accelerometers allow the measurement of the accelerations of the aircraft including vibrational movements of the fuselage, while the gyrometers allow the measurement of the rotation rates without incorporating the structural modes of the fuselage thereinto. These accelerometer and gyrometer measurements are sent to the flight control computer which in consequence formulates commands for the control surfaces.
The flight control laws incorporated into this computer therefore do not need to filter the vibrational movements of the fuselage. This is because the structural modes measured by the accelerometers can be actively checked by the flight control laws while the gyrometers do not measure deformations of the fuselage. In the most frequent scenario, the aircraft fuselage deforms and vibrates in such a way as to have a vibration antinode at each of its ends, and a vibration node near its center of gravity.
In this case, the aircraft includes at least one front accelerometer arranged at the front part of the fuselage and delivering a vertical acceleration measurement and a lateral acceleration measurement. At least one rear accelerometer is arranged at the rear part of the fuselage and delivering a vertical acceleration measurement and a lateral acceleration measurement. At least one gyrometer is arranged near the center of gravity of the aircraft and delivering roll rate, pitch rate and yaw rate measurements.
It is then advantageous for the vertical acceleration measurements generated by the front accelerometer and by the rear accelerometer respectively and the pitch rate measurement generated by the gyrometer, to be used as flight control parameters to formulate the pitch commands. The lateral acceleration measurements generated by the front accelerometer and by the rear accelerometer respectively, and the roll rate and yaw rate measurements generated by the gyrometer, can be used as flight control parameters to formulate the roll commands. The lateral acceleration measurements generated by the front accelerometer and by the rear accelerometer respectively, and the roll rate and yaw rate measurements generated by the gyrometer, can be used as flight control parameters for formulating the yaw commands.
The aircraft can include means of filtering the acceleration measurements and the rate measurement or measurements to eliminate measurement noise therefrom and avoid spectrum folding. The aircraft can also include gain multipliers for weighting each of the filtered acceleration or rate measurements; phase control means for the filtered and weighted acceleration measurements; and summing means for summing the filtered, weighted and phase-controlled acceleration measurements, the filtered and weighted rate measurement or measurements and the corresponding electric flight control datum to formulate the corresponding command.
The aircraft may also, for formulating roll and yaw commands, include means of integrating the roll rate so as to create information about the roll angle, which information is sent to the summing means after it has been weighted by a gain multiplier.
Of course, in such an architecture, all the gains are optimized so as to satisfy the compromises between performance and stability. It is also found that the architecture according to the present invention makes it possible to dispense with low-frequency filters, even though the aircraft might be very flexible.
BRIEF DESCRIPTION OF THE DRAWINGS
The figures of the appended drawing will make it easier to understand how the invention may be embodied. In these figures, identical references denote similar elements.
FIG. 1 schematically and generally illustrates the electric flight control system according to the present invention, the one example of an airplane with high longitudinal flexibility.
FIG. 2 shows, in schematic perspective, a civil transport airplane, with the locations of its accelerometers and gyrometers.
FIG. 3 is the block diagram of the pitch control system of the airplane of FIG. 2 .
FIG. 4 is the block diagram of the roll and yaw control systems of the airplane of FIG. 2 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The airplane 1 with high flexibility along its longitudinal axis L—L, shown in FIG. 1 , can deform under the effect of the turning of its control surfaces or of external disturbances so that the main deformation of its fuselage 2 in the yaw and pitch axes is very significant at the front 3AV and rear 3AR ends of the fuselage 2 while the center 4 of this fuselage (at which the center of gravity of the airplane 1 is located) deforms little. In addition, the rotation rates associated with the deformations of the fuselage 2 are very small near the center 4 of the fuselage.
As illustrated schematically in FIG. 1 , the airplane 1 includes:
an inertial unit CI, intended for navigation and arranged at any customary and appropriate point on the fuselage 2 ;
at least one front accelerometer 5 arranged at the front end 3AV;
at least one rear accelerometer 6 arranged at the rear end 3AR; and
at least one gyrometer 7 near the center 4 of the airplane 1 .
Of course, although in FIG. 1 the accelerometers 5 and 6 and the gyrometer 7 are depicted on the outside of the airplane 1 to make the drawings clear, they are, in actual fact, housed inside the fuselage 2 as depicted schematically in FIG. 2 .
The front and rear accelerometers 5 and 6 make it possible to measure the accelerations of the airplane 1 , including the vibrational movements of the fuselage 2 , these accelerations being measured in the form of their lateral components (NYAV in the case of the front accelerometer 5 , and NYAR in the case of the rear accelerometer 6 ) and vertical components (NZAV in the case of the front accelerometer 5 , and NZAR in the case of the rear accelerometer 6 ). Moreover, the gyrometer 7 makes it possible to measure the rotation rates of the fuselage 2 near the center of gravity of the airplane 1 , excluding the contribution of the structural modes thereof. These rotation rates are broken down into their three components P (roll rate), Q (pitch rate) and R (yaw rate) near the center of gravity of the airplane 1 .
Moreover, the airplane 1 includes:
at least one stick 8 , for example of the mini stick type, intends to be actuated by a pilot (not depicted) and associated with a transducer 9 generating roll and pitch flight control datums representative of the movements of the stick 8 ;
at least one rudder bar 10 intended to be actuated by the pilot and associated with a transducer 11 generating yaw flight control datums representative of the movements of the rudder bar 10 ;
at least one flight control computer 12 which, in the usual way, receives:
via links 13 , the roll and pitch flight control datums generated by the controls 8 , 9 ;
via links 14 , the yaw flight control datums generated by the controls 10 , 11 ; and
via links 15 , flight control parameters originating from sensors, other computers, etc.
Some of the links 15 connect the accelerometers 5 and 6 and the gyrometer 7 to the flight control computer 12 so that the measurements NZAV, NZAR, NYAV, NYAR, P, Q and R form part of the flight control parameters sent to the computer 12 via the links 15 .
On the basis of the roll, pitch and yaw flight control datums and of the flight control parameters, the flight control computer 12 generates commands which are sent to a number of actuators 16 . 1 , 16 . 2 , . . . , 16 .i, . . . , 16 .n each of which moves a control surface 17 . 1 , 17 . 2 , . . . , 17 .i, . . . , 17 .n accordingly.
It can be seen that the structural vibration modes measured by the accelerometers 5 and 6 can thus be actively checked by the flight control laws embedded in the computer 12 , while the gyrometer 7 does not take fuselage deformation into consideration. There is therefore no need, using these flight control laws, to filter the vibrational movements of the fuselage 2 .
As can be seen in FIG. 2 , the accelerometers 5 and 6 are arranged respectively at locations 18 and 19 at the front end 3AV and at the rear end 3AR of the airplane 1 . Furthermore, the airplane includes:
an elevator 21 , articulated to the trailing edge of an adjustable horizontal plane 22 ;
ailerons 23 and spoilers 24 , articulated to the trailing edge of the wings 25 ; and
a rudder 26 articulated to the trailing edge of the vertical stabilizer 27 .
Of course, each of these control surfaces 21 to 24 and 26 corresponds to one of the control surfaces 17 .i (where i=l to n) in FIG. 1 .
FIG. 3 schematically depicts the part 12 A of the flight control computer 12 corresponding to pitch control in accordance with the present invention and intended to control the elevator 21 and the adjustable horizontal plane 22 . This control is effected through front and rear vertical acceleration measurements NZAV and NZAR and the measurement of the pitch rate Q near the center 4 , which are sent to it via the corresponding links 15 .
In this part 12 A of the flight control computer 12 , each measurement NZAV, NZAR and Q is filtered by respective filter means 28 , 29 and 30 , and weighted with a gain, by gain multipliers 31 , 32 and 33 respectively. Such filtering, the purpose of which is to avoid noise and spectrum folding, relates to the high frequencies in excess of 10 Hz. It is therefore not penalizing to the performance of the pitch control. In addition, phase controllers 34 and 35 receiving the weighted accelerometer measurements NZAV and NZAR are able actively to check the structural modes of the fuselage 2 . Such phase control corresponds to an adjustment of the pitch control law, the adjustment being pegged to the phase of the structural modes, so as to increase their damping. The signals leaving the phase controllers 34 and 35 and the gain multiplier 33 are summed in a summer 36 , making it possible at output therefrom to obtain a pitch command that is a function of the three measurements NZAV, NZAR and Q.
Furthermore, this part 12 A of the computer 12 additionally includes a processing device 37 and a gain multiplier 38 for the pitch flight control datum generated by a control 8 , 9 and sent to the device 37 via a link 13 .
This pitch flight control datum thus processed and weighted by the device 37 and the multiplier 38 sent to a summer 39 in which it is summed with the pitch command that appears at output from the summer 36 .
The composite pitch command appearing at the output of the summer 39 is sent to the actuators 16 .i of the elevator 21 and of the adjustable horizontal plane 22 to move these accordingly.
FIG. 4 schematically depicts the parts 12 B and 12 C of the flight control computer 12 correspondingly respectively to roll control by means of the ailerons 23 and the spoilers 24 and to yaw control by means of the rudder 26 . These two parts 12 B and 12 C of the computer 12 receive, via the corresponding links 15 , the lateral acceleration measurements NYAV and NYAR delivered by the accelerometers 5 and 6 , together with the roll rate P and yaw rate R which are measured by the gyrometer 7 .
In each of the parts of the computer 12 B and 12 C, each measurement NYAV, NYAR, P and R is filtered by high-frequency filtering means (frequency in excess of 10 Hz) 40 , 41 ; 42 , 43 ; 44 , 45 ; 46 , 47 , respectively, allowing the corresponding commands to get around problems of noise and spectrum folding without disadvantageous influence on the performance of the commands. In addition, the measurements are weighted using gains, by virtue of respective gain multipliers 48 , 49 ; 50 , 51 ; 52 , 53 ; 54 , 55 . Respective phase controllers 56 , 57 and 58 , 59 (analogous to the controllers 34 and 35 of the part 12 A of the computer 12 ) receive the weighted accelerometer measurements NYAV and NYAR so as to check actively the structural modes of the fuselage 2 . The signals leaving the controllers 56 and 58 and the gain multipliers 52 and 54 are sent to summers 60 . Likewise, the signals leaving the controllers 57 and 59 and the gain multipliers 53 and 55 are sent to a summer 61 .
In addition, in each part of the computer 12 B or 12 C, the filtered roll rate P appearing at the outputs of the filtering means 44 or 45 respectively is integrated by an integrator 62 or 63 then weighted by a gain multiplier 64 or 65 . Such integration actions make it possible to create information about the roll angle, which information is sent to the respective summer 60 or 61 .
Thus, at the outputs from the summers 60 and 61 there are obtained, respectively, a roll command and a yaw command each of which is a function of the four measurements NYAV, NYAR, P and R and of the roll angle information resulting from integration by the integrator 62 or 63 respectively.
The flight computer part 12 B additionally includes a processing part 62 and a gain multiplier 64 for the roll flight control datum generated by a flight control 8 , 9 and sent to the device 62 by a link 13 . This roll flight control datum thus processed and weighted by the device 62 and the gain multiplier 64 is sent to a summer 66 in which it is summed with the roll command appearing at the output of the summer 60 . The composite roll command appearing at the output of the summer 66 is sent to the actuators 16 .i of the ailerons 23 and of the spoilers 24 .
Likewise, the part of the computer 12 C additionally includes a processing device 63 and a gain multiplier 65 for the yaw flight control datum generated by a flight control 10 , 11 and sent to the device 63 by a link 14 . This yaw flight control datum thus processed and weighted by the device 63 and the gain multiplier 65 is sent to a summer 67 in which it is summed with the yaw command appearing at the output of the summer 61 . The composite yaw command appearing at the output of the summer 67 is sent to the actuators 16 .i of the rudder 26 .
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A method for controlling an aircraft includes the steps of receiving acceleration data related to an acceleration of a front portion of the aircraft, and receiving pitch, roll, and/or yaw rate data related to a rate of a center portion of the aircraft. The method also includes a step of generating a pitch, roll, and/or yaw command based on the acceleration data and on the rate data.
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BACKGROUND OF THE INVENTION
The invention relates to rotary drill bits for use in drilling or coring holes in subsurface formations, and of the kind comprising a bit body having a shank for connection to a drill string, a plurality of cutting elements mounted on the bit body, and a passage in the bit body for supplying drilling fluid to the surface of the bit body for cooling and/or cleaning the cutting elements, at least some of the cutting elements each comprising a preform cutting element having a superhard front cutting face.
The invention is particularly, but not exclusively, applicable to drill bits of the kind in which the cutting elements comprise preforms having a thin facing layer of polycrystalline diamond bonded to a backing layer of tungsten carbide. Such bits and cutting elements are well known and will not therefore be described in detail.
When drilling deep holes in subsurface formations, it often occurs that the drill bit passes through a comparatively soft formation and then strikes a significantly harder formation. Also there may be hard occlusions within a generally soft formation. When a bit using preform cutters meets such a hard formation the cutting elements may be subjected to very rapid wear or damage.
It has therefore been proposed to provide, on the rearward side of at least certain of the preform cutting elements, which may be regarded as primary cutting elements, secondary abrasion elements which are set slightly below (or inwardly of) the primary cutting profile defined by the primary cutting elements.
In this specification, the primary cutting profile is defined to mean a generally smooth notional surface which is swept out by the cutting edges of the primary cutting elements as the bit rotates without axial movement. The secondary profile is similarly defined as the notional surface swept out by the secondary elements.
With such an arrangement, during normal operation of the drill bit the major portion of the cutting or abrading action of the bit is performed by the preform primary cutting elements in the normal manner. However, should a primary cutting element wear rapidly or fracture, so as to be rendered ineffective, for example by striking a harder formation, the associated secondary abrasion element takes over the abrading action of the cutting element, thus permitting continued use of the drill bit. Provided the primary cutting element has not fractured or failed completely, it may resume some cutting or abrading action when the drill bit passes once more into softer formation.
The secondary elements may be formed in a variety of ways. For example, U.S. Pat. Nos. 4,718,505 and 4,889,017 describe a secondary abrasion element comprising a plurality of particles of superhard material, such as natural diamond, embedded in an elongate stud-like carrier element having one end wholly enclosed within a socket in the bit body which is spaced rearwardly from the respective primary cutting elements, and the other end protruding freely from the bit body transverse to the normal direction of rotation of the bit.
Hitherto, it has been the usual practice for all the secondary elements to be set slightly below, or inwardly of, the primary cutting profile by a substantially constant distance, measured perpendicular to the primary profile. However, it is believed that this may be disadvantageous, and may have the effect that secondary elements on some parts of the bit come into operation before secondary elements on other parts, even though they may be subjected to the same local conditions.
Because the drill bit is moving axially as drilling proceeds, the parameter which determines when a secondary element comes into operation, other things being equal, is its position, relative to the primary profile, measured in a direction parallel to the longitudinal axis of rotation of the drill bit (referred to herein, for convenience, as the "vertical" distance). However, the primary cutting profile of the drill bit is usually shaped to provide a "nose" portion which is generally convex, although not necessarily smoothly curved, when viewed in cross-section. The nose portion of the profile is that part thereof which is lowermost when drilling vertically. The nose portion may lie on the central longitudinal axis of the bit in the case where the primary profile is simply convex, or it may comprise an annular area spaced outwardly of said axis in the case where the central portion of the profile is concave, cone-shaped, or otherwise re-entrant.
Due to the generally convex shape of the nose portion, as viewed in cross-section, the vertical distance between each secondary element and the primary profile increases with distance from the nose portion of the profile if the secondary elements are spaced by a constant distance from the profile, measured perpendicularly from the profile.
This means that, when harder formation or occlusions are encountered when drilling, the backing-up or depth stop function is not shared equally between the secondary elements, but falls mainly on the secondary elements nearer the central axis of the bit, leading to excessive wear and/or failure of those elements.
The present invention therefore sets out to provide an improved form of drill bit in which this disadvantage may be alleviated or overcome.
SUMMARY OF THE INVENTION
According to the invention there is provided a rotary drill bit for use in drilling or coring holes in subsurface formations, comprising a bit body having a central longitudinal axis and a shank for connection to a drill string, a plurality of primary cutting elements mounted on the bit body and defining a primary cutting profile having a nose portion, a passage in the bit body for supplying drilling fluid to the surface of the bit body for cooling and/or cleaning the cutting elements, at least some of the primary cutting elements each comprising a preform cutting element having a superhard front cutting face, there being associated with at least certain of said primary cutting elements respective secondary elements spaced inwardly of said primary profile, the distance of said secondary elements from the primary profile, when measured in a direction perpendicular to said profile, being generally greater for secondary elements nearer the nose portion than it is for secondary elements further away from the nose portion.
It will be appreciated that, if the spacing between a secondary element and the profile defined by the primary cutters is increased, the time at which that secondary element comes into operation during use of the drill bit will be effectively delayed. By adjusting the distance by which each secondary element is spaced from the primary cutting profile in accordance with the invention, it is possible to ensure that secondary elements on different parts of the bit body come into operation at substantially the same time regardless of their location of the bit and even though their respective cutting elements may be subjected to different rates of wear.
The distance from the primary profile of secondary elements furthest from the nose portion may be substantially zero.
Preferably the secondary profile, defined by the secondary elements, is spaced inwardly of the primary profile by a distance, measured perpendicular to the primary profile, which decreases smoothly with distance from said nose portion of the drill bit.
Preferably also, the distance of at least the majority of said secondary elements from the primary profile is substantially constant, when measured in a direction parallel to the longitudinal axis of the drill bit. That is to say the distance between the profiles is substantially constant, when measured in a direction parallel to the longitudinal axis of the drill bit, over at least a major portion of the primary profile.
In one embodiment, each secondary element is spaced, rearwardly with respect to the normal direction of rotation of the bit, from a respective cutting element. Advantageously, each secondary element is located at substantially the same radial distance from the central longitudinal axis of the bit as the respective cutting element. It will be appreciated that, in this case, if the two profiles are uniformly vertically spaced then the vertical distance between each cutter and its associated abrasion element will also be uniform.
Conveniently, each preform primary cutting element comprises a thin facing layer of superhard material bonded to a less hard backing layer, and each cutting element may be mounted on a carrier received in a socket in the bit body.
Preferably each secondary element comprises a stud-like element protruding from the bit body. The stud-like element may be separately formed from the bit body and have one end received and retained within a socket in the bit body, the other end of the stud-like element protruding from the bit body. Alternatively the stud-like element may be integral with the bit body.
In either arrangement a single body of superhard material may be embedded in said projecting end of the stud-like secondary element. For example, the projecting end of the stud-like secondary element may be generally frusto-conical in shape, said single body of superhard material being embedded at the central extremity of said frusto-conical shape.
Alternatively a plurality of bodies of superhard material may be embedded in at least the projecting end of said stud-like element.
In another embodiment said stud-like secondary element may be formed from tungsten carbide.
The primary cutting elements and secondary elements may be located on the bit body in radially spaced groups, the distance between the primary profile and the secondary profile being substantially uniform within each group but decreasing from group to group as the distance of the group from the nose portion of the bit increases.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the end face of a rotary drill bit including primary cutting elements and secondary abrasion elements;
FIG. 2 is a diagrammatic section through one primary cutting element and its associated secondary abrasion element;
FIG. 3 is a diagrammatic half-section through a rotary drill bit according to the invention, showing both primary cutting elements and secondary abrasion elements; and
FIG. 4 is a similar view to FIG. 3 showing a further embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1: a rotary bit body has a leading end face 10 formed with a plurality of blades 12 upstanding from the surface of the bit body. Drilling fluid is supplied through a passage (not shown) within the bit body, and flows out through nozzles 14 located on the leading face 10 so as to cool and clean primary cutting elements 16 mounted side-by-side along each blade 12. Spaced rearwardly of the outermost cutting elements 16 on each blade are secondary abrasion elements 18. Although the drawing shows only two abrasion elements 18 mounted on each blade 12, any number of the primary cutting elements 16 may be provided with an associated abrasion element 18, and although each abrasion element 18 may lie at the same radial distance from the axis of rotation of the bit as its associated cutting element 16, this is not essential.
The secondary abrasion elements 18 shown in FIG. 1 each comprise a single body of superhard material, such as natural or synthetic diamond, mounted at the apex of a generally conical end face of a stud, for example of cemented tungsten carbide, received in a socket in the blade 12. However, other forms of secondary element may be employed. For example, the separate stud may be replaced by a projecting boss, formed integrally with the bit body and in the conical extremity of which the superhard element is embedded.
FIG. 2 shows in greater detail another suitable form of secondary abrasion element, which will be described below. Although the secondary elements specifically described are abrasion elements, the invention also includes arrangements where the secondary elements are cutting elements, for example are similar to the primary elements and comprise polycrystalline diamond preform cutting elements.
As previously mentioned, in an alternative embodiment the secondary elements may be in the form of tungsten carbide studs protruding from the bit body. The studs may be integral with the bit body, forming bosses on the surface thereof, or may comprise separately formed studs which are received and retained in sockets in the bit body.
Referring to FIG. 2, each primary cutting element 16 is a circular preform comprising a front thin hard facing layer 20 of polycrystalline diamond bonded to a thicker backing layer 22 of less hard material, such as tungsten carbide. The preform is bonded, in known manner, to an inclined surface on a generally cylindrical stud 24 which is received in a socket in the bit body 10. The stud 24 may be formed from cemented tungsten carbide. The bit body 10 may be machined from steel or may be moulded from matrix material by a powder metallurgy process, in known manner.
Each secondary abrasion element 18 also comprises a generally cylindrical stud 26 which is received in a socket in the bit body 10 spaced rearwardly of the stud 24. In this example the stud 26 is formed from cemented tungsten carbide impregnated with particles 28 of natural or synthetic diamond or other superhard material. The superhard material may be impregnated throughout the body of the stud 26, or may be embedded in only the outer surface portion thereof.
In the arrangement shown, the stud 26 of the abrasion element extends substantially at right angles to the surface of the formation 32, but operation in softer formations may be enhanced by inclining the axis of the stud 26 forwardly or by inclining the outer surface of the abrasion element away from the formation in the direction of rotation.
In order to improve the cooling of the cutting elements and abrasion elements, a channel for directing drilling fluid may be provided between the two rows of elements as indicated at 30 in FIG. 2.
Any known form of preform cutting element 16 having a superhard cutting face may be employed and the invention includes within its scope arrangements where the cutting element is mounted directly on the bit body, or on another form of support in the bit body, rather than on a cylindrical stud such as 24.
It will be seen that the primary cutting element 16 projects downwardly slightly further than the associated abrasion element 18, so that initially, before any significant wear of the cutting element has occurred, only the cutting element 16 engages the formation 32. The abrasion element 18 will only engage and abrade the formation 32 when the primary cutting element 16 has worn beyond a certain level, or has failed through fracture. The further the cutting element 16 projects downwardly below the abrasion element 18 the greater is the wear of the primary element which must occur before the abrasion element 18 begins to abrade the formation 32. It is therefore possible, by selectively varying the vertical distances between the primary cutting elements 16 and the abrasion elements 18, to ensure that each of the abrasion elements 18 comes into operation and begins to abrade the formation 32 at substantially the same point in time during operation of the drill bit, and FIGS. 3 and 4 show two particular arrangements of cutting elements and abrasion elements by which this result may be achieved, in accordance with the present invention.
FIG. 3 is a diagrammatic sectional representation of one half of a rotary drill bit having a generally cone-shaped central recess 34 and a gauge portion 36. The central longitudinal axis of rotation of the drill bit is shown by the dotted line 38. A row of primary cutting elements 16 and associated secondary abrasion elements 18 is shown extending from the central recess 34 to the gauge portion 36. Each abrasion element lies directly behind its respective cutting element, with respect to the normal direction of forward rotation of the drill bit.
FIGS. 3 and 4 are intended to show, in a single quasi-sectional view, the relative radial positions of a series of primary and secondary elements on the drill bit. Although all the elements of a given type (i.e. primary or secondary) may be arranged side-by-side along a single blade, as shown, they could equally well be spaced apart circumferentially as well as radially, on the bit body. FIGS. 3 and 4 should therefore be regarded as representing the radial positions in which a series of circumferentially spaced elements pass through a fixed transverse plane, once during each revolution of the bit. Whereas the bit shown in FIG. 1 only has abrasion elements trailing the outermost cutting elements, the bit represented by FIG. 3 has abrasion elements spanning virtually the entire bit face.
In practice also, the bit body will normally carry further cutting elements, not shown in FIGS. 3 and 4, the radial positions of which further elements overlap the radial positions of the elements shown, so that a substantially continuous surface profile is cut in the formation as the drill bit rotates.
The profiles defined by the primary cutting elements and the secondary abrasion elements are represented by dotted lines 40 and 42 respectively.
Due to the presence of the central cone-shaped recess 34 in the bit body, each of the primary profile 40 is generally convex as seen in section, so as to provide an annular nose portion 46 which is lowermost when the drill bit is drilling vertically downwards.
It will be seen that, in the arrangement of FIG. 3, the spacing between the profiles of the cutting and abrasion elements 40, 42, (measured perpendicularly to the primary profile 40) decreases continuously as the profiles extend away from the annular nose portion 46. The rate of decrease is such as to maintain a substantially uniform vertical distance (i.e. measured in a direction parallel to the axis 38) between the two profiles in the region between the nose portion 46 and the outermost cutting elements 43.
The spacing between the profiles 40, 42 decreases to zero in the region of the gauge portion 36. In the arrangement shown, the decrease in the spacing between the profiles is more rapid radially inwards of the nose portion, and becomes substantially zero at the location of the innermost element 41. In other embodiments of the invention, however, a fixed vertical spacing between the two profiles may be maintained also in the central recessed region 34.
In the variant of FIG. 4 the cutting elements 16 and associated abrasion elements 18 are arranged in radially spaced groups, as denoted by dotted separation lines 44. The spacing between the abrasion elements 18 and the primary profile 40 of the cutting element (measured perpendicular to the profile) is uniform within each group, but the spacing for successive groups decreases as the distance of the group from the nose portion 46 increases.
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A rotary drill bit for drilling holes in subsurface formations comprises a bit body having a shank for connection to a drill string, a plurality of preform primary cutting elements mounted on the bit body and defining a primary cutting profile having a downwardly convex nose portion. There are associated with at least certain of the primary cutting elements respective secondary elements which are spaced inwardly of the primary profile. The distance of the secondary elements from the primary profile, when measured in a direction perpendicular to said profile, is generally greater for secondary elements nearer the nose portion than it is for secondary elements further away from the nose portion, and is preferably such that the vertical distance of the secondary elements from the profile is substantially constant.
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CROSS-REFERENCE TO RELATED APPLICATION
Pursuant to 35 U.S.C. § 119(e), this application claims priority from Provisional Application No. 60/149,841, filed Aug. 19, 1999.
FIELD OF THE INVENTION
The invention relates generally to an improved gate device for preventing pedestrians and vehicular traffic from crossing railroad grades. Specifically, the present invention relates to gate devices that protect lowered railroad crossing gate arms from damage.
BACKGROUND OF THE INVENTION
Railroad crossing gate arms are lowered from a vertical position to a horizontal position to block traffic from crossing railroad tracks when a train is present. When lowered to their horizontal position, gate arms can suffer damage from passing vehicles, wind pressure and vandalism. Damage frequently results in broken gate arms that sever at their point of attachment to a crossing gate mechanism. Such damage risks exposing pedestrians and vehicular traffic to improperly guarded train crossings. To maintain safety and the integrity of grade crossing equipment, railroads expend substantial resources monitoring, repairing and replacing damaged crossing gates. Thus, in the first instance, it is advantageous to protect lowered gate arms from damage.
Various methods of protecting gate arms from damage were known to the prior art. Employing camblocks and ball bearings, U.S. Pat. No. 4,897,960 issued to Barvinek, et al., (hereinafter referred to as “Barvinek”) describes a mechanism designed to provide flexibility to lowered gate arms. Barvinek discloses a housing for pivotally mounting a support tube that swings a partially translucent, internally illuminated, impact-resistant gate arm away from an applied force. A camblock is mounted inside the housing, allowing the gate arm support tube, having a pair of ball bearings retained within, to rotate around a retaining pin that extends upwardly through the center of the camblock when force from a passing vehicle is applied. Downward force on the rotating gate arm support tube, applied by a coil spring mounted on the retaining pin, forces the arm to return to its original position parallel with the groove of the camblock when the force dissipates. However, Barvinek suffers from numerous problems. Relying on camblocks and ball bearings, Barvinek is expensive to manufacture, monitor and maintain. Moreover, Barvinek cannot return a displaced gate arm to a position parallel with the groove of the camblock if the gate mechanism rises while the gate is displaced. Finally, Barvinek provides no control over the rate of gate arm return and cannot prevent gate arm over travel into the flow of traffic.
Alternatively, U.S. Pat. No. 5,469,660, issued to Tamenne, (hereinafter referred to as “Tamenne”) employs a spring and hydraulic piston system. Tamenne discloses a pivot assembly allowing a lowered gate arm to rotate away from traffic when a passing vehicle applies pressure and then to return to its original position once pressure is removed. The pivot assembly is mounted on a counter-weighted gate arm mechanism and includes springs mounted on a shuttle post assembly to return the gate arm to a position perpendicular to the flow of traffic. The pivot assembly includes a hydraulic piston to buffer the rate of gate arm return and a weight channel to counterbalance the gate mechanism's main counterweight when the gate arm is rotated away from passing traffic. However, Tamenne also suffers from numerous problems. Tamenne's hydraulic piston system, like Barvinek's camblock and ball bearing system, is expensive to manufacture, monitor and maintain. Further, Tamenne's weight channel counterbalance places an imbalanced strain on the gate arm pivot assembly, risking damage to the gate arm mechanism. Tamenne also decreases safety at crossing grades when the gate arm is displaced, because the weight channel swings from a position generally parallel with the flow of traffic to a position generally perpendicular to the flow of traffic and through an area where pedestrians may be standing. Like Bamivek, Tamenne is incapable of returning a displaced gate arm back to its normal position if the gate mechanism rises while the gate is displaced.
Therefore, a need exists for a crossing gate mechanism that can rotate a crossing gate arm out of the way of a damaging force while safely and efficiently returning the gate to its normal position, that is capable of being adjusted for installation in conditions requiring varied gate arm lengths and flexibilities, that is capable of preventing excessive impact when the gate arm returns to its normal position, that prevents gate arm over travel upon return from a displaced position, that is capable of being adjusted for varying gate arm return force requirements, that is less expensive than existing spring-based crossing guard mechanisms, and that is not subject to the potential for deterioration of a cam-and-bearing based crossing gate mechanisms.
SUMMARY OF THE INVENTION
The present invention provides a crossing gate mechanism for use in a railroad crossing gate. In one embodiment, the crossing gate mechanism includes a gate arm adapter for receiving the gate arm and allowing rotation of the gate arm away from a normal operating position approximately perpendicular to a flow of traffic upon application of a displacement force. The gate arm adapter is capable of being pivotally mounted to a vertical support structure to allow the rotation of the gate arm. A return force mechanism coupled to the gate arm adapter provides for a return of a displaced gate arm adapter to the normal operating position upon removal of the displacement force. In the one embodiment, the crossing gate mechanism further includes a latch hook assembly that holds the gate arm adapter in its normal operating position in the absence of a displacement force. In another embodiment, the crossing gate mechanism further includes a drag brake that retards a rate of return of the gate arm adapter to the normal operating position from a displaced position upon removal of the displacement force.
In another embodiment, the crossing gate mechanism includes a crossing gate arm, the gate arm adapter, and a return force mechanism attachment point. The gate arm adapter receives the crossing gate arm and includes a hinge pin that allows rotation of the gate arm away from the normal operating position upon application of the displacement force. The return force mechanism attachment point is diametrically opposite the hinge pin from the gate arm, and the return force mechanism attachment point, the hinge pin, and the gate arm are disposed in a generally linear relationship.
In another embodiment, the crossing gate mechanism includes a latch hook assembly. The latch hook assembly includes a pivotally levered latch that selectively restrains the gate arm adapter in its normal operating position, and a latch hook pressure mechanism that applies a leveraging force to the pivotally mounted latch to produce a pivotally levered force of the latch. The latch hook assembly further includes a hook and drag surface that receives the pivotally levered force of the latch upon application of a displacement force to the crossing gate mechanism.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial top view of a crossing gate mechanism in accordance with a preferred embodiment of the present invention.
FIG. 2 is a partial side view of a crossing gate mechanism in accordance with a preferred embodiment of the present invention.
FIG. 3 is a partial front view of a crossing gate mechanism in accordance with a preferred embodiment of the present invention.
FIG. 4 is a partial front view of a latch hook assembly when operating as a braking mechanism in accordance with a preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention can be more fully understood with reference to FIGS. 1-4. FIGS. 1 and 2 are a partial top view and a partial side view, respectively, of a crossing gate mechanism 100 in accordance with a preferred embodiment of the present invention. Crossing gate mechanism 100 is pivotally mounted to a vertical support that also typically serves as a mounting support for railroad crossing warning lights and signage. Crossing gate mechanisms such as crossing gate mechanism 100 are typically attached to the vertical support by two crossing gate support arms 102 (one shown).
The crossing gate support arms 102 are attached to crossing gate mechanism 100 at opposite ends of the mechanism and raise and lower the crossing gate mechanism, thereby raising and lowering a crossing gate arm 202 attached to the crossing gate mechanism, in a vertical plane. Normally, crossing gate mechanism 100 is in an upright position, holding crossing gate arm 202 in a generally vertical orientation and allowing vehicles to proceed through a railroad crossing in the absence of train traffic. When actuated by an oncoming train, crossing gate mechanism 100 lowers crossing gate arm 202 , bringing crossing gate arm 202 into a position approximately parallel to the ground, in order to block vehicular traffic from proceeding through the crossing.
As shown in FIGS. 1 and 2, crossing gate mechanism 100 includes an upper cross channel 104 and a lower cross channel 204 . Each cross channel 104 , 204 is attached to each of the crossing gate support arms (e.g., crossing gate support arm 102 ), thereby pivotally affixing crossing gate mechanism 100 to the vertical support. Cross channels 104 , 204 are fitted with an upper hinge bracket 106 and a lower hinge bracket 206 that are generally centered between crossing gate support arms 102 . Crossing gate mechanism 100 further includes a gate arm adapter 108 that is pivotally mounted to each cross channel 104 , 204 via a hinge pin 110 . As shown in FIG. 2, hinge pin 110 is perpendicularly disposed between, and extends through an aperture in, each of cross channels 104 , 204 and hinge brackets 106 , 206 .
Crossing gate mechanism 100 further includes a return force mechanism that includes one or more, preferably three, spring assemblies 112 . Each spring assembly 112 is pivotally attached to the gate arm adapter 108 via a spring assembly hinge pin sleeve 115 and a spring assembly hinge pin 114 . Spring assembly hinge pin sleeves 115 fit over spring assembly hinge pin 114 acting as spacers to separate spring assembly adapters 117 . Using a fastener through a lower sleeve hole and the spring assembly hinge pin 114 , all parts stay in place within the top and bottom flanges of the gate arm adapter 108 . Spring assemblies 112 attach to the cross channels 104 , 204 via mounting flanges 116 using a similar pin and sleeve arrangement as just described. Spring assembly adapters 117 each provide an attachment point for the mounting of a spring assembly 112 , thereby providing for each spring assembly 112 to be pivotally attached to gate arm adapter 108 . In a preferred embodiment, gate arm adapter 108 is allowed to rotate about hinge pin 110 while the length of crossing gate arm 202 , hinge pin 110 and spring assembly hinge pin 114 and sleeve 115 maintain a generally linear relationship throughout rotation.
FIG. 1 further illustrates the typical operating positions of crossing gate mechanism 100 when it is in its lowered and approximately horizontal position relative to the ground. Reference position 118 indicates a normal operating position of lowered crossing gate mechanism 100 , wherein gate arm adapter 108 is generally perpendicular to the flow of vehicular traffic (as indicated by an approximately horizontal displacement force 120 ). Reference position 122 indicates a displaced position of lowered gate arm adapter 108 , achieved when displacement force 120 is applied to gate arm 202 , causing gate arm adapter 108 to rotate the gate arm 202 in an approximately horizontal plane about hinge pin 110 . By rotating crossing gate arm 202 , crossing gate mechanism 100 protects the gate arm 202 from potential damage due to the application of displacement force 120 . Preferably, the maximum angle of swing during displacement is approximately 68°; however, one of ordinary skill in the art realizes that other angles than 68° may be employed without departing from the spirit or scope of the present invention.
When displacement force 120 displaces gate arm adapter 108 from normal operating position 118 , each spring assembly 112 provides an approximately horizontal return force on gate arm adapter 108 at spring assembly hinge pin 114 . The return force causes gate arm adapter 108 and gate arm 202 to return from a displaced position 122 back into normal operating position 118 after displacement force 120 is removed. In a preferred embodiment, crossing gate mechanism 100 includes an interchangeable selection of spring assemblies 112 to provide more or less return force for returning longer or shorter gate arms 202 from the displaced position 122 to the normal operating position 118 . Spring assemblies 112 preferably provide adequate return force on gate arm adapter 108 so that gate arm 202 can be returned from a displaced position 122 to normal position 118 even if crossing gate mechanism 100 pivots in the vertical plane about its vertical support, as if to raise gate arm 202 while the gate arm is displaced.
In a preferred embodiment, crossing gate mechanism 100 further includes a shear pin 124 that is coupled between upper hinge bracket 106 , or alternatively lower hinge bracket 206 , and gate arm adapter 108 . Shearpin 124 provides crossing gate mechanism 100 with additional resistance to gate arm 108 rotation in high wind areas, yet will easily shear upon impact with displacement force 120 .
Referring now to FIGS. 1, 2 and 3 , wherein FIG. 3 is a partial front view of crossing gate mechanism 100 in accordance with a preferred embodiment of the present invention, crossing gate mechanism 100 further includes a latch hook assembly 126 . Latch hook assembly 126 latches gate arm adapter 108 in normal operating position 118 in the absence of displacement force 120 and serves to retard the rate of return of gate arm adapter 108 from displaced position 122 . Latch hook assembly 126 includes a latch hook 128 that is pivotally mounted to upper hinge bracket 106 , or alternatively to lower hinge bracket 206 , at a latch hinge 130 . Latch hook assembly 126 further includes a latch hook pressure mechanism 306 that applies a leveraging force to latch hook 128 . Latch hook pressure mechanism 306 includes a latch spring housing 132 attached to cross channel 104 , and/or cross channel 204 , and a latch spring 134 retained within a latch spring housing 132 by a latch spring retaining bolt 302 . Latch spring housing 132 includes one or more, preferably two, gate arm adapter stops 304 that serve as a positive return stop for the gate arm adapter 108 when the adapter is displaced by displacement force 120 , preventing gate arm 108 over travel beyond the normal operating position 118 upon return from displaced position 122 .
Latch hook assembly 126 , as shown in FIG. 3, latches gate arm adapter 108 in normal operating position 118 in the absence of displacement force 120 . Latch spring 134 transmits a leveraging force (in a direction indicated by arrow 307 ) to latch hook 128 via latch spring retaining bolt 302 . The leveraging force, transmitted by latch spring 134 through latch spring retaining bolt 302 to latch hook 128 , latches gate arm adapter 108 in normal operating position 118 . Preferably, latch hook 128 will remain latched to gate arm adapter 108 by the leveraged force of latch spring 134 through a minor rotation, such as 8° to 10°, out of the normal operating position 118 of gate arm 202 , allowing crossing gate mechanism to absorb a minor horizontal displacement force without unlatching. Those of ordinary skill in the art will realize that other angles than 8° to 10° may be employed without departing from the spirit or scope of the present invention.
FIG. 4 is a partial front view of latch hook assembly 126 when operating as a braking mechanism in accordance with a preferred embodiment of the present invention. Latch hook assembly 126 , as shown in FIG. 4, operates as a drag brake, retarding the rate of return of gate arm adapter 108 to normal operating position 118 when the adapter is in displaced position 122 . When displacement force 120 is applied to gate arm 108 causing gate arm adapter 108 to rotate out of its normal operating position 118 , gate arm adapter 108 applies an upward force on an end of latch hook 128 opposite the end disposed next to latch spring retaining bolt 302 . The upward force causes latch hook 128 to pivot about latch hinge 130 , depressing latch spring retaining bolt 302 and compressing latch spring 134 until latch hook 128 releases gate arm 108 . A brake plate 402 , fitted with a replaceable wear plate 404 that presents a hook and drag surface 406 to latch hook 128 , is mounted on gate arm adapter 108 to receive the pivotally levered force of latch hook 128 when gate arm adapter 108 is displaced from normal operating position 118 .
Pressure transmitted by latch spring 134 through latch hook 128 to gate arm adapter 108 via wear plate 404 causes a frictional contact between latch hook 128 and hook and drag surface 406 as the gate arm adapter 108 returns from displaced position 122 to normal operating position 118 and latch hook 128 correspondingly translates across hook and drag surface 406 . The frictional contact retards the return of gate arm adapter 108 . By retarding the rate of return of gate arm adapter 108 from displaced position 122 under power from spring assemblies 112 , latch hook assembly 126 operates as a drag brake and prevents excessive impact between gate arm adapter 108 and latch spring housing 132 at stops 304 . One of ordinary skill in the art realizes that a variety of latch springs 134 are available to provide more or less retarding force on gate arm adapter 108 and brake plate 402 through levered latch hook 128 . Upon return of gate arm assembly 108 to normal operating position 118 , latch hook assembly 126 returns to the position shown in FIG. 3 .
In sum, the present invention provides a crossing gate mechanism 100 that can rotate a crossing gate arm 202 out of the way of a damaging force while safely and efficiently returning the gate arm to its normal operating position 118 . Crossing gate mechanism 100 includes a latch hook assembly 126 that latches the gate arm in normal operating position 118 . Crossing gate mechanism 100 further includes a return force mechanism that includes multiple spring assemblies 112 that returns the gate arm 202 to the normal operating position after the gate arm has been displaced by a displacing force 120 . By varying the number of spring assemblies 112 used in the return force mechanism, or by using spring assemblies that apply a greater or lesser return force, crossing gate mechanism 100 is capable of being adjusted for installation in conditions requiring varied gate arm lengths and flexibilities and is capable of being adjusted for varying gate arm return force requirements. Latch hook assembly 126 also operates as a drag brake that is capable of preventing excessive impact when gate arm 202 returns to its normal operating position from a displaced position 122 .
Crossing gate mechanism 100 also includes return stops 304 that prevent gate arm over travel upon return from a displaced position 122 . By employing a drag brake, as opposed to a hydraulic piston of the prior art, to retard the rate of return of the gate arm 202 from a displaced position 122 , the present invention is less expensive than existing spring-based crossing guard mechanisms. Furthermore, by employing a return force mechanism that includes one or more spring assemblies applying an approximately horizontal return force when crossing gate mechanism 100 is in an approximately horizontal position, the potential for deterioration of a cam-and-bearing based crossing guard mechanism is eliminated.
While the present invention has been particularly shown and described with reference to particular 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 present invention.
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A railroad crossing gate mechanism is provided that includes a gate arm adapter which is pivotally mounted to allow a lowered gate arm to rotate away from a generally perpendicular force in a generally horizontal plane. The gate arm mechanism further includes multiple interchangeable spring assemblies that generate a return force to bring a displaced gate arm back to its normal operating position, and a latch hook assembly for selectively latching the gate arm in its normal position and controlling the rate of return of the gate arm from a displaced position through application of a pivotally leveraged force to a braking surface.
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FIELD AND BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to the field of medical devices and specifically to medical devices that are designed to monitor the respiratory characteristics of patient breathing, especially for those patients who are attached to mechanical ventilators.
[0002] Persons exhibiting acute or chronic respiratory failure, for example due to pulmonary infection or trauma, often require artificial ventilatory support and may therefore be connected, by means of flexible plastic ventilation tubing, to a mechanical ventilator. Correct functioning of such a ventilator entails continuous, accurate and reliable monitoring, by the ventilator, of airflow characteristics within the connecting plastic tubing. Such monitoring is often achieved by means of a gas-flow sensor interposed within the plastic ventilation tubing connecting the patient to the ventilator.
[0003] It will be well known to those familiar with the art that many mechanical ventilators utilize a flow sensor fashioned in the form of a bore of cylindrical tubing containing within it a strut, also known as an interfering body, in a manner which facilitates differential pressure measurements, at either end of the strut, that are proportional to the flow rate of the respiratory gases that pass through the sensor. Such a flow sensor is hereinafter referred to as a differential-pressure flow sensor, and is described in more detail below.
[0004] A differential-pressure flow sensor typically is comprised of a hollow cylindrical body having a bore, which can be connected between a ventilator and a patient. The differential-pressure flow sensor utilizes an aerodynamic strut that is disposed within the cylindrical bore of the sensor to create a drop in the pressure of the respiratory gases flowing through the sensor. The strut extends across the entire diameter of the bore of the flow sensor and bisects the circular bore of the sensor. The width of the strut is less than the diameter of the bore and the longitudinal length of the strut is less than the length of the bore. Further, the geometric cross section of the strut is symmetrical to the flow of respiratory gases flowing through the sensor in either direction, and has a generally elliptical cross section. The aerodynamic design of the strut preserves the laminar nature of airflow through the cylindrical bore as the air passes around the strut, such that airflow turbulence is minimal or absent within the flow sensor.
[0005] The aerodynamic strut has longitudinally exposed edge portions, such that when the differential-pressure flow sensor is interposed between a patient and a ventilator one edge portion is closer to the patient and the other edge portion is closer to the ventilator. Each of the edge portions of the aerodynamic strut contains a semicircular groove running the full height of the edge, that is, parallel to the short axis of the cylindrical body and extending from the inner surface of the cylindrical body on one side to the inner surface of the cylindrical body on the opposite side of the cylindrical body. One end of each groove is in continuity with a circular lumen within the wall of the cylindrical body. This circular lumen is thus located at the intersection between the inner surface of the cylindrical body and the edge portion of the aerodynamic strut. The circular lumen extends through the wall of the cylindrical body. On the outer surface of the cylindrical body this lumen receives tubing, which runs from the differential-pressure flow sensor to a pressure transducer, typically located within the mechanical ventilator.
[0006] The differential pressure measured by the flow sensor is due to the restriction to flow caused by the presence of the strut within the bore of the sensor. The drop in pressure is measured relatively between the groove in the first edge portion of the aerodynamic strut and the groove in the second edge portion of the aerodynamic strut. For example, when respiratory gases are flowing through the flow sensor from the first end to the second end, a high-pressure zone, also referred to as an area of static pressure, is created immediately adjacent to the first edge of the strut and a low-pressure zone, also referred to as an area of dynamic pressure, is created immediately adjacent to the second edge of the strut. The converse is true when the respiratory gases are flowing from the second end of the sensor toward the first end of the sensor. It should be emphasized that in terms of the functioning of the differential-pressure flow sensor, the actual point at which pressure is measured, using the venturi principle, is at the circular lumen on the inner surface of the cylindrical body, and that this pressure measurement reflects the pressure along the length of the groove in the edge portion of the aerodynamic strut.
[0007] The relative pressures of the respiratory gases flowing through the sensor are collected and conveyed to the pressure transducer through the circular lumens and the tubing connected thereto. The pressure transducer measures the received pressures, and the resultant data is then processed by a microprocessor so as to calculate the rate of gas flow through the differential-pressure flow sensor. This calculation is based on the principle that the drop in pressure across an obstruction in an airway is related to the square of the velocity of the fluids flowing through the airway. This principle is also true for the differential-pressure flow sensor. The general relationship between the flow velocity and the pressure drop as measured across the strut by the transducer is given by:
(flow velocity) 2 ΔP
[0008] where ΔP is the drop in pressure across the strut of the differential-pressure flow sensor. This relationship is unique for every unique flow sensor geometry and must be derived empirically. Accordingly, the plastic flow sensors that are used with a given ventilator and microprocessor are manufactured from the same molds and injection conditions so that the geometric variation between each flow sensor is negligible.
[0009] Determining the flow-to-pressure drop relationship is accomplished by forcing air through the differential-pressure flow sensor at predetermined flow rates and measuring the resulting changes in differential pressure across the strut through the lumens, so as to generate a set of data points. A high order linear equation is then fit to the data points. This equation closely follows the same general form as given above. Using this equation, a flow velocity for gases flowing through the differential-pressure flow sensor can be calculated from the differential pressures measured across the strut.
[0010] It is known, however, that standard differential-pressure flow sensors, as described above, suffer from several deficiencies. In particular, standard differential-pressure flow sensors have been found to function unreliably in the presence of high humidity within the respiratory gasses flowing through the sensor. Humidification of the inspired respiratory gasses is often achieved by flowing the respiratory gasses through a water humidifier before the gasses pass through the flow sensor and into the patient. This is desirable so as to prevent drying of the patient's respiratory tract mucousa during prolonged periods of mechanical ventilation. Humidity may also be introduced into the respiratory gasses in the form of aerosolized medications, which are frequently administered to mechanically ventilated patients. Even without the introduction of external humidity, the naturally expired respiratory gasses from a patient's lungs are of higher humidity than the inspired gasses, thus increasing the humidity of airflow through the differential-pressure flow sensor.
[0011] As the humidity of the respiratory gasses increases, water condensation may occur on the inner surface of the respiratory tubing and the differential-pressure flow sensor. When such condensation occurs in the circular lumen in the inner wall of the flow sensor, at which site pressure measurements are sensed, water blocks the lumen, thus distorting the pressure measurements recorded by the differential-pressure flow sensor, and invalidating the resultant flow data. Furthermore, water that has previously condensed elsewhere along the length of the flexible respiratory tubing may flow into the flow sensor due to movement of the tubing, and cover the pressure sensing lumen. The propensity for the pressure sensing lumen to become blocked by water is exacerbated by the narrow gauge of the lumen and its connected tubing, which causes liquid to enter the tubing by means of capillary action.
[0012] Several different solutions have been developed in an attempt to overcome this deficiency of differential-pressure flow sensors. One alternative has been to insert a heating electrode into the flow sensor so as to heat the inner surface of the sensor and thereby prevent water condensation. This technique requires the addition of electrical wiring and machinery to the flow sensor and ventilator, thus increasing the cost and mechanical complexity of the sensor. A second alternative has been to try ensure that the sensor remains oriented in space in such a way that the pressure-sensing lumen is on the superior aspect of the cylindrical body, rather than the dependent aspect where condensed water will accumulate due to gravity. This alternative has proven to be impractical, as movement of the patient or the flexible respiratory tubing inevitably results in movement of the flow sensor, and thus movement of the accumulated water within the sensor, causing blockage of the pressure-sensing lumen.
[0013] There is therefore a need for, and it would be highly advantageous to have, a differential-pressure flow sensor that prevents condensation of water vapor in the pressure-sensing lumens of the sensor, and that prevents blockage of the pressure-sensing lumens by condensed water which may flow into the sensor from the respiratory tubing. It would be desirable for such a sensor to achieve these aims without the addition of electrical components to the sensor.
SUMMARY OF THE INVENTION
[0014] The invention is a differential-pressure gas flow sensor, for use in mechanical ventilators, wherein the shape of the aerodynamic strut, or interfering body, prevents the lumens at which the differential pressures are sensed from becoming obstructed by condensed water. Three unique characteristics of the shape of the interfering body, which prevent water blockage of the pressure-sensing lumen from occurring and which are points of novelty of the current invention, are:
[0015] 1) For each edge portion, the pressure-sensing lumen is located—on the edge portion of the interfering body—distant from the inner surface, and closer to the central axis of symmetry, of the cylindrical body. Consequently, accumulation of condensed water in the dependant part of the sensor (along its inner surface) does not block the pressure-sensing lumen, which remains above the water level.
[0016] 2) The walls of the interfering body slope convergently from the elliptical base of the interfering body towards its center, rather than being essentially parallel to each other. This unique shape of the interfering body results in airflow patterns around the interfering body which generate turbulent boundary layer flow patterns near the base of the interfering body, distant from the pressure-sensing lumens. As turbulent boundary layers encourage water condensation and precipitation, these processes occur primarily at the base of the interfering body, rather than at the pressure-sensing lumens.
[0017] 3) Each edge portion of the interfering body slopes at an angle from the base of the interfering body to the location of the pressure-sensing lumen. Consequently, the leading edge of the interfering body (namely, the leading edge which faces towards the source of airflow) deflects the airflow along a flow vector oriented towards the pressure-sensing lumen on the opposite (trailing) edge portion in such a way as to flush condensed water out of the area of the pressure-sensing lumen.
[0018] In one acpect of the invention a differential-pressure flow sensor is provided, including a) an interfering body, having a first edge, disposed within a tube, the interfering body extending across the diameter of the tube, and b) a first pressure sensing port operative to sense an air pressure, the first port being disposed in the first edge not abutting the wall of the tube.
[0019] In another aspect of the present invention the first edge is inclined at an angle with respect to the axis of the interfering body extending across the diameter of the tube.
[0020] In another aspect of the present invention the angle is about 13 degrees.
[0021] In another aspect of the present invention the first edge is a leading edge with regard to a direction of airflow.
[0022] In another aspect of the present invention sides of the interfering body are convergent with each other along the diameter of the tube.
[0023] In another aspect of the present invention sides of the interfering body converge at an angle of about ten degrees with respect to the axis of the interfering body extending across the diameter of the tube.
[0024] In another aspect of the present invention sides of the interfering body are concave.
[0025] In another aspect of the present invention the pressure sensing port is disposed upon the first edge.
[0026] In another aspect of the present invention the pressure sensing port is recessed within the first edge.
[0027] In another aspect of the present invention the pressure sensing port has a diameter of about 1.54 millimeters.
[0028] In another aspect of the present invention the pressure sensing port is disposed in the first edge at about the midpoint of the first edge.
[0029] In another aspect of the present invention the tube is operative to hold a volume of liquid, and where the port is disposed in the first edge at a distance from a wall of the tube that is greater than a depth of the volume of liquid.
[0030] In another aspect of the present invention the interfering body is operative to disturb an airflow, the disturbed airflow including a boundary layer in proximity to the wall of the tube.
[0031] In another aspect of the present invention the boundary layer is turbulent.
[0032] In another aspect of the present invention the tube is Y-shaped.
[0033] In another aspect of the present invention the tube is respiratory tubing.
[0034] In another aspect of the present invention the tube is an endotracheal tube.
[0035] In another aspect of the present invention the interfering body has a second edge, and further includes c) a second pressure sensing port operative to sense an air pressure, the second port being disposed in the second edge not abutting the wall of the tube.
[0036] In another aspect of the present invention the second edge is a trailing edge with regard to a direction of airflow.
[0037] In another aspect of the present invention the first edge is operative to deflect an airflow along a vector directed towards the second pressure sensing port.
[0038] In another aspect of the present invention a method for measuring airflow is provided, including a) providing a differential-pressure flow sensor, the sensor including an edge and a pressure-sensing port, and b) deflecting an airflow from the edge along a vector directed towards the pressure-sensing port sufficient to remove liquid from the pressure-sensing port.
[0039] In another aspect of the present invention a method for measuring airflow through a tube is provided, including a) providing a differential-pressure flow sensor, the sensor including an interfering body, the interfering body being operative to disturb airflow through the tube, and b) disturbing the airflow through the tube around the interfering body, the disturbed airflow including a turbulent boundary layer in proximity to the wall of the tube.
[0040] In another aspect of the present invention a method for measuring airflow through a tube is provided, including a) providing a differential-pressure flow sensor, the sensor being operative to sense a pressure, and b) sensing a pressure at a location not abutting the wall of the tube.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:
[0042] [0042]FIG. 1 is an illustration of the overall structure of the flow sensor;
[0043] [0043]FIG. 2 is a longitudinal sectional side view of the flow sensor;
[0044] [0044]FIG. 3 is a longitudinal sectional top view of the flow sensor;
[0045] [0045]FIG. 4 is a short-axis view of the flow sensor;
[0046] [0046]FIG. 5 is an illustration of airflow patterns caused by the leading edge of the interfering body;
[0047] [0047]FIG. 6 is an illustration of a preferred embodiment of the flow sensor, and
[0048] [0048]FIG. 7 is an illustration of an alternative embodiment of the flow sensor.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0049] The present invention is a differential-pressure respiratory flow sensor for use in a mechanical ventilator.
[0050] The principles and operation of a differential-pressure respiratory flow sensor, according to the present invention, may be better understood with reference to the drawings and the accompanying description.
[0051] [0051]FIG. 1 shows the overall structure of the current invention. The figure can best be understood by simultaneously referring to FIGS. 2, 3, and 4 , which show side, top and short-axis views respectively of the device depicted in FIG. 1. A flow sensor 2 comprises a hollow cylindrical body 4 having a bore, and an interfering body 6 disposed within the bore of cylindrical body 4 . In the preferred embodiment, cylindrical body 4 is a segment of respiratory tubing, although it will be understood that any form of tubing may be used without departing from the spirit of the current invention. In terms of the current invention, the word “tube” is hereby defined as referring to a hollow conduit of any cross-sectional shape, including circular, elliptical and square.
[0052] Interfering body 6 extends across the entire diameter of the bore of cylindrical body 4 and bisects the circular bore of cylindrical body 4 . The width of interfering body 6 is less than the diameter of the bore of cylindrical body 4 and the longitudinal length of interfering body 6 is less than the length of the bore of cylindrical body 4 . As can be seen in FIG. 3, the geometric cross section of the strut is symmetrical to the flow of respiratory gases flowing through sensor 2 in either direction, and when represented in two dimensions approximates a rhombus or ellipse in shape, as will be described below. As such, two corners of interfering body 6 , at either end along its length, constitute longitudinally exposed edge portions 8 and 10 when represented in three dimensions. When airflow occurs through sensor 2 , edge portions 8 and 10 are thus leading and trailing edges, depending on the direction of airflow. In addition, the two corners of interfering body 6 at either end along its width constitute lateral edges 102 and 104 .
[0053] As can be seen in FIG. 2, interfering body 6 is wider superiorly, where it is in contact with the superior aspect of cylindrical body 4 , than what it is inferiorly, where it is in contact with the inferior aspect of cylindrical body 4 . Hereinafter, the wider, superior end of interfering body 6 will be referred to as the “base” of interfering body 6 , and the narrower, inferior end will be referred to as the “inferior insertion” of interfering body 6 .
[0054] A midpoint 32 bisects edge portion 8 into a first length 20 , running from the base of interfering body 6 to midpoint 32 , and a second length 36 , running from midpoint 32 to the inferior insertion of interfering body 6 . With regard to FIGS. 2 and 4, the term “horizontal” will refer to a plane that is parallel to the long axis of cylindrical body 4 and the term “vertical” will refer to a plane that is perpendicular to the long axis of cylindrical body 4 . In a preferred embodiment, midpoint 32 is generally located at the mid-point of the vertical length of edge portion 8 , that is, on the central axis of symmetry of cylindrical body 4 . In an alternative embodiment, midpoint 32 may be located asymmetrically along the length of edge portion 8 , that is, closer to one side of cylindrical body 4 than to the opposite side of cylindrical body 4 , at essentially any location on edge portion 8 . It is a particular feature of sensor 2 that first length 20 tapers at an incline from the inner surface of cylindrical body 4 towards midpoint 32 . In a preferred embodiment, first length 20 is inclined at an angle of 13 degrees from the vertical plane, although other degrees of angulation may be used without departing from the spirit of the current invention. Second length 36 , in contrast to first length 20 , is oriented vertically, and is recessed into the body of interfering body 6 relative to first length 20 . A semicircular groove 12 runs along the length of second length 36 . A horizontal shelf 40 , at the same vertical location on edge portion 8 as midpoint 32 , lies between the medial end of first length 20 and semicircular groove 12 . Horizontal shelf 40 contains a circular lumen 16 adjacent to semicircular groove 12 . In a preferred embodiment, the diameter of circular lumen 16 is 1.54 mm. A bore 24 runs from circular lumen 16 , within the body of interfering body 6 and in proximity to first length 20 , to the outer surface of cylindrical body 4 . At the outer surface of cylindrical body 4 , bore 24 receives tubing 28 . Tubing 28 runs from flow sensor 2 to a pressure transducer (not shown).
[0055] As can be seen in FIG. 4, that part of lateral edge 102 which extends from the base of interfering body 6 to the vertical level of circular lumen 16 (hereinafter referred to as the “upper part” of lateral edge 102 ) tapers at an incline. In a preferred 4 embodiment, this inclination is at an angle of 10 degrees from the vertical plane, although other degrees of angulation may be used without departing from the spirit of the current invention. In contrast, those parts of lateral edge 102 that extends from the vertical level of circular lumen 16 to the inferior insertion of interfering body 6 is oriented vertically. The dimensions and structure of lateral edge 104 are identical, in a mirror image, to those of lateral edge 102 .
[0056] Edge portion 10 and its surrounding surfaces are essentially a mirror image of edge portion 8 and its surrounding surfaces. Thus a midpoint 34 bisects edge portion 10 into a first length 22 and a second length 38 . First length 22 tapers at an incline (as described for edge portion 8 ) from the inner surface of cylindrical body 4 towards midpoint 34 . Second length 38 is oriented vertically, and is recessed into the body of interfering body 6 relative to first length 22 . A semicircular groove 14 runs along the length of second length 38 . A horizontal shelf 42 lies between the medial end of first length 22 and semicircular groove 14 . Horizontal shelf 42 contains a circular lumen 18 adjacent to semicircular groove 14 . A bore 26 runs from circular lumen 18 , within the body of interfering body 6 and in proximity to first length 22 , to the outer surface of cylindrical body 4 . At the outer surface of cylindrical body 4 , bore 26 receives tubing 30 . Tubing 30 runs from flow sensor 2 to a pressure transducer (not shown).
[0057] In a preferred embodiment of the current invention, the upper parts of lateral edges 102 and 104 (as depicted in FIG. 4) and first lengths 20 and 22 of edge portions 8 and 10 (as depicted in FIGS. 1 and 2) are straight. It is a particular feature of this embodiment, however, that in the upper part of interfering body 6 (that is, the part between the base of interfering body 6 and the vertical level of circular lumens 16 and 18 ), the external surfaces of interfering body 6 that lie between lateral edges 102 and 104 and edge portions 8 and 10 , are not straight, but are concave in shape. Thus, the horizontal, geometric cross section of interfering body 6 changes, depending on the vertical level at which the cross section is depicted. As can be seen in FIG. 3, the horizontal cross-section of interfering body 6 at its base is essentially elliptical (indicated as contour “A” in FIG. 3), whereas the horizontal cross-section of interfering body 6 at the vertical level of circular lumens 16 and 18 approximates a rhombus with rounded corners (indicated as contour “B” in FIG. 3). In a preferred embodiment, ellipse “A” has a circumference of 47.9 mm, a length of 17.7 mm, and a width of 6 mm, while contour “B” can be described as follows: the four corners of the rhombus-like shape are arcs of 3 mm diameter circles, and are connected to each other by tangents of those circles. The two circles whose arcs pass through edge portions 8 and 10 have a distance of 12 mm between their centers, and the two circles whose arcs pass through lateral edges 102 and 104 have a distance of 4 mm between their centers. The concave slopes of interfering body 6 have the effect of optimizing airflow patterns around interfering body 6 so as to prevent airflow turbulence from occurring in the flowing gas outside of the boundary layers. This configuration is particularly effective when cylindrical body 4 is fashioned in a Y-type configuration, as described below with regard to FIG. 6.
[0058] The upper part of interfering body 6 can thus be described as being a segment of an elliptically-based cone. This conical aspect of interfering body 6 , whereby the sides of interfering body 6 slope inwards from the base of interfering body 6 , is a novel feature of the current invention. When air flows through sensor 2 , the inward sloping of the walls of interfering body 6 generates a pattern of airflow which characteristically includes a turbulent boundary layer around the base of interfering body 6 . As will be well known to one familiar with the art, the interfering body of existing differential-pressure airflow sensors is designed so as to facilitate laminar airflow through the sensor, and specifically avoid turbulence. As such, the sides of the interfering body are essentially parallel to each other, a design feature that is aerodynamically advantageous for the purpose of minimizing turbulence both within and outside of the boundary layer of airflow. A point of novelty of the current invention lies in fashioning interfering body 6 with sloping (that is, non-parallel, or converging) sides so as to deliberately encourage turbulent airflow within sensor 2 . This design feature results in an area of turbulent airflow within the boundary layer at the base of interfering body 6 . As water precipitation is enhanced in turbulent (as opposed to laminar) boundary layers, droplets of water tend to precipitate at the base of interfering body 6 , rather than in pressure-sensing circular lumen 16 (which is distant from the base of interfering body 6 ), thus preventing blockage of circular lumen 16 by water droplets formed by condensation. Although in a preferred embodiment of the current invention the surfaces of interfering body 6 are concave, it is envisaged that the surfaces of interfering body 6 may be of any shape, including being flat, without departing from the spirit of the current invention.
[0059] Sensor 2 functions as a differential-pressure flow sensor in an identical manner to that described for standard differential-pressure flow sensors, whereby static and dynamic pressures are sensed at edge portions 8 and 10 at either end of interfering body 6 . It should be noted, however, that in terms of the functioning of the current invention, the actual points at which pressures are measured, using the venturi principle, are at circular lumens 16 and 18 , which are distant from the inner surface of cylindrical body 4 . Thus, accumulation of water on the inner surface of cylindrical body 4 does not cause obstruction of circular lumens 16 and 18 , even if movement of the patient or of the respiratory tubing causes the accumulated water to flow within cylindrical body 4 . It will be understood that circular lumens 16 and 18 on horizontal shelves 40 and 42 may be positioned at essentially any vertical displacement along edge portions 8 and 10 which would allow water to accumulate on the inner surface of cylindrical body 4 without obscuring circular lumens 16 and 18 , without departing from the spirit of the current invention.
[0060] [0060]FIG. 5 illustrates the pattern of airflow generated by edge portion 8 . The inclination of edge portion 8 generates an airflow vector (indicated by the arrows marked “C”) that is directed towards circular lumen 18 . This is in contrast to existing differential-pressure flow sensors, in which the leading edge portion is vertical and is not designed to specifically create a flow vector directed at the opposite pressure-sensing port. In the current invention, airflow along this vector has the effect of “flushing” water droplets out of circular lumen 18 . It will be understood that edge portions 8 and 10 may be fashioned in essentially any manner that produces an airflow vector directed towards circular lumens 18 and 16 respectively, without departing from the spirit of the current invention.
[0061] In a preferred embodiment, as shown in FIG. 6, cylindrical body 4 is fashioned in a Y-type configuration, such that interfering body 6 is positioned at the junction of the limbs of the Y, each of the two proximal limbs being functional to convey either inspiratory or expiratory airflow only, and the single distal limb being functional to convey bi-directional airflow to and from the patient interface. In an alternative embodiment, as shown in FIG. 1, cylindrical body 4 is executed in a straight cylinder configuration.
[0062] It should be noted that flow sensor 2 may be located at essentially any point along the path of airflow of a patient, whether such point be within the patient's respiratory tract, within the tubing of a ventilator connected to a patient, within a ventilator itself, or within essentially any device which receives either positive-pressure or negative-pressure airflow from a patient. In particular, as shown in FIG. 7, flow sensor 2 may be located at the distal end of an endotracheal tube 106 . Similarly, it is envisaged that flow sensor 2 may be located in a tracheostomy cannula, a suction catheter, a bronchoscope, or any other instrument that may be inserted into the respiratory tract.
[0063] [0063]FIG. 8 illustrates an alternative embodiment of interfering body 6 , wherein second length 36 is not recessed in relation to first length 20 . In this embodiment, circular lumen 16 opens into a recess 108 within second length 36 (rather than opening onto shelf 40 as in the preferred embodiment of interfering body 6 illustrated in FIGS. 1 through 6). As such, circular lumen 16 is located within interfering body 6 , rather than on edge portion 8 of interfering body 6 . Thus in both embodiments circular lumen 16 is located in edge portion 8 : either recessed within edge portion 8 or disposed upon edge portion 8 .
[0064] Although the current invention has been described as a ventilatory airflow sensor, it is envisaged that the current invention may be used in any application, both within and without the field of medicine, wherein the measurement of humid gas flow may be desirable.
[0065] There has therefore been described a differential-pressure flow sensor that, without the use of electrical components in the sensor, prevents condensation of water vapor in the pressure-sensing lumens of the sensor and prevents blockage of the pressure-sensing lumens by condensed water within the respiratory tubing.
[0066] While the present invention has been described with reference to one or more specific embodiments, the description is intended to be illustrative of the invention as a whole and is not to be construed as limiting the invention to the embodiments shown. It is appreciated that various modifications may occur to those skilled in the art that, while not specifically shown herein, are nevertheless within the true spirit and scope of the invention.
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A differential-pressure flow sensor for airflow measurement in the presence of water condensation, for use with mechanical ventilators. The pressure-sensing ports at either end of the interfering body are displaced from the inner surface of the surrounding tubing, so as to prevent obstruction of the pressure-sensing ports by free flowing condensed water. The leading edge of the interfering body is angulated so as to deflect airflow towards the pressure-sensing port on the trailing edge of the interfering body, thereby flushing water droplets away from the port. The sides of the interfering body are sloped so as to generate turbulent boundary layer airflow at areas distant from the pressure-sensing ports, thereby encouraging water condensation away from the ports.
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TECHNICAL FIELD
[0001] The invention relates to the field of touch screen navigation in general, and specifically to improving the ease of navigating, selecting and activating processes via a touch screen, especially as these features pertain to handheld devices such as cell phones, smart phones, personal digital assistants (“PDAs”), electronic book readers (“e-readers”), GPS devices, netbooks, and the like.
BACKGROUND OF THE INVENTION
[0002] Applications on Cell Phones or PDAs are typically launched through icons. A normal use case, from a user standpoint, is to click on an icon to start the desired application. On a screen not having touch sensitivity, access to additional functions is usually provided by positioning the cursor on an icon and clicking on the right mouse button. For example, on a Windows machine, clicking the right mouse button while the cursor is over the ‘My Computer’ icon displays the ‘Open, Explore, Search, Manage, Map Network Drive. . . ’ and additional menu items that can be accessed. On large touch screen systems, this approach works well. On Cell Phone or PDA touch screens, a mouse is not usually available and the touch access method is not practical because of the size of the fingers compared to the size of the cursor. Differentiating between two menu items using a finger is much more difficult than doing it using a mouse cursor.
SUMMARY OF THE INVENTION
[0003] A first embodiment is a method for activating objects displayed on a touch screen by using a finger of a user. The method includes the steps of displaying one or more objects on the touch screen, detecting an activation event of a specific one of the one or more objects caused by the user touching the specific object, and displaying a first peripheral zone around the specific object in response to detecting the activation event. The peripheral zone contains a plurality of regions each for allowing the activation of a function underlying the specific object by finger touch of the user.
[0004] A second embodiment is a computer-readable storage medium containing program code for controlling a handheld device to activate objects displayed on a touch screen by a finger of a user. The program code comprises code for displaying one or more objects on the touch screen, code for detecting an activation event of a specific one of the one or more objects caused by the user touching the specific object, and code for displaying a first peripheral zone around the specific object in response to the detection of the activation event. The peripheral zone contains a plurality of regions each for allowing the activation of a function underlying the specific object by finger touch of the user.
[0005] A third embodiment is a handheld device having a touch screen and containing program code for controlling the handheld device to activate objects displayed on the touch screen by a finger of a user. The program code comprises code for displaying one or more objects on the touch screen, code for detecting an activation event of a specific one of the one or more objects caused by the user touching the specific object, and code for displaying a first peripheral zone around the specific object in response to the detection of the activation event. The peripheral zone contains a plurality of regions each for allowing the activation of a function underlying the specific object by finger touch of the user.
[0006] The above as well as additional objects, features, and advantages of the present invention will become apparent in the following detailed written description.
BRIEF DESCRIPTION OF THE DRAWING
[0007] The novel features characteristic of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
[0008] FIG. 1 illustrates a typical touch screen handheld device with which the invention might be used;
[0009] FIGS. 2A , 2 B and 2 C show illustrative touch screen icon layouts using square or rounded-corner icons that might be used to practice the invention;
[0010] FIGS. 3A , 3 B and 3 C show an illustrative icon layout using circular icons; and
[0011] FIGS. 4 , 5 and 6 contain illustrative flowcharts of a software engine that might be used to control the display and activation of touch screen icons and menu functions in accordance with the invention.
DETAILED DESCRIPTION
[0012] As will be appreciated by one skilled in the art, the present invention may be embodied as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, the present invention may take the form of a computer program product on a computer-usable storage medium having computer-usable program code embodied in the medium.
[0013] Any suitable computer usable or computer readable medium may be utilized. The computer-usable or computer-readable medium may be, for example but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, or a magnetic storage device. Note that the computer-usable or computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted, or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory. In the context of this document, a computer-usable or computer-readable medium may be any medium that can contain or store the program for use by or in connection with the instruction execution system, apparatus, or device.
[0014] Computer program code for carrying out operations of the present invention may be written in an object oriented programming language such as Java, Smalltalk, “C++” or the like. However, the computer program code for carrying out operations of the present invention may also be written in conventional procedural programming languages, such as the “C” programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).
[0015] The present invention is described below with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
[0016] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function/act specified in the flowchart and/or block diagram block or blocks.
[0017] The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
[0018] With reference now to the figures and in particular with reference to FIG. 1 , there is depicted a typical handheld device containing a touch screen 10 , which in turn displays a multitude of icons, such as icon 14 that refers to an application SMS. The user of the handheld 10 typically taps the icon with a finger to activate the SMS application and typically to then display a new set of menu functions related to SMS.
[0019] The invention displays these additional functions in a new way to ease their selection or activation of the additional underlying functions with a finger. The terms “select” and “activate” and their variations are used interchangeably through depending on context. Instead of listing functions in a popup window with each function listed as a menu item, the invention displays them in a form that is better aligned in terms of look and feel with what is already displayed on the screen. Most icons are represented as circles or rounded squares, although many other icon shapes might be used. The invention adds a peripheral zone in which additional underlying functions are depicted. The icon with the peripheral zone provides a natural path for a user to navigate by sliding and tapping within the peripheral zone to activate underlying functions. Using an approach where the additional functions are displayed around the icon makes selection and activation much easier than using a traditional popup listing approach or cascading rectangular menus.
[0020] FIG. 2A shows another view of what corresponds to a touch screen 12 in FIG. 1 , without a containing handheld for simplicity. This particular screen shows a three by three matrix of application icons 20 for applications APP 1 through APP 9 . In one embodiment illustrated by FIG. 2B , when a user activates an icon for APP 7 , for example, by single or double tapping of the APP 7 icon with a finger, the icon with peripheral zone fills essentially the full extent of the touch screen and includes the peripheral zone shown at 22 . As briefly described above, the peripheral zone contains a number of additional underlying functions of APP 7 , such as FILE 24 and HELP 26 . The peripheral zone 22 provides an easy and natural way for a user to navigate with a finger the underlying functions of an APP icon and to activate a desired function. If a user changes his or her mind after selecting an APP icon, the user can easily return to the original screen by tapping the APP icon 28 in the middle of the icon. Of course, the peripheral zone need not totally surround a selected icon or object in all cases if not needed to adequately display underlying functions large enough to aid user selection and activation.
[0021] FIG. 2C illustrates a second embodiment in which a selected icon with peripheral zone consumes less that an entire touch screen. A choice of FIG. 2B or 2 C might depend on the number of underlying functions 29 in the peripheral zone that are associated with an APP icon, for example.
[0022] FIGS. 3A , 3 B and 3 C in the aggregate are illustrations of the concepts already discussed, but using circular icons rather than square icons. FIG. 3A shows an initial touch screen in which an icon has not been selected. FIG. 3B illustrates a selected circular icon in much the same way a square icon is selected as in FIG. 2C . This example of a selected circular icon still contains a peripheral zone 302 for displaying underlying functions.
[0023] FIG. 3C simply provides a larger view of a peripheral zone around a selected circular icon for clarity.
[0024] It is not intended to limit the invention to embodiments containing square or circular icons Almost every conceivable two-dimensional shape has the potential to be enhanced with a peripheral zone suitable for finger navigation; it is intended that the invention encompass such embodiments.
[0025] FIGS. 4 through 6 contain illustrative flowcharts that might be used to implement the invention. FIG. 4 illustrates the main flowchart in which a touch screen event message detected by an operating system of a handheld device is sent to a process associated with an active screen or window. This message receiving process of FIG. 4 first determines at step 402 the type of detected screen event that has been detected. An annotation to the right of step 402 lists a number screen events that are typically associated with a handheld device. Step 404 determines the screen position at which the event took place. If that position is not within an icon, step 408 transfers to a screen update process shown in FIG. 6 to process the event. If the event position is inside an icon, step 406 moves on to step 407 where the event type is used to determine if the event corresponds to a predefined configuration setup file. If the event does not correspond to a configuration setup file, the event is ignored by discarding the message at step 410 . Otherwise, step 412 fetches the matching configuration setup file and step 414 determines from the file if the screen event calls for an icon expansion in accordance with the invention. If icon expansion is not specified by the configuration setup file, the screen event is processed in a standard manner at step 416 . If icon expansion is required, step 418 places a call to an icon expansion subroutine illustrated in FIG. 5 .
[0026] With reference now to FIG. 5 , step 502 determines, or is given, the screen position of the icon that has been activated. Step 504 determines from the configuration setup file if the selected icon requires additional space to display underlying functions than the usual expansion algorithm. If so, step 506 computes a screen position for the selected icon. In any event, step 508 next displays the selected icon on the screen. FIG. 5B illustrates the screen as it might appear prior to selection and FIG. 5C illustrates the screen as it might appear after selection. The peripheral zone for underlying functions is not yet created. Step 510 gets additional information from the configuration setup file and step 512 determines if the underlying functions to be displayed in the peripheral zone requires additional layers of a peripheral zone. If an addition peripheral zone layer is not needed, step 514 creates the peripheral zone and displays the underlying functions. The screen then might appear as shown in FIG. 5D . If an additional layer is needed, step 516 computes its parameters and passes the information on to step 514 for creation. An example of an addition layer is shown at 518 of FIG. 5E . The process in FIG. 6A is then called at step 518 to update the screen information.
[0027] FIG. 6 illustrates a process that might be used to process screen events, including screen taps and screen navigation using fingers. Step 602 loops until a screen event message is received from an operating system. When an event message arrives, step 604 determines if the event represents a user navigating the screen by crossing a peripheral zone boundary by dragging a finger. If the answer is yes, then step 610 is entered where all peripheral zone functions are dimmed and then the function entered is high-lighted. This represents a typical function selection. FIG. 6B shows an illustration of a high-lighted function. If the event is not a peripheral zone boundary crossing at 604 , then 606 looks for a finger tap of the screen. If that is the case, and the tap is in an icon or function region, then this action might also represent a screen selection and step 610 is performed to high-light the peripheral zone function. If the event is a double-tap at step 612 and the double-tap is in an icon or function region at step 616 , then step 620 is performed to determine if the event is defined in the setup configuration file. Assuming that the event is defined, then step 622 activates the function that is defined in the configuration setup file. For all other screen event situations that might occur in this illustrative embodiment, the event is ignored. Obviously, many other screen events can be defined and processed in a similar manner as described.
[0028] It will be appreciated that the computer illustrated in FIG. 6 is merely illustrative, and is not meant to be limiting in terms of the type of system which may provide a suitable operating environment for practicing the present invention. While the computer system described in FIG. 6 is capable of executing the processes described herein, this computer system is simply one example of a computer system. Many systems are capable of performing the processes of the invention.
[0029] It should be clear that there are many ways that skilled artisans might use to accomplish the essential steps to implement an overall network solution, other that the specific steps and data structures described herein.
[0030] The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or actions, or combinations of special purpose hardware and computer instructions.
[0031] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
[0032] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.
[0033] Having thus described the invention of the present application in detail and by reference to preferred embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims.
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A method for activating objects displayed on a touch screen by using a finger of a user. The method includes the steps of displaying one or more objects on the touch screen, detecting an activation event of a specific one of the one or more objects caused by the user touching the specific object, and displaying a first peripheral zone around the specific object. The peripheral zone contains a plurality of regions each for allowing the selection or activation of a function underlying the specific object by finger touch of the user.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. patent application Ser. No. 10/397,703, filed Mar. 26, 2003, entitled “Interlocking modular tubular pallet” and U.S. Provisional Patent Application No. 60/366,033, filed Mar. 28, 2002, entitled “Interlocking modular polymer tubular design”.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to support structures, such as decking produced from plastic lumber materials, or pallets, for instance pallets on which articles are stacked or assembled to enable handling and shipment of articles. More specifically, the present invention relates to support structures that can be easily assembled in modular fashion in several configurations to provide continuous top and bottom surfaces, and at a minimal expense, and that can be easily assembled, disassembled and reassembled as needed for maintenance.
[0004] 2. Description of Related Art
[0005] Historically, pallets have been constructed with wood materials, having a plurality of parallel stringers on which are nailed or otherwise secured one or more structural members defining a platform. Pallets and decking have also been constructed of extruded or formed metal such as steel or aluminum, and also been molded or extruded plastic materials, including virgin plastic material or plastic material that has been recycled or reclaimed from waste. The materials used in said pallets and said decking are typically connected using mechanical fasteners or bonding agents.
[0006] Support structures of this type that are constructed of plastic have unique problems. For decking applications, the existing solid plastic lumber is heavier than the conventional wood deck and requires nails, fasteners, or adhesives to hold it together. Most pallet designs do not have interlocking sections and as such require fasteners.
[0007] Current designs for pallets utilizes fasteners to build structure into the pallet. The U.S. Air Force uses a balsa-wood pallet with aluminum skin to transport cargo in the cargo planes. The aluminum skin is attached to the balsa wood core material with adhesives and rivets. This design causes the pallet to be heavy and also requires the pallet to be repaired at the manufacturing facility in Minnesota. There is a need, then, for a pallet that is lighter, less expensive, and easier to repair than the current balsa wood pallet.
[0008] For wood decking applications, the wood and most plastic lumber materials are solid and are attached with nails into cross beams. Bending stresses in such a decking application occur on the top and bottom surfaces, but the solid material is used is very heavy.
[0009] Prior patents in the area of pallets and decking offer sections that do not interlock simply, but rather require fasteners or other connecting structures or devices. In such prior designs it is difficult to create and maintain a continuous surface across the top or bottom of the structure, as the structural elements used in such pallets or decking are connected with mechanical fasteners or bonding agents.
[0010] Prior art structures include U.S. Pat. No. 5,921,189, to Estepp, for a pallet made from a rectangular tubular elements of open ended plastic material in adjacent parallel contact, which and are fastened at outer sidewalls and at the ends by a fastening device.
[0011] U.S. Pat. No. 5,809,902, to Zetterberg, describes a pallet comprised of a solid deck comprised of rail elements that are attached together with at least two elongated, angularly folded fixing members that attach with insertable grooves made in the boards transverse to their longitudinal direction. The fixing member is made of metal as an angle piece with flanges. The grooves and fixing member engage on top surface and on perpendicular side face. The grooves are cut into deck material perpendicular to longitudinal direction
[0012] In Zetterberg the fasteners are required to secure the separate sections. The separate sections are connected with a modified angle iron that engages only at the ends of the rail elements. The middle sections of adjacent rails are not connected or secured to one another for support.
[0013] In some prior devices the side walls and not the top and bottom walls have an interlocking structure. A side-wall connecting pallet requires fasteners and/or adhesives to hold the structure together. The side-connecting plane results in a shearing plane being formed when weight is added to the top surface. The weight in loaded on the top surface, which is perpendicular to the side-interlocking surface. This is the cause of the shearing plane. The shearing plane is on the side walls and will result in the side walls separating as the weight on the top surface causes the pallet to bend. Thus the side walls still must be attached via mechanical fasteners and/or bonding agents. Current designs for pallets and decks utilize adhesives or fasteners to build structure.
[0014] No pallet or decking of the prior art provides sections that interlock and form a continuous surface on top or bottom. Thus there remains a need for a modular support structure that does not require special fasteners or bonding agents.
SUMMARY OF THE INVENTION
[0015] The present invention provides a tubular structure with a snap fit of interlocking sections that form a surface in the same plane as the weight on the top surface that would further engage the interlock connection With the invention, there is provided a modular pallet that can be easily disassembled and reassembled to connect other tubular sections, if a repair is required. It provides a pallet or decking product that is lighter, less expensive, and easier to install than current solid plastic lumber, and lighter, less expensive, and similar in cost to wood products.
[0016] The interlocking structure uses a modular structure with overlapping annular, or tubular, sections. Thus, there is provided a modular section for forming a support structure, being elongated and having a generally annular, or open, cross-sectional configuration with spaced upper and lower surfaces and spaced side walls, the upper and lower surfaces and side walls forming upper and lower edges, respectively, at the interfaces, wherein the upper and lower surfaces each comprise an extension at the respective upper and lower edges, the extensions having a flange formed at the ends thereof, and where the upper and lower surfaces each have a groove formed therein.
[0017] When two adjacent sections are aligned along respective side walls the flange of an upper surface extension fits the groove in the upper surface of its adjacent section and the flange of a lower surface extension occupies the groove in the lower surface of a neighboring section, thereby forming an interlocking fit of the adjacent sections. Preferably, the upper and lower surfaces of each adjacent modular section are disposed in substantially parallel relation with each other, and the side walls are disposed in substantially parallel relation with each other, and substantially perpendicular to the upper surface and the lower surface wall. In this way the upper surfaces of adjacent interlocking sections form a continuous planar surface for the support structure, as will the lower surfaces.
[0018] The modular sections may comprise at least one intermediate wall disposed between the side walls.
[0019] The modular sections are preferably integrally constructed, such as when formed by an extrusion process, though it may be formed by injection molding. A preferred such section is formed of polypropylene, and may have a recycled plastic content.
[0020] The groove in the upper surface of each modular section extends the length of respective upper and lower surfaces, and is formed in a portion of the upper and lower surfaces removed from the edges formed with the side walls.
[0021] The plurality of modular sections can be selected to form a flat surface, such as a pallet or deck, or may be configured to form a more complex article such as a a piece of furniture, a bench, a table or a chair.
[0022] A method for manufacture of a tubular pallet is also provided, comprising forming a plurality of modular sections each having a generally open cross-sectional configuration with spaced upper and lower surfaces and spaced side walls, the upper and lower surfaces and side walls forming upper and lower edges, respectively, at the interfaces, where the upper and lower surfaces each comprise an extension at at least one edge, the extension having a flange formed at the ends thereof, and where the upper and lower surfaces each have a groove formed therein; and establishing interlocking assembly of the interlocking sections for securing top and bottom walls of the plurality of pallet sections in interlocked assembly.
[0023] A tubular pallet is also provided comprising a plurality of elongated plastic modular sections having protruding flanges on the top surface and bottom surfaces of one side arranged to interlock with grooves formed in the top surface and bottom surface of the opposite side of an adjacent section. The flanges extends along the length of the tubular section and the grooves are formed such that a flange of one section is insertable into the corresponding groove formed in the adjacent section to secure one the adjacent sections. Each of the flanges has a depth and a width that substantially corresponds to a depth and width of the corresponding groove, though the groove may be wider that the width of the flange to allow for expansion.
[0024] In a preferred embodiment the flanges reversibly are removable from the grooves to allow easy disassembling of the pallet.
[0025] These and other features and advantages of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of the devices and methods according to this invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Various exemplary embodiments of this invention will be described in detail, with reference to the following figures, wherein:
[0027] FIG. 1 is an isometric illustration of an assembled structure with six modular sections ( 1 , 2 , 3 , 4 , 5 and 6 ), end pieces, middle connecting pieces, and cross piece that is constructed in accordance with principles of the present invention;
[0028] FIG. 2 is a fragmentary cross sectional view of the pallet construction showing an extruded single tube with three open channels and showing the interlocking tubular section;
[0029] FIG. 3 is a fragmentary isometric illustration similar to that of FIG. 2 and showing an extruded single tube with three open channels;
[0030] FIG. 4 is a fragmentary sectional view taken along section A-A as depicted in FIG. 1 and showing the interlocking features of the sections and the use of interconnecting cross piece;
[0031] FIG. 5 is a fragmentary sectional view taken along section B-B as depicted in FIG. 1 and showing the interlocking tubular sections;
[0032] FIG. 6 shows a middle connector piece for an assembled pallet, for connecting the open longitudinal ends of tubular sections;
[0033] FIG. 7 shows an end piece used for closing open longitudinal ends of outside tubular sections of a pallet structure.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0034] So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the preferred embodiment thereof which is illustrated in the appended drawings, which drawings are incorporated as a part hereof.
[0035] It is to be noted however, that the appended drawings illustrate only a typical embodiment of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
[0036] Thus, as will be understood more clearly from the embodiment of the support structure, in accordance with the invention, and illustrated in FIG. 1 , the support structure comprises tubular section members that interlock along the edges, as well as finish pieces that connect with the ends of the tubular sections. By “tubular” is meant that the section has an open, or annular, structure in cross section.
[0037] The support structure provides a continuous surfaces, top and bottom, without gaps, with large open or air spaces inside the structure based upon the annular profile section. Also, the support structure is made of sections that are interlocking and overlapping and snap together without fastening devices. A support structure, such as a pallet, produced from the tubular sections is lighter, less expensive, and easier to repair than current pallets made from balsa wood and aluminum skins.
[0038] Referring again to FIG. 1 , a support structure in the form of a pallet in accordance with the principles of the present invention and representing the preferred embodiment is illustrated generally as 100 . As seen in FIG. 1 , the pallet 100 is formed of sections connected without fasteners, but which interlock along the top and bottom surfaces. It is not necessary to form such a structure that one provide fasteners at the weaker side walls or along the outermost perimeter.
[0039] In FIG. 1 the pallet is shown composed of six subassembly sections, or sections 1 , 2 , 3 , 4 , 5 , and 6 , which are interconnected and which define a pallet structure of integral construction. The interlocking structure is built based upon a modular structure with each subassembly section further comprising overlapping tubular sections. For each tubular section a protruding flange is interlocked into a corresponding groove in an adjacent section. The tubular sections are connected together in this fashion until the desired pallet section is created.
[0040] Looking more particularly at pallet sections, FIGS. 2 and 3 , they have top 20 and bottom 30 surfaces. The interlocking and overlapping sections provide a continuous surface.
[0041] The interlocking flange design allows for structural integrity, smooth rolling surface on top and bottom. At least two tubular elements are located next to one another with collinear edges and are oriented in the same direction to support loads on top and bottom surfaces and resist bending. Each tubular section of subassembly sections 1 , 2 , 3 4 , 5 and 6 , has a planar upper wall 10 defining an upwardly facing planar surface 20 and with a planar lower wall 12 defining a downwardly planar surface 30 is substantially coplanar with the upper wall of the neighboring tubular section with the same geometry and planar upper wall 14 defining an upwardly facing planar surface 20 and with a planar lower wall 16 defining a downwardly planar surface 30 .
[0042] The edge of the top surface 10 of one tubular section has a flange 11 that protrudes from it and is of such a design that it fits in a corresponding groove 15 of an adjacent tubular section so as to provide a flat connected surface. The top walls 20 and 30 define flange and tab interlocking connectors for securing the pallet sections in immovable assembly. The protruding flanges 11 and 13 are on the top and bottom walls and on the right side with corresponding grooves 15 and 17 on the top and bottom walls and on the left side of the tubular section. The flange can as well be on the left side top and bottom walls with the corresponding groove on the right side top and bottom walls. Some tubular sections can have flanges on both top and bottom walls for the left and right sides. Some tubular sections can have grooves on both top and bottom walls for the left and right sides. Any combination of the flange and groove as fore mentioned to provide interlocking modular sections.
Section 1 in FIG. 1 has a configuration with the flanges on the right side of the section and with grooves on the left side of the section. Section 4 in FIG. 1 has flanges on the left side of the section and grooves on the right side of the section.
[0044] Numerous suitable methods are know for manufacturing the tubular sections having the open or annular characteristic. Looking to FIG. 2 , it is seen that each section has a generally open cross-sectional configuration, preferably composed of plastic material and having spaced upper and lower walls and spaced side walls, with the upper and lower walls of each tubular interlocking sections forming top and bottom surfaces defining the flange of one section. The top and bottom surfaces also comprise a groove configured so that the flanges of the neighboring section have a depth and a width that substantially corresponds to a depth and width of the corresponding groove of an adjacent section, so that the protruding flanges are insertable into the corresponding groove formed along the adjacent section. When so disposed next to one another with collinear edges the sections are oriented in the same direction to support loads on top and bottom surfaces that resist bending. Further, the surface between the groove and the edge may taper slightly to allow an easier fit. It is a simple matter to establish interlocking assembly of the sections for securing top and bottom walls of said plurality of pallet sections in interlocked assembly. The flanges may form angles relative to the top horizontal surface, either at right angles or less angled to accommodate a taper. The right angle or tapered angle need only be sufficient to interlock in the groove in an adjoining tubular section.
[0045] The grooves may be wider that the width of the flange to account for expansion and contraction of plastic sections during weathering effects of hot and cold ambient temperatures.
[0046] Thus, it is seen that the individual sections have a shape that may be extruded with the interlocking features molded in the tubular structure. More particularly, the annular sections, FIGS. 2 and 3 , can be made from processing methods, such as extrusion, stamping, machining, welding, etc. The annular sections, FIGS. 2 and 3 , can be made from conventional plastic and polymer processing methods, such as extrusion, injection molding, reaction injection molding, resin transfer molding, compression molding, pultrusion, hand lay-up methods, and polymer foaming operations. Other polymer materials that incorporate the design include all thermoplastic and thermoset polymers, rubber polymers, foam polymers, wood filled polymers, organic and inorganic filled polymers organic and inorganic reinforced polymers, wood and metal materials, and other moldable and formable materials. Variations on the manufacturing method include all common thermoplastic and thermoset manufacturing processes, including, extrusion, injection molding, compression molding, Reaction Injection Molding (RIM), thermoforming, rotational molding, Resin Transfer Molding (RTM). The extruded annular section is extruded to the desired length. The extruded sections are then snapped together to form modular sections, e.g., sections 1 , 2 , 3 , 4 , 5 , and 6 , as shown in FIG. 1 . The cross section can include one, two, three, or more hollow sections as determined by the forming die.
[0047] The formed pallet subassembly sections can be joined together in the manner illustrated in FIG. 4 , with a cross piece 600 that will join two sections that both have flanges or both have groove sections. The length of the tubular members are determine by cutting them to a particular length at the manufacturing operation. Cutting longer tubular members or connecting the ends of tubular members with connecting pieces, as illustrated in FIG. 1 , can increase the lengths. The middle connecting piece 300 is a short piece of that snugly fits in the ends of the tubular members 880 . It will fit in the ends much like a wooden dowel fits in the ends of straws to produce a very long straw structure. The length of the connecting piece depends upon the choice of how much engagement is desired between the pieces, where half of the connecting piece is in one tubular member and the other half is in the connected tubular member. Typical, lengths of the connecting piece can be 2 inches to 8 inches.
[0048] After establishing interlocking assembly of the interlocking sections, securing the interlocking sections in permanent and immovable assembly can be further assisted by the use of various additional pieces. FIG. 1 shows such a support structure in the form of a pallet of a plurality of modular tubular sections. As shown in FIG. 1 , an example of a pallet structure utilizing the present invention can have six tubular sections that have a interlocking tubular section as described but not limited to FIG. 2 and FIG. 3 and are connected with pallet cross pieces as shown in FIG. 4 .
[0049] The pallet cross piece 600 ( FIG. 4 ) connects the edges of two adjoining pallet sections that have a flange on one side and a groove on the opposite side as shown in but not limited to FIGS. 2 and 3 . The interlocking tubular sections, e.g., sections 1 , 2 , 3 , 4 , 5 , and 6 in FIG. 1 , may also be connected on the annular end with middle connecting piece 300 and 400 as shown in FIG. 1 .
[0050] The modular sections can be made from 2 , 3 , 4 , 5 , or any number of sections, and additional pallet sections to be added to the ends of the tubular sections as well, with the use of middle connecting pieces 300 , as shown in FIG. 6 . The pallet is thus modular in both length and width, with no gap in the continuous surface, even at or near the attachment points.
[0051] Also, the interlocking tubular sections, e.g., sections 1 , 2 , 3 , 4 , 5 , and 6 in FIG. 1 , may have end pieces 200 and 500 in FIG. 1 to close off the annular end of the tubular section and give the appearance of a solid section. The open ends of the tubular sections may not be desired as a product feature and so can be closed off with end pieces 500 in the manner illustrated in FIG. 1 . The end piece 500 , shown in FIG. 7 , can act as an end cap for the tubular section so that tubular opening can be closed off and prevent foreign objects, rain, debris, rodents, or other items from collecting on the inside of the pallet. The end pieces are very similar in design as the connecting pieces 300 but have a truncated end.
[0052] When two subassembly sections come together at the center of the pallet, the sections cannot connect since both sections will have grooves butting together. As shown in FIG. 4 , a pallet cross piece 600 connects the two groove sections since it has two flange regions on the left and right sides. It does not have a groove section as shown in fragmentary section view of FIG. 3 , which shows interlocking geometry of rectangular cross-sectional configuration being employed to establish interlocking between pallet sections. The pallet sections interlock in a similar way as the flanges 52 , 54 , 56 , 58 from the pallet cross piece lock in the grooves of the pallet sections 62 , 64 , 66 , and 68 .
[0053] In FIG. 4 , the illustration depicts a left-handed flange with three hollow sections 700 , a right-handed flange with three hollow sections 800 , and a pallet cross piece 600 . The right-handed flange with three hollow section profile 800 is repeated with similar sections many times to the right until section 1 is built. Similarly, the left-handed flange with three hollow section profile 700 is repeated with similar sections many times to the left until section 4 is built. Modular section 1 is connected with modular section 4 with the use of pallet cross piece 600 . The pallet cross-piece can also be made with thicker wall sections to increase the rigidity of the cross section and provide a more rigid pallet. Similarly, a dual connector middle piece 300 is used to connect section 4 with section 5 , as illustrated in FIG. 1 . Sections 4 and 5 are connected with the tubular ends of the modular section.
[0054] The middle or dual connector piece 300 is also used to connect sections 1 to 2 , sections 2 to 3 , and sections 5 to 6 . The modular design of the tubular sections allows for the continuous structure to be divided into several regions for ease of repair or serviceability. The modular sections are connected together with the snap fit assembly to form the overall structure shown as an example in FIG. 1 .
[0055] With the interlocking modular sections the support structure, pallet, deck or other article, can be repaired less expensively and much easier than a single unit type of construction. If several modular sections are combined to make a structure, then if one section is damaged, it can be replaced by disconnecting the one bad section from the whole unit and replacing the bad section with a good section. The air sections formed by the annular nature of the tubes makes them substantially lighter than most conventional pallet and decking or related materials.
[0056] Although six pallet tubes or sections are shown, such is not intended to limit the spirit and scope of the present invention because any suitable number of interconnected tubes or sections may be utilized. Also, elements or sections in the form of structures other than tubular elements or sections may be also within the spirit and scope of the present invention. It is only necessary that the sections that are assembled to form a pallet structure integrity to support objects or articles of predetermined maximum weight and that the pallet be capable of being supported in a floor surface and that the pallet present a substantially planar upper surface on which articles may be stacked.
[0057] A pallet produced from the tubular sections would be lighter, less expensive, and easier to repair than current aircraft pallets made from balsa wood and aluminum skins. The continuous top surface provides a continuous support for loading along the edges will not result in a gap between the decks even if only supported at the ends.
[0058] The modular sections can comprise two or more sections that snap in to one or several units. As an example, the pallet structure in FIG. 1 depicts 6 modular sections and cross pieces that are further illustrated in Section A-A ( FIG. 4 ) and Section B-B ( FIG. 5 ). Section A-A illustrates the use of the design for the thermoplastic material, though it also sufficiently describes the design for metallic, plastic, composite, or other polymer materials. Alternate versions of the invention include other designs with tabs that interlock, other manufacturing processes for polymer materials, and other polymer-based, organic-based, and metallic-based materials. Variations on the design include manners to snap-fit pieces of tubular sections to form a modular structure. This can include other flange designs on the end of the cross section and the mating tubular or solid sections. Additionally, if desired, the interlocking tubular sections of the top walls can be secured by adhesive, welding, bonding agent, or mechanical fasteners so that the resulting joint is of permanent and the pallet sections form an integral pallet unit. Also, the pallet section joint may be heat or chemically fused during assembly to prevent inadvertent separation of the pallet sections during use.
[0059] Sections 300 and 500 ( FIGS. 6 and 7 , respectively) are depicted as friction fit connectors. Section 300 is the middle connecting piece that connects the ends of two tubular sections. The tubular section may need several pieces of the 300 part depending on how many openings are in each end section as shown in FIG. 2 and for surfaces 20 and 30 . Typically three connection sections are needed for each tubular sections. Similarly, several end pieces ( 200 and 500 ) may be needed to close out the section and make it look solid.
[0060] The benefits of the connecting pieces are to provide local structure for the pallet (or decking) and to enable it to be modular in the length direction. The number of connecting sections and the length between sections can vary depending upon the application. Some pallet (or decking) designs might require close spacing of the tubular sections, whereas, other designs might require very large spacing between sections. The thickness of the connecting pieces can also vary depending upon the application. The connecting pieces allows an increase in thickness at the connection and thus stiffening the section since it is thicker. The connecting pieces can be designed to accept fasteners or attachment devices for the pallet.
[0061] If a tubular section breaks, the connecting pieces allow the pallet to be disassembled and the damaged part replaced with a new section. The connecting pieces can be hollow or solid. The connecting pieces can be made from plastic, metal, wood, ceramic, rubber, polymer composite, or other suitable material. The repair and reassembly can occur at the end user's location, which will reduce the cost of repair and shipping.
[0062] While this invention has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of this invention.
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A modular section for forming a support structure, the section being elongated and having a generally annular cross-sectional configuration with spaced upper and lower surfaces and spaced side walls, the upper and lower surfaces and side walls forming upper and lower edges, respectively, at the interfaces, wherein the upper and lower surfaces each comprise an extension at the respective upper and lower edges, the extensions having a flange formed at the ends thereof, and where the upper and lower surfaces each have a groove formed therein.
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FIELD OF THE INVENTION
The present invention concerns the synthesis of gabapentin precursors. A new process is described for synthesising cyclohexanediacetic acid monoamide.
PRIOR ART
Cyclohexanediacetic acid monoamide, or 3,3-pentamethylene mono glutaramide, hereinafter known as MAAC, is an important intermediate for preparing a medicinal known by the generic name of Gabapentin, [1-(aminomethyl)cyclohexyl]acetic acid. The preparation of MAAC is described for example in U.S. Pat. No. 4,024,175 and WO 03002517, by treating 3,3-pentamethyleneglutaric anhydride with aqueous ammonia. The pentamethyleneglutaric anhydride in turn is obtained from cyclohexanediacetic acid, which is prepared by acid hydrolysis of the cyclic imide known by the IUPAC name 1,5-dicarbonitrile-2,4-dioxo-3-azaspiro[5,5]undecane. This cyclic imide is in turn obtained from cyclohexanone with ethyl cyanoacetate. This long series of passages is described for example in patents U.S. Pat. Nos. 5,132,451, 6,521,788, 6,613,904, WO 03002504 and others. The synthesis sequence is summarised in scheme 1.
Some of the reactions in Scheme 1 are particularly difficult and onerous to apply industrially. For example the transformation of cyclohexanone into the cyclic imide II requires reaction times of about 72 hours (see for example GB 898692), while hydrolysis of the imide II into the diacid III occurs at high temperature in the presence of concentrated sulphuric acid, and involves the production of large quantities of waste products. There is therefore a strong need for a method for preparing MAAC which avoids the difficulties described, being both industrially convenient and ecologically compatible.
SUMMARY OF THE INVENTION
A new process is described for synthesising cyclohexanediacetic acid monoamide (3,3-pentamethylene mono glutaramide), a key compound in the synthesis of gabapentin precursors.
The process of the invention is characterised by reacting cyclohexanone with cyanoacetamide and thereafter, with a suitable malonic acid ester. A new intermediate (5-cyano-2,4-dioxo-3-azaspiro[5,5]undecane-1-carboxylic acid ester) is obtained which is convertable, under mild reaction conditions, into cyclohexanediacetic acid monoamide.
DETAILED DESCRIPTION OF THE INVENTION
This invention provides a simplified process for preparing MAAC. This process is based on the preparation of a new intermediate, not previously described, which can be easily transformed into the monoamide V. This intermediate has the formula VI:
where R can be hydrogen, alkyl, substituted alkyl, benzyl; preferred examples of alkyls are C1-C10 and more preferably C1-C5 alkyls.
While being structurally similar to the imide II, the reactivity of the new imide VI is very different. It is known that transformation of the imide II into cyclohexanediacetic acid III requires the use of sulphuric acid at high temperature. Patent WO 03002504 hypothesises that during the reaction, a tricyclic compound may form which would be particularly stable.
The cyclohexaneacetic acid thus obtained is transformed into MAAC by means of the two successive reactions of anhydride formation and ammonolysis. A three step process is involved, the first of which requires particularly severe conditions. Instead, it has been established that the imide VI can be transformed into MAAC in only two reaction passages which both occur under particularly mild conditions. In conclusion, the imide VI can be prepared by much faster reactions than the imide II and can be transformed into MAAC by a more direct process under milder conditions.
The imide VI can be prepared starting from raw materials which are easily available and of low cost. The synthesis sequence is the following:
Reaction 1. consists of condensing the cyclohexanone (I) with cyanoacetamide, to obtain 2-cyclohexylidene-2-cyanoacetamide (IX); this reaction can be undertaken for example in toluene, in the presence of ammonium acetate and acetic acid, heating to a temperature between 20 and 150° C., and preferably to the reflux temperature of the reaction mixture; the compound IX is separated from the reaction mixture.
Reaction 2. consists of condensing 2-cyclohexylidene-2-cyanoacetamide with the malonic acid ester shown above, where R′ and R″, the same or different, represent alkyl, substituted alkyl, benzyl. The reaction is carried out in the presence of a base, such as sodium hydride or sodium alcoholate; the compound VI, where R represents alkyl, substituted alkyl or benzyl, is obtained by then acidifying the reaction mixture; the compound VI where R is H can be easily obtained by subjecting the product VI where R is e.g. benzyl to catalytic hydrogenation, for example in the presence of Pd/C.
Reactions 1. and 2. can also be undertaken by operating in a single reactor and without isolating the compound IX; the reaction therefore takes place according to the following scheme:
where R has the aforesaid meanings.
Transformation of the imide VI into MAAC (V) can be favourably obtained under mild conditions with classical organic chemistry methods, for example by hydrolysis and decarboxylation; the intermediate VII is thus obtained, which is further hydrolysed to obtain MAAC (V).
In the passage VI to VII, hydrolysis can be undertaken in a basic environment (achieved for example with an alkali or alkaline-earth metal hydroxide) and decarboxylation by subsequent acidification of the reaction mixture. Hydrolysis of the cyano group can be possibly favoured by the presence of hydrogen peroxide, or by reagents and operating conditions given in the literature (see for example S. March, Advanced Organic Chemistry, 4th Edition, New York, 1992, pages 887-888; R. C. Larock, Comprehensive Organic Transformations, 2nd Edition, New York, pages. 1986-1987).
Given the acidic nature of the hydrogen of the imide group, it is presumed that hydrolysis in a basic environment takes place on the anion of the amide VI having the following formula
Decarboxylation can be undertaken in an acid environment, for example with an acid hydrohalogen or sulphuric acid.
Subsequent hydrolysis of VII to V can be undertaken for example by heating with alkali in an aqueous environment; after cooling, the product V precipitates by acidification.
The passages VI→VII→V can also be effected continuously in the same reactor, thus without the need to isolate the intermediate VII.
The products derived from hydrolysis of the imide VI, usable as intermediates for preparing gabapentin (X), are numerous and enable alternative pathways for synthesising the active principle to be chosen. Scheme 2 indicates the various possibilities:
The aforedescribed invention is illustrated by the following non-limiting examples.
EXPERIMENTAL PART
Example 1
Synthesis of 2-cyclohexylidene-2-cyanoacetamide (IX)
600 ml of toluene, 200 g of cyanoacetamide, 193 g of cyclohexanone, 15 g of ammonium acetate and 24 g of acetic acid are placed in a 2 litre flask equipped with a mechanical stirrer, thermometer and Dean-Stark trap connected to a condenser, under nitrogen flow. The mixture is heated under reflux, simultaneously separating the water by distilling the water-toluene azeotrope. The separated water is collected in the Dean-Stark trap and removed at suitable time intervals. After 2 hours, on completion of the azeotropic distillation, it is cooled to 70° C., washed with 400 ml of a saturated sodium bicarbonate solution and cooled to 15° C. The precipitated solid is filtered off, washed with 70 ml of toluene, then 70 ml of water and dried in an oven at 40° C. under vacuum. 213 g of 2-cyclohexylidene-2-cyanoacetamide are obtained.
Example 2
Synthesis of ethyl 5-cyano-2,4-dioxo-3-azaspiro[5,5]undecane-1-carboxylate (VI)
0.69 g of sodium metal are suspended in 30 ml of anhydrous ethanol in a 100 ml flask equipped with a magnetic stirrer, thermometer and condenser, in a nitrogen atmosphere. When the sodium has dissolved, 4.8 g of diethylmalonate are added followed, after 15 minutes, by 4.92 g of cyclohexylidenecyanoacetamide. The mixture is left for 1 hour under agitation at 25° C. and then acidified with 36% HCl. The solid obtained is filtered off and dried under vacuum. 6.84 g of ethyl 5-cyano-2,4-dioxo-3-azaspiro[5,5]undecane-1-carboxylate are obtained.
Melting range: 167-170° C. 1 H-NMR (acetone-d6, 200 MHz), δ(ppm): 4.60 (s, 1H), 4.28 (q, 2H), 4.09 (s, 1H), 1.8-1.5 (m, 10H), 1.39 (t, 3H). 13 C-NMR (DMSO-d6, 75.4 MHz), δ(ppm): 167.97, 167.12, 165.29, 115.07, 62.21, 52.48, 40.69, 38.73, 35.11, 31.08, 24.58, 20.30, 20.17, 13.77.
Example 3
Synthesis of methyl 5-cyano-2,4-dioxo-3-azaspiro[5,5]undecane-1-carboxylate (VI)
24 ml of a 5.4 M solution of sodium methylate in methanol, 17.7 g of dimethylmalonate and 100 ml of methanol are placed in a 250 ml flask equipped with a mechanical stirrer, thermometer and condenser, under nitrogen flow. After 30 minutes, when the sodium has completely dissolved, a suspension of 20 g cyclohexylidenecyanoacetamide in 50 ml of methanol is added over a period of 15 minutes. The reaction mixture is left under agitation for 1 hour at 25° C. and is subsequently acidified with 5% HCl. The solid obtained is filtered off, washed with methanol and dried under vacuum. 28 g of methyl 5-cyano-2,4-dioxo-3-azaspiro[5,5]undecane-1-carboxylate are obtained.
HPLC-MS: [M-H] − : 263 Melting range: 180.5-181.2° C.
Example 4
Synthesis of benzyl 5-cyano-2,4-dioxo-3-azaspiro[5,5]undecane-1-carboxylate (VI)
3.41 g of dibenzylmalonate, 30 ml of toluene and 0.58 g of 60% sodium hydride in mineral oil are placed in a 100 ml flask equipped with a magnetic stirrer, thermometer and condenser, in a nitrogen atmosphere. After 15 minutes, 1.97 g of cyclohexylidenecyanoacetamide are added. The reaction mixture is left under agitation for 6 hours at 25° C. and is then acidified with 36% HCl. The organic phase is separated and the solvent is evaporated under reduced pressure to obtain 3.18 g of benzyl 5-cyano-2,4-dioxo-3-azaspiro[5,5]undecane-1-carboxylate.
Melting range: 153-156° C. 1 H-NMR (CDCl 3 , 200 MHz), δ(ppm): 8.2 (bs, 1H), 7.5-7.4 (m, 5H), 5.34, 5.15 (AB system, J=14 Hz, 2H), 4.5 (s, 1H), 4.1 (s, 1H), 1.8-1.1 (m, 10H).
Example 5
Synthesis of 5-cyano-2,4-dioxo-3-azaspiro[5,5]undecane-1-carboxylic acid (VI)
1.8 g of benzyl 5-cyano-2,4-dioxo-3-azaspiro[5,5]undecane-1-carboxylate, 25 ml of ethyl acetate and 0.09 g of 5% Pd/C are placed in a 100 ml flask equipped with a magnetic stirrer, thermometer and condenser. The mixture is stirred for 4 hours at 12° C. under a hydrogen atmosphere. 10 ml methanol are added and the mixture is filtered through celite. The solvent is evaporated at 20° C. under reduced pressure to obtain 1.32 g of 5-cyano-2,4-dioxo-3-azaspiro[5,5]undecane-1-carboxylic acid.
Melting range: 210-214° C. 1 H-NMR (DMSO-d6, 200 MHz), δ(ppm): 11.8 (s, 1H), 4.7 (s, 1H), 3.9 (s, 1H), 1.8-1.0 (m, 10H).
Example 6
Synthesis of 2,4-dioxo-3-azaspiro[5,5]undecane (VII)
10 g of methyl 5-cyano-2,4-dioxo-3-azaspiro[5,5]undecane-1-carboxylate and 5 g of NaOH dissolved in 125 ml of 2:1 ethanol/water are placed in a 250 ml flask equipped with mechanical agitator, thermometer and condenser. The mixture is heated under reflux for 1.5 hours, acidified with 5% HCl to pH 2 and heated under reflux for 3 hours. By cooling to 20° C. a precipitate is formed which is filtered off, washed with water and dried under vacuum. 4.7 g of 2,4-dioxo-3-azaspiro[5,5]undecane are obtained.
Example 7
Synthesis of 2,4-dioxo-3-azaspiro[5,5]undecane (VII)
204 ml of a 5.4 M solution of sodium methylate in methanol, 550 ml methanol and 145.5 g of dimethylmalonate are placed in a 2 litre flask equipped with a mechanical stirrer, thermometer and condenser, under nitrogen flow. After 30 minutes, 148 g of cyclohexylidenecyanoacetamide are added over a period of 30 minutes. The mixture is left under agitation for 1.5 hours at 30° C., after which 626 g of 15% NaOH are added, then heated under reflux for 1.5 hours. 400 ml of methanol are distilled and the mixture is acidified with 36% HCl to pH 3 then heated under reflux for 3 hours. By cooling to 25° C. a precipitate is formed which is filtered off, washed with water until the washing waters are neutral and dried under vacuum at 45° C. 69 g of 2,4-dioxo-3-azaspiro[5,5]undecane are obtained.
Example 8
Synthesis of cyclohexanediacetic acid monoamide (V)
9 g of 2,4-dioxo-3-azaspiro[5,5]undecane and 30 g of 10% NaOH are placed in a 250 ml flask equipped with mechanical agitator, thermometer and condenser. The mixture is heated under reflux for 1 hour, cooled to 25° C. and acidified with 36% HCl to pH 5. The precipitate formed is filtered off, washed with water and dried under vacuum. 6.4 g of cyclohexanediacetic acid monoamide are obtained.
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A new process is described for synthesising cyclohexanediacetic acid monoamide, a key compound in the synthesis of grabapentin precursors. The process of the invention is characterised by reacting cyclohexanone with cynoacetamide and immediately after, with a suitable malonic acid ester. A new intermediate (5-cyano-2,4-dioxo-3-azaspiro[5,5]undecane-1-carboxylic acid ester) is obtained which is convertible, under mild reaction conditions, into cyclohexanediacetic acid monoamide.
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FIELD OF THE INVENTION
The present invention relates to a deodorizing material useful for the removal of malodorous substances which are present in rooms, refrigerators, etc. or under various environment and to a process for producing the same.
BACKGROUND OF THE INVENTION
As deodorizing materials for removing malodorous substances, such as ammonia, methyl mercaptan, methyl sulfide dimethyl disulfide, hydrogen sulfide and trimethylamine, which are present in rooms, refrigerators, etc., there have hitherto been proposed those consisting mainly of activated carbon; those consisting of fibers or the like to which phthalocyanine complexes are attached; and those consisting of a carboxymethylated cellulose on which copper and/or zinc ions are adsorbed.
However, deodorants consisting mainly of activated carbon are in the form of granules, and they are colored in black. Therefore, the deodorants so employed are contained in a good-looking package. This results in bulkiness and poses various constraints on their use.
Deodorants consisting of fibers, such as celluloses, to which phthalocyanine complexes are attached are slow in the speed of deodorization and hence their deodorizing capability is insufficient from practical point of view.
Deodorants comprising carboxymethylated cellulose fibers on which copper and/or zinc ions are adsorbed could hardly be said to be a practical deodorizer since the ions are adsorbed thereon in only small quantities.
There has also been reported cellulose fibers dipped in a concentrated alkali solution of a copper compound to attain an increase in the quantity of ions adsorbed thereon. However, cellulose fibers so treated are severely damaged by the strong alkali and hence become unsatisfactory in workability, processability and other practical properties.
It has therefore been desired to develop a deodorizing material which is excellent in processability and exhibits excellent deodorizing properties.
SUMMARY OF THE INVENTION
As a result of intensive investigations, it has now been found that copper hydroxide and/or zinc hydroxide can be effectively attached to and fixed on cellulose fibers under certain conditions and that the fixed fibers so obtained exhibit excellent deodorizing effects against a wide range of malodorous substances, and the present invention has been accomplished on the basis of the finding.
Accordingly, the present invention is concerned with:
1) A process for producing deodorizing fibers, which is characterized in that copper hydroxide and/or zinc hydroxide is attached to cellulose fibers in a colloidal state and fixed thereon.
2) A process for producing deodorizing fibers as described in 1), wherein an alkaline substance is added to an aqueous solution of a water-soluble copper compound and/or a water-soluble zinc compound in which cellulose fibers are dispersed, so as to form colloid of copper hydroxide and/or zinc hydroxide and to fix the copper hydroxide and/or zinc hydroxide on said cellulose fibers through contact between them.
3) A process for producing deodorizing fibers as described in 1), wherein an alkaline substance is added to an aqueous solution of a water-soluble copper compound and/or a water-soluble zinc compound to form colloid of copper hydroxide and/or zinc hydroxide, and then cellulose fibers are charged and dispersed into the colloidal solution to fix the copper hydroxide and/or zinc hydroxide on the fibers through contact between them.
4) A process for producing deodorizing fibers as described in 1), wherein said cellulose fibers are treated with an acid before being dispersed into said aqueous solution of a water-soluble copper compound and/or a water-soluble zinc compound.
5) A process for producing deodorizing fibers as described in 1), wherein said cellulose fibers are dipped in an aqueous solution of chitosan before being dispersed into said aqueous solution of a water-soluble copper compound and/or zinc compound.
6) Deodorizing fibers consisting of cellulose fibers on which copper hydroxide and/or zinc hydroxide is attached and fixed in a colloidal state.
7) Deodorizing fibers as described in 6), wherein said copper hydroxide and/or zinc hydroxide is fixed on said cellulose fibers via a layer of chitosan.
8) Cellulose fibers as described in 6), wherein said cellulose fibers are pulp fibers.
9) A deodorizing material which comprises cellulose fibers on which copper hydroxide and/or zinc hydroxide is attached and fixed in a colloidal state.
10) A deodorizing material as described in 9), wherein said material is in the form of a sheet.
As examples of cellulose fibers usable in the present invention, mention may be made of pulp fibers, such as bleached sulfite pulps (e.g., NBSP, LBSP, NDSP, LDSP, etc.) and bleached kraft pulps (e.g., NBKP, LBKP, etc.); flaxes, such as Manila hemp, jute, etc.; cottons, such as cotton wool, cotton linter, etc.; natural fibers of kozo (paper mulberry), mitsumata (Edgeworthis papyrifera), etc. and their pulpy derivatives; rayon; and oxidized cellulose-containing fibers obtainable through oxidation of these fibers. These cellulose fibers can be used either individually or in combination of two or more of them.
In the present invention, deodorizing fibers are produced by fixing copper hydroxide and/or zinc hydroxide on at least one of the above-mentioned cellulose fibers by means of contact with a liquid containing colloids of copper hydroxide and/or zinc hydroxide.
If cellulose fibers are dipped in a dispersion containing copper hydroxide and/or zinc hydroxide in a non-colloidal solid state, the components could hardly be fixed strongly on the fibers, and particles of the components easily drop off during handling, resulting in a product which is not a practical deodorizer.
On the other hand, if cellulose fibers are dipped in a solution of copper hydroxide and/or zinc hydroxide in which no colloids are formed, the copper hydroxide and/or zinc hydroxide will attach to the cellulose fibers in only small quantities, and hence there will result a product which is only unsatisfactory as a practical deodorizing material.
Copper hydroxide and/or zinc hydroxide can be attached to and fixed on cellulose fibers in a colloidal state, e.g., in the following manner:
Method for Fixing
To an aqueous solution of a water-soluble copper compound and/or a water-soluble zinc compound in which cellulose fibers are dispersed is added an alkaline substance, so as to form colloid by adjusting its pH to 4.5 to 12 in the case of a copper compound or to 6.2 to 12 in the case of a zinc compound, preferably to 8.0 to 9.5 in either case. Or colloid is formed in the above manner, and then cellulose fibers are charged and dispersed into the colloid-containing solution. Copper hydroxide and/or zinc hydroxide is attached to and fixed on the cellulose fibers by way of contact between the colloid-containing solution and the fibers Colloidal particles could hardly be formed unless the pH is in the range of 4.5 to 12 in the case of a copper compound or in the range of 6.2 to 12 in the case of a zinc compound If the fixation is carried out at a pH lower than 8.0, the quantity of fixed compounds and the rate of their fixing will become lower and, on the contrary, if it is effected at a pH higher than 9.5, the cellulose fibers tend to become brittle. The pH range of from 8.0 to 9.5 is therefore preferred. The cellulose fibers, when subjected to the fixation at a relatively high pH, are preferably washed well with water.
In cases, in particular, where the pH is higher than ca. 12, the fibers are severely damaged since they are cellulosic, and after treatment of the resulting fibers, such as washing or the like, must be intensified. In addition, there will result an undesirable lowering in the strength of the fibers and deterioration in their processability.
In the deodorizing fibers of the present invention, the components which contribute to their capability of deodorization are present on the surface of the fibers and come into contact with malodorous gases, the subjects for deodorization, in an effective manner. Because of this, the deodorizing fibers provide an improved deodorizing effect compared with fibers obtained by means of dipping in a simple aqueous solution of a copper compound.
In the above-described preparation of aqueous solution of a water-soluble copper compound and/or a water-soluble zinc compound, the concentration of the components must be within the range where it is possible to form a colloidal solution when the pH is adjusted later.
Cellulose fibers can be subjected to an acid treatment by using, e.g., hydrochloric acid, sulfuric acid, sulfurous acid, nitric acid, etc. before being dispersed into the aqueous solution of a water-soluble copper and/or zinc compound. Alternatively, cellulose fibers can be subjected to a chitosan treatment, dipping them in an aqueous acidic solution of chitosan, so as to attain an enhancement in the quantity of the desired hydroxides attached thereto. This effect is particularly marked when zinc hydroxide is employed.
There are no particular restrictions on water-soluble copper and zinc compounds to be used in the present invention. Any copper and zinc compounds can be used only if they are soluble in water. As examples of such compounds, mention may be made of copper sulfate, copper chloride, copper nitrate, copper acetate, zinc sulfate, zinc chloride, zinc nitrate, zinc acetate, and the like.
As alkaline substances for providing alkalinity, there can be used any compounds which are capable of reacting with the above-described copper and zinc compounds to form colloidal copper hydroxide and/or zinc hydroxide. As examples of such alkaline substances, mention may be made of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, and the like. Of these compounds, sodium hydroxide and potassium hydroxide can be preferable because of easiness of the pH adjustment.
Deodorizing fibers obtained through the hydroxide-fixing treatment and, where desired, washing with water and drying described hereinbefore can be used as they are as a deodorizing material or can be shaped into a sheet-like product which is made by a conventional paper milling method or a three-dimensional product to be used as a deodorizing material.
Upon the production of shaped products, there can be used more than one kind of cellulose fibers which have copper and/or zinc hydroxide fixed thereon, and it is possible to use the cellulose fibers together with cellulose fibers and/or other fibers not fixed with copper and/or zinc hydroxide, within the limits where the required deodorizing capability can be satisfied. In cases where they are shaped into a sheet-like product, granules, or the like, it is possible to incorporate therein auxiliary agents conventionally used for paper milling, such as wet strength intensifiers, polymeric coagulants, etc., within the limits that the practical deodorizing capability of the shaped product is not impaired.
Furthermore, it is possible to subject the thus obtained shaped products to a secondary processing, such as surface printing, lamination with other materials, folding, and shaping into a three-dimensional form.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention will further be explained in detail by way of examples. However, the invention is by no means limited to these.
Analytical values shown in the examples were determined in the following manner:
(1) Concentration of Cu and Zn
Determined by the atomic absorption photometry.
(2) Relative viscosity
Measured in accordance with JIS P 8101.
(3) Moisture content in samples
Measured in accordance with JIS P 8203.
(4) Deodorizing capability
Into a 1.5 liter polyvinyl chloride bag were charged 1 g of a sample of a deodorant and 1.5 liters of a malodorous gas of a predetermined concentration (100 ppm in each case), and then the bag was sealed. The concentration of the malodorous gas remaining in the bag was measured with a gas detection tube immediately after the sealing and 10, 30 and 60 minutes after the sealing, and the remaining rate (%) of the gas was calculated therefrom.
EXAMPLES 1-3
To 20 liters of water was added 1,000 g of NBSP, of bleached sulfite pulps (used as a cellulose fiber), and the mixture was disaggregated to a pulpy state by using a disaggregator and then subjected to an acid treatment by the addition of an aqueous SO 2 solution up to a pH of 3.3. Subsequently, an aqueous copper sulfate solution containing 200 g/l of CuSO 4 .5H 2 O was added thereto up to a concentration of 3 W/W% (reduced to copper and based on the weight of the NBSP). Then, the pH of the mixture was adjusted to 5.0, 6.0 or 9.5 (Example 1, 2 and 3, respectively) by using an aqueous solution of sodium hydroxide (120 g/l), whereby colloid of copper hydroxide was formed, and the colloid formed was attached to, and fixed on, the NBSP fibers to produce deodorizing fibers. The thus obtained fibers were shaped into sheets by using a sheet machine and then dried to give sheets of ca. 410 g/m 2 . The quantity of copper hydroxide fixed on each sheet was determined (in W/W% reduced to copper and based on the weight of the NBSP), and the rate(%) of copper fixed, based on the weight of copper added, was calculated therefrom. Results obtained are shown in Table 1.
It would be apparent from the results that excellent fixed quantities and fixed rates could be attained at a pH of 6.0 and above.
EXAMPLES 4-6
To 20 liters of water was added 1,000 g of NBSP (cellulose fiber), and the mixture was disaggregated to a pulpy state by using a disaggregator, and its pH was adjusted to 3.0 by the addition of an aqueous SO 2 solution. Subsequently, an aqueous zinc sulfate solution containing 200 g/l of ZnSO 4 was added thereto up to a concentration of 3 W/W% (reduced to zinc and based on the weight of the NBSP). Then, the pH of the mixture was adjusted to 6.5, 8.0 or 9.5 (Example 4, 5 or 6, respectively) by using an aqueous solution of sodium hydroxide (120 g/l), whereby colloid of zinc hydroxide was formed, and the colloid formed was attached to, and fixed on, the NBSP fibers to produce deodorizing fibers. The thus obtained fibers were shaped into sheets by using a sheet machine and then dried to give sheets of ca. 410 g/m 2 . The quantity of zinc hydroxide fixed on each sheet was determined (in W/W% reduced to zinc and based on the weight of the NBSP), and the rate(%) of zinc fixed, based on the weight of zinc added, was calculated therefrom. Results obtained are also shown in Table 1.
It would be apparent from the results that excellent fixed quantities and fixed rates could be attained at a pH of 8.0 and above.
EXAMPLES 7-9
To 20 liters of water was added 1,000 g of NBSP, and the mixture was disaggregated to a pulpy state by using a disaggregator and then subjected to an acid treatment by the addition of an aqueous SO 2 solution up to a pH of 3.3. Subsequently, an aqueous copper solution containing 200 g/l of CuSO 4 .5H 2 O was added thereto in quantities as shown in Table 1 based on weight reduced to copper (Examples 7, 8 and 9). Then, the pH of the mixtures was adjusted to 8 by the addition of an aqueous solution of sodium hydroxide (120 g/l), whereby colloid of copper hydroxide was formed, and the colloid formed was attached to, and fixed on, the NBSP fibers to produce deodorizing fibers. The thus obtained fibers were shaped into sheets by using a sheet machine and then dried to give sheets of ca. 410 g/m 2 .
The quantity of copper hydroxide fixed on each of the sheets was determined (in W/W% reduced to copper and based on the weight of the NBSP), and the rate(%) of copper fixed, based on the weight of copper added, was calculated therefrom. Results obtained are shown in Table 2.
Thereafter, deodorizing capability for H 2 S gas, NH 3 gas and methyl mercaptan gas of the products according to Examples 7, 8 and 9 was evaluated in accordance with the test method shown hereinbefore. Results obtained are also shown in Table 3.
It would be apparent from the results shown in Tables 2 and 3 that the deodorizing materials according to the invention are capable of effectively acting on such malodorous gaseous substances as H 2 S, NH 3 and methyl mercaptan.
EXAMPLES 10-11
To 20 liters of water was added 1,000 g of NBSP (cellulose fiber), and the mixture was disaggregated to a pulpy state by using a disaggregator, and its pH was adjusted to 3.0 by the addition of an aqueous SO 2 solution. Subsequently, an aqueous zinc sulfate solution was added thereto up to a concentration of 2 or 6 W/W% (reduced to zinc and based on the weight of the NBSP) [Example 10 or 11, respectively]. Then, the pH of the mixtures was adjusted to 8 by the addition of an aqueous solution of sodium hydroxide (120 g/l), whereby colloid of zinc hydroxide was formed, and the colloid formed was attached to, and fixed on, the NBSP fibers to produce deodorizing fibers. The thus obtained fibers were shaped into sheets by using a sheet machine and then dried to give sheets of ca. 410 g/m 2 .
The quantity of zinc hydroxide fixed on each of the sheets was determined (in W/W% reduced to zinc and based on the weight of the NBSP), and the rate(%) of zinc fixed, based on the weight of zinc added, was calculated therefrom. Results obtained are also shown in Table 2.
Thereafter, the deodorizing capability for H 2 S gas and NH 3 gas of the products according to Examples 10 and 11 was evaluated in accordance with the test method described hereinbefore. It would be apparent from the results shown in Table 2 that the cellulose fibers on which zinc hydroxide is fixed possess the capability of deodorizing H 2 S gas and NH 3 gas.
EXAMPLE 12
Disaggregated and acid treated slurry of NBSP fibers was prepared in the same manner as in the case of aqueous-copper sulfate solution in Example 9, and copper sulfate and zinc sulfate were added thereto in the same manner as in Example 9, up to a concentration of 2% by weight each (reduced to copper or zinc and based on the weight of the fibers). Subsequently, the pH of the mixture was adjusted to 8 by the addition of an aqueous solution of sodium hydroxide (120 g/l), whereby a copper hydroxide and zinc hydroxide-containing colloid was formed, and the colloid formed was attached to, and fixed on, the NBSP fibers to produce deodorizing fibers. The fibers obtained were shaped into a sheet by using a sheet machine and then dried to give a sheet of ca. 410 g/m 2 .
Thereafter, the deodorizing capability for H 2 S gas and NH 3 gas of the thus obtained sheet was evaluated in accordance with the test method described hereinbefore. Results obtained are also shown in Table 2.
It would be apparent from the results shown in Table 2 that the deodorizing material according to the invention is capable of effectively acting on such malodorous gaseous substances as H 2 S and NH 3 .
Fixed quantity:
Cu: 1.8% by weight
Zn: 1.3% by weight
Deodorizing capability:
______________________________________Immediately After After Afterafter sealing 10 min. 30 min. 60 min.______________________________________H.sub.2 S 30 2 0NH.sub.3 19 7 0______________________________________
EXAMPLE 13
To 20 liters of water was added 1,000 g of NBSP (oxidized cellulose fiber), and the mixture was disaggregated to a slurry by using a disaggregator. An aqueous 1 wt % chitosan solution in 1 wt % acetic acid was added to the mixture, up to a concentration of chitosan of 1.0% by weight, based on the weight of the NBSP, and the resulting mixture was stirred for 15 minutes. Thereafter, an aqueous zinc sulfate solution was added thereto up to a concentration of zinc of 6 W/W%, based on the weight of the NBSP. Then, the pH of the mixture was adjusted to 8 by the addition of an aqueous solution of sodium hydroxide (120 g/1), whereby colloid of zinc hydroxide was formed, and the colloid formed was added to, and fixed on, the NBSP fibers to produce deodorizing fibers.
The fibers were shaped into a sheet by using a sheet machine and then dried to give a sheet of ca. 410 g/m 2 .
Then, the quantity of zinc hydroxide fixed on the sheet was determined (in W/W% reduced to zinc and based on the weight of the NBSP), and the rate(%) of zinc fixed, based on the weight of zinc added, was calculated therefrom. Results obtained are also shown in Table 2.
Thereafter, the deodorizing capability for H 2 S gas and NH 3 gas of the product according to Examples 10-11 was evaluated in accordance with the test method described hereinbefore.
Fixed quantity: 4.9% by weight
Fixed rate: 79%
Deodorizing capability:
______________________________________Immediately After After Afterafter sealing 10 min. 30 min. 60 min.______________________________________H.sub.2 S 29 2 0NH.sub.3 19 5 0______________________________________
EXAMPLE 14
To 20 liters of an alkaline solution whose pH had been adjusted to 9.5 by the addition of sodium hydroxide was added 1,000 g of NBSP, and the mixture was disaggregated to a slurry by using a disaggregator. Subsequently, an aqueous copper sulfate solution containing 200 g/l of CuSO 4 .5H 2 )0 was added thereto up to an amount of copper of 2% by weight, based on the weight of NBSP. Then, the pH of the mixture was adjusted to 8 by using an aqueous solution of sodium hydroxide (120 g/l), whereby colloid of copper hydroxide was formed, and the colloid formed was attached to, and fixed on, the NBSP to produce deodorizing fibers. The fibers were shaped into a sheet by using a sheet machine and then dried to give a sheet of 410 g/m 2 .
The quantity of copper hydroxide fixed on the sheet was determined (in W/W% reduced to copper and based on the weight of the NBSP), and the rate(%) of copper fixed, based on the weight of zinc added, was calculated therefrom. Results obtained are also shown in Table 2.
Comparative Examples 1-2
To 20 liters of water was added 1,000 g of NBSP (cellulose fiber), and the mixture was disaggregated to a slurry by using a disaggregator. Subsequently, a 4 W/W% dispersion of commercially available copper hydroxide powders was added to the slurry of pulp up to a weight ratio of NBSP/Cu=98/2 or 94/4 (Comparative Example 1 or 2, respectively). After being stirred for 30 minutes, each of the mixtures was shaped into a sheet by using a sheet machine and then dried to give a sheet of ca. 410 g/m 2 .
Copper hydroxide was not fixed well on any of the sheets, and powders of copper hydroxide dropped off when the sheets were rubbed with a finger.
Comparative Examples 3-4
To 20 liters of water was added 1,000 g of NBSP (cellulose fiber), and the mixture was disaggregated to a slurry by using a disaggregator. Subsequently, a 4 W/W% dispersion of commercially available zinc hydroxide powders was added to the slurry of pulp up to a weight ratio of NBSP/Zn=98/2 or 94/4 (Comparative Example 3 or 4, respectively). After being stirred for 30 minutes, each of the mixtures was shaped in a sheet by using a sheet machine and then dried to give a sheet of 410 g/m 2 .
Zinc hydroxide was not fixed well on any of the sheets, and powders of copper hydroxide dropped off when the sheets were rubbed with a finger.
EXAMPLE 15
1,000 g of NDSP (used as a cellulose fiber) was added to 20 liters of water, disaggregated to the state of slurry by using a disaggregator and then subjected to an acid treatment by the addition of an aqueous SO 2 solution up to a pH of 3.3. Subsequently, an aqueous copper chloride solution (CuCl 2 .2H 2 O) was added thereto up to a concentration of 6 W/W% (reduced to copper and based on the weight of the NDSP). Then, the pH of the mixture was adjusted to 8 by the addition of an aqueous solution of sodium hydroxide (120 g/l), whereby colloid of copper hydroxide was formed, and the colloid formed was attached to, and fixed on, the NDSP fibers to produce deodorizing fibers.
The fibers were then shaped into a sheet by using a sheet machine and then dried to give a sheet of ca. 410 g/m 2 .
The quantity of copper hydroxide fixed on the sheet was determined (in W/W% reduced to copper and based on the weight of the NDSP), and the rate(%) of copper fixed thereon, based on the weight of copper added, was calculated therefrom. Results obtained are also shown in Table 2.
Thereafter, the deodorizing capability for H 2 S gas and NH 3 gas of the sheet was evaluated in accordance with the test method described hereinbefore. Results obtained are shown in Table 2.
It would be apparent from the results shown in Table 2 that the object of the present invention can also be attained in the case where copper chloride is used for the formation of copper hydroxide colloid.
EXAMPLE 16
1,000 g of cotton wool (used as a cellulose fiber) was added to 20 liters of water, disaggregated to the state of slurry by using a disaggregator and then subjected to an acid treatment by the addition of an aqueous SO 2 solution up to a pH of 3.3. Subsequently, an aqueous copper sulfate solution containing 200 g/l of CuSO 4 .5H 2 O was added thereto up to a concentration of 4 W/W% (reduced to copper and based on the weight of the cotton wool). Thereafter, the pH of the mixture was adjusted to 8 by the addition of an aqueous solution of sodium hydroxide (120 g/l), whereby colloid of copper hydroxide was formed, and the colloid formed was attached to, and fixed on, the cotton wool to give deodorizing fibers.
The thus obtained dispersion was shaped into a sheet by using a sheet machine and then dried to give a sheet of ca. 410 g/m 2 .
The quantity of copper hydroxide fixed on the sheet was determined (in W/W% reduced to copper and based on the weight of the cotton wool), and the rate(%) of copper fixed thereon, based on the weight of copper added, was calculated therefrom. Results obtained are also shown in Table 2.
Thereafter, the deodorizing capability for H 2 S gas and NH 3 gas of the sheet was evaluated in accordance with the test method described hereinbefore. Results obtained are shown in Table 2.
It would be apparent from the results shown in Table 2 that the object of the present invention can also be attained by using cotton wool.
EXAMPLE 17
1,000 g of rayon (used as a cellulose fiber) was added to 20 liters of water, disaggregated to the state of slurry by using a disaggregator and then subjected to an acid treatment by the addition of an aqueous SO 2 solution up to a pH of 3.3. Subsequently, an aqueous copper sulfate solution containing 200 g/l of CuSO 4 .5H 2 O was added thereto up to a concentration of 4 W/W% (reduced to copper and based on the weight of the rayon). Thereafter, the pH of the mixture was adjusted to 8 by the addition of an aqueous solution of sodium hydroxide (120 g/l), whereby colloid of copper hydroxide was formed, and the colloid formed was attached to, and fixed on, the rayon fibers to give deodorizing fibers.
The fibers obtained were shaped into a sheet by using a sheet machine and then dried to give a sheet of ca. 410 g/m 2 .
The quantity of copper hydroxide fixed on the sheet was determined (in W/W% reduced to copper and based on the weight of the rayon) and the rate(%) of copper fixed, based on the weight of the copper added, was calculated therefrom. Results obtained are also shown in Table 2.
Thereafter, deodorizing capability for H 2 S gas and NH 3 gas of the sheet was evaluated in accordance with the test method described hereinbefore Results obtained are shown in Table 2.
It would be apparent from the results shown in Table 2 that the objects of the present invention can also be attained by using rayon.
EXAMPLE 18
100 g of NBKP (used as a cellulose fiber) was dipped in 300 g of water and then ground by a grinder.
Subsequently, an aqueous SO 2 solution was added thereto up to a pH of 3, and after being stirred further, an aqueous copper sulfate solution containing 200 g/l of CuSO 4 .5H 2 O was added thereto up to a concentration of 4 W/W% (reduced to copper and based on the weight of the NBKP). Thereafter, an aqueous solution of sodium hydroxide (120 g/l was added up to a pH of 8, and the mixture was stirred further to prepare a dispersion. In a separate operation, a dispersion was prepared by disaggregating untreated NBKP to the state of slurry, and then admixed with the dispersion prepared above at a ratio of 1:1, based on the weight of solids. The resulting product was shaped into a sheet by using a sheet machine and dried to give a sheet of ca. 410 g/m 2 .
The deodorizing capability for H 2 S gas and NH gas of the sheet was evaluated in accordance with the test method described hereinbefore. Results obtained are shown in Table 2.
EXAMPLE 19
A sheet was prepared in the same manner as in Example 16, and 5 g of the sheet was dipped with stirring in 50 ml of diluted aqueous ammonia solution (concentration: 2,000 ppm). After it had been allowed to stand for 1 hour, it was tried to smell the odor of ammonia of the aqueous solution, but no ammonia odor was detected.
EXAMPLE 20
A sheet was prepared in the same manner as in Example 16, and 5 g of the sheet was dipped with stirring in 50 ml of diluted aqueous H 2 S solution (concentration: 4,000 ppm). After it had been allowed to stand for 1 hour, it was tried to smell the odor of H 2 S, but no H 2 S odor was detected.
EXAMPLE 21
1,000 g of cotton wool (cellulose fiber) was added to 20 liters of water and disaggregated to the state of slurry by using a disaggregator, and then an aqueous SO 2 solution was added thereto up to a pH of 3.0. Subsequently, an aqueous solution of zinc chloride (200 g/l) was added thereto up to a concentration of 4 W/W% (reduced to zinc and based on the weight of the cotton wool). The pH of the mixture was adjusted to 8 by the addition of an aqueous solution of sodium hydroxide (120 g/l), whereby colloid of zinc hydroxide was formed, and the colloid formed was attached to, and fixed on, the cotton wool to produce deodorizing fibers. The fibers obtained were shaped into a sheet by using a sheet machine and dried to give a sheet of ca. 410 g/m 2 .
The quantity of zinc hydroxide fixed was 3.2 W/W% (reduced to zinc and based on the weight of the cotton wool), and the rate(%) of zinc fixed was 80 W/W%, based on the weight of zinc added.
5 g of the sheet was dipped with stirring in 50 ml of diluted aqueous ammonia solution (concentration: 2,000 ppm). After it had been allowed to stand for 1 hour, it was tried to smell the odor of ammonia of the aqueous solution, but no ammonia odor was detected.
EXAMPLE 22
1,000 g of rayon (cellulose fiber) was added to 20 liters of water and disaggregated to the state of slurry by using a disaggregator, and then an aqueous SO 2 solution was added thereto up to a pH of 3.0. Subsequently, an aqueous solution of zinc chloride (200 g/l) was added thereto up to a concentration of 4 W/W% (reduced to zinc and based on the weight of the rayon).
Then, an aqueous solution of sodium hydroxide (120 g/l) was added thereto to adjust its pH to 8, whereby colloid of zinc hydroxide was formed, and the colloid formed was attached to, and fixed on, the rayon fibers to produce deodorizing fibers.
The fibers obtained were shaped into a sheet by using a sheet machine and dried to give a sheet of ca. 410 g/m 2 .
The quantity of zinc fixed was 2.8 W/W% (reduced to zinc and based on the weight of rayon), and the rate(%) of zinc fixed was 70 W/W%, based on the weight of zinc added.
5 g of the sheet was dipped with stirring in 50 ml of diluted aqueous H 2 S solution (concentration: 4,000 ppm). After it had been allowed to stand for 1 hour, it was tried to smell the odor of H 2 S of the aqueous solution, but no H 2 S odor was detected.
Copper hydroxide and/or zinc hydroxide can be fixed on cellulose fibers by attaching copper hydroxide and/or zinc hydroxide in a colloidal state onto cellulose fibers in accordance with the process of the present invention. Copper hydroxide and/or zinc hydroxide so fixed are capable of acting on, and exhibiting excellent deodorizing capability for, malodorous gaseous substances, such as hydrogen sulfide, ammonia, methyl mercaptan, etc., in particular, ammonia and hydrogen sulfide, or for ammonia, hydrogen sulfide, etc. dissolved in water.
The deodorizing fibers can be an excellent deodorizer as they are. The fibers, since they are in fibrous form, are also excellent in their processability and can be shaped into a product of any desired shape, including sheets or the like. They are therefore usable as a deodorizing material and can be applied to various uses in the field of deodorization.
TABLE 1______________________________________ Amount Fixed Fixed Rate pH (W/W %) (%)______________________________________Example 1 5.0 0.2 7Example 2 6.0 2.0 67Example 3 9.5 2.5 83Example 4 6.5 0.2 7Example 5 8.0 1.8 60Example 6 9.5 2.3 77______________________________________
TABLE 2__________________________________________________________________________Cu or Zn components H.sub.2 S Gas NH.sub.3 Gas Amount Fixed Immediately Time Lapsed Immediately Time LapsedAmount Fixed Rate After 10 30 60 After 10 30 60Added (W/W %) (%) Start Min. Min. Min. Start Min. Min. Min.__________________________________________________________________________Example 7 0.05 0.05 80 62 35 15 0 22 21 12 10Example 8 0.5 0.4 80 45 4 0 20 12 8 3Example 9 2 1.8 90 12 3 0 10 1 0Example 10 2 1.5 75 22 6 0 20 10 5 5Example 11 6 3.8 63 30 2 0 21 7 2 1 Cu 2 Cu 1.8 90Example 12 Zn 2 Zn 1.3 65 30 2 0 19 7 0Example 13 4 4.9 79 29 2 0 19 5 0 9Example 14 2 1.9 95 31 8 0 30 12 10 11Example 15 6 3.8 63 28 2 0 20 8 0Example 16 4 2.9 72 10 0 60 35 20 35Example 17 4 2.7 68 6 0 21 17 7 9Example 18 4 2.7 68 31 3 0 60 28 10 21__________________________________________________________________________
TABLE 3__________________________________________________________________________Cu Component Methyl Mercaptan Gas Amount Fixed Immediately Time LapsedAmount Fixed Rate After 10 30 60Added (W/W %) (%) Start Min. Min. Min.__________________________________________________________________________Example 7 0.05 0.04 80 30 26 20 10Example 8 0.5 0.4 80 25 25 15 10Example 9 2 1.8 90 10 5 5 5__________________________________________________________________________
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This invention is concerned with a process for producing deodorizing cellulose fibers on which a considerable amount of copper hydroxide and/or zinc hydroxide is fixed highly strongly, which process is characterized in that cellulose fibers are allowed to contact with a colloidal solution of copper hydroxide and/or zinc hydroxide prepared by adding an alkaline substance to an aqueous solution of a water-soluble copper compound and/or a water-soluble zinc compound. Deodorizing fibers so obtained are capable of effectively removing malodorous gaseous substances, such as hydrogen sulfide, ammonia, methyl mercaptan, etc., and exhibit excellent deodorizing effects. In addition, the deodorizing fibers, although they can be an excellent deodorizing material as they are, are excellent in workability and hence can be used in the form of a shaped product, including, e.g., granules, sheets, etc. They can therefore be applied to various uses in the field of deordorization.
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BACKGROUND
[0001] The popular functionalities of information handling devices (“devices”), for example smart phones, tablets, e-readers, etc., are being converted into wearable formats. An example of such a wearable information handling device is a smart watch such as the Samsung GALAXY GEAR smart watch. GALAXY GEAR is a registered trademark of Samsung Electronics Co., Ltd. in the United States and/or other countries. Other examples of wearable information handling devices include bracelets, sleeves, gloves, and like articles that, while wearable by a user, provide electronic or computing functionality similar to smart phones and other mobile computing devices.
BRIEF SUMMARY
[0002] In summary, one aspect provides a wearable information handling device, comprising: a display; a band; one or more processors operatively coupled to the display; and a memory device accessible to the one or more processors and storing code executable by the one or more processors to: after identifying information to be communicated, form an output directed to the band of the wearable information handling device; and provide the output to the band; the output actuating one or more elements of the band.
[0003] Another aspect provides a method, comprising: identifying information to be communicated; after identifying information to be communicated, forming an output directed to a band of a wearable information handling device; and providing the output to the band; the output actuating one or more elements of the band.
[0004] A further aspect provides a wearable information handling device, comprising: a band; one or more processors; and a memory device accessible to the one or more processors and storing code executable by the one or more processors to: after identifying information to be communicated, form an output directed to the band of the wearable information handling device; and provide the output to the band; the output actuating one or more elements of the band.
[0005] The foregoing is a summary and thus may contain simplifications, generalizations, and omissions of detail; consequently, those skilled in the art will appreciate that the summary is illustrative only and is not intended to be in any way limiting.
[0006] For a better understanding of the embodiments, together with other and further features and advantages thereof, reference is made to the following description, taken in conjunction with the accompanying drawings. The scope of the invention will be pointed out in the appended claims.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0007] FIG. 1 illustrates an example of information handling device circuitry.
[0008] FIG. 2 illustrates an example wearable information handling device.
[0009] FIG. 3 illustrates an example method of providing output(s) with a wearable information handling device.
DETAILED DESCRIPTION
[0010] It will be readily understood that the components of the embodiments, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations in addition to the described example embodiments. Thus, the following more detailed description of the example embodiments, as represented in the figures, is not intended to limit the scope of the embodiments, as claimed, but is merely representative of example embodiments.
[0011] Reference throughout this specification to “one embodiment” or “an embodiment” (or the like) means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” or the like in various places throughout this specification are not necessarily all referring to the same embodiment.
[0012] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that the various embodiments can be practiced without one or more of the specific details, or with other methods, components, materials, et cetera. In other instances, well known structures, materials, or operations are not shown or described in detail to avoid obfuscation.
[0013] Wearable information handling devices such as smart watches are an upcoming form-factor in mobile computing. With necessarily smaller screens, smart watches need more output methods if they are to fulfill their potential as always-on companion devices.
[0014] A primary output device of conventional wearable information handling devices (also referred to herein as “devices” or “information handling devices”), e.g., a smart watch, is a screen of varying capability. Since these devices are small, battery space is at a premium and power consumption is a concern. A way to alleviate the power concerns encountered by such devices is by reducing the capability of the screen, e.g., by moving to an e-ink or similar solution instead of using other screen technologies (e.g., LCD or the like). Smart watches also typically have vibrating motors (e.g., actuators) to alert the user, as well as speakers. Both of these output methods are bandwidth-limited, as the vibrating motor cannot easily convey complex information and the speaker may not be appropriate for all situations.
[0015] Accordingly, an embodiment provides a wearable information handling device such as a smart watch with a band portion having output communication capabilities. In an embodiment, the band portion includes elements that have the ability to squeeze the user's wrist. Thus, an embodiment includes band element(s) as another method of output.
[0016] The illustrated example embodiments will be best understood by reference to the figures. The following description is intended only by way of example, and simply illustrates certain example embodiments.
[0017] Referring to FIG. 1 , while various other circuits, circuitry or components may be utilized in information handling devices, with regard to a wearable information handling device's circuitry, for example a smart watch or bracelet, an example illustrated in FIG. 1 includes a system on a chip design 100 found for example in tablet or other small, mobile computing platforms. Software and processor(s) are combined in a single chip 110 . Internal busses and the like depend on different vendors, but essentially all the peripheral devices ( 120 ) such as a microphone may attach to a single chip 110 . The circuitry 100 combines the processor, memory control, and I/O controller hub all into a single chip 110 . Also, systems 100 of this type do not typically use SATA or PCI or LPC. Common interfaces for example include SDIO and I2C.
[0018] There are power management chip(s) 130 , e.g., a battery management unit, BMU, which manage power as supplied for example via a rechargeable battery 140 , which may be recharged by a connection to a power source (not shown). In at least one design, a single chip, such as 110 , is used to supply BIOS like functionality and DRAM memory.
[0019] System 100 typically includes one or more of a WWAN transceiver 150 and a WLAN transceiver 160 for connecting to various networks, such as telecommunications networks and wireless base stations. Commonly, system 100 will include a touch screen 170 for data input and display. System 100 also typically includes various memory devices, for example flash memory 180 and SDRAM 190 . As is apparent from the description herein, embodiments may include other features or only some of the features of the example illustrated in FIG. 1 .
[0020] Information handling device circuitry and components, as for example outlined in FIG. 1 , may be included in a wearable form factor such as a smart watch. An example is illustrated in FIG. 2 . In the illustration of FIG. 2 , the system or device 200 includes a band portion and one or more elements 202 in or about (e.g., attached to) the band portion. Other components, e.g., processor, touch screen display, standard display, etc., may be included but are omitted from FIG. 2 for ease of illustration.
[0021] In one embodiment, a band 201 squeezes at a single point, e.g., using one of the elements 202 , to communicate (e.g., indicate a notification). Optionally, in concert with other low-bandwidth output channels, e.g., audio and/or haptic actuator(s), a more dense output message can be created without requiring the user to look at a screen or invoking a speaker with some form of natural language output directed to the user. The band 201 may squeeze at variable degrees, e.g., harder or pulse faster/repeatedly, as a form of coded communication. For example, if the band element(s) 201 were communicating output in combination with a navigation system, as the user closes in on a navigation destination, harder and/or more frequent squeezing of the band 201 via element(s) 202 may take place to catch the user's attention and alert him/her of the approaching destination.
[0022] Additionally or in the alternative, an embodiment squeezes the band 201 in different segments, as for example actuating elements 202 that are separated spatially.
[0023] This, alone or in combination with the timing of element 202 actuation, may again be used to provide a more rich output than has previously been achievable using such low-bandwidth output channels.
[0024] For example, this allows a form of crude numerical or other pattern output. For instance, the user may verbally ask “when is my next meeting?” and the watch responds with output in the form of squeezing three of its segments 202 , e.g., via actuation of elements 202 , to indicate that the meeting is at 3 o'clock. If the number individual pulses are hard to pick out, e.g., in the case of using only one element 202 , the outputs may be differentiated, e.g., spatially and/or in time. For example, an embodiment may actuate elements in an offset fashion such that element actuation is slightly offset in time to make the outputs more easily perceivable/distinguishable.
[0025] In an embodiment, given the desired level of communication, a smart watch or other wearable device may be formed and communicate acceptably with a user without utilizing a screen (e.g., a screen-less smart watch). For example, according to an embodiment, a smart watch may take inputs (e.g., commands) verbally or by some other input modality (e.g., via hand action such as touch or gesture input) and respond with band portion actuation, alone or in combination with one or more other output channels, e.g., buzzing/haptics, audio, etc.
[0026] The squeezing of the band 201 may take place by reducing the size of the band (e.g., reducing its internal circumference) such that it squeezes a user wearing the band. The squeezing of the band 201 may take a variety of forms. For example, the squeezing of the band 201 may be implemented by swelling or enlarging the element(s) 202 . The swelling in the band 201 may be provided mechanically, thermally or chemically. For example, a thermally swelled element may be provided by vaporizing some material with electrical current such that a phase change (e.g., liquid to gas) occurs and inflates a flexible/inflatable element 202 . Additionally or in the alternative, a mechanically swelled element may be implemented using a flapper or displaceable element(s) that is/are erected, e.g., via a circular gear traversing the span of the band. Small actuators may be implemented to select which flapper(s) or displaceable element(s) that the gear acts on. One or more elements of the band may be actuated to change the overall size of the band in alternative or additional ways. For example, a band may include or consist of a material such as muscle wire, e.g., Nitinol or nickel/titanium, where the material undergoes a reversible or controllable conformational change responsive to an event, e.g., provisioning of electrical stimulant.
[0027] Referring to FIG. 3 , an example method of providing output(s) with a wearable information handling device is illustrated. In an example use context, a wearable information handling device, e.g., a smart watch 200 such as outlined in the example of FIG. 2 , may monitor for information that is to be communicated to the user. Examples of information that may be/is to be communicated to the user include a notification of an incoming message (e.g., email, text, etc.), a response to an input of the user (e.g., response to a verbal query by the user, etc.) or the like. If information is identified that is to be communicated to the user at 310 , e.g., an answer to a query, a message notification, etc., an embodiment may convert the information into an output at 320 . The output may include a plurality of outputs.
[0028] For example, an embodiment may identify an answer to a query at 310 as information to be communicated to the user. Thus, if a user queries “what time is my next meeting?”, an embodiment may identify information to be communicated to the user at 310 as information indicating that the next meeting is at 3:00 p.m. (e.g., via consulting a calendar application). Therefore, an embodiment may convert this information into a format suitable for use as output at 320 . In one example, the information may be converted to output by translating or converting the information into command(s) to elements 202 of the band 201 , e.g., actuating the appropriate elements 202 .
[0029] The output may then be provided to the element(s) of the band portion at 330 . In the example given herein, this may comprise actuating band element(s) (e.g., mechanically, thermally, etc.) to communicate that the next meeting of the user is at 3:00 p.m. This may take a variety of forms, as described herein. For example, the outputs may actuate the elements of the band portion at 340 simultaneously (or nearly so), at different times (e.g., spaced in time), or a combination of the foregoing. Thus, the device may use a squeezing of the band, which may take a variety of forms including but not necessarily limited to swelling of element(s) of the band portion, to provide an additional output channel or modality for a wearable device.
[0030] This permits the wearable device to leverage an additional output mechanism that may be used alone or in combination with other output mechanisms in order to communicate with the user. As described herein, the permits new modes of output to be realized and results in reducing the power necessary to communicate effectively with the wearer of the device.
[0031] As will be appreciated by one skilled in the art, various aspects may be embodied as a system, method or device program product. Accordingly, aspects may take the form of an entirely hardware embodiment or an embodiment including software that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, aspects may take the form of a device program product embodied in one or more device readable medium(s) having device readable program code embodied therewith.
[0032] Any combination of one or more non-signal device readable medium(s) may be utilized. The non-signal medium may be a storage medium. A storage medium may be, for example, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of a storage medium would include the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a storage medium is not a signal and “non-transitory” includes all media except signal media.
[0033] Program code embodied on a storage medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, et cetera, or any suitable combination of the foregoing.
[0034] Program code for carrying out operations may be written in any combination of one or more programming languages. The program code may execute entirely on a single device, partly on a single device, as a stand-alone software package, partly on single device and partly on another device, or entirely on the other device. In some cases, the devices may be connected through any type of connection or network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made through other devices (for example, through the Internet using an Internet Service Provider) or through a hard wire connection, such as over a USB connection.
[0035] Aspects are described herein with reference to the figures, which illustrate example methods, devices and program products according to various example embodiments. It will be understood that the actions and functionality may be implemented at least in part by program instructions. These program instructions may be provided to a processor of a general purpose information handling device, a special purpose information handling device, or other programmable data processing device or information handling device to produce a machine, such that the instructions, which execute via a processor of the device implement the functions/acts specified.
[0036] This disclosure has been presented for purposes of illustration and description but is not intended to be exhaustive or limiting. Many modifications and variations will be apparent to those of ordinary skill in the art. The example embodiments were chosen and described in order to explain principles and practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.
[0037] Thus, although illustrative example embodiments have been described herein with reference to the accompanying figures, it is to be understood that this description is not limiting and that various other changes and modifications may be affected therein by one skilled in the art without departing from the scope or spirit of the disclosure.
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An aspect provides a wearable information handling device, including: a display; a band; one or more processors operatively coupled to the display; and a memory device accessible to the one or more processors and storing code executable by the one or more processors to: after identifying information to be communicated, form an output directed to the band of the wearable information handling device; and provide the output to the band; the output actuating one or more elements of the band. Other aspects are described and claimed.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a Continuation-In-Part of International Patent Application No. PCT/US2008/069706 filed on Jul. 10, 2008, which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
The present invention relates to adhesive and non-adhesive articles and methods of making the same. More particularly, the articles, or films, described herein do not contain polyvinyl chloride (“PVC”). The articles can be used in a variety of applications, including for example, signs, graphics, wall covering, pressure sensitive products, and the like.
BACKGROUND OF THE INVENTION
Vinyl films plasticized with plasticizers have been used for many years in adhesive labels, tapes and decorative sheets. Vinyl films, particularly polyvinyl chloride (PVC) films, have had wide acceptance for such applications because, among other things, they are inexpensive and weather resistant and can be colored easily with pigments and dyes. In addition, plasticized polyvinyl chloride (PVC) has had particularly wide acceptance because its properties can be modified over a wide range by the incorporation of plasticizers. These films have been used in various graphic applications with success.
Although vinyl films have been useful in graphic and wall covering applications because of their superior flexibility and conformability, there is a continuing need to develop films which do not contain PVC. The halogen-containing materials such as PVC have generally been recognized as producing undesirable by-products when burned.
Accordingly, there is a need for environmentally friendly, non-PVC films that have properties that are comparable with PVC films. The present invention satisfies this need.
SUMMARY OF THE INVENTION
The present invention includes various compositions, films made from the compositions, film laminates and related methods. An exemplary embodiment is a composition that is configured for use in creating films. The composition includes vinyl acetate containing polymer and at least one additive that is a pigment, a surfactant, a dispersant, a wetting agent, a plasticizer, a defoamer, a coupling agent, a solvent, a UV absorber, a fire retardant, or a light stabilizer. A vinyl acetate containing polymer refers to vinyl acetate copolymer or homopolymer or the mixture of the two. An exemplary vinyl acetate copolymer is Vinyl Acetate Ethylene (VAE) Copolymer. The Vinyl Acetate Ethylene (VAE) Copolymer is a product based on the copolymerization of vinyl acetate and ethylene in which the vinyl acetate content can range between 60-95%, and the ethylene content ranges between 5-40% of the total formulation. This product should not be confused with the ethylene vinyl acetate (EVA) copolymers in which the vinyl acetate generally range in composition from 10-40%, and ethylene can vary between 60-90% of the formulation. VAEs are water-based emulsions, whereas EVAs are solid materials used for hot melt and plastic molding applications. VAEs are also sold in powder form, a technology pioneered in Europe.
Another exemplary embodiment of the invention includes composition comprising: an acrylic copolymer, a VAE copolymer, and additives, e.g., titanium dioxide, surfactant, dispersant, wetting agent, or defoamer. Another exemplary embodiment of the invention includes composition comprising: a hybrid of an acrylic and a VAE copolymer, and additives, e.g., titanium dioxide, surfactant, dispersant, wetting agent, or defoamer. A hybrid of an acrylic and a VAE copolymer refers to a polymer product made by seeded emulsion polymerization where an acrylic monomer is polymerized in the presence of VAE copolymer emulsion as seed latex. Another exemplary embodiment of the invention includes composition comprising: an acrylic copolymer, titanium dioxide, and additives, e.g., surfactant, dispersant, a wetting agent or defoamer. Another exemplary embodiment includes polyurethane, a blend of polyurethane and VAE copolymer, a polyurethane acrylic copolymer, a blend of polyurethane and acrylic copolymer.
In another embodiment, latex or CaCO 3 (calcium carbonate) can be used instead of titanium dioxide thereby making the film with same or similar opacity, but reducing the cost of the film. In one embodiment, the composition is a liquid formulation. In another embodiment, the composition is an emulsion.
Another exemplary embodiment is a film including a vinyl acetate containing polymer and at least one additive that is a pigment, a surfactant, a dispersant, a wetting agent, a plasticizer, a defoamer, a coupling agent, a solvent, a UV absorber, a fire retardant, or a light stabilizer. The film has an elongation of at least about 50%.
Another exemplary embodiment is a film including an acrylic copolymer, VAE, titanium dioxide, and at least one additive that is a surfactant, a dispersant, a wetting agent, or a defoamer.
Another exemplary embodiment is a film that includes a liner, a pressure sensitive adhesive, a strengthening layer, and a print receptive layer. The print receptive layer includes a material that is an emulsion of a blend of vinyl acetate with VAE, a VAE/acrylic hybrid, a VAE copolymer, or an acrylic formulation. In a further embodiment, the film is a graphics film.
Another exemplary embodiment is an assembly that includes a liner, a pressure sensitive adhesive, and a strengthening layer that includes a material that is a blend of cross linkable vinyl acetate copolymer with a VAE emulsion, or a polyurethane emulsion, or a blend of polyurethane containing emulsions.
One exemplary method of making the film of the present invention includes the steps of: making a composition comprising polyvinyl acetate homopolymer or copolymer, titanium dioxide, and additives; and applying the composition as a coat over a liner. The coated liner is then dried and the film peeled from the liner. In another exemplary embodiment of making the film, the composition is cast onto a polyethylene terephthalate (“PET”) film.
Another exemplary method according to the invention is a method of making a film. The method includes providing components and a substrate, blending the components to form a composition, and coating the substrate with the composition. The composition includes a vinyl acetate containing polymer, and at least one additive that is a pigment, a surfactant, a dispersant, a wetting agent, a plasticizer, a defoamer, a coupling agent, a solvent, a UV absorber, a fire retardant, or a light stabilizer. In other, more detailed features of the invention, the method further includes drying the composition, and removing the dried composition from the substrate. According to a further aspect of the invention, the substrate can be a polyethylene terephthalate film.
The films of the present invention when tested for tensile strength and tensile elongation, printability by direct printing (non-impact printing) on the film specimen using solvent-based ink-jet printer, and durability in accordance with the procedures of SAE Technical Standard J1960 (Rev. October 2004) exhibit at least one of the following physical properties: tensile elongation at break of at least 100%, good printing without smudges and diffusion of ink as determined by visual inspection, and durability of 1 month to 7 years.
The non-PVC films of the present invention are weather resistant and can be colored easily with pigments and dyes. In addition, opacity can be modified by adding appropriate amount of pigments. These pigments can be included as a layer, or layers, in the film. Also, a white or gray ink wash can be used to improve the opacity of the film. The non-PVC films can be used in the manufacture of both pressure sensitive adhesive products and non-adhesive sheets and films, which include labels, tapes, banners, signage, vehicle wraps, advertising panels, and decorative sheets, and for a variety of other applications, including but not limited to applications where PVC films are generally used.
Other features of the invention should become apparent to those skilled in the art from the following description of the preferred embodiments taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention, the invention not being limited to any particular preferred embodiment(s) disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
These, as well as other features, aspects, and advantages of this invention, will be more completely understood and appreciated by referring to the following more detailed description of the presently preferred exemplary embodiments of the invention in conjunction with the accompanying drawings, of which:
FIG. 1 is a sectional view of a film prepared in accordance with an exemplary embodiment of the present invention.
FIG. 2 is a flow diagram of a method of making a film in accordance with the present invention.
Unless otherwise indicated, the illustrations in the above figures are not necessarily drawn to scale.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is now illustrated in greater detail by way of the following detailed description that 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.
The invention relates to composition and manufacture of polyvinyl chloride (“PVC”) replacement films. The films of the present invention do not contain PVC and hence are called non-PVC films. The non-PVC films offer the advantage of being environmentally friendly and having the property of conformability, durability, or printability of PVC films. The non-PVC films of the present invention have properties and performance that are comparable to, or exceed, those of the PVC films, and are suitable for applications where PVC films are generally used, including for example, signs, graphics, wall covering, pressure sensitive products and the like.
FIG. 1 is a sectional view of an exemplary film prepared in accordance with the present invention. The film is generally depicted by reference to numeral 5 and includes a release liner 10 , such as a silicone coated material, a pressure sensitive adhesive layer 20 , a strengthening layer 30 , and a print layer 40 .
The adhesive layer 20 generally can be classified into the following categories: random copolymer adhesives such as those based upon acrylate and/or methacrylate copolymers, α-olefin copolymers, silicone copolymers, chloroprene/acrylonitrile copolymers, and the like; and block copolymer adhesives including those based upon linear block copolymers (i.e., A-B and A-B-A type), branched block copolymers, star block copolymers, grafted or radial block copolymers, and the like, and natural and synthetic rubber adhesives.
A description of useful pressure-sensitive adhesives can be found in Encyclopedia of Polymer Science and Engineering, Vol. 13. Wiley-Interscience Publishers (New York, 1988). Additional descriptions of useful pressure-sensitive adhesives can be found in Encyclopedia of Polymer Science and Technology, Vol. 1, Interscience Publishers (New York, 1964).
The liner 10 is preferably an ultrathin or ultra light liner having a thickness of less than 1.02 mil (0.0255 mm), less than 1 mil (0.0254 mm), less than 0.8 mil (0.0203 mm), less than 0.6 mil (0.015 mm), less than 0.50 mil (0.013 mm), or equal to or less than 0.25 mil (0.00626 mm). Such thin liners are commercially available as HOSTAPHAN® polyester film (e.g., 0.5 mil, 0.0127 mm, Tradename 2SLK silicone coated film) sheeting from Mitsubishi Chemical Company of Tokyo Japan. Another liner material is provided by Avery Dennison Corporation of Pasadena, Calif. as a 1.02 mil (0.026 mm) polyester backing sheet with a 1.25 mil (0.032 mm) adhesive layer.
The strengthening layer 30 can include a blend of cross linkable vinyl acetate copolymer and VAE emulsions, or it can be a polyurethane containing emulsions. The print layer 40 can include in exemplary embodiments a vinyl acetate containing polymer, a blend of vinyl acetate with VAE, a VAE/acrylic hybrid, an all acrylic formulation, or a VAE emulsion.
The exemplary embodiments of composition and film 5 of the present invention include at least one of the following:
(1) Vinyl acetate ethylene (“VAE”), (2) VAE-acrylic hybrid (3) Vinyl acetate homopolymer, (4) Blend of VAE and vinyl acetate homopolymer, (5) Blend of VAE and vinyl acetate copolymer, (6) Blend of VAE with polyurethane, (7) Blend of VAE with acrylic copolymer, (8) Cross linking of VAE by adding small content of silane, (9) Acrylic copolymer (10) Polyurethane containing polymer, and/or (11) Blend of Polyurethane and acrylic
In other embodiments, a pigment, e.g., Titanium dioxide (“TiO 2 ”) and/or other pigments, can be added to any of the above ten embodiments of composition and film of the present invention. The opacity of the film 5 depends on the amount of TiO 2 or other materials. In another embodiment, the pigment, e.g., TiO 2 , can be replaced with latex such as ROPAQUE OP-96 or ULTRA-OPAQUE, made by Rohm and Haas of Philadelphia, Pa. In another embodiment, pigment like TiO 2 may not be included if a clear film is desired. In a further embodiment, CYMEL 385 by Cytec Industries Inc. of West Paterson, N.J. can be used as a cross-linker to increase the tensile strength of the film. In another embodiment used for nonprinting applications, wax emulsion, e.g., MICHEM GUARD 55 from Michelman of Cincinnati, Ohio, can be added to any of the above ten embodiments of composition and film, thereby providing the property of ease-of-cleaning to the film. In yet another embodiment, wax emulsion, e.g., MICHEM EMULSION 47950 from Michelman can be added to any of the above ten embodiments of composition and film of the present invention, and the manufactured film can be useful for anti-graffiti applications. The present invention further includes a method of making the film.
In other embodiments, the carboxyl containing components of the print layer are crosslinkable using polyaziridine, for example, XAMA-7 from Lubrizol. The hydroxy containing components are crosslinkable using polyaziridine or melamine formaldehyde, e.g. CYMEL 385 from Cytec Industries Inc. Other crosslinkers known to the skilled in the art can also be used to cross link the print layer components.
The film 5 of the present invention can be formed by preparing a liquid formulation or emulsion of an embodiment of composition of the present invention and then coating, such as by curtain coating, a substrate with the formulation or emulsion. In one embodiment, the substrate is a liner. In another embodiment, the substrate is a polyethylene terephthalate (“PET”) film.
An exemplary method of making a film according to the present invention is illustrated in the flowchart 50 of FIG. 2 . After starting at step 60 , the next step 70 is to provide components and a substrate. Next, at step 80 , the components are blended to form a composition. The composition includes a vinyl acetate containing polymer and at least one additive. Next, at step 90 , the substrate is coated with the composition. At step 100 , the composition is dried, and then, at step 110 , the dried composition is removed from the substrate. The method ends at step 120 .
In another embodiment of the film 5 of the invention, a blend of polyvinyl acetate (“PVA”) and surfactant protected latex can be used to provide gloss higher than 60%. In a further embodiment, small-size latex can be used to provide higher gloss (about 75%). In another embodiment, matte or glossy film can be made by coating and then laminating with a pressure sensitive adhesive (“PSA”).
In an embodiment of the method of the present invention, a dual-layered film 5 including a layer of the composition of the present invention and a layer of PSA is made using a dual-layer die coating process described in U.S. Pat. No. 5,728,430 to Sartor et al. and U.S. Pat. No. 5,558,913, et al. both of which are incorporated herein by reference in their entireties.
Adhesives can be applied to one or both major surfaces of the film 5 using known processes, such as, for example, adhesive lamination. Halogen free adhesives can be used to produce halogen-free films. Examples of halogen-free adhesives include acrylic adhesives such as a hot-melt acrylic adhesive and a water-based latex acrylic adhesive. Other halogen-free adhesives include a hot-melt rubber adhesive, a silicone adhesive, thermoplastic elastomers, other halogen-free adhesives known in the art, and any combination of any of these in any proportion.
In an exemplary embodiment of the composition of present invention, the polymeric material includes vinyl acetate containing polymer with a vinyl acetate content of at least about 75%, a pigment, and a dispersant. In yet another exemplary embodiment of the composition, the polymeric material includes a vinyl acetate containing polymer with a vinyl acetate content of at least 75%, a pigment, a plasticizer, a dispersant, a wetting agent, and an ultra-violet light (“UV”) stabilizer. In other embodiments of the composition, a binder with high glass-transition temperature (“Tg”) e.g., VINAC XX-230 or VINAC 890DNP by Air Products LP of Allentown, Pa., is added in varying quantities to manipulate the mechanical properties of the film 5 formed using the composition. Generally, for a polymer, higher Tg relates to higher tensile strength and lower % elongation. The mechanical properties can also be manipulated by adding plasticizer. The film of the present invention can be abrasion resistant, easy to cut, and in some cases biodegradable.
Test Methods
The properties of the composition and film 5 of the present invention can be characterized by various analytical techniques. A brief description of these analytical techniques is given below:
Tensile Elongation
The tensile elongation of the film 5 is tested using mechanical properties measurement techniques, e.g., Instron. A modified ASTM D882 was used to determine the tensile strength and percentage elongation of the films of the present invention. The procedure is as follows:
1. A 1″×4″ specimen was cut out in the machine direction. 2. Grip the film 1″ from the end at both the ends, so the separation between the grips is 2 inches. 3. Set the crosshead speed at 12 inches per minute (“ipm”). 4. Obtain the tensile strength, which is the product of tensile stress times the thickness of the film. 5. The % elongation is reported by the machine.
The standard requires a minimum ultimate elongation of 50% and a minimum tensile strength of 0.5 pound per square inch (“psi”). The presence or absence of PSA on the film does not appreciably alter the strength and/or elongation of the film. As such, wherever the film in the examples below includes PSA, the tensile elongation test was performed using film without the layer of PSA.
Printability
The printability of the film 5 is tested by printing directly on the film specimen using solvent-based ink-jet printer. Other printing methods can include, for example, solvent screen, eco-solvent, digital, piezo ink-jet, UV screen, and UV ink-jet processes. Next, visual inspection is performed to determine if there was smudging of ink on the surface of the film and diffusion of ink inside the film. Good printing is obtained if there is no smudging and diffusion of ink.
Durability
The durability of the film 5 is tested using xenon arc weather-o-meter according to the standards of SAE J1960 (Rev. October 2004). The test method is designed to accelerate extreme environmental conditions such as sunlight, heat, and moisture (in the form of humidity, condensation, or rain) for the purpose of predicting the weatherability of the films.
EXAMPLES
The following examples describe the various embodiments of the present invention. Numerous modifications and variations within the scope of the present invention will be apparent to those skilled in the art and the present invention is not limited to the examples given below. Unless otherwise states, all parts, percentages, and ratios reported in the following examples are on a weight basis, and all reagents used in the examples were obtained, or are available, from the chemical supplier identified below, or can be synthesized by conventional techniques.
The following Table 1 provides a list of chemicals used in the following examples, identifying their supplier; function; chemical name, formula or type; percentage solids; and Tg.
TABLE 1
Materials Used in Examples
%
Material Description
Supplier
Function
Chemical
Solids
Tg ° C.
KRONOS 4311
Kronos
Pigment
TiO2
77
ZONYL FS-300
Du Pont
Surfactant
Flurosurfactant
40
TAMOL 731A
Rohm Haas
dispersant
hydrophobic
25
copolymer
AIRFLEX 465
Air Products
Binder
VAE Emulsion
67
−5
VINAC XX-230
Air Products
Binder
VA Emulsion
55
30
AIRFLEX 323
Air Products
Binder
VAE Emulsion
55
22
VINAC 890DPN
Air Products
Binder
VA copolymer
49
30
HYCAR 26349
Lubrizol
Binder
Acrylic Latex
49
12
HYCAR 26348
Lubrizol
Binder
Acrylic Latex
48.5
30
JONCRYL 617A
Johnson
Binder
Acrylic Latex
45.5
7
Polymer
SANCURE 899
Lubrizol
Binder
PU Emulsion
35
BENZOFLEX 2088
Velsicol
Plasticizer
Dipropylene
Chemical
Glycol
dibenzoate
DREWPLUS L-198
Ashland Inc.
Defoamer
Aliphatic
Petroleum
DYNASYLAN GLYEO
Degussa
coupling agent
Silane
DYNASYLAN
Degussa
coupling agent
Silane
HYDROSIL 2926
Butyl cellusolve
Dow Chemical
solvent
TINUVIN 1130
Ciba
UV absorber
hydroxyphenyl
benzotriazole
TINUVIN 292
Ciba
light stabilizer
sebacate type
CYMEL 385
Cytec Industries
Crosslinker
Melamine
Inc.
formaldehyde
EVOCAR LATEX DA-
Dow Chemical
Binder
VAE
55
12
280
TRITON X-405
Dow Chemical
Surfactant
Octylphenol
70
ethoxylate
TRITON X-45
Dow Chemical
Surfactant
Octylphenol
100
ethoxylate
XAMA 7
Lubrizol
Crosslinker
Polyaziridine
95
HYCAR 26-1265
Lubrizol
Binder
Acrylics
49
23
Ethoxylated
polyol
DISPONIL AFX4030
Cognis
Surfactant
Blend
30
RHEOLATE 350
Elementis
Thickener
Polyurethane
50
DEV 5147
Avery Dennison
Binder
VAE/acrylics
60
12-40
The chemicals used in the examples are further described below.
AIRFLEX 465: A low viscosity/high solids (67%), polyvinyl alcohol protected Vinyl Acetate-ethylene (“VAE”) emulsion with rapid set speed, available from Air Products.
AIRFLEX 323: Polyvinyl alcohol protected VAE emulsion, with standard solids (55%), high Tg, and excellent heat resistance, available from Air Products.
DISPONIL AFX 4030: Nonionic surfactant at with 40 moles ethylene oxide at 30% solids, available from Cognis Corporation of Cincinnati, Ohio.
VINAC XX-230: Polyvinyl alcohol protected VA emulsion, with standard solids at 55%, available from Air Products.
VINAC 890DPN: Polyvinyl acetate dispersion containing reactive groups, aluminum chloride hardener and small parts of a coalescence agent. Solids content is 49%, available from Air Products.
TAMOL 731A: A hydrophobic copolymer dispersant with excellent compatibility and good pigment wetting, available from Rohm Haas.
HYCAR 26349: Surfactant protected acrylic latex at 49% solids and 12° C. Tg, for durable coating/adhesives, available from The Lubrizol Corporation of Wickliffe, Ohio.
HYCAR 26348: Surfactant protected acrylic latex at 48.5% solids and 30° C. Tg, excellent oil and solvent resistance, available from The Lubrizol Corporation.
HYCAR 26-1265: Surfactant protected acrylic latex at 49% solids and 23° C. Tg, for ultra water resistance coating/adhesives, available from The Lubrizol Corporation.
RHEOLATE 350: A rheological additive from Elementis of London, United Kingdom.
DEV 5147: VAE/acrylic hybrid; Scale-up version of 1277-72.
SANCURE 899: An aliphatic polyester polyurethane dispersion at 30% solids, provides high gloss for coatings, available from The Lubrizol Corporation.
ZONYL FS-300: A general purpose nonionic fluorosurfactant that is an ideal wetting and leveling agent for aqueous application at 40% solids, available from DuPont of Wilmington, Del.
BENZOFLEX 2088: A dipropylene glycol dibenzoate plasticizer, available from Velsicol Chemical Corporation of Rosemont, Ill.
KRONOS 4311: An aqueous dispersion of titanium dioxide at 77% solids, available from Kronos of Houston, Tex.
JONCRYL 617A: Acrylic latex at 45.5% solids, 7° C. Tg, available from Johnson Polymer of Racine, Wis.
DREWPLUS L-198: An aliphatic petroleum defoamer, available from Ashland Inc. of Columbus, Ohio.
Butyl Cellusolve: An ethylene glycol butyl ether solvent, available from Dow Chemical of Midland, Mich.
CYMEL 385: A melamine formaldehyde cross linking agent, available from Cytec Industries Inc.
TINUVIN 1130: A UV absorber of the hydroxyphenyl benzotriazole class, available from Ciba of Basel, Switzerland.
TINUVIN 292: A liquid hindered amine light stabilizer for coating applications, available from Ciba.
DYNASYLAN GLYEO: A silane coupling agent (3-glycidyloxy-propyl-triethoxy silane), available from Degussa of Parsippany, N.J.
DYNASYLAN HYDROSOL 2926: A silane coupling agent (3-glycidyloxy-propyl-trialkoxy silane), available from Degussa.
EVOCAR LATEX DA-280: VAE latex, available from Dow Chemical.
TRITON X-405: Nonionic surfactant, available from Dow Chemical.
TRITON X-45: Nonionic surfactant, available from Dow Chemical.
XAMA 7: Polyaziridine, available from The Lubrizol Corporation.
1277-5A: Latex prepared according to Example 27A.
1277-5A: Latex prepared according to Example 27A.
1277-70: Latex prepared according to Example 28A.
1277-72A: Latex prepared according to Example 28A.
DEV-5147: Latex prepared according to Example 28A, available from Avery Dennison Corporation.
Example 1
In separate containers, the following mixtures were prepared:
A. 32.5 parts of KRONOS 4311 (25 parts dry) B. 2.5 part of water and 0.26 part of ZONYL FS-300 C. 2.5 parts TAMOL 731A (0.6 part dry) D. 181 parts of AIRFLEX 323 (100 parts dry) E. 0.2 part of DREWPLUS L-198
Components A, B, and C were mixed well and added to D, and then, E was added. The blend was then coated over a 1.4 mil PET film. The resulting VAE film was then peeled off from the PET film.
Example 2
In separate containers, the following mixtures were prepared:
A. 30.8 parts of AIRFLEX 465 (20 parts dry) and 145 parts of AIRFLEX 323 (80 parts dry) B. 2.5 part of water and 0.26 part of ZONYL FS-300 C. 19.5 parts of KRONOS 4311 D. 0.2 part of DREWPLUS L-198
Component B was mixed well and added to C, and then, the mixture was added to A under agitation, and next D was added. The resulting solids were 58%. The blend was then coated over a 2 mil PET film. The resulting VAE film was then peeled off from the PET film.
The above formulation of Example 2 was then prepared in a larger amount. The blend was coated on 2 mil PET at a 2.7 mil thickness. The coated film was then printed using a MIMAKI JV3 solvent ink jet printer available from Mimaki Engineering Co., Ltd. of Nagano, Japan. No color-to-color bleed was observed by visual inspection, and the quality of print was good.
Example 3
The composition of the formulation was the same as in Example 2. The formulation was scaled-up to a large volume and then coated in a pilot coater over 1.4 mil PET. The coated film was then laminated to a PSA with release liner. The coated film was about 1.9 mil. In other embodiments, the formulation is coated in the pilot coater over 0.92 mil PET or 2.0 mils PET. After peeling off the PET film, the gloss level was 82 and 96 at a 60 and 85 degree angle, respectively.
The same formulation was then coated using a dual die method over a release liner with VAE emulsion on the top and PSA emulsion (AROSET 3300 from Ashland Inc.) in between the VAE emulsion and the release liner. In addition to coating using a dual die method, in other embodiments, the formulation is coated using slide coating, reverse scroll, slot die, and/or curtain coating methods. In wet state, it formed a good two-layer type of coating.
Example 4
The composition of the formulation was the same as in A of Example 2, except the binder system was 30 parts dry AIRFLEX 465 and 70 parts dry AIRFLEX 323.
Example 5
The composition of the formulation was the same as in A of Example 2, except the binder system was 43 parts dry VINAC 230 and 57 parts dry AIRFLEX 323 at 20 parts BENZOFLEX 2088.
Example 6
The composition of the formulation was the same as Example 5 except VINAC 890DPN was used instead of VINAC XX-230. Also, 21 parts of BENZOFLEX 2088 were used instead of 20 parts.
Example 7
The same as Example 6 except no BENZOFLEX 2088 was used in the formulation.
Example 8
The same as Example 6 except 5 parts of BENZOFLEX 2088 were used.
Example 9
The same as Example 6 except 10 parts of BENZOFLEX 2088 were used.
Example 10
The same as Example 5 except 10 parts of BENZOFLEX 2088 were used.
Example 11
The same as Example 2 except 0.4 part of TAMOL 731A was included in the formulation. Also, 18 parts of KRONOS 4311 were used instead of 15 parts.
Example 12
The same as Example 11 except 25 parts of KRONOS 4311 were used instead of 18 parts.
Example 13
The same as Example 5 except 70 parts of AIRFLEX 323 and 30 parts of VINAC XX-230 were used instead of 57 parts of AIRFLEX 323 and 43 parts of VINAC XX-230. Also, the amount of BENZOFLEX 2088 was 5 parts instead of 20 parts.
Example 14
The same as Example 1 except 90 parts of AIRFLEX 323 and 10 parts of VINAC XX-230 were used instead of 100 parts AIRFLEX 323, respectively. Also, 0.4 part of TAMOL 731A was used instead of 0.6 part.
Example 15
The same as Example 14, except 80 parts of AIRFLEX 323 and 20 parts of VINAC XX-230 were used instead of 90 parts of AIRFLEX 323 and 10 parts of VINAC XX-230, respectively.
Example 16
The same as Example 14 except 10 parts of VINAC XX-230 were replaced by 10 parts VINAC 890DPN.
Example 17
The same as Example 15 except 20 parts of VINAC XX-230 were replaced by 20 parts of VINAC 890DPN.
Example 18
The same as Example 15 except 20 parts of VINAC XX-230 were replaced by 20 parts of HYCAR 26349.
Example 19
The same as Example 15 except 20 parts of VINAC XX-230 were replaced by 20 parts of HYCAR 26348.
Example 20
The same as Example 15 except 20 parts of VINAC XX-230 were replaced by 20 parts of JONCRYL 617A.
Example 21
The same as Example 15 except 20 parts of VINAC XX-230 were replaced by 20 parts of SANCURE 899.
Example 22
The same as Example 1 except 2 parts of DYNASYLAN GLYEO also were included in the formulation.
Example 23
The same as Example 1 except 2 parts of DYNASYLAN HYDROSIL 2926 also were included in the formulation.
Example 24
The composition of the formulation was the same as Example 4 except 2 parts of TINUVIN 1130 and 1 part of TINUVIN 292 were dissolved in 5 parts of ethylene glycol n-butyl ether (Aldrich) and added to the blend. The coated film 5 was tested using a xenon weather-o-meter for durability.
The compositions of the various formulations used in the above examples are summarized in Table 2 below. Table 3 summarizes film thickness, opacity, and mechanical properties of the coated films.
Example 25
The same as Example 15 except 80 parts of AIRFLEX 323 and 20 parts of VINAC XX-230 were replaced by 50 parts of HYCAR 26349 and 50 parts of HYCAR 26348, respectively.
Example 26
The same as Example 15, except 3 parts of CYMEL 385 were included in the formulation.
Example 27A
VAE-Acrylic Hybrid Emulsion Preparation
Following solutions are prepared:
A1: 273 gm of EVOCAR LATEX DA-280 A2: 1 gm water and 1 gm of TRITON X-405 A3: 2 gm of butyl acrylate and 6 gm of methyl methacrylate B1: 30 gm of water, 12 gm TRITON X-405, and 0.9 gm TRITON X-45 B2: 50 gm of butyl acrylate, 100 gm methyl methacrylate, and 7.5 gm acrylic acid C: 18 gm water and 0.6 gm of t-butyl hydrogen peroxide D: 18 gm water, 0.6 gm sodium formaldehyde sulfoxylate, 0.1 gm TRITON X-405.
Process:
1. A1 and A2 were charged to the 1-Liter reactor and purge with nitrogen for at least 30 minutes. 2. Start agitation and add A3. 3. Make a pre-emulsion of B by adding B2 to B1 under high-shear mixing. 4. Start heating up, and at 50° C., start adding slowly C and D over 3 hours. 5. 10 minutes later, start adding slowly B over 2 hours at 55° C. 6. After the slow-adds, continue slow-adding C and D for another 30 minutes. Then cool and discharge.
The resulting latex (1277-5A) has 4.5 pH, 70 centipoise (“cps”) in viscosity at 62.3% solids.
Example 27B
The formulation is the same as Example 15, except that latex 1277-5A is prepared according to Example 27A was adjusted to pH 7 by adding 7% ammonium hydroxide solution and was then used instead of AIRFLEX 323 and VINAC XX-230. Also, TAMOL 731A was not used.
Example 27C
The same as 27B except 2% XAMA 7 (polyaziridine) was included.
Example 28A
Following latexes were made with the process as Example 27. The main composition is listed below.
Code
1277-70
1277-72
DEV 5147
Scale
1L
1L
Drum
Composition
EVOCA DA280*
100
100
100
BA
56
30
30
MMA
111
70
70
AA
8.3
5
5
Physical Properties
% Solids
63.6
62
60.8
pH
6.9
7.0
7.5
Viscosity (cps)
220
42
1020
*Dry
Example 28B
In separate containers, the following mixtures were prepared:
F. 157.2 parts of 1277-70 (100 parts dry) G. 1.5 parts of water and 1.5 parts of TRITON X-405 H. 2 part of water and 0.23 part of ZONYL FS-300 I. 1.6 parts TAMOL 731A (0.4 part dry) J. 32.5 parts of KRONOS 4311 (25 parts dry) K. 0.2 part of DREWPLUS L-198 L. 1 part of water and 1 part of XAMA 7
The components were added to a glass container under mixing. The blend was then coated over a 1.42 mil PET film at 2-mil thick.
Example 28C
The same as 28B except 2 parts of water and 2 parts of XAMA 7 were used in G.
Example 28D
The same as 28B except 163.4 gm of 1277-72 latex were used in A.
Example 28E
The same as 28D except 2 parts of water and 2 parts of XAMA-7 were used in G.
Printing quality of the above 4 coated films 5 (Examples 28B, C, D, E) were quite similar to the cast vinyl by a digital ink jet printer.
Example 29A
The same as Example 28B, Except 164 gm of DEV 5147 were used in A, 2.3 gm of DISPONIL AFX 4030 were used in B, and no XAMA-7 was used in G. The resulting formulation was coated over 1.42 mil PET at 1.8 mil (refer as print layer). On the top of this coated film, it was further coated with the following emulsion blends strengthening layer: 52 parts of VINAC DPN 890, 45 parts of DUR-O-SET E130, 1 part of water, and 0.3 part of ZONYL FS300 at different thickness. The coated film was dried in the 85° C. oven for 5 minutes.
Example 29B
The same as Example 29A except HYCAR 26-1265 was used instead of DEV 5147 in A and 1 part of water and 1 part of XAMA-7 were used in G. For coating purpose, 1.3 parts of RHEOLATE 350 were added to increase the coating viscosity. The resulting coating has 1.5 mils in thickness. On the top of this film, it was also coated at different thickness. The following table shows the performance.
Thickness
Mechanical Properties
(mil)
Tensile (lb/in)
%
Young's
Print
at
Elongation
Modulus
Opacity
Digital
Example
layer
S.L.*
yield
at break
at break
(Mpa)
(%)
Weeding
Printing
29A
1.8
0.0
2.7
2.6
127
389
91.95
poor
1.8
0.5
4.6
4.8
199
494
90.61
poor
1.8
1.5
4.6
4.8
199
494
90.61
marginal
good
1.8
1.8
7.7
8.8
256
670
90.90
good
29B
1.5
0.0
0.9
3.0
282
273
90.65
poor
1.5
0.7
2.6
5.4
340
357
91.09
marginal
1.5
1.0
3.5
5.2
260
417
91.45
v.good
good
1.5
1.4
4.4
7.8
365
466
91.42
good
*strengthening layer
The results suggest that both VAE/acrylic hybrid and acrylic base films 5 can be made at high tensile with strengthening layer. The laminate was made by laminating with PSA transfer tape with liner to the strengthening layer, and removal of the PET. The resulting laminate can be printed and weeded well.
Example 30
Examples of 30A and 30B are same composition as 29A and 29B with different thickness of the strengthening layer respectively. The results are in the Table below.
Gloss
Thickness (mil)
Tensile (lb/in)
% Elongation
60
Sample ID
print
S.L.
total
at yield
at break
at break
Opacity
Degree
30A
2.0
1.7
3.7
7.1
8.5
180
91.1
84.0
30B
2.0
1.3
3.3
5.2
8.2
230
91.5
91.4
TABLE 2
Composition of formulations used in Examples
AIRFLEX
HYCAR
VAE/
AIRFLEX
VINAC
VINAC
HYCAR
HYCAR
JONCRYL
Example
323
26-1265
acrylic
465
230
890DPN
26348
26349
617A
1
100
2
80
20
3
80
20
4
70
30
5
57
43
6
57
43
7
57
43
8
57
43
9
57
43
10
57
43
11
80
20
12
80
20
13
70
30
14
90
10
15
80
20
16
90
10
17
80
20
18
80
19
80
20
20
80
20
21
80
22
100
23
100
24
70
30
25
50
50
26
80
20
27B
100
27C
100
28B
100
28C
100
28D
100
28E
100
29A
100
29B
100
30A
100
30B
100
XAMA
CYMEL
KRONOS
TAMOL
BENZOFLEX
TINUVIN
Tinuvin
Example
7
385
4311
731A
2088
1130
292
1
20
0.6
2
15
3
15
4
15
5
15
20
6
15
21
7
15
8
15
5
9
15
10
10
15
10
11
18
0.4
12
25
0.4
13
15
5
14
25
0.4
15
25
0.4
16
25
0.4
17
25
0.4
18
25
0.4
19
25
0.4
20
25
0.4
21
25
0.4
22
25
0.6
23
25
0.6
24
15
2
1
25
25
0.4
26
3
25
0.4
27B
27C
2
28B
1
25
0.4
28C
2
25
0.4
28D
1
25
0.4
28E
2
25
0.4
29A
1
25
0.4
29B
1
25
0.4
30A
1
25
0.4
30B
1
25
0.4
Note:
1. Compositions are normalized based on 100 dry binder.
2. All formulations contain about 0.26% ZONYL FS-300 and 0.2% DREWPLUS L-198 based on 100 parts dry binder
TABLE 3
Properties of films made in Examples
Coated
Tensile
% Elongation
Thickness
%
(lb/in)
at
at
Example
(mil)
Opacity
at Yield
Yield
Break
1
2.5
94
1.7
22
260
2
2.8
92
1.7
25
310
3
1.9
85
0.9
25
380
4
2
87
0.7
26
280
5
2.75
91
0.5
35
300
6
2.7
90
0.4
48
366
7
3
93
5.3
10
237
8
2.8
91
2.9
10
357
9
3
93
2.1
5
390
10
3
93
1.3
70
375
11
2.4
91
1
30
250
12
2.3
94
1
30
291
13
2.6
87
2.1
15
312
14
2.3
92
1.8
19
279
15
2.4
91
2.2
15
237
16
2.2
92
1.5
20
348
17
2.2
93
2.1
19
191
18
2.1
94
1.3
22
273
19
2.4
94
2.1
8
140
20
2.3
94
1.2
5
250
21
2
90
0.6
40
249
22
2.3
93
0.7
25
395
23
2.3
93
1.4
25
313
24
2.5
94
0.4
50
365
25
2.1
94
4
5
65
26
2.3
93
3
11
210
27B
2.3
96
2.8
8
200
27C
2.5
97
3.6
8
150
All of the features disclosed in the specification, including the claims, abstract, and drawings, and all of the steps in any method or process disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed in the specification, including the claims, abstract, and drawings, can be replaced by alternative features serving the same, equivalent, or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
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A composition that is configured for use in creating a film. The composition includes a vinyl acetate containing polymer, such as a vinyl acetate ethylene (VAE) copolymer, and at least one additive that is a pigment, a surfactant, a dispersant, a wetting agent, a plasticizer, a defoamer, a coupling agent, a solvent, a UV absorber, a fire retardant, or a light stabilizer.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] A relevant subject matter is disclosed in a co-pending U.S. patent application (Attorney Docket No. US30358) filed on the same date and entitled “HINGE,” which is assigned to the same assignee as this patent application.
BACKGROUND
[0002] 1. Technical Field
[0003] The present disclosure relates to a hinge.
[0004] 2. Description of Related Art
[0005] A foldable device, such as a notebook computer, or a foldable mobile phone, generally includes a base and a cover pivotably mounted to the base via a hinge. The hinge generally includes a pivot shaft, a first leaf, and a second leaf. The first leaf is mounted to the base, and the second leaf is mounted to the cover. A twisting force is required to overcome a friction between the second leaf and the pivot shaft to rotate the cover relative to the base. However, the friction between the second leaf and the pivot shaft remains the same when the device is unfolded. The twisting force required also remains the same, which gives a user an uneasy feeling.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is an exploded, isometric view of a first exemplary embodiment of a hinge.
[0007] FIG. 2 is similar to FIG. 1 , but viewed from another perspective
[0008] FIG. 3 is an assembled, isometric view of the hinge of FIG. 2 .
[0009] FIG. 4 is similar to FIG. 3 , but showing a different state.
[0010] FIG. 5 is an exploded, isometric view of a second exemplary embodiment of a hinge.
[0011] FIG. 6 is similar to FIG. 4 , but viewed from another perspective.
[0012] FIG. 7 is an assembled, isometric view of the hinge of FIG. 6 .
[0013] FIG. 8 is similar to FIG. 7 , but showing a different state.
DETAILED DESCRIPTION
[0014] Referring to FIGS. 1 and 2 , a first exemplary embodiment of a hinge includes a pivot shaft 10 , a first leaf 20 , a second leaf 30 , a first knuckle 40 , a resilient assembly 50 , two washers 60 , and a fastener 70 .
[0015] The pivot shaft 10 includes a fixing rod 12 having a substantially non-circular cross-section. A first end of the fixing rod 12 forms a threaded portion 120 , and a second end of the fixing rod 12 opposite to the first end forms a non-circular combination block 16 . A cylindrical flange 14 extends between the non-circular combination block 16 and the fixing rod 12 .
[0016] The first leaf 20 is fixed to a base of a foldable device (not shown), such as a notebook computer, and includes a combination portion 22 . The combination portion 22 defines a non-circular fixing hole 24 corresponding to the non-circular combination block 16 .
[0017] The second leaf 30 is fixed to a cover of the foldable device, and includes a second knuckle 32 . The second knuckle 32 includes a first end surface 34 facing the first knuckle 40 , and a second end surface 36 opposite to the first end surface 34 . A round through hole 38 is defined in a center of the second knuckle 32 . The fixing rod 12 of the pivot shaft 10 extends through the round through hole 38 . A tab 340 extends from a side of the first end surface 34 . The tab 340 may be arc-shaped. Two engaging surfaces 342 are formed on opposite ends of the tab 340 .
[0018] The first knuckle 40 fits about the cylindrical flange 14 . The first knuckle 40 defines an incision 42 parallel with an axial direction of the first knuckle 40 . An engaging portion 44 is formed on a first end of the first knuckle 40 , extending from the incision 42 , facing the second knuckle 32 . The engaging portion 44 is corresponding to the tab 340 . Two engaging surfaces 442 are formed on opposite ends of the engaging portion 44 .
[0019] The resilient assembly 50 includes a plurality of elastic elements stacked together. Each elastic elements defines a round through hole 52 through which the fixing rod 12 extends.
[0020] Each washer 60 includes a first end surface 62 facing the second knuckle 32 of the second leaf 30 , and a second end surface 64 opposite to the first end surface 62 . A non-circular through hole 66 is defined in a center of the washer 60 . The through hole 66 is through the first end surface 62 and the second surface 64 . The fixing rod 12 extends through the through hole 66 .
[0021] In one embodiment, the fastener 70 is a screw cap.
[0022] Referring to FIG. 3 , during assembly, the combination block 16 is received and fixed in the fixing hole 24 . The first knuckle 40 , the second leaf 30 , one washer 60 , the plurality of elastic elements of the resilient assembly 50 , and the other washer 60 are sleeved on the pivot shaft 10 in that order. The first knuckle 40 fits about the cylindrical flange 14 . The first end surface 34 engages an end of the cylindrical flange 14 . The fastener 70 engages with the threaded portion 120 , thus fixing the fastener 70 to the pivot shaft 10 , to prevent the washers 60 , the resilient assembly 50 , the second leaf 30 , and the first knuckle 40 from disengaging from the pivot shaft 10 .
[0023] Referring to FIG. 4 , to open the foldable device from a folded/closed state, initially, a twisting force f 1 is required to overcome a friction between the second end surface 36 and the first end surface 62 of the washer 60 , a friction between the second leaf 30 and the fixing rod 12 , and a friction between the first end surface 34 and the cylindrical flange 14 , to rotate the second leaf 30 relative to the pivot shaft 10 . When one of the engaging surfaces 342 of the second leaf 30 engages one of the engaging surfaces 442 of the first knuckle 40 , a twisting force f 2 is required to simultaneously rotate the second leaf 30 and the first knuckle 40 relative to the pivot shaft 10 . Obviously, the twisting force f 2 further overcomes a friction between the first knuckle 40 and the cylindrical flange 14 . Therefore, the twisting force f 2 is larger than the twisting force f 1 .
[0024] To close the foldable device from a unfolded/opened state, initially, the twisting force f 1 is required to rotate the second leaf 30 relative to the pivot shaft 10 . When the other engaging surface 342 of the second leaf 30 engages the other engaging surface 442 of the first knuckle 40 , the twisting force f 2 is required to simultaneously rotate the second leaf 30 and the first knuckle 40 relative to the pivot shaft 10 .
[0025] Referring to the FIGS. 5 and 6 , a second exemplary embodiment of a hinge includes a first leaf 80 and a first knuckle 90 . Other structures of the second exemplary embodiment of the hinge are similar to the first exemplary embodiment of the hinge.
[0026] The first leaf 80 is fixed to the base of the foldable device, and includes a combination portion 82 . The combination portion 82 defines a non-circular hole fixing hole 84 , corresponding to the non-circular combination block 16 . A positioning portion 86 extends from a side of the combination portion 82 , facing to the first knuckle 90 . The positioning portion 86 is arc-shaped. Two positioning surfaces 862 are formed on opposite ends of the positioning portion 86 .
[0027] The first knuckle 90 fits about the cylindrical flange 14 . The first knuckle 90 defines an incision 92 parallel with an axial direction of the first knuckle 90 . An engaging portion 94 and an blocking portion 96 are staggeredly formed on two opposite ends of the first knuckle 90 , reversely extending from the incision 92 . The engaging portion 94 is corresponding to the tab 340 . The blocking portion 96 is corresponding to the positioning portion 86 . The engaging portion 94 faces the second knuckle 32 . The blocking portion 96 faces the combination portion 82 . Two engaging surfaces 942 are formed on opposite ends of the engaging portion 94 . Two blocking surfaces 962 are formed on opposite ends of the blocking portion 96 .
[0028] Referring to FIG. 7 , during assembly, the combination block 16 is received and fixed in the fixing hole 84 . The first knuckle 90 , the second leaf 30 , one washer 60 , the plurality of elastic elements of the resilient assembly 50 , and the other washer 60 is sleeved on the pivot shaft 10 in that order. The first knuckle 90 fits about the cylindrical flange 14 . The first end surface 34 of the second leaf 30 engages an end of the cylindrical flange 14 . The fastener 70 engages with the threaded portion 120 of the pivot shaft 10 , thus fixing the fastener 70 to the pivot shaft 10 , to prevent the washers 60 , the resilient assembly 50 , the second leaf 30 , and the first knuckle 90 from disengaging from the pivot shaft 10 .
[0029] Referring to FIG. 8 , to open the foldable device from a folded/closed state, initially, a twisting force f 3 is required to overcome a friction between the second end surface 36 and the first end surface 62 of the washer 60 , a friction between the second leaf 30 and the fixing rod 12 , and a friction between the first end surface 34 and the cylindrical flange 14 , to rotate the second leaf 30 relative to the pivot shaft 10 . When one of the engaging surfaces 342 of the bracket 30 engages one of the engaging surfaces 942 of the first knuckle 90 , a twisting force f 4 is required to simultaneously rotate the second leaf 30 and the first knuckle 90 relative to the pivot shaft 10 . Obviously, the twisting force f 4 further overcomes a friction between the first knuckle 90 and the cylindrical flange 14 . The twisting force f 4 is larger than the twisting force f 3 . When one of the blocking surfaces 962 engages with one of the positioning surfaces 862 of the first leaf 80 , the first leaf 80 prevents the second leaf 30 and the first knuckle 90 from simultaneously rotating relative to the pivot shaft 10 .
[0030] To close the foldable device from a unfolded/opened, initially, the twisting force f 3 is required to rotate the second leaf 30 relative to the pivot shaft 10 . When the other engaging surface 342 of the bracket 30 engages the other engaging surface 942 of the first knuckle 90 , the twisting force f 4 is required to simultaneously rotate the second leaf 30 and the first knuckle 90 relative to the pivot shaft 10 .
[0031] It is to be understood, however, that even though numerous characteristics and advantages of the present disclosure have been set forth in the foregoing description, together with details of the structure and function of the disclosure, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
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A hinge includes a first leaf, a pivot shaft mounted to the first leaf, a first knuckle rotatably mounted to the shaft, a second leaf rotatably mounted to the shaft, a resilient assembly mounted to the shaft, and a fastener fixed to the shaft. One end of the first knuckle forms an engaging portion, and the second leaf correspondingly forms a tab to engage with the engaging portion. Upon the condition that the tab engages with the engaging portion such that the first knuckle can rotate with the second leaf, a larger twisting force is needed for the second leaf, together with the first knuckle, to rotate relative to the pivot shaft due to further overcome a friction between the first knuckle and the pivot shaft.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention provides a system and apparatus for a low cost, long range, power efficient wireless system that provides identification and locational information.
2. Description of Related Art
The wireless Local Area Networks (LAN), based on the 802.11(a/b/g/n) standard, support short range communications between portable devices such as notebooks. The system design employs Time Division Duplex (TDD) and Orthogonal Frequency Division Multiplexing (OFDM) modulation that is optimized for high data throughput in an indoor fading environment. In order to fairly share the wireless medium among different devices, the network protocol tries to keep a single node from occupying the medium for a long period of time by limiting the lowest allowable signaling rate. Since the required signal-to-noise ratio for a given bandwidth is proportional to the signaling rate, the achievable communication range for a wireless LAN is limited.
Wide Area wireless Networks (WAN), such as cell phone networks, on the other hand, are optimized for a larger number of users and longer range. The system design employs either Frequency Division Duplexing (FDD) or Time Division Duplexing (TDD) and wideband Code Division Multiple Access (CDMA) or OFDM modulation to support a variety of services including high peak data traffic, continuous low rate voice traffic, continuous broadcast multimedia traffic, and short data bursts for paging messages. A cell phone base station with 40 watts of transmission power and an antenna at the top of a tower can provide a coverage area in excess of 2 miles in diameter. This long range communication is achieved primarily by the placement of the base station antenna at the top of the tower to overcome the signal loss due to building blockage. A typical cell phone battery can last for a few hours of continuous use and a week of stand-by time. The cell phone network also provides security against illegal access to the network and eavesdropping, but does not protect against unauthorized radiators within the band and/or jammers.
ZigBee is a specification based on the IEEE 802.15.4 standard for low cost, low power, wireless mesh networking. The targeted application is wireless control and monitoring. The low power usage of ZigBee devices allows a longer battery life and smaller batteries. The mesh networking attribute provides higher reliability and longer range. Because ZigBee can be activated (going from sleep to active mode) in 15 msec or less, the latency can be very low, and devices can be very responsive, particularly compared to Bluetooth, which has delays in waking up that are typically around three seconds. Since ZigBee is in sleep mode most of the time, its average power consumption can be very low, resulting in a longer battery life.
In beacon-enabled networks, special network nodes called ZigBee routers transmit periodic beacons to confirm their presence to other network nodes. Nodes sleep between beacons, thus lowering their duty cycle and extending their battery life. Beacon intervals range from 15.36 milliseconds to 3.287 seconds at 250 kbit/s, from 24 milliseconds to 5.136 seconds at 40 kbit/s and from 48 milliseconds to 10.272 seconds at 20 kbit/s. However, a low duty cycle operation with long beacon intervals requires precise timing, which is in direct conflict with the need for a low product cost. Alternatively, in non-beacon-enabled networks, an unslotted Carrier Sense Medium Access/Collision Avoidance (CSMA/CA) channel access mechanism can be used. In this type of network, ZigBee routers typically have their receiver continuously in the active mode, which requires a more robust power supply. However, this allows for a heterogeneous network in which some devices receive continuously, while others only transmit when an external stimulus is detected. Thus, longer battery life is achievable by one of two means: a continuous network connection and a slow but steady battery drain, or an intermittent connection and an even slower battery drain. To keep the power consumption requirements low in ZigBee devices, the expected range is from 10 to 70 meters.
For wireless systems that provide identification and location information, there is a need for security, long range, high mobility, and near full connectivity with acceptable latency using low cost, low power, compact and light weight devices.
SUMMARY OF THE INVENTION
The present invention provides a method and system for establishing a highly mobile, long range secure wireless network with dynamic topologies and near full connectivity with acceptable latency using low cost, low power, compact and lightweight devices. One aspect of the system provides a highly mobile network with dynamic network topologies and a time varying wireless medium that has neither absolute nor readily observable boundaries outside of which radio nodes are known to be unable to receive network frames. The desirable open field boundary of the system is about 1 mile in radius from the base station node. While boosting the transmit power can increase the transmission distance, it is also desirable to meet FCC requirements and maintain a low power, light weight, compact form factor which is portable or can be embedded into other devices, avoids an excessive heat dissipation requirement on the mobile node, and avoids the use of large battery. While a lower data rate can assist in providing increased range, it also increases the duration a medium is occupied. As a result, when the number of mobile nodes in the network increases, the system latency can increase to an unacceptable level. While most of the conventional networks emphasize increased capacity and data throughput, the present invention provides a range increase with acceptable battery size and system latency.
The present invention uses a low complexity, constant envelope modulation with a low data rate which is insensitive to the nonlinearity allowed for high efficiency amplifiers both in the transmitter and the receiver. The system employs a synchronized time slot frequency hopping technique, in which the base station node periodically transmits beacons and the mobile nodes are time synchronized to the base station node and hop with the same pseudo-random pattern. In order to reduce the system latency and power consumption, short packets, optimized to carry essential information but expandable to support other system functions, are employed for transmitting and receiving the system data. To deal with multipath and fading, the present invention employs both antenna diversity and the frequency (time) diversity. The frequency diversity is a result of the frequency hopping technique. This combination ensures that the longest range can be achieved with lowest power consumption.
In order to simplify the system processing complexity, the present invention employs a slotted time frame structure with two types of time slots. A “contention-access time” slot allows uncoordinated access to the network by the mobile nodes and an “allocated time” slot provides dedicated time slots to certain nodes which can communicate in a coordinated and an interference free fashion within the network. Such a frame structure maintains the simplicity of low power operation and low complexity random access by mobile nodes while, at the same time, supporting a number of advanced features such as capacity expansion, reduced latency, and range extension.
In the present invention, the mobile nodes acquire and synchronize to the base station beacons. To provide security to the system, the mobile nodes and the base station share a secret key. The mobile nodes retrieve the “state” of the hopping sequence from the beacons and, together with the secret key, locally generate a matched and synchronized hopping pattern. The mobile nodes enter into a power save state unless it is time for them to listen for the base station beacon or it is time for the mobile nodes to transmit. The mobile node does not need to listen to every base station beacon. The duration of the power save state can be controlled by assigning flags to the mobile nodes. By minimizing the duration of the wake state and the number of transmissions, a mobile node can conserve battery power. The present invention also provides for calibrating the clock of the mobile nodes for a longer power save state.
As the number of mobile nodes within the network increases, the present invention provides a technique of system capacity expansion by engaging additional base station nodes to deal with the increased traffic and increased system latency. An additional slave base station, with its clock synchronized to the master base station node, hops at a different frequency hopping pattern and can be used to divert some mobile node traffic from the master base station node in order to maintain the latency of the system and avoid excessive packet collisions. The system capacity expansion is a form of FDMA (frequency-division multiple access) since the additional slave base station uses a different frequency channel. To maintain time synchronization with the master base station node, the slave base stations listen to the master base station beacon. Additionally, the slave base stations are assigned a beacon transmission time which is offset from the master base station and other slave base stations. The master base station node and the slave base station nodes typically communicate at a higher data rate with each using designated (allocated) time slots to exchange information. Some mobile nodes with enhanced capability can be converted to act as slave base station nodes as needed. When the master base station is incapacitated or destroyed, the slave station can continue to operate on its own for a while until one of the slave stations can become the master station. This allows the system to survive without significant interruption and degradation in performance in the adverse situation.
The system of the present invention also controls the reporting period of mobile nodes by assigning them different flags. The flag is set as part of the mobile node profile but can also be overwritten by the base station. Depending on the requirements, mobile nodes that do not need to report to the base station frequently are assigned flags which have longer reporting periods. In this way, the base station can also control the amount of system traffic.
Another aspect of the present invention is to be robust against other signals which can be sharing the wireless medium or hostile interferers intentionally jamming the medium. The system employs the conventional CSMA/CA with random back-off to regulate the network traffic. When this technique is overlaid on the frequency hopping, the system has added robustness against other signals which can be sharing the wireless medium or hostile interferers intentionally jamming the medium. The system can deal with large or small numbers of mobile nodes by controlling the access back-off timer. When a large number of mobile nodes are in the system, the back-off time can be increased to reduce the number of packet collisions. This allows the system to maintain a constant throughput for the network.
Another aspect of the system of the present invention deals with the lack of full connectivity such that some nodes cannot hear other nodes within the same network. The system can extend its coverage by engaging slave base stations at the edge of coverage to capture more mobile nodes which are beyond the raw coverage of the master base station. A slave base station node can relay the information from hidden mobile nodes back to the master base station using designated time slots. A large number of base stations are allowed to simultaneously operate within an area without adversely interfering with each other to achieve full or near full connectivity of the mobile nodes and large system capacity with acceptable latency.
A feature of the present invention is that it uses the time, frequency, and space (geographic) domains to optimize its capacity. It also can adjust the “update” rate (latency) of the system to accommodate more nodes and higher traffic.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of frequency/time slots within a session.
FIG. 2 is a schematic diagram of antenna selection diversity.
FIG. 3 is a schematic diagram of a flow chart of a Q-factor adjustment algorithm.
FIG. 4 is a schematic diagram of a wireless network for identification and location of mobile nodes.
FIG. 5 is a schematic diagram of the extension of the coverage area by the use of a slave base station.
FIG. 6 is a schematic diagram of the use of rate adaptation.
FIG. 7 is a schematic diagram of one embodiment of a packet structure.
DETAILED DESCRIPTION
The present invention provides a low power, long range, secure, and fully mobile (base station and handset) radio network. The present invention achieves a long range while maintaining low power consumption. Other aspects of the invention deal with low network latency while accommodating a large number of mobile nodes and achieving full connectivity of the system. The present invention provides a method and system for establishing a highly mobile, long range, secure, wireless network with dynamic topologies, near full connectivity and acceptable latency using low cost, low power, compact and lightweight devices.
A UHF slow frequency hopping system with Minimum Shift Keying (MSK), Gaussian Minimum Shift Keying (GMSK), Frequency Shift Keying (FSK) or Staggered Quadrature Phase Shift Keying (SQPSK) types of constant envelope modulation schemes that can be demodulated with a simple receiver is used in the present invention. It is suitable for an implementation with a low cost microprocessor, such that a reasonable acquisition time (within a couple seconds) can be achieved. To achieve the goal, the base station starts a network by transmitting a beacon at selected intervals based on a selected frequency hopping pattern. The selected frequency hopping pattern uses a sequence generator with a secure seed that is shared among the base station and the mobile nodes. The base station beacon carries the state of the sequence generator in its beacon. The state, together with the seed, allows the mobile nodes to generate the same synchronized hopping sequence. A mobile node performs its initial hopping sequence acquisition by setting its receiver to a continuous receiving mode. It either stays in a frequency bin to wait for the base station signal or hops with a different pattern or period. After a short duration, the base station beacon will fall into the same frequency bin as the mobile node receiver. The mobile receiver then demodulates the signal, establishes the timing synchronization, and retrieves the state of the hopping sequence to establish the same hopping pattern thereafter.
In order to simplify the processing complexity, the present invention employs a simple slotted time frame structure with a duration established by two consecutive beacons. The beacon interval is broadcast as part of the beacon data and is generally static but can be adjusted for flexibility. Frequency hopping can be determined by changing a transmit frequency every dwell time slot of a frame and having an adjustable number of dwell time slots per frame. As illustrated in the FIG. 1 , the beacon is the timing master which establishes the frame with an integer number of time slots. Beacon frame 10 contains two types of time slots, namely, contention-access time slots 11 and allocated time slots 12 . Contention-access time slots 11 are used for transmission by mobile nodes using the Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) protocol. This allows mobile nodes to independently access the network without coordination with other mobile nodes. During contention based time slots 11 , beacon 13 from the base station, and packets 14 - 22 are transmitted. Each packet 14 - 22 comprises Gap Time 23 , packet 24 from a mobile node, and ACK/NAK 25 from the base station. The base station can also assign dedicated time slots for communication by specific nodes in allocated time slots 12 which are free from interference from other nodes. Allocated time slots 12 are specified in the beacon data by the base station with a certain offset from beacon packet 13 with the duration in units of time slots. Allocated time slots 12 can comprise packet 26 from another base station, and packets from mobile nodes plus ACK/NAKs 27 - 30 .
Once initial acquisition is achieved, a mobile node can synchronize its timing according to the beacon and it initiates its power saving mode while maintaining network connectivity if the network does not require any active update of the mobile node information. The frequency hopping feature also allows the system to be robust against unintentional interferers or intentional jammers. This feature also allows multiple base stations to simultaneously access the network.
A constant envelope type of signal allows a transmitter to use a Class C type (or other highly efficient type) of amplifier to reduce peak and average power consumption and also allows a receiver to use high efficiency and high gain logarithmic amplifiers and low complexity signal processing to reduce power consumption. A simple demodulator reduces the receiver complexity. The operation of a high efficiency power amplifier in combination with the realization of a low power receiver achieves the highest efficiency in terms of DC power consumption for the amount of data transfer. Such features permit the use of a reasonable size battery, extend operational life (without battery recharge or replacement) and remove the requirement of a bulky heat sink.
For wireless signal propagation, well-defined coverage areas simply do not exist. Propagation characteristics are dynamic and unpredictable. Small changes in position or direction may result in dramatic differences in signal strength. Similar effects occur whether a network node is stationary or mobile (as moving objects may impact station-to-station propagation). This type of phenomenon is called multipath fading, and the rate of fading is related to how fast the node moves and the medium changes. The present invention provides a combination of antenna diversity and frequency/time diversity techniques which retain a compact, low cost, and low power design. In one embodiment, antenna diversity is provided by using patch antenna elements with switched selection capability, which is illustrated in FIG. 2 . Switched diversity system 31 comprises antenna elements 32 - 35 and diversity switch 36 which selects which one of antenna elements 32 - 35 to connect to output 37 . The use of frequency hopping provides frequency and time diversity through the re-transmission of signal packets at different frequency bins and time slots.
To deal with a large number of network nodes, the system employs short packets for signaling such that each node does not occupy significant time. Once initial acquisition is achieved, the mobile nodes enter into a power saving state unless it is time to listen for the base station beacon or it is time for a mobile node to transmit. The mobile node does not need to listen to every base station beacon. The duration of the power saving state can be controlled by assigning flags to the mobile nodes. The flag is generally set in the mobile node based on its user profile but can be overwritten by the base station based on network usage. This initial flag assignment is established when the mobile node first associates with the base station based on the profile of the mobile station in the association request. By minimizing the duration of the wake state and the number of transmissions, a mobile node can conserve battery power. If the base station requires more or less frequent updates of the mobile node information, it can send a command to change the flag of the mobile node. This has the effect of lengthening or shortening the power save state duration. A most frequent update can be to require the mobile node to listen for a beacon every frame and respond as soon as possible to a query from the base station.
The power consumption of a mobile node is predominately determined by the duration it needs to listen to the beacon and transmit a packet. In the power saving state, a mobile node can shut off unnecessary operations while maintaining a sleep timer running at a low clock rate. The sleep timer is pre-set to wake up the mobile node after a number of clock cycles in order to receive a beacon. The longer the sleep time is, the larger the clock offset and the drift-induced timing offset. The mobile node can wake up ahead of the beacon to accommodate the clock drift induced offset. The precise clock drift can be calibrated with the actual beacon time established at the reception of frame sync in the beacon. By calibrating the clock offset and drift with the beacon timing over a short duration, the induced timing offset can be reduced and the wake up instant can be improved. The resolution of the calibration can be improved using multiple sleep clocks, a slow clock for the bulk of the sleep duration and a faster clock as the wake up time approaches to provide better resolution for timing calibration. If the relative position and velocity of the mobile node and the base station are known, the motion-induced Doppler can be removed in the calibration process to improve the accuracy of the estimate. If the carrier frequency and the sleep timer are locked to the same clock, the carrier frequency offset estimation and calibration information can be used to correct for the clock offset as well.
From the network perspective, the amount of traffic within the network can affect the rate of collisions among mobile nodes and consequently the throughput of the system and the power consumption at the mobile nodes (due to retransmissions). A dynamically adjusted Q factor masking scheme can be employed to optimize the random back-off time of nodes. This allows the network to settle into a good balance between network capacity and latency. Depending on the number of tag responses successfully received, the Q factor is dynamically adjusted to accommodate the network loading, thereby controlling the overall packet collision rate and reducing the retransmission of packets which leads to a lower power consumption at the mobile nodes. An embodiment of Q adjustment is illustrated in flow chart 40 , shown in FIG. 3 . In initial step 41 , the back-off time for each node is selected by a random number generator within the range from 0 to 2 Q−1 . Specifically, in step 42 , the base station sends out a beacon to start a query session. In step 43 , the base station determines the number of tag responses. If the number of tag responses is equal to the expected number, Q is kept as is for the next query session in step 42 . If the number of tag responses is less than the expected value, Q is decreased by a predetermined amount C, and is kept nonnegative, in step 45 for the next query session in step 42 . If the number of tag responses is greater than the expected value, Q is increased by a predetermined amount C, and upper bounded by a predetermined maximum number P, in step 45 for the next query session in step 42 .
FIG. 4 illustrates a wireless network system 50 for identification and location of mobile nodes by a base station. There are two types of nodes, base station nodes 51 a - 51 n and mobile nodes 52 a - 52 n . In one embodiment, at least one of mobile nodes 52 a - 52 n is at least 350 meters from a respective base station node 51 a - 51 n . Only one of base stations 51 a is the master base station node of system 50 providing the timing information for all nodes 52 a - 52 n within the network. All the other base stations 51 b - 51 n are slave base stations. Slave base stations 51 b - 51 n synchronize their timing to master base station 51 a while they hop with different hopping patterns from master base station 51 a . Slave base stations 51 b - 51 n broadcast their own beacons and have their own network of mobile nodes 53 a - 53 n . Mobile nodes 52 a - 52 n and 53 a - 53 n with enhanced capability can also act as base stations.
The present invention provides an approach for multiple base stations 51 a - 51 n to operate simultaneously and efficiently in proximity without causing interference to each other. Master base station 51 a can establish a frequency hopping network in an area by periodically sending out beacons 54 . Slave base stations 51 b - 51 n can operate in proximity by first establishing timing synchronization with master base station 51 a . To maintain coordination with the original master base station 51 a , slave base stations 51 b - 51 n reserve allocated time slots for the beacon transmission time of the master base station to prevent the mobile nodes from interfering with the beacon of the master station, as shown in FIG. 1 . By listening to beacons 54 of master base station 51 a beacon, slave base stations 51 b - 51 n can maintain their synchronization to master base station 51 a . Thus, the network timing of the slave network remains synchronized to the original master network. The beacon transmission maintains the network timing and operation. It is desirable to offset the beacon transmission time between the base stations to avoid collision of the beacons. Master base station 51 a can coordinate (assign) the beacon transmission times of slave base stations 51 b - 51 n . Slave base stations 51 b - 51 n have their own hopping patterns. These hopping patterns can either be mutually exclusive sets or have minimized probabilities of collision. The mutually exclusive set of hopping patterns can be achieved by using orthogonal hopping patterns. The orthogonal hopping patterns are employed when it is desirable to operate the system at or near its full capacity, but it places some constraints on the generation of the hopping sequence. For a lightly loaded network, i.e., the number of base stations in operation is a small fraction of the number of available frequency bins (channels) within the operational band, highly randomized hopping sequences can be adequate to reduce the number of collisions. In an alternate embodiment, more secure hopping sequences can be used. For example, slave base stations 51 b - 51 n broadcast beacons 55 to allow mobile nodes 53 a - 53 n to synchronize to them and establish their own networks. Slave base stations 51 b - 51 n are able to establish database 58 of the mobile node locations and the associated time tags. Slave base stations 51 b - 51 n can identify themselves to master base station 51 a by sending packets back to master base station 51 a in the same way as mobile nodes 52 a - 52 n to identify their profile to master base station 51 a.
Mobile nodes 52 a - 52 n and 53 a - 53 n can include a receiver and transmitter. In one embodiment, mobile nodes 52 a - 52 n are tags. Slave base stations 51 b - 51 n partition their time slots within a beacon period into two groups: contention access time slots 11 to allow mobile nodes to use the CSMA/CA scheme to respond; and allocated time slots 12 to allow slave base stations 51 b - 51 n to communicate with master base station 51 a for exchanging information, as shown in FIG. 1 . To communicate with master base station 51 a , slave base stations 51 b - 51 n use the contention access time slots to send a packet requesting master base station 51 a to assign allocated time slots for dedicated communication. Such request packets carry a request with a certain time slot offset and duration from beacon 54 of master base station 51 a . Upon receiving a grant from master base station 51 a , respective slave base stations 51 b - 51 n can start signaling to master base station 51 a during the allocated time slots.
Slave base stations 51 b - 51 n can communicate information they have received from mobile nodes 53 a - 53 n to master base station 51 a and can receive information about missing mobile nodes from master base station 51 a . By periodically exchanging such information, all base stations can share information about the locations of the mobile nodes. A new network established by the slave base station basically co-exists with the original master network without interference between the two networks. The two base stations can talk to one another and exchange information by using the allocated time slots. It is desirable to select nodes at strategically diverse locations to become the slave base stations to minimize collisions within the network. Some nodes with base station capability, but within proximity of another active base station, can simply join the network as a mobile node instead of acting as another base station. It can obtain the network database by downloading such information from the associated base station using the contention-free “allocated” time slot. This allows the overall system to remain stable and reasonably loaded while accommodating a large number of nodes with different requirements. The present invention distributes the traffic load and information among the nodes in a method utilizing the time, frequency, and space (geographic) domains intelligently and by adjusting the update rate (latency) of the system in a secure way.
The master base station differs from other base stations in two aspects: the master base station serves as the timing master for the network and the master base station serves as the information aggregator for the other base stations. Since the information is exchanged among the base stations, the system databases are duplicated among the base stations. If the master base station becomes non-operational for some reason, the overall network can continue to operate for a while without a master base station. The mobile nodes belonging to a non-operational master base station will automatically acquire one of the other base stations. The slave base stations will contend for the status as the master base station by transmitting at the same beacon time slot as the original master base station. If no collision occurs, the base station that succeeds in transmitting at that master base station slot will become the master station. If a collision occurs, the two or more base stations will back off a random number of hops before another attempt is made unless another base station acquires the status as master base station before that attempt. It is possible to give more capable stations a high probability of becoming the new master base station by giving them a lower (or zero) back off timer. This can be controlled by the original master base station by assigning different flags to the other base stations. Once one slave station becomes the new master base station, it immediately uses the allocated time slot for its original beacon in which it broadcasts to its mobile nodes to tell the mobile nodes the new beacon time slot to which they should switch. With this protocol, network survival is ensured.
If the slave base station is on the edge of the master base station coverage area and it can establish a communication link with the master base station, the network can extend its coverage area using the information exchange between the two base stations, as illustrated in FIG. 5 . By using additional base stations as slave base stations, the network can distribute the mobile nodes among the base stations. The base station distributes the mobile nodes to another base station by sending a command to selected mobile nodes. This way the overall system latency can be maintained since each base station only handles a limited number of mobile nodes. As shown in FIG. 5 , coverage area 60 is provided by base station 51 a . Various coverage ranges, 62 - 64 , are provided by base station 51 a , with range 63 covering tags 65 to 67 , and range 64 covering tags 68 to 71 . Tag 72 is still covered by base station 51 a , although it is farther than range 64 . Tags 73 and 74 are hidden from base station 51 a as they are outside its coverage area 60 . However, if tag 72 becomes a slave base station 51 b , its various ranges 75 and 76 can cover hidden tags 73 and 74 , since range 76 covers these tags. Thus, the range of base station 51 a has been extended with range extension 77 since it now includes the coverage area 78 of the slave base station 51 b.
It is desirable to have base stations at geographically diverse locations to reduce the rate of collisions within the system by taking advantage of the signal propagation loss at longer ranges as is conventionally used in a wide area cell phone system. Due to the full mobility of the system of the present invention, fixed location base stations are not fixed at strategic locations. In the present invention, the master base can regulate the establishment of slave base stations utilizing their locational information during the association process and control the “granting” of the slave base station status. Nodes that want to obtain system database 58 , shown in FIG. 4 , but are not granted base station status can act as mobile node to another base station and can request a download of system database 58 from the selected base station by using the contention-free allocated time slots, as shown in FIG. 1 .
In order to improve the power management process, mobile nodes can have their profiles represented by flags. Typically, the profile of a mobile node is pre-programmed and stored in the mobile node. A base station can also assign a flag to a mobile node and can issue a command addressed to a certain flag only. One benefit of grouping mobile nodes by flags is that commands can be addressed to mobile nodes with a specific flag. For example, mobile nodes that require less frequent updates are assigned a flag that indicates a longer duration power save mode. Mobile nodes that require more frequent updates are assigned a different flag corresponding to shorter duration power save mode. For a longer power save mode, the mobile nodes can skip several beacons before waking up. Thereby they conserve power and allow the network to be less congested. The use of multiple flags simultaneously can create a union or intersection of mobile nodes belonging to different groups.
FIG. 6 illustrates the concept of rate adaptation. The rate adaptation is typically applied to communication using allocated time slots only. Since contention-based time slots 11 are typically used to deal with short packets with small amounts of data, rate adaptation generally does not apply to these time slots. For allocated time slots 12 with large amounts of data to be transferred between nodes, it is more efficient to adapt to the highest possible data rate based on the relative received signal to noise level. The two nodes involved first exchange short signaling packets to establish the handshake for an agreed upon data rate within allocated time slot 12 . This handshake can be accomplished with the initiation node requesting a link report, which can include link margin, from the responding node, and the initiation node making a decision of which rate to use. Alternatively, the responding node can send a recommended rate to the initiation node, and the initiation node can “accept” or “reject” the recommendation. Once the rate decision is made, the new rate is employed and signaled in the packet header of the next message that is sent. Once the handshake is established, the information is exchanged at the agreed upon data rate for faster transfer. This information exchange must be stopped before the end of an allocated time slot.
FIG. 6 shows a communication network 80 that comprises base station 81 that is communicating with tags 82 to 92 . Tags 82 to 88 are within distance 93 of base station 81 , and therefore have a high signal to noise ratio and can operate at a high data rate. A faster physical rate results in a shorter slot for the same information to be transmitted than for tags at a greater distance. Tags 89 to 92 are located at a range greater than distance 93 , but less than distance 94 from base station 81 , and therefore have a lower signal to noise ratio and operate at a lower data rate. A slower physical rate results in a longer slot for the same information to be transmitted.
FIG. 7 illustrates a typical packet structure for base station beacon packet 95 , the mobile node response packet 96 , and base station acknowledgement (ACK) packet 97 . Base station beacon packet 95 design is optimized to save power for the mobile nodes while supporting other functions of the system. Base station beacon packet 95 comprises a preamble, which contains, for example, a 0,1,0,1 pattern and a frame sync (unique word or start frame delimiter) to allow the mobile nodes to establish receiver signal acquisition and synchronization. Following the preamble, the packet header contains information on the length of the packet and the signaling rate of the payload and the associated header CRC. The header information is the essential information for all the nodes within the system to determine the duration of the packet transmission and to avoid packet collisions. This is the essential part of CSMA/CA. The last part of the beacon carries payload information such as commands, requests, responses, allocated time slots, the hopping state, and other unicast or broadcast information.
It is to be understood that the above-described embodiments are illustrative of only a few of the many possible specific embodiments, which can represent applications of the principles of the invention. Numerous and varied other arrangements can be readily devised in accordance with these principles by those skilled in the art without departing from the spirit and scope of the invention.
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The present invention provides a method and system for establishing a highly mobile, long range secure wireless network with dynamic topologies and near full connectivity with acceptable latency using low cost, low power, compact and lightweight devices. One aspect of the system deals with a highly mobile network with dynamic network topologies and a time varying wireless medium that has neither absolute nor readily observable boundaries outside of which radio nodes are known to be unable to receive network frames, although the desirable open field boundary is 1 mile in radius from a base station node. A synchronous frequency hopping technique is used with mobile nodes that can become slave base station nodes to a master base station node to increase the effective range of the master base station without increasing the transmit power. Furthermore, the use of adjustable sleep times for the mobile nodes, as well as a novel clock calibration method, provides a substantial range increase with acceptable battery size and system latency.
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CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a continuation of U.S. patent application Ser. No. 11/589,512, filed on Oct. 30, 2006, which application claims the benefit of U.S. Provisional Patent Application No. 60/732,265 filed Oct. 31, 2005, the disclosures of which are hereby incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to orthopedic medicine, and more particularly to systems and methods for restricting relative motion between vertebrae.
Unfortunately millions of people experience back pain, and such is not only uncomfortable, but can be particularly debilitating. For example, many people who wish to participate in sports, manual labor, or even sedentary employment are unable to do so because of pains that arise from motion of or pressure on the spinal column. These pains are often caused by traumatic, inflammatory, metabolic, synovial, neoplastic and degenerative disorders of the spine.
In a normal spinal column, intervertebral discs that separate adjacent vertebrae from each other serve to provide stiffness that helps to restrain relative motion of the individual vertebrae in flexion, extension, axial rotation, and lateral bending. However, a damaged disc may provide inadequate stiffness along one or more modes of spinal motion. This inadequate stiffness may result in excessive relative vertebral motion when the spine is under a given load, as when the patient uses the muscles of the back. Such excessive relative motion may cause further damage to the disc, thereby causing back pain and ultimately, requiring replacement of the disc and/or other operations to decompress nerves affected by central, lateral or foraminal stenosis.
Heretofore, some stabilization devices have been proposed to restrict, but not entirely prevent, relative motion between adjacent vertebrae. These devices often contain linear springs that are too long to be easily positioned between adjacent vertebrae. Thus, they are often impossible to implant on motion segments where there is a short pedicle-to-pedicle displacement. Furthermore, known spinal implants typically have components that are either flexible, allowing limited relative motion between adjacent vertebrae, or rigid, providing fusion between vertebrae. Thus, they do not provide for interchangeability between flexible and rigid components. Accordingly, symptoms that would normally indicate stabilization and fusion of adjacent motion segments cannot be adequately treated, and vice versa. In other words, revision of an implant to provide fusion in place of stabilization is typically not feasible. Finally, many devices, when implanted in multiple levels along the spine, do not flexibly follow the natural curvature of the spine. Such devices may therefore cause discomfort, or restrict spinal motion in an unpredictable and unnatural manner.
Therefore, there exists a need for a system and method which corrects the above-noted shortcomings and allows for dynamic vertebral stabilization to restore normal movement and comfort to a patient.
SUMMARY OF THE INVENTION
A first aspect of the present invention is a stabilization system for controlling relative motion between a first vertebra and a second vertebra. In accordance with this first aspect, one embodiment stabilization system may include a first stabilizer having a first coupling adapted to be attached to a first anchoring member, a second coupling adapted to be attached to a second anchoring member and a resilient member configured to be coupled to the first and second couplings to transmit resilient force between the first and second couplings, the resilient member including a planar spring, wherein at least a portion of the planar spring flexes out-of-plane in response to relative motion between the vertebrae.
In other embodiments of the first aspect, the first stabilizer may further include a casing including a hollow first member and a hollow second member, wherein the resilient member is positioned within a cavity defined by engagement of the first and second hollow members. The resilient member is may also be positioned inside the casing such that the casing limits relative motion of the vertebrae by limiting deflection of the planar spring. The system may also include the first anchoring member and the second anchoring member, where the first and second anchoring members include a yoke polyaxially coupled to a fixation member implantable in a portion of either the first or second vertebra. The system may also include a first rigid connector including first and second couplings adapted to be attached to one of the first and second anchoring members, wherein the couplings are substantially rigidly connected together. In other embodiments, the path followed by the planar spring may be generally spiral-shaped, wherein the planar spring includes a central portion attached to the first coupling and a peripheral portion attached to the second coupling. The first stabilizer may further include a first articulation component configured to articulate to permit polyaxial relative rotation between one of the first or second couplings. The first articulation component may include a semispherical surface and a socket within which the semispherical surface is rotatable to permit polyaxial motion between the resilient member and the first anchoring member. The resilient member may be coupled to the first and second couplings such that the resilient member is able to urge the first and second couplings to move closer together and is also able to urge the couplings to move further apart.
The stabilization system may include a second component comprising a third coupling and a fourth coupling, wherein the third coupling is adapted to be attached to the first anchoring member such that the first anchoring member is capable of simultaneously retaining the first and third couplings. The second component may be a rigid connector, wherein the third and fourth couplings are substantially rigidly connected together, or the second component may be a second stabilizer comprising a second resilient member configured to exert resilient force between the third and fourth couplings.
Another aspect of the present invention is another stabilization system for controlling relative motion between a first vertebra and a second vertebra. In accordance with this second aspect, the stabilization system may include a first stabilizer having a first coupling adapted to rest within a yoke of a first anchoring member, a second coupling adapted to rest within a yoke of a second anchoring member, a resilient member coupled to the first and second couplings to transmit resilient force between the first and second couplings, the resilient member including a planar spring, wherein at least a portion of the planar spring flexes out-of-plane in response to relative motion between the vertebrae and a first articulation component configured to articulate to permit relative rotation between the first stabilizer and one of the first or second couplings.
Still another aspect of the present invention is a stabilization system for controlling relative motion between a first vertebra and a second vertebra. The stabilization system according to this aspect may include a first stabilizer having a first coupling adapted to be attached to a first anchoring member, a second coupling adapted to be attached to a second anchoring member, a resilient member configured to be coupled to the first and second couplings to transmit resilient force between the first and second couplings, the resilient member including a planar spring, wherein at least a portion of the planar spring flexes out-of-plane in response to relative motion between the vertebrae, a first articulation component configured to articulate to permit relative rotation between the first and second couplings and a first rigid connector including third and fourth couplings adapted to be attached to the first and second anchoring members, wherein the third and fourth couplings are substantially rigidly connected together.
Yet another aspect of the present invention is a method for controlling relative motion between a first vertebra and a second vertebra. In accordance with this aspect, the method may include the steps of positioning a planar spring of a first stabilizer attaching a first coupling of the first stabilizer to the first vertebra and attaching a second coupling of the first stabilizer to the second vertebra, wherein, after attachment of the couplings to the vertebrae, the planar spring is positioned to transmit resilient force between the vertebrae via flexure of at least a portion of the planar spring out-of-plane.
Yet another aspect of the present invention is another method for controlling relative motion between a first vertebra and a second vertebra. In accordance with this aspect, the method may include selecting a component selected from the group consisting of a first stabilizer and a first rigid connector, wherein the first stabilizer comprises a first coupling, a second coupling adapted to be attached to a second anchoring member secured to the second vertebra, a resilient member configured to transmit resilient force between the first and second couplings, and a first articulation component configured to articulate to permit relative rotation between the first and second couplings, wherein the first rigid connector comprises a first coupling and a second coupling substantially rigidly connected to the first coupling, attaching a first coupling of the selected component to a first anchoring member secured to the first vertebra and attaching a second coupling of the selected component to a second anchoring member secured to the second vertebra.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the subject matter of the present invention and the various advantages thereof can be realized by reference to the following detailed description in which reference is made to the accompanying drawings in which:
FIG. 1 is a perspective view of a dynamic stabilization assembly according to one embodiment of the invention.
FIG. 2 is an enlarged perspective view a stabilizer of the dynamic stabilization assembly of FIG. 1 .
FIG. 3 is an exploded perspective view of the stabilizer of FIG. 2 .
FIG. 4 is a further exploded perspective view of the stabilizer of FIG. 2 .
FIG. 5 is a partially exploded perspective view of the stabilizer of FIG. 2 having two end caps.
FIG. 6 is a perspective view of the stabilizer of FIG. 2 , illustrating attachment of one end cap to an end coupling.
FIG. 7 is a perspective view of the stabilizer of FIG. 2 with attached end caps.
FIG. 8 is a partially exploded perspective view of the dynamic stabilization assembly of FIG. 1 .
FIG. 9 is a perspective view of two of the stabilizers of FIG. 2 , placed end to end, with two end caps being detached therefrom.
FIG. 10 is a perspective view of two of the stabilizers of FIG. 2 , placed end to end, with two end caps being attached thereto.
FIG. 11 is a perspective view of two stabilizers of FIG. 2 , placed end to end, illustrating the coupling of the ends of the stabilizers to each other.
FIG. 12 is a perspective view of the stabilizer of FIG. 2 , coupled end-to-end with a second stabilizer for multi-level vertebral stabilization.
FIG. 13 is a perspective view of the two stabilizers of FIG. 12 , illustrating how the articulation components may be used to provide an overall curvature to the assembled modules.
FIG. 14 is a perspective view of the stabilizer of FIG. 2 , coupled end-to-end with a rigid connector and an end cap for single level vertebral joint stabilization with joint immobilization at an adjacent level.
FIG. 15 is an exploded perspective view of the stabilizer and rigid connector of FIG. 14 , illustrating the coupling of the stabilizer and the rigid connector to each other.
FIG. 16 is a perspective view of the stabilizer and rigid connector of FIG. 14 , illustrating how the articulation components may be used to provide an overall curvature to the assembled modules.
FIG. 17 is a perspective view of another dynamic stabilization assembly according to an alternative embodiment of the invention.
FIG. 18 is an enlarged perspective view of a stabilizer and end couplings of the dynamic stabilization assembly of FIG. 17 .
FIG. 19 is an exploded perspective view of the stabilizer of FIG. 18 .
FIG. 20 is an exploded perspective view of the stabilizer and end couplings of FIG. 18 .
FIG. 21 is a partially exploded perspective view of the dynamic stabilization assembly of FIG. 17 .
FIG. 22 is a perspective view of an overhung stabilizer and articulating component of an overhung dynamic stabilization assembly designed for shorter pedicle-to-pedicle displacements.
FIG. 23 is an exploded perspective view of the overhung stabilizer of FIG. 22 .
FIG. 24 is a partially exploded perspective view of an overhung dynamic stabilization assembly including the components of FIG. 22 .
FIG. 25 is another partially exploded perspective view of the overhung dynamic stabilization assembly of FIG. 24 .
FIG. 26 is a perspective view of a fully assembled overhung dynamic stabilization assembly of FIG. 24 .
FIG. 27 is a perspective view of the dynamic stabilization assembly including the stabilizer of FIG. 22 , along with the overhung stabilization assembly of FIG. 24 .
FIG. 28 is an exploded perspective view of the dynamic stabilization assembly of FIG. 27 .
FIG. 29 is a further exploded perspective view of the dynamic stabilization assembly of FIG. 27 .
DETAILED DESCRIPTION
The present invention relates to systems and methods for stabilizing the relative motion of spinal vertebrae. Those of ordinary skill in the art will recognize that the following description is merely illustrative of the principles of the invention, which may be applied in various ways to provide many different alternative embodiments. This description is understandably set forth for the purpose of illustrating the general principles of this invention and is not meant to limit the inventive concepts in the appended claims.
Referring to FIG. 1 , one embodiment of a single level dynamic stabilization system 10 is shown. The dynamic stabilization system 10 preferably includes a stabilizer 12 , a pair of fixation members 14 , a pair of yokes 16 securable to the fixation members 14 , and a pair of set screws 18 . The fixation members 14 , yokes 16 , and set screws 18 may be any of a variety of types known and available in the art, or may optionally be specially designed for operation with the stabilizer 12 . Each fixation member 14 with its corresponding yoke 16 and set screw provides an anchoring member 19 designed to anchor the stabilizer 12 to a pedicle or other portion of a vertebra (not shown). In the embodiments described and illustrated herein, the fixation members 14 are represented as pedicle screws. However, they could also be other types of screws fixed to other parts of the vertebrae, pins, clips, clamps, adhesive members, or any other device capable of anchoring the stabilizer to the vertebrae. Additionally, each yoke 16 may be unitarily formed with a fixation member 14 as illustrated herein, or each yoke 16 may be a separate entity and be polyaxially securable to a fixation member 14 .
The stabilizer 12 is illustrated alone in FIG. 2 . As shown in that figure, stabilizer 12 includes a central spring casing 22 , and a short arm 26 extending from the spring casing 22 on one side to an articulation component 24 . On the opposite side, a longer arm 27 extends from the spring casing 22 to another articulation component 25 . An end coupling 28 is also preferably located on the outside of each articulation component 24 , 25 . It is noted that the particular construction of stabilizer 12 depicted in FIG. 2 may vary. For example, the short arm 26 and longer arm 27 may be flipped to opposite sides.
Referring to FIG. 3 , an exploded view of the stabilizer 12 is shown, thereby illustrating the inner components of the stabilizer. For example, a planar spring 20 is shown encased within the spring casing 22 . The planar spring 20 is preferably coiled in a planar spiral-like shape and has a threaded inner ring surface 30 and an outer ring surface 32 . In addition, the spring casing 22 is made up of two concentric hollow members, an inner hollow member 40 and an outer hollow member 42 , with the planar spring 20 being disposed within the inner hollow member 40 . A circular bore 44 occupies the center of the inner hollow member 40 , creating a round opening from an inside surface 46 to an outside surface 48 . A protruding circular lip 49 may also surround the bore 44 where it exits the outside surface 48 . An inner wall 52 of the lip 49 is preferably threaded. Similarly, a circular bore 54 occupies the center of the outer hollow member 42 , creating a round opening from an inside surface 56 to an outside surface 58 . A protruding circular lip 59 may also surround the bore 54 where it exits the outside surface 58 .
Shown adjacent to the inner hollow member 40 is the short arm 26 , which has a threaded outer surface 76 on the end closest to the inner hollow member 40 . This end terminates at a flat end 36 . Both surface 76 and flat end 36 are best shown in FIG. 4 . On the opposite end of the short arm 26 is the articulation component 24 , which terminates at the end coupling 28 . Adjacent to the outer hollow member 42 is the long arm 27 , which has a threaded terminal segment 78 on the end closest to the outer hollow member 42 . The terminal segment terminates at a flat end 37 (best shown in FIG. 4 ). On the opposite end of the long arm 27 is the articulation component 25 , which terminates at the end coupling 28 .
When assembled, the short arm 26 fits inside the bore of the inner hollow member 40 . The threads on the outer surface 76 engage with the threads on the inner wall 52 , thereby securing the pieces together. As mentioned above, the planar spring 20 fits inside the inner hollow member 40 . In addition, the long arm 27 fits through the bore 54 of the outer hollow member 42 , with the threaded terminal segment 78 engaging the threaded inner ring surface 30 of the planar spring 20 . The inner hollow member 40 fits concentrically within the outer hollow member 42 , with the planar spring 20 also being disposed inside. Inside of the hollow members 40 , 42 , the flat ends 36 , 37 of the arms 26 , 27 are preferably adjacent to one another but not touching.
When assembled with the hollow members 40 , 42 and the arms 26 , 27 , the planar spring 20 can, if acted upon, flex out of the plane within which it is coiled. When the longer arm 27 , to which the planar spring 20 is engaged, moves toward or away from the short arm 26 , the spiral-like shape of the planar spring 20 preferably extends out of its plane. When the longer arm 27 returns to its original position, the planar spring 20 also preferably recoils back to its plane. During this extension and recoil, the inside surface 46 of the inner hollow member 40 , and the inside surface 56 of the outer hollow member 42 act as barriers to limit the movement of the planar spring 20 .
Use of the planar spring 20 , as opposed to a longer helical spring, keeps the overall length of the stabilizer 12 relatively short. In alternative embodiments, a planar spring according to the invention need not have a spiral-like shape, but can rather be a cantilevered leaf spring, a flexible disc, or the like. Further, in other alternative embodiments, a planar spring need not be used; rather, a different type of spring or a conventional helical spring may be used.
FIG. 4 illustrates the articulation components 24 , 25 in an exploded view. As is mentioned above, the articulation component 24 is located adjacent to and couples with the inner hollow member 40 , and the articulation component 25 is located adjacent to and couples with the outer hollow member 42 . Each articulation component 24 , 25 preferably comprises a semispherical surface 60 , a cup 62 , which are both enclosed by the end coupling 28 . The cup 62 is preferably dish shaped, with a cylindrical support wall 64 and two ends. On one end of the cup 62 is a depression 66 , and on the opposite side of the cup is a flat end 68 . The semispherical surface 60 preferably has a round side 70 which rotatably fits inside the depression 66 , so that each of the articulation components 24 , 25 thus takes the form of a ball-and-socket joint. The opposite side of each semispherical surface 60 is a connecting side 72 which narrows into a neck 74 . The neck 74 preferably widens into either the short arm 26 or the long arm 27 , which extends away from the semispherical surface 60 on the opposite side from the round side 70 . As is discussed above, the outer wall 76 of the short arm 26 is threaded, as is the terminal segment 78 of the long arm 27 . In alternative embodiments, articulation components may be omitted, or may be formed by any other type of mechanical joints known in the art.
The end coupling 28 has a support wall 102 which forms the outer sides of the cup, and a base 104 . A circular hole 106 occupies the center of the base 104 , and where the edge of the hole 106 meets the base 104 , a circular rim 108 preferably surrounds the hole 106 . The inside diameter of the rim 108 is preferably less than the diameter of the semispherical surface of the articulation components 24 and 25 , so that when assembled the semispherical surface 60 will fit into the end coupling 28 but not be capable of passing through the hole 106 . At the opposite end from the base 104 , the support wall 102 terminates in a flat edge 110 . Protruding from the edge 110 in the same plane as the support wall 102 , such that they form continuations of the support wall 102 , is a plurality of irregularly shaped teeth 112 . Between each tooth 112 and the adjacent tooth is a notch 114 .
When assembled, the round side 70 of each semispherical surface 60 rotatably rests in the depression 66 of the cup 62 , and the arm 26 or 27 extends away from the joining side 72 of the semispherical surface 60 . The generally cup-shaped end coupling 28 fits over each semispherical surface, arm and cup assembly. Each arm 26 , 27 extends from its semispherical surface 60 through its respective hole 106 . As described above, the arms then extend into the spring casing 22 , the long arm 27 connecting to the planar spring 20 and the short arm 26 connecting to the inner hollow member 40 . Rotation of either semispherical surface 60 results in movement of its arm 26 , 27 . When the short arm 26 moves, the flat end 37 of the opposite arm 27 may optionally contact the flat end 36 of the short arm 26 to acts as a stop to limit excessive movement. Similarly, when the long arm 27 moves, the flat end 36 of the opposite short arm 26 may stop excessive movement via contact with the flat end 37 of the long arm 27 . Thus the articulation components 24 , 25 secure the arms 26 , 27 in a rotatable manner to the spring casing 22 to permit the stabilizer 12 to obtain a variable curvature.
The assembled stabilizer 12 can be rotated into locking engagement with end caps or end couplings of other stabilizers for multi-level application. In fact, FIG. 5 illustrates one coupled stabilizer 12 , having a coupled end cap 120 and an uncoupled end cap 120 . Each end cap 120 preferably has a general cup-shape, much like each end coupling 28 . Each end cap 120 preferably includes a support wall 122 which forms the outer sides of the cup, and a solid base 124 which forms the bottom of the cup. The inside diameter of the end cap 120 is sized to fit around either arm 26 , 27 . At an opposite end from the base 124 , the support wall 122 terminates in a flat edge 130 . Protruding from the edge 130 in the same plane as the support wall 122 , such that they form continuations of the support wall 122 , are a plurality of irregularly shaped teeth 132 . Between each tooth 132 and the adjacent tooth is a notch 134 .
Referring to FIG. 6 , an end cap 120 is illustrated in partial engagement to a stabilizer 12 . When an end cap 120 is to be attached to an end coupling 28 , the end cap 120 is preferably lined up with the end coupling 28 so that the teeth 112 , 132 are pointed toward one another. The end cap 120 is then rotated and moved toward the end coupling 28 so that the teeth 132 fit into the notches 114 , while the teeth 112 fit into the notches 134 . When the teeth 112 , 132 are fully seated in the notches 114 , 134 such that the teeth 132 touch the edge 110 and the teeth 112 touch the edge 130 , the end cap 120 is further rotated until the teeth 112 , 132 interlock with each other and the end cap 120 is locked in place. A stabilizer 12 with two end caps 120 each fully engaged on opposite ends of the stabilizer 12 is depicted in FIG. 7 . In this depiction, the end caps 120 have been fully rotated so that the teeth 132 of the end caps 120 are interlocked with the teeth 112 of both end couplings 28 .
FIG. 8 shows an exploded view of the dynamic stabilization system 10 with a fully assembled stabilizer 12 , two anchoring members 19 with yokes 16 and fixation members 14 , and two set screws 18 . In this design, each fixation member 14 preferably has a pointed end 140 which aids in screwing the member into a corresponding vertebra when implanted. The opposite end of the fixation member 14 is preferably unitarily formed with a U-shaped yoke 16 , so that the bottom of the U is a head 142 of the fixation member 14 . Each yoke 16 has two curved opposing support walls 144 . Alternating between the support walls 144 are two opposing gaps 146 , which form a cavity 148 therebetween that occupies the interior of the yoke 16 . The inner surfaces 150 of the support walls 144 are also preferably threaded to engage a set screw 18 .
According to the embodiment depicted, in use, the stabilizer 12 is inserted into the yokes 16 of two anchoring members 19 whose fixation members 14 have previously been anchored in the pedicles, or other portion, of the corresponding vertebrae. The stabilizer 12 is laid lengthwise into the yokes 16 such that the long axis of the stabilizer 12 is perpendicular to the long axes of the fixation members 14 , and so that the spring casing 22 lies between the anchoring members 19 . Each end coupling 28 /end cap 120 pair preferably rests on the head 142 within the cavity 148 . Each end cap preferably occupies the gaps 146 , and the two articulation components 24 , 25 lie adjacent to, but outside of, the two interior gaps 146 .
The end couplings 28 and attached end caps 120 are preferably secured within the yokes 16 of the anchoring members 19 through the use of the set screws 18 . One set screw 18 is screwed into the top of each yoke 16 so that its threads engage with the threaded inner surfaces 150 of the support walls 144 . The set screws 18 are then tightened to hold the stabilizer 12 in place. As described above, an alternative embodiment of the invention includes yokes 16 which are separate entities from the fixation members 14 , and are polyaxially securable to the fixation members 14 . If such separate polyaxially securable yokes 16 are included, tightening of the set screws 18 may also press the end couplings 28 and end caps 120 against the heads 142 of the fixation members 14 , thereby restricting further rotation of the polyaxially securable yokes 16 with respect to the fixation members 14 to secure the entire assembly. Those of ordinary skill in the art would readily recognize this operation.
Referring to FIG. 9 , two assembled stabilizers 12 are illustrated positioned end-to end with two end caps 120 positioned at the outer ends of the stabilizers 12 . Two stabilizers 12 may be interlocked with each other end-to-end and implanted when it is desirable to stabilize the relative motion of three adjacent vertebrae. FIG. 10 depicts a similar assembly, with two stabilizers 12 being illustrated end-to-end, and one end cap 120 being secured to each outer end coupling 28 in a similar fashion to that previously depicted in FIG. 7 . On the inner ends of each stabilizer 12 , the teeth 112 of each end coupling 28 are aligned to fit into the notches 114 of the facing end coupling 28 . FIG. 11 depicts the two stabilizers 12 in an end-to-end fashion and partially interlocked together. The teeth 112 of each facing end coupling 28 are in the notches 114 of the opposite end coupling 28 , and the stabilizers 12 have been partially turned so that the teeth 112 are partially interlocked. In FIG. 12 , the two stabilizers 12 are shown completely interlocked end-to-end. The end couplings 28 of the two stabilizers 12 are rotated into locking engagement with each other and an end cap 120 is locked onto each unoccupied external end coupling 28 . The entire dynamic stabilization assembly has four articulation components 24 , 25 , which will permit considerable differentiation in orientation between the three fixation members 14 that would be used to attach the stabilizers 12 to three adjacent vertebrae (not shown). In fact, in FIG. 13 , two interlocked stabilizers 12 are illustrated with the articulation components 24 , 25 in an articulated position so that the stabilizers 12 no longer lie in a straight line, but instead the multi-level dynamic stabilization assembly approximates a curve. This enables the assembly to conform to the desired lordotic curve of the lower spine or to other spinal curvatures, such as those caused by or used to correct scoliosis. Additional levels can be added if desired.
Referring to FIG. 14 , a stabilizer 12 is depicted secured end-to-end to a rigid connector 160 to provide dynamic stabilization across one level, and posterior immobilization and/or fusion across the adjacent level. The rigid connector 160 has a rod 162 and an end coupling 164 . The end coupling 164 is toothed and notched so that it may engage the end coupling 28 on the stabilizer 12 . This is not unlike the other couplings discussed above. In addition, and like that discussed above, the rod 162 may be secured in the yoke 16 of a fixation member 14 with a set screw 18 . Similarly, the interlocked end coupling 164 /end coupling 28 combination may be secured in the yoke 16 of an anchoring member 19 in a manner similar to the previously described securing of the end couplings and end caps. Additional rigid connectors 160 or stabilizers 12 with associated anchoring members 19 can be added if additional levels are desired.
FIG. 15 depicts an exploded view of the system depicted in FIG. 14 , having one stabilizer 12 , an end cap 120 , and one rigid connector 160 . The end coupling 164 has teeth 166 protruding from one end, and notches 167 between the teeth. When the rigid connector 160 is attached to the stabilizer 12 , the teeth 166 of the end coupling 164 fit into the notches 114 of the end coupling 28 . Simultaneously, the teeth 112 of the end coupling 28 fit into the notches 167 of the end coupling 164 . The stabilizer 12 and the rigid connector 160 are rotated in opposite directions so that the teeth 112 , 166 interlock and the stabilizer 112 and the rigid connector 160 are locked together. The end cap 120 is interlocked onto the remaining open coupling 28 of the stabilizer 12 as previously described. FIG. 16 depicts one stabilizer 12 interlocked with a rigid connector 160 and an end cap 120 , and in a position with components 24 , 25 being articulated to allow the assembly to approximate a curve.
Thus, like the above described systems, dynamic stabilization across one level and posterior immobilization and/or fusion across the adjacent level may be accomplished while simultaneously following the desired curvature of the spine. In some cases, it may be desirable to allow immobilization and/or fusion across one level, and dynamic stabilization across the adjacent level on each end. In such a case, a rigid connector 160 with an end coupling 164 at each end could be used, allowing a stabilization module 12 to couple to each end of the rigid connector 160 .
Referring to FIG. 17 , an alternative embodiment of a stabilization system 168 is depicted. In this system, a stabilizer 170 is secured to two anchoring members 19 . As in the previous embodiment, the anchoring members 19 each preferably include two yokes 16 connected with two fixation members 14 , and two set screws 18 are preferably used to hold the stabilizer 170 in place.
As seen in FIG. 18 , the stabilizer 170 has a spring casing 172 and two articulation components 174 , 175 . A two-piece end housing 178 also preferably extends from either articulation component 174 , 175 . As shown in FIG. 19 , the spring casing 172 preferably houses a planar spring 180 . The planar spring 180 has a first side 182 and a second side 183 . Extending from the first side 182 is an arm 184 which narrows into a neck 186 and terminates in a semispherical surface 188 . The spring casing 172 has an outer hollow member 190 and an inner hollow member 192 . The inner hollow member 192 is of a shallow dish shape, and has a circular plate 194 which forms the base of the hollow member, with a threaded outer rim 196 which encircles the outside of the plate 194 . An inner rim 198 encircles a round hole 200 in the center of the plate 194 .
Similarly, the outer hollow member 190 is of a deep dish shape with an interior cavity 202 . It has a circular plate 204 which forms the base of the hollow member, and a support member 206 which forms the side wall of the hollow member. An inner surface 208 of the support member 206 is threaded, but a neck 210 extends from the outside of the plate 204 and terminates in a semispherical surface 212 . This latter element is different from both inner hollow member 192 and that which is included in the above described embodiments of the present invention.
When assembled, the planar spring 180 preferably fits into the cavity 202 of the outer hollow member 190 , with the second side 183 adjacent to the plate 204 of the hollow member 190 . The inner hollow member 192 fits over the planar spring 180 , so that the arm 184 and the semispherical surface 188 extend through the hole 200 in the inner hollow member 192 . Thereafter, the threads on the outer rim 196 engage with the threads on the inner surface 208 of the outer hollow member 190 , joining the hollow members 190 , 192 to form the casing 172 . The spring 180 is thusly captured inside the casing 172 , which prevents it from moving axially. When the arm 184 moves toward or away from the outer hollow member 190 , the planar spring 180 extends out of its plane. When the arm 184 returns to its original position, the planar spring 180 recoils back towards its plane. During this extension and recoiling, the plate 194 of the inner hollow member 192 and the plate 204 of the outer hollow member 190 act as barriers to limit the movement of the planar spring 180 . The arm 184 is encircled by the inner rim 198 , which acts as a bearing surface to prevent radial movement of the arm relative to the inferior hollow member 192 .
As seen in FIG. 20 , a coupling in the form of a two-part end housing 178 fits over each semispherical surface 188 , 212 . Each end housing 178 has a first wall 220 and a second wall 222 . The first wall 220 is shaped like a segment of a cylindrical body that is split lengthwise, and has an inner surface 224 and rounded outer surface 226 . At each lengthwise end of the first wall 220 , a rounded first hollow 228 is indented into the inner surface 224 . Indented into the inner surface 224 , between the hollows 228 , are two receiving holes 230 . The second wall 222 is also shaped like a segment of a cylindrical body and has an inner surface 234 and an outer surface 236 . Unlike the first wall 220 , the outer surface 236 is not rounded but is squared off so it is flat. The inner surface 234 has a rounded second hollow 238 indented into each lengthwise end. Each pair of rounded hollows 228 , 238 cooperates to define a socket sized to receive the corresponding ball 188 or 212 . Two pin holes 240 extend from the outer surface 236 through the wall 222 to the inner surface 234 , such that two pins 242 can fit through the pin holes 240 and into the receiving holes 230 in the first wall 220 . The pins 242 and receiving holes 230 releasably hold the walls 220 , 222 together around the semispherical surfaces 188 , 212 , and prevent shearing of the walls. In other embodiments of the invention, the pins 242 and receiving holes 230 could be replaced by posts and brackets, or a snap mechanism or other mechanisms capable of releasably joining the walls 220 , 222 .
The assembled stabilizer 170 fits into the yokes 16 of two anchoring members 19 , as is best shown in FIG. 17 (shown disassembled in FIG. 21 ). In the fully assembled state, the end housings 178 are preferably situated perpendicular to the fixation members 14 , so that the end housings 178 fit between support walls 144 of anchoring member 19 , and the rounded outer surface 226 is cradled on a curved floor 142 between walls 144 . Two set screws 18 are thereafter engaged in the threads 150 and tightened. The tightening of the set screws 18 creates pressure on the end housings 178 , holding the housings closed around the semispherical surfaces 188 , 212 . As described in the previous embodiment, each anchoring member 19 may comprise a unitary piece which includes both the fixation member 14 and the yoke 16 , or the fixation member 14 and the yoke 16 may be separate pieces. In such an embodiment where the fixation member 14 and yokes 16 are separate pieces, tightening of the set screws 18 may also press the end housings 178 against the heads 142 of the fixation members 14 , thereby restricting further rotation of the yokes 16 with respect to the fixation members 14 to secure the entire assembly.
Like the above embodiment, two stabilizers 170 can be secured end-to-end in accordance with this latter embodiment. When two stabilizers 170 are to be used together, the stabilizers are partially assembled as shown in FIG. 19 and described previously. The semispherical surface 212 or 188 from one stabilizer 170 is preferably placed in the empty hollow 228 of the first wall 220 of the second stabilizer 170 before the second wall 222 is joined to the first wall 220 . When the second wall 222 is joined to the first wall 220 , the semispherical surfaces 212 , 188 are captured in the socket sections 228 , 238 and the modules are joined. A stabilizer 170 can also be employed in combination with a rigid connector to provide dynamic stabilization across one level and posterior fusion across the adjacent level. Additional levels may be added as desired. Multiple stabilization/fusion levels can include two or more sequential rigid connectors, or rigid connecters sequentially interspersed with stabilizers.
Referring to FIG. 22 , a portion of an “overhung” dynamic stabilization system is shown. This system can be used when an offset between adjacent fixation members is desired and/or when a short pedicle-to-pedicle displacement must be accommodated. In this embodiment, a stabilizer 250 includes a housing 252 , an articulation component 254 and an arm 256 which extends from the joint. A tunnel 258 provides an opening for placement of the stabilizer 250 over an anchoring member (best shown in FIG. 26 ), and two set screws 259 are used to press a flexible stop 260 against the anchoring member, securing the stabilizer 250 in place.
FIG. 23 depicts an exploded view of the stabilizer 250 in more detail. As shown in that figure, the housing 252 has a chamber 262 which holds the articulation component 254 . A threaded cap 264 is screwed into the housing 252 closing off one end of the chamber 262 . A planar spring 266 with a threaded inner ring 268 is positioned within the cap 264 . Releasably screwed to the inner ring 268 is a socket 270 with a threaded end stud 272 . A cup 274 terminates the socket 270 at the end opposite the threaded end stud 272 . A semispherical surface 276 is connected to the arm 256 , and the semispherical surface 276 rotatably rests in the cup 274 . A tubular sleeve 278 surrounds the socket 270 , semispherical surface 276 and arm 256 . The sleeve 278 has a central bore 280 through which the arm 256 protrudes. The sleeve 278 also has two grooves 282 which run lengthwise down opposite outer sides of the sleeve. When the sleeve 278 , along with the enclosed socket 270 , semispherical surface 276 and arm 256 are in the chamber 262 , the sleeve is held in place by two pins 284 . The pins 284 are inserted through two pin holes 286 which perforate the outer wall of the housing 252 . The inserted pins 284 fit into the grooves 282 , and prevent the sleeve 278 and its enclosed contents from moving axially.
An unassembled stabilization system 248 is shown in FIG. 24 . The system 248 includes the overhung stabilizer 250 , an anchoring member 19 , an anchoring member 288 , an articulation component 24 , an end coupling 28 and an end cap 120 . As described in previous embodiments, the anchoring member 19 has a fixation member 14 , a yoke 16 and a set screw 18 . The anchoring member 288 comprises a fixation member 14 and an extension post 290 . Once again, the fixation members 14 may comprise pedicle screws, screws fixed to other parts of the vertebrae, pins, clips, clamps, adhesive members, or any other device capable of anchoring the stabilizer to the vertebrae. Additionally, each yoke 16 may be unitarily formed with a fixation member 14 as illustrated herein, or each yoke 16 may be a separate entity and be polyaxially securable to a fixation member 14 . The articulation component 24 has a tubular joining arm 292 extending from an end coupling 28 . The joining arm 292 is shaped to fit over the end of the arm 256 which protrudes from the articulation component 254 .
FIG. 25 illustrates the stabilization system 248 in a partially assembled state. The stabilizer 250 is joined to the articulation component 24 and end coupling 28 , with the joining arm 292 fitting over the end of the arm 256 which protrudes from the articulation component 254 through the use of a press fit or other attachment mechanism. The end cap 120 fits on the opposite end of the end coupling 28 , in the manner previously described. The fully assembled stabilization system 248 is shown in FIG. 26 . In this assembly, the end coupling 28 and end cap 120 fit in the yoke 16 of the anchoring member 19 , and are held in place by tightening the set screw 18 , in the same manner set forth previously. The assembled stabilizer 250 is placed over the anchoring member 288 , with the extension post 290 on the anchoring member 288 extending posteriorly through the tunnel 258 . The set screws 259 are engaged in the outer wall of the housing 252 adjacent to the extension post 290 . When the set screws 259 are tightened, they push against the flexible stop 260 , which in turn pushes against the post 290 , holding the stabilizer 250 in place on the extension post 290 . Finally, the joining arm 292 connects the articulation component 24 to the articulation component 254 , thus pivotably connecting the stabilizer 250 , secured to the anchoring member 288 , to the anchoring member 19 .
When the system 248 is fully assembled and anchored to two adjacent vertebrae, motion between the two vertebrae can cause the planar spring 266 to flex out of its plane. Referring back to FIG. 23 , when the two adjacent vertebrae move closer together and the distance between them shortens, the planar spring 266 returns to its plane. When the two adjacent vertebrae move apart and the distance between them lengthens, the planar spring 266 flexes in the opposite direction along the spiral path, toward the sleeve 278 . As the planar spring 266 flexes, the sleeve 278 which holds the articulation component 254 slides along the chamber 262 . The grooves 282 allow the sleeve 278 to slide back and forth past the pins 284 , but the pins 284 restrict axial movement of the sleeve 278 and serve as stops to prevent the sleeve 278 from moving completely out of the chamber 262 .
Referring to FIG. 27 , a multi-level dynamic stabilization system is shown which includes a stabilizer 12 as per FIGS. 1-8 , and an overhung stabilizer 250 as per FIGS. 22-26 . The stabilizer 12 is mounted on two anchoring members 19 and connected via the joining arm 292 to the overhung stabilizer 250 which is mounted an anchoring member 288 . The resulting dynamic stabilization system provides stabilization across two adjacent vertebral levels. The overhung stabilizer 250 allows one of the levels to have a relatively short pedicle-to-pedicle displacement. FIG. 28 illustrates the stabilizers 12 , 250 , two anchoring members 19 and one anchoring member 288 in an exploded view. Each anchoring members 19 includes a fixation member 14 , a yoke 16 and a set screw 18 , as set forth previously. The anchoring member 288 includes a fixation member 14 with an extension post 290 , as set forth previously.
Referring to FIG. 29 , the stabilizers 12 , 250 and the anchoring members 19 , 288 are shown in a further exploded view. The stabilizer 12 has two end couplings 28 , one end coupling 28 connecting with one end cap 120 thereby forming a coupling mountable in a yoke 16 . The second end coupling 28 of the stabilizer 12 preferably couples with the end coupling 28 that connects to the joining arm 292 , forming a coupling mountable in another yoke 16 . The joining arm 292 fits over the arm 256 of the stabilizer 250 , thus connecting the stabilizer 250 to the stabilizer 12 . The stabilizer 250 is mountable on the anchoring member 288 , in the manner set forth previously. When assembled, this two level system has two articulation components 24 , one articulation component 25 , and one articulation component 254 , providing pivotability between the stabilized vertebrae. Additionally, an overhung stabilizer 250 , a stabilizer 12 , and/or a stabilizer 170 such as that depicted in FIGS. 17-21 can be implanted in combination with a rigid connector 160 such as that depicted in FIGS. 14-16 .
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.
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An intervertebral stabilization device and method is disclosed. The device preferably includes a planar spring enclosed within a housing. The housing is joined to an articulation component at either end, and the articulation components have couplings connectable to anchoring components which are securable to adjacent vertebrae. The planar spring can flex and retract providing relative motion between the adjacent vertebrae. The articulation components are ball and socket joints which allow the entire assembly to flexibly follow the curvature of the spine. A fusion rod with articulation components and couplings at either end may be substituted for the spring device. The couplings enable interchangeability between a fusion rod assembly and spring assembly, so that dynamic stabilization can occur at one vertebral level and fusion at the adjacent vertebral level. An overhung spring assembly with a sideways displaced housing which allows for a shorter pedicle to pedicle displacement is also disclosed.
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The present invention relates generally to stage lighting and particularly to color indicia for stage lighting control consoles.
BACKGROUND OF THE INVENTION
In a typical stage lighting control system a lighting control console is located with a view toward the stage and different colored stage lights illuminate the stage. The control console includes individual light control devices, or faders, for operation of corresponding stage lights. The operator thereby illuminates the stage in selected light colors to achieve a desired stage lighting effect.
For a given stage arrangement, each stage light is directed toward a portion of the stage and a color filter, or gel, is mounted to provide a desired lighting color. The stage lights are operatively connected to the control console and each fader controls one or more associated stage lights. The operator associates each fader with a given colored stage light by notation written on adhesive tape lying next to the fader. Thus, various color names are written across the adhesive tape in accordance with the current stage arrangement.
During a stage performance the operator provides a variety of lighting scenes in coordination with the stage performance, and this can be challenging. Lighting control consoles can have as many as ninety faders in each bank. There are over two hundred standard stage light gels colors, and additional colors are possible by overlaying gels. Also, with slight variations between similar colors, it is difficult to distinguish, by crowded written notion on adhesive tape, subtle differences between similar colors. To provide a given lighting scene a particular combination of fader settings is needed; the operator must read the adhesive tape notation to identify stage lights requiring adjustment and adjust the corresponding faders. In many cases scenes change rapidly. The operator must quickly identify and adjust the faders to preserve coordination with the stage performance.
Given experience with a particular stage arrangement and performance, an operator of the lighting control console becomes adept at manipulating the faders to move from scene to scene. However, performances and lighting arrangements change. The fader labels on the adhesive tape are often rewritten. Even experienced operators are faced with new fader labels. Also, experienced operators are not always available. It is therefore desirable that the operator be able to quickly and reliably associate faders with the stage lights, despite unfamiliarity with the current stage arrangement.
Some stage lighting control consoles are programmable. A particular combination of fader settings, a lighting scene, is stored by first setting the faders as desired and then invoking an automatic procedure which reads the fader settings and writes corresponding values into a memory device. A number of scenes can be loaded into the console for later recall during a stage performance. Even a programmable lighting control console requires that the user label the faders by notation on adhesive tape for a given stage arrangement and step through each scene to be presented during the performance. Efficient use of a programmable lighting control console requires the operator to quickly identify and adjust the faders to move from scene to scene during programming.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a method and apparatus for quickly and reliably adjusting a lighting control console. Operators unfamiliar with a given stage arrangement can more quickly master new fader assignments.
It is a further object of the present invention to provide an accurate indication of the stage light color associated with a given fader. The operator thereby distinguishes between subtle color differences.
The foregoing objects and advantageous are achieved by a lighting control console having display elements corresponding in color to the color of the stage light controlled by an adjacent fader. The operator need not read crowded notation on adhesive tape, stage light colors associated with each fader are determined precisely by quick inspection.
According to one aspect of the present invention, the colored console display elements include a light source and gels of the same or similar material as used on the corresponding stage lights. The light provided by each display element is very close in color to the light provided by the corresponding stage light. This enables the operator to easily distinguish subtle color differences.
In a second aspect of the present invention, the colored display elements are replaceable. The lighting control console is thereby easily re-configured for each new stage arrangement.
In one embodiment of the present invention, a lighting control console display includes colored display elements integral to the console and adjacent corresponding faders. Each colored display element includes a light source varying in intensity with the intensity of the corresponding stage light, and a gel similar to that on the corresponding stage light. As the operator adjusts the faders, the corresponding display elements provide both color and intensity information.
In a second embodiment of the present invention, a lighting control console display includes a light conductive element adapted to receive a light source. The display is positioned adjacent the faders with gel strips mounted to the light conductive element. The gel strips correspond in color to the associated stage light, and correspond in position to the faders. When the light source is activated, light carried by the light conductive element passes through the gel strips and provides the desired color indica. This embodiment may be incorporated into a preexisting lighting control console by adaptation to common console light sources.
The subject matter of the present invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. Both the organization and method of operation of the invention, together with further advantages and objects thereof, however, may best be understood by reference to the following description and accompanying drawings wherein like reference characters refer to like elements.
DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a stage lighting system including a lighting control console with an integrated color display according to the present invention;
FIG. 2 is a cross sectional view of the lighting control console of FIG. 2 taken along lines 2--2 of FIG. 1;
FIG. 3 is a cross sectional view, taken along lines 3--3 of FIG. 1, showing mechanical details of the display of FIG. 1;
FIG. 4 is a diagram of a control circuit for the display of FIG. 1;
FIG. 5 illustrates a second color display according to the present invention adapted for use in with preexisting lighting control consoles; and
FIG. 6 is a cross sectional view of the color display of FIG. 5 taken along lines 6--6 of FIG. 5;
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates a stage lighting control system having a lighting control console 12 located with a view toward a stage 10. Colored stage lights 14, individually numbered 14a-14i, illuminate stage 10. A multi-stand cable 17 connects console 12 to a dimmer pack 19 for applying control signals thereto. Dimmer pack 19 connects by way of multi-stand cable 18 to stage lights 14 for applying power to stage lights 14 in accordance with control signals received from console 12. An operator of console 12 manipulates stage lights 14 in coordination with a stage performance. Console 12 includes individual light control devices or faders 16, individually numbered 16a-16i, for operation of corresponding stage lights 14a-14i. For example, as fader 16a is moved toward stage 10 the intensity of stage light 14a increases, and as fader 16a is moved away from stage 10 the intensity of stage light 14a decreases. It will be understood that for any given stage arrangement the lights 14 may be positioned in any arbitrary pattern and the corresponding faders 16 would not necessarily correspond in position to the position of stage lights 14. Accordingly, it is necessary for an operator of console 12 to be able to associate a given fader 16 with the corresponding stage light 14.
Console 12 includes a display 20 having colored display elements, individually numbered 20a-20i, adjacent corresponding faders 16a-16i. Each display element 20 corresponds in color to that of the stage light controlled by the adjacent fader 16. The operator of console 12 thereby quickly determines the color of the stage light controlled by each fader 16.
With reference to FIG. 2 in conjunction with FIG. 1, each display element 20 includes a light source 22 and a gel strip 24. FIG. 2 illustrates in cross section the display element 20c including the source 22c and the gel strip 24c, however, it will be understood that display elements 20 are each similar to element 20c as shown. As will be described in greater detail hereafter, each light source 22 is operatively coupled to the corresponding fader 16 whereby operation of each fader 16 causes variation in intensity of both the stage light 14 controlled by the fader 16 and the corresponding light source 22. The gel strips 24 are cut from the same or similar material as used on the corresponding stage light 14, i.e., the stage light controlled by the adjacent fader 16. Thus, light emitted by each display element 20 is very close in color to the light emitted by the corresponding stage light 14.
The display 20 includes a frame 30 attached to the face 32 of console 12 by a hinge 34. A protective plastic or glass panel 36 mounts to frame 30 and serves as the top surface of display 20. Gel strips 24 mount behind panel 36 in spaced relation corresponding to the spaced relation of faders 16. Gel strips 24 so mounted to frame 30 are positioned adjacent corresponding faders 16. Placing the hinge 34 at the lower edge of frame 30, i.e., closest to the operator, shields the operator from the unfiltered glare of light sources 22 when frame 30 is pivoted to its open position as shown in phantom in FIG. 2. With frame 30 in its open position, the gel strips 24 are removable and remountable on frame 30. Thus, display 20 is easily re-configured for a new stage arrangement by re-arrangement or replacement of gels 24.
With reference to FIG. 3, showing frame 30 in cross section, frame 30 includes an aluminum base plate 38 with an upper surface 42. Rectangular recesses cut into the base plate 38 from the upper surface 42 are defined by recess walls 40. Panel 36 is bonded to upper surface 42 leaving gel strip retention spaces 44, individually numbered 44a-44i, as defined by panel 36 and recess walls 40 of base plate 38. Retention spaces 44a-44i correspond in position to the associated faders 16a-16i, respectively. A gel strip 24, having dimensions corresponding to a retention space 44, may then be positioned adjacent each fader 16. Base plate 38 is provided with view apertures 45a-45i located intermediate of corresponding light sources 22a-22i and retention spaces 44a-44i, respectively. Thus, light emitted by sources 22 passes through the corresponding view apertures 45 and gels 24. Each display element 20 thereby provides light corresponding in color to the color of the gel 24 mounted in the corresponding retention space 44.
Base plate 38 is attached to hinge 34 whereby the frame 30, including mounted gel strips 24, pivots as shown in FIG. 2. Hinge 34 and frame 30 pivot into an opening 46 in console 12 with a stop 48 (FIG. 2) positioned to hold the upper surface of panel 36 flush with the upper surface of console 12. This mounting arrangement retains each gel strip 24 within the corresponding retention space 44 while the frame 30 is closed, and allows removal of gel strips 24 when frame 30 is opened.
FIG. 4 illustrates a control circuit for display 20. The light source 22 of each display element 20 is connected in series with a corresponding potentiometer 50, individually numbered 50a-50i. A first terminal of each light source 22 connects to the positive lead 52 of a variable voltage source 54. The second terminal of each light source 22a-22i connects to the stationary terminal of the corresponding potentiometer 50a-50i, respectively. The movable terminal of each potentiometer 50 connects, through a corresponding limiting resister 56a-56i, respectively, to the negative or common terminal 58 of voltage source 54. Thus, potentiometers 50 individually control the intensity of the corresponding light sources 22.
A dimmer control knob 60 (FIGS. 1 and 4) determines the output of variable voltage source 54. By suitably selecting component values and the voltage range of source 54, knob 60 may be used to raise the output of power supply 54 to bias the control circuit and provide a minimum output for light sources 22. Thus, even when a potentiometer 50 is positioned to turn off the associated stage light, the corresponding display element 20 will be illuminated. The operator is then able to determine stage light colors even when the stage light is off. Also, by adjustment of knob 60 the output of source 54 may be lowered to eliminate the minimum output of light sources 22. In such condition, only light sources 22 corresponding to currently activated stage lights 14 are illuminated. In either case, intensity variation of each light source 22 corresponds to intensity variation of the corresponding stage light 14.
To accomplish the primary function of controlling stage lights 14, console 12 would include circuit elements (not shown) for producing and applying stage light control signals to dimmer pack 19. Such circuit elements might include a second set of potentiometers corresponding to potentiometers 50a-50i, each physically coupled to the corresponding potentiometer 50 for movement therewith. The second set of potentiometer would control the intensity of corresponding stage lights 14 whereby variations in intensity of stage lights 14 would be matched by variations in intensity of light sources 22. Alternatively, a high input impedance device, such as the gate of a transistor, could be attached at the interconnection of each light source 22 and the corresponding potentiometer 50. Such transistors could then be used in a circuit to control the intensity of the stage lights. However, it would be necessary to account for variations in the voltage source 54 directed toward biasing of the display control circuit shown on FIG. 3. In any event, the incorporation of a display device having individual light sources varying in intensity with the intensity of the corresponding stage light may take many conventional forms, all of which are considered within the scope of the present invention.
FIG. 5 illustrates a second embodiment of the present invention adapted for use in conjunction with preexisting lighting control consoles. In FIG. 5, a display 80 includes colored display elements, individually numbered 80a-80i. The display elements 80a-80i correspond in color to the stage lights 14a-14i and in position to the faders 16a-16i of console 81. Thus, the display 80 may be placed on the surface of console 81 adjacent faders 16 with each display element 80a-80i positioned adjacent a corresponding fader 16a-16i, respectively. An operator of console 81 is then able to quickly associate each fader 16 with a corresponding stage light 14 by quick inspection of display 80.
Display 80 includes a shield 82 adapted to couple to a light source 84. Light source 84 may be a preexisting light source of console 81, or may be incorporated into the display 80 in conventional fashion. A common preexisting light source 84 found on many lighting control consoles includes a light source 86 mounted on the distal end of a flexible support 88. The light source 84 includes a dimmer knob 90 for controlling the intensity of light source 86. Light source 84 also includes a mounting structure 92 upon which the light source 86 mounts. Shield 82 is adapted to couple to the structure 92 in order to receive the light source 86 therein. Thus, display 80 is adapted to couple to a preexisting light source of a lighting control console.
Display 80 also includes an acrylic rod 96 serving as a light conducting element. Shield 82 mounts to an end of rod 96 whereby light emitted from source 86 enters that end of rod 96 and is carried along the length of rod 96. A cap 98 mounts to the opposite end of rod 96 and includes a reflective surface 100 abutting the end face of rod 96. Thus light entering rod 96 from source 86 travels along the length of rod 96 and reflects at the distal end of rod 96. It has been found that by polishing the ends of rod 96 more light enters rod 96 from source 86 and more light reflects back into rod 96 at surface 100.
A semi-tubular, i.e., C-shaped in cross section, housing 104 surrounds rod 96 and includes an opening 106 along its length. The opening 106 defines upper and lower edges of display elements 80a-80i and includes formations, described hereafter, for retention of gel strips 24 adjacent the rod 96. Light escaping rod 96 by way of opening 106 passes through the gel strips 24 to provide the desired color indicia.
With reference to FIG. 6 in conjunction with FIG. 5, the housing 104 comprises an inner semi-tubular element 108 and an outer semi-tubular element 110, both concentric to rod 96. The outer semi-tubular element 110 includes an opening along its length defining the opening 106. The inner semi-tubular element 108 includes an opening similar to that of the element 110 but occupying a larger angular portion, as viewed in cross section, of the element 108. Upper and lower gel strip retention spaces 112 are formed in the region between outer semi-tubular element 110 and rod 96 but unobstructed by inner semi-tubular element 108. As shown in FIG. 6, a gel strip 24 lies along the surface portion of rod 96 exposed by opening 106, its upper and lower edges positioned within upper and lower retention spaces 112, respectively. A transparent cover sheet 114 lies on top of gel strips 24 with its upper and lower edges also held within upper and lower retention spaces 112, respectively. The cover sheet 114 includes light impervious bars 116 (FIG. 5) defining borders between individual display elements 80a-80i.
To mount gel strips 24 within the respective display elements 80a-80i, the lower edge of cover sheet -14 is placed in the lower retention space 112. Selected gel strips 24 are then aligned with respect to bars 116 behind the cover sheet 114 with their lower edges inserted in the lower retention space 112 between the sheet 114 and rod 96. When the selected gel strips 24 are suitably aligned with respect to the bars 116 of sheet 114, the upper edges of the gel strips 24 and the cover sheet 114 are inserted within the upper retention space 112. Gel strips 24 are then held against the rod 96. When light is injected into rod 96 from light source 86, the light escapes rod 96 by way of opening 106. Gel strips 24 filter the escaping light and provide the desired color indicia.
A mounting strip 120 attaches to the bottom of housing 104 and provides a stable base for placing display 80 upon console 81. Mounting strip 120 may include fastening means, e.g., a magnetic element or adhesive, for attachment to console 81. Display 80 is placed adjacent the faders 16 with each display element 80a-80h positioned adjacent a corresponding fader 16a-16i. An operator of console 81 adjusts the output of light source 86 by adjusting knob 90 and views display 80 to determine the color of stage lights 14 associated with each fader 16. Shield 82 may be provided with an opening 122 permitting escape of some light from source 86 onto the controls of console 81 to aid in manipulation of faders 16. Also, additional light may be provided on the console 81 by, for example, a display panel 80j having no gel strip 24 mounted therein.
Thus a display for a lighting control console has been shown and described. The display provides color indica for quickly associating a lighting control console fader with a colored stage light. An operator is able to determine immediately the color of the corresponding stage light without resorting to use of crowded written notation on adhesive tape placed next to the faders. The display provides and attractive addition to lighting control consoles with its multi-colored display elements. Each display element may be adapted to use the same filter material as is used on the corresponding stage light. A precise representation of the light available from that stage light is provided to the operator of the control console.
While a preferred embodiment of the present invention has been shown and described, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the invention in its broader aspects. For example, the subject of the present invention is applicable to lighting control consoles having any number of faders, indeed the larger the number of faders the greater the benefit provided by the present invention. Also, while the present invention has been illustrated using a light source to pass light through a filter element, the present invention can be practiced without the light source by using a variety of colored display elements. The invention has been shown with displays positioned adjacent the faders, but the scope of the invention includes other display arrangements, such as placing colored displays on the fader rather than adjacent the fader. Furthermore, the second illustrated embodiment of the present invention is shown with a single light source, but multiple light sources and a control circuit similar to the circuit of FIG. 3 can be used in such embodiment. The appended claims are therefore intended to cover all such changes and modifications as fall within the true spirit and scope of the invention.
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A display for a stage lighting control console provides colored display elements adjacent light control devices of the console. Each colored display element corresponds in color to the color of a stage light associated with the adjacent light control device. The colored display elements are replaceable or remountable whereby the display accommodates different stage lighting configurations by rearrangement or substitution of the colored display elements.
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BACKGROUND
1. Field
The invention relates to the field of electrical signals and more particularly, to the reflection of electrical signals along a circuit path.
2. Background Information
Electrical circuits often have their operation driven by a signal which is known as a “clock” signal (which may also be called a “trigger” signal). The trigger signal typically takes the form of a pulse which rises from a first predetermined voltage level (typically called “low”) to a second predetermined voltage level (typically called “high”). Of course, the designation of which voltage level constitutes a “low” or “high” is merely a matter of convention. Circuits which receive a trigger signal typically have their operation triggered when the trigger signal crosses a “trigger” level. The trigger level is a voltage level between the first predetermined level and the second predetermined level. As the voltage of the trigger signal rises between these levels, it crosses the trigger level with the result that the circuit receiving the trigger signal may perform an operation. For example, the well known latching circuit may read in and store a signal on a data input terminal where the trigger signal crosses the trigger level. When this occurs, the latch circuit is said to have been “triggered” or “clocked”. Of course, a circuit's operation may also be triggered by the transition of the trigger signal from the higher predetermined voltage level to the lower predetermined voltage level. The transition of a trigger signal from low to high voltage levels may be referred to as a “rising” edge of a trigger signal. Likewise, the transition from high to low voltage levels of a trigger signal may be referred to as the “falling” edge.
Some circuits are capable of performing multiple operations, with some operations triggered on a rising edge and others triggered on the falling edge of a trigger signal. For example, a memory circuit may write (e.g. store) signals on its data input terminals and may read (e.g. output) signals stored in the memory to its data output terminals. The memory write operation may be triggered on the rising edge of a trigger signal and the memory read operation may be triggered on the falling edge of the trigger signal. Some memory circuits may be capable of performing a write operation and a read operation each triggered by the rising and falling edges of the same trigger signal.
In some situations it may be desirable to substantially delay the triggering of the operation on the rising edge, without causing substantial delay to the triggering of the operation on the falling edge, or vice versa. For example, it may be desirable to delay the triggering of a memory write operation on the rising edge of a clock pulse, without delaying the triggering of a memory read operation on the falling edge of the same trigger signal. This may be desirable when the signals on the data input terminals are not available at the point in time when the rising edge of the trigger signal triggers a memory write operation. The circuits which read data signals from the data output terminals of the memory may be configured to receive the data signals shortly after the same trigger signal triggers a memory read operation. Thus it may not be acceptable to simply delay the entire trigger signal to delay the rising edge, because by delaying the entire trigger signal, both the rising and falling edges are delayed, which interferes with the memory read operation. The circuit reading data signals from the memory would be forced to incur delays to accommodate the delays in the memory write operation.
One solution to this problem is to narrow the trigger signal so that the falling edge occurs sooner after the rising edge. By narrowing the trigger signal, the time at which the rising edge occurs may be delayed without altering the time in which the falling edge occurs. This approach may not be feasible in applications where the trigger signal is distributed to multiple circuits, some of which are adapted to expect the rising edge to occur at a predetermined point in time and at least one circuit adapted to expect the rising edge to be delayed. In this situation, simply adapting the trigger signal generator to produce a narrower trigger signal may be undesirable because the operation of some of the circuits receiving the trigger signal may be adversely affected. Those skilled in the art will recognize that the same situation could arise in situations where the timing of the rising edge is to be left unchanged, but where the falling edge needs to occur sooner in time.
Thus, there exists a continuing need for a mechanism by which the timing of one edge of a signal received by circuit may be adjusted without substantially changing the timing of the other edge of the signal, and without altering the timing of the signal edges to other circuits which receive the signal.
SUMMARY
An apparatus includes a circuit and a signal source to supply a trigger signal to the circuit. The signal source is adapted to supply the trigger signal such that a reflection of the trigger signal delays the time at which the circuit is triggered.
BRIEF DESCRIPTION OF THE DRAWINGS
The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, may be further understood by reference to the following detailed description read with reference to the accompanying drawings.
FIG. 1 shows a system in accordance with one embodiment of the present invention.
FIG. 2 shows an embodiment of stud path in accordance with the present invention.
FIG. 3 illustrates an embodiment of an incident trigger signal in accordance with the present invention.
FIG. 4 is an illustration showing the trigger signal embodiment of FIG. 3 as it travels over a distance D.
FIG. 5 shows an embodiment of a composite signal produced in accordance with the present invention.
DETAILED DESCRIPTION
In one embodiment of the present invention an incident trigger signal and a reflected trigger signal are superimposed to form a composite trigger signal. Relative to the incident trigger signal, the rising edge of the composite trigger signal is delayed without creating substantial delay in the falling edge of the composite trigger signal. The following description and drawings describe the present invention in terms of specific embodiments and examples, however, the scope of the present invention is defined only by the amended claims.
FIG. 1 shows a system in accordance with one embodiment 100 of the present invention. The system comprises a processor 118 , a memory controller 102 , and a memory 104 . The processor 118 and memory controller 102 are coupled by way of processor bus 120 . Memory controller 102 and memory 104 are coupled by way of memory bus 110 . Processor 118 may write data to memory by placing data signals on processor bus 120 . Memory controller 102 may transfer these data signals to memory bus 110 , from which they may be received into memory 104 , e.g. written to memory 104 . Processor 118 may read data signals from memory 104 by indicating to memory controller 102 an address in the memory 104 from which to read data signals. Memory controller 102 may signal memory 104 to place data signals from this address on memory bus 110 . Memory controller 102 may transfer the data signals from memory bus 110 to processor bus 120 .
Embodiment 100 further comprises trigger signal generator 106 to generate synchronized trigger signals to memory controller 102 and memory 104 . Trigger signals serve to synchronize the operation of memory controller 102 and memory 104 . This is commonly referred to as a common clock circuit configuration. Trigger signals propagate from signal generator 106 to memory controller 102 over signal path 114 . Trigger signals propagate from signal generator 106 to memory 104 over signal path 116 . The trigger signal generated by signal generator 106 is referred to as the incident trigger signal. In accordance with one embodiment of the present invention, a junction 112 is formed on signal path 116 and signal path 108 is joined thereto. Signal path 108 will henceforth be referred to as stub path.
FIG. 2 shows an embodiment 200 of stub path 108 in accordance with the present invention. In this embodiment junction 112 is a simple “T” connection of stub path 108 and signal path 116 . Stub path is unterminated. That is, no resistive, capacitive, inductive, or other electrical load is coupled between stud path 108 and an electrical ground. Stub path 108 floats electrically and may be a strip of conductive material of length D′ which is unterminated. Length D′ may be chosen to be approximately the same as the length D of signal path 116 as is present between junction 112 and memory 104 . Stub path length D′ may not be exactly equal to the length D, and may in fact fall within some percentage of length D. For example, length D′ may “of an order” of the length D. In some embodiments, stub path length D′ may vary between approximately 5% and 50% of the length of signal path 116 between junction 112 and memory 104 . Determination of stub length D is described further below.
FIG. 3 illustrates an embodiment 300 of an incident trigger signal in accordance with the present invention. Trigger signal 300 is illustrated in accordance with metal oxide semi-conductor technology (CMOS), which comprises a well known predetermined low voltage level of Vss and a predetermined high voltage level of Vdd (source and drain voltages respectively for CMOS transistors). Of course, other semiconductor technologies are equally applicable to the present invention. Trigger signal 300 is illustrated in terms of its voltage level over time. Trigger signal 300 comprises a rising edge 302 , a plateau 306 , and a falling edge 304 . Clock pulse 300 takes a certain period of time Tr to rise from low voltage Level Vss to the high voltage level Vdd. This period of time may be referred to as the rise time of the leading edge 302 of trigger signal 300 .
FIG. 4 is an illustration showing the trigger signal embodiment of FIG. 3 as it travels over a distance D. Two distinct points in time are illustrated. At a first time t, the trigger signal 300 begins to rise from the low voltage Vss. At a later time t+Tr, the trigger signal 300 has reached plateau level 306 . During the time it took trigger signal 300 to rise from the low voltage level to the high voltage level, e.g. the rise time Tr, the trigger signal may propagate a distance D down signal path 116 . For example, a trigger signal with a 1 ns (one nanosecond) rise time may propagate approximately five inches down the signal path 116 during the rise time. This distance may be calculated by multiplying 1 ns by the speed of electrical signal propagation, which may vary according to the electrical properties of signal path 116 but which may, in some embodiments, approximate the well-known value of the speed of light. As previously described, the length D′ of stub path 108 need only be “of an order” or D and not precisely equal to D.
FIG. 5 shows an embodiment of a composite signal produced in accordance with the present invention. Stub path 108 may reflect an incident trigger signal 508 to produce a reflection signal 510 on signal path 116 . The length of stub path 108 is appropriately chosen as described previously. The rising and falling edges of reflection signal 510 may be offset from the rising and falling edges of the incident signal 508 . Incident signal 508 and reflected signal 510 may superimpose over time to form a composite trigger signal 506 . Composite signal 506 may have several advantageous properties. A plateau 502 may be formed in the rising edge of composite signal 510 . Plateau 502 serves to delay the attainment of voltage levels above the plateau level 502 . A plateau 504 may also be formed on falling edge of composite signal 506 , however, plateau 504 of falling edge may occur at a voltage level substantially below plateau 502 of the rising edge. A circuit whose operation is driven by composite trigger signal 506 is adapted to be triggered at a voltage level above plateau level 502 . Triggering of the circuit's operation may thus be delayed, due to the rising edge delay in reaching voltage levels above the plateau level 502 .
For example, consider a memory circuit with a memory write operation triggered by the rising edge of incident signal 508 at a trigger level of 0.5 volts. According to the signal timings illustrated in FIG. 5, said circuit may be triggered for write operation at approximately 1 ns and 11 ns. Now consider a memory circuit with a write operation triggered at a 1.1V trigger level by composite signal 506 . The write operation of such a circuit will be triggered at approximately 2.5 ns and 12.5 ns.
Now consider a memory circuit with a memory read operation triggered by the falling edge of incident signal 508 at a trigger level of 0.5 volts. According to the signal timings illustrated in FIG. 5, said circuit may be triggered for read operation at approximately 6 ns and 16 ns. Now consider a memory circuit adapted to trigger a read operation at trigger level of 1.1V by falling edge of composite signal 506 . The read operation of such a circuit will again be triggered at approximately 6 ns and 16 ns. In other words, the read operation of the two memory circuits is triggered at approximately the same time. In other words, by applying composite trigger signal 506 to a circuit with appropriately adapted trigger levels, the trigger time of an operation on the rising edge of composite trigger signal 506 may be substantially delayed without affecting the trigger time of an operation triggered on the falling edge of composite trigger signal 506 .
The invention is in no way limited to the use of stub paths to produce the composite signal 506 . Any mechanism for producing a trigger signal with the properties of composite signal 506 may also be employed. One embodiment employs a stub path 108 to produce a reflection signal 510 to combine with an incident signal 508 produced by a signal generator 106 . However, other embodiments could produce a signal with properties similar to those of composite signal 506 using an arrangement of transistors or other circuit components. Such embodiments could potentially employ reflection signals, but would not necessarily do so. From the perspective of the circuit being triggered by the composite signal 506 , the source (e.g. the specific circuit arrangements and adaptations) which produce composite signal 506 is less important than the properties of composite signal 506 itself. Thus, the invention is not limited to a particular circuit arrangement acting as the source of the composite signal 506 .
Returning to FIG. 1, a memory write operation triggered on the rising edge of a trigger signal could be substantially delayed by applying the present invention to signal path 116 and memory 104 . This may provide memory controller 102 with substantial additional time to establish data signals on memory bus 110 before the write operation is triggered. Trigger signals on other signal paths, for example path 114 , would not be affected. Furthermore, memory read operations triggered by the falling edge of the trigger signal would not be substantially delayed as a result of delaying the memory write operations. This may be advantageous in applications where more time is needed to set up the data on memory bus 110 for a write operation, without affecting the performance of a read operations, and without affecting the timing of trigger signals to other circuits supplied by signal generator 106 .
Those skilled in the art will of course recognize that the present invention may also be applied to delay circuit operations triggered on the falling edge of a signal. In such a case, the trigger level of the circuit for both rising and falling edge operations would be adjusted below the level of the plateau on the falling edge of composite signal 506 . Thus, operations triggered on the rising edge would not be substantially delayed, because they are triggered at levels less than the level of the rising edge plateau. Operations triggered on the falling edge might be substantially delayed because they are triggered at levels less than the level of the falling edge plateau.
While the invention has been described in terms of specific embodiments and examples, those skilled in the art will appreciate numerous modifications are possible which fall within the scope of the invention. The specific examples and embodiments described herein are presented for purposes of illustration only, and the scope of the present invention should be construed only in light of the claims which follow.
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An apparatus includes a circuit and a signal source to supply a trigger signal to the circuit. The signal source is adapted to supply the trigger signal such that a reflection of the trigger signal delays the time at which the circuit is triggered.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an overvoltage protection system for diverting transient overvoltages with two electrodes, each of which has one current terminal, an air-breakdown spark gap which acts between the electrodes, and a housing which holds the electrodes.
2. Description of Related Art
Electrical, but especially electronic measurement, control and switching circuits, mainly also telecommunications means and systems, are sensitive to transient overvoltages, as can occur especially as a result of atmospheric discharges, i.e., by lightning stroke currents, but also due to short circuits and switching operations in power supply networks. This sensitivity has increased to the degree to which electronic components, especially transistors and thyristors, are used; mainly, the integrated circuits which have been increasingly used are greatly endangered by transient overvoltages.
In addition to the overvoltage protection element underlying the invention (see, German Patent No. DE 37 16 997 C2), i.e., one with an air-breakdown spark gap, there are overvoltage protection elements with an air-sparkover spark gap in which a creeping discharge occurs upon triggering (compare, published German Patent Applications DE 27 18 188 A1, DE 29 34 236 A and DE 31 01 354 A1).
Overvoltage protection elements of the type underlying the invention, i.e, those with an air-breakdown spark gap, compared to overvoltage protection elements with an air-sparkover spark gap, have the advantage of higher surge current carrying capacity, but the disadvantage of a higher and also not especially constant operating voltage.
Various overvoltage protection elements with an air-breakdown spark gap have been developed which have also been improved with respect to the operating voltage (compare DE 41 41 681 A1, DE 41 41 682 A1, DE 42 44 051 A1 and DE 44 02 615 A1, the last mentioned German Patent corresponding to U.S. Pat. No. 5,604,400).
The overvoltage protection element known from U.S. Pat. No. 5,604,400 has already acquired great importance in practice, is produced and sold by the assignee of the present application under the name FLASHTRAP FLT (see, '98/99 catalog of the company Phoenix Contact GmbH & Co, Blomberg, Germany, Parts Catalog 7 “TRABTECH Overvoltage protection” and the explanations given there on the problem of overvoltages, especially on pages 3-5 and 12-17). In this known overvoltage protection element, each electrode has a terminal leg and an arcing horn which runs at an acute angle to the terminal leg, and the arcing horns of the two spaced electrodes together form the air-breakdown spark gap. Here, between the opposite ends of the terminal legs of the two electrodes, there is an ignition aid which triggers a creeping discharge. In addition, it can be obtained from U.S. Pat. No. 5,604,400 that it is advantageous if the arcing horns of the electrodes are provided with a hole in their areas which border the terminal leg.
The above addressed overvoltage protection element, which is known from U.S. Pat. No. 5,604,400, is made in a practical implementation such that, on the one hand, it has a surge current carrying capacity of 100 kA, and on the other hand, it is suitable for extinguishing network follow currents into the range of 100 A.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide another overvoltage protection element with an air-breakdown spark gap which, with reference to the operating voltage, the lightning surge current and the network follow current carrying capacity behavior and the network follow current extinguishing behavior meets current requirements in a special way.
The overvoltage protection element as in accordance with the present invention is, first of all, essentially characterized in that the electrodes are located parallel to one another. In this case, the electrodes can be made cylindrical and can have a circular, oval and/or a rectangular cross section. It is especially advantageous if the electrodes have different cross sections over their length. Different cross sections means not only a difference in geometry, therefore circular, oval or rectangular, but also in dimensions; therefore, the electrodes can be staggered (stepped) in cross section along their length, so that the area which is to act as the air-breakdown spark gap can be locally set in a special way.
It is especially advantageous for the serviceability of the overvoltage protection element in accordance with the present invention if the interior of the housing which holds the electrodes is lined, the lining being made, preferably, of POM Teflon®.
In the prior art, especially also in the overvoltage protection element which is disclosed by U.S. Pat. No. 5,604,400, in cross section, the air-breakdown spark gaps are generally designed as extinguishing spark gaps. Conversely, another teaching of the invention which acquires special importance is that, in the overvoltage protection element in accordance with the invention, the housing which holds the electrodes is closed and pressure resistant.
In particular, there are different possibilities for embodying and developing the overvoltage protection elements of the invention. Nonetheless, these and further objects, features and advantages of the present invention are described below in connection with the accompanying drawings which, for purposes of illustration only, show only some of the possible embodiments in accordance with the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal section through an especially preferred embodiment of an overvoltage protection element in accordance with the invention;
FIG. 2 is an exploded view of the overvoltage protection of FIG. 1;
FIG. 3 shows the overvoltage protection element of FIGS. 1 and 2 with the housing opened;
FIGS. 3A-3C are cross-sectional views taken along lines A—A, B—B and C—C in FIG. 3; and
FIG. 4 is a view corresponding to FIG. 3, but of a modified embodiment.
DETAILED DESCRIPTION OF THE INVENTION
The overvoltage protection element as claimed in the invention shown in the figures is used to divert transient overvoltages and to limit surge currents, especially lightning surge currents, and to extinguish network follow currents; lightning surge currents up to 100 kA can be diverted and network follow currents of typically 3 to 4 kA, a maximum of 25 kA or even of 50 kA, can be extinguished.
The overvoltage protection element in accordance with the invention comprises, in its essential structure, two electrodes 3 , 4 , each of which has a current terminal 1 , 2 , respectively, an air-breakdown spark gap 5 which acts between the electrodes 3 , 4 , and a housing 6 which holds the electrodes 3 , 4 .
As the figures show, the electrodes 3 , 4 are located next to one another with their longitudinal axes parallel to one another. In the illustrated embodiment, the electrodes 3 , 4 are cylindrical with a circular cross section (FIG. 3 A). However, other shapes may be used. For example, the electrodes can an oval and/or a rectangular cross section (FIGS. 3 B & 3 C). Furthermore, as shown at each end of the electrodes, they can be rounded or beveled in the area of their edges.
As FIGS. 1 & 3 show, the electrodes 3 , 4 have different cross sections along their length. The electrodes 3 , 4 , therefore, have electrode sections 3 a, 3 b, 3 c, 3 d, and 3 e and 4 a, 4 b, 4 c, 4 d, and 4 e. The electrode sections 3 c and 4 c have the largest diameter. Between the electrodes 3 c and 4 c there is, therefore, the smallest distance so that the air-breakdown spark gap 5 is formed between the electrode sections 3 c and 4 c.
In this embodiment, the current terminals 1 and 2 of two electrodes 3 and 4 lie on opposite sides. As can be easily seen from the FIGS. 1-3, the terminals 1 and 2 run parallel to one another. However, embodiments are also possible in which the current terminals of the two electrodes run towards one another at an acute angle. Likewise, an overvoltage protection element according to the invention can be provided where the current terminals of the two electrodes lie on the same side as shown in FIG. 4 .
For the serviceability of the overvoltage protection element in accordance with the invention, it is especially advantageous when, as the figures do not show, the interior of the housing 6 which holds the electrodes 3 , 4 is lined, the lining being formed preferably of POM Teflon®, i.e., polytetrafluoroethylene.
The embodiment of an overvoltage protection element in accordance with the invention which is shown in the figures is an especially advantageous one, in that the housing 6 which holds the electrodes 3 , 4 is closed and pressure resistant. In particular, the housing 6 which holds the electrodes 3 , 4 is made of a cylindrical housing jacket 7 and two housing flanges 8 , 9 , one of which is provided on each end of the housing jacket 7 .
In this embodiment, in the above described structure of the housing 6 which holds the electrodes 3 , 4 , the compressive strength of the housing 6 is achieved in conjunction with an outer pressure cylinder 10 . In particular, the pressure cylinder 10 has a pressure sleeve 11 , the pressure sleeve 11 being provided, on one end, with an outer thread 12 , and on the other side, with a flange 13 which projects inwardly, a union nut 14 being screwed onto the pressure sleeve 11 .
The production of the overvoltage protection element according to the invention, i.e. the production of individual parts and the assembly of these individual parts, is exceptionally simple and thus economical. The current terminals 1 , 2 , the electrodes 3 , 4 , the individual parts of the housing 6 , specifically the housing jacket 7 and the housing flanges 8 , 9 , and the individual parts of the outer pressure cylinder 10 , i.e., the pressure sleeve 11 and the union nut 14 , are rotationally symmetrical parts which are either easily available or can be series produced as rotary parts on modem machine tools.
As especially FIG. 1 shows, each housing flange 8 , 9 is provided both with a through hole 15 , 16 and also with a blind hole 17 , 18 . The housing flanges 8 , 9 made in this way, therefore, allow both passage of the current terminals 1 , 2 , and also on the respective other side, end-side bearing of the electrodes 3 , 4 , specifically in the area of the electrode sections 3 e, 4 e.
It applies to the described, especially advantageous embodiment of an overvoltage protection element of the invention that the housing flange 8 , 9 can be braced to seal against the cylindrical housing jacket 7 , using the outer pressure cylinder 10 , specifically by the fact that the union nut 14 is screwed onto the pressure sleeve 11 .
In the overvoltage protection element according to the invention, the housing 6 which holds the electrodes 3 , 4 uses air as the extinguishing gas; but, it can also be provided with another known extinguishing gas, for example, SF 6 . The extinguishing gas can be under atmospheric pressure in the housing 6 which holds the electrodes 3 , 4 , but it is also possible, in the described embodiment, in which the housing 6 which holds the electrodes 3 , 4 is made pressure resistant and pressure proof, that the extinguishing gas is under a pressure which differs from atmospheric pressure.
While various embodiments in accordance with the present invention have been shown and described, it is understood that the invention is not limited thereto, and is susceptible to numerous changes and modifications as known to those skilled in the art. Therefore, this invention is not limited to the details shown and described herein, and includes all such changes and modifications as are encompassed by the scope of the appended claims.
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An overvoltage protection element for diverting transient overvoltages, with two electrodes ( 3, 4 ), each of which has a current terminal ( 1, 2 ), an air-breakdown spark gap ( 5 ) between the electrodes ( 3, 4 ) and a housing ( 6 ) which holds the electrodes ( 3, 4 ). The overvoltage protection element with an air-breakdown spark gap ( 5 ), with reference to the operating voltage, the lightning surge current and network follow current carrying capacity behavior and the network follow current extinguishing behavior meets current requirements in a special way by the electrodes ( 3, 4 ) being located parallel to one another.
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The present Application claims priority from Korean Application No. 10-2002-0055101 filed Sep. 11, 2002, which is incorporated herein in full by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a high dimensional similarity join method, and more particularly, to a partition-based high dimensional similarity join method for allowing similarity to be efficiently measured by beforehand dynamically selecting space partitioning dimensions and the number of the partitioning dimensions using a dimension selection algorithm.
2. Description of the Prior Art
In general, multimedia data such as audio, video, images and text, time-series data indicating a sequence over a period of time, and a large amount of business data used for various data warehouses first go through preprocessing procedures and are then mapped to points on a high dimensional space for search, management and the like, as shown in FIG. 6 . The similarity between the mapped data is measured based on the Euclidean distance between data in the high dimensional space. For example, the similarity between two image files is measured based on the distance between two points mapped onto the high dimensional space.
The term ‘similarity join’ is defined as a method of efficiently retrieving similar data among data sets when high dimensional data are provided as input data from huge multimedia databases, medical databases, scientific databases, time-series databases and the like, and the similarity join is indispensably required in high dimensional data systems such as image and multimedia data systems, time-series data systems and the like.
The similarity join can be modeled as follows.
Assuming that data sets R and S exist in a d-dimensional space and arbitrary elements r and s for the data sets R and S are represented as r=[r 1 , r 2 , . . . r d ], s=[S 1 , S 2 , . . . S d ], respectively, a similarity join query can be formulated as follows:
R × S = { ( r , s ) ❘ ( ∑ i = 1 d r i - s i p ) 1 / p ≤ ɛ , r ∈ R , s ∈ S } ( 1 )
where p is a special distance metric, ε is a cutoff similarity value as a user-defined parameter, and only data pairs of which the spatial distances are smaller than ε among data pairs consisting of the elements of the data sets R and S are returned as results.
Conventional similarity join methods are well applied to low dimensional data but are very inefficient for the high dimensional data requiring very large dimensions, i.e. 10 or 100, even 1000 dimensions, in view of performance time and system storage requirements.
Typical examples of conventional similarity join methods may include a similarity join method based on the ε-kdB trees (“High dimensional similarity joins” by K. Shim, R. Srikant and R. Agrawal, Proceedings of the 1997 IEEE International Conference on Data Engineering, 1997) and a similarity join method using the ε-grid order (“ε-grid order: An algorithm for the similarity join on massive high dimensional data” by C. Böhm, B. Braunmuller, F. Krebs, and H. -P. Kriegel, Proceedings of the 2001 ACM-SIGMOD Conference, 2001).
In the similarity join method based on the ε-kdB trees, a data space is divided into cells having an area of ε along one dimension axis and data are stored in the cells, and the ε-kdB trees having multi-dimensional index structures are constructed with respect to respective cells. This method can efficiently reduce the number of joins by limiting the partitioning area for the data division in ε unit. However, since the ε-kdB tree structures indicating the respective partitions must be held in the system storage, the required system storage is also increased as space dimensions are increased. As a result, the time required for performing the similarity joins also increases proportionally.
In addition, in the algorithm of performing the similarity join using the ε-grid order, the similarity join for the high dimensional data is performed based on special ordering of the data which is obtained by laying grids having a cell length of ε over the data space and then comparing the grid cells in lexicographical order. This algorithm can provide efficient scaling of very massive data sets even with limited storage contrary to the method using ε-kdB trees. However, there is a disadvantage in that since all points between p −[ε.ε. .ε] and p +[ε.ε. .ε] must be considered in order to search join pairs of p, as shown in FIG. 7 , the number of searched grid cells in an interval gets very large as dimensions increase, resulting in an increased performance time.
Meanwhile, although space partitioning methods used in low dimensional space data systems may be applicable to similarity joins in a high dimensional data space, it is not desirable from a practical point of view in that they require space partitioning for all the dimension axes. In other words, since the number of cells that result from partitioning explodes as the number of dimension axes participating in the partitioning increases (for example, if each dimension axis is divided into 10 continuous sub-intervals, the numbers of cells generated for 8, 16, 32 and 64 dimensions are 10 8 , 10 16 , 10 32 , and 10 64 , respectively), it is likely that these numbers are usually larger than the number of points in the original data sets before being partitioned. If the number of cells that result from partitioning gets larger, a data skew phenomenon is excessively generated. Thus, the algorithm itself based on space partitioning becomes inefficient. Herein, the data skew phenomenon means that when high dimensional spaces are divided into cells, the data distribution in the cells is not uniform, as shown in FIG. 8 .
Therefore, there is a need for a new similarity join method in which similarity joins for high dimensional data can be efficiently performed within a short period of performance time and massive storage space is not required during performance of the similarity joins.
SUMMARY OF THE INVENTION
A primary object of the present invention is to provide a method of efficiently performing similarity joins for high dimensional data during a relatively short period of time without requiring massive storage space.
Another object of the present invention is to provide a partitioning dimension selection algorithm capable of improving the performance of similarity joins. The partitioning dimension selection algorithm is to select dimensions and the number of the dimensions, which can dynamically and efficiently partition a data space by using distribution values for respective axes of given data sets.
The present invention provides a partition-based high dimensional similarity join method comprising the steps of partitioning a high dimensional data space and performing joins between predetermined data sets. Dimensions for use in partitioning the high dimensional data space and the number of partitioning dimensions are determined in advance before the space partitioning, and the joins are performed when respective cells of the data sets overlap with each other or neighboring each other.
Preferably, the method further comprises the step of counting the number of join computations which can occur in the joins between the respective cells of the data sets.
The dimensions for use in partitioning the high dimensional data space may be determined based on the number of join computations.
Preferably, the number of dimensions for use in partitioning the high dimensional data space d p is obtained by comparing the size of the data sets and the size of disk blocks in which the data sets are stored, and can be obtained by the following equation:
d
p
=
log
Min
(
R
block
,
S
block
)
BlockSize
log
⌈
1
/
ɛ
⌉
,
where |R| block and |S| block are the total numbers of disk blocks in which the data sets R and S are stored, respectively, the BlockSize is the size of the disk blocks, and [1/ε] is the number of the cells.
The number of join computations may be obtained by computing the number of entries of the data sets R and S included in the respective cells for respective dimensions and then counting the number of distance computations of joins between the cells for the respective dimensions.
Alternatively, the number of join computations may be obtained by computing the number of entries of the data sets R and S included in sampled cells among the cells for the respective dimensions and then counting the number of distance computations of joins between the cells for the respective dimensions.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present invention will become apparent from the following description of a preferred embodiment given in conjunction with the accompanying drawings, in which:
FIG. 1 is a diagram showing a configuration of an example of hardware to which the present invention is applied;
FIG. 2 is a flowchart illustrating a partition-based high dimensional similarity join method according to the present invention;
FIG. 3 shows a partitioned data space after a partition step for two dimensions;
FIGS. 4 a and 4 b are diagrams explaining a concept of counting the number of distance computations expected for specific data sets R and S;
FIG. 5 shows a partitioning dimension selection algorithm for the data sets R and S;
FIG. 6 shows a concept that high dimensional data go through preprocessing procedures and are then mapped to points on a high dimensional space for search, management and the like;
FIG. 7 shows a data space in similarity joins using the conventional ε-grid order; and
FIG. 8 shows that data distribution in cells is not uniform when the high dimensional space is divided into the cells.
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a preferred embodiment will be described in detail with reference to the accompanying drawings to provide a non-limiting illustrative description of the present invention. However, the embodiments are merely examples of the present invention, and thus, the specific features described below are merely used to more easily describe such embodiments and to provide an overall understanding of the present invention. Accordingly, one skilled in the art will readily recognize that the present invention is not limited to the specific embodiments described below. Furthermore, the descriptions of various configurations and components of the present invention that are known to one skilled in the art are omitted for the sake of clarity and brevity.
Also, the present invention is not required to overcome the disadvantages described above and the other disadvantages, and an illustrative, non-limiting embodiment of the present invention may not overcome any of the disadvantages.
FIG. 1 is a diagram showing a configuration of an example of hardware to which the present invention is applied.
As shown in FIG. 1 , single or multiple processors P 1 , P 2 , . . . Pn 11 , a memory region 12 in a main memory device, and an input/output processor 15 are connected via a system bus 16 . A shared memory area 13 exists in the memory region 12 of the main memory device, and the input/output processor 15 is connected with a disk 14 as an auxiliary memory device. The present invention can operate under general hardware circumstances including the single or multiple processors and the shared memory area.
A partition-based high dimensional similarity join method according to the present invention will be described below with reference to FIG. 2 .
The partition-based high dimensional similarity join method according to and embodiment of the present invention comprises the steps of partitioning a high dimensional data space (S 100 ), determining the number of dimensions for use in partitioning the high dimensional data space before the space partitioning (S 200 to S 220 ), determining the dimensions for use in partitioning the high dimensional data space (S 300 to S 320 ), and performing joins between predetermined data sets (S 400 ).
Each step will be specifically described below.
In partition step S 100 , the entire data space is partitioned into cells of a length of ε indicating a cut-off similarity value. Assuming all entries in the data space are within a unit hypercube, i.e. when each dimension axis ranges between [0,1], each dimension is partitioned into [1/ε] cells. Each entry in the data sets R and S, which participate in the similarity join, is assigned and stored in a relevant cell to which it belongs through preprocessing procedures of the data. FIG. 3 shows the partitioned data space after the partition step for two dimensions, wherein small rectangles represent the resulting cells.
In similarity join step S 400 , data pairs satisfying a special similarity request are searched from two data sets that participate in the similarity join. However, each cell from one of the data sets does not need to be paired with every cell of the other data set, but is paired only with cells which it overlaps or neighbors in the data space. Generally, in a d-dimensional data space, a cell in a data set that is not located at a border of the unit hypercube should be paired with 3 d cells in the other set. For example, in the two-dimensional data space shown in FIG. 3 , a cell P shall be paired with the 9 shaded cells among cells of the other set for the purpose of the similarity join.
As described above, in case of the high dimensional similarity join, if a data space is divided by employing all the dimensions during the partition step, the number of cells resulting from the partitioning may explode so that the data skew phenomenon can be serious. This consequently causes an increase of disk I/O cost. In addition, if the number of partitioning dimensions increases, the computing cost of hash functions for mapping the data to relevant cells also acts as another source of overhead. Therefore, instead of partitioning the data space by employing all the dimensions, it is desirable to perform the partition of the data space by selecting only several dimensions that have ‘uniform distribution’ of the data among the dimensions. Herein, the meaning of ‘uniform distribution’ is understood as a relative concept, i.e. one dimension shows uniform distribution for one data set but does not show uniform distribution for another data set. In addition, as the cut-off similarity value varies, the degree of uniformity of the dimension changes accordingly. That is, the degree of uniformity of the dimension is determined dynamically based on the given two data sets and the cut-off similarity value.
Therefore, the present embodiment does not partition the data space by employing all the dimensions but performs the space partitioning by selecting several dimensions showing ‘uniform distribution’ of the data from all the dimensions.
Hereinafter, the steps of determining the number of dimensions for use in partitioning the high dimensional data space before the space partitioning (S 200 to S 220 ) and determining the dimensions for use in partitioning the high dimensional data space (S 300 to S 320 ) according to a preferred embodiment of the invention will be described.
The Number of Partitioning Dimensions
In case of processing a similarity join for the two data sets R and S in the high dimensional space, under the assumption that data points are uniformly distributed in the data space, when the number of partitioning dimensions is d p , the CPU cost [Cost(CPU)], which is computed by counting the number of pairing of data entries of the data sets R and S, can be formulated as follows:
Cost
(
CPU
)
=
R
×
S
×
(
3
⌈
1
/
ɛ
⌉
)
d
p
(
2
)
In addition, the disk I/O cost [Cost(IO)] as the disk access cost can be formulated as follows:
Cost( IO )=| R| block +3 dp |S| block, (3)
for the total number of disk blocks in which R and S are stored, |R| block for R and |S| block for S.
According to Equations (2) and (3), it is understood that as the number of partitioning dimensions d p increases, the CPU cost decreases (under an assumption that [1/ε]>3), while the disk I/O cost increases. That is, there is a trade-off between the CPU cost and the disk I/O cost in regard to the performance of the similarity join.
In this aspect, the method according to the present embodiment determines the number of partitioning dimensions by comparing the size of the data set with that of the disk block.
Assuming that the average cell size is the same as the size of a disk block, the total number of cells N p generated after the partition step can be computed as follows (S 200 ):
N p = Min ( R block , S block ) BlockSize ( 4 )
where |R| block and |S| block are the total numbers of disk blocks in which data sets R and S are stored, respectively, Min( ) is a function that returns a smaller of the values, and BlockSize is the size of the disk blocks.
Further, the number of cells N p ′ generated when the space is partitioned into the predetermined number of dimensions can be computed as follows (S 210 ):
N′ p =(┌1/ε┐) d p (5)
Therefore, from the equation, N p =N p ′. As a result, the number of partitioning dimensions d p can be obtained as follows (S 220 ):
d p = log Min ( R block , S block ) BlockSize log ⌈ 1 / ɛ ⌉ ( 6 )
Selection of Partitioning Dimensions
The size of the domain where data can exist in the high dimensional data space grows exponentially (phenomenon known as the ‘curse of dimensionality’), and accordingly, actual data existing in the high dimensional data space do not show a uniform distribution.
As described above, since the degree of uniformity of the dimension can be dynamically determined based on the two given data sets and the cut-off similarity value, the partitioning dimensions for the similarity join should be selected with consideration of the associated relationship among the plurality of data sets. As a result, data distribution of one data set is not a criterion of selection of the efficient partitioning dimension for the similarity join processing.
Considering the above aspects, as the criterion of selection of the efficient partitioning dimension for the similarity join processing, the present embodiment uses the number of pairings of the entries of the two data sets when the two data sets are joined to a relevant dimension axis, i.e. the number of distance computations, that is, the number of join computations which are generated in the case of joins between the resulting cells. The number of join computations is regarded as the join cost between cells for each dimension axis, and the partitioning dimension is selected based on the join cost beforehand computed for each dimension axis.
FIG. 4 a is a diagram explaining the concept of counting the number of distance computations expected for the specific data sets R and S.
Each entry in the data sets R and S is mapped to any one among [1/ε] cells of the length ε through space projection on one dimension axis in accordance with its coordinate value of the dimension axis. Then, for each dimension, the number of entries of the data sets R and S, which are included in each cell, is counted (S 300 ).
Thereafter, the number of distance computations that will occur in joins between the cells by using the number of entries is obtained (S 310 ). At this time, a cell in the data set R is paired joined with three cells in the data set S that are neighboring on or overlapping with it. That is, an arbitrary cell in the data set R is paired with the three cells in the data set S, i.e. a cell on the left side of it, one overlapping with it, and one on the right side of it.
For example, as shown in FIG. 4 b , if for a specific dimension, the data set R has 1, 3, 0, 5, . . . entries, respectively, and the data set S has 1, 3, 4, 2, 5, . . . entries, respectively, the number of distance computations is counted as follows:
{(1×1)+(1×3)}+{(3×1)+(3×3)+(3×4)}+{(0×3)+(0×4)+(0×2)}+{(5×4)+(5×2)+(5 ×5)}+ . . .
Finally, it is considered that the smaller the expected number of the distance computations obtained for each dimension axis is, the lower the join cost is, and finally the dimension having the lowest join cost is selected as the partitioning dimension (S 320 ).
Meanwhile, in the case of counting the number of distance computations, it is not necessary to actually partition and store the data, and the counting can be made by recording only the number of data belonging to each cell for the two data sets. That is, upon selection of the partitioning dimension, an actual join computation is not performed, and the number of distance computations required for the join is counted by using only the number of entries assigned to each cell.
In addition, in case of obtaining the number of entries, although the number of entries assigned to each cell for all the data sets may be obtained, it is also possible to obtain the number of entries by sampling a part of the data sets.
FIG. 5 shows a partitioning dimension selection algorithm for the data sets R and S, according to a preferred embodiment of the present invention.
Lines 7 to 11 and 12 to 16 in the algorithm are processes of computing the number of entries of the data sets R and S included in each cell for each dimension, and lines 18 to 24 are processes of counting the number of distance computations of joins between cells for each dimension.
As described above, the present embodiment of the invention allows the space partitioning algorithm, which has been generally used in the low dimensional space, to be applied to the high dimensional data space, so that even if the number of cells resulting from the space partitioning explodes, the similarity join can be performed while optimizing the CPU and I/O costs.
In addition, there is an advantage that according to a preferred embodiment of the invention the performance time of the similarity join can be reduced by selecting the dimensions which dynamically and most efficiently partition the space, and the number of dimensions by using the distribution values for respective axes of the given data sets.
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A partition-based high dimensional similarity join method allowing similarity to be efficiently measured by beforehand dynamically selecting space partitioning dimensions and the number of the partitioning dimensions using a dimension selection algorithm. A method of efficiently performing similarity join for high dimensional data during a relatively short period of time without requiring massive storage space. The method includes according to the present invention comprises the steps of partitioning a high dimensional data space and performing joins between predetermined data sets. Dimensions for use in partitioning the high dimensional data space and the number of partitioning dimensions are determined in advance before the space partitioning, and the joins are performed only when respective cells of the data sets are overlapping with each other or are neighboring each other.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is a continuation-in-part of application Ser. No. 12/803,567, filed Jun. 29, 2010, the disclosure of which is incorporated herein by reference.
TECHNICAL FIELD
[0002] This description relates generally to a restraint device and more specifically to a device for physically restraining an individual as well as for selectively applying an electrical shock to control a combative or resistive individual or to deter or repel an attack by an individual or an animal. The device may be utilized by law enforcement personnel as well as by joggers, hikers, bicyclists, animal control officers and others.
BACKGROUND
[0003] There are various non-lethal control, defensive or restraining devices used by law enforcement and others to restrain and control detainees or to ward off an attacker. The simplest of these restraint devices are handcuffs, manacles or shackles which have been available and have been used for many years. Manacles are placed about the wrists of an individual or, in some cases, also placed about the ankles to restrict freedom of motion. While handcuffs and manacles are effective, an individual or detainee, in some instances, can free himself or herself from these devices either by disabling the lock or by manipulation in a manner to free the wrists or ankles.
[0004] More recently other devices have been developed to either restrain or temporarily incapacitate an individual. Aerosol defense sprays containing Capsicum or tear gas are well known. Stun guns use batteries to supply electricity to a circuit which includes multiple transformers which boost the voltage and reduce the amperage and which charge is stored in a capacitor. The capacitor builds up and stores the electrical charge and, upon activation, releases the charge to electrodes which is placed in contact with an individual, causing temporary interference with the individual's nervous system and muscular control to incapacitate the individual.
[0005] A variation of the stun gun is the more recently developed TASER® gun. TASER® devices work in the same basic way as stun guns, except the electrodes are positioned on the end of conductive wires attached to the electrical circuit of the TASER® device. When activated, gas pressure launches the electrodes and the attached wires. Small barbs are affixed to the electrodes so that they will attach to the individual's body or clothing. Electrical current travels through the conductive wires, stunning the individual in basically the same way as a conventional stun gun.
[0006] A main advantage of a TASER® device is that individuals can be brought under control at distances of up to 20 feet. Being able to maintain a distance or space between a detainee or would-be assailant, significantly decreases the risk to law enforcement personnel or intended victims.
[0007] While, as mentioned above, devices such as handcuffs, manacles, shackles, aerosol spray, stun guns and TASER® guns are effective in many situations, they all inherently have certain disadvantages. Accordingly, there exists a need for an effective restraint and control device which law enforcement and other individuals can use to restrain an individual while maintaining a space between the individual and law enforcement personnel. Further, there exists the need for a device of this type which can both provide physical restraint without electrical shock or in the case of more extreme resistance by a detainee, can also apply electrical shock to temporarily disable the individual. While the device has principal application to law enforcement, the device may also be used by civilians as a protective safety device in the event of an attack or threatened attack, as well as by animal control personnel.
[0008] Many of the attendant features will be more readily appreciated as the same becomes better understood by reference to the following detailed description considered in connection with the accompanying drawings.
SUMMARY
[0009] The following presents a simplified summary of the disclosure in order to provide a basic understanding to the reader. This summary is not an extensive overview of the disclosure and it does not identify key/critical elements of the example or delineate the scope of the example. Its sole purpose is to present some concepts disclosed herein in a simplified form as a prelude to the more detailed description that is presented later.
[0010] The present example provides a restraint and control device having an insulated handle at the upper or proximal end and a rod at the distal end which rod is telescopic within the handle so that the overall length of the restraint device can be adjusted. A lockable manacle or cuff is secured to the end of a tether. The manacle or cuff has a fixed arcuate section and a pivotal arm which is engageable in a lock on the fixed section to encircle the limb of an individual. The tether is a wire of stainless steel or other strong material which also serves as an electrical conductor. The end of the tether opposite the cuff is secured to a retractor within the handle. In the retracted position, the cuff is secured at the end of the telescopic rod so that the cuff and the restraint device are an integral, rigid assembly and the tether is fully retracted on to the retractor. In this position, the restraint and control device is rigid and can be attached to the limb of an individual at the cuff or manacle so the movements of the individual can be restrained and controlled by a law enforcement or other individual using the handle while still maintaining the restrained individual at a safe distance.
[0011] The tether can be released to free the cuff from the end of the rod. In this deployed position, the restrained individual will have more freedom of movement, but can still be controlled while maintained at a greater distance from the law enforcement or other individual.
[0012] The upper end of the handle of the restraint and control device houses a battery, transformer, capacitor and circuitry common to stun devices. This circuitry is connected to electrodes on the exterior of the distal end of the rod, as well as electrodes located within the cuff. A trigger, preferably within a trigger guard on the handle, can be operated to cause a high voltage, low amperage discharge to the electrodes which will deliver a disabling or stunning shock to the individual. The electrodes on the distal end of the rod will deter a detainee from attempting to grab the rod to wrestle it away from law enforcement personnel or other user.
DESCRIPTION OF THE DRAWINGS
[0013] The present description will be better understood from the following detailed description read in light of the accompanying drawings, wherein:
[0014] FIG. 1 is a partial perspective view showing the cuff on the distal end of the restraint device secured about the limb of a detainee;
[0015] FIG. 2 is a perspective view of the restraint device of the present example shown in a retracted, rigid position;
[0016] FIG. 3 is a partial perspective view showing the distal end of the restraint device of the present example secured about the limb of an individual in a position with the tether deployed;
[0017] FIG. 4 is a perspective view of the restraint device of the present example showing the telescopic extension of the rod and of the cuff from the handle;
[0018] FIG. 5 is a perspective view similar to FIG. 4 showing the distal rod end retracted and the tether and cuff deployed, the rod being provided with electrodes for applying a stun or electrical shock to a detainee;
[0019] FIG. 6 is a sectional view taken along line 6 - 6 of FIG. 4 ;
[0020] FIG. 7 is a sectional view taken along line 7 - 7 of FIG. 5 ;
[0021] FIG. 8 is a schematic diagram showing the components of the electrical circuit housed within the handle of the restraint device as shown in FIG. 5 ; and
[0022] FIG. 9 is a detail view of the handle broken away to illustrate the retractor in the handle of the device for deploying and taking up the tether.
[0023] FIG. 10 shows an alternative example of a wireless controlled restraint and control device.
[0024] FIG. 11 is a perspective view of the restraint device of the including a compound telescopic extension of the rod and of the cuff from the handle.
[0025] Like reference numerals are used to designate like parts in the accompanying drawings.
DETAILED DESCRIPTION
[0026] The detailed description provided below in connection with the appended drawings is intended as a description of the present examples and is not intended to represent the only forms in which the present example may be constructed or utilized. The description sets forth the functions of the example and the sequence of steps for constructing and operating the example. However, the same or equivalent functions and sequences may be accomplished by different examples.
[0027] The examples below describe a restraint device. Although the present examples are described and illustrated herein as being implemented in a ankle restraint system, the system described is provided as an example and not a limitation. As those skilled in the art will appreciate, the present examples are suitable for application in a variety of different types of restraint systems applicable to various extremities, and portions of those extremities.
[0028] FIG. 1 is a partial perspective view showing the cuff on the distal end of the restraint device secured about the limb of a detainee. The manacle 20 , may be secured about a limb L such as an arm or a leg. Advantageously the manacle 20 may be applied without an officer, or other user having to be in close proximity either in attaching the manacle, or after it is applied. The manacle may be made in various sizes for us with humans and animals of various sizes. Use of eh restraint and control device advantageously allows an electrical stunning device to be used without having to apply electrodes to a torso. Such electrode placement away from the torso should greatly reduce risk of heart attack in those who have had a electrical stun applied to them.
[0029] FIG. 2 is a perspective view of the restraint device of the present example shown in a retracted, rigid position. The restraint and control device of the present example is shown and is generally designated by the numeral 10 .
[0030] The restraint device 10 has an elongate, generally tubular body 12 having a handle 14 at its upper proximal end and a lower, distal end 16 . The handle 14 may be a strong, lightweight non-conductive material such as a fiberglass or a polymeric composite, or the like. The tubular shape may be round as shown, but this is not limiting as the tube could have a square, elliptical, rectangular or other shaped outline.
[0031] At an upper end of the body 12 a handle may be disposed. The upper end of the handle 14 may be contoured having recesses 18 to receive the fingers of the user. The handle 14 may also be provided with a resilient covering, both for comfort of the user and which covering is insulated to protect the user from electrical shock.
[0032] A manacle or cuff 20 is positioned at the lower end 16 of the body 12 . The manacle 20 may include a lock body 22 , preferably of the double locking type, which has internal ratchet teeth 24 operable by a key (not shown) inserted in the lock opening 26 and rotated to open the ratchet teeth 24 and release the bolt of a double locking type lock. A fixed, generally arcuate arm 30 extends from one side of the lock body and is pivotally secured to arm 32 at pivot 36 . A torsion spring 38 may be provided at pivot 36 to bias or urge the arm 32 to the open position when the arm 32 is unlocked. The distal end of arm 32 is provided with teeth 35 which are engageable with the ratchet teeth within the lock body and, in the locked position, the arm is prevented from opening and also prevented from further tightening. Handcuff locks of this type are known to those skilled in the art.
[0033] When the cuff 20 is placed about the limb of an individual, as shown in FIG. 1 , and locked, the restraint device is rigid and can be used to restrain and control the movements of an individual. The cuff 20 can be opened at key lock 26 and the arm 32 will move to the open position under the influence of the spring 38 . The user can engage the fixed arcuate section 30 about the limb of an individual and a quick, smart “snapping” wrist action will cause the locking arm 32 to be engaged in the lock so that the user does not have to bend down or come into close proximity with a restrained individual. Being able to maintain a distance from the individual to be restrained is a safety precaution and diminishes the possibility that the restrained individual can, in some manner, overcome or successfully resist restraint.
[0034] The restraint device 10 can be a unitary piece, but it may advantageously be constructed as two pieces coupled by a tether that provides additional advantages in use. In the two piece unit described herein, the manacle 20 couples to the body 12 by being shaped to fit in a receiving aperture disposed in the lower end of the body 12 . The device 10 may remain rigid during application, and afterwards, if desired separated into two coupled pieces, coupled by a tether (not shown) to allow greater mobility. Separation may be accomplished by depressing a release 95 , disposed in the body 12 .
[0035] FIG. 3 is a partial perspective view showing the distal end of the restraint device of the present example secured about the limb of an individual in a position with the tether deployed. Another feature of the present example is that the restraint allows the handle or body 12 to be loosely tethered to the restrained individual. In this way, the law enforcement officer or other user may maintain a greater distance from the detained individual, but still may maintain control of the detained individual.
[0036] A strong tether cable 80 is connected to the cuff 20 . The cable may be a stainless steel or other wire that extends through the lower tubular elongate body 12 into the upper handle. The cable may incorporate electrical conductors 70 coupled to the electrodes 50 , 50 A, and activated by the officer in alternative examples of the restraint and control device including a TASER®, or other equivalent stunning device.
[0037] Before activation the cuff 20 may be held against a flush cut end of the tube 12 , by the cable tension, as its retraction mechanism may be under spring bias. Being held against the flush cut tube by cable tension may also be augmented by other equivalent coupling mechanisms. For example a cone may be disposed on the manacle so that it retracts and centers when pulled into the hollow center of the tube 12 . Alternatively any sort of aperture may be disposed in either the manacle 20 or tube 12 to recievabally couple to a mating surface provided on the component that will mate with it.
[0038] FIG. 4 is a perspective view of the restraint device of the including a telescopic extension of the rod and of the cuff from the handle. The device may be extensible so the user may adjust the length of the body 12 . A lower rod end 16 is slidable within the tubular body 12 . The lower rod end 16 defines a longitudinally extending slot 40 in which a plurality of bores 42 are provided. A spring-loaded detent pin 46 is provided at the lower end of the handle portion which is engageable in one of the bores to lock the rod at a selected position.
[0039] FIG. 5 is a perspective view of an alternative example of the restraint and control device similar to FIG. 4 . The restraint device of the present example may also be provided with the capability of applying a high voltage, low amperage electrical charge to an individual to assist in restraining or stunning an individual who is resistive or combative.
[0040] The figure shows the distal rod end retracted and the tether and cuff deployed, and further includes the rod being provided with electrodes 50 for applying a stun or electrical shock to a detainee. To provide a shock a conventional circuit such as used in an electric fence, stun gun, or TASER® may be utilized, as in this example by including it in the body 12 .
[0041] The electrical circuit 60 is connected via at least two conductors 70 to the electrodes 50 and, upon discharge, activated by a trigger 55 on the handle will send the electrical charge to the electrodes. The conductors 70 are contained within tether 80 or the tether 80 itself may serve as the conductor between the electrical circuit and the electrodes.
[0042] Additional electrodes 50 A may also be located on the inner side of the arms of the cuff and are shown as fixed arms 30 . A safety may be provided to lock the trigger 55 and prevent inadvertent discharge. The safety is conventionally constructed like a pushbutton safety on a firearms, as is well known to those skilled in the art. Alternatively other types of trigger locks may be used as safety's including bales latches and the like. The charge delivered to the electrodes 50 A on the cuff from the circuit 60 will stun the restrained detainee. The electrodes 50 on the lower end of the body 12 of the device can be placed in contact with an unrestrained individual to subdue the individual. The electrodes 50 will also hold to fend off a restrained individual from attempting to grab the device and wrest it from law enforcement personnel or other user.
[0043] FIG. 6 is a sectional view taken along line 6 - 6 of FIG. 4 and shows the detent pin 46 in an engaged position in one of the bores 42 . The telescopic lower rod end 16 may also be adjusted by other convenient mechanisms such as an adjustable locking slip collar or the like. The body may also be non-adjustable having a fixed length either longer for law enforcement personnel or shorter for civilian use.
[0044] FIG. 7 is a sectional view taken along line 7 - 7 of FIG. 5 and shows electrodes 50 disposed on the body 12 . The body 12 can be provided with two or more pairs of electrodes 50 . However, any number of electrodes, and patterns of electrodes are contemplated, two electrodes typically being a minimum number provided.
[0045] FIG. 8 is a schematic diagram showing the components of the electrical circuit 60 that may be housed within the handle of the restraint device shown in FIG. 5 . The electrodes previously shown may be coupled to an electrical circuit 60 within the handle. The electrical is a stunning circuit, conventionally constructed and may include a battery 62 , voltage amplifier 64 and a capacitor 66 or their equivalents, which are conventional to stun guns and other devices such as TASER® devices. In addition a conventionally constructed wireless receiver and antenna 67 and associated circuitry may be included in the circuit to allow remote activation of the stunning circuit 60 .
[0046] FIG. 9 is a detail view of the handle broken away to illustrate the retractor in the handle of the device for deploying and taking up the tether. The spool can be unlocked allowing the spring-biased spool to rewind the cable to return the cuff to the position shown in FIG. 2 . The user can allow the spool to fully rewind the tether, placing the cuff in a secured position at the lower end of the body.
[0047] The upper end of the body ( 12 of FIG. 2 ) houses a spring-loaded retractor spool 90 upon which the cable 80 is wound. Spring 92 will urge the spool in a direction to wind the cable on the spool. When the law enforcement officer or other user wishes to deploy the cable, a shaft acting as a release 95 will disengage the teeth on the ratchet 98 from the teeth 96 on the spool, allowing the spring-biased spool to freely rotate to pay out or deploy cable 80 when the handle is pulled and the tether cuff engaged about the limb of an individual. Thus, the user can allow the connecting tether cable to extend to a desired length at which point the spool will be locked by ratchet teeth 98 engaging the release maintaining the cable at the desired length in a taut condition.
[0048] Tether 80 is unwound from spool 90 , which may include spring bias by biasing spring 92 . Spring bias is conventionally supplied for taking up the tether, or otherwise retracting it. A ratcheting mechanism is provided by teeth 86 on the edge of spool 90 . Spool teeth may engage with a toothed spool 98 , so that as the tether 80 is extended it is not automatically retracted. The tether may be retracted by pushing an exposed end of shaft 95 that is slidebally disposed in apertures in the handle 12 . Spring bias (not shown) may be provided to return the spool 98 to position. Other equivalent structures for deploying and retracting the tether 80 may be provided that function as described herein.
[0049] The tether 80 may have the conductors 70 disposed on it, or otherwise coupled to it, along its length so that when the tether plays off of the spool the conductors go with it. The conductors may be on the inside, or outside of the tether, or may be incorporated in the tether itself. For example with conductors on the interior the tether may be a woven tubular cable with the insulated conductors included in its core. If on the outside the conductors may be bonded or otherwise coupled to the tether. The tether may be made from any suitable conductive material like a steel braided cable, nonconductive material such as nylon cord, or a combination of materials or their equivalent.
[0050] Conductors 70 may be wound on a spool behind spool 90 , and wound in the opposite direction to the tether 80 so that they unwind into the hollow handle when the tether is extended. This maintains the high voltage connection to the electronics ( 60 of FIG. 8 ) disposed in the handle. Alternatively a contactor arrangement, with brushes or the like may couple the electrical signals from the electronics ( 60 of FIG. 8 ) to the conductors 70 that have been incorporated into the tether 80 .
[0051] Alternatively the conductors 70 may deploy separately from the tether 80 with their own deployment mechanism such as spring wire wound under tension so that the wires tend to quickly play off of a spindle upon which they are wound. Other known equivalent retractor mechanisms including a manually windable retractor spool can be used in alternative examples.
[0052] FIG. 10 shows an alternative example of a wireless controlled restraint and control device. In this example a need for conductors extending from the handle is eliminated as the electronic circuit 60 is part of the previously described cuff 20 . Electrodes 50 A are activated by the trigger 55 activating conventionally constructed transmitter electronics in the body 12 that are coupled wirelessly 1001 to an antenna and receiver electronics that are coupled to the electronic circuit 60 . Optionally electrodes 50 may be incorporated into the body, with an additional electronic circuit (not shown, but as previously described) to create a stun baton after deployment of the cuff 20 . The previously described tether release 94 may be used in this example to release the cuff 20 from the body 12 . Alternatively the tether ( 80 of FIG. 3 ) may be included to provide added control.
[0053] In another alternative example, in the case of a detachable cuff having a wireless ling as shown in FIG. 10 , two cuffs may be included in the device-one at each end, increasing it usefulness for example in riots and crowd control. Controls and circuitry are duplicated as needed to control the additional cuff.
[0054] FIG. 11 is a perspective view of the restraint device of the including a compound telescopic extension of the rod and of the cuff from the handle. The device may be extensible so the user may adjust the length of the body 12 . A lower rod end 16 is slidable within the tubular body 12 in two locations allowing quick deployment. The lower rod end 16 longitudinally extends, and the piece having the catch 46 , also moves away from the body 12 as it extends to an open position.
[0055] It will be obvious to those skilled in the art to make various changes, alterations and modifications to the example described herein. To the extent such changes, alterations and modifications do not depart from the spirit and scope of the appended claims, they are intended to be encompassed therein.
[0056] Those skilled in the art will realize that the process sequences described above may be equivalently performed in any order to achieve a desired result. Also, sub-processes may typically be omitted as desired without taking away from the overall functionality of the processes described above.
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A restraint device having a tubular body with a handle at one end and a telescopic extension rod at the other end which allows the overall length of the body to be selectively adjusted. A cuff is attached to a tether at the end of the rod in a non-deployed position. The tether can be released so a law enforcement officer can loosely control a detainee. Electrical circuitry in the body is connected to electrodes on the lower end of the handle and on the cuff so a disabling charge can be delivered. The device is also useful to civilians as a protective device when jogging, walking, bicycling or the like.
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BACKGROUND OF THE INVENTION
The large quantities of sytrene required by industry are derived by dehydrogenation of ethyl benzene, supplied in part by fractional distillation of hydrocarbon fractions of eight carbon atom aromatics such as those separated from catalytic reformates. The other primary source of ethyl benzene is from alkyalation of benzene, usually with ethylene. The commercial alkylation plants presently in operation employ catalysts of the Friedel-Crafts type, usually aluminum chloride. The liquid catalyst of that type in a stirred reactor makes it possible to remove the heat of reaction by conventional techniques.
The Friedel-Crafts catalysts are highly corrosive and require that reactors, heat exchangers and other auxiliaries by fabricated from expensive corrosion-resistant materials. The spent catalyst and other waste from such plants present a troublesome pollution problem. In addition, the reactants must be very pure to avoid undesirable by-products. In an adaptation of Friedel-Crafts catalyst to the use of catalytic cracking tail gas as source of ethylene for alkylation of benzene, all possibly reactive components other than ethylene must be scrupulously excluded. Hydrogen sulfide, carbon dioxide and water normally present in such tail gas are removable at little cost by caustic scrubbing to absorb the acidic gases hydrogen sulfide and carbon dioxide and by condensation of the water contained in the tail gas or picked up during scrubbing. Carbon monoxide requires much more expensive technique, but obviously must be removed before the gas is brought into contact with a Friedel-Crafts catalyst.
It will be immediately apparent that much of the disadvantage of Friedel-Crafts catalyst will be avoided by the use of a solid heterogeneous catalyst. Many solid porous catalysts having acid character have been shown to be active for the reaction of ethylene with benzene to synthesize ethyl benzene. Typically, the charge to such reaction will be a mixture in which the mole ratio of benzene to ethylene is high enough to suppress the formation of polyethyl benzenes and such amounts of these by-products as may be formed are subjected to transalkylation with benzene, either in the alkylation reactor or in a separate vessel. The acid catalysts are effective for promotion of polymerization. Some alkyl benzenes having larger side chains than ethyl can be found in the product. In addition the activity of the catalyst declines very rapidly, possibly due to formation of high molecular weight compounds which remain on the catalytic surfaces.
It has been shown that zeolites in the nature of zeolite ZSM-5 show high activity and selectivity for alkylation of benzene with ethylene and that catalysts of this type in the acid form remain active for unusually long periods between regenerations to burn off carbonaceous deposits which render the catalyst ineffective. Good discussion of acid zeolite ZSM-5 for this purpose is provided in U.S. Pat. No. 3,751,506, granted Aug. 7, 1973 on an application of George T. Burress. That patent proposes control of the exothermic heat of reaction by conducting the reaction is a series of reactors with intermediate cooling and addition of ethylene between stages. Note is there made that the course of the reaction may be affected by diluents and examples are given in which nitrogen is added in an amount equal to 0.5 mole per mole of ethylene.
SUMMARY OF THE INVENTION
According to the present invention, a reaction mixture of benzene and ethylene is charged to a series of alkylation reactors containing catalyst such as acid zeolite ZSM-5. In addition to the excess of benzene over the stoichiometric value for reaction with ethylene content of the charge, the ethylene is diluted by inert hydrocarbons in an amount greater than equi-molar quantity. Cooling between stages is accomplished by injection of the charge mixture at low temperature, preferably only slightly above the boiling point of benzene at the partial pressure of benzene in the charge mixture as introduced. Activity of the catalyst as measured by conversion of ethylene is very high, catalyst life is prolonged and selectivity to ethyl benzene plus diethyl benzene is excellent under these conditions.
DESCRIPTION OF THE DRAWING
A suitable flow diagram for accomplishing the stated objects of the invention is set out in the single FIGURE of the annexed drawing.
DESCRIPTION OF PREFERRED EMBODIMENTS
In practising the present invention, ethylene is supplied in a diluted form, preferably as a mixture with inert gaseous materials in which ethylene constitutes about 15 to 20 weight percent. A convenient source of such dilute ethylene exists in many oil refineries as tail gas from many units, for example from Fluid Catalytic Cracking (FCC). Typically such tail gases are used as refinery fuel after treating to remove hydrocarbons saleable as components of premium products such as bottled gas (LPG), gasoline or as charge for such process units as alkylation. In addition, the fuel gas is treated to remove the acidic gases hydrogen sulfide which causes pollution of stack gases and carbon dioxide which has no fuel value. It is a particularly valuable feature of the present invention that unreacted inert components of the ethylene diluting medium are fuel gas and may be easily separated from the crude product. The dilute ethylene stream for practice of the present invention requires only the same pretreatment as does fuel gas, whereby the pretreatment of the gas for practice of the invention also prepares the gas to the extent needed for fuel gas use. Note particularly that removal of carbon monoxide, a valuable fuel component, is unnecessary and this gas may be used in the process as diluent and then passed on for fuel use.
The principal diluents are the hydrocarbons methane and ethane, which will be present in an aggregate amount greater than the quantity of ethylene. Other diluents include hydrogen, nitrogen and carbon monoxide. Carbon dioxide is also a diluent and may be retained in the stream if desired, however it is readily removed with treatment to remove hydrogen sulfide and is preferably taken out to upgrade off-gas from the process for fuel use. Water and hydrogen sulfide are tolerable if more rapid aging of the catalyst is acceptable, but these are moderately detrimental in the process and must be removed in any event before supply of the off-gas to furnaces and the like.
A suitable dilute ethylene stream for use in process is prepared by scrubbing tail gas from the usual gas plant of an FCC Unit with aqueous caustic to remove hydrogen sulfide and carbon dioxide. The washed gas is cooled to condense water and any residual hydrocarbons of more than two carbon atoms. The treated gas had the following composition.
______________________________________methane 37 vol %ethane 19ethylene 19hydrogen 9nitrogen 13carbon monoxide 3 100______________________________________
The said dilute ethylene stream was supplied by line 10 to apparatus shown diagramatically in the drawing. Fresh benzene entered the system at line 11 to mix with recycle benzene from line 12 and provide a blended stream of benzene in line 13. One portion of the dilute ethylene stream is mixed with polyalkyl aromatics recycled by line 14 and the blend is mixed with a portion of the benzene from line 13 to provide an aromatics to ethylene ratio by weight of 70. That mixture is admitted to stage 1 of a reactor 15 at 260 pounds per square inch gauge (psig) and 785° F.
The reactor 15 is provided with four beds of HZSM-5, each designated as a "stage" with plenum chambers between the beds for introduction of cool reactants.
The balance of the dilute ethylene from line 10 and the balance of the benzene from line 13 are mixed in pipe 16 and supplied in three portions to the plenum chambers following stages 1, 2 and 3 to cool effluent from the preceding stage to about 785° F. and supply fresh reactants. In each stage the temperature rises to about 820° F. due to the exothermic nature of the reaction.
Effluent from stage 4 of reactor 15 is cooled and passed to a flash drum 16 from which unreacted diluent is withdrawn to be used as fuel. Condensate from drum 16 is then passed by line 17 to a benzene recovery fractionator 18 from which unreacted benzene is taken overhead to line 12 for recycle as described. Bottoms from fractionator 18 are transferred to fractionator 19 from which ethyl benzene is taken overhead as product at line 20. The bottoms from fractionator 19 are transferred in part to a stripper 20 from which polyethyl benzenes are taken overhead and returned to fractionator 19. Materials heavier than polyethyl benzene are rejected as bottoms from stripper 20. The main stream of bottoms from fractionator is returned by line 14 to the inlet of reactor 15 where the polyethyl benzenes undergo transalkylation reactions with benzene.
The crude ethyl benzene product taken overhead from fractionator 19 had the following composition:
______________________________________C.sub.6 non-aromatics 0.005 wt. %benzene 2.345toluene 0.254ethyl benzene 97.166p-xylene 0.090m-xylene 0.102styrene 0.010o-xylene 0.016C.sub.9.sup.+ 0.012 100.000______________________________________
It will be readily apparent to those skilled in the art that benzene and toluene can be reduced to very low levels by redistillation to provide ethyl benzene at better than 99.5% purity. The yield, based on ethylene consumed is 99.5% by weight at weight hourly space velocity (based on ethylene) of 5.
The zeolite catalysts utilized are members of a novel class of zeolites exhibiting some unusual properties. The zeolites induce profound transformations of aliphatic hydrocarbons to aromatic hydrocarbons in commercially desirable yields and are generally highly effective in conversion reactions involving aromatic hydrocarbons. Although they have unusually low alumina contents, i.e. high silica to alumina ratios, they are very active even when the silica to alumina ratio exceeds 30. The activity is surprising since catalytic activity is generally attributed to framework aluminum atoms and cations associated with these aluminum atoms. These zeolites retain their crystallinity for long periods in spite of the presence of steam at high temperatures which induces irreversible collapse of the framework of other zeolites, e.g. of the X and A type. Furthermore, carbonaceous deposits, when formed, may be removed by burning at higher than usual temperatures to restore activity. In many environments the zeolites of this class exhibit very low coke forming capability, conducive to very long times on stream between burning regenerations.
An important characteristic of the crystal structure of this class of zeolites is that it provides constrained access to, and egress from the intracrystalline free space by virtue of having a pore dimension greater than about 5 Angstroms and pore windows of about a size such as would be provided by 10-membered rings of oxygen atoms. It is to be understood, of course, that these rings are those formed by the regular disposition of the tetrahedra making up the anionic framework of the crystalline aluminosilicate, the oxygen atoms themselves being bonded to the silicon or aluminum atoms at the centers of the tetrahedra. Briefly, the preferred type zeolites useful in this invention possess, in combination: a silica to alumina mole ratio of at least about 12; and a structure providing constrained access to the crystalline free space.
The silica to alumina ratio referred to may be determined by conventional analysis. This ratio is meant to represent, as closely as possible, the ratio in the rigid anionic framewrok of the zeolite crystal and to exclude aluminum in the binder or in cationic or other form within the channels. Although zeolites with a silica to alumina ratio of at least 12 are useful, it is preferred to use zeolites having higher ratios of at least about 30. Such zeolites, after activation, acquire an intracrystalline sorption capacity for normal hexane which is greater than that for water, i.e. they exhibit "hydrophobic" properties. It is belived that this hydrophobic character is advantageous in the present invention.
The type zeolites useful in this invention freely sorb normal hexane and have a pore dimension greater than about 5 Angstroms. In addition, the structure must provide constrained access to larger molecules. It is sometimes possible to judge from a known crystal structure whether such constrained access exists. For example, if the only pore windows in a crystal are formed by 8-membered rings of oxygen atoms, then access by molecules of larger cross-section than normal hexane is excluded and the zeolite is not of the desired type. Windows of 10-membered rings are preferred, although, in some instances, excessive puckering or pore blockage may render these zeolites ineffective. Twelve-membered rings do not generally appear to offer sufficient constraint to produce the advantageous conversions, although puckered structures exist such as TMA offretite which is a known effective zeolite. Also, structures can be conceived, due to pore blockage or other cause, that may be operative.
Rather than attempt to judge from crystal structure whether or not a zeolite possesses the necessary constrained access, a simple determination of the "constraint index" may be made by passing continuously a mixture of an equal weight of normal hexane and 3-methylpentane over a small sample, approximately 1 gram or less, of catalyst at atmospheric pressure according to the following procedure. A sample of the zeolite, in the form of pellets or extrudate, is crushed to a particle size about that of coarse sand and mounted in a glass tube. Prior to testing, the zeolite is treated with a stream of air at 1000° F. for at least 15 minutes. The zeolite is then flushed with helium and the temperature adjusted between 550° F. and 950° F. to give an overall conversion between 10% and 60%. The mixture of hydrocarbons is passed at 1 liquid hourly space velocity (i.e., 1 volume of liquid hydrocarbon per volume of zeolite per hour) over the zeolite with a helium dilution to give a helium to total hydrocarbon mole ratio of 4:1. After 20 minutes on stream, a sample of the effluent is taken and analyzed, most conveniently by gas chromotography, to determine the fraction remaining unchanged for each of the two hydrocarbons.
The "constraint index" is calculated as follows: ##EQU1##
The constraint index approximates the ratio of the cracking rate constants for the two hydrocarbons. Zeolites suitable for the present invention are those having a constraint index in the approximate range of 1 to 12. Constraint Index (CI) values for some typical zeolites are:
______________________________________CAS C.I.______________________________________ZSM-5 8.3ZSM-11 8.7ZSM-12 2ZSM-38 2ZSM-35 4.5TMA Offretite 3.7Beta 0.6ZSM-4 0.5H-Zeolon 0.4REY 0.4Amorphous Silica-Alumina 0.6Erionite 38______________________________________
It is to be realized that the above constraint index values typically characterize the specified zeolites but that such as the cumulative result of several variables used in determination and calculation thereof. Thus, for a given zeolite depending on the temperature employed within the aforenoted range of 550° F. to 950° F., with accompanying conversion between 10% and 60%, the constraint index may vary within the indicated approximate range of 1 to 12. Likewise, other variables such as the crystal size of the zeolite, the presence of possible occluded contaminants and binders intimately combined with the zeolite may affect the constraint index. It will accordingly be understood by those skilled in the art that the constraint index, as utilized herein, while affording a highly useful means for characterizing the zeolites of interest is approximate, taking into consideration the manner of its determination, with probability, in some instances, of compounding variable extremes. However, in all instances, at a temperature within the above-specified range of 550° F. to 950° F., the constraint index will have a value for any given zeolite of interest herein within the approximate range of 1 to 12.
The class of zeolites defined herein is exemplified by ZSM-5, ZSM-11, ZSM-12, ZSM-35, ZSM-38 and other similar materials. U.S. Pat. No. 3,702,886 describing and claiming ZSM-5 is incorporated herein by reference.
ZSM-11 is more particularly described in U.S. Pat. No. 3,709,979, the entire contents of which are incorporated herein by reference.
ZSM-12 is more particularly described in U.S. Pat. No. 3,832,449, the entire contents of which are incorporated herein by reference.
ZSM-38 is more particularly described in U.S. application Ser. No. 528,060, filed Nov. 29, 1974. This zeolite can be identified, in terms of mole ratios of oxides and in the anhydrous state, as follows:
(0.3-2.5)R.sub.2 O: (0-0.8)M.sub.2 O : Al.sub.2 O.sub.3 : > 8 SiO.sub.2
wherein R is an organic nitrogen-containing cation derived from a 2-(hydroxyalkyl) trialkylammonium compound and M is an alkali metal cation, and is characterized by a specified X-ray powder diffraction pattern.
In a preferred synthesized form, the zeolite has a formula, in terms of mole ratios of oxides and in the anhydrous state, as follows:
(0.4-2.5)R.sub.2 O : (0-0.6)M.sub.2 O : Al.sub.2 O.sub.3 : xSiO.sub.2
wherein R is an organic nitrogen-containing cation derived from a 2-hydroxyalkyl) trialkylammonium compound, wherein alkyl is methyl, ethyl or a combination thereof, M is an alkali metal, especially sodium, and x is from greater than 8 to about 50.
The synthetic ZSM-38 zeolite possesses a definite distinguishing crystalline structure whose X-ray diffraction pattern shows substantially the significant lines set forth in Table I. It is observed that this X-ray diffraction pattern (significant lines) is similar to that of natural ferrierite with a notable exception being that natural ferrierite patterns exhibit a significant line at 11.33A.
TABLE I______________________________________d (A) I/Io______________________________________9.8 ± 0.20 Strong9.1 ± 0.19 Medium8.0 ± 0.16 Weak7.1 ± 0.14 Medium6.7 ± 0.14 Medium6.0 ± 0.12 Weak4.37 ± 0.09 Weak4.23 ± 0.09 Weak4.01 ± 0.08 Very Strong3.81 ± 0.08 Very Strong3.69 ± 0.07 Medium3.57 ± 0.07 Very Strong3.51 ± 0.07 Very Strong3.34 ± 0.07 Medium3.17 ± 0.06 Strong3.08 ± 0.06 Medium3.00 ± 0.06 Weak2.92 ± 0.06 Medium2.73 ± 0.06 Weak2.66 ± 0.05 Weak2.60 ± 0.05 Weak2.49 ± 0.05 Weak______________________________________
A further characteristic of ZSM-38 is its sorptive capacity providing said zeolite to have increased capacity for 2-methylpentane (with respect to n-hexane sorption by the ratio n-hexane/2-methyl-pentane) when compared with a hydrogen form of natural ferrierite resulting from calcination of an ammonium exchanged form. The characteristic sorption ratio n-hexane/2-methylpentane for ZSM-38 (after calcination at 600° L C.) is less than 10, whereas that ratio for the natural ferrierite is substantially greater than 10, for example, as high as 34 or higher.
Zeolite ZSM-38 can be suitably prepared by preparing a solution containing sources of an alkali metal oxide, preferably sodium oxide, an organic nitrogen-containing oxide, an oxide of aluminum, an oxide of silicon and water and having a composition, in terms of mole ratios of oxides, falling within the following ranges:
______________________________________ R+ Broad Preferred______________________________________R+ + M+ 0.2 - 1.0 0.3 - 0.9OH.sup.- /SiO.sub.2 0.05 - 0.5 0.07 - 0.49H.sub.2 O/OH.sup.- 41 - 500 100 - 250SiO.sub.2 /Al.sub.2 O.sub.3 8.8 - 200 12 - 60______________________________________
wherein R is an organic nitrogen-containing cation derived from a 2-(hydroxyalkyl) trialkylammonium compound and M is an alkali metal ion, and maintaining the mixture until crystals of the zeolite are formed. (The quantity of OH - is calculated only from the inorganic sources of alkali without any organic base contribution). Thereafter, the crystals are separated from the liquid and recovered. Typical reaction conditions consist of heating the foregoing reaction mixture to a temperature of from about 90° C. to about 400° C. for a period of time of from about 6 hours to about 100 days. A more preferred temperature range is from about 150° C. to about 400° C. with the amount of time at a temperature in such range being from about 6 hours to about 80 days.
The digestion of the gel particles is carried out until crystals form. The solid product is separated from the reaction medium, as by cooling the whole to room temperature, filtering and water washing. The crystalline product is thereafter dried, e.g. at 230° F. for from about 8 to 24 hours.
ZSM-35 is more particularly described in U.S. application Ser. No. 528,061, filed Nov. 29, 1974. This zeolite can be identified, in terms of mole ratios of oxides and in the anhydrous state, as follows:
(0.3-2.5)R.sub.2 O : (0-0.8)M.sub.2 O : Al.sub.2 O.sub.3 : > 8 SiO.sub.2
wherein R is an organic nitrogen-containing cation derived from ethylenediamine or pyrrolidine and M is an alkali metal cation, and is characterized by a specified X-ray powder diffraction pattern.
In a preferred synthesized form the zeolite has a formula, in terms of mole ratios of oxides and in the anhydrous state, as follows:
(0.4-2.5)R.sub.2 O : (0.0.6)M.sub.2 O : A1.sub.2 O.sub.3 : xSiO.sub.2
wherein R is an organic nitrogen-containing cation derived from ethylenediamine or pyrrolidine, M is an alkali metal, especially sodium, and x is from greater than 8 to about 50.
The synthetic ZSM-35 zeolite possesses a definite distinguishing crystalline structure whose X-ray diffraction pattern shows substantially the significant lines set forth in Table II. It is observed that this X-ray diffraction pattern (with respect to significant lines) is similar to that of natural ferrierite with a notable exception being that natural ferrierite patterns exhibit a significant line at 11.33A. Close examination of some individual samples of ZSM-35 may show a very weak line at 11.3-11.5A. This very weak line, however, is determined not to be a significant line for ZSM-35.
TABLE II______________________________________d (A) I/Io______________________________________9.6 ± 0.2 Very Strong- Very Very Strong7.10 ± 0.15 Medium6.98 ± 0.14 Medium6.64 ± 0.14 Medium5.78 ± 0.12 Weak5.68 ± 0.12 Weak4.97 ± 0.10 Weak4.58 ± 0.09 Weak3.99 ± 0.08 Strong3.94 ± 0.08 Medium Strong3.85 ± 0.08 Medium3.78 ± 0.08 Strong3.74 ± 0.08 Weak3.66 ± 0.07 Medium3.54 ± 0.07 Very Strong3.48 ± 0.07 Very Strong3.39 ± 0.07 Weak3.32 ± 0.07 Weak Medium3.14 ± 0.06 Weak Medium2.90 ± 0.06 Weak2.85 ± 0.06 Weak2.71 ± 0.05 Weak2.65 ± 0.05 Weak2.62 ± 0.05 Weak2.58 ± 0.05 Weak2.54 ± 0.05 Weak2.48 ± 0.05 Weak______________________________________
A further characteristic of ZSM-35 is its sorptive capacity proving said zeolite to have increased capacity for 2-methylpentane (with respect to n-hexane sorption by the ratio n-hexane/2-methylpentane) when compared with a hydrogen form of natural ferrierite resulting from calcination of an ammonium exchanged form. The characteristic sorption ration-hexane/2-methylpentane for ZSM-35 (after calcination at 600° C.) is less than 10, whereas that ratio for the natural ferrierite is substantially greater than 10, for example, as high as 34 or higher.
Zeolite ZSM-35 can be suitably prepared by preparing a solution containing sources of an alkali metal oxide, preferably sodium oxide, and organic nitrogen-containing oxide, an oxide of aluminum, an oxide of silicon and water and having a composition, in terms of mole ratios of oxides, falling within the following ranges:
______________________________________ R+ Broad Preferred______________________________________R+ + M+ 0.2 - 1.0 0.3 - 0.9OH.sup.- /SiO.sub.2 0.05 - 0.5 0.07 - 0.49H.sub.2 O/OH.sup.- 41 - 500 100 - 250SiO.sub.2 /Al.sub.2 O.sub.3 8.8 - 200 12 - 60______________________________________
wherein R is an organic nitrogen-containing cation derived from pyrrolidine or ethylenediamine and M is an alkali metal ion, and maintaining the mixture until crystals of the zeolite are formed. (The quantity of OH - is calculated only from the inorganic sources of alkali without any organic base contribution). Thereafter, the crystals are separated from the liquid and recovered. Typical reaction conditions consist of heating the foregoing reaction mixture to a temperature of from about 90° C. to about 400° C. for a period of time of from about 6 hours to about 100 days. A more preferred temperature range is from about 150° C. to about 400° C. with the amount of time at a temperature in such range being from about 6 hours to about 80 days.
The digestion of the gel particles is carried out until crystals form. The solid product is separated from the reaction medium, as by cooling the whole to room temperature, filtering and water washing. The crystalline product is dried, e.g. at 230° F., for from about 8 to 24 hours.
The specific zeolites described, when prepared in the presence of organic cations, are catalytically inactive, possibly because the intracrystalline free space is occupied by organic cations from the forming solution. They may be activated by heating in an inert atmosphere at 1000° F. for one hour, for example, followed by base exchange with ammonium salts followed by calcination at 1000° F. in air. The presence of organic cations in the forming solution may not be absolutely essential to the formation of this type zeolite; however, the presence of these cations does appear to favor the formation of this special type of zeolite. More generally, it is desirable to activate this type catalyst by base exchange with ammonium salts followed by calcination in air at about 1000° F. for from about 15 minutes to about 24 hours.
Natural zeolites may sometimes be converted to this type zeolite catalyst by various activation procedures and other treatments such as base exchange, steaming, alumina extraction and calcination, in combinations. Natural minerals which may be so treated include ferrierite, brewsterite, stilbite, dachiardite, epistilbite, heulandite, and clinoptilolite. The preferred crystalline aluminosilicates are ZSM-5, ZSM-11, ZSM-12, ZSM-38 and ZSM-35, with ZSM-5, particularly preferred.
In a preferred aspect of this invention, the zeolites hereof are selected as those having a crystal framework density, in the dry hydrogen form, of not substantially below about 1.6 grams per cubic centimeter. It has been found that zeolites which satisfy all three of these criteria are most desired because they tend to maximize the production of gasoline boiling range hydrocarbon products. Therefore, the preferred zeolites of this invention are those having a constraint index as defined above of about 1 to about 12, a silica to alumina ratio of at least about 12 and a dried crystal density of not less than about 1.6 grams per cubic centimeter. The dry density for known structures may be calculated from the number of silicon plus aluminum atoms per 1000 cubic Angstroms, as given, e.g., on Page 19 of the article on Zeolite Structure by W. M. Meier. This paper, the entire contents of which are incorporated herein by reference, is included in "Proceedings of the Conference on Molecular Sieves, London, April 1967," published by the Society of Chemical Industry, London, 1968. When the crystal structure is unknown, the crystal framework density may be determined by classical pyknometer techniques. For example, it may be determined by immersing the dry hydrogen form of the zeolite in an organic solvent which is not sorbed by the crystal. It is possible that the unusual sustained activity and stability of this class of zeolites is associated with its high crystal anionic framework density of not less than about 1.6 grams per cubic centimeter. This high density, of course, must be associated with a relatively small amount of free space within the crystal, which might be expected to result in more stable structures. This free space, however, is important as the locus of catalytic activity.
Crystal framework densities of some typical zeolites are:
______________________________________ Void FrameworkZeolite Volume Density______________________________________Ferrierite 0.28 cc/cc 1.76 g/ccMordenite .28 1.7ZSM-5, -11 .29 1.79Dachiardite .32 1.72L .32 1.61Clinoptilolite .34 1.71Laumontite .34 1.77ZSM-4 (Omega) .38 1.65Heulandite .39 1.69P .41 1.57Offretite .40 1.55Levynite .40 1.54Erionite .35 1.51Gmelinite .44 1.46Chabazite .47 1.45A .5 1.3Y .48 1.27______________________________________
When synthesized in the alkali metal form, the zeolite is conveniently converted to the hydrogen form, generally by intermediate formation of the ammonium form as a result of ammonium ion exchange and calcination of the ammonium form to yield the hydrogen form. In addition to the hydrogen form, other forms of the zeolite wherein the original alkali metal has been reduced to less than about 1.5 percent by weight may be used. Thus, the original alkali metal of the zeolite may be replaced by ion exchange with other suitable ions of Groups IB to VIII of the Period Table, including, by way of example, nickel, copper, zinc, palladium, calcium or rare earth metals.
In practicing the desired conversion process, it may be desirable to incorporate the above described crystalline aluminosilicate zeolite in another material resistant to the temperature and other conditions employed in the process. Such matrix materials include synthetic or naturally occurring substances as well as inorganic materials such as clay, silica and/or metal oxides. The latter may be either naturally occurring or in the form of gelantinous precipitates or gels including mixtures of silica and metal oxides. Naturally occurring clays which can be composited with the zeolite include those of the montmorillonite and kaolin families, which families include the sub-bentonites and the kaolins commonly known as Dixie, McNamee-Georgia and Florida clays or others in which the main mineral constituent is halloysite, kaolinite, dickite, nacrite or anauxite. Such clays can be used in the raw state as originally mined or initially subjected to calcination, acid treatment or chemical modification.
In addition to the foregoing materials, the zeolites employed herein may be composited with a porous matrix material, such as alumina, silica-alumina, silica-magnesia, silica-zirconia, silica-thoria, silica-berylia, silica-titania as well as ternary compositions, such as silica-alumina-thoria, silica-alumina-zirconia, silica-alumina-magnesia and silica-magnesia-zirconia. The matrix may be in the form of a cogel. The relative proportions of zeolite component and inorganic oxide gel matrix may vary widely with the zeolite content ranging from between about 1 to about 99% by weight and more usually in the range of about 5 to about 80% by weight of the composite.
Indications are that the catalyst will show very slow aging in this configuration. This conclusion is based on semi-commercial scale comparisons among adiabatic runs comparing alkylation of benzene over HZSM-5 with pure (polymer grade) ethylene and with ethylene diluted in the manner described above. Temperature probes in the adiabatic semicommercial reactor report a migration of the zone of maximum temperature downward through the down-flow reactor when charging polymer grade ethylene. The zone of maximum temperature is considered to be the zone of maximum (exothermic) reaction and it is concluded that catalyst ages as the zone moves downward. That effect is seen to a much lesser degree when charging the above-described dilute ethylene to the adiabatic reactor. Instead, the zone of maximum temperature in the catalyst bed remains quasi-stationary with a much lower rate of movement. This can lead logically to the conclusion that the catalyst is aging at a far less rapid rate.
The process of this invention is conducted such that alkylation of the aromatic hydrocarbon compound, benzene, with ethylene, is carried out in the vapor-phase by contact in a reaction zone under alkylation effective conditions, said catalyst being characterized as above zeolite which has been hydrogen exchanged such that a predominate portion of its exchangeable cations are hydrogen ions. In general, it is contemplated that more than 50% and preferably more than 75% of the cationic sites of the ZSM-5 zeolite will be occupied by hydrogen ions. The alkylatable aromatic compound and alkylating agent are desirably fed to a first stage at an appropriate mole ratio of one to the other. The feed to such first stage is heated. After reaction takes place, the effluent of the first stage is cooled to remove heat of reaction by addition of reactants. A plurality of reaction stages are possible for the process of this invention. It is generally desirable to provide cooling between reactor stages by addition of cool reactant.
In vapor-phase alkylation of benzene with ethylene, the first stage mole ratio of benzene to ethylene may be in the range of about 1:1 to about 30:1. The first stage feed is heated to a reactor inlet temperature within the range of about 650° F to about 900° F at a pressure within the range of about atmospheric to about 3000 p.s.i.g. Preferred inlet temperatures fall within the range of about 700° F to about 850° F and preferred pressures fall within the range of about 25 p.s.i.g. to about 450 p.s.i.g. The repeating of reaction staging is carried out while maintaining an overall aromatic hydrocarbon, e.g. benzene, to alkylating agent, e.g. ethylene, mole ratio of about 1:1 to about 30:1, with a preferred range of about 2.5:1 to about 25:1. As the reaction proceeds through the stages, the aromatic:alkylating agent mole ratio is held constant by changes in the ratio in the fresh interstage feed.
It is noted that extremely high total feed space velocities are possible in the process of this invention, i.e. up to 800 lb. total feed/hr-lb. crystalline aluminosilicate. An important factor in the present process is, however, the weight hourly space velocity (WHSV) of the alkylating agent, e.g. ethylene. The alkylating agent WHSV to each of any alkylation reactor stages is maintained between about 1 and about 10 lb. alkylating agent/hr-lb. crystalline aluminosilicate. The most desirable ethylene WHSV is within the range of about 2 to about 6 lb. ethylene/hr-lb. crystalline aluminosilicate. When the ethylene WHSV is maintained within the above limits, an economical cycle between regenerations of catalyst exists.
Operating in the manner described, run lengths of up to 29 days have been achieved, all terminated for reasons other than deactivation of the catalyst. It will be clear immediately that dilution of ethylene in the degree described increases the heat capacity of the system with resultant lower temperature rise across each catalyst bed. Also achieved is reduction in partial pressure of ethylene thus reducing polymerization of that olefin and subsequent formation of by-products such as butyl benzene. The inert hydrocarbons increase the partial pressure driving force to desorb coke precursors from the catalyst surface and thus reduce aging rate.
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Benzene and dilute ethylene are reacted in vapor phase over solid porous catalyst such as zeolite ZSM-5 in a series of reaction zones with intermediate injection of cold reactants and diluent to control temperature.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to mining machines utilized in longwall mining operations and, more particularly, to an improved drum-cutter mining machine utilizing an auxiliary cutting drum for operating on mined material carried by a conveyor used for supporting the mining machine.
2. Description of the Prior Art
Underground mining operations frequently utilize a mining process referred to as longwall mining in order to most efficiently shear a mineral from a mineral seam.
Longwall mining procedures utilize a drum-cutter mining machine, also referred to as a shearer loader, which is positioned proximate to a mineral seam in a mine wall. The drum-cutter mining machine includes a machine body and cutting drums rotatably supported by support arms extending from opposite ends of the machine body wherein the support arms are pivotally connected to the machine body. The support arms are pivoted about their respective pivotal connections to the machine body in order to position the cutting drums at desired cutting heights. Preferably, a first drum, the leading cutting drum, is positioned to shear an upper portion of the mineral seam, and a second drum, the trailing cutting drum, is positioned to cut a lower portion of the mineral seam along the floor of the mine. By pivoting the respective support arms about their pivotal connections to the machine body, the vertical positioning of the respective cutting drums may be altered. When the mineral is to be sheared from the mine seam, drive motors provide rotational torque to the respective cutting drums. The leading cutting drum thereby shears a first portion of the mine wall, and the trailing cutting drum shears a second portion of the mine wall. The drum-cutter mining machine is translated along the length of the mine seam face upon a longwall conveyor system that includes a rack structure supported by the conveyor and extending along the entire length of the mine wall face. A drive motor in the machine body drives gearing to meshingly engage with individual rack pins of the rack structure to thereby allow translation of the mining machine therealong.
West German Pat. No. 35 27 253 discloses a drum-cutter mining machine equipped with an auxiliary cutting drum. The mining machine is movable along a longwall conveyor. Two support arms pivotally supported by the frame of the mining machine at opposite ends thereof rotatable support cutting drums. The cutting drums are situated on the side of the support arms which face the coal face, and on the opposite side, the goaf side, the cutting drums support drive motors which are connected by gearing to the respective cutting drums for rotation thereof. The cutting drum and the drive motor are arranged on each of the support arms such that the rotational axis of the motor and the rotational axis of the cutting drum are parallel to each other. A jib is pivotally supported on the front free face of the motor. An actuator also extends between the jib and the front face of the motor to impart pivotal movements to the jib. The end of the jib projecting below the drive motor and under the cutting drum carries an auxiliary drum which is drivingly connected by gearing to a butt shaft portion of the motor shaft at the goaf side of the support arm. The connection between the auxiliary drum and the drive motor is formed by a train of gears that extends inside the jib.
Drum-cutter machines used to release coal from thick mine seams are required to operate with cutting drums having large diameters and also provided with drum support arms having a greater length that extends over the radius of the drum. In this way, the drums can be positioned throughout the entire required range of cutting to release material from the thick mine seam. When mining such thick seams, the material loosened by the cutting drums breaks down in large layers which are caught by the conveying elements of the longwall conveyor and pressed against the area of the mining machine bridging the conveyor. This condition leads to jamming, the creation of obstructions and interruptions to working of the mine seam.
The support arms of such a drum-cutter mining machine have a length required to carry the cutting drum through a large pivotal movement in order to cut away coal at the roof of the coal seam while the mining machine travels in one direction, and to cut away coal at the floor of the mine seam through operation of the same cutting drum when the direction of travel by the mining machine is reversed. The drive motor for the cutting drum participates in the pivotal movement of the support arm because it is fastened to the support arm and also carries the jib which is connected thereto as well as the auxiliary drum which is connected to the jib. For this reason, an adjustment device is necessary to constantly bring the jib into a position in which the auxiliary cutting drum can fulfill its function of breaking up portions of debris on the conveyor at the portion of the mining machine bridging the conveyor.
It is accordingly the object of the present invention to provide a mining machine particularly a mining machine constructed for mining thick seams in which an auxiliary cutting drum may be properly positioned without an independent actuator of the drum positioning actuator.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a drum cutter mining machine for releasing material from a thick mine seam while traversed along a conveyor, the drum cutter mining machine including the combination of: a machine body including body portion traversing the conveyor above a material transportation portion while moving back and forth along the conveyor; a support arm pivotally connected to the machine body at an end thereof for leading and trailing with respect to movement of the machine body along the conveyor; a cutting drum rotatably supported by an extended end portion of the support arm for releasing material from the mine seam; a drive motor for rotating the cutting drum, the drive motor being supported above the conveyor by the support arm for allowing passage of debris on the conveyor beneath the drive motor and the body which bridges the conveyor; a jib secured to a surface of the drive motor which is turned away from the support arm for support thereby; an auxiliary cutting drum rotatably mounted at an extend end of the jib which projects from the drive motor; gear means for drivingly interconnecting the drive motor and the auxiliary cutting drum; the jib having an extended length such that the auxiliary drum is situated thereby below the axis of pivotal movement formed by the pivot when the support arm is in a central position to its range of pivotal movement ranging between operation of the cutting drum at the mine rod and at the mine floor; and means supported by the machine body and connected to the support arm for pivoting the support arm to locate the cutting drum carried thereby for operation at the roof of the mineral seam and at other times at the floor of the mineral seam, the auxiliary cutting drum being concurrently positioned by operation of the means from a position below the pivotal axis to operating positions where the operating height of the auxiliary cutting drum above the conveyor is substantially the same independently of whether the cutting drum is operating at the roof o the floor of the coal seam.
Thus, it can be seen according to the present invention there is provided an improved drum cutter mining machine over the known form of cutting machine described herein by providing that the jib which carries the auxiliary cutting drum is dimensioned as the extended length thereof and arranged such that the auxiliary cutting drum is situated beneath the pivot axis for the support arm when the support arm is positioned midway, centrally, of the range of pivotal movement. Because of this arrangement, the auxiliary cutting drum is situated directly in front of the opening which is beneath the portion of the machine body bridging the conveyor and immediately below the pivotal axis of the support arm. Pivotal movement of the support arm from the central position into operating positions produce only slight variations to the elevated positions at which the auxiliary cutting drum is moved. Thus, it can be seen that a special mechanism required heretofore to compensate for the variations to the operating height of the auxiliary cutting drum at various pivoted positions by the support arm is unnecessary.
According to a further feature of the present invention, the machine body is provided with an inlet situated underneath the pivot axis for the support arm. The inlet has dimensions including the depth of the inlet extending beyond the pivot axis of the support arm determined by the radius of the auxiliary cutting drum and path of pivotal movement of the auxiliary cutting drum produced when the support arm is lowered by one half of the pivotal operating range of the support arm. During descending movement by the support arm, the auxiliary cutting drum moves into the space formed by the inlet without colliding with the frame or body of the mining machine.
It is advantageous to rotatably support both sides of the auxiliary cutting drum from the support arm of the drum cutter loader or an extension of the support arm. The auxiliary cutting drum is carried from the side of the support arm which is turned away from the jib. Such a mounting arrangement increases the resistance capability of the mounting for the auxiliary cutting drum and renders the mounting insensitive to intermittent loads which are unavoidable when coarse debris is produced by the mining operation. To this end, the support arm or a support arm extension can be provided with a detachably arranged shoulder situated on the other side of the arm or arm extension to extend underneath the pivot axis for the arm.
It is possible, however, to design the shoulder and support arm as a unit wherein the support arm shoulder takes the form a housing provided with spur gear wheels which drivingly interconnect the auxiliary drum to a gear train in the support arm. In one arrangement of this type, the gearing which transmits the rotational movement to the auxiliary cutting drum is coordinated with the support arm. The lubrication of the gearing is therefore also provided by the oil supply circuit in the support arm. It is unnecessary to utilize a butt shaft of the drive motor which is otherwise essential according to an arrangement wherein the gearing for the auxiliary drum is situated inside the jib.
An embodiment of the present invention provides that the support arm for the drum cutter loader includes a protective housing connected to the support arm and receiving the drive motor. The housing adjoins the sidewall of the support arm and extends downwardly so that spur gears supported in the housing can drivenly engage the shaft of the auxiliary cutting drum which is to be driven and face toward the support arm. In this instance, the driven shaft of the auxiliary cutting drum is supported by the housing. The gearing interconnects the drive shaft of the auxiliary drum and the butt output shaft of the driving motor. A cover is provided for the jib and the cover retains the end of the drive shaft for the auxiliary cutting drum at the goaf side. The cover seals the protective housing on the front face which is turned away from the support arm. The protective housing is flange mounted on the support arms so that the auxiliary cutting drum is situated underneath the pivotal axis of the support arm when the support arm is in the central pivotal position is of pivotal range.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be better understood when the following description is read in light of the accompanying drawings in which:
FIG. 1 is a partial elevational view of the drum-cutter mining machine according to one embodiment of the present invention;
FIG. 2 illustrates a front view of the drum-cutter mining machine of FIG. 1;
FIG. 3 is an elevational view similar to FIG. 1 and illustrating a further embodiment of the drum-cuter mining machine of the present invention;
FIG. 4 is a plan view of the mining machine of FIG. 3; and
FIG. 5 is a plan view of a further embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the embodiments shown in the drawings, a drum cutter loader 1 is situated above a longwall conveyor means 2, such as a face conveyor, for releasing coal from a mine seam 4, by operation of a cutting drum 3 while the mining machine is traversed along the conveyor. The cutting drum 3 is supported at the extended end of a support arm 5 for rotation about an axis which is generally parallel with the mine floor. The support arm 5 is carried at an end of a machine frame by pivot shaft 6 for pivotal movement about a pivot axis centrally located along the length of the pivot shaft. The pivot shaft extends across the width of the mining machine such that the pivot axis is generally parallel with the mine floor. The cutting drum is positioned by the operation of a piston and cylinder assembly 8 which has its cylinder end mounted by a clevis arrangement to the machine body and the rod end connected to a shoulder 7 that is part of and projects from the support arm 5. Operation of the piston cylinder assembly 8 thus pivots the support arm about shaft 6 to raise the cutter drum to a position where, as shown in FIG. 3, the drum operates to release coal from the mine face while passing along a path of travel at the mine roof. When traversing movement of the mining machine is reversed, then the piston and cylinder assembly 8 is actuated to pivot the support arm downwardly to a position where the cutting drum operates to release coal from the mine face along the path of travel at the mine floor.
A drive motor 9 is mounted to the support arm with the motor drive shaft extending into a hollow interior of the support arm where a gearing 10 is mounted onto the shaft, which gearing inturn meshes with other gearing spaced along the arm 5 in turn drivingly engaging gearing situated in the cutting drum for rotation thereof. In all embodiments of the invention shown in the drawings, the drive motor 9 is situated on the side of the support arm which is turned away from the cutting drum 3. Moreover, the drive motor is also located between the pivot axis formed by pivot 6 and the rotational axis 11 of the cutting drum 3. The motor is firmly mounted to the support arm such that it extends from the arm above the longwall conveyor. The motor is used to provide support by attachment thereto, for a jib 13 which provides support for an auxiliary cutting drum 12 on a front face of the jib which is turned away from the support arm 5. The jib is provided with an internal cavity wherein gearing 14 comprised of a plurality of meshing gear members to transmit rotation of the drive motor 9 to the auxiliary cutting drum. The width of the cutting drum 12 corresponds approximately to the inside width of the conveyor wherein the burden is transported.
In the illustrated embodiments of the invention of FIGS. 1, 4, and 5, the end portion of a shaft 15, used to support the auxiliary cutting drum 12 which is turned away from the jib 13, is supported by a roller bearing 16 that is in turn supported either by shoulder 7 (FIG. 1) or an extension 17 (FIG. 3) to the support arm. The shoulder 7 and support arm 5 can be formed as a single unitary component. However, if desired, shoulder 7 can be detachably connected to support arm 5. It is preferred to provide that gearing 18 (FIG. 1) which drivingly interconnects drive motor 9 with the auxiliary cutting drum 12 be arranged to extend in the shoulder 7 and not in the jib 13, particularly when the support arm 5 and the shoulder 7 comprise a unitary component. The jib 13 and shoulder 7 extend downwardly in a direction of the machine body. The length of the jib 13 and the length of the shoulder 7 are such that the auxiliary cutting drum 12 is situated underneath the pivot axis formed by pivot shaft 6 when the support arm of the cutting drum is located at a central position to the range X of pivotal movement. In the central position of support arm 5, the auxiliary cutting drum 12 forms a circular cutting path that is at least approximately tangent to the top edge of a bridge opening 19 in the machine frame 20.
As can be seen from the dot-lines, in FIG. 1, variations to the pivotal movement of the support arm according to the present invention, bring about only relatively small variations to the changes to the height of the auxiliary cutting drum which are brought about by the dimensioning of the length of the jib 13 and the support arm shoulder 7. Thus, it can be seen that the auxiliary cutting drum 12 is rotatably supported at a predetermined distance below the support arm because of the extended length of the jib 13 engaging one end of the cutting drum and the extended length of the support arm shoulder 7 engaging the other end of the cutting drum. This obviates the need for a special adjusting mechanism to correct positioning of the auxiliary cutting drum for operating at a desired height at a dependent relation to the particular angle to which a support arm is moved for locating the cutting drum at a desired operating site. The front face of the mining machine body, i.e., the portion of the machine body which traverses the conveyor above the material conveying section thereof is provided with surfaces forming an inlet 21 underneath the pivot axis formed by pivot pin 6. The depth of the inlet, i.e., height above the conveyor, starting from the pivot axis of pivot 6 is determined by the radius of the auxiliary cutting drum 12 and by the path of pivotal movement through which the auxiliary drum 12 moves when the support arm 5 is lowered to a lowermost operating position.
A mining machine embodying the features of the present invention is advantageous, particularly for drum-cutter loaders which are modified with parts to enable the use of the loader in thick mine seams. Equipment provided for such a mining machine includes a support arm extension 17. As illustrated in the embodiment shown in FIG. 3, for example, the drum-cutter loader 1 has been modified to provide the support arm 5 where a length suitable for use in thicker mine seams and to additionally provide that the support arm extension which is mounted on the machine body of the drum-cutter loader 1 for pivotal movement about a pivot axis defined by pivot 6. The support arm extension 17 is rigidly connected by bolts 22 to the support arm 5, and at the goaf side the arm is rigidly connected to lug 23 of the drive motor 9. This arrangement forms with the support arm 5 a component which can pivot about the pivot axis formed by pivot 6 and by which the operation of piston and cylinder assembly 8 acts on the support arm extension 17 connecting the rod end of the piston and cylinder assembly 8 to the support arm extension 17 as shown in FIG. 3. In this embodiment, the auxiliary cutting drum 12 situated above the longwall conveyor 2 is underneath the swivel axis 6, and hence in the area in which pivotal movement causes no significant variations to the position of the auxiliary cutting drum above the conveyor.
When increasing the cutting range of cutting drum 3 through the use of support arm extension 17, a corresponding increase in the length of shoulder 7 and jib 13 is required. Cutting drum 3 may be positioned at any of many vertical heights, including cutting heights identified by dot-dash lines A and B in FIG. 3. The allowable pivotal pivot range of support arm 5 is denoted by "X" in the Figure. The auxiliary cutting drum 12 is concurrently positioned at different location each time in which the cutting drum 3 is repositioned. In the illustration of FIG. 3, the auxiliary cutting drum 12 is positioned at locations indicated by circles of dot-and-dash lines A, and B, when cutting drum 3 is positioned at locations indicated by reference numeral A and B, respectively. In the embodiment of the present invention shown in FIG. 5, a support arm 5 is illustrated without a cutting drum and machine body which carries the arm. The drive motor 9 for the cutting drum is situated in a special protective housing 24. The housing is fastened to the sidewall of the support arm which is turned away from the coal face. The housing is provided with a radially projecting shoulder or housing extension 25 which rotatably supports one end of the auxiliary cutting drum 12. The jib 13 rotatably supports the other end of the auxiliary cutting drum by way of shaft 15 of the drum. The jib 13 is connected to a protective cover 26 forming a seal for the housing 24 and thereby forms a common structural unit. A train of gears 27, 29 is arranged in the housing extension 25 to drivingly interconnect the drive pinion 28 of dive motor 9 with drive shaft 15 of the auxiliary cutting drum.
While the present invention has been described in accordance with the preferred embodiments of the various figures, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiment for performing the same functions of the present invention without deviating therefrom. Therefore, the present invention should not be limited to any single embodiment but rather construed in breadth and scope in accordance with the recitation of the appended claims.
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A drum cutter mining machine translatable along a longwall conveyor includes an auxiliary cutting drum for breaking up pieces of mineral carried by the longwall conveyor system. The auxiliary cutting drum is supported by a jib and an arm extension affixed in a fixed relationship with a support arm. The auxiliary cutting drum is positioned by the same actuator which pivotally positions the drum-cutter cutting drum at a desired cutting height at the mine roof and other times at the floor. Positioning of the cutting drum at the desired cutting height automatically positioned the auxiliary cutting drum.
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BACKGROUND OF THE INVENTION
The present invention relates to crystal oscillators with frequency regulation as a function of the temperature. These oscillators essentially comprise an amplifier, whose output is connected to the input across a circuit incorporating an oscillating piezoelectric crystal, the gain of the system with the thus formed feedback loop being higher than unity in order to satisfy auto-oscillation conditions. The frequency regulation as a function of temperature is obtained by connecting in series with the crystal a capacitor of appropriate value, whose capacitance varies as a function of a voltage applied to its foils and by creating said voltage, normally called the "compensating signal" in a compensating circuit incorporating a heat-sensitive element.
However, the known compensating circuits do not make it possible to industrially obtain a complete frequency regulation in the case where the oscillating crystal has been cut with a particular section, which is advantageous in certain respects and is known under the name AT. Thus, for this section, the thermal drift of the frequency of the crystal affects the shape of a third degree algebraic curve.
In the latter case, it is consequently necessary to create a compensating signal which also varies in accordance with a function of the third degree. This leads to known compensating circuits which are difficult and expensive to produce as a result of the high precision and stability required by the compensating signal to be obtained and the special characteristics required of certain components, such as heat-sensitive elements or thermistors.
In the French Patent of the present Applicant Company filed under No. 74/30338 and published under No. 2,284,219 and equivalent to U.S. Pat. No. 4,020,426 it is proposed to subdivide the curve corresponding to the third degree variation law of the compensating signal into three arcs and to ensure the formation thereof by three separate circuits each having a heat-sensitive element.
For this purpose, in the said crystal oscillator constituted by an oscillating circuit in the form of a feedback loop and incorporating an amplifier, an oscillating piezoelectric crystal and an element having a reactance which is variable as a function of electrical signals or quantities, the electrical compensating signal or quantity is created by a circuit having two terminals, one kept operating at a fixed potential by a dividing bridge and the other raised to a potential variable as a function of the temperature. First and second heat-sensitive elements are connected then by one of their ends to said other terminal, their other end being respectively connected to two dividing bridges, whereof one comprises a third of said elements, the three points being connected to the terminals of the said power supply.
Thus, at around 30 MHz, this prior art oscillator supplies a frequency stability as a function of the temperature of approximately 10 -6 in the temperature range of -40° to +80° C.
However, for certain uses such as avionics, the temperature ranges to be covered are even wider and are typically between -55° and +105° C. The temperature compensating circuit of the aforementioned prior art does not satisfy such a requirement. The correction voltage curve supplied by said circuit as a function of the temperature has two inflection points with a direction change of the curvature, respectively on either side of the limit temperature (-40° to +80° C.).
A partial solution can be envisaged, such as an increase in the supply voltage of the circuit but has the disadvantage of increasing the potential at the terminals of the capacitor which is variable as a function of the voltage, i.e. the sensitivity thereof is reduced. Moreover, beyond 70° C., the thermistors have a too limited resistance variation as a function of the temperature.
BEST SUMMARY OF THE INVENTION
The oscillator according to the present invention does not have these disadvantages. Thus, instead of the fixed value dividing bridge of the aforementioned patent specification applying in operation a fixed potential to one of the terminals of the compensating circuit, it uses a dividing bridge whose value varies as a function of the temperature and incorporating thermistors in addition to resistors. Thus, a variable potential is applied to said terminal forming a complementary compensating voltage. This complementary compensating circuit more paticularly acts at the ends of the temperature range and does not significantly change the compensating voltage variation law in the median range of frequencies.
According to a particularly advantageous constructional variant, the complementary compensating circuit is structurally constituted by the same elements as the compensating circuit of the aforementioned prior art, said second circuit being reversed in its connecting terminals to the power supply. This variant leads to an improvement in the compensating voltage variation curve for the median range of frequencies.
The invention more specifically relates to a crystal oscillator with frequency regulation in a wide range of temperatures with an oscillating circuit in the form of a feedback loop comprising an amplifier, an oscillating piezoelectric crystal and a capacitor variable as a function of the voltage and a two-part compensating circuit connected to the terminals of a d.c. supply, each part having elements whose electrical resistance is dependent on the temperature, said circuit supplying at its terminals a compensating signal applied to the variable capacitor, one of the terminals being raised to a main compensating potential by a main part of the circuit constituted by first and second said elements connected by one of their ends to said terminal, their other end being respectively connected to two dividing bridges, whereof one incorporates a third of said elements, the two bridges being connected to the terminals of the power supply, wherein the other of the terminals is arranged to a complementary compensating potential by the other part of the compensating circuit, said compensating signal resulting from the difference between the main and complementary potentials.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in greater detail hereinafter relative to non-limitative embodiments and with reference to the attached drawings, wherein show:
FIG. 1 a diagrammatic view of the prior art compensating circuit.
FIG. 2 the variation curve of the compensating voltage as a function of temperature supplied by the circuit of FIG. 1.
FIG. 3 a partial diagrammatic view of the complementary compensating circuit according to the invention.
FIGS. 4A and 4B two explanatory diagrams corresponding to the two aforementioned cases.
FIGS. 5A and 5B two explanatory diagrams corresponding to the two aforementioned cases.
FIGS. 6A, 6B and 6C three diagrams with FIG. 6C showing the variation curves of the final compensating voltage compared with the main and complementary compensating curves FIGS. 6A and 6B.
FIG. 7 a variant of the compensating circuit according to the invention having two reversed circuits.
FIG. 8 in rectangular axes, the voltage curves supplied by the complementary compensating circuit.
FIG. 9 in rectangular axes, the total compensating voltage curve resulting from the difference between the main and complementary compensating voltages.
FIG. 10 another embodiment of the compensation circuit according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a diagrammatic view of the compensating circuit according to the prior art. The oscillator is constituted in per se known manner by a feedback loop incorporating a piezoelectric crystal 1, an amplifier 2 and two capacitors C 1 and C V which, with the crystal, determine the oscillating frequency. One of the capacitors C V is of the type known under the varicap and its value varies in accordance with the value of a d.c. voltage applied to its terminals shown at 7' and 8'. The control voltages of this capacitor are created at its terminals by the outputs 7 and 8 of the compensating circuit, whose output 8 supplies a voltage e 8 variable as a function of the temperature. The voltage e 7 of output 7 is at constant value and is produced by the dividing bridge 10 bounded by dashes.
The potential difference (e 8 -e 7 ) between outputs 8 and 7 modifies the capacitance value of the varactor-type capacitor and consequently, appropriate values of the compensating circuit elements, can compensate variations in the frequency supplied by the crystal oscillator as a function of temperature.
FIG. 2 shows in a diagram in rectangular axes the variation curve of the compensating voltage as a function of the temperature supplied by the prior art circuit of FIG. 1.
In this curve, the temperatures are plotted on the abscissa and the compensating voltages on the ordinate and towards the two ends of the temperature range the curve has two inflexion points P1 and P2 on either side of which it is no longer possible to obtain the compensation. The necessary curve arcs A 1 ,A 2 are replaced by curve arcs B 1 ,B 2 .
Thus, in the prior art, the temperature range is limited to that defined by the inflexion points and in practice these limits are -40° to +80° C.
FIG. 3 shows in a partial diagrammatic view the complementary compensating circuit according to the invention. This circuit which takes the place of the dividing bridge bounded in dashes 10 in FIG. 1 serves to create a voltage e 7 , which varies as a function of the temperature in accordance with a variation law such that the compensating voltage e=e 8 -e 7 applied to the varactor-type capacitor has its inflexion points P 1 , P 2 for much more widely varying temperature values than in the prior art.
As compared with the dividing bridge R 12 R 13 in FIG. 1, the circuit has two thermistors RT 4 and RT 5 in series in the branch of R 13 connected to the negative terminal of the power supply, one of the two thermistors RT 5 being shunted by a resistor R 14 . The operation of such a complementary compensating circuit is apparent from FIGS. 4 and 5.
FIGS. 4A and 4B illustrate the operation at low and high temperatures.
At low temperatures, the value of thermistor RT 5 is very high compared with that of resistor R 14 . Thus, the circuit can be represented as in FIG. 4A where blocks 12 and 13 represent resistive elements which do not vary as a function of temperature.
At the limits with RT 4 approaches infinity e 7 assumes a value close to V A , whilst for RT 4 zero e 7 =V A ×R 13 /(R 12 +R 13 ).
This variation of e 7 is given in FIG. 5A in the curve in rectangular marked I. At high temperatures, the value of thermistor RT 4 is negligible compared with that of the other elements of the circuit. Thus, the circuit can be represented as in FIG. 4B where the blocks 12 and 15 represent the resistive elements which do not vary as a function of the temperature.
As hereinbefore, the limit values for RT 5 , respectively infinity and zero give the variation limits of voltage e 7 . This variation of e 7 is given in FIG. 5B on the curve in rectangular axes marked II.
FIGS. 6A, 6B and 6C show in rectangular axes, the variations of the final compensating voltage in FIG. 6C by comparison with the curves in FIGS. 6A and 6B for the main and complementary compensation respectively.
FIG. 6A is identical to that of FIG. 2 which is of the compensating voltage e 8 supplied by the circuit of the prior art while FIG. 6B is that of the compensating voltage e 7 supplied by the complementary compensating circuit of FIG. 3. This curve comprises the extreme arcs described hereinbefore located on either side of the central part where the circuit of FIG. 3 has little influence. Its only influence is indicated by the slope of the curve of FIG. 6A in the sense of reductions towards high temperatures.
FIG. 6C shows the final compensating voltage (e 8 -e 7 ) applied to the varactor-type capacitor of the oscillator. Voltage e is represented graphically, to within a constant length, by the length of segment GH determined on a vertical line by the intersection with the curves of FIGS. 6A and 6B. It can be seen that the curve of FIG. 6C no longer has inflexion points at the end of the temperature range and that its centres of curvature there are always on the same side of the tangent. The overall compensation curve consequently satisfies the conditions indicated hereinbefore for the extension of the temperature range where compensation is ensured.
To give an idea of values, the range of temperatures where compensation is ensured then extends from -55° to +105° C. for a compensation of 10 -6 of the frequency.
FIG. 7 shows a particularly advantageous variant of the complementary compensating circuit according to the invention. The results obtained as a result of this circuit can be observed on the diagram in rectangular axes of FIG. 8.
The complementary compensating circuit of FIG. 3 creates, in the manner indicated hereinbefore a low value gradient in the medium part of the curve of the compensating voltages shown in FIG. 6, which is to be avoided in certain cases. The variant of FIG. 7 creates no gradient in this median part.
It is constituted by a complementary compensating circuit which, according to the invention, is structurally identical to the compensating circuit of the aforementioned prior art, but is reversed with regard to its connection to the power supply and the resistive voltage divider corresponding to R 1 -R 2 has been deleted. The values of the elements from which it is formed are determined in such a way that the complementary compensating voltage e 7 is only a fraction of the main compensating voltage e 8 .
FIG. 8 shows in rectangular axes the curve A of the complementary compensating voltage e 7 obtained, as a function of the temperature at the terminals of the reversed circuit of FIG. 7. It is possible to see that compared with the corresponding curve of FIG. 6B obtained with the embodiment of FIG. 3, the slope A of the curve in the median part 81 is replaced by a slightly undulating part 82, which advantageously approaches a horizontal level which is more favourable in certain cases.
FIG. 9 represents in rectangular axes the total compensating voltage variations e=e 8 -e 7 obtained in the respective cases of the prior art compensating circuit and the two compensating circuits according to the present invention. It can be seen that for the same temperature limits, namely -55° to +105° C., the variations in the voltage e to be made for the compensation are reduced much more in the case of the invention, typically 2.369 V to 4.425 V than in the prior art, typically 1.499 V to 5.662 V.
FIG. 10 shows the best example of a circuit according to the invention, giving the best results as shown in FIG. 8.
On this figure, the same device has the same number as on FIG. 7. Compared to this figure, resistors R 9 and R 19 have been deleted while resistors R 8 and R 18 have been short-circuited. Resistors R 41 and R 40 have been respectively introduced between the common connection points of R 7 , RT 3 and R 5 , RT 2 on one hand, and the common connection points of R 17 , RT 6 and RT 5 , R 15 , on the other hand.
With the circuit represented on this figure, we have obtained better results than in the case of FIG. 7, in order to stabilize the frequency of oscillations within a wide range of temperature.
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A frequency regulated crystal oscillator with (1) an oscillating circuit made up of an amplifier, piezoelectric crystal and voltage controls capacitor, and (2) a two-part compensating circuit connected to the terminals of the variable capacitor, each part having thermistors whose resistance varies with temperature to produce complementary signals and which are shunted with electrical resistors.
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FIELD OF INVENTION
[0001] The present invention relates to a device for singularising coins.
BACKGROUND INFORMATION
[0002] In recent times, payment machines have been increasingly used for cashing in monies for purchased goods, which e.g. are placed at the tills of supermarkets or likewise, and into which the owed sum is added in the form of coins. The coins thereby, are filled into a receiver- or collection container in an uncontrolled and unsorted manner, whereupon they must be singularised and led to a coin tester. Thereby, the singularisation must be so reliable that a reliable transfer of only one coin is ensured, even with great differences in size and thickness.
[0003] A singularisation device for coin sorting- and/or coin counting machines is known from DE 40 09 087 A1, with which a hole disk rotatable on a base plate is arranged behind a receiver shell, wherein the coins are transported in the holes of the hole disk. Thereby, the base plate and the hole disk are arranged in an oblique manner. The holes of the hole disk in each case have the same diameter, and specifically such a diameter, which is slightly larger that that of the largest coin type to be processed. The thickness of the hole disk is generally such that the thicker coins of the hole disk slightly project beyond this. The counter plate at a certain height, merges into a recessed abutment surface, onto which the coins transported via the holes of the hole disk fall or slide, and are transported away by a conveyor member. A leaf spring is arranged in the upper region of this device in front of the hole disk, and this spring which lies directly opposite the hole disk, and inasmuch as this is concerned, acts as a deflector, thus coins which have not been singularised in a correct manner and project too far beyond the front side of the hole disk are displaced away.
SUMMARY OF INVENTION
[0004] The present invention relates to a device for singularising coins, which is simple in its construction, reliably ensures the singularisation with little design effort, and is inexpensive in manufacture.
[0005] By way of the fact that a flap is arranged in an obliquely inclined base plate, over which a catch element is provided for catching coins, said flap opening synchronously with the driven catch element for leading the caught elements further, one provides means by way of which a reliable singularisation of coins is possible.
[0006] The catch element is advantageously designed as a rotor with a hub and at least one blade, wherein the rotor rummages through the coins lying in a collection container in front of the base plate in a random manner, and catches the coins. By way of rummaging through the heap of coins by way of the rotor, the filling condition in the container is oblique, by which means coins falling down on rotation have space. The accommodation capacity may be increased in this manner.
[0007] A simple and thus inexpensive synchronisation of the flap with the catch element is achieved in that at least one projecting cam is arranged on the catch element, and this cam cooperates with a cam surface provided on the flap for the synchronous opening between the catch element and the flap.
[0008] It is advantageous for the rotor with the hub and at least one blade to be provided in the region of the hub with freeings for the coins to slide away. In this manner, surplus coins which are caught by the blade, fall back into the heap of coins without any disturbance.
[0009] It is particularly advantageous for an electrical control for the electric motor driving the catch element to be provided, which briefly stops the catch element in a position assigned to the flap, and then travels further or carries out one or more reversals in rotational direction between stoppage and continued travel, by which means a shaking or vibration of the catch element arises, since excess caught coins are shaken off or obtain an impulse, that causes them to fall back into the coin heap by way of this movement of the catch element.
[0010] It is advantageous for the flap, transversely to the rotational direction and, as the case may be, also to the counter rotational direction of the catch element, to be provided in each case with a ramp-like prominence, since on account of this measure, on the one hand again excess coins fall away downwards, and on the other hand the coins to be singularised are led cleanly into the opening slot between the flap and the base plate.
[0011] Finally, it is advantageous for the catch elements, in particular the rotor with blade(s), to comprises prominences or thickenings on its outer periphery, by which means, in particular with a few coins which are now present in the collection container, one prevents a dipping away, as the case may be, with edgewise coins, so that the last coin present in the collection container is also caught.
BRIEF DESCRIPTION OF DRAWINGS
[0012] One embodiment example of the invention is represented in the drawing and is explained in more detail by way of the subsequent description. There are shown in:
[0013] FIG. 1 shows a perspective view of one embodiment example of the device according to the present invention, for singularising coins, without a collection container,
[0014] FIG. 2 shows a section through the device according to the present invention, according to FIG. 1 , with a collection container top,
[0015] FIG. 3 shows a perspective view of the device according to the invention, with a collection container top,
[0016] FIG. 4 shows a perspective view of the rotor from above and below and
[0017] FIG. 5 shows a perspective view of the flap mounted in the base plate of the device according to the invention.
DETAILED DESCRIPTION
[0018] The device according to the present invention represented in the FIGS. 1 to 3 comprises a housing 1 with a housing box 2 which is open at the bottom, a base plate 3 which is arranged obliquely on the housing box 2 and which is connected to the box 2 by way of locking- and/or snap connections 4 , and a collection container top 5 which is connected to the base plate 3 and/or the housing box 2 likewise via locking- and/or snap connections. The collection container top has a deflection element 6 partly covering the opening. A slot 7 is incorporated in the box 2 which serves for the insertion of the coins.
[0019] The base plate 3 according to FIG. 1 and FIG. 2 is provided with a perpendicularly standing, annular peripheral wall 8 , to which the collection container top 5 connects. Coins which have been inserted through the opening through the top 5 and deflected by the deflection element 6 , are collected as a heap of coins in an irregular manner within the limitation by the collection container top 5 and the region in the base plate 3 which lies within the peripheral wall 8 .
[0020] A circular opening with an oblique edge is provided in the base plate, in which a catch element designed as a rotor 9 is rotatable mounted. The rotor is firmly connected to the drive shaft of a gear motor 10 , and on rotation, slides on the oblique edge region of the base plate 3 . The rotor 9 comprises two curves blades 11 which are opposite one another, and which are attached onto a hub 12 . The rotor is shown in more detail from above and below in FIG. 4 . The hub 12 is closed to the top, i.e. in the direction of the collection container top 5 , and at the opposite side comprises a lug 13 for receiving the motor shaft. The rotor 9 preferably consists of plastic, wherein the housing 1 too, i.e. the housing box, the collection container top 5 and the base plate 3 consist of plastic. The blades 11 which together form an S-shape, are provided at their ends with upwardly projecting lugs 14 which serve for ploughing through the coin heap present in the collection container 5 . As may be recognised from FIG. 4 , the hub 12 between the wings at least partly comprises freeings 15 , i.e. in this region 15 the hub projects beyond the base plate 3 to a very small extent at the most. As may be recognised in FIG. 4 at the top, the hub at its side facing the d-c motor 10 comprises two lug-like cams 16 whose manner of functioning will be explained further below.
[0021] In the base plate 3 , in the upper region of this between the peripheral wall 8 and the opening for the hub 12 , a recess 17 is provided shortly next to the upper apexes of the base plate 3 , into which a flap 18 engages, which is represented in more detail in FIG. 5 . The flap 18 is rotatably mounted on the base plate 3 and/or a motor fastening arrangement 19 which is connected to the base plate via pivot lugs 20 . The surface of the flap which projects essentially out of the base plate 3 , comprises two ramp-like regions 21 , 22 which rise obliquely in the rotational direction of the rotor 9 and in its counter-direction. Furthermore, the remaining surface is slightly curved, and specifically towards the edge which displays a step 23 . The step 23 engages below the base plate 3 in a manner such that a continuous transition between the surface of the flap 18 and the surface of the base plate is present. A lug 24 is integrally formed laterally on the flap 18 , and forms a cam surface which cooperates with the cam 16 attached onto the rotor 9 , for opening the flap 18 . As may now be recognised, an eye 25 is integrally formed at the rear end of the flap 18 , into which the end of a return spring which is not shown, may engage, which after opening the flap 18 pulls this into the closure position. A path setter 26 which sets at least one fixed position of the rotor, is seated on the lug 13 of the rotor. This path setter is scanned by a sensor 27 which may be designed as an optical sensor, a Hall sensor given a metallic path setter 26 , or as any other sensor. This sensor is connected to a control which is not shown, which controls the gear motor 10 for the drive of the rotor 9 .
[0022] The control is characterised in that on starting the motor, the rotor 9 assumes a predefined starting position. This usefully lies shortly behind the flap 12 , so that a coin may be transported already with the first half rotation of the rotor. For this, the predefined position is travelled to on stopping and switching off the rotor 9 , wherein this predefined position is delivered depending on the signal of the sensor 7 in combination with the path setter 26 , which may for example be designed as a toothed disk or segment disk. Usually, the predefined position as a starting position is searched and found by way of rotating the rotor 9 backwards after stoppage of the device.
[0023] An essential feature of the invention lies in the fact that the rotor briefly stops in a position in front of the flap with each revolution, and starts and stops again, and in each case carries out a direction reversal with a small amplitude once or several times, so that the rotor carries out a vibration- or shaking procedure shortly in front of the flap. Coins which are pulled along, on or in the region of the blades or wings 11 , but do not lie in an ordered position to the flap 18 , obtain one or more impulses by way of this shaking- or vibration procedure or only by way of a brief stoppage, by which means the coins are swiped away or flung away, and fall back onto the coin heap again.
[0024] The manner of functioning of the device is as follows: The device is switched on via an external signal, e.g. via a switch-on sensor which is arranged on the collection container top, wherein the rotor 9 is travelled into the start position which lies shortly behind the flap, after the preceding singularisation procedure. The rotor or the blades 11 of this rotor travels through the heap of coins, which is located in the lower region of the base plate 3 and of the collection container top 5 , and catches one or more coins. In a position in front of the flap 18 , the control controls the gear motor 10 to perform the shaking or vibration procedure, by which means the wing 11 is moved to and fro in a short manner, so that coins which are not held cleanly in the curvature of the blade are flung away. The rotor moves further in the direction of the flap and with its cam 16 which slides along the cam surface 24 of the flap 18 , opens the flap 18 which dips downwards with respect to the base plate 3 . The coin present in the curvature of the blade is pushed over the ramp-like region of the flap and then along the surface tilts into the slot-like opening between the flap and the base plate 3 . When the rotor runs further over the flap, the cam 16 releases from the cam surface 24 and the flap is pulled closed, on account of the restoring spring which is not shown, and the procedure begins from afresh. In this manner, each coin of the coin heap is singularised, and even if the last coins are set edgewise with respect to the base plate, they are caught by the lugs 14 at the ends of the blades 11 , so that the collection container is emptied down to the last coin. If the device is switched off, then the blade 11 or the rotor 9 continues to be rotated with the help of the path setter 26 and the sensor 27 , until the start position is obtained. If the rotor on starting is not located in the start position, the position is searched in backward motion on switching on, in order not to produce an uncontrolled ejection of the coins. The shaking position is determined depending on the starting position, and the shaking is triggered by time-controlled movements.
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A device for singularising coins of different sizes and thickness with a housing which comprises an obliquely inclined base plate is suggested. A catch element for catching and conveying coins to a further processing is rotatably arranged above the base plate. The coins are randomly present at least in the lower region of the base plate on which a collection container is fastened. A flap is arranged in the base plate, which opens and closes synchronously with the driven coin catch element for leading a caught coin further.
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FIELD OF THE INVENTION
The present invention relates to a method and apparatus for temporarily attaching a rope to a vertical support, such as a tree, where the required elevation for the rope to be anchored above ground level exceeds one's reach.
BACKGROUND OF THE INVENTION
It is common practice for campers to temporarily anchor tarpaulins and such to trees and other free standing vertical supports using ropes. Presently the procedures used to anchor and remove these ropes above one's maximum reach are to either stand on another person's shoulders, or park a vehicle next to the tree and stand on top of the vehicle. Procedures such as these are quite hazardous. A person could slip and fall off the vehicle or from the shoulders of the person supporting them.
SUMMARY OF THE INVENTION
What is required is a method of securing a rope to a tree, at a height that exceeds ones reach, which can be effected from ground level.
According to one aspect of the present invention there is provided a method for temporarily attaching a rope to a vertical support, such as a tree. In order to attempt the described method there first must be provided a rope and a rope attachment kit which includes a yoke, a first pole and a second pole. The yoke includes an elongate body having a first end and a second end. Means for engaging a rope project radially from the elongate body. The rope engaging means are spaced from the first end. Means for interlocking with a pole are positioned at the second end of the elongate body. Means for receiving a hook depend from the elongate body. The first pole has a first end and a second end. The first end has interlocking means compatible with the interlocking means at the second end of the elongate body of the yoke. The second pole has a first end and a second end. The first end has rope engaging means. It is preferred that one of the first pole and second pole also have a hook at the second end.
The rope and the rope attachment kit are used to attach the rope to a vertical support, such as a tree, according to the following method steps. Firstly, tying a first loop at an end of the rope and positioning the rope as a second loop around a vertical support. Secondly, forming a third loop and extending the third loop into the first loop. Thirdly, extending a first end of the yoke into the third loop until the rope is engaged by the rope engaging means. Fourthly, drawing the third loop tight to capture the first end of the yoke and coupling the interlocking means of the first pole with the interlocking means of the pole mounted apparatus. Fifthly, engaging the rope with the rope engaging means of the second pole, and using the second pole to lift the rope to a desired height on the vertical support while concurrently using the first pole to lift the pole mounted yoke to said desired height. Sixthly, drawing the second loop tight and removing the second pole and the first pole, thereby leaving the rope held by the yoke to the vertical support.
With the method, as described above, a rope may be positioned at a desired height on a tree while standing at ground level. Utilizing the pole mounted yoke and two poles, the rope may be raised five to six feet above one's outstretched arms while comfortably standing on the ground with neither strain nor hazard. When the rope is subsequently to be taken down it is possible to knock the yoke out of position by hitting it with a stick. Even more beneficial results may be obtained, however, when the step of removing the rope from the tree involves catching the hook receiving means on the yoke with the hook at the second end of one of the first pole and the second pole and using the hook to pull the yoke out of the third loop.
According to another aspect of the present invention there is provided the kit, as described above.
According to yet another aspect of the present invention there is provided the key component of the kit, that being the yoke.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings, wherein:
FIG. 1 is a perspective view illustrating a first step of a method of temporarily attaching a rope to a vertical support.
FIG. 2 is a perspective view illustrating a second step of a method of temporarily attaching a rope to a vertical support.
FIG. 3 is a perspective view illustrating a third step of a method of temporarily attaching a rope to a vertical support.
FIG. 4 is a perspective view illustrating a fourth step of a method of temporarily attaching a rope to a vertical support.
FIG. 5 is a perspective view illustrating a fifth step of a method of temporarily attaching a rope to a vertical support.
FIG. 6 is a perspective view illustrating a sixth step of a method of temporarily attaching a rope to a vertical support.
FIG. 7 is a perspective view illustrating a rope temporarily attached to a vertical support in accordance to the teachings of the present invention.
FIG. 8 is a perspective view illustrating a method of removing the rope illustrated in FIG. 7.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment, a kit for temporarily attaching a rope to a vertical support will now be described with reference to FIGS. 1 through 8.
The kit includes a pole mounted yoke 10, a first pole 12 and a second pole 14. Referring to FIGS. 3 through 8, yoke 10 has an elongate cylindrical body 16 with a first end 18 and a second end 20. Two radially projecting arms 22 and 24 are spaced from first end 18. Radially projecting arms 22 and 24 serve as means for engaging a rope, as will hereinafter be further described. A female coupling 26 is positioned at second end 20. Female coupling 26 serves as means for interlocking with first pole 12, as will hereinafter be further described. A cord loop 28 extends through a transverse passage 30 in body 16. Loop 28 is of such a length that it depends from body 16, to serve as a hook receiving means as will hereinafter be further described. First pole 12 has a first end 32 and a second end 34. First end 32 has a male coupling 36 that is capable of mating with female coupling 26 at second end 20 of body 16 of yoke 10. Second pole 14 has a first end 38 and a second end 40. First end 38 has a transverse slot 42 which serves as rope engaging means as will hereinafter be further described. One of first pole 12 and second pole 14 has a hook 44 at second end 34 and 40, respectively. In the illustrated embodiment second end 40 of second pole 14 is illustrated as having hook 44.
Using a rope 46 and the rope attachment kit described above, rope 46 may be temporarily attached to a vertical support 48, such as a tree, according to the following method steps. Firstly, tying a knot 50 to form a first loop 52 at an end 54 of rope 46 and positioning rope 46 as a second loop 56 around vertical support 48, as illustrated in FIG. 1. Secondly, forming a third loop 58 and extending third loop 58 into first loop 52, as illustrated in FIG. 2. Thirdly, extending first end 18 of yoke 10 into third loop 58 until rope 46 is engaged by arms 22 and 24, as illustrated in FIG. 3. Fourthly, drawing third loop 58 tight to capture first end 18 of yoke 10 and coupling male coupling 36 of first pole 12 with female coupling 26 of yoke 10, as illustrated in FIG. 4. Fifthly, engaging rope 46 in transverse slot 42 of second pole 14, and using second pole 14 to lift rope 46 to a desired height on vertical support 48 while concurrently using first pole 12 to lift yoke 10 to said desired height, as illustrated in FIG. 5. Sixthly, drawing second loop 56 tight and removing second pole 14 and first pole 12, thereby leaving rope 46 secured solely by yoke 10 to vertical support 48, as illustrated in FIGS. 6 and 7. By following the method steps described, rope 46 can be secured to vertical support 48, (typically, a tree) in a campground at a height of 5 or 6 feet above one's reach while standing at ground level. When it is time to leave the campground and rope 46 is to be removed, this is accomplished by catching loop 28 which depends from yoke 10 with hook 44, and using hook 44 to pull yoke 10 out of third loop 58, as illustrated in FIG. 8.
Although the present invention was initially developed for the purpose of temporarily anchoring tarpaulins to trees, there are numerous other uses. Over the course of a season, the knots holding a hammock in place become impossible to untie. This problem can be avoided by securing the hammock in place with the present invention. When felling a tree, it is important to control the direction in which the tree falls. This can be accomplished by securing a line to the tree in accordance with the teachings of the present invention. Experienced campers do not keep food in their tents, as the food tends to attract bears and other animals. As a safety measure, food is suspended in a tree at a reasonable distance from the tents. The present invention can be used to suspend the food. Once a hunter has killed a deer or moose, he generally takes steps to suspend the carcass. The present invention can be used to suspend the carcass in preparation for preliminary butchering.
Once weight has been placed upon yoke 10, it becomes very difficult to knock yoke 10 out of position. The greater the weight applied to yoke 10, the more important it becomes to be able to apply a force to pull yoke 10 out of position. Although this could be accomplished by re-engaging male coupling 36 on pole 12 with female coupling 26 on yoke 10, the use of hook 44 is preferred for a number of reasons. It is difficult to re-engage male coupling 36 with female coupling 26 from ground level. A pulling force can place a strain upon the threaded engagement between male coupling 36 and female coupling 26.
It will be apparent to one skilled in the art that modifications may be made to the illustrated embodiment without departing from the spirit and scope of the invention as hereinafter defined in the Claims.
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This is a method and apparatus for temporarily securing ropes to trees or other free standing vertical supports, eliminating the need to climb or use a ladder. The method uses a pole mounted yoke in conjunction with two poles. From ground level one can easily secure a rope six feet or more above one's reach. The only height limit is the length of the poles that are used.
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The United States Government has rights in this invention pursuant to Contract No. W-7405-ENG-48 between the United States Department of Energy and the University of California for the operation of Lawrence Livermore National Laboratory.
RELATED APPLICATION
This application is a continuation-in-part of U.S. application Ser. No. 08/264,261, files Jun. 23, 1994, entitled "Star Cell Type Core Configuration For Structural Sandwich Materials", now U.S. Pat. No. 5,437,903 issued Aug. 1, 1995, and assigned to the same assignee.
BACKGROUND OF THE INVENTION
The present invention relates to the fabrication of sandwich type structural materials, particularly to the fabrication of light weight core material of the sandwich type, and more particularly to a method for fabricating a core material pattern which utilizes star shaped cells.
Sandwich constructions involve a light weight core material that supports the faces and transfers load between them. The sandwich constructions generally utilize low density core materials. The elastic mechanical behavior for low density materials allows for deformation due to the flexibility of the core material when utilized in sandwich type constructions.
The traditional core material is of a triangular cell pattern, and more recently of a honeycomb (hexagonal) cell pattern. However, the triangular or hexagonal cell patterns of core materials do not easily conform to curved shapes needed to fabricate curved sandwich material panels. Thus, there has been a need for a core material which supports the faces of the sandwich construction materials on transfer loads between the faces, while being sufficiently flexible so as to conform easily to curved shapes. That need has been satisfied by the invention described and claimed in above-identified U.S. Pat. No. 5,437,903, which involves an improved microstructure for light weight core material utilizing a star/hexagonal pattern which allows easy conformation to curved shapes.
Various fabrication processes have been developed for the cellular sandwich structural materials, in an effort to produce these materials at a reasonable cost. For example, the prior honeycomb (hexagonal) material is fabricated by first vertically stacking a series of flat sheets with bonds located at the points of interconnection between the hexagonal cells, honeycomb configuration. The present invention, involving a method for fabricating an improved microstructure for light weight core material using the star containing pattern of the above-identified patent, utilizes features of the prior known processes by bonding or welding folded or unfolded sheets of material at selected locations to interconnect the sheets in both a vertical and a horizontal direction, and then mechanically pulling the interconnected sheets normal to the plane of the sheets which expands the sheets and form the star cells.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a fabrication method for an improved micro-structure for light weight core material of sandwich constructions.
A further object of the invention is to provide a method of fabricating a core material for structural sandwich constructions which utilizes star shaped cells.
Another object of the invention is to provide a fabrication method for a new pattern for microstructures which includes star shaped cells.
Anther object of the invention is to provide a method for fabricating sandwich type materials which utilizes star shaped cells, which involves bonding flat or folded sheets of material in both vertical and horizontal directions, to form a block of sheets, whereafter the sheets are mechanically pulled normal to the plane of the sheets causing expanding and formation of the cells.
Other objects and advantages of the invention will become apparent from the following description and accompanying drawings. The invention enables a simple and cost effective method to produce the star cell containing microstructure for cellular core material used in sandwich type structural materials. The fabrication method of this invention merely involves bonding folded or unfolded sheets of low density material in both vertical and horizontal directions to form a block which when mechanically pulled normal to the plane of the sheets expands to form interconnected star shaped cells. The fabrication method of this invention produces a cellular core material that is much more flexible than prior known core materials and can be conformed easily to curved shapes, thereby providing for the fabrication of curved sandwich panels.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated into and form a part of the disclosure, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
FIG. 1 illustrates a star/hexagonal cell configuration, for use such as in sandwich type structures.
FIG. 2 is an enlarged partial cross-sectional view of a block of bonded or welded flat sheets of low density material in accordance with the fabrication method of this invention.
FIG. 3 is an enlarged partial cross-sectional view similar to FIG. 2 except the sheets of low density material are folded and bonded together to form a block, as in the FIG. 2 fabrication method.
DETAILED DESCRIPTION OF THE INVENTION
The present invention involves a fabrication method for a microstructure pattern containing star shaped cells for cellular core material, such as described and claimed in above-referenced U.S. Pat. No. 5,437,903. The microstructure star containing pattern for the sandwich core material fabricated by the present invention is illustrated in FIG. 1.
As seen in FIG. 1, the microstructure pattern is composed of a combination of six pointed star shaped cells 10 and hexagonal shaped cells 11. The star shaped cell 10 include six points 12, with each point 12 formed by interconnect members 13 and 14 positioned at a 60° angle, with member 13 of one point and member 14 of an adjacent point 12 being interconnected at 15. The hexagonal cells 11 include six interconnected members or sides 16, 17, 18, 19, 20, and 21, with members or sides 16-17 and 19-20 forming points 22 and 23, with members or sides 17 and 20 forming flat surfaces between members 16-18 and 19-21. As seen in FIG. 1, either of points 22 or 23 of the hexagonal cells 11 is positioned against interconnects 15 between points 12 of star cells 10. Note that the length of the members 13 and 14 of star cells 10 are the same length as members or sides 16-21 of hexagonal cells 11. As seen in FIG. 1, each star cell 10 is surrounded by six (6) hexagonal cells 11, with two (2) hexagonal cells 10 positioned intermediate two adjacent star cells 10, and with each of the points 12 of a star cell 10 being in contact with a point 12 of an adjacent star cell 10. The microstructure composed of star shaped cells 10 and hexagonal shaped cells 11 is positioned intermediate a pair of panel faces or members which define a sandwich type structure panel as conventionally known in the art. The number of cells within the sandwich panel will vary depending on the width of the panel and the desired density of the core material.
By way of example, with a sandwich panel having a thickness of 1/2 inch, the length of the members 13 and 14 forming the points 12 of the star cell 10 and the length of the members or sides 16-21 of the hexagonal cell 11 is 1/4 inch, and may be constructed of any material such as metals, ceramics, polymers, glasses, natural products, etc.
Referring now to the fabrication method for producing the star cell containing microstructure of FIG. 1, reference is made to FIGS. 2 and 3, wherein sheets (flat or folded) of low density material are bonded, welded, or otherwise secured together, defined hereinafter as bonding, in both vertical and horizontal directions to form a block. The thickness of the bond or weld sections are greatly exaggerated for illustration purposes. Basically, the sheets of material, either flat (FIG. 2) or folded (FIG. 3) are bonded together to form a block, only part of which as shown, whereafter the block of sheets is expanded to form a light weight star containing configuration similar to that of FIG. 1.
Referring first to FIG. 2, a partial block 30 is composed of pairs of sheets generally indicated at 31 of material constructed of aluminum, for example, with each sheet having a thickness of 0.01 mm to 10 mm, the pairs of sheets are bonded together in both a vertical and a horizontal direction. As shown, the pairs of sheets 31 are composed of vertically aligned flat sheets 32 and 33 bonded together, such as by polymeric adhesives, at each end and in the center thereof as indicated at 34, 35, 36, and are referred to hereinafter as sheet pairs. The thus bonded sheet pairs are indicated at 37, 38, 39, 40, 41, 42, and 43. The location of the center bond 35 of each sheet pair determine the length of the side members of the star shaped structure, such as members 13-14 of star cell 10. The sheet pairs 37 and 39 are bonded at 44 and 45 to sheet pair 38 and at 46 and 47 to sheet pair 40; while sheet pairs 41 and 43 are bonded at 48 and 49 to sheet pair 40 and at 50 and 51 to sheet pair 42. As indicated by bonds 52 and 53, sheet pairs 37 and 39 are bonded to adjacent sheet pairs similar to 38 and 40 not shown, but after which sheet pairs similar to sheet pairs 37 and 39 are bonded, such that the block 30 contains a series of repeated spaced sheet pairs 37-39 and 41-43, pairs 38, 40, and 42 positioned therebetween. The location of the bonds 44-51 of the adjacent pairs of sheet pairs also determines the length of the side members of star cells 10 of FIG. 1.
The block 30 as illustrated in FIG. 2 is then subjected to a mechanical pull to expand the sheet pairs with respect to one another. The sheet pairs are mechanically pulled normal to the plane of the sheets 32 and 33, which expands the sheet pairs to form the star shaped cells and interconnecting cells. This can be envisioned by pulling sheet pairs 37 and 41 and sheet pairs 39 and 43, while simultaneously pulling sheet pairs 38, 40, and 42 with corresponding sheet pairs, not shown, in opposite directions. Thus when sheet pairs 37 and 39 and sheet pairs 41 and 43 are mechanically pulled with respect to each other, the area intermediate the sheet pairs 37 and 39 or sheet pairs 41 and 43 form a pattern similar to a star shaped cell indicated at 10'; and the areas on each side of sheet pair 40 form positions of interconnecting cells indicated at 11'. The interconnecting cells 11' formed by pulling the sheets of block 30 are not hexagonal in shape. Although the appearance of the cells thus formed appear different from the explicit star pattern of FIG. 1, the thus formed microstructure will still possess the advantages of the star/hexagonal structure of FIG. 1, because the layout or block 30 of FIG. 2 conforms to the star template. Following the mechanical pulling the thus formed microstructure is bonded intermediate a pair of panel faces of members, not shown.
The fabrication method illustrated by FIG. 3 differs from that illustrated by FIG. 2 in utilizing a single folded sheet in place of the two flat sheets 32 and 33 for each of the sheet pairs 37-42 of FIG. 2 and the replacement of the end and center bonds 34, 35, and 36 of each sheet pair with two end bonds. As seen in FIG. 3 a partial block 30' is composed of pairs of sheets generally indicated at 31' of low density material constructed of aluminum and thickness of 0.01 mm to 10 mm, for example, with the pairs of sheets 31' each composed of a single folded sheet 55 with ends thereof bonded at 56 and 57 to a central section 58 of the folded sheet 55, and referred to hereinafter as sheet pairs. The bonds 56 and 57 may be composed of aluminum and produced by polymeric adhesives for example. The thus bonded sheet pairs are indicated at 37', 38', 39', 40', 41', 42', and 43'. As in the method illustrated by FIG. 2, the sheet pairs 37' and 39' are bonded at 44' and 45' to sheet pair 38' and at 46' and 47' to sheet pair 40'; while sheet pairs 41' and 43' are bonded at 48' and 49' to sheet pairs 40' and at 50' and 51' to sheet pair 42'. As indicated by bonds 52' and 53' sheet pairs 37', 39', 41' and 43' may be bonded to adjacent sheet pairs sheet pairs 38', 40', and 42' interposed therebetween, as described above. As pointed out above, the location of the end bonds 56 and 57 and bonds 44-51 determine the length of the side members of the star cell and the interconnecting cells, such as the hexagonal cells of FIG. 1. As set forth above with respect to the method illustrated by FIG. 2, the block 30' of FIG. 3, which when mechanically pulled normal to the plane of the sheets, expands to form star shaped cells 10' and interconnecting cells 11'. After expansion, the microstructure is bonded intermediate a pair of panel faces or members not shown to define a sandwich structure.
It has thus been shown that the present invention provides a method for fabricating structural sandwich material utilizing star shaped cells. This method is carried out using either flat sheets or folded sheets bonded to form a star configuration when mechanically expanded, and thereafter positioned between panels or members to form a completed sandwich type structural material. Although the appearance of the cell forms could look quite different from the explicit six-point star pattern, the material will still possess the advantages of this configuration because the manufacturing layout conforms to the star pattern.
While particular sequences of operations, materials, parameters, and structural configurations, etc., have been set forth to exemplify and explain the principles of the invention, such are not intended to be limiting. Modifications and changes may become apparent to those skilled in the art, and it is intended that the invention be limited only by the scope of the appended claims.
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A method for fabricating structural sandwich materials having a core pattern which utilizes star and non-star shaped cells. The sheets of material are bonded together or a single folded sheet is used, and bonded or welded at specific locations, into a flat configuration, and are then mechanically pulled or expanded normal to the plane of the sheets which expand to form the cells. This method can be utilized to fabricate other geometric cell arrangements than the star/non-star shaped cells. Four sheets of material (either a pair of bonded sheets or a single folded sheet) are bonded so as to define an area therebetween, which forms the star shaped cell when expanded.
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CLAIM OF PRIORITY
[0001] The present application claims priority from Japanese patent application JP 2007-244645 filed on Sep. 21, 2007, the content of which is hereby incorporated by reference into this application.
FIELD OF THE INVENTION
[0002] The present invention relates to a plasma display panel (hereinafter also referred to as a plasma panel or a PDP), and in particular to a plasma display device including a plasma panel structure capable of reducing an address discharge timelag and deterioration thereof to realize a PDP with high image quality, and a drive device thereof.
BACKGROUND OF THE INVENTION
[0003] In recent years, plasma display devices have become hopeful as color display devices with large screens and low-profile. In particular, alternating-current (AC) coplanar-discharge type PDP, which generates the display discharge between electrodes disposed on the same substrate, and is driven in an alternating-current manner, is the type most advanced in practical applications because of simplicity in structure and high reliability. Hereinafter, a specific example of the ac coplanar-discharge type PDP in the related art will be explained.
[0004] FIG. 2 is an exploded perspective view illustrating a part of a structure of a typical ac coplanar-discharge type PDP by way of example. The PDP shown in FIG. 1 has a front panel 21 and a rear panel 28 which are made of glass and affixed together in an integrated manner. The present example is a reflection type PDP in which phosphor layers 32 of red (R)-, green (G)-, and blue (B)-color phosphors are formed on the rear panel 28 . The front panel 21 has pairs of sustaining discharge electrodes (sometimes referred to as “display electrodes”) arranged in parallel with each other with a specified spacing therebetween on its surface facing the rear panel 28 . Each of the pairs of sustaining discharge electrodes is composed of one of common transparent electrodes (hereinafter referred to merely as X electrodes) ( 22 - 1 , 22 - 2 , . . . ) and one of independent transparent electrodes (hereinafter referred to merely as Y electrodes or scanning electrodes) ( 23 - 1 , 23 - 2 , . . . ). Further, for the purpose of supplementing the electric conductivity of the transparent electrodes, the X electrodes ( 22 - 1 , 22 - 2 , . . . ) and the Y electrodes ( 23 - 1 , 23 - 2 , . . . ) are overlaid with opaque X bus electrodes ( 24 - 1 , 24 - 2 , . . . ) and opaque Y bus electrodes ( 25 - 1 , 25 - 2 , . . . ) extending in a direction of an arrow D 2 indicated in FIG. 2 , respectively. Further, for the ac driving, the X electrodes ( 22 - 1 , 22 - 2 , . . . ), Y electrodes ( 23 - 1 , 23 - 2 , . . . ), X bus electrodes ( 24 - 1 , 24 - 2 , . . . ), and Y bus electrodes ( 25 - 1 , 25 - 2 ,. . . ) are insulated from the discharge. More specifically, each of these electrodes is covered with a dielectric layer 26 typically formed of a low-melting glass layer, and the dielectric layer 26 is covered with a protective film 27 .
[0005] The rear panel 28 is provided with address electrodes 29 (hereinafter referred to merely as “A electrodes”) disposed on its surface facing the front panel 21 , so as to be spaced from and extend perpendicularly to the X electrodes ( 22 - 1 , 22 - 2 , . . . ) and Y electrodes ( 23 - 1 , 23 - 3 , . . . ) of the front panel 21 , and the A electrodes are covered with a dielectric layer 30 . The A-electrodes 29 are disposed so as to extend in a direction (the column direction) of an arrow D 1 shown in FIG. 2 . On the dielectric layer 30 , there are disposed partitions (ribs) 31 for separating the A-electrodes 29 from each other, thereby preventing the discharge from spreading (defining an area of the discharge). Red-, green-, and blue-light emitting phosphor layers 32 are applied sequentially in the shape of stripes on surfaces of corresponding grooves formed between the partitions 31 .
[0006] FIG. 3 is a cross-sectional view of a substantial part of the PDP as viewed in the direction of the arrow D 2 in FIG. 2 , and illustrates one discharge cell serving as the smallest unit of a pixel. In the drawing, boundaries between the discharge cells are schematically indicated by broken lines. The reference numeral 33 denotes a discharge space filled with a discharge gas for generating plasma. When a voltage is applied between the electrodes, plasma 10 is generated by ionization of the discharge gas.
[0007] FIG. 3 schematically shows a condition in which the plasma 10 is generated. Ultraviolet rays from the plasma excite the phosphors 32 to emit light, and the light from the phosphors 32 passes through the front panel 21 such that an image display is produced by a combination of light from the respective discharge cells.
[0008] FIG. 4 is a schematic illustration of movements of charged particles (positive or negative particles) in the plasma 10 shown in FIG. 3 . In FIG. 4 , the reference numerals 3 denote particles with a negative charge (e.g., electrons), the reference numeral 4 denotes a particle with a positive charge (e.g., a positive ion), the reference numeral 5 denotes a positive wall charge and the reference numerals 6 denote negative wall charges. The drawing illustrates a state of charges at an instant of time during the operation of the PDP, and the arrangement of the charges does not have any particular meaning.
[0009] FIG. 4 is a schematic illustration showing, by way of example, the state in which discharge has started and then ceased in response to application of a negative voltage to the Y electrode 23 - 1 and of a (relatively) positive voltage to both the A electrode 29 and the X electrode 22 - 1 . As a result, formation of wall charges (which is called “writing”) has been performed which assists start of discharge between the Y electrode 23 - 1 and the X electrode 22 - 1 . When an appropriate inverse voltage is applied between the Y electrode 23 - 1 and the X electrode 22 - 1 on this occasion, discharge occurs in a discharge space between the both electrodes via the dielectric layer 26 (and the protective film 27 ). After cessation of the discharge, when the voltage applied between the Y electrode 23 - 1 and the X electrode 22 - 1 are reversed, another discharge occurs. The discharge can be produced continuously by repeating the operation described above. This is called the sustaining discharge.
[0010] FIGS. 5A to 5C are diagrams showing the operation during one TV field period required for displaying one frame on the PDP shown in FIG. 2 . FIG. 5A is a time chart. As shown in (I), one TV field period 40 is divided into a plurality of sub-fields 41 through 48 having different number of times of light emission from one another. The gray scale is represented by selecting either one of emission and non-emission in each of the sub-fields. As shown in (II), each of the sub-fields has a resetting period 49 , an address discharge period 50 for determining a light-emitting cell, and a sustaining discharge period 51 .
[0011] FIG. 5B shows voltage waveforms applied to the A electrodes, X electrodes and Y electrodes during the address discharge period 50 of FIG. 5A . A voltage waveform 52 is a waveform of a voltage applied to one of the A electrodes during the address discharge period 50 , a voltage waveform 53 is a waveform of a voltage applied to the X electrodes, and voltage waveforms 54 and 55 are waveforms of voltages applied to the ith and (i+1)th Y electrodes, respectively, and the above voltages are denoted by V 0 , V 1 , and V 2 (V), respectively. In FIG. 5B , a width of the voltage pulse applied to the A electrodes is indicated by t a . According to FIG. 5B , when a scan pulse 56 is applied to the ith Y electrode, the address discharge occurs in the cell located at an intersection of the ith Y electrode and the A electrode 29 . Further, even when the scan pulse 56 is applied to the ith Y electrodes, the address discharge does not occur if the A electrode 29 is at ground potential (GND). In this way, the scan pulse 56 is applied once to the Y electrode during the address discharge period 50 , and in synchronism with the scan pulse 56 , the A electrode 29 of the cell intended to produce light is supplied with the voltage V 0 , and the A electrode of the cell not intended to produce light is set to the ground potential. In the discharge cell where the address discharge has occurred, the charges produced by the discharge are provided on the surfaces of the dielectric layer and the protective film covering the Y electrodes. With the aid of an electric field generated by the charges, on-or-off control of the sustaining discharge can be obtained as described later. That is to say, the discharge cells having produced the address discharge serve as light emitting cells, and the remainder of the cells serves as dark cells.
[0012] FIG. 5C shows voltage pulses applied all of the X electrodes and Y electrodes which serve as the sustaining discharge electrodes during the sustaining discharge period 51 in FIG. 5A . A voltage waveform 58 is applied to the X electrodes and a voltage waveform 59 is applied to the Y electrodes. The pulses with the voltage of V 3 (V) of the same polarity are applied alternately to the X electrodes and Y electrodes, and consequently, reversal of the polarity of the voltage between the X and Y electrodes is repeated. The discharge caused in the discharge gas between the X electrodes and Y electrodes generated during this period is called the sustaining discharge. The sustaining discharge is performed alternately in a pulsed manner.
[0013] Further, as described in JP-A-2006-216556 and JP-A-2006-147538, regarding the electrode structure, there is proposed a structure of using a floating electrode disposed inner from the X electrodes and Y electrodes in parallel to the X electrodes and Y electrodes for the purpose of improvement in brightness, reduction of the discharge starting voltage, reduction of the manufacturing cost, and improvement in image quality. Still further, as described in JP-A-2001-216902, there is also proposed a structure of using a floating electrode in a part opposed to the partition for the purpose of effectively preventing interference in discharge between the discharge cells adjacent to each other, and thereby performing stable image display. Further, as described in JP-A-2001-6564 and JP-A-2002-343257, there is also proposed a structure of arranging the area where the sustaining discharge electrodes used as the scan electrodes are opposed to the address electrodes is larger than the area where the sustaining discharge electrode not used as the scan electrodes are opposed to the address electrodes.
SUMMARY OF THE INVENTION
[0014] In the case in which it is attempted to achieve the PDP, which is bright, has guaranteed life, can be driven stably, and is of low power consumption, high definition, and high image quality, the address discharge timelag becomes a bottleneck. If the address discharge timelag becomes large, a failure in the address discharge is caused, and the subsequent sustaining discharge fails, thus causing flickers on the screen. Further, in addition, driving the PDP for a long period of time causes the problem (deterioration with age) of increasing the address discharge timelag. Specifically, when the PDP is kept on for a long period of time, the flickers on the screen occur to cause degradation of the image quality.
[0015] As described in JP-A-2006-216556 and JP-A-2006-147538, there is proposed a structure of using the floating electrode disposed inner from the X electrodes and Y electrodes in parallel to the X electrodes and Y electrodes. However, in such a structure, since the floating electrode is disposed so as to traverse the center section of the discharge cell for the purpose of supporting the sustaining discharge, deterioration of an MgO surface on the floating electrode is caused by the sustaining discharge, thus making it quite difficult to prevent the deterioration of the address discharge timelag with age. Further, the deterioration of the address discharge timelag is not improved even by using the floating electrode to the part opposed to the partition as described in JP-A-2001-216902. Further, even if the area where the sustaining discharge electrodes used as the scan electrodes are opposed to the address electrodes is arranged to be larger than the area where the sustaining discharge electrode not used as the scan electrodes are opposed to the address electrodes as described in JP-A-2001-6564 and JP-A-2002-343257, the positive effect of the floating electrode can hardly be obtained because the floating electrode is not disposed at an appropriate place.
[0016] The present invention has been made in view of the circumstances described above, and has an object of improving the deterioration of the address discharge timelag with age, thereby providing a PDP, which is bright, has guaranteed life, can be driven stably, and is of low power consumption, high definition, and high image quality.
[0017] A summary of representative aspects of the invention disclosed in the present specification will be explained below.
[0018] According to a first aspect of the present invention, there is provided a plasma display panel, including a plurality of discharge cells each having a front substrate, a bus electrode, a pair of sustaining discharge electrodes provided to the front substrate disposed in parallel to each other in a direction perpendicular to the longitudinal direction of the bus electrode, and for forming a display line, a dielectric layer for covering the pair of sustaining discharge electrodes, a rear substrate, and an address electrode provided to the rear substrate so as to be opposed to the pair of sustaining discharge electrodes, and extending in a direction perpendicular to the longitudinal direction of the bus electrode, and a plurality of partitions for separating the plurality of discharge cells, wherein a floating electrode is disposed on the same substrate as the pair of sustaining discharge electrodes so as not to pass through a center line coplanar with the floating electrode extending in a direction perpendicular to the longitudinal direction of the bus electrode and dividing the discharge cell into two equal parts.
[0019] According to a second aspect of the present invention, in the plasma display panel according to the first aspect of the invention, a length of the floating electrode in the longitudinal direction of one bus electrode is 20% of a width of the discharge cell in the longitudinal direction excluding the partitions.
[0020] According to a third aspect of the present invention, in the plasma display panel according to the first aspect of the invention, the floating electrode is formed of one of a transparent conductive film and a metal film.
[0021] According to a fourth aspect of the present invention, in the plasma display panel according to the first aspect of the invention, the floating electrode is formed in the same layer as the pair of sustaining discharge electrodes.
[0022] According to a fifth aspect of the present invention, in the plasma display panel according to the first aspect of the invention, the floating electrode is made of the same material as the pair of sustaining discharge electrodes.
[0023] According to a sixth aspect of the present invention, in the plasma display panel according to the first aspect of the invention, the dielectric layer is mainly composed of a grass layer, and an MgO film covering the glass layer.
[0024] According to a seventh aspect of the present invention, in the plasma display panel according to any one of the first through the sixth aspects of the invention, the floating electrode is formed continuously to the contiguous discharge cell in the longitudinal direction of the bus electrode.
[0025] According to an eighth aspect of the present invention, in the plasma display panel according to any one of the first through the seventh aspects of the invention, the shortest distance between the pair of sustaining discharge electrodes and the floating electrode is substantially a half of the thickness of the dielectric layer.
[0026] According to a ninth aspect of the present invention, in the plasma display panel according to any one of the first through the eighth aspects of the invention, the thickness of the dielectric layer is equal to or smaller than 25 μm.
[0027] According to a tenth aspect of the present invention, in the plasma display panel according to any one of the first through the ninth aspects of the invention, the address electrode is formed so that projective components of the floating electrode and the address electrode in a direction perpendicular to the rear substrate overlap with each other.
[0028] According to an eleventh aspect of the present invention, there is provided a plasma display panel, including a plurality of discharge cells each having a front substrate, a bus electrode, a pair of sustaining discharge electrodes provided to the front substrate disposed in parallel to each other in a direction perpendicular to the longitudinal direction of the bus electrode, and for forming a display line, a dielectric layer for covering the pair of sustaining discharge electrodes so that the pair of sustaining discharge electrodes are opposed to each other with a predetermined gap, a rear substrate, and an address electrode provided to the rear substrate so as to be opposed to the pair of sustaining discharge electrodes, and extending in a direction perpendicular to the longitudinal direction of the bus electrode, and a plurality of partitions for separating the plurality of discharge cells, wherein the floating electrode is formed in another area than the gap.
[0029] According to a twelfth aspect of the present invention, in the plasma display panel according to the eleventh aspect of the invention, the floating electrode is formed of one of a transparent conductive film and a metal film.
[0030] According to a thirteenth aspect of the present invention, in the plasma display panel according to the eleventh aspect of the invention, the floating electrode is formed in the same layer as the pair of sustaining discharge electrodes.
[0031] According to a fourteen aspect of the present invention, in the plasma display panel according to the eleventh aspect of the invention, the floating electrode is made of the same material as the pair of sustaining discharge electrodes.
[0032] According to a fifteenth aspect of the present invention, in the plasma display panel according to the eleventh aspect of the invention, the dielectric layer is mainly composed of a grass layer, and an MgO film covering the glass layer.
[0033] According to a sixteenth aspect of the present invention, in the plasma display panel according to any one of the eleventh through the fifteenth aspects of the invention, the floating electrode is formed continuously to the contiguous discharge cell in the longitudinal direction of the bus electrode.
[0034] According to a seventeenth aspect of the present invention, in the plasma display panel according to any one of the eleventh through the sixteenth aspects of the invention, the shortest distance between the pair of sustaining discharge electrodes and the floating electrode is substantially a half of the thickness of the dielectric layer.
[0035] According to an eighteenth aspect of the present invention, in the plasma display panel according to any one of the eleventh through the seventeenth aspects of the invention, the thickness of the dielectric layer is equal to or smaller than 25 μm.
[0036] According to a nineteenth aspect of the present invention, in the plasma display panel according to any one of the eleventh through the eighteenth aspects of the invention, the address electrode is formed so that projective components of the floating electrode and the address electrode in a direction perpendicular to the rear substrate overlap with each other.
[0037] According to a twentieth aspect of the present invention, there is provided an imaging system using the plasma display panel according to any one of the first through the nineteenth aspects of the invention.
[0038] By applying the above aspects of the present invention, there can be provided a PDP, in which the deterioration in the address discharge timelag with age can be improved, which is bright, has guaranteed life, can stably be driven, is of low power consumption, high definition, and high image quality.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] FIG. 1 is a diagram showing a discharge cell or a part of a discharge cell of a PDP according to an embodiment of the present invention;
[0040] FIG. 2 is an exploded perspective view showing a part of an ac coplanar-discharge type PDP with a structure of the related art;
[0041] FIG. 3 is a cross-sectional view of the structure of the PDP shown in FIG. 2 ;
[0042] FIG. 4 is a diagram schematically showing the movements of the charged particles located inside the plasma 10 shown in FIG. 3 ;
[0043] FIGS. 5A through 5C are charts each showing an operation in one TV field period for displaying a frame on the PDP;
[0044] FIG. 6 is a diagram showing a concept of the discharge timelag;
[0045] FIGS. 7A and 7B are diagrams showing a result of the observation of the enlarged MgO surface condition, wherein FIG. 7A shows the condition of the MgO surface prior to a life test, and FIG. 7B shows the condition of a part thereof deteriorated by the life test;
[0046] FIGS. 8A and 8B are diagrams showing the condition of discharge traces in the discharge cell, wherein FIG. 8A shows the condition inside the discharge cell prior to the life test, and FIG. 8B shows the condition inside the discharge cell after the life test;
[0047] FIGS. 9A through 9D show cross-sectional views of the front substrate 21 shown in FIG. 1 , wherein FIGS. 9A and 9B are cross-sectional views along the dashed lines T-T′ and U-U′, respectively, and FIGS. 9C and 9D are cross-sectional views along the chain double-dashed lines V-V′ and W-W′, respectively;
[0048] FIGS. 10A and 10B are diagrams showing a discharge cell or a part of a discharge cell of a PDP according to an embodiment of the present invention, and showing the condition of the discharge traces, wherein h 1 is 32 μm in FIG. 10A , or 15 μm in FIG. 10B ;
[0049] FIGS. 11A and 11B are diagrams each representing a result of calculation of the potential distribution on a surface of the protective film, wherein the h 1 is 32 μm in FIG. 11A , or 15 μm in FIG. 11B ;
[0050] FIG. 12 is a diagram showing a result of measurement of the number M 0 of seed electrons after the life test with the h 1 varied;
[0051] FIG. 13 is a diagram showing the optimum relationship between dn min and the h 1 ;
[0052] FIGS. 14A and 14B are diagrams showing a discharge cell or a part of a discharge cell of a PDP according to an embodiment of the present invention;
[0053] FIGS. 15A through 15I are diagrams showing a discharge cell or a part of a discharge cell of a PDP according to an embodiment of the present invention;
[0054] FIGS. 16A and 16B are diagrams showing a discharge cell or a part of a discharge cell of a PDP according to an embodiment of the present invention;
[0055] FIGS. 17A through 17C are diagrams showing a discharge cell or a part of a discharge cell of a PDP according to an embodiment of the present invention;
[0056] FIGS. 18A through 18D are diagrams showing a discharge cell or a discharge gap of a discharge cell of a PDP according to an embodiment of the present invention; and
[0057] FIG. 19 is a diagram showing an imaging system using a PDP.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0058] Hereinafter, some embodiments of the present invention will be explained in detail with reference to the accompanying drawings. It should be noted that in all of the drawings for explaining the embodiments of the invention, those having the same function are denoted with the same reference numerals, and redundant explanations therefor will be omitted.
[0059] Firstly, the address discharge timelag will be described. FIG. 6 shows a schematic diagram showing the condition of the address discharge timelag. The address discharge timelag t d is a time period from when the voltage waveform has been applied to when the address discharge occurs. Further, the address discharge timelag is divided into a formative timelag t f and a statistical timelag t s , and is defined as follows.
[0000] [Formula 1]
[0000] t d =t f +t s (1)
[0060] Here, the formative timelag t f is a period of time from when the seed electron to be a seed of the discharge has been generated to when the discharge occurs, and the statistical timelag t s is a period of time from when the voltage equal to or higher than the discharge starting voltage has been applied to when the seed electron is generated. Further, as shown in FIG. 6 , the address discharge timelag varies when the same measurement is repeatedly executed, and the varied address discharge timelags have a distribution. Therefore, in order for obtaining the discharge timelag from the results of the experiment, the following method is required. Specifically, assuming that the frequency at which the discharge occurs at a time point t i is n(t i ), the number of times N(t) of occurrence of the discharge before the time point t can be represented as follows.
[0000]
[Formula 2]
N
(
t
)
=
∑
t
i
t
n
(
t
i
)
(
2
)
[0061] Here, assuming that the number of times of measurement is N 0 , the formative timelag t f and the statistical timelag t s can be represented as follows.
[0000] [Formula 3]
[0000] 1− N ( t )/ N 0 =exp(−( t−t f )/ t s ) ( t≧t f ) (3)
[0062] Therefore, the formative timelag t f and the statistical timelag t s can be obtained from the intercept and the gradient of a graph obtained by plotting values obtained by calculating the logarithm of 1−N(t)/N 0 , which is obtained by the experiment. As shown in FIG. 6 , the formative timelag corresponding to the time elapsed until the distributions of the discharge start in a plurality of times of measurement, and the statistical timelag is a period of time corresponding to the widths of the distributions of the discharge. The formative timelag t f and the statistical timelag t s are the values necessary for understanding the discharge timelag phenomenon.
[0063] Further, in Formula 3, in the case in which the statistical timelag ts is sufficiently large, the statistical timelag independent of a fluctuation component of the formative timelag, namely a fluctuation component of the formative timelag caused by a variation in forming the wall charge and a variation in the seed electron generation position, can be obtained.
[0000] [Formula 4]
[0000] H ( t )=1 −N ( t )/ N 0 (4)
[0064] Specifically, assuming that Formula 4 works out, the period of time with which the H(t) becomes large enough not to be influenced by the fluctuation component of the formative timelag is equal to or longer than a period of time with which the H(t) becomes 0.6, the period of time with which the H(t) becomes 0.6 is t — 0.6 , and the period of time with which the H(t) becomes 0.99 is t — 0.99 , the statistical time lag ts can be represented as follows.
[0000]
[Formula 5]
H
(
t_
0.6
)
=
1
-
N
(
t_
0.6
)
/
N
0
=
0.6
(
5
)
[Formula 6]
H
(
t_
0.99
)
=
1
-
N
(
t_
0.99
)
/
N
0
=
0.99
(
6
)
[Formula 7]
t
s
=
(
t_
0.99
-
t_
0.6
)
/
1
n
H
(
t_
0.6
)
H
(
t_
0.99
)
(
7
)
[0065] Here, as shown in FIG. 6 , assuming that the voltage pulse width applied to the address electrode is t a , since the failure occurs in the address discharge to cause the flickers in the display unless all of the discharge in the plurality of times of measurement occurs within the period of time t a , it is required that all of the discharge falls within the address pulse.
[0066] Further, in the life test in which the PDP is continuously driven to be kept on, the address timelag, in particular the statistical timelag, is significantly increased. Thus, a failure in keeping the all of the discharge within the address pulse is caused resulting in the flickers in the display.
[0067] A detailed investigation has been conducted on the deterioration mechanism in the life test. As described above, the statistical timelag is the period of time from when the voltage equal to or higher than the discharge stating voltage has been applied to the electrodes to when the seed electron is generated. The seed electron to be the seed of the discharge is generated when the electron captured in the trapping level existing at a level slightly lower than the conduction band between the valence band and the conduction band of MgO jumps out to the discharge space owing to an electric field effect of the Auger process. The capturing of the electron in the trapping level is performed in the discharge prior to the address discharge by the vacuum ultraviolet irradiation on MgO, or collision of the charged particle to MgO. The longer the time elapsed from the discharge prior to the address discharge becomes, the fewer the number of the electrons captured in the trapping level becomes, and the fewer the number of seed electrons generated from the MgO surface becomes.
[0068] The number of the seed electrons can be obtained as follows. Assuming that the number of the seed electrons generated by the discharge prior to the address discharge is M 0 , and a time constant of generation (decrement of the captured electrons) of a single seed electron is τ, the number M(t) of the seed electrons with the elapsed time t after the previous discharge can be represented as follows.
[0000] [Formula 8]
[0000] M ( t )= M 0 exp(− t/ τ) (8)
[0069] Here, using the M(t) and τ, the statistical timelag t s obtained by the experiment can be represented as follows.
[0000] [Formula 9]
[0000] t s =τ/M ( t ) (9)
[0070] Therefore, according to Formulas 8 and 9, the following can be obtained.
[0000] [Formula 10]
[0000] ln(1/ t s )=ln( M 0 /τ)− t/τ (10)
[0071] Here, by measuring the statistical timelag t s while varying the elapsed time t after the discharge prior to the address discharge, and plotting the result, the M 0 and the τ can be obtained from the intercept and the gradient thereof.
[0072] As a result, it proved that the number M 0 of the seed electrons generated by the discharge prior to the address discharge was 1.0×10 6 , and the time constant τ of generation of a single seed electron was 90 ms. Further, after executing continuous lighting for 1000 hours at 70 kHz, the M 0 was 5.0×10 4 , and the τ was 90 ms. In other words, it proved that the number of the seed electrons generated in the discharge prior to the address discharge became 1/20 while the frequency 1/τ of generation of a single seed electron was maintained. As described above, the seed electron is generated when the electron captured in the trapping level jumps out to the discharge space, and the capturing of the electron to the trapping level is performed in the discharge prior to the address discharge by the vacuum ultraviolet irradiation to MgO or the collision of the charged particle to MgO. Here, since there is almost no variation in the intensity of the discharge even after the continuous lighting for 1000 hours at 70 kHz is executed, it can be understood that the energy intensity of the vacuum ultraviolet irradiation or the charged particles for capturing the electrons in the trapping level is not reduced. In other words, the reduction of the number of seed electrons emitted to the discharge space is caused by reduction of the number of the trapping levels themselves. According to the above facts, it proved that the cause of the increase in the statistical timelag by the life test was the decrease in the number of seed electrons emitted from MgO caused by the decrease in the number of trapping levels in MgO.
[0073] Subsequently, investigation of a factor causing the decrease in the number of trapping levels in MgO was conducted. FIGS. 7A and 7B show the result of observation of the surface condition of MgO before and after the life test magnified fifty thousand times. FIG. 7A shows the condition of the surface of MgO before the life test, and FIG. 7B shows the condition of a deteriorated part after the life test. It proved that on the surface shown in FIG. 7A , there remained a clean crystal of MgO on one hand, and the surface shown in FIG. 7B was scaled and crystallinity was lost from the surface, on the other hand. As described above, the trapping levels are formed at positions slightly lower than the conduction band in the band structure of the MgO crystal, and in order for existing such levels, it is required that MgO is crystallized. The reason why the crystallinity is lost by the life test is that the crystal is broken by ions in the plasma colliding against the MgO surface.
[0074] FIGS. 8A and 8B show the result of observation of the condition of the distribution of the MgO surface condition in the discharge cell. FIG. 8A shows the condition inside the discharge cell before the life test, and FIG. 8B shows the condition inside the discharge cell after the life test. Although the X electrode and the Y electrode have T-shapes, the T-shapes are not particularly required. As shown in the drawings, a pair of sustaining discharge electrodes (the X electrode 22 - 1 and the Y electrode 23 - 1 ) are opposed to each other with a predetermined gap interposed therebetween. The gap interposed between the both electrodes is referred to as a discharge gap 66 . FIGS. 18A through 18D each show an example of the discharge gap 66 . In the drawings, the discharge gap is illustrated with cross-hatching.
[0075] As shown in FIG. 8B , it can be understood that traces called discharge traces are formed on the electrodes and the vicinity thereof after the life test. These parts are the parts shown in FIG. 7B where the crystallinity is lost from the surface of MgO. An area of the discharge cell where the discharge is generated and grows effectively without blocked by the ribs and so on is defined as an effective discharge area.
[0076] In the effective discharge area, the proportion of the area where such discharge traces were formed was 65%. In other words, it proved that the remaining 35% thereof has the clean MgO crystal shown in FIG. 7A remaining thereon.
[0077] Here, as described above, it proved that the seed electrons generated in the address discharge were generated mainly from MgO in the area of the discharge traces, namely on the electrode and the periphery thereof, and almost no seed electron was emitted from MgO in the part to which an electric field as intensive as the electric field on the electrode was not applied in the address discharge, judging from the fact that the number of seed electrons from the MgO surface generated in the discharge prior to the address discharge became 1/20, and the fact that the clean MgO crystal remains 35% of the effective discharge area.
[0078] Therefore, by arranging that the electric field is effectively applied to the areas other than the area where the discharge traces are formed, namely to the area where the clean MgO crystals remain, the seed electrons can effectively be generated, thus the discharge timelag can be improved.
[0079] Based on the above concept, the following experiments were conducted.
First Embodiment
[0080] FIG. 1 shows an embodiment related to the present invention, and is a diagram showing an electrode structure of one discharge cell. As shown in FIG. 1 , electrodes not connected to a circuit are disposed in the discharge cell. Hereinafter, the electrodes are referred to as floating electrodes 65 . The floating electrodes include those connected merely to the ground potential. A 42-inch PDP with such electrode shapes was manufactured, and the evaluation was executed taking the PDP having the electrode structure shown in FIG. 8A as a target of comparison. These PDPs were formed to have the dielectric layers 26 with a thickness of 32 μm. Further, the PDPs were formed to have the shortest distance of 16 μm between the X electrode 22 - 1 or the X bus electrode 24 - 1 and the floating electrode 65 on the X electrode side in the area where the X electrode 22 - 1 or the X bus electrode 24 - 1 and the floating electrode 65 on the X electrode side were closest, and similarly, the shortest distance of 16 μm between the Y electrode 23 - 1 or the Y bus electrode 25 - 1 and the floating electrode 65 on the Y electrode side in the area where the Y electrode 23 - 1 or the Y bus electrode 25 - 1 and the floating electrode 65 on the Y electrode side were closest.
[0081] The results obtained are shown in Table 1. The address discharge timelag t d , the formative timelag t f , and the statistical timelag t s were the values with the elapsed time t after the previous discharge of 16 ms. Further, the results were obtained with the life test in which the lighting period of time was 1000 hours, and the frequency was 70 kHz.
[0000]
TABLE 1
LIGHTING
τ
PERIOD (h)
t d (μs)
t f (μs)
t s (μs)
M 0
(ms)
PRESENT
0
0.65
0.43
0.22
1.1 × 10 6
90
INVENTION
1000
1.32
0.44
0.88
2.8 × 10 5
90
(FIG. 1)
STRUCTURE
0
0.69
0.44
0.25
1.0 × 10 6
90
OF
1000
4.90
0.45
4.45
5.0 × 10 4
90
RELATED
ART (FIG.
8A)
[0082] As is understood from the table, since the number M 0 of the seed electrons becomes 1/20 after the 1000 hour life test in the structure of the related art, the statistical timelag t s becomes as very large as 4.45 μs, thus the flickers in the display are caused by miss addressing. In contrast, it proves that according to the electrode structure of the present embodiment of the invention, the number M 0 of the seed electrons after the 1000 hour life test becomes only ¼, thus the statistical timelag t s can significantly be reduced to 0.88 μs. Therefore, by using the electrode structure of the embodiment of the invention, the sufficient address discharge is possible, thus the display performance can be assured without causing the flickers in the display. The reason why the deterioration in the address discharge timelag, in particular in the statistical timelag with age can be reduced by using the electrode structure of the embodiment of the invention as described above is as follows.
[0083] As described above, the reason why the number M 0 of the seed electrons is reduced after the life test is that the crystals of MgO are broken, thus the trapping level involved in the electron emission is lowered. Further, in order for making the electrons be emitted from the part where the crystals of MgO are not broken, application of an intensive electrical field is required. Alternatively, it is required that the intensive electrical field is locally applied to the tip of a fine structure of the MgO surface. According to the electrode structure of the embodiment of the present invention, although the MgO crystals on the X electrode and the Y electrode are broken by sputtering with the sustaining discharge, the MgO crystals on the floating electrodes are not sputtered with the sustaining discharge, and remain as clean crystals after the life test because the MgO crystals on the floating electrodes are insulated from the circuit. Further, in the address discharge, since an intensive electrical field (including an intensive local electrical field) is induced on the MgO surface by electrostatic induction to promote generation of the seed electrons, the seed electrons are effectively generated, and this state is maintained after the life test.
[0084] FIGS. 9A through 9D show the cross-sectional views of the structure shown in FIG. 1 . FIGS. 9A and 9B are cross-sectional views along the dashed lines T-T′ and U-U′, respectively, and FIGS. 9C and 9D are cross-sectional views along the chain double-dashed lines V-V′ and W-W′, respectively. Here, dn (n=1, 2, . . . , 12) represent the shortest distances between the X electrode 22 - 1 , the X bus electrode 24 - 1 , the Y electrode 23 - 1 , or the Y bus electrode 25 - 1 and the floating electrodes 65 as shown in the drawings. Further, the h 1 denotes the thickness of the dielectric layer 26 . The result of the study about the thickness of the dielectric layer and the lengths of the dn will be explained in a second embodiment of the invention.
[0085] Although the floating electrodes 65 are made of the same material as the material of the X electrode 22 - 1 and the Y electrode 23 - 1 , the same material as the material of the X bus electrode 24 - 1 and the Y bus electrode 25 - 1 can also be used. Further, any materials can be used providing the materials cause the electrostatic induction. Further, although the floating electrodes 65 are formed in the same layer as the layer of the X electrode 22 - 1 and the Y electrode 23 - 1 , the floating electrodes 65 can also be formed in the same layer as the layer of the X bus electrode 24 - 1 and the Y bus electrode 25 - 1 . Alternatively, the floating electrodes 65 can also be formed between the dielectric layer 26 and the protective film 27 .
Second Embodiment
[0086] FIGS. 10A and 10B show an embodiment related to the present invention, and are diagrams showing an electrode structure of one discharge cell. As shown in the drawings, the electrodes insulated from the circuit are disposed inside the discharge cell in a floating manner. The condition of the discharge traces 62 after the life test for 1000 hours at 70 kHz is shown in the drawings. FIG. 10A shows a PDP with the h 1 of 32 μm, and FIG. 10B shows the case with a PDP with the h 1 of 15 μm.
[0087] As is understood from the drawings, in the case with the h 1 of 32 μm, it can be appreciated that the discharge traces 62 run off the electrodes. On the other hand, in the case with the h 1 of 15 μm, it can be appreciated that the discharge traces 62 substantially overlap the electrodes. The reason why the shapes of the discharge traces vary in accordance with the h 1 even if the shapes of the electrodes are the same is as follows.
[0088] When a voltage is applied to the X electrode and the Y electrode, electrical potential is formed in the discharge space via the dielectric layer 26 and the protective layer 27 . FIGS. 11A and 11B show diagrams representing calculation results of the potential distribution on the surface of the protective layer. FIG. 11A shows the case with the h 1 of 32 μm, and FIG. 11B shows the case with the h 1 of 15 μm. As is understood from the drawings, it can be appreciated that in the case in which the thickness of the dielectric layer 26 is small, the potential distribution in the discharge space (or the surface of the protective layer 27 ) strongly reflects the shapes of the electrodes. Thus, the ions in the plasma collide hard against the MgO surface on the electrodes. In contrast, in the case in which the thickness of the dielectric layer 26 is large, the potential distribution in the discharge space (or the surface of the protective layer 27 ) is spatially dampened, thus the ions in the plasma collide against the MgO surface on the electrodes and the periphery thereof. Therefore, the discharge traces 62 are also generated at places slightly running off the electrodes.
[0089] Here, it is preferable to prevent the sputtering of MgO on the floating electrodes 65 caused by the ion impact. Therefor, the number MO of the seed electrons after the life test was measured while varying the h 1 . The length of the dn is 16 μm. The results obtained are shown in FIG. 12 . The h 1 was varied to 42 μm, 32 μm, 25 μm, 15 μm, and 8 μm. It proves that the number M 0 of the seed electrons increases as the thickness of the dielectric layer decreases. Further, it is understood from the drawing that the number M 0 of the seed electrons is rapidly decreased when the dielectric layer becomes thicker than 25 μm. This is because the extent of dampening in the potential distribution in the discharge space (or the surface of the protective layer 27 ) is enhanced.
[0090] Here, the minimum value of the dn is assumed to be dn min . The optimum range of the dn min when the h 1 is varied was considered. As described above, in the case in which the thickness of the dielectric layer 26 is large, the potential distribution in the discharge space (or the surface of the protective layer 27 ) is spatially dampened, thus the ions in the plasma collide against the MgO surface on the electrodes and the periphery thereof, and consequently, the discharge traces 62 run off the electrodes. The relationship between the length of the running off and the h 1 was investigated. As a result, it proved that the length of the running off was roughly a half of the h 1 . Therefore, the dn min is preferably longer than a half of the h 1 , and if the dn min is shorter than a half of the h 1 , the influence of the sputtering by the ion impact becomes significant. According to this fact, the optimum relationship between the dn min and h 1 became clear. Specifically, the relationship can be represented by the following formula. Further, FIG. 13 shows the relationship as a shaded area.
[0000]
[Formula 11]
dn
min
≥
h
1
2
(
n
=
1
,
2
,
…
,
12
)
(
11
)
[0091] As shown in FIGS. 14A and 14B , a PDP having the floating electrode(s) disposed in the discharge cell was manufactured.
[0092] The h 1 is 25 μm, and the dn min is 13 μm. As shown in the drawings, the broken line P-P′ is drawn in parallel to the partition 31 (perpendicular to the X bus electrode 24 - 1 and the Y bus electrode 25 - 1 ) so as to pass through the center point of the discharge cell, and the broken line Q-Q′ is drawn in parallel to the X bus electrode 24 - 1 and the Y bus electrode 25 - 1 so as to pass through the center point of the discharge cell. FIG. 14A shows the PDP formed to have the floating electrode 65 disposed so as to pass through the center point of the discharge cell, and FIG. 14B shows the PDP formed to have the two identical floating electrodes 65 disposed along the Q-Q′ line and at positions furthest from the center point of the discharge cell within the effective discharge area. Here, the area of the floating electrode 65 shown in FIG. 14A and the total area of the two floating electrodes 65 shown in FIG. 14B were made equal. The life test for 1000 hours at 70 kHz was executed.
[0093] As a result, in the PDP shown in FIG. 14A , substantially the same result was obtained regarding the number M 0 of the seed electrons as the result in the case with the structure without the floating electrode 65 after the life test. After a detailed observation of the condition of the MgO surface on the floating electrode 65 in the discharge cell shown in FIG. 14A , the discharge traces were observed, and it proved that the crystallinity was lost from the MgO surface as shown in FIG. 7B . This is caused by the fact that in the case in which the floating electrode is disposed at the intersection of the lines P-P′ and Q-Q′, namely the center of the discharge cell, the discharge occurs also on the floating electrode 65 in the sustaining discharge, thus the ions collide against the MgO surface to cause deterioration of the MgO surface.
[0094] On the other hand, in the PDP shown in FIG. 14B , after the life test, there is obtained the effect of increasing the number M 0 of the seed electrons three times as many as the number in the case with the structure without the floating electrode 65 . After a detailed observation of the condition of the MgO surface on the floating electrode in the discharge cell shown in FIG. 14B , almost no discharge traces was observed. It proved that the condition of the MgO surface was as shown in FIG. 7A , and almost no crystallinity was lost from the MgO surface. This was because the floating electrodes were disposed at the positions distant from the intersection of the lines P-P′ and Q-Q′, namely the center of the discharge cell and close to the partitions as shown in FIG. 14B , thereby making it possible to prevent the discharge from occurring on the floating electrodes 65 in the sustaining discharge, thus preventing the MgO surface from deteriorating. However, this advantage of the floating electrodes 65 is enhanced in the case in which the floating electrodes are located between the discharge gap and the X bus electrode 24 - 1 or the Y bus electrode 25 - 1 as the structure shown in FIG. 1 rather than the case in which the floating electrodes are located in the discharge gap between the X electrode 22 - 1 and the Y electrode 23 - 1 . This is understood from the comparison of the number M 0 of the seed electrons after the life test described above.
[0095] The lengths of the floating electrodes 65 in the Q-Q′ direction (the lengths from the partitions 31 towards the center of the discharge cell along the Q-Q′ line) are preferably 20% of the length of the effective discharge area in the Q-Q′ direction (the length between the partitions 31 in the effective discharge area) from the respective sides. If the lengths exceed the desired values, the influence of the discharge sputtering in the sustaining discharge is exerted. Further, also in the structure shown in FIG. 14B , Formula 11 works out.
[0096] Further, although in the present embodiment, the shape of the floating electrode 65 is rectangular, it is obvious that the same advantages can be obtained by the floating electrode of any shapes such as shown in FIG. 15A , circle, ellipsoid, trapezoid, or polygon. Further, the same advantage can be obtained by disposing the floating electrodes at the positions shown in FIG. 15B . Further, it is also possible to dispose the floating electrode continuously in the adjacent discharge cells as shown in FIGS. 15C and 15D . Further the X electrode 22 - 1 and the Y electrode 23 - 1 can have the shapes as described in FIGS. 15E , 15 F, 15 G, and 15 H. Further, the electrode structure in which the adjacent cells have a common X bus electrode 24 - 1 and a common Y bus electrode 25 - 1 as shown in FIG. 15I can also be adopted. Further, the discharge cell having a box type partition structure in which the partitions 31 are also formed in a direction parallel to the X bus electrode 24 - 1 and the Y bus electrode 25 - 1 so as to separating the discharge cells can also be adopted.
Third Embodiment
[0097] FIGS. 16A and 16B show an embodiment related to the present invention, and are diagrams showing an electrode structure of one discharge cell. In this electrode structure, an address electrode is disposed so that the overlapping of the Y electrode 23 - 1 and the floating electrode 65 with the opposed address electrode 35 becomes large. FIG. 16A is obtained by adding the address electrode to FIG. 1 . A 42-inch PDP having such an electrode structure was manufactured. The thickness of the dielectric layer is 25 μm. The life test for 1000 hours at 70 kHz was executed on the PDP. As a result, the number M 0 of the seed electrons became 7.3×10 5 after the life test. On the other hand, the structure shown in FIG. 16B is a target of comparison, in which the address electrode is formed so that the floating electrodes 65 on the X electrode 22 - 1 side do not overlap the address electrode. The number M 0 of the seed electrons in such a electrode structure became 4.9×10 5 after the life test. From the results described above, it proves that the larger the overlapping between the floating electrodes and the address electrode opposed to each other, the larger the number of seed electrons becomes after the life test. Therefore, it proved that by increasing the overlapping between the floating electrodes and the address electrode, the deterioration in the address discharge timelag with age could be reduced.
[0098] Further, it is obvious that by arranging the address electrode so that the overlapping of the Y electrode 23 - 1 and the floating electrodes with the address electrode becomes large as shown in FIGS. 17A , 17 B, and 17 C (corresponding respectively to FIGS. 15E , 15 G, and 15 H), the same advantage that the number of the seed electrons generated from the MgO surface is increased of increasing can be obtained. The structures described above are examples, and any shapes can be adopted providing the constituents are arranged so that the overlapping of the Y electrode 23 - 1 and the floating electrodes 65 with the address electrode 35 becomes large.
Fourth Embodiment
[0099] FIG. 19 shows an example showing a plasma display device using the PDP shown in the embodiment of the present invention as explained above, and an imaging system having the plasma display device and an image source connected to each other. A driving power supply (also referred to as a driving circuit) receives a signal of a display screen from the image source, and converts the signal into a driving signal of the PDP to drive the PDP.
|
There is provided a PDP, in which the deterioration in the address discharge timelag with age is suppressed, which is bright, has guaranteed life, can stably be driven, is of low power consumption, high definition, and high image quality. There is provided a pair of sustaining discharge electrodes on the front substrate extending in a row direction for forming a display line, a floating electrode not connected to an external electrode is arranged on the same substrate as the pair of sustaining discharge electrode so as not to pass through a center line extending in a column direction and dividing the discharge cell into two equal parts, thereby intensifying the local potential of an area of the MgO surface not influenced by the sputtering by the sustaining discharge in the address discharge, promoting the electron emission from this area, and suppressing the deterioration of the address discharge timelag.
| 6
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CROSS-REFERENCE TO PRIORITY APPLICATION DOCUMENTS
This application claims the benefit of provisional patent application Ser. No. 60/327,990 filed Oct. 9, 2001, the specification and drawings of which are hereby incorporated by reference in their entirety.
TECHNICAL FIELD
The present invention relates to articulating load bearing flexible arms, particularly suited for use as surgical tissue stabilizers, and more particularly to increasing the stiffness of such an articulating column when in the locked configuration.
BACKGROUND ART
Flexible arms or, as they are often called, articulable columns, have many uses. For example, they are often used for positioning tools, article supports, or for locking measuring apparatus. In surgery, it is common practice to mount them as adjustable supporting brackets on a side rail of an operating table to support retractors, endoscopes and other surgical devices.
U.S. Pat. No. 4,949,927 discloses an articulable column and, more particularly, describes prior art columns of the ball and socket type which are flexible in their normal state and which, by application of tension from a central cable, become rigid.
Recent developments in heart surgery require stronger and more rigid adjustable brackets. In particular, a procedure has been introduced for carrying out cardiac bypass surgery without stopping the patient's heart. In this procedure, a device called a “tissue stabilizer” is used.
A specific prior art example, U.S. Pat. No. 5,727,569 teaches that the tissue stabilizer is attached to the wall of the heart by drawing a vacuum in an array of suction cups. With one or more such devices attached to the wall of the heart, the site at which the repair is to take place can be held fixed while the heart continues to beat.
A tissue stabilizer is often supported using a lockable articulating column, such as disclosed in U.S. Pat. No. 5,348,259. A lockable articulating column is described as a flexible, articulable column having a central tensioning cable strung through a series of ball and socket members. Each socket member has a conical opening with internal teeth engagable with a ball made of an elastomeric polymer. When the cable is tensioned, the sockets move toward each other and the balls become indented by the teeth of the socket. The column becomes rigid when the central cable is tensioned. Releasing the tension returns the column to the flexible state.
FIG. 1 is an elevational view illustrating a tissue stabilizer supported from the side rail of an operating table by a bracket as found in the prior art of U.S. Pat. No. 5,899,425.
The assembly in FIG. 1 includes vertical post 10 attached to side-rail 12 of an operating table (not shown) by a clamp 14 . The post 10 often has plural facets, which cooperate with the clamp to prevent rotation of the post relative to the clamp. A tension block 16 , mounted at the top of post 10 , comprises a mounting block 18 and a rotatable member 20 .
In FIG. 1 , one end of a flexible arm 24 is connected to the side of mounting block 18 opposite to the side having the rotatable member 20 . Flexible arm 24 comprises a series of articulating elements connected to one another by ball-and-socket joints. The number of ball and socket members may be increased or decreased depending on the use of the articulating column. The flexible arm 24 has a clamp assembly 26 mounted at its other end. The clamp assembly 26 holds the shank 28 of tissue stabilizer 30 .
Typically, tensioned mounting block 18 has an internal passage receiving a screw 32 . Affixed to the screw is a transverse pin riding in slots formed in opposite sides of mounting block 18 . The engagement of the pin with the slots prevents the screw from rotating relative to mounting block 18 . The threads of the screw engage internal threads in a rotatable member 20 , which also has an internal shoulder that can engage with the screw's head.
The tension cable is often a braided structure made of metal specifically built to withstand cyclical tensile fatigue. The cable may be pre-stretched to minimize further elongation of the cable caused by the application of tension. Turning the rotatable member 20 often supports cable tensions in the range of 5 to 1000 lbs.
Plastic links have a significant problem when used in a surgical theatre, they often cannot be reused due to difficulties in cleaning them. Metallic links, if feasible, would be easier to clean, reducing a costly form of surgical waste.
While there are references in the cited prior art to metal links in a flexible arm linkage assembly dating back to 1990, the inventors have only found plastic links actually in the market. The references in the cited prior art will be discussed in the next few paragraphs.
Prior art, plastic link components were found by the inventors to undergo deflections of up to a factor of 1000% for plastics such as polyethylene when tensioned. Metallic link components typically deflect by less than 50%. This difference in the materials turns out to require an entirely different approach to determining useful metallic links and their contact surfaces. The percentages used above were percent elongation derived from the reference: Materials Science and Engineering, 3 rd Edition, W. Callister copyright 1985, which is hereby incorporated by reference.
U.S. Pat. No. 4,949,927 teaches in FIG. 6 and its associated discussion about a link integrating a ball and rod made of aluminum. The inventors found that this link was inoperable, due to a low coefficient of friction. By having the low coefficient of friction, such links slipped easily, far below the point of usefulness.
U.S. Pat. No. 5,899,425 teaches ( FIG. 2 , Col. 4 , lines 7 - 11 ) “The flexible, articulating arm 24 , as shown in FIG. 2 , comprises a series of elements, preferably made of stainless steel . . . . Each element has a convex, spherical surface at one end and a concave, spherical surface at the other end.”
In the Summary of U.S. Pat. No. 5,899,425 (Column 2 , lines 35 - 57 ), “The bracket is characterized by an interference fit between the spherical balls and their sockets. The diameter of each ball is preferably . . . larger than the diameter of the socket into which it fits. The sockets are hemispherical or almost hemispherical, and their walls are sufficiently flexible to allow the balls to enter them The very small difference in diameter, and the flexibility of the socket walls, allows the balls and sockets to be engaged over an area of contact. The terms ‘area of contact’ and ‘area contact,’ . . . mean contact between a ball and a socket over a substantial area in a common sphere, greater than approximately 20% of the total surface area of the sphere, and is distinguishable from ‘line contact,’ which is contact between a ball and socket over a circular line or a narrow band having an area which is substantially less than 20% of the total area of the sphere corresponding to the larger of the ball or socket. The area of contact extends from the periphery of the socket to the envelope of the perimeter of the cable opening in the concave spherical surface and the circle defining the end of the convex spherical surface adjacent to the cable opening therein. The contact area is preferably approximately 30% to 40% of the total surface area of a corresponding sphere.”
The inventors found that U.S. Pat. No. 5,899,425 was both contradictory and inoperable in its teaching regarding metallic link components. First, maximizing the stainless steel contact area actually reduces the frictional force needed for stiffness. The disclosure from the Summary was appropriate for a plastic link component, but failed to account for the physical characteristics of stainless steel as well as alloys of iron and titanium, which do not deflect anywhere near as much as plastics.
Unlike, the prior art plastic articulating columns that are highly textured and consequently need only low tensile loads for fair rigidity, metallic link contact surfaces behave differently. This is due to the inherently lower interface friction of semi-smooth metallic mating convex and concave surfaces. Friction forces are directly proportional to these distributed contact forces. While two mating spherical surfaces would produce a large contact area, the distributed contact forces are relatively low because they are widely dispersed.
There is an additional problem with highly textured metallic contact surfaces. They would be difficult to clean, posing a health risk if reused in a surgical setting.
Note that a link will also be known herein as a bead.
The inventors know of no disclosure or teaching which provides for an effective metallic link for use in the linkage assembly of a flexible arm. What is needed is such an effective metallic link.
In summary, there is a need for increased stiffness in articulating joints, particularly in flexible arm linkage assemblies. There is a need for reusable links within a surgery, leading to needing metallic, reusable links. And there is a need for reusable links providing increased stiffness in flexible arm linkage assemblies.
SUMMARY OF THE INVENTION
The invention address the needs discussed in the background. The invention increases the stiffness of flexible arm linkage assemblies, by increasing the friction between link contacts when in a locked configuration.
One embodiment of the invention includes a flexible arm linkage assembly provided with a tensioning cable. The linkage assembly includes a first link with a first contact surface composed of a first contact material, and a second link with a second contact surface composed of a second, differing contact material. A high friction coupling between the first link and the second link is created by the first contact surface contacting the second contact surface when induced by the tensioning cable.
Each of the contact materials is primarily composed of a respective metallic compound, providing a higher coefficient of friction between the two contacting surfaces than would result from both contacting surfaces being composed of the same contacting material. The contacting materials are primarily composed of metallic compounds.
A flexible arm including the invention provides an increased range of motion and better stabilization of surgical instruments.
The contacting metallic compounds are further preferred to be primarily composed of alloys including at least one of iron, copper and titanium. The contacting metallic compounds are still further preferred to be at least two of the following: stainless steel, titanium, and nitinol, which will refer herein to Ni—Ti alloys.
Metallic links have a significant advantage when used in a surgery, they can be sterilized and reused many times. Using metal linkage assemblies reduces the waste products and lowers the costs associated with the use of flexible arms.
The invention includes increasing the overall metallic link to metallic link friction as a result of optimized contact geometry between the links, based upon the metallic composition of the contacting link surfaces.
Another embodiment of the invention includes optimization of metallic bead to metallic bead contact friction comprising the following steps. Maximizing the coefficient of friction between the first contact material of the first contact surface and second contact material of the second contact surface by selecting the first and second contact materials. Determining a ball diameter and conical angle to maximize frictional forces in static equilibrium based upon the coefficient of friction.
The inventors found that determining the ball diameter and conical angle maximizing static frictional forces required optimizing away from maximized contact area for a number of metals, including alloys of at least titanium, and iron, and in particular, stainless steel.
Using stainless steel for both contact surfaces, the inventors experimentally proved that they had discovered the first practical metallic link for flexible arms, providing significant improvement in the mechanical stiffness of the joint over typical plastic link components. This new metallic link used the interface geometry that resulted from their new approach to interface geometry determination.
The inventors further experimentally proved that they could make an even better joint using contact materials of stainless steel and titanium for the respective contact surfaces based upon the optimized interface geometry. The joint formed from the stainless steel contacting titanium beads had greatly improved stiffness over anything the inventors know of.
The invention includes methods of providing linkage assemblies using metallic links, as well as the linkage assembly and flexible arm as products of these methods.
The invention provides a flexible arm, also known as an articulating column, with the strength to stabilize devices holding a beating or stopped heart for an incision or the operation of a scope.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view illustrating a tissue stabilizer supported from the side rail of an operating table by a bracket as found in the prior art of U.S. Pat. No. 5,899,425;
FIG. 2 illustrates a flexible arm including a linkage assembly 1000 in accord with the invention providing increased stiffness when experimentally compared with several alternatives;
FIG. 3A illustrates a metallic linkage assembly as taught by the prior art;
FIG. 3B illustrates a metallic linkage assembly 1000 of FIG. 2 ;
FIG. 3C illustrates a preferred metallic linkage assembly 1000 of FIG. 2 ;
FIG. 4 illustrates experimental results obtained by testing a first link coupling to a second link as illustrated in FIGS. 3A to 3 C, each under 200 pound tension;
FIGS. 5A and 5B illustrate two links of FIG. 3B coupling with each other through a spherical convex surface contacting a spherical concave surface;
FIG. 5C illustrates two stainless steel links of FIG. 3C coupling with each other through a spherical convex surface contacting a conical concave surface;
FIG. 5D illustrates two links of FIG. 3C coupling with each other through a spherical convex titanium surface contacting a conical concave stainless steel surface;
FIG. 6A is an exploded view of item 16 and the rotatable member 20 of FIG. 2 ;
FIG. 6B shows the present invention with an alternate retraction mechanism 330 ;
FIG. 7A shows a close-up of the ergonomically designed handle 20 of FIGS. 2 and 6A ; and
FIGS. 7B , 7 C, and 7 D, illustrate handles for other commercially available articulating columns.
DETAILED DESCRIPTION OF THE INVENTION
Various embodiments built in accord with the invention will be discussed. The invention increases the stiffness of flexible arm linkage assemblies, by increasing the friction between link contacts, when in a locked configuration operating similarly to existing plastic based linkage assemblies.
The invention includes a flexible arm linkage assembly provided with a tensioning cable. The linkage assembly includes a first link with a first contact surface composed of a first contact material, and a second link with a second contact surface composed of a second, differing contact material. A high friction coupling between the first link and the second link is created by the first contact surface contacting the second contact surface when induced by the tensioning cable.
Each of the contact materials is primarily composed of a respective metallic compound, or compounds, providing a higher coefficient of friction between the two contacting surfaces than would result from both contacting surfaces being composed of the same contacting material.
FIG. 2 illustrates a flexible arm including a linkage assembly 1000 in accord with the invention providing increased stiffness when experimentally compared with several alternatives.
FIG. 3A illustrates a metallic linkage assembly as taught by the prior art.
FIG. 3B illustrates a metallic linkage assembly 1000 of FIG. 2 .
FIG. 3C illustrates a preferred metallic linkage assembly 1000 of FIG. 2 .
In FIG. 2 , linkage assembly 1000 includes a link 130 -T coupling with link 110 -S and link 100 coupling with link 110 -S. As used herein a link 110 -S will refer to a link shape 110 composed primarily of stainless steel. A link 110 -T will refer to a link shape 110 composed primarily of titanium.
A link may employ two or more distinct metallic compounds, typically one for each contact surface. Note that it is also within the scope of the invention to use separate materials within a link for the contact surfaces, as well as for the body joining the two contact surfaces.
A link 110 -TS refers to a link possessing a concave surface primarily composed of a titanium alloy, and a convex surface primarily composed of a stainless steel alloy. Note that a link 110 -ST refers to a link possessing a concave surface primarily composed of a stainless steel alloy, and a convex surface primarily composed of a titanium alloy. The concave and convex surfaces both support a tensioning cable traversing through their link.
The concave and convex surfaces preferably embody shapes, which for their materials, maximize static friction as well as kinetic friction when contacting each other under tension.
In FIGS. 2 , 3 B, and 3 C, there are four linkage shapes used, 100 , 110 , 120 and 130 . Each linkage shape includes at least one contact surface, which contact couples to a neighboring contact surface of another link. Links 100 and 130 each have exactly one contact surface, which are convex and concave, respectively. Links 110 and 120 each have two contact surfaces, one concave and the other convex.
The invention includes linkage assemblies provided with a tensioning cable and including the following. A first link forming a first contact surface composed of a first contact material. A second link forming a second contact surface composed of a second contact material. The tensioning cable traversing through the first link and the second link.
In certain embodiments, a high friction coupling between the first link and the second link is created by the first contact surface contacting the second contact surface when induced by the tensioning cable. The first contact material is distinct from the second contact material. Each of the contact materials is primarily composed of a respective metallic compound. The first contact surface, composed of the first contact material, contacting the second contact surface, composed of the second contact material, has a higher friction coefficient than results from composing both contact surfaces of either contact materials. This higher friction coefficient is preferably greater than 0.3.
Preferably, each of the respective metallic compounds is primarily composed of at least one alloy containing at least one member of the collection comprising: iron, copper, and titanium. However, other materials including other metals and alloys may be useable.
Further preferred, each of the respective metallic compounds is primarily composed of an alloy belonging to the collection comprising: stainless steel, titanium, and nitinol.
FIG. 4 illustrates experimental results obtained by testing a first link coupling to a second link as illustrated in FIGS. 3A to 3 C, each under 200 pound tension.
FIGS. 5A and 5B illustrate two links of FIG. 3B coupling with each other through a spherical convex surface contacting a spherical concave surface.
In FIGS. 5A and 5B , the spherical convex surface 112 connects with the semi-spherical concave surface 124 . The diameters of the two surfaces are preferably slightly different, with the convex semi-spherical 112 diameter being larger than the semi-spherical diameter of the interfacing concave surface 124 . Convex surface 112 and concave surface 124 form an interference fit when the two surfaces contact each other under tension. The wall of link 120 -S is sufficiently thin and resilient where the two surfaces come together to provide an area contact between the first link and the second link.
FIG. 5C illustrates two stainless steel links of FIG. 3C coupling with each other through a spherical convex surface contacting a conical concave surface.
FIG. 5D illustrates two links of FIG. 3C coupling with each other through a spherical convex titanium surface contacting a conical concave stainless steel surface.
In FIG. 5C , the spherical convex surface 112 - 2 connects with the conical concave surface 114 - 1 . The diameters of the two surfaces are preferably slightly different, with the convex semi-spherical 112 - 2 diameter being larger than the conical diameter of the interfacing concave surface 114 - 1 . Convex surface 112 - 2 and concave surface 114 - 1 form an interference fit when the two surfaces contact each other under tension. The wall of link 110 -S 1 is sufficiently thin and resilient where the two surfaces come together to provide an area of contact with each other. Percentages referenced in this paragraph were percent elongation. Taken from Reference: Materials Science and Engineering, 3 rd Edition , W. Callister copyright 1985
In FIG. 5D , the spherical convex surface 112 -T connects with the conical concave surface 114 -S. The diameters of the two surfaces are preferably slightly different, with the convex semi-spherical 112 -T diameter being larger than the conical diameter of the interfacing concave surface 114 -S. Convex surface 112 -T and concave surface 114 -S form an interference fit when the two surfaces contact each other under tension. The wall of link 110 -S 1 is sufficiently thin and resilient where the two surfaces come together to provide an of area contact with each other.
In FIGS. 5A to 5 D, the circular edge of the opening of each link is preferably concentric with the center of the imaginary sphere in which the surface lies when the links are fully engaged with each other. The edge is rounded to avoid a sharp edge that could damage the tensioning cable. The rounded edge has a very small radius of curvature to maximize the contact area of the mating convex and concave surfaces. The fact that the edge is rounded instead of sharp has negligible effect on the contact area.
The diameters of the convex and mating concave link surfaces may preferably vary over the length of the linkage assembly. This supports the need for increased strength and/or stiffness at the proximal end of the articulating arm near tension block 18 , where the applied mechanical moment is greatest. The applied moment is greatest at the proximal end of the flexible arm because the moment arm to the point of loading is greatest. Often, the flexible arm is oriented at the proximal end in a way that amplifies this effect.
The joints at the proximal end of the arm are preferably larger in diameter. This increases their rotational inertia, or resistance to rotation, in addition to providing greater frictional contact area than smaller distal beads located furthest from tension block 18 .
The greatest load-bearing link is usually the most proximal link. This link is sunk into the body of the articulating column providing a mechanical lock, prohibiting rotation of this link.
Distal links which need not provide such a great magnitude of resistance to angular displacement, due to the smaller applied moment, are preferably smaller in diameter to facilitate a lighter, less obtrusive design. This is useful in a surgery, where any protruding object may catch on fabric, tape, etc., distracting the surgical personnel.
Links preferably do not deform more than 0.01% from their relaxed circumference when fully loaded. This small deformation is achieved specifically because of the use of metal materials of the joint elements. A plastic bead would have to be impracticably thick to achieve this constraint.
Generally, the interference fit of the balls and sockets of the link, and more importantly, the significant area of contact between them, together provide the rigidity necessary for tissue stabilization in heart surgery. These features also allow the bracket to be adjusted easily and locked into its rigid condition by the application of a moderate force on the cable.
However, the rigidity of the arm can be substantially improved by improving the friction coefficient between links by differing selected materials between the links. This can be accomplished by fabricating adjacent articulating elements of differing materials, or by using coatings or other modifications to the contacting surfaces.
In the experimental data provided in FIG. 4 , the links of FIGS. 3A to 3 C, each used essentially one metallic compound.
In FIG. 4 , the bottom curve 200 shows the performance of an existing link.
In FIG. 4 , the second curve 210 is the performance of first link interface from a competitive device made of plastic.
In FIG. 4 , the third curve 220 shows the performance of an improved high friction coupling of metallic contact surfaces in accord with certain aspects of the invention. The tensioning cable induces contact between the first contact surface and the second contact surface providing a maximal static friction combined with a maximal kinetic friction between the first link and the second link through a contact region.
The experimental data present by curve 220 , uses a contact region is smaller than a maximal contact region obtained from altering at least one member of the collection comprising the first contact surface and the second contact surface. Such alterations include relatively small changes in the shapes and relative sizes of one or both contact surfaces.
In FIG. 4 , the top curve 230 shows the performance of the preferred high friction coupling. The tensioning cable induces contact between the first contact surface and the second contact surface providing a maximal static friction combined with a maximal kinetic friction between the first link and the second link through a contact region as found in curve 220 . Additionally, the contact materials are stainless steel and titanium.
The applied moment can be thought of as the amount of torque that the arm can resist before undergoing angular displacement.
The important point on these curves is where a device begins to deviate from vertical, not where it plateaus. For instance, curve 200 for Device 1 begins to move around 2 in-lbs, whereas the Ti—SS links with the preferred contact surfaces begin to mode up around 25 in-lbs.
The inventors analyzed the forces on the contact surfaces of a pair of coupling links. This lead to an insight regarding the parameters governing the static equilibrium conditions. The static equilibrium equations were solved for the maximum moment that could be supported prior to slippage at the interface. The inventors found the influence of the friction was very nonlinear.
The friction coefficient of the contacting metallic surface is preferably greater than 0.3. The friction coefficient of the contacting metallic surface is further preferred greater than 0.35. The friction coefficient of the contacting metallic surface is further preferred greater than 0.375. The friction coefficient of the contacting metallic surface is further preferred greater than 0.3875. An analysis performed by the inventors indicates that a flexible arm with a friction coefficient of 0.4 would be twice as stiff as one with a friction coefficient of 0.3.
The flexibility of an articulating column using the invention allows for an attached retractor to reach all portions of an organ, such as the heart. This is because of the small bend radius that has been made possible by the invention. The flexibility afforded by the small bend radius is possible because of the geometry and rigidity of the joints keeping the same stabilization of the organ as prior art device requiring greater bend radii.
The flexibility of an articulating column using this invention is increased over existing designs due to the conical angle at the convex and concave surfaces of the respective links.
Proximal links have a larger conical angle, afforded by their larger overall size. This increases the range of motion of the column by increasing the range of motion of the proximal links near to tension block 18 .
Smaller distal links have smaller conical angles, but also smaller distance from the articulating surface to the center of rotation, creating a uniform range of motion throughout the device.
For all links, the tension cable traverses freely through the links when the links are rotated to the extent of their articulating surfaces. This supports the range of motion being limited by the link design rather than the cable.
The rigidity of the articulating column can be attributed to increased friction resulting from a combination of geometric and materials factors.
The geometry of the two metallic contacting surfaces preferably acts to amplify the contact forces that are produced by applying tension to the tensioning cable.
In the case of certain embodiments of the invention, the spherical convex surface of one link preferably mates with a conical concave surface of another link. This mismatch produces larger contact forces distributed over a smaller relative area. With metals, the magnitude of these contact forces must exceed a threshold for static frictional forces to meet conditions of static equilibrium under a given applied moment. The radius of curvature of the convex surface is preferably large enough such to provide an adequate amount of contact area, further increasing the frictional forces.
A transition link that joins two links of different diameter may have spherical surfaces on both the convex and concave contact surfaces to facilitate the transition within the confined space. These geometric factors compliment the material selection, designed to increase the coefficient of friction between links.
Certain preferred flexible arms are fixed to the body of the clamp 18 , and the terminal element, or in some embodiments several terminal elements, may be fixed to a surgical device. In alternate embodiments all joints may be flexible.
FIG. 6A is an exploded view of item 16 and the rotatable member 20 of FIG. 2 .
In FIG. 6A , the mechanism that supports the articulating column attaches to the supporting structure using a “C” bracket 304 and a tension block 18 applies tension to the supporting structure. This connection mechanism is both secure and is capable of a rapid disconnect.
In FIG. 6A , the tension block 16 is forced down by a screw mechanism that is driven by turning handle 300 . The advantage of this pivoted handle is that the screw mechanism does not extend further than 3 mm past the upper surface of the clamp for a profile suitable for less invasive surgery.
FIG. 6B shows the present invention with an alternate retraction mechanism 330 .
This and other attachments to an articulating column are possible and those skilled in the art can make suitable modifications for attachment of at least a variety of medical tools. The usefulness of the invention is not limited in scope to medical applications. The scope of the invention is intended to cover any linkage assembly of a flexible arm needing improved rigidity.
FIG. 7A shows a close-up of the ergonomically designed handle 20 of FIGS. 2 and 6A .
In FIG. 7A , handle 20 has a helical angle suited for right-handed people to oppose the thumb when tightening the handle. Also shown is a better view of clamp apparatus 16 . Tension block 18 is driven towards “C” bracket 304 by screw 302 when turning pivot handle 300 . This exemplary embodiment is not the only attachment means to support an articulating column including the inventions linkage assembly 1000 . Those skilled in the art will appreciate that other attachments are possible and may be considered as alternate embodiments of the present invention.
FIGS. 7B , 7 C, and 7 D, illustrate handles for other commercially available articulating columns.
The present invention allows an articulating column with a greater range of motion or smaller flexible radius of curvature. This can be attributed to the conical angles used in the convex surfaces of each articulating bead, through which the tension cable passes.
In FIG. 7A , the proximal 4 beads have a conical angle of 40 degrees where as the remaining distal beads have a conical angle of 25 degrees. The larger conical angle allows for increased flexibility because the cable has more space to bend.
Although exemplary embodiments of the invention have been described in detail above, many additional modifications are possible without departing materially from the novel teachings and advantages of the invention.
For example, different dissimilar metals may be considered for different friction coefficients, different contact surfaces achieving similar static equilibrium requirements, to create the flexible arm linkage assemblies. The flexible arms may use different support attachment mechanisms and different retractors for connection to the articulating column.
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The invention includes linkage assemblies comprising coupled links with metallic contact surfaces with improved stiffness. The inventors found significant mechanical problems with all previous descriptions of metallic contact links sufficient to preclude their commercial use. These metallic contact links are a significant improvement over existing plastic ball and metal joint, or all plastic beads as found in the prior art. The invention includes methods providing these links and high friction couplings between them, as well as the linkage assemblies and flexible arms resulting from these processes.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a non-provisional of U.S. provisional patent application Ser. No. 62/181,876, filed on Jun. 19, 2015, which application is incorporated herein by reference and priority to/of which application is hereby claimed.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable
REFERENCE TO A “MICROFICHE APPENDIX”
[0003] Not applicable
BACKGROUND
[0004] Many cigar smokers prefer to use their own tobacco product as opposed to purchasing cigars that are already constructed and filled with tobacco. These users of fine, custom tobacco prefer to start with an empty shell which they prefer to purchase and then fill with their own custom tobacco filler material or other smokable material after the shell has been removed from its package.
[0005] Patents have issued for cigar products or smokable products that begin with an empty shell that is packaged in an empty or less than filled condition, thus enabling a smoker to later add his or her custom tobacco filler. For example, the Sinclair U.S. Pat. Nos. 6,321,755; 6,357,448; 6,526,986; and 7,717,119, each hereby incorporated herein by reference disclose tobacco shells that are packaged empty of contents so that a user can add his or her custom tobacco or other fill material to the shell after opening the package.
BRIEF SUMMARY
[0006] In various embodiments the present invention relates to kits for preparing smoking articles such as cigars, cigarillos, and other smokable products.
[0007] More particularly, in various embodiments the present invention relates to an improved kit including at least one smokable sheet and at least one form mandrel detachably connected to said smokable sheet, the kit being used for rolling a custom made cigar, cigarillo, and/or rolled smoking article.
[0008] In various embodiments the kit can be packaged for sale wherein the kit includes;
[0009] (a) at least one form mandrel;
[0010] (b) at least one smokable sheet, the at least one smokable sheet being in a pre-rolled state, with a longitudinal containment volume and edges that can be moved apart to provide access to the containment volume for adding a smokable filler to the containment volume;
[0011] (c) the at least one form mandrel being connected to and supporting the at least one smokable sheet in the pre-rolled state; and
[0012] (d) the at least one form mandrel and at least one smokable sheet being packaged for sale in packaging, such as in a pouch (e.g., a foil).
[0013] In various embodiments the connected at least one form mandrel can also be used during one or more steps of preparing a custom rolled smokable article such as:
[0014] (a) moving the edges apart to provide access to the containment volume;
[0015] (b) after step “a”, adding a smokable filler to the containment volume while the edges are moved apart, and
[0016] (c) after step “b”, rolling the at least one pre-rolled sheet into a custom made cigar, cigarillo, and/or rolled smoking article, including maintaining a tensile force in the at least one pre-rolled sheet during this step.
[0017] After the filling and rolling process the connected form mandrel can be disconnected from the sheet and/or rolled smoking article.
[0018] In various embodiments is provided a product including a rolled smokable tube for holding an end user's smokable fill material, comprising:
[0019] (a) a form mandrel;
[0020] (b) a smokable tube comprising a sheet of material, the sheet of material being rolled into a shaped tube that has a longitudinal bore;
[0021] (c) a longitudinal opening in the sheet of material for adding smokable fill material to the bore, and edges that can be moved apart providing access to the bore so that the smokable fill material can be added to the bore;
[0022] (d) wherein the smokable tube is packaged for sale in a wrapper with a form mandrel being connected to and supporting smokable tube in the rolled state, and the smokable tube remains rolled in a tube shape inside the wrapper after packaging, and is not filled with smokable filler to form a complete rolled smokable article.
[0023] In various embodiments is provided a rolled smokable product, comprising:
[0024] (a) a first pre-rolled smokable sheet of material, the pre-rolled sheet having a longitudinal bore;
[0025] (b) a longitudinal opening in the first pre-rolled sheet for adding smokable fill material to the longitudinal bore, and edges that can be moved apart to enlarge the longitudinal opening so that the smokable fill material can be added to the bore via the enlarged longitudinal opening;
[0026] (c) wherein the pre-rolled smokable sheet is packaged in the wrapper with a form mandrel being connected to and supporting the pre-rolled sheet in the rolled state, and the pre-rolled sheet remaining pre-rolled inside the wrapper after packaging, and is not filled with smokable filler to form a complete rolled smokable article.
[0027] In various embodiments is provided a method of constructing a rolled smokable product comprising the steps of:
[0028] (a) obtaining a sheet of smokable material wherein the sheet is connected to a form mandrel, and the sheet is rolled into a shaped tube that has an interior bore and at least two edges that can be moved apart providing access to the interior bore so that smokable fill material can be added to the interior bore;
[0029] (b) wherein, without filling the interior bore with smokable fill material, the shaped tube and connected form mandrel is packaged inside a wrapper for sale to a consumer, with the form mandrel supporting the pre-rolled sheet in the rolled state inside the wrapper;
[0030] (c) constructing a rolled smokable product from the shaped tube of step “b” by removing the shaped tube and connected form mandrel from the wrapper, moving apart the two edges, and filling the interior bore with smokable fill material, and using the connected form mandrel to roll to the sheet and smokable fill material into a rolled smokable product.
[0031] In various embodiments is provided a method of constructing a rolled smokable product comprising the steps of:
[0032] (a) providing a sheet of material that is comprised of smokable material, and connecting the sheet of material to a form mandrel;
[0033] (b) rolling the sheet of material around the form mandrel into a shaped tube that has a longitudinal bore and two edges that can be moved apart providing access to the interior bore so that smokable fill material can be added to the interior bore;
[0034] (c) packaging the shaped tube and connected form mandrel in a wrapper for sale to a consumer, and without filling the interior bore with smokable fill material; and
[0035] (d) enabling a consumer to fabricate a rolled smokable product by removal of the shaped tube and connected form mandrel from the wrapper, moving apart the two edges, filling of the interior bore with smokable fill material, and using the connected form mandrel to roll the sheet of material and added smokable fill material into a rolled smokable product, and subsequently disconnecting the form mandrel from the sheet of material and completing the process of forming the finished rolled smokable product.
[0036] In various embodiments is provided a method of constructing a rolled smokable tube product comprising the steps of:
[0037] (a) providing a sheet of material that includes smokable material and connected form mandrel;
[0038] (b) rolling the sheet of material around the connected form mandrel into a shaped tube that has a longitudinal bore and two edges that can be moved apart so that smokable fill material can be added to the longitudinal bore;
[0039] (c) packaging the shaped tube and connected form mandrel in a wrapper for sale to a consumer and without filling the longitudinal bore with smokable fill material; and
[0040] (d) wherein the connected shaped tube is to be used, after removal of the sheet of material from the wrapper and filling the longitudinal bore with smokable fill material, in rolling the sheet of material and smokable fill material into a rolled smokable tube product, with the form mandrel to be disconnected from the sheet of material only after this rolling process.
[0041] In various embodiments is provided a method of constructing a rolled smokable tube product filled with smokable filler comprising the steps of:
[0042] (a) obtaining a sheet comprised of smokable material, wherein the sheet is connected to a form mandrel and rolled into a shaped tube about the connected form mandrel, with the rolled sheet having an interior bore and two edges that can be moved apart to provide access to the interior bore and allow smokable fill material to be added to the interior bore, wherein the sheet and connected form mandrel are packaged in a wrapper for sale to a consumer, and without filling the interior bore with smokable fill material;
[0043] (b) removing the packaged rolled sheet and connected form mandrel from the wrapper, moving apart the two edges and filling the interior bore with smokable fill material, and using the connected form mandrel to construct a rolled smokable tube product by rolling the sheet with smokable filler into a rolled smokable tube whose interior bore is filled with smokable filler; and
[0044] (c) after step “b” disconnecting the form mandrel from the sheet.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0045] For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein:
[0046] FIG. 1 schematically shows assembly of a first embodiment where the adhesive is attached to the straw.
[0047] FIG. 2 schematically shows the straw being attached to the smokable sheet using an adhesive line, and then a separating sheet being placed over the smokable sheet.
[0048] FIG. 3 schematically shows the straw now attached to the smokable sheet using an adhesive line with a separating sheet being placed over the smokable sheet, and then showing the assembly being rolled to form a rolled assembly.
[0049] FIGS. 4 and 5 show two rolled assemblies being inserted into a foil and resealable pouch.
[0050] FIG. 6 schematically illustrates the steps to open the foil pouch and remove one of the rolled assemblies.
[0051] FIG. 7 shows one of the rolled assemblies being unrolled with the removal of the separating sheet.
[0052] FIG. 8 shows the rolled assembly now unrolled with a valley being formed from the memory in the smokable sheet from the previous rolling.
[0053] FIG. 9 schematically illustrates the step of adding smokable filler onto the smokable sheet where the sheet remains attached to a straw.
[0054] FIGS. 10 through 13 schematically illustrate the steps of using the smokable sheet attached to the straw in the process of rolling a finished smokable product.
[0055] FIG. 14 schematically shows the step of detaching the straw from the smokable sheet after rolling.
[0056] FIG. 15 schematically shows the step of sealing the smokable sheet after rolling.
[0057] FIG. 16 schematically shows assembly of a first embodiment where the smokable sheet is attached to the straw by being inserted into the bore of the straw through a slit, and with a separating sheet being placed on the smokable sheet.
[0058] FIG. 17 schematically shows smokable sheet attached to the straw with a separating sheet placed over the smokable sheet, and the assembly being rolled for packaging.
[0059] FIGS. 18 and 19 show two rolled assemblies being inserted into a foil and resealable pouch.
[0060] FIG. 20 schematically illustrates the steps to open the foil pouch and remove one of the rolled assemblies.
[0061] FIG. 21 shows one of the rolled assemblies being unrolled with the removal of the separating sheet.
[0062] FIG. 22 schematically illustrates the step of adding smokable filler onto the smokable sheet where the sheet remains attached to a straw.
[0063] FIGS. 23 through 25 schematically illustrate the steps of using the smokable sheet attached to the straw in the process of rolling a finished smokable product.
[0064] FIGS. 26A, 26B, and 26C schematically shows the step of detaching the straw from the smokable sheet after rolling by sliding the straw out of the rolled smoking product.
[0065] FIG. 27 schematically shows the step of sealing the smokable sheet after rolling.
[0066] FIG. 28 is a perspective view of a hollow receiving portion.
[0067] FIG. 29 is a perspective view of a sheet which can be used in making a smokable insert.
[0068] FIG. 30 is a perspective view of smokable filler.
[0069] FIG. 31 are various perspective views showing the use of a sheet and smokable filler in making a smokable insert.
[0070] FIG. 32 is a perspective view of the smokable insert about to be inserted into the hollow receiving portion.
[0071] FIG. 33 is a perspective view of the smokable insert partially inserted into the hollow receiving portion.
[0072] FIG. 34 is a perspective view of the smokable insert fully inserted into the hollow receiving portion.
DETAILED DESCRIPTION
[0073] Smokable article kit can include pre-rolled smokable sheet 300 having an interior bore 380 , said sheet 300 being rolled around and connected to form mandrel or straw 100 , with pre-rolled sheet 300 and connected form mandrel 100 being together packaged for sale in a flexible packaging 800 (such as a foil pouch) when pre-rolled smokable sheet 300 is not filled with smokable filler material 1100 .
[0074] Form mandrel/straw 100 can include first end 110 , second end 120 and have a longitudinal bore 130 . About straw 100 can be an adhesive 190 which in a preferred embodiment can be a line of adhesive and is used to connect straw 100 to smokable sheet 300 . Form mandrel can be constructed from any type of materials (preferably non-smokable materials) having the requisite properties including resistance to collapsing and supporting the pre-rolled state for pre-rolled sheet 300 including plastic, metal, wood, etc.
[0075] Smokable sheet 300 can include first face 310 , second face 320 , and have first 360 , second 362 , third 364 , and fourth 366 sides. First 360 , second 362 , third 364 , and fourth 366 sides can respectively have dimension 361 , dimension 363 , dimension 365 , and dimension 367 . Smokable sheet 300 can be constructed from any type of smokable materials including homogenized tobacco or HTM, natural leaves, cellulose, wood pulp, paper, rice paper, cigar paper, cigarette paper, vegetable, fruit, herb, etc.
[0076] Separating sheet 400 can include first face 410 , second face 420 , and have first 460 , second 462 , third 464 , and fourth 466 sides. First 460 , second 462 , third 464 , and fourth 466 sides can respectively have dimension 461 , dimension 463 , dimension 465 , and dimension 467 . Separating sheet 400 can be constructed from any type of materials (preferably non-smokable materials) having the requisite properties including cellophane, plastic, foil, etc.
[0077] Package or flexible wrapper 800 can be flexible and any shape such as rectangular. The package 800 has interior 830 that can be closed. The interior 830 can be sized and shaped to contain the combination of pre-rolled sheet 300 and connected form mandrel 100 . The package or wrapper 830 has closed end 810 and open end 820 that would enable insertion of the combination of pre-rolled sheet 300 , connected form mandrel 100 into the interior 830 . A seal 840 could be formed at in order to encapsulate the combination pre-rolled sheet 300 /connected form mandrel 100 into the interior 830 .
[0078] Connected form mandrel/straw 100 can be used to prevent compression the pre-rolled smokable sheet 300 when packaged, and can further be used to assist in the rolling process as will be described below.
[0079] In various embodiments a non-smokable separating sheet 400 can be used to resist/prevent smokable sheet 300 from sticking to itself while in the interior 830 of packaging 800 , along with retaining moisture in smokable sheet 300 .
[0080] As will be described below, in various embodiments the apparatus 10 of the present invention enables a user or smoker to support his or her custom smokable filler into hollow interior 380 of pre-rolled smokable sheet 300 after it has been removed from package or wrapper 800 .
Connection by Glue Line
[0081] FIG. 1 schematically shows assembly of a first embodiment where adhesive 190 is attached to the straw 100 . This Figure schematically shows smokable sheet 300 being attached (schematically indicated by arrow 302 ) to straw 100 , and separating sheet 400 being placed on smokable sheet 300 (schematically indicated by arrow 402 ).
[0082] FIG. 2 schematically shows an alternative embodiment where adhesive or glue 350 having a width 130 is placed on smokable sheet 300 (at edge 366 ) instead of on form mandrel/straw 100 . This Figure schematically shows smokable sheet 300 being attached to straw 100 and partially rolled about straw 100 (schematically indicated by arrow 52 ′) along with separating sheet 400 being placed on smokable sheet 300 (schematically indicated by arrow 402 ). FIG. 3 schematically shows the straw 100 now attached to the smokable sheet 300 using an adhesive line 350 with a separating sheet 400 being placed over the smokable sheet 300 , and then showing the assembly being rolled 100 (schematically indicated by arrow 52 ″) to form a rolled assembly 10 . FIGS. 4 and 5 show two rolled assemblies 10 and 10 ′ being inserted into a foil and resealable pouch 800 . Assembly 10 ′ is constructed substantially similar to assembly 10 . Each rolled assembly 10 , 10 ′ can include pre-rolled smokable sheet 300 which is pre-rolled and attached to form mandrel/straw 100 with a separating sheet 400 . The units 10 and 10 ′ are now ready for sale to a consumer who desires to make his on custom made rolled smoking product.
[0083] FIGS. 6 through 15 schematically illustrate the steps for one embodiment in making a custom made rolled smoking product.
[0084] FIG. 6 schematically illustrates the steps to open the foil 800 pouch and remove one of the rolled assemblies 10 or 10 ′. Opening of the pouch schematically indicated by arrow 802 .
[0085] FIG. 7 shows one of the rolled assemblies 10 , with edges 362 and 366 of sheet 300 being moved apart to at least partially unroll sheet 300 , and with the removal of separating sheet 400 . The moving apart and unrolling is schematically indicated by the arrows along with arrow 54 , and the removal of separating sheet 400 is schematically indicated by arrow 56 . During this moving apart and unrolling process, form mandrel/straw 100 remains connected to smokable sheet 300 , such as by glue line 350 . Also the pre-rolling of smokable sheet 300 about form mandrel/straw 100 , with such pre-rolling causing pre-rolled sheet 300 to have a “rolling” memory wherein pre-rolled sheet will tend to want to roll up again into a cylinder.
[0086] FIG. 8 shows smokable sheet 300 connected to form mandrel 100 at edge 366 via glue line 350 , and with edges 362 and 366 of sheet 300 being moved apart to provide access to interior bore 380 , and at least partially unroll sheet 300 , also creating a valley 372 from sheet 300 's rolling memory. FIG. 9 schematically illustrates the step of adding smokable filler 1100 (schematically indicated by arrow 57 ) onto the smokable sheet 300 where the sheet 300 remains attached to a straw 100 , and the filler 100 is added to valley 370 .
[0087] FIGS. 10 through 14 schematically illustrate the steps of, after edges 362 and 366 are moved apart to provide access to interior bore 380 and smokable filler 1100 has been added to the interior bore 380 of smokable sheet 300 , using the connected form mandrel/straw 100 in combination with smokable sheet 300 for rolling a finished rolled smokable product 500 .
[0088] FIGS. 10 and 11 schematically show the initial “over-lapping” of edge 362 around the added smokable filler 1100 to interior bore 380 of sheet 300 . FIG. 12 shows a complete overlapping of smokable filler 1100 , along with the process of rolling the overlapped portion (schematically indicated by arrow 65 ). Arrows 62 and 64 schematically indicate that a tensile force can be placed in at least part of sheet 300 during this rolling process, with such tensile force being placed by both pushing on connected form mandrel/straw 100 and pulling on sheet 300 , while simultaneously rolling sheet 300 and smokable filler 1100 .
[0089] Dimension 304 indicates the amount of sheet 300 and smokable filler 1100 that has been rolled. Dimension 305 indicates the amount of sheet 300 to be rolled. During the rolling process the user can place a tensile force in sheet 300 by pushing on connected form mandrel/straw 100 (schematically indicated by arrow 80 ) and pulling on the amount 304 of sheet 300 and smokable filler 1100 that has already been rolled.
[0090] FIG. 13 schematically shows the process of completely rolling (schematically indicated by arrow 65 ) sheet 300 to where the amount of sheet 300 and smokable filler 1100 that has been rolled (schematically indicated by dimension 306 ) comes into contact with form mandrel/straw 100 . After contact of rolled portion (dimension 306 ) with form mandrel 100 , continued rolling in the direction of arrow 65 ′ places an increased tensile force in sheet 300 (schematically indicated by arrows 80 ′ and 82 ′), which increased tensile force can more tightly pack the smokable filler 1100 located in the interior bore 380 of now rolled smokable sheet 300 (dimension 306 ) ultimately resulting in a custom rolled smoking product 500 which has better draw and burn than one that has less tightly packed smokable filler 1100 .
[0091] FIG. 14 schematically shows the step of detaching the form mandrel/straw 100 from the smokable sheet 300 after rolling. Adhesive 350 is preferably such that sheet 300 can be slowly peeled off of form mandrel 100 without tearing sheet 300 during the peeling process. FIG. 15 schematically shows the step of sealing the smokable sheet 300 after rolling. The same glue/adhesive 350 that is peeled off of form mandrel/straw 100 can be used to seal edge 366 of smokable sheet 300 to the outer wall of sheet 300 .
[0092] In an alternative embodiment sheet 300 can include a perforated line/area 351 immediately below glue line 350 so that sheet 300 can be torn at this perforation line losing only a small portion of sheet 300 to form mandrel 100 . In this embodiments a double glue line 350 and 352 with perforated line 351 in between double line 350 and 352 can be used so that glue line 352 can be used to seal new edge 366 to the outer wall of sheet 300 in making the finished rolled smokable product.
Connection by Slot in Form Mandrel
[0093] FIG. 16 schematically shows assembly of a second embodiment where the smokable sheet 300 is attached to the form mandrel/straw 100 by being inserted into the bore 130 of the straw 100 through a longitudinal slit 160 (schematically indicated by arrow 302 ), and with a separating sheet 400 being placed on the smokable sheet 300 (schematically indicated by arrow 402 ).
[0094] To facilitate a tight finished rolled smokable product, form mandrel/straw 100 preferably will have a diameter 150 which, as will be described below, is small compared to the diameter 550 of finished rolled smokable product 500 . In various embodiments diameter 150 is less than 50 percent of diameter 550 . In various embodiments diameter 150 is less than 50, 45, 40, 35, 33, 30, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15,14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, and 1 percent of diameter 550 . In various embodiments diameter 150 can be with a range of any two of the above referenced percentages of diameter 550 .
[0095] In various embodiments diameter 150 is less than 20 percent of the length of edge 360 before rolling starts. In various embodiments diameter 150 is less than 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, and 1 percent of the length of edge 360 before rolling. In various embodiments diameter 150 can be with a range of any two of the above referenced percentages of the length of edge 360 before rolling.
[0096] In various embodiments the length 170 of slit 160 is at least 50 percent of the length of length 140 of form mandrel/straw 100 . In various embodiments length 170 is at least 50, 60, 70, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, and 99 percent of the length 140 of form mandrel/straw 100 . In various embodiments length 170 can be within a range of any two of the above referenced percentages of the length 140 of form mandrel/straw 100 .
[0097] In this second embodiment glue line 350 for smokable sheet is preferably placed on edge 362 of smokable sheet 300 , spaced away from form mandrel 100 .
[0098] FIG. 17 schematically shows smokable sheet 300 now attached to form mandrel/straw 100 (with edge 366 inserted into slit 160 such that portion 368 is now located in the interior 130 of form mandrel/straw 100 ); with a separating sheet 400 placed over smokable sheet 300 , and the assembly being rolled for packaging, and then showing the assembly being rolled 100 (schematically indicated by arrow 52 ″) to form a rolled assembly 10 . FIGS. 18 and 19 show two rolled assemblies 10 and 10 ′ being inserted into a foil and resealable pouch 800 . Assembly 10 ′ is constructed substantially similar to assembly 10 . Each rolled assembly 10 , 10 ′ can include pre-rolled smokable sheet 300 which is pre-rolled and attached to form mandrel/straw 100 with a separating sheet 400 . The units 10 and 10 ′ are now ready for sale to a consumer who desires to make his on custom made rolled smoking product.
[0099] FIG. 20 schematically illustrates the steps to open the foil pouch 800 pouch and remove one of the rolled assemblies 10 or 10 ′. Opening of the pouch schematically indicated by arrow 802 .
[0100] FIG. 21 shows one of the rolled assemblies 10 , with edges 362 and 366 of sheet 300 being moved apart to at least partially unroll sheet 300 , and with the removal of separating sheet 400 (schematically indicated by arrow 403 ). During this moving apart and unrolling process, form mandrel/straw 100 remains connected to smokable sheet 300 , such as by slit 160 . Also the pre-rolling of smokable sheet 300 about form mandrel/straw 100 , with such pre-rolling causing pre-rolled sheet 300 to have a “rolling” memory wherein pre-rolled sheet will tend to want to roll up again into a cylinder.
[0101] FIGS. 22 through 26 schematically illustrate the steps of, after edges 362 and 366 are moved apart to provide access to interior bore 380 and smokable filler 1100 has been added to the interior bore 380 of smokable sheet 300 , using the connected form mandrel/straw 100 in combination with smokable sheet 300 for rolling a finished rolled smokable product 500 .
[0102] FIG. 22 schematically illustrates the step of adding smokable filler 1100 (schematically indicated by arrow 1102 ) onto the smokable sheet 300 where the sheet 300 remains attached to a straw 100 via slot 160 .
[0103] FIGS. 22 and 23 schematically show the process of using connected form mandrel/straw 100 to initially “over-lap” edge 362 of smokable sheet 300 around the added smokable filler 1100 . FIG. 23 shows a complete overlapping of smokable filler 1100 , along with the process of rolling the overlapped portion (schematically indicated by arrow 614 ). Arrows 610 and 612 schematically indicate that a tensile force can be placed in at least part of sheet 300 during this rolling process, with such tensile force being placed by both pulling on form mandrel/straw 100 in the direction of arrow 614 while simultaneous maintaining the position of edge 366 of sheet 300 (or also pulling on edge 366 in the direction of arrow 610 ), all while simultaneously rolling sheet 300 and smokable filler 1100 (schematically indicated by arrow 614 ). Dimension 304 indicates the amount of sheet 300 and smokable filler 1100 that has been rolled. Dimension 305 indicates the amount of sheet 300 to be rolled.
[0104] FIGS. 24 and 25 schematically illustrate the steps of using the smokable sheet 300 attached to form mandrel/straw 100 in the process of rolling a finished rolled smokable product 500 . FIG. 25 schematically shows the completion of the rolling process (schematically indicated by arrow 614 ) of sheet 300 to where the form mandrel/straw 100 can be detached from sheet 300 . Continued twisting of form mandrel/straw 100 in the direction of arrow 614 ′, while simultaneous maintaining the position of edge 366 of sheet 300 (or also pulling on edge 366 in the direction of arrow 610 ), places an increased tensile force in sheet 300 (schematically indicated by arrows 610 ′ and 612 ′), which increased tensile force can more tightly pack the smokable filler 1100 located in the interior bore 380 of now rolled smokable sheet 300 (decreasing dimension 306 ) ultimately resulting in a custom rolled smoking product 500 which has better draw and burn than one that has less tightly packed smokable filler 1100 .
[0105] FIGS. 26A, 26B, and 26C schematically shows the step of detaching the form mandrel/straw 100 from the smokable sheet 300 after rolling by sliding form mandrel 100 out of the rolled smoking product 500 (schematically indicated by arrows 66 , 67 , and 68 ). During this sliding out process, the rolled portion of smokable sheet 300 should be kept tight and from unrolling which is schematically indicated by arrow 58 in these figures.
[0106] FIG. 27 schematically shows the step of sealing the smokable sheet 300 after rolling. Glue/adhesive 350 can be used to seal edge 366 of smokable sheet 300 to the outer wall of sheet 300 .
Hollow Tube And Insertable Rod
[0107] FIGS. 28-34 show a third embodiment which comprises a hollow tube portion 910 and insertable smokable insert 950 . FIG. 28 is a perspective view of a hollow receiving portion 910 which includes first end 910 , second end 914 , filter 920 , and receiving volume 930 . In this embodiment insertable smokable insert can be received by receiving portion 910 .
[0108] FIG. 29 is a perspective view of a smokable sheet 952 which can be used in making a smokable insert 950 . Sheet 952 can have end 953 , length 954 , and diameter 955 . FIG. 30 is a perspective view of smokable filler 1100 which can be inserted into longitudinal opening or cavity 958 of smokable insert. FIG. 31 are various perspective views showing the use of a sheet 952 and smokable filler 1100 in making a smokable insert 950 .
[0109] FIG. 32 is a perspective view of the smokable insert 950 about to be inserted into the hollow receiving portion 930 of hollow tube 910 . FIG. 33 is a perspective view of the smokable insert 950 partially inserted into the hollow receiving portion 930 . FIG. 32 is a perspective view of the smokable insert 950 fully inserted into the hollow receiving portion 950 . After full insertion a finished smoking product is created and can be smoked.
[0110] The following is a Table of Reference Numerals used in this patent application:
[0000]
TABLE OF REFERENCE NUMERALS:
REFERENCE NUMBER
DESCRIPTION
10
unit
50
arrow
52
arrow
54
arrow
56
arrow
57
arrow
58
arrow
60
arrow
61
arrow
62
arrow
64
arrow
65
arrow
66
arrow
67
arrow
68
arrow
70
arrow
72
arrow
80
arrow
82
arrow
100
straw
110
first end
120
second end
130
longitudinal bore
140
length of straw
150
diameter of straw
160
slit
162
edge of slit
170
length of slit
180
outer surface of straw
190
adhesive
300
smokable sheet
301
distance from straw
302
arrow
304
rolled portion
305
portion remaining to be rolled
306
completion of rolling step
310
first face
312
dimension
320
second face
322
dimension
350
adhesive line
352
dimension
360
first side
361
dimension
362
second side
363
dimension
364
third side
365
dimension
366
fourth side
368
portion of smokable sheet inserted
into interior bore of straw
367
dimension
370
reservoir/valley
372
arrow
380
interior bore
400
separating sheet
402
arrow
410
first face
412
dimension
420
second face
422
dimension
460
first side
461
dimension
462
second side
463
dimension
464
third side
465
dimension
466
fourth side
467
dimension
500
finished smoking product
510
first end
520
second end
530
longitudinal bore
550
diameter
600
overlapped portion
610
arrow
612
arrow
614
arrow
800
package/wrapper
802
arrow
810
closed end
820
open end
830
interior
840
seal
900
finished herbal smoking product
902
dimension
910
hollow tube portion
912
first end
914
second end
920
filter
922
dimension
930
receiving volume
932
first end
934
second end
938
longitudinal cavity or opening
940
length of hollow tube portion
950
filler insert
952
sheet
953
end
954
length
955
diameter
958
longitudinal cavity or opening
960
filler
962
arrow
963
arrow
964
arrow
965
arrow
966
arrow
967
arrow
1100
smokable filler material
1102
arrow
[0111] All measurements disclosed herein are at standard temperature and pressure, at sea level on Earth, unless indicated otherwise. All materials used or intended to be used in a human being are biocompatible, unless indicated otherwise.
[0112] The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.
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A product and method of making thereof for the consumption of smokable substances such as tobacco or herbs. The product is comprised of smokable materials such as tobacco, homogenized tobacco, natural leaf materials, vegetable materials, herbal materials, paper, cellulose, and other smokable materials and has a connected form mandrel which is used during the rolling process and disconnected after substantial completion of the rolling process.
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TECHNICAL FIELD
This invention relates to enhancing the flow of agglomerates and bound materials utilizing organic materials. This invention also relates to a process for working particulate materials during agglomeration in a unique way.
BACKGROUND OF THE INVENTION
Agglomeration and binding materials is done to prevent the segregation of fine and course materials. Graphite or other alloys or alloy precursors in a fine form enhance dispersion within a greater matrix of ‘iron’ or other principle material or alloys. The particle size distribution is manipulated to attain desired performance under specific conditions. The formulation of agglomerates or filler material entails fabricability and processing considerations in addition to constituency selection.
In thermal, solvent, pressured, or activated polymer processing, the management of inputs during agglomeration or binding is critical to the achievement of a sound composite or agglomerate with out degrading the organic constituent. Insufficient inputs can cause poor bonding, porosity and irregular deposit configuration and segregation. These conditions are precursor to the formation of agglomerates having a greater disparity in compositions. Excess inputs produce dilution, fragmenting, and oxidation of the organic constituent. The effects of insufficient inputs on the sintering of the compacts made with these weak agglomerates or poorly bound materials include greater variation in production, distortion, voids, softening, or embrittlement. The effects of excess inputs during the formation of agglomerates include reduction in the effectiveness of the lubricant or mold release to aid in reduction of particle/particle or agglomerate/agglomerate friction during compaction. Increase in dusting, segregation in handling; and decrease in effectiveness in ejecting the compact from the die are problems that often occur during processing. They occur after pressing of the compact or during slurry filling of the cavities. They are the primary purpose of the mold release or lubricant in the first place.
With the aforementioned defined process, adding the working during processing attains the necessary rounded agglomerates; and enhanced flow characteristics.
The benefits of this greater flow-ability in traditional press and sinter is enhanced production speed, greater consistency in part to part production, as well as decrease in variation seen over time. This consistency is of paramount importance in decreasing the number of bad parts produced in any given manufacturing process using bound or agglomerated materials. Increasing speed of the manufacturing process during compaction and filling of cavities, decreasing capital equipment costs and labors necessary to produce parts also are achieved benefits.
BRIEF SUMMARY OF THE INVENTION
The composition and process of this invention eliminates these problems. In broad terms with particulate solids, adding organic material and working it upon resolidification in a unique way creates improved binding of the particulate solids. The particulate solids are materials such as metal, semi-metal, ceramic, glass, plastic, alloy, composite, agglomerate or other organic rubber. The organic selection should remain solid in handling and may become liquid during compaction. These materials may consist of a liquid, solid, or mixture selected from the group consisting of fatty acids; and amides, bisamides, soaps and salts of fatty acids; waxes, resins, oils, hydrogenated fats and oils, polymers, resins or mold release or friction reducing agents. With lubricity enough to enable ejection of a molded compact, flow, an adequately low molecular weight and formulation to enable clean burn off if desired. With inputs that may include either pressure, solvents, chemical activation of the polymers or resins, or thermal heat; and working so as to enhance the gluing of particulates together and rounding of the agglomerate to provide flowability.
In an example of thermal processing of a sample to be handled at room temperature, the preferred method makes a mix containing all ingredients that are to be used in this binding sequence. I then heat the mix above the melting point of the organic. As the temperature rises above the melting point, so does the materials chance for degradation increase. Keeping it slightly above its melting point for as little time as possible is a good thing for the organic. On the other hand as we raise the temperature and/or time the viscosity increases. This allows a greater wetting of the particulate surfaces and greater and more consistent distribution of the lubricant to be used as a binder. Generally working below the vapor or boiling or the lubricant and above its melting point is desirable. Preferably, the range is less then half the temperature difference between its boiling or vapor point and its melting point. Most preferably, I work as close to the melting point as possible, while still maintaining a liquid state when working and cooling begins to form the agglomerate. The heated material must be worked with a chilling device with the heat transfer potential to bring the mix down below its titer or softening point. This returns the binder to a solid. The motion or work forms rounded or more spherical agglomerates. This enhances the flowability of the agglomerates after cooling. After the chilling step, the mix can be screened to reduce the range of the agglomerates and create an even more consistent flow.
DETAILED DESCRIPTION OF THE INVENTION
In thermal processing, the process step of heating the mix means heating above the melting point of the organic material. The process includes the steps of using heated material so that upon cooling, it freezes and “glues the particles together”. By taking heated material and working it during cooling, the creation of rounded agglomerates is possible. Extending the subsequent heating and cooling to multiple materials with tiered melting points allows for paired or coupled pre-alloys to be distributed within the greater bound mix.
Other methods include the following steps. Multiple binding levels using multiple materials with tiered melting points. Examples used are pre-bound mixes, which will ultimately allow precursors of complex inter-structural alloys to form within the matrix of a component (multi-matrix composites). This allows for paired of coupled pre-alloys to be distributed within a greater bound mix. Using solvents of pressure instead of heating to force the wetting of the lubricant made binder also is possible. In addition, I can use chemical activation of the polymers or resins.
Solvent activation refers to the organic material dissolved in a solvent with the particulate solids. The preferred process includes the steps of using solvents so that upon evaporation of the solvent, it glues the particles together. This process takes materials that have had the organic portion dispersed in a solvent and works them during evaporation of the solvent in such a way as to form rounded agglomerates.
Pressured material refers to either adding or reducing the pressure of an organic material with particulate solids. At atmospheric pressures, this process includes the steps of using pressured material so that it phase changes into a liquid or vapor and re-solidifies upon returning to atmospheric or room pressure “gluing the particles together”. The process also includes taking pressured material and working it during re-solidification or its return to atmospheric or room pressure in such a way that the creation of rounded agglomerates is possible.
Chemically activating the polymers or resins and working the mix also forms rounded agglomerates.
The organic lubricant or binder may consist of a liquid, solid, or mixture selected from the group consisting of fatty acids; and amides, bisamides, soaps and salts of fatty acids; waxes, resins, oils, hydrogenated fats and oils, polymers or mold release or friction reducing agent. With lubricity enough to enable ejection of a molded compact, flow, an adequately low molecular weight and formulation to enable clean burn off is desired.
In one aspect, this invention relates to powder metallurgy compositions containing elemental and/or pre-alloyed non-ferrous metal powders, organic lubricants, with or without flake graphite additive. For example, pre-blended bronze compositions are commonly used for self-lubricating bearing and bushings, oil impregnated bearings for motor use, household appliances, tape recorders, video cassette recorders, etc. In commercial powder metallurgy practices, powdered metals are converted into a metal article having virtually any desired shape.
The metal powder is firstly compressed in a die to form a “green” pre-form or compact having the general shape of the die. The compact sintered at an elevated temperature to fuse the individual metal particles together into a sintered metal part having a useful strength and yet still retaining the general shape of the die in which the compact was made. Metal powders utilized in such processes are generally pure metals, or alloys or blends of these and sintering will yield a component having between 60% and 95% of the theoretical density. If particularly high-density low porosity is required, then a process such as hot isostatic pressing, explosive compaction, or double mold double sinter may be utilized. Bronze alloys used in such processes comprise a blend of approximately 10% of tin powder and 90% of copper powder and according to one common practice the sintering conditions for the bronze alloy are controlled that a predetermined degree of porosity remains in the sintered part. Such parts can then be impregnated with oil under pressure or vacuum to form a so-called permanently lubricated bearing or component. These parts have found wide application in bearing and motor components in consumer products and eliminate the need for periodic lubrication of these parts during the useful life of the product. Solid lubricants can also be included and these are typically waxes, metallic/non-metallic stearate, graphite, lead and tin alloys, molybdenum disulfide and tungsten disulfide, bismuth as well as many other additives. However, the powders produced for use in powder metallurgy have typically been commercially pure grades of copper powder and tin powder which are then mixed in the desired quantities.
For many metallurgical purposes, the resulting sintered product has to be capable of being machined that is to say it must be capable of being machined without either “tearing” the surface being machined to leave a “rough” surface or without unduly blunting or binding with the tools concerned. It is the common practice for a proportion of lead, tin, MnS, or other solid lubricant up to 10% to be introduced to aid and improve the machine-ability of the resulting product.
Metallic binders such as cobalt, zirconium, tin, copper, silver, gold, bismuth can hold higher melting point particulates together into a composite. Application can be whole particles having a single chemistry, examples being a metallic carbide of tungsten, silicon, titanium, or other hard materials such as diamond like materials, glasses, oxides, nitrates, and other similar substances; or processed particles having a deposition, film, or surface modification. Examples of this second class of materials include a material which is only moderately hard, having a hardness which in itself is not sufficient. In this case, a deposition, film or surface modification may be used examples being electroplating, ion beam, physical or chemical vapor deposition. Besides obtaining a greater particle surface hardness, a composite of greater hardness can be achieved utilizing materials made with particles processed in this way. Among the materials of greater hardness that can be deposited by means of a physical or chemical vapor deposition include silicon-carbides, the carbides and nitrites of metals especially transition metals including and the form of carbon with cubic crystallographic lattice and others such as cubic-boron-nitrate. There are many known processes for the physical or chemical deposition by vapor which can be used to obtain a layer of silicon carbide, or of other material of greater hardness. Among these processes, the ones that are particularly advantageous are CVD, PVD, PE-CVD. Once again agglomerates can be formed utilizing either or both of these particulates with a metallic binder by adding an organic material, heating the mixture to a temperature above the melting temperature of the organic material; maintaining the temperature above the melting temperature of the organic material; and slowly cooling and simultaneously working the heated mixture to below the softening point of the organic material to coat the particles with the metal binder and form rounded agglomerates.
One example is the case of thermal activation of metallic binders such as cobalt, and zirconium is used with tungsten carbide. It is useful to disperse the binder as a film over the particles and agglomerate to prevent segregation. Intermediary agglomeration using organic material may be used to “glue the metallic binders to the hard materials”. Adding an organic material and heating the mixture to a temperature above the melting temperature of the organic material; maintaining the temperature above the melting temperature of the organic material; and slowly cooling and simultaneously working the heated mixture to below the softening point of the organic material forms rounded agglomerates of the cooled mixture. The difficulty of handling and transferring hard, coarse and sharp materials is greatly aided by use of rounding agglomerates made from these products. After the organic material aids in reducing particle/particle or agglomerate/agglomerate friction and the parts release from the mold. Subsequent processing will reduce the organic materials and melt the metallic binder so that it glues the hard particles together in the compact.
In another aspect, this invention relates to powder metallurgy compositions containing elemental and/or pre-alloyed non-ferrous metal powders with organic lubricants. For example pre-blended aluminum powders are used for their ability to oxidize, workability, conductivity, as pigments and glitters, or relative lightness when compared to steel. Uses include fuel cells, household appliances, pigments, and foils, sprayed onto plastic to decrease permeability or escape of rare gases, or decrease the introduction of air into products such as food. In commercial powdered metallurgy practices flame spray or conversion into a metal article having virtually any desired shape.
In conventional press and sinter manufacturing the powder or agglomerates are firstly compressed in a die to form a “green” pre-form or compact having the general shape of the die. The compact is then sintered at an elevated temperature to fuse the individual agglomerates or metal particles together into a sintered metal part having a useful strength and yet still retaining the general shape of the die in which the compact was made. Metal powders utilized in such a processes are generally pure metals, or alloys or blends of these and sintering will yield a component having between 60% and 95% of the theoretical density. If particularly high-density low porosity is required, then processes such as hot isostatic pressing or explosive compaction may be required.
Aluminum alloys used in such processes comprise a blend of aluminum with one or more other elements or alloys such as boron, bismuth, chromium, copper, iron, magnesium, sodium, nickel, lead, silicon, tin, strontium, titanium, zinc, zirconium.
The cooling or chilling of this invention may vary widely. Typically the cooling depends upon the melting and softening temperature of the organic material. I prefer that the cooling be as rapid as possible. Often, the cooling occurs in less than one minute and could be only a few seconds. However, the cooling may take as long as a few minutes; e.g. up to 5 minutes. Cooling may even take hours or days depending upon the materials.
EXAMPLE I
In attempting to mold a cam shaft cover, weight 24.0 grams with Alcoa 201 AB and holding a 0.40 gram weight tolerance, the following was observed.
Alcoa 201 AC is a blend comprised of #1202 Aluminum which is air atomized in Texas; #3014 a 50/50 copper/Aluminum master alloy is also atomized in Texas; elemental magnesium, and Acrawax C atomized as a lubricant.
The blend contains
Min
Max
#1202 aluminum
93.60%
98.70%
#3014 50/50 aluminum/copper
0.25%
4.4%
Magnesium
0.5%
1.0%
With organic lubricant
1.5%
Trade name Acrawax aka
N,N′-Ethylenebisstearamide 65% \
N,N′-Ethylenepalmitamide 35% >
Fatty Acid (C14-18) 2% /
Mesh
size
˜5
Material
+50
+100
+200
+325
−325
microns
1202
0.2%
18-22%
26-29%
16-20%
27-40%
Aluminum
max
3014 50/50
0.2%
75-90%
copper/alum
max
Magnesium
100%
Acrawax
100%
50%
Alcoa 201 AB as received
Alcoa 201 AB Processed
Press
Grams of variation
For agglomeration and flow
Speed
in set of 30
Grams of variation in group of 30
7-8
.58
10
6.07
.22
14
.31
20
.44
The mix was heated in the chamber in inert atmosphere to a temperature above the melting point of the Acrawax in this case 180° C. for 5 minutes (Acrawax melts at 145° C.). Acrawax has a boiling point of about 415° C. Working the material during cooling produced rounded agglomerates. The working and cooling was carried out for a period of time less than 1 minute. Acrawax is a registered trademark of Glyco Inc.
EXAMPLE II
Another example of a sample holding —100 mesh of Ampal was made according to the procedure of Example I. This was a standard operating size so no changes were required to production.
The blend contains
Min
Max
Aluminum
93.60%
98.70%
Copper
3.6%
4.0%
Magnesium
0.8%
1.2%
Silicon
0.65%
0.9%
With organic lubricant
1.5%
Trade name Acrawax aka
N,N′-Ethylenebisstearamide 65% \
N,N′-Ethylenepalmitamide 35% >
Fatty Acid (C14-18) 2% /
Mesh
size
˜5
Material
+50
+100
+200
+325
−325
microns
Aluminum
1.0%
25-45
30-50
20-40
max
Copper
100%
18-24
Magnesium
100%
18-24
Silicon
100%
18-24
Acrawax
100%
5-6
Ampal 2712 processed
For agglomeration and flow
Press Speed
Grams of variation in group of 30
10
.18
14
.16
20
.22
EXAMPLE III
A metallurgic bronze powder system comprised of 90% elemental copper and 10% elemental tin was pre-alloyed, atomized and reduced to a powder. The bronze powder and Acrawax—C atomized the lubricant to be made a binder, were loaded into a crucible or melting chamber. The mix was heated in the chamber in inert atmosphere to a temperature above the melting point of the Acrawax in this case 180 C. for a 5 minutes (Acrawax melts at 145 C.). Working the material during cooling produced rounded agglomerates.
The results show a greater consistency of die filling due to binding and flow-ability of the mix. Larger particles usually accompany higher permeability allowing for greater flow rates. Agglomerate shape dictates the mixes free motion. The agglomerate ability to roll past other agglomerated particles.
The results also show binding retards sifting segregation and facilitates greater homogeneity of alloy distribution regardless of particle size. This narrows the range of strength of a compact as measured across a narrow cross-section hence increasing strength as measured from the lesser number. Less distortion of deformation of the component also is seen after sintering.
Multiple pre-bound materials mixed together to allow for creation of alloy pins, inclusions, nodes and structure within a greater component is also possible, in addition to multiple matrix components.
The process has less dusting which helps with equipment uptime due to cleanliness, consistency of die filling, housekeeping, health, benefits due to reduction of nuisance dust and the reduction of potential explosions due to air borne oxidizing or reactive materials. The agglomerates may also be ionized facilitating transfer to or from a charged target.
Lubricant as a binder, reduction of particle/particle or agglomerate/agglomerate friction during compaction and reduction of die wall friction during ejection occurs, over a process using less lubricant and more binder. Indications are that typically compressibility is decreased slightly, the lubricant is now fixed by the process and not free flowing. If the temperature of the tools are below the melting point of the bound lubricant and it achieves liquid state during compaction; compressibility is restored as the lubricant is dislocated and the bound lube is squeezed out to the die wall where it may better aid in ejection after compaction. These relatively chilled tools must freeze the binder and with subsequent relative cooling protect the part from free mix sticking to the part.
In addition to these embodiments, persons skilled in the art can see that numerous modifications and changes may be made to the above invention without departing from the intended spirit and scope thereof.
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In broad terms, this process adds organic material to particulate solids and works the mix. Resolification in a unique way creates improved binding of the particulate solids. The particulate solids are materials such as metal, semi-metal, ceramic, glass, plastic, or rubber, alloy, composite, agglomerate, or other organic. The organic selection should remain solid in handling and may become liquid during compaction. These materials may consist of a liquid, solid or mixture selected from the group consisting of fatty acids; and amides, bisamides, soaps and salts of fatty acids, waxes, resin, oils, hydrogenated fats and oils, polymers, mold release or friction reducing agent. With lubricity enough to enable ejection of a molded compact, flow and adequately low molecular weight and formulation to enable clean burn off if desired. With inputs that may include either pressure, solvents, chemical activation of polymers, or thermal heat; and working so as to enhance the gluing of particulates together and rounding of the agglomerate to provide flowability.
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FIELD OF THE INVENTION
The present invention concerns improvements in or relating to soil displacement tools.
BACKGROUND ART
Existing soil displacement tools are normally provided to carry out relatively small diameter tunneling or piling operations. They are pneumatically driven and comprise an elongate member incorporating a cylinder arranged with its axis coincident with the longitudinal axis of the tool, a piston being caused to reciprocate and, in normal operation, strike an anvil plate at the forward end of the tool to cause the tool to move through the soil in which it is placed as a result of the impact imparted to the tool by the piston.
Such tools are wasteful in energy in that the compressed air which is fed thereto is exhausted to atmosphere from the rear of the tool. Additionally, they are relatively low on power.
They suffer from the further disadvantage that they are on many occasions lost as a result of being trapped down the hole they have produced as a result for example, of collapse of the hole behind the tool. This problem is mitigated in certain tools by providing a reversing action so that the piston is caused to impact the rear end of the tool to cause it to move in a reverse direction but this has called for relatively complicated and expensive valve gear and has not been particularly efficient.
A further disadvantage which often occurs in a piling operation is that as the tool is withdrawn from the hole it has produced the hole collapses prior to the introduction of a cementitious grout which is to be fed into the hole to produce the pile.
SUMMARY OF THE INVENTION
It is an object of the present invention to obviate or mitigate these disadvantages.
According to the present invention there is provided a soil displacement tool comprising an elongate body having a cylinder formed therein, a piston movable in the cylinder, hydraulic liquid supply and exhaust lines to the cylinder and valve means for causing the piston to selectively impact one or other end of the cylinder to move the tool.
Preferably the piston and cylinder are annular so that a central longitudinal passage may be provided through the tool.
Preferably a supply line may be connected to said central passage so that material, for example cementitious grout, may be passed through the tool as it is being withdrawn from the hole it has produced.
Preferably the valve means for reversing the action of the piston are provided on the tool, said means being actuated by a cable extending from the rear of the tool. Alternatively, reversal of the piston may be caused by the changeover of the hydraulic liquid supply and exhaust to and from the tool, remote from the tool.
Preferably a removable end cap is provided at the leading end of the tool to close off the central passage as the tool progresses, the end cap being "lost" as the tool is withdrawn. Alternatively, a one-way valve may be provided at the end of the passage.
In certain instances it may be desirable to provide a withdrawal cable extending from the rear end of the tool.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:
FIG. 1 shows a side elevation of a hydraulically powered soil displacement tool or mole according to the present invention; and
FIG. 2 is a partial side elevation of an alternative embodiment thereof.
DETAILED DESCRIPTION
The tool comprises a cylindrical casing 10, the forward end 12 of which is provided with stepped protrusions 14 the diameter of which reduce towards the leading end of the tool. A removable end cap 16 is fitted over the leading protrusion 14 and covers a circular cross-section passage 18 which extends through the centre of the casing 10 from the forward to the rearward end, a connection 20 being provided at the rearward end of the tool for a flexible supply line 22.
An annular cylinder 24 is formed within the casing 10 terminating at each end in forward and rearward striking plates or anvils 26, 28 adapted in use to be impacted by a reciprocable annular piston 30 provided with standard sealing rings (not shown) in the cylinder 24.
An hydraulic liquid supply line 32 leads to a connection 34 at the rearward end of the casing and, in a similar manner, an exhaust line 38 is connected to the rearward end of the casing 10 by a connection 36.
Valve gear and fluid lines, which do not form part of the present invention and consequently will not be described, are provided in the casing so that, in action, when a pressurised hydraulic fluid is supplied to the cylinder by way of the valve gear and internal lines through the supply line 32 the piston 30 is caused to reciprocate in the cylinder 24. In normal operating conditions the energy of reciprocation towards the leading end 12 of the casing is greater than the energy of return, so that impact of the cylinder 30 against the forward striking anvil 26 causes the tool to be driven through soil in which it is placed in a forward direction. The driving effect is achieved by a spring urged forward head 27 slidably mounted on the casing 10.
Preferably the valve gear in the casing incorporates reversing means whereby the piston can be caused to move towards the rear of the casing at a greater energy than its return towards the leading end of the casing so that the piston 30 impacts against the rear impact anvil 28 to cause reverse movement of the tool. This reversing valve gear may be controlled by a control cable 40 or a further hydraulic line leading from the rear of the casing. A shackle 42 may also be provided on the rear of the casing to facilitate rearward movement of the tool by a heavy duty cable 50 attached thereto.
The tool of the present invention is particularly advantageous in a piling operation where it is driven vertically into the ground or at an angle close to the vertical in a location where a pile has to be formed and when the tool has reached the desired depth it is withdrawn from the hole either by reversing the hydraulic supply thereto or by withdrawing it with the aid of a heavy duty cable. As the tool is withdrawn comentitious grout can be supplied under pressure through the flexible supply line 22 and the central passage 18 to fill the void left as the tool is withdrawn and thereby form the pile.
It will be realised, of course, that the hollow nature of the tool makes it suitable for other operations, for example for pulling cables through soil etc.
A further advantage of the machine is that the resistance to movement of the tool through the soil is in relationship to the pressure and volume of the hydraulic fluid supply to the tool to cause this movement. It is a relatively simple matter to monitor these pressure and volume conditions and to calculate a direct reading, at the surface, of the resistance being experienced by the tool and consequently the load which the pile provided in the soil to this depth will support.
Various modifications can be made without departing from the scope of the invention. For example, the removable end cap 16 can be replaced by a one-way valve 54, shown in the partial side elevation in the alternative embodiment of FIG. 2. The configuration of the cylinder, piston, striking plates, etc. can be modified and the hydraulic supply can be arranged in any desirable manner, for example, so that movement reversal can be achieved by reversing, at the surface, the hydraulic supply and exhaust to and from the tool.
In a modification the tool need not have a central passage, in which case the piston and cylinder will be circular in cross-section. The tool, as outlined above, can be used for piling operations in many different modes. For example it may provide the unlined passage for the pile in the manner described or a lined passage by pulling down with it pile casings, the tool being located in the forward interior end of the casing. Alternatively it may provide a lined pile by driving pile sections from above ground level. The piles may be vertical or angled.
The tool may also be used to drive small diameter horizontal or inclined tunnels and may be utilised to pull pipes behind it. It may be used to brake up existing pipes.
Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to whether or not particular emphasis has been placed thereon.
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A soil displacement tool, or mole, comprises a hollow cylindrical body in which is provided an hydraulically reciprocal piston the movement of which drives the tool through the soil to form a hole, the body and piston being annular such that the tool is hollow.
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BACKGROUND OF THE INVENTION
Pneumatic impact mechanisms typically employ a reciprocating piston which is accelerated in one direction by means of alternately applied air pressure. The piston, upon striking its intended anvil (usually a chisel or the like), rebounds in the opposite direction and the process is repeated. Typically in pneumatic tools a bridge or stop is incorporated in the tool barrel to ensure that the piston will not be propelled out of the tool accidentally in the event the chisel is removed. In addition, when the tool is operated in the play-off mode with a long travel retainer (for example, when a typical pneumatic impact tool, such as a chipper) is removed from the work, the chisel moves forward allowing the piston to travel past the design strike point and to hit the retaining bridge.
Repeated hitting of the bridge creates high vibration levels and leads to eventual tool failure. To prevent the piston from striking the bridge, it is common to utilize an air cushion which is formed when the forward motion of the piston takes it past the strike point. The piston is stopped gradually in this manner without hitting the bridge.
Air cushions have been used on light duty pneumatic tools, such as scalers, and in heavy duty tools, such as rock drills. The formation of a successful air cushion requires tight fits between the piston diameters and the barrel bores and tight concentricity tolerances on barrel bores. These tight tolerances are difficult to hold, expensive to produce, and increase the rejection rate.
The present invention allows the use of conventional barrels with little modification and provides the required sealing for an effective air cushion.
It is an object of this invention to provide an air cushion seal which is self-aligning, inexpensive to manufacture, and effective without the need for tight concentricity sealing tolerances.
These and other objects are obtained in an air cushion seal for pneumatic impact tools having a reciprocating piston with a cushion end disposed in a barrel cylinder having a bridge for retaining the piston at one end comprising: a seal bushing disposed in close fitting concentric relationship with the cushion end of the piston when the piston approaches the bridge; the seal bushing being further disposed in concentric relationship with the barrel cylinder at the bridge and having minimum but appreciable radial clearance so as to allow the seal bushing to align itself with the cushion end of the piston while providing a substantially restricted diametral flow path of substantially increased length passed the bridge.
BRIEF DESCRIPTION OF THE DRAWINGS
The FIGURE shows a cross section of a portion of a pneumatic chipper showing the air cushion construction according to this invention.
DESCRIPTION OF THE INVENTION
The FIGURE shows the end portion of a typical pneumatic chipper. A generally cylindrical barrel 5 encloses a cylinder 11, which houses a reciprocating cylindrical piston 6. The piston 6 is formed with a reduced diameter portion 10 towards its one end. The reduced diameter portion 10 forms a land 12 which coacts with a bridge 2 formed in the barrel to prevent the piston from being accidentally propelled from the tool towards its one end or to the left as viewed in the FIGURE.
Also shown inserted in an axially aligned, but separate, bore 15 in the barrel is a cylindrical guide bushing 9. Shown inserted in the guide bushing 9 is a chisel 1. Only the back end of the chisel is shown. The retainer and chisel point construction are conventional and are not a consideration in the present invention. A floating seal bushing 3 is provided to form a seal between the reduced diameter portion of piston 10, the bridge 2, and a counterbored end portion 14 of the guide bushing 9. The floating seal bushing is the core of the present invention.
As previously described, it is important for tool life and noise reduction to prevent the land 12 of the piston 6 from striking the bridge 2. In normal operation, the chisel 1 would be inserted to the design strike point line, designated by the reference numeral 7, and the piston 6 would impact on the chisel producing the desired results. In this case an air cushion is not formed or desirable. However when the chisel is partially removed; for example, to the play-off position as shown in the FIGURE, the piston can travel far enough forward to have land 12 strike the bridge thereby producing noise, vibration, and possibly damage to the tool.
To prevent this, a trapped annular air volume 8 is formed in the reduced diameter portion area of the piston between the piston land 12, the reduced diameter of the piston, the barrel and the bridge. It can be appreciated by one skilled in the art that as the piston 6 moves to the left as shown in FIG. 1, the volume of air trapped in the annular air volume 8 is reduced, and if properly sealed, the pressure in the air volume 8 will increase to stop the piston travel.
It will also be appreciated by one skilled in the art that the degree of sealing depends on the tolerance maintained between the outside diameter of the piston 6 and the inside diameter of the cylinder bore 11. The degree of sealing is also dependent on the seal developed between the reduced diameter portion 10 of the piston and the bridge.
The difficulty of maintaining concentric tolerances has been overcome by the use of the floating seal bushing 3 according to the present invention. Because of the self-aligning feature of the floating seal bushing 3, tight tolerances may be maintained between the reduced diameter portion 10 of the piston and the inside diameter of the floating seal bushing 3. The outside diameter of the floating seal bushing forms a labyrinth-type seal between the bushing and the bridge and guide bushing.
In addition, as the air pressure increases in the trapped annular air volume 8, the floating seal bushing 3 will be forced to the left as shown in the FIGURE by the differential air pressure. This will force the floating seal bushing 3 to seat against the bottom of counter bore 14, thus further increasing the seal effectiveness. The leakage around the outside of the guide bushing 9 may be kept to a minimum by use of a close tolerance fit or other suitable seal.
In the above-described embodiment, all of the components are cylindrical or circular in cross section to facilitate manufacture. They, of course, could be square or other shape without departing from the spirit of the invention. The seal bushing may be contructed of steel, bronze, plastic, or similar materials. These and other modifications will occur to one skilled in the art.
We do not wish to be limited in the scope of our invention except as claimed in the following claims.
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The invention disclosed comprises an air cushion system that utilizes a two-diameter piston and a floating bushing to create an effective air cushion seal which prevents the piston from hitting the barrel bridge.
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DESCRIPTION
1. Technical Field
This invention is in the field of pressure containing valve shells for large aperture swing plate valves, which are used for the diversion of gas flows in large volume.
2. Background of the Invention
Large aperture swing plate valves of the type involved in the present invention comprise a main inert conduit connected to two branching (outlet) conduits which diverge from the main conduit in the form of an inverted "Y". A swing plate is mounted internally of the conduits at their intersection. This plate may be swung between two opposed positions, to alternatively cover or uncover parts leading to the branch conduits and thus divert the gas flow from the main conduit into one or the other of the branch conduits as desired.
The exterior contour of these large aperture swing plate valves is generally cylindrical at the main entrance conduit end and generally elliptical at the branching conduit (outlet) ends, due to the side by side arrangement of the branching conduits.
A shell of the type previously used for enclosing these valve is shown in FIG. 1 of the accompanying drawings. They are expensive to make and require stiffening ribs for strength and rigidity. The structure is so large, and the shape so unusual, that the cost of manufacturing a swaged or forged shell has been prohibitive. Therefore the prior art shells have been constructed by welding together a number of rolled steel plates and ribs of various shapes, as shown in FIG. 1, even though a swaged or forged shell would have been preferable and a method been available for manufacturing such a shell at a reasonable cost.
SUMMARY OF THE INVENTION
According to the present invention, a manufacturing method for a forged or swaged shell for a large aperture swing plate valve is provided at a low cost of manufacture, thereby making it commercially feasible to utilize forged or swaged ferrous metal for such shells.
The manufacturing method of the present invention enables the blank or stock from which the shell is to be made to be a standard commercially available pressure vessel head. Such heads are manufactured and sold in relatively large quantities at a relatively low cost. They normally are used commercially as the end; or ends, of large ferrous pressure vessels such as shown in FIG. 4 of the accompanying drawings. These heads are strong and rigid and have the properties and characteristics necessary for swing plate valve shells. However, their form and shape is not that required for such rise, and their reforging to such shape would be impractical because of the prohibitive costs involved.
By the present invention a method is provided whereby such pressure heads can be changed from their original shape to one that is highly suitable for use as a swing plate valve shell, at a very low cost and without re-forging or reforming the metal of the pressure heads in any way. All that is required according to the present invention is to make a single cut through a standard pressure head at a particular location to form two halves, then to rotate each half to a particular position relative to the other half as hereinafter described, and then to weld together the repositioned halves in their new location relative to each other. The method is simple when looked at by hindsight; yet for the first time makes commercially feasible, the manufacture of forged or swaged ferrous metal shells for large aperture swing plate valves.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the flat plate swing valve shell of the prior art including the lower outlet ports and upper inlet port;
FIGS. 2 & 3 show, respectively, a vertical cross-section and a plan view of the dish-shaped pressure vessel head to construct the plate swing valve shell of the present invention;
FIG. 3A shows a dish-shaped pressure vessel head of slightly modified shape, which also can be used to make swing plate valve shells by the method of the invention;
FIG. 4 shows the pressure vessel head of FIGS. 2 and 3 as normally used, in place on a pressurized tank shown in phantom;
FIG. 5 shows the step of cutting the pressure vessel into two sections;
FIG. 6 shows the two sections of the pressure vessel head being rotated and rearranged;
FIG. 7 shows the resultant configuration after the two sections have been rearranged;
FIG. 8 shows the pressure vessel head now rearranged to form the plate swing valve shell, having been welded along the seam;
FIG. 9 shows the newly formed plate swing valve shell having an upper opening cut therethrough; and
FIG. 10 shows the completed swing plate valve shell positioned in place over the swing plate valve base, and showing the upper inlet conduit and the lower branching conduits (outlets) protruding therefrom.
BEST MODE FOR CARRYING OUT THE INVENTION
Referring to FIG. 1, the plate swing valve 1 of the prior art, is shown having an upper inlet port 2 and a pair of lower outlet ports 3 and 4. The upper portion of the valve 1 is generally conical, having a wide lower end, adjacent the pair of outlet ports 3 and 4, and tapering to an upper portion adjacent the inlet port, where it is truncated.
Prior art plate swing valve 1 is constructed of flat plate steel, typically SA 515 grade 60, which is cut, rolled and formed into a variety of shaped sections. The sections are welded together to form the valve shown in FIG. 1.
In forming a plate swing valve by the above procedure, the geometry results in stress raisers which cause the valve to be weak and susceptible to rupture. In order to prevent distortion, the prior art valves included stiffeners 5 at the flat surface. These stiffeners 5 enable the valve to maintain its rigidity when the internal pressure increases.
The cylindrical and conical portions of the prior art valve shell are formed of curved strips 6 of steel which are cut and rolled. The front and back faces 5a of the valve remain flat. A horizontal cross-section would be roughly elliptical having flat sides along its major axis. These flat sides must be supported by additional stiffeners to prevent the flat sides from "bowing" from within.
The present invention provides swing plate valve shells that can be constructed from pressure vessel heads made from ferrous metal forgings which are available as standard articles of commerce, and which according to the method of the invention can be made into unitary shells providing the benefits of forged ferrous metal and obviating the disadvantages of welded and rolled plates and rib construction.
FIGS. 2 and 3 each show a pressure vessel head which is used to cap the end of a variety of pressurized cylindrical vessels such as that shown in FIG. 4 of the drawings. These are commercially available at a fraction of the cost of constructing swing plate valve shells of the prior art, as shown in FIG. 1.
Heads of this type shown in FIGS. 2 and 3 are normally available in two shapes. FIG. 2 shows a generally spheroidal dish-shaped head having circular horizontal cross-sections with an outer diameter shown as D in FIG. 2. Vertical cross-sections are elliptic. The diameter D of the dish-shaped head is used to define the shape of the dome of the head.
The dome of the head, as shown by the cross-section of FIG. 2 is defined by a pair of circles. The first circle (from Point A to Point B) can be defined by the general formula for a circle; and point (x,y,) along the circumference being equidistant from its center by a radius "r", where r is the radius of the circle and 2r is the diameter.
The first circle is formed so that its diameter (2r) would be 80% of the outer diameter (D) of the generally spheroidal head.
The second circle (from Points A to A' and B to B') are defined by the radius "r'", where r' is the radius of the circle and 2r' is the diameter.
The circle defined by the radius r' is formed so that the diameter 2r' is 10% of the outer diameter D of the spherical head. This creates a head having a gradual curve at its upper portion; and a sharper curve at its edges. Below the second circle the lower end of the head is formed by an annular cylindrical ring section so that the lower end is virtually straight. Pressure heads of this type are commonly referred to in the art as "80-10 heads".
Other pressure heads also commercially available which can be employed in the present invention are "100-6 heads", where the large circular section has a diameter equal to that of the head, and the smaller circular sections have a diameter of 5% of that of the head.
FIG. 3A shows a second dish-shaped head having an elliptical vertical cross-section and a circular horizontal cross-section. The first dome-section (from Points C to D) of the vertical cross-section is defined by the general formula for ellipse:
(X.sup.2 /a.sup.2)+(y.sup.2 /b.sup.2)=C
where points having coordinate (x,y) form a perimeter of the ellipse having a major axis of a and a minor axis of b.
The second dome-section, from C and D to the bottom as seen in FIG. 3A is formed by an annular cylindrical ring section. Thus the head is elliptical at its upper end and virtually straight along its lower sides.
Any of the above described pressure vessel heads can be used to form the plate swing valve shell of the present invention.
In order to conform the pressure vessel head of FIGS. 2 or 3A to the shape desired for use as a flat plate swing valve shell; the head is cut and then the sections are rearranged.
FIG. 5 shows the first step of the precess, whereby a diametrical cut is made through the head dividing it into two substantially equivalent sections 51 and 52. This cut can be accomplished by any means which would yield a clean cut. For example, an oxy-acetylene cutting torch may be used.
The two halves are then rotated as shown in FIG. 6 through a 90° angle about an axis that is formed by the intersection of the vertical plane through which the cut is made and the horizontal plane of the base. The halves of the semicircular outer rim 61a and 61b now meet at junction 61 and a new outer rim or base 62 is formed by the rim 62a and 62b formed along each side of the diametrical cut.
A seam 61 is created by the junction of the outer rim 61a and 61b.
FIG. 7 shows the two sections put back together in a new arrangement so that it has an opening which is roughly elliptical, formed by new outer rim 62.
The two rearranged sections are then welded together along the weld seam 81 shown in FIG. 8.
In order to allow the gas to pass through the valve a centrally located entry opening 90, (see FIG. 9) is cut through the dome. A cylindrical conduit 92 (see in FIG. 10) is attached adjacent to and extending up from entry opening 90 to form an inlet port 95 for the inflow of gas.
FIG. 10 shows the complete arrangements of the plate swing valve 100 of the present invention. The shell and its outer surface is smooth and rounded. No stiffening ribs, or other stress raisers, are necessary or present.
The resultant plate swing valve 100, will have a horizontal cross-section which is roughly elliptical. This elliptical cross-section eliminates the parallel flat faces that are present in the prior art plate swing valves (see FIG. 1). The rounded front faces of plate swing valve 100 allow it to withstand a higher degree of internal pressure and temperature than was possible with the prior art valve.
The bottom base plate is welded in place, around the two downwardly branched (outlets) to form a complete gas-tight pressure containing enclosure or shell for the flat plate swing valve.
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A method of forming a flat plate swing valve shell from a commercially available forged or swaged pressure vessel head having circular sections in horizontal planes and elliptic sections in vertical planes. The shell is formed by cutting the head along a vertical axis to form two halves, rotating the halves outwardly with respect to each other and repositioning them so their original base edges are juxtaposed and the two halves form a continuous enclosure having an open base and which has elliptic sections in both vertical and horizontal planes, and welding the two halves along said base edges to form a unitary valve shell.
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BACKGROUND
Log cabins utilize a primitive form of construction which has been used by persons in this and foreign countries for many years. Some of the drawbacks to current use of traditional log cabin construction are the expense and difficulty of obtaining logs of uniform size, the difficulty of insulating the structure, and the lack of room within the walls for electrical wiring. Nevertheless there is a continuing public desire for buildings having the appearance of traditional log cabins. As a result of these shortcomings, there is a need for means and methods of creating structures which, while having conventional building construction, create the desired appearance of log cabins.
Earlier designs have attempted to give the appearance of log cabin construction while not using full logs. However, these earlier designs have resorted either to partial corner construction or to complex end-piece configuration to accomplish the desired result. The partial corner construction of the prior art does not give a realistic appearance of traditional mortise log cabin construction. Further, the complex end-piece configurations of the prior art is much more complex to manufacture and is not readily adapted to speedy field construction with a minimum of tools. Thus there is a need for full corner log siding in which all pieces can be pre-formed, leaving only straight saw cuts to be made in the field.
My invention is directed to the use of wood products to fabricate log siding and corner pieces which are used in cooperation with each other to make any new or existing construction look exactly as if it has been built as traditional mortise log cabin construction.
This invention provides partial-log-shaped wood siding which can be made from standard rough cut material such as 2-inch or 3-inch boards, thus being cost competitive with other standard sidings. The use of standard rough cut material substantially reduces waste and cost. The corner pieces of this invention are pre-cut from full logs; half of the corner pieces are cut as tabbed corner pieces and half of them are cut as pointed corner pieces. The siding is erected from prefabricated pieces cut to shape to abut against the shape of the prefabricated corner pieces. No cutting tools beyond a standard circular saw are needed in the field.
My invention also provides corners of full log construction which give the entire structure a look identical to that of a traditional log cabin. The corners are constructed of prefabricated pieces which fit together without adjustment in the field. Additionally, the corner pieces are small enough that they can easily be kiln dried prior to use, thus eliminating future shrinkage and preventing the formation of gaps which require caulking.
My invention can be used on any new or existing building which has an adequate roof overhang. It provides the look of traditional log construction at greatly reduced cost; the reduced weight of this full corner log siding also reduces the costs of shipping from the factory to the building site.
My full corner log siding provides log siding and corner pieces cooperating with the siding for use on a typical structure having a foundation and four or more walls, where the walls meet perpendicularly at four or more intersecting corners, and the four or more walls rest on the foundation. The log siding is comprised of rows, a first row to abut the foundation and additional rows to extend upward therefrom. Each of the rows has one straight end and one fitted end. Each of the rows has one or more pieces.
Each of the row pieces is formed as a cylindrical segment of a pre-determined radius having width, a height, a length, a top extension, a bottom recess, an inner face along the chord of the cylindrical segment, and an imaginary center plane along the length of the piece and perpendicular to the inner face. The inner face of each piece is made to abut and be fastened to one of the four or more walls, the bottom recess of each piece of the first row to abut the foundation of the structure, and the bottom recess of each piece of every row other than the first row to overlap the top extension of the next lower piece. The straight end of each row is a piece with ends substantially perpendicular to the length of the piece.
The fitted end of each row is a piece having an inner end and a pointed end; the inner end is a surface perpendicular to the length of the piece, and the pointed end comprises two concave cylindrical surfaces, an upper concave cylindrical surface and a lower concave cylindrical surface, the radius of each of said upper and lower concave cylindrical surfaces being equal to the radius of the piece, with each of the upper and lower concave cylindrical surfaces having a height of half the height of the piece and a maximum width of the width of the piece, and with the upper concave cylindrical surface being perpendicular to the top of the cylindrical segment and the lower concave cylindrical surface being perpendicular to the bottom of the cylindrical segment; the upper and lower concave cylindrical surfaces form an apex at the imaginary center plane of the piece. Each of the fitted end pieces is made to abut and be fastened to one of the four or more walls.
Each of the corner pieces is a substantially cylindrical log of the same radius as that of the siding pieces, having an imaginary center plane along its length, said imaginary center plane being substantially horizontal, and having a top plane along a chord of the log at a distance of half the height of the siding pieces above the imaginary center plane, the top plane being substantially horizontal and having a length parallel to the length of the corner piece and having a width perpendicular to the length of the corner piece, and having a bottom plane parallel to the top plane at a distance of half the height of the siding pieces below the imaginary center plane, the bottom plane being substantially horizontal and having a length parallel to the length of the corner piece and having a width perpendicular to the length of the corner piece.
The bottom plane of the first corner piece is made to abut the foundation of the structure and the bottom plane of each corner piece other than the first corner piece is made to abut the top plane of the next lower corner piece.
Each of the corner pieces is made to extend outwardly from one of the four or more intersecting corners of the structure in either a first direction or a second direction, the first direction to extend the line of one of the walls and the second direction to be perpendicular to the first direction.
The corner pieces are either tabbed corner pieces or pointed corner pieces. Each of the tabbed corner pieces has a top plane, a bottom plane, a distal face, an inner end, a length between the distal face and the inner end, an exterior convex surface to form a 180-degree angle with an adjacent wall, and an interior convex surface to form a 90-degree angle with a second, adjacent, wall. The distal face is substantially perpendicular to the length of the tabbed corner piece. The inner end has three planes, a first plane, a second plane, and a third plane; the first plane is perpendicular to the length of the tabbed corner piece and is a circular segment of the same radius as that of the siding pieces, having width equal to that of the siding pieces, and having height equal to the height of the siding pieces; the second plane is a rectangle perpendicular to the first plane and has a width equal to the height of the siding pieces and a length less than the width of the top and bottom planes of the adjacent pointed corner pieces; and the third plane is perpendicular to the second plane. The distance between the distal face and the first plane of the inner end is greater than the distance between the distal face and the third plane of the inner end.
The interior convex surface of the tabbed corner piece is made to abut the upper concave cylindrical surface of the fitted end of one row and the lower concave cylindrical surface of the fitted end of the next higher row. The first plane of the inner end of the tabbed corner piece is made to abut the straight end of one row, the second plane of the inner end of the tabbed corner piece is made to abut one of the four or more walls at one of the four or more intersecting corners, the tabbed corner piece can be fastened to the first wall through the second plane, and the third plane of the inner end of the tabbed corner piece is made to abut the wall which intersects the one wall at that intersecting corner and the tabbed corner piece can be fastened to said intersecting wall through the third plane.
Each of the pointed corner pieces has a top plane, a bottom plane, a distal face, a pointed end, a length between the distal face and the pointed end, an exterior convex surface to form a 180-degree angle with an adjacent wall, and an interior convex surface to form a 90-degree angle with an adjacent wall. The distal face is substantially perpendicular to the length of the pointed corner piece. The pointed end comprises two concave cylindrical surfaces, an upper concave cylindrical surface and a lower concave cylindrical surface; the radius of each of the upper and lower concave cylindrical surfaces is equal to the radius of the pointed corner piece; each of the upper and lower concave cylindrical surfaces has a height equal to half the height of the siding pieces and a maximum width equal to the width of the pointed corner piece; the upper concave cylindrical surface is perpendicular to the top plane of the pointed corner piece, the lower concave cylindrical surface is perpendicular to the bottom plane of the pointed corner piece, the upper and lower concave cylindrical surfaces form an apex at the imaginary center plane of the pointed corner piece, and the lower concave cylindrical surface is made to abut the exterior convex surface of one of the tabbed corner pieces and its adjacent straight end piece and the upper concave cylindrical surface is made to abut the exterior convex surface of the next higher tabbed corner piece and its adjacent straight end piece, and the pointed corner piece can be fastened to the adjacent tabbed corner pieces and straight end pieces. The exterior convex surface of each of the pointed corner pieces extends the outer circumferential surface of a previously placed siding piece.
These and other features, aspects, and advantages of the invention will be become better understood with regard to the following description, appended claims, and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be further described in connection with the accompanying drawings, in which:
FIG. 1 is a perspective view of the log siding and cooperating corner pieces of the full corner log siding of a version of the invention.
FIG. 2 is a partial plan view of the log siding and cooperating corner pieces of FIG. 1.
FIG. 3 is an elevation view of the log siding and cooperating corner pieces of FIG. 1.
FIG. 4 is a perspective view of a typical siding piece of the log siding shown in FIG. 1.
FIG. 5 is a perspective view of a piece at the fitted end of a row of the log siding shown in FIG. 1.
FIG. 6 is an elevation view of the end of one of the corner pieces shown in FIG. 1.
FIG. 7 is a perspective view of one of the tabbed corner pieces shown in FIG. 1.
FIG. 8 is a perspective view of one of the pointed corner pieces shown in FIG. 1.
FIG. 9 is an elevation view of the end of a corner piece of an alternate embodiment of the invention using one spline and groove.
FIG. 10 is an elevation view of the end of a corner piece of an alternate embodiment of the invention using two splines and grooves.
FIG. 11 is an elevation view of the end of a corner piece of an alternate embodiment of the invention using circular tops and recessed bottom surfaces.
FIG. 12 is a perspective view of a tabbed corner piece in an alternate embodiment of the invention using circular tops and recessed bottom surfaces.
FIG. 13 is a perspective view of a pointed corner piece in an alternate embodiment of the invention using circular tops and recessed bottom surfaces.
DESCRIPTION
Elements of the Invention
Referring now to the drawings, wherein like reference numerals designate like or corresponding parts throughout the several views, FIG. 1 illustrates a preferred embodiment of the invention.
As shown in FIG. 1, my full corner log siding 10 can be used on a structure having a foundation 20 and walls 25 with intersecting corners 30. The log siding comprises pieces 40 which cooperate to form rows 50. The corner pieces 100 cooperate with the log siding 10 to create my full corner log siding. As shown in FIG. 1, the corner pieces 100 are comprised of tabbed corner pieces 200 and pointed corner pieces 300. The tabbed corner pieces 200 can be fastened to wall 25 by fasteners 400. Fasteners 400 are six point finishing screws with recessed heads or any other suitable fasteners such as nails, pins, pegs, or glue. The number of fasteners 400 needed will vary in relation to the size of the log siding used, and will be apparent to those skilled in the art.
My full corner log siding can be used with standard wall construction as shown in FIG. 2. As shown in FIG. 2, straight end piece 40 of row 50 is made to abut interior convex surface of tabbed corner piece 200. FIG. 2 also shows that the tabbed corner pieces 200 are made to enclose the intersecting corner 30, and the pointed corner pieces 300 are made to abut the exterior convex surfaces of tabbed corner piece 200 and straight end piece 40.
As shown in FIG. 3, the fitted ends 54 of rows 50 are shaped to conform to the interior convex surfaces 240 of tabbed corner pieces 200, and the faces of pointed corner pieces 300 are shaped to conform to the exterior convex surfaces 230 of tabbed corner pieces 200. Fasteners 400 are shown attaching pointed corner piece 300 to tabbed corner piece 200 and to straight end piece 40.
FIG. 4 depicts a typical siding piece 40, comprised of a cylindrical segment of pre-determined radius 42, width 43, height 44, and length 45. The siding pieces 40 can be economically produced using standard 2-inch or 3-inch thick lumber such as 2×6 or 3×8. The siding pieces 40 have a top extension 46, a bottom recess 48, an inner face 41 along the chord of the cylindrical segment, and an imaginary center plane 49 along the length 45 and perpendicular to the inner face 41.
When siding piece 40 is installed on wall 25, the bottom recess 48 of the first siding piece 40 abuts the foundation of the structure and the bottom recess 48 of each siding piece 40 other than the first siding piece is fitted over the top extension 46 of the next lower piece to create an overlapping joint. Every reference to siding piece 40 is also applicable to fitted end piece 54.
One end of each row 50 is comprised of a fitted end piece 54 which is preformed to abut against the outer circumference of the tabbed corner piece 200.
FIG. 5 depicts a typical fitted end piece 54. Each of the fitted end pieces 54 is comprised of a cylindrical segment of radius 42, having width 43, height 44, and length 45. The radius 42 of the fitted end pieces 54 is equal to the radius 42 of the siding pieces 40. Each of the fitted end pieces 54 has an inner end 55 and a pointed end. The pointed end is comprised of an upper concave cylindrical surface 56 and a lower concave cylindrical surface 57, wherein each of the upper and lower concave cylindrical surfaces 56 and 57 has a radius 42 equal to the radius 42 of the siding pieces 40, a height of half the height 44 of the siding pieces 40, and a maximum width equal to the width 43 of the siding pieces 40. The upper concave cylindrical surface 56 is perpendicular to the top of the cylindrical segment, the lower concave cylindrical surface 57 is perpendicular to the bottom of the cylindrical segment, and the upper and lower concave cylindrical surfaces 56 and 57 form an apex 58 at the imaginary center plane 49 of the fitted end piece 54. When fitted end piece 54 is installed on wall 25, bottom recess 48 of the first fitted end piece 54 abuts the foundation 20 of the structure and bottom recess 48 of each fitted end piece 54 other than the first one is fitted over top extension 46 of the next lower piece to create an overlapping joint. Each of the fitted end pieces 54 is made to abut and be fastened to one of the four or more walls 25.
As shown in FIG. 6, each of the corner pieces 100 is a substantially cylindrical log of radius 42. The radius 42 of the corner pieces is equal to the radius 42 of the siding pieces 40. The corner pieces 100 are preferably formed from wood logs. The corner pieces of the first version of my invention have a substantially horizontal top plane 104 along a chord of the substantially cylindrical log. The top plane 104 has a length parallel to the centerline of the corner piece and a width perpendicular to the length. The top plane 104 lies at a distance of one-half the height 44 of the siding pieces 40 and 54 above an imaginary center plane 102. The imaginary center plane 102 is substantially horizontal and passes through the centerline of the corner piece. The corner pieces also have bottom plane 106 parallel to the top plane 104 and at a distance of one-half the height 44 below the imaginary center plane 102. The bottom plane 106 has a length parallel to the centerline of the corner piece and a width perpendicular to the length. Every reference to corner piece 100 is equally applicable to tabbed corner pieces 200 and pointed corner pieces 300.
The bottom plane 106 of the first corner piece 100 is made to abut against the foundation 20 of the structure and the bottom plane 106 of each corner piece 100 other than the first corner piece is made to abut the top plane 104 of the next lower corner piece.
The corner pieces which are made to abut the intersecting corners 30 of the structure are tabbed corner pieces 200. A typical tabbed corner piece 200 is shown in FIG. 7. Each of the tabbed corner pieces 200 has a top plane 104, a bottom plane 106, a distal face 210, an inner end, a length 212 between the distal face and the inner end, an exterior convex surface 230, and an interior convex surface 240. The top plane 104 and the bottom plane 106 are substantially horizontal. The interior convex surface 240 is that which will form a 90-degree angle with adjacent wall 25 when the log siding is installed; the exterior convex surface 230 is that which will form a 180-degree angle with adjacent wall 25 when the log siding is installed. The distal face 210 is substantially perpendicular to the length 212 of the tabbed corner piece 200. The inner end has three planes, a first plane 224, a second plane 226, and a third plane 228. The first plane 224 is perpendicular to the length 212 of the tabbed corner piece 200 and is a circular segment of the same radius 42 as that of the siding pieces 40, having width 43 equal to that of the siding pieces 40, and height 44 equal to the height 44 of the siding pieces 40. The second plane 226 is a rectangle perpendicular to the first plane 224 which has a width 44 equal to the height 44 of the siding pieces and a length 227 less than the width of the top plane 104 and less than the width of the bottom plane 106 of the adjacent pointed corner pieces 300. The third plane 228 is perpendicular to the second plane 226. The length 212 between the distal face 210 and the first plane 224 of the inner end is greater than the distance between the distal face 210 and the third plane 228 of the inner end.
The interior convex surface 240 of the tabbed corner piece 200 is made to abut the upper concave cylindrical surface 56 of the fitted end 54 of one row 50 and the lower concave cylindrical surface 57 of the fitted end 54 of the next higher row 50. The first plane 224 of the inner end of the tabbed corner piece 200 is made to abut the end of one row 50, the second plane 226 of the inner end of the tabbed corner piece 200 is made to abut one of the four or more walls 25 at one of the four or more intersecting corners 30, the tabbed corner piece 200 can be fastened to the wall 25 through the second plane with fasteners 400, and the third plane 228 of the inner end of the tabbed corner piece 200 is made to abut the wall 25 which intersects the first wall 25 at that intersecting corner 30 and can also be fastened to said intersecting wall 25 with fasteners 400.
The pointed corner pieces 300 complete the full corner of my invention. A typical pointed corner piece 300 is shown in FIG. 8. Each of the pointed corner pieces 300 has a top plane 104, a bottom plane 106, a distal face 310, a pointed end, a length 312 between the distal face 310 and the pointed end, an exterior convex surface 330, and an interior convex surface 332. The interior convex surface 332 is that which will form a 90-degree angle with adjacent wall 25; the exterior convex surface 330 will extend the outer circumferential surface of a previously placed siding piece 40 on an intersecting wall 25, as shown in FIG. 1.
The distal face 310 is substantially perpendicular to the length 312 of the pointed corner piece 300. The pointed end is formed of two concave cylindrical surfaces, an upper concave cylindrical surface 322 and a lower concave cylindrical surface 324; the radius 42 of each of the upper and lower concave cylindrical surfaces 322 and 324 is equal to the radius 42 of the pointed corner piece 300; each of the upper and lower concave cylindrical surfaces 322 and 324 has a height equal to half the height 44 of the siding pieces 40 and a maximum width equal to the width of the imaginary center plane 102 of the pointed corner pieces 300; the upper concave cylindrical surface 322 is perpendicular to the top plane 104 of the pointed corner piece 300, the lower concave cylindrical surface 324 is perpendicular to the bottom plane 106 of the pointed corner piece, and the upper and lower concave cylindrical surfaces 322 and 324 form an apex 326 at the imaginary center plane 102 of the pointed corner piece 300. The lower concave cylindrical surface 324 is made to abut the exterior convex surface 230 of one of the tabbed corner pieces 200 and the upper concave cylindrical surface 322 is made to abut the exterior convex surface 230 of the next higher tabbed corner piece 200. The pointed corner piece 300 can be fastened to the adjacent tabbed corner piece 200 and siding piece 40 by fasteners 400.
Alternate embodiments of the corner pieces 100 of my invention are shown in FIGS. 9, 10, and 11. FIG. 9 depicts the use of a spline 110 extending upward from the top plane 104 and running the length of the top plane, and the use of a matching groove 112 extending inward from the bottom plane 106 and running the length of the bottom plane. The spline 110 is made of any convenient shape and size which will fit into the groove 112 to facilitate accurate placement of the corner pieces 100. Two or more splines 110 and grooves 112 may be used, as shown in FIG. 10. When two or more splines and grooves are used, the grooves 112 conform to the spacing, size and shape of the splines 110.
FIG. 11 depicts an alternate embodiment of the corner pieces 100 in which a convex cylindrical top surface 114 replaces the top plane 104 and a convex cylindrical bottom surface 116 replaces the bottom plane 106. Convex cylindrical top surface 114 is a continuation of the circumference of the substantially cylindrical log. Concave cylindrical bottom surface 116 has a radius 42, the same radius as that of the corner piece 100, the centerline of said concave cylindrical surface located along a plane which lies parallel to and at the height 44 of a siding piece 40 below the imaginary center plane 102 of the corner piece 100, as shown in FIG. 11.
The siding pieces 40, the fitted end pieces 54, the tabbed corner pieces 200, and the pointed corner pieces 300 are prefabricated away from the building site. If the first version of my invention is used, each of the components other than the fitted end pieces 54 can be used for either right-hand or left-hand construction, right-hand construction being designated as that in which the fitted end pieces 54 are placed at the right end of each row 50 on each wall 25. Right-hand construction is shown in FIG. 1. Fitted end pieces 54 can be prefabricated for right-hand construction so that each of them has its upper and lower concave cylindrical surfaces 56 and 57 at the right end of the piece when the top extension 46 is at the top of the piece.
If alternate embodiment corner pieces 100 are used, they can be prefabricated in either right-hand or left-hand construction according to the above nomenclature. Any one construction project will use only one method of construction, either right-hand or left-hand. Economy can be realized by prefabricating all pieces to fit one or the other of the construction directions; I have fabricated components for right-hand construction but left-hand construction would work equally well.
Although 2×6 and 3×8 lumber has been suggested as the basis for fabrication of siding pieces 40, it is recognized that many other sizes of lumber would also meet the requirements of my invention; the siding can be made to simulate nearly any dimension round log. The corner pieces 100 of my invention will be small enough so that they can easily be kiln dried prior to use, thus eliminating shrinkage after construction and preventing the formation of gaps which would require caulking.
Erection of the siding at the site requires the use of only a saw to make straight cuts and means such as screws, nails, pins, pegs, or glue to fasten the siding and corner pieces to the structure.
Use of the Invention
In erecting the siding of this invention, the builder will follow these steps. A first tabbed corner piece 200 is placed at the foundation 20 of a first wall 25 at a first intersecting corner 30 with a second wall 25 and fastened to the walls 25 by the use of fasteners 400 passing through the second plane 226 and through the third plane 228 of the tabbed corner piece 200. Next, a tabbed corner piece 200 is split longitudinally; one of the split tabbed corner pieces is then placed at the foundation 20 of the second wall 25 at a second intersecting corner 30 with a third wall 25 and fastened to both walls 25 by the use of fasteners 400 passing through the second plane 226 and the third plane 228 of the split tabbed corner piece 200.
Then another first tabbed corner piece 200 is placed at the foundation 20 of the third wall 25 at the third intersecting corner 30 with a fourth wall 25 and fastened to the walls 25 with fasteners 400; then another tabbed corner piece 200 is split longitudinally, and one of the split tabbed corner pieces is placed at the foundation 20 of the fourth wall 25 at the fourth intersecting corner 30 with the first wall 25, and is fastened to the walls 25 with fasteners 400. If there are additional walls and intersecting corners, first tabbed corner pieces 200 are fastened to the walls 25 at the intersecting corners 30 as above until there is one tabbed corner piece 200 at the foundation 20 of each intersecting corner 30.
Then tabbed corner pieces 200 are stacked on top of the first tabbed corner piece at each intersecting corner until the stacked tabbed corner pieces 200 reach the top of each wall; each tabbed corner piece 200 is fastened to each wall 25 with fasteners 400.
Next, the siding pieces are installed on the first wall. The siding can either be installed from the top down, or from the bottom up. Horizontal siding, where an overlap is involved as illustrated here, is generally installed from the botom up; this method will be described here. The first row 50 of siding is installed by first placing a fitted end piece 54 adjacent to and abutting the foundation of the first wall 25 and adjacent to the first tabbed corner pieces 200 so that the apex 58 of the fitted end piece 54 meets the junction between the first tabbed corner piece 200 and the next highest tabbed corner piece 200. Then the first row 50 is completed by placing pieces 40 adjacent to and abutting the foundation of the wall 25 to fill the space between the straight end of the fitted end piece 54 and the first plane 224 of the inner end of the tabbed corner piece 200 at the next intersecting corner 30. Each of the pieces 40 and 54 is fastened to the wall 25 by fasteners 400.
Then the second row 50 of siding is installed on the first wall 25 by fitting the bottom recesses 48 of the upper pieces over the top extensions 46 of the first row pieces and following the procedure used for installing the first row, and all remaining rows 50 are installed by continuing as for the second row. Each of the pieces 40 and 54 is fastened to the wall 25 by fasteners 400.
Then the siding is installed on the second wall 25. To make the first row 50, a fitted end piece 54 is split longitudinally and one of the split pieces is placed adjacent to and abutting the foundation 20 of the wall 25, and adjacent to the first tabbed corner piece 200 so that the apex 58 of the fitted end piece 54 meets the junction between the first tabbed corner piece and the foundation 20. Then the first row 50 is completed by splitting straight end pieces 40 and placing them adjacent to and abutting the foundation 20 of the second wall 25 to fill the length between the straight end of the fitted end piece 54 and the first plane 224 of the inner end of the tabbed corner piece 200 at the next intersecting corner 30. Each of the split pieces 40 and 54 is fastened to the wall 25 by fasteners 400.
Then the second row 50 of siding is installed on the second wall 25 by fitting the bottom recess 48 of each of the pieces of the second row over the top extension 46 of each of the pieces of the first row and following the procedure used for installing the first row, and all remaining rows 50 are installed by continuing as for the second row. Each of the pieces 40 and 54 is fastened to the wall 25 by fasteners 400.
The siding is installed on all remaining walls by following the procedures used on the first two walls, alternating walls on which the bottom row of siding is formed of longitudinally split pieces.
Lastly, the pointed corner pieces 300 are installed. At the first intersecting corner 30, a pointed corner piece 300 is split longitudinally and one of the split pointed corner pieces is placed adjacent to and abutting the foundation 20 of the second wall 25 at the first intersecting corner 30 so that the apex 326 of said split pointed corner piece 300 meets the junction between the first tabbed corner piece 200 and the foundation 20. Then the split pointed corner piece 300 is fastened to the first tabbed corner piece 200 and adjacent first siding piece 40 with fasteners 400. Caulking will be used by those skilled in the art during installation of the pointed corner pieces 300 to minimize moisture contact with the inner faces 322 and 324 of the corner pieces 300. The exterior convex surface 330 of each of the pointed corner pieces 300 extends the outer circumferential surface of a previously placed siding piece 40.
Then a pointed corner piece 300 is installed at the foundation 20 of the third wall 25 at the second intersecting corner 30 so that the apex 326 of the pointed corner piece 300 meets the junction between the first tabbed corner piece and the next highest tabbed corner piece 200 and fastening said pointed corner piece 300 to each of the adjacent tabbed corner pieces 200 and straight end pieces 40 with fasteners 400 as necessary.
Then the placement of the first row of pointed corner pieces is completed by placing pointed corner pieces 300 at the foundation 20 of all remaining walls 25 according to the procedures used at the first and second intersecting corners 30.
Finally, pointed corner pieces 300 are stacked on top of the first pointed corner piece at each intersecting corner 30 until the stacked pointed corner pieces 300 reach the top of each wall 25; each pointed corner piece 300 is fastened to each tabbed corner piece 200 and straight end piece 40 with fasteners 400 as necessary.
Advantages of the Invention
My invention has provided a means for fabricating and erecting building siding which has the look of traditional log construction without the cost or drawbacks of using full logs. Fabrication of the detached log ends is simpler than detached log end systems of "same look" siding. My left hand or right hand system reduces the number of pointed end siding pieces needed on a project by fifty percent over other systems. My log siding gives the look of traditional log construction on any new or existing building. Dimensions of the logs used are small enough that the wood can be kiln dried prior to construction, reducing shrinkage and making the wood lighter and easier to handle than convention "half log" siding, and leading to lower shipping and installation costs.
Caulking will be used by those skilled in the art during installation of the corner pieces to minimize moisture contact with the inner faces of the corner pieces.
The siding can be installed with an ordinary circular saw; no special tools are required for use in the field. The siding and corner pieces can be fabricated in any woodworking plant. The corner pieces can be manufactured from pieces that are presently considered waste at most log mills.
If corner pieces with splines 110 and grooves 112 are used, accurate placement of corner pieces 100 on top of each other is made easier and quicker. If corner pieces with circular tops 114 and recessed bottom surfaces 116 are used, a smoother and more aesthetically pleasing finished corner is obtained.
My siding can be used at an installed cost which is competitive with other sidings of similar quality and character.
Alternatives Within Invention
Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. For example, the siding pieces 40 and 54 may be made without top extensions 46 and bottom recesses 48 without departing from the teachings of my invention. Another example is use of the siding and corner pieces on gables and dormers, where the end pieces intersect with a sloping roof. Although I have described in detail the method of installing the siding from the bottom up, the teachings of my invention are equally applicable to top down construction. And although I have depicted four alternate embodiments of the top and bottom surfaces of the corner pieces 100, others within the teachings of my invention will be apparent to persons skilled in the art. Numerous characteristics and advantages of the invention covered by this document have been set forth in the foregoing description. It will be understood that other forms of the full corner log siding are contemplated by the present invention and that numerous modifications may be made by those with skill in the art without departing from the spirit and scope of the invention defined by the appended claims.
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Log siding for an existing structure to give the appearance of traditional full log construction. The corner pieces are preformed in two cooperating shapes to fit snugly together at the corners of the structure. One type of corner piece has three perpendicular planes at its inner end, to abut against the corner of the structure. The second corner piece has concave arcs at its inner end, to fit snugly against the rounded surfaces of the first corner pieces. The siding pieces are square cut at one end of each wall to fit against the end of the first type of corner piece and are cut in concave arcs at the opposite end of each wall to fit snugly against the rounded shapes of the logs at the corner. The siding can be speedily erected at the site with a minimum of field cutting.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is a continuation-in-part of copending U.S. patent application Ser. No. 14/122,675 filed as international application No. PCT/JP2012/071913 on Aug. 29, 2012,
TECHNICAL FIELD
[0002] The present invention relates to a review text output system, and a review text output method, and more particularly, to outputting review texts about commercial transaction objects such as merchandise, services, and information.
BACKGROUND ART
[0003] In the field of electronic commercial transaction, some Web pages for selling merchandise bear review texts about the article of merchandise, or include a link to a Web page that bears review texts about the article of merchandise. A review text is a piece of writing written as feedback or an evaluation on an article of merchandise, and is created by a user (reviewer) of an electronic commercial transaction system to be posted to the system. In JP2011-154527A, a similar system is disclosed. A user who reads review texts can know what evaluations have been made on an article of merchandise by other users, and put the evaluations to use in selecting merchandise for himself/herself.
SUMMARY OF INVENTION
[0004] An object of the present invention is to provide a review text output system, and a review text output method, which can output a review text which is beneficial to a search user.
[0005] A review text output system according to an aspect of the present invention includes: at least one processor; and at least one memory storing a plurality of instructions that, when executed by the at least one processor, cause the at least one processor to perform operations including: obtaining a first condition, which is a search condition for searching one or more commercial transaction objects; obtaining a second condition, which is a search condition for searching one or more commercial transaction objects; identifying one or more first review texts about one or more commercial transaction objects that satisfy the first condition and one or more second review texts about one or more commercial transaction objects that satisfy the second condition, the first review texts and the second review texts being created by a common reviewer; and outputting the second review texts. The first condition indicates a commercial transaction object related to a search user review text which has already been created by a search user. The identification of the first review texts and the second review texts includes a calculation of a degree of similarity between the search user review text and the first review texts and an identification of the first review texts and the second review texts based on the degree of similarity.
[0006] A review text output method according to an aspect of the present invention, includes: a step of obtaining a first condition, which is a search condition for searching commercial transaction objects, using at least one processor; a step of obtaining a second condition, which is a search condition for searching commercial transaction objects, using the at least one processor; a step of identifying one or more first review texts about one or more commercial transaction objects that satisfy the first condition and one or more second review texts about one or more commercial transaction objects that satisfy the second condition using the at least one processor, the first review texts and the second review texts being created by a common reviewer; and a step of outputting the second review texts using a display. The first condition indicates a commercial transaction object related to a search user review text which has already been created by a search user. In the step of identifying, the first review texts and the second review texts are identified based on a degree of similarity between the search user review text and the first review texts.
BRIEF DESCRIPTION OF DRAWINGS
[0007] FIG. 1 An overall view of a computer network that includes an electronic commercial transaction server system according to an embodiment of the present invention.
[0008] FIG. 2 A diagram illustrating an example of a top page which is provided by the electronic commercial transaction server system.
[0009] FIG. 3 A diagram illustrating an example of a merchandise list page which is provided by the electronic commercial transaction server system.
[0010] FIG. 4 A diagram illustrating an example of an individual merchandise item review text page which is provided by the electronic commercial transaction server system.
[0011] FIG. 5 A diagram illustrating an example of an individual merchandise item page which is provided by the electronic commercial transaction server system.
[0012] FIG. 6 A diagram illustrating an example of a review text search condition entry page which is provided by the electronic commercial transaction server system.
[0013] FIG. 7 A diagram illustrating an example of a review text search result page which is provided by the electronic commercial transaction server system.
[0014] FIG. 8 A diagram illustrating an example of an extended review text search condition entry page which is provided by the electronic commercial transaction server system.
[0015] FIG. 9 A diagram illustrating an example of an extended review text search result page which is provided by the electronic commercial transaction server system.
[0016] FIG. 10 A diagram illustrating an appendix to the extended review text search result page which is provided by the electronic commercial transaction server system.
[0017] FIG. 11 A diagram illustrating the configuration of a merchandise database.
[0018] FIG. 12 A diagram illustrating the configuration of a review text database.
[0019] FIG. 13 A diagram illustrating the configuration of a merchandise item-based review text list.
[0020] FIG. 14 A flow chart illustrating processing of generating data for the extended review text search result page.
[0021] FIG. 15 A diagram illustrating a modification example of the processing of generating the data for the extended review text search result page.
[0022] FIG. 16 A diagram illustrating a modification example of the extended review text search condition entry page.
[0023] FIG. 17 A diagram illustrating a modification example of the extended review text search result page.
[0024] FIG. 18 A diagram illustrating the configuration of a merchandise database according to a modification example.
[0025] FIG. 19 A diagram illustrating a modification example of a review comparison field.
[0026] FIG. 20 A flow chart illustrating processing of generating data for the review comparison field according to the modification example.
[0027] FIG. 21 A flow chart illustrating processing of generating data for the review text search result page according to another embodiment of the present invention.
[0028] FIG. 22 A flow chart illustrating processing of narrowing down the review text search.
DESCRIPTION OF EMBODIMENTS
[0029] An embodiment of the present invention is described below in detail with reference to the drawings.
[0030] FIG. 1 is an overall view of a computer network 10 which includes an electronic commercial transaction server system 12 according to the embodiment of the present invention. As illustrated in FIG. 1 , the computer network 10 includes the electronic commercial transaction server system 12 , a plurality of user computers 14 , and a plurality of store computers 16 . The electronic commercial transaction server system 12 is made up of a single computer (server) or a plurality of computers (servers), and is connected to a wide area network 18 , which is the Internet or the like. The electronic commercial transaction server system 12 provides a virtual shopping mall service for users of the user computers 14 and the store computers 16 to buy and sell merchandise. The electronic commercial transaction server system 12 has a function of registering and outputting a review text about merchandise, and represents the review text output system according to a mode of the present invention.
[0031] Each of the user computers 14 is a computer used by a user who purchases merchandise, and is connected to the wide area network 18 by cable or wireless connection to hold data communication to/from the electronic commercial transaction server system 12 . The user computer 14 is, for example, a personal computer or a portable terminal such as a cellular phone or a smartphone, and includes input means such as a keyboard and/or a pointing device and display means such as an LDC. A Web browser is installed in the user computer 14 and enables the user computer 14 to access the electronic commercial transaction server system 12 via the wide area network 18 in order to transmit various types of data to the electronic commercial transaction server system 12 and display a Web page provided by the electronic commercial transaction server system 12 . The user computer 14 uses the Web browser to purchase desired merchandise, or to create data of a review text (writing that conveys an evaluation or feedback on a review subject) about purchased merchandise (a review subject) and register the created data in the electronic commercial transaction server system 12 . The Web browser can also be used to receive review text data created by other users from the electronic commercial transaction server system 12 and display the data.
[0032] Each of the store computers 16 is a computer used by a user who sells merchandise, and is connected to the wide area network 18 by cable or wireless connection to hold data communication to/from the electronic commercial transaction server system 12 . The store computer 16 is, for example, a personal computer, and includes input means and display means. The store computer 16 , too, can be a portable terminal such as a cellular phone or a smartphone, of course. A Web browser is installed in the store computer 16 as well to enable the store computer 16 to access the electronic commercial transaction server system 12 via the wide area network 18 in order to register information of merchandise for sale.
[0033] FIG. 2 is a diagram illustrating a top page of the virtual shopping mall provided by the electronic commercial transaction server system 12 . The top page is in a Web page format, and is displayed based on data that is transmitted from the electronic commercial transaction server system 12 in response to a request from the user computer 14 . As illustrated in FIG. 2 , an entry form 20 , a search button 22 , a merchandise genre button group 24 , and a review search button 26 are displayed on the top page. The review search button 26 is a button for requesting a Web page on which a review text search condition is entered as described later. The entry form 20 is a field where the user enters a merchandise search condition via the input means. In this embodiment, the user enters a letter string that is included in a merchandise name in the entry form 20 .
[0034] The search button 22 is a button for transmitting a merchandise search request, which contains a letter string entered in the entry form 20 , from the user computer 14 to the electronic commercial transaction server system 12 , and is clicked with the pointing device. In response to the merchandise search request, the electronic commercial transaction server system 12 searches a merchandise database for merchandise whose merchandise name includes the letter string contained in the request, and transmits data (not shown) of a Web page that shows results of the search to the user computer 14 .
[0035] The merchandise genre button group 24 includes merchandise genre buttons corresponding respectively to a plurality of merchandise genres such as “foods”, “liquors”, “clothes”, and “books”. With a click of a merchandise genre button, the user computer 14 displays a Web page (not shown) that contains subordinate merchandise genre names belonging to a merchandise genre that corresponds to the clicked button. Subsequently clicking on the button of a merchandise genre at the bottom causes the user computer 14 to display a Web page that contains descriptions of articles of merchandise belonging to the merchandise genre.
[0036] FIG. 3 illustrates a merchandise list page that is displayed by the display means of the user computer 14 when the user selects a root merchandise genre “liquors”, an intermediate merchandise genre “wines”, and a sub-merchandise genre “French wines” in the order stated. The merchandise list page illustrated in FIG. 3 displays, for each article of merchandise belonging to the sub-merchandise genre “French wines”, an image of the merchandise, the merchandise name, the names of stores selling the merchandise, prices, and the count of registered review texts. The merchandise name is displayed by a merchandise button 28 . The review text count is displayed by a “display review texts” button 30 . By clicking on the “display review texts” button 30 , an individual merchandise item review text page illustrated in FIG. 4 is displayed on the user computer 14 . A click of the merchandise button 28 causes the user computer 14 to display an individual merchandise item page illustrated in FIG. 5 .
[0037] On the individual merchandise item review text page of FIG. 4 , a merchandise description field 32 for merchandise that is the subject of a review text (review subject) is placed at the top of the page, and many review fields 34 which display reviews created and registered by users (reviewers) are placed below the merchandise description field 32 . The merchandise description field 32 displays the merchandise name, the name of a store selling the merchandise, and a price. The merchandise name is designed as a button, and the individual merchandise item page of FIG. 5 is displayed on the user computer 14 also by clicking on the button. Each of the review fields 34 displays the name (nickname) of a user who is the reviewer, an image that indicates an evaluation value given by the reviewer on the review subject, and a review text. However, the electronic commercial transaction server system 12 is configured so that a reviewer can specify whether or not to disclose the name (nickname) of the reviewer when registering a review text in the electronic commercial transaction server system 12 , and the name of a reviewer who has specified not to disclose the name is not displayed in the review field 34 . In this case, a special name determined in advance such as “purchaser” in FIG. 4 may be displayed instead. If inclined to purchase the merchandise displayed in the merchandise description field 32 as a result of reading the review fields 34 , the user can view the individual merchandise item page immediately by clicking on the merchandise name button that is included in the merchandise description field 32 .
[0038] The individual merchandise item page of FIG. 5 displays an image of the merchandise, the merchandise name, the name of a store selling the merchandise, a price, and a description of the merchandise. The page also displays a pull-down menu 36 for entering the order quantity, a “shopping cart” button 38 , and a button 40 for displaying the individual merchandise item review text page of FIG. 4 . When deciding to purchase based on the merchandise description and other types of information, the user sets the order quantity with the use of the pull-down menu 36 and then clicks on the “shopping cart” button 38 . In response, the electronic commercial transaction server system 12 stores the order quantity and the merchandise ID of the ordered merchandise in association with the communication session, and returns a Web page (not shown) for establishing the order to the user computer 14 . On the Web page for establishing the order, the user enters a user ID, a password, and other types of necessary information such as the shipping address and a settlement method, and then presses an “OK” button. Consequently, the entered information is transmitted to the electronic commercial transaction server system 12 , and the order related to the order quantity and the merchandise ID that have already been stored in association with the communication session is established.
[0039] When the review search button 26 is clicked on the top page of FIG. 2 , a review text search condition entry page illustrated in FIG. 6 is displayed on the user computer 14 . The Web page of FIG. 6 displays an entry form 42 , an “add” button 44 , and a “search” button 46 . The entry form 42 is a field where the user enters a search condition for searching for merchandise that is the review subject of a review text. In this embodiment, the user enters a letter string that is included in a merchandise name in the entry form 42 . When the user enter an arbitrary letter string in the entry form 42 and clicks on the “search” button 46 , the electronic commercial transaction server system 12 searches the merchandise database for merchandise whose merchandise name includes the letter string. The electronic commercial transaction server system 12 returns review texts that have the found articles of merchandise as the review subject to the user computer 14 in a Web page format. FIG. 7 illustrates a review text search result page displayed at this point on the user computer 14 . As illustrated in FIG. 7 , one or more review fields 48 which respectively display review texts found as a result of the search are arranged on this page. Each of the review fields 48 displays, in addition to a review text found as a result of the search, an image that indicates an evaluation value given by the reviewer on the review subject, and the name of a user who is the reviewer, the merchandise name of the merchandise that is the review subject of the review text in question, the name of a store selling the merchandise, and a price. One review field 48 is provided for each article of merchandise whose merchandise name includes a letter string entered in the entry form 42 ( FIG. 6 ), and each review field 46 displays, as a representative, one of review texts that have the merchandise in question as the review subject. Which review text is to be displayed in the review field 48 may be selected in accordance with various standards, for example, the created date, the letter count, or the degree of similarity between the reviewer and the user, or may be selected at random. The review field 48 also displays a button 50 which, when clicked by the user, causes the user computer 14 to display other review texts about the same merchandise.
[0040] When the “add” button 44 is clicked on the review text search condition entry page of FIG. 6 , an extended review text search condition entry page illustrated in FIG. 8 is displayed. This Web page is one of features of this embodiment, and displays two entry forms 52 and 54 and one “search” button 56 . The extended review text search condition entry page also displays an “add” button 55 , which is clicked in order to further increase entry forms in number. The entry forms 52 and 54 are fields where the user enters Condition 1 and Condition 2, respectively, which are each a search condition for merchandise that is a review subject. In this embodiment, the user enters letter strings included in merchandise names in the entry forms 52 and 54 . When the user enters letter strings in the two entry forms 52 and 54 and then clicks on the “search” button 56 , the electronic commercial transaction server system 12 receives and thus obtains Conditions 1 and 2 described above, generates data for an extended review text search result page illustrated in FIG. 9 , and returns the data to the user computer 14 .
[0041] The extended review text search result page of FIG. 9 displays a review comparison field 58 for each reviewer. Displayed at the head of each review comparison field 58 is the name of a user who is the reviewer. Two review fields are displayed in association with each other below the name of the user. Specifically, two review fields are arranged side by side.
[0042] Each review field displays the merchandise name of merchandise that is the review subject, the name of a store selling the merchandise, and a price in the upper half, and displays a review text in the lower half. The review field placed on the left-hand side of FIG. 9 is about merchandise whose merchandise name includes a letter string entered in the entry form 52 ( FIG. 8 ) (Condition 1). The review field placed on the right-hand side of FIG. 9 is about merchandise whose merchandise name includes a letter string entered in the entry form 54 ( FIG. 8 ) (Condition 2). Review texts written in the left and right review fields discuss different review subjects but are created and registered by the same reviewer. In order to illustrate that the left-hand side review field corresponds to Condition 1 whereas the right-hand side review field corresponds to Condition 2, a letter string “Wine A” of Condition 1 and a letter string “Wine B” of Condition 2 are displayed side by side at the top of the extended review text search result page.
[0043] In short, entering an arbitrary letter string as Condition 1 in the entry form 52 on the Web page of FIG. 8 causes the extended review text search result page of FIG. 9 to display a review text that has, as the review subject, merchandise whose merchandise name includes the entered letter string in the review field that is placed on the left-hand side of each review comparison field 58 . Entering an arbitrary letter string as Condition 2 in the entry form 54 on the Web page of FIG. 8 causes the Web page of FIG. 9 to display a review text that has, as the review subject, merchandise whose merchandise name includes the entered letter string in the review field that is placed on the right-hand side of each review comparison field 58 . The review fields which are horizontally adjacent to each other display review texts created and registered by the same reviewer. According to this embodiment, the user can easily read and compare review texts created and registered by the same reviewer out of review texts about merchandise whose merchandise name includes a letter string set as Condition 1 and review texts about merchandise whose merchandise name includes a letter string set as Condition 2. The user can thus easily know what evaluation or feedback has been given on two articles of merchandise that the user is interested in by one reviewer, and put the evaluation or feedback to use in selecting merchandise.
[0044] The display format of the review comparison field 58 is not limited to the one illustrated in FIG. 9 . It is sufficient if review texts by the same reviewer which correspond to different conditions are output in association with each other. For instance, the review texts may be arranged on top of each other. Alternatively, a link button may be displayed in the periphery of one of the review texts so that the other review text is displayed by clicking on the link button. Frame lines illustrated in FIG. 9 are not indispensable. In the case where one or both of conditions have a plurality of review texts that correspond to the condition, only some (for example, one) of the plurality of review texts may be displayed on the extended review text search result page, or all of the plurality of review texts may be displayed on the extended review text search result page. In the case of displaying a plurality of review texts that correspond to one search condition in a review field, the merchandise names, the names of stores selling the merchandise, prices, and review texts are arranged next to one another in the vertical direction or the horizontal direction (see FIG. 17 ).
[0045] Specifically, a plurality of review texts created by “Ken” may be found as a result of a search that uses a letter string “Wine A” as Condition 1. For instance, one reviewer may create review texts a plurality of times about “Wine A” sold at one store, or may create a review text about “Wine A” for each of different stores that sell “Wine A”. In the case where the same reviewer has created a plurality of review texts about merchandise that meets a condition as this, all of the review texts can be displayed in association with one another by, for example, aligning the review texts in a single line. Alternatively, only some of the review texts (e.g., the one created last) may be displayed on the extended review text search result page. In this case, a button bearing a letter string “view more” or the like is provided so that the rest of the review texts are displayed by clicking on the button.
[0046] Review texts that have, as the review subject, merchandise that satisfies Condition 1 may include one whose reviewer has not created or registered a review text about merchandise that satisfies Condition 2. There is also the reverse case where review texts that have, as the review subject, merchandise that satisfies Condition 2 include one whose reviewer has not created or registered a review text about merchandise that satisfies Condition 1. Therefore, as illustrated in FIG. 10 , review fields displaying review texts that fit into the former case may be arranged on top of one another on one of the left-hand side and the right-hand side (the left-hand side in FIG. 10 ), while review fields displaying review texts that fit into the latter case are arranged on top of one another on the other side (the right-hand side in FIG. 10 ) at the same time. The Web page of FIG. 10 may be a part (e.g., the bottom) of the extended review text search result page of FIG. 9 , or may be a separate Web page linked to the page of FIG. 9 .
[0047] A detailed description is given below on information processing executed in the electronic commercial transaction server system 12 , in particular, information processing for generating data of the extended review text search result page and returning the data to the user computer 14 . The configuration and information processing of the electronic commercial transaction server system 12 described herein are implemented by a program that is run on the electronic commercial transaction server system 12 . This program may be downloaded from another computer via the wide area network 18 , or may be read out of a computer-readable information storage medium such as a DVD-ROM or a CD-ROM.
[0048] A plurality of types of databases stored in a large-scale storage device that is included in the electronic commercial transaction server system 12 are described first. The large-scale storage device may be built inside or separate from a computer that is the center of the electronic commercial transaction server system 12 .
[0049] FIG. 11 is a diagram schematically illustrating a merchandise database which is included in the electronic commercial transaction server system 12 . As illustrated in FIG. 11 , the merchandise database stores, for each article of merchandise, a merchandise ID, Genre 1, Genre 2, Genre 3, a merchandise name, a price, the name of a store selling the merchandise, and a merchandise description in association with one another. The merchandise ID is information for uniquely identifying an article of merchandise that is traded in the electronic commercial transaction server system 12 . Genre 1 is information for identifying a root merchandise genre such as “liquors” to which merchandise belongs. Genre 2 is information for identifying an intermediate merchandise genre such as “wines” to which merchandise belongs. Genre 3 is information for identifying a sub-merchandise genre such as “French wines” to which merchandise belongs. The merchandise description is information such as the size, weight, and other specifications of the merchandise, a recommendation message from the store selling the merchandise, and an image of the merchandise. A worker of a store who is planning to put new merchandise on sale enters genres as Genre 1, Genre 2, and Genre 3, the merchandise name, a price, and a merchandise description on the store computer 16 , following the guidance of a merchandise information entry page (not shown) which is received from the electronic commercial transaction server system 12 , and transmits these pieces of information to the electronic commercial transaction server system 12 along with store identification information. The electronic commercial transaction server system 12 newly issues a merchandise ID, and stores the various types of information received from the store computer 16 together with the issued merchandise ID. In this embodiment where a plurality of stores use the electronic commercial transaction server system 12 , the same merchandise may be registered by a plurality of stores.
[0050] FIG. 12 is a diagram schematically illustrating a review text database which is included in the electronic commercial transaction server system 12 . As illustrated in FIG. 12 , the review text database stores, for each review text, a review text ID, the user ID of the reviewer, the name of a user who is the reviewer, the merchandise ID of merchandise that is the review subject, a review text, a disclosure flag, and a purchaser flag in association with one another. The review text database may additionally store the date of creation of the review text. The review text ID is information for identifying a review text uniquely throughout the electronic commercial transaction server system 12 . The disclosure flag is information indicating whether or not a user who is the reviewer wishes to disclose his/her name as described above, and has a value “1” which indicates that the user wishes to disclose or a value “0” which indicates that the user does not wish to disclose. The review text, which is writing conveying an evaluation or feedback on a review subject as described above, includes here an evaluation value (rank) given by the reviewer on the review subject. The review text may further include a period over which the reviewer has purchased the merchandise, how many times the reviewer has purchased the merchandise, and the total count of pieces of the merchandise that the reviewer has purchased. The purchaser flag indicates whether or not the reviewer has actually purchased the review subject. In the case of displaying a review text that is created by a user who is not a purchaser, a message to that effect is desirably displayed along with the review text based on the purchaser flag.
[0051] To create and register a review text, the user computer 14 transmits information for identifying merchandise and an instruction to create a review to the electronic commercial transaction server system 12 . The electronic commercial transaction server system 12 transmits to the user computer 14 a review text entry page (not shown) for creating and registering a review text that has the merchandise identified by the merchandise ID in question as the review subject. The user computer 14 enters text information of the review text and a disclosure flag value, following the guidance of the review text entry page, and transmits these pieces of information to the electronic commercial transaction server system 12 along with a user ID and the merchandise ID of the review subject. The electronic commercial transaction server system 12 newly issues a review text ID, and stores the various types of information received from the user computer 14 in the review text database together with the issued review text ID. A user name that is associated with the user ID in this case is obtained from a user database (not shown). FIG. 13 is a diagram schematically illustrating a merchandise item-based review text list which is stored in the large-scale storage device included in the electronic commercial transaction server system 12 . The list records, for each merchandise ID, the review text ID of every review text that has merchandise identified by the merchandise ID as the review subject, along with the count of the review text IDs. The list of FIG. 13 is information derived from the review text database of FIG. 12 , and is automatically updated by the electronic commercial transaction server system 12 each time the review text database is updated.
[0052] The electronic commercial transaction server system 12 refers to the merchandise database, the review text database, and the merchandise item-based review text list to generate data of a Web page to be displayed on the user computer 14 . To generate data for the merchandise list page of FIG. 3 , for example, the electronic commercial transaction server system 12 extracts from the merchandise database a record in which a sub-merchandise genre specified by the user is recorded as “Genre 3”, and obtains an image of the merchandise, the merchandise name, the name of a store selling the merchandise, and a price from the record. The electronic commercial transaction server system 12 also obtains the count of review texts about this merchandise from the merchandise item-based review text list, with a merchandise ID included in the extracted record as a key. Based on the obtained information, the electronic commercial transaction server system 12 composites data for the merchandise list page of FIG. 3 .
[0053] To generate data for the individual merchandise item review text page of FIG. 4 , the electronic commercial transaction server system 12 extracts a record that is stored in the merchandise database in association with the merchandise ID of merchandise specified by the user, and obtains an image of the merchandise, the merchandise name, the name of a store selling the merchandise, and a price from the record. The electronic commercial transaction server system 12 also obtains a review text ID group from the merchandise item-based review text list, with the merchandise ID included in the extracted record as a key. For each obtained review text ID, the electronic commercial transaction server system 12 refers to the review text data base to obtain the user ID of a reviewer, a user name, and a review text that are associated with the review text ID. Based on the thus obtained information, the electronic commercial transaction server system 12 composites data for the individual merchandise item review text page of FIG. 4 .
[0054] To generate data for the individual merchandise item page of FIG. 5 , the electronic commercial transaction server system 12 extracts a record that is stored in the merchandise database in association with the merchandise ID of merchandise specified by the user, and obtains an image of the merchandise, the merchandise name, the name of a store selling the merchandise, a price, and a merchandise description from the record. Based on the thus obtained information, the electronic commercial transaction server system 12 composites data for the individual merchandise item page of FIG. 5 .
[0055] To generate data for the review text search result page of FIG. 7 , the electronic commercial transaction server system 12 extracts from the merchandise database a record in which the merchandise name includes a letter string transmitted from the user computer 14 . With a merchandise ID that is included in the extracted record as a key, a review text ID group is obtained from the merchandise item-based document list. The electronic commercial transaction server system 12 refers to the review text database to obtain the user ID of a reviewer, a user name, and a review text that are associated with one of review text IDs in the obtained review text ID group. The selected one of the review text IDs may be a randomly selected ID or may be the ID of a review text that has the latest date of creation. Based on the thus obtained information, the electronic commercial transaction server system 12 composites data for the review text search result page of FIG. 7 .
[0056] To create data for the review text search result page of FIG. 9 , processing illustrated in FIG. 14 is executed. This processing is executed by obtaining in the electronic commercial transaction server system 12 a letter string relevant to Condition 1 and a letter string relevant to Condition 2 which are transmitted from the user computer 14 . In this processing, the electronic commercial transaction server system 12 first obtains review text IDs that are related to a letter string entered as Condition 1 on the review text search condition entry page of FIG. 8 , and the user IDs of the reviewers (S 101 ). Specifically, the electronic commercial transaction server system 12 first obtains from the merchandise database the merchandise ID of merchandise whose merchandise name includes a letter string entered as Condition 1. The electronic commercial transaction server system 12 next obtains from the review text database a review text ID group that is associated with the obtained merchandise ID. The electronic commercial transaction server system 12 further obtains, from the review text database, for each obtained review text ID, a user ID that is associated with the review text ID and that is included in a record where the flag indicates that the option to “disclose” has been chosen. The user ID that is included in a record where the flag indicates that the option to “disclose” has been chosen is obtained because the review text search result page of FIG. 9 displays a review text along with the name of a user who is the reviewer. Next, the electronic commercial transaction server system 12 obtains review text IDs that are related to a letter string entered as Condition 2 on the review text search condition entry page of FIG. 8 , and the user IDs of the reviewers, in the same manner as in S 101 (S 102 ).
[0057] Thereafter, the electronic commercial transaction server system 12 selects one of the user IDs of the reviewers obtained in S 101 (S 103 ), and determines whether or not the selected user ID is included among the user IDs obtained in S 102 . In the case where the selected user ID is included, the electronic commercial transaction server system 12 obtains, from the review text IDs obtained in S 102 , the review text ID of a review text created by a reviewer who has the selected user ID (S 104 ). In the case where at least one review text ID to be obtained is found in S 104 (S 105 ), the electronic commercial transaction server system 12 generates data for the review comparison field 58 about the reviewer who is identified by the user ID selected in S 103 , and outputs the data to a file (S 106 ).
[0058] Specifically, the electronic commercial transaction server system 12 obtains from the user database (not shown) the name of a user who is identified by the user ID selected in S 103 , and outputs the user name to a file. The electronic commercial transaction server system 12 further obtains, from among the review text IDs obtained in S 101 , the review text ID of a review text created by a reviewer who has the output user ID, and obtains a review text and a merchandise ID that are associated with the obtained review text ID from the review text database. The electronic commercial transaction server system 12 also obtains a merchandise name, a store name, and a price that are associated with the obtained merchandise ID from the merchandise database. Thereafter, the electronic commercial transaction server system 12 generates data for a review field (for Condition 1) which displays the name of merchandise, the name of a store selling the merchandise, a price, and a review text based on the thus obtained information, and outputs the data to the file.
[0059] The electronic commercial transaction server system 12 next obtains from the review text database a review text and a merchandise ID that are associated with the review text ID obtained in S 104 . The electronic commercial transaction server system 12 also obtains from the merchandise database a merchandise name, a store name, and a price that are associated with the obtained merchandise ID. Thereafter, the electronic commercial transaction server system 12 generates data for a review field (for Condition 2) which displays the name of merchandise, the name of a store selling the merchandise, a price, and a review text based on the thus obtained information, and outputs the data to the file.
[0060] The electronic commercial transaction server system 12 then repeats S 103 through S 106 until every reviewer user ID obtained in S 101 is selected (S 107 ). After every reviewer user ID obtained in S 101 is selected, the electronic commercial transaction server system 12 completes data for the review text search result page of FIG. 9 based on the file generated in S 106 , and then returns the data to the user computer 14 (S 108 ). When completing the data, the electronic commercial transaction server system 12 arranges review fields that correspond to Condition 1 and review fields that correspond to Condition 2 next to each other, with the Condition 1 review fields on the left-hand side and the Condition 2 review fields on the right-hand side. In the case where the same reviewer has created a plurality of review texts about merchandise that meets Condition 1 as described above, all of the review texts may be displayed in the review fields that correspond to Condition 1 in association with one another by, for example, aligning the review tests in a single line. Alternatively, only some of the review texts (e.g., the one created last) may be displayed in the review fields that correspond to Condition 1.
[0061] In the processing of FIG. 14 , review texts about merchandise that satisfies a first condition are obtained as well as the user IDs of the reviewers of the review texts. Also obtained are review texts about merchandise that satisfies a second condition and the user IDs of the reviewers of the review texts. The user IDs relevant to the first condition and the user IDs relevant to the second condition are checked for a common user ID and, when there is a common user ID, review texts created and registered by a reviewer who is identified by the common user ID are displayed next to each other in the horizontal direction. Out of review texts about merchandise that satisfies the first condition and review texts about merchandise that satisfies the second condition, those created by a common reviewer can thus be identified and output in association with one another.
[0062] FIG. 15 is a modification example of the processing of FIG. 14 . In the processing of FIG. 15 , the electronic commercial transaction server system 12 first obtains review text IDs that are related to a letter string entered as Condition 1 on the review text search condition entry page of FIG. 8 , and the user IDs of the reviewers (S 201 ). Specifically, the electronic commercial transaction server system 12 first obtains from the merchandise database the merchandise ID of merchandise whose merchandise name includes a letter string entered as Condition 1. The electronic commercial transaction server system 12 next obtains from the review text database a review text ID group that is associated with the obtained merchandise ID. The electronic commercial transaction server system 12 further obtains, from the review text database, for each obtained review text ID, a user ID that is associated with the review text ID and that is included in a record where the flag indicates that the option to “disclose” has been chosen.
[0063] The electronic commercial transaction server system 12 next selects one of the user IDs of the reviewers obtained in S 201 (S 202 ), and obtains the review text ID of a review text that satisfies Condition 2 from among review texts the reviewer of which is a user identified by the selected user ID (S 203 ). Specifically, the electronic commercial transaction server system 12 searches the review text database for the merchandise ID of merchandise that is the review subject of a review text the reviewer of which is a user identified by the selected user ID, and obtains the found merchandise ID if the merchandise ID is included in a record where the flag indicates that the option to “disclose” has been chosen. The electronic commercial transaction server system 12 next determines whether or not a merchandise name that is associated with the obtained merchandise ID satisfies Condition 2. In the case where the merchandise name satisfies Condition 2, the electronic commercial transaction server system 12 obtains the review text ID of a review text the review subject of which is merchandise identified by the obtained merchandise ID and the reviewer of which is a user identified by the user ID selected in S 202 .
[0064] In the case where at least one review text ID to be obtained is found in S 203 (S 204 ), the electronic commercial transaction server system 12 generates data for the review comparison field 58 about a reviewer who is identified by the user ID selected in S 202 , and outputs the data to a file (S 205 ). Specifically, the electronic commercial transaction server system 12 obtains from the user database (not shown) the name of a user who is identified by the user ID selected in S 202 , and outputs the user name to a file. The electronic commercial transaction server system 12 further obtains the review text ID of a review text created by a reviewer who is identified by the selected user ID from among the review text IDs obtained in S 201 , and obtains a review text and a merchandise ID that are associated with the obtained review text ID from the review text database. The electronic commercial transaction server system 12 also obtains from the merchandise database a merchandise name, a store name, and a price that are associated with the obtained merchandise ID. Thereafter, the electronic commercial transaction server system 12 generates data for a review field (for Condition 1) which displays the name of merchandise, the name of a store selling the merchandise, a price, and a review text based on the thus obtained information, and outputs the data to the file.
[0065] The electronic commercial transaction server system 12 next obtains from the review text database a review text and a merchandise ID that are associated with the review text ID obtained in S 203 . Also obtained from the merchandise database are a merchandise name, a store name, and a price that are associated with the obtained merchandise ID. Thereafter, the electronic commercial transaction server system 12 generates data for a review field (for Condition 2) which displays the name of merchandise, the name of a store selling the merchandise, a price, and a review text based on the thus obtained information, and outputs the data to the file.
[0066] In the case where there is no review text ID to be obtained in S 203 , on the other hand, the electronic commercial transaction server system 12 skips S 205 . The electronic commercial transaction server system 12 then repeats S 202 though S 205 until every reviewer user ID obtained in S 201 is selected (S 206 ). After every reviewer user ID obtained in S 201 is selected, the electronic commercial transaction server system 12 completes data for the review text search result page of FIG. 9 based on the file generated in S 205 , and then returns the data to the user computer 14 (S 207 ).
[0067] In the modified processing of FIG. 15 , review text IDs related to merchandise that satisfies a first condition are obtained as well as the user IDs of reviewers who have created review texts identified by the review text IDs. Out of the obtained user IDs of the reviewers, the user ID of a reviewer who has created a review text about merchandise that satisfies a second condition is identified. The review text about the merchandise that satisfies the second condition which has been created by the reviewer having the identified user ID is then obtained. In this manner, too, review texts created by a common reviewer can be identified out of review texts about merchandise that satisfies the first condition and review texts about merchandise that satisfies the second condition, and can be output in association with one another.
[0068] In the description given above, the user enters two different letter strings included in a merchandise name as Condition 1 and Condition 2 respectively on his/her own on the review text search condition entry page of FIG. 8 . However, the present invention is not limited to this mode. For instance, instead of selecting merchandise based on whether or not a merchandise name includes an entered letter string, the electronic commercial transaction server system 12 may allow the user to enter a merchandise ID to select merchandise that is identified by the entered merchandise ID. In this case, a merchandise ID that is the first condition may be entered by the user with a keyboard, or a merchandise ID associated with information about a specific article of merchandise, such as the name of the merchandise, may be obtained as the first condition when the information is clicked. For instance, a mode may be employed in which, with a click of the button 40 on the individual merchandise item page of FIG. 5 , the merchandise ID of merchandise displayed on the page is transmitted from the user computer 14 to the electronic commercial transaction server system 12 . The electronic commercial transaction server system 12 sets the transmitted merchandise ID as Condition 1. In this case, the electronic commercial transaction server system 12 is allowed to automatically set a merchandise ID that is Condition 2. For example, if the merchandise IDs of articles of merchandise that are related to each other are stored in the electronic commercial transaction server system 12 in advance, once a merchandise ID that is Condition 1 is obtained, the merchandise IDs of one or more related articles of merchandise that has been stored in association with the obtained merchandise ID can be read and set as the second condition. This way, a review text about merchandise introduced on the Web page of FIG. 5 and a review text about related merchandise that has been created by the same reviewer can be displayed immediately with a click of the button 40 on the Web page.
[0069] Instead of specifying letter strings that are included in merchandise names, a root merchandise genre, an intermediate merchandise genre, or a sub-merchandise genre may be specified as the first condition and the second condition. Specifically, as illustrated in a Web page of FIG. 16 , pull-down menus 64 and 66 for further selecting merchandise genres may be displayed for the first condition and the second condition, respectively, in addition to entry forms 60 and 62 for entering letter strings that are included in merchandise names. The pull-down menus 64 and 66 are each designed so as to display all sub-merchandise genres in a list format and to enable the user to specify one of the displayed genres arbitrarily. The user enters a letter string in the entry form 60 , or selects one sub-merchandise genre from the pull-down menu 64 , as Condition 1. The user further enters a letter string in the entry form 62 , or selects one sub-merchandise genre from the pull-down menu 66 , as Condition 2, and then clicks on a “search” button 68 .
[0070] The electronic commercial transaction server system 12 receives Condition 1 and Condition 2, generates data for the Web page of FIG. 17 , and returns the data to the user computer 14 . Data for the Web page of FIG. 17 can be generated by processing similar to the one illustrated in the flow chart of FIG. 14 or FIG. 15 . Specifically, when searching for merchandise that satisfies Condition 1 or Condition 2 in S 101 or S 102 of FIG. 14 or in S 201 or S 203 of FIG. 15 , the electronic commercial transaction server system 12 searches for merchandise whose merchandise name includes a letter string received as Condition 1 or Condition 2 in the case where the received Condition 1 or Condition 2 is a letter string, and obtains the review text ID of a review text about the found merchandise and the user ID of the reviewer of the review text. In the case where the received condition is the specification of a sub-merchandise genre, the electronic commercial transaction server system 12 searches the merchandise database for merchandise for which the received merchandise genre is stored as “Genre 3”, and obtains the review text ID of a review text about the found merchandise and the user ID of the reviewer of the review text. The rest of the processing is the same as in FIG. 14 and FIG. 15 .
[0071] As illustrated in FIG. 17 , according to this modification example, a review comparison field 70 is provided for each reviewer. In the review comparison field 70 , a review field about merchandise whose merchandise name includes a specified letter string or merchandise that belongs to a specified sub-merchandise genre and a review field about merchandise whose merchandise name includes a separately specified letter string or merchandise that belongs to a separately specified sub-merchandise genre are arranged side by side, with the former placed on the left-hand side of the page and the latter placed on the right-hand side of the page. According to this modification example, by entering a letter string that is included in the name of merchandise in an entry form as Condition 1 and specifying as Condition 2 a sub-merchandise genre to which the merchandise belongs, the user can easily read and compare a review text about an article of merchandise with a review text about another article of merchandise that belongs to the same sub-merchandise genre and that has been created and registered by the same reviewer. Alternatively, specifying a sub-merchandise genre for Condition 1 and Condition 2 each allows the user to compare review texts about two sub-merchandise genres. For instance, the user can determine which of French wine and Italian wine to purchase by reading and comparing review texts about a sub-merchandise genre “French wines” and review texts about a sub-merchandise genre “Italian wines”. A letter string of Condition 1 and a letter string of Condition 2 are displayed side by side at the top of the extended review text search result page of FIG. 17 in order to illustrate that the left-hand side review field corresponds to Condition 1 whereas the right-hand side review field corresponds to Condition 2. A word “genre” is added to the displayed letter string in the case where a sub-merchandise genre is specified as Condition 1 or Condition 2.
[0072] As described above, when a merchandise ID is used as Condition 1, the electronic commercial transaction server system 12 is allowed to automatically determine and obtain a sub-merchandise genre that is Condition 2. For instance, when a merchandise ID is specified in the entry form on the review text search condition entry page of FIG. 6 and then the “search” button 46 is clicked, the electronic commercial transaction server system 12 obtains a sub-merchandise genre to which merchandise identified by the received merchandise ID belongs from Genre 3 of the merchandise database, and uses the obtained genre as Condition 2. The user thus only needs to specify one merchandise ID in order for the electronic commercial transaction server system 12 to output a Web page as the one illustrated in FIG. 17 . Needless to say, a review text search result page as the one illustrated in FIG. 17 may be output also by obtaining the merchandise ID of merchandise that is introduced on the individual merchandise item page of FIG. 5 and a sub-merchandise genre to which the merchandise belongs when the button 40 is clicked on the page, and setting the merchandise ID and the sub-merchandise genre as Condition 1 and Condition 2.
[0073] The review text search result page of FIG. 9 or FIG. 17 displays current review texts of the same reviewer about a plurality of articles of merchandise. Therefore, the premise of the page is that the same user purchases a plurality of articles of merchandise of the same type over a short period of time and creates and registers review texts about those articles of merchandise. However, it is very rare for some articles of merchandise that the same user purchases the same type a plurality of times. Wines, socks, detergents, and food, for example, are articles of merchandise that are expected to be replaced/replenished in a short period of time, whereas vacuum cleaners and refrigerators are articles of merchandise that are not expected to be replaced/replenished so often in a short period of time. The merchandise database therefore may store for each article of merchandise a flag that indicates whether or not the merchandise is expected to be replaced/replenished as illustrated in FIG. 17 . The electronic commercial transaction server system 12 in this case may process only records in which the flag indicates that replacement/replenishment is expected when generating the review text search result page of FIG. 9 or FIG. 17 . The processing time is thus cut short. This flag may be set manually by an administrator, or may be set automatically based on the actual purchase histories of many users. The flag may also be set for each merchandise genre (e.g., sub-merchandise genre), instead of flagging each article of merchandise.
[0074] Displaying the review comparison field in a mode that distinguishes a feature of each review text from the rest, such as highlighting, underlining, or framing the feature or using a different font or a different color for the feature, facilitates a comparison between review texts for the user. FIG. 19 illustrates a review comparison field in which features of review texts are framed. The features may be words of a specific part of speech such as adjectives, or may be fragments that match keywords stored in advance. The features may also be words of a specific part of speech or keywords that are not included in other review texts, and are displayed in a mode that distinguishes the features from the rest.
[0075] FIG. 20 is a flow chart for generating data for the review comparison field of FIG. 19 . Processing of FIG. 20 is executed when display data is generated for the respective review texts in S 108 of the flow chart of FIG. 14 and in S 207 of the flow chart of FIG. 15 . The electronic commercial transaction server system 12 first performs morphological analysis on each review text (S 301 ). A word of a specific part of speech, for example, an adjective word, is extracted from the review text that corresponds to the first condition (S 302 ). The electronic commercial transaction server system 12 determines whether or not the extracted word is included in the review text that corresponds to the second condition, determines the extracted word as a feature when the extracted word is not included, and performs display differentiation on the feature by highlighting or the like (S 303 ). Similarly, a word of a specific part of speech is extracted from the review text that corresponds to the second condition (S 304 ). The electronic commercial transaction server system 12 determines whether or not the extracted word is included in the review text that corresponds to the first condition, determines the extracted word as a feature when the extracted word is not included, and performs display differentiation on the feature by highlighting or the like (S 305 ).
[0076] According to the electronic commercial transaction server system 12 described above, review texts about an article or articles of merchandise that respectively satisfy a plurality of search conditions are displayed by the display means of the user computer 14 . In addition, review texts that have been created by a common reviewer and that respectively correspond to different search conditions are displayed in association with one another. The user can therefore easily know opinions of other users on an article or articles of merchandise that satisfy one search condition and an article or articles of merchandise that satisfy another search condition. The system according to this embodiment is particularly effective for cases where users often compare a plurality of articles of merchandise actually bought, or cases where one article of merchandise is replaced by another article of merchandise. In the case of merchandise that is a consumable article but is not inexpensive, in particular, users would want to avoid purchasing merchandise that is not to their tastes. This embodiment enables a user to easily know opinions of other users, and thus prevents such an event.
[0077] Next, still another embodiment of the present invention is described. In the processing according to this embodiment, on a review text search condition entry page illustrated in FIG. 6 , a search user (a user who obtains a search result) enters a search condition. As a result thereof, a review text search result page illustrated in FIG. 7 is displayed on the display of the user computer 14 . However, this embodiment is characteristic in that a review texts of other users whose sense of evaluation on a merchandise is similar to that of the search user, that is, a similar reviewer, is selectively included in the review text search result page.
[0078] In this embodiment, as a first search condition of a merchandise, a merchandise ID of a merchandise which is an evaluation subject of a search user review text that has already been created by a search user is used. Further, as a second search condition of a merchandise, a condition entered by the search user on the review text search condition entry page illustrated in FIG. 6 is used.
[0079] In this embodiment, the electronic commercial transaction server system 12 obtains a review text about a merchandise which satisfies a first search condition (a first review text) and a review text about a merchandise which satisfies a second search condition (a second review text). Here, the first review text and the second review text are created by the same reviewer. As this reviewer, a person whose sense of evaluation on a merchandise is similar to that of the search user, that is, a similar reviewer, is selected.
[0080] Therefore, the electronic commercial transaction server system 12 obtains a review text of another reviewer on a merchandise which has already been reviewed by the search user as the first review text. Then, the degree of similarity between the first review text and the review text which has already been created by the search user is calculated. In this case, a feature vector may be generated based on a keyword used in each review text. Alternatively, it may be configured that evaluation points as to a plurality of evaluation items such as “rich sourness,” “rich aroma,” “rich astringency,” “rich aroma of wooden barrel,” and “rich flavor of fruit” are included in each review text, and a vector having each evaluation point as a constituent is set as a feature vector of the review text. The electronic commercial transaction server system 12 may set a distance between feature vectors as the degree of similarity between the first review text and the review text which has been created by the search user.
[0081] The electronic commercial transaction server system 12 selects a similar reviewer from among reviewers who created a review text on both a merchandise which satisfies the first search condition and a merchandise which satisfies the second search condition based on the degree of similarity calculated this way. For example, one or more reviewers who created the first review text having the largest one of the above degree of similarity may be selected, and one or more reviewers who created the first review text having the above degree of similarity equal to or more than a predetermined threshold value may be selected.
[0082] The electronic commercial transaction server system 12 generates data for displaying the second review text created by the similar reviewer selected this way in the form of the review text search result page illustrated in FIG. 7 , and returns it to the user computer 14 .
[0083] Thus, according to this embodiment, the second review text by the similar reviewer is selectively included in the review text search result page. As a result thereof, the second review text which is beneficial to the search user can be selectively displayed.
[0084] Note that the merchandise ID used as the first search condition may be an ID of a merchandise which has already been purchased by the search user. This way, a similar reviewer can be identified based on a review text on a merchandise which the search user actually purchased. Further, the merchandise ID used as the first search condition may be an ID of a merchandise which belongs to a genre same with that of a merchandise that satisfies the second search condition. This way, a second review text by a reviewer whose sense of evaluation on a merchandise which belongs to the genre same with that of the merchandise that satisfies the second search condition is similar to the search user can be displayed, which makes the review text search result page more beneficial.
[0085] Note that the review text search result page may contain the first review text of each of similar reviewers. In this case, as illustrated in FIG. 9 , it is desirable to arrange the first review text and the second review text side by side or on top of one another and associate them with one another for each similar reviewer. This way, the search user can see if the similar reviewer truly has a sense of evaluation similar to his by reading the first review text.
[0086] FIG. 21 is a flow chart illustrating processing of generating data for a review text search result page according to this embodiment. The processing illustrated in this figure is executed by the electronic commercial transaction server system 12 . In this processing, in the beginning, one pair of a review text which has already been created by a search user and an ID of a merchandise which is a subject of that review text is selected (S 401 ). Specifically, in the review text database illustrated in FIG. 12 , a record, a user ID of the search user is in the “user ID of reviewer” field of which, is extracted. Here, it may be configured that only records in which “1” meaning that a reviewer actually purchased the merchandise is set in “purchaser flag” are extracted. Further, it may be configured that only records including a merchandise ID of a merchandise whose genre is the same with that of a merchandise that satisfies a search condition entered in the review text search condition entry page illustrated in FIG. 6 are extracted. Then, one of the extracted records is selected, and a pair of the review text and the merchandise ID is obtained.
[0087] Next, the electronic commercial transaction server system 12 searches for review text IDs, review texts and user IDs of reviewers using the obtained merchandise ID as the search condition (S 402 ). Specifically, the electronic commercial transaction server system 12 extracts records which are associated with the merchandise ID obtained in S 401 and are associated with a flag of “disclosure”. Then, review text IDs, review texts and user IDs are obtained from the extracted records.
[0088] Next, the electronic commercial transaction server system 12 calculates the degree of similarity between the review text selected in S 401 (the selected user review text) and each review text obtained in S 402 (S 403 ). Then, some of sets of review text IDs, review texts and user IDs are identified based on the calculated degrees of similarity (S 404 ). In this case, sets of review texts having the degree of similarity equal to or more than a predetermined value, their review text IDs and user IDs are selected. Alternatively, a set of a review text having the largest degree of similarity, its review text ID and user ID is selected.
[0089] Next, the electronic commercial transaction server system 12 selects one of the user IDs of the reviewers identified in S 404 (S 405 ), and from among review texts a reviewer of which is a user of the selected user ID, the electronic commercial transaction server system 12 obtains review text IDs of those satisfying a search condition entered in the review text search condition entry page illustrated in FIG. 6 (S 406 ). Specifically, the electronic commercial transaction server system 12 obtains, from the review text database, merchandise IDs of merchandises which are review subjects of review texts whose reviewer is a user of the selected user ID and which are included in a record where the flag indicates that the option to “disclose” has been chosen. Next, the electronic commercial transaction server system 12 determines whether or not merchandise names that are associated with the obtained merchandise IDs satisfy the entered search condition. Then, if they satisfy the search condition, the electronic commercial transaction server system 12 obtains review text IDs of review texts whose review subjects are merchandises of those merchandise IDs and whose reviewer is a user of the user ID selected in S 405 .
[0090] If there is at least one review text ID obtained in S 406 (S 407 ), the electronic commercial transaction server system 12 outputs review texts of the reviewer having the user ID selected in S 405 to a file (S 408 ).
[0091] Meanwhile, in S 407 , if there is no review text ID obtained in S 406 , the electronic commercial transaction server system 12 skips the processing of S 408 . Thereafter, the electronic commercial transaction server system 12 repeats the processing of S 405 through S 408 until all of the user IDs of the reviewers obtained in S 402 are selected. Once all of the user IDs of the reviewers obtained in S 402 are selected, then it determines whether or not all of the review texts of the search user and their merchandise IDs have been selected in S 401 (S 410 ), and repeats the processing of S 401 through S 409 until all of them are selected. Thereafter, based on the file generated in S 408 , data of the review text search result page illustrated in FIG. 7 is generated, and it is returned to the user computer 14 (S 411 ).
[0092] According to the above embodiment, review texts of other users whose sense of evaluation on a merchandise is similar to that of the search user, that is, similar reviewers, can be selectively included in the review text search result page, which can make it a page beneficial to the search user.
[0093] FIG. 22 is a flow chart illustrating processing selectively added prior to S 411 of FIG. 21 , and illustrates processing of narrowing down review texts included in the review text search result. In the processing illustrated in this figure, a clustering of all the review texts output in S 408 of FIG. 21 is performed (S 501 ). For example, the feature vector described above is generated for each of the review texts, and the review texts are clustered using the feature vectors. Then, a number of review texts belonging to each cluster is counted (S 502 ), and one or more clusters are selected depending on the number (S 503 ). For example, a cluster having the largest number of review texts may be selected, and all the clusters to which a predetermined number or more of review texts belong may be selected. Thereafter, based on review texts which belong to the selected cluster, data of the review text search result page illustrated in FIG. 7 is generated. Data generated this way is returned to the user computer 14 .
[0094] According to the above processing, a review text is included in review text search result data only in the case where there are many similar review texts of it, and as a result thereof a review text having a highly reliable content is selectively presented to a search user.
[0095] Note that the present invention is not limited to the embodiments described above.
[0096] For instance, while the description given above deals with only manufactured articles of merchandise as commercial transaction objects, the present invention can similarly be applied to services such as providing a hotel, an inn, or other lodging facilities, or offering a chance to use a golf course, and the trading of information such as movies or other types of video data, or news or other types of text data.
[0097] In the description given above, a review text is output by transmitting and outputting data for a Web page that displays the review text to the user computer 14 , and displaying the data on the display means of the user computer 14 . However, the present invention can use any format for data transmitted from the electronic commercial transaction server system 12 to the user computer 14 , and can use any output format on the user computer 14 . For instance, the user computer may print a review text.
[0098] In the description given above, review texts respectively corresponding to two search conditions are output in association with each other. Instead, review texts respectively corresponding to three or more search conditions may be output in association with one another.
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For making it possible to output a review text beneficial to a search user, a review text output system includes: at least one processor; and at least one memory storing a plurality of instructions that, when executed by the at least one processor, cause the at least one processor to perform operations including: obtaining a first condition, which is a search condition for searching one or more commercial transaction objects; obtaining a second condition, which is a search condition for searching one or more commercial transaction objects; identifying one or more first review texts about one or more commercial transaction objects that satisfy the first condition and one or more second review texts about one or more commercial transaction objects that satisfy the second condition, the first review texts and the second review texts being created by a common reviewer; and outputting the second review texts. The first condition indicates a commercial transaction object related to a search user review text which has already been created by a search user. The identification of the first review texts and the second review texts includes a calculation of a degree of similarity between the search user review text and the first review texts and an identification of the first review texts and the second review texts based on the degree of similarity.
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RELATED APPLICATIONS
[0001] This application is related to and claims priority to a provisional application entitled “PROCESS FOR RECOVERING SCRAP FIBER” filed May 16, 2013, and assigned Ser. No. 61/824,059.
FIELD OF THE INVENTION
[0002] The present invention is directed to a process for recovering fiber from post-consumer or post-industrial textile scraps and is particularly directed to recovering denim fiber as an intermediate product for subsequent utilization in a variety of products.
BACKGROUND OF THE INVENTION
[0003] Post-consumer and post-industrial textile scraps frequently present a disposal problem to original manufacturers of textile products such as clothing and the like. Such scrap material is usually baled for disposal or sale to subsequent processors. The textile or fabric material may consist of a variety of textiles such as cotton, and may comprise a combination of textile material. Such bales normally range in size from 100 pounds to 1,200 pounds. Occasionally, such scrap material may be in loose form and simply collected in large plastic bags. The difficulty with reprocessing any such textile scrap materials is the fact that they are contaminated with a variety of metal items secured thereto such as buttons, zippers, and particularly in view of denim clothing, decorative designs implemented on the pockets and elsewhere on jeans and jackets. The metals utilized in such clothing applications may include stainless steel, brass, copper, aluminum, ferrous metals or other types of non-ferrous metals. Attempts to reclaim the fabric from such scrap material can be hazardous since attempts to recover the fabric from such scraps including metal creates excessive wear on processing equipment and includes the danger of fire resulting from sparks when such metal encounters the processing equipment during the attempt to recover the fabric material from the scraps.
SUMMARY OF THE INVENTION
[0004] The present invention is directed to a process for removing such metal objects from the scrap fabric material to permit the effective recovery of the fiber for subsequent utilization in other products. The scrap fabric material, such as baled scrap material from post-consumer or post-industrial textile manufacturing is fed from a robot feeder (if the scrap has been baled—otherwise a bulk feeder is utilized) and is provided to a chopper system. The chopper system cuts the material into strips through the utilization of a chopper or guillotine system. The strips are then supplied to a second chopper oriented 90° with respect to the first chopper to cut the strips essentially into squares. The size of the squares are chosen to be approximately 2″×2″ (5 cm×5 cm). The 2″ square scrap pieces may or may not include a metallic object such as a button.
[0005] The material, in the form of fabric squares that may or may not include a metal object is then fed by a discharge conveyor in a single layer spread over a high speed conveyor and is transported to a metal detection system for detecting the presence of scraps having metal attached thereto. The detector system provides an appropriate signal to actuate a pneumatic system including a plurality of air jets. As the scrap material containing the metal object reaches the end of the conveyor system, a jet of air is directed upon the scrap containing the metal object to eject it from the conveyor and propel it to a discard system; the scrap objects without metal attachments are supplied to another conveyor system for further processing.
[0006] The non-metal scraps are transported to a mixing or feeding unit for thorough mixings prior to being fed into a plurality of opening cylinders to produce reclaimable fiber material that is collected and sent to a baler or bagger for delivery to subsequent processing systems to thereby create products generated from the scrap fabric.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The present invention may more readily be described by reference to the accompanying drawings in which:
[0008] FIGS. 1A, 1B and 1C present a schematic representation of equipment useful for practicing the process of the present invention.
[0009] FIG. 2 is an enlarged schematic representation of a portion of the processing equipment of FIGS. 1A, 1B and 1C .
[0010] FIG. 3 is a schematic representation of a portion of the detection equipment incorporated in the process equipment of FIG. 1A .
[0011] FIG. 4 is a schematic representation useful for describing the separation and capture of fabric material for subsequent reprocessing and discard of material attached to metallic objects.
[0012] FIG. 5 is a schematic block diagram useful for describing a sorting/separating technique employed in the process of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0013] The process of the present invention may more readily be described by reference to suitable equipment for implementing the process.
[0014] Referring to the figures, the bulk post-consumer or post-industrial textile scraps may be supplied in baled form and supplied to a Robot unit 10 such as that manufactured by Pierret Inc. that automatically slices off material from the bales at a consistent rate and thus feeds the conveyor 12 to introduce the material into choppers 14 and 16 . It is important that the material to be processed in the remaining steps of the process be reduced in size to an appropriate dimension to permit the subsequent separation of those fabric pieces containing metallic objects from those that do not. In the process of the present invention two choppers are utilized, each chopper is a guillotine-type cutter such as that produced by Balkan Corporation and identified as DT62 Guillotine Cutter. A second cutter, identical to the first, is arranged to cut the materials at a 90° angle with respect to the first cutter, the end result of this orthogonal cutting are rectangular fabric pieces, essentially square, that may or may not contain a metallic object such as a button and the like. It has been found that the size of these fabric pieces preferably form a square of approximately 2″×2″ (5 cm×5 cm) or less. The choice of the smaller fabric pieces also increases the efficiency with which the process produces useable scrap fiber. The second cutter may be arranged to cut the material at an angle other than 90° that would result in a fabric piece having a parallelogram-shape. However, it is desirable to create smaller fabric pieces and the square configuration is the most desirable and efficient. Those fabric pieces having metallic objects, such as buttons, attached thereto will be discarded; the smaller pieces reduce the amount of fabric that will be discarded with the metallic objects thus recovering a greater percentage of the fabric being processed. The square samples of material are then supplied to a vibratory pan conveyor or chute feed 18 (such conveyor systems may be acquired from the Sicon Company). It is important to convey the scrap textile material so that it is evenly distributed on the conveyor belt; this leveling action by the conveyor allows the textile pieces having metal attached thereto to be separated from non-metal containing pieces of fiber.
[0015] The material is then deposited on a fast moving conveyor belt, typically referred to as an accelerator belt 20 . The faster the belt travels, the greater the fabric pieces will be dispersed on the belt to facilitate accurate detection and separation of those fabric pieces having metallic objects secured thereto. The width of the accelerator belt will depend on the volume of material that is being processed; the volume could typically be from 100 lbs. per hour to as much as 10,000 lbs. per hour of recycled textile material. All of the equipment in the system for practicing the process should be sized in relation to the amount of material that is being processed. The faster the accelerator belt travels, the greater the dispersion of the material on the belt; it has been found that the velocity of the accelerator belt can be up to 1,000 feet per minute although approximately 700 feet per minute is preferred.
[0016] The high speed or accelerator belt transports the fabric pieces through a detection system 25 that detects the existence of, and the position of, any metallic pieces attached to the fabric pieces. The metal detection and separation process may utilize different sorting techniques based upon induction, optical, or even X-ray technology. The latter technology, however, may present complications relating to shielding and work place safety issues. It has been found that inductive principles have best provided for the sorting of the fabric pieces. Referring to FIG. 2 , the induction technique employs a plurality of sensors 27 positioned beneath the accelerator belt 20 ; the sensors 27 transmit electromagnetic waves of a predetermined frequency. The conductivity of metal objects coming within the electromagnetic field inherently distort the field by absorbing electromagnetic energy as a result of the conductivity of the metal. The detectors or sensors 27 detect the variation of the electromagnetic field as a result of such inductive reactance. The detection of this event generates a signal that is provided to a pneumatic system to direct a short blast of compressed air through a selected nozzle 29 as the metallic object approaches or reaches the head pulley 30 to deflect the metal object, and attached fabric, to a destination for subsequent collection and possible further handling. A discard conveyor 35 is shown receiving the fabric pieces having metallic objects attached thereto. The fabric pieces that are metal-free exit the accelerator belt 20 at the head pulley 30 with a different trajectory and are collected on a conveyor 36 ( FIG. 1A ) for transport to the next step of the process. The different trajectories of the objects exiting the accelerator belt 20 at the head pulley 30 permits a divider 40 to separate the objects in the different trajectories.
[0017] Referring to FIG. 3 , a schematic representation of the detectors 27 positioned beneath the accelerator belt 20 is shown. In some instances, it may be necessary to incorporate a field generating antenna 28 above the belt whereby detectors may sense field distortions resulting from the passage of a metal object through the field on the conveyor. Some systems for detecting and sorting metal objects do not require this type of transmitting antenna and may instead simply detect distortions in the electric or electromagnetic field transmitted by the sensors caused by the presence of a metal object in the field.
[0018] Referring to FIG. 4 , is a schematic representation is shown of the separate trajectories of detected metallic objects and fabric pieces that are to be further processed. For simplicity, the schematic diagram of FIG. 4 shows the rejected metal items; however, it should be understood that the metal items will likely have attached pieces of fabric to which the metal is secured when the fabric material was originally formed into clothing.
[0019] Referring to FIGS. 1B and 1C , the recovered fabric (without metal) is delivered to a mixing box 50 for blending with previously sorted fabric pieces. The mixing box 50 may, for example, be a Feeding Unit manufactured by Balkan Corporation and designated as their DT-70-Feeding Unit.
[0020] The mixed fabric pieces are then conveyed to a plurality of opening cylinders 60 to “open” the fabric pieces and convert those pieces into original fiber form. The opening equipment may, for example, be obtained from Balkan Corporation and designated DT-30-Mege Pulling. These units incorporate rotating opening cylinders and convert the fabric to non-woven fibers. The number of opening devices or stages and the number of pins provided in the respective cylinders of the corresponding opening devices may be chosen depending on the fabric and the parameters of the desired end product and how the fabric it is to be fiberized.
[0021] Each of the opening cylinder units will contain its own air condenser and dust removal fan system 61 to deliver dust laden air to an appropriate collection system such as a dust sock or bag house. The embodiment shown in the drawings incorporates several opening cylinders, each having its own dust removal system; it is possible for the dust removal systems to be combined by a single system for the collection of dust laden air from all of the opening devices.
[0022] The opened fiber is pneumatically collected and provided to a baler 70 ; dust removal apparatus is included in this final step of the process where the opened fiber are baled. A suitable baling system may be obtained from Balkin Corporation and referred to as a Bale Press.
[0023] Referring to FIG. 5 , a schematic block diagram useful for describing a sorting/separating technique employed in the process of the present invention is shown. A plurality of sensors 80 are spaced across the width of the accelerator belt. The sensors continuously detect the presence of any electrically conductive objects being conveyed by the belt. The detection of a metallic object results in a signal from the individual sensor to a sensor controller 82 . The controller provides information corresponding to the detection of a metal object by one or more of the sensors and provides information concerning the detection, including which sensor (the location transversely of the belt) to a central processor 85 . A conveyor speed sensor 88 also provides conveyor belt speed information to the processor. Thus, having received a signal from the sensor controller that a sensor has detected a metal object and having received conveyor speed information, the processor can provide a triggering signal to a pneumatic valve driver 90 to open the corresponding valve 92 and admit pneumatic pressure from the pneumatic pressure source 93 to the appropriate air nozzle 94 . The opening of the corresponding valve causes the targeted blast of air to contact the fabric piece having a metal object connected thereto and cause the metal object, and attached fabric piece, to exit the belt at the head pulley in a trajectory to be deposited on a waste conveyor and subsequently transported for disposal or further handling. Fabric pieces not attached to metallic objects thus travel the accelerator belt without impingement by an air blast and are conveyed over the head pulley onto a conveyor system for transport to the mixing box and subsequent handling in the present process
[0024] The present invention has been described in terms of selected specific embodiments of the apparatus and method incorporating details to facilitate the understanding of the principles of construction and operation of the invention. Such reference herein to a specific embodiment and details thereof is not intended to limit the scope of the claims appended hereto. It will be apparent to those skilled in the art that modifications may be made in the embodiments chosen for illustration without departing from the spirit and scope of the invention.
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The process for removing metal objects such as buttons, zippers and the like from fabric material to permit recovery of the fabric. The fabric is cut or chopped into strips and subsequently cut again to provide smaller pieces of fabric that may or may not contain a metal object secured thereto. The pieces of fabric are applied to a conveyor and exposed to a metal detector that triggers a plurality of pneumatic nozzles to direct a stream of high pressured air to the fabric pieces having metal attached thereto and deject those pieces from the conveyer while the fabric pieces without metal exit the conveyor having a different trajectory than the metal pieces and attached fabric material.
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This invention was made with government support under Contract No. W7405-ENG-36 awarded by the U.S. Department of Energy to The Regents of The University of California. The government has certain rights in the invention.
FIELD OF THE INVENTION
The present invention relates generally to the preparation of actinide boride materials suitable for intermediate storage of actinide elements and, more particularly, to the use of low-temperature, solid-state metathesis reactions to prepare these materials.
BACKGROUND OF THE INVENTION
Department of Energy strategy for plutonium has shifted in focus within the past decade from production and recycling to stabilization and disposal. This change results from the reduction in the nuclear stockpile and the accompanying need for plutonium disposition. Today's strategy uses plutonium oxide as the optimum intermediate (i.e. ≦50-year) storage form, even though John M. Haschke et al. reported in “Reaction of Plutonium Dioxide with Water: Formation and Properties of PuO 2+X ”, Science 287, 285 (2000), that PuO 2 slowly reacts with moisture to form hydrogen, causing numerous safety and storage concerns.
The area of actinide borides is underdeveloped, in part due to the high temperatures required to produce these materials (See, e.g., H. A. Eick and R. N. R. Mulford, J. Inorg. Nucl. Chem. 31, 371 (1969). The list of known binary thorium- and uranium-boride phases includes only ThB 4 , ThB 6 , ThB 66 , UB 2 , UB 4 , UB 12 , with little information reported on their chemical properties (See, e.g., J. J. Katz et al. The Chemistry of Actinide Elements , Chapman and Hall; New York, N.Y. (1986), pages 56, 280 and 317 for Th, U and Pu, respectively). In contrast, plutonium borides have been synthesized at lower temperatures but require the use of molten plutonium (800° C.), which is extremely corrosive (See, e.g., H. A. Eick, Inorg. Chem. 4, 1237 (1965)), or the use of PuH 3 (900° C.) (See, e.g., R. E. Skavdahl et al., Trans. Am Nucl. Soc. 7, 403 (1964)). Plutonium borides are known to be refractory, but other properties such as chemical behavior and stability have not been evaluated. In contrast, many transition metal and lanthanide borides, such as ZrB 2 (See, e.g., K. Su and L. G. Sneddon, Chem. Mater. 5, 1659 (1993) and L. Rao et al., J. Mater. Res. 10, 353 (1995)), and LaB 6 (See, e.g., S. S. Kher and J. T. Spencer, J. Phys. Chem. Solids 59, 1343 (1998)), have been extensively studied and have been used as refractory materials and corrosion-resistant coatings. It is therefore expected that some actinide-boride phases will also be corrosion resistant.
During the past two decades significant advances have been made in the low-temperature synthesis of highly refractory materials (See, e.g., K. H. Wynne and R. W. Rice, Ann. Rev. Mater. Sci. 14, 297 (1984) and R. W. Rice, Am. Ceram. Soc. Bull. 62, 889 (1983)). New methods, such as molecular precursors, pre-ceramic polymers, chemical vapor deposition, sol-gel and hydrothermal syntheses, low-temperature molten salts, self-propagating high-temperature synthesis (SHS), and solid-state metathesis reactions (SSM), virtually eliminate the problems associated with slow solid-state diffusion by mixing the constituents of the ceramic at a molecular level. SHS and SSM methods have been used successfully to synthesize transition metal borides, nitrides, and oxides and actinide oxides and nitrides at low- to moderate-temperatures (See, e.g., E. G. Gillan and R. B. Kaner, Chem. Mater. 8, 333 (1996), I. P. Parkin and J. C. Fitzmaurice, J. Mat. Sci. Lett. 13, 1185 (1994), and I. P. Parkin and J. C. Fitzmaurice, New J. Chem. 18, 825 (1994)). The key to low-temperature synthesis is identification of suitable precursors that lead to ceramic materials having the desired physical characteristics described above. However, no mention is made of generating actinide borides using low-temperature SSM.
Accordingly, it is an object of the present invention to provide a low-temperature method for preparing stable actinide boride ceramic compositions from commonly available or readily prepared actinide compounds.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the Invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
SUMMARY OF THE INVENTION
To achieve the foregoing and other objects, and in accordance with the purposes of the present invention, as embodied and broadly described herein, the method for preparing an actinide boride of an actinide element hereof includes the step of heating a mixture of a halide of the actinide element with a chosen amount of magnesium diboride such that a metathesis reaction occurs.
In another aspect of the present invention, in accordance with its objects and purposes, the method for preparing an actinide boride of an actinide element hereof includes the step of heating a mixture of an oxide of the actinide element with a chosen amount of magnesium diboride such that a metathesis reaction occurs.
In still another aspect of the present invention, in accordance with its objects and purposes, the method for preparing an actinide boride of an actinide element hereof includes the step of heating a mixture of an oxyhalide of the actinide element with a chosen amount of magnesium diboride such that a metathesis reaction occurs.
Benefits and advantages of the present invention include the conversion of already existing or readily generated actinide compounds into less-reactive, safer storage forms utilizing metathesis reactions which take place at readily attainable temperatures.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and form a part of the specification, illustrate an embodiment of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:
FIG. 1 shows the powder X-ray diffraction pattern for the water-washed solid product from the reaction of UCl 4 +2 MgB 2 for 1 d at 850° C. (top), and a powder X-ray diffraction pattern of UB 4 calculated from single-crystal data (bottom).
FIG. 2 shows X-ray powder diffraction patterns of the crude products of the reaction of UCl 4 with: (a) 0.5 MgB 2 ; (b) 1 MgB 2 ; (c) 2 MgB 2 ; and (d) 2.5 MgB 2 , at 850° C. for 1 d. The powder patterns-are normalized to a constant MgCl 2 peak height. The x-axis corresponds to pattern (a), while patterns b-d are offset by +0.5 degrees in 2 Θfrom pattern (a) for clarity. All powder patterns were taken with the sample under a dry, inert atmosphere.
DETAILED DESCRIPTION
Briefly, the present invention includes a method for the preparation of actinide borides by low-temperature, solid-state metathesis reactions as an alternative intermediate storage form for actinide elements. These materials are highly-refractory boride phases of plutonium and other actinides that are stable to moisture, are highly compact, and have many of the desired nonproliferation physical characteristics such as chemical inertness and stability to radiolytic decay. The basic reaction involves a source of boron, such as magnesium diboride with a halide, oxide or oxyhalide of the actinide.
Chlorides, bromides and iodides are all suitable halides since the respective heats of reaction readily drive the reactions to completions. Actinide halides include trichlorides and tetrachlorides, oxides include dioxides and oxyhalides include oxychlorides. Although the method of the present invention has been demonstrated for chlorides of several actinide elements and oxides thereof, it is anticipated that the above-described metathesis reactions will proceed well with bromides and iodides and actinide oxyhalides having chlorine, bromine, and iodine; as examples, UOCl 2 and ThOCl 2 and PuOCl can be used.
For actinide halides and oxyhalides, a fluxing agent such as potassium chloride, lithium chloride or calcium chloride, or eutectic mixtures of these salts is optional and assists in the intimate mixing of the reacting species at low temperatures by dissolving the actinide compound without taking part in the reaction. This results in shorter reaction times. As an example, a eutectic mixture of potassium and lithium chlorides melts at 352° C., and allows the metathesis reactions to take place at this low temperature. Sodium and cesium chlorides could also be used; the choice of fluxing agent relates to its low melting point and lack of reactivity with the species of interest. As an example, since UCl 4 has a low melting temperature, a fluxing agent would not be required. For the actinide oxides, a fluxing agent is mandatory since these materials have high melting temperatures and slow reaction times. Upper limits for the reaction temperature are limited by materials compatibility, expense and convenience; 850° C. has been found to be a preferred upper temperature limit, although higher reaction temperatures can be utilized.
Quartz and titanium reaction vessels have been successfully used. It is anticipated that tungsten would also be suitable.
When mixtures of borides are formed in the metathesis reaction, as in the case when uranium and plutonium trichlorides are converted, the addition of elemental boron permits the reaction to proceed to essential completion with the generation of substantially only the actinide tetraboride.
In accordance with the teachings of the present invention, suitable actinides include plutonium, uranium, thorium, americium, and neptunium.
Having generally described the invention, the following EXAMPLES provide additional details.
EXAMPLE 1
Preparation of UB 4 from UCl 4 and MgB 2 :
Typically, 50-250 mg of UCl 4 and 2 equivalents of MgB 2 were reacted in a vacuum-sealed 1.5 mL quartz tube by heating the mixture to 850° C. for 1 d (Although depleted uranium ( 238 U) was used, care must be taken in the handling and disposal of the starting materials and products since they are alpha particle emitters.). Sealed ampoules were run in furnaces in a fume hood to prevent contamination in the case of a tube rupture:
UCl 4 +2MgB 2 →UB 4 +2MgCl 2 (ΔH rxn =−58 kcal/mole)
After the reaction, the tubes were opened and the contents washed with water to remove soluble salts. The sample was then rinsed with ethanol and dried. The bromide of uranium may also be employed in place of the chloride.
Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are shown in the accompanying drawings. Turning now to FIG. 1, a powder X-ray diffraction (pXRD) pattern of the washed product is compared with a UB 4 pattern calculated from single-crystal data. From the similarity of the experimental pattern and the calculated pattern it is clear that UB 4 is the only crystalline phase readily identified in the remaining solid.
The reaction of UCl 4 with substoichiometric amounts of MgB 2 produces a mixture of crystalline phases composed of UB 4 , UCl 3 , and MgCl 2 . X-ray powder diffraction patterns of the reactions of UCl 4 +xMgB 2 , where x=0.5, 1, 2, and 2.5 for reactions conducted at 850° C. for 1 d are shown in FIG. 2 hereof. As the amount of MgB 2 in the reaction is increased, the amount of UCl 3 remaining in the reaction decreases while the amount of UB 4 produced increases. The presence of UCl 3 in the reaction mixture was also confirmed by single-crystal X-ray diffraction. This evidence suggests that MgB 2 acts as a reducing agent as well as a source of boron:
UCl 4 +0.5 MgB 2 →UCl 3 +0.5 MgCl 2 +B.
To support this hypothetical reduction of UCl 4 to UCl 3 and in order to better understand the nature of the reaction products, two sets of samples were taken for ICP-AES analysis. First, the reaction products were washed with 40 mL of distilled water and the filtrate collected. Separately, the water-insoluble, solid products were dissolved in 20 mL of 3.2 M HNO 3 . Any unreacted UCl 4 , as well as UCl 3 and MgCl 2 produced, will dissolve in the water; unreacted MgB 2 and UB 4 produced are insoluble in water and will remain in the solid. The resulting samples were analyzed for uranium, magnesium and boron content and compared with the initial amounts present in the reaction. At 0.5 equivalents (eq) of MgB 2 , almost all of the uranium (96%) and magnesium (83%) are present in the filtrate, which is consistent with the production of soluble UCl 3 and MgCl 2 as proposed above. This is also consistent with the lack of UB 4 and MgB 2 in the pXRD pattern of this sample (See, FIG. 2 a ). The lack of significant amounts of magnesium (1%) in the x=0.5 solid is consistent with formation of elemental boron as the only boron-containing production in the reduction reaction proposed above (i.e., no MgB 2 remains and no UB 4 has yet been formed).
With increasing amounts of MgB 2 (i.e., x≧0.5), the amount of uranium in the filtrate is expected to decrease and the amount in the solid increase due to the conversion of soluble UCl 3 into insoluble UB 4 . At x=2.5, 90% of the uranium was found to be in the solid product. If all of the uranium in the solid samples is in the form of UB 4 , the elemental boron in x=0.5 must be converted to UB 4 as x approaches 2.5 (See FIG. 2 d ). For all values of x, less than 4% of the magnesium is in the solid product; thus, all of the magnesium is dissolved in the filtrate (presumably as MgCl 2 ). This is consistent with the observation that no magnesium uranium boride ternary phases are present in pXRD patterns.
Experiments were also conducted to determine the effect of time (1-5 d) and temperature (600-850° C.) on the reaction of UCl 4 with 2 eq of MgB 2 , UCl 3 , and MgCl 2 . The major difference in these reactions is the crystallinity of the UB 4 ; as might be expected, longer reaction times and higher temperatures yield a more crystalline product.
Thus UCl 4 has been demonstrated to be converted in high yield (90+% by ICP-AES based on total uranium) to the refractory boride UB 4 by solid-state metathesis methods. No other uranium boride compounds were observed in these studies. These methods allow for the formation of crystalline boride materials at low temperatures (i.e., between 600 and 850° C.) using quartz reaction vessels.
EXAMPLE 2
Preparation of ThB 4 from ThCl 4 :
To 0.200 g of ThCl 4 (0.535 mmol), 0.0123-0.1474 g of MgB 2 (0.268-3.210 mmol; 0.5-6 equivalents (eq)) were added, and the mixture placed In a tantalum reaction vessel that was sealed under 1 atm of He. The reaction was heated to 850° C. over and held at that temperature for 5 d. After cooling, the reaction tubes were opened in an inert-atmosphere, dry glovebox. Powder X-ray diffraction samples were prepared, and the samples analyzed. It was found that both ThB 4 and ThB 6 form in the reactions.
EXAMPLE 3
Preparation of UB 4 from UCl 3 :
0.200 g of UCl 3 (0.581 mmol) were combined with 0.040 g of MgB 2 (0.871 mmol; 1.5 eq) or with 0.040 g of MgB 2 (0.871 mmol; 1.5 eq) and 0.0753 g of B (6.969 mmol; 12 eq) in a tantalum reaction vessel that was sealed under 1 atm of He. The reaction was heated to 850° C. over and held at that temperature for between 1 h and 30 d. After cooling, the reaction tubes were opened in an inert-atmosphere, dry glovebox. Powder X-ray diffraction samples were prepared, and the samples analyzed. It was found that both a 50% mixture of UB 2 and UB 4 formed in the first case and only UB 4 when boron was added to the reactions. Thus, the addition of elemental boron permits the reaction to proceed to completion.
EXAMPLE 4
Preparation of UB 4 from UO 2 :
0.200 g of UO 2 (0.741 mmol), 0.0680 g of MgB 2 (1.481 mmol; 2 eq) and 0.55 g of KCl (0.74 mmol; 10 eq) as a flux material were placed into a tantalum reaction vessel that was sealed under 1 atm of He. The reaction was heated to 850° C. and held at that temperature for 5 d. After cooling, the reaction tube was opened in an inert-atmosphere, dry glovebox. A powder X-ray diffraction sample was prepared and the sample analyzed. It was found that UB 4 was the only uranium boride present in the reaction products. The use of LiCl and CaCl 2 , NaCl and CsCl, and eutectic mixtures thereof, as flux materials are expected to yield similar results. The use of low-melting fluxing agents should permit the metathesis reactions to occur at as low as about 350° C.; for example, a 44% eutectic mixture of LiCl in KCl melts at 352° C.
EXAMPLE 5
Preparation of PuB 4 from PuCl 3 :
5.0 g of PuCl 3 (14.5 mmol) are combined with up to 3.0 g of MgB 2 (65.2 mmol; 4.5 eq) in an open tantalum cylinder. The reaction was heated to 850° C. under a dry Ar atmosphere and held at that temperature for 1 d. After cooling, a powder X-ray diffraction sample was prepared and the sample analyzed. Powder X-ray diffraction revealed that PuB 2 and PuB 4 were present in the reaction products.
The foregoing description of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching.
The embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.
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The synthesis of actinide tetraborides including uranium tetraboride (UB 4 ), plutonium tetraboride (PuB 4 ) and thorium tetraboride (ThB 4 ) by a solid-state metathesis reaction are demonstrated. The present method significantly lowers the temperature required to ≦850° C. As an example, when UCl 4 is reacted with an excess of MgB 2 , at 850° C., crystalline UB 4 is formed. Powder X-ray diffraction and ICP-AES data support the reduction of UCl 3 as the initial step in the reaction. The UB 4 product is purified by washing water and drying.
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CROSS REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application No. 60/870,847 filed Dec. 20, 2006, hereby incorporated by reference herein in its entirety.
BACKGROUND
[0002] 1. Field
[0003] The invention relates to wired communication systems and specifically to controlling the impedance of an electrical signal interface of a network.
[0004] 2. Background
[0005] Consider several communication nodes that are part of the same coaxial cable network or other wired network. Each node connecting to the network presents an impedance at the point of connection. Mismatches between the impedance of the node and the impedance looking into the network cause reflections. Such reflections cause a multipath signal environment that impairs passage of the signal over the medium. The input and output of the nodes include active circuitry that changes its impedance when power is applied and removed. The impedance can also change when other events occur. For example, a reset of a node can temporarily deactivate circuitry. If the nature of the reflections is known, compensation can be provided. However, as the reflections change, the compensation must change also. Adaptation to such changes takes time to complete. Sub-optimal compensation of the changed environment can cause degradation in the performance of the network, including a reduction in link margins and an increase in the data error rate.
[0006] Accordingly, it is desirable to ensure that the communication channel and other operational nodes of the network are not disturbed when power is applied to, or removed from one or more nodes or when another event changes the impedance that the node presents to the network.
SUMMARY OF THE INVENTION
[0007] The presently disclosed method and apparatus controls the impedance that a node presents to a network to minimize or avoid disruptions to signals communicated over the network. More specifically, the presently disclosed method and apparatus controls the impedance presented to a network by a node when power is applied to, or removed from the node or when the node experiences a reset or other event that changes the impedance.
[0008] In one embodiment, an Impedance Control Device is used in conjunction with a “Transitioning Node”. A Transitioning Node is any node on the network for which the impedance that the node presents to the network is changing. The Impedance Control Device will typically be placed between the Transitioning Node and the network to alter the impedance presented by the Transitioning Node to the network. Changes to the impedance of the Transitioning Node may be due to power being applied, removed or due to any other condition that will change the impedance presented to the network, such as a reset.
[0009] The impedance of the Impedance Control Device causes the impedance presented to the network to slowly transition so the other nodes in the network (some of which may also be transitioning) will have time to adjust to the effect that the change in the impedance of the Transitioning Node has on the network. The other nodes in the network can adapt their modulation type, signal equalization, bit loading, or they can use any other compensation mechanism used to compensate for reflections caused by mismatched impedances in the network. Examples of such compensation include using various well-known techniques suitable for the modulation type used. The rate of the slow transition is dependent on the rate of adaptation. In another embodiment, the impedance presented to the network is held constant or nearly constant during an event by switching an interface between the Transitioning Nodc and the network away from the Transitioning Node and to a circuit within the Impedance Control Device which has a similar impedance which is held stable.
Power Transition Impedance Control
[0010] For a power down transition 1) the Impedance Control Device detects that the main power source has been removed. 2) The Impedance Control Device immediately switches to cause a circuit having a variable impedance to be presented to the network. The initial state of the variable impedance device is an impedance that is matched to the impedance presented by the Transitioning Node when the Transitioning Node has had power applied for a long enough time for its impedance to be stable. 3) Using some energy that was stored when the device was last powered on, slowly increase the impedance of the variable impedance circuit until the stored energy is depleted and the variable impedance circuit is at maximum impedance.
[0011] For a power up transition 1) a variable impedance device within the Impedance Control Device is placed in series with the Transitioning Node. 2) When the Impedance Control Device detects that the main power source has been applied, the Impedance Control Device sets the variable impedance device to the maximum impedance. Preferably, the Transitioning Node has been powered off long enough to cause its impedance to be very high. However, if the device is powered on or off before a given transition is fully complete, the new transition direction can increase (or decrease) the impedance from the intermediate impedance the Impedance Control Device last had. 4) Based on a timing circuit within the Impedance Control Device, the variable impedance circuit changes to a minimum impedance allowing time for the Transitioning Node in series with the variable impedance circuit to reach its operating impedance
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 shows a block diagram of an Impedance Control Device.
[0013] FIG. 2 shows an embodiment with a matching impedance connected during power off.
[0014] FIG. 3 shows a block diagram of a circuit to control the switches connected in series with circuit elements used to achieve impedance control at the node interface.
[0015] FIG. 4 illustrates another embodiment of an impedance control system.
[0016] FIG. 5 shows a power up/power down (PU/PD) control circuit.
[0017] FIG. 6 shows a transmit/receive (T/R) switch.
DETAILED DESCRIPTION
[0018] FIG. 1 shows a block diagram of an Impedance Control Device 100 having a switch 120 , a impedance matching circuit 150 and a controller 160 . Also shown is a node 115 which includes a transmitter 130 , a receiver 140 and a voltage reference 155 . A network is connected through a signal interface 110 and the switch 120 to a node 115 . With the switch 120 set to connect the transmitter 130 to the signal interface 110 (the switch 120 in the position shown in FIG. 1 ), the impedance at the signal interface 110 looking back into the switch 120 is preferably matched to the impedance looking in the opposite direction (i.e., away from the switch 120 and into the network). This impedance can be 50 Ohms, 75 Ohms, or any other impedance value, typically depending upon the impedance of the cable or wire connected to the network. The position of the switch 120 is selected by a controller 160 . The controller 160 determines whether the node 115 is in transmit and receive mode and selects the position of the switch 120 accordingly. The controller 160 also detects changes in the power applied to the node 115 or detects other events that may cause the transmitter or receiver circuits to deactivate, such as a node reset event. When an event is detected, the controller 160 selects the position of the switch 120 corresponding to a matching circuit 150 appropriate to the detected event.
[0019] FIG. 2 shows an Impedance Control Device 400 coupled to a device interface 410 , such as a connector. The Impedance Control Device 400 includes the multi-position switch 120 , controller 160 , and matching circuit 150 of FIG. 1 . The Impedance Control Device 400 is coupled to the transmitter 130 and the receiver 140 . The device 400 provides a predictable impedance to a node (not shown) coupled to the device interface 410 during power off. When a loss of power is detected, a switch 430 within the switch 120 connects an impedance 420 to the device interface 410 to provide a predictable impedance as the power is removed from the transmitter 130 and/or receiver 140 . The impedance 420 may be implemented as either a resistance or a complex impedance. The switch 430 maintains a connection to the impedance 420 as long as the power remains off.
[0020] A transmitter amplifier 450 having a predetermined output impedance, for example, 75 Ohms in the case of a coaxial cable channel, is connected to the device interface 410 by a switch 435 within the switch 120 when the node is transmitting. A receiver amplifier 440 having a predetermined input impedance, also 75 Ohms, is connected to the device interface 410 by a switch 445 when the device is receiving. The impedance presented during transmission and reception is a combination of the intrinsic impedance of the amplifiers 440 , 450 and a series resistance 460 or a shunt resistance 470 to produce the desired total impedance. The impedance during transmission and reception takes into account the non-zero resistance of the switches 435 , 445 . Thus, in general, the active circuit impedance will be less than the desired 75 Ohms by an amount equal to the resistance of one of the switches 435 , 445 . The switches 435 , 445 preferably have equal resistance. Generally, the receiver amplifier 450 is connected to the device interface 410 except when the node connected to the device interface 410 is transmitting. When power is removed from the node, the switch 430 makes a connection to an matching impedance 420 , also 75 Ohms.
[0021] The switches 430 , 435 , 445 can be constructed using transistors. For example, the switch 435 can be a field effect transistor (FET) connected with a first lead 490 connected to a common terminal 480 , a second lead 492 connected to the series resistance 460 . The gate 494 on the FET is used to turn the transistor on (i.e., reduce the resistance between the first lead 490 and the second lead 492 ). In one embodiment, the transmitter amplifier 450 and receiver amplifier 440 are connected through transistors 435 , 445 that require positive bias on the gate to turn on the transistor 435 , 445 . The matching impedance 420 connects through a transistor 430 that uses a negative bias to turn off the transistor 430 . When power is removed, the negative bias is not generated and the gate voltage returns to zero volts and the transistor 430 conducts, thereby connecting the matching impedance 420 . In one embodiment, this transistor 430 can be implemented with a depletion mode MOSFET or other semiconductor device that conducts when no gate bias is present.
[0022] In another embodiment, when the controller 160 detects an event during which power remains, but the active circuitry is deactivated, such as during a reset event, the switch 120 selects the matched impedance 150 for the duration of the event. At the end of the event, the switch 120 returns to the state in which either the receiver 140 or transmitter 150 is selected, as appropriate.
[0023] In yet another embodiment, when an event is detected, the switch 120 selects the matching circuit 150 . In this embodiment, the matching circuit 150 has an impedance that is variable starting from an impedance that is equal to or similar to the impedance of the node when it is “on” and slowly changing to an impedance that is equal to or similar to the impedance of the node when it is “off”, or changing from “off” to “on”.
[0024] The rate of the slowly varying signals is dependent on the speed of adaptation of the network. The total transition time for changing the impedance can range from microseconds to minutes. The transition time can be different for the power up, power down, and event conditions. For example, the power down transition can take many seconds, while the power up transition can take microseconds.
[0025] As noted with regard to FIG. 2 , the switch 120 can be implemented with field effect transistors (FETs) where one terminal of each FET is connected to a common point and the other terminal is connected in series with each of the devices and the FETs are controlled to enable one FET at a time.
[0026] FIG. 3 shows a block diagram of a circuit to control the switches connected in series with circuit elements used to achieve impedance control at a node interface. Power on/off detection and signal control 260 detect the application or removal of power to the node by monitoring, for example, the 3.3-volt power supply of the node. When power is applied, signal control 260 asserts the power up signal. When power is removed, signal control 260 asserts the power down signal. Additionally, the signal control 260 is responsive to an event signal, such as device reset, and can initiate the power up or power down signals in response.
[0027] The power up signal passes through delay 270 to control RX_MUX, the signal used to select the receiver switch driving signal. The delay interval defines the period of time that RX_MUX selects the RXU_Cntl signal (varying voltage) to drive the switch. After the delay interval expires, RX_MUX selects the RX_Cntl (digital level) signal to drive the switch in the normal transmit/receive mode.
[0028] Signal transition control 280 creates a slow varying signal in response to the power up signal to produce RXU_Cntl, which drives the receiver switch to slowly turn on the switch and vary the resistance in series with the receiver circuit.
[0029] Signal transition control 280 can be an R-C network that creates an exponential voltage on a capacitor. Alternatively, signal transition control can be a constant current source that produces a substantially linear voltage across a capacitor. Signal transition control can be designed to discharge the capacitor quickly, and immediately change the output voltage level, when the input signal is deactivated, or to provide a slow transition in both directions of input signal transition.
[0030] Signal transition control 290 creates a slow varying signal in response to the power down signal to produce POR_Cntl*, which drives the matched impedance switch to slowly turn on the switch and vary the resistance in series. The power down signal can be an active low signal so that the inactive state maintains a voltage on a capacitor, thus storing energy. When the active-low power down signal is asserted, POR_Cntl* can be asserted to immediately turn on the matched impedance switch, then slowly drop the signal voltage to turn off the switch and increase the effective impedance at the node interface.
[0031] In one embodiment, the matched impedance is switched to the node interface upon power removal, then after transitioning to a high impedance and the other network nodes adapt to the new multipath environment, the un-powered node can be removed without a disruption in the multipath environment of the network. How the RX_MUX, RXU_MUX, and POR_Cntl* signals are used is discussed in further detail below with regard to FIG. 6 .
[0032] FIG. 4 illustrates another embodiment of an impedance control system having a power supply 180 , a voltage divider 190 , a power up/power down (PU/PD) control circuit 200 , a controller 165 , a transmit/receive (T/R) switch 310 , a transmit power amplifier (TX PA), a receive low noise amplifier (RX LNA) and a matching network 350 . In accordance with the embodiment shown in FIG. 4 , when power is applied, a first voltage of 3.3 volts and a second voltage of 2.5 volts are presented to the PU/PD control circuit 200 . The 2.5 volt power source is the voltage divider 190 . The PU/PD control circuit 200 outputs three signals, RXU_Cntl, POR_Cntl, and RX_MUX to the T/R switch 310 . These signals provide control to the switch as will be explained in greater detail below. The matching circuit 350 is placed in series between the network and the T/R switch 350 . A second RF path 195 from the network is provided directly to the T/R switch 310 . The second RF path 195 is connected through the T/R switch 310 to either the TX PA 330 or the RX LNA 340 , as will be explained in greater detail below. The determination as to whether the network is connected to the TX PA 330 , the RX LNA 340 or through the matching network 350 is controlled by the controller 165 .
[0033] Referring now to FIG. 5 , an example of the details of the PU/PD control circuit 200 is shown. FIG. 6 illustrates the details of one embodiment of the T/R switch 310 that is controlled by the PU/PD control circuit 200 of FIG. 5 . A Power On Reset Block 210 (POR) shown in FIG. 5 detects the transient of the power supply coming up from 0 to full operating power (vdd) or down from vdd to 0. Alternatively, the POR 210 can detect a transient on the power supply that is indicative of a power transition.
[0034] The POR 210 generates a signal entitled “POR_Cntl”. The POR_Cntl signal is initially in the logical “0” state (inactive) during a power up transition (i.e., when power is initially applied). The POR_Cntl signal is coupled to the input of an inverter 235 to create a signal entitled “POR_Cntl*”. POR_Cntl* is the logical inverse of POR_Cntl, however, when power is first applied, the inverter 235 does not have power and the output of the inverter 235 will remain low for some period of time. Power is supplied to the inverter 235 by the signal RXU_Cntl. As will be seen further below, the RXU_Cntl is connected indirectly to the 3.3 volt power supply line provided by the power supply 180 and rises more slowly then the 3.3 volt line directly from the power supply 180 .
[0035] POR_Cntl* is coupled to a switch 355 shown in FIG. 6 . When the voltage of POR_Cntl* is low, the switch 355 will be in a high impedance state (the switch is turned off). Thus, the matching network 350 shown in FIGS. 3 and 1B is not connected to the network. As shown in FIG. 5 , the power supply 180 provides 3.3 volts to the circuit 200 , but it will be understood by those skilled in the art that other voltages would also be appropriate. As noted above, RXU_Cntl is coupled to the 3.3 volt power supply line as well, but not directly. Rather, RXU_Cntl is coupled to the 3.3V power supply line through either an FET 220 or an FET 230 . In addition, a capacitor 250 is provided on the RXU_Cntl line. The capacitor 250 will cause the voltage on RXU_Cntl to rise relatively slowly compared to the voltage on the 3.3 volt power supply line. The signal RXU_Cntl is also coupled to the positive input to a comparator 240 . Power to the comparator 240 is applied directly from the 3.3 volt power supply 180 . The negative input to the comparator 240 is coupled to the 2.5 volt output of the voltage divider 190 . Once RXU_Cntl charges up to a level that is greater than the 2.5 volt line provided to the PU/PD control circuit 200 by the voltage divider 190 , the output RX_MUX transitions from a logical “0” level to a logical “1”.
[0036] The output RX_MUX of the comparator 240 is coupled from the comparator 240 shown in FIG. 5 to the “select” input of a multiplexer 347 shown in FIG. 6 . The RXU_Cntl signal is coupled from the PU/PD control circuit 200 of FIG. 5 to the “0” input of the multiplexer 347 shown in FIG. 6 . RXU_Cntl is increasing gradually from 0 volts to a full vdd level depending on the C_PD value and leakage current at this point. Up until that point, RX_MUX is at a logical zero. RX_MUX being at a logical “0” will cause the “0” input to be coupled to the gate of the FET 345 and a logical “1” will cause the multiplexer 347 to couple the signal coupled to the “1” input to the gate of the FET 345 . Accordingly, RXU_Cntl, which is provided from the controller 165 (shown in FIG. 4 ) and coupled to the “0” input of the comparator 240 , is passed through to the gate of the FET 345 . The signal applied to the gate of the FET 345 will keep the FET 345 initially at a high impedance and will slowly turn the FET 345 on as RXU_Cntl rises. When RXU_Cntl gets above the 2.5 volt reference voltage the FET 345 will be fully on. In addition, as RXU_Cntl rises above the 2.5 volt level, the comparator 240 will switch and RX_MUX will rise causing the multiplexer 347 to couple RX_Cntl to the gate of the FET 345 .
[0037] The signal POR_Cntl which is generated by the POR circuit 210 shown in FIG. 5 is at a high voltage (3.3 volts in the present embodiment) when the POR circuit 210 detects power. Resistor R_PU 212 and C_PU 214 create a slow changing voltage at node POR_PU at the gate of the FET 220 shown in FIG. 5 , which controls the N device 220 . When vdd rises from 0 to 3.3 volts, POR_Cntl is driven high and the N device 220 turns on. POR_Cntl* (the logical complement of POR_Cntl) is initially at low voltage level, since power is applied to the inverter 235 by RXU_Cntl. POR_Cntl* is coupled to the P device 230 which turns on and starts charging the capacitor C_PD 250 . By doing this, the signal RXU_Cntl is now at high level, ‘1’, that is, full vdd level, which can be 5V, 3.3V, 1.8V, 1.2V, or 1V or other voltage.
[0038] When power is removed, the POR circuit 210 drives its output, POR_Cntl, to a low voltage level. This causes the N device to turn off. POR_Cntl* is then driven to a high voltage by the inverter 235 . POR_Cntl* turns off the P device 230 , isolating the already charged tank capacitor C_PD 250 . By doing this, the signal RXU_Cntl remains at a high voltage level (full vdd level) and decreases gradually depending on the value of the capacitor C_PD 250 and the leakage current at this circuit node. RX_MUX drifts to a low voltage level no matter what is the state of RXU_Cntl is because the comparator 240 generating the RX_MUX is powered by the 3.3 volt power supply which has been powered down. The impedance of the RX LNA 340 is now high because the power to the RX LNA 340 is off. Furthermore, because POR_Cntl* is held at a high voltage, the FET 355 is held on and so the matching network 350 is coupled through the FET 355 to the network. As the voltage of POR_Cntl drops, the impedance through the FET 355 will start to increase and will change gradually from low impedance to high impedance.
[0039] It should be noted that the switch 310 can be implemented with individual switches in series with each of the switched components, each switch with a separate control signal. Any of the components can be connected to the common switch node using the corresponding control signal.
[0040] TX power amplifier 330 is connected to the network through the switch through FET 335 when the TX_Cntl signal is at a high voltage. TX_Cntl is generated by the controller 165 shown in FIG. 4 . It should be noted that any other switching device responsive to the control signal TX_Cntl may be used rather than the FET 335 shown in FIG. 6 .
[0041] During normal operation, RX_MUX will be high, and so the multiplexer 347 will couple RX_Cntl to the gate of the FET 345 . RX LNA 340 , or any other receiver component, is connected to the network through FET 345 . As noted above, FET 345 is controlled by either RX_Cntl (a digital signal) or RXU_Cntl (a varying level signal).
Power Shutdown Modes
[0042] These modes are designed for the case when the power supply is available, but it is desired to minimize device operating current.
[0043] Complete shutdown mode (C) is as complete a shutdown as possible while power is still being applied to the device. When shutdown mode C is enabled all active devices of the affected IC are disabled with the exception of the T/R switch, which is directed to connect the RF I/O port to the passive matching circuit. This mode is preferred for critical power conservation, such as battery backup operation for lifeline services.
[0044] Partial shutdown mode (P) is a partial shutdown mode. When shutdown mode P is enabled all transmit active devices are disabled. However, receive active devices remain enabled, and the T/R switch is directed to connect the RF I/O port to the receive path. This mode is recommended for all other power down requirements, such that power on and power off (sleep) states will have minimal impact to the system.
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The terminating impedance of a networked device in a wired communication channel is controlled to avoid an impedance discontinuity when power is applied and removed from the node or other event occurs that would change the impedance of the signal interface. When the node transmits or receives signals using the communication channel, the transmit or receive device presents a matched termination to the channel. When power is removed or the device is reset, the transmit and receive circuitry is not operational and the matched impedance is therefore maintained by a separate device. The impedance may be varied slowly from a match to a high impedance to allow other devices in the network to adapt to the change in multipath environment that results from the impedance change. Alternatively, the signal interface can be switched to a passive static impedance that is maintained while power is off or the disrupting event occurs.
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This application is a continuation-in-part of U.S. patent application Ser. No. 08/200,204, filed Jul. 23, 1994, now U.S. Pat. No. 5,481,819, which is a continuation-in-part of U.S. patent application Ser. No. 08/089,889, filed Jul. 12, 1993, now U.S. Pat. No. 5,425,299, which is a continuation-in-part of U.S. patent application Ser. No. 08/073,766, filed Jun. 8, 1993, now U.S. Pat. No. 5,355,608.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to laser sights for use on small firearms, particularly semiautomatic handguns and rifles.
2. Description of the Related Art
It is well known that even skilled marksman with a handgun have been unable to hit a target as close as 7 meters when attempting to draw the weapon and fire at speed. In target shooting, the shooter must obtaining the proper stance by carefully positioning the feet and the "free" hand to find the most stable condition, producing no muscular strain that will adversely effect the accuracy of the shot. Most importantly, the shooter must be able to obtain an identical position each time the weapon is fired to achieve the greatest accuracy. As the whole upper torso moves during each breath, breath control plays a vital role in the process. Since there can be no body movement at the time the trigger is fired, obviously the act of breathing must be stopped during the time the weapon is aimed and fired.
Sight picture and aim are critical if the shooter is to fire the most accurate shot or series of shots. When a mechanical pistol sight is properly aligned, the top of the front sight should be level with the top of the rear sight, with an equal amount of light on either side of the front sight. Using this sight picture requires that the shooter focus his shooting eye-so that the sights are in focus and the target is out of focus. Added to the difficulty, the trigger, all of the above must be maintained while the trigger is released using direct, even pressure to keep the barrel of the gun pointing at the target. These skills require tremendous practice, with each shot fired needing the utmost concentration if the shooter is to obtain maximum accuracy.
It is clear that the recommended methods of achieving maximum shooting accuracy useful for target shooting, must be severely modified when a handgun is used in a law enforcement situation. While the degree of accuracy necessary for target shooting and the distances and substantial lower, accuracy is still vital. Law enforcement official are instructed to fire only as a last resort, cognizant of the fact that their intended target will mostly be killed. Shooting to wound occurs only in the movies. Law enforcement officers typically use higher caliber handguns, mostly 9 mm, which are designed to immobilize with a single shot if that shot strikes a vital area. Given the inherent inaccuracies in the shooting process itself, exacerbated by the stress and fear of the police officer in what may be a life threatening situation for him/her, the exact location of the bullet where millimeters can mean the difference between death and survival cannot be known a priori by the even the most skilled marksman.
Mechanical sights have limited value in many situation where an officer must quickly draw his gun, perhaps while moving, and fire at a close target without sufficient time to properly obtain a sight picture. Under these circumstances, instinctive aiming, that is, not using the sights but rather "feeling where the gun barrel is pointing using the positioning of the hand holding the gun, is the preferred method. While this method, akin to the typical television cowboy shootouts, can be reasonably effective at short distances, obviously large errors in aiming are easily introduced, especially when the officer must frequently fire his/her weapon from a different hand position that has been used for practice. For example, bullet proof shields are used to protect the officer from being fired upon such as in a riot situation. In those circumstance, the officer must reach around his/her shield or other barricade and instinctively aim and fire his/her gun with the handgun in a very different orientation that would be experience if fired from a standing, drawn from a holster position. Small changes in barrel orientation due to the sight radius of the typical law enforcement handgun can produce substantial errors relative to the target. Accurate instinctive shooting is not considered practical beyond 20 feet for the average shooter.
The same problems face a soldier in a combat situation. While a rifle is inherently more accurate that a handgun, the stress of combat, the need to fire rapidly but accurately in order to survive is sufficient to introduce substantial errors into the sighting process. These problems are further exacerbated by the fact that most military personnel do not have sufficient practice time with their weapon to develop a high proficiency, particular in combat simulated situations.
An additional problem encountered in the military situation is the need for a sighting system that can be easily moved from one weapon to another. As warfare increases in sophistication, the need for more versatile armament increases correspondingly. Ideally, an operator should be able to quickly and confidently move the sighting system from one weapon to another without needing any field adjustments.
A solution to this problem for handguns has been the introduction of laser sights. The typical laser sight is mounted on the top on the handgun or on the bottom. The laser sight when properly aligned, places a red light dot on the target where the bullet will strike if the gun is fired. Using this type of sight, enables the law officer to rapidly instinctively properly position the weapon and be certain of his/her intended target. Using a laser sight enables accurate shots to be fired at distances of more than 50 feet, sufficient for most combat law enforcement situations requiring the use of handguns.
U.S. Pat. No. 4,934,086, issued to Houde-Walter on Jun. 19, 1990, discloses installing the laser sight within the recoil spring guide. The use of the recoil spring guide to house the laser sight components enables the firearm to be holstered in a normal manner. The use of the spring recoil guide presents alignment problems to ensure accuracy. In other words, the laser within the recoil guide is difficult to align with the barrel of the firearm. Therefore, misalignment of the sight resulting in poor accuracy is likely.
However, prior art laser devices have several disadvantages. As they are mounted either on the top or the bottom of the weapon, the balance of the gun is disturbed which makes it more difficult for the shooter to rapidly use his/her instinctive sighting technique to move gun into alignment for hitting the desired target. Also, since prior art laser sights are very bulky in comparison to traditional mechanical sights, the weapon cannot be used in a standard holster. Further, the laser sight is extremely vulnerable to being hit due to extending substantially beyond the normal profile of the weapon and thereby misalignment of the sight and defeating the advantages offered by the laser sight. A laser sight capable of being installed in a semi-automatic handgun, easily and accurately adjustable, is not disclosed in the prior art.
A laser sight for a standard military issue weapon such as the M-16 that can be attached to the weapon without requiring a major modification of the firearm is not available. Use of the type of laser sights discussed below for handguns will also exhibit the same type of problems relative to installation on an M-16.
Prior art laser devices have several disadvantages. As they are mounted either on the top or the bottom of the weapon, the balance of the gun is disturbed which makes it more difficult for the shooter to rapidly use his/her instinctive sighting technique to move gun into alignment for hitting the desired target. The particular design of the M-16, having a carrying handle on the top of the firearm, makes adding a prior art laser devices to this weapon impractical. Also, since prior art laser sights are very bulky in comparison to traditional mechanical sights, when used with a handgun, the weapon cannot be used in a standard holster. Further, the laser sight is extremely vulnerable to being hit due to extending substantially beyond the normal profile of the weapon and thereby misalignment of the sight and defeating the advantages offered by the laser sight. A laser sight capable of being installed in a semi-automatic handgun or on a military rifle such as an M-16, easily and accurately adjustable, and moveable from one weapon to another without the need for field adjustments is not disclosed in the prior art.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a laser module sight apparatus that can substantially fits within the profile of the weapon that the module is to be installed upon.
It is another object of the invention to provide a laser module sight apparatus that can be retro-fitted to standard semi-automatic handguns or to standard military rifles such as an M-16.
It is still another object of the invention to provide a laser module sight apparatus that can be easily moved from one weapon to another without the need for to align the laser located in the module.
It is still another object of the invention to provide a laser module sight apparatus that can be fitted to various semi-automatic handguns and military rifles requiring a minimum replacement of standard parts.
It is another object of the invention to provide a laser module sight apparatus that can easily adjusted by the user to permit accurately alignment of the laser sight with the barrel of the gun.
It is another object of the invention to provide a laser module sight apparatus that can be inexpensively produced using primarily commercially available parts.
It is another object of the invention to provide a laser module sight apparatus that can incorporate an infrared diode that makes the dot invisible to the naked eye, but clearly visible using standard night vision equipment.
It is still another object of the invention to provide a laser module sight that includes a removable flashlight module, incorporating both infrared and visible light.
It is another object of the invention to provide a laser module sight apparatus that is extremely light compared to existing lasers and their mounts.
It is still another object of the invention to provide a laser module sight apparatus that can be controlled using an easily operated keypad.
It is another object of the invention to provide a laser module sight apparatus that can be powered by commercially available batteries, providing at least several hours of service time before needing to be changed.
It is another object of the invention to provide a laser module sight apparatus that will incorporate a delay when the frame mounted switch is deactivated before the laser is turned off, thus permitting time for the user to activate the trigger switch without losing sight on the target.
It is another object of the invention to provide a laser module sight apparatus that will provide an adjustable pulse rate so that "friendly" laser beams can be distinguished from a laser beam from an enemy.
It is another object of the invention to provide a laser module sight apparatus that eliminates the need for a pressure pad on the grip handle which is awkward when holding the gun and requires adjustments to the shooter's grip to keep the laser off while maintaining stability.
The invention is a laser sight module for a firearm. A chassis mountable on said firearm is provided. A laser module, releasably attachable to said chassis, said laser module having a front face with at least one laser device housed within said chassis is provided. The light form said laser device exiting the front face of said chassis. A flashlight module, releasably attachable to said laser module, is provided. Said flashlight module has a front with at least one light source housed within said flashlight module. The light from said light source exits the front face of said flashlight module. Control means for controlling the operation of said laser module and said flashlight module is provided. Connection means for communication between said flashlight module and said laser module is provided such that a signal from an operator indicating said light source of said flashlight module is to be activated is communicated to said flashlight module from said laser module. Adjustment means connected between said chassis and said laser module is provided. Said adjustment means aligns said chassis with the barrel of said firearm, wherein said laser module can be easily moved to a different weapon so equipped without the need for additional adjustments to ensure that said laser module will accurately sight on a target.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of the modular laser apparatus mounted on a typical handgun.
FIG. 2 is a front view of the modular laser apparatus mounted on a typical handgun along section line AA of FIG. 1.
FIG. 3 is a partial exploded view along section line BB of FIG. 2.
FIGS. 3A-3C are more detailed views of parts of FIG.3.
FIG. 4 is a partial exploded view along section line BB of FIG. 2.
FIG. 5 is a partial cut-away bottom view of the battery compartment of the modular laser apparatus along section line CC of FIG. 1.
FIG. 6 is a side view of the modular laser apparatus mounted on a typical handgun.
FIG. 7 is a side view of the modular laser apparatus mounted on a typical rifle.
FIG. 8 is a front view of the modular laser apparatus along section line DD of FIG. 7.
FIG. 9 is a side view of the modular laser apparatus mounted on an SMAW-D.
DETAILED DESCRIPTION OF THE INVENTION
The invention is a modular laser sighting system adaptable to the offensive handgun, as well as M4A1, M16, SMAW-D and other small arms. As shown in FIG. 1, laser module 10 attaches to weapon 24 via interface chassis 23 which allows the operator to quickly move module 10 from one weapon platform to another.
Common leveling subplate assembly 84 (described in FIG. 3) is situated between interface chassis 23 and laser module 10 allows the system to be moved from one weapon to the next without needing any field adjustments to align laser located in the laser module, the flashlight module and, in the case of the M16/M4A1, in the handlegrips. Laser module 10 provides effective sighting of targets from 400-700 yards with both an infrared and visible laser.
Laser module 10 contains six control buttons for preselecting the following features: choice of visible, button 15 or infrared laser, button 13; choice of visible, button 18 or infrared flashlight illuminator, button 17; use of corresponding flashlight and laser together, with the laser dot at the center of the flashlight beam in either visible or infrared; and an adjustable laser beam pulse rate, button 16. Flashlight illuminator 12 is a separate unit with an independent power source which can be released from laser module 10. Wireless infrared remote control 43 (shown in FIG. 5) located on laser module 10 turns the power source for flashlight module 12 on and off. Flashlight module 12 can also be activated independently of laser module 10 for use in map reading, etc.
With laser module 10 attached without flashlight module 12, the offensive handgun 24 can be carried in a standard holster.
Six colored preselect buttons, identified above are inlaid into laser module 10. Buttons 13-18 are individually marked for easy identification of the function. The "IR LASER" and "VIS LASER", buttons 17 and 18, are for preselecting the infrared and visible red lasers respectively. The "OFF" button 14 shuts down the unit. The "IR FLASH" button 17 and "VIS FLASH" button 18 are for preselecting and the infrared and visible flashlight illuminators respectively and serve to activate flashlight module 12 power source when attached. To use a laser dot in conjunction with the corresponding flashlight, the operator depresses both the laser and illuminator preselect buttons.
"PULSE" button 16 is for programming the pulse rate of the laser beams. This feature allows the modification of both the infrared and red lasers from a constant beam to as few as 20 pulses per minute. Multiple shooters can distinguish their individual laser beams when jointly targeting the same area. During a forced entry or room sweep, individual shooters can identify their respective targets without the added confusion of trying to discern multiple laser beams.
Laser/flashlight activation is only possible when the visible or the infrared laser button or the visible or infrared flashlight button has been preselected. To activate the selected beam, the shooter depresses the activation buttons. Pressure on the activation buttons sends an infrared signal to laser module 10, activating the preselected features. The ambidextrous design allows activation by either the right or left hand. On offensive handgun 24, activation button 46 (shown in FIG. 6) is a pressure pad located below trigger guard. The activation signal is then carried via Kapton flex routing 45 to interface chassis 23. Chassis 23 has connectors 80 that connect to routing cable 45 so that laser module 10 can be turned on.
The location of the activation buttons will vary according to the particular weapon. For the M16/M4A1, the activation buttons are conveniently housed in the weapon handlegrip, ergonomically designed to accommodate the average grip. The activation switch on the SMAW-D is located on the back of the laser module.
The invention utilizes a 635 nm laser diode for visual sighting and an 830 nm laser for use with night vision equipment. Appropriate warning labels regarding laser danger are inlaid on the chassis to comply with federal regulations.
The effective range of a traditional open sight targeting system decreases dramatically in direct proportion to diminishing daylight. Targeting with a weapon equipped with the invention actually improves as darkness approaches. The bullet will hit the area illuminated by the laser dot, so there is no need to sight down the weapon or estimate the target. Laser aiming devises have been proven accurate for bullet placement in crowded areas and for multiple target acquisition. The invention allows the shooter to effectively fire the weapon from around most obstacles without becoming vulnerable to enemy fire.
The invention is powered by commercially available batteries, with 2 "AAAA" batteries located in the weapon grips for a rifle adaptation, 2 "AAAA" batteries in laser module 10, and 2 "AAA" batteries housed in flashlight module 12. The power sources provide up to 10 hours of continuous laser action and approximately several hours of continuous flashlight use. Battery life may be tested by depressing a sequence of buttons. If good, the red laser will emit a constant beam. A blinking beam indicates batteries are low and should be replaced. The battery test is independent of any beam pulse rates which the shooter may have programmed.
FIG. 2 is a front view of modular,laser apparatus mounted on a typical handgun along section line AA of FIG. 1. Chassis 23 is shown attached to weapon 24. Note that surface contour 72 of chassis 23 is dimensioned to fit the profile of the weapon. When chassis 23 is mounted on a different weapon, surface contour 72 or other aspects of the geometry of chassis 23 may change, however, the adjustment features described herein will be same of every version. In this manner, laser module 10 and its attached flashlight module 12 can be moved from weapon to weapon without requiring additional adjustments to sight in the weapon. As shown, infrared flashlight 29 is located on laser module 10 and visible flashlight 81 is a part of flashlight module 12. Infrared laser assembly 28 and visible laser assembly 27 are housed within laser module 10. While these are preferred positions, other variations and permutations are possible. For example, the infrared flashlight 29 could be located within flashlight module 12.
Laser assemblies 27 and 28 are adjusted using adjustments screws 26 and 30, respectively. Preferably, these screws adjust the lasers as previously disclosed by the inventor in prior applications. The preferred parts list and necessary electrical connections have also been previously described in great detail in the prior application.
Referring now to FIGS. 3, 3A through 3c, interface chassis 23 is shown with the associated leveling parts that enable the invention to be moved easily from weapon to weapon without the need for adjusting the sighting. The geometry of chassis 23 will change in accordance with the particular weapon that the chassis is installed on. However, the leveling assembly 84 are the same on every chassis 23, regardless of the weapon that it is installed on. In this manner, laser module apparatus 10 can be easily moved from weapon to weapon without the need for field adjustments in order to sight the weapon properly.
Locking bolt 20 secures chassis onto the weapon, in this case, pistol 24. Locking bolt 20 is screwed into a threaded opening that is already present in pistol 24, in this case, an H & K 9 mm, specially designed offensive handgun. For use with handguns not having this connection, it can be easily added to the weapon trigger guard.
Machined into chassis 23 are counterbores 54 and 55. Counterbores 54 and 55 are round. Preferably, the diameter of these counterbores is approximately 5/8 of inch. Subplate 25 is machined to have counterbores that correspond to counterbores 54 and 55, that is 54' and 55'. Counterbore 54' is substantially identical to counterbore 54. However, counterbore 55' is oval to permit side to side movement. Rubber washers 31 are selected to fit into counterbores 54, 54', 55, and 55'. O-ring 32 is selected to fit into groove 56 and groove 58. Groove 56 is machined into chassis 23 and groove 58 in subplate 25.
Leveling assembly 84 is held together via bolts 33 which are screwed into holes 64. Section 86 is the pivot point for the windage adjustment. Section 88 allows subplate 25 to move left to right to correct for windage. Adjustment screw 21 urges against tab 70, causing subplate 25 to move either left or right. Counterbore 55' and the corresponding slot 90 is oval to permit subplate 25 to easily slide relative to chassis 23.
To adjust elevation upward, screw in rear adjustment screws 22, wherein screws 22 are urged against adjustment plates 74. In turn, adjustment plates 74 compresses O-ring 32. Note that grooves 56 and 58 have a 45 degree shoulder which transforms the compressing into a vertical adjustment. To adjust the elevation downward, screw in forward adjustment screws 22.
To remove laser module 10 from subplate 25, the operator depresses release levers 19 and slides module 10 along dovetail 92. Levers 19 are locked around posts 76, held in place via spring 78.
Referring to FIG. 5, infrared emitter 43 in laser module 10 communicates with an infrared detector (not shown) in flashlight module 12 which activates flashlight module 12.
FIG. 7 is a side view of the modular laser apparatus mounted on a typical rifle. In this variation, chassis 23' has been modified to fit the weapon. As previously discussed, only the external geometry of chassis 23' has changed, the adjustment mechanism is identical. Rather than the pressure pad 46 of FIG. 6, infrared emitter 51 is located in the grip of the weapon which communicates with an infrared detector 52 in laser module 10. In this case, chassis 23' attaches to the weapon via thumbscrews 49 which engage picatinny rail 48. A detail of the attachment is shown in FIG. 8.
FIG. 9 shows laser module 10 attached SMAW/D weapon. As with the rifle connection, a picatinny rail attachment mechanism is used. Chassis 23" can be fitted with an optional hinged arrangement 100 to permit laser module 10 to be adjustment for gross elevation adjustments.
While there have been described what are at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and it is, therefore, aimed to cover all such changes and modifications as fall within the true spirit and scope of the invention.
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A laser sight that can be fits conventional handguns and rifles without requiring major modification of the weapons and yet fits within the profile of the weapons framework. The invention features a chassis containing an infrared and visible red laser than can be mounted in various position, depending on the weapon selected. For a 9 mm handgun, the chassis mounts on the front face of the muzzle. For a M-16, the chassis mounts on the weapon handle. The weapons factory installed hand grips are replaced by modified hand grips that contain the laser electronic controls, water proof activation switches, and power source. The hand grips are wired to the chassis via a flexible internal circuit tape in the case of the 9mm and waterproof quick disconnect cable for the M-16. The apparatus is designed to be used with commercially available batteries providing about 12 hours of operating time.
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DESCRIPTION
1. Field of Invention
This invention relates generally to a D/A converter (DAC) and more particularly to an entirely monolithic D/A converter which can be integrated on a single module without external components. Also, this invention relates to the use of such a converter in the implementation of an A/D (ADC) converter.
2. Prior Art
The D/A converter of this invention is of the type including weighted current sources, the number of which is equal to the number of bits of the words which can be processed by the converter. Each current source is associated to a switching means which receives a bit of the word to be converted as a control signal. According to the value of this bit, the current supplied by the corresponding source is directed either into a summing resistor or into a dump resistor.
D/A converters of this type are well known in the art as discussed or described in the following literature:
"A Complete Monolithic 10-b D/A Converter," by D. J. Dooley, published in the IEEE Journal of Solid State Circuits, Vol. Sc. 8, No. 6, December 1973.
See also: Electronics, April 4, 1974, page 125, which shows similar circuits.
The French patent application 75 27557 filed in France on Sept. 9, 1975, which corresponds to U.S. Pat. No. 3,961,326, also shows a typical prior art converter.
Both converters described in the above-indicated literature are of the type switching weighted currents either in a summing line or at the ground. These switching devices are under the control of the bits of the word to be converted. The Dooley converter, which can be fully integrated, can process only words of 10 bits (plus a sign bit), and it requires high supply voltages from ±12 volts to ±18 volts. The converter described in this reference can process words of 12 bits but it is a bit more cumbersome when operated in the 12 bit mode. In addition, it delivers only current. Consequently, if a voltage output is required, it is necessary to add an output amplifier which increases the overall dimensions of the unit and decreases the response speed. This amplifier is also provided in the Dooley converter, but it is integrated.
Both types of devices referred to above show response times and accuracies satisfactory for various applications, but these characteristics can prove insufficient for other applications. In particular, when a response time lower than a microsecond is required, they are inadequate.
OBJECTS OF INVENTION
Consequently, an object of this invention is to provide an improved and entirely monolithic digital/analog converter with very small overall dimensions.
Another object of this invention is to provide an improved and very accurate D/A converter having a short response time.
Another object of this invention is to provide an improved and inexpensive D/A converter.
Another object of this invention is to provide an improved D/A converter of a type particularly suited for application to an A/D converter of the successive approximation type.
BRIEF SUMMARY OF SPECIFICATION
The converter of this invention converts 12 bit words with a response time lower than one microsecond.
Owing to its particular design, it shows a very small linearity or convergence error which is equal, in the worst case, to half of the least significant bit for any group of eight consecutive bits. In addition, although it delivers a voltage output, its overall dimensions are reduced and it can be fully integrated on a module, the sides of which are 1.25 cm long. This advantage is obtained by substituting an output resistor of small dimensions integrated on the module for the output amplifiers which are generally used in the converters known in the art to transform a current output into a voltage output.
The converter of this invention includes twelve weighted current sources each of which is associated with one of twelve independent switching circuits. Each switching circuit is controlled by a bit of the word to be converted. The circuit controlled by the bit with the highest order is associated with the source providing the highest current. In the preferred embodiment of this invention, when the bit controlling a switching circuit is equal to 0, the current provided by the source associated with said switching circuit is fed into an output summing line. When said bit is equal to 1, the current is fed into a dump line.
The entire set of converter element pairs for the full complement of bit converters comprised of a current source and a switching circuit is divided into two groups of distinct structures. In effect, the accuracy of the currents corresponding to the bits with the highest orders is required to be very high since they contribute the largest currents in forming the output analog value. Consequently, the first group of current source/switching circuit pairs includes five very accurate current sources and five associated switching circuits of a first type. The second group of current source/switching circuit pairs includes at least seven less accurate current sources and the associated switching circuits of a second type which are therefore less complicated than the high accuracy ones. These are also less accurate, but are very fast and have small overall dimensions. This division of the current sources and switching circuit pairs into two groups ensures for each group the best compromise between the opposing requirement of high accuracy and speed but small overall dimensions. The continuity between the currents provided by the sources of the two groups and their respective scaling are ensured by three auxiliary sources. These are, respectively, a master source for monitoring and regulating the high order currents, high order image source and a master source for monitoring and regulating the low order currents. There are further provided two scaling circuits, a first one called the high order current scaling circuit and a second one called the low order current scaling circuit for controlling the value of the current provided by the low order current monitoring source from the current provided by the high order image source.
In addition, the converter includes a scaling and output circuit provided with an output resistor one terminal of which is connected to the output summing line, and further including a dump resistor, one terminal of which is connected to a dump summing line. The other terminals of these resistors are connected to a reference voltage V REF generated within the module. The output and dump resistors and scaling resistors connected to the circuit for scaling the high order currents are located close to one another to be perfectly matched. The ratios of these output, dump and scaling resistors are calculated to have the dynamics of the output signal within +V REF and -V REF . In this way, by modifying V REF , a two sector-multiplier can be provided. For this purpose, V REF is chosen equal to the positive multiplicand of the product to be carried out and the digital word applied to the converter is chosen equal to the desired multiplier.
In accordance with this invention, the converter includes two additional controls called "Force" and "Inhibit." The purpose of the "Force" control is to force the currents provided by all the sources into the output summing line regardless of whatever the converter input bit pattern may be. The purpose of the "Inhibit" control is to send all the currents provided by all the sources into the dump line regardless of whatever the converter input bit pattern may be.
These two controls are particularly advantageous when the converter of this invention is used in an A/D converter of the successive approximation type. The converters of this type generally include a comparator comparing the analog signal to be converted to successively generated reference levels. These reference levels can be generated by a D/A converter. According to the result of the comparison, a logic circuit successively applies bit patterns to which correspond various reference levels, to the converter inputs.
These devices are well known in the art, and it is possible to refer the reader to the book entitled, "Analog to Digital/Digital to Analog Conversion Technique," by David F. Hoeschele Jr., published by John Wiley and Sons, Inc., page 360.
To obtain a good accuracy, in particular around zero, it is known in the art to use two D/A converters. In the art, a first converter is used for generating the positive reference levels and a second one is used for generating the negative reference levels. When the D/A converter of the present invention is used in such an application, the "sign" bit of the bit pattern to be converted acts on the "Force" and "Inhibit" controls.
When the "sign" bit indicates a positive number, the "Inhibit" control acts on the second converter and the first one operates normally. When the "sign" bit indicates a negative number, the "Force" control acts on the first converter while the second converter operates normally.
These and other objects, advantages and features of the present invention will become more readily apparent from the following specification when taken in conjunction with the drawings.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a block diagram of the structure of the converter of this invention.
FIG. 2 illustrates the first group of high order current sources.
FIG. 3 illustrates the second group of low order current sources.
FIG. 4 shows the first group of switching circuits.
FIG. 5 shows the second group of switching circuits.
FIG. 6 illustrates the high order current scaling circuits.
FIG. 7 illustrates the low order current scaling circuits.
FIG. 8 diagrammatically shows the stabilized reference voltage generator.
FIG. 9 shows how two D/A converters should be connected for applying this invention in the construction of A/D converters.
DETAILED SPECIFICATION
The general principle of this invention will be described with reference to FIG. 1.
The converter includes weighted current sources, the number of which is equal to the number of bits in the words to be converted. As described herein, 12 word bits plus one more bit are used in the preferred embodiment of this invention. This 13th bit source is not compulsory and its function will be explained later. Only two of these sources are shown on the drawing, namely the one corresponding to the most significant bit, source 1-1 and the one corresponding to the least significant bit, source 1-12. The ratio of the currents provided by any two adjacent bit sources is equal to 2. Thus, if source 1-12 delivers a current unity I, source 1-1 delivers a current equal to I×2 11 .
A switching circuit 2 is associated with each current source. For example, circuit 2-1 is associated with source 1-1 and circuit 2-12 is associated with source 1-12.
Assembly 4 including the current sources and the switching circuits is divided into two groups 4-1 and 4-2. The first group 4-1 includes the five current sources and switching circuits corresponding to the first five high order bits. The second group 4-2 includes the seven current sources and switching circuits corresponding to the next seven low order bits, and a thirteenth source plus its associated switching circuit.
Each group includes additional current sources, namely a master source 5 for controlling the high order currents, a high order image source 6 and a master source 7 for controlling the low order currents. The values and functions of the currents provided by these sources will be indicated later.
The converter also includes two scaling circuits, the first one being comprised of circuits 8 and 12 and the second one of circuit 9. The function of circuit 8 is to transform the sum of the currents provided by the weighted sources into a voltage output from terminal 10. Circuits 9 is the low order current scaling circuit. Circuit 8 is connected, on the one hand, to master source 5 by line 11 through scaling circuit 12. The function of circuit 12 is to create a virtual ground at point 13 and to provide the scaling current to circuit 5. Circuit 8 is also connected through lines 14 and 15 to switching circuits 2-1 through 2-12. Circuit 8 includes four resistors R1, R2, R3 and R4. One of the terminals of resistors R3 and R4 is connected to conductors 14 and 15, respectively, and the other terminals of resistors R3 and R4 are connected in common to a node 16 to which is applied a reference voltage V REF provided by generator 17 located within the module.
Resistors R1 and R2 are mounted in parallel between nodes 13 and 16.
Low order current scaling circuit 9 is schematically shown on FIG. 1 as comprised of a current mirror including two transistors T1 and T2, the emitters of which are connected to two resistors R5 and R6, respectively. This circuit is shown in detail in FIG. 7. The second terminals of the resistors R5 and R6 are connected to node 16. Transistor T1 is diode mounted. Its base and its collector being connected together, and the base of transistor T1 is also connected to the base of transistor T2, the collector of which is connected to image source 6 through line 18. The collector of transistor T2 is also connected to master source 7 for controlling the low order bits through conductor 19. Consequently, the current carried by conductor 19 is equal to the current carried by conductor 18 and multiplied by the ratio R5/R6.
Circuit 12 is shown on FIG. 1 as including two transistors T3 and T4. Transistor T3 is diode mounted, its base and its collector being connected together. Its emitter is connected to ground and its collector is biased by a current equal to the current in T4. The base of transistor T3 is connected to the base of transistor T4, its collector is connected to source 5 and its emitter is connected to point 13. Consequently, the voltage across point 13 is equal to
-V.sub.BE T3 +V.sub.BE T4,
where V BE T3 and V BE T4 are the base/emitter voltages of transistors T3 and T4, respectively.
If transistors T3 and T4 match perfectly, the voltage across node 13 is equal to zero. It should be understood that this circuit includes scaling elements which will be described with reference to FIG. 6.
The operation of the circuit shown on FIG. 1 will now be described.
Each switching circuit 2-1 through 2-12 is provided with three control terminals. One of these terminals receives a bit of the word to be converted and the two other terminals receive the "Force and "Inhibit" controls. The purpose of these switching circuits is to direct the current provided by the associated source either to output summing line 14 or to dump line 15, according to the controls applied to the switching circuits. Switching circuit 2-1 is controlled by highest order bit MSB and circuit 2-12 is controlled by lowest order bit LSB.
If the "Force" and "Inhibit" controls are deconditioned, the switching circuits are responsive to the bits only. Consequently, the currents provided by the sources associated with switching circuits controlled by bits of value 0 are directed onto output line 14 and the currents provided by the sources associated with switching circuits controlled by bits of value 1 are directed onto dump line 15.
But, if the "Force" control is conditioned and the "Inhibit" control deconditioned, the currents provided by all the sources are directed onto line 14 whatever the value of the bits across the bit control terminals may be.
On the contrary, if the "Force" control is deconditioned and the "Inhibit" control conditioned, the currents provided by all the sources are directed onto dump line 15 whatever the value of the bits across the bit control terminals may be.
In the particular embodiment of this invention, source 5 provided for monitoring the high order sources is a current source. It delivers a current equal to the one of source 1-2, i.e., equal to I×2 10 . Sources 1-1 to 1-5 and sources 6 are slave sources of source 5 and provide the high order currents. Source 5 provides a current equal to the one of source 1-4, namely I S =I×2 8 .
Source 7 which is the master source for low order slave sources 1-7 to 1-12 is chosen to provide a current equal to the one of source 1-6. For this purpose, the resistance R5/R6 ratio is equal to 1/4, which makes the current on conductor 19 equal to I×2 8 ×2 -2 =I=2 6 . This corresponds to the value of the current provided by source 6.
It should be understood that the values of the currents provided by auxiliary sources 5, 6 and 7 are chosen for a particular embodiment of this invention and that these values can be modified provided that the values of the resistors forming the R1/R2 ratio are modified accordingly.
Resistance R3 is used for summing the currents since it is connected between a voltage +V REF and output 10. The maximum output voltage is equal to V REF when there is no bit current in output line 14. The resistances forming the R1/R4 ratio are chosen so that the dynamics of the output signal are equal to 2V REF . This gives a minimum output voltage -V REF when all the currents are summed in resistor R3.
It will be shown now that the resistor ratios give this output signal dynamic characteristic.
Circuit 12 applies high order currents to master source 5, a scaling current.
I.sub.CAL =[(R1+R2)/R1R2] V.sub.REF
by choosing R1=R2=R CAL , one has:
I.sub.CAL =2V.sub.REF R.sub.CAL
Output signal dynamics 2V REF is equal to R3×I S MAX, I S MAX being the maximum output current.
Consequently, since current I CAL has been chosen equal to the one provided by source 2-2, it is equal to current I S MAX divided by four. To make the dynamics of the output signal equal to 2V REF , it is, therefore, necessary to have R3=R CAL /4.
Resistor R4 is chosen equal to resistor R3, which allows the complementary current of the one summed into resistor R3 to be summed in resistor R4.
The voltages across the terminals of R3 and R4 are, therefore, always in opposite phase. This is used to accelerate the high order current switching.
With reference to FIG. 2, the following will describe how the sources of high order currents 5, 1-1 to 1-5 and 6, are embodied. These sources bear the same reference numbers as in FIG. 1.
All the sources but source 1-5 are comprised of identical cells. Weighting is performed by arranging several of these cells in parallel. For instance, source 1-1 includes eight cells, source 1-2 includes four cells, source 1-3 includes two cells and source 1-4 includes one cell. Auxiliary sources 5 and 6 provide currents equal to the ones of sources 1-2 and 1-4, respectively, and show the same structures as these sources.
As explained while referring to FIG. 1, source 5 is a master source which controls the weighted current sources connected thereto. A current I CAL is provided to master source 5 by circuits 8 and 12 of FIG. 1.
The components forming each cell bear the same references followed by a suffix corresponding to the current source in which they are incorporated. In the general description of a cell, only the reference number without suffix will be indicated. Each cell of sources 1-1 to 1-4 includes four transistors 22 to 25 and two resistors 26 to 27.
The transistors are arranged two by two, in parallel, i.e., transistors 22 and 23 are grouped. Their emitters, bases and collectors are interconnected. It is the same for transistors 24 and 25. Transistors 22 and 23 and transistors 24 and 25 are mounted in Darlington mode. To this end, the collectors of transistors 24 and 25 are connected to the collectors of transistors 22 and 23 in point M. The emitters of transistors 24 and 25 are connected to the bases of transistors 22 and 23 on the one hand, and to the emitters of the same transistors on the other hand, through a resistor 27. The connection point of the emitters of transistors 22 and 23 and of resistor 27 is connected to a power supply -V c through resistor 26. Each of the cells operates as a current generator.
The bases of transistors 24, 25 of all the cells forming current sources 5, 1-1 to 1-4 and 6 are interconnected by a conductor 30 biased by an appropriate voltage.
Since each source is comprised of several cells as indicated above, the cells of a source are mounted in parallel between point M and voltage -V c .
In source 5, circuit 12 of FIG. 1 applies a current I CAL to point M-5. Consequently, a current I CAL /4 flows in each of the cells forming source 5 since there are four cells in source 5.
Since the bases of transistors 24-5 and 25-5 are connected to the bases of the corresponding transistors in weighted sources 1-1 to 1-4 and 6, the base-emitter voltages between the bases of transistors 24-25 and the emitters of transistors 22 and 23 in the cells forming said weighted sources are equal to the corresponding base-emitter voltage in the cells of source 5. Consequently, the components of all the cells being perfectly matched, each cell contributes to apply a current equal to I CAL/4 to point M to which it is connected.
Source 1-5 uses the same structure and the same components as each of the cells described above, but the transistors are not dually mounted.
Source 1-5 includes only two Darlington mounted transistors 28 and 29. The base of transistor 29 is connected to the bases of transistors 22 and 24 of all the cells. The collectors of transistors 28 and 29 are connected to point M 1-5. The emitter of transistor 29 is connected to the base of transistor 28 on the one hand and to the emitter of the same transistor on the other hand through a resistor 27 1-5, the value of which is twice as high as the value of resistors 27 of the other cells. The common point of resistor 27 and the emitter of transistor 28 is connected to voltage -V c through a resistor 26 1-5, the value of which is also twice as high as the value of resistors 26 of the other cells.
In this way, since the transistors are not dually mounted and the values of the resistors are doubled in this cell, the current which is generated is equal to half the current generated by a cell constituting sources 1-1 to 1-4, 5 and 6.
Terminals 20 1-5, 20 1-1, 20 1-2, 20 1-3, 20 1-4, connected to points M of the corresponding sources, are the terminals which should be connected to the current switching circuits. Terminal 20-6 should be connected to circuit 9 by conductor 18 of FIG. 1.
At last, the arrangement of identical cells in parallel to form the various current sources is carried out on the physical circuit while respecting the symmetry center. Thus, when going over the series of side-by-side mounted cells and with the same orientation, there are found: a cell of source 1-1, then a cell of reference source 5, then a call of source 1-2, then a second cell of source 1-1 and so on. The single cell of source 1-5 is located on the symmetry center.
Thus, the values of the currents provided by the current sources will not respond to a linear variation of the physical characteristics of the cells.
A last advantage of the parallel arrangement of the cells should be indicated: the statistic dispersion of the ratios between the current values is reduced when the geometry of the cells has been chosen by another way at the optimum performance of the process. In other words, it increases the converter accuracy, theoretically in proportion to the square root of the number of cells.
Now, with reference to FIG. 3, the following will describe low order current source assembly 4-2. These sources bear the same reference numbers as on FIG. 1.
Source 1-7 includes two elementary current generators identical to the elementary current generator of sources 7 and 1-6. Therefore, it is comprised of two transistors 318 and 319, the emitters of which are connected to voltage -V c through two resistors 320 and 321. The collectors of transistors 318 and 319 are connected to terminal 20 1-7 which should be linked to switching circuit 2-7.
Source 1-8 includes only one elementary current generator comprised of transistor 322, the emitter of which is connected to voltage -V c through resistor 323. Its collector is connected to terminal 20 1-8 which should be linked to switching circuit 2-8.
Current sources 1-9 to 1-12 are weighted by a ladder resistor network R-2R and current generators identical to the generator of cell 1-8.
Source 1-9 includes transistor 324, the collector of which is connected to terminal 20 1-9 and the emitter to voltage -V c through a resistor 325 with the same value as the emitter resistors of the transistors of source 7 and 1-6 to 1-8.
It is the same for sources 1-10 to 1-12 which include transistors 326, 328 and 330 and resistors 327, 329 and 331.
Resistors 332, 333, 334, 335, the value of which is approximately equal to half the value of the emitter resistors, are mounted between the terminals not connected to the emitters of resistors 323 and 325, 325 and 327, 327 and 329, 329 and 331 to weight the currents provided by identical sources as known in the art, while taking the variations of the emitter-base voltage into account from one source to another.
A source 1-12' delivering a current equal to the one delivered by source 1-12 is provided. This additional source includes a transistor 336, the collector of which is connected to a terminal 20 1-12. The base is connected to the base of transistor 330 and the emitter is connected to the emitter of said transistor. This source is not used for operating in the D/A converter mode, but it is in the application of this converter to an A/D converter. Consequently, its function will be described with reference to FIG. 9.
The bases of the transistors of all the low order current sources are connected to an appropriate biasing voltage through a conductor 337.
Now, with reference to FIG. 4, the switching circuits provided for directing the high order currents will be described; namely, the switching circuits 2-1 to 2-5 of FIG. 1. Since all these switching circuits show the same structure, only circuits 2-1 and 2-2 for switching sources 1-1 and 1-2 are shown in FIG. 4. Circuits 2-3 to 2-5 are identical and should be connected as circuits 2-1 and 2-2 shown on the figure.
Also, switching circuits 2-1 and 2-2 show the same structure, except that in circuit 2-1 some transistors are doubled to avoid a too high current density in the junctions, which would decrease speed and reliability. Therefore, only one circuit will be generally described to make the drawing clearer, only the components of switching circuit 2-1 are referenced. The components of switching circuit 2-2 are shown but not referenced. When a particular component in a given switching circuit will be involved, it will be provided with the general reference number followed by the suffix corresponding to the switching circuit of which it is a part.
As shown in FIG. 4, each switching circuit includes a circuit 400 which directs the current delivered by a weighted current source connected to terminal 20 towards dump line 15. A circuit 401 receives the bit controls as well as the "Force" control and performs a level adaptation and transmits said controls to circuit 400. This circuit 401 is used for transferring the input controls to circuit 400 with a given high level and a given low level. The two levels considered vary slightly in accordance with the switch number. Their approximate values are of 1.9 volts and 0 volt measured between the transistor base as 422 and common potential V REF 2.
The levels are independent of the converter input logic levels insofar as they are compatible with the ones conventionally used in the TTL logic or the same.
A level shifting circuit 402 is common to all the switching circuits. This circuit is used for applying the "Inhibit" control and to make it active.
The converter input bits are applied to terminals 403-1, 403-2, . . . , 403-5 for the first five bits.
Circuit 401 includes a current source transistor 404, the emitter of which is connected to line 405 delivering voltage +V c through resistor 406. In the preferred embodiment of this invention, +V c is chosen equal to 5 volts. All the other voltage values which will be given later will reflect this particular value.
The base of current source transistor 404 is connected to a DC voltage, the value of which is 1.3 volts below V c , i.e., 3.7 volts in this example.
The collector of transistor 404 is connected to the emitter of a switching transistor 407. The collector of transistor 407 is connected to a DC voltage V REF 2 of approximately -4,6 volts through a resistor 408. Voltage V REF 2 is applied to resistors 408 of all circuits 401 2-1 to 401 2-5 through a conductor 409.
All the bases of transistors 407 2-1 to 407 2-5 are connected by a conductor 410 and all the bases of transistors 404 2-1 to 404 2-5 are connected through a conductor 411.
The bit control across terminal 403 is applied to the cathode of diode-mounted transistor 412, i.e., this cathode is comprised of the emitter of transistor 412, the base and collector of which are connected. The "Force" control applied to conductor 413 is applied to the cathode of a diode-mounted transistor 414 as transistor 412. The anodes of diode-mounted transistors 412 and 414 are connected to the emitter of transistor 407.
The collector of transistor 407 is connected to circuit 400 through conductor 415.
Circuit 402 provided for the "Inhibit" control shows a structure similar to the one of circuit 401. It includes a current source transistor 416, the emitter of which is connected to line 405 supplying voltage +V c through resistor 417. The base is connected to conductor 411 and its collector is connected to the emitter of a switching transistor 418. The base of transistor 418 is connected to conductor 410 and its collector is connected, through resistor 419, to conductor 409 supplying voltage V REF 2. Its collector is also connected to circuit 400 through conductor 420. The "Inhibit" control is applied to the cathode of a diode-mounted transistor 421, the base and collector of which are connected to the common point of the collector of transistor 416 and of the emitter of transistor 418.
The switching circuit includes a transistor 422 which is doubled in switch 2-1, i.e., it is associated with a transistor 422'. The bases, collectors and emitters of transistors 422 and 422' are interconnected. The base of transistor 422 is connected to the collector of transistor 407, its emitter is connected to the current source associated to terminal 20. The collector of transistor 422 is connected to dump line 15 of FIG. 1.
A Darlington assembly including two transistors 423 and 424 is connected between terminal 20 and output summing line 14. Transistor 424 is doubled in switch 2-1 and associated with a transistor 424' as noted previously. The collectors of transistors 423 and 424 are connected to line 14. The emitter of transistor 423 is connected to the base of transistor 424 and to the emitter of the same transistor through a resistor 425. The base of transistor 423 is connected to a conductor 426 which connects all the bases of transistors 423 2-1 to 423 2-5. Conductor 426 is connected to biasing voltage V POL . The base of transistor 427 doubled with a transistor 427' in circuit 400 2-1, is connected to the emitter of transistor 418. Therefore, it will respond to the "Inhibit" signal. Its collector is connected to line 15 and its emitter is connected to the current source associated with terminal 20.
The emitter of a transistor 428, which is doubled in circuit 400 2-1 with a transistor 428', is not connected. The capacitor of the base/collector junction is mounted between the base-emitter connection of transistors 424 and 423 respectively and the collectors of transistors 422 and 427.
Now the operation of a high level switching circuit will be described.
First of all, it will be assumed in a first case that the "Inhibit" and "Force" controls are inactive, i.e., the controls at the emitters of diode-mounted transistors 421 and 414 are at the low level, and at the high level, respectively. In these conditions, diode-mounted transistor 421 is conducting and diode-mounted transistor 414 is non-conducting.
Consequently, the current provided by transistor 416 goes through diode-mounted transistor 421. Transistor 418 is OFF as well as transistor 427. The "Inhibit" control has no effect.
Since diode-mounted transistor 414 is non-conducting, the current provided by transistor 404 is not subjected to the influence of the "Force" control but only to the influence of the bit on terminal 408.
Let us assume that the bit across terminal 403 is in a low level (<1.5 volts). Diode-mounted transistor 412 is conducting. Consequently, the current provided by transistor 404 goes into transistor 412 and transistor 407 is OFF. Then, transistor 422 is also inhibited. Due to the biasing voltage across the base of transistor 423, Darlington assembly 423-424 is conducting and the current delivered by the source connected to terminal 20 is directed towards output summing line 14.
Conversely, if the bit across terminal 403 is in a high level (>1.5 volts), transistor 412 is inhibited and the current of transistor 404 goes towards transistor 407 which becomes conducting. Consequently, the voltage across the base of transistor 422 increases and said transistor 422 becomes conducting so that its action overrides the one of transistors 423 and 424 and the current provided by the source connected to terminal 20 is directed towards dump summing line 15.
If the "Inhibit" control is active, i.e., in the high level and the "Force" control is inactive, the diode-mounted transistor 421 is non-conducting. Consequently, the current of transistor 416 goes through transistor 418 which becomes conducting. This makes transistor 417 conducting and its action overrides the one of transistors 422 and 423-424 so that the current delivered by the source connected to terminal 20 goes towards dump summing line 15.
If the "Force" control is active, i.e., low level, and the "Inhibit" control inactive, diode-mounted transistor 414 is conducting so that the current of transistor 404 is derived by this transistor. Transistor 407 is OFF as is transistor 422 so that the current delivered by the source connected to terminal 20 is transferred through Darlington assembly 423-424, to output summing line 14 whatever the control across terminal 403 may be.
Transistor 428 used as a capacitor, transfers an alternating current from line 15 to the base of transistor 424. This permits compensation for the alternating current received by the base of transistor 424 when any voltage change appears on the output summing line. This increases the switching speed by compensating for the Miller effect.
In the high order current switching circuits, a Darlington assembly 423-424 is used in the path directing the current to the output line in order to avoid current losses and to increase the gain. This increases the accuracy of the circuit. This is not necessary in the path directing the currents to the dump line since in this case the accuracy is less significant.
It should be understood that it is necessary to provide additional circuits in the converter to generate appropriate continuous voltage levels V POL (410), V POL (411), V POL (426) required for biasing the bases of the current source transistors of the level shifting circuit. 416, 404 2-1 and 404 2-5 as well as the switching transistors of this same circuit, namely 418, 407 2-1 to 407 2-5. These circuits are not shown since their embodiment is obvious for those skilled in the art.
Now the circuits provided for switching the low order currents will be described. In these circuits, the accuracy is less critical than in the circuits provided for switching high order currents since, as said before, said currents contribute a less significant part in forming the output signal. Consequently, switching circuits 2-6 to 2-12 and 2-12' are provided with the same basic structure as switching circuits 2-1 to 2-5, except that the Darlington assembly is replaced by an assembly provided with a single transistor in order to obtain a high switching speed in spite of the small value of the currents to be switched. In addition, the accuracy is very satisfactory and the overall dimensions of these circuits are reduced.
In FIG. 5 only switching circuits 2-6 and 2-10 are fully shown, as well as circuits 2-11, 2-12 and 2-12' which show some changes with respect to the previous ones. As in FIG. 4, there is shown only one of these circuits and the same reference numbers are used for the same elements in the circuits of FIGS. 5 and 4 except for the figures in the "hundred" positions.
As shown in FIG. 5, each circuit 2-6 to 2-12' includes a current directing circuut 500, a level control and shift circuit 501 and a circuit 502 common to the whole group of low level switching circuits, to apply and make the "Inhibit" control active.
The low order bits are applied to inputs 503-6 to 503-12.
Circuit 501 is provided with the same structure as circuit 401 of FIG. 4 and, therefore, it will not be described here.
Circuit 502 is also provided with the same structure as circuit 402 and it operates in the same way. The only difference is that resistor 519, similarly to resistor 419, is provided with three taps A, B, C from which are taken the controls generated from the "Inhibit" terminal acting on the bases of transistors 527 of circuits 500. The bases of transistors 527 2-6 to 527 2-10 are connected to tap A. The base of transistor 527 2-11 is connected to tap B and the bases of transistors 527 2-12 and 527 2-12' are connected to tap C.
In switching circuit 500 itself, the Darlington assembly of FIG. 4 is replaced by one or several transistors. For instance in circuit 500 2-6, the bases of four transistors bearing general reference number 530 are interconnected as well as the collectors and the emitters to form a structure having the same gain as the similar structures of circuits 2-7 and 2-8. The collectors are connected to output summing line 14, the emitters are connected to terminal 20 1-6 and the bases receive a biasing voltage generated from an additional circuit 531 on a line 532. Circuit 531 will be described later.
In circuit 500 2-7, element 530 2-7 consists of two coupled transistors only and in the other two structures 500 2-8 to 500 2-10, it consists of a single transistor, the base of which is also connected to line 532.
In circuit 500 2-11, the base of transistor 530 2-11 is connected to another biasing voltage through line 533, and in circuits 500 2-12 and 500 2-12', the bases of transistors 530 2-12 and 530 2-12' are connected to line 534.
Additional biasing circuit 531 is provided with a structure similar to structure 502, i.e., including two transistors 535 and 536. The emitter of transistor 535 is connected to line 405 through a resistor 537, its base is connected to line 411 and its collector is connected to the emitter of transistor 536 through a resistor 538. The bae of transistor 536 is connected to line 410 and its collector is connected to voltage V REF 2 through a resistor 539 provided with three taps D, E, F to which lines 532, 533 and 534, respectively, are connected.
As in the circuits provided for switching the currents corresponding to the bits of high order, the signals used to control circuits 500 should have a well-defined amplitude to make sure that the ratio of the currents in the "ON" and "OFF" states for each bit current is correct in the output line.
In the circuit of FIG. 5, the biasing voltages across the bases of transistors 530 2-6 to 530 2-10 are the same as are the controls acting on the bases of transistors 527 2-6 to 527 2-10. In these transistors, the bit controls on the bases of 522 2-6 to 522 2-10 show amplitudes of 380 mV approximately and the biasing voltage across the bases of 530 2-6 to 530 2-10 is 190 mV above V REF 2.
In circuit 500 2-11, the amplitude of the control applied to the base of transistor 522 2-11 is of 330 mV and the biasing voltage across the base of 530 2-11 is 160 mV above V REF 2.
In circuits 500 2-12 and 500 2-12', the amplitude of the control signal on the base of transistors 522 2-12 and 522 2-12' is of 260 mV and the biasing voltage on the bases of 530 2-12 and 530 2-12' is 130 mV above V REF 2.
It should be understood that these values are given only as an example and that an additional control circuit not shown here is provided to allow the level shifting circuits to generate the appropriate voltages. This can be ensured by monitoring the voltages on lines 410 and 411.
Now circuits 8, 12 and 9 provided for calibrating the high order currents will be described in detail.
Circuits 8 and 12, one function of which consists in calibrating the high order currents, are used to give a determined current value to the master source controlling the high order currents. In fact, the output current of this circuit should be exactly equal to the input current.
In circuit 8 shown in FIG. 1, output resistors R3 and R4 are chosen equal to 1 kilo-ohm and both calibrating resistors R1 and R2 have a value of 4 kilo-ohms each. As shown above, the resistance ratio defines the dynamic range of output voltage (+V REF , -V REF ).
Output resistor R3 is connected to the output summing lines and the calibrating block 12 of the high order sources through line 11 (FIG. 1).
Circuit 12 shown in FIG. 6 is a current mirror mainly comprised of two transistors 601 and 602. The emitter of transistor 602 is ground connected through terminal 603 and the emitter of transistor 601 is connected to line 11 of FIG. 1. The bases of transistors 601 and 602 are interconnected. The base of transistor 604 is connected to the bases of transistors 601 and 602, the emitter is connected to the ground, the collector is connected to the emitter of a transistor 605, the collector of which is connected to voltage -V c .
The current flowing in line 11 is the calibrating current. It should be, on the one hand, equal to V REF (R1+R2)/R1 R2, which requires the emitter of transistor 601 to be virtually grounded and, on the other hand, fully transferred towards the high order calibrating source through line 622.
The first of these conditions is fulfilled by applying the same operating conditions to transistors 601 and 602, which is obtained by making resistors, 613 and 621 connected to the collectors of these transistors, equal and by making the current of the high order calibrating source, circuit 5 of FIG. 2, and the current of an auxiliary source comprised of transistors 611 and 612 associated with resistors 614 and 615, approximately equal. The collectors of transistors 611 and 612 are connected to resistor 613, the base of transistor 611 is connected to the emitter of transistor 612 and resistor 614 is connected to the emitter of transistor 612 and to the emitter of transistor 611. The emitter of transistor 611 is connected to voltage -V c through resistor 615.
To make the current of the calibrating source and the current of auxiliary source 611, 612 equal, it is sufficient to choose values for resistors 614 and 615 which are four times lower than the ones of resistors 27-5 and 26-5 of FIG. 2.
The second condition is ensured by transistor 605. The base of transistor 605 is connected to resistor 621, and the base current is equal to the one of transistor 601 since source transistor 604 operates with the same current as transistor 601. Thus, the base current of transistor 601 lost in line 11 is exactly balanced by the base current of transistor 605 applied by line 622.
Transistor 606 with its collector connected to ground, its base connected to the base of transistor 605 and its emitter connected to line 30 (FIG. 2) is an error amplifier acting on conductor 30 common to all the high order sources to force a current into source 5 which is equal to the current applied to line 11.
A circuit including two transistors 607 and 608 and a resistor 610 is used for recouping the current loss in the current directing circuit corresponding to bit 2. These transistors are arranged as follows: their collectors are connected to line 11, the base of transistor 607 is connected to ground and its emitter is connected to the base of transistor 608. The emitter of transistor 607 is also connected to the emitter of transistor 608 through resistor 610. The emitter of transistor 608 is connected to the collector of a transistor 623, the base of which is connected to the collector of transistor 601 and the emitter is connected to the base of transistor 606 and to resistor 621.
The base of transistor 616 is connected to the collector of transistor 602, the collector is connected to ground and the emitter is connected to the collectors of transistors 611 and 612. The bases of transistors 602 and 604 are also connected to ground through a resistor 617 and to voltage -V c through a transistor 618 and a transistor 619. The collector of transistor 618 is connected to the base of transistor 602, the emitter is connected to the emitter of transistor 619, the collector of which is connected to voltage -V c . The base of transistor 619 is connected to the common point of the collectors of transistors 611 and 612 and of the emitter of transistor 616.
Transistor 618 is biased by a circuit including a resistor 610 and a Zener diode mounted transistor 624, i.e., mounted with its base and collector interconnected. The base of transistor 618 is ground-connected through resistor 620 and to the emitter of transistor 624, the collector of which is connected to voltage -V c .
Now the circuit for calibrating low order currents will be described while referring to FIG. 7.
This circuit includes a current mirror comprised of transistors 701 and 702, the emitters of which are connected to voltage +V REF through four resistors 703 to 706 mounted in parallel and a resistor 707, respectively. Since these resistors are provided with the same value, the emitter resistor of transistor 701 is four times smaller than the emitter resistor of transistor 702.
The bases of transistors 701 and 702 are interconnected to point 708. Point 708 is connected to voltage +V REF through a resistor 700 and to voltage -V c through a transistor 709, the collector of which is connected to point 708 and the emitter. Point 708 is also connected to the emitter of transistor 710, the collector of which is connected to voltage -V c . The base of transistor 710 is connected to terminal 20-6. Transistor 709 is biased by a circuit including a resistor mounted between the base of transistor 709 and voltage +V REF and Zener diode-mounted transistor 714. The emitter of transistor 714 is connected to the base of transistor 709 and the base and the collector are connected to voltage -V c .
The collector of transistor 701 is connected to terminal 20-6 of FIG. 3 through a resistor 711. It is also connected to the base of a transistor 712, the collector of which is connected to the emitter of transistor 701 and the emitter to terminal 20-6.
In this second branch of the circuit, the collector of transistor 702 is conected to terminal 20-7 through a resistor 718. It is also connected to the base of a transistor 714, the collector of which is connected to the emitter of transistor 702 and the emitter of which is connected to terminal 20-7.
The collector of transistor 719 is connected to voltage +V REF . The base of transistor 719 is connected to terminal 20-7 and the emitter is connected to a circuit including two transistors 720 and 721. The collector of transistor 720 is connected to its base on the one hand and to the collector of transistor 721 on the other hand. The emitter of transistor 720 is connected to the base of transistor 721, and the emitter of transistor 721 is connected to a terminal 722 to which conductor 337 of FIG. 3 is to be connected.
Transistor 701 and 702 operate with the same base-emitter voltages. Since the resistor equivalent to resistors 703 to 706 is four times smaller than resistor 707, the current flowing towards terminal 20-7 is four times smaller than the one flowing towards terminal 20-6.
Transistor 719 and diode-mounted transistors 710 and 721 form an amplifier which makes the current provided to master source 7 equal to one quarter of the current provided by the source corresponding to bit 4.
After the description of the main elements of the converter, one will proceed to the description of the circuit generating level V REF while referring to FIG. 8. This block provides a temperature stabilized output voltage which, in this embodiment, is chosen equal to 2.5 volts. It is supplied from a voltage +V c of +5 volts. Thus, it can be noted that power supply voltages +V c and -V c are relatively lower than in the devices of the prior art, which gives a particular advantage to the converter of this invention.
This circuit includes cell 801 to provide the reference voltage, starting circuit 802, output amplifier 803 and current mirror 804.
Circuit 801 includes transistors 806 to 812 and resistors 813 to 817. This circuit provides a voltage to node 818 which depends on the current flowing through transistors 811 and 812. For a particular value of this current, this voltage is stable with respect to temperature.
Transistors 807 and 808 are matched, their bases are connected as well as their emitters and collectors. It is the same for transistors 809 and 810. The collectors of transistors 807 and 808, as well as the collectors of transistors 809 and 810 are connected to point 818 through resistors 814 and 815, respectively. The emitters of transistors 807 and 808 are directly connected to the ground and the ones of transistors 809 and 810 are connected to the ground through resistor 816.
The collector of transistor 806 is connected to point 818, the base is connected to the collectors of transistors 807 and 808 and the emitter is connected to the bases of transistors 807 and 808, and to the ground through resistor 813. The collectors of transistors 811 and 812 are commonly connected in 819. The base of transistor 811 is connected to the collector of transistors 809 and 810, its collector is connected to the base of transistor 812 and its emitter is connected to the ground through resistor 817. The emitter of transistor 812 is also connected to the ground.
This circuit operates as follows. Reference voltage V REF at point 818 is the sum of two voltages generated as follows.
A first voltage V1 is the sum of the base-emitter voltage of transistors 811 and 812. The current going through these transistors is kept constant and approximately equal to 0.5 mA according to the temperature.
Second voltage V2 is the voltage drop in resistor 815. The current going through this resistor is practically the same as the one going through resistor 816. Resistor 815 is chosen equal to eighteen times the value of resistor 816, so that voltage V R815 across the terminals of resistance 815 is eighteen times greater than voltage V R816 across the terminals of resistor 816.
i.e. V R815 =18 V R816 .
V R816 is the differential base-emitter voltage between matched pairs of transistors 807, 808 and 809, 810.
The current ratio in transistors 807, 808 and 809, 810 is also kept constant in accordance with the temperature. These currents are defined by resistors 814 and 815.
The same voltage appears across the terminals of resistors 814 and 815 connected to transistors 807, 808 and 809, 810, namely.
V.sub.REF -2V.sub.DIODE
Since resistors 814 and 815 are values interrelated with a ratio of 13, there is the same ratio for the currents flowing through transistors 807, 808 and 809, 810.
Therefore, one has
V.sub.R816 =(KT/q) log.sub.e (I.sub.e1 /I.sub.e2)
K being the Boltzmann constant,
T being the temperature,
q being the electron charge,
I e1 being the emitter current of transistors 807, 808
I e2 being the emitter current of transistors 809, 810.
According to the diode law, V R816 is of 66 mV approx. at 25° C. and increases by 0.22 mV for every Celsius degree.
V R815 is eighteen times greater than V R816 , i.e., equal to 1.19 volts at 25° C. plus 3.9 mV for every Celsius degree.
For a constant current through transistors 811 and 812, voltages V1 V2 compensate in temperature so that reference voltage V REF across point 818 is constant.
The constant current through transistors 811 and 812 is provided by circuit 804 which includes a current generator and a current mirror.
The current generator includes two transistors 820 and 821 mounted in series with a resistor 822. The base of transistor 820 is connected to point 818 and its emitter is connected to the collector of transistor 821. The collector of transistor 821 is connected to its base and its emitter is connected to the ground through resistor 822.
The collector current of transistor 820 is reflected by a current mirror in the collector path of transistors 811 and 812.
The current mirror includes four transistors 823 to 826 and four resistors 827 to 830.
Transistors 823 and 824 are mounted in the collector path of transistor 820. The emitter of transistor 823 is connected to the collector of transistor 820, its collector is connected to voltage +V c through resistor 827. The emitter of transistor 824 is connected to the collector of transistor 823, its collector is connected to the base of transistor 823 on the one hand and to the emitter of transistor 823 through resistor 828 on the other hand.
Transistors 825 and 826 are similarly mounted in the collector path of transistors 811 and 812. The bases of transistors 824 and 825 are interconnected through conductor 831. The biasing circuit of the current mirror comprises resistor 832, a terminal of which is connected to voltage +V c and the second terminal of which is connected to conductor 831, and transistor 833. The emitter of transistor 833 is connected to conductor 831, its collector is connected to the ground and its base is connected to the emitter of transistor 823.
Output amplifier 803 provides the feedback required for regulating voltage. It includes three transistors 834, 835, 836 and a resistor 837. The collector of transistor 834 is connected to voltage +V c , the emitter is connected to point 818 and the base is connected to the common point of the collector of transistor 835 and of the emitter of transistor 836. The emitter of transistor 835 is connected to voltage +V c through resistor 837, and its base is connected to the bases of transistors 825 and 824. The base of transistor 836 is connected to the emitter of transistor 826 in the current mirror and its collector is connected to the ground.
Transistors 835 and 836 reduce the current mirror charge. In addition, transistors 834 and 836 are arranged to set the current mirror output voltage to 2.5 volts.
Starting circuit 802 allows the regulation on starting to be obtained. It includes four transistors 838 to 841 and resistors 842 to 845. The collector of transistor 838 is connected to voltage +V c , its emitter is connected to the base of transistor 834 and its base is connected to the common point of resistors 842 and 843. Transistors 839 and 840 are diode-mounted and their collectors and bases are connected. In addition, the collector of transistor 839 is connected to the collector of transistor 840 and the common point is connected to point 818.
The emitter of transistor 839 is connected to voltage +V c through serially-mounted resistors 843 and 842. The emitter of transistor 840 is connected to the base of transistor 841 on the one hand and to its emitter through resistor 844 on the other hand. The collector of transistor 841 is connected to the emitter of transistor 839 and its emitter is connected to the ground through resistor 845.
On starting, when V REF =0 and V c ≧3.8 volts, a current goes through transistors 838 and 834 and in the charge connected to point 819. No current is applied to transistors 840 and 841. The potential across point 818 increases up to 1.6 volts at 25° C. and then transistor 841 is OFF. When the voltage at point 819 reaches the operating point above 2 volts, transistor 841 becomes conducting, which brings the voltage across the base of transistor 838 to a value close to the voltage across the base of transistor 841. Transistor 838 is inhibited and the starting circuit is inactive. Diode-mounted transistors 839 and 840 maintain transistor 841 unsaturated.
FIG. 9 schematically shows two D/A converter modules which can be used for generating reference levels for an A/D converter of the type described in the book entitled, "Analog to Digital and Digital to Analog Conversion Techniques," given as a reference at the beginning of this specification.
In this figure, there are shown only the connections which enable the circuits described in FIGS. 1 to 8 to be used in an A/D converter.
Two modules are provided in this application, module 901 for converting the positive numbers and module 902 for converting the negative numbers.
In these modules, each portion 903 and 904 includes circuits 4-1 and 4-2, 12, 9, 17 of FIG. 1. The bits of the words to be converted are applied to the modules through bit controls 905 and 906 and the sign bits act on the FORCE or INHIBIT controls in a way to be described later.
The elements included in circuit 8 of FIG. 1, namely calibrating resistors R1 and R2, as well as output resistor R3, are shown in each module since these elements are interconnected to ensure the continuity around zero.
In effect, it was previously shown that the calibrating currents depend on reference voltage V REF and on the values of the calibrating resistors. Consequently, it is to be ascertained that the calibrating currents in modules 901 and 902 are strictly equal to avoid any discontinuity of the conversion around zero. This is ensured by connecting modules 901 and 902 as shown in FIG. 9.
In this figure, elements R1, R2, R3, 10, 11 and 14 of FIG. 1 bear a suffix 1 in module 901 and a suffix 2 in module 902. Reference voltage V REF is called V1 in module 901 and V2 in module 902.
As shown in FIG. 9, resistor R1-1 is connected to line 11-1, on the one hand and to resistor R2-2, on the other hand. In the same way, resistor R1-2 is connected to line 11-2 on the one hand and to line R2-1 on the other hand. Output terminals 10-1 and 10-2 are interconnected to an output 907 from which is taken the output signal of the set comprised of the two modules.
In this way, the calibrating current of module 901 is equal to V1/R1-1+V2/R2-2 and the calibrating current of module 902 is equal to V2/R1-2+V1/R2-1. Since in a same module, resistors R1 and R2 are matched and, therefore, perfectly equal, it can be seen that the calibrating currents in conductors 11-1 and 11-2 are equal.
For converting a positive number, the bits of which except the sign bit are applied to controls 905 and 906, module 901 is active. The INHIBIT and FORCE controls are inactive and module 901 operates normally. Module 902 is inhibited, i.e., in this module, the control is inactive, which means that no current flows from this module to output 907.
For converting a negative number, module 902 is active. The INHIBIT and FORCE controls are inactive and the FORCE control of module 901 is active which means that all the currents of this module flow to output 907.
For converting a negative number, module 902 is active. The INHIBIT and FORCE controls are inactive and the FORCE control of module 901 is active which means that all the currents of this module flow to output 907.
For this purpose, if it is assumbed that the binary numbers to be converted are expressed in the two's complement code, the signal bit of the bit patterns applied to inputs 905 and 906 is used to act on the FORCE and INHIBIT controls.
In module 901, the inverse of the sign bit is applied to the FORCE control and the INHIBIT control is high. In module 902, the inverse of the signal bit is applied to the INHIBIT control and the FORCE control is high.
Consequently, the maximum output voltage will be obtained when no current flows to output 907 and the minimum output voltage will be obtained when all the currents flow to the output. Since output resistors R3-1 and R3-2 are connected to terminal 907, the dynamic range of the output signal will be, therefore again, equal to 2V REF .
Now the function of current source 1-12' and of its associated switching circuit 2-12' will be explained. In effect, this source ensures a particular function in this application. It prevents the analog values corresponding to bit patterns 0 000000000000 and 1 111111111111 from being similar.
As to pattern 0 000000000000, module 901 will be active and all the current sources and this module feed resistor R3-1, module 902 is inactive and there is no current source in this module to feed resistor R3-2. Therefore, an output at the 0 volt level is obtained.
As to pattern 1 111111111111, all the sources of module 901 feed resistor R3-1 and there is no source in module 902 to feed resistor R3-2. Consequently, without any additional source 1-12' in module 901, the same analog value 0 would be obtained for this pattern, which is not desired. Therefore, since in this case and for all the negative numbers applied to modules 901 and 902, source 1-12' of module 901 delivers a current and an additional current equal to the current corresponding to the less significant bit is provided to resistor R3-1.
This source which is not absolutely necessary to perform a normal digital/analog conversion is provided on the module to make the application to the A/D converter possible without modifying the modules.
The following table gives the analog values corresponding to the bit inputs in the case of thw two's complement code, while assuming that the elementary current unit corresponding to the less significant bit generates a voltage step equal to 0.635 millivolt.
__________________________________________________________________________ Number ofSign BitBit Bit Bit Bit Bit Bit Bit Bit Bit Bit Bit Bit current Outputbit 1 2 3 4 5 6 7 8 9 10 11 12 13 units voltage__________________________________________________________________________0 1 1 1 1 1 1 1 1 1 1 1 1 1 VREF -0 1 1 1 1 1 1 1 1 1 1 1 0 2 VREF -0,635mV0 1 1 1 1 1 1 1 1 1 1 0 1 3 VREF -1,27mV0 1 1 1 1 1 1 1 1 1 1 0 0 4 VREF -1,90mV0 0 0 0 0 0 0 0 0 0 0 1 0 2.sup.12 - 2 +1,27mV0 0 0 0 0 0 0 0 0 0 0 0 1 2.sup.12 - 1 + 0,635mV0 0 0 0 0 0 0 0 0 0 0 0 0 2.sup.12 OV1 1 1 1 1 1 1 1 1 1 1 1 1 2.sup.12 + 1 -0,635mV1 1 1 1 1 1 1 1 1 1 1 1 0 2.sup.12 + 2 -1,27mV1 1 1 1 1 1 1 1 1 1 1 0 1 2.sup.12 + 3 -1,90mV1 0 0 0 0 0 0 0 0 0 0 1 0 2.sup.13 - 2 -VREF +0,635mV1 0 0 0 0 0 0 0 0 0 0 0 1 2.sup.13 - 1 -VREF1 0 0 0 0 0 0 0 0 0 0 0 0 2.sup.13 -VREF -0,635mV__________________________________________________________________________
In the preceding description of FIG. 9, the inverse of the sign is applied to the FORCE and INHIBIT controls of modules 901 and 902, respectively. It is obvious that the circuits required to perform the sign inversion can be provided in the module, in which case the sign can be directly applied to the FORCE and INHIBIT controls.
If the inverters are integrated in the module, it is obvious that the levels which should be applied to the module to make the FORCE and INHIBIT controls active or inactive will be the inverse of the ones given in the description of FIGS. 4 and 5.
The converter was described as allowing 12-bit words to be converted, but it is obvious that its structure can be readily adapted for converting N-bit words. For this purpose, the number of weighted current sources should be changed and the numbers n and m of sources in the first group and in the second group should be chosen to obtain the best accuracy/overall dimension ratio.
While the 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.
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This invention relates to a digital to analog converter in general and specifically to unitary or monolithic miniature digital to analog converters designed to be fully embodied on a single one-half inch module without requiring external converter components. The digital to analog converter comprises n binary current sources and n two-way switches, n being the number of input word bits. Each switch is driven by a bit input and its function is to steer the current of the corresponding source either into a summing line for output or into a dump line. A primary feature of this converter is the separation of all individual bit converter structures comprising a current source and steering means into two different groups. In this scheme, a first group of converter structures is used to convert the high order bits and a second group of converter structures is used to convert the low order bits. This arrangement allows the provision of different types of current sources for the different converter structures depending upon the accuracy required for each current source. Control inputs are provided for acting upon the steering means to generate reference levels to which an input analog signal in an A/D converter is compared. By this technique, the D/A converters of the present invention may be utilized in A/D encoding and an improved conversion accuracy of about zero is provided.
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[0001] This application is a continuation and claims the benefit under 35 USC 120 of U.S. application Ser. No. 09/267,498 filed by Sweetland et al. on Mar. 12, 1999.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The invention relates generally to electrical downhole tools which are employed for various downhole oil-field applications, e.g., firing shaped charges through a casing and setting a packer in a wellbore. More particularly, the invention relates to a pressure-actuated downhole tool and a method and an apparatus for generating pressure signals which may be interpreted as command signals for actuating the downhole tool.
[0004] 2. Background Art
[0005] Electrical downhole tools which are used to perform one or more operations in a wellbore may receive power and command signals through conductive logging cables which run from the surface to the downhole tools. Alternatively, the downhole tool may be powered by batteries, and commands may be preprogrammed into the tool and executed in a predetermined order over a fixed time interval, or command signals may be sent to the tool by manipulating the pressure exerted on the tool. The downhole pressure exerted on the tool is recorded using a pressure gage, and downhole electronics and software interpret the pressure signals from the pressure gage as executable commands. Typically, the downhole pressure exerted on the tool is manipulated by surface wellhead controls or by moving the tool over set vertical distances and at specified speeds in a column of fluid. However, generating pressure signals using these typical approaches can be difficult, take excessively long periods of time to produce, or require too much or unavailable equipment. Thus, it would be desirable to have a means of quickly and efficiently generating pressure signals.
SUMMARY OF THE INVENTION
[0006] In general, in one aspect, a hydraulic strain sensor for use with a downhole tool comprises a housing having two chambers with a pressure differential between the two chambers. A mandrel disposed in the housing is adapted to be coupled to the tool such that the weight of the tool is supported by the pressure differential between the two chambers. A pressure-responsive member in communication with one of the chambers is arranged to sense pressure changes in the one of the chambers as the tool is accelerated or decelerated and to generate signals representative of the pressure changes.
[0007] Other aspects and advantages of the invention will be apparent from the following description and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] [0008]FIG. 1 is a schematic illustration of a downhole assembly for use in performing a downhole operation in a wellbore.
[0009] [0009]FIG. 2 is a detailed view of the hydraulic strain sensor shown in FIG. 1.
DETAILED DESCRIPTION
[0010] Referring to the drawings wherein like characters are used for like parts throughout the several views, FIG. 1 depicts a downhole assembly 10 which is suspended in a wellbore 12 on the end of a conveyance device 14 . The conveyance device 14 may be a slickline, wireline, coiled tubing, or drill pipe. Although running the downhole assembly into the wellbore on a slickline or wireline is considerably faster and more economical than running on a coiled tubing or drill pipe. The downhole assembly 10 includes a hydraulic strain sensor 16 and a downhole tool 18 which may be operated to perform one or more downhole operations in response to pressure signals generated by the hydraulic strain sensor 16 . For example, the downhole tool 18 may be a perforating gun which may be operated to fire shaped charges through a casing 19 in the wellbore 12 .
[0011] The hydraulic strain sensor 16 includes a sealed chamber (not shown) which experiences pressure changes when the downhole tool 18 is accelerated or decelerated and a pressure-responsive sensor, e.g., a pressure transducer (not shown), which detects the pressure changes and converts them to electrical signals. The hydraulic strain sensor 16 communicates with the downhole tool 18 through an electronics cartridge 20 . The electronics cartridge 20 includes electronic circuitry, e.g., microprocessors (not shown), which interprets the electrical signals generated by the pressure transducer as commands for operating the downhole tool 18 . The electronics cartridge 20 may also include an electrical power source, e.g., a battery pack (not shown), which supplies power to the electrical components in the downhole assembly 10 . Power may also be supplied to the downhole assembly 10 from the surface, e.g., through a wireline, or from a downhole autonomous power source.
[0012] Referring to FIG. 2, the hydraulic strain sensor 16 comprises a hydraulic power section 22 and a sensor section 24 . The hydraulic power section 22 includes a cylinder 26 . A fishing neck 28 is mounted at the upper end of the cylinder 26 and adapted to be coupled to the conveyance device 14 (shown in FIG. 1) so that the hydraulic strain sensor 16 can be lowered into and retrieved from the wellbore on the conveyance device. With the fishing neck 28 coupled to the conveyance device 14 , the hydraulic strain sensor 16 and other attached components can be accelerated or decelerated by jerking the conveyance device. The fishing neck 28 may also be coupled to other tools. For example, if the conveyance device 14 is inadvertently disconnected from the fishing neck 28 so that the hydraulic strain sensor 16 drops to the bottom of the wellbore, a fishing tool, e.g., an overshot, may be lowered into the wellbore to engage the fishing neck 28 and retrieve the hydraulic strain sensor 16 . The fishing neck 28 may be provided with magnetic markers (not shown) which allow it to be easily located downhole.
[0013] A mandrel 30 is disposed in and axially movable within a bore 32 in the cylinder 26 . The mandrel 30 has a piston portion 34 and a shaft portion 36 . An upper chamber 38 is defined above the piston portion 34 , and a lower chamber 40 is defined below the piston portion 34 and around the shaft portion 36 . The upper chamber 38 is exposed to the pressure outside the cylinder 26 through a port 42 in the cylinder 26 . A sliding seal 44 between the piston portion 34 and the cylinder 26 isolates the upper chamber 38 from the lower chamber 40 , and a sliding seal 46 between the shaft portion 34 and the cylinder 26 isolates the lower chamber 40 from the exterior of the cylinder 26 . The sliding seal 44 is retained on the piston portion 34 by a seal retaining plug 48 , and the sliding seal 46 is secured to a lower end of the cylinder 26 by a seal retaining ring 50 .
[0014] The sensor section 24 comprises a first sleeve 52 which encloses and supports a pressure transducer 54 and a second sleeve 56 which includes an electrical connector 58 . The first sleeve 52 is attached to the lower end of a connecting body 62 with a portion of the pressure transducer 54 protruding into a bore 64 in the connecting body 62 . An end 66 of the shaft portion 36 extends out of the cylinder 26 into the bore 64 in the connecting body 62 . The end 66 of the shaft portion 26 is secured to the connecting body 62 so as to allow the connecting body 62 to move with the mandrel 30 . Static seals, e.g., o-ring seals 76 and 78 , are arranged between the connecting body 62 and the shaft portion 36 and pressure transducer 54 to contain fluid within the bore 64 .
[0015] The second sleeve 56 is mounted on the first sleeve 52 and includes slots 80 which are adapted to ride on projecting members 82 on the first sleeve 52 . When the slots 80 ride on the projecting members 82 , the hydraulic strain sensor 16 moves relative to the downhole tool 18 (shown in FIG. 1). A spring 82 connects and normally biases an upper end 84 of the second sleeve 56 to an outer shoulder 86 on the first sleeve 52 . The electrical connector 58 on the second sleeve 52 is connected to the pressure transducer 54 by electrical wires 88 . When the hydraulic strain sensor 16 is coupled to the electronics cartridge 20 (shown in FIG. 1), the electrical connector 58 forms a power and communications interface between the pressure transducer 54 and the electronic circuitry and electrical power source in the electronics cartridge.
[0016] The shaft portion 36 has a fluid channel 90 which is in communication with the bore 64 in the connecting body 62 . The fluid channel 90 opens to a bore 92 in the piston portion 34 , and the bore 92 in turn communicates with the lower chamber 40 through ports 94 in the piston portion 34 . The bore 92 and ports 94 in the piston portion 34 , the fluid channel 90 in the shaft portion 36 , and the bore 64 in the connecting body 62 define a pressure path from the lower chamber 40 to the pressure transducer 54 . The lower chamber 40 and the pressure path are filled with a pressure-transmitting medium, e.g., oil or other incompressible fluid, through fill ports 96 and 98 in the seal retaining plug 48 and the connecting body 62 , respectively. By using both fill ports 96 and 98 to fill the lower chamber 40 and the pressure path, the volume of air trapped in the lower chamber and the pressure path can be minimized. Plugs 100 and 102 are provided in the fill ports 96 and 98 to contain fluid in the pressure path and the lower chamber 40 .
[0017] When the hydraulic strain sensor 16 is coupled to the downhole tool 18 , as illustrated in FIG. 1, the net force, F net , resulting from the pressure differential across the piston portion 34 supports the weight of the downhole tool 18 . The net force resulting from the pressure differential across the piston portion 34 can be expressed as:
F net =( P lc −P uc )·A lc (1)
[0018] where P lc is the pressure in the lower chamber 40 , P uc is the pressure in the upper chamber 38 or the wellbore pressure outside the cylinder 26 , A lc is the cross-sectional area of the lower chamber 40 .
[0019] The total force, F total , that is applied to the piston portion 34 by the downhole tool 18 can be expressed as:
F total =m tool ( g−a )+ F drag (2)
[0020] where m tool is the mass of the downhole tool 18 , g is the acceleration due to gravity, a is the acceleration of the downhole tool 18 , and F drag is the drag force acting on the downhole tool 18 . Drag force and acceleration are considered to be positive when acting in the same direction as gravity.
[0021] Assuming that the weight of the sensor section 24 and the weight of the connecting body 62 is negligibly small compared to the weight of the downhole tool 18 , then the net force, F net , resulting from the pressure differential across the piston portion 34 can be equated to the total force, F total , applied to the piston portion 34 by the downhole tool 18 , and the pressure, P lc , in the lower chamber 40 can then be expressed as:
P l c = 1 A l c [ m t o o l · ( g - a ) + F d r a g + P u c · A l c ] ( 3 )
[0022] From the expression above, it is clear that the pressure, P lc , in the lower chamber 40 changes as the downhole tool 18 is accelerated or decelerated. These pressure changes are transmitted to the pressure transducer 54 through the fluid in the lower chamber 40 and the pressure path. The pressure transducer 54 responds to the pressure changes in the lower chamber 40 and converts them to electrical signals. For a given acceleration or deceleration, the size of a pressure change or pulse can be increased by reducing the cross-sectional area, A lc , of the lower chamber 40 .
[0023] In operation, the downhole assembly 10 is lowered into the wellbore 12 with the lower chamber 40 and pressure path filled with a pressure-transmitting medium. When the downhole assembly 10 is accelerated in the upward direction, the total force, F total , which is applied to the piston portion 34 by the downhole tool 18 increases and results in a corresponding increase in the pressure, P lc , in the lower chamber 40 . When the downhole tool 18 is accelerated in the downward direction, the force, F total , which is applied to the piston portion 34 by the downhole tool 18 decreases and results in a corresponding decrease in the pressure, P lc , in the lower chamber 40 . The downhole assembly 10 may also be decelerated in either the upward or downward direction to effect similar pressure changes in the lower chamber 40 . The pressure changes in the lower chamber 40 are detected by the pressure transducer 54 as pressure pulses. Moving the downhole assembly 10 in prescribed patterns will produce pressure pulses which can be converted to electrical signals that can be interpreted by the electronics cartridge 20 in the downhole tool 18 as command signals.
[0024] If the downhole assembly 10 becomes stuck and jars are used to try and free the assembly, the pressure differential across the piston portion 34 can become very high. If the bottom-hole pressure, i.e., the wellbore pressure at the exterior of the downhole assembly 10 , is close to the pressure rating of the downhole assembly 10 , then the pressure transducer 54 can potentially be subjected to pressures that are well over its rated operating value. To prevent damage to the pressure transducer 54 , the fill plug 100 may be provided with a rupture disc 108 which bursts when the pressure in the lower chamber 40 is above the pressure rating of the pressure transducer 54 . When the rupture disc 108 bursts, fluid will drain out of the lower chamber 40 and the pressure path, through the fill port 96 , and out of the cylinder 26 . As the fluid drains out of the lower chamber 40 and the pressure path, the piston portion 34 will move to the lower end of the cylinder 26 until it reaches the end of travel, at which time the hydraulic strain sensor 16 becomes solid and the highest pressure the pressure transducer 54 will be subjected to is the bottom-hole pressure. Instead of using a rupture disc, a check valve or other pressure responsive member may also be arranged in the fill port 96 to allow fluid to drain out of the lower chamber 40 when necessary.
[0025] If the downhole assembly 10 becomes unstuck, commands can no longer be generated using acceleration or deceleration of the downhole assembly 10 . However, traditional methods such as manipulation of surface wellhead controls or movement of the downhole assembly 10 over fixed vertical distances in a column of liquid can still be used. When traditional methods are used, the pressure transducer 54 , which is now in communication with the wellbore, will detect changes in wellbore or bottom-hole pressure around the hydraulic strain sensor 16 and transmit signals that are representative of the pressure changes to the electronics cartridge 20 . It should be noted that while the downhole assembly 10 is stuck, pressure signals can still be sent to the downhole tool 18 by alternately pulling and releasing on the conveyance device 14 .
[0026] The invention is advantageous in that pressure signals can be generated by simply accelerating or decelerating the downhole tool. The pressure signals are generated at the downhole tool and received by the downhole tool in real-time. The invention can be used with traditional methods of pressure-signal transmission, i.e., manipulation of surface wellhead controls or movement of the downhole tool over fixed vertical distances in a column of liquid.
[0027] While the invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous variations therefrom
[0028] without departing from the spirit and scope of the invention.
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A hydraulic strain sensor for use with a downhole tool includes a housing having two chambers with a pressure differential between the two chambers. A mandrel is disposed in the housing. The mandrel is adapted to be coupled to the tool such that the weight of the tool is supported by the pressure differential between the two chambers. A pressure-responsive sensor in communication with the one of the chambers is provided to sense pressure changes in the chamber as the tool is accelerated or decelerated and to generate signals representative of the pressure changes.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application is a Divisional of U.S. Ser. No. 13/409,620 filed on Mar. 1, 2012, which is a Divisional of U.S. Ser. No. 11/557 filed on Nov. 6, 2006, which received U.S. Pat. No. 8,150,548, issued on Apr. 3, 2012, which claims priority to U.S. Provisional Patent Application No. 60/733,765 filed on Nov. 7, 2005.
BACKGROUND
1. Field
This invention relates to the field of process automation devices, and, in particular, to automation devices used in processes to be performed on chemical, biochemical, or biological samples and specimens.
2. Related Art
The use of automation in laboratory environments and pharmaceutical, manufacturing, and packaging or similar industries is well known. In molecular biology laboratories, for example, automation is used to transfer, mix, store, detect and analyze biological samples such as DNA, proteins, cells, tissues or similar samples in a high-throughput manner. In pharmaceutical industries automation is commonly used, for example, for high-throughput screening of compound libraries for discovering a new drug. Such processes usually involve one or more work samples that must go through different operations. Typically, such a system consists of a plurality of devices each of which performs one or more operations on a work sample. In laboratory environments, typically, standard labware or containers are used to hold a plurality of work samples, and a robot or a conveyer is employed to transfer the labware or containers from one device to another. The process, which consists of a set of work samples and operations is usually defined by a process manager, and may need to be re-defined from time to time. Therefore, the majority of such systems include a Computer Processing Unit (CPU) with a software package, which offers a Graphical User Interface (GUI) to the process manager for defining a new process and for running, monitoring, and controlling a process on the said plurality of devices.
While there are currently a number of such process automation systems in the market, there are several drawbacks to such systems. The currently available systems typically consist of a plurality of standalone and specialized instruments, such as for example a liquid handling robot, incubators and plate stackers that are integrated using a control computer and software that communicates with all such devices and synchronizes their operation. The drawback of integrating such specialized instruments is usually an increased complexity, higher cost, and lack of enough flexibility and scalability. Another drawback is that such independent instruments do not fully utilize the vertical dimension, which eventually leads to an increased footprint of the system. Also, the current systems typically use a multi-degree of freedom robot or a conveyer belt to transfer the samples. Such transfer mechanisms normally lack the precision required for high-precision operations such as microarraying. Therefore, the work sample has to first be transferred to a precise holder before any operations can be performed upon. Lack of specialized tools such as for example a very high-density pinhead is another shortcoming.
Accordingly, it would be advantageous to build a complex process automation system from mostly identical simpler building blocks that could be rearranged and installed in different configurations and could be equipped with a plurality of tools. It would also be advantageous to effectively utilize the vertical space in order to minimize the footprint. Further, it would be advantageous to utilize a high-precision transfer device or conveyer to transfer work samples and at the same time locate the samples for high-precision operations.
SUMMARY
One object of the invention is to provide a process automation apparatus in which the core of the system is made of mostly similar building blocks, called functional modules. This provides a modular, reconfigurable, and fully scalable approach to automation of processes that are typically found in laboratory environments, pharmaceutical industries, and high-precision manufacturing lines. Such modularity and scalability can be implemented in hardware and software of the apparatus.
Another object of the invention is to provide a process automation apparatus that minimizes the overall footprint by effectively using the available vertical space (Z direction).
Another object of the invention is to provide a process automation apparatus in which one or more functional modules are arranged along a precise conveyer device such that the conveyer constitutes the X-axis for the functional modules. Therefore, a functional module needs to move the tool in only two directions of Y and Z in order to achieve the full functionality of a 3D X, Y, and Z gantry robot.
Another object of the invention is to provide specialized tools and sub-modules for the said process automation apparatus. That includes a very high-density pinhead tool, a re-arrayer pinhead tool and a wash tower sub-module.
Another object of the invention is to provide a process automation apparatus in which a computer having user interface elements such as display, keyboard, mouse, and control software is operably connected to the said plurality devices and tools. The control software provides a graphical user interface (GUI) for the user to define new processes or edit the existing ones, and it supports the reconfigurability and scalability features of the hardware.
BRIEF DESCRIPTION OF DRAWINGS
The invention is described by way of example only, with reference to the accompanying drawings, in which:
FIG. 1 is a perspective view of an exemplary configuration of the modular and scalable apparatus for automating a process in accordance with an embodiment of the present invention;
FIG. 2 is an illustration corresponding to FIG. 1 , but showing a schematic top view of the exemplary configuration of the modular apparatus in accordance with an embodiment of the present invention;
FIG. 3 is a perspective view of an example functional module used in the modular apparatus in accordance with an embodiment of the present invention;
FIGS. 4A-4C correspond to FIG. 3 , but show the movement of the general purpose tool interface of the present invention in Y and Z directions, in accordance with an embodiment of the present invention;
FIGS. 5A and 5B correspond to FIGS. 4A and 4B respectively, but show a schematic top view of the functional module and the movement of the tool interface in Y direction, in accordance with an embodiment of the present invention;
FIG. 6 is a perspective view of the tool interface and an exemplary gripping tool attached to the horizontal interface plane in accordance with an embodiment of the present invention;
FIG. 7 is a perspective view of the tool interface and an exemplary pinhead tool attached to the horizontal interface plane in accordance with an embodiment of the present invention;
FIG. 8 is a schematic top view of a high-capacity labware stacking device comprising a functional module with a rotary base and a plurality of shelves, in accordance with an embodiment of the present invention;
FIG. 9 is a schematic top view of another exemplary configuration of the modular and scalable apparatus for automating a process in accordance with an embodiment of the present invention;
FIG. 10 is a schematic top view of another exemplary configuration of the modular and scalable apparatus for automating a process in accordance with an embodiment of the present invention;
FIG. 11 is a perspective view of a wash tower sub-module of the modular apparatus of an embodiment of the present invention;
FIG. 12 is a perspective view corresponding to FIG. 11 , but shows the assembly of side panels and a wash basin, in accordance with an embodiment of the present invention;
FIG. 13 is a perspective view corresponding to FIG. 11 , but shows another arrangement of the wash stations in which a wash basin is replaced with circular brush station, in accordance with an embodiment of the present invention;
FIG. 14 is a perspective view showing the components and assembly of a circular wash station, in accordance with an embodiment of the present invention;
FIG. 15 corresponds to FIG. 14 , but shows cross-sectional views of a circular wash station assembly, in accordance with an embodiment of the present invention;
FIG. 16 is a perspective view showing the components and assembly of a circular brush station, in accordance with an embodiment of the present invention;
FIG. 17 is a top view of an example replicating pinhead tool of the modular apparatus of an embodiment of the present invention;
FIG. 18 corresponds to FIG. 17 , but shows the first option for constructing the replicating pinhead tool, in accordance with an embodiment of the present invention;
FIG. 19A corresponds to FIG. 17 , but shows the top view of a 96-pin replicating tool, in accordance with an embodiment of the present invention;
FIG. 19B corresponds to FIG. 17 , but shows the top view of a 384-pin replicating tool, in accordance with an embodiment of the present invention;
FIG. 19C corresponds to FIG. 17 , but shows the top view of a 768-pin replicating tool, in accordance with an embodiment of the present invention;
FIG. 19D corresponds to FIG. 17 , but shows the top view of a 1536-pin replicating tool, in accordance with an embodiment of the present invention;
FIG. 20 illustrates a sample plate with 1536 different colonies of Yeast cells made by a 1536-pin replicating tool of FIG. 19D , in accordance with an embodiment of the present invention;
FIG. 21 corresponds to FIG. 17 , but shows the second option for constructing the replicating pinhead tool, in accordance with an embodiment of the present invention;
FIG. 22 is a perspective view of a 96-pin re-arraying pinhead tool of the modular apparatus of an embodiment of the present invention;
FIG. 23 corresponds to FIG. 22 , but shows the side view of a re-arraying tool with 96 separately indexable pins, in accordance with an embodiment of the present invention;
FIG. 24 corresponds to FIG. 22 , but shows the cross-section of one exemplary pin with its guiding and actuation mechanism, in accordance with an embodiment of the present invention;
FIG. 25 corresponds to FIG. 24 , but shows the cross-section of one exemplary pin with its actuation mechanism during the operation, in accordance with an embodiment of the present invention;
DETAILED DESCRIPTION
In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the invention. It will be apparent, however, to one skilled in the art that the invention can be practiced without these specific details.
Reference in this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Moreover, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but not other embodiments.
FIG. 1 illustrates an exemplary configuration 10 of a modular and scalable apparatus for process automation according to an embodiment of the present invention (hereinafter referred to as an automation system). The automation system 10 for example can be used for replicating or transferring an array of biological samples (e.g., Yeast cells) from one sample container to another one. It is to be understood that the automation systems disclosed herein are not limited to the configuration shown in FIG. 1 . This will become more evident in subsequent parts of this document where other exemplary configurations of such a system are disclosed.
FIG. 2 is an illustration corresponding to FIG. 1 , but showing a schematic top view of the automation system 10 , in accordance with an embodiment of the present invention. As illustrated in FIGS. 1 and 2 , one embodiment of the process automation system 10 of the present invention comprises a plurality of functional modules 20 , at least one conveyer 50 , a plurality of tools 42 and 80 , and sub-modules 60 and 70 . The conveyer comprises a tray 52 , which has one or more holders 54 for holding sample containers 98 . The containers 98 are precisely locked in position using actuators 55 and are transferred from one functional module 20 or station to another one by the conveyer 50 .
A functional module 20 comprises at least one general-purpose tool interface 26 and a device for moving the tool interface in space. In a preferred embodiment, a functional module 20 comprises a device 22 for moving in Z or vertical direction and a device 24 for moving in Y or horizontal direction towards the sub-modules 60 or 70 . A typical process involves one or more work samples that have to go through a series of operations. Work samples can be any liquid solution or solid components and in one embodiment comprise biological, biochemical or chemical samples such as Yeast, bacteria or other types of cells, DNA, RNA or protein solution samples that are carried in one or more sample containers or labware 98 . FIG. 20 shows an exemplary sample plate 98 that carries an array of 1536 different colonies of Yeast cells 96 . The cell colonies are grown on a proper growth media 97 .
A functional module 20 performs at least one operation on work samples or sample containers. The operation of a functional module 20 is normally determined by the type of tool(s) and sub-module(s) that are operably connected to it. Such a combination of a functional module 20 and a tool(s) and sub-module(s) that are operably connected to it is hereinafter referred to as a machine. For example, in FIG. 1 (from the right side) and FIG. 2 (from the left side), each of the first two functional modules 20 is equipped with a gripping tool 42 and a shelf sub-module 60 . The third functional module 20 in FIG. 1 is equipped with a replicating tool 80 and a wash-tower sub-module 70 . Therefore, there are three machines 11 , 12 , and 13 and one conveyer 50 in the exemplary automation system embodiment illustrated in FIG. 1 or 2 . The first two machines 11 and 12 are hereinafter referred to as plate stackers and the third machine is hereinafter referred to as a plate replicator.
A plate stacker machine 11 or 12 comprises a functional module 20 , a gripping tool 42 , and a shelf sub-module 60 . The shelf sub-module 60 comprises a plurality of shelves 62 . A shelf is used to store a sample container (hereinafter also called a “plate” or a “micro-titer plate”) 98 in a process. A gripping tool 42 is used by a functional module 20 to grip and transfer a plate from one location to another one, e.g., from a stacker shelf 62 to a conveyer holder 54 , from one stacker shelf 62 to another stacker shelf 62 , or from a conveyer holder 54 to a stacker shelf 62 . A gripping tool 42 is also used to remove the lid of a sample container 98 , to hold a lid or a container in space, or to put back the lid of a sample container 98 .
A plate replicator machine 13 comprises a functional module 20 , a replicating tool 80 , and a wash-tower sub-module 70 as illustrated in FIG. 1 in accordance with an embodiment of the present invention. The machine is used to replicate or transfer an array of work samples such as Yeast cells from one sample container 98 to another one. It is also used to re-format the samples, for example re-formatting four 96-format arrays into one 384-format array of samples. The replicating tool 80 will be described in more detail in subsequent parts of the document. The wash-tower 70 is used to clean and sterilize the replicating tool 80 after a replication and also to pre-condition or pre-wet the tool before a replication. A wash-tower 70 comprises several units (hereinafter also called “modules” or “devices”) 72 , 74 , 76 , 78 , and 79 , wherein a module performs a specific cleaning or pre-conditioning operation. Such units of the wash-tower 70 will be described in more detail in subsequent parts of the document.
The abovementioned tools and sub-modules are only two examples of a group of tools and sub-modules that can be connected to a functional module 20 in order to create new machines in accordance with embodiments of the present invention. As should be obvious to one of ordinary skill in the art, an automation system embodiment of the present invention may suitably comprise other tools that are commonly used to automate laboratory processes, including but not limited to different formats of pipettors or liquid handling tools, bar-code readers, CCD (Charge Coupled Device) cameras, colony-picking tools, a magnetic pinhead, and microarraying print-heads. Similarly, by way of example and not limitation, a sub-module as disclosed herein may comprise a stacker shelf, a carousel, a stacker shelf within an incubator, a carousel with incubator, an incubator, a wash tower, a shaker, a centrifuge, a vacuum filteration manifold, a plate reader, a slide scanner, a gel reader, a magnetic stierer, a pierecer, a thermocycler, a plate reader, or a reagent library.
It is an advantageous aspect of automation system embodiments of the present invention that adding a new operation or functionality to the system is just a matter of replacing a tool and/or a sub-module. Also, it is to be appreciated that the number of functional modules 20 is not limited to three, and any number of them can be used to automate simpler or more complicated processes. This allows for said modularity, scalability, and reconfigurability of such an automation system.
In other words, the building blocks of such an automation system are the functional modules 20 and conveyer(s) 50 . Functional modules are equipped with suitable tools and/or sub-modules to perfoim operations on work samples, and the conveyers are used to transfer the work samples among the functional modules. The functional modules and conveyers are operably connected to at least one controller (hereinafter also referred to as a central processing unit (CPU)) with a human-machine interface (HMI) using one or more communication links. In one embodiment, one or more RS-232, RS-420, RS-485, universal serial bus (USB), or Ethernet links are used in order to exchange signals and commands. The CPU can be a personal computer with 8086 types of processors or any other personal or mini-computer or mainframe. The CPU controls, synchronizes, and integrates the operation of the functional modules, conveyers, and their tools and sub-modules, and the HMI provides a Graphical User Interface (GUI) for a user to define and excecute (or run) a desired laboratory or similar process.
A functional module 20 comprises a general-purpose tool interface 26 that provides a unified way for attaching one or more different tools. A functional module further comprises one or more devices such as 22 and 24 that move the tool interface 26 in one or more desired directions in space. In one embodiment, a functional module moves the tool interface 26 in Z and Y directions, as illustrated in FIG. 4 . FIG. 3 shows an exemplary embodiment of a functional module 20 , in accordance with an embodiment of the present invention. The device 22 comprises a motor 27 and a linear actuator 21 that are used to move the tool interface 26 in vertical or Z direction. Similarly, the device 24 comprises a motor 23 and a linear actuator 25 that are used to move the tool interface 26 in horizontal direction Y. Such movements are illustrated in FIGS. 4 and 5 . It is to be appreciated that a functional module may comprise other types or directions of movements for more complicated operations. In one embodiment, a functional module also comprises an enclosure 41 that contains the required electrical, pneumatic and hydraulic components of the module, and a fixed base 94 that defines the location and orientation of the functional module in relation to the other devices in the automation system.
FIGS. 6 and 7 show the details of a general-purpose tool interface 26 , in accordance with an embodiment of the present invention. Two exemplary tools, i.e. a gripper 42 and a replicator 80 are shown to demonstrate the function of the general-purpose tool interface 26 . A general-purpose tool interface 26 comprises two interface planes: a vertical plane 28 and a horizontal plane 29 . The two interface planes have similar features, therefore only the interface plane 28 is described here. Having two interface planes instead of one is a unique feature that provides more flexibility in attaching tools to a functional module. Some tools, e.g. a gripper 42 or a replicator 80 , are more suitably attached to the horizontal interface plane 29 as shown in FIGS. 6 and 7 , and some tools, e.g. a vertical CCD camera, are more suitably attached to a vertical interface plane, in accordance with embodiment of the present invention. More complicated tools may use both interface planes.
As illustrated in FIG. 6 , an interface plane 28 comprises two accurate bushings 31 for precise mechanical registration of a tool with-respect-to the general-purpose tool interface 26 , a screw mechanism 35 and an access hole 34 for attaching or detaching a tool, a plurality of pneumatic or hydraulic ports 32 , and at least one electrical connector 30 , in accordance with an embodiment of the present invention. A tool has an attachment site 46 that is complementary to a tool interface plane 28 or 29 . This means that features on a tool interface plane 28 will suitably pair with corresponding features on a tool's attachment site 46 . For example, a tool comprises a threaded hole that matches the screw 35 of the general-purpose tool interface plane 26 , or pins that pair with the corresponding bushings 31 of the general-purpose tool interface 26 , and so on. Such an arrangement allows for the electrical and pneumatic or hydraulic connections required for the operation of a tool to be provided after the tool is attached to the interface device 26 .
For example, in FIG. 6 , the gripping tool 42 comprises an attachment site 46 , a pneumatic actuator 45 , two aims 43 with two jaws 44 , and a switch that detects when the gripper is full or empty, in accordance with an embodiment of the present invention. One or more pneumatic lines required for the operation of the actuator 45 , and electrical wires for the detection switch, are automatically connected when the tool 42 is attached to the general-purpose tool interface device 26 . This provides a high level of modularity in which a tool can be easily exchanged in a matter of seconds. The tool exchange can be done manually or can be automated. FIG. 7 shows how a replicating tool is attached to the tool interface device 26 , in accordance with an embodiment of the present invention. In this case, the replicating tool does not require any electrical, pneumatic, or hydraulic signals for its operation and only requires a mechanical attachment and a precise registration. FIG. 17 shows the top view of a replicating tool in which the attachment site 46 is illustrated as part of the base plate 141 , in accordance with an embodiment of the present invention. Two mechanical pins 151 will pair with the bushings 31 of the tool interface plane 29 to provide a precise alignment of the tool after attachment. The mechanical attachment is achieved using a screw 35 on the bottom face 29 of the tool interface 26 and a threaded hole 152 on the tool 80 . The access to the bottom screw 35 is obtained through an access hole 34 on top of the tool interface 26 shown in FIG. 7 .
A typical operation cycle of the automation system 10 in FIG. 1 can be best described by way of example, according to an embodiment of the present invention. For purposes of exemplary illustration, consider that the user wants to replicate twenty sample containers 98 like the one shown in FIG. 20 (hereinafter referred to as source plates) onto twenty blank sample containers (hereinafter referred to as destination plates). The steps are as follows:
1. The user loads the shelves 62 of the first stacker machine 11 with twenty source plates and the shelves 62 of the second stacker machine 12 with twenty destination plates starting from the bottom shelf. To load the shelves 62 , the user rotates the shelf sub-module 60 on the base 95 so that the shelves face the user side. This orientation is illustrated in FIG. 1 for the first stacker 11 . The sub-module 60 can also be removed from the base 95 , loaded outside, and put back on the base 95 . Each shelf 62 holds one source plate 98 . After loading all twenty plates, the user rotates the shelf sub-module 60 on the base 95 such that the shelves 62 face the functional module 20 (as illustrated in the second stacker machine 12 ). 2. The user runs a pre-defined procedure using the HMI of the CPU. A procedure defines the required steps for the system to complete a replication process. 3. Using the functional module 20 and the gripping tool 42 , machine 11 picks up one source plate, and machine 12 picks up one destination plate from their corresponding shelves 62 . 4. The conveyer 50 moves the tray 52 such that the right holder 54 stops in front of the functional module 20 of the first stacker 11 . The distance between the functional modules 20 of the machines 11 and 12 is made equal to the distance between the two holders 54 of the tray 52 . This allows that when the right holder 54 is in front of the functional module 20 of the first stacker 11 , the left holder is in front of the functional module 20 of the second stacker 12 . 5. The first stacker 11 puts the source plate on the right holder 54 , and simultaneously the second stacker 12 puts the destination plate on the left holder 54 . The plates 98 are locked in position using actuators 55 . 6. The first stacker 11 picks up the lid of the source plate, and holds the lid in a safe position above the conveyer. 7. The conveyer moves the tray towards the replicating machine 13 along the X-axis such that the source plate is positioned accurately in front of the replicating machine 13 (see FIG. 2 ). 8. Referring to FIG. 20 , the machine 13 picks up samples 96 from the container 98 using a replicating tool 80 . Referring to FIG. 7 , a replicating tool 80 comprises a plurality of pins 144 , where each pin is used to pick up and replicate one sample 96 from the container 98 . When a pin 144 dips into a cell colony 96 , a large number of cells stick to the tip of the pin. If this pin touches the surface of a new or blank container, part of the cells are transferred (or replicated) onto the new surface. The result generally appears as a small spot on the new surface. 9. The conveyer moves the tray back to the original position such that the source plate is positioned in front of the first stacker 11 . 10. The first stacker 11 puts back the lid of the source plate, and simultaneously, the second stacker 12 picks up the lid of the destination plate. 11. The conveyer moves the tray towards the replicating machine 13 along the X-axis such that the destination plate is positioned accurately in front of the replicating machine 13 (see FIG. 2 ). 12. The replicating machine 13 replicates the cells that stick to the pins 144 of the replicating tool 80 (see FIG. 7 ) onto the blank surface of the destination plate. 13. The conveyer moves the tray back to the original position such that the destination plate is positioned in front of the second stacker 12 . 14. The second stacker 12 puts back the lid of the destination plate. 15. The replicating machine 13 starts sterilizing the pins 144 of the replicating tool 80 in the wash-tower sub-module 70 . The sterilization process comprises several steps of washing followed by a drying step at the end in the dryer station 79 . Washing steps comprise moving the replicating tool 80 to different wash stations 72 , 76 , and 78 . 16. While the tool 80 is being washed, the stacker machines 11 and 12 pick up the first pair of source and destination plates 98 from the holders 54 (Note: the plates are unlocked by de-activating the actuators 55 before they can be picked up from the holders 54 ). 17. The first source and destination plates are put back on the shelves 62 and a new pair is removed from the shelves 62 and transferred to the conveyer holders 54 . 18. After the wash cycle is completed, the replicating process is started from the step 6 above. 19. Such a cycle is repeated until all 20 pairs of source and destination palates are processed.
It is to be appreciated that the above procedure is used only to illustrate an operation cycle by way of example, and it will not limit the user from automating any other processes by defining a new set of tasks. The user of the system can define any number of procedures using the provided Graphical User Interface (GUI) and store them for later use.
FIG. 11 shows a wash-tower sub-module 70 , according to an embodiment of the present invention. As illustrated in FIG. 11 , a wash-tower 70 comprises a plurality of devices that are arranged vertically and each device is used to perform an operation on the tool such as pre-conditioning, cleaning, or drying. It is to be appreciated that the wash-tower 70 in FIG. 11 is presented by way of example and the order, number, and type of devices in the wash-tower is not limited to the one shown in FIG. 11 . For example, FIG. 13 shows another configuration of a wash-tower 70 in which the wash basin 76 is replaced with a circular brush station 77 , in accordance with another embodiment of the present invention. A typical wash and sterilization operation involves several steps of cleaning in different solutions followed by a drying step. The number of cleaning steps and the type of solutions used in each step depend on the tool and work samples. For example, for a replicating tool 80 that uses an array of pins 144 (see FIG. 7 ) for transferring biological samples such as Yeast cells from one sample plate to another one, the following cleaning procedure can be used:
1. In a first step, the pins are dipped for about thirty seconds or more in the circular wash station 72 which is filled with distilled and de-ionized water. At this step, most contaminants such as Yeast cells tend to separate from the pins and float or subside at the bottom of the wash station. As will be illustrated later, the circular wash station is designed to completely drain, rinse and refill the wash station automatically after one wash or after every few washes. This helps reduce the likelihood of cross-contamination between the washes. Optionally, a wash station may be oval instead of circular. 2. In a second step, the pins are cleaned in an ultrasonic cleaner 78 , which is filled with water or diluted ethanol. The ultrasonic cleaner comprises a metal tank filled with a wash solution and an ultrasonic transducer that induces high-frequency waves inside the solution. The waves generate dynamic forces that separate contaminants from the pins. 3. After cleaning in the ultrasonic cleaner 78 , the pins are dipped in the wash basin 76 , which is filled with diluted ethanol or another disinfectant. 4. In a forth step, the pins are dipped in the second wash basin 76 , which is filled with 90% ethanol or similar solution. This step is generally the last step of sterilization and the first step of drying, as the 90% ethanol evaporates and dries quickly in air. 5. The dryer 79 then dries the pins by blowing warm air from the top.
After sterilization, the tool is ready for replicating another set of work samples. A pre-conditioning step might be needed in some cases. For example, it is observed that before replicating some biological samples such as Yeast cells, it would be advantageous to pre-wet the pins in distilled water. A pre-wetting station 74 is used for this purpose. This station comprises a container with a lid, and a lid-lifting mechanism. The lid is removed automatically for pre-wetting the tool, and after pre-wetting, it will be put back on the container to prevent contamination of the pre-wetting solution.
FIG. 12 shows an exemplary design of a wash-tower 70 with the main components and their assembly, in accordance with an embodiment of the present invention. The two side parts 105 constitute the main structure. The side covers 106 cover the longitudinal openings of the side parts 105 . Such openings are used to run liquid and gas tubes and electrical wires to the devices at different levels. By removing the side covers 106 one can access the electrical wires or tubes. In one embodiment, one side opening is used for running electrical wires and the other one is used for running tubes. Some devices, such as wash basin 76 and the ultrasonic cleaner 78 are mounted on shelves 107 such that they can slide out horizontally or completely removed (as shown in FIG. 12 for the wash basin 76 ) for manual draining, cleaning, or refilling after completing a process.
As it is shown in FIG. 12 , a wash basin 76 comprises a top frame 104 and a wash container 102 that can slide on shelves 107 using the side slots 103 . The top frame 104 prevents the liquid to splash out when the basin is filled and manually moved back to the original position shown in FIG. 11 .
FIG. 13 shows another configuration of a wash-tower sub-module 70 , in which the first wash basin 76 in FIG. 11 is replaced with a circular brush station 77 (see FIG. 16 for details) for efficient cleaning of sticky samples, in accordance with an embodiment of the present invention. In this configuration, after the first step of cleaning in the circular wash station 72 , the pins are cleaned in a circular brush station 77 filled with diluted ethanol or other sterilization solutions, followed by the ultrasonic cleaner 78 , wash basin 76 with 90% ethanol, and the dryer 79 .
An optional embodiment of the automation system, specialized for pre-conditioning, cleaning, or drying, comprises a wash-tower sub-module 70 and a functional module 20 , but no conveyer 50 . An advantage of such an embodiment is that it takes advantage of vertical space and minimizes the footprint of the specialized automation system.
FIG. 16 shows the components and assembly of a circular brush station 77 , in accordance with an embodiment of the present invention. The base plate 122 is used to mount the circular brush station 77 on the wash-tower 70 (see FIG. 13 ). In one embodiment, the base plate 122 is attached to the side parts 105 (see FIG. 12 ) using screws. As is shown in FIG. 16 , the circular brush station 77 comprises a rotating mechanism 125 , a container 127 , and a circular brush 128 and 129 . In one embodiment, a top cover 131 may be used to minimize splashing. The rotating mechanism 125 rotates around its central shaft using for example an electrical DC motor and a gear head (not shown in FIG. 16 ). The gear head reduces the rotation speed to few revolutions per second and amplifies the motor torque. The container 127 contains the wash solution and the circular brush 128 and 129 . The circular brush comprises brushes 129 (only a few brushes are shown in FIG. 16 ) that are permanently attached to a base 128 such that they become one component. The wash container 127 sits on the rotating mechanism 125 and rotates with the mechanism 125 using two pins 126 . The wash container 127 can be easily removed for manual draining, cleaning, and refilling of the container and the brush. In an embodiment of the present invention, a user lifts and removes the top cover 131 , followed by lifting and removing the circular container 127 with the brush 128 and 129 . Then, if needed, the user drains and cleans the container 127 and the brush 128 and 129 . The brush is placed back into the container, and the container 127 is filled with a proper wash solution. Then, the filled container 127 is put back on the rotating disc 125 , followed by putting back the top cover 131 on the container 127 . The top cover 131 is an optional element that freely sits on the top edge of the container 127 and is positioned between the two side parts 105 of the wash-tower 70 (see FIG. 12 ). The two side parts 105 prevent the top cover 131 from rotating with the container 127 . The main function of the top cover 131 is to prevent the liquid from splashing out during the operation.
During the operation of the device 77 , the rotating mechanism 125 , container 127 , and circular brush 128 and 129 rotate together as shown in FIG. 16 , in accordance with an embodiment of the present invention. While the brush 129 is rotating, the replicating tool 80 moves back and forth inside the rectangular window of the top cover in the direction shown in FIG. 16 . The cleaning action happens when the tips of the pins 144 of the tool 80 (see FIG. 7 ) are in touch with the rotating brush 129 . By moving the tool 80 back and forth, the pins, including the ones that are closer to the center of rotation, are cleaned properly and uniformly.
FIG. 14 shows the components and the assembly of a circular wash station 72 , in accordance with an embodiment of the present invention. It comprises a circular or oval container 112 , a top cover 113 , a centerpiece 116 , a drain valve 119 , and a metal ball 115 . The cross-section of the container is shown in FIG. 15 . The container 112 has one or more side holes or ports 114 . In one embodiment, two side holes 114 (approximately 180° apart) are used. Through each side hole 114 , one tube is inserted into the container 112 tangent to the inside wall. The inserted tube(s) is used to pump a cleaning solution into the container 112 . The liquid enters the container 112 near the top and tangent to the inside wall (see the cross section in FIG. 15 ). The liquid then follows a spiral path to the bottom of the container 112 towards the centerpiece 116 , creating a whirlpool. The liquid is drained through the side holes 117 and the exit port 118 of the centerpiece 116 , when the valve 119 is open. To improve the draining efficiency, vacuum is used to suck the liquid from the bottom of the valve 119 . The design of the centerpiece 116 and the existence of the metal ball 115 increase the efficiency of the suction. For example, if the centerpiece 116 and the metal ball 115 were not used and the liquid was drained directly through a centre hole, it would mostly drain air rather than liquid because the eye of the whirlpool would be located at that centre of the exit port. Therefore, instead of draining the liquid directly from the centre, the embodiment blocks the centre and uses the side holes 115 to drain the liquid. The metal ball 115 is used to break the symmetry of the whirlpool at the centre and improve the drain efficiency. Optionally, other obstacles, such as a dowel pin attached to the container near the centre, can be used instead of a ball for breaking the symmetry. But, the metal ball has the advantages of simplicity, cost, and performance. When the container 112 is being rinsed, the metal ball 115 slowly rolls inside the container and its own surface will get cleaned as well.
A typical operation cycle of a circular wash station 72 , in accordance with an embodiment of the present invention, is as follows:
1. Fill operation: To fill the container 112 , the drain valve 119 is closed, and the wash solution is pumped through the ports 114 , preferably with a slow speed in order to avoid creating a whirlpool. Optionally, another input port is used for filling the container. 2. When the wash station is used several times, the wash solution is generally contaminated and needs to be replaced. The container needs to be drained, rinsed, and refilled. 3. Drain operation: The drain valve 119 is opened, and the contaminated solution is drained through the bottom hole 118 into a waste bottle. For faster draining, vacuum is applied to the waste bottle. 4. Rinse operation: While the drain valve 119 is open and vacuum is applied to the waste bottle, wash solution is pumped into the container 112 through the input port(s) 114 with high speed. Simultaneously, the input water is drained from the bottom port 118 . The input water creates a whirlpool that cleans the internal surface of the container 112 , and the surfaces of the metal ball 115 and centerpiece 116 . 5. Refill operation: This operation is identical to the fill operation above.
FIG. 17 shows the top view of a replicating pinhead tool 80 (hereinafter also referred to as a “pinhead”), in accordance with an embodiment of the present invention. The tool 80 has an attachment site 46 , which has two pins 151 and a threaded hole 152 for attaching the tool to the general-purpose tool interface 26 (see FIG. 7 ). A replicating tool 80 comprises a plurality of pins 144 that are arranged in specific formats, for example in a standard rectangular-array format such as a 96-format, 384-format, 768-format, or 1536-format as shown in FIGS. 19A, 19B, 19C, and 19D respectively, in accordance with embodiments of the present invention.
Replicating tools with solid pins are not new. Other companies, such as V&P Scientific, have been manufacturing replicating pinheads. However, the existing tools comprise one or two solid metal plate(s) with an array of holes that are precisely drilled into the plate(s). The pins freely float inside the holes. The number of pins and their size varies based on the application. The most commonly used formats of such pinheads include: 96=12×8 pins with 9 mm pin-to-pin distance, 384=24×16 with 4.5 mm pin-to-pin distance, and 1536=48×32 pins with 2.25 mm pin-to-pin distance, as shown in FIGS. 19A, 19B, and 19D respectively. The drawbacks of such pinheads include high cost of production and problems with manufacturability, especially when high-accuracy and high-density pinheads are needed. For example, drilling a large number of very accurate holes in a metal plate can be expensive. Even if one hole is damaged during the machining, the whole plate will be useless. The pins have to slide freely inside the holes (see FIG. 18 ), but they should not wobble inside the holes. That means the manufacturing tolerances for the pins and holes must be very tight. To minimize wobbling, we may use a thicker plate. However, that makes drilling the holes even more difficult, and would increase the overall weight. Also, if the pins are very thin, for example 0.7 mm or less, drilling accurate holes of that size can be very costly or nearly impossible. Also, this design is limited in terms of the maximum number of pins that can be fit into the specified standard space (around 108 mm by 72 mm).
To overcome such difficulties and minimize the production cost, a new design is disclosed herein. FIG. 18 shows the design of standard-density (i.e., 96, 384, 768, and 1536 formats) pinheads according to embodiments of the present invention. The new design uses tubes or bushings 147 instead of machined holes. One tube 147 is used for each pin 144 . Such tubes are produced in different sizes of ID (inside diameter), OD (outside diameter) and variety of lengths and with tight tolerances on the ID or OD. Since such tubes are mass-produced, the cost of each tube is very low. A preferred material for the tubes 147 and pins 144 is stainless steel, but other materials are also possible. The length of the tube can be increased to minimize the wobbling without tightening the tolerance between the pin and the tube. Therefore, the tolerance between the pin 144 and the tube 147 can be loosened to help the pin slide more freely. In one embodiment, two plates 142 are used to maintain a uniform distance between the tubes. In FIG. 18 , the base plate 141 constitutes the base for other components. The base plate 141 is typically made of aluminum or other suitable materials and is machined to precise dimensions. The parts 142 are typically made of polymers such as polycarbonate, polystyrene, polypropylene, or similar types. Other materials, for example Delrine, Teflon, Brass, or Aluminum can also be used. The advantage of using polymers is that they can be easily fabricated in large quantities using injection molding. To assure that the two plates 142 will be precisely aligned and parallel with each other, for example four corner tubes 148 can be used. Since those four corner tubes 148 are tightly fit into the four corner holes of the base plate 141 , and because the base plate 141 is accurately machined, the four corner tubes 148 will be at proper distance and parallel to each other. A preferred method of assembly would be to make the two parts 142 out of polymers and to lightly press-fit the tubes 147 and 148 into the holes of the two plates 142 . In order to simplify the assembly process, the holes can be slightly tapered. As it is shown in FIG. 18 , each pin 144 has a head 146 that prevents it from falling down and a tip 145 that can be made thinner than or the same size as the middle part of the pin.
Using the pin and tube method has another important advantage over the traditional pin and drilled-hole method. As illustrated in FIG. 21 , tubes can be assembled side-by-side to produce a very high-density pinhead that would have been otherwise nearly impossible or very costly to make with other techniques. In one embodiment, a pusher plate 156 with two setscrews 157 can be used to hold the tubes in place. Other methods can also be used to hold the tubes together. For example one may use epoxy glue to maintain the tubes in place even after removing the fixture.
An important feature of an automation system according to embodiments of the present invention is the modularity, scalability, and reconfigurability. This means that the same modules described in the automation system 10 of FIG. 1 or 2 can be re-arranged in different configurations in order to make new machines or automation systems for new applications. FIGS. 8 to 10 show other exemplary configurations of the automation system, in accordance with embodiments of the present invention.
FIG. 8 shows a high-capacity plate stacker machine (hereinafter also referred to as a “hotel”) 100 comprising a functional module 20 with a rotary base 18 and a plurality of shelf sub-modules 60 , in accordance with an embodiment of the present invention. A gripping tool 42 is used to transfer a labware 98 between the shelves of sub-modules 60 and the tray of conveyer 50 . In order to access a specified shelf 60 , the functional module 20 rotates on the rotary base 18 such that the gripping tool 42 is oriented right in front of the specified shelf 60 . It can be seen that by adding a rotary base 18 to the functional module 20 and by increasing the number of sub-modules 60 , one can create a new stacker machine 100 with a significant increase in capacity as compared with the stacker machine 11 in FIG. 1 . Another option is to have the functional module fixed and rotate the shelf sub-module assembly, as illustrated in FIG. 9 , in accordance with an embodiment of the present invention. A hotel 100 may comprise an enclosure 101 that maintains a controlled environment for the plates with physical or chemical conditions such as temperature, pressure, or humidity that are different from those of the outside environment. One may also use a separate enclosure 104 for each individual shelf sub-module 60 in order to maintain a different environmental condition only for specific sub-module(s).
FIG. 9 is a diagram showing another exemplary configuration 110 of the automation system according to an embodiment of the present invention. The automation system 110 comprises two hotels 100 that provide a high capacity storage space for sample containers 98 , a plurality of functional modules 20 , a plurality of tools and sub-modules 60 , 64 , 65 , and 66 , and two conveyers 50 with a tray that comprise three plate holders 54 . The conveyers 50 are used to move sample plates 98 between the hotels 100 and different functional modules 20 . The applications of such a system are vast. By changing the tools and sub-modules, different functionalities can be added to the system. For example, by using a 96-format or 384-format pipetting head as a tool, the automation system 110 becomes a high-capacity and high-throughput liquid handling system. By using a replicating tool 80 (see FIG. 1 ) and a wash-tower sub-module 70 (see FIG. 1 ), the same system in FIG. 9 becomes a high-capacity cell replicating system. By using two replicating tools 80 and two wash-towers 70 in the same system 110 , the throughput can be doubled as compared with the system 10 in FIG. 1 . The reason is that when one replicating tool is being washed and sterilized, the second replicating machine can replicate another set of labware.
FIG. 10 is a diagram showing another exemplary configuration 120 of the automation system according to an embodiment of the present invention. An automation system like the one in FIG. 10 can be used to automate very complicated processes, while maintaining a relatively small footprint and a low cost. The cost of the automation system is significantly less than comparable systems, as the core part of the system is made of few relatively simple modules. It not only reduces the development cost and time significantly, but also reduces the production cost due to repetition and reuse of identical or similar components. For example, the machining cost of a component is significantly reduced if a large quantity of that component is produced in one setup. Other advantages are reduced documentation, easier maintenance, and simplified stocking of components. The modularity and scalability of the automation system according to embodiments of the present invention is evident for example from the sequence of configurations presented in FIGS. 2, 8, 9, and 10 . It is also evident that such a system can be configured with new tools and sub-modules in order to be used for a plurality of applications. It is to be appreciated that the above configurations related to the present invention are by way of example only. Many other variations on such configurations should be obvious to one or ordinary skill in the art and such obvious variations are within the scope of the present invention.
FIG. 22 shows the assembly and components of a Re-arraying tool with ninety-six separately indexable pins, in accordance with an embodiment of the present invention. The tool consists of an actuation mechanism 160 with eight pneumatic or electrical actuators 161 . The actuation mechanism 160 moves along the linear bearings (or rails) 162 by means of a motor 168 and a lead screw 165 , in order to access different columns of pins. In this exemplary configuration with ninety-six pins, the pins are arranged in a rectangular format with eight rows and twelve columns. When the actuation mechanism aligns with a specified column of pins, any of those eight pins can be actuated separately or simultaneously by the corresponding actuator(s) 161 . FIG. 23 shows one column of pins 144 and the actuators 161 from the side view, in accordance with an embodiment of the present invention. FIG. 22 shows the tool's attachment site 46 with two locating pins 151 , one electrical connector 164 , and eight pneumatic fittings 163 , in accordance with an embodiment of the present invention. The attachment site is used to connect the tool to the general purpose tool interface 29 (see FIG. 6 ) of a functional module. When the tool is attached to the tool interface, the electrical connector 164 and pneumatic fittings 163 of the tool will connect to the corresponding connector and fittings of the tool interface 29 of the functional module, which provides the electrical and pneumatic power required for actuating the motor 168 and actuators 161 of the tool. This provides a high degree of modularity and functionality, as the re-arraying tool can be easily detached from a functional module and replaced by another tool, e.g., a replicating pinhead tool 80 , and therefore the same functional module can be used for multiple applications.
FIG. 24 illustrates the guiding and actuation mechanisms for each pin 144 , in accordance with an embodiment of the present invention. The pin 144 can float freely and precisely inside a bushing 170 . The bushing 170 also slides up/down in a precise hole 178 on the base plate of the tool. When the actuator 161 is not activated (left figure), the pin and its bushing are moved up by means of a spring 172 . The Cover plate 166 limits the upward movement of the bushing 170 . When the actuator 161 is activated (right figure), it pushes the bushing 170 and the inside pin 144 down against the spring 172 . FIG. 25 illustrates the operating sequence of a pin. When the actuator 161 is not activated ( FIG. 25 a ), the bushing 170 and the pin 144 are held up by means of a spring 172 . This represents the normal state of the ninety-six pins. When one pin has to move down to pick up or transfer a sample, the corresponding actuator 161 is activated ( FIG. 25 b ) and moves the bushing 170 and the pin 144 all the way down. If the pin 144 touches a solid work-surface 176 ( FIG. 25 c ), it will float up inside the bushing 170 and does not damage the sample or the work-surface. This is a unique and important feature of the re-arrayer device as disclosed herein. Furthermore, and as should be obvious to one of ordinary skill in the art, such floating pins can be used in a re-arrayer that does not comprise a moving actuation mechanism 160 , for example in a re-arrayer that comprises a conventional actuation mechanism.
The re-arraying tool in FIG. 22 can be used for picking randomly distributed samples on a work-surface and transferring them in a standard 96-format rectangular array. In applications related to biology research, the samples are typically biological samples such as bacteria colonies or Yeast cell colonies that are grown on a growth media, e.g., an agar surface.
While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative and not restrictive of the broad invention and that this invention is not limited to the specific constructions and arrangements shown and described, since various other modifications may occur to those ordinarily skilled in the art upon studying this disclosure. In an area of technology such as this, where growth is fast and further advancements are not easily foreseen, the disclosed embodiments may be readily modifiable in arrangement and detail as facilitated by enabling technological advancements without departing from the principals of the present disclosure or the scope of the accompanying claims.
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An apparatus and method for transferring plurality of samples from one sample container to another one is disclosed wherein each sample is randomly accessible and can be “cherry picked”. The disclosed method of actuation allows for using a smaller number of actuators than the number of sample transferring channels or pins and thereby simplifies the design and control of the sample transferring apparatus.
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TECHNICAL FIELD OF THE INVENTION
This invention relates to the addition of alloying elements to aluminum alloys. More particularly, it relates to methods of adding alloying elements to molten aluminum to maintain high levels in solid solution.
BACKGROUND OF THE INVENTION
In the aluminum industry, dispersoid-forming elements such as Zr, Mn, Cr, V, Ti, Sc and Hf are used to increase recrystallization temperature and to control the grain structure in cast and wrought products. Many different methods have been employed to add these types of alloying elements to molten metals. Typically, master alloys which contain the desired elements are added directly to the melt in the forms of a cast lump, bar, waffle or added as briquettes composed of mixtures of aluminum and elemental powders or chips.
The alloying elements in the master alloys are normally present in a form of coarse intermetallics such as for example Al 3 Zr. These intermetallics require superheat and a long period of holding time to be dissolved in the melt. The heavy intermetallics also tend to settle to the bottom of the holding furnace due to gravity. Thus, master alloys are generally added in the melting or holding furnace to allow sufficient time for the intermetallics to dissolve in the superheated melt which is occasionally stirred.
In addition, the level of these desirable dispersoid-forming elements in the commercial aluminum alloys has been limited to the liquid solubility at peritectic reaction temperature. For example, in the case of aluminum binary systems, the maximum liquid solubility of Zr, Cr, V and Hf is 0.12, 0.37, 0.2 and 0.2 wt. %, respectively. In commercial aluminum alloys, these maximum limits of liquid solubility at peritectic temperatures will be reduced even further. Casting of aluminum alloys containing dispersoid elements at levels above their natural saturation limit can result in formation of undesirable coarse primary intermetallics in the molten metal.
If coarse intermetallics are not filtered out of the molten metal, they will adversely affect the ability to cast the metal as well as the mechanical properties of the end product by reducing ductility, fracture toughness, or fatigue properties. Since coarse primary intermetallics can rapidly nucleate and grow in melts which exceed the maximum solubility limit, the conventional alloying approach is to add dispersoid-forming elements in the melting or holding furnace in amounts below the liquid saturation limit.
It would be highly desirable to form metal which has been cast such that it contains dispersoid-forming elements at a level greater than the liquid solubility limit of the elements. Supersaturated levels of dispersoid-forming elements in solid solution will increase the number of nucleation sites which form fine dispersoids during preheating of the cast alloy, which enables the recrystallization temperature to be increased, and inhibits grain growth during hot working.
For structural applications, a fine grain unrecrystallized microstructure has a better combination of strength, elongation and toughness than a coarse grain recrystallized alloy. Metallurgically, a high volume fraction of fine dispersoids which are less than about 0.1 microns in size are useful for retaining a fine grain unrecrystallized microstructure.
Currently the volume fraction of dispersoids which can be formed is limited by the liquid solubility of the dispersoid-forming elements in the alloy.
It is against this background that the present invention was made.
Accordingly, it is a principal object of this invention to provide aluminum alloys having high levels of fine dispersoids.
It is a further object of the present invention to provide a method for increasing the amount of dispersoid-forming elements in solid solution which is not limited to the liquid solubility level.
Another object of the invention is to provide a method to increase the volume fraction of dispersoids formed by precipitating from a supersaturated solid solution.
Yet another object of the present invention is to provide a method for casting aluminum alloys with supersaturated levels of dispersoid-forming elements.
Yet it is another object of this invention to provide aluminum alloys having levels of Zr greater than about 0.12 wt. %.
Yet it is another object of this invention to provide aluminum alloys having levels of Mn greater than about 2.06 wt. %.
Yet it is another object of this invention to provide aluminum alloys having levels of Cr greater than about 0.37 wt. %.
Yet it is another object of this invention to provide aluminum alloys having levels of V greater than about 0.2 wt. %.
Yet it is another object of this invention to provide aluminum alloys having levels of Ti greater than about 0.14 wt. %.
Yet it is another object of this invention to provide aluminum alloys having levels of Hf greater than about 0.20 wt. %.
Yet it is another object of this invention to provide aluminum alloys having levels of Y greater than about 0.16 wt. %.
Yet it is another object of this invention to provide aluminum alloys having levels of Nb greater than about 0.016 wt. %.
Yet it is another object of this invention to provide aluminum alloys having levels of Sc greater than about 0.47 wt. %
It is a further object of this invention to provide a method for casting aluminum alloys having levels of dispersoid-forming elements in solid solution greater than the liquid solubility limits.
These and other objects and advantages of the present invention will be more fully understood and appreciated with reference to the following description.
SUMMARY OF THE INVENTION
In accordance with these objects, there is provided a process of achieving a high level of dispersoid-forming elements in solidified aluminum alloys by the addition of a supersaturated master alloy to a molten aluminum alloy which is immediately solidified. The process comprises (a) forming a supersaturated master alloy containing dispersoid-forming elements in solid solution by rapidly solidifying a master alloy containing at least one dispersoid-forming element; (b) providing a body of molten aluminum alloy; (c) adding said rapidly solidified master alloy to the molten aluminum alloy at a rate sufficient to raise the wt. % of at least one dispersoid-forming element above its liquid saturation limit; and then (d) solidifying the molten aluminum alloy to form a solidified aluminum alloy possessing dispersoid-forming elements in solid solution above the liquid saturation limit.
A second aspect of the invention is a cast metal product in which the level of dispersoid-forming elements in solid solution is greater than the liquid saturation limit of the elements. In a preferred embodiment, metal product is an aluminum alloy and the dispersoid-forming elements are zirconium (Zr), manganese (Mn), chromium (Cr), vanadium (V), titanium (Ti), scandium (Sc), niobium (Nb), yttrium (Y) and hafnium (Hf).
BRIEF DESCRIPTION OF THE DRAWINGS
Other features of the present invention will be further described in the following related description of the preferred embodiment which is to be considered together with the accompanying drawings wherein like figures refer to like parts and further wherein:
FIG. 1 is a view of the flow of metal from a furnace to the casting pit.
FIG. 2 is an enlarged view of the casting facility of FIG. 1.
DEFINITIONS
The term "master alloy" is used herein to mean an aluminum base alloy in remelt ingot form containing at least 50% aluminum and one or more added elements for use in making alloying additions. The term master alloy is also used interchangeably in the art with the terms "rich alloy" and "hardener".
The term "dispersoid-forming elements" is used herein to mean alloy elements that precipitate from solid solution to form intermetallic dispersoids in a base alloy. Examples of dispersoid-forming metals for aluminum alloys include, but are not limited to, manganese (Mn), zirconium (Zr), chromium (Cr), vanadium (V), titanium (Ti), scandium (Sc), hafnium (Hf), yttrium (Y) niobium (Nb) and combinations thereof.
The term "rapidly solidified" is used herein to mean cooled from a liquid state into a solid state at rate of greater than about 100° C. per second or preferably greater than about 1000° C. per second. Rapidly solidified materials are preferably formed in the shape of thin ribbon, powder and flakes.
The term "coarse" as it refers to intermetallic particles formed from liquid solution is a particle being greater than about 5 microns.
The term "fine" as it refers to intermetallic dispersoid particles which are precipitated from solid solution is a particle being less than about 0.1 microns.
The term "continuous" as used herein refers to the progressive and uninterrupted formation of a cast metal ingot in a mold which is open at both ends. The pouring operation may continue indefinitely if the casting is cut into sections of suitable length at a location away from the mold. Alternatively, the pouring operation may be started and stopped in the manufacture of each casting. The latter process is commonly referred to as semi-continuous casting and is intended to be comprehended by the term "continuous".
DETAILED DESCRIPTION OF THE INVENTION
Referring first to FIG. 1, there is illustrated a typical flow path for molten metal 10 from a furnace 12 to the casting mold 24 used for continuously casting ingots.
Typically, molten metal 10 is held at superheated temperatures in furnace 12. Alloying elements are typically added to furnace 12. Some of the alloying elements are added to the melt using master alloys that have high concentrations of alloying elements, that is, 10-15%. These alloying elements are normally present in a form of coarse intermetallics. These intermetallics require a long holding time in furnace 12 to be dissolved in the melt. The melt must also be stirred since the heavy intermetallics tend to settle to the bottom of the holding furnace due to gravity.
Typically, metal 10 is held in furnace 12 for several hours. During this time, coarse intermetallics are dissolved in the melt to form a liquid solution. Molten metal leaves furnace 12 via trough 14 and enters fluxing unit 16 to remove hydrogen, calcium and sodium by gas fluxing.
Flux unit 16 has impeller 17 for dispensing a flux gas. Impeller 17 is mounted on shaft 18. Impeller 17 is rotated, and simultaneously with the rotating, a fluxing gas is added to the molten aluminum adjacent the dispenser. Flux units are well known in the art.
After the molten metal travels beneath baffle 19, it then passes through a filter 20 under baffle 21 as it flows via trough 22 to casting mold 24 to form, in this case, ingot 26.
Mold 24 is a conventional direct chill casting apparatus and may be internally cooled, usually with a liquid coolant 27 such as water. Mold 24 is typically constructed of a material having high thermal conductivity, such as aluminum or copper, to insure that the coolant temperature is transferred as efficiently as possible through the inner mold wall to the metal to effect solidification.
Ingot 26 has a lower solidified section 28, a mushy region 30 and a molten pool 32 of aluminum above. Molten metal pool 32 is supported by mold 24 incorporating cooling liquid 27. Molten aluminum 12 is flowed to molten pool 32, and solidified ingot section 28 is removed from mold 24 at a controlled rate by the lowering of a bottom block (not shown).
For certain alloying elements, such as dispersoid-forming elements, it is desirable to add such elements to the melt in a manner to form a liquid solution. Heretofore, this has been accomplished by:
1. adding the master alloys containing dispersoid-forming elements to superheated molten metal in melting furnace 12 where they have time to dissolve and be held in solution, and
2. limiting the concentration of the dispersoid-forming elements being added to molten metal 10 to levels below their natural saturation limit to avoid the formation of coarse intermetallics.
If dispersoid-forming elements are added to the melting furnace above their saturation limit in accordance with conventional alloying practices, they can form coarse primary aluminide intermetallic particles in the liquid which become trapped in the solidified metal. These coarse intermetallics could adversely affect the mechanical properties of the wrought product. Therefore, care has always been taken to limit the total concentration of the dispersoid-forming elements to avoid any negative impact on the resulting properties of the wrought product.
Surprisingly, Applicants have found that dispersoid-forming elements can be added to the molten metal at levels above the natural solubility limit for the alloy without forming coarse primary aluminide intermetallic particles.
Unexpectedly, Applicants have discovered that if dispersoid-forming elements are added directly to molten pool 32 at levels which form melts having supersaturated levels of dispersoid-forming elements, the resulting solidified metal does not contain coarse intermetallic particles which adversely affect the mechanical properties of the solidified metal.
FIG. 2 shows a rapidly solidified ribbon 40 of the material containing a dispersoid-forming element being added directly into molten metal pool 32 of ingot 26. Ribbon 40 is fed from spool 42 into a fixture 44 for directing the ribbon into the molten pool. The residence time between melting of ribbon 40 and solidification of the supersaturated alloy contained in molten metal pool 32 is sufficiently short as to permit dissolution of the master alloy ribbon containing at least one dispersoid-forming element in solid solution and subsequent freezing of the molten metal at the bottom of the crater without growing into larger particles, thereby maintaining high levels of dispersoid-forming elements in solid solution in the solidified ingot.
Due to natural convection in the molten metal pool 32, the supersatured liquid solution which is produced by the dispersoid-forming element is distributed uniformly in the pool of molten aluminum. The residence time of the dispersoid-forming element in the crater is short since the metal is immediately solidified into ingot. If it is desired to add the dispersoid-forming element zirconium, the ribbon may be comprised of 2.0 wt. % Zr or higher, the remainder aluminum. The feed rate of the ribbon can be controlled to provide the desired amount of Zr in the ingot. Further, when the ribbon is formed from a melt of aluminum and zirconium, it may be cast onto a roll or drum where fast solidification occurs to freeze Zr in the aluminum ribbon as a solid solution. Methods for making the rapidly solidified ribbon are known to the art.
To achieve a concentration of dispersoid-forming element above the liquid saturation limit, two factors must be kept in mind.
1. First, the dispersoid-forming element(s) is added to the liquid metal in a form in which the dispersoid-forming element is in solid solution.
2. Second, the dispersoid-forming element(s) is added at a location close to the crater of the ingot such that the melt is quickly solidified to reduce residence time of the supersatured liquid in the crater of the ingot. Since the dispersoid-forming element(s) is added at a concentration above the natural saturation point, a long residence time will result in the formation of coarse particles in the molten metal.
The benefit of the present invention is illustrated in the following example.
EXAMPLE
Melt spun ribbon having a composition of Al-6% Zr was formed using standard rapid solidification techniques. The ribbon was 0.009 inch thick and 1 inch wide. The ribbon was continuously fed into a pool of molten alloy 7150 at the casting head of a DC ingot. The ribbon was added to the melt at rate of 1000 inches per minute.
The 7150 alloy from the furnace had a Zr level of just below its natural solubility limit of 0.12% to avoid formation of coarse Zr intermetallics in the ingot. The continuous addition of the ribbon to the molten melt in the pool enables the Zr concentration to be increased above the solubility limit. After casting, the ingot was analyzed and the level of Zr in the cast ingot was measured to be at 0.21%.
Surprisingly, there were no coarse intermetallic particles in the ingot, indicating that Zr is saturated in the solid solution. This was unexpected since in prior art casting techniques, coarse intermetallics of zirconium aluminide form when the level of zirconium is above the natural saturation limit.
Unexpectedly, the as-cast grain size of the ingot was found to be approximately 5 times smaller than the grain size of AA7150 ingot containing Zr levels approaching its natural solubility limit of 0.12%.
It is to be appreciated that certain features of the present invention may be changed without departing from the present invention. Thus, for example, it is to be appreciated that although the invention has been described in terms of added Zr to aluminum at levels of 0.21%, it is not intended to be so limited. Greater amounts of the Zr could be added if higher feed rates, larger ribbons, or multiple ribbons were used to add Zr to the molten metal.
Whereas the preferred embodiments of the present invention have been described above in terms of being especially valuable in formation of supersatured levels of Zr in aluminum, it will be apparent to those skilled in the art that the same technique can be use for other elements. Thus for example, the same technique can be used to create supersatured levels of manganese, chromium, vanadium, titanium, scandium, hafnium, yttrium, niobium, and combinations thereof.
Whereas the preferred embodiments of the present invention have been described above in terms of the supersatured levels of zirconium in aluminum, it will be apparent to those skilled in the art that the present invention will be useful for other metals. Metals suitable for use with the present invention are not limited to aluminum and aluminum alloys. Objects formed from other metals such as magnesium, copper, iron, zinc, nickel, cobalt, titanium, and alloys thereof may also benefit from the present invention.
Whereas the preferred embodiments of the present invention have been described above in terms of continuous casting of aluminum, it will be apparent to those skilled in the art that the present invention will be useful in other casting methods. The terms "metal casting" and "solidifying" are intended to include metal casting techniques used in any of the commercial solidification processes, including continuous casting semi-continuously casting by the direct chill method, as well as strip or slab cast continuously by belts, block or roll casters. In addition, the invention may be used in other solidification processes such as spray forming, spray casting, atomization, rapid solidification, and splating.
Whereas the preferred embodiments of the present invention have been described above in terms of being especially valuable in producing aluminum alloy 7150, it will be apparent to those skilled in the art that the present invention will also be valuable in producing products made of other aluminum alloys containing about 75% or more by weight of aluminum and one or more alloying elements. Among such suitable alloying elements is at least one element selected from the group of essentially character-forming alloying elements consisting of manganese, zinc, lithium, copper, silicon, and magnesium. These alloying elements are essentially character forming for the reason that the contemplated alloys containing one or more of them essentially derive their characteristic properties from such elements. Usually, the amounts of each of the elements which impart such characteristics are, as to each of magnesium and copper, about 0.5 to about 10 wt. % of the total alloy if the element is present as an alloying element in the alloy; as to the element zinc, about 0.05 to about 12.0% of the total alloy if such element is present as an alloying element; as to the element lithium, about 0.2 to about 3.0% of the total alloy if such element is present as an alloying element; and as to the element manganese, if it is present as an alloying element, usually about 0.15 to about 2.0% of the total alloy.
The elements iron and silicon, while perhaps not entirely or always accurately classifiable as essentially character-forming alloy elements, are often present in aluminum alloys in appreciable quantities and can have a marked effect upon the derived characteristic properties of certain alloys containing the same. Iron, for example, which if present and generally considered as an undesired impurity, is sometimes desirably adjusted in amounts of about 0.3 to 2.0 wt. % of the total alloy to perform specific functions in certain alloys. Silicon may also be so considered, and while found in a range varying from about 0.05 to as much as 20% in casting alloys, is desirably added in the range of about 0.3 to 1.5% to perform specific functions in certain alloys. In light of the foregoing dual nature of these elements and for convenience of definition, the elements iron and silicon may, at least when desirably present in character-affecting amounts in certain alloys, be properly also considered as character-forming alloying ingredients.
The aluminum alloys included most preferably the wrought and forged aluminum alloys such as those registered with the Aluminum Association by the designations 2011, 2014, 2017, 2117, 2218, 2616, 2219, 2419, 2519, 2024, 2124, 2224, 2025, 2036, 4032, 5052, 5056, 5083, 5086, 5154, 5252, 5356, 5456, 5556, 5562, 56546101, 6201, 6009, 6010, 6111, 6013, 6151, 6351, 6951, 6053, 6060, 6022, 6061, 6262, 6063, 6066, 6070, 7001, 7005, 7010, 7016, 7021, 7029, 7049, 7050, 7150, 7055, 7075, 7175, 7475, 7076, 7178, 8090 and other appropriate alloys of similar designation. Of particular interest are the aluminum alloys 2014, 2024, 6061, 7050, 7150, 7055 and 7075. These aluminum alloys generally include the generic designation 2000 series alloys, 5000 series alloys, 6000 series alloys, 7000 series alloys, and 8000 series alloys.
It is also to be appreciated that although the invention has been described in terms of cast alloy, the method and apparatus of the present invention may also be employed with casting metal matrix composites, semi-solid alloys, metal laminates, and cermets.
Whereas the preferred embodiments of the present invention have been described above in terms of adding the master alloy containing dispersoid-forming elements directly into the crater of an aluminum ingot as it is being cast, it will be apparent to those skilled in the art that the master alloy containing dispersoid-forming elements can be added in or near the solidification zone in other casting methods.
It is also to be appreciated that although the invention has been described in terms alloying directly into the pool of molten metal in the head of an ingot as it is being cast, the present invention is not intended to be so limited. Those skilled in the art will recognize that the location of adding alloying additions of dispersoid-forming elements is not critical to practicing the invention. For example, dispersoid-forming elements may also be alloyed into the molten metal in the trough adjacent the ingot that is being cast. The key is to alloy the dispersoid-forming element above the liquid saturation limit at a point in the process where there is insufficient time for the dispersoid-forming element to form large particles in the solidified metal.
In addition, although the invention has been described in terms of alloying a single dispersoid-forming element at supersatured levels, it will be apparent to those skilled in the art that the same technique can be use for creating a product with multiple dispersoid-forming elements at supersatured levels. Thus for example, the same technique can be used to create supersatured levels of any combination of manganese, chromium, vanadium, titanium, scandium, hafnium, yttrium, niobium, and zirconium.
Although the invention has been described in terms of casting ingot, the invention is not intended to be so limited and applies to all forms of casting. The invention is intended to be equally applicable to products such as sheet, plate, wire, rod, bar, forging or extrusions. It is contemplated that the invention will be especially useful for tubular sporting goods products such as ball bats, lacrosse sticks, hockey sticks, polo sticks, field hockey sticks, ice hockey sticks, pool cues, arrows, gun scopes, wind surfing frames, sail board booms, inline skate components, wheelchairs, golf club shafts, bicycle frames and components such as handlebars, seat posts and suspension systems, ski poles, javelins, bowling pins and the like.
Further examples of applications of the improved products are vehicular panels. Vehicular panels are described in U.S. Pat. No. 4,082,578, incorporated herein by reference, and include floor panels, side panels, or other panels for cars, trucks, trailers, railroad vehicles and canoe or boat panels, aerospace panels and other shaped sheet and extrusion members, forgings and other members such as, for example, drive shafts.
Other examples of applications of the improved products are structural members including shipping pallets and containers made by shaping sheet, forging or extrusion members and riveting or welding the assemblies together. The improved aluminum extrusion, pipe and tube stock made in accordance with the present invention will be especially useful in automotive and aerospace applications. The aerospace applications include airplane wing and fuselage structural members such as, for example, stringer extrusions.
Many other applications of the improved products present themselves in view of the herein set forth advantages of the invention.
What is believed to be the best mode of the invention has been described above. However, it will be apparent to those skilled in the art that these and other changes of the type described could be made to the present invention without departing from the spirit of the invention. The scope of the present invention is indicated by the broad general meaning of the terms in which the claims are expressed.
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An aluminum alloy containing dispersoid-forming elements selected from the group consisting of Zr, Mn, Cr, V, Hf, Ti, Nb, Y, Sc and combinations thereof. The improved alloy comprises the dispersoid-forming elements partially in solid solution above the saturation limit and partialy in a form of aluminide particles having an average particle size of less than 1 micron.
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CROSS REFERENCE TO RELATED PATENTS (PATENT APPLICATIONS)
[0001] Reference should be made to the following commonly assigned prior patents (copending patent applications), and the contents of these patents (patent applications) are hereby incorporated in this application by reference.
Our Ref: Patent (Application) Number Issue (Application) Date F650 6,193,296 Feb. 27, 2001 F651 6,1865,74 Feb. 13, 2001 F655 6,2030,98 Mar. 20, 2001 F685 6,2541,64 Jul. 3, 2001 F686 09/608,669 Jun. 30, 2000 F687 09/648,190 Aug. 23, 2000 F716 09/729,973 Dec. 6, 2000 F781 10/005,739 Nov. 6, 2001 F817 unknown F818 unknown F819 unknown
TECHNICAL FIELD
[0002] The present invention relates to a vehicle occupant protection system for improving the crash safety of the vehicle.
BACKGROUND OF THE INVENTION
[0003] In recent years, motor vehicles have been often fitted with a pretensioner device which positively increases the tension of the seat belt for restraining the vehicle occupant at the time of a crash and improves the protection of the vehicle occupant. The deceleration acting on the vehicle occupant who is restrained to the seat by a restraint device such as a seat belt starts rising only when the forward inertia force acting on the vehicle occupant at the time of the crash has started to be supported by the seat belt. As it is not possible to eliminate a certain amount of resiliency and slack in the seat belt, the deceleration of the vehicle occupant reaches a peak level only when the vehicle occupant has moved forward a certain distance under the inertia force and the elongation of the seat belt has reached its maximum extent. The peak value of the deceleration of the vehicle occupant gets greater as the forward displacement of the vehicle occupant under the inertia force increases, and is known to be substantially larger than the average deceleration of the passenger compartment of the vehicle body.
[0004] When the relationship between the vehicle body deceleration and the vehicle occupant deceleration is compared to the relationship between the input and output of a system consisting of a spring (vehicle occupant restraint device) and a mass (mass of the vehicle occupant), it can be readily understood that the maximum elongation and time history of the spring are dictated by the waveform (time history) of the vehicle body deceleration. Therefore, it can be concluded that the waveform of the vehicle body deceleration should be controlled in such a manner that not only the average deceleration acting on the vehicle body is reduced but also the overshoot of the vehicle occupant deceleration due to the elongation of the spring (vehicle occupant restraint device) is minimized.
[0005] In the conventional vehicle body structure, the impact energy is absorbed by a crushable zone, consisting of an impact reaction generating member such as side beams and gaps defined between various components, provided in a front part of the vehicle body, and the waveform of the vehicle body deceleration is adjusted by changing the resulting reaction properties by means of the selection of the dimensions and deformation properties of such parts. The deformation mode of the vehicle body other than the passenger compartment at the time of a crash may also be appropriately selected so that the deceleration of the passenger compartment of the vehicle body may be reduced, and the deformation may be prevented from reaching the passenger compartment. Such vehicle body structures are proposed in Japanese patent laid open publication (kokai) No. 07-101354.
[0006] It is important to note that the injury to the vehicle occupant at the time of a vehicle crash can be minimized by reducing the maximum value of the acceleration (deceleration) acting on the vehicle occupant which is dictated by the waveform (time history) of the vehicle body deceleration. It is also important to note that the total amount of deceleration (time integration of deceleration) which the vehicle occupant experiences during a vehicle crash is fixed for the given intensity of crash (or vehicle speed immediately before the crash). Therefore, as shown in FIG. 6 for instance, the ideal waveform (time history) of the vehicle body (seat) deceleration (G 2 ) for the minimization of the vehicle occupant deceleration (G 1 ) should consist of an initial interval (a) for producing a large deceleration upon detection of a crash, an intermediate interval (b) for producing an opposite deceleration, and a final interval (c) for producing an average deceleration.
[0007] The initial interval allows the vehicle occupant to experience the deceleration from an early stage so that the deceleration may be spread over an extended period of time, and the peak value of the deceleration to be reduced. According to a normal vehicle body structure, owing to the presence of a crushable zone in a front part of the vehicle and a slack and elongation of the restraint system such as a seat belt, it takes a certain amount of time for the impact of a crash to reach the vehicle occupant. The delay in the transmission of deceleration to the vehicle occupant must be made up for by a subsequent sharp rise in deceleration according to the conventional arrangement. The final interval corresponds to a state called a ride-down state in which the vehicle occupant moves with the vehicle body as a single body. The intermediate interval is a transitional interval for smoothly connecting the initial interval and final interval without involving any substantial peak or dip in the deceleration. Computer simulations have verified that such a waveform for the vehicle body deceleration results in a smaller vehicle occupant deceleration than the case of a constant deceleration (rectangular waveform) for a given amount of deformation of the vehicle body (dynamic stroke).
[0008] According to the conventional vehicle body structure, the vehicle body components of the crushable zone start deforming from a part having a relatively small mechanical strength immediately after the crash, and a part thereof having a relatively high mechanical strength starts deforming thereafter. As a result, the waveform of the crash reaction or the vehicle body deceleration is small in an early phase, and then gets greater in a later phase so that the vehicle occupant deceleration cannot be adequately reduced. To eliminate such a problem, it has been proposed to obtain a prescribed amount of reaction force by making use of the collapsing of the side beams and to maintain a stable reaction by providing a plurality of partition walls in the side beams (Japanese patent laid-open publication (kokai) No. 07-101354). However, such previous proposals can only maintain the vehicle body deceleration at an approximately constant level at most, and are unable to provide a more effective deceleration waveform.
[0009] To minimize the adverse effect of the resiliency of the seat belt, it is known to provide a pretensioner device in association with the seat belt to positively tension the seat belt at the time of a vehicle crash. According to another previously proposed structure, at least one of the anchor points of the seat belt is attached to a member which undergoes a movement relative to the remaining part of the vehicle which tends to increase the tension of the seat belt in an early phase of a vehicle crash. Such devices are beneficial in reducing the maximum level of deceleration acting on the vehicle occupant at the time of a vehicle crash, but a device capable of more precise control of the vehicle occupant deceleration is desired.
[0010] Referring to FIG. 7, the vehicle occupant deceleration G 1 and vehicle body deceleration G 2 correspond to the input and output of a transfer function representing a two-mass spring-mass system consisting of the mass Mm of a vehicle occupant 2 , a spring (such as a seat belt), and a vehicle body mass Mv. More specifically, the vehicle body deceleration G 2 can be given as a second-order differentiation of the coordinate of the vehicle body mass Mv with respect to time.
[0011] However, in an actual automotive crash, if a three-point seat belt is used, the shoulder belt portion of the seat belt which can be considered as a spring engages the chest of the vehicle occupant corresponding to the center of the vehicle occupant mass Mm so that the shoulder belt portion can be considered as consisting of two springs, one extending between the chest and shoulder anchor, the other extending between the chest and the buckle anchor.
[0012] If the seat belt is entirely incorporated to the seat, the shoulder anchor and buckle anchor move as a single body, and the two parts experience an identical deceleration. In such a case, it can be assumed that the seat belt can be given as a composite of two springs, and the deceleration acting on the shoulder anchor and buckle anchor is identical to the input to the two-mass spring-mass system or the vehicle body deceleration.
[0013] Now, suppose if the buckle anchor point is fixedly attached to the vehicle body while the shoulder anchor is capable of movement relative to the vehicle body as an example in which the two anchor points undergo different movements relative to the vehicle body. In such a case, because the shoulder anchor and buckle anchor experience different decelerations, the springs cannot be simply combined or the decelerations acting on the shoulder anchor and buckle anchor cannot be simply equated to the vehicle body deceleration.
[0014] Meanwhile, the external force acting on the chest wholly consists of the force received from the seat belt. Therefore, if the time history of the load acting on the seat belt in the direction of deceleration agrees with the time history of the spring load in the two-mass spring-mass system, the chest receives the same deceleration waveform as the response of the vehicle occupant mass of the two-mass spring-mass system to the optimum waveform of vehicle body deceleration. This enables the vehicle occupant to reach the ride-down state in which the vehicle occupant is restrained by the seat belt substantially without any delay and the relative speed between the vehicle body and vehicle occupant is zero (no difference between the vehicle occupant deceleration G 1 and vehicle body deceleration G 2 ).
[0015] To achieve a time history of the seat belt that produces such a state, it suffices if the time history of the average deceleration of the shoulder anchor and buckle anchor (or vehicle body) is equal to the optimum waveform of the vehicle body deceleration. Introducing the concept of the waveform of average vehicle body deceleration allows an identical result in reducing the vehicle occupant deceleration as controlling the vehicle body deceleration so as to achieve the optimum waveform to be achieved.
[0016] The early rise in the tension of the seat belt to apply the deceleration to the vehicle occupant from an early stage can be most conveniently provided by a pyrotechnical actuator typically using a propellant. Pyrotechnical actuators are widely known in such applications as vehicle air bags and pretensioners. However, it was found due to the nature of its structure which relies on the generation of high pressure gas that such an actuator alone may not be able to produce a desired time history of the deceleration of the vehicle occupant. It was found that the provision of inertia mass prevents an oscillatory movement to the moveable end or vehicle occupant during the activation of the actuator. The inventors have discovered that such a problem can be overcome by adding a suitable amount of mass to the actuator end of the seat belt in combination with a cushioning member.
BRIEF SUMMARY OF THE INVENTION
[0017] In view of such problems of the prior art, a primary object of the present invention is to provide a vehicle occupant protection system which can improve the protection of the vehicle occupant at the time of a vehicle crash for a given dynamic stroke or a deformation stroke of a front part of the vehicle body.
[0018] A second object of the present invention is to provide a vehicle occupant protection system which can maximize the protection of the vehicle occupant with a minimum modification to the existing vehicle body structure.
[0019] A third object of the present invention is to provide a vehicle occupant protection system which can maximize the protection of the vehicle occupant without increasing the weight of the vehicle body or taking up any significant amount of space in the passenger compartment.
[0020] According to the present invention, such objects can be accomplished by providing an automotive vehicle occupant protection system, comprising: a seat supported on a floor of a vehicle body; a seat belt provided in association with the seat and including a moveable end; an actuator connecting the moveable end of the seat belt to a part of the vehicle body to selectively remove a slack from the seat belt; and a control unit including a deceleration sensor for detecting a frontal vehicle crash meeting a prescribed condition; the actuator including a mass member attached to the moveable end of the seat belt, an arrangement for amplifying an inertia effect of the mass on a movement of the moveable end of the seat belt, and a main actuator unit adapted to move the mass member in a direction to remove a slack from the seat belt immediately upon detection of a frontal vehicle crash.
[0021] Thus, upon detection of a crash, the main actuator which typically consists of a pyrotechnic actuator increases the restraint of the seat belt by moving the moveable end of the seat belt so that a deceleration greater than the average deceleration (vehicle deceleration) is produced in the vehicle occupant. Because the seat belt and vehicle occupant behave as a spring mass system, an oscillatory motion of the vehicle occupant tends to be induced. Such an oscillatory motion is obviously undesirable to the end of minimizing the peak value of the deceleration acting on the vehicle occupant. Therefore, according to the present invention, an increased amount of mass is added to the spring mass system to prevent any such undesirable oscillatory motion of the moveable end of the seat belt or the vehicle occupant from occurring. The provision of the mass member also facilitates the control of the time history of the output of the actuator to best achieve the desired acceleration control for the vehicle occupant.
[0022] The system preferably includes a cushioning member for decelerating a movement of the moveable end following a certain initial travel of the moveable end. Thus, after the moveable part has moved by a prescribed distance, the movement is prevented by the cushioning member and an opposite deceleration is produced in the vehicle occupant so that the vehicle occupant and vehicle body move as a single body in a final phase of the crash, and decelerate at the average deceleration. This achieves a waveform of vehicle body deceleration suitable for the minimization of the deceleration of the vehicle occupant.
[0023] The anchor points may be provided in appropriate parts of the vehicle body, but all or some of them may be provided on parts of the seat. According to a preferred embodiment of the present invention, to obtain a highly predictable result, the seat belt may comprise three anchor points including a shoulder anchor, a seat bottom side anchor provided near a seat bottom on a same side as the shoulder anchor, and a buckle anchor provided near the seat bottom on an opposite side of the shoulder anchor.
[0024] Preferably, the mass member comprises a flywheel which provides a large amount of inertia without taking up any significant amount of space. The actuator may comprise wire including a first end connected to a working end of the main actuator unit, an intermediate part wound around a rotary shaft having the flywheel integrally or otherwise functionally connected thereto, and a second end attached to the moveable end of the seat belt. In particular, by choosing the rotary shaft to have an appropriate diameter, it is possible to magnify the inertia effect of the flywheel at will. The inertia effect gets greater as the diameter of the rotary shaft is reduced.
[0025] According to a particularly preferred embodiment of the present invention, the main actuator unit includes a cylinder integrally attached to a side of a seat bottom of the seat, a piston slidably received in the cylinder, and a pyrotechnic gas generator provided on one end of the cylinder, the wire being attached to the piston. However, it is also possible to use other sources of energy for the actuator including pre-loaded springs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Now the present invention is described in the following with reference to the appended drawings, in which:
[0027] [0027]FIG. 1 is a schematic side view of the outline of the vehicle body structure fitted with a vehicle occupant protection system embodying the present invention;
[0028] [0028]FIG. 2 is an overall perspective view of the seat fitted with the vehicle occupant protection system according to the present invention;
[0029] [0029]FIG. 3 is an enlarged sectional view of the vehicle occupant protection system;
[0030] [0030]FIG. 4 a is a schematic view of the vehicle body in an initial phase of the crash;
[0031] [0031]FIG. 4 b is a schematic view showing an intermediate phase of the crash;
[0032] [0032]FIG. 4 c is a schematic view showing a final phase of the crash;
[0033] [0033]FIG. 5 a is a sectional view showing the state of the actuator in an initial phase of the crash;
[0034] [0034]FIG. 5 b is a sectional view showing the state of the actuator in an intermediate phase of the crash;
[0035] [0035]FIG. 5 c is a sectional view showing the state of the actuator in a final phase of the crash;
[0036] [0036]FIG. 6 is a diagram showing the waveforms of the vehicle occupant deceleration and vehicle body deceleration; and
[0037] [0037]FIG. 7 is a conceptual diagram showing the relationship between the vehicle occupant, vehicle body and seat belt at the time of a vehicle crash.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] [0038]FIG. 1 schematically illustrates the overall structure of a vehicle incorporated with a vehicle occupant protection system embodying the present invention. The vehicle occupant protection system includes a seat belt 3 for restraining the vehicle occupant 2 to the seat 1 . As shown in FIG. 2 also, the seat belt 3 has three anchor points, and an end of the seat belt is connected to a retractor 4 integrally provided in a shoulder part of the seat 1 , another end fixedly attached to a side of the seat bottom on the same side as the shoulder anchor, and an intermediate part having a tongue plate that is latched to a buckle 6 attached to the side of the seat bottom on the other side of the shoulder anchor. Therefore, the vehicle occupant 2 who is seated in the seat 1 is integrally restrained to the seat 1 by the seat belt 3 . The seat 1 is attached to a floor 5 via seat rails la so as to be adjustable in the fore-and-aft direction.
[0039] An actuator 8 is integrally attached to a side of the seat bottom of the seat 1 . As also shown in FIG. 3, the actuator 8 comprises a cylinder 8 a extending in the fore-and-aft direction, a piston 8 b coaxially received in the cylinder 8 a , a cylinder cap 8 c integrally attached to an end (rear end with respect to the vehicle body) of the cylinder 8 a , and a gas generator 8 d connected to the cylinder cap 8 c so as to communicate with the interior of the cylinder cap 8 c . The front end of the cylinder 8 b in this case opens out to the atmosphere. The actuator 8 is integrally provided with a bracket 8 j by which the actuator 8 is bolted down to the frame of the seat bottom.
[0040] To the piston 8 b is connected an end of wire 9 which extends out of an opening 8 e provided in the rear end of the cylinder cap 8 c . The outer end of the wire 9 is wound around a rotary shaft 10 a which is rotatably supported behind the actuator 8 and is integrally and coaxially provided with a flywheel 10 , and then further extends to an extreme end which is connected to a base end of the buckle 6 . Therefore, as the piston 8 b is driven forward by the gas generator 8 d and the wire 9 is pulled forward as a result, the wire 9 pulls the buckle 6 in the direction to increase the tension of the seat belt 3 or the restraint on the vehicle occupant 2 while the intermediate part of the wire 9 wound around the rotary shaft 10 a causes the flywheel 10 to rotate. The intermediate part of the wire 9 and rotary shaft 10 a are received in a casing 8 f which is attached to the rear end of the cylinder cap 8 c.
[0041] The outer circumferential surface of the piston 8 b is provided with a reversing preventing ring 8 g which allows the forward movement of the piston 8 b by inclining itself to one side but prevents the rearward movement of the piston 8 b by wedging into the inner circumferential surface of the cylinder 8 a.
[0042] A tubular cushioning member 8 i is provided on an outer end of an opening 8 h of the casing 8 f facing the buckle 6 in a coaxial arrangement, and the free end of the tubular cushioning member 8 i opposes the base end of the buckle 6 defining a gap of a prescribed dimension d therebetween. A bellows cover 11 covers the wire 9 connected to the base end of the buckle 6 and the tubular cushioning member 8 i , and extends between the base end of the buckle 6 and the opposing end of the casing 8 f . The bellows cover 11 has an adequate rigidity to support the buckle 6 in a substantially fixed manner, but demonstrates a flexible that allows the bellows cover 11 to axially compress so as to accommodate the movement of the buckle 6 in the direction to increase the tension of the seat belt 3 .
[0043] The actuator 8 described above thus comprises the cylinder 8 a , piston 8 b , cylinder cap 8 c and gas generator 8 d , and is designed to provide a primary acceleration that increases the restraint on the vehicle occupant 2 . The tubular cushioning member 8 i provides a secondary acceleration which controls the acceleration provided by the actuator 8 as will be described hereinafter.
[0044] To the gas generator 8 d is connected a signal line from a control unit 12 mounted to an appropriate part (such as the floor 5 ) of the vehicle body and incorporated with a crash sensor which, for instance, may consist of a G sensor. The crash sensor provides a crash detecting signal to the gas generator 8 d when a crash meeting a prescribed condition is detected. In response to a crash detecting signal, the gas generator 8 d instantaneously produces expanding gas which is then introduced into the cylinder cap 8 c.
[0045] Referring to FIGS. 4 a to 4 c and 5 a to 5 c, the mode of operation of the embodiment of the present invention is described in the following by taking an example of a frontal crash onto a fixed structure.
[0046] [0046]FIG. 4 a shows a state of an initial phase (interval a of FIG. 6) immediately following the occurrence of a crash. The front end of the vehicle body collapses, and the front ends of side beams 13 integral with the floor 5 undergo a compressive deformation as shown in the drawing. The crash sensor incorporated in the control unit 12 detects the vehicle body deceleration resulting from the vehicle crash exceeding a prescribed intensity, and the control unit 12 judges the condition that is produced. If the control unit 12 judges that the condition meets the prescribed criterion, the gas generator 8 d is activated.
[0047] The expanding gas produced from the gas generator 8 d is introduced into the cylinder cap 8 c as indicated by the arrows in FIG. 5 a , and the pressure of the expanding gas pushes the piston 8 b in the forward direction with respect to the vehicle body. As a result, the buckle 6 which is connected to the piston 8 b via the wire 9 starts moving in the direction to increase the restraint of the seat belt 3 on the vehicle occupant 2 while the rotary shaft 10 a and flywheel 10 start rotating. The movement of the buckle 6 causes the bellows cover 11 to collapse, and accelerates as the pressure of the generated gas increases.
[0048] The early rise in the tension or load acting on the seat belt 3 corresponds to an increase in the restraint on the vehicle occupant 2 and the deceleration of the vehicle occupant from an early phase of the crash. The resulting rise in the seat belt load is earlier than that provided by a conventional seat belt which is simply secured at three anchor points in restraining the vehicle occupant from being thrown forward under the inertia force. Therefore, the deceleration of the vehicle occupant is made to rise from a very early part of the crash as indicated by G 1 in FIG. 6.
[0049] [0049]FIG. 4 b shows a state in an intermediate phase of the crash (interval b of FIG. 6). As the collapsing of the front part of the vehicle body progresses, the piston 8 b of the actuator 8 moves further forward with respect to the vehicle body as indicated in FIG. 5 b . As the piston 8 b moves further forward, the base end of the buckle 6 eventually collides with the cushioning member 8 i , and this decelerates the movement of the buckle 6 , thereby producing an opposite (forward with respect to the vehicle body) acceleration to the vehicle occupant. This produces an effect equivalent to that produced by an acceleration directed in the opposite direction to the deceleration resulting directly from the crash acting on the passenger compartment. To better achieve such an effect, the effective mass of the flywheel 10 and diameter of the rotary shaft 10 a as well as the acceleration of the flywheel 10 at the time of colliding with the cushioning member 8 i are appropriately adjusted. It is preferable to design the properties (such as elongation and spring properties) of the seat belt 3 and the properties (such as impact absorbing property) of the cushioning member 8 i so that the speed and deceleration of the vehicle occupant 2 coincide with those of the vehicle body (seat 1 ) upon completion of the acceleration in the opposite direction acting on the buckle 6 during this intermediate phase.
[0050] [0050]FIG. 4 c shows a state of a final phase (interval c of FIG. 6) of the crash. During the final phase, the movement of the buckle 6 is further decelerated by the cushioning member 8 i , and the piston 8 b eventually comes to a complete stop. As a result, the buckle 6 also stops moving any further, and is retained at this position until the end of the vehicle crash by virtue of a reversing preventing ring 8 g.
[0051] During this final phase, once the speed and deceleration of the vehicle occupant agree with those of the vehicle body (seat 1 ), there is no relative movement between the vehicle occupant 2 and vehicle body (seat 1 ), and the vehicle occupant 2 continues to decelerate as a single body with the vehicle body (seat 1 ). In other words, the maximum value of the vehicle occupant deceleration G 1 can be reduced by achieving a ride down state in which the relative speed between the vehicle occupant 2 and vehicle body (seat 1 ) is minimized and the difference between the vehicle occupant deceleration G 1 and vehicle body deceleration G 2 is minimized.
[0052] Thus, the process described above can substantially reduce the vehicle occupant deceleration by controlling the deceleration produced in the buckle 6 so as to follow the optimum deceleration waveform or by designing the actuator 8 so as to produce the optimum deceleration waveform.
[0053] Thus, according to the foregoing embodiment, upon detection of a crash, the main part of the actuator consisting of a pyrotechnical actuator increases the restraint of the seat belt by moving the moveable part provided on the seat serving as a part of the vehicle body so that the vehicle occupant is allowed to experience an early rise in deceleration. Then, after the moveable part has moved by a prescribed distance, the movement is prevented by the cushioning member and an opposite deceleration is produced in the moveable part so that the vehicle occupant and vehicle body move as a single body in a final phase of the crash, and decelerate at the average deceleration. This achieves a waveform of vehicle body deceleration suitable for the minimization of the deceleration of the vehicle occupant. As a result, not only a substantial reduction in the vehicle occupant deceleration can be achieved with a smaller vehicle body deformation (dynamic stroke) but also the displacement of the vehicle occupant in the passenger compartment relative to the vehicle body can be reduced even more than possible by providing a load limiter in the restraining device to reduce the vehicle body deceleration. The smaller displacement of the vehicle occupant reduces the possibility of a secondary collision.
[0054] When an end of the seat belt is attached to the seat, and an intermediate part of the seat belt is attached to the moveable part via a buckle, the vehicle occupant and seat can be joined integrally to each other by using a conventional three-point seat belt incorporated to a seat so that the cost of the system can be minimized without requiring any substantial change to the existing system.
[0055] Although the present invention has been described in terms of a preferred embodiment thereof, it is obvious to a person skilled in the art that various alterations and modifications are possible without departing from the scope of the present invention which is set forth in the appended claims. For instance, all or some of the anchor points may be provided on parts of the vehicle body other than those on the seat. The actuator also may consist of actuators other than pyrotechnic actuators such as spring loaded actuators without departing from the spirit of the present invention.
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An end of a seat belt is connected to an actuator that can selectively remove a slack from the seat belt. The actuator includes a main actuator unit, a flywheel which provides a maximum inertia effect for a given space, and a cushioning member for decelerating a movement of the moveable end of the seat belt following a certain initial travel of the moveable end. The main actuator unit produces an early rise in the vehicle occupant deceleration, and the cushioning member smoothly connects the time history of the vehicle occupant deceleration to a ride-down condition whereby the deceleration acting on the vehicle occupant is favorably spread over time, and the maximum level of the deceleration can be minimized. The flywheel contributes to a favorable shaping of the time history of the vehicle occupant deceleration.
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TECHNICAL FIELD
[0001] The invention relates to a damp protection arrangement for a space confined by floor, roof and wall portions in a building. The invention also relates to a method of protecting such a space from damp.
BACKGROUND
[0002] The problems related to damage from damp are serious when, as is common in Nordic countries, the houses are constructed with hollow spaces in floor structures and walls. Mildew damage as well as chemical emissions arise if water enters these hollow spaces. This problem grew when the houses were made tight in the beginning of the seventies. Thereby also the natural ventilation that occurs in floor structures and walls was also removed.
[0003] In Sweden alone the cost for damp damage is equivalent to about a half billion A smaller part of this cost includes the cost of repairing leakage such as fractured pipes etc. The main part of this cost is in the work in connection with tearing up, drying and reconstructing the spaces, for example bathrooms, that are subjected to water damage. This is in spite of the leak possibly being located at a quite different place than the bathroom. Currently a problem is also that many rather newly installed bathrooms have to be teared up and dried out solely of the reason that the impermeable layers of an upstair neighbor are leaking.
[0004] The insights forming the basis of the invention may be expressed as follows:
If a water damage were observed on an early stage, large costs would be saved. If the damp could be dried out without having to tear away walls and floor structures, still more costs would be saved. If the damp within the walls could be ventilated away in a controllable manner, emissions causing illness would also be ventilated away, and the number of bad houses would decrease. If the necessary measures resulted in cost savings they would be employed. If the necessary measures did not use up space, they would also be used. If the necessary measures were simple, the craftsmen would adopt them. If the necessary measures can be applied within current regulations, there are no formal obstacles to apply them.
PRIOR ART
[0012] It is known from SE 9701542-4 C2 to install board elements mounted spaced from walls and floor for the purpose of ventilating a room, so that between the walls and the floor a ventilation space is formed for a through flow of air. This technology is used in order to ventilating away detrimental concentrations of damp and gases, such as radon gas, in a preventive purpose.
[0013] For wet spaces such as bathrooms and the like, it is known from SE 8203579-1 B to ventilate a damp sub floor by an impermeable, damp proof board at a space from the floor, which board extends upwards along and also at a distance from a lower portion of an adjacent wall.
DISCLOSURE OF THE INVENTION
[0014] An object of the invention is to further develop the prior art and provide a low-cost, simple and space-saving solution to the problems of damp, particularly but not exclusively in wet spaces.
[0015] In accordance with an aspect of the invention, the damp protection arrangement comprises the following features in combination:
A damp permeable first layer structure inside the space comprising at least one wall portion of said portions.
[0017] Thereby, portions lying behind such as insulation in the building may be defined and be provided a well defined flow-promoting smooth face of an air gap capable of conveying damp mixed up with possibly harmful substances.
A second layer structure, inside the space covering at least the first layer structure.
[0019] Thereby also a smooth face may be defined, i.e. the opposite face of the air gap. The second layer structure may be optionally permeable to damp for being suitable in a wet space, or permeable to damp for being suitable for other types of spaces that run the risk of being subjected to damp damages.
A continuous air gap, separated from the space defined between the first and the second layer structure.
[0021] Thereby an insulated passage is provided for accumulation and exposure of damp, for interaction with an air flow and for transport of resulting damp air in the space.
An air inlet at a lower level in the space and communicating with the air gap.
[0023] Thereby a passage may be provided for transport of dry air to the air gap.
An air outlet at a higher level in the space and communicating with the air gap.
[0025] Thereby a passage may be provided for transport of the damp air out of the space.
A heating source inside the air gap for providing an air flow in the air gap between the inlet and the outlet and capable of dehumidifying the layer structures.
[0027] By the heating source being located inside the air gap, the heating source can directly heat the dry air, so that the dry air will have a high tendency to attract the damp or humidity, possibly mixed up with harmful substances, and bring the resulting humid air into motion upwards to the outlet and out of the building.
[0028] Other features and advantages of the present invention are apparent from the claims and the following detailed description of exemplary embodiments.
BRIEF DESCRIPTION OF THE DRAWING
[0029] FIG. 1 is a diagrammatic sectional cutaway view of a building having a space provided with a damp protection arrangement according to the invention;
[0030] FIG. 2 is a detail view in larger scale of a first encircled area of FIG. 1 ;
[0031] FIG. 3 is a detail view in larger scale of a second encircled area of FIG. 1 ; and
[0032] FIG. 4 is a detail view in larger scale of a third encircled area of FIG. 1 .
DETAILED DESCRIPTION OF EMBODIMENTS
[0033] Generally referenced by 10 in FIG. 1 is a portion of a building having a floor portion 12 , a ceiling portion 14 and wall portion 16 defining a wet space 24 . While the damp protection arrangement in the exemplary embodiment is described in connection with a wet space, and primarily may be applied to wet spaces, the damp protection arrangement according to the invention, as the invention is defined in the claims, may also be applied to other spaces that run the risk of being subjected to damp damages, for example spaces directly below a leaking roof. For the access to the wet space, also shown is a door 26 .
[0034] The floor, ceiling and wall portions 12 , 14 , 16 may be of varying construction. While the invention may be applied on pure concrete structures, it is primarily intended for portions, for example infill portions having battens and beams (not shown) defining hollow spaces that in turn may be filled with heat insulating materials 20 and 22 respectively. Such portions are particularly sensitive to damp damages.
[0035] According to the invention, inside the wet space 24 confined by the floor, ceiling and wall portions 12 , 14 , 16 , a damp protection arrangement is provided, comprising a damp permeable layer structure 70 , 80 and a damp impermeable layer structure 40 , 60 that define a continuous air gap 50 therebetween. It is to be noted that FIG. 1 shows the damp protecting arrangement only in illustrative purpose, showing excessive thicknesses and spacings between the layer structures. A damp protection arrangement according to the invention needs no more space than a conventional original layer construction in a wet space. In principle only the thin air gap and the thin damp permeable layer 80 are added in the wall portions 16 , while in the floor portion 12 only the air gap is added; in conventional wet space walls often double layers of gypsum wall board is used, were the added gypsum layer is about as thick as the air gap. Doubled gypsum wall board layers are, however, unsuitable together with the present invention, as the resulting doubled paper layers between the boards suck up water and acts as obstructing to the dehumidification.
[0036] While the layer structures in the embodiment shown are indicated as stretching over all floor and wall portions, 12 , 16 , they may be used to a varying extent in many combinations depending on varying constructions of the floor and wall portions in the particular case. In an extreme case, for example comprising a concrete building structure having only one differing wall portion that is especially sensitive to damp damage, it may be sufficient to use the layers structures 60 , 80 only at the corresponding wall face in the wet space (not shown). In the normal case, however, the layer structures extend also over the floor portion 12 of the wet space 24 and over all wall portions. Directly to the ceiling portion 14 there should not be any layer structure at all as that structure then would run the risk of keeping damp in the corresponding concrete structure or in the insulating material 20 . In the example shown, a damp permeable ceiling layer 90 needs to be spaced from the ceiling portion 14 to keep the continuous air gap 50 separated or insulated from the damp protected wet space 24 .
[0037] As is more clearly apparent from FIG. 2 , the damp permeable layer structure 80 adjacent to a wall portion 16 , comprises a damp permeable layer 82 . The outer face of the damp permeable layer 82 serves to form a preferably flat face of the air gap 50 and to keep possible insulations 22 in place in the wall portion 16 lying behind. It is however, within the scope of the appended claims also conceivable that the damp permeable layer structure is composed of the present wall portion only, with or without insulation and without any supplementary layer. The damp permeable layer 82 is however in the embodiment shown preferably a cloth of geotextile or a board of cement; also other materials may however be suitable.
[0038] The layer structures 16 adjacent to the wall portion 16 comprises from the inside and out to the wet space 24 a supporting layer 66 , a damp impermeable layer 64 and a surface layer 62 . The support layer 66 , the inner face of which serves to form the opposite flat face of the air gap 50 and the outer face of which accordingly carries the impermeable layer 64 and the surface layer 62 , is a board of wet room gypsum in the exemplary embodiment but can also consist of other supporting board materials. The impermeable layer 64 is a water tight moisture barrier of a known type applied to the outer surface of the support layer 66 . On the impermeable layer 64 the surface layer is finally applied in a conventional manner, in the exemplary embodiment a layer of tiles together with fastening and joining compounds.
[0039] As is more clearly apparent from FIG. 3 , the damp permeable layer structure 70 adjoining a floor portion 12 , comprises a damp permeable layer 72 . The top face of the damp permeable layer 72 serves to form a flat face of the air gap 50 and to keep possible insulation 20 in place in the underlying floor portion 12 . In the exemplary embodiment, the damp permeable layer 72 is a conventional—in case of a reconstruction possibly already present—sub floor layer, for example made of floor boards based on wood fibers, but also other materials may be suitable. In order to increase the damp permeability in relatively impermeably sub floor layers, ventilating bores 74 may be drilled by using a suitable bore diameter and distribution over the floor surface, as indicated by 15 lines in FIG. 3 . The bores 74 may be covered by a vapour permeable but water impermeable cloth 76 .
[0040] The layer structure 40 adjoining the floor portion 12 , in the exemplary embodiment comprises from the inside and out to the wet space 24 , a support layer 48 , a layer 46 providing floor inclination, an impermeable layer 44 and a surface layer 42 . The support layer 48 the inside of which serves the purpose of forming the opposite flat side of the air gap 50 and the outside of which accordingly supports the remaining layers 46 , 44 , 42 , in the exemplary embodiment for example a conventional damp resistant floor board of a gypsum type, but may also consist of other supporting board materials. The layer 46 that provides the inclination to the floor is a filling compound 46 of a known type. The impermeable layer 44 is a moisture barrier of a known type applied on the top surface of the layer 46 . On the impermeable layer 44 is finally applied the surface layer 62 in a conventional manner, in the exemplary embodiment a clinker layer together with fastening and joining compound.
[0041] The gap width of the air gap 50 that typically can be about 1 cm, is maintained between adjoining layer structures 40 , 70 and 60 , 80 respectively, by spacers 52 such as elongated strips or spars of wood material. Other types of spacers may however also be usable. As is indicated in FIG. 3 by the broken spacer 52 in the air gap 50 , the spacers at the floor portion 12 may be arranged by interspaces in the longitudinal as well as in the transverse direction in the floor plane in order that the air flow from the air gap 50 at the floor portion 12 may be distributed to mutually perpendicular air gaps 50 at the wall portion 16 .
[0042] To heat the air in the air gap 50 and to increase the air flow that is indicated by filled arrows on the drawing, in the embodiment shown there is provided a heating cable 54 ( 2 ) at a low level inside the portion of air gap 50 that extends along the wall portions 16 . The heating cable 54 is in a suitable manner, for example by cable clamps 56 , attached to the outside of the damp permeable layer 80 , and runs horizontally across the air flow along the entire air gap 50 . As is indicated in FIG. 1 , the heating cable is connected to the electric network (not shown) of the building 10 through an electric cable 100 . An electronic unit 102 may in a manner known per se be provided with a switch for switching the heating power on and off, and possibly also be provided with equipment capable of controlling the heating power.
[0043] As is further indicated in FIG. 1 , the damp protection arrangement can also be adapted to monitor the state of the air gap 50 and be brought into function by itself: In the air gap 50 is a sensor 104 adapted to sense the presence of damp or moisture in the air gap 50 and to signal the result through a signal line 106 to the electronic unit 102 so that the unit 102 is capable of turning on and off and/or controlling the heating power in response to the signals from the sensor 104 .
[0044] While the inlet for dry air to the air gap 50 may be arranged in other ways at a low level in the wet space 24 , in the embodiment according to FIG. 4 an air inlet 30 extends to the air gap 50 in the level of the air gap 50 through a threshold 28 at the door 26 to the wet space 24 . The air inlet 30 can consist of a plurality of transverse openings or an elongated gap or slot in the threshold 28 and have an inlet filter (not shown) preventing inlet of dust or the like.
[0045] In the embodiment shown in FIG. 1 , the outlet for air from air gap 50 comprises a piece 92 of tubing extending from the inside of the wet space 24 through the ceiling layer 90 to an exhausted passage 96 in the building 10 . The portion of the piece 92 of tubing that is insulated from the wet space 24 by the ceiling layer 90 is provided with perforations 94 through which the air from air gap 50 can be sucked out to the exhausted passage 96 and out of the building 10 .
[0046] Pipes for water and sewer to the wet space 24 are insulated in the passage through the air gap 50 in a suitable manner, for example by sleeves of expanded plastics material (not shown).
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A damp protection arrangement for a space confined by floor, ceiling and wall portions in a building and comprising the following components: a damp permeable first layer structure ( 80 ), inside the space comprising at least one wall portion ( 16/80 ) of said portions; a second layer structure ( 60 ), inside the space covering at least the first layer structure ( 60/80 ); a continuous air gap ( 50 ), separated from the space and defined between the first and the second layer structures; an air inlet at a lower level in the space and communicating with the air gap ( 50 ); an air outlet at a higher level in the space and communicating with the air gap; and heating source ( 54 ) inside the air gap ( 50 ) for providing an air flow in the air gap between the inlet and the outlet and capable of dehumidifying layer structures.
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BACKGROUND OF THE INVENTION
This invention relates to a device for controlling weft yarn insertion, or a warp stop motion device, for use in continuous weft feed looms, without shuttles.
The purpose of the device according to the invention is to stop the loom and emit a corresponding signal, not only each time there is a breakage or absence of a weft yarn -- which is already efficiently obtained by various known devices -- but also whenever the undesired insertion of double wefts occurs.
It is known that, in loom operation, the weft yarn often breaks or is missing, and, to overcome this phenomenon, warp stop motion devices are used for controlling the breakage of the weft thread, in various universally known mechanical, electrical or electronic versions. It can however also happen that, especially with hairy yarn, the weft yarn presented to the gripper of a shuttleless loom takes along with it another weft yarn, which is thus simulaneously inserted, with serious damage to the fabric. This phenomenon is favoured by the fact that the weft yarns ready to be inserted are subjected to very low stretching and, thus, the action of the yarn fluff is sufficient to hook two yarns together.
It can also happen that the perforated tape, controlling weft insertion by means of the presenting device, may get damaged, in which case, one or more wrong wefts will be presented to the gripper in addition to the required weft yarn. In this case, as the perforated tape is generally in the form of an endless loop, the error becomes cyclic with serious damage to the fabric.
The invention relates therefore to an electronic control device being adapted, at each weft insertion, to check the number of wefts being inserted or the possible breakage of the wefts, and to immediately stop the loom -- in the event or irregularities -- in sufficient time to repair the damage, hence representing considerable progress over the known art.
SUMMARY OF THE INVENTION
This device is substantially characterized in that it comprises a plurality of transducers, each activated by a weft yarn and being adapted to feed signals to a logic network when the yarn is in movement, and means, downstream of said logic network, operated by the signals emitted by said network and adapted to activate a device for stopping the loom and providing a signal, said logic network comprising means for storing a predetermined law of insertion of the individual weft yarns corresponding to a certain weaving operation on the loom, and for comparing with said law the actual weft insertions detected by the transducers. In the logic network, the means for storing and comparing preferably consist of a voltage divider, comprising on one side a plurality of resistors, one for each transducer, disposed in parallel, and on the other side, a single comparison resistor, so as to obtain an output signal which is above or, respectively, below a normal predetermined value, when the actual weft yarn insertions detected by the transducer do not coincide with those required, or, respectively when there is no weft yarn insertion. Furthermore, each of said resistors as well as the comparison resistor of the voltage divider, comprise a first stably connected resistor and a second resistor, equal to the first and adapted to be connected thereto by means of a switch, adapted to be manually operated during programming of the weft yarn insertion law, corresponding to the weaving operation to be performed on the loom. To make it at once evident to the operator whether the stopping of the loom is due to breakage of a weft yarn or to the insertion of too many weft yarns, the device for stopping the loom and providing a signal fulfills this last purpose by lighting a lamp, either continuously or intermittently, according to which of said irregularities is responsible for activating the device.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in further detail, to illustrate more fully its characteristics and advantages, with reference to one embodiment thereof given by way of example and illustrated in the accompanying drawings, in which:
FIG. 1 is a block diagram of the warp stop motion device according to the invention; and
FIG. 2 represents the logic network used in the device according to the illustrated embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to the drawings, FIG. 1 shows that the device according to the present invention comprises a certain number (eight in the drawing) of systems, adapted to detect the movement of the weft yarns by means of transducers, which supply an electric output signal. Said transducers may base their operation on photoelectric, electromagnetic, piezoelectric or condenser principles, according to the prechosen embodiment. Use of the piezoelectric crystals principle may however be recommended. In this case, the weft yarn skims a ceramic tube, to which a plate of piezoelectric material is mechanically fixed. The movement of the yarn sliding on the ceramic tube produces a noise which is transformed into an electric signal by the piezoelectric lamina. There are as many transducers 1 as there are weft yarns to be controlled (a maximum of eight in the case of normal gripper looms, as indicated). In the device according to the invention, an amplifier 2 is associated to each transducer 1, said amplifier being fed by the signals originating from the transducer and adapted to amplify, rectify and integrate said signals. The transducers 1 and amplifiers 2 must possess specific characteristics subject to very strict requirements, as is explained in greater detail hereinafter; the signals which they produce and elaborate arrive at a programmable logic network 3, the purpose of which is to compare the input signals, representing the actual weft yarn insertions detected by the transducers with the predetermined insertion law stored in the network itself, and to supply a direct current output signal, the value of which will vary from the normal predetermined value in the event of irregularities, and said value being different according to whether the weft yarn is broken or whether too many weft yarns have been inserted. This logic network, which may be constructed in various ways, by means of analogic or digital electronic systems, is shown in FIG. 2 in one of its preferred versions, and is described in detail hereinafter. The output from the logic network 3 is connected to two blocks 5 and 6 which, by means of a further block 7, control the stopping of the loom and the continuous or intermittent lighting of a warning lamp. The block 6 acts independently, while the block 5 is adapted to operate only upon receipt of a gate signal from a further block 4, controlled by the general movement of the loom by way of a cam.
The logic network 3, shown in FIG. 2, consists of a voltage divider. In said network, the reference numbers 17 to 24 indicate the eight electronic switches each formed by a unit comprising an associated set of elements 1 and 2 as seen in Fig. 1; these switches are open when the respective weft yarn is at rest and are closed when said yarn is inserted into the warp.
The reference +VA indicates the supply voltage of the voltage divider common to all switches 17 to 24, and VO indicates the output signal of the block 3, being drawn through a common connection to which each of the switches 17 to 24 is connected through a respective resistor 10. The said common connection is also constantly connected to earth at M through a resistor 12. Resistors 11 may be connected in parallel to the resistors 10 by closing the switches 14, 15 (shown open), while a resistor 13 may be similarly connected in parallel to the resistance 12 by closing a switch 16 (also illustrated open). The resistors 10 and 11 have the same value; also the resistors 12 and 13 have the same value. The resistors 11 are shown only in correspondence of the electronic switches 17 and 18, but they could also be provided for any other of the switches 19 to 24.
A brief description will now be given of the operation of the device, the basic scheme of which has been described.
A first case is that in which the loom operates in such a manner that all the wefts are inserted individually. In this case the programming of the network 3 consists of setting all switches 14, 15, 16 in the open position. In this condition, if a single weft is inserted at a time, with the loom operating regularly, the particular electronic switch of the series 17 to 24, corresponding to the particular weft being inserted, closes its circuit. VA is then divided between 10 and 12 to give an output VO, the value of which depends on VA and on the resistors 10 and 12; whereby, whichever the weft yarn in movement, the output VO is the same (in one practical embodiment, to which reference will be made hereinafter, this will be 1 volt). If, instead, at a certain moment one of the wefts breaks, all the electronic switches 17 to 24 remain open and VO thus becomes equal to zero. It can however happen that two weft yarns are inserted simultaneously by mistake. In this case, two of the electronic switches 17 to 24 close simultaneously. Under these conditions, VA is divided between two parallel resistors 10 on one side and the resistor 12 on the other, and the voltage VO increases with respect to its normal value (and becomes for example 2 volts). In conclusion, if the loom operates by inserting the wefts individually, a signal is supplied by the network 3 to the blocks 5, 6, which, in the example given, is of 1 volt if loom operation is normal, of 0 volt if a weft breaks, and of 2 volts if there is double weft insertion.
A second case is that in which the loom operates on complete double weft insertion. In this case, for the programming, the switch 16 of the network 3 is closed, so as to cause two parallel resistors 10, 10, on one side of the voltage divider (always connected for the normal simultaneous operation of two of the switches 17 to 24) to correspond to two resistors 12, 13 on the other side. If loom operation is regular, and the wefts are inserted in pairs as scheduled, the voltage VA is divided, as in the previous case, between the pairs of resistors, whereby VO is always the same (and is thus again of 1 volt, referring to the previous example). If, instead, one of the two weft threads to be simultaneously inserted breaks, the network is thrown out of balance by the opening of one of the switches 17 to 24 and by the exclusion of the corresponding resistor 10. The voltage VO halves (and will thus be 0.5 volt, in the example). If on the contrary, there is simultaneous insertion of more than two wefts, the network 3 is thrown out of balance in the opposite direction to the previous one (and VO will thus be equal to 1.5 volts, in the case of the example given). Breakage of both weft yarns to be inserted could also occur, in which case VO would be equal to zero.
The device is also adapted to intervene in a third case, namely when weaving with some double weft yarn insertions and some single weft yarn insertions. In this case the control must be selective. The network represents the case in which the electronic switches 17 and 18 control two single wefts, and the switches 19 to 24 (six in all) control three double wefts, each weft yarn being evidently controlled by one transducer 1 (FIG. 1). In this case, to program the network 3, the switches 14, 15 and 16 are closed. If loom operation is regular, upon insertion of the double wefts, two of the switches 19 to 24 close and the voltage VA divides between pairs of resistors 10 and pairs of resistors 12, 13 (whereby in the given example, VO equals to 1 volt). Likewise, upon insertion of the single wefts, the switch 17 or 18 closes and the voltage VA divides, as above, between the resistors 10, 11 and the resistors 12, 13 (VO = 1 volt). If one of the single wefts, or both the yarns of one of the double wefts break, the switches 17 to 24 are all opened and VO equals to 0. If, instead, one of the yarns of the double wefts breaks, only one of the switches 19 to 24 closes; the voltage divides between one resistors 10 on one side and the pair of resistors 12, 13 on the other, and the network 3 is thrown out of balance (VO = 0.5 volt, in the example). If a double weft is inserted instead of a single weft, the switches 17 and 18 close simultaneously and the voltage VA is divided between two pairs of resistors 10, 11 and one pair of resistors 12, 13 respectively; the network 3 is thrown out of balance (and the voltage VO = 2 volts, in the example given). Finally, two pairs of double weft yarns may be inserted simultaneously, or one pair of double weft yarns and one single weft yarn. In this case, either two pairs of switches 19 to 24 or one of the switches 17, 18 and one pair of the switches 19 to 24 are closed. Under these conditions, the network 3 is thrown out of balance as previously (VO = 2 volts, as above).
By comparing the values of VO, obtained in the various situations in the wide set of examples examined, it can be seen that there is always a certain value of VO corresponding to normal loom operation (VO = 1 volt in the chosen example), a value of VO below the normal value (0.5 volt, for example) or equal to zero, in the case of breakage of one or more weft yarns, and a value of VO above the normal value (VO = 1.5 or VO = 2 volts, in the example) in the case of too many wefts being inserted.
In view of this, it is quite easy to follow the operation of that part of the device downstream of the network 3. When the output signal from the network 3 is that corresponding to normal operation (VO = 1 volt) neither the block 5, which is adapted to emit signals when receiving signals of smaller voltage, nor the block 6, which is adapted to emit signals when receiving signals at higher voltages, operate. When the output signal from the network 3 is less than the normal value (VO = 0.5 volt or VO = 0) the block 4 comes into operation; this, however, has to give an output signal only when the loom gripper has almost completely traversed the entire length of the warp, since the checking on the integrity of the weft yarns should evidently be made only during this particular stage on the loom movement (in this respect, there is normally one stage in the cycle in which the wefts are at rest, and if the control device were activated at this time, the loom would be stopped without reason). This is obtained by means of the gate device 4 which is controlled by a cam which is integral with the loom movement. When the block 4 gives its gate signal, the block 5 operates the block 7, which stops the loom and lights an indicator lamp with a continuous light (broken yarn). If, however, the output signal from the network 3 is higher than the normal value (VO = 1.5 or VO = 2 volts), the block 6 comes into operation. In this case, no gate signal is required, since normally, the voltage level cannot be higher than the normal value at any stage in the cycle (wefts at rest or wefts in movement).
The block 6 operates in turn, again through the block 7, the stopping of the loom and the intermittent lighting of the indicator lamp (double insertion).
In this manner, while the loom stops each time there is an irregularity in operation, the operator has an immediate indication of the type of irregularity which has occurred and may rapidly restore the loom to working condition.
Because of the possibility to program the operation of the device described, by simply operating the switches in the logic network, it is evident that said device has a latitude of intervention which is exceptionally wide, or even complete, in that none of the irregularities which may occur in feeding the weft yarns to any type of loom and in any type of weaving operation, can escape its control.
The result is evidently of utmost importance and represents a great improvement over any known device of this type. The practical construction of the device obviously requires particular care. From experiments made so far it has been found, for example, that the transducers must be able to detect also the movement of fine, smooth and regular yarns producing only a very small or negligible tension on the yarn, and this because in gripper looms, the weft yarn must have maximum freedom of movement and must therefore not undergo any external stress. On the other hand, the transducers must also provide a high signal/disturbance ratio, which is not objectively simple in machines such as looms which are subject to very strong vibrations and noise.
There must further be high mechanical insulation to vibrations between one transducer and another, so that the vibrations induced into one transducer, by the movement over it of a yarn with large irregularities, are not transmitted to the adjacent transducers, and a proper choice of time constants must be made in order to obtain a certain lag in the control of the electronic switches in relation to yarn breakage (about 4 to 6 milliseconds).
In the practical embodiment of the device, the possibility has been tried of locating the blocks 1, 2 and 3 of the device in a single small-size container. The unit thus constructed may be electrically connected to the main panel of the loom by only three wires, with obvious simplicity of application.
The figures of the drawings and the description given heretofore refer only to one embodiment of the invention, given by way of non-limiting example. Other embodiments and various modifications of the one illustrated are however possible, as will be evident to those skilled in the art, without thereby departing from the scope of the present invention.
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Electronic device for controlling weft yarn insertion in continuous weft feed looms, without shuttles, adapted to stop the loom and emit a corresponding signal, not only each time there is a breakage or absence of a weft yarn, but also whenever the undesired insertion of double wefts occurs. This device comprises a plurality of transducers, each activated by a weft yarn, a logic network and means for stopping the loom, said logic network comprising means for storing a predetermined law of insertion of the individual weft yarns corresponding to a certain weaving operation on the loom, and for comparing with said law the actual weft insertions detected by the transducers.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates to steam irons and more particularly to steam iron with controlled water flow and steam generation.
[0002] Steam irons are well known and have been in use for many years. Such irons have a handle and a base. The base includes a water reservoir, a steam chamber in fluid communication with the water reservoir, a heating element, and a base plate having a number of steam spray ports therein. Typically, the heating element heats water in the steam chamber to generate steam that may be expelled from the base plates via the steam spray ports in response to the user pressing a button. Thus, the amount of steam released from the iron depends in large part on the user. If the user presses the button for a prolonged period of time, all of the steam will be expelled from the steam chamber.
[0003] It would be advantageous to have a steam iron that can automatically control the generation and flow of steam.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] The following detailed description of preferred embodiments of the invention will be better understood when read in conjunction with the appended drawings. The present invention is illustrated by way of example and is not limited by the accompanying figures, in which like references indicate similar elements. It is to be understood that the drawings are not to scale and have been simplified for ease of understanding the invention.
[0005] FIG. 1 is a side, cross-sectional view of a steam iron in accordance with one embodiment of the invention; and
[0006] FIGS. 2A-2D illustrate the operation of a steam iron in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0007] The detailed description set forth below in connection with the appended drawings is intended as a description of a presently preferred embodiment of the invention, and is not intended to represent the only form in which the present invention may be practiced. It is to be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the invention. In the drawings, like numerals are used to indicate like elements throughout.
[0008] In one embodiment, the present invention provides a steam iron including a heatable base plate having a plurality of steam outlets. A reservoir is provided for holding water and steam. A heating element is located near to the base plate and the reservoir for heating the base plate and for heating water in the reservoir and converting the water to steam. At least one steam pipe connects the base plate steam outlets with the reservoir that allows steam to move from the reservoir to the steam outlets and exit the iron. A first valve is located along the steam pipe between the reservoir and the steam outlets for regulating the flow of steam through the steam pipe. Steam may move from the reservoir to the steam outlets when the first valve is in an open position. A first actuator moves the first valve between the open position and a closed position. A sensor, coupled to the actuator, detects and measures a speed of movement of the steam iron. The actuator moves the first valve between the open and closed positions depending on the detected speed of movement.
[0009] In another embodiment, the sensor is three axis accelerometer that detects both speed and tilt angle of the steam iron and the actuator is a microcontroller that moves the valve between the open and closed positions depending on either or both of the speed of movement and the tilt angle of the steam iron. When the steam iron is moved at a predetermined speed and at a predetermined angle, steam is automatically expelled via the steam outlets.
[0010] A steam iron 10 in accordance with various embodiments of the present invention now will be described with reference to FIG. 1 . The steam iron 10 has a heatable base plate 12 having a plurality of steam spray ports or outlets 14 therein. A reservoir is provided for holding water and steam. In one embodiment of the invention, the reservoir comprises a water reservoir 16 for holding water and a steam chamber 18 for holding steam. The water reservoir 16 is in fluid communication with the steam chamber 18 . The base plate 12 , steam outlets 14 , water reservoir 16 and steam chamber 18 are all well known elements of a steam iron to those of skill in the art and a detailed description is not required for a complete understanding of the invention. Further, although the water reservoir 16 and steam chamber 18 are shown as in the drawing as separate elements at particular locations and of particular size and shape, in fact, these elements may comprise various numbers, sizes, shapes and locations, and the present invention should not be limited by such features of these elements.
[0011] The iron 10 includes a heating element for heating water in the water reservoir 16 and converting the water to steam, and heating the base plate 12 . In one embodiment of the invention, the heating element comprises at least two heating elements. A first heating element 20 is located proximate to or integral with the base plate 12 for heating the base plate 12 . A second heating element 22 is located proximate to or integral with the steam chamber 18 for converting water in the steam chamber to steam. In another embodiment of the present invention, a pre-heating element 24 is located proximate to or integral with the water reservoir 16 for pre-heating the water stored in the water reservoir 16 . Although the heating elements 20 , 22 and 24 are shown as adjacent to the base plate 12 , steam chamber 18 and water reservoir 16 , respectively, it will be understood by those of skill in the art that the heating elements may comprise various types of heating elements and be located at several different positions, such as adjacent to, near to, or integral with the base plate 12 , water reservoir 16 , and steam chamber 18 , respectively. Thus, the present invention should not be limited by the type, number, or location of the heating elements.
[0012] At least one steam pipe 26 connects the base plate steam outlets 14 with the steam chamber 18 and allows steam in the steam chamber 18 to move to the steam outlets 14 and exit or be sprayed from the iron 10 . A first valve 28 is located along the steam pipe 26 between the steam chamber 18 and the steam outlets 14 for regulating the flow of steam through the steam pipe 26 . When the first valve 28 is in an open position, steam may move from the steam chamber 18 to the steam outlets 14 , and when the first valve 28 is in a closed position, steam may not traverse the steam pipe 26 . Although only one steam pipe 26 and first valve 28 are shown, the steam iron 10 may have more than one steam pipe 26 that connects the steam chamber 18 with the steam outlets 14 .
[0013] In one embodiment of the invention, the steam iron 10 also includes a water pipe 30 connecting the water reservoir 16 with the steam chamber 18 . A second valve 32 is located along the water pipe 30 for regulating the flow of liquid between the water reservoir 16 and the steam chamber 18 . When the second valve 32 is in an open position, liquid stored in the water reservoir 16 may move to steam chamber 18 , and when the second valve 32 is in a closed position, liquid may not traverse the water pipe 30 . Although only one water pipe 30 and second valve 32 are shown, the steam iron 10 may have more than one water pipe 30 that connects the water reservoir 16 with the steam chamber 18 .
[0014] In one embodiment of the invention, the steam iron 10 includes first and second actuators for moving the first and second valves 28 and 32 , respectively, between their respective open and closed positions. In one embodiment of the invention, the first and second actuators comprise a microcontroller 34 that is electrically connected to the first and second valves 28 and 32 , and sends respective first and second actuator signals 36 and 38 to the first and second valves 28 and 32 to move the first and second valves 28 , 32 between their open and closed positions.
[0015] A sensor 40 is coupled to the microcontroller 34 for detecting and measuring a speed of movement of the steam iron 10 . The sensor 10 sends the measured speed data to the microcontroller 34 and the microcontroller 34 generates the first actuator signal 36 , to move the first valve 38 between the open and closed positions, depending on the detected speed of movement. In one embodiment of the present invention, the sensor 40 comprises an accelerometer, such as a 3-axis accelerometer that can measure both speed and tilt angle of the steam iron 10 . In such embodiment, the microcontroller 24 receives the measured speed and tilt data from the sensor 40 and generates the first and second actuator signals 36 , 38 , for moving the first and second valves 28 , 32 between their open and closed positions. The generation of steam and the flow of liquid between the water reservoir 16 , the steam chamber 18 and the base plate steam outlets 14 are thus controlled.
[0016] The sensor 40 may comprise a Micro-electromechanical system (MEMS) sensor. MEMS dual axis accelerometers are presently available in small packages, on the order of 4 mm×4 mm×1.5 mm. Such devices operate on power supplies around 3 v and provide signal conditioned voltage outputs for a variety of motion sensing, tilt sensing and inertial sensing features. For example, small tilt changes can be sensed using narrow bandwidths. Example MEMS sensors that may be used to realize the present invention are Freescale Semiconductor, Inc.'s MMA7455L and MMA7456L accelerometers, which can be used for sophisticated portable electronics products.
[0017] The speed and tilt data provided by the sensor 40 to the microcontroller 34 are used as further described herein. In one embodiment, when the iron 10 moves faster than a first predetermined speed, the controller 34 generates the first actuator signal 36 to move the first valve 28 from its closed position to its open position. This would be the case for when the iron 10 is in a steam mode and a user is moving the iron 10 back and forth over an item to be ironed. The sensor 40 detects the movement speed of the iron 10 and sprays steam stored in the steam chamber 18 by way of the steam outlets 14 by causing the first valve 28 to be opened. Conversely, when the iron 10 moves slower than the first predetermined speed, the first valve 28 is moved from the open position to the closed position.
[0018] As discussed above, in addition to measuring speed of movement, the sensor 40 can also detect and measure tilt angles. Such tilt angle data is provided from the sensor 40 to the controller 34 . In turn, the controller 34 causes the first valve 28 to move between the open and closed positions depending on the detected tilt angle. In one embodiment of the invention, the first valve 28 is closed when a tilt angle of the steam iron 10 is about 90° (e.g., 90°±10°). That is, the user has placed the iron 10 in an upright or erect position, such as that shown in FIG. 2A . In another embodiment of the invention, the first valve 28 is closed when a tilt angle of the steam iron 10 is greater than about 20° (e.g., 20°±10°), as shown in FIG. 2D .
[0019] Referring now to FIGS. 2A-2D , the operation of the steam iron 10 is shown. FIG. 2A shows the steam iron 10 in an upright or erect position. The iron 10 would be in such position, for example, before or after use, or when the user is taking a break or re-positioning the item being ironed. When the iron 10 is in the upright position (i.e., the tilt angle is about 90°, as detected by the sensor 40 ), the first valve 28 is maintained in the closed position.
[0020] FIGS. 2B and 2C show the iron 10 in a flat or in-use position (i.e., the tilt angle is close to 0°, as detected by the sensor 40 ). In such case, the sensor 40 also measures the speed at which the iron is being moved, either forward or backward, and can cause steam to be sprayed out of the steam outlets 14 . That is, the tilt angle and speed data are provided from the sensor 40 to the controller 34 and the controller 34 causes the first valve 28 to be opened (or closed as the case may be).
[0021] FIG. 2D shows the steam iron 10 being lifted or moved from a relatively flat, in-use position, to an upright position. When the iron 10 is at an angle of greater than about 10°, the controller 34 causes the first valve 28 to be closed.
[0022] The iron 10 may include additional features. For example, temperature information may be passed from the heating elements 20 , 22 and 24 to the controller 34 so that optimal temperatures thereof may be maintained. Temperature sensors and their interconnection to a microcontroller are well understood by those of skill in the art. In addition, water and steam level information may be passed to the microcontroller 34 so that liquid may be moved from the water reservoir 16 to the steam chamber 18 whenever the steam chamber 18 is low on steam or needs additional steam to maintain enough pressure to eject steam out the steam ports 14 .
[0023] As is evident from the foregoing discussion, the present invention provides a steam iron with improved steam flow control. By incorporating a three-axis accelerometer, both motion and tilt angle information can be detected and provided to a controller that regulates the production and flow of steam. For example, when the iron is moved from an upright position to an in-use position, steam production may be commenced and when the iron is moved from the in-use position to the upright position, steam production may be inhibited. Additionally, steam generation and ejection can be based on the speed and direction of movement of the iron when in the in-use position. As will be understood by those of skill in the art, the first and second valves 28 and 32 may be opened and/or closed based on other factors not discussed herein, yet not required for a complete understanding of the present invention.
[0024] The description of the preferred embodiments of the present invention have been presented for purposes of illustration and description, but are not intended to be exhaustive or to limit the invention to the forms disclosed. It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but covers modifications within the spirit and scope of the present invention as defined by the appended claims.
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A steam iron includes a sensor for detecting and measuring movement of the steam iron. The sensor is coupled to an actuator that regulates the flow of steam via a valve located between a steam chamber and steam outlets. The sensor can detect movement in three directions (X, Y, Z) and adjust steam generation based on speed of movement of the iron and tilt angle. A pre-heater is used to pre-heat water in a water chamber. The pre-heated water is provided to a steam chamber where it is later converted to steam.
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This application claims benefit of USC Provisional appln. Ser. No. 60/020,666, filed Jun. 28, 1996.
BACKGROUND OF THE INVENTION
The present invention relates to compositions having enhanced or improved bioavailability for a novel triazole antifungal compound.
International Patent Publication Number WO 95/17407 published 29 Jun. 1995, teaches a novel class of tetrahydrofuran/triazole antifungal compounds. One particular compound, (2R-cis)-4- 4- 4- 4- -5-(2,4-difluorophenyl)tetrahydro-5-(1H-1,2,4-triazol-1-ylmethyl)furan-3-yl!methoxy!phenyl!-1-piperazinyl!phenyl!2-4-dihydro-2- (S)-1-ethyl-2(S)-hydroxypropyl!-3H-1,2,4-Triazol-3-One ("the antifungal compound"), was found to have potent antifungal activity in suspensions against opportunistic fungi such as Aspergillis, Candida, Cryptococcus and other opportunistic fungi. However, solid compositions, such as powders or granules, were found to have reduced anti-fungal activity and/or bioavailability, presumably due to this compound's extremely low water solubility. It would be desirable to provide this antifungal compound in a pharmaceutical composition whose antifungal and/or bioavailabilty would be enhanced or improved.
SUMMARY OF THE INVENTION
The present invention is directed to a pharmaceutical composition comprising:
i) a plurality of beads; wherein said beads are coated with
ii) an antifungal agent of the formula: ##STR1## iii) a binder to enables the antifungal compound to adhere to said beads.
The pharmaceutical composition may also contain other excipients such as iv) surfactants, v) plasticizers, vi) defoaming agents and coloring agents. The pharmaceutical composition can also be formulated into any other suitable delivery system or dosage form, such as capsules, tablets, or beads for reconstitution.
It has also been surprisingly and unexpectedly found that the coating of beads with the antifungal compound using a suitable binder, can enhance or be equivalent to the bioavailability of the antifungal compound compared to suspensions. These results are truly surprising and unexpected, since known references, such as Peter G. Welling, Pharmacokinetics, Processes and Mathematics, American Chemical Society, Washington D.C., ACS Monograph 185, 1986, page 57, teaches that solutions and suspensions generally give rise to more satisfactory bioavailability than capsules or tablets. J. G. Nairn, Remington's Pharmaceutical Sciences, 18th Edition, 1990, Mack Publishing Co., Chapter 83, page 1519 also teaches that since drugs are absorbed in their dissolved state, frequently it is found that the absorption rate of oral dosage forms decreases in the following order: aqueous solution>aqueous suspension>capsule or tablet.
The present invention has the advantage of being able to provide the antifungal compound in a pharmaceutical composition that can conveniently be formulated into solid or "dry" delivery systems or dosage forms such as capsules, tablets or loose beads having effective antifungal activity and/or bioavailabilty.
DETAILED DESCRIPTION OF THE EMBODIMENTS
WO 95/17407 published 29 Jun. 1995 discloses antifungal compounds of the formula: ##STR2## wherein R 1 is a straight or branch chain (C3 to C8) alkyl group substituted by one or two hydroxy moieties; esters and ethers thereof or a pharmaceutically acceptable salt thereof. An especially preferred compound of the above group taught in Examples 24 and 32 of WO 95/17407 is the antifungal compound, (-)-(2R-cis)-4- 4- 4- 4- -5-(2,4-difluorophenyl)-tetrahydro-5-(1H-1,2,4-triazol-1-ylmethyl)furan-3-yl!methoxy!phenyl!-1-piperazinyl!phenyl!-2,-4-dihydro-2- (S)-1-ethyl-2(S)-hydroxypropyl!-3H-1,2,4-triazol-3-one ("the antifungal compound"); Formula: C 37 H 42 F 2 N 8 O 4 ; Molecular weight: 700.8; m.p. 164°-165° C., a! D 25 -29° C.±3° (c=1.0, CHCl 3 ), whose structure is depicted below: ##STR3##
Micron-sized particles of the antifungal compound can be obtained either by the final step during the manufacture of the antifungal compound or by the use of conventional micronizing techniques after the conventional crystallization procedure(s).
Where micronizing techniques are employed, the antifungal compound may be micronized to the desired particle size range by conventional techniques, for example, using a ball mill, ultrasonic means, or preferably using fluid energy attrition mills such as the trost fluid energy mill from Plastomer Products, Newton, Pa. 18940. When using a fluid energy attrition mill, the desired particle size can be obtained by varying the feed rate of the antifungal into the mill.
About 99% of the of the micronized antifungal particle are less than or equal to 100 microns in length, of which 95% are less than or equal to 90 microns. Preferably, about 99% of the micronized particles are less than or equal to 50 microns, of which 95% are less than or equal to 40 microns. More preferably, 99% of the micronized particles are less than or equal to 20 microns, of which 95% are less than or equal to 10 microns.
The antifungal compound is employed in the composition in amounts effective to control the organism or fungi of interest. Such amounts can range from about 2% to about 50% by weight of the composition, more preferably from 6% to about 40%, most preferably from about 5 to about 33% by weight. The amount of composition in the particular dosage form, e.g. capsule, tablet, etc., can range from about 10 to about 300 mg antifungal compound per dosage form, preferably from about 50 to about 200 mg.
Compositions of the present invention can be prepared by dissolving or suspending the antifungal compound in an a suitable solvent system containing a binder, and optionally with one or more ingredients such as a surfactant, plasticizer, defoaming agent and/or coloring agent and coating the solution or suspension on the inert beads.
The pharmaceutical composition of the present invention can be formulated into any suitable dosage form, such as capsules, tablets or loose beads for constitution. For example, the above composition can be compressed into tablet form using a suitable cushioning agent, such as microcrystalline cellulose, and optionally, a disintegrant, lubricant, glident, and the like.
The following terms are used to describe the present pharmaceutical compositions, ingredients which can be employed in its formulation and methods for assessing its bioactivity or bioavailability.
The beads or seeds are discrete particles, preferably spherical particles or spheres, which serve as the solid substrate upon which the antifungal compound is coated, and make up the major portion of the composition or dosage form. Beads can be made of sugars such as lactose, sucrose, mannitol and sorbitol; other beads can be derived from starches derived from wheat, corn rice and potato; and celluloses such as microcrystalline cellulose. A source of sugar beads (non-pareil seeds) is known as Nu-pareil PG, tradename of Crompton and Knowles Ingredient Technology Corporation, of Mahawah, N.J. A source of microcrystalline cellulose beads is known as Celphere, tradename of the FMC Corporation, Philadelphia, Pa. Beads of differing mesh sizes can be employed, such as 18/20 mesh, 25/30 mesh and 40/50 mesh. Such mesh sizes refer to particle or bead sizes whose diameters can ranges from about 1.0 millimeters (mm) to about 0.297 mm. Preferably the bead sizes or diameters are within a relative narrow range such as, for example, between about 1.0-0.84 mm (18/20 mesh), or between about 0.71-0.59 mm (25/30 mesh), or between about 0.42-0.297 mm (40/50 mesh). The beads should be "inert" meaning that the beads themselves have little or no antifungal effectiveness. The amount of beads in the composition can range from about 50 to about 90% by weight of the total composition, preferably from about 60 to about 80%, more preferably from about 65 to about 75% by weight.
Binders--refers to substances that bind or "glue" the antifungal compound and other ingredients onto the beads, enabling the beads to be coated. Suitable binders include sugars such as sucrose; starches derived from wheat, corn rice and potato; natural gums such as acacia, gelatin and tragacanth; derivatives of seaweed such as alginic acid, sodium alginate and ammonium calcium alginate; cellulosic materials such as methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose and sodium carboxymethylcellulose; polyvinylpyrrolidone (Povidones); protein hydrolysates; methacrylic acid and salts thereof; and inorganic compounds such as magnesium aluminum silicate. A commercially available formulation useful as a binder is known as Opadry powders, tradename of the Coloron Corporation, West Point, Pa. Opadry powders may contain hydroxypropylmethylcellulose, along with a plasticizer such as polyethylene glycol and a surfactant such as polysorbate-80. The amount of binder in the composition can range from about 1 to about 10% by weight of the composition, preferably from about 2 to about 8% by weight, more preferably from about 3 to about 6%.
Disintegrants--refers to materials added to the composition to help it break apart (disintegrate) and release the medicaments. Suitable disintegrants include starches; "cold water soluble" modified starches such as sodium carboxymethyl starch; natural and synthetic gums such as locust bean, karaya, guar, tragacanth and agar; cellulose derivatives such as methylcellulose and sodium carboxymethylcellulose; microcrystalline celluloses and cross-linked microcrystalline celluloses such as sodium croscarmellose; alginates such as alginic acid and sodium alginate; clays such as bentonites; and effervescent mixtures. The amount of disintegrant in the composition can range from about 2 to about 15% by weight of the composition, more preferably from about 4 to about 10% by weight.
Surfactant--refers to a compound that can reduce the interfacial tension between two immiscible phases and this is due to the molecule containing two localized regions, one being hydrophilic in nature and the other hydrophobic.
Non-ionic surfactant--refers to a surfactant which lacks a net ionic charge and do not dissociate to an appreciable extent in aqueous media. The properties of non-ionic surfactants are largely dependent upon the proportions of the hydrophilic and hydrophobic groups in the molecule. Hydrophilic groups include the oxyethylene group (--OCH 2 CH 2 --) and the hydroxy group. By varying the number of these groups in a hydrophobic molecule, such as a fatty acid, substances are obtained which range from strongly hydrophobic and water insoluble compounds, such as glyceryl monostearate, to strongly hydrophilic and water-soluble compounds, such as the macrogols. Between these two extremes types include those in which the proportions of the hydrophilic and hydrophobic groups are more evenly balanced, such as the macrogol esters and ethers and sorbitan derivatives. Suitable non-ionic surfactants may be found in Martindale, The Extra Pharmacopoeia, 28th Edition, 1982, The Pharmaceutical Press, London, Great Britain, pp. 370 to 379. Such non-ionic surfactants include block copolymers of ethylene oxide and propylene oxide, glycol and glyceryl esters of fatty acids and their derivatives, polyoxyethylene esters of fatty acids (macrogol esters), polyoxyethylene ethers of fatty acids and their derivatives (macrogol ethers), polyvinyl alcohols, and sorbitan esters. Preferably, the non-ionic surfactant is a block copolymer of ethylene oxide and propylene oxide.
Suitable block copolymers of ethylene oxide and propylene oxide generically called "Poloxamers" and include those represented by the following chemical structure: ##STR4## wherein a is an integer ranging from about 10 to about 110, preferably from about 12 to 101; more preferably from about 12 to 80; and
b is an integer ranging from about 20 to about 60, more preferably from about 20 to about 56; also from about 20 to 27. Most preferably, a is 80 and b is 27, otherwise known as Pluronic®F68 surfactant, trademark of the BASF Corporation, Mount Olive, N.J., USA. Pluronic®F68 surfactant is also known as Poloxamer 188. This surfactant has an average molecular weight of 8400, is a solid at 20° C., has a viscosity (Brookfield) of 1000 cps at 77° C. Other suitable block copolymers of ethylene oxide and propylene oxide include Pluronic F87, also known as Poloxamer 237 wherein a is 64 and b is 37; and Pluronic F127, also known as Poloxamer 407 wherein a is 101 and b is 56.
Suitable glycol and glyceryl esters of fatty acids and their derivatives include glyceryl monooleate and similar water soluble derivatives;
Suitable polyoxyethylene esters of fatty acids (macrogol esters) include polyoxyethylene castor oil and hydrogenated castor oil derivatives;
Suitable polyoxyethylene ethers of fatty acids and their derivatives (macrogol ethers) include Cetomacrogel 1000, Lauromacrogols (a series of lauryl ethers of macrogols of differing chain lengths) e.g. Laureth 4, Laureth 9 and Lauromacrogol 400.
Suitable Sorbitan esters (esters of one or more of the hydroxyl groups in the sorbitans, with a fatty acid, such as stearic, palmitic, oleic or lauric acid) include, e.g. Polysorbate 20, Polysorbate 40, Polysorbate 60, Polysorbate 65, Polysorbate 80, Polysorbate 85, Sorbitan Monolaurate, Sorbitan Mono-oleate, Sorbitan Monopalmitate, Sorbitan Monostearate, Sorbitan Sesquioleate, Sorbitan Trioleate and Sorbitan Tristearate.
The amount of surfactant in the composition can range from about 0.5 to about 25% by weight of the total composition, more preferably from about 5 to about 15% by weight.
Anionic surfactant--refers to a surfactant which has a net negative ionic charge and dissociates to an appreciable extent in aqueous media. Optionally, the present composition may also contain an anionic surfactant, e.g. sodium lauryl sulfate, the amount of which can range from about 1 to about 10% by weight of the total composition, more preferably from about 3 to about 8% by weight.
Plasticizers--refers to substances which make the binder flexible. Suitable plasticizers include propylene glycol, glycerin, diethylphthalate, dibutyl sebacate, triethyl citrate, hydrogenated glycerides, polyethylene glycols, polyethylene oxides, triacetin and the like. The amount of plasticizer in the composition can be in the range of about 1-2 to about 5% by weight.
Defoaming agents, also known as antifoaming agents, are substances used to reduce foaming due to mechanical agitation or to gases, nitrogenous materials or other substances which may interfere during processing. Examples include metallic salts such as sodium chloride; C6 to C12 alcohols such as octanol; sulfonated oils; silicone ethers such as simethicone; organic phosphates and the like. The amount of defoaming agent in the composition can range from about 0.05 to 5%, preferably from about 0.1 to 2%.
Glidents--materials that prevent caking and improve the flow characteristics of granulations, so that flow is smooth and unifom. Suitable glidents include silicon dioxide and talc. The amount of glident in the composition can range from about 0.1% to about 5% by weight of the total composition, preferably from about 0.5 to about 2% by weight.
Lubricant--refers to a substance added to the dosage form to enable the tablet, granules, etc. after it has been compressed, to release from the mold or die by reducing friction or wear. Suitable lubricants include metallic stearates such as magnesium, calcium or potassium stearate; stearic acid; high melting point waxes; and water soluble lubricants such as sodium chloride, sodium benzoate, sodium acetate, sodium oleate, polyethylene glycols and d'l-leucine. Lubricants are usually added at the very last step before compression, since they must be present on the surfaces of the granules and in between them and the parts of the tablet press. The amount of lubricant in the composition can range from about 0.2 to about 5% by weight of the composition, preferably from about 0.5 to about 2%.
Coloring agents--excipients that provide coloration to the composition or the dosage form. Such excipients can include food grade dyes and food grade dyes adsorbed onto a suitable adsorbent such as clay or aluminum oxide. The amount of the coloring agent can vary from about 0.1 to about 5% by weight of the composition, preferably from about 0.1 to about 1%.
Dosage form--composition containing the antifungal compound formulated into a delivery system, i.e., tablet, capsule, oral gel, powder for constitution or suspension in association with inactive ingredients.
Capsule--refers to a special container or enclosure made of methyl cellulose, polyvinyl alcohols, or denatured gelatins or starch for holding or containing compositions comprising the active antifungal compound. Hard shell capsules are typically made of blends of relatively high gel strength bone and pork skin gelatins. The capsule itself may contain small amounts of dyes, opaquing agents, plasticizers and preservatives.
Tablet--refers to a compressed or molded solid dosage form containing the active ingredient (antifungal compound) with suitable diluents. The tablet can be prepared by compression of mixtures or granulations obtained by wet granulation, dry granulation, compaction or compression of mixtures containing coated active beads.
Beads for constitution refers to the loose, coated beads which can be suspended in water, juices or sauces such as applesauce.
Bioavailability--refers to the rate and extent to which the active drug ingredient or theraputic moiety is absorbed into the systemic circulation from an administered dosage form as compared to a standard or control.
C max values refers to the maximum concentration of the antifungal compound measured (i.e. "peak") in the plasma serum.
AUC (0-72 hr) values refer to the area under the plasma/serum concentration-time curve for the antifungal over a designated time.
Conventional methods for preparing tablets are known. Such methods include dry methods such as direct compression and compression of granulation produced by compaction, or wet methods or other special procedures.
The following examples describe compositions of the present invention containing the antifungal compound, but they are not to be interpreted as limiting the scope of the claims.
______________________________________Example 1Coated Beads in CapsulesIngredient g/batch % wt basis______________________________________Antifungal compound, 135 20.3micronizedOpadry YS-1-7006 30 4.5Simethicone 1.42 0.2Water purified, USP 700 mL --(evaporates)Non-Pareil Seeds (25/30 mesh) 500 75 666.42 100%______________________________________
______________________________________Example 2Coated Beads in CapsulesIngredient mg/batch % wt basis______________________________________Antifungal compound, 75 11.0micronizedOpadry YS-1-7006 30 4.4Pluronic F68 surfactant 75 11.0Simethicone 0.7 0.1Water purified, USP 500 mL --(evaporates)Non-Pareil Seeds (25/30 mesh) 500 73.5 680.7 100%______________________________________
Preparation of Coated Beads in Capsules in Examples 1, 2 and 5
Dissolve the Opadry YS-1-7006, Pluronic F68 or sodium lauryl sulfate in water. Add simethicone while stirring. Add the antifungal compound while stirring slowly until a homogeneous suspension is formed. Screen the suspension through a 25 mesh hand screen. Spray the suspension onto the non-pareil seeds using a fluid bed coater. Dry the coated beads overnight and assay the coated beads to determine the amount of antifungal compound. Fill the coated beads into suitable size capsules to the requisite fill weight.
Preparation of Aqueous Suspension in Comparative Example 3
Prepare a suspension containing 59.8 mg Pluronic F68 in four mL of distilled water. Add 200 mg of antifungal compound to the above solution and mix to give a homogeneous suspension.
______________________________________Preparation of Powder Mixture in Capsules in Comparative Example 4Ingredient mg/capsule % wt basis______________________________________Antifungal compound, 100.0 28.6micronizedSodium lauryl sulfate surfactant 22.5 6.4Microcrystalline cellulose 178.0 50.9Sodium starch glycolate 45.0 12.8Magnesium stearate 4.5 1.3 350 100______________________________________
Mix the antifungal compound, sodium lauryl sulfate (a surfactant), microcrystalline cellulose, and sodium starch glycolate in a blender for 10 minutes. Add magnesium stearate and mix for 5 minutes to form a homogeneous powder. Fill the powder into suitable size capsules to the requisite fill weight.
Testing for Bioavailability
Dogs are administered a 200 mg dose of the antifungal compound using two capsules or in suspension. Samples of serum are collected at selected times and analyzed by an HPLC/UV detection procedure using a high pressure liquid chromatograph equipped with an ultra-violet detector. In the table below, the C max and AUC (0-72 hr) values are indicators of the antifungal compound's bioavailability. The larger the AUC value, the greater the total amount of antifungal compound that accumulated in the plasma serum over the 72 hour period.
______________________________________ Powder Coated Coated Control Mixture in Beads in Beads in Suspension- Capsules-Indicator of Capsules- Capsules- Comparative ComparativeBioavailabillity: Example 1 Example 2 Example 3 Example 4______________________________________C.sub.max (ug/ml) 1.43 1.37 1.21 0.95AUC.sub.(0-72 hr) 50.21 50.17 47.98 29.72ug/hr/ml______________________________________
The results above show that capsules of Examples 1 and 2 exhibit enhanced bioavailability over that of the aqueous suspension of Comparative Example 3 and especially over the powdered mixture in capsules of Comparative Example 4.
______________________________________Example 5Coated Beads in CapsulesIngredient g/batch % wt basis______________________________________Antifungal compound, 75.0 11.80micronizedOpadry YS-1-7006 30.0 4.72Sodium lauryl sulfate 30.0 4.72Simethicone 1.0 0.16Water purified, USP 500 mL --(evaporates)Non-Pareil Seeds (25/30 mesh) 500.0 78.60 636.0 100%______________________________________
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A pharmaceutical composition comprising:
i) substantially inert beads; wherein said beads are coated with
ii) an antifungal agent which is (-)-(2R-cis)-4- 4- 4- 4- -5-(2,4-difluorophenyl)tetrahydro-5-(1H-1,2,4-triazol-1-ylmethyl)furan-3-yl!methoxy!phenyl!-1-piperazinyl!phenyl!-2,4-dihydro-2- (S)-1-ethyl-2(S)-hydroxypropyl!-3H-1,2,4-triazol-3-one;
iii) a binder to enables the antifungal compound to adhere to said beads.
The composition enables the antifungal compound, which has very low water solubility, to have enhanced bioavailability in mammals, such as humans.
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BACKGROUND OF THE INVENTION
The invention concerns a customisation or initialisation method and device for portable communicating devices such as smart cards.
With the coming of open or closed programmable smart cards, it is possible to have said smart cards execute service applications, that is to say executable software programs, coming from various sources. To that end, a programmable card comprises rewritable memory areas for storing one or more applications according to its use, and a processor able to execute such applications.
These service applications, also known by the term “applets”, come in the form of complex programs, generally designed by means of high-level languages such as JavaCard, C++, Visual Basic, etc. Each service application comprises an “applications” part which provides the execution of the program in normal mode, and an “administrative” part which is used only at an initial stage for customising the application to the holder of the card. The stored data which constitute the software means of this administrative part are designated “administrative code”, or “customisation code”. This code can occupy up to several tenths of the whole of the code forming the application. Within the context of the invention, the term “customisation” also comprises any other similar process to be executed in an application, such as parameter initialisation.
The customisation code is used in particular for the loading into the card of data specific to the user, so that they can be read and used if necessary during normal execution of the application. Conventionally, the on-board customisation code in a smart card or other portable communicating device must provide the following functions:
dialogue according to an established protocol with a customisation program outside the card—a distinction is then made of the on-card customisation code, contained in the rewritable memory area, and the off-card customisation code, contained for example in a remote terminal or a server; recognition of instructions for identifying and loading fields of data intended to contain values specific to the customisation; and loading of these customisation values into corresponding registers in the memory area of the card.
FIG. 1 illustrates in a simplified manner a few steps in the conventional process for loading customisation data from the outside into respective storage fields of a programmable card, during customisation of an application of this card. In the example, the card is connected by a terminal to a server or remote terminal which fills in the fields by means of an off-card customisation code.
For each field in the card to be filled in, the off-card customisation code comprises a first instruction, intended for the on-card customisation program, which indicates the designated specific field. The on-card customisation code must recognise each of these instructions in order to select the designated field and act accordingly. This recognition necessitates a decoding instruction specific to each field, which must be stored with the on-card customisation code.
Next, the off-card customisation code transmits the personal data to be written into the previously designated field. Upon reception of these data, the on-card customisation code executes the instructions necessary for loading them into a designated register according to the preceding instruction.
Once the first field has been loaded in this way, the process is repeated in an identical manner for each of the other fields. Thus, in the example of FIG. 1 , n personal information elements are loaded into respective fields of the card, each being preceded by a specific instruction which must be identified by the on-card customisation code.
By way of example, the process for customising an application intended for a medical services tracking card may fill in the following fields: field 1 =surname, field 2 =forename, field 3 =social security number, field 4 =height, field 5 =weight, etc. Similarly, the process for customising another application, for example intended for a bank card, will fill in the following fields: field 1 =personal identification number (PIN), field 2 =maximum number of code input attempts, field 3 =authorised weekly debit limit, field 4 =bank code, field 5 =branch code, etc.
The instructions relating to each field must not only identify it, but also indicate the form of the data contained (number and type of characters, formatting, etc.).
As these information elements are specific to each application, it follows that each application stored in a card must have its specific customisation code. The space occupied by this on-card customisation code increases with the number of applications loaded, and can occupy in total several tenths of the memory area of the card dedicated to the applications.
To sum up, this conventional method suffers from the following drawbacks:
it adapts with difficulty to remote customisations, since the method generally requires an exchange of a large number of commands, which can be very difficult to provide on a slow network; and
the customisation commands must be coded in all the applications of the card, which occupies a large memory area in the card.
SUMMARY OF THE INVENTION
In view of the above, the invention proposes a novel approach to the problem of customising an application, in particular when said application is contained in a portable communicating device such as a smart card.
More particularly, the invention provides, according to a first aspect, a method of preparing customisation or initialisation data for transmission to a portable communicating device, for example a smart card, the data comprising a number of information elements, each assigned to a field used by the device,
characterised in that the preparation consists of creating a concatenation of the information elements in contiguous respective data blocks organised according to a convention recognised by the communicating device, with no explicit field designation.
Preferably, the data blocks are formatted according to a number of pre-established types, the number of bytes used for writing an information element into the block assigned to it being a function of the type of this block. A number of aforementioned types can be envisaged, including at least one fixed type consisting of a fixed number of bytes and a variable format consisting of a variable number of bytes, this number being specified in the block.
The data can be transmitted in encrypted form.
According to a second aspect, the invention concerns a method for customising or initialising an application in a portable communicating device, for example a smart card, the customisation/initialisation comprising the reception of data coming from an external source in order to extract, from these data, information elements to be written into respective fields,
characterised in that it consists of accepting as an input said data in the form of a concatenation in which said information elements are defined by contiguous respective blocks, organised according to a convention recognised by said external source and said communicating device, with no explicit field designation, each received information element of said concatenation being identified according to the type and position of its data block in said concatenation.
Advantageously, each information element is extracted by reference to the type of data block in which it is contained, the type of each block for each field being established by the convention. Preferably, each information element extracted from the concatenation is transferred into a portion of storage for the corresponding field in the communicating portable device.
In the embodiments envisaged, the method comprises the filling in of each field with the corresponding value in a corresponding address of the communicating portable device, by the steps of:
storing, at an initial stage, said convention in order to know the order of appearance of the fields in said concatenation and the type of block in which the corresponding value is contained; storing the concatenation;
and for each filling in of a field:
sending a command for extracting the value by designation of the type of the data block in which it is contained, the extraction being carried out from the first byte, or from the byte following the last byte extracted previously, of said concatenation; and transferring said extracted value to a portion of memory of the portable device assigned to the corresponding field.
According to a third aspect, the invention concerns the implementation of the method according to the second aspect in a smart card.
According to a fourth aspect, the invention concerns a device for preparing customisation or initialisation data for transmission to a portable communicating device, for example a smart card, the data comprising a number of information elements, each assigned to a field used by said device,
characterised in that it comprises means for creating a concatenation of said information elements in contiguous respective blocks organised according to a convention recognised by said communicating device, with no explicit field designation.
According to a fifth aspect, the invention concerns a device for customising or initialising an application in a portable communicating device, for example a smart card, the customisation/initialisation comprising the reception of data coming from an external source in order to extract, from these data, information elements to be written into respective fields,
characterised in that it comprises means for accepting, as an input, the data in the form of a concatenation in which said information elements are defined by contiguous respective data blocks, organised according to a convention recognised by said external source and said communicating device, with no explicit field designation, and
means for identifying and extracting each received information element of said concatenation according to the type and position of its corresponding data block in said concatenation.
According to a sixth aspect, the invention concerns a communicating device, characterised in that it incorporates the device according to the fifth aspect.
This communicating device can more specifically be a smart card.
The optional characteristics of the invention, presented within the context of the method according to the first three aspects, apply mutatis mutandis to the device and system according to the last four aspects.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention and the advantages which ensue therefrom will emerge more clearly from a reading of the following description of preferred embodiments, given purely by way of non-limiting examples with reference to the accompanying drawings, in which:
FIG. 1 , already described, depicts some of the instructions transmitted to a smart card during customisation of an application, in particular for filling in personal data fields;
FIG. 2 is a simplified block diagram of the main elements of an “open” programmable smart card;
FIG. 3 is an explanatory diagram showing how personal data in a databank file appear when presented in the form of a concatenation of characters, in accordance with the invention; and
FIG. 4 is a block diagram of the functional elements involved in the concatenation of personal data and their use both outside the card and on the card.
DETAILED DESCRIPTION
Before dealing with the specific features of customisation in accordance with the invention, the general architecture of an open programmable smart card will be described with reference to FIG. 2 . At the heart of the card 1 there is situated a microprocessor (CPU) 2 which provides all the internal management functions of the card, as well as execution of the applications which are programmed therein. The microprocessor is connected by an internal bus system 4 to three types of memory:
a programmable memory of the electrically erasable ROM (EEPROM) type 6 . This memory is intended to be loaded with one or more service applications capable of being executed by the microprocessor 2 ; a memory of the mask ROM type 8 , containing all the code and values of an internal management software program of the card. These data are written during manufacture of the chip. The content of the mask ROM memory 8 is very strongly linked to the hardware means of the smart card, the code normally being designed by the manufacturer of the card; and a memory of the RAM type 10 intended for the storage of temporary data, such as register contents, code blocks to be loaded into the microprocessor, etc.
The internal bus 4 is furthermore connected to a communication interface 12 which constitutes an input and output port with respect to the outside world, and which provides the electrical power supply of the card 1 . This interface can be in the form of connection pads intended to engage with respective contacts of a reader, and/or an antenna in the case of a so-called contactless card. The communication interface 14 is used among other things for bidirectional data exchange with a terminal provided for loading an application into the EEPROM memory 6 .
The general concept of the invention will be described with reference to FIGS. 3 and 4 . In the following description, the communicating portable device is a smart card of the type described with reference to FIG. 2 . It should be understand however that this description can be transposed to any other type of communicating portable device.
FIG. 3 illustrates the preparation of the customisation data by an external centre for the card, for example a server or a remote terminal. The data personal to a card holder are established therein in various ways. In the example, these data have two possible sources:
a local station for direct input on a screen 20 , said screen possibly being integrated with a card reader terminal. In this case, the data can be written directly by the holder by filling in an on-screen questionnaire; and a file of personal information specific to the holder, coming from a database 21 .
The data coming from these sources are processed by a software customisation module 22 in order to be arranged and formatted thereby according to a format pre-established by the customisation protocol laid down with the on-card program forming the subject of the customisation.
The customisation module 22 produces in electronic form a set of personal information elements V 1 to Vn which constitute the data grouped together in corresponding fields E 1 to En. In the figure, this set of information elements is depicted in the form of a table 24 with n different fields, numbered 1 to n, the first five of which are: surname, forename, social security number, height and weight of the card holder.
With each field Ei (i being a number between 1 and n) there is associated a value Vi, that is to say the corresponding personal data item (for example “Durand” for the field “Surname”). As shown in the table 24 , the values Vi can be numeric or alphabetic according to the information to be supplied. A classification, called “type”, is applied to each value Vi according to the length thereof in terms of bytes, in accordance with the following table:
TABLE 1
Correspondence between type and length in bytes.
Type
Length in bytes
Byte Array
>4 (non-deterministic)
Integer
4 (deterministic)
Short
2 (deterministic)
Byte
1 (deterministic)
The Byte Array type is non-deterministic in the sense that its length is not fixed; on the other hand all the other types mentioned are deterministic, their length being fixed.
When the values constitute a byte array, which is in particular the case for the first three fields E 1 , E 2 and E 3 , they are prefixed by the indication of their length in bytes, this indication being coded in two bytes. Thus, for the field E 1 , the byte array starts with “06” in order to indicate that the value “Durand” which follows comprises six bytes (each numeric or alphabetic character occupies one byte).
For the Integer and Short types, the value contained is supplemented, if necessary, by one or two leading padding “0”s in order to obtain the set number of bytes, respectively four and two. By way of example, the field “height” being of Integer type, the value of “178” will be preceded by one “0” in order to form the block of four bytes “0178”.
The values Vn−1 and Vn at the end of the table 24 are respectively of the type “byte” and “short”.
In accordance with the invention, the values expressed by the types for these n fields are subjected to a concatenation operation, so as to produce a string of characters, and therefore of bytes, 26 . To do this, each value Vi is first inserted in a data block Bi, which has the format defined by the type used to express this value Vi. Thus, a data block Bi for the type “byte array” comprises the aforementioned two prefix bytes followed by the bytes which make up the value Vi. The data blocks Bi for the deterministic types (integer, short, byte) are constituted by the byte or bytes of the value Vi itself, possibly with one or more padding “0”s.
Next, a concatenation of these data blocks Bi is created, with no interposition of other data.
The absence in the concatenation 26 of any explicit designation of a field Ei, such as “surname”, “forename”, etc., should be noted in particular.
Thus, as shown by the concatenation 26 , the byte array “06DURAND”, forming the block B 1 for the field E 1 , is followed immediately by the byte array “08PHILIPPE”, forming the block B 2 , etc.
It should be noted that the data group is more compact, on account of it not incorporating the names of the fields in front of each of the values, unlike the conventional approach.
The byte string of the concatenation 26 is transmitted in the form of a stream of bytes to the smart card of the addressee, where it will undergo a reverse operation, referred to as “deconcatenation”, making it possible to extract the data in order to write them into the fields provided E 1 , E 2 , E 3 , . . . , En of the on-card application.
FIG. 4 illustrates the functional means which make it possible to achieve on the one hand the concatenation of the off-card personal data and on the other hand the use of these data in serialised form at the card 1 for customising an application. These functional means are implemented with software modules distributed in the off-card and on-card memories.
In FIG. 4 , the operational parts are indicated by rectangles, and the actions or results coming from these parts are indicated by tablets.
At the off-card customisation means level, there is identified a customisation unit 40 which is used in particular to establish groups of personal information according to the table 24 of FIG. 3 , to use this example again, and a concatenation module 42 which cooperates with this unit 40 in order to achieve the concatenation of values 26 . Transmission means 44 are provided downstream in order to provide the transportation of the concatenation of values 26 to the card.
In operation, the off-card customisation unit creates, for each field Ei, a grouped set of three elements: the name of the field, its type, and the value which has to be written therein.
For each field called up, starting with the first E 1 , the customisation unit sends to the concatenation module 42 the type and the value 46 . From these information elements, the concatenation module will create a block of bytes, the number of which will be laid down by the type, according to Table 1 above. This block will consist of the values themselves and any prefix data indicating the number of bytes in the case of a byte array type and the aforementioned padding “0”s. It should be noted that the block can comprise an arbitrary number of bytes, including a single one (the byte type case).
The first data block corresponding to the first field is then inserted 48 at one end of a register 50 , such as a FIFO type buffer memory, which allows reading of the bytes sequentially in the order of appearance in the block.
Next, the process is repeated in the same way for the following field (loop back L 1 ). Any following block thus obtained is recorded with the first byte situated at the position which immediately follows that of the last byte of the preceding block.
After insertion of the last data block in the register 50 , said register contains the concatenation 26 (that is the serialised data) as depicted in FIG. 3 .
Upon achieving the customisation as regards the card 1 , the serialised data in the register 50 are transferred to the transmission means 44 in order to next be transmitted by a link 52 to this card. The implementation of the transmission means and the link is conventional, being a local link on serial or parallel cable, or a wireless link by infrared or radio beam, or else a link between off-card and on-card remote terminals by telephone line on an Internet type network.
Upon reception of the concatenation of values 26 , said values are stored in a register on the card (or possibly in proximity to the card) observing the order of sequence of the bytes.
The use of these on-card data is provided by a customisation unit 54 which cooperates with a deconcatenation module 56 (also designated by the term “library”). It should be noted that these data transmitted to the card are application data and not commands.
Like the unit 40 , the on-card customisation unit 54 is used to establish a group of elements for each field. In this case, the group comprises two elements which are common with those of the off-card customisation unit 40 , namely the name of the field and its type, for each field E 1 , E 2 , E 3 , . . . , En.
It should be noted that there exists an exact agreement between these elements situated off card and on card. More particularly, there is found at the level of the off-card 40 and on-card 54 customisation units an identity as regards:
the fields E 1 , E 2 , . . . , En forming the subject of the concatenation; the order in which these fields are taken into account for the concatenation and for the deconcatenation respectively off card and on card; and for each field, the type of value contained: byte array, integer, short or byte. However, when the type associated with a field is a byte array, the customisation unit 54 has no need to know its length, this information being specified in the concatenation data 26 received.
This agreement can be pre-established by a convention or it can be obtained by writing the code relevant to this aspect consistently between the off-card and on-card parts.
Besides these two elements (field and type), the aforementioned group of elements of the on-card customisation unit comprises, for each field, a destination address for the value associated with this field. This address, which therefore constitutes the third element of the group, can be the first address value of a memory intended for storing the value in the card.
The on-card customisation process then consists, firstly, of extracting for each field the corresponding value contained in the concatenation data 26 .
To do this, the customisation unit 54 sends to the deconcatenation module 56 a command 58 for extracting the data type corresponding to the field under consideration. In response, the deconcatenation module 56 extracts, from the concatenation data 26 , the bytes of the block which constitute the value of the field. These bytes are identified by the concatenation module simply by the fact that:
on the one hand, the blocks of bytes which constitute the successively processed fields follow one another in the concatenation data 26 , which makes it possible to determine the starting point for the extraction, and
on the other hand, the indication of the type by the command 58 makes it possible to determine the number of bytes to be extracted.
Thus, for the first field E 1 according to the example of FIG. 3 , the type extraction command 58 consists of requesting the deconcatenation module 56 to extract the byte array type. Being the first command 58 , the module positions itself for reading the head of the concatenation data 26 and, in accordance with the process for extracting a byte array, reads the first two bytes, that is “06”. The module is thus informed that it must deliver the following six bytes of the concatenation data, that is those which encode the value “DURAND”. This value is sent as the output 60 from the deconcatenation module 56 to the customisation unit 54 . In response, the latter creates and sends 62 a set of data consisting of this value and its destination address in order to fill in the field. This set is processed by internal management means in order to achieve the storing of this value at the agreed location on the card. The updating (or creation) 64 of the field E 1 , corresponding to the surname, with the value “DURAND” is thus achieved, at the memory location of the card provided for this personal information.
The customisation unit 54 next determines whether there is a following field 66 . If such is the case, it performs a loop back L 2 in order to go to the processing of this field.
For the following field E 2 , the deconcatenation module 56 is also informed that it must extract a byte array. The block of bytes concerned is identified as the one situated immediately following the last byte extracted for the preceding field E 1 . The value “PHILIPPE” in this forename field is thus extracted by an identical process and undergoes the same processing for outputting a value 50 to the customisation unit 54 , for outputting said value with the address of the second field 62 , and for updating the field 64 in order to write the value in the memory location of the card provided for the forename.
The starting point of each operation for extracting a value from the serialised data 26 can be fixed by an address pointer according to conventional techniques.
When all the values of the n fields are thus extracted and stored in the card at the agreed addresses, the deconcatenation process is finished.
One of the remarkable aspects of the invention lies in the fact that the off-card concatenation module 42 and the on-card deconcatenation module 58 are completely generic in the sense that they are independent of specific features of the customisation of a particular service application. This is because these modules do not have to take into account the meaning or purpose of the values they manage. Their function is simply to concatenate them (concatenation module 42 ) and extract them (deconcatenation module 56 ) as blocks of bytes whose size is fixed by the assigned type.
In this way, the off-card concatenation module 42 can be installed in any terminal having the task of transmitting customisation data to a device. A terminal thus equipped can then benefit from the advantages of sending customisation data in serialised form for all the service applications managed.
At card level, one and the same deconcatenation module 56 can serve different customisation units 54 , in particular in the case of an open or closed multiservice card comprising a number of applications, each of which comprises its own customisation unit.
The concept of the invention having been described apart from the considerations specific to the formalism of the software means, for reasons of simplification, these aspects will now be dealt with within the context of an example based on the JavaCard language, commonly used for programming applications on smart cards. The JavaCard language is a derivative of the Java language, which takes account of the hardware resource limitations of the cards, in particular as regards their memory capacity. It is however clear that persons skilled in the art can easily transpose and adapt the elements of this description to any other language used in the field.
As regards the software means, implementation of the concatenation takes place at the following levels:
execution of the customisation code on a machine outside the card, this being for example a customisatipn machine or a remote server; coding of the customisation data which result therefrom into a byte stream (cf. data 26 in FIG. 3 ), using a single and portable format; transmission to the card of the byte stream which results therefrom; and decoding of the byte stream provided by the card using an automated process, implemented by the deconcatenation module 54 .
At the off-card (server) level, the software means comprise a library which allows a user to create and initialise the same objects as those used in the card application, for example files, personal identification codes, and keys. These means also comprise a software tool (concatenation module 42 ) which can input these objects (after initialisation) and transform them into a byte stream 26 , which is coded in a single and transportable manner.
At the level of the card 1 , the software means comprise a generic reading tool (deconcatenation module 56 ) whose function is to decode the generic part of the byte stream. For each object type which can be created, a specific function is provided for decoding the part of the byte stream which describes this particular object type.
The implementation of the software means is a function of the type of customisation machine and the type of card used.
By way of example, the concatenation (and, conversely, the deconcatenation) can be based on a concatenation format adapted to the “JavaCard” language.
When a customisation machine is used in a secure environment, the byte stream does not necessarily have to be made secure by encryption, and the raw data, including a few checksum values, can be transmitted on the line between the customisation machine and the card.
When a remote server is used (for example via the Internet), the communication must preferably be made secure, and the byte stream will then be encrypted and signed (for example using a protocol of the type known by the acronym MAC, for “Message Authentication Coding”). In certain cases, it is possible to encrypt only the sensitive part of the data stream.
With an open card in which applications can be written by third parties and loaded into the card, the main library of the card, that is the deconcatenation module, will be included in the software operating tool, normally in ROM fixed memory, but the libraries which decode the content of each object, that is the customisation unit 54 , will be contained in the application which defines the object.
With a closed card, the whole of the card library will be integrated in the software operating tool and the set of potential objects will be fixed.
There will now be considered an application in the “JavaCard” language which can be customised by a remote server through a network. For reasons of simplification, this will concentrate on the particular case of an object created for the personal identification code (PIN Object). In the example, the data transmitted are:
the maximum number of code writing attempts permitted; the maximum size of the PIN code; the actual size and the value of the PIN code; the initial number of possible attempts.
The idea is then to define two additional methods in the PIN object: one for writing the PIN data and the other for reading these PIN data.
A method for writing PIN data into a stream on the server can be as follows:
Public void writeStream (ObjectOutput out) throws IOException
{
out.writeByte(maxTries);
out.writeByte(maxSize);
out.writeByte(actualSize);
out.write(PINValue, (short)0,
actualSize);
out.writeByte(ratif);
}
This method will be designated “writeStream( )”.
In a corresponding manner, a method for reading PIN data from a stream (on the card) can be as follows:
Public void readStream(ObjectInput in) throws IOException
{
maxTries =
in.readByte( );
maxSize =
in.readByte( );
actualSize =
in.readByte( );
in.read(PINValue, (short)0, actualSize);
ratof = in.readByte( );
}
This method will be designated “readStream( )”.
With the “JavaCard” software means, the byte stream which results therefrom must contain all the information described by the user, as well as system information intended to be used by the generic decoder on the card, that is:
the AID of the set in which the class is defined. (An AID is an identification code assigned by an international standards organisation for listing applications.);
and
the token of the class within the set. (A token is a way of identifying a class by a hexadecimal number rather than by a name, in order to save on-card memory space.)
Consequently, if a PIN personal code is used under the following conditions:
definition in the set com.gemplus.util (AID=A0 00 00 00 18 34); the class has the token 0x21 in this set; the PIN personal code is defined with three attempts at most, a maximum size of six, a PIN value of “1234” and a standard maximum number of attempts of three;
then the corresponding byte stream will be:
A0 00 00 00 18 34
AID set
21
Token class
03
Maximum number of attempts
06
Maximum size
04 01 02 03 04
Size and value of PIN
03
Size and value of PIN
In other words, the data stream of the concatenation will appear as: A0 00 00 00 18 34 21 03 06 04 01 02 03 04 03.
This data stream can be produced on a server by the method “writeExternal( )” defined above, then encrypted, and next sent to the card, where it will be decoded by the method “readExternal( )” defined above.
The basic idea which has just been described consists of defining a system for representing data in a card and a protocol for loading them into the card. From this context, a number of variants can be envisaged:
1. Instead of producing the data from a simulator, it is possible to use a “master” card which is customised according to a conventional method, and then to obtain the external data from this master card. The data which result therefrom can then be transmitted to other cards. Thus, in accordance with this variant, the “master” card fulfils the function of the off-card means, and all the customisation operations are carried out by cards.
2. The serialised data 26 can be subjected to encryption according to a given cryptographic protocol during their transportation or their storage in memory.
3. The serialised data 26 can be backed up on sites for the purposes of archiving the content of the personal information of a card or performing new customisations.
4. After having produced the backup (cf. variant 3 ), it is possible to keep the applications, known by the term “applets”, in a secure storage place, for example by carrying out an encryption according to variant 2 . The data can also be used for executing an application on another device from the server.
5. A backup system defined in paragraph (2) can also be used at the end of life of a card as a diagnostic or fraud detection tool.
6. The secure backup system defined in paragraph (2) above can be used for exchanging data between cards in a secure manner.
It should be noted that, in one implementation of the invention based on the JavaCard language, it is possible to rely partly on data concatenation techniques already established for this language. These techniques are known in fields very different from those of customisation of applications on portable devices, namely techniques for data backup and task sharing between computers.
The invention can be used both for customisation on a production site, before issue, and for remote customisation, after issue.
In all cases, whether an open or closed card is concerned, the following technical effects are obtained:
a reduction in the size of the customisation code on the card. On the card, the amount of code necessary for the customisation is greatly reduced for a number of reasons. First, a large part of code is generic and included in the system, only one physical location. Next, the code which is specific to each object type is fairly small, and needs to be present only at a single place in the card; facilitation of remote customisation. Since there is only a single byte stream to be transferred, the level of interactivity during the customisation is reduced, and it becomes possible to work with a network even of low quality. In addition, the total amount of data to be exchanged tends to decrease.
Furthermore, it will be appreciated that:
the majority of the customisation code resides outside the card, said card containing only the generic code necessary for decoding the stream; the single byte stream can be made more compact than the conventional customisation scripts, and its structure is very simple, which greatly facilitates transportation of the stream to the card; the customisation machine or the server can keep a detailed archive of the customisation. The customisation code can be merged into the code of the server transparently; the byte stream is independent of the card type used, which can increase the potential for reuse of the customisation scripts; in the case of a “Java” server and a “JavaCard” card, the server can use the software in the card for carrying out initialisation, which substantially reduces the potential risk of errors.
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The customization or initialization of the application, for example in a programmable smart card, uses minimum integrated code. A device for preparing customizing or initializing data to be transmitted to the card creates a concatenation of information elements in respective adjacent data blocks in accordance with a convention recognized by a communication device, without explicit field specification. On reception of a data sequence, the card code identifies the information elements according to their size and their position in the flow.
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The United States Government has rights in this invention pursuant to Contract No. DE-AC04-76DP00789 between the U.S. Department of Energy and AT&T Technologies, Inc.
FIELD OF THE INVENTION
The present invention relates generally to ceramics, and more particularly to a phase transformation-toughened glass ceramic.
BACKGROUND OF THE INVENTION
Glasses are very useful dielectric materials because they can be easily formed into a wide variety of shapes and also because they can be chemically bonded to metals to form a hermetic seal. However, they are brittle materials with low toughness, this being a limit to their use in structural applications. The toughness of glasses may be improved by dispersing in them particulates, such as whiskers and fibers. In most cases however, the improved toughness is accompanied by reduced strength because these additives increase the size of the inherent internal flaws that ultimately cause failure.
Glass ceramics exhibit high strength while still retaining the ability of being easily formed into complex shapes by means of standard glass forming techniques, as well as the ability to form hermetic seals. Glass ceramics are produced by melting a glass-forming batch, cooling the melt and shaping a glass article therefrom, and subsequently heat-treating the glass article within a particular temperature range for the period of time necessary to develop the desired internal crystallization. This crystallization or precipitation process permits precise control of crystal size, volume fraction, and distribution in the final material.
Conventional ceramic processing requires the mechanical mixing of the component crystalline phases, followed by heating. This process results in an inherent lack of homogeneity, along with a strict dependence of the final crystalline microstructure upon the starting materials.
It has been disclosed in the prior art that both the strength and toughness of a conventional ceramic material can be improved by dispersing particles of ZrO 2 in the original mixture of the material. This has been done with alumina ceramics, as reported in "Design of Transformation-Toughened Ceramics" by N. Claussen and M. Ruhle in Science and Technology of Zirconia, A. Heuer and L. W. Hobbs, eds, American Ceramic Society, 1981. It is postulated that the ZrO 2 particles improve the material toughness in the following manner. Assuming that the ZrO 2 is retained in the metastable tetragonal phase, the ZrO 2 particles are transformed into the stable, monoclinic phase in the stress field near a crack tip and shield the crack tip from an applied stress. Because the crystals can be kept small and still can be transformed, the inherent flaws that they introduce are also small, and the strength of the material is thereby increased. It should be noted that these ZrO 2 particles are initially added to the original starting materials and remain as crystalline ZrO 2 throughout the entire processing sequence.
The use of zirconia in glass ceramic bodies has also been disclosed. For example, in U.S. Pat. No. 3,252,811, zirconia is incorporated as a nucleating agent to produce a transparent glass ceramic body with very high strength and excellent resistance to thermal shock. The use of TiO 2 and ZrO 2 as nucleating agents in glass ceramic articles is taught in U.S. Pat. Nos. 3,926,660 (Andress et al) and 4,126,477 (Reed). A glass ceramic that is particularly adapted for incorporation of radioactive waste is shown in U.S. Pat. No. 4,314,909 (Beall et al). The process for making the glass ceramic employs cubic or tetragonal ZrO 2 solid solution.
Incorporation of tetragonal ZrO 2 in a glass matrix has also been disclosed. For example, in an article entitled "A Structural Study of Metastable Tetragonal Zirconia in an Al 2 O 3 -ZrO 2 -SiO 2 -Na 2 O Glass Ceramic System," by G. Fagherazzi, G. Enzo, V. Gottardi, and G. Scarinci in Journal of Material Science, 1980, pages 2693 to 2700, the structural and microstructural properties of metastable zirconia in a glassy system are discussed. The peculiarly small size of the precipitated zirconia crystallites is confirmed in the stabilization of the tetragonal form of ZrO 2 with respect to the stable monoclinic one, and is explained in terms of a contribution to the amount of free energy due to strain energy in addition to the previously hypothesized surface energy. Another article discussing ZrO 2 in a glass system is "Phase Equilibria in Ternary Systems Containing Zirconia Silica" by A. Sircar and N. Brett, appearing in Ceramic Society volume 69, pages 131-135, 1970. The presence of uncrystallized ZrO 2 , remaining as a chemical component of the glass matrix, has also been shown to increase the resistance to attack by aqueous alkali. This is discussed in an article entitled "Chemical Durability of Sodium Silicate Glasses containing Al 2 O 3 and ZrO 2 " by C. R. Das appearing in Journal of the American Ceramics Society, volume 64, No. 4, pages 188-193, April 1981.
It is an object of this invention to provide a glass ceramic toughened with tetragonal zirconia. Another object is to provide a toughened glass ceramic that can be shaped by standard glass-forming techniques. A further object is to provide a glass ceramic that is particularly adapted for use as a structural ceramic insulating material in devices such as neutron tubes and switches. A further object is to provide a glass ceramic particularly suited for forming ceramic fibers for use in composite materials. A still further object is to provide a glass ceramic particularly effective in reinforcing concrete.
Upon further study of the specification and appended claims, further objects and advantages of the invention will become apparent to those skilled in the art.
SUMMARY OF THE INVENTION
In accordance with this invention, a phase tranformation-toughened glass ceramic is prepared by: (a) preparing a mixture of a network-forming oxide, a network-modifying oxide and a substantial quantity of zirconia; (b) heating the mixture at a temperature lower than 1700° C. to obtain a homogeneous melt; (c) heat-treating the mixture at a temperature lower than its melting point and higher than its transition temperature for a period of time short enough to prevent significant transformation of the precipitating tetragonal zirconia into monoclinic zirconia; (d) annealing the mixture at a temperature within the range of 500°-900° C.; and (e) cooling the resulting glass ceramic to ambient temperature.
The mixtures of the invention may also contain nucleating agents, as well as conventional stabilizing agents for tetragonal zirconia.
BRIEF DESCRIPTION OF THE DRAWING
The single FIGURE consists of a triangular plot showing the phase transformation-toughened glass ceramic-forming region of a ternary oxide composition specified in weight percent.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Zirconia (ZrO 2 ) is a relatively abundant oxide with a number of remarkable properties. In "Zirconia-An Overview" by E. C. Subbaro, in Science and Technology of Zirconia, A. H. Heuer and L. W. Hobbs, eds., American Ceramic Society, 1981, the major features of zirconia are discussed. Among the properties discussed are crystal structure, phase transitions, mechanical behavior of partially stabilized zirconia, and stabilization. In particular, it is shown that zirconia exhibits a monoclinic to tetragonal transition at 1170° C. and a reverse transition between 850° and 1000° C., depending on the surface and strain energies associated with the forward transformation. It can thus be seen that this transformation exhibits a large thermal hysteresis. Thus, although the tetragonal zirconia phase is stable above 1200° C., the zirconia spontaneously transforms to the monoclinic form at about 900° C. unless constrained. Zirconia also exhibits a tetragonal to cubic transformation at 2370° C.
According to the method of the present invention, a phase transformation-toughened glass ceramic having improved characteristics of fracture toughness, hardness, and resistance to alkali is produced in the following manner. Initially, a composition of a network forming oxide, a network modifying oxide, and substantial quantities of ZrO 2 is prepared. Preferably, a nucleating agent such as platinum is also included. The composition is then melted to a homogeneous glass at a temperature below 1700° C. In this molten state, objects can be fabricated by means of standard glass forming techniques. At this temperature, ZrO 2 is dissolved in the glass melt and thus does not exist in a crystalline state.
As with conventional glass ceramic techniques, the glass melt may then be quenched to a glass. However, in order to retain an appreciable quantity of the zirconia in the tetragonal phase, the glass melt of the present invention must either solidify to a glass at a temperature above 900° C. or undergo a carefully controlled heat treatment so that the tetragonal zirconia initially formed at 1200° C. does not redissolve and reprecipitate in the monoclinic form.
More specifically, the homogeneous mixture is heat-treated at a temperature lower than its melting point and higher than its glass transition temperature. At a heat treatment temperature of about 1200° C., a minimum period of about one hour is required, with no maximum limit indicated. Heat treatments at 1200° C. to 800° C. require minimum times ranging from about 15 minutes to three hours, depending on particular glass melt compositions. In any case, once the tetragonal zirconia has precipitated from the glass melt, the heat treatment should not continue for more than 15 to 30 minutes, unless a stabilizing agent is present. In the latter case, a treatment of 30 to 60 minutes can be carried out.
Heat treating the glass mixture in this manner yields tetragonal zirconia crystals of such a large size that, unlike those of Fagherazzi et al (discussed earlier), they are not stabilized by surface energy effects. They are metastable, and they do transform to the monoclinic form under mechanical stress, thus producing a toughening effect in the glass ceramic. The glass ceramic obtained in this manner further possesses excellent resistance to attack by aqueous alkali because of the presence of the uncrystallized zirconia which remains in the glass matrix.
It should be noted, before ending the description of the process of the invention, that all glass ceramics should be annealed after ceramming to relieve internal stress in their glass matrix phase. The specific appropriate times and temperatures are easily determined by methods well established in the prior art. A temperature within the range of about 500° to 900° C. will generally accommodate most compositions.
A number of network-forming oxides have been found to exhibit the necessary criteria for forming the glass ceramic of the present invention. Among them are SiO 2 , Al 2 O 3 , B 2 O 3 , and mixtures thereof. The network-modifying oxides act as fluxes to promote dissolution of the ZrO 2 in the glass met and also lower the melting point and the viscosity of SiO 2 . Among the network-modifying oxides which have been found to be satisfactory include Na 2 O, K 2 O, Li 2 O, Rb 2 O, CaO, and mixtures thereof. Although ZrO 2 crystallizes spontaneously from the various network-forming oxides, the addition of a nucleating agent such as platinum improves the evenness of the crystal dispersion.
All these materials are used in conventional glass-forming proportions, and many of them may be added in the form of a precursor compound which yields the final glass component under glass-forming condition. For example, platinum may be added as chloroplatinic acid to yield finely dispersed metal in the glass.
The addition of an agent which stabilizes the tetragonal zirconia crystals in the glass both enhances the properties of the material and facilitates its processing. The stabilizing agent reduces the transformation temperature of tetragonal zirconia to below 1200° C., thereby allowing the ceramming temperature to be decreased and/or lengthening the duration of the ceramming heat treatment. Reduction of the ceramming temperature allows better control of crystal size and morphology and permits the precipitation of crystalline phases other than zirconia, thus further enhancing the mechanical properties of the glass ceramic. Increasing the duration of the ceramming step also affords greater control of crystal growth, at a temperature below that of the tetragonal to monoclinic transformation. As it often happens, in melts of low viscosity at temperatures below the transformation temperature, the initially precipitated tetragonal zirconia dissolves and reprecipitates in the monoclinic form in less than ten minutes, a period that is too short for adequate process control. A stabilizing agent will prolong this period to a manageable duration.
The stabilizing agents are conventionally used for preserving tetragonal zirconia in nonglass ceramics. In these instances, they are included with the monoclinic zirconia in the initial powder mixture and, on heating, they diffuse into the tetragonal zirconia formed. In glass ceramics, on the other hand, tetragonal zirconia crystallizes out of the molten mixture, and the stabilizing agent must partition strongly into the tetragonal zirconia and out of the melt. Y 2 O 3 and Sc 2 O 3 do this better than MgO and CaO, and are thus preferred. The quantity of stabilizing agent to be added depends on the quantity of ZrO 2 precipitated and the manner in which it partitions into the ZrO 2 . Since only a small weight-percent dissolved in the ZrO 2 will lower the transformation temperature quite substantially, only very small quantities of the agents, e.g., 0.1 to 1.0 percent by weight of melt, need be added.
Typical glass melt compositions of the invention can contain, on a weight basis, about 61 to 65 percent SiO 2 , 10.5 to 15 percent Na 2 O, and 21 to 28 percent ZrO 2 . These relationships are illustrated in the accompanying FIGURE. On reference to that FIGURE, which is a triangular plot, there can be seen, around point 10, a phase transformation-toughened glass ceramic-forming region for the SiO 2 -Na 2 O-ZrO 2 system. Other compositions containing these compounds, which do not yield phase transformation-toughened glass ceramics are shown at point one to six. These failures to form the desired product are attributable either to the fact that they produce crystalline precipitates other than ZrO 2 (e.g., ZrSiO 2 or Na 2 ZrSi 2 O 7 ) or to their possession of a glass transition phase temperature that is too low to retain the tetragonal phase of ZrO 2 .
EXAMPLE A
A specific example of the phase transformation-toughened glass ceramic within the region shown in the FIGURE can be seen at point 10. The sample composition contained, on a weight basis, 63.5 percent SiO 2 , 11.5 percent Na 2 O, and 25.0 percent ZrO 2 , as well as 0.01 percent Pt. The composition was melted at 1700° C. to form a homogeneous liquid which was readily quenched to a glass. The glass was then reheated to 1200° C. for three hours. It was found that 4.5 percent of the ZrO 2 had crystallized and 75 percent of that quantity was finally retained in the tetragonal phase. The small amount of tetragonal ZrO 2 resulted in a dramatic increase in fracture toughness, i.e., from 0.95 MNm 1/2 for the uncerammed material to 1.5 MNm 1/2 for the glass ceramic. The glass ceramic had a thermal expansion of 70×10 -7 ° C., a value which matches that of Kovar, titanium, platinum and also alumina ceramics.
Other glass ceramics, which--with different heat treatments - have yielded tetragonal ZrO 2 , are shown in the table below.
______________________________________ Percent by Weight B C D E______________________________________SiO.sub.2 53 46 57ZrO.sub.2 25 28 21Li.sub.2 O 2 11 5K.sub.2 O 20 15 --B.sub.2 O.sub.3 -- -- 17Y.sub.2 O.sub.3 -- -- -- 0.5______________________________________
Compositions D and E were melted at 1650° C., then heat-treated (cerammed) at 1000° C. for 15 minutes in the case of D, and for 30 minutes in the case of stabilizing agent--containing E.
It should be appreciated again that the zirconia of the present invention is dissolved in a homogeneous melt of the starting materials and precipitated out of the homogeneous melt as crystalline ZrO 2 . This process involves precise control of the melt chemistry and temperature since otherwise, zirconia can readily crystallize with other chemical species rather than form pure ZrO 2 crystals. It should further be appreciated that zirconia particles cannot be simply added to a glass melt since these particles will dissolve or settle to the bottom of the crucible or furnace and not be homogeneously dispersed in the glass melt.
A plausible alternative method for incorporating tetragonal zirconia in a glass matrix, which has been considered, consists in simultaneously heating and pressing a powered glass/zirconia mixture. However, calculations have indicated that the zirconia would transform on cooling so that the method cannot be considered satisfactory. Furthermore, the number and complexity of shapes that could be formed by such a method are as severely limited as they are with conventional (non-glass) ceramic processes.
Two principal areas of usage have been identified for the phase transformation-toughened ceramic of the present invention. First, the material functions well as a structural insulation in devices such as neutron tubes or switches. Second, the material can be drawn into alkali resistance glass ceramic fibre for use in composite materials. These fibers are particularly well suited for reinforcing concrete, such as is used in explosive bunkers and reactor containment buildings. In this type of application, hardness, corrosion resistance, toughness, and low cost all constitute important properties, and the glass ceramic of the present invention should prove superior to all other materials in current use.
Homogeneity would also be inherently absent, and the crystalline microstructure would be strictly dependent on the starting materials.
Although the present invention has described the use of zirconia as the phase transformation toughening materia other substances exhibiting similar properties could be substituted for zirconia. One such substance is HfO 2 .
Thus, while the present invention has been described with respect to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that variations and modifications can be effected within the scope and spirit of the invention.
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A phase transformation-toughened glass ceramic and a process for making it are disclosed. A mixture of particulate network-forming oxide, network-modifying oxide, and zirconium oxide is heated to yield a homogeneous melt, and this melt is then heat-treated to precipitate an appreciable quantity of tetragonal zirconia, which is retained at ambient temperature to form a phase transformation-toughened glass ceramic. Nucleating agents and stabilizing agents may be added to the mixture to facilitate processing and improve the ceramic's properties. Preferably, the mixture is first melted at a temperature from 1200° to 1700° C. and is then heat-treated at a temperature within the range of 800° to 1200° C. in order to precipitate tetragonal ZrO 2 .
The composition, as well as the length and temperature of the heat-treatment, must be carefully controlled to prevent solution of the precipitated tetragonal zirconia and subsequent conversion to the monoclinic phase.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application No. 60/529,686 filed Dec. 15, 2003, and Provisional Application No. 60/589,297, filed Jul. 20, 2004.
BACKGROUND OF THE INVENTION
[0002] This invention relates generally to vehicle seating and more particularly to a tourist/coach class aircraft seating arrangement. Aircraft seating is typically divided into various classes, for example first class, business class, and coach or tourist class. For each class of seating, an individual passenger is allotted a preselected amount of space (both area and volume). First-class seats provide the most individual space, and also may include features to improve comfort, such as fully reclining sleeper functions. In contrast, the tourist/coach class is provided with a relatively small amount of space, in order to provide the most efficient transportation and lowest cost.
[0003] It has been found that passengers are more satisfied by a given quantity of space when that space is completely controlled, or “owned” by the passenger. Since the space for coach-class seating is limited, it is especially important that a passenger's personal space be protected from intrusion from other passengers. However, prior art coach class seats are typically arranged such that passengers seated side-by side must share an a single armrest. In this arrangement, the armrest width allotted to each passenger, and the dividing line between adjacent seats, is not clearly delineated. This can lead to conflicts between passengers as each tries to assert control of the single armrest, as well as discomfort of the passenger that gets a smaller portion of the armrest.
BRIEF SUMMARY OF THE INVENTION
[0004] Therefore, it is an object of the invention to provide a vehicle passenger seat which is clearly separated from an adjacent seat.
[0005] It is another object of the invention to provide a privacy divider between adjacent passenger seats.
[0006] It is another object of the invention to provide a seat having a privacy divider which still provides a full-width armrest to a passenger.
[0007] These and other objects of the present invention are achieved in the preferred embodiments disclosed below by providing an armrest apparatus for a passenger seat including a longitudinally-extending center armrest adapted to be disposed between side-by-side first and second seats, and a privacy divider attached to the center armrest. The privacy divider is moveable between a stowed position wherein an upper surface of the center armrest is accessible by an occupant of the first or second seat, and a deployed position wherein the privacy divider extends to the center armrest and forms a generally vertically extending wall between of occupants of the first and second seats.
[0008] According to another embodiment of the invention, the armrest apparatus further includes at least one auxiliary armrest attached to a left or right side of the center armrest. The auxiliary armrest is moveable between a retracted position, and an extended position in which the auxiliary armrest provides a laterally-extending support.
[0009] According to another embodiment of the invention, the auxiliary armrest is pivotally attached at an inboard edge thereof to the center armrest.
[0010] According to another embodiment of the invention, the armrest apparatus further includes means for selectively retaining the armrest in the extended position.
[0011] According to another embodiment of the invention, the center armrest includes a wall-like upright support having a top member attached thereto. Movement of the auxiliary armrest to the extended position exposes a space between the upright support and the retracted position of the auxiliary armrest. The space is adapted to accommodate a passenger's thigh.
[0012] According to another embodiment of the invention, the privacy divider includes a plurality of generally triangular panels pivotally mounted about a common axis.
[0013] According to another embodiment of the invention, the panels are linked together such that motion of a first one of the panels towards the deployed position causes motion of the remainder of the panels towards the deployed position.
[0014] According to another embodiment of the invention, the armrest apparatus further includes a second auxiliary armrest attached to the other of the left or right sides of the center armrest and moveable between a retracted position, and a extended position in which the auxiliary armrest provides a laterally-extending support
[0015] According to another embodiment of the invention, the panels are pivoted near a rear end of the center armrest and pivot downwards and forwards when deployed.
[0016] According to another embodiment of the invention, the panels are pivoted near a front end of the center armrest and pivot upwards and forwards when deployed.
[0017] According to another embodiment of the invention, one of the panels includes a cover which is disposed flush with an upper surface of the center armrest when the privacy divider is in the stowed position.
[0018] According to another embodiment of the invention, a passenger seat unit includes: a frame for being attached to a floor of a vehicle; first and second seats carried side-by-side on the frame, each of the seats including a seat bottom for supporting a passenger and an upwardly-extending seat back attached to the frame; a forwardly-extending center armrest disposed between the first and second seats; and a privacy divider. The privacy divider is moveable between a stowed position wherein the armrest is accessible by an occupant of the first or second seat, and a deployed position wherein the privacy divider extends to armrest so as to mutually block access of occupants of the first and second seats from each other.
[0019] According to another embodiment of the invention, the passenger seat unit further includes at least one auxiliary armrest attached to a left or right side of the center armrest. The auxiliary armrest is moveable between a retracted position, and a extended position in which the auxiliary armrest provides support for an arm of a passenger seated in one of the first and second seats.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The subject matter that is regarded as the invention may be best understood by reference to the following description taken in conjunction with the accompanying drawing figures in which:
[0021] FIG. 1 is a perspective view of a passenger seat set including a privacy divider;
[0022] FIG. 2 is a perspective view of the passenger seat set of FIG. 1 showing the privacy divider in a partially deployed position;
[0023] FIG. 3 is a perspective view of the passenger seat set of FIG. 1 showing the privacy divider in a fully deployed position;
[0024] FIG. 4 is a partial perspective view of the passenger seat set of FIG. 1 showing details of a center armrest thereof;
[0025] FIG. 5 is another partial perspective view of the passenger seat set of FIG. 1 showing details of a center armrest thereof, with the privacy divider in a partially deployed position;
[0026] FIG. 6 is another partial perspective view of the passenger seat set of FIG. 1 showing details of a center armrest thereof, with the privacy divider in a partially deployed position;
[0027] FIG. 7 is another partial perspective view of the passenger seat set of FIG. 1 showing details of a center armrest thereof, with the privacy divider in a fully deployed position;
[0028] FIG. 8 is an enlarged perspective view of a portion of the privacy divider of FIG. 1 ;
[0029] FIG. 9 is a partial cross-sectional view of an armrest incorporating a folding auxiliary armrest;
[0030] FIG. 10 is another view of the armrest of FIG. 9 , showing the auxiliary armrest in a partially extended position;
[0031] FIG. 11 is another view of the armrest of FIG. 9 , showing the auxiliary armrest in a fully extended position;
[0032] FIG. 12 is a perspective view of an armrest incorporating an alternative embodiment of a privacy divider in a stowed position;
[0033] FIG. 13 is a perspective view of the armrest of FIG. 12 showing the privacy divider in a deployed position;
[0034] FIG. 14 is a perspective view of the armrest of FIG. 12 showing the privacy divider in an alternative deployed position;
[0035] FIG. 15 is cross-sectional view of the armrest and privacy divider of FIG. 12 ;
[0036] FIG. 16 is a perspective view of a passenger seat incorporating an alternative embodiment of a folding auxiliary armrest;
[0037] FIG. 17 is a perspective view of the folding auxiliary armrest of FIG. 16 in a partially extended position;
[0038] FIG. 18 is another perspective view of the folding auxiliary armrest of FIG. 16 in an extended position;
[0039] FIG. 19 is cross-sectional view of the armrest of FIG. 17 ;
[0040] FIG. 20 is a perspective view of a passenger seat incorporating another alternative embodiment of a privacy divider in a stowed position;
[0041] FIG. 21 is a perspective view of the privacy divider of FIG. 20 in a deployed position; and
[0042] FIG. 22 is a cross-sectional view of the a variation of the auxiliary armrest shown in FIG. 16 .
DETAILED DESCRIPTION OF THE INVENTION
[0043] Referring to the drawings wherein identical reference numerals denote the same elements throughout the various views, FIGS. 1-8 illustrate a passenger seat set 10 including a privacy divider. The seat set 10 includes two seats 12 and 14 which are collectively provided with three armrests 16 , 18 , and 20 , each shown in the lowered passenger use position. The seats 12 and 14 include seat backs 22 and 22 ′ and seat bottoms 24 and 24 ′. The seats 12 and 14 are supported by a frame 26 . The frame 26 is mounted on legs 28 and 30 that are in turn mounted to the deck of the aircraft by track fittings of a known type.
[0044] The privacy divider, referred to generally at 32 , is disposed between the seats 12 and 14 and can be stowed in an upright position as shown in FIG. 1 , or deployed as shown in FIGS. 2 and 3 . In the deployed position, the privacy divider 32 separates the passengers in respective seats 12 and 14 , and most importantly blocks each passenger from placing his or her elbow beyond the center of the center armrest 18 . Although the presence of the privacy divider 32 reduces the amount of armrest space available to each of the adjacent passengers, it will increase overall passenger satisfaction, as passengers prefer to have a smaller amount of space which is protected from intrusion from other passengers, rather than a larger amount of space which is not clearly defined.
[0045] As noted above, when the privacy divider 32 is deployed, it consumes at least some of the space normally available on top of the center armrest 18 . Accordingly, the center armrest 18 is provided with a pair of auxiliary armrests 54 a and 54 b attached to the side walls 56 a and 56 b thereof. The auxiliary armrests 54 a and 56 b are folded down against the sidewalls 56 a and 56 b , out of the passenger's way, when the privacy divider 32 is not in use, as shown in FIG. 1 . When the privacy divider 32 is extended, the auxiliary armrests 54 a and 54 b can be folded upward into a horizontal position to provide extra support for the passenger's arm, as shown in FIG. 3 .
[0046] Referring to FIGS. 6 and 7 , the privacy divider 32 comprises a plurality of generally triangular panels 34 , 36 and 38 , each including a pair of divergent side edges 40 a and 40 b which extend between an outer edge 42 (the shape of which may be varied as desired), and an inner apex 44 . The panels 34 , 36 , and 38 are mounted on a common pivot 46 which passes through the inner apex 44 of each panel. One of the panels 34 includes deployment means such as the illustrated handle 48 , which a seated passenger can use to pivot the panel 34 forward and downward until it contacts the center armrest 18 . The privacy divider 32 may also include suitable linking means which cause the panels 36 and 38 to pivot into the deployed position when the panel 34 is moved. In the illustrated example, shown in FIG. 8 , the panel 34 includes a flange 50 at its aft most side edge 40 b which bears against a complementary flange 52 at the forward side edge 40 a of the panel 36 as the panel 34 is pulled forward. A similar linking arrangement may be employed between the panel 36 and the panel 38 . The privacy divider 32 need not be a rigid barrier. Any configuration which will provide separation and privacy between two passengers may be used. For example, the panels 34 , 36 , and 38 could be replaced with a curtain-like structure, such as elasticized fabric (not shown).
[0047] FIGS. 9-11 illustrate the internal structure of the auxiliary armrest 54 a , which is representative of the auxiliary armrest 54 b , in more detail. The auxiliary armrest 54 a comprises a shell 58 including a generally planar upper surface 60 connected to a pair of spaced-apart inboard and outboard flanges 62 and 64 . The inboard flange 62 is attached to the sidewall 56 a of the center armrest 18 by a linkage 68 or other suitable means to allow the shell 58 to pivot between retracted and extended positions. A suitable mechanism is provided to hold the auxiliary armrest 54 a in the extended position. In the illustrated example the linkage 68 is mounted to the shell 58 in such a manner that its elements move into an “over-center” relationship when the auxiliary armrest 54 a is raised (see FIG. 11 ). This prevents the auxiliary armrest 54 a from being lowered until the linkage 68 is manually collapsed.
[0048] FIGS. 12-15 illustrate an alternative embodiment of the privacy divider, referred to generally at 132 , which may be substituted for the privacy divider 32 described above. The privacy divider 132 comprises a plurality of wedge-shaped panels 134 , 136 , 138 , and 140 , mounted on a common pivot 146 which passes through the inner apex of each panel. The uppermost panel 134 has a cover 148 attached thereto. The cover 148 may be padded or upholstered and is received in a slot 150 in the upper surface of the center armrest 18 . For purposes of illustrative clarity, auxiliary armrests 54 a and 54 b are not shown in FIGS. 12-15 . The panel 134 may include deployment means such as the illustrated tab 152 , which a seated passenger can use to pivot the panel 134 upwards and forwards. The privacy divider 132 need only be raised sufficiently to prevent competition or “elbow jousting” between two passengers. Therefore, the completely raised position of the privacy divider 132 may be fully upward so that the cover 148 is nearly vertical, as shown in FIG. 14 , or it could be at some lower position, such as is shown in FIG. 13 . The privacy divider 132 may also include suitable linking means, such as those described above with respect to the privacy divider 32 , which cause the panels 136 , 138 , and 140 to pivot into the deployed position when the panel 34 is moved. The privacy divider 132 need not be a rigid barrier. Any configuration which will provide separation and privacy between two passengers may be used. For example, the panels 134 , 136 , and 138 could be replaced with a flexible, curtain-like structure, such as elasticized fabric (not shown).
[0049] FIGS. 20 and 21 illustrate another alternative privacy divider 232 disposed inside an armrest 18 . It is similar in construction to the privacy divider 132 in that it includes a cover 248 and at least one panel 234 (or a curtain-like structure as described above). In contrast to the pivoting motion of the privacy divider 132 , the privacy divider 232 is deployed or stowed by raising or lowering it in a vertical direction. The panel 234 man be mounted in the armrest 18 by suitable rails or other known structures for this purpose. The cover 248 may also include a tab 252 that a seated passenger can use to manipulate the privacy divider.
[0050] FIGS. 16-19 illustrate an alternative center armrest 18 ′ which incorporates a pair of auxiliary armrests 154 a and 154 b . The center armrest 18 ′ comprises a wall-like upright support 156 and a longitudinally-extending top member 158 , which may be padded and/or upholstered. As illustrated in FIG. 19 , the upright support 156 is relatively thin to minimize passenger space intrusion, and may be flared outwards at the top to provide a mounting surface for the top member 158 . First and second auxiliary armrests 154 a and 154 b are pivotally attached to opposed edges of the top member 158 , for example with hinges 160 a and 160 b , to allow the auxiliary armrests 154 a and 154 b to pivot between retracted and extended positions. Each of the auxiliary armrests 154 a and 154 b includes a top surface 162 which may be which may be padded and/or upholstered as shown. As shown in FIGS. 16-18 , the auxiliary armrests 154 a and 154 b may be individually raised or lowered. Suitable means, for example a friction mechanism, may be provided to prevents the auxiliary armrests 154 a and 154 b from being lowered unintentionally.
[0051] FIG. 19 illustrates the auxiliary armrest 154 a in the extended position and the other auxiliary armrest 154 b in the retracted position. In the retracted position, the auxiliary armrest 154 b provides padding for the thigh of a seated passenger. In the extended position, the auxiliary armrest 154 a provides an arm support as described above. Because of the design of the upright support 156 , which lacks the spaced-apart sidewalls of the center armrest 18 described above, and the auxiliary armrests 154 a and 154 b , there is also a substantial amount of extra width or “thigh room” provided in the extended position.
[0052] FIG. 22 illustrates a variation of the auxiliary armrests 154 a and 154 b , labeled 154 a ′ and 154 b ′. In this variation, the first and second auxiliary armrests 154 a ′ and 154 b ′ are pivotally attached to opposed edges of a top member 158 ′, for example with hinges 160 a ′ and 160 b ′ such that they lie on top of the top member 158 ′ in the retracted position. The auxiliary armrests 154 a ′ and 154 b ′ may be individually retracted or extended by pivoting them through 180°. Suitable means, for example a friction mechanism, may be provided to prevents the auxiliary armrests 154 a ′ and 154 b ′ from being moved unintentionally.
[0053] The foregoing has described a seating arrangement including a privacy panel. While specific embodiments of the present invention have been described, it will be apparent to those skilled in the art that various modifications thereto can be made without departing from the spirit and scope of the invention. Accordingly, the foregoing description of the preferred embodiment of the invention and the best mode for practicing the invention are provided for the purpose of illustration only and not for the purpose of limitation, the invention being defined by the claims.
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An armrest apparatus for a passenger seat includes a longitudinally-extending center armrest adapted to be disposed between side-by-side first and second seats, and a privacy divider. The divider is moveable between a stowed position wherein an upper surface of the center armrest is accessible by an occupant of the first or second seat, and a deployed position wherein the divider extends to the center armrest and forms a generally vertically extending wall between of occupants of the first and second seats. The privacy may include a plurality of linked panels.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This United States (U.S.) non-provisional patent application filed by inventors David Small et al is a continuation and claims the benefit of U.S. non provisional patent application Ser. No. 09/679,722, filed by inventors David Small et al on Oct. 4, 2000, entitled “WATER GUN WITH SOUND EFFECTS MODULE”, now pending, which is a U.S. non-provisional patent application of US provisional patent application Serial No. 60/157,879, filed by inventors David Small et al on Oct. 5, 1999, entitled “WATER GUN WITH SOUND EFFECTS MODULE”.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] [0002]FIG. 1 is a view of an exemplary embodiment of the present invention.
[0003] [0003]FIGS. 2 a through 2 g are views of one embodiment of a sound effects module in accordance with the present invention.
[0004] [0004]FIGS. 3 a through 3 g are views of another embodiment of a sound effects module in accordance with the present invention.
[0005] [0005]FIGS. 4 a through 4 g are views of still another embodiment of a sound effects module in accordance with the present invention.
[0006] [0006]FIGS. 5 a through 5 g are views of still another embodiment of a sound effects module in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0007] Referring to FIG. 1, a water gun generally indicated by the numeral 20 is provided with a sound effects module, generally indicated by the numeral 22 , to provide sound effects in conjunction with the operation of the water gun. In a typical application, the water gun will be of the elastic bladder type, wherein water is forced into the bladder to expand the bladder, with water being expelled from the gun on pulling the trigger of the water gun as a result of the elasticity of the bladder. Water guns of this general type are well known in the art, with merely a sample of such devices being disclosed in U.S. Pat. Nos. 4,591,071, 4,854,480, 5,219,096, 5,735,440 and 5,902,162.
[0008] The sound effects module 22 in a typical application will be connected to a switch actuated by the trigger 21 of the water gun 20 , so that the sound effects will be coincidental with the discharge of water from the water gun 20 . Such sound effects may be fixed, such as simulating a machine gun or the like, or may be user selectable to simulate various real and/or imaginary weapons, such as machine guns, laser or other beam type weapons, other weapons of science fiction, etc. In that regard, any of various sound signal generating devices may be used, such as by way of example, single chip analog or digital storage and playback devices, such as, by way of example, the analog storage and playback devices manufactured by Information Storage Devices, Inc. of San Jose, Calif.
[0009] It is important to note that implementing an air-tight compression chamber to achieve a waterproof environment is not advisable as pressure differentials between the front and rear of the speaker caused from air freight or heat variations would cause the speaker to deform or potentially become damaged. Pressure differentials across the speaker will cause the speaker to have significant distortion during operation.
[0010] In the water gun environment, it is important that the sound effects module is capable of operation in a wet and humid environment and over some significant temperature range, as the water gun 20 may be exposed to relatively cool tap water or left in the sun on a summer day to warm up to 50-75° Fahrenheit above cool tap water temperatures. Accordingly, it is desired to have the sound effects module be water resistant. While absolute water resistance, which might be referred to as “waterproof,” would be ideal, the cost of achieving absolute water resistance may not be justified from an economic standpoint nor required from a functional standpoint.
[0011] [0011]FIGS. 2 a - 2 g , 3 a - 3 g , 4 a - 4 g , and 5 a - 5 g , disclose four exemplary alternate approaches for achieving the desired water resistance of the sound effects module 22 . As is representative of the embodiments of FIGS. 2 a - 2 g , 3 a - 3 g , 4 a - 4 g , and 5 a - 5 g , FIGS. 2 a - 2 g illustrate the general construction of the sound effects module. In particular, adjacent one end of the sound effects module housing 24 is a mylar speaker 26 , sealed around a periphery to the module housing 24 by the configuration of the speaker cover 28 . The mylar speaker 26 has an electromechanical actuator 50 and a speaker cone 52 made of mylar or other water impermeable material. The actuator 50 converts electrical signals to mechanical vibrations. The speaker cone 52 is glued to the actuator 50 so that vibrations of the actuator 50 propagate into the speaker cone 52 . The speaker cover 28 provides protection from mechanical damage for the mylar speaker 26 while also having openings to allow sound created by the mylar speaker 26 to propagate from the speaker cone 52 .
[0012] [0012]FIG. 2 d illustrates an exemplary configuration of the speaker cover 28 . FIGS. 2 a - 2 f illustrate the mylar speaker 26 , the speaker cover 28 , the module housing 24 , a speaker seal 202 , a speaker cover seal 204 , a ring 206 of the speaker cover 28 and a land 208 of the module housing 24 . The mylar speaker 26 closes the end of the module housing 24 so that speaker cone 52 prevents water from entering the module housing. FIGS. 2 a , 3 a , 4 a , and 5 a are magnified views of the seals that may be provided around the speaker cover 28 , the mylar speaker 26 and the module housing 24 in each embodiment. The seal between the end cover 29 and the module housing 24 may be similar to that of the seal provided between the speaker cover 28 and the module housing 24 . The seal between the removable battery door 32 and the end cover 29 may be similar to that of the seal provided between the speaker cover 28 and the module housing 24 . FIGS. 2 g , 3 g , 4 g , and 5 g are magnified views of the seals that may be provided between the cover 36 and the module housing 24 in each embodiment. The seal between the cover 36 and the module housing 24 may be similar to that of the seal provided between the speaker cover 28 and the module housing 24 .
[0013] The speaker cover 28 is fastened to the module housing 24 by fasteners, threads formed on the speaker cover 28 and the module housing 24 or other attachment devices well known in the art. The speaker cover 28 captures the mylar speaker 26 and presses the mylar speaker 26 against the speaker seal 202 . The speaker seal 202 in one embodiment is an “O” ring type of seal. Thus, the mylar speaker 26 and the module housing 24 compress the speaker seal 202 to seal the module housing 24 and mylar speaker 26 . The sound effects module 22 may also include a speaker cover seal 204 . Speaker cover 28 may have a tongue, projection or ring 206 which presses the speaker cover seal 204 against the groove, race or land 208 thereby sealing the ring 206 and land 208 . While both speaker seal 202 and speaker cover seal 204 have been shown, it is understood that only the speaker seal 202 is required to seal the mylar speaker 26 and module housing 24 .
[0014] At the other end of the sound effects module 22 is an end cover 29 with a battery case 30 . A removable battery door 32 couples to the end cover 29 sealing the periphery of the battery case 30 . Batteries 31 may be installed in the battery case. The batteries 31 are electrically connected to circuitry such as a printed circuit board in a compartment 33 . The compartment 33 is sealed at the bottom with a first cover 34 and sealed at the top with a second cover 36 , having a silicon rubber keypad 48 thereon for, sound effects selection, etc., the exact configuration of which will depend upon the sounds effects module, the selections it provides, etc. Covers 34 and 36 typically enclose a printed circuit board with the sound effects device or devices and any supporting circuitry required thereon in a manner to seal the same from both the volume within the sound effects module and the exterior thereof.
[0015] In general, the sealing of the various components making up the module will be by way of O-rings or other elastic seals. For those components which do not need to be disassembled for any reason, alternate assembly techniques, such as ultrasonic welding, solvent welding, or the like could be used. In any event, the output of the electronics generating the sound signal is coupled to the actuator 50 of the mylar speaker 26 through leads not shown, with leads 38 being connected to the trigger switch for turning on the sound effects module when the trigger of the water gun is pulled. The leads 38 extending through the housing 24 to the trigger switch may be sealed by a silicon seal 37 and provided with a strain relief 39 . These basic components, shown in exemplary embodiment form, are in one way or another common to all four exemplary embodiments of FIGS. 2 a - 2 g , 3 a - 3 g , 4 a - 4 g , and 5 a - 5 g.
[0016] In the embodiment of FIGS. 2 a - 2 g , small holes 40 are provided through the lower wall of the module housing 24 to allow the interior volume of the sound effects module (other than the compartments sealed by covers 34 and 36 ) to breathe, allowing the internal pressure within the greater volume of the sound effects module 22 to equal atmospheric pressure. In that regard, it is important that that interior chamber be at or near the outside ambient pressure, as otherwise the speaker cone 52 of the mylar speaker 26 will have a pressure differential there across, providing a stress on the speaker cone and causing a high degree of distortion in the sound generated, in an extreme, perhaps even doing permanent damage to the speaker. At normal operating frequencies of the speaker, however, the holes 40 are too small to allow appreciable flow, so that the internal volume of the sound effects module will act much like a sealed chamber, enhancing the output of the speaker at and near the natural frequency of the speaker/sound effects module air volume.
[0017] In the embodiment of FIGS. 3 a - 3 g , specifically as shown in FIG. 3 e , a pair of one-way valves 300 is provided which prevents the buildup of pressure within the sound effects module housing, though prevents water from entering the housing. A hole 302 in the housing 24 allows pressure within the sound effects module to be equalized through the pair of one-way valves 300 . Various types of one way valves 300 could be used, such as, by way of example, duck bill rubber valves or ball check valves. Such an embodiment would block water flow into the interior of the module, but tend to allow air flow into and out of the interior region. The one way valves are arranged so that one valve allows air to flow into the chamber and the other valve allows air to flow out of the chamber. These valves operate in concert to maintain the pressure of the internal compression chamber at equilibrium with atmospheric pressure.
[0018] In the embodiment of FIGS. 4 a - 4 g , as specifically shown in FIG. 4 e , a hole 400 is provided through the case with a semipermeable filter member 402 mounted therein to allow the passage of air, but not the passage of water, into and out of the interior volume of the sound effects module. The air flow through such a semipermeable filter of the various types as are well known is fairly restricted, so as to have no significant effect on the acoustic properties of the system at the desired frequencies of the sound effects generated by the speaker.
[0019] In the embodiment shown in FIGS. 5 a - 5 g , specifically FIGS. 5 b and 5 e , expansion and contraction of the air within the sound effects module is compensated for by the flexibility of the module housing 24 itself, specifically by the imposition of an accordion type flexible member 42 , sealed with respect to the module housing 24 and end member 44 . A restriction plate 46 in this embodiment closes off most of the end of module housing 24 to define the internal volume of air behind the speaker for acoustic purposes, with a small hole 54 in member 46 allowing very low frequency breathing between the volume behind the speaker cone 52 and the volume enclosed by the flexible member 42 to equalize pressures there between. Thus this embodiment, like the others, maintains the acoustic characteristics of the mylar speaker/air chamber there behind, while at the same time, provides even better water resistance for the sound effects module.
[0020] [0020]FIGS. 5 a - 5 f illustrate the flexible member 42 , the restriction plate 46 , the end member 44 , a seal plate 510 and a cover 512 . To assemble the flexible member 42 to the module housing 24 , the flexible member 42 is presented at the end of the module housing 24 . A skirt 506 of the flexible member 42 is fitted over the lip 508 of the module housing 24 . The skirt 506 may be made from an elastomeric material. A restriction plate 46 is slid into the other end of the module housing 24 . The restriction plate 46 is then screwed into the end of the module housing 24 thereby capturing and compressing the skirt 506 . Thus the skirt 506 seals the flexible member 42 and the module housing 24 . The end member 44 is presented to the flexible member 42 . A seal similar to the module housing 24 and flexible member 42 may be formed between the end member 44 and flexible member 42 using the seal plate 510 . A cover 512 with battery case 30 and removable battery door 32 is sealed to the end member 44 .
[0021] In another embodiment, the restriction plate may have a tongue 502 and the module housing 24 may have a groove 504 . Restriction plate 46 is pushed toward the accordion end of the module housing so that tongue 502 engages groove 504 . Thus the tongue 502 and groove 504 capture and compress the skirt 506 to seal the flexible member 42 and the module housing 24 . In another embodiment, the flexible member 42 is coupled to module housing 24 by ultrasonic welding, solvent welding or the like.
[0022] In the embodiments described herein, the basic sound effects generation has been described with respect to some form of electronic sound effects generator. Other types of sound effects generation and effects of other types may also be generated by the water resistant module of the present invention. By way of example, the sound effects module might have mounted therein a motor with an eccentric weight to introduce a vibration instead of, or in addition to, the sound effects, the eccentric weight simulating the recoil of a machine gun type device. As a further alternative, the eccentric weight might be comprised of one or more washer type rings on an eccentric pin, positioned to intercept a rigid wall or end of the sound effects chamber, so as to create a firing noise every time the washer or washers strike the end wall on each rotation of the eccentric, thus generating both the desired noise and vibration from the same device. Other alternatives may include lights, pumps or other devices protected within the water resistant module. These and other alternate embodiments will be apparent to those skilled in the art. Thus, while the present invention has been disclosed and described with respect to certain specific embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.
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A water resistant audible toy, such as a toy water gun, includes a speaker having a water resistant speaker cone. The water resistant audible toy includes a switch to activate the speaker to generate sounds. The water resistant audible toy may further include a light to generate lighting effects and a motor to generate a vibration. A pressure equalizer may be further included in the water resistant audible toy. Seals may be provided as part of the water resistant audible toy. The toy water gun includes a trigger to actuate the switch. The speaker may be part of a water resistant sound effects module.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention involves a device for turning and feeding bundles or stacks of flat workpieces so that further processing operations can be performed.
2. Description of Related Art
The manufacture of bags typically starts with the provision of flat-lying tube sections. Stacks of these tube sections, which were previously made in what is referred to as a tube drawing machine, must again be separated in order to be able to feed the separate tube sections, one after another and in proper position, to what is known as a floor feeder of a bag manufacturing system. Rotary feeders, into which successive stacks to be separated are loaded, are often used to separate bundles made of tube sections. A rotary feeder of this type is known from DE-PS 1,277,655, for example.
The tube section bundles or stacks to be separated must be loaded, turned or unturned, into the rotary feeder. The orientation of the bundles will depend on whether or not filling valves should be attached at the front or rear thereof. The particular attachment of the filling valves to the rear or front ends of the bags to be manufactured is important, for example, when the valves are to be fitted to imprints found on the bags.
It is known to manually place tube section bundles into the rotary feeder, in turned or unturned form, according to the side on which the filling valves are to be attached during bag manufacture.
SUMMARY OF THE INVENTION
One object of this invention is to create a device with which bundles, and preferably stacks made of flat workpieces, can be fed, in turned or unturned form, to a subsequent conveyor or subsequent processing devices.
This object is achieved, according to the invention, by providing a particular device for turning and feeding bundles or stacks of flat workpieces. A support bracket is seated in bearings in a frame so as to rotate or pivot. The device is provided with a rotary or pivot drive and guideways running crosswise for rods that can be moved back and forth by a drive. The rods support a beam, parallel to the support bracket, which is connected perpendicularly to a number of arms that are parallel to each other. The device also includes a crosswise support bracket which is connected to the support bracket by joining pieces and which supports tines oriented approximately parallel to the arms.
The bundles can be received from a supply conveyor or other such device and fed to a subsequent conveyor or to a subsequent processing device. In this way, the bundles in the device can be clamped on edge for the purpose of pivoting between the mutually parallel arms, on the one hand, and mutually parallel tines, on the other hand, which form surfaces that can be moved together. Packages can thus be received and fed to a subsequent conveyor or a subsequent processing device either unturned or after being turned on edge by approximately 135° or more.
The support bracket carrying the arms is seated in bearings in two opposing support bracket pieces which are guided in the same direction and mutually parallel in side parts of the side posts of the frame. In this way, a height compensation between the receiving station and the delivery station can be managed. Furthermore, height compensation must normally occur if the bundles to be fed are to be turned between the receiving station and the delivery station.
The support bracket forms the middle piece of a U-shaped frame having a side leg which is seated in bearings in the support pieces so that it can be swiveled around an axis parallel to the middle piece. A support piece can have a swivel drive for the frame.
In a further embodiment of the invention, the support bracket is provided with guideways running crosswise for guide rods which are essentially parallel to the tines and are connected, by a traverse parallel to the support bracket, to joining pieces of the crosswise support bracket carrying the tines. A drive is provided which moves the guide rods back and forth. Exactly positioned receipt and delivery of the bundles with a suitable control, especially before and after a horizontal swing, are made possible.
The drive can include toothed racks which are parallel to the guide rods and engaged by pinions which drive them.
In a further embodiment of the invention, the guideways for the rods carrying the beam by the arms and the guideways for the guide rods which carry the crosswise support by tines are arranged with corresponding drives in a slide carriage which can be moved on the support bracket. In this way, the bundles to be received can be received in a proper position and aligned in a proper position for delivery.
To move the slide carriage, a hydraulic piston-cylinder unit can be provided.
The rods which move the beam back and forth with the arms are the piston rods of the hydraulic piston-cylinder units.
Preferably, bearing pieces are guided on the outer arms so that they are lengthwise movable and fixable. In the bearing pieces, a shaft is seated in bearings such that it can be moved by a drive. The shaft supports stopper plates that clamp between the tines and can be swung until approximately in the plane of the arms.
Good alignment, delivery and receipt of the bundles are ensured when conveyor belts are arranged in the tines so that their conveyor carrying sides rise above the sides of tines facing the arms.
In order to be able to receive and deliver bundles both in unturned and in turned orientations, a supply conveyor is provided for the bundles such that the unit having the arms and tines is seated in bearings in the machine frame. The unit can be lifted, lowered and swung in such a way that the arms and the ends of the tines attached to the crosswise support can be moved under the discharge end of the supply conveyor.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention is described more precisely in the following and is shown in the drawings.
FIG. 1 is a front view of the device for removing bundles from a supply conveyor, or removing bundles from the supply conveyor and then turning the bundles, in which a structural assembly carrying tines is not shown for better viewing;
FIG. 2 is a sectional view of the device along line II--II in FIG. 1;
FIG. 3 is a front view of the device corresponding to FIG. 1 but showing the structural assembly carrying the tines;
FIG. 4 is a sectional view of the device along line IV--IV in FIG. 3;
FIG. 5 is a side view of the structural assembly containing the tines;
FIG. 6 is a front view, partially in section, of the shaft showing stopper plates which can be swiveled and attached on the side arms;
FIG. 7 is a sectional view of the device along line VII--VII in FIG. 6;
FIG. 8 is a side view of the device showing arms under the discharge end of the supply conveyor; and
FIG. 9 is a representation of the device corresponding to FIG. 8 showing the structural assembly containing the tines as movable both under the discharge end of the supply conveyor and in the delivery position above a rotary feeder.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The device for receiving and feeding bundles in the received or turned position is located above a rotary feeder, for example, and includes two side posts 1 of a frame. The side posts are connected, at their upper ends, by a crosswise support 2. At the left end area of the crosswise support 2, a gear motor 3 is mounted. The gear motor 3 has a double sprocket 4 placed on its delivery shaft. Two chains 5 and 6 partially wrap around the double sprocket 4 and carry counterweights 7 and 8 on their strands running out to the left of the double sprocket 4. The other ends of the chains 5 and 6 are attached to slide carriage-type support pieces 9 and 10. The chain 5 is guided over a sprocket 11 seated so as to rotate in bearings in the right end area of the crosswise support 2. Both of the slide carriage-type support pieces 9 and 10 are seated in bearings so that they can be moved in guideways 12 and 13 which are connected to the side posts 1.
In the support pieces 9 and 10, the side legs 14 and 16 of a U-shaped frame are seated in bearings so as to rotate around bearing journals which are flush with each other. The side legs 14 and 16 are connected by a support bracket 15 to form the U-shaped frame. The right side leg 14 is seated in bearings directly mounted on a bearing journal. The journal stands perpendicularly on the right side leg 14 and is mounted in the support piece 10 in such a way that the leg 14 can be swung. The left side leg 16 is firmly attached, via a spacer, to a gear 17 which is seated in bearings in the support piece 9 so that it can be rotated. On the support piece 9, a gear motor 18', with a driven shaft which carries a pinion 18, is flange-mounted as shown in FIG. 2 and 4. The pinion 18 drives the gear 17 via a chain 17' so that the elements 14, 15 and 16 can be swung via the gear motor 18'.
The counterweights 7 and 8 ensure that the gear motor 3 can move the frame formed by the elements 14, 15 and 16, even vertically, without problems.
The support bracket 15 forms a horizontal channel web piece of the U-shaped frame. Plates 21 and 22 on the support bracket are separated by a defined distance. The plates can be moved via the guide shoes 19 and 20 which frame the support bracket 15. The guide shoes 19 and 20 are welded to the plates 21 and 22. The plates 21 and 22 are connected together by a traverse (not shown) to form a slide carriage which can be moved on the support bracket 15. To move the slide carriage formed by the traverse and the plates 21 and 22, a piston-cylinder unit 35, having a piston rod which is connected flexibly to the plate 22, is connected to an end area of the support piece 15 via a flange on the cylinder.
Cylinders 25 and 26 of piston-cylinder units are connected to the outer sides of the plates 21 and 22. The piston rods 28 of these units support a beam 31 at their ends. The beam 31 is parallel to the support bracket 15. Several arms 32, running out into the open, are attached at right angles on the beam 31 and are spaced apart from one another. The piston rods 28 are guided on guide bushings 29 and 30 attached to the plates 21 and 22 and to the beam 31.
On opposing inner sides of the plates 21 and 22 of the slide carriages, slideways or guideways 23 and 24 are attached crosswise to the support bracket 15. Guide rods 70 of a structural assembly which supports a tine 59 can be moved back and forth in the slideways as is described more precisely below. A shaft 36, driven by a gear motor 37, is seated in bearings in the plates 21 and 22 above the guideways 23 and 24. Two pinions 38 and 39 are fastened by wedges on the shaft 36 at a certain distance from one another and engage toothed racks 71 and 73 parallel to the guide rods 70. The manner in which this engagement occurs will be described more clearly below. The pinions 38 and 39 operate to move the structural assembly supporting tines 59.
The structural assembly supporting the tines 59 will now be explained further with reference to FIGS. 3 and 5.
A crosswise support bracket 58, which is formed from a rectangular beam, supports tines 59 attached perpendicularly to the bracket at equal intervals. The crosswise support bracket 58 is connected into a rectangular frame by joining pieces 56 on opposite sides of the bracket. The pieces 56 are metal sheets and are also connected to a traverse 57 parallel to both the support bracket 58 and the support bracket 15. The traverse 57 also is formed from a rectangular beam. Two support plates 68 and 69 are welded to the traverse 57 in its center area. The plates 68 and 69 are spaced away from each other, extend up, and are connected at their outer sides to the guide rods 70 and on their upper sides to the toothed racks 71 and 73. The toothed racks 71 and 73 engage the pinions 38 and 39 in the manner shown in FIG. 3.
Each of the tines 59 is formed from a U-shaped beam with side legs which point in the direction of the guide rods 70. The guide rods 70 run roughly parallel to the tines 59. Conveyor belts 60 are arranged in the groove-shaped recesses of the tines 59 formed by the U-shaped beams. The carrying strand of each of these conveyor belts 60 rises above the side legs of the U-shaped beams. The conveyor belts 60 run over front deflection rollers 61, seated in bearings between the legs of the U-shaped beams, and over rear rollers 62. Each of the rollers 62 is set firmly on a shaft 63 which is seated rotatably in bearings in the plates 56. A sprocket 64 is seated on the shaft 63 and can be seen in FIG. 3. A chain 65 runs over the sprocket 64 and is driven by the sprocket 66 of a gear motor 67. The upper strand 60 of the conveyor belt 60 running in the groove-shaped recesses of the tines 59 is supported by intermediate rollers (not shown). The gear motor 67 is provided with a control by which the conveyor belt 60 can be reversibly driven via the drive mechanism.
Pivoting stopper plates or stopper arms 46 are connected to the external arms 32 in the manner shown in FIGS. 3, 4, 6 and 7. Angle beams 34, having upper legs which point toward each other, are welded to the outer arms 32 formed from rectangular beams. The angle beams 34 form, via upper sides of the arms 32, groove-shaped guideways for slide rods 41 which are firmly attached to the side plates 42. Bolted to the side plates 42 are pot-shaped bearings 43. The journals 44 of a shaft 45, formed from a rectangular beam, are seated, in ball bearings, in the pot-shaped bearings 43. Stopper arms 46, separated by an interval, are attached on the shaft 45 and extend perpendicular to the shaft 45. The shaft 45 is welded to a radial lever 48. The piston rod 49 of a piston-cylinder unit 47, having a cylinder 50 which is flexibly or pivotally connected to one of the side plates 42, is linked to the lever 48. By corresponding activation of the piston-cylinder unit 47, the stopper arms 46 can be swung between the tines 59 and approximately in the plane of the arms 32. This may be seen in FIG. 3.
The shaft 45 with the stopper arms 46 can be moved manually on the outer arms 32 into the desired position. In the desired position, the bearing 43 is then attached to the arms 32. The side plates 42 are provided with channel webs extending to the outside. A retention pin 51 is bolted in the channel webs and clamps on the upper legs of the angle beam 34.
A guide rod is attached on the support bracket 15. The guide rod extends parallel to the support bracket 15. A sensor 40 such as, for example, a photocell or a photosensor, can be moved along and selectively affixed to the guide rod. The sensor 40 can be used to record the respective edge position of the beam 31 and, thus, the position of the slide carriage including the cylinders 25 and 26.
The function of the device for feeding bundles will now be described in connection with FIGS. 8 and 9. The bundles may optionally be turned before they are fed.
In the position shown in FIG. 8, the unit having arms 32 and tines 59 has been moved to the top of the guideways 12 and 13 of the side posts 1 and swung clockwise on end sufficiently far so that the shelf support formed by the arms 32 is located below the discharge end of the supply conveyor 82. In this position, the stopper arms 46 are driven out so that a tube section bundle 55' discharged by the supply conveyor 82 is deposited, when fed, on the arms 32 slanting against the stopper arms 46 in the manner shown. Then, the piston rods 28 of the cylinders 25 and 26 are driven out so that the arms 32 clamp the received tube section bundle 55' against the tines 59. The clamping and conveyor unit containing the arms 32 and tines 59 is then driven by the motors 3 and 18' and swung counterclockwise so that the tube section bundle 55 is transported in the manner shown in FIG. 9 into a position above the rotary feeder 80. In the position shown in FIG. 9, the clamp is opened by moving the arms 32 up. The tube section stack 55 lying on the stopper 81 of the rotary feeder 80 is then deposited on the rotary feeder and separated in the manner shown. In order to ensure a good deposit, the conveyor belts 60 arranged in the tines 59 are driven at a suitable speed while the tines are moved back so that the new tube section stack 55 is deposited in the proper position for the purpose of being separated on the rotary feeder 80.
If the tube section bundles to be deposited on and separated by the rotary feeder 80 are not to be turned after their removal from the supply conveyor 82, then the receiving rake formed by the tines 59 is swung by the gear motor 18 into a horizontal position and driven by the gear motor 3 to the height of the discharge end of the conveyor belt 82. The receiving rake is then driven backwards by a gear motor 37 and the pinions 38 and 39 until its rear end approximately contacts the conveyor belt 42. The stopper arms 46 are swung into the plane of the arms 56 so that a new tube section bundle 55 can be moved up from behind on the receiving rake formed from the tines 59. In order to prevent friction and to ensure a good delivery, the conveyor belts 60 running in the tines are activated until the tube section bundle delivered reaches the front ends of the tines 59 which run out into the open. The stopper arms 46 are then swung inside so that they clamp between the tines 59. The conveyor belts 60 are then driven in the opposite conveyor direction so that the tube section bundle lies against the stopper arms 46. Finally, the tines 59 are driven into the position shown in FIG. 9. The tube section bundle 55 is then placed on the rotary feeder in the manner described.
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The manufacture of bags requires stacks of tube sections to be separated as desired. The stacks must also be able to be turned 180° and then fed to a separating device so that filling valves can be attached to varying end areas. A suitable device for feeding and for turning and feeding bundles includes a support bracket which is seated in bearings in a frame so as to rotate or pivot. The support bracket is provided with a rotary or pivot drive. Guideways, running crosswise relative to the support bracket, are provided for rods which can be moved back and forth by a drive. The rods support a beam parallel to the support bracket which is connected perpendicularly to a number of mutually parallel arms. The device includes a crosswise support bracket which is connected to the support bracket by joining pieces. Tines are supported approximately parallel to the arms.
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STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0001] Not applicable.
REFERENCE TO A “SEQUENCE LISTING”
[0002] Not applicable.
FIELD OF THE INVENTION
[0003] Invention relates to a produce preserver. The preserver absorbs ethylene, given off by produce in a package, reacts with the ethylene thereby removing the ethylene from the package atmosphere. The preferred preserver comprises calcium hypochlorite or sodium hypochlorite and citric acid.
BACKGROUND OF THE INVENTION
[0004] Ethylene is a gas that is given off by fruits, vegetables and flowers during senescence which promotes the ripening and spoilage of the plants. Plants synthesize ethylene. Ethylene is a natural plant growth hormone which has a detrimental impact, even at low concentrations, on the product quality and shelf life of many fruits and vegetables during storage and distribution. Ethylene is sometimes referred to as the ripening or death hormone because it induces fruit ripening and accelerates fruit softening and senescence (aging). Ethylene can also cause a range of post-harvest physiological disorders such as russet spotting on lettuce and scald on apples. Although ethylene is produced by all plants, the principal sources of the low levels of ethylene in the atmosphere are climatic fruits (fruits that ripen after harvest and are characterized by an increase in respiration rate and burst of ethylene production as they ripen), damaged or rotten produce and exhaust gases. Low temperature storage reduces the formation of ethylene by lowering the respiration rate and metabolic rates of the produce. Controlled atmosphere storage with the use of low oxygen and high carbon dioxide concentrations will suppress respiration rates and render the produce less sensitive to the effects of ethylene. The best way to extend the shelf life is to reduce or eliminate the ethylene in the storage atmosphere.
[0005] Patent publications dealing with absorbing ethylene are listed as follows: U.S. Pat. No. 8,057,586 to Powers et al., dated Nov. 15, 2011; EP2044844 to Normenmacher Klaus Prof Dipl-I, dated Apr. 8, 2009; EP0311454 to Allen Davies & Co Limited, dated Apr. 12, 1989; U.S. Pat. No. 4,848,928 to Ausnit, dated Jul. 18, 1989; EP1106233 to Degussa, dated Jun. 13, 2001; EP2525173 to Whirlpool Co, dated Nov. 21, 2012; U.S. Pat. No. 8,152,902 to Wood et al., dated Apr. 10, 2012.
[0006] Packaging technologies designed to scavenge or absorb ethylene from the surrounding environment of packaged produce have been developed. The most widely used ethylene scavenging packaging technology today is in the form of a sachet containing potassium permanganate on an inert porous support such as alumina or silica gel at a level of about 5%. The ethylene is scavenged through an oxidation reaction with the potassium permanganate to form carbon dioxide and water. Although these permanganate based ethylene absorbers are effective at removing ethylene, their use is sometimes accompanied by undesirable effects. These include the possible migration of the potassium permanganate from the sachet onto the produce, lack of specificity to ethylene resulting in undesirable aromas being scalped and a general lack of enthusiasm for the use of sachets. Other types of sachet based ethylene scavenging technologies utilize activated carbon with a metal catalyst such as palladium which converts the ethylene to acetylaldehyde.
BRIEF SUMMARY OF THE INVENTION
[0007] This invention relates to an ethylene absorber comprising at least one member selected from the group consisting of calcium hypochlorite, sodium hypochlorite, potassium hypochlorite, magnesium hypochlorite; and acid and a hydroscopic material.
[0008] In another embodiment, the invention relates to a method of preserving produce comprising placing the produce in a sealed package with a sealed container that allows gaseous contact with the produce in the container with an ethylene absorber comprising at least one member selected from the group consisting of potassium hypochlorite, magnesium hypochlorite, calcium hypochlorite or sodium hypochlorite; and acid and hydroscopic material.
DETAILED DESCRIPTION OF THE INVENTION
[0009] The invention has numerous advantages over the prior art. The invention provides effective control of ethylene in fruit, flower, and vegetable packages. The invention is relatively low in cost and reacts rapidly enough to maintain low ethylene gas content in a fruit or other produce package. The invention may be utilized as a patch or label on the inside of the package or as a sachet. The chemicals utilized in the ethylene absorber are generally safe and low-cost. The reactants absorbed by the instant invention are safe for the user. The invention ethylene absorber will react irreversibly with ethylene and not release ethylene at a later time. The ethylene absorber invention extends the shelf life of fruit, vegetables and flowers. These advantages and others will be apparent from the detailed description below.
[0010] Suitable reactive hypochlorite materials for the invention are calcium hypochlorite, sodium hypochlorite, potassium hypochlorite and magnesium hypochlorite. The preferred reactive materials utilized in the invention ethylene absorber are calcium hypochlorite and sodium hypochlorite because they are very reactive and safe with food products. The hypochlorite materials are combined with a citric acid in a preferred embodiment and will react to form a hypochlorous acid. The hypochlorous acid reacts with ethylene gas to form chloroethanol. Generally the chloroethanol is then absorbed by a reaction products absorber. The reaction of the hypochlorous acid is generally considered to require water to be present. A hydroscopic material is generally considered necessary for the reaction to proceed. Typical hydroscopic materials are zinc chloride, sodium chloride, and sugar. Preferred hydroscopic materials are calcium and zinc chloride as they it will attract water quickly and allow the reaction to proceed.
[0011] Any acid that will react with the hypochlorite to produce the hypochlorous acid may be utilized in the invention. Suitable materials are carboxylic acid, oxalic acid, and carboxylic acids such as acetic acid, formic acid and benzoic acid. A preferred acid has been found to be citric acid as it is very effective, low in cost, safe and available in food grade.
[0012] The reaction products may be absorbed onto any suitable substrate that has efficient absorption of the reaction products. Suitable materials are activated carbon, silica gel, Chabazite, molecular sieve, and activated alumina. Activated carbon and silica gel are preferred for their ability to absorb and hold large quantities of reaction products for the weight of the material.
[0013] The hypochlorite and acid may be utilized in any combination that will react to rapidly and effectively remove ethylene. Generally, the sodium hypochlorite is in about a 10 to 15% chlorine solution. The calcium hypochlorite is dry. The quantities utilized, when used with citric acid, are typically between about equal quantities of citric acid and the sodium hypochlorite solution and up to about three times the amount by weight of hypochlorite solution as the citric acid.
[0014] The invention is a method and material for the irreversible absorption of ethylene. Activated carbon, molecular sieve and zeolites will absorb some ethylene but their capacity is limited. The preferred calcium hypochlorite or sodium hypochlorite and acid such as citric acid will react to form hypochlorous acid. Hypochlorous acid will readily react with ethylene gas to form chloroethanol. Activated carbon is added to the ethylene absorber formulation to absorb the reaction products which are primarily chloroethanol. Other absorbents such as zeolite and molecular sieve also can be sued to absorb the ethylene reaction products.
[0015] The ethylene reactive material of the invention may be placed in any suitable container in the package of vegetables, fruit, or flowers. Vegetables, fruit, and flowers will be referred to herein as produce. Typically the ethylene absorbent material is placed into a container that provides gaseous communication with the packaged produce that is intended to be protected by the absorption of ethylene. The produce package itself would be a typical packaging material that provides substantial protection from flow of water vapor and oxygen into the package. Typical package materials are nylon, polyesters, polycarbonates, and polyolefin such as polyethylene. The container for the ethylene reactive material of the invention would be a capsule, patch, or any other container suitable for placing into a package of produce. The container for the ethylene absorber would have at least one side that is in gaseous communication with the contents of the package. Sachets formed of microporous material such as Tyvek® and other spun bonded or stretched microporous material are known for use in sachets for food and medicine packaging. The absorbent may be placed in a label or patch that would be adhesively placed on the inside of the container where it would not be loose with the produce. The formation of sachets, patches and labels is known in the art.
[0016] The following examples are illustrative and not exhaustive of ways of practicing the invention. Parts and percentages are by weight unless otherwise indicated. The moisture source is 2.5 g of water on blotter paper that is placed into the pouch. In actual use, with produce, water would not be necessary as the produce would provide water.
Example 1
[0017] 0.4 grams calcium hypochlorite
[0018] 0.4 grams citric acid
[0019] 0.4 grams anhydrous calcium chloride
[0020] The above blend was mixed together and placed in a 15 liter pouch containing 100 ppm of ethylene gas in air with a 2.5 gram moisture source. This formulation reduced the ethylene content at room temperature from 100 ppm to 1.0 ppm within 7 days. The analysis was conducted by gas chromatography.
Example 2
[0021] 0.2 grams calcium hypochlorite
[0022] 0.2 grams citric acid
[0023] 0.2 grams anhydrous calcium chloride
[0024] The above blend was mixed together and placed in a 15 liter pouch containing 100 ppm of ethylene gas in air with 2.5 gram moisture source. This formulation reduced the ethylene content at room temperature from 100 ppm to 50 ppm within 10 days. The analysis was conducted by gas chromatography.
Example 3
[0025] 1.0 grams sodium hypochlorite solution (10-15% chlorine)
[0026] 2.4 grams silica gel, B type
[0027] 0.4 grams citric acid
[0028] 0.4 grams anhydrous calcium chloride
[0029] The above blend was mixed together and placed in a 15 liter pouch containing 100 ppm of ethylene gas in air with 2.5 gram moisture source. This formulation reduced the ethylene content at room temperature from 100 ppm to 3 ppm within 10 days. The analysis was conducted by gas chromatography.
Example 4
[0030] 0.4 grams calcium hypochlorite
[0031] 0.4 grams citric acid
[0032] 0.4 grams anhydrous calcium chloride
[0033] The above blend was mixed together and placed in a 15 liter pouch containing 100 ppm of ethylene gas in air with 2.5 gram moisture source. This formulation reduced the ethylene content from 100 ppm to 11 ppm within 2 days at 10° C. The analysis was conducted by gas chromatography.
Example 5
[0034] 0.8 grams calcium hypochlorite
[0035] 0.8 grams citric acid
[0036] 0.8 grams anhydrous calcium chloride
[0037] The above blend was mixed together and placed in a 15 liter pouch containing 100 ppm of ethylene gas in air with 2.5 gram moisture source. This formulation reduced the ethylene content from 100 ppm to 2 ppm within 2 days at 10° C. The analysis was conducted by gas chromatography.
Example 6
[0038] 1.0 grams sodium hypochlorite solution (10-15% chlorine)
[0039] 2.4 grams silica gel, B type
[0040] 0.4 grams citric acid
[0041] 0.4 grams anhydrous calcium chloride
[0042] The above blend was mixed together and placed in a 15 liter pouch containing 100 ppm of ethylene gas in air with 2.5 gram moisture source. This formulation reduced the ethylene content from 100 ppm to less than 1 ppm within 2 days at 10° C. The analysis was conducted by gas chromatography.
Example 7
[0043] 2.0 grams sodium hypochlorite solution (10-15% chlorine)
[0044] 4.8 grams silica gel, B type
[0045] 0.8 grams citric acid
[0046] 0.8 grams anhydrous calcium chloride
[0047] The above blend was mixed together and placed in a 15 liter pouch containing 100 ppm of ethylene gas in air with 2.5 gram moisture source. This formulation reduced the ethylene content from 100 ppm to less than 1 ppm within 2 days at 10° C. The analysis was conducted by gas chromatography.
Example 8
[0000]
0.4 grams calcium hypochlorite
0.4 grams citric acid
0.4 grams anhydrous calcium chloride
3.0 grams St. Cloud 14×50 chabazite dried at 120° C. for 18 hours
[0052] The above blend was mixed together and placed in a 15 liter pouch containing 100 ppm of ethylene gas in air with 2.5 gram moisture source. This formulation reduced the ethylene content from 100 ppm to 10 ppm within 2 days at 10° C. The analysis was conducted by gas chromatography.
Example 9
[0053] 0.4 grams calcium hypochlorite
[0054] 0.4 grams citric acid
[0055] 0.4 grams anhydrous calcium chloride
[0056] 4.0 grams activated alumina UOP D201 7×12
[0057] The above blend was mixed together and placed in a 15 liter pouch containing 100 ppm of ethylene gas in air with 2.5 gram moisture source. This formulation reduced the ethylene content from 100 ppm to 11 ppm within 2 days at 10° C. The analysis was conducted by gas chromatography.
Example 10
[0058] 0.4 grams calcium hypochlorite
[0059] 0.4 grams citric acid
[0060] 0.4 grams anhydrous calcium chloride
[0061] 2.0 grams silica gel, type B
[0062] The above blend was mixed together and placed in a 15 liter pouch containing 100 ppm of ethylene gas in air with 2.5 gram moisture source. This formulation reduced the ethylene content from 100 ppm to less than 1 ppm within 2 days at 10° C. The analysis was conducted by gas chromatography.
Example 11
[0063] 0.4 grams calcium hypochlorite
[0064] 0.4 grams citric acid
[0065] 0.4 grams anhydrous calcium chloride
[0066] 0.5 grams 13× molecular sieve
[0067] The above blend was mixed together and placed in a 15 liter pouch containing 100 ppm of ethylene gas in air with 2.5 gram moisture source. This formulation reduced the ethylene content from 100 ppm to 2 ppm within 2 days at 10° C. The analysis was conducted by gas chromatography.
Example 12
[0068] 0.4 grams calcium hypochlorite
[0069] 0.4 grams citric acid
[0070] 0.4 grams anhydrous calcium chloride
[0071] 0.5 grams 13× molecular sieve
[0072] The above blend was mixed together and placed in a 15 liter pouch containing 100 ppm of ethylene gas in air with 2.5 gram moisture source. This formulation reduced the ethylene content from 100 ppm to 10 ppm within 2 days at 10° C. The analysis was conducted by gas chromatography.
Example 13
[0000]
0.4 grams calcium hypochlorite
0.4 grams citric acid
0.4 grams anhydrous calcium chloride
0.5 grams St. Cloud 14×50 chabazite dried at 120° C. for 18 hours
[0077] The above blend was mixed together and placed in a 15 liter pouch containing 100 ppm of ethylene gas in air with 2.5 gram moisture source. This formulation reduced the ethylene content from 100 ppm to 2 ppm within 2 days at 10° C. The analysis was conducted by gas chromatography.
DISCUSSION OF EXAMPLES
[0078] It was determined that the primary reaction product of ethylene gas and the hypochlorous acid is chloroethanol. The hypochlorous acid is formed by the reaction of the calcium hypochlorite or sodium hypochlorite and an acid such as citric acid. Absorbents were added to the reaction blend to absorb these reaction products. The absorbents tested were activated carbon, silica gel, chabazite, 13× molecular sieve and activated alumina.
[0079] The Examples all illustrate the effectiveness of the invention materials for removing ethylene from the atmosphere of a package in a rapid and irreversible manner.
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This invention relates to an ethylene absorber containing at least one member selected from the group consisting of calcium hypochlorite, sodium hypochlorite, potassium hypochlorite, magnesium hypochlorite and acid and a hydroscopic material. In another embodiment, the invention relates to a method of preserving produce comprising placing the produce in a sealed package with a sealed container that allows gaseous contact with the produce in the container with an ethylene absorber comprising at least one member selected from the group consisting of potassium hypochlorite, magnesium hypochlorite, calcium hypochlorite or sodium hypochlorite; and acid and a hydroscopic material.
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BACKGROUND OF THE INVENTION
When a yarn spun in a pneumatic spinning apparatus or the like is wound on a package or the like, or when a bobbin is changed and re-winding is carried out, if a yarn being wound is broken, the splicing or knotting operation must be conducted. A slack tube is disposed to suck the yarn ends and eliminate yard slack during the splicing operation. However, since this slack tube continues the sucking action even when the splicing operation is not carried out, an unnecessary load is imposed on a sucking system.
SUMMARY OF THE INVENTION
The present invention relates to an improved slacking device in a winder or the like. More particularly, it relates to an improved slack tube which is provided to a winder for sucking a yarn during the splicing or knotting operation.
An object of the present invention is to provide a yarn slacking device by which the load imposed on the sucking system is reduced to a minimum level.
According to the present invention, the sucking action is caused in the slack tube only when the knotting or splicing operation is carried out, while the sucking action of the slack tube is stopped when the knotting or splicing operation is not conducted.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view illustrating one embodiment of the apparatus of the present invention.
FIG. 2 is a side view of the apparatus shown in FIG. 1.
FIG. 3 is a plan view of the apparatus shown in FIGS. 1 and 2.
FIG. 4 is a diagramatic side view illustrating one embodiment of a spinning apparatus.
FIG. 5 is a partial front view of a spinning machine in accordance with the present invention, including a representation of a service truck.
DETAILED DESCRIPTION OF THE INVENTION
One embodiment of the present invention will now be described in detail with reference to the accompanying drawings.
One common main suction tube 1 is laid out on the back portions of units arranged in parallel along the entire width of the machine, and the main suction tube 1 is connected to a suction system (not shown). Slack tubes 2 for the respective units are swingably mounted on the main suction tube 1. More specifically, a slack tube 2 may be loosely fitted in a supporting piece 3 projected from the main suction tube 1, or the supporting piece 3 may be constructed by an elastic member or a bellows member. A suction opening 4 is formed on the end of the slack tube 2, and the suction opening 4 is brought into close contact with a shutter plate 5. In order to bring the suction opening 4 into close contact with the shutter plate 5, the slack tube 2 is always urged to the left in FIGS. 1 through 3 by a spring (not shown). Openings 7 are formed on the shutter plate 5 along running passages of yarns 6 being wound on packages 26 in the respective units so that the distance between every two adjacent openings 7 are the same as the distance between every two adjacent units. A slub catcher 8 is disposed below each opening 7. In the present invention, a first swivelling member is disposed for swinging and moving the slack tube 2 so that the suction opening 4 of the slack tube 2 is communicated with the opening 7 of the shutter plate 5, and a second swivelling member is disposed for swinging and moving the slack tube 2 in the reverse direction. The structures of the first and second swivelling members will now be described.
An L-shaped arm 9 is pivoted on the slack tube 2, and the arm 9 is urged by a spring 10 so that it turns in the clockwise direction in FIGS. 1 and 2. A stopper 11 is disposed on the slack tube 2 to inhibit excessive turning of the L-shaped arm 9. A cam piece 12 is mounted on a frame 13 so that an inclined face 14 of the cam piece 12 is brought into abutting contact with a lower arm portion 15 of the L-shaped arm 9. A bar 16 capable of reciprocating in the longitudinal direction of the machine is disposed above the slack tube 2. A nail piece 17 is mounted on the bar 16. The nail piece 17 falls in abutting contact with the L-shaped arm 9 when the L-shaped arm 9 is brought into abutting contact with the stopper 11. A yarn guide (not shown) is mounted on the bar 16. The yarn guide directs the yarn to the cylindrical feed roller 32 during the winding operation. The bar 16 makes a reciprocating traverse movement during the winding operation and the traverse width is the same as the width of a feed roller 32, and the bar 16 always traverses the yarn so as to prevent wearing of the feed roller which is caused when the yarn is always kept in contact with a specific position of the feed roller.
A knotter truck 20 is disposed to move among a plurality of units arranged in parallel to one another for performing the knotting or splicing operation, and the knotter or splicer truck 20 comprises a yarn joining means 23 and a pair of yarn holding members 28, 30 for holding the yarn ends of a broken yarn and guiding the yarn ends to the yarn joining means 23. Reference numeral 21 represents a swinging arm and when it swings, the end thereof falls in abutting contact with the lower arm portion 15 of the L-shaped arm 9. Reference numeral 22 represents a guide roller.
The operation of the apparatus of the present invention will now be described.
When the slub catcher 8 does not detect a slub or yarn breakage does not occur, the bar 16 makes a reciprocative movement while traversing the yarn. The L-shaped arm 9 is attracted by the spring 10 and kept in abutting contact with the stopper 11. Accordingly, the nail piece 17 is kept in contact with the L-shaped arm 9 and brings the L-shaped arm 9 downward in FIG. 3 with the traverse movement, and the slack tube 2 pivoting the L-shaped arm 9 thereon is kept in the state turned in the counterclockwise direction with the supporting piece 3 being as the fulcrum and the suction opening 4 on the top end of the slack tube 2 is kept in contact with the non-open portion of the shutter plate 5. Therefore, in this state, suction of air from the suction opening 4 is prevented.
When yarn breakage takes place in the above-mentioned state, the knotter or splicer truck 20 stops at a position confronting the unit where yarn breakage takes place, in response to a signal from the slub catcher 8, and the yarn holding members 28, 30 of the truck 20 hold the package side and feed side yarn ends of the broken yarn 6 and guide them to the yarn joining means 23. When the knotter bill of the yarn joining means 23 holds the feed side yarn end, the slack tube 2 is swivelled so that the suction opening 4 of the slack tube 2 is communicated with the opening 7 of the shutter plate 5. More specifically, in response to the signal from the slub catcher 8, the swinging arm 21 turns in the clockwise direction in FIG. 2 and falls in abutting contact with the lower portion 15 of the L-shaped arm 9 to turn the L-shaped arm 9 as indicated by a one-dot chain line. Since the lower portion 15 of the L-shaped arm 9 is brought in contact with the inclined face 14 of the cam 12 at this time, with turning of the lower portion 15 in the counterclockwise direction in FIG. 2, the lower portion 15 moves upward in FIG. 3, with the result that the slack tube 2 which is integrated with the L-shaped arm 9 is swivelled in the direction A in FIG. 3 with the supporting piece 3 being as the center and the suction opening 4 is communicated with the opening 7, whereby the slack tube sucks the yarn end from the opening 7.
After the knotting or splicing operation by the yarn joining means 23 has been completed, by turning of the swinging arm 21 in the counterclockwise direction, the lower portion 15 of the L-shaped arm 9 is set free and the L-shaped arm 9 is returned to the original position indicated by a solid line in FIG. 2 by the elastic force of the spring 10. Accordingly, when the bar 16 making the traverse movement moves downward in FIG. 3, the nail piece 17 falls in abutting contact with the L-shaped arm 9 to press the L-shaped arm 9 downward (in FIG. 3). Therefore, also the slack tube 2 is swivelled to the position indicated in FIG. 3 and the suction opening 4 separates from the opening 7, with the result that the sucking action of the slack tube 2 is stopped.
According to the present invention the opening 4 of the slack tube 2 is communicated with the opening 7 of the shutter plate 5 to suck the yarn on the spinning side into the slack tube at the same time that a knotter bill of the knotter (not shown) holds yarn ends of the package side 26 and spinning side 27 and knots them together. The yarn continuously spun during the knotting operation is sucked and retained in the slack tube 2 thereby preventing an occurrence of kinky threads due to loosening of yarns.
During the operation for guiding the yarns on the package side and feeding side into the knotter 23, the sucking action by the slack tube 2 is not applied to the yarn because the slack tube is shut by the shutter plate 5. So, even if the yarn on the spinning side passes in front of the opening 7 of the shutter plate 5 during the yarn guiding process, the yarn is not sucked into the slack tube, and a miss in the process of guiding the yarn into the knotter can be prevented.
In the embodiment shown in FIG. 4, suction pipe 28 acts as a device for holding the yarn end on the feeding side. The pipe 28, which is able to turn about supporting shaft 29 to the position shown in solid line. turns in the counterclockwise direction sucking the yarn on the feeding side 27 therein and inserts the yarn Ya into the knotter 23 in conjunction with another guide at the position shown by the two dotted line 28a. The yarn end on the package side Yb is sucked into the suction pipe 30, which rotates about shaft 31, and is introduced into the knotter 23. At this time, if the sucking action from the slack tube 2 is effected, the yarn can be held only if the suction force from the suction pipe 28a is larger than the suction force from the slack tube. In the present invention, as aforementioned, it is not necessary to increase the suction force of the suction pipe 28 because the sucking action is not effected at the opening 7 during the yarn guiding operation into the knotter.
As shown in FIG. 5, showing a partial front view of a spinning machine in accordance with the present invention, the relationship between the shutter plate 5 with its elongated openings 7, and the slack tubes 2, the second oascillating member 16, and the nail pieces 17, are clarified based on the description given earlier herein. Additionally, FIG. 5 shows the orientation of the service truck 20, the yarn end holding and guiding members 28 and 30, and the knotter 23.
As will be apparent from the foregoing description, in the apparatus of the present invention, since the sucking action of the slack tube is exerted only during the splicing action and the sucking action is stopped while the yarn is travelling during the winding operation, the load imposed on a blower of the suction system can be reduced to a minimum level. Therefore, the size of the blower can be minimized and consumption of electric power can be reduced.
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A yarn slacking apparatus for slacking and retaining a fed yarn therein during the knotting operation in a winder. The sucking action is caused in the slack tube only when the knotting operation is carried out, while the sucking action of the slack tube is stopped by means of providing a shutter means for an opening of the slack tube, when the knotting operation is not conducted.
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This application is a Divisional Application of prior U.S. patent application Ser. No. 10/246,571, filed Sep. 18, 2002; now U.S. Pat. No. 6,600,049 which is a Divisional Application of U.S. patent application Ser. No. 09/663,336, filed Sep. 18, 2000, now U.S. Pat. No. 6,492,527; which claims the benefit of U.S. Provisional Application No. 60/159,247, filed Oct. 13, 1999.
The present invention relates generally to the field of process chemistry as used in the preparation of commercially valuable chemical products. In particular, it pertains to processes related to 1-aryltriazolinone ring formation and to novel intermediates useful in these processes.
The compound 4,5-dihydro-3-methyl-1-phenyl-1,2,4-triazol-5(1H)-one, among others, is a particularly useful 1-aryltriazolinone critical in the manufacture of commercially important herbicides. For example, U.S. Pat. Nos. 4,818,275 and 5,125,958 fully describe conversions of 1-aryltriazolinone intermediates to known herbicides.
Some known methods for the preparation of 1-aryltriazolinones require formation of a 1-aryltriazolidinone ring followed by conversion of the 1-aryltriazolidinone ring to the desired 1-aryltriazolinone. This requirement is disadvantageous because it adds an additional step to the process of preparing 1-aryltriazolinones. Other known methods provide less than optimum yields of 1-aryltriazolinone because of by-product formation. Given the commercial value of 1-aryltriazolinones, improved processes for their preparation are therefore needed.
SUMMARY OF THE INVENTION
It has now been found that commercially useful 1-aryltriazolinones of formula I
can be prepared in excellent yield and purity by (i) carbonylating an amidrazone of formula (A) with at least one carbonylating agent, or by (ii) condensing a hydrazonoyl derivative of formula (A) with at least one ring-forming agent, wherein formula (A) is
where W, X, Y, Z, and R 1 are fully described below. Preferred are those where W is halogen or —NHR where R is hydrogen or haloalkyl; X and Y are independently selected from hydrogen, chloro, or fluoro; Z is hydrogen, bromo, iodo, nitro, amino, or methylsulfonylamino; and R 1 is methyl. Additionally, certain compounds of formula (A) used to prepare 1-aryltriazolinones of formula I are also novel and are included among the preferred embodiments of the present invention. These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and appended claims.
DEFINITIONS
The modifier “about” is used herein to indicate that certain preferred operating ranges, such as ranges for molar ratios for reactants, material amounts, and temperature, are not fixedly determined. The meaning will often be apparent to one of ordinary skill. For example, a recitation of a temperature range of about 120° C. to about 135° C. in reference to, for example, an organic chemical reaction would be interpreted to include other like temperatures that can be expected to favor a useful reaction rate for the reaction, such as 105° C. or 150° C. Where guidance from the experience of those of ordinary skill is lacking, guidance from the context is lacking, and where a more specific rule is not recited below, the “about” range shall be not more than 10% of the absolute value of an end point or 10% of the range recited, whichever is less.
As used in this specification and unless otherwise indicated the substituent terms “alkyl”, “alkoxy”, and “haloalkyl”, used alone or as part of a larger moiety, includes straight or branched chains of at least one or two carbon atoms, as appropriate to the substituent, and preferably up to 12 carbon atoms, more preferably up to ten carbon atoms, most preferably up to seven carbon atoms. The term “aryl” refers to phenyl or naphthyl optionally substituted with one or more halogen, alkyl, alkoxy, or haloalkyl. “Halogen” or “halo” refers to fluorine, bromine, iodine, or chlorine. The term “ambient temperature” refers to a temperature in the range of about 20° C. to about 30° C. Certain solvents, catalysts, and the like are known by their acronyms. These include the acronyms “DMAC” meaning N,N-dimethelyacetamide, “DMF” meaning N,N-dimethylformamide, “THF” meaning tetrahydrofuran, “DMAP” meaning 4-dimethylaminopyridine, “DBN” meaning 1,5-diazabicyclo[4.3.0]non-5-ene, and “DBU” meaning 1,8-diazabicyclo[5.4.0]undec-7-ene. The term “glymes” refers to a class of solvents comprised of monoglyme, diglyme, triglyme, tetraglyme, and polyglyme. The term “GC” refers to gas chromatography or gas chromatographic methods of analyses.
The term “amidrazone” or “amidrazone of formula (A)” is synonymous with and refers to a 2-(optionally-substituted phenyl)hydrazidethaneimidic acid, for example, but not limited to 2-(2,4-dichlorophenyl)hydrazidethaneimidic acid. The term “hydrazonoyl derivative” or “hydrazonoyl derivative of formula (A)” is synonymous with and refers to a N-(optionally-substituted phenyl)ethanehydrazonoyl derivative, for example, but not limited to N-(2,4-dichlorophyenyl)enthanehydrazonoyl chloride. The term “compound or compounds of formula (A)” refers to both amidrazone and hydrazonoyl derivatives. The term “compound or compounds of formula I” is synonymous with and refers to 1-aryltriazolinone(s), for example, but not limited to 4,5-dihydro-1-(2,4-dichlorophenyl)-3-methyl-1,2,4-triazol-5(1H)-one.
DETAILED DESCRIPTION OF THE INVENTION
One embodiment of the present invention relates to a process for preparing a compound of formula I:
wherein an amidrazone of formula (A) is carbonylated with at least one carbonylating agent, where formula (A) is:
and wherein X and Y are independently selected from hydrogen, halogen, nitro, and amino; Z is selected from hydrogen, halogen, alkyl, alkoxy, nitro, amino, or alkylsulfonylamino; W is —NHR where R is hydrogen, alkyl, or haloalkyl; and, R 1 is hydrogen, alkyl, haloalkyl, alkoxy, acetyl, or aryl.
Preferred species of amidrazone (A) with which to conduct the carbonylation reaction of the present invention are selected from those wherein X and Y are independently selected from hydrogen, chloro, or fluoro; Z is hydrogen, bromo, iodo, nitro, amino, or methylsulfonylamino; R is hydrogen or difluoromethyl; and R 1 is C 1 to C 12 alkyl.
More preferred species of amidrazone (A) are selected from those wherein X, Y, and R are hydrogen, Z is hydrogen, 5-nitro, or 5-amino, and R 1 is methyl, ethyl, or propyl; wherein X and R are hydrogen, Y is 4-chloro, Z is hydrogen or 5-nitro, and R 1 is methyl, ethyl, or propyl; wherein X is 2-chloro or 2-fluoro, Y, Z, and R are hydrogen, and R 1 is methyl, ethyl, or propyl; or wherein X is 2-chloro or 2-fluoro, Y is 4-chloro, Z is hydrogen, 5-bromo, 5-iodo, or 5-nitro, R is hydrogen, and R 1 is methyl, ethyl, or propyl.
Most preferred species of amidrazone (A) are selected from those wherein X, Y, Z and R are hydrogen, and R 1 is methyl; or wherein X is 2-fluoro, Y is 4-chloro, Z and R are hydrogen, and R 1 is methyl.
For conducting the carbonylation of amidrazone (A), the use of at least one suitable organic solvent is preferably employed.
Preferred organic solvents, both polar and a polar, useful in the process of the present invention include halogenated solvents, for example, such as, without limitation, chlorobenzene, carbon tetrachloride, bromodichloromethane, dibromochloromethane, bromoform, chloroform, bromochloromethane, butyl chloride, dichloromethane, tetrachloroethylene, trichloroethylene, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,1-dichloroetane, 2-chloropropane, hexafluorobenzene, 1,2,4-trichlorobenzene, 1-2-dichlorobenzene, fluorobenzene and other halogenated solvents known in the art.
Preferred polar organic solvents include ethers, for example, such as, without limitation, dimethoxymethane, THF, 1,3-dioxane, 1,4-dioxane, furan, diethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, tert.-butyl ethyl ether, tert.-butyl methyl ether and other ether solvents known in the art. Other polar organic solvents useful in the context of the present invention include, for example, without limitation, propionitrile, ethyl formate, methyl acetate, hexachloroacetone, acetone, ethyl methyl ketone, ethyl acetate, nitromethane, nitrobenzene, glymes, and other polar solvents known in the art.
Other organic solvents useful herein include polar aprotic solvents, for example, such as, without limitation, DMF, DMAC, 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone, 1,3-dimethyl-2-imidazolidinone, N-methylpyrrolidinone, formamide, N-methylacetamide, N-methylformamide, acetonitrile, dimethyl sulfoxide, sulfolane, N,N-dimethylpropionamide, tetramethylurea, hexamethylphosphoramide and other polar aprotic solvents known in the art.
Yet other organic solvents useful for implementation of the present invention include protic solvents, for example, such as, without limitation, water, methanol, ethanol, 2-nitroethanol, 2-fluoroethanol, 2,2,2-trifluoroethanol, ethylene glycol, 1-propanol, 2-propanol, 2-methoxyethanol, 1-butanol, 2-butanol, isobutanol, tert.-butanol, 2-ethoxyethanol, diethylene glycol, 1-, 2-, or 3-pentanol, 2,2-dimethyl-1-propanol, tert.-pentanol, cyclohexanol, anisole, benzyl alcohol, glycerol and other protic solvents known in the art.
Further organic solvents useful in the present invention include: acidic solvents, for example, such as, without limitation, trifluoroacetic acid, acetic acid, formic acid and other acidic solvents known in the art; basic solvents, for example, such as, without limitation, 2-, 3-, or 4-picoline, pyrrole, pyrrolidine, morpholine, pyridine, piperidine, triethylamine and other basic solvents known in the art; and hydrocarbon solvents, for example, such as, without limitation, benzene, cyclohexane, pentane, hexane, toluene, cycloheptane, methylcyclohexane, heptane, ethylbenzene, ortho-, meta-, or para-xylene, octane, indane, nonane, naphthaline and other hydrocarbon solvents known in the art.
Organic solvents most suitable for conducting the carbonylation of amidrazone (A) are those that are low cost, best enhance the solubility of the starting materials to promote rate of reaction, and offer minimum solvent decomposition. Accordingly, preferred organic solvents include DMF, DMAC, acetonitrile, toluene, THF, and glymes. More preferred solvents include acetonitrile, toluene, tetrahydrofuran, monoglyme, and diglyme. The most preferred organic solvent in which to conduct the carbonylation of amidrazone (A) is toluene.
In the course of conducting chemical reactions, especially large scale organic chemical reactions yielding commercial quantities of desired product, a balance must be met between having to handle too much solvent and yet provide sufficient solvent to afford optimum reaction conditions. A useful ratio of solvent to amidrazone (A) to afford optimum reaction conditions is in the range of about 2.5/1 to about 20/1 wt/wt, preferably about 3/1 to about 15/1.
In order to form a compound of formula I, an amidrazone of formula (A) is carbonylated with at least one carbonylating agent. Useful carbonylating agents are represented by the following formula:
wherein R 2 and R 3 are the same and are selected from the group consisting of halogen, alkoxy, dichloromethoxy, trichloromethoxy, imidazol-1-yl, 2-methylimidazol-1-yl, phenoxy or naphthoxy wherein phenoxy and naphthoxy are optionally substituted with halogen, alkoxy, or nitro; or wherein R 2 and R 3 are different where, for example, R 2 is halo, and R 3 is alkoxy; provided that if the carbonylating agent is selected wherein R 2 and R 3 are chloro, at least one other carbonylating agent is also selected. Preferred carbonylating agents are those wherein R 2 and R 3 are the same and are selected from the group consisting of dichloromethoxy, trichloromethoxy, imidazol-1-yl, or phenoxy optionally substituted with halogen, alkoxy, or nitro. A more preferred carbonylating agent with which to carbonylate amidrazone (A) is that wherein R 2 and R 3 are each phenoxy. A preferred mole ratio of carbonylating agent to amidrazone (A) is in the range of about 1/1 to about 2.5/1, more preferably about 1.1/1 to about 1.5/1.
Preferably, the carbonylation of an amidrazone of formula (A) to form a compound of formula I is conducted in the presence of an acid or base catalyst. The catalyst need not be present in order to form a compound of formula I; however, its presence will generally accelerate the formation of a compound of formula I. Whether or not a catalyst is preferably present may depend upon the compound of formula I being formed, the amidrazone (A) being used as the reactant, the catalyst, the desired reaction time, and the reaction temperature, which one of ordinary skill in the art can readily determine based on general knowledge and this disclosure.
An acid catalyst useful in the context of the present invention can be a protic (Brontsted) acid or an electron pair-accepting (Lewis) acid. Acid catalysts include, for example, mineral, organic, inorganic, and organometallic acids. Preferred acid catalysts include, but are not limited to, hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, perchloric acid, acetic acid, trifluoroacetic acid, trifluoromethanesulfonic acid, chlorosulfonic acid, methanesulfonic acid, para-toluenesulfonic acid, camphorsulfonic acid, benzenesulfonic acid, boron trifluoride, boron trifluoride etherate, aluminium chloride, zinc chloride, and lanthanum series trifluoromethanesulfonates such as the trifluoromethanesulfonates of scandium, praseodymium, and ytterbium, and other acid catalysts known in the art.
Preferred acid catalysts for use in carbonylating an amidrazone of formula (A) include, but are not limited to, boron trifluoride, aluminum chloride, lanthanum series trifluoromethanesulfonates, methanesulfonic acid, para-touluenesulfonic acid, acetic acid, and trifluoroacetic acid. Particularly preferred acid catalysts include boron trifluoride, scandium trifluoromethadesulfonate, methanesulfonic acid, and para-touluenesulfonic acid.
Preferably, the acid catalyst is present in a mole ratio of acid catalyst to amidrazone (A) in a range of about 0.0001/1 to about 1/1, preferably in a range of about 0.001/1 to about 0.1/1. Additional amounts of acid catalyst can be added if necessary to drive the reaction faster, for example.
Preferred base catalysts include, but are not limited to, alkali metal, alkaline earth metal, and transition metal halides, hydrides, hydroxides, bicarbonates, carbonates, and the like. Metal halides useful in the present context include, but are not limited to, lithium chloride, lithium fluoride, lithium bromide, lithium iodide, sodium chloride, sodium fluoride, sodium bromide, sodium iodide, potassium chloride, potassium fluoride, potassium bromide, potassium iodide, magnesium chloride, magnesium fluoride, magnesium bromide, magnesium iodide, calcium chloride, calcium fluoride, calcium bromide, calcium iodide, silver bromide, and silver iodide. Metal hydrides useful in the present context include, but are not limited to, lithium hydride, sodium hydride, potassium hydride, magnesium hydride, calcium hydride, and barium hydride. Metal hydroxides useful in the present context include, but are not limited to, lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, and barium hydroxide. Metal bicarbonates useful in the present context include, but are not limited to, sodium bicarbonate, and potassium bicarbonate. Metal carbonates useful in the present context include, but are not limited to, sodium carbonate and potassium carbonate. One of ordinary skill, upon receipt of the teachings hereof, may select other alkali metal, alkaline earth metal, and transition metal halides, hydrides, hydroxides, bicarbonates, and carbonates known in the art as catalysts.
Useful base catalysts also include alkali metal alkoxides, such as, without limitation, sodium methoxide, sodium ethoxide, potassium methoxide, potassium ethoxide, potassium tert.-butoxide, and other alkali metal alkoxides known in the art. Other useful base catalysts include organic alkyl amines and cyclic amines, for example, but are not limited to methylamine, ethylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, ethyldiisopropylamine, butylamine, pyridine, DMAP, 2,6-dimethylpyridine, piperidine, piperazine, morpholine, quinoline, DBN, DBU, and other alkyl amines and cyclic amines known in the art.
Preferred base catalysts for use in carbonylating an amidrazone of formula (A) include sodium carbonate, potassium carbonate, sodium hydride, triethylamine, pyridine, DMAP, DBN, DBU, sodium methoxide, potassium methoxide, and potassium tert-butoxide. Particularly preferred base catalysts include sodium carbonate, potassium carbonate, DMAP, DBN, and DBU.
The base catalyst used in the present invention can be present in a mole ratio of base catalyst to amidrazone (A) in a range of about 0.0001/1 to about 1/1, preferably in a range of about 0.001/1 to about 0.1/1. Additional amounts of base catalyst may be added if necessary to drive the reaction faster, for example.
The temperature at which and the period for which a chemical reaction such as the carbonylation of amidrazone (A) is conducted will vary according to, among other things, the solvent or solvents in which the reaction is conducted, the reaction format (e.g., batch, semi-batch, or continuous), the carbonylating agent, and/or the formula of amidrazone (A), and whether or not a catalyst is used. The carbonylation of amidrazone (A) as set forth herein is generally conducted at a temperature in the range of about 10° C. to about 200° C. for a period of time of up to about 20 hours, preferably in the range of about ambient temperature to about 160° C. for about 10 hours, and more preferably up to about 5 hours.
Generally, in a process of carbonylating an amidrazone (A), a hydrazine derivative, for example, 2,4-dichlorophenylhydrazine (1) is first prepared from its hydrochloride salt by treating the salt with a base, such as aqueous sodium hydroxide, giving the free hydrazine (1). The free hydrazine (1) is in turn reacted with, for example, ethyl acetimidate at a temperature of about 0° C. to about ambient temperature in an appropriate solvent such as methylene chloride, yielding the corresponding amidrazone (A), 2,4-dichlorophenylhydrazidethaneimidic acid. Amidrazone (A) is in turn carbonylated with, for example, diphenyl carbonate at a temperature of about 100° C. to about 115° C. in a appropriate solvent such as toluene, yielding the corresponding compound of formula (I), 45-dihydro-1-(2,4-dichlorophenyl)-3-methyl-1,2,4-triazol-5(1H)-one. The carbonylation of amidrazone (A) to the compound of formula (I) is routinely aided with a catalyst, such as DMAP. A detailed procedure for the preparation, and carbonylation of an amidrazone (A) to yield a compound of formula (I) is set forth in Example 3 hereinbelow.
In a second embodiment of the present invention, the process for preparing a compound of formula (I):
involves a condensation reaction of a hydrazonoyl derivative of formula ( A ) with at least one ring-forming agent, where formula ( A ) is:
and wherein X and Y are independently selected from hydrogen, halogen, nitro, and amino; Z is selected from hydrogen, halogen, alkyl, alkoxy, nitro, amino, or alkylsulfonylamino; W is halogen, —NCO, —OSO 2 CH 3 , —OSO 2 CF 3 , or —OSO 2 (p-CH 3 Ph); and R 1 is hydrogen, alkyl, haloalkyl, alkoxy, acetyl, or aryl.
Preferred species of hydrazonoyl derivative (A) with which to conduct the condensation reaction of the present invention are selected from those wherein W is halogen; X and Y are independently selected from hydrogen, chloro, or fluoro; Z is hydrogen, bromo, iodo, nitro, amino, or methylsulfonylamino; and R 1 is C 1 to C 12 alkyl.
More preferred species of hydrazonoyl derivative (A) are selected from those wherein W is chloro; X and Y are hydrogen; Z is hydrogen, 5-nitro, or 5-amino; and R 1 is methyl, ethyl, or propyl; wherein W is chloro; X is hydrogen; Y is 4-chloro; Z is hydrogen or 5-nitro; and R 1 is methyl, ethyl, or propyl; wherein W is chloro; X is 2-chloro or 2-fluoro; Y and Z are hydrogen; and R 1 is methyl, ethyl, or propyl; or wherein W is chloro; X is 2-chloro or 2-fluoro, Y is 4-chloro; Z is hydrogen 5-bromo, 5-iodo, or 5-nitro; and R 1 is methyl, ethyl, or propyl.
Most preferred species of hydrazonoyl derivative (A) are selected from those wherein W is chloro; X, Y, and Z are hydrogen; and R 1 is methyl, or wherein W is chloro; X is 2-fluoro; Y is 4-chloro, Z is hydrogen, and R 1 is methyl.
For conducting the condensation reaction of a hydrazonoyl derivative of formula (A), at least one organic solvent, such as those described above, is preferably employed. Preferred organic solvents are those that are low cost, best enhance the solubility of the starting materials to promote rate of reaction, and offer minimum solvent decomposition. Accordingly, preferred organic solvents include glymes, DMF, DMAC, 1-methyl-2-pyrrolidinone, and methyl sulfoxide. More preferred solvents are glymes, DMF, and DMAC. Particularly preferred solvents are DMAC and diglyme. A useful ratio of solvent to hydrozonoyl derivative (A) to afford optimum reaction conditions is in the range of about 2.5/1 to about 20/1 wt/wt, preferably about 3/1 to about 15/1.
Accordingly, when diglyme is the solvent of choice in which to conduct the condensation reaction of a hydrazonoyl derivative of formula (A), the rate of reaction benefits from the inclusion of a reaction rate-promoting amount of water. Inasmuch as the reaction proceeds in an acceptable manner without the presence of water, it is believed that it aids in dissolving the ring-forming agent thereby enhancing its contact with hydrazonoyl derivative (A) causing the reaction to proceed at a faster rate. The ratio of reaction rate-promoting amount of water to solvent as used in the present invention is in the range of about 0.001/1 to about 1/1 wt/wt. A preferred ratio is about 0.01/1 to about 0.9/1, more preferably about 0.04/1 to about 0.8/1.
In order to form a compound of formula I, a hydrazonoyl derivative of formula (A) is condensed with at least one ring-forming agent. Useful ring-forming agents in the process of the present invention include, for example, such as, without limitation sodium cyanate, potassium cyanate, silver cyanate, methyl carbamate, ethyl carbamate, phenyl carbamate, cyanic acid, isocyanic acid, acetyl isocyanate, and trimethylsilyl isocyanate. Preferred ring-forming agents are sodium cyanate, potassium cyanate, cyanic acid, isocyanic acid, and phenyl carbamate. More preferred ring-forming agents are sodium cyanate and potassium cyanate, particularly potassium cyanate. A useful mole ratio of ring-forming agent to hydrazonoyl derivative (A) of about 1/1 to about 5/1, preferably about 1.05/1 to about 2/1, and more preferably about 1.1/1 to about 1.3/1.
Preferably, the condensation reaction of a hydrazonoyl derivative of formula (A) to form a compound of formula I is conducted in the presence of a catalyst. Accordingly, useful catalysts, such as those described above, for condensing hydrazonoyl derivative (A) include potassium iodide, potassium fluoride, silver bromide, silver iodide, and elemental iodine. Preferred catalysts are potassium iodide, potassium fluoride, and elemental iodine, particularly potassium fluoride. The catalyst used in the present invention can be present in a mole ratio of catalyst to hydrazonoyl derivative (A) in a range of about 0.001/1 to about 0.1/1, preferably about 0.004/1 to about 0.06/1. Additional amounts of catalyst may be added if necessary to drive the reaction faster, for example.
The temperature at which and the period for which a chemical reaction such as the condensation reaction of a hydrazonoyl derivative of formula (A) is conducted will vary, as discussed above. The condensing of hydrazonoyl derivative (A) as set forth herein is generally conducted at a temperature in the range of about −10° C. to about 160° C. for a period of time up to about 30 hours, preferably in the range of about 0° C. to about 100° C. for up to about 20 hours, more preferably up to about 20 hours.
Generally in a process of condensing a hydrazonoyl derivative of formula (A) to form a compound of formula (I), the free hydrazine (1) as described above, for example, 2,4-dichlorophenylhydrazine (1) is reacted with acetic anhydride at a temperature of about 10° C. in an appropriate solvent such as ethyl acetate, yielding the corresponding 1acetyl-2-(2,4-dichlorophenyl)hydrazine (2). The hydrazine (2) is then chlorinated with phosphorous oxychloride at a temperature of about 110° C. in an appropriate solvent such as toluene, yielding the hydrazonoyl derivative of formula (A), N-(2,4-dichlorophenyl)ethanehydrozonoyl chloride. The hydrozonoyl chloride (A) is condensed with a ring forming agent, for example, potassium cyanate at a temperature of about 40° C. to about 65° C. in an appropriate solvent such as DMAC, yielding the corresponding compound of formula (I), 45-dihydro-1-(2,4-dichlorophenyl)-3-methyl-1,2,4-triazol-5(1H)-one. The condensing of hydrozonoyl chloride (A) to the compound of formula (I) in solvents such as DMAC is routinely aided by the presence of a catalyst, such as potassium fluoride. A detailed procedure for the preparation, and the potassium fluoride-catalized condensing of the hydrozonoyl chloride (A) with the ring forming agent potassium cyanate in DMAC to yield a compound of formula (I) is set forth in Example 1 hereinbelow.
In a variation of the process of condensing a hydrazonoyl derivative of formula (A) to form a compound of formula (I), the hyrazonoyl derivative (A), for example, N-(2,4-dichlorophenyl)ethanehydrozonoyl chloride is conducted at ambient temperature in the solvent diglyme in the presence of a catalytic amount of water. A detailed procedure for the preparation, and the water-catalized condensing of the hydrozonoyl chloride (A) with the ring forming agent potassium cyanate in diglyme to yield a compound of formula (I) is set forth in Example 2 hereinbelow.
A third embodiment of the present invention relates to novel amidrazone and hydrazonoyl derivatives of formula (A) useful in the preparation of compounds of formula I. These compounds are represented-by formula (A):
wherein;
W is halogen, —NCO, —OSO 2 CH 3 , —OSO 2 CF 3 , —OSO 2 (p-CH 3 Ph); or —NHR where R is hydrogen, alkyl, or haloalkyl; X and Y are independently selected from hydrogen, halogen, nitro, and amino; Z is selected from hydrogen, halogen, alkyl, alkoxy, nitro, amino, or alkylsulfonylamino; and, R 1 is hydrogen, alkyl, haloalkyl, alkoxy, acetyl, or aryl.
Preferred novel compounds of formula (A) are those wherein W is halogen or —NHR where R is hydrogen or difluoromethyl; X and Y are independently selected from hydrogen, chloro, or fluoro; Z is hydrogen, bromo, iodo, nitro, amino, or methylsulfonylamino; and R 1 is C 1 to C 12 alkyl.
More preferred novel compounds of formula (A) are those wherein W is chloro or —NHR where R is hydrogen; X and Y are hydrogen; Z is hydrogen, 5-nitro, or 5-amino; and R 1 is methyl, ethyl, or propyl; those wherein W is chloro or —NHR where R is hydrogen; X is hydrogen, Y is 4-chloro, Z is hydrogen or 5-nitro; and R 1 is methyl, ethyl, or propyl; those wherein W is chloro or —NHR where R is hydrogen; X is 2-chloro or 2-fluoro; Y and Z are hydrogen; and R 1 is methyl, ethyl, or propyl; and, those wherein W is chloro or —NHR where R is hydrogen; X is 2-chloro or 2-fluoro, Y is 4-chloro; Z is hydrogen, 5-bromo, 5-iodo, or 5-nitro; and R 1 is methyl, ethyl, or propyl.
Most preferred compounds of formula ( A ) are those wherein W is chloro or —NHR where R is hydrogen, X, Y, and Z are hydrogen, and R 1 is methyl; or wherein W is chloro or —NHR where R is hydrogen, X is 2-fluoro, Y is 4-chloro, Z is hydrogen, and R 1 is methyl.
The process of the present invention is carried out in accordance with the procedures shown in the examples below. The examples serve only to illustrate the invention and should not be interpreted as limiting since further modifications of the disclosed invention will be apparent to those skilled in the art. All such modifications are deemed to be within the scope of the invention as defined in the claims.
EXAMPLE 1
This example illustrates a process for preparing 4,5-dihydro-1-(2,4-dichlorophenyl)-3-methyl-1,2,4-triazol-5(1H)-one (I) from N-(2,4-dichlorophenyl)ethanehydrazonoyl chloride (A) in DMAC solvent
A slurry of 101.4 grams (0.4751 mole) of 2,4-dichlorophenylhydrazine hydrochloride in 600 mL of water was stirred, and a solution of 20.9 grams (0.5225 mole) of sodium hydroxide in 100 mL of water was slowly added. During the addition, the reaction mixture thickened. An additional 50 mL of water was added. to aid fluidity. Upon completion of addition of the sodium hydroxide solution, an additional 70 mL of water was added. The reaction mixture was stirred for about 75 minutes, then it was extracted with three 300 mL portions of ethyl acetate. The extracts were combined and dried with magnesium sulfate. The mixture was filtered and the filtrate containing free 2,4-dichlorophenylhydrazine (1) was transferred to an appropriate reaction vessel. The stirred solution was cooled to about 10° C., and 58.2 grams (0.5701 mole) acetic anhydride was added dropwise. Upon completion of addition, gas chromatographic (GC) analysis of the reaction mixture indicated the reaction was about 99% complete. The cooling medium was removed, and a solution of 62.5 grams of potassium carbonate in 200 mL of water was added to the reaction mixture. The mixture was stirred for about five minutes and the organic layer was separated. The organic layer was concentrated under reduced pressure, yielding 102.0 grams (98% yield) of 1-acetyl-2-(2,4-dichlorophenyl)hydrazine (2).
A solution of 25.0 grams (0.1142 mole) of 1-acetyl-2-(2,4-dichlorophenyl)hydrazine (2) in 120 grams of toluene was stirred, and 17.7 grams (0.1142 mole) of phosphorus oxychloride was added portionwise. Upon completion of addition the reaction mixture was warmed to about 110° C. where it stirred for about 30 minutes. GC analysis of the reaction mixture after this time indicated the reaction was complete. An additional 100 grams of toluene was added to the reaction mixture, and the solution was decanted into a separatory funnel. A residue in the reaction vessel was washed with about 40 grams of toluene, and the wash was also decanted into the separatory funnel. The toluene solution was then washed with an aqueous solution of 10% potassium carbonate. The aqueous layer was back-washed with two 75 gram portions of toluene. The combined toluene layer and washes was dried with magnesium sulfate. The mixture was filtered and the filtrate was concentrated under reduced pressure, yielding 21.3 grams (78.5% yield) of N-(2,4-dichlorophenyl)ethanehydrazonoyl chloride (A).
A solution of 21.3 grams (0.0896 mole) of N-(2,4-dichlorophenyl)ethanehydrazonoyl chloride (A) in 500 grams of N,N-dimethylacetamide (DMAC) was stirred and 9.1 grams (0.1127 mole) of potassium cyanate, followed by 0.1 gram (0.0018 mole) of potassium fluoride were added. Upon completion of addition, the heat of reaction caused the reaction mixture temperature to rise to about 60° C. The reaction mixture was stirred for 30 minutes during which time the reaction mixture temperature fell to about 45° C. GC analysis of the reaction mixture after this time indicated that the reaction was complete. The reaction mixture was concentrated under reduced pressure to a residue. The residue was slurried with about 100 grams of water, and the resultant solid was collected by filtration. The solid was washed with water and dried, yielding 21.2 grams of subject compound (I) (yield from (2) was 77.3%; yield from (A) was 96.8%).
EXAMPLE 2
This example illustrates a process for preparing 4,5-dihydro-1-(2,4-dichlorophenyl)-3-methyl-1,2,4-triazol-5(1H)-one (I) from N-(2,4-dichlorophenyl)ethanehydrazonoyl chloride (A) in diglyme solvent
A solution of 5.1 grams (0.0214 mole) of N-(2,4-dichlorophenyl)ethanehydrazonoyl chloride (A), prepared as in Example 1, 2.1 grams (0.0257 mole) potassium cyanate, and 3 mL of water in 51 mL of diglyme was stirred at ambient temperature for about 22 hours. After this time, the reaction mixture was concentrated under reduced pressure to a residue. The residue was dissolved in about 500 mL of ethyl acetate and washed with three 25 mL portions of water. The organic layer was dried with magnesium sulfate and filtered. The filtrate was concentrated under reduced pressure to a residue. The residue was triturated with hexane and the resultant solid was collected by filtration. The solid was dried, yielding 4.5 grams (85.2% yield from (A)) of subject compound (I).
EXAMPLE 3
This example illustrates a process for preparing 4,5-dihydro-1-(2,4-dichlorophenyl)-3-methyl-1,2,4-triazol-5(1H)-one (I) from 2-(2,4-dichlorophenyl)hydrazidethaneimidic acid (A)
A stirred solution of 13.6 grams (0.1100 mole) of ethyl acetimidate hydrochloride and 13.2 grams (0.1300 mole) of triethylamine in 100 grams of methylene chloride was cooled to about 0° C. for five minutes, and 17.7 grams (0.1000 mole) of 2,4-dichlorophenylhydrazine (1) was added. Upon completion of addition the reaction mixture stirred at 0° C. for about one hour, then it was allowed to warm to ambient temperature where it stirred for about two hours. GC analysis of the reaction mixture indicated the presence of a small amount of unreacted (1). An additional 0.6 gram of ethyl acetimidate hydrochloride was added (total 14.2 gram—0.1150 mole), and the reaction mixture was stirred for an additional one hour. After this time the reaction mixture was washed with about 20 mL of water and dried with magnesium sulfate. The mixture was filtered, and the filtrate was concentrated under reduced pressure to a semi-solid residue. The residue was triturated with 20 mL of hexane, and the resultant solid was collected by filtration. The solid was washed with 50 mL of hexane and dried, yielding 20.4 grams (93.4% yield) of 2-(2,4-dichlorophenyl)hydrazidethaneimidic acid (A).
A stirred solution of 7.5 grams (0.0344 mole) of 2-(2,4-dichlorophenyl)hydrazidethaneimidic acid (A), 7.4 grams (0.0344 mole) of diphenyl carbonate, and 0.2 gram (0.0017 mole) of 4-dimethylaminopyridine (DMAP) in 20 grams of toluene was heated at reflux for about 30 minutes. GC analysis of the reaction mixture after this time indicated the presence of unreacted diphenyl carbonate. An additional 0.3 gram of (A) was added (total 7.8 grams—0.0358 mole), and the reaction mixture was heated at reflux for an additional 30 minutes. After this time the reaction mixture was cooled and concentrated under reduced pressure to a residue. The residue was slurried for about two hours in refluxing hexane, then it was collected by filtration, yielding about 8.1 grams of subject compound (I) (yield from (A) is 93.2%; yield from (1) is 87.0%).
While this invention has been described with an emphasis upon preferred embodiments, it will be obvious to those of ordinary skill in the art that variations of the preferred embodiments may be used and that it is intended that the invention may be practiced otherwise than as specifically described herein. Accordingly this invention includes all modifications encompassed within the spirit and scope as defined by the following claims.
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A process is described for preparing 1-aryltriazolinones of formula I useful in the production of commercial herbicides:
by (i) carbonylating an amidrazone of formula (A) with one or more carbonylating agent, or by (ii) condensing a hydrazonoyl derivative of formula (A) with one or more ring-forming agent, wherein formula (A) is
where W, X, Y, Z, and R 1 are fully described herein. Preferred are those where W is halogen or —NHR where R is hydrogen or haloalkyl; X and Y are independently selected from hydrogen, chloro, or fluoro; Z is hydrogen, bromo, iodo, nitro, amino, or methylsulfonylamino; and R 1 is methyl. Certain compounds of formula (A) are novel compositions of matter. The process as described herein has utility in providing compounds of formula I in unexpectedly high yield and purity.
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This application claims the benefit of U.S. Provisional Application No. 60/676,857, filed May 2, 2005.
BACKGROUND
Fibrous glass insulation (“fiberglass” or “glass fiber” insulation) products generally comprise matted glass fibers bonded together by a binder that is often a cured thermoset polymeric material. Molten streams of glass are drawn into fibers of random lengths and blown into a forming chamber where they are randomly deposited as a mat onto a traveling conveyor. The fibers, while in transit in the forming chamber, and while often still hot from the drawing operation are sprayed with the binder. The coated fibrous mat is transferred to a curing oven where heated air, for example, is blown through the mat to cure the binder and rigidly bond the glass fibers together.
Fiberglass binders have a variety of uses ranging from stiffening applications where the binder is applied to woven or non-woven fiberglass sheet goods and cured, producing a stiffer product; thermo-forming applications wherein the binder resin is applied to sheet or lofty fibrous product following which it is dried and optionally B-staged to form an intermediate but yet curable product; and to fully cured systems such as building insulation.
Binders useful in fiberglass insulation products generally require a low viscosity in the uncured state, yet characteristics so as to form a rigid thermoset polymeric mat for the glass fibers when cured. A binder which forms a rigid matrix when cured is required so that a finished fiberglass thermal insulation product, when compressed for packaging and shipping, will recover to its specified vertical dimension when installed in a building.
From among the many thermosetting polymers, numerous candidates for suitable thermosetting fiber-glass binder resins exist. However, binder-coated fiberglass products are often of the commodity type, and thus cost becomes a driving factor, generally ruling out such resins as thermosetting polyurethanes, epoxies, and others. Due to their excellent cost/performance ratio, the resins of choice in the past have been phenol/formaldehyde resins. Phenol/formaldehyde resins can be economically produced, and can be extended with urea prior to use as a binder in many applications. Such urea-extended phenol/formaldehyde binders have been the mainstay of the fiberglass insulation industry for years.
Over the past several decades, however, minimization of volatile organic compound emissions (VOCs) both on the part of the industry desiring to provide a cleaner environment, as well as by Federal regulation, has led to extensive investigations into not only reducing emissions from the current formaldehyde-based binders, but also reducing the amount of binder used in production. Increasing stringent Federal regulations has lead to greater attention to alternative binder systems which are free from formaldehyde.
One particularly useful formaldehyde-free binder system employs a binder comprising a polycarboxy polymer and a polyol. Formaldehyde-free resins are those which are not made with formaldehyde or formaldehyde-generating compounds. Formaldehyde-free resins, such as acrylic resins, do not emit appreciable levels of formaldehyde during the insulation manufacturing process and do not emit formaldehyde under normal service conditions. Use of this binder system in conjunction with a catalyst, such as an alkaline metal salt of a phosphorous-containing organic acid, results in glass fiber products that exhibit excellent recovery and rigidity properties.
Fiberglass products, such as fiberglass insulation, are exposed to a variety of environmental conditions that can adversely affect the performance of the product. Overall rigidity and recovery of the product are typical measures of performance.
Curing of the fiberglass products is essential to proper product performance. Factors that contribute to the curing process, and the ultimate performance of the fiberglass product, include many variables, and ultimate product performance is often unpredictable.
There is a need for reducing the quantity of acrylic resin used in binder systems during the manufacture of fiber glass insulation products without negatively impacting the curing process or the overall performance of the product.
The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.
SUMMARY
The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools, and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other improvements.
The method provides for reducing the amount of acrylic binder or resin used in glass fiber manufacturing while maintaining product performance. One method for reducing the amount of acrylic resin used in glass fiber manufacturing maximizes ramp moisture, operating between 5 and 20 percent. In an exemplary embodiment, the ramp moisture is maintained between 5 and 10 percent. Another method for reducing the amount of acrylic resin used in glass fiber manufacturing maximizes the use of silane, operating between 0.019% and 0.350% solid per weight of glass (between 0.20% and 3.64% per weight resin solids). In exemplary embodiments, the organosilane can be provided in an amount between 0.5% and 3.0% by weight of resin solids, or between 1.5% and 2.3% by weight of resin solids. Most preferably, a method for reducing the amount of acrylic resin used in glass fiber manufacturing maximizes the use of silane, operating between 0.70% and 0.26% solid per weight of glass (between 0.8% and 2.7% per weight resin solids). Increasing ramp moisture and increasing silane levels in the binder were discovered to reduce the amount of acrylic-based binder required to manufacture glass fiber material while maintaining or improving product performance. Relatedly, increasing either ramp moisture or silane levels were discovered to reduce the amount of acrylic-based binder required to produce glass fiber material while maintaining product performance.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the methods and compositions disclosed herein will be described hereinafter which form the subject of the claims of the invention. It should be appreciated that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the methods and compositions disclosed herein. It should also be realized that such equivalent constructions do not depart from the methods and compositions disclosed herein. The novel features which are believed to be characteristic of the methods and compositions disclosed herein, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description.
In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and tables and by study of the following descriptions.
BRIEF DESCRIPTION OF THE DRAWINGS
Exemplary embodiments are illustrated in the referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than limiting.
FIG. 1 is an analysis of variance representing measurements of the rigidity of a product manufactured according to a method disclosed herein.
FIG. 2 is a reduced model for rigidity measurements of a product manufactured according to a method disclosed herein. The response surface regression of FIG. 2 plots QKdrp vs. ramp moisture, resin flow, and silane flow.
FIG. 3A is a contour plot of product rigidity for resin flow (y-axis) (L/min) vs. ramp moisture x-axis) (%).
FIG. 3B is a contour plot of product rigidity for silane flow (y-axis) (L/min) vs. ramp moisture x-axis) (%).
FIG. 3C is a contour plot of product rigidity for silane flow (y-axis) (L/min) vs. resin flow (y-axis) (L/min).
FIG. 4 is an analysis of variance for product rigidity following seven (7) days of aging at 90° F. and 90% humidity.
FIG. 5A is a contour plot of product rigidity following seven (7) days of aging at 90° F. and 90% humidity for resin flow (y-axis) (L/min) vs. ramp moisture x-axis) (%).
FIG. 5B is a contour plot of product rigidity following seven (7) days of aging at 90° F. and 90% humidity for silane flow (y-axis) (L/min) vs. ramp moisture x-axis) (%).
FIG. 5C is a contour plot of product rigidity following seven (7) days of aging at 90° F. and 90% humidity for silane flow (y-axis) (L/min) vs. resin flow (y-axis) (L/min).
DETAILED DESCRIPTION
It has been discovered that fiber glass insulation product properties may be improved or maintained when manufactured under conditions of increased overall ramp moisture and/or increased silane content, while reducing amounts of resin or binder. The improvement in rigidity after aging of the fiber glass insulation product manufactured with increased silane flow as described herein was unexpected.
Structural integrity and physical properties of glass fiber products overall are related to, amongst other things, curing of binders or resins which hold the glass fibers together and provide stiffness and resiliency to the products. The effectiveness of the binder composition is due in large measure to how well the binder is cured. This is particularly true for novel formaldehyde-free binder compositions that are currently being used by fiberglass manufacturers. Physical properties of manufactured glass fiber products are dependant upon, amongst other things, the temperature of the binder resin during the curing step, the length of time that the temperature is maintained, and the silane content of the binder.
The methods and compositions described herein are particularly useful for ensuring that properties of manufactured glass fiber products are maintained or improved when using formaldehyde-free binders, including, but not limited to, acrylic thermoset binders, while reducing the amount of binder used in the manufacturing process. The formaldehyde-free binders useful in the practice of the methods and compositions disclosed herein are typically prepared from resins comprising poly-carboxy polymers such as acrylic resins, although other formaldehyde-free resins may be employed. As used herein, the term “formaldehyde-free” or “FF” means that the resin or binder composition is substantially free of formaldehyde and/or does not liberate formaldehyde as a result of curing or drying. FF binders and resins generally have a molecular weight of less than about 10,000, preferably less than about 5,000.
In one embodiment, the polycarboxy polymer used in the formaldehyde-free binder comprises an organic polymer or oligomer containing more than one pendant carboxy group. The polycarboxy polymer may be a homopolymer or copolymer prepared from unsaturated carboxylic acids including, but not necessarily limited to, acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, maleic acid, cinnamic acid, 2-methylmaleic acid, itaconic acid, 2-methylitaeonic acid, α-β-methyleneglutaric acid, and the like. Alternatively, the polycarboxy polymer may be prepared from unsaturated anhydrides including, but not necessarily limited to, maleic anhydride, methacrylic anhydride, and the like, as well as mixtures thereof. Methods for polymerizing these acids and anhydrides are well-known in the chemical art.
In one embodiment, the formaldehyde-free curable aqueous binder composition also contains a polyol containing at least two hydroxyl groups. The polyol must be sufficiently nonvolatile such that it will substantially remain available for reaction with the polyacid in the composition during heating and curing operations. The polyol may be a compound with a molecular weight less than about 1000 bearing at least two hydroxyl groups such as, for example, ethylene glycol, glycerol, pentaerythritol, trimethylol propane, sorbitol, sucrose, glucose, resorcinol, catechol, pyrogallol, glycollated ureas, 1,4-cyclohexane diol, diethanolamine, triethanolamine, and certain reactive polyols such as, for example, β-hydroxyalkylamides such as, for example, bis[N,N-di(β-hydroxyethyl)]adipamide, as may be prepared according to the teachings of U.S. Pat. No. 4,076,917, incorporated herein by reference, or it may be an addition polymer containing at least two hydroxyl groups such as, for example, polyvinyl alcohol, partially hydrolyzed polyvinyl acetate, and homopolymers or copolymers of hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, and the like. The most preferred polyol for the purposes of the present invention is triethanolamine (TEA), or mixtures of DEA and TEA.
The ratio of the number of equivalents of carboxy, anhydride, or salts thereof of the polyacid to the number of equivalents of hydroxyl in the polyol is from about 1/0.01 to about 1/3. An excess of equivalents of carboxy, anhydride, or salts thereof of the polyacid to the equivalents of hydroxyl in the polyol is preferred. The more preferred ratio of the number of equivalents of carboxy, anhydride, or salts thereof in the polyacid to the number of equivalents of hydroxyl in the polyol is from about 1/0.4 to about 1/1. The most preferred ratio of the number of equivalents of carboxy, anhydride, or salts thereof in the polyacid to the number of equivalents of hydroxyl in the polyol is from about 1/0.6 to about 1/0.8, and most preferably from 1/0.65 to 1/0.75. A low ratio, approaching 0.7:1, has been found to be of particular advantage in the present invention, when combined with a low molecular weight polycarboxy polymer and the low pH binder.
The formaldehyde-free curable aqueous binder composition may also contain a catalyst, such as, for example, a phosphorous-containing accelerator which may be a compound with a molecular weight less than about 1000 such as, for example, an alkali metal polyphosphate, an alkali metal dihydrogen phosphate, a polyphosphoric acid, and an alkyl phosphinic acid or it may be an oligomer or polymer bearing phosphorous-containing groups such as, for example, addition polymers of acrylic and/or maleic acids formed in the presence of sodium hypophosphite, addition polymers prepared from ethylenically unsaturated monomers in the presence of phosphorous salt chain transfer agents or terminators, and addition polymers containing acid-functional monomer residues such as, for example, copolymerized phosphoethyl methacrylate, and like phosphonic acid esters, and copolymerized vinyl sulfonic acid monomers, and their salts. Such a phosphorous-containing accelerator may be used at a level of from about 1% to about 40%, by weight based on the combined weight of the polyacid and the polyol.
The binder compositions described herein are usually supplied as an aqueous suspension containing about 48 to 53 wt % solids and are prepared by first further diluting the binder to a point where the composition contains from about 1 to about 10 percent solids.
Acid is then added to the aqueous binder composition to reduce the pH to a less than about 3.5, preferably less than 3.0, much preferably less than 2.5. Low pH has been found to be important in ensuring proper application and curing of the binder composition.
Curing of the binders is most often accomplished by heating the binder coated fibers in a curing oven. Curing ovens typically are arranged with one or more temperature zones of varying ramp moistures. In each zone, the binder-coated fibers are subjected to a temperature in the range of 150° C. to 325° C. with from 180 to 250° C. preferred. Air is also forced through the fiberglass product by fans associated with each zone to ensure uniform heating of the fiberglass product.
Use of silane adhesion promoters often is utilized when employing a binder for a glass mat. Identifiying appropriate adhesion promoters for thermosetting acrylic resin-based binder compositions might also be helpful in delivering a more useful fiberglass binder. The presence of the ethoxysilane has been found to impart good hydrolytic stability to the binder, and hence the fiberglass mat to which the binder is applied. As well, the use of an ethoxysilane, as opposed to other silanes, avoids harmful emissions such as methanol, which is recognized as a HAP (hazardous air pollutant). As a result, fiberglass products such as insulation made with the binder of the methods and compositions disclosed herein provide a competitive advantage as the products will meet advertised thickness so as to make the required R value, and also have good recovery and rigidity properties, and good hydrolytic stability, and a reduction in the amount of resin or binder used in the manufacturing process. The use of various silanes as adhesion promoters in binders used in the production of glass fiber-based materials is discussed by Guy Clamen, et al., “Acrylic Thermosets: A Green Chemistry Alternative to Formaldehyde Resins,” International Nonwovens Technical Conference, Baltimore, Md., Sep. 15-18, 2003.
Silanes are monomeric silicon compounds with four substituent groups attached to the silicon atom and are commercially available from chemical companies such as Dow Corning and GE Silicones. Silane compounds are believed to act as an adhesion promoter of the binder to the fiberglass by a coupling mechanism. Silane reacts with the thermoset polycarboxy molecule and attaches to the glass fiber substrate. If an appropriate silane is chosen, it has been found that the properties of the polycarboxy based binder, and hence the fiberglass product, can be enhanced.
The silanes of the methods and compositions disclosed herein are ethoxysilanes. The ethoxysilanes generally do not contain a vinyl group, and preferably contain an epoxy or glycidoxy group. A mixture of ethoxysilanes can be employed. Among the most preferred ethoxysilanes are the diethoxysilanes such as, glycidoxy or epoxydiethoxysilane, and triethoxysilane, which have been found to provide good results when used in combination with a polycarboxy/polyol binder system. A polycarboxy based binder system containing an ethoxysilane also has the advantage of good hydrolytic stability under hot, humid conditions. Thus, the good physical performance of such binders can be realized regardless of the environmental conditions, which provides a real competitive advantage. The ethoxysilanes used in the binder compositions of the methods and compositions disclosed herein also result in no harmful emissions, as none of the emissions are considered a HAP (hazardous air pollutant). The combination of good physical properties and environmental acceptability offered by the use of ethoxysilanes in the binder compositions of the methods and compositions disclosed herein is truly advantageous to the industry. Further reducing the amount of binder composition used in the manufacturing process is also advantageous.
The formaldehyde-free curable aqueous binder composition may contain, in addition, conventional treatment components such as, for example, emulsifiers, pigments, filler, anti-migration aids, curing agents, coalescents, wetting agents, biocides, plasticizers, anti-foaming agents, colorants, waxes, and anti-oxidants.
The formaldehyde-free curable aqueous binder composition may be prepared by admixing the polyacid, the polyol, and the phosphorous-containing accelerator using conventional mixing techniques. In another embodiment, a carboxyl- or anhydride-containing addition polymer and a polyol may be present in the same addition polymer, which addition polymer would contain both carboxyl, anhydride, or salts thereof functionality and hydroxyl functionality. In another embodiment, the salts of the carboxy-group are salts of functional alkanolamines with at least two hydroxyl groups such as, for example, diethanolamine, triethanolamine, dipropanolamine, and di-isopropanolamine. In an additional embodiment, the polyol and the phosphorous-containing accelerator may be present in the same addition polymer, which addition polymer may be mixed with a polyacid. In yet another embodiment the carboxyl- or anhydride-containing addition polymer, the polyol, and the phosphorous-containing accelerator may be present in the same addition polymer. Other embodiments will be apparent to one skilled in the art. As disclosed herein-above, the carboxyl groups of the polyacid may be neutralized to an extent of less than about 35% with a fixed base before, during, or after the mixing to provide the aqueous composition. Neutralization may be partially effected during the formation of the polyacid.
Once the composition of the polyacid and the polyol has been prepared, the ethoxysilane can then be mixed in with or simply added to the composition to form the final binder composition to be sprayed on the fiberglass. The ethoxysilane is therefore basically an important additive to conventional polycarboxy binder systems, such as that described in U.S. Pat. No. 6,331,350, which is hereby expressly incorporated by reference in its entirety. As molten streams of glass are drawn into fibers of random lengths and blown into a forming chamber where they are randomly deposited as a mat onto a traveling conveyor, the fibers, while in transit in the forming chamber, are sprayed with the aqueous binder composition of the methods and compositions disclosed herein, which includes the ethoxysilane.
More particularly, in the preparation of fiberglass insulation products, the products can be prepared using conventional techniques. As is well known, a porous mat of fibrous glass can be produced by fiberizing molten glass and immediately forming a fibrous glass mat on a moving conveyor. The expanded mat is then conveyed to and through a curing oven wherein heated air is passed through the mat to cure the resin. The mat is slightly compressed to give the finished product a predetermined thickness and surface finish. Typically, the curing oven is operated at a temperature from about 150° C. to about 325° C. Preferably, the temperature ranges from about 180 to about 225° C. Generally, the mat resides within the oven for a period of time from about ½ minute to about 3 minutes. For the manufacture of conventional thermal or acoustical insulation products, the time ranges from about ¾ minute to about 2 minutes. The fibrous glass having a cured, rigid binder matrix emerges from the oven in the form of a bat or roll which may be compressed for packaging and shipping and which will thereafter substantially recover its thickness when unconstrained.
The formaldehyde-free curable aqueous composition may also be applied to an already formed nonwoven by conventional techniques such as, for example, air or airless spraying, padding, saturating, roll coating, curtain coating, beater deposition, coagulation, or the like.
The waterborne formaldehyde-free silane-containing composition, after it is applied to a nonwoven, is heated to effect drying and curing. The duration and temperature of heating will affect the rate of drying, ramp moisture, processability and handleability, and property development of the treated substrate. Heat treatment at about 120° C., to about 400° C., for a period of time between about 3 seconds to about 15 minutes may be carried out; treatment at about 150° C., to about 250° C., is preferred. The drying and curing functions may be effected in two or more distinct steps, if desired. For example, the composition may be first heated at a temperature and for a time sufficient to substantially dry but not to substantially cure the composition and then heated for a second time at a higher temperature and/or for a longer period of time to effect curing. Such a procedure, referred to as “B-staging,” may be used to provide binder-treated nonwoven, for example, in roll form, which may at a later stage be cured, with or without forming or molding into a particular configuration, concurrent with the curing process.
The heat-resistant nonwovens may be used for applications such as, for example, insulation batts or rolls, as reinforcing mat for roofing or flooring applications, as roving, as microglass-based substrate for printed circuit boards or battery separators, as filter stock, as tape stock, as tape board for office partitions, in duct liners or duct board, and as reinforcement scrim in cementitious and non-cementitious coatings for masonry. Due to the good hydrolytic stability of the binders and good humid aging performance, products prepared using the methods disclosed herein can be used under varying environmental conditions.
Measurement of rigidity generally involves preparing a specimen of fiberglass product for testing, placing the specimen in contact with water and determining the water resistance of the specimen. The water resistance can be determined by either qualitative or quantitative techniques. Measurement of rigidity can be used to evaluate the water resistance of fiberglass products where its ability to resist water affects the products performance. Methods for evaluating the water resistance of binder-coated fiberglass products are disclosed in co-pending U.S. application Ser. No. 10/887,023, filed by Ward Hobert et al., on Jul. 9, 2004, and incorporated by reference herein in its entirety.
We conclude that resin usage can be reduced in a Manufacturing process that increases silane and/or ramp moisture. These increases in ramp moisture and/or silane flow will enable reduced costs in a fiberglass manufacturing system. It is important to note that the effect of silane is improved product durability. It is possible to reduce resin usage significantly while maintaining equal or improved product performance. By maximizing ramp moisture, operating between 5 and 20 percent, we can reduce resin usage while improving product performance. By maximizing the use of silane, operating between 0.019% and 0.350% solid per weight of glass (between 0.20% and 3.64% per weight resin solids), and most preferably, between 0.70% and 0.26% solid per weight of glass (between 0.8% and 2.7% per weight resin solids), we can reduce the amount of acrylic resin used in glass fiber manufacturing while maintaining or improving product performance.
EXAMPLES
The following is offered as an example of the invention and should not be construed as limiting the invention.
Through the use of a designed experiment and subsequent product aging and testing, an opportunity was observed that will reduce resin system cost in plants operating on the acrylic resin systems. Based upon the product rigidity measurements for both quick (in-plant) and following 7 days of aging at 90° F. and 90% humidity, increases in ramp moisture and/or silane usage provided an opportunity to reduce resin usage and therefore product cost. Product recovery met or exceeded label thickness throughout the trial for both the quick and aged products and was not found to be significant to any of the process variables manipulated.
Trials were performed at one or more manufacturing plant with a design to improve the cost and performance of insulation products manufactured with formaldehyde-free binders. The trials disclosed herein focused on three (3) factors identified as having the significance to product performance. Manipulation of ramp moisture, resin flow and silane flow were investigated using a central-composite designed experiment. During the execution of the trial the product performance varied significantly with the process adjustments. FIG. 1 represents an analysis of variance (“ANOVA”) of the quick rigidity measurements by run.
As observed in the ANOVA results, there were significant differences between product runs. Also, runs 2 and 15 were center points for the experiment and are statistically identical suggesting no drifting occurred during the 8 hour trial. Analysis of the experiment suggested that three factors (ramp moisture, silane flow, and resin flow) were significant to product performance. A reduced model of quick rigidity is presented in FIG. 2 . The analysis suggests that all three factors are significant to quick rigidity. FIG. 3 represents a contour plot of quick rigidity for each of the three combinations of factors.
Interpretation of FIG. 3 leads to a conclusion that increased ramp moisture and/or silane flow will allow for reductions in resin flow while maintaining acceptable product performance. The results of the trials suggest that there is opportunity to reduce resin usage provided that silane levels are increased while maintaining or increasing ramp moisture. The reduced model depicted in FIG. 3 , and shown in FIG. 2 , predicted product rigidity with and RSQ of 90.8%.
Similar to the quick product performance analysis, an ANOVA was performed for rigidity following 7 days of sag room aging. FIG. 4 represents the output for the ANOVA performed on product aged 7 days at 90° F. and 90% humidity. As was observed in the quick product performance, the product aged 7 days also showed significant differences based on the process settings. Also, similar to the quick performance, runs 2 and 15 were statistically the same suggesting a minimum amount of process drift occurred during the 8-hour trial. Recovery for the products at both quick and 7 days of sag room aging met or exceeded label thickness and were not found to be significant to any of the factors manipulated in the experiment.
Following the ANOVA analysis shown in FIG. 4 , analysis of the experiment was performed. FIG. 5 represents a contour plot for the reduced model. As with quick rigidity, all factors were significant to product performance following 7 days at 90° F. and 90% humidity.
Through interpretation of FIG. 5 , we conclude that resin usage can be reduced in a manufacturing process that increases silane flow and/or ramp moisture. These increases in ramp moisture and/or silane flow will enable a reduced manufacturing system cost. It is important to note that the effect of silane is improved product durability when reduced amounts of acrylic-based binder are used.
Through the analysis of the responses displayed above, we conclude that it is possible to reduce resin usage significantly while maintaining equal or improved product performance. By maximizing ramp moisture, operating between 5 and 20 percent we can reduce resin usage while improving product performance. By maximizing the use of silane, operating between 0.019% and 0.350% solid per weight of glass (between 0.20% and 3.64% per weight resin solids), and most preferably, between 0.70% and 0.26% solid per weight of glass (between 0.8% and 2.7% per weight resin solids), we can reduce the amount of acrylic resin used in glass fiber manufacturing by up to 30% while maintaining or improving product performance.
While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions, and subcombinations thereof. It is therefore intended that claims hereafter introduced are interpreted to include all such modifications, permutations, additions, and sub-combinations as are within their spirit and scope.
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A method for reducing the amount of binder or resin used in glass fiber manufacturing while maintaining product performance is disclosed. The method generally reduces the amount of binder or resin used in a manufacturing process by adjusting other factors in the manufacturing process. Specifically, ramp moisture and/or silane content are factors that are adjusted to achieve the results of the disclosed method. Additionally, glass fiber compositions resulting from the method are disclosed.
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BACKGROUND OF THE INVENTION
[0001] I. Field of the Invention
[0002] The present invention relates to prioritization systems and methods. More particularly, the invention relates to systems and methods for prioritizing customer inquiries.
[0003] II. Background and Material Information
[0004] Marketing products and services to customers, including, for example, cellular service plans involves several steps. Among other things, a marketer must first target the right demographic with the right message about a product using the right medium. For example, television advertisements may be aired at specific times based on the belief that a specific segment of the population may be watching. Second, having generated an interest in the marketed product, the marketer must then be able to respond to customer inquires about that product.
[0005] Typically, a marketer may staff a customer contact center for handling customer inquiries related to a marketed product. Because of high staffing expenses associated with such centers, it is typically not economical to provide enough staff such that all incoming calls are answered immediately. Indeed, there may be spikes in the number of incoming calls. This dynamic is especially problematic with certain advertising channels. Real time media channels such as television create large spikes in call volume immediately after an advertisement promoting a product has just aired. Anticipating such spikes and staffing the contact center accordingly is difficult because of constraints on allocation and distribution of human capital. This situation typically results in a significant number of abandoned calls, i.e., calls which are abandoned by the callers because of long wait times to reach a customer representative.
[0006] When callers who are more likely to purchase the offered product abandon their calls, the marketer loses revenue. In sum, the marketer's goal is not necessarily to serve all callers, but is to serve those callers who are most likely and able to purchase the product or service at issue.
[0007] In view of the foregoing, there is presently a need for a system and method for prioritizing customer inquires to a customer contact center.
SUMMARY OF THE INVENTION
[0008] Systems and methods consistent with the present invention maximize revenue at call centers by assigning higher priority, and thus reducing the wait time for those callers more likely to purchase an offered product or service.
[0009] Specifically, according to one aspect of the invention, a method for prioritizing a customer inquiry is provided. The method receives an inquiry from a customer. The method further prompts the customer to provide at least one of an identification number or customer information in response to a predetermined set of queries. The method further retrieves customer information about the customer based on the provided identification number. The method further computes a customer prioritization score based on the retrieved customer information. And the method prioritizes the customer inquiry based on the computed customer prioritization score.
[0010] According to another aspect of the invention, another method for prioritizing a customer inquiry is provided. The method receives an inquiry from a customer. The method prompts the customer to provide at least one of identification number or customer information in response to a predetermined set of queries. The method, when the customer provides customer information in response to the predetermined set of queries, computes a customer prioritization score based on the customer responses. And the method prioritizes the customer inquiry based on the computed customer prioritization score.
[0011] According to another aspect of the invention, a system for prioritizing a customer inquiry is provided. The system includes means for receiving an inquiry from a customer. The system further includes means for prompting the customer to provide at least one of an identification number or customer information in response to a predetermined set of queries. The system further includes, when the customer provides the identification number, means for retrieving customer information about the customer based on the provided identification number. The system further involves means for computing a customer prioritization score based on the retrieved customer information. And the system includes means for prioritizing the customer inquiry based on the computed customer prioritization score.
[0012] According to yet another aspect of the invention, a system for prioritizing a customer inquiry is provided. The system includes means for receiving an inquiry from a customer. The system further includes means for prompting the customer to provide at least one of an identification number or customer information in response to a predetermined set of queries. The system further includes, when the customer provides customer information in response to the predetermined set of queries, means for computing a customer prioritization score based on the customer responses. And the system includes means for prioritizing the customer inquiry based on the computed customer prioritization score.
[0013] Both the foregoing general description and the following detailed description are exemplary and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various embodiments and aspects of the present invention and, together with the description, explain the principles of the invention. In the drawings:
[0015] [0015]FIG. 1 illustrates an exemplary system environment in which the features of the present invention may be implemented;
[0016] [0016]FIG. 2 depicts an exemplary system consistent with the present invention; and
[0017] [0017]FIG. 3 is an exemplary flowchart of a process for prioritizing an inquiry from a customer consistent with the present invention.
DETAILED DESCRIPTION
[0018] Systems and methods consistent with the present invention solve the problems associated with lost revenue at customer contact centers when qualified and interested customers abandon calls. In particular, the system prioritizes customer inquiries to maximize revenue.
[0019] Upon receiving a customer inquiry, the system prompts the customer to respond to one or more prioritization queries. From the received responses, the system calculates a prioritization score describing further, the customer's likelihood to make a purchase and/or an expected value of any purchases. The system then prioritizes the customer's inquiry based on the calculated score. Alternatively, a customer may be prompted to enter an identification number. From this number, the system can access customer information used to determine a prioritization score for prioritizing the inquiry. In this way, the system maximizes revenue to the underlying business by assigning a higher priority to those customers likely to generate revenue.
[0020] The features of the present invention may be implemented in various system or network environments to provide automated computational tools to facilitate prioritization of a customer inquiry. Such environments and applications may be specially constructed for performing the various processes and operations of the invention or they may include a general-purpose computer or computing platform selectively activated or reconfigured by program code to provide the necessary functionality. The processes disclosed herein are not inherently related to any particular computer or other apparatus, and may be implemented by a suitable combination of hardware, software, and/or firmware. For example, various general-purpose machines may be used with programs written in accordance with teachings of the invention, or it may be more convenient to construct a specialized apparatus or system to perform the required methods and techniques. The present invention also relates to computer readable media that include program instruction or program code for performing various computer-implemented operations based on the methods and processes of the invention. The media and program instructions may be those specially designed and constructed for the purposes of the invention, or they may be of the kind well known and available to those having skill in the computer software arts. Examples of program instructions include both machine code, such as produced by compiler, and files containing a high level code that can be executed by the computer using an interpreter.
[0021] By way of a non-limiting example, FIG. 1 illustrates a system environment 50 in which the features and principles of the present invention may be implemented. As illustrated in the block diagram of FIG. 1, system environment 50 includes a computing platform 300 , a voice response unit 400 , a database 500 , which are connected via communications network 600 to customers, such as customer 1 810 , customer 2 820 , . . . customer n 860 . Customers may use system environment 50 to call a particular telephone number or a similar service.
[0022] Computing platform 300 is adapted to provide the necessary functionality and computing capabilities to prioritize a customer inquiry received at a contact center. Computing platform 300 is connected to voice response unit 400 to receive information entered by the customer upon being prompted by the voice response unit. Computing platform 300 is also operatively connected to database 500 for retrieving information from database 500 .
[0023] In the embodiment of FIG. 1, computing platform 300 preferably comprises a PC or mainframe computer for performing various functions and operations of the invention. Computing platform 300 may be implemented, for example, by a general purpose computer selectively activated or reconfigured by a computer program stored in the computer, or may be a specially constructed computing platform for carrying-out the features and operations of the present invention. Computing platform 300 may also be implemented or provided with a wide variety of components or subsystems including, for example, one or more of the following: a central processing unit, a co-processor, memory, registers, and/or other data processing devices and subsystems.
[0024] Voice response unit 400 may be implemented using, for example, a voice response unit available from Aspect Telecommunications, Corp. of San Jose, California. One skilled in the art will appreciate that voice response units made by other manufacturers may be used consistent with the present invention. In addition, call routing and prioritization functionality may be incorporated into the communications network 600 through the use of call routing software designed to provide such functions. One example is the Geotel software program available from Cisco Systems Inc. of San Jose, Calif.
[0025] As indicated above, computing platform 300 communicates with customers 810 , 820 , . . . 860 through voice response unit 400 , which in turn communicates with customers through communications network 600 . Communications network 600 may comprise, alone or in any suitable combination, a telephony-based network (such as a PBX or POTS), a local area network (LAN), a wide area network (WAN), a dedicated intranet, and/or the Internet. Further, any suitable combination of wired and/or wireless components and systems may be incorporated into communications network 600 .
[0026] Computing platform 300 also communicates with voice response unit 400 and database 500 through the use of direct connections or communication links, as illustrated in FIG. 1. Alternatively, communication between computing platform 300 and voice response unit 400 , and communication between computing platform 300 and database 500 may be achieved through the use of a network architecture (not shown) similar to that described above for communications network 400 . By using dedicated communication links or shared network architecture, computing platform 300 may be located in the same location or at a geographically distant location from voice response unit 400 and/or database 500 .
[0027] [0027]FIG. 2 depicts an exemplary system consistent with the present invention. As shown in FIG. 2, computing platform 300 may include a CPU 310 , a memory 320 , a display 330 , and I/O devices 340 . Memory 320 further includes customer prioritization program 350 , which when executed by CPU 310 provides a part of the prioritization functionality associated with the present invention. FIG. 2 further depicts database 500 , which is connected to the various components of the computing platform 300 and may be stored on a storage device, such as a hard disk. Database 500 includes customer-product information 510 , prioritization information 520 , and customer prioritization scores 530 . Customer-product information 510 may include financial information concerning potential customers, such as credit related information. Customer-product information 510 may also include other information that helps the system in prioritizing the calls to generate the highest net present value, for example. Net present value may be based on two factors: customer likelihood to purchase, and expected value of purchase, when a purchase is made. Thus, for example, customer-product information 510 may include information on indicators of ability to purchase, such as credit scores and other financial attributes, such as annual income levels. Customer-product information 510 may also include product-defined attributes, such as a product requiring a credit card as the only means of payment. Customer-product information 510 may also include customer predisposition to purchase based on factors such as offer solicited, marketing channel utilized, and previous history of purchases and/or inquiries. Prioritization information 520 may include pre-computed prioritization scores for customers, who may have been solicited in the past. Customer prioritization scores 530 may include scores for customers that are computed based on their responses to queries from the voice response unit.
[0028] [0028]FIG. 3 depicts exemplary flowchart of a process for prioritizing a call consistent with the present invention. When a customer makes an inquiry, the inquiry is received by voice response unit 400 (S. 10 ). One of ordinary skill in the art will appreciate that the inquiry from the customer may be received via a landline or a wireless connection. In addition, the customer inquiry may be a conventional telephone call or may be a call through the Internet, for example, using any of the voice over IP techniques.
[0029] Upon receipt of the inquiry, voice response unit 400 may attach a time-stamp to the customer inquiry to record the arrival time of the inquiry (S. 20 ). Next, the customer may be prompted for an identification number (S. 30 ). The identification number may be a solicitation number that may have been attached, for example, to a solicitation letter sent to the customer. One skilled in the art will appreciate that any identification code for identifying the customer may be used, such as a driver's license number, telephone number or a social security number. One skilled in the art will also appreciate that using technology, such as caller ID, the identification number may be obtained automatically and thereby obviate the need for requesting the identification number.
[0030] Next, computing platform 300 , alone or in combination with voice response unit 400 , determines whether an identification number was entered (S. 40 ). If an identification number was entered by the customer, then computing platform 300 retrieves customer information associated with the identification number (S. 50 ). Customer information associated with the customer may include prioritization information 520 and customer-product information 510 stored in database 500 , as shown in FIG. 2. Prioritization information 520 may further include pre-determined customer prioritization scores for those customers to whom a solicitation letter was sent, for example. Customer prioritizations scores may be determined, as described in more detail below, by analyzing each customer's likelihood to purchase a product and the expected value of such a product.
[0031] One skilled in the art will recognize that there are numerous methods for calculating customer prioritization scores using the information stored in database 500 , for example. The proper prioritization scheme to apply in any given application is determined by the overall business objective of the customer contact center. For example, computing platform 300 may prioritize customer inquiries based on which calls are likely to generate the highest net present value for the business. Net present value may be based on two factors: customer likelihood to purchase, and an expected value of a purchase. A customer's likelihood to make a purchase may, in turn, be determined from the customer's ability and predisposition to make a purchase. Indicators of ability to purchase include, but are not limited to, credit scores and other financial information, product-defined attributes such as a product requiring a credit card as the only means of payment and responses to queries. In addition, consumer predisposition to purchase may be indicated by the offer solicited, the marketing channel utilized, or by the previous history of purchases or inquiries. Finally, the expected value of a purchase may be determined based on the product offered and the expected needs of the consumer. Various forms of logical, numerical, or statistical techniques may then be used to model the likelihood to purchase and the expected value of the purchase based on the above criteria.
[0032] As part of this process, computing platform 300 may review a credit profile associated with the caller, stored in database 500 , and determine whether the caller has good credit. One skilled in the art will appreciate that database 500 may store summarized credit profiles of customers in order to reduce processing time. Other prioritization information may relate to whether the customer has a checking account or not. One skilled in the art will appreciate that as part of this step, computing platform 300 may obtain additional information, as necessary, from other sources of information, such as financial clearing houses, via communications network 600 .
[0033] Next, computing platform 300 computes a customer prioritization score based on the customer information, if a predetermined score for the customer is not found in prioritization information 520 , stored in database 500 (S. 60 ), then a new customer prioritization score is computed. Computing platform 300 may compute the customer prioritization score using several techniques. In one implementation, for example, a table stored in database 500 may include predetermined scores, each associated with various factors describing a customer's likelihood to purchase and an expected value of a purchase. For example, the table may define a prioritization score for a customer who owns a credit card and wishes to purchase a cellular service plan. One skilled in the art will appreciate that other known statistical and numerical modeling techniques may be used to accomplish this step including regression analyses, Boolean logic, statistical hypothesis testing logic, or decision trees. Upon receiving the customer information, computing platform 300 then searches for the table entries corresponding to each of the various factors describing the customer's likelihood to purchase and the expected value of the purchase, and then outputs the corresponding predetermined prioritization score. The computed scores are then associated with the particular customer and are placed in prioritization score database 530 . One skilled in the art will appreciate that where predetermined customer prioritization scores are already stored in database 500 (e.g., in the above example) there may not be a need to compute the score again.
[0034] Computing platform 300 then determines whether to prompt the customer to respond to predetermined prioritization queries (S. 70 ). Computing platform 300 may make this determination when there is insufficient information concerning the customer in database 500 . Thus, for example, where database 500 has an insignificant amount of information on the customer, then computing platform 300 may require additional information. This step may be implemented by setting a lower limit on the number of factors corresponding to which database 500 must have information for computing platform 300 to determine a customer's likelihood to purchase. For example, if computing platform 300 determines the need for additional information, then voice response unit 400 prompts the customer to respond to predetermined prioritization queries that are formulated to obtain information concerning the customer's likelihood of purchasing a product or service, or concerning an expected value of a purchase (S. 80 ). For example, the prioritization queries that are formulated to obtain information concerning a customer's financial situation (e.g., whether the customer has a credit card or a checking account) or whether the customer desires to purchase a particular product. Thus, as part of this step, the customer may be prompted for various types of information that may be used in prioritizing the call. While requesting more information from the customer may help to better prioritize the call, seeking more information may delay the call to the extent that the customer abandons it. Thus, the system consistent with the invention prompts the customer for only the optimum amount of information.
[0035] In one implementation consistent with the present invention, a cellular service plan is offered, which can only be purchased by a customer who either has a credit card, or has a checking account and wants to apply for a credit card. As part of this implementation, VRU 400 asks whether the customer owns a credit card. If the customer answers yes, then computing platform 300 assigns the customer a high prioritization score. If, however, the customer answers no, then VRU 400 asks whether the customer has a checking account. If the customer answers yes, then VRU 400 also asks whether the customer would like to apply for a credit card offered by the business. If the customer again answers yes, then platform 300 assigns the customer a middle-level score. The system may predefine a middle-level score for this response because the fact that the customer has a checking account indicates that the customer has at least some means to purchase the offered product. Also, once the customer applies for and is approved for a credit card, the customer may then subscribe to the offered cellular service plan. If, on the other hand, the customer does not apply for a credit card, then the customer is assigned a lower-level score. This is because the customer will not be able to purchase, for example, the cellular service plan. One skilled in the art will appreciate that in one implementation the call may be terminated at this point, for example, where the customer may not purchase the product at issue unless the customer has answered at least one of the questions affirmatively.
[0036] Next, computing platform re-computes the customer prioritization score based on the customer information (S. 90 ). Computing platform 300 may compute the customer prioritization score using several techniques. In one implementation, for example, a table stored in database 500 may include pre-determined scores for each type of response to the prioritization queries. One skilled in the art will recognize, however, that there are numerous other methods for calculating customer prioritization scores.
[0037] If in step S. 40 , the customer does not enter an identification number, then voice response unit 400 prompts the customer to respond to the prioritization queries as described above with regards to steps S. 70 and S. 80 . One skilled in the art will appreciate that the customer inquiries are preferably the same, but they may be different.
[0038] After receiving the customer's responses to the prioritization queries, computing platform 300 computes a customer prioritization score based on the received responses (S. 110 ). Computing platform 300 preferably computes the score in the manner described above with regards to S. 90 . However, one skilled in the art will recognize that there are numerous methods for calculating customer prioritization scores, as discussed earlier.
[0039] Next, based on the computed customer prioritization score stored in database 530 , platform 300 prioritizes the customer inquiry (S. 120 ). As part of this step, the customer inquiry with the highest score may be served first and then the one with the next highest score and so on. Alternatively, the customer inquiry may be assigned to one of a multiple queues based on the computed score, where the queues may have different levels of service. For example, the call may be assigned to a high priority queue, a middle priority queue, or a low priority queue. Higher priority queue preferably has a lower wait time associated with it than the lower priority queue. One skilled in the art will appreciate, however, that more than three queues with different levels of priority may be created to which the customer inquiries could be assigned. In addition, one skilled in the art will recognize the ability to route calls to specific agents or groups of agents with the skill level commensurate with maximizing the value of the customer contact opportunity.
[0040] The timestamp associated with each call may be used to order customer inquiries within each queue. Thus, for example, customer inquiries within a queue are processed in the order they were received according to the time stamp.
[0041] Other modifications and embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. For example, one skilled in the art will appreciate that the systems and methods consistent with the present invention may be used not only to prioritize telephone call, but also may be used to prioritize solicitation received via other means, for example, instant messages over the Internet. Therefore, it is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
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A system and method is provided for prioritizing calls. The disclosed system and method involve receiving an inquiry from a customer. The customer is prompted to input an identification number. If the customer inputs the identification number then customer information associated with that identification number is retrieved, and a customer prioritization score is computed based on the customer information. If the customer fails to input the identification number or no identification number is requested, the customer is prompted to respond to queries and a customer prioritization score is computed based on the customer responses. Based on the computed customer prioritization score, the customer inquiry is prioritized.
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This Application claims the benefit of the priority of Japanese 9-11203, filed Jan. 24, 1997.
The Invention relates to a branching junction box and a method for assembly thereof which is primarily intended for use in automobiles.
BACKGROUND OF THE INVENTION
Branching junction boxes are typically used in the engine compartments of automobiles in order to connect electrical components. Typically, they comprise a busbar substrate which is housed within a casing, the casing consisting of an upper case and a lower case which are joined by a gasket. Conventionally, the casing has two or more male connectors which are used in order to form the electrical connection between two components. The connectors comprise a male cavity having male tab openings therein. Tabs from the busbar substrate extend through the male tab openings and into the male connector cavity in order to provide a point of connection for the electrical components.
In the conventional assembly process of a branching junction box, the lower case is positioned with a positioning tool and a chuck portion of an automated device inserts the busbar substrate therein. Both the first and the last busbar substrates have their male tabs aligned with the male tab openings of the male connector. This can cause a problem in that the tabs do not always align and damage can occur either to the tabs or to the lower or upper case in the area of the male connector.
In order to overcome this misalignment problem, positioning pins have been employed on the positioning tool and corresponding holes have been made in the lower case and the busbar substrate. Such a solution is described in Japanese Utility Model Examined Publication Number 7-33541 (Japanese Utility Model Laid-Open Publication Number 1-146716). In this Publication, it is taught that the two positioning pins and corresponding holes are disposed at diagonal corners. It has been found that, by employing positioning pins along with their respective positioning holes, the misalignment problem and damage to both the tabs and the casing of the junction box can be significantly reduced.
Although the positioning pin and respective positioning holes solve the problem of misalignment, they result in another problem; i.e., the positioning holes allow moisture and dirt to enter the casing. Branching junction boxes are normally mounted in the engine compartment of an automobile. The engine compartment is not a closed area and dirt and water from the front tires and from the road surface often enter the engine compartment and cover the electrical components. Also, moisture from condensation forms on the top of the junction box casing. The pilot holes that are in the casing, both in the upper casing and the lower casing, provide entrances for both dirt and water into the junction box. As can be appreciated, both the dirt and water in the junction box can cause short circuiting and/or damage to the electrical circuitry therein; hence, there is a need to prevent their ingress into the electrical components of the junction box while still employing the positioning pin and positioning holes in its assembly.
SUMMARY OF THE INVENTION
Applicants have solved this problem by employing a positioning cylinder. The positioning cylinder connects the holes in both the upper and lower casing and passes through the positioning holes in the busbar substrate. It closes off the holes in both the upper and lower casings so as to prevent the entry of water and dirt into the junction box. It has also been found that the use of the positioning cylinder makes a more stable junction box in that it maintains the alignment of the busbar substrates and the upper and lower casing after assembly.
Preferably, the positioning cylinders are hollow, thereby acting as conduits for moisture and dirt to pass from the outside top cover of the junction box to the bottom of the junction box without interfering with the electrical circuitry. Additionally, by having the positioning cylinder hollow throughout, it can be mounted on the positioning pin during the assembly of the junction box. Preferably, the positioning cylinder is affixed to the bottom of the upper casing.
Broadly, the junction box and the present Invention comprises:
a lower case and an upper case for holding a busbar substrate;
a first positioning hole disposed in said lower case;
a second positioning hole disposed in said busbar substrate;
a third positioning hole disposed in said upper case; and
a positioning cylinder which closes said first, second, and third positioning holes.
Preferably, the positioning cylinder is hollow to accommodate a positioning pin employed during assembly of the junction box. It is also preferred that the positioning cylinders of the present Invention have a length equal to the distance from the top surface of the upper casing to the bottom surface of the lower casing, when said lower casing and upper casing are joined to form the junction box. It is also preferred that the positioning cylinder is affixed to the upper casing.
The method of the present Invention for assembling the branching junction box comprises:
inserting a positioning pin projecting from a positioning tool through a first positioning hole disposed in the lower casing;
disposing a busbar substrate in said lower casing and inserting the positioning pin through a second positioning hole formed in the busbar substrate;
inserting a hollow positioning cylinder over the positioning pin wherein the cylinder passes through the first positioning hole and second positioning hole; and
placing the upper casing over the lower casing whereby the upper casing has a third positioning hole such that the third positioning hole aligns with the positioning cylinder.
A preferable method of the present Invention for assembly of the junction box comprises:
inserting the positioning pin projecting from the positioning tool through the first positioning hole disposed in the lower casing;
disposing the busbar substrate in the lower case, and inserting the positioning pin through the second positioning hole formed in the busbar substrate;
placing the upper casing over the lower casing, whereby the upper casing has its hollow positioning cylinder projecting therefrom so that the positioning cylinder passes through the first and second positioning holes and over the positioning pin.
The method for assembling a junction box in accordance with the present Invention can also comprise the steps of:
inserting the positioning pin projecting from the positioning tool through the first positioning hole in the lower case;
disposing a busbar substrate in the lower case, and inserting the positioning pin through the second positioning hole formed in the busbar substrate;
placing the upper casing over the lower casing and inserting the positioning pin through the third positioning hole in the upper case;
withdrawing the positioning pin from the first, second, and third positioning holes; and inserting the positioning cylinder through said first, second and third positioning holes so that the positioning cylinder closes the first and third positioning holes.
As can be appreciated, the hollow positioning cylinder can be inserted at any time during the assembly operation. In other words, the hollow positioning cylinder can be mounted on the positioning pin prior to the lower case being positioned on the positioning pin, it can be inserted after the lower case has been inserted over the positioning pin but before the busbar substrate is inserted over the positioning pin; it can be inserted over positioning pin after the busbar substrate has been inserted in the lower casing but before the upper case has been placed over the positioning pin; or it can be inserted after the junction box has been fully completed but it has been removed from the positioning tool. Naturally, where the positioning cylinder is solid, it can only be inserted after the positioning pin has been withdrawn from the positioning holes in the various components of the junction box, unless the positioning pin and the positioning cylinder are one and the same.
Where the positioning cylinder is hollow, it can also be affixed to either the upper casing or the lower casing and, thus, is assembled and inserted over the positioning pin when that component which it is affixed to is first placed over the positioning pin.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, constituting a part hereof, and in which like reference characters indicate like parts,
FIG. 1 illustrates an exploded perspective view of the branching junction box according to the present Invention;
FIG. 2 is a cross section along line A--A of FIG. 1; and
FIG. 3 is a cross section of an assembled junction box according to the present Invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, branching junction box 101 comprises lower case 102, busbar substrate 103, and upper case 104. Lower case 102 and upper case 104 are formed integrally from a synthetic resin. The busbar substrate 103 is held between lower case 102 and upper case 103. A gasket (not shown in the drawing) is employed at the junction of the upper and lower cases in order to prevent water from entering the junction box.
Positioning hole 102a is formed in lower case 102. Lower case 102 is shown having attachment plate 102b for attachment to the engine compartment of a vehicle. Attachment plate 102b has attachment hole 102c formed therein.
Busbar substrate 103 comprises insulating substrate 105 and busbar 106. Positioning hole 105a is formed in insulating substrate 105 at a position corresponding to first positioning hole 102a in lower casing 102. Insulating ribs 105b are formed on insulating substrate 105 at positions corresponding to busbar 106 so as to insulate the busbars and maintain a distance between them. Tabs 106a are formed at prescribed positions one busbar 106 and are is inserted through tab openings 105c of insulating substrate 105.
Positioning cylinder 104a is preferably formed as a projection from upper case 104 to be inserted through positioning holes 102a and 105a. End 104b of positioning cylinder 104a is beveled on its outer perimeter. This beveling forms sloping surface 104c which is sloped toward the outside of positioning cylinder 104a. When upper casing 104 is mounted on lower casing 102, the length of positioning cylinder 104a is set so that it projects past the bottom surface of lower casing 102. Hole 104g is formed in positioning cylinder 104a and is open to the upper surface of upper casing 104.
A male connector cavity 104d is on the upper surface of upper casing 104 and contains male tab opening 104e. Tabs 106a of busbar 106 are inserted through male tab openings 104e from the opposite side of the male connector cavity 104d, and tabs 106a project into male connector cavity 104d, thus forming male connector 104f. Male connector 104f comprises male connector cavity 104d, male tab opening 104e, and tabs 106a.
The preferred assembly operation for making the branch junction box in accordance with the present Invention will now be described with particular reference to FIGS. 2 and 3. Positioning tool 107 is used to assemble branching junction box 101. Positioning pin 108 is projected from positioning tool 107. End 108a of positioning pin 108 is tapered as shown in the Figures.
First, lower case 102 is grasped by a chuck (not shown in the drawing) of an automated device. Positioning hole 102a of lower case 102 is passed over positioning pin 108. Since end 108a of positioning pin 108 is tapered, positioning pin 108 is easily inserted through positioning hole 102a. As a result, lower case 102 is positioned relative to positioning tool 107.
Next, busbar substrate 103 is grasped using the chuck of the automated device, and positioning hole 105a of busbar substrate 103 is aligned with and mounted on positioning pin 108. Here, too, since end 108a is tapered, positioning pin 108 is easily inserted through positioning hole 105a. Since positioning pin 108 is inserted through positioning hole 105a, busbar substrate 103 is reliably assembled and located in lower case 102.
Next, upper case 104 is grasped with the chuck of the automated device. Positioning pin 108 is inserted through hole 104g of positioning cylinder 104a mounted on upper case 104. Positioning cylinder 104a is inserted through positioning hole 102a of lower case 102 and positioning hole 105a of busbar substrate 103. End 104b of positioning cylinder 104a projects past the bottom surface of lower case 102. Sloped surface 104c is formed on end 104b of positioning cylinder 104a so as to allow end 104b to be smoothly guided into and through positioning holes 102a and 105a. Thus, even if there is a slight misalignment of positioning cylinder 104a relative to positioning holes 102a and 105a, it can be reliably fitted into and through the positioning holes. Also, since end 108a of positioning pin 108 is tapered, positioning pin 108 can be easily inserted through hole 104g.
As a result of this assembly, tabs 106a and male tab opening 104e are positioned by positioning pin 108 and positioning cylinder 104a. Thus, tabs 106a can reliably be inserted into male tab openings 104e. Thus, if a force is applied to tab 106a when it is in contact with upper case 104, tab 106a will not be deformed because it is properly aligned with male tab opening 104e.
Referring to FIG. 3, lower case 102, busbar substrate 103, and upper case 104 are reliably and accurately located by positioning pin 108. The length of positioning pin 108 is set so that it projects past the upper surface of upper casing 104 when lower casing 102 and upper casing 104 are assembled.
As can be appreciated from the foregoing description, the positioning of busbar substrate 103 between lower case 102 and upper case 104 is accomplished reliably and damage to tabs 106a and male tab openings 104e is prevented. It will also be appreciated that positioning cylinder 104a closes off the positioning holes in both lower case 102 and upper case 104, thereby preventing dirt and moisture from entering branch junction box 101. In a preferred form of the Invention, reinforcing ribs can be disposed around positioning holes 102a, 105a, and 104g in order to prevent possible damage from either positioning cylinder 104a or from positioning pin 108 during assembly. The present Invention can also be employed without the need for positioning tool 107 and respective positioning pin 108. In other words, employing and positioning cylinder 104a can be done with or without the automated device.
Although the Application has been described only with reference to a busbar substrate, it will be appreciated by those skilled in the art that multiple busbar substrates can be employed in the junction box in accordance with the present Invention. Obviously, where multiple busbar substrates are present each of the busbar substrates has at least one positioning hole which corresponds to positioning pin 108. Although one single set of holes and one positioning cylinder for each busbar substrate have been taught, two or more sets and cylinders may be used for additional positive location as desired.
While only a limited number of specific embodiments of the present Invention have been expressly disclosed, it is, nonetheless, to be broadly construed, and not to be limited except by the character of the clams appended hereto.
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A positioning cylinder to close positioning holes in both the upper and lower casings of a branching junction box so as to prevent dirt and moisture from entering. The positioning cylinder is preferably integral with the upper casing and hollow so as to allow it to fit over a positioning pin employed as a locator during the assembly of the junction box. The positioning cylinder not only closes the holes that are in the upper and lower casing of the junction box, but also stabilizes the busbar substrates that are in the junction box and provides for a more integral and secure junction.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of Invention
[0002] This invention relates to a modified jet engine for use in various land vehicles, sea craft, or flying craft that is housed within a sealed exhaust system and augmented by powerful compressors and air and fuel pumps to deliver oxygen and fuel needs to achieve improved energy efficiency, fuel economy, safety and versatility.
[0003] 2. Description of Related Art
[0004] Numerous land vehicles, flying craft and sea craft utilize solid, gas or liquid fossil fuels in jet or rocket engines to provide thrust for propulsion of the craft/vehicle. While many improvements have been made over the years, the main focus in further efficiency has been in the engine design, with much energy still being wasted or needlessly expelled out of the exhaust of such conventional engine exhaust systems.
[0005] There is a need for an efficient, economical, safe and versatile jet or rocket engine that can minimize wasted fuel.
[0006] Other problems with conventional jet engines are the conventional requirement for an open-mouth intake system in which incoming air enters the jet directly from the atmosphere. Occasionally, objects are sucked into such jet engines where they can damage or completely render inoperable several components of the jet engine. As such, there is a need for an improved jet turbine system that locates an air source remote from the jet turbine itself.
[0007] There also is a need for a jet turbine system that can operate using a multitude of different fuel sources, particularly environmentally friendly sources such as air and water.
SUMMARY OF THE INVENTION
[0008] Applicant has overcome various long felt needs by providing a novel quantum jet turbine system that is housed within an airtight exhaust system. One or more jet turbine engines can share one common exhaust system depending on the size and design of the fuselage and its application. This sealed type quantum jet engine puts to an end the numerous problems associated with conventional jet engine design, since by having the quantum jet engine sealed and housed within one exhaust system, the engine can prevent entry of foreign objects. With this design, independent fuel and compressed air supplies are fed to the sealed jet turbines through sealed feed lines. Moreover, by elimination of an integral open atmosphere intake, the jet is readily adaptable to rocket use for space travel when coupled with a self-contained source of oxygen, such as a liquid or compressed oxygen or air storage tank. Thus, a craft with a quantum jet turbine can fly or land anywhere, including in the presence of flocks of birds, insects, mammals, or dust, while keeping out such foreign objects. Moreover, the system is adaptable to atmospheric, stratospheric or space flight.
[0009] By coupling a turbine of the jet to a generator, thrust generated by the jet can be used to generate electricity to power the electrical needs of the jet engine and the craft.
[0010] By coupling the sealed quantum jet turbine to a compound exhaust system, further efficiencies are achieved by minimizing wasted fuel. That is, conventional jet and rocket engines operate by burning and directly expelling huge amounts of accelerated and expanded gases from their exhaust tubes instantly into the atmosphere, where they can do no further kinetic work. However, when coupled with an efficient exhaust system that harnesses such gases, further efficient use of the kinetic potential of the expelled gases can be realized. This reduces fuel consumption, which in turn reduces payloads by reducing the quantities of fuel needed to be stored, which also itself increases efficiencies since less mass is being propelled. A preferred compound exhaust system can be found in Applicant's U.S. Pat. No. 6,367,739, the subject matter of which is hereby incorporated herein by reference in its entirety.
[0011] Thus, whereas conventional jet and rocket engines expend about 50% or more of the volume of burnt fuels into the atmosphere with no potential to do further kinetic work, the inventive quantum jet engines, when combined with a compound exhaust, are capable of greater potential efficiency by causing the expanding gases to pass through several additional gas expansion chambers, thereby using more of the available kinetic forces from the combusting gases.
[0012] Also, while conventional rockets expel huge amounts of burnt gases at a rather low exit speed, the inventive quantum jet turbine produces kinetic energy for propulsion by expelling the gases at a much lower volume, but at a much higher velocity. Because the kinetic energy in a moving body depends on the square of its speed, it follows that harnessing ultra high speed gas molecules in a small volume and repeating the expansions through several exhaust chambers will result in a highly efficient design capable of reduced fuel consumption and comparable thrust output.
[0013] Moreover, this design incorporates quantum theory by being able to radiate energy discontinuously in quanta.
[0014] This sealed configuration also greatly reduces engine noise. Further noise reduction can be attained by use of a noise canceling device installed in the tip of the thrust vector nozzle of the exhaust.
[0015] The inventive quantum jet turbine should highly revolutionize the air and space transportation system by introducing new fuselage designs, other than conventional tubular craft, that are more adaptable and efficient in using the modified sealed jet engine designs. Such new engines are suitable for land, sea and aircraft needs, as well as spacecraft. For example, the sealed quantum jet engines which can operate without an open-mouth intake design are particularly suitable for saucer-shaped craft, such as disclosed in Applicant's U.S. Pat. No. 6,290,184, the subject matter of which is hereby incorporated herein by reference in its entirety. Such engines may also be used to power land vehicles, such as cars, trucks, vans, commercial trucks, sports cars, race cars, etc. One suitable application of such a land vehicle can be found in Applicant's co-pending U.S. application Ser. No. ______ (Attorney Docket No. 102902), the subject matter of which is hereby incorporated herein by reference in its entirety. One suitable application of such a space craft can be found in Applicant's co-pending U.S. application Ser. No. ______ (Attorney Docket No. 104148), the subject matter of which is hereby incorporated herein by reference in its entirety.
[0016] The inventive quantum jet turbine is also extremely versatile and adaptable to a multitude of possible fuel sources, such as high grade kerosene, high grade diesel fuel, alcohol, liquid hydrogen, liquid oxygen, methane, or other liquid or solid fossil fuels. It can also operate on a mixture, such as a 70/30 mix of high grade (distilled) alcohol (C2H6O), C2H50H, or CH3OH) plus distilled purified water (H 2 O), which results in an efficient, safe and more environmentally friendly fuel that can be smokeless. Other applications may use a 50/50 mixture of alcohol and water, or may use 100% purified water alone (or with superchilled air) as a steam-powered version or a superchilled air version, that are completely environmentally friendly solutions that do not rely on fossil fuels.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The invention will be described with reference to the following drawings wherein:
[0018] FIG. 1 shows a cross-sectional view of an exemplary dual quantum jet turbine engine system housed in a common exhaust system according to the invention with various components only schematically represented;
[0019] FIG. 2 shows a cross-sectional view of a second exemplary embodiment of a dual quantum jet turbine engine system housed in a common exhaust system according to the invention with various components only schematically represented;
[0020] FIG. 3 shows an alternative embodiment of a dual quantum jet turbine engine system having an external turbine generator according to the invention;
[0021] FIG. 4 shows a further alternative embodiment of a dual quantum jet turbine engine system having an external turbine generator according to the invention; and
[0022] FIG. 5 shows an exemplary flying craft within which the inventive quantum jet turbine engine system can be effectively used.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0023] An exemplary embodiment of the invention will be described with reference to FIG. 1 , which shows dual quantum jet turbine engines housed in a common air-tight sealed exhaust system. The jet engines do not take in air directly from the atmosphere as in conventional jet engines. Rather, air or oxygen are received through sealed feed lines from efficient and independent on-board air compressors on the craft or externally provided for the engines. The air compressors may receive and transfer to the quantum jet engines air/oxygen received from either a remote storage tank or a remote air intake separate from the sealed jet turbine engines. The incoming air may be filtered as desired. The incoming air may also be chilled before being pumped into the jet engines. This puts an end to the numerous problems associated with conventional jet engine designs that are prone to sucking large objects into their jet engine intakes.
[0024] Although shown as a dual engine model, the quantum jet turbine system according to exemplary embodiments of the invention can come in mono, dual, tri, quad or more jet engines commonly housed in a single air-tight sealed exhaust system. However, additional advantages are realized when more than one jet engine is provided within each exhaust system. The jet engines are suitably sized and symmetrically arranged within the exhaust system as shown, so as to provide a commonly and centrally oriented gas exhaust flow path.
[0025] In particular, FIG. 1 shows a quantum jet turbine system 100 including multiple separate quantum jet engines 200 housed within a single, common sealed exhaust system, preferably made up of sections A 1 , B 1 , C 1 , D 1 and E 1 . Each quantum jet engine 200 is housed in section A 1 of the exhaust system and includes an outer casing 210 having a sealed, airtight top and converging lower walls 220 defining a combustion chamber 230 therebetween. Each quantum jet engine 200 further includes a combustion exit orifice 240 .
[0026] Within each combustion chamber 230 are located one or more air nozzles 250 . Air nozzles 250 are operably connected to an electric air compressor 1030 through a suitable airtight, sealed feed line (unshown) sized to match the particular jet engine used. Flow from the compressor 1030 to air nozzles 250 may be enhanced by air pump 1020 provided in-line between compressor 1030 and air nozzles 250 . Electric air compressors 1030 may receive air/oxygen from a suitable remote source, such as an on-board storage tank or through shown intake 1060 , which is in communication with the atmosphere, but provided remote from the jet engines 200 . Suitable filtering may be provided at or between the intake 1060 and electric compressors 1030 to prevent large objects from entering the system. For example, in an exemplary embodiment, air valves are located outside the fuselage of the craft on which the jet engines are installed. Air filters may be provided at the tips of the valves. The incoming air is drawn into efficient compressors 1030 , which may house their own filters. Incoming air is then fed through air tubes into a chilling mechanism 1050 , where the chilled air is then pumped into combustion chamber 230 . As shown, the chilling mechanism 1050 , air compressors 1030 , air pumps 1020 , and air intake 1060 are located around the periphery of the jet engine, external of the sealed exhaust system.
[0027] Also within each combustion chamber 230 are located one or more fuel nozzles 260 . Fuel nozzles 260 are operably connected to an on-board fuel storage tank 1070 through a suitable airtight, sealed feedline (unshown). Flow from the tank 1070 may be enhanced by a fuel pump 1010 provided in-line between the tank 1070 and fuel nozzles 260 .
[0028] A spark generator 270 is also provided within the combustion chamber 230 ofeachjet engine 200 . Spark generators 270 may receive electrical power from one or more on-board batteries 1040 , or from generator 400 provided within the common exhaust system. Generator 400 may be operably connected through a shaft or other structure to a turbine 300 having one or more turbine blades placed in the exit path of the combustion exit orifices 240 as shown. Upon generation of combustion gases exiting the various jet engines 200 through orifices 240 , rotation of turbine 300 will occur, which can be used with known and conventional structure to generate electrical energy from generator 400 . Electrical output from generator 400 may be electrically connected to batteries 1040 for recharging purposes and/or may be used to power various auxiliary devices, such as processor 1000 , fuel pump 1010 , air pump 1020 , electric air compressors 1030 , cooling mechanisms 1050 or other devices associated with the engine or craft.
[0029] During operation, quantum jet turbine engines 200 are started by activating battery power to both the air and fuel pumps 1020 , 1010 , respectively. Upon reaching suitable operating pressures, a desired amount of air and fuel will be fed to combustion chambers 230 while spark generators 270 are electrically activated. Upon initial ignition, processor 1000 can cut off battery current and simultaneously activate the main electric air compressors 1030 , while simultaneously activating the fuel and air pumps and other electrical devices by way of current flowing from generator 400 , which is suitably sized to power all required electrical devices.
[0030] The inventive quantum jet turbine system is extremely versatile and adaptable to a multitude of possible fuel sources, such as high grade kerosene, high grade diesel fuel, alcohol, liquid hydrogen, liquid oxygen, methanol, or other solid or liquid fossil fuels. It can also operate on a mixture, such as a 70/30 mix of high grade (distilled) alcohol (C2H6O, C2H50H, or CH3OH) plus distilled purified water (H 2 O), which results in an efficient, safe and more environmentally friendly fuel that can be smokeless. Other applications may use a 50/50 mixture of alcohol and water. However, a most environmentally friendly solution would use 100% purified water alone or with superchilled air as a steam-powered version or a superchilled air version that does not rely on fossil fuels.
[0031] In the exemplary embodiment of FIG. 1 , a possible fuel mix of 70% high grade alcohol (C2H6O) plus 30% distilled water (H 2 O) is used, considering the physical properties of both compounds wherein alcohol has a low boiling point of about 375° F. (197.2° C.) and distilled water has a boiling point of 212° F. (100° C.). Both compounds should be distilled to make them more efficient in achieving faster conversion from liquid to gaseous state, due to the pure substances having no other minerals or deposits that are not combustible and could solidify and produce nozzle clogging or contamination to the combustion chamber walls 210 , which can cause maintenance problems.
[0032] Most alcohols and water mix well. As such, the combination is suitable as a mixture. When this fuel mix is fed to the combustion chambers 230 and ignited by spark generators 270 , the alcohol portion of the mix burns easily, raising the temperature inside the combustion chambers 230 to over 100° C. in a very short time. Thus, expanded gases from the burnt alcohol will start moving at extreme speeds. Likewise, the water portion of the mix (30%) will be rapidly heated and boiled into steam at 100° C., at which time it also expands and moves at great speeds through the combustion chambers 230 towards exit orifices 240 , where the accelerating and expanding gases pass across turbine 300 . This generates electrical power from generator 400 used to continue operation of all electrical accessories.
[0033] The exiting combustion gases enter an upper gas reaction area 510 formed from converging walls 500 of exhaust section B 1 . In this section, the exiting gases further expand and develop high pressure and temperature, ever continuously expanding and rushing toward automatic adjustable gas entry point 520 where the exiting gases then enter a lower gas reaction area 620 formed by diverging walls 600 of exhaust section C 1 . In lower gas reaction area 620 , the exiting gases further increase in pressure and temperature and enter the first stage of a multiple stage compound exhaust system 700 provided at section D 1 of the exhaust system. As shown, there are three stages formed by stage sections 710 , 720 and 730 . Continued flow paths of the exiting gases develop multiple action and reaction forces, acting to further extract kinetic force from the gases and further providing thrust force to propel the jet and associated craft upward. A suitable exemplary multiple stage compound exhaust system is the 3-stage compound exhaust system disclosed in U.S. Pat. No. 6,367,739, the subject matter of which is hereby incorporated herein by reference in its entirety. However, advantages can be achieved by as few as two stages and as many as 10 or more, the higher the number the higher the efficiency.
[0034] The compound exhaust system works by careful control of the kinetic forces acting on the exhaust gases. The gas molecules traveling from the combustion chambers into the first stage of the compound exhaust system at a high speed become abruptly stopped at the top surface of the first stage of the exhaust, where it is known from conservation of energy that the kinetic energy becomes transferred into heat. At this time, the orderly motion of the high speed molecules becomes chaotic, and in an instant the molecules again regroup and move upward, pushing the incoming gases up by reactionary forces. Upon being pushed back by stronger gases coming from the exhaust, the gas molecules further regroup and exit toward the high speed jet nozzles of the exhaust system into the second stage of the exhaust system, where the movement pattern is repeated until the gases reach the third stage where the movement is repeated a third time until the gases finally exit the exhaust chamber.
[0035] Upon exiting from compound exhaust system 700 , exiting combustion gases are received by thrust vector nozzle 800 , which can be suitably controlled to direct the exiting gases in a desired thrust vector that may be other than in axial alignment with the exhaust system. Owing to the sealed intake structure, such a jet engine will operate with reduced sound level than that typically found on conventional jet engines that include a large open-mouth intake system. If additional sound reducing properties are desired, a conventional sound cancellation device 900 can be installed to the end of the exhaust system as known in the art.
[0036] Another exemplary embodiment of a quantum jet turbine system is illustrated in FIG. 2 . This embodiment preferably operates using a mixture of air and water as a power generating propulsion source. This is a much more environmentally friendly solution than that of FIG. 1 . Quantum jet turbine system 1100 includes multiple separate quantum jet engines 1200 housed within a single, common sealed exhaust system, preferably made up of sections A 1 , B 1 , C 1 , D 1 and E 1 . Each quantum jet engine 1200 is housed in section A 1 of the exhaust system, and includes an outer casing 1210 having a sealed, airtight top and converging lower walls 1220 defining upper and lower combustion chambers 1230 A and 1230 B therebetween. Each quantum jet engine 1200 further includes a combustion exit orifice 1240 .
[0037] Within each upper combustion chamber 1230 A are located one or more air nozzles 1250 . Air nozzles 1250 are operably connected to an electric air compressor 2030 through a suitable airtight, sealed feed line (unshown). Flow from the compressor 2030 to air nozzles 1250 may be enhanced by air pump 2020 provided in-line between compressor 2030 and air nozzles 1250 . Also, the air may be fed through chilling mechanisms 2050 prior to reaching air nozzles 250 . Electric air compressors 2030 may receive air/oxygen from a suitable remote source, such as an on-board storage tank or an unshown air intake, which can be in communication with the atmosphere but provided remote from the jet engines 1200 . Suitable filtering may be provided at or between the intake and electric compressors 2030 to prevent large objects from entering the system.
[0038] Also within each combustion chamber 1230 A are located one or more fluid nozzles 1260 for providing water to the combustion chamber. Fluid nozzles 1260 are operably connected to an on-board fluid (water) storage tank 2070 through a suitable airtight, sealed feedline (unshown). Flow from the tank 2070 may be enhanced by a fluid pump 2010 provided in-line between the tank 2070 and fluid nozzles 1260 .
[0039] Because a combustible fuel is not used in this embodiment, there is no spark generator. In its place are provided one or more heating elements 1280 wrapped around inner walls 1210 and 1220 of the combustion chambers and extending downward to preferably cover remaining interior walls of the exhaust system. Insulators may be provided around the exhaust system housing to retain heat inside the exhaust system, keeping the remainder of the craft fuselage unaffected by the heat.
[0040] However, as in the previous embodiment, there is a generator 1400 operably connected through a shaft or other structure to a turbine 1300 having one or more turbine blades placed in the exit path of the combustion exit orifices 1240 as shown. Upon generation of expansion gases exiting the various jet engines 1200 through orifices 1240 , rotation of turbine 1300 will occur, which can be used with known and conventional structure to generate electrical energy from generator 1400 . As in the previous embodiment, electrical output from generator 1400 may be electrically connected to batteries 2040 for recharging purposes and/or may be used to power various auxiliary devices, such as processor 2000 , fluid pump 2010 , air pump 2020 , electric air compressors 2030 , cooling mechanisms 2050 or other devices associated with the engine or craft.
[0041] During operation, quantum jet turbine engines 1200 are started by using either pure distilled water or superchilled air individually or jointly as a propulsion source. Both shown quantum jet engines 1200 will have their upper combustion chambers 1230 A isolated from the lower chambers 1230 B by locking of gas valve locking devices 1290 provided between the upper and lower combustion chambers. At this time, batteries 2040 are activated to raise the temperature of heating elements 1280 to between 200-400° C. or more preferably, in the range of 1000°-3500° C., most preferably between 1000°-2500° C.
[0042] An exemplary heating element 1280 would be an oscillating circuit. This operates by wrapping a coil of wire subjected to a rapidly alternating current around a piece of metal. This induces eddy currents in the metal by induction. The effect is closely related to induced currents discovered by Michael Faraday. The advantage to such a heating element source is that no flame is present and the metal may be treated in a vacuum or in an atmosphere of gas, such as hydrogen. Such heating is not possible with a combustible heat source such as a flame because of either a lack of oxygen or an explosive environment. It would also be possible to provide heating elements 1280 using dielectric heating. With such, when a sheet of non-conducting material is placed between plates of a condenser to which a high frequency oscillator is connected, the rapidly changing electric field in this region causes internal heating of the conductor (such as H 2 O) and the non-conductor (such as chilled air).
[0043] To achieve the higher heat range, preferred heating elements 1280 are of the high heat generator type, which are known and have a capacity to heat a confined vessel from a minimum of 1000° C. up to about 3500° C. The materials of the engines and exhaust are suitably chosen to withstand such heat.
[0044] The compressors and chilling mechanism prepare the air and pressurize the water while the engines are preheated. Once preheated, the high pressure fluid nozzles 1260 will then be opened to spray a fine mist of high pressure water inside both upper combustion chambers 1230 A while the automatic gas locking device 1290 is opened at an appropriate time. At almost the same time, superchilled air is supplied to the combustion chambers. When the system is ready, the initial high pressure steam from within the upper combustion chambers 1230 A will travel at extreme speeds toward the lower combustion chambers 1230 B and further expand and continue its downward path through exit orifices 1240 past turbine 1300 . At this time, processor 2000 can cut off battery current and simultaneously activate the main electric air compressors 2030 , while simultaneously activating the fluid and air pumps and other electrical devices by way of current flowing from generator 1400 , which is suitably sized to power all required electrical devices.
[0045] After passing turbine 1300 , the exhaust gases pass through upper gas expansion area 1510 defined by converging walls 1500 of exhaust section B 1 . In this section, the exiting gases further expand and develop high pressure and temperature ever continuously expanding and rushing toward automatic adjustable gas entry point 1520 where the exiting gases then enter a lower gas reaction area 1620 , formed by diverging walls 1600 of exhaust section C 1 . In lower gas reaction area 1620 , the exiting gases further increase in pressure and temperature and enter the first stage of a multiple stage compound exhaust system 1700 provided at section D 1 of the exhaust system. As shown, there are three stages. Continued flow paths of the exiting gases develop multiple action and reaction forces, acting to further extract kinetic force from the gases and further providing thrust force to propel the jet and associated craft upward. As in the previous example, a suitable exemplary multiple stage compound exhaust system is the 3-stage compound exhaust system disclosed in U.S. Pat. No. 6,367,739, the subject matter of which is hereby incorporated herein by reference in its entirety.
[0046] Upon exiting from compound exhaust system 1700 , exiting combustion gases are received by thrust vector nozzle 1800 , which can be suitably controlled to direct the exiting gases in a desired thrust vector that may be other than in axial alignment with the exhaust system. If additional power generation is needed, additional generators 1900 having turbine blades 1910 may be provided at other positions along the gas flow path, such as after the thrust vector nozzle 1800 as shown in FIG. 2 .
[0047] As an alternative to water as a primary propulsion source, the inventive quantum jet turbine system can use superchilled air as a primary source of power. In such an application, it will be provided with large, efficient chilling or cooling mechanisms 2050 augmented by efficient air compressors 2030 so as to draw in a large volume of air from the atmosphere, such as through a remotely located intake port.
[0048] In operation, this embodiment will be activated by switching on the heating mechanisms 1280 and the secondary chilling/cooling mechanisms 2050 using battery power from batteries 2040 . When a desired temperature of, for example, 200-400° C. or higher is reached, high pressure superchilled air is pumped into both upper combustion chambers 1230 A by air pumps 2020 , and when a suitable pressure builds up, the automatic adjustable locking devices 1290 will automatically open. This allows the much expanded air to enter the lower combustion chambers 1230 B, where the air further expands while passing by turbine 1300 , which activates main generator 1400 . At this time, processor 2000 can shut off battery supply and run accessories from generator power generated by rotation of the turbine 1300 . Heat inside the system can be maintained by use of insulation installed around the exhaust housing.
[0049] When the system is at work and the required heat is maintained, additional high pressure chilled air can be pumped into the lower gas expansion area 1620 by cold air nozzles 1630 to further increase the speed of the highly accelerated gases, which expand since superchilled air expands when heated. As in the previous embodiment, the expanding gases can pass through the compound multiple stage exhaust system to extract additional kinetic energy from the exiting gases before the gases finally leave the exhaust system. Thus, by providing an extended exhaust system and path length, the efficiency of kinetic energy usage can be increased.
[0050] Although internally provided generators are provided in FIGS. 1-2 , externally provided generators can also be provided, as illustrated in the alternative embodiments of FIGS. 3-4 . In particular, FIG. 3 is otherwise the same as that of FIG. 1 , but substitutes external turbines 2300 for the internal turbine 300 of FIG. 1 , and substitutes external generators 2400 for internal generator 400 of FIG. 1 . Turbines 2300 receive a supply of high speed gas from within upper gas expansion area 510 through valves 2310 and incoming flow lines 2320 . The entering gases rotate the blades within the turbine to generate energy from generators 2400 coupled to respective turbines 2300 . The speeding gases may then be pumped by pump 2340 through exit lines 2360 to the lower gas reaction area 620 through valves 2380 . Similarly, FIG. 4 is otherwise the same as that of FIG. 2 , but substitutes external turbines 3300 for the internal turbine 1300 of FIG. 2 , and substitutes external generators 3400 for internal generator 1400 of FIG. 2 . Turbines 3300 receive a supply of high speed gas from within upper gas expansion area 1510 through valves 3310 and incoming flow lines 3320 . The entering gases rotate the blades within the turbine to generate energy from generators 3400 coupled to respective turbines 3300 . The speeding gases may then be pumped by pumps 3340 through exit lines 3360 to the lower gas reaction area 1620 through valves 3380 .
[0051] As mentioned previously, the inventive quantum jet turbine propulsion system is well suited to most any type of vehicle. However, it is particularly suited for application to a spacecraft, such as the craft illustrated in FIG. 5 . This craft 3000 includes various quantum jet turbine propulsion systems 100 spaced around the craft, and may further include other propulsion systems, such as high frequency oscillators 4000 shown below cabin 5000 having windows 5050 . Additional details of such an exemplary craft can be found in Applicant's incorporated co-pending U.S. patent application Ser. No. ______ (Attorney Docket No. 104148).
[0052] As mentioned earlier, the quantum jet turbine engine system preferably has two or more smaller jet engines within a single, common exhaust. This has been found to have improved kinetic energy by using the same amount of fuel, which travels at higher velocities within the smaller jet engines. For example, knowing that kinetic energy KE= 1 / 2 MV 2 , where M is mass and V is velocity, it can be shown how multiple jet engines can achieved increases in both efficiency and output.
[0053] In a mono jet configuration, assuming a 100 lb. mass of high speed gases in the combustion chamber and a gas velocity of 32 feet/second, KE=½MV 2 =100/2×32 2 =51,200 foot pounds of work. In a dual jet configuration, the 100 lb. mass can be equally distributed between the two smaller jets, which operate at a higher gas velocity of 64 feet/second. KE=1/2MV 2 =50/2×64 2 =102,400 foot pounds of work for each engine, for a total of 204,800 foot pounds. Similarly, in a tri engine configuration, which could operate at a higher gas velocity of 128 feet/second, KE=1/2MV 2 =33.3/2×128 2 =272,794 foot pounds of work for each engine, for a total of 818,382 foot pounds. For a quad jet configuration, which would operate at yet a higher velocity because of its smaller jet sizes, KE=½MV 2 =25/2×256 2 =819,200 foot pounds of work for each engine, for a total of 3,276,800 foot pounds.
[0054] When water is used as a propulsion source, steam serves as the exhaust gas. If the exiting and expanding high pressure steam (H 2 O) is cooled in the exhaust chamber while keeping pressure high, the steam can be reverted back to a liquid form, where it can be pumped out and returned to the fuel tank for reuse.
[0055] While specific aspects of the invention have been described with respect to preferred embodiments of the invention, these are not intended to be limiting. Various modifications can be made without departing from the scope of the appended claims.
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A quantum jet turbine propulsion system includes a plurality of jet turbine engines housed within an airtight common exhaust system. The individual jet turbine engines receive propulsion from fuel and air sources remote from the engines, preferably provided by fuel and air pumps and air compressors. The jet turbine propulsion system includes its own turbine driven generator as a self-generating power source, and achieves increased efficiencies through the use of a specially adapted exhaust housing configuration. The jet turbine propulsion system is suitable for use in all forms of land, sea, air and space vehicles. Although many propulsion sources can be used, a preferred propulsion source is a mixture of water and air.
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BACKGROUND
[0001] This invention relates to an insert for an insulated concrete form (ICF) and to an ICF with an insert.
[0002] ICFs are used in the construction of buildings. An ICF typically has a pair of opposed expanded foam panels joined by ties, where each tie terminates at either end in a head embedded in one of the panels. The top and bottom walls of the opposed panels of an ICF may have features that allow the ICF to be interlocked with ICFs above and below it. In use, ICFs are stacked to form walls. Concrete may then be poured into the cavity between the opposed panels of the stacked ICFs. An exterior finish may be applied directly to the outer face of the wall and drywall, or another wall finishing material, may be joined to the inner face of the wall. In this regard, the embedded heads of the ties of the ICFs may be configured so that they give a purchase to fasteners used to join the wall finishing material to the ICFs.
[0003] It may be apparent that ICFs save considerable labour in constructing a building as compared with a more traditional approach of setting up a wall form, pouring concrete into the form, removing the form, constructing a frame for the resulting concrete wall, adding insulation and affixing wall finishings to the frame.
[0004] Despite these advantages, because ICFs are mass produced, they may not be suited to all climates. Further, with ICFs, it may be costly to provide for drainage. In this regard, when applying a stucco finish on a wall formed of ICFs, it is known to first adhere a layer of rectangular foam blocks to the exterior of the ICF wall which blocks have grooves or channels along their back face to provide drainage. The stucco is applied to the front face of these blocks. This approach is time consuming and adds significantly to the cost of the construction project. Therefore, there is a need for improvements.
SUMMARY
[0005] An insert is provided for an ICF which increases the insulation provided by the ICF. This adapts the ICF for use in buildings subject to harsher environments. The insert may have a face with low relief protuberances and this face may abut an inner face of one of the ICF panels. The protuberances may be configured to assist in channeling water penetrating the wall of ICFs down and out of the wall.
[0006] According to an embodiment, there is provided an insert for an insulated concrete form, comprising an expanded foam panel having a plurality of parallel slots extending from a bottom wall of said panel toward a top wall of said panel, each slot extending to a front face of said panel and to a back face of said panel, each slot extending a majority of a distance between said bottom wall and said top wall of said panel, said slots spaced and sized to receive ties between opposed panels of an insulated concrete form such that said panel may be inserted between said opposed panels.
[0007] In another aspect, there is provided an insulated concrete form comprising an expanded foam first panel; an expanded foam second panel opposite said first panel; a plurality of ties extending between said first panel and said second panel, each tie having a first head embedded in said first panel and a second head embedded in said second panel; an expanded foam insert panel having a plurality of parallel slots extending from a bottom wall of said insert panel toward a top wall of said insert panel, each slot extending to a front face of said insert panel and to a back face of said insert panel, each slot extending a majority of a distance between said bottom wall and said top wall of said insert panel, said insert panel inserted between said first panel and said second panel with each slot of said insert panel receiving one of said ties and a front face of said insert panel lying adjacent an inside face of said first panel.
[0008] Other features and advantages will become apparent from the following description in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] In the drawings which illustrate example embodiments,
[0010] FIG. 1 is a partially cut away perspective view of a known ICF,
[0011] FIG. 2 is a front perspective view of an example insert for an ICF, such as the ICF of FIG. 1 ,
[0012] FIG. 3 is a front view of the insert of FIG. 2 ,
[0013] FIG. 4 is a rear perspective view of the insert of FIG. 2 ,
[0014] FIG. 5 is a partially cut away rear perspective view of the insert of FIG. 2 installed in the ICF of FIG. 1 ,
[0015] FIG. 6 is a partially cut away front perspective view of FIG. 5 ,
[0016] FIGS. 7A and 7B are each a schematic view of a portion of a wall of ICFs constructed using the inserts of FIG. 2 ,
[0017] FIG. 8 is a front perspective view of another example insert for an ICF,
[0018] FIG. 9 is a rear perspective view of the insert of FIG. 9 ,
[0019] FIG. 10 is a front view of the insert of FIG. 8 ,
[0020] FIG. 11 is a front perspective view of another example an insert for an ICF,
[0021] FIG. 12 is a rear perspective view of the insert of FIG. 11 , and
[0022] FIG. 13 is a front view of the insert of FIG. 11 .
DESCRIPTION
[0023] Turning to FIG. 1 , an ICF 50 has a first expanded foam panel 52 and a second expanded foam panel 54 joined in spaced relation by ties 56 . Panel 52 has an inside wall 57 . Each tie 56 has a central web portion 58 and terminates at either end in a head 60 . The head 60 at one end of each tie is embedded in the first panel 52 and the head 60 at the opposite end of each tie is embedded in the second panel 54 . A plurality of buttons 62 project above the top wall 61 of the panels 52 , 54 . Buttons 62 can interlock with recesses (not shown) of a like ICF stacked on ICF 50 .
[0024] Turning to FIGS. 2 and 3 , an insert panel 100 that may be used with ICF 50 is fabricated of expanded foam and has a plurality of parallel slots 110 extending from a bottom wall 112 of the panel toward a top wall 114 of the panel. Each slot extends completely through the panel: from the front face 116 of the panel to the back face 118 of the panel. Each slot has a lengthwise extent, L, which extends the majority of the distance, D, between the bottom and top walls of the panel.
[0025] The top wall 114 of the panel has a chamfered edge 115 at the front face 116 of the panel.
[0026] The front face 116 of the panel has a series of low relief protuberances 120 that extend from the bottom wall 112 to the top wall 114 of the insert panel 100 . Each slot 110 extends along one protuberance 120 partially bisecting the protuberance. Each protuberance is shaped as an upper substantially circular portion 122 extending from top wall 114 and a lower substantially circular portion 124 extending from bottom wall 112 , joined by a narrow neck 126 . In view of the shape of the protuberances, it will be apparent that each protuberance, proximate top wall 114 , is radiused.
[0027] The length and width of the insert panel 100 is chosen to match the length and width of the panels of the ICF with which the insert is designed to be used. The width of the slots 110 is chosen so that the slots will fit over the webs of the ties of the ICF with which the insert is designed to be used. The insert panel 100 may have a thickness at the protuberances of about 2″ (about 5 cm), with the protuberances 120 standing proud of the balance of the front face 116 of the insert panel by about 0.4″ (about 1 cm), although other dimensions may be chosen as required.
[0028] With reference to FIG. 4 , the back face 118 of insert 100 is free of protuberances and, indeed, apart from slots 110 , is featureless.
[0029] In use, referencing FIGS. 5 and 6 , insert 100 is inserted between the panels 52 , 54 of the ICF 50 against the inside face 57 ( FIG. 1 ) of panel 52 of the ICF so that the slots 110 of the insert receive the webs 58 of the ties 56 of the ICF. The insert is pushed down until its top wall 112 aligns with the top wall 61 of panel 62 , as shown in FIG. 5 . In this regard, the length of the slots 110 of the insert 100 is chosen so as to allow the insert to be pushed down to this extent.
[0030] Because of the protuberances 120 on the front face 116 of the insert, with the insert against the inside face 57 of panel 52 , the non-protuberanced portions of the front face 116 of the insert stand off from the inside face 57 of the ICF panel 52 .
[0031] ICFs 50 with inserts 100 may be used in constructing a building in substantially the same manner as with known ICFs. However, the ICFs with inserts should be oriented so that panel 52 of each ICF, against which the insert 100 lies, is the outside panel of the ICF. With this orientation, as will be explained, the ICFs with inserts can reduce the prospect of water damage.
[0032] ICFs 50 with insert panels 100 may be stacked to form a wall 130 . FIG. 7A illustrates an example wall 130 with a window frame 132 and insert panels 100 a, 100 b, and 100 c. Even once wall 130 is finished, this frame provides a point of ingress for water from the outside. However, should water penetrate below the window frame 132 past the outer panel of the ICF containing insert 100 a, as illustrated by water path W, this water will be channeled downwardly in the spaces formed between the protuberances 120 of the insert 100 a of the ICF to the insert 100 b of the ICF directly below, and so on, to the bottom of the wall where a gap may be provided to allow the water to leave the wall. In this regard, the chamfered edge 115 of the top wall of each insert panel 100 assists in ensuring water does not become trapped in the joints between panels. To further assist in this regard, optionally, the bottom wall of each insert panel may also have a chamfered edge (not shown).
[0033] There may be situations where the protuberances of one course of the wall are not aligned with the protuberances of the next course of the wall. However, because the protuberances, proximate the top wall of each insert, are radiused, even with mis-aligned protuberances, the inserts will channel water to the bottom of the wall. This is illustrated in FIG. 7B where water from window frame 132 ′ of wall 130 ′ is, channeled along path W′ down insert 100 d and insert 100 e, despite the mis-alignment of the protuberances between these two inserts.
[0034] By channeling water out of the ICF, the inserts reduce the prospect of water being retained within the wall and possibly damaging the wall through repeated freezing and melting cycles.
[0035] FIGS. 8 to 10 illustrate a second embodiment for the inserts. Turning to FIGS. 8 to 10 , like insert 100 of FIGS. 2 to 4 , insert 200 has a plurality of parallel slots 210 extending from a bottom wall 212 of the panel toward a top wall 214 of the panel. However, the protuberances 220 on the front face 216 of insert 200 have a different shape: they are long narrow rectangles extending from the bottom wall 212 to the top wall 214 of the insert panel 200 . As with insert panel 100 , each slot 110 extends along one protuberance 220 partially bisecting the protuberance. The back face 218 of insert 200 is indistinguishable from the back face of insert 100 .
[0036] Insert 200 functions in the same manner as insert 100 . Thus, a wall of ICFs with inserts 200 will channel water that penetrates the ICFs down and out of the wall. Because the protuberances 220 are narrow, if there is misalignment of the protuberances between courses of the wall, it is unlikely the misalignments will result in any water being retained in the wall at the top of the protuberances.
[0037] FIGS. 11 to 13 illustrate a third embodiment for the inserts. Turning to FIGS. 11 to 13 , like insert 200 of FIGS. 8 to 10 , insert 300 has a plurality of parallel slots 310 extending from a bottom wall 312 of the panel toward a top wall 314 of the panel and a plurality of protuberances 320 which are rectangular in shape and extend from the bottom wall 312 to the top wall 314 of the insert panel 300 . Also as with insert panel 200 , with insert panel 300 , each slot 310 extends along one protuberance 320 partially bisecting the protuberance. The back face 318 of insert 300 is indistinguishable from the back face of insert 200 . However, the protuberances 320 of inserts 300 are wider than those of inserts 200 . Nevertheless, insert 300 functions in substantially the same manner as insert 200 .
[0038] Because the back faces of the inserts lack protuberances, concrete poured into a wall formed of the ICFs with inserts will tightly pack against the back faces of the inserts with less risk of lacunae formation.
[0039] In each of the example inserts, the slots are located within the protuberances, where the panel is thickest. This results in a stronger panel than one where the slots are spaced from the protuberances. Further, by locating the slots within the protuberances, water is not channeled into the slots where there may be a risk some water could be trapped by the ties. Nevertheless, inserts where the slots are partially within the protuberances, or spaced from the protuberances, may still assist in reducing the prospect of water damage.
[0040] The inserts, in addition to channeling water out of the wall, increase the insulation provided by the wall (i.e., they increase the R-value of the wall). Notably, even if the front face of the inserts lacked protuberances, the inserts would provide a manner of increasing the insulation provided by the wall. Thus, in some embodiments, inserts could be provided with front faces that lack protuberances and are therefore the same as the back face of inserts 100 , 200 , and 300 .
[0041] The dimensions of the inserts can be adjusted to adapt the inserts for use with different ICFs.
[0042] Although three different shaped protuberances have been described, it will be apparent that insert panels may be provided with other protuberance shapes, sizes, and patterns and still assist in channeling water out from ICFs provided with such insert panels.
[0043] The described insert panels can be formed by blow molding foam beads into an appropriately shaped mold with steam to fuse the beads. Alternatively, the inserts may be formed by wire cutting rectangular foam blocks.
[0044] Other features and advantages will be apparent to those skilled in the art and, therefore, the invention is defined in the claims.
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An insert is provided for an ICF which increases the insulation provided by the ICF. This adapts the ICF for use in buildings subject to harsher environments. The insert may have a protuberanced face which abuts an inner face of one of the ICF panels. The protuberances may be configured so that water penetrating the wall of ICFs is channeled down and out of the wall.
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RELATED APPLICATION
This application is a division of Ser. No. 234,475, filed Aug. 19, 1988, now Pat. No. 4,911,075.
This invention relates to offset lithography. It relates more specifically to improved lithography plates and method and apparatus for imaging these plates.
BACKGROUND OF THE INVENTION
There are a variety of known ways to print hard copy in black and white and in color. The traditional techniques include letterpress printing, rotogravure printing and offset printing. These conventional printing processes produce high quality copies. However, when only a limited number of copies are required, the copies are relatively expensive. In the case of letterpress and gravure printing, the major expense results from the fact that the image has to be cut or etched into the plate using expensive photographic masking and chemical etching techniques. Plates are also required in offset lithography. However, the plates are in the form of mats or films which are relatively inexpensive to make. The image is present on the plate or mate as hydrophilic and hydrophobic (and ink-receptive) surface areas. In wet lithography, water and then ink are applied to the surface of the plate. Water tends to adhere to the hydrophilic or water-receptive areas of the plate creating a thin film of water there which does not accept ink. The ink does adhere to the hydrophobic areas of the plate and those inked areas, usuallY corresponding to the printed areas of the original document, are transferred to a relatively soft blanket cylinder and, from there, to the paper or other recording medium brought into contact with the surface of the blanket cylinder by an impression cylinder.
Most conventional offset plates are also produced photographically. In a typical negative-working, subtractive process, the original document is photographed to produce a photographic negative. The negative is placed on an aluminum plate having a water-receptive oxide surface that is coated with a photopolymer. Upon being exposed to light through the negative, the areas of the coating that received light (corresponding to the dark or printed areas of the original) cure to a durable oleophilics or ink-receptive state. The plate is then subjected to a developing process which removes the noncured areas of the coating that did not receive light (co responding to the light or background areas of the original). The resultant plate now carries positive or direct image of the original document.
If a press is to print in more than one color, a separate printing plate corresponding to each color is required, each of which is usually made photographically as aforesaid. In addition to preparing the appropriate plates for the different colors, the plates must be mounted properly on the print cylinders in the press and the angular positions of the cylinders coordinated so that the color components printed by the different cylinders will be in register on the printed copies.
The development of lasers has simplified the production of lithographic plates to some extent. Instead of applying the original image photographically to the photoresistcoated printing plate as above, an original document or picture is scanned line-by-line by an optical scanner which develops strings of picture signals, one for each color. These signals are then used to control a laser plotter that writes on and thus exposes the photoresist coating on the lithographic plate to cure the coating in those areas which receive light. That plate is then developed in the usual way by removing the unexposed areas of the coating to create a direct image on the plate for that color. Thus, it is still necessary to chemically etch each plate in order to create an image on that plate.
There have been some attempts to use more-powerful lasers to write images on lithographic plates by volatilizing the surface coating so as to avoid the need for subsequent developing. However, the use of such lasers for this purpose has not been entirely satisfactory because the coating on the plate must be compatible with the particular laser which limits the choice of coating materials. Also, the pulsing frequencies of some lasers used for this purpose are so low that the time required to produce a halftone image on the plate is unacceptably long.
There have also been some attempts to use scanning E-beam apparatus to etch away the surface coatings on plates used for printing. However, such machines are very expensive. In addition, they require the workpiece, i.e. the plate, be maintained in a complete vacuum, making such apparatus impractical for day-to-day use in a printing facility.
An image has also been applied to a lithographic plate by electro-erosion. The type of plate suitable for imaging in this fashion and disclosed in U.S. Pat. No. 4,596,733, has an oleophilic plastic substrate, e.g. Mylar brand plastic film, having a thin coating of aluminum metal with an overcoating containing conductive graphite which acts as a lubricant and protects the aluminum coating against scratching. A stylus electrode in contact with the graphite containing surface coating is caused to move across the surface of the plate and is pulsed in accordance with incoming picture signals. The resultant current flow between the electrode and the thin metal coating is by design large enough to erode away the thin metal coating and the overlying conductive graphite containing surface coating thereby exposing the underlying ink receptive plastic substrate on the areas of the plate corresponding to the printed portions of the original document. This method of making lithographic plates is disadvantaged in that the described electro-erosion process only works on plates whose conductive surface coatings are very thin and the stylus electrode which contacts the surface of the plate sometimes scratches the plate. This degrades the image being written onto the plate because the scratches constitute inadvertent or unwanted image areas on the plate which print unwanted marks on the copies.
Finally, we are aware of a press system, only recently developed, which images a lithographic plate while the plate is actually mounted on the print cylinder in the press. The cylindrical surface of the plate, treated to render it either oleophilic or hydrophylici, is written on by an ink jetter arranged to scan over the surface of the plate. The ink jetter is controlled so as to deposit on the plate surface a thermoplastic image-forming resin or material which has a desired affinity for the printing ink being used to print the copies. For example, the image-forming material may be attractive to the printing ink so that the ink adheres to the plate in the areas thereof where the image-forming material is present and phobic to the "wash" used in the press to prevent inking of the background areas of the image on the plate.
While that prior system may be satisfactory for some applications, it is not always possible to provide thermoplastic image-forming material that is suitable for jetting and also has the desired affinity (philic or phobic) for all of the inks commonly used for making lithographic copies. Also, ink jet printers are generally unable to produce small enough ink dots to allow the production of smooth continuous tones on the printed copies, i.e. the resolution is not high enough.
Thus, although there have been all the aforesaid efforts to improve different aspects of lithographic plate production and offset printing, these efforts have not reached full-fruition primarily because of the limited number of different plate constructions available and the limited number of different techniques for practically and economically imaging those known plates. Accordingly, it would be highly desirable if new and different lithographic plates became available which could be imaged by writing apparatus able to respond to incoming digital data so as to apply a positive or negative image directly to the plate in such a way as to avoid the need of subsequent processing of the plate to develop or fix that image.
SUMMARY OF THE INVENTION
Accordingly, the present invention aims to provide various lithographic plate constructions which can be imaged or written on to form a positive or negative image therein.
Another object is to provide such plates which can be used in a wet or dry press with a variety of different printing inks.
Another object is to provide low cost lithographic plates which can be imaged electrically.
A further object is to provide an improved method for imaging lithographic printing plates.
Another object of the invention is to provide a method of imaging lithographic plates which can be practiced while the plate is mounted in a press.
Still another object of the invention is to provide a method for writing both positive and negative or background images on lithographic plates.
Still another object of the invention is to provide such a method which can be used to apply images to a variety of different kinds of lithographic plates.
A further object of the invention is to provide a method of producing on lithographic plates half tone images with variable dot sizes.
A further object of the invention is to provide improved apparatus for imaging lithographic plates.
Another object of the invention is to provide apparatus of this type which applies the images to the plates efficiently and with a minimum consumption of power.
Still another object of the invention is to provide such apparatus which lends itself to control by incoming digital data representing an original document or picture.
Other objects will, in part, be obvious and will, in part, appear hereinafter. The invention accordingly comprises an article of manufacture possessing the features and properties exemplified in the constructions described herein and the several steps and the relation of one or more of such steps with respect to the others and the apparatus embodying the features of construction, combination of elements and the arrangement of parts which are adapted to effect such steps, all as exemplified in the following detailed description, and the scope of the invention will be indicated in the claims.
In accordance with the present invention, images are applied to a lithographic printing plate by altering the plate surface characteristics at selected points or areas of the plate using a non-contacting writing head which scans over the surface of the plate and is controlled by incoming picture signals corresponding to the original document or picture being copied. The writing head utilizes a precisely positioned high voltage spark discharge electrode to create on the surface of the plate an intense-heat spark zone as well as a corona zone in a circular region surrounding the spark zone. In response to the incoming picture signals and ancillary data keyed in by the operator such as dot size, screen angle, screen mesh, etc. and merged with the picture signals, high voltage pulses having precisely controlled voltage and current profiles are applied to the electrode to produce precisely positioned and defined spark/corona discharges to the plate which etch, erode or otherwise transform selected points or areas of the plate surface to render them either receptive or non-receptive to the printing ink that will be applied to the plate to make the printed copies.
Lithographic plates are made ink receptive or oleophilic initially by providing them with surface areas consisting of unoxidized metals or plastic materials to which oil and rubber based inks adhere readily. On the other hand, plates are made water receptive or hydrophilici initially in one of three ways. One plate embodiment is provided with a plated metal surface, e.g. of chrome, whose topography or character is such that it is wetted by surface tension. A second plate has a surface consisting of a metal oxide, e.g. aluminum oxide, which hydrates with water. The third plate construction is provided with a polar plastic surface which is also roughened to render it hydrophilici. As will be seen later, certain ones of these plate embodiments are suitable for wet printing, others are better suited for dry printing. Also, different ones of these plate constructions ar preferred for direct writing; others are preferred for indirect or background writing.
The present apparatus can write images on all of these different lithographic plates having either ink receptive or water receptive surfaces. In other words, if the plate surface is hydrophilic initially, our apparatus will write a positive or direct image on the plate by rendering oleophilici the points or areas of the plate surface corresponding to the printed portion of the original document. On the other hand, if the plate surface is oleophilic initially, the apparatus will apply a background or negative image to the plate surface by rendering hydrophilici or oleophobic the points or areas of that surface corresponding to the background or non-printed portion of the original document. Direct or positive writing is usually preferred since the amount of plate surface area that has to be written on or converted is less because most documents have less printed areas than non-printed areas.
The plate imaging apparatus incorporating our invention is preferably implemented as a scanner or plotter whose writing head consists of one or more spark discharge electrodes. The electrode (or electrodes) is positioned over the working surface of the lithographic plate and moved relative to the plate so as to collectively scan the plate surface. Each electrode is controlled by an incoming stream of picture signals which is an electronic representation of an original document or picture. The signals can originate from any suitable source such as an optical scanner, a disk or tape reader, a computer, etc. These signals are formatted so that the apparatus' spark discharge electrode or electrodes write a positive or negative image onto the surface of the lithographic plate that corresponds to the original document.
If the lithographic plates being imaged by our apparatus are flat, then the spark discharge electrode or electrodes may be incorporated into a flat bed scanner or plotter. Usually, however, such plates are designed to be mounted to a print cylinder. Accordingly, for most applications, the spark discharge writing head is incorporated into a so-called drum scanner or plotter with the lithographic plate being mounted to the cylindrical surface of the drum. Actually, as we shall see, our invention can be practiced on a lithographic plate already mounted in a press to apply an image to that plate in situ. In this application, then, the print cylinder itself constitutes the drum component of the scanner or plotter.
To achieve the requisite relative motion between the spark dIscharge writing head and the cylindrical plate, the plate can be rotated about its axis and the head moved parallel to the rotation axis so that the plate is scanned circumferentially with the image on the plate "growing" in the axial direction. Alternatively, the writing head can move parallel to the drum axis and after each pass of the head, the drum can be incremented angularly so that the image on the plate grows circumferentially. In both cases, after a complete scan by the head, an image corresponding to the original document or picture will have been applied to the surface of the printing plate.
As each electrode traverses the plate, it is supported on a cushion of air so that it is maintained at a very small fixed distance above the plate surface and cannot scratch that surface. In response to the incoming picture signals, which usually represent a half tone or screened image, each electrode is pulsed or not pulsed at selected points in the scan depending upon whether, according to the incoming data, the electrode is to write or not write at these locations. Each time the electrode is pulsed, a high voltage spark discharge occurs between the electrode tip and the particular point on the plate opposite the tip. The heat from that spark discharge and the accompanying corona field surrounding the spark etches or otherwise transforms the surface of the plate in a controllable fashion to produce an image-forming spot or dot on the plate surface which is precisely defined in terms of shape and depth of penetration into the plate.
Preferably the tip of each electrode is pointed to obtain close control over the definition of the spot on the plate that is affected by the spark discharge from that electrode. Indeed, the pulse duration, current or voltage controlling the discharge may be varied to produce a variable sized dot on the plate. Also, the polarity of the voltage applied to the electrode may be made positive or negative depending upon the nature of the plate surface to be affected by the writing, i.e. depending upon whether ions need to be pulled from or repelled to the surface of the plate at each image point in order to transform the surface at that point to distinguish it imagewise from the remainder of the plate surface, e.g. to render it oleophilici in the case of direct writing on a plate whose surface is hydrophilici. In this way, image spots can be written onto the plate surface that have diameters in the order of 0.005 inch all the way down to 0.0001 inch.
After a complete scan of the plate, then, the apparatus will have applied a complete screened image to the plate in the form of a multiplicity of surface spots or dots which are different in their affinity for ink from the portions of the plate surface not exposed to the spark discharges from the scanning electrode.
Thus, using our method and apparatus, high quality images can be applied to our special lithographic plates which have a variety of different plate surfaces suitable for either dry or wet offset printing. In all cases, the image is applied to the plate relatively quickly and efficiently and in a precisely controlled manner so that the image on the plate is an accurate representation of the printing on the original document. Actually using our technique, a lithographic plate can be imaged while it is mounted in its press thereby reducing set up time considerably. An even greater reduction in set up time results if the invention is practiced on plates mounted in a multi-color press because correct color registration between the plates on the various print cylinders can be accomplished electronically rather than manually by controlling the timings of the input data applied to the electrodes that control the writing of the images on the corresponding plates. As a consequence of the forgoing combination of features, our method and apparatus for applying images to lithographic plates and the plates themselves should receive wide acceptance in the printing industry.
BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:
FIG. 1 is a diagrammatic view of an offset press incorporating a lithographic printing plate made in accordance with this invention;
FIG. 2 is an isometric view on a larger scale showing in greater detail the print cylinder portion of the FIG. 1 press;
FIG. 3 is a sectional view taken along line 3--3 of FIG. 2 on a larger scale showing the writing head that applies an image to the surface of the FIG. 2 print cylinder, with the associated electrical components being represented in a block diagram; and
FIGS. 4A to 4F are enlarged sectional views showing imaged lithographic plates incorporating our invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Refer first to FIG. 1 of the drawings which shows a more or less conventional offset press shown generally at 10 which can print copies using lithographic plates made in accordance with this invention.
Press 10 includes a print cylinder or drum 12 around which is wrapped a lithographic plate 13 whose opposite edge margins are secured to the plate by a conventional clamping mechanism 12a incorporated into cylinder 12. Cylinder 12, or more precisely the plate 13 thereon, contacts the surface of a blanket cylinder 14 which, in turn, rotates in contact with a large diameter impression cylinder 16. The paper sheet P to be printed on is mounted to the surface of cylinder 16 so that it passes through the nip between cylinders 14 and 16 before being discharged to the exit end of the press 10. Ink for inking plate 13 is delivered by an ink train 22, the lowermost roll 22a of which is in rolling engagement with plate 13 when press 10 is printing. As is customary in presses of this type, the various cylinders are all geared together so that they are driven in unison by a single drive motor.
The illustrated press 10 is capable of wet as well as dry printing. Accordingly, it includes a conventional dampening or water fountain assembly 24 which is movable toward and away from drum 12 in the directions indicated by arrow A in FIG. 1 between active and inactive positions. Assembly 24 includes a conventional water train shown generally at 26 which conveys water from a tray 26a to a roller 26b which, when the dampening assembly is active, is in rolling engagement with plate 13 and the intermediate roller 22b of ink train 22 as shown in phantom in FIG. 1.
When press 10 is operating in its dry printing mode, the dampening assembly 24 is inactive so that roller 26b is retracted from roller 22b and the plate as shown in solid lines in FIG. 1 and no water is applied to the plate. The lithographic plate on cylinder 12 in this case is designed for such dry printing. See for example plate 138 in FIG. 4D. It has a surface which is oleophobic or non-receptive to ink except in those areas that have been written on or imaged to make them oleophilici or receptive to ink. As the cylinder 12 rotates, the plate is contacted by the ink-coated roller 22a of ink train 22. The areas of the plate surface that have been written on and thus made oleophilici pick up ink from roller 22a. Those areas of the plate surface not written on receive no ink. Thus, after one revolution of cylinder 12, the image written on the plate will have been inked or developed. That image is then transferred to the blanket cylinder 14 and finally, to the paper sheet P which is pressed into contact with the blanket cylinder.
When press 10 is operating in its wet printing mode, the dampening assembly 24 is active so that the water roller 26b contacts ink roller 22b and the surface of the plate 13 as shown in phantom in FIG. 1. Plate 13, which is described in more detail in connection with FIG. 4A, is intended for wet printing. It has a surface which is hydrophilici except in the areas thereof which have been written on to make them oleophyllic. Those areas, which correspond to the printed areas of the original document, shun water. In this mode of operation, as the cylinder 12 rotates (clockwise in FIG. 1), water and ink are presented to the surface of plate 13 by the rolls 26b and 22a, respectively. The water adheres to the hydrophilici areas of that surface corresponding to the background of the original document and those areas, being coated with water, do not pick up ink from roller 22a. On the other hand, the oleophylici areas of the plate surface which have not been wetted by roller 26, pick up ink from roller 22a, again forming an inked image on the surface of the plate. As before, that image is transferred via blanket roller 14 to the paper sheet P on cylinder 16.
While the image to be applied to the lithographic plate 13 can be written onto the plate while the plate is "off press", our invention lends itself to imaging the plate when the plate is mounted on the print cylinder 12 and the apparatus for accomplishing this will now be described with reference to FIG. 2. As shown in FIG. 2, the print cylinder 12 is rotatively supported by the press frame 10a and rotated by a standard electric motor 34 or other conventional means. The angular position of cylinder 12 is monitored by conventional means such as a shaft encoder 36 that rotates with the motor armature and associated detector 36a. If higher resolution is needed, the angular position of the large diameter impression cylinder 16 may be monitored by a suitable magnetic detector that detects the teeth of the circumferential drive gear on that cylinder which gear meshes with a similar gear on the print cylinder to rotate that cylinder.
Also supported on frame 10a adjacent to cylinder 12 is a writing head assembly shown generally at 42. This assembly comprises a lead screw 42a whose opposite ends are rotatively supported in the press frame 10a, which frame also supports the opposite ends of a guide bar 42b spaced parallel to lead screw 42a. Mounted for movement along the lead screw and guide bar is a carriage 44. When the lead screw is rotated by a step motor 46, carriage 44 is moved axially with respect to print cylinder 12.
The cylinder drive motor 34 and step motor 46 are operated in synchronism by a controller 50 (FIG. 3), which also receives signals from detector 36a, so that as the drum rotates, the carriage 44 moves axially along the drum with the controller "knowing" the instantaneous relative position of the carriage and cylinder at any given moment. The control circuitry required to accomplish this is already very well known in the scanner and plotter art.
Refer now to FIG. 3 which depicts an illustrative embodiment of carriage 44. It includes a block 52 having a threaded opening 52a for threadedly receiving the lead screw 42a and a second parallel opening 52b for slidably receiving the guide rod 42b. A bore or recess 54 extends in from the underside of block 52 for slidably receiving a discoid writing head 56 made of a suitable rigid electrical insulating material. An axial passage 57 extends through head 56 for sunugly receiving a wire electrode 58 whose diameter has been exaggerated for clarity. The upper end 58a of the wire electrode is received and anchored in a socket 62 mounted to the to of head 56 and the lower end 58b of the electrode 58 is preferably pointed as shown in FIG. 3. Electrode 58 is made of an electrically conductive metal, such as thoriated tungsten, capable of withstanding very high temperatures. An insulated conductor 64 connects socket 62 to a terminal 64a at the top of block 52. If the carriage 44 has more than one electrode 58, similar connections are made to those electrodes so that a plurality of points on the plate 13 can be imaged simultaneously by assembly 42.
Also formed in head 56 are a plurality of small air passages 66. These passages are distributed around electrode 58 and the upper ends of the passages are connected by way of flexible tubes or hoses 68 to a corresponding plurality of vertical passages 72. These passages extend from the inner wall of block bore 54 to an air manifold 74 inside the block which has an inlet passage 76 extending to the top of the block. Passage 76 is connected by a pipe 78 to a source of pressurized air. In the line from the air source is an adjustable valve 82 and a flow restrictor 84. Also, a branch line 78a leading from pipe 78 downstream from restrictor 84 connects to a pressure sensor 90 which produces an output for controlling the setting of valve 82.
When the carriage 44 is positioned opposite plate 13 as shown in FIG. 3 and air is supplied to its manifold 74, the air issues from the lower ends of passages 66 with sufficient force to support the head above the plate surface. The back pressure in passages 66 and manifold 74 varies directly with the spacing of head 56 from the surface of plate 13 and this back pressure is sensed by pressure sensor 90. The sensor controls valve 82 to adjust the air flow to head 56 so that the tip 58b of the needle electrode 58 is maintained at a precisely controlled very small spacing, e.g. 0.0001 inch, above the surface of plate 13 as the carriage 44 scans along the surface of the plate.
Still referring to FIG. 3, the writing head 56, and particularly the pulsing of its electrode 58, is controlled by a pulse circuit 96. One suitable circuit comprises a transformer 98 whose secondary winding 98a is connected at one end by way of a variable resistor 102 to terminal 64a which, as noted previously, is connected electrically to electrode 58. The opposite end of winding 98a is connected to electrical ground. The transformer primary winding 98b is connected to a DC voltage source 104 that supplies a voltage in the order of 1000 volts. The transformer primary circuit includes a large capacitor 106 and a resistor 107 in series. The capacitor is maintained at full voltage by the resistor 107. An electronic switch 108 is connected in shunt with winding 98b and the capacitor. This switch is controlled by switching signals received from controller 50.
It should be understood that circuit 96 specifically illustrated is only one of many known circuits that can be used to provide variable high voltage pulses of short duration to electrode 58. For example, a high voltage switch and a capacitor-regenerating resistor may be used to avoid the need for transformer 98. Also, a bias voltage may be applied to the electrode 58 to provide higher voltage output pulses to the electrode without requiring a high voltage rating on the switch.
When an image is being written on plate 13, the press 10 is operated in a non-print or imaging mode with both the ink and water rollers 22a and 26b being disengaged from cylinder 12. The imaging of plate 13 in press 10 is controlled by controller 50 which, as noted previously, also controls the rotation of cylinder 12 and the scanning of the plate by carriage assembly 42. The signals for imaging plate 13 are applied to controller 50 by a conventional source of picture signals such as a disk reader 114. The controller 50 synchronizes the image data from disk reader 114 with the control signals that control rotation of cylinder 12 and movement of carriage 44 so that when the electrode 58 is positioned over uniformly spaced image points on the plate 13, switch 108 is either closed or not closed depending upon whether that particular point is to be written on or not written on.
If that point is not to be written on, i.e. it corresponds to a location in the background of the original document, the electrode is not pulsed and proceeds to the next image point. On the other hand, if that point in the plate does correspond to a location in the printed area of the original document, switch 108 is closed. The closing of that switch discharges capacitor 106 so that a precisely shaped, i.e. squarewave, high voltage pulse, i.e. 1000 volts, of only about one microsecond duration is applied to transformer 98. The transformer applies a stepped up pulse of about 3000 volts to electrode 58 causing a spark discharge S between the electrode tip 58b and plate 13. That sparks and the accompanying corona field S' surrounding the spark zone etches or transforms the surface of the plate at the point thereon directly opposite the electrode tip 58b to render that point either receptive or non-receptive to ink, depending upon the type of surface on the plate.
The transformations that do occur with our different lithographic plate constructions will be described in more detail later. Suffice it to say at this point, that resistor 102 is adjusted for the different plate embodiments to produce a spark discharge that writes a clearly defined image spot on the plate surface which is in the order of 0.005 to 0.0001 inch in diameter. That resistor 102 may be varied manually or automatically via controller 50 to produce dots of variable size. Dot size may also be varied by varying the voltage and/or duration of the pulses that produce the spark discharges. Means for doing this are quite well known in the art. Likewise, dot size may be varied by repeated pulsing of the electrode at each image point, the number of pulses determining the dot size (pulse count modulation). If the electrode has a pointed end 58b as shown and the gap between tip 58b and the plate is made very small, i.e. 0.001 inch, the spark discharge is focused so that image spots as small as 0.0001 inch or even less can be formed while keeping voltage requirements to a minimum. The polarity of the voltage applied to the electrode may be positive or negative although preferably, the polarity is selected according to whether ions need to be pulled from or repelled to the plate surface to effect the desired surface transformations on the various plates to be described.
As the electrode 58 is scanned across the plate surface, it can be pulsed at a maximum rate of about 500,000 pulses/sec. However, a more typical rate is 25,000 pulses/sec. Thus, a broad range of dot densities can be achieved, e.g. 2,000 dots/inch to 50 dots/inch. The dots can be printed side-by-side or they may be made to overlap so that substantially 100% of the surface area of the plate can be imaged. Thus, in response to the incoming data, an image corresponding to the original document builds up on the plate surface constituted by the points or spots on the plate surface that have been etched or transformed by the spark discharge S, as compared with the areas of the plate surface that have not been so affected by the spark discharge.
In the case of axial scanning, then, after one revolution of print cylinder 12, a complete image will have been applied to plate 13. The press 10 can then be operated in its printing mode by moving the ink roller 22a to its inking position shown in solid lines in FIG. 1, and, in the case of wet printing, by also shifting the water fountain roller 26b to its dotted line position shown in FIG. 1. As the plate rotates, ink will adhere only to the image points written onto the plate that correspond to the printed portion of the original document. That ink image will then be transferred in the usual way via blanket cylinder 14 to the paper sheet P mounted to cylinder 16.
Forming the image on the plate 13 while the plate is on the cylinder 12 provides a number of advantages, the most important of which is the significant decrease in the preparation and set up time, particularly if the invention is incorporated into a multi-color press. Such a press includes a plurality of sections similar to press 10 described herein, one for each color being printed. Whereas normally the print cylinders in the different press sections after the first are adjusted axially and in phase so that the different color images printed by the lithographic plates in the various press sections will appear in register on the printed copies, it is apparent from the foregoing that, since the images are applied to the plates 13 while they are mounted in the press sections, such print registration can be accomplished electronically in the present case.
More particularly, in a multicolor press, incorporating a plurality of press sections similar to press 10, the controller 50 would adjust the timings of the picture signals controlling the writing of the images at the second and subsequent printing sections to write the image on the lithographic plate 13 in each such station with an axial and/or angular offset that compensates for any misregistration with respect to the image on the first plate 13 in the press. In other words, instead of achieving such registration by repositioning the print cylinders or plates, the registration errors are accounted for when writing the images on the plates. Thus once imaged, the plates will automatically print in perfect register on paper sheet P.
Refer now to FIGS. 4A to 4F which illustrate various lithographic plate embodiments which are capable of being imaged by the apparatus depicted in FIGS. 1 to 3. In FIG. 4A, the plate 13 mounted to the print cylinder 12 comprises a steel base or substrate layer 13a having a flash coating 13b of copper metal which is, in turn, plated over by a thin layer 13c of chrome metal. As described in detail in U.S. Pat. No. 4,596,760, the plating process produces a surface topography or texture which is hydrophylici. Therefore, plate 13 is a preferred one for use in a dampening-type offset press.
During a writing operation on plate 13 as described above, voltage pulses are applied to electrode 58 so that spark discharges S occur between the electrode tip 58b and the surface layer 13c of plate 13. Each spark discharge, coupled with the accompanying corona field S' surrounding the spark zone, melts the surface of layer 13c at the imaging point I on that surface directly opposite tip 58b. Such melting suffices to modify the surface structure or topography at that point on the surface so that water no longer tends to adhere to that surface area. Accordingly, when plate 13 is imaged in this fashion, a multiplicity of non-water-receptive spots or dots I are formed on the otherwise hydrophylici plate surface, which spots or dots represent the printed portion of the original document being copied.
When press 10 is operated in its wet printing mode, i.e. with dampening assembly 24 in its position shown in phantom in FIG. 1, the water from the dampening roll 26b adheres only to the surface areas of plate 13 that were not subjected to the spark discharges from electrode 58 during the imaging operation. On the other hand, the ink from the ink roll 22a does adhere to those plate surface areas written on, but does not adhere to the surface areas of the plate where the water or wash solution is present. When printing, the ink adhering to the plate, which forms a direct image of the original document, is transferred via the blanket cylinder 14 to the paper sheet P on cylinder 16. While the polarity of the voltage applied to electrode 58 during the imaging process described above can be positive or negative, we have found that for imaging a plate with a chrome surface such as the one in FIG. 4A, a positive polarity is preferred because it enables better control over the formation of the spots or dots on the surface of the plate.
FIG. 4B illustrates another plate embodiment which is written on directly and used in a dampening-type press. This plate, shown generally at 122 in FIG. 4B, has a substrate 124 made of a metal such as aluminum which has a structured oxide surface layer 126. This surface layer may be produced by any one of a number of known chemical treatments, in some cases assisted by the use of fine abrasives to roughen the plate surface. The controlled oxidation of the plate surface is commonly called anodizing while the surface structure of the plate is referred to as grain or graining. As part of the chemical treatment modifiers such as silicates, phosphates, etc. are used to stabilize the hydrophilici character of the plate surface and to promote both adhesion and the stability of the photosensitive layer(s) that are coated on the plates.
The aluminum oxide on the surface of the plate is not the crystalline structure associated with corundum or a laser ruby (both are aluminum oxide crystals), and shows considerable interaction with water to form hydrates of the form Al 2 O 3 .H 2 O. This interaction with contributions from silicate, phosphate, etc. modifiers is the source of the hydrophylici nature of the plate surface. Formation of hydrates is also a problem when the process proceeds unchecked. Eventually a solid hydrate mass forms that effectively plugs and eliminates the structure of the plate surface. Ability to effectively hold a thin film of water required to produce nonimage areas is thus lost which renders the plate useless. Most plates are supplied with photosensitive layers in place that protect the plate surfaces until the time the plates are exposed and developed. At this point, the plates are either immediately used or stored for use at a later time. If the plates are stored, they are coated with a water soluble polymer to protect hydrophylici surfaces. This is the process usually referred to as gumming in the trade. Plates that are supplied without photosensitive layers are usually treated in a similar manner.
The of hydrophylici character during storage or extended interruptions while the plate is being used is generally referred to as oxidation in the trade. Depending on the amount of structuring and chemical modifiers used, there is a considerable variation in plate sensitivity to excessive hydration.
When the plate 122 is subjected to the spark discharge from electrode 58, the heat from the spark S and associated corona S' around the spark zone renders oleophylici or ink receptive a precisely defined image point I opposite the electrode tip 58b.
The behavior of the imaged aluminum plate suggests that the image points I are the result of combined partial processes. It is believed that dehydration, some formation of fused aluminum oxide, and the melting and transport to the surface of aluminum metal occur. The combined effects of the three processes, we suppose, reduce the hydrophylici character of the plate surface at the image point. Aluminum is chemically reactive with the result that the metal is always found with a thin oxide coating regardless of how smooth or bright the metal appears. This oxide coating does not exhibit a hydrophylici character, which agrees with our observation that an imaged aluminum-based plate can be stored in air more than 24 hours without the loss of an image. In water, aluminum can react rapidly under both basic and acidic conditions including several electrochemical reactions. The mildly acidic fountain solutions used in presses are believed to have this effect on the thin films of aluminum exposed during imaging resulting in their removal.
Because of the above-mentioned ability of the imaged surface areas of the plate to react with water, protection of the just-imaged plate 122 requires that the plate surface be shielded from contact with water or water-based materials. This may be done by applying ink to the plate without the use of a dampening or fountain solution, i.e. with water roll 26b disengaged in FIG. 1. This results in the entire plate surface being coated with a layer of ink. Dampening water is then applied (i.e. the water roll 26b is engaged) to the plate. Those areas of the plate that were not imaged acquire a thin film of water that dislodges the overlying ink allowing its removal from the plate. The plate areas that were imaged do not acquire a thin film of water with the result that the ink remains in place.
The images generated on a chrome plate show a similar sensitivity to water contact preceding ink contact. However, after the ink application step, the images on a chrome plate are more stable and the plate can be run without additional steps to preserve the image.
The ink remaining on the image points I is quite fragile and must be left to dry or set so that the ink becomes more durable. Alternatively, a standard ink which cures or sets in response to ultraviolet light or heat may be used with plate 122. In this event, a standard ultraviolet lamp 126 may be mounted adjacent to print cylinder 12 as depicted in FIGS. 1 and 2 to cure the particular ink. The lamp 126 should extend the full length of cylinder 12 and be supported by frame members 10a close to the surface of cylinder 12 or, more particularly, the lithographic plate thereon.
We have found that imaging a plate such as plate 122 based on aluminum is optimized if a negative voltage is applied to the imaging electrode 58. This is because positive aluminum ions produced at each image point migrate well in the high intensity current flow of the spark discharge and will move toward the negative electrode.
FIG. 4C shows a plate embodiment 130 suitable for direct imaging in a press without dampening. Plate 130 comprises a substrate 132 made of a conductive metal such as aluminum or steel. The substrate carries a thin coating 134 of a highly oleophobic material such as a fluoropolymer or silicone. One suitable coating material is an addition-cured release coating marketed by Dow Corning under its designation SYL-OFF 7044. Plate 130 is written on or imaged by decomposing the surface of coating 134 using spark discharges from electrode 58. The heat from the spark and associated corona decompose the silicone coating into silicon dioxide, carbon dioxide, and water. Hydrocarbon fragments in trace amounts are also possible depending on the chemistry of the silicone polymers used. Silicone resins do not have carbon in their backbones which means various polar structures such as C--OH are not formed. Silanols, which are Si--OH structures are possible structures, but these are reactive which means they react to form other, stable structures.
Such decomposition coupled with surface roughening of coating 134 due to the spark discharge renders that surface oleophilici at each image point I directly opposite the tip of electrode 58. Preferably that coating is made quite thin, e.g. 0.0003 inch to minimize the voltage required to break down the material to render it ink receptive. Resultantly, when plate 130 is inked by roller 22a in press 10, ink adheres only to those transformed image points I on the plate surface. Areas of the plate not so imaged, corresponding to the background area of the original document to be printed, do not pick up ink from roll 22a. The inked image on the plate is then transferred by blanket cylinder 14 to the paper sheet P as in any conventional offset press.
FIG. 4D illustrates a lithographic plate 152 suitable for indirect imaging and for wet printing. The plate 152 comprises a substrate 154 made of a suitable conductive metal such as aluminum or copper. Applied to the surface of substrate 154 is a layer 156 of phenolic resin, parylene, diazo-resin or other such material to which oil and rubber-based inks adhere readily. Suitable positive working, subtractive plates of this type are available from the Enco Division of American Hoechst Co. under that company's designation P-800.
When the coating 156 is subjected to a spark discharge from electrode 58, the image point I on the surface of layer 156 opposite the electrode tip 58b decomposes under the heat and becomes etched so that it readily accepts water. Actually, if layer 156 is thick enough, substrate 154 may simply be a separate flat electrode member disposed opposite the electrode 58. Accordingly, when the plate 152 is coated with water and ink by the rolls 26b and 22a , respectively, of press 10, water adheres to the image points I on plate 152 formed by the spark discharges from electrode 58. Ink, on the other hand, shuns those water-coated surface points on the plate corresponding to the background or non-printed areas of the original document and adheres only to the non-imaged areas of plate 152.
Another offset plate suitable for indirect writing and for use in a wet press is depicted in FIG. 4E. This plate, indicated at 162 in that figure, consists simply of a metal plate, for example, copper, zinc or stainless steel, having a clean and polished surface 162a. Metal surfaces such as this are normally oleophylici or ink-receptive due to surface tension. When the surface 162a is subjected to a spark discharge from electrode 58, the spark and ancillary corona field etch that surface creating small capillaries or fissures in the surface at the image point I opposite the electrode tip 58b which tend to be receptive to or wick up water. Therefore, during printing the image points I on plate 162, corresponding to the background or non-printed areas of the original document, receive water from roll 26b of press 10 and shun ink from the ink roll 22a. Thus ink adheres only to the areas of plate 162 that were not subjected to spark discharges from electrode 58 as described above and which correspond to the printed portions of the original document.
Refer now to FIG. 4F which illustrates still another plate embodiment 172 suitable for direct imaging and for use in an offset press without dampening. We have found that this novel plate 172 actually produces the best results of all of the plates described herein in terms of the quality and useful life of the image impressed on the plate.
Plate 172 comprises a base or substrate 174, a base coat or layer 176 containing pigment or particles 177, a thin conductive metal layer 178, an ink repellent silicone top or surface layer 184, and, if necessary, a primer layer 186 between layers 178 and 184.
1. Substrate 174
The material of substrate 174 should have mechanical strength, lack of extension (stretch) and heat resistance. Polyester film meets all these requirements well and is readily available. Dupont's Mylar and ICI's Melinex are two commercially available films. Other films that can be used for substrate 174 are those based on polyimides (Dupont's Kapton) and polycarbonates (GE's Lexan). A preferred thickness is 0.005 inch, but thinner and thicker versions can be used effectively.
There is no requirement for an optically clear film o a smooth film surface (within reason). The use of pigmented films including films pigmented to the point of opacity are feasible for the substrate, providing mechanical properties are not lost.
2. Base Coat 176
An important feature of this layer is that it is strongly textured. In this case, "textured" means that the surface topology has numerous peaks and valleys. When this surface is coated with the thin metal layer 178, the projecting peaks create a surface that can be described as containing numerous tiny electrode tips (point source electrodes) to which the spark from the imaging electrode 58 can jump. This texture is conveniently created by the filler particles 177 included in the base coat, as will be described in detail hereinafter under the section entitled Filler Particles 177. Other requirements of base coat 176 include:
(a) adhesion to the substrate 174;
(b) metallizable using typical processes such as vapor deposition or sputtering and providing a surface to which the metal(s) will adhere strongly;
(c) resistance to the components of offset printing inks and to the cleaning materials used with these inks;
(d) heat resistance; and
(e) flexibility equivalent to the substrate.
The chemistry of the base coat that can be used is wide ranging. Application can be from solvents or from water. Alternatively, 100% solids coatings such as characterize conventional UV and EB curable coating can be used. A number of curing methods (chemical reactions that create crosslinking of coating components) can be used to establish the performance properties desired of the coatings. Some of these are:
(a) Thermoset: Typical thermoset reactions are those as an aminoplast resin with hydroxyl sites of the primary coating resin. These reactions are greatly accelerated by creation of an acid environment and the use of heat.
b) Isocyanate-Based: One typical approach are two part urethanes in which an isocynate component reacts with hydroxyl sites on one or more "backbone" resins often referred to as the "polyol" component. Typical polyols include polyethers, polyesters, an acrylics having two or more hydroxyl functional sites. Important modifying resins include hydroxyl functional vinyl resins and cellulose ester resins. The isocyanate component will have two or more isocyanate groups and is either monomeric or oligomeric. The reactions will proceed at ambient temperatures, but can be accelerated using heat and selected catalysts which include tin compounds and tertiary amines. The normal technique is to mix the isocynate functional component(s) with the polyol component(s) just prior to use. The reactions begin, but are slow enough at ambient temperatures to allow a "potlife" during which the coating can be applied.
In another approach, the isocyanate is used in a "blocked" form in which the isocyanate component has been reacted with another component such as a phenol or a ketoxime to produce an inactive, metastable compound This compound is designed for decomposition at elevated temperatures to liberate the active isocyanate component which then reacts to cure the coating, the reaction being accelerated by incorporation of appropriate catalysts in the coating formulation.
(c) Aziridines: The typical use is the crosslinking of waterborne coatings based on carboxyl functional resins. The carboxyl groups are incorporated into the resins to provide sites that form salts with water soluble amines, a reaction integral to the solubilizing or dispersing of the resin in water. The reaction proceeds at ambient temperatures after the water and solubilizing amine(s) have been evaporated upon deposition of the coating. The aziridines are added to the coating at the time of use and have a potlife governed by their rate of hydrolysis in water to produce inert by-products.
(d) Epoxy Reactions: The elevated temperatures cure of boron trifluoride complex catalyzed resins can be used, particularly for resins based on cycloaliphatic epoxy functional groups. Another reaction is based on UV exposure generated cationic catalysts for the reaction. Union Carbide's Cyracure brand system is a commercially available version.
(e) Radiation Cures: These are usually free radical polymerizations of mixtures of monomeric and oligomeric acrylates and methacrylates. Free radicals to initiate the reaction are created by exposure of the coating to an electron beam or by a photoinitiation system incorporated into a coating to be cured by UV exposure. The choice of chemistry to be used will depend on the type of coating equipment to be used and environmental concerns rather than a limitation by required performance properties. A crosslinking reaction is also not an absolute requirement For example, there are resins soluble in a limited range of solvents not including those typical of offset inks and their cleaners that can be used.
3. Filler Particles 177
The filler particles 177 used to create the important surface structure are chosen based on the following considerations:
(a) the ability of a particle 177 of a given size to contribute to the surface structure of the base coat 176. This is dependent on the thickness of the coating to be deposited. This is illustrated for a 5 micron thick (0.0002 inch) coat 176 pigmented with particles 177 of spherical geometry that remain well dispersed throughout deposition and curing of the coat. Particles with diameters of 5 microns and less would not be expected to contribute greatly to the surface structure because they could be contained within the thickness of the coating. Larger particles, e.g. 10 microns in diameter, would make significant contributions because they could project 5 microns above the base coat 176 surface, creating high points that are twice the average thickness of that coat;
(b) the geometry of the particles 177 is important. Equidimensional particles such as the spherical particles described above and depicted in FIG. 4F will contribute the same degree regardless of particle orientation within the base coat and are therefore preferred. Particles with one dimension much greater than the others, acicular types being one example, are not usually desirable. These particles will tend to orient themselves with their long dimensions parallel to the surface of the coating, creating low rounded ridges rather than the desirable distinct peaks. Particles that are platelets are also undesirable. These particles tend to orient themselves with their broad dimensions (faces) parallel to the coating surface, thereby creating low, broad, rounded mounds rather than desirable, distinct peaks;
(c) the total particle content or density within the coating is a function of the image density to be encountered. For example, if the plate is to be imaged at 400 dots per centimeter or 160,000 dots per square centimeter, it would be desirable to have at least that many peaks (particles) present and positioned so that one occurs at each of the possible positions at which a dot may be created. For a coating 5 microns thick, with peaks produced by individual particles 177, this would correspond to a density of 3.2 ×10 8 particles/cubic centimeter (in the dried, cured base coat 176).
Particle sizes, geometries, and densities are readily available data for most filler particle candidates, but there are two important complications. Particle sizes are averages or mean valves that describe the distribution of sizes that are characteristic of a given powder or pigment as supplied. This means that both larger and smaller sizes than the average or mean are present and are significant contributors to particle size considerations. Also, there is always some degree of particle association present when particles are dispersed into a fluid medium, which usually increases during the application and curing of a coating. Resultantly, peaks are produced by groups of particles, as well as by individual particles.
Preferred filler particles 177 include the following:
(a) amorphous silicas (via various commercial processes);
(b) microcrystalline silicas;
(c) synthetic metal oxides (single and in multi-component mixtures);
(d) metal powders (single metals, mixtures and alloys);
(e) graphite (synthetic and natural);
(f) carbon black (via various commercial processes).
Preferred particle sizes for the filler particles to be used is highly dependent on the thickness of the layer 176 to be deposited. For a 5 micron thick layer (preferred application), the preferred sizes fall into one of the following two ranges:
(a) 10+/-5 microns for particles 177 that act predominantly as individuals to create surface structure, and
(b) 4 +/-2 microns for particles that act as groups (agglomerates) to create surface structure.
For both particle ranges, it should be understood that larger and smaller sizes will be present as part of a size distribution range, i.e. the values given are for the average or mean particle size.
The method of coating base layer 176 with the particles 177 dispersed therein onto the substrate 174 may be by any of the currently available commercial coating processes.
A preferred application of the base coat is as a layer 5 +/-2 microns thick. In practice, it is expected that base coats could range from as little as 2 microns to as much as 10 microns in thickness. Layers thicker than 10 microns are possible, and may be required to produce plates of high durability, but there would be considerable difficulty in texturing these thick coatings via the use of filler pigments.
Also, in some cases, the base coat 176 may not be required if the substrate 174 has the proper, and in a sense equivalent, properties. More particularly, the use for substrate 174 of films with surface textures (structures) created by mechanical means such as embossing rolls or by the use of filler pigments may have an important advantage in some applications provided they meet two conditions:
(a) the films are metalizable with the deposited metal forming layer 178 having adequate adhesion, and
(b) their film surface texture produces the important feature of the base coat described in detail above.
4. Thin Metal Layer 178
This layer 178 is important to formation of an image and must be uniformly present if uniform imaging of the plate is to occur. The image carrying (i.e. ink receptive) areas of the plate 172 are created when the spark discharge volatizes a portion of the thin metal layer 178. The size of the feature formed by a spark discharge from electrode tip 58b of a given energy is a function of the amount of metal that is volatized. This is, in turn, a function of the amount of metal present and the energy required to volatize the metal used. An important modifier is the energy available from oxidation of the volatized metal (i.e. that can contribute to the volatizing process), an important partial process present when most metals are vaporized into a routine or ambient atmosphere.
The metal preferred for layer 178 is aluminum, which can be applied by the process of vacuum metallization (most commonly used) or sputtering to create a uniform layer 300 +/-100 Angstroms thick. Other suitable metals include chrome, copper and zinc. In general, any metal or metal mixture, including alloys, that can be deposited on base coat 176 can be made to work, a consideration since the sputtering process can then deposit mixtures, alloys, refractories, etc. Also, the thickness of the deposit is a variable that can be expanded outside the indicated range. That is, it is possible to image a plate through a 1000 Angstrom layer of metal, and to image layers less than 100 Angstroms thick. The use of thicker layers reduces the size of the image formed, which is desirable when resolution is to be improved by using smaller size images, points or dots.
5. Primer 186 (when required)
The primer layer 186 anchors the ink repellent silicone coating 184 to the thin metal layer 178. Effective primers include the following:
(a) silanes (monomers and polymeric forms);
(b) titanates;
(c) polyvinyl alcohols; and
(d) polyimides and polyamide-imides.
Silanes and titanates are deposited from dilute solutions, typically 1-3% solids, while polyvinyl alcohols, polyimides, and polyamides-imides are deposited as thin films, typically 3 +/-1 microns. The techniques for the use of these materials is well known in the art.
6. Ink Repellent Silicone Surface Layer 184
As pointed out in the background section of the application, the use of a coating such as this is not a new concept in offset printing plates. However, many of the variations that have been proposed previously involve a photosensitizing mechanism. The two general approaches have been to incorporate the photoresponse into a silicone coating formulation, or to coat silicone over a photosensitive layer. When the latter is done, photoexposure either results in firm anchorage of the silicone coating to the photosensitive layer so that it will remain after the developing process removes the unexposed silicone coating to create image areas (a positive working, subtractive plate) or the exposure destroys anchorage of the silicone coating to the photosensitive layer so that it is removed by "developing" to create image areas leaving the unexposed silicone coating in place (a negative working, subtractive plate). Other approaches to the use of silicone coatings can be described as modifications of xerographic processes that result in an image-carrying material being implanted on a silicone coating, followed by curing to establish durable adhesion of the particles.
The plates disclosed in the aforementioned U.S. Pat. No. 4,596,733 use a silicone coating as a protective surface layer. This coating is not formulated to release ink, but rather is removable to allow the plates to be used with dampening water applied.
The silicone coating here is preferably a mixture of two or more components, one of which will usually be a linear silicone polymer terminated at both ends with functional (chemically reactive) groups. Alternatively, in place of a linear difunctional silicone, a copolymer incorporating functionality into the polymer chain, or branched structures terminating with functional groups may be used. It is also possible to combine linear difunctional polymers with copolymers and/or branch polymers. The second component will be a multifunctional monomeric or polymeric component reactive with the first component. Additional components and types of functional groups present will be discussed for the coating chemistries that follow.
(a) Condensation Cure Coatings are usually based on silanon (--Si--OH) terminated polydimethylsiloxane polymers (most commonly linear). The silanol group will condense with a number of multifunctional silanes. Some of the reactions are:
__________________________________________________________________________FunctionalGroup Reaction By Product__________________________________________________________________________Acyloxy ##STR1## ##STR2##Acetoxy ##STR3## HOROxime ##STR4## HONCR.sub.1 R.sub.2__________________________________________________________________________
Catalysts such as tin salts or titanates can be used to accelerate the reaction. Use of low molecular weight groups such as CH 3 -- and CH 3 CH 2 -- for R 1 and R 2 also help the reaction rate yielding volatile byproducts easily removed from the coating. The silanes can be difunctional, but trifunctional and tetrafunctional types are preferred.
Condensation cure coatings can also be based on a moisture cure approach. The functional groups of the type indicated above and others are subject to hydrolysis by water to liberate a silanol functional silane which can then condense with the silanol groups of the base polymer. A particularly favored approach is to use acetoxy functional silanes, because the byproduct, acetic acid, contributes to an acidic environment favorable for the condensation reaction. A catalyst can be added to promote the condensation when neutral byproducts are produced by hydrolysis of the silane.
Silanol groups will also react with polymethyl hydrosiloxanes and polymethylhydrosiloxane copolymers when catalyzed with a number of metal salt catalysts such as dibutyltindiacetate. The general reaction is: ##STR5##
This is a preferred reaction because of the requirement for a catalyst. The silanol terminated polydimethylsiloxane polymer is blended with a polydimethylsiloxane second component to produce a coating that can be stored and which is catalyzed just prior to use. Catalyzed, the coating has a potlife of several hours at ambient temperatures, but cures rapidly at elevated temperatures such as 300° F. Silanes, preferably acyloxy functional, with an appropriate second functional group (carboxy phoshonate, and glycidoxy are examples) can be added to increase coating adhesion. A working example follows.
(b) Addition Cure Coatings are based on the hydrosilation reaction; the addition of Si--H to a double bond catalyzed by a platinum group metal complex. The general reaction is: ##STR6##
Coatings are usually formulated as a two part system composed of a vinyl functional base polymer (or polymer blend) to which a catalyst such as a chloroplantinic acid complex has been added along with a reaction modifier(s) when appropriate (cyclic vinyl-methylsiloxanes are typical modifiers), and a second part that is usually a polymethylhydrosiloxane polymer or copolymer. The two parts are combined just prior to use to yield a coating with a potlife of several hours at ambient temperatures that will cure rapidly at elevated temperatures (300° F., for example). Typical base polymers are linear vinyldimethyl terminated polydimethylsiloxanes and dimethysiloxanevinylmethylsiloxane copolymers. A working example follows.
(c) Radiation Cure Coatings can be divided into two approaches. For U.V. curable coatings, a cationic mechanism is preferred because the cure is not inhibited by oxygen and can be accelerated by post U.V. exposure application of heat. Silicone polymers for this approach utilize cycloaliphatic epoxy functional groups. For electron beam curable coatings, a free radical cure mechanism is used, but requires a high level of inerting to achieve an adequate cure. Silicone polymers for this approach utilize acrylate functional groups, and can be crosslinked effectively by multifunctional acrylate monomers.
Preferred base polymers for the surface coatings 184 discussed are based on the coating approach to be used. When a solvent based coating is formulated, preferred polymers are medium molecular weight, difunctional polydimethylsiloxanes, or difunctional polydimethyl-siloxane copolymers with dimethylsiloxane composing 80% or more of the total polymer. Preferred molecular weights range from 70,000 to 150,000. When a 100% solids coating is to be applied, lower molecular weights are desirable, ranging from 10,000 to 30,000. Higher molecular weight polymers can be added to improve coating properties, but will comprise less than 20% of the total coating. When addition cure or condensation cure coatings are to be formulated, preferred second components to react with silanol or vinyl functional groups are polymethylhydrosiloxane or a polymethylhydrosiloxane copolymer with dimethylsiloxane.
Preferably, selected filler pigments 188 are incorporated into the surface layer -84 to support the imaging process as shown in FIG. 4F. The useful pigment materials are diverse, including:
(a) aluminum powders;
(b) molybdenum disulfide powders;
(c) synthetic metal oxides;
(d) silicon carbide powders;
(e) graphite; and
(f) carbon black.
Preferred particle sizes for these materials are small, having average or mean particle sizes considerably less than the thickness of the applied coating (as dried and cured). For example, when an 8 micron thick coating 184 is to be applied, preferred sizes are less than 5 microns and are preferably, 3 microns or less. For thinner coatings, preferred particle sizes are decreased accordingly. Particle 188 geometries are not an important consideration. It is desirable to have all the particles present enclosed by the coating 184 because particle surfaces projecting at the coating surface have the potential to decrease the ink release properties of the coating. Total pigment content should be 20% or less of the dried, cured coating 184 and preferably, less than 10% of the coating. An aluminum powder supplied by Consolidated Astronautics as 3 micron sized particles has been found to be satisfactory. Contributions to the imaging process are believed to be conductive ions that support the spark (arc) from electrode 58 during its brief existence, and considerable energy release from the highly exothermic oxidation that is also believed to occur, the liberated energy contributing to decomposition and volatilization of material in the region of the image formings on the plate.
The ink repellent silicone surface coating 184 may be applied by any of the available coating processes. One consideration not uncommon to coating processes in general, is to produce a highly uniform, smooth, level coating. When this is achieved, the peaks that are part of the structure of the base coat will project well into the silicone layer. The tips of these peaks will be thin points in the silicone layer, which means the insulating effect of the silicone will be lowest at these points contributing to a spark jumping to these points. These projections of the base coat 176 peaks due to particles 177 therein are depicted at P' in FIG. 4F.
______________________________________Working Examples of Ink Repellent Silicone Coatings______________________________________1. Commercial Condensation cure coating supplied by DowCorning:Component Type PartsSyl-Off 294 Base Coating 40VM&P Naptha Solvent 110Methyl Ethyl Ketone Solvent 50Aliminum Powder Filler Pigment 1Blend/Disperse Powder/Then Add:Syl-Off 297 Acetoxy Functional Silane 1.6Blend/Then Add:XY-176 Catalyst Dibutyltindiacetate 1Blend/Then Use:Apply with a #10 Wire Wound RodCure at 300° F. for 1 minute2. Commercial addition cure coating supplied by DowCorning:Component Type PartsSyl-Off 7600 Base Coating 100VM-P Naptha Solvent 80Methyl Ethyl Ketone Solvent 40Aliminum Powder Filler Pigment 7.5Blend/Disperse Powder/Then Add:Syl-Off 7601 Crosslinker 4.8Blend/Then Use:Apply with a #4 Wire Wound RodCure at 300° F. for 1 minuteThis coating can also be applied as a 100% solids coating(same formula without solvents) via offset gravure and curedusing the same conditions.3. Lab coating formulations illustrating condensation cureand addition cure coatings are given in the following Table1. Indentity of indicated components are given in thefollowing Table 2. All can be applied by coating with wirewound rods and cured in a convection oven set at 300° F. usinga 1 minute dwell time. Coating 4 can be applied as a 100%solids coating and cured under the same conditions.______________________________________
TABLE 1______________________________________ CondensationFormulation: Cure Coatings Addition Cure CoatingsParts Basis 1 2 3 4 5 6 7 8______________________________________ComponentsPS - 345.5 20 20 -- -- -- -- -- --PS - 347.5 -- -- 20 -- -- -- -- --PS - 424 -- -- -- -- 50 -- -- --PS - 442 -- -- -- 64 -- -- -- --PS - 445 -- -- -- -- -- 50 -- --PS - 447.6 -- -- -- -- -- -- 50 50PS - 120 2 -- 2 2 4 1 1 --PS - 123 -- 6 -- -- -- -- -- 2T - 2160 -- -- -- 1 1 -- -- --Sly-OFF 297 2 2 2 -- -- -- -- --Dibutyltindi- 1.2 1.2 1.2 -- -- -- -- --acetatePC - 085 -- -- -- 0.05 0.05 0.05 0.1 0.1VM & P 118 114 148 64 55 100 133 133NapthaMethyl Ethyl 60 60 75 -- 55 50 67 67KetoneAluminum 2 2 2 4 3 3 3 3Powder______________________________________
TABLE 2______________________________________ MolecularComponent Type Weight Supplier______________________________________PS - 345.5 Silanol Terminated 77000 Petrarch Polydimethylsiloxane SystemsPS - 347.5 Silanol Terminated 110000 Petrarch Polydimethylsiloxane SystemsPS - 424 Dimethylsiloxane - Petrarch Vinymethylsiloxane Systems Copolymer 7.5% Vinylmethyl ComonomerPS - 442 Vimyldimethyl Terminated 17000 Petrarch Polydimethylsiloxane SystemsPS - 445 Vimyldimethyl Terminated 63000 Petrarch Polydimethylsiloxane SystemsPS - 447.6 Vimyldimethyl Terminated 118000 Petrarch Polydimethylsiloxane SystemsPS - 120 Polymethylhydrosiloxane 2270 Petrarch SystemsPS - 123 (30-35%) Mehylhydro - 2000- Petrarch (65-70%) Dimethylsiloxane 2100 Systems CopolymerT - 2160 1,3,5,7 Tetravinyltetra- Petrarch methylcyclotetrasiloxane SystemsSyl-Off 297 Acetoxy Functional Silane Dow CorningPC - 085 Platinum - Petrarch Cyclvinylmethylsiloxane Systems Complex______________________________________
When plate 172 is subjected to a writing operation as described above, electrode 58 is pulsed, preferably negatively, at each image point I on the surface of the plate. Each such pulse creates a spark discharge between the electrode tip 58b and the plate, and more particularly across the small gap d between tip 58b and the metallic underlayer 178 at the location of a particle 177 in the base coat 176. Where the repellent outer coat 184 is thinnest. This localizing of the discharge allows close control over the shape of each dot and also over dot placement to maximize image accuracy. The spark discharge etches or erodes away the ink repellent outer layer 184 (including its primer layer 186, if present) and the metallic underlayer 178 at the point I directly opposite the electrode tip 58b thereby creating a well I' at that image point which exposes the underlying oleophyllici surface of base coat or layer 176. The pulses to electrode 58 should be very short, e.g. 0.5 microseconds to avoid arc "fingering" along layer 178 and consequent melting of that layer around point I. The total thickness of layers 178, 182 and 184, i.e. the depth of well I', should not be so large relative to the width of the image point I that the well I' will not accept conventional offset inks and allow those inks to offset to the blanket cylinder 14 when printing.
Plate 172 is used in press 10 with the press being operated in its dry printing mode. The ink from ink roller 22a will adhere to the plate only at the image points I thereby creating an inked image on the plate that is transferred via blanket roller 14 to the paper sheet P carried on cylinder 16.
Instead of providing a separate metallic underlayer 178 in the plate as in FIG. 4F, it is also feasible to use a conductive plastic film for the conductive layer A suitable conductive material for layer 184 should have a volume resistivity of 100 ohm centimeters or less, Dupont's 200×C600 Kapton brand film being one example. This is an experimental film in which the normally nonconductive material has been filled with conductive pigment to create a conductive film.
To facilitate spark discharge to the plate, the base coat 176 may also be made conductive by inclusion of a conductive pigment such as one of the preferred base coat pigments identified above.
Also, instead of producing peaks P' by particles 177 in the base coat, the substrate 174 may be a film with a textured surface that forms those peaks. Polycarbonate films with such surfaces are available from General Electric Co. Another possibility is to coat the oleophobic surface layer directly onto a metal or conductive plastic substrate having a textured surface so that the substrate forms the conductive peaks. For example, a silicone-coated textured chrome plate has been successfully imaged in accordance with our process. It is also feasable to provide a textured surface on the surface layer so that the spark discharges are localized at the peaks defined by that texturing.
All of the lithographic plates described above can be imaged on press 10 or imaged off press by means of the spark discharge imaging apparatus described above. The described plate constructions in toto provide both direct and indirect writing capabilities and they should suit the needs of printers who wish to make copies on both wet and dry offset presses with a variety of conventional inks. In all cases, no subsequent chemical processing is required to develop or fix the images on the plates. The coaction and cooperation of the plates and the imaging apparatus described above thus provide, for the first time, the potential for a fully automated printing facility which can print copies in black and white or in color in long or short runs in a minimum amount of time and with a minimum amount of effort.
It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in carrying out the above process, in the described products, and in the constructions set forth without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not a limiting sense.
It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described.
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A printing member for a press with dampening made by forming on a metal body, e.g. of aluminum, an exposed oxidized surface with a grained surface structure which renders that surface hydrophilic and heating the body surface at selected image points thereon without contacting the surface so that there is a transformation of the surface structure which renders it hydrophobic at the image points.
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CROSS-REFERENCE TO RELATED CASES
This application is a continuation of U.S. patent application Ser. No. 10/336,177 filed Jan, 3, 2003, now U.S. Pat. No. 7,194,729, entitled “Dynamic Conversion of Object-Oriented Programs to Tag-Based Procedural Code” which is a divisional of U.S. patent application Ser. No. 09/144,941 filed Sep. 1, 1998, entitled “Dynamic Conversion of Object-Oriented Programs to Tag-Based Procedural Code,” now U.S. Pat. No. 6,504,554 B1, both of which are herein incorporated by reference in their entirety.
FIELD OF THE INVENTION
This invention relates generally to object-oriented application development, and more particularly to dynamically generating tag-based code from object-oriented code.
COPYRIGHT NOTICE/PERMISSION
A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. The following notice applies to the software and data as described below and in the drawings hereto: Copyright© 1997, Microsoft, All Rights Reserved.
BACKGROUND OF THE INVENTION
Internet application development includes techniques and methods that differ from traditional object-oriented application development.
One method of Internet application development utilizes a tag-based display language such as a Hyper Text Markup Language (HTML). However, the static nature of HTML pages makes interactive components for World Wide Web (Web) pages difficult to build and to reuse. Another method of Internet application development utilizes Dynamic HTML (DHTML). DHTML provides for interactive components through a combination of HTML, script code and a document object model. The script code allows web authors to write source code that manipulates items displayed by a web browser.
Object-oriented programming languages, such as the Java programming language, are different from scripting languages. Traditional software developers are frequently more accustomed to using an object-oriented programming model rather than an Internet programming model. In order to develop Internet applications then, traditional software developers must learn a tag-based display language such as DHTML. However, having to learn a new language reduces software development productivity.
Therefore, there is a need for a system that enables object-oriented programmers to generate tag-based procedural code without having to learn a new language. There is also a need for a system that allows software developers to generate Dynamic HTML while writing programs in the Java programming language.
SUMMARY OF THE INVENTION
The above-mentioned shortcomings, disadvantages and problems are addressed by the present invention, which will be understood by reading and studying the following specification. The present invention allows objected oriented programmers, such as those writing in the Java programming language, to write object-oriented code normally as if they were writing to any user interface framework. The present invention converts the code into standard tag-based procedural code, such as HTML or eXtensible Markup Language (XML), for display on a selected Internet web browser or other selected browser and to generate generic HTML if so indicated by the developer.
The programmer creates and manipulates objects that correspond to components of a web page. The objects have an attribute referred as key value pairs. Key value pairs for an object are maintained in arrays and are used to generate styles and attributes, which are further used to generate HTML for desired web browsers. Examples of styles and attributes include color: red, font: bold,. etc. The use of the key value pair data structure facilitates the ease of plugging in different HTML generators or other tag-based language generators to perform the conversion in an objected oriented development environment.
In one embodiment, several states are used when Java code is being written for display of HTML directly on a browser to aid in its generation and modification. An “unbound” state is used until HTML for an element is sent to the browser. When the browser has received the element's corresponding HTML, the element internally moves to a “peer available” state. If the element's “peer” interface is retrieved from the browser, the state becomes “bound”, which indicates the element is associated with a “peer” inside the browser. During the “bound” state the key value pairs are no longer maintained and any changes in properties or attributes are sent directly to the “peer”. In one embodiment, elements are returned from “bound” to “unbound” when elements are removed from the document. The states and movement between them are transparent to the programmer, as they are handled internally by a library or set of development tools.
The present invention describes computers, systems, methods, and computer-readable media of varying scope. In addition to the aspects and advantages of the present invention described in this summary, further aspects and advantages of the invention will become apparent by reference to the drawings and by reading the detailed description that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram of the hardware and operating environment in conjunction with which embodiments of the invention may be practiced.
FIG. 2 is a diagram illustrating a system-level overview of an exemplary embodiment of the invention.
FIG. 3 is a diagram further illustrating the runtime environment and the output of the exemplary embodiment of the invention shown in FIG. 2 .
FIG. 4 is a diagram of the Java object shown in FIG. 3 .
FIG. 5 is a flowchart of a method of generating an HTML element from Java code.
FIG. 6 is a state diagram illustrating three states associated with the Java object of FIG. 4 and actions that cause a transition between the states.
FIGS. 7A , 7 B, 7 C, and 7 D are time lines illustrating example scenarios of the three states shown in FIG. 6 and actions that cause a transition between the states.
FIG. 8 is a chart illustrating a hierarchy for selected HTML class files of the com.ms.wfc.html implementation.
DETAILED DESCRIPTION OF THE INVENTION
In the following detailed description of exemplary embodiments of the invention, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific exemplary embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that logical, mechanical, electrical and other changes may be made without departing from the spirit or scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims.
The detailed description is divided into five sections. In the first section, the hardware and the operating environment in conjunction with which embodiments of the invention may be practiced are described. In the second section, a system level overview of the invention is presented. In the third section, methods for an exemplary embodiment of the invention are provided. In the fourth section, a particular implementation of one embodiment of the invention is described. Finally, in the fifth section, a conclusion of the detailed description is provided.
Hardware and Operating Environment
FIG. 1 is a diagram of the hardware and operating environment in conjunction with which embodiments of the invention may be practiced. The description of FIG. 1 is intended to provide a brief, general description of suitable computer hardware and a suitable computing environment in conjunction with which the invention may be implemented. Although not required, the invention is described in the general context of computer-executable instructions, such as program modules, being executed by a computer, such as a personal computer. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types.
Moreover, those skilled in the art will appreciate that the invention may be practiced with other computer system configurations, including hand-held devices, multiprocessor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, and the like. The invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.
The exemplary hardware and operating environment of FIG. 1 for implementing the invention includes a general purpose computing device in the form of a computer 20 , including a processing unit 21 , a system memory 22 , and a system bus 23 that operatively couples various system components include the system memory to the processing unit 21 . There may be only one or there may be more than one processing unit 21 , such that the processor of computer 20 comprises a single central-processing unit (CPU), or a plurality of processing units, commonly referred to as a parallel processing environment. The computer 20 may be a conventional computer, a distributed computer, or any other type of computer; the invention is not so limited.
The system bus 23 may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. The system memory may also be referred to as simply the memory, and includes read only memory (ROM) 24 and random access memory (RAM) 25 . a basic input/output system (BIOS) 26 , containing the basic routines that help to transfer information between elements within the computer 20 , such as during start-up, is stored in ROM 24 . The computer 20 further includes a hard disk drive 27 for reading from and writing to a hard disk, not shown, a magnetic disk drive 28 for reading from or writing to a removable magnetic disk 29 , and an optical disk drive 30 for reading from or writing to a removable optical disk 31 such as a CD ROM or other optical media.
The hard disk drive 27 , magnetic disk drive 28 , and optical disk drive 30 are connected to the system bus 23 by a hard disk drive interface 32 , a magnetic disk drive interface 33 , and an optical disk drive interface 34 , respectively. The drives and their associated computer-readable media provide nonvolatile storage of computer-readable instructions, data structures, program modules and other data for the computer 20 . It should be appreciated by those skilled in the art that any type of computer-readable media which can store data that is accessible by a computer, such as magnetic cassettes, flash memory cards, digital video disks, Bernoulli cartridges, random access memories (RAMs), read only memories (ROMs), and the like, may be used in the exemplary operating environment.
A number of program modules may be stored on the hard disk, magnetic disk 29 , optical disk 31 , ROM 24 , or RAM 25 , including an operating system 35 , one or more application programs 36 , other program modules 37 , and program data 38 . A user may enter commands and information into the personal computer 20 through input devices such as a keyboard 40 and pointing device 42 . Other input devices (not shown) may include a microphone, joystick, game pad, satellite dish, scanner, or the like. These and other input devices are often connected to the processing unit 21 through a serial port interface 46 that is coupled to the system bus, but may be connected by other interfaces, such as a parallel port, game port, or a universal serial bus (USB). A monitor 47 or other type of display device is also connected to the system bus 23 via an interface, such as a video adapter 48 . In addition to the monitor, computers typically include other peripheral output devices (not shown), such as speakers and printers.
The computer 20 may operate in a networked environment using logical connections to one or more remote computers, such as remote computer 49 . These logical connections are achieved by a communication device coupled to or a part of the computer 20 ; the invention is not limited to a particular type of communications device. The remote computer 49 may be another computer, a server, a router, a network PC, a client, a peer device or other common network node, and typically includes many or all of the elements described above relative to the computer 20 , although only a memory storage device 50 has been illustrated in FIG. 1 . The logical connections depicted in FIG. 1 include a local-area network (LAN) 51 and a wide-area network (WAN) 52 . Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets and the Internet.
When used in a LAN-networking environment, the computer 20 is connected to the local network 51 through a network interface or adapter 53 , which is one type of communications device. When used in a WAN-networking environment, the computer 20 typically includes a modem 54 , a type of communications device, or any other type of communications device for establishing communications over the wide area network 52 , such as the Internet. The modem 54 , which may be internal or external, is connected to the system bus 23 via the serial port interface 46 . In a networked environment, program modules depicted relative to the personal computer 20 , or portions thereof, may be stored in the remote memory storage device. It is appreciated that the network connections shown are exemplary and other means of and communications devices for establishing a communications link between the computers may be used.
The hardware and operating environment in conjunction with which embodiments of the invention may be practiced has been described. The computer in conjunction with which embodiments of the invention may be practiced may be a conventional computer, a distributed computer, or any other type of computer; the invention is not so limited. Such a computer typically includes one or more processing units as its processor, and a computer-readable medium such as a memory. The computer may also include a communications device such as a network adapter or a modem, so that it is able to communicatively couple other computers.
System Level Overview
A system level overview of the operation of an exemplary embodiment of the invention is described by reference to FIGS. 2 , 3 and 4 .
A high-level view of a system for generating HTML from Java code 200 is shown in FIG. 2 . The system shown in FIG. 2 comprises an input 202 , a runtime environment 204 and an output 212 . In one embodiment, the input 202 is source code written in the Java programming language. The Java source code is compiled into byte code to be read by the runtime environment 204 .
The runtime environment 204 of the present invention provides software developers the ability to translate object-oriented programs into a tag-based display language. The tag-based display language generated from a single program can be tailored to one of many different web browsers. In one embodiment, the runtime environment 204 comprises byte code 206 , a plurality of HTML class files 208 and one or more generators 210 . The byte code 206 represents the compiled Java source code. The plurality of class files 208 provide functionality enabling software developers to author HTML pages using only the Java language. An example implementation of the class files 208 is described later in the section entitled “Microsoft com.ms.wfc.html Implementation.” The generator 210 generates HTML from the Java code. The output 212 is a string of formatted text, such as HTML, that is tailored to one of several different browsers.
FIG. 3 is a diagram further illustrating the runtime environment 204 and the output 212 of the example embodiment of the invention shown in FIG. 2 . In the example embodiment shown in FIG. 3 , a Java object 302 exists in memory of a computer during the execution of the byte code 206 at run time. The Java object 302 corresponds to an HTML element. The HTML element is any item or component that appears on a web page. Example HTML elements include buttons, list boxes, check boxes and tables. When the Java object is added to a web document, a generator 210 is called. At that point, an HTML string 306 is generated comprising the tags and text that represent the HTML element.
Generator 210 generates the HTML string 306 for the Java object 302 . In one embodiment HTML string 306 comprises tags and text for any common document-layout and hyperlink-specification language. In an example embodiment, the generator 210 generates the HTML string in a form for display by an Internet Explorer version 4.0 web browser. In alternate embodiments, the generator 210 generates the HTML string in a form for display by other commonly available browsers such as Netscape Navigator version 3.0. In a further embodiment, the generator 210 generates formatted text other than HTML tags and text.
Generator 210 allows developers to write a single program that dynamically generates a formatted text string for a selected one of a variety of sources. For example, a single program generates a formatted text string to display the text “Hello World” in red bold characters by an Internet Explorer brand web browser and by a Netscape Navigator brand web browser even though the browsers require a different syntax. One version of the Internet Explorer brand web browser requires the following syntax for tags and text:
<span id=myspan style=“font-weight:bold;color:red”>Hello World</span>.
In contrast, one version of the Netscape Navigator brand web browser requires the following syntax for tags and text:
<B><Font color=red>Hello World</font></b>.
From the same program, generator 210 generates the string of the tags and text with the syntax required by the Internet Explorer brand web browser if that web browser is specified or the Netscape Navigator brand web browser is that web browser is specified. The HTML string 306 is available to any one of a number of mediums such as a screen 308 , a clipboard 310 , a web/mail client 312 or a disk 314 for example. Screen 308 represents any program for retrieving and displaying files and following links to other files, including any commonly available web browsers such as Internet Explorer and Netscape Navigator. Screen 308 receives and displays an HTML document containing the HTML string 306 . Clipboard 310 represents any file or memory area where data is stored temporarily before being copied to another location. Clipboard 310 receives HTML string 306 and makes HTML string 306 available to any applications that recognize text generally or HTML text specifically. For example, HTML string 306 received by clipboard 310 is available to word processors such as Microsoft Word. Web client 312 represents a web client capable of receiving the HTML string 306 from a web server through an HTTP connection. Web mail 312 represents a means of transporting the HTML string 306 as a mail component. Disk 314 is any commonly available storage medium. In an off-line mode of the invention, such as the command shell environment further described below, the HTML string 306 is written to a file on the disk 314 .
FIG. 4 is a more detailed diagram of the Java object 302 shown in FIG. 3 . Java object 302 comprises an attribute referred to herein as key value pairs 402 . The key value pairs 402 are parallel arrays of keys and values. Key value pairs 402 are used to generate styles and attributes for an HTML element. A first array 404 of the key value pair stores data representing attributes for the HTML element. Attributes are qualities that pertain to an HTML element. Attributes have the syntax “name=value” and are space delimited. A second array 406 of the key value pair stores data representing styles for the HTML element. Styles are formatting characteristics that pertain to the HTML element. Styles have the syntax “name:value” and are semicolon delimited. Thus, the key value pairs 402 store information about how the Java developer manipulated a Java object which represents an HTML element. The generator of FIG. 3 uses the data in the key value pairs 402 to generated HTML tailored to a selected one of a variety of different browsers.
The system level overview of the operation of an example embodiment of the invention has been described in this section of the detailed description. The present invention provides software developers who program in object-oriented languages, such as the Java programming language, the ability to translate object-oriented programs into a tag-based display language such as HTML. The tag-based display language generated from a single program can be tailored to a variety of different browsers. In one embodiment, the tag-based display language is tailored for Internet Explorer Version 4.0.
Methods of an Exemplary Embodiment of the Invention
In the previous section, a system level overview of the operation of an example embodiment of the invention was described. In this section, the particular methods of such an example embodiment are described by reference to a series of flowcharts, state diagrams and time lines. The methods to be performed constitute computer programs made up of computer-executable instructions. Describing the methods by reference to flowcharts, state diagrams and time lines enables one skilled in the art to develop such programs including such instructions to carry out the methods on suitable computerized systems.
One embodiment of a method of generating an HTML element from Java code is shown in FIG. 5 . The method begins when a Java object (block 502 ) is created by a programmer. Data representing style and attribute information about the Java object is stored in key value pair arrays until the Java object is added to the web browser as an HTML element (block 504 ). After the object is added to the browser, the HTML element can be directly accessed for modifications or to attach an event (block 506 ) for example. At any point during the method shown in FIG. 5 , the Java object corresponding to a particular HTML element will be in one of three states. The states comprise an “unbound” state, a “peer available” state and a “bound” state. The states and movement between the states is transparent to the programmer.
FIG. 6 is a state diagram illustrating the three states and actions that cause a transition between states. The states are represented by circles or nodes in the state diagram. The states are unbound 602 , peer available 604 and bound 606 .
When a Java object is created, it is in an unbound state 602 and remains unbound until a corresponding HTML element is sent to a browser. While in the unbound state 602 , information about the Java object is stored as key value pairs. Modifications to the Java object such as setting or removing attribute information and style information are made without changing the state of the Java object (line 608 ).
However, when the Java object is added to a browser (line 610 ), the state of the object is changed to peer available 604 . A peer available state indicates that an appropriate HTML scripting object, or “peer”, is available inside the browser. In order to add the Java object to the browser, a generator generates an HTML string representing the HTML element. The generator uses the data stored in the key value pairs to generate the applicable HTML string. The Java object will remain in the peer available 604 state until the HTML element is needed such as for binding events, setting properties, or calling methods on the peer (line 612 ). Leaving the Java object in the peer available state 604 until the peer is needed prevents resource intensive searching that is required to identify or find the browser instance “peer” of the element. Since the Java object may not need to be identified again, leaving it in the peer available state enhances resource utilization and overall performance.
The HTML peer is only retrieved if it is needed. In which case, the peer is retrieved and the state of the Java object is changed to bound 606 . The bound state 606 indicates the element is associated with a “peer” inside the browser. During the bound state 606 the KeyValuePairs are no longer maintained for the Java object and any changes in styles or attributes are sent directly to the “peer” on the browser.
Elements are changed from the bound state 606 or from the peer available state 604 to the unbound state 602 when the elements are removed from the document (line 614 ). If an element is removed from a document, the HTML of the peer element is translated and the data is used to re-build the corresponding KeyValuePair arrays. In an alternate embodiment, elements move from the unbound state 602 directly to the bound state 606 . In an additional embodiment, elements are returned from the bound state 606 to the peer available state 604 . It is contemplated and within the scope of the invention that elements are capable of moving from any one state to any other state shown in the state diagram of FIG. 6 . The states and movement between them are transparent to the programmer.
FIGS. 7A , 7 B, 7 C and 7 D are time lines illustrating example scenarios of the three states and actions that cause a transition between the states. In FIG. 7A a new Java object is created at point A. The Java object is in the unbound state 702 . At point B the Java object is modified. Because the Java object is not available to the browser yet, any modifications to the Java object do not change the state. Thus, after modification of the Java object, the object remains in the unbound state 704 . In a web server environment, as further described below, the Java object remains in the unbound state as shown in FIG. 7A .
In FIG. 7B a new Java object is created at point A. The Java object is in the unbound state 706 . At point B the Java object is added to a browser. Adding the object to the browser changes the state of the object from unbound 706 to peer available 708 . If no further manipulations of the Java object occur, the object will remain in the peer available state 708 .
In FIG. 7C a new Java object is created at point A. The Java object is in the unbound state 710 . At point B the Java object is added to a browser. Adding the object to the browser changes the state of the object from unbound 710 to peer available 712 . At point C the Java object is modified. Because the object is in peer available state 712 and thus available to the browser, the further manipulation of the object changes the state from peer available 712 to bound 714 . In the bound state 714 the key value pairs are no longer maintained for the object and any modifications to styles or attributes are sent directly to the peer element on the browser rather than performed on the object. The object will remain in the bound state 714 unless is it removed from the browser.
In FIG. 7D a new Java object is created at point A. The Java object is in the unbound state 716 . At point B the Java object is added to a browser. Adding the object to the browser changes the state of the object from unbound 716 to peer available 718 . At point C an event is attached to the object. Because the Java object is in peer available state 718 and thus available to the browser, the attaching of an event to the object changes the state from peer available 718 to bound 720 . The object remains in the bound state 720 until is it removed from the browser at point D. When the object is removed from the browser, the object returns to the unbound state 722 . When returning an object to the unbound state 722 , the HTML of the peer element is translated and the data is used to re-build the corresponding key value pair arrays.
The programming model presented to the developer masks the location in the network topology that the Java code is executing. As detailed above the Java code works closely with the browser in the client environment to create an interaction with the user. The Java code will also run in a Web server environment. In this environment the Java code is executed in response to an HTTP URL request from a remote client. The request triggers the Java objects, which start in the “unbound” state, to generate the tag formatted string used as the reply to the client's request. The Java objects then moves into a special-case state called “server-sent” which prevents (through the use of Java runtime exceptions) the developer from changing attributes or styles on the object.
The Java code will also execute in a command shell environment. In the command shell environment the code runs in response to the computer user entering commands into a command window. The Java objects never move past the “unbound” state. The generated tag-formatted text is written to permanent storage in this case (e.g. a hard disk) for another software process to retrieve the text at a later time.
The particular methods performed by an exemplary embodiment of the invention have been described.
Microsoft's com.ms.wfc.html Implementation
In this section of the detailed description, a particular implementation of the invention is described.
Windows Foundation Classes (WFC) are a set of Java class libraries that enable software developers to build Microsoft Windows-based applications with the Java programming language. The com.ms.wfc.html package of the Windows Foundation Classes for Java framework lets a developer access Dynamic HTML (DHTML) on a Web page directly from a Java class.
The HTML package of WFC contains a set of classes that enable developers to. generate Dynamic HTML code without having to learn a new language. The HTML class library gives developer's control over the Web page hosting the application. Developers can also change the Web container at run time. Using the HTML Class Library, developers can author Dynamic HTML pages using only the Java Language. The resulting Java application can directly render Dynamic HTML during runtime.
FIG. 8 is a chart illustrating a hierarchy for selected HTML class files of the com.ms.wfc.html package. In one embodiment, the HTML classes comprise style base 802 , style 804 , element 806 , base container 808 and document 810 . Style base 804 is the base class for style 804 and element 806 . Element 806 is the base class for base container 808 .
At the base of the hierarchy is the style base 802 . The style base is an encapsulation of styles. Styles comprise border (including color, style, width), color (including back, fore), cursor, font, margin/padding, text alignment, visible and z-index and the like. Style base 802 has the following attributes: defaultUnit, sized, moved (booleans), styles (Key ValuePairs) and stylePeer.
Key value pairs are parallel arrays of keys and values. Key value pairs are used to generate styles and attributes for an HTML element. A first array of the key value pair stores data representing attributes for the HTML element. Attributes have the syntax “name=value” and are space delimited. A second array of the key value pair stores data representing styles for the HTML element. Styles have the syntax “name:value” and are semicolon delimited.
Style object 804 is derived from style base 802 . Style object 804 is a collection of properties. Each time a change is made to the Style object 804 during run time, all elements 806 to which the style object 804 is applied are updated.
Element 806 is derived from style base 802 . Button 812 and list box 814 are examples of elements. Element 806 has the following attributes: parent, document, events, closetag (boolean), html_generator, attributes (KeyValuePairs), style, id (string), peer and found (boolean). Each element has a unique id attribute that identifies the element in the document. The html_generator attribute indicates a generator to use when creating the HTML string for the element. In an example embodiment, the html_generator is a generator for HTML recognized by an Internet Explorer web browser version 4.0. An element does not become visible to an end user until the element is added to a browser. Elements 806 can trigger events.
Base container 808 is derived from element 806 . Containers are elements that can hold other elements. Base container 808 allows parent-child relationships. A container has an array of elements that are the children of the container. Each one of the elements (which can be other containers) added to the container become children of the container. The elements do not become part of a document (and thus available to the browser) until the topmost container which is not part of any other container is added to the document.
In one embodiment, when children are added to a container, the state of the container is checked. If the state of the container is “unbound”, then the children are placed in the array for that container and the operation is complete. However, if the state of the container is “bound” or “peer available”, in addition to placing the children in the array for the container, the children must be made available to the browser. The children become either “bound” or “Peer Available”. HTML is generated for the children and the HTML is inserted into the browser at that point.
The following example illustrates using the com.ms.wfc.html package to implement Java and DHTML. The following example illustrates building a simple DHTML page using the Java programming language. The Java programming language is known in the art. Information regarding Java is described in the reference by David Flanagan, “Java in a Nutshell: A Desktop Quick Reference,” 2d edition, 1997 (ISBN 1-56592-262-X), which is hereby incorporated by reference.
In accordance with one embodiment, a developer extends the DhDocument class. The DhDocument-derived class is instantiated by a DhModule class that is placed in the HTML stream. The DhModule class ensures that a Java object can connect to an HTML document container. The HTML container refers to a documentLoad method as the entry point into the Java object. Once the documentLoad method is called by the HTML container, the DhDocument class enables a Java developer to manipulate a HTML page, and its contents.
CONCLUSION
The present invention provides software developers who program in Java the ability to translate Java programs into a tag-based display language such as HTML. The tag-based display language generated from a single Java program can be tailored to a variety of different browsers. In one embodiment, the tag-based display language is tailored for Internet Explorer version 4.0.
In other embodiments, other object-oriented programs may be similarly converted to a desired tag-based procedural programming language or script. In an object-oriented programming environment, it is a simple matter to write programs which can be easily “plugged in” as desired to perform specialized conversions. Programs written in C++, Java, Smalltalk and others can be converted to any tag-based format, such as DHTML, HTML and XML for dynamic display and storage. Additional or varied states may also be employed without departing from the invention.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiments shown. This application is intended to cover any adaptations or variations of the present invention.
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An HTML package of the Windows foundation classes framework allows Java developers to write Java code normally as if they were writing to any user interface framework. The WFC framework converts their coding into standard HTML for display on an Internet Explorer version 4.0 web browser, a selected browser or generic HTML if so indicated by the developer. The HTML generation process is replaceable with third party generators to specifically target selected browsers with differing capabilities. During code writing key value pairs are maintained in arrays and are used to generate styles and attributes, which are further used to generate HTML. Also, several states are used when the code is being written to manage modification and display of HTML directly on a browser. The states and movement between them are transparent to the programmer because the states are handled internally by the library.
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PRIORITY
[0001] This application claims priority of U.S. provisional patent application No. 60/541,876 filed on Feb. 4 th 2004.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field of the Invention
[0003] The present invention relates to sport and fashion accessories and entertainment devices, more particularly to pompons.
[0004] 2. Background of the Invention
[0005] Pompons are customarily used as accessories in cheerleading. A common practice is that the cheerleaders and fans hold the pompon accessories in hand. This practice however, has the disadvantage that holding the pompon limits the freedom of movements of the hands. Another disadvantage of the common hand held pompons is that they cannot be attached to any other body part but need to be held in hand. A still another disadvantage is that when fans put the pompons down, they tend to forget them and leave them behind after the event is over.
[0006] U.S. Pat. No. 5,234,725 discloses a wrist pompon structure. The basic idea of this invention is an elastomeric tubular sleeve having a forward annular end wherein an annular array of elongate, flexible tassel webs are secured. The advantage of this invention is that the cheerleader does not need to hold the pompon in her hand. This invention however, is rather elaborate in use as the whole sleeve has to be taken off when the pompons are not used anymore. Neither does this invention give a chance to use the pompons in any other body part than hands. Nor does this invention allow use of pompons of different structures.
[0007] U.S. Pat. No. 6,340,507 discloses a self-securing pompon. This pompon structure consists of a loop such that a body part may be placed through the loop and so secured to the person. This invention makes it possible to secure the pompon to for example finger, hand or ankle—i.e. to such body parts that allow one to put the body part through the loop, but not anywhere else. Another disadvantage of the invention according to this disclosure is that the loop of the pompon may become loose and eventually the holder has anyway to hold the pompon loop with her hand.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 . Is a representation of a preferred embodiment where the pompon structure 1 is attached on a mitten (garment 7 ) with hook and loop fastener such as VELCRO.
[0009] FIG. 2A is a schematic drawing showing a fastener strip 2 attached to a muff (garment 7 ) and a pompom 1 secured to the muff by attaching the hook (rough) side 5 of one end of the strip to the loop(soft) side 4 of the other end of the strip thereby forming a loop 6 to secure the pompon.
[0010] FIG. 2B is a representation of an embodiment where pompon 1 is attached to a mitten (garment 7 ) by wrapping the hook and loop fastener strip 2 around the pompon thereby forming a loop 6 around the pompon.
[0011] FIG. 3 represents the structure of a single hook and loop fastener strip 2 . The strip is formed from a hook strip and a loop strip. In this embodiment the loop (soft) 4 and hook (rough) 5 sides of the fastener strip are facing different directions. The strip is attached to the garment 7 from its midpoint 8 where the two strips are overlapping each other so that the non adhesive sides 3 are facing each other.
[0012] FIG. 4A shows an embodiment where two fastener strips are attached to both sides of the tip of a hat (garment 7 ). The loop (soft) side 4 and the hook (rough) side 5 of the strips face the same direction. In this particular example the hook side strip is longer than the loop side strip; therefore a pompon shall be attached to the garment by wrapping the shorter loop side strip around the pompon and attaching the hook side strip to the shorter loop side strip.
[0013] FIG. 4B shows the ends of two fastener strips attached together thereby forming a loop 6 . The strips, when separated, can be wrapped around the center of the pompon to hold the pompon securely in the loop.
[0014] FIG. 4C is a representation of an embodiment where the pompon structure 1 is attached on a hat (garment 7 ) with the fastener strip wrapping around the center of the pompon.
[0015] FIG. 5A is a representation of an embodiment where pompons 1 are attached to both ends of a scarf (garment 7 ).
[0016] FIG. 5B shows the fastener loop 6 on one end of a scarf (garment 7 ) and a pompon 1 attached to another fastener loop on the second end of the scarf.
[0017] FIG. 6 represents an alternative embodiment where the pieces of clothing (garment 7 ) include slits 9 through which the fastener strip 2 can be slid. In this embodiment the strip is formed by attaching a strip having loop (soft) side 4 to another strip having hook (rough) side 5 so that the non adhesive sides 3 face the same direction and the strips are sewn together from the overlapping midpoint 8 .
[0018] FIG. 7A represents an alternative embodiment where the pompon 1 is secured to a claw clip 10 with which the pompon can be attached to a desired object.
[0019] FIG. 7B . Shows attachment of a pompon 1 to a claw clip 10 with an elastic band 11 .
[0020] FIG. 8 represents and alternative embodiment where the pompon 1 is secured to a clip 10 and is used as an earring.
[0021] FIG. 9 shows an alternative embodiment where the pompon 1 is secured to a clip 10 and the clip is further attached to an earring.
[0022] FIG. 10 shows an alternative embodiment where the pompon 1 is attached to shoes (garment 7 ) with a clip 10 .
[0023] FIG. 11 shows an alternative embodiment where the pompon 1 is attached with a clip 10 to a garment 7 here being a coat or a purse.
[0024] FIG. 12 shows an alternative embodiment where the pompon 1 is attached to a garment 7 (hat) or hair with a clip 10 .
[0025] FIG. 13 shows an alternative embodiment where the pompon 1 is attached to a garment 7 (visor) with a clip 10 .
[0026] FIG. 14 shows an embodiment where the pompon 1 is attached to a keychain with a clip 10 .
DETAILED DESCRIPTION OF THE INVENTION
Preferred Embodiment of the Invention
[0027] The present invention is an attachable and/or removable pompon structure. The pompon structure comprises a pompon 1 and a fastener 2 for securing the pompon for example on a clothing article, any other article or even on the body parts of the user. According to one preferred embodiment the fastener consists of two strips of adhesive fabric, such as hook and loop fastener commonly sold under the name VELCRO, but not limited to that. The strips are sewn together from the ends of the strips so that non-adhesive sides 3 of the fastener strips are overlapping, thereby forming one strip that has the loop side 4 (soft side) on the top of one end and the hook side 5 (rough side) on the bottom of the other end. ( FIG. 3 ). The strip is attached to a garment 7 , such as mitten or muff, by sewing it from its midpoint 8 on to the cloth or other object. The strip is wrapped around the pompon and the rough end of the strip is fastened on the soft end of the strip ( FIGS. 2A and 2B ).
[0028] Alternatively the two fastener strips can be sewn separately on a garment such as a hat or a scarf. ( FIGS. 4A , B, C and 5 A and B). In this alternative embodiment the rough side 5 of one strip faces same direction as the soft side 4 of the other strip (shown in FIG. 4A ). In this embodiment one of the strips may be longer than the other one and it is attached to the shorter strip while wrapping the pompon securely in to the loop 6 formed by the strips ( FIGS. 4B and 5B ).
[0029] According to still another embodiment a fastener strip is formed of two strips so that the final fastener strip 2 has rough and soft sides facing same direction (shown in FIG. 6 ). The strip 2 is attached on a garment 7 by sliding it through a slit 9 in the garment or another object where the pompon is to be attached ( FIG. 6 ). A pompon is secured into the loop formed when the rough and the soft ends of the strip are attached together.
[0030] The pompon can be attached with the fastener for example on the backside of a glove or a mitten or a visor; smaller pompons can be attached on the fingers of the gloves or mittens. Alternatively, the pompon can be attached on socks, hats, sleeves or anywhere else in a costume. The pompons can even be attached on bags, muffs and scarves.
[0031] According to another preferred embodiment the fastener is a clip 10 . According to this embodiment the pompon may be secured to the clip with an elastic band 11 or other comparable method. This embodiment is shown in FIGS. 7A and 7B . The pompon may even be glued to the clip. According to this embodiment the clip wherein the pompon is attached to is further attached to any desired object such as a piece of clothing ( FIG. 11 ) for example to shoes ( FIG. 10 ), or any other object such as an earring ( FIGS. 8 and 9 ), a key chain ( FIG. 14 ), a refrigerator magnet, figurines or to hair ( FIG. 12 ). The clip may be any regular plastic clip. The clip can be a claw or clamp clip or it can as well be a two part clip consisting of male and female parts. The pompons can be alternatively attached to other attachment means such as hooks.
[0032] The various alternatives give a chance also for the public to wear or use the pompons of their favorite team and still have their hands free. The pompon structures can easily and quickly be removed and attached to another garment or objective.
[0033] The advantage of the present invention is that the pompon structure leaves the hands of the user free, thereby giving the user more freedom to move. A further advantage of the invention is that the pompons can be attached anywhere in the garment, not only to hands or feet. A still further advantage of the invention is that the pompon structures can be made to be of any size and be attached practically anywhere in the garment or other objects. Still another advantage of the present invention is that the removable pompons allow user to mix and match pompon colors as desired. Further advantage is that removable pompons allow for laundering of clothing articles. A still further advantage of the present invention is that the attachment of the pompon either by wrapping the fastener strip completely around the center of the pompon or by attaching the pompon on a clip which is further attached to an object is secure and does not allow the pompon to fall off when being shaken. Further advantage of the present invention is that fans will not put pompons down and forget them when the event is over. A still another advantage of the invention is that the items according to the present disclosure are multifunctional. For example, one can use the garments as such and the pompons as such, or attach the pompons onto the garments.
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The present disclosure is related to pompons. The disclosure describes pompon structures enabling attachment of the pompon practically onto any object including various garments and clothing articles, but also objects such as earrings. The user can easily move the attached pompon. The disclosure describes a useful pompon structure that leaves the hands of the user free but enables attachment of the pompons securely.
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This application is a division of U.S. patent application Ser. No. 09/497,805, filed Feb. 3, 2000, which claims the benefit, under 35 U.S.C. §119(e) of U.S. Provisional applications No. 60/118,458, filed on Feb. 3, 1999, and No. 60/134,759, filed May 18, 1999.
FIELD OF THE INVENTION
The present invention relates to a process for the preparation of pravastatin, and particularly to a microbial process for the manufacture of pravastatin on an industrial scale.
BACKGROUND OF THE INVENTION
The highest risk factor of atherosclerosis and especially coronary occlusion is the high cholesterol level of the plasma. In the last two decades 3-hydroxy-3-methylglutaryl coenzyme A reductase (EC.1.1.1.34) as the rate limiting key enzyme of the cholesterol biosynthesis was extensively examined. Pravastatin, a compound of Formula I,
and other related compounds (compactin, mevinolin, simvastatin) are the competitive inhibitors of the HMG-CoA reductase enzyme [A. Endo et al., J. Antibiot. 29, 1346-1348 (1976); A. Endo et al., FEBS Lett. 72, 323-326 (1976); C. H. Kuo et al., J. Org. Chem. 48, 1991 (1983)].
Pravastatin was first isolated by M. Tanaka et al. (unpublished results) from the urine of a dog during the examination of the compactin metabolism (Arai, M. et al., Sankyo Kenkyusyo Nenpo, 40, 1-38, 1988). Currently pravastatin is a cholesterol lowering agent with the most advantageous action mechanism in the therapy. Its most important character is tissue selectivity, i.e., it inhibits the cholesterol synthesis at the two main sites of the cholesterogenesis, such as in the liver and in the small intestine, while in other organs the intracellular enzyme limiting effect is hardly detectable, At the same time the cholesterol biosynthesis limiting effect of mevinolin and simvastatin is significant in most of the organs (T. Koga et al., Biochim. Biophys. Acta, 1045, 115-120, 1990).
Pravastatin essentially differs in chemical structure from mevinolin and simvastatin which have more lipophilic character. In the case of the latter compounds the substituent connected to the C-1 carbon atom of the hexahydronaphthalene skeleton is ended in a 6-membered lactone ring, while in the case of pravastatin, instead of the lactone ring, the biologically active, opened dihydroxy acid sodium salt form is present. Another important structural difference is that instead of the methyl group of mevinolin and simvastatin at the C-6-position of the hexahydronaphthalene ring, a hydroxyl group can be found in pravastatin, which results in a further increase in its hydrophilic character.
As a result of the above structural differences pravastatin is able to penetrate through the lipophilic membrane of the peripheral cells only to a minimal extent (A. T. M., Serajuddin et al., J. Pharm. Sci. 80, 830-834, 1991).
Industrial production of pravastatin can be achieved by two fermentation processes. In the first, microbiological stage compactin is prepared, then in the course of a second fermentation the sodium salt of compactin acid as a substrate is converted to pravastatin by microbial hydroxylation at the 6β-position.
According to published patents, the microbial hydroxylation of compactin can be accomplished to various extents with mold species belonging to different genera, and with filamentous bacteria belonging to the Nocardia genus, with Actinomadura and Streptomyces genera (Belgian patent specification No. 895090, Japanese patent specification No. 5,810,572, U.S. Pat. Nos. 4,537,859 and 4,346,227 and published European patent application No. 0605230). The bioconversion of compactin substrate was published in a 500 μg/ml concentration using filamentous molds such as Mucor hiemalis, Syncephalastrum nigricans, Cunninghamella echinulata and in 2000-4000 μg/ml with Nocardia, Actinomodura and Streptomyces strains belonging to the prokaryotes.
A general problem experienced in the cases of manufacturing the pravastatin with filamentous molds is that due to the antifingal effect of compactin, the microorganisms are not able to tolerate the compactin substrate fed to the culture even at low concentrations (Serizawa et al., J. Antibiotics, 36, 887-891, 1983). The cell toxicity of this substrate was also observed in the hydroxylation with Streptomyces carbophilus extensively studied by Japanese researchers (M. Hosobuchi et al., Biotechnology and Bioengineering, 42, 815-820, 1993).
Japanese authors tried to improve the hydroxylating ability of the Streptomyces carbophilus strain with recombinant DNA techniques. A cytochrome P-450 monooxygenase system is needed for the hydroxylation of compactin (Matsuoka et al., Eur. J. Biochem. 184, 707-713, 1989). However, according to the authors, in the bacterial cytochrome P-450 monooxygenase system not one but several proteins act in the electron transport, which aggravate the application of the DNA techniques. Development of a cost-effective microbiological hydroxylation method for the manufacture of pravastatin is an extremely difficult, complex task.
The aim of the present invention is to elaborate a new microbial process for the preparation of pravastatin from compactin in industrial scale, which would produce pravastatin at more advantageous conditions than those previously known. During our research work, above all we tried to find a microorganism strain with a hydroxylase enzyme that can be adapted for the microbial transformation of compactin to pravastatin in a high concentration.
SUMMARY OF THE INVENTION
The present invention relates to a microbial process for the preparation of the compound of formula (I)
from a substrate compound of formula (II),
wherein R stands for an alkali metal or ammonium ion, comprising the steps of (a) cultivating a strain of Mortierella maculata filamentous mold species able to 6β-hydroxylate a compound of formula (II) on a nutrient medium containing assimilable carbon- and nitrogen sources and mineral salts, (b) feeding the substrate to be transformed into the developed culture of Mortierella maculata , (c) fermenting the substrate until the end of bioconversion, (d) separating the compound of formula (I) from the culture broth, and (e) isolating the compound of formula (I).
The present invention also relates to a biologically pure culture of the Mortierella maculata n. sp. E-97 strain deposited at the National Collection of Agricultural and Industrial Microorganisms, Budapest, Hungary under accession number NCAIM(P)F 001266 and a biologically pure culture of its mutant, the Mortierella maculata n. sp. E-97/15/13 strain deposited at the National Collection of Agricultural and Industrial Microorganisms, Budapest, Hungary under accession number NCAIM(P)F 001267.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is an illustration of the physical characteristics of Mortierella maculata n. sp. E-97.
DETAILED DESCRIPTION OF THE INVENTION
In the course of our screening program, which covered about 5500 prokaryotic and eukaryotic strains, 23 microorganisms were selected, which were able to hydroxylate compactin in opposition. Among these strains a filamentous mold proved to be more appropriate for the production of pravastatin due to its higher resistance against compactin as compared to the strains known from published patents. According to the taxonomic investigation, this strain proved to be a new representative of the species belonging to the Mortierella genus ( Mortierella maculata n. sp.). From the selected molds a new strain was isolated on the one hand by the application of the mutation-selection methods, and on the other hand by the induction of the hydroxylase enzyme of the strain, which one was able to hydroxylate the compactin substrate to pravastatin in a higher concentration than published so far. As mutagenic agents, physical and chemical mutagens were applied (UV irradiation, methyl methane sulfonate, N-methyl-N′-nitro-N-nitrosoguanidine). After the mutagenic treatments, in order to prepare haploid cells, the spore suspension was spread on benomyl-containing agar plates, then in order to induce the hydroxylase enzyme the developed colonies were inoculated onto 100 μg/ml 8-de-(2-methyl-butyryl)-compactin-containing or compactin-containing agar plates. By the application of these methods a mutant strain was prepared from the new strain that is able to convert compactin to pravastatin to a significantly higher extent than the parent strain.
In the course of the optimizing experiments we determined the composition of the most beneficial inoculum, and the most advantageous bioconversion media for the compactin hydroxylation, as well as the optimal method for the repeated feeding of compactin in a high concentration.
Consequently, this invention is based on the recognition that the E-97 and E-97/15/13 designated strains of the isolated mold named Mortierella maculata , which were deposited under accession numbers of NCAIM(P)F 001266 and NCAIM(P)F 001267 respectively, at the National Collection of Agricultural and Industrial Microorganisms (Department of Microbiology and Biotechnology, University of Horticulture and the Food Industry Budapest), under appropriate fermentation conditions are able to manufacture pravastatin to a high extent, while the undesired related compounds such as the acid forms of 6α-hydroxy-compactin, 2α-hydroxy-compactin, 8-de-(2-methyl-butyryl)-compactin, 3α,5β-dihydroxy-5,6-dihydro-isocompactin, 8a,β-hydroxy-compactin and the hydroxylated derivatives at positions 2 and 3 of the 2-methyl-butyryl side chain of compactin are obtained only in small or trace amounts during the bioconversion. Thus, these strains are especially appropriate for manufacturing pravastatin in an industrial scale.
Taking into account that the economical manufacture of the active ingredient on an industrial scale is a function of the compactin substrate concentration, it is important to have a strain that is able to tolerate high compactin and pravastatin concentrations. Consequently, a further important part of the invention is the recognition that the hydroxylating ability of the original mold isolate can be improved by the application of mutation-selection and enzyme induction methods and, furthermore, that by the development of an appropriate method for substrate feeding the hydroxylation of large quantities of compactin to pravastatin can be executed in a single procedure. In conclusion, the new mutant strain designated as Mortierella maculata n. sp. E-97/15/13 is especially appropriate for the manufacture of pravastatin.
Taxonomic features of the isolated new mold species comparing it to the most important diagnostic attributes of the known Mortierella species are summarized below.
Taxonomic description of the holotype strain Mortierella maculata nov. spec. E-97
On starch-casein-malt extract-agar media the aerial mycelium is well developed (more than 10 μm thick covering layer over the substrate mycelium). At the beginning it appears as a tightly woven white web of hyphae, in which later yellowish sporulating spots with a few mm diameter sparsely appear (new name “maculatus” refers to the above: spotted). This yellowish coloration can sometimes occupy the larger continuous surfaces of the aerial web. The color of the substrate mycelium is on Czapek-, bloody-Czapek-, tyrosine-, starch-casein-, malt extract-, etc. agar media mostly colorless or light yellowish. The color of the substrate mycelial web is light reddish on yeast extract-glucose-peptone medium. Production of diffusible and soluble pigments on the above listed media is not experienced, or only rarely an insignificant yellowish coloration occurs on these media. Colonies of strain E-97, due to their volatile oil production and similarly to many other species of Mortierella, (except to species of section Isabellina), can exude a very characteristic strong scent.
Sporangiophores, designated by reference numerals 1 - 7 in FIG. 1, frequently develop locally on the aerial hyphae (but less on the substrate ones) in great numbers at very different distances from each other. They are not branching, but are mostly straight or curved. Their length is generally between 60-80 μm. The starting point in the overwhelming majority of cases is a more or less short but strongly swollen hyphal section of the aerial web, from which they are separated by walls. Sporangiophores themselves can be also swollen (sometimes strongly), as shown by reference numeral 6 , but in the direction of the sporangium they gradually narrow, from 5.0-9.0 μm to 1.0-2.0 μm. It is an important taxonomic character that below the sporangiophores they never broaden out (see reference numeral 8 ).
Sporangia are spherical; in some cases slightly flattened spheres. Their diameter is about 6.0-17.0 μm, relatively small compared to the measures of sporangia of other Mortierella species. Sporangia may contain many spores, but sporangia bearing only one spore also exist. The spores 9 are cylindrical or less oval. Their size is 3.0-5.0×1.5-2.0 μm. Within the individual spores one or two small dark spherical oil-drops 10 may be present. Due to the very easy disintegration of the wall of sporangia, in wet surroundings the spores will quickly be scattered. After the disintegration of the sporangium, sometimes at the end of the sporangiospores, a fine pitchfork-like “collar” and a very short rudimental (and not typical) columella can be observed. Gemmae 15 - 28 that are spherical or cylindrical may occur on most different diagnostic media. Usually the size is 10-25 μm. In the cultures chains of spherical gemmae 13 , budding cells, intercalated gemmae 15 - 23 , hyphal associations of particular spiral-growth of one hypha around the other 11 , anastomotic-like structures and giant cells, etc. can also be found. In the aerial mycelium also large (50-250 pm diameter) very dense hyphal webs 14 can be seen but without the presence of detectable zygotes.
Cultures of strain E-97 are able to reduce nitrates to nitrites, do not hydrolyze starch, esculin, arginine or gelatine but hydrolyze Tween polysorbates and do not decompose paraffin hydrocarbons. The cultures of strain E-97 have urease activity show a good growth between pH 7.0 and 9.0 tolerate a maximum 2% NaCl. The effect of xanthine, hypoxanthine, lecithin, tyrosine and adenine are negative. A strong acid production of the cultures has been detected from glucose, fructose, glycerine and galactose, but very weak or no production from xylose, arabinose, raffinose, sorbitol, inositol, inulin, etc. Weak growth is detected on pyruvate and acetate but no growth could be found with benzoate, salicylate, citrate, lactate, succinate, tartarate and malonate. A good growth was observed with glucose and fructose as sole carbon-sources in the medium. Utilization tests with xylose, arabinose, rhamnose, sucrose, raffinose, mannitol and inositol proved to be negative. The cultures do not decompose cellulose.
Systematic position
Strain E-97 belongs to the family Mortierellaceae and it is a typical member of the genus Mortierella: sporangia contain generally many spores, columella is extremely reduced, gemmae are frequently present, the occurrence of zygotes has not been detected and the colonies exude a very characteristic strong scent. Within the genus Mortierella, strain E-97 is a typical representative of the “Section Alpina.” The latter can be characterized by very short non-branching sporangiophores (maximal length to 200 μm), and minute sporangia (Zycha, H. und Siepmann, R, Mucorales. Eine Beschreibung aller Gattungen und Arten dieser Pilzgruppe. D-3301 Lehre, Verl. von J. Cramer. 1969). Among the members of the section Alpina, strain E-97 shows the greatest similarity to the species M. thaxteri Bjorling 1936 and M. renispora Dixon-Stewart 1932. However, the data in the Table I clearly show the differences in diagnostic properties of strain E-97 and of these two species. Accordingly, as a new species herewith we introduce the strain under the name Mortierella maculata nov. spec. E-97.
TABLE 1
A comparison of the holotype strain E-97 of Mortierella maculata n.sp.
with the species M. renispora and M. thaxteri on the basis of key diagnostic properties
Mortierella renispora
Mortierella strain E-97
Mortierella thaxteri
Origin of
Ordinary, however the
Laterally from (swollen or
Laterally from swollen separated
sporangiophores
hyphae are wider than the
normal) aerial hyphae or not
segments of aerial hyphae or not
regular ones, laterally from
separated sections of substrate
separated segments of substrate hyphae
broadened swollen hyphae.
hyphae.
Shape and size of
Gradually decreasing towards
Mostly straight or curved, not
Length about 60-90 μm. Width at the
sporangiophores
the top from 10 μm to 3 μm.
branching. Width gradually
starting point is about 5-7 μm, at the tip
Length is about 200 μm.
decreasing towards the tip:
it is reduced to 1.5-2 μm. Immediately
from 5-9 μm to 1.5-2.5 μm.
under the sporangium broadened out
Length is about 60-80 μm. At
the tip never broadened.
Shape and size of
Colorless, diameter is 25 μm.
Mostly spherical (6-17 μm
Spherical (12-20 μm diam.). They
sporangia
diam.) but rarely less flattened.
contain many spores but on certain
Generally contain many
media there is also only one spore-
spores, rarely one spore.
bearing sporangra.
Wall (membrane)
Spreading membrane. After
Disintegrating. A pitchfork-
Disintegrating, a minute backward-
of the sporangia
disintegration remains a
like collar remains,
bending collar remains.
collar-like structure.
Shape and size of
Roughly kidney-shaped.
Cylindrical. Length (3-5 μm)
Ellipsoidal hyaline spores of 3.5-4 ×
the spores
hyaline structures, sizes are
can doubly exceed the width
1.5-2 μm) dimension.
2 × 4 μm.
(1.5-2 μm).
Gemmae
Occur on the most different
Frequent on very different
Intercalary, oval gemmae (10-14 μm) in
media
media, mostly in the aerial
the substrate mycelium.
mycelium. Spherical or
elongated (10-25 μm).
Zygotes
Frequent on all diagnostic
Not detected.
Not observed.
media. Diameter together
with the covering hyphae is
about 500 μm, without them
about 30 μm.
Dense foci of the
Large densely woven hyphal
In old cultures large (100-125 μm
hyphal web
foci (50-250 μm) frequent but
diam) yellowish-grey dense hyphal
without zygotes.
webs, without zygote.
Color and habit of
Loose, always white hyphal
White with yellowish spots.
At first spider's web-like, later more
the aerial mycelium
web
dense.
In the process for the preparation of pravastatin according to the present invention, preferably the culture of the mold strain designated as Mortierella maculata n. sp. E-97 or its mutant designated as E-97/15/13 is used. The selected strain is highly advantageous due to its fast growth. As a carbon source it easily utilizes glucose, glycerine, fructose, or galactose. As a nitrogen source yeast extract, peptone, casein, meat extract, soybean meal, corn steep liquor, sodium nitrate, or ammonium sulfate can be used.
In the culture media used for the production of pravastatin besides the above carbon and nitrogen sources mineral salts, e.g., potassium dihydrogen phosphate, magnesium chloride, magnesium sulfate, trace elements (ferrous, manganous salts), amino acids and antifoaming agents, can be present.
According to a preferred embodiment of the present invention, the spore suspension having been prepared from the slant agar culture of the Mortierella maculata n. sp. designated as E-97 strain or its mutant [NCAIM(P)F 001267] designated as E-97/15/13, is seeded into an inoculum medium; then 10% of the inoculum culture, which is cultivated for 3 days at about 25-30° C., preferably at about 24-28° C., most preferably at about 28° C., is transferred into the bioconversion medium. Then it is incubated for 4 days at about 25-28° C., preferably at about 28° C., then glucose and the sodium salt of compactin acid are fed into the culture. Depending on the concentration of the fed compactin substrate, the cultivation is continued for 2-12 days further under aerobic conditions, while the pH is maintained between 5.5 and 7.5, preferably at 7.0. The bioconversion is done under stirred and aerated conditions, when the air flow rate is 0.2 vvm, the spinning rate of the stirrer is 400/min.
In the course of the fermentation the bioconversion of compactin substrate was followed by a high pressure liquid chromatographic method (HPLC). According to this method, the sample of the broth is diluted twofold with methanol and centrifuged, and the supernatant is used for the HPLC analysis under the following parameters: Waters analytical HPLC equipment; column: Nucleosil C 18 10 μm; detection wavelength: 238 nm; injection volume: 20 μl, flow rate: 1 ml/min; gradient elution is used, eluents: A=0.05% aqueous solution of phosphoric acid, B=acetonitrile.
Elution gradient:
Time (min)
Eluent A (%)
Eluent B (%)
0
70
30
20
0
100
25
0
100
25.1
70
30
35
70
30
Approximate retention times: pravastatin 8.6-9.0 min; compactin acid 11.6-12.0 min; pravastatin lactone 15.0-15.5 min, compactin 16.5-17.0 min.
For the production of pravastatin the aqueous solution of the sodium salt of compactin acid is added at the 96th hour of the cultivation. For this procedure the substrate is prepared in solid form as follows. Compactin lactone is hydrolyzed in a 0.2M sodium hydroxide solution for 2 hours at 40° C. then the pH of a reaction mixture is adjusted to 7.5 by hydrochloric acid and the neutralized solution is layered on a Diaion HP-20 adsorbent column; the sodium chloride formed during the neutralization is eliminated by aqueous washing of the column, and then the sodium salt of the compactin acid is eluted from the column by 50% aqueous acetone. Thereafter the eluate is distilled in vacuum and the aqueous residue is lyophilized. After neutralization the aqueous solution of the alkaline hydrolysate of compactin can also be directly used as substrate. In this case the compactin acid sodium salt content of the hydrolysate is measured by HPLC, and the solution is kept at −20° C. until being applied.
The higher the broth pH reached by the fourth day of the fermentation, the more advantageous for the hydroxilation of the compactin substrate. Feeding of the compactin substrate is allowed to be started when the pH of the broth exceeds 6.3. At the 4th day of the fermentation as much of the sterile filtered aqueous solution of compactin acid sodium salt is added as needed to reach the 500 μg/ml concentration. Glucose is also fed to the culture from its 50% solution sterilized at 121° C. for 25 minutes as follows: if the pH of the broth is higher than 6.7 value, 1% glucose is added related to the volume of the broth, while if the pH is within the 6.3-6.7 range the quantity of the glucose fed is 0.5% Compactin acid sodium salt is consumed from the broth after 24 hours, its transformation is analyzed by HPLC measurement. In this case, for each ml of the broth another 500 μg of compactin is added. Besides the compactin substrate, glucose is also fed as described above. Morphology of the 120 hour culture is characterized by the small pellet growth (diameter of the pellet; 0.5-3.0 mm). After 24 hours the second dose of substrate is also consumed from the broth, thus a further portion of compactin acid sodium salt producing a 500 μg/ml concentration of it in the whole broth is added parallel with the glucose feeding dependent on the pH value of the broth. From the 4th day of the fermentation the substrate and the glucose feeding is repeated in daily frequency as it is written before until the 17th-18th day of the fermentation.
For the recovery of the product from the broth, it is advantageous to take into consideration the fact that during the bioconversion pravastatin is formed in its acidic form, thus it can be isolated from the filtrate of the broth by its adsorption on an anion exchange resin column. For the isolation of the product it is advantageous to use a strongly basic anion exchange resin which is a polystyrene-divinylbenzene polymer carrying quaternary ammonium active groups. The product can be adsorbed directly from the filtrate of the broth by mixing the anion exchange resin being in hydroxyl form into it. The product being adsorbed on the ion exchange resin can be eluted from the column by acetic acid or a sodium chloride-containing acetone-water mixture, preferably 1% sodium chloride containing acetone-water (1:1) mixture. Pravastatin-containing fractions are combined and the acetone being in the eluate is distilled off in vacuum. The pH of the concentrate is adjusted with 15% sulfuric acid into the range of 3.5-4.0 and the aqueous solution is extracted by ethyl acetate. The ethyl acetate extract is washed with water and dried with anhydrous sodium sulphate. Then the lactone derivative is prepared from pravastatin. The lactone ring closure is carried out in dried ethyl acetate solution at room temperature, under continuous stirring by inducing the lactone formation with trifluoroacetic acid being present in catalytic quantity. The transformation procedure is checked by thin layer chromatographic analysis (TLC). After finishing the lactone formation the ethyl acetate solution is washed at first with 5% aqueous sodium hydrogen carbonate solution and then with water, then it is dried with anhydrous sodium sulfate and evaporated in vacuum. The evaporated residue is treated in acetone solution with charcoal, then evaporated again and recrystallized from a 1-4 carbon atom-containing aliphatic alcohol, preferably from ethanol. The evaporation residue of the recrystallization mother liquor is purified with silica gel column chromatography applying the mixture of ethyl acetate-n-hexane with gradually increasing ethyl acetate content as the eluent.
From the pravastatin lactone obtained after recrystallization and chromatographic purification pravastatin is prepared by hydrolysis at room temperature in acetone with equivalent quantity of sodium hydroxide. When the pravastatin sodium salt formation is completed, the reaction mixture is diluted with water and neutralized, and the acetone content is distilled in vacuum. Pravastatin is adsorbed from the obtained aqueous residue on a Diaion HP-20 resin-containing column, washed with deionized water and eluted from the column with an acetone-deionized water mixture. Then the pravastatin containing fractions are combined, the acetone content is distilled off and after the lyophilization of aqueous residue pravastatin can be obtained in high purity, which can be recrystallized from an ethyl acetate-ethanol mixture.
In the course of the procedure the whole quantity of pravastatin can be adsorbed. During the lactone closure of pravastatin 3α-hydroxy-iso-compactin and other by-products can also be formed. Although these latter reactions decrease the yield of the isolation but those compounds can be separated by the above-described purification method and consequently, pravastatin can be manufactured this way in a pharmaceutically acceptable quality.
After finishing the bioconversion pravastatin can be extracted either from the fermentation broth or from the filtrate obtained after the separation of the filamentous mold cells. Filamentous mold cells can be eliminated either by filtration or centrifugation; however, it is advantageous especially on an industrial scale to make a whole broth extraction. Before extraction the pH of either the fermentation broth or the filtrate of the broth is adjusted to 3.5-3.7 with a mineral acid preferably with diluted sulfuric acid. The extraction is done with an ester of acetic acid and a 24 carbon atom containing aliphatic alcohol, preferably with ethyl acetate or isobutyl acetate. Extraction steps should be done very quickly in order to avoid the formation of the lactone derivative from pravastatin at acidic pH.
From the organic solvent extract the pravastatin in acid form can be transferred as the sodium salt into the aqueous phase. For example, from an ethyl acetate extract pravastatin can be extracted by 1/10 and 1/20 volume ratio of 5% sodium hydrogen carbonate or weakly alkaline water (pH 7.5-8.0). It was found that pravastatin can be recovered in a pure form from the above-obtained alkaline aqueous extract by column chromatography with the application of a non-ionic adsorption resin. An advantageous method is to first remove the solvent dissolved in the aqueous phase by vacuum distillation from the alkaline aqueous extract, and then the aqueous extract is loaded on a Diaion HP-20 column.
Pravastatin sodium salt being adsorbed on the column is purified by elution increasing gradually the acetone content of the aqueous solutions, then the pravastatin-containing main fractions are combined and concentrated in vacuum. The aqueous concentrate is purified further by chromatography on another Diaion HP-20 column, obtaining an eluate containing pure pravastatin, from which after clarification with charcoal and lyophilization pravastatin can be obtained in a pharmaceutically acceptable quality.
This isolation procedure consists of fewer stages than the previous one, since the lactone formation of pravastatin and its hydrolysis are not involved in the procedure. During the isolation pravastatin is exposed to acidic condition for only a limited time, under which it is less stable than in neutral or alkaline solutions, consequently, during this isolation procedure artefacts are practically not formed.
Furthermore, it was found that the chromatography on Sephadex LH-20 Dextran gel (hydroxypropylated derivative) is advantageously used for purifying pravastatin. By application of this method pravastatin exceeding the purity of 99.5% (measured by HPLC) can be produced.
In the course of our experiments it has been recognized that from the organic solvent extract, preferably from the ethyl acetate or isobutyl acetate extract of the broth or the broth nitrate of the filamentous mold or the filamentous bacteria strains among them the Mortierella maculata n. sp. strain able to 6β-hydroxylate a compound of general formula (II), pravastatin can be precipitated as a crystalline salt with secondary amines. Further it was found that for the salt formation several secondary amines containing alkyl, cycloalkyl-, aralkyl- or aryl-substituents are appropriate. Expediently non-toxic secondary amines were selected among them, e.g., dioctylamine, dicyclohexylamine, dibenzylamine. The isolation of the organic secondary amine salt intermediates, e.g., the dibenzylamine salt was carried out by adding dibenzylamine in 1.5 equivalent quantity related to the pravastatin content of the extract, then the extract is concentrated by vacuum distillation to 5% of its original volume, then another quantity of dibenzylamine is added into the concentrate in 0.2 equivalent ratio. The crystalline dibenzylamine salt is precipitated from the concentrate. The crystalline crude product is filtered and dried in vacuum. Then it is clarified with charcoal and recrystallized in acetone.
In the procedure mentioned earlier in which the organic solvent extraction and the reextraction at alkaline pH are involved, the isolation method based on the secondary amine salt formation can be used also for the replacement of the column chromatographic purification. In this case it is advantageous to precipitate the pravastatin dibenzylamine salt from the isobutyl acetate extract obtained after the acidification of the alkaline aqueous extract.
Pravastatin organic secondary amine salts can be transformed to pravastatin by sodium hydroxide or a sodium alkoxide, preferably sodium ethoxide.
The transformation is detailed in the case of pravastatin dibenzylamine salt. The recrystallized dibenzylamine salt is suspended in an isobutyl acetate-water mixture, then equivalent quantity of sodium hydroxide is added in aqueous solution to the suspension by maintaining under stirring the pH in the range of 8.0-8.5. After disappearance of the suspension the phases are separated and the pravastatin-containing aqueous solution is washed twice with isobutyl acetate. The aqueous solution is clarified with activated carbon and lyophilized yielding pravastatin in a pharmaceutically acceptable quality.
One preferred method for the transformation of pravastatin dibenzylamine salt to pravastatin is to suspend the recrystallized dibenzylamine salt in ethanol, then equivalent quantity or small excess of sodium ethoxide is added under stirring to the suspension, then the reaction mixture is concentrated in vacuum and by adding acetone the pravastatin is precipitated in crystalline form from the concentrate.
Another preferred method for the transformation of pravastatin dibenzylamine salt to pravastatin is to dissolve the recrystallized dibenzylamine salt in ethyl acetate-ethanol mixture and by adding equivalent quantity or small excess of sodium hydroxide in ethanol to the solution pravastatin is precipitated.
The isolation of pravastatin via a secondary amine salt intermediate is a simpler procedure than any previously known isolation procedures. During the procedure artifacts are not formed, and the separation of pravastatin from the by-products of the bioconversion and from the various metabolic products biosynthesized by the hydroxylating microorganism can be solved without the application of any chromatographic methods.
The structures of pravastatin, pravastatin lactone and the isolated secondary amine salts of pravastatin have been proven by UV, IR, 1 H-NMR, 13 C-NMR and mass spectroscopic methods.
EXAMPLES
The invention will be more fully described and understood with reference to the following examples, which are given by way of illustration and are not intended to limit the scope of the invention in any way.
Example 1
A spore suspension was prepared with 5 ml of a 0.9% sodium chloride solution obtained from a 7-10 day old, malt extract-yeast extract agar slant culture of Mortierella maculata nov. spec. E-97 [NCAIM(P)F 001266] strain able to 6β-hydroxylate compactin and the suspension was used to inoculate 100 ml inoculum medium PI sterilized in a 500 ml Erlenmeyer flask.
Composition of the medium PI:
glucose
50 g
soybean meal
20 g
in 1000 ml tap water.
Before the sterilization the pH of the medium was adjusted to 7.0, then it was sterilized at 121° C. for 25 min. The culture was shaken on a rotary shaker (250 rpm, 2.5 cm amplitude) for 3 days at 28° C., then 10 ml of the obtained culture was transferred into 100-100 ml bioconversion media MU/4 sterilized in 500 ml Erlenmeyer flask for 25 min at 121° C.
Composition of the medium MU/4:
glucose
40 g
soybean meal
20 g
casein-peptone
1 g
asparagine
2 g
potassium dihydrogen phosphate
0.5 g
in 1000 ml tap-water.
Before the sterilization the pH of the medium was adjusted to 7.0, then it was sterilized at 121° C. for 25 min.
Flasks were shaken on a rotary shaker (250 rpm, 2.5 cm amplitude) for 4 days at 25° C., then 50-50 mg compactin substrate (compactin acid sodium salt) was added in sterile-filtered aqueous form into the cultures, then the cultivation was continued. Similarly, at the 5th day another 50-50 mg compactin acid sodium salt was added into the mold cultures, and the fermentation was continued for a further 24 hours. The pravastatin content of the broth was determined by HPLC. The fermentation was continued for 168 hours. At the end of the bioconversion the average pravastatin concentration of the fermentation broth was 620 μg/ml.
Example 2
In a laboratory scale fermenter with 5 liters working volume a MU/S bioconversion culture medium is prepared, the components of the culture medium are added corresponding to 5 liters, volume but it was loaded up only to 4.5 liters, then it was sterilized for 45 min at 121° C. and seeded with 500 ml of the inoculum culture made according to the Example 1.
Composition of medium MU/8:
glucose
20 g
glycerine
20 g
soybean meal
20 g
peptone
5 g
potassium dihydrogen phosphate
0.5 g
polypropyleneglycol 2000
1 g
in 1000 ml tap water.
Before sterilization the pH of the medium was adjusted to 7.0 value.
The fermentation was carried out at 28° C., with a stirring rate of 400 rpm and with an aeration rate from bottom direction 60 liters/hour for 4 days. At the 2nd day after the transfer the culture started to foam heavily, which can be decreased by the addition of further polypropyleneglycol 2000. At the beginning of the fermentation (16-20 hours) the pH decreased from the initial value of 6.5 to 5.0-5.5, then from the 3rd day it started to increase and reached 6.3-7.5 by the 4th day. The feeding of the compactin substrate is allowed to be started if the pH of the broth is above 6.3. At the 4th day of the fermentation 2.5 g compactin substrate is added in sterile filtered aqueous solution. Calculated for the volume of the broth 0.5-1.0% glucose was added into the culture depending on the pH in the form of 50% solution sterilized at 121° C. for 25 minutes in parallel with the substrate feeding. After 24 hours the compactin substrate is consumed from the culture, which is detected by HPLC from the samples taken from the fermenter. In this case another 2.5 g compactin substrate and glucose were added as described above, and the bioconversion was continued for 24 hours further when the substrate was converted to pravastatin.
After finishing the fermentation, 5.1 liters broth containing 630 μg/ml pravastatin were filtered on a filter cloth. Two liters water were added to the separated mycelium, then the mycelium suspension was stirred for one hour and filtered. These two filtrates were combined and passed through with a flow rate of 500 ml/hour on a column containing 138 g (250 ml) Dowex Al 400 (OH) resin (diameter of the column 3.4 cm, height of the resin bed: 28 cm), then the resin bed was washed with 300 ml deionized water. Subsequently, the elution from the resin was carried out by 1 liter acetone-water (1:1) mixture containing 10 g sodium chloride. The volume of the fractions was 100 ml each. The eluate was analyzed by the following thin layer chromatographic (TLC) method: adsorbent: Kieselgel 60 F 254 DC (Merck) aluminum foil; developing solvent: acetone-benzene-acetic acid (50:50:3) mixture; detection: with phosphomolybdic acid reagent. The R f value of pravastatin is 0.5. Fractions containing the product were combined and the acetone was distilled off in vacuum. The pH of the 400 ml concentrate was adjusted to 3.5-4.0 by 15% sulfuric acid, then it was extracted three times by 150 ml ethyl acetate. The ethyl acetate extracts were combined and dried with anhydrous sodium sulfate. Subsequently, pravastatin lactone was prepared from pravastatin acid by adding at room temperature under continuous stirring trifluoroacetic acid in catalytic amount. The formation of pravastatin lactone was controlled by TLC (the R f value of pravastatin lactone in the above TLC system is 0.7). After the completion of the lactone formation, the ethyl acetate was washed with 2×50 ml 5% aqueous sodium hydrogen carbonate solution, then washed with 50 ml water, dried with anhydrous sodium sulfate and evaporated in vacuum. The evaporation residue obtained in a quantity of 3 g was dissolved in 100 ml acetone and clarified with 0.3 g charcoal. Then the charcoal was filtered off and the acetone was evaporated in vacuum. The crude product obtained was crystallized from 20 ml ethanol. Precipitated crystalline pravastatin lactone was filtered off, and washed on the filter with 30 ml n-hexane and dried at room temperature in vacuum. In this way 1.5 g chromatographically pure pravastatin lactone was obtained. Melting point 140-142° C., [α] D =+194° (c=0.5, methanol). The mother liquor of the crystallization was evaporated in vacuum and 1.2 g evaporation residue is obtained, which was chromatographed on 24 g Kieselgel 60 adsorbent containing column (diameter of the column: 1.6 cm, height of the bed: 20 cm). The crude product dissolved in 5 ml benzene was layered on the column. For elution mixtures of ethyl acetate-n-hexane were used in which the ethyl acetate content was gradually increased. Pravastatin lactone can be eluted from the column with the mixture of 60% ethyl acetate −40% n-hexane. Fractions were controlled by TLC using the mixture of ethyl acetate-n-hexane (9:1) as the developing solvent. The pravastatin lactone-containing fractions were combined and evaporated in vacuum. According to this method 0.3 g pure product is obtained, its quality identical with that of the pravastatin lactone obtained by crystallization.
The two pravastatin lactone batches were combined and the sodium salt was prepared according to the following method: 1.8 g pravastatin lactone was dissolved in 20 ml acetone and under stirring 4.5 ml of IM aqueous sodium hydroxide was added, then the solution was stirred for half an hour at room temperature. When the salt formation was completed, 20 ml water was added into the mixture and the solution was neutralized, then the acetone was evaporated in vacuum. The aqueous concentrate was chromatographed on a column filled with 150 ml Diaion HP 20 resin (diameter of the column: 2.6 cm, height of the bed: 30 cm). As the eluting agent mixtures of acetone-deionized water were used, where the concentration of the acetone was increased in 5% steps. Pravastatin can be eluted from the column by a 15% acetone containing acetone-deionized water mixture. Fractions were analyzed by TLC. Fractions containing the product are combined and acetone was evaporated in vacuum. By lyophilization of the aqueous residue 1.3 g pravastatin was obtained. The chromatographically pure product was crystallized from a mixture of ethanol and ethyl acetate.
Melting point: 170-173° C. (decomp.)
[α] D 20 =+156°, (c=0.5, in water).
Ultraviolet absorption spectrum (20 μg/ml, in methanol): λ max =231, 237,245 nm
(log ε−4.263; 4.311; 4.136)
Infrared absorption spectrum (KBr): υOH 3415, υCH 2965, υC═O 1730, υCOO − 1575 cm −1 .
1 H-NMR spectrum (D 2 O, δ, ppm): 0.86, d, 3H (2-CH 3 ); 5.92, dd, J=10.0 and 5.4 Hz, 1H (3-H); 5.99, d, J=10.0 Hz, 1H (4-H); 5.52, br 1H (5-H); 4.24, m 1H (6-H); 5.34, br, 1H (8-H); 4.06, m, 1H (β-H), 3.65, m, 1H (δ-H); 1.05, d, 3H (2′-CH 3 ); 0.82, t, 3H (4′-H 3 ).
13 C-NMR spectrum (D 2 O, δ, ppm): 15.3, q (2-CH 3 ); 139.5, d (C-3); 129.5, d, (C-4); 138.1, s(C-4a), 127.7, d (C-5); 66.6, d (C-6); 70.1, d (C-8); 182.6 s (COO − ); 72.6. d (C-β); 73.0, d (C-δ); 182.0, s (C-1′) 18.8; q (2′-CH 3 ); 13.7, q (C-4′).
Positive FAB mass spectrum (characteristic ions):
[M+Na] + 469; [M+H] + 447.
Negative FAB mass spectrum (characteristic ions):
[M−H] − 445, [M−Na] − 423, m/z 101 [2-methyl-butyric acid-H] − .
Example 3
In a laboratory scale fermenter with 5 liters working volume, bioconversion culture medium MU/4 was prepared as described in Example 1, although it was loaded up to 4.5 liters, the composition of the culture medium was calculated to 5 liters. Then it was sterilized for 45 min at 121° C. and inoculated with 500 ml of the inoculum culture made according to Example 1. The fermentation was carried out at 25° C. by the application of a stirring rate of 300 rpm and an aeration rate of 50 liters/hour for 4 days. After 5 g compactin substrate feeding to the culture the bioconversion was carried out according to the Example 2.
After finishing the bioconversion, the 4.9 liters broth, which contained 660 μg/ml pravastatin, was filtered and the separated mycelium was washed by suspension in 2×1 liter deionized water. The pH of the combined 5.6 liters filtrate of the broth was adjusted by 20% sulfuric acid to 3.5-3.7, then the acidic filtrate was stirred with 2750 ml ethyl acetate for 30 min. Subsequently, the phases are separated. The aqueous phase was extracted again with 2×1375 ml ethyl acetate. 470 ml deionized water was added to the combined 4740 ml ethyl acetate extract, then the pH of the aqueous ethyl acetate mixture was adjusted to 7.5-8.0 by 1M sodium hydroxide. After 20 min stirring the phases were separated, then the ethyl acetate extract was extracted with 2×235 ml deionized water as described above. Then the combined weakly alkaline aqueous solution of 1080 ml volume was concentrated in vacuum to 280 ml volume. The concentrated aqueous solution was layered on a chromatographic column (ratio of height:diameter=6.5) filled with 280 ml Diaion HP-20 (Mitsubishi Co., Japan) non-ionic resin. The adsorption on the column was carried out with a flow rate of 250-300 ml/hour, then the column was washed with 840 ml deionized water. Subsequently, the column was eluted in the following order with 800 ml 5%, 1000 ml 10%, 500 ml 15% and 500 ml 20% acetone-containing water. In the course of the elution 50 ml fractions were collected, which were analyzed by the TLC method given in the Example 2. Fractions containing pravastatin as the main component were combined and the obtained solution was concentrated in vacuum to 260 ml volume. The concentrated aqueous solution was chromatographed on a column containing Diaion HP-20 resin in 260 ml volume. After the adsorption of pravastatin the column was washed with 790 ml deionized water, then eluted with aqueous acetone solutions in 260-260 ml portions gradually increasing the acetone content as follows: 2.5, 5.0, 7.5, 10.0, 12.5, 15.0 and 20.0%. In the course of the column chromatography 25 ml fractions were collected, and the pravastatin content of the fractions was analyzed as given before. Fractions containing pravastatin as the single component by TLC were combined and evaporated in vacuum. Subsequently, 0.3 g charcoal was added to the concentrated aqueous solution (about 30 ml) and pravastatin was clarified at room temperature for 30 min. Then the charcoal was removed by filtration from the solution and the filtrate was lyophilized. In this way 1.62 g pravastatin was obtained in lyophilized form.
Example 4
From the slant culture of the Mortierella maculata nov. spec. E-97 [NCAIM(P)F 001266] strain cultivated for 10-12 days, a spore suspension was prepared with 5 ml sterile 0.9% sodium chloride solution, and this suspension was used to inoculate 500 ml VHIG inoculum medium being sterilized in 3000 ml Erlenmeyer flask.
Composition of the medium VHIG:
glucose
30 g
meat extract
8 g
yeast extract
1 g
Tween-80 (polyoxyethylene (20) sorbitan monooleate)
0.5 g
in 1000 ml tap water.
Before the sterilization the pH of the medium was adjusted to 7.0 and the sterilization was carried out at 121° C. for 25 min. The culture was cultivated for 3 days on a rotary shaker (250 rpm, amplitude 2.5 cm), then the obtained inoculum culture was used to inoculate a laboratory scale fermenter containing bioconversion culture medium PK in 5 liters working volume.
Composition of the medium PK:
glucose
40 g
peptone
5 g
soybean meal
20 g
K 2 HPO 4
2 g
KH 2 PO 4
1 g
NaNO 3
2 g
KCl
0.5 g
in 1000 ml tap water.
Before the sterilization the pH of the medium is adjusted to 7.0. After the inoculation, cultivation, the substrate feeding and bioconversion were carried out according to Example 2, then the pravastatin was isolated from the broth in which its concentration was 650 μg/ml at the end of the fermentation.
Finishing the fermentation, the pH of the 4.9 liters broth containing 650 μg/ml pravastatin was adjusted under continuous stirring with 2M sodium hydroxide to 9.5-10.0, then after one hour stirring the pH is adjusted to 3.5-3.7 with 20% sulfuric acid. Subsequently, the acidic solution was extracted with 2.45 liters ethyl acetate. The phases are separated, and with centrifugation a clear extract was prepared from the emulsified organic phase. The broth was extracted again with 2×1.22 liters ethyl acetate by the method given above. The ethyl acetate extracts were combined and 0.4 liters deionized water were added, then the pH of the mixture was adjusted to 8.0-8.5 with 1 M sodium hydroxide. Phases were separated, and the ethyl acetate phase was extracted with 2×0.2 liters deionized water of pH 8.0-8.5 as given above. The pH of the combined pravastatin containing weakly alkaline aqueous solution was adjusted under stirring with a 20% sulfuric acid solution to 3.5-3.7. The acidic solution obtained was extracted with 4×0.2 liters ethyl acetate. The combined ethyl acetate extracts are washed with 2×0.2 liters deionized water, then 150 mole % dibenzylamine —calculated for the pravastatin content measured by HPLC —was added into the ethyl acetate solution. The ethyl acetate solution was concentrated in vacuum to 0.2 liters volume. Further 20 mole % dibenzylamine was added to the concentrate obtained, and the precipitated solution was kept overnight at 0-5° C. The precipitated pravastatin dibenzylamine salt was filtered, then the precipitate was washed on the filter with cold ethyl acetate and then two times with n-hexane, and finally it is dried in vacuum at 40-50° C. The crude product obtained (3.9 g) was dissolved in 100 ml methanol at room temperature, then the solution was clarified by 0.45 g charcoal. Thereafter the methyl alcoholic filtrate is concentrated in vacuum. The evaporated residue was dissolved in 120 ml acetone at an external temperature of 62-66° C., then the solution was cooled to room temperature. Subsequently, the recrystallization was continued overnight at 0-5° C. Precipitated crystals were filtered, then the crystals were washed on the filter two times with cold acetone and two times with n-hexane. The recrystallized pravastatin dibenzylamine salt was suspended in the mixture of 160 ml isobutyl acetate and 80 ml deionized water. Subsequently, sodium hydroxide was added in an equivalent amount into the suspension under stirring. After the disappearance of the suspension the phases were separated and the pravastatin containing aqueous solution was washed with 2×30 ml isobutyl acetate. The aqueous solution obtained was clarified with charcoal. Then the aqueous filtrate was concentrated to about 20 ml volume. The aqueous solution obtained was loaded on a chromatographic column (height:diameter=22) filled with 0.4 liters Sephadex LH-20 gel (supplier: Pharmacia, Sweden). In the course of the chromatography deionized water was used as the eluent, and 20 ml fractions were collected. Fractions were analyzed by TLC, then those containing pravastatin also by HPLC using the methods described above. Fractions containing pure pravastatin were combined and lyophilized. In this way 1.75 g pravastatin was obtained, the purity of which is higher than 99.5% by HPLC.
Example 5
A spore suspension was prepared from the slant culture of the Mortierella maculata n. spec. E-97 [NCAIM(P)F 001266] strain cultivated for 10-12 days with 5 ml sterile 0.9% sodium chloride solution, and then 500 ml inoculum medium was inoculated with it as described in Example 4. In a laboratory scale fermenter with 5 liters working volume bioconversion culture medium PC/4 is sterilized for 45 min at 121° C. and then inoculated with the seed culture.
Composition of the medium PC/4:
malt extract
5.0%
soybean meal
1.0%
peptone
1.0%
corn steep liquor
1.0%
MgSO 4 × 7 H 2 O
0.1%
in 1000 ml tap water.
Before the sterilization the pH of the medium is adjusted to 7.0. After the inoculation, the cultivation and substrate feeding were carried out according to the Example 2, and then 5.1 liters broth with a concentration of 610 μg/ml pravastatin was obtained.
From the broth 3.7 g pravastatin dibenzylamine salt crude product was produced by the method given in Example 4, from which after recrystallization 2.9 g pravastatin dibenzylamine salt was obtained. The recrystallized pravastatin dibenzylamine salt was suspended in 45 ml ethanol, then under stirring 110 mole % sodium hydroxide was added by the feeding of 1M ethanolic sodium hydroxide solution. Stirring of the solution is continued for half an hour, then 0.3 g charcoal was added into it and stirred for another half an hour. The solution was filtered, and the filtrate was concentrated to 15 ml. Then 60 ml acetone was added to the concentrate at 56-60° C. The solution obtained was cooled to room temperature, then kept overnight at +5° C. Subsequently, the precipitate was filtered, then washed with 2×20 ml acetone, 2×20 ml ethyl acetate and 2×20 ml n-hexane, and finally dried in vacuum. The resulting 1.7 g crude pravastatin was dissolved in ethanol, then clarified with charcoal and crystallized from an ethanol-ethyl acetate mixture. In this way 1.54 g pravastatin was obtained that was identical with the product of Example 2.
Example 6
As described in Example 4, from the slant culture of the Mortierella maculata n. spec. E-97 [NCAIM(P)F 001266] strain cultivated for 7-10 days, a 500 ml inoculum medium MI sterilized in a 3000 ml Erlenmeyer flask was inoculated and incubated at 28° C. for 3 days on a rotary shaker.
Composition of the medium MI:
glucose
40 g
casein
5 g
KCl
0.5 g
NaNO 3
3 g
KH 2 PO 4
2 g
MgSO 4 × 7H 2 O
0.5 g
FeSO 4 × 7H 2 O
0.01 g
in 1000 ml tap water.
Before the sterilization the pH of the medium is adjusted to 6.0 and the sterilization is carried out at 121° C. for 35 min. The seed culture obtained is inoculated into 5 liters bioconversion medium P12 sterilized in a fermenter.
Composition of the medium P12:
glucose
10 g
malt extract
50 g
yeast extract
5 g
corn steep liquor
5 g
MgSO 4 × 7H 2 O
1 g
Tween-80
0.5 g
in 1000 ml tap water.
Before the sterilization the pH of the medium is adjusted to 7.0, then the sterilization was carried out at 121° C. for 45 min. The fermentation, substrate feeding and bioconversion were carried out according to the Example 2. After finishing the bioconversion the pravastatin formed in the concentration of 620 μg/ml was isolated as follows:
The pH of 5.15 liters broth containing 620 μg/ml pravastatin was adjusted with 2M sodium hydroxide to 9.5 value then stirred at room temperature for 1 hour. The broth was filtered and the mycelium was washed with suspension in 1×2 liters and then 1×0.5 liters water. Filtrates are combined and the pH of the aqueous solution was adjusted with 20% sulfuric acid to 3.7 value and extracted with 2.5 liters then with 1.5 liters ethyl acetate. The ethyl acetate extracts were combined, washed with 2×0.5 liters water and 1.95 g dicyclohexylamine was added. The ethyl acetate extract was concentrated at 40° C. to 200 ml under reduced pressure, and 0.195 g dicyclohexylamine was added again into the concentrate, which was then stirred at 15° C. for 6 hours. The precipitated crystalline material was filtered, washed with 20 ml and with 15 ml ethyl acetate and dried at 40° C. In this way 3.51 g crude product was obtained. After the recrystallization of the crude product in an acetone-ethanol mixture, 3.05 g of pravastatin dicyclohexylamine salt was obtained (melting point: 162-168° C.), which was converted to pravastatin according to the Example 5.
Example 7
The fermentation, substrate feeding and bioconversion were carried out with the Mortierella maculata n. spec. E-97 [NCAIM(P)F 001266] strain as described in Example 2. Pravastatin obtained as a result of the bioconversion is isolated from the broth as follows.
5 liters culture broth containing in concentration 650 μg/ml pravastatin was filtered on a filter cloth. The mycelium of the mold was stirred in 2 liters 0.1M sodium hydroxide solution for an hour, then filtered. The two filtrates were combined and the pH was adjusted with 15% sulfuric acid to 3.5-4.0. Subsequently, the solution was extracted with 2×1.8 liters ethyl acetate. The combined ethyl acetate phases were washed with 800 ml water. Then 400 ml deionized water was added and the pH of the mixture is adjusted by 1M sodium hydroxide to a 8.0-8.5 value. The mixture was stirred for 15 minutes, then the phases were separated. 300 ml water was added to the ethyl acetate phase and the pH are adjusted to 8.0-8.5. After stirring for 15 minutes the phases were separated. 300 ml water was added again to the ethyl acetate phase and the pH was adjusted to 8.0-9.5. Then the mixture was stirred for 15 min. The two phases were separated again. All aqueous phases were combined and the pH are adjusted with 15% sulfuric acid to 3.5-4.0, then extracted with 3×300 ml ethyl acetate. The combined ethyl acetate extracts were washed with 150 ml water, dried with anhydrous sodium sulfate, and filtered. Then 150 mole % dioctylamine—calculated for the pravastatin content-was added to the ethyl acetate extract. The ethyl acetate was evaporated to about 1/10 volume and acetone was added until precipitation. The mixture was kept at +5° C. overnight. The precipitate was filtered on a G-4 filter, washed with 20 ml acetone and then with 20 ml n-hexane and dried in vacuum at room temperature. The 3.3 g crude pravastatin dioctylamine salt obtained was recrystallized from 20 ml acetone resulting in 2.7 g pure pravastatin dioctylamine salt. Melting point: 143-146° C. The pravastatin dioctylamine salt was converted to pravastatin with the method given in Example 5.
Example 8
By the development of the hydroxylation ability of Mortierella maculata n. spec. E-97 strain isolated from natural habitat, which is able to 6β-hydroxylate compactin, in the mutation-selection and enzyme induction experiments discussed in detail below, Mortierella maculata n. sp. E-97/15/13 [NCAIM(P)F 001267] mutant strain was produced.
Mortierella maculata n. sp. E-97 [NCAIM(P)F 001266] strain isolated by us was cultivated on MS slant agar medium at 28° C. for 7 days.
Composition of agar medium MS:
glucose
4 g
malt extract
10 g
yeast extract
4 g
agar
20 g
in 1000 ml distilled water.
Spores were washed off from the slant cultures by 5 ml 0.9% sodium chloride solution, then after transferring the spore suspension into a sterile Petri dish it was irradiated by ultraviolet light for 1 minute. Subsequently, N-methyl-N′-nitro-N-nitrosoguanidine was added to the spore suspension in the final concentration of 2000 μg/ml. Then the suspension was transferred into a 100 ml Erlenmeyer flask and it was shaken at 28° C. with a rate of 150 rpm for 20 min. Subsequently, the spores were sedimented by centrifugation with a rate of 4000 rpm for 10 min, then suspended in sterile 0.9% sodium chloride solution. The suspension was spread on an agar plate MU-VB containing 10 μg/ml benomyl and 1% defibrillated blood.
Composition of agar medium MU-VB:
glucose
40
g
asparagine
2
g
peptone
2.5
g
potassium dihydrogen phosphate
0.5
g
agar
20
g
in 990 ml distilled water; after sterilization the medium was completed with 10 ml bovine blood and 10 mg benomyl.
The agar plates were incubated at 28° C. for 7 days, then the grown colonies were transferred by random selection into test tubes containing agar medium PS.
Composition of agar medium PS:
glucose
40 g
mycological peptone
10 g
agar
15 g
in 1000 ml distilled water.
Before sterilization the pH of the medium is adjusted to 5.6-5.7 value. The sterilization is carried out at 121° C. for 20 min.
Slant cultures were incubated at 28° C. for 12 days, and their pravastatin productivity was tested in shaken flask experiments as described in Example 1. Mortierella maculata n. sp. E-97/15/13 mutant strain was selected by this method, which yielded pravastatin exceeding 60% conversion rate from the applied compactin acid sodium salt substrate being in the concentration of 1000 μg/ml.
The hydroxylase enzyme of Mortierella maculata n. sp. E-97/15/13 strain was induced by the cultivation on MU-VB agar medium containing 100 μg/ml 8-de-(2-methyl-butyryl) compactin and/or compactin. After random selection of the grown colonies they were transferred into inducer containing MU-VB slants. Pravastatin productivity of the grown slant cultures was examined by the method written in the Example 1 with the difference that the compactin substrate feeding in the quantity of 500 μg/ml was carried out from the 4th day of the fermentation for further 11 days and the compactin sodium substrate was added gradually during the twelve days converted completely to pravastatin. By the end of the bioconversion carried out in 50 shake flask cultures from 30 g compactin sodium substrate the formation of 18.5 g pravastatin was measured by HPLC. Recovery of the pravastatin from the combined fermentation broths was carried out according to the following method.
After finishing the fermentation the pH of 5.5 liters broth with a pravastatin concentration of 3360 μg/ml was adjusted with 20% sulfuric acid solution to 3.5-3.7. Subsequently, the acidic solution was extracted by 2.75 liters ethyl acetate. Phases were separated, and a clear extract was prepared by centrifugation from the emulsified organic phase. Broth was extracted two more times with 1.37 liters ethyl acetate as previously described. The combined ethyl acetate extracts were washed with 2×1.15 liters deionized water, then 150 mole % dibenzylamine—calculated for the pravastatin content measured by HPLC—was added to the ethyl acetate solution. The ethyl acetate solution was concentrated in vacuum to about 0.23 liters volume. Further 20 mole % dibenzylamine was added to the concentrate and the precipitate solution was kept overnight at 0-5° C. Precipitated pravastatin acid dibenzylamine salt was filtered, then the precipitate was washed by suspending it in cooled ethyl acetate and then two times in n-hexane, finally dried at 40-50° C. in vacuum. The crude product obtained (22.4 g) was dissolved in 0.67 liters acetone at 62-66° C. temperature, and the solution was clarified with 2.2 g charcoal. After the clarification the acetone filtrate was concentrated in vacuum to 0.56 liters volume. Crystals precipitated from the concentrate were dissolved again at the above temperature, then the solution was cooled to room temperature. Subsequently, the recrystallization was continued overnight at 0-5° C. Precipitated crystals were filtered, and washed by suspension two times in cooled acetone and two times in n-hexane. Recrystallized pravastatin acid dibenzylamine salt was dried in vacuum at 40-50° C. Pravastatin acid dibenzylamine salt obtained (14.8 g) was dissolved at 40-44° C. in 740 ml ethyl acetate-ethanol (9:1) mixture, then 110 mole % sodium hydroxide was added to the solution in form of a 1M ethanolic solution. Stirring of the obtained precipitated solution was continued for half an hour at room temperature, then a complete precipitation was achieved as a result of the application or ice cooling for 1-1.5 hours. Subsequently, the precipitate was filtered and washed with 2×150 ml cooled ethyl acetate and 2×150 ml n-hexane, finally dried in vacuum at 40-50° C. The pravastatin obtained was dissolved in ethanol, clarified by 1.0 g charcoal, then crystallized from ethanol-ethyl acetate mixture. This way 9.4 g pravastatin was obtained, with physical constants corresponding to the data given in Example 2.
Although certain presently preferred embodiments of the invention have been described herein, it will be apparent to those skilled in the art to which the invention pertains that variations and modifications of the described embodiments may be made without departing from the spirit and scope of the invention. Accordingly, it is intended that the invention be limited only to the extent required by the appended claims and the applicable rules of law.
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The present invention relates to a new microbial process for the preparation of the compound formula (I):
from a compound of general formula (II):
wherein R stands for an alkali metal or ammonium ion, by the submerged cultivation of a mold strain able to 6β-hydroxylate a compound of the Formula (II) in aerobic fermentation and by the separation and purification of the product of Formula (I) formed in the course of the bioconversion. The process comprises cultivating a strain of Mortierella maculata filamentous mold species that is able to 6β-hydroxylate a compound of the general Formula (II), on a nutrient medium containing assimilable carbon and nitrogen sources and mineral salts and separating the product formed from the fermentation broth, then isolating the compound of formula (I) and purifying the same. Novel strains of Mortierella maculata are also disclosed.
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SUMMARY OF THE INVENTION
The invention relates to two-way, or roll-over, plows and more particularly to an improved multiple bottom, two-way plow with lift assist.
The term "trash" is used by farmers to describe uncleared plant material, such as corn stalks and the like, left over in a field after crop cultivation and harvest. Plowing such a field to prepare a subsequent seedbed can result in the plow becoming plugged with soil and debris between adjacent plow bottoms. Best results are obtained when the space between plow bottoms for the entrance of soil and trash is great enough to provide the necessary clearance to avoid plugging of the plow. In the case of multiple bottom plows of the two-way or roll-over type, the greater spacing required between adjacent plow bottoms for proper trash clearance introduces severe mechanical problems in the design and manufacture of the plows because the extra spacing of the plow bottoms significantly increases the size and weight of the plow and, especially, the roll-over portions of the plows.
It is an object of the present invention to provide a two-way, or roll-over, plow with adequate trash clearance between plow bottoms in which said mechanical problems have been overcome.
Briefly, and in general, the present invention comprises a two-way, multiple bottom plow having a lift assist mechanism acting in conjunction with a standard three-point tractor hitch for lowering and raising the plow to and from its plowing position. Means are provided for automatically pivoting the roll-over portion of the plow through an arc of rotation of approximately 180° from a substantially horizontally disposed first plowing position to a similar, but opposite, second plowing position. Ascension of the roll-over portion of the plow during the first half of its rotation is effected by a fluid pressure cylinder under the control of a decelerating valve which successively decreases the flow of fluid to the cylinder as the roll-over portion of the plow approaches a vertical position and which completely shuts off the flow of pressure fluid to the cylinder once the roll-over portion has passed beyond the vertical. Descent of the roll-over portion of the plow then proceeds under the force of the weight of plow and against the resistance of the pressure fluid in the cylinder, which can bleed from the cylinder only through a restricted orifice. Additionally, the top hitch connection between the plow and the tractor is made through a spring biased pivotable linkage so that the top point of connection between plow and tractor can "float", that is, move relative to the plow.
IN THE DRAWINGS
FIG. 1 is a perspective view of a two-way, multiple bottom plow constructed in accordance with the teachings of the present invention;
FIG. 2 is a detailed view, partly in section, taken along the line 2--2 in FIG. 1;
FIG. 3 is a top view of the plow in operation;
FIG. 4 is a side view of the plow in its plowing position with the non-plowing position of the plow indicated in phantom outline;
FIG. 5 is a detailed view, partly in section, taken along the line 5--5 in FIG. 4;
FIG. 6 is a detailed view, partly in section, taken along the line 6--6 in FIG. 5;
FIG. 7 is a detailed view, partly in section, taken along the line 7--7 in FIG. 5;
FIG. 8 is a schematic drawing illustrating the hydraulic system of the plow and tractor with the plow in the plowing position;
FIG. 8A illustrates a variation in the system shown in FIG. 8;
FIG. 9 is a similar schematic drawing of the hydraulic system with the plow in its retracted, or non-plowing position and with the roll-over portion of the plow just past a vertical position;
FIG. 10 is a top view of another embodiment of the invention;
FIG. 11 is a side view of the embodiment of FIG. 10 showing the plow in plowing position; and
FIG. 12 is a detailed view, partly in section, taken along the line 12--12 in FIG. 11.
DETAILED DESCRIPTION OF THE INVENTION
Referring first to FIG. 1 there is shown a multiple bottom two-way plow 10 constructed in accordance with the teachings of the invention. The plow 10 comprises a plow chassis or frame 12, a plow supporting bar 14 to which the multiple plow bottoms 16, 16 are attached and which is diagonally disposed relative to the frame, a reversing bar 18 pivotably mounted on the frame for rotating the plow supporting arm from a first, substantially horizontally disposed plowing position to a second similar, but opposite, plowing position, a transverse hitch arm 20, a gauge wheel 80, and a lift assist mechanism 24 for aiding in lowering and raising the plow to and from its plowing position. As shown in the drawings, the frame 12, plow supporting bar 14, reversing arm 18 and hitch arm 20 are made of structurally strong members capable of sustaining large forces and stresses. In preferred form, the structural members are made in the form of box beams. The hitch arm 20 is welded to the plow frame 12 and the outer end of the reversing arm 18 is welded to the plow supporting bar 14. A stiffening member 26 is welded to both the plow supporting bar 14 and the reversing arm 18 and serves to insure the rigidity of the rollover portion of the plow. At its rearward end 28 the plow frame 12 carries a journal bearing (not shown) which receives a short journal shaft 30 fixed to the plow supporting bar 14. A similar journal shaft 32 is fixed to the reversing arm 18 adjacent its free end 34. The shaft 32 is journalled in a suitable bearing (also not shown) provided in a triangular shaped base member 36 welded to the top of the hitch arm 20. Both journal shafts are mounted on the same horizontal axis.
The hitch arm 20 is disposed transversely of the frame 12 and is also preferably constructed in the form of a box beam. At its opposite ends, the hitch arm 20 carries two pairs of generally triangular mounting or hitching brackets 38, 38. The brackets in each pair are disposed in close parallel relation to each other and depend below the hitch arm. Hitching pins 40, 40 are horizontally mounted at the lower ends of the brackets 38, 38 for connection to the lower arms of a standard three-point tractor hitch (shown in phantom outline, FIG. 1). Midway between its ends, the hitch arm 20 is provided with another pair of mounting brackets 42, 42. The brackets serve as a mount for a pivotable, spring-loaded hitching bar 44 for the top hitch of a standard three-point tractor hitch. The hitching bar 44 comprises a pair of parallel bars 46, 46 joined at the top and bottom. The bars are pivotably mounted on a horizontal pin 48 in the brackets 42, 42. At their upper ends, the bars 46, 46 carry two hitching pins 50, 50, either of which may serve as the upper connection for the three-point tractor hitch. At their lower ends, the bars 46, 46 are fixed by another horizontal pin 52 to a shaft 54 on which is mounted a coil spring 56. The spring 56 is confined between a retainer 58 on the shaft 54 and a bracket 60 depending from the underside of the plow chassis or frame 12. A collar 62 is pinned to the back end (left end as viewed in FIG. 6) of the shaft 54. The collar 62 permits the spring shaft 54 to move rearwardly of the plow frame but limits movement of the shaft forwardly upon abutment with the bracket. Tension of the spring 56 is preset according to the anticipated load forces to be encountered in the plowing operation. By reason of the described arrangement the connection between the plow and tractor at this upper hitch point "floats" to accommodate sudden movement of the plow relative to the tractor. Accordingly, should the gauge wheel of the plow drop into a hole or engage a large rock, the extreme forces which would otherwise be placed upon the upper tractor hitch are, in large part, absorbed in a compression of the spring 56.
The lift assist for the plow is located adjacent the rearward end 64 of the plow frame 12. As is best seen by reference to FIG. 4, the rearward portion 64 of the plow frame is elevated above the forward position 66 of the plow by a transition section 68. Parallel mounting brackets 70, 70 are welded to the underside of the frame and at their ends carry a horizontal pin 72 on which is pivotally mounted an L-shaped arm 74. The arm 74, in turn, is fixedly joined to a similarly shaped leg 76 which rides on an axle 78 between a pair of gauge wheels 80, 80. An hydraulic cylinder 82 and piston are mounted between the arm and the plow frame. The free end of the piston rod 84 is pivotally secured in the arm 74 adjacent the mounting brackets 70, 70 while the opposite end of the cylinder 82 is pivotally mounted on a pin 86 positioned in a pair of mounting brackets 88, 88 on the underside of the plow frame 12. Lowering of the plow frame is limited by an adjustable mechanical stop 90 located on the frame just forward of the mounting brackets 88, 88. The stop 90 comprises a pin 92 having a lower end 94 which may be selectively positioned below the frame for abutting engagement with the free end 96 of the arm 74.
Each plow bottom 16 is secured to a mounting arm 98 that is removably attached to an L-shaped bracket 100 welded to the plow supporting bar 14. The plow bottoms 16, 16 are arranged in oppositely disposed sets except that the points of the bottoms face in the same direction so that each set of bottoms turn the plowed furrows in a direction opposite to the other set. Thus, when alternate sets of plow bottoms are employed, plowing can proceed in adjacent traverses by the tractor and plow with all furrows being turned in the same direction. This permits the plow to be used more efficiently and results in a seedbed that is more level and better suited to irrigation.
The roll-over portion of the plow, that is, the plow supporting bar 14, the reversing arm 18, the stiffener 26 and the opposite set of plow bottoms 16, 16 are mounted for pivotable movement on the journal shafts 30, 32. Pivoting of these members is effected by an hydraulic cylinder 102 and piston. One end of the cylinder 102 is attached to a pin 104 pivotably mounted to the top of the base 36. The free end of the piston rod 106 is formed in the shape of a T and is confined in a pair of identical C-shaped slots 108, 108 formed in opposite walls 110, 110 of a mounting bracket 112 welded to the front surface of the reversing arm 18. As best seen in FIG. 5, each of the slots is formed with two circular openings 114, 114 that are joined by a straight section 116 which is offset from the center line of the circular openings 114, 114. Each circular opening is offset from the centerline of the roll-over portion of the plow and, hence, from the center of gravity for the roll-over portion. By pumping hydraulic fluid into the working end of the cylinder 102, the end of the piston rod 106 is moved tightly against the lower opening 114 and the vertical force component, acting through the rod on the slot, serves to pivot the reversing arm 18, the plow supporting bar 14, and opposite set of plow bottoms 16, 16 through an arc of rotation of substantially 180° to the opposite side of the tractor.
The hydraulic system for effecting the roll-over, or reversal, of the plow bottoms and plow supporting arm is shown schematically in FIG. 9. Operation of the system is initiated by the operator in the tractor cab through actuation of a detent valve 116. The detent valve 116 is moved to its open position and is maintained in said open position by a spring detent (not shown). The detent will hold the valve open until released by back pressure in the system. Adjustment of the spring detent enables the valve to be released upon realization of a predetermined amount of back pressure. When the detent valve 116 is placed in its operating position, pressure fluid is valved to the rod side of the piston within the roll-over cylinder 102 through conduit 118. The force of the pressure fluid on the piston lifts the reversing, or roll-over, arm 18 and consequently the plow supporting bar 14 and plow bottoms 16, 16 and starts the roll-over operation. As the plow supporting bar 14 pivots toward a vertical position, a valveactuating plate 120 secured to the bar contacts the roller cam 122 of a normally-open decelerating valve 124 mounted on the rearward portion of plow frame 12. As rotation of the plow supporting bar continues the plate 120 continues to depress the cam 122 farther inwardly of the valve thereby decreasing the flow of pressure fluid to the cylinder 102. Decreasing the flow of pressure fluid to the cylinder compensates for the fact that as the plow supporting bar 14 pivots during the roll-over operation the amount of pivotal movement of the bar increases relative to the amount of piston travel in the roll-over cylinder. Decreasing the flow of pressure fluid to the cylinder decreases the piston travel in the cylinder and insures a substantially uniform angular travel of the plow supporting bar as the bar approaches a vertical position.
By the time the roll-over portion of the plow has passed its vertical position (shown in FIG. 9), the decelerating valve 124 closes. Closing of the valve 124 produces a back pressure in the system great enough to release the detent on the valve 116 and to allow the valve to automatically return to its normally closed position. Because the circular recesses 114, 114 in the C-slots 108 are offset from the center line of the reversing arm 18, the roll-over portion of the plow will always be past top dead center when the valve 124 shuts off. With the roll-over portion of the plow past center, the remaining portion of the roll-over operation is effected simply by the weight of the plow acting against the piston in the cylinder 102. Further angular travel of the rollover portion of the plow now reverses the direction of travel of the piston in the cylinder. Fluid is forced out of the cylinder 102 through a restricted orifice 126 in a by-pass line 128 to the opposite side of the piston. Restricting the flow of pressure fluid through the orifice 126 controls the downward movement of the plow through the second half of its travel and prevents the plow from slamming against the plow frame.
The roll-over operation is automatic and independent of operator control once the detent valve 116 in the tractor cab is placed in its open position to initiate the operation. Accordingly, the operator is free to look ahead and concentrate on turning the tractor and plow around during the roll-over sequence. By the time the operator has the tractor and plow reversed, the roll-over of the plow is completed and the plowing operation in the reverse direction can be started immediately. During the plowing operation when the operator is free to do so, the detent valve 116 is quickly reversed for a brief moment and then returned to its closed position. While the valve is thus briefly open, pressure fluid is valved to the head side of the piston through the line 130 and the piston rod 106 is moved slightly outwardly. This slight outward movement permits the end of the piston rod 106 to drop downwardly into the opposite circular recess 114 in the C-slot 108 where it is in proper position to lift the reversing arm 18 upon the start of the next roll-over operation. A check valve 132 is placed in the line 118 to prevent the "powering down" of the roll-over portion of the plow in the event the operator mistakenly moves the detent valve to the reverse position while the plow supporting arm is in its second half, or downwardly moving, stage. Automatic roll-over operation is achieved by the deceleration valve 124. If desired, the valve 124 can be omitted. In such a case the operator would manually close the valve 116 once the roll-over portion had passed beyond the vertical.
As the roll-over portion of the plow completes its pivotal movement from one side of the tractor to the other, the reversing arm 18 comes to rest upon an adjustable stop member 111 located on a laterally extending pad 113 welded to the side of the bracket 38. Immediately adjacent to the stop member 111, the pad 113 carries an upwardly extending bar 115. The bar 115 is tall enough to extend inwardly of an opening 117 formed in the stiffener 26 and the top of the bar 115 is formed with a beveled face 119 that serves to engage and guide a roller 121 mounted in the opening 117. The longitudinal depth of the opening 117 is such that the bar 115 and roller 121 are snugly accomodated therein. Engagement of the bar and roller is in substantial alignment with a lower hitch connection with the tractor and this cooperative arrangement insures that the pulling force of the tractor is always transmitted to the plow along the longitudinal axis of one or the other of the lower hitch arms 138. An identical arrangement is provided at each side of the plow.
The hydraulic system for lifting and lowering the plow is shown schematically in FIG. 8. Lifting of the plow is effected by two single acting hydraulic cylinders 82, 134. One cylinder 134, or a pair of cylinders in tandem, are located at the tractor hitch 136 and serve to raise the lower arms 138, 138 of the three-point hitch. The second cylinder is the lift assist cylinder 82 positioned between the plow frame 12 and the arm 74. When the operator wants to raise the plow from its lowered, plowing position, he opens a throttling valve 140 in the tractor cab. Opening of the valve 140 introduces pressure fluid to the cylinders 82, 134 through the line 142. Pressure fluid in the cylinders 82, 134 moves the piston of the tractor hitch inwardly thereby causing the hitch arms 138, 138 to pivot upwardly relative to the tractor 143. At the same time, the piston in the lift assist cylinder 82 moves outwardly causing the arm 74 to rotate clockwise about the pivot 72 so as to raise the rearward end of the plow frame 12. Lowering of the plow is accomplished by the weight of the plow. When the operator wishes to lower the plow, the throttling valve 140 in the cab is closed thus communicating the cylinders 82,134 with the fluid reservoir 141. The weight of the plow then causes the pistons to reverse their travel and to lower the plow.
To protect the lift assist mechanism against damage in the event the gauge wheels 80, 80 fall into a deep hole, a lock valve 144 and auxiliary fluid tank 146 are provided on the flow frame 12. The valve 144 is communicated with the rod side of the piston in the lift assist cylinder 82 by the line 148. The valve 144 is normally closed and in the closed position prevents the exit of fluid from the rod side of the piston. Should the gauge wheels 80,80 fall into a large hole, the fluid trapped behind the piston prevents the leg 74 from pivoting clockwise about the pin 72 and prevents damage to the cylinder and piston which would otherwise occur if the pivoting were not restrained and if it were severe enough. When the main line 142 is under pressure, as when the plow is being raised, the valve 144 is open and fluid behind the piston can escape to the auxiliary tank 146.
In an alternative construction shown in FIG. 8A, the lock valve and tank are replaced by an accumulator 150 which is connected to the rod side of the piston in the cylinder 82. The accumulator 150 resists displacement of the fluid behind the piston and thus serves to prevent injury to the lift assist mechanism. Additionally, the accumulator creates a back pressure behind the piston that aids in restoring the mechanism to its proper positioning.
An alternate construction for the gauge wheel and lift assist mechanism is shown in FIGS. 10-12. In this form of the invention the gauge wheel 80 comprises a wide, single wheel rather than two parallel wheels of normal size. The greater width of the wheel provides more support for the plow in wet soil conditions. To accomodate the greater width of the wheel, the plow frame is constructed with two parallel side beams 152,152 that are joined at the front of the plow to the ends of the hitch arm 20. At the rearward end of the plow the side beams 152, 152 having converging sections 154, 154 which meet at the center line of the plow. The gauge wheel 80 is positioned between the side beams. The axle 78 for the wheel is mounted in the sides of a yoke 156 which straddles the wheel. The yoke 156 has an upper crossbar 158 that passes over the wheel and the crossbar is connected to the outer end 159 of an actuating arm 160 for the lift assist mechanism. At its opposite end 161 the actuating arm 160 is pivotally mounted on a pin 162 fixed in a pair of mounting brackets 164, 164 depending from the plow frame. The actuating arm 160 has a pair of brackets 166, 166 formed at the sides of the top surface and a pin 168 is positioned between the brackets. An hydraulic cylinder 170 is pivotably connected to the pin. The piston rod 169 for the cylinder is pivotably connected to another pin 172 located in a pair of brackets 174, 174 on the plow frame.
Operation of the lift assist is similar to the embodiment previously described. When pressure fluid is introduced to the cylinder 170 the piston rod is moved outwardly thereby raising the plow frame. Raising of the plow frame causes the yoke 156 to pivot clockwise relative to the wheel 80 (as viewed in FIG. 11). Lowering of the plow is achieved by introducing pressure fluid to the reservoir. Selectively adjustable stops 176, 176 are mounted on the side beams 152, 152 and engage lateral wings 178, 178 formed on the bottom edges of the sides of the yoke 156 to limit the depth of the plow bottoms in the soil.
Normally the wheel 80 is locked against turning during the plowing of each furrow. For this purpose the front end 180 of the yoke 156 has a crossbar 182 to which a laterally-extending pin 184 is attached. When the plow is lowered to its operating position (the desired plowing depth), the pin 184 fits within a slot 186 formed in a locking plate 188 positioned between the side beams 152, 152. The slot 186 terminates at its lower end in a larger divergent opening 190. As the plow is raised the yoke 156 pivots clockwise of the wheel 80 and the pin 184 moves downwardly out of the slot 186 into the opening 190. The wheel 80 is then free to turn as the tractor and plow turn around at the end of the furrow.
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An improved two-way, multiple bottom plow is described. The plow is provided with an hydraulically actuated lift assist mechanism which works in conjunction with the tractor hitch to lift the plow out of the plowing position. A hydraulic system is provided for automatically pivoting the roll-over portion of the plow from one side of the tractor to the opposite side. Ascension of the roll-over portion of the plow to a point past the vertical is effected by powered hydraulic roll-over cylinder which is then shut off. The roll-over portion of the plow then descends under its own weight against the resistance of trapped pressure fluid which can only bleed off through a restricted orifice. The top hitch between tractor and plow is a spring biased pivotable connection which can "float" relative to the plow.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of copending International Application No. PCT/DE99/01482, filed May 17, 1999, which designated the United States.
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a pyrolysis plant for refuse and a method for screening solid residues, through the use of which coarse solid fragments are separated from finer solid fragments.
In many industrial areas of use, it is necessary for solids which are contained, for example, in bulk material to be separated into a plurality of fractions. The fractions are, as a rule, subdivided according to different solid sizes, solid geometries or solid constitutions. Separation of solids is desirable whenever the different solid fractions are to be supplied for further treatment.
In the building industry, for example, building debris which occurs is separated from large and bulky debris constituents which are then sorted and reutilized. The separated finer building debris is disposed of, for example, at a dump provided for that purpose.
In the field of waste disposal, separation and sorting of the waste or of residues occurring during waste utilization are of ever-increasing importance with a view toward disposal which is as protective of the environment as possible. An essential factor therein is the separation of waste according to its size. Separation may be carried out before the waste is utilized. However, it may also be an essential method step in waste utilization itself.
Thermal methods are known for the elimination of waste, in which the waste is burned in refuse incineration plants or pyrolysed in pyrolysis plants, that is to say subjected to a temperature of about 400° C. to 700° C., with air being excluded. In both methods, it is expedient to separate the residue remaining after incineration or after pyrolysis, in order to either supply it for reutilization or dispose of it in a suitable way. The aim, in that case, is to keep the amount of residue to be ultimately stored at a dump as low as possible.
European Patent Application 0 302 310 A1, corresponding to U.S. Pat. No. 4,878,440, and a company publication entitled “Die Schwel-Brenn-Anlage, eine Verfahrensbeschreibung” [“The Low-Temperature Carbonization Incineration Plant, a Method Description”], published by Siemens AG, Berlin and Munich, 1996, disclose, as a pyrolysis plant, a so-called low-temperature carbonization incineration plant, in which essentially a two-stage method is carried out. In the first stage, the waste supplied is introduced into a low-temperature carbonization drum (pyrolysis reactor) and is carbonized there at low temperature (pyrolysed). During pyrolysis, low-temperature carbonization gas and pyrolysis residue occur in the low-temperature carbonization drum. The low-temperature carbonization gas is burned, together with combustible parts of the pyrolysis residue, in a high-temperature combustion chamber at temperatures of approximately 1200° C. The waste gases occurring at the same time are subsequently purified.
The pyrolysis residue also has non-combustible constituents in addition to the combustible parts. The non-combustible constituents are composed essentially of an inert fraction, such as glass, stones or ceramic, and of a metal fraction. The useful materials of the residue are sorted out and supplied for reutilization. It is necessary to have methods and components which ensure reliable and continuous operation for the sorting-out process.
In the case of screening devices, there is often the problem of screen surfaces becoming clogged. The screening device then breaks down, or at least it must be subjected to complicated and labor-intensive cleaning. The problem of the blockage of the screening device arises particularly when the solid to be separated has a highly inhomogeneous composition. Thus, for example, wires catch in perforated plates used as screen surfaces, so that the individual holes are first narrowed and, in time, become clogged.
The residue occurring during the pyrolysis is typically a highly inhomogeneous solid which has pronounced differences in terms of its material composition, its size and the geometry of its solid fragments. The residue contains not only stones, broken glass and larger metal fragments, but also elongate bars and entangled wires (wire pellets).
A device for discharging pyrolysis residue from a low-temperature carbonization drum is known, for example, from International Publication No. WO 97/26495, in order to provide for the separation of coarse pyrolysis residue. The discharge device includes a conveying device which has a separating bottom with a sawtooth-like profile as well as a downstream bar screen. The separating bottom is set in vibration, so that the fine constituents are separated from the coarse on the separating bottom. The fine constituents fall through the downstream bar screen, while the coarse constituents slide along on the latter. However, wire pellets may catch on the bars and lead to a blockage.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a pyrolysis plant for refuse and a method for screening solid residues, which overcome the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and in which continuous operation is ensured by simple measures, without blockages occurring.
With the foregoing and other objects in view there is provided, in accordance with the invention, a pyrolysis plant for refuse, comprising a screening device having an interior for receiving solid residues, a rod wound along a helical line and bounding the interior, and a longitudinal axis, the screening device rotatable about the longitudinal axis.
The decisive advantage of a screening device constructed in this way is to be seen in that wire pellets or other solids cannot remain adhering to the rod. Thus, due to the rotation of the screening device and because of the turn of the rod, the wire pellets are thereby pushed down in the conveying direction. Blockages are therefore effectively avoided.
In accordance with another feature of the invention, the rod is constructed as a spiral with a plurality of turns, in particular with about four to ten turns.
In a screening device of this kind, which may also be referred to as a “spiral screen”, the solids to be screened are introduced into the interior formed by the three-dimensional spiral. Fine solids having smaller dimensions than the distance between two turns of the spiral fall through the spiral, while coarse solids are conveyed further in the interior. The maximum size of the screened finer solid constituent can be set by a suitable choice of the distances between the turns. The rotational movement of the spiral ensures that the coarser solid fragments are transported reliably and continuously in the conveying direction from the start to the end of the spiral.
An essential advantage of the spiral is that waste fragments possibly jammed between two turns are raised as a result of the rotational movement and, in particular, fall down due to their dead weight at an upper reversal point. The simple and robust construction of the screening device as a spiral therefore automatically avoids permanent blockages and allows continuous operation.
In accordance with a further feature of the invention, a number of rods are provided and the rod starts thereof are disposed so as to be offset in terms of rotation. In this case, each rod runs along a helical line. Such a screen having a plurality of rods is also referred to as a multi-flight screen.
In accordance with an added or alternative feature of the invention, the angle of rotation of the rods is smaller than 360°. In particular, the angle of rotation is smaller than or approximately equal to 180°. The screening device may be constructed with a plurality of rods which do not execute a complete revolution, so that it can be made more robust, as compared with a spiral screen having a plurality of turns.
In accordance with an additional feature of the invention, there is provided a rod element fixed relative to the rod, both in the spiral screen and in the multi-flight screen. The rod element runs essentially parallel to the outer surface formed by the spiral or parallel to the outer surface formed by the multi-flight screen.
This rod element acts as follows as a stripping element: when a wire pellet catches on the rod, then, as a result of the rotational movement of the screen, this wire pellet is guided against the fixed rod element and is stripped off from the rod by the fixed rod element along the helical line. In order to achieve this, the direction of rotation of the rod is suitably coordinated with the direction of rotation of the screening device.
In accordance with yet another feature of the invention, in order to provide stripping which is as efficient as possible, the rod element is likewise wound along a helical line, specifically and in particular in opposition to the rod, so that, for example, the rod element forms an angle of preferably 90° with the rod.
In accordance with yet a further feature of the invention, the spiral is fastened in the spiral screen only at one of its two ends, so that the spiral axis is curved downwards in the direction of gravity towards its non-fastened end as a result of dead weight. Preferably, the spiral is held only at the spiral start, while the spiral end which is located in the conveying direction is constructed to be freely suspended.
As an alternative to a spiral fastened on one side, an already curved spiral may also be fastened on both sides. It is essential that the spiral be curved.
The decisive advantage of the curvature is to be seen in that the distances between the turns on the underside of the spiral are smaller than the distances on the top side of the spiral. Solids introduced into the spiral may, in principle, be jammed only between turns on the underside of the spiral, since the solids fall downwards due to their dead weight, as soon as they are raised. In other words: due to the spiral movement, a jammed solid fragment is raised upwards along with the spiral. At the same time, the distance between the turns widens, so that the solid fragment cannot remain jammed between the turns and necessarily falls down due to its dead weight. The screening device with a curved spiral is therefore to a great extent self-cleaning.
In accordance with yet an added feature of the invention, in order to make the curvature of the spiral possible, it is expedient for the spiral to have a flexible construction. At the same time, stresses acting on the spiral due to jammed solid fragments are thereby kept low.
In accordance with yet an additional feature of the invention, in order to provide a stable and simple construction, the rod forming the spiral is advantageously metallic and, in particular, a round iron bar or an iron or steel tube. Such a spiral is extremely robust and is also suitable, in particular, for the coarse separation of heavy and large solids. The spiral is made from plastic, for example, for instances of use in which only slight loads occur.
In accordance with again another feature of the invention, there is provided an aligning device for the alignment of elongate solid fragments in the conveying direction in the screening device. The aligning device is disposed upstream of the rod in the conveying direction and opens into the interior.
The alignment of elongate solid fragments ensures that they are introduced, essentially parallel to the longitudinal axis, into the interior. Elongate solid fragments are therefore likewise treated automatically as coarse solid fragments and conveyed further. They cannot fall through the spiral perpendicularly to the longitudinal axis. This ensures that the solid fragments falling through the screen formed by the rod or rods are only those which have their largest dimensions being smaller than the distance between two turns of the spiral or the distance between two rods.
In accordance with again a further feature of the invention, the aligning device is constructed as a drum rotatable about its longitudinal axis in order to ensure simple alignment of the elongate solid fragments. The solid fragments are automatically aligned in the direction of the drum axis by virtue of the rotational movement of the drum.
In accordance with again an added feature of the invention, there is provided a coil, that is to say a helically wound strip, placed on the inside of the drum. This coil prevents solids, introduced into one drum end, for example through a filler shaft, from running through the drum at too high a speed, so that the solids “fly” through the interior formed by the rod, without screening taking place. Preferably, the coil has a multi-flight construction for this purpose, that is to say a plurality of helical strips, which are disposed so as to be offset in terms of rotation. The coil is, in particular, disposed directly on the inlet side of the drum and has a relatively high side.
In accordance with again an additional feature of the invention, the coil is constructed in such a way that it forms a closed circle, as seen in a top view in the direction of the longitudinal axis of the drum.
This rules out the possibility of solids on the drum bottom being able to slide through, unobstructed, in a straight line from the drum entrance as far as the drum exit. A multi-flight coil with an angle of rotation smaller than 360° is preferred so as not to impede the solid flow unnecessarily. In this case, the desired overlap of the side is achieved and, at the same time, a relatively low pitch of the coil is made possible, so that it becomes possible for solids to be transported quickly within the drum.
In an alternative embodiment, the aligning device is constructed as a profiled vibrating bottom which is provided with longitudinal grooves running in the conveying direction and in which the elongate solid fragments are aligned in these longitudinal grooves due to the vibrations of the vibrating bottom.
In accordance with still another feature of the invention, the rod is fastened to the drum on the end surface of the drum located in the conveying direction and, in particular, is welded there. The rod is preferably fastened in such a way that the drum exit opens into the interior formed by the rod. Therefore, in order to provide a frictionless material discharge from the drum, the rod is fastened to the outer wall of the drum or is at least flush with the drum.
In this embodiment, the aligning device and the rod form a structural unit with a particularly simple construction which is robust and reliable.
In accordance with still a further feature of the invention, the screening device is connected to a discharge side of a low-temperature carbonization drum of a pyrolysis plant for the screening of pyrolysis residues obtained from the low-temperature carbonization drum.
In the pyrolysis plant, a first separation of the pyrolysis residue into a fine and a coarse residue fraction is preferably carried out through the use of the screening device. Reliable and continuous operation of the entire pyrolysis plant is ensured by virtue of the simple and particularly robust construction of the screening device.
It is particularly advantageous and expedient for the screening device to be fixedly connected directly to the low-temperature carbonization drum on the discharge side of the latter. Consequently, no other components, which may cause a fault, are interposed between the low-temperature carbonization drum and the screening device. The rod is, for example, fastened directly to a discharge pipe of the low-temperature carbonization drum and is disposed within a discharge device. This discharge device is preferably sealed off in a gas-tight manner relative to the outside atmosphere, in order to avoid the ingress of atmospheric oxygen which would lead to combustion of the combustible and hot pyrolysis residue.
In accordance with still an added feature of the invention, particularly for the purpose of the coarse screening of residue from a large-scale pyrolysis plant, the distance between two turns of the spiral or between two rods is advantageously about 100 mm to 300 mm and, in particular, about 180 mm.
In accordance with still an additional feature of the invention, the interior formed by the rod has a length of about 0.5 to 1.5 m. Its diameter amounts to about 1.5 m, and a screening device with a drum and a screen preferably has a total length of about 2 to 4 m. The length of the interior is expediently smaller than or equal to the diameter of the drum.
With the objects of the invention in view, there is also provided a method for screening solid residues from a pyrolysis plant for refuse, which comprises providing a screening device having a longitudinal axis, an interior and a rod wound along a helical line; introducing residues into the interior of the screening device rotating about the longitudinal axis; and conveying coarse residue constituents with the rod for separating the coarse residue constituents from pure residue constituents.
In accordance with a concomitant mode of the invention, there is provided a method which comprises initially aligning the residues in a conveying direction in an aligning device and subsequently screening the residues with the rod.
The advantages and particular embodiments explained with reference to the screening device also apply accordingly to the method.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a pyrolysis plant for refuse and a method for screening solid residues, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic, side-elevational view of a screening device, in which a drum as an aligning device is fixedly connected to a spiral;
FIG. 2 is a sectional view through a curved spiral, which is provided in order to explain an advantageous action of the screening device;
FIG. 3 is a side-elevational view of a low-temperature carbonization drum with a spiral fastened thereto; and
FIG. 4 is a side-elevational view of a screening device with a number of rods as a multi-flight screen.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the figures of the drawings in detail and first, particularly, to FIG. 1 thereof, there is seen a screening device 1 which includes an aligning device, specifically a drum 2 , that is rotatable about its longitudinal axis and which is inclined relative to the horizontal. A shaft-like feed device 6 for solids R is disposed on a left-hand end surface 4 of the drum 2 . These solids R are, for example, pyrolysis residue or building debris. A metal rod 8 which is wound along a helical line and which forms a spiral 10 with an interior 11 , is fastened to a right-hand end surface 7 of the drum 2 . The right-hand end surface 7 is located opposite the feed device 6 . The spiral 10 is fastened to the drum 2 , for example through the use of a suitable welded, screwed or clamping connection. The spiral 10 is approximately flush with the drum 2 , so that the diameter of the drum 2 and that of the spiral 10 are approximately equal. This makes it possible to use the entire right-hand end surface 7 as a drum exit for the solids R, and to construct the drum 2 , for example, as a simple metal tube. A common longitudinal axis 3 of the screening device 1 and of the drum 2 coincides essentially with a spiral axis 12 of the spiral 10 .
The drum 2 is mounted rotatably and can be set in rotation through a drive which is not illustrated in detail. The spiral 10 fastened to the drum 2 also rotates together with the drum 2 . According to FIG. 1, the spiral has five turns. The distance between two adjacent turns depends on the type of solids R. In the present case, it is preferably about 180 mm. The spirally wound rod 8 is formed of a robust material and, in particular, is metallic. It is, for example, a round iron bar or a steel tube. The spiral 10 is fastened on only one side, specifically to the drum 2 . Its spiral end facing away from the drum 2 is free of fastening devices and is not supported. The spiral 10 will therefore curve downwards towards its non-fastened end due to gravity. This is discussed in more detail further below with reference to FIG. 2 .
The solids R are introduced into the drum 2 through the feed device 6 and are transported in a conveying direction 14 towards the spiral 10 as a result of the inclination of the drum 2 and of the rotational movement. Fine solids F are separated in the spiral 10 , while coarse solids G are transported further by the spiral 10 .
An essential advantage of the screening device 1 having the spiral 10 is to be seen in that even solids R flowing sluggishly are transported in the conveying direction 14 in a simple way as a result of the rotational movement.
Due to the rotational movement of the drum 2 , elongate solid fragments 16 are at the same time aligned in the conveying direction 14 , so that they are guided, approximately parallel to the spiral axis 12 , into the interior 11 of the spiral 10 . This reliably avoids a situation in which the elongate solid fragments 16 pass into the spiral 10 perpendicularly to the spiral axis 12 and fall through the spiral 10 . Only the fine solids F can therefore fall through the spiral 10 , and they are collected in a first collecting container 18 and transported away, as required. The coarse solids G are led through the spiral 10 . At the end of the spiral 10 , the coarse solids G fall into a second collecting container 20 and are likewise transported away, as required. Conveying devices, such as transport belts or transport worms, may also be provided instead of the collecting containers 18 , 20 , in order to transport the solids F, G away continuously.
FIG. 2 shows a diagrammatic, sectional view through a curved spiral 10 . The essential functional principle of the curved spiral 10 is explained with reference to this figure. According to FIG. 2, the spiral axis 12 (and with it, the entire spiral 10 ) has a curvature. By virtue of the curvature, an upper distance o between two successive turns is greater than a lower distance u between two turns. A solid fragment R can only be jammed in the lower region of the spiral 10 , where the distance u between two turns is small. A jammed solid fragment P is conveyed upwards as a result of the rotational movement of the spiral 10 and, at the same time, the distance between the turns becomes greater, so that the solid fragment P is released and falls down.
The same applies analogously to wire pieces 24 or similar solid fragments which are hook-shaped and catch over the rod 8 with a hook opening. If the screen were to move in only one plane, such wire pieces 24 would, as a rule, lead to blockage. In the present case, during rotation, a wire piece 24 is guided upwards together with the spiral 10 . The hook opening is directed upwards, particularly at an upper reversal point of the spiral 10 , so that the wire piece 24 can fall down.
This advantageous mechanism of the spiral 10 is obtained, irrespective of whether or not the spiral 10 has a curvature.
According to FIG. 3, a low-temperature carbonization drum 26 of a pyrolysis plant is charged with waste A through a feed shaft 27 and a supply device 28 . The waste A is carbonized at about 450° C. in the low-temperature carbonization drum 26 . In this case, a low-temperature carbonization gas S and a solid or pyrolysis residue R are obtained. The low-temperature carbonization drum 26 is preferably heated through internal heating tubes which are not illustrated in detail. It is inclined relative to the horizontal and is mounted rotatably. A discharge tube 29 is disposed on that end surface of the low-temperature carbonization drum 26 which is located opposite the supply device 28 , and the spiral 10 is fastened at an end surface of the discharge tube 29 . The discharge tube 29 and the spiral 10 form the screening device 1 . The discharge tube 29 serves at the same time as an aligning device for elongate solid fragments. The fine solid constituents F are separated from the coarse solid constituents G through the use of the spiral 10 .
The discharge tube 29 together with the connected spiral 10 open out into a discharge device 30 which is sealed off in a gas-tight manner relative to the rotating low-temperature carbonization drum 26 through sliding-ring seals 32 . The supply device 28 is also sealed off in a gas-tight manner relative to the low-temperature carbonization drum 26 through sliding-ring seals 32 , in the same way as the discharge device 30 . This is done to avoid a situation in which atmospheric oxygen penetrates into the low-temperature carbonization drum 26 and impairs the pyrolysis process, which takes place largely free of oxygen in the low-temperature carbonization drum 26 . In addition to the pyrolysis residue R, the low-temperature carbonization gas S is present in the low-temperature carbonization drum 26 . The low-temperature carbonization gas S flows through the discharge tube 29 into the discharge device 30 and is diverted from there through a low-temperature carbonization gas extraction connection piece 34 .
In an alternative version, the spiral 10 disposed in the discharge device 30 may be followed by a tube 37 which is illustrated by broken lines in FIG. 3 and through which the coarse solids G are discharged from the discharge device 30 . In this case, the spiral 10 is disposed between the discharge tube 29 and the tube 37 .
The pyrolysis residue R is separated, immediately downstream of the low-temperature carbonization drum 26 , into fine solid constituents F and coarse solid constituents G through the use of the configuration of the spiral 10 on the discharge tube 29 of the drum 26 . There is therefore only a slight risk of blockage of components located downstream of the low-temperature carbonization drum 26 .
The screening device is suitable, in general, for direct connection to rotary tubes, such as, for example, rotating tubular kilns or low-temperature carbonization drums, in which the solids undergo treatment because they are to be separated.
The fine residue F which is separated through the use of the screening device 1 is preferably subjected to so-called air separation for further processing. In this case, the light, in particular carbon-containing solid constituents are separated from the heavy constituents. During such air separation, the solids are supplied to an air stream, so that the light solid constituents are entrained by the air stream. It has proved particularly expedient to have a zig-zag-shaped shaft, into which the air is supplied from below and the solids are supplied from above or laterally.
FIG. 4 illustrates an embodiment which is an alternative to the spiral 10 and in which a number of rods 8 are disposed at the end of the drum 2 , instead of the spiral 10 . In each case the rods 8 are wound along a helical line and may therefore be considered as a multi-flight coil. The individual rods 8 are disposed in such a way as to be offset in terms of rotation relative to one another, preferably at an angle of 30°, at the end of the drum 2 . Each individual rod 8 has an angle of rotation smaller than 360°, that is to say it does not execute a complete revolution. A particularly robust construction thereby becomes possible.
The decisive advantage of this multi-flight coil, and of the spiral 10 according to FIG. 1 as well, is the provision of one or more helically wound rods 8 . This is done so that, as a result of the rotational movement of the screening device 1 provided by a motor M, solid fragments which may possibly be caught are automatically transported further to the end of the screening device and are discarded there.
In order to assist this self-cleaning mechanism, provision is made for use of a rod element 35 which runs essentially parallel to an outer surface formed by the rods 8 . The rod element 35 may also be disposed in the embodiment having the spiral 10 . The rod element 35 ensures that a solid fragment caught on a rod 8 is drawn off from the latter in the conveying direction 14 by virtue of the relative movement between the rod 8 and rod element 35 . For this purpose, the direction of rotation of the screening device 1 and the direction of rotation of the rods 8 are coordinated with one another.
In order to increase the stripping action, the rod element 35 is likewise wound along a helical line and intersects the rods 8 preferably at an angle of 90°. The pitch of the rod element 35 preferably increases in the conveying direction 14 , in order to increase the stripping action. The action is improved even further if a plurality of rod elements 35 are provided. For example, they may be disposed below the rods 8 approximately in a semicircle.
Another advantage of the provision of the rod element 35 is to be seen in that elongate solid fragments 16 which are not aligned completely parallel to the longitudinal direction 3 in the drum 2 cannot fall through a gap between the rods 8 . Specifically, due to the rotational movement of the drum 2 , the elongate solid fragments 16 may also be raised, so that they strike the rods 8 at an acute angle at the outlet of the drum 2 .
Furthermore, it may be gathered from FIG. 4 that a multiple or multi-flight coil 36 is disposed on the entry side of the drum 2 . In the exemplary embodiment, the multiple or multi-flight coil 36 includes two helical plates which are disposed in such a way as to be offset relative to one another in terms of rotation. Other plates may also be provided. The coil 36 is disposed on the inside of the drum 2 and is constructed in such a way that at least two coil portions overlap one another at each point on a drum bottom. Moreover, the Bides of the coil, that is to say the plates, are relatively high. This ensures that the solids R introduced through the feed device 6 are braked and do not fly or shoot through the screening device 1 , without the solids undergoing screening.
The multi-flight screen having a plurality of rods 8 , which is described in relation to FIG. 4, may replace the spiral screen 10 of FIG. 3 without any restriction.
The screening device described herein is distinguished by a very simple and robust construction and, at the same time, ensures fault-free operation, without blockages occurring. Critical aspects for ensuring reliable operation are the construction of the screening device with the helically wound rod 8 or with the rods 8 , the differences brought about by the curvature of the spiral 10 in the distance between the turns, the reliable separation of elongate solid fragments by virtue of the preceding aligning device and the automatic transport of the solids R which is due to the rotational movement and spiral movement.
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A pyrolysis plant for refuse and a method for screening solid residues provide a sure and trouble-free sieving of a solid material using a sieving device having a configuration which is as simple as possible. A spiral formed by a rod which is wound in a helicoidal manner, or a plurality of such rods, are provided as the sieving device. The rod or rods can rotate around a longitudinal axis. The solid material is introduced into an interior formed by the rod for sieving, preferably with the assistance of an aligning device for longitudinally extended solid material parts. The spirals include, in particular, a bend so that the lodged solid materials can automatically detach themselves. The sieving device is especially suited for sieving pyrolysis residual material.
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BACKGROUND OF THE INVENTION
The invention relates to a composite driving belt provided with a carrier and a plurality of transverse elements assembled slidably thereon.
DESCRIPTION OF THE RELATED ART
Such Belt is generally known, e.g. described in U.S. Pat. Nos. 3,720,113 and 4,080,841. In the known belt, a carrier, alternatively denoted tensile element or tensile means, is composed as a package of a number of endless metal bands. The known belt may in particular be applied in a variable transmission, whereby the driving belt runs over pulleys, the substantial conical sheaves of which are adapted to be displaced axially relative to each other so that the running diameter of the driving belt over the pulley may vary. In turn, while the belt is in operation, the carrier or band package slides over a contact face, the so-called saddle part of the transverse elements. Also, the separate bands of the package slide relatively to each other during operation.
In practice the driving belt, in particular each of the bands, is under a very high tension, on the one hand to ensure a proper frictional contact between the pulleys and the transverse elements and on the other hand to properly conduct the transverse elements in the straight part of the driving belt, i.e. to prevent the belt, in particular the transverse elements in the straight trajectory part of the belt from splashing apart.
The known belts of the current type perform satisfactorily, however may be applied in a transmission environment where the lubrication oil is not of a type optimal for CVT due to standardisation at a manufacturer, may also be applied where mechanical parts are for sake of costs not chosen such that gears are incorporated in an optimally meshing manner or, alternatively, the gears are incorporated non-pretensioned in the transmission. Also where costs are saved on isolation of the engine and transmission room, irritating noise may arise from the drive train of a vehicle and may disturb the driver thereof. The sounds of such noise is known to originate from gear wheels within the drive train of the vehicle, rotating impaired during operating of a vehicle and is commonly denoted “rattle” or “gear rattle”. Also the term “scratch” is used.
SUMMARY OF THE INVENTION
The present invention seeks to contribute to the solving of such rattle problem by providing a belt design which is not prone, at least considerably less than the known belt, to urge meshing gear wheels into a state of vibration causing the rattle.
According to an idea and a tribological insight underlying the invention and considered part thereof, the belt may during operation of a drive train run in varying conditions, influencing the coefficient of friction in the frictional contact between the carrier of the belt and the transverse elements thereof. With a belt construction in accordance with the invention, it is effected in accordance with the tribological insight underlying the invention, that the belt will run in a condition where the coefficient of friction is no longer, at least considerably less prone to change in operating conditions. In this manner, be it to the extend of some efficiency loss of the belt performance, the belt may be incorporated in a drive train with a view to solving the “rattle” problem thereof.
In particular the roughness of each contacting surface of element and carrier is produced in such roughness that this factor becomes dominant over other factors influencing the lubrication state. E.g. by the relatively high peaks which may be recognised in a high Ra value surface, the lubricating oil will be influenced such that even at high relative speeds, or even with a hydrodynamic or full film lubrication promoting shape of the element contact surface, the oil film in between the contact surfaces will remain of such nature that a boundary lubrication, i.e. with a high coefficient of friction will remain in tact for most of the operating conditions, at least for the conditions where transmission systems are critical to scratch excitation.
The latter condition may in accordance with a specific embodiment of the invention further be promoted, by the omission of a wedge shaped entry space between the element contacting face and the carrier, i.e. other than caused by ordinary facet rounding, e.g. realised with the substantially flat shape of the saddle part of a transverse element, it is achieved that lubricating oil within the contact between saddle carrier will only be available to an extend causing so called boundary lubrication. In this lubrication state a relatively constant coefficient of friction occurs. By the shape of the saddle, it is prevented that oil accumulates before such contact in a manner that an amount of lubricant causing a mixed or a full hydrodynamic lubrication may enter the actual location of contact between carrier and element saddle.
In a so called mixed lubrication state, also in accordance with an insight underlying and part of the invention, the friction coefficient changes with changes in relative speed between carrier and transverse element. Thus in a further elaboration of the invention the distance between saddle and the so called mutual rocking edge of elements within a belt is set lower than 1 mm, preferably the rocking edge is set between 0.4 and 0.8 mm below the saddle. In this manner the maximum relative speed between the element saddle and the carrier is made lower so that by this measure, the maintenance of a boundary lubrication state is yet further promoted.
In yet a further embodiment in accordance with the invention, the lubricating oil used in conjunction with the belt is set to a very low viscosity, thereby impeding the coming into existence of a boundary or full lubrication state between element and carrier.
Thus the invention not only relates to a belt and transmission with any of the above measures, however, in particular to a belt and transmission in which the high roughness feature is combined with any one or more of the above provided set of measures.
The boundary lubrication state is in accordance with the invention preferred over the hydrodynamic lubrication state of operation of the belt since it was established by the investigations underlying the invention that the relative speeds within a belt running in a transmission, may drop to zero so that the HL lubrication condition can not in all operating conditions be maintained. Rather the friction coefficient appears to change from relatively low to relatively high with relative speed within the belt, i.e. amongst others with the instantaneous transmission ratio of the belt, together with the lubrication state in the belt which appears to dynamically shift from a hydrodynamic lubrication state, via a mixed lubrication state to a boundary lubrication state and vice versa. Thus, in accordance with a further aspect the belt is designed such, in particular is provided with such a roughness that, at least in the LOW transmission mode, the boundary lubrication state will remain, at least the coefficient of friction remains virtually constant over a considerable range of primary shaft revolutions when the belt is applied in a transmission. The LOW transmission state is in accordance with further insight underlying the transmission preferred over the OD state where also extreme relative speed differences may occur in the belt, since it is recognised that most transmission systems feature less vulnerability for scratch in this a transmission mode.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now further be explained further by way of example along a drawing in which:
FIG. 1 represents a single ring of prior art belt, adapted in roughness in accordance with the present invention;
FIG. 2 is a tribological graph for the belt realised by research underlying the invention, and providing the insight upon which the invention is based;
FIG. 3 is a schematic representation of an insight underlying the present invention, abstractly reconsidering the components of a belt in analogy to frictional physics;
FIG. 4 represents a radial cross section of a belt, showing a transverse element and the tensile means cross section
FIG. 5 is a cross section of the transverse element along the line V—V in FIG. 4 , while
FIG. 6 more in detail provides the cross section of the so-called saddle part in FIG. 5 , to be applied in accordance with the invention at a defined roughness, preferably in combination with the carrier part of FIG. 1 ;
FIG. 7 is a displacement graph of a block m of the model in accordance with FIG. 3 , as a function of time during stick-slip behaviour;
FIG. 8 is a schematic illustration of the interaction between a push belt transmission and meshing gear wheels of a drive train.
FIG. 9 is a representation of characteristic belt and transmission feature realised by the invention.
In the figures corresponding components are denoted by identical references.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 represents a ring of a drive belt, in particular push belt as commonly known. The ring may be part of a carrier of form the same, however is in common applications like automotive personal vehicle and trucks, utilised in a nested arrangement of a plurality of circumscribing loops or rings, as may e.g. be taken from FIG. 4 . Such a set of nested rings forms part or all of the belt's tensile means along which transverse elements are disposed freely moveable in the endless longitudinal direction of the belt. The elements are clamped between the sheaves of a set of pulleys and transmit rotation from one drive pulley to a driven pulley. The tensile means thereby serves to keep together the transverse elements pushing against each other. In the present example both the transverse elements and the tensile means are composed of a metal.
When the driving belt runs over pulleys having different running diameters, the variable bands of the band package have a mutual speed difference, at least in situ of one of the pulleys. This speed difference may in practice be more than 0.4 meter per second between two successive bands disposed around each other. Moreover, notably the inner bands of a carrier are pressed on to each other with substantial force, since the pressure force on a band is built up by all bands disposed outside i.e. there around.
By providing in particular the more inwardly disposed bands at least at one side with a surface profiling, through which an improved lubrication between the bands will be produced, less wear and increased life time is promoted. Preferably, the surface profiling comprises grooves, which in practice provide good results. According to a further feature, the roughening value of the surface profiling lies between 0.30 and 0.75 μm Ra, here measured according to CLA method, and preferably between 0.46 end 0.55 μm Ra. In a preferred embodiment the roughness is achieved by grooves disposed in crossing sets. The grooved profiling of a metal band is achieved by rolling a band between rollers, one roller being fitted with a surface profiling on the circumferential surface.
The drawing in FIG. 1 diagrammatically shows an endless metal band. The width of such a band may e.g. range between 5 and 20 mm and the thickness between 0.15 end 0.25 mm. The diameter of the band in circular condition may e.g. range between 150 and 400 mm. The endless band has an exterior side 1 and an interior side 2 . In the known embodiment of FIG. 1 , the interior side 2 is provided with a surface profiling of crosswise disposed grooves. According to a preferred embodiment of the invention all rings of a belt's tensile means are incorporated in this manner.
It is further derived from the investigations underlying the current invention that for achieving an anti-scratch adapted belt a specific, combined set of measures related to the manner of contact and the lubrication of the contact between a carrier face and the saddle is required. According to this set of measures, for lubrication of this contact, it should be promoted that a restricted amount of lubrication, i.e. oil occurs between element and carrier, the so called boundary lubrication, in combination with a relatively very much roughened surface area of both contacting faces, i.e. saddle face and the inner band facing of a carrier in order to prevent separation, ergo to maintain bounding lubrication. According to the invention, primarily, the smoothening, expressed in roughness parameter Ra, of both faces should be such that the so-called reduced roughness Ra′, i.e.
Ra′=SQRT ( Ras 2 +Rar 2 ) (1)
In which
Ra′=the combined roughness parameter
Ras=the average roughness parameter of the saddle surface expressed in Ra.
Rar=the parameter for the average roughness of the inner ring face contacting the saddle.
SQRT=square root of ( . . . )
meets the requirement to be greater than 0.6 μm, preferably to remain within the area over than 0.75 μm.
FIG. 2 diagrammatically reflects a curved typical relation according to the invention between a friction coefficient or parameter, linearly parameterised along the Y-axis of the figure, and a “belt and oil features” parameter L, alternatively Lubrication number L, logarithmically expressed along the X-axis. The parameter L is calculated utilising the dimensionless number
L = η 0 V r p a v R a_ ′ ( 2 )
in which:
L=a lubrication number or parameter in accordance with an insight underlying the invention;
Vr=the relative speed between the two contacting surfaces, here of the inner belt ring and a transverse element's saddle;
η 0 =the dynamic viscosity parameter of the lubricating medium at ambient pressure;
Pav=the average Herzian stress within the band/saddle contact;
Ra′=the combined surface roughness of both saddle and ring surface as calculated by equation (1) above.
The combined surface roughness Ra′ is calculated in the ordinary manner in the art provided above, and expressed in roughness coefficient Ra′.
The principal characteristic of the curved relation given by formula 1 and FIG. 3 is according to the invention determined by dominant parameters Vr, and Ra, whereas the viscosity and the average Hertzian pressure parameters are in accordance with the insight according to the invention not, at least not directly related to design parameters of the belt. The lubrication number L equation (2) according to the invention more in particular reveals that relative speed Vr is the most dominant factor for influencing the friction coefficient due to changing operation conditions, since also Ra is given once the belt is set into operation.
FIG. 2 shows in accordance with experimental results of research underlying the invention and matching the parameter line depicted in FIG. 2 , that the relation between an actual friction coefficient and the lubrication parameter appears to typically follow a curve with three main sections. In the first section BL, suggestedly where so called boundary lubrication, i.e. shearing contact exists between the two contacting surfaces, the friction coefficient is virtually constant with increasing parameter L. In a second section ML, suggestedly where mixed lubrication and friction occurs, the friction coefficient drops with increasing L number, typically from somewhere like 0.16 to somewhere like 0.01. In the third section HL, where suggestedly hydrodynamic lubrication exists, i.e. with shear occurring within the lubricant and not between the contacting surfaces, the actual friction parameter has it's lowest value and again is virtually constant or may slightly increase again with increasing value of L. This section may more accurately also be denoted elasto hydrodynamic lubrication EHL.
FIG. 4 provides a cross section of a belt and a view of a transverse element, depicted according to a view in the longitudinal direction of the belt. FIG. 5 is a transverse cross section thereof over the line V—V, with the tensile means being omitted from the drawing, providing a view in a belt's axial direction. FIG. 6 in an enlarged scale depicts the in FIG. 5 encircled part of the element, in fact the part which contacts the inner face of a belts tensile means, the so called saddle of an element. In this element the roughness Ra is a part of a set of measures increased considerably over the roughness value of known commercialised belts, including an increase in roughness of the carrier.
It is a further prerequisite in accordance with the invention that for achieving the desired condition in the mutual contact, the local bending radius Rb of the band, i.e. tensile means, and of the saddle Rs should preferably be equal, thus:
Rb=Rs (4a)
Since this requirement in the practise of an operating belt can not be achieved, the design in accordance with the invention should at least fulfil that:
Rs>Rb (4b)
In accordance with a further aspect underlying the invention, the combined local radius, i.e. the reduced radius of both the saddle and the tensile means is taken into consideration by the requirement:
1 /Rr =1 /Rs +1 /Rb (5)
in which
Rr=the reduced radius of a Carrier and Saddle face contact Rs=the local radius of the saddle measured in mm Rb=the instantaneous radius of the band measured in mm
It is in accordance with the invention considered that for most applications of a belt, generally Rs should range over 80 mm, whereas, whereas Rb for commonly applied transmissions typically ranges between 25 and 80 mm during operation of the Belt. For preventing that oil accumulates in the contact between carrier to an amount causing the described ML and HL lubricating conditions the element is shaped so as to avoid a wedge shaped spacing between carrier and saddle (like e.g. present in the embodiment according to FIG. 6 . Since the running radius of the belt varies with the transfer ratio of the transmission, flat is defined such that any possible concave shape in the cross section of the saddle should be of a radius substantially higher than the largest running radius specified for the belt or occurring within a transmission in which the belt is to be incorporated.
Both radii are taken in accordance with the radial and longitudinal direction of a belt, considering the normal operation and configuration thereof in a pulley. More in particular it is considered that for obviating the said wedge shaped entry space at the largest amount of possible contacting locations on a saddle, without preferably the radii of saddle and band becoming equal, the saddle is preferably shaped with a non-continuous i.e. edged transition in a possible contacting surface, since from experience underlying the invention it is known that these will break, i.e. remove the lubricated condition in the mutual contact.
For even better performance of a belt and transmission in accordance with the invention, the invention provides to apply a lubricating medium in the form of an oil type having a dynamic viscosity η lower or equal to 4 MPa*s at a nominal temperature of 100 degrees Celsius. In this manner “L” is reduced further, so that the change in lubrication condition from the BL area to the ML area in the graph is shifted to the left, i.e. the ML is even further reduced. By applying all or a majority of the different measures of the set provided by this invention the operation of a belt is optimised, for solving a scratch problem of a transmission.
In the latter respect, according to an even further aspect of the invention and preferably taken into account in the set of specific measures in accordance with the invention, the so-called rocking edge of the belt is provided less than 1 mm from the saddle surface, more in particular in a range between 0.4 and 0.8 mm below the saddle surface. In this manner it is achieved to decrease the relative velocity Vr between saddle and tensile means, alternatively denoted carrier, in particular at the extreme OD and LOW ends of the range of ratios in which the belt will operate. In combination with any, preferably all of the previous measures this measure appears to diminish the occurrence of so called rattle in a transmission, at least the transmission appears to become less prone to being urged into such state, be it to the expense of some loss of efficiency in performance of the belt, in particular in the LOW and OD areas of the belt's range of transmission ratios.
FIG. 3 illustrates a mathematical model taken into consideration and developed at developing the insight underlying the claimed invention, of the friction occurring within the belt. In the model, it shows that changing the friction force F w =μF N , will lead to changes in the spring force F s =kx, which may lead to vibrations if the damping force (F d =c{dot over (x)}) is not sufficient. It has been distinguished between dynamic frictional behaviour due to external excitation and self (or internal) excitation. The value for the friction force F W is in this model interchanged with a result of two factors: coefficient of friction μ and normal force F N (considered that F w =μF N ). The external form can lead to vibrations due to a (periodical) change in normal force, e.g. F N (t)=sin(ωt). For example the pressure fluctuations in the pulleys will lead to a change in normal force with time in the contact between saddle and ring in the CVT.
Attention will now be paid to the self or internal excitation form, which in accordance with the idea underlying the invention, may lead to vibrations due to a change in coefficient of friction with relative velocity.
In case of self excitation ‘Classical’ stick-slip, where the coefficient of friction changes when going from static to kinetic friction, is distinguished, as well as Stick-slip-related, or μ k −V r dependent behaviour, where in a system already in motion (only slip) the kinetic coefficient of friction changes with relative velocity V r .
Classical stick-slip arises when the coefficient of static friction is greater than the coefficient of kinetic friction. In the model of FIG. 3 , the block with mass m will stick to the lower surface if the coefficient of friction is sufficiently large at the equilibrium position when moving it along with an absolute velocity of value {dot over (x)}=V. During the stick period the force relationship may be written as
cV+kx<μ s F N (6)
During the stick, the spring force increases with time at a rate kVt (or kx) as the slider is displaced from point A to point B as indicated in FIG. 7 . Up to point B, the static friction force is capable of withstanding the combined restoring forces consisting of the constant damping force cV and the increasing spring force kx. At point B, the restoring forces overcome the static friction force μ s F N and slip occurs to point C.
Considering the slip-phase the motion of the mass or block “m in FIG. 3 is described by the equation
m{umlaut over (x)}+c{dot over (x)}+kx=μ k F N (7)
It is assumed that at a certain moment μ k decreases with increasing relative velocity V r according to hydrodynamic action effects in the lubricated contact. For the moment only the dependency of μ k with V r is considered. An extension to other parameters of influence, important for design recommendations, will be given further on.
As a first approximation the dependency of μ k with V r can be modelled by a linear relationship with a certain negative slope (α) according to
μ k =μ k 0 −αV r (8)
The expression (8) for μ k can be substituted in equation (7), with
V r =V−{dot over (x)} (9)
which yields the following equation
m{umlaut over (x)} +( c−αF N ) {dot over (x)}+kx =(μ k 0 −αV ) F N (10)
In accordance with the insight underlying the invention, the slope α has been introduced in the damping term. Here it acts in a negative way. A negative damping coefficient feeds energy into the system and makes vibrations and even resonance possible. It is thus demonstrated by the development underlying the current invention that when the resulting amplitudes and frequencies match certain critical system characteristics of the gear set gear rattle will occur.
It is also demonstrated that unlike what quite often is assumed, stick is not a necessary condition for the occurrence of rotational vibrations. Rather the behaviour of the change in coefficient of friction with velocity may lead to these vibrations. Furthermore it should be noticed that any disturbance in the transmission may lead to excitation of the mass-spring-damper-friction system due to the inherent unstable nature of this system.
Further in accordance with the idea underlying the invention, the mass-spring-damper-friction model is applied to the push belt/variator, at which, e.g. in Low, the following simplification is made regarding the belt and transmission as shown in modelled FIG. 8 . In the dynamical system of the variator only relative motion between saddle and ring, as source, and vibrations of the secondary axis in the variator, as effect, are considered. The absolute movement of a stating belt is here not taken into consideration since, in accordance with the insight underlying the invention it does not play a role in triggering transmission scratch.
The mass, in particular the vibrating mass in the model according to FIG. 8 is represented by the secondary axis in the transmission according to the invention. The element string constitutes the spring when the stiffness is considered and also plays a damping role. The element string will be formed by different elements in time due to the dynamic nature of the system. Two situations can be distinguished. The first situation is defined in that the element string is not loaded in a way that compressive forces are able to overcome the endplay (the so-called ‘lose part’). The second situation is when there is no play, i.e. end play, in the belt anymore, which is the case in the ‘push part’ occurring during operation of the belt. According to the first situation, when there is some amount of endplay in the element string, this part, which is considered to feature certain stiffness and damping, does not have to be taken into account. However in the second situation, when there is no endplay, this part, having a characteristic stiffness and damping, is however considered in the model developed in accordance with the ideas underlying the invention.
Friction occurs between the saddle and ring on the primary pulley. The normal force in this contact is the parameter F N used in the model. The ring is moving relatively to the elements in the primary pulley with a certain relative velocity V. The overall relative velocity Vr, i.e. V superimposed with vibration {dot over (x)}, which is crucial for the frictional behaviour, is according to equation (9).
At applying the developed model to predict the amplitudes and frequencies of vibration, it is considered that the gears limit this vibration form by means of the play that exists between the teeth of the gears pertaining to a transmission according to the invention. Therefor two situations are distinguished. First, if the amplitude of vibration is greater than the play between the gear teeth, gear rattle may occur two sided. Second, if this amplitude is smaller then gear rattle may occur single sided.
The gear set as shown in FIG. 8 is only for illustrative purposes. It will be explained using the model described along FIG. 3 , while the individual effects of changes in the governing operational variables are in accordance with the invention identified. The following variables are identified:
m—mass of the secondary axis c—damping coefficient k—spring stiffness of the element string F N —normal force in the saddle-ring contact μ k —kinetic coefficient of friction dependent of the tribology in the saddle-ring contact
The combination of the items mentioned above is responsible for the system behaviour regarding rotational vibration. The last item, which concerns the influence of tribology aspects on the kinetic coefficient of friction, has been paid special attention to. In the lubricated saddle-ring contact the coefficient of friction is a dynamic parameter depending on variables like relative velocity, viscosity, temperature, pressure and roughness.
Another important parameter is the play between the elements. If there is some amount of play, e.g. in case of the so called ‘lose part’ of a belt operating in a transmission and when the amplitude of the vibration is not exceeding the play, the stiffness and damping of this part do not have to be taken into account. Then only the stiffness and damping of the push part have to be considered.
The dynamic behaviour of the coefficient of friction is represented in the tribological curve for the push belt (FIG. 2 ). In this curve the coefficient of friction is mapped as a function of the dimensionless number L defined by equation (2), utilising the combined roughness defined in equation (1).
In equation (11), the lubrication number L is incorporated, instead of only in the motion equation. This yields
m x ¨ + ( c - αη 0 p a v R a F N ) ︸ 1 x . + k x = ( μ k 0 - αη 0 p a v R a V ) ︸ 2 F N ( 11 )
Equation (11) shows two counteracting terms when vibration is concerned. The equation makes clear that the amplitude of vibration increases if term 1 decreases and/or term 2 of equation (11) increases. Therefore the parameters in term
αη 0 p a v R a
have both a positive and negative effect on the amplitude. The net result follows from the governing system parameters.
In the above representation of the tribological curve for the belt, the hydrodynamic action of the contact is assumed. I.e. increase in hydrodynamic separation, i.e. film thickness over roughness, leads to a decrease in the coefficient of friction, i.e. leads to a shift from a boundary lubrication state (BL) to a mixed lubrication state (ML) for low values of L and assuming that friction is constant in the boundary lubrication regime. In FIG. 9 it illustrates that with at least a plurality of the measures of the set provided by the invention, a high coefficient of friction is maintained for a considerable part of a common range of rotational speeds of the primary shaft. The belt hereby runs in a LOW transmission ratio, which appeared the most scratch triggering transmission mode. The belt feature illustrated in this graph comprises that the friction coefficient remains virtually constant, i.e. does not decrease more than about 10% up to a predetermined value of the speed of the primary shaft, here over a major part of the transmissions regular range of transmission ratios. In this FIG. 9 the dotted line illustrates the dependency of the coefficient of friction without any of the measures according to the invention being taken.
In a preferred embodiment of the invention so much of the set of measures is applied such that the critical constant high value of the friction coefficient is maintained up to a primary speed value of 4000 RPM, More preferably however, this state is maintained in the said LOW transmission mode up to 6000 RPM.
The invention further relates to all details of the figures pertaining to the description and all features defined in the following claims.
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A composite driving belt provided with a carrier and a plurality of transverse elements assembled slidably thereon, the carrier including one or more bands, preferably composed of a plurality of endless metal bands disposed radially around each other, each element being provided with a radially outward directed carrier contact plane for contacting a radial inner contact plane of the carrier while in operation, wherein the contacting plane of the transverse element is shaped by an substantially flat surface, while the inner contacting face of the carrier contacting the contact plane the element has a profiled surface, the combined roughness Ra′ of both surfaces being more than 0.6 μm, preferably over 0.75 μm. In particular the roughness and shape of the relevant contacting faces of a belt are adapted to achieve a boundary lubricating condition, while the lubricating oil is defined to meet the requirements of prohibiting the occurrence of scratch, at least reducing the urging thereof considerably.
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FIELD OF THE INVENTION
The present invention relates to routing multimedia sessions within an automatic call distributor. More particularly, this invention relates to routing multimedia sessions using declarative automatic call distributor routing with service level optimization.
BACKGROUND OF THE INVENTION
A contact center is defined as a set of queues, onto which “calls” arrive, which may be phone calls, video calls, email, chat messages, instant messages and the like, and by a set of agents, who may answer the calls in some of the queues. Calls are stored in multiple queues for two reasons. On the one hand, by associating the right agents to each queue, the handling of each call can be optimized both in quality and in time. Therefore, a skill level is often associated to each pair, the agent and the queue, that is used to optimize this agent-to-call matching. On the other hand, calls are also separated into different queues to ensure different qualities of service depending on the expected value of the call from the company's (owner/operator of the contact center) point of view. The quality of service is defined by one or more service level agreements (SLA) that specify that a given percentage of the calls must be answered within so many seconds. Using these two requirements, it is common to assign agents to queues in order to optimize the handling of calls and to ensure the relative independence of the quality of service. However, a direct application of queuing theory shows that the efficiency of the contact center, measured by its throughput (number of calls answered per hour), is maximized by allowing agents to work on as many queues as possible. A multi-skilled workforce is more flexible, thus the idle time that is necessary to reach a given quality of service is reduced.
The dilemma to solve when routing calls is, therefore, to allow the flexibility and the throughput of a multi-skilled contact center, while ensuring the independence between the queues from a service level agreement point of view. This is a difficult problem because automatic call distribution (ACD) routing falls into the domain of on-line algorithms. Practical on-line algorithms are difficult to develop for many reasons. First, real world event distributions are regular but hard to predict. In the case of a contact center, this means that the call distribution can be characterized but the standard deviation is high. Moreover, the multi-skill aspect adds a combinatorial nature to the routing problem. Combinatorial stochastic problems are tricky because the combinational aspect yields a non-linearity that invalidates most statistical analysis techniques and produces a chaotic behavior.
Real world ACD routing algorithms use dynamic heuristics and simple, rule-based selection of calls and agents. Queues and calls may be assigned priorities, which are taken into account by the selection rules, among many other criteria such as skill level, priority and arrival time. In a multi-skill environment, finding the right number of agents for each queue, referred to as dimensioning, is done through simulation, and the weights may be finely tuned to obtained the desired SLAs. However, the variability of the problem makes this tuning quite difficult. Classic heuristics, such as first-fit and best-fit, do not provide the flexibility to guide routing based on SLAs. Using a first-fit process, when a new call arrives, or when an agent becomes available, the algorithm polls each queue until a match is found. The first match is returned. Best-fit is similar to first-fit, except that all matches are considered and the best one is returned. A commonly used heuristic for best-fit is to return the least qualified agents for a new call, and the most urgent call for a newly freed agent. Using the least qualified agents, as based on the agent's queue list and the agent's skill levels, maximizes the probability that another call may be handled by a more qualified agent later.
A solution has been proposed called service level routing (SLR). SLR routes calls according to SLAs by dynamically adjusting the size of the group of agents that can work on a given queue based on the current SLA satisfaction. A manner of implementing SLR is to sort a list of agents from less flexible to most flexible for each queue, and the most flexible agents may be temporarily removed from the list when other queues have more stringent SLAs. Where SLR is effective in meeting constraints associated with SLAs, there is a trade-off between meeting the SLAs and throughput of the contact center. By focusing primarily on meeting SLAs, SLR often suffers from reduced throughput.
It is desirable to control the routing algorithm by only stating the SLAs. Such a situation is referred to as declarative control. One method of implementing declarative control is reactive stochastic planning (RSP). RSP uses a planner to maintain a schedule that mixes the existing calls in the queues and forecasted future calls. This schedule is maintained regularly and is used to guide a best-fit algorithm that tries to reproduce what is forecasted in the schedule. This is a sophisticated method of implementing a reservation mechanism. Unfortunately, RSP plans for a worst case future that rarely, if ever, occurs in practice. As a result, resources can periodically be mis-allocated using RSP.
What is needed is an improved method of routing calls within a contact center by stating the service level agreements. What is also needed is a method of improving throughput of the contact center while meeting the service level agreements.
SUMMARY OF THE INVENTION
An embodiment of the present invention includes a method of determining a current rate of satisfying a service level agreement constraint, wherein the service level agreement constraint is associated to selected ones of each incoming contact within a contact center, comparing the current rate to a target rate associated with the service level agreement constraint to calculate a satisfaction value, measuring a size of a queue associated with the service level agreement constraint, and calculating a potential value associated with the service level agreement constraint based on the satisfaction value, the queue size and a weighted priority level associated with the service level agreement constraint. The contact center includes one or more agents and one or more queues such that each service level agreement constraint is associated to one of the queues, and each agent is associated with one or more of the queues. Preferably, a skill level is associated to each agent for each queue, a skill level is associated to each contact, and a skill constraint is associated to each queue such that each contact is answered by an agent with skill level equal to or greater than the skill level associated with the contact. After a predetermined time frame, if the contact is not answered by an agent, then the skill constraint associated with the contact can be by-passed.
The method can also include calculating a potential value associated with one of the one or more queues by summing the potential values of all service level agreement constraints associated with the queue. The method can also include signaling that an agent is available, sorting a list of queues associated with the available agent according to the potential energies of the queues, selecting a non-empty queue with the highest potential energy from the list, and routing a first contact in the selected queue to the available agent. The first contact can be determined by which contact arrived in the selected queue first. The first contact can be determined by selecting a contact from the selected queue that minimizes a combination of delay and a contact priority weight. The method can also include calculating a potential value associated with one of the one or more agents by summing the potential values of all queues associated with the agent. The method can also include associating a new incoming contact to a queue, sorting a list of agents associated to the queue according to the potential energies of the agents, and routing the contact to an available agent on the list with the lowest potential energy. The method can also include routing the contact to the queue if no agents on the list are available. The method can also include placing the contact on hold and associating a wake-up time to the contact, awakening the contact after the wake-up time has elapsed, and routing the contact to an available agent with the lowest potential energy.
The satisfaction value is preferably calculated by a discontinuous functional relationship between the current rate and the target rate. The functional relationship is preferably defined by: f(a,b)=(100+|a−b|), for a≦b, and f(a,b)=(|a−b|)/20, for a>b, where a is the current rate and b is the target rate plus a tuning factor. The current rate is preferably determined by calculating the ratio of the sum of all contacts associated with the service level agreement constraint that were picked-up within a given past time frame and that satisfied the service level agreement constraint plus the sum of all contacts in the queue associated with the service level agreement constraint that can still satisfy the service level agreement constraint, and the sum of all contacts associated with the service level agreement constraint that were picked-up within the given past time frame plus the sum of all contacts in the queue associated with the service level agreement constraint. The potential value associated with the service level agreement constraint is preferably calculated by multiplying the weighted priority level associated with the contact and the sum of the queue size divided by a tuning factor plus the satisfaction value. The service level agreement constraint for each contact can be satisfied when the agent receives the contact within a predetermined pick-up time. The queue size can define the number of contacts within the queue that have yet to be picked-up by an agent associated with the queue. The contact can be one of a telephone call, a video call, an email, a chat message, and an instant message. The service level agreement constraint can include a pick-up time and the target rate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a conventional function for scoring a comparison between a current rate and a target rate.
FIG. 2 illustrates a function for scoring a comparison between a current rate and a target rate according to the preferred embodiment of the present invention.
FIG. 3 illustrates a method of handling a newly received call event according to the preferred embodiment of the present invention.
FIG. 4 illustrates a method of assigning a newly freed agent to a call according to the preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Embodiments of the present invention use a method called service level optimization, or SLO. SLO is a constraint-based heuristic that is based on the principle of a service level agreement (SLA). The SLO methodology is used in place of conventional call routing methodologies in an ACD to more efficiently provide high throughput while meeting SLAs. SLO makes routing decisions based on objects that represent the SLAs. Each SLA is an active constraint with a potential function that yields a dynamic priority for each queue and a potential value for each agent. When compared to conventional routing methods such as first-fit, best-fit, SLR and RSP, embodiments of the present invention can provide the same level of satisfaction using fewer agents, or can provide a higher level of satisfaction using the same number of agents.
The SLO methodology is preferably utilized in a multi-queued, multi-skill call center. A “call”, or contact, can be multimedia in nature, such as a telephone call, a video call, an email, an instant message, or a chat message, and can also be considered a multimedia session. As such, the call center can also be referred to as a contact center. It is understood that other types of contact methods can be utilized by the present invention.
A call center includes an ACD for receiving and routing calls. Each call is routed to one of many queues where the queues are manned by a set of agents. To design a call center, all SLAs are first defined and then the ACD is tuned to meet the requirements of the SLAs. In the preferred embodiment, the ACD utilizes the SLO method to assign calls to agents and/or queues based a specific prioritization scheme. The SLO prioritization scheme is discussed in greater detail below.
Each queue is preferably assigned a different type of call, such as telephone call, email, or a chat message. The type of call can be further broken down based on the reason for the call, such as help desk, activation, or billing, each of which can be characterized by an anticipated processing time. Each type of call can also be characterized by its priority level, such as VIP or regular, as is preferably defined by the SLAs. As can be seen by the variety of possible queue types, the queues display various trade-offs, such as email versus telephone, long processing times versus short processing times, or VIP customers versus regular customers. Each queue is assigned one or many SLAs.
SLAs are preferably defined by two numbers, a pick-up time and a satisfaction target rate. For example, 80% of the calls, in this case email, are answered (picked-up) in less than 10 minutes, or 95% of telephone calls are answered in less than 20 minutes. Each SLA is also assigned a priority level. Preferably, there are three levels, low, medium, and high. The low level is assigned a value of 3, the medium level is assigned a value of 2, and the high level is assigned a value of 1. The value of each priority level is set according to the strategy of the company using the service of the ACD, based on the perceived value for each call. It is understood that more or less than three priority levels can be used and that the assigned value of each priority level can be any chosen value.
A call center is defined by a set of queues, onto which calls arrive, and by a set of agents, who answer calls in one or more queues. Each agent can be assigned to one or more queues. If the agent is only assigned to one queue, then that agent is said to be uni-skilled. If the agent is assigned to multiple queues, then that agent is said to be multi-skilled. Multi-skilled agents are more flexible than uni-skilled agents. The more flexible the agents, the more throughput of calls through the call center is possible. A skill level is associated to each agent for each queue and to each call, using a similar 3-valued notation as the SLA priority level (low, medium, and high). Preferably, a skill constraint is associated to each queue such that a call can only be answered by an agent with skill level equal to or higher than the skill level required for the call, until a given period has elapsed and no adequate agent is available, at which point the skill constraint is lifted.
The SLO methodology uses a dynamic routing algorithm based on a mathematical analysis of the SLA constraints. The mathematical analysis assigns a potential value, referred to as an energy value, to each of the SLAs. An energy value for each queue can be determined by summing the energy values of all SLAs associated with that particular queue. An energy value for each agent can also be determined by summing the energy values of each queue associated with that particular agent. Preferably, the higher the energy value, the worse the performance. Based on one or more of these calculated energy values, calls and agents can be dynamically allocated to efficiently meet the SLA constraints. The dynamic routing algorithm is essentially constraint-based where the constraints are defined by the SLAs. The constraints are considered active objects since the routing algorithm is able to evaluate how well each constraint is being met at any given time. Based on this dynamic evaluation, a score corresponding to a current energy value is generated for each SLA. With this score, the dynamic routing algorithm makes a determination as to which agent picks up a given call, or which queue a call is placed into.
The following notations are used in describing embodiments of the SLO method of the present invention:
E = {e 1 , . . . , e x } is a set of incoming call events; for each event e:
e.date
the time at which the call arrived into the ACD, measured
in seconds
e.queue
the queue onto which the call is placed.
e.skill
the skill level that is required for the call.
e.priority
the priority level assigned to this call.
e.pick
the time at which the call is initially picked-up by an agent.
A = {a 1 , . . . , a m } is a set of agents; for each agent a:
a.queues
the set of queues that agent a can service.
a.skill(q)
the skill level that is assigned to agent a for the queue q.
Q = {q 1 , . . . , q n } is a set of queues that can contain call events;
for each queue q:
q.size
the current size of the queue q (the set of call events stored
in the queue q).
S = {s 1 , . . . , s p } is a set of Service Level Agreements (SLA); for
each SLA s:
s.delay
the length of time before which the call is considered late.
s.rate
the target rate of calls that are answered within s.delay.
s.queue
the queue to which the SLA s applies.
s.priority
the priority level that is assigned to the SLA s.
skillDelay(q) is the time after which the skill level matching is lifted for a call placed on queue q.
A weighting scheme is also used to represent the relative strength of the various priority levels, s.priority. W(s.priority) is preferably an integer that represents the weight of priority level s.priority. Preferably, the weight of the high priority level, W(1), is ten times larger than the weight of the medium priority level, W(2), which is in turn ten times larger than the weight of the low priority level, W(3). That is, W(1)=100, W(2)=10 and W(3)=1. It is understood that other weighting schemes and values can be used.
The principle of the SLO method is to consider each SLA constraint s as an active object, to which an energy E(s) is associated. The energy E(s) provides a statistical means for defining efficiencies of the call center in meeting specifically defined objectives. Examples of such objectives include service level agreements, throughput of queues, and throughput of agents. The SLO method can then use the determined energy values to dynamically re-route calls within the ACD and improve the efficiency of the call center. The energy E(s) is defined by a score which is determined using the following formula:
E ( s )=[ f ( r ( s ), s .rate+ C )+ q .size/ D]*W ( s .priority) (1)
The higher the score of E(s), the worse the performance of the call center in meeting the SLA s. In general, E(s) is low if the SLA s is being satisfied, but E(s) is high if the SLA s is not being satisfied.
The energy of each SLA s is a product of the weight given to the priority level of this SLA s, W(s.priority), and the sum of the size of the queue to which the SLA s is associated, q.size, and a function f of the target rate, s.rate, and a dynamic satisfaction rate, r(s). A first portion of equation 1, f(r(s), s.rate+C), enables the SLO method to focus on queues that include SLAs that are not being met. A second portion of equation 1, q.size/D, enables the SLO method to focus on queues that include too many call events, that is, queues that have become too large and are therefore operating below efficiency expectations. C is a constant used for fine-tuning and is selected to overshoot the given target goal, s.rate. Preferably, C=3. D is also a constant used for fine-tuning. The value of D is dependent on the size of the call center. D is a means of weighting the relative importance of the queue size. Preferably, D=10. The function f provides a satisfaction value resulting from the comparison of the target rate to the satisfaction rate. Determination of the satisfaction value using the function f is described in greater detail below.
The dynamic satisfaction rate, r(s), is also referred to as a current rate. In determining the satisfaction rate r(s) it is important to evaluate calls that have already been answered and calls that are still in the queue waiting to be answered. The word “answered” in this context preferably refers to a call being picked-up, or received, by an agent. It is understood that in an alternative context, “answered” can refer to the call being resolved, the termination of the call, or some other measure. Some calls in the queue may have only just recently arrived into the ACD; however, other calls may have been waiting for so long that those calls are already late. Late calls are those calls that have already exceeded the pick-up time defined by the associated SLA constraint. Late calls still in the queue will ultimately reduce the satisfaction rate r(s) and therefore need to be accounted for. The dynamic satisfaction rate is computed according to the following:
r ( s )=[( X+Y )/ Z]* 100 (2)
where
X=|{eεE|e .queue= s .queue^ e .pickε[ t−A,t ]^ e .pick≦ e .date+ s .delay}|. (3)
Y=|{eεs .queue| t≦e .date+ s .delay}|. (4)
Z=|{eεE|e .queue= s .queue^ e .pickε[ t−A,t]}|+|s .queue|. (5)
A is measured in seconds, and r(s) is a rolling rate representative of the last A seconds. In general, X, Y and Z each represent a number of events that meet a defined condition. Specifically, X is the number of events on a specified queue that within the last A seconds were answered within the allotted time frame as defined by an SLA associated with the queue. In other words, since r(s) is the satisfaction rate for a specific SLA s, and since the SLA s is associated with a specific queue, s.queue, X is the number of events on s.queue that within the last A seconds were answered on time. In particular, X is the number of call events e, where e is a member of all call events that have occurred, E, such that the queue on which the call event e was placed, e.queue, is the queue, s.queue, associated with the SLA s for which the satisfaction rate r(s) is determined. Furthermore, the call event e must have been answered within the last A seconds, that is e.pick must be between a current time t and t−A seconds ago. Also, the call event e must have been answered within the time constraint defined by the SLA s, that is e.pick must be earlier than or equal to the time that the call event e arrived into the ACD, e.date, plus the time constraint of the SLA s, s.delay. Summarily, X is the number of calls associated with a particular SLA that were answered on time, within the last A seconds.
Y is the number of call events on the specified queue that have yet to be answered but can still be answered on time to meet the SLA constraint. In particular, Y is the number of call events e, where call event e is a member of all events on the queue s.queue, such that the current time t is earlier than or equal to the time that the call event e arrived into the ACD, e.date, plus the time constraint of the SLA s, s.delay. Summarily, Y is the number of calls associated with the particular SLA that are still in the queue and can still be answered on time.
Z is the total number of call events that have been answered on a particular queue within the last A seconds plus the total number of calls still in the particular queue. In particular, Z is the number of call events e, where e is a member of all call events that have occurred, E, such that the queue on which the call event e was placed, e.queue, is the queue, s.queue, associated with the SLA s for which the satisfaction rate r(s) is determined. Furthermore, the call event e must have been answered within the last A seconds, that is e.pick must be between a current time t and t−A seconds ago. Z also includes the number of call events e that are currently in the queue s.queue.
Once the satisfaction rate r(s) is determined, a value of the function f(r(s), s.rate+C) can be determined. The function f is a non-linear, non-continuous function that includes a rating technique for the satisfaction rate r(s). The function f is defined as:
f ( a,b )=(100+| a−b |), for a≦b (6)
f ( a,b )=(| a−b |)/20, for a>b (7)
Comparing equations 6 and 7 with equation 1, it follows that a=r(s) and b=s.rate+C. The function f produces a score based on the difference between the current rate and the target rate. Equation 6 is used when the current rate is less than or equal to the target rate. Equation 7 is used when the current rate is greater than the target rate. Optimally, the current rate equals the target rate. If the current rate is less than the target rate, then the function yields a higher score. Recall that when calculating the energy value E(s) for a given SLA s, a lower score is better than higher score. However, it is not desirable for the current rate to be greater than the target rate since this condition signifies an excess of resources, which is an excessive cost. Therefore, if the current rate is higher than the target rate, then the function also yields a higher score.
FIG. 1 illustrates a conventional function for scoring a comparison between a current rate and a target rate. As can be seen in FIG. 1 , the lowest score is obtained when the current rate equals the target rate. The function illustrated in FIG. 1 is continuous and “V-shaped” such that the score increases equally whether the current rate is higher or lower than the target rate.
FIG. 2 illustrates a function for scoring a comparison between a current rate and a target rate according to the preferred embodiment of the present invention. The function in FIG. 2 includes a discontinuity between scores where the current rate is less than the target rate and where the current rate equals the target rate. Also, the score increases at a lower rate as the current rate is larger than the target rate, as compared to the rate as the current rate is smaller than the target rate. The discontinuity and the reduced slope of the score for current rate larger than target rate is advantageous to improving the efficiency of the SLO method of the present invention. It is understood that the slopes of the function illustrated in FIG. 2 are for illustrative purposes only, and that the actual slopes can be different than that shown in FIG. 2 .
The energy associated with each SLA s, E(s), can be used to derive an energy value for queues and for agents. Since each SLA is associated to a specific queue, the energy value of a queue can be calculated by adding together all of the energy levels for each SLA associated with that queue. In other words, the energy for each queue q, E(q), is the sum of all energies associated with the SLAs in that queue q.
Similarly, the energy value of each agent a can be calculated. The energy of each agent a, E(a), is the sum of all energies of the queues on which the agent a can answer calls. In this manner, the importance of each agent can be determined. The higher the energy of the agent, the more important that agent is within the call center.
The SLO method of the present invention receives one of three types of API events from the ACD: an agent is free, a new call event has arrived in the ACD, or a call event previously placed in a queue has exceeded a predetermined time limit. In response to these API events, the SLO method replies in one of four ways: assign an agent to a given call on a queue, assign the call to a given free agent, place the new call event in a queue, or place the new call event on hold. To place the new call event on hold, the new call is placed in a queue and a wake-up time is associated to it.
When a new call event is received by the ACD, the ACD first determines the type of call event and its priority level. For example, the call event is a telephone call and the caller is a VIP customer. Preferably, the priority level is determined by identifying the originator of the call event. Such identification can be made using any type of conventional identification technique. Based on the call type and the priority level, the call event is assigned an appropriate queue. As calls are processed by the ACD, the energy values for each SLA s, E(s), each queue q, E(q), and each agent a, E(a) are dynamically calculated to be current at any given time. Calls are routed based on the calculated current energy values.
FIG. 3 illustrates a method of handling a newly received call event according to the preferred embodiment of the present invention. The preferred method starts at step 10 . At step 15 , a new call event is received by an ACD. At step 20 , the new call is associated to a queue based on the type of call, such as telephone call or email, and the priority of the call. Once the call is associated to the particular queue, a list of the agents associated to the queue is sorted by increasing order of energy at step 25 . In other words, the agent with the least amount of energy is positioned at the top of the list. At step 30 , it is determined if there is a free agent associated with the queue. The free agent is one of the agents from the sorted list in step 25 . If it is determined that there are one or more free agents at step 30 , then at step 35 , the new call event is assigned to the free agent with the lowest energy level. If it is determined at step 30 that there are not any free agents, then at step 40 , the new call event is placed in the queue. After step 35 or step 40 , the method ends at step 45 .
Alternatively, instead of placing the new call event in the queue at step 40 , the new call event can be placed on hold. To place a call on hold, a hold-time is associated to the call and the call is placed in a hold queue. Preferably, the hold time is the skillDelay of the queue, where the skillDelay is the time after which the skill level matching is lifted for a call placed on queue q. After the hold-time expires, the call in the hold queue is “awakened” and it is determined if there is a free agent to receive the call, as in step 30 . If it is determined that there is one or more free agents, then the call is assigned to the free agent with the lowest energy level. If it is determined that there are no free agents, then the call can be placed back on hold, or the call can be placed in the queue, as in step 40 .
FIG. 4 illustrates a method of assigning a newly freed agent to a call according to the preferred embodiment of the present invention. The preferred method starts at step 100 . At step 105 , an agent becomes available to accept a call. To determine which call the agent is to service, a list of queues associated with the agent is sorted in decreasing order of energy at step 110 . Recall that each agent is assigned to one or more queues based on their individual skill levels. At step 115 , the first non-empty queue on the sorted list is selected. In other words, the queue with the highest energy is selected. At step 120 , the agent is assigned to the first call in the selected queue. Alternatively, if call priority is taken into account, the agent can be assigned to a call within the selected queue that minimizes a combination of delay and priority weight. At step 125 , the method ends.
It is understood that the energy levels can be calculated such that the lower the energy level, the worse the performance of the call center. In this alternative case, the embodiments of the SLO method described herein would still prioritize based on worst to best as described above, but the worst case is now the lowest energy level.
The present invention has been described in terms of specific embodiments incorporating details to facilitate the understanding of the principles of construction and operation of the invention. As such, references herein to specific embodiments and details thereof are not intended to limit the scope of the claims appended hereto. It will be apparent to those skilled in the art that modifications can be made in the embodiment chosen for illustration without departing from the spirit and scope of the invention.
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A method including determining a current rate of satisfying a service level agreement constraint, wherein the service level agreement constraint is associated to selected ones of each incoming contact within a contact center, comparing the current rate to a target rate associated with the service level agreement constraint to calculate a satisfaction value, measuring a size of a queue associated with the service level agreement constraint, and calculating a potential value associated with the service level agreement constraint based on the satisfaction value, the queue size and a weighted priority level associated with the service level agreement constraint.
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STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
The development of this invention was partially funded by the Government under grant DE-FG05-87ER60503 awarded by the Department of Energy. The Government may have certain rights in this invention.
BACKGROUND OF THE INVENTION
This invention pertains to laser optogalvanic signals in plasma, particularly to the separation of two different components comprising such signals: photoacoustic mediated effects, and ionization rate change effects.
Plasmas are used extensively in a number of industrial or manufacturing processes, such as depositing diamond films, depositing other thin films, semiconductor manufacture, plasma etching, and deposition of coatings for a variety of purposes. Because of its complexity, plasma characteristics are incompletely known. The mechanisms of depositions, etchings, coatings, etc. are not well understood.
Plasmas generated at high rf frequencies (more than a few MHz) are generally better suited in applications in etching and deposition. However, there are serious problems in analyzing or measuring such high rf plasmas. Consequently, such plasma manufacturing processes are currently used with incomplete knowledge of important plasma characteristics, such as electron and ion temperatures, plasma potential, and the nature of the ions interacting with the surface of the substrate material. This incomplete knowledge precludes proper understanding of etching and deposition processes. Therefore, plasma etching and deposition processes are currently used in a somewhat hit-or-miss manner with different gases, gas mixtures, rf frequencies, and powers.
The laser optogalvanic (LOG) effect is the change of the electrical impedance of a plasma caused by resonant absorption of laser radiation in the plasma. The absorption of laser radiation by a plasma species disturbs the dynamic equilibrium of the various plasma processes (e.g., absorption/emission, collisional excitation/deexcitation, ionization/recombination, etc.), and thus produces a LOG signal.
The laser optogalvanic effect has been used for some time to study rf discharges in plasma. Better understanding of plasma characteristics should enhance the quality or rate of plasma manufacturing processes. Because present optogalvanic methods do not extract the "true" optogalvanic signal (i.e., the ionization rate change component), they are of limited analytical use.
In our recent work on the LOG effect in rf discharges in iodine, it was found that LOG signals were generated by two distinct mechanisms: (i) equilibrium ionization rate changes (IRC); and (ii) a photoacoustic (PA) effect. Kumar et al., "Time-Resolved Laser Optogalvanic Spectroscopy of Iodine in a Radio Frequency Discharge," J. Chem. Phys., Vol. 90 (8), pp. 4008-4014 (1989). It was shown that thermal effects and ionization rate changes are not involved in the final step of PA-mediated LOG signal generation. Instead, it was found that the pressure wave generated by a PA effect produced the LOG signals by an actual physical movement of the charged species in the "sensitive" region of the discharge. Iodide ions have very small mobility compared to electrons, and at an rf frequency of ˜30 MHz, the ions oscillate about their mean positions with a small displacement amplitude. In iodine, for low power discharge, the sensitive regions are therefore confined to the vicinity of the rf electrodes. This region can be identified as positive-ion sheaths that are perturbed by the PA wave. These PA-mediated LOG signal components were easily identified by the acoustic wave transit time delay from the region of laser excitation to the rf electrode(s). Laser-induced direct photoionization or collision-assisted photoionization, on the other hand, generated a nearly synchronous change in discharge conductivity and, consequently, a fast LOG signal component. The fast and the slow LOG signal components in iodine, being separated in time, were distinguished and identified. This reference does not, however, disclose or suggest means for resolving the IRC and PAM components when those two components overlap in time. (For simplicity, we will use the abbreviation IRC to refer to LOG signals, or components of LOG signals, generated by ionization rate changes, and PAM to refer to photoacoustically mediated LOG signals or components.)
In general, the PAM and IRC components of a LOG signal overlap in time, and a complex signal profile results. For example, neon atoms are much lighter than iodine, and the "sensitive" region can be spatially diffuse. A laser beam, therefore, propagates through the "sensitive" region of the discharge, and a complex LOG signal profile results.
To the knowledge of the inventors, no prior reference discloses or suggests a means for resolving IRC and PAM components of a LOG signal where those signal components overlap in time. Such overlap can be caused, for example, when the sensitive region is diffused throughout the discharge.
Haner et al., "Time-Resolved Study of the Laser Optogalvanic Effect in I 2 ," Chem. Phys. Lett., Vol. 96 (3), pp. 302-306 (1983) discloses that a photoacoustic effect can be a component of a laser optogalvanic signal.
Uetani et al., "Temporal Variation of Electron Density in a Laser-Perturbed Discharge Plasma and its Relationship to the Optogalvanic Signal," Optics Comm., Vol. 49 (4), pp. 258-262 (1984) discloses that the resonance frequency of a plasma in an rf-discharge may be shifted by laser irradiation.
SUMMARY OF THE INVENTION
We have discovered a new technique that allows separation of LOG signals into their IRC and PAM components, even when both types of signal components overlap in time. Dramatic changes occur in the temporal profiles of LOG signals produced by pulsed laser excitation as the rf frequency is varied near the electrical resonance peak of the plasma with the associated driving/detecting circuits. Observation of these changes permits separation of the IRC and PAM components.
This novel technique allows a better understanding of radiofrequency plasmas, particularly in the "sheath" region of the plasma near the electrodes, a region which plays a critical role in etching and deposition processes. This better understandings should, in turn, permit the manufacture of better finished products.
The novel technique may also be used to construct novel instruments to study radiofrequency discharges in plasmas. By resolving the IRC and PAM components of a LOG signal, it is now possible to build a spectrometer which can yield "true" optogalvanic spectra--i.e., spectra resolved into IRC and PAM components. Such a spectrometer should be useful in chemical analysis of rf plasmas.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates the experimental setup for laser optogalvanic (LOG) study of a radiofrequency discharge plasma.
FIGS. 2A-H illustrate temporal evolution of LOG signals in an rf discharge in neon, at or on either side of the rf resonance frequency.
FIG. 3 illustrates the rf resonance profile of the plasma and the associated driving/detecting circuit.
FIGS. 4A-C illustrate averaged time-resolved LOG signals in an rf discharge in neon, at or on either side of the rf resonance frequency.
FIG. 5 illustrates the difference of the temporal profiles of FIGS. 4B and 4A.
FIG. 6 illustrates the difference of the temporal profiles of FIGS. 4C and 4A.
DETAILED DESCRIPTION OF THE INVENTION
The experimental apparatus for LOG measurements was substantially as described in Kumar et al., "Time-Resolved Laser Optogalvanic Spectroscopy of Iodine in a Radio Frequency Discharge," J. Chem. Phys., Vol. 90 (8), pp. 4008-4014 (1989); and Kumar et al., "Photoacoustics using Radio-Frequency Laser-Optogalvanic Detection: A New Technique for Low Pressure Photoacoustic Spectroscopy," Can. J. Phys., Vol. 64, pp. 1107-1110 (1986); the entire disclosures of both of which are incorporated by reference.
As illustrated in FIG. 1, the sample was contained in quartz discharge cell 2, two cm in diameter and thirty cm long. Two copper electrodes 4 and 6, each wound around the exterior of cell 2, were positioned about 5 cm apart. An rf oscillator 8 and amplifier 10 served as a ˜30 MHz source of rf power. The rf voltage was resonantly stepped-up and applied to external electrodes 4 and 6. An rf power of 0.1-0.2 W was sufficient to sustain a stable, low-noise discharge in neon at ˜5 torr pressure.
Resonantly tuned pick-up coil 12, also wound around discharge cell 2, was situated ˜1 cm below the lower rf electrode 6 and coupled to the rf discharge, which extended beyond electrodes 4 and 6. The output of pulsed, tunable dye laser 14 impinged transversely on cell 2 at a point between electrode 6 and pick-up coil 12. When laser 14 was tuned to a frequency absorbed by a species in the discharge, a change occurred in the rf power transferred to pick-up coil 12. This change constituted the optogalvanic signal. This signal was recovered by demodulation in signal-recovery section 16, and after amplification by amplifier 18, was sent to oscilloscope or box-car 20 for visual monitoring or for recording. It is also possible to eliminate pickup coil 12, and use the rf circuit itself as its own detector.
A convenient alternative to this sample cell was found to be a commercially available hollow cathode lamp with a long neck (˜6 cm) filled with neon (˜5 torr). (Beckman Instruments, Part No. 180181). The internal electrodes, being relatively far from the rf electrodes and from the pick-up coil placed around the neck, did not substantially interfere with the rf discharge. In this case, the distance between electrodes 4 and 6 was reduced to ˜2 cm. Most measurements described below used such a commercially available hollow cathode lamp.
The rf circuit was initially tuned as follows: With the discharge on, at a given power amplifier gain, the oscillator frequency and tuning capacitor 22 associated with the primary of the step-up transformer were adjusted to find the maximum rf power meter "dip." This dip indicated resonance in the driving circuit. Tuning capacitor 24 associated with pick-up coil 12 was then adjusted for maximum "pick-up," as indicated by a rectified DC maximum. Even though pick-up coil 12 put a negligible load on the rf discharge, it is then preferred to recheck the resonance in the driving circuit. Indeed, because the driving circuit resonance was slightly dependent on the rf power, it should finally be fine-tuned when the discharge attains stability. The resonance frequency is denoted f o .
A flash-lamp pumped dye laser (Chromatix CMX-4, ˜1 μs pulse width, resolution ˜0.1 cm -1 , beam focused to <0.5 mm diameter) was used to excite various 1s j →2p k transitions in the neon. The resulting LOG signal profiles were recorded with the rf frequency f: (1) set at f o , (2) set slightly below f o , and (3) set slightly above f o . Changes in LOG signal profile were also monitored as the rf frequency was scanned across the driving circuit resonance peak. Finally, with the laser off, the rf resonance profile was recorded by scanning f, and recording the DC voltage in the demodulator of the signal-recovery section.
LOG signals from several 1s j →2p k neon transitions were studied in the excitation range 15,000-17,000 cm -1 . The temporal profiles of the faster components of these signals were extremely sensitive to changes in rf frequency near f=f o . While the temporal profiles of the LOG signals from different neon transitions may differ because of their dependence upon 1s j population densities, from which the excitation occurs, and upon the decay branching ratios of the terminal 2p k levels, their overall shapes varied in systematic fashion with rf frequency. These changes fell into a pattern illustrated in FIGS. 2A-H for the transition 1s 5 →2p 2 (16,996.61 cm -1 ). FIGS. 2A-H illustrate the temporal evolution of LOG signals in an rf discharge in ˜5 torr neon, with the rf frequency set at, or on either side of, the resonance frequency f o =29.24 MHz. Only the 1s 5 →2p 2 transition is shown in FIGS. 2A-H. (Similar effects were observed for other 1s j →2p k transitions). In FIGS. 2A and 2B, f=f o =29.24 MHz. In FIGS. 2C and 2D, f=29.04 MHz. In FIGS. 2E and 2F, f=29.44 MHz. In FIGS. 2G and 2H, f=29.29 MHz. In FIGS. 2A through 2G, laser power was low (<1kW), and nearly equal in all cases. In FIG. 2H, the laser power was ˜2kW. In all cases, peak #1 was synchronous with the laser pulse to within ˜0.5 μs.
The following points were noted:
(1) At resonance (29.24 MHz, FIG. 2A and B), the LOG signal consisted of a sharp positive peak at ˜3 μs (peak #2), followed by a slowly varying negative component at ˜30 μs (peak #4), and a much slower positive component at ˜150 μs (peak #5).
(2) At a frequency slightly below resonance (29.04 MHz, FIG. 2C and D), the LOG signal consisted of an additional sharp, although weak, negative peak (#1) synchronous with the laser pulse, followed by a much stronger (as compared to peak #2 in FIG. 2A) and somewhat broadened (optical or amplifier saturation) positive signal at ˜2 μs (peak #3). This strong peak appeared to have swamped the original positive peak #2 in item (1) above. (See also item (5) below.) The initial, negative part of the slowly varying component (peak #4, now at ˜50 μs) was somewhat stronger, and the final, positive component (peak #5) was broader and weaker than the same components of FIG. 2A.
(3) At a frequency slightly above resonance (29.44 MHz, FIG. 2E and F), the LOG signal consisted of the weak peak #1, now positive, followed by the strong peak #3, now negative. This strong negative peak appeared to have swamped the positive peak #2 in item (1) above. (See also item (5) below.) The peak #4 (of FIG. 2A) appeared to be neutralized by the positive overshoot of the strong negative peak #3 (see FIG. 2E). Peak #5 gained some intensity, and its maximum shifted slightly to the left (shorter times). The signal was noisy, to an extent that it increased the "start point" of the trace in FIG. 2F by almost half a division. All peaks were, however, reproducible. Note that the overall signal-to-noise ratio for the slowly varying components decreased as the rf frequency moved away from f o .
(4) When the rf frequency was 29.29 MHz (FIG. 2G), peak #'s 1, 2, and 3 were not observed. Peak #4's maximum was shifted slightly to the right. However, when the laser power was increased at the same rf frequency, a sharp, fast, negative peak reappeared (FIG. 2H). The nature of this peak will be discussed below.
(5) When the rf frequency step change was smaller than that of (1)-(4) above, a gradual change of the LOG signal pattern occurred. As f decreased below f o (29.24 MHz), a weak, sharp, negative peak (#1) synchronous with the laser pulse appeared, and grew slowly (FIG. 2D). Simultaneously, a positive peak #3 (unresolved from peak #2) appeared and grew rapidly on the right-hand shoulder of peak #2. This peak rapidly strengthened and engulfed peak #2, and eventually saturated the system (optical or amplifier) to produce a fairly broad, saturated peak at ˜8 μs (FIG. 2D). Thus three peaks occurred in the LOG signal within ˜10 μs of laser firing. On the other hand, as f gradually increased above f o , a weak positive (unresolved) peak (#1) grew slowly on the left shoulder of the peak #2 (FIG. 2F); and a strong negative peak appeared and grew rapidly on the right shoulder of the same peak (#2). As f increased further, this strong negative peak engulfed the positive peak (#2), and the resulting 29.44 MHz pattern, as shown in FIG. 2F, was obtained.
(6) The delayed, broad, positive peak at ˜150 μs was not inverted at any setting in (1)-(4) above. Except for FIG. 2E, a similar statement applies to the broad, negative peak at ˜30 μs. In FIG. 2E, it appears that the negative nature of the peak was partly overwhelmed by the positive overshoot of the strong negative peak #3.
(7) Similar behavior was observed with the LOG signals of other 1s j →2p k neon excitations. However, if the metastable states 1s 5 and 1s 3 were not involved in the laser excitation process (either as an initial level, or as a final level after relaxation from the upper 2p k level), the ˜30 and ˜150 μs components of the LOG signals were either nonexistent or extremely weak. In particular, the slowest component (i.e., the peak at ˜150 μs), was never present in such excitations.
(8) For some excitations (e.g., 1s 2 →2p 2 at 15,149.7 cm -1 ), the LOG shape seemed to invert relative to the 1s 5 →2p 2 signal (for the same experimental setting). In such cases, inversion of the same pair of LOG signal components occurred as the rf frequency changed from slightly below to slightly above f o .
(9) A slight negative displacement (10-15 μs) of peak #5 (cf. FIG. 2A) occurred as the laser beam was displaced downward along the axis of FIG. 1 (i.e., away from electrode 6). Peak #4 also suffered a displacement of 5-10 μs. No noticeable shift of the position of peak #2 could be detected.
(10) As the rf power increased above 1 W, peaks #4 and #5 (cf. FIG. 2A) became very weak, but their null response toward a change of rf frequency remained the same as described in item (6) above. An exact nulling at f o of the frequency dependent components was then difficult, if not impossible to achieve.
The rf resonance profile of the plasma and associated driving/detecting circuit is illustrated in FIG. 3 as the solid curve. With the laser off, the rf frequency (at constant amplitude) was varied by small steps, and the corresponding response was measured by the rf carrier level, as detected in the pick-up circuit. The LOG signal, of course, was generated not by changing the rf frequency, but by laser excitation of the discharge plasma. The laser excitation, however, altered the plasma resonance characteristics. For small perturbations, the effects on LOG signal generation can be approximated by a shift of the response function of FIG. 3. For discussion purposes, three points P, Q (peak), and R are marked on the resonance profile. An increase in the equilibrium ionization rate resulting from laser excitation produced a leftward shift in the response curve, illustrated in FIG. 3 by the dotted curve. As illustrated by the corresponding arrows, this shift in the response curve caused a positive IRC signal at P, and a negative IRC signal at R. At Q, the resonance peak, the IRC signal was zero or nearly zero, because of the zero slope of the response curve at that point.
Two distinct mechanisms are involved in the generation of LOG signals. This conclusion follows from the fact that one set of peaks in the LOG temporal profile did not alter characteristics as the rf excitation frequency changed from slightly below to slightly above f o , whereas another set of peaks vanished and changed polarity as the rf frequency passed through f o .
We propose a simple phenomenological model for the nature of, and the observed rf frequency-dependent behavior of, the LOG signal. This model is based on two statements: (a) laser excitation of a particular transition, such as a particular 1s j →2p k transition, in the plasma alters the equilibrium ionization rates, with concomitant changes of the resonance characteristics (effective conductivity, capacity, and inductance); and (b) part of the energy absorbed from the laser pulse is released nonradiatively into the translational modes, and this release launches a pressure wave, or photoacoustic effect (PA effect).
On the basis of this model, one set of peaks--those that do not alter characteristics with rf frequency--are mediated by the PA effect (PAM component), whereas another set of peaks, those that are strongly rf frequency dependent, are generated by ionization rate changes (IRC component). This latter set constitutes the true LOG signal, at least in the strict sense of the word "optogalvanic." Thus at f=f o , at low-to-moderate laser powers, only the PAM component is generated. At f≠f o , both mechanisms are active, and the observed LOG profile is a composite of the two signals. Because the IRC component can range from much stronger to much weaker than the PAM component, quite different signal profiles can occur in the same system under different conditions.
A. The PA-Mediated (PAM) LOG Signal
The PAM LOG signals are generated by the actual physical movement of the charged species under the influence of the PA wave. No thermal or ionization rate changes are involved in the final production step of the PAM LOG signal. Because these LOG signal components are inverted when the direction of the PA wave is reversed--reversals that could not be obtained if either thermal or ionization rate changes were involved as a final production step--it follows that such rate changes are not pertinent to these LOG components. When the rf power is increased to a few watts, the sensitive region loses definition, and very complex PAM signals may occur.
It appears that even at ˜0.5 W rf power, the sensitive region (i.e., the positive ion sheath) is not confined to the close vicinity of the rf electrodes. Thus the laser pulse, in the case of neon, impinges on and excites the sensitive region of the Ne discharge. The initial PAM signal should thus not be much delayed. The initial PAM signal should, however, be followed by a slower, damped "ringing." The observed shape of these signals is discussed below. Because PAM signals are induced by the physical movement of charged species, little or no shape change is expected as the rf frequency is varied slightly about f o . Some small amplitude reduction, however, should occur because the response function diminishes as f moves away from f o . Because all peaks in the LOG temporal profile at f=f o (FIG. 2A) meet the above criteria, they all may be assigned to a PAM effect.
The low power rf discharge in the prior reported study of iodine, Kumar et al., "Time-Resolved Laser Optogalvanic Spectroscopy of Iodine in a Radio Frequency Discharge," J. Chem. Phys., Vol. 90 (8), pp. 4008-4014 (1989), had the advantage that the sensitive region of the discharge was confined to the vicinity of the electrodes. Because the point of laser excitation could be removed from the sensitive region, one could decipher the PAM signal by its transit time delay. At the same time, this simplicity previously prevented recognition of the powerful role that is played by the PA effect when the laser beam impinges on the sensitive region of the discharge. Both IRC and PAM effects may be involved in this case, and a LOG signal with a complex envelope may be produced. This situation appears to be the case, for example, with neon, as discussed above.
B. The Temporal Profile of the LOG signal
We now consider the time scales of the two processes and the types of relaxation shapes that may be expected.
(1) For a suitably designed system, the rise time of the LOG signal attributable to direct photoionization will be controlled by the rise time of the laser pulse. The decay time will depend on recombination/collision/diffusion rates, or on the decay time of the laser pulse, whichever is longer. Even in the case of collisional photoionization, because electron-atom/molecule collision rates are on the order of GHz or faster, the LOG signal should be synchronous with the laser pulse, and should exhibit sharp rise and fall times.
(2) If the population of a metastable level is perturbed by laser excitation, a long-lived (0.1-0.5 ms) response may be generated. Metastable levels are equilibrated primarily by collisions, and usually have long decay times. Because metastable levels play dominant roles in the maintenance of the discharge, any perturbation of their population density should produce a strong LOG signal.
(3) The laser excitation process may also release some energy in the PA channel, and a corresponding "delayed" LOG signal may be produced. If excitation occurs in the sensitive region, this delay may be of the order of a few μs or less, depending upon gas pressure, kinetics, etc. Because acoustic signals typically have "ringing" characteristics, the leading edge of a PA-mediated signal should generally comprise a sharp, shockwave transient, followed by one or more damped overshoots.
Inspection of the signal shape in FIG. 2A indicates that the initial positive pulse was delayed a few microseconds relative to the laser pulse, and was followed by a poorly defined ringing pattern. Once perturbed by the laser pulse, which produced population density changes and initiated the PA-mediated shock wave, the recovery of discharge equilibrium involved a multitude of distinct and interrelated processes. The important factors are the kinetics of the equilibration process for various levels; the interaction between the PA wave and the excited levels; the shape and size of the discharge; and the characteristics of the electrical driving circuit. All levels with a perturbed population attain equilibrium by photon emission/absorption or collisional relaxation. To a lesser or greater extent, then, all nonequilibrated levels should contribute to the PA channel. It is therefore possible that the PA ringing component could either grow or diminish after the initial sharp PAM spike, depending on the characteristics of a given system.
The characteristics of the electrical driving circuit may also play a role in shaping the LOG signal. For example, the external ballast resistance in a DC discharge not only controls the stimulus that returns the discharge to equilibrium, but it may also affect some of the other equilibrative processes.
With the above factors in mind, and recognizing that all peaks in FIG. 2A are well-behaved with respect to a variation of f around f o (i.e., do not undergo drastic changes), we can assign the entire signal in FIG. 2A to a PA effect. Support for this attribution is provided by the temporal behavior of peaks #4 and #5 in FIG. 2A, which shifted slightly as the position of laser excitation was moved along the length of the cell. These shifts can be explained in terms of a propagation delay and/or change in the acoustic resonance pattern relative to the sensitive region of the discharge.
C. The RF Frequency-Dependent LOG Signal
We now show that the rf frequency-dependent components of LOG signals originate in changes of the equilibrium ionization rates caused by the laser excitation. The interpretation of the distinctive behavior of these components as f varies about f o is not trivial. However, because inversion crossover (i.e., nulling) occurs at f o , a useful model is one with an rf/plasma resonance curve as a response/transfer function.
Any change of the equilibrium ionization rates in a discharge plasma results in concomitant changes of conductivity, capacitance, and inductance. Thus laser excitation will momentarily change the plasma resonance characteristics. For example, if the effective capacitance or inductance of the plasma increases, the resonance frequency of plasma and driving/detecting circuits should decrease. This decrease may be represented by a leftward displacement of the response curve (i.e., the dotted curve) of FIG. 3. LOG signal generation by laser-induced changes of the equilibrium ionization rates can be visualized as follows:
(1) The rf frequency values are set, say at points P, Q, or R of FIG. 3.
(2) Laser-induced changes of the equilibrium ionization rate displaces, say leftwards as illustrated, the whole resonance/response curve of FIG. 3. The amplitude of the response curve may be assumed to be invariant because there would not otherwise be a nulling at f=f o .
(3) If the rf frequency is set at P, a small displacement of the resonance curve to the left will increase the response as P moves up the curve, and a positive LOG signal will result.
(4) If the rf frequency is set at R, a small displacement of the resonance curve to the left will decrease the response as R moves down the curve, and a negative LOG signal will result.
(5) If the rf frequency is set at Q (i.e., on resonance at f=f o ) a small displacement of the resonance curve to the left or right will not produce a significant response change, and no LOG signal will result. Thus, even though the equilibrium ionization rate changes, no LOG signal will be generated. This situation is expected only for low laser powers (i.e., for small displacements). As laser power increases, the displacement of the resonance curve may be large enough to decrease the response at f=f o , and hence to produce a negative LOG signal.
(6) If the rf frequency is set at P, and if the laser excitation activates two processes which simultaneously increase and decrease the ionization rates, then these processes will generate LOG signals of opposite polarity. The process that shifts the resonance curve to the left will generate a positive LOG signal, and that which shifts the resonance curve to the right will generate a negative LOG signal. If sufficiently separated in time, two distinct signals may occur. Complementary results follow if the rf frequency is set at R.
(7) For higher power laser excitation, additional features may be observed when f≠f o . For example, if the rf frequency is set at P, a large leftward shift of the response curve may cause f to move past Q and down the right-hand side of the peak. Thus, as the laser power is gradually increased, a positive LOG signal develops, decreases, nulls, and turns negative. However, if the equilibrium ionization rate increases at a slower rate than the detection-time resolution, the corresponding LOG signal will show an initial positive component which, at its trailing edge, is followed by a negative component. Such behavior was observed in neon.
(8) Background noise is lowest at f=f o , and increases on either side of f o . However, the maximum of the LOG signal generated by a displacement of the response curve will occur at that point on the curve which has maximum slope. Thus the best signal-to-noise ratio for IRC components will occur at rf frequencies somewhere between f o and the point of maximum slope.
(9) If the laser excitation results in an increase in the equilibrium ionization rate, a positive IRC component is generated at P, implying that the response curve shifts to the left.
This simple model explains the behavior of the IRC component, whether induced by a change of the rf frequency or of laser power.
The origin of the two distinct rf frequency-dependent LOG signal components (i.e. two distinct changes of the equilibrium ionization rates corresponding to peaks #1 and #3) needs further elaboration. The polarities of peaks #1 and #3 indicate an initial rapid decrease of equilibrium ionization rates, followed by a slightly delayed increase of ionization rates. The mechanisms underlying those changes will now be discussed.
Laser excitation of the 1s 5 →2p 2 transition in neon is followed by a relaxation of the excess population in the 2p 2 level to all four 1s j levels. The radiative transition probabilities (A) of the 2p 2 level to levels 1s 2 , 1s 3 , 1s 4 , and 1s 5 have been previously reported to be 2.32, 1.46, 0.561, and 1.15×10 7 s -1 , respectively. The 1s 3 and 1s 5 levels are metastable, and consequently any laser-induced population change which they suffer can equilibrate only through collisional effects. However, the decays of the 1s 2 and 1s 4 levels to the ground state are allowed (A=66.4×10 7 s -1 ) and partially allowed (A=4.76×10 7 s -1 ), respectively.
Consequently, the sequence of events after laser excitation was inferred to be as follows:
(1) The 1s 5 →2p 2 laser excitation depleted the 1s 5 metastable level population, which in turn produced an immediate decrease in the equilibrium ionization rates. At the neon pressures and the rf powers used here, Penning ionizations of the metastable levels dominated the electron impact ionization of the upper 2p 2 level, and the equilibrium ionization rate dropped.
(2) The excited 2p 2 population, prior to relaxation to the lower 1s j levels, dissipated some energy via collisions, and initiated the events that generated the first peak of the PAM component (peak #2) and, by overshot, the somewhat broader #4 peak component. The relaxation of the 2p 2 level was complete within a fraction of a microsecond.
(3) The vacuum ultraviolet (VUV) fluorescence from the 1s 2 and 1s 4 resonant levels, which acquired excess population by relaxation of the 2p 2 level, was radiatively trapped. The effective fluorescence lifetimes of the 1s 2 and 1s 4 levels under these conditions are known to be <1 μs and <11 μs, respectively. The resultant VUV photons photoionized some excited entities in the discharge, and hence increased the ionization rate. Since the effective lifetime of the 1s 2 level is less than the laser pulse width, its effects were merely superimposed on the initial set of events. A short radiation-trapped lifetime for the 1s 2 fluorescence implies a fast escape of photons and a negligible, or very small, contribution to ionization rate changes. The 1s 4 level, on the other hand, has a much longer effective fluorescence lifetime, and hence it contributed significantly--at least at later times--to an increase of equilibrium ionization rates (peak #3). The delay of peak #3 relative to the laser pulse (˜8 μs) is consistent with the 1s 4 effective lifetime.
The rapid decay of peak #1 is largely attributable to swamping by peak #3, which was overwhelmingly strong and of opposite polarity.
FIG. 2G, in which an rf setting of 29.29 MHz seemed to eliminate the initial part of the PA-mediated signal, requires some comment. Because 29.29 MHz lies just above f o , the first rf dependent component synchronous with the laser pulse was weak and not observed, whereas the second rf dependent component (which was negative for f<f o ) nearly neutralized the initial positive peak #2 of the PAM component. Slight mismatches, if any, at particular instants were buried in the noise. As the laser power increased, a larger displacement of the response curve did produce a distinct negative signal (FIG. 2H). An increase in slope of the response curve at f(≃f o ) as Q moved away from f (due to increased ionization) resulted in a larger negative IRC component, one which more than compensated for the corresponding positive PAM peak #2.
To summarize, the various peaks in FIG. 2 can be assigned as follows: (i) Peak #'s 2, 4, and 5 in FIG. 2A and B (f=f o ) were pure PAM components; (ii) Peak #'s 1 and 3 were of IRC origin; (iii) Peak #'s 2, 4, and 5 in FIG. 2C-H (f≠f o ) were admixtures of both PAM and IRC components. Peak #5 was predominantly PAM in nature. Peak #4 may have had some IRC component (except when the magnitudes were controlled by overshoot of strong peak #3).
A preferred manner of separating the PAM and IRC components is to digitize several temporal profiles, and then to average those profiles. FIGS. 4A-C, for example, illustrate low-noise, averaged temporal profiles (of 100 traces each) for the same transition in neon (1s 5 →2p 2 ), as recorded by a digital oscilloscope (LeCroy Model 9400). FIG. 4A illustrates the averaged LOG signal at the rf resonance frequency (29.37 MHz, slightly different from that in FIGS. 2A and 2B because a slightly different rf power was used.) FIGS. 4B and 4C illustrate the corresponding LOG signals at f=29.17 MHz and f=29.57 MHz, respectively.
FIG. 4A, recorded at rf resonance peak, was attributed solely to the PAM component. The IRC components were obtained by subtracting the temporal profile of FIG. 4A from that of either FIG. 4B or FIG. 4C. These differences, respectively, are illustrated in FIGS. 5 and 6. (Note that the vertical axis in FIGS. 5 and 6 is expanded relative to that of FIGS. 4A-C.) The lack of precise symmetry (peak heights) between the profiles of FIGS. 5 and 6 indicates that the response curve (analogous to that of FIG. 3) has slopes of different magnitude at points analogous to P and R. Closer symmetry would probably result by moving the points P and R closer to Q--i.e., taking the off-resonance measurements closer to the rf resonance peak.
Laser-induced changes in the equilibrium ionization rate can be estimated from the slope of the response curve at any actual operating point (such as P or R), by calibrating the shift in the response with a known (or otherwise measured) change in the ionization rate.
Although it is preferred to make measurements in accordance with this invention at the resonance frequency peak, and to compare those measurements to measurements taken at one or more other frequencies near the resonance peak, other modes of practicing this invention are possible. For example, LOG measurements could be made at two or more frequencies near (but not at) the peak, followed by an extraction of that component which varies slowly with a change in radiofrequency, and the component which varies rapidly. The former is a measure of the PAM component, and the latter, a measure of the IRC component.
Another alternative is to take a LOG measurement at low laser power at the resonance peak only, which measurement should comprise a PAM component only.
It is preferred to take multiple LOG measurements at each frequency, and to average those measurements to improve signal-to-noise ratios, as illustrated in FIGS. 4A-C.
A frequency "near" or "close to" the resonance frequency is one sufficiently close to the resonance frequency maximum to permit meaningful measurements of PAM and IRC components in accordance with this invention.
Although the use of a true pulsed laser is preferred for its better time resolution, the present invention should also work with a chopped cw laser. Therefore, references in the claims to a "pulsed laser" should be understood also to include a chopped cw laser; and reference in the claims to a "pulse" of a laser should be understood also to include a segment from a chopped cw laser beam.
The observed experimental results presented here for neon are generally similar to those which have also been observed in experiments with argon.
The entire disclosure of Kumar et al., "Role of Photoacoustics in Optogalvanics," J. Chem. Phys. Vol. 93 (6), pp. 3899-3905 (1990) (which is not prior art), is incorporated by reference.
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Separation of laser optogalvanic signals in plasma into two components: (1) an ionization rate change component, and (2) a photoacoustic mediated component. This separation of components may be performed even when the two components overlap in time, by measuring time-resolved laser optogalvanic signals in an rf discharge plasma as the rf frequency is varied near the electrical resonance peak of the plasma and associated driving/detecting circuits. A novel spectrometer may be constructed to make these measurements. Such a spectrometer would be useful in better understanding and controlling such processes as plasma etching and plasma deposition.
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CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a National Stage (§371) of International Application No. PCT/US2013/046266, filed Jun. 18, 2013, which claims priority from U.S. Provisional Application No. 61/661,918, filed Jun. 20, 2012, the disclosures of each of which are hereby incorporated by reference in their entirety.
FIELD OF THE INVENTION
The invention relates to an oilfield closing device, also known as a blowout preventer (BOP) and an electromagnetic actuator for closing the BOP.
BACKGROUND
Considerable safety measures are required when drilling for oil and gas on-shore and off-shore, and one of the key safety measures is the use of blowout preventers. BOPs are basically large valves that close, isolate and seal the wellbore to prevent the discharge of pressurized oil and gas from the well during a kick or other event. One type of BOP used extensively is a ram-type BOP. This type of BOP uses two opposing rams that close by moving together to either close around the pipe or to cut through the pipe and seal the wellbore.
The blowout preventers are typically operated using pressurized hydraulic fluid to control the position of the rams. Most BOPs are coupled to a fluid pump or another source of pressurized hydraulic fluid. In most applications, multiple BOPs are combined to form a BOP stack, and this may include the use of multiple types of BOPs. In some applications, several hundred gallons of pressurized hydraulic fluid may have to be stored at the BOP to be able to operate the BOP.
U.S. Pat. No. 7,338,027 describes a ram-type blowout preventer that is designed to use less fluid to address the problems of storing and pressurizing large quantities of hydraulic fluid. The patent provides an overview of a BOP and the method of its operation.
Conventional hydraulic blowout preventers require a considerable amount of space, mainly due to the hydraulic storage tanks and the associated pressurized accumulators that are used as the driving force for the hydraulic fluid. Further, these systems are heavy and become more difficult to operate and less efficient when used in deepwater subsea conditions because of the hydrostatic pressure of the seawater. In addition, hydraulic blowout preventers can take some time to close depending on the control scheme being used to close the blowout preventer. It is desirable to provide a blowout preventer that does not have these disadvantages.
SUMMARY OF THE INVENTION
This invention provides a blowout preventer comprising: a body comprising a bore therethrough; a cavity disposed through the body and intersecting the bore; first and second closure members moveably disposed within the cavity on opposite sides of the bore; a first rod having a length and comprising a first end coupled to the first closure member; a second rod having a length and comprising a first end coupled to the second closure member; a first glider assembly wherein a second end of the first rod is at least partially disposed within the first glider assembly; and a second glider assembly wherein a second end of the second rod is at least partially disposed within the second glider assembly wherein the first and second rods have magnets along at least a portion of the length of each rod; the first and second glider assemblies are located on opposite sides of the bore; and the first and second glider assemblies each comprise means for generating an electromagnetic field.
The invention further provides a method of sealing a wellbore and stopping the flow of hydrocarbons therethrough comprising: providing a blowout preventer in the wellbore, the blowout preventer comprising: a body comprising a bore therethrough that is aligned with the wellbore; a cavity disposed through the body and intersecting the bore; first and second closure members moveably disposed within the cavity on opposite sides of the bore; a first rod having a length and comprising a first end coupled to the first closure member; a second rod having a length and comprising a first end coupled to the second closure member; a first glider assembly wherein a second end of the first rod is at least partially disposed within the first glider assembly; and a second glider assembly wherein a second end of the second rod is at least partially disposed within the second glider assembly; wherein the first and second rods have magnets along at least a portion of the length of each rod; the first and second glider assemblies are located on opposite sides of the bore; and the first and second glider assemblies each comprise means for generating an electromagnetic field; and generating an electromagnetic field in the first and second glider assemblies that interacts with the magnets located along the first and second rods causing the rods and the closure members attached to the rods to move towards the center of the bore such that the first closure member contacts the second closure member, sealing the bore.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts an embodiment of the blowout preventer with the rams in open position.
FIG. 2 depicts an embodiment of the blowout preventer with the rams in closed position.
FIG. 3 depicts a schematic view of the operation of the system as the blowout preventer is closed.
DETAILED DESCRIPTION
The electromagnetic actuated blowout preventers described herein overcome these disadvantages and provide a more compact, lighter and more efficient blowout preventer. These blowout preventers will be described in more detail with respect to the figures, although it is noted that these figures depict one of many possible embodiments for use of an electromagnetic actuated blowout preventer.
FIG. 1 depicts an embodiment of a blowout preventer according to the invention. The blowout preventer is shown in the open position. The blowout preventer 10 may be connected at the top 12 and bottom 14 to tubular pipe, to the wellbore or to additional blowout preventers to form a BOP stack (not shown). The tubular 16 passes through the blowout preventer bore 18 and may be a drill string, riser for the production of oil and gas from the wellbore or any other tubular used in drilling, completion, workover, production or other steps in producing oil and gas from subterranean formations.
The blowout preventer may be located at or near the seafloor or on a drilling or production vessel located at or near the surface of the sea for subsea wells, or on land for on-shore applications.
The blowout preventer comprises a cavity 20 that is shown here as a horizontal cavity that extends from one side of the blowout preventer to the other side. A first closure member 22 is located to the left of the bore and a second closure member 32 is located to the right of the bore. These closure members are typically referred to as rams, and these can be pipe rams, blind rams, shear rams or blind shear rams. Pipe rams generally have a half circle opening in the edge nearest the bore such that when the pipe rams move toward the tubular 16 , they contact each other and form a seal around the tubular. Pipe rams only restrict flow in the annulus around the tubular, but not flow inside of the tubular. Blind rams have no openings for tubing, and these are used to close off a well when the well does not contain any tubing or pipe. Shear rams generally have a hardened steel blade that is designed to cut through the tubular 16 . Blind shear rams are intended to seal a wellbore even when the bore contains a tubular by cutting through the tubular as the rams close off the well. The electromagnetic actuator can be used with any of these types of closure members.
The first closure member is coupled to the first end 24 of a first rod 26 . The first rod has magnets 28 , preferably permanent magnets, along the length of the rod or at least along a portion of the length of the rod. The second closure member is coupled to the first end 34 of a second rod 36 . The second rod has magnets 38 , preferably permanent magnets, along the length of the rod or at least along a portion of the length of the rod.
The magnets are preferably positioned such that the magnetic fields of the magnets alternate along the length of the rod. For example, a line of magnets may be positioned such that the magnetic field is in one direction and a second line of magnets may be positioned such that the magnetic field is in the opposite direction. One embodiment of this is to use the same type of magnet, but to alternate which side of the magnet faces outward from the rod. The rod may have a cross sectional area that is circular or one of many shapes, including triangular, square, pentagonal, hexagonal, heptagonal, or octagonal. Shapes with flat sides may be easier to construct as the magnets can be attached to a flat surface as opposed to a curved surface.
Each of the rods is situated such that a second end of the rod is at least partially disposed within a glider assembly. The second end 25 of the first rod is disposed at least partially within a first glider assembly 29 . The second end 35 of the second rod is disposed at least partially within a second glider assembly 39 .
The first and second glider assemblies comprise means for generating an electromagnetic field. The electromagnetic field may be generated by coils of wire positioned along the length of the glider assembly. The direction of the electromagnetic field is determined by the direction in which the current flows through the wire. In addition, ferromagnetic or other material can be positioned within the coil to improve the strength of the magnetic field produced by the coil. Alternatively, a system similar to and using the same principles as a rail gun could be used to start movement of the rod. In this embodiment, the second ends 25 , 35 of each of the first and second rods 26 , 36 could be in contact with separate sets of conductive rails 40 . When a large enough current is applied to the rails 40 , the rods 26 , 36 would be forced towards the bore of the BOP.
FIG. 2 depicts the blowout preventer in the closed position. The elements of the system are numbered the same as in FIG. 1 . This figure shows the closure members, in this figure, pipe rams, closed around tubular 16 to seal the annular space of the wellbore surrounding the tubular. The rod is still at least partially disposed within the glider assembly even when the closure members are closed. This allows for the BOP to be opened and to maintain the stability of the rods while the BOP is closed.
The method of operation to close the blowout preventer will be further described with respect to FIG. 3 , which shows a simplified view of the system to illustrate its operation. FIG. 3 shows one permanent magnet 50 , as would be found on the rod with the south pole facing towards a part of the glider assembly 52 . The four stages shown in the figure show how the magnetic field of the glider assembly is changed to accelerate the rod and then decelerate the rod.
Stage 1 shows the acceleration of the rod as the magnet on the rod is attracted to the electromagnet on the glider assembly. In stage 2, the magnet on the rod is attracted to the next electromagnet while being repelled by the electromagnet that it just passed. The current in the respective coils of wire is altered to alter the magnetic field produced. In stage 3, the rod begins to decelerate due to the attractive force of the magnets it just passed along with the repulsive force of the magnets ahead of it. This continues in stage 4 until the magnets (and the rod) come to a stop. This occurs at the point where the first and second closure members have come into contact to seal the wellbore.
Depending on where the magnets are positioned along the rod, current is only applied to the electromagnets that are in the vicinity of the permanent magnets on the rod. If magnets are located along the entire length of the rod then the operation as shown in FIG. 3 will be carried out sequentially for each magnet as it passes the electromagnets on the glider assembly. If magnets are only located along a portion of the length of the rod then the electromagnets will only be powered when the magnets on the rod are nearby.
As the electromagnetic fields are produced the rod will begin to move through the glider assembly and will cause the closure member to close with sufficient force to overcome the wellbore pressure and in the case of shear rams to cut through the pipe and withstand the wellbore pressure. Once the closure member comes into contact with the other closure member, a locking member will engage thus locking the closure members and/or the rods into place to prevent the BOP from opening even if the electrical current to the electromagnets is turned off.
One embodiment of this blowout preventer also comprises a device or system to aid in initiating movement of the shaft. Depending on the design of the system, it may take some time to generate a sufficient electromagnetic field to accelerate the rod. There are many possible methods or devices to help start the system, and then the force to continue to move the rod would be a result of the electromagnetic field and the interaction with the magnets on the rod.
Possible systems for initiating movement of the rod include the use of explosives or propellants. Small explosives or propellants could be placed outside the second end of the rods and when detonated would provide sufficient force to start the rod moving. Pistons could optionally be placed on the ends of the rod to help absorb the force of the explosives or propellants.
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A blowout preventer comprising: a body comprising a bore therethrough; a cavity disposed through the body and intersecting the bore; first and second closure members moveably disposed within the cavity on opposite sides of the bore; a first rod having a length and comprising a first end coupled to the first closure member; a second rod having a length and comprising a first end coupled to the second closure member; a first glider assembly wherein a second end of the first rod is at least partially disposed within the first glider assembly; and a second glider assembly wherein a second end of the second rod is at least partially disposed within the second glider assembly.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates, in general, to cotton ginning and in particular, to a method and an apparatus for restoring moisture to lint cotton in a cotton gin.
2. Information Disclosure Statement
A modern cotton gin includes several coacting subsystems that not only separates cotton seed from lint cotton, but that also dries and cleans the lint cotton and packages the lint cotton into bales for transfer to a cotton warehouse or textile mill, etc. Seed cotton (i.e., raw cotton from the cotton field) usually arrives at the cotton gin in large trailers or modules. Some type of unloading system, such as a large suction pipe or module feed system, conveys the seed cotton from the trailers or modules to the initial stages of the ginning process, typically a moisture balancing stage to either reduce or increase its moisture content to a desired level, and a rough cleaning stage to remove leaves, small trash, sticks, etc., from the seed cotton. The partially processed seed cotton is then transferred to one or more gin stands for “ginning”, i.e. for separation of the cotton seed and fiber. Each gin stand typically includes a roller gin or saw gin, etc. A typical cotton gin may have three or more gin stands. After ginning, the cotton fiber is typically referred to as “lint cotton” (sometimes referred to as “cotton lint” or just “lint”). The ginned lint may then pass through a lint cleaning stage to remove any small trash or dirt remaining in the lint. The cleaned lint is then carried through a lint flue or the like to a battery condenser, where the cleaned lint is formed into a continuous batt and discharged onto a lint slide. The batt is conveyed down the lint slide to a bale press where the batt is compressed and formed into one or more bales. Each bale may then be tied with bailing wire and wrapped with plastic, etc., before being stored or transferred to a warehouse, textile mill, etc.
For many years, cotton ginners have tried various methods to add moisture to lint cotton before the lint enters the bale press. Most of these prior methods add moisture at the lint slide, after the lint has left the battery condenser formed into a batt, and just prior to the batt entering the bale press. However, the accuracy of the resultant moisture level in the finished bale using these prior methods has not been universally acceptable. The typical prior method merely adds the same amount or volume of moisture to the batt, regardless of the rate at which the batt is moving down the slide (e.g., regardless of how many bales a gin stand is producing per hour, etc.), or of the preexisting moisture content of the batt.
A preliminary patentability search in Class 19, subclass 66C, and Class 100, subclass 74, produced the following patents, some of which may be relevant to the present invention: Buzick, U.S. Pat. No. 2,914,809, issued Dec. 1, 1959; Hurdt, U.S. Pat. No. 3,324,513, issued Jun. 13, 1967; Mangialardi et al., U.S. Pat. No. 3,392,424, issued Jul. 16, 1968; Jackson, U.S. Pat. No. 4,103,397, issued Aug. 1, 1978; Vandergriff, U.S. Pat. No. 4,140,503, issued Feb. 20, 1979; Woods, U.S. Pat. No. 4,726,096, issued Feb. 23, 1988; and Vandergriff, U.S. Pat. No. 5,381,587, issued Jan. 17, 1995.
None of known prior art, either singly or in combination, disclose or suggest the present invention.
BRIEF SUMMARY OF THE INVENTION
The present invention includes an apparatus and method for restoring moisture to lint cotton in a cotton gin. The concept of the present invention is to precisely adjust the moisture content of lint cotton at a lint slide based on the final moisture desired in the bale, the volume of lint cotton present (i.e., the ginning rate), and, depending on the model or mode of the present invention, the moisture present in the lint cotton before adding moisture. The present invention applies moisture to the lint cotton on the lint slide prior to entering the press. In the automatic mode of the present invention, the amount of moisture applied is determined by measuring the moisture in the lint cotton as it leaves the battery condenser (preferably using an infrared moisture measuring sensor or the like), subtracting the value of that measured incoming moisture from the desired final moisture of the finished bale, and then multiplying the difference by the rate of ginning in bales per second, resulting in the percent of moisture to be added per second to the lint cotton between the battery condenser and bale press. This data is used by the present invention to deliver a very accurately metered volume of moisture to each bale, resulting in a finished bale with the desired final moisture content, regardless of the incoming moisture or the rate of ginning.
The apparatus of the present invention includes, in general, rate measuring means for measuring the rate of lint cotton exiting a battery condenser; moisture adding means for adding a precise amount of moisture to the lint cotton between the battery condenser and a bale press based on the desired moisture content of the cotton bale, and the rate of lint cotton exiting the battery condenser; and, perhaps, moisture content measuring means for measuring the moisture content of the lint cotton as it leaves the battery condenser.
The method of the present invention includes, in general, the steps of measuring the rate of lint cotton exiting a battery condenser; adding a precise amount of moisture to the lint cotton between the battery condenser and a bale press based on the desired moisture content of the cotton bale, and the rate of lint cotton exiting the battery condenser; and, perhaps, measuring the moisture content of the lint cotton as it leaves the battery condenser.
One object of the present invention is to provide an accurate apparatus and method for adding a precise amount of moisture to lint cotton before the lint is tramped into a cotton bale.
Another object of the present invention is to provide an automatic model by adding a controlled and variable amount of moisture to lint cotton as it moves from the battery condenser down the lint slide on the way to the bale press based on, in part, the incoming moisture of the lint cotton (i.e., the moisture content of the lint cotton as it enters the lint slide, before moisture is added thereto) to result in a finished bale moisture equal to a final bale percent moisture dial setting or the like as set by gin management.
Another object of the present invention is to provide a manual model by adding a preset amount of moisture to each bale as the lint cotton moves down the lint slide on the way to the bale press, resulting in a finished bale that has had the percent of moisture selected on the moisture to add dial setting (set by gin management) added to the bale, regardless of the incoming moisture of the lint cotton.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is a somewhat diagrammatic elevational view of the apparatus of the present invention, shown in combination with a battery condenser, bale press and lint slide of a cotton gin.
FIG. 2 is a block diagram of the apparatus of the present invention.
FIG. 3 is a diagram showing the arrangement of FIGS. 3A-3S.
FIGS. 3A-3S, taken together and arranged as shown in FIG. 3, disclose a preferred program for controlling the programmable logic controller of the apparatus of the present invention based on, for example, a three gin stand system.
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of the apparatus of the present invention is shown in the drawings and identified by the numeral 11 . The apparatus 11 of the present invention is designed to restore moisture to lint cotton 13 passing from a battery condenser 15 to a bale press 17 down a lint slide 19 in a typical cotton gin.
The apparatus 11 includes a rate measuring means 21 for measuring the rate of lint cotton 13 exiting the battery condenser 15 , and a moisture adding means 23 for adding a precise amount of moisture to the lint cotton 13 between the battery condenser 15 and the bale press 17 based on the desired moisture content of the cotton bale B as set by gin management, etc., and the rate of lint cotton 13 exiting the battery condenser 15 as measured by the rate measuring means 21 .
The apparatus 11 preferably includes incoming moisture content measuring means 25 for measuring the moisture content of the lint cotton 13 as it leaves the battery condenser 15 for allowing the apparatus 11 to operate in an automatic model or mode to adding a precise amount of moisture to the lint cotton 13 between the battery condenser 15 and the bale press 17 based on the desired moisture content of the cotton bale B as set by gin management, etc., and the rate of lint cotton 13 exiting the battery condenser 15 as measured by the rate measuring means 21 , and the moisture content of the lint cotton 13 as it leaves the battery condenser 15 as measured by the incoming moisture content measuring means 25 .
The apparatus 11 preferably includes a programmable logic controller (PLC) 27 for monitoring and controlling the means 21 , 23 , 25 , etc.
The moisture content measuring means 25 sends a signal 28 to the PLC 27 which can be scaled by the PLC 27 to determine the moisture content of the lint cotton 13 . The moisture content measuring means 25 preferably includes an infrared (IR) sensor 29 . The IR sensor 29 is preferably a near infrared (NIR) sensor. The moisture content measuring means 25 may consist of a Moisture Register Products Smart II NIR Moisture Measuring System marketed by Moisture Register Products, a division of Aqua Measure Instrument Co., 1712 Earhart Court, La Verne, Calif. 91750-0369.
The rate measured by the rate measuring means 21 , typically referred to as the “ginning rate” of the gin, can be determined by several different mechanisms depending upon which is the most practical for the specific individual ginning system.
In a first embodiment, the rate measuring means 21 could include dual potentiometers to replace the typical speed potentiometer on the gin feeder, feed rollers controller. That is, one of the dual potentiometers will provide the feed roller speed input signal, and the other of the dual potentiometers, in conjunction with a 10 volt D.C. power supply or the like, will give an analog input (i.e., signal 30 as shown in FIG. 2) to the PLC 27 which can be scaled by the PLC 27 to determine the ginning rate of the gin stand.
In a second embodiment, the rate measuring means 21 could include a DC/DC transducer connected directly to the speed potentiometer of the gin feeder feed roller controller (the controller can be DC or AC invertor), with the output of the transducer (i.e., signal 30 as shown in FIG. 2) connected to the analog input on the PLC 27 so the PLC 27 can scale the analog input to determine the ginning rate.
In a third embodiment, a DC/DC transducer can be connected across the DC controllers armature voltage, usually denoted as Al and A 2 . The output of the transducer (i.e., signal 30 as shown in FIG. 2) is connected to the analog input on the PLC 27 so that the PLC 27 can scale the analog input to determine the ginning rate.
In a fourth embodiment, the rate measuring means 21 could include a DC sensor (e.g., an inductive proximity switch such as a Censtable AM series M12 DC inductive proximity switch, Model AM1-AN14A) used to count the teeth on the feeder roller shaft. By sending a DC pulse (i.e., signal 30 as shown in FIG. 2) to the PLC 27 as each tooth passes by the sensor, the speed of the lint cotton 13 exiting the battery condenser 15 can be determined by the PLC 27 .
The moisture adding means 23 of the apparatus 11 preferably includes a booster pump 31 coupled to an external water source 33 (e.g., a public water utility or private water system) for raising the water pressure of the water source 33 to over 50 PSI (pounds per square inch). Discharge from the booster pump 31 is connected to a ball valve 35 used to shut off the water flow when needed or desired. When the ball valve 35 is open (turned on), the pressurized water passes through a five micron filter 37 into a type B pressure regulator 39 used to control the discharge pressure to 50 PSI. A pressure gauge 41 is preferably located directly downstream of the pressure regulator 39 for displaying the controlled discharge pressure. From the pressure gauge 41 , the water passes a flow meter 43 where a DC pulse signal 45 of 182 pulses per pound of water is sent to the input module on the PLC 27 . After passing the flow meter 43 , the water enters a flow control valve 47 where the flow rate is controlled by the PLC 27 so that the desired amount of water will be discharged through the flow control valve 47 . A pressure gauge 51 is preferably located directly downstream of the flow control valve 47 for displaying the back pressure on the flow control valve 47 produced by a spray nozzle assembly 53 . The spray nozzle assembly 53 includes up to five solenoid valves 55 that are controlled by signals 57 from the PLC 27 , and a spray nozzle 59 associated with each solenoid valve 55 . The solenoid valves 55 maintain the back pressure needed to maintain a full spray pattern from each spray nozzle 59 . The apparatus 11 preferably includes five nozzles 59 aligned one behind the other above the batt (lint cotton 13 ) on the lint slide 19 , parallel to the lint slide 19 . To be certain the fan of spray leaving the nozzles 59 is of a constant width, the pressure preferably always remains at 40 pounds per square inch. Rather than pressure adjustment, nozzles 59 with orifices sizes sufficient to spray in a range of 0.1 gallon at 40 pounds per square inch to 0.5 gallon at 40 pounds per square inch, can be combined instantaneously in order to achieve the desired spray pattern. Thus, each nozzle 59 is coupled to one solenoid valve 55 to permit the nozzle combinations to change according to commands from the PLC 27 . The various components 31 , 33 , 35 , 37 , 39 , 41 , 43 , 47 , 51 , 55 and 59 are preferably joined together in a fluid-tight manner by standard ½ inch water pipe or the like.
The apparatus 11 preferably includes a desired moisture control means 61 for being set by gin management, etc., to send a signal 63 to the PLC 27 , when the apparatus 11 is running in the automatic mode or model, to identify the desired final moisture content of the lint cotton 13 . The desired moisture control means 61 preferably consist of a Clarostat 53C3-10K potentiometer marketed by Clarostat Sensors and Controls, Inc., 12055 Rojas Drive, Suite K, El Paso, Tex. 79936, to allow the gin management, etc., to merely “dial in” the desired final moisture of the lint cotton 13 or cotton bale B.
In the fully automatic model or mode, the incoming moisture content measuring means 25 outs a 4-20 milliamp or 1-10 volt signal 28 to an analog input of the PLC 27 , as it continuously scans the discharge from the battery condenser 15 . This signal 28 to the PLC 27 is scaled by the PLC 27 to determine the presence of lint cotton 13 (used by the system to allow the water to spray) and the moisture content of the lint cotton 13 just prior to adding moisture to the lint cotton 13 . The potentiometer of the desired moisture control means 61 , in conjunction with a 10 volt DC power supply, is used to send an analog signal 63 to an analog input of the PLC 27 . This signal 63 is scaled by the PLC 27 to determine the final bale percent moisture desired in the automatic mode.
The apparatus 11 may include a manual added moisture control means 65 for being set by gin management, etc., to send a signal 67 to the PLC 27 , when the apparatus 11 is running in the manual mode or model, to identify the desired percent of moisture to add to the lint cotton 13 . The manual desired moisture control means 65 preferably consist of a Clarostat 53C3-10K potentiometer marketed by Clarostat Sensors and Controls, Inc., 12055 Rojas Drive, Suite K, El Paso, Tex. 79936, to allow the gin management, etc., to merely “dial in” the percent of moisture to add to the cotton lint 13 , regardless of the incoming or final moisture content of the cotton lint 13 .
In the manual model or mode, the potentiometer of the manual desired moisture control means 65 , in conjunction with a 10 volt power supply, is used to send an analog signal 67 to an analog input of the PLC 27 . This signal 67 is scaled by the PLC 27 to determine the percent of moisture to be added to the lint cotton 13 based on the ginning rate, regardless of the incoming or final moisture content of the cotton lint 13 .
The apparatus 11 may include a final moisture content measuring means 69 for measuring the moisture content of the cotton bale B after it leaves the bale press 17 . The final moisture content measuring means 69 may include a radio frequency (RF) sensor 70 . The RF sensor 70 can be mounted on the bale scales, or between the rollers 71 ′ on a roller conveyor 71 , etc. The radio frequency (RF) sensor 70 may be part of a Moisture Register Products BSP-901 RF Capacitance System marketed by Moisture Register Products, a division of Aqua Measure Instrument Co., 1712 Earhart Court, La Verne, Calif. 91750-0369.
The apparatus 11 preferably includes a control cabinet 72 for housing the PLC 27 , booster pump 31 , ball valve 35 , filter 37 , pressure regulator 39 , pressure gauge 41 , flow meter 43 , flow control valve 47 , automatic desired moisture control means 61 , and manual desired moisture control means 65 . The control cabinet 72 is preferably located as near as possible to the battery condenser 15 .
The spray nozzle assembly 53 , with the solenoid valves 55 and spray nozzles 59 , is preferably mounted over the lint slide 19 as near the battery condenser 15 as practical.
Once the control cabinet 72 and spray nozzle assembly 53 are in place, the solenoid valves 55 are connected to the PLC 27 , preferably via terminal strips. The external water supply or source 33 is connected to a water inlet port on the control cabinet . A water outlet port on the control cabinet 72 is connected to a water inlet port on the spray nozzle assembly 53 . An external air supply 73 with a pressure between 60 and 100 pounds per square inch is connected to an air inlet port on the control cabinet 72 and, indirectly through the control cabinet 72 , to the flow control valve 47 . The ginning rate signal 30 is carried to the control cabinet 72 by wire or transmitted over radio frequency to a receiver at the control cabinet 72 . The IR sensor 29 of the moisture content measuring means 25 should be mounted so it will be scanning the output of lint cotton 13 from the battery condenser 15 prior to the moisture being added to the lint cotton 13 via the spray nozzle assembly 53 . The incoming moisture content signal 28 is carried to the control cabinet 72 preferably by cables provided with the moisture content measuring means 25 . After this is completed, 110 volt AC power can be connected to a terminal strip of the control cabinet 72 at the PLC 27 . The apparatus 11 is then ready for operation.
The PLC 27 is preferably controlled by the program disclosed in FIGS. 3A-3S, taken together and arranged as shown in FIG. 3, using a signal 30 from the rate measuring means 21 (e.g., analog outputs from potentiometers, transducers or sensors as hereinabove disclosed relative to the several possible embodiments of the rate measuring means 21 ) as inputs to V2000, V2001, V2002 in the program to calculate the rate of lint cotton 13 exiting the battery condenser 15 (i.e., the ginning rate of the gin stands). The analog output or signal 63 from the automatic desired moisture control means 61 is used in the program as V2003. The analog output or signal 28 from the moisture content measuring means 25 as determined from the lint cotton 13 preferably at the discharge of the battery condenser 15 is used in the program as V2004. The program calculates the set point and stores it in V1402. The process variable is the pulses, or signals, 45 from the flow meter 43 and is stored in V1403. The PLC 27 uses the V1402 and V1403 in the internal PID loop and controls the analog 4 to 20 milliamp output (signal 49 ) which controls the flow control valve 47 . The PLC program then determines which and how many of the spray nozzles 59 should be applying moisture to the lint cotton 13 , and sends the appropriate signals 57 to the appropriate solenoid valves 55 .
The preferred method of the present invention includes the steps of measuring the incoming moisture content of the lint cotton 13 (in the automatic mode) between the battery condenser 15 and bale press 17 using, for example, the moisture content measuring means 25 ; measuring the rate of lint cotton 13 passing between the battery condenser 15 and the bale press 17 using, for example, the rate measuring means 21 ; and then adding a precise amount of moisture to the lint cotton between the battery condenser 15 and bale press 17 (i.e., on the lint slide 19 ) based on the desired moisture content of the cotton bale B, the moisture content of the lint cotton 13 between the battery condenser 15 and the bale press 17 , and the rate of lint cotton 13 passing between the battery condenser 13 and the bale press 17 using, for example, the moisture adding means 23 and PLC 27 .
As an example, assume the present invention is used with a gin having three gin stands, with one of the gin stands ginning at 10 bales of cotton per hour, another of the gin stands ginning at 12 bales of cotton per hour, and the last gin stand ginning at 8 bales of cotton per hour, resulting in a volume of 30 bales of cotton per hour (i.e., the rate measured by the rate measuring means 21 ); the moisture of the lint cotton 13 as measured by the moisture content measuring means 25 , before adding any moisture thereto, is 4%; and the desired final moisture of the finished bale is 8%. The apparatus 11 will read the rate of ginning of each gin stand every half second, add them together and divide by 3600 to obtain the ginning rate in “bales per second.” The PLC 27 will also subtract the moisture present (4% in this example) from the desired final bale moisture (8% in this example), resulting in the percent moisture to be added to the bale (4% in this example). Four percent moisture is equivalent to 20 pounds of water per bale. Therefore, in this example, the apparatus 11 will be spraying 0.1666 pounds of moisture per second (0.00833×20). The rate of ginning and amount of water needed per second is preferably recalculated every half second. The flow of water is controlled by the PLC 27 . In this example, the PLC 27 will multiply the 0.1666 pounds of water per second needed by a factor of 182 pulses per pound (the number of pulses transmitted by the flow meter 43 for each pound of water that passes through it). This results in 30.332 pulses per second needed in order to deliver the 4% moisture to the lint cotton 13 . That becomes the setpoint for the process. If the actual pulses being transmitted is above or below the setpoint, then the PLC 27 will open or close the flow control valve 47 , regulating the flow of water, until the setpoint is obtained. Note that the setpoint is recalculated each half second and has the variables (1) ginning rate, (2) moisture prior to adding moisture, and (3) final bale desired moisture.
When used in the automatic mode or model (using the automatic desired moisture control means 61 ), the present invention will add a controlled and variable amount of moisture to the lint cotton 13 as it moves from the battery condenser 15 down the lint slide 19 on the way to the bale press 17 , resulting in a finished bale moisture equal to the final bale percent moisture dial setting (set by gin management, etc.).
When used in the manual mode or model (using the manual desired moisture control means 65 ), a present amount of moisture will be added to the lint cotton, regardless of the incoming moisture, as the lint cotton 13 moves from the battery condenser 15 down the lint slide 19 on the way to the bale press 17 , resulting in a finished bale B that has had the percent of moisture set by gin management (via a moisture to add dial of the manual desired moisture control means 61 ) added to the bale B.
The difference in the manual and automatic modes or models is that the manual model puts in a preset fixed amount of moisture that takes into consideration the ginning rate and moisture to add dial setting, but not the moisture content before adding moisture to the lint cotton. The automatic model makes it calculations based on the ginning rate, the lint cotton moisture content prior to adding moisture, and the final percent moisture dial setting in determining how much moisture to add, and the moisture that is being added is recalculated every half second.
As thus constructed and used, the present invention can automatically restore moisture to the cotton lint 13 during the ginning process, using both near infrared and radio frequency sensors to deliver a very accurate moisture regardless of the incoming moisture or the rate of ginning. Advantages of the present invention include, the provision and use of incoming lint or prior bale moisture readout, final bale moisture readout to verify that the final bale moisture is correct, user defined final bale moisture, and ginning rate to determine how much moisture to add to the lint cotton 13 . Use of the present invention reduces compaction pressure required at the bale press 17 on both the tramper and the ram, increase the gin turnout (the ratio of weight of ginned lint to the weight of seed cotton), relaxes the cotton fiber, increasing the measured staple length, increases fiber strength and uniformity ratio, reduces lint fly at the bale press 17 , and results in a more uniform baled weight due to the consistent moisture.
Although the present invention has been described and illustrated with respect to a preferred embodiment and a preferred use therefor, it is not to be so limited since modifications and changes can be made therein which are within the full intended scope of the invention.
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An apparatus and method for restoring moisture to lint cotton in a cotton gin. The moisture level of lint cotton passing from a battery condenser to a bale press, and the rate of lint cotton passing from the battery condenser to the bale press are measured, and, based on those measurements and the desired moisture level of the lint cotton at the bale press, a precise amount of water is sprayed onto the lint cotton as it passes from the battery condenser to the bale press to bring the moisture level of the lint cotton at the bale press to that desired level.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority under 35 U.S.C. §119(e) to Provisional Application No. 61/785,630, filed Mar. 14, 2013, which application is hereby incorporated herein by reference in its entirety.
BACKGROUND
A. Technical Field
This invention relates generally to techniques for moving a heavy load continuously by moving a supporting floor beneath the load and, more particularly, to techniques for moving a heavy load supported on a floor consisting of multiple movable slats. If, for example, all of the slats are moved together in one direction, the load will be carried in that direction, but if the slats are returned to their starting positions in smaller groups simultaneously containing only a fraction of the total number of slats, then the frictional forces between the load and a returning group of slats will be insufficient to move the load in the reverse direction. This invention relates specifically to the infinite control of the movement of the slats to achieve desired results in movement of the load.
B. Background of the Invention
Moving floors of this type have a number of useful applications, one of which is in the collection and disposal of garbage or waste. In large cities, long distances to disposal sites have resulted in the increased use of large transfer trailers, for the temporary storage of waste gathered by collection vehicles. When a transfer trailer is full, it is towed to a disposal site for emptying. Emptying such a vehicle by tipping is cumbersome and difficult if a large trailer is used, movable floors provide an ideal solution. Typically, a rear door of the trailer is opened and the waste material is ejected through the door by operation of the moving floor.
Another useful application of a moving floor of this type is in a warehouse setting where large loads, including loads on pallets, need to be moved or moved and loaded onto trucks or between trucks. Currently a forklift is used in a warehouse setting to move large pallet loads or load pallets onto a truck or between trucks.
Systems in use prior to the present invention are sometimes referred to as “walking” floors and operate by moving all of the slats in the desired direction as far as they can travel, and then returning each slat one group at a time. These systems incorporate relatively simple hydraulic control techniques and, when a hydraulic cylinder reaches the limit of its travel, the fluid flow from a hydraulic pump must be bypassed to a holding tank until valves can switch the cylinder in the appropriate direction. Furthermore, the load cannot move forward continuously, but either has to stop or move backward for part of the time.
The principal disadvantage of prior systems of this general type is that the load movement is started and stopped repeatedly, which is clearly inefficient and time consuming. Palletized loads cannot be effectively moved using prior systems due to the large amount of skew that occurs as a result of the starting and stopping of the load and the high percent of returning slats. The time to unload is at least twice as long as it would be if the load could move continuously. In addition there are hydraulic control system disadvantages, in that the oil tends to overheat due to the need for bypassing the pump at the end of all of the strokes before the hydraulic cylinders can switch. Moreover, rather large pump flow rates are required to gain reasonable speeds. The present invention overcomes all of these disadvantages.
SUMMARY OF THE INVENTION
Embodiments of the present invention overcome the disadvantages of the prior art moving floor systems by allowing the load to move forward continuously and without skew as experienced by prior art systems. Embodiments of the present invention reside in a moving floor than can move a load at the maximum possible speed, at the lowest cost and without any overheating of the oil in the system during prolonged operation. Embodiments of the invention accomplish these goals by combining a hydraulic subsystem, including hydraulic cylinders, a pump, and control valves, with infinite piston position sensors, and an electronic control unit. The hydraulic subsystem accomplishes the desired objectives by operating a moving floor in which a majority of the slats are always moving in the desired direction of load movement. The position sensors sense the position of the pistons relative to each other. The electronic control unit uses an infinite piston positioning feedback to control the movement of the hydraulic cylinders.
Embodiments of the present invention include a plurality of elongated floor slats movable in a direction parallel to the slats, and a hydraulic system for moving the slats in a reciprocating manner such that, at any instant during operation of the system, a majority of the slats are moving in the desired direction at a predetermined speed, and a minority of the slats are moving in the opposite direction at a higher speed, for example three times the speed. The load supported by the floor will tend to move in the direction of the majority of slower moving slats at all times when the floor is operating.
A plurality of hydraulic cylinder infinite piston position sensors provide electronic feedback to the electronic control unit, which commands the electronic proportional valves that accelerate, decelerate, and control varying oil flow rates that cause all four hydraulic cylinders to function independently to provide a continuous moving floor. Three staggered stroke hydraulic cylinders propel the payload at all times while one hydraulic cylinder is retracting and as each hydraulic cylinder reaches maximum extension, it retracts and the previously retracted cylinder extends to join the other two extending hydraulic cylinders.
Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference will be made to embodiments of the invention, examples of which may be illustrated in the accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
FIG. 1 shows a functional block, in accordance with various aspects of the present invention.
FIG. 2 shows a flowchart, in accordance with various aspects of the present invention.
FIG. 3 shows a top view of mechanical, hydraulic and electronic components, in accordance with various aspects of the present invention.
FIG. 4 shows a cross sectional view of an infinite piston position sensor, in accordance with various aspects of the present invention.
FIGS. 5A and 5B shows a top view of mechanical, hydraulic and electronic components for a twenty slat system, in accordance with various aspects of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following description is set forth for purpose of explanation in order to provide an understanding of the invention. However, it is apparent that one skilled in the art will recognize that embodiments of the present invention, some of which are described below, may be incorporated into a number of different computing systems and devices. The embodiments of the present invention may be present in hardware, software or firmware. Structures shown below in the diagram are illustrative of exemplary embodiments of the invention and are meant to avoid obscuring the invention. Furthermore, connections between components within the figures are not intended to be limited to direct connections. Rather, data between these components may be modified, re-formatted or otherwise changed by intermediary components.
Reference in the specification to “one embodiment”, “in one embodiment” or “an embodiment” etc. means that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
FIG. 1 shows a functional block, in accordance with various aspects of the present invention. As described in U.S. Pat. No. 4,739,463 issued Dec. 27, 1988 and entitled “Multiphase Sliding Floor For Continuous Material Movement” (“the '468 patent”) and incorporated herein by reference, a load is moved on a movable floor in a practically continuous manner, since the majority of the slats are always moving in a desired direction. This continuity of operation provides a much more efficient and rapid load movement and also results in a more efficient hydraulic subsystem design.
In an embodiment of the present invention, a four slat moving floor system is used. In a four slat moving floor system, three of the four slats are moving in the desired direction and only one slat is moving in the direction opposite the desired direction. Therefore, the load being moved by the moving floor system is continuously moving in the desired direction. The slats are moved using hydraulic cylinders containing pistons. The present invention uses infinite piston positioning feedback to control the movement of the pistons and, therefore, the movement of the slats in the system.
As shown in FIG. 1 , movable floor 100 comprises a number of slats 110 . The slats 110 are movable and are mounted for movement in a desired direction (forward) and a direction opposite the desired direction (backward). For purpose of illustration a four slat moving floor example is used. However, it will be understood by one of ordinary skill in the art that the system could comprise practically any number of slats.
In one embodiment, each slat 110 is mounted on a cross driver 120 for mechanical support. However, the cross drivers 120 are heavy and are mounted with large screws that can cause mechanical problems. Therefore, in one embodiment, the cross drivers 120 are not used.
The slats 110 are mechanically coupled to a hydraulic cylinder system 130 . The hydraulic cylinder system 130 can comprise a plurality of hydraulic cylinders. Each hydraulic cylinder gets its power from pressurized hydraulic fluid. In one embodiment, the hydraulic fluid is oil. The hydraulic cylinder comprises a cylinder barrel housing a piston mechanically coupled to a piston rod. The barrel is closed on one end by the cylinder bottom (sometimes referred to as a cap) and the other end by the cylinder head (sometimes referred to as a gland) where the piston rod comes out of the cylinder. The piston divides the inside of the cylinder into two chambers, the bottom chamber (base end) and the piston rod side chamber (rod end). The hydraulic system also has a pump, which brings the fluid into the cylinder and a series of valves that control the flow of the fluid into the cylinder.
In one embodiment each slat is mechanically coupled to a hydraulic cylinder in the hydraulic cylinder system 130 . In another embodiment, more than one slat is mechanically coupled to a hydraulic cylinder in the hydraulic cylinder system 130 .
In one embodiment, each of the hydraulic cylinders incorporates an infinite piston position sensor 140 . The piston position sensor 140 senses the position of a piston or the piston rod. Since the hydraulic cylinder system 130 contains a plurality of pistons, each piston has a piston position sensor 140 . Therefore, the position of each piston can be determined and known relative to each other piston in the system.
The position of the pistons as sensed by the piston position sensors 140 is input into electronic control unit 150 . Electronic control unit 150 is a control unit that uses infinite piston positioning feedback to control the position of each piston in the moving floor system 100 . Based on information collected from the piston positioning sensors 140 and fed into the electronic control unit 150 , the electronic control unit 150 sends signals to proportional valves 170 . Proportional valves 170 can proportionally open and close to let control the flow of fluid to the cylinder.
In one embodiment, the electronic control unit 150 is electrically coupled to antenna 160 . Antenna 160 permits remote operation of the moving floor. It will be understood by one of ordinary skill in the art that remote operation can be accomplished using a remote control of any sort including a smart phone, tablet, laptop, personal computer, automobile, truck, or any other type of control device.
FIG. 2 shows a flowchart, in accordance with various aspects of the present invention. FIG. 2 describes the process used in moving the moving floor system of FIG. 1 . A majority of the slats are moved in the desired direction 210 . A minority of the slats are moved in the opposite direction of the desired direction 220 . For example, in the case of a four slat system, three slats are always moving forward while one slat is simultaneously moving backward. The control system of the present invention controls when the slats are moving forward and when it is moving backward.
FIG. 2 also shows sensing the position of the pistons that is used to move the slats 230 . The position of the pistons is input into the electronic control unit 240 . The movement of the pistons is determined based on the electronic control unit 250 . The proportional valves are adjusted based on the position of the pistons 260 .
FIG. 3 shows a top view of mechanical, hydraulic and electronic components, in accordance with various aspects of the present invention. FIG. 3 depicts a monoblock assembly 364 . In one embodiment, the monoblock assembly 364 is made from an aluminum material. In one embodiment, the monoblock assembly 364 is a machined electroless nickel plated aluminum block that has roller burnished hydraulic cylinder bores and internal machined passages that eliminate fittings, hoses, hydraulic tubing, and tie rods. In one embodiment, a leakproof cover can be provided for the protection of the control valves, piston position sensors, antenna, and electronic control unit. In one embodiment, hydraulic pressure and return connections are SAE and o-ring flange type.
In the example shown in FIG. 3 , the monoblock assembly 364 houses four cylinders 316 , 318 , 320 , and 322 . Each cylinder also contains a piston position sensor 324 , 326 , 328 , and 330 . In one embodiment, piston position sensors 324 , 326 , 328 , and 330 sense movement of the rod as it extends and retracts. Piston position sensors 324 , 326 , 328 , and 330 can operate in any manner such that the position of the piston is sensed. However, in one embodiment, piston position sensors 324 , 326 , 328 , and 330 detect movement of the rod and vary a voltage accordingly. Therefore, any position can be detected and it can be detected continuously.
The ability to sense piston position at any point in time and position of the piston overcomes disadvantages of the prior art systems that can only sense the position of the piston at the end of a stroke. A typical position sensor for sensing only the end of stroke uses a poppet type device that is literally contacted by the piston as it extends and causes a valve to open and retracts the cylinder. The present invention overcomes disadvantages of using this poppet typed device by using the piston position sensor and can reduce shock tremendously.
In embodiment, within monoblock assembly 364 proportional valves 336 , 338 , 340 , 342 , 344 , 346 , 348 , and 350 can adjust the flow of fluid into the cylinder in an analog fashion. The proportional valves allow the acceleration and deceleration of the pistons to be shaped such that they are smooth and therefore reduce shock. In one embodiment the proportional valves 336 , 338 , 340 , 342 , 344 , 346 , 348 , and 350 are implemented using hydraulically controlled screw in cartridge valves that screw into the monoblock assembly 364 . In one embodiment, proportional valves are solenoid operated directional valves to control the flow of oil to the cylinder. Any type of valve that can adequately control the flow of fluid into the cylinders can be used with the present invention. In one embodiment the fluid used is oil.
Valves 356 and 362 are high pressure and low pressure relief valves. Valves 358 , and 360 are two way valves. Valve 384 can be a three way valve. Line 380 is a line showing the pressurized oil. Line 382 is a line showing returning oil back. As described in the '468 patent, the hydraulic system operates using a tank (not shown), a pump, (not shown), and a sequence of valves to control the flow of oil between the tank and the cylinders.
In one embodiment of the present invention, the moving floor system uses a regenerative system. In a regenerative system, rather than collecting oil into a tank when the cylinder extends, the oil removed from rod end is reused to be put back into the system at the base end and causes retracting cylinder to retract. An advantage of using a regenerative system on a moving floor is that pump volume can be reduced.
Due to the force of regenerative systems, there are occasions when the force is too low, for example when the floor is iced over. The floor can be installed on a trailer that can be kept outside and is subject to weather conditions of the outdoors, including freezing and icing. When the floor becomes iced over, a higher pressure can be needed to break the ice. Therefore, the moving floor system allows for use of a high pressure mode when necessary. Thus, the high pressure mode enables ice to be broken from the moving floor system. Once the ice is broken and the floor is moving, the moving floor system can switch back to the regenerative system.
FIG. 3 also shows cylinders 316 , 318 , 320 and 322 are mechanically coupled to four cross drivers 304 , 306 , 308 , and 310 . Cross drivers 304 , 306 , 308 , and 310 are linked to the rods of cylinders 316 , 318 , 320 and 322 at connection points 372 , 374 , 376 , and 378 . Internal locking elements (not shown) can be used to lock the cross drivers 304 , 306 , 308 , and 310 to the hydraulic cylinder rods, thus simplifying installation of the floor. Internal locking elements are wedge shaped tapered devices that slide onto the rod locking it in place. Slats (not shown) are mechanically coupled to cross drivers 304 , 306 , 308 , and 310 at yokes 370 . In one embodiment yokes 370 can be made of polyurethane lined aluminum. The slats can be mounted perpendicular to the cross drivers 304 , 306 , 308 , and 310 and move in the same direction as the pistons.
In the embodiment shown in FIG. 3 , twenty slats can be connected to the four cross drivers 304 , 306 , 308 , and 310 . In the embodiment shown five slats can be connected to each cross driver 304 , 306 , 308 , and 310 resulting in each cylinder 316 , 318 , 320 and 322 moving five slats. As described above, each cylinder 304 , 306 , 308 , and 310 will move the slats forward for part of the time and backward for part of the time, but with three cylinders moving slats forward and one cylinder moving slats backward.
FIG. 3 also shows bearing support 302 , a mechanical structure used to support the rods when fully extended. The bearing support 302 is mechanically coupled to the rods at connection points 312 .
FIG. 3 also shows an integrated hydraulics manifold 368 . Integrated hydraulics manifold 368 houses the electronic control unit 332 and antenna 352 . Antenna 352 permits control of the moving floor by remote control 386 as described with reference to FIG. 1 . The integrated hydraulic manifold 368 can be physically mounted on the monoblock assembly 364 or it can be located separately. Electronic control unit 332 takes as input the positions of all the pistons in the system and the relative positions of the pistons and configures the control of the pistons such that the slats move in a desired fashion. The piston position sensors 324 , 326 , 328 , and 330 are electrically coupled to the electronic control unit 332 by way of electrical connection 334 . Electrical connection 334 can be a wired connection or a wireless connection using any available wired or wireless technologies.
For the purposes of simplicity of explanation, a four cylinder, four slat system will be described. However, one of ordinary skill in the art will appreciate that any number of cylinders and slats can be implemented. For ease of discussion, the four pistons will be referred to as P 1 , P 2 , P 3 , and P 4 . For example, based on the positions of the pistons, electronic control unit 332 can actuate P 1 when it travels two inches, actuate P 2 , when P 2 travels 2 inches, actuate P 3 and retract P 4 . When P 1 reaches the end, it reverses and P 4 is actuated forward. It will be understood by those of skill in the art that any appropriate distance can be used other than two inches.
Using the combination of the piston position sensors 324 , 326 , 328 , and 330 , the electronic control unit 332 , and the proportional valves 336 , 338 , 340 , 342 , 344 , 346 , 348 , and 350 permits the infinite feedback control system to operate. Using the infinite feedback control system has the advantages of moving the load faster and keeping it continuously moving, uses less horsepower, less fuel, lower pressure, less heat, and has less wear and tear than a traditional system.
FIG. 4 shows a cross sectional view of a monoblock assembly 410 including an infinite piston position sensor 405 , in accordance with various aspects of the present invention. FIG. 4 shows the piston position sensor 405 within the piston rod 430 . In one embodiment, the piston position sensor is actually inserted in the rod as shown in FIG. 4 . However, it will be understood that any infinite piston position sensor can be used. In one embodiment, a quarter inch diameter sensor is inserted into a hole in the piston rod and voltage changes to indicate position. The piston position sensor can sense very small changes in position. For example, for a six inch stroke, the piston position sensor can sense any change throughout the full stroke.
FIG. 4 also shows piston 415 mechanically coupled to piston rod 430 . FIG. 4 also shows bearings 420 , seals 425 , and rod gland 435 that operate in conjunction with piston 415 in the hydraulic system to move the piston and seal the piston such to form a seal between one chamber of the cylinder and the other.
FIGS. 5A and 5B show a top view of mechanical, hydraulic and electronic components for a twenty slat system, in accordance with various aspects of the present invention. FIG. 5A shows part of the view and FIG. 5B shows the other part. The view was split between two figures for ease of capturing the view within the constraints of the size of the page. FIG. 5A continues in FIG. 5B as indicated in the figures. FIGS. 5A and 5B are similar to FIG. 3 in that they show cylinders 544 , proportional valves 552 , and piston position sensors 542 within monoblock assembly 556 , and integrated hydraulics manifold 558 housing electronic control unit 554 and antenna 560 . Both FIGS. 5A and B and FIG. 3 show a twenty slat moving floor system. One notable difference between FIGS. 5A and B and 3 is that FIGS. 5A and B shows twenty cylinders 544 each with a corresponding piston position sensor 542 . Each cylinder 544 is mechanically coupled directly to a slat (not shown) without the use of a cross driver. There are several advantages of eliminating the need for a cross driver. One advantage is eliminating cross drivers can reduce the size of the cylinders. Additionally, cross drivers add a large amount of weight to the system and therefore reduce the amount of weight that can moved in the load. Furthermore, cross drivers are problematic due to bolts breaking and the need to access the middle of a trailer in order to repair them. Eliminating cross drivers can reduce the overall cost of the moving floor system.
The moving floor system shown in FIGS. 5A and B can effectively be considered to be the equivalent of five, four cylinder moving floor systems. The electronic control unit 554 receives piston position movement from all twenty pistons 544 and controls the movement of the pistons 544 such that at any given time fifteen of the pistons are moving forward and five of the pistons are moving backward.
It will be apparent to one of ordinary skill in the art that aspects of the present invention can be implemented as a software application running on a mobile device such as a mobile phone or a tablet computer.
While the invention has been described in conjunction with several specific embodiments, it is evident to those skilled in the art that many further alternatives, modifications and variations will be apparent in light of the foregoing description. Thus, the invention described herein is intended to embrace all such alternatives, modifications, applications, combinations, permutations, and variations as may fall within the spirit and scope of the appended claims.
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System and method for controlling a moving floor having multiple sliding slats, to produce a practically continuous load-moving force on a load carried on the apparatus. The slats are reciprocated back and forth by hydraulic cylinders, each of which controls a group of slats that are moved together. At any given time, a majority of the slats are moving together in the desired direction, and carry a load in this direction at a nearly uniform velocity. The remainder of the slats are moved in a reverse direction at the same time. The movement of the slats is controlled by an infinite piston positioning feedback system.
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BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to a fugitive ink for marking cotton modules or bales and the like wherein the ink dries rapidly in the field and does not fade or wash away upon several months exposure to the elements but wherein the ink is removed upon mechanical agitation of the fiber and the scouring/bleaching process used by textile mills.
2. Description of the Related Art
There is a recognized need for a fugitive composition to mark cotton modules or bales and other like fibers wherein the mark will not disappear or fade when the module or bale is stored in all-weather conditions open to the elements, but which can be removed when desired. Since the mark on cotton modules is applied in the field, it is also very important to provide a fast-drying material so that if the bale is exposed to rain, the dyestuff will not bleed or run on the cotton. The mark must persist notwithstanding months of exposure to rain, air, sunlight, wind, heat and cold. A further consideration for the ink is that the mark must vanish upon the mechanical agitation of the fibers and upon the scouring/bleaching processes of the textile mills, to which the fibers are subject as a matter of course prior to use. A further desirable property for the ink is that it be efficiently and safely dispensable, as, in particular, from an aerosol can.
A fugitive ink for marking cotton bales and the like is disclosed in U.S. Pat. No. 4,505,944 to Turner. The Turner ink has had serial drawbacks as a commercial product. It has had a tendency to explode when stored in an aerosol can. It has also not proven itself amenable to efficient or complete aerosol dispersal. Further, the ink itself appears to penetrate the fibers, raising the possibility that even after substantial "decolorization," the ink could have a permanent effect.
Other references disclosing the use of various dyestuffs on cotton materials are found in U.S. Pat. Nos. 3,503,087 to Wolfe et. al., 2,959,461 to Murray et. al., and 2,802,713 and 2,802,714 to Olphin et. al. However, none appear to be concerned with the field application of a fugitive dyestuff on cotton modules.
The Wolfe ink disclosed in U.S. Pat. No. 3,503,087 does not offer the strengths needed for a composition which can withstand outdoor weather conditions, such as wind, rain, heat, cold, and sunlight. Furthermore, 3,503,087 discloses batch tinting as a means for the application of the ink to cotton modules. Based on my experience, this means of application does not produce definitive characters on the module surface.
My use of the Murray ink of U.S. Pat. No. 2,959,461 shows that it does not satisfy the necessary criteria of definitive character marking for cotton modules. Rather, its main emphasis is to provide sighting colors for textile materials. Air drying time is not critical in such an application.
I have found that the Olphin ink of U.S. Pat. No. 2,802,713 does not satisfy the requirements necessary for properly marking cotton modules. Although the U.S. Pat. No. 2,802,713 ink lends itself well to indoor textile mill environments for batch coding operations wherein one kind of yarn can be distinguished from another at a glance, it does not offer any of the requirements necessary for a fugitive ink that would be subjected to all types of outdoor weather conditions. In addition, U.S. Pat. No. 2,802,713 utilizes a potentially environmentally hazardous N-vinyl pyrrolidone component.
The Olphin ink of U.S. Pat. No. 2,802,714 requires a means of drying other than by air, and thus is not suitable for outdoor cotton module marking use.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved fugitive ink for marking cotton fibers which is particularly suitable for use on cotton bales because of its fast drying properties. This ink will spray efficiently from an aerosol can, will not tend to explode when stored in the can, will offer a bright mark that does not fade upon exposure to the elements for several months, and will, leave no permanent effect upon the fibers after treatment with mechanical agitation and a scouring/bleaching process. The latter objective is furthered by an ink that tends to coat rather than penetrate the fibers. The ink will dry in two hours or less in ambient conditions in the field, thus the time for the drying of the ink is short enough to substantially remove the risk of rain occurring during the drying period. The short drying time minimizes the risk of bleeding or running of the dyestuff on the cotton, which might render the mark illegible. This is desirable since the mark identifies the owner of the module or bale, and if the mark becomes illegible during shipping or handling prior to processing, bale ownership can be difficult to determine.
The present invention produces an improved fugitive ink with a substantial absence of pigment or surfactant effect. The ink of the present invention is not wicked into the fibers. It does not chemically react with the fibers to stain them. Rather, the ink of the present invention has the tendency to coat the surface of the fibers as opposed to penetrating the fibers.
The ink is also compatible with nitrogen as a propellant. Thus, it eliminates "foaming effects" experienced in aerosol cans with previous market samples of the known prior art products. Because of the ability to use nitrogen as a propellant with the instant invention, the total contents of an aerosol container can be utilized with minimal waste.
The present invention also does not require an acid component. Thus, container failures due to acidic action on the aerosol containers can be reduced.
The ink/emulsion composition of the invention includes a water soluble dyestuff, a copolymer resin, a wetting agent and water. The ink/emulsion composition can be further cut with a diluting agent, such as water, for packaging in a dispensing container, such as an aerosol can.
The function of the polymer resin is to retain the dyestuff, such that the dye does not bleed or run-out when the applied and dried ink comes into contact with water. The wetting agent serves to improve the distribution of the dye without precipitating any bleeding. Water functions to solubilize the dyestuff.
Such a combination has been found to produce a fugitive ink that will substantially coat the fibers without penetrating. When dry, the ink withstands months of exposure to the elements such as rain, air, sunlight, wind, heat and cold. It will be removed, however, by the mechanical agitation of the fibers and scouring/bleaching processes to which the fibers are habitually subjected prior to utilization.
The stated combination of ingredients thus has the properties of being fast drying, insoluble in water when dry, no wicking of the pigment into the fibers, and the absence of staining the cotton fibers themselves through a chain of chemical changes. The ink is also amenable to aerosol application because it is compatible with compressed gases such as nitrogen or nitrous oxide as a propellant, thereby eliminating the foaming effect seen with some other products. Use of nitrogen and other inert gases as a propellant permits the total contents of the container to be efficiently dispersed, minimizing waste.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The ink/emulsion and water composition includes a water soluble dyestuff comprising by weight from about 0.2% to about 6% of the composition and a copolymer resin that comprises by weight from about 6% to about 30% of the composition. The composition further includes water comprising by weight about 60% to about 93% of the composition and a wetting agent comprising by weight about 0.09% to about 0.56% of the total composition.
In the preferred embodiment, the dye is specifically comprised of sulfone acid groups in a range, by weight, of about 0.2% to about 6% of the composition. The sulfone groups are preferred because sulfone acid groups are solubilizing agents. Pigments, on the other hand, do not contain sulfone acid groups, consequently pigments are insoluble in water.
The dye percent range of about 0.2% to about 6% has been found by trial and error to provide the best results for a fugitive ink for the definitive character marking of cotton modules. If values lower than about 0.2% are used, the ink does not produce a mark that is definitive enough to distinguish it against the background color of the cotton module composition. On the other hand, if values higher than about 6% are used, the ink bleeds due to the high ratio of resin to dye, and the markings may become illegible.
The resin range of about 6% to about 30% is necessary to accept the dye and distribute it over the cotton module surface. The resin content has to be at this level to form a quick drying brittle film.
The water range of about 60% to about 93% is found to be optimum because it offers the required functions (i.e. quick drying and weather resistance) and is economical.
The present invention utilizes an acrylic copolymer emulsion specially prepared to achieve an ink which will withstand all outdoor weather conditions. This is accomplished by maintaining a pH level of the ink and other components at between about 6 and about 8. If a pH level of the ink and other components is below 6, the ink coagulates and does not form a film. On the other hand, if the pH level is above 8, the texture of the ink becomes too soft to attain weather resistant, definitive character. By keeping the pH level within the range of about 6-8, a brittle, weather resistant, definitive character can be attained.
An acrylic polymer emulsion, sold under the trademark "NeoCryl BT-520" or "BT-5", is preferred for the resin because "BT-520" possesses good weatherability and also dries quickly in open air. To my knowledge, "BT-520" does not include acrylamide, which is a component of an Olphin ink described in aforementioned U.S. Pat. No. 2,802,714. The approximate drying time is about 1 to about 11/2 hours. Maintaining the pH level between about 6 and about 8 results in "BT-520" forming a brittle film, a desirable characteristic of the present invention.
The following examples are illustrative of the invention and do not limit the scope of the invention as described above and claimed below.
EXAMPLE 1
A red fugitive ink composition was prepared by sequentially mixing together, in the order listed, the components of Table 1.
TABLE 1______________________________________ wt % of totalComponent composition______________________________________Water 76.6A dyestuff of the azo family 3.3(C.I. Acid red 337)sold under the designation"C-K Nylanthrene red GN"which is 33% liquid.An acrylic copolymer 19.8emulsionsold under the designation"NeoCryl BT-520"A polyether modified 0.3dimethylpolysiloxane wettingagentsold under the trademark"BYK-348"______________________________________
EXAMPLE 2
A blue fugitive ink composition was prepared by sequentially mixing, in the order listed, the components of Table 2.
TABLE 2______________________________________ wt % of totalComponent composition______________________________________Water 77.7A dyestuff of the anthraquinone 2.0family (C.I. Acid blue 324)sold under the designation"C-K Nylanthrene Blue BAR"which is 67% liquidAn acrylic copolymer emulsion 20.0sold under the designation"NeoCryl BT-520"A polyether modified 0.3dimethylpolysiloxane wettingagentsold under the trademark"BYK-348"______________________________________
EXAMPLE 3
A black fugitive ink composition was prepared by mixing together, in the order listed, the components of Table 3.
TABLE 3______________________________________ wt % of totalComponent composition______________________________________Water 78.2A dyestuff of the metallized 1.4azo family (C.I. Acid Black)sold under the designation"C-K Intrachrome Black RPL"which is 50% liquidAn acrylic copolymer emulsion 20.0sold under the designation"NeoCryl BT-520"A polyether modified 0.3dimethylpolysiloxane wettingagentsold under the trademark"BYK-348"______________________________________
After applying the inks of Examples 1-3 to samples (both raw cotton and grey cotton fabric), the ink was dried for at least 4 hours, but no more than overnight. The sample was then placed into the scouring solution of Table 4, at a solution to fiber volume ratio of 30: 1, and boiled for 30 minutes. The fabric was then rinsed at a boil in tap water for several minutes. The fabric was then placed in the bleaching solution of Table 5 at room temperature and heated to 150° F. After holding for 30-60 minutes it was rinsed at 150° F. Then the fabric was rinsed with tap water of approximately 80° F.
TABLE 4______________________________________Scouring SolutionComponent Portion______________________________________Sodium Hydroxide 1.0 gSodium Carbonate 0.25 gA wetting agent 0.25 gsold by Rohm & Haas Companyunder the trademark"Triton X-100"Water 100 ml______________________________________
TABLE 5______________________________________Bleaching SolutionComponent Portion______________________________________Hydrogen Peroxide 1.5 mlSodium Silicate 0.75 gA wetting agent 0.10 gsold by Rohm & Haas Companyunder the trademark"Triton X-100"Water 100 ml______________________________________
The test fabrics were inspected for remaining ink either by eye or by placing the fabric under a black light system. In the black light system, anything other than white becomes clearly visible under the light. Results of the inspection showed that the ink was removable under the stated scouring/bleaching conditions.
The red, blue, and black fugitive inks of Examples 1-3 were also tested for their fugitive properties by applying the inks to Greige fabric. Greige fabric is fabric just off the loom or knitting machine and thus is in an unfinished state.
After applying the ink, the sample was scoured in the solution of Table 6 for 45 minutes at 180° F. and then rinsed. The fabric was then bleached in the bath of Table 7. The bleaching procedure consisted of 5 adding the fabric to the solution at a ratio of 10:1 (liquor to fabric). One half of the hydrogen peroxide was added at 130° F. and the remainder at 175° F. The bleaching was then run at 200° F. for one hour.
TABLE 6______________________________________Scouring Solution BComponent Portion______________________________________Hydrogen Peroxide 3.0 gAn extraction agent for cotton 1.5 gprocessingsold under the trademark"Lufribrol KB Lig"A surfactant 1.5 gsold under the designation"Kieralon TX-199 (NB-JET K)"Water 1 ml______________________________________
TABLE 7______________________________________Bleaching Solution BComponent Portion______________________________________An organic peroxide stabilizer 0.9 gsold under the trademark"Prestogen K"Chelate 80 1.0 gactivating agentSodium Hydroxide 4.0 gHydrogen Peroxide (35%) 7.0 gA surfactant 1.5 gsold under the trademark"Kieralon NB-OL"Water 1.0 L______________________________________
Tests on the black module marking ink of Example 3 indicate that it is durable to rain, removable under normal bleaching conditions, and removable during mechanical processing (ginning, opening, cleaning, carding, etc.). The tests on the red and blue module marking inks of Examples 1 and 2 also indicate that they are removable under normal bleaching conditions and removable during mechanical processing.
Drying time of the red, blue, and black fugitive inks of Example 1-3 were compared with that of the Turner ink described in aforementioned U.S. Pat. No. 4,505,944, which is a leading module marking product. Each ink was sprayed via aerosol can onto raw picked cotton samples. The inks were then allowed to dry for 1 hour outdoors. Weather conditions were sunny at 57° F., with a wind velocity of 9 mph. At the end of 1 hour, each sample was rinsed with water. The red, blue, and black fugitive inks remained clearly legible and did not exhibit any sign of bleeding. On the other hand, the Turner ink was not legible and bled throughout the cotton sample. Test results illustrate the improved drying time for these fugitive inks.
The above disclosed and described fugitive ink is particularly suited for, but not limited to, marking definitive characters on cotton modules or other like fibers that are stored outdoors. The fugitive ink normally dries within about 1 to 11/2 hours after application. The once dried fugitive ink remains legible and does not bleed on the modules/fibers upon several months exposure to any weather conditions, but the ink is removed upon mechanical agitation of the fiber and the scouring/bleaching process used by textile mills.
The foregoing disclosure and description of the invention and preferred embodiments are illustrative and explanatory thereof. Variations and modifications may be made, as would be apparent to those skilled in the art, without departing from the spirit of the invention. They are to be considered as within the scope of the following claims.
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This invention relates to a fugitive ink for marking cotton modules or other like fibers wherein the ink dries in less than about two hours in the field and does not fade or wash away when the module or fiber is stored in all-weather conditions open to the elements, but wherein the ink is removed upon mechanical agitation of the fiber and the scouring/bleaching process used by textile mills. The ink composition comprises a water-soluble dyestuff, such as a sulfone containing dyestuff, a polymeric resin emulsion, a wetting agent and water.
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BACKGROUND OF THE INVENTION
The present invention relates to systems that employ electronic program guides (EPGs) to assist media users in managing a large number of media-content choices, for example, television programming chatrooms, on-demand video media files, audio, etc. More specifically, the invention relates to such systems that provide “intelligence”, such as an ability to suggest choices and an ability to take actions, for example to record a program, on the user's behalf based on the user's preferences.
A common element among conventional Electronic Program Guide (EPG) systems is their ability to display listings of programs for many available channels. The listings may be generated locally and displayed interactively. The listings are commonly arranged in a grid, with each row representing a particular broadcast or cable channel, such as ABC, PBS, or ESPN and each column of the grid representing a particular time slot, such as 4:00 p.m. to 4:30 p.m. Multiple rows and multiple columns can be displayed on the screen simultaneously. The various scheduled programs or shows are arranged within the rows and columns, indicating the channels and times at which they can be found. The grid can be scrolled vertically so that a viewer can scan through different channels within a given interval of time. The grid may also be scrolled horizontally (panned) to change the time interval displayed.
Data regarding available programs may be received by a cable system or telephone line as a set of data records. Each available program may have a single corresponding data record containing information about the program such as its channel, its starting and ending times, its title, names of starring actors, whether closed-captioning and stereo are available, and perhaps a brief description of the program. It is not difficult to format a grid such as described above from this type of data records. The data spanning a period (e.g., two weeks) is typically formatted once at the server (e.g., the cable system's head-end) and broadcast repeatedly and continuously to the homes served by the cable system. Alternatively, the data may be downloaded via phone line, or other network, either on-demand or on a predetermined schedule.
An EPG system can run on a device with a user interface (hereinafter a “user interface device”), which can be a set-top box (STB), a general purpose computer, an embedded system, a controller within the television, or the server of a communications network or Internet server. The user interface device is connected to the TV to generate displays and receive input from the user. When scrolling to a new column or row, the user interface device may retrieve appropriate information from a stored database (in the user interface device or elsewhere) regarding the programming information that needs to be presented for the new row or column. For instance, when scrolling to a new column, programs falling within a new time slot need to be displayed.
In a world with too many media choices electronic program guides (EPGs) promise to make television and other media viewing manageable. Their real potential in managing large numbers of choices is in interactive “smart” systems. An interactive application of EPGs builds a user-preference database and uses the preference data to make suggestions, filter current or future programming information to simplify the job of choosing, or even make choices on behalf of the user. For example, the system could record a program without a specific request from the user.
A first type of device for building the preference database is a passive one from the standpoint of the user. The user merely makes choices in the normal fashion from raw EPG data and the system gradually builds a personal preference database by extracting a model of the user's behavior from the choices. It then uses the model to make predictions about what the user would prefer to watch in the future. This extraction process can follow simple algorithms, such as identifying apparent favorites by detecting repeated requests for the same item, or it can be a sophisticated machine-learning process such as a decision-tree technique with a large number of inputs (degrees of freedom). Such models, generally speaking, look for patterns in the user's interaction behavior (i.e., interaction with the UI for making selections).
A second type of device is more active. It permits the user to specify likes or dislikes. For example, the user can indicate, through a user interface, that dramas and action movies are favored and that certain actors are disfavored. These criteria can then be applied to predict which from among a set of programs would be preferred by the user.
An example of the first type is MbTV, a system that learns viewers' television watching preferences by monitoring their viewing patterns. MbTV operates transparently and builds a profile of a viewer's tastes. This profile is used to provide services, for example, recommending television programs the viewer might be interested in watching. MbTV learns about each of its viewer's tastes and uses what it learns to recommend upcoming programs. MbTV can help viewers schedule their television watching time by alerting them to desirable upcoming programs, and with the addition of a storage device, automatically record these programs when the viewer is absent.
MbTV has a Preference Determination Engine and a Storage Management Engine. These are used to facilitate time-shifted television. MbTV can automatically record, rather than simply suggest, desirable programming. MbTV's Storage Management Engine tries to insure that the storage device has the optimal contents. This process involves tracking which recorded programs have been viewed (completely or partially), and which are ignored. Viewers can “lock” recorded programs for future viewing in order to prevent deletion. The ways in which viewers handle program suggestions or recorded content provides additional feedback to MbTV's preference engine which uses this information to refine future decisions.
MbTV will reserve a portion of the recording space to represent each “constituent interest.” These “interests” may translate into different family members or could represent different taste categories. Though MbTV does not require user intervention, it is customizable by those that want to fine-tune its capabilities. Viewers can influence the “storage budget” for different types of programs. For example, a viewer might indicate that, though the children watch the majority of television in a household, no more than 25% of the recording space should be consumed by children's programs.
As an example of the second type of system, one EP application (EP 0854645A2) describes a system that enables a user to enter generic preferences such as a preferred program category, for example, sitcom, dramatic series, old movies, etc. The application also describes preference templates in which preference profiles can be selected, for example, one for children aged 10–12, another for teenage girls, another for airplane hobbyists, etc. This method of inputting requires that a user have the capacity to make generalizations about him/herself and that these be a true picture of his/her preferences. It can also be a difficult task for common people to answer questions about abstractions such as: “Do you like dramas or action movies?”
A PCT application (WO 97/49242 entitled System and Method for Using Television Schedule Information) is another example of the second type. It describes a system in which a user can navigate through an electronic program guide displayed in the usual grid fashion and select various programs. At each point, he may be doing any of various described tasks, including, selecting a program for recording or viewing, scheduling a reminder to watch a program, and selecting a program to designate as a favorite. Designating a program as a favorite is for the purpose, presumably, to implement a fixed rule such as: “Always display the option of watching this show” or to implement a recurring reminder. The purpose of designating favorites is not clearly described in the application. However, more importantly, for purposes of creating a preference database, when the user selects a program to designate as a favorite, she/he may be provided with the option of indicating the reason it is a favorite. The reason is indicated in the same fashion as other explicit criteria: by defining generic preferences. The only difference between this type of entry and that of other systems that rely on explicit criteria, is when the criteria are entered.
The first type of system has the advantage of being easier on the user since the user does not have to provide any explicit data. The user need merely interact with the system. For any of the various machine-learning or predictive methods to be effective, a substantial history of interaction must be available to build a useful preference database. As a result, it can take a very long time before systems of the first type can begin to perform effectively (as compared to systems of the second type). Note that the machine-learning method associated with both types of systems can be any of a variety currently known or yet to be developed, for example, decision-tree, neural network, rule-induction, nearest neighbor, or genetic algorithm techniques.
SUMMARY OF THE INVENTION
Briefly, an electronic programming guide (EPG) system employs a preference engine and processing system that learns viewers' television watching preferences by monitoring their viewing patterns. The system operates transparently to build a profile of a viewer's tastes. The profile is used to provide services, for example, recommending or automatically recording television programs that the viewer might be interested in watching. To permit the personalization of the preferences database, a user interface is provided to allow the user to simulate various kinds of interaction with the system. This allows the system to build a profile rapidly without requiring a long interaction history in real time over a number of weeks or even months to personalize the system. The invention provides a preference-data building system that permits a user to enter preference data by interacting with a user interface (“UI”) to select a favored program as if the user were selecting programs for use. In this way, the user is able to build the interaction history quickly.
To permit the entry of this “synthetic” or “simulated” interaction history, a user interface is generated and used to permit many content selections to be made in a short period of time. Fast review and selection are possible because the interaction is intended to supply preference information rather than to make actual viewing (recording, channel-blocking, etc.) selections.
In one embodiment, the UI uses old program lineups to generate an EPG display in any practical format, for example the time/channel grid format described in the background section. The system presents the user with the option of specifying programs that the user would watch, record for later viewing, lock with parental controls, etc. The categories can be further narrowed by such criteria as time of day for viewing (so the user would specify programs that would be viewed in the evening as opposed to during the day), weekday or weekend/holiday, or other indirect information. Once the kind of decision being simulated is specified, the user selects programs from the listing. In this way, the system simulates actual use of the system. The system can obtain this simulated interaction behavior in raw form and either save it in raw form or reduce it in some way for incorporation in the preference database depending on designer preferences and the type of user-modeling method being employed.
In another embodiment, the user simply selects from the EPG those programs that are preferred leaving disfavored programs unselected. Alternatively, the user can mark programs as liked and disliked. For example, using a handheld remote control, the user can use scrolling or skipping buttons, such as arrow keys, and indicate preferences with designated “Like” and “Dislike” keys. The user could make more narrow designations such as those considered as desirable for recording, desirable to block from access by children, etc.
Instead of using the grid format, a list may be generated from which redundant choices have already been deleted. The display of the list can be grouped to facilitate comprehension, for example, categories such as evening sitcoms, daytime soaps, etc. This allows intercomparison of items with common characteristics.
The content and grouping of the list may be determined in response to the user interaction. Information in the preference database may be used to help resolve ambiguities in the preference model it contains. For example, if the user likes some daytime soaps and not others, the particular features of the soaps can be resolved more clearly by providing a lot of soaps from which to select. If the user dislikes every soap presented, finer distinctions may not provide useful data and additional soaps would be culled from a candidate list of all possible programs. For another example, if the user appears to like science documentaries, more examples in the list would help the machine-learning system determine whether, for example, technology subject matter was favored over programs about nature and wildlife.
The inventive method of generating preference data has benefits over the criteria-based method of the second type. For one thing, the user may have very clear ideas about what the user likes and dislikes, but not a clear understanding of why. The invention takes advantage of what is revealed by people's raw reactions to choices to provide more accurate input to a predictive model (predictive of future likes and dislikes) than relying on the user's understanding of what the user likes or dislikes about something. Another benefit of specifying preference information in the form of simple likes and dislikes is that it may be less mentally taxing. The user's reaction to a choice of particular programs may be much faster, as well as more accurate, than abstract generalizations about likes and dislikes. Note that preference data may be specified in the form of a ranking of how much a user likes a particular program, for example, on a scale of 1 to 10.
In another embodiment, the invention accepts preferred program data from a source such as a portable memory card. The memory card is loaded with personal data that generally describes user preferences in various environments such as restaurants, computer software, movies, television shows, etc. The relevant information is extracted from the memory card and used to build or augment the preference database. The preference data stored on the memory card may be in the form of rules or criteria such as used in the second type of preference data building devices rather than program selections. These criteria-based data may be combined with the program-preference data in various ways. Two sets of weights may be applied successively to the same set of available program data, one from the program preference data and one from the criteria data. Alternatively, if the machine-learning device used for the first type data generates rules, the second-type criteria can be lumped together with these rules and applied for filtering available programming.
In another feature of the invention, programs can be marked as “Unknown” as well as “Liked” or “Disliked.” Alternatively, programs not marked can be assumed to be unknown. In such cases, this information can be used to strengthen the user profile according to the particular machine-learning device employed.
Embodiments may be a program-display system that works with an EPG system, receives input from the use (“interaction”) with one system, and measures the viewer interaction behavior. In other words, an EPG that “observes” viewer behavior and attempts to use the past viewer behavior to make the system's output more intelligent, such as by recording things the viewer does not explicitly request. To perform this function, the inventive system may have a preference data store to hold data relating to the interaction behavior. The data store could be any type of memory or storage device such as a hard disk, a server, optical drive, smart card, etc. The system also may use a schedule data store to hold program schedule data and a controller programmed to generate predictions about what the user would have done with the system had the user interacted with it. For example, the user might be away at a time a program is available for recording. In such a case, the system could record the program for the user. Also, the system can screen out material that is not likely to interest the user. To do these things, the preference engine controls a channel through which content is transmitted to an output device (be it a monitor or a recording device such as a VCR or hard disk), responsively to the preference data and current schedule.
If the user is available to make selections, the preference engine may display a list of recommended programs responsively to the predictions and the schedule data, and accept input indicating a program to be viewed now or recorded for later use. The controller is also programmed to display a list of available programs and accept input indicative of multiple favored and/or disfavored program items to help teach the system. The material does not have to be categorized and the user does not have to be concerned with the rules by which programs will be ranked by the system. The user only has to inform the system by interacting with it. The display is used for a simulated interaction, so the benefit of multiple selections can be provided in a single session. Also, the session can use old program listings. Thus, the controller is programmed to add to the preference store data that is responsive to the input without controlling a media output device to output the program. Thus, the preference data store can be loaded with new preference data without using (viewing, recording, downloading, down-sampling or otherwise transforming, redirecting, storing, interacting with as in a chat room, etc.) the programs identified.
The controller may also be programmed to generate the preference data from the user input directly, by employing a machine-learning method based on a discovery of patterns in the user input. The pattern-discovery technique may include decision-tree, neural network, rule-induction, nearest neighbor, and genetic algorithm technique, or other techniques. The latter are examples and are not intended to be limiting. The particulars involved in machine learning systems is beyond the scope of this specification, but persons of skill, given the teachings of this specification, would understand how to apply such techniques, including as-yet-unknown techniques, to the invention.
In embodiments, the invention may provide for adding preference data to an EPG system that stores prior program selections where the system has a program database containing a list of stored program identifiers identifying programs whose content is not currently, or scheduled to be, available for use. The prior program selection may be stored, or some distillation of the data may be stored. For example, to use this data to load the preference database, it might be considered immaterial what time the program had been scheduled to air. The stored “old” programs are used for training the preference part of the system and not to control output or recording of a program. A user-interface element displays the identifiers of programs and accepts user input. The user input can be single or multiple selections. The multiple selections could mean making more than one selection at the same time.
In a variation of the invention, the EPG system stores clips from various content items. In this way, a user can rely on more than just the description and title of the program to decide how and if the user would use the program or content. Interacting with the UI could be like simulated channel surfing. Alternatively, the user could just request a clip when the additional information is desired. Clips could be a sample of the content from the particular media item. For example, if the media item is a chat room, the sample could be a ten-minute chat sample, which could be compressed, if all text. If the content were video, it could be time compressed or down-sampled. If it is a television program, the clip could be a video clip. Note that the clips need not be sampled at full bandwidth. Also, thumbnail clips could be used or the clips could be displayed as frame-grabs on a thumbnail display. The display could be pruned according to techniques discussed elsewhere in the specification, particularly in connection with FIG. 11 .
The media content available may be deliverable through any kind of channel through which media is transmitted (e.g., computer network or Internet, radio signals, broadcast, multicast, dialup). A controller may be connectable to the communications channel to control delivery of the media content through the communications channel responsively to the preference data. The preferences-training feature may be implemented by insuring the controller is programmed to generate UIs just for generating preference data and regular UIs, for using the media content and secondarily generating preference data, and to supply data to the preference store from interactions with both. When displaying the regular UIs redundant entries would not be eliminated so that, for example, both occurrences of a movie airing at different times would be displayed. When displaying the UIs just for purposes of generating preference data, the redundancies can be screened out. The preference-generating UIs can be displayed as lists, thumbnails, etc. The thumbnails can be updated from the last instantiation of the media item. The controller may be programmed to accept commands to limit the identification data displayed for generating preference data. This can be done prior to the simulated interaction or automatically using the preference data as the simulated interaction proceeds. The commands to limit may include a command to omit representation in the identification data set of one or another of the predefined classes of media content. For example, the user could indicate, so to speak, “don't bother showing me any nature programs.” In this way, material in such classes would not be displayed in the list of items from which to pick. Commands may also be accepted to emphasize certain kinds of media content. So, for example, if a user frequently uses content corresponding to a certain class, finer preference distinctions could be made if a large sample from that class were scrutinized by the user and the preferences fed to the machine-learning algorithm.
In some embodiments, the invention can be described in terms of a method of updating the preference database. The steps may be as follows:
1. generate a first list of programs currently available for viewing, so that redundant entries are permitted when the entries are distinguishable only by a time of broadcast, 2. at a time of viewing, display the first list of programs, accept commands to select at least one program from the list, and control a media output device to display it, 3. generate a second list of programs scheduled to be available currently and in the future and exclude redundant entries when the redundant entries are distinguishable only by time of broadcast, 4. at a time of programming, display the second list of programs and accept commands to select multiple programs from the second list and store the multiple selections, and 5. modify the preference database responsively to the multiple selections thereby stored.
An alternative description of steps under an embodiment may include displaying a list of program categories, and accepting commands referencing the program categories; generating a list of programs scheduled to be available currently and in the future and that have been available in the past, and excluding from the list redundant entries when the redundant entries are distinguishable only by time of broadcast. Thus, the system would not eliminate, from the list, two airings of the same movie or successive episodes of the same show. The method also includes the step of modifying the list responsively to the commands referencing the program categories. At a time of programming the method may add the steps of displaying the second list of programs, accepting commands to select multiple programs from the second list, storing the multiple selections, and modifying the preference database responsively to the multiple selections without controlling an output of any of the programs identified in the multiple selections. The step of accepting commands referencing the program categories may include the step of accepting a command to emphasize programs in a selected category in some way. The step of modifying the list in that case may include increasing representation in the list of programs in the selected category as discussed above.
Variations of the method include modifying the step of generating a second list by including a step of generating a list of programs that were scheduled to be available in the past. The step of generating a second list may include displaying a list of program categories, accepting commands referencing the program categories, and excluding programs scheduled to be available currently and in the future in response to the commands referencing the program categories. The step of generating a second list may include displaying a list of program categories, accepting commands referencing the program categories, and excluding programs scheduled to be available currently and in the future (responsively to the commands referencing the program categories).
The invention will be described in connection with certain preferred embodiments, with reference to the following illustrative figures so that it may be more fully understood.
With reference to the figures, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a television/monitor displaying an EPG, with a computer to generate the EPG display, and an interaction interface suitable for use with embodiments of the invention.
FIG. 2 shows a remote control suitable for use with UI embodiments of the invention.
FIG. 3 shows an EPG display suitable for use with UI embodiments of the invention.
FIG. 4 shows a layout of physical components through which various embodiments of the invention may be realized.
FIG. 5 illustrates the flow of data in a prior art second type system in which criteria for selection of programs are specified and incorporated in a preference database and used to select programs.
FIG. 6 illustrates the flow of data in a prior art second type system which differs from the system illustrated in FIG. 1 in that program schedules are used to prompt the user to specify selection criteria.
FIG. 7 illustrates the flow of data in a first type system in which the model for predicting favored programming is derived by some machine-learning system based on user interaction with the system.
FIG. 8 illustrates the flow of data in a system according to an embodiment of the invention in which predictions are derived from a model generated from both user interaction and simulated user interaction with program guide data.
FIG. 8A illustrates the flow of data in a system in which population preference data is also used as in collaborative filtering systems.
FIG. 9 illustrates the flow of data in a system according to another embodiment of the invention in which predictions are derived from a model generated from both user interaction and simulated user interaction with program guide data and the prediction engine is used to facilitate the active entry of selection data to build up the preference database.
FIG. 9A is similar to FIG. 9 , except that preference data comes from more than one source and is synthesized in a way that makes use of collaborative filtering techniques or some other manner of using both personal and public preference data to make predictions.
FIG. 10 illustrates a selection list format for making selections of programs or other media content that are favored or disfavored.
FIG. 11 illustrates a setup UI to allow the user to omit or emphasize selected categories of content for use with the UI of FIG. 10 or others.
FIG. 12 illustrates a variation on a selection screen for making preference selections by viewing stored thumbnail clips of content tentatively selected as favored.
FIG. 13 is a flow diagram indicating the steps employed to obtain and store preference data according to various embodiments of the invention.
FIG. 14 is a flow diagram indicating steps employed to obtain and store preference data according to embodiments that permit a surfing-like style of interaction.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1–4 the invention relates to the environment of electronic program guides (EPGs). In the context of televisions, EPG is applied loosely to various features that can be delivered using a database of program information. The program information may include titles and various descriptive information such as a narrative summary, various keywords categorizing the content, etc. In an embodiment, a computer sends program information to a television 230 . Referring now also to FIGS. 2 and 3 , the program information can be shown to the user in the form of a time-grid display 170 similar to the format commonly used for existing cable television channel guides. In the time-grid display 170 , various programs are shown such as indicated by bars at 120 , 125 , 130 , 135 , and 140 . The length of each bar ( 120 – 140 ) indicates a respective program's duration and the start and end points of each bar indicate the start and end times, respectively, of each respective program. A description window 165 provides detailed information about a currently selected program. The currently selected program, Program 7 at 125 , is indicated by, for example, highlighting a colored border 137 around the currently selected program item. Various devices may be used to select programs, such as cursor keys 215 on remote control 210 .
Referring now also to FIG. 4 , the computer 240 may be equipped to receive the video signal 270 and control the channel-changing function, and to allow a user to select channels through a tuner 245 linked to the computer 240 rather than through the television's tuner 230 . The user can then select the program to be viewed by highlighting a desired selection from the displayed program schedule using the remote control 210 to control the computer. The computer 240 has a data link 260 through which it can receive updated program schedule data. This could be a telephone line connectable to an Internet service provider or some other suitable data connection. The computer 240 has a mass storage device 235 , for example a hard disk, to store program schedule information, program applications and upgrades, and other information. Information about the user's preferences and other data can be uploaded into the computer 240 via removable media such as a memory card or disk 220 . A great many interesting features are enabled by appropriately programming the computer 240 .
Note that many substitutions are possible in the above example hardware environment and all can be used in connection with the invention. The mass storage can be replaced by volatile memory or non-volatile memory. The data can be stored locally or remotely. In fact, the entire computer 240 could be replaced with a server operating offsite through a link. Rather than using a remote control to send commands to the computer 240 through an infrared port 215 , the controller could send commands through a data channel 260 which could be separate from, or the same as, the physical channel carrying the video. The video 270 or other content can be carried by a cable, RF, or any other broadband physical channel or obtained from a mass storage or removable storage medium. It could be carried by a switched physical channel such as a phone line or a virtually switched channel such as ATM or other network suitable for synchronous data communication. Content could be asynchronous and tolerant of dropouts so that present-day IP networks could be used. Further, the content of the line through which programming content is received could be audio, chat conversation data, web sites, or any other kind of content for which a variety of selections are possible. The program guide data can be received through channels other than the separate data link 260 . For example, program guide information can be received through the same physical channel as the video or other content. It could even be provided through removable data storage media such as memory card or disk 220 . The remote control 210 can be replaced by a keyboard, voice command interface, 3D-mouse, joystick, or any other suitable input device. Selections can be made by moving a highlighting indicator, identifying a selection symbolically (e.g., by a name or number), or making selections in batch form through a data transmission or via removable media. In the latter case, one or more selections may be stored in some form and transmitted to the computer 240 , bypassing the display 170 altogether. For example, batch data could come from a portable storage device (e.g. a personal digital assistant, memory card, or smart card). Such a device could have many preferences stored on it for use in various environments so as to customize the computer equipment to be used.
Referring now to FIG. 5 a prior art implementation of EPG generates a display and accepts user input. This system is of second type described in the background section. In combination, the display and the mechanism that permits data to be entered are referred to as a user interface or “UI,” in this case, a preference input UI 10 . The display shows various criteria for the user to select. These criteria correspond to characterizations of the different content that can be selected. For example, the user might be presented with such characterizations as “sports,” “cartoons,” “action movies,” and “handyman shows.” The user may select those that characterize the content the user prefers to use (by “use” it is meant such activities as: record, download, view, block from viewing by children, down-sample, route to another location, interact with such as in interacting with a chat site or Java program, or otherwise access in some way, etc.). More narrow criteria can also be specified, for example, particular programs that are favorites could be identified. This information is stored, at a time of selection of preferences, in a preference database 15 . At a later time, when the content is desired to be selected for use, these stored preferences are used to predict what choices in a current schedule database 30 the user would be likely to (or possibly, depending on the degree of scrutiny) want to use. A prediction engine 20 uses the contents of the preference database 15 and the contents of the current schedule database 20 to modify the display of currently available content selected through a selection input UI 25 . That is, the selection input UI 25 shows a currently available list of content (displayed, for example as shown in FIG. 3 ) rendered according to the contents of the preference database 15 .
Referring now to FIG. 6 , a prior art implementation of EPG also generates a display and accepts user input. This system also is of the second type described in the background section. The system of FIG. 6 is similar to that of FIG. 5 with the exception that criteria are not necessarily specified in a vacuum. That is, in one mode for the preference input UI 10 , upon designation of a favorite, the user is presented with the option of designating the criterion according to which the content is preferred. That is, the user specifies why the content is a favorite. To do this, information may be drawn from the current schedule database 30 and displayed in a time-grid format similar to what is shown in FIG. 3 . The user would select a program to watch, record, or designate as a favorite. At this time, the user would be presented with the option of giving a reason in the form of a selection from a list of characterizations pertinent to the movie. For example, the user could indicate that movies with a particular actor are favored. In other respects, the system of FIG. 6 is the same as that of FIG. 5 .
Referring now to FIG. 7 , another prior art implementation of an EPG also generates a display and accepts user input. This system, however, is of the first type described in the background section. The preference database 50 , in this case, contains the definition of a prediction model that may or may not bear any resemblance to the criterion-based database of the second type prior art systems. The data with which the preference database 50 is loaded is a predictive model based on some automated analysis of the user's prior interaction with the system. Figuratively, the system “watches” what the user selects for use and tries to “learn” what the user prefers. There are a number of well-known “machine-learning” devices for achieving this kind of prediction process. For instance, the device described in U.S. patent application entitled “ADAPTIVE TV PROGRAM RECOMMENDER”, Feb. 4, 2000, Ser. No. 09/498,271, and the device described in U.S. Pat. No. 6,727,914, entitled “METHOD AND APPARATUS FOR RECOMMENDING TELEVISION PROGRAMMING USING DECISION TREES”, both commonly assigned to the assignee of this patent application and incorporated herein by reference. The user interacts with a selection input UI 40 which is in most respects like that of the prior two figures. However, the selection input UI 40 provides data for analysis and reduction by an analysis and data reduction device 55 (the latter step could be omitted and the data transmitted in raw form), which is then stored in a preference database 50 . As the user interacts with the system, the preference database fills with increasing amounts of data. As a result, the prediction model becomes increasingly accurate. A prediction engine 45 uses the model stored in the preference database 50 and the current schedule database 30 to generate the selection input UI 40 . The system of FIG. 7 is a passive system in that there is no UI element required to add data to the preference database (although, at least certain preferences, such as ergonomic features, and other generic environmental parameters will likely be stored through an active UI mode).
Referring to FIG. 8 , an implementation of EPG according to an embodiment of the invention also generates a display and accepts user input. In one mode, this system is of the first type described in the background section. In this mode, the user interacts with the selection input UI 40 by selecting content desired to be used in some fashion and the system “observes” the interaction over time, building a database from which predictions can be made and used to customize the selection input UI 40 process. The embodiment of FIG. 8 , however, permits the user to make selections to charge (“add data to”, “load”) the preference database 50 quickly for the purpose of creating a “selection history.” In other words, the user simulates the interaction with the system that would occur upon normal use.
The user interacts with a selection input UI 40 , which may be like that of the FIG. 7 embodiment. The selection input UI 40 provides data for analysis and reduction by an analysis and data reduction device 55 , before the data is stored in a preference database 50 . As in the FIG. 7 embodiment, as the user interacts with the system, the preference database 50 fills with increasing amounts of data. As a result, the prediction model stored in the preference database 50 becomes increasingly accurate. Again, the prediction engine 45 uses the model stored in the preference database 50 and the current schedule database 30 to generate the selection input UI 40 .
In the embodiment of FIG. 8 , a synthetic user interaction UI 65 element is generated to permit the user, at any time desired, to generate the equivalent of an interaction history. The synthetic user interaction UI 65 generates a selection display similar to that generated by the selection input UI 40 . The display can be as shown in FIG. 3 or as a simple list. However, in this case, the user can make multiple indications of favored, disfavored, and unknown choices rapidly by scrolling through the display and making entries. In the embodiment of FIG. 8 , the synthetic user interaction UI 65 is generated using content information from the current schedule database 30 and prior schedule database 60 . Note that although they are depicted as separate devices, physically or logically, any or all of these databases can be subsumed within the same component or contained in a single database.
Referring to FIG. 9 , another embodiment of the invention employs a prediction engine 345 that supplies information to a synthetic user interaction UI 365 . This embodiment is similar to that of FIG. 8 except that the display of content for selection by the synthetic user interaction UI 365 is controlled in response to information supplied by the prediction engine 345 . When the user interacts with the synthetic user interaction UI 365 , the choices selected for display may be altered based on error information supplied by the synthetic user interaction UI 365 . Most machine-learning methods that may be employed in connection with the invention are capable of generating estimates of the reliability of predicted selections. Using an error estimate, the synthetic user interaction UI 365 may adjust the choices it displays to help refine areas of ambiguity in the prediction model.
Referring to FIGS. 8A and 9A , the preference data employed by the prediction engine may include data from a user preference database 50 B as well as a population preference database 50 A. The user preference database 50 B could be charged with data relating to one or more local users such as the members of a family. The population preference database 50 A could be charged with data relating to a wider population. The totality of the preference data may be employed in a type of synthesis known as collaborative filtering by a prediction engine 445 / 545 . Collaborative filtering is known in various fields for using patterns in the data relating to a large population to make predictions about individual behavior. For example, population data may show that individuals that prefer one kind of book also prefer a particular other kind of book. The same kind of technique may be employed in the environment of an EPG. Preferably, the population preference database 50 A may be physically located in a separate location. Alternatively, model data derived from the population preference database 50 A may be downloaded to the local equipment on a periodic basis.
A simple way to use error estimates to speed up the process of creating a valid prediction model is to provide more program selections for which predictions have a high error and fewer program selections for which predictions have a low error. It is appropriate to keep showing low error selections in case their high reliability is based on an unreliable pattern or rule (i.e., bad statistic). Another way to do this is for the prediction model to group a number of apparently favored or disfavored selections from either schedule database 30 or 60 which exhibit more than one basis of prediction. The synthetic user interaction UI 365 could, using this information, provide a larger number of selections from this set until one of the bases of prediction became substantially stronger. In this way, the preference database 50 can be built up in the areas where it is weak.
Referring now to FIG. 10 , the synthetic user interaction UI 365 display can be a straight list of programs or other content displayed as a list rather than the typical time grid format. The list elements 420 can be derived from old schedules that are kept in the mass storage of the computer 240 . With the stripping out of duplicates and other types of programming, via the interactive scheme described with reference to FIG. 9 , a time-grid could end up being full of empty spaces. A large window 465 provides descriptive information about the particular program currently highlighted 410 . Navigation may be by any suitable means as described with reference to FIGS. 1–3 . When a program is highlighted, the user can indicate, using designated keys, whether the program is favored or disfavored. For example this could be done using the “#” 237 and “*” 238 keys of the remote control 210 in FIG. 2 to indicate favored and disfavored programs respectively. After that, some persistent highlighting as indicated at 425 could be used to indicate that a program had been visited and identified as favored or disfavored. The selections could be grouped under classifications 430 to facilitate recognition by the user.
Referring to FIG. 11 , a setup page could be employed before the simulated interaction display and input of FIG. 10 (together, synthetic user interaction UI 65 or 365 ) to make the interaction with the UI more efficient. In this UI, for each of various classifications of content, the user can indicate whether the user tends to use a great deal of such content or essentially none of such content. For example, by checking the check box 455 , the user could indicate that the user does not want to use any Daytime programs. The window 480 can be provided to give a fuller definition of a currently selected classification by clicking on a HELP token 470 . To refine the classification, the user can obtain narrower classifications to enable the user to omit certain kinds of material and emphasize other kinds of material. For example, if the user wants to use documentaries, but knows that a general class of documentaries are not useful and that another is, he can select token 465 to provide a narrower layer of classifications such as nature, historical, science, home improvement, etc.
Referring to FIG. 12 , a video-thumbnail display has a number of video thumbnails 605 that can be shown simultaneously as moving video, as static frame grabs. A currently selected thumbnail 610 may be the only one that actually plays while the others 605 remain as still frames. A scroll bar 615 permits the user to display more than the number of thumbnails that can conveniently fit on the screen. Descriptive information on the currently selected program can be displayed in the window 65 . The user can select a subset of the possible list of programs using the interface of FIG. 11 or something similar. Then the user can further select a set of programs to view. The thumbnails would be shown and the user could select a thumbnail to hear the audio. Then, by pressing an activation key, the selected thumbnail 610 could be expanded for fullscreen viewing.
The programs selecting can be stored clips from previous broadcasts. For example, current systems such as Philips® TiVO® store video content digitally on a hard drive. A large sample of material could be stored and subsequently used to create a selection set. One example of a use of this interface is shown in FIG. 13 . An interface such as shown in FIG. 11 is presented in step S 11 and commands received to cull all the available programming is received in step S 11 . The list of remaining programs after applying the filters received in step S 11 is presented in step S 12 through an interface, for example, that of FIG. 10 . Then, in step S 13 , some of these programs are selected for more detailed review and presented in the interface of FIG. 12 . The interaction of the user with the interface of FIG. 12 is then monitored in step S 15 and data derived from the interaction is used to modify the preference data in step S 16 . The interaction data can be recorded and filtered in any of a variety of ways. For example, the amount of time spent watching each selected video or the number of times the user returned to it may be used to increase a score for the programs corresponding to the video clips.
Whether the user interaction data 42 is analyzed and/or reduced in some fashion by element 55 before being incorporated in the preference database 50 depends on design considerations and the machine-learning method being used. Examples of machine-learning methods that can be used with the invention include: decision-tree, neural network, rule-induction, nearest neighbor, and genetic algorithms.
The rendering of the selection input UI 25 can be modified according to the preference engine 20 in many ways, including combinations of filtering out low-score choices and highlighting high-score choices. For example low-score channels can be filtered out altogether (e.g., only soaps and nature documentaries score low) but all other content can be displayed with highlighting used to indicate high-score subject matter.
Note that the above functionality can be achieved in the hardware environment described above with reference to FIGS. 1–4 and any of its variants as well as variants not described in this specification. The particulars are not important because the functionality can be achieved in many ways. So, for example, the preference data used by the preference engine may be stored on a piece of portable media carried by the user, which media is polled by an RF link. In this case, the media could be charged with data in a completely different environment and the preference data copied to the local EPG system via some other means such as disk, network, etc. The interconnections between components could be made via a home network such as Firewire, a spread-spectrum RF network, or any other suitable system. The components could be embedded in a television unit, combined in an Internet terminal, or provided at an offsite server. In fact, the invention is suitable for a video on-demand service with only a simple cable television located at the user's location, with all other elements implemented offsite in a server or servers serving many users. The invention is usable with static Internet content such as files, videos, web pages, database content, as well as dynamic content such as chat rooms, video forums (e.g., Netmeeting®, CUSeeMe®), and Internet broadcasts such as news programs. In the case of static content, the static content is selected as favored, and the example of a specific piece of content is used as a basis for generalization. So if a user selects a particular web site or page, the preference expressed by that “vote” will be extended to other web sites that are deemed similar, similarity being determined in ways that are similar to devices employed by search engines. In the case of dynamic content, the selections would relate to categories of content. For example, a particular chat room or video forum may only be distinguished by some category rather than by the exact content. The latter situation is similar to the way weekly programs like business news, sitcoms, weather reports, etc. are identified.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
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An electronic programming guide (EPG) system employs a preference engine and processing system that learns viewers' television watching preferences by monitoring their viewing patterns. The system operates transparently to build a profile of a viewer's tastes. The profile is used to provide services, for example, recommending or automatically recording television programs the viewer might be interested in watching. To permit the personalization of the preferences database, a user interface is provided to allow the user to simulate various kinds of interaction with the system. This allows the system to build a profile rapidly without requiring a long interaction history to personalize the system.
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PRIORITY APPLICATION
[0001] This application claims priority to U.S. provisional application Ser. No. 61/151,614, filed on Feb. 11, 2009, the contents of which are incorporated herein by reference.
TECHNICAL FIELD
[0002] The technical field relates to telecommunications, and particularly, to Acknowledgment/Negative Acknowledgment reporting.
BACKGROUND
[0003] A mobile radio communication system includes a mobile radio communication network communicating with mobile terminals or UEs (User Equipments) and with external networks. Traditionally, communications are facilitated using one or more radio base stations that provide radio coverage for one or more cell areas and control traffic to and from a cell in the system. Base stations and the mobile terminals are able to send and receive data blocks, which may comprise sequence numbers, to and from each other.
[0004] Within the framework of GSM EDGE Radio Access Network (GERAN) in 3GPP, an event-based protocol uses ACK/NACK messages that are “piggy-backed” on data packets being sent in the opposite link direction. An event is an error in the transmission detected by the receiver. According to 3GPP/GERAN 44.060, ver. 8.3.0, a Piggy-Backed ACK/NACK (PAN) report can be sent from the mobile station (MS) and/or from the base station system (BSS). The PAN report is included in the feature Fast Ack/Nack Reporting (FANR) which is part of EDGE Evolution in Release-7 of 3GPP/GERAN.
[0005] These piggy-backed ACK/NACK reports (PANs) can include a combination of Block Sequence Numbers (BSN) that identify outstanding radio data blocks and bitmaps giving ACK/NACK information of radio blocks after a specified BSN. A PAN report can include a Beginning-Of-transmission Window bit (BOW), a Starting transmitted data block Sequence Number (SSN), and an ACK/NACK bitmap (reported bitmap RB). FIG. 1 shows the different fields in a PAN report as specified in 3GPP/GERAN. The BOW field indicates whether the beginning of the window (i.e., the blocks before the SSN) is covered by the PAN report or not. The Short SSN field is the data block number of where the PAN report starts. The ACK/NACK bitmap field (reported bitmap RB) includes the actual ACK/NACK bits where each bit indicates an ACK or NACK of a certain data block specified by the Short SSN plus the position of the bit in the ACK/NACK bitmap RB. A transmit format indicator (TFI) may also be included.
[0006] The transmission of data and the PAN report from the sender to the receiver takes a certain amount of time referred to as a PAN round trip time (RTT) which includes the time associated with the sender sending a data block, the receiver receiving the data block, the data block being processed to determine if it is correctly received, generating an ACK/NACK message for that data block, transmitting the ACK/NACK message, and receiving the ACK/NACK message back at the sender. Data and PAN reports can be sent in the uplink (UL) and/or downlink (DL) direction simultaneously, which means they can be in transmission at the same time. Therefore, the sender may have just sent some data while the intended receiver of that data may have sent a PAN report back to the sender. A problem with this situation is that the sender can not know whether the data it sent arrived at the receiver before or after the PAN report was sent by the receiver.
[0007] One approach to solving this problem in 3GPP/GERAN is for the base station to inform the mobile station what round trip time (RTT), as defined above, is for that particular mobile station. The mobile station may then use that RTT when calculating whether a specific bit in the ACK/NACK bitmap (reported bitmap RB) indicating an ACK for a block or a NACK for a block is valid or not. In the current implementation for the GERAN standard, this estimated RTT is broadcasted in a semi-static fashion by the base station to all mobiles stations in a given cell with the name “BS_CV_MAX.” But a serious drawback with this approach is that the actual RTT can vary substantially both between (different types of) cells and within a given cell over time, for example, due to transport load (e.g., high load during the day, low load during night, etc.) or transport type (e.g., optical cable, microwave, satellite, etc.).
[0008] This variance in actual current RTT from the broadcast RTT produces two problems, One is that a broadcast RTT longer than the actual RTT causes NACKs to be improperly ignored. The other is that a broadcast RTT shorter than the actual RTT causes unnecessary retransmissions of data blocks. These RTT variances are particularly problematic, although not limited to, situations where data is sent uplink from the mobile station to the base station, and PANs are sent downlink from the base station to the mobile station.
[0009] FIG. 2 helps illustrate the first problem in a GERAN context. In the first scenario (solid lines), the mobile station (MS) sends a data block X that the base station system (BSS) should have received at time 2 ), unless it was lost or corrupted in transmission. The BSS sends a PAN that the MS receives at time 4 ). Since the PAN is received after the BS_CV_MAX (the broadcast RTT) expires, a NACK is registered for the data block X not properly received in time by the MS. The MS then responds to the NACK by retransmitting data block X.
[0010] In the second scenario (dotted lines) shown in FIG. 2 , the MS sends a data block Y that the BSS should have received at time 1 ), unless it was lost or corrupted in transmission. The BSS sends a PAN that the MS receives at time 3 ). Since the PAN is received before the BS_CV_MAX (the broadcast RTT) expires, the MS ignores a NACK for the data block Y and does not retransmit block Y. This action by the MS is based on the assumption that BS_CV_MAX (the broadcast RTT) matches the broadcast RTT (an estimate) with the actual RTT and that in this case the BSS could not have received the data block Y before sending the PAN to the MS. This second scenario of a BS_CV_MAX (the broadcast RTT) being longer than the actual RTT is common in real life EDGE and EDGE Evolution deployments.
[0011] FIG. 3 shows a scenario where MS sends a data block Z and the BSS sends two different PANs and where the BSS broadcasted RTT (BS_CV_MAX) defines a certain timer value for the MS. When the MS receives a PAN at time 3 ) sent at time 1 ), as shown with dotted lines, the MS validates the ACK/NACK information in the PAN with respect to the BS_CV_MAX (the broadcast RTT) and concludes that the data block Z should have been received. But because the actual RTT is longer than BS_CV_MAX (the broadcast RTT), the BSS does not explicitly NACK data block Z. However, the BSS nevertheless sets the NACK bit for data block Z in the PAN bit map RBB to “not received,” even though the actual RTT has not yet expired and it is not yet possible for the MS to determine whether data block Z was properly received. The MS wrongly concludes that the BSS should have received data block Z (RTT check) and that data block Z has been lost. As a result, the MS re-transmits data block Z unnecessarily. This scenario is an example of a BS_CV_MAX (broadcast RTT) being shorter than the actual RTT.
[0012] In addition, the MS will be confused when the PAN is received at later time 4 ) corresponding to the actual RTT indicating that data block Z is ACKed. This may cause the complete PAN report to be discarded since this is the specified action to be taken in case a NACK from one PAN report is changed to ACK in consecutive PAN reports.
[0013] These examples demonstrate that some data blocks successfully received by the BSS are unnecessarily re-transmitted. This results in wasted bandwidth, decreased spectrum efficiency, increased delays, negative end-user performance, and unnecessary use of processing and transceiving resources. One example also shows that some data blocks not successfully received by the BSS are never re-transmitted. This results in very large delays and negative end-user performance.
SUMMARY
[0014] A method, node, and system are provided that overcome problems with using inaccurate estimates of a current round trip time RTT (e.g., BS_CV_MAX) for verifying the ACK/NACK information received in an ACK/NACK report, e.g., a piggy-backed ACK/NACK (PAN). This is accomplished by de-coupling the RTT from the ACK/NACK analysis performed in the sending node that receives the ACK/NACK report. A “void” message is used in the ACK/NACK report instead of a “not received” message for the blocks where no information is available. As a result, unnecessary re-transmissions are avoided, communication delays are decreased, and spectrum and other system resources are used more efficiently.
[0015] An acknowledgement (ACK)/negative acknowledgement (NACK) report is provided from a first sending radio node to a second receiving radio node, where the first sending radio node transmits over a radio channel data blocks to the second receiving radio node. The second receiving radio node receives a signal from the first sending radio node and detects that some data blocks are correctly received and some data blocks are not correctly received. An ACK/NACK message is then generated identifying correctly received data blocks as void and not correctly received data blocks as NACKed, where void means that the second receiving radio node does not confirm that a data block is correctly received. The second receiving radio node sends the ACK/NACK message to the first sending radio node. The first sending radio node receives and decodes the ACK/NACK message and then sets the data blocks identified as NACKed to be retransmitted by the first sending radio node. The first sending radio node transmits the data blocks set to be re-transmitted to the second receiving radio node. In an example implementation, the first sending radio node immediately generates a request to retransmit data blocks identified as NACKed and performs no ACK/NACK request operation for data blocks identified as void.
[0016] Significantly, the first sending radio node's determination of which data blocks to re-transmit is independent of a round trip time (RTT) associated with the first radio node sending a data block, the second radio node receiving the data block, the data block being processed to determine if it is correctly received, generation of an ACK/NACK message for that data block, transmitting the ACK/NACK message, and receiving the ACK/NACK message at the first radio node. As a result, neither the first nor the second radio node need to determine a current RTT between them to perform the operations described above.
[0017] In example non-limiting scenarios, the first sending radio node is a mobile radio station and the second receiving radio node is a base station or the first sending radio node is a base station and the second receiving radio node is a mobile radio station.
[0018] In an example GERAN implementation, one or both of the detecting and report generating operations can be performed in a base station control node that controls the base station. Alternatively, they can be performed by the base station itself. The ACK/NACK message is a piggy-backed ACK/NACK (PAN) message sent with a data block which includes a starting sequence number for a sequence of transmitted data blocks associated with the PAN message, each data block having an associated sequence number, and a reported bit map in which each transmitted data block includes a corresponding bit that indicates whether that data block is void or NACKed. Other example ACK/NACK messages include a Packet Uplink Ack/Nack message or a Packet Downlink Ack/Nack message. Both of the detecting and generating operations may be performed in the base station or one or more of those operations may be performed in a base station controller controlling one or more base stations.
[0019] In one detailed example implementation, none of the data blocks in the ACK/NACK message are identified as ACKed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is an example of a PAN report;
[0021] FIGS. 2 and 3 illustrate example PAN situations that produce undesirable responses from the data block sender/PAN receiver;
[0022] FIG. 4 illustrates an example function block diagram of sender and receiver nodes that may be used in conjunction with the technology described in this application:
[0023] FIG. 5 is a flowchart diagram illustrating non-limiting example procedures in accordance with technology described in this application;
[0024] FIG. 6 is a function block diagram illustrating an example radio communications system in which the technology of this application can be employed;
[0025] FIG. 7 is a diagram illustrating PAN reports piggy-backed onto the RLC data blocks in a radio communications system;
[0026] FIG. 8 illustrates example transmitter and receiver windows employed in data block transmission and PAN report transmission;
[0027] FIG. 9 is an example PAN report that illustrates the problem with the ACK/NACK analysis in the mobile station being linked to the base station's broadcast roundtrip time (RTT); and
[0028] FIG. 10 is an illustration of an example PAN message in accordance with the technology described herein that may be used to decouple the roundtrip time from the ACK/NACK analysis.
DETAILED DESCRIPTION
[0029] In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, interfaces, techniques, etc. However, it will be apparent to those skilled in the art that the claimed technology may be practiced in other embodiments that depart from these specific details. That is, those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the claimed technology and are included within its spirit and scope. In some instances, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail. All statements herein reciting principles, aspects, and embodiments, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.
[0030] Thus, for example, it will be appreciated by those skilled in the art that block diagrams herein represent conceptual views of illustrative circuitry embodying the principles of the technology. Similarly, it will be appreciated various processes and functions described may be substantially represented in a computer-readable medium and can be executed by a computer or processor.
[0031] The functions of the various elements including control-related functional blocks may be provided through the use of electronic circuitry such as dedicated hardware as well as computer hardware capable of executing software. When provided by a computer processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared or distributed. Moreover, a processor or controller may include, without limitation, digital signal processor (DSP) hardware, ASIC hardware, read only memory (ROM), random access memory (RAM), and/or other storage media.
[0032] A mobile terminal connection logically represents the communication between a mobile terminal and one cell in the radio access network, and a radio link provides the actual physical radio connection between the mobile terminal and a base station associated with the cell. The mobile terminal may be represented, e.g., by a mobile station, a wireless communication terminal, a mobile cellular telephone, a Personal Communications Systems terminal, a Personal Digital Assistant (PDA), a laptop, a computer, or any other kind of device capable of radio communications.
[0033] A main advantage of the technology described below is that it is not necessary for ACK/NACK reports to be linked to or based on an estimated RTT. This solves a large problem for real deployments since it is in practice not possible to estimate RTT with the accuracy needed to avoid the problems noted in the background section. Unnecessary and/or omitted re-transmissions are thus avoided thereby decreasing delay and more efficiently using spectrum and other system resources.
[0034] FIG. 4 is a function block diagram illustrating communications with data block ACK/NACK reporting between two transceiving units. The sending node 3 sends via a transmitter application data in the form of data blocks 9 over a first communications link 5 to a receiving node 1 . A data block generator 10 receives application data and generates data blocks to be transmitted by a transmitter 2 . Each data block 9 in the sequence of data blocks typically includes a header and a payload. The header usually includes a data address specifying a recipient of the data block as well as a block sequence number (BSN) which specifies an intended position for the data block in the sequence of data blocks. Consequently, BSN equals 0 for the first data block in the sequence, BSN equals 1 for the second data block in the sequence, and so forth. In order to achieve error detection and/or correction in data blocks, redundancy information is often added, e.g., cyclic redundancy check (CRC) fields may be added.
[0035] In the receiving node 1 , a channel decoder 15 , connected to a receiver 13 , tries to decode each received data block 9 . If the decoding is successful, the channel decoder 15 outputs application data included in the received data block. The channel decoder 15 provides a report generator 17 with the block sequence number of each data block received by the receiver, provided of course that the received data block is actually received and not corrupted. Along with the BSN, the channel decoder 15 also provides the report generator 17 with ACK/NACK information relating to the data block associated with the provided BSN, i.e., information on whether or not the information associated with the provided BSN is successfully received. Based on the BSN and ACK/NACK information provided by the channel decoder 15 , the report generator 17 generates ACK/NACK reports in a predetermined format. An example of such a report format was shown in FIG. 1 .
[0036] A block generator 19 receives application data that is intended for transmission to the sending node 3 and generates a sequence of data blocks that include the received application data. One or more of the data blocks 11 includes the report generated by the report generator 17 . The report is thus “piggy-backed” onto one of the generated data blocks 11 .
[0037] The sending node 3 includes a receiver 4 which provides the data blocks 11 received over link 7 to a decoder 6 that decodes the data blocks to extract application data and to detect the report piggy-backed on one of the data blocks. The decoder 6 also sends an ACK/NACK report to a controller 8 which identifies data blocks to be retransmitted and schedules their retransmission via the block generator 10 and the transmitter 2 .
[0038] Reference is now made to the non-limiting flowchart diagram in FIG. 5 . The first sending radio node transmits over a radio channel data blocks to the second receiving radio node (step SI). The second receiving radio node receives a signal from the first sending radio node (step S 2 ), and detects that some data blocks are correctly received and some data blocks are not correctly received (step S 3 ). An ACK/NACK message is generated identifying correctly received data blocks as “void,”not correctly received data blocks as NACKed, and blocks not yet received as “void.” The term “void” means that there is no information for the data block, and therefore, the second receiving radio node does not confirm that a data block is correctly received (step S 4 ). The second receiving radio node sends the ACK/NACK message to the first sending radio node (step S 5 ), and the first radio node receives and decodes the ACK NACK message. Those data blocks identified as NACKed are set to be retransmitted by the first radio node (step S 6 ). Those data blocks identified as void are left with an unchanged state, which means they will not be re-transmitted based on this ACK/NACK message. The transmitter in the first sending radio node then transmits the data blocks set to be retransmitted to the second receiving radio node (step S 7 ).
[0039] Significantly, the first sending radio node's determination of which data blocks to retransmit is independent of a roundtrip time (RTT) associated with the first radio node sending a data block, the second radio node receiving the data block, the data block being processed to determine if it is correctly received, generation of an ACK/NACK message for that data block, transmitting the ACK/NACK message, and receiving the ACK/NACK message at the first radio node. As a result, neither the first nor the second radio node needs to determine a current RTT between them to perform the operations described in FIG. 5 .
[0040] The transceiving nodes 1 and 3 in FIG. 4 may be radio transceivers used in a wireless communication such as those specified by a wireless communications standard, non-limiting examples of which include the GSM, GPRS, EDGE, and GERAN standards. The technology is not limited to a particular type of communication system or standard and may also be employed in a wide range of cellular systems which use functions similar to those described in this application, although different terminologies may be used in other systems. Moreover, although example below assumes that the mobile station is the sending node and the base station is the receiving node, the mobile station may be the receiving node and the base station may be the sending node.
[0041] FIG. 6 illustrates a non-limiting, example radio communication system that comprises a radio access network 36 showing two base stations (BS) 32 coupled to a base station controller (BSC) 34 . In GSM/EDGE parlance, the combination of a base station controller and its base stations is referred to as a base station system (BSS). The radio access network 36 communicates with other networks represented by cloud 38 via appropriate interfaces. Each base station 32 provides communication and control with a plurality of mobile stations 30 over a radio interface in one or more cells. In FIG. 6 , base station 32 is shown communicating with mobile station 30 in a representative cell illustrated with a dashed line.
[0042] Reference is now made to the diagram in FIG. 7 which shows a packet control unit (PCU) (e.g., a PCU may be a part of a base station controller), communicating with a base transceiver station (BTS) and a mobile station (MS) using piggy-backed ACK/NACK (PAN) messages on radio link control (RLC) data blocks. Each PAN message includes 4 fields including a beginning of window (BOW) which may be one bit, a short starting sequence number (SSN), which may be 7 to 11 bits in length, a reported bitmap (RB) which may be 12 to 18 bits, and temporary flow identifier (TFI) which may be 5 bits. In order to fully appreciate the PAN report analysis, it is important to understand that the sending entity employs a transmit window and the receiving entity employs a received window.
[0043] In this regard, reference is made to the diagram in FIG. 8 which shows example transmitter and receiver windows. As illustrated, the transmitter sends data to the receiver and the receiver acknowledges transmitted data blocks using ACK/NACK messages. In each transmit window, there is a predetermined number of data blocks, and in the Figure, the transmit window is represented as an array V(B). Data block V(A) in the array is the oldest already-transmitted data block in the window that has not yet been acknowledged by the receiver, and V(S) is the next data block to be transmitted by the transmitter to the receiver in the data window. On the receiver side, V(Q) is the oldest data block not yet received and V(R) is the next data block that should be received in the BSN sequence. V(Q) is the block that determines the beginning of the receive window. The window used cannot be larger than the applied window size (WS), and thus, V(Q) plus WS corresponds to the highest BSN that can be received. The window size (WS) is negotiated between transmitter and receiver at bearer setup.
[0044] FIG. 9 is an example PAN report that illustrates the problem with the mobile station's ACK/NACK analysis being linked to/coupled with the base station's broadcast roundtrip time (RTT) as described in the background section above. This PAN message uses the example format described in FIG. 7 in which the short SSN is 10 and the reported bitmap (RB) includes 12 bits corresponding to the sequence numbers starting from the short SSN+1, which in this case includes SSN 11 through SSN 10+12=SSN 22.
[0045] A PAN message typically can only “tentatively acknowledge” a correctly-received data block. To fully acknowledge correct receipt of an RLC data block requires that the RLC data block be acknowledged in a proper control block (e.g., Packet Uplink ACK/NACK or (EGPRS) Packet Downlink ACK/NACK). This is because a PAN message usually does not have sufficient error protection, e.g., a strong enough checksum, for the level of reliability needed, and therefore, a PAN should not permanently acknowledge blocks. Accordingly, a tentative acknowledgement (ACK) for a correctly-received data block can be indicated with a 1 in the bitmap RB, and a 0 can be used to indicate an incorrectly or not received data block, corresponding to a NACK. In this example, the mobile's transmit window, V(B), ends at data block corresponding to SSN plus 8. This produces uncertainty with respect to the bits in the fields SSN+9 through SSN+12. As a result, it is unclear which bits in the bitmap are valid, and as a result, it is unclear what corresponding data blocks should be retransmitted by the mobile station. Although the mobile station has already transmitted data block 18 (SSN+8=18 is the last data block in the mobile's transmit window), it is uncertain which data blocks have actually been received by the base station and been processed in sufficient time to be included in this particular ACK/NACK bitmap RB. Recall the difficulties with the changing roundtrip times described in the background of the application. If the roundtrip is 0, a practical impossibility, then the mobile station should retransmit blocks 10 , 11 , 13 , 15 , 16 , 17 , and 18 , corresponding to the bitmap fields labeled as 0. But in the more realistic case where the roundtrip time is something greater than 0, the decision of whether to re-transmit blocks 15 , 16 , 17 , and 18 corresponding to data blocks outside of the mobile transmit window depends very much on the actual value of the often changing roundtrip time.
[0046] FIG. 10 illustrates a solution to this problem. For data blocks that are not correctly received, a 0 is placed in the corresponding bit field for that data block. See, e.g., the fields for SSN+1 and SSN+3. However, for data blocks that are tentatively correctly received, such as SSN+2 and SSN+4, there is no information set to indicate that a data block is correctly received. Instead, a “1” in those bit fields means “void”—no ACK!NACK information for this data block. So the PAN message generator in the receiving node inserts “1's” for data blocks corresponding to the SSN+5-SSN+12, indicating that there is no ACK/NACK information for those blocks. The data block indicated by SSN in the PAN is implicitly NACKed, After receiving the PAN message, the mobile station knows that data blocks 10 , 11 , and 13 need to be retransmitted. The other data blocks indicated as void, i.e., 12 and 14 - 22 , are left with an unchanged state, which means they are not re-transmitted as a response to this PAN message.
[0047] Thus, the solution shown in FIG. 10 eliminates the dependency of the bitmap from the accuracy of the roundtrip time broadcast by the base station. There is no need for the base station to continually update the current roundtrip time between the base station and the mobile station and periodically distribute that RTT to the mobile station through the broadcast channel. Instead, the base station simply determines which blocks are correctly received and which are not-correctly-received and generates the bits for the PAN bit field so that the tentatively correctly-received data blocks are marked as “void” and not-correctly-received blocks are marked as NACK. Void means that there is no ACK/NACK information. When the mobile station decodes the PAN message bit map, the mobile sets all of the NACK blocks from the bit field to be retransmitted and waits for the next ACK/NACK message with respect to the other data block identified in the bitmap as void.
[0048] Another way of expressing a non-limiting example implementation of the innovative technology in this application suitable for inclusion in a 3GPP standard GERAN type specification is provided below. Again, this is only an example and is not limiting in any way on the claims.
[0049] Interpretation of the Bitmap
[0050] If a compressed reported bitmap is received, the bitmap shall first be decompressed. The uncompressed bitmap shall then be treated as follows: Firstly, if the BOW bit in PACKET UPLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message has the value ‘1’, then the bitmap acknowledges all blocks between V(A) and (SSN−2) (modulo SNS), and the corresponding elements in V(B) shall be set to the value ACKED Also a bitmap value of ‘0’ is assumed at the bit position corresponding to (SSN−1) modulo SNS which corresponds to V(Q). If the BOW bit in MBMS DOWNLINK ACK/NACK message has the value ‘1’, then the bitmap acknowledges all blocks between V(A) and (SSN−2) (modulo SNS), and a bitmap value of ‘0’ is assumed at the bit position corresponding to (SSN−1) modulo SNS, only for the mobile station sending the message. The decision whether to set the corresponding elements in V(B) to the value ACKed is implementation specific.
[0051] Then, in case of PACKET UPLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message, for each bit in the uncompressed bitmap whose corresponding BSN value is within the transmit window, if the bit contains the value ‘1’, the corresponding element in V(B) indexed relative to SSN shall be set to the value ACKED If the bit contains the value ‘0’, the element in V(B) shall be set to the value NACKED. A bit within the uncompressed bitmap whose corresponding BSN is not within the transmit window, shall be ignored. In case of MBMS DOWNLINK ACK/NACK message, for each bit in the uncompressed bitmap whose corresponding BSN value is within the transmit window, if the bit contains the value ‘1’, it positively acknowledges the corresponding RLC data block only for the mobile station sending the message, and the decision whether to set to the value ACKED the corresponding element in V(B) indexed relative to SSN is implementation specific. If the bit contains the value ‘0’, it negatively acknowledges the corresponding RLC data block only for the mobile station sending the message, and the decision whether to set to the value NACKED the corresponding element in V(B) indexed relative to SSN is implementation specific. A bit within the uncompressed bitmap whose corresponding BSN is not within the transmit window shall be ignored.
[0052] If the EOW bit in the PACKET UPLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK, or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 or MBMS DOWNLINK ACK/NACK message has the value then bitmap value ‘0’ shall be assumed for all RLC blocks with a BSN value higher than the last entry in the bitmap but less than V(S) (i.e. [V(R)−1<BSN<V(S)] modulo SNS).
[0053] If the RLC transmitter is on the mobile station side, the bit in the bitmap contains the value ‘0’ and the number of block periods between the end of the block period used for the last transmission of the corresponding RLC data block and the beginning of the block period containing the PACKET UPLINK ACK/NACK message is less than (max(BS_CV_MAX, 1)−1) (i.e. the RLC data block was recently (re)transmitted and thus can not be validly negatively acknowledged in this particular PACKET UPLINK ACK/NACK message), the element in V(B) shall not be modified. Similarly, if the RLC transmitter is on the network side and the RLC data block cannot be validly negatively acknowledged in this particular Packet Ack/Nack message the element in V(B) shall not be modified.
[0054] In the case of a PAN field, the bitmap shall be interpreted in the same way as for the case of PACKET UPLINK ACK/NACK, EGPRS PACKET DOWNLINK ACK/NACK or EGPRS PACKET DOWNLINK ACK/NACK TYPE 2 message with the following exceptions:
[0055] 1—In RLC acknowledged mode and when the PAN is received by the network, elements of V(B) shall not be set to ACKED; any element which would be set to ACKED shall be set to TENTATIVE ACK;
[0056] 2—In the case when the PAN is received by the mobile station, the value ‘1’ received in the reported bitmap shall not modify the current value of the corresponding element in V(B); the value ‘0’ received in the reported bitmap shall set the corresponding element in V(B) to the value NACKED;
[0057] 3—-if the processing of a PAN would cause an element of V(B) to be changed from ACKED or TENTATIVE ACK to NACKED, the entire PAN field shall be ignored;
[0058] 4—if a PAN positively acknowledges a block which has not yet been transmitted (i.e. whose BSN is higher than or equal to V(S)) the entire PAN field shall be ignored;
[0059] 5—if a time-based PAN indicates a reserved value the entire PAN field shall be ignored.
[0060] NOTE: Conditions 3-5 may arise due to undetected error in the PANT or in the PAN field.
[0061] Although not as easy to implement or as robust as the preferred solution described above, another possible solution is to have the base station update the MS more frequently and rapidly with new estimates of the current RTT. For example, in the GERAN standard, the BS_CV_MAX information could be made optional in the Packet Uplink ACK/NACK (PUAN) message so that base station can update the MS of changed RTT more frequently and rapidly.
[0062] Yet another possible solution to the problems described in the background is to change the definition of SSN so that the RB is always full with valid ACK/NACK bits. To do this, the SSN for a PAN is set to V(R) (next to receive) and the bitmap provides the status of lower BSNs. This removes the “open” zero bits in the end of the bitmap such as in bit positions SSN+9-SSN+12 in FIG. 9 . Furthermore, a different value for the estimated RTT (BS CV MAX) is needed for PAN and PUAN, since the RTT of the mode of operation using PAN is lower than the mode of operation using just PUAN. If the RTT check using BS_CV_MAX remains, then the estimated RTT (BS_CV_MAX) must be differentiated between PAN operation mode and PUAN operation mode.
[0063] Although various embodiments have been shown and described in detail, the claims are not limited to any particular embodiment or example. None of the above description should be read as implying that any particular element, step, range, or function is essential such that it must be included in the scope of the claims. The scope of patented subject matter is defined only by the claims. The extent of legal protection is defined by the words recited in the allowed claims and their equivalents. Reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural and functional equivalents to the elements of the above-described preferred embodiment that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. It is not necessary for a device or method to address each and every problem sought to be solved by the present technology, for it to be encompassed by the present claims. No claim is intended to invoke paragraph 6 of 35 USC §112 unless the words “means for” or “step for” are used. Furthermore, no embodiment, feature, component, or step in this specification is intended to be dedicated to the public regardless of whether the embodiment, feature, component, or step is recited in the claims.
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A method, node, and system are provided that overcome problems with using inaccurate estimates of a current round trip time RTT for verifying the ACK/NACK information received in an ACK/NACK report, e.g., a piggy-backed ACK/NACK (PAN). This is accomplished by de-coupling the RTT from the ACK/NACK analysis performed in the sending node that receives the ACK/NACK report. As a result, unnecessary re-transmissions are avoided, communication delays are decreased, and s spectrum and other system resources are used more efficiently.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a traction device and more particularly to a snowmobile stud having an inner terminal end portion which is broken away from the remainder of the stud after installation on an endless snowmobile belt.
2. Description of the Prior Art and Objects
Studs for snowmobile tracks have been provided heretofore such as that illustrated in U.S. Pat. No. 5,234,266 issued to James R. Musselman et al on Aug. 10, 1993, U.S. Pat. No. 5,299,860 issued to Lynn J. Anderson on Apr. 5, 1994, and the U.S. Pat. No. 4,758,055 issued Lynn J. Anderson on or About Jul. 19, 1988.
Such snowmobile studs are sometimes referred to as pass-through studs each having a shank which passes through an opening in the track and integrally mounts, at one end, an integral head which bears against the inner surface of the track. A nut is threaded onto the stud on the outer surface of the track.
Another type of ice stud is that illustrated in U.S. Pat. No. 3,973,808 issued to Jansen et al on Aug. 10, 1976 and assigned to James R. Musselman. A similar type stud is illustrated in U.S. Pat. No. 3,838,894 issued to Donald G. Reedy on Oct. 1, 1994 and U.S. Pat. No. 5,401,088 issued to Edward R. Rubel on or about Mar. 28, 1995.
Each of the three latter mentioned patents discloses a snowmobile stud having an axially outer ice penetrating pointed end and an axially inner end which is received in an aperture provided in a snowmobile belt. An enlarged tool engageable midportion mounts a plate or washer which bears against the outer track surface. A so-called "T-nut" is threaded onto the threaded inner end of the shank to securely fasten the stud to the snowmobile belt. As the stud is threaded into the threaded fastener, the snowmobile belt, which is resilient, will typically compress between the washer and T-nut. After installation, depending upon the thickness of the belt, an axially inner terminal end portion of the ice stud may project axially inwardly of the threaded fastener. If the axially inwardly projecting terminal stud end happens to be aligned with the idler wheels and drive sprocket wheels, undesirable stud breakage and track vibration can result. Accordingly, it is an object of the present invention to provide a new and novel traction stud which will minimize vibration and stud breakage.
Sometimes, a backer plate is mounted on the inside of the track with apertures therethrough which receive and pass the axially inner ends of the studs before the nuts are threaded onto the axially inner ends of the studs. These backer plates are of varying thicknesses depending on the material utilized. In the prior art, if the stud is of sufficient length to allow the nut to threadedly engage the terminal end of the stud mounted on a relatively thick backer plate, when mounted on a relatively thinner backer plate, the terminal end of the stud will project axially inwardly beyond the inner face of the nut and track. Accordingly, it is an object of the present invention to provide a stud which will accommodate backer plates on the inside of the track of differing thicknesses and yet, not interfere, after installation, with the idler rollers or idler sprocket wheels.
It has been found according to the present invention, that if, after installation, the axially inner terminal end portion of the stud is removed, the remaining portion of the stud will be flush with the threaded fastener to preclude interference of the stud with the idler sprockets and drive sprocket wheels. Accordingly, it is an object of the present invention to provide a new and novel stud having an inner terminal end portion which can be easily and quickly removed from the stud after installation on a snowmobile track.
A further object of the present invention is to provide a method of making a stud and method of installing a stud which will include a break away inner end portion that is removed after the stud is installed on the track.
It has been found according to the present invention, that a slot may be cut into the stud shank to provide a gap between an axially inner terminal end and an axially outer threaded portion, but coupled thereto via a reduced thickness stem that can be broken away by the application of transverse force thereto. Accordingly, it is an object of the present invention to provide a new and novel traction device including an axially inner threaded portion having a slot cut therein to provide a reduced thickness stem coupling an axially outer threaded end portion of the snowmobile stud to the adjacent threaded portion of the shank.
It is yet another object of the present invention to provide a snowmobile stud having an axially inner threaded shank provided with an annular slot that provides an annular gap surrounding a stem having a truncated cone.
It has been found, according to the present invention, that by shaping the stem such that the smallest diameter portion thereof is axially outermost and immediately adjacent the axially outer threaded portion, that the stem, upon the application transverse force, will break away immediately adjacent to the axially outer threaded portion. Accordingly, it is an object of the present invention to provide a stud for a snowmobile belt or the like for the type described including a stem that has its smallest diameter at the axially outermost portion thereof.
It is yet a further object of the present invention to provide a traction stud of the type described including a breakaway coupling stem having a cross sectional area immediately adjacent to the axially outermost threaded portion that is smaller than any of the remaining cross sectional area of the stem.
It is another object of the present invention to provide a stud for a snowmobile track or the like including an axially inner threaded portion for fastening to a snowmobile belt and including an annular slot of the type described surrounding a frustoconically shaped stem having a side wall which converges radially inwardly in an axially outer direction.
Other objects and advantages of the present invention will become apparent to those of ordinary skill in the art as the description thereof proceeds.
SUMMARY OF THE INVENTION
A traction stud for mounting on an endless snowmobile drive belt or the like comprising an elongate rod having an elongate axis, an axially outer ground engaging end, and an opposite, axially inner track mounting end having an axially inner terminal end, and a tool engageable portion intermediate the ends; the track mounting end includes an elongate threaded shank of predetermined breadth for threadedly receiving a complementally threaded mounting nut, and a slot is cut into the elongate threaded shank axially outwardly of the terminal end to provide a break away stem having a reduced breadth relative to the predetermined breadth of the threaded shank.
DESCRIPTION OF THE DRAWINGS
The invention may be more readily understood by referring to the accompanying drawings, in which:
FIG. 1 is a side elevational view of a snowmobile incorporating a snowmobile stud constructed according to the present invention, parts of the snowmobile being broken away to more particularly illustrate the snowmobile belt and part of the snowmobile belt being illustrated partly in section to more particularly illustrate the snowmobile stud, constructed according to the present invention, after installation but prior to final assembly;
FIG. 2 is a greatly enlarged sectional side view of the portion of the track and stud illustrated in the chain line circle 2--2 of FIG. 1 subsequent to the installation but prior to having the axially inner end being broken away;
FIG. 3 is a sectional side view, similar to FIG. 2, illustrating a prior art construction;
FIG. 4 is a side elevational view of the stud, turned 90° relative to its position in FIG. 2, prior to installation;
FIG. 5 is a perspective view of a hexagonal bar stock illustrating the first step of manufacture;
FIG. 6 illustrates a subsequent step in the manufacturing process wherein the hexagonal bar stock, illustrated in FIG. 5, is machined at opposite ends;
FIG. 7 illustrates a subsequent step in the manufacture more particularly illustrating an axially inner, shank end being threaded;
FIG. 8 is a side elevational view, similar to FIG. 7, illustrating a subsequent manufacturing step wherein an annular slot is cut into the axially inner threaded shank end;
FIG. 9 is a further greatly enlarged fragmentary side elevational view of the connecting stem portion encircled in the chain line circle 9--9 of FIG. 8;
FIG. 10 is an exploded sectional side view of the ice stud prior to installation on a snowmobile belt and prior to coupling to a T-nut;
FIG. 11 is a side elevational view of the ice stud illustrating a subsequent step of the assembly after the stud is installed on a snowmobile belt; and
FIG. 12 is a side elevational view of the ice stud in a final step of assembly, illustrating the axially inner portion being broken away by a pair of pliers or the like.
DESCRIPTION OF PREFERRED EMBODIMENT
A traction stud, generally designated 10, is particularly adapted for use on a snowmobile, generally designated 12, which includes a forward rotatable drive wheel sprocket wheel 14, a rearward, rotatable idler wheel 16 and a plurality of smaller diameter idler wheels 17. An endless, resilient snowmobile track, generally designated 18, is trained around the wheels 14, 16 and 17 for movement in an endless path of travel, illustrated by the arrow 20. The track 18 may include a plurality of integral cleats 19 spaced along the outer track surface 21.
The front drive sprocket wheel 14 is mounted on a shaft 22 which is coupled to a gasoline engine (not shown) mounted on the snowmobile hull 24, as usual. The snowmobile includes a suspension system, generally designated 26, including wear strips 28 which glide along the inner surface 30 of the lower run 32 of the track 18. Such weather strips may suitably comprise nylon or other suitable plastic material.
The stud 10 may be machined from an elongate bar 34 (FIG. 5) of stainless steel stock. The stud 10 includes an enlarged, intermediate flange portion 36 having a plurality of wrench receiving flats 38 defining a multi-sided head which can be accommodated in a socket wrench or the like used to turn the stud 28 about its longitudinal axis 40 (FIG. 4). The bar 34 is machined at an axially outer end, generally designated 42, to provide a tapering or conically shaped ground engaging portion 44 which has a diameter that gradually decreases towards the tip 46.
The ground engaging portion 44 of the stud axially outward of the intermediate wrench receiving section 36 has a gradually reduced diameter in an axially outward direction and includes an axially extending, axially aligned, cylindrical recess or receptacle 48 receiving a hardened wear member or rod 49 fabricated from wear resisted material, such as tungsten, carbide, or the like. The insert 49 is detachably held in the recess 48 via a press fit and/or solder (not shown). The terminal portion of the carbide wear rod 49 has outwardly converging side faces 50 defining a conical point 51 (FIG. 4).
The opposite, axially inner track engaging end 54 of the bar 34 is threaded along its length with a uniform thread 56 (FIG. 7) for receiving the internally threaded cylindrical collar portion 58 (FIGS. 2 and 10) of a so-called T-nut, generally designated 60, having an enlarged diameter track engaging head 62 provided with two or more circumferentially spaced apart tangs 64 which penetrate into the upper inside track surface 30 of the track 18. The tangs 64 dig into the inside track surface 30 to inhibit rotation of the T-nut 60 as the stud 10 is being threaded thereon.
An annular slot 66 is cut into the track engaging threaded portion 56 to provide a narrow gap 68 which divides the thread 56 into an axially inner threaded portion 70 and an axially outer portion 72. The axial length of the slot 66 is substantially less than the axial length of the T-nut threaded collar 58 so that the collar 58 can bridge the slot 66 and simultaneously threadedly engage axially inner and outer portions 70 and 72 as the stud is being threaded into the nut 60. The axially outer portion 74 (FIG. 9), immediately adjacent the axially outer threaded section 72, of the slot 66 is cut to a deeper depth than is the axially inner slot portion 76 immediately adjacent the axially inner threaded portion 70 to provide a frusto-conically shaped stem 78 having an annular side wall 79 which converges radially inwardly in an axially outer direction. The stem 78 is integrally coupled to the axially inner threaded section 70 via an axially inner stem portion 84 of a predetermined breadth or diameter B which, as illustrated, is substantially less than one-half the breadth or diameter D of the threaded sections 70 and 72. The stem 78 is integrally coupled to the axially outer threaded section 72 via an axially outer stem portion 82 of a substantially lesser breadth or diameter b than the breadth B of coupling stem portion 84.
PRIOR ART
A prior art construction of the type illustrated in the Reedy U.S. Pat. No. 3,838,894 is illustrated in FIG. 3 and includes a stud 10A having an axially inner threaded section 56A threadedly received by a T-nut 60A having an enlarged head 62A flush with the inner track surface 30A of a track 18A. Depending on the axial thickness of a washer or grouser bar 40A, mounted atop a wrench receiving, intermediate flange 36A, the axially inner threaded end 70A of the threaded shank 56A extends inwardly of the inner track surface 30A. This projection 70A will sometimes strike the sprocket wheels 40 causing the stud 10A to fracture and/or create vibration which is disadvantageous.
THE METHOD OF MANUFACTURE
The stud 10 is manufactured from a piece of hexagonal, stainless steel bar stock 34, illustrated in FIG. 5. The axially outer end 42 of the bar is machined to provide the tapered, shaped ground engaging end 44. The opposite end is machined to provide the reduced diameter shank 54 (FIG. 6). The thread 56 is then cut into the reduced diameter shank 54 as illustrated in FIG. 7. The axially extending cylindrical slot 48 is also drilled into the ground engaging end 44 along the stud axis 40 for receiving the carbide rod 49.
The slot 66 is then cut into the threaded shank 54 to provide the tapering break-away stem 78 which is in the shape a truncated cone. The axially outer end 82 of stem 80 has a predetermined diameter or breadth b which is substantially less than the diameter or breadth B of the axially inner stem end 84 such that when side-wise or transverse force is exerted on the axially inner threaded end 70, in the direction of the arrow 81 (FIG. 11), the axially outer break away stem portion 82 will fracture or fail adjacent the axially outer threaded portion 72.
A solder drop is deposited into the end slot 48 and the hardened carbide wear member 49 is then inserted into slot 48 to the position illustrated in FIGS. 4 and 11.
THE METHOD OF INSTALLATION AND ASSEMBLY
To assemble the stud, a plurality of apertures O (FIG. 10) are cut or punched into the belt 18 so that the openings O are neither longitudinally nor transversely aligned. A threaded collar portion 58 of the T-nut 60 is inserted into each opening O from the inside 30 of the track 18. A stabilizing washer or plate 40 is then placed over the threaded stud end 54 in abutting relation with the wrench engaging flange 36 in the position illustrated in FIG. 10. The washer bearing threaded stud end 56 is then inserted into the track opening O from the outside 21 of the track 18. Instead of inserting the threaded stud end 56 into a washer 40, the threaded stud end 56 may be inserted through an opening provided in an inverted U-shaped cleat or grouser bar (not shown) conventionally found on having a snowmobile track. The thicknesses of the grouser bars or washers 40 can vary depending on the type of material.
The threaded shank portion 56 is then threadedly engaged with the T-nut sleeve 58 by means of a wrench engaging the wrench engaging flats 38 until the tangs 64 are embedded in the inside surface 30 of the belt 18 and the outer surface 61 of the T-nut head 60 is flush with the inside track surface 30 as illustrated in FIG. 11. A pair of pliers 96 is then used to grip the axially inner threaded shank portion 70 to apply side-wise force, in the direction of the direction of the arrow 81, which causes the axially inner threaded portion 70 and axially inner stem end 84 to transversely, radially outwardly bend, relative to the axially outer threaded portion 72 and relative to the axially outer stem end 82. The bending causes the radially outermost portion of the axially inner threaded section 70 to axially move toward the confronting portion of the axially outer threaded section 72 to close a portion of the gap 66 remote from the stem 78. This transverse force causes the truncated cone shaped break-away stem 78 to break, fail, or fracture along its axially outer end 82 adjacent the axially outer threaded portion 72. The resulting construction is as illustrated in FIG. 12 wherein the objectionable, axially inner projecting portion 68, 72 is removed so as not to interfere with the idler and sprocket wheels 14, 16 and 17.
It is to be understood that the drawings and descriptive matter are in all cases to be interpreted as merely illustrative of the principles of the invention, rather than as limiting the same in any way, since it is contemplated that various changes may be made in various elements to achieve like results without departing from the spirit of the invention or the scope of the appended claims.
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A traction stud for an endless snowmobile belt including an elongate rod having a ground engagable end and a threaded end which can be coupled to the track with a threaded fastener. A slot is cut into the threaded portion of the track such that the terminal end threaded portion is separated from the remaining threaded portion by a gap but coupled thereto via a reduced stem which, after installation, can be broken away so that the remaining portion of the stud shank is flush with the fastener. The invention also contemplates the method of making the stud and the method of installing the stud with a transverse slot providing a weakened break away portion which can be severed by the application of transverse force to remove the axially inner terminal end of the stud.
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This application is a 371 of PCT/CA93/0058 filed Dec. 21, 1993.
FIELD OF THE INVENTION
This invention relates to a new composition of matter, contignasterol, which is useful as an anti-inflammatory agent, an anti-allergen, as an agent used in the treatment of cardiovascular and haemodynamic disorders, and other diseases.
BACKGROUND OF THE INVENTION
Marine organisms have been the source of many steroids and a number of groups which have chemical and pharmacological activity.
An article in Journal Organic Chemistry, 1992, 57, 2996-2997, entitled "Two Unique Pentacyclic Steroids with Cis C/D Ring Junction from Xestospongia bergguistia Fromont, Powerful Inhibitors of Histamine Release", N. Shoji et al., discloses xestobergsterol A (1) (23S-16β, 23-cyclo-3α, 6α, 7β, 23-tetrahydroxy-5α, 14β-cholestan-15-one) and B (2) (23S-16β, 23-cyclo-1β, 2β, 3α, 6α, 7β, 23-hexahydroxy-5α, 14β-cholestan-15-one), potent inhibitors of histamine release from rat mast cells induced by anti-IgE, are the first report of steroids with both the C 16 /C 23 bond and cis C/D ring junction.
SUMMARY OF THE INVENTION
The invention relates to new compositions of matter, and the use of these compositions in the treatment of disease. The basic compound, contignasterol (1), as well as its related compounds, have a new chemical structure as drawn below. It belongs to the steroid class of natural products but it contains a unique set of functional groups attached to the basic cholestane steroid carbon skeleton. The combination of features which make the structure of contignasterol (1) unique are: i) the 3α-hydroxyl, ii) the 4β-hydroxyl, iii) the 6α-hydroxyl, iv) the 7β-hydroxyl, v) the 14β-hydrogen configuration, vi) the 15-ketone functionality, and vii) the cyclic hemiacetal functionality in the steroid side chain which is formed between a hydroxyl functionality at C22 and an ethanol substituent (i.e. a methylene carbon at 28 and an aldehyde carbon at 29) attached at C24. Contignasterol (1) exists as a mixture of R and S stereoisomers at C29. Otherwise the stereochemistry is as drawn in 1. ##STR1##
In broad terms, the invention pertains to a novel group of contignasterol compounds having the following generic formula: ##STR2## contignasterol nucleus (ring C/D cis) where R= ##STR3## and the trans isomer ##STR4## 14-epicontignasterol nucleus (ring C/D trans) where R= ##STR5##
The compounds identified above (1 to 9) can be used to prevent inflammatory or allergic reaction when they are administered at a concentration in the range of 0.1 to 100 mg/l, and a pharmaceutically acceptable acid or salts thereof; and a pharmaceutically acceptable carrier.
The compounds identified above (1 to 9) can be used in the treatment of cardiovascular and haemodynamic disorders, when they are administered at 0.1 to 100 mg/l in a pharmaceutically acceptable carrier.
The invention also relates to a method of treating inflammation, asthma, allergic rhinitis, rashes, psoriasis, arthritis, thrombosis and hypotension or hypertension where platelets are involved in a mammal comprising treating the mammal with a therapeutic amount of any one or more of the compounds described above (1 to 9).
DETAILED DESCRIPTION OF THE INVENTION
Contignasterol (1) was isolated from extracts of specimens of the marine sponge Petrosia contignata which were collected by R. Andersen and T. Allen at Madang, Papua New Guinea. The details of the purification and structure elucidation of contignasterol (1) have been published in an article entitled "Conginasterol, Highly Oxygenated Steroid with the `Natural` 14β Configuration from the Marine Sponge Petrosia Contignata Thiele, 1899", in the Journal of Organic Chemistry, Vol. 57, pgs. 525-528, which appeared on Jan. 17, 1992, the subject matter of which is incorporated herein by reference.
The sponge Petrosia contignata Thiele was identified by Dr. R. van Soest. A voucher specimens is deposited at the Zoological Museum of Amsterdam. We initiated studies of Petrosia contignata because its extracts were active in a L1210 in vitro cytotoxicity assay (ED 50 ≈5 μg/mL). A family of previously described poly-brominated diphenyl ethers was found to be responsible for the biological activity. Extracts of the sponge Petrosia contignata Thiele contain the highly oxygenated steroid contignasterol (1). Contignasterol is apparently the first steroid from a natural source known to have the "unnatural" 14β proton configuration. 15-Dehydro-14β-ansomagenin, a steroidal aglycon isolated from the saponins of the plant Solanum vespetilio also has the 14β proton configuration. However, the authors expressed considerable doubt about whether the 14β configuration exists in the natural product or was formed by epimerization during the workup. See: Gonzalez, A. G.; Barreira, R. F.; Francisco, C. G.; Rocia, J. A.; Lopez, E. S. Ann. Quimica 1974, 70, 250. Aplykurodins A and B, two 20-carbon isoprenoids that are possibly degraded steroids, have relative stereochemistries that would correspond to the 14β proton configuration in a putative steroidol precursor. See Miyamoto, T.; Higuchi, R.; Komori, T.; Fujioka, T.; Mihashi, K. Tetrahedron Lett. 1986, 27, 1153. The cyclic hemiacetal functionality in the side chain of contignasterol is also without precedent in previously described steroids.
Specimens of P. contignata (2.5 kg wet weight) were collected by hand using SCUBA at Madang, Papua New Guinea, and transported to Vancouver frozen over dry ice. The frozen sponge specimens were immersed in methanol (3 L) and soaked at room temperature for 48 hours. Concentration of the decanted methanol in vacuo gave an aqueous suspension (1800 mL) that was sequentially extracted with hexanes (4×500 mL) and chloroform (4×1 L). Evaporation of the combined chloroform extracts in vacuo gave a brown solid (2.1 g) that was subjected to Sephadex LH 20 chromatography (3:1 MeOH/H 2 O) and reversed-phase HPLC (3:1 MeOH/H 2 O) to give contignasterol (1) as colorless crystals (153 mg: mp 239°-41° C.).
Contignasterol (1) gave a parent ion in the EIHRMS at m/z 508.3394 Da corresponding to a molecular formula of C 29 H 48 O 7 (ΔM-0.6 mmu). The 13 C NMR spectrum of 1 contained 44 resolved resonances (see Experimental Section) and the 1 H NMR spectrum contained a number of resonances (i.e., δ 5.16) that integrated for less than one proton suggesting than the molecule existed as two slowly interconverting isomeric forms. Two of the resonances in the 13 C NMR spectrum of 1 had chemical shifts appropriate for acetal carbons (δ 95.6 (CH) and 90.4 (CH)). An HMQC experiment showed correlations from each of these two carbon resonances to resonances in the 1 H NMR spectrum of 1 that each integrated for less than one proton. These data were consistent with the presence of a hemiacetal functionality in contignasterol that was undergoing slow spontaneous epimerization. ##STR6##
Acetylation of contignasterol with acetic anhydride in pyridine gave a mixture of polyacetates that were separated on HPLC to give the tetraacetate 2 as the major product and the pentaacetate 3 as one of the minor products. Evidence for the formation of the tetraacetate 2 came from its 13 C (δ 20.4, 20.6, 20.7, 20.8, 169.1, 169.3, 169.4, 172.7) and 1 H NMR spectra (δ 1.61(s), 1.71(s), 1.82(s), and 1.88(s)) which contained resonances that could be readily assigned to the four acetyl residues (Table I). A peak at mz 616.3605 DA (C 35 H 52 O 9 ΔM-0.6 mmu) that could be assigned to a [M + (C 37 H 56 O 11 )--HOAc] fragment was the highest mass observed in the EIHRMS of the tetraacetate 2. The observation of only the expected 37 resolved resonances in the 13 C NMR spectrum of 2 (Table I) indicated that the acetylation reaction had successfully eliminated the effects of the hemiacetal epimerization that had complicated the NMR data collected on 1. Consequently, the structure of contignasterol was solved by analysis of the much simpler spectroscopic data collected on the tetraacetate 2.
Experimental Data
Contignasterol (1): obtained as colorless needles from MeOH/H 2 O (≈10:1), mp 239°-41° C.; FTIR (film) 1719 cm -1 ; 1 H NMR (500 MHz, DMSO-d 6 ) δ 6.21 (bs), 5.94 (bs), 5.72 (bs), 5.16 (bs), 4.53 (bm), 4.50 (bm), 4.34 (bs), 4.16 (bm), 4.04 (bs), 3.88 (bs), 3.78 (bt, J=10.5 Hz), 3.62 (bs), 3.22 (bt, J=9.4 Hz), 3.05 (bs), 3.00 (bs), 2.38 (bm), 2.09 (bd, J=20.0 Hz), 1.13 (s), 0.93 (s) ppm; 13 C NMR (125 MHz, DMSO-d 6 ) δ 219.4, 219.3, 95.6, 90.4, 75.2, 73.9, 73.8, 70.3, 70.2, 68.6, 68.0, 67.7, 50.7, 50.5, 46.3, 45.8, 45.0, 44.9, 41.3, 41.2, 40.0, 38.8, 38.6, 38.3, 38.2, 36.9, 35.7, 35.5, 34.6, 34.0, 32.5, 32.1, 31.9, 31.8, 23.6, 20.1, 19.6, 19.3, 19.2, 18.9, 18.8, 16.7, 16.7, 14.8 ppm; EIHRMS M + m/z 508.3394 (C 29 H 48 O 7 ΔM-0.6 mmu); EILRMS m/z 508, 490, 472, 457, 447, 408, 319, 264, 246, 221, 203, 155, 119, 109.
Contignasterol Tetraacetate (2): Contignasterol (1) (18.0 mg) was stirred in pyridine 2 mL) and acetic anhydride (2 mL) at room temperature for 18 hours. The reagents were removed in vacuo, and the resulting gum was purified using normal-phase HPLC (3:2 ethyl acetate/hexane) to yield the tetraacetate 2 (5.8 mg) and the pentaacetate 3 (≈1 mg). 2: colorless oil; [α] D +63° (CH 2 Cl 2 , c 0.34); FTIR (film) 3477, 1748, 1736 cm -1 ; 1 H NMR see Table 1; 13 C NMR see Table I; EIHRMS (M + -HOAc) m/z 616.3605 (C 35 H 52 O 9 ΔM-0.6 mmu); EILRMS m/z 616, 556, 513, 496, 436, 123, 60, 43.
Contignasterol pentaacetate (3): colorless oil; 1 H NMR (400 MHz, benzene-d 6 ) δ 0.75 (d, J=6.5 Hz, 3H), 0.76 (d, J=6.6 Hz, 3H), 0.77 (d, J=6.8 Hz, 3H), 0.94 (s, 3H), 1.24 (s, 3H), 1.54 (s, 3H), 1.80 (s, 3 H), 1.86 (s, 3H), 1.89 (s, 3H), 1.95 (s, 3H), 2.10 (dd, J=3.4, 12.4 Hz), 2.31 (dd, J=10.3, 20.0 Hz), 2.39 (bs), 3.32 (m), 5.10 (m), 5.45 (dd, J=9.0, 12.0 Hz), 5.47 (bs), 5.60 (dd, J=2.2, 9.0 Hz), 6.54 (dd, J=9.1, 10.6 Hz).
Contignasterol Reduction Product 4: NaBH 4 (21 mg) was added to a solution of contignasterol (1) (12.5 mg) in isopropyl alcohol (10 mL). The reaction mixture was stirred at room temperature for 1 hour and quenched with H 2 O (10 mL). The resulting suspension was extracted with EtOAc (2×10 mL), and the ethyl acetate layer was washed with 1N HCl (10 mL) and H 2 O (10 mL). Purification of the ethyl acetate soluble material using reversed-phase HPLC (25:75 H 2 O/MeOH) gave the reduction product 4 (7.6 mg, 61%): white solid.
Reduction Product Pentaacetate 5: Reduction product 4 (7.6 mg) was stirred in pyridine (1 mL) and acetic anhydride (1 mL) at room temperature for 17 hours. The reagents were removed in vacuo, and the resulting gum was purified on normal-phase HPLC (1:1 EtOAc/Hex) to give the pentaacetate 5: colorless oil; 1 H NMR (400 MHz, benzene-d 6 ) δ 0.74 (d, J=6.8 Hz, H27), 0.76 (d, J=6.8 Hz, H26), 0.87 (m H23), 1.03 (d, J=6.8 Hz, H21), 1.04 (s, H19), 1.07 (s, H18), 1.21 (m, H28), 1.25 (m, H1), 1.25 (m, H25), 1.26 (m, H16), 1.48 (m, H23'), 1.59 (s, OAc) 1.60 (m, H2'), 1.62 (m, H28'), 1.63 (m, H5), 1.72 (s, OAc), 1.76 (s, OAc), 1.80 (m, H17), 1.82 (s, OAc), 1.91 (m, H20), 1.99 (m, H8), 2.00 (m, H2), 2.08 (s, OAc), 2.15 (dd, J=3.6, 7.8 Hz H14), 3.54 (dd, J=5.9, 9.4 Hz, H22), 3.82 (bm, H4), 5.07 (dd, J=8.9, 11.2 Hz, H7), 5.18 (bm, H3), 5.25 (m, H15), 5.32 (dd, J=8.9, 12.2 Hz, H6), 5.75 (dd, J=2.2, 9.7 Hz, H29) ppm; EIHRMS (M + -HOAc) m/z 660.3871 (C 37 H 56 O 10 ΔM-0.2 mmu); EILRMS m/z 660, 642, 615, 600, 540.
The basic cholestane nucleus structures which makes contignasterol different from others are: i) a 3α-hydroxyl, ii) a 6α-hydroxyl, iii) a 7β-hydroxyl, iv) the 14β proton configuration and v) a 15 ketone functionality (i.e. I). The side chain R could be a) linear alkyl groups CH 3 --(CH 2 ) n -- where n=0 to 10, (b) the standard cholestane side chain II, or c) oxidized versions of these variations, including in particular the C22 hydroxyl version III and the C23 hydroxyl version IV. ##STR7##
The invention includes the following structures numbered from 1 to 9. Compound 1 consists of the contignasterol (cis) nucleus and the natural side chain R. This compound shows 43% inhibition (Table 4). Compound 2 consists of the epicontignasterol nucleus (C/D trans) and the natural side chain. This compound has been tested and shows 25% inhibition. Compound 3 has the contignasterol (cis) nucleus with a methyl acetal in the side chain. It snows 12% inhibition. The remaining compounds (4 to 9), on the basis of results to date, should be active and are easy to synthesize. ##STR8## contignasterol nucleus (ring C/D cis) where R= ##STR9## 14-epicontignasterol nucleus (ring C/D trans) where R= ##STR10##
The biological data in Table 4 below demonstrates that conversion of the hemiacetal functionality in contignasterol (1) to a methyl acetal (3) leads to a significant decrease in the potency (47% inhibition at 10 μM for 1 to 12% inhibition at 10 μM for 3). This indicates that either a hemiacetal functional group or a hydroxyl group must be present at C29 for full biological potency. It is reasonable to assume that the isopropyl group attached to C24 and the C21 methyl group in the side chain of contignasterol and 14-epicontignasterol are not required for biological activity. Side chains that are lacking the C24 isopropyl and C21 methyl groups have two less chiral centers and therefore they are much simpler to synthesize. The side chain in Compounds 4 and 7 retains the hemiacetal functional group but simply eliminates the C24 isopropyl substituent and the C21 methyl group. The side chain in Compounds 5 and 8 simply replaces the hemiacetal functional group in Compounds 4 and 7 with an alcohol functional group. The side chain in Compounds 6 and 9 places an alcohol functionality on an acyclic appendage the same number of bonds removed from the nucleus as the hydroxyl functional group in the natural side chain found in contignasterol (1) and 14-epicontignasterol (2).
Biological Activity
Anti-Allergic Activity
A major test to confirm the anti-allergic property of ccontignasterols is the histamine release from human basophils. It has been discovered that contignasterol as defined in the first paragraph of the Summary inhibits histamine release from human basophils present in the blood. We used 1×10 human blood leukocytes from allergic (allergy to grass pollen) individuals and prepared leukocytes. The leukocytes were then challenged with anti-human IgE for the release of histamine. The leukocytes were either exposed to 50 μg/ml of contignasterol or saline alone (control). The amount of histamine released from the leukocytes was measured using radioenzymatic assay. As shown in Table 1, contignasterol inhibited the release of histame by 30-40%. These results suggested that contignasterol is useful as an anti-allergic drug.
TABLE 1______________________________________ Histamine Release (% of Total)______________________________________Control (no drug), challenge with 36.4anti-IgEContignasterol (50 μg/ml), challenge 19.0with anti-IgEBasal release 9.8______________________________________
Anti-Asthma Activity
We have used the contignasterol as defined in paragraph one of the Summary to block bronchoconstriction induced in guinea pigs. Guinea pigs were sensitized to ovalbumine (OA) that can serve as an antigen. The trachea from these animals after exposure to the antigen (OA) contracted in a similar manner as to in vivo situation. Where the tissue was pretreated with contignasterol, the tissue did not significantly contract after being exposed to the antigen. Table 2 shows the protective effect of contignasterol on OA-induced contraction of tracheal tissues.
TABLE 2______________________________________Contraction (% of Maximal)Ovalbumine Contignasterol (μg/ml) treatedμg/ml) Control 1 10 50______________________________________0.001 6.6 0.00 0.00 0.000.01 12 -7.7 -8.0 0.00.1 28.6 -8.5 -8.0 0.01 34.0 27.5 6.0 5.510 46.0 30 16.0 11.1100 55.7 39 16.6 16.6300 56 39.7 29.6 22______________________________________
The data from Table 2 clearly demonstrates that contignasterol inhibited airway smooth muscle contraction induced by the antigen (OA).
Anti-Thrombolytic Activity of Contignasterol
It was discovered that contignasterol inhibited aggregation of platelets caused by platelet activating factor (PAF) and collagen. PAF is a local mediator of thrombosis. Similarly, collagen exposure of vessel walls leads to the formation of thrombolytic clot in the vessels. Therefore, prevention of the formation of blood clots has direct implication in the treatment of thrombosis and associated cardiovascular diseases.
Table 3 shows that contignasterol inhibits platelet aggregation in response to PAF and collagen.
TABLE 3______________________________________Contignasterol Concentration Aggregation (% of Control)μg/ml PAF Collagen______________________________________0 100 1005 90 7010 56 2020 44 030 28 050 0 0______________________________________
PAF and collagen were used at their maximal concentrations which induced 100% aggregation of platelets. Data from Table 3 clearly demonstrates that contignasterols are potential anti-thrombolytic agents that have usefulness in the treatment of cardiovascular diseases in which platelets have a major role.
Table 4 illustrates the relative potencies of different isomers of contignasterol against allergen-induced challenge.
TABLE 4______________________________________Isomer of Contignasterol [CONC] % Inhibition______________________________________Cis-Contignasterol (Compound 1) 10 μM 43Trans Contignasterol (Compound 2) 10 μM 25Methyl-acetal Contignasterol 10 μM 12(Compound 3)______________________________________
As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.
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Steroid compounds of the contignasterol family, including stereoisomers and pharmaceutically acceptable salts, as well as compositions containing these materials and a pharmaceutically acceptable carrier, are disclosed. The steroid compounds have a 3α-hydroxyl, a 4β-hydroxyl, a 6α-hydroxyl, a 7β-hydroxyl, a 15-ketone, a trans A/B ring juncture and a cis or trans C/D ring juncture. The compounds and compositions may be used, for example, for the prevention of inflammatory or allergic reactions, or the treatment of cardiovascular or haemodynamic disorders.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to fluid pressure operated brake systems and more particularly to an apparatus for actuating an emergency brake on loss of fluid pressure in the brake system.
2. Description of the Prior Art
Emergency brake actuators which are responsive to pressure in a brake system are used in various types of devices such as turbines, off-road vehicles and the like to prevent damage in the event of loss of system pressure. Generally these actuators include a single large compression spring which is housed within one end of a cylindrical housing to actuate the emergency brake on loss of system pressure. The other end of the cylindrical housing is used as a fluid pressure chamber for compressing the spring to release the emergency brake when the brake system is pressurized. The actuator must provide an instantaneous response to a loss of pressure in the system in order to prevent damage to the wind turbine, off-road vehicle or the like.
The compression spring is initially partially compressed within the housing to hold the emergency brake in the applied position. When the fluid system is pressurized, the pressure chamber is filled with hydraulic fluid to fully compress the spring and release the emergency brake. When fully compressed the spring must have sufficient force to not only actuate the emergency brake but to also discharge the pressurized fluid from the chamber. This can cause a momentary delay in applying the brake due to the large amount of fluid in the pressure chamber. Special care is necessary in handling and repairing these actuators since the spring force of the precompressed spring is sufficient to cause an explosion on opening the housing. Extreme caution is therefore required in order to avoid accidents on opening of the spring housing.
If a single high compression spring is used to provide the force necessary to operate the actuator, the spring force of the spring can deteriorate over time due to the high stress on the spring when fully compressed. A high compression spring can lose from 10% to 21% of its force capability if held under compression over a long period of time.
SUMMARY OF THE PRESENT INVENTION
The emergency brake actuator according to the present invention includes an independent piston and cylinder assembly and an independent precompressed spring assembly. The two assemblies are so constructed and arranged that they can be assembled and disassembled without releasing the precompressed spring assembly. The spring assembly includes one or more compression springs which are permanently mounted in a canister.
The individual springs in the spring assembly have maximum spring loads much lower than required for a single large spring and as a result are subject to a lower stress time creep effect in the order of 2%.
The piston and cylinder assembly is mounted within the canister in a coaxial relation to the spring or springs. The springs are seated at one end on the end plate of the canister and at the other end on a cup which is operatively connected to the piston and cylinder assembly to allow for full compression of the springs when the piston and cylinder assembly is pressurized to release the brake.
One of the primary advantages of this arrangement is the ability to use a small piston and cylinder assembly to compress the springs which can be depressurized in a minimum of time.
Another advantage of the invention is the ability to quickly and easily remove the piston and cylinder assembly from the spring assembly for maintenance and repair without releasing the springs which are permanently mounted in the canister.
A particularly important feature of this invention is the permanent mounting of the precompressed springs in a tamper proof canister thereby reducing the hazard of premature release of the compressed springs.
Another feature of the present invention is the provision of an oil containment reservoir to seal the piston and cylinder assembly within the spring assembly and thereby prevent contamination of the piston and cylinder assembly, while guaranteeing a leak free assembly.
Other principal features and advantages of the invention will become apparent to those skilled in the art upon review of the following drawings, the detailed description and the appended claims.
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation view of the brake actuator according to the invention shown connected to a caliper brake lever arm.
FIG. 2 is an end view of the housing.
FIG. 3 is a view taken on line 3--3 of FIG. 1 showing the pistol and cylinder assembly.
FIG. 4 is a view taken on line 4--4 of FIG. 2 showing the spring assembly disconnected from the brake lever with the springs seated on the spring retainer ring.
FIG. 5 is a view similar to FIG. 4 showing the position of the piston when the brake is set.
FIG. 6 is an exploded view partly in section showing the separation of the piston assembly from the spring assembly.
Before explaining at least one embodiment of the invention in detail it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purposes of description and should not be regarded as limiting.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The pressure release actuator 10 according to the invention as seen in FIG. 1 is shown connected to the pivot arm 12 for a caliper brake (not shown). The actuator 10 generally includes a piston and cylinder assembly 34 and a spring assembly 36. As seen in FIG. 6 the piston and cylinder assembly 34 is an independent unit which can be removed from the spring assembly 36 without releasing the springs 82 and 84 from the spring assembly 36. The actuator 10 is mounted on a fixed bracket 14. The piston and cylinder assembly 34 is connected to the pivot arm 12 by means of a rod 26 and to the fluid pressure system (not shown) through a venturi nozzle 48.
The piston and cylinder assembly 34 as seen in FIGS. 4 and 5 includes a cylinder 40 having a piston 50 mounted for axial motion therein. The cylinder 40 includes a pressure chamber 46 having a nozzle 48 mounted on one end. The piston 50 is sealed in the chamber 46 by means of a double lip seal 52 and 54. The piston 50 includes an axial passage 56 having a counterbore 58 at one end. A chamber 60 is provided at the other end of the bore 56 which is connected to the axial passage 56 by means of a spherical seat 62. The chamber 60 is sealed by means of a plug 64 having a peripheral groove 66 for an O-ring seal 68. The plug 64 is retained within the chamber 60 by means of a retainer ring 70.
A spring compressor 72 is mounted on the piston 50 in a position to compress the springs 82 and 84. The spring compressor 72 as described hereinafter includes a cylinder 73 having a radial flange 80 at one end and an end plate 74 at the other end having a central aperture 76. The compressor 72 is mounted on the piston 50 by aligning the aperture 76 on the end of the piston 50. The compressor 72 is secured to the piston by a snap ring 78 and is sealed thereto by means of a plastic sealant or an O-ring seal. A mounting plate 20 having bolt holes 21 and a central opening 42 is mounted on the end of cylinder 40 and is retained thereon by snap ring 44.
The spring assembly 36 includes a housing 18 having an end plate 22 welded to one end of the housing. The weld must go all the way around the housing for strength and sealing of the plate 22 to the housing 18. A pair of compression springs 82, 84 are shown seated at one end on the end plate 22. Although two springs are shown and described herein, it is within the contemplation of the invention to use one, two or three springs having different spring ratios depending upon the force required for a particular application.
A spring plate 86 is seated on the end of springs 82 and 84 and is permanently retained within the housing 18 by means of a bolt ring 88 which is welded to the end of the housing 18. Because of the high compression forces required for this type of application it is imperative that the springs be permanently secured to the housing 18. One form of connection would be to weld the bolt ring to the housing and thereby prevent removal of the bolt ring during repair or replacement of the piston and cylinder assembly. The outer end of plate 22 is to be connected to bracket 14 by means of bolts 16 and nuts 17. An inner cylinder 96 is provided on the inside of plate 22 and extends axially into the inner spring 84. It should be noted that the springs are partially compressed on assembly to provide a maximum spring force when fully compressed to release the brake.
The spring plate 86 includes a flat section 90 having a central opening 92 and a curved flange 94 at the outer edge. It should be noted that the opening 92 is slightly larger than the diameter of the cylinder 73 and the flange 94 is slightly smaller than the diameter of the housing 18. The diameter of the opening 92 and the diameter of the flange ring 94 are such that any lateral motion of the plate 86 will be limited by the engagement of the flange 94 with the inside of the housing. The opening 92 is such that it cannot engage the cylinder 73 on lateral movement of the plate 86.
Means are provided on the end plate 22 to limit the lateral movement of the spring 84 so that it does not engage the cylinder 72. Such means is in the form of the cylinder 96 provided on the plate 22 and located between the second spring 84 and the cylinder 73. If a greater compressive force is required a third spring (not shown) can be positioned between the first spring 82 and the second spring 84.
The piston and cylinder assembly 34 is mounted on the spring assembly 36 by aligning the holes 21 in plate 20 with the threaded holes 89 in bolt ring 88. Bolts 85 are then inserted through holes 21 into threaded holes 89. Gasket 24 is provided between the plate 20 and the bolt ring 88 to seal the canister 22. Contamination of the surrounding environment by leakage of oil from the chamber 46 in the piston and cylinder assembly 34 is controlled by a series of sealed chambers 75 and 19. The secondary oil containment chamber 75 is formed within cylinder 73 to capture any oil that seeps from primary oil pressure chamber 46 through the two seals 52, 54. The chamber 75 is sealed by means of a double lip seal 55 provided between cylinder 40 and cylinder 73 and the plastic seal or O-ring provided between the snap ring 78 and the flange 74 at the end of cylinder 73. A tertiary chamber 19 within the housing 18 is sealed by means of the gasket 24 provided between plate 20 and ring 88 the seal 95, and a plastic or O-ring seal provided between snap ring 44 and opening 42. The sealed chambers 19 and 75 also prevent contamination of the oil in chamber 46 from foreign matters in the surrounding environment.
The piston 50 is connected to the lever arm 12 for the brake by means of the rod 26 which is axially aligned in the bore 56 of piston 50. The rod 26 includes a head 98 at the inner end. The rod is retained in the chamber 60 by means of a split spherical member or plug 100 that is mounted on the rod below the head 98 and forms a ball joint in connection with the spherical seat 62 in the end of the piston 50. With this arrangement the rod 26 is free to rotate or pivot with respect to the piston 50. In this regard it should be noted that the rod is connected to lever 12 for the brake. The arc of travel of the connection of the piston to the lever arm 12 as seen in FIG. 1 causes the rod to pivot with respect to the piston 50. With this arrangement and considering the ball joint location far from the threaded end, the rod 26 will not introduce any significant side load forces on the piston 50.
In operation, the cylinder 40 is pressurized when the fluid system is pressurized. The piston 50 will be forced toward the end of the chamber 46 and the rod 26 will push the lever arm 12 to a position to open or release the brake. As the rod 26 moves outwardly, it is free to pivot on the special seat 62 to compensate for any misalignment of the rod 26 with respect to the lever 12.
In the event of a loss of hydraulic pressure in the system (FIG. 5), the springs 82 and 84 will force the piston 50 toward the open end of the chamber 46 in the cylinder 40. Fluid in the cylinder will be forced out of the chamber 46 through the opening 48. The return motion of the piston 50 will rotate the lever arm 12 to set the brake as shown in phantom in FIG. 1. The spring force of the compressed springs 82 and 84 must be sufficient to discharge the fluid from chamber 46 in cylinder 40 almost instantaneously.
If it is desired to release the brake on loss of pressure, the rod 26 can be manually disconnected from the connector 30. This can be accomplished by providing a flat section 107 on each side of the rod 26 adjacent to the threaded end of the rod 26. The rod can be unscrewed from the connector 30 by engaging the flats 107 with a wrench to turn the rod. This is of particular importance if there is a loss of pressure in an off road vehicle. If the brake cannot be released, the vehicle could not be moved for repair or replacement of parts.
Thus, it should be apparent that there has been provided in accordance with the present invention a spring applied/pressure release emergency brake actuator that fully satisfies the aims and advantages set forth above. Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.
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An apparatus for actuating an emergency brake on loss of fluid pressure in a brake system, the apparatus including a housing for one or more compression springs, a piston and cylinder assembly mounted in the housing and being operatively connected to the fluid system and to the emergency brake to release the brake on sensing brake system fluid pressure and to apply the brake on loss of system pressure in the brake system, the spring or springs being permanently housed in the housing in a precompressed condition so that the piston and cylinder assembly can be removed from the housing without releasing the springs.
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[0001] This invention was made with U.S. Government support under contract number N00019-02-C-3003 awarded by the United States Navy, and the U.S. Government may have certain rights in the invention.
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0002] The present application is related to the following copending applications filed on the same day as this application: “RACK AND PINION VARIABLE VANE SYNCHRONIZING MECHANISM FOR INNER DIAMETER VANE SHROUD” by inventors J. Giaimo and J. Tirone III (attorney docket number U73.12-002); “SYNCH RING VARIABLE VANE SYNCHRONIZING MECHANISM FOR INNER DIAMETER VANE SHROUD” by inventors J. Giaimo and J. Tirone III (attorney docket number U73.12-003); “GEAR TRAIN VARIABLE VANE SYNCHRONIZING MECHANISM FOR INNER DIAMETER VANE SHROUD” by inventors J. Giaimo and J. Tirone III (attorney docket number U73.12-004); and “INNER DIAMETER VARIABLE VANE ACTUATION MECHANISM” by inventors J. Giaimo and J. Tirone III (attorney docket number U73.12-005). All of these applications are incorporated herein by this reference.
BACKGROUND OF THE INVENTION
[0003] This invention relates generally to gas turbine engines and more particularly to vane shrouds for use in such engines.
[0004] Gas turbine engines operate by combusting a fuel source in compressed air to create heated gases with increased pressure and density. The heated gases are ultimately forced through an exhaust nozzle, which is used to step up the velocity of the exiting gases and in-turn produce thrust for driving an aircraft. The heated gases are also used to drive a turbine for rotating a fan to provide air to a compressor section of the gas turbine engine. Additionally, the heated gases are used to drive a turbine for driving rotor blades inside the compressor section, which provides the compressed air used during combustion. The compressor section of a gas turbine engine typically comprises a series of rotor blade and stator vane stages. At each stage, rotating rotor blades push air past the stationary stator vanes. Each rotor/stator stage increases the pressure and density of the air. Stators serve two purposes: they convert the kinetic energy of the air into pressure, and they redirect the trajectory of the air coming off the rotors for flow into the next compressor stage.
[0005] The speed range of an aircraft powered by a gas turbine engine is directly related to the level of air pressure generated in the compressor section. For different aircraft speeds, the velocity of the airflow through the gas turbine engine varies. Thus, the incidence of the air onto rotor blades of subsequent compressor stages differs at different aircraft speeds. One way of achieving more efficient performance of the gas turbine engine over the entire speed range, especially at high speed/high pressure ranges, is to use variable stator vanes which can optimize the incidence of the airflow onto subsequent compressor stage rotors.
[0006] Variable stator vanes are typically circumferentially arranged between an outer diameter fan case and an inner diameter vane shroud. In split shroud designs, the vane shroud is divided into a forward and aft component, with inner diameter ends of the variable stator vanes secured between the two components. Traditionally, the forward and aft components of the inner diameter vane shroud have been fabricated from solid metal pieces. These solid metal vane shrouds are typically used in ground test engines where weight is not a concern. However, these solid vane shrouds are not suitable for use in production engines used in aircraft where weight is of the utmost concern. Thus, there is a need for a flight-weight inner diameter variable vane shroud.
BRIEF SUMMARY OF THE INVENTION
[0007] The present invention is directed toward an inner diameter vane shroud for receiving inner diameter ends of stator vanes in a turbine engine. The inner diameter vane shroud includes a forward shroud component and an aft shroud component. The forward shroud component has a defined length and includes a forward hollow channel running the length of the forward shroud component. The aft shroud component has a defined length and includes an aft hollow channel running the length of the aft shroud component.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 shows a partially cut away front view of a stator vane section of a gas turbine engine in which the present invention is used.
[0009] FIG. 2 shows a close up of a stator vane array positioned between a fan case and the inner diameter vane shroud of the present invention.
[0010] FIG. 3A shows section 3 - 3 of FIG. 2 showing a cross section of the inner diameter vane shroud between the vane sockets.
[0011] FIG. 3B shows an exploded view of the cross section of the inner diameter vane shroud of FIG. 3A .
[0012] FIG. 4A shows section 4 - 4 of FIG. 2 showing a cross section of the inner diameter vane shroud at the vane sockets.
[0013] FIG. 4B shows an exploded view of the cross section of the inner diameter vane shroud of FIG. 4A .
DETAILED DESCRIPTION
[0014] FIG. 1 shows a partially cut away front view of stator vane section 10 of a gas turbine engine in which the present invention is used. Stator vane section 10 comprises fan case 12 , vane shroud 14 , variable vane array 16 and actuator 18 . Vane shroud 14 is comprised of forward vane shroud component 20 and aft vane shroud component 22 , which form inner diameter vane sockets 24 . A half-socket, or a recess, is located on each of forward shroud portion 20 and aft shroud portion 22 to form socket 24 . In FIG. 1 , only a portion of forward vane shroud 20 is shown so that the interior of sockets 24 can be seen. Inner diameter vane shroud 14 can be constructed in component sizes less than the entire circumference of inner diameter vane shroud. In one embodiment, as shown in FIG. 1 , forward vane shroud component 20 is made of sections approximately one sixth (i.e. 60°) of the circumference of inner diameter vane shroud 14 , and aft shroud component 22 is made of sections one half (i.e. 180°) the circumference of inner diameter vane shroud 14 .
[0015] Variable vane array 16 is comprised of drive vanes 26 and a plurality of follower vanes 28 . Drive vanes 26 and follower vanes 28 are connected inside inner diameter vane shroud 14 by a synchronizing mechanism such as described in the copending related applications referred to above. Thus, when actuator 18 rotates drive vanes 26 , follower vanes 28 rotate a like amount.
[0016] Typically, follower vanes 28 encircle the entirety of vane shroud 14 . Only a portion of variable vane array 16 is shown so that sockets 24 can be seen. Drive vanes 26 and follower vanes 28 are rotatably mounted at the outer diameter of stator vane section 10 in fan case 12 , and at the inner diameter of stator vane section 10 in vane shroud 14 . The number of drive vanes 26 varies in other embodiments and can be as few as one. In one embodiment, variable vane array 16 includes fifty-two follower vanes 28 and two drive vanes 26 . Drive vanes 26 are similar in construction to follower vanes 28 . In one embodiment, drive vanes 26 are of heavy duty construction to withstand forces applied by actuator 18 .
[0017] Stator vane section 10 is typically located in a compressor section of a gas turbine engine downstream of, or behind, a rotor blade section. Air is forced into stator vane section 10 by a preceding rotor blade section or by a fan. The air that passes through stator vane section 10 typically passes on to an additional rotor blade section. Drive vanes 26 and follower vanes 28 rotate along their respective radial positions in order to control the flow of air through the compressor section of the gas turbine engine.
[0018] FIG. 2 shows a close up of variable vane array 16 between fan case 12 and vane shroud 14 . Drive vanes 26 and follower vanes 28 are rotatable in sockets 24 of inner diameter vane shroud 14 . Section 3 - 3 is taken at a position along inner diameter vane shroud 14 between sockets 24 . Between sockets 24 , forward shroud component 20 and aft shroud component 22 are fastened together to form inner diameter vane shroud 14 . Section 44 is taken at a position along inner diameter vane shroud 14 where inner diameter end of follower vane 28 A is inserted in socket 24 A. Forward shroud component 20 and aft shroud component 22 come together to form sockets 24 for securing the inner ends of variable vane array 16 .
[0019] FIG. 3A shows section 3 - 3 of FIG. 2 showing a cross section of inner diameter vane shroud 14 between vane sockets 24 . FIG. 3B shows an exploded view of the cross section of the inner diameter vane shroud of FIG. 3A . FIGS. 3A and 3B will be discussed concurrently. Inner diameter vane shroud 14 includes forward shroud component 20 , aft shroud component 22 , forward hollow region 30 , aft hollow region 32 , hole 34 , fastener 36 , locking insert 37 , opening 38 , cap 39 , recess 40 and hole 42 .
[0020] Forward hollow region 30 and aft hollow region 32 are formed during the manufacture of forward vane shroud component 20 and aft vane shroud component 22 using investment casting techniques known in the art. In one embodiment, ceramic cores are placed in the mold during the casting of forward shroud component 20 and aft shroud component 22 . The ceramic cores are removed after molds of forward vane shroud component 20 and aft vane shroud component 22 have solidified and cooled in order to create forward hollow region 30 and aft hollow region 32 , respectively. Forward hollow region 30 and aft hollow region 32 reduce the amount of material required to produce forward shroud component 20 and aft shroud component 22 thereby reducing the weight of inner diameter vane shroud 14 . Inner diameter vane shroud 14 remains sturdy enough to secure drive vanes 26 and follower vanes 28 during operation of a gas turbine engine. Lightweight cast forward shroud component 20 and aft shroud component 22 are also capable of being machined to meet the design requirements of the stator vanes and gas turbine engine with which they are to be used.
[0021] Forward vane shroud component 20 is cast with opening 38 , which provides access to forward hollow region 30 . In other embodiments, opening 38 can be produced with machining procedures after casting. Additional features of forward vane shroud component 20 are machined into forward vane shroud component 20 after casting. For example, recess 40 can be machined into forward shroud component 20 and aft shroud component 22 as a weight reduction measure. Hole 34 and hole 42 can be produced with additional machining steps. The exact shape and form of hole 34 and recess 40 depend on specific design requirements of gas turbine engine in which inner diameter vane shroud 14 will be used. Forward vane shroud component 20 and aft vane shroud component 22 can be made in segments less than entire circumference of the final required inner diameter vane shroud 14 . In one embodiment, forward vane shroud component 20 is comprised of approximately one sixth circle (i.e. 60°) segments and aft vane shroud component 22 is comprised of approximately half circle (i.e. 180°) segments for use in split fan case designs.
[0022] Inner diameter vane shroud 14 is assembled by securing forward shroud component 20 to aft shroud component 22 with fastener 36 . Locking insert 37 is placed inside hole 34 across from hole 42 . Fastener 36 is inserted through forward hollow region 30 , through hole 42 and into locking insert 37 of hole 34 . Cap 39 is placed over opening 38 to close it off and provide an aerodynamic surface to the front of forward vane shroud component 20 . Drive vanes 26 and follower vanes 28 are inserted into sockets 24 before assembly of forward shroud component 20 and aft shroud component 22 .
[0023] FIG. 4A shows section 4 - 4 of FIG. 2 showing a cross section of inner diameter vane shroud 14 at vane sockets 24 . FIG. 4B shows an exploded view of the cross section of the inner diameter vane shroud of FIG. 4A . FIGS. 4A and 4B will be discussed concurrently. Inner diameter vane shroud 14 includes forward shroud component 20 , aft shroud component 22 , socket 24 A, forward hollow region 30 , aft hollow region 32 , recess 33 , opening 38 , and cap 39 . Follower vane 28 A includes trunnion 43 , which is pivotably located in socket 24 A of inner diameter vane shroud 14 . Socket 24 A is comprised of recess 25 A and recess 25 B. Forward vane shroud component 20 and aft vane shroud component 22 come together to form socket 24 A when forward vane shroud component 20 is secured to aft vane shroud component 22 using fastener 36 as shown in FIG. 3A . Socket 24 A is shaped to have a profile for accepting the profile of trunnion 42 . Thus, trunnion 43 is secured in socket 24 A and able to rotate in socket 24 A. Recess 33 is molded directly into or machined into aft shroud component 22 as a weight reduction measure.
[0024] Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
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An inner diameter vane shroud for use in a gas turbine engine is comprised of lightweight cast forward and aft shroud components. The forward and aft shroud components are made with an investment casting technique that creates a hollow cavity that runs in a circumferential direction through each component. The forward and aft shroud components are matable to form sockets that receive inner diameter ends of variable stator vanes.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of International Application Serial No. PCT/AU03/00868, filed Jul. 4, 2003.
FIELD OF THE INVENTION
[0002] The present invention relates to a delivery system and composition. More particularly, the delivery system and composition of the present invention are intended for use in the delivery or administration of micro-organisms, including but not limited to, the improved delivery of plant growth promoting rhizobacteria to plants, the inoculation of legumes with root nodule bacteria (e.g. Rhizobium, Bradyrhizobium, Mesorhizobium etc) to stimulate root nodule formation and to allow improved capacity for storage prior to use.
DESCRIPTION OF THE BACKGROUND ART
[0003] There is active research throughout the world aiming to develop growth-promoting or disease protection from micro-organisms applied to agricultural crops. The focus of much of this research is to decrease reliance on chemical application e.g. fertilisers and particularly those that supply nitrogen and phosphorous, and other chemicals associated with disease protection (e.g. fungicides).
[0004] The range of growth-promoting micro-organisms known to exert beneficial effects on crop plants are often collectively referred to as Plant Growth Promoting Rhizobacteria (“PGPR”). The term Rhizobacteria refers to micro-organisms inhabiting the rhizosphere , a layer of soil surrounding plant roots that typically has a high level of microbial activity.
[0005] PGPR may enhance plant growth by both direct and indirect means, many of which are not well understood. Examples of direct means include synthesis of phytohormones that stimulate root development, fixation of atmospheric nitrogen, solubilization of phosphate and the enhancing of nutrient uptake. The fixation of atmospheric nitrogen is achieved by a range of soil bacteria, including nitrogen fixing root module bacteria ( Rhizobium and Bradyrhizobium , there are now other genera described, e.g. Mesorhizobium, Sinorhizobium, Methylobacterium etc.), free living nitrogen-fixing bacteria (e.g. Azotobacter and Azosprillum ) and endophytic nitrogen-fixing bacteria ( Gluconobacter diazotrophicus ), collectively referred to as Biological Nitrogen Fixers (“BNFs”).
[0006] Indirect means of plant growth enhancement may include the suppression of the growth of plant pathogens by way of production of antibiotics, siderophores, extracellular enzymes, or by way of the induction of systemic resistance. These means have also been referred to as biologic control. Strains of bacteria identified as potential biocontrol agents include species of Bacillus, Pseudomonas, Burkholderia, Eterobacter and Serratia.
[0007] As an example, it is common practice to inoculate leguminous plants with bacterial cultures of the genus rhizobia so that the bacteria will form colonies in nodules within the roots of the legume and fix nitrogen. Rhizobial strains are generally mixed with a carrier to ensure long term storage (but conventional methods have meant long term storage is best achieved under refrigeration) and ease of handling. A large range of substances have been used as carriers including soils, peat, charcoal and lignite.
[0008] The known techniques of inoculation include mixing a moist culture of bacteria with a pulverulent carrier. The carrier maintains the bacteria in a moist state whilst giving the total mass the powdery character desired for mixing with seeds.
[0009] For rhizobia , embedding cells in a carrier of sterile peat was developed in the 1950s. This methodology remains as commercial best practice today. Nevertheless, it is limited to the application of peat-carrier onto seed. Ideally, seed should be sown into moist soil soon after inoculation. Even under optimal conditions, the death rate of cells on seed can be as high as 90% per day, primarily because of desiccation.
[0010] Desiccation is the main factor impacting on rhizobial survival. There is variation in tolerance to different levels of humidity between strains of rhizobia . The rate cells are dried plays an important role in survival, with better survival after slow drying. Slow rehydration also results in better survival. The greater susceptibility of fast-growing rhizobia to desiccation than slow-growing strains has been attributed to their greater retention of water.
[0011] Under ideal conditions, the use of peat-based carriers for delivery of rhizobial bacteria to legumes has been relatively effective. Most of Australia's agricultural legumes have been inoculated in this manner for the last 50 years, with varying success. However, there have been biological and economic pressures upon farming in the last decade and these factors have necessitated changes in farming practice. A good example of the biological pressures is best exemplified by the build-up of plant pathogens. For the major Australian pulse crops lupin, chickpea, fababean and field pea, disease pressure is such that all crops are recommended to be sown with seed-applied fungicides. This presents a management conundrum, as fungicides are detrimental to the survival of rhizobia when the two are in close contact or mixed together.
[0012] The economic pressures upon farmers have dictated that yields must be maximised, as yield is the greatest determinant of profitability. In dryland cropping, a means to achieve this is through sowing the crop prior to winter rains to maximise water-use efficiency. Weeds are controlled post-sowing, however the rapid death of rhizobia on seed sown into dry soil precludes the dry-sowing option for many crops and pastures. Inoculants on seeds generally also suffer a high mortality rate under this regime. Further complications occur in seasons when early winter rains encourage the sowing of crops, but are not followed by sufficient rains to keep the soil moist. Strategies to regulate water and oxygen gain or loss from rhizobia coated onto seed and how to separate inoculants from toxic chemicals, has posed a challenging research problem.
[0013] Current inoculation technology is sub-optimal and legume performance often suffers due to poor nodulation, especially following extended periods of dry, warm weather before adequate rainfall is received. The composition of the current invention is at least in part intended to alleviate this limitation and enable a far more effective rhizobial inoculation.
[0014] There is a need for a more favourable and long term storage option for all PGPR, including rhizobial cells. A key attribute of the delivery system and composition of the present invention is its suitability for farming in Mediterranean climates (wet winter, dry summer). In the case of pasture improvement by sowing legumes, farmers have a strong desire to dry sow (i.e. before the winter rainfall commences). On many large farms this is purely a logistical decision due to time restrictions once winter rainfall commences, although there are also economic advantages (e.g. pastures commence growing as soon as rain falls, thus greater yield).
[0015] The problems associated with the inoculation of leguminous plants with rhizobia , detailed above, are clearly applicable to the broader group of PGPRs, particularly with regard to the need to allow long term storage and/or early application to crops, whilst maintaining viability of the micro-organisms being so applied.
[0016] Similarly, there are further applications in which it is desirable to deliver micro-organisms in a form or manner that maintains viability during and subsequent to administration, but also allows viable storage prior to administration. Such further applications may include mining or mineral processing applications, and also both medical and veterinary applications. For example, the bacterial leaching of ores and concentrates, in any of tanks, vats, heaps or dumps may benefit from an efficient delivery system of viable micro-organisms.
[0017] The present invention has as one object thereof to overcome substantially, or at least provide a useful alternative to, the above-mentioned problems associated with the prior art.
[0018] The preceding discussion of the background to the invention is intended to facilitate an understanding of the present invention. However, it should be appreciated that the discussion is not an acknowledgement that any material referred to was part of the common general knowledge in Australia as at the priority date of the application.
[0019] Throughout the specification, unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.
SUMMARY OF THE INVENTION
[0020] In accordance with the present invention there is provided a delivery system for the administration of micro-organisms, the delivery system comprising at least one species of micro-organism, water and an aluminosilicate clay, wherein the aluminosilicate clay comprises at least one of calcium bentonite and saponite.
[0021] Preferably, the delivery system further comprises a food source that also provides a protective envelope for the micro-organisms. The food source preferably comprises organic acids in the form of peat.
[0022] In one form of the invention the or each micro-organism is chosen for a beneficial effect it may exert, directly or indirectly, for the purpose of one or more of plant growth promotion, mineral processing, medical or veterinary applications.
[0023] In an advantageous form of the present invention the micro-organisms comprise at least in part one or more PGPR and even more advantageously, the micro-organisms comprise at least in part one or more rhizobial bacteria.
[0024] In accordance with the present invention there is further provided a inoculant composition comprising at least one species of micro-organism, water and an aluminosilicate clay, wherein the aluminosilicate clay comprises at least one of calcium bentonite and saponite.
[0025] Preferably, the composition comprises said aluminosilicate clay to which said micro-organisms and water have been added. The composition may further advantageously comprise peat.
[0026] The peat and the micro-organisms may be provided in the form of a peat-based inoculant. The peat is preferably provided in a proportion of between about 0.1 to 50% by weight of the inoculant composition.
[0027] It should be understood that the ratio of peat may vary with the type of microbial strains utilised. For some strains the ratio of peat to clay may be 1:10, some it will be 1:20 and some it will be 1:40.
[0028] The clay preferably comprises aggregate particle sizes ranging between about 0.2 and 10 mm in diameter. Still preferably, the clay comprises aggregate particle sizes ranging between about 0.5 and 2 mm in diameter.
[0029] The clay is preferably provided in a proportion of between about 50 to 99.9% by weight of the composition. Further preferably, the clay is provided in a proportion of between about 75 to 99.9% by weight of the composition.
[0030] Preferably, the micro-organism is specific to a plant to be inoculated.
[0031] Preferably, the composition is provided in the form of granules. The size of the granules are preferably either similar to or smaller than the plant seeds to be inoculated. The granules are still preferably between about 0.1 to 5 mm in diameter. The granules are yet still preferably between about 0.1 to 2 mm in diameter.
[0032] In one form of the invention the composition is provided in the form of a mixture comprising:
a first portion of granules sized approximately the same size as plant seeds to be inoculated; and a second portion of particulate matter more finely divided than the granules of the first portion.
[0035] The first portion of granules are preferably between about 0.1 to 5 mm in diameter. The second portion of particulate matter preferably has a size of less than about 0.1 mm.
[0036] Preferably, the inoculant comprises between about 2 and 20% water. Still preferably, the inoculant comprises between about 5 and 15% water. Still further preferably, the inoculant comprises between about 6 and 9% water. During storage of the inoculant composition, the water concentration may decrease depending on storage conditions and humidity.
[0037] In an advantageous form of the present invention the micro-organisms comprise at least in part one or more PGPR and even more advantageously, the micro-organisms comprise at least in part one or more rhizobial bacteria.
[0038] It should be understood that the ratio of peat may vary with the type of rhizobial strain utilised. For some strains the ratio of peat to clay may be 1:10, some it will be 1:20 and some it will be 1:40.
[0039] The legume may be any crop, pasture, tree or fodder legume used in an agricultural situation or tropical legumes and may be selected from the group comprising clover, lupins, serradella, biserrula, medics, chickpea, fababean, lentil, beans, peanuts, field pea, burgundy bean, any bean, French or common bean, Vigna spp, Centrosema spp, Desmodium spp, Desmanthus spp, Stylosanthes spp, Leucana spp and the like. The inoculant of the present invention has substantial application with respect to tropical legumes, where high temperatures and more rapid desiccation impacts even more severely on rhizobial survival compared with the Mediterranean style winter sown legumes.
[0040] For pasture legumes, the size of the granules of the rhizobial inoculant may be either similar or smaller than the legume seeds, ranging between about 0.1 and 5 mm, but most preferably between about 0.1 and 2 mm. In the case of crop and pulse legumes, the rhizobial inoculant granules are preferably between about 0.1 and 5 mm (most preferably between about 0.1 and 2 mm) which is preferably smaller than the legume seeds.
[0041] In providing granules of similar but smaller size to the seed to be inoculated, mixing and uniformity of ‘flow’ through seeding machinery is facilitated leading to enhanced distribution of seed and granules in the sown crop or pasture. Further, the very fine granules are able to adhere to the surface of the legume seed being sown, thus providing greater proximity between the seed and the inoculant source leading to more rapid formation of functional nodules when the plant germinates and commences growing.
[0042] The ratios of the first portion of granules and the second portion of granules is dependant on factors such as seed type, water content of the inoculant and sowing rates. Smaller granules are better adapted to adhere to seed surfaces and provide better distribution in sown rows, although higher proportion of finer granules, whilst potentially leading to more rapid rates of nodulation, create greater handling problems when sowing. The larger granules more easily facilitate movement through agricultural machinery.
[0043] It is preferable for the inoculant to contain an amount of water sufficient to maintain the rhizobial cells in a viable state. If the water content is too high, logistical problems are encountered in the sowing of the granules with legume seeds.
[0044] The inoculant composition of the present invention may further comprise a fungicide, fungal spores or additional growth promoting bacteria.
[0045] In accordance with the present invention there is further provided a method for the preparation of a delivery system, the method characterised by the method steps of:
a) blending the components micro-organisms, water and an aluminosilicate clay comprising at least one of calcium bentonite and saponite to form a slurry; and b) drying the slurry.
[0048] The method preferably further includes the step of:
a) blending peat with the slurry.
[0050] In accordance with the present invention there is yet still further provided a method for the preparation of a delivery system, the method characterised by the method steps of:
a) blending the components peat, micro-organisms and water to form a slurry; b) incubating the slurry to increase bacteria numbers; c) adding an aluminosilicate clay comprising at least one of calcium bentonite and saponite to the slurry; and d) drying the slurry.
[0055] The incubation step preferably further includes the steps of:
i) adding a carbon source; and ii) agitating the slurry in a sterile environment.
[0058] The carbon source is preferably provided in the form of sucrose, glucose, brewery waste and the like. Preferably, the carbon source is added at a concentration of between about 1 to 5% by weight.
[0059] The slurry is preferably agitated for between about 48 and 96 hours.
[0060] In accordance with the present invention there is further provided a method for the preparation of a delivery system, the method characterised by the method steps of:
a) incubating a culture of at least one micro-organism in water to increase numbers thereof; b) adding an aluminosilicate clay comprising at least one of calcium bentonite and saponite to the culture to form a slurry; and c) drying the slurry.
[0064] Preferably, the culture is incubated for between about 24 and 72 hours.
[0065] The method preferably further comprises the additional step of:
agitating the culture of step a).
[0067] Preferably, the culture is agitated for between about 24 to 48 hours.
[0068] The method preferably further includes the step of:
adding peat to the culture of step a).
[0070] The peat and micro-organisms are preferably provided in the form of a peat-based inoculant. The peat-based inoculant is preferably stored in a fridge prior to use and is warmed to room temperature prior to blending.
[0071] Preferably, water comprises between about 10 to 90% of the total mass of peat and aluminosilicate clay in the slurry. The water still preferably comprises between about 30 to 80% of the total mass of peat and aluminosilicate clay in the slurry. The water yet still preferably comprises between about 55 to 75% of the total mass of peat and aluminosilicate clay in the slurry.
[0072] The method preferably further includes the step of:
allowing the slurry to stand prior to drying.
[0074] The slurry may be air dried, oven dried or vacuum dried. Preferably, the slurry is air dried in a batch or continuous process. The air drying may preferably performed at about 20° C. for between about 24 and 120 hours.
[0075] The depth of slurry in the batch is preferably maintained between about 2 cm to 4 cm. The depth of slurry in the batch is still preferably maintained between about 2 cm to 3 cm.
[0076] The method may further include the step of:
milling the composition to provide granules.
[0078] In an advantageous form of the present invention the micro-organisms comprise at least in part one or more PGPR and even more advantageously, the micro-organisms comprise at least in part one or more rhizobial bacteria.
[0079] In accordance with the present invention there is provided a method of inoculation of legumes, the method characterised by the method steps of:
a) mixing granules of rhizobial inoculant as described above with legume seeds or with fertiliser sown with legumes seeds; and b) sowing the mixture.
[0082] The mixture may preferably be sown prior to winter rains.
[0083] Preferably, the legume seed is sown at rates between about 1 and 150 kg/ha, with most preferably, the rate of granular inoculants between about 5 and 20 kg/ha.
[0084] The method may further include the step of:
adding fertiliser to the mixture.
[0086] In one form of the invention, the method further includes the step of:
applying a fungicide to a legume seed prior to mixing the seed with the granules.
BRIEF DESCRIPTION OF THE DRAWINGS
[0088] The present invention will now be described, by way of example only, with reference to three embodiments thereof and the accompanying Figures, in which:—
[0089] FIG. 1 is a plot showing nodule score of vicia faba plants inoculated with inoculant composition in accordance with a first embodiment of the present invention, inoculated with conventional peat based inoculant and vicia faba plants without inoculation;
[0090] FIG. 2 is a plot showing nodule score of lentils inoculated with inoculant composition in accordance with the first embodiment, inoculated with conventional peat based inoculant and lentils without inoculation;
[0091] FIG. 3 is a plot showing nodule score of lentils inoculated with inoculant composition in accordance with the first embodiment, inoculated with conventional peat based inoculant and lentils without inoculation;
[0092] FIG. 4 is a plot showing nodule score of lentils inoculated with inoculant composition in accordance with the first embodiment, lentils inoculated with granules in accordance with the first embodiment and stored in an environment of varying temperatures, inoculated with conventional peat based inoculant and lentils without inoculation; and
[0093] FIG. 5 is a plot showing the results of field tests on the inoculation of field peas with ( Pisum sativum ) inoculated with inoculant composition in accordance with a second embodiment of the present invention, field peas inoculated with commercially available peat based inoculants, field peas inoculated with clay and uninoculated field peas.
DETAILED DESCRIPTION OF THE INVENTION
[0094] Three embodiments of the present invention will now be described with reference to a delivery system and composition for rhizobial inoculation. It is to be understood that these embodiments are detailed by way of example and are not to be considered limiting.
[0095] In a first embodiment of the present invention, water (67% of total mass of clay), at 20° C. was added to a strain of commercially available peat-based inoculant (0.1 to 50% by weight of the rhizobial inoculant composition. For trials, ratios of 1:10, 1:20 and 1:40 of peat based inoculant to clay were used. See specific examples for ratios used.). The peat based inoculant had been stored in a fridge and was allowed to warm to room temperature before use. The composition was stirred thoroughly and was left to stand for 15 min at 20° C.
[0096] A calcium bentonite or saponite clay (90% by weight of the rhizobial inoculant composition for the 1:10 composition described above) that had been milled to aggregate particle size of less than about 2 mm was added and the slurry stirred for 15 min. The clay had been air dried to a water content of about 6 to 10% by weight.
[0097] The slurry was air dried at 20° C. for between 24 hr and 120 hr depending on the batch size. Once the composition was dried sufficiently, it was crushed and milled The moisture content of the composition prior to crushing and milling was about 10%.
[0098] In a second embodiment of the present invention, water (67% of total mass of clay), at 20° C. was added to a strain of commercially available peat based inoculant (0.1 to 50% by weight of the rhizobial inoculant composition. For trials, ratios of 1:10, 1:20 and 1:40 of peat based inoculant to clay were used. See specific examples for ratios used.). The peat based inoculant had been stored in a fridge and was allowed to warm to room temperature before use. The composition was stirred thoroughly and was left to stand for 15 min at 20° C.
[0099] A carbon source in the form of sucrose, glucose or brewery waste was added at a concentration of between about 0.5 to 5% by weight and the mixture agitated under sterile conditions for between 48 and 96 hours.
[0100] A calcium bentonite or saponite clay (90% by weight of the rhizobial inoculant composition for the 1:10 composition described above) that had been milled to aggregate particle size of less than about 2 mm was added and the slurry stirred for 15 min. The clay had been air dried to a water content of about 6 to 10% by weight.
[0101] The slurry was air dried at 20° C. for between 24 hr and 120 hr depending on the batch size. Once the composition was dried sufficiently, it was crushed and milled. The moisture content of the composition prior to crushing and milling was about 10%.
[0102] In a third embodiment of the present invention, a culture of rhizobial bacteria was fermented in water (or other typical nutrient broths for growing bacteria) with sucrose or other food source for between about 24 to 72 hours to increase cell numbers, after which time sterile peat was added and the culture agitated for between about 24 to 48 hours. Clay was then added to the mixture in the manner described above.
[0103] Test results show equivalent cells per g dry bentonite can be achieved (Table 1).
TABLE 1 Bacteria cell numbers of commercial peat and culture prepared by the method of the invention. Manufacture system 0 hrs 72 hrs 120 hrs 168 hrs Culture added to sterile 2.95E+08 2.81E+08 4.02E+07 2.66E+07 peat Commercial Peat 9.30E+07 1.86E+07 1.17E+07 1.19E+07
[0104] The three embodiments described above are three methods that produce an inoculant suitable for the inoculation of legumes. The bacteria are selected based on the intended species of legume to be inoculated. The following examples utilise inoculants produced according to the first embodiment utilising rhizobial bacteria specific to the legume being sown. Granules of the composition of the first embodiment were mixed with legume seeds and the mixture sown. It is believed that when the plants grow, their roots intercept inoculant granules that are in close proximity to the emerging seedling and the rhizobial cells they contain enable the nodulation process. In the absence of other limiting factors (e.g. nutrition and water supply) the effectiveness of nodulation in legumes can be assessed by dry matter production (i.e. larger plants have better nodulation). Visual observations of the roots of the plant reported in Tables 2, 3 and 4 confirm this with more widespread nodulation and greater nodule numbers than ‘conventionally’ inoculated legumes.
EXAMPLE 1
[0105] Dry matter of 9 weeks old plants of Biserrula ( Biserrula pelecinus ) inoculated with granules of inoculant of the present invention manufactured using ratios of peat to clay (1:1, 1:10 and 1:100) was equivalent or better than conventionally inoculated biserrula as seen in Table 2. There is no chance of contamination affecting the trials as the rhizobial strain for Biserrula pelecinus is unique. (i.e. no other legumes can use this strain of bacteria and no other natural strain can be used by Biserrula. Biserrula is a monotypic genus (single species)).
TABLE 2 Dry matter yield (g) of biserrula (cv Casbah) grown for 9 weeks. Dry matter yield (g/pot) of Casbah inoculated with clay based granules different ratios of clay:peat, compared with conventional inoculation. Conventional 1:1 granule 1:10 granule 1:100 granule inoculation g g g g Rep 1 0.698 0.473 0.539 0.456 Rep 2 0.807 0.811 0.655 0.518 Rep 3 0.556 0.630 0.645 0.584 Rep 4 0.710 0.685 0.559 0.473 Mean 0.693 0.650 0.600 0.508 Std err 0.052 0.070 0.030 0.029
[0106] Inoculant source for both granule production and conventional inoculation was WSM 1497, biserrula special. Uninoculated controls were used in the experiment to provide extremes of plant performance for comparison (data are not reported because the plants died 3 weeks after sowing from lack of nitrogen supply).
EXAMPLE 2
[0107] Storage of manufactured granules at temperatures fluctuating between 60° C. (day) and 15° C. (night) for 2 weeks (simulation of an average summer day) did not impact on dry matter yield of biserrula (cv Casbah ) inoculated with granules of rhizobial inoculant as seen in Table 3. Trials did not include peat treated under similar conditions as it is known that the rhizobium is not able to survive at temperatures over 5° C. under these conditions.
TABLE 3 Impact of high temperature fluctuation (60/15° C.) on granules stored for 2 weeks prior to sowing biserrula (cv Casbah) grown for 7 weeks. Dry matter yield (g) of biserrula (cv Casbah) grown for 7 weeks. Conventional inoculation prior 1:1 granule 1:10 granule 1:100 granule to sowing g g g g Rep 1 0.075 0.103 0.079 0.101 Rep 2 0.054 0.110 0.075 0.100 Rep 3 0.053 0.072 0.070 0.095 Rep 4 0.068 0.079 0.028 0.097 Mean 0.063 0.091 0.063 0.098 Std err 0.005 0.009 0.012 0.001
EXAMPLE 3
[0108] Granules manufactured with different ratios of water were able to cope with extreme temperatures fluctuating between 60° C. (day) and 15° C. (night) for 4 weeks as seen in Table 4. Storage for 4 weeks under this harsh regime did not impact on dry matter yield of Casbah biserrula inoculated with granules subjected to these conditions.
[0109] Without being limited by theory, it is proposed that the cell numbers surviving in the inoculant granules at the time of nodulation are greater than pure peat (the commercial carrier) on the surface of conventionally inoculated legumes. The organic acids in the peat supply a food source and enable multiplication and subsequent survival. This does not happen in peat alone (due to lack of sufficient moisture and space).
TABLE 4 Impact of high temperature fluctuation (60/15° C.) on granules produced using variable water contents and stored for 4 weeks prior to sowing biserrula (cv Casbah) grown for 4 weeks. Dry matter yield (g) of biserrula (cv Casbah) grown for 4 weeks. Conventional 1:1 granule 1:1 granule 1:1 granule inoculation prior 33% water 50% water 66% water to sowing g g g g Rep 1 0.014 0.031 0.019 0.020 Rep 2 0.017 0.024 0.021 0.022 Rep 3 0.019 0.026 0.022 0.024 Rep 4 0.013 0.020 0.018 0.021 Mean 0.016 0.025 0.020 0.022 Std err 0.001 0.002 0.001 0.001
EXAMPLE 4
[0110] In a glasshouse experiment, dry matter production of Casbah biserrula plants inoculated with rhizobial inoculant stored at different temperature regimes for 8 weeks (constant 20° C. compared with a fluctuating 60° C./15° C., equivalent to a hot summers day and night) was equivalent to fresh peat inoculation as seen in Table 5.
TABLE 5 Dry matter production of Casbah biserrula grown for four weeks, and inoculated with granules produced and stored under different temperature regimes for 8 weeks prior to sowing biserrula . Treatment Mean St err Nil 0.014 0.005 Fresh Peat 0.061 0.014 60° C./15° C. composition 8 weeks 0.076 0.024 60° C./15° C. composition 8 weeks PD 0.098 0.044 20° C. composition 8 weeks 0.052 0.008
[0111] Plants inoculated with granules subjected to the most severe temperature regime and positionally disadvantaged (i.e. seed and granule separated in pot) were still able to nodulate and produce equivalent biomass (Table 5).
[0112] PD is an acronym for positionally disadvantaged, which in the context of the specification, is intended to mean a process of sowing seeds and granules of the inoculant composition in a pot whereby the seeds and granules are placed as far apart as possible.
EXAMPLE 5
[0113] The results of field experiments shown in FIGS. 1 to 4 used inoculant compositions prepared by the first embodiment. The results shown in FIG. 5 used inoculant composition prepared by the second embodiment. All trials used sowing rates of inoculant composition of 10 kg/ha.
[0114] In a field experiment sown to compare nodulation of Vicia faba either conventionally inoculated (with peat based inoculant) or with rhizobial inoculant of the present invention, there were considerable differences noted in early (6 weeks) nodulation scores, as shown in FIG. 1 . (1:10, 1:20 and 1:40 refer to compositions of the present invention with varying ratios of peat based inoculant to clay). Following sowing, there was an extended dry period, and the conventionally inoculated plants nodulated poorly under this regime. The plants inoculated with granules, were able to source adequate rhizobia from the granules when rainfall did return.
[0115] In a low rainfall environment, lentils inoculated with granules had equivalent nodulation scores to standard peat inoculated plants, and these were all superior to nil inoculation, as can be seen in FIG. 2 .
[0116] Effective legume growth is reliant on early nodulation and nitrogen fixation. Some plants (e.g. lupins that have evolved on sandy soils), are still capable of nodulating later in the season when they have exploited soil nitrogen. Early nodulation of lupins conventionally inoculated were slightly better than plants inoculated with granules, as shown in FIG. 3 . However, by spring these differences had disappeared, shown in FIG. 4 . It should be noted, differences in biological and grain yield in lupins are not necessarily correlated with nodulation scores.
[0117] In a field experiment to compare nodulation of Vicia faba , either conventionally inoculated (with peat based inoculant) or with rhizobial inoculant composition of the present invention, there were considerable differences noted in early (6 weeks) nodulation scores, as shown in FIG. 1 (1:10, 1:20 and 1:40 refer to compositions of the present invention with varying ratios of peat based inoculant to clay). Following sowing, there was an extended dry period and the conventionally inoculated plants nodulated poorly under this regime. The plants inoculated with the composition of the present invention were able to source adequate rhizobia from the composition when rainfall did return.
[0118] It will be appreciated that different species of crop and pasture legumes may be inoculated with different rhizobial strains.
[0119] The composition and delivery system of the current invention has been developed to provide a more favourable environment for survival of micro-organisms, for example the rhizobia described above, and permits rhizobial respiration to proceed during desiccation, leading to enhanced survival of inoculants and ultimately greater impact on plant growth. This is thought to be due to the lattice structure of the clay allowing impregnation with actively growing rhizobial cells. This obviates the requirement that legume seeds be inoculated immediately prior to planting.
[0120] A further advantage of the present invention is that it aids disease suppression in legume crops. Many crop legumes exhibit a high degree of susceptibility to a range of foliar diseases. With conventionally inoculated legumes (i.e. peat added to the seed surface), fungicides can not be applied directly to seed as the fungicides kill rhizobial cells as well as fungal spores. The present invention aims to alleviate this problem and provide a delivery system and method of inoculation wherein fungicide may be applied to seeds without adversely affecting the rhizobial bacteria which are supplied separately in the clay based granules.
[0121] It is envisaged that the delivery system and composition described hereinabove in respect of the inoculation of legumes with rhizobial bacteria is readily adaptable for broader application in respect of PGPRs and their application to a wide variety of plants, not necessarily limited to agriculture crops.
[0122] It is still further envisaged that the delivery system and composition of the present invention will prove beneficial in the delivery of micro-organisms in additional fields requiring viability to be maintained prior and/or subsequent to delivery/application. One such field is mineral processing and the delivery of bacteria to biological leaching systems, including heap leaches, which typically utilise bacterial strains capable of oxidising the ores and/or concentrates used to form them, in an effort to subsequent liberate valuable metal species therefrom. Typically, a solution containing the bacterial species is applied to the top of the heap and is allowed to percolate therethrough, the pregnant leach solution being collected at the base of the heap and either recycled to the heap or being bled to a metals recover circuit. Bacterial species administered in this manner have included Thiobacillus ferrooxidans, Thiobacillus thiooxidans and Leptospirillum ferrooxidans , in the biooxidation of arsenopyrite, pyrite, pyrrhotite, covellite and chalcopyrite ores, for example. The delivery system and composition of the present invention has application in the delivery of viable bacteria of the appropriate species to biooxidative leach systems, whether they be heaps, dumps, vats or tanks.
[0123] It is yet still further envisaged that the delivery system and composition of the present invention will have application in the delivery of viable micro-organisms in medical and veterinary applications, whether that be by way of oral or rectal administration. The benefits with regard to shelf life remain the same, as does the ability to deliver viable microbes to a target, which may be a certain portion of the gut.
[0124] While advantageous and preferred embodiments of the present invention have been selected as an illustration of the invention, it should be understood by those skilled in the art that changes and adaptations can be made therein without departing from the scope of the invention.
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The present invention relates to a delivery system for the administration of microorganisms, the delivery system including at least one species of micro-organisms, water and an aluminosilicate clay and a method for its preparation and use. The delivery system of the present invention is in part intended to provide an inoculant composition for the inoculant of legumes to stimulate root nodule formation and allow improved capacity for storage prior to use.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method of recognizing speech pauses from the short-time spectrum of a speech signal which may have noise signals superposed on it.
2. Description of the Related Art
Methods of this type are, for example, the prerequisite for the suppression of noise signals when telephone calls are made from an environment with acoustic disturbances. During the speech pauses characteristic parameters of the noise signal are measured and employed, before transmission, to filter out the noise substantially wholly from the signal to be transmitted, using adaptive filters.
German Patent 24 55 477 and the corresponding British Pat. No. 1,515,937, published June 28, 1978, disclose in, column 10 an analog technique for recognition of speech pauses, which is based on the following method: the speech signal is divided into sections of equal lengths and a voltage value is obtained for each section by means of rectification and deriving the mean value, this voltage value being proportional to the average sound volume of the section. Finally, by deriving the mean value of several speech sections a further voltage value is determined, which is proportional to the average loudness of the conversation. By comparing these two mean values it is determined whether a particular section is associated with a speech pause or not.
In the said method of speech pause recognition no account is inter alia taken of the fact that, for example, during continuing speech there are unvoiced intervals which result in an almost total power reduction in the speech signal and the relevant speech sections are therefore erroneously recognized as speech pauses. Such faulty decisions occur in the prior art method more frequently as the extent to which noise signals are superposed on the speech signal increases.
SUMMARY OF THE INVENTION
It is therefore an object of the invention, to provide a method as described in the opening paragraph, in which faulty decisions as defined above are avoided. The method may be performed with digital means, and achieves speech pause recognition even when the average noise power changes only slowly.
The method according to the invention can be used with particular advantage when - as in the application mentioned in the opening paragraph - an arrangement is used for noise suppression, based on a short-time Fourier analysis of the disturbed speech signal. It is then not necessary to separately determine the Fourier coefficients in order to carry out the method according to the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be further described by way of example with reference to the accompanying drawings.
In these drawings:
FIG. 1 is a block diagram to explain the method according to the invention,
FIG. 2 shows various waveforms involved in the method according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the block diagram shown in FIG. 1 the disturbed speech signal is applied to an input terminal E. An analog-to-digital converter A/D produces from the analog input signal a sequence of digitized sampling values. The sampling values are applied to a filter bank FB which determines at each instant τ(n) of a clock-designated central clock hereinafter a set W(n) of M Fourier coefficients Y1(n), Y2(n) . . . YM(n) of the short-time spectrum.
The method in accordance with the invention utilizes only Fourier coefficients whose associated frequencies are located in a frequency between 0 Hz and approximately 3000 Hz, as this range is the range of highest spectral energy density of speech. As a result, speech pause recognition is improved when the spectrum of the noise signal covers a wider frequency range.
From the set W(n) of the Fourier coefficients Y1(n), Y2(n) . . . YM(n), and the preceding sets of Fourier coefficients, a mean-value processor MB determines a short-time mean value G(n), which is approximately a measure of the average power of the disturbed speech signal, the period of time in over which the mean value is determined being of the order of magnitude of 100 ms. The exact averaging procedure will be described in greater detail hereinafter. A unit GL smooths the sequence of short-time mean values G(n). This is to ensure that during the ultimate determination of whether there is a brief speech pause, almost total power reductions in the speech signal caused by unvoiced intervals during continuing speech are not erroneously recognized as pauses. A unit PA in FIG. 1 determines an estimate P(n) of the noise power, that is to say the power of the noise signals, and also sets a first threshold S depending thereon. More details of how the estimate is determined will also be given hereinafter. If the sequence GG(n) of the smoothed short-time mean values is below the threshold S, then a comparator V applies a speech pause indicating signal to a unit EN.
If the unit EN has received successively, for example, 25 times, a signal from the comparator V, then it indicates the presence of a speech pause by producing a signal at its output terminal A.
The filter bank FB determines, for example every 4 ms, a set W(n) of M=30 Fourier coefficients of the short-time spectrum. That is, the period of the central clock amounts to 4 ms. Determining the short-time mean values G(n) at the clock instants τ(n) requires both an averaging of all the Fourier coefficients Y1(n) . . . YM(n) at a particular instant τ(n) and an averaging of the coefficients at different clock instants. To describe the averaging procedure in the form of a formula, an auxiliary quantity H(n) is introduced which is obtained by averaging only those Fourier coefficients which are determined at the instant τ(n) that is to say, ##EQU1## according to whether one wants to employ the arithmetic mean of the amounts or of the squares of the amounts. As using the amounts requires less components, the first possibility will generally be preferred for determining the auxiliary quantity H(n).
According to the invention, the short-time mean value G(n) is now obtained be averaging the quantity H(n) at different clock instants: ##EQU2## The number N of the considered instants is 25.
The recursive method of determining the mean,
G(n)=(1-δ)G(n-1)+δH(n)
is more advantageous, since this requires less components. In that method the short-time mean value G(n) at the clock instant τ(n) is obtained as the linear combination of the short-time mean value G(n-1) at the clock instant τ(n-1) and the auxiliary quantity H(n). A typical value of the constant δ is 0.1.
From the sequence of short-time mean values G(n) two further quantities, namely a smoothed short-time mean value GG(n) and an estimate P(n) for the average noise power are obtained in accordance with the invention at each clock instant τ(n). The smoothed value GG(n) can be recovered with the aid of, for example, a linear digital filter, which, to derive as an output the quantity GG(n), takes the weighted average of three consecutive short-time mean values G(n), G(n-1) and G(n-2) weighting factors (filter coefficients) 1/4, 1/2 and 1/4 have been found to be satisfactory.
A further possibility is filtering by means of a median filter. Then, for example, five consecutive values G(n) . . . G(n-4) are arranged according to value and thereafter the third value is read as the output value GG(n) of the filter.
The continuous determination of the noise power estimate P(n) can also be effected in two different manners. In one procedure a longer speech pause is first determined and then the value of P(n) is updated with a short-time mean value G(n), which is located in this speech pause. Because of the continuous updating of the estimate P(n), speech pause recognition is still possible in the method according to the invention even when the power level changes slowly.
A longer pause is signified when the inequality
|G(n)-G(n-1)|<D=YG(n)
is satisfied K times consecutively. That is, the difference between two consecutive short-time mean values G(n) and G(n-1)must, K times in succession, fall below a limit D. The limit D is chosen proportionally to the short-time mean value G(n), so that the same results are obtained even, when, for example, the level of all the signals are doubled.
The values K=30 and Y=1.1 were found to be advantageous. If G(n) is, for example, the thirtieth value, for which the above-mentioned inequation is satisfied, then the estimate P(n) is updated in accordance with the equation
P(n)=(1-α)P(n-1)+αG(n)
That is to say, the new estimate P(n) is a linear combination of the old estimate P(n-1) and the previously determined short-time mean value G(n) which is contained in a longer pause. For the constant α a value of 0.5 is advantageous. If no longer pause is present, then the old estimate is retained, that is to say P(n)=P(n-1) is set.
A different procedure is used to obtain the best possible estimate P(n) for a slowly varying noise power. This consists of increasing at each clock instant τ(n) the estimate P(n-1) already present, by a fixed amount c, when the estimate P(n-1) is less than the short-time mean value G(n). Each time that the inequality P(n-1)<G(n) is satisfied, the value of P(n) is set at
P(n)=P(n-1)+c.
The constant c can be chosen such that at an unimpeded increase in the estimate will reach a boundary value in one or two seconds. If on the other hand the estimate P(n-1) already present is higher than the instantaneous short-time mean value G(n), then the new estimate P(n) is reduced with respect to the estimate present, more specifically in accordance with the equation
P(n)=(1-β)P(n-1)+βG(n),
which represents the new estimate as a linear combination of the preceding estimate and the instantaneous short-time mean value G(n). A reduction in the estimate can be recognized most distinctly when a value one is chosen for the constant β. Then, namely, it is obtained that P(n)=G(n)<P(n-1). However, values around 0.5 have been found to be more advantageous for the constant β.
The threshold S, which is used to decide whether there is a pause or not, is higher than the estimate P(n). Typical for the relationship between the threshold S and the estimate P(n) is the equation S=1.15P(n), when for the determination of the short-time mean values the amounts of the Fourier coefficients are used. When the squares of the amount are used the relationship is typically S=1.3P(n).
Diagram (a) of FIG. 2 shows an example of the sequence of smoothed (and standardized to one) short-time mean values GG(1), GG(2) . . . of an undisturbed speech signal. The sequence of GG(n) is plotted versus time. The time interval considered has a length of approximately 5 seconds. The position of the speech pauses can be recognized in that there the quantities GG(n) assume the valaue 0.
In diagram (b) that sequence of GG(n) is shown which was recovered from a disturbed speech signal. The speech signals on which the diagrams (a) and (b) are based are identical. The dotted curve in diagram (b) is the sequence of the noise power estimates P(n), which were determined in accordance with the second of the above described possibilities. The result of the speech pause determination is shown in diagram (c). The presence of a speech pause is expressed in this diagram in that the ordinate assumes the value 1 during the speech pause and the value 0 outside the speech pause.
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A method of recognizing speech pauses in a speech signal even when the signal is disturbed by a slowly varying noise signal superposed thereon. Mean values which are an approximate measure of the average power of successive sections of the disturbed signal are determined from the short-time Fourier coefficients of the disturbed speech signal. The sequential short-time mean values are then smoothed by a linear digital filter or a median filter. An estimate of the noise signal power averaged over a few seconds is also recovered from the sequence of short-time mean values. A speech pause is signified when the smoothed short-time mean value (output of GL) more than once falls to a threshold which is proportional to the estimated noise power (output of PA).
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REFERENCE TO PENDING PRIOR PATENT APPLICATION
This patent application claims benefit of prior U.S. Provisional Patent Application Ser. No. 61/989,269, filed May 6, 2014 by ProPhotonix Limited and Adrian Zagoneanu for HEAT SINK FOR OPTICAL MODULE ARRAYS, which patent application is hereby incorporated herein by reference.
FIELD OF THE INVENTION
This invention relates to optical modules and optical module array assemblies in general, and more particularly to heat sinks for optical modules and optical modules array assemblies.
BACKGROUND OF THE INVENTION
There has been increasing demand for optical modules with higher optical output to use as light sources or for processing applications.
The operating lifetime of a light source (e.g., a laser diode) is dependent on, among other things, its operating temperature. A high quality light source, operating at 20° C., could have a lifetime in excess of 100,000 hours. However, as the optical power of the light source increases, the amount of heat generated by the light source also increases, and dissipating this heat can present significant technical challenges to the designer, particularly where the optical module is used in an optical module array assembly where a sizable number of optical modules must be packaged in a relatively confined space.
Failure of a light source is defined as the point in time when the operating current required to maintain a specified output power is increased by some percentage (e.g., 50%) of the original operating current. The output power of a light source is usually measured by a monitor photodiode integrated into the optical module which houses the light source. However, not all optical modules have monitor photodiodes incorporated therein, so the risk of the light source overheating and failing without appropriate detection is substantial.
This “excessive heat” issue is further compounded by the continuous release of new light sources with higher output powers from light source manufacturers, and the placement of high power optical modules in close proximity to each other so as to form dense arrays in optical module array assemblies.
To maximize the optical source lifetimes, and to ensure reliable operation of optical modules, it is necessary to provide adequate heat sinking for the optical module and, in particular, for the light source contained in the optical module.
However, optical modules installed in a heat sink have traditionally been difficult to remove and replace. It would, therefore, be highly beneficial to the user if a defective optical module in an optical module array assembly (having a heat sink) could be easily removed and replaced in the field by a non-technical person in a short period of time without the need for special tools.
In addition to the foregoing, optical modules require associated electronics, generally in the form of a printed circuit board (PCB), to drive the light source in the optical module. In some cases, an internal PCB is incorporated in each optical module. More commonly, however, optical modules are supplied independently of a PCB, and the optical modules are connected to an external PCB. This approach is particularly popular for optical module array assemblies. In this case, all of the optical modules of the optical module array assembly may be driven by a single external PCB. Each optical module plugs into the external PCB via the back end of the optical source of that optical module. As old optical modules become defective, replacement optical modules can simply be plugged into the existing PCB, leading to significant cost savings. The heat sink typically sits substantially parallel to the PCB, with the optical modules extending through, and mounting to, the heat sink.
It is important that the optical module plugs into the external PCB correctly. For example, when a optical module having a laser diode is mounted in a heat sink, the laser diode (within the optical module) must be correctly connected to the PCB (i.e., the positive pin of the laser diode must connect to the positive connector of the PCB, and the ground pin of the laser diode must connect to the ground connector of the PCB). Failure to do so results in malfunction of the laser diode and permanent damage to the laser diode when a voltage is applied.
Therefore, it would also be beneficial to provide a heat sink design suitable for a range of different sizes of optical module array assemblies that allows for easy replacement of defective optical modules and includes features to ensure the proper orientation of the optical modules relative to the PCB for correct electrical connection.
SUMMARY OF THE INVENTION
The present invention provides a novel heat sink for an optical module array assembly in which a defective optical module in the optical module array assembly can be easily removed and replaced in the field by a non-technical person in a short period of time without the need for special tools.
In addition, the present invention also provides a novel heat sink which is suitable for a range of different sizes of optical module array assemblies, which allows for easy replacement of defective optical modules, and which includes features to ensure proper orientation of the optical modules relative to the PCB for correct electrical connection.
In one form of the invention, there is provided apparatus comprising:
a heat sink, said heat sink comprising:
a body formed out of a heat-transmissive material; at least one channel extending through said body, said at least one channel having an inlet port and an outlet port; at least one opening extending through said body, said at least one opening being configured to receive an optical module therein; at least one securement element mounted to said body for releasably securing an optical module within said at least one opening; and at least one alignment element mounted to said body for ensuring appropriate alignment of an optical module received in said at least one opening.
In another form of the invention, there is provided a method for providing light, the method comprising:
providing apparatus comprising:
a heat sink, said heat sink comprising:
a body formed out of a heat-transmissive material; at least one channel extending through said body, said at least one channel having an inlet port and an outlet port; at least one opening extending through said body, said at least one opening being configured to receive an optical module therein; at least one securement element mounted to said body for releasably securing an optical module within said at least one opening; and at least one alignment element mounted to said body for ensuring appropriate alignment of an optical module received in said at least one opening;
positioning an optical module in said at least one opening, said at least one securement element releasably securing said optical module within said at least one opening and said at least one alignment element ensuring appropriate alignment of said optical module received in said at least one opening; and
operating said optical module and passing a fluid through said at least one channel so as to draw off heat from said optical module.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which is to be considered together with the accompanying drawings wherein like numbers refer to like parts, and further wherein:
FIGS. 1 and 2 are schematic views showing an optical module formed in accordance with the present invention;
FIGS. 3 and 4 are schematic views showing a heat sink formed in accordance with the present invention;
FIGS. 5 and 6 are schematic views showing the optical module of FIGS. 1 and 2 being releasably locked to the heat sink of FIGS. 3 and 4 using a spring plunger;
FIG. 6A is a schematic view showing further details of the spring plunger shown in FIGS. 5 and 6 ;
FIG. 7 is a schematic view showing a heat sink/PCB assembly;
FIG. 8 is a schematic view showing the back side of a heat sink to which optical modules have been mounted;
FIG. 9 is a schematic view showing the front side of a heat sink to which an optical module has been mounted;
FIG. 10 is an exploded schematic view showing various aspects of a two-plate heat sink formed in accordance with the present invention; and
FIG. 11 is a schematic view showing additional aspects of a two-plate heat sink shown in FIG. 10 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Optical Modules
Looking first at FIGS. 1 and 2 , there is shown an optical module 5 which may be used in connection with the present invention. Optical module 5 can be based on a wide variety of different light sources 10 such as laser diodes, LEDs, OLEDs, SLEDs, etc. The laser diodes can be single mode laser diodes or multimode laser diodes. The laser diodes can be edge-emitting lasers or vertical-cavity surface-emitting lasers (VCSELs). Optical modules 5 can contain more than one light source 10 , for example, the optical module can contain a 2×2 array of light sources. Optical modules 5 can be any length, e.g., they can be 100 mm in length. Optical modules 5 can be any cross-sectional shape, for example, they can be cylindrical, square, or square with angled edges. In one preferred form of the invention, optical modules 5 comprise a round cross-section such as is shown in FIGS. 1 and 2 . Typically, optical modules 5 range from 6 mm to 30 mm in diameter. Optical modules 5 can have fixed or adjustable focus mechanisms. Optical modules 5 typically include a light source 10 , e.g., a laser diode; and a lens (or a set of lenses) 15 which typically collimate or focus the light beam emitted by light source 10 . Optical modules 5 may also comprise other optical components such as diffractive optical elements, diffusers, polarizers, etc.
Optical modules 5 may not include a PCB within body 20 of optical module 5 . In this case, optical module 5 is driven by an external PCB (see below) to which the optical module is electrically connected, e.g., via pins 25 of light source 10 . Even where optical module 5 does not have a PCB included in body 20 of the optical module, and where optical module 5 is driven by an external PCB, the optical module generally does include some onboard electronics for driving light source 10 . These onboard electronics can range from very simple electronics which simply allow for ON/OFF operation of light source 10 to more complex electronics which allow operations such as adjustable power output, Transistor-Transistor Logic (TTL) and/or real-time diagnostics. Optical module 5 can also comprise pressure equalization features, and/or purge mechanisms for removing contaminants that may enter the interior of body 20 of the optical module over time. If desired, optical module 5 can be optically fiber-coupled. Where optical module 5 is optically fiber-coupled, e.g., via an optical fiber 30 , the optical fiber can be of any type, e.g., single mode, multimode, polarization mode, photonic crystal, etc.
Heat Sink
In accordance with the present invention, and looking now at FIG. 3 , there is provided a novel heat sink 35 . Heat sink 35 is suitable for use with optical module array assemblies of any size, e.g., from one optical module 5 up to thousands of optical modules 5 . The optical modules 5 mounted to heat sink 35 will typically be identical to one another. However, it is also possible for an optical module array assembly to comprise optical modules 5 of varying dimensions, wavelengths, functionalities and/or types and, where this is the case, heat sink 35 is configured to accommodate these varying optical modules. Heat sink 35 comprises a body 40 made of a suitable heat-transmissive material, e.g., brass, steel, aluminum, etc. In one preferred form of the invention, body 40 is manufactured from a single plate 41 formed of metal.
Optical modules 5 are mounted to heat sink 35 via openings 45 formed in body 40 . Openings 45 can be arranged in 1D or 2D arrays. Openings 45 are preferably symmetrically spaced apart from one another, however, if desired, openings 45 can also be staggered or arranged in a random pattern. Openings 45 vary in size and/or taper according to the external geometry of the bodies 20 of the optical modules 5 which are to be received in heat sink 35 .
By way of example but not limitation, a 32-channel heat sink 35 is shown in FIG. 3 . In this form of the invention, body 40 is formed out of aluminum and comprises thirty-two openings 45 that extend from the top face 50 of heat sink 35 to the bottom face 55 ( FIG. 8 ) of heat sink 35 . Generally, the number of openings 45 in heat sink 35 is equal to the number of optical modules 5 which are to be provided in the optical module array assembly. In the example shown in FIG. 3 , openings 45 are arranged in four rows of eight.
Serpentine Channels
In electronic systems, a heat sink is conventionally a passive heat exchanger that cools a device by dissipating heat into a surrounding medium. A heat sink transfers thermal energy from a higher temperature device (e.g., a laser diode) to a lower temperature medium, e.g., a fluid medium. The fluid medium is frequently air, but it can also be water or mixtures of fluids, e.g., a 15% ethylene glycol-water mixture.
The present invention comprises a novel fluid-cooled heat sink for use in an optical module array assembly, i.e., the aforementioned heat sink 35 . As seen in FIG. 4 , heat sink 35 comprises two ports 60 A, 60 B, one of which ( 60 A) is located at one side face 65 of heat sink 35 and the other of which ( 60 B) is located at another, opposite side face 70 of heat sink 35 . One port is an input port and the other port is an output port. The two ports 60 A, 60 B are preferably identical, and hence either port can be used as the input port or the output port. A cooling solution (i.e., the fluid medium) enters heat sink 35 via the input port, travels through serpentine channels 75 formed in heat sink 35 , absorbs heat generated by light sources 10 so as to cool the light sources 10 contained within the optical modules 5 mounted to heat sink 35 , and then exits heat sink 35 via the output port.
The serpentine channels 75 are disposed within heat sink 35 such that when optical modules 5 sit in the heat sink, serpentine channels 75 are disposed at the same “height” as light sources 10 in optical modules 5 , whereby to maximize cooling of the light sources 10 . In other words, serpentine channels 75 are disposed in heat sink 35 such that the cooling solution (i.e., the fluid medium) flowing within serpentine channels 75 will pass adjacent to light sources 10 disposed in optical modules 5 , whereby to efficiently transfer heat from light sources 10 to the cooling medium. Thus, the “vertical alignment” of serpentine channels 75 with light sources 10 ensures that the cooling solution flowing through serpentine channels 75 flows as close as possible to the primary source of heat emanating from optical modules 5 (i.e., the light sources 10 ) so as to maximize cooling of the optical module array assembly.
Serpentine channels 75 can be provided in a variety of channel configurations, depending on the particulars of the optical module array assembly, e.g., depending on array type, the size of the optical modules 5 used therein, the output powers of the optical modules 5 , the light sources 10 utilized in the optical modules, etc. It should also be appreciated that serpentine channels 75 can comprise varying dimensions along their length, e.g., so as to increase their surface area and/or the turbulence of the cooling solution at selected locations along serpentine channels 75 . Heat sink 35 can also comprise more than one input port and/or more than one output port if desired.
FIG. 4 shows an exemplary configuration for the serpentine channels 75 of the exemplary 32-channel heat sink 35 shown in FIG. 3 . For this particular design, to form serpentine channels 75 of heat sink 35 , three bores 80 A, 80 B, 80 C are drilled straight through body 40 of heat sink 35 , extending from side face 65 to the opposing side face 70 . In order to fluidically connect bores 80 A, 80 B, and 80 C together, two additional bores 85 A, 85 B are drilled part way into body 40 of heat sink 35 , preferably perpendicular to the axis of bores 80 A, 80 B, 80 C, i.e., one bore 85 A is drilled inwardly from front face 90 of heat sink 35 and one bore 85 B is drilled inwardly from back face 95 of heat sink 35 . For purposes of illustration, three bores 80 A, 80 B, 80 C and two bores 85 A, 85 B have been shown in FIG. 4 , however, it should be appreciated that more (or fewer) bores 80 A, 80 B, 80 C may be provided and more (or fewer) bores 85 A, 85 B may be provided. In general, the number (and configuration) of bores 80 A, 80 B, 80 C, etc., and the number (and configuration) of bores 85 A, 85 B, etc., will depend on the number of openings 45 provided in heat sink 35 and the spatial arrangement of the openings 45 provided in heat sink 35 .
By placing fluid caps 100 ( FIG. 4 ) to block off some of the exit holes of bores 80 A, 80 B, 80 C, etc., and to block off the exit holes of bores 85 A, 85 B, etc., closed-loop serpentine channels 75 are provided for cooling the optical modules 5 mounted in heat sink 35 . Fluid caps 100 may comprise a threaded screw with an appropriate adhesive so as to form an effective seal, or an adhesive-only barrier, or the welding or braising of a cap within the bores, etc.
It should be appreciated that it is also possible to provide the serpentine channels 75 of heat sink 35 using other methods of manufacture, e.g., casting, 3D printing, etc.
Mounting the Optical Modules to the Heat Sink
Heat sink 35 must be configured to hold optical modules 5 securely within openings 45 so as to provide good mechanical support for optical modules 5 , to provide good thermal contact between optical modules 5 and heat sink 35 so as to allow for efficient thermal transfer from the optical modules to the heat sink, and to allow for easy removal and replacement of optical modules 5 when they become defective.
To this end, the present invention preferably comprises a corresponding hole 105 formed in heat sink 35 for every opening 45 formed in heat sink 35 . See FIGS. 4-6 . These holes 105 preferably extend perpendicular to the longitudinal axes of openings 45 and run from each opening 45 to either the front face 90 , the rear face 95 , or the side faces 65 , 70 of body 40 of heat sink 35 , depending on the location of openings 45 in body 40 . Spring plungers 110 are disposed at the inner ends of holes 105 , near their associated openings 45 . Spring plungers 110 are well suited for fixturing applications where pressure is required for accurate positioning and indexing of components. With the present invention, when an optical module 5 is advanced into an opening 45 of heat sink 35 by the user, the spring plunger 110 is urged outward in its hole 105 , away from the optical module 5 being inserted into opening 45 . Once optical module 5 is in position in opening 45 , spring plunger 110 returns to its original position (e.g., under the power of a spring) and locks the optical module in position within opening 45 (see FIGS. 5 and 6 ), firmly holding optical module 5 in place.
To ensure that spring plunger 110 locks optical module 5 into the correct position, optical module 5 is provided with two unique features. First, the outside surface of body 20 of optical module 5 is provided with an indent 115 ( FIG. 5 ) at the location where spring plunger 110 contacts the optical module. Second, the outer surface of body 20 of optical module 5 comprises a lip 120 ( FIG. 6 ) which acts as a stop as optical module 5 is inserted into opening 20 , thereby ensuring that the optical module is correctly seated in the heat sink, with indents 115 aligned with spring plunger 110 .
In one preferred form of the invention, and looking now at FIG. 6A , spring plunger 110 comprises a body 110 A having a longitudinal bore 110 B formed therein. Longitudinal bore 110 B terminates in a tapered opening 110 C at the distal end of body 110 A. A ball 110 D is positioned in longitudinal bore 110 B and is sized so that ball 110 D can protrude out of tapered opening 110 C but cannot pass completely through tapered opening 110 C. A spring 110 E is disposed in longitudinal bore 110 B and biases ball 110 D out tapered opening 110 C. An end cap 110 F captures spring 110 E in longitudinal bore 110 B. In the preferred form of the invention, body 110 A of spring plunger 110 is threaded, and holes 105 in body 40 of heat sink 35 are threaded, so that spring plunger 110 can be adjustably positioned in a hole 105 , i.e., so that the spring-biased ball 110 D yieldably protrudes into an opening 45 of body 40 of heat sink 35 , whereby to yieldably engage an optical module 5 advanced into opening 45 .
External PCB
As discussed above, in many cases, the optical modules 5 of a optical module array assembly are driven by an external PCB. In this situation, it is generally important that the PCB be kept electrically isolated from the heat sink. To this end, it is common for the PCB to be spaced a reasonable distance away from the heat sink. However, if the light sources 10 of the optical modules 5 are driven in TTL at high frequencies, the distance between the external PCB and the light sources 10 needs to be minimized so as to cut down on parasitics.
In one preferred form of the present invention, and looking now at FIG. 7 , an external PCB 125 is electrically isolated from (i.e., spaced away from), but attached to, heat sink 35 via a plurality of posts 130 , e.g., four posts at each corner of the PCB/heat sink assembly and four posts spread equally across the middle of the PCB/heat sink assembly.
The height of posts 130 is set to match the back end of the optical module 5 , such that the back end of the optical module (which contains the pins 25 of each light source 10 ) will connect directly into external PCB 125 when the optical module 5 is mounted to heat sink 35 . In some cases this connection may be made via an adapter. In other configurations, the analog part of external PCB 125 may be connected directly to the light source 10 of the optical module 5 and the digital electronics will reside on external PCB 125 .
It should be appreciated that the number, height and/or configuration of posts 130 can be varied so as to accommodate different sizes of heat sinks and PCBs. In addition, although one external PCB 125 is shown in FIG. 7 , a plurality of external PCBs 125 could also be provided (e.g., arranged in a side-by-side configuration).
Registration Pins
It will be appreciated that, in addition to securely mounting optical module 5 in openings 45 in body 40 of heat sink 35 , it is also important that the “back end” of optical module 5 (e.g., the end of optical module 5 where the laser diode is located) be correctly circumferentially orientated within a given opening 45 . More particularly, the “back end” of an optical module 5 generally comprises the exposed pins 25 of light source 10 (e.g., a laser diode). See FIG. 8 . Pins 25 are configured to be directly connected to (or indirectly connected to) an external PCB 125 so as to drive the various optical modules 5 in heat sink 35 . When placing the optical module 5 in an opening 45 of heat sink 35 , the user must generally orient the optical module 5 correctly (i.e., “circumferentially” correctly) so as to ensure that the electrical pins 25 of the light sources 10 are aligned with their counterpart connectors (e.g., positive connector and ground connector) on external PCB 125 . A mistake can easily occur as the pins 25 typically appear visually identical. A further complication occurs in the field when a user mounting optical module 5 to heat sink 35 and PCB 125 may not have the training and technical knowledge necessary to ensure correct alignment of connector pins 25 to external PCB 125 .
The present invention solves this problem by combining three elements. First, the light source 10 is positioned within the optical module 5 with a specific orientation during manufacture. Second, the lip 120 of optical module 5 is formed with an indent 135 ( FIG. 9 ). Third, the top face 50 of the body 40 of heat sink 35 comprises a registration pin 140 spatially associated with each opening 45 . When placing optical module 5 into an opening 45 of heat sink 35 , the optical module can only sit fully in an opening 45 if the indent 135 of lip 120 of optical module 5 is aligned with registration pin 140 associated with that opening 45 , so that the registration pin 140 may be received in the indent 135 . See FIG. 9 . Because light source 10 has been pre-aligned relative to indent 135 of optical module 5 (i.e., during the manufacture of the optical module 5 ), the pins 25 of all of the optical modules 5 in the heat sink 35 will be oriented in the same way and in a predetermined fashion. This allows for light sources 10 of optical modules 5 to be correctly connected to external PCB 125 every time, even when optical modules 5 are being replaced. The user does not have to manually align the pins 25 of the optical modules 5 .
Second Embodiment
In the constructions shown in FIGS. 3-9 , body 40 of heat sink 35 is shown as being formed by a single plate 41 . However, and looking now at FIGS. 10 and 11 , body 40 of heat sink 35 can also be formed using two plates 41 A, 41 B instead of one plate 41 . In this form of the invention, the spring plungers 110 for holding the optical modules 5 tightly in the heat sink 35 are preferably located in the bottom plate 41 B. The registration pins 140 are located in top plate 41 A. The serpentine channel 75 , through which the cooling fluid travels, may be drilled out in both plates, e.g., the lower half of serpentine channel 75 may be formed in bottom plate 41 B and the upper half of serpentine channel 75 is formed in top plate 41 A. To ensure that the cooling fluid does not leak out of heat sink 35 , individual O-rings 145 ( FIG. 11 ) may be located around the openings 45 in the heat sink plates 41 A, 41 B. A further primary O-ring 150 ( FIG. 10 ) may be located around the peripheries of the two plates, surrounding all of the optical modules 5 . The two plates 41 A, 41 B are preferably held tightly together via a series of screws 155 .
Third Embodiment
Heat sink 35 can be manufactured such that optical modules 5 are held in place by a screw (e.g., a set screw) rather than by spring plungers 110 .
Alternatively, optical modules 5 may be held in place by screwing a screw directly through the lip 120 of every optical module 5 into the body 40 of heat sink 35 . If desired, more than one screw can be used to secure each module 5 to body 40 of heat sink 35 .
MODIFICATIONS OF THE PREFERRED EMBODIMENTS
It should be understood that many additional changes in the details, materials, steps and arrangements of parts, which have been herein described and illustrated in order to explain the nature of the present invention, may be made by those skilled in the art while still remaining within the principles and scope of the invention.
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Apparatus comprising: a heat sink, the heat sink comprising: a body formed out of a heat-transmissive material; at least one channel extending through the body, the at least one channel having an inlet port and an outlet port; at least one opening extending through the body, the at least one opening being configured to receive an optical module therein; at least one securement element mounted to the body for releasably securing an optical module within the at least one opening; and at least one alignment element mounted to the body for ensuring appropriate alignment of an optical module received in the at least one opening.
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