An apparatus and method for measuring perfusion in a tissue. The method comprising the steps of recording images of the tissue under laser light, calculating a plurality of contrast images from the plurality of images of the tissue, determining a power spectrum of scattered light from the plurality of contrast images, and determining perfusion from the power spectrum. The apparatus comprises a digital video camera, a laser light source, and a processor arranged to operate the camera to produce a plurality of images with different exposure times, receive the plurality of images from the camera and process the images to determine a power spectrum and determine perfusion from the power spectrum.

The following includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art, or relevant, to the presently described or claimed inventions, or that any publication or document that is specifically or implicitly referenced is prior art.
The use of laser light to measure the speed of moving particles, particularly in gases, extends back almost to the invention of the laser. Light scattered back to a detector from a moving particle suffers a Doppler shift equal to the rate of change of the phase path between the source of light and the detector. For example, it has been shown that when examined using minute detector apertures, laser light scattered from motionless skin is Doppler shifted due to the presence of moving blood particles in the dermal layers of the body. Most of the light is returned from essentially immobile scatterers in the tissue, but a portion is returned by a multiple scatter process that involves the immobile scatterers plus scattering by one or more blood particles that flow in the network of looping capillaries within 1-2 mm of the skin surface.
The multiple scatterers complicate the analysis required to quantify such measurements in physiologically useful ways. However, it was found by Bonner and Nossall (Applied Optics 20:2097-2107 (1981)) that the tissue perfusion was given by the first moment of the power spectrum of the Doppler signals, and tissue perfusion can be expressed as the product of the flow velocity and the number of moving scatterers.
Laser Doppler imaging is a current optical technique that is used to evaluate blood flow changes. The output of the instrument is a two-dimensional (2D) flow-related (perfusion, speed, concentration) map over an area of up to 50×50 cm2. The technique is non-invasive because it involves no physical contact. However, present commercial laser Doppler imagers do not completely fulfill all requirements imposed on them by clinical applications. They are slow, special skills are required to use them, and the interpretation of the obtained results is not always objective. Another problem with the Doppler method is that perfusion can only be measured at one site at a time. Mapping perfusion over an area is time consuming and does not take into account any rapid perfusion changes. With regard to the evaluation of perfusion or blood flow in a subject, for example in the skin of a subject, yet another issue with Doppler imaging is the fact that the subject, e.g., the skin or a body part under evaluation, must remain motionless. Thus, commercial laser Doppler imagers and the technique itself are mainly used in medical research projects but not often in clinical practice, despite the tremendous potential of laser Doppler imaging in the medical field. Currently, the two main optical techniques for in vivo monitoring of blood flow are laser Doppler flowmetry and laser speckle contrast imaging.
A speckle pattern is a random intensity pattern produced by the mutual interference of a set of wavefronts. When a surface is illuminated by a light wave, according to diffraction theory, each point on an illuminated surface acts as a source of secondary spherical waves. The light at any point in the scattered light field is made up of waves that have been scattered from each point on the illuminated surface. If the surface is rough enough to create pathlength differences exceeding one wavelength, giving rise to phase changes greater than 2π, the amplitude, and hence the intensity, of the resultant light varies randomly. If light of low coherence (i.e., made up of many wavelengths) is used, a speckle pattern will not normally be observed, because the speckle patterns produced by individual wavelengths have different dimensions and will normally average one another out. This phenomenon has been investigated by scientists for many years, but speckles have come into prominence since the invention of the laser and there are a variety of applications. A familiar example is the random pattern created when a laser beam is scattered off a rough surface. The speckle effect is a result of the interference of many waves having different phases, which add together to give a resultant wave whose amplitude, and therefore intensity, varies randomly. If each wave is modeled by a vector, then it can be seen that if a number of vectors with random angles are added together, the length of the resulting vector can be anything from zero to the sum of the individual vector lengths.
Laser speckle patterns are produced by illuminating the object under test with coherent light. Speckle is the grainy appearance produced by interference between path lengths which differ randomly due to microscopic surface roughness, and may be far field speckle or image speckle. Far field speckle describes the speckled nature of the illumination at some distance from a laser spot shone on a surface, and image speckle describes the speckled appearance of an object illuminated with an expanded laser beam, as imaged by some optical system such as a camera or human eye. Laser speckle contrast imaging uses the image speckle effect, in which the pixels in an image of a uniform surface show intensities in a distribution from black to white. As the object under test moves the speckle pattern translates or changes; at any particular point, the measured intensity fluctuates with object movement.
In a system of perfusion estimation, laser speckle is used to produce full field images of relative motion. Equivalent to the Doppler shift seen at a point, the laser speckle pattern "twinkles" in space because of the light scattered by the moving blood particles when the target is living skin. The greater the rate of twinkling, the more the speckle becomes blurred in an image recorded over a finite time. This twinkling is sometimes termed "biospeckle," and the blurring is conventionally quantified by a contrast parameter K, where K is the ratio of the standard deviation of the light intensity to the mean intensity i.e.
  K  =            σ      s              I      _      where the subscript s denotes spatial variation.
Speckle images of living biological tissues such as skin show a rapidly changing speckle pattern, in contrast to the static speckle pattern produced by a stationary non-living object. This biospeckle effect is due to the scatter from moving cells, such as red cells in flowing blood, relative to the fixed scatterers as such the tissue. The spectrum of this fluctuation is determined by the number and speed of the moving particles.
The fluctuation rate can be measured indirectly by calculating the contrast over small areas of a speckle image taken at some appropriate finite exposure: if the fluctuation period at a certain point in the image is short enough compared to the exposure time, the speckle fluctuations will be blurred. Low contrast areas of the image indicate a high fluctuation rate, hence high rates of cell movement. This phenomenon has been used to produce various similar laser speckle imaging systems. These systems are sensitive to relative tissue perfusion, a measure of blood flow proportional to the product of the speed and concentration in tissue of flowing blood cells. However, the challenge for laser speckle techniques is determining a quantitative measurement of perfusion from the speckle statistics. Notwithstanding opporunities around real-time visualization of speckle contrast, real-time quantitative analysis has hitherto been lacking
Thus, perfusion—blood flow in tissues—can be measured using laser Doppler techniques or laser speckle contrast imaging. Laser Doppler and laser speckle methods essentially measure the same physical effect, though they use different measurement techniques and interpretations. Doppler methods measure perfusion from the first moment of the power spectrum of the fluctuations in light returned from a small area of the tissue (Briers, J. D., "Laser Doppler, speckle and related techniques for blood perfusion mapping and imaging" Physiological Measurement 22:R35-R66 (2001)), which has been shown to be linearly related to blood flow by calculation and in vitro experiments (Bonner and Nossal, "Model for laser Doppler measurements of blood flow in tissue" Applied Optics 20:2097-2107 (1981) and modelling (Jentink, et al., "Monte Carlo simulations of laser Doppler blood flow measurements in tissue" Applied Optics 29:2371-2381 (1990)). This was initially a single point measurement, using a probe to measure the spectrum returned from a small volume of tissue illuminated by laser light, though an image of an area of tissue can be produced by scanning the measurement point. Laser speckle perfusion measurements, on the other hand, use the spatial statistics of the fluctuating laser speckle pattern (biospeckle) recorded by a camera at a finite exposure to generate a map of relative perfusion. Laser speckle perfusion is an area measurement by nature, producing an image with every exposure, by comparison with laser Doppler images produced by scanning. As noted above, a current challenge for laser speckle techniques is determining a quantitative measurement of perfusion from the speckle statistics.
Thus, it will be appreciated that laser Doppler and laser speckle imaging are two optical non-invasive techniques that are used to obtain 2D maps of blood flow in biological tissues, and each of these existing techniques has benefits and drawbacks for measuring the blood flow. Laser speckle contrast imaging can be seen as a real-time imaging technique, but the interpretation of its response to changes in flow parameters such as speed and concentration is problematic. In contrast, laser Doppler imaging has clearer biological interpretation but it is not a real-time technique.
In one embodiment, a new laser speckle imaging system takes speckle contrast measurements over multiple exposure times and uses temporal autocorrelation information derived from speckle contrast measurements to provide spectral information and a perfusion index that is precisely equivalent to that produced in laser Doppler methods.
In another embodiment, numerically constructed autocorrelation data are approximated by mathematical functions with an adjustable parameter τc. The speckle contrast information is determined from each of the plurality of images and a plurality of contrast images are formed therefrom. From the plurality of contrast images, one or more parameters of a temporal autocorrelation function representative of tissue speckle are derived. A perfusion value of a fluid moving through the medium is determined from the one or more parameters.
The various embodiments of the invention described and claimed herein thus overcome the drawbacks of laser speckle imaging and provide particulate flow and velocity images in real time over a scanned area that are equivalent to laser Doppler images taken at a static single point.

Laser speckle imaging systems and methods


The present invention involves a method for prophylaxis or treatment of an animal for systemic hypotension induced by endotoxin and/or a biological response modifier such as the cytokines, IFN, TNF, IL-1 or IL-2 and the like. Said method involves administering, preferably intravascularly, a therapeutically effective amount of dobutamine and an inhibitor of nitric oxide formation from arginine. Although preferable administration is intravascular, it is contemplated that other parenteral administration routes such as intraperitoneal, intramuscular or subdermal injection, for example, may prove useful. Enteral or topical administration of arginine analogs may also prove beneficial under certain clinical conditions.

The present invention relates to the alleviation of hypotension induced by nitrogen oxide production. Research relating to the present invention was supported by government research grants which gives the United States government rights in the present invention.
In 1980, Furchgott and Zawadski (Nature 288:373-376 1980) demonstrated that endothelial cells, which line blood vessels, can be stimulated to release a substance which relaxes vascular smooth muscle i.e., causes vasodilatation. Since the chemical nature of this substance was completely unknown, it was simply named endothelium-derived relaxing factor (EDRF). It is now widely accepted that many naturally-occurring substances which act as physiological vasodilators mediate all or part of their action by stimulating release of EDRF; these substances include acetylcholine, histamine, bradykinin, leukotrienes, ADP, ATF, substance P, serotonin, thrombin and others. Although the extremely short lifetime of EDRF (several seconds) hampered efforts to chemically identify this molecule, in 1987 several laboratories suggested that EDRF may be nitric oxide (NO.), which spontaneously decomposes to nitrate and nitrite. A fundamental problem in accepting this No. hypothesis was that mammalian systems were not known to contain an enzymatic pathway which could synthesize NO.; additionally, a likely precursor for NO. biosynthesis was unknown. After observing that the arginine analog N.sup.G -methyl-L-arginine (L-NMA) could inhibit vascular EDRF/NO. synthesis induced by acetylcholine and histamine, and that EDRF/NO. synthesis could be restored by adding excess L-arginine, it was proposed that arginine is the physiological precursor of EDRF/NO. biosynthesis (Sakuma et al., PNAS 85:8664-8667, 1988). Additional evidence supporting this proposal was reported almost simultaneously. It was also later demonstrated that inhibition of EDRF/NO. synthesis in the anesthetized guinea pig raises blood pressure, suggesting that EDRF/NO. is an important physiological regulator of blood pressure (Aisaka et al., BBRC 160:881-886, 1989). Notwithstanding the accumulated evidence supporting synthesis of NO., it is understood by those skilled in the art that other nitrogen oxides may be present and may be active in reducing blood pressure. Within this specification, the acronym NO. will be understood to represent nitric oxide and any additional vasoactive nitrogen oxides.
It was demonstrated that macrophage cells become "activated" by 12-36 hour treatment with gamma-interferon, bacterial endotoxin and various cytokines. This "activation" is associated with initiation of tumor cell killing and generation of nitrite and nitrate from L-arginine. It was also observed that activated macrophages actually make NO. from L-arginine (just like endothelial cells) and that this NO. subsequently reacts with oxygen to form more oxidized nitrogen metabolites which appear to be physiologically inert (Stuehr et al., J. Exp. Med. 169:1011-1020, 1989). The enzyme responsible for NO. synthesis (nitric oxide synthase) has been partially characterized by some of the present inventors (Stuehr et al. BBRC 161:420-426, 1989) and acts to oxidize the terminal amino group of arginine, resulting in production of NO. and citrulline. It is now believed that macrophage-derived NO. is an important tumoricidal and bactericidal agent. Since bacterial endotoxin, gamma-interferon and other cytokines can trigger NO. generation by macrophage cells it appeared that: 1) endothelial cell NO. generation may be stimulated by similar stimuli and 2) septic shock (i.e., systemic vasodilatation induced by bacterial endotoxin) may result from massive activation of NO. biosynthesis. Speculation that the latter hypothesis was correct was fueled by a prior report that urinary nitrate levels are grossly elevated by treatment of rats with bacterial endotoxin (Wagner et al., PNAS 80:4518-4521, 1983).
Cytokines are well known to cause morphological and functional alterations in endothelial cells described as "endothelial cell activation". Distinct immune-mediators such as tumor necrosis factor (TNF), interleukin-1 (IL-1), and gamma-interferon (IFN or I) appear to induce different but partially overlapping patterns of endothelial cell activation including increased procoagulant activity (Bevilaqui et al., PNAS 83:4533-4537, 1986), PGI2 production (Rossi, Science 229,174, 1985), HLA antigen expression (Pober et al., J. Immunol. 138:3319-3324, 1987) and lymphocyte adhesion molecules (Cavender et al., J. Immunol. 138:2149-2154, 1987). Although these cytokines are reported to cause hypotension, vascular hemorrhage, and ischemia, the underlying mechanisms of altered vasoactivity are unclear (Goldblum et al., Infect. Immun. 57:1218-1226, 1989; Tracey et al., Science 234:470, 1986). A potential mediator of altered vasoactivity is EDRF.
In both clinical and animal (Dvorak, et al., J. Nat'l. Canc. Inst. 81:497-502, 1959) studies on the effects of biological response modifiers a major dose limiting toxicity has been hypotension and vascular leakage.
The cardiotonic drug dobutamine has been used as an addition to a standard treatment protocol, to treat patients in septic shock. Results obtained indicated that dobutamine did not significantly increase mean arterial pressure but did increase oxygen supply and consumption (Vincent et al., 1980, Critical Care Medicine 18:689-693).
Kilbourn et al. described a decrease in blood pressure and cardiac output in dogs treated with endotoxin or IL-1 (BBRC 178:823-829, 1991; JNCI 1992 in press). The administration of N.sup.G -methyl-L-arginine (NMA) partially restored blood pressure but further decreased cardiac output. This result was recently confirmed by Klabunde et al. (Klabunde BBRC 178:1135-1140, 1991). Further studies showed that NMA decreases cardiac output in normal animals (not treated with endotoxin) an effect which is increased at higher doses of NMA (Kilbourn et al. BBRC 178:823-829, 1991; Klabunde et al. Eur. J. Pharm. 199:51-59, 1991).

Use of cardiotonic drugs and inhibitors of nitric oxide synthesis to alleviate pathologic hypotension

Board of Regents, the University of Texas System


A bill acceptor assembly for accepting bills, vouchers, scrip, tickets and/or currency at a gaming table. The bill acceptor assembly includes a note feeder having an intake opening adapted to receive one or more notes. The note feeder may be mounted to a table to allow a user to insert notes into the intake opening. The notes are passed to a validator located underneath the table. The validator is configured to validate the notes and separate valid notes from invalid notes. The validator passes the valid notes to a cash box located underneath the table and passes the invalid notes to a rejection slot formed on the note feeder.

1. Field of the Invention
The present invention is directed to a bill acceptor adapted for mounting on a gaming table, kiosk dispensing assembly or checkout counter. In particular, the invention relates to the design and operation of a bill acceptor which can accept a stack of individual notes in a receiving slot or bulk note feeder mounted to the gaming table, kiosk or counter, and the method by which it processes the notes one at a time and passes validated notes through to a secure cash box.
2. General Background and State of the Art
Conventional gaming tables located in casinos are generally used to play games such as blackjack, poker, roulette, baccarat, and craps. The table may have an outer periphery containing a plurality of player locations and a dealer's location located generally opposite the player locations. From the dealer's location, the dealer controls the pace and operation of the game including for example dealing the cards, paying winning wagers and collecting losing wagers. The operation of a gaming establishment is highly regulated and strictly monitored. Systems adapted for use in the gaming industry are thus required to meet very high design and reliability standards.
A dealer's responsibilities include exchanging currency or notes received from a player, or credits provided to a player, for casino chips. Generally, when a player wants to exchange currency or notes for chips at the gaming table, the player gives the currency or notes to the dealer. Notes, as used herein, can include local and foreign currency, casino scrip, and casino issued tickets. The dealer counts out and then spreads the currency or notes on the playing surface of the gaming table. Video surveillance systems view each of the tables and may confirm the dealers counting of received notes. The dealer is sometimes required to notify a Pit Boss that the dealer is exchanging currency or notes. The Pit Boss in turn must be a running accounting of the money in play on each of the tables that he or she is supervising. After receiving an approval from the Pit Boss, the dealer accepts the currency or notes and deposits them into a slot accessible from the playing surface of the gaming table. The slot leads to a channel for transporting the currency or notes from the slot to a cash box located below the playing surface. A plate may be used to push the currency or notes into the slot and ensure that the currency or notes properly fall into the cash box. Generally, the cash box beneath the gaming table does not include a stacking assembly to receive and stack in an organized manner the notes received, thus, when the cash box is removed from the gaming table and taken to the counting room, the notes must be manually removed, sorted, stacked and counted. Gaming regulations may require that the receipts on every table be audited at least once per day, thus requiring a manual sort and count for each active gaming table at least once per day.
The revenues received on the gaming tables are a significant source of income for a casino. Accordingly, the high volume of currency or notes exchanged invites the risks of receiving counterfeit currency or notes. Unlike slot machines, wherein the implementation of integrated bill acceptors in the slot machines has diminished the casinos' risk of receiving counterfeit currency, most gaming tables remain susceptible to this risk. Due to the increased sophistication of counterfeiters and the increasing difficulties in discriminating between authentic and counterfeit currency, the manual or dealer inspection method of accepting currency on gaming tables is inadequate to protect casinos from currency fraud.
Further, as the use of casino scrip and casino tickets increases or other types of cash equivalents are adopted, there is a risk that these forms of revenue could be compromised or counterfeited. Accurate accounting of these alternative forms of notes may require that they be validated upon receipt, and the validation or authentication may require electronic communication with a central server system.
A few attempts have been made to patent the use of a bill acceptor assembly on electronic gaming tables. For example, U.S. Pat. No. 5,775,993 ("the '993 patent") issued to Fentz et al. discloses a bill acceptor assembly mounted at each player station located around an electronic roulette wheel. Similarly, in U.S. Pat. No. 5,588,650 ("the '650 patent"), each player console located around an automated roulette wheel includes a bill acceptor. In both of these patents, a computer, not a human being, directs the game. A player can insert money into the bill acceptor to earn credits at any time, even though the player may not be able to place a bet until the next betting period. Yet, both the '993 patent and the '650 patent have two fundamental flaws. First, both patents use traditional single-feed bill acceptors where the player must insert one note at a time into the bill acceptor. The bill acceptors in the '993 patent and the '650 patent are not designed to accept multiple notes at one time. At a gaming table, players may start their betting with a large sum of money which, in the configuration of the '993 or '650 patents, would require each player to feed each note one at a time into the bill acceptor. The effort involved in feeding each note can be time consuming and frustrating, and even more so if the bill acceptor does not accept every note on the first feeding attempt.
Second, incorporating a bill acceptor into a computerized gaming table does not involve the same difficulties as incorporating a bill acceptor into a conventional gaming table operated by a human dealer. On the computerized gaming table, a computer using preprogrammed software manages each player's credits, operates the game, calculates and pays out all winnings, and collects any losing wagers. No casino tokens or notes are dispensed until a player cashes out. On the other hand, a gaming table dealer or operator has to do all of the cash intake, chip or token distribution and wagering transaction functions by himself or herself. In addition, the operator is given the responsibility of watching each player to ensure that he/she does not cheat. Neither the '993 patent nor the '650 patent explain or address the many concerns of how to incorporate the bill acceptor into a human operated gaming table. For example, neither patent discloses how the operator would know how much money has been inserted into the bill acceptor. This disconnect in information would prevent the operator from knowing how many tokens to give back to the player.
Accordingly, a system for accepting valid currency and rejecting counterfeit currency on a conventional gaming table would be beneficial to the gaming industry. Such a system would increase the casino's profitability by decreasing the amount of counterfeit currency it may receive. Moreover, a bill acceptor capable of accepting and validating a stack of notes would significantly decrease the delay involved in feeding one note at a time into the bill acceptor. In view of the degree of sophistication involved and the necessary design and operation of such a bill acceptor that will be serviceable in the gaming industry, it may also be appreciated that a bill acceptor satisfying the requirements of the gaming industry will have wide application to a number of applications, including for example self serve kiosks and checkout counters.

Bulk note feeder assembly for table game validator assembly


The curvature of a circular arc constituted by a side of a suction groove is made larger than that of a circular arc constituted by a side of a discharge groove. Thus, when the suction groove and the discharge groove are viewed in the axial direction of a drive shaft, the distance between the suction groove and the discharge groove in the radial direction of a rotary portion is short in a region intersecting with a line W perpendicular to a centerline, and increases in accordance with a decrease in distance from containment portions. It is therefore possible to ensure a sufficient distance between the discharge and suction grooves and enhance a total fluid pressure generated therebetween, and the contact surface pressure that is necessitated by a second side plate to obtain a press-back force when being in contact with an outer rotor and an inner rotor is reduced.

The use of an internal gear type rotary pump such as a trochoid pump or the like as a pump for a braking device has been conventionally proposed (e.g., see Japanese Patent Laid-Open Publication No. 2004-11520).
FIGS. 5A, 5B, and 5C are cross-sectional views of a conventional rotary pump for a braking device. FIG. 5A is a cross-sectional view of the rotary pump that is cut along a plane perpendicular to its rotating axis. FIG. 5B is a cross-sectional view taken along a line A-A in FIG. 5A. FIG. 5C is a cross-sectional view taken along a line B-B in FIG. 5B.
The rotary pump shown in FIGS. 5A, 5B, and 5C is composed of an outer rotor 51 having an inner toothed portion 51a along an inner periphery thereof, an inner rotor 52 having an outer toothed portion 52a along an outer periphery thereof, a casing 50 for accommodating the outer rotor 51 and the inner rotor 52, and the like. The outer rotor 51 and the inner rotor 52 are disposed in the casing 50 with the inner toothed portion 51a and the outer toothed portion 52a meshing with each other to form a plurality of interstitial portions 53.
The casing 50 is composed of a first side plate 71 disposed on an end face of the outer rotor 51, a second side plate 72 disposed on an end face of the inner rotor 52, and a central plate 73 in which a circular hole corresponding in shape to the outer rotor 51 is formed. The outer rotor 51 and the inner rotor 52 are accommodated in a rotary chamber formed by the casing 50.
Given that a line passing through both a central axis X of the outer rotor 51 and a central axis Y of the inner rotor 52 is a centerline Z of the pump, a suction port 60 and a discharge port 61 communicating with the interstitial portions 53 are provided on opposed sides with respect to the centerline Z. When the pump is driven, the inner rotor 52 makes a rotational movement via a drive shaft 54 whose center coincides with the central axis Y of the inner rotor 52. In accordance with the rotational movement of the inner rotor 52, the outer rotor 51 also rotates in the same direction due to the meshing of the inner toothed portion 51a with the outer toothed portion 52a. In this case, the respective interstitial portions 53 increase and decrease in volume while the outer rotor 51 and the inner rotor 52 rotate by 360°. Thus, brake fluid is sucked from the suction port 60 and discharged from the discharge port 61.
One axial end face of the rotary pump is sealed by a sealing member 100 equipped with an elastic member 100a such as rubber and a resin member 100b. More specifically, the sealing member 100 is accommodated in a sealing groove portion 71b formed in a side seal 71, and performs a sealing function when the elastic member 100a presses the resin member 100b.
The other axial end face of the rotary pump is mechanically sealed by bringing end faces of the inner rotor 52 and the outer rotor 51 into direct contact with the second side plate 72. The outer rotor 51 and the inner rotor 52 are pressed toward the second side plate 72 by the resin member disposed on said one face and a brake fluid pressure. This pressing force brings the outer rotor 51 and the inner rotor 52 into contact with the second side plate 72. In this manner, the above-mentioned mechanical sealing is realized.
In the case where one axial end face of the rotary pump is thus mechanically sealed, the friction resistances between the outer rotor 51 and the inner rotor 52 on the one hand and the second side plate 72 on the other increase on the side of that end face, thus causing an increase in driving torque. Also, the contact areas between the outer rotor 51 and the inner rotor 52 on the one hand and the second side plate 72 on the other increase. Therefore, especially at a low temperature corresponding to a high viscosity of brake fluid, the shear resistance of brake fluid increases and thus causes an increase in driving torque.
Thus, in the conventional rotary pump, a suction groove 72d communicating with the suction port 60 and a discharge groove 72e communicating with the discharge port 61 are provided in the second side plate 72 on the mechanically sealed side.
The suction groove 72d and the discharge groove 72e serve to introduce fluid pressures into the suction port 60 and the discharge port 61, press back the outer rotor 51 and the inner rotor 52, and decrease a force for pressing the outer rotor 51 and the inner rotor 52 to the second side plate 72, thus achieving a reduction in friction resistance. This makes it possible to prevent an increase in driving torque.
In the aforementioned conventional rotary pump, as shown in FIG. 5C, the curvature of a circular arc constituted by a side 72ea of the discharge groove 72e on the side of the drive shaft 54 is set equal to that of a circular arc constituted by a side 72da of the suction groove 72d facing the side 72ea of the discharge groove 72e. That is, an illustration in FIG. 6 is obtained by partially enlarging the discharge groove 72e and the suction groove 72d in FIG. 5C. Thus, centers O1 and O2 of the circular arcs constituted by the sides 72da and 72ea respectively are identical to each other. Accordingly, when the suction groove 72d and the sealing groove portion 71b are viewed in the axial direction of the drive shaft 54, the distance between those sides is basically constant.
The suction groove 72d is axisymmetrical with respect to the line W perpendicular to the centerline Z passing through the central axis Y. From the side facing the discharge groove 72e to a region communicating with the suction port 60, the suction groove 72d is formed as an inclined straight line portion 72db and has a gradually increased groove width in a direction parallel to the centerline Z.
By conducting an endurance test as to the rotary pump having the suction groove 72d and the discharge groove 72e formed as described above, the inventors have confirmed contact traces on the second side plate 72 in a region from the straight line portion 72db of the suction groove 72d to the discharge groove 72e. These contact traces are considered to be ascribable to a partial increase in contact surface pressure and thus in contact resistance between the second side plate 72 on the one hand and the outer rotor 51 and the inner rotor 52 on the other. This increase in contact resistance is considered to be the cause of an increase in driving torque of the rotary pump.


A discrete powder which includes particles in which a biliquid foam has been entrapped within a matrix of a polymeric material. A process for the preparation of these discrete powders includes the steps of: i) preparing a biliquid foam, ii) forming a dispersion of the biliquid foam in an aqueous solution, suspension or dispersion of a polymeric material, and iii) subjecting the dispersion to drying under conditions such that a discrete powder is formed.

1. Field of the Invention
The present invention relates to biliquid foam entrapment and, in particular, to a biliquid foam entrapped within a matrix of a polymeric material which is in the form of a discrete powder.
2. The Prior Art
The entrapment of oils or oil soluble substances (especially perfumes and coloured dye precursors) in microcapsules and their subsequent coating onto paper and other surfaces is well known in the art. Microcapsules of this type comprise individual droplets of oil or oil soluble substances (of size ranging from sub-micrometer to tens of millimeters in diameter) around which polymer walls have been formed by one of a number of chemical processes. Usually such microcapsules are prepared as an aqueous suspension which is then capable, with the addition of suitable modifying reagents, of being sprayed or printed onto paper and other surfaces. The object in so doing is usually to prevent the evaporation of volatile substances (for example, perfumes) or the degradation or chemical reaction of oil soluble species (for example, colourless dye precursors) until the microcapsules are broken by the application of shear forces by scratching or scraping the coated surface with the consequent release of their contents. Such coatings find major uses, for example, in the forms of "scratch and sniff" perfume coatings or NCR (No Carbon Required) paper.
However, these microcapsules suffer from a number of disadvantages.
Firstly, the process by which microcapsules are formed is a lengthy and uncertain one in which control over temperature, pH and the absence of any form of contamination is essential. The formation of microcapsules, for example, by complex coacervation from gelatin and an anionic complexing species such as gum acacia takes many hours and demands very close control of pH, temperature and cooling rate. Similarly, the formation of microcapsule walls from aminoplast resins, such as melamine-formaldehyde or urea-formaldehyde takes at least eight hours during which precise control over all controllable parameters needs to be effected. Moreover, the effectiveness and completeness of any individual encapsulation process (and therefore the quality of the microcapsules so formed) depends largely on the chemical nature of the oil and/or oil soluble substances being encapsulated.
A further disadvantage of microcapsulation is that the thickness and therefore the strength of the microcapsule wall is variable and is not easily is controllable and varies with the nature of the oil or oil-soluble substances being encapsulated. Thus microcapsules made by the same process but from different oils may have widely differing strengths and resistance to breakage during the printing process and during subsequent storage and use.
A yet further disadvantage of microencapsulation is the limited number of chemical processes and the limited number and type of polymeric wall materials which are available to form them. The choice as to the properties of the wall materials is consequently limited with regard to their flexibility, tensile strength, permeability, chemical inertness, mammalian toxicity and other properties including solubility and melting point (if any). In addition, some of the chemicals commonly used in the wall forming process are themselves highly irritating and may themselves be toxic such, for example, as the use or release of formaldehyde (a potential carcinogen) during the manufacture of aminoplast resin walls. Moreover, the remaining traces of formalin in the resulting microcapsule suspension are virtually impossible to eliminate to below acceptable levels for uses of microcapsules and requires special precautions to be taken during the manufacturing process.
Whilst many of the processes to produce microcapsules produce dispersions of the microcapsules in a fluid medium, they can also be produced in the form of a powder.
Other methods of encapsulating oil within a powder are generally based upon the drying of an oil-in-water dispersion. Examples of this prior art include EP-B-0938932 which discloses a process for manufacturing a cosmetic and/or dermatological powder in which an oil-in-water dispersion comprising at least one modified starch is dehydrated to form a powder and U.S. Pat. No. 6,129,906 in which a granular powder is formed by spray drying an aqueous dispersion of a silicone oil and a water-soluble carrier, the silicone oil being present in the dispersion as discrete droplets having a droplet size in the range of from 0.5 μm to 20 μm.
WO 99/05299 discloses a surface coating in which droplets of a non-polar substance are trapped within a polymer film, the surface coating being prepared by drying a dispersion of a film forming polymer containing droplets of a suspended biliquid foam or emulsion. Surface coatings only are disclosed and this reference does not teach the drying of the dispersions to form a powder.

Powder formed of particles of biliquid foam entrapped within polymeric matrix


A process for cost-effectively and rapidly insulating a desired surface with spray foam insulation is described which includes the application of a polyurethane foam dispensed through heated conduits into a dispensing gun having a nozzle with essentially planar divergent lips having a triangular prism opening, the lips of the nozzle diverging at an angle of between about 5 and 35° inclusive, more preferably between 8 to 15° inclusive, most preferably 10 to 12° inclusive, thereby achieving application rates which are in excess of 70 Ft2/min, and optimally in excess of 100 Ft2/min.

There are numerous applications in which spray polyurethane foam is used at a site for any number of applications in, but the most traditional use in the building trades is as a source of insulation. The Department of Energy reports that every year the average home wastes up to 40% of the energy used for heating and cooling as air moves through gaps, penetrations, and cracks in the exterior shell of the house, also known as the building envelope. Spray foam insulation is gaining in popularity because of its many benefits over conventional fiberglass insulation. Spray foam is able to fill in cracks and crevices which are too small for fiberglass insulation. The seamless application of the spray foam eliminates air infiltration, which reduces energy waste. Polyurethane spray foam insulation acts as a sound insulator, reduces vibration, and improves the indoor air quality. Also, polyurethane has the highest resistance to heat transfer, called R-value, per thickness of any common insulating product. Polyurethane spray foams are also moisture, mold, fungus, and insect repellant.
When using insulation, two factors are considered important: the resistance to heat transfer (R-value); and the ability to act as an air barrier. A high R-value indicates heat will travel slowly through the material. A low R-value indicates heat will travel quickly through the material. R-value is calculated by a formula that considers the thermal conductivity, k, and the thickness of the material. It is essential to consider the thickness of the material because a very thick material with a very high R-value over the total thickness, might have a lower R-value per unit than a very thin material with an average R-value. Closed cell polyurethane foam insulation has the highest R-value per thickness of any common insulating material.
The ability of the insulation to act as an air barrier is also critical. Pressure differences between the inside and outside of an enclosure cause air leakage to occur. Differences in pressure can be caused by many environmental factors such as temperature differences and wind. Air leakage contributes to warm air leaving an insulated area and cold air entering the area and can occur through cracks, gaps, openings, or through porous walls and insulation. An ideal insulation will minimize air leakage, keeping the warm air inside and the cold air outside of the insulated enclosure. Polyurethane foam insulations act as an air tight barrier, significantly lowering air infiltration.
The polyurethane foam insulation for such in-situ applications is typically supplied as a one-component froth foam or a two-component froth foam. A one-component foam means both the resin and isocyanate for the foam are supplied in a single pressurized container and dispensed from the container through a valve or gun attached to the container.
A two-component "froth" foam means one component is supplied in one pressurized container, typically the "A" container (i.e., polymeric isocyanate, fluorocarbons etc) while the resin is supplied in a second pressurized container, typically the "B" container (i.e., polyols, catalyst, blowing agents, flame retardants etc.). There are advantages and disadvantages to one-component and two-component foams. One advantage of the two-component system is its relatively long shelf life resulting from the fact that the chemicals are not mixed until they encounter one-another in the dispensing gun. This invention relates to two-component foams.
Typically two-component kits use pressurized cylinders about 7½″ in diameter, containing 1-5 gallons (10-50 pounds) which are connected by hoses to a dispensing gun. The two components of the foam are combined in the dispensing gun, and applied directly to the surface being insulated. When the two components combine, an exothermic reaction takes place allowing the gases in the froth to expand, forming small bubbles which become trapped in the mixture. Time must be given to allow the foam to cure and harden, giving it the ability to support itself. The volume of the foam expands as it cures, the amount of expansion that occurs is controlled by the formula of the foam being used. Polyurethane foam has natural adhesive qualities which allow such foams to bond strongly to any number of substrate surfaces.
As the foam cures, the gas bubbles trapped in the foam cause the pressure within the mixture to fall below that of the environment it is in. As air from the environment enters the mixture the pressure within the foam is restored to the levels of its surrounding, causing the foam to harden from the outside towards the surface it is applied to. As the foam hardens the R-value increases until it is completely cured. The time this process takes, as well as the final density of the foam varies with the specific formula of the foam being used.
Polyurethane froth foam reacts with water, and therefore must be applied only to dry surfaces. Humidity within the environment in which the foam is being applied should also be considered. The presence of high humidity in the environment or moisture on the surface being sprayed degrades the adhesion of the foam to the surface, disrupting the complete bonding to the desired surface and allowing the foam to be easily peeled off the wall. Cold temperatures have the same affect on the foam, causing the moisture on the substrate to freeze into ice crystals, disrupting bonding to the desired surface. The surface being sprayed and the ambient temperature must be of a minimum temperature that varies with the formula of the foam and the dispensing system being used to apply the foam. The technical data sheet for a popular polyurethane spray foam that is commonly used in the industry currently specifies the spray foam only be applied between temperatures of 50° F. and 110° F.
Variations of the elements of spray foam application systems are known in prior art. Examples of two-part foam dispensing guns can be found in Fomo Products, Inc.'s U.S. Pat. No. 4,550,863; Fomo Products, Inc.'s U.S. Pat. No. 5,242,115; Fomo Products, Inc.'s U.S. Pat. No. 5,429,308; and Fomo Products, Inc.'s U.S. Pat. No. 6,345,776. Examples of a nozzle for a two-part foam dispensing gun can be found in Fomo Products, Inc.'s U.S. Pat. No. 6,840,462. Spray foam polyurethane insulation are also commercially available, for example DOW Chemical's SPF insulation system, however the system of this invention contains numerous performance improvements over current commercially available systems such as increased application rates and the ability to be utilized under a broader range of environmental factors. To date the elements of the system of this invention as well as the extra features incorporated into this invention have not been combined to find a solution to the industry need for a portable, rapid system for insulating desired surfaces in the harsh construction environment which allow a two-component foam to be applied at temperatures lower than 50° F., certainly lower than 32° F., and more preferably at temperatures as low as 20° F. without peeling.


A quality control system (104) comprises at least one test system (107) and a host computer (122) having a database (130), coupled via a communication link (124). The test system (107) interfaces (120) with a product (118) and obtains its product identifier. The test system (107) outputs, to the host computer (122), an empty file named for the product identifier and a label indicating the type of data to request. The host computer (122), responsive to reading the file name of the empty file, queries the database (130) according to the product identifier and the label. The host computer (122) renames the empty file according to the requested data retrieved via the query. The test system (107), responsive to reading the renamed empty file, tests the product (118) according to the requested data.

To remain competitive, a manufacturer must employ a quality control system capable of gathering information about each of the products it manufactures. One such quality control system includes one or more test systems coupled via a communication link to a host computer having a database. A shared file directory is employed by the host computer to negotiate communications between the test systems, the communication link, and the database. Each test system interfaces with a product and subjects the product to tests. Once the tests are concluded, the test system outputs a file containing test result data to the shared file directory. The host computer opens the file in the shared file directory, reads the test result data from the opened file, and inserts the test result data into the database. Aside from test result data provided by the test systems, the database also contains a plurality of other information about each product from other systems located in the manufacturing environment and visited by each of the products prior to delivery to the test systems. Such information includes model number data, test status data, repair data, defect data, or the like.
Unfortunately, the test systems only communicate unidirectionally--from the test system to the database--and can not retrieve previously stored product information. As a result, each of the products must employ a product identifier contained in, for example, a bar-code attached to the product. The product identifier includes a unique designator to differentiate one product from another and a model designator to designate the model of the product. An example of such a product identifier is "2TWP008", wherein "2TWP0" is the unique identifier and "08" designates the model. The test system obtains the product identifier during interfacing, extracts the model designator from the product identifier, and configures itself according to the model designator so as to test the product as that particular model. However, the use of product identifiers having model designators increases manufacturing costs because, for example, a separate set or roll of preprinted bar-codes must be specifically purchased for each model and is limited for use with only that model. The use of product identifiers having model designators also adds unwanted additional complexity to the manufacturing system. The data "stored" on each product (i.e., the model designator in the product identifier) duplicates that which must be maintained in the database.
Therefore, what is needed is an apparatus and method that permits bi-directional messaging between a test system and a database so as to allow the test system to retrieve product information, such as a model number, from the database in substantially real-time and, thereby, eliminating the need for information redundancy in the manufacturing system.

Quality control system employing bi-directional messaging using empty files


Various implementations described herein are directed to an integrated circuit for implementing low power input gating. In one implementation, the integrated circuit may include a chip enable device configured to receive and use a clock input signal to toggle a control input of memory based on a chip enable signal. The integrated circuit may include a latch device configured to latch the control input of the memory. The integrated circuit may include a latch enable device coupled between the chip enable device and the latch device. The latch enable device may be configured to receive the clock input signal from the chip enable device and use the clock input signal to gate the latch device based on a latch enable signal so as to selectively cutoff toggling of the clock input signal to the control input of the memory.

This section is intended to provide information relevant to understanding various technologies described herein. As the section's title implies, this is a discussion of related art that should in no way imply that it is prior art. Generally, related art may or may not be considered prior art. It should therefore be understood that any statement in this section should be read in this light, and not as any admission of prior art.
Integrated circuits typically include circuitry to perform data access functions to assist with memory operations. However, even when disabled or in standby, some of these data access functions may parasitically consume power. For instance, a significant portion of total dynamic power may be consumed due to toggling of control input pins of memory when disabled or in standby. As such, there exists a need to reduce control input pin power consumed when disabled or in standby.


A method, system and an apparatus minimize over-seeding and disruption of previously placed seed in an overlap area, when applying an agricultural product to a field with an agricultural product delivery arrangement having row units, by dispensing a predetermined first product amount equal to one hundred percent of a desired application to the field in a first pass through the entire field including the overlap area, and then dispensing a second product amount in a subsequent pass through the overlap area without raising row units out of the soil during the subsequent pass. The second product amount is determined as a function of a percentage the predetermined first product amount applied to the overlap area during the first pass that is disturbed by operative engagement of the row units with the soil during the subsequent pass over the overlap area.

Farmers typically use agricultural product delivery arrangements for seeding large agricultural fields. Such systems often include a tractor hitched in a conventional manner to an air cart and a "drill" (an agricultural implement typically including a number of row units). In operation, the tractor pulls the air cart and the drill through a field while the air cart pneumatically delivers agricultural product(s), such as seeds, fertilizer, and the like, to the drill. The drill, in turn, applies the agricultural product(s) to seed and/or fertilize the ground.
When seeding large fields, it is desirable to maximize use of the entire area of the field in order to ensure the most efficient use of space with the greatest crop yield possible. It is also desirable to minimize the overall travel path required by the product delivery arrangement in the field in order to ensure the most efficient use of the farmer's time and equipment. Also, minimizing the overall travel path helps to avoid undesirable disruption of already seeded ground.
However, many fields are shaped or disposed such that maximizing the entire area of the field requires at least some partially overlapping travel paths. For example, oddly shaped fields, or fields with obstacles, such as trees, structures, and the like, require additional maneuvering by the product delivery arrangement which may result in overlaps with earlier travel paths. Also, fields disposed on inclines may require travel paths at angles through the field, which may result in overlapping travel paths around the perimeter or "headlands" of the field. Such overlaps can cause double seeding, which results in heavier crops and potentially "lodging" (crops falling flat on the ground). Moreover, unnecessarily applying excess agricultural product can be costly.
In some prior approaches to precluding double seeding, application of the agricultural product is completely shut off during a subsequent pass in some row units of the drill as they pass through an overlap area. Application of the agricultural product through those row units is resumed as they emerge from the overlap area into an area that has not yet been planted. While this approach works reasonably well to preclude double seeding, it does not address the problem of the row units disrupting the previously planted seed in the overlap area during the subsequent pass through the overlap area.
In addition, there is typically an inherent time lag associated with completely stopping and re-starting a row unit, as a metering arrangement within the row unit that controls the application rate completely unloads and then re-loads itself with the agricultural product. This lag time can adversely affect the actual application rate.
Precise and accurate placement and/or other agricultural products in the soil is a critical factor in maximizing the crop yield. Having the row units disturb the previous placement of seed and/or agricultural product on subsequent passes through overlap areas is thus also undesirable.
Some prior approaches raise some of the row units out of contact with the soil during subsequent passes through overlap areas to avoiding double seeding and minimize disruption of previously planted soil in the overlap areas. This approach is not entirely satisfactory, however. To provide the capability for individually lifting sections of row units, and particularly for lifting each individual row unit free of the soil individually requires a level of complexity in the drill mechanism that undesirably drives up initial and maintenance cost of the drill, and it can lead to reduced reliability. Lifting sections of row units, or lifting individual row units, also typically results in some areas of the field going unplanted and/or untreated by agricultural chemicals and fertilizer applied by the row units.
What is needed is an improved technique for the application agricultural products which maximizes the entire area of a field while minimizing the drawbacks of overlapping with travel paths.

This patent is subject to a terminal disclaimer.

Agricultural product application in overlap areas


PSA process for oxygen production comprising (a) providing an adsorber having a first layer of adsorbent selective for water and a second layer of adsorbent selective for nitrogen, wherein the heat of adsorption of water on the adsorbent in the first layer is ≦about 14 kcal/mole at water loadings ≧about 0.05 to about 3 mmol per gram; (b) passing a feed gas comprising at least oxygen, nitrogen, and water successively through the first and second layers, adsorbing water in the first layer of adsorbent, and adsorbing nitrogen in the second layer of adsorbent, wherein the mass transfer coefficient of water in the first layer is in the range of about 125 to about 400 sec−1 and the superficial contact time of the feed gas in the first layer is between about 0.08 and about 0.50 sec; and (c) withdrawing a product enriched in oxygen from the adsorber.

Recent advances in process and adsorbent technology have enabled traditional large-scale pressure swing adsorption (PSA) systems to be scaled down to much smaller systems that operate in rapid cycles of very short duration. These small, rapid-cycle PSA systems may be utilized, for example, in portable medical oxygen concentrators that recover oxygen from ambient air. As the market for these concentrators grows, there is an incentive to develop increasingly smaller, lighter, and more portable units for the benefit of patients on oxygen therapy.
The impact of feed gas impurities on the adsorbent is a generic problem in many PSA systems, and the impact is especially serious in the small adsorbent beds required in small rapid-cycle PSA systems. For example, the water and carbon dioxide impurities in air can cause a significant decline in the performance of small PSA air separation systems by progressive deactivation of the adsorbent due to adsorbed impurities that are incompletely removed during regeneration steps of the PSA cycle. Because of this progressive deactivation, oxygen recovery will decline over time and adsorbent replacement may be required on a regular basis. Alternatively, the adsorbent beds may have to be oversized to account for progressive adsorbent deactivation. Both of these situations are undesirable because they increase the cost and weight of the oxygen concentrator system.
There is a need in the art for improved methods to remove impurities, particularly water, in the design and operation of small, portable, rapid-cycle PSA oxygen concentrators. This need is addressed by the embodiments of the invention described below and defined by the claims that follow.

Performance stability in shallow beds in pressure swing adsorption systems


Apparatus and methods for measuring in-situ applied torque in tubular operations. A torque cylinder has a first end and a second end. A torque rod is at least partially contained in the torque cylinder and is coupled to the first end of the torque cylinder. The torque rod extends longitudinally outward from the second end of the torque cylinder. A strain gauge is connected to the torque rod at a predetermined distance from the first end of the torque cylinder. The strain gauge is configured to measure in-situ the applied torque between two tubular drill string segments each coupled to a respective one of the torque cylinder and the torque rod.

The exacting application of torque is a requirement during all phases of oilfield drilling and completion. In response, many vendors employ a variety of methods to apply calibrated rotary motion to achieve desired levels of torque. With respect to calibration in general, typically a device that measures a linear dimension is calibrated against a certified length standard, a pressure gauge against a calibrated pressure gauge, and so forth, where calibration may be defined as the process of adjusting the output or indication on a measurement instrument to agree with the value of the applied standard. Calibration standards, in turn, are similarly calibrated against even more precise standards and so on until the reference is a national standard. A chain of authority is created such that the lowest link can refer up through cascading standards to a singular standard.
The calibration process with respect to torque measurements is largely disregarded in oilfield applications. Torque measuring devices are not typically calibrated by the application of a known force. Instead, load cells are used to measure torque referentially (as opposed to directly), and these load cells are calibrated by the application of force with no involvement of torque. In the United States, torque is typically measured in the number of pounds applied to a one foot long moment arm. To better understand why torque measurement is subordinated, perhaps an examination of pressure measurement would be informative. Pressure standards, known as dead weight testers, directly generate calibrated loads in pounds per square inch (psi). The load is generated by the application of a known weight on a piston of known diameter. Knowing the weight and the cylinder diameter enables the accurate calculation of the hydrostatic load measured in psi. A hierarchy of dead weight standards of ever increasing accuracy culminating with the national standard are available as desired.
Unfortunately, torque measurements do not lead to such straightforward solutions. There are no recognized national torque standards. Thus, torque measurements are made by indirect reference. Typically, oilfield processes measure torque referentially by the torque reaction of a measured reaction arm against a calibrated pressure sensor or mathematically by the application of a measured amount of electrical energy to a motor attached to a gearbox with a known gear reduction. Too often these referential torque measurements are made far away from the object of interest, in particular oilfield tubular connections. These tubular connections have precise torque requirements and often specify torque tolerances of only 10% away from nominal. Despite the best efforts of service providers, torque measurements often have significant errors, far exceeding the 10% allowance specified by connection suppliers.
In oilfield environments, electronic load cells are most often the source of data, and as such are frequently calibrated to 1% accuracy, for which there is no dispute with respect to the calibration method. The installation of load cells, however, is open to substantial criticism. The moment arm in this case is measured with a tape measure by identifying the center of rotation of a tong to the clevis attached to the tong. The snub line attached to the tong is either to be 90° from tong body or of a known angle. So far, it is easy to imagine a variety of errors that can affect the torque measurement, including arm length errors and snub line angle errors (in two planes).
Even assuming all the measurements are precise, yet another more insidious error is introduced: unknown, asymmetric, and spurious parasitic torque losses developed by the tong. Despite the best efforts of measuring the reaction torque of the tong body, the measurements do not quantify the actual torque applied to the connection of interest. In this case, only the application of torque by the use of a pipe tong is examined. Known methods of torque application suffer significant errors in torque measurement through faulty mechanics, such that these measurements suffer significant parasitic torque losses, the errors are not symmetric, and ultimately the torque measured has only a distant relationship with the torque applied.
Thus, there exists a need for a device that can measure torque in-situ regardless of its physical orientation.


A brake lever for an S-cam brake has a worm wheel (3) engaging the S-cam shaft and a worm screw (4) meshing therewith. A clutch wheel (6) on the worm screw forms a clutch (8) therewith under the bias of a compression spring (9). A control movement is transmitted from an external reference point to the clutch wheel via a pinion (15), a carrier wheel (16) and a control screw (18), the common axis of these three parts being perpendicular to the worm screw, wherein the control screw meshes with the clutch wheel. The carrier wheel can be turned relative to the pinion an angular distance corresponding to the desired slack and is biassed to one end position by a torsion spring (17), which is also used to engage a one-way clutch (19) between the carrier wheel and the control screw.

Especially for heavy road vehicles, such as trucks and buses, so called S-cam drum brakes are often used. Brake shoes provided with brake linings may be pressed apart against a brake drum by means of a generally S-shaped cam rotatable with a shaft (called the S-cam shaft) extending out of the brake drum. A lever, called the brake lever, attached to the S-cam shaft is connected to a piston rod of a preferably pneumatic brake cylinder in the vehicle underframe. Thus, at the admission of air under pressure to the brake cylinder a brake force will be transmitted from the piston rod via the brake lever to the S-cam shaft and the S-cam, which will press apart the brake shoes and thus apply the brakes.
When wear of the brake linings occurs, a longer stroke of the brake cylinder piston rod will be necessary before the brake is applied. It has become common to provide the brake lever with internal means for automatically turning a worm screw in engagement with a worm wheel, which is attached to the S-cam shaft, and thus adjusting the angular position of the brake lever in dependence on the brake lining wear; a so equipped lever is in the art called an automatic brake lever.
Most of the designs for such automatic brake levers are based on the so called piston stroke principle, i.e. the adjustment depends entirely on the piston rod stroke or in other words the angular movement of the brake lever past a certain value corresponding to the normal clearance or slack between the brake linings and the brake drum in the rest position.
More recently it has been found that different reasons speak for a more advanced principle--the so called clearance sensing principle. In this case the adjusting mechanism is able to differentiate between the piston rod stroke depending on the wear of the brake linings and that depending on the often considerable elasticity in the different parts between the brake cylinder and the brake drum. This means that the automatic adjustment reduces the clearance to the normal and desired value when it has become excessive, due for example to wear of the brake linings, whereas the mechanism ignores the influence of the elasticity.
Different requirements are imposed on a product of this kind. Generally speaking an automatic brake lever is a safety device working under extremely hard conditions as regards loads and environment. Further, the available space for the brake lever is often very limited. The reliability must be high and the periods between normal services as long as possible. Last but not least the price must be competitive.
Still further it is desirable to obviate the necessity for mounting the brake lever in a certain predetermined position, which is inconvenient not only at the initial mounting but even more after later servicing. The automatic brake lever shall thus preferably have a so called floating reference point or fixpoint.
The control arrangement for the brake lever ending with the clutch wheel on the worm screw shall have certain properties. Preferably the mechanism shall be slow-acting, which means that only a fraction of the whole excessive slack is to be reduced at each brake application. The control arrangement must therefore have a certain reduction, which may be obtained by a gearing between the control ring with its control arm and the clutch ring, namely in this case--coaxial with each other--the pinion, the carrier wheel and the control screw engaging the clutch ring perpendicular thereto.
Certain automatic brake levers with such a supplementary gearing are earlier known, such as U.S. Pat. No. 3 526 303, U.S. Pat. No. 4 484 665 and EP-A-30 766, which is regarded as the closest prior art.
A problem with a conventional brake lever of the kind where the necessary reference point for the slack adjusting function of the lever is found in a fix point in the vehicle chassis, is that the original mounting of the lever has to be done with certain accuracy in order to obtain the later proper function.
It is instead desirable to find a solution where the position of the reference point--and accordingly the angular position of the control arm relative to the lever housing--is immaterial for the proper function. The desirable condition can be called a floating reference point.
It is also desirable--in a slow-acting, clearance-sensing adjuster with a floating reference point--to have the adjustment performed during the return stroke, when the different parts are less strained than during the brake application stroke.

Brake lever for an S-cam automotive drum brake


An organic electroluminescence element comprising: an anode; a first emitting layer comprising at least a first host material and a first dopant; a second emitting layer comprising at least a second host material and a second dopant; and a cathode in the order mentioned: wherein the energy gap Egh1 of the first host material, the energy gap Egd1 of the first dopant, the energy gap Egh2 of the second host material, and the energy gap Egd2 of the second dopant satisfy the following formulas; and the luminescent intensity I1 at the maximum luminescent wavelength of an emission spectrum derived from the first emitting layer, and the luminescent intensity I2 at the maximum luminescent wavelength of an emission spectrum derived from the second emitting layer satisfy the following formula:Egh1>Egd1Egh2>Egd2Egd1>Egd2I1>3.5×I2.

Electroluminescence elements, which uses electroluminescence (electroluminescence being abbreviated to "EL" hereinafter), have a high visibility because of spontaneous emission and further have good features, such as excellent impact resistance, because they are completely solid elements. Therefore, attention has been paid to the use thereof as light emitting elements in various display devices.
The EL elements are classified into inorganic EL elements, wherein an inorganic compound is used for their luminescent material, and organic EL elements, wherein an organic compound is used therefor. In particular, the organic EL elements are being developed as next-generation light emitting elements since the elements enable to reduce the voltage to be applied largely, easily enable the formation of full-color devices, are small in power consumption and make panel-emission possible.
An organic EL element basically has a structure of an anode/an emitting layer/a cathode, as illustrated in FIG. 3.
This organic EL element 10 has an emitting layer 14 sandwiched between a pair of electrodes composed of an anode 12 and a cathode 13. The emitting layer 14 is usually composed of plural laminated layers. When an electric field is applied across the electrodes 12 and 13 in this element 10, electrons are injected from the cathode 13 and holes are injected from the anode 12. The electrons and the holes are recombined in the emitting layer 14 so as to cause an exciting state. When the exciting state returns to a ground state, energy is emitted as light.
FIG. 4 shows an energy diagram of the organic EL element in FIG. 3. In FIG. 4, a valence electron level EV0 (HOMO) and a conduction level EC0 (LUMO), which are energy levels of the emitting layer 14, are shown. Holes go in the layer 14 from the anode 12 and electrons go therein from the cathode 13. The holes and the electrons are combined with each other in the layer 14 so as to emit light.
There is known an element wherein the above-mentioned structure is used as a base and a hole injecting-transporting layer and/or an electron injecting layer are appropriately added, an example of the element being an element having the following structure: an anode/a hole injecting-transporting layer/an emitting layer/a cathode; or an anode/a hole injecting layer/a hole transporting layer/an emitting layer/an electron injecting layer/a cathode.
The emitting layer has the following functions:
(1) Injecting function: a function capable of injecting holes into the layer from an anode or a hole injecting layer, and injecting electrons into the layer from a cathode or an electron injecting layer when an electric field is applied.
(2) Transporting function: a function of transporting the injected charges (electrons and holes) by the electric field.
(3) Light emitting functions: a function of supplying a field where the electrons and the holes are recombined and inducing light emission from this recombination.
The hole injecting-transporting layer has a function of injecting holes into the layer from an anode and transporting the holes into an organic emitting layer. A hole injecting layer and a hole transporting layer may be separately formed. The electron injecting layer has a function of injecting electrons into the layer from a cathode, and transporting the electrons into the organic emitting layer.
In order to make light emission in the emitting layer more intense, a technique of adding a very small amount of a fluorescent molecule (dopant) thereto is known.
FIG. 5 illustrates an energy diagram of an organic EL element to which a dopant is added. In this figure, ECh represents the conduction level of the host thereof; EVh, the valence electron level of the host; ECd, the conduction level of the dopant; and EVd, the valence electron level of the dopant. Egh and Egd represent the energy gap (difference between the ECh and the EVh) of the host and the energy gap (difference between the ECd and the EVd) of the dopant, respectively.
The dopant receives the energy of the excited host effectively so as to enhance the light emitting efficiency.
The method for obtaining multicolor from the luminescence of an organic EL element is roughly classified into the following three methods:
(1) A method of taking out lights of three colors from white luminescence emitted from an organic EL element by using three colors, red, green and blue filters.
(2) A method of converting blue luminescence emitted from an blue EL element to light of other colors by a fluorescent layer formed on the light-taking-out side of its emitting layer.
(3) A method of arranging blue, red and green emitting layers side by side on the same substrate.
For these methods, organic EL elements giving a high luminance and having a long durability have been demanded. For example, for the methods (1) and (2), the following has been earnestly desired: organic EL elements which emit light having a bluish green or white broad band (wide spectrum) and which have a half life of several ten thousands of hours or more for an initial luminance of several hundreds nit.
Various element structures have been investigated for such a desire.
As one method out of them, a method for making an organic emitting layer into plural layers, thereby obtaining white or broad band luminescence is suggested as follows:
(1) A way of making an organic emitting layer into a bi-layered structure, the first emitting layer in the anode side thereof being a blue emitting layer made of an aluminum complex compound, and the second emitting layer in the cathode side being a red emitting layer made of an aluminum complex compound containing a red fluorescent material, thereby taking out white light (see, for example, EP0643549).
(2) A way of making an organic emitting layer into a bi-layered structure, the first emitting layer in the anode side thereof being a blue emitting layer made of a distyrylarylene-based compound, and the second emitting layer in the cathode side being an emitting layer wherein a red fluorescent material is added to an aluminum complex compound emitting green light, thereby taking out white light (see, for example, U.S. Pat. No. 5,503,910).
(3) A way of incorporating coumarin and rubrene as dopants into an emitting layer which is a mixture layer of an electron transporting compound made of an aluminum complex and a hole transporting compound made of a diamine compound, thereby emitting light having a green component and an orange component (see, for example, WO98/08360).
(4) A way of doping a host material made of a distyrylarylene-based compound with two or more fluorescent materials different in color, thereby forming two emitting layers (see, for example, JP-A-12-68057).
These conventional techniques are ways for causing plural kinds of dopants equally to emit light to obtain broad band or white luminescence. The light emitted from the organic EL element is light wherein various wavelengths are mixed.
However, there is not known any organic EL element which has a multi-layered, laminated structure, emits light with a high color purity and a narrow band (narrow spectrum), and has a long durability.
In light of the above-mentioned problems, an object of the present invention is to provide an organic EL element which emits light with a high color purity and a narrow band and has a long durability.


A pivot assembly provides an economical means for reducing the load on a manually operated hand jack by providing a pivot point on the body of a connecting rod which allows for an additional degree of movement. The pivot assembly may include a thrust bearing to further reduce friction on the connection rod.

Fluid valves having throttling elements actuated by sliding stems are generally known in the art for regulating fluid flow in process control systems. These fluid valves may include control valves and regulators. The fluid valves are typically coupled to an actuator, which may generate force hydraulically, pneumatically, or electrically. In the case of actuator failure, a manually operated hand jack may be used to move a valve stem assembly so that a throttling element is placed in a safe open or closed position under emergency conditions. Previously known hand jacks may include a bracket, a lever, a pivot pin, and a rod. A handwheel may be attached to the rod to facilitate application of manual torsion force to the rod. Rotation of the rod may pivot the lever about the pin. The lever engages a valve stem, the actuator, or some other component of the valve stem assembly such that rotation of the lever raises or lowers the valve stem, thus opening or closing the valve.
Conventional hand jacks may disadvantageously generate unwanted friction and bending forces during operation. As the lever pivots from an open to close position or close to open position, a point at which the rod is coupled to the lever may follow a generally arcuate path. The bracket usually engages another portion of the rod such that the rod is held in a substantially constant attitude with respect to the valve stem. With one portion of the rod substantially in place and a free end of the rod movable through an arcuate path, operation of the hand jack causes significant bending forces on the rod. The bending forces at the rod/lever coupling thereby increase friction during operation and therefore the force required to operate the hand jack. These stresses on the rod may also magnify the load on coupling mechanisms, e.g., mounting bolts, that secure the hand jack to the valve, and may increase the wear and tear on the device. Moreover, the load on the mounting bolts may increase the risk of structural failure.

Pivot and bearing assembly for a manual valve operator


A pipe conveyor system which operates to assemble and disassemble a plurality of pipes.

A pipe conveyor system which operates to assemble and disassemble a plurality of pipes.
A numerous and wide variety of pipe can be obtained in sections which can be assembled and disassembled to generate a required length of pipe. Because the pipe sections may be difficult to transport or assemble and disassemble by hand, a variety of devices have been built to assist in the transport, assembly and disassembly of certain types of pipe sections, such as well drilling and well casement pipe.
With respect to irrigation pipe sections (and other types of pipe sections laid on the surface of the ground or in trenches), however, the conventional manner of assembly or disassembly appears to remain the use of manual labor to lift each section from the ground, truck, trailer, or other transport means, to align the irrigation pipe sections end to end along the desired path on the support surface, and to join the opposed ends by telescopic or other mated engagement. While the use of manual labor to assemble or disassemble irrigation pipe sections (or other types or kinds of pipe sections) can be time consuming, dangerous and expensive, it appears that no device has been improvised to assist in the assembly or disassembly of the pipe sections.


A geared motor in which user needs for change gear ratios are met with flexibility and reliability, and an increase in noise is suppressed. The geared motor comprises a motor unit and a change gear unit for transmitting rotational power from this motor unit in combination. A simple planetary roller unit including a simple planetary roller mechanism and a casing for accommodating this simple planetary roller mechanism is interposed between the change gear unit and the motor unit. The simple planetary roller mechanism has a sun roller, planetary rollers, and a ring roller. Flange portions spreading outward in the radial directions of the sun roller are formed on both axial ends of the casing. One of the flange portions is coupled to the motor unit, and the other is to the change gear unit. Moreover, the geared motor is configured so that rotational power from the motor unit is transmitted to the change gear unit through the simple planetary roller unit.

1. Field of the Invention
The invention relates to a geared motor having a motor unit and a change gear unit for transmitting rotational power from this motor unit in combination, and a geared motor series from which this geared motor can be constructed.
2. Description of the Related Art
Geared motors comprising a motor unit for generating rotational power and a change gear unit for reducing or increasing the speed of the rotational power in combination are widely used in every industrial field, because their motor speeds are mechanically reduced or increased, they are capable operating their motor units in a most efficient state (revolution range).
For example, a conventional geared motor 1 shown in FIG. 10 comprises a motor unit 2 and a change gear unit 4 for transmitting rotational power from the motor unit 2 in combination.
This motor unit 2 has a mounting surface consisting of a square motor flange 10 formed thereon at the top side of its motor shaft 6. This motor flange 10 has bolt holes 10A formed therethrough at the four corners. The motor shaft 6 is located at the center of the motor flange 10.
The motor unit 2 outputs rotational power through the motor shaft 6. As shown in FIG. 9, the end of this motor shaft 6 is splined so as to support a helical motor pinion 8 rotatively.
The change gear unit 4 has a three-stage reduction structure. Specifically, the change gear unit 4 comprises: a first gear 12 meshing with the motor pinion 8; a first pinion 14 for making coaxial, integral rotation with the first gear 12; a second gear 16 meshing with the first pinion 14; a second pinion 18 for making coaxial, integral rotation with the second gear 16; an output shaft gear 20 meshing with the second pinion 18; an output shaft 22 supported by a bearing, for making integral rotation with the output shaft 22; and a casing 24 for accommodating these change gear mechanisms.
A shaft insertion hole 24A to which the motor shaft 6 is inserted is formed through the casing 24. The casing 24 is also provided with tapped holes 24B formed at the individual corners of a square with the shaft insertion hole 24A at the center. The shaft insertion hole 24A and the four tapped holes 24B are arranged to coincide with the motor shaft 6 and the four bolt holes 10A in the motor flange 10 of the motor unit 2, respectively, so that the motor unit 2 and the change gear unit 4 are coupled to each other by four bolts 26, as shown in FIG. 10.
In this geared motor 1, rotational power from the motor unit 2 is transmitted through the individual pinions and gears to the output shaft 22 at a predetermined reduction ratio.
For this type of geared motor 1, in general, a plurality of serialized change gear units 4 set at change gear ratios with predetermined intervals (common ratios) are provided in advance. Of these, one change gear unit 4 having the change gear ratio closest to an actually-required change gear ratio is combined with the motor unit 2 to construct a geared motor 1.
As described above, a user of the geared motor 1 selects a change gear unit 4 having the most appropriate change gear ratio from among the series with a variety of change gear ratios. According to the use patterns of the geared motor 1, however, a modification to the change gear ratio is sometimes needed afterwards. Possible measures to be taken here include the following:
1) Replace the change gear unit 4 with a new one having an optimum change gear ratio
2) Add a change gear unit having an adjusting change gear ratio to between the change gear unit 4 and the motor unit 2.
The measures 1), however, require purchase of the new change gear unit 4, giving rise to an increase in cost and a problem of wasting the change gear unit 4 used heretofore.
As for the measures 2), the change gear unit 4 used previously was intended for to-motor coupling in the first place. Therefore, the interposition of a change gear unit between the change gear unit 4 and the motor unit 2 was often difficult in practice, and involved considerable problems. The reasons therefor will be described in concrete terms hereinafter.
A first problem is that the change gear unit 4 has a mounting surface structure of xe2x80x9creceivingxe2x80x9d type alone, and hence it is physically difficult to couple an additional (other-than-motor-unit) change gear unit or the like (hereinafter, referred to as insert unit) thereto.
A motor unit 2 is always coupled to an apparatus to be driven (mating machine) such as the change gear unit 4. To facilitate this coupling, there is typically provided a motor flange 10 as shown in FIG. 10. This aims to insert bolts 26 to the bolt holes 10A from the motor side, and threadedly engage the bolts 26 with the tapped holes 24B on the mating-machine side to allow the coupling.
As a result of this, many reduction gear units 4 simply have a structure of xe2x80x9creceivingxe2x80x9d it. More specifically, reduction gear units 4 often have nothing but simple tapped holes 24B formed at the individual corners of a square around their shaft insertion hole 24A to which the motor shaft 6 is inserted; that is, there is little assumption that the coupling may be established by bolting from the reduction-unit-4 side.
Turning now to an insert unit itself, suppose that the change gear mechanism in the insert unit has a parallel axis gear structure containing pinions and gears in combination. In a single-stage reduction mechanism, it would be impossible for the insert unit to establish coaxiality between the motor shaft 6 inserted thereto and its own output shaft for transmitting the rotation of the motor shaft 6 to the reduction gear unit 4. Therefore, two or more stages (two or more pairs of gears and pinions) are logically required in order to make coaxial the motor shaft 6 and the output shaft in the insert unit. The insertion unit thus becomes complicated in internal structure, as well as extended along the axial direction of the motor shaft 6.
A second problem is that even though the main objective is to make an adjustment in change gear ratio, it is not always possible to achieve a user-intended change gear ratio.
Change gear units, as described before, are serialized with change gear ratios of regular intervals in advance. Therefore, combining the same with serialized insert units of another types cannot always achieve a desired change gear ratio. That is, combinations of change gear ratios obtainable from ordinary geared speed-change units lead to only a limited variation of change gear ratios, failing to make fine adjustments according to an actual change gear ratio needed.
A third problem is that combining two change gear units increases noise greatly. To be more specific, there occur the problems that the change gear units combined produce resonance with each other, and that a rise in the number of gears makes the gears themselves produce higher noise.
The present invention has been achieved in view of the foregoing problems. It is thus an object of the present invention to provide a geared motor which can meet user needs for change gear ratios with flexibility and reliability as well as suppresses an increase in noise, and a geared motor series from which a plurality of types of such geared motors can be constructed.
The invention according to claim 1 achieves the foregoing object by the provision of a geared motor comprising a motor unit and a change gear unit for transmitting rotational power from the motor unit in combination, the change gear unit being arranged with its input shaft coaxial to a motor shaft of the motor unit, wherein: a simple planetary roller unit including a simple planetary roller mechanism and a casing for accommodating the simple planetary roller mechanism is interposed between the change gear unit and the motor unit, the simple planetary roller mechanism having a sun roller, a planetary roller retained by a carrier, and a ring roller, the planetary roller making rolling contact with the outer periphery of the sun roller and with the inner periphery of the ring roller; and flange portions spreading outward in the radial directions of the sun roller are formed on the casing for accommodating the simple planetary roller mechanism, at both ends in the axial direction of the sun roller, and one of the flange portions is coupled to a casing of the motor unit and the other is coupled to a casing of the change gear unit, and the geared motor is configured so that rotational power from the motor unit is coaxially transmitted to the change gear unit through the simple planetary roller unit.
This geared motor adopts a simple planetary roller mechanism as the insert unit. The simple planetary roller mechanism is capable of fine adjustments to the outside diameter of its ring roller, and therefore can flexibly meet a more delicate change gear ratio as compared with geared speed change structures which are controlled by the numbers of teeth, modules, and the like. Besides, this simple planetary roller mechanism has the advantages that its input and output shafts can be easily made coaxial, and that higher change gear ratios can be obtained from a compact configuration.
Then, the present inventors has found that the characteristic configurations of the simple planetary roller mechanism and the casing supporting the same can be utilized to provide a flange structure on both sides, and has conceived that it is thereby possible to solve a number of problems existing heretofore, such as noises and fine adjustments to the change gear ratio, in whole.
More specifically, in this geared motor, the casing for accommodating the simple planetary roller mechanism has a double-flange structure. Therefore, even if the mating machines (change gear unit, motor unit) have structural difficulty in being coupled to other units, the flanges allow easy coupling therebetween. The reason is that it is possible to insert coupling bolts from the flange sides and threadedly engage the same with tapped holes in the mating machines.
By the way, it is publicly known, in the sense of general concepts, that transmission apparatuses comprising traction rollers can reduce noise as compared with geared transmission apparatuses. When the present inventors adopted a transmission apparatus of simple planetary roller mechanism and interposed this simple planetary roller unit to between a reduction gear unit and a motor unit, however, they found an unexpected noise reduction effect that the total noise becomes significantly lower than before the interposition, i.e., when the change gear unit and the motor unit were directly coupled to each other (U.S. patent application Ser. No. 09/526,284).
Although there are many uncertainties, the reason for this seems to be that this simple planetary roller mechanism has a characteristic power transmission structure utilizing the rotations and revolutions of its planetary rollers, and transmits rotational power by means of friction between the contact surfaces of (the plurality of) rollers. Here, the individual contact surfaces and the portions supporting the planetary rollers can well absorb the vibrations and noises which used to occur from the resonance between the motor unit and the change gear unit. In any case, the effect of noise reduction is as dramatic as far beyond expectations.
Moreover, as a result of forming flange portions on both sides of the casing, it becomes possible to couple any motor unit and change gear unit across the flange sides, permitting easy provision of a geared motor series including a variety of combinations. That is, since the two flange portions may be formed into different configurations (different bolt arrangements), even such motor units and change gears unit as never used to be combinable can be coupled to each other through the interposition of this simple planetary roller unit. This allows the provision of a wide-ranged geared motor series.
Besides, upon the interposition of this simple planetary roller mechanism to between a motor unit and a change gear unit coupled previously, both of the flange portions may be provided with a plurality of bolt holes formed therethrough along the axial direction of the sun roller so as to be identical to each other in arrangement. Then, mounting bolts inserted to the bolt holes may couple one the flange portions to the casing of the motor unit and the other to the casing of the change gear unit.
Of course it is also possible that both of the flange portions are provided with the above-mentioned bolt holes in different arrangements as well as those bolt holes in identical arrangements. This provides further versatility for applications.
Moreover, in the foregoing invention, the ring roller may be fixed to the casing for accommodating the simple planetary roller mechanism so that the rotation of the ring roller is restrained. Then, a shaft insertion hole is formed on (or through) the rotational center of the sun roller, and either the motor shaft of the motor unit or the input shaft of the change gear unit is inserted to the shaft insertion hole. A shaft insertion hole is formed on (or through) the rotational center of the carrier, and the other of the motor shaft and the input shaft is inserted to the shaft insertion hole. Thereby, rotational power from the motor unit is coaxially transmitted to the change gear unit through the simple planetary roller mechanism.
According to this invention, it is possible to install the simple planetary roller unit in place of a coupling which used to couple the motor shaft and the input shaft of the change gear unit. Therefore, the simple planetary roller unit offers the same functions as those of a shaft coupling even after the addition of speed change function.
Incidentally, xe2x80x9cchange gear unitxe2x80x9d employed in the present invention means a unit that changes the rotational speed of input rotational power for output, including a reduction unit, a step-up unit, and the like.
The nature, principle, and utility of the invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings in which like parts are designated by like reference numerals or characters.


A battery operated, rotatable platform display device for use in retail establishments. The display device employs a friction clutch provided between the base of the rotatable platform and an underlying drive plate upon which the rotatable platform is supported via a rotatable drive shaft.

Rotatable platform display units for retail display purposes in stores are known. Typical rotatable platform display units employ a driven table which is geared to a motor. Most such units are powered directly from a local 110 VAC or 220 VAC power grid and, therefore, lack mobility. Further, typical current turntable drive devices employ complicated positive clutch arrangements and are not readily adaptable to use in mobile rotatable turntable displays. Neither are they adaptable for use when they are required to carry substantial loads and, at the same time, are required to operate safely even when children are likely to be in the vicinity of, and even play with, the display unit.
It would be advantageous to provide a battery-operated rotatable turntable display unit from which the turntable can be easily removed, and with which consumers can come into contact without fear of injury.